Publications reported by three months

1.Jurczak G., Dłużewski P., Finite element modelling of threading dislocation effect on polar GaN/AlN quantum dot, PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, ISSN: 1386-9477, DOI: 10.1016/j.physe.2017.08.018, Vol.95, pp.11-15, 2018
Jurczak G., Dłużewski P., Finite element modelling of threading dislocation effect on polar GaN/AlN quantum dot, PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, ISSN: 1386-9477, DOI: 10.1016/j.physe.2017.08.018, Vol.95, pp.11-15, 2018

Abstract:
In this paper the effect of adjacent threading dislocation at the edge of the GaN/AlN quantum dot is analysed by use of the finite element analysis. Elastic as well electric effects related to dislocation core are taken into account. Two types of threading dislocations: edge- and screw-type, common for III-nitride epitaxial layers, are considered. Also, three different QD geometries are considered to estimate the impact of the threading dislocation on the quantum heterostructure. It is demonstrated that the local elastic and electric fields around dislocation affect local piezoelectric fields built-in the quantum dot. Local lattice deformation near the dislocation core reduce residual strains in the quantum dot. It is prominent in the case of edge-type dislocation. The presence of an electric charge along dislocation line provides significant shift of the total potential towards the negative values. However, estimated difference in band-to-band transition energy for edge- and screw-type dislocations are rather small, what suggest low sensitivity to the charge density along dislocation line. Unexpectedly, local strain field around the edge-type dislocation, slightly compensate the negative affect of the electrostatic potential.

Keywords:
Quantum dot, Threading dislocation, Piezoelectricity, Finite element modelling

2.Pierini F., Lanzi M., Nakielski P., Pawłowska S., Urbanek O., Zembrzycki K., Kowalewski T.A., Single-Material Organic Solar Cells Based on Electrospun Fullerene-Grafted Polythiophene Nanofibers, Macromolecules, ISSN: 0024-9297, DOI: 10.1021/acs.macromol.7b00857, Vol.50, No.13, pp.4972-4981, 2017
Pierini F., Lanzi M., Nakielski P., Pawłowska S., Urbanek O., Zembrzycki K., Kowalewski T.A., Single-Material Organic Solar Cells Based on Electrospun Fullerene-Grafted Polythiophene Nanofibers, Macromolecules, ISSN: 0024-9297, DOI: 10.1021/acs.macromol.7b00857, Vol.50, No.13, pp.4972-4981, 2017

Abstract:
Highly efficient single-material organic solar cells (SMOCs) based on fullerene-grafted polythiophenes were fabricated by incorporating electrospun one-dimensional (1D) nanostructures obtained from polymer chain stretching. Poly(3-alkylthiophene) chains were chemically tailored in order to reduce the side effects of charge recombination which severely affected SMOC photovoltaic performance. This enabled us to synthesize a donor–acceptor conjugated copolymer with high solubility, molecular weight, regioregularity, and fullerene content. We investigated the correlations among the active layer hierarchical structure given by the inclusion of electrospun nanofibers and the solar cell photovoltaic properties. The results indicated that 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%). The enhanced performance may be attributed to well-packed and properly oriented polymer chains. Overall, our work demonstrates that the active material structure optimization obtained by including electrospun nanofibers plays a pivotal role in the development of efficient SMOCs and suggests an interesting perspective for the improvement of copolymer-based photovoltaic device performance using an alternative pathway.

3.Pisarski D., Decentralized stabilization of semi-active vibrating structures, MECHANICAL SYSTEMS AND SIGNAL PROCESSING, ISSN: 0888-3270, DOI: 10.1016/j.ymssp.2017.08.003, Vol.100, pp.694-705, 2017
Pisarski D., Decentralized stabilization of semi-active vibrating structures, MECHANICAL SYSTEMS AND SIGNAL PROCESSING, ISSN: 0888-3270, DOI: 10.1016/j.ymssp.2017.08.003, Vol.100, pp.694-705, 2017

Abstract:
A novel method of decentralized structural vibration control is presented. The control is assumed to be realized by a semi-active device. The objective is to stabilize a vibrating system with the optimal rates of decrease of the energy. The controller relies on an easily implemented decentralized switched state-feedback control law. It uses a set of communication channels to exchange the state information between the neighboring subcontrollers. The performance of the designed method is validated by means of numerical experiments performed for a double cantilever system equipped with a set of elastomers with controlled viscoelastic properties. In terms of the assumed objectives, the proposed control strategy significantly outperforms the passive damping cases and is competitive with a standard centralized control. The presented methodology can be applied to a class of bilinear control systems concerned with smart structural elements.

Keywords:
structural control, decentralized control, smart structures, modular structures, stabilization

4.Zajączkowska U., Kucharski S., Nowak Z., Grabowska K., Morphometric and mechanical characteristics of Equisetum hyemale stem enhance its vibration, PLANTA, ISSN: 0032-0935, DOI: 10.1007/s00425-017-2648-1, Vol.245, No.4, pp.835-848, 2017
Zajączkowska U., Kucharski S., Nowak Z., Grabowska K., Morphometric and mechanical characteristics of Equisetum hyemale stem enhance its vibration, PLANTA, ISSN: 0032-0935, DOI: 10.1007/s00425-017-2648-1, Vol.245, No.4, pp.835-848, 2017

