Search Results (988)

This study investigates the effect of chemical modification of xylite—a fraction derived from Polish lignite—using succinic anhydride (SA) on the morphology and mechanical performance of isotactic polypropylene (iPP) composites. Xylite was incorporated at loadings of 1, 10, and 25 wt% and in two particle size ranges (40–63 µm and 63–125 µm), with and without SA (0.5 and 2 wt%). The composites were characterized by wide-angle X-ray scattering (WAXS), Fourier-transform infrared spectroscopy (FTIR), and tensile testing to evaluate crystallinity (Xc), β-phase content (kβ), and mechanical properties. Unmodified xylite reduced crystallinity (Xc down to ~37%) and significantly decreased ductility, with elongation at break strongly negatively correlated with filler content (r ≈ −0.68), indicating poor dispersion and weak interfacial adhesion. In contrast, SA addition (0.5–2 wt%) partially restored crystallinity (up to ~48%) and increased stiffness (Young’s modulus up to 2120 MPa), while altering β-phase content. FTIR analysis indicated reduced intermolecular hydrogen bonding between xylite surface hydroxyl groups in the presence of SA, consistent with interfacial chemical interactions, likely via esterification. The β-phase content showed a moderate positive correlation with xylite loading (r = +0.43) and a negative correlation with elongation at break (r = −0.46), suggesting that excessive β-phase formation may reduce toughness. Larger particles (63–125 µm) provided slightly improved elongation at break and stiffness. Overall, SA acts as both a compatibilizer and a morphology-directing agent, enabling precise control of the stiffness–ductility balance and crystalline structure in iPP/xylite composites. These results establish chemically modified lignite-derived fillers as a viable strategy for engineering cost-efficient polyolefin materials with tunable structure–property relationships, offering strong potential for scalable industrial implementation. Full article

Water-induced deterioration of silty soil subgrade in the lower Yellow River floodplain poses a critical, long-standing engineering challenge. Most existing studies on silty soil modification prioritize strength enhancement via traditional cementitious binders (i.e., cement, lime), yet these strategies fail to fundamentally block water migration in the soil matrix. A distinct scientific gap persists: the capillary water inhibition mechanism of nano-superhydrophobic modified Yellow River alluvial silt, along with the correlation between its microstructural evolution and macroscopic engineering performance, has yet to be systematically elucidated. To fill this gap, we conducted hydrophobic modification of the targeted silt using a nano-superhydrophobic material (NSHM), and performed a systematic suite of laboratory tests to characterize its hydrophobicity, mechanical properties, water stability, and microstructural characteristics. Quantitative experimental results demonstrate that NSHM imparts remarkable water resistance to the silt: at an NSHM dosage ≥0.5%, the modified soil exhibits stable superhydrophobicity across all tested compaction degrees, with over a 99% reduction in saturated hydraulic conductivity. Notably, the hydrophobic modification only incurs a <12% reduction in the dry unconfined compressive strength (UCS) of the silt. Microscopic characterization results reveal that NSHM modifies the silt via two core pathways: uniform particle encapsulation and pore infilling, without altering the inherent mineral functional groups of the soil. This microstructural regulation reduces the average pore diameter by 38.2% and total porosity by 15.6%, while optimizing the uniformity of pore size distribution. Based on comprehensive evaluation of overall performance, a minimum NSHM dosage of 0.5% is recommended for in situ application in local silty soil subgrade. This study provides critical theoretical guidance and technical support for water damage mitigation in alluvial silty soil subgrade. Full article

