Latest Publications

Abstract:
This work analyzes the deformable discrete element method (DDEM) as a tool for modeling linear-elastic properties of single crystals of cubic symmetry. DDEM is an extension of the standard DEM, in which particles deform under stress. Through this deformation, an interaction between two particles becomes dependent on other interactions in which these particles participate. This nonlocal characteristic gives DDEM an enhanced ability to model solid materials. The present analysis is mainly focused on the simple cubic (SC) pattern of identical spherical DDEM particles bonded by cohesion, in the small-strain regime. It is shown that the majority of crystals of cubic symmetry can be modeled by this pattern in a numerically stable way. When simple geometric patterns other than SC are considered, it is argued that DDEM is able to represent the linear-elastic properties of all cubic crystals satisfying the Born stability criteria. This is an improvement upon the standard DEM, in which many cubic materials of high anisotropy cannot be modeled using simple particle arrangements. A number of numerical tests, complemented by analytical investigations, are performed to validate the approach and estimate its accuracy.

Keywords:
Discrete element method, Deformable particles, Cubic anisotropy, Linear elasticity, Crystal, NiAl

Abstract:
This study investigates the influence of crystallographic orientation on fracture behavior and the resulting mechanical anisotropy in a alloy crystal containing radiation-induced defects, using molecular dynamics (MD) simulations. Crack propagation is analyzed in irradiated samples with three selected high-symmetry crystallographic orientations to show how radiation-induced defects modify local deformation mechanisms and amplify mechanical anisotropy. The investigation focuses on the anisotropic nature of the ductile-to-brittle transition (DBT) driven by radiation-induced defects by simulating fracture behavior under tensile loading. Fracture resistance is quantitatively evaluated using a traction–separation (T–S) approach to extract the atomic-scale fracture energy under realistic defect conditions. The results reveal a strong crystallographic orientation dependence in the evolution of deformation and fracture behavior during DBT. The crystal lattice orientation governs dislocation activity and defect interactions, which in turn regulate local plasticity mechanisms, strain localization, slip system activation, and fracture resistance, thereby driving the development and enhancement of mechanical anisotropy in irradiated materials. It is further shown that radiation-induced embrittlement cannot be explained solely by defect accumulation, but rather by orientation-sensitive interactions among dislocations, defects, and fracture process zones. A key novelty of this work lies in integrating radiation-induced defect evolution with orientation-dependent fracture within an atomistic T–S analysis, enabling quantitative assessment of atomic-scale fracture resistance under realistic defect conditions.

Keywords:
Crack propagation, Radiation defects, MD simulations, Cr-rich alloy, T–S law, Atomic-scale fracture energy

Abstract:
This paper proposes a novel velocity estimation technique and integrates it with the particle filter to achieve precise positioning of an object moving within a magnetic anomaly field. To estimate the position in GNSS-denied environments, acceleration measurements acquired from the inertial measurement unit are combined with magnetic field measurements and a magnetic anomaly map. The magnetic field measurements are utilized at two levels. First, Bayesian data fusion is applied to process the rate of change of the magnetic field along the object’s trajectory in order to refine the velocity acquired from the inertial measurement unit. This refined velocity estimation serves as an input for the propagation model of the particle filter, which subsequently uses the magnetic field measurement and the magnetic anomaly map to estimate the object’s position. The proposed method was tested for navigating an unmanned aerial vehicle (UAV) using the ArduPilot simulator across a variety of realistic scenarios. The results demonstrate the efficacy of Bayesian-based velocity estimation in enhancing the classical particle filter approach, leading to a substantial reduction in the mean trajectory error. The developed method improves GNSS-independent positioning and navigation and holds promise for applications in various aircraft and robotic systems.

Keywords:
Magnetic anomaly navigation, Particle Filter, Bayesian inference, Unmanned aerial vehicle, Sensor fusion

Abstract:
Mode decomposition is a widely adopted data-driven strategy in modal analysis. It is an essential tool for identifying modal parameters and understanding the dynamic behavior of systems. However, existing mode decomposition methods often suffer from modal aliasing and lack clear physical interpretability. This study introduces a time-domain constrained mode decomposition method that employs a linear combination of free response signals to extract clean intrinsic mode functions and accurate modal parameters. A constraint matrix, derived from the autoregressive model of single-mode signals, is used to form a characteristic constraint equation and determine the decomposition coefficients. The influence of the autoregressive calculation time interval on the stability of Prony polynomial solutions is analyzed to determine the order and form of the constraint filter. Furthermore, combining the constraint filter with a low-pass FIR filter improves the noise robustness of the proposed method. For modal identification, the preliminary eigenvalues are determined using the Yule-Walker equation, followed by iterative elimination of spurious eigenvalues and refinement through the application of multi-objective constraint filters. Ultimately, the proposed method enables accurate, adaptive, and physically interpretable signal decomposition and modal parameter identification. Statistical results from numerical simulations validate its robustness to noise and stability, while comparisons with other mode decomposition techniques confirm that it achieves complete signal decomposition. Experimental verification using a frame test model further demonstrates the accuracy of the proposed method in modal identification.

Keywords:
Mode decomposition, Autoregressive model, Modal identification, Signal processing, Constraint filter

Abstract:
Molten carbonate electrolysis (MCE) is a promising high-temperature route to upgrade CO2-rich biogas into a higher heating value fuel while enabling CO2 separation and utilization. This paper proposes and experimentally evaluates a biogas upgrading concept based on a three-cell MCE stack operated on synthetic biogas mixtures. The stack is fed with CH4/CO2/H2O at the cathode and air at the anode and powered by external electricity, representative of surplus renewable power. Electrochemical performance is assessed through current-voltage characteristics and steady-state operation at selected current densities, while product-gas compositions are quantified by gas chromatography. The results demonstrate stable stack operation on biogas-type feeds and show that MCE can simultaneously remove CO2 and enrich the cathodic stream in H2 (and CO), thereby increasing the lower heating value compared with the raw biogas. From the measured data, key process indicators such as CO2 removal degree, gas upgrading factor, and specific electrical energy consumption are derived and discussed. The study establishes molten carbonate electrolysis as a viable and flexible option for biogas upgrading and valorization, particularly in systems coupled to intermittent renewable electricity. Unlike conventional separation-based routes (water scrubbing, PSA, membranes) that vent the captured CO2, or SOE-based power-to-methane systems that require a separate methanation reactor, MCE simultaneously removes CO2 and generates H2/CO within a single high-temperature unit. The present results provide the first experimental evidence that a multi-cell MCE stack can serve as a viable and load-flexible pathway for biogas upgrading and valorization, particularly when coupled with intermittent renewable electricity.

Keywords:
Molten carbonate electrolysis, Biogas upgrading, CO2 separation, High-temperature electrochemical conversion, Syngas and hydrogen enrichment

Abstract:
β-sitosterol is the most abundant phytosterol, but it exhibits low stability and bioaccessibility, requiring effective delivery systems. In this study, nine β-sitosterol-loaded microspheres were produced using edible insect proteins (T. molitor, A. domesticus, L. migratoria) and κ-, ι-, or λ-carrageenan via complex coacervation and spray-drying. The resulting spherical microcapsules (<15 μm) showed strong protein-polysaccharide interactions, particularly with κ- and ι-carrageenan, which induced β-sheet-rich structures and improved stability. λ-carrageenan produced more flexible, α-helical microspheres with lower oxidative stability. Lipid peroxidation was inhibited by up to 95%, although λ-CG variants exhibited 2–3× higher oxidation. HS-SPME/GC–MS confirmed the suppression of volatile oxidation markers. β-sitosterol retention reached 66–95%, largely depending on carrageenan type. In vitro digestion showed low oral (9–15%) and moderate gastric release (28–39%), with the highest release in the intestinal phase (38–54%), resulting in overall bioaccessibility exceeding 85% for all formulations.