Abstract:
The order of the internodes, and their geometry and mechanical characteristics influence the capability of theEquisetumstem to vibrate, potentially stimulating spore liberation at the optimum stress setting along the stem.
Equisetum hyemale L. plants represent a special example of cellular solid construction with mechanical stability achieved by a high second moment of area and relatively high resistance against local buckling. We proposed the hypothesis that the order of E. hyemale L. stem internodes, their geometry and mechanical characteristics influence the capability of the stem to vibrate, stimulating spore liberation at the minimum stress setting value along the stem. An analysis of apex vibration was done based on videos presenting the behavior of an Equisetum clump filmed in a wind tunnel and also as a result of excitation by bending the stem by 20°. We compared these data with the vibrations of stems of the same size but deprived of the three topmost internodes. Also, we created a finite element model (FEM), upon which we have based the ‘natural’ stem vibration as a copy of the real object, ‘random’ with reshuffled internodes and ‘uniform’, created as one tube with the characters averaged from all internodes. The natural internode arrangement influences the frequency and amplitude of the apex vibration, maintaining an equal stress distribution in the stem, which may influence the capability for efficient spore spreading.

Keywords:
Mechanical properties, Plant biomechanics, Segmented structure, Stem vibration, Stress distribution, Wind

5.Urbanek O., Sajkiewicz P., Pierini F., The effect of polarity in the electrospinning process on PCL/chitosan nanofibres' structure, properties and efficiency of surface modification, POLYMER, ISSN: 0032-3861, DOI: 10.1016/j.polymer.2017.07.064, Vol.124, pp.168-175, 2017
Urbanek O., Sajkiewicz P., Pierini F., The effect of polarity in the electrospinning process on PCL/chitosan nanofibres' structure, properties and efficiency of surface modification, POLYMER, ISSN: 0032-3861, DOI: 10.1016/j.polymer.2017.07.064, Vol.124, pp.168-175, 2017

Abstract:
The aim of this research was to study the effect of charge polarity applied to the spinning nozzle on the structure and properties of polycaprolactone/chitosan (PCL/CHT) blends, in particular the efficiency of further surface modification by chondroitin sulphate (CS). The observed differences in the morphology and properties of fibres formed at different polarities were interpreted in terms of molecular interactions occurring in the system. FTIR results indicate stronger PCL-chitosan interactions at negative polarity, resulting in lower PCL crystallinity and crystal size distribution determined by DSC, as well as lower wettability. The charge polarity influences PCL/CHT fibre morphology and tailors some of their properties, e.g. wettability, mechanical properties and the efficiency of surface modification. Better efficiency of CS attachment was observed at negative polarity using atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) is most probably related to higher chitosan content at the fibres' surface being attracted by the negative external potential.

Keywords:
Polycaprolactone/chitosan nanofibres, Charge potential effect in electrospinning, Polycaprolactone-chitosan interactions

6.Graczykowski C., Pawłowski P., Exact physical model of magnetorheological damper, Applied Mathematical Modelling, ISSN: 0307-904X, DOI: 10.1016/j.apm.2017.02.035, Vol.47, pp.400-424, 2017
Graczykowski C., Pawłowski P., Exact physical model of magnetorheological damper, Applied Mathematical Modelling, ISSN: 0307-904X, DOI: 10.1016/j.apm.2017.02.035, Vol.47, pp.400-424, 2017

Abstract:
This paper attempts to fill the gap in the literature by introducing and discussing an enhanced physical model of the MR damper. The essence of the presented model is to combine the effect of compressibility of the MR fluid enclosed in each chamber with the effect of blocking the flow between the chambers in the case of a low pressure difference. As it will be shown, the concurrence of both considered phenomena significantly affects mechanical behaviour of the damper, influences its dissipative characteristics, and in particular, it is the reason behind the distinctive ‘z-shaped’ force–velocity hysteresis loops observed in experiments. The paper presents explanation of the observed phenomena, detailed derivation of the thermodynamic equations governing response of the damper, their implementation for various constitutive models of the magnetorheological fluid and, finally, formulation of the corresponding reduced and parametric models. Experimental validation shows that proper identification of physical parameters of the proposed mathematical model yields the correct shapes of force–velocity hysteresis loops.

Keywords:
Magnetorheological fluid dampers, Smart fluids, Hysteresis modelling

7.Zieliński T.G., Microstructure representations for sound absorbing fibrous media: 3D and 2D multiscale modelling and experiments, JOURNAL OF SOUND AND VIBRATION, ISSN: 0022-460X, DOI: 10.1016/j.jsv.2017.07.047, Vol.409, pp.112-130, 2017
Zieliński T.G., Microstructure representations for sound absorbing fibrous media: 3D and 2D multiscale modelling and experiments, JOURNAL OF SOUND AND VIBRATION, ISSN: 0022-460X, DOI: 10.1016/j.jsv.2017.07.047, Vol.409, pp.112-130, 2017

Abstract:
The paper proposes and investigates computationally-efficient microstructure representations for sound absorbing fibrous media. Three-dimensional volume elements involving non-trivial periodic arrangements of straight fibres are examined as well as simple two-dimensional cells. It has been found that a simple 2D quasi-representative cell can provide similar predictions as a volume element which is in general much more geometrically accurate for typical fibrous materials. The multiscale modelling allowed to determine the effective speeds and damping of acoustic waves propagating in such media, which brings up a discussion
on the correlation between the speed, penetration range and attenuation of sound waves. Original experiments on manufactured copper-wire samples are presented and the microstructure-based calculations of acoustic absorption are compared with the corresponding experimental results. In fact, the comparison suggested the microstructure modifications leading to representations with non-uniformly distributed fibres.

