Search Results (180)

Starch systems and their extrudates can be used as edible films, carriers, and encapsulants for bioactive substances in various industries, primarily the food, medicine, and pharmacy industries. Using appropriate modification methods, it is possible to alter their physicochemical properties to improve specific functional parameters, thereby enhancing their application potential. The aim of this study was to characterize potato starch extrudates enriched with two types of edible oils (rapeseed or sunflower) at concentrations of 3%, 6%, and 9%. Chemical modification was carried out using K₂CO₃ as a catalyst. The structure of native and modified starch extrudates was examined using optical/confocal microscopy, FTIR, and LTNA (low-temperature nitrogen adsorption). Analogous starch dispersions were studied using static and dynamic light scattering, SLS/DLS, nephelometric methods, and electrophoretic mobility measurements to determine surface charge levels and stability. Additionally, viscosity curves were determined as a function of time and temperature. It was found that starch extrudates with 6% sunflower oil content showed optimal functional properties, characterized by greater stability, higher structural order, and better oil complexation. These findings directly translate into significant potential applications, including the development of functional products in the food industry. Full article

In order to study the effects of notches on the creep behaviors of GH3230 superalloy, a series of creep tests were conducted on GH3230 superalloy sheets with edge notches at 900 °C and 1000 °C. The creep strain curves and creep life of smooth flat plate specimens were predicted based on the θ parameter method. The results indicated that the second stage of steady-state creep of smooth flat plate specimens dominated the creep process, while the strain rate of notched specimens increased significantly in the third stage. The creep fracture strain gradually decreased with increasing creep load. The creep strain curves obtained based on the θ parameter method were in good agreement with the experimental creep strain curves. The predicted creep life of the smooth flat plate specimens and notch specimens were in good agreement with the experimental results, and all experimental results were within the double dispersion band of the predicted life. Notches exhibited a creep life enhancing effect on GH3230 superalloy under the same net stress level. Both stress concentration factor and the experimental net stress collectively determined the notch life enhancement factor. The higher the experimental net stress, the more pronounced the notch life enhancement effect. Full article

This study investigated the effects of irrigation water salinity on the soil–water characteristic curve (SWCC) using soil samples collected from a typical irrigated area in Yingjisha County, southern Xinjiang. The SWCC was determined experimentally via centrifugation. The correlation degree among influencing factors was evaluated, and a goodness-of-fit assessment of mainstream traditional SWCC models was conducted using MATLAB 2021a. A modified Van Genuchten (VG) model incorporating the influence of irrigation water salinity was developed. The accuracy and reliability of the proposed model were validated through soil column infiltration experiments and numerical simulations. The results demonstrated that the original VG model provided the best fit for loam soils in southern Xinjiang, albeit with non-negligible deviations, indicating the need for further refinement. Significant correlations were identified between soil characteristic indices and model parameters, ranked in descending order of influence as follows: soil dry bulk density > clay content > inorganic salt content > silt content. Soils with higher clay and silt contents, along with greater bulk density, exhibited enhanced water retention capacity, resulting in a flatter SWCC. Although increased irrigation water salinity initially improved the soil’s water absorption capacity, the rate of enhancement gradually diminished with further increases in salinity, ultimately leading to a reduction in overall water retention performance. This study provides a theoretical foundation for the prevention and amelioration of saline soils and also supports the efficient utilization of water resources. Full article

