Search Results (14,596)

In this study, a duplex treatment combining carburizing, nitriding, and subsequent induction hardening (IH) was applied to JIS-SCM420 low-alloy steel. A comprehensive evaluation was conducted to assess surface characteristics, including microstructure, hardness, residual stress, and fatigue performance. The IH process successfully produced a high-nitrogen-content ε-Fe_2-3(N,C) compound layer (2–3 μm thick) and fine acicular martensite at the surface, significantly enhancing surface hardness (950 HV0.03) and inducing beneficial compressive residual stress (−477 MPa). The IH-treated material exhibited a plane-bending fatigue strength of approximately 775 MPa, notably higher than that of conventionally carbonitrided specimens (700 MPa). This improvement was primarily attributed to the formation of the hard ε-Fe_2-3(N,C) compound layer and refined martensitic structure resulting from induction hardening. Additionally, IH activated residual interstitial elements, promoting the precipitation of stable surface nitrides. These microstructural changes effectively suppressed fatigue crack initiation and propagation, thereby extending fatigue life under cyclic loading conditions. Full article

Predictive maintenance (PdM) is a cornerstone of smart manufacturing, enabling the early detection of equipment degradation and reducing unplanned downtimes. This study proposes an advanced machine learning framework that integrates the Extreme Learning Machine (ELM) with a novel hybrid metaheuristic optimization algorithm, the Polar Lights Salp Cooperative Optimizer (PLSCO), to enhance predictive modeling in manufacturing processes. PLSCO combines the strengths of the Polar Light Optimizer (PLO), Competitive Swarm Optimization (CSO), and Salp Swarm Algorithm (SSA), utilizing a cooperative strategy that adaptively balances exploration and exploitation. In this mechanism, particles engage in a competitive division process, where winners intensify search via PLO and losers diversify using SSA, effectively avoiding local optima and premature convergence. The performance of PLSCO was validated on CEC2015 and CEC2020 benchmark functions, demonstrating superior convergence behavior and global search capabilities. When applied to a real-world predictive maintenance dataset, the ELM-PLSCO model achieved a high prediction accuracy of 95.4%, outperforming baseline and other optimization-assisted models. Feature importance analysis revealed that torque and tool wear are dominant indicators of machine failure, offering interpretable insights for condition monitoring. The proposed approach presents a robust, interpretable, and computationally efficient solution for predictive maintenance in intelligent manufacturing environments. Full article

In this study, glass fiber-reinforced polymer (GFRP) rebars were fabricated using epoxy resin matrix filled with 5 wt.% of hemp and bamboo powder fillers, both untreated and dielectric barrier discharge (DBD) plasma treated. The tensile, flexural, transverse shear, and pull-out bond strengths were evaluated to investigate the effects of filler type and surface modification. The results show that the incorporation of untreated fillers decreased tensile strength from 706.4 MPa for hemp to 682.3 MPa for bamboo. The plasma-treated hemp formulation demonstrated a higher recovery (762.1 MPa), approaching the control value (804.2 MPa). Transverse shear strength increased from 117.0 MPa (untreated hemp) to 128.3 MPa (plasma-treated hemp). The bond strength with concrete remained unaffected across all groups. Scanning electron microscopy (SEM) revealed improved filler dispersion, reduced voids, and enhanced resin wetting in the plasma-treated specimens. Fourier-transform infrared spectroscopy (FTIR) confirmed the introduction of polar functional groups such as hydroxyl and carbonyl groups onto the fiber surfaces following plasma exposure. These modifications contributed to improved interfacial adhesion and mechanical integrity. Overall, the DBD plasma treatment effectively enhanced the performance and interfacial characteristics of natural fiber-filled GFRP rebars, supporting their potential as sustainable reinforcements in structural applications. Full article

