Search Results (2,284)

Directional swelling pressure is a critical yet often overlooked factor governing the instability of expansive soil slopes. Most existing studies simplify swelling behavior as a uniform or purely vertical stress, thereby underestimating the distinct contribution of horizontal swelling pressure. In this study, an integrated framework combining the Fuzzy Analytic Hierarchy Process (FAHP), multivariate regression analysis based on 35 expansive soil samples, and three-dimensional strength-reduction numerical modeling was developed to systematically evaluate the mechanistic roles of vertical and horizontal swelling pressures in slope deformation. The FAHP and regression analyses indicate that water content is the dominant factor controlling both the free swell ratio and swelling pressure, leading to predictive relationships that link swelling behavior to fundamental physical indices. These empirical correlations were subsequently incorporated into a three-dimensional numerical model of a representative Neogene expansive soil slope. The simulation results demonstrate that neglecting swelling pressure results in substantial discrepancies between predicted and observed displacements. Vertical swelling pressure induces moderate surface uplift but exerts a limited influence on overall failure patterns. In contrast, horizontal swelling pressure markedly amplifies downslope displacement—by more than four times under saturated conditions—reduces the factor of safety by 24.7%, and promotes the progressive development of a continuous slip surface. These findings clearly demonstrate that horizontal swelling pressure is the dominant driver of progressive failure in expansive soil slopes. This study provides new mechanistic insights into swelling-induced deformation and offers a quantitative framework for incorporating directional swelling stresses into slope stability assessment, design optimization, and mitigation strategies for geotechnical structures in expansive soil regions. Full article

Low-permeability waterflooding reservoirs face numerous challenges, including low productivity per well, inadequate formation pressure maintenance, poor waterflood response, and low water injection utilization efficiency. Illustrated by Bai 153 Block in the Changqing Oilfield, the primary concern has shifted in recent years from fracture water breakthrough to formation blockages. Currently, low-yield wells (≤0.5 t) constitute a significant proportion (27.5%), with a recovery factor of only 0.41%. The effectiveness of stimulation treatments is influenced by reservoir properties, treatment types, process parameters, and production performance. Selecting candidate wells requires collecting and analyzing data such as individual well block characteristics. Evaluating treatment effectiveness involves substantial effort and complexity. Early fracturing treatments exhibited significant variations in effectiveness, and the primary controlling factors influencing fracturing success remained unclear. This paper proposes a big data analysis-based method for evaluating stimulation effectiveness in low-permeability waterflooding reservoirs. Utilizing preprocessed geological, construction, and production data from the target block, an integrated application of the Random Forest algorithm and Recursive Feature Elimination ranks the importance of factors affecting treatments and identifies the block’s main controlling factors. Using these factors as target parameters, a multivariate quantitative evaluation model for fracturing effectiveness is established. This model employs the Pearson correlation coefficient method, Recursive Feature Elimination, and the Random Forest algorithm. Results from the quantitative model indicate that the primary main controlling factors that significantly affect post-fracturing oil increment are production parameters, geological parameters such as vertical thickness, fracture pressure, and oil saturation; engineering parameters such as sand ratio, blowout volume, and fracturing method; and production parameters such as pre-measure cumulative fluid production, production months, and pre-measure cumulative oil production, which are most closely related to post-fracturing oil increment. These parameters show the strongest correlation with incremental oil production. The constructed quantitative model demonstrates a linear correlation rate exceeding 85% between predicted fracturing stimulation and actual well test production, verifying its validity. This approach provides a novel method and theoretical foundation for the post-evaluation of oil increment effectiveness from stimulation treatments in low-permeability waterflooding reservoirs. Full article