The water retention and permeability characteristics of loess are core factors governing geological disaster prevention and engineering stability in the loess regions of northwest China. This study focuses on Yangling loess, systematically conducting soil water characteristic curve (SWCC) measurements and saturated permeability tests under different initial compaction degrees and water contents using a pressure plate apparatus and a TST-55 permeameter. By combining fitting analyses of the Gardner, Fredlund–Xing, and Van Genuchten SWCC models, the study reveals the influence mechanism of initial conditions on the water retention properties of Yangling loess. Furthermore, the unsaturated hydraulic conductivity of loess was predicted using the Van Genuchten–Mualem model. Finally, a quantitative relationship model between hydraulic conductivity and multiple factors (initial compaction degree, water content, and matric suction) was constructed using the response surface methodology. The results indicate the following: (1) A higher initial compaction degree and water content lead to a higher air entry value of loess, resulting in stronger water retention capacity. Among the three models, the Van Genuchten model exhibits the optimal fitting effect for the SWCC of Yangling loess. Its parameter a (related to the air entry value) decreases significantly with increasing compaction degree, while parameter n (pore size distribution index) increases linearly. The SWCC model, considering compaction degree, established based on these findings, can accurately predict the water retention characteristics in the high suction range (0~1200 kPa). This model’s precision in the high-suction segment is particularly valuable, as it addresses a critical range for engineering applications where soil behavior transitions from near-saturated to highly unsaturated states. (2) When loess transitions from a saturated to an unsaturated state, the hydraulic conductivity decreases up to 10⁴ times. Both increased initial compaction degree and water content lead to a significant reduction in hydraulic conductivity. This drastic reduction highlights the sensitivity of loess permeability to saturation changes, which is attributed to the rapid reduction in interconnected pore channels as soil suction increases and pore spaces are filled or compressed under higher compaction. (3) The response surface prediction model quantitatively reveals the influence weights of various factors on hydraulic conductivity in the order of matric suction > initial compaction degree > initial water content. The model exhibits a high coefficient of determination (R² = 0.9861), enabling rapid and accurate prediction of the hydraulic conductivity of Yangling loess. This high precision confirms that the model effectively captures the complex interactions between the factors, providing a reliable tool for practical engineering calculations. This study provides a new model and experimental basis for the accurate prediction of unsaturated loess hydraulic properties. The proposed SWCC model, considering compaction degree and the response surface model for hydraulic conductivity, offers practical tools for engineers and researchers, facilitating more precise design and risk assessment in collapsible loess areas. Full article

This study develops a novel analytical solution for three-dimensional axisymmetric consolidation of unsaturated soils incorporating radial–vertical composite seepage mechanisms and anisotropic permeability characteristics. A groundbreaking dual orthogonal expansion framework is established, utilizing innovative Bessel–trigonometric function coupling to solve the inherently complex spatiotemporal coupled partial differential equations in cylindrical coordinate systems. The mathematical approach synergistically combines modal expansion theory with Laplace transform methodology, achieving simultaneous spatial expansion of gas–liquid two-phase pressure fields through orthogonal function series, thereby transforming the three-dimensional problem into solvable ordinary differential equations. Rigorous validation demonstrates exceptional accuracy with coefficient of determination R² exceeding 0.999 and relative errors below 2% compared to numerical simulations, confirming theoretical correctness and practical applicability. The analytical solutions reveal four critical findings with quantitative engineering implications: (1) dual-directional drainage achieves 28% higher pressure dissipation efficiency than unidirectional drainage, providing design optimization criteria for vertical drainage systems; (2) normalized matric suction variation exhibits characteristic three-stage evolution featuring rapid decline, plateau stabilization, and slow recovery phases, while water phase follows bidirectional inverted S-curve patterns, enabling accurate consolidation behavior prediction under varying saturation conditions; (3) gas-water permeability ratio k_a/k_w spanning 0.1 to 1000 produces two orders of magnitude time compression effect from 10⁻² s to 10⁻⁴ s, offering parametric design methods for construction sequence control; (4) initial pressure gradient parameters λ_a and λ_w demonstrate opposite regulatory mechanisms, where increasing λ_a retards consolidation while λ_w promotes the process, providing differentiated treatment strategies for various geological conditions. The unified framework accommodates both uniform and gradient initial pore pressure distributions, delivering theoretical support for refined embankment engineering design and construction control. Full article