Background/Objectives: This study investigates specific neuropsychological functions—visuospatial working memory, attention, planning, and decision-making—among preschool-aged children with Developmental Coordination Disorder (DCD) compared to typically developing (TD) peers. The objective was to assess deficits in selective, sustained, and focused expressive attention, visuospatial and visual/verbal working memory, and decision-making abilities, and to examine their relationship with fundamental motor skills. Methods: A comparative study was conducted with Greek preschool-aged children using the Cognitive Assessment System (CAS) to evaluate cognitive processing (planning, attention, simultaneous processing) and the Movement Assessment Battery for Children—Second Edition (MABC-2) to assess motor skills. Results: Significant performance disparities were identified between DCD and TD children across attentional and planning domains, with notable cognitive–motor correlations. Discriminant function analyses revealed high classification accuracy (e.g., 73.9% for receptive attention, 79.5% for simultaneous processing), reinforcing the diagnostic value of targeted cognitive indices. Notably, approximately one-third of the children with DCD (17 out of 44) exhibited deficits in one or more cognitive domains. Conclusions: These findings highlight the importance of neuropsychological profiling in understanding DCD and suggest that targeted motor interventions may simultaneously enhance executive function. A strength-based, holistic assessment approach is recommended, supported by educator training and evidence-based therapeutic programming. Full article

This study investigates the strength and microstructural evolution of SRX-stabilized aeolian sand–gravel mixtures for flexible base applications in desert roads. CBR, UPS (uniaxial penetration strength), and compressive resilient modulus tests were conducted under varying SRX dosages (0.4–1.0%) and aeolian sand contents (30–50%). The results show that increasing the SRX dosage significantly improves all three indices, with the 0.5% SRX and 30% aeolian sand mixture yielding the CBR (385.89%) and UPS (0.938 MPa) and achieving a compressive resilient modulus that meets the requirements for graded aggregate base layers. XRD FTIR and SEM–EDS analyses reveal that the SRX enhances material structure primarily through physical mechanisms, forming dense films and bonding networks without inducing significant chemical reactions. Extended curing improves structural integrity, while excessive aeolian sand reduces compactness. SRX-stabilized aeolian sand gravel is a viable base and subbase material for desert highways. Full article

Borophene, a two-dimensional (2D) allotrope of boron, has emerged as a highly promising material owing to its exceptional mechanical strength, electronic conductivity, and diverse structural phases. Unlike graphene and other 2D materials, borophene exhibits inherent anisotropy, flexibility, and metallicity, offering unique opportunities for advanced nanotechnological applications. This review presents a comprehensive summary of recent progress in borophene synthesis methods, highlighting both bottom–up strategies such as chemical vapor deposition (CVD) and molecular beam epitaxy (MBE), and top–down approaches, including liquid-phase exfoliation and sonochemical techniques. A key challenge discussed is the stabilization of borophene’s polymorphs, as bulk boron’s non-layered structure complicates exfoliation. The influence of substrates and doping strategies on structural stability and phase control is also explored. Moreover, the intrinsic physicochemical properties of borophene, including its high flexibility, oxidation resistance, and anisotropic charge transport, were examined in relation to their implications for electronic, catalytic, and sensing devices. Particular attention was given to borophene’s performance in hydrogen storage and hydrogen evolution reactions (HERs), where functionalization with alkali and transition metals significantly enhances H₂ adsorption energy and storage capacity. Studies demonstrate that certain borophene–metal composites, such as Ti- or Li-decorated borophene, can achieve hydrogen storage capacities exceeding 10 wt.%, surpassing the U.S. Department of Energy targets for hydrogen storage materials. Despite these promising characteristics, large-scale synthesis, long-term stability, and integration into practical systems remain open challenges. This review identifies current research gaps and proposes future directions to facilitate the development of borophene-based energy solutions. The findings support borophene’s strong potential as a next-generation material for clean energy applications, particularly in hydrogen production and storage systems. Full article

