Publications reported by three months

1.Konowrocki R., Szolc T., An Analysis of Electromechanical Interactions in the Railway Vehicle Traction Drive Systems Driven by AC Motors, Proceedings of the International Scientific Conference Transport of the 21st Century,Research Methods and Solutions to Current Transport Problems. ISCT21 2019. Advances in Intelligent Systems and Computing, 2019-06-09/06-12, Ryn, Poland (PL), DOI: 10.1007/978-3-030-27687-4_23, Vol.1032, pp.236-245, 2020
Konowrocki R., Szolc T., An Analysis of Electromechanical Interactions in the Railway Vehicle Traction Drive Systems Driven by AC Motors, Proceedings of the International Scientific Conference Transport of the 21st Century,Research Methods and Solutions to Current Transport Problems. ISCT21 2019. Advances in Intelligent Systems and Computing, 2019-06-09/06-12, Ryn, Poland (PL), DOI: 10.1007/978-3-030-27687-4_23, Vol.1032, pp.236-245, 2020

Abstract:
In the paper dynamic electromechanical interactions between the rail-way drive systems and their driving electric motors are investigated. These are drive systems of high-speed trains (HST) and locomotives driven by AC motors. In particular, there is considered an influence of negative electromagnetic damp-ing generated by the asynchronous motor on a possibility of excitation of reso-nant torsional vibrations. The theoretical calculations have been performed by means of the advanced structural mechanical models. Conclusions drawn from the computational results can be very useful during a design phase of these ob-jects as well as helpful for their users during a regular maintenance

Keywords:
railway drive, electromechanical interactions, AC Motors, railway dynamic, numerical investigation

2.Kalinowski D., Konowrocki R., Szolc T., An influence of design features of tramway vehicles on kinematic extortion from geometry of a track, Proceedings of the International Scientific Conference Transport of the 21st Century,Research Methods and Solutions to Current Transport Problems. ISCT21 2019. Advances in Intelligent Systems and Computing, 2019-06-09/06-12, Ryn, Poland (PL), DOI: 10.1007/978-3-030-27687-4_21, Vol.1032, pp.204-214, 2020
Kalinowski D., Konowrocki R., Szolc T., An influence of design features of tramway vehicles on kinematic extortion from geometry of a track, Proceedings of the International Scientific Conference Transport of the 21st Century,Research Methods and Solutions to Current Transport Problems. ISCT21 2019. Advances in Intelligent Systems and Computing, 2019-06-09/06-12, Ryn, Poland (PL), DOI: 10.1007/978-3-030-27687-4_21, Vol.1032, pp.204-214, 2020

Abstract:
In the paper, simulation results of safety against derailment for a tramway vehicles with an arbitrary configuration of wagons and bogies is presented. The existing European standard EN 14363 covers all necessary tests for different railway vehicles, but it is inadequate for tramway vehicles, especially in safety against a derailment examination. Its operational conditions are much different. The described observations suggest that the methodology of safety against derailment testing described in the EN 14363 standard cannot be used without any modifications in the case of testing of tramway vehicles. On the basis of the computational results, a significant influence of different configurations of urban tramway vehicles on the wheel-rail contact forces was discussed, in particular on the Y/Q derailment factor

Keywords:
tramway dynamics, safety against derailment, simpack, numerical study

3.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, Vol.183, 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, Vol.183, 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

4.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

5.Frydrych K., Simulations of Grain Refinement in Various Steels Using the Three-Scale Crystal Plasticity Model, METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, ISSN: 1073-5623, DOI: 10.1007/s11661-019-05373-z, Vol.50, No.10, pp.4913-4919, 2019
Frydrych K., Simulations of Grain Refinement in Various Steels Using the Three-Scale Crystal Plasticity Model, METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, ISSN: 1073-5623, DOI: 10.1007/s11661-019-05373-z, Vol.50, No.10, pp.4913-4919, 2019

Abstract:
In this paper, the recently developed three-scale crystal plasticity model is applied to simulate microstructural evolution of austenitic and ferritic stainless steels subjected to large plastic strains. It is shown that the model is able to correctly predict both texture and misorientation angle distributions in the materials studied. Moreover, it can correctly capture the grain-refinement kinetics and the influence of the stacking fault energy. Finally, it is confirmed that the 3SCP model is a computationally attractive alternative for reliable modeling of microstructural evolutions in metals and alloys.

6.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

7.Maździarz M., Comment on ‘The Computational 2D Materials Database: high-throughput modeling and discovery of atomically thin crystals’, 2D Materials, ISSN: 2053-1583, DOI: 10.1088/2053-1583/ab2ef3, Vol.6, No.4, pp.048001-1-3, 2019
Maździarz M., Comment on ‘The Computational 2D Materials Database: high-throughput modeling and discovery of atomically thin crystals’, 2D Materials, ISSN: 2053-1583, DOI: 10.1088/2053-1583/ab2ef3, Vol.6, No.4, pp.048001-1-3, 2019

Abstract:
Recently Haastrup et al 2018 (2D Mater. 5 042002) introduced the Computational 2D Materials Database (C2DB), which organises a variety of structural, thermodynamic, elastic, electronic, magnetic, and optical properties of around 1500 two-dimensional materials distributed over more than 30 different crystal structures. Unfortunately, the work contains serious and fundamental flaws in the field of elasticity and mechanical stability tests that make it unreliable.

Keywords:
ab initio calculations; elastic stability; 2D materials; materials discovery

8.Kucharski S., Starzyński G., Contact of rough surfaces under normal and tangential loading, WEAR, ISSN: 0043-1648, DOI: 10.1016/j.wear.2019.203075, Vol.440-441, pp.203075-1-14, 2019
Kucharski S., Starzyński G., Contact of rough surfaces under normal and tangential loading, WEAR, ISSN: 0043-1648, DOI: 10.1016/j.wear.2019.203075, Vol.440-441, pp.203075-1-14, 2019

Abstract:
Contact between a deformable, random rough surface and a rigid flat counterpart was investigated experimentally and theoretically. In the experimental setup, two modes of rough surface flattening were performed, namely normal compression and sliding (tangential load) in presence of normal compression. The load-approach relationship and friction coefficient were measured. After unloading the surface, the topography was measured using scanning profilometry. The deformation of roughness zone, i.e. evolution of the real contact area (RCA), and roughness parameters were analysed. A model based on statistical analysis and a finite element solution was applied to predict the load–approach relationship. The numerical and experimental results were compared. The effect of friction coefficient was discussed.

Keywords:
Contact mechanics, Roughness, Normal load, Tangential load

9.Bobrowski A., Lipniacki T., Robin-type boundary conditions in transition from reaction-diffusion equations in 3D domains to equations in 2D domains, Journal of Differential Equations, ISSN: 0022-0396, DOI: 10.1016/j.jde.2019.08.022, Vol.268, No.1, pp.239-271, 2019
Bobrowski A., Lipniacki T., Robin-type boundary conditions in transition from reaction-diffusion equations in 3D domains to equations in 2D domains, Journal of Differential Equations, ISSN: 0022-0396, DOI: 10.1016/j.jde.2019.08.022, Vol.268, No.1, pp.239-271, 2019

Abstract:
We consider a singular limit of diffusion equations in 3D domains of thickness converging to zero. In the 2D limit the resulting reaction-diffusion equation has a source term resulting from the Robin-type boundary conditions imposed on boundaries of the original 3D domain. The proposed approach can be applied to constructing approximate solutions of diffusion problems in thin planar, cylindrical, or spherical layers between two membranes. As an example we refer to the problem of activation of B lymphocytes, which typically have large nuclei and a thin cytoplasmic layer which can be considered as a spherical shell. For this example, assuming additionally axial symmetry we provide a rigorous convergence theorem in the language of semigroups of operators.

Keywords:
Semigroups of operators, Degenerate convergence, Singular perturbation, Boundary conditions, Thin layers, Signaling pathways, Phosphorylation–dephosphorylation cycle

10.Ustrzycka A., Mróz Z., Kowalewski Z.L., Kucharski S., Analysis of fatigue crack initiation in cyclic microplasticity regime, INTERNATIONAL JOURNAL OF FATIGUE, ISSN: 0142-1123, DOI: 10.1016/j.ijfatigue.2019.105342, pp.1-15, 2019
Ustrzycka A., Mróz Z., Kowalewski Z.L., Kucharski S., Analysis of fatigue crack initiation in cyclic microplasticity regime, INTERNATIONAL JOURNAL OF FATIGUE, ISSN: 0142-1123, DOI: 10.1016/j.ijfatigue.2019.105342, pp.1-15, 2019

Abstract:
The present work provides description of fatigue crack initiation in metals subjected to cyclic loading within the nominal elastic or initial elastic-plastic regimes next passing to elastic response during cyclic deformation and shake down process. It is assumed that damage growth proceeds due to action of local stress, specified as the sum of mean stress and its fluctuations induced by material inhomogeneities such as grain boundaries, inclusions, cavities, boundary asperities, also due to design notches or holes introduced into the element. The damage growth model is proposed, based on the critical plane concept. The macrocrack initiation then corresponds to a critical value of accumulated damage. The modelling of damage growth is supported by Electronic Speckle Pattern Interferometry (ESPI) apparatus using the coherent laser light. The damage growth effect is analysed by microindentation tests. The fatigue tests are performed for high strength steel specimens with central hole.

Keywords:
Fatigue crack initiation, Micro-plasticity, Damage evolution, Optical ESPI method, Micro indentation

11.Bilmin K., Kujawska T., Grieb P., Sonodynamic Therapy for Gliomas. Perspectives and Prospects of Selective Sonosensitization of Glioma Cells, Cells, ISSN: 2073-4409, DOI: 10.3390/cells8111428, Vol.8, No.11, pp.1428-1-11, 2019
Bilmin K., Kujawska T., Grieb P., Sonodynamic Therapy for Gliomas. Perspectives and Prospects of Selective Sonosensitization of Glioma Cells, Cells, ISSN: 2073-4409, DOI: 10.3390/cells8111428, Vol.8, No.11, pp.1428-1-11, 2019

Abstract:
Malignant glial tumors (gliomas) are the second (after cerebral stroke) cause of death from diseases of the central nervous system. The current routine therapy, involving a combination of tumor resection, radio-, and chemo-therapy, only modestly improves survival. Sonodynamic therapy (SDT) has been broadly defined as a synergistic effect of sonication applied in combination with substances referred to as “sonosensitizers”. The current review focuses on the possibility of the use of tumor-seeking sonosensitizers, in particular 5-aminolevulinic acid, to control recurring gliomas. In this application, SDT employs a principle similar to that of the more widely-known photodynamic therapy of superficially located cancers, the difference being the use of ultrasound instead of light to deliver the energy necessary to eliminate the sensitized malignant cells. The ability of ultrasound to penetrate brain tissues makes it possible to reach deeply localized intracranial tumors such as gliomas. The major potential advantage of this variant of SDT is its relative non-invasiveness and possibility of repeated application. Until now, there have been no clinical data regarding the efficacy and safety of such treatment for malignant gliomas, but the preclinical data are encouraging.

