Search Results (443)

This study aimed to investigate the effects of cold storage time and matcha addition on the multi-scale structure and functionality of gluten protein and starch in re-steamed bread. Results showed that prolonged cold storage destroyed the integrity of gluten networks by breaking disulfide bonds and altering protein secondary structures, accompanied by moisture loss and migration; meanwhile, starch retrogradation was significantly promoted, resulting in increased hardness and decreased specific volume. The addition of 0.5–1.0% of matcha stabilized disulfide bonds and inhibited starch retrogradation, thus alleviating quality decline. When the addition amount exceeded 1.0%, high concentrations of polyphenols depolymerized gluten proteins and accelerated moisture transfer, causing a further drop in specific volume. Pearson correlation analysis verified the close correlations between macroscopic quality and microstructural characteristics. This study explored the mechanisms underlying the effects of cold storage time and matcha addition on the quality of re-steamed bread, providing a systematic scientific basis for the application of tea flour products in cold storage. 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

High-zinc blast furnace dust is a zinc-bearing solid waste generated during ironmaking. Efficient de-zincing and iron enrichment are required for its resource utilization. This study investigated the high-temperature reduction behavior and kinetic transition mechanism of cold-bonded briquettes made from high-zinc blast furnace dust with a small addition of iron ore powder, with particular emphasis on the effects of reduction temperature (1000–1200 °C) and holding time (10–60 min). The results show that reduction at 1200 °C for 60 min can effectively remove zinc and enrich iron. The de-zincing rate reached 92%, and the TFe grade increased to 50 wt.%, achieving the goal of efficiently removing zinc while improving the TFe grade of the reacted briquettes. During the middle and later stages of reduction (1100–1200 °C, 30–60 min), the content of newly formed metallic iron increased, which restored the briquette strength to 524 N after reduction. In addition, the reduction kinetics of the system evolved from interfacial chemical reaction control in the initial stage to three-dimensional internal diffusion control in the middle and later stages. These results provide a theoretical basis and technical reference for the resource utilization of high-zinc blast furnace dust. Full article

As a core nutritional component of milk, casein features excellent digestibility and biocompatibility, making it an ideal carrier for embedding natural bioactive substances in dairy product research. Luteolin, a typical flavonoid compound with superior antioxidant and anti-inflammatory bioactivities, is limited in industrial dairy applications due to poor environmental stability and low biological utilization. Moreover, the dynamic interplay mechanism between luteolin and casein throughout fermentation and cold storage remains unclear. This study hypothesized that luteolin could assemble with casein via non-covalent binding to form stable composite fermentation system, thereby optimizing the overall quality and functional attributes of fermented milk. This work aimed to explore the binding characteristics of luteolin of casein in fermented milk and its regulatory effects on products’ physicochemical properties, antioxidant capacity and nutritional digestibility. Experimental outcomes verified the hypothesis that luteolin bonded with casein through hydrogen bonding and hydrophobic interactions. With increased luteolin supplementation, the fermentation system presented lowered pH and elevated titratable acidity. Compared with control fermentation system without luteolin, the fermentatiuon system containing 0.06% luteolin achieved 31.31% higher DPPH radical scavenging rate, 27.02% higher ABTS clearance capacity, and 26.42% higher in vitro protein digestibility (p < 0.05). Dose-dependent increases in particle size and absolute zeta-potential enhanced system colloidal stability, while FTIR detection confirmed obvious variations in protein secondary structure in fermented milk. This study elucidates the distinctive structure–function correlation of the luteolin–casein fermentation system in fermented dairy matrices, providing original insights and reliable theoretical support for developing novel dairy products rich in functional nutritional factors. Full article

Permeable pavements are increasingly adopted to reduce urban runoff and support sustainable stormwater management; however, their long-term performance in cold regions is often limited by the need to maintain both hydraulic conductivity and durability under freeze–thaw cycles and de-icing salt exposure. This study investigates polyurethane (PU)-bound permeable composites based on granite aggregates for paver joint filling, permeable paver production, and monolithic permeable paving. This study provides a combined evaluation of aggregate gradation and PU binder content in relation to hydraulic performance, mechanical resistance, adhesion/cohesion, water absorption, and salt-freeze scaling resistance. Four mixtures were prepared using different combinations of 0/1 and 2/5 mm granite fractions and PU binder contents. The results showed that all mixtures exceeded the target permeability requirement of 2 × 10⁻⁵ m/s, while the coarse-only mixture with 3.0% PU binder provided the most balanced performance. This mixture achieved the highest permeability, the highest compressive and splitting tensile strength among the tested mixtures, the lowest water absorption, and the lowest surface scaling after 28 freeze–thaw cycles in 3% NaCl solution. The findings indicate that a coarse aggregate skeleton effectively bonded by the PU can support both rapid drainage and improved resistance to salt-freeze deterioration. However, further field validation under traffic loading, clogging, and long-term environmental exposure would be needed before full-scale application. Full article

