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Textile fibers are an essential component of daily necessities and are often used as forensic evidence, making their characterization crucial in forensic science. Different types of textile fibers can be identified using their unique Raman spectral characteristic peaks. In this study, we achieved the visualization of single-component, multi-component, and dyed blended fibers through Raman spectral imaging, demonstrating the spatial distribution of different types of textile fibers within the same area. Furthermore, by merging Raman images of fibers from non-confocal planes, we achieved accurate visual identification, providing more possibilities for characterizing fibers with special morphological features using Raman spectral imaging. In conclusion, Raman spectral imaging enables the successful visualization and identification of different types of fibers. Full article

In order to study the diffusion and sealing mechanism of an innovative grouted material tentatively called “expandable particulate grout material”, the diffusion process was simulated by the numerical method of CFD-DEM coupling. A numerical model was established for a grouting process in an individual fracture based on the basic physical parameters of expandable particles. The numerical model of the expandable particulate slurry flow was established. The interaction between particles and water in different conditions, such as different grouting times, different volume fractions of the particle, and different velocities, was investigated. The differences in the diffusion process and in the running-water sealing mechanism of expandable particles, cement slurry, and cement-sodium silicate slurry in the crack (in a, in b, and in c) were analyzed. The influence of expandable particles on the streamline of the grout and the drag force in the interaction process under the fracture were analyzed. This is summarized The influence of the velocity ratio of grout to water on different physical quantities, such as diffusion opening degree, diffusion velocity, and diffusion distance, was summarized. It is of significant theoretical and practical value to further develop and improve the grouting technology. Full article

Chloroderivatives of phenoxyacetic acid are a group of compounds commonly used as plant protection products. Differences in the molecular structure of these compounds are related to varying substitution and the number of chlorine atoms in the aromatic ring. Different molecular structures may affect the activity of these compounds, their physicochemical properties, as well as their toxicity and biological effects. A group of 6 chemical compounds derived from phenoxyacetic acid was tested. The molecular structure was analysed using spectroscopic methods (FTIR, FTRaman, UV-VIS, ¹HNMR, ¹³CNMR) and quantum chemical computational methods (DFT). The reactivity of the tested compounds was determined using DFT calculations and experimentally in reaction with a hydroxyl radical. The electronic charge distribution of NBO, CHelpG and ESP was analysed and aromaticity indices were calculated for theoretically modeled structures and structures examined by X-ray diffraction (data obtained from the CSD database). Phenoxyacetic acid derivatives were tested for antimicrobial activity on soil bacterial strains. Cytotoxicity tests were performed on normal human skin fibroblasts (BJ CRL-2522) and the human prostate cancer cell line (DU-145 HTB-81). The purpose of this study was to investigate the relationship between the molecular structure of phenoxyacetic acid derivatives and their reactivity and biological activity. Full article

Fused Deposition Modeling (FDM) has emerged as one of the most widely adopted additive manufacturing (AM) technologies due to its broad material availability and low production costs, enabling the efficient production of complex geometries and customized components. Among the materials commonly used in AM, Acrylonitrile Butadiene Styrene (ABS) is particularly notable for its favorable mechanical properties, ease of processing, and versatility. While moderate-to-high-density lattice configurations have been extensively studied, low relative density lattice structures remain largely unexplored. This study investigates the feasibility of fabricating Cuboidal Body-Centered Cubic (BCC) lattice structures with relative densities of 5%, 10%, and 15% using FDM. The geometrical/dimensional accuracy of the printed samples is thoroughly assessed to quantify fabrication-induced deviations, focusing on strut geometry and overall lattice consistency. Results show that while smaller lattice configurations, particularly those with 5% relative density, exhibit significant geometrical inaccuracies due to printing limitations (e.g., strut waviness, material deposition inconsistencies, layer misalignment), larger configurations demonstrate improved dimensional and geometrical fidelity and structural integrity. A framework is proposed for assessing geometrical/dimensional fidelity, which can enhance the predictive modeling of these structures and optimize manufacturing processes. These findings clarify low relative density lattice manufacturability, guiding research on mechanical performance for lightweight aerospace applications. Full article

