Search Results (1,523)

Desertsand concrete (DSC) is a sustainable alternative to natural river sand; however, its application in cold regions is restricted by inadequate crack resistance and freeze–thaw durability. This study investigates the freeze–thaw performance of steel–polypropylene hybrid fiber-reinforced desert sand concrete (SPHF-DSC), with emphasis on durability enhancement and service life prediction. A three-factor, three-level orthogonal experimental design was employed to evaluate the effects of desert sand replacement ratio (DSR), steel fiber (SF) content, and polypropylene fiber (PPF) content on mass loss, relative dynamic elastic modulus, and compressive strength under 25–100 freeze–thaw cycles. The results demonstrate that hybrid fiber reinforcement significantly improves freeze–thaw resistance due to the synergistic interaction between SF and PPF. After 100 cycles, the mass loss of all specimens remained within a narrow range of 0.65% to 0.73%, and the relative dynamic elastic modulus retention stayed above 90%. The optimal mixture (DSR = 30%, SF = 2%, PPF = 0.05%) exhibited superior frost resistance with the lowest deterioration indices among all groups. A freeze–thaw damage model based on damage mechanics was established and validated ($R^2$ > 0.96), enabling prediction of a service life exceeding 38 years under typical cold-region climatic conditions. These findings provide a durability-oriented design reference for the engineering application of DSC in cold-region infrastructure. Furthermore, the utilization of local desert sand reduces transportation energy consumption and promotes the sustainable development of energy infrastructure. Full article

The growing need for lightweight, multifunctional, and high-performance structures in the automotive, aerospace, electronics, and medical industries has driven the development of advanced joining technologies for polymers and metal-polymer combinations. Among these, ultrasonic welding (USW) and friction stir spot welding (FSSW) have emerged as promising solid-state techniques capable of producing reliable joints with minimal thermal degradation and enhanced interfacial bonding. This review focuses on recent developments in USW and FSSW of thermoplastics, fiber-reinforced composites, and hybrid metal–polymer systems, with a particular emphasis on process mechanics, microstructural evolution, and joint performance. The mechanisms of heat generation, material flow behavior, and consolidation are discussed in relation to key process parameters, including applied pressure, rotational speed, vibration amplitude, plunge depth, and dwell time. Microstructural transformations such as polymer chain orientation, recrystallization, interfacial diffusion, and defect formation are analyzed to establish process–structure–property relationships. Mechanical performance metrics, including lap shear strength, fatigue resistance, impact behavior, and environmental durability, are critically compared across different materials and welding methods. Furthermore, recent advances in numerical and thermo-mechanical modeling, in situ process monitoring, and data-driven optimization are discussed to highlight pathways toward predictive and scalable manufacturing. Current industrial applications and existing limitations such as challenges in automation, thickness constraints, and hybrid material compatibility are also evaluated. Finally, key research gaps and future directions are identified to improve joint reliability, sustainability, and broader industrial adoption of advanced solid-state welding technologies. Full article

The central role of YB-1 in messenger ribonucleoprotein particle (mRNP) metabolism and stress-granule biology highlights the importance of defining the determinants of its self-assembly. YB-1 fibrillogenesis has been attributed primarily to the cold shock domain (CSD). Here, we show that the YB-1 fragment spanning residues 1–129 (AP–CSD) form amyloid fibrils under near-physiological ionic strength (0.12–0.15 M KCl). Fibrillization proceeds without a pronounced exponential growth phase and increases approximately linearly over 45–50 h. Far-UV circular dichroism (CD) and attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) indicate no substantial change in overall secondary-structure content during aggregation. In parallel, ¹H nuclear magnetic resonance (NMR) spectroscopy reveals the depletion of soluble species, and oriented fiber X-ray diffraction displays the hallmark cross-β reflections at approximately 4.7 Å and 10 Å. The prolonged formation time implies an activation barrier that is unlikely to require global refolding. Instead, it may reflect early association events such as dimerization or other local rearrangements required for primary nucleation, followed by consolidation into stable intermolecular contacts. Aggregation that preserves a largely native-like fold while establishing cross-β order may reduce recognition by cellular quality-control systems that preferentially target globally unfolded or strongly destabilized states. This provides a plausible framework for how YB-1 derived assemblies could persist under stress and during age-associated proteostasis decline. Full article

