Search Results (1,634)

Background/Objectives: Pharmaceutical preparation technologies can enhance the bioavailability of poorly water-soluble drugs. Ursolic acid (UA) has been found to possess anti-cancer and hepatoprotective properties, demonstrating its potential as a therapeutic agent; however, its hydrophobicity and low solubility present challenges in the development of drug formulations. This study investigates the preparation of a nano-UA suspension by wet grinding, researches the influence of process parameters on particle size, and explores the rules of particle breakage and agglomeration by combining model fitting. Methods: Wet grinding experiments were conducted using a laboratory-scale grinding machine. The particle size distributions (PSDs) of UA suspensions under different grinding conditions were measured using a laser particle size analyzer. A single-factor experimental design was employed to optimize operational conditions. Model parameters for a population balance model considering both breakage and agglomeration were determined by an evolutionary algorithm optimization method. By measuring the degree to which UA inhibits the colorimetric reaction between salicylic acid and hydroxyl radicals, its antioxidant capacity in scavenging hydroxyl radicals was indirectly evaluated. Results: Wet grinding process conditions for nano-UA particles were established, yielding a UA suspension with a D50 particle size of 122 nm. The scavenging rate of the final grinding product was improved to three times higher than that of the UA raw material (D50 = 14.2 μm). Conclusions: Preparing nano-UA suspensions via wet grinding technology can significantly enhance their antioxidant properties. Model regression analysis of PSD data reveals that increasing the grinding mill’s stirring speed leads to more uniform particle size distribution, indicating that grinding speed (power) is a critical factor in producing nanosuspensions. Full article

Temperature is a key factor in regulating interfacial behaviors and enhancing oil recovery during low-salinity water flooding in tight sandstone reservoirs. This study systematically investigates the synergistic mechanisms of temperature and salinity on ion exchange, wettability alteration, interfacial tension, and crude oil desorption. The experimental results show that elevated temperature significantly strengthens the oil–water–rock interactions induced by low-salinity water, thereby improving oil recovery. At 70 °C, the release of divalent cations such as Ca²⁺ and Mg²⁺ from the rock surface is notably enhanced. Simultaneously, the increase in interfacial electrostatic repulsion is evidenced by a shift in the rock–brine zeta potential from −3.14 mV to −6.26 mV. This promotes the desorption of polar components, such as asphaltenes, from the rock surface, leading to a significant change in wettability. The wettability alteration index increases to 0.4647, indicating a strong water-wet condition. Additionally, the reduction in oil–water interfacial zeta potential and the enhancement in interfacial viscoelasticity contribute to a further decrease in interfacial tension. Under conditions of 0.6 PW salinity and 70 °C, non-isothermal core flooding experiments demonstrate that rock–fluid interactions are the dominant mechanism responsible for enhanced oil recovery. By applying a staged injection strategy, where 0.6 PW is followed by 0.4 PW, the oil recovery reaches 34.89%, which is significantly higher than that achieved with high-salinity water flooding. This study provides critical mechanistic insights and optimized injection strategies for the development of high-temperature tight sandstone reservoirs using low-temperature waterflooding. Full article

Conducted against the background of a highway project in Zhuji, Zhejiang Province, this study investigates the deterioration behavior of tuffaceous sandstone under the combined action of acid rain and wet–dry cycles. Laboratory experiments were carried out to explore its mechanical properties and damage evolution mechanisms. Standard specimens prepared from field rock samples were subjected to wet–dry cycles using an acidic solution with pH ≈ 5.0. By integrating uniaxial compression, Brazilian splitting, ultrasonic wave monitoring, and acoustic emission techniques, a systematic analysis was carried out to evaluate the degradation of mechanical parameters, the evolution of wave velocity, and the underlying damage and failure mechanisms. The results indicate the following: (1) With the increase in the number of acidic dry–wet cycles, the compressive and tensile strengths of tuffaceous sandstone decrease significantly; the deterioration rate first decreases and then increases, with 150 cycles identified as the critical threshold for strength deterioration, beyond which the material enters a stage of rapid degradation. (2) The evolution of ultrasonic wave velocity shows a significant negative correlation with strength deterioration, and the attenuation rate of wave velocity exhibits a consistent trend with the number of cycles as that of strength deterioration. (3) Acoustic emission RA-AF analysis reveals that tensile cracks in tuffaceous sandstone gradually decrease while shear cracks slowly increase, with cracks primarily developing along the weakly cemented tuffaceous areas. (4) This study established fitting formulas for the deterioration of compressive and tensile strengths with the number of cycles, as well as a damage calculation formula based on changes in wave velocity. (5) This study provides practical support for mitigating natural disasters, such as slope instability, induced by this type of combined weathering. Full article