Keywords:
Edible insect protein, Carrageenans, β-Sitosterol, Microencapsulation, Oxidative stability, Bioaccessibility

Abstract:
Discontinuous plastic flow (DPF) in austenitic stainless steels at cryogenic temperatures is typically identified by serrated stress–strain responses. Here, acoustic emission (AE) is used to probe deformation during uniaxial tensile tests of 304, 316L, and N50 steels at 4 K. Pronounced AE activity is detected well before stress drops, revealing discrete precursor events. The results show that DPF is preceded by progressive microstructural reorganization and establish AE as a sensitive tool for identifying plastic instability.

Abstract:
This paper investigates the dynamic behaviour of a thick Gao beam subjected to high-velocity inertial moving loads and substantial axial compressive forces. This approach addresses a significant gap by combining geometric nonlinearity, transverse shear deformation, and complete inertial effects (including Coriolis and centrifugal forces).
The mathematical model consists of two strongly coupled nonlinear hyperbolic partial differential equations, solved using the finite element method with space-time integration. Key findings include: (1) nonlinearity produces substantial geometric stiffening effects, with deflections decreasing by factors of 2-3 compared to linear models; (2) supercritical axial compression induces snap-through phenomena and bifurcation between equilibrium states; (3) under combined compression and moving loads, beam deflections are primarily governed by axial force magnitude rather than load weight, with multiple passages producing non-repeating response patterns; (4) maximum accelerations occur neither at mid-span nor at support entry, remaining relatively insensitive to transit velocity. The results indicate a strong detuning between the beam oscillations and the load transition cycles, especially at higher velocities. These findings have important implications for railway bridge design and structures experiencing simultaneous thermal stresses and dynamic vehicular loads, where simplified linear models may significantly underestimate dynamic effects.

Keywords:
Structural dynamics, Extended Gao beam, Moving mass, Inertial load, Non-linear dynamics, Shear deformation

Abstract:
Recent advances in single-cell technologies have revealed the dynamic and heterogeneous nature of host-pathogen interactions at the single-cell level. This review explores how cellular variability—both within clonal bacterial populations and among genetically identical host cells—gives rise to distinct infection outcomes, from pathogen clearance to persistence across multiple biological scales, from single cells to tissues and the whole organism. We highlight the conceptual and technological progress that has enabled the dissection of these interactions at single-cell resolution, including microscopy, single-cell transcriptomics, proteomics, and emerging dual RNA-seq and spatial approaches. Drawing on examples from well-characterized bacterial pathogens like Listeria monocytogenes, Salmonella enterica, and Mycobacterium tuberculosis, we discuss how stochastic gene expression, intrinsic and extrinsic factors, as well as tissue context shape the variable activation of the immune responses and ultimately determine the outcomes of host-pathogen interactions. We argue that the outcome of single-cell interactions is shaped by a combination of host states, bacterial-intrinsic features, and the local microenvironment. We further discuss how computational and mathematical modeling can integrate these heterogeneous single-cell events across spatial scales, linking intracellular variability with tissue-level pathogenesis and progression of infection. Gaining insight into and controlling these layers of variability holds promise for the development of more precise, context-dependent antimicrobial strategies.

Keywords:
host-pathogen interactions, single-cell biology, cellular heterogeneity, infection biology, Listeria monocytogenes, Salmonella enterica, Mycobacterium tuberculosis

Abstract:
Nickel–titanium (NiTi) shape memory alloys (SMAs) with a nominal composition of 50.8 at% Ni and 49.2 at% Ti were fabricated using the as-fabricated laser powder bed fusion (LPBF) technique. This study focuses on the impact of post-processing heat treatments—specifically solution annealing and aging at 500 °C for 1 and 20 h—on phase transformation behavior and functional performance. Phase analysis (XRD) was conducted at room temperature (~ 25 °C), while uniaxial tensile testing was performed at both room (~ 25 °C) and sub-zero (–20 °C) temperatures. Differential scanning calorimetry (DSC) was carried out over a wide temperature range to evaluate the thermal behavior of the material. The results indicate that heat treatment conditions significantly affect transformation temperatures, phase constitution, and mechanical response. Depending on the treatment and test temperature, the microstructure varied from fully austenitic to fully martensitic or mixed-phase states. These variations manifested as distinct features in the stress–strain behavior, particularly in terms of martensitic transformation and superelasticity. The study demonstrates the feasibility of fine-tuning functional properties in LPBF-produced NiTi SMAs through optimized thermal processing strategies.

Abstract:
The design and optimisation of electrode and electrolyte materials to tune the properties of capacitors is a complex task with often unexpected outcomes. In this work, we assessed the electrochemical performance of a new carbon material, Graphene MesoSponge® (GMS), in combination with a flexible electrolyte, ionogel built from polyvinylalcohol polymer matrix and ionic liquid (IL) with ethylmethylimidazolium cations and bisulfate anions. From the electrochemical characterisations employing cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge, we established the superior performance of GMS compared to the activated carbon reference material. To gain insights into the unique chemistry of GMS structure and composition that lead to favourable electrochemical properties, we conducted density functional theory (DFT) simulations to examine the interactions of IL with the GMS material using nanoscale, periodic models of the pristine and two different defect site-containing graphene sheets. The dominant interactions in these systems are a network of H-bonds and dispersive interactions, similar in both systems, but favouring curved graphene due to its structural complementarity with IL ions. Changes to the electron density distributions relative to those of the separate components and the superimposed effect of cations/anions and polymer matrix interactions were used as the atomic-scale measure of surface wettability.

Abstract:
The rise in global carbon dioxide levels necessitates efficient, low-pollution energy technologies. Solid Oxide Fuel Cells (SOFCs) are promising energy converters, and their electrical performance is strongly influenced by the electrode microstructure. This study presents a comprehensive multiscale, experimentally grounded optimization pipeline for SOFC electrodes to maximize the electrical power density, integrating microscale and macroscale approaches. The methodology combines tomography-based microstructure characterization, computational homogenization, multiphysics simulations, model order reduction, and machine-learning-based surrogate modeling. Anode samples with fine, medium, and coarse grain sizes are analyzed using high-dimensional morphological descriptors to characterize microstructure morphology. Partial least squares discriminant analysis reduces the descriptor space to enable efficient surrogate modeling and generation of artificial microstructures by interpolation in the reduced space. Effective conductivities and permeability are computed by first-order homogenization and incorporated into a macroscopic fuel cell model to predict the power density. The proposed framework links microstructural information to macroscopic electrical performance within a nested optimization loop, enabling systematic exploration of physically realistic microstructural variants. Using a Ni-YSZ anode as a case study, the approach identifies the most suitable microstructure characteristics within an experimentally limited design space and provides a flexible optimization framework that can be adapted to different databases, models, and objective functions.

