Latest Publications

Abstract:
As the critical feature of the stick-slip for soft materials, the interfacial Schallamach waves of flexible composite structures are essential for smart tactile sensors to realize sliding perception. Herein, the Schallamach waves of polydimethylsiloxane film/substrate bilayer structures with three substrate stiffnesses regulated by porosities are investigated by setting up in-situ sliding tests and establishing finite element models with mixed-mode cohesive contact. Inhomogeneity in microcontact stiffness disrupts the continuity and synchronization of the Schallamach waves, resulting in non-periodic fluctuations in the contact force. The buckling phenomenon of the film structure marks the transition from stick to slip. This buckling induces a shift at the crack front from normal compressive stress to tensile stress, leading to mixed-mode damage.

Keywords:
Stick-slip,Polydimethylsiloxane film/substrate bilayer structures,Schallamach wave,In-situ sliding test,Mixed-mode cohesive contact model

Abstract:
The development of bone tissue engineering, a field with significant potential, requires a biomaterial with high bioactivity. The aim of this manuscript was to fabricate a nanofibrous poly(L-lactide) (PLLA) scaffold containing nano-hydroxyapatite (nHA) to investigate PLLA/nHA composites, particularly the effect of fiber arrangement and the addition of nHA on the piezoelectric phases and piezoelectricity of PLLA samples. In this study, we evaluated the effect of nHA particles on a PLLA-based electrospun scaffold with random and aligned fiber orientations. The addition of nHA increased the surface free energy of PLLA/nHA (42.9 mN/m) compared to PLLA (33.1 mN/m) in the case of aligned fibers. WAXS results indicated that at room temperature, all the fibers are in an amorphous state indicated by a lack of diffraction peaks and amorphous halo. DSC analysis showed that all samples located in the amorphous/disordered alpha' phase crystallize intensively at temperatures just above the Tg and recrystallize on further heating, achieving significantly higher crystallinity for pure PLLA than for doped nHA, 70 % vs 40 %, respectively. Additionally, PLLA/nHA fibers show a lower heat capacity for PLLA in the amorphous state, indicating that nHA reduces the molecular mobility of PLLA. Moreover, piezoelectric constant d33 was found to increase with the addition of nHA and for the aligned orientation of the fibers. In vitro tests confirmed that the addition of nHA and the aligned orientation of nanofibers increased osteoblast proliferation.

Keywords:
Scaffolds, Tissue engineering, Bone tissue engineering, Smart medicine, Biodegradable polymers, Regenerative medicine

Abstract:
The subject of research is a steel arch-tied bridge at a high-speed railway line in Poland. After the construction was completed, a resonance phenomenon was observed at the bridge, consisting of the occurrence of intense (visible to the unaided eye) undamped vibrations of some vertical hangers in the horizontal direction, transverse to the track axis. These vibrations occurred without the presence of a railway load on the bridge. Before the bridge was put into operation, an acceptance static and dynamic load test was performed, and then the bridge deck vibrations were monitored for a year. The research during dynamic loads testing included both quasi-static (10 km/h) and high-speed (200 km/h) testing train passages. The vertical displacement measurements were carried out in three cross sections of the span, and the acceleration of vibrations on girders and selected hangers was also measured. Next, an innovative system for determining displacements indirectly using inertial sensors (inclinometers and accelerometers) was used for bridge deck vibration monitoring. The primary aim of the research was to investigate the possibility of assessing the safe operation of the bridge using a monitoring system consisting of a limited number of inertial sensors. The second aim was to verify the feasibility of calibrating the numerical model based on the results of dynamic load testing. Numerical analyses of the behavior of the bridge during the passage of trains with speeds up to 200 km/h were carried out. The developed and calibrated numerical model provides additional information about the overall structural vibrations, facilitating the interpretation of outcomes of the monitoring system. No significant impact of hanger vibrations on the monitored displacements and accelerations of the bridge deck vibrations during the passage of trains was found.

Keywords:
Arch-tied railway bridge,Bridge monitoring,Load testing,Bridge vibration,Numerical model calibration

Abstract:
The majority of the current cancer research is based on 2D cell cultures and animal models. These methods have limitations, including different expression of key factors involved in carcinogenesis and metastasis, depending on culture conditions. Addressing these differences is crucial in obtaining physiologically relevant results. Stemness and epithelial-mesenchymal transition (EMT) is linked to the increased invasive potential and metastasis, thus exploring the expression of this markers in a different growth conditions is essential. We report plasticity of expression of selected stem cell and EMT markers in different culture conditions, pointing to the importance of spatial parameters. The most significant difference is the expression of adherent cell junction protein E-cadherin, which changes dramatically between standard 2D culture, floating spheroid culture and matrigel scaffolded culture. As a step towards understanding the reasons causing these discrepancies, we have created a mathematical model of tensions within the 3D bioprinted culture.

Abstract:
The macroscopic behaviors of materials are determined by interactions that occur at multiple lengths and time scales. Depending on the application, describing, predicting, and understanding these behaviors may require models that rely on insights from atomic and electronic scales. In such cases, classical simplified approximations at those scales are insufficient, and quantum-based modeling is required. In this paper, we study how quantum effects can modify the mechanical properties of systems relevant to materials engineering. We base our study on a high-fidelity modeling framework that combines two computationally efficient models rooted in quantum first principles: Density Functional Tight Binding (DFTB) and many-body dispersion (MBD). The MBD model is applied to accurately describe non-covalent van der Waals interactions. Through various benchmark applications, we demonstrate the capabilities of this framework and the limitations of simplified modeling. We provide an open-source repository containing all codes, datasets, and examples presented in this work. This repository serves as a practical toolkit that we hope will support the development of future research in effective large-scale and multiscale modeling with quantum-mechanical fidelity.

Keywords:
DFT, DFTB, Energy range separation, Many-body dispersion, van der Waals interaction, Carbon nanotube, UHMWPE

Abstract:
This work presents a comprehensive examination of the physical mechanisms driving hardening in irradiated face-centered cubic FeNiCr alloys. The evolution of irradiation-induced defects during shear deformation is modeled by atomistic simulations through overlapping cascade simulations, where the nucleation and evolution of dislocation loops is validated by transmission electron microscopy images obtained from irradiated FeNiCr alloys using tandem accelerator. The effect of different shear rates on the microstructure of irradiated materials with a specific focus on the changes in the density of voids and dislocation loops induced by irradiation was analyzed. Additionally, the fundamental interaction processes between single irradiation-induced defects contributing to irradiation hardening, such as voids and dislocation loops in the alloy are explained. The analysis at atomic level indicates that both the dislocation loops and the voids exhibit strengthening effects. Furthermore, the nanometric voids are much stronger obstacles than dislocation loops of comparable size. The mechanism of cutting the voids leads to an increase of voids density and thus contributes to an increase in irradiation hardening. The mechanism of collapse of small voids into dislocation loops leads to decrease of voids density and at the same time increase of loops density. The coupling effect between the density of voids and dislocation loops is determined. Finally, the novel, physical mechanisms-based model of irradiation hardening and dislocation-radiation defect reaction kinetics are developed, which consider the mechanisms of void cutting, void shrink and void collapse to dislocation loop.

Keywords:
Radiation-induced defects,Irradiation hardening,Collision cascades,MD simulations,Radiation defects evolution,Cr-rich alloys

Abstract:
Intervertebral disc (IVD) degeneration is a leading cause of lower back pain (LBP). Current treatments primarily address symptoms without halting the degenerative process. Cell transplantation offers a promising approach for early-stage IVD degeneration, but challenges such as cell viability, retention, and harsh host environments limit its efficacy. This study aimed to compare the injectability and biocompatibility of human nucleus pulposus cells (hNPC) attached to two types of microscaffolds designed for minimally invasive delivery to IVD. Microscaffolds are developed from poly(lactic-co-glycolic acid) (PLGA) using electrospinning and femtosecond laser structuration. These microscaffolds are tested for their physical properties, injectability, and biocompatibility. This study evaluates cell adhesion, proliferation, and survival in vitro and ex vivo within a hydrogel-based nucleus pulposus model. The microscaffolds demonstrate enhanced surface architecture, facilitating cell adhesion and proliferation. Laser structuration improved porosity, supporting cell attachment and extracellular matrix deposition. Injectability tests show that microscaffolds can be delivered through small-gauge needles with minimal force, maintaining high cell viability. The findings suggest that laser-structured PLGA microscaffolds are viable for minimally invasive cell delivery. These microscaffolds enhance cell viability and retention, offering potential improvements in the therapeutic efficiency of cell-based treatments for discogenic LBP.

Abstract:
In this paper, small-scale testing techniques—nanoindentation and micropillar compression—were used to investigate the deformation mechanisms, size effects, and strain rate sensitivity of (100) and (110) single-crystal Gum Metal at the micro/nanoscale. It was observed that the (100) orientation exhibits a significant size effect, resulting in hardness values ranging from 1 to 5 GPa. Conversely, for the (110) orientation, this effect was weaker. Furthermore, the yield strength obtained from the micropillar compression tests was approximately 740 MPa for the (100) orientation and 650 MPa for the (110) orientation. The observed deformations were consistent with the established features of the deformation behavior of body-centered cubic (bcc) alloys: significant strain rate sensitivity with no depth dependence, pile-up patterns comparable to those reported in the literature, and shear along the {112}<111> slip directions. However, the investigated material also exhibited Gum Metal-like high ductility, a relatively low modulus of elasticity, and high yield strength, which distinguishes it from classic bcc alloys.

Abstract:
This paper introduces a first-time investigation into the impact of power ultrasound (PUS)-assisted preparation on the physicochemical and mechanical properties of cement-granulated blast furnace slag (GBFS) composite pastes. Pastes containing deposited GFBS with varying particle size fractions, partially replacing Portland cement, were prepared using PUS (ultrasonic horn tip, 20 kHz, 700 W) in pulse mode in a vertical jacketed glass sonoreactor with closed-circuit cooling. Cement paste incorporating 20 wt.% GBFS as mass substitution with varying particle size fractions was characterized by several physicochemical techniques at different curing ages. Exploring the cement and GBFS interaction induced by PUS, the compressive and flexural strength, the elastic modulus and indentation hardness, the heat of hardening, the mineral composition of hydration products, and the specific surface area BET were evaluated for a curing time of up to 28 days. The grain size distribution of GFBS and the reaction mixture's pH were measured. Both mechanical properties, heat of hydration and nanoporosity exhibited strong sensitivity to PUS treatment. Sonofragmentation of GBFS particles (especially the 125–250 μm fraction) increased with increasing sonication time, resulting in a relative increase of fraction <63 μm and a decrease of fraction >125 μm by 275 % and 60 %, respectively. Using the obtained SEM-EDS data, a simplified mechanism is proposed to explain the effects induced by PUS treatment.

