Search Results (52,042)

High-power microelectronic packaging faces critical thermomechanical failures under rapid thermal cycling, primarily due to interfacial stress concentration and warping in conventional homogeneous heat sinks. To address this challenge, this study proposes a novel functionally graded SiC/Al composite with a tailored thermal expansion coefficient (CTE) gradient, designed to achieve adaptive thermal expansion matching between the chip and heat sink. Through multiscale finite element analysis, the stress–strain behavior and warping characteristics of homogeneous (Cu and Al) and gradient materials were systematically investigated. The results show that the gradient SiC/Al design significantly reduces the peak thermal stress and maximum warping deformation. The progressive CTE transition effectively mitigates abrupt interfacial strain jumps and extends device lifespan under extreme thermal loads. This advancement positions gradient SiC/Al composites as a key enabler for next-generation high-density packaging and power electronics requiring cyclic thermal stability. The study provides both theoretical insights into thermomechanical coupling and practical guidelines for designing robust electronic packaging solutions. Full article

This study describes the development and characterization of materials based on activated carbon (AC). Pellets composed of dried biomass of willow, knotweed, and maple were formed and pyrolyzed to obtain different types of AC. Nickel (Ni) nanoparticles were synthesized on these materials using a bottom-up strategy by impregnating the carbons with a nickel nitrate solution. To characterize the surface and structure of these materials, SEM, MP-AES, and DSC-TGA techniques were employed. The ash content was analyzed to determine the input of mineral components in the carbons. The DSC-TGA results showed good thermal stability for each of the carbons, even at a temperature of 800 °C. BET analysis was also conducted, and the isotherms revealed well-developed surfaces for most of the specimens. The high efficiency of the impregnation process was confirmed by the MP-AES results: 165 mg of Ni was deposited on 1 g of carbon derived from maple leaves. The adsorbed Ni was well distributed across the carbon surfaces, as demonstrated in micrographs taken with the SEM-EDS apparatus. A comparison with similar materials reported in other studies was also performed. Full article

Three-dimensional reconstruction programs are essential tools for understanding the behavior of asphalt mixtures. On the basis of accurate 3D models, it is convenient to identify the complex relationship between spatial structures and physical properties. In this work, we explore a low-cost and data-efficient way to create a collection of 3D asphalt mixture models. The core idea is to introduce a foundational segmentation program and stochastic modeling into the asphalt mixture reconstruction framework. First, our approach captures a 2D image to present spatial structures of the investigated sample. The integration of a smartphone camera and an image quilting method has been designed to understand fine-grained details and facilitate full coverage. Aiming at realizing high-quality segmentation, we propose the Segment Anything Model (SAM)-driven method to distinguish aggregate grains and asphalt binder. Second, Multiple-Point Statistics (MPS) is activated to build 3D models from 2D training images. To speed up the reconstruction step, we apply Nearest Neighbor Simulation (NNSIM) to improve pattern searching efficiency. Aiming at calculating 3D conditional probabilities, the probability aggregation framework is introduced into the asphalt mixture investigation. Third, our program focuses on the modeling evaluation procedure. Determination of a two-point correlation function, analysis of distance and a grain size distribution assessment are separately performed to check the reconstruction quality. The evaluation results indicate that our program not only preserves spatial patterns but also expresses uncertainty during the material production step. Full article

A novel honeycomb with gradient-thickness cell walls (HGTCWs) is fabricated through chemical etching to achieve progressive thickness reduction in the cell walls. This engineered honeycomb demonstrates superior energy absorption by effectively eliminating the peak load during the linear elastic stage of the load–displacement curve under impact loading, thereby preventing premature structural failure caused by excessive instantaneous loads. To systematically investigate the impact compression mechanics, energy absorption characteristics, and key influencing factors of aluminum HGTCWs, a three-factor orthogonal array of low-velocity impact experiments was designed. The design of experimental parameters for the impact test has taken into account the impact mass, impact velocity, and etching height. Comparative analysis assessed how these factors influence energy absorption performance. Results reveal that chemical etching-induced thickness gradient modification effectively suppresses peak load generation. Load–displacement curves exhibit distinct bilinear characteristics: an initial single linear phase when compression displacement is below the etching height, followed by a dual-linear phase with an inflection point at the gradient height. Time–velocity profiles during impact primarily consist of an initial nonlinear deceleration phase followed by a linear deceleration phase. Range analysis and analysis of variance identify impact velocity as the dominant factor influencing the energy absorption characteristics of HGTCWs. Full article