Keywords:
sound absorption, fibrous materials, multiscale modelling, microstructure representations

8.Banach Z., Larecki W., Kershaw-type transport equations for fermionic radiation, ZEITSCHRIFT FUR ANGEWANDTE MATHEMATIK UND PHYSIK ZAMP, ISSN: 0044-2275, DOI: 10.1007/s00033-017-0847-z, Vol.68, No.4, pp.100-1-100-24, 2017
Banach Z., Larecki W., Kershaw-type transport equations for fermionic radiation, ZEITSCHRIFT FUR ANGEWANDTE MATHEMATIK UND PHYSIK ZAMP, ISSN: 0044-2275, DOI: 10.1007/s00033-017-0847-z, Vol.68, No.4, pp.100-1-100-24, 2017

Abstract:
Besides the maximum entropy closure procedure, other procedures can be used to close the systems of spectral
moment equations. In the case of classical and bosonic radiation, the closed-form analytic Kershaw-type and B-distribution closure procedures have been used. It is shown that the Kershaw-type closure procedure can also be applied to the spectra moment equations of fermionic radiation. First, a description of the Kershaw-type closure for the system consisting of an arbitrary number of one-dimensional moment equations is presented. Next, the Kershaw-type two-field and three-field transport equations for fermionic radiation are analyzed. In the first case, the independent variables are the energy density and the heat flux. The second case includes additionally the flux of the heat flux as an independent variable. The generalization of the former two-field case to three space dimensions is also presented. The fermionic Kershaw-type closures differ from those previously derived for classical and bosonic radiation. It is proved that the obtained one-dimensional systems of transport equations are strictly hyperbolic and causal. The fermionic Kershaw-type closure functions behave qualitatively in the same way as the fermionic maximum entropy closure functions, but attain different numerical values.

Keywords:
Fermionic radiation, Moment equations, Moment realizability problem, Kershaw-type closure, Three-moment transport.

9.Jarecki L., Misztal-Faraj B., Non-linear stress-orientation behavior of flexible chain polymers under fast elongational flow, EUROPEAN POLYMER JOURNAL, ISSN: 0014-3057, DOI: 10.1016/j.eurpolymj.2017.08.028, Vol.95, pp.368-381, 2017
Jarecki L., Misztal-Faraj B., Non-linear stress-orientation behavior of flexible chain polymers under fast elongational flow, EUROPEAN POLYMER JOURNAL, ISSN: 0014-3057, DOI: 10.1016/j.eurpolymj.2017.08.028, Vol.95, pp.368-381, 2017

Abstract:
Closed-form analytical formulas are proposed for non-linear stress-orientation relation valid in the entire range of tensile stresses, intermediate and high, basing on the inverse Langevin chain statistics. Tensile force and orientation characteristics for single, flexible chain macromolecule are reconsidered in a closed-form Padè approximation of the inverse Langevin function in the entire range of chain extensions, as well as the dynamics of molecular deformation and orientation
for systems of chains subjected to uniaxial elongational flow. Average stress and orientation tensors, not collinear in the non-linear range, as well as the tensile stress and axial orientation factor of the chain segments in the system are calculated. For the intermediate tensile stresses, the closed-form formula is derived in the first non-Gaussian term approximation of the inverse Langevin function with the assumption of dominating longitudinal elongation of the chains. The high-stress non-linearity formula is derived with the Padè and Peterlin modulus approximations and aligned chain end-to-end vectors by the flow. Both formulas are validated by exact numerical calculations without the assumptions and influence of the approximations is estimated. Ranges of applicability of the formulas are illustrated and examples of their application are presented.

Keywords:
Molecular orientation, Tensile stress, Non-linear stress-orientation behavior, Elongational flow, Langevin chain statistics

10.Chmielewski M., Pietrzak K., Strojny-Nędza A., Jarząbek D., Nosewicz S., Investigations of interface properties in copper-silicon carbide composites, ARCHIVES OF METALLURGY AND MATERIALS, ISSN: 1733-3490, DOI: 10.1515/amm-2017-0200, Vol.62, No.2B, pp.1315-1318, 2017
Chmielewski M., Pietrzak K., Strojny-Nędza A., Jarząbek D., Nosewicz S., Investigations of interface properties in copper-silicon carbide composites, ARCHIVES OF METALLURGY AND MATERIALS, ISSN: 1733-3490, DOI: 10.1515/amm-2017-0200, Vol.62, No.2B, pp.1315-1318, 2017

Abstract:
This paper analyses the technological aspects of the interface formation in the copper-silicon carbide composite and its effect on the material’s microstructure and properties. Cu-SiC composites with two different volume content of ceramic reinforcement were fabricated by hot pressing (HP) and spark plasma sintering (SPS) technique. In order to protect SiC surface from its decomposition, the powder was coated with a thin tungsten layer using plasma vapour deposition (PVD) method. Microstructural analyses provided by scanning electron microscopy revealed the significant differences at metal-ceramic interface. Adhesion force and fracture strength of the interface between SiC particles and copper matrix were measured. Thermal conductivity of composites was determined using laser flash method. The obtained results are discussed with reference to changes in the area of metal-ceramic boundary.