Research has demonstrated that incorporating nitrate into animal feed can effectively decrease methane production in ruminants, though its impact on carcass characteristics and meat attributes in Hu sheep requires further investigation. This experiment examined how a dietary inclusion of 3% calcium nitrate (CN) influenced slaughter parameters, meat properties, gut microbial populations, and host gene regulation in Hu sheep. The study involved sixty healthy male Hu sheep aged 120 days with comparable body weights (31.11 ± 3.39 kg), randomly allocated into two groups: a control group receiving standard feed (CON) and a CN-supplemented group. The trial lasted 60 days, including a 15-day adaptation period and a 45-day formal trial period. They were housed individually and fed twice daily (at 8:00 and 18:00). The findings revealed that CN supplementation notably reduced the water loss rate in the longissimus dorsi muscle (LD), elevated meat color brightness, and enhanced the proportion of polyunsaturated fatty acids (PUFA), particularly n-6 PUFA, along with the n-3/n-6 PUFA ratio. Conversely, it reduced the levels of saturated fatty acids such as myristic acid (C14:0) and oleic acid (C18:1n9t). Additionally, the treatment boosted ruminal Ammoniacal nitrogen content and total short-chain fatty acid production, thereby contributing to energy metabolism in the animals. Microbiological examination demonstrated that CN supplementation led to a decrease in Fibrobacterota and Methanobrevibacter populations within the ruminal environment, while promoting the growth of Proteobacteria in the duodenal region. The gene expression profiling of digestive tract tissues showed an increased activity in nitrogen processing genes (including CA4) and oxidative phosphorylation pathways (such as ATP6), indicating an improved metabolic efficiency and acid–base homeostasis in the host animals. These findings demonstrate that CN-enriched diets enhance the carcass characteristics of Hu sheep by modifying intramuscular lipid profiles through gastrointestinal microbial community restructuring and metabolic pathway adjustments. Such modifications affect energy utilization and acid–base equilibrium, ultimately impacting muscle characteristics and adipose tissue distribution, presenting viable approaches for eco-friendly livestock farming practices. Full article

Biomimetic pectoral fin propulsion offers a low-noise, highly maneuverable alternative to conventional propellers for next-generation underwater robotic systems. This study develops a manta ray-inspired dual-servo pectoral fin module with a CPG-based controller and employs it as a single-fin test article in a recirculating water tunnel to quantify its hydrodynamic performance. Controlled experiments demonstrate that the fin generates stable thrust over a range of flapping amplitudes, with mean thrust increasing markedly as the amplitude rises, while also revealing an optimal frequency band in which thrust and thrust work are maximized and beyond which efficiency saturates. To interpret these trends, a quasi-steady CFD analysis using the k–ω SST turbulence model is conducted for a series of static angles of attack representative of the instantaneous effective angles experienced during flapping. The simulations show a transition from attached flow with favorable lift-to-drag ratios at moderate angles of attack to massive separation, deep stall, and high drag at extreme angles, corresponding to high-amplitude fin motion. By linking the experimentally observed thrust saturation to the onset of deep stall in the numerical flow fields, this work establishes a unified experimental–numerical framework that clarifies the hydrodynamic limits of pectoral fin propulsion and provides guidance for the design and operation of low-noise, highly maneuverable biomimetic underwater robots. Full article

The water flooding characteristic curve is a crucial tool in reservoir dynamic analysis, commonly employed to estimate water-driven geological reserves and recoverable reserves. However, due to approximations in theoretical derivations—such as equating average water saturation with outlet saturation or assuming that water cut approaches unity—most conventional curves achieve high accuracy only during the high water-cut stage (>80%). This study eliminates systematic errors and enhances calculation accuracy by establishing an improved water flooding curve equation. Firstly, a theoretical analysis of the error in a WOR (water–oil ratio)-type water flooding characteristic curve is performed. The results demonstrate that as water cut increases, calculated dynamic geological and recoverable reserves gradually rise, approaching actual values only when the water cut exceeds 90%. Secondly, a new type of water flooding characteristic curve is derived by using the Buckley–Leverett water drive oil theory and the Welge equation to modify the saturation approximation. Comparative analysis via reservoir numerical simulation demonstrates that the proposed curve significantly enhances prediction accuracy across all water-cut stages above 50%, outperforming conventional curves. After the water cut reaches 50%, the calculation error of dynamic geological reserves is less than 10%, and the calculation error of recoverable reserves is less than 5%. Field application shows that the new water flooding characteristic curve maintains a stable linear shape under certain development conditions. After the adjustment of development conditions, it jumps to form a new stable straight-line segment, which is conducive to the rapid and accurate evaluation of the adjustment effect. Full article

