Search Results (493)

In global cold regions and seasonal frozen soil areas, frost heave failure of rock slopes severely endangers infrastructure safety, particularly along China’s Sichuan–Tibet and Qinghai–Tibet Railways. To address this, a meshless numerical model based on the smoothed particle hydrodynamics (SPH) method was developed to simulate progressive frost heave and fracture of water-saturated fissured rock masses—its novelty lies in avoiding grid distortion and artificial crack path assumptions of FEM as well as complex parameter calibration of DEM by integrating the maximum tensile stress criterion (with a binary fracture marker for particle failure), thermodynamic phase change theory (classifying fissure water into water, ice-water mixed, and ice particles), and the equivalent thermal expansion coefficient method to quantify frost heave force. Systematic simulations of fissure parameters (inclination angle, length, number, and row number) revealed that these factors significantly shape failure modes: longer fissures and more rows shift failure from strip-like to tree-like/network-like, more fissures accelerate crack coalescence, and larger inclination angles converge stress to fissure tips. This study clarifies key mechanisms and provides a theoretical/numerical reference for cold region rock slope stability control. Full article

Existing clinical assessments of Parkinson’s disease (PD) primarily focus on stratifying symptom severity or progression rate, which limits their ability to capture changes in functional mobility—an important factor in evaluating rehabilitation outcomes. To address this gap, we developed a novel methodology, the Functional Mobility Assessment for Parkinson’s (FMA-P), which integrates motion capture and pressure-sensitive gait analysis to explore key aspects of functional mobility. Study 1. To develop the FMA-P, we conducted a pilot study involving 12 individuals with PD and 12 age-matched healthy controls, who each completed the FMA-P sequence three times. The sequence included the following tasks: rising from a chair, walking through a doorway, turning, bending to pick up and place an object, and returning to a seated position. Results from Study 1 demonstrated that the FMA-P is a sensitive tool for identifying functional impairments in PD. In particular, significant differences between people with Parkinson’s (PwP) and controls were observed during chair rise (higher peak trunk inclination, p = 0.006; lower mean trunk jerk, p = 0.003) and turning task (longer task duration, p = 0.026 and lower mean heel strike angle, p = 0.007), providing critical insights into postural stability. Study 2. To assess changes in functional mobility over time, we conducted a 12-week repeated-measures intervention study with 12 participants with PD. Results from Study 2 indicated notable improvements in turning stability and balance. Participants demonstrated reduced turning time (p = 0.006) and increased yaw rotation in the head (p = 0.001), trunk (p = 0.002), and pelvis (p = 0.012). In contrast, no significant changes were observed in standard clinical measures (i.e., Timed Up and Go and task duration). The FMA-P offers fine-grained insights into movement quality, making it a valuable tool for early diagnosis, monitoring intervention efficacy, and guiding rehabilitation strategies in individuals with PD. Full article

Chronic inflammation conducts an irreplaceable role in the aging process. More importantly, the impact is particularly significant in scenarios involving cardiac arrest and cardiopulmonary resuscitation (CA/CPR), where elderly individuals are inclined to suffer from more severe inflammatory injuries when compared to younger counterparts. Network pharmacology demonstrated a tight correlation between epicatechin (EC), aging, and the NRG1-NF-κB signaling pathway. With an aim to investigate whether EC suppressing inflammatory aging and alleviating post-CA/CPR brain injury is associated with the inhibition of the NRG1-NF-κB pathway, we established a model of naturally aged 21-month-old rats subjected to CA/CPR. A network pharmacology method was employed to pinpoint possible pathways that connect EC to neuroinflammation associated with aging. Sixty rats were randomly divided into three groups for feeding: a control group (pure water) and EC groups (EC was administered by gavage at doses of 1 mg/kg and 2 mg/kg respectively from the 12th month). Those groups underwent a CA/CPR procedure. At 24-h post-resuscitation, neurological scores, cortical pathology staining and assessments of neural injury were conducted. Expression levels of NRG1-NF-κB pathway-relevant inflammatory factors and proteins underwent systematic investigation by carrying out ELISA, RT-PCR, and Western blotting. In comparison with the 21-month-old groups treated with water, the 21-month-old groups treated with EC at 1 mg/kg and 2 mg/kg demonstrated decreased β-galactosidase staining, aging-correlated proteins and pro-inflammatory factors and NF-κB pathway-relevant proteins, as well as reinforced NRG1-ErbB4 expression. EC lessened inflammatory aging and mitigates post-CA/CPR brain injury in aged rats, associated with the inhibition of the NRG1-NF-κB pathway. Full article

