Search Results (2,101)

In coastal hot and humid regions, the steel pin of AC porcelain insulators often suffers from severe electrochemical corrosion due to surface contamination and moisture, leading to insulator string breakage. Contrary to the common belief that AC corrosion is negligible, this study reveals the significant role of the DC component in leakage currents and the synergy of this DC component with localized high current densities in accelerating corrosion, based on field investigations and experiments. Using a simulation model based on the Suwarno equivalent circuit, it is shown that non-linear contamination causes highly non-sinusoidal leakage currents, with total harmonic distortion up to 40% and a DC component of approximately 22%. To mitigate this, a conductive silicone rubber coating is proposed to block moisture and distribute leakage current evenly, keeping surface current density below the critical threshold of 100 A/m². Simulations indicate that a 2 mm thick coating with conductivity around 10⁻⁴ S/m effectively reduces current density to a safe level. Accelerated corrosion tests confirm that this conductive coating significantly suppresses pitting corrosion caused by high current densities, outperforming traditional insulating coatings. This study presents a practical and effective approach for protecting AC insulators in harsh environments, contributing to improved transmission line reliability in high-temperature and high-humidity regions. Full article

This study investigates the surface characteristics and corrosion behavior of a high-C martensitic stainless steel (AISI 440C) at different stages of its manufacturing process. As a class, these steels prioritize high mechanical properties and wear resistance over superior corrosion resistance. Hot working operations, such as rolling, create a surface oxide scale that must be removed via pickling to restore the material’s inherent corrosion resistance. This process also eliminates the underlying Cr-depleted layer, allowing for the re-establishment of a protective passive film. Using potentiodynamic polarization curves and micrographic analysis, the material’s behavior in different conditions, as-rolled, with a post-heat treatment oxide scale, and in a bare, oxide-free state, has been assessed. The results showed that the material lacks stable passive behavior under all conditions. The as-rolled and heat-treated conditions both exhibited active behavior and formed thick, non-adherent corrosion products. The oxide layer formed after heat treatment performed the worst, showing a significant increase in corrosion current density. These findings confirm the material’s susceptibility to corrosion in Cl⁻ ion-rich environments, highlighting the need for limited storage in such conditions and rapid pickling after thermal processing to mitigate surface damage. Full article

The integration of nanoengineered materials into concrete systems has emerged as a promising strategy for enhancing structural performance and sustainability. This study presents a hybrid experimental-analytical investigation into the use of multilayer graphene as a smart admixture in high-performance concrete. The research combines mechanical testing, microstructural characterization, and a multi-objective optimization model to determine the optimal graphene dosage that maximizes strength gains while minimizing carbon emissions. Concrete specimens incorporating multilayer graphene (ranging from 0.01% to 0.10% by weight of cement) were tested over 7 to 90 days for compressive, tensile, and flexural strengths. Simultaneously, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray analyses revealed crystallinity enhancement, pore densification, and favorable elemental redistribution due to graphene inclusion. A normalized composite objective function was formulated to balance three maximization targets—compressive, tensile, and flexural strength—and one minimization goal—carbon emission. The highest objective score (Z = 1.047) was achieved at 0.10% graphene dosage, indicating the optimal balance of strength performance and environmental efficiency. This dual-framework study not only confirms graphene’s reinforcing effects experimentally but also validates the 0.10% dosage through mathematical scoring. The outcomes position of multilayer graphene as a powerful additive for high-strength, low-carbon concrete, especially suited for infrastructure in hot and arid environments. The proposed optimization approach provides a scalable pathway for performance-based graphene dosing in future innovative concrete formulations. Full article

