Search Results (494)

Glass-transition-driven shape memory polymers are promising materials for 4D printing because their thermally activated transition enables programmed deformation and recovery without relying on melting or crystallization-driven switching. In this study, PDMS-MMA-modified photocurable networks were designed for vat photopolymerization-based 4D printing by varying PDMS-MMA content and switching monomer structure while maintaining a fixed TMPTMA crosslinker content. The resin formulations were prepared using tert-butyl acrylate (tBA) or isobornyl acrylate (IBOA) as switching monomers, PDMS-MMA as a flexible mobility-regulating segment, and TMPTMA as a multifunctional crosslinker. The effects of formulation composition on printability, network formation, thermal stability, thermomechanical transition, mechanical properties, and shape memory behavior were systematically investigated. FT-IR analysis confirmed effective photocuring of the acrylate/methacrylate networks, while rheological evaluation showed that resin viscosity depended on monomer structure and PDMS-MMA content. DMA results revealed thermomechanical transition, although some formulations exhibited broad tan δ responses due to network heterogeneity and distributed segmental relaxation. Based on resin printability, printed-part resolution, and relatively well-defined tan δ transitions, T-15 and I-15 were selected as representative formulations for quantitative shape memory evaluation. Shape memory testing was conducted under force-control mode because stable strain-controlled programming was not achievable for the printed specimens. Both T-15 and I-15 exhibited high shape fixity over two programming–recovery cycles. I-15 showed stable recovery behavior with recovery ratios of 91.51% and 95.87%, whereas T-15 showed apparent over-recovery with recovery ratios exceeding 100%, likely due to residual stress release during reheating. Overall, these results demonstrate that thermally activated shape-memory performance is governed not only by the nominal transition temperature but also by the coupled effects of PDMS-mediated segmental mobility, switching monomer structure, mechanical integrity, and elastic energy storage within a fixed crosslinked network framework. Full article

Autonomous driving sensor fusion housings (SFHs) integrate LiDAR, radar, camera, and computing modules within a shared mechanical and thermal enclosure. This review examines how coefficient of thermal expansion (CTE) mismatch among housing polymers, aluminum heat spreaders, substrates, and solder joints can contribute to interfacial delamination, solder joint fatigue, optical misalignment, and Thermomechanical Coupling Interference (TMCI). Using a structured narrative review of 99 publications and authoritative standards from primarily 2009 to 2026, the article organizes the evidence into a 4 × 4 taxonomy linking four failure mechanisms with experimental, computational, AI/ML, and qualification-oriented approaches. The review explicitly distinguishes direct literature evidence, transferred package-level evidence, model-based extrapolation, and author-derived conceptual estimates. Accordingly, TMCI temperature increments, sensor spacing values, optical drift estimates, and lifetime projections are discussed only as case-specific screening-level hypotheses unless directly validated in the cited literature. Five research gaps are identified: standardized multi-sensor TMCI validation, aging-corrected material and solder fatigue databases, long-term qualification of thermally conductive nanocomposites, SFH-specific validation of physics-informed digital twins, and integrated multi-failure testing. The contribution of this article is therefore primarily structural and agenda setting: it clarifies what is supported by direct evidence, what is transferred from adjacent domains, and what remains to be validated before robust SFH-level reliability guidance can be established. Full article

Al-50 wt% Si alloy is widely used in aerospace and electronics but is hard to machine owing to uneven microstructure. To elucidate the relationship between force–thermal coupling effects and surface integrity during Al-50 wt% Si alloy milling, this paper established a stress model to reveal the superposition mechanism of mechanical and thermal stresses. Experiments were conducted to investigate the evolution of cutting forces and temperatures, as well as their influence on surface integrity characteristics, including microhardness, roughness, and chip morphology. The results showed that temperature increases steadily with v_c, whereas cutting force fluctuates in an irregular manner. The maximum cutting temperature rises by 85.04% as v_c increases from 25 m/min to 125 m/min. Meanwhile, the thermo-mechanical coupling effect exerts a regulatory role on chip morphology, where higher v_c improves chip continuity and ductility. Surface integrity is determined by the competitive interplay between work hardening and thermal softening, and the surface microhardness varies from 168.49 HV to 173.27 HV. Specifically, elevated v_c optimizes surface quality, with the Ra decreasing by 24.54%, whereas excessive f_z and a_p aggravate damage. Ultimately, surface defects arise from the combined removal behavior of Si particles and deformation of the Al matrix, while the inhomogeneous stress field induces subsurface damage. Full article