To investigate the longitudinal mechanical behavior of shield tunnels traversing soft and hard heterogeneous strata, a refined three-dimensional numerical model was developed using ABAQUS. The model includes tunnel segments, longitudinal bolts, reinforcement, longitudinal thrust, and additional loading conditions to simulate realistic mechanical responses during construction and operation. The results show that significant differential settlement occurs at the interface between soft and hard soils. Greater joint dislocation is observed on the soft soil side, while joint opening is more pronounced on the hard soil side. Compressive damage concentrates at the soil interface, whereas tensile damage is more severe in soft soil zones. The dislocation at the vault is distributed over a wider area but has a smaller magnitude than that at the arch bottom. Parametric analysis indicates that increasing longitudinal thrust enhances tunnel stiffness and reduces joint dislocation. However, it also leads to increased compressive and tensile damage due to greater trans-verse deformation. Optimizing bolt configuration, including diameter, inclination, and quantity, improves longitudinal stiffness and joint integrity, helping to reduce tensile damage and control deformation. These findings provide theoretical support for the structural design and performance optimization of shield tunnels in complex geological environments. Full article

In the development of tight gas reservoirs in Chuanzhong BJC Gas Field of the Sichuan Basin, running horizontal casing in ultra-long open-hole section faces challenges. These include large friction prediction errors and high casing buckling risks. These challenges significantly impede both the efficiency and safety of field development. Traditional static segmented friction models fail to accurately predict friction coefficients. The reason is that they cannot track dynamic changes in wellbore inclination, azimuth, and dogleg severity in real time. To address this bottleneck, this study develops a technical system termed AI-based dynamic friction inversion-segmented process optimization. Clustering algorithms are used to divide regions. These regions have low, medium, and high friction characteristics. The simulated annealing algorithm dynamically corrects friction coefficients. Meanwhile, the segmented processes of float collars and drilling fluid density are optimized. Verification was conducted on well J108-2H, which features an open-hole section of 4060.9 m and a horizontal-to-vertical ratio (HD/TVD) of 1.88. Results show that this system significantly reduces the mean absolute percentage error of friction coefficient prediction. It also greatly improves the accuracy of casing running feasibility assessment. As a result, the casing in well J108-2H was run smoothly and efficiently. The research results provide an innovative solution for the safe and efficient development of ultra-long open-hole sections in unconventional gas reservoirs. Full article

Comprehensive data are presented for corrosion losses of mild steel exposed for up to 5 years, all obtained from exposing steel coupons at one specific severe marine exposure site on the Pacific Ocean coast. The test programme considered the effects of duration of exposure, inclination, orientation, height, shielding, and coupon variability, using multiple, nominally identical mild steel coupons, all under a single local climatic regime. Such a controlled, consistent, natural environment permits unique, valid comparison of the various influences, both for short-term and longer-term exposures, unlike previous tests of some parameters conducted in the short term at disparate sites. In contrast to coupons exposed only on one side, boldly exposed double-sided coupons corroded severely within 3 years. The effects on corrosion behaviour between individual coupons exposed at different heights and vertical continuous single strips of steel are described. Also reported are corrosion losses for continuous strips and for a series of coupons oriented in different directions. Observations of variability in corrosion losses for nominally identically exposed steel coupons are reported. The effect on corrosion losses with continued exposure to 5 years is reported and compared with information available in the literature. Full article