Keywords:
copper matrix composites, silicon carbide, interface, thermal conductivity, adhesion

11.Strojny-Nędza A., Pietrzak K., Teodorczyk M., Basista M., Węglewski W., Chmielewski M., Influence of Material Ccating on the heat Transfer in a layered Cu-SiC-Cu Systems, ARCHIVES OF METALLURGY AND MATERIALS, ISSN: 1733-3490, DOI: 10.1515/amm-2017-0199, Vol.62, No.2B, pp.1311-1314, 2017
Strojny-Nędza A., Pietrzak K., Teodorczyk M., Basista M., Węglewski W., Chmielewski M., Influence of Material Ccating on the heat Transfer in a layered Cu-SiC-Cu Systems, ARCHIVES OF METALLURGY AND MATERIALS, ISSN: 1733-3490, DOI: 10.1515/amm-2017-0199, Vol.62, No.2B, pp.1311-1314, 2017

Abstract:
This paper describes the process of obtaining Cu-SiC-Cu systems by way of spark plasma sintering. A monocrystalline form of silicon carbide (6H-SiC type) was applied in the experiment. Additionally, silicon carbide samples were covered with a layer of tungsten and molybdenum using chemical vapour deposition (CVD) technique. Microstructural examinations and thermal properties measurements were performed. A special attention was put to the metal-ceramic interface. During annealing at a high temperature, copper reacts with silicon carbide. To prevent the decomposition of silicon carbide two types of coating (tungsten and molybdenum) were applied. The effect of covering SiC with the aforementioned elements on the composite’s thermal conductivity was analyzed. Results were compared with the numerical modelling of heat transfer in Cu-SiC-Cu systems. Certain possible reasons behind differences in measurements and modelling results were discussed.

Keywords:
copper matrix composites, silicon carbide, interface, thermal conductivity, modelling

12.Maździarz M., Mrozek A., Kuś W., Burczyński T., First-principles study of new X-graphene and Y-graphene polymorphs generated by the two stage strategy, MATERIALS CHEMISTRY AND PHYSICS, ISSN: 0254-0584, DOI: 10.1016/j.matchemphys.2017.08.066, Vol.202, pp.7-14, 2017
Maździarz M., Mrozek A., Kuś W., Burczyński T., First-principles study of new X-graphene and Y-graphene polymorphs generated by the two stage strategy, MATERIALS CHEMISTRY AND PHYSICS, ISSN: 0254-0584, DOI: 10.1016/j.matchemphys.2017.08.066, Vol.202, pp.7-14, 2017

Abstract:
Two potentially new, 2D-graphene-like materials have been generated by the two stage searching strategy combining molecular and ab initio approach. The two candidates obtained from the evolutionary based algorithm and molecular calculations were then in depth analysed using first-principles Density Functional Theory from the mechanical, structural, phonon and electronic properties point of view. Both proposed polymorphs of graphene (oP8-P2mm) are mechanically and dynamically stable and can be metallic-like.

Keywords:
Carbon; Graphene; Ab initio calculations; Mechanical properties; Elastic properties

13.Pierini F., Lanzi M., Nakielski P., Kowalewski T.A., Electrospun Polyaniline-Based Composite Nanofibers: Tuning the Electrical Conductivity by Tailoring the Structure of Thiol-Protected Metal Nanoparticles, Journal of Nanomaterials, ISSN: 1687-4110, DOI: 10.1155/2017/6142140, Vol.2017, pp.1-10, 2017
Pierini F., Lanzi M., Nakielski P., Kowalewski T.A., Electrospun Polyaniline-Based Composite Nanofibers: Tuning the Electrical Conductivity by Tailoring the Structure of Thiol-Protected Metal Nanoparticles, Journal of Nanomaterials, ISSN: 1687-4110, DOI: 10.1155/2017/6142140, Vol.2017, pp.1-10, 2017

Abstract:
Composite nanofibers made of a polyaniline-based polymer blend and different thiol-capped metal nanoparticles were prepared using ex situ synthesis and electrospinning technique. The effects of the nanoparticle composition and chemical structure on the electrical properties of the nanocomposites were investigated. This study confirmed that Brust’s procedure is an effective method for the synthesis of sub-10 nm silver, gold, and silver-gold alloy nanoparticles protected with different types of thiols. Electron microscopy results demonstrated that electrospinning is a valuable technique for the production of composite nanofibers with similar morphology and revealed that nanofillers are well-dispersed into the polymer matrix. X-ray diffraction tests proved the lack of a significant influence of the nanoparticle chemical structure on the polyaniline chain arrangement. However, the introduction of conductive nanofillers in the polymer matrix influences the charge transport noticeably improving electrical conductivity. The enhancement of electrical properties is mediated by the nanoparticle capping layer structure. The metal nanoparticle core composition is a key parameter, which exerted a significant influence on the conductivity of the nanocomposites. These results prove that the proposed method can be used to tune the electrical properties of nanocomposites.

14.Sławianowski J.J., Kovalchuk V., Gołubowska B., Martens A., Rożko E.E., Quantized mechanics of affinely-rigid bodies, MATHEMATICAL METHODS IN THE APPLIED SCIENCES, ISSN: 0170-4214, DOI: 10.1002/mma.4501, pp.1-19, 2017
Sławianowski J.J., Kovalchuk V., Gołubowska B., Martens A., Rożko E.E., Quantized mechanics of affinely-rigid bodies, MATHEMATICAL METHODS IN THE APPLIED SCIENCES, ISSN: 0170-4214, DOI: 10.1002/mma.4501, pp.1-19, 2017

Abstract:
In this paper, we develop the main ideas of the quantized version of affinely rigid (homogeneously deformable) motion. We base our consideration on the usual Schrödinger formulation of quantum mechanics in the configurationmanifold, which is given, in our case, by the affine group or equivalently by the semi-direct product of the linear group GL(n,R) and the space of translations R^n, where n equals the dimension of the “physical space.” In particular, we discuss the problem of dynamical invariance of the kinetic energy under the action of the whole affine group, not only under the isometry subgroup. Technically, the treatment is based on the 2-polar decomposition of the matrix of the internal configuration and on the Peter-Weyl theory of generalized Fourier series on Lie groups. One can hope that our results may be applied in quantum problems of elastic media and microstructured continua.

