Publications reported by three months

1.Jarząbek D.M., Milczarek M., Nosewicz S., Bazarnik P., Schift H., Size Effects of Hardness and Strain Rate Sensitivity in Amorphous Silicon Measured by Nanoindentation, METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, ISSN: 1073-5623, DOI: 10.1007/s11661-020-05648-w, pp.1-9, 2020
Jarząbek D.M., Milczarek M., Nosewicz S., Bazarnik P., Schift H., Size Effects of Hardness and Strain Rate Sensitivity in Amorphous Silicon Measured by Nanoindentation, METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, ISSN: 1073-5623, DOI: 10.1007/s11661-020-05648-w, pp.1-9, 2020

Abstract:
In this work, dynamic mechanical properties of amorphous silicon and scale effects were investigated by the means of nanoindentation. An amorphous silicon sample was prepared by plasma-enhanced chemical vapor deposition (PECVD). Next, two sets of the samples were investigated: as-deposited and annealed in 500 C for 1 hour. A three-sided pyramidal diamond Berkovich’s indenter was used for the nanoindentation tests. In order to determine the strain rate sensitivity (SRS), indentations with different loading rates were performed: 0.1, 1, 10, 100 mN/min. Size effects were studied by application of maximum indentation loads in the range from 1 up to 5 mN (penetrating up to approximately one-third of the amorphous layer). The value of hardness was determined by the Oliver–Pharr method. An increase of hardness with decrease of the indentation depth was observed for both samples. Furthermore, the significant dependence of hardness on the strain rate has been reported. Finally, for the annealed samples at low strain rates a characteristic ‘‘elbow’’ during unloading was observed on the force-indentation depth curves. It could be attributed to the transformation of (b-Sn)-Si to the PI (pressure-induced) a-Si end phase.

2.Pisarski D., Konowrocki R., Jankowski Ł., Scalable distributed optimal control of vibrating modular structures, STRUCTURAL CONTROL AND HEALTH MONITORING, ISSN: 1545-2255, DOI: 10.1002/stc.2502, pp.1-21, 2020
Pisarski D., Konowrocki R., Jankowski Ł., Scalable distributed optimal control of vibrating modular structures, STRUCTURAL CONTROL AND HEALTH MONITORING, ISSN: 1545-2255, DOI: 10.1002/stc.2502, pp.1-21, 2020

Abstract:
A scalable optimal control method for structural vibration mitigation is studied. The method relies on a structure's partitioning that leads to a set of dynamically interconnected subsystems. Each subsystem is operated with an individual subcontroller that collects the local state information and collaborates with the neighboring subcontrollers to estimate a short time prediction of the interconnecting forces defining the subsystem's boundary conditions. Using the extended model that represents the subsystem's dynamics together with the evolution of its boundary conditions, each subcontroller computes the control decision based on the solution to a finite‐time horizon optimal control problem. In order to cope with the changes in the boundary conditions, the optimal solution is computed repetitively according to the receding horizon scheme. The method is validated numerically for a cantilever structure equipped with actively controlled electromagnetic actuators and subjected to a variety of initial condition scenarios. The performance of the designed controller is tested by comparisons to the centralized and isolated decentralized controllers. The introduced system partitioning and distributed controller allow performing parallel computing which makes the method fully scalable and applicable to large‐scale structures. The computational complexity of the designed distributed control is studied for different settings in the modeling of the subsystem's boundary conditions.

Keywords:
active control, distributed control, modular structure, scalable optimization, stabilization

3.Jia B., Rusinek A., Pesci R., Bahi S., Bernier R., Thermo-viscoplastic behavior of 304 austenitic stainless steel at various strain rates and temperatures: testing, modeling and validation, INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES, ISSN: 0020-7403, DOI: 10.1016/j.ijmecsci.2019.105356, Vol.170, pp.105356-1-18, 2020
Jia B., Rusinek A., Pesci R., Bahi S., Bernier R., Thermo-viscoplastic behavior of 304 austenitic stainless steel at various strain rates and temperatures: testing, modeling and validation, INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES, ISSN: 0020-7403, DOI: 10.1016/j.ijmecsci.2019.105356, Vol.170, pp.105356-1-18, 2020

Abstract:
This paper presents a systematic study of the thermo-viscoplastic behavior of a 304 austenitic stainless steel (ASS). The experiments were conducted over a wide range of strain rates (10−3 s−1 to 3270 s−1) and temperatures (-163°C to 172°C), for which the deformation behavior of 304 ASS becomes more complex due to the strain-induced martensitic transformation (SIMT) effect. Dynamic tests at low/elevated temperatures were conducted using the Hopkinson technique coupled with a cooling device/heating furnace, and temperature distribution within the specimen was verified to be uniform. Experimental results showed that the strain hardening rate of 304 ASS was strongly affected by SIMT effect. For quasi-static tests (10−3 s−1 to 1 s−1) at low temperatures (-163°C to -20°C), the stress-strain relations exhibited an S-shape and a second strain hardening phenomenon. The strain rate sensitivity and temperature sensitivity of 304 ASS were also different from metallic materials deformed by dislocation glide. Several unexpected phenomena including the negative strain rate sensitivity and the changing temperature sensitivity from quasi-static to dynamic tests were observed. Based on experimental results, an extension of the Rusinek-Klepaczko (RK) model considering SIMT effect was used to simulate the deformation behavior of 304 ASS: it predicted flow stress curves of 304 ASS above -60°C correctly. In addition, to validate the extended RK model and the identified model parameters, numerical simulations of ballistic impact tests of 304 ASS plates at various temperatures were carried out, showing a good agreement with experiments.

Keywords:
304 austenitic stainless steel, Strain rate sensitivity, Temperature sensitivity, Constitutive model, Ballistic impact test

4.Żołek N., Rix H., Botwicz M., Analysis of estimation of optical properties of sub superficial structures in multi layered tissue model using distribution function method, Computer Methods and Programs in Biomedicine, ISSN: 0169-2607, DOI: 10.1016/j.cmpb.2019.105084, pp.105084-1-9, 2020
Żołek N., Rix H., Botwicz M., Analysis of estimation of optical properties of sub superficial structures in multi layered tissue model using distribution function method, Computer Methods and Programs in Biomedicine, ISSN: 0169-2607, DOI: 10.1016/j.cmpb.2019.105084, pp.105084-1-9, 2020

Abstract:
The research is based on the analysis of the superposition of cumulative distributions of time of flight of photons. This approach allows for detailed analysis of small variations in characteristics of time of flight of photons caused by an electromagnetic propagation in highly scattering non-homogeneous media. The method presented, based on the variation of statistical minimum distance estimation, is compared to the method of standard curve fitting. It is analyzed by fitting the results obtained from Monte-Carlo simulations of light propagation in the turbid medium to the data from the simulated measurements. Results:The analysis is carried out for a vast range of optical properties of two layered medium in reflectance geometry. Conclusions: The method allows the estimation of the optical parameters despite the noise in the measured signal, with higher accuracy and generally with smaller number of error function evaluations.

Keywords:
Optical properties, Approximation, Light propagation, Time of Flight of Photons, Monte-Carlo simulations, Cumulative distributions

5.Białecki S., Nałęcz-Jawecki P., Kaźmierczak B., Lipniacki T., Traveling and standing fronts on curved surfaces, PHYSICA D-NONLINEAR PHENOMENA, ISSN: 0167-2789, DOI: 10.1016/j.physd.2019.132215, Vol.401, pp.132215-1-8, 2020
Białecki S., Nałęcz-Jawecki P., Kaźmierczak B., Lipniacki T., Traveling and standing fronts on curved surfaces, PHYSICA D-NONLINEAR PHENOMENA, ISSN: 0167-2789, DOI: 10.1016/j.physd.2019.132215, Vol.401, pp.132215-1-8, 2020

Abstract:
We analyze heteroclinic traveling waves propagating on two dimensional manifolds to show that the geometric modification of the front velocity is proportional to the geodesic curvature of the frontline. As a result, on surfaces of concave domains, stable standing fronts can be formed on lines of constant geodesic curvature. These lines minimize the geometric functional describing the system’s energy, consisting of terms proportional to the front line-length and to the inclosed surface area. Front stabilization at portions of surface with negative Gaussian curvature, provides a mechanismof pattern formation. In contrast to the mechanism associated with the Turing instability, the proposed mechanism requires only a single scalar bistable reaction–diffusion equation and connects the intrinsic surface geometry with the arising pattern. By considering a system of equations modeling boundary-volume interactions, we show that polarization of the boundary may induce a corresponding polarization in the volume.

Keywords:
Heteroclinic traveling waves, Standing fronts, Geodesic curvature, Negative Gaussian curvature, Domain polarization, Pattern formation

6.Kovalchuk V., Mladenov I.M., Mechanics of infinitesimal gyroscopes on Mylar balloons and their action-angle analysis, MATHEMATICAL METHODS IN THE APPLIED SCIENCES, ISSN: 0170-4214, DOI: 10.1002/mma.6099, pp.1-12, 2020
Kovalchuk V., Mladenov I.M., Mechanics of infinitesimal gyroscopes on Mylar balloons and their action-angle analysis, MATHEMATICAL METHODS IN THE APPLIED SCIENCES, ISSN: 0170-4214, DOI: 10.1002/mma.6099, pp.1-12, 2020

Abstract:
Here, we apply the general scheme for description of mechanics of infinitesimal bodies in Riemannian spaces to the example of geodetic and non-geodetic (for two different model potentials) motions of infinitesimal rotators on the Mylar balloon. The structure of partial degeneracy is investigated with the help of the corresponding Hamilton-Jacobi equation and action-angle analysis. In all situations it was found that for any of the sixth disjoint regions in the phase space among the three action variables only two are essential for the description of our models at the level of the old quantum theory (according to the Bohr-Sommerfeld postulates). Moreover, in both non-geodetic models, the action variables were intertwined with the quantum number N corresponding to the quantized value of the radius r of the inflated Mylar balloon.

Keywords:
action-angle analysis, affinely-rigid bodies, Bohr-Sommerfeld quantum theory, Hamilton-Jacobi equation, infinitesimal gyroscopes, Mylar balloons, residue analysis.

7.Zaszczyńska A., Sajkiewicz P., Gradys A., Piezoelectric Scaffolds as Smart Materials for Neural Tissue Engineering, Polymers, ISSN: 2073-4360, DOI: 10.3390/polym12010161, Vol.12, pp.161-1-25, 2020
Zaszczyńska A., Sajkiewicz P., Gradys A., Piezoelectric Scaffolds as Smart Materials for Neural Tissue Engineering, Polymers, ISSN: 2073-4360, DOI: 10.3390/polym12010161, Vol.12, pp.161-1-25, 2020

Abstract:
Injury to the central or peripheral nervous systems leads to the loss of cognitive and/or sensorimotor capabilities, which still lacks an effective treatment. Tissue engineering in the post-injury brain represents a promising option for cellular replacement and rescue, providing a cell scaffold for either transplanted or resident cells. Tissue engineering relies on scaffolds for supporting cell differentiation and growth with recent emphasis on stimuli responsive scaffolds, sometimes called smart scaffolds. One of the representatives of this material group is piezoelectric scaffolds, being able to generate electrical charges under mechanical stimulation, which creates a real prospect for using such scaffolds in non-invasive therapy of neural tissue. This paper summarizes the recent knowledge on piezoelectric materials used for tissue engineering, especially neural tissue engineering. The most used materials for tissue engineering strategies are reported together with the main achievements, challenges, and future needs for research and actual therapies. This review provides thus a compilation of the most relevant results and strategies and serves as a starting point for novel research pathways in the most relevant and challenging open questions.

Keywords:
neural tissue engineering, piezoelectric scaffolds, smart materials, polymers

8.Zhang Q., Hou J., Jankowski Ł., Bridge Damage Identification Using Vehicle Bump Based on Additional Virtual Masses, SENSORS, ISSN: 1424-8220, DOI: 10.3390/s20020394, Vol.20, No.2, pp.394-1-394-23, 2020
Zhang Q., Hou J., Jankowski Ł., Bridge Damage Identification Using Vehicle Bump Based on Additional Virtual Masses, SENSORS, ISSN: 1424-8220, DOI: 10.3390/s20020394, Vol.20, No.2, pp.394-1-394-23, 2020

Abstract:
Structural damage identification plays an important role in providing effective evidence for the health monitoring of bridges in service. Due to the limitations of measurement points and lack of valid structural response data, the accurate identification of structural damage, especially for large-scale structures, remains difficult. Based on additional virtual mass, this paper presents a damage identification method for bridges using a vehicle bump as the excitation. First, general equations of virtual modifications, including virtual mass, stiffness, and damping, are derived. A theoretical method for damage identification, which is based on additional virtual mass, is formulated. The vehicle bump is analyzed, and the bump-induced excitation is estimated via a detailed analysis in four periods: separation, free-fall, contact, and coupled vibrations. The precise estimation of bump-induced excitation is then applied to a bridge. This allows the additional virtual mass method to be used, which requires knowledge of the excitations and acceleration responses in order to construct the frequency responses of a virtual structure with an additional virtual mass. Via this method, a virtual mass with substantially more weight than a typical vehicle is added to the bridge, which provides a sufficient amount of modal information for accurate damage identification while avoiding the bridge overloading problem. A numerical example of a two-span continuous beam is used to verify the proposed method, where the damage can be identified even with 15% Gaussian random noise pollution using a 1-degree of freedom (DOF) car model and 4-DOF model.

Keywords:
structural health monitoring, damage identification, vehicle bump, additional virtual mass, bridge

9.Wang L., Lv H., Liu L., Zhang Q., Nakielski P., Si Y., Cao J., Li X., Pierini F., Yu J., Ding B., Electrospun nanofiber-reinforced three-dimensional chitosan matrices: Architectural, mechanical and biological properties, JOURNAL OF COLLOID AND INTERFACE SCIENCE, ISSN: 0021-9797, DOI: 10.1016/j.jcis.2020.01.016, Vol.565, pp.416-425, 2020
Wang L., Lv H., Liu L., Zhang Q., Nakielski P., Si Y., Cao J., Li X., Pierini F., Yu J., Ding B., Electrospun nanofiber-reinforced three-dimensional chitosan matrices: Architectural, mechanical and biological properties, JOURNAL OF COLLOID AND INTERFACE SCIENCE, ISSN: 0021-9797, DOI: 10.1016/j.jcis.2020.01.016, Vol.565, pp.416-425, 2020

Abstract:
The poor intrinsic mechanical properties of chitosan hydrogels have greatly hindered their practical applications. Inspired by nature, we proposed a strategy to enhance the mechanical properties of chitosan hydrogels by construction of a nanofibrous and cellular architecture in the hydrogel without toxic chemical crosslinking. To this end, electrospun nanofibers including cellulose acetate, polyacrylonitrile, and SiO2 nanofibers were introduced into chitosan hydrogels by homogenous dispersion and lyophilization. With the addition of 30% cellulose acetate nanofibers, the cellular structure could be maintained even in water without crosslinking, and integration of 60% of the nanofibers could guarantee the free-standing structure of the chitosan hydrogel with a low solid content of 1%. Moreover, the SiO2 nanofiber-reinforced chitosan (SiO2 NF/CS) three-dimensional (3D) matrices exhibit complete shape recovery from 80% compressive strain and excellent injectability. The cellular architecture and nanofibrous structure in the SiO2 NF/CS matrices are beneficial for human mesenchymal stem cell adhesion and stretching. Furthermore, the SiO2 NF/CS matrices can also act as powerful vehicles for drug delivery. As an example, bone morphogenetic protein 2 could be immobilized on SiO2 NF/CS matrices to induce osteogenic differentiation. Together, the electrospun nanofiber-reinforced 3D chitosan matrices exhibited improved mechanical properties and enhanced biofunctionality, showing great potential in tissue engineering.

Keywords:
Chitosan hydrogel, Electrospun nanofiber, Mechanical property, Nanofibrous matrix, Tissue engineering

10.Konowrocki R., Chojnacki A., Analysis of rail vehicles’ operational reliability in the aspect of safety against derailment based on various methods of determining the assessment criterion, EKSPLOATACJA I NIEZAWODNOŚĆ - MAINTENANCE AND RELIABILITY, ISSN: 1507-2711, DOI: 10.17531/ein.2020.1.9, Vol.22, No.1, pp.73-85, 2020
Konowrocki R., Chojnacki A., Analysis of rail vehicles’ operational reliability in the aspect of safety against derailment based on various methods of determining the assessment criterion, EKSPLOATACJA I NIEZAWODNOŚĆ - MAINTENANCE AND RELIABILITY, ISSN: 1507-2711, DOI: 10.17531/ein.2020.1.9, Vol.22, No.1, pp.73-85, 2020

Abstract:
The article features the results of computer and experimental research on operational issues in the aspect of safety in relation to a freight wagon derailment on a railway track. It presents the knowledge regarding the methods of assessing the operational safety of rail vehicles on railroad tracks for the purpose of comparative analysis. The theoretical analyses were performed based on several methods that assess the safety of their derailments, qualifying for operational reliability, comparing them with the results obtained from experimental research. For the purpose of the research, a computer model of rail vehicle- railway track was created. It took into consideration dynamic parameters of elements used in the real track and rail vehicle. The results obtained from theoretical analyses were validated with experimental tests carried out on real objects (freight vehicle - test track, freight wagon - test rig). As part of the research, new test track geometry for testing rail vehicles was proposed. The results obtained in this way allowed estimating the conditions threatening the operation of a freight vehicle while running on the test rail infrastructure with different assessment criteria and to compare them.

Keywords:
operational safety, rail vehicle dynamics, derailment, experimental tests, numerical investigations

11.Słowicka A.M., Stone H.A., Ekiel-Jeżewska M.L., Flexible fibers in shear flow approach attracting periodic solutions, PHYSICAL REVIEW E, ISSN: 2470-0045, DOI: 10.1103/PhysRevE.101.023104, Vol.101, No.2, pp.023104-1-14, 2020
Słowicka A.M., Stone H.A., Ekiel-Jeżewska M.L., Flexible fibers in shear flow approach attracting periodic solutions, PHYSICAL REVIEW E, ISSN: 2470-0045, DOI: 10.1103/PhysRevE.101.023104, Vol.101, No.2, pp.023104-1-14, 2020

Abstract:
The three-dimensional dynamics of a single non-Brownian flexible fiber in shear flow is evaluated numerically, in the absence of inertia. A wide range of ratios A of bending to hydrodynamic forces and hundreds of initial configurations are considered. We demonstrate that flexible fibers in shear flow exhibit much more complicated evolution patterns than in the case of extensional flow, where transitions to higher-order modes of characteristic shapes are observed when A exceeds consecutive threshold values. In shear flow, we identify the existence of an attracting steady configuration and different attracting periodic motions that are approached by long-lasting rolling, tumbling, and meandering dynamical modes, respectively. We demonstrate that the final stages of the rolling and tumbling modes are effective Jeffery orbits, with the constant parameter C replaced by an exponential function that either decays or increases in time, respectively, corresponding to a systematic drift of the trajectories. In the limit of C→0, the fiber aligns with the vorticity direction and in the limit of C→∞, the fiber periodically tumbles within the shear plane. For moderate values of A, a three-dimensional meandering periodic motion exists, which corresponds to intermediate values of C. Transient, close to periodic oscillations are also detected in the early stages of the modes.

12.Blachowski B., Tauzowski P., Lógó J., Yield limited optimal topology design of elastoplastic structures, STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION, ISSN: 1615-147X, DOI: 10.1007/s00158-019-02447-9, pp.1-24, 2020
Blachowski B., Tauzowski P., Lógó J., Yield limited optimal topology design of elastoplastic structures, STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION, ISSN: 1615-147X, DOI: 10.1007/s00158-019-02447-9, pp.1-24, 2020

Abstract:
This study is devoted to a novel method for topology optimization of elastoplastic structures subjected to stress constraints. It should be noted that in spite of the classical solutions of the different type of elastoplastic topology problems are more than 70 years old, the integration of the Prandtl-Reuss constitutive equations into the topology optimization process is not very often investigated in the last three decades. In the presented methodology where the classical variational principles of plasticity and the functor-oriented programming technique are applied in topology design, the aim is to find a minimum weight structure which is able to carry a given load, fulfills the allowable stress limit, and is made of a linearly elastic, perfectly plastic material. The optimal structure is found in an iterative way using only a stress intensity distribution and a return mapping algorithm. The method determines representative stresses at every Gaussian point, averages them inside every finite element using the von Mises yield criterion, and removes material proportionally to the stress intensities in individual finite elements. The procedure is repeated until the limit load capacity is exceeded under a given loading. The effectiveness of the methodology is illustrated with three numerical examples. Additionally, different topologies are presented for a purely elastic and an elastoplastic material, respectively. It is also demonstrated that the proposed method is able to find the optimal elastoplastic topology for a problem with a computational mesh of the order of tens of thousands of finite elements.

Keywords:
Topology optimization, Elastoplastic structures, Minimum-weight design, Stress constraints

13.Neisiany R.E., Enayati M.S., Sajkiewicz P., Pahlevanneshan Z., Ramakrishna S., Insight Into the Current Directions in Functionalized Nanocomposite Hydrogels, Frontiers in Materials, ISSN: 2296-8016, DOI: 10.3389/fmats.2020.00025, Vol.7, pp.25-1-8, 2020
Neisiany R.E., Enayati M.S., Sajkiewicz P., Pahlevanneshan Z., Ramakrishna S., Insight Into the Current Directions in Functionalized Nanocomposite Hydrogels, Frontiers in Materials, ISSN: 2296-8016, DOI: 10.3389/fmats.2020.00025, Vol.7, pp.25-1-8, 2020

Abstract:
Since the introduction of tissue engineering as an encouraging method for the repair and regeneration of injured tissue, there have been many attempts by researchers to construct bio-mimetic scaffolds which mimic the native extracellular matrix, with the aim of promoting cell growth, cell proliferation, and restoration of the tissue's native functionality. Among the different materials and methods of scaffold fabrication, one particularly promising class of materials, hydrogels, has been extensively studied, with the inclusion of nano-scaled materials into hydrogels leading to the creation of an exciting new generation of nanocomposites, known as nanocomposite hydrogels. To closely mimic the native tissue behavior, scientists have recently focused on the functionalization of incorporated nanomaterials via chiral biomolecules, with reported results showing great potential. The current article aims to introduce a perspective of nano-scaled cellulose as a promising nanomaterial which can be multi-functionalized for the fabrication of nanocomposite hydrogels with applications in tissue engineering and drug delivery systems. This article also briefly reviews the recently reported literature on nanocomposite hydrogels incorporated with chiral functionalized nanomaterials. Such knowledge paves the path for the development of tailored hydrogels toward practical applications.

Keywords:
scaffold, nanocomposite hydrogels, biodegradable hydrogels, chiral biomolecules, self-healing

14.Krajewski M., Tokarczyk M., Witecka A., Lewińska S., Ślawska-Waniewska A., Płocińska M., Towards Magnetic Bimetallic Wire-Like Nanostructures ‒ Magnetic Field as Growth Parameter, ACTA PHYSICA POLONICA A, ISSN: 0587-4246, DOI: 10.12693/APhysPolA.137.59, Vol.137, No.1, pp.59-61, 2020
15.Makowska K., Kowalewski Z.L., Variation of Barkhausen Noise, Magnetic and Crystal Structure of Ferromagnetic Medium-Carbon Steel after Different Loading Processes, PHYSICS OF METALS AND METALLOGRAPHY, ISSN: 0031-918X, Vol.121, No.2, pp.115-122, 2020
Makowska K., Kowalewski Z.L., Variation of Barkhausen Noise, Magnetic and Crystal Structure of Ferromagnetic Medium-Carbon Steel after Different Loading Processes, PHYSICS OF METALS AND METALLOGRAPHY, ISSN: 0031-918X, Vol.121, No.2, pp.115-122, 2020

Abstract:
The article presents variations of rms Barkhausen noise envelopes in the medium-carbon steel used in automotive and power industry. The material was subjected to different loading processes: monotonic loading at room temperature, and constant loading at elevated temperature. The first one enforced a plastic deformation, whereas the second one a creep. The changes of Barkhausen signal were analysed using microstructural observations including X-ray measurements. In the second part of the paper, the magnetic structure and pinning effect were illustrated by means of the Lorentz microscopy.

Keywords:
Barkhausen noise, magnetic structure, plastic deformation, creep, dislocation density

16.Ostrowski M., Błachowski B., Jankowski Ł., Pisarski D., Modal energy transfer by controlled structural connections, DIAGNOSTYKA, ISSN: 1641-6414, DOI: 10.29354/diag/116692, Vol.21, No.1, pp.61-70, 2020
Ostrowski M., Błachowski B., Jankowski Ł., Pisarski D., Modal energy transfer by controlled structural connections, DIAGNOSTYKA, ISSN: 1641-6414, DOI: 10.29354/diag/116692, Vol.21, No.1, pp.61-70, 2020

Abstract:
This paper describes a semi-active control strategy that allows to transfer the vibration energy from an arbitrarily induced to a selected structural mode. The intended aim of the proposed control strategy is en-ergy harvesting from structural vibrations. Another potential application is related to structural safety. In the paper, a mathematical model is first introduced to describe the phenomenon of vibrational energy transfer, and then, based on this model, an efficient semi-active control strategy is proposed. Finally, some problems related to measurement techniques are discussed. The effectiveness of the proposed methodology is demonstrated in an example of energy transfer between vibrational modes of a three-bar planar frame structure.

Keywords:
vibration energy, modal control, lockable joint, modal coupling

17.Chmielak W.S., Paczkowski R., Papliński P., Piątek Z., Ranachowski P., Ranachowski Z., Śmietanka H., Ocena jakości mikrostruktury warystora poprzez pomiar wyższych harmonicznych w prądzie, PRZEGLĄD ELEKTROTECHNICZNY, ISSN: 0033-2097, DOI: 10.15199/48.2020.01.10, Vol.96, No.1, pp.39-43, 2020
Chmielak W.S., Paczkowski R., Papliński P., Piątek Z., Ranachowski P., Ranachowski Z., Śmietanka H., Ocena jakości mikrostruktury warystora poprzez pomiar wyższych harmonicznych w prądzie, PRZEGLĄD ELEKTROTECHNICZNY, ISSN: 0033-2097, DOI: 10.15199/48.2020.01.10, Vol.96, No.1, pp.39-43, 2020

Abstract:
Celem prezentowanej pracy było znalezienie zależności pomiędzy parametrami mikrostruktury warystorów, a prądem płynącym przez ogranicznik przepięć dla różnych poziomów napięcia. Badania zostały wykonane na losowo wybranej populacji beziskiernikowych ograniczników przepięć w osłonach polimerowych, przeznaczonych do pracy w sieci średniego napięcia. Wykonano pomiary przebiegów referencyjnych dla badanej populacji ograniczników. Przyjęto jako kryterium oceny udział wyższych harmonicznych w przebiegu prądu. Praca stanowi wstęp do szerszego zakresu badań, prowadzonych w ramach wspólnych działań laboratoriów Instytutu Energetyki i Instytutu Podstawowych Problemów Techniki PAN.

Keywords:
beziskiernikowy ogranicznik przepięć, warystor ZnO, mikrostruktura ceramiki, analiza FFT

18.Petryk H., A quasi-extremal energy principle for non-potential problems in rate-independent plasticity, JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS, ISSN: 0022-5096, DOI: 10.1016/j.jmps.2019.103691, Vol.136, pp.103691-1-22, 2020
Petryk H., A quasi-extremal energy principle for non-potential problems in rate-independent plasticity, JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS, ISSN: 0022-5096, DOI: 10.1016/j.jmps.2019.103691, Vol.136, pp.103691-1-22, 2020

Abstract:
The rate-problem of continuing equilibrium is examined for a general class of rate-independent elastoplastic solids, without assuming the normality flow rule or symmetry of the tangent stiffness matrix. Accordingly, the problem addressed is of non-potential type, for which the usual stationarity or minimum principles for a governing potential do not apply. It is shown that the rate-problem can nevertheless be formulated as a quasi-extremal energy principle. It is characterized by explicit dependence of the minimized energy function or functional not only on variables undergoing variations but also, although only in a particular way, on an unknown solution as a parameter. To enable transparent and mathematically simple presentation of the main concept, the energy function is defined in a finite-dimensional setting for a spatially discretized material body with generalized velocities and a number of plastic multipliers as unknowns. If a solution is non-unique then incrementally stable solutions can be selected using the quasi-extremal principle in which the minimized energy function includes the second-order terms. Examples and extensions concern an elastic-plastic continuum obeying a non-associative plastic flow rule, without or with a higher-order gradient term in the loading function. The issue of selection of active slip-systems in a single crystal of a non-symmetric slip-system interaction matrix is also addressed.

