Institute of Fundamental Technological Research
Polish Academy of Sciences

Latest Publications

Publications reported by three months

1. Piranda B., Chodkiewicz P., Hołobut P., Bordas S.P.A., Bourgeois J., Lengiewicz J., Distributed prediction of unsafe reconfiguration scenarios of modular robotic programmable matter, IEEE TRANSACTIONS ON ROBOTICS, ISSN: 1552-3098, DOI: 10.1109/TRO.2021.3074085, pp.1-8, 2021nota 7134

We present a distributed framework for predicting whether a planned reconfiguration step of a modular robot will mechanically overload the structure, causing it to break or lose stability under its own weight. The algorithm is executed by the modular robot itself and based on a distributed iterative solution of mechanical equilibrium equations derived from a simplified model of the robot. The model treats intermodular connections as beams and assumes no-sliding contact between the modules and the ground. We also provide a procedure for simplified instability detection. The algorithm is verified in the Programmable Matter simulator VisibleSim, and in real-life experiments on the modular robotic system Blinky Blocks.

distributed algorithms, modular robots, mechanical constraints, programmable matter, self-reconfiguration

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2. Venegas R., Zieliński T.G., Núñez G., Bécot F.-X., Acoustics of porous composites, COMPOSITES PART B-ENGINEERING, ISSN: 1359-8368, DOI: 10.1016/j.compositesb.2021.109006, Vol.220, pp.109006-1-14, 2021nota 7141

Acoustic wave propagation in porous composites is investigated in this paper. The two-scale asymptotic homogenisation method is used to obtain the macroscopic description of sound propagation in such composites. The developed theory is both exemplified by introducing analytical models for the effective acoustical properties of porous composites with canonical inclusion patterns (i.e. a porous matrix with a periodic array of cylindrical or spherical inclusions) and validated by comparing the models predictions with the results of direct finite-element simulations and experimental testing, showing good agreement in all cases. It is concluded that the developed theory correctly captures the acoustic interaction between the constituents of the porous composite and elucidates the physical mechanisms underlying the dissipation of sound energy in such composites. These correspond to classical visco-thermal dissipation in the porous constituents, together with, for the case of composites made from constituents characterised by highly contrasted permeabilities, pressure diffusion which provides additional and tunable sound energy dissipation. In addition, this work determines the conditions for which a rigidly-backed porous composite layer can present improved sound absorption performance in comparison with that of layers made from their individual constituents. Hence, the presented results are expected to guide the rational design of porous composites with superior acoustic performance.

porous composites, wave propagation, acoustical properties, homogenisation, pressure diffusion

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3. Frydrych K., Jarzębska A., Virupakshi S., Kowalczyk-Gajewska K., Bieda M., Chulist R., Skorupska M., Schell N., Sztwiernia K., Texture-based optimization of crystal plasticity parameters: application to zinc and its alloy, METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, ISSN: 1073-5623, DOI: 10.1007/s11661-021-06285-7, Vol.52, No.8, pp.3257-3273, 2021nota 7166

Evolutionary algorithms have become an extensively used tool for identification of crystal plasticity parameters of hexagonal close packed metals and alloys. However, the fitness functions were usually built using the experimentally measured stress–strain curves. Here, the fitness function is built by means of numerical comparison of the simulated and experimental textures. Namely, the normalized texture difference index is minimized. The evolutionary algorithm with the newly developed fitness function is tested by performing crystal plasticity parameter optimization for both pure zinc and zinc-magnesium alloy. These materials are promising candidates for bioabsorbable implants due to good biocompatibility and optimal corrosion rate. Although their mechanical properties in the as-cast state do not fulfill the requirements, they can be increased by means of hydrostatic extrusion. The developed modeling approach enabled acquisition of the crystal plasticity parameters and analysis of the active deformation mechanisms in zinc and zinc-magnesium alloy subjected to hydrostatic extrusion. It was shown that although slip systems are the main deformation carrier, compressive twinning plays an important role in texture evolution. However, the texture is also partially affected by dynamic recrystallization which is not considered within the developed framework.

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4. Krajewski M., Tokarczyk M., Lewińska S., Bochenek K., Ślawska-Waniewska A., Impact of thermal oxidation on morphological, structural and magnetic properties of Fe-Ni wire-like nanochains, METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, ISSN: 1073-5623, DOI: 10.1007/s11661-021-06326-1, Vol.52, No.8, pp.3530-3540, 2021nota 7181

This work presents the evolution of morphological, structural and magnetic properties of amorphous Fe-Ni wire-like nanochains caused by thermal oxidation. The initial Fe1−xNix samples (x = 0.75; 0.50; 0.25) were prepared through the magnetic-field-induced synthesis, and then they were heated in dry air at 400 °C and 500 °C. These treatments led to two competing simultaneous processes occurring in the investigated samples, i.e., (i) a conversion of amorphous material into crystalline material, and (ii) their oxidation. Both of them strictly affected the morphological and structural properties of the Fe-Ni nanochains which, in turn, were associated with the amount of iron in material. It was found that the Fe0.75Ni0.25 and Fe0.50Ni0.50 nanochains were covered during thermal treatment by the nanoparticle oxides. This coverage did not constitute a good barrier against oxidation, and these samples became more oxidized than the Fe0.25Ni0.75 sample which was covered by oxide nanosheets and contained additional Ni3B phase. The specific morphological evolutions of the Fe-Ni nanochains also influenced their saturation magnetizations, whereas their coercivities did not vary significantly. The obtained results constitute an important source of information for future application of the thermally treated Fe-Ni nanochains which could be applied in the energy storage devices or catalysis.

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5. Kowalczyk-Gajewska K., Majewski M., Mercier S., Molinari A., Mean field interaction model accounting for the spatial distribution of inclusions in elastic-viscoplastic composites, INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, ISSN: 0020-7683, DOI: 10.1016/j.ijsolstr.2021.111040, Vol.224, pp.111040-1-17, 2021nota 7121

A cluster interaction model has been proposed to account for the spatial distribution and morphology of particles when estimating the effective properties of elastic and thermoelastic composites (Molinari and El Mouden, 1996). In the present paper this approach is extended to elastic-viscoplastic composites. To this end the tangent linearization of the non-linear viscoplastic law and the concept of additive interaction equation are used. Although the extension is formulated for the non-linear case, first applications are considered for linear viscoelastic composites, a situation rich enough to evaluate the interest of the cluster interaction approach. Results of the model are compared to numerical homogenization for periodic
unit cells with two cubic configurations.

homogenization, the cluster interaction model, elastic-viscoplastic composite, spatial configuration of inclusions, interaction between inclusions

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6. Kopeć M., Brodecki A., Szczęsny G., Kowalewski Z.L., Microstructural analysis of fractured orthopedic implants, Materials, ISSN: 1996-1944, DOI: 10.3390/ma14092209, Vol.14, No.9, pp.2209-1-17, 2021nota 7122

In this paper, fracture behavior of four types of implants with different geometries (pure titanium locking plate, pure titanium femoral implant, Ti-6Al-4V titanium alloy pelvic implant, X2CrNiMo18 14-3 steel femoral implant) was studied in detail. Each implant fractured in the human body. The scanning electron microscopy (SEM) was used to determine the potential cause of implants fracture. It was found that the implants fracture mainly occurred in consequence of mechanical overloads resulting from repetitive, prohibited excessive limb loads or singular, un-intendent, secondary injures. Among many possible loading types, the implants were subjected to an excessive fatigue loads with additional interactions caused by screws that were mounted in their threaded holes. The results of this work enable to conclude that the design of orthopedic implants is not fully sufficient to transduce mechanical loads acting over them due to an increasing weight of treated patients and much higher their physical activity.

medical fixation devices, orthopedic prostheses and implants, titanium, titanium alloy, stainless steel, microscopic fracture analysis

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7. Tabin J., Skoczeń B., Bielski J., Discontinuous plastic flow in stainless steels subjected to combined loads at extremely low temperatures, INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES, ISSN: 0020-7403, DOI: 10.1016/j.ijmecsci.2021.106448, Vol.200, pp.106448-1-14, 2021nota 7124