Conventional methods for testing steroids and hormones (SHs) in environmental samples are exhaustive, complex, and score poorly in sustainability matrices. Therefore, this study evaluates the automated sample preparation approach using the modular Biomek i7 Workstation for the analysis of 27 SHs in wastewater. Method development involved optimizing Ultra Performance Liquid Chromatography–Tandem Mass Spectrometry (UPLC-MS/MS) parameters, preparing wastewater matrix blank, and assessing extraction efficiency using three solid phase extraction (SPE) cartridges. Extraction efficiency trials showed suitability in the order of Hydrophilic–Lipophilic Balance (HLB) > Mixed-Mode Cation Exchange (MCX) > Mixed-Mode Anion Exchange (MAX). The method demonstrated specificity for all targeted SHs, with Cholesterol showing a maximum interfering peak of 17.71% of the quantification limit (LOQ). The method met matrix effect tolerance of ±20% for 26 SHs, while Epi Coprostanol (34.92%) showed signal enhancement >20%. The 8-point calibration curve plotted using automated extraction demonstrated acceptable linearity across the tested range. Spiked studies at low (LQC), middle (MQC), and higher (HQC) quality control (QC) levels (n = 6, repeated on three separate occasions) demonstrated % RSD values within 20% and recoveries ranging from 71.54% to 115.00%. The method met validation criteria, showing reliability in Intra-Laboratory Comparison (ILC) and Blind Testing (BT). The method outperformed the conventional approach in greenness assessment (Complex Modified Green Analytical Procedure Index) and practicality evaluation (Blue Applicability Grade Index), offering an effective and sustainable protocol for environmental testing laboratories. Full article

Background: Despite improved survival outcomes with immune checkpoint inhibitors (ICIs), the treatment response of patients with metastatic melanoma remains highly variable. There is a growing need for reliable, accessible prognostic tools that incorporate clinical and inflammatory markers in order to stratify patients better and guide therapeutic decisions. Methods: We conducted a retrospective cohort study involving 73 patients with metastatic cutaneous melanoma treated with ICIs at a single tertiary center between 2017 and 2024. Baseline clinical and laboratory parameters were collected to calculate the Royal Marsden Hospital (RMH), Gustave Roussy Immune (GRIm) and MD Anderson Immune Checkpoint Inhibitor (MDA-ICI) scores. Overall survival (OS) and progression-free survival (PFS) were analyzed via Kaplan–Meier estimates and Cox proportional hazards models. Prognostic performance was assessed using Harrell’s concordance index (C-index) and receiver operating characteristic (ROC) analysis. Results: The median follow-up was 35.9 months, and the median OS was 22.1 months. All three scores were significantly associated with OS in univariate analysis. In multivariate models, only the RMH (HR: 5.45, p < 0.001) and MDA-ICI (HR: 4.24, p = 0.015) scores remained independent predictors of OS. Harrell’s C-index indicated strong discriminative ability for both RMH (0.742) and MDA-ICI (0.730) scores, whereas the GRIm score demonstrated lower predictive accuracy (0.615). Similarly, ROC curve analysis showed higher AUC values for RMH (0.732) and MDA-ICI (0.739) compared with GRIm (0.595). Conclusions: In this real-world cohort of metastatic melanoma patients treated with ICI, the RMH and MDA-ICI scores demonstrated favorable prognostic performance and outperformed the GRIm score in predicting overall survival. These findings support the clinical utility of RMH and MDA-ICI as practical, accessible tools for prognostic risk stratification in melanoma, though external validation in larger, multicenter cohorts is required. Full article

