Search Results (53)

This study presents a comprehensive smoothed particle hydrodynamics (SPH) framework developed to investigate the thermomechanical response and failure behavior of cylindrical 18650-type lithium-ion battery cans under explosion conditions. The model captures the coupled evolution of gas pressure, temperature, and particle dynamics, as well as the resulting deformation and fracture of the metallic enclosure. Parametric analyses were conducted to evaluate the influence of the internal gas domain geometry, can wall thickness, and initial pressure on the structural response, along with the subsequent post-explosion interaction between the escaping gas and external protective coverage. The results demonstrate the strong dependence of failure initiation on gas confinement geometry and highlight the existence of transient thermodynamic asymmetries within the gas domain that govern the impulse transferred to the can wall. The proposed modeling approach provides a physically consistent means of reproducing the key stages of battery explosion—from internal pressurization to external gas impact—and offers valuable insights for designing safer and more resilient energy storage enclosures. Full article

The transition to electric mobility has intensified efforts to develop battery technologies that are not only high-performing but also environmentally sustainable. A critical element in battery system design is the structural housing, which must provide effective impact protection to ensure passenger safety and prevent catastrophic failures. This study examines the impact response of an innovative sheet molding compound (SMC) composite battery housing, manufactured from an Elium resin modified with Martinal ATH matrix, reinforced with glass fibers, that combines fire resistance and recyclability, unlike conventional thermoset and metallic housings. The material was characterized through standardized mechanical tests, and its impact performance was evaluated via drop-weight experiments on plates and a full-scale housing. The impact tests were conducted at varying energy levels to induce barely visible impact damage (BVID) and visible impact damage (VID). A finite element model was developed in LS-DYNA using the experimentally derived material properties and was validated against the impact tests. Parametric simulations of ground and pole collisions revealed the critical velocity thresholds at which housing deformation begins to affect the first battery cells, while lower-energy impacts were absorbed without compromising the pack. The study provides one of the first combined experimental and numerical assessments of Elium SMC in battery enclosures, emphasizing its potential as a sustainable alternative for next-generation battery systems for transport applications. Full article

To meet safety regulations in underground coal mines, wireless power transfer (WPT) systems must house both the transmitter and receiver within explosion-proof enclosures. However, eddy currents induced on the surfaces of these non-ferromagnetic metal enclosures significantly hinder magnetic flux coupling, thereby reducing transmission efficiency. This paper proposes a slotting technique applied to explosion-proof enclosures to suppress eddy currents, along with the integration of magnetic flux focusing materials into the coils to enhance coupling. Simulations were conducted to compare three system configurations: (i) a WPT system without enclosures, (ii) a system with solid (unslotted) enclosures, and (iii) a system with slotted enclosures. The results show that solid enclosures reduce efficiency to nearly zero, whereas slotted enclosures restore efficiency to 90% of the baseline system without enclosures. Joule heating remains low in the slotted explosion-proof enclosures, with energy losses of 2.552 J for the transmitter enclosure and 2.578 J for the receiver enclosure. A conservative first-order estimation confirms that the corresponding temperature rise in the enclosure surfaces remains below 50 °C, which is well within the 150 °C limit stipulated by the Chinese National Standard GB 3836.1-2021 (Explosive Atmospheres—Part 1: Equipment General Requirements). These findings confirm effective eddy current suppression and efficiency recovery without compromising explosion-proof safety. The core innovation of this work lies not merely in the physical slotting approach, but in the development of a precise equivalent circuit model that fully incorporates all mutual inductance components representing eddy current effects in non-ferromagnetic explosion-proof enclosures, and its integration into the overall MCR-WPT system circuit. Full article

A lead–gold rougher concentrate was studied to investigate the efficiency of mineral processing. Using process mineralogy as the guiding theory, mineralogical parameters such as chemical composition, mineral composition, mineral particle size, and symbiotic association between minerals were studied in detail. A systematic lead flotation testwork program was carried out to obtain the optimal flotation and separation conditions, and the products obtained were analyzed. The results show that the concentrate contains a wide variety of minerals with complex material composition, and the lead mineral was mainly galena with a relative content of 3.43% and a particle size −37 μm accounting for 94.72%, while the gold minerals were dominated by electrum. The grades of gold, silver, and lead in the balland obtained through the flotation closed-circuit test were 512.10 g/t, 1632.80 g/t, and 40.38%, and the recoveries were 70.65%, 73.86%, and 75.37%, respectively. The gold lost in the flotation tailings was mainly dominated by gold encapsulated in metal sulfide (accounting for 55.67%), and the lead lost was mainly in gangue and metal oxides (accounting for 62.72%). Full article