In the present paper, the question of the mechanism of discontinuous plastic flow (DPF) occurring at extremely low temperatures (in the proximity of absolute zero), is for the first time raised in the context of kinematically controlled combined loads (independent control of displacement and rotation) and non-proportional loading paths. In order to identify the multiaxial stress state during DPF, a unique set-up for testing tubular samples under kinematically controlled traction and torsion in liquid helium (4.2 K) has been developed. The results of tests performed on grade 304 stainless steel thin-walled tubular samples subjected to combined loads (traction and torsion) in the proximity of absolute zero are for the first time reported. These novel results confirm the assumptions accepted when building the multiaxial constitutive model of discontinuous plastic flow, namely, the production of lattice barriers, the pile-ups of dislocations and the criterion of their collective failure, as well as the assumption that the serrations may be recorded by force and torque transducers independently. Thus, the numerically implemented model allows to reproduce the observed serrations, and to redistribute them between the loading directions.

plasticity, discontinuous plastic flow, cryogenic temperatures, combined loads, non-proportional loading paths

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8. Fantilli A.P., Jóźwiak-Niedźwiedzka D., Special issue: supplementary cementitious materials in concrete, part I, Materials, ISSN: 1996-1944, DOI: 10.3390/ma14092291, Vol.14, No.9, pp.2291-1-6, 2021pdf 7125
9. Zaremba D., Błoński S., Korczyk P.M., Integration of capillary–hydrodynamic logic circuitries for built-in control over multiple droplets in microfluidic networks, LAB ON A CHIP, ISSN: 1473-0197, DOI: 10.1039/D0LC00900H, Vol.21, No.9, pp.1771-1778, 2021nota 7126

Here, we show the successful implementation of advanced sequential logic in droplet microfluidics, whose principles rely on capillary wells establishing stationary states, where droplets can communicate remotely via pressure impulses, influencing each other and switching the device states. All logic operations perform spontaneously due to the utilization of nothing more than capillary–hydrodynamic interactions, inherent for the confined biphasic flow. Our approach offers integration feasibility allowing to encode unprecedentedly long algorithms, e.g., 1000-droplet counting. This work has the potential for the advancement of liquid computers and thereby could participate in the development of the next generation of portable microfluidic systems with embedded control, enabling applications from single-cell analysis and biochemical assays to materials science.

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10. Kaczmarek A., Denis P., Krajewski M., Mościcki T., Małolepszy A., Hoffman J., Improved laser ablation method for the production of luminescent carbon particles in liquids, Materials, ISSN: 1996-1944, DOI: 10.3390/ma14092365, Vol.14, No.9, pp.2365-1-17, 2021nota 7128

An improved method for the production of luminescent carbon nanoparticles is proposed in this work. The new method overcomes the disadvantages of commonly used approaches. It involves two-stage laser ablation in water and in aqueous solutions, where the first stage is the laser ablation of a graphite target and the second is the shredding of particles produced in the first step. The two-stage method offers the optimization of the laser pulse fluence for the performance of each process. It was found that the two-stage process of laser ablation allows producing photoluminescent carbon structures in pure water. The additional reagent may be added either in the first or second stage. The first stage performed in pure water allows avoiding the contamination of the target. Moreover, it simplifies the identification of the origin of photoluminescence. Two synthesis routes for the preparation of carbon nanoparticles by the proposed method using pure water as well as urea aqueous solution are investigated. It was found that the use of urea as a reagent results in luminescence properties similar to those obtained with other more hazardous amine-based reagents. The influence of the synthesis approach and process parameters on the structural and luminescent properties of nanoparticles is also explored in this work.

pulsed laser ablation in liquid, carbon nanoparticles, photoluminescent particles

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11. Postek E., Sadowski T., Impact model of the Al2O3/ZrO2 composite by peridynamics, COMPOSITE STRUCTURES, ISSN: 0263-8223, DOI: 10.1016/j.compstruct.2021.114071, Vol.271, pp.114071-1-12, 2021nota 7148

Ceramic composites (CCs) are mixtures of different phases, and their development is often regarded as a milestone in technological progress. They are used in practically all significant industries. Frequently, CCs are exposed to variable dynamic loads, impacts or high temperatures. In this paper, the impact of thin plates fabricated from Al2O3/ZrO2 is analyzed. The plates are made of the above CC with different proportions of its components. Damage progression is analyzed using peridynamics, similarly to quasi‐static tension. The purpose of the study is to describe the impact damage development in the CC plates and determine the role of phase contents. It has been found that phase ratios in the tested CC are vital for the behavior of the plates. In conclusion, it can be claimed that the employed peridynamic approach is suitable for solving the problems under study and that the impacting plates should be treated as real three‐dimensional structures.

Al2O3/ZrO2, brittle composite, peridynamics, impact loading

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12. Antolik A., Jóźwiak-Niedźwiedzka D., Assessment of the alkali-silica reactivity potential in granitic rocks, CONSTRUCTION AND BUILDING MATERIALS, ISSN: 0950-0618, DOI: 10.1016/j.conbuildmat.2021.123690, Vol.295, pp.123690-1-12, 2021nota 7151

The alkali-silica reactivity of granites may significantly affect the durability of road and airfield concrete pavements. The aim of the study was to evaluate the reactivity of granites commonly used as an aggregate in concrete pavements, with particular emphasis on microscopic methods. The research was focused on petrographic diagnosis of reactive minerals in granites, their quantitative analysis and comparison of the obtained results with standard measurements. The strained quartz was recognized as a reactive component and the linear relationship between its content and specimens expansion was found.

alkali-silica reaction, concrete, durability, granite, image analysis, microscopy, pavements, slow-reacting aggregates, expansion

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13. Zaszczyńska A., Moczulska-Heljak M., Gradys A., Sajkiewicz P., Advances in 3D printing for tissue engineering, Materials, ISSN: 1996-1944, DOI: 10.3390/ma14123149, Vol.14, No.12, pp.3149-1-28, 2021nota 7157

Tissue engineering (TE) scaffolds have enormous significance for the possibility of regeneration of complex tissue structures or even whole organs. Three-dimensional (3D) printing techniques allow fabricating TE scaffolds, having an extremely complex structure, in a repeatable and precise manner. Moreover, they enable the easy application of computer-assisted methods to TE scaffold design. The latest additive manufacturing techniques open up opportunities not otherwise available. This study aimed to summarize the state-of-art field of 3D printing techniques in applications for tissue engineering with a focus on the latest advancements. The following topics are discussed: systematics of the available 3D printing techniques applied for TE scaffold fabrication; overview of 3D printable biomaterials and advancements in 3D-printing-assisted tissue engineering.

tissue engineering, 3D printing, biomaterials

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14. Jenczyk P., Grzywacz H., Milczarek M., Jarząbek D.M., Mechanical and tribological properties of co-electrodeposited particulate-reinforced metal matrix composites: a critical review with interfacial aspects, Materials, ISSN: 1996-1944, DOI: 10.3390/ma14123181, Vol.14, No.12, pp.3181-1-36, 2021nota 7160

Particulate-reinforced metal matrix composites (PRMMCs) with excellent tribo-mechanical properties are important engineering materials and have attracted constant scientific interest over the years. Among the various fabrication methods used, co-electrodeposition (CED) is valued due to its efficiency, accuracy, and affordability. However, the way this easy-to-perform process is carried out is inconsistent, with researchers using different methods for volume fraction measurement and tribo-mechanical testing, as well as failing to carry out proper interface characterization. The main contribution of this work lies in its determination of the gaps in the tribo-mechanical research of CED PRMMCs. For mechanical properties, hardness is described with respect to measurement methods, models, and experiments concerning CED PRMMCs. The tribology of such composites is described, taking into account the reinforcement volume fraction, size, and composite fabrication route (direct/pulsed current). Interfacial aspects are discussed using experimental direct strength measurements. Each part includes a critical overview, and future prospects are anticipated. This review paper provides an overview of the tribo-mechanical parameters of Ni-based co-electrodeposited particulate-reinforced metal matrix composite coatings with an interfacial viewpoint and a focus on hardness, wear, and friction behavior.

experimental mechanics, tribology, co-electrodeposited composites

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15. Dulnik J., Sajkiewicz P., , Materials, ISSN: 1996-1944, DOI: 10.3390/ma14123391, Vol.14, No.12, pp.3391-1-13, 2021nota 7176

Four chemical crosslinking methods were used in order to prevent gelatin leaching in an aqueous environment, from bicomponent polycaprolactone/gelatin (PCL/Gt) nanofibers electrospun from an alternative solvent system. A range of different concentrations and reaction times were employed to compare genipin, 1-(3-dimethylaminopropyl)-N’-ethylcarbodimide hydrochloride/N-hydroxysuccinimide (EDC/NHS), 1,4-butanediol diglycidyl ether (BDDGE), and transglutaminase. The objective was to optimize and find the most effective method in terms of reaction time and solution concentration, that at the same time provides satisfactory gelatin crosslinking degree and ensures good morphology of the fibers, even after 24 h in aqueous medium in 37 °C. The series of experiments demonstrated that, out of the four compared crosslinking methods, EDC/NHS was able to yield satisfactory results with the lowest concentrations and the shortest reaction times.