To address the issues of high cutting temperatures and severe tool wear during titanium alloy machining, this study proposes a hybrid surface modification strategy combining micro-textures and multicomponent titanium nitride (TiN)-based coatings on cemented carbide tools. Using YG8 cemented carbide as the substrate, micro-dimple textures were fabricated by fiber laser, and three coatings with different architectures (TiAlSiN, TiSiN/TiAlN, and TiSiN/TiAlSiN/TiAlN) were deposited via multi-arc ion plating technology. Based on a two-factor (texture diameter and texture spacing) and three-level orthogonal experiment, the evolution behaviors of surface morphology, phase composition, and mechanical properties of the textured multicomponent TiN-based coatings were systematically characterized and comparatively analyzed. The results reveal that: compared to the monolithic-structured TiAlSiN coating, the TiSiN/TiAlSiN/TiAlN and TiSiN/TiAlN composite coatings with multilayered composite structures can effectively relieve the residual stress inside the film–substrate system, and significantly suppress the phenomena of coating cracking and localized spallation caused by irregular protrusions of the recast layer at the micro-texture edges. X-ray diffraction (XRD) and crystallite size analyses indicate that the amorphous Si₃N₄ phase promoted by the Si element in the composite coatings effectively impedes the growth of TiN columnar crystals, achieving significant grain refinement. Mechanical property tests confirm that the existence of multicomponent composite interfaces effectively hinders dislocation movement. Among them, the textured TiSiN/TiAlSiN/TiAlN composite coating exhibits the optimal comprehensive performance; its microhardness, nanohardness, and H/E ratio (characterizing the resistance to plastic deformation) are increased by 17.94%, 8%, and approximately 45%, respectively, compared to those of the textured TiAlSiN coating. This study deeply elucidates the synergistic strengthening and toughening mechanisms between micro-texture parameters and the internal structures of the coatings, providing important theoretical guidance and experimental data support for the surface design of long-lifespan tools oriented towards the high-efficiency machining of titanium alloys. Full article

Fatigue cracking and stiffness degradation remain critical challenges for concrete flexural members used in bridge decks, crane beams, pavements, and other structures subjected to repeated loading. Layered beams that combine normal concrete in the compression zone with steel-fiber concrete in the tension zone offer a promising route to reduce self-weight while retaining crack resistance and ductility. However, the coupled influence of layer depth and fiber dosage on the flexural fatigue response of such members is still insufficiently quantified for reliable engineering design. Unlike previous studies that mainly focused on homogeneous SFRC members, UHPC-based members, or layered beams under static loading, the present study addresses a more practice-oriented but less explored problem, namely the flexural-fatigue behavior of cast-in-place layered beams composed of normal concrete in compression and steel-fiber concrete in tension. More importantly, the study does not examine fiber effect or layer geometry separately, but quantifies within one unified framework how lower-layer height ratio and fiber dosage jointly govern fatigue life, stiffness retention, crack development, and failure transition. A calibrated nonlinear finite-element model with damage-plasticity constitutive laws and cycle-block degradation was further established to reproduce the experiments and to conduct a broader parametric study. The results show that no horizontal crack formed at the cast interface and that the strain-deflection response preserved the typical three-stage fatigue evolution. Increasing either the steel-fiber volume fraction from 0.8% to 1.6% or the lower-layer height ratio from 0.5 to 0.7 markedly prolonged fatigue life and improved crack control. A practical fatigue-life relation, a stiffness-degradation law, and a numerical response surface are proposed, indicating that a height ratio of 0.6–0.7 combined with a fiber dosage of 1.2%–1.6% provides the best balance between fatigue durability, stiffness retention, and failure ductility. Full article

This study addresses the limited availability of unified experimental datasets comparing ribbed steel and smooth FRP bars embedded in the same hybrid-fiber high-performance concrete (HPC) matrix under identical conditions. It investigates the mechanical and bond behavior of a triple-fiber HPC combining hooked-end steel (ST), basalt (BA), and polypropylene (PP) fibers and reinforced with steel, GFRP, and CFRP bars of identical diameter and embedment. Under a uniform curing regime, the HFRC reached a compressive strength of approximately 82 MPa and exhibited a high fracture energy G_f approximately 3.7 kJ/m² with a stable post-peak response in a notched-beam test, demonstrating effective multi-scale crack bridging within a dense hybrid fiber network. Pull-out tests on 200 mm embedment revealed distinct interfacial mechanisms: ribbed steel developed a pronounced peak bond stress (τ_max = 13.05 MPa) and the largest bond energy (G_b = 146 N/mm) due to mechanical interlock, whereas smooth GFRP and CFRP showed low τ_max (=1.46 and 0.78 MPa) and smoothly decaying τ–s governed by adhesion–friction with G_b = 3–4 N/mm. A consistent experimental framework enabled direct mechanistic comparison of bond–slip behavior across reinforcement types without confounding matrix or curing variables. Simple constitutive laws calibrated to the experimental τ–s curves (ramp–softening for steel and ramp–plateau or exponential for FRP) captured the stiffness, strength, and energy hierarchy with low error. The main contribution of this study lies in providing a configuration-consistent reference dataset and calibrated bond–slip descriptions for hybrid-fiber HPC members reinforced with both steel and FRP bars. The results highlight the role of the hybrid fiber network in improving crack stability and provide design-oriented parameters for anchorage assessment and nonlinear bond–slip modeling. Although the results are based on a limited experimental program, they establish a mechanistically coherent basis for further optimization of hybrid HPC matrices and development of performance-based anchorage formulations in high-performance structural applications. Full article