Keywords:
glioma; ultrasound; sonodynamic therapy; ALA

12.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, pp.1-22, 2019
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, pp.1-22, 2019

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

13.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

14.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

15.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

16.Gruziel-Słomka M., Kondratiuk P., Szymczak P., Ekiel-Jeżewska M.L., Stokesian dynamics of sedimenting elastic rings, SOFT MATTER, ISSN: 1744-683X, DOI: 10.1039/c9sm00598f, Vol.15, pp.7262-7274, 2019
Gruziel-Słomka M., Kondratiuk P., Szymczak P., Ekiel-Jeżewska M.L., Stokesian dynamics of sedimenting elastic rings, SOFT MATTER, ISSN: 1744-683X, DOI: 10.1039/c9sm00598f, Vol.15, pp.7262-7274, 2019

Abstract:
We consider elastic microfilaments which form closed loops. We investigate how the loops change shape and orientation while settling under gravity in a viscous fluid. Loops are circular at the equilibrium. Their dynamics are investigated numerically based on the Stokes equations for the fluid motion and the bead–spring model of the microfilament. The Rotne–Prager approximation for the bead mobility is used. We demonstrate that the relevant dimensionless parameter is the ratio of the bending resistance of the filament to the gravitation force corrected for buoyancy. The inverse of this ratio, called the elasto-gravitation number [scr B, script letter B], is widely used in the literature for sedimenting elastic linear filaments. We assume that [scr B, script letter B] is of the order of 104–106, which corresponds to easily deformable loops. We find out that initially tilted circles evolve towards different sedimentation modes, depending on [scr B, script letter B]. Very stiff or stiff rings attain almost planar, oval shapes, which are vertical or tilted, respectively. More flexible loops deform significantly and converge towards one of several characteristic periodic motions. These sedimentation modes are also detected when starting from various shapes, and for different loop lengths. In general, multi-stability is observed: an elastic ring converges to one of several sedimentation modes, depending on the initial conditions. This effect is pronounced for very elastic loops. The surprising diversity of long-lasting periodic motions and shapes of elastic rings found in this work gives a new perspective for the dynamics of more complex deformable objects at micrometer and nanometer scales, sedimenting under gravity or rotating in a centrifuge, such as red blood cells, ring polymers or circular DNA.

17.Minafò G., Rezaee-Hajidehi M., Giambanco G., A Mechanical Approach for Evaluating the Distribution of Confinement Pressure in FRP-Wrapped Rectangular Columns, JOURNAL OF ENGINEERING MECHANICS-ASCE, ISSN: 0733-9399, DOI: 10.1061/(ASCE)EM.1943-7889.0001673, Vol.145, No.12, pp.04019092-1-9, 2019
Minafò G., Rezaee-Hajidehi M., Giambanco G., A Mechanical Approach for Evaluating the Distribution of Confinement Pressure in FRP-Wrapped Rectangular Columns, JOURNAL OF ENGINEERING MECHANICS-ASCE, ISSN: 0733-9399, DOI: 10.1061/(ASCE)EM.1943-7889.0001673, Vol.145, No.12, pp.04019092-1-9, 2019

Abstract:
In recent decades, fiber reinforced polymer (FRP) wrapping has become a common technique to retrofit reinforced concrete (RC) columns. Numerous research works have sought to verify analytically and experimentally its effectiveness in terms of enhancement of axial load bearing capacity and ductility. These studies highlighted that in the case of sharp-cornered sections, the maximum allowable confinement pressure is limited by premature failure at corners and, consequently, stress in the FRP, as well as the distribution of the confinement pressure, is not uniform. The prediction of this phenomenon is not straightforward, and existing theoretical studies propose complex numerical simulations, whereas technical codes provide simplified or empirical relationships for its assessment. This paper presents an analytical model for the evaluation of the effective distribution of confinement pressure in FRP confined concrete members with rounded corners. The model allows considering the interaction with the concrete core and different brittle failure modes, including FRP rupture and debonding. It leads to determining the distribution of the confinement pressure along the section. Results are compared with those achieved by finite-element (FE) analyses and with numerical and experimental data available in the literature. Good agreement is obtained in all cases, showing the reliability of the proposed model.

Keywords:
Fiber reinforced polymer (FRP) wrapping, Corner radius, Confinement pressure, Brittle failure

18.Nowak Ł.J., Nowak K.M., Perceptual audio processing stethoscope, JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, ISSN: 0001-4966, DOI: 10.1121/1.5126226, Vol.146, No.3, pp.1769-1773, 2019
Nowak Ł.J., Nowak K.M., Perceptual audio processing stethoscope, JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, ISSN: 0001-4966, DOI: 10.1121/1.5126226, Vol.146, No.3, pp.1769-1773, 2019

Abstract:
Stethoscopes are used to transmit body sounds related to various physiological processes to ears of a physician, providing basic or supportive information for eventual diagnosis. Unfavorably, the dominant frequency components of most of the auscultation signals are localized close to the lower frequency limits of the human auditory system, restricting the achievable selectivity and specificity. The present study introduces an approach that aims at overcoming the existing limitations. A signal processing scheme utilizing knock rejection, dynamic compressor, and pseudo-stereo synthesizer blocks is described, along with hardware implementation and results of the initial subjective evaluation.

19.Byra M., Wu M., Zhang X., Jang H., Ma Y-J., Chang E.Y., Shah S., Du J., Knee menisci segmentation and relaxometry of 3D ultrashort echo time cones MR imaging using attention U‐Net with transfer learning, Magnetic Resonance in Medicine, ISSN: 1522-2594, DOI: 10.1002/mrm.27969, Vol.83, No.3, pp.1-14, 2019
Byra M., Wu M., Zhang X., Jang H., Ma Y-J., Chang E.Y., Shah S., Du J., Knee menisci segmentation and relaxometry of 3D ultrashort echo time cones MR imaging using attention U‐Net with transfer learning, Magnetic Resonance in Medicine, ISSN: 1522-2594, DOI: 10.1002/mrm.27969, Vol.83, No.3, pp.1-14, 2019

Abstract:
Jiang Du, Department of Radiology, University of California, San Diego, CA 92103‐8226. Email: jiangdu@ucsd.edu Funding information The authors acknowledge grant support from GE Healthcare, NIH (1R01 AR062581, 1R01 AR068987 and 1R01 NS092650), and the VA Clinical Science Research & Development Service (1I01CX001388, I21RX002367). Purpose: To develop a deep learning‐based method for knee menisci segmentation in 3D ultrashort echo time (UTE) cones MR imaging, and to automatically determine MR relaxation times, namely the T1, T1ρ, and T∗ 2 parameters, which can be used to assess knee osteoarthritis (OA). Methods: Whole knee joint imaging was performed using 3D UTE cones sequences to collect data from 61 human subjects. Regions of interest (ROIs) were outlined by 2 experienced radiologists based on subtracted T1ρ‐weighted MR images. Transfer learning was applied to develop 2D attention U‐Net convolutional neural networks for the menisci segmentation based on each radiologist’s ROIs separately. Dice scores were calculated to assess segmentation performance. Next, the T1, T1ρ, T∗ 2 relaxations, and ROI areas were determined for the manual and automatic segmentations, then compared. Results: The models developed using ROIs provided by 2 radiologists achieved high Dice scores of 0.860 and 0.833, while the radiologists’ manual segmentations achieved a Dice score of 0.820. Linear correlation coefficients for the T1, T1ρ, and T∗ 2 relaxations calculated using the automatic and manual segmentations ranged between 0.90 and 0.97, and there were no associated differences between the estimated average meniscal relaxation parameters. The deep learning models achieved segmentation performance equivalent to the inter‐observer variability of 2 radiologists. Conclusion: The proposed deep learning‐based approach can be used to efficiently generate automatic segmentations and determine meniscal relaxations times. The method has the potential to help radiologists with the assessment of meniscal diseases, such as OA.

Keywords:
deep learning, menisci, osteoarthritis, quantitative MR, segmentation

20.Jeznach O., Kołbuk D., Sajkiewicz P., Aminolysis of Various Aliphatic Polyesters in a Form of Nanofibers and Films, Polymers, ISSN: 2073-4360, DOI: 10.3390/polym11101669, Vol.11, No.10, pp.1669-1-16, 2019
Jeznach O., Kołbuk D., Sajkiewicz P., Aminolysis of Various Aliphatic Polyesters in a Form of Nanofibers and Films, Polymers, ISSN: 2073-4360, DOI: 10.3390/polym11101669, Vol.11, No.10, pp.1669-1-16, 2019

Abstract:
Surface functionalization of polymer scaffolds is a method used to improve interactions of materials with cells. A frequently used method for polyesters is aminolysis reaction, which introduces free amine groups on the surface. In this study, nanofibrous scaffolds and films of three different polyesters–polycaprolactone (PCL), poly(lactide-co-caprolactone) (PLCL), and poly(l-lactide) (PLLA) were subjected to this type of surface modification under the same conditions. Efficiency of aminolysis was evaluated on the basis of ninhydrin tests and ATR–FTIR spectroscopy. Also, impact of this treatment on the mechanical properties, crystallinity, and wettability of polyesters was compared and discussed from the perspective of aminolysis efficiency. It was shown that aminolysis is less efficient in the case of nanofibers, particularly for PCL nanofibers. Our hypothesis based on the fundamentals of classical high speed spinning process is that the lower efficiency of aminolysis in the case of nanofibers is associated with the radial distribution of crystallinity of electrospun fiber with more crystalline skin, strongly inhibiting the reaction. Moreover, the water contact angle results demonstrate that the effect of free amino groups on wettability is very different depending on the type and the form of polymer. The results of this study can help to understand fundamentals of aminolysis-based surface modification.

