Search Results (4,435)

This article investigates three different rotor topologies of permanent magnet synchronous motors (PMSMs), namely the basic spoke-type permanent magnet rotor (BSPM), surface spoke-type permanent magnet rotor (SSPM), and interior spoke-type permanent magnet rotor (ISPM). A systematic comparison and analysis of their electromagnetic performance are conducted under no-load, rated-load, and overload conditions, with emphasis on key characteristics such as the flux density distribution, no-load back electromotive force (EMF), cogging torque, rated output torque, and overload potential. Furthermore, critical design indicators including torque density, required permanent magnet (PM) volume, and PM material utilization are thoroughly evaluated. The findings indicate that the SSPM exhibits a higher overload potential and reduced torque ripple. An evolutionary algorithm (EA) is adopted to improve the SSPM and optimize its torque performance, significantly reducing torque ripple without sacrificing average torque. The comprehensive assessment provides valuable insights into the relative strengths and limitations of each rotor topology for various application scenarios. Full article

The Aristarchus Plateau (AP) is one of the most volcanically complex regions of the Moon and has long attracted geological interest. In this study, the microwave radiometer (MRM) data acquired by the Chang’e-2 satellite were used to evaluate the thermophysical characteristics of surface deposits across the AP and the adjacent regions. The time–angle method and bilinear interpolation were applied to generate brightness temperature (TB) maps at specific local times. A reference TB was introduced to obtain the normalized TB (nTB) maps, thereby substantially reducing the latitudinal variation in TB. The microwave thermal emission characteristics of the AP and its vicinity were subsequently analyzed in the context of previous geologic studies. The main results are as follows: (1) The lunar pyroclastic deposits (LPDs) have a high heat-storage capacity, which keeps them warmer than adjacent mare deposits throughout the night and into the following morning. (2) The subsurface temperature or geothermal heat flux of the AP appears to be higher than that of the adjacent Oceanus Procellarum. (3) The spatial extent of the LPDs is probably much larger than that recognized in optical and radar observations, extending broadly eastward to encompass regions including Montes Harbinger and northward to encompass regions including Montes Agricola. (4) A revised evolutionary framework for the LPDs is proposed by integrating their spatial extent derived from MRM observations with geologic boundaries interpreted from optical observation. The results demonstrate the potential value of CE-2 MRM data for investigating early lunar explosive volcanism. Full article

Revealing the spatiotemporal patterns and controlling factors of atmospheric CO₂ in the Sichuan Basin (SCB) is a prerequisite for the scientific regulation of regional carbon sources and sinks. This study investigates surface and column-averaged CO₂ concentrations in SCB and surrounding regions during August to December 2024, using in situ measurements, Orbiting Carbon Observatory-3 (OCO-3) column-averaged CO₂ retrievals, and a Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) simulations and footprint analysis. At the national atmospheric background site JinFoShan (JFS), observed CO₂ concentrations rose from ~404 ppm in mid-August to around 440 ppm by late December. Comparisons between observations at JFS and WRF-Chem show that simulations driven by Open-source Data Inventory for Anthropogenic CO₂ (ODIAC) fossil fuel emissions and Vegetation-Global-Atmosphere-Soil (VEGAS) biosphere fluxes yield the highest Pearson correlation coefficient (r = 0.77). The diurnal and seasonal variabilities at JFS are primarily controlled by biospheric fluxes, with fossil fuel contributions weak in August to September and slightly enhanced in October to December, partly due to regional transport from downtown Chongqing revealed by footprint analysis. By contrast, Yongchuan station, closer to urban Chongqing, shows mean CO₂ levels ~10 ppm higher than JFS. For satellite observations, OCO-3 Snapshot Area Map (SAM) measurements over the SCB suffer from substantial missing samples and high spatial noise. We find no spatial correlation exists between SAM retrievals and simulations over Chongqing, and only weak positive correlations appear over Chengdu using ODIAC and Gridded Fossil Emissions Datasets (GridFEDs), whereas results based on the Multi-resolution Emission Inventory for China (MEIC) show no correlation, likely related to biased suburban emission spatial distributions. Overall, the spatial correlations between SAM retrievals and model simulations are weak, ranging from −0.22 to 0.31. To our knowledge, this is the first study to systematically compare in situ observations and OCO-3 SAM retrievals with WRF-Chem simulations in the Sichuan Basin. Full article