Practical applications such as solar power energy systems, electronic cooling, and the convective drying of vented enclosures require continuous developments to enhance fluid and heat flow. Numerous studies have investigated the enhancement of heat transfer in L-formed vented cavities by inserting heat-generating components, filling the cavity with nanofluids, providing an inner rotating cylinder and a phase-change packed system, etc. Contemporary work has examined the thermal performance of L-shaped porous vented enclosures, which can be augmented by using metal foam, using nanofluids as a saturated fluid, and increasing the wall surface area by corrugating the cavity’s heating wall. These features are not discussed in published articles, and their exploration can be considered a novelty point in this work. In this study, a vented cavity was occupied by a copper metal foam with $PPI=10$ and saturated with a copper–water nanofluid. The cavity walls were well insulated except for the left wall, which was kept at a hot isothermal temperature and was either non-corrugated or corrugated with rectangular waves. The Darcy–Brinkman–Forchheimer model and local thermal non-equilibrium models were adopted in momentum and energy-governing equations and solved numerically by utilizing commercial software. The influences of various effective parameters, including the Reynolds number ($20\le Re\le 1000$), the nanoparticle volume fraction ($0\%\le \phi \le 20\%$), the inflow and outflow vent aspect ratios ($0.1\le D/H\le 0.4$), the rectangular wave corrugation number ($N=5$ and $N=10$), and the corrugation dimension ratio ($CR=1$ and $CR=0.5$) were determined. The results indicate that the flow field and heat transfer were affected mainly by variations in $Re$, $D/H$, and $\phi$ for a non-corrugated left wall; they were additionally influenced by $N$ and $CR$ when the wall was corrugated. The fluid- and solid-phase temperatures of the metal foam increased with an increase in $Re$ and $D/H$. The fluid-phase Nusselt number near the hot left sidewall increased with an increase in $\phi$ by $\left(25–60\right)\%$, while the solid-phase Nusselt number decreased by $\left(10–30\right)\%$, and these numbers rose by around $3.5$ times when the Reynolds number increased from $20$ to $1000$. For the corrugated hot wall, the Nusselt numbers of the two metal foam phases increased with an increase in $Re$ and decreased with an increase in $D/H$, $CR$, or $N$ by $10\%$, $19\%$, and $37\%$. The original aspect of this study is its use of a thermal, non-equilibrium, nanofluid-saturated metal foam in a corrugated L-shaped vented cavity. We aimed to investigate the thermal performance of this system in order to reinforce the viability of applying this material in thermal engineering systems. Full article

The electric energy metering box serves as a crucial node in power grid operations, offering essential protection for key components in the distribution network, such as smart meters, data acquisition terminals, and circuit breakers, thereby ensuring their safe and reliable operation. However, the non-metallic housings of these boxes are susceptible to aging under environmental stress, which can result in diminished flame-retardant properties and an increased risk of fire. Currently, there is a lack of rapid and accurate methods for assessing the fire resistance of non-metallic metering box enclosures. In this study, laser-induced breakdown spectroscopy (LIBS), which enables fast, multi-element, and non-contact analysis, was utilized to develop an effective assessment approach. Thermal aging experiments were conducted to systematically investigate the degradation patterns and mechanisms underlying the reduced flame-retardant performance of sheet molding compound (SMC), a representative non-metallic material used in metering box enclosures. The results showed that the intensity ratio of aluminum ionic spectral lines is highly correlated with the flame-retardant grade, serving as an effective performance indicator. On this basis, a one-dimensional convolutional neural network (1D-CNN) model was developed utilizing LIBS data, which achieved over 92% prediction accuracy for different flame-retardant grades on the test set and demonstrated high recognition accuracy for previously unseen samples. This method offers significant potential for rapid, on-site evaluation of flame-retardant grades of non-metallic electric energy metering boxes, thereby supporting the safe and reliable operation of power systems. Full article