To accurately assess the seismic damage of high-rise structures under long-period ground motions (LPGMs), a 36-story SRC frame-RC core tube high-rise structure was designed. Twelve groups of LPGMs and twelve groups of ordinary ground motions (OGMs) were selected and bidirectionally input into the structure. The spectral acceleration S_90c considering the effect of higher-order modes was adopted as the intensity measure (IM) of ground motions, and the maximum inter-story drift angle θ_max under bidirectional ground motions was taken as the engineering demand parameter (EDP). Structural Incremental Dynamic Analysis (IDA) was conducted, the structural vulnerability was investigated, and seismic vulnerability curves, damage state probability curves, vulnerability index curves, as well as the probabilities of exceeding performance levels and vulnerability index of the structure during 8-degree frequent, design, and rare earthquakes were obtained, respectively. The results indicate that structural damage is significantly aggravated under LPGMs, and the exceeding probabilities for all performance levels are greater than those under OGMs, failing to meet the seismic fortification target specified in the code. When encountering an 8-degree frequent earthquake, the structure is in a moderate or severe damage state under LPGMs and is basically intact or in a slight damage state under OGMs. When encountering an 8-degree design earthquake, the structure is in a severe damage or near-collapse state under LPGMs and is in a moderate damage state under OGMs. When encountering an 8-degree rare earthquake, the structure is in a near-collapse state under LPGMs and in a severe damage state under OGMs. Full article

Inspired by the self-organizing optimization mechanisms in nature, the leaf venation of the royal water lily exhibits a hierarchically branched fractal network that combines excellent mechanical performance with lightweight characteristics. In this study, a structural bionic approach was adopted to systematically investigate the venation architecture through macroscopic morphological observation, experimental testing, 3D scanning-based reverse reconstruction, and finite element simulation. The influence of key fractal geometric parameters under vertical loading on the mechanical behavior and energy absorption capacity was analyzed. The results demonstrate that the leaf venation of the royal water lily exhibits a core-to-margin gradient fractal pattern, with vein thickness linearly decreasing along the radial direction. At each hierarchical bifurcation, the vein width is reduced to 65–75% of the preceding level, while the bifurcation angle progressively increases with branching order. During leaf development, the fractal dimension initially decreases and then increases, indicating a coordinated functional adaptation between the stiff central trunk and the compliant peripheral branches. The veins primarily follow curved trajectories and form a multidirectional interwoven network, effectively extending the energy dissipation path. Finite element simulations reveal that the fractal venation structure of the royal water lily exhibits pronounced nonlinear stiffness behavior. A smaller bifurcation angle and higher fractal branching level contribute to enhanced specific energy absorption and average load-bearing capacity. Moreover, a moderate branching length ratio enables a favorable balance between yield stiffness, ultimate strength, and energy dissipation. These findings highlight the synergistic optimization between energy absorption characteristics and fractal geometry, offering both theoretical insights and bioinspired strategies for the design of impact-resistant structures. Full article

AlSi10Mg has been one of the most studied and employed aluminum alloys for additive manufacturing via laser powder-bed fusion (L-PBF). The optimization of manufacturing parameters is important for reducing internal defects, including porosity and inadequate surface finishes. In addition, heat treatments, such as T6, are often applied to this alloy, but they degrade the characteristic microstructure obtained via L-PBF additive manufacturing—the fine cellular structures—which may, in turn, detrimentally affect the material’s properties. In this context, a new alternative to this treatment, direct aging (DA), has shown promise in improving the mechanical properties of AlSi10Mg parts produced via L-PBF, since it preserves the cellular microstructure, precipitating silicon-rich nanoparticles within the cells. Understanding how different temperatures and heat treatment times influence the microstructure and, consequently, the properties remains a field to be explored in order to optimize the treatment conditions and achieve better mechanical properties. Thus, the objective of this study was to evaluate the influence of manufacturing parameters and heat treatments on the microstructure and mechanical properties of AlSi10Mg alloy. The optimized manufacturing conditions were 300 W power, 800 mm/s scan speed, 30 µm layer thickness, and an argon atmosphere, which led to lower porosity and better finishing. Samples were heat-treated via DA at 150 °C and 170 °C for different times, as well as undergoing a T6 treatment (solution at 520 °C followed by aging at 150 °C and 170 °C). Initially, the aging curves show higher hardness values for the direct aging condition, compared to the T6 and as-built conditions, reaching a peak hardness of 195 HV for 6h of direct aging. In this way, it was followed with microstructural characterization, which demonstrated that DA maintained the fine cell microstructure of L-PBF and promoted the precipitation of Si nanoparticles, which certainly contributed to the increase in hardness compared to T6, which promoted a structure with coarser precipitates. DA at 170 °C for 6 h increased the tensile strength to 430 MPa, compared to the as-built condition, with a slight loss of ductility. Full article