Osmotic energy conversion (blue energy), serving as a sustainable marine renewable energy source, converts Gibbs free energy originating from salt concentration differences into electric power by virtue of ion-selective nanofluidic membranes. Conventional commercial ion-exchange polymer membranes suffer from inherent limitations, including low transmembrane flux, insufficient ion permselectivity, severe interfacial concentration polarization, poor salt tolerance, and unsatisfactory long-term structural stability. These drawbacks greatly restrict the energy conversion efficiency and large-scale engineering application of reverse electrodialysis (RED). Conductive polymers (CPs), mainly including polypyrrole (PPy), polyaniline (PANI), polythiophene (PTh), and their derivatives, possess the distinctive merits of tunable surface charge density and polarity, outstanding electronic conductivity, facile nanochannel structural regulation, and reversible redox responsiveness, making them ideal building blocks for advanced nanofluidic membranes for high-efficiency osmotic energy conversion. This review summarizes recent progress in the fabrication of conductive polymer-based nanofluidic membranes, comprehensively compares the osmotic output performance of typical CP material systems, and discusses the core metrics of osmotic energy conversion output performance. By providing an overview of these developments, this review aims to offer insights into the future development of conductive polymer-based nanofluidic membranes for osmotic energy conversion. Full article

Urbanization is a pervasive form of land-use change that alters surface energy, carbon, and water fluxes. Using the Simple Biosphere 2 (SiB2) land surface model, we quantify the effects of urban land transformation on land surface temperature (LST), gross primary productivity (GPP), and surface water discharge across Morocco. We find that urban effects on LST exhibit strong seasonality as urban areas are consistently warmer than surrounding rural land in winter, whereas summer conditions can produce urban heat sink effects, with rural surfaces becoming warmer than urban centers by up to 0.4 °C as a seasonal mean. We quantify the relationship between urbanization intensity and its local impact on LST, showing that it holds strongly throughout most of the year but weakens in summer, when background regional climate and topography play a greater role. Urbanization was found to reduce ecosystem productivity, with the largest urban induced GPP losses occurring in northern urban settings. Across the Climate Modeling Grid (CMG) cells meeting the study’s inclusion criterion of ≥5% impervious surface area (ISA), three counterfactual pre-urbanization scenarios were developed to quantify the range of GPP losses associated with urban land transformation, estimating potential losses of up to 120 Gg C/year when urbanization occurs on the most productive vegetative land covers. We also show that impervious surfaces systematically increase surface runoff, particularly during autumn and winter in northern Mediterranean cities, where elevated rainfall may amplify flash-flood susceptibility. These results indicate that urbanization exerts a measurable and policy-relevant influence on Morocco’s surface energy, water and carbon budgets, underscoring the need to account for it in future development planning. Full article

Automotive thermal-comfort studies commonly focus on interactions between occupants and cabin air, although the seat forms the principal sustained contact interface between an occupant and a vehicle. This study presents a coupled computational fluid dynamics (CFD) framework that simultaneously resolves heat conduction through perforated leather, breathable sponge, heating pads, and foam; porous airflow through the seat; seat heating and ventilation; and convective heat transfer between the occupant and cabin air. Four total seat-heating powers (0, 60, 90, and 120 W) and four ventilation-fan speeds (0, 1500, 3000, and 4500 rpm) were simulated for 900 s. The results show that seat heating primarily alters temperatures in the contact region through conduction, whereas seat ventilation increases local airflow and cooling near the edges of ventilated contact regions. The principal contribution is a reproducible interface between cabin CFD and thermophysiological modeling. The framework generates spatially resolved fields of air temperature, air velocity, skin and contact-surface temperatures, and heat flux that can serve as boundary conditions for physiological models such as the Fiala and Berkeley models and for subsequent experimental validation. Because the present calculations constitute a comparative single-driver study, direct experimental validation, active thermoregulation, subjective thermal sensation, and interactions under full occupancy must be addressed before the framework can provide absolute comfort predictions. Full article