Plasma Electrolytic Polishing (PEP) is an advanced anodic process that enhances stainless steel surfaces through controlled electrochemical dissolution and plasma-mediated modification. This study demonstrates that PEP treatment of AISI 304 SS at 300 V in aqueous urea solution (3.0 wt.%)/NH₄NO₃ (0.25 wt.%) achieves remarkable improvements: surface roughness decreases by 54.6% (from 0.197 ± 0.023 μm to 0.0895 ± 0.0205 μm) with minimal mass loss (0.0035 g·cm⁻²) in just 20 min. Tafel analysis showed a 99% reduction in corrosion rate (0.00497 mm yr⁻¹) compared to untreated AISI 304 SS (0.094 mm yr⁻¹). Cyclic Potentiodynamic Polarization (CPDP) measurements indicated superior pitting resistance (E_pit = +0.423 vs. +0.486 V for PEP processing). XPS analysis elucidates the underlying mechanisms, showing a 91% increase in the Cr/Fe ratio (0.44 to 0.84) and complete transformation of surface oxides to protective Cr₂O₃ (57.34 wt.%) and Fe₃O₄ (55.88 wt.%), which collectively explain the enhanced corrosion resistance. Full article

The interest in synthesizing new dielectric materials is caused by their potential application in various electronic and sensor devices as well as in a large variety of electronic components. The present work reports the synthesis of glasses in the Na₂O/Al₂O₃/BaO/ZrO₂/TiO₂/B₂O₃/SiO₂ system prepared by melt-quenching. These glasses were then crystallized to glass–ceramics by a controlled thermal treatment. X-ray diffraction experiments reveal the precipitation of Ba₂TiSi₂O₈ (fresnoite) and BaTiO₃, which probably forms a BaZr_xTi_1−xO₃ solid solution. The microstructure is studied by scanning electron microscopy and shows the presence of mulberry-shaped, crystallized structures with a densely-branching morphology. Microcomputed X-ray tomography is used to gather information on the volume fraction and average size of the crystallized volume as an effect of the applied temperature–time schedule. Longer annealing times lead to a higher volume fraction and increasing average size of the crystallization structures obtained. The dielectric properties analyzed by impedance spectroscopy are insulating and show relatively high dielectric constants ≥ 100 and moderate loss tangent values at 10 kHz. Full article

Grid-stiffened panels are indispensable in aerospace applications, valued for their lightweight nature, high strength, and excellent deformation resistance. However, the roll-bending forming process of these panels is plagued by critical defects such as rib buckling and uneven skin deformation, which undermine structural quality and performance. Fillers are commonly employed to mitigate these issues, yet there remains a lack of systematic guidance for optimizing filler parameters—particularly the elastic modulus—that is tailored to high-rib thin-web configurations. This study focuses on high-rib thin-web grid-stiffened panels, aiming to address this gap by exploring the optimization of filler elastic modulus. By delving into this critical parameter, the research seeks to lay the groundwork for enhancing forming precision in roll bending, offering valuable insights for advancing high-quality manufacturing of aerospace components. Full article

This study explores the critical role of airborne nanoparticle shape in air filtration performance, with direct relevance to the field of nanomaterials production. Aerosol particles ranging from 40 to 250 nm—including spherical Fe₂O₃, cubic MgO, straight rod-shaped ZnO, and curved or clustered COOH-functionalized nanotubes—were synthesized and tested to assess shape-dependent filtration behavior. The results indicate that the effect of particle morphology on filtration efficiency becomes markedly pronounced at larger particle sizes. For instance, at 250 nm, filtration efficiency differed by as much as 30% between spherical Fe₂O₃ and rod-shaped ZnO particles. These findings have substantial implications for industries engaged in large-scale nanomaterial synthesis, particularly where anisotropic or rod-like particles are prevalent. The potential for higher-than-anticipated atmospheric release of such particles underscores the need for refined environmental controls and monitoring. Furthermore, the current practice of using primarily spherical particles in air filter certification tests may require reconsideration to ensure accuracy and applicability to real-world scenarios involving non-spherical nanomaterials. Full article

