Search Results (4,412)

 Although polylactic acid (PLA) and acrylonitrile–butadiene–styrene (ABS) are among the most widely used polymers in material extrusion, their limited toughness and energy-absorption capacity often restrict the structural performance of 3D-printed functional components. To address the limited comparative understanding of how thermoplastic polyurethane (TPU) modifies the deformation behavior and phase characteristics of these two polymer systems, this study presents a multi-analytical evaluation of TPU-reinforced PLA and ABS blends. To this end, both polymers were blended with TPU at 10–50 wt% and processed into filaments via single-screw extrusion. The resulting filaments were used to fabricate ASTM D638 Type I tensile specimens via material extrusion under matrix-specific, but internally consistent, printing parameters. For each composition, five specimens were tested to obtain representative values of tensile strength, elongation at break, and toughness. In addition to conventional tensile testing, the evolution of strain during deformation was monitored using digital image correlation (DIC), enabling full-field characterization of local deformation behavior. To ensure experimental reliability, specimen masses were carefully controlled, and the datasets were analyzed using MATLAB. Thermal properties were investigated by differential scanning calorimetry (DSC) to determine the influence of TPU on glass transition, melting behavior, and phase mobility, and to relate these thermal characteristics to the mechanical response of the blends. The incorporation of TPU significantly increased ductility and energy absorption in both polymer matrices, although the magnitude of improvement differed. ABS/TPU blends exhibited the highest toughness enhancement, reaching 221.4% at 30 wt% TPU, while PLA/TPU systems showed nearly a twofold increase at 20 wt% TPU. DIC analysis further revealed a transition from localized brittle deformation in neat polymers to more distributed plastic deformation with increasing TPU content. DSC results indicated reduced crystallinity in PLA-rich blends and enhanced segmental mobility in ABS-based systems, consistent with the observed mechanical behavior. Overall, the combined mechanical, optical, and thermal analyses demonstrate that the optimal TPU content is matrix-dependent, providing practical guidelines for tailoring PLA- and ABS-based filaments to achieve a controlled balance between stiffness, ductility, and energy absorption in material extrusion applications.  Full article

In this work, the deformation behavior of a long-span steel–concrete composite girder cable-stayed bridge under temperature loads and its subsequent impact on ballastless track systems were investigated. An integrated finite element model (FEM) of the bridge–track system was developed by taking the Taiziping Wujiang River Bridge (with a main span of 300 m) in Chongqing, China, as a case study. The model incorporates composite girders, pylons, stay cables, rails, and double-block slab tracks. Then, the integrated FEM systematically analyzed structural responses to various temperature loading scenario, namely uniform temperature change, differential temperatures among key components (girder, deck, pylons, and cables), and deck–girder temperature difference. The results show that the girder’s maximum vertical displacement linearly correlates with the temperature variations of the composite girder, upper pylon, and cables, with corresponding temperature sensitivity coefficients of 2.3 mm/°C, 2.78 mm/°C, and −5.8 mm/°C. While the ballastless track coordinates well with the composite girder in vertical deformation, the maximum longitudinal relative displacement occurs between rail and track at the ends of the bridge. Moreover, field monitoring data were used to establish a high-precision relationship between ambient temperature and structural temperatures of key components, enabling successful prediction of girder’s vertical deformation. The findings provide a theoretical basis for the control of thermal deformation during the operation and maintenance of similar long-span composite girder cable-stayed bridges. Full article

Battery thermal management is critical for electric vehicles operating in cold climates, where low temperatures reduce battery efficiency, limit regenerative braking and accelerate degradation. This study compares PTC heater and heat pump systems for battery thermal management in electric minibuses using optimization-based control strategies. A control-oriented model of the vehicle thermal system, validated against chassis dynamometer measurements, and a heat pump system model, validated against testbed measurements, are used to optimize thermal management strategies via nonlinear programming, minimizing energy consumption while accounting for Joule losses, regenerative braking energy and thermal system consumption. Battery degradation is evaluated using a Doyle-Fuller-Newman (DFN) electrochemical model incorporating physics-based degradation mechanisms. Results show that optimized thermal management strategies can simultaneously reduce energy consumption and degradation. With the PTC heater system, only marginal improvements are achievable, and further reductions in degradation come at the cost of increased energy consumption. In contrast, the more efficient heat pump system enables simultaneous reductions in both degradation and energy consumption through optimized thermal management. These findings highlight that advanced thermal management leveraging heat pump systems can enhance both driving range and battery lifetime in cold-climate electric vehicle operations. Full article

