Search Results (1,497)

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

Mg–Y–Zn alloys have attracted considerable attention for lightweight structural applications; however, the influence of extrusion temperature on microstructural evolution and the underlying mechanisms governing strength–ductility synergy remains insufficiently understood. In this study, a novel YZG921 (Mg–9Y–1.8Zn–1.2Gd–0.5Zr–0.3Ca, wt.%) alloy was fabricated by hot extrusion at temperatures ranging from 480 to 520 °C. The microstructure, mechanical properties, and deformation behavior were systematically investigated using SEM, TEM, EBSD, in situ EBSD, and slip-trace analysis. The results show that extrusion temperature significantly affects the evolution of secondary phases, grain size, and texture intensity. At 500 °C, an 18R-LPSO phase was formed, accompanied by a more homogeneous distribution of secondary phases and the finest grain structure (~3.8 μm), whereas the average grain size remained close to 10 μm for the alloys extruded at 480 °C and 520 °C. Meanwhile, the maximum basal texture intensity decreased from 4.16 to 4.79 m.r.d. to 2.18–2.58 m.r.d. Mechanical testing revealed that the alloy extruded at 500 °C exhibited the optimum strength–ductility balance, with an ultimate tensile strength of 498.4 MPa and an elongation of 13.8%. In situ EBSD analysis showed that the fraction of low-angle grain boundaries increased from ~7% to 43% during tensile deformation, while the average KAM value increased from ~0.5° to 0.88°. Slip-trace analysis further demonstrated that plastic deformation was predominantly governed by basal slip, accounting for approximately 84.2% of the activated slip systems. The superior mechanical performance achieved at 500 °C is attributed to the synergistic effects of grain refinement, LPSO and second-phase strengthening, texture weakening, and sustained strain hardening. These findings provide insights into microstructure–property relationships and offer guidance for the optimization of thermomechanical processing parameters in Mg–Y–Zn alloys. Full article

The present study investigates the application of electric resistive heating to photovoltaic (PV) panels, aimed at enabling their subsequent thermo-mechanical delamination. The key process parameters—namely current magnitude and applied voltage—required for direct electro-resistive heating are identified, and the process is experimentally demonstrated under laboratory conditions. The electric resistive heating of a composite photovoltaic panel, consisting of a solar cell layer (crystalline silicon, c-Si, with a metallic grid), a backsheet, and a glass layer, is analyzed in detail using a virtual model of a single-crystal silicon solar cell implemented as coupled electric-thermal analysis. The temperature dependence of the electrical resistance of the solar cell layer is experimentally measured, and exponential relationships are derived and subsequently incorporated into the numerical model. The virtual model results are validated, demonstrating that, for a given geometry and configuration of the conductive metallic grid (busbars and fingers), the electrical resistance of the semiconductor layer containing the p–n junction governs the temperature achieved during electro-resistive heating as a function of the applied current. Furthermore, results for the terminal current and voltage, current density in the busbars and fingers, electric field intensity, and the resulting temperature within the semiconductor layer of the single-crystal silicon solar cell are presented and analyzed. Full article

We investigate the formation of surface periodic structures during ablation of a 20 nm aluminum film on a glass substrate by high-power terahertz pulses. Using subpicosecond pulses in the 0.5–3 THz range with a field strength of 15 MV/cm (fluence 0.3 J/cm²) generated in a DSTMS crystal pumped by a femtosecond Cr:Forsterite laser, we observe discrete growth of cone-shaped damage channels with a period of 20 µm at an energy density below the single pulse ablation threshold ($F_a\approx 0.15$ J/cm²). The channel length increases from pulse to pulse (for 8, 20, and 100 pulses) due to local current density enhancement at the channel tip. This enhancement scales inversely with the square root of the tip radius and reaches an order of magnitude. Surface morphology analysis reveals a thermomechanical mechanism governing film destruction. The observed self-organized periodic structures, whose orientation is strictly perpendicular to the THz electric field, hold promise for functional devices in the terahertz band, such as polarizers, near-field sensors, and spatially selective absorbers, provided the formation process can be regulated. Full article