Keywords:
Optimization pipeline, Solid oxide fuel cells, Electrode microstructure, Multiscale modeling, Multiphysics modeling, Surrogate modeling

Abstract:
A comprehensive finite element-meshfree multiscale numerical framework is developed to investigate the size-dependent nonlinear asymmetric instability behavior of carbon nanofiber (CNF)-silicon carbide (SiC) nano-particle hybrid reinforced micro-arches subjected to radial concentrated loads applied at different positions. At the nanoscale, a finite-element-based homogenization strategy employing 3D periodic representative volume elements (RVEs) is developed to compute the effective elastic properties of nanocomposites reinforced with SiC nanoparticles and cylindrical CNFs, accounting for interphase characteristics. These homogenized material constants are subsequently incorporated into a nonlocal strain gradient theory (NSGT)-based radial point interpolation meshfree formulation, enhanced with an adaptive background decomposition integration approach to capture load location-sensitive nonlinear stability responses accurately. Numerical results demonstrate a pronounced multiscale coupling effect: increasing the CNF volume fraction from 1% to 4% results in approxi-
mately a 52% enhancement in all critical limit point loads, while increasing the SiC nanoparticle content from 1% to 5% increases them by nearly 29%. The relative interphase thickness provides a moderate gain of approximately 4.8%, and increasing the CNF aspect ratio strengthens the instability resistance by about 12.8%.
Conversely, increasing the SiC nanoparticle diameter results in a nearly 10.9% reduction in load-carrying capacity, indicating the superior reinforcing efficiency of smaller nanoparticles at a fixed volume fraction. Overall, the proposed framework successfully captures the highly nonlinear, curvature-sensitive, and size-dependent
instability characteristics of hybrid CNF-SiC micro-arches, offering a powerful predictive tool for the optimal design of advanced micro-scale structural components

Keywords:
Nonlinear stability, Meshfree approach, Size dependency, Finite element method, Hybrid composites

Abstract:
Low early-age strength is a significant barrier to the widespread use of multi-component cements with a low clinker factor in the construction materials industry. The low reactivity of supplementary cementitious materials used to replace Portland cement in mortar and concrete formulations is a primary factor contributing to inadequate early-age performance. This study investigates the reactivity enhancement of stockpiled granulated blast furnace slag (BS) through power ultrasound treatment (PUS) during mortar preparation. Reactivity was assessed using the Strength Activity Index (SAI), modified Chapelle test, and R3 heat release calorimetry. A custom-designed sonoreactor equipped with closed-circuit cooling was used to examine the effects of pulsed-mode PUS exposure on the consistency of fresh mortar and the mechanical properties of hardened specimens. Experimental investigations were conducted on mortar mixtures with a water-to-binder ratio of 0.5, in which BS replaced 20% of the cement by mass. PUS led to a 58% increase in early-age compressive strength; optimal results were achieved at 10 min. The influence of sonication duration, BS incorporation, and addition of a high-range water reducer on both early- and late-age strength development is systematically evaluated. The observed effects are explained by substantially increased reactivity, as evidenced by elevated heat release, and substantially enhanced dissolution of calcium, magnesium, and alkali metals from slag due to sonication.

Keywords:
Power ultrasound treatment, Granulated blast furnace slag, Early strength development, Portland cement, Cement-based composites

Abstract:
Increasing mechanical performance through fabrication advancements is a cornerstone of materials science. In this work, a nanometric protective Ni layer is applied to SiC reinforcement particles to enhance the wear resistance of co-electrodeposited metal matrix composites. The influence of this modification on the matrix-reinforcement interface is studied through electron microscopy and a novel micro-beam bending methodology. Direct micro-mechanical testing reveals a bonding paradox: the protective layer does not increase nominal interfacial strength, but increases wear resistance. The modification transforms the SiC reinforcement from insulators to surface-conductive particles, fundamentally altering the co-deposition mechanism. This leads to immediate particle encapsulation and a more homogeneous distribution of the reinforcement. Ultimately, protective layer suppresses interfacial porosity and ensures a continuous matrix-reinforcement contact resulting in higher wear resistance.

Keywords:
Metal-matrix composite, Interfacial bonding, Wear resistance, Co-electrodeposition

Abstract:
This work investigates experimentally and numerically the dynamics of rigid particles with two orthogonal symmetry planes settling under gravity in a highly viscous fluid at a Reynolds number much smaller than one. Joshi & Govindarajan (2025 Phys. Rev. Lett. 134(1), 014002), showed theoretically that for such shapes, the dynamics are qualitatively different for different signs of the product of two rotational–translational mobility coefficients, evaluated with respect to the particle centre of mass in a symmetric reference frame. However, upon examining a particle’s shape, it is not immediately evident if this product is negative, positive or zero. In this paper, we demonstrate how to estimate these coefficients and the sign of their product from experiments, using special initial orientations, and also numerically, based on the Stokes equations. Especially interesting are the ‘settlers’ – such particles that reorient and approach a stationary stable orientation, and we focus our study on this class of shapes. We show experimentally that cones, crescent moons, arrowheads and open flat rings are the settlers, and we evaluate from the experiments their rotational–translational mobility coefficients. Then, we reconstruct each experimental shape as a rigid conglomerate of many touching beads, and use the precise Hydromultipole code to calculate the mobility coefficients for the conglomerate. The numerical and experimental values are close enough to determine that the particles are the settlers, and to estimate the characteristic reorientation time scales. Our findings apply to non-Brownian micro-objects in water-based solutions – experimentally by the similarity principle and theoretically based on the Stokes equations. The reorientation of sedimenting rigid particles to a stationary stable configuration in a relatively short time might be used for environmental, biological, medical or industrial applications.

Keywords:
Stokesian dynamics, low-Reynolds-number flows, pattern formation

Abstract:
The limited lifetime of hot forging tools, caused by severe wear mechanisms such as abrasion, adhesion, thermal fatigue, and plastic deformation, remains a major challenge in forging operations. The study encompasses the entire process, from concept to industrial implementation. It begins with basic laboratory tests of the innovative material, followed by the application of protective coatings on an industrial scale to forging dies, which were then successfully used in production. The research presents the development and evaluation of novel hybrid surface treatments combining plasma nitriding with nanocomposite coatings based on tungsten boride alloyed with either tantalum (W-Ta-B) or titanium (W-Ti-B). The coatings were deposited using High Power Impulse Magnetron Sputtering (HiPIMS) from SPS-fabricated ternary targets. Laboratory characterization included structural, mechanical, tribological, and oxidation resistance analyses. The W-Ti-B films exhibited superhardness above 40 GPa and superior wear resistance, while the W-Ta-B coatings demonstrated enhanced oxidation resistance and adhesion. Both coatings revealed fine columnar microstructures and favorable H/E* and H³/E² ratios, indicating high resistance to plastic deformation and cracking. Industrial trials under hot forging conditions confirmed their effectiveness, with tool life extended by up to 80% compared with conventional nitrided tools. These findings demonstrate the strong potential of HiPIMS-deposited W-based boride coatings to significantly improve tool performance in demanding thermal and mechanical environments.

