Najnowsze publikacje

Streszczenie:
This study investigates the multi-scale composite engineering of diatomite powder (DP)-modified micro-concrete subjected to power ultrasound (PUS) treatment. The main findings demonstrate that the combined DP + PUS treatment significantly improves macroscopic performance, increasing 28-day compressive strength by 60% in diabase (DI, 43.6 MPa) and 55% in limestone (LS, 44.1 MPa) systems, despite a 20% cement replacement. Microstructurally, DP selectively eliminates large macropore defects (>1000 nm) predominantly localized at the aggregate-paste boundary, as independently confirmed by fluorescence microscopy and SEM, reducing their volume fraction from 5.22% to 0.26% (DI) and from 3.43% to 0.56% (LS). In limestone systems, PUS further decreases the interfacial transition zone (ITZ) width by ∼62% (from ∼150 μm to 57.4 μm) and increases cement matrix hardness by 27.4%. Lu-Torquato spatial modelling confirms that this ITZ narrowing reduces the 3D weak-phase volume fraction from 3.0% to 1.1%, effectively disrupting the percolated interfacial network. Mori–Tanaka micromechanical homogenization further predicted a corresponding 7.5% increase in composite elastic modulus (32.2 → 34.6 GPa), confirming the mathematical coherence between microstructural refinement and macroscopic stiffness gains. These results provide direct experimental evidence that macroscopic strength is primarily governed by the selective elimination of large macropores and ITZ refinement rather than a mere reduction in total bulk porosity.

Słowa kluczowe:
Particulate composite, Interfacial transition zone, Micromechanical homogenization, Power ultrasound treatment, Diatomite powder, Nearest-surface distribution, ITZ percolation

Streszczenie:
Machine-learning representations of gait waveforms are increasingly used in movement analysis, but their added value over conventional biomechanical descriptors remains uncertain, particularly in pediatric cohorts. We evaluated whether implicit neural representations (INRs) provide useful encodings of pediatric gait waveforms for reconstruction and developmental modeling. The full cohort comprised 78 healthy children
and adolescents, of whom 73 had waveform files conforming to the predefined data structure required for the repeated cross-validation analyses. Selected waveforms were modeled using several INR architectures, and reconstruction quality was assessed using

Słowa kluczowe:
Pediatric gait, Biomechanics, Waveform analysis, Implicit neural representations, Movement development, Gait analysis

Streszczenie:
This paper describes a software toolbox for LiDAR (Light Detection and Ranging) and LiDAR-Inertial Odometry qualitative and quantitative evaluation. We provide software as https://github.com/MapsHD organization with all necessary information at https://github.com/MapsHD/HDMapping. Our software contributions are a) ground truth data processing tool, b) dockerized state-of-the-art LO and LIO algorithms, c) multi-session data registration to common coordinate system, d) Absolute Pose Error (APE) and Relative Pose Error (RPE) metrics, e) import/export tools for easier 3D data handling and visualizing, e.g., in Cloud Compare software. This software is compatible with ROS1 (Robot Operating System) and ROS2 data formats. We show an example benchmark of LeGO-LOAM, LIO-SAM, FAST-LIO, DLO, VoxelMap, Faster-LIO, KISS-ICP, CT-ICP, SLICT, DLIO, GLIM, iG-LIO, LIO-EKF, I2EKF-LO, GenZ-ICP, RESPLE, odometry_ros_wrapper, Point-LIO, and LOAM-Livox algorithms. For all experiments we provide movies. The contribution of the paper is software-oriented LO/LIO algorithm benchmark suite. The novelty lies in the integration of multiple benchmarking steps into a unified framework, thus overall effort needed for qualitative and quantitative evaluation is reduced.

Słowa kluczowe:
LiDAR odometry, LiDAR-inertial odometry, Benchmarking

Streszczenie:
This study develops and thoroughly evaluates a novel post-processing drift-correction method based on Shepard-type inverse-distance weighted (IDW) interpolation of displacement vectors. The algorithm maps local displacements of the entire handheld laser scanner (HLS) IR_RAW point cloud using sparse control points whose coordinates are determined with high-accuracy reference techniques (HLS in blue-light marker mode, terrestrial laser scanning (TLS), and electronic total station). The influence of control-point density (spacing 0.25–2.10 m), number of neighbors (K = 2–10), and weighting power (P = 1–3) was systematically analyzed on both a test brick wall and a real 14th-century city walls fragment in Koszalin, Poland. Cloud-to-cloud distance comparisons with independent TLS reference datasets demonstrated a dramatic improvement in geometric fidelity. In the test measurements, the share of points with errors below 3 mm rose from 35.5% (raw data) to 83–88% under optimal configurations (dense control grid, K = 4–8, P = 1–2). On the heritage wall, the best variants achieved over 92% of points within 3 mm. Local discontinuities were effectively suppressed, and the corrected clouds enabled reliable, millimeter-scale identification and quantification of material losses fully consistent with TLS results. The correction based on Shepard-type IDW interpolation significantly expands the applicability of affordable HLS technology for precise documentation and long-term monitoring of elongated cultural heritage structures at the scale investigated in this study, providing clear practical recommendations for control-point network design and algorithm parameter selection.

Słowa kluczowe:
Terrestrial laser scanning, Handheld scanner, City walls, Geometric drift correction, Medieval city walls

Słowa kluczowe:
Spiking neural networks, Learning rules, Spike trains, Temporal classification, Lempel–ziv complexity, Computational efficiency

Streszczenie:
Single crystals of pure zinc were examined using instrumented spherical indentation on the basal-oriented surface at three different loading rates. The residual impressions and the surrounding surface were investigated using atomic force microscopy and electron backscatter diffraction in order to reveal information about the topography and orientation changes. Noticeable pop-ins were reproducible in the majority of the tests. Contrary to reports in the literature, the pop-in initiation load and loading rates were found to have an inverse relationship, and this behaviour was attributed to twinning deformation and dislocation movement. In tests with all loading rates, evidence of twinning could be found both within and outside of the imprints. Residual impressions composed of slip and twin ‘subgrains’ and external twins manifested as sink-in patterns were observed in most of the tests, and the difference lay in the dissimilar twin formations at different loading rates. A hypothesis was developed to address the change in deformation behaviour within the subsequent loading process after a pop-in event.

Streszczenie:
A gadolinium hydroxide–MXene nanocomposite was synthesized through a microwave-assisted route as a supercapacitor electrode material. The prepared electrode material demonstrated a specific capacity of 128 mAh g−1, along with 98% capacitance retention after 5000 cycles. An solid-state hybrid supercapacitor (Gd–MX//AC) delivered an energy density of 25.8 Wh kg−1 and a high power density of 3000 W kg−1, while maintaining outstanding capacitance retention over repeated cycles.

Streszczenie:
The microscopic fate of dopants introduced under nonequilibrium conditions remains largely unresolved in wide-band gap oxides. Using temperature-dependent N K-edge X-ray absorption spectroscopy, we directly resolve the local bonding configuration of implanted nitrogen in (100) β-Ga2O3. The spectra are dominated by a sharp π* resonance characteristic of N≡N bonding that systematically intensifies upon annealing, providing a direct spectroscopic fingerprint of molecular nitrogen formation. First-principles calculations and multiple-scattering simulations reproduce these spectral features and identify molecular N2 as the dominant dopant state. Rather than forming substitutional acceptors, implanted nitrogen evolves toward N2-like configurations stabilized in defect-rich environments associated with local β→γ-like structural motifs. This behavior reflects a thermally driven reconfiguration of nitrogen within the damaged layer. These results demonstrate that dopant incorporation can proceed via molecularization pathways that bypass conventional substitutional doping, providing a general mechanism for dopant deactivation under nonequilibrium incorporation conditions in oxides.

Streszczenie:
Targeted and on-demand drug delivery technologies have attracted considerable interest for personalized cancer therapies. In this study, we developed a UV-crosslinkable and thermo-responsive gelatin methacrylate (GelMa)—poly(N-isopropylacrylamide) (PNIPAM) (G/P) hybrid hydrogel, integrated with folic acid-functionalized superparamagnetic iron oxide nanoparticles (SPIONs). Differential scanning calorimetry (DSC) and alternating magnetic field (AMF) evaluations confirmed that introducing GelMa modulated the lower critical solution temperature (LCST) to approximately 32 °C while enabling efficient magnetothermal response. Cyclic compression tests demonstrated superior mechanical properties. The 2.5G/P hydrogel achieved a compressive strength of 0.06 MPa at 78% strain, outperforming pure GelMa (0.023 MPa) and PNIPAM (0.012 MPa), with the highest modulus of elasticity at both 25 and 37 °C. In vitro biocompatibility assays using L929 fibroblasts indicated excellent cytocompatibility with >70% viability over 7 days. Furthermore, the hydrogel demonstrated excellent blood compatibility with a hemolysis ratio below 2%, complying with ISO 10993-4 standards. Synergistic reduction in cell viability was observed in human lung adenocarcinoma (NCI-H1975) and fibroblast-like osteosarcoma (MG-63) cell lines when combining drug loading and simulated AMF thermal stimulation. Triggered by hyperthermia at 41 °C, the hydrogel demonstrated a highly controlled, pulsatile ‘ON/OFF’ drug release profile of 5-fluorouracil (5-FU) driven by network shrinkage, achieving a maximum cumulative release of 72.6% over 28 days with a well-defined biphasic kinetic pattern. These results show that this dual-stimuli responsive hydrogel is a mechanically robust, highly efficient platform for controlled cancer therapy.

Słowa kluczowe:
UV-crosslinkable hydrogels, thermo-magnetic responsive hydrogels, cancer-targeting nanoplatforms, superparamagnetic iron oxide nanoparticles (SPIONs), AMF-triggered drug release, biocompatibility

Streszczenie:
Urea-assisted electrolysis boosts hydrogen production by substituting the sluggish oxygen evolution reaction (OER) with the energetically favorable urea oxidation reaction (UOR), thereby lowering energy consumption. Rational heterojunction engineering modulates charge distribution and generates abundant active sites, facilitating urea adsorption and C─N bond cleavage. Herein, we report a facile electrodeposition strategy to construct g-C3N4/CoMoS2 hybrid electrocatalysts. The built-in electric field at the heterojunction creates electrophilic regions on g-C3N4 and nucleophilic regions on CoMoS2, selectively activating urea and promoting rapid bond cleavage. Anchoring g-C3N4 onto CoMoS2 enables remarkable bifunctional activity toward both UOR and HER, achieving potentials of 1.27 V vs. RHE in 1 m KOH + 0.33 m urea and -80 mV vs. RHE in 1 m KOH at 10 mA cm−2, respectively. Density functional theory (DFT) calculations reveal that interfacial electron transfer enriches CoMoS2 with electrons and depletes g-C3N4, enhancing charge transfer, optimizing urea adsorption, and lowering reaction energy barriers. Notably, the g-C3N4/CoMoS2//g-C3N4/CoMoS2 cell delivers 10 mA cm−2 at 1.34 V with excellent stability, demonstrating superior efficiency. This work provides a rational framework for designing efficient, energy-saving urea-assisted hydrogen production systems and reveals how intrinsic electric fields can precisely control charge distribution during catalysis.