3D-printed concrete (3DPC) enables formwork-free automated construction with geometric flexibility and improved material efficiency, yet its engineering reliability remains limited by interlayer weakening generated during sequential deposition. This review critically examines the formation, cross-scale consequences, and control of weak interlayer interfaces in 3DPC. In most studies, the 3DPC printing interval ranges from 20 s to 120 min, and the average interfacial bond strength ranges from 0.1 to 16 MPa. Interfacial weakness arises from the asynchronous evolution of adjacent layers in terms of contact quality, rheological recovery, moisture exchange, and early-age hydration. This mismatch promotes pore enrichment, discontinuity of hydration products, reduced phase continuity, and consequent local mechanical softening. These defects govern interlayer bonding, crack propagation, anisotropy, and stress-transfer pathways, and their effects propagate from material properties to member response, structural performance, and durability degradation. Rather than treating the interface as a localized cold joint, this review frames it as a process-induced multiscale variable linking printing history, microstructure, mechanical response, transport behavior, and serviceability. Current research remains constrained by non-comparable testing methods, undefined quantitative thresholds, and models that still rely heavily on empirical calibration. Future work should establish standardized characterization, transferable interface descriptors, multiscale predictive models, real-time quality control, and design methods that explicitly incorporate interfacial variability. Full article

Cold spray is a solid-state deposition technology with great potential for coating and repair applications. This study examines the compliance of the cold spray repair process with a qualification and testing framework based on the requirements set by the European Union Aviation Safety Agency (EASA). As part of this effort, the case study of a repair of a Main Landing Gear (MLG) aluminium component is investigated to demonstrate the applicability of the proposed framework. This framework integrates mechanical and microstructural evaluations, including bond strength, hardness profiling and microstructural characterisation according to relevant ASTM and ISO standards. Experimental results from post-repair testing indicated promising performance, while ongoing testing is aligning reasonably with expected benchmarks and showing compliance with the EASA requirements. Full article

The quality of interlayer bonding in roller-compacted concrete dam construction is significantly influenced by environmental factors, and traditional methods for determining initial and final setting are ill-suited for complex field conditions. Based on the Lower Kafue Hydropower Project in Zambia, a quality control method integrating maturity indicators and interlayer exposure time is proposed. Through designing and conducting field tests, roller-compacted concrete specimens were evaluated under varying exposure times (4–62 h) and interlayer treatment methods (cement slurry treatment, mortar treatment, no treatment, roughening, etc.). Based on a maturity calculation model, interlayer joints were classified into three categories—“hot joints,” “warm joints,” and “cold joints”—with corresponding evaluation criteria and treatment measures established. Experimental results indicate that shorter interlayer exposure time and lower maturity yield higher interlayer bond strength. Cement slurry treatment outperforms mortar treatment, while roughening further enhances bonding quality. A dynamic adjustment model based on monthly average temperatures effectively guides construction decisions under varying climatic conditions. Engineering applications demonstrate that this method enhances interlayer bonding quality and construction controllability, thereby ensuring the quality of interlayer pouring in roller-compacted concrete dams and improving the overall quality of such dams to meet design requirements. Full article

Acrylate hot-melt adhesives (AHMAs) are widely used in medical dressings, electronic components, and automotive interiors due to their solvent-free nature and high bonding strength. However, their wetting behavior on porous fabric substrates under varying coating temperatures—a critical factor for interfacial adhesion—remains poorly understood. To investigate how coating temperature affects the wetting and adhesion of acrylic hot-melt adhesives on fabric substrates, the apparent surface tension and viscosity of the adhesive (130–160 °C) and the apparent surface energy of the substrate (20–160 °C) were measured. By combining these measurements with contact angle decay curves on steel plates, scanning electron microscopy of cold-brittle cross-sections, and mechanical property tests, the study analysed the effects of temperature on wetting and spreading, penetration depth, and adhesive performance. Results show that with increasing temperature, adhesive surface tension and viscosity decrease, while fluidity improves; substrate surface energy shows no temperature dependence. The penetration depth into the fabric increases from 16 μm to 25 μm, and penetration uniformity gradually improves. However, both peel strength and loop tack continuously decrease with rising temperature, with optimal adhesion at 130 °C. A penetration depth model based on the Washburn equation effectively predicts the penetration behavior. Viscosity accounts for more than 50% of the effect, whilst the wetting factor contributes to a lesser extent. This study provides a theoretical basis for optimizing the coating process of acrylic hot-melt adhesives on fabric substrates. Full article