Aiming to address the key challenges of poor enzyme stability, difficult recovery, and difficult synergistic optimization of catalytic efficiency in high-value conversion of biomass, this study utilizes mineralization self-assembly technology to combine laccase with Fe₃O₄@SiO₂-PMIDA-Cu²⁺ composite, constructing magnetic laccase nanoflower (MLac-NFs) materials with a porous structure and superparamagnetism. This synthetic material can efficiently catalyze the selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA). The characterization results indicated that MLac-NFs exhibit optimal catalytic activity (63.4 U mg⁻¹) under conditions of pH 6.0 and 40 °C, with significantly enhanced storage stability (retaining 94.26% of activity after 30 days of storage at 4 °C). Apparent kinetic analysis reveals that the substrate affinity and maximum reaction rate of MLac-NFs were increased by 38.3% and 439.6%, respectively. In the laccase–mediator system (LMS), MLac-NFs mediated by 30 mM TEMPO could achieve complete conversion of HMF to FDCA within 24 h. Moreover, due to the introduction of magnetic nanoparticles, the MLac-NFs could be recovered and reused via an external magnetic field, maintaining 53.26% of the initial FDCA yield after six cycles. Full article

Deep learning tools have recently shown significant potential for accelerating the prediction of microstructure–property linkage in materials. While deep neural networks like convolution neural networks (CNNs) can extract physics information from 3D microstructure images, they often require a large network architecture and substantial training time. In this research, we trained a graph neural network (GNN) using phase field generated microstructures of Ni-Al alloys to predict the evolution of mechanical properties. We found that a single GNN is capable of accurately predicting the strengthening of Ni-Al alloys with microstructures of varying sizes and dimensions, which cannot otherwise be done with a CNN. Additionally, GNN requires significantly less GPU utilization than CNN and offers more interpretable explanation of predictions using saliency analysis as features are manually defined in the graph. We also utilize explainable artificial intelligence tool Bayesian Inference to determine the coefficients in the power law equation that governs coarsening of precipitates. Overall, our work demonstrates the ability of the GNN to accurately and efficiently extract relevant information from material microstructures without having restrictions on microstructure size or dimension and offers an interpretable explanation. Full article

The incorporation of fly ash into concrete reduces cement consumption by 10–30%, lowers CO₂ emissions by 30–50%, cuts costs by 15–25%, and enhances durability, thus reducing maintenance expenses. However, the predictive model for the elastic modulus of fly ash concrete subjected to calcium leaching is still lacking. Regarding the theoretical method, the content of calcium hydroxide and calcium silicate hydrate in fly ash–cement systems is quantitatively calculated according to the hydration reaction relationship between cement, fly ash, and water, and then the porosity of the fly ash–cement matrix and interface transition zone (ITZ) after calcium leaching can be obtained. Based on the theory of two-phase composite spheres and the non-uniform ITZ model, the prediction method for the elastic modulus of leached fly ash concrete can be constructed, which comprehensively considers key parameters such as fly ash content, non-uniform characteristics of the ITZ, and the water–binder ratio (w/b). Additionally, the corresponding experimental investigation is also designed to study the variation regulation of the leaching depth, leaching extent, and elastic modulus of fly ash concrete with leaching time. The prediction method for the elastic modulus of leached fly ash concrete is validated via self-designed experimental methods and third-party experiments. This study further delves into the specific effects of w/b, aggregate volume fraction (f_a), fly ash content, and ITZ thickness (h_ITZ) on the elastic modulus of leached concrete (E). The research findings indicate that an appropriate amount of fly ash can effectively enhance the leaching resistance of concrete. For a leaching degree of 10.0%, 30.0%, and 50.0%, E at w/b = 0.40 exceeds that of w/b = 0.60 by 26.71%, 28.43%, and 30.28%, respectively; E at h_ITZ = 10 μm exceeds that of h_ITZ = 50 μm by 16.96%, 15.80%, and 15.11%, respectively; and E at f_a = 65% is 39.82%, 43.15%, and 46.12% higher, respectively, than that of concrete with f_a = 45%. Furthermore, a linear correlation exists between the elastic modulus and the degree of leaching. The prediction method for the elastic modulus offers a theoretical foundation for in-depth exploration of the durability of leached mineral admixture concrete and its scientific application in practical engineering. Full article

Acoustic emission (AE) testing is a non-destructive method used in various applications. In our work we demonstrate its capabilities and potential in studying the functional properties of physical vapor deposited (PVD) coatings. The goal was to classify the coating damage during indentation testing more objectively by quantifying specific imprint features. The AE response was systematically recorded in nine sample conditions and 27 individual imprints, allowing us to identify correlations between the numerical values derived from the SEM observations and the characteristics of the AE signal. An increase in the delaminated coating area was found to correspond to an exponential increase in the AE signal energy. These findings suggest that AE analysis could reduce the reliance on SEM-based evaluation and help accelerate systematic research in the field of PVD coatings. The advantages of AE testing are discussed and conclusions for practical applications are provided. Full article