Keywords:
aminolysis, polyester, electrospinning, nanofibers, film, surface chemical modification

21.Krajewski M., Liao P.Y., Michalska M., Tokarczyk M., Lin J.Y., Hybrid electrode composed of multiwall carbon nanotubes decorated with magnetite nanoparticles for aqueous supercapacitors, Journal of Energy Storage, ISSN: 2352-152X, DOI: 10.1016/j.est.2019.101020, Vol.26, pp.101020-101020, 2019
Krajewski M., Liao P.Y., Michalska M., Tokarczyk M., Lin J.Y., Hybrid electrode composed of multiwall carbon nanotubes decorated with magnetite nanoparticles for aqueous supercapacitors, Journal of Energy Storage, ISSN: 2352-152X, DOI: 10.1016/j.est.2019.101020, Vol.26, pp.101020-101020, 2019

Abstract:
This work describes a use of a composite nanomaterial which consists of multiwall carbon nanotubes covered by iron oxide nanoparticles as a hybrid electrode in aqueous supercapacitor. The investigated nanomaterial was manufactured in a two-step simple chemical synthesis in which the first step was a functionalization of carbon nanotubes whereas the second one was the deposition of iron oxide. According the morphological and structural characterization, the carbon nanotubes with diameters of 10–40 nm were successfully covered by randomlydispersed magnetite nanoparticles with average diameter of 10 nm. Moreover, the thermogravimetric analysis results indicated that the mass ratio between carbon nanotubes and iron oxide nanoparticles was about 65–35%. The electrochemical performance of studied hybrid electrode was tested in 1M aqueous KCl electrolyte. The highest specific capacitance of 143 F g‒1 was recorded at a discharge current density of 1 A g‒1. The investigated nanomaterial also exhibited excellent cycling stability i.e. 81% retention of the initial capacitance after 3000 cycles.

Keywords:
Hybrid electrode, Magnetite, Multiwall carbon nanotube, Nanocomposite, Supercapacitor

22.Cegielska O., Sajkiewicz P., Targeted Drug Delivery Systems for the Treatment of Glaucoma: Most Advanced Systems Review, Polymers, ISSN: 2073-4360, DOI: 10.3390/polym11111742, Vol.11, No.11, pp.1742-1-18, 2019
Cegielska O., Sajkiewicz P., Targeted Drug Delivery Systems for the Treatment of Glaucoma: Most Advanced Systems Review, Polymers, ISSN: 2073-4360, DOI: 10.3390/polym11111742, Vol.11, No.11, pp.1742-1-18, 2019

Abstract:
Each year, new glaucoma drug delivery systems are developed. Due to the chronic nature of the disease, it requires the inconvenient daily administration of medications. As a result of their elution from the eye surface and penetration to the bloodstream through undesired permeation routes, the bioavailability of active compounds is low, and systemic side effects occur. Despite numerous publications on glaucoma drug carriers of controlled drug release kinetics, only part of them consider drug permeation routes and, thus, carriers’ location, as an important factor affecting drug delivery. In this paper, we try to demonstrate the importance of the delivery proximal to glaucoma drug targets. The targeted delivery can significantly improve drug bioavailability, reduce side effects, and increase patients’ compliance compared to both commercial and scientifically developed formulations that can spread over the eye surface or stay in contact with conjunctival sac. We present a selection of glaucoma drug carriers intended to be placed on cornea or injected into the aqueous humor and that have been made by advanced materials using hi-tech forming methods, allowing for effective and convenient sustained antiglaucoma drug delivery.

Keywords:
hydrogels, nanofibers, electrospinning, glaucoma, ophthalmology

23.Niemczyk-Soczyńska B., Gradys A., Kołbuk D., Krzton-Maziopa A., Sajkiewicz P., Crosslinking Kinetics of Methylcellulose Aqueous Solution and Its Potential as a Scaffold for Tissue Engineering, Polymers, ISSN: 2073-4360, DOI: 10.3390/polym11111772, Vol.11, No.11, pp.1772-1-17, 2019
Niemczyk-Soczyńska B., Gradys A., Kołbuk D., Krzton-Maziopa A., Sajkiewicz P., Crosslinking Kinetics of Methylcellulose Aqueous Solution and Its Potential as a Scaffold for Tissue Engineering, Polymers, ISSN: 2073-4360, DOI: 10.3390/polym11111772, Vol.11, No.11, pp.1772-1-17, 2019

Abstract:
Thermosensitive, physically crosslinked injectable hydrogels are in the area of interests of various scientific fields. One of the representatives of this materials group is an aqueous solution of methylcellulose. At ambient conditions, methylcellulose (MC) is a sol while on heating up to 37 °C, MC undergoes physical crosslinking and transforms into a gel. Injectability at room temperature, and crosslinkability during subsequent heating to physiological temperature raises hopes, especially for tissue engineering applications. This research work aimed at studying crosslinking kinetics, thermal, viscoelastic, and biological properties of MC aqueous solution in a broad range of MC concentrations. It was evidenced by Differential Scanning Calorimetry (DSC) that crosslinking of MC is a reversible two-stage process, manifested by the appearance of two endothermic effects, related to the destruction of water cages around methoxy groups, followed by crosslinking via the formation of hydrophobic interactions between methoxy groups in the polymeric chains. The DSC results also allowed the determination of MC crosslinking kinetics. Complementary measurements of MC crosslinking kinetics performed by dynamic mechanical analysis (DMA) provided information on the final storage modulus, which was important from the perspective of tissue engineering applications. Cytotoxicity tests were performed using mouse fibroblasts and showed that MC at low concentration did not cause cytotoxicity. All these efforts allowed to assess MC hydrogel relevance for tissue engineering applications.

Keywords:
methylcellulose, thermosensitive hydrogel, crosslinking kinetics, DSC, DMA, cellular tests

24.Guo T., Ma Y-J., High R.A., Tang Q., Wong J.H., Byra M., Searleman A.C., To S.C., Wan L., Le N., Du J., Chang E., Assessment of an in vitro model of rotator cuff degeneration using quantitative magnetic resonance and ultrasound imaging with biochemical and histological correlation, European Journal of Radiology, ISSN: 0720-048X, DOI: 10.1016/j.ejrad.2019.108706, Vol.121, pp.108706-1-10, 2019
Guo T., Ma Y-J., High R.A., Tang Q., Wong J.H., Byra M., Searleman A.C., To S.C., Wan L., Le N., Du J., Chang E., Assessment of an in vitro model of rotator cuff degeneration using quantitative magnetic resonance and ultrasound imaging with biochemical and histological correlation, European Journal of Radiology, ISSN: 0720-048X, DOI: 10.1016/j.ejrad.2019.108706, Vol.121, pp.108706-1-10, 2019

Abstract:
Purpose Quantitative imaging methods could improve diagnosis of rotator cuff degeneration, but the capability of quantitative MR and US imaging parameters to detect alterations in collagen is unknown. The goal of this study was to assess quantitative MR and US imaging measures for detecting abnormalities in collagen using an in vitro model of tendinosis with biochemical and histological correlation. Method 36 pieces of supraspinatus tendons from 6 cadaveric donors were equally distributed into 3 groups (2 subjected to different concentrations of collagenase and a control group). Ultrashort echo time MR and US imaging measures were performed to assess changes at baseline and after 24 h of enzymatic digestion. Biochemical and histological measures, including brightfield, fluorescence, and polarized microscopy, were used to verify the validity of the model and were compared with quantitative imaging parameters. Correlations between the imaging parameters and biochemically measured digestion were analyzed. Results Among the imaging parameters, macromolecular fraction (MMF), adiabatic T1ρ, T2*, and backscatter coefficient (BSC) were useful in differentiating between the extent of degeneration among the 3 groups. MMF strongly correlated with collagen loss (r=-0.81; 95% confidence interval [CI]: -0.90,-0.66), while the adiabatic T1ρ (r = 0.66; CI: 0.42,0.81), T2* (r = 0.58; CI: 0.31,0.76), and BSC (r = 0.51; CI: 0.22,0.72) moderately correlated with collagen loss. Conclusions MMF, adiabatic T1ρ, and T2* measured and US BSC can detect alterations in collagen. Of the quantitative MR and US imaging measures evaluated, MMF showed the highest correlation with collagen loss and can be used to assess rotator cuff degeneration.

Keywords:
Rotator cuff tendon, Tendinopathy, Quantitative MRI, UTE, Quantitative ultrasound

25.Błoński S., Pręgowska A., Michalek T., Szczepański J., The use of Lempel-Ziv complexity to analyze turbulence and flow randomness based on velocity fluctuations, BULLETIN OF THE POLISH ACADEMY OF SCIENCES: TECHNICAL SCIENCES, ISSN: 0239-7528, DOI: 10.24425/bpasts.2019.130876, Vol.67, No.5, pp.957-962, 2019
Błoński S., Pręgowska A., Michalek T., Szczepański J., The use of Lempel-Ziv complexity to analyze turbulence and flow randomness based on velocity fluctuations, BULLETIN OF THE POLISH ACADEMY OF SCIENCES: TECHNICAL SCIENCES, ISSN: 0239-7528, DOI: 10.24425/bpasts.2019.130876, Vol.67, No.5, pp.957-962, 2019

Abstract:
One of the mathematical tools to measure the generation rate of new patterns along a sequence of symbols is the Lempel-Ziv complexity (LZ). Under additional assumptions, LZ is an estimator of entropy in the Shannon sense. Since entropy is considered as a measure of randomness, this means that LZ can be treated also as a randomness indicator. In this paper, we used LZ concept to the analysis of different flow regimes in cold flow combustor models. Experimental data for two combustor’s configurations motivated by efficient mixing need were considered. Extensive computer analysis was applied to develop a complexity approach to the analysis of velocity fluctuations recorded with hot-wire anemometry and PIV technique. A natural encoding method to address these velocity fluctuations was proposed. It turned out, that with this encoding the complexity values of the sequences are well correlated with the values obtained by means of RMS method (larger/smaller complexity larger/smaller RMS). However, our calculations pointed out the interesting result that most complex, this means most random, behavior does not overlap with the “most turbulent” point determined by the RMS method, but it is located in the point with maximal average velocity. It seems that complexity method can be particularly useful to analyze turbulent and unsteady flow regimes. Moreover, the complexity can also be used to establish other flow characteristics like its ergodicity or mixing.