Keywords:
Homogeneously deformable body, Peter-Weyl analysis, Schrödinger quantization.

15.Basista M., Jakubowska J., Węglewski W., Processing Induced Flaws in Aluminum–Alumina Interpenetrating Phase Composites, Advanced Engineering Materials, ISSN: 1438-1656, DOI: 10.1002/adem.201700484, pp.1700484-1-1700484-14, 2017
Basista M., Jakubowska J., Węglewski W., Processing Induced Flaws in Aluminum–Alumina Interpenetrating Phase Composites, Advanced Engineering Materials, ISSN: 1438-1656, DOI: 10.1002/adem.201700484, pp.1700484-1-1700484-14, 2017

Abstract:
This review paper deals with flaws in aluminum–alumina composites and FGMs induced by their manufacturing processes. Aluminum–alumina composites have been studied for many years as potentially interesting materials for applications, for example, in the automotive sector due to their enhanced mechanical strength, wear resistance, good heat conductivity and low specific weight. The focus here is on the interpenetrating phase composites (IPCs) manufactured by infiltration of porous alumina preforms with molten aluminum alloys. The primary objective is to provide an updated overview of research findings on a variety of flaws occurring at different stages of the manufacturing processes. Some precautions on how to avoid processing induced flaws in aluminum–alumina bulk composites and FGMs are mentioned.

16.Kukla D., Brynk T., Pakieła Z., Assessment of Fatigue Resistance of Aluminide Layers on MAR 247 Nickel Super Alloy with Full-Field Optical Strain Measurements, Journal of Materials Engineering and Performance, ISSN: 1059-9495, DOI: 10.1007/s11665-017-2767-7, pp.1-12, 2017
Kukla D., Brynk T., Pakieła Z., Assessment of Fatigue Resistance of Aluminide Layers on MAR 247 Nickel Super Alloy with Full-Field Optical Strain Measurements, Journal of Materials Engineering and Performance, ISSN: 1059-9495, DOI: 10.1007/s11665-017-2767-7, pp.1-12, 2017

Abstract:
This work presents the results of fatigue tests of MAR 247 alloy flat specimens with aluminides layers of 20 or 40 µm thickness obtained in CVD process. Fatigue test was conducted at amplitude equal to half of maximum load and ranging between 300 and 650 MPa (stress asymmetry ratio R = 0, frequency f = 20 Hz). Additionally, 4 of the tests, characterized by the highest amplitude, were accompanied with non-contact strain field measurements by means of electronic speckle pattern interferometry and digital image correlation. Results of these measurements allowed to localize the areas of deformation concentration identified as the damage points of the surface layer or advanced crack presence in core material. Identification and observation of the development of deformation in localization areas allowed to assess fatigue-related phenomena in both layer and substrate materials.

Keywords:
aluminide layer, fatigue testing, full-field optical strain measurements, super nickel alloy

17.Byra M., Kruglenko E., Gambin B., Nowicki A., Temperature Monitoring during Focused Ultrasound Treatment by Means of the Homodyned K Distribution, ACTA PHYSICA POLONICA A, ISSN: 0587-4246, DOI: 10.12693/APhysPolA.131.1525, Vol.131, No.6, pp.1525-1528, 2017
Byra M., Kruglenko E., Gambin B., Nowicki A., Temperature Monitoring during Focused Ultrasound Treatment by Means of the Homodyned K Distribution, ACTA PHYSICA POLONICA A, ISSN: 0587-4246, DOI: 10.12693/APhysPolA.131.1525, Vol.131, No.6, pp.1525-1528, 2017

Abstract:
Temperature monitoring is essential for various medical treatments. In this work, we investigate the impact
of temperature on backscattered ultrasound echo statistics during a high intensity focused ultrasound treatment. A tissue mimicking phantom was heated with a spherical ultrasonic transducer up to 56 _C in order to imitate tissue necrosis. During the heating, an imaging scanner was used to acquire backscattered echoes from the heated region. These data was then modeled with the homodyned K distribution. We found that the best temperature indicator can be obtained by combining two parameters of the model, namely the backscattered echo mean intensity and the effective number of scatterers per resolution cell. Next, ultrasonic thermometer was designed and used to create a map of the temperature induced within the tissue phantom during the treatment

Keywords:
Temperature monitoring, homodyned K distribution, focused ultrasound

18.Urbanek O., Sajkiewicz P., Biomimetically surface modified fibres for cartilage regeneration, TERMIS-EU 2017, European Chapter Meeting of the Tissue Engineering and Regenerative Medicine International Society 2017, 2017-06-26/06-30, Davos (CH), pp.P666, 2017
19.Nakielski P., Pierini F., Piechocka I.K., Blood clotting in the contact with nanofibers, NanoTech, NanoTech Poland International Conference & Exhibition, 2017-06-01/06-03, Poznań (PL), pp.178-178, 2017
Nakielski P., Pierini F., Piechocka I.K., Blood clotting in the contact with nanofibers, NanoTech, NanoTech Poland International Conference & Exhibition, 2017-06-01/06-03, Poznań (PL), pp.178-178, 2017

Abstract:
Nanofibers have received considerable attention in the past years, mainly due to their vast application in medicine [1]. One of the fastest growing areas of application are wound dressings and hemostats. Among the major causes of death from trauma, massive bleeding is responsible for 30 – 40% of mortality. In the hospital, massive bleeding are the second most common cause of death (22%) just after cardiac factors (33%) [2].
Despite a large number of experiments done in the topic of blood-biomaterial interactions, coagulation mechanisms are still not fully understood. Therefore, the main objective of our work is the analysis of protein adsorption, platelet adhesion and aggregation, and blood plasma coagulation in the contact with polymer nanofibers. Various synthetic polymers, their blends with natural polymers of confirmed hemostatic effect e.g. collagen and gelatine, and additionally nanofibers made of chitosan are investigated for their potential to stop bleeding. In the final, controlled release of drugs affecting coagulation cascade will be an important step providing accelerated blood clot formation.

