Search Results (2,362)

Aluminium is increasingly being adopted in large-scale structural applications due to its high strength-to-weight ratio, corrosion resistance, and excellent recyclability, making it attractive for automotive, aerospace, infrastructure, and renewable energy sectors. Despite these advantages, welding remains a major barrier to the wider use of aluminium in load-carrying structures. This challenge is particularly critical for precipitation-hardened 6xxx series aluminium alloys, where welding-induced thermal cycles can lead to significant strength degradation in the heat-affected zone (HAZ). Strength losses of up to approximately 50% may occur as a result of precipitate dissolution and coarsening. In addition, weld quality can be further compromised by defects such as porosity and lack of fusion. Laser-based welding has emerged as a promising alternative to conventional arc welding due to its high energy density and low overall heat input. These characteristics enable narrower HAZ, reduced distortion, and improved mechanical performance of welded joints, while also offering high productivity and potential cost reductions in the fabrication of large aluminium structures. This paper details industrial challenges, weldability limits, and the mechanisms of beam oscillation, which has emerged as a primary solution for stabilising the keyhole, suppressing porosity, and refining microstructure. A case study has also been included in this paper to show the potential of laser oscillation in pore suppressing in hybrid laser-arc welding (HLAW) of 6082 aluminium. Full article

Building-integrated photovoltaics (BIPVs) can expand the available photovoltaic area on buildings, especially in dense urban contexts with limited roof surfaces. For transparent-envelope applications, such as photovoltaic shading devices (PVSDs) and semi-transparent photovoltaic glazing (STPV), PV-yield assessment is particularly challenging because PV elements also function as part of the building envelope. Their energy yield depends on multiple interacting factors: irradiation, orientation, shading, incidence-angle effects, operating temperature, and, for STPV, glazing thermal behavior. In early-stage building design, however, these effects must be assessed while system characteristics are still evolving, and detailed product or module data are often unavailable. To address this gap, this study develops and evaluates an EnergyPlus-based approach for PV-yield assessments for transparent-envelope BIPV applications. The approach replaces fixed PV efficiency with a time-dependent effective efficiency that accounts for incidence-angle reflection and temperature-related efficiency losses. It is evaluated through a cross-tool comparison with established PV-yield assessment tools. For PVSD, the comparison separates unshaded conditions, louver self-shading, and urban-context shading. For STPV, it includes an analysis of the PV cell-temperature estimation and the link between electricity generation and glazing heat balance. Results show that PVSD yield differences are mainly governed by shading representation, while STPV results are more sensitive to cell-temperature assessment than to thermal coupling effects. Overall, the approach provides a consistent basis for comparing PVSD and STPV yield under early-stage input constraints, while including selected AOI- and temperature-related efficiency effects. Full article

Directional longwave radiation from building heating equipment depends on surface temperature, geometry, projected area, viewing direction, and emissivity. Previous visible–thermal fusion and three-dimensional thermography studies mainly produce fused maps or visual models; this study systematizes a workflow for projected-area-weighted directional radiant intensity. Geometric contours from synchronized visible images are transferred to thermal images to reconstruct a three-dimensional thermal model. For a small radiant electric heater, the visible-image-assisted method was compared with an indirect method using the same archived thermal input, target object, calculation convention, and unit-emissivity setting (ε = 1). Across 23 directions, the mean absolute error (MAE), root mean square error (RMSE), mean absolute percentage error (MAPE), and coefficient of determination (R²) were 0.47 W/sr, 0.56 W/sr, 3.55%, and 0.996, indicating close method-to-method agreement rather than absolute accuracy. Application to a building-integrated thermal-storage heater produced 28.7–52.76 W/sr. A reusable three-dimensional thermal model can support multi-directional post-processing from one synchronized imaging campaign and may reduce repeated instrument repositioning; however, no time–cost study was available to quantify labor or operational savings. Independent traceable reference measurements, repeated trials, surface-specific emissivity verification, and registration/geometry uncertainty analysis are still required. Full article