Laminated bamboo (LB) has emerged as a promising sustainable structural material due to its rapid renewability, high strength-to-weight ratio, and favorable mechanical performance. Drawing on a comprehensive review of over 90 published experimental and analytical studies, this paper provides a critical synthesis of the structural behavior of LB, with emphasis on its compression, tension, flexure, shear, and creep responses. Reported mechanical properties exhibit variability, largely influenced by bamboo species, fiber orientation, processing methods, adhesives, lamination quality, and loading configuration. While LB demonstrates high tensile and flexural strengths comparable to or exceeding conventional timber products, pronounced anisotropy and brittle failure modes are consistently observed, particularly under shear and rolling shear loading. Recent studies on cross-laminated bamboo (CLB) highlight the significant role of interlaminar behavior and adhesive performance in controlling failure mechanisms, indicating that rolling shear capacities often govern the design of planar elements. Beyond mechanical behavior, this review synthesizes available research on thermal and fire performance. Emerging research on LB connections indicates that joint behavior often governs global structural performance, with strength and ductility strongly influenced by fastener type and embedment behavior. Key knowledge gaps are identified, underscoring the need for unified design frameworks to enable broader structural adoption of laminated bamboo systems. Full article

This study investigates the acoustic emission (AE) response and damage mode characteristics of ±45° glass fiber-reinforced polymer (GFRP) composites used in wind turbine blade shear webs under quasi-static tensile loading. It aims to establish the relationship between AE features and three typical damage mechanisms—matrix cracking, interfacial debonding, and fiber fracture—to support damage assessment and structural health monitoring. Quasi-static uniaxial tensile tests with synchronous AE monitoring are conducted on specimens with three orientations (0°, 45°, and 90°). AE features are selected using correlation analysis and principal component analysis, and the HAC-initialized K-means clustering method is employed for damage mode identification. The optimal number of clusters is determined to be three, according to the Davies–Bouldin index (DBI) and the Silhouette index (SI). The resulting low-, mid-, and high-frequency clusters are associated with matrix cracking, interfacial debonding, and fiber fracture, respectively. These interpretations are further supported by wavelet-based time–frequency analysis and microscopic fracture surface observations. Full article

Meat quality serves as a pivotal determinant of consumer purchasing behavior and of the economic viability of the livestock industry; as such, research into its regulatory mechanisms is of critical significance for the development of modern agriculture. Traditional investigations into meat quality have predominantly centered on sensory and physicochemical assessments of ultimate phenotypic traits, thereby facing inherent limitations in systematically deciphering the intricate molecular regulatory networks underlying meat quality formation. By contrast, an integrated analysis of the transcriptome and metabolome effectively connects the cascade of “gene transcription—metabolic regulation—phenotypic determination,” which has emerged as a core methodological paradigm in contemporary research on the molecular mechanisms governing meat quality. This review systematically delineates the evolutionary trajectory and principal technological frameworks of meat quality evaluation systems, with a focused synthesis of recent advances achieved through combined transcriptomic and metabolomic analyses in the field of meat quality regulation. The scope of this review encompasses core transcriptional regulatory networks associated with meat quality attributes, pivotal metabolic pathways, signal transduction mechanisms, and protein degradation dynamics. Furthermore, the regulatory impacts exerted by genetic variation among breeds, nutritional modulation, rearing environments, and stress responses on meat quality characteristics are comprehensively elucidated. Integrative analysis reveals that combined transcriptome–metabolome approaches transcend the inherent limitations of single-omics investigations, systematically unraveling the hierarchical regulatory mechanisms governing fundamental meat quality traits, such as muscle fiber type differentiation, postmortem glycolytic progression, intramuscular fat deposition, and flavor compound accumulation. Such integrative strategies have facilitated the identification of functional genes and metabolic biomarkers with potential utility for the early prediction of meat quality outcomes. Concurrently, this review acknowledges persistent challenges confronting the field, including the absence of standardized protocols for multi-omics data integration, insufficient functional causal validation, and a discernible disconnect between research discoveries and practical industrial implementation. Building upon this comprehensive assessment, prospective directions for future multi-omics research in meat quality are proposed, accompanied by the formulation of an integrated end-to-end improvement framework spanning fundamental research, technological innovation, and industrial application. Collectively, this review provides a systematic theoretical foundation for the in-depth elucidation of mechanisms that determine meat quality and the precision-oriented regulation of quality-determining traits in livestock production practices, thereby offering substantial scientific guidance for quality improvement initiatives within the animal husbandry sector. Full article