Keywords:
HiPIMS, Boride coatings, Hot forging tools, Nanocomposites, Durability

Abstract:
Rheumatoid arthritis (RA) remains a condition in which complementary, non-invasive assessment tools are actively explored. While previous thermography studies have focused mainly on temperature dynamics or
texture features, the diagnostic value of information-theoretic complexity measures is still not well understood. This study evaluates three such measures, Lempel–Ziv complexity (LZC), permutation complexity (PC), and
belief permutation entropy (BPE), for distinguishing RA patients from healthy individuals, with emphasis on the impact of different symbolic encoding strategies under no-cooling and cooling conditions. A dataset of 477 hand thermograms (291 healthy controls, 186 RA patients) was analyzed using four encoding schemes: binary, slope-direction, zero-crossing, and multilevel thresholding. All statistical conclusions were assessed at the
subject level using median aggregation per participant, with multiplicity-adjusted testing on protocol-matched cohorts to avoid within-subject dependence and availability bias. The primary endpoint was subject-level
discrimination quantified by effect size and ROC–AUC. Results indicate that the diagnostic utility of complexity measures in hand thermography strongly depends on both encoding choices and the acquisition protocol. Under
no-cooling conditions, several LZC variants and PC showed statistically significant but small group differences after BH-FDR correction (|

Keywords:
Rheumatoid arthritis, Infrared thermography, Information theory, Lempel–Ziv complexity, Permutation entropy, Belief permutation entropy, Symbolic encoding

Abstract:
This study deals with the problem of optimizing the geometry and motion of a two-segment articulated ichthyoid propulsor for autonomous underwater vehicles. The considered propulsor mimics the undulating body and caudal fin motion of a swimming fish; thus, the thrust and sideforce that are generated exhibit undesirable oscillations. The formulas for these hydrodynamic forces, which were derived in the author's previous work, are presented. For selected values of the mean thrust and the swimming speed, two problems of minimizing the thrust (1) and the sideforce (2) variance are solved by systematically searching the set of feasible solutions. Two considered objective functions lead to quite different results regarding the optimal geometry and motion of the propulsor. The propulsor minimizing the thrust variance should have the first segment shorter than the second one, and the propulsive fin should spread over almost the entire length of the second segment. When the objective is minimizing the sideforce variance, the first segment should be described by a length greater and the amplitude smaller than that of the second segment, and the propulsive fin should be small. For both objective functions, the optimal motion of the propulsor strongly depends on the swimming speed and generated thrust. Generating greater thrust at higher swimming speeds requires reducing the vibration period.

Keywords:
ichthyoid propulsor, fish swimming, autonomuos underwater vehicle, elongated body theory, optimization

Abstract:
In this study, tubular specimens of Inconel 625 and Inconel 718 were additively manufactured using the Laser Engineered Net Shaping (LENS) technique. Their initial yield surfaces were experimentally determined under biaxial stress loading at 0.005% and 0.01% plastic offset strain. Uniaxial tensile tests showed yield strengths of 509 MPa and 461 MPa, with Young’s moduli of 180 GPa and 171 GPa for Inconel 625 and Inconel 718, respectively. Yield surfaces, fitted using the Szczepiński anisotropic criterion, revealed elliptical shapes with axis ratios below 1.73, confirming moderate anisotropy. Inconel 625 exhibited nearly symmetric yield strengths in tension and compression, with a higher tensile-direction elongation of the surface, whereas Inconel 718 showed stronger directional dependence, reflecting a higher degree of mechanical anisotropy.

Keywords:
Inconel, Yield surface, Additive manufacturing, Laser Engineered Net Shaping

Abstract:
Functionally graded nickel-based coatings represent an advanced surface engineering approach designed to enhance the performance of components operating in high-temperature and harsh environments. Unlike conventional coatings with uniform composition, functionally graded coatings exhibit gradual variations in composition and microstructure across their thickness, enabling improved adhesion, reduced residual stresses, and enhanced multifunctional performance. This review provides a comprehensive overview of recent developments in nickel-based functionally graded coatings, focusing on substrate materials, coating compositions, and manufacturing technologies. Particular attention is given to coatings designed for high-temperature applications and harsh service conditions, including carbide-reinforced composite coatings and MCrAlY-type systems used for oxidation and corrosion protection. Various fabrication methods, including laser cladding, additive manufacturing, electrodeposition, and thermal spraying, are critically discussed in terms of their advantages and limitations. The current state of the art is analyzed with emphasis on coating performance in high-temperature and aggressive environments. Finally, key challenges and future research directions are identified, highlighting the need for improved long-term performance evaluation, advanced manufacturing approaches, and the development of multifunctional gradient coating architectures.

Keywords:
functionally graded coatings, nickel-based coatings, laser cladding, thermal barrier coatings, high-temperature surface engineering

Abstract:
Iron oxide (Fe2O3) is attractive for energy storage due to its low cost, abundance, and eco-friendliness, but suffers from poor cyclic stability and capacitance fading. Here, we systematically investigate how calcination temperature influences the structure, morphology, and electrochemical properties of surfactant-assisted self-assembled iron oxide nanoflowers. Variation of calcination temperature from 300 °C to 600 °C strongly affects the phase, crystal structure, morphology, surface area, porosity, and electrochemical properties of the oxides. The low-temperature calcination of iron oxide at 300 °C leads to a distinctive mesoporous flower-like morphology, high surface area (145.76 m2 g−1), and mixed-phase (maghemite and hematite) composition with low crystallinity, resulting in the highest specific capacitance (182.3 F g−1 at 1 A g−1), low internal resistance with enhanced capacitive behavior. In contrast, samples calcined at higher temperatures than 300 °C exhibit reduced surface area, enhanced phase purity (pure hematite), and diminished electrochemical activity. A low-cost pouch-type asymmetric capacitor is fabricated using Fe2O3 nanoflowers calcined at 300 °C and activated carbon, delivering 24.33 μWh cm−2 energy density, 448.91 μW cm−2 power density, and 78.8% capacitance retention with 97% coulombic efficiency after 10,000 cycles. These results underscore the pivotal role of calcination temperature in optimizing Fe2O3 nanostructures for efficient energy storage.

Keywords:
Iron oxide nanoflowers, Calcination temperaturę, Phase-morphology correlation, Pseudocapacitance, Asymmetric electrochemical capacitor

Abstract:
In this paper, we present an original ultrasonic technique to investigate and discriminate between different kinds of pork meat, i.e., hand-deboned (HD) meat and mechanically separated (MSM) meat. To this end, we measured the speed c of high-frequency f = 5 MHz ultrasonic waves propagating in the examined pork meat samples. The measured speed of longitudinal ultrasonic waves ranged from 1578 to 1610 m/s. Significant statistical differences were found between the speed of ultrasonic waves in the HD pork loin and pork neck, and those in various types of MSM.
The newly proposed measurement (analytical) method, based on the determination of ultrasonic velocity, can be effectively applied to distinguish between manually separated (HD) and mechanically separated (MSM) pork meat. Importantly, the obtained experimental results were supported by a statistical
analysis, showing highly significant correlations between the speed of ultrasonic waves and the content of water, protein, fat and sodium in the measured pork meat samples.