crosslinking, gelatin, nanofibers, biodegradable polymers, electrospinning

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16. Steifer T., A note on the learning-theoretic characterizations of randomness and convergence, The Review of Symbolic Logic, ISSN: 1755-0203, DOI: 10.1017/S1755020321000125, pp.1-16, 2021nota 7183

Recently, a connection has been established between two branches of computability theory, namely between algorithmic randomness and algorithmic learning theory. Learning-theoretical characterizations of several notions of randomness were discovered. We study such characterizations based on the asymptotic density of positive answers. In particular, this note provides a new learning-theoretic definition of weak 2-randomness, solving the problem posed by (Zaffora Blando, Rev. Symb. Log. 2019). The note also highlights the close connection between these characterizations and the problem of convergence on random sequences.

algorithmic randomness, learning theory, effectivization

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17. Kukla D., Kopeć M., Wang K., Senderowski C., Kowalewski Z.L., Nondestructive methodology for identification of local discontinuities in aluminide layer-coated Mar 247 during its fatigue performance, Materials, ISSN: 1996-1944, DOI: 10.3390/ma14143824, Vol.14, No.14, pp.3824-1-13, 2021nota 7186

In this paper, the fatigue performance of the aluminide layer-coated and as-received MAR 247 nickel superalloy with three different initial microstructures (fine grain, coarse grain and column-structured grain) was monitored using nondestructive, eddy current methods. The aluminide layers of 20 and 40 µm were obtained through the chemical vapor deposition (CVD) process in the hydrogen protective atmosphere for 8 and 12 h at the temperature of 1040 °C and internal pressure of 150 mbar. A microstructure of MAR 247 nickel superalloy and the coating were characterized using light optical microscopy (LOM), scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS). It was found that fatigue performance was mainly driven by the initial microstructure of MAR 247 nickel superalloy and the thickness of the aluminide layer. Furthermore, the elaborated methodology allowed in situ eddy current measurements that enabled us to localize the area with potential crack initiation and its propagation during 60,000 loading cycles.

chemical vapor deposition, nickel alloys, aluminide coatings, fatigue, eddy current

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18. Rinoldi C., Lanzi M., Fiorelli R., Nakielski P., Zembrzycki K., Kowalewski T., Urbanek O., Grippo V., Jezierska-Woźniak K., Maksymowicz W., Camposeo A., Bilewicz R., Pisignano D., Sanai N., Pierini F., Three-dimensional printable conductive semi-interpenetrating polymer network hydrogel for neural tissue applications, BIOMACROMOLECULES, ISSN: 1525-7797, DOI: 10.1021/acs.biomac.1c00524, Vol.22, No.7, pp.3084-3098, 2021nota 7189

Intrinsically conducting polymers (ICPs) are widely used to fabricate biomaterials; their application in neural tissue engineering, however, is severely limited because of their hydrophobicity and insufficient mechanical properties. For these reasons, soft conductive polymer hydrogels (CPHs) are recently developed, resulting in a water-based system with tissue-like mechanical, biological, and electrical properties. The strategy of incorporating ICPs as a conductive component into CPHs is recently explored by synthesizing the hydrogel around ICP chains, thus forming a semi-interpenetrating polymer network (semi-IPN). In this work, a novel conductive semi-IPN hydrogel is designed and synthesized. The hybrid hydrogel is based on a poly(N-isopropylacrylamide-co-N-isopropylmethacrylamide) hydrogel where polythiophene is introduced as an ICP to provide the system with good electrical properties. The fabrication of the hybrid hydrogel in an aqueous medium is made possible by modifying and synthesizing the monomers of polythiophene to ensure water solubility. The morphological, chemical, thermal, electrical, electrochemical, and mechanical properties of semi-IPNs were fully investigated. Additionally, the biological response of neural progenitor cells and mesenchymal stem cells in contact with the conductive semi-IPN was evaluated in terms of neural differentiation and proliferation. Lastly, the potential of the hydrogel solution as a 3D printing ink was evaluated through the 3D laser printing method. The presented results revealed that the proposed 3D printable conductive semi-IPN system is a good candidate as a scaffold for neural tissue applications.

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19. Witecka A., Valet S., Basista M., Boccaccini A.R., Electrophoretically deposited high molecular weight chitosan/bioactive glass composite coatings on WE43 magnesium alloy, SURFACE AND COATINGS TECHNOLOGY, ISSN: 0257-8972, DOI: 10.1016/j.surfcoat.2021.127232, Vol.418, pp.127232-1-14, 2021nota 7127

Mg-based materials are good candidates for biodegradable bone regeneration implants due to their favorable mechanical properties and an excellent compatibility with human bone. However, too high corrosion/degradation rate in body fluids still limits their applicability. Coatings based on chitosan (CS) and bioactive glass (BG) particles fabricated by electrophoretic deposition (EPD) on Dulbecco's Modified Eagle Medium (DMEM) pre- treated magnesium alloys have promising potential to suppress the substrate corrosion and additionally to incorporate bioactivity. However, the impact of processing parameters or type of coating components on the long-term substrate corrosion behavior and cell response have not been investigated previously. In this study, two types of composite coatings based on a high molecular weight CS (Mw 340–360 kDa, DDA ≥95%) and embedded particles: solid BG (2 μm) and a mixture of BG and mesoporous bioactive glass nanoparticles (MBGN, 100–300 nm with mesopores 2.3–5.6 nm) were fabricated by EPD on DMEM pre-treated WE43 magnesium alloy. It was found that partial replacement of BG particles with MBGN (ratio 3:1) in the composite coating increases the water contact angle, surface roughness and induces a positive cell response. Although the acidic CS-based solutions and applied EPD conditions may decrease the stability of the temporary barrier formed during the DMEM pre-treatment on WE43 substrate therewith slightly increasing its corrosion sensitivity, the composite coating with a mixture of different sizes of particles (BG, MBGN) is a promising candidate for bone regeneration applications.

WE43, magnesium alloy, chitosan, bioactive glass, mesoporous nano bioactive glass, electrophoretic deposition

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20. Michalska M., Xu H., Shan Q., Zhang S., Dall'Agnese Y., Gao Y., Jain A., Krajewski M., Solution combustion synthesis of a nanometer-scale Co3O4 anode material for Li-ion batteries, Beilstein Journal of Nanotechnology, ISSN: 2190-4286, DOI: 10.3762/bjnano.12.34, Vol.12, pp.424-431, 2021nota 7130

A novel solution combustion synthesis of nanoscale spinel-structured Co3O4 powder was proposed in this work. The obtained material was composed of loosely arranged nanoparticles whose average diameter was about 36 nm. The as-prepared cobalt oxide powder was also tested as the anode material for Li-ion batteries and revealed specific capacities of 1060 and 533 mAh·g^−1 after 100 cycles at charge–discharge current densities of 100 and 500 mA·g^−1, respectively. Moreover, electrochemical measurements indicate that even though the synthesized nanomaterial possesses a low active surface area, it exhibits a relatively high specific capacity measured at 100 mA·g^−1 after 100 cycles and a quite good rate capability at current densities between 50 and 5000 mA·g^−1.

anode material, cobalt oxide, lithium-ion battery, solution combustion synthesis, transition metal oxide

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21. Urbanek O., Wysocka A., Nakielski P., Pierini F., Jagielska E., Sabała I., Staphylococcus aureus specific electrospun wound dressings: influence of immobilization technique on antibacterial efficiency of novel enzybiotic, Pharmaceutics, ISSN: 1999-4923, DOI: 10.3390/pharmaceutics13050711, Vol.13, No.5, pp.711-1-17, 2021nota 7132

