Search Results (3,164)

To improve the dry-machining performance of a traditional-coated cemented carbide tool when cutting the laser-clad Cr-Ni-based steel, TiN/DLC multilayer coatings were fabricated using physical vapor deposition (PVD). The coated tools were tested for their surface and cross-sectional morphology, roughness, and microhardness. Dry-cutting experiments were conducted to compare the performance of a TiN monolayer-coated tool and a TiN/DLC multilayer-coated tool. The results indicated that the TiN/DLC multilayer coatings significantly improved the machining performance, lowered the cutting force and cutting temperature, decreased the average friction coefficient at the rake face, and reduced surface roughness compared to the TiN-coated tool. This improvement is mainly attributed to the low shear strength of the DLC layer, which effectively reduces surface friction and wear of the tool. The main failure modes were abrasive wear and adhesive wear. The results suggest that the composite coating offers a promising approach to improving traditional-coated tool life and enhancing machining efficiency in the dry cutting of laser-clad alloy components. Full article

In recent years, a growing number of studies have focused on improving shear distribution and mitigating stress concentration in PBL shear connectors through the incorporation of composite materials. However, research on Twin-PBL shear connectors remains limited. Therefore, this study employed the finite element method to develop 23 finite element models to evaluate the shear performance of the Twin-PBL rubber-ring shear connector. The results indicate that the Twin-PBL rubber-ring shear connector with a 4 mm thick rubber ring exhibits a 7.5% decrease in shear force and a 71.1% reduction in shear stiffness compared to the conventional Twin-PBL shear connector. Furthermore, parametric analysis reveals that increasing the thickness of the rubber ring reduces both shear capacity and shear stiffness, while higher concrete strength, greater perforated rebar strength, and larger perforated rebar diameter enhance both shear capacity and stiffness. In contrast, the strength of the perfobond steel plate has minimal influence. Based on these findings, a predictive formula is proposed to estimate the shear capacity of the Twin-PBL rubber-ring shear connector. Full article

The aim of this study is to investigate how the positioning of outrigger systems affects the seismic performance of high-rise buildings with either reinforced concrete (RC) shear walls or buckling-restrained braces (BRBs) in the core. Two important questions emerge as the focus and direction of the study: (1) How does the structural performance change when outriggers are placed at various positions? (2) How do outrigger systems affect structural behavior under sequential earthquake scenarios? Nonlinear time history analyses were employed as the primary methodology to evaluate the seismic response of the two reinforced concrete buildings with 24 and 48 stories, respectively. Each building type was developed for two different core configurations: one with a reinforced concrete shear wall core and the other with a BRB core system. Each analysis model also includes outrigger systems constructed with BRBs positioned at different floor levels. Five sequential ground motion records were used to assess the effects of main- and aftershocks. The analysis results were evaluated not only based on displacement and force demands but also using a damage measure called the Park-Ang Damage Index. In addition, displacement-based metrics, particularly the maximum inter-story drift ratio (MISD), were also utilized to quantify lateral displacement demands under consecutive seismic loading. With the results obtained from this study, it is aimed to provide design-oriented insights into the most effective use of outrigger systems formed with BRB in high-rise RC buildings and their functions in increasing seismic resistance, especially in areas likely to experience consecutive seismic events. Full article

One of the key measures of cutting tool efficiency in machining processes is tool wear. In recent decades, numerical modeling of this phenomenon—primarily through finite element cutting models—has gained increasing importance. A crucial requirement for the reliable application of such models is the selection of an appropriate friction model, which strongly affects the accuracy of wear predictions. However, choosing the friction model type and its parameters remains a nontrivial challenge. This paper examines the effect of different friction model types and their parameters on the Archard and Usui wear model indicators, as well as on the main cutting process characteristics: cutting force components, temperature in the primary cutting zone, contact length between the tool rake face and the chip, shear angle, and chip compression ratio. To evaluate their impact on predicted tool wear—expressed qualitatively through the wear indicators of the aforementioned models—several widely used friction models implemented in commercial FEM software were applied: the shear friction model, Coulomb friction model, hybrid friction model, and constant tau model. The simulated values of these cutting process characteristics were then compared with experimental results. Full article