Air curtain systems have been proposed as a supplementary smoke control strategy for vehicle tunnels, particularly where structural constraints limit the installation or upgrading of conventional ventilation systems. However, most previous studies rely on numerical simulations or fixed experimental facilities, while flexible experimental platforms and the influence of vehicle obstruction on smoke behavior remain less explored. This study experimentally investigates the smoke confinement performance of an air curtain using a 1:18 modular detachable scaled vehicle tunnel model. The modular configuration enables flexible assembly and adjustment of the experimental setup for different test conditions. A series of laboratory experiments was conducted using a liquefied petroleum gas (LPG) burner to simulate a vehicle fire. Temperature measurements and smoke visualization were performed under different air curtain jet velocities and vehicle obstruction conditions to analyze the interaction between the air curtain jet and buoyancy-driven smoke flow. The results show that the air curtain significantly restricts the upstream propagation of hot smoke and modifies the thermal field inside the tunnel. When the jet velocity reached approximately 5 m/s, the temperature in the protected region decreased by about 25–35% compared with the case without an air curtain. In addition, the presence of vehicle models altered the airflow structure and increased heat accumulation in the middle region of the tunnel cross-section. These results demonstrate that the proposed modular tunnel model provides a reliable experimental platform for tunnel fire research and highlights the importance of considering vehicle obstruction effects in tunnel smoke control studies. 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

Perovskite solar cells (PSCs) have quickly achieved certified energy conversion efficiency reaching a certified record of 27.3% for single-junction cells, while having a low mass, thin-film form factor and high specific power, which are attractive for space energy systems. However, their long-term reliability in extraterrestrial environments is not adequately ensured by terrestrial qualification routes, and standardized space-related test protocols remain insufficiently developed. This review critically summarizes the current understanding of the degradation of PSCs under the influence of key environmental factors in space—ionizing and non-ionizing radiation, thermal vacuum exposure and thermal cycling, and ultraviolet radiation AM0, as well as atmospheric oxygen in low orbits. The central task of the work is to develop and justify the need to create specialized PSCs test protocols for space applications, since existing ground standards do not reflect the multifactorial nature and extreme orbital loads. It has been shown that thermal vacuum accelerates ion migration, interphase reactions, and degassing, while AM0 UV and atomic oxygen introduce additional photochemical and oxidative mechanisms of destruction; at the same time, stressors often act synergistically and are not detected by single-factor tests. Next, the limitations of the current IEC and ISOS are discussed and an approach to their expansion is formulated through the ISOS-T-Space and ISOS-LC-Space protocols, which integrate high vacuum, AM0 lighting, extended temperature ranges and controlled particle irradiation. It is concluded that the development and interlaboratory validation of such space-oriented protocols is a key condition for the correct qualification of PSCs and targeted optimization of materials and interfaces to meet the requirements of space energy. Full article