Keywords:
physicochemical parameters of meat, mechanically separated meat (MSM), hand-deboned (HD) meat, speed of sound, protein content, fat content, water content, sodium content

Abstract:
This study advances beyond qualitative strength reduction trends in additive manufacturing fracture studies by establishing quantitative, configuration-based fracture assessment for Binder Jetting Additive Manufactured (BJ-AM) 17–4PH stainless steel with engineered surface cracks. Multiple crack geometries such as edge, inclined, single-corner, and double-corner configurations were precisely implanted in square (7 × 7 mm) and rectangular (3.5 × 14 mm) specimens with identical cross-sectional areas. Experimental investigations demonstrate that fracture resistance is governed by crack configuration and geometry-induced constraint, not crack area alone. Double-corner cracks retained 79–86% strength despite 25% crack area, while single-edge cracks exhibited 46–54% retention with only 20% crack area. Thickness-dependent constraint effects unique to BJ-AM geometries were quantified through comparative testing, revealing rectangular specimens (3.5 mm thickness) exhibit reduced constraint and lower fracture resistance than square specimens (7 mm thickness). J-integral governed elastic-plastic fracture assessment, validated through Extended Finite Element Method simulations predicting failure within ±10%, establishing predictive frameworks for defect-tolerant BJ-AM structural design.

Keywords:
Binder jetting additive manufacturing, Fracture toughness, J-integral, Extended finite element method, Surface cracks, 17–4PH stainless steel

Abstract:
This study presents the results of investigations on the influence of raw material type and synthesis method of cadmium yellow on the electrokinetic potential of pigment particles and the sedimentation stability of the resulting dispersions
in various chemical environments. Pigments were synthesized from cadmium salts (chloride, sulfate, nitrate, and carbonate) using sodium sulfide or elemental sulfur as sulfur sources. Two synthesis routes were applied: (1) precipitation of
the pigment from solution, followed by filtration, drying at 60 °C, and calcina-tion at 600 °C in acidic and alkaline media; and (2) direct reaction of cadmium carbonate with sulfur at 600 °C. The materials were characterized using Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The zeta potential of
the particles was measured at different pH values, and dispersion stability was evaluated by turbidimetric analysis (Turbiscan). The obtained pigments were mixtures of compounds, with cadmium sulfide (CdS) being the predominant component. The chemical composition depended on the synthesis route and the
calcination process. A correlation was found between the electrokinetic potential,sedimentation stability, and chemical composition of the pigments. Calcination significantly affected surface properties, while the presence of chloride, sulfite,
sulfate, and carbonate species modified the electrokinetic potential. Acidic envi-ronments were found to enhance the sedimentation stability of cadmium-based pigments. The findings highlight the importance of synthesis conditions for the
surface chemistry, electrokinetic behavior, and sedimentation stability of cad-mium-based pigments in aqueous systems.

Abstract:
This study introduces a proof-of-concept methodology for evaluating pressure-dependent non-linear acous- tic properties of liver tissue. The proposed non-linearity index (NLI) is derived from echo amplitudes obtained at two substantially different acoustic pressures. Unlike previous harmonic-based approaches, the method relies solely on the fundamental frequency band, allowing clinical implementation without additional system mod-ifications. The image acquired for the lower pressure is then amplified to correct for the pressure difference between the beams. Next, the NLI is estimated as a ratio of local amplitudes of the amplified low-pressure
image (ALPI) to the high-pressure image (HPI). In the case of nonlinear media some energy of the wave is transferred from the pulse fundamental frequency to higher harmonics, which affects mainly the HPI. With the harmonics being filtered out from the signal, the HPI amplitude becomes lower than the ALPI amplitude.As a result, the NLI becomes higher than 1 and increases with the non-linearity of the imaged tissue. The
hydrophone measurements were compared to the simulation (k-Wave) of the ultrasonic field in water and veg-
etable oil. Next, we performed NLI imaging of healthy and fatty livers using SonixTouch (Ultrasonix) systems and two acoustic pressures of 390 kPa and 1590 kPa. Preliminary studies – imaging healthy and fatty livers using SonixTouch (Ultrasonix) systems were performed on the 4 livers of the authors of the article showed that for ‘healthy’ livers the NLI was below 1.1, while in one of the authors with previously diagnosed steatosis falling between score 1 and 2, the NLI locally exceeded 1.3.These results show that the obtained NLI values increase with the degree of steatosis, which agrees with theoretical expectations based on tissue B/A coefficients. The work emphasizes methodological feasibility and physical consistency rather than clinical validation, given the limited number of volunteers and ethical restrictions on patient recruitment.

Keywords:
ultrasound imaging, abdominal ultrasound

Abstract:
Ensuring effective protection for payloads during aerial operations—whether involving drones, helicopters, or airdropped objects—remains a critical challenge due to their widespread commercial and military use. This paper proposes an adaptable airbag-based protection system equipped with innovative semi-passive valve for controlled gas outflow. The introduced valve incorporates a custom-shaped shutter vent and, unlike typical kinematics-driven solutions such as metering pins, utilizes pressure-driven motion of a mobile valve’s piston during the landing process. The predesigned dynamics of the valve’s piston enables the required change in the shutter vent area, allowing precise outflow control and consequently ensuring desired force and deceleration profiles. Optimal valve design is achieved through a hybrid analytical–numerical method, iteratively alternating between an analytical system model and CFD simulations of gas outflow. It is demonstrated that the proposed adaptable system dissipates the entire impact energy and maintains protected object’s deceleration at almost constant level, achieving efficiency comparable to semi-active systems. As a result, it effectively minimizes overloads during emergency landings and increases safety of passengers and payloads.

Abstract:
In this review, a comprehensive analysis of aluminide coatings for nickel-based superalloys was performed with the particular emphasis on their processing, microstructural evolution, and performance under high-temperature conditions. Nickel-based superalloys are widely used in power engineering and aerospace industries; however, their susceptibility to oxidation and hot corrosion necessitates advanced surface protection strategies. Aluminide coatings offer effective protection through the formation of stable and adherent alumina scales. The review systematically evaluates major deposition techniques, including chemical vapour deposition (CVD), pack cementation, slurry aluminizing, and advanced hybrid methods, highlighting their influence on coating structure and properties. Special attention is given to the relationship between processing parameters, microstructure, and functional performance, including oxidation resistance, corrosion behaviour, and mechanical properties such as hardness and fatigue life.

Keywords:
aluminide coatings, nickel-based superalloys, chemical vapour deposition, pack cementation, slurry aluminizing, high-temperature oxidation

Abstract:
The oxygen evolution reaction (OER) using noble metal-based catalysts faced significant commercialization challenges due to the scarcity and substantial expense of these noble metals. Thus, the development of an efficient OER electrocatalyst for proton exchange membrane (PEM) water electrolyzers is still a challenging task. Herein, we present a facile approach to preparing cobalt phthalocyanine anchored on N-doped Co3O4 carbon network (Co3O4-NC) derived from metal organic framework (MOF). This strategy facilitates fast electron transfer and modulates the electronic structure. This improved electron transport induced by CoPc plays a significant role in enhancing OER, requiring only an overpotential of 1.2 V to deliver a current density of 1000 mA cm−2 with excellent stability. The Co3O4-NC2 Pc catalyst shows excellent durability during PEM water electrolysis and delivers industrially required current density of 1000 mA cm−2 at a potential of 1.66 V, outperforming commercial RuO2. The results of this research are twofold. Firstly, they promote green and low-carbon development. Secondly, they inject new vitality into the development of hydrogen energy technologies.