Słowa kluczowe:
built-in electric field, heterojunction, hydrogen production, urea oxidation

Streszczenie:
Accurate assessment of lithium-ion battery ageing is complicated by cell-to-cell variability, heterogeneous cycling protocols, and limited transferability of data-driven predictors. This study develops a continuous ageing-trajectory framework in which coordinate-based multilayer perceptron (MLP) and sinusoidal representation network (SIREN) models represent state-of-health and voltage–capacity trajectories as differentiable
functions of normalized trajectory coordinates. The framework combines continuous reconstruction, derivativebased knee descriptors, equivalent-full-cycle (EFC) harmonization, protocol-held-out early-life prediction, perturbation analysis, and conformal uncertainty quantification. Early-life prediction was evaluated in four protocol-held-out folds, repeated for three random seeds, using the first

Słowa kluczowe:
Lithium-ion batteries, Battery ageing, Implicit neural representations, State of health, Remaining useful life, Knee-point detection, Cross-protocol validation, Reliability analysis

Streszczenie:
This work presents a combined experimental and numerical investigation of local overheating in NiAl during spark plasma sintering (SPS). Experimental studies were conducted on samples sintered under different temperature and pressure conditions to capture both the early and final stages of densification. Both perpendicular and parallel loading directions were analysed for microstructural evidence of local melting. Experimental research comprised post-process analysis using SEM and EBSD, while supplementary XRD analysis was used to assess phase stability and crystallographic characteristics. Microstructural analysis focused on regions most susceptible to overheating (contact areas, small particles trapped between larger ones). Sintered samples showed progressive densification, neck growth and grain coarsening with increasing temperature. EBSD maps of sintered compacts reveal distinct orientations across contacts, with no evidence of epitaxial or equiaxed grain growth. Experimentally, no evidence of melting due to local overheating was detected. The experimental observations were complemented by particle-scale thermo-electric FEM simulations. Geometries of equal-sized particles, arranged in a straight line and in a zig-zag chain, connected by the necks with increased resistance, were considered to analyse the temperature rise in the necks. Geometry consisting of a small particle between two large particles was analysed to assess temperature nonuniformity in heterogeneous microstructures. The results show temperature increase in contacts or in small particles; however, the resulting temperature differences are less than 1 C in all cases studied. Numerical results support the experimental findings that NiAl is not prone to local overheating in SPS under the studied conditions.

Streszczenie:
The urea oxidation reaction (UOR) offers a sustainable and thermodynamically favorable alternative to the oxygen evolution reaction, enabling coupling of urea-rich wastewater remediation with energy-efficient hydrogen production. However, the sluggish six-electron-transfer kinetics of UOR necessitate advanced electrocatalysts to accelerate reaction dynamics. Heterostructure engineering provides an effective strategy to regulate interfacial charge redistribution and enhance catalytic activity. Herein, we report a rationally designed MoS2/Ni3Se2 heterostructure with an intrinsic built-in electric field, constructed on nickel foam via hydrothermal growth followed by electrodeposition, exhibiting efficient bifunctional electrocatalytic activity toward UOR and the hydrogen evolution reaction. Density functional theory calculations reveal spontaneous interfacial charge transfer at the MoS2/Ni3Se2 interface, generating localized electrophilic and nucleophilic regions that facilitate urea adsorption, promote bond activation, and accelerate decomposition kinetics. Benefiting from this interfacial electronic modulation, the catalyst requires only 1.20 V vs. RHE to achieve 10 mA cm−2 for UOR in 1 M KOH + 0.5 M urea and an overpotential of 81 mV to reach the same current density for HER in 1 M KOH. Furthermore, the assembled UOR//HER electrolyzer operates at 1.31 V at 10 mA cm−2 and maintains stable performance for over 100 h. This work advances heterostructure-based urea-assisted hydrogen production for sustainable electrocatalysis.

Słowa kluczowe:
built-in electric field, electrocatalysis, hydrogen production, MoS2/Ni3Se2 heterostructure, urea oxidation reaction

Streszczenie:
The human skin is highly susceptible to bacterial infections and inflammation when its integrity is disrupted. Treatment of infected wounds is a big challenge in modern medicine, and rising antibiotic resistance motivates the development of antibiotic-free therapies. Here, we present a stimuli-responsive wound dressing that integrates carboxylated eggshell membrane (ESM) with electrosprayed tannic acid/iron (TAFe) particles trapped between electrospun Poly-L-lactide-caprolactone (PLCL) layers and precisely laser-structured to increase porosity and fit the wound size. The TAFe exhibits stable photothermal conversion and antioxidant activity, eradicating more than 99.5% of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), while maintaining high biocompatibility in vitro. In an infected rat model, the sandwich-like ESMmod/PLCL/TAFe dressing accelerated closure and achieved near-complete healing, with residual wound area <1% by day 14. Analysis shows that the material promotes M2-mediated reparative microenvironment, which, in consequence, suppresses TNFα and IL-6, a pro-inflammatory cytokines, and enhances angiogenesis through increased CD31 and VEGF levels. Moreover, a more organized collagen structure and less scarring were found in the wound bed. Importantly, the material is partially derived from waste, aligning with circular economy principles and reducing resource burden. The versatile composite offers an antibiotic-free strategy that disinfects, modulates inflammation, and promotes regeneration of infected wounds.

Słowa kluczowe:
circular economy, immunomodulated wound healing, laser-engineered microenvironment, macrophage polarization orchestration, photothermal anti-bacterial activity

Streszczenie:
Reliable assessment of rheumatoid arthritis (RA) using infrared thermography requires a measurement framework capable of characterizing the dynamic thermal response to controlled excitation while limiting sensitivity to acquisition conditions, inter-subject variability, and computational instability. This study presents a measurement-oriented Active Dynamic Thermography (ADT) framework in which a dual-stream late-fusion stage combines radiomic descriptors with convolutional representations of the acquired thermal response. The
measurand was defined as the spatio-temporal thermal response of the hand during post-stimulus rewarming, interpreted as an indirect functional indicator of superficial microvascular and subcutaneous vascularbed activity associated with inflammatory processes. Controlled cold excitation provided a standardized thermal perturbation for observing vascular recovery dynamics, while radiometric verification and protocol
standardization were used to reduce non-biological acquisition variability.
The proposed framework was evaluated on thermographic recordings acquired from 187 patients with clinically confirmed RA and 292 healthy controls. To assess the robustness of the diagnostic output to cohort partitioning, experiments were repeated across ten independent subject-disjoint realizations. FUSION achieved a mean accuracy of 91.0%, balanced accuracy of 91.4%, Matthews correlation coefficient (MCC) of 0.819, ROC-AUC of 0.954, and PR-AUC of 0.901. Compared with the evaluated standalone baselines, FUSION showed higher mean performance and lower descriptive inter-seed variability. Ranking and distributional
analyses suggested improved stability. Paired Wilcoxon comparisons showed significant improvements over the standalone CNN baseline for several discriminative metrics after adjustment, whereas differences relative to the stronger INR baseline did not reach the adjusted significance threshold.
The results support the feasibility of a measurement-oriented ADT framework in which complementary thermal descriptors are integrated within a computational decision stage. The fusion component should therefore be interpreted as part of the broader thermal measurement chain rather than as the measurement principle itself. Further test-retest, inter-device, and external validation is required to establish physical repeatability, reproducibility, and clinical generalizability.

Słowa kluczowe:
Metrology, Infrared thermography, Sensor fusion, Measurement stability, Calibration, Radiomics, Rheumatoid arthritis

Streszczenie:
This communication introduces the protocol for the fabrication of PVA/PEO/alginate sulfate electrospun mats cross-linked using a green, non-toxic, and gentle freeze-thaw approach. We present the electrospinning solution composition that yields homogenous, bead-free fibres that cross-link tightly during repeated cycles of freezing and thawing, producing a hydrogel-like mat that is stable for at least 4 weeks in aqueous conditions at 37 °C.

Streszczenie:
Physical virology investigates viral particles by focusing on their assembly, stability, mechanics, and interactions with host cells, neutralizing antibodies, and surfaces. Within this field, computational virology is becoming an indispensable pillar, serving as a “computational microscope” that bridges the spatio-temporal scales of viral processes, from individual protein dynamics to capsid assembly and cellular entry. This perspective article offers a critical overview of the current state, challenges, and future directions of computational approaches in physical virology. Our vision is anchored in the research presented at the 2025 EMBO/FEBS Lecture Course on Physical Virology held in Sant Feliu de Guixols, Spain, and complemented by a targeted survey among attendees. We survey the principal methodological frameworks in use, from all-atom to multiscale molecular simulations, mesoscale simulations, and growing integration of artificial intelligence (AI) tools. We also critically examine the central obstacles impeding the field’s progress, including the computational-experimental gap, limited accessibility to simulation data, reproducibility concerns, and systemic gender and geographic inequities. Finally, we outline future perspectives, proposing that integrating physics-aware AI with multiscale simulation frameworks, combined with community-driven data-sharing initiatives, will transform the computational microscope from a descriptive tool into a predictive engine for antiviral therapies, rational vaccine design, and biotechnological innovation.

Słowa kluczowe:
Virion, Physical Viriology, MD, Coarse-Grainded MD, Proteins, Biomolecules, Continuum methods, PB, SIRAH, GoMartini, Nanobodies, SARS-CoV-2

Streszczenie:
In practical applications, MXenes are often subjected to a variety of loads, including compression. While their mechanical response under different loading conditions, such as tensile loading, has been extensively studied, their compressive instability remains largely unexplored. The compressive and post-buckling behavior of Ti2C and Ti2CO2 MXene nanosheets is studied using molecular dynamics (MD) simulations and a nonlocal formulation. The employed interatomic potential is first validated against experimental and density functional theory (DFT) data for structural and mechanical properties. The results indicate that classical continuum mechanics underestimates the buckling strains, whereas the nonlocal formulation adequately captures the observed response. A systematic examination of various defect types up to a defect fraction of 3% reveals that while isolated point defects primarily reduce the critical buckling stress, vacancy clusters significantly alter the buckling mode shapes. Lateral confinement pressure and oxygen surface termination substantially increase the buckling stress. Atomistic analysis reveals opposite stress states in the top and bottom Ti layers due to curvature-induced strain gradients. Under biaxial compression, the nanosheet buckles in a dome-like shape, whereas shear loads produce elliptical deflection modes. The presented findings may stimulate future studies on MXene morphological transformations, such as the development of nanotube, nanoscroll, and folded architectures.

Streszczenie:
Mucosa can be found in the eyes, oral cavity, bladder, vagina, airways, and gastrointestinal tract. It is an attractive route of administration for systemic or topical delivery of therapeutics. However, the mucus layer acts as a protective barrier, limiting the amount of biomolecules that reach the underlying epithelium. Mucoadhesion, mucodiffusion, and mucolysis are well-established mucointeractive strategies that can improve therapeutic outcomes, but due to their individual limitations, the resulting delivery is often still unsatisfactory. In recent years, drug delivery systems have emerged that combine multiple mucointeractive strategies, which we define here as hybrid mucointeractive delivery systems. This work aims to provide a general overview of such drug delivery systems, which include particle-releasing macrostructures such as gels, foams, films, and fibers, as well as systems such as zeta potential-changing particles and self-emulsifying drug delivery systems. Their potential, possible future, and limitations are discussed as well.