Urban growth in hot, arid regions intensifies the urban heat island effect, making green spaces vital for climate mitigation. This research investigates the impact of public gardens on the surrounding urban thermal environment and on the mitigation of the urban heat island (UHI) in a hot arid region. This study selects an important public garden in Biskra, the “5 July 1962” Garden, as a case study of significance at the urban scale. To achieve research objectives, onsite measurement using a digital measurement device (5-in-1 Environmental Meter “Extech EN300”) and satellite remote sensing data from LANDSAT8 are employed, capturing summer measurements of key parameters and indices: Land Surface Temperature (LST), Air Temperature (AT), Relative Humidity (RH), Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI) and Normalized Difference Moisture Index (NDMI). The analysis and correlation of these indices with the LST values allow us to evaluate the zoning and distance impacts of the garden studied. Land surface temperature rises gradually from the garden outward, peaking in the North-East with the strongest heat island effect and remaining lower in the cooler, vegetation-rich South-West. The results reveal that air temperature is the primary driver of land surface temperature (72% impact), while relative humidity (17.3%), vegetation index (7.8%), moisture index (2.9%), and water index (1.7%) contribute to cooling, with vegetation and moisture reducing surface temperatures through shading, transpiration, and latent heat exchange. Full article

This study experimentally investigates the mechanical and dynamic hygrothermal behavior of compressed earth block (CEB) walls subjected to simulated climatic cycles representative of a tropical humid environment. Four formulations were tested: raw soil (D0), soil with kenaf fibers (DF), soil with fibers and cement (DFC), and soil with fibers, cement, and slag (DFCL). Performance was assessed in an instrumented bi-climatic cell, enabling the determination of thermal and hygroscopic attenuation factors and time lags, complemented by standardized uniaxial compression and three-point bending tests. DFCL achieved a compressive strength of about 10 MPa, nearly twice that of DF (~6 MPa), exceeding the threshold required for buildings up to R + 1. Regarding hygrothermal behavior, DFCL exhibited the highest thermal attenuation factor (2.24) and a hygroscopic attenuation factor of 2.05, with corresponding time lags of ~0.9 h (thermal) and ~1.1 h (hygroscopic). These results highlight superior thermal inertia and moisture regulation, well suited to the constraints of tropical humid climates. Overall, the findings confirm the potential of kenaf fiber-reinforced cement–slag stabilized CEBs as a sustainable construction solution, particularly for load-bearing walls in hot and humid regions. In addition to technical performance, DFCL also offers environmental and economic advantages, as the use of local fibers and slag reduces Portland cement consumption and costs, reinforcing its sustainability potential in tropical contexts. Full article

Underwater wireless communication (UWC) is an emerging technology crucial for automating marine industries, such as offshore aquaculture and energy production, and military applications. It is a key part of the 6G vision of creating a hyperconnected world for extending connectivity to the underwater environment. Of the three main practicable UWC technologies (acoustic, optical, and radiofrequency), acoustic methods are best for far-reaching links, while optical is best for high-bandwidth communication. Recently, utilizing reconfigurable intelligent surfaces (RISs) has become a hot topic in terrestrial applications, underscoring significant benefits for extending coverage, providing connectivity to blind spots, wireless power transmission, and more. However, the potential for further research works in underwater RIS is vast. Here, for the first time, we conduct an extensive survey of state-of-the-art of RIS and metasurfaces with a focus on underwater applications. Within a holistic perspective, this survey systematically evaluates acoustic, optical, and hybrid RIS, showing that environment-aware channel switching and joint communication architectures could deliver holistic gains over single-domain RIS in the distance–bandwidth trade-off, congestion mitigation, security, and energy efficiency. Additional focus is placed on the current challenges from research and realization perspectives. We discuss recent advances and suggest design considerations for coupling hybrid RIS with optical energy and piezoelectric acoustic energy harvesting, which along with distributed relaying, could realize self-sustainable underwater networks that are highly reliable, long-range, and high throughput. The most impactful future directions seem to be in applying RIS for enhancing underwater links in inhomogeneous environments and overcoming time-varying effects, realizing RIS hardware suitable for the underwater conditions, and achieving simultaneous transmission and reflection (STAR-RIS), and, particularly, in optical links—integrating the latest developments in metasurfaces. Full article