This study investigates natural convection of liquid metal in an annular enclosure with a square cross-section using three-dimensional numerical simulations. Liquid metals, with low Prandtl numbers, exhibit oscillatory transitions at lower Rayleigh numbers than conventional fluids. While previous studies focused on full-circle domains where steady or irregular flows were observed, this work examines the effect of angular partitions on flow dynamics. The results reveal that periodic three-dimensional oscillatory flows arise in domains with specific angular sizes, such as quarter circles, whereas full-circle domains produce irregular or steady flows. Angular wave numbers vary spatially and temporally during transitional growth. The emergence of half-symmetric oscillatory modes highlights the role of symmetry constraints imposed by the geometry and boundary conditions. These transitions are closely tied to symmetry breaking and mode selection. A linear stability perspective helps clarify the critical factors that determine the transition type. These findings underscore that angular segmentation and periodic boundary conditions are essential for sustaining regular oscillatory convection. This study contributes to the understanding of symmetry-governed convection transitions in low-Prandtl-number fluids and has potential implications for industrial processes, such as semiconductor crystal growth, where flow uniformity and thermal stability are crucial. Full article

Defects in GIS can be effectively detected by detecting the partial discharge (PD). The common methods of detecting partial discharge are pulse current, ultrasonic and UHF (ultra-high frequency). However, the results of different methods may be different due to the different physical quantities detected. It is important to research the differences between the PD detection methods for the PD detection and analysis. In this study, we designed metal protrusion defects in GIS, including protrusion on the conductor and enclosure. Then, we detected the PD of defects using pulse current, UHF and ultrasonic methods at the same time. The PRPD patterns, maximum discharge amplitude of different defects and PD inception voltage (PDIV) detected by the three methods were analyzed. The PRPD patterns and discharge amplitude of the different methods were very similar to each other, but the PDIVs were different. It can be concluded that the process from the PD inception to breakdown can be divided into four sections based on the PRPD and the maximum discharge amplitude. The similarity between the three methods is because their signals are all related to the pulse current during the PD process, and differences in their PDIVs are caused by the differences in sensitivity. The sensitivity of the pulse current is the lowest among the three methods due to its poor anti-jamming capability. The sensitivity of UHF is higher, and that of ultrasonic is the highest. Full article

The building sector significantly contributes to global energy consumption and carbon emissions, primarily due to the extensive use of carbon-intensive materials such as concrete and steel. Mass timber construction, particularly using cross-laminated timber (CLT), offers a promising low-carbon alternative. This study aims to calculate the embodied carbon emissions and biogenic carbon storage of a CLT-based affordable housing project, 340+ Dixwell in New Haven, Connecticut. This project was designed using a honeycomb structural system, where mass timber floors and roofs are supported by mass timber-bearing walls. The authors are not aware of a prior study that has evaluated the life cycle impacts of honeycomb mass timber construction while considering Timber Use Intensity (TUI). Unlike traditional post-and-beam systems, the honeycomb design uses nearly twice the amount of timber, resulting in higher carbon sequestration. This makes the study significant from a sustainability perspective. This study follows International Standard Organization (ISO) standards 14044, 21930, and 21931 and reports the results for both lifecycle stages A1–A3 and A1–A5. The analysis covers key building components, including the substructure, superstructure, and enclosure, with timber, concrete, metals, glass, and insulation as the materials assessed. Material quantities were extracted using Autodesk Revit^®, and the life cycle assessment (LCA) was evaluated using One Click LCA (2015)^®. The A1 to A3 stage results of this honeycomb building revealed that, compared to conventional mass timber housing structures such as Adohi Hall and Heartwood, it demonstrates the lowest embodiedf carbon emissions and the highest biogenic carbon storage per square foot. This outcome is largely influenced by its higher Timber Use Intensity (TUI). Similarly, the A1-A5 findings indicate that the embodied carbon emissions of this honeycomb construction are 40% lower than the median value for other multi-family residential buildings, as assessed using the Carbon Leadership Forum (CLF) Embodied Carbon Emissions Benchmark Study of various buildings. Moreover, the biogenic carbon storage per square foot of this building is 60% higher than the average biogenic carbon storage of reference mass timber construction types. Full article