This study quantitatively analyzed the effects of repetitive fault currents occurring in an accelerator environment on the breaking performance of molded-case circuit breakers (MCCBs). To this purpose, four MCCB samples are subjected to one, two, and three repeated fault tests. The interrupting process is divided into the arc stretch and moving (t₁–t₂) section and the absorption in the splitter plate (t₂–t₃) section, and the energy and time are analyzed. The experimental results show that the total energy consumption increased by an average of 1.8–1.9 times in the second and third tests compared to the first test, and the interruption time is also extended by 1.6–2.0 times. In particular, the energy increase rate in the t₂–t₃ section is the highest, at an average of 220%, indicating that the splitter plate is thermally saturated and significantly affected by hot gas due to repeated breaking. These results imply that the thermal and electrical performances of MCCBs deteriorates in a repetitive fault environment, with the interrupting speed delayed and internal energy loss increased. This study suggests the possibility of energy-based condition diagnosis using the energy consumption ratio of each section. Furthermore, the ratios can be used as basic data for evaluating the reliability of circuit breakers under repetitive failure conditions and building predictive maintenance models. Full article

Underwater images often suffer from luminance attenuation, structural degradation, and color distortion due to light absorption and scattering in water. The variations in illumination and color distribution across different water bodies further increase the uncertainty of these degradations, making traditional enhancement methods that rely on fixed parameters, such as underwater dark channel prior (UDCP) and histogram equalization (HE), unstable in such scenarios. To address these challenges, this paper proposes a multi-operator underwater image enhancement framework with adaptive parameter optimization. To achieve luminance compensation, structural detail enhancement, and color restoration, a collaborative enhancement pipeline was constructed using contrast-limited adaptive histogram equalization (CLAHE) with highlight protection, texture-gated and threshold-constrained unsharp masking (USM), and mild saturation compensation. Building upon this pipeline, an adaptive multi-operator parameter optimization strategy was developed, where a unified scoring function jointly considers feature gains, geometric consistency of feature matches, image quality metrics, and latency constraints to dynamically adjust the CLAHE clip limit, USM gain, and Gaussian scale under varying water conditions. Subjective visual comparisons and quantitative experiments were conducted on several public underwater datasets. Compared with conventional enhancement methods, the proposed approach achieved superior structural clarity and natural color appearance on the EUVP and UIEB datasets, and obtained higher quality metrics on the RUIE dataset (Average Gradient (AG) = 0.5922, Underwater Image Quality Measure (UIQM) = 2.095). On the UVE38K dataset, the proposed adaptive optimization method improved the oriented FAST and rotated BRIEF (ORB) feature counts by 12.5%, inlier matches by 9.3%, and UIQM by 3.9% over the fixed-parameter baseline, while the adjacent-frame matching visualization and stability metrics such as inlier ratio further verified the geometric consistency and temporal stability of the enhanced features. Full article