Keywords:
turbulence, complexity, entropy, randomness

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.Ekiel-Jeżewska M.L., Bukowicki M., Sedimenting pairs of elastic microfilaments, SOFT MATTER, ISSN: 1744-683X, DOI: 10.1039/c9sm01373c, Vol.15, pp.9405-9417, 2019
Ekiel-Jeżewska M.L., Bukowicki M., 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.Roszkiewicz A., Jain A., Teodorczyk M., Nasalski W., Formation and Characterization of Hole Nanopattern on Photoresist Layer by Scanning Near-Field Optical Microscope, Nanomaterials, ISSN: 2079-4991, DOI: 10.3390/nano9101452, Vol.9, No.10, pp.1452-1-11, 2019
Roszkiewicz A., Jain A., Teodorczyk M., Nasalski W., Formation and Characterization of Hole Nanopattern on Photoresist Layer by Scanning Near-Field Optical Microscope, Nanomaterials, ISSN: 2079-4991, DOI: 10.3390/nano9101452, Vol.9, No.10, pp.1452-1-11, 2019

Abstract:
PatterningoflinesofholesonalayerofpositivephotoresistSXAR-P3500/6(AllresistGmbH, Strausberg, Germany) spin-coated on a quartz substrate is carried out by using scanning near-field optical lithography. A green 532 nm-wavelength laser, focused on a backside of a nanoprobe of 90 nm diameter, is used as a light source. As a result, after optimization of parameters like laser power, exposuretime,orsleeptime,itisconfirmedthatitispossibletoobtainauniformnanopattern structure in the photoresist layer. In addition, the lines of holes are characterized by a uniform depth (71–87nm)andrelativelyhighaspectratiorangingfrom0.22to0.26. Numericalmodellingperformed with a rigorous method shows that such a structure can be potentially used as a phase zone plate.

Keywords:
optical lithography; photoresist; quartz; hole nanopatterning

37.Oberbek P., Kozikowski P., Czarnecka K., Sobiech P., Jakubiak S., Jankowski T., Inhalation exposure to various nanoparticles in work environment—contextual information and results of measurements, Journal of Nanoparticle Research, ISSN: 1388-0764, DOI: 10.1007/s11051-019-4651-x, Vol.21, pp.222-1-24, 2019
Oberbek P., Kozikowski P., Czarnecka K., Sobiech P., Jakubiak S., Jankowski T., Inhalation exposure to various nanoparticles in work environment—contextual information and results of measurements, Journal of Nanoparticle Research, ISSN: 1388-0764, DOI: 10.1007/s11051-019-4651-x, Vol.21, pp.222-1-24, 2019

Abstract:
Outside the wide range of potential benefits, the use of nanomaterials can endanger human health, mostly through skin contact and the risk of inhalation. This article presents the results of harmonized measurements with contextual information on the emission of nanoparticles during the manufacturing and application of nanotechnology products. The purpose of the research was to investigate the actual levels of exposure to nano-objects in real working conditions in chosen Polish companies. Measurements were carried out in various workplaces: during silver nanoparticle synthesis, production of thin nanocarbon layers, 3D-printing with the use of a nanohydroxyapatite-polymer composite and the production of special seals from thin glass foils. Research was conducted on the basis of task-based measurements and offline microscopic analysis. Real-time particle DiSCmini counters were used to determine the nano-object concentration during different processes and events: samplers for collecting air dust, and a scanning electron microscope to confirm the presence of nanoparticles emitted from selected sources. Average particle sizes obtained with analysis of microscopic images were as follows: 46.7 ± 13.4 nm, 19.8 ± 4.8 nm, 22.4 ± 7.6 nm, 49.2 ± 26.3 nm respectively for workplaces. The concentration during significant events was referred to the background particle level. During one of the repeated processes, an unexpected and extremely high nanoparticle emission was recorded, which, in the long run, could cause a health hazard to workers. The studies have shown the importance of collective protective measures, revealed unexpected sources of accidentally generated nanoparticles and allowed to obtain knowledge about levels of exposure to nanoparticles during the various processes.

Keywords:
Nanoparticles, Ultrafine particles, Occupational exposure, Field monitoring, Occupational health, Real-time measurement

38.Lanzi M., Pierini F., Effect of Electron-Acceptor Content on the Efficiency of Regioregular Double-Cable Thiophene Copolymers in Single-Material Organic Solar Cells, ACS Omega, ISSN: 2470-1343, DOI: 10.1021/acsomega.9b02790, pp.A-L, 2019
Lanzi M., Pierini F., Effect of Electron-Acceptor Content on the Efficiency of Regioregular Double-Cable Thiophene Copolymers in Single-Material Organic Solar Cells, ACS Omega, ISSN: 2470-1343, DOI: 10.1021/acsomega.9b02790, pp.A-L, 2019

Abstract:
Three regioregular thiophenic copolymers, characterized by a bromine atom or a C60-fullerene group at different molar ratios at the end of a decamethylenic plastifying side chain, have been successfully synthesized using a straightforward postpolymerization functionalization procedure based on a Grignard coupling reaction. Owing to their good solubility in common organic solvents, the products were fully characterized using chromatographic, spectroscopic, thermal, and morphological techniques and used as single materials in the photoactive layers of organic solar cells. The photoconversion efficiencies obtained with copolymers were compared with those of a reference cell prepared using a physical blend of the precursor homopolymer and [6,6]-phenyl-C61-butyric acid methyl ester. The best results were obtained with COP2, the copolymer with a 21% molar content of C60-functionalized side chains. The use of the double-cable polymer made possible an enhanced control on the nanomorphology of the active blend, thus reducing phase-segregation phenomena as well as the macroscale separation between the electron-acceptor and -donor components, yielding a power conversion efficiency higher than that of the reference cell (4.05 vs 3.68%). Moreover, the presence of the halogen group was exploited for the photo-cross-linking of the active layer immediately after the thermal annealing procedure. The cross-linked samples showed an increased stability over time, leading to good efficiencies even after 120 h of accelerated aging: this was a key feature for the widespread practical applicability of the prepared devices.

39.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

40.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

41.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

42.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.

43.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

44.Sugak D., Syvorotka I., Yakhnevych U., Buryy O., Levintant-Zayonts N., Savytskyy H., Bonchyk O., Ubizskii S., Comparative Investigations of Nanohardness and Impurity Distribution Profiles of Lithium Niobate Single Crystals Diffusion Doped by Copper Ions, Crystal Research and Technology, ISSN: 1521-4079, DOI: 10.1002/crat.201900117, pp.1900117-1-7, 2019
Sugak D., Syvorotka I., Yakhnevych U., Buryy O., Levintant-Zayonts N., Savytskyy H., Bonchyk O., Ubizskii S., Comparative Investigations of Nanohardness and Impurity Distribution Profiles of Lithium Niobate Single Crystals Diffusion Doped by Copper Ions, Crystal Research and Technology, ISSN: 1521-4079, DOI: 10.1002/crat.201900117, pp.1900117-1-7, 2019

Abstract:
Spatial changes of optical and mechanical properties of doped lithium niobate (LN, LiNbO3) single crystals are investigated. The crystals are doped with copper ions by thermal diffusion at elevated temperatures. LiNbO3 crystal absorption spectra are recorded in a direction perpendicular to the direction of diffusion. The concentrations of copper ions are calculated using the Smakula–Dexter formula. To determine a relation between changes of optical and mechanical properties, the hardness profiles of the doped crystals are investigated by the nanoindentation technique. Young’s modulus and hardness are specified in accordance with the Oliver–Pharr method.

45.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.

46.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

47.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

48.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

49.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

50.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

51.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

52.Dobruch-Sobczak K., Piotrzkowska-Wróblewska H., Klimoda Z., Secomski W., Karwat P., Markiewicz-Grodzicka E., Kolasińska-Ćwikła A., Roszkowska-Purska K., Litniewski J., Monitoring the response to neoadjuvant chemotherapy in patients with breast cancer using ultrasound scattering coefficient: A preliminary report, Journal of Ultrasonography, ISSN: 2084-8404, DOI: 10.15557/JoU.2019.0013, Vol.19, No.77, pp.89-97, 2019
Dobruch-Sobczak K., Piotrzkowska-Wróblewska H., Klimoda Z., Secomski W., Karwat P., Markiewicz-Grodzicka E., Kolasińska-Ćwikła A., Roszkowska-Purska K., Litniewski J., Monitoring the response to neoadjuvant chemotherapy in patients with breast cancer using ultrasound scattering coefficient: A preliminary report, Journal of Ultrasonography, ISSN: 2084-8404, DOI: 10.15557/JoU.2019.0013, Vol.19, No.77, pp.89-97, 2019

Abstract:
Objective: Neoadjuvant chemotherapy was initially used in locally advanced breast cancer, and currently it is recommended for patients with Stage 3 and with early-stage disease with human epidermal growth factor receptors positive or triple-negative breast cancer. Ultrasound imaging in combination with a quantitative ultrasound method is a novel diagnostic approach. Aim of study: The aim of this study was to analyze the variability of the integrated backscatter coefficient, and to evaluate their use to predict the effectiveness of treatment and compare to ultrasound examination results. Material and method: Ten patients (mean age 52.9) with 13 breast tumors (mean dimension 41 mm) were selected for neoadjuvant chemotherapy. Ultrasound was performed before the treatment and one week after each course of neoadjuvant chemotherapy. The dimensions were assessed adopting the RECIST criteria. Tissue responses were classified as pathological response into the following categories: not responded to the treatment (G1, cell reduction by ≤9%) and responded to the treatment partially: G2, G3, G4, cell reduction by 10–29% (G2), 30–90% (G3), >90% (G4), respectively, and completely. Results: In B-mode examination partial response was observed in 9/13 cases (completely, G1, G3, G4), and stable disease was demonstrated in 3/13 cases (completely, G1, G4). Complete response was found in 1/13 cases. As for backscatter coefficient, 10/13 tumors (completely, and G2, G3, and G4) were characterized by an increased mean value of 153%. Three tumors 3/13 (G1) displayed a decreased mean value of 31%. Conclusion: The variability of backscatter coefficient, could be associated with alterations in the structure of the tumor tissue during neoadjuvant chemotherapy. There were unequivocal differences between responded and non-responded patients. The backscatter coefficient analysis correlated better with the results of histopathological verification than with the B-mode RECIST criteria.