Pile-anchor foundations, serving as one of the anchoring solutions to ensure the safety and stability of floating offshore wind turbines, are primarily subjected to inclined loading induced by anchor chain forces, resulting in significantly different bearing behavior compared to conventional vertically loaded pile foundations. However, experimental research on the inclined pullout performance of anchor piles remains insufficient. To address this gap, this study employs a self-developed servo-controlled loading system to investigate the pullout bearing characteristics of anchor piles in dry and saturated sand, considering factors such as pullout angle and loading point depth. The research results show that from the load–displacement curve of the model pile, it can be found that with the increase in displacement, the load it bears first gradually increases to the peak, then decreases, and then gradually stabilizes. The loading angle has a significant impact on the bearing performance of pile-anchor foundations. As the loading angle increases, the failure mode shows pullout failure. When the loading angle increases from 30° to 60°, the bearing performance of the pile foundation decreases by approximately 63%. When the depth of the loading point increases from 0.22 times the pile length to 0.78 times the pile length, the diagonal anchor tensile bearing capacity of the model pile increases by approximately 45%. When the depth of the loading point is the same, the distribution patterns of bending moment and shear force are basically similar. However, the smaller the loading angle, the larger the value. This is because the horizontal load component plays a dominant role. The compression of the piles above and below the loading point, as well as the bending moment, shear force and axial force under saturated sand conditions, are similar to those in dry sand, but their values are reduced by about 50%. It can be seen that the soil conditions have an influence on the bearing characteristics of pile foundations. Full article

Recent advances in cardiovascular imaging have revolutionized the assessment and management of abdominal aortic aneurysm (AAA) through the integration of sophisticated haemodynamic biomarkers. This comprehensive review evaluates the clinical utility and mechanistic significance of multiple biomarkers in AAA pathogenesis, progression, and treatment outcomes. Advanced cardiac imaging modalities, including four-dimensional magnetic resonance imaging (4D MRI), computational fluid dynamics (CFD), and specialized echocardiography, enable precise quantification of critical haemodynamic parameters. Wall shear stress (WSS) emerges as a fundamental biomarker, with values below 0.4 Pa indicating pathological conditions and increased risk for aneurysm progression. Time-averaged wall shear stress (TAWSS), typically maintaining values above 1.5 Pa in healthy arterial segments, provides crucial information about sustained haemodynamic forces affecting the vessel wall. The oscillatory shear index (OSI), ranging from 0 (unidirectional flow) to 0.5 (purely oscillatory flow), quantifies directional changes in WSS during cardiac cycles. In AAA, elevated OSI values between 0.3 and 0.4 correlate with disturbed flow patterns and accelerated disease progression. The relative residence time (RRT), combining TAWSS and OSI, identifies regions prone to thrombosis, with values exceeding 2–3 Pa⁻¹ indicating increased risk. The endothelial cell activation potential (ECAP), calculated as OSI/TAWSS, serves as an integrated metric for endothelial dysfunction risk, with values above 0.2–0.3 Pa⁻¹ suggesting increased inflammatory activity. Additional biomarkers include the volumetric perivascular characterization index (VPCI), which assesses vessel wall inflammation through perivascular tissue analysis, and pulse wave velocity (PWV), measuring arterial stiffness. Central aortic systolic pressure and the aortic augmentation index provide essential information about cardiovascular load and arterial compliance. Novel parameters such as particle residence time, flow stagnation, and recirculation zones offer detailed insights into local haemodynamics and potential complications. Implementation challenges include the need for specialized equipment, standardized protocols, and expertise in data interpretation. However, the potential for improved patient outcomes through more precise risk stratification and personalized treatment planning justifies continued development and validation of these advanced assessment tools. Full article