This study presents multi-objective geometric optimization of a modular friction disk cutter for spur gear thermo-friction processing within the ANSYS Workbench 2024 R1. The integrated workflow—Geometry → Steady-State Thermal → Static Structural → Design of Experiments → Response Surface → Response Surface Optimization—enables selection of a rational tool geometry within a single parametric model. Variable dimensions (a, b, c) describe the load-bearing part: a characterizes the transitional thin profile zone, b is the massive supporting part, and c is the intermediate disk thickness controlling thermo-mechanical load transmission. Dimension c most significantly influences equivalent stresses and directional deformation, while maximum temperature depends on combined a and c effects. Based on Response Surface Optimization, the rational solution domain is concentrated near $a\approx 3 \mathrm{m}\mathrm{m}$, $b\approx 10 \mathrm{m}\mathrm{m}$, and $c\approx 4 \mathrm{m}\mathrm{m}$, yielding $P4\approx 33.306 \mathrm{M}\mathrm{P}\mathrm{a}$, $P5\approx 295.93 °\mathrm{C}$, and $P6\approx -5.7488·{10}^{-5} \mathrm{m}$. These values demonstrate a sufficient calculated safety margin within the finite element framework, providing a technically justified direction for prototype manufacturing. Although currently evaluated as purely computational without direct full-scale physical measurements, these results establish a foundation for subsequent experimental validation using thermal imaging and optical deformation analysis. Future research will focus on transient thermo-mechanical modeling with impulse cooling and experimental verification. Full article

Tesla valves have emerged as promising passive flow-regulation devices for sustainable water systems because they provide directional flow control without moving parts, external energy input, or complex maintenance requirements. This review systematically examines the fundamental mechanisms, structural evolution, and engineering applications of Tesla valves in water-related systems. The underlying rectification behavior is analyzed from the perspectives of flow separation, recirculation, jet interaction, vortex evolution, and mechanism switching under varying hydraulic conditions. Recent advances in geometric optimization, multistage configurations, three-dimensional architectures, topology optimization, and data-driven design approaches are summarized to illustrate the transition from classical Tesla geometries to next-generation passive flow-control structures. Current applications in microfluidic systems, water-quality monitoring, thermo-hydraulic devices, pressure-regulation networks, and hydraulic safety enhancement are critically reviewed. The analysis indicates that Tesla-valve performance is governed by coupled interactions among geometry, flow regime, fluid properties, and operating conditions, while multifunctional designs increasingly integrate flow regulation, mixing enhancement, heat transfer, and pressure management. Finally, key challenges related to performance standardization, realistic operating conditions, manufacturability, and system-level integration are discussed. Tesla valves are expected to play an increasingly important role in intelligent and energy-efficient water infrastructure, supporting the development of next-generation sustainable water and fluid-management systems. Full article

Offshore high-temperature steam flooding suffers severe steam channeling, uneven steam intake and low thermal efficiency, while conventional profile control agents fail to adapt to coupled harsh environments of 200–350 °C high temperature, ultra-high salinity and continuous steam shear. Existing reviews mainly focus on onshore thermal reservoirs or single foam/gel materials, lacking a targeted, gel-oriented systematic review matching unique offshore platform constraints. Guided by the integrated framework of “flow control–diversion–enhanced sweep efficiency”, this work establishes a six-dimensional quantitative screening standard and unified performance comparison database to systematically review foam, gel, particle, thermo-responsive and composite profile control systems. Differing from petroleum engineering-oriented summaries, this paper subdivides high-temperature gels into six categories from a polymer material perspective, elaborating their crosslinking mechanisms, thermal rheology and cyclic steam degradation rules; the inherent advantages, limitations and offshore applicable boundaries of each medium are quantitatively compared, with special emphasis on the unique “deep migration followed by in situ thermal activation” mechanism of thermo-responsive materials. Composite systems relieve single-material defects via multi-mechanism synergy yet face complicated on-site deployment barriers. Three core bottlenecks restricting field application are identified: the irreconcilable trade-off between deep propagation and stable plugging, large deviation between static aging results and dynamic anti-scouring performance, and exclusive engineering limitations of offshore platforms. A dedicated standardized dynamic laboratory evaluation scheme for cyclic steam flooding is proposed to narrow lab-field performance gaps. Future research priorities include salt-resistant thermally responsive composite gel modification, low-cost multi-component compound formula optimization, unified dynamic evaluation criteria and staged material matching guidelines to realize balanced performance of high-temperature tolerance, deep delivery and offshore operability. Full article