Recent advances in chiplet architectures, heterogeneous integration, 2.5D/3D packaging, high-performance computing, and RF applications have increased the demand for high-density vertical interconnects and low-loss packaging platforms. Glass substrates have attracted considerable attention for next-generation advanced packaging because of their low dielectric loss, high dimensional stability, smooth surface, and compatibility with large-area panel-level processing. Through-glass vias (TGVs) are essential vertical interconnect structures that enable the electrical integration of glass substrates. This focused review summarizes TGV technologies for glass-based advanced packaging from the perspectives of via formation, seed layer deposition, metallization, Cu filling, defect formation, reliability, and plugging-based alternative architectures. Representative TGV formation methods, including laser drilling, selective laser etching, laser-induced deep etching, wet/dry etching, and photosensitive glass processing, are compared. Metallization approaches based on sputtering, electroless plating, ALD/CVD, and hybrid processes are discussed together with Cu electroplating strategies such as conformal plating, bottom-up filling, pulse or pulse-reverse plating, and engineered-geometry filling. Key defects, including voids, seams, pinch-off, seed discontinuity, Cu/glass interfacial delamination, glass cracking, and Cu protrusion, are reviewed in relation to thermomechanical reliability. Finally, polymer/dielectric plugging, plugging/re-drilling, conductive paste plugging, and hybrid Cu/plugging structures are discussed as application-specific alternatives for balancing electrical performance, reliability, manufacturability, yield, and cost. Full article

Residual stresses and distortions are critical challenges in laser beam powder bed fusion (PBF-LB) of Ti6Al4V components (PBF-LB/M/Ti6Al4V), impacting structural integrity and dimensional accuracy. This study assesses the inherent strain method (ISM) as a computationally efficient alternative to full thermomechanical simulations for predicting these effects. By integrating ISM with experimental validation via the contour method, the research provides specific insights into stress distribution patterns in geometries featuring stress concentrators such as notches. Results demonstrate a strong correlation between simulation and experimental data, particularly at the mid-height regions. Quantitatively, the orthotropic ISM successfully predicted the peak residual stress at 1101.4 MPa, showing excellent agreement within a 4% error margin against the experimental maximum of 1144 MPa captured via the contour method. These findings underscore how ISM can be effectively applied to practical engineering components to predict high-stress zones, enabling the design of distortion-compensated parts without the high computational cost of traditional models. Ultimately, this method facilitates more robust process optimization and enhances the quality and reliability of Ti6Al4V components manufactured via PBF-LB. Full article

The extreme thermal environment during the underground coal gasification (UCG) process poses a severe threat to the stability of the gasification cavity and the integrity of the surrounding rock. This paper aims to reveal the thermo-mechanical response characteristics and damage evolution mechanism of sandstone under true triaxial unloading conditions following exposure to high temperatures. Sandstone specimens were thermally pre-treated at five temperature gradients (25 °C, 200 °C, 400 °C, 600 °C, and 800 °C) and subsequently subjected to true triaxial loading and unloading experiments. The effects of varying temperatures on the strength, deformation parameters, dilation angle evolution, and macroscopic failure modes of the sandstone were systematically analyzed. The results indicate a significant critical transition point in the mechanical behavior of the sandstone at 400 °C. Below this threshold, thermal-induced microcrack closure leads to an increase in peak strength (with the peak strength at 800 °C increasing by approximately 67% compared to room temperature). Conversely, above 400 °C, thermal damage to the mineral grains intensifies, causing the crack propagation pattern to transition from brittle shear to a complex tension-shear splitting mode, accompanied by severe dilatancy (with a generalized Poisson’s ratio exceeding 0.8). Based on these findings, this study proposes a stage-wise damage evolution model alongside a targeted zonal support strategy, recommending the application of high-prestressed support in high-temperature zones above 400 °C to suppress tensile failure. Ultimately, this research provides a crucial theoretical basis for evaluating the long-term stability of high-temperature underground engineering projects and ensuring operational safety. Full article