To mitigate the impact of hydroelectric power plants on downstream fish migration, fish-friendly intakes, combining a low bar spacing rack and several bypasses, are implemented. There are still sites that can be improved thanks to a better bypass design. For this purpose, Computational Fluid Dynamics (CFD) can be a useful tool, even if such devices are still uncommon. This paper investigates the use of a 3D model based on the Reynolds-Averaged Navier–Stokes (RANS) equation for a single phase to simulate the flow in a real-scale water intake equipped with an inclined bar rack and three surface bypasses. The results of numerical simulations are compared to in situ measurements of flow velocities at four cross-sections along the rack, gauging the discharge flowing into the bypasses. The simulated velocities are in accordance with the velocities measured in situ, with a mean square error for the longitudinal velocity ($v_x$) of 0.034 (m²/s²) for the initial simulation and 0.021 (m²/s²) for the improved simulation. The split of the total bypass discharge between the three bypass entrances was satisfyingly predicted by the simulation with the true inlet velocity condition, showing the significant influence of upstream flow non-uniformity. Full article

This study is about Palestinian university students’ attitudes toward English as a foreign language (EFL) learning, paying special attention to variables such as gender, parents’ knowledge of a foreign language, academic year, and travel to English-speaking countries. The researchers implemented a descriptive–analytical design to collect data. The sample of the study is 570 university students across various higher education institutions in Palestine. The researchers used several statistical tests, such as an Independent Sample t-test and one-way ANOVA, to analyse data. The findings suggest that Palestinian university students’ attitudes toward learning English are mainly neutral. However, there are positive inclinations in specific aspects such as travel, academic content, and reading and writing, with no statistically significant differences due to variables such as gender, academic year, or exposure to English-speaking countries. These results suggest that student attitudes are shaped less by personal background and more by broader sociopolitical and educational conditions. This study contributes to the limited body of localised research on affective variables in second language acquisition (SLA) within conflict-affected regions. It highlights the need for contextually responsive pedagogies that promote student engagement and linguistic resilience. Implications are offered for educators, curriculum developers, and policymakers seeking to enhance EFL instruction in Palestine and similar settings. Full article

Background/Objectives: Previous research has demonstrated that the lactate/albumin ratio (L/A) may predict mortality among critically ill patients. Based on pathophysiological rationale, L/A may also correlate with volume status, however such an association has not been investigated extensively. This retrospective cohort study aimed to confirm the prognostic value of L/A and to assess the prognostic value of L/A and its relationship with hypovolemia severity in intensive care unit (ICU) patients. Methods: We analyzed data from consecutive adult patients admitted to the ICU. Admission L/A was evaluated in relation to 30-day mortality and indirect markers of volume status (mean arterial pressure on admission, median dose of norepinephrine and fluid intake within the first 24 h of ICU stay). Results: A total of 1421 patients were included. L/A ≥ 0.06 (estimated on the basis of ROC curve using the Youden index) was an independent predictor of 30-day mortality (HR = 1.423; 95%CI 1.183–1.712; p < 0.001). L/A moderately correlated with markers of absolute or relative hypovolemia, i.e., lower mean arterial pressure (r = −0.353, p < 0.001) on admission, higher norepinephrine dose (r = 0.506, p < 0.001) and greater fluid intake (r = 0.233, p < 0.001) within the first 24 h of ICU stay. Furthermore, L/A ≥ 0.06 on admission was an independent risk factor for the implementation of continuous renal replacement therapy (OR = 2.134; 95%CI 1.652–2.757; p = 0.001). Conclusions: L/A is not only a predictor of poor prognosis but also may be a valuable indirect marker of the extent of hypovolemia in critically ill patients. Further prospective studies are necessary to assess if this parameter should incline a decision for more aggressive fluid management in hypovolemic patients. Full article