Keywords:
Power ultrasound treatment, Portland cement, Granulated blast furnace slag, Early strength development, C-S-H/C-A-S-H, Seeding effect

Abstract:
The HIFU ablation technique is limited by the long duration of the procedure, which results from the large difference between the size of the HIFU beam’s focus and the tumor size. Ablation of large tumors requires treating them with a sequence of single HIFU beams, with a specific time interval in-between. The aim of this study was to evaluate the biological effects induced in a malignant solid tumor of the rat mammary gland, implanted in adult Wistar rats, during HIFU treatment according to a new ablation plan which allowed researchers to significantly shorten the duration of the procedure. We used a custom, automated, ultrasound imaging-guided HIFU ablation device. Tumors with a 1 mm thickness margin of healthy tissue were subjected to HIFU. Three days later, the animals were sacrificed, and the HIFU-treated tissues were harvested. The biological effects were studied, employing morphological, histological, immunohistochemical, and ultrastructural techniques. Massive cell death, hemorrhages, tissue loss, influx of immune cells, and induction of pro-inflammatory cytokines were observed in the HIFU-treated tumors. No damage to healthy tissues was observed in the area surrounding the safety margin. These results confirmed the efficacy of the proposed shortened duration of the HIFU ablation procedure and its potential for the treatment of solid tumors.

Keywords:
HIFU thermal ablation, breast cancer model, treatment plan, morphology, histology, ultrastructure, immune response, cell death, apoptosis, necrosis

Abstract:
This study presents the process of developing an effective anode material for lithium-ion batteries (LIBs) by usage of Li2TiSiO5 coated with a thin layer of carbon (LTSO/C). The material was prepared through a sol–gel method, where varying amounts of polyvinylpyrrolidone (PVP) were used as a carbon source during the synthesis process. The physicochemical analysis of the LTSO/C samples indicates that as the amount of PVP used during sol–gel synthesis increases, the particle diameter of LTSO decreases. Furthermore, the analysis shows that a thin amorphous carbon layer is deposited on the LTSO surfaces, along with additional carbon networks between the LTSO particles. Based on the electrochemical analysis conducted to optimize the amount of PVP during synthesis, the resulting LTSO/C composite electrode synthesized with 1 g of PVP exhibits a specific capacity of 274.5 mAh·g−1 at 0.1C after 150 cycles, which is quite close to the theoretical capacity. In addition, this LTSO/C electrode demonstrates exceptional electrochemical performance when operated at high rates, surpassing a discharge capacity of 170 mAh g−1 up to 2C. Therefore, the LTSO/C is an excellent choice for high-performance anode material in LIBs.

Keywords:
Li2TiSiO5, Carbon layer, Polyvinylpyrrolidone, Anode material, Lithium-ion batteries, Sol–gel synthesis

Abstract:
The major hindrance to efficient electrocatalytic hydrogen generation from water electrolysis is the sluggish kinetics with corresponding large overvoltage of oxygen evolution reaction. Herein, we report a defective 2D NiCoMoS@Ni(CN)2 core-shell heterostructure derived from Hofmann-type MOF as an efficient and durable high-performance noble metal-free electrocatalyst for hydrazine oxidation reaction (HzOR) in alkaline media. The sluggish oxygen evolution reaction was replaced with a more thermodynamically favourable HzOR, enabling energy-saving electrochemical hydrogen production with 2D NiCoMoS@Ni(CN)2 acting as a bifunctional electrocatalyst for anodic HzOR and cathodic hydrogen generation. Operating at room temperature, the two-electrode electrolyzer delivers 100 mA cm−2 from a cell voltage of just 257 mV, with strong long-term electrochemical durability and nearly 100% Faradaic efficiency for hydrogen evolution in 1.0 M KOH aqueous solution with 0.5 M hydrazine. The density functional theory (DFT) was employed to investigate the origin of catalytic performance and showed that high vacancy creation within the heterointerface endowed NiCoMoS@Ni(CN)2 with favourable functionalities for excellent catalytic performance.

Keywords:
Defect engineering, Core-shell, Electrocatalyst, Hydrazine oxidation, Heterostructure

Abstract:
The measurement and control of the heat transfer of sheet alloys in successive non-isothermal forming cycles is crucial to achieve the desired post-form properties and microstructure, which could not as of yet be realized by using traditional test facilities. In the present research, a novel heat transfer measurement facility was designed to generate and subsequently measure the in-situ heat transfer from a sheet alloy to multi-mediums such as forming tools, air, lubricant and coating. More importantly, the facility was able to use a single sheet alloy sample to perform successive non-isothermal forming cycles, and subsequently obtain high throughput experimental results including the temperature evolution, cooling rate, mechanical properties and microstructures of the alloy. The high throughput in-situ heat transfer measurement facility identified that the cooling rate of AA7075 was 152 °C/s and the mechanical strength was over 530 MPa in the 1st forming cycle. However, it decreased to less than the critical value of 100 °C/s in the successive 10th forming cycle, leading to a low mechanical strength of only 487 MPa. The identified variations that occur in the successive non-isothermal forming cycles would improve the consistency and accuracy of part performance in large-scale manufacturing.

Keywords:
High throughput in-situ measurement,Heat transfer,Successive non-isothermal forming,Sheet alloys,Microstructure

Abstract:
We analyze the three-dimensional (3D) buckling of an elastic filament in a shear flow of a viscous fluid at low Reynolds number and high Péclet number. We apply the Euler-Bernoulli beam (elastica) theoretical model. We show the universal character of the full 3D spectral problem for a small perturbation of a thin filament from a straight position of arbitrary orientation. We use the eigenvalues and eigenfunctions for the linearized elastica equation in the shear plane, found earlier by Liu et al. [Phys. Rev. Fluids 9, 014101 (2024)] with the Chebyshev spectral collocation method, to solve the full 3D eigenproblem. We provide a simple analytic approximation of the eigenfunctions, represented as Gaussian wave packets. As the main result of the paper, we derive the square-root dependence of the eigenfunction wave number on the parameter χ˜ = −η sin 2φ sin2 θ, where

Abstract:
Efficient and sustainable energy conversion depends on the rational design of single-atom catalysts. The control of the active sites at the atomic level is vital for electrocatalytic materials in alkaline and acidic electrolytes. Moreover, fabrication of effective catalysts with a well-defined surface structure results in an in-depth understanding of the catalytic mechanism. Herein, a single atom ruthenium dispersed in nickel-cobalt layered hydroxide (Ru-NiCo LDH) is reported. Through the precise controlling of the atomic dispersion and local coordination environment, Ru-NiCo LDH//Ru-NiCo LDH provides an ultra-low overpotential of 1.45 mV at 10 mA cm−2 for the overall water splitting, which surpasses that of the state-of-the-art Pt/C/RuO2 redox couple. Density functional theory calculations show that Ru-NiCo LDH optimizes hydrogen evolution intermediate adsorption energies and promotes O-O coupling at a Ru-O active site for oxygen evolution, while Ni serves as the water dissociation site for effective water splitting. As a potential model, Ru-NiCo LDH shows enhanced water splitting performance with potential for the development of promising water-alkaline catalysts.

Abstract:
Bacterial keratitis (BK) is a severe eye infection commonly associated with Staphylococcus aureus (S. aureus), posing a significant risk to vision, especially among contact lens wearers. This research introduces a novel smart nanoplatform (deMS@cNF), developed from demineralized mussel shells (deMS) and reinforced with chitin (CT) nanofibrils, specifically designed for portable photothermal disinfection of contact lenses. The nanoplatform leverages the photothermal properties of eumelanin in mussel shells (MS), which, when activated by a simple bike flashlight, rapidly heats to temperatures up to 95 °C, effectively destroying bacterial contamination. In vitro tests demonstrate that the nanoplatform is biocompatible and non-toxic, making it suitable for medical applications. This study highlights an innovative approach to converting marine biowaste into a safe, effective, and low-cost portable method for disinfecting contact lenses, showcasing the potential of the deMS@cNF platform for broader antimicrobial applications.

Abstract:
Background: Chatbots using the Large Language Model (LLM) generate human responses to questions from all
categories. Due to staff shortages in healthcare systems, patients waiting for an appointment increasingly use
chatbots to get information about their condition. Given the number of chatbots currently available, assessing the
responses they generate is essential.
Methods: Five chatbots with free access were selected (Gemini, Microsoft Copilot, PiAI, ChatGPT, ChatSpot) and
blinded using letters (A, B, C, D, E). Each chatbot was asked questions about cardiology, oncology, and psoriasis.
Responses were compared to guidelines from the European Society of Cardiology, American Academy of
Dermatology and American Society of Clinical Oncology. All answers were assessed using readability scales
(Flesch Reading Scale, Gunning Fog Scale Level, Flesch-Kincaid Grade Level and Dale-Chall Score). Using a 3-
point Likert scale, two independent medical professionals assessed the compliance of the responses with the
guidelines.
Results: A total of 45 questions were asked of all chatbots. Chatbot C gave the shortest answers, 7.0 (6.0 – 8.0), and Chatbot A the longest 17.5 (13.0 – 24.5). The Flesch Reading Ease Scale ranged from 16.3 (12.2 – 21.9)
(Chatbot D) to 39.8 (29.0 – 50.4) (Chatbot A). Flesch-Kincaid Grade Level ranged from 12.5 (10.6 – 14.6) (Chatbot A) to 15.9 (15.1 – 17.1) (Chatbot D). Gunning Fog Scale Level ranged from 15.77 (Chatbot A) to 19.73 (Chatbot D). Dale-Chall Score ranged from 10.3 (9.3 – 11.3) (Chatbot A) to 11.9 (11.5 – 12.4) (Chatbot D).
Conclusion: This study indicates that chatbots vary in length, quality, and readability. They answer each question
in their own way, based on the data they have pulled from the web. Reliability of the responses generated by
chatbots is high. This suggests that people who want information from a chatbot need to be careful and verify the answers they receive, particularly when they ask about medical and health aspects.