Molecular transport of low-volatility organic vapors through unsaturated porous media is governed by the coupled effects of diffusion, sorption, and pore structure, yet the relative roles of these processes remain insufficiently quantified. In this work, we develop a physics-based model describing vapor migration from a subsurface source to the soil surface by explicitly accounting for moisture-dependent sorption, air-filled porosity, and pore clogging by fine particles. The model predicts that soil moisture affects vapor transport through two competing mechanisms: thin water films progressively suppress gas–solid sorption, thereby increasing the effective diffusion coefficient, whereas further wetting reduces the connectivity of air-filled pores and ultimately blocks gas-phase transport. As a consequence, vapor migration exhibits a non-monotonic dependence on soil moisture, with a distinct optimum for surface vapor flux. The model further predicts that fine particles substantially decrease vapor transport by reducing pore connectivity, while lower temperatures suppress migration through both reduced molecular diffusivity and enhanced sorption. Laboratory experiments using representative low-volatility energetic compounds through sand with controlled moisture content and particle composition confirmed all major qualitative predictions of the model, including enhanced transport at intermediate moisture, suppression under dry, dusty and highly saturated conditions, and strong temperature dependence. Although energetic compounds were used as representative low-volatility substances, the proposed framework is generally applicable to molecular transport of trace organic vapors in unsaturated porous media and provides a quantitative basis for predicting environmental conditions under which subsurface sources can be detected by surface vapor measurements. Full article

During the production of wet-process phosphoric acid, large quantities of acidic wastewater rich in phosphorus, fluoride and other components are inevitably generated. Selective separation and efficient enrichment of phosphorus and fluoride from such wastewater using appropriate technologies are conducive to resource recovery and recycling, thereby contributing to the sustainable development of the wet-process phosphoric acid industry. In this study, four commercial nanofiltration membranes with different molecular weight cutoffs were selected to treat acidic water from a phosphorus-chemical plant in Guizhou Province, China. The results show that metal ion rejection is governed not only by the membrane pore structure but also by the speciation of the ions in the acidic water system, whereas anion rejection is determined jointly by size sieving and ionic speciation. Among the four membranes, NF7 possesses the smoothest surface, the best hydrophilicity, a positive charge under the experimental condition, and a relatively broad pore size distribution. These characteristics enable NF7 to exhibit the highest pure water flux (62 L·m⁻²·h⁻¹) and maintain >90% rejection of Fe³⁺ and Mg²⁺ while allowing >70% permeation of phosphorus and fluoride, demonstrating considerable potential for the purification of phosphorus-fluoride-containing acidic wastewater generated during wet-process phosphoric acid production. Full article

The deep-sea tunnels at the Sanshan Island Gold Mine are subjected to extreme conditions characterized by high stress and complex erosion resulting from high mineralization. Under these conditions, conventional shotcrete is prone to performance degradation and insufficient durability, posing a threat to the long-term safety of the tunnels. At the same time, mine water is difficult to recycle on-site. To address these engineering challenges, this study utilized fly ash (FA), S105-grade ground granulated blast furnace slag (GGBS), polypropylene coarse fiber (PPCF), and hydroxypropyl methylcellulose (HPMC) as modifying components and employed the response surface method (RSM) to optimize the mix design of mine water-blended shotcrete. The study selected compressive strength, direct shear strength, and chloride ion electrical flux at 6 h as response indicators and constructed a quadratic polynomial regression model. Analysis of variance and goodness-of-fit tests indicated that the model possessed good significance and reliability of fit. Based on this model, the optimal mix design was determined: an FA/GGBS blend ratio of 3:7, a cement replacement rate of 20%, a PPCF content of 3.3%, and an HPMC content of 0.18%. Performance testing showed that the optimal mixture achieved a compressive strength of 25.24 MPa, a direct shear strength of 8.08 MPa, and a chloride ion electrical flux of 778 C after 6 h. Compared to the control group, its peak compressive strength decreased by only 9.98%, while its residual strength increased significantly; direct shear strength increased by 18.1%, and electrical flux decreased by 33.8%. This indicates that the material’s mechanical load-bearing capacity, deformation coordination, and corrosion resistance have been enhanced in a synergistic manner. Field industrial trials have verified that this modified concrete possesses excellent ductile yield characteristics, can effectively suppress water seepage in mine tunnels, is capable of withstanding extreme underground operating conditions, and enables the efficient reuse of mine water resources. Full article