This study systematically investigates the influence of varying corrosion severity on the bearing capacity of K-shaped circular-section joints, with explicit consideration of weld line positioning. Four full-scale circular-section joint specimens with clearance gaps were designed to simulate localized corrosion through artificially introduced perforations, and axial static loading tests were performed to assess the degradation of structural performance. Experimental results indicate that the predominant failure mode of corroded K-joints manifests as brittle fracture in the weld-affected zone, attributable to the combined effects of material weakening and stress concentration. The enlargement of corrosion pit dimensions induces progressive deterioration in joint stiffness and ultimate bearing capacity, accompanied by increased displacement at failure. A refined finite element model was established using ABAQUS. The obtained load–displacement curve from the simulation was compared with the experimental data to verify the validity of the model. Subsequently, a parametric analysis was conducted to investigate the influence of multiple variables on the residual bearing capacity of the nodes. Numerical investigations indicate that the severity of corrosion exhibits a positive correlation with the reduction in bearing capacity, whereas web-chord members with smaller inclination angles demonstrate enhanced corrosion resistance, when θ is equal to 30 degrees, K_s decreases from approximately 0.983 to around 0.894. Thin-walled joints exhibit accelerated performance deterioration compared to thick-walled configurations under equivalent corrosion conditions. Furthermore, increased pipe diameter ratios exacerbate corrosion-induced reductions in structural efficiency, when the corrosion rate is 0.10, β = 0.4 corresponds to K_s = 0.98, and when β = 0.7, it is approximately 0.965. and distributed micro-pitting results in less severe capacity degradation than concentrated macro-pitting over the same corrosion areas. Full article

The solar angle of incidence is the angle between the sunlight and the normal on the impact surface. The lower the angle of incidence, the more sun radiation the surface can absorb. There are several methods for calculating of this angle. Determining the geographical location of the equivalent surface is one of the lesser-known options. The equivalent surface is a tangential plane to the Earth that is parallel to a reference inclined surface. The geographical coordinates of the point of tangency are clearly determined by the slope and aspect. Since the equivalent surface is horizontal, basic solar geometry equations apply. Unlike the conventional equations commonly used today, they provide easily interpretable results. The sunrise and sunset times for an inclined surface and the time of an extreme incidence angle can be calculated directly. Approximate calculations are not necessary. In addition, the geographical approach allows for the hour angle to be determined, as well as the tilt for a given azimuth of the solar panel that is perpendicular to direct sunlight. This new procedure sets the time for regular changes in the horizontal direction of the sun-tracker. The renaissance of the geographical approach for calculating the temporal characteristics, which allows for the use of simple equations and the interpretation of their results, can also benefit agriculture, forestry, land management, botany, architecture, and other sectors and sciences. Full article

(1) Background: The present study aimed to evaluate the effects of fixed orthodontic treatment using the Damon self-ligating system on incisor inclination and soft tissue facial profile. Additionally, the study compared the outcomes of premolar extraction versus non-extraction approaches on these parameters. (2) Methods: This retrospective study included 72 patients who were treated with the Damon self-ligating bracket system (Damon, Ormco, Orange, CA, USA). Thirty-five patients (mean age 12.5 years; 20 girls and 15 boys) underwent premolar extraction (Group Ex), while 37 patients (mean age 12.8 years; 16 girls and 21 boys) were treated without extractions (Group NonEx). Lateral cephalometric radiographs were taken pre- and posttherapeutically, and measurements were conducted using OnyxCeph3™ (Image Instruments, Chemnitz, Germany). (3) Results: Following orthodontic treatment, the upper incisors in group Ex were significantly more retruded (p < 0.01), while the mandibular incisors in group NonEx were significantly more proinclined (p < 0.01). Both lips in group Ex, and the upper lip in the group NonEx, exhibited a greater distance from the esthetic line post-therapy (p < 0.01). The position of the lips relative to the SR line did not significantly change in group Ex, whereas group NonEx showed a significantly increased lip protrusion (p < 0.01). A weak negative correlation (−0.37) was observed between the increased retroclination of the upper incisors and the retrusion of the upper lip relative to the SR line. (4) Conclusions: Premolar extraction, as part of a treatment strategy for cases with severe crowding, combined with Damon™ self-ligating braces, does not adversely affect the soft tissue profile. Full article