Keywords:
Non-associative plasticity, Crystal plasticity, Rate problem, Free energy potential, Dissipation, Internal variables, Thermodynamic basis, Variational formulation, Incremental energy minimization, Non-uniqueness, Path stability, Gradient theory

19.Kalinowski D., Szolc T., Konowrocki R., The new simulation approach of tramway safety against derailment evaluation in term of vehicle dynamics , TRANSBALTICA XI, TRANSBALTICA XI: Transportation Science and Technology, 2019-05-02/05-03, Vilnius (LT), DOI: 10.1007/978-3-030-38666-5_26, pp.245-254, 2020
Kalinowski D., Szolc T., Konowrocki R., The new simulation approach of tramway safety against derailment evaluation in term of vehicle dynamics , TRANSBALTICA XI, TRANSBALTICA XI: Transportation Science and Technology, 2019-05-02/05-03, Vilnius (LT), DOI: 10.1007/978-3-030-38666-5_26, pp.245-254, 2020

Abstract:
The existing European standard EN 14363 covers all necessary tests for different railway vehicles, but it is inadequate for tram vehicles, especially in safety against a derailment examination. Its operational conditions are much different. Trams overcome horizontal curves with much smaller radii than railway vehicles. There is a large diversity in wheel-rail pairing, i.e. almost every public transport operator uses a different wheel profile. In the running gear design much more rubber-metal elements are used in order to ensure a low-floor interior and to keep the kinematic envelope. Apart from standard vehicle configuration, i.e., a carbody on two bogies, in modern tram designs numerous arrangements are applied: wagons with one outer bogie, wagons with one centered bogie, wagons without bogies (sedan) etc., where twisting shims cannot be used to achieve the required twist. The described issues imply that the methodology of safety against derailment described in EN 14363 standard cannot be applied without any modifications. This paper presents a new proposal for a simulation safety against derailment for a vehicle with an arbitrary configuration of wagons and running gears. The numerical analyses have been performed by means of the Simpack Rail software

Keywords:
Safety against derailment, Tram vehicle Numerical, simulation Running dynamics, Simpack rail software

20.Rezaee-Hajidehi M., Tůma K., Stupkiewicz S., Gradient-enhanced thermomechanical 3D model for simulation of transformation patterns in pseudoelastic shape memory alloys, International Journal of Plasticity, ISSN: 0749-6419, DOI: 10.1016/j.ijplas.2019.08.014, pp.1-51, 2019
Rezaee-Hajidehi M., Tůma K., Stupkiewicz S., Gradient-enhanced thermomechanical 3D model for simulation of transformation patterns in pseudoelastic shape memory alloys, International Journal of Plasticity, ISSN: 0749-6419, DOI: 10.1016/j.ijplas.2019.08.014, pp.1-51, 2019

Abstract:
Stress-induced martensitic transformation in polycrystalline NiTi under tension often proceeds through formation and propagation of macroscopic phase transformation fronts, i.e., diffuse interfaces that separate the transformed and untransformed domains. A gradient-enhanced 3D finite-strain model of pseudoelasticity is developed in this work with the aim to describe the related phenomena. The underlying softening response is regularized by enhancing the Helmholtz free energy of a non-gradient model with a gradient term expressed in terms of the martensite volume fraction. To facilitate finite-element implementation, a micromorphic-type regularization is then introduced following the approach developed recently in the 1D small-strain context. The complete evolution problem is formulated within the incremental energy minimization framework, and the resulting non-smooth minimization problem is solved by employing the augmented Lagrangian technique. In order to account for the thermomechanical coupling effects, a general thermomechanical framework, which is consistent with the second law of thermodynamics and considers all related couplings, is also developed. Finite-element simulations of representative 3D problems show that the model is capable of representing the loading-rate effects in a NiTi dog-bone specimen and complex transformation patterns in a NiTi tube under tension. A parametric study is also carried out to investigate the effect of various parameters on the characteristics of the macroscopic transformation front.

Keywords:
Phase transformation, Softening, Strain localization, Micromorphic regularization, Finite-element method

21.Frydrych K., Maj M., Urbański L., Kowalczyk-Gajewska K., Twinning-induced anisotropy of mechanical response of AZ31B extruded rods, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, ISSN: 0921-5093, DOI: 10.1016/j.msea.2019.138610, pp.1-14, 2019
Frydrych K., Maj M., Urbański L., Kowalczyk-Gajewska K., Twinning-induced anisotropy of mechanical response of AZ31B extruded rods, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, ISSN: 0921-5093, DOI: 10.1016/j.msea.2019.138610, pp.1-14, 2019

Abstract:
Texture and twinning-induced anisotropy of the yield stress and hardening of AZ31B extruded rods is investigated. The multidirectional compression tests involving strain path changes are performed in order to: i. assess which slip and twinning systems are active in the polycrystalline sample with a strong texture, ii. analyze the influence of the preliminary deformation upon twin formation, iii. observe the resulting change of the mechanical response. In order to fulfil these goals mechanical testing is supplemented by microstructure analysis. Experimental observations are used to validate the proposed crystal plasticity framework when it is combined with the viscoplastic self-consistent scheme. On the other hand, the results of numerical simulations are used to confirm an advocated interpretation of experimental findings. Finally, the experimental and numerical results are discussed with respect to the theoretical study of slip and twinning activity on the basis of the generalized Schmid criterion. It is concluded that twinning activity influences the mechanical response predominantly by the texture change and to lesser extent by modification of strain hardening due to slip-twin interactions.

Keywords:
Crystal plasticity, Anisotropy, Plastic deformation, Twinning, Hcp

22.Walczak J., Dębska-Vielhaber G., Vielhaber S., Szymański J., Charzyńska A., Duszyński J., Szczepanowska J., Distinction of sporadic and familial forms of ALS based on mitochondrial characteristics, The FASEB Journal, ISSN: 0892-6638, DOI: 10.1096/fj.201801843R, Vol.33, No.3, pp.4388-4403, 2019
Walczak J., Dębska-Vielhaber G., Vielhaber S., Szymański J., Charzyńska A., Duszyński J., Szczepanowska J., Distinction of sporadic and familial forms of ALS based on mitochondrial characteristics, The FASEB Journal, ISSN: 0892-6638, DOI: 10.1096/fj.201801843R, Vol.33, No.3, pp.4388-4403, 2019

Abstract:
Bioenergetic failure, oxidative stress, and changes in mitochondrial morphology are common pathologic hallmarks of amyotrophic lateral sclerosis (ALS) in several cellular and animal models. Disturbed mitochondrial physiology has serious consequences for proper functioning of the cell, leading to the chronic mitochondrial stress. Mitochondria, being in the center of cellular metabolism, play a pivotal role in adaptation to stress conditions. We found that mitochondrial dysfunction and adaptation processes differ in primary fibroblasts derived from patients diagnosed with either sporadic or familial forms of ALS. The evaluation of mitochondrial parameters such as the mitochondrial membrane potential, the oxygen consumption rate, the activity and levels of respiratory chain complexes, and the levels of ATP, reactive oxygen species, and Ca2+ show that the bioenergetic properties of mitochondria are different in sporadic ALS, familial ALS, and control groups. Comparative statistical analysis of the data set (with use of principal component analysis and support vector machine) identifies and distinguishes 3 separate groups despite the small number of investigated cell lines and high variability in measured parameters. These findings could be a first step in development of a new tool for predicting sporadic and familial forms of ALS and could contribute to knowledge of its pathophysiology.—Walczak, J., Dębska-Vielhaber, G., Vielhaber, S., Szymański, J., Charzyńska, A., Duszyński, J., Szczepanowska, J. Distinction of sporadic and familial forms of ALS based on mitochondrial characteristics.

Keywords:
amyotrophic lateral sclerosis, neurodegeneration, primary fibroblasts, PCA

23.Mieldzioć P., Tymkiewicz R., Sołek J., Secomski W., Litniewski J., Fita P., Reaction kinetics of sonochemical oxidation of potassium hexacyanoferrate(II) in aqueous solutions, Ultrasonics Sonochemistry, ISSN: 1350-4177, DOI: 10.1016/j.ultsonch.2019.104912, pp.104912-1-8, 2019
Mieldzioć P., Tymkiewicz R., Sołek J., Secomski W., Litniewski J., Fita P., Reaction kinetics of sonochemical oxidation of potassium hexacyanoferrate(II) in aqueous solutions, Ultrasonics Sonochemistry, ISSN: 1350-4177, DOI: 10.1016/j.ultsonch.2019.104912, pp.104912-1-8, 2019

Abstract:
We studied sonochemical reactions resulting from ultrasonic treatment of potassium hexacyanoferrate(II) in aqueous solutions using a custom-built apparatus working at 536 kHz. We concluded that primary reactions are completely dominated by oxidation of Fe(II) to Fe(III) and did not find any evidences for degradation of cyanide. At the highest concentration used in the present study (0.1 M) we detected formation of pentacyanoaquaferrate(II) complex, which is most probably formed in reactions between hexacyanoferrate(III) anions and hydrogen atoms or hydrated electrons formed in sonochemical processes. We also determined that hydroxyl radicals formation rate in our system, (8.7 ± 1.5)∙10-8 M∙s-1, is relatively high compared to other reported experiments. We attribute this to focusing of the ultrasonic wave in the sample vessel. Finally, we suggest that oxidation rate of hexacyanoferrate(II) anions can be a convenient benchmark of efficiency of sonochemical reactors.

Keywords:
sonochemistry, sonooxidation, sonoreactor, advanced oxidation processes, waste-water treatment

24.Trots I., Tasinkiewicz J., Litniewski J., Estimating the ultrasound attenuation coefficient using complementary Golay codes, Ultrasonics, ISSN: 0041-624X, DOI: 10.1016/j.ultras.2019.106056, pp.106056-1-17, 2019
Trots I., Tasinkiewicz J., Litniewski J., Estimating the ultrasound attenuation coefficient using complementary Golay codes, Ultrasonics, ISSN: 0041-624X, DOI: 10.1016/j.ultras.2019.106056, pp.106056-1-17, 2019

Abstract:
Accurate evaluation of ultrasonic wave attenuation is important in many medical applications of ultrasound. The aim of this work is to present a thorough analysis of the effectiveness of using complementary Golay coded sequences (CGCS) during the evaluation of ultrasound attenuation in tissue-like materials, especially at greater depths or at high attenuation. In order to compare the results of the attenuation measurement with the use of CGCS transmission and a short two sine cycles pulse, ultrasound backscattered from medium with predefined attenuation of 0.3, 0.7 and 2 dB/[MHz×cm] were simulated. Also for the same transmission signals, measurements of ultrasound echoes scattered in the tissue phantom with an attenuation of 0.5 dB/[MHz×cm] were performed. In the case of numerically simulated data, for the CGCS excitation, the maximum depth for which the attenuation was correctly determined increased from 55 mm to 80 mm for the 0.7 dB/[MHz×cm] phantom and from 20 mm to 50 mm for the 2 dB/[MHz×cm] phantom compared to excitation of the transducer with a short two sine cycles pulse. When the measurement data obtained using the tissue phantom was used to estimate the attenuation coefficient, the relative error was determined to be 6% and 16% for the depths of 10 mm and 40 mm for the short two sine cycles pulse excitation, respectively. Corresponding values for CGCS excitation and considered depths were 2% and 4%. The use of CGSC sequence during attenuation measurements increases measurement accuracy and can improve medical diagnostic techniques.

Keywords:
Attenuation, coded excitation, Golay sequences, ultrasound imaging

25.Rinoldi C., Costantini M., Kijeńska-Gawrońska E., Testa S., Fornetti E., Heljak M., Ćwiklińska M., Buda R., Baldi J., Cannata S., Guzowski J., Gargioli C., Khademhosseini A., Święszkowski W., Tendon Tissue Engineering: Effects of Mechanical and Biochemical Stimulation on Stem Cell Alignment on Cell‐Laden Hydrogel Yarns, ADVANCED HEALTHCARE MATERIALS, ISSN: 2192-2659, DOI: 10.1002/adhm.201801218, Vol.8, No.7, pp.1801218-1-10, 2019
Rinoldi C., Costantini M., Kijeńska-Gawrońska E., Testa S., Fornetti E., Heljak M., Ćwiklińska M., Buda R., Baldi J., Cannata S., Guzowski J., Gargioli C., Khademhosseini A., Święszkowski W., Tendon Tissue Engineering: Effects of Mechanical and Biochemical Stimulation on Stem Cell Alignment on Cell‐Laden Hydrogel Yarns, ADVANCED HEALTHCARE MATERIALS, ISSN: 2192-2659, DOI: 10.1002/adhm.201801218, Vol.8, No.7, pp.1801218-1-10, 2019

Abstract:
Fiber-based approaches hold great promise for tendon tissue engineering enabling the possibility of manufacturing aligned hydrogel filaments that can guide collagen fiber orientation, thereby providing a biomimetic micro-environment for cell attachment, orientation, migration, and proliferation. In this study, a 3D system composed of cell-laden, highly aligned hydrogel yarns is designed and obtained via wet spinning in order to reproduce the morphology and structure of tendon fascicles. A bioink composed of alginate and gelatin methacryloyl (GelMA) is optimized for spinning and loaded with human bone morrow mesenchymal stem cells (hBM-MSCs). The produced scaffolds are subjected to mechanical stretching to recapitulate the strains occurring in native tendon tissue. Stem cell differentiation is promoted by addition of bone morphogenetic protein 12 (BMP-12) in the culture medium. The aligned orientation of the fibers combined with mechanical stimulation results in highly preferential longitudinal cell orientation and demonstrates enhanced collagen type I and III expression. Additionally, the combination of biochemical and mechanical stimulations promotes the expression of specific tenogenic markers, signatures of efficient cell differentiation towards tendon. The obtained results suggest that the proposed 3D cell-laden aligned system can be used for engineering of scaffolds for tendon regeneration.

Keywords:
hydrogel fibers, static mechanical stretching, stem cell alignment, tenogenic differentiation, wet spinning

26.Moćko W., Radziejewska J., Analysis of the Application of a Nanosecond Laser Pulse for Dynamic Hardness Tests Under Ultra-High Strain Rates, EXPERIMENTAL MECHANICS, ISSN: 0014-4851, DOI: 10.1007/s11340-019-00471-w, Vol.59, pp.483-487, 2019
Moćko W., Radziejewska J., Analysis of the Application of a Nanosecond Laser Pulse for Dynamic Hardness Tests Under Ultra-High Strain Rates, EXPERIMENTAL MECHANICS, ISSN: 0014-4851, DOI: 10.1007/s11340-019-00471-w, Vol.59, pp.483-487, 2019

Abstract:
Experimental and numerical tests of surface plastic deformation generated under different strain rates were performed. Deformations were introduced by both classical Brinell and laser pulse hardness tests. An Nd:YAG laser with a wavelength of 1064 nm and a laser pulse time length of 10 ns was used to generated a shock wave to induce local plastic deformation on the material surface. The laser pulse induces a repeatable plastic deformation of a surface without thermal effects on the surfaces. Based on imprint geometry, the dynamic hardness of materials was evaluated at a strain rate of the order 107 s-1. Numerical analyses carried out included quasi-static and dynamic Brinell hardness tests and laser pulse interactions with materials. The Rusinek-Klepaczko constitutive model applied in the calculations allows the prediction of the mechanical characteristics at a strain range strain range from 10 to 4 s-1 to 107 s-1. Numerical and experimental results from the surface plastic deformations show close agreement.

Keywords:
Laser pulse, Dynamic hardness, Plastic deformations, Metals

27.Bukowicki M., Ekiel-Jeżewska M.L., Sedimenting pairs of elastic microfilaments, SOFT MATTER, ISSN: 1744-683X, DOI: 10.1039/c9sm01373c, Vol.15, pp.9405-9417, 2019
Bukowicki M., Ekiel-Jeżewska M.L., Sedimenting pairs of elastic microfilaments, SOFT MATTER, ISSN: 1744-683X, DOI: 10.1039/c9sm01373c, Vol.15, pp.9405-9417, 2019

Abstract:
The dynamics of two identical elastic filaments settling under gravity in a viscous fluid in the low Reynolds number regime is investigated numerically. A large family of initial configurations symmetric with respect to a vertical plane is considered, as well as their non-symmetric perturbations. The behaviour of the filaments is primarily governed by the elasto-gravitational number, which depends on the filament's length and flexibility, and the strength of the external force. Flexible filaments usually converge toward horizontal and parallel orientation. We explain this phenomenon and show that it occurs also for curved rigid particles of similar shapes. Once aligned, the two fibres either converge toward a stationary, flexibility-dependent distance, or tend to collide or continuously repel each other. Rigid and straight rods perform periodic motions while settling down. Apart from very stiff particles, the dynamics is robust to non-symmetric perturbations.

28.Rezaee-Hajidehi M., Stupkiewicz S., Phase-field modeling of multivariant martensitic microstructures and size effects in nano-indentation, MECHANICS OF MATERIALS, ISSN: 0167-6636, DOI: 10.1016/j.mechmat.2019.103267, pp.1-32, 2019
Rezaee-Hajidehi M., Stupkiewicz S., Phase-field modeling of multivariant martensitic microstructures and size effects in nano-indentation, MECHANICS OF MATERIALS, ISSN: 0167-6636, DOI: 10.1016/j.mechmat.2019.103267, pp.1-32, 2019

Abstract:
A finite-strain phase-field model is developed for the analysis of multivariant martensitic transformation during nano-indentation. Variational formulation of the complete evolution problem is developed within the incremental energy minimization framework. Computer implementation is performed based on the finite-element method which allows a natural treatment of the finite-strain formulation and of the contact interactions. A detailed computational study of nano-indentation reveals several interesting effects including the pop-in effect associated with nucleation of martensite and the energy-lowering breakdown of the symmetry of microstructure. The effect of the indenter radius is also examined revealing significant size effects governed by the interfacial energy. Keywords: phase-field method, microstructure, shape-memory alloys, nano-indentation, size effects

29.Wojtacki K., Vincent P.G., Suquet P., Moulinec H., Boittin G., A micromechanical model for the secondary creep of elasto-viscoplastic porous materials with two rate-sensitivity exponents: Application to a mixed oxide fuel, INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, ISSN: 0020-7683, DOI: 10.1016/j.ijsolstr.2018.12.026, pp.1-15, 2019
Wojtacki K., Vincent P.G., Suquet P., Moulinec H., Boittin G., A micromechanical model for the secondary creep of elasto-viscoplastic porous materials with two rate-sensitivity exponents: Application to a mixed oxide fuel, INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, ISSN: 0020-7683, DOI: 10.1016/j.ijsolstr.2018.12.026, pp.1-15, 2019

Abstract:
This study deals with the secondary creep of a porous nuclear fuel. This material is composed of an isotropic matrix, weakened by randomly distributed clusters of pores. The viscous strain in the matrix is described by two power-law viscosities corresponding to two different creep mechanisms. The material microstructure is analyzed and appropriate descriptors of its morphology are identified. Representative Volume Elements (RVE's) are generated according to these descriptors. The local fields and overall response of these realizations RVE's are simulated within the framework of periodic homogenization using a full-field computational method based on Fast Fourier Transforms. An analytical model based on appropriate approximations of the effective potential governing the overall response of porous materials under creep is proposed. The accuracy of the model is assessed by comparing its predictions with full-field simulations and the agreement is found to be quite satisfactory.

Keywords:
Porous media, Viscoplasticity, FFT method, Homogenization, Mathematical morphology, Microstructures

30.Chernyshova M., Malinowski K., Czarski T., Kowalska-Strzęciwilk E., Linczuk P., Wojeński A., Krawczyk R.D., Melikhov Y., Advantages of Al based GEM detector aimed at plasma soft−semi hard X-ray radiation imaging, Fusion Engineering and Design, ISSN: 0920-3796, DOI: 10.1016/j.fusengdes.2019.01.153, Vol.146, pp.1039-1042, 2019
Chernyshova M., Malinowski K., Czarski T., Kowalska-Strzęciwilk E., Linczuk P., Wojeński A., Krawczyk R.D., Melikhov Y., Advantages of Al based GEM detector aimed at plasma soft−semi hard X-ray radiation imaging, Fusion Engineering and Design, ISSN: 0920-3796, DOI: 10.1016/j.fusengdes.2019.01.153, Vol.146, pp.1039-1042, 2019

Abstract:
Development of gaseous detectors, more specifically Gas Electron Multiplier (GEM) based detectors, for application at tokamak plasma radiation monitoring/imaging in Soft−Semi Hard X-ray (S−SH) region is an ongoing research activity aiming to deliver valuable information on plasma shape, magnetic configuration, non-axisymmetry phenomena of the plasma, etc. Wide radiation range and brightness of plasma radiation impose some restrictions on choice of materials in the detecting chamber, as their interaction with the incident radiation may disrupt original signals. This work proposes usage of aluminum as GEM foils electrodes for the first time. The detector based on these foils was constructed and examined. The operational characteristics and spectral capabilities of such detector were compared with the ones based on the standard (commonly used) copper GEM foils. The laboratory tests were performed using X-ray tube and 55Fe sources to examine detectors’ capabilities in energy-resolved imaging. Additionally, simulations of origin and number of the generated electrons, which determine the detector signal, were performed for Al and Cu GEM foils for a wide energy range of incident photons. The experimental and modelling data demonstrated that Cu based GEM detector produces higher parasitic signal than Al one necessitating total elimination of copper from detector’s chamber.

Keywords:
Nuclear instruments for hot plasma diagnostics, X-ray detectors, SXR imaging, Electron multipliers (gas), Micropattern gaseous detectors, Aluminum GEM foils

31.Kielbik P., Kaszewski J., Dominiak B., Damentko M., Serafińska I., Rosowska J., Gralak M.A., Krajewski M., Witkowski B.S., Gajewski Z., Godlewski M., Godlewski M.M., Preliminary Studies on Biodegradable Zinc Oxide Nanoparticles Doped with Fe as a Potential Form of Iron Delivery to the Living Organism, Nanoscale Research Letters, ISSN: 1556-276X, DOI: 10.1186/s11671-019-3217-2, Vol.14, pp.373-1-13, 2019
Kielbik P., Kaszewski J., Dominiak B., Damentko M., Serafińska I., Rosowska J., Gralak M.A., Krajewski M., Witkowski B.S., Gajewski Z., Godlewski M., Godlewski M.M., Preliminary Studies on Biodegradable Zinc Oxide Nanoparticles Doped with Fe as a Potential Form of Iron Delivery to the Living Organism, Nanoscale Research Letters, ISSN: 1556-276X, DOI: 10.1186/s11671-019-3217-2, Vol.14, pp.373-1-13, 2019

Abstract:
Iron is the crucial element for living organisms and its deficiency is described as the most common nutritional disorder all over the world. Nowadays, more effective and safe iron supplementation strategies for both humans and animals become one of the most important challenges in the therapy of nutritional deficiencies. Our previous in vivo studies confirmed safety and biodegradability of in-house manufactured zinc oxide-based nanoparticles and their rapid distribution to majority of organs and tissues in the body. In vitro examinations performed on Caco-2 cell line, a model of epithelial cells of the gastrointestinal tract, revealed a low toxicity of studied nanomaterials. In the current study, we investigated biodegradable zinc oxide nanoparticles doped with Fe(III) as a perspective supplementation strategy for iron deficiency. Biodegradable ZnO:Fe nanoparticles were intra-gastrically administered to adult mice and following 24 h, animals were sacrificed with collection of internal organs for further analyses. The iron concentration measured with atomic absorption spectrometry and histological staining (Perl’s method) showed a rapid distribution of iron-doped nanoparticles to tissues specifically related with iron homeostasis. Accumulation of iron was also visible within hepatocytes and around blood vessels within the spleen, which might indicate the transfer of Fe-doped nanoparticles from the bloodstream into the tissue. Reassuming, preliminary results obtained in the current study suggest that biodegradable ZnO nanoparticles doped with Fe might be a good carriers of exogenous iron in the living body. Therefore, subsequent investigations focus on determination an exact mechanisms related with an iron deposition in the tissue and influence of nanoparticle carriers on iron metabolism are required.

Keywords:
ZnO:Fe, Nanoparticles, Iron deficiency, Iron delivery, Iron doping

32.Balevicius R., Mróz Z., Relative Transverse Slip and Sliding of Two Spherical Grains in Contact, JOURNAL OF ENGINEERING MECHANICS-ASCE, ISSN: 0733-9399, DOI: 10.1061/(ASCE)EM.1943-7889.0001587, Vol.145, No.4, pp.04019012-1-9, 2019
Balevicius R., Mróz Z., Relative Transverse Slip and Sliding of Two Spherical Grains in Contact, JOURNAL OF ENGINEERING MECHANICS-ASCE, ISSN: 0733-9399, DOI: 10.1061/(ASCE)EM.1943-7889.0001587, Vol.145, No.4, pp.04019012-1-9, 2019

Abstract:
The analytical models of two spherical grains contact interactions, typical for several classes of slip and sliding regimes in the experimental testing, are proposed. They analyze the cases for coupling or decoupling the frictional microslip and sliding displacements during the kinematically induced sphere translation along a straight trajectory or the force-induced motion from the initially activated contact zone under constant vertical loading. In the slip mode, the evolution of sphere center horizontal displacement obeys the Mindlin-Deresiewicz theory rules either for the force or kinematically induced transverse motions of the sphere. In the frictional sliding mode, it is demonstrated that for the kinematically induced transverse motion of the sphere, the contact tractions are fully governed by the coupled evolution of slip and sliding displacements. When the account for contact slip velocity and the rate of contact plane rotation is made, then the coupling of slip and sliding modes theoretically results in a simple scaling multiplier imposed on the overlap resulted from the sliding mode. It generates a driving force fluctuation and affects the evolution of contact tractions. For transverse sliding of the sphere under constant vertical load and driving force, the contact tractions are essentially governed by the conditions of static equilibrium and are independent of the displacements generated in the slip mode. In this case, the slip displacement provides only the additive term to the sliding displacement of the sphere center, not affecting contact tractions.

Keywords:
Sphere–sphere contact, Frictional slip and sliding, Coulomb friction, Displacement and mixed force-displacement control, Reciprocal motion

33.Marzec I., Tejchman J., Mróz Z., Numerical analysis of size effect in RC beams scaled along height or length using elasto-plastic-damage model enhanced by non-local softening, FINITE ELEMENTS IN ANALYSIS AND DESIGN, ISSN: 0168-874X, DOI: 10.1016/j.finel.2019.01.007, Vol.157, pp.1-20, 2019
Marzec I., Tejchman J., Mróz Z., Numerical analysis of size effect in RC beams scaled along height or length using elasto-plastic-damage model enhanced by non-local softening, FINITE ELEMENTS IN ANALYSIS AND DESIGN, ISSN: 0168-874X, DOI: 10.1016/j.finel.2019.01.007, Vol.157, pp.1-20, 2019

Abstract:
Numerical simulation results of laboratory tests on reinforced concrete beams subjected to four-point bending for a separate variation of the height and length were presented. Due to the lack of a geometrical similarity, two major failure mechanisms were observed: flexural failure mechanism with plastic yielding of reinforcement and shear failure mechanism with two different modes: brittle diagonal tension and brittle diagonal shear-compression. The shear strength increased with increasing effective height and decreased with increasing shear span-effective height ratio. In simulations, the finite element method was used, based on a coupled elasto-plastic-damage constitutive model for concrete under plane stress conditions. The constitutive model was enhanced by integral-type non-locality in the softening regime to yield mesh-independent results. The bond-slip law was assumed between concrete and reinforcement. Two-dimensional numerical calculations under plane stress conditions satisfactorily reproduced both experimental shear strengths and failure mechanisms with one set of input parameters. In addition, the effect of different material constants on strength and fracture was comprehensively studied. Advantages and shortcomings of the numerical approach were discussed.

Keywords:
Size effect, Finite element method, Elasto-plasticity, Damage mechanics, Reinforced concrete, Non-local theory

34.Paczelt I., Mróz Z., Optimized punch contact action related to control of local structure displacement, STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION, ISSN: 1615-147X, DOI: 10.1007/s00158-019-02300-z, Vol.60, No.5, pp.1921-1936, 2019
Paczelt I., Mróz Z., Optimized punch contact action related to control of local structure displacement, STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION, ISSN: 1615-147X, DOI: 10.1007/s00158-019-02300-z, Vol.60, No.5, pp.1921-1936, 2019

Abstract:
For a structure under service loads, there is a need to induce precise control of a local displacement by additional punch loading. Such problem exists in design of robot grippers or agricultural tools used in mechanical processing. The punch interaction is assumed to be executed by a discrete set of pins or by a continuously distributed contact pressure. The optimal contact force or pressure distribution and contact shape are specified for both discrete and continuous punch action. Several boundary support conditions are discussed, and their effects on punch action are presented.