The spread of antimicrobial resistance requires the development of novel strategies to combat superbugs. Bacteriolytic enzymes (enzybiotics) that selectively eliminate pathogenic bacteria, including resistant strains and biofilms, are attractive alternatives to antibiotics, also as a component of a new generation of antimicrobial wound dressings. AuresinePlus is a novel, engineered enzybiotic effective against Staphylococcus aureus—one of the most common pathogenic bacteria, found in infected wounds with a very high prevalence of antibiotic resistance. We took advantage of its potent lytic activity, selectivity, and safety to prepare a set of biodegradable PLGA/chitosan fibers generated by electrospinning. Our aim was to produce antimicrobial nonwovens to deliver enzybiotics directly to the infected wound and better control its release and activity. Three different methods of enzyme immobilization were tested: physical adsorption on the previously hydrolyzed surface, and covalent bonding formation using N-hydroxysuccinimide/N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide (NHS/EDC) or glutaraldehyde (GA). The supramolecular structure and functional properties analysis revealed that the selected methods resulted in significant development of nanofibers surface topography resulting in an efficient enzybiotic attachment. Both physically adsorbed and covalently bound enzymes (by NHS/EDC method) exhibited prominent antibacterial activity. Here, we present the extensive comparison between methods for the effective attachment of the enzybiotic to the electrospun nonwovens to generate biomaterials effective against antibiotic-resistant strains. Our intention was to present a comprehensive proof-of-concept study for future antimicrobial wound dressing development.

antibacterial wound dressings, enzybiotic, fibers functionalization, electrospun wound dressings, Staphylococcus aureus

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22. Lanzi M., Quadretti D., Marinelli M., Ziai Y., Salatelli E., Pierini F., Influence of the active layer structure on the photovoltaic performance of water-soluble polythiophene-based solar cells, Polymers, ISSN: 2073-4360, DOI: 10.3390/polym13101640, Vol.13, No.10, pp.1640-1-20, 2021nota 7133

A new side-chain C60-fullerene functionalized thiophene copolymer bearing tributylphosphine-substituted hexylic lateral groups was successfully synthesized by means of a fast and effective post-polymerization reaction on a regioregular ω-alkylbrominated polymeric precursor. The growth of the polymeric intermediate was followed by NMR spectrometry in order to determine the most convenient reaction time. The obtained copolymer was soluble in water and polar solvents and was used as a photoactive layer in single-material organic photovoltaic (OPV) solar cells. The copolymer photovoltaic efficiency was compared with that of an OPV cell containing a water-soluble polythiophenic homopolymer, functionalized with the same tributylphosphine-substituted hexylic side chains, in a blend with a water-soluble C60-fullerene derivative. The use of a water-soluble double-cable copolymer made it possible to enhance the 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. Indeed, the power conversion efficiency of OPV cells based on a single material was higher than that obtained with the classical architecture, involving the presence of two distinct ED and EA materials (PCE: 3.11% vs. 2.29%, respectively). Moreover, the synthetic procedure adopted to obtain single material-based cells is more straightforward and easier than that used for the preparation of the homopolymer-based BHJ solar cell, thus making it possible to completely avoid the long synthetic pathway which is required to prepare water-soluble fullerene derivatives.

water-soluble polymers, double-cable copolymers, polythiophenes, GRIM polymerization, tributylphosphine, water-soluble fullerenes, OPVs

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23. Wasyleczko M., Sikorska W., Przytulska M., Dulnik J., Chwojnowski A., Polyester membranes as 3D scaffolds for cell culture, Desalination and Water Treatment, ISSN: 1944-3994, DOI: 10.5004/dwt.2021.26658, Vol.214, pp.181-193, 2021nota 7143

The study presents two types of three-dimensional membranes made of the biodegradable copolymer. They were obtained by the wet-phase inversion method using different solvent and pore precursors. In one case, a nonwoven made of gelatin and polyvinylpyrrolidone (PVP) as precursors of macropores and small pores, respectively, were used. In the second case, PVP nonwovens and Pluronic were used properly for macro- and micro-pores. As the material, a biodegradable poly(L-lactide-co-ε-caprolactone) is composed of 30% ε-caprolactone and 70% poly(L-lactic acid) was used. Depending on the pore precursors, different membrane structures were obtained. The morphology of pores was studied using the MeMoExplorer™, an advanced software designed for computer analysis of the scanning electron microscopy images. The scaffolds were degraded in phosphate-buffered saline and Hank’s balanced salt solutions at 37°C. Moreover, the porosity of the membranes before and after hydrolysis was calculated.

3D scaffolds, poly(L-lactide-co-ε-caprolactone), porosity of membrane, phase inversion method, degradation of scaffolds

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24. Mikułowski G., Vibration isolation concept by switchable stiffness on a semi-active pneumatic actuator, SMART MATERIALS AND STRUCTURES, ISSN: 0964-1726, DOI: 10.1088/1361-665X/ac008f, Vol.30, No.7, pp.075019-1-15, 2021nota 7149

In this paper a novel technique of switchable stiffness dedicated to vibration isolation is presented. The approach utilises a semi-active pneumatic device in which the stiffness switching is obtained via controlled thermodynamic processes. The concept for the dissipation technique is introduced and a mathematical model is proposed. The system is analysed under passive and semi-active modes of operation by means of numerical simulation and in an experimental survey. The analysis consists of the model validation, an energy dissipation process study and a verification of effectiveness of the concept under varying operational conditions. As a result, it is demonstrated that the proposed technique allows for combining advantages of controllable pneumatic springs and pneumatic dampers, which constitutes an added value. It is revealed in the conducted tests that the system allows for 147% increase in energy dissipation per vibration cycle and reduce the resonant amplitude peak by 8%, both in comparison to a passive gas damper. The presented concept introduces an innovative approach to the switching stiffness techniques dedicated to vibration mitigation. The findings may significantly expand the number of their implementation possibilities.

semi-active, vibration isolation, pneumatic, experimental, piezoelectric, stiffness switch

no pdf 7149
25. Arafa A.A., Nada A.A., Ibrahim A.Y., Sajkiewicz P., Zahran M.K., Hakeim O.A., Preparation and characterization of smart therapeutic pH-sensitive wound dressing from red cabbage extract and chitosan hydrogel, International Journal of Biological Macromolecules, ISSN: 0141-8130, DOI: 10.1016/j.ijbiomac.2021.05.167, Vol.182, pp.1820-1831, 2021nota 7153

Developing a multifunctional wound dressing that protects, cures and indicates the healing progress, is a new approach of investigation. Red cabbage extract (RCE), consisting of bioactive compounds that have antioxidant, anti-inflammatory, anti-carcinogenic, bactericidal, antifungal, and antiviral activities, was utilized as a natural pH-sensitive indicator. Chitosan-based hydrogel, encapsulating RCE, was developed to obtain a smart therapeutic pH-sensitive wound dressing as antimicrobial bio-matrix provides a comfortable cushion for wound bed and indicates its status. Methacrylated-chitosan was crosslinked by different concentrations of methylenebisacrylamide (MBAA) by which hydrogel mechanical and morphological properties were tuned. The proposed mechanism for hydrogel formation was confirmed by FT-IR. The coloristic properties of the RCE and the changes in color intensity as a function of pH were confirmed by UV–Vis spectroscopy. The effect of MBAA on the mechanical, swelling, release and morphological properties of hydrogel were investigated. MBAA (2.5% wt/v) in 2% wt/v chitosan showed preferable mechanical (20 KPa), swelling (1294% at pH 8 ± 0.2), and release (prolonged up to 5 days) properties. Hydrogel matrices, loaded on cotton gauze submerged in different pH buffer solutions, showed explicit color changes from green to red as pH changed from 9 to 4.

pH-sensitive dye, wound dressing, N-methacylated chitosan

no pdf 7153
26. Sadowski P., Kowalczyk-Gajewska K., Stupkiewicz S., Spurious softening in the macroscopic response predicted by the additive tangent Mori–Tanaka scheme for elastic–viscoplastic composites, EUROPEAN JOURNAL OF MECHANICS A-SOLIDS, ISSN: 0997-7538, DOI: 10.1016/j.euromechsol.2021.104339, Vol.90, pp.104339-1-17, 2021nota 7159

The Mori–Tanaka (MT) scheme is a well-established mean-field model that combines simplicity and good predictive capabilities. The additive tangent MT scheme is a popular variant of the method that is suitable for elastic–viscoplastic composites. This work is concerned with the analysis of some intrinsic features of the additive tangent MT scheme, in particular, of spurious softening in the macroscopic response that may be encountered when the Perzyna-type viscoplasticity model is used. The resulting non-monotonic macroscopic stress–strain response is clearly non-physical, but it also has a negative impact on the efficiency and robustness of the MT model when it is used as a local constitutive model in concurrent multiscale finite-element computations. As shown in the paper, the spurious softening is more pronounced when the so-called soft isotropization is employed to compute the viscoplastic Hill tensor, but it is also observed, although for a much narrower range of material parameters, in the case of the hard isotropization and when no isotropization is applied. Moreover, the softening is promoted at low strain rates, for high elastic contrast, and for high volume fractions of inclusions. Nevertheless, if the soft isotropization is avoided, the additive tangent MT scheme proves to be a feasible and computationally robust mean-field model that can be successfully employed in finite-element computations.