Hot forging of Ti-6Al-4V is extensively utilized in the manufacture of orthopedic implants; however, the coupled influence of strain rate and temperature on ductile damage evolution during the forging of femoral stems remains insufficiently quantified. In this study, a finite element framework is developed to analyze and optimize the hot forging process, incorporating strain rate- and temperature-dependent plasticity, as well as the Johnson–Cook damage criterion. Mesh convergence is established, and the assumption of quasi-adiabatic conditions is substantiated via Péclet number analysis. A full factorial design is implemented by varying the ram velocity (0.1–0.5 m/s) and initial billet temperature (850–950 °C) to evaluate the forging load, stress triaxiality, equivalent plastic strain, and damage accumulation. Results indicate that process kinetics govern the mechanical response: increasing the ram velocity enhances strain-rate hardening, resulting in higher peak loads, while explicitly reducing stress triaxiality and suppressing ductile damage evolution. Conversely, temperature exhibits a secondary influence within the investigated domain. Validation of the damage criterion confirms safe operating windows, identifying low-velocity forging as a high-risk condition for localized defect formation. These findings provide practical guidelines for the strain-rate-based optimization of thermomechanical processing parameters for Ti-6Al-4V femoral stems. Full article

The optimization of Fused Filament Fabrication (FFF) process parameters is commonly performed using room-temperature mechanical properties as the main decision criteria, while the temperature-dependent thermomechanical response of printed polymers is often not explicitly considered. This limitation is relevant for functional components intended to operate above room temperature, where stiffness retention and viscoelastic behavior may strongly affect service performance. This work proposes an experimental–statistical framework for selecting FFF parameters by integrating Design of Experiments (DoE), tensile testing, dynamic mechanical analysis (DMA), Analysis of Variance (ANOVA), the Entropy Weight Method (EWM) and the VIKOR method. Two materials with contrasting thermomechanical behavior were investigated: a high-performance semicrystalline polymer, Z-PEEK, and an elastomeric thermoplastic, TPU 95A. For each material, a DoE was defined to evaluate the influence of key printing parameters, and the manufactured specimens were characterized in terms of maximum tensile force, maximum deformation and storage modulus at selected temperatures. The ANOVA results showed a material-dependent influence of the processing parameters, with thermally driven parameters being especially relevant for Z-PEEK and deposition-related parameters having a stronger influence on TPU 95A. The EWM–VIKOR analysis identified the optimal Z-PEEK configuration as 400 °C extrusion temperature, 200 °C build plate temperature and 150 °C chamber temperature, whereas the optimal TPU 95A configuration corresponded to 225 °C extrusion temperature, 0.10 mm layer height, 50 mm/s printing speed and 80 °C build plate temperature. Overall, the results demonstrate that incorporating DMA-derived thermomechanical indicators into MCDM-based optimization provides a more application-oriented basis for FFF parameter selection than approaches based only on room-temperature mechanical properties. Full article