Keywords:
Contact problem, Displacement control, Optimal pressure distribution, Optimal contact shape

35.Tabin J., Skoczeń B., Bielski J., Discontinuous plastic flow coupled with strain induced fcc–bcc phase transformation at extremely low temperatures, Mechanics od Materials, ISSN: 0167-6636, DOI: 10.1016/j.mechmat.2018.10.007, Vol.129, pp.23-40, 2019
Tabin J., Skoczeń B., Bielski J., Discontinuous plastic flow coupled with strain induced fcc–bcc phase transformation at extremely low temperatures, Mechanics od Materials, ISSN: 0167-6636, DOI: 10.1016/j.mechmat.2018.10.007, Vol.129, pp.23-40, 2019

Abstract:
A popular class of materials massively used at cryogenic temperatures comprises the stainless steels of different grades, such as 304, 304L, 316, 316Ti, 316L, 316LN etc. Such materials are metastable at extremely low temperatures, and usually undergo plastic strain induced phase transformation. In addition, these materials applied in the proximity of absolute zero exhibit the so-called discontinuous (intermittent, serrated) plastic flow (DPF). It consists in frequent, abrupt drops of stress against strain, characterized by increasing amplitude of the stress oscillations. Strong coupling between both phenomena: DPF and phase transformation is observed. Recent experiments performed by means of stainless steel samples tested in liquid helium (4.2 K) clearly indicate strong strain localization during DPF, in the form of shear bands propagating along the sample. However, as soon as the phase transformation process takes place, the motion of shear bands is hindered by formation of secondary phase. A physically based constitutive model developed in the present paper reflects coupling between the discontinuous plastic flow and the plastic strain induced phase transformation in the temperature range 0–T1. The model involves nonlinear mixed hardening, that occurs during the 2nd stage of each serration (stress–strain oscillation). The hardening is based on two mechanisms: interaction of dislocations with the inclusions of secondary phase, evolution of tangent stiffness operator due to changing proportions between the primary and the secondary phases. Nonlinear hardening strongly increases the stress level during each serration, which affects production of the internal lattice barriers, and the amount of the accumulated plastic strain. This, in turn, affects intensity of the phase transformation (full coupling). The constitutive model and its numerical version allow to reproduce the observed serrations, which is crucial for its application in the design of components operating at extremely low temperatures.

Keywords:
Multiscale constitutive model, Discontinuous plastic flow, Strain induced phase transformation, Cryogenic temperatures

36.Denis P., Wrzecionek M., Gadomska‐Gajadhur A., Sajkiewicz P., Poly(Glycerol Sebacate)–Poly(l-Lactide) Nonwovens. Towards Attractive Electrospun Material for Tissue Engineering, Polymers, ISSN: 2073-4360, DOI: 10.3390/polym11122113, Vol.11, pp.2113-1-30, 2019
Denis P., Wrzecionek M., Gadomska‐Gajadhur A., Sajkiewicz P., Poly(Glycerol Sebacate)–Poly(l-Lactide) Nonwovens. Towards Attractive Electrospun Material for Tissue Engineering, Polymers, ISSN: 2073-4360, DOI: 10.3390/polym11122113, Vol.11, pp.2113-1-30, 2019

Abstract:
Two types of poly(glycerol sebacate) (PGS) prepolymers were synthesized and electrospun with poly(l-lactic acid) (PLA), resulting in bicomponent nonwovens. The obtained materials were pre-heated in a vacuum, at different times, to crosslink PGS and investigate morphological and structural dependencies in that polymeric, electrospun system. As both PGS and PLA are sensitive to pre-heating (crosslinking) conditions, research concerns both components. More interest is focused on the properties of PGS, considering further research for mechanical properties and subsequent experiments with PGS synthesis. Electrospinning of PGS blended with PLA does not bring difficulties, but obtaining elastomeric properties of nonwovens is problematic. Even though PGS has many potential advantages over other polyesters when soft tissue engineering is considered, its full utilization via the electrospinning process is much harder in practice. Further investigations are ongoing, especially with the promising PGS prepolymer with a higher esterification degree and its variations.

Keywords:
electrospinning, degradable polymers, synthesis, structure, crosslinking

37.Rojek J., Madan N., Nosewicz S., Micro–Macro Relationships in the Simulation of Wave Propagation Phenomenon Using the Discrete Element Method, Materials, ISSN: 1996-1944, DOI: 10.3390/ma12244241, Vol.12, No.24, pp.4241-1-22, 2019
Rojek J., Madan N., Nosewicz S., Micro–Macro Relationships in the Simulation of Wave Propagation Phenomenon Using the Discrete Element Method, Materials, ISSN: 1996-1944, DOI: 10.3390/ma12244241, Vol.12, No.24, pp.4241-1-22, 2019

Abstract:
The present work is aimed to investigate the capability of the discrete element method (DEM) to model properly wave propagation in solid materials, with special focus on the determination of elastic properties through wave velocities. Reference micro–macro relationships for elastic constitutive parameters have been based on the kinematic hypothesis as well as obtained numerically by simulation of a quasistatic uniaxial compression test. The validity of these relationships in the dynamic analysis of the wave propagation has been checked. Propagation of the longitudinal and shear wave pulse in rectangular sample discretized with discs has been analysed. Wave propagation velocities obtained in the analysis have been used to determine elastic properties. Elastic properties obtained in the dynamic analysis have been compared with those determined by simulation of the quasistatic compression test.

Keywords:
discrete element method; wave propagation; elastic properties; micro–macro relationships

38.Wood P., Libura T., Kowalewski Z.L., Williams G., Serjouei A., Influences of Horizontal and Vertical Build Orientations and Post-Fabrication Processes on the Fatigue Behavior of Stainless Steel 316L Produced by Selective Laser Melting, Materials, ISSN: 1996-1944, DOI: 10.3390/ma12244203, Vol.12, No.24, pp.4203-1-19, 2019
Wood P., Libura T., Kowalewski Z.L., Williams G., Serjouei A., Influences of Horizontal and Vertical Build Orientations and Post-Fabrication Processes on the Fatigue Behavior of Stainless Steel 316L Produced by Selective Laser Melting, Materials, ISSN: 1996-1944, DOI: 10.3390/ma12244203, Vol.12, No.24, pp.4203-1-19, 2019

Abstract:
In this paper, the influences of build orientation and post-fabrication processes, including stress-relief, machining, and shot-peening, on the fatigue behavior of stainless steel (SS) 316L manufactured using selective laser melting (SLM) are studied. It was found that horizontally-built (XY) and machined (M) test pieces, which had not been previously studied in the literature, in both stress-relieved (SR) or non-stress-relieved (NSR) conditions show superior fatigue behavior compared to vertically-built (ZX) and conventionally-manufactured SS 316L. The XY, M, and SR (XY-M-SR) test pieces displayed fatigue behavior similar to the XY-M-NSR test pieces, implying that SR does not have a considerable effect on the fatigue behavior of XY and M test pieces. ZX-M-SR test pieces, due to their considerably lower ductility, exhibited significantly larger scatter and a lower fatigue strength compared to ZX-M-NSR samples. Shot-peening (SP) displayed a positive effect on improving the fatigue behavior of the ZX-NSR test pieces due to a compressive stress of 58 MPa induced on the surface of the test pieces. Fractography of the tensile and fatigue test pieces revealed a deeper understanding of the relationships between the process parameters, microstructure, and mechanical properties for SS 316L produced by laser systems. For example, fish-eye fracture pattern or spherical stair features were not previously observed or explained for cyclically-loaded SLM-printed parts in the literature. This study provides comprehensive insight into the anisotropy of the static and fatigue properties of SLM-printed parts, as well as the pre- and post-fabrication parameters that can be employed to improve the fatigue behavior of steel alloys manufactured using laser systems

Keywords:
selective laser melting, stainless steel 316L, fatigue, defect, fracture

39.Martinez M., Cooper C.D., Poma Bernaola A., Guzman H.V., Free Energies of the Disassembly of Viral Capsids from a Multiscale Molecular Simulation Approach, Journal of Chemical Information and Modeling, ISSN: 1549-9596, DOI: 10.1021/acs.jcim.9b00883, Vol.0, pp.1-24, 2019
Martinez M., Cooper C.D., Poma Bernaola A., Guzman H.V., Free Energies of the Disassembly of Viral Capsids from a Multiscale Molecular Simulation Approach, Journal of Chemical Information and Modeling, ISSN: 1549-9596, DOI: 10.1021/acs.jcim.9b00883, Vol.0, pp.1-24, 2019

Abstract:
Molecular simulations of large biological systems, such as viral capsids, remains a challenging task in soft matter research. On one hand, coarse-grained (CG) models attempt to make feasible the description of the entire viral capsid disassembly. On the other hand, a permanent development of novel molecular dynamics (MD) simulation approaches like enhance sampling methods attempt to overcome the large time scales required for such simulations. Those methods have a potential for delivering molecular structures and properties of biological systems. Nonetheless, exploring the process on how a viral capsid disassembles by all-atom MD simulations has been rarely attempted. Here, we propose a methodology to analyze the disassembly process of viral capsids from a free energy perspective, through an efficient combination of dynamics using coarse-grained models and Poisson-Boltzmann simulations. In particular, we look at the effect of $pH$ and charge of the genetic material inside the capsid, and compute the free energy of a disassembly trajectory precalculated using CG simulations with the SIRAH force field. We used our multiscale approach on the Triatoma virus (TrV) as a test case, and find that even though an alkaline environment enhances the stability of the capsid, the resulting deprotonation of the genetic material generates a Coulomb-type electrostatic repulsion that triggers disassembly.

40.Rinoldi C., Fallahi A., Yazdi I.K., Paras J.C., Kijeńska-Gawrońska E., Trujillo-de Santiago G., Tuoheti A., Demarchi D., Annabi N., Khademhosseini A., Święszkowski W., Tamayol A., Mechanical and Biochemical Stimulation of 3D Multilayered Scaffolds for Tendon Tissue Engineering, ACS BIOMATERIALS SCIENCE & ENGINEERING, ISSN: 2373-9878, DOI: 10.1021/acsbiomaterials.8b01647, Vol.5, No.6, pp.2953-2964, 2019
Rinoldi C., Fallahi A., Yazdi I.K., Paras J.C., Kijeńska-Gawrońska E., Trujillo-de Santiago G., Tuoheti A., Demarchi D., Annabi N., Khademhosseini A., Święszkowski W., Tamayol A., Mechanical and Biochemical Stimulation of 3D Multilayered Scaffolds for Tendon Tissue Engineering, ACS BIOMATERIALS SCIENCE & ENGINEERING, ISSN: 2373-9878, DOI: 10.1021/acsbiomaterials.8b01647, Vol.5, No.6, pp.2953-2964, 2019

Abstract:
Tendon injuries are frequent and occur in the elderly, young, and athletic populations. The inadequate number of donors combined with many challenges associated with autografts, allografts, xenografts, and prosthetic devices have added to the value of engineering biological substitutes, which can be implanted to repair the damaged tendons. Electrospun scaffolds have the potential to mimic the native tissue structure along with desired mechanical properties and, thus, have attracted noticeable attention. In order to improve the biological responses of these fibrous structures, we designed and fabricated 3D multilayered composite scaffolds, where an electrospun nanofibrous substrate was coated with a thin layer of cell-laden hydrogel. The whole construct composition was optimized to achieve adequate mechanical and physical properties as well as cell viability and proliferation. Mesenchymal stem cells (MSCs) were differentiated by the addition of bone morphogenetic protein 12 (BMP-12). To mimic the natural function of tendons, the cell-laden scaffolds were mechanically stimulated using a custom-built bioreactor. The synergistic effect of mechanical and biochemical stimulation was observed in terms of enhanced cell viability, proliferation, alignment, and tenogenic differentiation. The results suggested that the proposed constructs can be used for engineering functional tendons.

Keywords:
tendon tissue engineering, composite scaffolds, nanofibrous materials, mechanical stimulation, stem cell differentiation

41.Fallahi A., Yazdi I., Serex L., Lasha E., Faramarzi N., Tarlan F., Avci H., Almeida R., Sharifi F., Rinoldi C., Gomes M.E., Shin S.R., Khademhosseini A., Akbari M., Tamayol A., Customizable composite fibers for engineering skeletal muscle models, ACS BIOMATERIALS SCIENCE & ENGINEERING, ISSN: 2373-9878, DOI: 10.1021/acsbiomaterials.9b00992, pp.1-37, 2019
Fallahi A., Yazdi I., Serex L., Lasha E., Faramarzi N., Tarlan F., Avci H., Almeida R., Sharifi F., Rinoldi C., Gomes M.E., Shin S.R., Khademhosseini A., Akbari M., Tamayol A., Customizable composite fibers for engineering skeletal muscle models, ACS BIOMATERIALS SCIENCE & ENGINEERING, ISSN: 2373-9878, DOI: 10.1021/acsbiomaterials.9b00992, pp.1-37, 2019

Abstract:
Engineering tissue-like scaffolds that can mimic the microstructure, architecture, topology, and mechanical properties of native tissues while offering an excellent environment for cellular growth has remained an unmet need. To address these challenges, multi-compartment composite fibers are fabricated. These fibers can be assembled through textile processes to tailor tissue-level mechanical and electrical properties independent of cellular level components. Textile technologies also allow controlling the distribution of different cell types and microstructure of fabricated constructs and directing cellular growth within 3D microenvironment. Here, we engineered composite fibers from biocompatible cores and biologically relevant hydrogel sheaths. The fibers are mechanically robust to be assembled using textile processes and could support adhesion, proliferation and maturation of cell populations important for engineering of skeletal muscles. We also demonstrated that the changes in the electrical conductivity of the multi-compartment fibers could significantly enhance myogenesis in vitro.

42.Sondej T., Sieczkowski K., Olszewski R., Dobrowolski A., Simultaneous multi-site measurement system for the assessment of pulse wave delays, Biocybernetics and Biomedical Engineering, ISSN: 0208-5216, DOI: 10.1016/j.bbe.2019.01.001, Vol.39, No.2, pp.488-502, 2019
Sondej T., Sieczkowski K., Olszewski R., Dobrowolski A., Simultaneous multi-site measurement system for the assessment of pulse wave delays, Biocybernetics and Biomedical Engineering, ISSN: 0208-5216, DOI: 10.1016/j.bbe.2019.01.001, Vol.39, No.2, pp.488-502, 2019

Abstract:
A precise, multi-track system for the simultaneous, real-time measurement of electrocardiographic (ECG) and many photopletysmographic (PPG) signals is described. This system allows the calculation of pulse wave delay parameters such as pulse arrival time (PAT) and pulse transit time (PTT). The measurement system was built on a custom, real-time embedded system with multiple specific analogue-front-end devices. Signals were recorded on-line and data were processed off-line in the Matlab software. Testing of human subjects was carried out on a group of 16 volunteers. The system was capable of taking a measurement of one 24-bit ECG and eight 22-bit PPG tracks with high precision (input-referred noise 1.4 μV for ECG and about 20 pA for PPG). All signals are sampled simultaneously (phase shift between ECG and PPG is only 1.5 ms for 250 Hz frequency sampling). Significant differences in pulse wave delays were found for the 16 subjects studied (e.g. about 100 ms for PAT on a right toe, 40 ms for differential PAT on left-right toes and about 100 ms for PTT calculated for forehead-right toe pulse wave). The proposed system provides a simultaneous and continuous evaluation of pulse wave delays for the entire arterial bed. The proposed measurement methods are comfortable and can be used for a long time. Simultaneous measurements of pulse wave delays at various sites increase the reliability of measurement and create new possibilities for medical diagnosis.

Keywords:
Biomedical monitoring, Cardiovascular diseases , Pulse arrival time, Pulse transit time, Pulse wave delay, Simultaneous measurement

43.Krajewski M., Tokarczyk M., Stefaniuk T., Lewińska S., Ślawska-Waniewska A., Thermal Treatment of Chains of Amorphous Fe1–xCox Nanoparticles Made by Magnetic-Field-Induced Coreduction Reaction, IEEE Magnetics Letters, ISSN: 1949-307X, DOI: 10.1109/LMAG.2019.2950644, Vol.10, pp.6108405-1-5, 2019
Krajewski M., Tokarczyk M., Stefaniuk T., Lewińska S., Ślawska-Waniewska A., Thermal Treatment of Chains of Amorphous Fe1–xCox Nanoparticles Made by Magnetic-Field-Induced Coreduction Reaction, IEEE Magnetics Letters, ISSN: 1949-307X, DOI: 10.1109/LMAG.2019.2950644, Vol.10, pp.6108405-1-5, 2019

Abstract:
The thermal treatment of chains composed of amorphous Fe 1–x Co x nanoparticles in two different oxygen atmospheres was studied. The nanostructures were manufactured using a magnetic-field-induced coreduction reaction, in which the precursor solutions containing 1:3 and 3:1 proportions of Fe 2+ and Co 2+ ions were reduced with sodium borohydride. The as-prepared nanochains were then heated for 30 min at 400 and 500 °C in dry air or argon containing about 1% oxygen. These processes led to their oxidation, and, as a result, the thermally treated Fe 1–x Co x nanochains were transformed into cobalt ferrite. Heating at 500 °C in the air-containing atmosphere caused the nanomaterials to lose their nanochain structures. In accordance to room-temperature magnetic measurements, the as-prepared and thermally treated Fe 1–x Co x nanochains were ferromagnetic. The highest saturation magnetization ( M S ) was measured for the Fe 1–x Co x nanochains treated at 400 °C in dry air (105 A·m 2 /kg and 154 A·m 2 /kg for Fe 0.25 Co 0.75 and Fe 0.75 Co 0.25 , respectively), whereas the lowest M S was found for the Fe 0.25 Co 0.75 heated at 500 °C in dry air (17 A·m 2 /kg) and the Fe 0.75 Co 0.25 heated at 500 °C in argon (16 A·m 2 /kg).

Keywords:
Nanomagnetics, FeCo nanochains, magnetic-field-induced synthesis, thermal treatment

44.Malińska D., Więckowski M.R., Michalska B., Drabik K., Prill M., Patalas-Krawczyk P., Walczak J., Szymański J., Mathis C., Van der Toorn M., Luettich K., Hoeng J., Peitsch M.C., Duszyński J., Szczepanowska J., Mitochondria as a possible target for nicotine action, Journal of Bioenergetics and Biomembranes, ISSN: 0145-479X, DOI: 10.1007/s10863-019-09800-z, Vol.51, No.4, pp.259-276, 2019
Malińska D., Więckowski M.R., Michalska B., Drabik K., Prill M., Patalas-Krawczyk P., Walczak J., Szymański J., Mathis C., Van der Toorn M., Luettich K., Hoeng J., Peitsch M.C., Duszyński J., Szczepanowska J., Mitochondria as a possible target for nicotine action, Journal of Bioenergetics and Biomembranes, ISSN: 0145-479X, DOI: 10.1007/s10863-019-09800-z, Vol.51, No.4, pp.259-276, 2019

Abstract:
Mitochondria are multifunctional and dynamic organelles deeply integrated into cellular physiology and metabolism. Disturbances in mitochondrial function are involved in several disorders such as neurodegeneration, cardiovascular diseases, metabolic diseases, and also in the aging process. Nicotine is a natural alkaloid present in the tobacco plant which has been well studied as a constituent of cigarette smoke. It has also been reported to influence mitochondrial function both in vitro and in vivo. This review presents a comprehensive overview of the present knowledge of nicotine action on mitochondrial function. Observed effects of nicotine exposure on the mitochondrial respiratory chain, oxidative stress, calcium homeostasis, mitochondrial dynamics, biogenesis, and mitophagy are discussed, considering the context of the experimental design. The potential action of nicotine on cellular adaptation and cell survival is also examined through its interaction with mitochondria. Although a large number of studies have demonstrated the impact of nicotine on various mitochondrial activities, elucidating its mechanism of action requires further investigation.

Keywords:
adaptation, mitochondria, nicotine, oxidative stress

45.Demchenko I.N., Ratajczak R., Melikhov Y., Konstantynov P., Guziewicz E., Valence band of ZnO:Yb probed by resonant photoemission spectroscopy, Materials Science in Semiconductor Processing, ISSN: 1369-8001, DOI: 10.1016/j.mssp.2018.11.037, Vol.91, pp.306-309, 2019
Demchenko I.N., Ratajczak R., Melikhov Y., Konstantynov P., Guziewicz E., Valence band of ZnO:Yb probed by resonant photoemission spectroscopy, Materials Science in Semiconductor Processing, ISSN: 1369-8001, DOI: 10.1016/j.mssp.2018.11.037, Vol.91, pp.306-309, 2019

Abstract:
Resonant photoemission spectroscopy (RPES), which is a useful tool for extracting photoemission response of the localized Rare Earth (RE) impurity levels from the host electronic band structure, was used to study ZnO:Yb films. The resonant enhancement of the photoemission signal at binding energy around 7.5 and 11.7 eV was observed when photon energy was tuned to the Yb 4d-4f absorption threshold (182 eV). It was found that the 4f and the valence band (VB) maximum binding energies do not depend on the Yb dose, suggesting that the measurement of only one concentration is sufficient to determine the binding energies of the Yb 4f in the examined system. Subsequent annealing did not change the arrangements of implanted ytterbium atoms in host matrix: the majority of them remain in 3 + state having pseudo-octahedral local arrangement similar to Yb2O3.

46.Lanzi M., Salatelli E., Marinelli M., Pierini F., Effect of Photocrosslinking of D‐A Thiophene Copolymers on the Performance of Single‐Material Solar Cells, Macromolecular Chemistry and Physics, ISSN: 1022-1352, DOI: 10.1002/macp.201900433, pp.1900433-1-12, 2019
Lanzi M., Salatelli E., Marinelli M., Pierini F., Effect of Photocrosslinking of D‐A Thiophene Copolymers on the Performance of Single‐Material Solar Cells, Macromolecular Chemistry and Physics, ISSN: 1022-1352, DOI: 10.1002/macp.201900433, pp.1900433-1-12, 2019

Abstract:
Side‐chain C60‐fullerene functionalized alkylthiophene copolymers with different regioregularity and fullerene content are successfully synthesized using a simple and straightforward post‐polymerization functionalization procedure based on a Grignard coupling reaction. The products are employed as single materials in photoactive layers of organic photovoltaic solar cells. The use of double‐cable polymers allows an enhanced control on the nanomorphology of the active blend, reducing the phase‐segregation phenomena as well as the macroscale separation between the electron acceptor and donor components. With the insertion of a thin layer of gold nanoparticles between buffer and active layer of the cells, a conversion efficiency of 5.68% is obtained. Moreover, an increased stability over time is achieved when the copolymers are photocrosslinked immediately after the annealing procedure, leading to acceptable efficiencies even after 80 h of accelerated ageing, a key feature for widespread applicability of the prepared devices.

Keywords:
conjugated polymers, fullerenes, functionalization of polymers, metathesis

47.Stańczak M., Fras T., Blanc L., Pawłowski P., Rusinek A., Blast-Induced Compression of a Thin-Walled Aluminum Honeycomb Structure—Experiment and Modeling, Metals, ISSN: 2075-4701, DOI: 10.3390/met9121350, Vol.9, No.12, pp.1350-1-24, 2019
Stańczak M., Fras T., Blanc L., Pawłowski P., Rusinek A., Blast-Induced Compression of a Thin-Walled Aluminum Honeycomb Structure—Experiment and Modeling, Metals, ISSN: 2075-4701, DOI: 10.3390/met9121350, Vol.9, No.12, pp.1350-1-24, 2019

Abstract:
The presented discussion concerns the behavior of a thin-walled hexagonal aluminum honeycomb structure subjected to blast loading. The shock wave affecting the structure is generated by detonation of the C4 charge in an explosive-driven shock tube (EDST). The EDST set-up is an instrumented device that makes it possible to study blast effects in more stable and repeatable conditions than those obtained in a free-air detonation. The formation of folds characteristic of a honeycomb deformation in the axial compression distributes the initial loading over a time period, which is considered as an efficient method of energy dissipation. The test configuration is modeled in the Ls-Dyna explicit code, which enables analysis of the mechanisms of energy absorption that accompanies structural deformation under a blast loading. The conclusions reached in the performed experimental and numerical investigation can be applied to the modeling and optimization of cellular structures used to mitigate blast loadings.

Keywords:
thin-walled hexagonal aluminum honeycomb; dynamic compression; blast energy absorption; EDST; numerical simulation of blast effects

48.Braga L.S., Azevedo Moreira R., Soares Leal D.H., Ramalho T.C., Quantification of molecular orbitals based on projection operators: Methodological development and applications to basicity prediction of organic compounds in the gas phase, Chemical Physics Letters, ISSN: 0009-2614, DOI: 10.1016/j.cplett.2019.04.023, Vol.726, pp.87-92, 2019
Braga L.S., Azevedo Moreira R., Soares Leal D.H., Ramalho T.C., Quantification of molecular orbitals based on projection operators: Methodological development and applications to basicity prediction of organic compounds in the gas phase, Chemical Physics Letters, ISSN: 0009-2614, DOI: 10.1016/j.cplett.2019.04.023, Vol.726, pp.87-92, 2019

Abstract:
Basicity is an important parameter with impact on biological systems and technological problems. The HOMO-LUMO and FERMO theoretical approaches can describe the acid-base behavior of compounds as amines, carboxylic acids and alcohols. In this work, a method was developed using the localization degree ГFERMO parameter based on projection operators to quantify the localization of molecular orbitals. This new method was employed for the analysis of the protonation reaction of 30 organic compounds. The quantitative data from our findings were able to reproduce experimental data, pointing out that the FERMO approach could better describe the acid-base behavior of the investigated compounds.

Keywords:
Molecular orbital, HOMO-LUMO, FERMO, Acid-base behaviour, Localization degree, ГFERMO

49.Ciupak M., Misztal-Faraj B., Pęcherski R.B., Silne efekty entropowe orientacji molekularnej w kinetyce krystalizacji polimerów, Przemysł Chemiczny, ISSN: 0033-2496, DOI: 10.15199/62.2019.11.13, Vol.98/11, pp.1760-1764, 2019
Ciupak M., Misztal-Faraj B., Pęcherski R.B., Silne efekty entropowe orientacji molekularnej w kinetyce krystalizacji polimerów, Przemysł Chemiczny, ISSN: 0033-2496, DOI: 10.15199/62.2019.11.13, Vol.98/11, pp.1760-1764, 2019

Abstract:
Obliczono i przedyskutowano wpływ orientacji molekularnej oraz temperatury na szybkość nukleacji i wzrostu kryształów ze wskazaniem na rolę entropii w kinetyce krystalizacji polimerów. W celu określenia efektów entropowych w całym zakresie orientacji molekularnej wywołanej naprężeniami rozciągającymi zastosowano dwa przybliżenia statystyki molekularnej. Badania doświadczalne kinetyki krystalizacji orientowanej przeprowadzono dla orientowanej włókniny z polilaktydu (PLLA) oraz nieorientowanego granulatu PLLA jako przykładowego polimeru, z wykorzystaniem różnicowego kalorymetru skaningowego DSC. Przedstawiono znaczny wpływ orientacji molekularnej na szybkość nukleacji, wzrostu kryształów i szybkość krystalizacji, wynikający ze spadku entropii fazy amorficznej w warunkach orientacji. Ujęte jest to w rozszerzonych modelach Hoffmana i Lauritzena oraz Avramiego i Evansa dla orientowanej krystalizacji i w eksperymentalnych wynikach badań kalorymetrycznych DSC.

50.Meissner M., Prediction of Low-Frequency Sound Field in Rooms with Complex-Valued Boundary Conditions on Walls, VIBRATIONS IN PHYSICAL SYSTEMS, ISSN: 0860-6897, Vol.30, No.1, pp.1-8, 2019
Meissner M., Prediction of Low-Frequency Sound Field in Rooms with Complex-Valued Boundary Conditions on Walls, VIBRATIONS IN PHYSICAL SYSTEMS, ISSN: 0860-6897, Vol.30, No.1, pp.1-8, 2019

Abstract:
A modal representation of a room impulse response has been used to formulate expressions for low-frequency sound field in rooms of arbitrary shape. Based on theoretical results, a simulation program has been developed to predict a sound pressure distribution and a room transfer function for rectangular enclosure having walls covered by a material of complex impedance. Calculation results have shown that changes in the wall reactance entail a substantial modification of a sound pressure distribution. Furthermore, an influence of wall reactance on the room transfer function was investigated and it was discovered that a change in a reactance sign causes a shift in frequencies of modal vibrations excited in the room.

Keywords:
room acoustics, modal vibrations, room impulse response, complex wall impedance

51.Postek E., Pęcherski R.B., Nowak Z., Peridynamic simulation of crushing processes in copper open-cell foam, ARCHIVES OF METALLURGY AND MATERIALS, ISSN: 1733-3490, Vol.64, No.4, pp.1603 -1610, 2019
Postek E., Pęcherski R.B., Nowak Z., Peridynamic simulation of crushing processes in copper open-cell foam, ARCHIVES OF METALLURGY AND MATERIALS, ISSN: 1733-3490, Vol.64, No.4, pp.1603 -1610, 2019

Abstract:
In the last 20 years, a new meshless computational method has been developed that is called peridynamics. The method is based on the parallelized code. The subject of the study is the deformation of open-cell copper foams under dynamic compression. The computational model of virtual cellular material is considered. The skeleton structure of such a virtual cellular material can be rescaled according to requirements. The material of the skeleton is assumed as the oxygen free high conductivity (OFHC) copper. The OFHC copper powder can be applied in additive manufacturing to produce the open-cell multifunctional structures, e.g., crush resistant heat exchangers, heat capacitors, etc. In considered peridynamic computations the foam skeleton is described with the use of an elastic-plastic model with isotropic hardening. The dynamic process of compression and crushing with different impact velocities is simulated.