mean-field homogenization, Mori–Tanaka method, isotropization, composite materials, viscoplasticity

pdf 7159
27. Kaźmierczak B., Sneyd J., Speed of traveling waves for monotone reaction–diffusion systems as a function of diffusion coefficients, PHYSICA D-NONLINEAR PHENOMENA, ISSN: 0167-2789, DOI: 10.1016/j.physd.2021.132940, Vol.424, pp.132940-1-23, 2021nota 7163

Traveling waves form a basic class of solutions to reaction–diffusion equations, which can describe a large number of phenomena. The basic property characterizing traveling wave solutions is their speed of propagation. In this study we analyze its dependence on the diffusivities of the interacting agents. We show that this dependence is subject to some relations, which can be derived by simple scaling properties. We augment our findings by an investigation of reaction–diffusion systems describing intercellular calcium dynamics in the presence of buffer molecules. We establish some mathematical results concerning the behavior of the velocity of traveling waves in the case of fast buffer kinetics, (paying special attention to the vicinity of zero speed), and present outcomes of numerical simulations showing how complicated the interplay between the diffusion coefficients of calcium and buffering molecules can be, especially in models with more than one kind of buffer molecules.

reaction-diffusion equations, traveling waves, Euler’s homogeneous function theorem, buffered calcium systems

no pdf 7163
28. Núñez G., Venegas R., Zieliński T.G., Bécot F.-X., Equivalent fluid approach to modeling the acoustical properties of polydisperse heterogeneous porous composites, PHYSICS OF FLUIDS, ISSN: 1070-6631, DOI: 10.1063/5.0054009, Vol.33, No.6, pp.062008-1-19, 2021nota 7167

This paper investigates sound propagation in polydisperse heterogeneous porous composites. The two-scale asymptotic method of homogenization is used to obtain a macroscopic description of the propagation of sound in such composites. The upscaled equations demonstrate that the studied composites can be modeled as equivalent fluids with complex-valued frequency-dependent effective parameters (i.e., dynamic viscous permeability and compressibility) as well as unravel the sound energy dissipation mechanisms involved. The upscaled theory is both exemplified by introducing analytical and hybrid models for the acoustical properties of porous composites with different geometries and constituent materials (e.g., a porous matrix with much less permeable and/or impervious inclusions with simple or complex shapes) and validated through computational experiments successfully. It is concluded that the developed theory rigorously captures the physics of acoustic wave propagation in polydisperse heterogeneous porous composites and shows that the mechanisms that contribute to the dissipation of sound energy in the composite are classical visco-thermal dissipation together with multiple pressure diffusion phenomena in the heterogeneous inclusions. The results show that the combination of two or more permeable materials with highly contrasted permeabilities
can improve the acoustic absorption and transmission loss of the composite. This paper provides fundamental insights into the propagation of acoustic waves in complex composites that are expected to guide the rational design of novel acoustic materials.

no pdf 7167
29. Gabriele V.R., Mazhabi R.M., Alexander N., Mukherjee P., Seyfried T.N., Nwaji N., Akinoglu E.M., Mackiewicz A., Zhou G., Giersig M., Naughton M.J., Kempa K., Light- and melanin nanoparticle-induced cytotoxicity in metastatic cancer cells, Pharmaceutics, ISSN: 1999-4923, DOI: 10.3390/pharmaceutics13070965, Vol.13, No.7, pp.965-1-14, 2021nota 7177

Melanin nanoparticles are known to be biologically benign to human cells for a wide range of concentrations in a high glucose culture nutrition. Here, we show cytotoxic behavior at high nanoparticle and low glucose concentrations, as well as at low nanoparticle concentration under exposure to (nonionizing) visible radiation. To study these effects in detail, we developed highly monodispersed melanin nanoparticles (both uncoated and glucose-coated). In order to study the effect of significant cellular uptake of these nanoparticles, we employed three cancer cell lines: VM-M3, A375 (derived from melanoma), and HeLa, all known to exhibit strong macrophagic character, i.e., strong nanoparticle uptake through phagocytic ingestion. Our main observations are: (i) metastatic VM-M3 cancer cells massively ingest melanin nanoparticles (mNPs); (ii) the observed ingestion is enhanced by coating mNPs with glucose; (iii) after a certain level of mNP ingestion, the metastatic cancer cells studied here are observed to die—glucose coating appears to slow that process; (iv) cells that accumulate mNPs are much more susceptible to killing by laser illumination than cells that do not accumulate mNPs; and (v) non-metastatic VM-NM1 cancer cells also studied in this work do not ingest the mNPs, and remain unaffected after receiving identical optical energy levels and doses. Results of this study could lead to the development of a therapy for control of metastatic stages of cancer.

melanoma, melanin nanoparticles, cytotoxicity, laser medical applications, hyperthermia

pdf 7177
30. Gambin B., Kruglenko E., Ultrasonic specific absorption rate in nanoparticle-mediated moderate hyperthermia, BULLETIN OF THE POLISH ACADEMY OF SCIENCES: TECHNICAL SCIENCES, ISSN: 2300-1917, DOI: 10.24425/bpasts.2021.137053, Vol.69, No.3, pp.e137053-1-18, 2021nota 7178

Magnetic nanoparticle’s different applications in nanomedicine, due to their unique physical properties and biocompatibility, were intensively investigated. Recently, Fe3O4 nanoparticles, are confirmed to be the best sonosensitizers to enhance the performance of HIFU (high intensity focused ultrasound). They are also used as thermo-sensitizers in magnetic hyperthermia. A new idea of dual, magneto-ultrasound, coupled hyperthermia allows the ultrasound intensity to be reduced from the high to a moderate level. Our goal is to evaluate the enhancement of thermal effects of focused ultrasound of moderate intensity due to the presence of nanoparticles. We combine experimental results with numerical analysis. Experiments are performed on tissue-mimicking materials made of the 5% agar gel and gel samples containing Fe3O4 nanoparticles with φ = 100 nm with two fractions of 0.76 and 1.53% w/w. Thermocouples registered curves of temperature rising during heating by focused ultrasound transducer with acoustic powers of the range from 1 to 4 W. The theoretical model of ultrasound-thermal coupling is solved in COMSOL Multiphysics. We compared the changes between the specific absorption rates (SAR) coefficients determined from the experimental and numerical temperature rise curves depending on the nanoparticle fractions and applied acoustic powers.We confirmed that the significant role of nanoparticles in enhancing the thermal effect is qualitatively similarly estimated, based on experimental and numerical results. So that we demonstrated the usefulness of the FEM linear acoustic model in the planning of efficiency of nanoparticle-mediated moderate hyperthermia.

ultrasonic hyperthermia, agar-based tissue mimicking phantom, magnetic nanoparticles, temperature, specific absorption rate (SAR)

pdf 7178
31. Postek E., Nowak Z., Pęcherski R.B., Viscoplastic flow of functional cellular materials with use of peridynamics, MECCANICA, ISSN: 0025-6455, DOI: 10.1007/s11012-021-01383-7, pp.1-18, 2021nota 7182

The subject of the study is the deformation of the oxygen-free high conductivity copper. The copper sample is given in the form of a foam. The sample undergoes an impact into an elastic wall. The strain rate hardening effect is investigated. The numerical model of the open-cell foam skeleton is prepared in the framework of the peridynamics method. The dynamic process of compression with different impact velocities is simulated. It has been found that the strain rate hardening effect is essential for the load-carrying capacity of the material under study. Taylor impact test of solid cylinder analysis precedes the analysis of the metallic foam.

cellular materials, OFHC copper, elastic-viscoplastic model, strain rate hardening, peridynamics, foam skeleton

pdf 7182
32. Badora M., Sepe M., Bielecki M., Graziano A., Szolc T., Predicting length of fatigue cracks by means of machine learningalgorithms in the small-data regime, EKSPLOATACJA I NIEZAWODNOŚĆ - MAINTENANCE AND RELIABILITY, ISSN: 1507-2711, DOI: 10.17531/ein.2021.3.19, Vol.23, No.3, pp.575-585, 2021nota 7188