Keywords:
Chatbots,Readability,Cardiovascular health,Oncology

Abstract:
Rational design of novel antibody therapeutics against viral infections such as coronavirus relies on surface complementarity and high affinity for their effectiveness. Here, we explore an additional property of protein complexes, the intrinsic mechanical stability, in SARS-CoV-2 variants when complexed with a potent antibody. In this study, we utilized a recent implementation of the GōMartini 3 approach to investigate large conformational changes in protein complexes with a focus on the mechanostability of the receptor-binding domain (RBD) from WT, Alpha, Delta, and XBB.1.5 variants in complex with the H11-H4 nanobody. The analysis revealed moderate differences in mechanical stability among these variants. Also, we identified crucial residues in both the RBD and certain protein segments in the nanobody that contribute to this property. By performing pulling simulations and monitoring the presence of specific native and non-native contacts across the protein complex interface, we provided mechanistic insights into the dissociation process. Force-displacement profiles indicate a tensile force clamp mechanism associated with the type of protein complex. Our computational approach not only highlights the key mechanostable interactions that are necessary to maintain overall stability, but it also paves the way for the rational design of potent antibodies that are mechanostable and effective against emergent SARS-CoV-2 variants.

Keywords:
SARS-CoV-2, GōMartini 3, Nanomechanics, Protein complexes, protein engineering, MD, native contacts

Abstract:
The dynamics of a single highly elastic fibre settling under gravity in a very viscous fluid is studied numerically. We employ the bead model and multipole expansion of the Stokes equations, corrected for lubrication that is implemented in the precise Hydromultipole numerical codes. Four attracting regular dynamical modes of highly elastic fibres are found: two stationary shapes (one translating and the other rotating and translating), and two periodic oscillations around such shapes. The phase diagram of these modes is presented. It illustrates that the existence of each mode depends not only on the elasto-gravitation number but also on the fibre aspect ratio. Characteristic time scales, fibre deformation patterns and motion in the different modes are determined.

Keywords:
stokesian dynamics, particle/fluid flows

Abstract:
The paper presents and discusses the results of a study of the thermal properties of cement composites with different contents of magnetite aggregate (0%, 20%, 40% and 60% by volume). The effect of grain size on the evaluated thermal properties was also investigated. For this purpose, concrete containing 50% by volume of magnetite aggregate with four different fractions (1–2 mm, 2–4 mm, 4–8 mm and 8–16 mm) was used. Thermal parameters were evaluated on specimens fully saturated with water and dried to a constant mass at 65 °C. The series with varying grain sizes of magnetite achieved thermal conductivity values in the range of 2.76–3.03 W/(m·K) and 2.00–2.21 W/(m·K) at full water saturation and after drying to a constant mass, respectively. In the case of the series with 20% magnetite by volume, the thermal conductivity was 2.65 W/(m·K) and 1.99 W/(m·K) for the material fully saturated with water and dried to a constant mass, respectively. The series with a 60% volume share of magnetite obtained values of this parameter of 3.47 W/(m·K) and 2.66 W/(m·K), respectively, under the same assumptions.

Keywords:
shielding concrete, thermal properties, magnetite aggregate

Abstract:
In this work, tantalum-doped tungsten boride ceramic coatings were deposited from a single sputtering target with the radio frequency (RF) and high-power impulse magnetron sputtering (HiPIMS) methods. Two-inch torus targets were synthesised from pure elements with the spark plasma sintering (SPS) method with a stoichiometric composition of W1-xTaxB2.5 (x = 0, 0.08, 0.16, 0.24). Films were deposited with RF and HiPIMS power suppliers at process temperatures from RT to 600 °C. The substrate heating and the energy of the ionised material impacting the substrate increase the surface diffusivity of adatoms and are crucial in the deposition process. The results of SEM and XRD investigations clearly show that the addition of tantalum also changes the microstructure of the deposited films. The coatings without tantalum possess a finer microstructure than those with 24% of tantalum. The structure of films is homogeneous along the film thickness and composed mainly of columns with a (0001) preferred orientation. Deposited coatings are composed mainly of P6/mmm α-WB2 structures. The analysis of nanoindentation results allowed us to determine that ceramic coatings obtained with the HiPIMS method possess hardness above 41 GPa and a ratio of hardness to reduced Young modulus above 0.1. The thickness of HiPIMS-deposited films is relatively small: only around 60% of the RF magnetron sputtered coatings even when the average power input was two times higher. However, it has been shown that the RF coatings require heating the substrate above 400 °C to obtain a crystalline structure, while the HiPIMS method allows for a reduction of the substrate temperature to 300 °C.

Keywords:
RF magnetron sputtering, HiPIMS magnetron sputtering, Superhard ceramic coatings, Transition metal borides, Deposition temperature

Abstract:
The demand for pseudopotentials constructed for a given exchange-correlation (XC) functional far exceeds the supply, necessitating the use of those commonly available. The number of XC functionals currently available is in the hundreds, if not thousands, and the majority of pseudopotentials have been generated for LDA and PBE. The objective of this study is to identify the error in the determination of the mechanical and structural properties (lattice constant, cohesive energy, surface energy, elastic constants, and bulk modulus) of crystals calculated by DFT with such inconsistency. Additionally, this study aims to estimate the performance of popular XC functionals (LDA, PBE, PBEsol, and SCAN) for these calculations in a consistent manner.

Keywords:
DFT, pseudopotentials, exchange–correlation functionals

Abstract:
In this paper, 20 µm and 40 µm thick aluminide coatings were deposited on MAR-M247 nickel-based superalloy through the chemical vapor deposition (CVD) process in a hydrogen protective atmosphere for 4 h and 12 h, respectively, at a temperature of 1040 °C and an internal pressure of 150 mbar. The effect of aluminide coating thickness on the high-temperature performance of the MAR-M247 nickel-based superalloy was examined during a fatigue test at 900 °C. After high-temperature testing, the specimens were subjected to fractographic analysis to reveal the damage mechanisms. No significant effect of coating thickness was found since the material exhibited a similar service life throughout the fatigue test when subjected to the same stress amplitude. One should stress that the coating remained well adhered after specimen fracture, confirming its effectiveness in protecting the material against high-temperature oxidation.

Keywords:
fatigue, aluminide coatings, nickel alloys , high-temperature performance

Abstract:
Hierarchical nanostructures fabricate by electrospinning in combination with light-responsive agents offer promising scenarios for developing novel activable antibacterial interfaces. This study introduces an innovative antibacterial face mask developed from poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanofibers integrated with indocyanine green (ICG), targeting the urgent need for effective antimicrobial protection for community health workers. The research focuses on fabricating and characterizing this nanofibrous material, evaluating the mask's mechanical and chemical properties, investigating its particle filtration, and assessing antibacterial efficacy under photothermal conditions for reactive oxygen species (ROS) generation. The PHBV/ICG nanofibers are produced using an electrospinning process, and the nanofibrous construct's morphology, structure, and photothermal response are investigated. The antibacterial efficacy of the nanofibers is tested, and substantial bacterial inactivation under both near-infrared (NIR) and solar irradiation is demonstrated due to the photothermal response of the nanofibers. The material's photothermal response is further analyzed under cyclic irradiation to simulate real-world conditions, confirming its durability and consistency. This study highlights the synergistic impact of PHBV and ICG in enhancing antibacterial activity, presenting a biocompatible and environmentally friendly solution. These findings offer a promising path for developing innovative face masks that contribute significantly to the field of antibacterial materials and solve critical public health challenges.

Abstract:
Fast and high-quality ultrasound imaging allows to increase the effectiveness of detecting tissue changes at the initial stage of disease. The aim of the study was to assess the quality of ultrasound imaging using mutually
orthogonal, complementary Golay coded sequences (MOCGCS). Two 16-bits MOCGCS sets were implemented in the Verasonics Vantage™ scanner. Echoes from a perfect reflector, a custom-made nylon wire phantom,a tissue-mimicking phantom, and in-vivo scans of abdominal aorta and common carotid artery were recorded.Three parameters of the detected MOCGCS echoes: signal-to-noise ratio (SNR), side-lobe level (SLL), and axial resolution were evaluated and compared to the same parameters of the echoes recorded using standard
complementary Golay sequences (CGS) and a short, one sine cycle pulse. The results revealed that MOCGCS
transmission maintained comparable echo quality metrics (SNR, SLL, and axial resolution) compared to CGS
and short pulses. Notably, both MOCGCS and CGS offered similar SNR improvements (5 dB–9 dB) in compar-ison to the short pulse for wires placed at depths up to 8 cm. Analysis of axial resolution, estimated at the full width at half maximum level, revealed near-identical values for all transmitted signals (0.17 μs for MOCGCS,0.16 μs for CGS, and 0.18 μs for short pulse). MOCGCS implementation in ultrasound imaging offers the po-tential to significantly reduce image reconstruction time while maintaining image quality comparable to CGS sequences. In the experimental study we have shown that MOCGCS offers advantages over conventional CGS by enabling two times faster data acquisition and image reconstruction without compromising image quality.

Keywords:
coded excitation, Golay codes, synthetic aperture

Abstract:
Metal-ceramic composites by their nature have thermal residual stresses at the micro-level, which can compromise the integrity of structural elements made from these materials. The evaluation of thermal residual stresses is therefore of continuing research interest both experimentally and by modeling. In this study, two functionally graded aluminum alloy matrix composites, AlSi12/Al2O3 and AlSi12/SiC, each consisting of three composite layers with a stepwise gradient of ceramic content (10, 20, 30 vol%), were produced by powder metallurgy. Thermal residual stresses in the AlSi12 matrix and the ceramic reinforcement of the ungraded and graded composites were measured by neutron diffraction. Based on the X-ray micro-computed tomography (micro-XCT) images of the actual microstructure, a series of finite element models were developed to simulate the thermal residual stresses in the AlSi12 matrix and the reinforcing ceramics Al2O3 and SiC. The accuracy of the numerical predictions is high for all cases considered, with a difference of less than 5 % from the neutron diffraction measurements. It is shown numerically and validated by neutron diffraction data that the average residual stresses in the graded AlSi12/Al2O3 and AlSi12/SiC composites are lower than in the corresponding ungraded composites, which may be advantageous for engineering applications.

Keywords:
Finite element modeling,Micro-XCT,Thermal residual stress,Hot pressing,Aluminum matrix composites

Abstract:
Direct Metal Laser Sintered Haynes 282 specimens as well as wrought ones were subjected to high-temperature exposure at 1000 °C for 100h in air to compare their oxidation behaviour. The specimens were removed from the furnace after 1h, 5h, 25h, 50h and 100h to reveal and study oxidation mechanisms through morphological and cross-sectional examination by using scanning electron microscopy with energy dispersive spectroscopy attachment and X-ray diffraction. Microstructural studies revealed that the oxidation kinetics, determined by changes in thickness scale and depth of aluminium diffusion zone, were mainly driven by the formation of Cr2O3 for the wrought material, and TiO2 for DMLS one. The wrought material was characterized by the oxidation rate equal to 0.96 and followed the logarithmic law. On the other hand, DMLS-manufactured Haynes 282 exhibited oxidation rate of 0.90 and follows the linear law for the thickness scale considerations. However, when the depth of aluminium diffusion was investigated, it had an oxidation rate of 0.87 and followed cubic law.