Hydrogen absorption kinetics in metal hydride beds is constrained by coupled heat and mass transfer, which often leads to a slow refueling response and reduced storage system efficiency. In this work, hybrid molding by mixing silicone gel with various thermally conductive additives was used to prepare TiMn-based metal hydride beds with tailored porosity and thermal conductivity. Three experimental groups were prepared: 5 wt.% silicone gel and 5 wt.% single-walled carbon nanotubes (Group A), 5 wt.% silicone gel only (Group B), and 5 wt.% silicone gel and 5 wt.% silicone sheets (Group C). Hydrogen absorption kinetics at 30 °C and 50 bar were measured experimentally and simulated using a coupled heat-mass transfer model in COMSOL Multiphysics. The physical property results showed that Group A exhibited approximately threefold higher porosity (0.527) compared with the other two groups, while its thermal conductivity (2.476 W·m⁻¹·K⁻¹) was the lowest among them (3.189 W·m⁻¹·K⁻¹ for Group B and 3.246 W·m⁻¹·K⁻¹ for Group C). These property differences led to distinct hydrogen absorption rate-limiting behaviors. Group A dominated in the diffusion-controlled stage (hydrogen uptake between 0.5 and 1.15 wt.%) due to enhanced hydrogen transport through its macroporous network, while Group C exhibited faster kinetics in the later stage (above 1.15 wt.%), where thermal conductivity governed the absorption driving force. Numerical simulations reproduced the experimental kinetic curves and confirmed the transition of rate-limiting mechanisms. This work reveals that the rate-limiting factors of hydrogen absorption in hybrid molding hydride beds vary across different stages, and that independent optimization of porosity and thermal conductivity is required to achieve rapid kinetics across the entire absorption process. Full article

Concrete structures are highly vulnerable to fire exposure, which accelerates the degradation of mechanical properties and may lead to partial or total structural failure. Externally bonded carbon fiber-reinforced polymer (CFRP) systems are widely used for post-fire strengthening; however, the bond behavior at the interfaces between CFRP and fire-damaged concrete, particularly under different cooling conditions, is not yet fully understood. In this study, the bond behavior was investigated experimentally and theoretically. Double-lap joint tests of thirty-nine specimens were conducted, including three unheated control specimens and thirty-six specimens exposed to temperatures of 200 °C, 400 °C, and 600 °C for durations of one and two hours. Two cooling methods, natural air cooling and water cooling, were applied prior to CFRP bonding. The results indicated that bond strength increased under exposure conditions of no more than 400 °C, whereas a significant reduction was observed at 600 °C. Water cooling resulted in lower bond strength compared with air cooling, while longer exposure durations improved bond performance under certain thermal conditions. The reasons behind the phenomena were analyzed in detail. Based on the experimental results, an analytical model for predicting the bond strength at the interfaces between fire-damaged concrete and CFRP sheets was developed. The model can account for the effects of peak temperatures, exposure durations, and cooling methods, and demonstrated high predictive accuracy (R² = 0.94). The findings provide valuable insight into CFRP–concrete interaction after fire exposure and offer practical guidance for the assessment and rehabilitation of fire-damaged concrete structures. Full article

The ultra-precision machining of micro-optics from low glass transition temperature (T_g) hydrophobic polymers is frequently compromised by thermal instability and kinematic constraints imposed by on-axis turning. To address these challenges, this study presents a novel clamping–cooling system engineered for the off-axis diamond turning of low-T_g polymers. The design integrates vacuum clamping for workpiece stabilization with an embedded microchannel network for efficient thermal management. Strategic material selection effectively balances thermal insulation with mechanical stability. Performance evaluations demonstrated robust thermal regulation: lens blank surface temperatures stabilized at 6 °C during stationary testing, and the system was able to drop below 0 °C under maximum cooling targets. This strict thermal control enabled achieving nanometer surface roughness. Ultimately, this modular system facilitates the scalable, simultaneous production of high-quality, polishing-free intraocular lenses (IOLs), advancing manufacturing capabilities for complex precision optics. Full article