Słowa kluczowe:
mucoadhesion, mucopenetration, mucolysis, drug delivery, mucosa, transmucosal, polymers, nanoparticles, nanotechnology

Streszczenie:
In this work, the very-high-cycle fatigue (VHCF) response of 10H2M steel in the as-received state and after 280,000 hours of service at 540 °C under pressure was analysed. Although after prolonged service, only a moderate decrease in yield strength was observed, fatigue performance was significantly reduced in the stress range applied. Fractographic analysis revealed that in both material states, fatigue cracks initiated near the surface, with carbides acting as preferential nucleation sites. In the as-received material, cracks propagated in a relatively uniform, transgranular manner with ductile overload fracture at final failure. In contrast, the prolonged-service material exhibited rougher fracture surfaces with more frequent crack deflections and secondary cracking, linked to carbide coarsening due to service. The results demonstrate that prolonged exposure does not fundamentally change the surface-dominated initiation mechanism but intensifies the role of carbides and boundary-related defects, thereby reducing fatigue resistance. EBSD-informed finite-element representative volume element (RVE) simulations further revealed that prolonged service exposure increased the local carbide/matrix stress concentration factor, providing micromechanical evidence for the experimentally observed deterioration in fatigue resistance. Additionally, X-ray diffraction (XRD) analysis confirmed thermodynamically driven carbide precipitation and crystallographic evolution, characterised by reduced carbon supersaturation, crystallite refinement, residual micro-stress relaxation and texture evolution following long-term service exposure.

Słowa kluczowe:
Very high cycle fatigue, Power plant steels , Failure mechanisms , Ultrasonic testing

Streszczenie:
RNA is a flexible biopolymer that adopts diverse conformations while forming structural motifs essential for its function. Classical RNA force fields often show limited transferability and inefficient sampling of transitions between stable states, particularly in moderately large RNA. To address these limitations, quantum-informed machine learning (ML) potentials have recently emerged as a promising alternative, offering improved accuracy and transferability relative to classical force fields. Here, we assess ML potentials for exploring RNA conformations using the adenine–adenine dinucleoside monophosphate (ApA) dimer, a fundamental RNA building block. We generated an extensive quantum-mechanical (QM) dataset of physicochemical properties for ApA conformations obtained from temperature replica exchange molecular dynamics (TREMD) simulations. Despite its small size, the ApA dimer exhibits a complex energetic landscape with six well-defined conformational clusters in which quantum effects and solvent-mediated interactions play a crucial role. Using this dataset, we parametrized ML potentials based on the equivariant MACE architecture and informed by both ab initio and semiempirical property data. The resulting potentials reproduce key conformational features of the ApA system, including base stacking, sugar geometry, and backbone flexibility, and provide broader coverage of structural transitions than the general-purpose SO3LR and MACE-POLAR-1 models. These findings underscore the importance of comprehensive QM datasets for RNA building blocks to support the structural and energetic characterization of RNA complexes and emphasize the need for robust and efficient validation metrics for ML potentials.

Słowa kluczowe:
Machine Learning, RNA, Free Energy, Conformational Changes , MD, Genetics, Cluster Analysis, Molecular Mechanics

Streszczenie:
Impulse face seals (IFS) are critical components of pumping and compressor equipment operating under high pressures, rotational speeds, and severe thermal and tribological conditions. The durability and reliability of IFS are largely governed by the properties of their working face surfaces, which motivates the development of advanced surface modification technologies. This study investigates the formation of nanostructured surface layers on Armco iron and HS6-5-2 tool steel by electrospark alloying (ESA) with a special technological medium (STM) containing single-walled carbon nanotubes (CNTs). The proposed processing route involved sequential ESA with a molybdenum electrode, application of CNT-containing STM, repeated ESA. The coatings were characterized in terms of microstructure, elemental distribution, surface roughness, microhardness, and wear resistance. Tribological tests were conducted under end-face friction against fluoroplastic, and real-life tests of an impulse gas face seal were performed to evaluate operational performance. The results demonstrate that adding 0.01 wt% CNTs to STM significantly refines the microstructure. A nanostructured coating with a microhardness of up to 1650 HV (for HS6-5-2 steel) was obtained, demonstrating more than a threefold improvement in wear resistance compared to coatings produced without the STM. Real-life tests confirmed stable sealing performance, low leakage, and a favourable thermal regime. The proposed ESA nanostructuring approach effectively improves the wear resistance and service life of impulse face seals in high-load compressors.

Słowa kluczowe:
Electrospark alloying, Special technological medium, Carbon nanotubes, Coating, Microstructure, Wear resistance, Impulse face seals, Real-life tests

Streszczenie:
Concrete shielding structures in nuclear facilities must maintain both radiation attenuation capacity and transport barrier performance throughout their service life. Although gas permeability and radiation shielding properties have been widely investigated, their coupled evolution under load-induced damage remains insufficiently understood, particularly for concretes with low-clinker cements. This study evaluates the combined effects of low-clinker cement type, aggregate type, and mechanical preloading on the gas permeability and gamma-ray shielding performance of concretes intended for nuclear applications. Six mixtures were produced using CEM II/C-M (V–F–LL) and CEM V/A (S–V) cements combined with magnetite, basalt or limestone aggregates. Gas permeability was measured using the Cembureau method on specimens subjected to progressive preloading up to 90% of the splitting tensile strength. Gamma-ray attenuation parameters were determined using a 137Cs source (0.662 MeV), and microstructural observations were performed by SEM. Aggregate type was the dominant factor governing shielding performance. Magnetite concretes exhibited the highest compressive strength, the lowest gas permeability, and the highest attenuation coefficients, reaching μ = 0.258 cm⁻¹ and HVL = 2.68 cm. CEM V concretes generally showed lower permeability than the corresponding CEM II concretes. Mechanical preloading increased gas permeability, particularly above approximately 80% of the splitting tensile strength, indicating the formation of connected microcrack networks. Simultaneously, a reduction in attenuation factor was observed, demonstrating that load-induced damage adversely affected shielding effectiveness. A relationship between the increase in permeability and the reduction in attenuation factor was identified, suggesting a transition from pore-controlled to crack-controlled behaviour. The results demonstrate the suitability of concretes with low-clinker cements for shielding applications and provide new insight into the coupling between damage development, transport properties, and radiation shielding performance.

Słowa kluczowe:
Permeability, Shielding concreto, Load, Microstructure, Low-clinker cement, Gamma-ray attenuation, Microcracking

Streszczenie:
Essential parameters characterizing the behavior of hyaluronan molecules in electrolyte solutions were determined by combining multiscale theoretical modeling with comprehensive experimental investigations. Atomistic molecular dynamics simulations yielded the molecule density, chain diameter and disaccharide length. For the first time, coarse-grained Monte Carlo simulations were applied to analyze chains of realistic lengths, explicitly accounting for long-range electrostatic interactions controlled by solution ionic strength. Physicochemical parameters, including diffusion coefficient, hydrodynamic diameter and electrophoretic mobility, were experimentally determined for various NaCl concentrations. From these data, we derived electrokinetic charge and effective ionization degree of hyaluronan. It was reported that the dissociation degree of hyaluronan molecules amounts to only 20 % at 0.0001 M and 7.8 % at 0.15 M. This effect was interpreted in terms of charge compensation by counter-ion adsorption, in agreement with simulation results and consistent with the Manning ion condensation theory. Furthermore, dynamic viscosity measurements, interpreted via intrinsic viscosity and Einstein viscosity increment, provided insights into the conformational features of the molecule. Correlating experimental findings with theoretical predictions, it was shown that hyaluronan chains adopt extended conformations at low ionic strength, driven by electrostatic repulsions between glucuronic acid residues, leading to a marked increase in intrinsic viscosity compared to physiological conditions. Therefore, these results advance the understanding of hyaluronan molecular dynamics and establish a novel methodology for a precise determination of its molar mass, overcoming the limitations of conventional viscometric approaches that require calibration and external standards.

Słowa kluczowe:
Hyaluronan, Electrokinetic charge, Hydrodynamic properties, Intrinsic viscosity, Molecular modeling, Molecular conformation

Streszczenie:
The nonlinear primary resonant dynamics of ternary polymethyl methacrylate (PMMA) nanocomposite microbeams reinforced with carbon nanofibers (CNFs) and silicon carbide (SiC) nanoparticles are explored using a multiscale computational framework that combines a finite element-based micromechanical homogenization with size-dependent continuum modeling, thereby establishing a direct connection between the microscale material architecture and nonlinear dynamic performance. Accordingly, the roles of key nanoscale design parameters on the size-dependent nonlinear resonant behavior are systematically elucidated. Specifically, the influence of CNF volume fraction and aspect ratio, SiC nanoparticle volume fraction and diameter, interphase properties, and nanofiller dispersion are assessed to reveal their individual contributions to the resonant response. To achieve this objective, the effective elastic properties of the ternary nanocomposite are first extracted through a numerical homogenization of three-dimensional representative volume elements and subsequently incorporated into the modified strain gradient and classical continuum beam models for nonlinear dynamic analysis. It is deduced that increasing the CNF aspect ratio enhances the effective stiffness of the ternary nanocomposite, although the reinforcing effect gradually saturates at larger aspect ratios. In contrast, increasing the SiC nanoparticle diameter reduces the mechanical properties, shifting the resonance curves toward lower excitation frequencies and increasing peak vibration amplitudes. Also, it is observed that when the interphase modulus is lower than that of the PMMA matrix, the interphase acts as a compliant layer, limiting the effective transmission of stresses from the matrix to the reinforcing nanofibers. As the interphase modulus exceeds that of the polymer matrix, the stiffness mismatch between the CNFs and the surrounding medium decreases, leading to a significant improvement in load transfer efficiency and a noticeable reduction in the softening-type nonlinearity

Słowa kluczowe:
Nonlinear resonance, Micromechanical modeling, Size dependency, Ternary nanocomposites, Numerical solution

Streszczenie:
In order to utilise NiTi shape memory alloys in environments with extreme radiation, it is essential to understand how irradiation affects their superelastic properties on a nanoscale level. We use a spherical nanoindentation technique in two perpendicular directions, combined with indentation work analysis to evaluate the nanoscale superelastic behavior and functional degradation of Fe+ ion irradiated NiTi. Cross-sectional nanoindentation reveals that the maximum hardening and the lowest superelastic response occur near the depth of peak Fe⁺ concentration (2.6–2.8 μm). Importantly, the superelastic behavior exhibits a non-monotonic dependence on damage level: complete loss of superelastic recovery is observed at 1.7 d.p.a., whereas partial recovery reappears at 8.5 d.p.a., indicating a competition between lattice amorphization and irradiation-mediated. Using cross-sectional nanoindentation, we can capture variations in stiffness and recoverable work at the nanoscale, as a function of depth, that cannot be resolved using conventional surface indentation methods. We conclude that ion irradiation leads to significant hardening and suppression of superelasticity phenomena due to inhibition of the stress-induced B2→B19′ martensitic transformation. These findings demonstrate that two-directional spherical nanoindentation is an effective approach for probing irradiation-induced functional gradients.