Keywords:
integrated backscatter coefficient (IBSCs), neoadjuvant chemotherapy (NAC), breast cancer, ultrasound

53.Zaszczyńska A., Sajkiewicz P., Gradys A., Kołbuk D., Urbanek O., Cellular studies on piezoelectric polyvinylidene fluoride nanofibers subjected to ultrasounds stimulations, ENGINEERING OF BIOMATERIALS / INŻYNIERIA BIOMATERIAŁÓW, ISSN: 1429-7248, Vol.XXII, No.153, pp.25-25, 2019
54.Bajerski P., Pęcherski R., Chudy D., Jarecki L., Crystallization Kinetics of Polyamide 2200 in the Modelling of Additive Manufacturing Processes by FE Analyses, ENGINEERING TRANSACTIONS (ROZPRAWY INŻYNIERSKIE), ISSN: 0867-888X, DOI: 10.24423/EngTrans.1013.20190729, Vol.67, No.3, pp.301-309, 2019
Bajerski P., Pęcherski R., Chudy D., Jarecki L., Crystallization Kinetics of Polyamide 2200 in the Modelling of Additive Manufacturing Processes by FE Analyses, ENGINEERING TRANSACTIONS (ROZPRAWY INŻYNIERSKIE), ISSN: 0867-888X, DOI: 10.24423/EngTrans.1013.20190729, Vol.67, No.3, pp.301-309, 2019

Abstract:
The thermoplastic polymers present amorphous or semi-crystalline structures which are very important factors in describing volumetric shrinkage. The thermoplastic materials are commonly used for production of daily life products, industrial or as the prototypes. Different techniques of manufacturing polymer structures are considered like: injection molding, extrusion, milling, additive manufacturing (AM). AM is a very fast developing field in the manufacturing and research. Unfortunately, components or prototypes made using the thermoplastic semi-crystalline materials in 3D techniques have quite low mechanical strength compared to the parts made by injection molding processes. It is caused by porosity obtained during the processing, as well as by fraction of crystallinity in the volume of the components. Additionally, the volumetric shrinkage is hard to predict without knowledge of its origin. Therefore, it is necessary to consider crystallization kinetics and the melting of the analysed materials. The investigations presented in this work concern the crystallization and melting model to be implemented in the finite element (FE) analyses. With use of the model, one can predict development of the structure during the real processes and, in the future, to control the warpage of the manufactured components.

Keywords:
additive manufacturing; Avrami model; crystallization; Differential Scanning Calorimetry (DSC); glass transition temperature; Hoffman-Lauritzen theory; melting; PA2200; van Krevelen empirical model.

55.Kovalchuk V., Gołubowska B., Mladenov I.M., Mechanics of infinitesimal test bodies on Delaunay surfaces: spheres and cylinders as limits of unduloids and their action-angle analysis, Journal of Geometry and Symmetry in Physics, ISSN: 1312-5192, DOI: 10.7546/jgsp-53-2019-55-84, Vol.53, pp.55-84, 2019
Kovalchuk V., Gołubowska B., Mladenov I.M., Mechanics of infinitesimal test bodies on Delaunay surfaces: spheres and cylinders as limits of unduloids and their action-angle analysis, Journal of Geometry and Symmetry in Physics, ISSN: 1312-5192, DOI: 10.7546/jgsp-53-2019-55-84, Vol.53, pp.55-84, 2019

Abstract:
This paper discusses the motion of infinitesimal gyroscopes along the two-dimensional surfaces of constant mean curvature embedded into the three-dimensional Euclidean space. We have considered the cases of unduloids, spheres, and cylinders for which the corresponding Hamilton-Jacobi equations are written and analyzed with the help of the action-angle variables. Spheres and cylinders are considered as limiting cases of unduloids and the residue analysis was performed which provides the connection between all three action variables and the energy. This has been traced also for the geodetic situations and for two additional classical model potentials.

Keywords:
action-angle variables, affinely-rigid bodies, d'Alembert mechanics, Delaunay surfaces, geometry of curves and surfaces, Hamilton-Jacobi equation, harmonic/anharmonic oscillator potential models, infinitesimal test bodies, residue analysis, Riemannian spaces.

56.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
57.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

58.Rustighi E., Jankowski Ł., Prediction of acoustic emission of a rigid electrodes DEAP loudspeaker, RASD, 13th International Conference on Recent Advances in Structural Dynamics, 2019-04-15/04-17, Lyon, France (FR), pp.1-4, 2019
Rustighi E., Jankowski Ł., Prediction of acoustic emission of a rigid electrodes DEAP loudspeaker, RASD, 13th International Conference on Recent Advances in Structural Dynamics, 2019-04-15/04-17, Lyon, France (FR), pp.1-4, 2019

Abstract:
Dielectric Electro-Active Polymers (DEAPs) are lightweight 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, at DEAP loudspeakers have been prototyped and tested but no numerical prediction of their acoustic perfomances has been presented. In this paper an elemental model is presented, where the electrodes are modelled as bending plates, the dielectric as a Winkler bedding and the acoustic impedance calculated assuming baffled conditions. The impedances of the elements are stacked together and preliminary results are shown.

59.Błachowski B., Tauzowski P., Świercz A., Jankowski Ł., Sensor placement for structural damage identification by means of topology optimization, 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
Błachowski B., Tauzowski P., Świercz A., Jankowski Ł., Sensor placement for structural damage identification by means of topology optimization, 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

Abstract:
Damage identification attracted a lot of attention during the last three decades. The reason for that is the fact that large number of existing civil infrastructures reached their service life and growing number of structures is equipped with Structural Health Monitoring (SHM) systems. A successful structural damage identification is determined by three inseparably coupled factors: sensor placement, damage location and its extend, and finally location and time-frequency characteristics of the applied excitation. The purpose of this study is to address the first of the mentioned aspects, namely optimal sensor placement. A vast literature has been devoted to optimal sensor placement methods among which Effective Independence (EI) method proposed by Kammer and Tinker is one of the most successfully applied in practice. However, EI method is dedicated rather to test-analysis correlation and therefore more specific methods for damage identification are still needed. Additionally, in the case of large civil structures, which are intended to be equipped with large amount of sensors of different type, other sensor placement methods can be more efficient. Recently, a promising idea of utilizing a topology optimization approach for the purpose of sensor placement has been proposed by Bruggi and Mariani. The goal of this study is to extend their method, which has been verified on a plate structure, to the case of a FE model of a real arch bridge structure consisting a few thousands degrees of freedom. The main purpose of this work is to find the optimal arrangement of sensors on the structure to detect defects most accurately. The objective function for the problem formulated in this way is the total, weighted difference between the deformation of a damaged and undamaged state. This problem is very similar to the topological optimization, where we search for the optimal material distribution minimizing the mass of the structure while meeting the conditions related to some mechanical properties such as the maximum displacement of the structure, stress intensity or load capacity. This similarity led us to apply topological optimization to the problem of optimal placement of damage sensors. Several numerical examples prove the applicability of topological optimization for optimal sensor placement problem.

Keywords:
Sensor Placement, Damage Identification, Topology Optimization

60.Piechocka I.K., Wolska N., Luzak B., The role of shear flow in glycosylated fibrin clot response, 3rd Interdisciplinary FNP Conference, 2019-04-11/04-12, Warszawa (PL), pp.39, 2019
61.Piechocka I.K., Wolska N., Luzak B., Glycation of fibrinogen affects FXIII-induced crosslinking and shear flow response of fibrin networks, The 44th FEBS Congress, 2019-07-06/07-11, Kraków (PL), pp.132, 2019
62.Piechocka I.K., Wolska N., Luzak B., Shear flow promotes isotropic redistribution of fibrin fibers inside glycosylated fibrin networks, Joint 12th EBSA congress and 10th ICBT-IUPAP congress, 2019-07-20/07-24, Madryt (ES), pp.100, 2019
63.Liou S.C., Krajewski M., Chiou W.A., Tokarczyk M., Kowalski G., TEM Studies of Fe1-xNix Nanowires by Magnetic-Field-Induced Synthesis, M&M 2019, Microscopy & Microanalysis 2019, 2019-08-04/08-08, Portland (US), DOI: 10.1017/S143192761901170X, No.25, pp.2194-2195, 2019
64.Krajewski M., Tokarczyk M., Witecka A., Lewińska S., Ślawska-Waniewska A., Liou S.C., Chiou W.A., Płocińska M., Towards magnetic 1D nanostructures - magnetic field as a growth parameter, LIV Zakopane School of Physics Breaking Frontiers: Submicron Structures in Physics and Biology, 2019-05-21/05-25, Zakopane (PL), pp.42-42, 2019
65.Krajewski M., Tokarczyk M., Witecka A., Lewińska S., Ślawska-Waniewska A., Małolepszy A., Liou S.C., Chiou W.A., Manufacturing and magnetic properties of FexCo1‒x wire-like nanoalloys, CNM 2019, 6th CONFERENCE ON NANO- AND MICROMECHANICS, 2019-07-03/07-05, Rzeszów (PL), pp.103-104, 2019
Krajewski M., Tokarczyk M., Witecka A., Lewińska S., Ślawska-Waniewska A., Małolepszy A., Liou S.C., Chiou W.A., Manufacturing and magnetic properties of FexCo1‒x wire-like nanoalloys, CNM 2019, 6th CONFERENCE ON NANO- AND MICROMECHANICS, 2019-07-03/07-05, Rzeszów (PL), pp.103-104, 2019

Keywords:
magnetic-field-induced process, magnetic material, nanoalloy, wire-like nanostructure

66.Krajewski M., Magnetic-field-assisted synthesis of iron-based wire-like nanostructures, IMSNC-2019, 2nd International Conference on Material Science and Nanotechnology, 2019-07-15/07-17, London (GB), pp.48-48, 2019
67.Krajewski M., Tokarczyk M., Stefaniuk T., Kowalski G., Lewińska S., Ślawska-Waniewska A., High temperature treatment of nanochains composed of Fe1‒xCox nanoparticles, IBCM 2019, III International Baltic Conference on Magnetism: focus on nanobiomedicine and smart materials, 2019-08-18/08-22, Svetlogorsk (RU), pp.52-52, 2019
68.Kalociński D., Steifer T., An Almost Perfectly Predictable Process with No Optimal Predictor, IEEE-ISIT, IEEE International Symposium on Information Theory, 2019-07-07/07-12, Paryż (FR), DOI: 10.1109/ISIT.2019.8849587, pp.2504-2508, 2019
Kalociński D., Steifer T., An Almost Perfectly Predictable Process with No Optimal Predictor, IEEE-ISIT, IEEE International Symposium on Information Theory, 2019-07-07/07-12, Paryż (FR), DOI: 10.1109/ISIT.2019.8849587, pp.2504-2508, 2019

Abstract:
A novel kind of a negative result is presented for the problem of computable prediction. A non-stationary binary stochastic process is constructed for which almost surely no effective method of prediction achieves the infimum of prediction errors defined as the normalized Hamming distance between the sequence of predictions and the realization of the process. Yet it is shown that this process may be effectively predicted almost surely up to an arbitrarily small error since the infimum of prediction errors is zero.