This study addressed the challenges posed by wet-grade maize distiller’s dried grains with solubles (DDGS), which are characterized by high moisture and complex fibers that limit their storage and utilization in poultry feed. Three experiments were conducted to enhance their nutritional value through enzymatic and solid-state fermentation treatments. In vitro pre-digestion using multiple enzymes significantly improved dry matter solubility (DMS) and reducing sugar yield for maize DDGS and the ingredient maize germ meal (MGM). Using optimized parameters, wet-based DDGS-MGM was subjected to solid-state fermentation with 500 mg/kg of cellulase and 200 mg/kg of the X1 enzyme (a laboratory-developed multi-enzyme complex), and this treatment enhanced both DMS and reducing sugar yield, and the resulting fermented product was subsequently applied in further experiments. In the broiler trial, forty 22-day-old Arbor Acres broilers with similar body weights were randomly assigned to five treatment groups, including the control group, (50% DDGS + 50% MGM) unfermented group, (62.5% DDGS + 37.5% MGM) unfermented group, (50% DDGS + 50% MGM) fermented group, and (62.5% DDGS + 37.5% MGM) fermented group, with eight replicates per treatment (one broiler per replicate). Replacement of 30% of the basal diet with fermented 50:50 DDGS-MGM material significantly increased apparent metabolizable energy (AME) and nitrogen-corrected AME by 2.74 MJ/kg and 2.73 MJ/kg, respectively, corresponding to improvements of 39.60% and 40.81% compared to the unfermented control (p < 0.05). Economic analysis indicated that using 5% fermented DDGS-MGM in feed reduced cost by 20.45 RMB per metric ton. These findings demonstrate that bioprocessing can improve the utilization and economic value of maize processing by-products, although further validation under practical conditions is needed. Full article

Under no-load conditions, the wet clutch of vehicles generates drag torque across a wide speed range, which increases power loss in the transmission system and significantly impacts its efficiency and reliability. To address the clutch drag issue over a wide speed range, this study first establishes a low-speed drag torque model that simultaneously considers the viscous friction effects in both the complete oil film region and the oil film rupture zone of the friction pair clearance. Subsequently, by solving the fluid-structure interaction dynamics model of the friction plates, the collision force between high-speed friction pairs and the resulting friction torque are determined, forming a method for calculating high-speed collision-induced drag torque. Building on this, a unified drag torque model for wet clutches across a wide speed range is developed, integrating both viscous and collision-induced drag torques. The validity of the wide-speed-range drag torque model is verified through experiments. The results indicate that as oil temperature and friction pair clearance increase, the drag torque decreases and the rotational speed corresponding to the peak drag torque is reduced, while the onset of collision phenomena occurs earlier. Conversely, with an increase in oil supply flow rate, the drag torque rises and the rotational speed corresponding to the peak drag torque increases, but the onset of collision phenomena is delayed. Finally, with the optimization objectives of minimizing the peak drag torque in the low-speed range and the total drag torque at the maximum speed in the high-speed range, an optimization design model for the surface grooves of the clutch friction plates is constructed. An optimized groove pattern is obtained, and its effectiveness in suppressing drag torque across a wide speed range is experimentally validated. Full article

Although extensive studies have been conducted on the component ratios and performance of fire extinguishing foams, most research has not explored the coupling relationship between foam wettability and adhesion. Therefore, this study aims to develop an efficient foam extinguishing agent for solid fires by focusing on both wettability and adhesion. First, the influence of chemical functional groups on foam wettability and adhesion was elucidated, and the contributions of individual components to foam properties were experimentally investigated. Second, adhesion and wettability tests revealed a negative correlation between these two properties, consistent with variations in foam solution viscosity and wetting time. Third, a novel adhesion evaluation method was proposed, defined as the time required for foam to flow a fixed distance on inclined wooden surfaces; longer flow times indicated stronger adhesion. Fourth, foaming and fire suppression experiments confirmed the practical performance of the optimized formulations. A composition containing 8 wt% Polyoxyethylene ether and 5 wt% Sulfobetaine yielded a wetting-type foam suitable for rapid cooling, whereas 8 wt% Polyoxyethylene ether combined with 9 wt% Sulfobetaine produced an adhesive-type foam capable of persistent attachment to combustibles. Microscopic observations further demonstrated that foams with superior extinguishing performance developed dense lamellae. Full article