An assembly of fourth-century BCE Samarian silver coins and late-fifth-century BCE Samarian cut silver sheets, Sidonian and Philistian coins from a hacksilber hoard allegedly found in the region of Samaria belonging to the David and Jemima Jeselsohn collection, were characterized by metallurgical analyses. The aims of the research were to identify the items’ composition and manufacturing processes. We affirmed that the Samarian coins were made of silver–copper alloy produced by a controlled process. The microstructural and elemental analyses revealed that the sheets were produced from various materials, including pure silver, silver–copper, and silver–copper–gold alloys, whereas the Sidonian and Philistian coins were made of silver–copper alloy. Continuity in style and production techniques was observed. This information provides a better understanding of the material culture and technological skills in the Persian-period province of Samaria. Full article

Steel frame infilled with composite plate shear wall (SF-CPSW) is an effective structure for lateral-load resisting. In the structural design, the vertical loads are primarily carried by the boundary SF, while the horizontal loads are expected to be totally carried by CPSW. CPSW incorporates the steel web and the concrete encasements. For the CPSW bays, the boundary SF also inevitably withstands the lateral-loads due to the coordinated deformations between boundary SF and CPSW. The available researches, however, have not given a certain shear force assignment between the boundary SF and CPSW. Furthermore, their interactions under the cyclic lateral-loading are unclear. This paper conducted a study on the load-resisting mechanism of SF-CPSW by a structural model test and finite element analyses. The deformation pattern, failure mode, internal forces, and interactions of structural members were investigated. The effects of steel web and concrete thicknesses, cross-sections of boundary SF, and axial compression ratio on the lateral-load resistance of SF-CPSW were assessed. The results indicated that the interactions of CPSW and boundary SF caused significant normal stresses at the corners of CPSW, reducing the shear strength of steel web. However, the concrete encasements and boundary SF compensate it and mutually improved the stiffness and ductility. According to the analysis results, the formulas of the lateral stiffness and strengths of SF-CPSW were proposed for its seismic design. Full article

This study presents a Multi-layer Quasi-Zero-Stiffness (ML-QZS) vibration isolation platform for variable loads in large-amplitude and low-frequency dynamic environments. In one isolation mount of the proposed ML-QZS isolation platform, Multi-layer permanent magnets are constructed to generate discontinuous Multi-layer negative-stiffness regions. The first design criterion is to achieve the low-frequency and wide-amplitude vibration isolation range for different loads. The second design criterion is carried out for the dynamic performances of transient and steady states. Since both structural design and damping determine vibration transient time and the displacement transmissibility, which often exhibit contradictions depending on system parameters, a bi-objective Pareto optimization criterion is proposed to balance the vibration transients between different layers while ensuring significant isolation effectiveness in one layer. Finally, the relevant experimental prototype is constructed, and the results verify the design principle of Multi-layer double magnetic ring construction and optimization criterions for structural parameters and damping coefficients. This study provides an advanced nonlinear isolation platform with a wide QZS range for different loads, and the optimization method to coordinate the vibration performances, which provides important theoretical and experimental guidance for the design and realization of isolation platforms in practical engineering applications for large-amplitude and low-frequency dynamic environments. Full article