69.Byra M., Sznajder T., Korzinek D., Piotrzkowska-Wróblewska H., Dobruch-Sobczak K., Nowicki A., Marasek K., Impact of Ultrasound Image Reconstruction Method on Breast Lesion Classification with Deep Learning. Pattern Recognition and Image Analysis, IbPRIA 2019, 9th Iberian Conference on Pattern Recognition and Image Analysi, 2019-07-01/07-04, Madryt (ES), pp.41-52, 2019
Byra M., Sznajder T., Korzinek D., Piotrzkowska-Wróblewska H., Dobruch-Sobczak K., Nowicki A., Marasek K., Impact of Ultrasound Image Reconstruction Method on Breast Lesion Classification with Deep Learning. Pattern Recognition and Image Analysis, IbPRIA 2019, 9th Iberian Conference on Pattern Recognition and Image Analysi, 2019-07-01/07-04, Madryt (ES), pp.41-52, 2019

Abstract:
In this work we investigate the usefulness and robustness of transfer learning with deep convolutional neural networks (CNNs) for breast lesion classification in ultrasound (US). Deep learning models can be vulnerable to adversarial examples, engineered input image pixel intensities perturbations that force models to make classification errors. In US imaging, distribution of US image pixel intensities relies on applied US image reconstruction algorithm. We explore the possibility of fooling deep learning models for breast mass classification by modifying US image reconstruction method. Raw radio-frequency US signals acquired from malignant and benign breast masses were used to reconstruct US images, and develop classifiers using transfer learning with the VGG19, InceptionV3 and InceptionResNetV2 CNNs. The areas under the receiver operating characteristic curve (AUCs) obtained for each deep learning model developed and evaluated using US images reconstructed in the same way were equal to approximately 0.85, and there were no associated differences in AUC values between the models (DeLong test p-values > 0.15). However, due to small modifications of the US image reconstruction method the AUC values for the models utilizing the VGG19, InceptionV3 and InceptionResNetV2 CNNs significantly decreased to 0.592, 0.584 and 0.687, respectively. Our study shows that the modification of US image reconstruction algorithm can have significant negative impact on classification performance of deep models. Taking into account medical image reconstruction algorithms may help develop more robust deep learning computer aided diagnosis systems.

Keywords:
Adversarial attacks, Breast lesion classification, Computer aided diagnosis, Deep learning, Robustness, Ultrasound imaging, Transfer learning

70.Nowicki A., Bezpieczeństwo badań ultrasonograficznych – wskaźniki termiczny i mechaniczny, Inżynier i Fizyk Medyczny, ISSN: 2300-1410, Vol.8, No.4, pp.325-330, 2019
Nowicki A., Bezpieczeństwo badań ultrasonograficznych – wskaźniki termiczny i mechaniczny, Inżynier i Fizyk Medyczny, ISSN: 2300-1410, Vol.8, No.4, pp.325-330, 2019

Abstract:
W ciągu ostatnich kilku dziesięcioleci ultradźwięki znalazły szerokie zastosowanie w diagnostyce obrazowej. Ten artykuł przeglądowy omawia potencjalne efekty biologiczne związane z propagacją ultradźwięków w tkankach i podaje fizyczne podstawy wprowadzonych indeksów mechanicznego MI i ter micznego TI zgodnych z Output Display Standard (ODS). W praktyce klinicznej otrzymywane wyniki są kompromisem pomiędzy jakością obrazu a możliwością systemu uzyskiwania zadowalających obrazów głęboko leżących struktur tkankowych – wyboru dokonuje się, biorąc pod uwagę minimalizację bioefektów. Moce wyjściowe ultrasonografów są regulowane i ograniczane do określonych poziomów. Bezpieczne dawki ultradźwiękowe wyznacza się według określonych zasad, a na ekranie wyświetlane są związane z nimi wielkości. Wielkości te określają możliwości wystąpienia zmian mechanicznych i termicznych w tkankach i dlatego mają znaczenia kliniczne. Wprowadzone wskaźniki – mechaniczny MI i termiczny TI uwzględniają fizyczny mechanizm oddziaływania między ultradźwiękami i biologiczną tkanką, który zależy od czasowych i przestrzennych parametrów pola akustycznego generowanego przez głowice ultradźwiękowe. Przewidywany wzrost temperatury określa się, stosując trzy różne modele tkankowe: homogeniczny, warstwowy i układ kość/tkanka

Keywords:
ultrasonografia, wskaźnik termiczny TI, wskaźnik mechaniczny MI, kawitacja, standardy IEC

71.Mościcki T., Psiuk R., Słomińska H., Influence of titanium addition on the phase composition and properties of tungsten borides thin films, PLATHINIUM, Plasma Thin film International Union Meeting, 2019-09-23/09-27, Antibes (FR), pp.1-2, 2019
72.Szmidt T., Konowrocki R., Pisarski D., Stabilization of a cantilever pipe conveying fluid using electromagnetic actuators of the transformer type, 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
Szmidt T., Konowrocki R., Pisarski D., Stabilization of a cantilever pipe conveying fluid using electromagnetic actuators of the transformer type, 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

Keywords:
Pipe Conveying Fluid, Electromagnetic Actuator, Stability, Flutter Experiment

73.Mackiewicz S., Modelowanie propagacji fal ultradźwiękowych w badaniach nieniszczących, XXV Seminarium Nieniszczące Badania Materiałów, 2019-03-20/03-22, Zakopane (PL), pp.111-130, 2019
74.Mackiewicz S., Badania eksploatacyjne korozji rurociągów technikami radiografii cyfrowej, KKBR Stary Młyn, KRAJOWA KONFERENCJA BADAŃ RADIOGRAFICZNYCH STARY MŁYN, 2019-09-09/09-11, Bolesławiec k/Wieruszowa (PL), pp.7-23, 2019
75.Pieczyska E., Kowalewski Z., Dunic V., Slavkovic R., Matsui R., Investigation of mechanical and thermomechanical effects in shape memory alloy during transformationinduced creep phenomena, DAS 2019, 36th DANUBIA-ADRIA Symposium on Advances in Experimental Mechanics, 2019-09-24/09-27, Pilzno (CZ), pp.91-92, 2019
76.Glinicki M.A., Problem reaktywności kruszywa – cz. 1 rozpoznanie, Budownictwo, Technologie, Architektura, ISSN: 1644-745X, Vol.1, pp.58-60, 2019
Glinicki M.A., Problem reaktywności kruszywa – cz. 1 rozpoznanie, Budownictwo, Technologie, Architektura, ISSN: 1644-745X, Vol.1, pp.58-60, 2019

Abstract:
Przemysł cementowy uznaje, że problem reaktywności to problem jakości kruszywa. Producenci kruszyw mineralnych uważają, że reaktywność jest problemem jakości cementu. A Komisja Europejska uważa, że najważniejszy jest wolny handel. Tak w skrócie można scharakteryzować stan normalizacji betonu i jego składników według Europejskiego Komitetu Normalizacyjnego CEN w zakresie bardzo istotnym dla zarządców i użytkowników obiektów betonowych, zwłaszcza nawierzchni kluczowych autostrad i mostów, projektowanych co najmniej na 50-100 lat użytkowania.

77.Glinicki M.A., Problem reaktywności kruszywa – cz. 2 kategoryzacja i przeciwdziałanie, Budownictwo, Technologie, Architektura, ISSN: 1644-745X, Vol.3, pp.62-65, 2019
78.Glinicki M.A., Właściwości betonu nawierzchniowego z kruszywem odkrytym – wpływ rodzaju cementu i pielęgnacji, DROGOWNICTWO, ISSN: 0012-6357, Vol.4, pp.99-104, 2019
Glinicki M.A., Właściwości betonu nawierzchniowego z kruszywem odkrytym – wpływ rodzaju cementu i pielęgnacji, DROGOWNICTWO, ISSN: 0012-6357, Vol.4, pp.99-104, 2019

Abstract:
Przestawiono analizę zagadnień projektowania składu betonu nawierzchniowego z kruszywem odkrytym, przeznaczonego na nawierzchnie drogowe o kategorii ruchu KR5-KR7. Omówiono wyniki badań betonu wykonanego w laboratorium w sposób imitujący wykonanie warstwy z kruszywem odkrytym. Wyznaczono wytrzymałość betonu, charakterystykę porów, szybkość absorpcji powierzchniowej wody i mrozoodporność powierzchniową w obecności roztworu chlorku sodu. Wyniki badań przeanalizowano w odniesieniu do zróżnicowania rodzaju cementu (CEM I, CEM III/A) i rodzaju pielęgnacji. Stwierdzono znaczący wzrost złuszczeń powierzchniowych i szybkości penetracji wody skorelowany z niedostatkiem pielęgnacji.