The rock strata traversed by frozen shafts in coal mines located in western regions are predominantly composed of weakly cemented, water-rich sandstones of the Cretaceous system. Investigating the rheological damage behavior of saturated sandstone under frozen conditions is essential for evaluating the safety and stability of these frozen shafts. To explore the damage evolution and creep characteristics of Cretaceous sandstone under the coupled influence of low temperature and in situ stress, a series of triaxial creep tests were conducted at a constant temperature of −10 °C, under varying confining pressures (0, 2, 4, and 6 MPa). Simultaneously, acoustic emission (AE) energy monitoring was employed to characterize the damage behavior of saturated frozen sandstone under stepwise loading conditions. Based on the experimental findings, a fractional-order creep constitutive model incorporating damage evolution was developed to capture the time-dependent deformation behavior. The sensitivity of model parameters to temperature and confining pressure was also analyzed. The main findings are as follows: (1) Creep deformation progressively increases with higher confining pressure, and nonlinear accelerated creep is observed during the final loading stage. (2) A fractional-order nonlinear creep model accounting for the coupled effects of low temperature, stress, and damage was successfully established based on the test data. (3) Model parameters were identified using the least squares fitting method across different temperature and pressure conditions. The predicted curves closely match the experimental results, validating the accuracy and applicability of the proposed model. These findings provide a theoretical foundation for understanding deformation mechanisms and ensuring the structural integrity of frozen shafts in Cretaceous sandstone formations of western coal mines. Full article

The thermal error caused by the temperature rise in the service condition of the hydrostatic turntable system has a significant impact on the accuracy of the machine tool. The temperature rise is mainly caused by the friction heat of the bearing and the heat of the oil pump. The amount of heat mainly depends on the working parameters, such as the oil supply pressure and the oil film gap. The unreasonable parameter setting will cause the reduction in the internal flow of the hydrostatic bearing and the increase in the oil pump power, which makes the heat of the lubricating oil increase and the heat dissipation capacity decrease during the movement. Based on the established hydrostatic turntable system, in order to explore the main influencing factors of its thermal error, the temperature field model of the component is established by calculating the thermal balance of the key components of the system. The thermal coupling analysis of the component is carried out by using the model, and the temperature rise, deformation and strain curves of the hydrostatic turntable system under different service conditions are obtained. The results show that with the increase in the temperature, the deformation and strain of the bearing increase monotonously. For every 1 °C increase, the total deformation of the bearing increases by about 0.285 $\mathsf{\mu }\mathrm{m}$. The higher the oil supply pressure, the higher the temperature rise in the system. The larger the oil film gap, the lower the temperature rise in the system. The oil supply pressure has a greater influence on the temperature rise and thermal deformation than the oil film gap. This study provides a valuable reference for reducing the thermal error generated by the hydraulic turntable of the ultra-precision lathe. Full article