20.Dulnik J., Kołbuk D., Denis P., Sajkiewicz P., Cellular studies of electrospun PCL/biocomponent nanofibers from alternative and traditional solvents, TERMIS-EU 2017, European Chapter Meeting of the Tissue Engineering and Regenerative Medicine International Society 2017, 2017-06-26/06-30, Davos (CH), pp.P715, 2017
21.Chrzanowska-Giżyńska J., Hoffman J., Mościcki T., Comparison of tungsten borides layers deposited by laser pulse and magnetron sputtering, CNM, 5th Conference on Nano- and Micromechanics, 2017-07-04/07-06, Wrocław (PL), No.O-26, pp.92-93, 2017
Chrzanowska-Giżyńska J., Hoffman J., Mościcki T., Comparison of tungsten borides layers deposited by laser pulse and magnetron sputtering, CNM, 5th Conference on Nano- and Micromechanics, 2017-07-04/07-06, Wrocław (PL), No.O-26, pp.92-93, 2017

Keywords:
magnetron sputtering, pulsed laser deposition, superhard materials, tungsten borides

22.Sadowski P., Kowalczyk-Gajewska K., Stupkiewicz S., Micromechanical modelling of elasto-plastic composites: efficient and robust finite-element implementation of Mori-Tanaka model, CNM, 5th Conference on Nano- and Micromechanics, 2017-07-04/07-06, Wrocław (PL), No.O-08, pp.31-33, 2017
Sadowski P., Kowalczyk-Gajewska K., Stupkiewicz S., Micromechanical modelling of elasto-plastic composites: efficient and robust finite-element implementation of Mori-Tanaka model, CNM, 5th Conference on Nano- and Micromechanics, 2017-07-04/07-06, Wrocław (PL), No.O-08, pp.31-33, 2017

Keywords:
Mean-field homogenization, Mori-Tanaka method, Composite materials, Finite element method

23.Pawełek A., Ozgowicz W., Ranachowski Z., Kúdela S., Piątkowski A., Kúdela S.Jr., Ranachowski P., Behaviour of Acoustic Emission in Deformation and Microcracking Processes of Mg Alloys Matrix Composites Subjected to Compression Tests, ARCHIVES OF CURRENT RESEARCH INTERNATIONAL, ISSN: 2454-7077, DOI: 10.9734/ACRI/2017/34598, Vol.8, No.2, pp.1-13, 2017
Pawełek A., Ozgowicz W., Ranachowski Z., Kúdela S., Piątkowski A., Kúdela S.Jr., Ranachowski P., Behaviour of Acoustic Emission in Deformation and Microcracking Processes of Mg Alloys Matrix Composites Subjected to Compression Tests, ARCHIVES OF CURRENT RESEARCH INTERNATIONAL, ISSN: 2454-7077, DOI: 10.9734/ACRI/2017/34598, Vol.8, No.2, pp.1-13, 2017

Abstract:
Research results on both mechanical and acoustic emission (AE) behavior of Mg-Li and Mg-Al alloys matrix composites (AMC) reinforced with ceramic δ-Al2O3 or carbon fibers subjected to the channel-die compression at room and elevated temperatures are presented in this paper. The AE measurements at room temperature showed that, the effect of anisotropy of the fibres distribution (random planar distribution) with respect to the compression axis appeared in the most investigated composites, whereas the AE activity at 140°C revealed a two- range character and the rate of AE events at 140°C was higher than at room temperature. These effects are discussed in terms of both the differences in thermal expansion between the fibres and the matrix as well as the weakening of the coherency between the fibres and the matrix leading to stronger debonding effects at 140°C than at room temperature. The spectral analysis of AE signals was performed with the Windowed Fourier Transform method, which served to plot the spectral density of AE signal as a function of frequency. The alominous and corundum ceramics types were also investigated in order to illustrate the enhanced AE, which was related to the different crack paths in the final stages of the sample degradation. The results were also discussed on the basis of SEM images, including the in-situ observations of microcracking as well as the dislocation strain mechanisms and microcracking ones during the channel-die compression of the Mg-Li-Al AMC.

Keywords:
composites, fibres microcracking, acoustic emission, strain mechanisms, dislocations

24.Fantilli A.P., Jóźwiak-Niedźwiedzka D., Gibas K., Dulnik J., The compability between wool fibers and cementitious mortars, ICBBM & EcoGRAFI, Second International RILEM Conference on Bio-based Building Materials 1st Conference on ECOlogical valorisation of GRAnular and FIbrous materials, 2017-06-21/06-23, Clermont-Ferrand (FR), pp.42-47, 2017
Fantilli A.P., Jóźwiak-Niedźwiedzka D., Gibas K., Dulnik J., The compability between wool fibers and cementitious mortars, ICBBM & EcoGRAFI, Second International RILEM Conference on Bio-based Building Materials 1st Conference on ECOlogical valorisation of GRAnular and FIbrous materials, 2017-06-21/06-23, Clermont-Ferrand (FR), pp.42-47, 2017