This study investigates the effects of powder type and layer-dependent energy input on the structural and mechanical performance of multi-layer laser cladding applied on FGS600-3A ductile cast iron. Three cladding powders (Ferro 55, Castolin 16604, and Metco 41C) were deposited under constant and variable energy input to examine the effects on macrostructure, porosity, microhardness, residual stresses, and thermal history. The results demonstrate that powder composition plays a decisive role in deposition quality. Ferro 55 exhibited the lowest porosity and the most favorable hardness distribution, whereas Metco 41C had high porosity, low hardness, and severe transverse cracking. Castolin 16604 displayed intermediate performance with deeper high-hardness penetration. Layer-dependent energy strategies improved porosity and hardness behavior for Ferro 55 and Castolin 16604; however, excessively low energy input limited hardness depth. Residual stress measurements revealed low stress levels for Ferro 55, compressive stress for Castolin 16604, and high tensile stress for Metco 41C, correlating strongly with cracking tendency. Overall, Ferro 55 and Castolin 16604 were identified as suitable candidates for multi-layer repair and surface modification of cast iron molds, while Metco 41C demonstrated limited applicability due to its porosity, hardness, and stress characteristics. This study emphasizes the importance of layer-specific parameter optimization to achieve defect-free and mechanically strong laser cladding. Full article

Eutrophication in tropical endorheic lakes often persists despite reductions in external nutrient inputs, indicating an important role of internal nutrient loading. However, integrated evidence linking thermal stratification, sediment characteristics, and sediment-derived nutrient release in tropical endorheic lakes remains limited. This study investigated the mechanisms contributing to eutrophication in Lake Batur, a tropical endorheic volcanic lake in Indonesia, through seasonal water-column observations, sediment porewater profiling, diffusive nutrient flux analysis, and sediment characterization. Seasonal observations showed thermal stratification accompanied by hypoxic to anoxic bottom waters, while sediment-derived nutrient flux was dominated by ammonium and phosphate under reducing conditions. Sediment characterization at the representative sampling site revealed mineral assemblages dominated by biogenic silica, aluminosilicate clays, carbonates, and iron-bearing phases that may influence nutrient mobility under low-oxygen conditions. The results indicate strong coupling between thermal stratification, hypolimnetic oxygen depletion, and sediment–water interactions, suggesting that internal loading contributes to maintaining eutrophic conditions in Lake Batur. The endorheic nature of the lake likely enhances nutrient retention because of limited hydrological flushing and prolonged nutrient residence times. These findings improve understanding of eutrophication processes in tropical endorheic volcanic lakes and highlight the importance of considering sediment-derived internal loading together with external nutrient reduction in lake restoration strategies. Full article

Lacustrine shales are globally important both as archives of paleoenvironmental change and as unconventional hydrocarbon reservoirs. The first Member of the Upper Cretaceous Qingshankou Formation in the Songliao Basin, NE China, represents a prominent interval of high-quality petroleum source rocks. Despite their significance, the factors governing organic matter accumulation and pore evolution in these lacustrine deposits remain inadequately constrained, especially with respect to the interplay between paleoenvironmental conditions and porosity development. This research explores the geochemical, mineralogical, and pore structure features of lacustrine shales and mudstones from this formation. The samples analyzed display TOC contents between 0.62 and 3.13 wt%, with Rock-Eval pyrolysis results (T_max avg. 439 °C) reflecting thermal maturity spanning the early to peak oil window. Mineralogically, the samples are dominated by quartz (avg. 28 wt%) and clay minerals (avg. 51 wt%), with feldspar as a minor component (avg. 14 wt%). Geochemical proxies suggest deposition under arid to semi-arid climatic conditions, characterized by minimal chemical weathering, elevated paleo-salinity (Sr/Ba avg. 0.89; 100 × Mg/Al avg. 14.94), and predominantly suboxic to oxic bottom-water conditions (U/Th avg. 0.38; Ni/Co avg. 1.77). Organic matter enrichment is primarily driven by high paleoproductivity (Cu/Al avg. 3.77 × 10⁻⁴) and stratified water columns, while detrital input (Zr/Al ratio) is unfavorable for organic matter accumulation. Pore structure analysis reveals micropore volumes averaging 0.0053 cm³/g and meso- and macropore volumes averaging 0.0233 cm³/g. The contents of quartz and clay minerals exhibit no substantial correlation with pore volume, likely due to secondary quartz overgrowth and mechanical compaction. Similarly, the weak negative correlation between TOC and pore volume is attributed to the poorly developed pore networks within kerogen. This study provides new insights into the depositional and diagenetic controls on organic matter accumulation and pore development in the lacustrine Qingshankou Formation, with implications for paleoenvironmental reconstruction and unconventional hydrocarbon exploration in analogous lacustrine basins worldwide. Full article