Engineering components often require different properties in different regions, and a single material may not provide all of them. Reliable joining is important for refractory metal–steel, dissimilar superalloy, and Ti/Mg combinations. Field-assisted sintering technology/spark plasma sintering (FAST/SPS) combines pressure with rapid heating for direct joining and fabrication of interlayered and graded metallic structures in short cycles. This review evaluates factors affecting bond formation and mechanical integrity at FAST/SPS-processed metallic interfaces. Sufficient real contact is needed for load transfer but does not alone ensure mechanical integrity. Surface oxides can restrict contact, while local deformation may increase contact area and disrupt oxide films. As contact develops, atomic transport and interfacial reactions may alter transition-region composition and phase morphology, affecting fracture paths. Interlayers may improve contact and limit undesirable reactions but can also create new interfaces and reaction regions. Compositional transitions, reaction regions, and local hardness indicate interface development, but assessing their mechanical significance requires mechanical testing and fracture analysis. Room-temperature performance alone does not define service behavior. Thermal cycling, high heat flux, electrical conditions, or corrosive environments may therefore require application-specific evaluation. Differences in materials, equipment, geometry, and test methods limit direct comparison. Processing windows should therefore be tailored to each material pair and interface architecture according to operating temperature, loading, functional requirements, and environmental exposure. Full article

The electrification of ground transport is advancing under a constraint that is as much geopolitical as technical: the rare-earth elements used in high-energy permanent magnets, and especially the heavy-rare-earth additions required for high-coercivity grades, come from a highly concentrated and recently restricted value chain. This review examines how the imperative to reduce or eliminate rare-earth permanent magnets is reshaping traction-machine design across ground-vehicle segments, from city cars and hypercars to racing prototypes, heavy-duty and mining trucks, and agricultural tractors. Adopting a design-oriented perspective, it links each segment’s torque–speed and cost envelope to coordinated choices of topology, magnet strategy, soft-magnetic and conductor materials, and winding architecture. The principal candidate topologies—interior and surface permanent magnet, induction, synchronous reluctance, permanent-magnet-assisted synchronous reluctance, wound-field synchronous, and emerging axial-flux machines—are compared quantitatively and selected topologies are illustrated through previously published design case studies. The picture is nuanced: permanent-magnet machines still dominate the market, yet in representative like-for-like studies the drive-cycle efficiency penalty of magnet-free machines can be small and wound-field machines are emerging as a leading magnet-free alternative within specific operating envelopes. Full article

Recent lattice studies have revealed that the color flux tube between static quark–antiquark pairs exhibits an excess entanglement entropy (flux-tube entanglement entropy, FTE²) that scales linearly with the quark separation $\mathrm{L}$. In this paper, we demonstrate similar behavior in a string-net model based on $\mathrm{S}\mathrm{U}(2{)}_{\mathrm{k}}$ fusion categories, where the nontrivial object $\mathrm{j}=1/2$ (analogous to color charge) cannot exist in isolation due to the fusion rules, naturally exhibiting “confinement”. We compute the entanglement entropy of the flux tube connecting two $\mathrm{j}=1/2$ objects using the microcanonical (equal-weight) prescription $\mathrm{S}\left(\mathrm{R}\right)=\ln (\dim (\mathrm{H}\mathrm{o}\mathrm{m}\left(\mathrm{R}\right)\left)\right)$ and find an entropy density ${\mathsf{\sigma }}_{\mathrm{k}}=\ln {\mathrm{d}}_{1/2}=\ln (2\cos {\displaystyle \frac{\mathsf{\pi }}{\mathrm{k}+2}})$. For $k=3$, the category reduces to the Fibonacci case, yielding an entropy density σ₃ = ln φ ≈ 0.4812 (φ is the golden ratio), which is qualitatively comparable in magnitude to the scale inferred from lattice studies and the entropy surface mechanism. Under a thermalization assumption for the fusion-channel degrees of freedom, minimizing the free energy $\mathrm{F}=(\mathcal{J}-\mathrm{T}{\mathsf{\sigma }}_{\mathrm{k}})\mathrm{L}$ yields a confinement–deconfinement transition at $({\mathrm{T}}_{\mathrm{c}}=\mathcal{J}/{\mathsf{\sigma }}_{\mathrm{k}})$, which is first-order-like (tension sign reversal) rather than a continuous critical transition. The parameter $\mathrm{k}$ offers a tunable knob, making the $\mathrm{S}\mathrm{U}(2{)}_{\mathrm{k}}$ family a computable laboratory for entropic confinement. The predicted entropy-density jump can be directly tested in quantum simulator platforms (e.g., Rydberg arrays or superconducting circuits) that realize Fibonacci anyonic models. Full article