This study investigates the application of laser spot welding to join protective housing components in the automotive electronics industry. The PBT GF 30 components were joined using two primary configurations: a purely overlapping joint and a top-overlap joint, both autogenous (i.e., without filler material). To complement the experimental analysis, a numerical model, previously validated for a simpler joint configuration, was adapted and applied to configurations beyond the overlapping and top-overlap joint, more representative of practical automotive industry components. The results demonstrated that butt-overlap joints exhibited significantly higher strength (85% increase) than purely overlapping joints. This enhancement is attributed to the combined effect of normal and shear stresses in the top-overlap configuration, whereas purely overlapping joints rely solely on shear stress. The validated numerical model accurately predicted the experimental results, including displacement and force values. While minor deviations were observed, the numerical model’s predictions converged within the average experimental values and standard deviation, demonstrating that such a model can be used to precisely design laser-welded joints for similar applications. Full article

The inclusion of meat quality traits in breeding programs is a promising strategy to improve beef by selecting animals based on both growth and meat quality. This study aimed to estimate genetic parameters for average daily gain (ADG) and Warner–Bratzler shear force (WBSF), as well as to perform genome-wide association studies (GWAS) to identify genomic regions and transcription factor (TF) binding sites associated with both traits in Nelore cattle. Genetic parameters were estimated using a bi-trait Bayesian model, and GWAS identified key SNPs explaining over 1% of variance in genomic estimated breeding values. Candidate genes near these SNPs were annotated, TF binding sites predicted, and gene–TF networks constructed. Genetic estimates indicated moderate heritability for ADG, low heritability for WBSF, and a small negative genetic correlation between traits. Genomic regions contained 116 and 151 candidate genes for ADG and WBSF, respectively, with 35 shared between traits. Functional analyses highlighted MYBPC1 and PENK for WBSF, and GHRS and NPY for ADG. TF analysis identified 25 TFs, with 3 key ones highlighted. Gene–TF networks revealed candidates including CAPN1 and LTBP3 for WBSF, and CARM1 and GH1 for ADG. Shared candidate genes identified in the combined network provide valuable insights into the genetic architecture of growth and tenderness in Nelore cattle. Full article

This study investigates the development of axial force in micro anti-slide piles under soil movement during slope stabilization. Axial force arises from two primary mechanisms: axial soil displacement ($z_{\mathrm{s}}$) and pile kinematics. The former plays a dominant role, producing either tensile or compressive axial force depending on the direction of $z_{\mathrm{s}}$, while the kinematically induced component remains consistently tensile. A sliding angle of $\alpha =5°$ represents an approximate transition point where these two effects balance each other. Furthermore, the two mechanisms exhibit distinct mobilization behaviors: $z_{\mathrm{s}}$-induced axial force mobilizes earlier than both bending moment and shear force, whereas kinematically induced axial force mobilizes significantly later. The study reveals two distinct pile–soil interaction mechanisms depending on proximity to the slip surface: away from the slip surface, axial soil resistance is governed by rigid cross-section translation, whereas near the slip surface, rotation-dominated displacement accompanied by soil–pile separation introduces significant complexity in predicting both the magnitude and direction of axial friction. A hyperbolic formulation was adopted to model both the lateral soil resistance relative to lateral pile–soil displacement (p-y behavior) and the axial frictional resistance relative to axial pile–soil displacement (t-z behavior). Soil resistance equations were derived to explicitly incorporate the effects of cross-sectional rotation and pile–soil separation. A novel beam-spring finite element method (BSFEM) that incorporates both geometric and material nonlinearities of the pile behavior was developed, using a soil displacement-driven solution algorithm. Validation against both numerical simulations and field monitoring data from an engineering application demonstrates the model’s effectiveness in capturing the distribution and evolution of axial deformation and axial force in micropiles under varying soil movement conditions. Full article