Nylon reinforced with short carbon fibres exhibits superior mechanical properties. Its use as a feedstock for fused deposition modelling (FDM) can extend its applications to consumer goods and industrial products. To investigate the flexural and impact properties of the FDM-printed short carbon fibre-reinforced nylon, a central composite face-centred (CCF) design with four factors and three levels and the response surface method (RSM) were employed. The four primary process parameters are the extrusion and bed temperatures, printing speed, and layer thickness. The three investigated responses were the flexural strength, flexural modulus, and impact strength. Perturbation curves and contour plots were used to analyse the influences of the individual and two-way interactions of the response parameters, respectively. Second-order statistical models were constructed to predict and optimise the mechanical properties. The optimal comprehensive mechanical properties were determined using a desirability function combined with the entropy weighting method. The predicted results of best comprehensive mechanical properties are 169.881 MPa for the flexural strength, 9249.11 MPa for the flexural modulus, and 29.659 kJ∙m⁻² for the impact strength, achieved under the parameter combination of extrusion temperature of 318 °C, bed temperature of 90 °C, printing speed of 30 mm∙s⁻¹, and layer thickness of 0.1 mm. A small deviation between the predicted and experimental results indicated the high reliability of the proposed method. The optimal outcomes under the studied parameters showed higher robustness and integrity than previously reported results. Full article

In order to improve the uniformity of microwave heating, moving components are often added to the cavity. For higher uniformity or greater industrial processing capacity, samples often perform large-scale movements such as rotating and lifting motion or translational motion on a conveyor belt. The microwave heating algorithm based on the ray-casting method (RCM), as proposed in previous studies, can calculate moving complex-shaped samples, but the calculation efficiency is low when the sample moves on a large scale due to the large refined mesh area. To solve this problem, this study introduced a moving mesh combined with the RCM for calculation purposes. A microwave oven model with a rotating and lifting turntable was selected for the analysis. First, the calculation area was divided into a sliding mesh and a telescopic mesh area. The telescopic mesh area was stretched or compressed at different times, which was equivalent to the translational motion of the sample. Then, the electromagnetic parameters were assigned to each mesh point in combination with the boundary recognition algorithm based on the ray-casting method, and the horizontal motion was calculated while calculating the large-scale translation. The proposed method only needs to refine the mesh in the horizontal motion area, which reduces the number of overall meshes. The electromagnetic field distribution obtained by the model during the heating process was verified by the discrete position method. The surface temperature distribution and the real-time curve of the center point temperature were further compared with the RCM. The results show that the average error of the sample center temperature is 2.5% and the calculation time was reduced to 9.8%, which verified the accuracy and efficiency of the proposed method. Finally, the influence of different lifting and rotating speeds on the heating effect was further explored. Full article

Background: Synchronous computation of coronary angiography-derived fractional flow reserve (CAG-FFR) and coronary angiography-derived index of microcirculatory resistance (CAG-IMR) is a novel coronary angiography-based method for on-site assessment of suspected myocardial ischemia in patients with coronary artery disease (CAD). Methods: This trial is a prospective, multicenter, controlled study designed to assess the diagnostic performance of CAG-FFR and CAG-IMR in patients with suspected myocardial ischemia using wire-based FFR and IMR as reference standards. The functional parameters were calculated using a reduced order computational fluid dynamics solver that incorporates thrombolysis in myocardial infarction (TIMI) frame count and aortic pressure recorded by a disposable invasive pressure sensor. Results: CAG-FFR was computed in 325 patients, demonstrating a patient-level diagnostic accuracy of 95.4%, sensitivity of 95.9%, and specificity of 95.1%. The area under the receiver operating characteristic curve (AUC) of CAG-FFR was 0.977. Patient-specific aortic pressure adoption significantly improved the accuracy of CAG-FFR in the “gray zone” compared to fixed-pressure models. In addition, CAG-IMR was successfully computed in 180 patients, showing a patient-level diagnostic accuracy of 95.5%, sensitivity of 96.4%, and specificity of 95.2%. The AUC of CAG-IMR in diagnosing abnormal coronary microcirculatory dysfunction was 0.973. Conclusions: Synchronous computation of CAG-FFR and CAG-IMR demonstrated higher feasibility and excellent diagnostic accuracy compared to wire-based FFR and IMR, highlighting its clinical potential for CAD evaluation. Full article