Cyclocarya paliurus polysaccharides (CPP) possess various physiological functions such as lipid-lowering and antioxidant activities. However, as a complex plant-based dispersion system, the interfacial characteristics of fermented C. paliurus beverages often restrict the release of bioefficacy of the active ingredients. This study investigated the impact of particle size on the colloidal stability and lipid-lowering activity of C. paliurus beverages fermented by Lactobacillus plantarum and established an empirical correlation between the two. While the 200–300 mesh fraction showed superior physical stability, the 40–60 mesh fraction was identified as the optimal formulation in this study when balancing ROS indicators. In vivo assays using Caenorhabditis elegans demonstrated that the 40–60 mesh formulation significantly reduced MDA levels and inhibited lipid accumulation, decreasing TG content by 19–46%. Notably, the average diameter of lipid droplets decreased by 38.4%, promoting the conversion of large storage-type droplets to small/medium-sized droplets with high metabolic activity. This study reveals the trade-off between physical dispersibility and bioavailability, providing a theoretical basis for optimizing the interfacial structure of functional plant-based beverages. Full article

Wear remains a dominant cause of performance loss and premature failure in mechanical components, motivating the development of environmentally benign surface-engineering solutions. Among thermal spray systems, high-velocity oxy-fuel (HVOF)-sprayed WC-Co coatings are widely applied under severe wear conditions. The development of nanophase coatings offers the potential for enhanced mechanical performance. However, retaining the nanostructure and limiting decarburization during deposition remain key challenges. In this study, nanophase WC-12Co feedstocks with two particle size ranges, together with Al-modified nanophase powders, were used to deposit coatings under optimized HVOF spraying conditions (spray distance 200 mm, reduced O₂/fuel ratio, and high particle velocity) and were benchmarked against a conventional WC-12Co (12 wt.% Co) coating. The coatings were characterized in terms of microstructure and phase constitution (OM, SEM/EDS, XRD) as well as thickness, porosity (0.5–3.6%), adhesion strength (up to 65 MPa), and microhardness (~1040–1210 HV). Tribological behavior was assessed by ASTM G99 pin-on-disk testing and counterbody wear was quantified via geometric volume loss estimations. The use of larger nanophase particles enabled effective nanostructure retention with limited decarburization, whereas reducing particle size intensified decarburization, promoting increased W₂C formation, and markedly reduced coating cohesion, despite lower porosity and higher hardness. Aluminum additions enhanced coating microhardness and suppressed Co₃W₃C formation, indicating improved phase stability with minimal additional decarburization. Although coating wear remained negligible for all systems, Al-containing coatings exhibited increased friction (up to 35%) and significantly higher counterbody wear (up to sevenfold) compared to the Al-free nanophase coating, which was found to correlate with coating microhardness. Overall, the results demonstrate that optimizing nanophase WC-Co coatings requires balancing competing mechanisms between microstructural stability, cohesive integrity, and tribological response, highlighting the critical role of feedstock design in tailoring coating performance. Full article

This study presents an experimental investigation of the influence of dopant type and calcination temperature on BaTiO₃-based piezoceramics synthesized by a solid-state calcination process. The effects of Mn, Nb, La, and Ce dopants on the structural, morphological, and piezoelectric characteristics of powders calcined at 1000 °C and 1100 °C were systematically evaluated. In addition, two co-doped BaTiO₃ compositions, namely Mn–Nb and La–Nb, calcined at 1000 °C, were investigated in order to assess the combined effect of acceptor–donor and donor–donor doping strategies on microstructural evolution and structural stability. The synthesized powders were characterized by scanning electron microscopy (SEM), particle size analysis, energy-dispersive X-ray spectroscopy (EDS), elemental mapping, and X-ray diffraction (XRD), in comparison with a commercial BaTiO₃ reference powder. The piezoelectric response was assessed by correlating the structural modifications induced by doping with the estimated piezoelectric coefficient d₃₃, calculated as a function of the tetragonality ratio (c/a) and further correlated with the crystallite size. The results reveal significant variations in grain growth, dopant distribution, and crystallographic stability, highlighting the critical role of dopant chemistry and calcination temperature in tailoring the functional properties of BaTiO₃ for piezoelectric applications. Full article

