Search Results (97)

Oblique detonation engines have been proposed for hypersonic propulsion because detonation-based heat addition can, in principle, provide rapid energy release with reduced total-pressure penalties. We investigate non-premixed injection/mixing of an RP-3 aviation-kerosene surrogate in a constrained supersonic channel and its impact on oblique-detonation initiation, stabilization, and static pressure gain. Numerical simulations are performed for a Mach 8 inflow representative of a 30 km altitude condition using an OpenFOAM v7-based reacting-flow solver. We analyze the pressure-gain process following detonation onset, quantify the effects of the inducer-ramp angle, and qualitatively assess the predicted initiation/stabilization trends against direct-connect hot-fire experiments. The results show that non-premixed injection into a supersonic crossflow yields limited mixing over the available mixing length and results in a strongly stratified inflow to the combustor. In the constrained passage, a train of reflected shocks forms and progressively reduces the total-pressure recovery factor along the mixing section, which asymptotically approaches ~0.49. In the combustor, the inducer-ramp angle controls whether and how a stabilized oblique detonation can be established. For a 25° ramp, no self-sustained ODW is obtained under the present conditions, whereas stabilized ODWs are observed for 30° and 35° ramps, exhibiting abrupt and smooth topologies, respectively. These initiation thresholds and stabilized morphologies show qualitative consistency with the direct-connect observations. Due to fuel stratification, pressure gain varies among streamlines but consistently follows a “primary compression–plateau–secondary pressure rise” sequence; the secondary stage contributes approximately 17.54–27.98% of the static pressure rise. Full article

The peridynamic (PD) method has been widely utilized in the numerical modelling of ice–structure interactions due to its capability to naturally capture material failure and fracture evolution. PD formulations can be categorized into bond-based and state-based models. While the bond-based model offers computational simplicity, it inherently restricts Poisson’s ratio to 1/4 in three-dimensional (3D) simulations and 1/3 in two-dimensional (2D) simulations. In contrast, the state-based model allows for arbitrary Poisson’s ratios, which is essential for accurately modelling ice mechanics, as Poisson’s ratio of ice commonly exceeds 0.33 and can reach up to 0.42. This study employs the PD method coupled with the discrete energy release rate criterion to analyze the influence of Poisson’s ratio on ice failure mechanisms and ice-induced loads in two typical scenarios: cylindrical impact on an ice disc and ice–structure interaction with a propeller blade. The benchmark compression test yielded computed Poisson’s ratios of 0.215, 0.258, 0.333, and 0.401 for prescribed values of 0.2, 0.25, 0.33, and 0.40, corresponding to relative errors of 7.5%, 3.2%, 1.02%, and 0.38%, respectively. And the fracture simulations indicate that variations in Poisson’s ratio affects ice fracture patterns and load distributions, underscoring the limitations of the bond-based PD model in accurately representing ice–structure interactions. These findings highlight the necessity of adopting state-based PD formulations for improved numerical predictions of ice-induced mechanical responses. Full article

This study integrates physical similarity experiments with numerical simulations to examine how overburden lithology influences roof caving behavior and stress field evolution at a longwall mining face. The results demonstrate that overburden strength significantly governs the timing, extent, and periodicity of roof caving, while also strongly affecting the evolution of mining-induced stress. As lithological strength increases, both damage and displacement within the overburden strata decrease. High-strength roofs exhibit larger caving step distances and longer stress accumulation periods. In contrast, low-strength roofs enter the plastic deformation stage earlier, leading to shorter caving step distances, more frequent caving events, and a wider caving range. During coal seam extraction, roof deformation is accompanied by stress concentration and release, which are processes that are closely associated with dynamic disasters. Due to their higher elastic modulus and compressive strength, high-strength rock strata can accumulate greater elastic strain energy prior to failure. Once instability occurs, the rapid release of stored energy leads to intense stress redistribution and dynamic loading. As lithological strength increases, the stress concentration shell evolves from an arch-shaped structure to a flatter configuration. This transition results in higher internal stress levels and stronger stress concentration, thereby increasing the risk of dynamic disasters such as impact instability. Therefore, maintaining the stability of the stress concentration shell and preventing its migration into deeper strata are essential for ensuring surrounding rock stability and safe mining operations. Full article