Abstract:
Background

Metal Laser Powder Bed Fusion Melting (LPBF-M) is considered economically viable and environmentally sustainable because of the possibility of reusing the residual powder feedstock leftover in the build chamber after a part build is completed. There is however limited information on the fatigue damage development of LPBF-M samples made from reused feedstock.
Objective

In this paper, the stainless steel 316 L (SS316L) powder feedstock was examined and characterised after 25 reuses, following which the fatigue damage development of material samples made from the reused powder was assessed.
Methods

The suitability of the powder to LPBF-M technology was evaluated by microstructural observations and measurements of Hall flow, apparent and tapped density as well as Carr’s Index and Hausner ratio. LPBF-M bar samples in three build orientations (Z – vertical, XY – horizontal, ZX – 45° from the build plate) were built for fatigue testing. They were then subjected to fatigue testing under load control using full tension and compression cyclic loading and stress asymmetry coefficient equal to -1 in the range of stress amplitude from ± 300 MPa to ± 500 MPa.
Results

Samples made from reused powder (25 times) in the LPBF-M process exhibited similar fatigue performance to fresh unused powder although a lower ductility for vertical samples was observed during tensile testing. Printing in horizontal (XY) and diagonal (ZX) directions, with reused powder, improved the service life of the SS316L alloy in comparison to the vertical (Z).
Conclusions

Over the 25 reuses of the powder feedstock there was no measurable difference in the flowability between the fresh (Hall Flow: 21.4 s/50 g) and reused powder (Hall Flow: 20.6 s/50 g). This confirms a uniform and stable powder feeding process during LPBF-M for both fresh and reused powder. The analysis of fatigue damage parameter, D, concluded cyclic plasticity and ratcheting to be the main mechanism of damage.

Keywords:
SS316L ,Stainless steel,Fatigue ,Additive manufacturing,Laser Powder Bed Fusion Melting (LPBF-M)

Abstract:
In this paper, the effectiveness of the eddy current methodology for crack detection in MAR 247 nickel-based superalloy with aluminide coatings subjected to cyclic loading was investigated. The specimens were subjected to force-controlled fatigue tests under zero mean level, constant stress amplitude from 300 MPa to 600 MPa and a frequency of 20 Hz. During the fatigue, a particular level of damage was introduced into the material leading to the formation of microcracks. Subsequently, a new design of probe with a pot core was developed to limit magnetic flux leakage and directed it towards the surface under examination. The suitability of the new methodology was further confirmed as the specimens containing defects were successfully identified. The changes in probe resistance values registered for damaged specimens ranged approximately from 8 to 14%.

Keywords:
Nickel alloys, Aluminide coating, Non-destructive testing, Eddy current testing

Abstract:
Concrete used in nuclear applications faces significant durability challenges due to degradation from radiation, thermal stresses, and chemical reactions. These issues highlight the critical need for impermeable concrete shields to prevent radioactive leaks and protect against harmful radiation. This study examines how concrete composition affects gas permeability and gamma radiation shielding properties. Three coarse aggregates—amphibolite (reference), magnetite, and serpentine—and two cement types (ordinary and slag) were tested, with concrete densities ranging from 2309 to 3538 kg/m3. Gas permeability was measured using a Cembureau-type constant head permeameter, and gamma shielding was assessed through the linear attenuation coefficient (µ) and half-value layer (HVL) at 137Cs decay energies. The results revealed significant variations in gas permeability and gamma ray shielding based on aggregate and cement type, with observable relationships between gas permeability, HVL, and concrete density. The results obtained from the presented research will contribute to increasing the safety, durability and cost-effectiveness of concrete constructions and maintenance of nuclear facilities.

Keywords:
Heavyweight aggregate, Hydrogen-bearing aggregate, Shielding concrete, Gas permeability, Gamma ray attenuation, Microstructure, ITZ

Abstract:
The quality parameters of surface layers synthesised using electrospark alloying (ESA) technology were analysed in this paper. The main focus was on the influence of equipment energy parameters on structure formation, specifically the effect of discharge energy and productivity. Microstructural analysis of the modified surface of C40 steel after nitriding by ESA using a paste containing nitrogen compounds injected into the interelectrode gap was conducted. The layer structure for all studied ESA parameters includes three areas: the upper “white layer”, the diffusion zone below it, and the substrate. The roughness of the surface is Ra ∼ 0.9 μm at low discharge energy Wp = 0.13 J and Ra ∼ 6 μm at Wp = 3.4 J. The microhardness, continuity, and surface roughness of the layers varied with Wp. The influence of ESA productivity on the structure was studied. The thickness of the hardened layer and the diffusion zone, as well as the microhardness and continuity, are affected by reduced productivity. For the same discharge energy, the thickness of the hardened layer increases by 10-18% with a decrease in productivity compared to the classical mode.

Keywords:
electrospark alloying, discharge energy, productivity, coating, structure

Abstract:
Bone repair and regeneration require physiological cues, including mechanical, electrical, and biochemical activity. Many biomaterials have been investigated as bioactive scaffolds with excellent electrical properties. Amongst biomaterials, piezoelectric materials (PMs) are gaining attention in biomedicine, power harvesting, biomedical devices, and structural health monitoring. PMs have unique properties, such as the ability to affect physiological movements and deliver electrical stimuli to damaged bone or cells without an external power source. The crucial bone property is its piezoelectricity. Bones can generate electrical charges and potential in response to mechanical stimuli, as they influence bone growth and regeneration. Piezoelectric materials respond to human microenvironment stimuli and are an important factor in bone regeneration and repair. This manuscript is an overview of the fundamentals of the materials generating the piezoelectric effect and their influence on bone repair and regeneration. This paper focuses on the state of the art of piezoelectric materials, such as polymers, ceramics, and composites, and their application in bone tissue engineering. We present important information from the point of view of bone tissue engineering. We highlight promising upcoming approaches and new generations of piezoelectric materials.

Keywords:
piezoelectricity, scaffolds, smart scaffolds, PVDF, PLLA, PVDF-TRFE, collagen, keratin, tissue engineering, bone tissue engineering, smart medicine, regenerative medicine

Abstract:
Addressing critical tissue defects treatment remains a pressing challenge in medicine and bioengineering. Tissue engineering (TE) scaffolds, characterized by porous architectures suitable to cell growth, is a pivotal solution. Recent advances in additive techniques have revolutionized scaffold fabrication, enabling precise control over complex porous structures. This study conducts a comprehensive analysis of hierarchically ordered melt electrospun written (MEW) TE scaffolds, elucidating the relationships between fabrication parameters and their morphological and mechanical properties. Leveraging the phenomenon of melt jet deposit buckling, characteristic hierarchically ordered porous architectures were attained. The study explores the fabrication potential of hierarchically ordered porous MEW architectures across varied voltages, feed rates, and needle sizes. Morphometric parameters, including percent porosity, density of fiber intersections, and fiber diameter, were identified. It was revealed that for feed rates exceeding 20 mm/s, resultant fiber diameters were unaffected by voltage. However, increasing voltage leads to noticeable reduction of mesh stiffness due to the coiled fibers presence. Exceptions occur at the feed rate of 20 mm/s and for needle G24, where stiffness surpasses those of regular primary pattern, which could be attributed to increased number of fiber interconnections.

Keywords:
MEW, Hierarchically ordered meshes, Coiled architectures, Entangled meshes

Abstract:
The global scarcity of drinking water is an emerging problem associated with increasing pollution with many chemicals from industry and rapid microbial growth in aquatic systems. Despite the wide availability of conventional water and wastewater treatment methods, many limitations and challenges exist to overcome. Applying technology based on microbubbles (MBs) and nano-bubbles (NBs) offers ecological, fast, and cost-effective water treatment. All due to the high stability and long lifetime of the bubbles in the water, high gas transfer efficiency, free radical generation capacity, and large specific surface areas with interface potential of generated bubbles. MBs and NBs-based technology are attractive solutions in various application areas to improve existing water and wastewater treatment processes including industrial processes. In this paper, recent progress in NBs and MBs technology in water purification and wastewater treatment along with fundamentals, application, challenges, and future research were comperhensively discussed.

Keywords:
Nanobubbles, Microbubbles, MNB, Wastewater treatment, Water pollution utilization

Abstract:
NiTi exhibits an excellent wear resistance, which can be further enhanced by ion implantation. However, there are some limitations to the implantation effects: only a thin layer of about 100 nm can be created. In this paper, the effect of nitrogen ion implantation on the NiTi wear response is investigated. The different loads and durations of tests are taken into account to show that the implanted layer has the most beneficial effect only in a certain range of contact pressure. It was found that the wear volume changes in a nonlinear manner with respect to the load and sliding length, for both non- and implanted samples. For the latter, two distinct stages can be distinguished in the wear process: an initial stage characterized by a low wear-rate and a low coefficient of friction, and a second stage in which the wear-rate drastically increases. The duration of the first stage is longer for lower loads. This specific behavior is explained by differences in the hardness distribution, energy dissipation due to the normal load, and differences in the microstructure of the wear tracks. Our results show that the lifetime of NiTi can be improved by ion implantation, thus boding well for applications in harsh environments.

Keywords:
ion implantation, NiTi shape memory alloy, sliding wear, pseudoelasticity, abrasion, dry friction, surface treatments

Abstract:
We present a nonlinear finite element analysis to investigate the buckling and post-buckling behaviour of functionally graded material (FGM) plates resting on the elastic foundation. The material properties are assumed to vary gradually across the thickness according to a power law distribution. The starting point of the investigation is the generalized third-order plate theory and the Vlasov model of elastic foundation having properties varying throughout the depth. The plates are subjected to bending to verify the formulation and compression loads including buckling and post-buckling analysis to investigate the influence of various parameters on the structural response. Key words: FGM plate, elastic foundation, post-buckling, nonlinear finite element analysis.

Keywords:
FGM plate, elastic foundation, post-buckling, nonlinear finite element analysis.

Abstract:
In this work, the classical concept of symmetry limited to geometric objects (figures and solids), which originated from ancient Greece, has been extended to allow for symmetry studies in other types of objects.By introducing the concepts of limiting point groups and kinematic elements characteristic for a studied object, it was determined what types of symmetries are exhibited by an electric field and a magnetic field. It was established that in order for a phenomenon to occur, a characteristic symmetry of a medium must be consistent with the characteristic symmetry of the phenomenon occurring in it. It was also determined that the symmetry elements of the causes must be found in the symmetry of their effects.