This study investigates the correlation between the cross-linked network structure and the macroscopic mechanical properties of 3,3-bis(azidomethyl)oxetane-tetrahydrofuran copolymer (PBT)-based solid propellants through molecular dynamics (MD) simulations. A multi-component system comprising PBT molecular chains, toluene diisocyanate (TDI), trimethylolpropane (TMP), tetraethylene glycol (TEG), and sodium perchlorate (AP) was constructed. Perl script programming was utilized to precisely control the dynamic cross-linking reaction. Molecular models with cross-linking densities of 0%, 50%, 60%, 70%, 80%, and 90% were established, and their mechanical properties were analyzed under varying cross-link densities and strain rates through uniaxial tensile simulations. The results indicate that the formation of the cross-linked network significantly alters the energy distribution and microstructural characteristics of the system. As the cross-linking density increases from 50% to 90%, the total energy of the system decreases by approximately 40%, primarily due to reductions in non-bonded energy. The radial distribution function (RDF) and root mean square displacement (MSD) curves reveal that the cross-linking reaction enhances covalent bond formation between molecular chains, reduces their degrees of freedom, and increases the glass transition temperature (Tg). Under identical strain conditions, the models with higher cross-link densities exhibit greater stress resistance. Specifically, the stress growth rate of the 90% cross-link density system increases by 42.1% as the stretching rate rises from 1.0 × 10¹¹ s⁻¹ to 2.0 × 10¹¹ s⁻¹, compared to an 18.7% increase for the 50% cross-link density system. These findings have significant implications for optimizing processing parameters and predicting the mechanical properties of propellants. Full article

Fibrous materials, prevalent in biological tissues and engineered composites, undergo remodeling in response to mechanical loads, leading to plastic changes in fiber orientation. A previously developed continuum model describes this remodeling process. Building on that framework, the present study examines the extreme behaviors of such materials. Analytical results for the homogeneous response under tensile loading reveal three distinct classes: in class $\left(A\right)$, fibers asymptotically approach a specific angle; in class $\left(B\right)$, fibers align perpendicularly to the load direction; and in class $\left(C\right)$, fibers align either with the load direction or perpendicularly, depending on their initial orientation. Numerical simulations are employed to analyze the non-homogeneous material response in a standard tensile test, demonstrating how differences in behavior arise from the material class and the initial fiber orientation distribution. This investigation focuses on the extreme behaviors of material classes $\left(A\right)$ and $\left(C\right)$, emphasizing phase segregation and transitions between auxetic and non-auxetic behavior. Full article

In order to achieve high-quality repair of complex curved parts, a remanufacturing process method utilizing laser cladding and reverse engineering technology is proposed to be implemented by robots. This study focuses on the oscillating helical surface of a screw pump rotor. A single-pass laser cladding test is conducted using Response Surface Methodology (RSM) to construct a predictive model and identify optimal process parameters. The model’s accuracy is validated through analysis of variance (ANOVA) and index verification, while the optimal lap rate is determined through multi-pass laser cladding testing. Using reverse engineering technology, the generation of laser cladding paths for complex surfaces is explored, and the trajectory planning for the laser cladding robot is carried out. Simulations and experiments of robotic laser cladding on complex surfaces are performed, with the optimal process parameters guiding both the experiment and simulation. The optimum single-pass cladding layer, with a lap rate of 25.6%, is achieved when the laser power is 2217 W, the powder feed rate is 2.86 r/min, and the scanning speed is 400 mm/min. The study successfully plans the path for laser cladding on complex curved parts, verifying its feasibility and effectiveness, verifying that there is good metallurgical bonding between the cladding layer and the substrate, and helping to select the appropriate process parameters that are consistent with the requirements of a particular application, thus providing valuable guidance for the remanufacture of failed metal parts. Full article

This article presents the influence of lubricant on selected tribological properties of the rolling–sliding association, i.e., the wheel–rail system. Three solid lubricants were tested: soybean grease, molybdenum disulfide and graphite grease. Under specific operating conditions, a beneficial influence of lubrication of the above-mentioned friction node was observed. This is valuable information for rolling stock owners, track operation or maintenance workers when making decisions about lubrication or its absence on a given section of railway track. In this way, tangible financial benefits (savings) are obtained by extending the durability of the wheel rim and rail, and, through extended periods of wheel set reprofiling, we significantly reduce operating costs. Solid lubricants (lubricating sticks) intended for the lubrication of railway wheel flanges must meet the requirements specified in the PN-EN 15427-2-1:2022 standard. Annex H. The wear patterns were observed and analyzed using both optical microscopy and scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDS). The test results indicate that graphite is characterized by the lowest and most stable coefficient of friction over time, which makes it the most effective lubricant in terms of friction reduction. Soybean grease also shows stability and a low level of friction, but with a slight increase in value over a longer period of time. However, grease containing molybdenum disulfide, despite its initial effectiveness, loses its lubricating properties over time, resulting in a significant increase in friction. Full article