While membrane technologies are critical for preventing microplastics (MPs) release into aquatic ecosystems, MPs-induced fouling remains a persistent bottleneck, necessitating energy-intensive cleaning strategies that introduce their own environmental burdens. This study presents a systematic life cycle assessment (LCA) of fouling mitigation strategies, rigorously comparing hydraulic forward flushing and nitrogen (N₂) gas scouring across both unmodified and plasma-modified (acrylic acid, cyclopropylamine, and hexamethyldisiloxane) polysulfone membranes. Results reveal a stark divergence between operational performance and environmental sustainability. Baseline operations and the hydraulic flushing of unmodified membranes have environmentally costly global warming potential (GWP) ~150 kg CO₂-eq/m³), driven primarily by high electricity consumption and frequent membrane replacement. Conversely, cyclopropylamine (CPAm) plasma-modified membranes emerging as the optimal strategy, reducing global warming potential to 68 kg CO₂-eq/m³ and cutting electricity demand by 44% through superior fouling resistance. Crucially, the study uncovers a significant trade-off regarding gas scouring: While it achieves the highest technical performance (minimal flux decline of 0.33% h⁻¹), the upstream burdens of N₂ supply increased environmental impacts by over 100% across all categories. These findings challenge the assumption that maximum fouling control equates to sustainability, suggesting that surface engineering via plasma modification, rather than aggressive physical cleaning, offers the most viable pathway for sustainable MPs remediation. Full article

Spatial efficiency drives the adoption of integrated station–bridge structures in maglev transit, yet the rigid coupling between track and station poses inherent challenges to vibration serviceability. This study isolates the impact of support constraints, specifically contrasting rigid connections with pinned supports, on the dynamic performance of a five-story maglev station. Using a unified, high-fidelity 3D coupled model that incorporates electromagnetic suspension nonlinearity, we evaluated structural responses under train speeds of 60–120 km/h. Simulations identify a critical operational threshold: while the waiting hall remains compliant with standard comfort criteria (DIN 4150-3), the platform floor exceeds the 1.5% g acceleration limit during dual-track operations at speeds ≥ 100 km/h. Beyond standard safety checks, the main scientific innovation of this study is revealing the mechanical transmission paths of structure-borne vibrations at the track-frame interface. The results demonstrate that rigid connections create full mechanical coupling, directly passing train-induced bending moments into the station frame. Conversely, pinned supports release the rotational degrees of freedom, which physically cuts off the primary energy transmission route. By explaining this structural decoupling mechanism, this work moves beyond a specific engineering case study to provide a fundamental theoretical framework for vibration control in complex maglev hubs. Full article

Neuroplacentology is an emerging field of research supporting that the placenta actively contributes to the fetal brain development through the release of bioactive molecules. Recent angiogenesis-focused data showed that prenatal alcohol exposure (PAE) disrupts inter-organ gene expression between the placenta and fetal cortex. The present study aimed to perform the first comprehensive and untargeted analysis of a murine placenta–cortex transcriptomic database of PAE. Gene lists from a recently NCBI-deposited PAE Placenta–Cortex transcriptomic database were analyzed using g:Profiler for unbiased functional profiling querying Gene Ontology, KEGG, and Reactome databases. Genes intersecting with cell–cell communication terms were submitted to STRING and ShinyGO analyses to identify enriched protein–protein interactions and pathways. Several ligand or receptor candidates were then validated by Western blot. g:Profiler revealed 21 enriched GO functional maps, seven KEGG pathways, and six Reactome pathways, of which 11 were related to cell-to-cell communication. STRING analysis exhibited substantial protein–protein interaction enrichments supporting that proteins belonging to the functional maps and pathways are biologically connected. Notably, 38 ligands or receptors from endocrine families including angiotensinogen, leptin, somatostatin, or PACAP were identified. Western blot analysis of protein candidates showed different validation patterns. In particular, the PACAP receptor family confirmed transcriptomic findings and revealed sex-dependent PAE-impacted expression profiles. The present study indicates that PAE is associated with alterations in the transcriptomic placenta–cortex expression profile, including changes in the expression ratios of several ligands and/or receptors implicated in key physiological pathways such as energy balance, vascular development, and neurogenesis. These transcriptomic associations suggest that altered placenta–fetal brain signaling at the gene expression level may be involved in alcohol-induced neurodevelopmental disorders, highlighting the need for future functional validation studies. Full article