Electrolytic plasma polishing technology is widely used in medical devices, aerospace, nuclear industry, marine engineering, and other equipment manufacturing fields, owing to its advantages of shape adaptability, high efficiency, good precision, environmental protection, and non-contact polishing. However, the lack of in-depth research on the material removal mechanism of the electrolytic plasma polishing process severely restricts the regulation of the process parameters and polishing effect, leading to optimization and improvement by experimental methods. Firstly, the formation mechanism of passivation film was revealed based on an analysis of the surface morphology and chemical composition of stainless steel. Subsequently, the dissolution mechanism of the passivation film was proposed by analyzing the change in the valence state of the main metal elements on the surface. In addition, the surface enclosure leveling mechanism of electrolytic plasma polishing (EPP) for stainless steel was proposed based on a material removal mechanism model combined with experimental test methods. The results show that EPP significantly reduces the surface roughness of stainless steel, with Ra being reduced from 0.445 µm to 0.070 µm. Metal elements on the anode surface undergo electrochemical oxidation reactions with reactive substances generated by the gas layer discharge, resulting in the formation of passivation layers of metal oxides and hydroxides. The passivation layer complexes with solvent molecules in the energetic plasma state of the gas layer with SO₄²⁻ ions, forming complexes that enter the electrolyte. The dynamic balance between the formation and dissolution of the passivation film is the key to achieving a flat surface. This study provides theoretical guidance and technical support for the EPP of stainless steel. Full article

Standards describing the test procedures recommended to investigate the shielding effectiveness of enclosures have two major issues: they generally prescribe the assessment of the electromagnetic field of empty cavities, and they do not deal with very small enclosures. However, the dimensions of some very common shielded apparatus are smaller than those considered in the standards and the electromagnetic field distribution inside the shielded structure is strongly affected by the enclosure content. In this paper, both issues have been investigated for two components commonly used in medium voltage/low voltage (MV/LV) substations: a mini personal computer used to store, process, and transmit relevant data on the status of the electric network, with these aspects being essential in smart grids, and an electronic relay which is ubiquitous in MV/LV substations. Both components are partially contained in a metallic enclosure which provides a certain amount of electromagnetic shielding against external interferences. It is observed that an electrostatic discharge may cause a failure and/or a loss of data, requiring an improvement of shielding characteristics or a wise choice of the positions where the most sensitive devices are installed inside the enclosure. Since the dimensions of very small enclosures, fully occupied by their internal components, do not allow for the insertion of sensors inside the protected volume, numerical analysis is considered as the only way for the appraisal of the effects induced by a typical source of interference, such as an electrostatic discharge. Full article

This study investigates the construction methodology of large-span cable-stayed tensioned metal thin-sheet structures, introducing the “integrated enclosure and load-bearing” design concept. By applying in-plane prestress, the out-of-plane stiffness of the metal thin sheet is effectively enhanced, enabling it to simultaneously serve as an enclosure and a load-bearing component. Through experimental studies and finite element analysis, the study systematically examines the effects of various construction methods on internal forces and displacements. The tensioning of back cables is identified as the safest and most efficient construction method. Subsequently, through simulations of a three-span structure and tensioning forming tests, the research examines displacement, stress, and cable force distribution patterns, demonstrating that increases in the tensioning level result in corresponding increases in sheet surface stress, cable forces, and displacements. The structure exhibits a concave middle section, upward curvatures at both ends, and outward-leaning end columns. Structural members with lower cable forces show minimal impact on displacement and are therefore identified as suitable targets for design optimization. This study offers a theoretical foundation and practical engineering insights to guide the optimization of design and construction for cable-stayed tensioned metal thin-sheet structures. Full article

Understanding the effects of landscape greening pest control modes (LGPCMs) on carbon storage and soil physicochemical properties is crucial for promoting the sustainable development of urban landscape greening. Climate change and green development have led to increased landscape pest occurrences. However, the impacts of different LGPCMs on carbon storage and soil properties remain unclear. We examined six typical LGPCMs employed in Beijing, China: chemical control (HXFZ), enclosure (WH), light trapping (DGYS), biological agent application (SWYJ), natural enemy release (SFTD), and trap hanging (XGYBQ). Field surveys and laboratory experiments were conducted to analyze their effects on carbon storage and soil physicochemical properties, and their interrelationships. The main results were as follows: (1) Different LGPCMs significantly affected carbon storage in the tree and soil layers (p < 0.05), but not in the shrub and herb layers (p > 0.05). Carbon storage composition across all modes followed the following order: tree layer (64.19%–93.52%) > soil layer > shrub layer > herb layer. HXFZ exhibited the highest tree layer carbon storage (95.82 t/hm²) but the lowest soil layer carbon storage (6.48 t/hm²), while DGYS performed best in the soil, herb, and shrub layers. (2) LGPCMs significantly influenced soil bulk density (SBD), clay (SC), silt particle (SSP), sand (SS), pH, organic carbon (OC), total nitrogen (TN), and heavy metal content (lead (Pb), cadmium (Cd), mercury (Hg)). WH had the highest TN (1.37 g/kg), TP (0.84 g/kg), SC (10.71%) and SSP (42.14%); HXFZ had the highest Cd (8.98 mg/kg), but lowest OC and Pb. DGYS had the highest OC and Hg, and the lowest Cd, SC, and TP. Under different LGPCMs, the heavy metal content in soil ranked as follows: Pb > Cd > Hg. (3) There were significant differences in the relationship between carbon storage and soil physicochemical properties under different LGPCMs. A significant positive correlation was observed between the soil layer carbon storage, TN, and OC, while significant negative correlations were noted between SS and SC as well as SSP. Under SFTD, the tree layer carbon storage showed a negative correlation with Cd, while under DGYS, it correlated negatively with pH and Hg. In summary, While HXFZ increased the short-term tree layer carbon storage, it reduced carbon storage in the other layers and damaged soil structure. Conversely, WH and DGYS better supported carbon sequestration and soil protection, offering more sustainable control strategies. We recommend developing integrated pest management focusing on green control methods, optimizing tree species selection, and enhancing plant and soil conservation management. These research results can provide scientific guidance for collaborative implementation of pest control and carbon sequestration in sustainable landscaping. Full article