Keywords:
symmetry, dissymmetry, Curie limiting point groups, symmetry of causes and effects, symmetry of physical fields, characteristic symmetry of phenomenon, characteristic symmetry of medium

Abstract:
Poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP)-sodium thiocyanate (NaSCN) solid polymer electrolytes containing different weight ratios of ionic liquid (IL)—tributylmethylphosphonium iodide (TBMPI) were prepared using solution-cast approach. Electrochemical impedance data indicates that increasing ionic liquid into polymer electrolyte matrix increases ionic conductivity and the maximum value of ionic conductivity was obtained at 150 wt% TBMPI, having conductivity value of 8.3 × 10−5 S cm−1. The dielectric measurement supports our conductivity data. Ionic transference number measurement affirms this system to be predominantly ionic in nature, while electrochemical stability window (ESW) was found to be 3.4 V. Polarized optical microscopy (POM) along with differential scanning calorimetry (DSC) suggest suitability of TBMPI as plasticizer, while infrared spectroscopy (FTIR) confirms ion interaction, complexation, and composite nature. The thermogravimetric analysis (TGA) shows thermal stability of these ionic liquid-doped polymer electrolytes (ILDPEs). Using maximum conducting ILDPE, a sandwiched supercapacitor has been fabricated which shows stable performance as high as 228 Fg−1 using cyclic voltammetry (CV).

Keywords:
capacitance, ionic conductivity, ionic liquid (IL), solid polymer electrolyte (SPE), supercapacitor (SC)

Abstract:
This paper provides a comprehensive overview of the influence of 1-Butyl-1-Methylpyrrolidinium Trifluoromethanesulfonate (BMPyrrOTf)-ionic liquid on a new polymer electrolyte where Polyethylene oxide (PEO) as host and ammonium iodide (NH4I) as salt. These IL-doped solid polymer electrolyte were prepared using solution cast technique. Various characterisation techniques have been utilized to evaluate the qualitative and quantitative estimation of polymer electrolyte like Polarized microscopy (POM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Linear sweep voltammetry (LSV), Ionic transference no. (tion) and Impedance spectroscopy. Doping IL increases conductivity and highest achieve at 8 wt% of BMPyrrOTF with conductivity value reaches upto 4.15 × 10–5 S/cm at. Using Wagner’s polarization method, Ionic transference measurement support ionic conduction while stable potential window has further affirmed good electrochemical stability of films. The highest conducting IL-enriched polymer electrolyte sandwiched low-cost dye-sensitized solar cells (DSSCs) and electric double layer capacitors (EDLCs) have been developed, and their performance is conveniently appropriate.

Abstract:
Molybdenum sulfide–oxide (MoS2, MS) emerges as the prime electrocatalyst candidate demonstrating hydrogen evolution reaction (HER) activity comparable to platinum (Pt). This study presents a facile electrochemical approach for fabricating a hybrid copper (Cu)/MoS2 (CMS) nanos- tructure thin-film electrocatalyst directly onto nickel foam (NF) without a binder or template. The synthesized CMS nanostructures were characterized utilizing energy-ispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), X-ray diffraction (XRD), and electrochemical methods. The XRD result revealed that the Cu metal coating on MS results in the creation of an extremely crys-talline CMS nanostructure with a well-defined interface. The hybrid nanostructures demonstrated
higher hydrogen production, attributed to the synergistic interplay of morphology and electron dis-tribution at the interface. The nanostructures displayed a significantly low overpotential of −149 mV at 10 mA cm−2 and a Tafel slope of 117 mV dec−1, indicating enhanced catalytic activity compared to pristine MoS2.This research underscores the significant enhancement of the HER performance and
conductivity achieved by CMS, showcasing its potential applications in renewable energy.

Keywords:
electrodeposition, hydrogen evolution reactions, catalytic activity, Cu/MoS2 nanostructures

Abstract:
The ability of piezoelectric materials to convert mechanical energy into electric energy and vice versa has made them desirable in the wide range of applications that oscillate from medicine to the energetics industry. Their implementation in optical communication is often connected with the modulation or other manipulations of the light signals. In this article, the recent advancements in the field of piezoelectrics-based devices and their promising benefits in optical communication are explored. The application of piezoelectrics-based devices in optical communication allows dynamic control, modulation, and manipulation of optical signals that lead to a more reliable transmission. It turns out that a combination of artificial-intelligence-based algorithms with piezoelectrics can enhance the performance of these devices, including optimization of piezoelectric modulation, adaptive signal processing, control of optical components, and increase the level of energy efficiency. It can enhance signal quality, mitigate interference, and reduce noise-connected issues. Moreover, this technological fusion can increase the security of optical communication systems. Finally, the potential future research lines are determined.

Abstract:
Functional antibacterial textiles fabricated from a hybrid of organic waste-derived and bio-inspired materials offer sustainable solutions for preventing microbial infections. In this work, we developed a novel antibacterial textile created through the valorization of spent coffee grounds (SCG). Electrospinning and electrospraying techniques were employed to integrate the biowaste within a polymeric nanofiber matrix, ensuring uniform particle distribution and providing structural support for enhanced applicability. Modification with polydopamine (PDA) significantly enhanced the textile's photothermal performance. Specific attention was paid to understanding the relation between temperature change and key variables, including the surrounding liquid volume, textile layer stacking, and applied laser power. Developed platforms demonstrated excellent photothermal stability. While the SCG-based textile demonstrated exceptional biocompatibility, the PDA-modified textile effectively eradicated Staphylococcus aureus (S. aureus) under near-infrared (NIR) irradiation. The developed textiles in our work demonstrate a dynamic balance between biocompatibility and on-demand antibacterial functionality, offering adaptable solutions in accordance with the desired application.

Keywords:
Organic waste valorization, Spent coffee grounds, Micro-nanostructured textiles, Bio-inspired photothermal agents, Polydopamine, Antibacterial textiles

Abstract:
W artykule przedstawiono program badawczy mający na celu wstępne określenie potencjału technologii iPAD-LiDAR w inwentaryzacji obiektów budowlanych.
Autorzy skupili się na wykorzystaniu komercyjnie dostępnych urządzeń (telefonów komórkowych
i tabletów) wyposażonych w sensor LiDAR. Urządzenia takie można potraktować jako nisko kosztowe aparaty pomiarowe i zastosować do pomiarów inżynierskich. Pierwszym możliwym obszarem wykorzystania omawianych urządzeń są szeroko rozumiane inwentaryzacje budowlane, które przy wykonywaniu ich tradycyjnymi metodami zawsze wiążą się z dużym
nakładem pracy. Automatyzacja tego procesu oraz jakość i ilość danych pozyskanych przy
wykonywaniu inwentaryzacji tworzy zupełnie nową rzeczywistość techniczną i związane z tym
możliwości pomiarowo-diagnostyczne.

Keywords:
iPAD, LiDAR, skaning, tablet, nisko kosztowy

Abstract:
This work presents a synthesis of iron nanochains through magnetic-field-induced reduction reaction performed with sodium borohydride in water, ethanol and isopropanol. After their preparation, the nanomaterials obtained in three different processes are washed several times in ethanol and acetone to remove side-products. The performed cleaning step is very sufficient for water-based synthesis of iron nanochains. In contrary, the nanostructures obtained in ethanol and isopropanol contain a significant amount of sodium chlorides which is hard to dispose. Moreover, the use of ethanol and isopropanol solvents causes the reduction of nanochains’ diameters. Both the presence of sodium chlorides and the reduction of diameter size result in the decrease of saturation magnetization of iron nanochains and the increase of their coercivities.

Keywords:
One-dimensional nanostructures, Iron nanochains, Magnetic materials, Magnetic-field-induced synthesis

Abstract:
Recently, there has been a surge of interest in developing new types of photothermal materials driven by the ongoing demand for efficient energy conversion, environmental concerns, and the need for sustainable solutions. However, many existing photothermal materials face limitations such as high production costs or narrow absorption bands, hindering their widespread application. In response to these challenges, researchers have redirected their focus toward harnessing the untapped potential of organic waste-derived and bioderived materials. These materials, with photothermal properties derived from their intrinsic composition or transformative processes, offer a sustainable and cost-effective alternative. This review provides an extended categorization of organic waste-derived and bioderived materials based on their origin. Additionally, we investigate the mechanisms underlying the photothermal properties of these materials. Key findings highlight their high photothermal efficiency and versatility in applications such as water and energy harvesting, desalination, biomedical applications, deicing, waste treatment, and environmental remediation. Through their versatile utilization, they demonstrate immense potential in fostering sustainability and support the transition toward a greener and more resilient future. The authors’ perspective on the challenges and potentials of platforms based on these materials is also included, highlighting their immense potential for real-world implementation.

Keywords:
photothermal materials, organic waste valorization, bioderived materials

Abstract:
The paper presents an attempt to assess the microstructure and mechanical properties by means of the magnetic Barkhausen noise (MBN) method. The experimental program was supplemented by metallographic examinations and hardness tests. It has been concluded that the MBN method can be used for non-destructive characterization of both single and two-phase steels used in the automotive industry. It was also found that the microstructure of steel can be distinguished using the shape of BN envelope and two magnetic parameters: Ubpp1 and Ug1. On the other hand, the hardness and ultimate tensile strength are described successfully by the Ug1/Ubpp1 parameter.

Keywords:
microstructure, mechanical properties, Barkhausen noise, non-destructive method

Abstract:
Vehicle–road coupled system is inherently time–varying, and its responses are traditionally calculated using time–domain methods which involves significant computational effort. Aiming to improve the efficiency of response calculation for the coupled system, this paper proposes a fast calculation method in frequency domain, based on the newly developed moving frequency response function (FRF). Firstly, considering the vibration characteristics of an infinitely long road, the road response is straightforwardly expressed using the road impulse response function (IRF). Subsequently, the concept of the road moving IRF is proposed and derived with respect to the moving observation points. The moving FRF is then obtained by applying Fourier transform, which allows the responses of the road moving observation points to be established in frequency domain for fast calculation under moving loads. Furthermore, by analyzing the vehicle–road coupled vibrations, based on the vehicle FRF and road moving FRF, a formula for the vehicle–road coupling force is derived in frequency domain, along with an expression for the responses at the vehicle–road contact points. Finally, the approach is illustrated in numerical simulations of vehicle–road coupled systems, and its computational efficiency and accuracy are verified through comparison with currently popular methods.