Numerical predictions of the wrinkling behavior of biaxially fiber-reinforced elastomer sheets are carried out under consideration of finite deformations. The Holzapfel–Gasser–Ogden material model is used to account for the anisotropic hyperelastic material behavior of the sheets, where material parameters are identified based on experimental data of tensile tests from literature. A Finite Element Method-based simulation strategy is presented to extract critical loading conditions and to access the postbuckling response using geometrical imperfections. Depending on the layup and aspect ratio of the sheets, wrinkling onset was predicted for global stretches between 10% and 25%. For sheets with fiber orientations [±45°] wrinkling is predicted at larger global stretches than for sheets with fiber orientations of $[+{30}^{\circ }/-{60}^{\circ }]$ for the same aspect ratio. Furthermore, it is shown that short sheets have a tendency towards symmetric wrinkling patterns whereas for long sheets asymmetric wrinkles are more likely to occur. Comparison of the numerical predictions with experiments from the literature shows that the geometrical characteristics of the wrinkles, such as wavelengths and amplitudes, can be well predicted. Far into the postbuckling regime, the deviations of the predicted wrinkling amplitudes and their experimental counterparts are around 30% or less. Full article

This study proposes a novel semi-discrete model of non-ordinary state-based peridynamics. It is used to simulate the tensile failure process of dog bone-shaped specimens of 3D-printed fiber-reinforced concrete with 0%, 1% and 2% fiber volume fractions. The results are compared with the literature laboratory results to verify the feasibility and reliability of the approach. In addition, it is utilized for a 3D-printable engineered cement-based composite (ECC) disk splitting simulation. Effects of different fiber lengths, printing interfaces, and fiber orientations on the failure process of disc specimens are investigated. It is found that ductile failure appears in the loading direction, while brittle failure appears in the other direction. Effect of fiber length on the bearing capacity is feeble. In addition, the non-ordinary state-based peridynamics semi-discrete model is used to simulate the crack propagation of three-point bending. The principal stress contours, damage diagrams, and displacement–load curves of the concrete matrix at different time steps during the crack propagation process are obtained. The simulation is in great agreement with the experimental results. Finally, it is demonstrated that the novel non-ordinary state-based peridynamics approach proposed in this paper is accurate and efficient to simulate fracture behavior of 3D-printed ECC beams. Full article

The effect of structure on the properties of cotton fibers is yet to be fully understood even after many years of research. This is due to the presence of convolutions that occur at various intervals in cotton fibers. An attempt was made in this investigation to remove these convolutions using liquid ammonia treatment. The optical and X-ray orientation angles of two varieties of G. hirsutum cotton fibers were investigated at various stages of maturity, and results were compared. An American upland variety was also studied. Four-hour treatment of cotton fibers in liquid ammonia at a temperature of −50 °C ensures a complete change of the lattice structure from cellulose I polymorph to cellulose III polymorph. The cellulose I lattice structure is restored by boiling it in distilled water for 24 h. X-ray diffractograms confirm these conversions. Mature fibers after treatments are devoid of convolutions and are rounded in appearance with no central lumen. The scanning electron micrographs revealed these morphological structures. A close correlation exists between the optical and X-ray orientation measurements and are both strongly dependent on fiber maturity. In all the varieties studied, a maturity ratio of at least 0.8 is required for a cotton fiber to be of commercial value, in terms of strength and durability The progressive build-up of both the primary and secondary walls as the fiber matures shows a gradual decrease in helix angles and, hence, an increase in the orientation of the fibrils, conforming to the constant pitch model. The effect of convolutions on both the optical and X-ray orientation angle is found to be higher than 10%. Full article