Thermoplastic polyurethane properties are governed by the interplay between soft-segment mobility, hard-segment interactions, and segmented morphology, yet the extent to which atomistic predictions of their thermal and mechanical behavior depend on force-field choice remains insufficiently benchmarked. Here, we combine FTIR, DSC, TGA, and tensile testing with all-atom molecular dynamics simulations to investigate HDI–PEG polyurethane systems across a controlled soft-segment series. Experimentally, films with PEG molecular weights of 400, 1000, and 1500 g/mol were characterized, while simulations were extended to 400–2000 g/mol to compare two complementary force-field frameworks under a consistent protocol: OPLS-AA, a conventional atom-type-based force field, and OpenFF/Sage, a direct-chemical-perception framework augmented here with bespoke torsional refinements. Both force fields reproduce the composition-driven decrease in Tg and density with increasing PEG length, but differ systematically in absolute values, with OPLS-AA predicting higher densities and Tg values than OpenFF. Tensile experiments show the highest elastic modulus for PEG400, a marked decrease at PEG1000, and a partial recovery at PEG1500. Although nanosecond-scale deformation simulations overestimate absolute moduli because they probe high-rate elastic response, they recover composition-dependent stiffness differences, with OpenFF yielding a more pronounced non-monotonic trend than OPLS-AA. Overall, this work provides an experimentally anchored benchmark for assessing which composition-driven trends in HDI–PEG polyurethanes are robust across force-field families, and which observables remain sensitive to model assumptions and simulation scale. Full article

This paper presents a deterministic embedded control architecture for an industrial electroplating line. The validated system includes two autonomous trolleys, 18 station-aligned process positions, shared-track motion, and redundant grouped baths. The proposed controller addresses the limitations of rigid sequential automation by combining asynchronous finite-state trolley execution, runtime allocation of equivalent technological stations, dwell-time-preserving retrieval, distributed thermal supervision, and layered fail-safe protection within a single ATmega2560-based implementation. The core contribution is the integration of virtual process groups and temporal FIFO logic into a compact plant-side embedded controller. This enables adaptive bath selection and process-completion-based retrieval without reliance on a real-time operating system or a computationally heavy supervisory runtime. The architecture also incorporates predictive pre-start validation, runtime software arbitration, hardware-wired interlocks, binary-coded trolley positioning, and a distributed 1-Wire thermal measurement network. Validation was performed in a controller-centered hardware-in-the-loop representation of an 18-station zinc electroplating line. Over a 100-batch horizon, the proposed architecture reduced makespan from 1642 min to 1244 min, corresponding to a 24.2% throughput improvement. Average trolley idle time decreased from 18.4 min/batch to 4.1 min/batch. Grouped-bath utilization increased from 64% to 91%, while tracked bottleneck incidents decreased from 18 to 2. These results show that adaptive, resource-aware, and safety-layered electroplating control can be realized effectively on a compact embedded platform in an industry-representative HIL setting, while preserving dwell-time integrity and controller-level safety invariants. Full article

The large-scale generation of industrial waste salts (IWSs) across sectors such as coal chemical, pesticide, pharmaceutical, and dye manufacturing has raised increasing environmental and regulatory concerns. These IWSs often exhibit complex physicochemical profiles—featuring high concentrations of inorganic salts, persistent organic pollutants, and trace heavy metals—that pose significant challenges for both safe disposal and resource recovery. This review provides a comprehensive and pollutant-oriented overview of industrial waste salts, focusing on their sector-specific characteristics, dominant contaminant types, and tailored treatment strategies. Removal pathways for organic matter (e.g., thermal decomposition, advanced oxidation) and inorganic impurities (e.g., precipitation, ion exchange) are systematically analyzed, followed by technical pathways for salt separation based on crystallization and membrane processes. Resource utilization routes for major salt components, particularly NaCl and Na₂SO₄, are critically assessed in terms of technical feasibility, impurity tolerance, and end-use compatibility. The emergence of reclaimed salt quality standards and sector-specific impurity thresholds reflects a paradigm shift from purity-based to performance-based reuse evaluation. Finally, the review highlights future priorities including adaptive impurity control, downstream-specific salt grading, and enforceable regulatory frameworks to ensure the safe, scalable, and circular deployment of reclaimed salts in industrial systems. This study supports the coordinated advancement of control technologies and reuse standards, enabling the transformation of waste salts from environmental liabilities to secondary resources. Full article