Keywords:
vehicle-road coupled vibration, frequency domain, frequency response function, impulse response function, numerical simulations

Abstract:
This paper discusses the science of material effort from the historical viewpoint. Two gen eral scientific tools: the geometrical descriptive method of Mohr, and the energetic method of Huber are compared and evaluated from the very beginning. Three appropriate stress invariants are taken into account: stress intensity, stress triaxiality and stress shearness. Es pecially, much attention is devoted to explanation of the stress shearness invariant, which aims at describing the Lode parameter in a more analytical manner. Two different tools of finding a proper yield surface which contains the above mentioned three stress invariants are discussed in the literature perspective. In particular, the three-parameter yield surface, called the Burzyński-Pęcherski hypothesis is researched and explained from this new of point view.

Keywords:
Tresca-Mohr hypothesi, Beltrami-Huber, Mises, Burzyński Hypothesis, Lode parameter

Abstract:
The superposition of causal orders shows promise in various quantum technologies. However, the fragility of quantum systems arising from environmental interactions, leading to dissipative behavior and irreversibility, demands a deeper understanding of the possible instabilities in the coherent control of causal orders. In this work, we employ a collisional model to investigate the impact of an open control system on the generation of interference between two causal orders. We present the environmental instabilities for the switch of two arbitrary quantum operations and examine the influence of environmental temperature on each potential outcome of control post-selection. Additionally, we explore how environmental instabilities affect protocol performance, including switching between mutually unbiased measurement observables and refrigeration powered by causal order superposition, providing insights into broader implications.

Abstract:
In the article, investigation is carried out at the second stage of aluminizing, when a consistent substance containing aluminium powder (the first option) or graphite powder and aluminium powder (the second option) is applied to the surface that has undergone aluminizing at the first stage, before further electrospark alloying with an aluminium electrode, and, regardless of the drying of the consistent substance, the aluminizing process is carried out at a discharge energy of 0.52–2.6 J and a productivity of 1.0–2.0 cm2/min, while the discharge energy and productivity are chosen such that the surface roughness decreases by ≅ 3–4 times. At the second stage aluminizing for both options, when using a consistent substance that contains aluminium powder or aluminium powder and graphite powder, the microhardness of the ‘white layer’ and the diffusion zone are increased (to a greater degree when graphite is present in the consistent substance), the surface roughness is decreased, and the integrity of the coating is of 100%. Before practical implementation, it is recommended to carry out the aluminizing process according to the first option at the discharge energy Wp = 4.6–6.8 J, using a consistent substance containing aluminium powder and graphite powder at the second stage.

Keywords:
electrospark alloying,aluminizing,productivity,surface layer,quality,structure,roughness,microhardness,thickness of the white layer,coating continuity

Abstract:
Przedstawiono wyniki oceny diagnostycznej posadzki przemysłowej przy wykorzystaniu metodyki ilościowej oceny mikrostruktury betonu. Objawy uszkodzeń obejmowały pylenie powierzchniowe i delaminację warstwy utwardzonej. Przeprowadzono analizę petrograficzną składu betonu w próbkach-odwiertach. Zaobserwowano nadmierne napowietrzenie betonu, gromadzenie się porów powietrznych i występowanie ukierunkowanych spękań, miejscową zmienność składu fazowego produktów hydratacji cementu, w tym występowanie obszarów o intensywnej karbonatyzacji, co wpływało na przedwczesne uszkodzenia powierzchniowe.
Diagnostic assessment of industrial floor using the methodology of quantitative evaluation of concrete microstructure is presented. Symptoms of damage included surface dusting and delamination of the top layer. A petrographic analysis of the concrete composition in core specimens was carried out. Excessive air content, accumulation of air voids and the occurrence of oriented cracks, local variability of the phase composition of cement hydration products, including the occurrence of carbonated areas were observed and associated with the premature surface damage.

Keywords:
delaminacja, mikroskopia ilościowa, porowatość, posadzki betonowe, utwardzenie powierzchniowe, delamination, quantitative microscopy, porosity, concrete floors, surface hardening

Keywords:
sztuczna inteligencja,globalne zagrożenia,interfejs mózg-komputer,potrzeba globalnych regulacji

Keywords:
współpraca,mobilność studentów,synergia wyników badań,wspólne dyplomy

Abstract:
This study presents a novel, straightforward approach for synthesizing graphitic carbon nitrides (g-C3N4, g-CN) from melamine, requiring merely 30 min of thermal holding at temperatures ranging from 400 to 550 °C in an atmosphere comprising either nitrogen or air. Elemental analysis, X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), diffuse reflectance (UV–Vis DRS), photoluminescence (PL) spectroscopy and scanning electron microscopy (SEM) were employed to assess the quality of the as-prepared powders. Furthermore, theoretical calculations utilizing the Density Functional Theory (DFT) method were conducted to reinforce the experimental findings of the research. A further investigation of the thermal stability of the selected sample was conducted using a unique combination of thermogravimetry–coupled with differential scanning calorimetry, quadrupole mass spectrometry (TG-DSC-MS) and advanced temperature-programmed desorption (TPD) analyzes. The current study focuses on the effect of synthesis conditions (temperature and nitrogen/air environment) on the structure, morphology, and photocatalytic performance of g-C3N4 compounds synthesized using this approach. The g-C3N4-based materials were examined as potential photocatalysts using the acid orange 7 (AO7) photodegradation methodology. To enable comparison of the photodegradation experiments, two separate lamps with wavelengths of 360 nm (UV light) and 420 nm (VIS light) were utilized. The primary objective was to present a novel method for the synthesis of g-C3N4-based materials. This was achieved by demonstrating that organic composites generated at lower temperatures have the best photocatalytic capabilities. Furthermore, the approach to achieving high-quality photocatalysts was shown to be cost-effective, environmentally friendly, and scalable.

Keywords:
AgNPs, Fe3O4, bifunctional, SERS, NSAIDS

Abstract:
Arm-Z is a concept of a hyper-redundant manipulator based on linearly joined sequence of congruent units. Each unit has only one degree of freedom (1-DOF) - the twist relative to the previous unit.
This paper presents the approach to design of modular robotic manipulator based on computer simulations. The approach is rather standard nowadays, however, it is applied to rather unique robotic system. The
CAD model of the module structure for a manipulator with 6 degrees of freedom and respective Denavit-Hartenberg notation are presented. Simulink - a MATLAB-based graphical programming environment was
used to determine the torques of individual modules. The results of three simulations are presented and discussed. Finally, based on critical observations, the drive and gear for the module of Arm-Z system were selected.

Keywords:
Simulation,Robotic arm,Manipulator,Arm-Z,MATLAB Simulink

Abstract:
This paper presents the design and construction process of the Arm-Z manipulator, which represents the concept of a hyper-redundant manipulator based on a connected sequence of identical modules. Each
module provides a single degree of freedom (1-DOF), specifically a twist relative to the previous module. The uniformity of the modules gives Arm-Z the potential to be cost-effective and robust. Standardized modules allow for mass production and can be easily replaced in case of failure. This paper discusses each stage of the design process from mechanical perspective, including: module’s geometry, simulation based on Denavit-Hartenberg parameters, and manufacturing process. The section covering work on the electrical system discusses issues such as selection of: motors, power supply, protections, and the network’s topology connecting EPOS controllers.

Keywords:
Robotic arm, Manipulator, Hyperredundant, Arm-Z, Extremely Modular System

Abstract:
Multiple bifurcations due to symmetry are often encountered when analyzing nonlinear motifs of nano-mechanics or structures with axial multiple symmetry. The location of multiple bifurcation points and bifurcation path tracing become problems in numerical analysis. In this paper, as a solution to this problem, the a priori information of group-theoretic bifurcation theory is applied. By utilizing the irreducible representation of the dihedral group, we propose to represent the initial imperfection vectors according to the difference in symmetry of the structural system. A part of the tangent stiffness matrix is corrected by coordinate transformations, and
the modified stiffness method is proposed to separate the multiple bifurcation points to a single point in the direction of the bifurcation path. As a numerical analysis example, a bifurcation analysis of a fullerene structure is performed to demonstrate the feasibility of the presented method.

Keywords:
Graph-theory, Bifurcation, Imperfection, Fulerene, Dihedral group

Abstract:
This contribution considers the problem of topology optimization of modular structures. A bionic trunk-like robotic “Arm-Z” manipulator is considered. The manipulator is modular, that is, it is composed of a sequence of identical modules. In geometric terms, each module is essentially an obliquely cut section of an elliptical pipe, so in the cutting plane it forms a circle. With respect to the previous module, it has a single degree of freedom: the relative twist. Therefore, the total number of the degrees of freedom of the entire manipulator equals the number of its modules. Such a manipulator belongs to the family of Extremely Modular Systems. The advantages of such systems are the economization (due to the possible mass production of modules) and robustness (replacement of a failed module instead of a complex repair).

Keywords:
Topology optimization, Modular manipulator, Multiple loadings, Geometric transformations, Kinematics, Stress constraints.

Abstract:
The aim of this research was to investigate an effect of low temperature on the mechanical properties and microstructure of 6061-T6 aluminium alloy (AA6061-T6) subjected to dynamic loading. The specimens were subjected to dynamic compression at a low temperature of -80°C in a range of strain rates from 1.25×103 1/s to 3.4 ×103 1/s to compare their mechanical responses. The deformation mechanisms were analysed through EBSD observations during which dynamic recovery, was found as the dominant one. Furthermore, microstructural analysis indicated that deformation under high strain rate conditions and temperature of -80°C enables to keep the constant initial grain size of the material after the loading applied.

Keywords:
Split Hopkinson Pressure Bar (SHPB), low temperature, AA6061, microstructure, EBSD

Abstract:
The Laser Powder Bed Fusion Melting (LPBF-M) method was used to additively manufacture stainless steel 316L tubes in three different orientations. The yield surface approach was implemented to assess the variation of mechanical properties within the as-built specimens. Yield surfaces were determined for each build orientation based on the definition of yield stress for 0.005% plastic offset strain. The initial yield surfaces obtained for the as-built material exhibit anisotropic behaviour, possibly resulting from the preferred grain orientation developed during LPBF-M processing.

Abstract:
This paper presents an analysis of various technologies, including such as aluminization, cementation, nitriding, and nitrocementation, to increase the quality parameters of surface layers of parts, performed by electrospark alloying (ESA) and by additional saturation of surfaces with alloying elements from special technological environments (STE). During aluminization, the thickness of the "white" layer and the diffusion zone, as well as the microhardness, coating continuity and roughness of the surface increased as the discharge energy (Wp) increased. The layer consists of iron-aluminium intermetallics and free aluminium. It has been proposed to perform the ESA process with the same electrode (aluminium), but at lower energies, in order to reduce the surface roughness and obtain continuous coatings. The comparative study of the parameters of the quality of the layers after the traditional cementation - ESA with carbon electrode (CESA) and after the proposed one has shown that after the treatment of the surface with the use of the proposed technology, the roughness of the surface decreases. Simultaneously, the continuity of the doped layer increases up to 100%, the depth of the carbon diffusion zone increases up to 80 µm, and the microhardness and "white" layer thickness increase to 9932 MPa and 230 µm, respectively. The analysis of the structure-forming characteristics of the surface layers of carbon steel after ESA nitriding and nitrocarburising using STE has shown that the layer structures obtained consist of the following three areas, such as the non-etchable "white" layer, the modified diffusion zone and the substrate. Thickness, microhardness of the coating zones, integrity of the "white" layer, and surface roughness also increase as the discharge energy increases.