In response to the complex challenges posed by gob-side entry retaining in medium-thick coal seams—specifically, severe stress concentrations and unstable surrounding rock under composite roof structures—this study presents a comprehensive field–numerical investigation centered on the 5-200 working face of the Dianping Coal Mine, China. A three-dimensional coupled stress–displacement model was developed using FLAC3D to systematically evaluate the mechanical behavior of surrounding rock under varying roof cutting configurations. The parametric study considered roof cutting heights of 6 m, 8 m, and 10 m and cutting angles of 0°, 15°, and 25°, respectively. The results indicate that a roof cutting height of 8 m combined with a 15° inclination provides optimal stress redistribution: the high-stress zone within the coal rib is displaced 2–3 m deeper into the coal body, and roof subsidence is reduced from 2500 mm (no cutting) to approximately 200–300 mm. Field measurements corroborate these findings, showing that on the return airway side with roof cutting, initial and periodic weighting intervals increased by 4.0 m and 5.5 m, respectively, while support resistance was reduced by over 12%. These changes suggest a delayed main roof collapse and decreased dynamic loading on supports, facilitating safer roadway retention. Furthermore, surface monitoring reveals that roof cutting significantly suppresses mining-induced ground deformation. Compared to conventional longwall mining at the adjacent 5-210 face, the roof cutting approach at 5-200 resulted in notably narrower (0.05–0.2 m) and shallower (0.1–0.4 m) surface cracks, reflecting effective attenuation of stress transmission through the overburden. Taken together, the proposed roof cutting and pressure relief strategy enables both stress decoupling and energy dissipation in the overlying strata, while enhancing roadway stability, reducing support demand, and mitigating surface environmental impact. This work provides quantitative validation and engineering guidance for intelligent and low-impact coal mining practices in high-stress, geologically complex settings. Full article

The plastic deformation during equal-channel angular pressing (ECAP) can be affected by various material- and processing-related factors. For instance, the initial crystal orientation and grain size play an important role in determining the material flow, which may cause localized deformation in terms of macroscopic deformation banding. In this study, we use a continuous cast AA1080 aluminum alloy with coarse columnar grains to analyze the influence of casting texture on the local material flow during ECAP. Billets are extracted with their columnar grains inclined either in the same direction as the ECAP shear plane or opposite to it. Visio-plastic analysis is performed on split billets. The pass is interrupted halfway through the ECAP tool to accurately capture steady-state deformation conditions. Flow lines at several positions within the billet are identified based on the positions of deformed and undeformed marker points and fitted to a phenomenological model based on a super-ellipse function. For further characterization, hardness measurements, optical and electron microscopy are carried out on the ECAP-deformed samples. Significant differences in terms of local material flow and microstructure evolution regarding the resulting crystal orientation and deformation banding are observed. Our results confirm and emphasize the importance of initial grain size and texture effects for ECAP processing. Full article

Eclipsing cataclysmic variables (CVs) are key targets for determining binary system parameters through photometric modeling, yet many of them remain poorly characterized. In this work, we present a list (catalog) of 37 confirmed eclipsing CVs selected based on high-quality and publicly available TESS photometric data. The sample includes both long-period systems (with orbital periods exceeding 4 h), such as Z Cam, U Gem, and nova-like variables, as well as a significant number of SW Sextantis stars. Selection criteria required the presence of clearly defined eclipses and sufficient signal-to-noise ratios for reliable analysis. The catalog provides a foundation for phase-folded light curve studies and future modeling efforts aimed at deriving key physical parameters such as component masses, radii, inclinations, and accretion geometries. Notably, several systems, such as V482 Cam, OZ Dra, ASASSN-14ix, and others, have no previously published physical parameters. Our list is accessible via a dedicated website, where each system will have a separate page, including data from TESS, AAVSO, and ZTF. This resource is intended to support detailed follow-up studies. It may encourage other research groups with observational and modeling expertise to contribute to the investigation of these promising but understudied systems. Full article