The lithium resource reserves in Xinjiang’s Dahongliutan reach 1.1 million tons, making it one of the most representative spodumene deposits in China. Through process mineralogy analysis, the ore was identified as having inherent characteristics that control density-based separation: Coarse crystallization, a high monomer dissociation degree, and a density contrast. Based on these mineralogical characteristics, dense-medium separation experiments were conducted to investigate the mineralogically controlled separation behavior as a function of particle size and medium density. Three process flows (two-product, pressureless three-product, and two-stage, two-product) were further designed and comparatively evaluated. It indicated that the dense-medium separation efficiency is positively correlated with the monomer dissociation degree of spodumene, and the 0.5~6 mm size fraction is the optimal particle size range because it achieves a balance between ore crushing dissociation and coarse-grain dense-medium separation adaptation. Furthermore, all three dense media processes can save grinding energy, and each of them has its own advantages and disadvantages. Comprehensively considering the grade of the concentrate, recovery, the grade of the tailings, and grinding energy consumption, it is recommended to adopt a combined process of two-stage, two-product dense-medium separation and flotation. Full article

Galactic cosmic rays (CRs) are a fundamental non-thermal component of the interstellar medium (ISM). Understanding the transport of super-high-energy particles is essential for interpreting observations of Galactic PeVatrons. Classical diffusion models assuming a homogeneous and isothermal medium oversimplify the multiphase ISM. We utilize high-resolution three-dimensional magnetohydrodynamic simulations to self-consistently generate a multiphase ISM—comprising the warm (WNM), unstable (UNM), and cold neutral medium (CNM)—and investigate 1.5–15 PeV particle transport using a test-particle approach. We find that thermal phase transitions induce steep magnetic field strength gradients at phase boundaries, creating localized magnetic fluctuations that act as efficient sites for adiabatic mirror reflections and non-adiabatic pitch-angle scattering, strongly enhancing cross-field transport at these interfaces. However, because phase boundaries occupy only a small volume fraction and particles spend most of their trajectory in the weakly scattering WNM and UNM, the global pitch-angle scattering coefficient in the multiphase ISM is smaller than in an equivalent isothermal medium. This locally strong scattering nevertheless drives both parallel and perpendicular spatial diffusion coefficients to ∼${10}^{30}$ cm² s⁻¹ at 1.5 PeV, with the perpendicular component exceeding its isothermal counterpart (∼${10}^{28}$ cm² s⁻¹) by two orders of magnitude. Using a phase–phase diffusion matrix decomposition, we show that global CR transport is governed by the volume-filling, trans-Alfvénic WNM and UNM, where particles stream along stochastically wandering field lines. Cross-phase displacement correlations are universally positive, indicating cooperative transport between thermal phases. In contrast, the super-Alfvénic CNM acts as an efficient confinement that substantially suppresses local diffusion. Full article

The Changbai Mountain–Liaodong region is a crucial component of the global black soil belt in Northeast China and a significant national grain production base. However, like many high-latitude agricultural regions worldwide, it faces persistent challenges during the spring sowing period, including low soil temperatures and excessive moisture. Therefore, developing region-specific, effective methods of reducing soil moisture and increasing temperature while improving soil fertility is essential for improving agricultural productivity. To this aim, a field experiment was conducted with two factors: a main plot subjected to ridge tillage (RT) and flat tillage (FT) and subplots with biochar (BC) and straw (ST) amendments. A subplot with no amendment (CK) was used as a control. During maize growth, the daily soil temperature and moisture were monitored, and the soil water evaporation rates and physical structure, as well as the maize yield performance, were evaluated. The results showed that biochar and straw application significantly decreased the soil monthly water content by 1.69–2.22% (p < 0.05) in the surface soil layer (0–15 cm) from May to June, with a more pronounced effect under RT. In contrast, biochar application increased soil moisture and water storage from July to September, indicating that the influence of biochar on soil moisture depends on time and field aging processes. Biochar amendment raised the soil maximum temperature by 0.32–0.79 °C in the top 0–15 cm layer, while straw incorporation decreased the minimum soil temperature by 0.11–0.52 °C. The increase in soil temperature was primarily due to the biochar’s darker color, which facilitated solar radiation absorption, while the decrease in soil temperature was caused by the “Wind Leakage Effect” induced by the large particle size of the straw. Biochar and straw incorporation effectively enhanced maize dry matter accumulation by an average of 15.8% and 8.2%, respectively, and grain yield by 13.0% and 7.8%, respectively. Correlation analysis indicates that these increments are primarily due to enhanced soil moisture and available N content during the middle to late stages of maize growth. Therefore, the integration of straw and biochar with high-ridge cultivation is an effective strategy for excessive moisture reduction and warming in spring soil and it also contributes positively to maize yield. Full article