Background and Objectives: Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive interstitial lung disease characterized by alveolar-capillary membrane remodeling and impaired gas diffusion. The diffusing capacity of the lung for nitric oxide (DLNO) has been proposed as a physiological parameter reflecting membrane diffusing capacity and pulmonary vascular involvement, potentially providing complementary information to diffusing capacity of the lung for carbon monoxide (DLCO). This study aimed to evaluate the role of DLNO in the functional assessment of patients with IPF and its correlation with clinical and echocardiographic outcomes. Materials and Methods: This observational, retrospective study included 35 consecutive IPF patients receiving antifibrotic therapy between February and December 2023. All participants underwent plethysmography, combined single-breath DLNO and DLCO testing, six-minute walk test (6MWT), mMRC dyspnea scale assessment, and echocardiography for the estimation of a higher probability of pulmonary hypertension (PH). Results: DLNO was significantly lower in males compared to females (49.3 ± 16.7% vs. 74.6 ± 16.1%, p < 0.001), with a reduced DLNO/DLCO ratio in men. DLNO correlated with oxygen therapy requirement (p = 0.010) and lower oxygen saturation during the 6MWT (p = 0.021). Patients with higher echocardiographic probability of PH showed markedly reduced DLNO values (17.6 ± 7.6%, p = 0.016) and higher FVC/DLNO ratios (2.31 ± 0.85 vs. 1.65 ± 0.64, p = 0.023), together with lower DLCO levels (p = 0.037). Conclusions: DLNO may complement DLCO in the evaluation of gas exchange and alveolar-capillary dysfunction in IPF. Although preliminary, these findings support the potential clinical utility of DLNO as an adjunct parameter in the functional characterization of IPF. Further multicenter studies are warranted to confirm these results. Full article

This study presents an optimal design combined with comprehensive multiphysics validation to enhance the torque density of a coaxial magnetic gear (CMG) incorporating an overhang structure. Four high non-integer gear-ratio CMG configurations exceeding 1:10 were designed using different pole-pair combinations, and three-dimensional finite element method (3D FEM) was employed to accurately capture axial leakage flux and overhang-induced three-dimensional effects. Eight key geometric design variables were selected within non-saturating limits, and 150 sampling points were generated using an Optimal Latin Hypercube Design (OLHD). Multiple surrogate models were constructed and evaluated using the root-mean-square error (RMSE), and the Kriging model was selected for multi-objective optimization using a genetic algorithm. The optimized CMG with a 1:10.66 gear ratio achieved a 130.76% increase in average torque (65.75 Nm) and a 162.51% improvement in torque density (117.14 Nm/L) compared with the initial design. Harmonic analysis revealed a strengthened fundamental component and a reduction in total harmonic distortion, indicating improved waveform quality. To ensure the feasibility of the optimized design, comprehensive multiphysics analyses—including electromagnetic–thermal coupled simulation, high-temperature demagnetization analysis, and structural stress evaluation—were conducted. The results confirm that the proposed CMG design maintains adequate thermal stability, magnetic integrity, and mechanical robustness under rated operating conditions. These findings demonstrate that the proposed optimal design approach provides a reliable and effective means of enhancing the torque density of high gear-ratio CMGs, offering practical design guidance for electric mobility, robotics, and renewable energy applications. Full article

Reinforced concrete (RC) beams strengthened with carbon-fabric-reinforced cementitious matrix (CFRCM) systems have shown potential for restoring flexural performance, yet their effectiveness under different corrosion levels remains insufficiently understood. This study presents a numerical investigation of the flexural behaviour of simply supported RC beams externally strengthened with CFRCM plates. Refined finite element models (FEMs) were developed by explicitly incorporating the steel–concrete bond-slip behaviour, the carbon fabric (CF) mesh–cementitious matrix (CM) interface, and the CFRCM–concrete substrate interaction and were validated against experimental results in terms of failure modes, load–deflection responses, and flexural capacities. A parametric study was then conducted to examine the effects of CFRCM layer number, steel corrosion level, and longitudinal reinforcement ratio. The results indicate that the baseline flexural capacity can be fully restored only when the corrosion level remains below approximately 15%; beyond this threshold, none of the CFRCM configurations achieved full recovery. The influence of the reinforcement ratio was found to depend on corrosion severity, while increasing CFRCM layers enhanced flexural performance but exhibited saturation effects for thicker configurations. In addition, corrosion level and CFRCM thickness jointly influenced the failure mode. Comparisons with design predictions show that bilinear CFRCM constitutive models are conservative, whereas existing FRP-based design codes provide closer agreement with numerical and experimental results. Full article

