Search Results (1,363)

In this study, warm shot peening was applied to Ti-Al coatings to investigate its effect on high-temperature oxidation behavior at 800–1000 °C. WSP induced severe plastic deformation and thermal effects, resulting in grain refinement, increased lattice distortion, and TiAl-to-Ti₃Al phase transformation, thereby enhancing the structural stability of the coating matrix. Cyclic oxidation kinetics revealed a two-stage process transitioning from reaction-controlled to diffusion-controlled behavior. WSP delivered prominent protective effects at intermediate temperatures, substantially reducing oxidation weight gain and rate constants by promoting the formation of dense, stable Ti₂O₃ and Al₂O₃ protective layers with finer, more uniform oxide-scale morphology. However, this beneficial effect progressively weakened with increasing temperature and sharply diminished at 1000 °C, where massive generation of porous, thermally unstable TiO₂ dominated the oxidation process. The loose TiO₂ structure provided channels for inward oxygen diffusion, offsetting the microstructural optimization advantages of WSP and compromising oxide-scale barrier effectiveness. These findings establish a clear structure–performance correlation for WSP-modified Ti-Al coatings and elucidate the temperature-dependent failure mechanism of surface modification under ultra-high-temperature oxidation conditions. Full article

The incorporation of bio-derived modifiers in bitumen binders presents a practical pathway toward sustainable, carbon-sequestering road pavement infrastructure. This study evaluates commercially produced ECHO2 softwood biochar as a modifier for Australian viscosity-graded C170 bitumen, combining microstructural, thermal, physical, and rheological characterization to assess its suitability as a high-temperature reinforcing modifier. In this study, biochar was incorporated at 3%, 6%, 9%, and 12% by weight, utilizing particles smaller than 75 µm to maximize interfacial interaction. Characterization via SEM-EDS, XRD, and TGA revealed a highly stable, carbon-rich, amorphous material with a rough, porous morphology, favourable for physical interlocking with the bitumen matrix. Physical and rheological investigations demonstrated that ECHO2 biochar measurably enhances binder stiffness and high-temperature deformation resistance. Compared with the control, 12% biochar modification reduced penetration by approximately 27% and increased the softening point by approximately 10%, indicating a reduction in temperature susceptibility. Dynamic shear rheometer (DSR) temperature sweeps highlighted substantial increases in the complex shear modulus (G*) and rutting factor (G*/sinδ) without altering the phase angle (δ), confirming the modifier acts as a rigid, particulate reinforcing agent rather than an elastomer. Multiple stress creep recovery (MSCR) testing supported these findings; non-recoverable creep compliance (J_nr) decreased progressively. Critically, under the AASHTO M 332 specification, while the neat bitumen binder barely met the standard traffic (S) criteria, the progressive reduction in J_nr (particularly at 12%) delivered a substantially higher factor of safety against rutting within the standard traffic designation. Finally, ECHO2 biochar demonstrates strong potential as a sustainable modifier that restricts viscous flow through particulate stiffening, enhancing high-temperature rutting resistance at elevated temperatures. Full article

This study presents an initial effort to develop Low-Temperature Cofired Ceramics (LTCC) using local bio-sourced materials: Saint Jacques shells and slate tiles. Chemical analysis confirms that the Saint Jacques shells provide CaO and CaCO₃, while slate supplies the needed SiO₂ and Al₂O₃. The constituents, processed from a formulation targeting 70 wt% slate and 20 wt% shell fragments are crushed and ball-milled, mixed with 10 wt% boron trioxide (B₂O₃), and calcinated at 700 °C for two hours to remove organics, followed by a second milling. An aqueous slurry is then prepared and manually tape-cast to form tapes that are processed through standard LTCC process steps. Initial green-state mechanical tests showed elongation values up to ~7.8% and tensile break forces in the range of ~0.5–1.0 N, with lamination performed successfully using standard isostatic conditions. Cofiring yielded limited lateral shrinkage (~6%) but substantial vertical shrinkage (27%). Two-line method measurements indicate a relative permittivity of approximately 4.3 with a comparatively high loss tangent of 0.03, suggesting a vitreous phase and/or porous, inhomogeneous microstructure. A final resonator prototype is fabricated, yielding somewhat encouraging results for the feasibility of this bio-sourced LTCC route while highlighting the need to reduce dielectric losses in future work. Full article