Plantar orthoses play an important role in podiatric care, as they help to redistribute plantar loads, improve foot function, and support the treatment of various conditions, including diabetic foot disease. In this context, additive manufacturing has substantially expanded the capacity to produce customized orthoses through digital geometry acquisition, computational design, and controlled fabrication. From a biomimetic and bionic perspective, 3D-printed plantar orthoses can be understood as engineered interfaces that reproduce, support, or modulate key biomechanical functions of the human foot, including load redistribution, shock attenuation, adaptive stiffness, and gait stabilization. Additive manufacturing enables these biological and biomechanical principles to be translated into patient-specific devices through controlled geometry, graded structures, and material selection. Moreover, from a sustainability perspective, recycled polylactic acid (rPLA) has emerged as a material of potential interest for this type of application, not only because of its compatibility with 3D-printing processes but also because it offers the possibility of reusing polymer waste and reducing the consumption of virgin raw materials in devices whose service life may be limited. This review examines the conditional viability of recycled PLA for 3D-printed plantar orthoses by integrating direct clinical evidence on orthotic function with indirect technical evidence from material-level and process-level studies. The reviewed literature indicates that recycled PLA may offer environmental and economic benefits; however, repeated thermomechanical reprocessing may alter viscosity, dimensional consistency, crystallinity, interlayer adhesion, and mechanical reliability. Recent orthosis-focused studies show that extrusion-based technologies can be applied to customized insoles, lattice or internally reinforced structures, multimaterial systems, and emerging smart concepts; however, most of these developments still rely on virgin or ad hoc-designed materials rather than recycled feedstocks. Overall, the available evidence suggests that recycled PLA should not yet be regarded as a direct substitute for virgin PLA in plantar orthoses. At present, the evidence supporting the use of recycled PLA in plantar orthoses is predominantly indirect and technical rather than directly clinical. Its use appears technically promising, but its viability remains conditional and depends on feedstock traceability, control of the manufacturing process, the suitability of material properties for device function, and validation of the orthosis under clinical conditions. Full article

Accurate Remaining Useful Life (RUL) prediction of TFT-LCD modules is critical for industrial predictive maintenance, yet it remains heavily challenged by complex degradation mechanisms in different climates. Traditional purely data-driven models (SVR, LSTM) often lack physical interpretability, struggling to filter out environmental noise or predict irreversible failures. To address this, we propose a highly reliable prognostic tool based on a Physics-Informed Gaussian Process Regression (PI-GPR) framework, by embedding cumulative thermal load and thermo-mechanical stress into the model’s prior function. Evaluated using one-year field exposure data, the physical constraints empower the model to accurately predict device lifetime under highly variable environments, including luminance fluctuations in tropical hygrothermal conditions and device failures in cold environments. Quantitative results demonstrate that the unified PI-GPR framework achieves an outstanding coefficient of determination (R² = 0.93) and reduces the RUL prediction error to merely 7.5 days, significantly outperforming conventional shallow learning, deep sequence, and standard probabilistic baselines. Ultimately, this study provides a robust, physically grounded methodology for the health monitoring and life cycle management of display modules in practical industrial applications. Full article

The South African aluminium industry faces technical challenges related to cladded ingots used in automotive heat exchangers, creating a need for offline processing methods that can replicate rolling processes like roll bonding, as large-scale industrial trials are costly and difficult to control. To address this, Mintek established a comprehensive offline manufacturing facility for process and product development of rolled metal products, focusing on the thermomechanical processing of aluminium alloys. In this study, stacked AA4045/AA3003mod coupons were processed under controlled conditions by varying thickness reduction, temperature, and reheating, aiming to investigate the effect of isothermal soaking time on microstructure and mechanical properties. Tensile tests were performed on clad sheets before and after brazing heat treatment, and fracture surfaces were examined via scanning electron microscopy. Samples heated at 505 °C for ≥38 h, followed by cold rolling and annealing, fell at the lower end of the 9031-H24 specification for yield strength, which is important for this application (i.e., the minimum tensile yield strength of 145 MPa and the ultimate tensile strength (UTS) range of 190 to 230 MPa). Fracture surface analysis revealed a dimple-dominated structure in cold-rolled and annealed samples, indicating ductile fracture. The study concludes that the offline roll-bonding method successfully replicates industrial cladding processes, and that isothermal soaking duration significantly influences mechanical performance, though careful control of thermal exposure is necessary to meet the specified mechanical properties. Full article