School buildings in hot-humid climates encounter considerable difficulties in balancing energy use and thermal comfort due to this environment, necessitating optimized design strategies to reduce energy consumption while enhancing occupant comfort. This study presents sustainable design strategies for educational structures in hot-humid regions, aiming to optimize energy efficiency and thermal comfort for environmental preservation and occupant welfare. The present work introduces a multi-objective optimization framework for window design in school buildings situated in hot-humid climates, targeting a balance between Energy Use Intensity (EUI) and Thermal Comfort Time Ratio (TCTR). Exploring multi-objective optimization through NSGA-II genetic algorithms, the study conducts Sobol sensitivity analysis for parameter assessment and applies Gaussian Process Regression (GPR) for effective model validation, identifying optimal window configurations that reduce energy consumption while enhancing thermal comfort. It finds that the Window-to-Wall Ratio (WWR) and Solar Heat Gain Coefficient (SHGC) are the most significant factors, with WWR and SHGC accounting for 28.1% and 23.7% of the variance in EUI and TCTR, respectively. The results reveal a non-linear trade-off between the objectives, with the Balanced Solution offering a practical compromise: a 6.7% decrease in energy use and a 14.3% enhancement in thermal comfort. The study examined various ranges of window parameters, including WWR (0.1–0.50), SC (0.20–0.80), K (1.0–2.5 W·m⁻²·K⁻¹), SHGC (0.1–0.4), Shading width (0.3–2.0 m), and Shading angle (0°–90°). The recommended compromise, known as the Balanced Solution, suggests optimal values as follows: WWR = 0.40, SC = 0.30, SHGC = 0.40, K = 1.2 W·m⁻²·K⁻¹, Shading width = 1.22 m, and Shading angle = 28°. The GPR model exhibited high predictive precision, with R² values of 0.91 for EUI and 0.95 for TCTR, underscoring the framework’s effectiveness. This research offers actionable insights for designing energy-efficient and comfortable school buildings in hot-humid climates, enriching sustainable architectural design knowledge. Full article

Climatic heat stress in Hong Kong’s construction industry has been exacerbated by global climate change in recent times and the city has been taking proactive measures in protecting its workforce. Heat stress management systems refer to integrated frameworks, including policies, technologies, and practices, designed to monitor, mitigate, and prevent heat-related risks to workers’ health and productivity in hot environments. This scoping review investigates the existing heat stress management systems within Hong Kong’s construction industry, analyzing policies and academic research, and highlighting challenges and proposing solutions. A systematic scoping method was used to review and synthesize findings from 50 peer-reviewed articles (updated to 2025) and nine policy documents. This study highlights the interplay between research innovations like AI-driven models and wearable cooling technologies and policy frameworks. The results indicate substantial progress in Hong Kong’s drive to manage heat strain and accidents among construction workers over the years, with advancements in real-time advisory systems and protective equipment, improving worker safety and productivity. However, limited scalability, costs, socio-cultural compliance issues, gaps in addressing equity concerns among vulnerable workers, policy implementation, and other challenges persist. This review underscores the importance of building resilient systems against the escalating heat stress risks by proposing the integration of research-based technological innovation with policies and socio-organizational considerations. It contributes to providing the first updated scoping review post-2020, identifying implementation gaps (e.g., 40% non-compliance rate) and proposing a concrete action framework for future interventions. Recommendations for future research include cross-regional adaptations, cost-effective solutions for medium-sized construction enterprises, and the continuous re-evaluation and improvement of current interventions. Full article

Amidst the rapid development of renewable energy, wind power, as a major renewable energy source, has raised ecological concerns regarding its impacts on ecosystems and biodiversity. Insects, as direct displays and feedback of the environment, have become a hot topic in ecology and conservation biology research due to the impact of environmental changes on them. So this study investigates the effects of wind power density on insect diversity and their mechanisms in the Ningxia desert steppe wind farms. The results indicated that minimal disturbance marginally increased insect aggregation at low wind power densities (2 turbines/km²). However, higher wind power densities caused pronounced insect population declines toward turbines (6, 11 turbines/km²), and with the increase in wind power density, the number of insects decreased significantly. Increased wind power disturbance led to decreases in soil total nitrogen (TN), total carbon (TC), nitrate nitrogen (NO₃⁻-N), and soil moisture content (SM) and a significant decrease in total phosphorus (TP). While direct impacts on vegetation were relatively minor and irregular, vegetation height exhibited strong positive correlations with soil nutrient depletion, suggesting that wind-induced soil degradation indirectly constrains plant growth. Consequently, the effect of wind power on insects is mediated through coupled vegetation–soil interactions. These findings underscore the necessity of integrating ecological thresholds into wind farm management protocols. Full article