Keywords:
Electrodes, Hardness, Metallurgy, Surface hardening

Abstract:
This contribution presents a semi-active control technique intended for mitigation of structural vibrations. The control law is derived in a repeated trial-and-error interaction between the control agent and a simulated environment. The experience-based training approach is used which is the defining feature of the machine learning techniques of reinforcement learning (RL), implemented here using the framework provided by Deep Q Learning (DQN). The involved artificial neural network not only determines the control action, but additionally identifies structural damages, which is a nontrivial task due to the nonlinearity of the control. This requires a specific multi-head architecture, which allows the network to be damage-aware, and a specific training procedure, where the memory pool preserved for the RL stage of experience replay is populated with not only the observations, control actions, and rewards, but also with the momentary status of structural damage. Such an approach can be used to explicitly promote the damage-awareness of the control agent. The proposed technique is tested and verified in a numerical example of a shear-type building model subjected to a random seismic-type excitation. A tuned mass damper (TMD) with a controllable level of viscous damping is used to implement the semi-active actuation, and the optimally tuned classical TMD provides the reference response.

Keywords:
semi-active control, tuned mass damper (TMD), reinforcement learning, damage identification

Abstract:
W artykule autorzy omawiają duże modele językowe (ang. Large Language Models, LLMs) w kontekście zagrożeń bezpieczeństwa wynikających z funkcji i dostępności tych modeli. Mimo że pod względem zastosowań LLMs wydają się podobne do wyszukiwarek internetowych, to generują nowe zagrożenia związane z dostarczaniem przez nie przestępcy i terroryście podstawowych umiejętności analitycznych i programistycznych. Autorzy dowodzą, że dostępne modele językowe nie tylko zmniejszają bariery finansowe dla rożnych działań przestępczych, lecz także obniżają poziom wiedzy specjalistycznej i zaangażowania wymagany od jednostek lub małych grup do popełniania przestępstw, w tym aktów terrorystycznych. Z drugiej strony możliwości tych modeli mogą wykorzystać również organy ścigania, aby być przygotowanymi na pojawiające się zagrożenia.

Keywords:
Large Language Models, bezpieczeństwo, cyberprzestępczość, terroryzm dżihadystyczny, sztuczna inteligencja

Abstract:
Over the past 20 years, there has been a dramatic increase in the incidence of various cancers. The increased detection of various malignancies and their effective treatment requires the search for new approaches in anti-cancer therapy. One option is the use of nanomaterials and nanocomposites based on them to form a platform for simultaneous imaging, such as by nuclear magnetic resonance, and treatment by local drug release and temperature elevation directly in tumor tissues [1]. Here, we present results on the colloidal suspension based on superparamagnetic iron-oxide-based nanoparticles and hydroxyapatites as the matrix for the local anticancer drug release. The studies were focused on the optimization of the synthesis experimental composition, characterization of obtained material, and stability in aqueous solutions like PBS to be used in magnetic hyperthermia to generate heat locally and enhance the drug delivery. Core-shell particles were synthesized using a two-step wet co-precipitation method and stabilized with biocompatible organic molecules to produce stable colloidal suspension [2,3]. The heat generation effectiveness was determined using magnetic hyperthermia (MH), where the conditions to reach therapeutic temperature of the suspension in the constant and pulsed amplitude of alternating magnetic field (AMF) were optimized.

Abstract:
Environmental pollution caused by anthropogenic activities is one of the biggest challenges globally.
One of the largest groups of compounds polluting the aquatic environment are antibiotics, dyes, and pigments, which are mainly released from manufacturing waste from textile, wood, and pharmaceutical industries. Such chemicals not only affect animals living in aquatic systems, but also cause a range of health problems in humans, increasing the risk of cancer and disrupting the endocrine and immune systems. In this work, we focus on wastewater treatment solutions based on magnetic nanomaterials that can effectively purify water through adsorption and can also act as a photocatalyst that can degrade pollutants. The proposed nanomaterials and their composites offer non-toxicity, high surface area and magnetic properties that can be easily removed from solution after wastewater treatment with magnets. The proposed nanomaterials, in particular superparamagnetic iron oxide nanoparticles (SPIONs) and their composites with spent biomass and pyrolyzed biomass, offer high efficiency in water treatment, rapid separation from treated solutions and reuse. Furthermore, SPIONs can also be combined with a wide variety of metal ions, making them a promising platform for the removal of heavy metal ions from contaminated solutions, such as hydrometallurgical waste. The work will discuss the synthesis and characterization as well as the model of adsorption and mechanism of pollutants removal.

Keywords:
Supercapacitors, Polymer gel electrolyte, Host polymer, ELDCs

Keywords:
Supercapacitors, Activated Carbon, Polymer gel electrolyte, Surface modification

Keywords:
Supercapacitors, Polymer gel electrolyte, Host polymer, ELDCs

Abstract:
This contribution applies the machine learning technique of reinforcement learning for simultaneous damage detection and control of structures. The proposed system consists of two components. The control component is responsible for semi-active mitigation of vibrations. The control law is determined experimentally in a trial-and-error interaction with a simulated environment. The process is data-driven: the control agent iteratively improves its control law based on the observed results of past control actions. The robustness relies on the accuracy of the structural model used for training. The control efficiency can decrease if the physical structure is damaged and diverges from the model, that is, when effective control may be most required. Thus, the second component of the proposed system monitors the structure to detect damages and inform the control component. The approach is tested in a numerical experiment of a shear-building under random seismic-type excitation. A semi-active tuned mass damper (TMD) is used as an actuator, and a classical TMD serves as a reference.

Keywords:
semi-active control, structural control, structural monitoring, reinforcement learning, machine learning

Abstract:
Classical approaches to attenuation of vibrations usually aim at dissipation or absorption of the vibration energy in especially designed devices mounted to the structure. A less common approach but recognised as very effective is to induce mechanisms of transferring the vibration energy associated with low-frequency modes into higher-order vibration modes, where it is quickly dissipated by material damping (in structural volume). In the present work, a novel semi-active modal control methodology is proposed for precise control of mechanical energy transfer between vibration modes by means of lockable joints. Moreover, this control strategy is well-suited also for energy harvesting purposes. Energy of the currently induced vibration modes can be transferred into a preselected structural vibration mode that is tuned with an energy harvester. The proposed control strategy is verified numerically, whereas its experimental validation is shown in the accompanying article within the present proceedings.

Abstract:
In this work an experimental study is presented aiming at demonstration of a controlled modal energy transfer concept in frame structures equipped with semi-active members. The proposed semi-active members – lockable joints – allow for local modification of the frame’s stiffness. The objective of the introduced control approach is to provide mechanical energy transfer between particular eigenmodes. A demonstrator has been fabricated for the purpose of the investigation consisting of a double beam frame structure in a cantilever configuration, which is equipped with the semi-active members. The investigated control algorithm employs two types of input signals: local velocity of the structure and local strain of the frame. As a result, a verification of the system effectiveness has been revealed in a variety of frequency ranges. The excitation bandwidth has been appropriately suited to the particular tested cases. The experimentally obtained results confirmed a possibility of the energy transfers between particular structural eigenmodes.

Keywords:
Shape memory alloys, Branched microstructures, Energy minimization, Continuum framework

Keywords:
AgriculturalWaste, Animal Origin Fibres, Cement-BasedMaterials, Microstructure, Mechanical Properties

Abstract:
Automation in Construction is currently one of the main new directions in Ł-PIAP. Our department is equipped with state-of-the-art devices, such as: an industrial 3D printer with a workspace of 15/5/5 m, capable of printing with concrete or extruded polystyrene and milling; a mobile 3D printer with a workspace of 5/3/3 m with the same capabilities; an industrial KUKA 500 robot with various designated end-effectors; a Wire Arc Additive Manufacturing (WAAM) multi-dimensional device using alloy and steel, etc. Here we present our ongoing projects and prospects that have the potential to revolutionize the construction industry by setting new standards for efficiency, precision and safety.

Abstract:
Extremely Modular System (EMS) is a relatively new concept introduced a few years ago. It represents a new approach to the design of engineering structures and architectural objects where assembly of congruent units allows for the creation of free-form shapes. The main difference from the traditional modular systems used in engineering, is the emphasis of the minimal diversity of types of modules, ideally - just one. This is why these system are called "extremely" modular. One of the most natural areas for use of EMSs are deployable structures. This paper presents rigid body folding mechanisms for two selected EMSs: Pipe-Z - a parametric system comprised of one type of module allowing for creation of three-dimensional knots, and Truss-Z - a modular system for creating free-form ramps and ramp networks among any number of terminals.

Keywords:
Extremely Modular System, Deployable Structure, Free-form. Pipe-Z, Truss-Z

Abstract:
Artificial intelligence (AI) is penetrating higher medical education; however, its adoption remains low. A PRISMA-S search of the Web of Science database from 2020 to 2024, utilizing the search terms “artificial intelligence,” “medicine,” “education,” and “ethics,” reveals this trend. Four key areas of AI application in medical education are examined for their potential benefits: Educational support (such as personalized distance education), radiology (diagnostics), virtual reality (VR) (visualization and simulations), and generative text engines (GenText), such as ChatGPT (from the production of notes to syllabus design). However, significant ethical risks accompany AI adoption, and specific concerns are linked to each of these four areas. While AI is recognized as an important support tool in medical education, its slow integration hampers learning and diminishes student motivation, as evidenced by the challenges in implementing VR. In radiology, data-intensive training is hindered by poor connectivity, particularly affecting learners in developing countries. Ethical risks, such as bias in datasets (whether intentional or unintentional), need to be highlighted within educational programs. Students must be informed of the possible motivation behind the introduction of social and political bias in datasets, as well as the profit motive. Finally, the ethical risks accompanying the use of GenText are discussed, ranging from student reliance on instant text generation for assignments, which can hinder the development of critical thinking skills, to the potential danger of relying on AI-generated learning and treatment plans without sufficient human moderation.