Thermophysical properties of thermal plasmas are essential input data for computational models. The required data are usually taken from the literature without examination of their reliability. Cross-code verifications of properties are rare in the thermal plasma literature, partly due to the complexity of the calculation methods, which require a systematic treatment of large datasets, multiple computations and the adoption of different models. Here, a detailed comparison of two computational codes that use different workflows but very similar underlying methods is presented, using the example of thermophysical properties of argon, krypton, and xenon plasmas in local thermodynamic equilibrium at pressures from 1 to 100 atm. The comparison considers plasma composition, collision integrals, thermodynamic properties and, in particular, transport coefficients. The comparison allowed inconsistencies and errors to be identified and corrected, resulting in improved thermophysical properties of argon, krypton, and xenon. Furthermore, transport coefficients obtained from state-of-the-art intermolecular potentials were compared with those obtained from the simpler phenomenological potential, demonstrating good agreement, including at high pressures. Full article

Coral reef ecosystems of the Egyptian Red Sea face escalating pressure from compounding climate-driven warming and intensifying coastal development, dual stressors whose spatial expression and governance implications remained insufficiently characterized prior to the designation of the Great Fringing Reef Marine Protected Area under Prime Ministerial Decree No. 4419/2025. This study develops an integrated multi-decadal framework combining 32 years of sea surface temperature and surface current velocity records, two decades of satellite-derived chlorophyll-a observations, and four decades of satellite-derived coral reef extent mapping across five monitored coastal sites. Basin-wide SST warming of ≈1.15 °C is spatially heterogeneous, with the northern coastal sector warming nearly 25% above the southern sector rate. Surface circulation diverges structurally at Ras Banas: acceleration in the north is consistent with enhanced advective dilution of anthropogenic inputs, whereas consistent deceleration in the south (mean −0.03 m/s) is associated with an increased ecological footprint of wadi-derived sediment and nutrient discharge. Sharply localized chlorophyll-a anomalies, reaching 0.97 mg/m³ at Hurghada and spatially congruent with documented development chronologies, are consistent with anthropogenic disruption of oligotrophic water quality as an important contributor to reef degradation at northern sites. Field evidence from 2026 repeat surveys, interpreted alongside documented severe regional bleaching affecting southern Egyptian reefs during 2024, suggests that climate-driven thermal stress constitutes a parallel and active pressure, particularly in the southern sector where thermal and anthropogenic stressors appear to have converged during the period of most acute reef contraction. Landsat-derived losses of 24.1–50.2% across all monitored sites since 1985, including a 33.3% contraction at Halaib–Shalateen between 2022 and 2025 alone, reflect the cumulative outcome of these interacting pressures. These findings support the ecological necessity of the 2025 MPA while identifying spatially differentiated, dual-stressor governance priorities essential to translating its policy commitment into measurable conservation outcomes. Full article