The Lower Submember of the Second Member of the Lianggaoshan Formation (LGS2-LS) in the Fuling area, southeastern Sichuan Basin, represents the deepest lacustrine depositional stage of the formation and constitutes an important target for shale oil and gas exploration. Based on core observations, thin-section petrography, X-ray diffraction, geochemical analyses, and sedimentary facies interpretation from representative wells, this study characterizes the lithofacies types, sedimentary environments, and depositional evolution of the LGS2-LS. Results show that the LGS2-LS is dominated by clay–quartz assemblages, with average clay mineral and quartz contents of 44.6% and 38.8%, respectively, and can be subdivided into shallow and semi-deep lacustrine subfacies comprising eight microfacies. Geochemical proxies indicate alternating warm-humid and hot-arid paleoclimatic phases, predominantly freshwater conditions, variable redox states, and fluctuations in paleoproductivity. Sedimentary evolution reveals multiple transgressive–regressive cycles, with Sub-layer 6 recording the maximum water depth and deposition of thick organic-rich shales under strongly reducing conditions. The proposed sedimentary model outlines a terrigenous clastic lacustrine system controlled by lake-level fluctuations, transitioning from littoral to shallow-lake to semi-deep-lake environments. The distribution of high-quality organic-rich shales interbedded with sandstones highlights the LGS2-LS as a favorable interval for shale oil and gas accumulation, providing a geological basis for further hydrocarbon exploration in the southeastern Sichuan Basin. Full article

Patio-style dwellings are a highly representative category of traditional dwellings in the Yangtze River Delta region of China. As a crucial climate-adjusting space for traditional dwellings in the hot summer and cold winter zone, patios have long been the focus of practice and research in traditional dwelling renovation. Previous studies have mostly focused on how the shape and scale of patios affect their performance in terms of ventilation, lighting, and thermal environment; however, there is a lack of research on how patio renovation measures influence the thermal comfort of spaces surrounding patios. Based on the two goals of improving the thermal comfort of the general hall space and reducing the overall building energy consumption, this paper takes the patio renovation of Huaigengtang Dwelling as a case study. We use the Design Builder (v7.0.2.006) simulation software to analyze the impact of 10 selected patio measures on thermal comfort and energy consumption and adopt the entropy weight method to conduct a comprehensive evaluation of the indicators for thermal comfort improvement and energy consumption reduction. The quantitative simulation is divided into two scenarios: one where the patio maintains natural ventilation, and the other where the patio is renovated into an enclosed space with split-type air conditioners used for cooling and heating. We select a single patio renovation measure and a combined patio renovation measure based on the values of the comprehensive scores. Regarding the application of the selected optimal measures, and in combination with the dual needs of functional improvement and performance enhancement in traditional dwelling renovation practice, this paper analyzes the corresponding relationships between three types of functional improvement—inheritance-type renovation, optimization-type renovation and replacement-type renovation—and the two performance evaluation indicators, namely thermal comfort improvement and energy consumption reduction, so as to propose the optimal recommendation schemes for different renovation scenarios. Full article

This study was conducted to evaluate the high-temperature protection performance of new hard coating systems. Woka 7202 (Cr₃C₂-NiCr) and Diamalloy 2002 (WC-NiCrFeBSiC) powders were coated onto 316L stainless steel substrates using the atmospheric plasma spraying (APS) method and subjected to isothermal oxidation (5–100 h) and hot corrosion (55% V₂O₅ + 45% Na₂SO₄, 1–5 h) tests. Although the coatings exhibited a laminar microstructure and some pores, cracks, and oxide-containing regions, they did not show any flaking or structural integrity deformations during the tests. Microstructural changes, oxide layer morphology, and the phases formed were examined in detail. The findings demonstrate that these coating systems not only provide chemical and structural stability against existing high-temperature environments, but also meet the requirements of next-generation thermal protection needs. In this regard, the study provides directly applicable information for the coating design and performance optimization for turbine blades, energy production equipment, and similar industrial components exposed to high-temperature oxidation and hot corrosion. Full article