Background: Creatine supplementation is widely used to enhance exercise performance, mainly resistance training adaptations, yet its differential effects on upper- and lower-body strength and muscular power remain unclear across populations. Objective: This systematic review and meta-analysis aimed to quantify the effects of creatine supplementation in studies that included different exercise modalities or no exercise on upper- and lower-body muscular strength and power in adults. Methods: A comprehensive search of PubMed, Scopus, and Web of Science was conducted through 21 September 2024 to identify randomized controlled trials evaluating the effects of creatine supplementation on strength (bench/chest press, leg press, and handgrip) and power (upper and lower body). Weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated using random-effects modeling. Subgroup analyses examined the influence of age, sex, training status, dose, duration, and training frequency. Results: A total of 69 studies with 1937 participants were included for analysis. Creatine plus resistance training produced small but statistically significant improvements in bench and chest press strength [WMD = 1.43 kg, p = 0.002], squat strength [WMD = 5.64 kg, p = 0.001], vertical jump [WMD = 1.48 cm, p = 0.01], and Wingate peak power [WMD = 47.81 Watts, p = 0.004] when compared to the placebo. Additionally, creatine supplementation combined with exercise training revealed no significant differences in handgrip strength [WMD = 4.26 kg, p = 0.10] and leg press strength [WMD = 3.129 kg, p = 0.11], when compared with the placebo. Furthermore, subgroup analysis based on age revealed significant increases in bench and chest press [WMD = 1.81 kg, p = 0.002], leg press [WMD = 8.30 kg, p = 0.004], and squat strength [WMD = 6.46 kg, p = 0.001] for younger adults but not for older adults. Subgroup analyses by sex revealed significant increases in leg press strength [WMD = 9.79 kg, p = 0.001], squat strength [WMD = 6.43 kg, p = 0.001], vertical jump [WMD = 1.52 cm, p = 0.04], and Wingate peak power [WMD = 55.31 Watts, p = 0.001] in males, but this was not observed in females. Conclusions: This meta-analysis indicates that creatine supplementation, especially when combined with resistance training, significantly improves strength in key compound lifts such as the bench or chest press and squat, as well as muscular power, but effects are not uniform across all measures. Benefits were most consistent in younger adults and males, while older adults and females showed smaller or non-significant changes in several outcomes. No overall improvement was observed for handgrip strength or leg press strength, suggesting that the ergogenic effects may be more pronounced in certain multi-joint compound exercises like the squat and bench press. Although the leg press is also a multi-joint exercise, results for this measure were mixed in our analysis, which may reflect differences in study design, participant characteristics, or variability in testing protocols. The sensitivity of strength tests to detect changes appears to vary, with smaller or more isolated measures showing less responsiveness. More well-powered trials in underrepresented groups, particularly women and older adults, are needed to clarify population-specific responses. Full article

To enhance both the environmental performance and mechanical properties of phosphate solid waste backfill materials, this study examines the effects of corn straw fibre (CS), rice straw fibre (RS), and jute fibre (JF), each at five lengths (3–15 mm) and five dosages (0.1–0.5 wt%), on the rheological behaviour, mechanical strength, and microstructural characteristics of the backfill slurry. The experimental results showed that the incorporation of natural fibres markedly improved both the compressive and tensile strengths of backfill materials. For example, incorporating CS at a length of 12 mm and a dosage of 0.2 wt% increased the compressive and tensile strengths by 144.4% and 18.8%, respectively. Likewise, RS at 3 mm and 0.2 wt% increased the strengths by 68.3% and 11.9%, while JF at 12 mm and 0.5 wt% enhanced them by 108.2% and 14.9%, respectively. Ion leaching experiments and XPS analyses confirmed that the incorporation of natural fibres effectively adsorbed and immobilized phosphorus and fluorine in phosphogypsum. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses revealed that the improved mechanical strength was primarily attributed to fibre-bridging effects and enhanced fibre–matrix bonding. Furthermore, nuclear magnetic resonance (NMR) analysis demonstrated that incorporating natural fibres reduced the porosity of backfill materials (from 12.9% to 8.14%) while increasing their density. This study provides an experimental foundation for optimizing backfill materials and recommends a 12 mm CS fibre length at a dosage of 0.2 wt% to improve the stability and safety of mine fill structures. Full article

The precise measuring and control of fiber tension are critically important for enhancing structural and mechanical properties in spinning processes, as tension directly influences orientation, crystallinity, and mechanical properties. However, current tension measurement methods primarily operate offline and lack real-time measuring capabilities. A non-contact fiber tension detection system is introduced to investigate the effects of draw tension and its uniformity on the structure and mechanical properties of polyester fibers. During experiments conducted at a spinning speed of 1200 m/min across different draw ratios, the non-contact system demonstrated strong agreement with the contact tension detector. The results showed that increasing the tension from 34 cN to 164 cN reduced the monofilament diameter from 39.61 µm to 20.35 µm. Simultaneously, the orientation factor nearly tripled, while crystallinity increased from 55.72% to 77.39%. Mechanical testing revealed a 50.96% improvement in breaking strength, rising from 1.57 to 2.37 cN/dtex, accompanied by a significant decrease in elongation at break from 275.55% to 34.95%. However, tension fluctuations, characterized by an average fluctuation coefficient increase from 4.51% to 18.18%, caused diameter inconsistency. These fluctuations also reduced the orientation factor by 10.78%, lowered crystallinity, and substantially deteriorated mechanical properties. These findings underscore the critical importance of real-time, online tension monitoring for ensuring polyester fiber quality and performance during production. Full article