Laser powder bed fusion (LPBF) produces microstructural anisotropy that influences hydrogen transport and passive film stability, yet the mechanistic relationship between build orientation, passive film chemistry, and corrosion behavior remains insufficiently understood. This study investigates how LPBF build orientation governs hydrogen-assisted passive film degradation by correlating electrochemical behavior with passive film chemistry. Additively manufactured 316L stainless steel specimens were fabricated in two build orientations, horizontal (0°) and vertical (90°), and subjected to electrochemical hydrogen charging for durations ranging from 2 to 36 h. Corrosion behavior was evaluated using open-circuit potential (OCP), electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR), and potentiodynamic polarization (PDP), while X-ray photoelectron spectroscopy (XPS) was employed to characterize hydrogen-induced changes in passive film chemistry. The electrochemical response showed that hydrogen charging progressively reduced the corrosion resistance of both build orientations. However, the degradation exhibited a non-monotonic dependence on charging duration, with intermediate charging durations suggesting transient repassivation before renewed deterioration during prolonged hydrogen exposure. EIS analysis revealed a substantial decrease in the fitted total resistance (R_total = R_ct + R_po), from 1.44 to 0.27 kΩ cm² for the 0° specimens and from 4.23 to 0.55 kΩ cm² for the 90° specimens. Potentiodynamic polarization showed that prolonged hydrogen charging increased the corrosion current density from 20.99 to 98.91 μA cm⁻² for the 0° specimens and from 0.79 to 46.86 μA cm⁻² for the 90° specimens. XPS analysis revealed progressive depletion of protective oxide species (Fe₂O₃, Cr₂O₃, Mo oxides, and lattice oxygen) together with enrichment of hydroxide-rich species, resulting in a lower O²⁻/OH⁻ ratio and transformation of the passive film into a more porous and less protective surface layer. These chemical changes were more pronounced in the 90° build orientation and were consistent with the greater reduction in passive film stability observed from the electrochemical measurements. The combined electrochemical and XPS analyses establish that LPBF build orientation governs hydrogen-assisted corrosion through its influence on microstructural anisotropy, hydrogen transport, passive film chemistry, and the resulting electrochemical response, providing mechanistic insight into the corrosion behavior of additively manufactured 316L stainless steel in hydrogen-containing environments. Full article

The steep radial temperature gradients developed in UO₂ fuels during reactor operation can drive pore migration, making pore–grain boundary (GB) coupled migration an important mechanism governing microstructural evolution. Although pores are generally regarded as pinning features that hinder GB migration, the conditions under which mobile pores retard, co-migrate with, or promote GB migration remain poorly understood. In this study, we develop a phase field model coupling vapor-transport-driven pore migration and curvature-driven grain growth to investigate the coupled migration behavior between intergranular mobile pores and GBs. The simulations first focus on an idealized source-term-free system to isolate the effect of pore–GB migration coupling from irradiation-induced pore generation and growth. The results show that the effect of pores on GB migration depends on the relative migration rate of pores and GBs, which is determined by both the pore-to-GB mobility ratio and the corresponding driving-force ratio. When pores migrate more slowly than GBs, they retard GB migration and exhibit an effective pinning effect. In contrast, sufficiently mobile pores can co-migrate with GBs and promote apparent GB migration when the pore migration rate exceeds that of the GBs. Furthermore, to illustrate the regulating effect of pores on GB migration in UO₂ under a temperature gradient, we perform additional simulations under continuous irradiation, in which pores nucleate spontaneously, migrate along the temperature gradient, and interact with GBs, in agreement with experimental observations. Based on the simulated GB migration behavior, we construct a regime map that distinguishes pinning/retardation, weak interaction, and pore-assisted migration regimes. This work provides a mechanistic phase field interpretation of pore–GB coupled migration and offers insight into microstructural evolution in porous oxide fuel materials. Full article