Surface defects in hot-rolled steel strip alter the material’s properties and degrade its overall quality. Especially in real production environments, due to time sensitivity, lightweight Convolutional Neural Network models are suitable for inspecting these defects. However, in real-time applications, the acquired images are subjected to various degradations, including noise, motion blur, and non-uniform illumination. The performance of lightweight CNN models on degraded images is crucial, as improved performance on such images reduces the reliance on preprocessing techniques for image enhancement. Thus, this study focuses on analyzing pre-trained lightweight CNN models for surface defect classification in hot-rolled steel strips under degradation conditions. Six state-of-the-art lightweight CNN architectures—MobileNet-V1, MobileNet-V2, MobileNet-V3, NasNetMobile, ShuffleNet V2 and EfficientNet-B0—are evaluated. Performance is assessed using standard classification metrics. The results indicate that MobileNet-V1 is the most effective model among those used in this study. Additionally, a new performance metric is proposed in this study. Using this metric, the misclassification distribution is evaluated for concentration versus homogeneity, thereby facilitating the identification of areas for model improvement. The proposed metric demonstrates that the MobileNet-V1 exhibits good performance under both low and high degradation conditions in terms of misclassification robustness. Full article

The climate and environment of metropolitan areas have been negatively impacted by swift urbanization and industrialization. Surface Urban Heat Islands (SUHIs) are among the most critical environmental phenomena. This research focused on the spatiotemporal analysis of land use/land cover (LULC) changes in relation to surface urban heat islands and their interconnections from 1992 to 2022. Land Surface Temperature (LST), LULC, and LULC indices, such as the Normalized Difference Moisture Index (NDMI), Normalized Difference Vegetation Index (NDVI), and Normalized Difference Built-up Index (NDBI), were generated using Landsat data. Urban hot spots (UHSs) were identified, and the Urban Thermal Field Variance Index (UTFVI) was then used to evaluate the spatiotemporal variation in thermal comfort. The results indicated LST values between a low of 14.24 and a maximum of 46.30. Urban areas and exposed surfaces, such as open or bare soil, exhibit the highest surface radiant temperatures. Conversely, regions characterized by vegetation and water bodies have the lowest. Additionally, this study explored the correlation between LULC, LULC indices, LST, and SUHIs. LST and NDBI show a positive relationship because of urbanization and industrialization (R² = 0.57 for the year 1992, R² = 0.38 for the year 2010, and R² = 0.35 for the year 2022), while LST shows an inverse relationship with NDVI and NDMI. Urban development should account for thermal sensitivity in densely populated regions. This study introduced an innovative spatiotemporal framework for monitoring long-term changes in urban surface environments. Furthermore, this research can assist planners in creating urban green spaces in cities of developing nations to minimize the adverse impacts of urban heat islands and improve thermal comfort. Full article

Gulf cities have embarked on ambitious public transport infrastructure initiatives in recent decades to foster more livable and sustainable cities. This investigation explores the interpretations and implementation of Transit-Oriented Development (TOD) principles in two prototypical urban districts: Doha’s West Bay, Qatar, and Riyadh’s King Abdullah Financial District (KAFD), Saudi Arabia. By following a comparative case study approach, the study explores how retrofitted (West Bay) and purpose-built (KAFD) TOD configurations fare regarding land use mix, density, connectivity, transit access, and environmental responsiveness. The comparative methodology was selected to specifically capture the spatial, climatic, and socio-economic complexities of TOD implementation in hyper-arid urban environments. Based on qualitative evidence from stakeholder interviews, spatial assessments, and geospatial indicators—such as metro access buffers, building shape compactness, and TOD proximity classification—the investigation reflects both common challenges and localized adaptations in hot-desert Urbanism. It emerges that, while benefiting from integrated planning and multimodal connectivity, KAFD’s pedestrian realm is delimited by climatic constraints and inactive active transport networks. West Bay, on the other hand, features fragmented public spaces and low TOD cohesion because of automotive planning heritages. However, it holds potential for retrofit through infill development and tactical Urbanism. The results provide transferable insights that can inform TOD strategies in other Gulf and international contexts facing similar sustainability and mobility challenges. By finalizing strategic recommendations for urban livability improvement through context-adaptive TOD approaches in Gulf cities, the study contributes to the wider discussion of sustainable Urbanism in rapidly changing environments and supplies a reproducible assessment frame for future TOD planning. This study contributes new knowledge by advancing a context-adaptive TOD framework tailored to the unique conditions of hyper-arid Gulf cities. Full article