Bimetallic mesoporous photocatalysts were synthesized via a wet impregnation method using SBA-15 as a support, and characterized by UV–visible diffuse reflectance spectroscopy, low-angle X-ray diffraction and N₂ physisorption. Among the tested materials, the Ti/Mn combination exhibited the highest photocatalytic activity in azo dye degradation. To understand this enhanced performance, catalysts with varying Mn loads and calcination ramps were evaluated. Additionally, experiments with radical scavengers (isopropanol, chloroform) and under N₂ insufflation were conducted to identify the active radical species. Catalysts prepared with low Mn content and higher calcination ramps showed the greatest activity, which significantly decreased with isopropanol, indicating hydroxyl radicals as the main reactive species. In contrast, samples with higher Mn content and quicker heating displayed reduced activity in the presence of chloroform, suggesting superoxide radical involvement. Spectroscopic analyses (XPS, UV–Vis DRS) revealed that increasing Mn load promotes the formation of Mn²⁺ over Mn⁴⁺ species and lowers the band gap energy. These findings highlight the direct correlation between synthesis parameters, surface composition and optical properties, providing a strategy for fine-tuning the performance of a photocatalyst. Full article

Existing studies on chloride ion transport in concrete under compressive load had rarely incorporated the influence of the dry–wet time ratio, even though this ratio was a key factor affecting chloride penetration in coastal concrete structures subjected to periodic drying–wetting cycles. This study was therefore motivated to fill this gap and to provide more reliable theoretical support for the durability assessment of such engineering structures. A series of accelerated chloride ion penetration experiments was conducted on concrete under compressive load with different dry–wet time ratios. The effects of the dry–wet time ratio, compressive stress level, and exposure environment on chloride ion transport in concrete were analyzed. A chloride ion diffusion coefficient model that accounted for both the dry–wet time ratio and the compressive stress level was then established and validated. The results showed that the enhancing effect of the dry–wet time ratio on chloride ion transport became significant under relatively high compressive stress. When the dry–wet time ratio was 7:1, the convection zone depths of concrete specimens under no stress and compressive stress were both 5 mm. Moreover, when the compressive stress level was 0.5 times the compressive strength and the dry–wet time ratio was 7:1, the chloride concentration of the specimens increased by an average of 756.4% compared with that under natural immersion. Full article

This study presents a comprehensive spatiotemporal assessment of climatic and bioclimatic conditions across Türkiye for both a historical reference period (1995–2014) and future projections (2020–2099) under two Shared Socioeconomic Pathways (SSP2-4.5 and SSP3-7.0) scenarios using the regional climate model (RCM) COSMO-CLM to downscale large-scale signals to a regional scale at high resolution (0.11). A comparison of the model with ERA5-Land reanalysis data revealed annual biases of +1.41 °C (warm) and −0.28 mm/day (dry), emphasizing the importance of bias correction in regional climate assessments. Bias-corrected future projections indicate a marked warming trend and significant decline in precipitation, especially after the 2060s, with pronounced spatial variability across regions. The most intense warming period of the century is the 2060–2079 period, with an anticipated increase of 0.109 °C/year under the SSP3-7.0 scenario, while, under the SSP2-4.5, it is the 2040–2059 period with an increase of 0.068 °C/year. Bioclimatic variables further illustrate shifts in temperature extremes, seasonal variability, and precipitation patterns. Coastal regions are expected to experience a delay in the onset of wet seasons of 1–2 months, while high-altitude zones show earlier shifts of up to 4 months. Four distinct clusters were identified by using k-means clustering method, each with unique temporal and spatial evolution under both SSP scenarios. Clusters 1 and 2, which predominantly represent continental and interior regions, exhibit a strong association with earlier precipitation onset. Notably, arid and semi-arid conditions expand northward, replacing temperate zones in Central Anatolia. Overall, findings suggest that Türkiye is undergoing a substantial climatic transition toward hotter and drier conditions, regardless of the emission scenario. This study has critical implications for ecological resilience, agricultural sustainability, and water resource management, and offers valuable information for targeted climate adaptation strategies and land-use planning in vulnerable regions of Türkiye. Full article