Słowa kluczowe:
NiTi SMA, Ion irradiation, Superelasticity, Indentation, Indentation work, Surface modification

Streszczenie:
Multilayered aluminum-matrix composites constitute a subclass of functionally graded materials whose mechanical properties can be systematically tailored to meet specific design requirements. In this study, experimental and numerical investigations are performed to characterize Mode I and mixed-mode I/II fracture behavior and crack growth in graded AlSi12–Al2O3 composites containing a notch oriented along the gradient direction. Mode I fracture tests are conducted on four-layer, disk-shaped compact specimens subjected to tensile loading, with Al2O3 volume fractions of 0 (pure matrix), 10, 20, and 30 percent. Crack propagation on both specimen surfaces is monitored in situ, and full-field displacement measurements are obtained using Digital Image Correlation. The experiments reveal a pronounced nonlinear crack-front propagation induced by material composition gradient along the crack front. Fracture consistently initiates in the layer with the highest content of ceramic particles, propagates within this layer, and subsequently extends into adjacent layers. Distinct fracture surface morphologies are observed using scanning electron microscopy, ranging from brittle features in ceramic-rich layers to progressively more ductile characteristics in layers with lower ceramic content. An elastic–plastic phase-field model is employed to examine the influence of stacking sequence on fracture load capacity as well as on crack-front formation and evolution under both Mode I and mixed-mode I/II loading conditions. The phase-field model is calibrated against experimentally measured fracture loads, and the characteristic length-scale parameter is identified accordingly. The simulations successfully reproduce the experimentally observed nonlinear crack-front morphology and demonstrate that the stacking sequence considerably affects the maximum load-bearing capacity and crack front geometry under both pure Mode I and mixed-mode loading.

Słowa kluczowe:
Metal-matrix composite, Multilayered structure, Nonlinear crack front, Fracture load, Stacking sequence, Phase-field modeling

Streszczenie:
For efficient alkaline water-splitting, it is crucial to have bifunctional electrocatalysts that exhibit low overpotentials, durability, and the possibility of being produced through scalable methods. This study involved the use of screen printing to apply a porous nickel microparticle/polymer interlayer onto commercial nickel foam, which then acted as a base for the solvothermal growth of cobalt-based oxide/hydroxide nanostructures. The optimized electrode showed excellent bifunctional capabilities in 1 M KOH, requiring only 61 mV for the hydrogen evolution reaction and 241 mV for the oxygen evolution reaction at a current density of 10 mA cm−2. In comparison, the control electrodes, such as those with cobalt directly deposited on unmodified nickel foam and screen-printed nickel foam substrates without cobalt, exhibited poorer overall performance. Although the cobalt-modified nickel foam exhibited a higher Cdl-derived apparent electrochemical surface area, the cobalt-modified screen-printed electrode achieved the best ECSA-normalized HER and OER responses, indicating that the enhancement in activity was not solely due to the capacitive surface area of the electrode. The increased integrated redox charge suggests a greater contribution from electrochemically accessible Co/Ni redox-active species, while impedance analysis supports a more favorable apparent interfacial response under the tested HER- and OER-relevant conditions. Long-term chronopotentiometry and post-stability SEM confirmed stable bifunctional operation.

Słowa kluczowe:
alkaline water splitting, bifunctional electrocatalyst, HER/OER, nickel foam, screen printing

Streszczenie:
Anisotropic yield criteria and kinematic hardening laws have been independently validated for additively manufactured alloys. However, their specific combination has not been implemented in a finite element user subroutine and validated against 360° sequential biaxial probing data for LENS-deposited nickel-base alloys. Present work delivers the first validated implementation of this coupling for LENS-deposited Inconel 625, combining the Szczepiński quadratic yield criterion with Armstrong–Frederick kinematic hardening. The implemented return-mapping algorithm accumulates the plastic multiplier across Newton–Raphson iterations before updating the plastic and equivalent plastic strain state variables. This distinction is significant for the non-radially-symmetric Szczepiński surface where the flow direction rotates at each iteration unlike the fixed radial direction of isotropic return mapping. A two-step iterative boundary-condition correction scheme ensures each probing direction converges within ±1.5° of the experimental stress angle, achieved for 16 of 17 sequential paths. Path P1, the virgin specimen opening probe retains a residual angular deviation of −2.97° due to absent accumulated back-stress at the start of the sequential cycle. The validated UMAT reproduces all 17 directional yield points with a mean absolute angular error of 0.86°, mean absolute axial and shear stress deviations of 11.4 MPa and 12.5 MPa, respectively. Path-level deviations reach a maximum of 32 MPa in axial stress at P10 and 41.4 MPa in shear stress at P5, attributed to angular misalignment between back-stress and probing direction in the compressive–shear and near-pure-torsion sectors, respectively. This establishes the framework as a computational tool for characterising multiaxial yield surface under complex loading.

Słowa kluczowe:
Inconel 625, Anisotropic yield Surface, Szczepiński yield criterion, User subroutine, Kinematic hardening, Sequential multiaxial loading

Streszczenie:
The effect of spatial distribution of randomly-placed particles in a representative composite volume on the thermoelastic effective properties and local stress and strain distribution is analyzed. Quantitative assessment is performed using both the full-field finite element analyses and the mean-field interaction model, known also as a “cluster” model. The latter model is developed in the multi-family setting enabling one to study the mean stress and strain separately for each inclusion in the representative unit cell. The particles are assumed to be spherical and of equal size, while considered examples differ by the volume fraction of inclusions and the particle spatial layout, and in particular the mean nearest-neighbour distances.

Słowa kluczowe:
Composite materials , Thermoelasticity, Micro-mechanics, Packing and spatial distribution effects

Streszczenie:
Nickel–iron-layered double hydroxides (NiFe-LDH) are known for their strong electrochemical activity and low cost, yet their practical use in energy-storage devices is restricted by limited electrical conductivity and sluggish ion transport. To address these limitations, conductive additives are commonly incorporated into hydroxide frameworks to enhance charge mobility and overall electrochemical response. In this study, a binder-free NiFe-LDH/Ti3C2Tₓ MXene nanocomposite was fabricated through a hydrothermal synthesis route and then applied as a supercapacitor electrode. Material characterization results confirmed the successful formation of NiFe-LDH with uniformly dispersed MXene sheets, yielding a nanoflower-like hierarchical structure. Such architecture increased the accessible surface area and generated a highly porous network, both of which promoted efficient electrochemical reactions. Electrochemical evaluation of the prepared electrode revealed a specific capacitance of 1512 F g−1 at 0.75 A g−1, along with strong rate performance. Furthermore, the assembled asymmetric supercapacitor delivered an energy density of 47.25 Wh kg−1 and a power density of 700 W kg−1, while retaining 65% of its capacitance after 10,000 charge–discharge cycles. The performance was improved compared to previous work on NiFe LDH due to strong interfacial coupling between LDH nanosheets and functionalized MXene surfaces.

Streszczenie:
Advances in structural biology, particularly cryo-electron microscopy, have enabled high-resolution characterization of complex protein assemblies. These developments underscore the need for computational approaches capable of describing biologically relevant conformational changes over extended timescales. GōMartini 3 is a coarse-grained approach that demonstrates computational efficiency and versatility across several systems, from membrane-binding proteins and soluble proteins to intrinsically disordered proteins, while preserving key physicochemical features. In this work, we introduce an optimized approach that integrates dynamic contact information from all-atom molecular dynamics (AA-MD) simulations to refine the contact map in GōMartini simulations and select the AA-MD structure consistent with the refined map. Specifically, we define high-frequency contacts, which reduce the number of original Gō contact set by ≈20%–30%, thereby improving the representation of conformational states beyond the original approach in Martini 3. Benchmarking different contact selection criteria revealed that including intra- and interchain high-frequency contacts in protein assemblies captures structural flexibility and domain dynamics. The method was tested on single-chain globular proteins and on the SARS-CoV-2 spike protein. Overall, the optimized contact map improves sampling efficiency and expands the accessible conformational landscape. The full framework is available as an open-source tool for large-scale simulations of protein assemblies.

Słowa kluczowe:
GōMartini 3 , Molecular Simulation, Proteins, Biomolecular Ensemble, Free Energy, Coarse-graining, cryo-electron microscopy

Streszczenie:
Surface modification of scaffolds is a topic of great interest in tissue engineering due to the crucial role of scaffold surface in interactions with cells. In this study, we characterize electrospun poly(caprolactone) (PCL) nonwoven mats coated with silk fibroin (SF) protein, gelatin, and combined SF-gelatin coating in the context of material properties and response of human osteoblast-like (MG-63) cells. We compare two methods of protein attachment to aminolyzed PCL fibers: chemical one, namely carbodiimide coupling, and electrostatic layer-by-layer deposition. Five different types of coatings were studied, including separate coatings of SF and gelatin, as well as combined coatings. To enable both types of modification, additional –COOH and –NH2 groups were introduced into the SF by chemical modification. The protein immobilization processes did not change the morphology and diameter of the PCL fibers. As a result of all modifications, hydrophobic PCL scaffolds became wettable. Colorimetric bicinchoninic acid (BCA) assay on PCL fibers detected the immobilized proteins and revealed that carbodiimide coupling and layer-by-layer deposition of SF coatings resulted in a similar level of absorbance, indicating no difference in protein content. However, the chemically bound SF coating exhibited greater stability in phosphate-buffered saline (PBS) solution. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy analysis confirmed the immobilization of SF, gelatin, and SF-gelatin coatings on PCL fibers by the presence of amide I, amide II, and amide A bands. Analysis of the morphology and metabolic activity of osteoblast-like MG-63 cells on the modified scaffolds indicated that the SF coatings without the addition of gelatin provided the best outcomes in terms of cell adhesion and growth. These results indicate the predominance of SF properties over the effect of the bioactive RGD-sequence of gelatin.

Słowa kluczowe:
bone tissue, electrospinning, gelatin, osteoblasts, silk fibroin, surface modification

Streszczenie:
Bronzes are widely used as anti-friction materials in sliding units. However, their performance depends heavily on the condition and structure of the surface layer. This study investigates the formation of multilayer antifriction coatings on CuSn10Pb10 bronze by electrospark alloying (ESA) using silver, lead, and tin electrodes. ESA was conducted in a sulphur-containing technological medium. Two technological schemes were implemented: conventional multilayer alloying (Ag → Pb → Ag and Ag → Sn → Ag) and alloying using a sulphur-containing medium ((S + Ag) → Pb → (S + Ag) and (S + Ag) → Sn → (S + Ag)). The microstructure, microhardness, surface roughness, and elemental distribution in the formed layers were investigated using optical microscopy, scanning electron microscopy with energy-dispersive analysis, and microhardness measurements. The tribological properties of the coatings were evaluated using a ball-on-disk configuration. It was determined that ESA produces a multilayer structure consisting of an outer layer, a bright sublayer, a heat-affected zone, and the substrate. The bright sublayer exhibited the highest microhardness values due to intensive material mixing and rapid melt solidification. The lowest friction coefficients (µ = 0.095−0.148) were obtained for sulphur-containing coatings. Introducing sulphur reduces the friction force by an average of 19%, due to a decrease in the adhesive component of friction and suppression of contact seizure.

Słowa kluczowe:
electrospark alloying, sulphur-containing medium, bronze, multilayer coatings, tribological properties

Streszczenie:
Plasma nitriding is a promising method for enhancing the surface mechanical properties of compositionally complex alloys (CCAs), though the mechanisms governing phase evolution and property changes remain unclear. This study investigates the microstructural evolution and mechanical response of a Zr45Ti31.5Nb13.5Al10 alloy after plasma nitriding, combining experimental techniques with thermodynamic calculations. Mechanical properties were assessed via nanoindentation, including hardness, H/E, and H3/E2 ratios. Nitriding produces a chemically and structurally graded surface layer consisting of a near-surface FCC (B1-type) multicomponent nitride, a transition region with mixed FCC/HCP structure, and a BCC substrate. This gradient results from nitrogen diffusion and element-specific nitride formation, as confirmed by EBSD, TEM (SAED, EDS), and XRD analyses. Surface hardness increases more than fivefold, from ∼5 GPa to ∼28 GPa, due to a combination of nitride formation, solid-solution strengthening, and nanoscale microstructural refinement. The nitriding response is primarily controlled by strong nitride-forming elements (Zr, Ti, Nb), which facilitate uniform nitrogen incorporation and formation of a dense multicomponent nitride layer. Notably, aluminum is incorporated into the nitride lattice without forming a separate AlN phase. These results provide new insights into multicomponent nitride formation and highlight plasma nitriding as an effective strategy for tailoring surface properties of advanced CCAs.