Snow depth and persistence strongly influence ground–atmosphere energy exchange, meltwater input, and the thermal regime of rock glacier systems, yet high-resolution snow monitoring remains scarce in the Southern Carpathians. This study uses multi-temporal Unmanned Aerial Vehicle (UAV) Structure-from-Motion (SfM) photogrammetry to map snow-depth variability and microtopographic controls on the Galeșu Rock Glacier, Retezat Mountains. Eight UAV surveys were conducted between 2023 and 2025, including seven snow-covered acquisitions and one snow-free reference survey in August 2025. Snow depth was derived by DEM differencing and analyzed against morphometric indices, mainly profile curvature and relative topographic position. Results reveal strong spatial heterogeneity, with recurrent snow accumulation in furrowed, concave, and depressional sectors and reduced snow depth on local topographic highs. The 2024 surveys showed substantially deeper snow than 2025, with mean snow depths of 1.82 m in February and 1.62 m in March 2024, compared with 0.72 m and 0.83 m in February and March 2025. April 2023 displayed the deepest snowpack, with a mean snow depth of 2.27 m. Class-based analysis showed median contrasts of 2.30 m in 2024 and 1.20 m in 2025 between strong negative and strong positive curvature classes. These findings demonstrate that rock glacier microtopography exerts a first-order control on snow accumulation and persistence, providing a basis for future studies linking snow redistribution to ground thermal regimes, meltwater pathways, and ground-ice preservation in marginal periglacial environments. Full article

Wet cooling towers are widely used for low-energy thermal management and ventilation support; however, high-fidelity simulations are computationally expensive for large design studies. This work develops a physics-based static reduced-order model for a two-dimensional axisymmetric counterflow wet cooling tower derived from computational fluid dynamics (CFD) simulations coupled with a user-defined source-term formulation for heat and mass transfer in the fill region. A design of experiments based on advanced Latin hypercube sampling generated 210 configurations, of which 168 valid simulations were retained. The active inputs included tower diameter, fill height, inlet air mass flow rate, inlet air temperature, inlet humidity ratio, inlet water mass flow rate, and inlet water temperature, while the cooling range and evaporation rate were selected as target outputs. Five surrogate families were compared by cross-validation. Kriging was statistically most accurate, with $R_{CV}^2$ values of 0.9999 and 0.9998 for the cooling range and evaporation rate, respectively. Second-order quadratic polynomial models were selected as the engineering reduced order model (ROM) because they capture non-linear boundary curvatures with accuracy, achieving $R_{CV}^2\ge 0.9989$ and root mean square errors of 0.0426 K and 0.00042 kg/s while preserving an explicit, directly implementable algebraic form. Sensitivity analysis indicated that the inlet water temperature and air mass flow rate are dominant factors within the sampled domain. Full article

LiDAR sensors provide reliable physical distance measurements using laser signals, enabling accurate acquisition of 3D information for various optical systems. However, they are costly, require significant weight and space, and their reliability and accuracy degrade under adverse environmental and weather conditions. In contrast, thermal cameras operating in the infrared spectrum can capture stable visual information even in challenging scenarios such as nighttime, low-light, and rain. However, they cannot directly provide the physical 3D depth information that LiDAR offers. To design efficient optical systems, there is a growing need for techniques that transform thermal image data into LiDAR-like depth information. While deep learning models can theoretically learn direct mappings between thermal and LiDAR modalities, the scarcity of acquiring paired thermal–LiDAR datasets and the difficulty of acquiring them make this task challenging. In this paper, we propose a thermal image-to-LiDAR depth transformation framework. Our method leverages large-scale pretrained visual models for depth estimation to generate initial depth predictions from thermal inputs. Since pretrained RGB-based models face a modality gap when applied to thermal data, we introduce a two-stage depth refinement. Stage 1 corrects global scale inconsistencies, and Stage 2 refines local structural details. Experiments on the MS2 dataset demonstrate that the proposed framework consistently improves the initial DepthPro outputs across day, night, and rainy conditions. Both quantitative metrics and qualitative comparisons show that RGB-pretrained depth predictions can provide useful structural cues for thermal depth estimation when their global scale and local structural errors are explicitly refined. Full article