Abstract:
The addition of natural fibers residue in cement based materials can be a sustainable technological alternative for traditional dispersed reinforcement, and can improve the performance of brittle matrix materials. The presence of a wool reinforcement can increase the fracture toughness and, at the same time, can reduce the environmental impact of cementitious mortars. The beneficial effects are similarly to those observed in presence of vegetal fibers (e.g., hemp), which have been largely investigated in the literature. However, there are some limits in the use of wool fibers due to their chemical compatibility with the cement matrix, as they can dissolve in alkaline environments. In the present paper, to investigate the compatibility between wool fibers and cementitious mortars, laboratory prototypes have been taken into consideration. Three series of wool-reinforced mortar beams have been cast and cured in water (20°C) or in dry conditions (temp. 20 °C, 50% R.H.) for some days. Portland-limestone cement CEM II has been used, whereas the content of fibers has been limited to about 1% in volume to maintain the workability of the mortars. To investigate the chemical compatibility, and the subsequent effects on the mechanical performances, prototypes have been tested in three point bending. After the mechanical test, the mortars microstructure was evaluated through SEM images and by thin section in transmitted light, in order to individuate a possible relationship between the dissolution of wool and curing conditions. The microstructure observation revealed the capability of wool fibers to bridge the cracks, and to reduce the brittleness of plain mortars. The differences in the mortars microstructure due to alternative curing conditions were also observed and described in the paper. Accordingly, wool could be effectively used to reduce the plastic shrinkage of cementbased composites, like the industrially manufactured polypropylene fibers.

Keywords:
Wool fibers, Plain cement-based mortar, Fiber-reinforced mortar, Polypropylene fibers, Three point bending tests, SEM analyses

25.Pieczyska E.A., Golasiński K., Staszczak M., Maj M., Furuta T., Kuramoto S., A thermomechanical analysis of high elasto-plastic properties of gum metal at various strain rates, M2D, 7th International Conference on Mechanics and Materials in Design, 2017-06-11/06-15, Albufeira (PT), No.7002, pp.131-132, 2017
Pieczyska E.A., Golasiński K., Staszczak M., Maj M., Furuta T., Kuramoto S., A thermomechanical analysis of high elasto-plastic properties of gum metal at various strain rates, M2D, 7th International Conference on Mechanics and Materials in Design, 2017-06-11/06-15, Albufeira (PT), No.7002, pp.131-132, 2017

Abstract:
Mechanical characteristics obtained by MTS testing machine and digital image correlation (DIC) algorithm as well as the related temperature changes in a new B-Ti alloy - Gum Metal, subjected to tension in a wide spectrum of the strain rates, are presented The fast and sensitive infrared camera ThermaCam Phoenix allowed estimating temperature changes accompanying the specimen deformation process in contactless manner. The obtained mechanical curves confirm an ultra-low elastic modulus and high strength of Gum Metal. Furthermore, it was presented how the stress-strain characteristics change from hardening to softening depending on the strain rate. The thermoelastic effect, estimated by the IR technique was discussed according to the Gum Metal yield point.

Keywords:
gum metal, titanium alloy, tension test, strain rate, thermomechanical coupling

26.Maździarz M., Rojek J., Nosewicz S., Estimation of micromechanical NiAl sintering model parameters from the Atomistic Simulations, VII International Conference on Coupled Problems in Science and Engineering, 2017-06-12/06-14, Rhodes Island (GR), pp.1-1, 2017
27.Maździarz M., Rojek J., Nosewicz S., Molecular dynamics study of self-diffusion in stoichiometric B2-NiAl, CMN2017, Congress on Numerical Methods in Engineering, 2017-07-03/07-05, Valencia (ES), pp.1373-1373, 2017
28.Dunić V., Slavković R., Pieczyska E., Thermo-mechanical numerical analysis of transformation-induced stress relaxation during pseudoelastic behavior of SMA, SEECCM, 4th South-East European Conference on Computational Mechanics, 2017-07-03/07-05, Kragujevac (XS), No.T.4.7, pp.28-1-28-6, 2017
Dunić V., Slavković R., Pieczyska E., Thermo-mechanical numerical analysis of transformation-induced stress relaxation during pseudoelastic behavior of SMA, SEECCM, 4th South-East European Conference on Computational Mechanics, 2017-07-03/07-05, Kragujevac (XS), No.T.4.7, pp.28-1-28-6, 2017

Abstract:
A stress relaxation phenomenon is observed by coupled thermo-mechanical numerical analysis of SMA subjected to uniaxial test. The thermo-mechanical coupling is realized in the partitioned approach. The software components for the structural analysis (PAKS) and the heat transfer (PAKT) based on the Finite Element Method (FEM) have been used. The latent heat production is correlated with the amount of the martensitic volume fraction. The thermo-mechanical numerical analysis of a belt type specimen has been investigated for the strain controlled loading with the break during the martensitic transformation. The thermally induced martensitic transformation induced the significant stress change during the loading break what was expected according to the experimental results from literature.