Aluminum metallic foams are lightweight porous materials characterized by low density, high stiffness, and remarkable energy absorption capacity. The mechanical performance of these materials strongly depends on the microstructure of the metallic matrix and the porous structure. In this study, closed-cell A356 aluminum foams were produced by the Alporas melt-foaming method using barite (BaSO₄) as a thickening agent and calcium carbonate (CaCO₃) as a foaming agent. The effect of grain refinement on the microstructure and energy absorption behavior under quasi-static compression was investigated. Grain refinement was evaluated by adding four concentrations of Al-5Ti-1B master alloy (0.02, 0.05, 0.08, and 0.10 wt.%) to the unrefined foam. The addition of Al-5Ti-1B reduced the secondary dendrite arm spacing (SDAS) from 41.85 µm to a minimum of 32.96 µm at 0.05 wt.%, producing stronger and more homogeneous cell walls that increased the plateau stress from 0.525 to 1.549 MPa and the energy absorption capacity from 0.299 to 0.735 MJ/m³—improvements of 195% and 145%, respectively. The energy absorption efficiency analysis confirmed that any refiner concentration improved the compressive performance compared to the unrefined foam. In addition, the energy absorption efficiency (E) and the ideality energy absorption efficiency (I) confirm that the refinement of the dendritic structure through Al-5Ti-1B addition strengthens the foam cell walls, improving their mechanical behavior and performance as an energy-absorbing material under quasi-static compression. Full article

Selective laser melting (SLM) can effectively suppress metallurgical defects inherent to conventional manufacturing; however, subsequent aging treatments essential for engineering applications introduce secondary precipitates that alter the electrochemical homogeneity of the matrix. The underlying mechanism by which such precipitation behavior governs corrosion resistance remains elusive. In this study, a Fe-30Mn-8Al-1.5C-2.5Ni steel was investigated to elucidate the corrosion morphology and electrochemical behavior of the as-built, 450 °C-aged, and 750 °C-aged specimens during immersion in a 3.5 wt.% NaCl solution. The results demonstrate that the inherent Mn microsegregation and high-density subgrain boundaries induced by SLM trigger preferential localized anodic dissolution on the surface of the as-built sample, culminating in the formation of a loose, porous manganese oxide product layer. Aging treatment at 450 °C induces extensive precipitation of κ-carbides within grain interiors and along grain boundaries, accompanied by localized depletion of Al and Mn at the phase interfaces. A pronounced micro-galvanic coupling established between the κ-carbides and the adjacent Al-depleted zones directly compromises the continuity of the passive film, thereby further deteriorating the corrosion resistance. In contrast, aging at 750 °C relieves the residual stress and eliminates the as-built elemental microsegregation. The resulting compositional homogenization of the matrix reduces the localized electrochemical driving force, which promotes a uniform reaction of Al at the surface to construct a continuous, compact Al-rich passive film, thereby sustaining the highest charge-transfer resistance during long-term immersion. This work elucidates the correlation among the intrinsic defects of SLM, aging-induced solute-depleted zones, κ-carbide precipitation, and localized micro-galvanic corrosion, providing a fundamental basis for tailoring the microstructure and corrosion resistance of additively manufactured lightweight steels. Full article