As semiconductor packaging technology evolves from two-dimensional to three-dimensional integration, the through-glass via (TGV) technique, as a core interconnect method in advanced packaging, is emerging as a strong candidate to replace through-silicon vias (TSVs) and plated through-holes (PTHs) in organic substrates. Glass substrates offer excellent electrical insulation, low dielectric loss, tunable thermal expansion coefficients, and the potential for large-scale panel-level manufacturing. However, issues related to TGV hole quality, metallization uniformity, and thermomechanical reliability remain key bottlenecks limiting their large-scale industrialization. This investigation provides a comparative review of non-laser and laser machining for TGVs to address the above problems. First, the technical background and core advantages of TGVs are outlined. Second, this study details non-laser processing methods, including sandblasting erosion, mechanical drilling, the photosensitive glass method, electrochemical discharge machining (ECDM), deep reactive ion etching (DRIE), and others. Third, laser processing methods, covering laser ablation drilling, laser-induced deep etching (LIDE), femtosecond laser-assisted wet etching and others, are given focus. Moreover, this study analyzes typical applications of TGVs in 3D/2.5D packaging, MEMS devices, optoelectronic integration, and others. In addition, the machining processes of non-laser and laser-based TGVs, such as mechanical machining, ECDM, and LIDE, are compared, and key process challenges, technical trade-offs, and reliability failure mechanisms are discussed. Finally, this review looks ahead to future trends, aiming to provide a systematic technical reference for researchers in the TGV field. Full article

This paper presents the development, fabrication, and characterization of a droplet-based microfluidic platform designed for precise local thermal treatment of cancer cells, with prospective chemical targeting as a future application. The workflow begins with a finite element model (FEM) using COMSOL Multiphysics 6.0 to characterize coupled hydrodynamic and thermal behavior, specifically analyzing temperature distributions across single-phase and three-phase regimes. Following the simulation, work has progressed to the fabrication of a microfluidic device and the characterization of its platinum heat source and temperature detector to ensure precise thermal control. To replicate realistic biochemical conditions, experiments have employed a three-phase configuration of oil, water, and fluorescent BSA solution. In the final stage, DX5-GFP MES-SA cancer cells have replaced the BSA solution to complete the measurements. To ensure reagent homogenization and consistent cellular exposure, a serpentine channel design was utilized to induce Dean vortices, which significantly enhanced internal mixing within the droplets. Fluorescence-loss experiments demonstrated that localized heating above ~60 °C induces irreversible thermal damage in both model proteins (fluorescent BSA) and cancer cells, establishing a proof-of-concept basis for precise thermal regulation at the single-droplet level. By deactivating specific thermo-sensitive proteins responsible for drug resistance, this integrated approach to thermal and hydrodynamic optimization enhances the efficacy of chemical stimuli and provides a robust platform for investigating the modulation of cellular defense mechanisms in future biotechnological applications. The platform holds significant potential for advancing precision oncology by enabling systematic, single-cell-level investigation of heat-shock-mediated drug sensitization, with long-term implications for overcoming multidrug resistance in aggressive cancer therapies. Full article

Energy pile groups present a dual-functional solution for structural support and geothermal energy utilization, yet their thermo-mechanical interactions with conventional piles remain insufficiently understood. This study establishes a 3D transient finite element model incorporating thermo-hydro-mechanical coupling to investigate thermal interference and differential settlement in hybrid pile groups under seasonal thermal loading. Systematic parametric analyses of pile length (10–30 m), diameter (1–2 m), and spacing (2D–3D) reveal two key findings: (1) Thermal perturbations in adjacent conventional piles exhibit distance-dependent attenuation characteristics, with measurable temperature variations (1–4 °C) observed within 4D spacing distances; (2) Differential settlement patterns demonstrate significant dependence on thermal operation modes, where heating cycles induce upward thermal stresses while cooling enhances consolidation settlement. The numerical framework is validated against field monitoring data and benchmarked with COMSOL 5.6/ABAQUS 6.14 simulations. Through optimized pile arrangements and spacing configurations, we demonstrate effective mitigation strategies for thermal interference and structural deformation, providing key guidance for the design of geothermal-energy-integrated foundation systems. Full article