To address the imbalance between the shearing–mixing quality and energy efficiency of deepwater drilling mud mixers and breakthrough the limitations of existing independent single-objective analytical perspectives, the Eulerian solid–liquid two-phase numerical simulation was adopted in this study. Combined with a modified shear rate algorithm and a triple energy coupling analysis of shear rate, Lamb vortex energy and Enstrophy, the energy conversion and particle dispersion mechanisms inside the mixer under variable flow rates and solid concentrations were systematically investigated, and the performance differences between the first-generation and optimized mixers were clarified. Structural optimizations including an additional modular stator with a designed shear gap of 2 mm, improved blade profiles and shear angles to 14.2°, and miniaturized radial dimensions of the impeller and volute were implemented to achieve compact structural upgrading. The results demonstrate that high-energy regions are concentrated in the rotor–stator gap. After optimization, the peak shear rate increases from 12,010 s⁻¹ to 17,092 s⁻¹, representing a 42.3% enhancement. The peak Lamb vortex energy and the mean Enstrophy rise by 8.6% and 18.9%, respectively. Shear rate correlates weakly positively with Lamb vortex energy and strongly negatively with Enstrophy, revealing vortex sensitivity to flow velocity and tight coupling of viscous dissipation to particle concentration. The outlet coefficient of variation C_v decreases by 59.6%. Higher flow rates strengthen the coupling of shear and vortex energy, and higher solid concentrations weaken stator shear performance. The optimized mixer achieves synergistic improvements in shear efficiency and mixing quality, with over 50% enhancement in mud dispersion stability and more than 15%. Full article

Filtration systems are essential for drip irrigation using sediment-laden water sources such as the Yellow River. This study focused on a sand filter (filtration accuracy: 150 μm), a disc filter (filtration accuracy: 125 μm), and their combined multi-stage filtration system (flow rate: 30–50 m³/h). In situ tests were conducted under Yellow River water conditions in the Hetao Irrigation District, Inner Mongolia, China, to evaluate the response of filtration performance to sediment characteristics, flow rate, and operating time. On this basis, Differential Evolution-optimized Random Forest Regression (DE/RFR) was further established to predict filtration performance. The results showed that: (1) Under sediment concentrations of 0.62–3.6 g/L and median particle sizes of 4.70–16.03 μm, the head loss of the sand filter (ΔH_si) remained stable over the operating time. Conversely, the head loss of the disc filter (ΔH_di) increased with the operating time; the magnitude of this increase grew with higher flow rates, sediment concentrations, and median particle sizes, reaching 0.07 MPa after 16–235 min of operation. The head loss of the multi-stage filtration system (ΔH_i) was primarily generated by the disc filter. (2) The filtration efficiency of the filters and the filtration system was 2.5–6.4%. The outlet sediment concentration and particle size distribution were linearly correlated with the inlet values, and the outlet sediment particle size distribution remained below the clogging risk threshold for emitters. (3) Prediction models for ΔH_si, ΔH_di, and ΔH_i were developed based on MLR, RFR, and DE/RFR. Among these, DE/RFR exhibited the highest accuracy in predicting these variables, with R² values ranging from 0.71 to 0.93 and RMSE values from 0.0017 to 0.0104 MPa. (4) Results from Pearson correlation and feature importance analysis indicated that ΔH_si, ΔH_di, and ΔH_i were primarily influenced by flow rate, sediment concentration and operating time, and flow rate and operating time, respectively. (5) Building upon the DE/RFR model, a Filtration Cycle Prediction Model (FCPM) was developed to determine the operational duration required for the head loss across both the filters and the filtration system to reach 0.07 MPa. The two models developed in this study provide technical support for the configuration and operation of drip irrigation filtration systems using sediment-laden water. Full article