The common iliac artery supplies blood to the lower extremities, and stenosis in this region severely impacts hemodynamics. This study investigates the effects of 25%, 50%, and 75% iliac artery stenosis on key hemodynamic parameters using a fluid–structure interaction (FSI) approach. Semi-idealized geometries reconstructed from patient-specific data modeled realistic arterial behavior. Parameters such as wall displacement, time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), high oscillatory low shear magnitude (HOLMES) index, and endothelial cell activation potential (ECAP) were evaluated. Results showed peak wall displacement of 2.85 mm in the bifurcation zone under 75% stenosis. TAWSS increased with stenosis severity, peaking in stenotic regions and decreasing significantly downstream. OSI was highest in non-stenosed right branches and bifurcation areas, indicating multidirectional shear forces. HOLMES values were lowest downstream of stenoses, indicating disturbed flow. ECAP exceeded the thrombosis risk threshold (1.4 Pa⁻¹) in post-stenotic zones under 75% stenosis, suggesting a higher risk of clot formation. These results demonstrate that stenosis disrupts local flow and causes hemodynamic changes downstream, emphasizing the need for comprehensive clinical assessment beyond the stenotic site. Regions with elevated ECAP and low HOLMES downstream may be prone to thrombosis, highlighting the importance of careful hemodynamic monitoring for treatment strategies. Full article

Glacial lake outburst floods (GLOFs) represent increasingly common and high-magnitude geohazards across the cryosphere of the Tibetan Plateau, particularly under ongoing climate warming and glacier retreat. This study combines multi-temporal remote sensing imagery and detailed Flo-2D hydrodynamic modeling to investigate the erosive dynamics of the 2020 Jinwuco GLOF in Southeastern Tibetan Plateau. Key conclusions include: (1) The 2.35 km-long flood routing channel exhibits pronounced non-uniformity in horizontal curvature, channel width, and cross-sectional shape, significantly influencing flood propagation; five representative cross-sections divide the channel into six distinct segments. (2) Prominent lateral erosion occurred proximally to the dam, attributable to extreme erosive forces and high sediment transport capacity during peak discharge, with horizontal channel curvature further amplifying local impact and erosion. (3) Erosion rates were highest near the dam and in downstream narrow segments, while mid-reach sections with greater width experienced lower erosion. (4) Maximum flow depths reached 28.12 m in topographically confined reaches, whereas peak velocities occurred in upstream and downstream curved sections. (5) The apparent critical erosive shear stress of bank material is controlled not only by soil strength but also by flood dynamics and pre-existing channel morphology, indicating strong feedback between flow dynamics, channel morphology, and critical erosive shear stress of bank material. This study provides a generalized and transferable framework for analyzing GLOF-related erosion in data-scarce high-altitude regions, offering critical insights for hazard assessment, regional planning, and risk mitigation strategies. Full article

Mechanical stress on the glomerular filtration barrier (GFB) exposes podocytes to hydrostatic pressure. Their mechanosensitivity is established, yet the underlying mechanotransduction pathways and responses under hypertension remain unclear. This review examines the mechanical stresses experienced by podocytes in both physiologic and hypertensive conditions and updates the latest extracorporeal techniques used to simulate these forces. Additionally, this review discusses how podocytes respond to these mechanical forces and elucidates the detailed molecular mechanisms involved. Furthermore, we summarize potential protective mechanisms that enable podocytes to withstand mechanical challenges and propose novel therapeutic strategies to delay the progression of hypertensive nephropathy. This review uniquely underscores the importance of biomechanical factors in disease progression and integrates emerging therapeutic strategies targeting podocyte mechanotransduction, offering a novel biomechanical framework for delaying hypertensive nephropathy progression. Full article