Słowa kluczowe:
Compositionally complex alloys, Plasma nitriding, Multicomponent nitrides, Microstructure, Nanoindentation

Streszczenie:
In this study, a sound decay in two connected enclosed spaces was investigated. The research concerned the low-frequency range, because in this situation the sound decay is predominantly non-exponential. Numerical simulations were performed for a system of two connected rectangular subrooms. The larger subroom was highly reverberant, while the smaller subroom had walls that provided moderate sound damping. Simulation results showed that after switching off the harmonic source, a non-exponential behavior of sound decay is usually observed. This is because many eigenmodes are involved in the sound decay, hence this process strongly depends on both the source frequency and its position. Reverberant properties of the system were also determined using energy decay curves calculated by the reverse-time integration of the squared room impulse response. Simulations showed that the effect of the significant difference in sound absorption in subrooms is a wide range of modal reverberation time values, i.e., it is large for eigenmodes localized in a highly reverberant room and small for eigenmodes localized in a damped room. The analyzed room system is therefore characterized by an interesting feature resulting from the localization of eigenmodes. When the source is located in the larger subroom, slowly decaying modes localized in this subroom dominate the sound decay process. However, when the source is located in the smaller subroom, the sound decay in the larger subroom is much faster since non-localized modes with a shorter modal reverberation time are excited within this subroom.

Słowa kluczowe:
coupled spaces, sound decay, sound absorption, room impulse response, decay times, localization of eigenmodes, modal reverberation time

Streszczenie:
Nickel-based composites reinforced with nanosized and hybrid micro-/nanosized silicon carbide particles were fabricated using a processing route combining high-energy ball milling, spark plasma sintering (SPS), high-pressure torsion (HPT), and post-deformation annealing. The aim of this study was to establish the relationships between processing, microstructural evolution, and mechanical performance in Ni–SiC composites subjected to severe plastic deformation and subsequent heat treatment. Spark plasma sintering produced highly densified composites with a homogeneous distribution of the ceramic reinforcement and a refined nickel matrix. Detailed microstructural characterization revealed significant chemical and morphological evolution of the SiC reinforcement during SPS, including the formation of carbon-enriched shells around microsized particles and Ni–Si reaction products associated with nanosized reinforcement. High-pressure torsion resulted in a homogeneous ultrafine-grained microstructure accompanied by extensive grain refinement, fragmentation of microsized SiC particles, and redistribution of nanosized reinforcement throughout the matrix. These microstructural changes produced a substantial increase in hardness and tensile strength, but at the expense of tensile ductility after HPT. The Ni–hybridSiC composite achieved a tensile strength of 1526 MPa and an average microhardness of 720 HV after annealing at 300 °C, while its ultimate elongation remained approximately 0.59%. Thus, the principal mechanical benefit of the applied processing route is the development of ultrahigh strength and hardness rather than a balanced strength–ductility response. Among all investigated materials, the hybrid micro-/nano-SiC composite exhibited the most effective strengthening response, demonstrating the synergistic effect of bimodal reinforcement and severe plastic deformation on the development of ultrahigh-strength nickel-based composites.

Streszczenie:
Polysaccharide chain conformation and mechanical properties are governed by local conformational degrees of freedom, in particular the torsional states of glycosidic linkages. Understanding how local torsional energetics propagate into global chain stiffness is essential for interpreting experimental data and for the development and validation of carbohydrate-specific force fields. In this study, we systematically investigated the relationship between the energetic stability of anti-type glycosidic conformers and the global conformational properties of polysaccharide chains. Monte Carlo simulations based on a reduced coarse-grained model were performed for three glucans – amylose (containing α(1 → 4) linkages), curdlan (β(1 → 3)), and cellulose (β(1 → 4)) – by progressively penalizing anti-Φ and anti-Ψ torsional states over a wide energetic range. In addition, the heterogeneous polysaccharide hyaluronan was analyzed by selectively blocking specific torsional freedoms at its β(1 → 3) and β(1 → 4) linkages. The results reveal qualitatively different mechanical regimes depending on linkage topology. Amylose behaves as an entropy-dominated semiflexible coil, with stiffness controlled mainly by Ψ energetics and showing only modest, gradual stiffening. Curdlan is geometry-dominated and highly sensitive to Φ energetics, rapidly reaching a rigidity plateau. Cellulose exhibits a critical, highly nonlinear response, where suppression of Ψ conformers drives a transition to near rod-like behavior with persistence lengths increasing by orders of magnitude. Importantly, the experimentally observed stiffness ordering of glucans (amylose < curdlan < cellulose) is preserved for nearly all combinations of anti-conformer energy levels, indicating that qualitative mechanical trends are largely insensitive to the specific energetic parameterization. Comparison with experimental persistence lengths further suggests that the free-energy penalties of anti-Ψ conformers lie below 5 kJ/mol for amylose, at ca. 5 kJ/mol for anti-Φ in curdlan, and in the range of 5–10 kJ/mol for anti-Ψ in cellulose. Hyaluronan shows intermediate stiffness, with Ψ rotations at β(1 → 4) linkages acting as dominant mechanical control points. Overall, the study demonstrates that specific local torsional transitions play distinct mechanical roles, and that linkage geometry fundamentally determines how local conformational energetics translate into global polysaccharide stiffness.

Słowa kluczowe:
Polysaccharide conformation, Persistence length, Glycosidic linkage rotation, Monte Carlo simulation, Free energy maps

Streszczenie:
The influence of initial microstructure on the high-temperature oxidation behaviour of MAR-M247 nickel-based superalloy was investigated experimentally and supported by CALPHAD modelling. Fine-grained, coarse-grained, and columnar microstructures were produced by casting and oxidised in air at 900°C for 1–500 h. Oxide evolution was characterised by SEM/EDS and X-ray diffraction, while Thermo-Calc was used to predict equilibrium oxide stability. All microstructures exhibited the same overall oxidation sequence, with initial NiO and Cr2O3 formation followed by development of an Al2O3-rich external scale and a chromium-enriched subsurface region. Thus, the initial microstructure did not alter the fundamental oxidation mechanism but significantly affected oxidation kinetics and scale morphology. The higher grain-boundary density of the fine-grained microstructure promoted elemental transport and oxide nucleation, enabling earlier development of a more uniform protective scale. After 500 h, the oxide scale was thinnest for the fine-grained material (1.56 μm), compared with 1.67 μm for the columnar and 2.24 μm for the coarse-grained material.

Słowa kluczowe:
high‐temperature oxidation, microstructure, nickel‐based superalloys, oxide scale formation

Streszczenie:
The free transverse vibration of Rayleigh nanobeams resting on aWinkler-Pasternak two-parameter elastic foundation is investigated within the local/nonlocal stress-driven gradient (LNStressG) elasticity framework. The constitutive model incorporates three length-scale parameters—the nonlocal characteristic length LC, stress-gradient length scale Ll , and mixture parameter α—to capture both stiffness-stiffening and stiffnessweakening size-dependent responses within a thermodynamically consistent formulation. The model is validated against three independent benchmark solutions, achieving excellent agreementwith the reference results. Four model hierarchies are systematically examined for clamped–clamped and pinned–pinned boundary conditions: the classical Rayleigh beam, purely stress-driven nonlocal model, two-phase local/nonlocal stress-driven model, and full LNStressG model. TheWinkler and Pasternak parameters consistently increase stiffness, with the strongest influence observed in the fundamental mode of pinned–pinned beams and diminishing effects at higher modes as nonlocal constitutive stiffness dominates. The purely stress-driven nonlocal model exhibits exclusively stiffening behavior, whereas the full LNStressG model reveals competing effects: increasing LC stiffens the response, while increasing Ll softens it. Their relative influence depends on mode number, boundary condition, and α. The results provide insight into substrate–size-effect interactions in nanobeam resonators, mass sensors, and energy harvesters.

Słowa kluczowe:
Nanobeam, Free vibration, Local/nonlocal stress-driven gradient elasticity, Winkler–Pasternak elastic foundation, Size-dependent response, Stiffening, Weakening

Streszczenie:
As microplastics in water continue to pose a growing environmental challenge, it becomes more important to develop cost-effective and efficient methods for their capture. While separation techniques such as membranes and fibrous filters are highly effective, the majority of them are typically produced using fossil-based resources, contributing to plastic waste. The goal of this research is to develop an effective filter for microplastics filtration utilising exclusively sustainable materials while addressing known limitations of cellulose acetate electrospinning. Specifically, the feasibility and effects of electrospinning cellulose acetate non-wovens from an ethyl lactate-acetone solvent system were investigated. Both the polymeric solutions and the resulting materials were thoroughly characterised using SEM, porosimetry, tensile testing, rheometry, contact angles and conductometry. The obtained non-woven materials were tested as filters for PVC microplastic removal in a dead-end filtration setup. Different morphologies and parameters were observed with the changes in composition. Nonetheless, most of the filters showed great potential in the filtration of commercially available microplastics, effectively removing particles as small as 0.2 µm with over 90% efficiency overall. While the process requires further optimisation, solvent systems based on ethyl lactate emerges as a promising green alternative to acetone in electrospinning, offering a more sustainable approach to microplastic filtration.

Słowa kluczowe:
electrospinning, ethyl lactate, cellulose acetate nonwoven, microplastics removal, microfiltration

Streszczenie:
The rising demand for durable, high-power energy storage devices has driven the advancement of innovative electrode materials for modern supercapacitors. In this regard, microwave-assisted synthesis has emerged as a fast and energy-saving approach for producing nanocomposites with superior electrochemical features. In this work, Ce(OH)3-x wt%rGO (x = 5, 10, and 15) nanocomposites were prepared through a simple microwave-assisted route to enhance electrochemical efficiency in supercapacitor systems. Structural and morphological characterizations using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET) analysis confirm the effective incorporation of Ce(OH)3 with reduced graphene oxide (rGO) sheets, resulting in improved crystallinity, abundant defect sites, and larger surface area. Electrochemical testing in a three-electrode setup shows that the optimized CeG-10 electrode delivers a specific capacitance of 1229 F/g at 1 A/g, with strong rate capability and minimal internal resistance. Long-term cycling experiments demonstrate 92% capacitance retention after 10000 charge–discharge cycles, confirming excellent structural and electrochemical durability. Moreover, the fabricated supercapacitor device achieves an energy density of 49.46 Wh/kg at a power density of 1400 W/kg. These findings emphasize the promising potential of microwave-assisted Ce(OH)3-rGO nanocomposites as efficient electrode materials for next-generation energy storage technologies.