This study investigates the relationship between apparent electrical resistivity (ER) and key material parameters governing moisture and pore-structure characteristics of concrete. An experimental program was conducted using six concrete mix designs, where ER was continuously measured under controlled wetting and drying cycles to characterize its dependence on the degree of saturation (DS). Results confirmed that ER decreases exponentially with increasing DS across all mixtures, with R² values between 0.896 and 0.997, establishing DS as the dominant factor affecting electrical conduction. To incorporate additional pore-structure parameters, eight input combinations consisting of DS, porosity (P), water–cement ratio (WCR), and compressive strength (f′c) were evaluated using five machine learning models. Gaussian Process Regression and Neural Networks achieved the highest accuracy, particularly when all parameters were included. SHAP analysis revealed that DS accounts for the majority of predictive influence, while porosity and WCR provide secondary but meaningful contributions to ER behavior. Guided by these insights, nonlinear multivariate regression models were formulated, with the exponential model yielding the strongest predictive capability (R² = 0.96). The integrated experimental–computational approach demonstrates that ER is governed by moisture dynamics and pore-structure refinement, offering a physically interpretable and statistically robust framework for nondestructive durability assessment of concrete. Full article

This study evaluated the effects of dietary linseed cake on the fatty acid profile of meat and abdominal fat, and on growth performance in broiler chickens. A total of 198 birds were randomly allocated to three groups (66 birds/group). The control group (C) received a standard soybean meal-based feed, while the LIN6 and LIN12 groups were fed diets that were supplemented with 6% and 12% linseed cake, respectively. Linseed cake supplementation reduced saturated and monounsaturated fatty acids, increased n-3 polyunsaturated fatty acids (PUFAs) in meat and abdominal fat, and lowered the n-6/n-3 PUFA ratio (FDR-adjusted p < 0.05). The 12% inclusion resulted in a more pronounced accumulation of n-3 PUFAs—4.3–5.0 times higher than the control—while 6% inclusion increased n-3 PUFAs by 2.8–3.3 times (FDR-adjusted p < 0.05). However, 12% inclusion negatively affected growth performance, reducing body weight by 9.9% and feed intake by 10.4% at 42 days (p < 0.05), whereas the 6% inclusion had no adverse impact (p < 0.05). These results indicate that 6% linseed cake represents the optimal practical inclusion level, effectively enhancing the n-3 PUFA profile of broiler meat and abdominal fat without compromising growth, while higher inclusion levels may impair production performance. Full article

Background: Ultra-processed foods (UPFs) have emerged as a critical component of diet quality, yet data on the associations between UPF and nutrient intakes remain limited. This study aimed to evaluate nutrient consumption in relation to UPF intake and adherence to international dietary guidelines for non-communicable disease (NCD) prevention. Methods: Data from 469 individuals aged 2–18 years enrolled in the Hellenic National Nutrition and Health Survey (HNNHS) were analyzed. Intakes were assessed using two 24 h recalls, and foods were classified according to the NOVA system. Participants were categorized by UPF energy intake tertiles. Nutrient adequacy was assessed using Nordic Nutrition Recommendations, European Society of Cardiology guidelines for macronutrients, and the Institute of Medicine’s Estimated Average Requirements and Adequate Intake values for micronutrients. Results: Children in the highest UPF tertile had significantly higher intakes of energy, carbohydrates, added sugars, saturated fats, polyunsaturated fats, and cholesterol, but lower intakes of protein compared to those in the lowest tertile. Fiber intake remained inadequate across all tertiles, with no significant differences. Regarding adherence to NCD prevention guidelines, children in the 3rd UPF tertile had a 2.3 times higher prevalence ratio for exceeding added sugar recommendations, while their protein intake prevalence ratio was 0.8 times lower. For micronutrients, the highest UPF tertile showed significantly elevated intakes of vitamins E, B₁, folate, calcium, iron, copper, and sodium, but lower potassium intake compared to the lowest tertile. Conclusions: Our results underscore the need for effective public health strategies to improve diet quality in children and adolescents and prevent diet-related NCDs. Full article