To address the brittle matrix failure frequently observed in filament-wound composite layers of onboard pressure vessels operating under cryogenic and high-pressure conditions, we studied a bisphenol-A epoxy resin (DGEBA) system modified with polyetheramine (T5000) and 3,4-Epoxycyclohexylmethyl 3′,4′-epoxycyclohexanecarboxylate (CY179). The curing and rheological behavior of the modified resin were first evaluated, revealing a favorable processing, with viscosity suitable for wet-filament winding. Subsequently, its coefficient of thermal expansion (CTE) and tensile properties were characterized over the 300 K–90 K range, demonstrating a linear increase in elastic modulus and tensile strength with decreasing temperature. Carbon fibre-reinforced polymer composites (CFRP) were then fabricated using this resin system, and both longitudinal and transverse tensile tests, along with microscopic fracture surface analyses, were conducted. The results showed that CFRP-0° specimens exhibited an initial increase followed by a decrease in elastic modulus with decreasing temperature, whereas CFRP-90° specimens demonstrated pronounced cryogenic strengthening, with tensile strength and modulus enhanced by 52.2% and 82.4%, respectively. The findings provide comprehensive properties for the studied resin system and its CFRP under room temperature (RT) to cryogenic conditions, offering a basis for the design and engineering of cryo-compressed hydrogen storage vessels. Full article

To meet the requirements of a prefabricated building with specific strength limitations and assembly rate criteria, the research proposes a Low-Strength Foamed Concrete Cold-Formed Steel (CFS) Framing Composite Enclosure Wall Panel (LFSW). The ABAQUS 2024 finite element analysis (FEA) combined with bending performance tests on five specimens were employed to examine crack propagation and failure modes of wall panels under wind load, investigating the influence mechanisms of foamed concrete strength, CFS framing wall thickness, CFS framing section height, and concrete cover thickness on the flexural performance of wall panels. The experimental results demonstrate that increasing the steel thickness from 1.8 mm to 2.5 mm enhances the ultimate load-carrying capacity by 46.15%, while enlarging the section height from 80 mm to 100 mm improves capacity by 26.67%. When the foamed concrete strength increased from 0.5 MPa to 1.0 MPa, the wall panel cracking load increased by 50%, while the ultimate load capacity changed by less than 5%. Increasing the concrete cover thickness from 25 mm to 35 mm enhanced the ultimate capacity by 7%, indicating that both parameters exert limited influence on the composite wall panel’s flexural capacity. Finite element simulations demonstrate excellent agreement with experimental results, confirming effective composite action between foamed concrete and CFS framing under service conditions. This validation establishes that the simplified analytical model neglecting interface slip provides better accuracy for engineering design, offering theoretical foundations and practical references for optimizing prefabricated building envelope systems. Full article

With rapid industrialization, large quantities of industrial solid waste are generated annually. In Panzhihua, China, approximately 300,000 tons of limestone mine dust filter residue (LMDFR) is produced. This study investigates the properties of LMDFR and its potential as a supplementary cementitious material. LMDFR was blended with fly ash (FA) to replace 30% of cement in mortar. Tests were conducted to measure the mortar’s flowability and its compressive and flexural strengths after 7 and 28 days of curing, and XRD, SEM, TG, and DSC analyses were conducted on 28-day specimens. LMDFR primarily comprises ≥95% CaCO₃, with a specific surface area of ~1.3 m²/g and density of 2.694 g/cm³. Mortar flowability increased with LMDFR content, reaching 112.83% when used alone. Flexural strength was largely unaffected, while the 7-day compressive strength significantly improved. However, the 28-day strength decreased when LMDFR was used alone, with a 28-day activity index of 61.10%, compared with 71.52% for FA. A 1:1 blend of LMDFR and FA improved the activity index to 83.18%. Microstructural and thermal results corroborated strength and flowability trends. In conclusion, LMDFR demonstrates promising potential as a supplementary cementitious material in concrete applications. When blended with fly ash at a 1:1 ratio, the composite admixture significantly enhances flowability and early compressive strength while maintaining adequate long-term performance. This synergistic combination not only improves the physical properties of cement mortar but also provides a sustainable solution for the large-scale utilization of industrial solid waste. Full article