Streszczenie:
The accelerated growth of industries in modern society has triggered the release of toxic dyes into the environment, presenting a serious ecological risk and posing challenges for effective removal. The mixed-metal-based photodegradation of methyl orange dye (MOD) in aqueous medium is elucidated by degradation byproducts. This study reveals the synergistic effect of Bi2SrO4(BSO), g-C3N4 (g-CN) and graphene oxide (GO) in enhancing the photocatalytic performance of BSO photocatalyst. XRD analysis was performed to identify the crystalline phase of the nanocomposite, while the morphology of the BSO/g-CN/GO was examined by SEM analysis. UV analysis reveals the incorporation of the g-CN and GO in BSO, significantly enhancing the visible-light-absorption which is well-suited for efficient photodegradation. BSO/g-CN/GO displays markedly superior photocatalytic activity relative to BSO, g-CN and BSO/g-CN owing to its decreased band gap value. The photodegradation activity of the prepared composite is evaluated via degrading MOD under stimulated to visible light conditions. The nanocomposite BSO/g-CN/GO demonstrates the phenomenal performance (93.5%) in the degradation of the MOD compared to the pristine materials. This significant improvement in performance is due to the formation of the S-scheme heterojunction. In essence, this study delivers new insights into the photocatalytic performance of the BSO/g-CN/GO underscoring its potential as a proficient photocatalyst for resolving environmental concerns.

Słowa kluczowe:
Photocatalysis, Bi2SrO4, g-C3N4, Graphene Oxide, S-scheme, Methyl Orange

Streszczenie:
Conducting polymers are widely explored as supercapacitor electrodes due to their reversible redox activity, electrical conductivity, and mechanical flexibility; however, their long-term cycling stability is often limited by structural degradation caused by repeated ion doping and dedoping. In this study, PPy–WS2 nanocomposites with systematically varied WS2 loadings were synthesized through an in-situ oxidative polymerization approach to elucidate how WS2 content influences morphology, surface chemistry, charge-transfer behaviour, and overall electrochemical performance. Unlike conventional reports that primarily highlight performance metrics of PPy-based hybrids, this work establishes a clear composition–structure–performance relationship and identifies the optimal WS2 fraction required to balance pseudocapacitive activity with mechanical and structural stability. Physicochemical characterization confirmed the successful integration of WS2 within the PPy matrix, forming an interconnected architecture that enhances electroactive-site accessibility and facilitates efficient ion and electron transport. Among the prepared materials, the PPy–20W electrode delivered the highest specific capacitance of 911 F g−1 at 1 mV s−1, along with excellent cycling durability. The improved performance arises from synergistic PPy redox activity, WS2-mediated interfacial charge storage, and enhanced charge-transfer kinetics. An asymmetric supercapacitor assembled using the optimized composite achieved an energy density of 32.5 Wh kg−1 and a power density of 1400 W kg−1, demonstrating the effectiveness of controlled WS2 incorporation for advancing PPy-based supercapacitor electrodes.

Słowa kluczowe:
Polypyrrole, WS2, Dichalcogenide, Supercapacitor

Streszczenie:
W niniejszej pracy przedstawiono metodykę wyznaczania charakterystyk obciążeniowych motoreduktora, którego budowa opiera się na szczotkowym mikrosilniku prądu stałego i dołączonej szeregowo trójstopniowej przekładni planetarnej. Przedstawiono opis matematyczny motoreduktora i metodykę wyznaczania parametrów: rezystancji, stałej momentu, sprawności przekładni planetarnej. Omawiane parametry poddano weryfikacji na podstawie kart katalogowych producenta mikrosilnika i przekładni planetarnej. Zaproponowana metodyka pomiarowa pozwala na wyznaczenie parametrów i charakterystyk motoreduktora nawet wtedy, gdy producent nie oferuje kart katalogowych lub zawierają one niepełne informacje.

Słowa kluczowe:
motoreduktor, charakterystyki obciążeniowe, moc wyjściowa, sprawność

Streszczenie:
W artykule przedstawiono koncepcję Układu Ekstremalnie Modularnego Shelter-Z, opartego na jednym rodzaju przestrzennego betonowego prefabrykatu ochronnego. Odpowiednie sposoby łączenia identycznych modułów umożliwiają tworzenie kopuł oraz wydłużonych sklepień kolebkowych zakończonych półkopułami, a tym samym schronów przydomowych o różnej powierzchni. Zewnętrzną warstwę prefabrykatu przewidziano jako lekki fibrobeton pochłaniający energię pocisków i odłamków oraz ograniczający ryzyko ich rykoszetowania. Zastosowanie jednego rodzaju powtarzalnego modułu upraszcza produkcję i logistykę, a przede wszystkim umożliwia automatyzację i robotyzację procesu montażu schronu.

Słowa kluczowe:
automatyzacja montażu, prefabrykat ochronny, robotyzacja budownictwa, schron przydomowy, Układ Ekstremalnie Modularny

Streszczenie:
This work derives and numerically investigates a corrected stationary formulation of the extended 2D Gao beam. Starting from the model introduced by Dyniewicz, Shillor and Bajer (Meccanica, 2024), the governing equations are rederived under a simplified loading configuration. The resulting formulation corrects inconsistencies in the previous rotational equilibrium equation and, unlike the previous formulation, reduces exactly to the classical Gao beam when the shear deformations vanish. The extended 2D Gao beam combines the nonlinear features of the classical Gao beam with an independent rotation of the cross sections, as in Timoshenko beam theory, and is therefore suitable for describing moderately thick beams undergoing buckling. The full stationary model consists of three highly nonlinear coupled differential equations supplemented by appropriate boundary conditions. Its variational formulation is derived from the potential energy functional, and the solutions are its stationary points. A reduced model consisting of two coupled equations is then constructed and investigated. Based on its variational formulation, a Finite Element Method (FEM) algorithm is developed and implemented. Five numerical examples illustrate the behavior of the corrected model and identify the loading and parameter regimes in which its predictions are similar to or different from those of the classical Gao beam. The proposed formulation may provide a useful modeling tool for moderately thick beam-like structures, including those in micro-electromechanical systems (MEMS).

Słowa kluczowe:
Extended static gao beam, 2D beam, Shear, Variational form, Simulation

Streszczenie:
The paper presents results from comprehensive experimental investigations into the activation of stockpiled granulated blast-furnace slag [GBFS] by high-intensity ultrasound [HIU, 20 kHz, 700 W] in cementitious systems. The study covered cement pastes and mortars with 20 wt.% intermediate GBFS fraction [125–250 μm] replacement. The analytical programme comprised: isothermal calorimetry, R3 reactivity test [EN 196-12:2025], Strength Activity Index [SAI per ASTM C618], ICP-OES ion dissolution analysis, and mercury intrusion porosimetry [MIP]. The BFS fraction subjected to 10 min HIU achieves, in mortar, a 2-day compressive strength equivalent to 100 % Portland cement reference [SAI = 96–102 %]. Cumulative R3 heat release increases by 132 % [189 → 439 J/g BFS]. A 40-fold increase in dissolved Ca [ICP-OES] establishes cavitation-enhanced ion leaching as the primary activation pathway. MIP reveals total mortar porosity reduction from 21.8 % to 15.1 % [–31 %], with capillary pore fraction [>1000 nm] dropping from 8.2 % to 3.4 % [–59%]. Cross-system analysis yields, for the first time, a quantitative activation transfer coefficient: 44 % at 2 days and 80 % at 28 days.

Słowa kluczowe:
high-intensity ultrasound, stockpiled blast furnace slag, early strength, cement mortar, PCE superplasticizer, SCM reactivity, R3 test

Streszczenie:
Przedstawiono przegląd wymagań funkcjonalnych i materiałowych dotyczących betonu w obiektach wyspy jądrowej elektrowni AP1000. Dokonano analizy obciążeń eksploatacyjnych i awaryjnych oraz poziomów ekspozycji na promieniowanie jonizujące. Zagrożenia dla trwałości konstrukcji zostały odniesione do temperatury i wilgotności w warunkach eksploatacyjnych oraz właściwości składników betonu. Przegląd uwypukla wyzwania związane z doborem miejscowego kruszywa i spoiwa do wykonania mieszanki betonowej oraz z projektowaniem betonu na trwałość w środowisku oddziaływań radiacyjnych.
An overview of functional and material requirements for concrete in the nuclear Island structures of the AP1000 nuclear power plant is presented. Operational and accidental loads, as well as exposure levels to ionizing radiation, were analyzed. Risks to structural durability were evaluated in relations to operating temperature and humidity conditions, as well as the properties of concrete constituents. The review highlights challenges related to the selection of local aggregate and binder for the concrete mix, and to the design of concrete for durability in a radiation environment.

Słowa kluczowe:
eton osłonowy, cement, kruszywo, promieniowanie, trwałość, radiation-shielding concrete, cement, aggregate, radiation, durability

Streszczenie:
Classical continuum theories neglect surface-dominated effects that govern the mechanical response of nanostructures at high surface-to-volume ratios (SVR). Using molecular dynamics simulations, this work examines the size-dependent free transverse vibration of solid and hollow silicon nanobeams and shows that hollow geometries exhibit a non-monotonic dependence of natural frequency on cavity size, in contrast to the monotonic surface-induced softening displayed by solid nanobeams. For small cavities, geometric stiffening from the redistribution of material away from the neutral axis outweighs surface softening, increasing the frequency despite a rising SVR; as the cavity enlarges and the walls thin, the negative surface elastic constants of silicon dominate, producing a pronounced frequency drop. This competition is shown to be quantitatively consistent with an extension of the Miller–Shenoy surface-elasticity framework to hollow cross-sections, and is distilled into a minimal two-term dimensionless scaling law that balances a geometric stiffening term against a surface-softening term governed by the ratio of an intrinsic material length scale to the beam's outer dimension. The scaling law predicts the cavity ratio at which the stiffening-to-softening transition occurs, and the molecular dynamics results show this transition at a smaller cavity ratio than the continuum prediction, pointing to an additional, cross-section-dependent atomistic contribution to surface softening not captured by the linear continuum model. These results clarify the competing mechanisms governing the vibrational response of hollow nanobeams and provide a predictive, extensible framework connecting molecular-scale surface elasticity to continuum-level nanoscale design.

Słowa kluczowe:
Hollow nanobeams, Non-monotonic vibration, Surface-to-volume ratio, Size-dependent effects, Molecular dynamics

Streszczenie:
Plasmonic materials have great potential to enable practical applications in the mid-infrared range and would gain in controllability if they were anisotropic. Here, we report an anisotropic mid-infrared plasmonic metamaterial made of less lossy ZnO:Al (AZO) layers embedded in a dielectric ZnWO4 matrix. The described material exhibits a resonance at the 3-4 μm region, which can be switched on/off by changing light polarisation. Polarisation-dependent reflectance spectroscopy, effective medium and finite-difference time-domain modelling demonstrate that the metamaterial exhibits an epsilon-near-zero (ENZ) hybrid photonic-plasmonic resonance, resembling radiative Berreman modes supported by bulk plasmon polaritons in metal thin films. Remarkably, electric field injection into such layers is realised in a simple far-field experiment without prism or focused beams. Importantly, the material is made with the eutectic solidification, which enables achieving AZO layers through self-organisation process. Additionally, the widely used crystal growth techniques could enable manufacturing metamaterials on a large scale using the eutectic solidification both in the bulk and thin film form. The methodology can be extended to multiple material combination and it opens the way to tuneable infrared metamaterials operating at different wavelengths that can find application such as resonant dichroic filters, reflectors, light-trapping structures, and sensors.