Keywords:
noble-metal free catalyst, oxygen evolution, phthalocyanine doped metal oxide, proton exchange membrane, water electrolysis

Abstract:
Present investigation systematically quantifies the role of interior defect morphology on tensile fracture behavior in Binder Jetting Additive Manufactured (BJAM) 17-4 PH stainless steel. Unlike prior investigations relying on stochastic natural defects, BJAM is uniquely employed to fabricate tensile specimens with five precisely controlled interior defect geometries such as spherical, disc-shaped, ellipsoidal, inclined ellipsoidal, and two-spherical at the mid-gauge location of round and square cross-sectional configurations. These artificial defects, occupying 16–35% of the gross cross-sectional area, serve as morphologically defined analogues of shrinkage porosities typical of conventional steel castings. A novel shape-independent empirical net section yielding method is developed that directly correlates projected defect area to fracture stress across all five defect geometries and both cross-sectional configurations. Results demonstrate that tensile strength reduction is governed by projected defect area independent of defect shape, with predictions falling within ±10% for the majority of configurations, providing a practically applicable fracture stress prediction tool for defect containing BJAM components. 3D finite element simulations coupled with a ductile damage model are implemented to accurately predict crack initiation sites and experimental load–displacement responses, achieving excellent agreement with experimental findings and providing independent computational validation of the empirical framework.

Keywords:
Binder jetting additive manufacturing, Ductile damage model, Interior defects, Shrinkage porosity, 17-4PH steel

Abstract:
In the present exploration, by unifying the simplified unit cell (SUC) micromechanical approach with the isogeometric numerical technique, a new solution model is developed to examine the small-scale dependent nonlinear stability feature of fuzzy fiber reinforced composite (FFRC) microplates under in-plane axial compression. A notable structural feature of this hybrid composite is the presence of uniformly aligned radially grown carbon nanotubes (CNTs) on the surfaces of the glass fibers, all of equal length, together with the interphase area between the nanotubes and the polymer material. Additionally, the interphase region between CNTs and the matrix is modeled as a distinct phase. To capture the influence of material microstructure, the effective elastic constants are first predicted using the SUC micromechanics model, while size-dependent effects are incorporated through the modified strain gradient theory. These material characteristics are then combined with an isogeometric plate formulation to enable accurate and efficient numerical analysis of FFRC microplates with different geometries and boundary conditions. The results show that the presence of CNTs as well as the interphase region significantly enhances both the buckling resistance and postbuckling stability through improving the stiffness and load transfer capability, particularly when the interphase becomes thicker or stiffer. The examination also highlights the influence of glass fiber volume fraction as well as the role of strain gradient tensors in enhancing the load-bearing capability. Overall, the proposed framework provides a consistent link between micromechanical design features and structural-scale stability performance of FFRC microstructures.

Keywords:
Micromechanical model, Fuzzy fiber-reinforced composite, Size dependency, Interphase region

Abstract:
Niobium nitride (δ-NbN) coatings were deposited on AISI 316L austenitic steel using reactive DC magnetron sputtering. This study investigates the effects of air oxidation on the surface morphology, topography, roughness, nanohardness, adhesion, and wear resistance of NbN coatings. Their microstructure and thickness were analyzed by scanning electron microscopy (SEM), while surface morphology and roughness were assessed using atomic force microscopy (AFM), and surface topography was assessed by an optical profilometer. Nanohardness was measured using a Berkovich indenter. Adhesion was evaluated via progressive-load scratch testing and Rockwell indentation (VDI 3198 standard). Wear resistance was assessed using the “ball-on-disk” method. Both as-deposited and oxidized NbN coatings improved the mechanical performance of the substrate surface. Air oxidation led to the formation of an orthorhombic Nb2O5 surface layer, which increased surface roughness and reduced hardness. However, the brittle oxide also contributed to a lower coefficient of friction. Despite reduced adhesion and increased surface development, the oxidized coating exhibited a significantly lower wear rate than the uncoated steel, though several times higher than that of the non-oxidized NbN. Considering its good wear and corrosion performance, along with the bioactivity confirmed in earlier research, the oxidized NbN coating can be considered a promising candidate for biomedical applications.

Keywords:
Nb2O5, NbN, magnetron sputtering, oxidation, adhesion, wear, surface engineering

Abstract:
Transition metal borides are attracting increasing interest due to their unique properties. They are not only characterised by very high hardness, but also considerable chemical and thermal stability. Silver, on the other hand, is a good material for increasing electrical and thermal conductivity, wear resistance and has antibacterial properties due to its biological characteristics. Combining these two materials can provide superhard bilayers with increased functional properties. In this study, it was decided to synthesise Ag/WB2.5, Ag/W0.76Ti0.24B2.5 coatings and compare their properties to the individual components. The silver coating was produced by pulsed laser deposition (PLD), while the WB2.5 and W0.76Ti0.24B2.5 coatings were formed by high-power pulsed magnetron sputtering (HiPIMS). To determine the mechanical properties, nanoindentation tests, adhesion of the coatings by scratch -test and wear resistance by abrasion in reciprocating motion were tested. In all cases, the silver film contributed to an increase in the wear resistance of the materials without major changes in the hardness results of the materials. In addition, the Ag/W0.76Ti0.24B2.5 film showed very good adhesion to the substrate. Human hand wiping simulator was also carried out using - Tribotouch. After 36 000 cycles Ag/W0.76Ti0.24B2.5 coating was slightly deformed, which was not visible macroscopically. This result is more than three times greater than for the pure silver film. It was also decided to carry out corrosion tests in an environment of 0.9% NaCl. The Ag/W0.76Ti0.24B2.5 bilayer has very good corrosion resistance, similar to pure silver.

Keywords:
Granular materials, Thermal, Electric, Discrete element method, Explicit time integration

Abstract:
A heavy-atom-free and non-toxic spirocyclic C-BODIPY singlet oxygen photosensitizer was successfully incorporated into electrospun polymeric nanofibers. Optimization of the material composition revealed that polycaprolactone (PCL), an FDA- and EMA-approved, biodegradable, easily accessible, and cost-efficient polymer, doped with BODIPY at a concentration of only 0.15 wt %, is an efficient photocatalyst for the degradation of the pharmaceutical agents ranitidine, propranolol, and cimetidine, selected as model water pollutants. The obtained nanofibers showed smooth and uniform morphology along with very high durability and resistance toward oxidation, remaining active even after 20 reaction cycles. EDX, ToF-SIMS and XPS analyses confirmed the homogenous distribution of BODIPY within the polymeric matrix. Furthermore, the materials showed significant photoinactivation of Staphylococcus aureus under white light irradiation compared to the control experiment performed without irradiation. These findings highlight the potential of the electrospun PCL nanofibers as optimal matrix for the immobilization with singlet oxygen photosensitizers and subsequent application in the decontamination of water from pollutants and pathogens.