As a major source of high-quality protein in China, duck meat such as the renowned Beijing Duck plays a critical role in the poultry industry. Sansui duck, a prized native breed, is valued for its tender meat and rich flavor, yet molecular mechanisms underlying its meat quality remain poorly studied. This study employed metabolomics and proteomics techniques to conduct a comprehensive comparative analysis of the breast and thigh muscles from 90-day-old (90X, 90T) and 468-day-old (468X, 468T) Sansui ducks. The meat quality traits indicated that the shear force and redness (a*) were significantly higher in the 468T and 468X groups compared to the 90X and 90T groups (p < 0.05). Similarly, the shear force values of the 90T and 468T groups were significantly higher than those of the 90X and 468X groups (p < 0.05). Quantitative proteomics analysis revealed differentially expressed proteins (DEPs) significantly enriched in oxidative phosphorylation and ribosomal biogenesis pathways. Non-targeted metabolomics identified differentially expressed metabolites (DEMs) concentrated in amino acid and lipid metabolism pathways. Correlation analysis indicated that in the comparison between 90X and 468X, 18 DEPs and 10 DEMs were closely associated with fleshiness, whereas in the comparison between 468X and 468T, 23 DEPs and 19 DEMs were closely associated with fleshiness. Integrating proteomics and metabolomics data analysis, proteins such as A0A8B9TTI1, R0JRM6, and A0A8B9SQI5, along with metabolites including L-lysine, L-pyrrolidone, and γ-aminobutyric acid from lysine degradation, butanoate metabolism, and 2-oxocarboxylic acid metabolism pathways, can be proposed as key factors influencing meat quality through pathways including lysine degradation, butanoate metabolism, and 2-oxocarboxylic acid metabolism in older ducks. In contrast, the protein R0JXJ3 and metabolites choline and L-glutamine may determine meat quality differences between anatomical sites through the ABC transporter pathway. These findings provide molecular insights and potential biomarkers for genetic breeding and meat quality improvement in Sansui ducks. Full article

Surgical dead spaces are challenging to handle with current preventive methods. Tissue adhesives show promise in obliterating ‘dead spaces’, but the drawbacks of currently available adhesives prevent them from being used for dead space elimination. An adhesive powder based on N-Hydroxysuccinimide-poly(2-oxazoline), NHS-POx, combines robust adhesive strength in moist environments with favorable biocompatibility and biodegradability, which makes this an interesting candidate for eliminating spaces that remain between tissues after surgery. The current study evaluates the swelling, crosslinking speed, and degradation properties of this novel tissue adhesive. These results were then used to design multiple adhesive variants differing in pH, surfactant addition, and particle size, which were subsequently examined based on their wetting rates, adhesive strength, and durability. The powder displayed minimal swelling and rapid crosslinking properties, by which the latter could be increased by a basic buffer or surfactant addition and reduced by increasing particle size. The wetting rate of the powder increased when a surfactant (Pluronic F68) was added to the mix. The adhesive strength, as measured by tensile and shear strength measurements of different prototypes of the adhesive powder, was significantly better than that of a commercially available fibrin glue. The addition of both buffer and Pluronic F68 led to a breakdown of adhesive force after 14 days of incubation, while the prototype containing neither buffer nor Pluronic F68 still had measurable adhesive force after 14 days of incubation. The current study results display several characteristics of the NHS-POx-based tissue adhesive that are favorable for tissue approximation, preventing the occurrence of dead spaces. The most effective and usable adhesive prototype will be identified in further ex vivo and in vivo animal model studies. Full article

The mixing process of powder materials determines the final quality of industrial products. This study employs the Discrete Element Method (DEM) to numerically characterize the effects of particle shape and mixer structure on mixing performance. Using the superquadratic equation, nine types of particles with regular shape variations are constructed, and mixing models are further simulated. The feasibility of superquadratic-generated particles is validated through a classic drum calibration experiment. To investigate the intrinsic mechanisms of particle shape effects, the motion and contact behaviors of particles are quantified by the diffusion index, proportion of rotational kinetic energy, interparticle compressive force, and contact number. Meanwhile, to examine geometry effects, three supplementary mixing simulations are conducted by varying the plow angle and deactivating the choppers. The results show that Cubic particles exhibited poor mixing performance, while disk-shaped particles outperformed cylindrical ones; Increasing the plow blade inclination angle enhanced particle convection and diffusion, whereas excessively small angles may fail to achieve homogeneous mixing; The auxiliary shear of chopper blades promoted particle diffusion, effectively overcoming dead zones between plow blade intervals. Full article