To investigate the bond performance between reinforcement and tunnel lining concrete under freeze–thaw cycles in plateau regions, pull-out tests were conducted on secondary-lining-reinforced concrete specimens subjected to different numbers of freeze–thaw cycles. The variations in the fundamental properties of the lining concrete, as well as the bond stress and maximum slip between the reinforcement and the concrete, were examined. The results indicate that, with an increasing number of freeze–thaw cycles, the mass of the lining concrete first increases and then decreases, while the compressive strength and splitting strength gradually decrease. The bond stress between the reinforcement and concrete shows a decreasing trend, whereas the maximum slip exhibits an increasing trend. Furthermore, a finite element model of the reinforced concrete pull-out specimen was established using ABAQUS software to simulate the bond performance under different freeze–thaw cycles. The comparison between experimental and simulated results validates the rationality of the finite element model. This study provides a reference for understanding the bond–slip behavior of tunnel lining reinforced concrete subjected to freeze–thaw environments in cold plateau regions. Full article

Freeze–thaw cycles are the main cause of subgrade damage in cold regions. To investigate how straw fibers affect the road performance of reinforced black soil in these areas, this study conducted unconfined compressive strength (UCS), California bearing ratio (CBR), and resilient modulus (RM) tests, supplemented by CT scanning. The novelty lies in comparing coarse and fine straw fibers and establishing a freeze–thaw damage prediction model. It analyzed the effects of straw fiber types (coarse and fine) and contents (0, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%) on the soil’s mechanical properties and reinforcement mechanisms. Results showed that straw fibers enhance soil mechanics by distributing stress, limiting soil particle movement, inhibiting crack growth, and reducing porosity. Fiber content impacts the mechanical properties of reinforced soil more significantly than fiber type. The optimal fiber content for both coarse and fine straw fibers is 1%. At this content, the UCS of coarse fiber-reinforced soil (CFS) reached 1.11 MPa, a 32.14% increase compared to the reference group (B-0), and the RM reached 207.39 MPa, a 63.70% increase compared to B-0. Meanwhile, the UCS of fine fiber-reinforced soil (FFS) reached 1.01 MPa, a 20.24% increase, and the RM reached 150.33 MPa, an 18.66% increase. Freeze–thaw cycles degrade mechanical properties by weakening the bond between soil and straw fibers. As the number of freeze–thaw cycles increases, both the UCS loss rate and RM loss rate rise. FFS exhibits superior freeze–thaw resistance compared to CFS, due to its lower porosity and fewer cracks. The developed freeze–thaw damage evolution equation shows a strong fit (R² > 0.85) and applies to straw fiber-reinforced black soil under the conditions of this study. This research provides a theoretical basis for designing eco-friendly straw fiber-reinforced subgrades in cold regions. Full article

To address poor interfacial compatibility between rubber powder and emulsified asphalt in cold-mixed asphalt mixtures, this study employed microwave activation to desulfurize and activate waste rubber powder. The investigation combined experimental research, molecular dynamics simulations, and solid–liquid separation methods to systematically explore the mechanism by which rubber powder activation influences cold-mixed emulsified asphalt systems. Results revealed an effective activation temperature of approximately 190 °C for rubber powder. The activation process, driven by microwave heating, involves main-chain scission and crosslink bond cleavage. Furthermore, moderate desulfurization reduces the solubility difference between rubber powder and asphalt, increases interfacial binding energy, and enhances the diffusion coefficient. Based on these findings, an optimal microwave activation scheme was proposed (4 min at 1040 W followed by 2 min at 873 W), which offers low energy consumption and excellent modification effects. Activation treatment reduces the initial viscosity by 33.9% and accelerates demulsification. Lastly, the results of molecular dynamics simulations are highly consistent with those of macroscopic experiments, forming a complete research chain of “microscopic mechanism analysis—macroscopic performance verification” and providing a theoretical basis and technical support for high-performance cold-mixed rubber-powder-modified emulsified asphalt mixtures. Full article