Thermally responsive shape memory polymer materials are the most widely used type of intelligent materials and have found applications in numerous fields. However, their practical utility is often limited by poor heat conduction. Carbon nanotubes (CNTs), renowned for their exceptional thermo-conductive and photothermal properties, provide a promising solution. In this study, CNTs were integrated into polyurethane prepared by stepwise polymerization method, using hydroxyl terminated polycaprolactone (PCL-diOH), poly(ethylene glycol) (PEG) and hexamethylene diisocyanate (HDI). The resulting polyurethane composite material exhibits remarkable mechanical strength, enhanced thermal conductivity, and superior shape memory performance. Notably, it demonstrates a form of training enhancement phenomenon, which shows higher mechanical properties. And the composite could achieve stress-free two-way shape memory behavior after cyclic stretching process. Additionally, this composite material can exhibit “vitrimer” material properties at higher temperatures (110 °C), allowing for shape reprogramming. The carbon nanotube-reinforced composite material can achieve remote and precise manipulation under light stimulation. By combining the composite material with a metal thermally conductive layer, a multi-layer structure with shape memory properties can be prepared, which can achieve two-way shape memory behavior under electrical and light stimulation, further expanding the application potential of the composite material in the real world. Full article

Shape-memory polymers (SMPs) are gaining significant attention for their ability to recover predefined shapes via external stimuli. Among thermally activated systems, biodegradable blends of polylactic acid (PLA) and polycaprolactone (PCL) are particularly promising for biomedical devices and soft actuators. This study develops a thermo-mechanical theoretical model to investigate the shape-memory behavior of a PLA/PCL composite blend under controlled thermal cycling. The framework integrates transient heat transfer, temperature-dependent elasticity, and viscoelastic dynamics to predict temperature evolution, deformation, and internal stress. The thermal response is computed via Newton’s law of convection, while the mechanical transition is described by a sigmoidal temperature- and crystallinity-dependent Young’s modulus. Beam bending theory is employed to evaluate the spatial distribution of strain and stress. A parametric sensitivity analysis was performed to evaluate the influence of different parameters, including the crystallinity grade, convective heat transfer coefficient, glass transition temperature, and viscoelastic recovery constant. The theoretical study accurately reproduces the shape-memory cycle, quantifying performance through fixation and recovery ratios. This model provides a robust tool for the rational design and optimization of biodegradable smart polymer structures. Full article

Exploitation of deep (>4000 m) tight geothermal reservoirs is constrained by low native permeability and premature thermal breakthrough, limiting sustainable heat recovery. Here, we investigate THM (thermo–hydro–mechanical) controls on fluid flow and heat transport during cold-water reinjection in deep tight sandstone reservoirs through an integrated framework linking two-dimensional mechanistic analysis with three-dimensional field-scale modeling. A two-dimensional thermo-poroelastic model reveals that strong thermal contrasts induced by cold-fluid injection cause contraction of the rock framework and transient pore-space dilation under confinement, producing short-term permeability enhancement. This process alters local flow capacity and redirects early cold-front migration, with persistent impacts on subsequent heat transport. Field-scale simulations further quantify the coupled effects of well spacing and reinjection temperature on thermal breakthrough, defined as a 1 °C decline in production-well temperature. Increased well spacing delays cold-front arrival and significantly retards breakthrough, whereas lower reinjection temperature enhances early heat extraction but accelerates convective transport, leading to earlier breakthrough. The combination of thermally enhanced permeability and intensified convection promotes preferential flow channels, increasing breakthrough risk. Balancing thermal-breakthrough delay against the heat-extraction driving force, the simulations delineate a favorable engineering window for the investigated conditions and clarify how cooling-sensitive permeability evolution affects preferential flow and reservoir-scale thermal response. Full article