Under the influence of engineering disturbances, the loading rate of surrounding rock is in a state of continuous adjustment. This study conducts experimental investigations on the mechanical response characteristics under different strain rates (10⁻⁵ s⁻¹, 10⁻⁴ s⁻¹, and 10⁻³ s⁻¹). During the uniaxial loading process of coal–rock composite specimens, multi-parameter monitoring was implemented, and a systematic study was carried out on the ring-down count induced by microcracks, the energy values of acoustic emission (AE) events, the stage-dependent strain characteristics on the specimen surface, and the surface temperature variation characteristics. Additionally, the stress–strain curve characteristics under different strain rates were comparatively analyzed in stages. The loading process of the coal–rock composite specimens was reproduced using the Particle Flow Code (PFC3D 6.0) simulation software. The simulation results indicate that the stress–strain results obtained from the simulation are in good agreement with the laboratory test results; based on these simulation results, the energy accumulation and dissipation characteristics of the coal–rock composite specimens under the influence of strain rate were revealed. Furthermore, a microscopic damage model considering strain rate was constructed based on the Weibull probability statistics theory. The results show that strain rate has a significant impact on the strength, elastic modulus, and failure mode of the coal–rock composite specimens. At low strain rates, the specimens exhibit obvious progressive failure characteristics and strain localization phenomena, while at higher strain rates, they show brittle sudden failure characteristics. Meanwhile, the thermal imaging results reveal that at high strain rates, the overall temperature rise in the composite specimens is rapid, whereas at low strain rates, the overall temperature rise is slow—but the temperature rise in the coal portion is faster than that in the rock portion. The peak temperature at high strain rates is approximately 2 °C higher than that at low strain rates. The PFC simulation results demonstrate that the larger the strain rate, the faster the growth rate of plastic energy in the post-peak stage and the faster the release rate of elastic energy. Full article

During mining, rock failure and water infiltration induce variations in deformation, energy release, electrical conductivity, and water content. Their response laws underpin water-preserving mining optimization, environmental impact mitigation, and mining area sustainability, while facilitating the prediction of stratum instability and water migration. In this study, uniaxial compression experiments were conducted on sandstone with different water saturations, during which the responses of strain, acoustic emission energy, and electrical resistivity were monitored. The temporal characteristics of the rock’s multi-parameter responses were analyzed, and the influence of water content on precursor information of rock failure was revealed. Multi-parameter response equations for rocks under loading, incorporating the effect of water saturation, were established. A segmented variable-weight-integrated damage constitutive model for water-bearing rocks was developed based on the multi-parameter responses. The findings showed that the temporal characteristics of multi-parameter coupling responses can reflect the damage evolution and pore water migration during the instability and failure process of water-bearing rocks. As water saturation increased from 0% to 100%, the rock exhibited the following variations: peak stress decreased by 38.49%, strain at peak stress increased by 8.79%, elastic modulus decreased by 41.58%, cumulative acoustic emission energy drops by 93.23%, and initial electrical resistivity plummets by 98.02%. Compared with the theoretical stress–strain curves based on strain damage variables, cumulative acoustic emission energy damage variables, and electrical resistivity damage variables, the theoretical stress–strain curve based on the integrated damage variable shows better agreement with the measured curve, with the coefficient of determination exceeding 0.98. The research findings offer valuable insights into rock mass instability and groundwater migration, supporting water-preserving mining and sustainable mining area development. Full article

This study investigates the effects of anodizing and welding parameters on the microstructure and mechanical properties of laser-welded die-cast A356 aluminum alloy. The influence of different surface oxidation conditions, namely, no anodized film (NAF), single-sheet anodized film (SSAF), and double-sheet anodized films (DSAF), was assessed. The porosity, elemental distribution, and mechanical behavior was systematically analyzed. The results indicate that anodizing reduces the fusion zone (FZ) size by approximately 5%–15% and increases porosity, primarily due to the thermal-barrier effect, energy consumption during film decomposition, and hydrogen release. Welding speed and defocusing amount have a significant impact on heat input and melt-pool dynamics. Quantitative analysis revealed that lower welding speeds and positive defocusing amount increased the FZ size by 15% and porosity by 2%–5%. In contrast, optimized conditions (welding speed of 4 m/min and 0 mm defocus) enhanced gas evacuation and minimized pore formation. Elemental analysis showed that anodizing promoted Si enrichment and increased oxygen incorporation, with oxygen content rising by 10%–15%, from 0.78 wt% (NAF) to 1.31 wt% (DSAF). Microhardness testing revealed a reduction in heat-affected zone (HAZ) hardness due to thermal softening induced by anodizing, while FZ hardness peaked under optimized welding conditions, reaching a maximum value of 95.66 HV. Tensile testing indicated that anodized films enhance the yield strength (YS) of the fusion zone (FZ) but may reduce ductility. Under optimized welding conditions (4 m/min, 0 mm), the joints exhibited the best overall performance, achieving the YS of 125.28 ± 10.57 MPa, an ultimate tensile strength (UTS) of 193.18 ± 3.66 MPa, and an elongation of 3.46 ± 0.25%. These findings provide valuable insights for optimizing both anodizing and welding parameters to improve the mechanical properties of A356 joints. Full article