Keywords:
virtual cellular material, metallic foams, OFHC copper, elastic-plastic model, numerical methods, peridynamics, crushing process

52.Kiełczyński P., Ptasznik S., Szalewski M., Balcerzak A., Wieja K., Rostocki A.J., Application of Ultrasonic Methods for Evaluation of High-Pressure Physicochemical Parameters of Liquids, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.24425/aoa.2019.128496, Vol.44, No.2, pp.329-337, 2019
Kiełczyński P., Ptasznik S., Szalewski M., Balcerzak A., Wieja K., Rostocki A.J., Application of Ultrasonic Methods for Evaluation of High-Pressure Physicochemical Parameters of Liquids, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.24425/aoa.2019.128496, Vol.44, No.2, pp.329-337, 2019

Abstract:
An emerging ultrasonic technology aims to control high-pressure industrial processes that use liquids at pressures up to 800 MPa. To control these processes it is necessary to know precisely physicochemical properties of the processed liquid (e.g., Camelina sativa oil) in the high-pressure range. In recent years, Camelina sativa oil gained a significant interest in food and biofuel industries. Unfortunately, only a very few data characterizing the high-pressure behavior of Camelina sativa oil is available. The aim of this paper is to investigate high pressure physicochemical properties of liquids on the example of Camelina sativa oil, using efficient ultrasonic techniques, i.e., speed of sound measurements supported by parallel measurements of density. It is worth noting that conventional low-pressure methods of measuring physicochemical properties of liquids fail at high pressures. The time of flight (TOF) between the two selected ultrasonic impulses was evaluated with a cross-correlation method. TOF measurements enabled for determination of the speed of sound with very high precision (of the order of picoseconds). Ultrasonic velocity and density measurements were performed for pressures 0.1–660 MPa, and temperatures 3–30 C. Isotherms of acoustic impedance Za, surface tension Sigma and thermal conductivity k were subsequently evaluated. These physicochemical parameters of Camelina sativa oil are mainly influenced by changes in the pressure p, i.e., they increase about two times when the pressure increases from atmospheric pressure (0.1 MPa) to 660 MPa at 30 C. The results obtained in this study are novel and can be applied in food,and chemical industries.

Keywords:
Ultrasonic methods, speed of sound, acoustic impedance, surface tension, thermal conductivity, physicochemical properties

53.Nowicki A., Gambin B., Secomski W., Trawiński Z., Szubielski M., Tymkiewicz R., Olszewski R., Assessment of High Frequency Imaging and Doppler System for the Measurements of the Radial Artery Flow-Mediated Dilation, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.24425/aoa.2019.129276, Vol.44, No.4, pp.637-644, 2019
Nowicki A., Gambin B., Secomski W., Trawiński Z., Szubielski M., Tymkiewicz R., Olszewski R., Assessment of High Frequency Imaging and Doppler System for the Measurements of the Radial Artery Flow-Mediated Dilation, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.24425/aoa.2019.129276, Vol.44, No.4, pp.637-644, 2019

Abstract:
In the article we describe the new, high frequency, 20 MHz scanning/Doppler probe designed to measure the flow mediated dilation (FMD) and shear rate (SR) close to the radial artery wall. We compare two US scanning systems, standard vascular modality working below 12 MHz and high frequency 20 MHz system designed for FMD and SR measurements. Axial resolutions of both systems were compared by imaging of two closely spaced food plastic foils immersed in water and by measuring systolic/diastolic diameter changes in the radial artery. The sensitivities of Doppler modalities were also determined. The diagnostic potential of a high frequency system in measurements of FMD and SR was studied in vivo, in two groups of subjects, 12 healthy volunteers and 14 patients with stable coronary artery disease (CAD). Over three times better axial resolution was demonstrated for a high frequency system. Also, the sensitivity of the external single transducer 20 MHz pulse Doppler proved to be over 20 dB better (in terms of a signal-to-noise ratio) than the pulse Doppler incorporated into the linear array. Statistically significant differences in FMD and FMD/SR values for healthy volunteers and CAD patients were confirmed, p-values < 0:05. The areas under Receiver Operating Characteristic (ROC) curves for FMD and FMD/SR for the prediction CAD had the values of 0.99 and 0.97, respectively. These results justify the usefulness of the designed high-frequency scanning system to determine the FMD and SR in the radial artery as predictors of coronary arterial disease.

Keywords:
low mediated dilation; shear rate; axial resolution; elevation resolution; pulsed Doppler; ultrasonic imaging

54.Wójcik J., Secomski W., Żołek N., The Forces Driving Streaming in the Presence of Scatterers Mimicking the Blood Cells and the Contrast Agents, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.24425/aoa.2019.129722, Vol.44, No.4, pp.659-668, 2019
Wójcik J., Secomski W., Żołek N., The Forces Driving Streaming in the Presence of Scatterers Mimicking the Blood Cells and the Contrast Agents, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.24425/aoa.2019.129722, Vol.44, No.4, pp.659-668, 2019

Abstract:
Acoustical Driving Forces (ADF), induced by propagating waves in a homogeneous and inhomogeneous lossy fluid (suspension), are determined and compared depending on the concentration of suspended particles. Using integral equations of the scattering theory, the single particle (inclusion) ADF was calculated as the integral of the flux of the momentum density tensor components over the heterogeneity surface. The possibility of negative ADF was indicated. Originally derived, the total ADF acting on inclusions only, stochastically distributed in ambient fluid, was determined as a function of its concentration. The formula for the relative increase in ADF, resulting from increased concentration was derived. Numerical ADF calculations are presented. In experiments the streaming velocities in a blood-mimicking starch suspension (2 u m radius) in water and Bracco BR14 contrast agent (SF6 gas capsules, 1 um radius) were measured as the function of different inclusions concentration. The source of the streaming and ADF was a plane 2 mm diameter 20 MHz ultrasonic transducer. Velocity was estimated from the averaged Doppler spectrum obtained from originally developed pulsed Doppler flowmeter. Numerical calculations of the theoretically derived formula showed very good agreement with the experimental results.

Keywords:
streaming suspension; scattering; acoustical driving force; Doppler measurements; contrast agents

55.Domaradzki J., Lewandowski M., Żołek N., Lewandowski M., Optimization of Short-Lag Spatial Coherence Imaging Method, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.24425/aoa.2019.129275, Vol.44, No.4, pp.669-679, 2019
Domaradzki J., Lewandowski M., Żołek N., Lewandowski M., Optimization of Short-Lag Spatial Coherence Imaging Method, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.24425/aoa.2019.129275, Vol.44, No.4, pp.669-679, 2019

Abstract:
The computing performance optimization of the Short-Lag Spatial Coherence (SLSC) method applied to ultrasound data processing is presented. The method is based on the theory that signals from adjacent receivers are correlated, drawing on a simplified conclusion of the van Cittert-Zernike theorem. It has been proven that it can be successfully used in ultrasound data reconstruction with despeckling. Former works have shown that the SLSC method in its original form has two main drawbacks: time-consuming processing and low contrast in the area near the transceivers. In this study, we introduce a method that allows to overcome both of these drawbacks. The presented approach removes the dependency on distance (the “lag” parameter value) between signals used to calculate correlations. The approach has been tested by comparing results obtained with the original SLSC algorithm on data acquired from tissue phantoms. The modified method proposed here leads to constant complexity, thus execution time is independent of the lag parameter value, instead of the linear complexity. The presented approach increases computation speed over 10 times in comparison to the base SLSC algorithm for a typical lag parameter value. The approach also improves the output image quality in shallow areas and does not decrease quality in deeper areas

Keywords:
short lag spatial coherence; synthetic aperture; algorithm optimization; parallel processing

56.Sardelli L., Pacheco D.P., Zorzetto L., Rinoldi C., Święszkowski W., Petrini P., Engineering biological gradients, Journal of Applied Biomaterials & Functional Materials, ISSN: 2280-8000, DOI: 10.1177/2280800019829023, Vol.17, No.1, pp.2280800019829023-1-15, 2019
Sardelli L., Pacheco D.P., Zorzetto L., Rinoldi C., Święszkowski W., Petrini P., Engineering biological gradients, Journal of Applied Biomaterials & Functional Materials, ISSN: 2280-8000, DOI: 10.1177/2280800019829023, Vol.17, No.1, pp.2280800019829023-1-15, 2019

Abstract:
Biological gradients profoundly influence many cellular activities, such as adhesion, migration, and differentiation, which are the key to biological processes, such as inflammation, remodeling, and tissue regeneration. Thus, engineered structures containing bioinspired gradients can not only support a better understanding of these phenomena, but also guide and improve the current limits of regenerative medicine. In this review, we outline the challenges behind the engineering of devices containing chemical-physical and biomolecular gradients, classifying them according to gradient-making methods and the finalities of the systems. Different manufacturing processes can generate gradients in either in-vitro systems or scaffolds, which are suitable tools for the study of cellular behavior and for regenerative medicine; within these, rapid prototyping techniques may have a huge impact on the controlled production of gradients. The parallel need to develop characterization techniques is addressed, underlining advantages and weaknesses in the analysis of both chemical and physical gradients.

Keywords:
Graded scaffolds, rapid prototyping, bioinspired, microfluidic, gradient characterization, cartilage, bone

57.Kukla D., Zagórski A., Sarniak Ł., Ilościowa ocena sygnału prądów wirowych od wad w austenitycznych rurkach wymienników ciepła, BIULETYN INSTYTUTU SPAWALNICTWA, ISSN: 0867-583X, Vol.4, pp.66-72, 2019
58.Frydrych K., Crystal plasticity finite element simulations of the indentation test, COMPUTER METHODS IN MATERIALS SCIENCE / INFORMATYKA W TECHNOLOGII MATERIAŁÓW, ISSN: 1641-8581, Vol.19, No.2, pp.41-49, 2019
Frydrych K., Crystal plasticity finite element simulations of the indentation test, COMPUTER METHODS IN MATERIALS SCIENCE / INFORMATYKA W TECHNOLOGII MATERIAŁÓW, ISSN: 1641-8581, Vol.19, No.2, pp.41-49, 2019

Abstract:
The goal of the paper is to report the successful simulations of the nanoindentation problem. The finite-strain isotropic elasto-plasticity and crystal elasto-plasticity models used for the simulations are described. The developed contact formu-lation describing the contact with rigid surface approximating pyramidal indenter is presented. Both tensile stress-strain and indentation load-penetration curves obtained with a single set of material parameters are presented to be in the satisfactory agreement with experimental data. It seems that such a result is presented for the first time.

Keywords:
crystal plasticity, indentation, Al 6061-T6, nanoindentation, Vickers, Berkovich, CPFEM

59.Dąbrowski M., Dziedzic K., Antolik A., Glinicki M.A., Influence of the air voids distribution in concrete on the rate of water absorption, BMC-12, Brittle Matrix Composites, 2019-09-23/09-24, Warszawa (PL), pp.147-158, 2019
Dąbrowski M., Dziedzic K., Antolik A., Glinicki M.A., Influence of the air voids distribution in concrete on the rate of water absorption, BMC-12, Brittle Matrix Composites, 2019-09-23/09-24, Warszawa (PL), pp.147-158, 2019

Abstract:
Prolonged durability of concrete structures is closely related to the minimization of the transport of liquids in cement matrix. Capillary suction is a dominant mechanism of liquid transport, especially in moderate climate, where cyclic wetting-drying and freeze-thawing cycles occur. Air-entraining of concrete is the efficient way to prevent deterioration impact from environment. However, the influence of air voids distribution on the capillary suction is not well known. The purpose of the research was to assess the water absorption properties of the air entrained concrete. The concrete mixes with the air content from 1% to 16% and similar proportion of micropores to large air voids (A300/A) were prepared. The water absorption tests were performed using ASTM C1585 procedure. The following parameters were determined: Si – initial rate of water absorption, Ss – secondary rate of water absorption, tn – time of nick point, In - water absorption for tn, I60 – initial 60 seconds of water absorption. The results were compared with the air content in concrete. Additionally the compressive strength, porosity accessible to water and concrete resistivity were measured. The linear relationships between initial and secondary rate of water absorption and the air content in concrete were found. A significant changes of rate of water absorption in concrete when the air content change more than 6% were observed.

Keywords:
water absorption, air-entrained concrete, nick point, concrete resistivity, porosity accessible to water

60.Antolik A., Jóźwiak-Niedźwiedzka D., Dziedzic K., Bogusz K., Denis P., Potential of alkali silica reaction as a function of reactive form of quartz in fine aggregate, BMC-12, Brittle Matrix Composites, 2019-09-23/09-24, Warszawa (PL), pp.223-230, 2019
Antolik A., Jóźwiak-Niedźwiedzka D., Dziedzic K., Bogusz K., Denis P., Potential of alkali silica reaction as a function of reactive form of quartz in fine aggregate, BMC-12, Brittle Matrix Composites, 2019-09-23/09-24, Warszawa (PL), pp.223-230, 2019

Abstract:
In the present study the potential of alkali-silica reaction (ASR) in fine fraction of aggregate was analyzed. The investigation was focused on mineral composition of siliceous sand and its influence on ASR. Three siliceous sands from different origin and localization in Poland were tested. Petrographic analysis on thin sections was conducted. The automatic image analysis was used to estimate the content of reactive minerals (micro- and crypto-crystalline quartz). The XRD measurements were performed. Alkali-silica reactivity of fine aggregate was tested by mortar-bar test according to ASTM C1260 Standard. Petrographic analysis showed that all tested siliceous sands contained reactive form of quartz, micro- and cryptocrystalline. Mortar-bar tests according to ASTM C1260 indicated that one from the selected sands exceeded expansion over the limit and was considered as reactive. The content of reactive minerals in sands estimated by automatic image analysis corresponded to ASTM C1260 results. The higher content of reactive form of quartz in siliceous sand, the larger expansion of mortar-bar test.

Keywords:
Siliceous sand, Alkali-Silica Reaction (ASR), digital image analysis, micro- and cryptocrystalline quartz, expansion

61.Kowalewski Z.L., Szczęsny G., Libura T., Brodecki A., Destabilization of the comminuted clavicle shaft fracture due to breakage of the titanium locking plate - mechanical analysis, DAS 2019, 36th DANUBIA-ADRIA Symposium on Advances in Experimental Mechanics, 2019-09-24/09-27, Pilzno (CZ), pp.1-2, 2019
62.Libura T., Brodecki A., Kowalewski Z.L., Behaviour of glass woven reinforced thermoplastic laminates under uniaxial cyclic loading, PCM-CMM, 4th Polish Congress of Mechanics, 23rd International Conference on Computer Methods in Mechanics, 2019-09-08/09-12, Kraków (PL), pp.1-1, 2019
Libura T., Brodecki A., Kowalewski Z.L., Behaviour of glass woven reinforced thermoplastic laminates under uniaxial cyclic loading, PCM-CMM, 4th Polish Congress of Mechanics, 23rd International Conference on Computer Methods in Mechanics, 2019-09-08/09-12, Kraków (PL), pp.1-1, 2019

Keywords:
cyclic loading, damage evolution, laminate composites

63.Szymczak T., Brodecki A., Kowalewski Z.L., Mini-próbki w badaniach mechanicznych materiałów, XIII NKRM 2019, XIII Konferencja Nowe Kierunki Rozwoju Mechaniki, 2019-03-20/03-23, Będlewo (PL), pp.1-2, 2019
Szymczak T., Brodecki A., Kowalewski Z.L., Mini-próbki w badaniach mechanicznych materiałów, XIII NKRM 2019, XIII Konferencja Nowe Kierunki Rozwoju Mechaniki, 2019-03-20/03-23, Będlewo (PL), pp.1-2, 2019

Keywords:
mini-próbka, parametry mechaniczne, rozciąganie, skręcanie, pękanie

64.Ostrowski M., Błachowski B., Jankowski Ł., Pisarski D., Półaktywne sterowanie drganiami konstrukcji przy użyciu dynamicznie aktywowanych połączeń, SAM2019, XVIII Szkoła Analizy Modalnej, 2019-06-06/06-07, Kraków (PL), pp.1, 2019
Ostrowski M., Błachowski B., Jankowski Ł., Pisarski D., Półaktywne sterowanie drganiami konstrukcji przy użyciu dynamicznie aktywowanych połączeń, SAM2019, XVIII Szkoła Analizy Modalnej, 2019-06-06/06-07, Kraków (PL), pp.1, 2019

Abstract:
W ostatnim czasie wiele prac naukowych poświęcono problemom półaktywnego sterowania drganiami układów mechanicznych. Większość tych prac jednak dotyczy zagadnienia tłumienia drgań, natomiast znacznie mniej z nich obejmuje strategie sterowania na potrzeby odzyskiwania energii z drgających układów.

Celem niniejszej pracy jest opracowanie strategii półaktywnego sterowania drganiami, mającej za zadanie przenosić energię drgań wzbudzanych losowo do jednej wybranej postaci drgań własnych. Sterowanie takie realizowane jest przy pomocy dynamicznie rozłączanych węzłów konstrukcyjnych. Węzły w zależności od sygnału sterowania mogą być blokowane w celu przenoszenia momentu zginającego pomiędzy łączonym członami konstrukcji lub odblokowywane, aby pracować jak połączenie przegubowe.

Prowadzone badania podstawowe mają wiele potencjalnych zastosowań. Wraz ze zmianą postaci drgań, istnieje możliwość zmiany amplitudy w miejscach, w których zainstalowany jest tłumik lub urządzenie odzyskujące energię (ang. energy-harvester). Możliwe jest również szybkie przeniesienie energii mechanicznej do postaci drgań, która nie zakłóca funkcjonalności konstrukcji lub nie powoduje jej uszkodzenia bądź zmęczenia.

W porównaniu do sterowania aktywnego stosowanie sterowania półaktywnego pozwala obniżyć koszty układu, dodatkowo nie powodując destabilizacji konstrukcji [1]. Sterowanie takie może z powodzeniem znaleźć zastosowanie w konstrukcjach o wielu stopniach swobody [2]. Strategia półaktywnego sterowania z użyciem blokowalnych węzłów pierwotnie została opracowana w celu przeniesienia energii drgań do wyższych postaci własnych w celu skutecznej ich redukcji przez tłumienie materiałowe [3].

W niniejszej pracy zaprezentowany zostanie model matematyczny transferu energii oraz oparte na nim prawo sterowania. Dodatkowo przedstawiony zostanie przykład numeryczny pokazujący, że transfer energii mechanicznej jest możliwy nawet wtedy, gdy mierzone są tylko pierwsze – podstawowe – postacie drgań własnych.

Prowadzone badania zostały wsparte przez Narodowe Centrum Nauki w ramach projektu Re-Conf (DEC-2017/25/B/ST8/01800).

Keywords:
sterowanie półaktywne, analiza modalna, blokowane węzły,

65.Glinicki M.A., Jóźwiak-Niedźwiedzka D., Problem Reaktywności Kruszywa, TECH-BUD'2019, IV Konferencja Naukowo-Techniczna Nowoczesne Materiały, Techniki i Technologie we Współczesnym Budownictwie, 2019-11-13/11-15, Kraków (PL), pp.97-107, 2019
66.Poma Bernaola A., Boosting plastic degradation by a novel enzymatic paradigm, European Summit of Industrial Biotechnology (esib), 2019-11-18/11-20, Graz (AT), pp.48, 2019
Poma Bernaola A., Boosting plastic degradation by a novel enzymatic paradigm, European Summit of Industrial Biotechnology (esib), 2019-11-18/11-20, Graz (AT), pp.48, 2019

Abstract:
Our undeniable dependency on plastics is justified by the their technological versatility in different sectors of our societies. However, since their birth in our planet, it was noticed their lack of degradability under ambient conditions. Todays production worldwide has overcome 350 millions tonnes and this amount has created a global crisis known as the plastic pollution. We plan to show the steps towards the design of the new enzymatic paradigm for plastic degradation. Our project envision to stop the progress of the plastic pollution crisis and to make it fully part of the circular economy. Our approach will employ a rational design of novel enzymatic complex not reported before in nature in analogy as the plant cell wall degrading enzymes. The key feature of such nanomachine is the process of binding of several plastic degrading enzymes to a protein-scaffolding. It will be composed of multiple proteins that serve to integrate the enzymes and a substrate binding module. In contrast to the current paradigm free enzyme which is dominated by a non concerted degradation process, we expect our novel system to exploit the effect of having the enzymes very close to the plastic substrate and their synergy. Moreover, the modular character of our approach and the vast information in the field of hydrolases (endoglucanases) will boost the search of novel enzymes.

Keywords:
Plasticsome, bioengineering, molecular simulation, linker, esterase, Petase, CBM, enzyme, activity, polymer, PET

67.Zieliński T.G., Červenka M., On a relative shift in the periodic micro-geometry and other causes for discrepancy in the microstructure-based modelling of 3D-printed porous media, INTER-NOISE 2019, INTER-NOISE 2019 - 48th International Congress and Exhibition on Noise Control Engineering, 2019-06-16/06-19, Madrid (ES), No.1695, pp.1-10, 2019
Zieliński T.G., Červenka M., On a relative shift in the periodic micro-geometry and other causes for discrepancy in the microstructure-based modelling of 3D-printed porous media, INTER-NOISE 2019, INTER-NOISE 2019 - 48th International Congress and Exhibition on Noise Control Engineering, 2019-06-16/06-19, Madrid (ES), No.1695, pp.1-10, 2019

Abstract:
Samples with periodic microstructures, designed for good sound absorption, have been manufactured by 3D printing. Typically, however, the acoustical properties of the resulting samples differ from those predicted. Two causes of the discrepancies are (1) inaccuracies related to the 3D-printing resolution and (2) imperfections resulting from micro-fibres, micro-pores, and pore surface roughness, created during manufacture. Discrepancies due to the first cause can be addressed, post hoc, by updating the idealised periodic geometric model used for creating the codes for fabrication on the basis of a survey using a scanning microscope, or through computerised micro-tomography scans. Reducing the discrepancies due to the second cause requires a relatively significant further modelling effort. Another cause for small discrepancies is when two layers of the same periodic porous material and thickness differ only by a relative shift of the internal geometry of the periodic Representative Volume Element (RVE). This causes the absorption peaks to be shifted in frequency. A modelling procedure is proposed to take this into account.

Keywords:
Sound absorption, Periodic porous media, Additive manufacturing

68.Ostrowski M., Świercz A., Błachowski B., Tauzowski P., Jankowski Ł., Optimization of Sensor Placement Using Continuous Approaches, WEO2019, Workshop on Engineering Optimization 2019, 2019-11-04/11-04, Warszawa (PL), pp.22-23, 2019
Ostrowski M., Świercz A., Błachowski B., Tauzowski P., Jankowski Ł., Optimization of Sensor Placement Using Continuous Approaches, WEO2019, Workshop on Engineering Optimization 2019, 2019-11-04/11-04, Warszawa (PL), pp.22-23, 2019

Abstract:
The present study provides a comprehensive framework for sensor layout optimization aiming at accurate estimation of the modal coordinates coming from the structural response. The proposed procedure consists of two steps briefly described below. The first step is a selection of vibrational modes taking part in the motion of structures during their normal operation – in this case subjected to traveling load. Among these structures there are various types of bridges especially railway bridges. In the case of present study structural responses are obtained from rigorous finite element (FE) model of the bridge. The FE model is calibrated with measured response of real bridge located in Huta Zawadzka. The calibration process is based on the displacement signals of the bridge under the traveling load. In the second step modes of interest are selected and a set of candidate sensor locations is proposed. It is a subset of all degrees of freedom (DOFs) of the FE model from which several locations are chosen as best possible locations for the displacement sensors. The above sensor placement problem is a combinatorial task. Many methods for solving
such problems have been developed previously, but in the case of large scale structures they require tremendous computational effort. To reduce this effort the so-called convex relaxation is incorporated into optimization process. The technique consists in reformulation of combinatorial problem into continuous convex one. Then, the convex relaxation is achieved by introducing the so-called sensor density function, which assigns a certain metric for individual candidate sensor location. Next, the value of this function is optimized in such a way that it maximize determinant of the Fisher Information Matrix. It has been shown that above algorithm is very effective and is distributing a number of sensors in several iterations only. Finally, it is worth noting that presented method can be used to distribute sensors for structural health monitoring. Moreover, it can be also applied in modal control strategies in vibration suppression.

69.Logo J., Tauzowski P., Blachowski B., Topology optimization of elastoplastic structures under reliability constraints: A first order approach, CIVIL-COMP-OPTI 2019, Fifth International Conference on Soft Computing & Optimisation in Civil, Structural and Environmental Engineering, 2019-09-16/09-19, Riva del Garda (IT), pp.1-3, 2019
Logo J., Tauzowski P., Blachowski B., Topology optimization of elastoplastic structures under reliability constraints: A first order approach, CIVIL-COMP-OPTI 2019, Fifth International Conference on Soft Computing & Optimisation in Civil, Structural and Environmental Engineering, 2019-09-16/09-19, Riva del Garda (IT), pp.1-3, 2019

Abstract:
Structural safety is a critical aspect in modern engineering practice. One of the factors leading to the risk of failure is the variability of design parameters. To be able to estimate the risk of failure, this variability should be taken into account in design process. One way to tackle this issue is to assume a random nature of selected design parameters. These parameters can represent: loads acting on a structure, material properties or shape parameters. Minimizing the structural mass in the process of topology optimization is equivalent to removing the material from the initial, usually regular design space. This process can lead also to a reduction of the structural safety. Therefore, apart from deterministic constraints (such as stresses, displacements or load capacity), it is also worth to control the probabilistic ones. The purpose of this work is to introduce in topology optimization of elastoplastic structures an additional constraint on the probability of failure. Deterministic constraints, in the form of constraints on stresses, are imposed on elastoplastic analysis and utilized by the return mapping algorithm.
One of the difficulties coming from the application of these random effects in the process topology optimization is its numerical complexity. Topological optimization itself is a complex issue. Adding a structural safety estimation can extend this process significantly. Fortunately, in the field of reliability analysis, which deals with determining reliability, there are methods that allow for relatively fast estimation of the probability of failure. These are First and Second Order Reliability Methods (FORM, SORM). Only several finite element iterations are sufficient to determine the probability of failure. These methods are based on the concept of the design point or the most probable point. This is the point on the limit state surface that lies closest to the mean point, and represents the most probable failure scenario. Moreover, approximation of limit state surface is linear (FORM) or quadratic (SORM). This allows to estimate quite accurately low probabilities of failure. Such a low probability of failure should characterized a safe structure. The search for a design point is based on the iterative formula developed by Rackwitz and Fiesler.
The paper will present the formulation of the elasto-plastic problem of structural analysis as well as the detailed description of the algorithm for topology optimization under reliability constraint. The paper will be illustrated by examples, in which we will demonstrate, how probability of failure changes in the topological optimization process.

Keywords:
topology optimization, elasto-plastic structures, reliability analysis, probabilistic design

70.Zieliński T.G., Opiela K.C., Pawłowski P., Dauchez N., Boutin T., Kennedy J., Trimble D., Rice H., Differences in sound absorption of samples with periodic porosity produced using various Additive Manufacturing Technologies, ICA 2019, 23rd International Congress on Acoustics integrating 4th EAA Euroregio 2019, 2019-09-09/09-13, Aachen (DE), DOI: 10.18154/RWTH-CONV-239456, pp.4505-4512, 2019
Zieliński T.G., Opiela K.C., Pawłowski P., Dauchez N., Boutin T., Kennedy J., Trimble D., Rice H., Differences in sound absorption of samples with periodic porosity produced using various Additive Manufacturing Technologies, ICA 2019, 23rd International Congress on Acoustics integrating 4th EAA Euroregio 2019, 2019-09-09/09-13, Aachen (DE), DOI: 10.18154/RWTH-CONV-239456, pp.4505-4512, 2019

Abstract:
With a rapid development of modern Additive Manufacturing Technologies it seems inevitable that they will sooner or later serve for production of specific porous and meta-porous acoustic treatments. Moreover, these new technologies are already being used to manufacture original micro-geometric designs of sound absorbing media in order to test microstructure-based effects, models and hypothesis. In the view of these statements, this work reports differences in acoustic absorption measured for porous specimens which were produced from the same CAD-geometry model using several additive manufacturing technologies and 3D-printers. A specific periodic unit cell of open porosity was designed for the purpose. The samples were measured acoustically in the impedance tube and also subjected to a thorough microscopic survey in order to check their quality and look for the discrepancy reasons.

Keywords:
Sound absorption, Additive Manufacturing Technologies

71.Opiela K.C., Zieliński T.G., Adaptation of the equivalent-fluid model to the additively manufactured acoustic porous materials, ICA 2019, 23rd International Congress on Acoustics integrating 4th EAA Euroregio 2019, 2019-09-09/09-13, Aachen (DE), DOI: 10.18154/RWTH-CONV-239799, pp.1216-1223, 2019
Opiela K.C., Zieliński T.G., Adaptation of the equivalent-fluid model to the additively manufactured acoustic porous materials, ICA 2019, 23rd International Congress on Acoustics integrating 4th EAA Euroregio 2019, 2019-09-09/09-13, Aachen (DE), DOI: 10.18154/RWTH-CONV-239799, pp.1216-1223, 2019

Abstract:
Recent investigations show that the normal incidence sound absorption in 3D-printed rigid porous materials is eminently underestimated by numerical calculations using standard models. In this paper a universal amendment to the existing mathematical description of thermal dispersion and fluid flow inside rigid foams is proposed which takes account of the impact of the additive manufacturing technology on the acoustic properties of produced samples. The porous material with a motionless skeleton is conceptually substituted by an equivalent fluid with effective properties evaluated from the Johnson-Champoux-Allard-Pride-Lafarge model. The required macroscopic transport parameters are computed from the microstructural solutions using the hybrid approach. A cross-functional examination of the quality (shape consistency, representative surface roughness, etc.) of two periodic specimens obtained from additive manufacturing processes is additionally performed in order to link it to the results of the multiscale acoustic modelling. Based on this study, some of the transport parameters are changed depending on certain quantities reflecting the actual quality of a fabricated material. The developed correction has a considerable influence on the predicted value of the sound absorption coefficient such that the original discrepancies between experimental and numerical curves are significantly diminished.