With contemporary advancements in additive manufacturing (AM), it has become possible to obtain hull structures for spacecraft made of relatively cheap materials. The possibility of substituting super-austenitic stainless steel Avesta SMO 254 X1NiCrMoCuN20-18-7 (EN 10088) for that already used in the Starship SpaceX 304 L-Modified is focused on achieving better thermal stability and durability in extreme conditions. The Directed Energy Deposition Arc (DED-Arc) method for AM has enabled the production of high-strength-to-weight ratios. The aim is to engage low-cost material with treatment optimization to provide greater corrosion resistance and high yield and tensile strength. For the DED-Arc, a filler wire was selected for the welding source, Fronius TPS 400i. A simulation via the RoboDK Robot Development Kit for the FANUC ARC Mate 100ID10L is provided. Additional shot pining/vibration treatment is proposed for the finished structure, which can be a substitute for the cold-worked initial metal. A comparison is made for stainless steel that has already been tested for space travel. Regimes for the manufacturing process are proposed, with representative samples of Avesta SMO 254 obtained and tested using microhardness measurements, microcracking detection, porosity measurements, interface zone assessment, and microstructural analysis. The DED-Arc process can be applied to large-space shell manufacturing. A comparison is made with a focus on the mechanical and corrosion advantages. For Avesta SMO 254, microhardness measurements ranged from 235 to 246 HV1 and increased after treatment. The controlled parameters provided a maximum heat input of 0.7 KJ/mm, no defects, and a fine microstructure. The successful use of stainless steel with AM increases the potential for multiple space missions. The advanced method shows high quality, allows cost savings and provides extended service life. Full article

Conventional ridge tillage has triggered severe soil organic carbon depletion and soil erosion in sloping maize fields of humid northeast China, posing a persistent threat to black soil health and regional grain security. As representative conservation tillage systems integrated with full straw residue retention, no tillage and strip tillage exhibit prominent potential in soil protection, and their soil-improving benefits are inseparable from continuous straw carbon input; however, their regulatory effects on humus fractions and humic acid molecular properties in erosion-prone sloping farmlands remain largely unclarified. This study aimed to screen the optimal integrated tillage–cultivation mode for sloping farmlands in the northeast China black soil region and to reveal how tillage systems coupled with incremental agronomic practices affect maize yield, humus composition, and humic acid molecular characteristics in Albic soil, a representative degraded soil type of the regional black soil system. A 2-year field experiment was conducted in a typical sloping farmland of Jilin Province, with conventional ridge tillage set as the control. Five incremental integrated management practices (from baseline practice to fertilizer reduction, straw decomposition promotion, and 5–10% higher planting density) were arranged under both under no-tillage and strip-tillage systems. We analyzed dissolved organic matter fluorescence properties, carbon content of humus fractions, and humic acid molecular structural features, and performed principal component analysis for comprehensive performance evaluation of all treatments. This study demonstrates that optimized strip tillage, supported by full straw C input as an indispensable prerequisite, combined with straw decomposition promotion and a 10% planting density increase can synchronously boost soil fertility and maize yield, providing a scientific and practical tillage strategy for sustainable black soil conservation of sloping Albic farmlands in humid northeast China. Strip tillage achieved a 6.78% higher average maize yield than NT, and the maximum yield was recorded with ST5 (strip tillage combined with straw decomposition promotion and 10% planting density increase). Both no tillage and strip tillage significantly increased C_DOM content, humification index and autochthonous contribution, optimized humus component distribution with elevated humic acid carbon content, humic acid carbon-to-fulvic acid carbon ratio and humic acid carbon-to-total organic carbon ratio, and enhanced humic acid aromaticity, thermal stability, and hydrophobicity. The principal component analysis results indicated that ST5 ranked first in comprehensive performance, while conventional ridge tillage ranked the lowest among all treatments. Strip tillage integrated with straw decomposition promotion and 10% increased planting density effectively modulated humus fractions, improved humic acid molecular stability, and synchronously increased maize yield. This integrated management regime provides a scientific and practical tillage strategy for sustainable black soil conservation and high-efficiency maize production in sloping Albic farmlands of humid northeast China. Full article