Streszczenie:
In this paper, a framework for computer-vision-based structural health monitoring (CVSHM) of truss structures under unknown load conditions is proposed. This framework is designed for highly contaminated measurement data, which are typical in CV measurements. The framework uses area-based template matching to extract nodal displacements from video, modal identification with SSI-DATA, automated rejection of out-of-plane vibration modes, automated rejection of gross errors, and model-updating-based damage assessment constrained to non-increasing stiffness with iterative rejection of structure members identified as non-damaged. The robustness to large measurement errors (up to 50 % RMS) is achieved. Excellent performance of the proposed framework is demonstrated on synthetic yet realistic videos and using available ground-truth data.

Słowa kluczowe:
Visual and Optical Testing (VT/OT), Other Methods, Computer vision, Structural Health Monitoring, Model updating, Inverse estimate, Robust damage assessment, Non-negative least square method, Physics-based graphical models

Streszczenie:
The interpenetrated composites are of high practical importance. A search for their property improvement is still ongoing. Usually, alumina-interpenetrated composites are filled with an aluminium alloy, AlSi12, which provides the composite with some ductility. However, the skeleton is brittle. In this case, the brittleness resistance of the skeleton is investigated. The interface properties Al2O3/AlSi12 were investigated in [1].
The present study investigates corundum crystals and amorphous alumina with graphene
layers. The graphene layers are stacked, displaced, and rotated. The representative volume element (RVE) for corundum consists of a few crystals with graphene layers of different orientations. The equivalent material properties of the RVE are evaluated by focusing on the properties of the phase interfaces within the RVE. In particular, imperfections due to vacancies and impurities are investigated.
The analyses are carried out using the LAMMPS environment[2]. Tersoff and Airebo
potentials are used to model graphene layers. The COMB3 (Charge-Optimized Many Body)
potential is used for alumina and corundum.
The results show an increase in the fracture toughness of the Al2O3 material used as the
skeleton in the interpenetrated composites, providing hints for the fabrication technology.

REFERENCES
[1] M. Tahani, E. Postek, T. Sadowski, Diffusion and interdiffusion study at Al- and O-terminated
Al2O3/AlSi12 interface using molecular dynamics simulations, Materials, Vol. 16, pp. 4324-1
11, 2023.
[2] A.P Thompson, H.M. Aktulga, R. Berger, D.S. Bolintineanu, et. al.. LAMMPS - a flexible
simulation tool for particle-based materials modeling at the atomic, meso, and continuum scales.
Computer Physics Communications, Vol. 271, pp. 108171-1-33, 2022

Słowa kluczowe:
alumina, graphene, molecular dynamics, elastic properties

Streszczenie:
Despite the remarkable progress in neural models, their ability to generalize—a cornerstone for applications like logical reasoning—remains a critical challenge. We delineate two fundamental aspects of this ability: compositionality, the capacity to abstract atomic logical rules underlying complex inferences, and recursiveness, the aptitude to build intricate representations through iterative application of inference rules. In the literature, these two aspects are often confounded together under the umbrella term of generalization. To sharpen this distinction, we investigated the logical generalization capabilities of pre-trained large language models (LLMs) using the syllogistic fragment as a benchmark for natural language reasoning. We extend classical Aristotelian syllogistic forms to build more complex structures, providing a foundational yet expressive subset of formal logic that supports controlled evaluation of essential reasoning abilities. Our findings reflect this non-trivial benchmark: while LLMs demonstrate reasonable proficiency in recursiveness, they struggle with compositionality. This disparity, however, is not uniform, as a more detailed analysis reveals variability in generalization performance across individual syllogistic types, ranging from near-perfect to significantly lower accuracy. To overcome these limitations and establish a reliable logical prover, we propose a hybrid architecture integrating symbolic reasoning with neural computation. This synergistic interaction enables robust and efficient inference—neural components accelerate processing, while symbolic reasoning ensures completeness. Our experiments show that high efficiency is preserved even with relatively small neural components. As part of our proposed methodology, this analysis provides a rationale and highlights the potential of hybrid models to effectively address key generalization barriers in neural reasoning systems.

Słowa kluczowe:
neuro-symbolic systems, Large language models, compositionality, recursiveness, syllogistic logic, automated theorem proving, deductive reasoning

Streszczenie:
work presents a magnetic anomaly-based localization method for UAVs operating in GNSS-denied environments using a collaborative multi-agent approach that integrates magnetic and inter-UAV distance measurements within a Particle Filter framework via Bayesian inference. The method leverages inter-UAV ranging through ad hoc communications, making it well-suited for dynamic formations and resilient to communication disruptions and UAV failures. Following an introduction to the multiagent mission problem and a formal description of the proposed Distributed Particle Filter algorithm, a case study is presented using a magnetic field map and flight logs collected experimentally with a dedicated VTOL platform equipped with a high-precision scalar magnetometer operating over the Baltic Sea. Evaluation of various collaborative scenarios demonstrates that incorporating inter-UAV ranging significantly improves localization accuracy, reducing positioning error by 71-78% across different collaboration strategies compared to the non-collaborative baseline.

Słowa kluczowe:
multi-agent system, magnetic anomaly navigation, Particle Filter, Unmanned Aerial Vehicle

Streszczenie:
The symbiotic culture of bacteria and yeast (SCOBY) driving kombucha tea fermentation produces a cellulose pellicle with remarkable promise for biomedical applications. Unlike well-studied bacterial cellulose (BC), which is produced by single-strain cultures, the underexplored kombucha-derived bacterial cellulose (KBC) can be produced from agro-industrial waste streams and at low capital cost. This review provides an overview of the great potential of KBC for biomedical applications. First, discussions on the cooperative interactions between bacterial and yeast species within the SCOBY consortium that drive the self-assembled production of cellulose at an air-liquid interface are provided. This is followed by an examination of the influence of carbon source, fermentation conditions, and post-processing on KBC yield, crystallinity, porosity, mechanical properties, and water retention. Physical and chemical modification strategies used to tune KBC behavior are then summarized, including silver (Ag) and gold (Au) functionalization, diisocyanate crosslinking, and incorporation as a nanofiller in biodegradable polymer composites. The applications section focuses on wound dressings and antimicrobial platforms, followed by tissue engineering scaffolds suitable for 3D printing and KBC’s role as a drug delivery vehicle. The main barriers to clinical translation are discussed, including limitations in reproducibility linked to undefined SCOBY composition, limited long-term in vivo studies, and the absence of a clear regulatory pathway for functionalized KBC and composites.

Słowa kluczowe:
kombucha, bacterial cellulose, SCOBY, tea fermentation, biomedical applications, sustainable biomaterials

Słowa kluczowe:
Polymer electrolytes, Energy storage, Supercapacitors, Batteries

Słowa kluczowe:
Stainless Steel, Shape Memory Alloys, Acoustic Emission, Digital Image Correlation, Infrared Thermography

Streszczenie:
Vibration remains one of the key challenges across mechanical engineering, motivating ongoing advances in damping and control. Since dissipated energy is typically lost as heat, recent research increasingly explores the integration of vibration suppression with energy harvesting [1].

This work proposes a semi‑active modal control strategy that enables precise energy transfer between selected vibration modes by locking or unlocking rotational joints, effectively switching the structural stiffness. This induces modal coupling and imposes directed energy flow. Such an approach can be employed for two functional objectives: damping, by shifting energy from low‑frequency modes to higher, more strongly damped ones, and energy harvesting, by concentrating energy in a target mode tuned to a harvester. The approach shows excellent performance in simulations and experiments [2]. Here, the focus is placed on robustness with respect to modeling errors, demonstrating that the controller remains effective despite substantial stiffness deviations. Experimental results are compared with those obtained using a finely calibrated model with 17 adjusted stiffness parameters.

Results demonstrate that, despite substantial changes in natural frequencies (up to 80 %) due to stiffness errors in the model used by the controller, the control performance is nearly the same as for the controller based on the calibrated model. Due to these advantages and the high control performance, the proposed control strategy has broad applicability to real engineering structures and is robust to changes in structural properties caused by operational wear.

[1] T. Yang, S. Zhou, G. Litak, X Jing, Recent advances in correlation and integration between vibration control, energy harvesting and monitoring. Nonlinear Dyn. 111, 20525–20562, 2023.
https://doi.org/10.1007/s11071-023-08999-2

[2] M. Ostrowski, Semi-Active Control of Energy Transfer Between Vibration Modes in Mechanical Structures, Institute of Fundamental Technological Research, Polish Academy of Sciences, 2025
https://doi.org/10.24423/9788365550644

Słowa kluczowe:
Semi-Active Modal Control, Lockable Joints, Modal Energy Transfer, Robust Vibration Control, Experimental Validation, Model Updating

Słowa kluczowe:
Additive manufacturing, Laser powder bed fusion (LPBF), Yield surface, Multiaxial loading

Słowa kluczowe:
Inconel, Yield Surface, Additive Manufacturing, Laser Engineered Net Shaping

Słowa kluczowe:
Yield Surface, Szczepiński Yield Function, Kinematic Hardening, Multiaxial Probing

Słowa kluczowe:
Fatigue, Damage, Optical methods, Indicators of damage Development

Słowa kluczowe:
Crack propagation, Radiation defects, MD simulations, Cr-rich alloy, T–S law, Atomic-scale fracture energy, ductile-to-brittle transition

Streszczenie:
Many data types, such as video and audio, consist of sequential elements where both integrity and order are essential for authenticity. In practice, verifiers often access only partial sequences due to privacy or bandwidth constraints, motivating the use of vector commitments (VCs) for verifiable partial disclosure. However, VC construction requires a trusted committer, typically within a secure module on the device, and maintaining such commitments is challenging for resource-constrained hardware. For example, in CCTV pipelines, a trusted module processing continuous streams must store and update large VC structures, leading to prohibitive memory and computational overhead.
This work addresses this deployment bottleneck by introducing an efficient pipeline for verifiable VC construction that offloads computation from constrained devices while preserving trust. The source device computes and signs a cumulative hash over the data stream, requiring only constant memory. Later, an untrusted prover reconstructs the VC from the raw data and produces a zero-knowledge proof that the construction is consistent with the signed hash chain. This design eliminates the need for trusted storage of intermediate VC state and enables verifiable partial disclosures from the reconstructed VC.
A key challenge is the high cost of proving the full VC construction. We address this by designing a folding-based zkSNARKs system tailored to streaming workloads. We implement and evaluate the system on a constrained device (Raspberry Pi Zero) as the source and a consumer-grade prover (midrange laptop). Our results show that direct VC maintenance on the source device requires hundreds of megabytes of memory and is computationally infeasible on trusted platform standards for even moderate workloads (e.g., 30 minutes of video). In contrast, our approach reduces the
trusted device’s memory footprint to constant size, while the midrange laptop can generate the proof of full VC construction in approximately 2 minutes for the same workload. Furthermore, the proof size is around 10 KB regardless of the original size of data and verification time is sub-second. Our implementation is available open source at: https://github.com/zero-savvy/proven-view.

Słowa kluczowe:
zkSNARKs, Provenance, Vector Commitments, Folding Schemes

Streszczenie:
A method presented here links: (i) the analytic formulas for lattice distortions derived from the linear theory of dislocations, (ii) a tensor algebra of distortion fields, and (iii) the atom-by-atom reconstruction of a network of dislocation cores into crystal lattice.

Configurations of atoms obtained in this way satisfy the stress equilibrium condition in terms of the linear theory of elasticity.
On the other hand, the spatial Burgers vectors of dislocations are stretched and rotated to each other according to the finite deformation theory. Such obtained the resultant network of dislocations can be used next as the input data for the ab-initio and/or molecular dynamics programs to find a low energy configuration of atoms corresponding to a given interatomic potential.