Keywords:
Rigid porous material, Additive manufacturing, Sound absorption

72.Wasilewski M., Pisarski D., On suboptimal switched state-feedback control of semi-active vibrating structures, ACC, 2019 American Control Conference, 2019-07-10/07-12, Philadelphia (US), pp.3135-3141, 2019
Wasilewski M., Pisarski D., On suboptimal switched state-feedback control of semi-active vibrating structures, ACC, 2019 American Control Conference, 2019-07-10/07-12, Philadelphia (US), pp.3135-3141, 2019

Abstract:
An efficient suboptimal semi-active control for mitigating structural vibration is studied. The control relies on a practical state-feedback switching law and, as demonstrated in the previous research, it guarantees the asymptotic stability. The focus of this work is to provide the qualitative and quantitative analysis on the control’s optimality in the sense of an energy-related performance index. Firstly, a method for optimal selection of the passive strategy that underlies a design of the control’s switching law is proposed. Next,
the conditions asserting the performance of the semi-active control are formulated and proven. Finally, the controller’s performance is validated by numerical experiments involving a 2DOF semi-active structure, where the suboptimal control is compared to the optimal open-loop solution and a heuristic strategy.

73.Nosewicz S., Rojek J., Wawrzyk K., Kowalczyk P., Maciejewski G., Maździarz M., Multiscale prediction of powder properties during pressure-assisted sintering, CM4P, Computational Methods in Multi-scale, Multi-uncertainty and Multi-physics Problems, 2019-07-15/07-17, Porto (PT), pp.1, 2019
74.Nosewicz S., Rojek J., Wawrzyk K., Kowalczyk P., Maciejewski G., Maździarz M., Modeling of sintering process of intermetallic NiAl powder using multiscale approach, IWCMM29, 29th International Workshop on Computational Mechanics of Materials, 2019-09-15/09-18, Dubrovnik (HR), pp.1, 2019
75.Nosewicz S., Rojek J., Wawrzyk K., Kowalczyk P., Maciejewski G., Maździarz M., Three-scale modelling of hot pressing process, PCM-CMM, 4th Polish Congress of Mechanics, 23rd International Conference on Computer Methods in Mechanics, 2019-09-08/09-12, Kraków (PL), pp.1, 2019
76.Golasiński K.M., Pieczyska E.A., Polish-Japanese Joint Research on a Multifunctional Titanium Alloy Gum Metal, 11. Kongres Societas Humboldtiana Polonorum pod patronatem Prezydenta RP Andrzeja Dudy i Prezydenta RFN Franka-Waltera Steinmeiera, 2019-09-12/09-15, Szczecin (PL), pp.90-91, 2019
77.Madan N., Rojek J., Nosewicz S., The deformable discrete element method - formulation and application, YIC2019, 5th ECCOMAS Young Investigators Conference, 2019-09-01/09-06, Kraków (PL), pp.1-2, 2019
78.Hołobut P., Statistical properties of the representative volume element of random materials, PCM-CMM, 4th Polish Congress of Mechanics, 23rd International Conference on Computer Methods in Mechanics, 2019-09-08/09-12, Kraków (PL), pp.1-1, 2019
Hołobut P., Statistical properties of the representative volume element of random materials, PCM-CMM, 4th Polish Congress of Mechanics, 23rd International Conference on Computer Methods in Mechanics, 2019-09-08/09-12, Kraków (PL), pp.1-1, 2019

Keywords:
Representative Volume Element, Effective Properties, Random Microstructure

79.Hołobut P., Assessment of the Size of the Representative Volume Element of Random Heterogeneous Materials, CM4P, Computational Methods in Multi-scale, Multi-uncertainty and Multi-physics Problems, 2019-07-15/07-17, Porto (PT), pp.1-2, 2019
80.Kukla D., Kowalewski Z.L., Assessment of failure development in 7075 aluminum alloy on the basis of damage parameters change during the high-cycling fatigue, PCM-CMM, 4th Polish Congress of Mechanics, 23rd International Conference on Computer Methods in Mechanics, 2019-09-08/09-12, Kraków (PL), pp.1-1, 2019
Kukla D., Kowalewski Z.L., Assessment of failure development in 7075 aluminum alloy on the basis of damage parameters change during the high-cycling fatigue, PCM-CMM, 4th Polish Congress of Mechanics, 23rd International Conference on Computer Methods in Mechanics, 2019-09-08/09-12, Kraków (PL), pp.1-1, 2019

Keywords:
Fatigue, Damage Evolution, Aluminum Alloy

81.Ustrzycka A., Mróz Z., Kucharski S., Kowalewski Z.L., Analysis of fatigue crack initiation caused by cyclic microplasticity, PCM-CMM, 4th Polish Congress of Mechanics, 23rd International Conference on Computer Methods in Mechanics, 2019-09-08/09-12, Kraków (PL), pp.1-1, 2019
Ustrzycka A., Mróz Z., Kucharski S., Kowalewski Z.L., Analysis of fatigue crack initiation caused by cyclic microplasticity, PCM-CMM, 4th Polish Congress of Mechanics, 23rd International Conference on Computer Methods in Mechanics, 2019-09-08/09-12, Kraków (PL), pp.1-1, 2019

Keywords:
Fatigue Crack Initiation, Damage Evolution, Optical Methods, Indentation Method

82.Kowalewski Z.L., Kukla D., Ustrzycka A., Evaluation of fatigue damage development supported by nondestructive technique, 10-th GGP, The 10th German-Greek-Polish Symposium, 2019-09-15/09-18, Będlewo (PL), pp.1-2, 2019
Kowalewski Z.L., Kukla D., Ustrzycka A., Evaluation of fatigue damage development supported by nondestructive technique, 10-th GGP, The 10th German-Greek-Polish Symposium, 2019-09-15/09-18, Będlewo (PL), pp.1-2, 2019

Abstract:
This paper presents an attempt to use the Electronic Speckle Pattern Interferometry (ESPI) and Digital Image Correlation (DIC) for damage evaluation and its monitoring on specimens made of the P91 steel and aluminide coated nickel super-alloys subjected to monotonic or cyclic loading.

83.Libura T., Kowalewski Z.L., Szymczak T., Wpływ cyklicznego obciążenia na odporność na uderzenia laminatu z żywicy termoplastycznej wzmocnionej tkaniną z włókna szklanego, XIII NKRM 2019, XIII Konferencja Nowe Kierunki Rozwoju Mechaniki, 2019-03-20/03-23, Będlewo (PL), pp.41-42, 2019
Libura T., Kowalewski Z.L., Szymczak T., Wpływ cyklicznego obciążenia na odporność na uderzenia laminatu z żywicy termoplastycznej wzmocnionej tkaniną z włókna szklanego, XIII NKRM 2019, XIII Konferencja Nowe Kierunki Rozwoju Mechaniki, 2019-03-20/03-23, Będlewo (PL), pp.41-42, 2019

Keywords:
kompozyty, żywice termoplastyczne, badania zmęczeniowe, udarność

84.Makowska K., Kowalewski Z.L., Wykorzystanie parametrów szumu Barkhausena do oceny właściwości mechanicznych materiałów konstrukcyjnych, XIII NKRM 2019, XIII Konferencja Nowe Kierunki Rozwoju Mechaniki, 2019-03-20/03-23, Będlewo (PL), pp.47-48, 2019
Makowska K., Kowalewski Z.L., Wykorzystanie parametrów szumu Barkhausena do oceny właściwości mechanicznych materiałów konstrukcyjnych, XIII NKRM 2019, XIII Konferencja Nowe Kierunki Rozwoju Mechaniki, 2019-03-20/03-23, Będlewo (PL), pp.47-48, 2019

Keywords:
stale wysokowytrzymałe, szum Barkhausena, twardość, wytrzymałość na rozciąganie, mikrostruktura

85.Kowalewski Z.L., Nowak Z., Pęcherski R., Libura T., Identification of effects associated to dynamic testing using shpb or dict- experiment and numerical analysis, DynaMAT, The 13th WORKSHOP on DYNAMIC BEHAVIOR OF MATERIALS AND ITS APPLICATIONS IN INDUSTRIAL PROCESSES, 2019-04-17/04-19, Nicosia (CY), pp.1-2, 2019
86.Kowalewski Z.L., Ustrzycka A., Szymczak T., Makowska K., Damage identification supported by nondestructive testing techniques, ICPDF, INTERNATIONAL SYMPOSIUM ON PLASTICITY, 2019-01-03/01-09, Panama (PA), pp.1-1, 2019
87.Kowalewski Z.L., Szymczak T., Analysis of material effects during perforation – experiments and attempts in numerical modelling, 16th German-Polish Workshop, Dynamiczne Problemy w Mechanicznych Systemach, 2019-09-01/09-05, Seebergen (DE), pp.1-1, 2019
88.Faraj R., Jankowski Ł., Graczykowski C., Holnicki-Szulc J., Ball-screw inerter for optimal impact mitigation, RANM2019, Fourth International Conference on Recent Advances in Nonlinear Mechanics, 2019-05-07/05-10, Łódź (PL), pp.1-2, 2019
Faraj R., Jankowski Ł., Graczykowski C., Holnicki-Szulc J., Ball-screw inerter for optimal impact mitigation, RANM2019, Fourth International Conference on Recent Advances in Nonlinear Mechanics, 2019-05-07/05-10, Łódź (PL), pp.1-2, 2019

Abstract:
The inerter is a subject of intensive research in the field of structural dynamics and control since 2002, when it was introduced by Malcolm Smith. Inerter-based devices are implemented in various practical applications, which include protective systems in earthquake engineering, suspensions of trains, road vehicles and aircraft landing gears. The majority of inerter applications proposed in the literature concerns vibration mitigation problems, e.g., implementation of the inerter in tuned mass dampers. In contrast, this contribution discusses an application of the inerter for solving the problem of impact absorption. The inerter was previously considered as a shock-absorber in [Ref.] but optimal impact mitigation was not provided. Recently, the authors have studied a simple inerter device based on the ball-screw mechanism with a variable thread lead, which ensures minimization of the generated reaction force and the optimal impact absorption. This contribution sums up the results obtained in the full-length journal paper, currently under review .

Keywords:
ball-screw inerter, impact absorption, passive absorber, variable inertance, variable moment of inertia, inertial damping

89.Graczykowski C., Faraj R., Model Identification Adaptive Control of fluid-based shock-absorbers for impact mitigation, RANM2019, Fourth International Conference on Recent Advances in Nonlinear Mechanics, 2019-05-07/05-10, Łódź (PL), pp.1-2, 2019
Graczykowski C., Faraj R., Model Identification Adaptive Control of fluid-based shock-absorbers for impact mitigation, RANM2019, Fourth International Conference on Recent Advances in Nonlinear Mechanics, 2019-05-07/05-10, Łódź (PL), pp.1-2, 2019

Abstract:
Novel semi-active shock-absorbers dedicated to impact absorption utilize high-performance valves
to control actual flow of the fluid between absorber chambers, modify generated reaction force and
obtain optimal process of energy dissipation. Although various control strategies providing
optimal impact mitigation were elaborated, they were based on strict assumptions such as apriori
knowledge of impact loading and lack of system disturbances. In contrast, more challenging
objective is to develop control systems maintaining efficient and robust operation in the case of
incomplete information about system excitation and disturbances in the process. The possible
solution is application of self-adaptive systems based on sequential measurements of system state,
such as elaborated by authors Hybrid Prediction Control involving bang-bang and continuous valve
actions. In this contribution improvement of self-adaptive system is achieved by introduction of
the online identification of system parameters and its application to compute optimal control.

Keywords:
impact mitigation, fluid-based shock-absorber, Model Identification Adaptive Control, semi-active control

90.Dyniewicz B., Bajer C.I., The Gao beam under a moving inertial load and harmonic compression, MATEC Web of Conferences, 2019-05-21/05-24, Rzeszów (PL), pp.1-8, 2019
Dyniewicz B., Bajer C.I., The Gao beam under a moving inertial load and harmonic compression, MATEC Web of Conferences, 2019-05-21/05-24, Rzeszów (PL), pp.1-8, 2019

Abstract:
In the present work the dynamics of the system of a mass moving on the beam is investigated in detail numerically in the case of vibrations about a buckled state. The differential equation that describes the motion is strongly nonlinear. Simulations are based on the space-time finite element method. It enabled us easily determine the influence of the moving inertial particle. At the computational stage it becomes a real problem when the mass particle traverses joints of neighbouring elements. The results of representative and interesting computer simulations are enclosed.

91.Secomski W., Klimonda Z., Olszewski R., Nowicki A., Quantitative analysis of the 5 μl thrombus dissolution process using 40 kHz – 6 MHz ultrasound, IUS 2019, IEEE, International Ultrasonics Symposium , 2019-10-06/10-09, Glasgow (GB), pp.1-4, 2019
Secomski W., Klimonda Z., Olszewski R., Nowicki A., Quantitative analysis of the 5 μl thrombus dissolution process using 40 kHz – 6 MHz ultrasound, IUS 2019, IEEE, International Ultrasonics Symposium , 2019-10-06/10-09, Glasgow (GB), pp.1-4, 2019

Abstract:
Precise quantitative analysis of the sonothrombolysis process is required to minimise the amount of thrombolytic drug dangerous for the patient, because it can cause internal hemorrhage. Verification of the effects of other drugs or other procedures for the elimination of thrombi, for example ultrasound contrast microbubbles, also requires quantitative research. For microscopic examination of the thrombolysis process, the Rexolite parallel plate flow chamber has been used. The internal dimensions of the chamber were 11x1x20 mm. In order to eliminate the standing wave, the incident wave was perpendicular to the reflected one. The narrowband chirp driven transducer suppressed the surface waves in Rexolite. The clot dissolution was processed at 40 kHz – 6 MHz ultrasound frequencies and 2 W/cm2 spatial averaged, temporal averaged intensities. The thrombus was obtained from a 5 μl drop of blood placed directly inside a flow chamber. The flow chamber was filled with the cell culture medium Dulbecco's modified Eagle's medium. The flow in the chamber was forced by a peristaltic pump at a speed of 3.8 ml/min. The Actilyse tissue plasminogen activator at a concentration of 10 μg/ml was added. The similarity of the thrombolysis process obtained from 5 μl of blood with a similar volume fragment cut from a larger thrombus was experimentally verified. Thrombus volume was estimated from microscopic photographs by calculating its surface area and its optical transparency. At 2 W/cm2 ultrasound intensity, took the thrombus 4, 8, 9 and 12 minutes to completely dissolve for the centre ultrasound frequencies of 40.9, 149, 209 kHz and 1.02 MHz, respectively. For higher frequencies, the thrombus only reduced its volume by 82%, 69% and 27% for the frequencies 2.10, 3.34 and 6.63 MHz, respectively. Sonication for 20 - 60 minutes did not cause further dissolution of thrombi.

Keywords:
ultrasound, blood, thrombus, thrombolysis, parallel plate flow chamber

92.Kowalewski Z.L., Libura T., Experimental characterization of magnesium alloy thin sheets using anti-buckling fixture, LMM 2019, International Conference on Lightweight Materials and Manufacture, 2019-10-09/10-12, Changsha (CN), pp.1-1, 2019
93.Kruglenko E., Krajewski M., Tymkiewicz R., Litniewski J., Gambin B., Porównanie hipertermii magnetycznej i ultradźwiękowej w próbkach agarowych z dodatkiem nanocząstek magnetycznych, XXIX Sympozjum PTZE, Zastosowania elektromagnetyzmu we współczesnej inżynierii i medycynie, 2019-06-09/06-12, Janów Podlaski, Polska (PL), No.1, pp.183-184, 2019
94.Korczak I., Kruglenko E., Secomski W., Gambin B., Efficiency of cooling system designed for transplant surgery by numerical model and Doppler measurements, IFA2019, International Symposium on Fluid Acoustics IFA2019 Sopot, Poland, May 20–22, 2019, 2019-05-20/05-22, Sopot (PL), DOI: 10.24425/aoa.2019.128504, No.44, pp.408, 2019
95.Popławski B., Mikułowski G., Mróz A., Wiszowaty R., Jankowski Ł., Controllable transmission of moments for semi-active damping of structural vibrations, RANM2019, Fourth International Conference on Recent Advances in Nonlinear Mechanics, 2019-05-07/05-10, Łódź (PL), pp.1-2, 2019
Popławski B., Mikułowski G., Mróz A., Wiszowaty R., Jankowski Ł., Controllable transmission of moments for semi-active damping of structural vibrations, RANM2019, Fourth International Conference on Recent Advances in Nonlinear Mechanics, 2019-05-07/05-10, Łódź (PL), pp.1-2, 2019

Abstract:
In the recent decades, a significant stream of research in structural control has focused on semi-active control approaches. The two constitutive characteristics of a semi-active system are its low consumption of energy and the capability of smart self-adaptation. The inspiration can be traced back to Nature, where dynamic and energy-efficient self-adaptation to varying external conditions is a ubiquitous mode of operation. These ideas are fundamentally different from the paradigms behind the active control (active counteraction) and the passive approaches (passive absorption). In applications to mitigation of vibrations in structural control, within the spectrum of the semi-active techniques, there are two basic approaches that can be identified as: 1) stimulation of local dissipation in actuators, which basically amounts to maximization of the local force--displacement loops, and 2) local triggering of the global material dissipation mechanisms, which is called the prestress accumulation--release (PAR) control strategy. This contribution reports on a specific control technique from the second group.

96.Rustighi E., Kaal W., Herold S., Jankowski Ł., Prediction of acoustic emission of a rigid electrodes DEAP loudspeaker, ICA 2019, 23rd International Congress on Acoustics integrating 4th EAA Euroregio 2019, 2019-09-09/09-13, Aachen (DE), pp.7345-7352, 2019
Rustighi E., Kaal W., Herold S., Jankowski Ł., Prediction of acoustic emission of a rigid electrodes DEAP loudspeaker, ICA 2019, 23rd International Congress on Acoustics integrating 4th EAA Euroregio 2019, 2019-09-09/09-13, Aachen (DE), pp.7345-7352, 2019

Abstract:
Dielectric Electro-Active Polymers (DEAP) are lighweight materials whose dimensions change significantly when subjected to electric stimulation. One form of DEAP construction consists of a thin layer of dielectric sandwiched between two perforated rigid electrodes. They can be used as an actuator or a sensor and have the potential to be an effective replacement for many conventional transducers. This paper refers to their use as loudspeakers. To date, flat DEAP loudspeakers have been portotyped and tested but no numeric prediction of their acoustic performance has been presented. In this paper an elemental model is presented. The electro-dynamic behaviour of the electrodes and dielectric layers is taken into account. The acoustic impedance is calculated assuming baffled conditions. The impedances of the individual layers are stacked together and preliminary results are shown.

Keywords:
loudspeaker, DEAP, sound power

97.Pręgowska A., Proniewska K., van Dam P., Dudek D., Szczepański J., €žAutomatic arrhythmia detection form two-channel ambulatory ECG recordings using Shannon Information Theory-based algorithms, NFIC, 20th New Frontiers in Interventional Cardiology, 2019-12-11/12-13, Kraków (PL), pp.9, 2019
98.Proniewska K., Dołęga-Dolegowski D., Pręgowska A., Dudek D., Augmented reality as a doctor support to meet the General Data Protection Regulation in Europe, NFIC, 20th New Frontiers in Interventional Cardiology, 2019-12-11/12-13, Kraków (PL), pp.10, 2019
99.Libura T., Kowalewski Z.L., Matadi Boumbimba R., Rusinek A., Gerard P., Behaviour of glass woven reinforced thermoplastic laminates under uniaxial cyclic loading, DynaMAT, The 13th WORKSHOP on DYNAMIC BEHAVIOR OF MATERIALS AND ITS APPLICATIONS IN INDUSTRIAL PROCESSES, 2019-04-17/04-19, Nicosia (CY), pp.1-2, 2019
100.Kukla D., Kolek Ł., Gradzik A., Evaluation and classification of grinding burns by eddy current method, DMIUT 2019, DIAGNOSTYKA MATERIAŁÓW I URZĄDZEŃ TECHNICZNYCH, 2019-05-29/05-31, Gdańsk (PL), pp.1-1, 2019
101.Graczykowski C., Knap L., Holnicki-Szulc J., Wołejsza Z., Development of Control Strategies for Vertical Mobility of Adaptive Telescopic High-altitude Aerostats, SMART 2019, 9th ECCOMAS Thematic Conference on Smart Structures and Materials, 2019-07-08/07-11, Paris (FR), pp.1-8, 2019
Graczykowski C., Knap L., Holnicki-Szulc J., Wołejsza Z., Development of Control Strategies for Vertical Mobility of Adaptive Telescopic High-altitude Aerostats, SMART 2019, 9th ECCOMAS Thematic Conference on Smart Structures and Materials, 2019-07-08/07-11, Paris (FR), pp.1-8, 2019

Abstract:
In this article we propose a new concept of adaptive telescopic high-altitude
aerostat designed in a modular form which allows for sequential changes of volume during
the flight. The proposed telescopic aerostat can be easily enlarged or contracted due to
application of multi-segmented construction, controllable segments’ couplings and precise
adjustment of internal pressure obtained using additional gas tank, valve and compressor.
Conducted changes of aerostat volume allow to precisely control generated lift force and to
obtain desired paths of ascending and descending. The paper briefly presents development of
control strategies aimed at: i) reaching the subsequent altitudes in the shortest period of time,
ii) reaching these altitudes at the smallest cost defined as total work done by the compressor.
The obtained results show high potential of the proposed innovative concept of the aerostat.

Keywords:
helium airship, control of vertical mobility, reduced energy consumption, optimal ascending and descending paths

102.Graczykowski C., Lewiński T., Applications of Michell’s Theory in Design of High-rise Buildings, Large-scale Roofs and Long-span Bridges, WEO2019, Workshop on Engineering Optimization 2019, 2019-11-04/11-04, Warszawa (PL), pp.12-13, 2019
103.Graczykowski C., Lewiński T., On the Applications of Michell’s Theory in Design of Buildings, Bridges and other Engineering Structures, Form and Force, FORM and FORCE 2019, joint international conference of the IASS 60th Anniversary Symposium (IASS SYMPOSIUM 2019) and the 9th Int. Conference on Textile Composites and Inflatable Structures (STRUCTURAL MEMBRANES 2019), 2019-10-07/10-10, Barcelona (ES), pp.1-1, 2019
104.Jarząbek D.M., Harvey C., Levintant-Zayonts N., Daraio C., Dziekoński C., Wojciechowski T., Gniadek M., Pathak S., Mechanical properties of N+ion irradiated vertically aligned carbon nanotube arrays studied by nanoindentation, EUROMAT 2019, European Congress and Exhibition on Advanced Materials and Processes 2019, 2019-09-01/09-05, Stockholm (SE), No.PM6-5, pp.464, 2019
105.Jenczyk P., Jarząbek D., Influence of protective Ni coating on SiC particles on tribological properties of coelectrodeposited Ni-SiC composite coating, EUROMAT 2019, European Congress and Exhibition on Advanced Materials and Processes 2019, 2019-09-01/09-05, Stockholm (SE), pp.763, 2019
106.Stańczak M., Fras T., Blanc L., Pawłowski P., Rusinek A., Numerical Modeling of Honeycomb Structure Subjected to Blast Loading, LS-DYNA2019, 12th European LS-DYNA Conference 2019, 2019-05-14/05-16, Koblenz (DE), pp.1-10, 2019
Stańczak M., Fras T., Blanc L., Pawłowski P., Rusinek A., Numerical Modeling of Honeycomb Structure Subjected to Blast Loading, LS-DYNA2019, 12th European LS-DYNA Conference 2019, 2019-05-14/05-16, Koblenz (DE), pp.1-10, 2019

Abstract:
The main objective of this study is related to the modeling of an aluminum thin-walled honeycomb structure under blast loading. The blast test is performed by means of an explosively driven shock tube (EDST). A planar shock wave is generated by a small amount of an explosive charge detonated in front of the tube. The honeycomb core is compressed by a movement of the steel plate located at the end of the tube. In the experiment, the honeycomb deformation is recorded by a high-speed camera and the absorbed loading by the structure is measured by a force sensor fixed on the rear sample face. The simulation of the material behavior is carried out using the Lagrangian approach implemented in LS-DYNA, ver. R9.0.1. The shock pressure generated by the explosion is recalculated to define the force applied to the plate being in contact (*AUTOMATIC_SURFACE_TO_SURFACE with friction) with the honeycomb and causing its deformation. The honeycomb is meshed by shell elements with a default formulation ELFORM: BELYTSCHKO-TSAY. The front plate is assumed as a rigid body to induce a uniform deformation of the honeycomb structure modeled using *MAT_SIMPLIFIED_JOHNSON_COOK 098 with parameters published in, [1-2]. The simulations are performed for different number of unit cells to define the honeycomb, from a single cell to fifty-three cells, aiming to indicate a minimal cell number required to model properly the entire structure. A dependence of numerical results on the mesh size, unit cell dimensions, friction conditions and the strain rate has been verified. The comparison between values of the load absorbed by the sample crushed numerically and experimentally shows a good agreement providing an insight into mechanisms of blast wave absorption by honeycomb structures. Such an analysis may be further applicable in development of advanced cellular structures applied to dissipate blast energy.

107.Nakielski P., Pawłowska S., Urbanek-Świderska O., Woźniak-Jezierska K., Barczewska M., Maksymowicz W., Injectable scaffolds for tissue engineering, ISSCR 2019, International Society for Stem Cell Research Annual Meeting, 2019-06-26/06-29, Los Angeles (US), pp.277-277, 2019
Nakielski P., Pawłowska S., Urbanek-Świderska O., Woźniak-Jezierska K., Barczewska M., Maksymowicz W., Injectable scaffolds for tissue engineering, ISSCR 2019, International Society for Stem Cell Research Annual Meeting, 2019-06-26/06-29, Los Angeles (US), pp.277-277, 2019

Abstract:
Intervertebral disc diseases are a significant medical problem affecting many people around the world. In Poland, the statistics of the Social Insurance Institution (Medical Abuse in 2016) indicate that low back pains and other intervertebral disc diseases constitute 17% of the total number of days of sick leave. In connection with the above, current work describes design of a composite scaffold as a carrier in cell therapy, which will contribute to the regeneration of the intervertebral disc, including the increase of its height. Our composite scaffold include nanofibers that were prepared with the use of the electrospinning method. This method is a simple but powerful technique for fabricating desirable nano- and microfibers by using a high potential electric field. Human Mesenchymal stem cells (MSCs) were cultured on the scaffold from poly(L-lactide). Proliferation kits and fluorescence microscopy were used to asses cells’ viability and adherence to the nanofibers’ surface. hMSCs were efficiently cultured on the nanofibrous scaffold. Cells could be readily detected in porous structure of the scaffold after 7 and 14 days of culture. Viability and proliferation kits proved that the material is not toxic. Drug release from nanofibrous material of model growth factor was conducted with pharmacopeia protocols. Drug release of the 14 kDa growth factor was achieved for 14 days without burst release. Nanofibrous biomaterials prove their advances in many tissue engineering applications. Adjustable porosity of the scaffold and the biocompability of biomaterial make it perfect candidate for cells’ scaffold in many medical procedures and also as a drug release carrier. With the use of single nanofibers, such biomaterials can also be readily used in minimally invasive procedures to regenerate IVD.

Keywords:
nanofibers, IVD, MSC

108.Nakielski P., De Sio L., Buda R., Guglielmelli A., Pawlowska S., Urbanek O., Kowalewski T.A., Pierini F., Photo-responsive PNIPAM-Gold Nanorods Hydrogel For Biomedical Applications, NOMA2019, The 14th Mediterranean Workshop and Topical Meeting, 2019-06-02/06-08, Cetraro (IT), pp.80-80, 2019
Nakielski P., De Sio L., Buda R., Guglielmelli A., Pawlowska S., Urbanek O., Kowalewski T.A., Pierini F., Photo-responsive PNIPAM-Gold Nanorods Hydrogel For Biomedical Applications, NOMA2019, The 14th Mediterranean Workshop and Topical Meeting, 2019-06-02/06-08, Cetraro (IT), pp.80-80, 2019

Abstract:
Stimuli-responsive drug delivery systems are gaining a lot of interest due to their numerous advantages, especially when compared to conventional pharmaceutical dosage forms. One of the examples is photo stimulation that together with nanometer size agents, having high absorption in the near-infrared region, generate heat due to the interaction with light. Stimuli-responsive hydrogels with gold nanorods (AuNRs), that are used as photothermal converters, can aid in releasing drugs on-demand with a fast release rate through different mechanisms. Here we report an easy method for preparing AuNRs encapsulated in a poly(N-isopropylacrylamide) (PNIPAm) hydrogel that release water-soluble drugs due to photo stimulation. PNIPAm-AuNRs demonstrated remote, pulsatile drug release and ex vivo action after irradiation using a NIR laser. Morphological and chemical characterization as well as drug release studies were carried out to confirm the material’s ability to supply different doses of drugs on demand and to study the release mechanism. By combining the photothermal property of AuNRs and thermal-responsive effect of PNIPAm, the hydrogel shows fast thermal/photoresponse, high heating rate, high structural integrity and increased drug release due to phase change mechanism.