This paper addresses the issue of reduced lifespan of coastal concrete piles due to chloride ion corrosion. A combination of concrete mix optimization and pile geometry improvement measures is proposed. Based on the diffusion coefficient optimization of Fick’s second law, the service life prediction of concrete piles in corrosive environments is completed. The results show that, compared to single slag incorporation and the “slag-fly ash” dual-component mix, the “slag-fly ash-corrosion inhibitor” triple-component concrete achieves a 28-day compressive strength of 67.4 MPa, and the chloride ion diffusion coefficient is reduced to 1.14 × 10⁻¹² m²/s, significantly improving overall performance. Finite element simulations reveal that, compared to ordinary square piles, cut-corner square piles can effectively alleviate stress concentration at the pile tip and reduce settlement. The maximum stress is 3.94 MPa, and the settlement is 22.64 mm, representing reductions of about 16.3% and 15.5%, respectively, compared to ordinary square piles. Concrete service life prediction confirms that the concrete with corrosion inhibitors has a predicted service life of 31.5 years, extending 7.4 years and 13.3 years longer than the single slag and the “slag-fly ash” dual-component groups, respectively. The “material-structure” optimization theory proposed in this study provides a theoretical basis and technical path for the long-life design of coastal engineering pile foundations. Full article

For future clean and renewable energy technology, designing highly efficient and robust electrocatalysts is of great importance. Particularly, creating efficient bifunctional electrocatalysts capable of effectively catalyzing both hydrogen- and oxygen-evolution reactions (HERs and OERs) is vital for overall water electrolysis. In this study, we employ 2D molybdenum disulfide (MoS₂) nanosheets and pyrolytically fabricated 2D graphitic carbon nitride (gC₃N₄) nanosheets to create 2D gC₃N₄-decorated 2D MoS₂ (2D–2D gC₃N₄–MoS₂) nanocomposites using a facile sonochemical method. The 2D–2D gC₃N₄–MoS₂ nanocomposites show an interconnected and agglomerated structure of 2D gC₃N₄ nanosheets decorated on 2D MoS₂ nanosheets. For water electrolysis, the gC₃N₄–MoS₂ nanocomposites exhibit low overpotentials (OER: 225 mV, HER: 156 mV), small Tafel slope values (OER: 49 mV/dec, HER: 101 mV/dec), and excellent durability (up to 100 h for both OER and HER) at 10 mA/cm² in 1 M KOH. Furthermore, the gC₃N₄–MoS₂ nanocomposites show excellent overall water electrolysis performance with a low full-cell voltage (1.52 V at 10 mA/cm²) and outstanding long-term cell stability. The superb bifunctional activities of the gC₃N₄–MoS₂ nanocomposites are attributed to the synergistic effects of 2D gC₃N₄ (i.e., low charge-transfer resistance) and 2D MoS₂ (i.e., a large electrochemically active surface area). These findings suggest that the 2D–2D gC₃N₄–MoS₂ nanocomposites could serve as excellent bifunctional catalysts for overall water electrolysis. Full article

Background: In adhesive dentistry, debonding-on-demand is attractive for situations where no permanent attachment is required. Due to its destructive nature, ultraviolet (UV) light may be of interest for attenuating bond forces. The aim of this study was to investigate the impact of UV light on the shear bond strength (SBS) of etch-and-rinse (n = 4) and universal adhesives (n = 3). Methods: Glass-ceramic samples were bonded to bovine enamel surfaces (n = 10/adhesive) and subjected to shear bond testing before and after exposure to UV light (320–390 nm, 126 Jcm⁻²). Data was statistically analyzed by Mann–Whitney U test. Results: Initial photopolymerized etch-and-rinse adhesives showed superior SBS compared to universal adhesives. Highest values were recorded for iBOND^® Total etch (15.48 MPa) and Syntac classic© (17.60 MPa). Lowest SBS was obtained for Ecosite Bond^® (2.63 MPa). Additional UV exposure caused a significant decrease in SBS among iBOND Total etch (5.24 MPa, p = 0.009) and Solobond M© (3.65 MPa, p = 0.005), while for Syntac classic©, an increase (24.12 MPa, p = 0.047) was recorded. Among all other tested adhesives, no significant changes were observed. Conclusions: UV radiation impacted SBS of etch-and-rinse adhesives only (decrease: iBOND Total Etch, Solobond M; enhancement: Syntac classic©). Further research should focus on introducing sufficient light-triggered debonding mechanisms. Full article