Under alkaline conditions, most commonly used preservatives exhibit limited efficacy and fail to meet the preservation requirements of coated tofu. This study aims to investigate the effects of metal-phenolic networks (MPNs) on quality deterioration, protein oxidation, conformation, and gel microstructure of coated tofu during cold storage (4 °C and 10 °C). The results showed that, compared with the untreated control group, MPNs treatment effectively inhibited protein oxidation, alleviated quality deterioration, delayed the degradation of color and texture, and reduced protein degradation, as evidenced by soluble protein contents that were 63.55% (4 °C) and 66.65% (10 °C) lower than those of the control group after 20 days of storage. MPNs treatment also improved the orderliness and stability of the protein secondary structure. In addition, electrophoretic analysis showed that MPNs markedly retarded the decline in band optical density of the 11S protein A subunit by 96.19% and 97.28% at 4 °C and 10 °C, respectively, and suppressed the increase in the B subunit by 13.28% and 73.20%, respectively. Moreover, MPNs treatment helped maintain a more compact gel network. Based on physicochemical characterization and Pearson correlation analysis, the preservative effect of MPNs on coated tofu under alkaline conditions was elucidated, revealing the internal correlation between the inhibition of quality deterioration and the regulation of protein oxidation. Specifically, MPNs mitigate protein disulfide bond loss, increase the β-sheet content, preserve the natural protein conformation and the relative proportion of 11S subunits, stabilize the gel microstructure, and thereby achieve quality preservation. These findings provide theoretical support and strategic reference for the development of preservation technologies for alkaline high-protein gel foods. Full article

The sustainable utilization of multiple reclaimed pavement materials is a critical pathway toward green highway construction. This study investigates the performance and synergistic mechanisms of cold-recycled mixtures incorporating both Reclaimed Asphalt Pavement (RAP) and Reclaimed Cement-Stabilized Base (RCSB), using emulsified asphalt as the primary binder. A comprehensive experimental program was conducted to evaluate the effects of reclaimed material proportions, mixing sequences, and curing ages on the mechanical strength, moisture susceptibility, and high-temperature stability of the mixtures. Microscopic characterization via Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopy (EDS) were employed to elucidate the Interfacial Transition Zone (ITZ) evolution. Results indicate that an optimal RCSB incorporation range of 20–40% establishes a robust “stone-to-stone” rigid skeleton, significantly enhancing the splitting strength (up to 0.87 MPa) and durability (Splitting Strength Ratio, TSR > 91%). SEM observations confirm the formation of a dense interpenetrating network structure within this range, where cement hydration products and asphalt films achieve optimal chemo-physical bonding. Exceeding 40% RCSB leads to a moisture-starved state and a sharp decline in dynamic stability due to insufficient binder coating. Micro-morphological characterization reveals that the transition from macro-interfacial debonding to a robust cohesive failure mode is the fundamental driver for the performance peak at 20–40% RCSB. SEM observations confirm the formation of a dense interpenetrating network structure, where cement hydration products successfully anchor into the asphalt film. This optimized ITZ effectively eliminates the stress concentration and aggregate crushing seen in high-RAP mixtures, thereby ensuring superior mechanical integrity. Furthermore, a pre-wetting mixing sequence ensures a high-energy mineral surface that promotes the heterogeneous nucleation of cement. SEM results show that this prevents the competitive adsorption between cement and asphalt, transforming the ITZ from a friable, loose state into a densified crystalline adhesive matrix. Full article

To solve the problems of poor weld formation, difficult slag removal, and inferior joint microstructure and hardness in conventional narrow-gap submerged arc welding (NG-SAW), a swing arc NG-SAW process assisted by pre-embedding cold wires was proposed. Synergistically optimizing the welding energy parameters and additional cold wires ensured sound weld formation and enhanced slag detachability, while the efficiency of multilayer welding was improved by reducing the number of weld layers by 33.3%. The slag adhesion mechanism is clarified as follows: a high welding heat input facilitates elemental diffusion at the weld–slag interface, leading to the formation of a continuous and thick interlayer composed of (Fe,Mn)O and MgO-Al₂O₃-CaO phases. This interlayer strengthens the chemical bonding between slag and weld, thereby impeding slag removal. Microstructure evolution analysis of the multilayer welded joint revealed that the variable-angle design increases the groove volume and, combined with the heat-absorbing effect of the additional wires, accelerates molten pool cooling, thereby refining grains in both the weld metal zone and reheat-affected zone. Meanwhile, the tempering exerted by the heat-affected zone (HAZ) of the subsequent weld layer on the previous layer is attenuated. This promotes the gradual transformation of hard-brittle lath martensite in the coarse-grained heat-affected zone (CGHAZ) of the bottom layer into tougher tempered martensite/bainite in the CGHAZ of the upper layers. As a result, the hardness uniformity within the HAZ, the critical weak region of the joint, was enhanced by 54%, enabling synchronous improvement in microstructural homogeneity, hardness distribution, and overall welding efficiency. Full article