In this paper several statistical learning algorithms are used to predict the maximal length of fatigue cracks based on a sample composed of 31 observations. The small-data regime is still a problem for many professionals, especially in the areas where failures occur rarely. The analyzed object is a high-pressure Nozzle of a heavy-duty gas turbine. Operating parameters of the engines are used for the regression analysis. The following algorithms are used in this work: multiple linear and polynomial regression, random forest, kernel-based methods, AdaBoost and extreme gradient boosting and artificial neural networks. A substantial part of the paper provides advice on the effective selection of features. The paper explains how to process the dataset in order to reduce uncertainty; thus, simplifying the analysis of the results. The proposed loss and cost functions are custom and promote solutions accurately predicting the longest cracks. The obtained results confirm that some of the algorithms can accurately predict maximal lengths of the fatigue cracks, even if the sample is small.

empirical models, fatigue cracks, predictive maintenance, regression analysis, small data, statistical learning, turbomachinery

no pdf 7188
33. Piechocka I.K., Keary S., Sosa-Costa A., Lau L., Mohan N., Stanisavljevic J., Borgman K.J.E., Lakadamyali M., Manzo C., Garcia-Parajo M.F., Shear forces induce ICAM-1 nanoclustering on endothelial cells that impact on T-cell migration, BIOPHYSICAL JOURNAL, ISSN: 0006-3495, DOI: 10.1016/j.bpj.2021.05.016, Vol.120, No.13, pp.2644-2656, 2021nota 7190

The leukocyte-specific β2-integrin LFA-1 and its ligand ICAM-1, expressed on endothelial cells (ECs), are involved in the arrest, adhesion, and transendothelial migration of leukocytes. Although the role of mechanical forces on LFA-1 activation is well established, the impact of forces on its major ligand ICAM-1 has received less attention. Using a parallel-plate flow chamber combined with confocal and super-resolution microscopy, we show that prolonged shear flow induces global translocation of ICAM-1 on ECs upstream of flow direction. Interestingly, shear forces caused actin rearrangements and promoted actin-dependent ICAM-1 nanoclustering before LFA-1 engagement. T cells adhered to mechanically prestimulated ECs or nanoclustered ICAM-1 substrates developed a promigratory phenotype, migrated faster, and exhibited shorter-lived interactions with ECs than when adhered to non mechanically stimulated ECs or to monomeric ICAM-1 substrates. Together, our results indicate that shear forces increase ICAM-1/LFA-1 bonds because of ICAM-1 nanoclustering, strengthening adhesion and allowing cells to exert higher traction forces required for faster migration. Our data also underscore the importance of mechanical forces regulating the nanoscale organization of membrane receptors and their contribution to cell adhesion regulation.

no pdf 7190
34. Dąbrowski M., Glinicki M.A., Dziedzic K., Jóźwiak-Niedźwiedzka D., Sikorin S., Fateev V.S., Povalansky E.I., Early age hardening of concrete with heavy aggregate in gamma radiation source – impact on the modulus of elasticity and microstructural features, Journal of Advanced Concrete Technology, ISSN: 1346-8014, DOI: 10.3151/jact.19.555, Vol.19, No.5, pp.555-570, 2021nota 7150

The effects of gamma irradiation on concrete properties during early hardening were studied towards radioactive waste storage or accelerated processing at precast plants. Concrete mixtures containing different mineral aggregates (baryte, magnetite, amphibolite) were investigated. During initial 16 hours of hardening the mixes were irradiated using 60Co gamma source at the rate of 3.5 kGy/h. The mechanical properties and microstructural features of irradiated early-age concrete were tested: the secant elastic modulus, the compressive strength, the porosity and pore size distribution. XRD and SEM analysis were also performed. The results indicate both the stiffening and pore refinement in concrete due to early gamma irradiation. Effects of early irradiation on microstructural features of cement matrix were found in the subsurface layer up to the depth of 2 mm. The influence of different mineral aggregates in concrete on the radiation-induced changes of early age properties is discussed.

no pdf 7150
35. Gupta A., Jain A., Tripathi S., Structural, electrical and electrochemical studies of ionic liquid-based polymer gel electrolyte using magnesium salt for supercapacitor application, Journal of Polymer Research, ISSN: 1572-8935, DOI: 10.1007/s10965-021-02597-9, Vol.28, pp.235-1-11, 2021nota 7155

In the present studies, the effect of ionic liquid 1-Ethyl-2,3-dimethylimidazoliumtetrafluoroborate (EDiMIM)(BF4) on ionic conductivity of gel polymer electrolyte using poly(vinylidene fluoride-co-hexafluoropropylene) [PVdF(HFP)] and magnesium perchlorate [Mg(ClO4)2] as salt was investigated. The maximum room temperature ionic conductivity for the optimized system was found to be of the order of 8.4 × 10^–3 S cm^−1. The optimized composition reflects Vogel-Tammann-Fulcher (VTF) behavior in the temperature range of 25 °C to 100 °C. The X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy studies confirm the uniform blending of ionic liquid, polymer, and salts along with the enhanced amorphous nature of the optimized system. Dielectric and modulus spectra studies provide the information of electrode polarization as well as dipole relaxation properties of polymeric materials. The optimized electrolyte system possesses a sufficiently large electrochemical window of the order of 6.0 V with stainless steel electrodes.

gel polymer electrolyte, ionic liquid, ionic conductivity, temperature dependence, supercapacitors

no pdf 7155
36. Wrzecionek M., Bandzerewicz A., Dutkowska E., Dulnik J., Denis P., Gadomska-Gajadhur A., Poly(glycerol citrate)-polylactide nonwovens toward tissue engineering applications, Polymers for Advanced Technologies, ISSN: 1042-7147, DOI: 10.1002/pat.5407, pp.1-12, 2021nota 7156

In 2002, Robert Langer proposed that new polyester for tissue engineering should have good mechanical properties followed by: covalent bonding (as crosslinking) and hydrogen-bonding interactions; and should be elastic like rubber materials due to three-dimensional network structure. Considering these hypotheses, a polyester made of glycerol and citric acid was designed in this work. Poly(glycerol citrate) should be attractive for tissue engineering because both glycerol and citric acid, taking part in natural human metabolic pathways; and due to the reactant's functionality, 3D networks should be produced easily. Moreover, the reagents are cheap, available, and often used in the food and pharmaceutical industries. In this work, poly(glycerol citrate) was synthesized and then used with PLA for creating porous nonwovens by electrospinning. Produced materials were tested for possible application in the field of tissue engineering. The obtained materials have properties similar to collagen fibers, but still, require refinement for medical applications.

electrospinning, poly(glycerol citrate), polylactide, tissue engineering

no pdf 7156
37. Fura Ł., Dera W., Dziekoński C., Świątkiewicz M., Kujawska T., Experimental assessment of the impact of sonication parameters on necrotic lesions induced in tissues by HIFU ablative device for preclinical studies, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.24425/aoa.2021.136573, Vol.46, No.2, pp.341-352, 2021nota 7158

We have designed and built ultrasound imaging-guided HIFU ablative device for preclinical studies on small animals. Before this device is used to treat animals, ex vivo tissue studies were necessary to determine the location and extent of necrotic lesions created inside tissue samples by HIFU beams depending on their acoustic properties. This will allow to plan the beam movement trajectory and the distance and time intervals between exposures leading to necrosis covering the entire treated volume without damaging the surrounding tissues. This is crucial for therapy safety. The objective of this study was to assess the impact of sonication parameters on the size of necrotic lesions formed by HIFU beams generated by 64-mm bowl-shaped transducer used, operating at 1.08 MHz or 3.21 MHz. Multiple necrotic lesions were created in pork loin samples at 12.6-mm depth below tissue surface during 3-s exposure to HIFU beams with fixed duty-cycle and varied pulse-duration or fixed pulse-duration and varied duty-cycle, propagated in two-layer media: water-tissue. After exposures, the necrotic lesions were visualized using magnetic resonance imaging and optical imaging (photos) after sectioning the samples. Quantitative analysis of the obtained results allowed to select the optimal sonication and beam movement parameters to suport planning of effective therapy.

automated ultrasound imaging-guided HIFU ablation system, ex vivo tissue, ultrasonic exposure parameters, extent of necrotic lesions

pdf 7158
38. Ignaczak J., Stress characterization of elastodynamics for a rotating cylinder, Mathematics and Mechanics of Complex Systems, ISSN: 2325-3444, DOI: 10.2140/memocs.2021.9.143, Vol.9, No.2, pp.143-151, 2021nota 7131