Freshwater scarcity and rising wastewater generation have intensified global reliance on desalination and reuse, with reverse osmosis (RO) providing 65–70% of installed desalination capacity and achieving energy reductions from 15 kWhm⁻³ in the 1970s to 1.8–2.5 kWhm⁻³ today. However, fouling caused by organics, inorganics, microorganisms, and colloids remains the major operational challenge, accounting for ≈25% of RO costs and over USD 15 billion annually. This review synthesises fouling mechanisms and mitigation strategies in renewable energy (RE)-driven RO wastewater-treatment systems, where intermittency exacerbates fouling through start–stop cycles and low-shear conditions. Analysis of recent literature highlights that mixed fouling reduces flux by 10–30%, increases transmembrane pressure, and deteriorates permeate quality. Advances in pretreatment (coagulation, MF/UF), antifouling membranes (hydrophilic coatings, zwitterionic surfaces), and cleaning protocols (osmotic backwashing, nanobubbles) have improved performance, yet complete prevention remains elusive. Persistent gaps include predictive fouling models, standardised performance metrics, and scalable green chemistries for silica and combined fouling control. Future directions emphasise integrated solutions combining advanced materials, AI-driven monitoring, and renewable-aware operational strategies, alongside circular economy approaches for brine valorisation. These innovations are critical for achieving sustainable, low-carbon RO systems for global water security. Full article

Atmospheric blocking is a major feature of mid-latitude circulation and is closely associated with the occurrence of extreme weather events over Europe. Among the different blocking regimes, Omega blocks are characterized by their persistent tripolar structure, which favors the development of prolonged heatwaves. In late June 2026, a major early—summer heatwave affected Western and Central Europe. This study investigates the synoptic, dynamical, and climatic mechanisms associated with this event using ERA5 reanalysis data. The evolution of the 500 hPa geopotential height, 850 hPa temperature, polar jet stream, Rossby wave breaking, and dynamical tropopause (2 PVU) was analyzed together with anomalies in sea surface temperature (SST), meridional temperature gradient, soil moisture, and sensible heat flux. The results show that the heatwave developed under a persistent Omega blocking pattern, which promoted strong subsidence, enhanced solar heating, and sustained warm air advection over Western Europe. Anomalously dry soils and enhanced sensible heat flux were also observed, suggesting a potential amplifying role of land–atmosphere interactions during the event. In addition, a pronounced cold SST anomaly over the subpolar North Atlantic preceded the onset of the blocking and coincided with a weakened meridional temperature gradient and reduced lower-tropospheric baroclinicity along the climatological position of the polar jet stream. Findings align with studies that North Atlantic cooling, including weakened Atlantic Meridional Overturning Circulation (AMOC), may favor summer Omega blocking and European heatwaves. However, the June 2026 SST anomaly’s origin is undetermined from this single analysis and is not attributed to AMOC variability. Full article

Indoor air temperature influences heat exchange between sleeping infants and indoor environments, yet its effects on convective and radiative dry heat transfer in ordinary ventilated rooms remain unclear. Using a previously validated three-dimensional CFD model of a realistic 9-month-old nude infant thermal manikin, this study simulated body-surface heat transfer at 18, 21, 23, 25, and 28 °C. A low-Re k-epsilon turbulence model was coupled with a surface-to-surface radiation model to calculate convective and radiative heat fluxes and heat transfer coefficients. Results showed that chamber airflow displaced the infant thermal plume toward the feet, exposing the head to cooler air and creating warmer microclimates around the lower limbs. At 18 °C, whole-body convective and radiative heat fluxes were 76.65 and 68.16 W/m², respectively; each 1 °C temperature increase reduced them by 5.24 and 3.74 W/m². Convection dominated at ≤21 °C, while radiation became dominant above 23 °C. The head showed the greatest temperature sensitivity, with convective and radiative heat fluxes decreasing by 61.08 and 41.66 W/m² from 18 to 28 °C. Empirical equations based on skin-to-environment temperature differences fitted most heat transfer coefficients well (R² > 0.93), providing boundary condition data for infant thermoregulation modeling and room thermal control. Full article