Keywords:
Artificial intelligence, Metaverse, Medical education, Education system, Ethics

Abstract:
Graph Neural Networks (GNNs) are recognized as potent tools for processing real-world data organized in graph structures. Especially inductive GNNs, which allow for the processing of graph-structured data without relying on predefined graph structures, are becoming increasingly important in a wide range of applications. As such these networks become attractive targets for model-stealing attacks where an adversary seeks to replicate the functionality of the targeted network. Significant efforts have been devoted
to developing model-stealing attacks that extract models trained on images and texts. However, little attention has been given to stealing GNNs trained on graph data. This paper identifies a new method of performing unsupervised model-stealing attacks against inductive GNNs, utilizing graph contrastive learning and spectral graph augmentations to efficiently extract information from the targeted model. The new type of attack is thoroughly evaluated on six datasets and the results show that our approach outperforms the current state-of-the-art by Shen et al. (2021). In particular, our attack surpasses the baseline across all benchmarks, attaining superior fidelity and downstream accuracy of the stolen model while necessitating fewer queries directed toward the target model.

Abstract:
The article presents research on finishing treatment applied to components made of Inconel through 3D printing by Laser Powder Bed Fusion method. Vibration-abrasive machining was carried out using a supporting fluid and various shapes of abrasive. The effects of the processing conditions were analysed based on the surface roughness of the samples and mass loss. The obtained collective results were subjected to comparative analysis with the effects of vibratory-abrasive processing without the use of a processing fluid, as presented in the article. The research has shown that using vibration-abrasive processing, it is possible to reduce the height of surface irregularities by more than three times after four hours of treatment. The intensity of processing was the highest in the first hour of the process. The lowest roughness heights Ra = 1.8 μm were obtained using ceramic balls in the presence of a supporting fluid.

Keywords:
vibration-abrasive processing, IN939, roughness, additive manufacturing, 3D printing post-processing

Abstract:
Symulacje komputerowe odgrywają coraz większą rolę w planowaniu, przygotowaniu oraz interpretacji badań ultradźwiękowych. W artykule opisano podstawowe założenia teoretyczne oraz funkcjonalności programu SymUT rozwijanego w pracowni badań nieniszczących IPPT PAN. W celu ilustracji możliwości programu pokazano proste przykłady jego zastosowania do obliczania rozkładów pola ultradźwiękowego głowic ultradźwiękowych oraz obwiedni echa wad modelowych. Opisano zasady wykorzystania programu do projektowania głowic ultradźwiękowych oraz przygotowania procedur badawczych
Computer simulations are playing an increasingly important role in planning, preparation and interpretation of ultrasonic testing. The article describes the basic theoretical assumptions and functionalities of the SymUT software developed in the non-destructive testing laboratory of IPPT PAN. In order to illustrate its capabilities, simple examples of its use for calculation of the ultrasonic field of ultrasonic probes as well as the echo envelopes from model defects are shown. The principles of using the program for designing of ultrasonic probes and preparing testing procedures are described

Keywords:
badania ultradźwiękowe, defektoskopia ultradźwiękowa, wiązka ultradźwiękowa, wady materiałowe, symulacje badań ultradźwiękowych, ultrasonic testing, ultrasonic flaw detection, ultrasonic beam, material defects, ultrasonic testing simulations, radar testing, electromagnetic testing

Abstract:
The effect of adjacent threading dislocation at the edge of polar GaN/AlN quantum dot was widely discussed in the literature, see e.g. [1]. Anyway, development of growth techniques for the III-nitrides is moving towards semipolar or even nonpolar orientations, where more efficient radiative recombination is expected due to less significant quantum confinement Stark effect and elimination of spontaneous polarisation. New growth orientations entails entirely new geometry of quantum structures, what calls into question already done analyzes carried out for polar setup. First off all, there are only a few experimental reports showing the real geometry of semipolar and nonpolar quantum dots which differs significantly from well known truncated hexagonal pyramid shape, see e.g. [2]. Secondly, there is no clear information about the geometric relation of the dislocation line and the quantum dot as it was clearly presented in the polar case. However, such relation definitely exists as it is well documented that its dislocation density is much higher compared to crystals grown in the polar regime. Finally, the possible effect of charged dislocation line may additionally alter the optoelectronic properties of the quantum dot [3].

In this work, finite element method is used to determine how the threading dislocation affects semipolar and nonpolar quantum dots and alternates its build-in elastic and electric fields, so in this way modify band-to-band transition energy for the recombining pair of carriers. Threading dislocation, modeled by use of classical continuum dislocation theory via polynomial approximation for distortion field, generates axisymmetric elastic and electric fields. Coupled fields around dislocation line affect neighbouring quantum dot with its build-in fields related to lattice mismatch between GaN dot and AlN matrix and in a limited extent to spontaneous polarisation. Additionally, electric charge localised along the dislocation line is taken into account, and generates extra negative potential field affecting close surroundings of the threading dislocation. Two common types of threading dislocations for III-nitride epitaxial layers are considered: perfect edge- and perfect screw-type dislocation.

It is demonstrated that local elastic and electric fields around threading dislocation together with the presence of an electric charge along dislocation line affect local piezoelectric field build-in the quantum dot, creates geometrical shift of the carrier localization regions, and reduce band-to-band transition energy.

REFERENCES
[1] Rouviere, P.J.L., et al., Appl. Phys. Lett. 75, 1999, 2632.
[2] Dimitrakopulos, G.P., et al., J. Appl. Phys. 108(10), 2010, 104304.
[3] Jurczak, G., Dłużewski, P., Phys. E: Low-Dimens. Syst. Nanostructures, 95, 2018, pp. 11-15.

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

Abstract:

This study deals with topology optimization of spatial robotic manipulator, the geometry of which was
proposed initially in [1]. The manipulator consists of serially connected modules in a form of a
cylinder cut at a certain angle at its ends. The manipulator constructed in this way allows for relative
rotation of adjacent modules, which gives one degree of freedom per module. The operation of overall
robotic system resembles the elephant trunk manipulator. Previous research involved the possible
kinematic transformations of the manipulator [2], but not its structural optimization [3]. However,
structural design of the involved modules is a challenging task, as the process has to take into account
the current configuration of the module along the manipulator, which results in variable internal force.
It leads to optimization problem under multiple loading conditions with a significantly large number of
loads. This study considers optimal topology of such a modular manipulator structure. Due to the large
variety of possible load conditions, the initial analysis involves a 3D model of the structure with a
continuous set of possible arrangements of individual modules. An additional constraint imposed on
the solution will take into account the symmetry of the optimal topology of a single module, which is
dictated by manufacturing considerations.

Keywords:
optimal topology, modular systems, engineering software

Abstract:
This presentation considers a semi-active control method aimed at the reduction of structural vibrations in the presence of unknown structural damages. The control algorithm is developed using reinforcement learning [1], a machine learning technique characterized by an iterative trial-and-error interaction of the control agent with the controlled structure. A quasi-optimal control law is derived by observing and learning from the collected interaction experience. By being data-driven, this strategy bypasses the need for an analytical derivation of optimal control, which can be challenging in semi-active and nonlinear control systems [2]. The approach of double Deep Q Learning (DQN) with experience replay is used. It builds upon earlier results [3], but here the aim here is to promote control robustness in the presence of unknown structural damages. The control algorithm is ultimately encoded in the form of a trained artificial neural network with a custom architecture that involves a dedicated damage-identification branch.
The effectiveness of the approach is demonstrated using a numerical model of a structure subjected to a seismic-type random excitation. A semi-active tuned mass damper (TMD) is employed as the actuator, and the control signal affects its viscous damping properties. The reference baseline is provided by the optimally tuned, classical passive TMD.

Keywords:
Structural control, Semi-active control, Structural health monitoring (SHM), Reinforcement learning, Machine learning

Abstract:
Atomistic models of dislocations in crystalline structures are often obtained by means of elastic-
plastic relaxation of a perfect crystal lattice subjected to external loading. Another method is based
on inserting of single dislocations into the perfect lattice. In this case the analytic formulas for the
glide of a single dislocation in elastic continuum are used. The methods mentioned above do not
give the possibility for emerging atomistic model of an arbitrary chosen network of dislocations. This
problem concerns many sets of dislocations observed by means of high resolution transmission
electron microscopy. In this presentation we introduce a deterministic method for obtaining atomistic
models of dislocations. The method is based on the use of symbolic algebra of elemental lattice
distortion tensor fields. Contrary to the linear strain and rotation measures, the lattice distortion
tensor is the correct measure of finite deformation. Thus, on the basis of distortion field, many
different tensor fields of finite strains and rotations can be determined uniquely. This enables
generation of atomistic models in terms of finite deformation approach [1,2]. The method presented
here links: (i) the analytic formulas for lattice distortions derived from the linear theory of dislocations,
(ii) the finite deformation algebra of distortion fields, and (iii) the atom-by-atom reconstruction of
dislocations including their core structures. This method has been implemented in a visual editor of
dislocations. Configurations of atoms obtained in this way satisfy the stress equilibrium equations in
terms of linear elasticity. On the other hand, the spatial Burgers vectors of dislocations are stretched
and rotated to each other according to the finite deformation theory. The resultant net of atoms can
used as input data to ab-initio and/or molecular dynamics programs to find a low energy configuration
corresponding to a given interatomic potential.

[1] Łażewski J., Jochym P.T., Piekarz P., Sternik M., Parlinski K., Cholewiński J., Dłużewski P.,
Krukowski S., J. Mater. Sci. 54, 10737-10745, 2019.
[2] Cholewiński J., Maździarz M., Jurczak G., Dłużewski P., Int. J. Multiscale Comp. Eng. 9, 411-421,
2014.

Keywords:
Ternary transition metal diboride thin films, Mechanical properties, HiPIMS/DC magnetron sputtering, wear resistance and adhesion, DFT Methods

Keywords:
Cubic Crystal Structure, Deformable Discrete Element Method, Numerical Modeling, Numerical Homogenization, Elastic Properties

Abstract:
The study introduces a methodology that integrates a novel velocity estimation approach with the Particle Filter for accurately estimating the position of an object navigating within a magnetic anomaly field. To accurately determine position in GPS-denied environments, the acceleration measurements obtained from the Inertial Measurement Unit are augmented with magnetic field measurements and a previously designed magnetic anomaly map. Then, Bayesian statistics are employed to fuse information from the Inertial Measurement Unit and magnetometer, enabling accurate estimation of the object's velocity. The estimated velocity serves as input for the propagation model within the Particle Filter, which accurately predicts the object's position. This study showcases the efficacy of Bayesian-based velocity estimation in enhancing the classical Particle Filter approach, resulting in an approximate 40-55% reduction in the mean trajectory error. This refined methodology holds promise for applications across diverse domains, including GPS-independent navigation for vehicles