High-cycle fatigue (HCF) behavior of multi-scale hybrid composites remains a critical area of investigation for advanced applications in aerospace and automotive industries. This study aims to experimentally investigate and optimize the HCF performance of carbon–Kevlar/epoxy hybrid composites through synergistic incorporation of nano-silica (nSiO₂) and nano-graphene (nGr). Laminates were fabricated using a hand lay-up process followed by press molding, with a [2 carbon fiber/4 Kevlar fiber/2 carbon fiber] stacking sequence. Sixteen material configurations were investigated based on a Taguchi design of experiment (DOE), with two input parameters (nanoparticle percentages) at four different levels each. Following tensile screening tests, three optimal formulations were selected for fatigue evaluation alongside a non-reinforced baseline. Axial fatigue tests were conducted under load-controlled conditions with a stress ratio of R = 0.01 at a constant frequency of 5 Hz. Stress levels were set at 65%, 70%, and 75% of the ultimate tensile strength (UTS), which ranged from 211 MPa for the baseline composite to 390 MPa for the optimal hybrid formulation (1.2 wt.% nSiO₂ and 0.75 wt.% nGr). Scanning electron microscopy (SEM) analysis of fracture surfaces was performed to correlate microstructural features with fatigue performance. The results demonstrate a remarkable synergistic effect. The optimal hybrid nanocomposite exhibited superior fatigue life, sustaining significantly higher maximum stress (253 MPa vs. 137 MPa at 65% UTS) and achieving a life increase of several-fold compared to the non-modified baseline. SEM observations revealed that this enhancement stems from complementary microstructural mechanisms: nSiO₂ particles are uniformly dispersed without agglomeration, providing matrix toughening through crack deflection, while nGr sheets enhance interfacial adhesion, as evidenced by complete matrix coverage on fiber surfaces. The optimal formulation uniquely displays both mechanisms operating simultaneously, creating a true multi-scale reinforcement architecture. In contrast, sub-optimal formulations showed nanoparticle agglomerations that acted as stress concentrators under cyclic loading, explaining their intermediate fatigue performance despite high static strength. Full article

An in-line process analytical technology that measures drag force exerted by wet mass in a high-shear granulator on a thin cylindrical probe enabled real-time identification of distinct stages in high-shear wet granulation of acetaminophen. The technology known as Lenterra in-line rheometer outputs two parameters, the mean force pulse magnitude (MFPM) and the coefficient of variation of force pulse magnitude (CVFPM), that characterize granule densification and size uniformity in real time, providing a process fingerprint. The MFPM and CVFPM evolutions measured during granulation of acetaminophen formulations for varied amounts of added water were compared with the results of particle size distribution (PSD) analysis of the powder released after granulation and with the tablet dissolution tests. The comparison demonstrated a correlation between salient features of the MFPM and CVFPM evolutions and particle size distributions for different water amounts. Based on the measured process fingerprints, it was possible to identify the water amount optimal for best granulation output. In addition, MFPM and CVFPM evolutions allowed for the prediction of a granulation endpoint. The results indicate that in-line rheometry can be a useful tool for formulation development and scale-up of high-shear wet granulation processes. Full article