The growing demand for sustainable construction materials has encouraged the development of waste-based alkali-activated foams (AAFs) with enhanced thermal performance. This study investigates the use of roof tile waste (RTW) and marble waste (MW) for producing lightweight AAFs and evaluates the influence of aluminum (Al) powder on material performance. The novelty of this study lies in combining binder optimization, systematic evaluation of Al-induced pore evolution, and quantitative sustainability assessment within a single experimental framework. RTW was partially replaced with MW to optimize the binder, followed by the incorporation of Al powder (0–0.20 wt%) as a foaming agent. In an alkaline medium, metallic Al released H₂ gas, generating the porous structure of the AAFs. Physical, mechanical, thermal, microstructural, and material-based environmental properties were evaluated. In the binder optimization stage, 30% MW increased the compressive strength from 5.57 to 15.50 MPa. During AAF production, increasing Al content reduced dry-state thermal conductivity from 0.99 to 0.09 W/m·K, although excessive Al promoted pore coalescence and strength loss. The optimum 70RTW:30MW:0.15Al mixture exhibited a unit weight of 0.56 g/cm³, a dry-state thermal conductivity of 0.15 W/m·K, a compressive strength of 3.12 MPa, 79.9% waste incorporation, and 65.9% lower material-based embodied carbon than an ordinary Portland cement (OPC)-based reference binder, demonstrating its suitability for lightweight non-loadbearing wall applications. Full article

Against the backdrop of China’s dual-carbon strategy and the development of green transportation, systematic research on direct pavement carbon absorption and sequestration remains limited. Traditional epoxy resin coatings, owing to their dense structure, poor air permeability, and single functionality, fail to meet the requirements for pavement carbon absorption. To address this issue, an ordered, honeycomb-like, porous epoxy carbon-absorbing coating was prepared using bisphenol A epoxy resin as the matrix and diethylenetriamine as the curing agent through the breath-figure method. The pore-formation mechanism and the process regulation principles of the coating were systematically elucidated. Key preparation parameters (ambient humidity, dispersion concentration, and spray dosage) were regulated, and multiple microscopic characterization methods, including SEM, FTIR, and TG, were adopted to comprehensively explore the influences of preparation parameters on the coating’s microstructure, chemical composition, and thermal stability. Experimental results indicate that under optimized process conditions, a honeycomb-like porous coating with uniform pore size and regular arrangement can be fabricated. The fabrication procedure features simple operation, favorable controllability, and low cost. The breath-figure method was successfully applied to the preparation of a porous epoxy carbon-absorbing coating, achieving controllable regulation of the porous structure and thereby effectively overcoming the limitations imposed by the dense nature of traditional epoxy coatings. Consequently, this work provides new technical concepts and data support for the development and application of low-carbon functional coatings for pavements. Full article

Protein-rich polysaccharides are increasingly recognized as multifunctional biopolymers with significant biomedical potential. In this study, a protein–polysaccharide complex (JrPRP) was isolated for the first time from the root bark of Juglans regia L. and comprehensively characterized. JrPRP was obtained with a yield of 4.7% (w/w) and exhibited an acidic composition enriched in uronic acid-related components, together with minor neutral sugars. Spectroscopic analyses (FTIR and UV–Vis) confirmed the coexistence of carbohydrate and protein domains, while chromatographic profiling (TLC and HPLC) indicated a heterogeneous monosaccharide composition. Scanning electron microscopy revealed a porous and irregular microstructure, consistent with a structured biopolymeric network exhibiting pronounced anionic character. Functionally, JrPRP demonstrated notable antioxidant activity, with IC₅₀ values of 405 ± 1.8 µg/mL (DPPH), 225 ± 3.5 µg/mL (ABTS), and 229 ± 1.7 µg/mL (metal chelation), along with strong ferric-reducing capacity. The complex exhibited antibacterial activity against Pseudomonas aeruginosa, Klebsiella pneumoniae, and Staphylococcus aureus (MIC: 2–9 mg/mL), as well as potent antibiofilm activity, inhibiting up to 94% of Escherichia coli biofilm formation. Biocompatibility assays indicated low hemolytic activity, supporting its favorable safety profile. In addition, JrPRP showed moderate anticoagulant effects and strong anti-inflammatory activity, reaching 98% inhibition of protein denaturation, comparable to or exceeding diclofenac under similar conditions. These findings identify J. regia root bark as a promising and previously underexplored source of structurally distinctive uronic acid-containing protein-rich polysaccharides and provide new insights into the relationship between their compositional features and multifunctional biological activities. Full article

