Search Results (379)

This study conducted experiments and simulations to examine the DC corona-generated space charge characteristics and understand the performance of high-voltage direct current (HVDC) transmission lines. In experimental studies, various gradient temperatures are tested on a standard model of the potential HVDC transmission line in Southern Africa using an indoor corona cage. Initial tests on the single-line model of aluminium TERN conductors measured the DC corona inception voltages (CIVs) as the ambient temperature increased from 25 °C to 42 °C. A daylight ultraviolet corona camera (CoroCam8) has been used for measurements and visualisation; the measurements record temperatures for positive and negative direct current (DC) voltages. Experimental investigations are supplemented by simulations utilising the finite element method (FEM)-based software COMSOL Multiphysics. Following the creation of 3D models of the corona cage and potential conductor arrangement, the electric field distribution on the surfaces of the conductors was examined. The CIV observations and modelling findings determine the setups’ corona inception electric field strengths. The study effectively integrated experimental data from a corona cage with FEM models to assess DC corona properties across different air temperatures thoroughly. The inception voltage levels of corona are significantly influenced by ambient temperature and the space charge generated by corona. The outcomes of the discussion will inform the design of the proposed HVDC transmission line in Southern Africa. Full article

While deep learning-based image matching methods excel at extracting high-level semantic features from remote sensing data, their performance degrades significantly under cross-daylight conditions and wide-baseline geometric distortions, particularly in multi-source street-view scenarios. This paper presents a novel illumination-invariant framework that synergistically integrates geometric topology and semantic consistency to achieve robust multi-view matching for cross-daylight urban perception. We first design a self-supervised learning paradigm to extract illumination-agnostic features by jointly optimizing local descriptors and global geometric structures across multi-view images. To address extreme perspective variations, a homography-aware transformation module is introduced to stabilize feature representation under large viewpoint changes. Leveraging a graph neural network with hierarchical attention mechanisms, our method dynamically aggregates contextual information from both local keypoints and semantic topology graphs, enabling precise matching in occluded regions and repetitive-textured urban scenes. A dual-branch learning strategy further refines similarity metrics through supervised patch alignment and unsupervised spatial consistency constraints derived from Delaunay triangulation. Finally, a topology-guided multi-plane expansion mechanism propagates initial matches by exploiting the inherent structural regularity of street scenes, effectively suppressing mismatches while expanding coverage. Extensive experiments demonstrate that our framework outperforms state-of-the-art methods, achieving a 6.4% improvement in matching accuracy and a 30.5% reduction in mismatches under cross-daylight conditions. These advancements establish a new benchmark for reliable multi-source image retrieval and localization in dynamic urban environments, with direct applications in autonomous driving systems and large-scale 3D city reconstruction. Full article

The Peruvian grunt, Anisotremus scapularis, is a commercially valuable coastal fish in the southeastern Pacific that is facing overexploitation. To support its aquaculture development, this study evaluated the spontaneous reproductive dynamics of a captive broodstock held under natural photoperiod and temperature conditions in a flow-through system. Eleven wild adult specimens (3 females and 8 males) with an average size of 34.9 ± 5.4 cm and a weight of 986 ± 470 g were housed in a 9 m³ tank and monitored over five consecutive spawning seasons (2016–2021). Fish were fed a semi-moist, animal-protein-based diet (37% protein and 6.6% lipid) at 2% body weight/day. A total of 214 spontaneous spawning events produced over 83 million eggs. The highest reproductive output occurred in the first season (2016–2017) with 94 spawnings and 23.3 million eggs. Fertilization, hatching, and larval survival rates averaged 94.7%, 89.7%, and 75%, respectively, but declined in later years. Spawning showed marked seasonality from October to May, with a major reproductive pause in late January. The temperature (16–20 °C) and photoperiod (>12 h daylight) appeared to influence reproductive timing, alongside diet and broodstock handling. The findings reported herein are observational in nature and provide valuable baseline data for future experimental designs aimed at optimizing broodstock management in A. scapularis aquaculture. Full article

Centralized daylight control has been extensively studied for its ability to optimize useful daylight while mitigating glare in targeted areas. However, this approach lacks a comprehensive visual comfort framework, as it does not simultaneously address spatial glare distribution, uniform high useful daylight levels across all sensor points, and overheating prevention through regulated annual solar exposure. Nevertheless, decentralized control facilitates autonomous operation of the individual façade components, addressing all the objectives. This study integrates a biomimetic functional approach with building performance simulations by computational design to evaluate different kinetic façade configurations. Through the implementation of parametric modeling and daylight analysis, we have identified an optimal angular configuration (60° for the focal region, 50° for the non-focal region) that significantly increases building performance. The optimized design demonstrates substantial improvements, reducing excessive sunlight exposure by 45–55% and glare incidence by 65–72% compared to other dynamic solutions. The recommended steeper angles achieve superior performance, maintaining high useful daylight illuminance (UDI > 91.5%) while dramatically improving visual comfort. Sensitivity analysis indicates that even minor angular adjustments (5–10°) can induce a 10–15% variation in glare performance, emphasizing the necessity of precise control mechanisms in both focal and non-focal regions of the façade. These findings establish a framework for creating responsive building façades that balance daylight provision with occupant comfort in real-time operation. Full article

