Search Results (63,050)

Optimizing the parameters of the manufacturing process for products in terms of metalworking equipment is one of the key tasks in technological preparation for production. This process is structurally complex, characterized by an ordered set of actions of various types. The basis for improving the efficiency of the technological process is the comprehensive optimization of the parameters of individual elements that form its structure. To solve this problem, an integrated model for comprehensive multi-criteria optimization of a structurally complex process has been developed, establishing a clear hierarchical relationship between its elements. The model is based on the structural decomposition of two processes: the process of forming individual design elements and the technological process of manufacturing a product. Structural hierarchical models have been developed for each process. The structure of the integrated model contains six levels of control. For each level of control, a set of target indicators and control parameters has been formed. The article presents the results of testing the proposed model using the example of optimizing the technological process of mechanical processing for the “Housing” product. As part of the study, structural and parametric optimization of the manufacturing process for this part was carried out. During the study, the structure of the technological processing route was optimized, as well as individual technological operations and technological transitions. Over the course of the work, the technological equipment and processing methods used for shaping a number of surfaces were replaced. As a result of the optimization, the overall labor intensity of the technological process for manufacturing the “Housing” product was reduced by 19.8%, and the manufacturing accuracy of the most critical surfaces was increased by 16.4%. The results confirm the effectiveness of the proposed model for comprehensive optimization of the mechanical processing technological process. Full article

Global poultry production continues to expand rapidly to meet the growing demand for affordable and high-quality animal protein. However, this growth raises pressing concerns about environmental sustainability, natural resource use, and public health. Although current initiatives, such as improved housing systems, optimized feeding practices, and partial soybean meal substitution, have helped mitigate some impacts, comprehensive integrated solutions remain underexplored. This review synthesizes emerging nutritional and management innovations that enhance the sustainability of poultry production while maintaining profitability. It addresses three central research questions: (1) Which alternative feed ingredients most effectively preserve animal performance while minimizing environmental burdens? (2) How can environmental management practices enhance resource efficiency and waste valorization? (3) What roles do life cycle assessment methodologies and policy frameworks play in advancing sustainable poultry systems? Evidence from 100 peer-reviewed studies, industrial data, and field analyses reveals that incorporating insect meals, algae, and agro-industrial by-products can reduce dependence on soybean meal by 20–40% and improve feed efficiency by 5–12% across various poultry production systems. Furthermore, integrating environmental management strategies, such as manure valorization, efficient water and energy use, and the adoption of renewable energy, substantially reduces greenhouse gas emissions and promotes circular economic principles. Life cycle assessment studies confirm that combined dietary and management interventions yield greater reductions in carbon footprint than isolated measures. Future research should focus on optimizing interactions among feed strategies, environmental management, and policy frameworks through digital technologies, nanomaterial-based feed additives, and region-specific sustainability plans to accelerate the transition toward resilient, climate-smart poultry production systems. Full article

Hybrid renewable energy systems (HRES) combining photovoltaic, wind, fuel cell, and energy storage technologies are becoming established as viable options for reliable, environmentally friendly distributed electricity generation. In this review, we examine the key architectures, monitoring and forecast approaches, and control systems that improve the efficiency of HRES and facilitate the just-energy transition to low-carbon power generation systems. The main optimization and decision-aware approaches, particularly the evolutionary generation algorithms and machine learning-based prediction models, are addressed with a focus on improving energy allocation, cost minimization, and increased use of clean renewable energy sources. Technical, economic, and environmental performance indicators, such as the levelized cost of energy (LCOE), net present cost (NPC), renewable fraction (RF), and CO₂ emissions reduction, have been compared to demonstrate the feasibility of various system scenarios. This paper evaluates and summarizes recent case studies from around the world and presents the best practices and the challenges they encounter, including resource availability, governance, and economic drivers. The balance of the paper demonstrates that smart forecasting with advanced energy management approaches is crucial for developing sustainable and resilient hybrid distributed power systems for the future. Full article