Magnesium-based materials remain among the most intensively studied solid-state hydrogen storage systems because they combine high theoretical hydrogen capacity, elemental abundance, and comparatively low cost. Yet their practical performance is still constrained by sluggish sorption kinetics, difficult hydrogen release, surface passivation, and transport instability under repeated cycling. This perspective argues that these long-standing limitations are most coherently understood not as isolated thermodynamic or kinetic problems, but as a multiscale hydrogen transport-network problem. In this view, hydrogen storage performance depends on whether hydrogen can be admitted, transferred, redistributed, and released through a sufficiently continuous and durable sequence of interfaces, phases, defects, and microstructural pathways. The discussion therefore moves from activated interfaces, which govern hydrogen entry, to phase-network engineering, in which alloying reorganizes internal transport connectivity, and then to hierarchical architectures, where porous hosts, scaffolded secondary phases, and multicomponent microstructures amplify transport efficiency across scales. The perspective further emphasizes that these material-internal transport advantages become meaningful only when they remain compatible with heat and mass transfer at the level of a working storage body and device. Possible descriptors, including active-interface density, connected phase fraction, effective diffusion length, pathway tortuosity, apparent network efficiency, and rate retention during cycling, are further discussed to make this framework more operational. On this basis, the article proposes that future progress in Mg-based hydrogen storage will depend less on isolated optimization of additives or descriptors and more on the deliberate design of connected hydrogen transport networks from the atomic and interfacial scales to the system scale. Full article

The impact of nonionic surfactant (Tween 20 and Tween 80) addition during the chopping process on the surimi gel quality was investigated. Results showed that the addition of Tween 20 or Tween 80 significantly decreased myofibrillar protein solubility in a dose-dependent manner. The surface hydrophobicity of myofibrillar proteins increased, likely due to the binding of surfactants. However, the added surfactants exerted a protective effect on myofibrillar protein denaturation, indicated by the greater intensity of intrinsic fluorescence and a higher proportion of ordered secondary structure. Forward-extrusion tests demonstrated that the surfactants reduced the cohesion and adhesion of the surimi paste, leading to improved uniformity and easier extrusion. For the heat-set surimi gel, addition of Tween 20 and Tween 80 led to a less compact, more porous microstructure, which ultimately led to reduced gel strength, hardness, and water-holding capacity. These findings showed that Tween 20 and Tween 80 can protect proteins against denaturation during chopping and improve the flowability of surimi paste, and the weakened mechanical strength of heat-set gel offered potential applications in developing specialized textured foods for the elderly. Full article

Drying is a key operation for extending the shelf life of agricultural products and maintaining food quality, and its efficiency and product outcomes are governed by coupled heat and mass transfer. This review critically summarizes the mechanisms, technological characteristics, research methods and application prospects of agricultural-product drying from a heat- and mass-transfer perspective. The moisture-migration pathways, including surface evaporation, internal diffusion, capillary flow, vapor diffusion and bound-water desorption, are first discussed within a porous-medium framework. Governing equations based on Fourier’s law, Fick’s law, energy conservation and convective transfer are then introduced to clarify the theoretical basis of drying models. Typical convective, radiative, conductive and combined drying technologies are compared in terms of transfer mechanisms, drying efficiency, energy consumption, product-quality retention, carbon-footprint potential and industrial feasibility. Particular attention is given to the effects of drying-induced heat and mass transfer on color, texture, rehydration, bioactive compounds, antioxidant activity and microstructure. Current theoretical, experimental, numerical and data-driven research methods are further reviewed, and the limitations of existing studies are identified, including simplified homogeneous assumptions, insufficient model validation, limited quantitative comparison and weak scale-up applicability. Finally, future directions are proposed, including refined multi-scale and multi-field coupled models, advanced in situ characterization, multi-energy-field synergistic drying, digital twins, predictive modeling and multi-objective intelligent optimization. This review aims to provide a more mechanism-based and application-oriented reference for developing efficient, low-carbon and quality-preserving drying systems for agricultural products. Full article