Background: Acute respiratory distress syndrome (ARDS), recognized as an inflammatory and life-threatening lung injury, is typified by severe hypoxaemia, lack of heart-related pulmonary edema, and bilateral lung infiltrates. Glucocorticoids are anti-inflammatory and immunoregulatory agents that are considered a viable treatment for ARDS. This study sought to contrast the effects of methylprednisolone, hydrocortisone, and dexamethasone at equivalent doses in ARDS. Methods: About 195 ARDS patients were allocated at random to take methylprednisolone (1 mg/kg/day), hydrocortisone (350 mg/day), or dexamethasone (13 mg/day). The primary and secondary outcomes over 28 days following the initiation of glucocorticoid therapy involved mortality, ventilator-free days, duration of hospitalization, duration of intensive care unit (ICU), total number of patients requiring invasive mechanical ventilation, and changes in the means of arterial oxygen partial pressure to inspired oxygen fraction (PaO₂/FiO₂) and oxygen saturation percentage to inspired oxygen fraction (SpO₂/FiO₂) ratios. Results: Over the 28-day follow-up, regarding mortality, there was a significant difference between dexamethasone and hydrocortisone, as well as between methylprednisolone and hydrocortisone. However, methylprednisolone exhibited the lowest mortality. There were no significant differences among study groups in ventilator-free days, hospitalization duration, ICU duration, and requirement for invasive mechanical ventilation. On the other hand, methylprednisolone had the lowest means of both durations of hospitalization and ICU, and the lowest requirement for invasive mechanical ventilation. Each study group exhibited a significant increase in both PaO₂/FiO₂ and SpO₂/FiO₂ ratios at follow-up time. However, dexamethasone showed the highest means of both PaO₂/FiO₂ and SpO₂/FiO₂ ratios at follow-up time. There was a significant difference in PaO₂/FiO₂ and SpO₂/FiO₂ ratios at follow-up assessment between dexamethasone and hydrocortisone. Conclusions: At equivalent doses, treating ARDS with methylprednisolone may be more successful than using dexamethasone and hydrocortisone. Full article

A series of reduced graphene oxide–calcium sodium aluminosilicate (rGO-CSA) composites with various rGO/CSA weight ratios (i.e., rGO/CSA 1/2.5, 1/5, 1/10, and 1/15) were successfully synthesized via hydrothermal reaction of CSA particles and GO nanosheets. The chemical compositions and morphology of as-synthesized rGO-CSA composites were characterized by XRD, SEM, BET and FTIR. Results from SEM revealed that CSA particles were deposited on the surface of rGO nanosheets resulting in rGO-CSA nanocomposites. N₂-BET results showed that rGO-CSA4 composites with an rGO/CSA loading ratio of 1/15 showed a high specific surface area of 824.7 m²/g, which is higher than that of raw rGO (370.7 m²/g) and CSA (719.8 m²/g) materials. According the BET and SEM, it can be confirmed that the combination of rGO with CSA can reduce stacking during the drying process of rGO. The as-prepared rGO-CSA nanocomposites exhibited an excellent performance in the adsorption of methylene blue (MB). The rGO-CSA3 material exhibits an MB saturation adsorption capacity of 66.3 mg/g. Since rGO is the only adsorption-active material in the rGO-CSA3 composite, the rGO (9.09 wt%) in rGO-CSA exhibited an MB saturation adsorption capacity of 729.4 mg/L after content correction, which is far greater than the value of raw rGO material. The rGO-CSA3 composites showed superior adsorption efficiency of MB, mainly due to CSA particles effectively reducing rGO nanosheets stacking during the drying process. Full article