Excavation adjacent to operating urban rail transit faces formidable deformation control challenges. To address this, a parametric collaborative optimization framework integrating micro steel pipe pile isolation and temporary intermediate partition wall reinforcement is proposed. Taking a foundation pit project at Shangdi Station of Beijing Metro Line 13 as a case study, a three-dimensional finite element model was established using the Hardening Soil constitutive model and calibrated with field monitoring data. Optimization analysis reveals that micro-pile spacing is the dominant factor controlling local rail settlement, while intermediate partition wall thickness primarily dictates global surface settlement. By balancing stringent safety limits with construction economy through a multi-objective evaluation, the preferred support configuration was calculated to be 273 mm diameter micro-piles at 500 mm spacing, combined with a 300 mm-thick partition wall. This collaborative configuration successfully truncates lateral soil displacement, reducing maximum rail settlement by over 55% and surface settlement by 53.6% compared to the baseline. Field monitoring results show high consistency with the numerical predictions (RMSE = 0.1438 mm), confirming the reliability of the proposed parametric collaborative optimization framework. Ultimately, this framework provides a validated, quantitative design methodology and a practical reference for support design in constrained excavations adjacent to existing sensitive infrastructure. Full article

Green finance seeks to reconcile economic expansion with environmental protection and may, by relaxing financing constraints on clean-energy projects, contribute to lower energy poverty. Using provincial panel data from China over 2010–2019, this study examines the relationship between green finance development and energy poverty and evaluates potential spatial spillovers. The results show that green finance development is negatively associated with energy poverty, and this relationship remains statistically robust in dynamic-panel specifications estimated using system generalized method of moments (system GMM). Mechanism analyses further provide suggestive evidence that this negative association may operate partly through greater energy-supply investment and improved energy-infrastructure conditions. Spatial econometric evidence also indicates the presence of spillover effects: improvements in green finance in one province are associated with lower energy poverty in neighboring provinces. These findings imply that efforts to eradicate energy poverty should explicitly incorporate green finance, recognize regional heterogeneity in green finance development, and improve the transmission of green finance into tangible investment in clean energy and energy infrastructure. Interprovincial policy coordination is also warranted given spatial interdependence. Full article

Advanced thermal management applications, including electronics cooling, battery systems, and micro heat exchangers, are increasingly requiring thermally conductive yet flexible polymer composites. Composite films containing total nanofiller loadings of 2.5, 5, 7.5, and 10 wt.% were systematically characterized using SEM, TGA, DSC, TT, and SSTM following ASTM C177-19. SEM analysis confirmed uniform dispersion and effective network formation of MWCNTs and GNPs within the TPU matrix at higher filler loadings. Thermal stability improved significantly, with the degradation onset temperature increasing from 319.2 °C for pure TPU to 369 °C for the TPU/MWCNT/GNP (90/5/5 wt.%) composite. DSC results revealed enhanced glass transition and melting temperatures, indicating improved thermal resistance and crystallinity. Mechanical testing showed a substantial increase in Young’s modulus, reaching 72.5 MPa for the 90/5/5 wt.% composite, corresponding to a 286.66% improvement over pure TPU. Most notably, steady-state thermal conductivity increased dramatically from 0.20 W/mK for pure TPU to 1.533 W/mK for the 90/5/5 wt.% composite, representing a 666.50% enhancement. The experimental results closely aligned with percolation-based theoretical models at higher filler concentrations. Overall, the developed hybrid nanofiller TPU composites demonstrate a synergistic improvement in thermal conductivity, mechanical strength, and thermal stability, making them promising candidates for flexible thermal management components in electronics, automotive, renewable energy, and biomedical applications. Full article

The theory of physical degrees of freedom (DoF) developed by Franceschetti–Migliore–Minero (FMM) establishes a fundamental phase transition in the singular-value spectrum of electromagnetic radiation operators under maximal rotational symmetry. In this work, we revisit this result from a symmetry-explicit operator-theoretic perspective and extend it to scenarios with reduced and controllable symmetries, with particular emphasis on reconfigurable intelligent surfaces (RISs). We model the radiation process as a compact operator acting between admissible source and observation spaces and characterize its symmetry through group equivariance. This formulation enables a systematic decomposition of the operator into irreducible representation sectors associated with the effective symmetry group, defined as the intersection of symmetries supported jointly by the source architecture, RIS geometry and programmability, receiver configuration, and propagation environment. We show that the FMM phase transition persists within each symmetry sector and that the total DoF budget is redistributed across sectors according to symmetry constraints. A key outcome of this analysis is the distinction between physical and effective degrees of freedom. While breaking the maximal $\mathrm{SO}\left(2\right)$ symmetry does not increase the total number of electromagnetic DoF dictated by physics, symmetry reduction modifies their allocation across sectors, potentially lifting degeneracies and increasing the number of degrees of freedom that can be effectively addressed by a given excitation, RIS control, and measurement architecture, even when the total number of physical DoF remains fixed by fundamental limits. This clarifies the role of controlled symmetry breaking as a design mechanism rather than a means to surpass fundamental limits. The proposed framework bridges electromagnetic operator theory, representation theory, and RIS-enabled system design, providing both rigorous symmetry-resolved DoF accounting and actionable insights for excitation, surface programmability, and measurement strategies under practical architectural constraints. Full article