This paper describes a numerically efficient method for optimizing the high power transfer efficiency (PTE) of a resonant cavity-based Wireless Power Transfer (WPT) system for the wireless charging of smart clothing. The WPT system under study unitizes a carbon steel closet intended to store smart clothing overnight as a resonant cavity. The WPT system is designed to operate at 865.5 MHz; however, the operating frequency can be adjusted over a wide range. The main reason behind choosing a resonant cavity-based WPT system is that it has several advantages over the competitive WPT methods. Specifically, in contrast to its Far-field Power Transfer (FPT) and Inductive Power Transfer (IPT) counterparts, resonant cavity-based WPTs do not exhibit path loss and significant PTE sensitivity to the distance between the Tx and Rx coils and misalignment, respectively. The non-uniformity of the fields within the closet is addressed by using an optimized Yagi-like transmitting antenna with an additional element affecting the waveguide mode phases. The changes in the mode phases increase the volume inside the cavity, where the PTE values are higher than 50% (the high PTE region). In the present study, the model decomposition method is adapted to substantially accelerate the process of finding the optimal WPT system parameters. Additionally, the decomposition method explains the mechanism responsible for extending the high PTE region. The generalized scattering matrices are computed using the full-wave simulator Ansys HFSS for three sub-models. Then, the calculated S matrices are combined to evaluate the system’s PTE. The decomposition method is validated against full-wave simulations of the original WPT system’s model for several different parameter value combinations. The simulated results obtained for a sub-optimal model are experimentally verified by measuring the PTE of a real-life closet-based WPT system. The measured and calculated results are found to be in close agreement with the maximum measured PTE, as high as 60%. Full article

A flat-plate unglazed solar water heater (SWH) with a polymer thermal absorber was developed and experimented with. Polymer thermal absorbers could be a viable alternative to metal thermal absorbers for SWH systems. The performance of this polymer SWH system was measured based on inlet and outlet water temperature, water flow rate, ambient air temperature and solar irradiance. The polymer thermal absorbers were hollow Polyvinyl Chloride (PVC) tubes with a 20 mm external diameter and 3 mm thickness and were painted black to enhance radiation absorption. The pipes are arranged in a rectangular spiral inward–outward alternating-flow (RSioaf) pattern. The collector pipes were placed in a 1 m × 1 m enclosure with bottom insulation and a reflective surface for maximized radiation absorption. Water circulated through a closed loop with an uninsulated 16 L storage tank, driven by a pump and controlled by two valves to maintain a mass flow rate of 0.0031 to 0.0034 kg·s⁻¹. The test was conducted under a partially clouded sky from 9 a.m. to 5 p.m., with solar irradiance between 105 and 1003 W·m⁻² and an ambient air temperature of 27–36 °C. This SWH system produced outlet hot water at 65 °C by midday and maintained the storage temperature at 63 °C until the end of the test period. Photothermal energy conversion was recorded, showing a maximum value of 23%. Results indicate that a flat-plate solar water heater with a polymer thermal absorber in an RSioaf design can be an effective alternative to an SWH with a metal thermal absorber. Its performance can be improved with glazing and optimized tube sizing. Full article