In the tail rotor transmission system of a high-speed helicopter, the timely supply of lubricating oil to the wet friction clutch during frequent starts and stops has a significant impact on the performance of the transmission system. The oil flow requirements of clutches vary across different operational stages, posing a challenge for traditional centrifugal oil supply methods to meet the demand for flow regulation under such dynamic conditions. This paper proposes a novel two-stage centrifugal oil supply structure capable of achieving superior flow control during various clutch operating phases. An experimentally validated two-phase oil–gas CFD model was established to analyze the effects of operational parameters, such as rotational speed and oil supply pressure difference, as well as structural parameters, on oil supply performance. To enhance oil supply flow rate and efficiency under high-speed conditions (rated speed of 4800 rpm and 85% speed) at a common supply pressure (0.45 MPa), while reducing the pressure at the input shaft interface, key structural parameters were determined and optimized using a combined approach of Taguchi orthogonal experiments and response surface methodology. The results demonstrate that the optimized structure achieves a 142.8% increase in the weighted oil supply flow rate, an 11.1% improvement in oil supply efficiency, and a 7.5% reduction in pressure at the input shaft interface. Full article

We addressed rising drinking water risks in tropical tourism catchments by selecting Sanya as a representative case and developing an integrated 10–16 m remote sensing framework (Sentinel-2, GF-1) with a fuzzy evaluation, combining NDVI, WET, and NDBSI, K–T + NDVI eutrophication mapping, and event-sensitive RUSLE (30 m DEM, nonlinear LS, monthly NDVI-driven C, localized R). Land use mapping shows orchards at 736.46 km² (38.37%) and tourism land at 2.64% (mostly golf), with 86.52% overall accuracy (Kappa 0.84). Basin-wide, 91% of the area experiences slight–mild erosion, intensified near reservoirs; relative to forests (FVC > 80%), orchards (FVC 60–70%) have a 3.2× higher median erosion risk (IQR 2.8–3.6, 95% CI 2.7–3.7). On 10–25° slopes during flood seasons, orchard pesticide/nutrient runoff indices rise 28–46%, and in the Dalong watershed, high-erosion orchard pixels co-locate with pesticide residues by 62% (95% CI 58–66%). Tourism is associated with elevated nearshore chlorophyll-a (Chl-a); the area is generally mesotrophic (0.25–0.75 mg/L), with localized nearshore hotspots > 1.0 mg/L; across monthly composites, nearshore Chl-a exceeds center waters by 130–210%, and in the Dalong Reservoir, the shoreline-to-center ratio is 2.3–3.1 (median 2.7, 95% CI 2.1–3.3) during 2023–2024 flood seasons. Overall, this source-to-sink framework supports forward-looking governance of drinking water sources under dual monsoon and tourism pressures. Full article

This study investigates multi-objective optimization of end-milling parameters for AISI D2 cold-worked tool steel using GC1130-coated carbide inserts under wet machining, focusing on cutting speed and feed rate per tooth values beyond manufacturer recommendations. The objective was to identify parameter settings that minimize surface roughness while maximizing cutting tool life—two performance criteria that often conflict in practice. A full-factorial design of experiments was implemented, varying the cutting speed (220–310 m/min) and feed rate (0.06–0.25 mm/tooth). Response Surface Methodology (RSM) was used to develop predictive models, and a desirability function approach (DFA) was applied to perform multi-response optimization under three weighting schemes. The statistical models showed strong reliability, with R² values of 81.09% for surface roughness and 95.02% for tool life. The optimal settings—220 m/min cutting speed and 0.25 mm/tooth feed—resulted in a tool life of 11.03 min and surface roughness of 0.587 µm. This yielded the highest desirability index (D = 0.8706) under tool-life-prioritized weighting, outperforming other cases by up to 10.69%. These findings offer a practical balance between quality and durability, especially for applications where tool wear is a limiting factor. Full article