This study examines the compressive behavior and analytical modelling of natural and rubberized concretes (RuC) confined with low-cost glass chopped-strand mat (GCSM) jackets. A total of forty-two cylindrical specimens were tested under axial compression to assess the influence of rubber particle size, confinement configuration, and the number of GCSM layers. The RuC mixes were prepared by replacing 20% of fine aggregate by volume with crumb rubber of two size fractions: coarse (2.0 mm, retained on #10 sieve) and fine (0.425 mm, retained on #40 sieve). Both full- and strip-wrapping schemes were applied using two, four, and six layers of GCSM. The results demonstrated that GCSM jackets significantly enhanced the mechanical performance of both NAC and RuC specimens. Full wrapping provided the highest confinement efficiency, increasing compressive strength by up to 115% for NAC and 90% for RuC, while the ultimate axial strain increased by more than 1300% compared with unconfined specimens. Strip wrapping also improved performance, producing strength gains of 25–45% and strain increases of 250–500%. Analytical stress–strain models were developed through regression analysis, showing strong correlation with the experimental results (R² = 0.80–0.99). The proposed GCSM jacket system demonstrates high potential as a sustainable and economical alternative for strengthening and retrofitting rubberized concretes, offering improved ductility and energy absorption while supporting circular material utilization. It is noted that the confinement ratio, size of rubberized aggregates, and their percentage replacement of rubberized aggregates should be consistent with the values used in this work in order to use the proposed analytical expressions. Full article

High-velocity fluid flow in porous media frequently exhibits non-Darcy behavior, where inertial losses lead to nonlinear pressure gradient velocity behavior. Predicting the Forchheimer coefficient β remains challenging because β varies sensitively with pore geometry and is often not constrained by porosity and permeability alone. This study develops a structure-based method to estimate β using intrinsic descriptors obtained from the Darcy regime flow characterization and image-based geometry analysis. A set of two-dimensional granular porous media was generated with controlled variations in porosity, particle size distribution, and grain size variability. Single phase simulations are simulated with a body-force multiple-relaxation-time lattice Boltzmann method. The transition from Darcy flow to non-Darcy flow is identified from the velocity and pressure gradient response, and β is determined by fitting the inertial flow regime. Two tortuosity responses were observed. In uniform media, hydraulic tortuosity remained nearly constant in the Darcy regime and then gradually decreased. In disordered media, hydraulic tortuosity first increased with the onset of recirculation and then decreased as dominant flow paths became stable. Based on these results, a dimensionless inertial factor was correlated with porosity, intrinsic hydraulic tortuosity, and a pore structure index derived from specific surface area and hydraulic pore size. The resulting model predicts β from permeability and structural descriptors. The resulting correlation provides β estimates from Darcy permeability and geometry descriptors. Validation with quasi-two-dimensional microfluidic pillar array data showed that the model captured both the magnitude and relative ordering of β for the tested geometries. The proposed framework should be regarded as a proof of concept for idealized granular porous media and quasi-two-dimensional structured systems. Full article

Calculation of heat transfer in granular materials is an important task for many applications, from thermal management in electronics to exploring celestial soils. Usually, an effective thermal-conductivity model is employed to predict heat flux in unstructured granular media, such as a packed bed. However, a more advanced approach, the discrete element method (DEM), can capture the complex effects of mechanical loading and material mixtures on thermal transport coefficients, which traditional models struggle with. Pivotal for this approach is knowing the heat transfer coefficient between two adjacent particles. Currently, in most DEM-capable software, only particles in direct surface contact are considered to have non-zero heat conduction. We propose considering particles that are close to each other but don’t have a contact area with a non-zero surface area. We perform numerical modeling of the conductive heat transfer coefficient between equal spherical particles separated by media, assuming the fluid’s thermal conductivity is at least an order of magnitude lower. We use numerical solutions of differential equations to account for both thermal resistance within particles and through the gap between them. We found a simple generalized correlation for the heat transfer coefficient between particles and a general formula for the angular distribution of heat flux density across the particle surface. By employing a non-dimensional approach, the obtained formulas are constructed using non-dimensional parameters: the ratio of the particle’s thermal conductivity to that of the medium, and the ratio of the gap width between particles to their radius. The resulting formula is simple and convenient for DEM heat transfer calculations in packed and fluidized beds. Full article