Aluminum–lithium (Al–Li) alloys are widely used in aerospace applications because of their high strength-to-weight ratio and reduced density. However, their corrosion behavior can be significantly affected by thermomechanical processing and exposure to chloride-containing environments. In the present study, the corrosion behavior of AA8090-T3 Al–Li alloy was investigated in 3.5 wt.% NaCl solution under simulated marine conditions. The specimens were extracted from a plate and subsequently subjected to annealing and rolling treatments using a specially designed wedge-shaped geometry to generate a continuous strain gradient, enabling the evaluation of deformation-dependent corrosion behavior across different deformation zones. The corrosion behavior was evaluated using potentiodynamic polarization, immersion testing, and surface characterization techniques. The results revealed significant variations in corrosion behavior with thermomechanical condition and deformation zone. The T3 temper-rolled specimen exhibited superior corrosion resistance compared to the annealed and rolled conditions. The lowest corrosion rate of 0.003 mpy was observed for the highly deformed T3 temper-rolled condition, whereas annealed specimens showed higher corrosion susceptibility associated with localized corrosion attack and precipitate-related galvanic activity. Surface characterization confirmed the formation of aluminum hydroxide- and copper oxide-based corrosion products. The study demonstrates the effectiveness of the wedge-shaped rolling methodology for evaluating zone-dependent corrosion behavior in thermomechanically processed AA8090 alloy. Full article

Poly(L-lactic acid) (PLLA) is a biodegradable polyester that has garnered widespread attention for its potential applications as a replacement for conventional petroleum-based plastics. However, PLLA’s prolonged biodegradation is a significant limitation in its applications, particularly in single-use packaging, as it can lead to environmental accumulation and hinder the sustainability goals of reducing plastic waste. This paper examines the effect of incorporating thermoplastic chitosan (TPC) on the mechanical and biodegradation properties of PLLA. TPC was prepared using lactic acid as a plasticizer. PLLA/TPC composites were produced by thermo-mechanical processes. TPC contents of 1%, 2.5%, 5%, and 10% were investigated. The PLLA/TPC films exhibited distinct phase separation, as verified by scanning electron microscopy analysis. The incorporation of 2.5% TPC led to a 20.8% enhancement in elongation at break and a 7.4% improvement in tensile toughness relative to pure PLLA film. Nonetheless, both values diminished when the TPC content surpassed 2.5 wt%. The surface wettability of the PLLA/TPC films, assessed via water contact angle measurements and weight loss from soil burial tests, enhanced with greater TPC content. The PLLA/TPC films showed significantly greater weight loss after being buried in soil for 12 months compared to pure PLLA film. The increases in weight loss were 4, 11, 14, and 72 times greater for the TPC contents of 1%, 2.5%, 5%, and 10%, respectively. Incorporating TPC in this study improved the flexibility and biodegradability of PLLA, leading to PLLA-based composites with enhanced potential for environmentally sustainable single-use packaging. Full article

With the rapid development of clean and low-carbon energy systems, non-metallic pipelines have become increasingly important in urban gas distribution, water supply, and emerging energy-transport applications, including hydrogen service. As a critical joining technology that governs system integrity and long-term operational safety, electrofusion welding requires a comprehensive and mechanism-oriented understanding beyond empirical process control. In this study, a review is conducted on research published over the past decade in the field of electrofusion welding of non-metallic pipelines, with emphasis on fundamental technical issues including the formation and evolution of temperature fields, characteristics of the molten fusion zone and defect development, and thermo-mechanical coupling with residual stress generation. Based on a synthesis of the literature, the review clarifies the global research landscape, core research communities, and underlying knowledge structure. The results indicate a clear transition of the field from empirically driven parameter optimization toward a mechanism-based and process-controllable paradigm centered on temperature field evolution, fusion zone development, and thermo-mechanical behavior. Current research hotspots converge on HDPE material adaptability, welding process regulation, and the long-term reliability of welded joints. Building on these insights, future research directions are discussed, including mechanism-driven process design, intelligent defect identification based on multi-source data, and full-life reliability assessment under service conditions. This review provides a theoretical framework to support process optimization and engineering application of electrofusion welding in non-metallic pipeline systems. Full article