Keywords:
beton napowietrzony, charakterystyka porów, mrozoodporność, nawierzchnia drogowa dwuwarstwowa, pielęgnacja, przepuszczalność, warstwa z kruszywem odkrytym

79.Pieczyska E.A., Golasiński K., Maj M., Staszczak M., Furuta T., Kuramoto S., Gum metal subjected to tension at various strain rates - experimental results analysed by dic, 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
Pieczyska E.A., Golasiński K., Maj M., Staszczak M., Furuta T., Kuramoto S., Gum metal subjected to tension at various strain rates - experimental results analysed by dic, 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

Keywords:
Gum metal, Titanium alloy, Tensile loading, Digital Image Correlation

80.Golasiński K., Pieczyska E.A., Maj M., Staszczak M., Takesue N., Thermomechanical behavior of gum metal under cyclic compression, 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
Golasiński K., Pieczyska E.A., Maj M., Staszczak M., Takesue N., Thermomechanical behavior of gum metal under cyclic compression, 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

Keywords:
Gum Metal, Multifunctional Ti-based Alloy, Cyclic Compression, Infrared Thermography

81.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, AITA 2019, 15th International Workshop on Advanced Infrared Technology and Applications, 2019-09-16/09-19, Florencja (IT), pp.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, AITA 2019, 15th International Workshop on Advanced Infrared Technology and Applications, 2019-09-16/09-19, Florencja (IT), pp.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 alpha" nanodomains.

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

82.Dulnik J., Sajkiewicz P., Characterization of bicomponent polycaprolactone/gelatin electrospun nanofibres crosslinked with edc/nhs, 28th Annual Conference of the Polish Society for Biomaterials 'Biomaterials in Medicine and Veterinary Medicine, 2019-10-10/10-13, Rytro (PL), pp.26-26, 2019
83.Zaszczyńska A., Sajkiewicz P., Gradys A., Kołbuk D., Urbanek O., Cellular studies of piezoelectric nanofibers with ultrasound stimulations, Aerogels Processing, Modelling and Environmental-Driven Applications, 2019-10-21/10-23, Coimbra (PT), No.P04, pp.36, 2019
84.Sajkiewicz P., Jeznach O., Kołbuk-Konieczny D., Functionalization of Aliphatic Polyester Fibers Formed by Electrospinning - The Effect of Crystallinity on Aminolysis, BIOMATSEN, 4th International Congress on Biomaterials and Biosensors, 2019-05-12/05-18, Fethiye (TR), No.Id-289, pp.96-97, 2019
Sajkiewicz P., Jeznach O., Kołbuk-Konieczny D., Functionalization of Aliphatic Polyester Fibers Formed by Electrospinning - The Effect of Crystallinity on Aminolysis, BIOMATSEN, 4th International Congress on Biomaterials and Biosensors, 2019-05-12/05-18, Fethiye (TR), No.Id-289, pp.96-97, 2019

Keywords:
Nanofibers, polyesters, surface functionalization, aminolysis, structure

85.Psiuk R., Garbiec D., Wiśniewska M., Denis P., Mościcki T., Mikrostruktura i właściwości borków wolframu domieszkowanych cyrkonem wytwarzanych metodą spiekania iskrowo-plazmowego SPS, OSSPS, II Ogólnopolskie Seminarium Spark Plasma Sintering, 2019-10-24/10-24, Warszawa (PL), pp.20-20, 2019
86.Jurczak G., Dłużewski P., The effect of finite strain measure change on second-order piezoelectricity, EUROMAT 2019, European Congress and Exhibition on Advanced Materials and Processes 2019, 2019-09-01/09-05, Stockholm (SE), pp.1, 2019
Jurczak G., Dłużewski P., The effect of finite strain measure change on second-order piezoelectricity, EUROMAT 2019, European Congress and Exhibition on Advanced Materials and Processes 2019, 2019-09-01/09-05, Stockholm (SE), pp.1, 2019

Abstract:
Very rapid technological development in the electronic branch of the industry observed during last decades, together with the progressive miniaturisation of electronic devices induce increasing interest in the subject of piezoelectric semiconducting heterostructures. In some cases, the linearity of the piezoelectric effect under extreme strain and electric field conditions is challenged for these heterostructures. There are many experimental reports in the literature dealing with nonlinear piezoelectricity as well as theoretical calculations which predict the nonlinear behaviour of such crystalline heterostructures.

If, as stated above, the nonlinearity appears under extreme load conditions, therefore from the point of view of mechanics a finite deformation approach shoud be applied to properly describe the kinematics of the deformed crystal. Thus, problem of the choice of a proper strain measure appears as far as many different finite strain measures can be used to describe deformation of the body. Furthermore, higher order piezoelectric coefficients which are derivatives of the heterostructure energy (deformation in the vicinity of the natural state of the body) over the strain depends on the choice of the strain measure [1,2].

Theoretical prediction shows that second-order piezoelectric coefficients are finite strain measure dependent. Therefore, the use of any finite strain measure in constitutive modelling of nonlinear piezoelectric materials requires an adequate choice of higher-order piezoelectric coefficients. Otherwise, erroneous elastic and electric fields may appear in the case of modelling of nonlinear piezoelectric phenomena, e.g. for quantum heterostructures such as wells or dots. A further implication of that effect is that a complete set of second-order piezoelectric coefficients should contain additional information about
the strain measure applied during calculations or measurements.

General transformation formula for second-order piezoelectric coefficients (elastostriction) is derived as well as individual transformation formulae for common crystallographic classes (e.g. cubic, hexagonal).

References:
1. Dłużewski, P. (2000). J. Elast. 60, 119–129.
2. Jurczak, G. (2018) Acta Cryst. A74, 518–523.

Keywords:
piezoelectricity; second order piezoelectric coefficients;

87.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
88.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

89.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

90.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,

91.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
92.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

93.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

94.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.

95.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

96.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

97.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

98.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.

99.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
100.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
101.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
102.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
103.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, 2019
104.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

105.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
106.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

107.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

108.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.

109.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

110.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

111.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
112.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
113.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
114.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

115.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

116.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.

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

118.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
119.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
120.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

121.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
122.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.

123.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

124.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
125.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
126.Libura T., Kowalewski Z., 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
127.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
128.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

129.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
130.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
131.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
132.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
133.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.

134.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

135.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

136.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

137.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

138.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.

139.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.

140.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].

141.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
142.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
143.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
144.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
145.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
146.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.

147.Ekiel-Jeżewska M., Tradycje i nowoczesność, Gazeta Samorządowa MIM, ISSN: 1507-4447, Vol.4/276, pp.16-17, 2019
148.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, IEEE IUS, IEEE International Ultrasonics Symposium, 2019-10-06/10-09, Glasgow (Szkocja) (GB), pp.1-3, 2019
149.Karwat P., Klimonda Z., Piotrzkowska-Wróblewska H., Dobruch-Sobczak K., Litniewski J., Quantitative ultrasound examination of peritumoral tissue improves classification of breast lesions, IEEE IUS, IEEE International Ultrasonics Symposium, 2019-10-06/10-09, Glasgow (Szkocja) (GB), pp.1-3, 2019
150.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

151.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

152.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

153.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.

154.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
155.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
156.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
157.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.

158.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), No.1, 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), No.1, 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

159.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
160.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
161.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
162.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
163.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

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

165.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: https://doi.org/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: https://doi.org/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

166.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, Danmark (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, Danmark (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

167.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.

168.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

169.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
170.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
171.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: https://doi.org/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: https://doi.org/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

172.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
173.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
174.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

175.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

176.Ignaczak J., Stress-heat flux characterization of linear dynamic coupled thermoelasticity for an inhomogeneous isotropic infinite cylinder under plane strain conditions and zero heat flux normal to the plane, COMPOSITE INTERFACES, ISSN: 0927-6440, DOI: 10.1080/01495739.2018.1492358, Vol.41, pp.1201-1211, 2018
Ignaczak J., Stress-heat flux characterization of linear dynamic coupled thermoelasticity for an inhomogeneous isotropic infinite cylinder under plane strain conditions and zero heat flux normal to the plane, COMPOSITE INTERFACES, ISSN: 0927-6440, DOI: 10.1080/01495739.2018.1492358, Vol.41, pp.1201-1211, 2018

Abstract:
Stress-heat flux characterization of linear dynamic coupled thermoelasticityfor an inhomogeneous isotropic infinite cylinder under plane strain conditions and zero heat-flux normal to the plane is presented. It is shown that for a bounded cross-section of the cylinder, a 3D stress-heat flux process is generated by a 2D one, and a uniqueness theorem for the associated 2D initial-boundary value problem is established. In addition, an asymptotic approach to the 2D stress-heat flux initial-boundary value problem, in the form of a power series with respect to a small thermoelastic coupling field, is proposed. Also, Green' s formulas for time-periodic complex-valued solutions to 2D stress-heat flux field equations are obtained; and the existence of a globally constrained real-valued periodic and attenuated on the timeaxis stress-heat flux mode satisfying homogeneous natural boundary conditions is proved. The stress-heat flux characterization covers a large class of FGM's with physical properties smoothly distributed over the cross-section of the infinite cylinder. The results obtained are complementary to those of linear dynamic coupled thermoelasticity published up to date and should prove useful for a number of researchers in the field.

Keywords:
Existence of a stress-heat flux mode, Green's formulas, isotropic inhomogeneous media, linear dynamic coupled thermoelasticity, stressheat flux characterization, stress-heat flux field equations of linear thermo-elastodynamics, uniqueness theorem

177.Szymczak T., Brodecki A., Kowalewski Z., 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., 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

178.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

179.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

180.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

181.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

182.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

183.Lewis R.W., Postek E.W., Gethin D.T., Yang X.S., Pao W.K.S., Chao L., Numerical methods in simulation of industrial processes, AET2006, First International Conference on Advances in Engineering and Technology, 2006-07-16/07-19, Entebbe (UG), pp.764-795, 2006
Lewis R.W., Postek E.W., Gethin D.T., Yang X.S., Pao W.K.S., Chao L., Numerical methods in simulation of industrial processes, AET2006, First International Conference on Advances in Engineering and Technology, 2006-07-16/07-19, Entebbe (UG), pp.764-795, 2006

Abstract:
The paper deals with an overview of some industrial applications leading to a formulation for advanced numerical techniques. The applications comprise squeeze casting processes, forming of tablets and petroleum reservoir modelling. All of the problems lead to solutions of highly nonlinear, coupled sets of multiphysics equations.