Traditional information distillation networks using single-scale convolution and simple feature fusion often result in insufficient information extraction and ineffective restoration of high-frequency details. To address this problem, we propose a lightweight image super-resolution reconstruction network based on multi-order information optimization. The core of this network lies in the enhancement and refinement of high-frequency information. Our method operates through two main stages to fully exploit the high-frequency features in images while eliminating redundant information, thereby enhancing the network’s detail restoration capability. In the high-frequency information enhancement stage, we design a self-calibration high-frequency information enhancement block. This block generates calibration weights through self-calibration branches to modulate the response strength of each pixel. It then selectively enhances critical high-frequency information. Additionally, we combine an auxiliary branch and a chunked space optimization strategy to extract local details and adaptively reinforce high-frequency features. In the high-frequency information refinement stage, we propose a multi-scale high-frequency information refinement block. First, multi-scale information is captured through multiplicity sampling to enrich the feature hierarchy. Second, the high-frequency information is further refined using a multi-branch structure incorporating wavelet convolution and band convolution, enabling the extraction of diverse detailed features. Experimental results demonstrate that our network achieves an optimal balance between complexity and performance, outperforming popular lightweight networks in both quantitative metrics and visual quality. Full article

Mechanised agricultural operations are often performed individually, under minimal supervision and across a wide range of unfavourable working conditions, resulting in a complex mixture of hazards and external stressors that severely affect safety conditions. Socio-technical and environmental constraints significantly affect safety culture and require continuous performance adjustments to overcome timing pressures, resource limitations, and unstable weather conditions. This study introduces a FRAM-based safety culture model that embeds the thoroughness-efficiency trade-off (ETTO) in four distinct operational modes that adhere to specific safety cultures, namely, thoroughness, risk awareness, compliance, and efficiency. This model has been instantiated for mechanised ploughing: foreground task functions were coupled with background functions that represent socio-technical constraints and environmental variability, while severity classes for potential incidents were derived from the US OSHA accident database. The framework was also supported by a semi-quantitative Resonance Index based on severity and coupling strength, the Total Resonance Index (TRI), to assess how variability propagates in foreground functions and to identify hot-spot functions where small adjustments can escalate into high resonance and hazardous conditions. Results showed that the negative effects on functional resonance generated by safety detriment on TRI observed between compliance and effective working modes were three times larger than the drift between risk awareness and compliance, demonstrating that efficiency comes with a much higher cost than keeping safety at compliance levels. Extending the proposed approach with quantitative assessments could further support the management of socio-technical and environmental drivers in mechanised farming, strengthening the role of safety as a competitive asset for enhancing resilience and service quality. Full article

Polyetherimide (PEI)/molecular semiconductor-based all-organic dielectric composites have garnered significant attention due to their exceptional energy storage performance at elevated temperatures. In this work, the high-electron-affinity semiconductor 5,6,12,13-tetrachloro-2,9-bis(2-ethylhexyl)anthra[2,1,9-def:6,5,10-d′e′f]diisoquinoline-1,3,8,10(2H,9H)-tetraone (TCEHAQ) is employed as a filler to enhance the dielectric energy storage performance of PEI. It is believed that TCEHAQ can immobilize electrons and reduce charge transport in dielectric composites. The results demonstrate that the breakdown strength of PEI with only 0.5 wt% of TCEHAQ increased from 450 MV/m to 600 MV/m at room temperature, while the maximum discharge energy density (U_d) reached 5.99 J/cm³, and the discharge efficiency (η) was 96.5%. Meanwhile, the breakdown strength of the 0.5 wt% TCEHAQ/PEI blend at 150 °C was 500 MV/m, and the maximum U_d and η were 3.68 J/cm³ and 81.0%, respectively. This is a straightforward and effective method for fabricating large-area, high-quality dielectric energy storage films suitable for use in harsh environments. Full article