The growing demand for sustainable and environmentally friendly materials has accelerated interest in the valorization of industrial wastes within the framework of the circular economy. In this study, porous wollastonite-based ceramics were successfully fabricated using cement kiln bypass dust (CKD) and waste glass cullet as low-cost and sustainable secondary raw materials. The proposed approach aims to mitigate environmental pollution, reduce landfill disposal, conserve natural resources, and promote the recycling of industrial by-products into value-added ceramic products. Different batch compositions containing varying proportions of CKD and glass cullet were prepared, compacted, and subsequently sintered under controlled conditions to induce crystallization. The crystallization behavior and phase development were characterized by X-ray diffraction (XRD), while the microstructural features were examined using scanning electron microscopy (SEM). Physical and dielectric properties, including bulk density, open porosity, dielectric constant (ε′), dielectric loss (ε″), and electrical conductivity (σ), were also evaluated. The results confirmed the successful formation of parawollastonite as the predominant crystalline phase, accompanied by a relatively homogeneous porous microstructure. The prepared ceramics exhibited high open porosity values ranging from 52.55 to 63.63% and low bulk densities between 1.050 and 1.318 g cm⁻³, making them suitable for lightweight construction and insulation applications. Dielectric measurements performed over the frequency range of 50 Hz–8 MHz revealed that both dielectric constant (ε′) and dielectric loss (ε″) decreased with increasing frequency. At 50 Hz, ε′ and ε″ ranged from 8.44–9.39 and 0.709–0.733, respectively. The electrical conductivity values (~10⁻² μS cm⁻¹) at low frequencies indicated insulating behavior, whereas poor-to-fair semiconducting characteristics were observed at higher frequencies. The incorporation of large amounts of recycled CKD and waste glass significantly reduced dependence on virgin raw materials while providing a sustainable route for waste utilization. Consequently, this work demonstrated an environmentally responsible and economically viable strategy for producing porous wollastonite-based ceramics with potential applications in both the construction and electrical sectors, thereby contributing to resource efficiency, waste valorization, carbon-emission reduction, and sustainable industrial development. Full article

Impaired wound healing is often caused by persistent inflammation, bacterial infection, and insufficient extracellular matrix remodeling. Natural polymer-based hydrogels represent ideal wound dressings but often struggle to balance structural stability and biological activity. Herein, we report a dual-functional network regulation strategy enabled by highly soluble mussel foot protein (HMFP) that acts simultaneously as a structural crosslinking regulator and bioactive effector to fabricate synergistic hydrogels (CS-SH-H) from β-chitosan (CS) and sodium hyaluronate (SH). HMFP homogenizes the porous microstructure, strengthens intermolecular interactions, and significantly improves thermal and structural stability via multivalent non-covalent bonding. In vitro, CS-SH-H shows excellent cytocompatibility, significantly promotes fibroblast proliferation and migration, and exerts potent antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). In a mouse full-thickness skin defect model, the hydrogel dramatically accelerates wound closure, reducing the residual wound area to 25% on day 7, outperforming the control groups. Immunohistochemistry confirms that HMFP suppresses TNF-α-mediated inflammation and enhances Ki-67-positive cell proliferation, leading to accelerated re-epithelialization and collagen deposition. This study establishes HMFP as a promising marine-derived dual-functional network regulator for designing high-performance hydrogel dressings. This strategy is scalable and translatable for treating infected and inflammatory wounds. Full article