Słowa kluczowe:
dislocations, distortion fields, dislocation networks

Słowa kluczowe:
Bio-derived materials, Sustainable sources, Porous Carbon, Electrochemical Energy Storage, Supercapacitors

Słowa kluczowe:
crystal growth, hyperelasticity, residual stress fields, optimization of chemical composition

Słowa kluczowe:
nonlocal elasticity theory, nanorods, post-buckling behavior

Słowa kluczowe:
LIDAR ODOMETRY, IMU, LIO, SLAM

Streszczenie:
Multimodal deep neural networks enhance deep comprehension by integrating diverse data modalities. Data from different modalities are typically projected into a shared latent space for similarity computation, but this process is resource intensive due to large image encoders and equal processing of test data during prediction. Early exit methods reduce computational load by utilizing intermediate layers, saving time and memory. However, developing such methods is challenging for multimodal data like image-text pairs. This study investigates the semantic content distributions present in intermediate layers of encoders such as CLIP, which can be derived from textual descriptions. We introduce Text-Guided Exit Modules (T-GEMs) and a rate-based regularizer to control encoder usage costs while maintaining cross-modal understanding performance.

Słowa kluczowe:
early exit method, multimodal model, distribution parameter estimation

Streszczenie:
This contribution presents, verifies and illustrates a method for time-domain constrained mode decomposition via autoregressive modeling (TCMD-AR). TCMD-AR is a recently proposed data-driven signal decomposition method aimed at reliable identification of complex eigenvalues (modal frequencies and damping ratios) and extraction of pure single-mode free decay signals from recorded structural free responses. The core idea of the TCMD-AR method is to form single-mode signals as linear combinations of the measured structural free responses. The combination coefficients are determined by enforcing a time-domain characteristic constraint equation. This equation is derived based on specific characteristics of the autoregressive (AR) model of a single-mode signal, and it yields a constraint matrix whose null space encodes the free decay signal of the targeted mode. In contrast to many existing data-driven decomposition methods, which often suffer from modal aliasing and limited physical interpretability, the approach of TCMD-AR ensures that the resulting decomposed single-mode signals show negligible modal aliasing (see an example in the attached figure) and have a transparent physical interpretation. In fact, as linear combinations of structural responses, they are guaranteed to satisfy the structural equation of motion. In TCMD-AR, the process of modal identification and signal decomposition proceeds iteratively by estimating candidate complex eigenvalues using the Yule--Walker equations, eliminating spurious eigenvalues, and decomposing the signal based on the determined true eigenvalues. The basic decomposition tool is a single- or multi-eigenvalue constraint FIR filter, based on the autoregressive model and Prony polynomial, which is designed to target and/or suppress specific eigenvalues in the input response. The effectiveness of TCMD-AR is confirmed in numerical and experimental tests. Numerical experiments on simulated structures are used to quantify robustness to noise and stability of the results, and for comparison with typical approaches such as VMD and CEEMDAN. Experimental tests, conducted in laboratory conditions using a shear frame structure, confirm the accuracy of identification results (modal frequencies and damping rations) by comparing them with the results obtained from the eigensystem realization algorithm (ERA) and signal processing through power-exponential window techniques.

Słowa kluczowe:
modal identification, mode decomposition, autoregressive model, constraint filter, Prony polynomial

Streszczenie:
Load identification is a crucial topic in structural health monitoring (SHM). Existing approaches involve a trade-off between the amount of data required and the fidelity of available parametric physical models. Purely data-driven methods require extensive labeled training data for reliable identification and lack physical interpretability. Methods based on physical model inversion techniques are interpretable, but their accuracy depends on precise knowledge of the structural model and its parameters, which requires extensive model-tuning procedures. This contribution presents and discusses a physics-augmented deep learning (PADL) framework, intended for identification of structural dynamic excitations and aimed at striking the balance between data and model precision demands. A long short-term memory (LSTM) neural network is used as the basic identification tool. However, in contrast to typical data-driven methods, its input consists of not only measured structural responses. It includes also the results of FRF-based inverse processing performed with a simplified, reduced-order model of the monitored structure, yielding inexact estimates of the unknown input and state vector. In this way, the typical data-based input is augmented with a physically consistent data that indirectly embeds and provides information about the physical structure and its equations of motion. Such a dual-input design effectively addresses the trade-off noted above: on the one hand, the required structural model can be very coarse, inexact and reduced-order, on the other, the physical consistency of the information it provides (even if it is strongly simplified and approximate) significantly reduces the amount of training data required. Moreover, the employed FRF-based approximate model inversion is sensor-agnostic, which enables applications with heterogeneous sensor networks. A specific data normalization scheme ensures applicability across a range of excitation amplitudes. The proposed PADL framework is verified in numerical simulations and laboratory experiments using random and impulsive excitation profiles. The tests demonstrate that PADL outperforms purely physics-based and purely data-driven baseline methods and that high identification accuracy can be achieved even with very small training sets and highly simplified structural models and inaccurate parameters. An ablation study confirms that including the approximate state vector in the input data, in addition to the computed approximate excitation, provides additional physically consistent information and is important for the accuracy of the obtained identification results.

Słowa kluczowe:
machine learning, load identification, physics-informed, small training samples

Streszczenie:
This contribution presents a semi-active structural control strategy built on reinforcement learning (RL). Even though RL has recently achieved superhuman performance in a range of challenging, control-oriented real-world tasks, its use in structural control remains limited. A seismically excited shear-type structure is considered and fitted with a tuned mass damper (TMD). This TMD, after optimal tuning, is used as a baseline for comparison. The proposed RL control system switches the damping coefficient of the TMD dashpot between two discrete levels corresponding to a negligible damping and a high damping state. The switching policy is encoded in the form of an artificial neural network that is trained through a simulated trial-and-error process. Sensor measurements serve as inputs to the network. The control signal is the outputs from the network. The training process seeks to maximize control performance in terms of interstory drift and total mechanical energy reduction. Abrupt activation of viscous damping can result in inelastic impacts, an additional acceleration-based penalty term is used to limit such effects. Results show that the RL-based controller outperforms the optimally tuned passive baseline and has reasonable tolerance to measurement errors. The degree of this robustness depends on the number of sensors.
The authors gratefully acknowledge the support of the National Science Centre, Poland, granted under the grant agreement 2020/39/B/ST8/02615. For the purpose of Open Access, the authors have applied a CC-BY public copyright licence to any Author Accepted Manuscript (AAM) version arising from this submission.

Słowa kluczowe:
semi-active control, structural control, reinforcement learning, bang-bang control

Streszczenie:
Reinforcement learning (RL) is a class of machine learning methods aimed at solving control-like tasks. Control is learned and applied by an agent that learns to select the best action through a series of interactions with the controlled system.

A potential application area of reinforcement learning is semi-active structural control. In such tasks, the optimal control signals are often unknown and cannot thus be used for training, as required by typical supervised learning techniques. The RL approach is more suitable, as it allows the control agent to progressively improve its decision-making strategy in a trial-and-error manner based on experiencing and received feedback (reward). This interaction-based approach also goes beyond typical unsupervised techniques, as it allows control signals to be actively tested rather than merely exploring pre-prepared datasets. Despite these advantages and remarkable achievements in other fields, reinforcement learning methods are still rarely applied in structural control, especially in semi-active control.

This contribution continues our earlier work on RL-based control of a seismically excited shear-type building, which examined the robustness of a typical single-agent RL controller. Here, the investigation is extended to multi-agent RL control, in which the ultimately applied control action is determined based on the recommendations of a group of independent RL agents. Control is applied via a tuned mass damper whose mass can be locked to or unlocked from the story in an on/off manner. The reward function used for agent training quantifies structural vibrations, and additionally, it includes a penalty term that promotes locking at moments of zero relative velocity, in order to avoid the associated impacts.

Słowa kluczowe:
Tuned Mass Damper, Semi-active Control, Reinforcement Learning, Multi-agent Control, Robustness

Streszczenie:
Despite decades of research on semi-active vibration control of mechanical structures, the development of an effective control system for frame structures with multiple lockable joints remains a significant challenge. The primary difficulty arises from the nonlinear operational characteristics of such systems: switching the joint states alters the structural configuration and, consequently, its natural frequency spectrum. In addition, the complex frictional and sliding behavior of lockable joints makes accurate modeling of the system dynamics inherently approximate.

In this study, we propose a reinforcement learning (RL)-based semi-active vibration control strategy. Control decisions are determined using a Deep Q-Network (DQN), one of the fundamental algorithms in reinforcement learning. The method is applied to an eight-bay cantilever frame structure equipped with two pairs of lockable joints, operating without prior knowledge of the system dynamics. The joints allow the relative rotational motion between vertical and horizontal beams to be locked or released.

The structure is discretized using a finite element (FE) model with one beam element per bay side, resulting in a total of 24 beam-type finite elements. The RL controller learns through direct interaction with the system by estimating the effect of joint locking on the structural response. The resulting control signals are compared with an instantaneous optimal control strategy, which greedily reduces vibration energy by transferring it from low-frequency to high-frequency modes. The close agreement between the reinforcement learning-based control and the analytical optimal solution demonstrates the capability of RL algorithms to achieve effective vibration mitigation in complex, nonlinear structural systems.

Słowa kluczowe:
Reinforcement learning, Machine learning, Semi-active control, Vibration attenuation

Streszczenie:
This contribution discusses an approach for semi-active control of structures based on the machine learning technique of reinforcement learning (RL). The RL family of techniques was recently demonstrated to lead to a super-human performance in many demanding control-like real-world problems, but the applications in the field of structural control are still sparse. Here, a seismically excited shear-type structure is considered and equipped with a tuned mass damper (TMD), where the optimally tuned passive TMD serves as the baseline reference case. Its effectiveness is compared to the considered control system, which, instead of keeping the TMD’s dashpot damping constant, switches it between two values that represent a low- and high-damping state. The control function is modeled using an artificial neural network and learned in a simulated series of trial-and-error experiments. The input to the network are the sensor readings, the output is the control signal, and the learning aims to maximize the control effectiveness defined in typical terms of total mechanical energy and interstory displacement. Since switching on the viscous damping may lead to undesirable impact-like excitations, an additional penalty term is introduced to mitigate the impact effects based on acceleration readings. The investigated RL-derived control is demonstrated to surpass the baseline and be relatively robust to measurement errors, but this robustness depends on the sensor redundancy.

The authors gratefully acknowledge the support of the National Science Centre, Poland, granted under the grant agreement 2020/39/B/ST8/02615. For the purpose of Open Access, the authors have applied a CC-BY public copyright licence to any Author Accepted Manuscript (AAM) version arising from this submission.

Streszczenie:
A reinforcement learning (RL)–based strategy for semi‑active vibration control of an eight‑bay cantilever frame with four lockable joints is investigated. A Deep Q‑Network (DQN) learns joint locking policies from local strain and velocity measurements, enabling energy transfer from low‑frequency modes to higher, strongly damped ones. The required number of the joint locks and unlocks is also accounted for. The controller achieves the performance comparable to, and in some cases exceeding, a greedy modal energy‑flow algorithm, treated as a benchmark. These results highlight the potential of RL for efficient, data‑driven control of structural systems.

Słowa kluczowe:
Energy dissipation, Optimal control, Reinforcement learning, Machine learning, Lockable semi-active joints