In the present paper, the stress characterization of elastodynamics for a rotating inhomogeneous transversely isotropic cylinder under plane strain conditions is proposed. It is assumed that the geometrical axis of the cylinder coincides with the axis of rotational symmetry of the cylinder. The cylinder rotates together with the Cartesian coordinate system xi (i=1,2,3), in which the geometrical axis of the cylinder coincides with the x3-axis, with a uniform angular velocity Ω in such a way that the acceleration of the cylinder is a sum of three components: (i) classical acceleration, (ii) centripetal acceleration, and (iii) Coriolis acceleration. It is shown that the propagation of an elastic wave in the 3D rotating cylinder can be described by a solution to the associated 2D pure stress initial-boundary value problem. Such a reduction of the 3D problem to the 2D one is based on the theorem on an alternative representation of the displacement vector field u in terms of the stress field S. An example of a complete pure stress formulation of the traction initial-boundary value problem is presented.

stress language of elastodynamics, rotating cylinder, classical acceleration, centripetal acceleration, Coriolis acceleration, transversely isotropic inhomogeneous elastic materials, completeness of stress formulation, natural stress traction initial-boundary value problem

no pdf 7131
39. Zhang Q., Hou J., Duan Z., Jankowski Ł., Hu X., Road roughness estimation based on the vehicle frequency response function, Actuators, ISSN: 2076-0825, DOI: 10.3390/act10050089, Vol.10, No.5, pp.89-1-20, 2021nota 7123

Road roughness is an important factor in road network maintenance and ride quality. This paper proposes a road-roughness estimation method using the frequency response function (FRF) of a vehicle. First, based on the motion equation of the vehicle and the time shift property of the Fourier transform, the vehicle FRF with respect to the displacements of vehicle–road contact points, which describes the relationship between the measured response and road roughness, is deduced and simplified. The key to road roughness estimation is the vehicle FRF, which can be estimated directly using the measured response and the designed shape of the road based on the least-squares method. To eliminate the singular data in the estimated FRF, the shape function method was employed to improve the local curve of the FRF. Moreover, the road roughness can be estimated online by combining the estimated roughness in the overlapping time periods. Finally, a half-car model was used to numerically validate the proposed methods of road roughness estimation. Driving tests of a vehicle passing over a known-sized hump were designed to estimate the vehicle FRF, and the simulated vehicle accelerations were taken as the measured responses considering a 5% Gaussian white noise. Based on the directly estimated vehicle FRF and updated FRF, the road roughness estimation, which considers the influence of the sensors and quantity of measured data at different vehicle speeds, is discussed and compared. The results show that road roughness can be estimated using the proposed method with acceptable accuracy and robustness.

structural health monitoring, road roughness, vehicle response, frequency response function, Fourier transform

pdf 7123
40. Morbidi F., Pisarski D., Practical and accurate generation of energy-optimal trajectories for a planar quadrotor, ICRA 202, 2021 IEEE International Conference on Robotics and Automation, 2021-05-30/06-05, Xi'an (CN), pp.1-7, 2021nota 7192

Motivated by the limited flight time of battery-powered multi-rotor UAVs, in this paper we address the problem of generating energy-optimal trajectories for a planar quadrotor. More specifically, by considering an accurate electrical model for the brushless DC motors and rest-to-rest maneuvers between two predefined boundary states, we explicitly compute the minimum-energy curves by adopting a free and a fixed end-time optimal control formulation. The numerical solution of these optimal control problems hinges upon a simple yet effective indirect projected gradient method. Simulation experiments illustrate the theory in a variety of realistic flight scenarios.

pdf 7192
41. Kaczmarek A., Hoffman J., Okołowicz A., Małolepszy A., Photoluminescence properties of carbon nanoparticles synthesized by laser ablation in water and aqueous solutions of amine-based reagents, EYEC-9, European Young Engineers Conference, 2021-04-19/04-21, Warszawa (PL), pp.12.7-172, 2021nota 7129

pulsed laser ablation in liquids, carbon nanoparticles, optical properties

pdf 7129
42. Kopeć M., Brodecki A., Kowalewski Z.L., Microstructural analysis of fractured orthopedic implants, XXII Polish Conference on Biocybernetics and Biomedical Engineering, 2021-05-19/05-21, Warszawa (PL), pp.1, 2021pdf 7135
43. Dubey V.P., Kopeć M., Kowalewski Z.L., Insight of magnesium matrix nanocomposites for biomedical applications - a synthetic review, XXII Polish Conference on Biocybernetics and Biomedical Engineering, 2021-05-19/05-21, Warszawa (PL), pp.1, 2021pdf 7136
44. Fura Ł., Żołek N., Kujawska T., Numerical simulations of the ultrasonic tissue ablation process, XXII Polish Conference on Biocybernetics and Biomedical Engineering, 2021-05-19/05-21, Warszawa (PL), pp.1, 2021pdf 7137
45. Zaszczyńska A., Sajkiewicz P.Ł., Designing three-dimensional piezoelectric scaffolds for neural tissue engineering, XXII Polish Conference on Biocybernetics and Biomedical Engineering, 2021-05-19/05-21, Warszawa (PL), pp.152, 2021pdf 7138
46. Niemczyk-Soczyńska B., Sajkiewicz P., Thermosensitive hydrogel/short electrospun fibers as a smart scaffold for tissue engineering, XXII Polish Conference on Biocybernetics and Biomedical Engineering, 2021-05-19/05-21, Warszawa (PL), pp.97, 2021pdf 7139
47. Opiela K.C., Zieliński T.G., Attenborough K., Impedance-tube characterisation of additively manufactured slitted sound absorbers, SAPEM’2020+1, 6th (Triennial) Symposium on the Acoustics of Poro-Elastic Materials, 2021-03-29/04-02, Purdue University, West Lafayette, Indiana (US), pp.1-2, 2021nota 7140

An acoustical characterisation of additively manufactured rigid slitted structures is considered. A set of six JCAL microstructural parameters is deduced from dynamic density and bulk modulus obtained from normal incidence surface acoustic impedance experimental data. The results show that the characteristic lengths are the most difficult to characterise.

pdf 7140
48. Postek E., Sadowski T., Boniecki M., Impact of brittle composites: peridynamics modelling, Materials Today: Proceedings, ISSN: 2214-7853, DOI: 10.1016/j.matpr.2020.12.511, Vol.45, pp.4268-4274, 2021nota 7142

Ceramic composites are used in such industries as the armaments industry, aviation, automotive, nuclear power, and space exploration. In several areas, they stand as the source of technological progress. The material is often subjected to extreme loads, such as variable dynamic loads and high temperatures. Peridynamics is a non-local, meshless, quite recently formulated method of stress analysis. The methods appear to be useful in the analysis of brittle materials. In the paper, an impact model of an Al2O3/ZrO2 thin plate is investigated. A brittle damage model is used for both phases of the composite. The attention is focused on damage initiation and distribution in the impacting sample.

brittle composites, Al2O3/ZrO2, impact, peridynamics

no pdf 7142
49. Barwińska I., Durejko T., Kopeć M., Kowalewski Z.L., Ocena możliwości regeneracji części maszyn i urządzeń z wykorzystaniem systemów LENS, Międzynarodowa Studencka Sesja Naukowa Materiały i Technologie XXI wieku, 2021-05-28/05-28, Gliwice (PL), pp.1, 2021pdf 7144
50. Kopeć M., Brodecki A., Kowalewski Z.L., Fraktograficzna analiza pęknięć implantów ortopedycznych, Międzynarodowa Studencka Sesja Naukowa Materiały i Technologie XXI wieku, 2021-05-28/05-28, Gliwice (PL), pp.1, 2021pdf 7145
51. Dubey V.P., Kopeć M., Mallick A., Kowalewski Z.L., An effect of enhanced solid solubility on the microstructure and mechanical properties of Al-Cr solid solution by powder metallurgy process, Międzynarodowa Studencka Sesja Naukowa Materiały i Technologie XXI wieku, 2021-05-28/05-28, Gliwice (PL), pp.1, 2021pdf 7146
52. Kopeć M., A highly efficient 'FAST' hot stamping process for complex shaped panel components from titanium alloys, 7th „Young Researchers’ Innovative Ideas: Science – Start-Ups – Industry”, 2021-05-27/05-28, Kraków (PL), pp.1, 2021pdf 7147
53. Opiela K.C., Zieliński T.G., Predicting sound absorption in additively manufactured porous materials using multiscale simulations in FEniCS, FEniCS 2021 Conference, 2021-03-22/03-26, Cambridge (GB), DOI: 10.6084/m9.figshare.14495349, pp.370, 2021nota 7152