Astaxanthin (AST), despite its high bioactivity, exhibits poor stability and low bioavailability due to its strong lipophilicity and inherent degradation susceptibility. To overcome such a challenge, we developed a food-grade oleogel delivery system using a soy protein–arabinoxylan (SA) glycosylated complex modulated by different concentrations (0.5–3%) of sucrose ester (SE) or soy lecithin. We show that the emulsifier concentration has a non-linear effect on the oleogel microstructure: an optimal level of 1% had a significant impact on the interfacial compactness and network density, giving rise to improved thermal stability, rheological strength and AST encapsulation efficiency (81.27%). During in vitro digestion, the SA matrix in combination with emulsifiers allowed gastric protection and intestinal-targeted release of AST with a bioaccessibility of up to 88.84% (SAO-SE-AST). This controlled release profile directly translated into enhanced in vivo antioxidant efficacy in wild-type Bristol N2 Caenorhabditis elegans, as evidenced by reduced lipofuscin accumulation, elevated thermotolerance (survival rate: 64.44–73.33%), suppressed reactive oxygen species levels and activation of endogenous antioxidant enzymes (superoxide dismutase as well as glutathione peroxidase). Collectively, this research has uncovered that food-grade emulsifiers are not only stabilizers, but also key regulators of oleogel architecture and bioactive functionality. These results provide a structure–digestion–bioactivity correlation for protein–polysaccharide oleogels, representing a rational design strategy for high-performance delivery systems of lipid-soluble nutraceuticals. Full article

Wire Arc Additive Manufacturing (WAAM) has gained attention as a metal additive manufacturing process producing complex large-scale components with high deposition rates and lower costs. Cold Metal Transfer (CMT) offers reduced heat input and enhanced control of metal transfer, making it suitable for aluminium. This review analyses CMT-based WAAM with a focus on Al–Si alloys, providing a synthesis for this material system and establishing a structured comparison of representative studies on process fundamentals, arc mode variants, and key processing parameters. The influence of electrical and kinematic parameters and thermal management on process and geometrical stability, microstructural evolution, defect formation, and mechanical behaviour is discussed. Process behaviour is governed by the temporal distribution of heat input within the CMT cycle and thermal history. Control of heat input can reduce porosity, microstructural heterogeneity, and geometric instability, while advanced CMT modes can improve process stability and material efficiency under appropriate process configurations. Mechanical performance depends on the interaction between process parameters, microstructure, and defects, leading to variability and anisotropy. Despite progress, challenges related to process repeatability, narrow processing windows, defect susceptibility, and predictive capability remain. Future research should focus on parameter optimization, integrated modelling, real-time control, and WAAM-specific alloys to enable reliable industrial implementation. Full article

Enhanced geothermal systems (EGS) are a key technology for developing deep geothermal resources, yet they face significant challenges in constructing efficient thermal reservoirs within high-stress, high-strength, and low-permeability crystalline rock formations. Traditional hydraulic fracturing (HF) techniques encounter deep challenges in these environments, including excessively high fracturing pressures, limited fracture network patterns, and the risk of induced seismicity. This paper reviews the multi-scale thermal-mechanical mechanisms, fracture evolution patterns, and control strategies associated with thermal stimulation and permeability enhancement in the modification of deep geothermal reservoirs. Research indicates that thermally induced fracturing triggers intergranular and transgranular cracks at the microscopic scale due to mineral thermal expansion mismatches, which macroscopically manifests as nonlinear degradation of rock strength and modulus. The redistribution of the thermal elastic stress field significantly lowers the breakdown pressure, while matrix thermal contraction increases fracture aperture, leading to an exponential enhancement of permeability following a cubic law. However, the high confining pressure constraints, true triaxial stress anisotropy, and thermal short-circuiting risks present substantial suppression and challenges to the effectiveness of thermal stimulation in deep in situ environments. Different fracturing media, such as water, liquid nitrogen (LN₂), and supercritical CO₂, exhibit varying advantages in thermal stimulation efficiency due to their unique thermal-flow characteristics. Future research should focus on the thermal-mechanical coupling mechanisms under true triaxial stress conditions, and develop intelligent control strategies for permeability enhancement and thermal short-circuiting risk mitigation. This study synthesizes existing analyses and proposes potential engineering strategies for stimulating deep EGS reservoirs, offering significant strategic value for the development of geothermal energy as a baseload renewable resource. Full article