In this study, we propose a novel energetic structural material, HfZrTi(TaNbV)_x (x = 0.1, 0.3, 0.5, 0.7, 0.9, Ta:Nb: V = 1:1:1), to improve the ductility and toughness of the HfZrTi high-entropy alloy (HEAs). The transformation of the single-phase Hexagonal Close-Packed (HCP) HfZrTi-based alloy into a Body-Centered Cubic (BCC) phase HfZrTiTaNbV alloy can be achieved by tuning the concentration of Group VB β-stabilizing elements. The proposed alloy combines the insensitivity and excellent mechanical strength of conventional inert alloys with the ability to react with air under high-velocity impact for energy release. The mechanical properties and energy release characteristics of HZTX_x (H = Hf, Z = Zr, T = Ti, X = TaNbV) at various strain rates are systematically investigated, and comprehensive microstructural characterization is performed, establishing a clear structure–property relationship. Under high-rate loading, the rapid oxidation of reactive elements, such as Hf and Zr, with atmospheric oxygen releases substantial chemical energy, which can be further enhanced by an adiabatic temperature rise, inducing local thermal softening through adiabatic shear bands. This study elucidates the connection between the deformation response mechanism of HZTX_x under dynamic loading and the microstructure, providing crucial insights for advancing the application of high-entropy alloys in energetic systems. Full article

As an important technology to enhance nutrient use efficiency and reduce agricultural non-point source pollution, controlled-release fertilizers (CRFs) have been widely applied in modern agriculture. However, during packaging, transportation, and field application, CRF particles are prone to mechanical impacts, which can lead to particle fragmentation and damage to the controlled-release coating. This compromises the release kinetics, increases nutrient loss risk, and ultimately exacerbates environmental issues such as eutrophication. Currently, studies on the impact-induced fragmentation behavior of CRF particles remain limited, and there is an urgent need to investigate their fragmentation susceptibility mechanisms from the perspective of internal stress evolution. In this study, the mechanical properties of CRF particles were first experimentally determined to obtain essential parameters. A two-layer finite element model representing the coating and core structure of the particles was then constructed, and a fragmentation susceptibility index was proposed as the key evaluation criterion. The index, defined as the ratio of fractured volume to peak impact energy, reflects the efficiency of energy conversion at the critical moment of particle rupture (1–5). An explicit dynamic simulation framework incorporating multiple influencing factors—equivalent diameter, sphericity, impact material, velocity, and angle—was developed to analyze fragmentation behavior from the perspective of energy transformation. Based on the observed effects of these variables on fragmentation susceptibility, three regression models were developed using response surface methodology to quantitatively predict fragmentation susceptibility. Comparative analysis between the simulation and experimental results showed a fragmentation rate error range of 0–11.47%. The findings reveal the relationships between particle fragmentation modes and energy responses under various impact conditions. This research provides theoretical insights and technical guidance for optimizing the mechanical stability of CRFs and developing environmentally friendly fertilization strategies. Full article

The rapid growth of the human population and industrialization has intensified anthropogenic activities, leading to the release of various toxic chemicals into the environment, triggering significant risks to human health and ecosystem stability. One sustainable solution to remove toxic chemicals from various environmental matrices, such as water, air, and soil, is bioremediation, an approach utilizing biological agents. Microalgae, as the primary producers of the aquatic environment, offer a versatile bioremediation platform, where their metabolic processes break down and convert pollutants into less harmful substances, thereby mitigating the negative ecological impact. Besides the CO₂ sequestration potential, microalgae are a source of renewable energy and numerous high-value biomolecules. Additionally, microalgae can mitigate various toxic chemicals through biosorption, bioaccumulation, and biodegradation. These remediation strategies propose a sustainable and eco-friendly approach to address environmental pollution. This review evaluates the microalgal mitigation of major environmental contaminants—heavy metals, pharmaceuticals and personal care products (PPCPs), persistent organic pollutants (POPs), flue gases, microplastics, and nanoplastics—linking specific microalgae removal mechanisms to pollutant-induced cellular responses. Each section explicitly addresses the effects of these pollutants on microalgae, microalgal bioremediation potential, bioaccumulation process, the risks of trophic transfer, and biomagnification in the food web. Herein, we highlight the current status of the microalgae-based bioremediation prospects, pollutant-induced microalgal toxicity, bioaccumulation, and consequential biomagnification. The novelty of this review lies in integrating biomagnification risks with the bioremediation potential of microalgae, providing a comprehensive perspective not yet addressed in the existing literature. Finally, we identify major research gaps and outline prospective strategies to optimize microalgal bioremediation while minimizing the unintended trophic transfer risks. Full article