AlCrN and AlCrSiN coatings were deposited via reactive magnetron sputtering. This study investigates the effects of radio frequency (RF) substrate bias, ranging from 0 V to 200 V, on the chemical composition, microstructure, and mechanical properties of the coatings. All crystalline coatings exhibited a single wurtzite-type hexagonal close-packed (hcp) structure. At a 0 V substrate bias, the AlCrN coating consisted of porous V-shaped columnar crystallites, while the AlCrSiN coating exhibited a porous, fiber-like amorphous structure. As the substrate bias increased, crystal growth was promoted, void density decreased, and the surface morphology transitioned from a textured to a more rounded appearance. Additionally, the preferred orientation shifted toward the (101) direction. However, at excessively high substrate bias, re-nucleation occurred, leading to grain refinement and increased film densification, which in turn caused a further shift in the preferred orientation toward the (002) plane. Due to its multi-element composition and the low solubility of Si in nitrides, AlCrSiN coatings tend to exhibit an amorphous growth tendency during sputtering. As a result, their microstructure is more sensitive to substrate bias. This sensitivity results in the formation of a highly dense structure with an optimal crystallite size at a substrate bias of 100 V, leading to a hardness of 22.6 GPa—surpassing that of the AlCrN coating. Full article

This study investigates the effectiveness of trochoidal (adaptive) milling in machining Glass Fiber Reinforced Polymer (GFRP), emphasizing its potential advantages over conventional milling. Six coated solid carbide end mills, each with distinct geometries, were evaluated under identical conditions to assess the cutting forces, surface quality, dimensional accuracy, burr formation, chip size distribution, and tool wear. Trochoidal milling demonstrated shorter cycle times—up to 23% faster—and higher material removal rates (MRRs), while conventional milling provided superior dimensional control and smoother surfaces in certain fiber-sensitive regions. A four-tooth cutter with a low helix angle (10°) and aluminum-oxide coating delivered the best overall performance, balancing minimal tool wear with high-quality finishes (arithmetic mean roughness, Ra, as low as 1.36 μm). The results indicate that although conventional milling can exhibit a 25%-lower RMS cutting force, its peak forces and extended machining times may limit the throughput. Conversely, trochoidal milling, when coupled with an appropriately robust tool, effectively manages the cutting forces, improves the surface quality, and reduces the machining time. Most chips produced were less than 11 μm in size, highlighting the need for suitable dust extraction. Notably, a hybrid approach—trochoidal roughing followed by conventional finishing—offers a promising method for achieving both efficient material removal and enhanced dimensional accuracy in GFRP components. Full article

The drilling of ultradeep oil wells brings many challenges to the downhole tubular materials, where corrosion induced by halide annulus protection fluid is one major problem. In this work, the Na₂CO₃/NaHCO₃ buffer system is employed to mitigate the corrosion of C110 steel in NaBr annulus protection fluid at 220 °C. Weight loss tests, corrosion morphologies characterizations, and electrochemical measurements were used to investigate the inhibition effect. X-ray diffraction and X-ray photo-electron spectroscopy were employed to analyze the surface phase compositions. It is found that the Na₂CO₃/NaHCO₃ buffer reagents effectively inhibit the corrosion of C110 steel, and the inhibition efficiency can reach 96.1%. The higher pH leads to the better inhibition performance, and, particularly, the buffer system is more effective in the corrosion environment of greater aggressivity. Without buffer reagents, the steel substrate is subjected to higher degree of uniform etching and pitting corrosion due to the formation of loose and porous corrosion products. In contrast, the addition of buffer reagents facilitates the formation of thinner but denser and more protective Fe₃O₄ passive film, contributing the high corrosion inhibition efficiency. Our work paves the way for the safe service of NaBr annulus protection fluid at 220 °C in ultradeep oil wells. Full article