As the world’s largest carbon emitter and one of the countries facing severe air pollution challenges, China is under growing pressure to promote coordinated carbon reduction and air pollution control in support of sustainable development. From the perspective of interprovincial trade-embedded emissions, this study examines the spatiotemporal evolution, regional heterogeneity, and driving mechanisms of the synergy between embodied carbon emissions and air pollution emissions across 30 provincial-level regions in China in the 2012–2017 period. The multi-regional input–output (MRIO) model and coupling coordination degree (CCD) model are used to measure embodied emissions and the synergy effect, while the stochastic impacts by regression on population, affluence, and technology (STIRPAT) and geographically and temporally weighted regression (GTWR) models are employed to identify the main driving factors and their spatiotemporal heterogeneity. The results show that the overall synergy index of embodied carbon and air pollution emissions in China showed an increasing trend, and provinces with high-quality coordination shifted southward. Low-carbon policy and technology development mainly acted as positive drivers, whereas air pollution reduction policy and energy intensity tended to exert inhibitory effects; the role of energy consumption was more conditional and stage-specific. These findings provide useful evidence for differentiated governance, coordinated air pollution and carbon reduction, and the green and low-carbon transition. Full article

Financial development is widely regarded as an important factor influencing renewable energy consumption. Nevertheless, empirical studies conducted by various scholars have revealed that the effect of financial development on renewable energy consumption remains controversial. Based on this backdrop, this paper endeavors to analyze the nonlinear influence of financial development on renewable energy consumption from the perspective of moderating effects. First of all, this paper theoretically analyzes the potential moderating effects of financial development itself, urbanization, and environmental regulation on the impact of financial development on renewable energy consumption. Subsequently, leveraging the Panel Smooth Transition Regression (PSTR) model and the global panel data of 143 countries from 1996 to 2020, the empirical tests are conducted to verify these moderating effects. The results indicate that the variations in moderating variables can lead to disparities in the influence of financial development on renewable energy consumption. Specifically, with the increase in financial development level, urbanization rate, and environmental regulation intensity, the promoting effect of financial development on renewable energy consumption gradually strengthens. Finally, based on the aforementioned research findings, this paper proposes corresponding policy recommendations from the perspectives of these moderating factors. Full article

This study integrates physical similarity experiments with numerical simulations to examine how overburden lithology influences roof caving behavior and stress field evolution at a longwall mining face. The results demonstrate that overburden strength significantly governs the timing, extent, and periodicity of roof caving, while also strongly affecting the evolution of mining-induced stress. As lithological strength increases, both damage and displacement within the overburden strata decrease. High-strength roofs exhibit larger caving step distances and longer stress accumulation periods. In contrast, low-strength roofs enter the plastic deformation stage earlier, leading to shorter caving step distances, more frequent caving events, and a wider caving range. During coal seam extraction, roof deformation is accompanied by stress concentration and release, which are processes that are closely associated with dynamic disasters. Due to their higher elastic modulus and compressive strength, high-strength rock strata can accumulate greater elastic strain energy prior to failure. Once instability occurs, the rapid release of stored energy leads to intense stress redistribution and dynamic loading. As lithological strength increases, the stress concentration shell evolves from an arch-shaped structure to a flatter configuration. This transition results in higher internal stress levels and stronger stress concentration, thereby increasing the risk of dynamic disasters such as impact instability. Therefore, maintaining the stability of the stress concentration shell and preventing its migration into deeper strata are essential for ensuring surrounding rock stability and safe mining operations. Full article