sound absorption, porous material, multiscale modelling, coupled problem

pdf 7152
54. Kopeć M., Wang K., Yuan X., Wang L., Kowalewski Z.L., A novel fast light alloys stamping technology (FAST) for complex titanium alloy components, 5th National Scientific Conference Science and Young Researchers, 2021-06-05/06-05, Łódź (PL), pp.1, 2021pdf 7154
55. Kaczmarek A., Hoffman J., Denis P., Mościcki T., Photoluminescence of carbon nanoparticles synthesized by laser ablation in water and aqueous solutions of amine-based reagents, 2nd Advanced Materials Science World Congress 2021, 2021-06-14/06-15, Berlin (DE), pp.60, 2021pdf 7161
56. Psiuk R., Jarząbek D., Denis P., Mościcki T., W-Zr-B coatings deposited by RF Magnetron – PLD hybrid method, 2nd Advanced Materials Science World Congress 2021, 2021-06-14/06-15, Berlin (DE), pp.59, 2021pdf 7162
57. Kopeć M., Dubey V.P., Brodecki A., Kowalewski Z.L., Failure analysis of orthopedic implants, IMPLANTY'2021, III Ogólnopolska Konferencja Naukowa IMPLANTY2021 Koncepcja a realia we współczesnych rozwiązaniach, 2021-06-18/06-18, Gdańsk (PL), pp.1, 2021nota 7173

medical fixation devices, orthopedicimplants, SEM, fracture analysis, titanium alloy, stainless steel

pdf 7173
58. Fantilli A.P., Jóźwiak-Niedźwiedzka D., Sheep wool as fiber-reinforcement of gypsum composites, ICBBM'2021, 4th International Conference on Bio-Based Building Materials, 2021-06-16/06-18, Barcelona (ES), pp.108-111, 2021nota 7175

Depending on the intended use, some cement-based construction materials, such as paste, mortar and concrete, need to be fibre reinforced. In these materials, fibres play the same mechanical role as ossein, the elastic collagen fibres in animal bones that guarantees the resistance to fracture. Although commonly used fibres are made of various materials, such as steel, glass, polymers etc., animal and plant fibres can also be used in building materials. Among them, wool of sheep, a waste material in several countries, can effectively reinforce pastes, mortars and concretes. In addition to the research already performed in the field of cement-based composites, the use of sheep wool as reinforcement of gypsum-based composite is experimentally investigated herein for the first time. As a result, sheep wool reinforcement provides high fracture toughness, due to an excellent adhesion, and could be a valid alternative to the current industrial fibres in reinforced gypsum manufacts.

sheep wool fibres, gypsum-based composite, mechanical properties, microstructure

pdf 7175
59. Gambin B., Kruglenko E., Melnikova P., Tymkiewicz R., Strzałkowski R., Krajewski M., Impact of the ferrogel fine structure on magnetic heating efficiency, PM'21, The European Conference Physics of Magnetism 2021, 2021-06-28/07-02, Poznań (PL), pp.1, 2021pdf 7179
60. Gambin B., Miklewska A., Kruglenko E., Comparison of the influence of superparamagnetic nanoparticles concentration and coverage on the alternating magnetic field thermal effect, PM'21, The European Conference Physics of Magnetism 2021, 2021-06-28/07-02, Poznań (PL), pp.1, 2021pdf 7180
61. Sadowski T., Postek E., Pietras D., Boniecki M., Szutkowska M., Description of quasi-static and dynamic damage processes in 2-phase ceramic matrix and metal matrix composites reinforced by ceramic grains, ACE-X 2021, 14th INTERNATIONAL CONFERENCE ON ADVANCED COMPUTATIONAL ENGINEERING AND EXPERIMENTING - ACE-X 2021, 2021-07-04/07-08, St. Julian's (MT), pp.9-10, 2021nota 7184

Quasi-static degradation of brittle composites exhibits different mechanical responses under uniaxial tension and uniaxial compression. In this paper, we analysed cracking processes and failure under quasi-static loading of 2 phase ceramic material made of alumina and zirconia mixture, subjected to tension and compression. Constitutive modelling of two-phase ceramic composites obeys description of (1) elastic deformations of initially porous material, (2) limited plasticity and (3) cracks initiation and propagation. Modelling of polycrystalline ceramics at the mesoscopic level under mechanical loading is related to the analysis of a set of grains, which create a so-called Representative Volume Element (RVE). The basic elements of the defect structure inside polycrystal are: micro- and meso-cracks, kinked and wing cracks. To get the macroscopic response of the material one can calculate averaged values of stress and strain over the RSE with the application of an analytical approach. The dynamic degradation process was illustrated for 2 phase ceramic matrix composite and cermet, which was subjected to short compressive impulse. The pulse duration was 10-7s and the applied pressure level - 480 MPa. In the proposed, more advanced finite element formulation of the cermet behaviour is was necessary to take into account the following data and phenomena revealing inside of the RVE: (1) spatial distribution of the cermet constituents, (2) system of grain boundaries/binder interfaces modelled by interface elements, (3) rotation of brittle grains. The cermet response due to pulse loading is significantly different in comparison to the quasi-static behaviour, i.e. the stress distributions and microcracking processes are quite different.

cermets, dynamic behaviour, brittle cracking

pdf 7184
62. Steifer T., Simple betting and stochasticity, CiE 2021, Connecting with Computability, 2021-07-05/07-09, Ghent (BE), DOI: 10.1007/978-3-030-80049-9_42, No.12813, pp.424-433, 2021nota 7185

A sequence of zeros and ones is called Church stochastic if all subsequences chosen in an effective manner satisfy the law of large numbers with respect to the uniform measure. This notion may be independently defined by means of simple martingales, i.e., martingales with restricted (constant) wagers (hence, simply random sequences). This paper is concerned with generalization of Church stochasticity for arbitrary (possibly non-stationary) measures. We compare two ways of doing this: (i) via a natural extension of the law of large numbers (for non-i.i.d. processes) and (ii) via restricted martingales, i.e., by redefining simple randomness for arbitrary measures. It is shown that in the general case of non-uniform measures the respective notions of stochasticity do not coincide but the first one is contained in the second.

no pdf 7185
63. Guglielmelli A., Pierini F., Tabiryan N., Umeton C., Bunning T.J., De Sio L., Thermoplasmonics with gold nanoparticles: a new weapon in modern optics and biomedicine, Advanced Photonics Research, ISSN: 2699-9293, DOI: 10.1002/adpr.202000198, pp.2000198-1-17, 2021nota 7191

Thermoplasmonics deals with the generation and manipulation of nanoscale heating associated with noble metallic nanoparticles. To this end, gold nanoparticles (AuNPs) are unique nanomaterials with the intrinsic capability to generate a nanoscale confined light-triggered thermal effect. This phenomenon is produced under the excitation of a suitable light of a wavelength that matches the localized surface plasmonic resonance frequency of AuNPs. Liquid crystals (LCs) and hydrogels are temperature-sensitive materials that can detect the host AuNPs and their photo-induced temperature variations. In this perspective, new insight into thermoplasmonics, by describing a series of methodologies for monitoring, detecting, and exploiting the photothermal properties of AuNPs, is offered. From conventional infrared thermography to highly sophisticated temperature-sensitive materials such as LCs and hydrogels, a new scenario in thermoplasmonic-based, next generation, photonic components is presented and discussed. Moreover, a new road in thermoplasmonic-driven biomedical applications, by describing compelling and innovative health technologies such as on-demand drug-release and smart face masks with smart nano-assisted destruction of pathogens, is proposed. The latter represents a new weapon in the fight against COVID-19.Thermoplasmonics deals with the generation and manipulation of nanoscale heating associated with noble metallic nanoparticles. To this end, gold nanoparticles (AuNPs) are unique nanomaterials with the intrinsic capability to generate a nanoscale confined light-triggered thermal effect. This phenomenon is produced under the excitation of a suitable light of a wavelength that matches the localized surface plasmonic resonance frequency of AuNPs. Liquid crystals (LCs) and hydrogels are temperature-sensitive materials that can detect the host AuNPs and their photo-induced temperature variations. In this perspective, new insight into thermoplasmonics, by describing a series of methodologies for monitoring, detecting, and exploiting the photothermal properties of AuNPs, is offered. From conventional infrared thermography to highly sophisticated temperature-sensitive materials such as LCs and hydrogels, a new scenario in thermoplasmonic-based, next generation, photonic components is presented and discussed. Moreover, a new road in thermoplasmonic-driven biomedical applications, by describing compelling and innovative health technologies such as on-demand drug-release and smart face masks with smart nano-assisted destruction of pathogens, is proposed. The latter represents a new weapon in the fight against COVID-19.

pdf 7191

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