Keywords:
drug delivery systems, nanofibers

109.Pieczyska E., Golasiński K., Maj M., Furuta T., Kuramoto S., Development of Strain Localization in a Beta-Titanium Alloy Gum Metal Analyzed by Infrared Camera and Digital Image Correlation for Various Strain Rates, Proceedings — Open Access Journal, ISSN: 2504-3900, DOI: 10.3390/proceedings2019027051, Vol.27, No.1, pp.51-1-4, 2019
Pieczyska E., Golasiński K., Maj M., Furuta T., Kuramoto S., Development of Strain Localization in a Beta-Titanium Alloy Gum Metal Analyzed by Infrared Camera and Digital Image Correlation for Various Strain Rates, Proceedings — Open Access Journal, ISSN: 2504-3900, DOI: 10.3390/proceedings2019027051, Vol.27, No.1, pp.51-1-4, 2019

Abstract:
Effects of thermomechanical couplings were studied in a new beta Ti alloy by IR and DIC techniques. The obtained stress-strain curves confirmed low Young’s modulus and high strength of the alloy. The determined values of yield strength increases and values of elongation till rupture decreases with increasing strain rate. It was found, by using fast and sensitive infrared camera, that the large limit of the Gum Metal reversible nonlinear deformation originates from mechanisms of dissipative nature, probably exothermic stress-induced transition of ” nanodomains.

Keywords:
Titanium alloy, Gum Metal, strain rate, infrared camera, temperature change, DIC

110.Pierini F., Lanzi M., Nakielski P., Pawłowska S., Urbanek O., Kowalewski T.A., Light-matter interaction in electrospun nanofibers: novel conjugated polymer-based one-dimensional nanostructures for organic solar cell applications, NOMA2019, The 14th Mediterranean Workshop and Topical Meeting, 2019-06-02/06-08, Cetraro (IT), pp.55-55, 2019
Pierini F., Lanzi M., Nakielski P., Pawłowska S., Urbanek O., Kowalewski T.A., Light-matter interaction in electrospun nanofibers: novel conjugated polymer-based one-dimensional nanostructures for organic solar cell applications, NOMA2019, The 14th Mediterranean Workshop and Topical Meeting, 2019-06-02/06-08, Cetraro (IT), pp.55-55, 2019

Abstract:
Single-material organic solar cells (SMOCs) based on fullerene-grafted polythiophenes are considered promising devices for organic solar cells (OSCs). The main efforts in this field focus on the chemical tailoring of polymer molecules to reduce the side effects of charge recombination. These advances have made it possible to obtain a power conversion efficiency (PCE) close to conventional bulk heterojunction (BHJ) cells. So far, however, SMOCs still show inadequate efficiencies due to ineffective charge transport.
Here we show how SMOC efficiency can be strongly increased by optimizing the supramolecular and nanoscale structure of the active layer, while achieving the highest reported efficiency value (PCE = 5.58%) [1]. The enhanced performance may be attributed to well-packed and properly oriented polymer chains. The hierarchical structure is given by the incorporation of electrospun one-dimensional nanostructures obtained from polymer chain stretching. Our results suggest that the active material optimization obtained by the use of electrospun nanofibers plays a key role in the development of efficient SMOCs.

111.Nakielski P., Urbanek O., Pawłowska S., Kowalewski T.A., Pierini F., Externally triggered on-demand drug release from stimuli-responsive hydrogel-based electrospun nanofibers and their composites, Electrospin 2019, 6th International Conference on Electrospinning 2019 , 2019-06-19/06-21, Shanghai (CN), pp.63-63, 2019
Nakielski P., Urbanek O., Pawłowska S., Kowalewski T.A., Pierini F., Externally triggered on-demand drug release from stimuli-responsive hydrogel-based electrospun nanofibers and their composites, Electrospin 2019, 6th International Conference on Electrospinning 2019 , 2019-06-19/06-21, Shanghai (CN), pp.63-63, 2019

Abstract:
Pulsatile drug delivery systems are gaining a lot of interest because of their numerous advantages, especially when compared to conventional pharmaceutical dosage forms [1]. These materials are time- and site-specific drug delivery systems which can minimize deleterious side effects of conventional drug administration systems. Nevertheless, the delivery systems that are of particular interest are the ones with reversible on-off switching capability, because they allow the delivery of therapeutic agents at the proper time after a predetermined lag time. Among the polymers used for biomedical applications, hydrogels are a class of materials of particular significance, because they can provide spatial and temporal control over the release of various types of drugs. Stimuli-responsive hydrogels can release drugs on-demand with a fast release rate through different mechanisms. The effectiveness of this process can be maximized using nanostructured materials with a large surface-area-to-volume ratio such as electrospun nanofibers. Current challenges in the development of hydrogel electrospun fibrous nanomaterials lie in the lack of spinnability of pure hydrogel precursor solutions. Addressing this issue, we firstly designed a new core-shell nanofibrous material in which the poly(N-isopropylacrylamide)-derivative hydrogel is confined within a shell of a spinnable polymer (Figure 1a). Alternatively, we developed a scaffold material in which electrospun nanofibers loaded with different bioactive molecules where surrounded by a stimuli-responsive hydrogel (Figure 1b). Morphological and chemical characterization as well as drug release studies were carried out to confirm the material’s ability to supply different doses of drugs on demand and to study the release mechanism.

112.Pawłowska S., Zembrzycki K., Kowalewski T.A., Pierini F., Micro and nano-object interaction analysis with femtonewton resolution by Atomic Force Microscopy and Optical Tweezers hybrid system, AFM Bio Med Conference, 2019-09-02/09-06, Munster (DE), pp.65-65, 2019
Pawłowska S., Zembrzycki K., Kowalewski T.A., Pierini F., Micro and nano-object interaction analysis with femtonewton resolution by Atomic Force Microscopy and Optical Tweezers hybrid system, AFM Bio Med Conference, 2019-09-02/09-06, Munster (DE), pp.65-65, 2019

Abstract:
Gaining knowledge of the solid-solid interactions and hydrodynamic and mechanical properties is crucial for understanding the processes and dynamics of molecular interactions, biological and nano- structures and also to find their future applications.
Atomic force microscopy (AFM) is a versatile technique for nanoscale imaging purposes and for quantify analysis of force at the nanonewton scale. Unfortunately, due to technical limitations and restrictions related to the mechanical properties of cantilevers, this technique cannot detect small forces on the femtonewton scale and analyse the stiffness of very soft materials such as biological tissues or hydrogels. AFM is also use to manipulate materials, however, AFM-based manipulation systems are slow and imprecise. To distinguish, Optical Tweezers (OT) are scientific instruments that can trap small particles and manipulate nano- and micro-materials with much higher precision. The AFM / OT hybrid system is a high-resolution imaging instrument with a lower force limit of detection. It is capable of non-invasively manipulating of nanomaterials, single molecules and living cells, measuring forces with femtonewton accuracy, detecting motion with nanometer (10-9 m) precision and to manipulate objects, but also to obtain images directly in the same sample. The combination of AFM with Optical Tweezers will provide significant advances in biophysical research and in the study of the mechanical properties of nanomaterials [1]. In our system we combine Optical Tweezers with commercial AFM to create an instrument capable of working in hybrid mode. It allows simultaneous manipulation of biological systems of greater complexity and the analysis of their properties. Performed by us, experiments showed that AFM/OT system is a unique technique for visualization of the analysed materials, trapping single micro-objects and measure the interactions (in the range of femtonewton) between single particles. The results obtained by AFM/OT confirm that this equipment is a very useful technique also for determination the mechanical properties of very soft materials (e.g. hydrogels) [2].

113.Melikhov Y., Ekiel-Jeżewska M.L., Jas G.S., Kuczera K., Hydrodynamic approach to compute reorientation times of NATA protein in different solutions: comparison with Molecular Dynamics and experiment, APS/DFD 2019, 72nd Annual Meeting of the APS Division of Fluid Dynamics, 2019-11-23/11-26, Seattle (US), pp.1, 2019
114.Nowak Z., Numerical simulation of crushing processes in metallic open-cell foam, PCM-CMM, 4th Polish Congress of Mechanics, 23rd International Conference on Computer Methods in Mechanics, 2019-09-08/09-12, Kraków (PL), pp.1, 2019
115.Nowak Z., Nowak M., Pęcherski R.B., On the energy absorbtion in open cell foams under dynamic loading, DynaMAT, The 13th WORKSHOP on DYNAMIC BEHAVIOR OF MATERIALS AND ITS APPLICATIONS IN INDUSTRIAL PROCESSES, 2019-04-17/04-19, Nicosia (CY), pp.1-2, 2019
116.Pęcherski R.B., Rusinek A., Frąś T., Nowak M., Nowak Z., Energetyczny warunek plastyczności materiałów ortotropowych wykazujących asymetrię zakresu sprężystego, OMIS 2019, XIII Konferencja Naukowa Odkształcalność Metali i Stopów, 2019-11-19/11-22, Łańcut (PL), pp.48-49, 2019
117.Miklewska A., Krajewski M., Kruglenko E., Tymkiewicz R., Gambin B., Wpływ stężenia nanocząstek superparamagnetycznych na wydajność hipertermii magnetycznej , XXIX Sympozjum PTZE, Zastosowania elektromagnetyzmu we współczesnej inżynierii i medycynie, 2019-06-09/06-12, Janów Podlaski, Polska (PL), No.1, pp.217-218, 2019
118.Dłużewski P., Domagała J., Kret S., Jarosz D., Teisseyre H., Critical thickness and misfit dislocations in rocksalt ZnMgO layers grown on MgO (100), ICMM6, 6th International Conference on Material Modelling, 2019-06-26/06-28, Lund (SE), pp.1-1, 2019
Dłużewski P., Domagała J., Kret S., Jarosz D., Teisseyre H., Critical thickness and misfit dislocations in rocksalt ZnMgO layers grown on MgO (100), ICMM6, 6th International Conference on Material Modelling, 2019-06-26/06-28, Lund (SE), pp.1-1, 2019

Abstract:
Zinc oxide has wurtzite structure (wz-ZnO) at ambient conditions. Due to the promising bandgap (4.0-7.8eV) we consider the misfit stress for the growth of rock salt rs-Zn$_x$Mg$_{1-x}$O layers on rock salt MgO. At the ambient conditions, a solid solution of ZnO in MgO is stable only up to 13%. Nevertheless, due to the misfit stress the range of chemical composition of thermodynamically stable layers can be extended.

We consider a mechanism of the dislocation network formation at the interface rs-Zn$_x$Mg$_{1-x}$O/MgO. Based on the dislocation theory, many different analytic formulas for critical layer thickness have been derived, cf. Hu (1991), Brown (2002). The formulas concern the critical thickness of the layers which retain thermodynamically stable at atmospheric pressure. On the other hand, for thin layers which lose the stability earlier, before the stress relaxation, we can expect a lower critical thickness. We present a derivation of an analytic formula for the critical thickness of rs-Zn$_x$Mg$_{1-x}$O layers which lose the stability due to the rocksalt-wurtzite phase transition, cf. Lu et al. (2016). In the new formula the dependency of the onset elastic energy $E(sigma, x)$ of the rs$
ightarrow$wz phase transition is taken into account. In the general case this energy depends on the misfit stress and chemical composition.

Hu, S.M. (1991) J. Appl. Phys. 69, 7901–7903.
Braun, A., at al. (2002) J. Cryst. Growth, 241, 231–234.
Lu, C.-Y.J. et al. (2016) J. Chem. Phys. 144, 214704.

119.Ekiel-Jeżewska M., Tradycje i nowoczesność, Gazeta Samorządowa MIM, ISSN: 1507-4447, Vol.4/276, pp.16-17, 2019
120.Klimonda Z., Karwat P., Piotrzkowska-Wróblewska H., Dobruch-Sobczak K., Litniewski J., Ultrasound scattering statistics predicts the result of neoadjuvant chemotherapy of breast tumors at an early stage of treatment, IUS 2019, IEEE, International Ultrasonics Symposium , 2019-10-06/10-09, Glasgow (GB), pp.1-3, 2019
121.Karwat P., Klimonda Z., Piotrzkowska-Wróblewska H., Dobruch-Sobczak K., Litniewski J., Quantitative ultrasound examination of peritumoral tissue improves classification of breast lesions, IUS 2019, IEEE, International Ultrasonics Symposium , 2019-10-06/10-09, Glasgow (GB), pp.1-3, 2019
122.Broniszewska P., Anodic Oxidation of AlSi10Mg Alloy Manufactured by DMLS, AMM, ADDITIVE MANUFACTURING MEETING 2019, 2019-09-18/09-19, Wrocław (PL), pp.38, 2019
Broniszewska P., Anodic Oxidation of AlSi10Mg Alloy Manufactured by DMLS, AMM, ADDITIVE MANUFACTURING MEETING 2019, 2019-09-18/09-19, Wrocław (PL), pp.38, 2019

Abstract:
Direct Metal Laser Sintering is a powder bed fusion process, which allows direct production of elements with complex shapes and very good mechanical properties. However, regardless of manufacturing technology elimination of some materials’ weaknesses is definitely tough to eliminate. These weaknesses might be excluded by surface engineering.This poster presents results of producing oxidized films on AlSi10Mg alloy manufactured by Direct Metal Laser Sintering using EOSM280 system equipped with 400W Yb fiber laser and standard EOS AlSi10Mg powder. AlSi10Mg is a near-eutectic die casting alloy which is applied to automotive and aviation industries. The density of printed samples was under 99%. We used 3 different methods of oxidation: traditional electrochemical oxidation, electrochemical oxidation in lower temperature (hard anodizing) and plasma electrochemical oxidation. Processes lasted 20 or 25 minutes. Traditional and hard anodizing was carried out in H2SO4 with the voltage in the range of 18.5-32.5 V. Plasma oxidation was carried out in 2 g/l KOH + 4 g/l Na2SiO3 and the applied voltage was between 190 and 225 V. Metallography, SEM and EDS proved that we received Al2O3 oxides on the AlSi10Mg surfaces. All produced films were thin (2-5 um), providing slightly increased microhardness and roughness of the surface. Roughness depends especially on electric current parameters applied in the oxidation process. Therefore the structure of layers manufactured by plasma electrochemical oxidation was more irregular and porous. All films had high adhesion which was confirmed by scratch tests.

Keywords:
DMLS, electrochemical oxidation, anodizing, aluminum alloy, AlSi10Mg

123.Kiełczyński P., Szalewski M., Balcerzak A., Wieja K., Ptasznik S., Rostocki A.J., High-Pressure Phase Transitions and Thermophysical Parameters of Camelina Sativa Oil Investigated by Ultrasonic Methods, FSciT-2019, World Summit on Advancement in Food Science and Technology, 2019-11-12/11-13, Valencia (ES), pp.6-6, 2019
Kiełczyński P., Szalewski M., Balcerzak A., Wieja K., Ptasznik S., Rostocki A.J., High-Pressure Phase Transitions and Thermophysical Parameters of Camelina Sativa Oil Investigated by Ultrasonic Methods, FSciT-2019, World Summit on Advancement in Food Science and Technology, 2019-11-12/11-13, Valencia (ES), pp.6-6, 2019

Abstract:
Knowledge of high-pressure behavior of the processed liquids is necessary to control technological processes in many branches of industry (e.g., in chemical, pharmaceutical and food industries). However, data on high-pressure behavior of liquids are still incomplete. The aim of this study is to investigate the high-pressure behavior (i.e., thermopysical parameters and possible high-pressure phase transitions) of liquids (on the example of Camelina sativa oil), applying ultrasonic methods (i.e., sound velocity and parallel density measurements). Camelina sativa (false flax) oil has found application in many branches of industry as well as a raw material for biofuel production. Generally, conventional methods for measuring thermophysical properties of liquids fail at high pressures. The solution to the problem can be the use of ultrasonic methods. Ultrasonic measurements were performed at f = 5 MHz for pressures 0.1 - 660 MPa, and for temperatures 3 - 30 ºC. Pronounced high-pressure phase transitions were discovered by the authors in Camelina sativa oil. The use of ultrasonic methods has enabled the determination of many physicochemical parameters of Camelina sativa oil, such as: 1) adiabatic compressibility β_a, 2) thermal expansion coefficient α_p, 3) specific heat at constant pressure c_p, 4) thermal conductivity k and 5) thermal diffusivity a. The results obtained in this study are novel and can be employed to design and control technological processes in many branches of industry

Keywords:
Ultrasonic methods, high pressure, thermophysical properties, Camelina sativa

124.Kiełczyński P., Szalewski M., Balcerzak A., Wieja K., Search for Optimum Parameters of Love Wave Sensors. Development of Exact Analytical Formulas for Sensor Sensitivities, IUS 2019, IEEE, International Ultrasonics Symposium , 2019-10-06/10-09, Glasgow (GB), pp.1-4, 2019
Kiełczyński P., Szalewski M., Balcerzak A., Wieja K., Search for Optimum Parameters of Love Wave Sensors. Development of Exact Analytical Formulas for Sensor Sensitivities, IUS 2019, IEEE, International Ultrasonics Symposium , 2019-10-06/10-09, Glasgow (GB), pp.1-4, 2019

Abstract:
In this work we analyze basic characteristics of Love wave sensors implemented in waveguide structures composed of a lossy viscoelastic surface layer deposited on a lossless elastic substrate. It has to be noted that Love wave sensors working at ultrasonic frequencies have the highest mass density sensitivity S_σ^(v_p ) among all known ultrasonic sensors, such as QCM, Lamb wave or Rayleigh wave sensors. In this paper we have established an exact analytical formula for the mass density sensitivity S_σ^(v_p ) of the Love wave sensors in the form of an explicit algebraic expression. Subsequently, using this developed analytical formula, we compared theoretically the mass density sensitivity S_σ^(v_p ) for various Love wave waveguide structures, such as: (1) lossy PMMA surface layer on lossless Quartz substrate and (2) lossy PMMA on lossless Diamond. The performed analysis shows that the mass density sensitivity S_σ^(v_p ) for a sensor with a structure PMMA on Diamond is four times higher than that of a PMMA on Quartz structure. It was found that the mass density sensitivity S_σ^(v_p ) for Love wave sensors increases with the increase of the ratio: bulk shear wave velocity in the substrate to bulk shear wave velocity in the surface layer.

Keywords:
Love waves, mass sensitivity, dispersion equation, viscoelastic layers

125.Kiełczyński P., Ptasznik S., Kalinowski A., Rostocki A.J., Wysokociśnieniowe parametry fizykochemiczne oleju z lnianki siewnej (camelina sativa) wyznaczone metodami ultradźwiękowymi, XXVII Międzynarodowa Konferencja Naukowa, Postępy w Technologii Tłuszczów Roślinnych , 2019-05-22/05-24, Kazimierz Dolny (PL), pp.29-30, 2019
Kiełczyński P., Ptasznik S., Kalinowski A., Rostocki A.J., Wysokociśnieniowe parametry fizykochemiczne oleju z lnianki siewnej (camelina sativa) wyznaczone metodami ultradźwiękowymi, XXVII Międzynarodowa Konferencja Naukowa, Postępy w Technologii Tłuszczów Roślinnych , 2019-05-22/05-24, Kazimierz Dolny (PL), pp.29-30, 2019

Abstract:
W tej pracy przedstawione zostały wyniki badań właściwości fizykochemicznych oleju z lnianki siewnej (Camelina sativa) w zakresie dużych ciśnień. Olej z lnianki siewnej znalazł zastosowanie w wielu dziedzinach przemysłu takich jak: spożywczy, farmaceutyczny, kosmetyczny. Olej z lnianki siewnej stosowany jest również jako surowiec do produkcji biopaliw. Te biopaliwa mogą być zastosowane do napędu samolotów odrzutowych (np. F-18 Hornet, Boeing 747, Airbus A-320). Zaletą tych biopaliw jest niska emisyjność czynników szkodliwych dla środowiska (np. dwutlenku węgla). Znajomość parametrów fizykochemicznych olejów jest niezbędna w projektowaniu wysokociśnieniowych procesów technologicznych przetwarzania i konserwacji żywności. Pomiar tych parametrów fizykochemicznych cieczy w zakresie dużych ciśnień metodami klasycznymi jest bardzo trudny prawie niemożliwy. Rozwiązaniem problemu może być zastosowanie metod ultradźwiękowych. Metody ultradźwiękowe dają się z powodzeniem zastosować do pomiaru tych parametrów fizykochemicznych w zakresie dużych ciśnień. Stosują metody ultradźwiękowe (tj. pomiar prędkości dźwięku wraz z równoległym pomiarem gęstości oleju) wyznaczono następujące parametry fizykochemiczne oleju z lnianki siewnej: 1) ściśliwość adiabatyczną β_a 2) ściśliwość izotermiczną β_T 3) współczynnik rozszerzalności cieplnej α_p 4) ciepło właściwe c_p 5) napięcie powierzchniowe σ 6) przewodność cieplną k 7) współczynnik wyrównywania temperatury (dyfuzyjność cieplną) a. Pomiary wykonano w zakresie ciśnień od ciśnienia atmosferycznego do 650 MPa oraz dla wartości temperatur od 3 °C do 30 °C. Uzyskane wyniki są oryginalne i nowatorskie i mogą być zastosowane w przemyśle spożywczym i chemicznym.

126.Wojnar R., Kinetic equation for the pair distribution function in the Boltzmann gas, 32nd Marian Smołuchowski Symposium on Statistical Physics, 2019-09-18/09-20, Kraków (PL), pp.35, 2019
127.Wołowicz J., Lissowski A., Wojnar R., How to Construct BC Helix From the Simplest Children's Toy: The Equilateral Triangle, World Congress on Physics, 2019-10-17/10-18, Berlin (DE), pp.14, 2019
128.Bielski W., Wojnar R., Brinkman's regulatization of Darcian seepage, PCM-CMM, 4th Polish Congress of Mechanics, 23rd International Conference on Computer Methods in Mechanics, 2019-09-08/09-12, Kraków (PL), pp.396-MS12-CR, 2019
129.Pelka M., Majek K., Będkowski J., Testing the affordable system for digitizing USAR scenes, SSRR 2019, IEEE INTERNATIONAL SYMPOSIUM ON SAFETY,SECURITY AND RESCUE ROBOTICS, 2019-09-02/09-04, Würzburg (DE), DOI: 10.1109/SSRR.2019.8848929, pp.104-105, 2019
Pelka M., Majek K., Będkowski J., Testing the affordable system for digitizing USAR scenes, SSRR 2019, IEEE INTERNATIONAL SYMPOSIUM ON SAFETY,SECURITY AND RESCUE ROBOTICS, 2019-09-02/09-04, Würzburg (DE), DOI: 10.1109/SSRR.2019.8848929, pp.104-105, 2019

Abstract:
Affordable technological solutions are always welcome, thus we decided to test the backpack based 3D mapping system for digitizing USAR scenes. The system is composed of Intel RealSense Tracking Camera T265, three Velodynes VLP16, custom electronics for multi-lidar synchronization and VR Zotac GO backpack computer equipped with GeForce GTX1070. This configuration allows the operator to collect and process 3D point clouds to obtain a consistent 3D map. To reach satisfactory accuracy we use RealSense as initial guess of trajectory from Visual Odometry (VO). Lidar odometry corrects trajectory and reduces scale error from VO. The academic 6DSLAM is used for loop closure and finally classical ICP algorithm refines the final 3D point cloud. All steps can be done in the field in reasonable time. The VR backpack can be used for virtual travel over digital content afterwords. Additionally deep neural network is used to perform online object detection using Relsense camera input.

130.Tasinkiewicz J., Lewandowski M., Walczak M., 3D/4D hybrid spectral domain synthetic aperture image reconstruction method for hand-held ultrasound systems, IUS 2019, IEEE, International Ultrasonics Symposium , 2019-10-06/10-09, Glasgow (GB), pp.1-4, 2019
Tasinkiewicz J., Lewandowski M., Walczak M., 3D/4D hybrid spectral domain synthetic aperture image reconstruction method for hand-held ultrasound systems, IUS 2019, IEEE, International Ultrasonics Symposium , 2019-10-06/10-09, Glasgow (GB), pp.1-4, 2019

Abstract:
In the last few decades 3D/4D ultrasonography has been gaining increasing popularity not only as a scientific research topic but also as a new modality of medical imaging in clinical applications. However, design and implementation of 3D/4D device for high quality ultrasound imaging within portable, handheld systems is a technological challenge. Design of transmit/receive (TX/RX) electronics for efficient operation with 2D array transducers, comprised of thousands of elements, enormous amount of input/output data that must be transferred and processed, power consumption limitation are just a few of the difficulties that arise. No less important is development of reliable and numerically efficient algorithms for 3D/4D imaging which should take all these restrictions into account. The main objective of this paper is to present a new hybrid spectral domain imaging (HSDI) method that delivers an original and innovative solution for the technical limitations of modern ultrasonography 3D/4D. The developed image reconstruction method is based on the plane-wave insonification (PWI) with sub-aperture data acquisition combined with frequency domain (FD) data processing. The performance of the method was tested using the Field II simulated acoustic data of 3D cyst phantom. For a 3D low-resolution image (LRI) comprised of 64×64×512 pixels the proposed HSDI method is about 100 times faster, in the case of a single 3D, than its counterpart based on the PWI synthetic aperture time domain (TD) method for a single TX/RX event. On the other hand, the frame rate increase is proportional to the number of sub-apertures used for a single high-resolution image (HRI) synthesis

131.Fura Ł., Dera W., Dziekoński C., Kujawska T., Experimental evaluation of the impact of ultrasound exposure parameters on necrotic lesions induced in tissue by a robotic ultrasound-guided hifu ablation device for treating solid tumors in small animals, ISTU 2019, The 19th International Symposium for Therapeutic Ultrasound, 2019-06-13/06-15, Barcelona (ES), pp.1, 2019
132.Nosewicz S., Rojek J., Chmielewski M., Pietrzak K., Discrete element simulations of hot pressing of intermetallic matrix composites, MBMST-2019, 13th International Conference: Modern Building Materials, Structures and Techniques, 2019-05-16/05-17, Vilnius (LT), pp.1, 2019
133.Fura Ł., Dera W., Dziekoński C., Kujawska T., Evaluation of targeting accuracy of a robotic ultrasound imaging-guided HIFU ablation device for treating solid tumors in small animals, 2019 ICU Bruges, 2019 International Congress on Ultrasonics, 2019-09-03/09-06, Bruges (BE), pp.1, 2019
134.Fura Ł., Dera W., Dziekoński C., Kujawska T., Experimental evaluation of the accuracy of targeting of a robotic ultrasound imaging-guided hifu ablation device for treating solid tumors in small animals, ISTU 2019, The 19th International Symposium for Therapeutic Ultrasound, 2019-06-13/06-15, Barcelona (ES), pp.1, 2019
135.Lumelskyj D., Rojek J., Lazarescu L., Banabic D., Experimental and numerical comparison of the Nakajima formability test with limit strain prediction using the time-dependent algorithm., MBMST-2019, 13th International Conference: Modern Building Materials, Structures and Techniques, 2019-05-16/05-17, Vilnius (LT), pp.1, 2019
Lumelskyj D., Rojek J., Lazarescu L., Banabic D., Experimental and numerical comparison of the Nakajima formability test with limit strain prediction using the time-dependent algorithm., MBMST-2019, 13th International Conference: Modern Building Materials, Structures and Techniques, 2019-05-16/05-17, Vilnius (LT), pp.1, 2019

Abstract:
This work presents an investigation on the determination of forming limit curves (FLCs) by finite element simulations and experimental approach. Nakajima formability test has been chosen for the experimental studies and numerical analysis. The onset of localized necking has been determined using the criteria studied in the authors’ earlier works, based on the analysis of the principal strains evolution in time. The criterion is based on the analysis of the through-thickness thinning (through-thickness strain) and its first time derivative in the most strained zone. The onset of necking is assumed to occur at the point corresponding to a sudden change of the slope of the strain rate vs. time curve. The limit strains have been determined for different specimens undergoing deformation at different strain paths covering the whole range of the strain paths typical for sheet forming processes. Therefore, determined limit strains allowed us to construct experimental and numerical FLC determined using the presented algorithm. The FLCs have been compared with the conventional FLC determined according to the ISO 12004 standard, showing quite a good agreement. These results indicate that the used methodology of the limit strain determination can be used in finite element simulations as a potential alternative tool to determine formability limits for the sheet forming processes.