Background and Objectives: Rates of obesity have been consistently increasing in recent years across all age groups, with a notable rise among young people. Obesity represents a persistent inflammatory condition and a key contributor to various chronic health problems, such as cardiovascular disorders, metabolic abnormalities, cancer, and psychological conditions. The move from high school to university is a transitional phase accompanied by specific pressures that can affect both body weight control and mental health in students. This cross-sectional investigation aimed to investigate potential associations between excess weight and the presence of depressive and anxiety symptoms in university populations. Methods: This cross-sectional analysis included 5298 students enrolled at universities across ten geographic areas of Greece. Participants filled out questionnaires concerning demographic information and lifestyle behaviors. Levels of depression and anxiety were measured using the Beck Depression Inventory (BDI-II) and the short form of the State Anxiety Inventory (STAI-6), respectively. Measurements of height and body weight were obtained to compute Body Mass Index (BMI). Results: The presence of overweight or obesity among students was significantly and independently related to female sex, urban residence, living independently, tobacco use, and lower academic performance (p = 0.0103, p = 0.0102, p = 0.0203, p = 0.0075, and p = 0.0168, respectively). Individuals reporting insufficient physical activity had 85% higher odds of being overweight or obese (p = 0.0068). Similarly, participants experiencing depressive or anxious symptomatology had more than double odds of excess body weight compared with those without such symptoms (p = 0.0015 and p = 0.0012, respectively). Furthermore, poor Mediterranean diet adherence was linked to more than a twofold increase in the odds of overweight or obesity (p = 0.0005). Conclusions: These findings offer considerable evidence that symptoms of depression and anxiety may serve as significant contributors to the development of overweight and obesity among university students. Additional longitudinal studies are strongly encouraged to substantiate these observations. Full article

Nuclear energy has emerged as a crucial technological solution for ensuring energy security and achieving carbon neutrality goals, given its ultra-high energy density and near-zero carbon emissions against the backdrop of rapid socioeconomic development, increasing energy demands, and accelerated global transition toward low-carbon energy structures. As the core component for energy conversion in nuclear reactors, fuel elements critically determine reactor efficiency and safety performance, with the fission product retention capability of silicon carbide layers in multilayer-coated fuel particles having been thoroughly validated through high-temperature gas-cooled reactor irradiation tests. The precise sphericity control of large-sized UO₂ fuel kernels represents a fundamental requirement for enhancing tristructural isotropic (TRISO) fuel particle performance and advancing Generation IV nuclear power plant development. This study presents a sphericity control strategy based on sol–gel processing that synergistically integrates physicochemical regulation of gelling media with multi-field washing flow field optimization. By implementing silicone oil-mediated interfacial tension gradient control, we effectively suppressed gel sphere destabilization while developing an innovative three-phase sequential washing technique involving kerosene washing, anhydrous ethanol interfacial transition, and ammonia solution replacement, which significantly enhanced mass transfer diffusion in stagnant liquid films and revolutionized fuel microsphere washing technology with improved efficiency and quality. Experimental results demonstrate that this integrated approach increases kernel sphericity qualification to 99.8%, reduces washing solution consumption by 79%, and achieves an average sphericity of 1.03. The research establishes a coupling mechanism between gelling media and multi-field washing processes, elucidating the synergistic effect between interfacial tension regulation and washing optimization, thereby providing both theoretical foundations and engineering application basis for the precision manufacturing of high-performance nuclear fuels. Full article

Background: This case report presents a 12-year-old male with vertically transmitted chronic hepatitis B virus (HBV) infection, exhibiting a rare pan-reactive serological profile (concurrent HBsAg, HBsAb, HBeAg, HBeAb, and HBcAb positivity) alongside fluctuating low-level viremia (HBV DNA: 1.06 × 10² IU/mL to undetectable). Rigorous exclusion of technical artifacts confirmed the authenticity of this atypical serologic pattern, observed in <0.001% of the general population. Methods: Liver biopsy and immunohistochemical staining were performed to evaluate hepatic inflammation and fibrosis. HBV serological markers and viral load were quantified using commercial diagnostic kits, with longitudinal monitoring for 18 months. Results: Liver biopsy revealed Grade 2 inflammation with focal HBsAg/HBcAg expression, supporting immune-active chronic hepatitis B (CHB) despite partial seroconversion. The patient’s clinical course highlights key challenges in pediatric HBV management: (1) delayed immune reconstitution (18-month longitudinal HBeAg/HBeAb dynamics), (2) non-linear virologic-ALT correlation, and (3) diagnostic ambiguity in pan-positive serology—potentially reflecting S-gene escape mutants or transitional immune responses. Initiation of tenofovir disoproxil fumarate (TDF) achieved sustained virologic suppression, underscoring the importance of early antiviral therapy in pediatric CHB with atypical markers. Conclusions: This case provides preliminary insights into the complex interplay between viral evolution and immature host immunity, advocating for refined monitoring protocols integrating high-sensitivity HBV DNA, quantitative serology, and non-invasive fibrosis assessment in pediatric HBV care. Full article