Keywords:
antimicrobial photodynamic therapy, heavy-atom free photosensitizers, immobilization, polycaprolactone, singlet oxygen, water purification, BODIPY, electrospun nanofibers

Abstract:
Enhancing the stability and suppressing charge recombination in perovskite quantum dots in aqueous environment is a prerequisite for practical application in artificial photosynthesis. In this study, we confine CH3NH3PbBr3 (MAPs) perovskite nanocubes in the porous of zeolitic imidazole framework via a sequential trapping and growth activation strategy, resulting in composite photocatalyst for CO2 reduction to methane. The MAPs were in proximity with Co catalytic site in the ZIF, which facilitate rapid transfer of photogenerated electron from the MAPs to Co site with corresponding enhancement in photocatalytic CO2 reduction. The hybrid MAPs@ZIF show efficient photocatalytic CO2 reduction to Co with selectivity of 8.7% and CH4 with selectivity of 91.3%, which is far high than the photocatalytic activity for ZIF in the absence of PQDs. The DFT investigation revealed that the Co is the photocatalytic active site and the lowering of bandgap around the fermi energy level in the hybrid MAPs@ZIF compared to the individual components.

Abstract:
Laser-induced graphene (LIG) offers a promising platform for lithium-ion battery electrodes due to its high conductivity and porous three-dimensional architecture; however, its limited electrochemical activity restricts practical application. This study presents poly(3,4-ethylenedioxythiophene) -modified LIG cathodes prepared via two distinct polymerization strategies. In the first approach, 3,4-ethylenedioxythiophene monomers are polymerized in solution with an oxidant before deposition onto LIG. In the second approach, the monomer is first deposited onto the LIG surface, followed by separate oxidant introduction to confine polymerization directly at the electrode interface. Structural characterization confirms successful polymer incorporation while preserving the porous LIG framework. The surface-confined approach yields more uniform polymer distribution and stronger polymer-substrate interaction, as evidenced by enhanced π–π coupling observed in Raman spectra. Electrochemical evaluation reveals that polymer loading significantly affects performance, with an optimal monomer volume providing balanced coverage without pore blockage. Electrodes prepared via surface-confined polymerization deliver a specific capacity of approximately 170 mAh g−1 at 0.003 A g−1, representing a tenfold improvement over pristine LIG, and retain 85% capacity after 100 cycles. Electrochemical impedance spectroscopy confirms reduced charge-transfer resistance and improved ion diffusion for this approach. These findings establish poly(3,4-ethylenedioxythiophene) -modified LIG as a promising metal-free cathode material for flexible lithium-ion batteries.

Keywords:
Energy storage, Laser-induced graphene, Polymer coating, Plasma treatment, Lithium-ion battery

Abstract:
Ferritic–martensitic P91 steel is widely used in high-temperature power plant components due to its excellent creep resistance and mechanical stability. However, long-term service exposure and improper heat treatment can lead to progressive microstructural degradation, resulting in a reduction of mechanical properties and component lifetime. Reliable, non-destructive methods capable of detecting such microstructural changes are therefore essential for condition monitoring and life assessment. In this study, the influence of controlled heat treatment at temperatures ranging from 200 °C to 600 °C on the eddy current (EC) response of P91 steel was investigated. Eddy current measurements were performed over a range of probe operating frequencies, and changes in resistance and reactance components were quantitatively analyzed. The EC results were correlated with detailed microstructural observations, revealing a strong relationship between electromagnetic response and recovery and tempering phenomena, including dislocation density reduction, martensite lath degradation, and carbide coarsening. The findings demonstrate that eddy current testing is highly sensitive to thermally induced microstructural evolution in P91 steel and shows significant potential as a non-destructive tool for assessing thermal exposure and material degradation in power plant components.

Keywords:
Non-destructive testing, Power engineering steels, Eddy current, Coil impedance,

Abstract:
W 2024 roku zaczęło obowiązywać rozporządzenie Unii Europejskiej w sprawie stopniowego wycofywania gazu izolacyjnego – heksafluorku siarki – stosowanego w układach wysokiego napięcia. Związek ten uważa się za bardzo silny gaz cieplarniany. Z tego powodu zaistniała pilna potrzeba znalezienia alternatywnego gazu, który mógłby zastąpić dotychczasowe rozwiązanie. W artykule przedstawiono wyniki wstępnych badań gazów, które mogłyby być wykorzystane w układach wysokiego napięcia. W specjalnie zaprojektowanym układzie ciśnieniowym wyposażonym w układ elektrodowy przeprowadzono pomiary wyładowań niezupełnych metodą akustyczną oraz pomiary wytrzymałości elektrycznej. Badania przeprowadzono przy kilku różnych poziomach nadciśnienia. Porównano wyniki wytrzymałości powietrza, dwutlenku węgla, azotu i argonu.

Keywords:
wytrzymałość elektryczna, wyładowania niezupełne, gazy elektroizolacyjne, emisja akustyczna

Abstract:
Thermal residual stresses generated during the cooling of metal–ceramic
composites produced by powder metallurgy remain a critical challenge for ensuring their reliable performance. The objective of this paper is to present and assess a methodology for constructing a finite element model for determining thermal residual stresses in metal-ceramic composites using the microstructure of the composite obtained from X-ray microcomputed tomography (micro-XCT) images for the mesh creation. The effectiveness of the micro-XCT-based finite element model is validated through a case study of residual stress behavior observed in an alumina-chromium composite that was consolidated by hot pressing. The influence of the choice of material models for the matrix and reinforcement and of the type of finite elements on the accuracy of the numerical simulations is analyzed. A comparison between the computed residual stresses and neutron diffraction measurements demonstrates a correlation validating the modeling approach. Of all the factors considered in the micro-XCT-based finite element simulations such as mesh quality, constitutive models for phase materials and the temperature dependence of the coefficients of thermal expansion mesh quality had the greatest impact on the accuracy of the numerical results in comparison to the residual stress measurement data
obtained from neutron diffraction.

Keywords:
Finite element analysis, metal-ceramic composites, microcomputed X-ray tomography, size effect, thermal residual stress

Abstract:
Monkeypox is a reemerging zoonotic disease that has been spreading worldwide. Different approaches are being conducted to find effective treatments for this disease. To accelerate therapeutic discovery, we propose telomere-binding protein (TBP) as a potential drug target because of its important role during virus maturation. Using computational biology and biophysics techniques, the MPXV TBP was modeled, and a library of FDA-approved drugs and phytocompounds was screened using a rigorous ensemble docking protocol; conformational sampling was enhanced by enumerating, for each ligand, ionization states, tautomerism, and ring conformations. Our results present a new approach to drug selection against MPXV, with six potential inhibitors: CHEMBL3894860, CHEMBL461101, CHEMBL2103870, PNSC125, PNSC305, and PNSC123, which can be taken as lead compounds for experimental testing, for example, in plaque reduction assays and qPCR in MPXV-infected cells to determine EC50, CC50, and selectivity index (SI) values.

Keywords:
drug screening, ensemble docking, Monkeypox virus, telomere binding protein

Abstract:
Accurate prediction of many-body dispersion (MBD) interactions is essential for understanding the van der Waals forces that govern the behavior of many complex molecular systems. However, the high computational cost of MBD calculations limits their direct application in large-scale simulations. In this work, we introduce a machine learning surrogate model specifically designed to predict MBD forces in polymer melts, a system that demands accurate MBD description and offers structural advantages for machine learning approaches. Our model is based on a trimmed SchNet architecture that selectively retains the most relevant atomic connections and incorporates trainable radial basis functions for geometric encoding. We validate our surrogate model on datasets from polyethylene, polypropylene, and polyvinyl chloride melts, demonstrating high predictive accuracy and robust generalization across diverse polymer systems. In addition, the model captures key physical features, such as the characteristic decay behavior of MBD interactions, providing valuable insights for optimizing cutoff strategies. Characterized by high computational efficiency, our surrogate model enables practical incorporation of MBD effects into large-scale molecular simulations.