Keywords:
squeeze forming, powder compaction, oil fields, coupled problems, thermomechanics, porous media, fluid flow, nonlinear solid mechanics, phase transformations, microstructural solidification models, numerical methods, contact problems, discrete elements, finite elements.

184.Ignaczak J., Plane harmonic waves in a microperiodic layered thermoelastic solid revisited, COMPOSITE INTERFACES, ISSN: 0927-6440, DOI: 10.1080/01495730390425080, Vol.27, No.9, pp.779-793, 2004
Ignaczak J., Plane harmonic waves in a microperiodic layered thermoelastic solid revisited, COMPOSITE INTERFACES, ISSN: 0927-6440, DOI: 10.1080/01495730390425080, Vol.27, No.9, pp.779-793, 2004

Keywords:
harmonic thermoelastic waves, microperiodic composites

185.Ignaczak J., Plane harmonic waves in a microperiodic layered infinite thermoelastic solid, COMPOSITE INTERFACES, ISSN: 0927-6440, DOI: 10.1080/714050871, Vol.26, No.11, pp.1033-1054, 2003
186.Ignaczak J., Saint-venant's principle for a microperiodic composite thermoelastic semispace: the dynamical refined average theory, COMPOSITE INTERFACES, ISSN: 0927-6440, DOI: 10.1080/01495730290074649, Vol.25, No.11, pp.1065-1079, 2002
187.Ignaczak J., A spatial decay estimate for transient thermoelastic process in a composite semispace, COMPOSITE INTERFACES, ISSN: 0927-6440, DOI: 10.1080/014957300280533, Vol.23, No.1, pp.1-14, 2000
188.Ignaczak J., Saint-venant type decay estimates for transient heat conduction in a composite rigid semispace, COMPOSITE INTERFACES, ISSN: 0927-6440, DOI: 10.1080/01495739808956144, Vol.21, No.3, pp.185-204, 1998
189.Ignaczak J., Baczyński Z.F., On a refined heat conduction theory for microperiodic layered solids, COMPOSITE INTERFACES, ISSN: 0927-6440, DOI: 10.1080/01495739708956127, Vol.20, pp.749-771, 1997
Ignaczak J., Baczyński Z.F., On a refined heat conduction theory for microperiodic layered solids, COMPOSITE INTERFACES, ISSN: 0927-6440, DOI: 10.1080/01495739708956127, Vol.20, pp.749-771, 1997

Abstract:
A refined averaged theory of a rigid heat conductor with a microperiodic structure is used to solve a one-dimensional initial boundary value problem ofheat conduction in a periodically layeredplate with a largenumber of homogeneous isotropic layers. A uniqueness theorem for the averaged problem is proved, and two closed-form solutions for a periodically
layered semispace are obtained. One of the two solutions represents the temperature
field in the layered semispace due to a sudden heating of the boundary plane, while the
other stands for the temperaturefield in the layeredsemispace produced by laser surface
heating. Numerical examples are included.

190.Ignaczak J., Hetnarski R., On solition-like thermoelastic waves, COMPOSITE INTERFACES, ISSN: 0927-6440, DOI: 10.1080/00036819708840557, Vol.65, No.1, pp.183-204, 1997
191.Postek E., Kleiber M., Design sensitivity of reinforced concrete plate/shell structures, CMM1995, XII Polish Conference on Computer Methods in Mechanics, 1995-05-09/05-13, Warszawa Zegrze (PL), pp.279-280, 1995
Postek E., Kleiber M., Design sensitivity of reinforced concrete plate/shell structures, CMM1995, XII Polish Conference on Computer Methods in Mechanics, 1995-05-09/05-13, Warszawa Zegrze (PL), pp.279-280, 1995

Abstract:
Design sensitivity gradients are believed to have great significance in realistic asscsment of structural response. Sensitivity techniques form a tool to follow changes in structural behaviour caused by variations of design parameters. The sensitivity gradients make it also possible to investigate the influence of different type of material or geometrical imperfections on the structural response. One of the first papers considering the design sensitivity analysis (DSA) was presented by Zienkiewicz and Campbell |lj. Recently, efforts of the investigators are mostly focused on the r.onlinear performance of structures. The total Lagrangian formulation with the computer Implementation in Adina was presented in ]2]. A formulation considering path-dependent problems was given in [3] and the updated Lagrangian formulation of the design sensitivity problems for arbitrary nonlinearities was given in [4]. Applications of the DSA to the slate estimation of complex structures were presented in |5). The response of reinforced concrete structures should always be considered nonlinear and thus it may be used as an example illustrating the theory of design sensitivity for nonlinear systems. This paper deals with the design sensitivity of reinforced plate and shell structures. References 1. 0. C. Zicnkiowicz, J.S. Campbell, Shape optimization and sequential linear programmiri R. II. Gallagher and O.C. Xienkicwicz, eds Optimum Structural Design, Wiley, 1973. 2. M. Ilaririan, J.B. Cardoso, J.S. Arora, Use of ADINA for design optimization of nonlinear structures, C'omput. Struct., 26 (1987), pp. 123-133. 3. C.A. Vidal, R.I3. Ilaber, Design sensitivity analysis for rate independent elasl.opla.stjr Comp. Mcth. Appl. Mcch. Eng., 107 (1993), pp. 393-431. 4. M. Kleiber, Shape and nonshapc structural design sensitivity analysis for problems w;; any material .and kinematic nonlincarity, Comp. Mclh. Appl. Eng., 108 (1993), pp. 73-97 5. M. Kleiber, T.D. Hien, E. Postek, Incremental finite eleirint sensitivity analysis for non-linear mechanics applications, Int. .!. Num. Me/It. Eng., 37 (1994), pp. 3291-3308.

Keywords:
parameter sensitivity, plate-shell structures, nonlinear analysis

192.Plaut R.H., Mróz Z., Upheaval Buckling of a Mechanism under External Pressure and Compressive Loading, International Journal of Mechanical Engineering Education, ISSN: 0306-4190, DOI: 10.1177/030641909402200201, Vol.22, No.2, pp.79-82, 1994
Plaut R.H., Mróz Z., Upheaval Buckling of a Mechanism under External Pressure and Compressive Loading, International Journal of Mechanical Engineering Education, ISSN: 0306-4190, DOI: 10.1177/030641909402200201, Vol.22, No.2, pp.79-82, 1994

Abstract:
A mechanical or structural element often buckles when it is compressed beyond a certain amount. Constraints may raise the value of the critical compressive load. In some cases a constraint may completely prevent the occurrence of buckling. This situation is demonstrated here by a simple two-bar model that rests on a rigid foundation and is subjected to pressure and compressive loading. If the system is ‘perfect’, buckling is not possible. However, if the foundation is not flat, or if the load is applied eccentrically, a sudden jump in deflection may occur as the load is increased.

193.Postek E., Rojek J., Antúnez H.J., Nonlinear static analysis of a guyed mast with finite element method, CMM1993, XI Polish Conference on Computer Methods in Mechanics, 1993-05-11/05-14, Kielce-Cedzyna (PL), pp.743-750, 1993
Postek E., Rojek J., Antúnez H.J., Nonlinear static analysis of a guyed mast with finite element method, CMM1993, XI Polish Conference on Computer Methods in Mechanics, 1993-05-11/05-14, Kielce-Cedzyna (PL), pp.743-750, 1993

Abstract:
This paper deals with numerical aspects of nonlinear static analysis of a guyed mast of 649 m height. A concept of a new structure constructed of solid bars instead of tubes is analyzed. Due to decrease of member diameters the wind load declines, thus the horizontal displacements are smaller. A few structural variants of the proposed mast are calculated.

Keywords:
guyed mast, nonlinear analysis, tendons

194.Kacprzyk Z., Postek E., Biblioteka izoparametrycznych elementów skończonych systemu FEAS, Metody Komputerowe w Inżynierii Lądowej, ISSN: 0867-5007, Vol.2, No.3, pp.89-108, 1993
Kacprzyk Z., Postek E., Biblioteka izoparametrycznych elementów skończonych systemu FEAS, Metody Komputerowe w Inżynierii Lądowej, ISSN: 0867-5007, Vol.2, No.3, pp.89-108, 1993

Abstract:
W artykule przedstawiona została biblioteka izoparametrycznych elementów skończonych opartych o paraboliczinee funkcje ksztaltu. W bibliotece zawarte zostały elementy tarczowe o liczbie węzłów od 4 do 8, bryłowe o liczbie węzłów od 8 do 20, 4 i 8 węzłowe elementy płyyty Mindlina, 3 węzłowy element powtoki osiowo-symetrycznej oraz 8 węzłowy element typu Ahmada. Przedstawiona biblioteka implementowana jest w systemie analizy konstrukcji inżynierskich FEAS i znajdzie sie ona w nowej wersji systemu. Konstrukcje mogq być modelowane przy użyciu elementów znajdujqcych się w tzw. bibliotece inżynierskiej skladającej się z elementów, których macierze sztywności obliczone zostaly analitycznie oraz w bibliotece , parabolicznej. W tym wypadku jednak za poprawność modelu odpowiada calkowicie użytkownik. Nowa biblioteka systemu wykorzystywana będzie zarówno w obliczeniach inżynierskich jak i w procesie nauczania mechaniki na Wydziale Inżynierii Lądowej.

Keywords:
elementy paraboliczne, metoda elementĂłw skończonych, dydaktyka

195.Kleiber M., Hien T.D., Postek E., Structural Design Sensitivity Analysis by Incremental Procedures, CMM10, X Polish Conference Computer Methods in Mechanics, 1991-05-14/05-17, Swinoujscie (PL), pp.357-364, 1991
Kleiber M., Hien T.D., Postek E., Structural Design Sensitivity Analysis by Incremental Procedures, CMM10, X Polish Conference Computer Methods in Mechanics, 1991-05-14/05-17, Swinoujscie (PL), pp.357-364, 1991

Abstract:
An incremental formulation based on the Taylor's expansion for nonlinear design sensitivity problems is developed. Computational aspects are discussed. A few numerical benchmark problems illustrate the paper.

Keywords:
design sensitivity, nonlinear geometry, incremental procedure