Deep coalbed methane (CBM) reservoirs are characterized by high in situ stress, and the effective stress during CBM production is significant, leading to substantial damage to reservoir permeability. Studying the variation patterns of coal permeability during stress unloading is crucial for revealing the mechanisms by which CBM stimulation through slotting and cavity creation modifies in situ stress. To understand the permeability variations in fractured coal under stress changes, gas seepage experiments were conducted using seven deep coal samples obtained from the Linxing–Shenfu mining area in the Ordos Basin of North China. Through these experiments, permeability variations in coal under different confining, axial, and gas pressures were investigated, and their implications for permeability enhancement through hydraulic slotting in deep coal seams were analyzed. The results show that during loading, permeability decreases with increasing effective stress, and the rate of permeability damage increases. During unloading, the changes in coal permeability transition from slow to rapid, with the stress sensitivity coefficient increasing and the stress sensitivity becoming more pronounced. Regardless of the loading or unloading process, lower axial pressure leads to higher permeability, greater permeability recovery and damage rate, a larger stress sensitivity coefficient, and stronger stress sensitivity of the coal. For every 4 MPa decrease in the axial pressure, the permeability increases by approximately 0–10%, and the permeability recovery rate increases by about 6%. This is because the lower axial pressure reduces the effective stress acting on the coal matrix and fractures, thereby widening the flow channels and enhancing both the permeability and its recovery capacity. In addition, for every 0.3 MPa increase in the gas pressure, the permeability increases by approximately 10–50%, and the permeability recovery rate increases by about 20%. This indicates that elevating pore pressure effectively counteracts effective stress, expands fracture apertures, and promotes fracture connectivity. This work demonstrates that fractured coal is highly sensitive to stress and that stress relief plays a crucial role in enhancing the permeability of deep coal seams. Full article

Objectives: To investigate the effects of Roxadustat and recombinant human erythropoietin (rHuEPO) on glycemic control and glycated hemoglobin (HbA1c) in non-dialysis type 2 diabetic kidney disease (DKD) patients with anemia. Methods: This retrospective study enrolled 449 patients, who were divided into three groups—the rHuEPO group (n = 252), the Roxadustat group (n = 102), and the switch group (n = 95)—in which patients were converted from rHuEPO to Roxadustat. All treatments lasted for more than three months. Changes in HbA1c and other indicators within groups as well as differences among groups were evaluated. Results: In the rHuEPO group, HbA1c levels decreased from 7.08 ± 1.19 to 6.41 ± 0.60 (p < 0.001), and they returned to baseline levels by 6–12 months (p > 0.05). In the Roxadustat group, HbA1c fluctuated but none of the differences reached statistical significance (p > 0.05). In the switch group, HbA1c decreased during rHuEPO treatment (p < 0.05) and returned to baseline after switching to Roxadustat (p > 0.05). No significant changes in blood glucose levels were observed in any group after treatment (p > 0.05). Multivariate linear regression analysis showed that changes in iron metabolism parameters, erythrocyte parameters, inflammatory markers, and glucose-lowering or lipid-lowering regimens had no significant effect on the change in HbA1c in the Roxadustat group (F = 0.834, p = 0.620), while the multivariate model of rHuEPO group also lacked statistical significance (F = 1.142, p = 0.170). After treatment, all three groups showed improvements in anemia, iron metabolism, renal function, inflammatory markers, and lipid profiles compared with baseline (p < 0.05). Additionally, further improvements in these parameters were observed after the transition from rHuEPO to Roxadustat (p < 0.05). Compared with rHuEPO group, the Roxadustat group exhibited significantly greater increases in hemoglobin, red blood cell count, total iron-binding capacity, transferrin, and serum iron (p < 0.05). Conclusions: In non-dialysis DKD patients with anemia, rHuEPO can significantly decrease HbA1c values, while Roxadustat does not. Roxadustat offers advantages over rHuEPO in terms of efficacy and assessment of glycemic control. Full article