Canopy temperature (T_c) is an important indicator for characterizing crop water status and serves as the core variable for constructing the Crop Water Stress Index (CWSI). Timely and accurate diagnosis of crop water stress is of great significance for precision irrigation and yield improvement. Owing to its non-contact and high-efficiency characteristics, unmanned aerial vehicle (UAV) remote sensing has become an effective approach for high-spatiotemporal-resolution monitoring of crop water conditions. However, variations in observation geometry can introduce thermal directional effects in canopy temperature, thereby reducing the stability and reliability of CWSI estimation. In this study, multi-angular thermal infrared imagery acquired by a UAV platform was utilized to investigate the directional characteristics of winter wheat canopy temperature. A kernel-driven model was employed to separate the directional components of canopy temperature and retrieve isotropic temperature parameters that more closely represent the actual thermal status of the crop canopy. Based on these temperature parameters, three CWSI models were constructed and evaluated for crop water stress diagnosis. The results demonstrated that (1) winter wheat canopy temperature exhibited pronounced directional characteristics, and the observed temperature generally decreased with increasing relative azimuth angle between the viewing direction and solar incident direction; (2) after angular correction, the isotropic canopy temperature simulated by the kernel-driven model showed an improved correlation with soil moisture content at a depth of 30 cm (R² = 0.54); and (3) when angular-corrected canopy temperature was used as the input variable for different CWSI models, the sensitivity of all models to crop water variation was substantially enhanced, resulting in improved discrimination among different irrigation treatments. Among the evaluated approaches, the empirical CWSI model achieved the best performance in diagnosing crop water stress variations (R² = 0.73, RMSE = 1.59%). These findings provide a theoretical basis for UAV-based thermal infrared remote sensing of crop water status and offer technical support for precision irrigation management. Full article

This study presents the design, manufacturing, and prototype-level evaluation of a high-efficiency interior permanent magnet synchronous motor (IPMSM) developed for compact electric vehicle traction applications. The proposed motor employs a 12-slot/10-pole spoke-type rotor topology and was evaluated in terms of electromagnetic performance, mechanical integrity, and thermal behavior. The slot–pole and winding configuration was assessed as part of the design evaluation, and the manufactured prototype was experimentally tested under different operating conditions. The experimental results were compared with numerical simulations using line-to-line back-EMF, efficiency maps, phase current–torque characteristics, and output power variation. At the nominal operating point of 7000 rpm and 3.5 Nm, the prototype delivered 2.5 kW output power with an experimental efficiency of 90.7%. The deviations between experimental and simulation results were 1.17% for phase current, 0.48% for line-to-line back-EMF, 1.18% for input power, and 1.20% for efficiency. Mechanical static structural finite element analysis indicated a rotor safety factor of 3.61 under the maximum centrifugal loading condition, while the resulting structural deformation remained sufficiently low to avoid adverse effects on air-gap alignment. In addition, the rotor incorporated an adhesive-free, mechanically disassemblable magnet-retention structure, which was mechanically evaluated under centrifugal loading and showed no magnet displacement, structural damage, or bolt-preload loss after testing. Thermal analysis and continuous-load experimental testing showed that the winding temperature remained around 80 °C under passive cooling conditions. Overall, the results demonstrate that the manufactured IPMSM prototype provides consistent electromagnetic performance, adequate mechanical reliability, and thermally safe operation for compact electric vehicle applications. Full article