Keywords:
shape memory alloys, stress relaxation, thermo-mechanical coupling, phase transformation, partitioned coupling

29.Hron J., Miloš V., Průša V., Souček O., Tůma K., On thermodynamics of incompressible viscoelastic rate type fluids with temperature dependent material coefficients, INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS, ISSN: 0020-7462, DOI: 10.1016/j.ijnonlinmec.2017.06.011, Vol.95, pp.193-208, 2017
Hron J., Miloš V., Průša V., Souček O., Tůma K., On thermodynamics of incompressible viscoelastic rate type fluids with temperature dependent material coefficients, INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS, ISSN: 0020-7462, DOI: 10.1016/j.ijnonlinmec.2017.06.011, Vol.95, pp.193-208, 2017

Abstract:
We derive a class of thermodynamically consistent variants of Maxwell/Oldroyd-B type models for incompressible viscoelastic fluids. In particular, we study the models that allow one to consider temperature dependent material coefficients. This naturally calls for the formulation of a temperature evolution equation that would accompany the evolution equations for the mechanical quantities. The evolution equation for the temperature is explicitly formulated, and it is shown to be consistent with the laws of thermodynamics and the evolution equations for the mechanical quantities. The temperature evolution equation contains terms that are ignored or even not thought of in most of the practically oriented (computational) works dealing with this class of fluids. The impact of the additional terms in the temperature evolution equation on the flow dynamics is documented by the solution of simple initial/boundary value problems.

Keywords:
Maxwell fluid; Oldroyd-B fluid; Temperature dependent material coefficients; Thermodynamics; Cylindrical Couette flow; Biaxial extension; Numerical simulations

30.Wasilewski M., Pisarski D., Adaptive optimal control algorithm for vibrational systems under nonlinear friction, MMAR 2017, 22nd International Conference on Methods and Models in Automation and Robotics, 2017-08-28/08-31, Międzyzdroje (PL), pp.107-112, 2017
Wasilewski M., Pisarski D., Adaptive optimal control algorithm for vibrational systems under nonlinear friction, MMAR 2017, 22nd International Conference on Methods and Models in Automation and Robotics, 2017-08-28/08-31, Międzyzdroje (PL), pp.107-112, 2017

Abstract:
In this paper, a novel control algorithm for vibration attenuation is presented. The proposed scheme is developed to control linear systems with a presence of an external disturbance. The goal of the control is to steer the system to prescribed reference trajectory by minimizing associated quadratic performance index.
The synthesis of the control law consists of two steps. At the first step, past measures of disturbance are used to develop a local linear approximation of dynamics of the disturbance signal. Weights of the associated auto-regressive model are calculated by the least-square algorithm. At the second step, the calculated model is used to obtain a linear time-invariant approximation of the control system. The receding horizon control law is then calculated by using finite horizon Linear Quadratic Regulator. The algorithm is verified numerically for a torsional vibrating system under nonlinear, time-varying friction. The results of the simulation are compared to a standard Linear Quadratic Gaussian control.

31.Wasilewski M., Pisarski D., Konowrocki R., Bajer C.I., New efficient adaptive control of torsional vibrations induced by sudden nonlinear disturbances, CMM-2017, 22nd International Conference on Computer Methods in Mechanics, 2017-09-13/09-16, Lublin (PL), pp.1-2, 2017
Wasilewski M., Pisarski D., Konowrocki R., Bajer C.I., New efficient adaptive control of torsional vibrations induced by sudden nonlinear disturbances, CMM-2017, 22nd International Conference on Computer Methods in Mechanics, 2017-09-13/09-16, Lublin (PL), pp.1-2, 2017

Abstract:
The aim of this paper is to present a novel adaptive technique of control of the vibrating drilling systems. The algorithm constitutes an adaptive linear quadratic regulator that uses direct measurements of the disturbance to synthesize its linear dynamic approximation. This approach allows generating control law that includes the impact of the friction on the system dynamics and optimally steers the system to the desired trajectory. The effectiveness of the algorithm is validated via comprehensive numerical simulations of the control of the simplified drilling model. The results are compared to these obtained with the use of the Linear Quadratic Gaussian regulator.

32.Lumelskyj D., Rojek J., Banabic D., Lazarescu L., Detection of Strain Localization in Nakazima Formability Test - Experimental Research and Numerical Simulation, SHEMET17, 17th International Conference on Sheet Metal, 2017-04-10/04-12, Palermo (IT), DOI: 10.1016/j.proeng.2017.04.016, No.183, pp.89-94, 2017
Lumelskyj D., Rojek J., Banabic D., Lazarescu L., Detection of Strain Localization in Nakazima Formability Test - Experimental Research and Numerical Simulation, SHEMET17, 17th International Conference on Sheet Metal, 2017-04-10/04-12, Palermo (IT), DOI: 10.1016/j.proeng.2017.04.016, No.183, pp.89-94, 2017

Abstract:
This paper presents the investigation on detection of strain localization in experimental research and numerical simulation of sheet metal forming. Experimental tests and numerical simulations of the Nakazima test have been performed for the DC04 grade steel sheet. The onset of localized necking has been determined using the criterion based on analysis of the major principal strain and its first and second time derivatives in the most strained zone. The strain localization has been evaluated by the maximum of strain acceleration which corresponds to the inflection point of the strain velocity vs. time. The limit strains have been calculated numerically and experimentally for specimens undergoing deformation at different strain paths. It has been shown that the numerical model predicts formability limits close to the experimental results. Analyzed criterion can be used as a potential alternative tool to determine formability in standard finite element simulations of sheet forming processes.

Keywords:
sheet forming, formability, forming limit curve, numerical simulation

33.Jurczak G., Maździarz M., Dłużewski P., Finite element modelling of threading dislocation effect on GaN/AlN quantum dot, ICMM5, 5th International Conference on Material Modeling, 2017-06-14/06-16, Rome (IT), pp.1-1, 2017
Jurczak G., Maździarz M., Dłużewski P., Finite element modelling of threading dislocation effect on GaN/AlN quantum dot, ICMM5, 5th International Conference on Material Modeling, 2017-06-14/06-16, Rome (IT), pp.1-1, 2017

Keywords:
Quantum dot, Threading dislocation, Piezoelectricity, Finite element modelling