Keywords:
Steel and aluminum structures

136.Jarosik P., Lewandowski M., Automatic Ultrasound Guidance Based on Deep Reinforcement Learning, IUS 2019, IEEE, International Ultrasonics Symposium , 2019-10-06/10-09, Glasgow (GB), pp.475-478, 2019
Jarosik P., Lewandowski M., Automatic Ultrasound Guidance Based on Deep Reinforcement Learning, IUS 2019, IEEE, International Ultrasonics Symposium , 2019-10-06/10-09, Glasgow (GB), pp.475-478, 2019

Abstract:
Ultrasound is becoming the modality of choice for everyday medical diagnosis, due to its mobility and decreasing price. As the availability of ultrasound diagnostic devices for untrained users grows, appropriate guidance becomes desirable. This kind of support could be provided by a software agent, who easily adapts to new conditions, and whose role is to instruct the user on how to obtain optimal settings of the imaging system during an examination. In this work, we verified the feasibility of implementing and training such an agent for ultrasound, taking the deep reinforcement learning approach. The tasks it was given were to find the optimal position of the transducer’s focal point (FP task) and to find an appropriate scanning plane (PP task). The ultrasound environment consisted of a linear-array transducer acquiring information from a tissue phantom with cysts forming an object-of-interest (OOI). The environment was simulated in the Field-II software. The agent could perform the following actions: move the position of the probe to the left/right, move focal depth upwards/downwards, rotate the probe clockwise/counter-clockwise, or do not move. Additional noise was applied to the current probe setting. The only observations the agent received were B-mode frames. The agent acted according to stochastic policy modeled by a deep convolutional neural network, and was trained using the vanilla policy gradient update algorithm. After the training, the agent’s ability to accurately locate the position of the focal depth and scanning plane improved. Our preliminary results confirmed that deep reinforcement learning can be applied to the ultrasound environment.

Keywords:
ultrasound guidance, reinforcement learning, deep learning

137.Szolc T., Konowrocki R., Pochanke A., On dynamic interaction between mechanical systems and selected electric motors, DYNKON 2019, 16th Symposium of Structural Dynamics , 2019-05-22/05-24, Kombornia, Poland (PL), DOI: 10.1051/matecconf/201928500018, Vol.285, pp.00018-1-8, 2019
Szolc T., Konowrocki R., Pochanke A., On dynamic interaction between mechanical systems and selected electric motors, DYNKON 2019, 16th Symposium of Structural Dynamics , 2019-05-22/05-24, Kombornia, Poland (PL), DOI: 10.1051/matecconf/201928500018, Vol.285, pp.00018-1-8, 2019

Abstract:
In the paper there is presented a reliable structural model of the rotating mechanical systems as well as mathematical models of the stepping, synchronous and asynchronous motors, by means of which electromechanical coupling effects can be thoroughly investigated. An
importance and severity of these phenomena, not sufficiently explored till present, have been demonstrated by results obtained for transient and steady-state operational conditions in the computational examples concerning torsional vibrations of drive trains with various electric motors.

Keywords:
structural model, electric motors, mechanical systems, electromechanical coupling

138.Szolc T., Falkowski K., The design of a combined, self-stabilizing electrodynamic passive magnetic bearing supporting high-speed rotors, SIRM 2019, 13th International Conference - DYNAMICS OF ROTATING MACHINERY, 2019-02-13/02-15, Copenhagen (DK), pp.272-281, 2019
Szolc T., Falkowski K., The design of a combined, self-stabilizing electrodynamic passive magnetic bearing supporting high-speed rotors, SIRM 2019, 13th International Conference - DYNAMICS OF ROTATING MACHINERY, 2019-02-13/02-15, Copenhagen (DK), pp.272-281, 2019

Abstract:
The purpose of this paper is to create a concept of the structurally simple and operationally robust support of high-speed rotors in the electrodynamic passive magnetic bearings (EDPMB). Since this kind of a magnetic suspension in its fundamental version is dynamically unstable, in order to avoid such an essential disadvantage there is proposed the addition of external damping by the use of the newly designed combined, self-stabilizing electrodynamic passive magnetic bearing. The electromagnetic stiffness- and damping characteristics of the combined EDPMB have been determined for various shaft rotational speeds by means of the advanced 3D finite element method. The dynamic investigations are performed for a single-span, high-speed flexible rotor-shaft. In the computational part a dynamic interaction between the rotor-shaft and the passive magnetic suspension is carried out for a support in the fundamental EDPMBs and in the proposed combined, self-stabilizing passive magnetic bearings. Here, the main attention is focused on asymptotic stability of the both rotor-shaft suspension variants. In addition, for the considered rotor-shaft-bearing system amplitude-frequency characteristics of forced steady-state bending vibrations have been determined. By means of this investigation there is demonstrated a resonance suppression ability using the external damping generated by the proposed combined EDPMBs.

Keywords:
magnetic bearing, electrodynamic passive magnetic bearings, EDPMB, rotor-shaft suspension, high-speed rotors

139.Walenta Z.A., Słowicka A.M., Optimization of Detonation Dampers for Ducts Transporting Gaseous Fuels, ISSW32, 32nd International Symposium on Shock Waves, 2019-07-14/07-19, Singapore (SG), pp.547-555, 2019
Walenta Z.A., Słowicka A.M., Optimization of Detonation Dampers for Ducts Transporting Gaseous Fuels, ISSW32, 32nd International Symposium on Shock Waves, 2019-07-14/07-19, Singapore (SG), pp.547-555, 2019

Abstract:
One of the important contemporary technological problems is connected withnecessity of extinguishing detonations, which may occur inpipelines transporting gaseousfuels. To achieve this goal usually a matrix of narrow channels is placed across the flowinside the pipeline. In our recent papers [1], [2] we have shown, that channels with sharpchanges of cross-section should be more efficient in this respect than traditionally usedstraight channels with constant cross-section area. In the present paper we demonstratehow detonation behaves in channels with changes of cross-section under realistic conditions– if the channel cross-section is of dimensions acceptable technologically. At the same timewe take into account the fact, that if friction and heat exchange at the walls are present,gas flowing through the channels accelerates and its densitydecreases considerably. Theresult of our considerations is a selection of, possibly, optimum shape of the channels ofa detonation damper.

140.Postek E., Sadowski T., Impact model of two-phase composites, DynaMAT, The 13th WORKSHOP on DYNAMIC BEHAVIOR OF MATERIALS AND ITS APPLICATIONS IN INDUSTRIAL PROCESSES, 2019-04-17/04-19, Nicosia (CY), pp.1-2, 2019
Postek E., Sadowski T., Impact model of two-phase composites, DynaMAT, The 13th WORKSHOP on DYNAMIC BEHAVIOR OF MATERIALS AND ITS APPLICATIONS IN INDUSTRIAL PROCESSES, 2019-04-17/04-19, Nicosia (CY), pp.1-2, 2019

Abstract:
Assessment of impact techniques is given in [1]. A basic model of a two-phase material is
presented in [2]. Two-phase composites are of vital applications in modern technology, for example
cutting tools, implants, jet engines. Examples of such materials are WC/Co and Al2O3/ZrO2. Highly
innovative technologies need applications of modern polycrystalline materials. The manufactured
polycrystalline materials are planned to have controlled internal structure. However, even though
the process is controlled the internal structure can be still complex due to engineering requirements.
The novel multiphase materials possess different internal geometries, for example (i) with regular of disordered internal structures with introduced fibers, particles or nanoparticles (ii) with a functional
gradation of mechanical or physical properties (iii) fabricated as regular of irregular layered materials
structures.
The analyses of modern composites require efficient computational methods and codes. The new
method that has been developed mostly in the last ten years is peridynamics [3,4]. The
developments resulted in a highly parallelised code [5] that we use in our analysis.
We further investigate the model of cermet that has been developed with the finite element method
[6, 7, 8]. The primary goal of the paper is to investigate the previously formulated models of the twophase
composite under impacts. We have taken into account the spatial distribution of cermet
phases, grain/binder interfaces modelled by interface elements and movement of brittle grains.
We analyse a sample of the material that can be considered as Representative Volume Element RVE
and do verification of the material properties of the RVE by multiplication of the elementary sample
with complex geometry [9].
In Fig. 1, we illustrate an outline of the analysis. It is an Al2O3/ZrO2 polycrystal that hits a rigid
obstacle with a velocity V. In this case, the velocity of the impactor is 100 m/s. We observe the
damage development in the interfaces calculated with finite element and PD methods at time 10 ns.
Further on, we consider damage models [10], elastic-plastic [11] and elastic-viscous-plastic models
[12].
References
[1] L. Kärger, J. Baaran, A. Gunnion, R. Thomson, Evaluation of impact assessment methodologies.
Part II: Experimental validation Composites: Part B, 40, (2009) pp. 71-76.
[2] E. Postek, T. Sadowski, Qualitative comparison of dynamic compressive pressure load and impact
of WC/Co composite, Int. J. Refract. Met. H, 77 (2018) pp. 68-81.
[3] S. A. Silling. Reformulation of elasticity theory for discontinuities and long‐range forces. Journal of
the Mechanics and Physics of Solids,48 (2000), pp. 175-209.
[4] A. Silling, M. Epton, O. Weckner, J. Xu, and E. Askari, Peridynamic states and constitutive
modeling, Journal of Elasticity, 88 (2007), pp. 151-184.
[5] M.L. Parks, D.J. Littlewood, J.A. Mitchell, and S.A. Silling, Peridigm Users’ Guide, Tech. Report
SAND2012-7800, Sandia National Laboratories, 2012.
[6] T. Sadowski , S. J. Hardy, E. Postek, Prediction of the mechanical response of polycrystalline
ceramics containing metallic intergranular layers under uniaxial tension. Comput. Mat. Sci, 34 (2005),
pp. 46-63.
[7] Postek E, Sadowski T. Assessing the Influence of Porosity in the Deformation of Metal-Ceramic
Composites. Comp. Interf, 18 (2011), pp. 57-76.
[8] Postek E, Sadowski T., Impact model of WC/Co composite, Comp. Struct, 213 (2019), pp. 231-242.
[9] S. Nemat-Nasser, M. Horii, Micromechanics: overall properties of the heterogeneous materials,
Amsterdam – New York – Oxford – Tokyo, Elsevier, 1999.
[10] M. Kachanov, Elastic solids with many cracks and related problems, Advances in Appl. Mech. 30
(1993), pp. 259-445.
[11] R. Hill, The Mathematical Theory of Plasticity. Oxford University Press: Oxford, 1998.
[12] O.C. Zienkiewicz, I. Cormeau, Visco-plasticity-Plasticity and creep in elastic solids–A unified
Numerical solution approach, Int. J. Numer. Meth. Eng, 8 (1974), pp. 821-845.

Keywords:
two phase composites, damage, elasoplasticity, impact, peridynamics

141.Manecka A., Pęcherski R., Ocena stateczności sprężystej nanopręta z uwzględnieniem efektu skali, OMIS 2019, XIII Konferencja Naukowa Odkształcalność Metali i Stopów, 2019-11-19/11-22, Łańcut (PL), pp.32-33, 2019
142.Manecka A., Ocena stateczności sprężystej nanopręta z uwzględnieniem efektu skali, XIII NKRM 2019, XIII Konferencja Nowe Kierunki Rozwoju Mechaniki, 2019-03-20/03-23, Będlewo (PL), pp.49-51, 2019
143.Lumelskyj D., Rojek J., Lazarescu L., Banabic D., Determination of forming limit curve by finite element method simulations, ICAFT/SFU/AutoMetForm 2018, 6th International Conference on Accuracy in Forming Technology, 25th Saxon Conference on Forming Technology and 6th International Lower Silesia-Saxony Conference on Advanced Metal Forming Processes in the Automotive Industry , 2018-11-06/11-07, Chemnitz (DE), DOI: 10.1016/j.promfg.2018.12.047, Vol.27, pp.78-82, 2019
Lumelskyj D., Rojek J., Lazarescu L., Banabic D., Determination of forming limit curve by finite element method simulations, ICAFT/SFU/AutoMetForm 2018, 6th International Conference on Accuracy in Forming Technology, 25th Saxon Conference on Forming Technology and 6th International Lower Silesia-Saxony Conference on Advanced Metal Forming Processes in the Automotive Industry , 2018-11-06/11-07, Chemnitz (DE), DOI: 10.1016/j.promfg.2018.12.047, Vol.27, pp.78-82, 2019

Abstract:
This paper presents an investigation on the determination of forming limit curves (FLCs) by finite element simulations. The numerical FLCs are determined applying the criteria of strain localization in simulations of the Nakazima formability tests. Two methods to determine the onset of localized necking have been compared. The first criterion is based on the analysis of the through-thickness thinning (through-thickness strain) and its first time derivative in the most strained zone. The onset of necking is assumed to occur at the point corresponding to a sudden change of the slope of the strain rate vs. time curve. The limit strain in the second method is determined by the maximum of the strain acceleration, which corresponds to the inflection point of the strain velocity vs. time curve. The limit strains have been determined for different specimens undergoing deformation at different strain paths covering the whole range of the strain paths typical for sheet forming processes. This has made it possible to construct numerical forming limit curves (FLCs). The numerical FLCs have been compared with the experimental one, showing quite a good agreement, especially in the case of the first criterion. This shows that finite element simulations can be used as a potential alternative tool to determine formability limits for sheet forming processes.

Keywords:
Sheet metal forming,Formability,Forming limit curve,Finite element simulation

144.Fura Ł., Dera W., Dziekoński C., Kujawska T., Evaluation of influence of ultrasound exposure parameters on necrotic lesions induced in tissues by robotic ultrasound-guided HIFU ablation device, 2019 ICU Bruges, 2019 International Congress on Ultrasonics, 2019-09-03/09-06, Bruges (BE), pp.1, 2019
145.Rojek J., Madan N., Nosewicz S., A novel formulation of the discrete element method with deformable particles, 12HSTAM 2019, International Congress on Mechanics, 2019-09-22/09-25, Thessaloniki (GR), pp.59-59, 2019
146.Rojek J., Madan N., Nosewicz S., The discrete element method with deformable particles, PCM-CMM, 4th Polish Congress of Mechanics, 23rd International Conference on Computer Methods in Mechanics, 2019-09-08/09-12, Kraków (PL), pp.1-1, 2019
Rojek J., Madan N., Nosewicz S., The discrete element method with deformable particles, PCM-CMM, 4th Polish Congress of Mechanics, 23rd International Conference on Computer Methods in Mechanics, 2019-09-08/09-12, Kraków (PL), pp.1-1, 2019

Keywords:
Discrete Element Method, Deformable Particles, Macroscopic Properties

147.Madan N., Rojek J., Nosewicz S., Enhanced wave propagation modelling capabilities of discrete element method using deformable elements, PCM-CMM, 4th Polish Congress of Mechanics, 23rd International Conference on Computer Methods in Mechanics, 2019-09-08/09-12, Kraków (PL), pp.1-1, 2019
Madan N., Rojek J., Nosewicz S., Enhanced wave propagation modelling capabilities of discrete element method using deformable elements, PCM-CMM, 4th Polish Congress of Mechanics, 23rd International Conference on Computer Methods in Mechanics, 2019-09-08/09-12, Kraków (PL), pp.1-1, 2019

Keywords:
Elastic Wave Propagation, Deformability, Discrete Element Method

148.Rojek J., Madan N., Nosewicz S., Simulation of elastic wave propagation using the deformable discrete element method, KomPlasTech 2019, Computer Methods in Materials Technology, 2019-01-13/01-16, Zakopane (PL), pp.106-107, 2019
Rojek J., Madan N., Nosewicz S., Simulation of elastic wave propagation using the deformable discrete element method, KomPlasTech 2019, Computer Methods in Materials Technology, 2019-01-13/01-16, Zakopane (PL), pp.106-107, 2019

Keywords:
wave propagation, elasticity, discrete element method,simulation

149.Marijnissen M.J., Graczykowski C., Rojek J., Computational Fluid Dynamics and Discrete Element Method coupling utilized for the simulation of particle comminution in newly designed beater mills, COUPLED 2019, VIII International Conference on Coupled Problems in Science and Engineering, 2019-06-03/06-05, Sitges (ES), pp.1, 2019
150.Marijnissen M.J., Graczykowski C., Rojek J., Two-stage CFD-DEM (Computational Fluid Dynamics – Discrete Element Method) approach for the simulation of particle comminution inside a beater mill, YIC2019, 5th ECCOMAS Young Investigators Conference, 2019-09-01/09-06, Kraków (PL), pp.1-2, 2019
151.Burczyński T., Kuś W., Maździarz M., Mrozek A., Molecular and Ab-initio Approaches in Computational Design of New 2D Nano-Structures, COUPLED 2019, VIII International Conference on Coupled Problems in Science and Engineering, 2019-06-03/06-05, Sitges (ES), pp.1, 2019
152.Kuś W., Akhter M.J., Mrozek A., Burczyński T., The influence of defects on mechanical properties in molybdenum disulfide flat material, KOMPLASTECH 2019, XXVI CONFERENCE ON COMPUTER METHODS IN MATERIALS TECHNOLOGY, 2019-01-13/01-16, Zakopane (PL), pp.1-2, 2019
153.Mrozek A., Kuś W., Burczyński T., Bioinspired optimization of mechanical properties of two-phase single-layered mos2 structures, PCM-CMM, 4th Polish Congress of Mechanics, 23rd International Conference on Computer Methods in Mechanics, 2019-09-08/09-12, Kraków (PL), pp.1, 2019
154.Burczyński T., Kuś W., Maździarz M., Mrozek A., Computational intelligence in design of new nanomaterials, Computational Sciences and AI in Industry, 2019-06-12/06-14, Jyvaskyla (FI), pp.1, 2019
155.Burczyński T., Maździarz M., Mrozek A., Kuś W., Designing of new 2d semiconducting carbon allotrope as an inverse problem, IPM 2019, 5th ECCOMAS Thematic Conference on Inverse Problems Methods, 2019-05-22/05-24, Rzeszów-Kombornia (PL), pp.1-2, 2019
156.Kuś W., Akhter M.J., Mrozek A., Burczyński T., Bioinspired optimization of mos2 2d material with presence of defects, PCM-CMM, 4th Polish Congress of Mechanics, 23rd International Conference on Computer Methods in Mechanics, 2019-09-08/09-12, Kraków (PL), pp.1, 2019
157.Burczyński T., Kuś W., Mrozek A., Optimization of 2D materials based on Molybdenum, CNM 2019, 6th CONFERENCE ON NANO- AND MICROMECHANICS, 2019-07-03/07-05, Rzeszów (PL), pp.1-2, 2019
158.Opara K., Zieliński J., Brzeziński K., Kaczmarek-Majer K., Bukowicki M., Evaluation of pavement roughness through vehicle vibration monitoring, 26th World Road Congress, 2019-10-06/10-10, Abu Dhabi (AE), pp.1-15, 2019
Opara K., Zieliński J., Brzeziński K., Kaczmarek-Majer K., Bukowicki M., Evaluation of pavement roughness through vehicle vibration monitoring, 26th World Road Congress, 2019-10-06/10-10, Abu Dhabi (AE), pp.1-15, 2019

Abstract:
Driving on uneven roads causes vibrations of the vehicle. Modern smartphones are equipped with accelerometers and gyroscopes which allow for inexpensive acquisition of information about the shaking level. This study reports on field tests of a system, which measures vibrations of a driving vehicle using four smartphones as sensors. The collected data undergo a series of processing steps, namely synchronization, virtual reorientation, temporal and spectral filtering, and assignment of road localization. We use quarter-car and half-car suspension models to retrieve the longitudinal road profile and to compute unevenness indicators. The accuracy of the system was computed by comparison with traditional laser profilometer on an 18.6 km long test section using eight rides with different speeds. It averages to 71% and exceeds 80% for the best calibrated cases. Additionally, we report on the feedback obtained during tests of the system in a district road administration in Poland.

159.Klimonda Z., Karwat P., Dobruch-Sobczak K., Piotrzkowska-Wróblewska H., Litniewski J., Assessment of a breast cancer response to neoadjuvant chemotherapy using backscatter ultrasound statistics, 2019 ICU Bruges, 2019 International Congress on Ultrasonics, 2019-09-03/09-06, Bruges (BE), DOI: 10.1121/2.0001104, Vol.38, No.1, pp.020003-1-5, 2019
160.Wójcik J., Secomski W., Żołek N., The Forces Driving Streaming in the Presence of Scatterers Mimicking the Blood Cells and the Contrast Agents , IFA2019, International Symposium on Fluid Acoustics IFA2019 Sopot, Poland, May 20–22, 2019, 2019-05-20/05-22, Sopot (PL), DOI: 10.24425/aoa.2019.128504, Vol.44, No.2, pp.414, 2019
Wójcik J., Secomski W., Żołek N., The Forces Driving Streaming in the Presence of Scatterers Mimicking the Blood Cells and the Contrast Agents , IFA2019, International Symposium on Fluid Acoustics IFA2019 Sopot, Poland, May 20–22, 2019, 2019-05-20/05-22, Sopot (PL), DOI: 10.24425/aoa.2019.128504, Vol.44, No.2, pp.414, 2019

Abstract:
Acoustical Driving Forces (ADF), induced by propagating waves in a homogeneous and inhomogeneous lossy fluid (suspension), are determined and compared depending on the concentration of suspended particles. Using integral equations of the scattering theory, the single particle (inclusion) ADF was calculated as the integral of the flux of the momentum density tensor components over the heterogeneity surface. The possibility of negative ADF was indicated. Originally derived, the total ADF acting on inclusions only, stochastically distributed in ambient fluid, was determined as a function of its concentration. The formula for the relative increase in ADF, resulting from increased concentration was derived. Numerical ADF calculations are presented. In experiments the streaming velocities in a blood-mimicking starch suspension (2 mu m radius) in water and Bracco BR14 contrast agent (SF6 gas capsules, 1 mu m radius) were measured as the function of different inclusions concentration. The source of the streaming and ADF was a plane 2 mm diameter 20 MHz ultrasonic transducer. Velocity was estimated from the averaged Doppler spectrum obtained from originally developed pulsed Doppler flowmeter. Numerical calculations of the theoretically derived formula showed very good agreement with the experimental results.

161.Urbanek-Świderska O., Kołbuk D., Designing of Three-Dimensional Hybrid Scaffolds for Tissue Regeneration, 2019 MRS FALL MEETING & EXHIBIT, 2019-12-01/12-06, Boston (US), pp.1659, 2019
162.Kołbuk-Konieczny D., Urbanek-Świderska O., Jeznach O., Hybrid scaffold to anterior cruciate ligament regeneration, TERMIS EU 2019, TERMIS European Chapter Meeting 2019, Tissue Engineering Therapies: From Concept to Clinical Translation & Commercialisation, 2019-05-27/05-31, Rodos (GR), pp.1461, 2019
163.Karwat P., Computationally efficient algorithm for sound speed imaging in pulse-echo ultrasound, 2019 ICU Bruges, 2019 International Congress on Ultrasonics, 2019-09-03/09-06, Bruges (BE), DOI: 10.1121/2.0001109, Vol.38, No.1, pp.020005-1-6, 2019
Karwat P., Computationally efficient algorithm for sound speed imaging in pulse-echo ultrasound, 2019 ICU Bruges, 2019 International Congress on Ultrasonics, 2019-09-03/09-06, Bruges (BE), DOI: 10.1121/2.0001109, Vol.38, No.1, pp.020005-1-6, 2019

Abstract:
Precise information about the spatial distribution of sound speed in tissue has diagnostic value in itself, and also enables effective aberration correction in standard ultrasonic imaging. An algorithm called Computed Ultrasound Tomography in Echo mode (CUTE) makes it possible to reconstruct quantitative sound speed images. However, the computational cost is high, which is an obstacle to CUTE implementation in real-time imaging systems. This paper presents an improved version of the CUTE algorithm called Quick-CUTE (Q-CUTE). The CUTE algorithm uses the inverse transformation matrix to reconstruct the sound speed spatial distribution. The Q-CUTE algorithm is based on simplified model with unified integration paths which enables solving the inverse problem without use of a large transformation matrix. The Q-CUTE algorithm was verified through numerical simulations. The obtained results differ from those of the CUTE algorithm but maintain the quantitative character of sound speed imaging. The computational complexity of the Q-CUTE algorithm is proportional to N while in case of the CUTE it is proportional to N squared (where N is a number of pixels in the sound speed image). This means that the Q-CUTE algorithm allows the quantitative sound speed imaging to operate in real time.

164.Byra M., Galperin M., Ojeda-Fournier H., Olson L., O Boyle M., Comstock C., Andre M., Comparison of deep learning and classical breast mass classification methods in ultrasound, ASA, 178th Meeting of the Acoustical Society of America, 2019-12-02/12-06, San Diego (US), DOI: 10.1121/1.5136937, Vol.146, No.4, pp.2864-1, 2019
Byra M., Galperin M., Ojeda-Fournier H., Olson L., O Boyle M., Comstock C., Andre M., Comparison of deep learning and classical breast mass classification methods in ultrasound, ASA, 178th Meeting of the Acoustical Society of America, 2019-12-02/12-06, San Diego (US), DOI: 10.1121/1.5136937, Vol.146, No.4, pp.2864-1, 2019

Abstract:
We developed breast mass classification methods based on deep convolutional neural networks (CNNs) and morphological features (MF), then compared those to assessment of four experienced radiologists employing BI-RADS protocol. The classification models were developed based on 882 clinical ultrasound B-mode images of masses with confirmed findings and regions of interest indicating mass areas. Various transfer learning techniques, including fine-tuning of a pre-trained CNN, were investigated to develop deep learning models. A matching layer technique was applied to convert gray-scale images to red, green, blue to efficiently utilize discrimination of the pre-trained model. For the classical approach, we calculated MF related to breast mass shape (e.g., height-width ratio, circularity) and then trained binary classifiers. We additionally evaluated both approaches using two publicly available US datasets. Several statistical measures (area under the receiver operating curve [AUC], sensitivity and specificity) were used to assess the classification performance on a test set of 150 cases. The matching layer significantly increased AUC from 0.895 to 0.936 while radiologists’ AUCs ranged from 0.806 to 0.882. This study shows both deep learning and classical models achieve high performance. When developed as a clinical tool, the methods examined in this study have potential to aid radiologists accurate breast mass classification with ultrasound.

165.Byra M., Han A., Boehringer A., Zhang Y., Erdman J., Loomba R., Valasek M., Sirlin C., O Brien W., Andre M., Quantitative liver fat fraction measurement by multi-view sonography using deep learning and attention maps, ASA, 178th Meeting of the Acoustical Society of America, 2019-12-02/12-06, San Diego (US), DOI: 10.1121/1.5136936, Vol.146, No.4, pp.2809-1, 2019
Byra M., Han A., Boehringer A., Zhang Y., Erdman J., Loomba R., Valasek M., Sirlin C., O Brien W., Andre M., Quantitative liver fat fraction measurement by multi-view sonography using deep learning and attention maps, ASA, 178th Meeting of the Acoustical Society of America, 2019-12-02/12-06, San Diego (US), DOI: 10.1121/1.5136936, Vol.146, No.4, pp.2809-1, 2019

Abstract:
Qualitative sonography is used to assess nonalcoholic fatty liver disease (NAFLD), an important health issue worldwide. We used B-mode image deep-learning to objectively assess NAFLD in 4 views of the liver (hepatic veins at confluence with inferior vena cava, right portal vein, right posterior portal vein and liver/kidney) in 135 patients with known or suspected NAFLD. Transfer learning with a deep convolutional neural network (CNN) was applied for quantifying fat fraction and diagnosing fatty liver (≥ 5%) using contemporaneous MRI-PDFF as ground truth. Single and multi-view learning approaches were compared. Class activation mapping generated attention maps to highlight regions important for deep learning-based recognition. The most accurate single view was hepatic veins, with area under the receiver operating characteristic curve (AUC) of 0.86 and Spearman’s rank correlation coefficient of 0.65. A multi-view ensemble of deep-learning models trained for each view separately improved AUC (0.93) and correlation coefficient (0.76). Attention maps highlighted regions known to be used by radiologists in their qualitative assessment, e.g., hepatic vein-parenchyma interface and liver-kidney interface. Machine learning of four liver views can automatically and objectively assess liver fat. Class activation mapping suggests that the CNN focuses on similar features as radiologists. [No. R01DK106419.]

166.Byra M., Wong J., Shah S., Han A., O Brien W., Du J., Chang E., Andre M., High-frequency quantitative ultrasound and B-mode analysis for characterization of peripheral nerves including carpal tunnel syndrome, ASA, 178th Meeting of the Acoustical Society of America, 2019-12-02/12-06, San Diego (US), DOI: 10.1121/1.5136729, Vol.146, No.4, pp.2809-2809, 2019
Byra M., Wong J., Shah S., Han A., O Brien W., Du J., Chang E., Andre M., High-frequency quantitative ultrasound and B-mode analysis for characterization of peripheral nerves including carpal tunnel syndrome, ASA, 178th Meeting of the Acoustical Society of America, 2019-12-02/12-06, San Diego (US), DOI: 10.1121/1.5136729, Vol.146, No.4, pp.2809-2809, 2019

Abstract:
We investigated the use of high-frequency quantitative ultrasound (QUS) and B-mode texture features to characterize ulnar and median nerve fascicles using a clinical scanner (Vevo MD) and a 30-MHz center-frequency probe. US correlation with histology was first investigated in the ulnar nerve in situ in cadaveric specimens. 85 fascicles were matched in B-mode images and the histology sections. Collagen and myelin concentrations were quantified from trichrome labeling, and backscatter coefficient (-24.89 ± 8.31 dB), attenuation coefficient (0.92 ± 0.04 dB/cm MHz), Nakagami parameter (1.01 ± 0.18) and entropy (6.92 ± 0.83) were calculated from ultrasound data. B-mode texture features were obtained via the gray-level co-occurrence matrix algorithm. Combined collagen and myelin concentration were significantly correlated with the backscatter coefficient (R = -0.68), entropy (R = -0.51), and several texture features. For the median nerve, we measured backscatter and morphology in 10 patients with carpal tunnel syndrome and 21 healthy volunteers. Significant differences (<0.01) between patients and controls and AUC 0.89–0.94 for QUS biomarkers were observed. Our study indicates that QUS may potentially provide useful information on structural components of even very small nerves (2 × 4 mm) and fascicles for diagnosing and monitoring injury, and surgical planning.