Abstract:
One of the most promising green solutions to the growing need for renewable, environmentally friendly and not expensive energy sources, that can replace fossil fuels, is oxygen production during water electrolysis. The authors present gold and gold-semiconductor electrodes based on periodic self-assembled polystyrene spheres template for efficient oxygen evolution reaction (OER) via water splitting. The two-dimensional ordered Au crystal (OAuC) exhibits onset overpotential 1.63 V vs. RHE (reversible hydrogen electrode) with small Tafel slope of 76 mV dec−1 with excellent stability profile. The distinct ordered feature of the OAuC confers promising potential as electrocatalyst for OER.

Keywords:
Alkaline media, gold periodic electrodes, oxygen evolution reaction, water electrolysis

Abstract:
Current graph neural network (GNN) model-stealing methods rely heavily on queries to the victim model, assuming no hard query limits. However, in reality, the number of allowed queries can be severely limited. In this paper, we demonstrate how an adversary can extract a GNN with very limited interactions with the model. Our approach first enables the adversary to obtain the model backbone without making direct queries to the victim model and then to strategically utilize a fixed query limit to extract the most informative data. The experiments on eight real-world datasets demonstrate the effectiveness of the attack, even under a very restricted query limit and under defense against model extraction in place. Our findings underscore the need for robust defenses against GNN model extraction threats.

Keywords:
recycled materials, end-of-life tiers, rubber, fibres, concreto

Abstract:
Ultrasound (US) is a widely used imaging modality due to its availability, relatively low cost, and high frame rate. However, the quality of US images is usually considered inferior compared to other modalities, which can make image interpretation and the development of computer-aided diagnostic systems more challenging. In this work, we propose a deep reinforcement learning approach for US image denoising. Our method employs a software agent that learns to select both the location and types of interpretable image processing filters to apply. We demonstrate that the agent effectively reduces speckle noise in homogeneous regions while preserving or enhancing the structural details at the boundaries between such regions. Compared to other deep learning methods, our approach is based on well-known and simple filtering operations, making the denoising process more transparent and easier to interpret.

Keywords:
reinforcement learning, ultrasound, despeckling, image enhancement

Abstract:
The electrochemical performance of cobalt-based supercapacitor electrodes is often limited by the relatively smooth surface of pristine nickel foam substrates. To overcome this limitation, a microstructurally engineered nickel foam scaffold was fabricated by introducing a porous nickel microparticle interlayer via screen printing. Cobalt nanostructures were hydrothermally grown on the modified substrate, forming a hierarchical electrode (Co@NF-M), which was systematically compared with electrodes prepared on commercial nickel foam (Co@NF). Structural and spectroscopic analyses supported the formation of predominantly crystalline spinel Co3O4, characterized by mixed Co2 + /Co3+ oxidation states. Morphological analysis further demonstrated a porous cobalt nanostructure anchored onto a roughened nickel scaffold, providing abundant active sites and facilitating electrolyte penetration and ion diffusion. Electrochemical impedance spectroscopy indicated a reduced charge-transfer resistance and improved electron transport compared to the conventional Co@NF electrode. As a result, the Co@NF-M electrode exhibited superior electrochemical performance, delivering specific capacitances of 1278, 1184, 1003, and 602 F g−1 at 0.5, 1, 5, and 10 A g−1, respectively. Furthermore, the symmetric Co@NF-M//Co@NF-M device retained 95% of its initial capacitance after 3000 cycles, demonstrating excellent cycling stability. The enhanced performance is attributed to the engineered nickel scaffold, which promotes more uniform cobalt growth and improves interfacial contact while facilitating electron and ion transport.

Keywords:
Cobalt oxide, Symmetric supercapacitor, Cycling stability, Tailored Nickel foam, Pseudocapacitor behavior

Keywords:
beton osłonowy, projektowanie, trwałość

Abstract:
This study employs molecular dynamics simulations to examine the mechanical properties, fracture toughness, and crack propagation behavior of polycrystalline B6N6, BN, BC3, and C3N4 nanosheets and nanotubes. The effects of the number of grains, temperature, strain rate, edge pre-cracks, and circular-notch defects on Young's modulus, tensile strength, failure strain, and critical fracture toughness is systematically analyzed. Results show that increasing the number of grains reduces both tensile strength and Young's modulus, with BN nanosheets demonstrating the highest overall mechanical performance. Polycrystalline B6N6 exhibits the greatest fracture toughness, followed by BN, BC3, and C3N4, reflecting the role of atomic structure and bonding in energy absorption before failure. Thermal analysis indicates that BN maintains superior mechanical stability at elevated temperatures due to reduced atomic vibrations and stronger B–N bonds. Analyses of pre-cracks and notches reveal that BN is most sensitive to crack propagation, whereas BC3 and C3N4 show crack-insensitive behavior, with failure often initiating at grain boundaries rather than crack tips. Strain rate effects suggest that higher rates enhance fracture toughness by limiting atomic rearrangements and crack growth. For nanotubes, increasing diameter enhances Young's modulus but reduces tensile strength, failure strain, and fracture toughness, with C3N4 nanotubes being most sensitive to temperature. These findings provide detailed insights into the mechanical behavior of polycrystalline nanosheets and nanotubes, guiding the design of nanomaterials with optimized strength, toughness, and thermal stability for advanced applications.

Keywords:
Polycrystalline nanosheetsNanotubesMechanical propertiesFracture toughnessCrack propagation

Keywords:
orthopaedic implants, implant’s destruction, intramedullary nail, bone plate, surface analysis

Keywords:
additive manufacturing, direct energy deposition, thermal history, numerical simulations

Keywords:
high-temperature oxidation, nickel-based superalloys, microstructure, oxide scale formation

Keywords:
complex concentrated alloys, mechanical alloying, powder metallurgy, microstructure, mechanical properties

Keywords:
plastic deformation, Inconel 718, LENS, EBSD

Keywords:
additive manufacturing, LENS, yield surface, deformation, superalloy, inconel, multiaxial, EBSD, pre-deformation, anisotropy

Abstract:
This study investigatesd the hot stamping friction behaviour of TC4 aolly sheet using a self-developed high-temperature sheet tensile tribometer. The effects of contact pressure, lubrication (dry vs. Y₂O₃ powder), sheet temperature, and sliding speed on the coefficient of friction (COF) and wear mechanisms were evaluated. Increasing contact pressure induced a transition from ploughing to adhesion-dominated wear, raising the COF. Y₂O₃ powder lubricant formed a protective film that reduced the COF, though its effectiveness degrades under high pressure or low temperature. Elevating the sheet temperature decreased surface hardness and promoted adhesive wear, resulting in a more than 54% reduction in COF. Furthermore, an interactive multi-physics-based COF prediction model was developed, which captures friction evolutions under different conditions with high accuracy (prediction errors <6.8%). These findings provide insights for friction control in the hot stamping of titanium alloys.

Keywords:
TC4, Hot stamping process, Friction, Wear, Modelling