Accurate drought assessment is crucial for effective regional water resource management. While reanalysis and remote sensing products enable high-resolution drought assessment, their regional application requires rigorous local validation. This study evaluates nine data combinations, pairing three precipitation products with three evapotranspiration products, to identify the optimal combination for robust SPEI estimation and subsequently to investigate the spatiotemporal variations in drought conditions during 1980–2020 in Zhejiang Province, China. The results indicate that the choice of precipitation product is the dominant factor influencing SPEI accuracy, with the combination of CMFD V2.0 precipitation and GLEAM v4.2a evapotranspiration identified as the most reliable for SPEI estimation across multiple timescales (SPEI1/3/6/12). The long-term trend analysis of the SPEI derived from this optimal data combination reveals significant spatiotemporal heterogeneity: temporally, a pronounced “wetter winters, drier springs” seasonal pattern emerges, posing a substantial threat to agricultural water security; spatially, a distinct divergence shows central/northeastern areas wetting while southern/southeastern regions experience a significant drying trend, particularly for long-term hydrological drought (SPEI12). Additionally, the prevalence of light droughts across the province suggests a sustained baseline of water stress. Attribution analysis further demonstrates that precipitation is the dominant driver of droughts across all timescales. This study contributes both a validated, high-resolution data foundation for regional drought assessment and a scientific basis for targeted drought adaptation strategies. Full article

To enhance the fire suppression performance of Class A foam, this study identifies sodium dodecyl sulfate (SDS) as the primary foaming agent and develops a high-efficiency foam system comprising primary and auxiliary foaming agents, wetting agents, and foam stabilizers. It interprets these macroscopic findings at the molecular level through molecular dynamics simulations. Sixteen formulations were designed using orthogonal experiments and evaluated in terms of surface tension, viscosity, wetting performance, and foam expansion ratio. The results demonstrated that the formulated systems exhibited superior foaming characteristics compared to conventional aqueous film-forming foam (AFFF), while other physicochemical properties were inferior. Two high-performing foam systems were further investigated using molecular dynamics simulations. Analysis of the spatial concentration distributions, diffusion coefficients, and the hydrogen-bonding networks of water molecules revealed 14.3% and 14.2% increases in the peak values of the radial distribution function (RDF) for the two systems modified with auxiliary foaming agents, respectively. The auxiliary foaming agents exhibited synergistic effects with SDS, enhancing its water activation capability. The incorporation of wetting agents reduced the water diffusion coefficients by 4.7% and 21.9%, indicating that sodium bis(2-ethylhexyl) succinate sulphonate (T) interferes less with the primary foaming agent than alcohol ethoxylate (AEO). The selected formulations also demonstrated 4.4% and 3.5% reductions in water hydrogen bonding compared to SDS-only solutions, indicating decreased molecular cohesion and improved water activation. By integrating physicochemical evaluation with molecular simulation, the optimized formulation was determined to be SDS (primary foaming agent), sodium fatty alcohol ether sulfate (auxiliary foaming agent), alcohol ethoxylate (wetting agent), lauryl hydroxysultaine (foam stabilizer), and ethylene glycol butyl ether (cosolvent). Full article

Sandwich panels, widely used in factory and warehouse construction, are highly susceptible to fire due to their fragile surfaces and polyurethane-insulated cores. Such structures facilitate rapid fire spread, significantly increasing the risk of extensive thermal damage. Although conventional measures, such as surface pre-wetting, are commonly utilized, their effectiveness is limited due to rapid evaporation. To address this issue, the current study evaluates the effectiveness of compressed air foam (CAF) applied as a pre-application treatment for delaying fire spread. Full-scale fire experiments were conducted to measure temperature variations across sandwich panel surfaces treated under three different conditions: untreated, water-treated, and CAF-treated. Experimental results indicated that CAF effectively formed a stable insulating barrier, maintaining temperatures well below critical thresholds, compared to untreated and water-treated panels. CAF application demonstrated superior thermal protection, reducing internal temperatures by up to 78% compared to untreated conditions and by 67.5% compared to water-treated conditions. These findings underscore the practical importance of adopting CAF pre-application as a proactive fire mitigation strategy, significantly enhancing fire safety standards in industrial and storage facilities constructed with sandwich panels. Full article