The research presented in this work focuses on the structural optimization of a multilayer CFRP (carbon fiber reinforced polymer) laminate integrated within a railway carbody frame. The primary objective is to implement a systematic design methodology aimed at achieving significant mass reduction while preserving the mechanical performance and safety margins required by railway standards. To this end, a multi-stage optimization framework was developed to explore the sensitivity of fiber orientation on the laminate’s failure behavior, directly coupled with high-fidelity finite element models for objective performance extraction. The investigation was initially conducted using an asynchronous optimization strategy, where the orientation of each individual ply was decoupled and analyzed independently. This phase revealed that a tailored, ply-specific approach is essential to address the varying structural requirements across the laminate thickness. Through this methodology, an optimal sequence of 36°/54°/126° was identified, achieving a significant 40.83% reduction in the Tsai–Wu failure index compared to a standard 0°/0°/0° baseline. Subsequently, a synchronous rotation analysis was performed to compare these results against conventional single-orientation design strategies. While the synchronous optimum was identified at 54°, it yielded a lower failure index reduction of 24.81%. The comparison highlights a further 16% performance gain enabled by the asynchronous method. Finally, the validation confirmed that these in-plane improvements were achieved without compromising interlaminar integrity, as the interlaminar shear stress (ILSS) remained constant and safe. This framework provides an objective and rigorous tool for the railway industry, replacing empirical design methods with a high-performance, data-driven approach. Full article

This study presents a calibrated analytical micromechanical framework for predicting the linear elastic behavior of unidirectional glass fiber/epoxy and carbon fiber/epoxy composites over a wide range of fiber volume fractions. The approach combines the classical rule of mixtures for the longitudinal Young’s modulus with the semi empirical Halpin–Tsai equations to estimate the transverse Young’s modulus and the in-plane shear modulus. The framework is specifically formulated to support durability-oriented composite design through rapid and physically consistent estimation of elastic properties governing load transfer and stress distribution. Material parameters, including fiber and matrix Young’s moduli (Ef, Em), shear moduli (Gf, Gm), Poisson’s ratios (νf, νm), and fiber volume fraction (Vf up to 0.80), are taken from established material property databases and implemented within a literature-informed modeling scheme. To preserve physical realism at high fiber contents, a shear correction factor is introduced for Vf > 0.50 to account for microstructural interaction and fiber clustering effects. The predicted effective elastic constants (E₁, E₂, G₁₂, ν₁₂) exhibit consistent and physically meaningful trends across the full fiber volume fraction range. The model predictions were evaluated against trends widely reported in the composite micromechanics literature, and the results showed overall agreement in the nonlinear reduction in stiffness gains at elevated fiber volume fractions. Comparative results indicate that carbon fiber/epoxy composites achieve up to approximately 30% higher stiffness than glass fiber/epoxy systems at equivalent fiber contents, reflecting the influence of stiffness contrast on composite response. The analysis further indicates that stiffness saturation begins approximately in the Vf = 0.60–0.70 range, where the incremental gains in E2 and G12 become noticeably smaller for both composite systems. This behavior provides design-relevant guidance by showing that, beyond this range, further increases in fiber content may offer limited stiffness improvement relative to the associated manufacturing complexity. Overall, the calibrated Halpin–Tsai methodology offers a practical and computationally efficient tool for preliminary evaluation and design-stage optimization of the elastic performance of high-performance composite structures. Full article

This study investigates the shear performance of reinforced concrete (RC) beams strengthened with near-surface-mounted (NSM) carbon fiber-reinforced polymer (CFRP) ropes under ambient and elevated temperature conditions. An experimental program comprising twelve RC beams was conducted, including both normal- and high-strength concrete specimens. The beams were strengthened using CFRP ropes installed at two orientations (45° and 90°) and two spacing configurations (150 mm and 200 mm). Ten specimens were exposed to a temperature of 600 °C prior to shear testing. The experimental results were evaluated against finite element (FE) simulations and shear strength predictions obtained from ACI 440.2R provisions. The FE models demonstrated close agreement with the observed experimental response, whereas ACI 440.2R consistently yielded conservative shear strength estimates, particularly for high-strength concrete beams. The results confirm that inclined CFRP configurations and reduced rope spacing significantly enhance shear capacity, even after severe thermal exposure, with measured strength gains reaching approximately 75% relative to unheated control beams and up to 135% compared to heated control specimen. The findings emphasize the sensitivity of NSM CFRP in terms of strengthening effectiveness to elevated temperature and highlight the limitations of existing design provisions when applied to fire-damaged RC members. Full article