The decomposition of high-energy materials often releases large volumes of toxic fumes, contributing to environmental pollution. To reduce these emissions, eco-friendly formulations are being developed by modifying chemical composition or adding functional additives that enhance combustion and reduce toxic byproducts. Hydrogen peroxide (H₂O₂), acting as both an oxidizer and potential fuel, shows promise in lowering NO_x emissions. However, its impact on formulation stability must be assessed. This study examines the morphological and thermal behavior of an ammonium nitrate, fuel oil, and hydrogen peroxide (ANFOHP) formulation using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and thermal analysis based on thermogravimetry (TG) connected with differential scanning calorimetry (DSC) techniques. SEM showed that the fuel oil–hydrogen peroxide (FOHP) blend formed a thin film on ammonium nitrate prills without structural damage. XRD patterns indicated an intact crystalline structure. Moreover, FT-IR analysis performed both for fresh and 24-h stored samples evidenced no structural changes. In turn, TG/DSC revealed altered thermal behavior, with a new endothermic peak near 80 °C corresponding to the simultaneous evaporation of water and hydrogen peroxide from the ANFO surface, and reduced intensity of the main ANFO decomposition peak, indicating a shift in the thermal behavior induced by the FOHP blend. Full article

Coal mining can cause the rupture of the overlying strata, and the energy released by large-scale fractures can therefore induce earthquake disasters, which in turn can cause more secondary disasters. In the past 50 years, countless earthquakes induced by coal mining have been reported. In this paper, the main factors relating to the mining-induced seismicity, including the mechanical properties, geometry of the space, excavation advance, and excavation rate, are investigated using both experimental and numerical methods. The sensitivity of these factors behaves differently with regard to the stress distribution and failure mode. Space geometry and excavation advances have the highest impact on the surface settlement and the failure, while the excavation rate in practical engineering projects has the least impact on the failure mode. The numerical study coincides well with the experimental observation. The result indicates that the mechanical properties given by the geological survey report can be effectively used to assess the risk of mining-induced seismicity, and the proper adjustment of the tunnel geometry can largely reduce the surface settlement and improve the safety of mining. Full article

To address the challenges of prolonged current isolation times and high dependency on varistors in traditional flexible short-circuit fault isolation schemes for DC systems, this paper proposes a rapid fault isolation circuit design based on an adaptive solid-state circuit breaker (SSCB). By introducing an adaptive current-limiting branch topology, the proposed solution reduces the risk of system oscillations induced by current-limiting inductors during normal operation and minimizes steady-state losses in the breaker. Upon fault occurrence, the current-limiting inductor is automatically activated to effectively suppress the transient current rise rate. An energy dissipation circuit (EDC) featuring a resistor as the primary energy absorber and an auxiliary varistor (MOV) for voltage clamping, alongside a snubber circuit, provides an independent path for inductor energy release after faults. This design significantly alleviates the impact of MOV capacity constraints on the fault isolation process compared to traditional schemes where the MOV is the primary energy sink. The proposed topology employs a symmetrical bridge structure compatible with both pole-to-pole and pole-to-ground fault scenarios. Parameter optimization ensures the IGBT voltage withstand capability and energy dissipation efficiency. Simulation and experimental results demonstrate that this scheme achieves fault isolation within 0.1 ms, reduces the maximum fault current-to-rated current ratio to 5.8, and exhibits significantly shorter isolation times compared to conventional approaches. This provides an effective solution for segment switches and tie switches in millisecond-level self-healing systems for both low-voltage (LVDC, e.g., 750 V/1500 V DC) and medium-voltage (MVDC, e.g., 10–35 kV DC) smart DC distribution grids, particularly in applications demanding ultra-fast fault isolation such as data centers, electric vehicle (EV) fast-charging parks, and shipboard power systems. Full article