Thermal overload in internal combustion engines may progressively destabilize lubricant-film integrity and promote severe tribological deterioration within highly stressed contact interfaces. This study investigates the thermo-tribological degradation sequence of a high-mileage gasoline engine subjected to prolonged idle operation under impaired cooling conditions, ultimately resulting in engine seizure. The investigated engine had accumulated 356,724 km, while the lubricant had remained in service for approximately 26,724 km prior to the experiment. The post-failure investigation combined teardown inspection, geometrical camshaft assessment, reverse gravimetric reconstruction, hydraulic tappet surface profiling, XRF surface characterization, laboratory oil analysis, and SEM/EDS evaluation of wear debris. The results demonstrated strongly localized degradation concentrated primarily within the cam–tappet interfaces. Severe non-uniform camshaft wear was accompanied by pronounced hydraulic tappet surface damage and evidence of unstable boundary-lubrication conditions. Laboratory oil analysis revealed elevated wear-metal concentrations, depletion of the alkaline reserve, increased oxidation indicators, and a final Class D oil condition assessment. SEM/EDS characterization identified Fe-bearing wear debris associated with sustained material removal and debris recirculation during the final degradation stage. The combined evidence supports a coupled thermo-tribological degradation mechanism involving lubricant deterioration, boundary-lubrication instability, adhesive wear acceleration, oxidative surface degradation, and debris-assisted surface damage preceding final engine seizure. The present case study provides experimentally documented evidence of lubrication collapse under real-engine thermal runaway conditions and highlights the critical role of lubricant condition in maintaining tribological stability under severe thermal loading. Full article

The rapid growth of Deep Neural Networks (DNNs) has led to the development of application-specific DNN accelerators. Conventional 2D von Neumann architectures suffer from memory bandwidth limitations between the memory and the processing core. 3D DNN accelerators have emerged as a promising solution by leveraging 3D integration to enable near-memory logic or in-memory computation. By shifting computation closer to memory, these accelerators significantly reduce data movement and therefore latency, resulting in more energy-efficient operations. Monolithic 3D (M3D) integration, in particular, enables high-bandwidth systems by utilizing high-density monolithic inter-tier vias (MIVs). This paper provides a critical review of recent advances in 3D DNN accelerators that combine near-memory and compute-in-memory with various 3D technologies, offering a useful discussion and future prospects of the available technologies and architectures that have advanced the performance of DNN accelerators. Particular attention is devoted to accelerators for emerging transformer-based large language model (LLM) networks due to the higher memory demands. Thermal-aware design techniques of 3D DNN accelerators are also discussed as a means to address the fundamental challenge of heat dissipation. A detailed review is finally conducted on package-level constraints, considering signal integrity, power delivery, and thermo-mechanical reliability. Full article

Temperature and pressure are critical controlling parameters in the in situ conversion process (ICP) of oil shale. Clarifying the mechanisms governing organic matter pyrolysis is essential for reliably extrapolating laboratory findings to geological conditions. This review systematically summarizes the effects of temperature and pressure on shale pyrolysis and on hydrocarbon generation kinetics. Temperature is the primary factor controlling pyrolysis rates and product distribution, with an optimal temperature window enhancing shale oil yield while suppressing secondary cracking. Low heating rates favor thorough pyrolysis, although their influence on reaction pathways is generally overlooked in current kinetic models. Pressure effects are stage-dependent: during organic matter conversion, they are minor, whereas, in the product expulsion stage, high pressure inhibits hydrocarbon expulsion, prolongs residence time, and promotes secondary cracking, thereby reducing overall oil yield while increasing light fractions. Discrepancies in reported pressure effects arise from variations in experimental systems, sample forms, and medium conditions. The coupling of temperature and pressure is synergistic rather than additive. Given that current kinetic models largely neglect pressure and heating-rate effects, and that temperature–pressure coupling mechanisms remain unclear, future research should focus on thermal simulation experiments across wide ranges of pressures and heating rates, complemented by ReaxFF molecular dynamics to elucidate reaction pathways and guide kinetic model development. Further in situ experiments under high-temperature and high-pressure conditions are needed to characterize coupled pore evolution and fluid migration. Ultimately, integrated thermo-hydro-mechanical-chemical (THMC) models should be developed to capture hydrocarbon generation, retention, and expulsion, providing a robust theoretical framework for optimizing ICP technology. Full article