167.Kowalczyk T., Niemczyk B., Kloskowski T., Jundziłł A., Adamowicz J., Nowacki M., Pokrywczyńska M., Noszczyk B., Drewa T., Investigation of the in vivo behavior of membranes made of electrospun micro and nanofibers implanted on an animal model, CNM 2019, 6th CONFERENCE ON NANO- AND MICROMECHANICS, 2019-07-03/07-05, Rzeszów (PL), pp.137-139, 2019
Kowalczyk T., Niemczyk B., Kloskowski T., Jundziłł A., Adamowicz J., Nowacki M., Pokrywczyńska M., Noszczyk B., Drewa T., Investigation of the in vivo behavior of membranes made of electrospun micro and nanofibers implanted on an animal model, CNM 2019, 6th CONFERENCE ON NANO- AND MICROMECHANICS, 2019-07-03/07-05, Rzeszów (PL), pp.137-139, 2019

Keywords:
electrospinning, microfibers, nanofibers, in vivo, animal model

168.Saghazadeh S., Rinoldi C., Schot M., Kashaf S.S., Sharifi F., Jalilian E., Nuutila K., Giatsidis G., Mostafalu P., Derakhshandeh H., Yue K., Święszkowski W., Memic A., Tamayol A., Khademhosseini A., Drug delivery systems and materials for wound healing applications, Advanced Drug Delivery Reviews, ISSN: 0169-409X, DOI: 10.1016/j.addr.2018.04.008, Vol.127, pp.138-166, 2018
Saghazadeh S., Rinoldi C., Schot M., Kashaf S.S., Sharifi F., Jalilian E., Nuutila K., Giatsidis G., Mostafalu P., Derakhshandeh H., Yue K., Święszkowski W., Memic A., Tamayol A., Khademhosseini A., Drug delivery systems and materials for wound healing applications, Advanced Drug Delivery Reviews, ISSN: 0169-409X, DOI: 10.1016/j.addr.2018.04.008, Vol.127, pp.138-166, 2018

Abstract:
Chronic, non-healing wounds place a significant burden on patients and healthcare systems, resulting in impaired mobility, limb amputation, or even death. Chronic wounds result from a disruption in the highly orchestrated cascade of events involved in wound closure. Significant advances in our understanding of the pathophysiology of chronic wounds have resulted in the development of drugs designed to target different aspects of the impaired processes. However, the hostility of the wound environment rich in degradative enzymes and its elevated pH, combined with differences in the time scales of different physiological processes involved in tissue regeneration require the use of effective drug delivery systems. In this review, we will first discuss the pathophysiology of chronic wounds and then the materials used for engineering drug delivery systems. Different passive and active drug delivery systems used in wound care will be reviewed. In addition, the architecture of the delivery platform and its ability to modulate drug delivery are discussed. Emerging technologies and the opportunities for engineering more effective wound care devices are also highlighted.

Keywords:
Wound healing, Drug delivery, Transdermal delivery, Microtechnologies, Nanotechnologies

169.Azevedo Moreira R., Energy Gaps of Polyradicals from an Effective and Transferable Hamiltonian with through-Bond Interactions, Journal of Chemical Theory and Computation, ISSN: 1549-9618, DOI: 10.1021/acs.jctc.7b00930, Vol.14, No.1, pp.1-8, 2018
Azevedo Moreira R., Energy Gaps of Polyradicals from an Effective and Transferable Hamiltonian with through-Bond Interactions, Journal of Chemical Theory and Computation, ISSN: 1549-9618, DOI: 10.1021/acs.jctc.7b00930, Vol.14, No.1, pp.1-8, 2018

Abstract:
Current model Hamiltonians and ab initio manybody quantum treatments of π-conjugated polyradicals formed from hydrocarbons produce divergent results because of numerical complexity and large size of the basis-function set used. We propose an alternative, three-term Hamiltonian, to describe these various polyradicals that simplifies considerably the computational cost while providing a physical interpretation for all three terms and a high degree of model universality. The essential feature of this Hamiltonian is a term, not present in previous models, describing the three-sited through-bond interaction that governs the noninteracting spin-up and spin-down sectors. A computation of the lowest energy gaps and spin configurations for the smaller polyradicals demonstrates the efficacy of the model and its potential in applications in revealing electrical conductivity and ferromagnetism of the more complicated substituted polyradicals.

170.Chlanda A., Kijeńska E., Rinoldi C., Tarnowski M., Wierzchoń T., Święszkowski W., Structure and physico-mechanical properties of low temperature plasma treated electrospun nanofibrous scaffolds examined with atomic force microscopy, Micron, ISSN: 0968-4328, DOI: 10.1016/j.micron.2018.01.012, Vol.107, pp.79-84, 2018
Chlanda A., Kijeńska E., Rinoldi C., Tarnowski M., Wierzchoń T., Święszkowski W., Structure and physico-mechanical properties of low temperature plasma treated electrospun nanofibrous scaffolds examined with atomic force microscopy, Micron, ISSN: 0968-4328, DOI: 10.1016/j.micron.2018.01.012, Vol.107, pp.79-84, 2018

Abstract:
Electrospun nanofibrous scaffolds are willingly used in tissue engineering applications due to their tunable mechanical, chemical and physical properties. Additionally, their complex openworked architecture is similar to the native extracellular matrix of living tissue. After implantation such scaffolds should provide sufficient mechanical support for cells. Moreover, it is of crucial importance to ensure sterility and hydrophilicity of the scaffold. For this purpose, a low temperature surface plasma treatment can be applied. In this paper, we report physico-mechanical evaluation of stiffness and adhesive properties of electrospun mats after their exposition to low temperature plasma. Complex morphological and mechanical studies performed with an atomic force microscope were followed by scanning electron microscope imaging and a wettability assessment. The results suggest that plasma treatment can be a useful method for the modification of the surface of polymeric scaffolds in a desirable manner. Plasma treatment improves wettability of the polymeric mats without changing their morphology.

Keywords:
Atomic force microscopy, Surface modification, Electrospun fibers, RF plasma treatment, Tissue engineering, Nanomaterial

171.Szymczak T., Brodecki A., Kowalewski Z.L., Lasota P., Ocena trwałości zmęczeniowej końcówki drążka kierowniczego, TRANSPORT SAMOCHODOWY, ISSN: 1731-2795, Vol.2, pp.63-72, 2018
Szymczak T., Brodecki A., Kowalewski Z.L., Lasota P., Ocena trwałości zmęczeniowej końcówki drążka kierowniczego, TRANSPORT SAMOCHODOWY, ISSN: 1731-2795, Vol.2, pp.63-72, 2018

Abstract:
W pracy zaprezentowano wyniki badań trwałościowych końcówki drążka kierowniczego pojazdu o dmc powyżej 3.5 tony. W badaniach wykorzystywano wielkogabarytową platformę wibroizolowaną, serwohydrauliczny siłownik mobilny oraz cyfrowy kontroler sygnałów IST Instron. Próby prowadzono w warunkach działania obciążenia zmiennego cyklicznie do uzyskania 2×106 cykli. Ze względu na kompleksową ocenę zachowania końcówki drążka kierowniczego testy przerywano, by wykonywać oględziny obiektu badań. Wyznaczono zmiany kąta wychylenia oraz momentu siły w funkcji liczby cykli oraz przedstawiono ich prognozę. Omówiono procedurę badawczą służącą ocenie trwałości przegubu kulistego.

Keywords:
przegub, zmęczenie, obciążenie zmienne cyklicznie, liczba cykli, trwałość, pęknięcie

172.Rinoldi C., Kijeńska E., Chlanda A., Choinska E., Khenoussi N., Tamayol A., Khademhosseini A., Święszkowski W., Nanobead-on-string composites for tendon tissue engineering, JOURNAL OF MATERIALS CHEMISTRY B , ISSN: 2050-7518, DOI: 10.1039/c8tb00246k, Vol.6, No.19, pp.3116-3127, 2018
Rinoldi C., Kijeńska E., Chlanda A., Choinska E., Khenoussi N., Tamayol A., Khademhosseini A., Święszkowski W., Nanobead-on-string composites for tendon tissue engineering, JOURNAL OF MATERIALS CHEMISTRY B , ISSN: 2050-7518, DOI: 10.1039/c8tb00246k, Vol.6, No.19, pp.3116-3127, 2018

Abstract:
Tissue engineering holds great potential in the production of functional substitutes to restore, maintain or improve the functionality in defective or lost tissues. So far, a great variety of techniques and approaches for fabrication of scaffolds have been developed and evaluated, allowing researchers to tailor precisely the morphological, chemical and mechanical features of the final constructs. Electrospinning of biocompatible and biodegradable polymers is a popular method for producing homogeneous nanofibrous structures, which might reproduce the nanosized organization of the tendons. Moreover, composite scaffolds obtained by incorporating nanoparticles within electrospun fibers have been lately explored in order to enhance the properties and the functionalities of the pristine polymeric constructs. The present study is focused on the design and fabrication of biocompatible electrospun nanocomposite fibrous scaffolds for tendon regeneration. A mixture of poly(amide 6) and poly(caprolactone) is electrospun to generate constructs with mechanical properties comparable to that of native tendons. To improve the biological activity of the constructs and modify their topography, wettability, stiffness and degradation rate, we incorporated silica particles into the electrospun substrates. The use of nanosize silica particles enables us to form bead-on-fiber topography, allowing the better exposure of ceramic particles to better profit their beneficial characteristics. In vitro biocompatibility studies using L929 fibroblasts demonstrated that the presence of 20 wt% of silica nanoparticles in the engineered scaffolds enhanced cell spreading and proliferation as well as extracellular matrix deposition. The results reveal that the electrospun nanocomposite scaffold represents an interesting candidate for tendon tissue engineering.

173.Wojtacki K., Daridon L., Monerie Y., Computing the elastic properties of sandstone submitted to progressive dissolution, INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES, ISSN: 1365-1609, DOI: 10.1016/j.ijrmms.2016.12.015, Vol.95, pp.16-25, 2017
Wojtacki K., Daridon L., Monerie Y., Computing the elastic properties of sandstone submitted to progressive dissolution, INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES, ISSN: 1365-1609, DOI: 10.1016/j.ijrmms.2016.12.015, Vol.95, pp.16-25, 2017

Abstract:
We present a numerical method for estimating the stiffness-to-porosity relationships for evolving microstructures of Fontainebleau sandstone. The proposed study is linked to geological storage of CO 2 and focuses on long-term and far field conditions, when the progressive degradation of the porous matrix can be assumed to be homogeneous at the sample scale. The method is based on microstructure sampling with respect to morphological descriptors extracted from microtomography. First, an efficient method of generation of accurate numerical media is proposed. The method is based on grain deposit, compaction and diagenesis and allows to reproduce user-defined morphological parameters. Second, two simple numerical models that mimic chemical degradation of porous aquifers are presented. Effective elastic properties are estimated within the framework of periodic homogenization and finite element approach. A fixed-point method on a self-consisted outer layer allows to consider non-periodic representative volume elements. Accurate predictions of elastic properties over a wide range of porosity are obtained. The overall evolutions of elastic behaviour due to the increase of porosity are in excellent agreement both, with experimental data and the results obtained by Arns et al. [1].

Keywords:
Porous media, X-ray microtomography, Numerical dissolution, Fontainebleau sandstone, Self-consisted numerical method, Homogenization

174.Nasajpour A., Ansari S., Rinoldi C., Rad A.S., Aghaloo T., Shin S.R., Mishra Y.K., Adelung R., Święszkowski W., Annabi N., Khademhosseini A., Moshaverinia A., Tamayol A., A Multifunctional Polymeric Periodontal Membrane with Osteogenic and Antibacterial Characteristics, Advanced Functional Materials, ISSN: 1616-301X, DOI: 10.1002/adfm.201703437, Vol.28, No.3, pp.1703437-1-8, 2017
Nasajpour A., Ansari S., Rinoldi C., Rad A.S., Aghaloo T., Shin S.R., Mishra Y.K., Adelung R., Święszkowski W., Annabi N., Khademhosseini A., Moshaverinia A., Tamayol A., A Multifunctional Polymeric Periodontal Membrane with Osteogenic and Antibacterial Characteristics, Advanced Functional Materials, ISSN: 1616-301X, DOI: 10.1002/adfm.201703437, Vol.28, No.3, pp.1703437-1-8, 2017

Abstract:
Periodontitis is a prevalent chronic, destructive inflammatory disease affecting tooth‐supporting tissues in humans. Guided tissue regeneration strategies are widely utilized for periodontal tissue regeneration generally by using a periodontal membrane. The main role of these membranes is to establish a mechanical barrier that prevents the apical migration of the gingival epithelium and hence allowing the growth of periodontal ligament and bone tissue to selectively repopulate the root surface. Currently available membranes have limited bioactivity and regeneration potential. To address such challenges, an osteoconductive, antibacterial, and flexible poly(caprolactone) (PCL) composite membrane containing zinc oxide (ZnO) nanoparticles is developed. The membranes are fabricated through electrospinning of PCL and ZnO particles. The physical properties, mechanical characteristics, and in vitro degradation of the engineered membrane are studied in detail. Also, the osteoconductivity and antibacterial properties of the developed membrane are analyzed in vitro. Moreover, the functionality of the membrane is evaluated with a rat periodontal defect model. The results confirmed that the engineered membrane exerts both osteoconductive and antibacterial properties, demonstrating its great potential for periodontal tissue engineering.

Keywords:
electrospinning, guided tissue regeneration, osteoconductive, periodontal regeneration, zinc oxide

175.Tabin J., Skoczeń B., Bielski J., Damage affected discontinuous plastic flow (DPF), Mechanics od Materials, ISSN: 0167-6636, DOI: 10.1016/j.mechmat.2017.04.007, Vol.110, pp.44-58, 2017
Tabin J., Skoczeń B., Bielski J., Damage affected discontinuous plastic flow (DPF), Mechanics od Materials, ISSN: 0167-6636, DOI: 10.1016/j.mechmat.2017.04.007, Vol.110, pp.44-58, 2017

Abstract:
Evolution of micro-damage in the course of discontinuous plastic flow (DPF, serrated yielding) at extremely low temperatures is investigated. DPF is observed in many metals and alloys loaded in cryogenic conditions, within the temperature range specific of a given material and starting practically at absolute zero. The appearance of DPF is similar to dynamic strain ageing, however, its origin is attributed to the mechanism of local catastrophic failure of lattice barriers under the stress fields related to edge dislocation pile-ups. Failure of barriers, occurring in weakly excited lattice, leads to dynamic and massive motion of released dislocations. The phenomenon is accompanied by step-wise increase of the strain rate and drastic drop of stress during each serration. DPF has strong thermodynamic background consisting in the fact, that the plastic power dissipated in the course of serrations is partially converted to heat, which results in a local jump of temperature. It results from the so-called thermodynamic instability associated with vanishing specific heat when the temperature tends to absolute zero. The evolution of micro-damage affects loading and unloading moduli during each serration. This, in turn, results in gradual evolution of the amount of plastic slip accompanying each serration. The physically based constitutive model describes damage affected serrated yielding at the temperatures close to absolute zero. The model accounts for the thermodynamic background, including phonon mechanism of heat transport. Experimental identification of parameters of the constitutive model has been carried out based on a number of loading/unloading traction tests. A comparison between the experimental and the numerical results is presented and discussed.

Keywords:
Multiscale constitutive model, Discontinuous plastic flow, Microstructures radiation induced damage, Cryogenic temperatures

176.Celikkin N., Rinoldi C., Costantini M., Trombetta M., Rainer A., Święszkowski W., Naturally derived proteins and glycosaminoglycan scaffolds for tissue engineering applications, Materials Science and Engineering C-Materials for Biological Applications, ISSN: 0928-4931, DOI: 10.1016/j.msec.2017.04.016, Vol.78, pp.1277-1299, 2017
Celikkin N., Rinoldi C., Costantini M., Trombetta M., Rainer A., Święszkowski W., Naturally derived proteins and glycosaminoglycan scaffolds for tissue engineering applications, Materials Science and Engineering C-Materials for Biological Applications, ISSN: 0928-4931, DOI: 10.1016/j.msec.2017.04.016, Vol.78, pp.1277-1299, 2017

Abstract:
Tissue engineering (TE) aims to mimic the complex environment where organogenesis takes place using advanced materials to recapitulate the tissue niche. Cells, three-dimensional scaffolds and signaling factors are the three main and essential components of TE. Over the years, materials and processes have become more and more sophisticated, allowing researchers to precisely tailor the final chemical, mechanical, structural and biological features of the designed scaffolds. In this review, we will pose the attention on two specific classes of naturally derived polymers: fibrous proteins and glycosaminoglycans (GAGs). These materials hold great promise for advances in the field of regenerative medicine as i) they generally undergo a fast remodeling in vivo favoring neovascularization and functional cells organization and ii) they elicit a negligible immune reaction preventing severe inflammatory response, both representing critical requirements for a successful integration of engineered scaffolds with the host tissue. We will discuss the recent achievements attained in the field of regenerative medicine by using proteins and GAGs, their merits and disadvantages and the ongoing challenges to move the current concepts to practical clinical application.

Keywords:
Natural polymers, Hydrogel scaffolds, Glycosaminoglycans (GAGs), Fibrous proteins, Regenerative medicine

177.Azevedo Moreira R., de Melo C.P., Entanglement and Electronic Correlation in Polycyclic Aromatic Molecules, Brazilian Journal of Physics, ISSN: 0103-9733, DOI: 10.1007/s13538-017-0535-7, Vol.47, No.6, pp.575-582, 2017
Azevedo Moreira R., de Melo C.P., Entanglement and Electronic Correlation in Polycyclic Aromatic Molecules, Brazilian Journal of Physics, ISSN: 0103-9733, DOI: 10.1007/s13538-017-0535-7, Vol.47, No.6, pp.575-582, 2017

Abstract:
Based on the diagonalization of an effective Hamiltonian, we investigate the role of electronic correlation on the aromatic behavior of polycyclic aromatic hydrocarbons (PAHs). We show that for benzene and several examples of PAHs, a singular change in the electronic distribution happens at a relatively narrow range of the Coulomb interaction strength; in each case, the CC bond distribution pattern agrees with the known chemical behavior of the corresponding compound. We explore the link between electronic correlation and information entropy and show that several signatures of fluctuations in the one-particle entropy occur at the same range of values of the Coulomb parameter that correspond to a realistic bond-order distribution of the PAHs. These results indicate that the singular stability of the electronic distribution of aromatic compounds is associated with an optimum range of correlation effects, which can be understood in terms of the entanglement of the two sub-lattices of alternating carbon atoms and the presence of a localization transition of the overall electronic density.

Keywords:
Aromatic compounds, Model Hamiltonian, Exact diagonalization, Electronic correlation, Information entropy

178.Tabin J., Skoczeń B., Bielski J., Strain localization during discontinuous plastic flow at extremely low temperatures, INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, ISSN: 0020-7683, DOI: 10.1016/j.ijsolstr.2016.06.012, Vol.97-98, pp.593-612, 2016
Tabin J., Skoczeń B., Bielski J., Strain localization during discontinuous plastic flow at extremely low temperatures, INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, ISSN: 0020-7683, DOI: 10.1016/j.ijsolstr.2016.06.012, Vol.97-98, pp.593-612, 2016

Abstract:
The phenomenon of strain localization in the course of discontinuous plastic flow (DPF) at extremely low temperatures is investigated. DPF is observed mainly in fcc metals and alloys strained in cryogenic conditions, practically down to absolute zero. These materials undergo at low temperatures a process similar to dynamic strain ageing, manifested by the so called serrated yielding (DPF). DPF is attributed to the mechanism of local catastrophic failure of lattice barriers (including Lomer–Cottrell locks), under the stress fields related to the accumulating edge dislocations. Failure of LC locks leads to massive motion of released dislocations, accompanied by step-wise increase of the strain rate (macroscopic slip) and drastic drop of stress. Recent experiments indicate strong strain localization in the form of shear bands propagating along the sample. The plastic power dissipated in the shear band is partially converted to heat, which results in a local drastic increase of temperature promoted by the so-called thermodynamic instability (nearly adiabatic process). The Dirac-like temperature function is measured by two thermometers located in the gage length of the sample. Spatio-temporal correlation indicates smooth shear band propagation, as long as the process of phase transformation remains on hold. A physically based multiaxial constitutive model presented in the paper describes both DPF and strain localization, accompanied by temperature distribution represented by Green-like solution of heat diffusion equation. The model accounts for the thermodynamic background, including phonon mechanism of heat transport, accompanied by specific heat vanishing with the temperature approaching absolute zero. Experimental identification of parameters of the constitutive model is carried out. A projection of the model to the range where the phase transformation takes place is discussed.

Keywords:
Multiscale constitutive model, Discontinuous plastic flow, Cryogenic temperatures, Strain localization

179.Tabin J., Prącik M., Methods for identifying dynamic parameters of clip-on extensometer–specimen structure in tensile tests, MEASUREMENT, ISSN: 0263-2241, DOI: 10.1016/j.measurement.2014.11.035, Vol.63, pp.176-186, 2015
Tabin J., Prącik M., Methods for identifying dynamic parameters of clip-on extensometer–specimen structure in tensile tests, MEASUREMENT, ISSN: 0263-2241, DOI: 10.1016/j.measurement.2014.11.035, Vol.63, pp.176-186, 2015

Abstract:
This paper presents the dynamic analysis of clip-on extensometer–specimen structure subjected to uniaxial tensile tests. The dynamic behavior of such structure is influenced by vibrations that can be caused by external factors, such as vibrations carried by the tensile test machine, “cold-welding” effect (typically at ultra-low temperatures) or internal factors arising from the plastic instability of testing materials. The Portevin–Le Chatelier effect (PLC), discontinuous plastic flow phenomenon (DPF) or Lűders band propagation effect are the most prominent modes of plastic deformations, that are characterized by an oscillatory behavior (plastic instability). Both factors are included in our analysis.

Keywords:
Clip-on extensometer, Dynamic analysis, Tensile testing, Cryogenic temperatures

180.Skoczeń B., Bielski J., Tabin J., Multiaxial constitutive model of discontinuous plastic flow at cryogenic temperatures, International Journal of Plasticity, ISSN: 0749-6419, DOI: 10.1016/j.ijplas.2013.09.004, Vol.55, pp.198-218, 2014
Skoczeń B., Bielski J., Tabin J., Multiaxial constitutive model of discontinuous plastic flow at cryogenic temperatures, International Journal of Plasticity, ISSN: 0749-6419, DOI: 10.1016/j.ijplas.2013.09.004, Vol.55, pp.198-218, 2014

Abstract:
FCC metals and alloys are massively used in cryogenic applications down to the temperature of absolute zero, because of suitable physical and mechanical properties including high level ductility. Many of these materials undergo at low temperatures a process similar to dynamic strain ageing, reflected by the so-called discontinuous plastic flow (DPF, serrated yielding). The physically based multiaxial constitutive model presented in the paper constitutes a generalization of the previous uniaxial model that proved efficient in describing the plastic flow instabilities occurring at extremely low temperatures. The model takes into account thermodynamic background, including the phonon mechanism of heat transport and thermodynamic instability caused by specific heat vanishing with the temperature approaching absolute zero. The DPF is described by the mechanism of local catastrophic failure of lattice barriers (for instance Lomer-Cottrell locks) under the stress fields related to the accumulating edge dislocations. The failure of LC locks leads to massive motion of released dislocations accompanied by step-wise increase of the strain rate (macroscopic slip). In the present paper the plastic flow discontinuity associated with the proportional loading paths is studied. Identification of parameters of the constitutive model is based on the experimental data collected during several campaigns of tensile tests carried out on copper and stainless steel samples immersed in liquid helium (4.2 K).

Keywords:
Multiscale constitutive model, Discontinuous plastic flow, Cryogenic temperatures, Multiaxial loads

181.Azevedo Moreira R., de Melo C.P., On the separability of the extended molecule: Constructing the best localized molecular orbitals for an organic molecule bridging two model electrodes, JOURNAL OF CHEMICAL PHYSICS, ISSN: 0021-9606, DOI: 10.1063/1.4894845, Vol.141, pp.124712-1-10, 2014
Azevedo Moreira R., de Melo C.P., On the separability of the extended molecule: Constructing the best localized molecular orbitals for an organic molecule bridging two model electrodes, JOURNAL OF CHEMICAL PHYSICS, ISSN: 0021-9606, DOI: 10.1063/1.4894845, Vol.141, pp.124712-1-10, 2014

Abstract:
Based on a quantum chemical valence formalism that allows the rigorous construction of best-localized molecular orbitals on specific parts of an extended system, we examined the separability of individual components of model systems relevant to the description of electron transport in molecular devices. We started by examining how to construct the maximally localized electronic density at the tip of a realistic model of a gold electrode. By varying the number of gold atoms included in the local region where to project the total electronic density, we quantitatively assess how many molecular orbitals are entirely localized in that region. We then considered a 1,4-benzene-di-thiol molecule connected to two model gold electrodes and examined how to localize the electronic density of the total system in the extended molecule, a fractional entity comprising the organic molecule plus an increasing number of the closest metal atoms. We were able to identify in a rigorous manner the existence of three physically different electronic populations, each one corresponding to a distinct set of molecular orbitals. First, there are those entirely localized in the extended molecule, then there is a second group of those completely distributed in the gold atoms external to that region, and, finally, there are those delocalized over the entire system. This latter group can be associated to the shared electronic population between the extended molecule and the rest of the system. We suggest that the treatment here presented could be useful in the theoretical analysis of the electronic transport in nanodevices whenever the use of localized molecular states are required by the physics of the specific problem, such as in cases of weak coupling and super-exchange limits.

182.Petryk H., Fischer F.D., Marketz W., Clemens H., Appel F., An energy approach to the formation of twins in TiAl, METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, ISSN: 1073-5623, DOI: 10.1007/s11661-003-0184-z, Vol.34, No.12, pp.2827-2836, 2003
Petryk H., Fischer F.D., Marketz W., Clemens H., Appel F., An energy approach to the formation of twins in TiAl, METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, ISSN: 1073-5623, DOI: 10.1007/s11661-003-0184-z, Vol.34, No.12, pp.2827-2836, 2003

Abstract:
The energy criterion of stability of equilibrium is used to predict the formation of discrete twin bands running across the grains of polycrystalline solids. An uncontrolled rapid development of a twin band is assumed to occur when the associated release of elastic energy compensates the interfacial energy and intrinsic dissipation due to twinning. A simplified analysis is performed that leads to compact analytic formulae for the thickness of a twin band and for the critical resolved stress. The creation of subsequent discrete twin bands in a finite solid can be separated by the periods of quasistatic growth of existing twins under varying loads. An application of the energy criterion to twinning in TiAl intermetallics and its verification by observed data for the thickness of a twin band are presented.

183.Marjanović R., Szczepiński W., On the effect of biaxial cyclic loading on the yield surface of M-63 brass, ACTA MECHANICA, ISSN: 0001-5970, DOI: 10.1007/BF01177669, Vol.23, pp.65-74, 1975
Marjanović R., Szczepiński W., On the effect of biaxial cyclic loading on the yield surface of M-63 brass, ACTA MECHANICA, ISSN: 0001-5970, DOI: 10.1007/BF01177669, Vol.23, pp.65-74, 1975

Abstract:
Experimental results for thirtysix thin walled tubular specimens of M-63 brass are presented in a study of the effect of biaxial cyclic loading in the first and second quadrant of the principal stress plane on the shape of the yield surfaces. These results show that tested material strained cyclically beyond the initial yield locus works under a fully elastic regime after a few cycles of the initial transitory period.

184.Dietrich L., Szczepiński W., Plastic yielding of axially-symmetric bars with non-symmetric V-notch, ACTA MECHANICA, ISSN: 0001-5970, DOI: 10.1007/BF01178570, Vol.4, No.3, pp.230-240, 1967
Dietrich L., Szczepiński W., Plastic yielding of axially-symmetric bars with non-symmetric V-notch, ACTA MECHANICA, ISSN: 0001-5970, DOI: 10.1007/BF01178570, Vol.4, No.3, pp.230-240, 1967

Abstract:
The plastic incipient flow of V-notched axially symmetric bars with different slope of the two generators is considered using theTresca yield criterion and associated flow rule. The experimental results show good agreement with theoretical solutions.

Keywords:
Yield Criterion, Flow Rule