Building information modeling (BIM) has revolutionized integrated planning by optimizing costs, schedule, and material use. However, building energy modeling (BEM) remains underutilized in early design stages due to interoperability challenges between BIM and BEM tools. This study addresses these challenges by exploring standardized exchange requirements and introducing a novel toolchain that bridges BIM and BEM workflows. In the BIM2IndiLight project, over 400 standardized properties for daylighting, artificial lighting, and façade systems were validated, revealing the advantages and limitations of parameter standardization. Building on these insights, the BIM2BEM-Flow project developed a three-step toolchain that efficiently manages project- and company-specific properties, defines mapping rules, and integrates parameters via a BIM plugin for validated IFC export. The results demonstrate that combining standardized properties with a flexible, workflow-driven toolchain significantly enhances data exchange and interoperability between BIM and BEM. This integrated approach supports early-stage energy performance optimization and offers a promising pathway toward more efficient design processes in the AECO industry. Full article

The rise in temperature worldwide, especially in hot regions with extreme weather conditions, has made climate change one of the critical issues that degrades the solar photovoltaic (PV) system performance. In this paper, a new design of solar cells based on plasmonic thin-film Silver (Ag) technology is introduced. The new design is characterized by enhancing thermal effects, optical power absorption, and output power significantly, thus compensating for the deterioration in the solar cells efficiency when the ambient temperature rises to high levels. The temperature distribution on a PV solar module is determined using a three-dimensional computational fluid dynamics (CFD) model that includes the front glass, crystalline cells, and back sheet. Experimental and analytical results are presented to validate the CFD model. The parameters of temperature distribution, absorbed optical power, and output electrical power are considered to evaluate the device performance during daylight hours in summer. The effects of solar radiation falling on the solar cell, actual temperature of the environment, and wind speed are investigated. The results show that the proposed cells’ temperature is reduced by 1.2 °C thanks to the plasmonic Ag thin-film technology, which leads to enhance 0.48% real value as compared to that in the regular solar cells. Consequently, the absorbed optical power and output electrical power of the new solar cells are improved by 2.344 W and 0.38 W, respectively. Full article

This study investigates the effectiveness of sloped horizontal shading fins in enhancing visual comfort, electricity generation, and acoustic attenuation in a south-facing office room in Wrocław, Poland (51° latitude). A simulation-based approach combined Radiance daylight simulations, PV energy modeling, and graphical acoustic analysis. Four fin configurations were tested to identify the optimal design. The results indicate that Variant 3, featuring two 1 m wide fins inclined at 45°, achieved the best overall performance, increasing UDI_{300–3000/168} from 53.1% to 95.8%, reducing DGP from 50% to 27%, and enabling an estimated annual electricity production of 4.67 MWh. Additionally, applying sound-absorbing material on the shaded side of the fins significantly reduced reflective acoustic wave bounces, significantly reducing façade-exposed noise. This multifunctional solution demonstrates a practical and scalable strategy for improving office environmental quality in temperate climates, contributing to energy efficiency, acoustic comfort, and visual well being. Full article

Urbanisation has significantly transformed human settlements, presenting sustainability challenges, particularly in hot-dry and humid climates. The urban heat island effect and increased energy consumption exacerbate reliance on mechanical cooling and fossil fuels. As climate change escalates, developing sustainable architectural solutions that improve thermal performance and energy efficiency becomes crucial. This study examines the effects of various multilevel courtyard designs on building performance in Abuja, Nigeria, highlighting gaps in applying traditional principles to these models. A mixed-method approach, combining quantitative and qualitative techniques, assesses user perceptions, thermal performance, energy efficiency, and daylighting in multilevel courtyards. Findings indicate that optimised multilevel courtyard configurations yield a 2.15 °C reduction in temperature, enhancing indoor thermal comfort and improving natural ventilation. Users favour multilevel courtyard housing; however, challenges include inadequate daylighting on lower levels and the need for shading solutions. Compressed earth blocks exhibit better thermal performance, reducing peak temperatures by 1.19 °C compared to hollow concrete blocks. Guidelines for architects and urban planners are provided, as well as recommendations for future research on policy incentives to promote multilevel courtyard models. Full article

Effective natural lighting in university library reading areas significantly influences users’ visual comfort, task performance, and energy efficiency. However, existing library lighting designs often exhibit problems such as uneven illumination, excessive glare, and underutilization of natural daylight. To address these challenges, this study proposes a multi-objective optimization framework for library lighting design based on the NSGA-II algorithm. The framework targets the following three key objectives: improving illuminance uniformity, enhancing visual comfort, and reducing lighting energy consumption. The optimization process incorporates four critical visual comfort parameters—desktop illuminance, correlated color temperature, background reflectance, and screen luminance—whose weights were determined using the analytic hierarchy process (AHP) with input from domain experts. A parametric building information model (BIM) was developed in Revit, and lighting simulations were conducted in DIALux Evo to evaluate different design alternatives. Experimental validation was carried out in an actual library setting, with illuminance data collected from five representative measurement points. The results showed that after optimization, lighting uniformity improved from less than 0.1 to 0.6–0.75, glare values (UGR) remained below 22, and daylight area coverage increased by 25%. Moreover, lighting energy consumption was reduced by approximately 20%. Statistical analysis confirmed the significance of the improvements (p < 0.001). This study provides a systematic and reproducible method for optimizing natural lighting in educational spaces and offers practical guidance for energy-efficient and user-centered library design. Full article

To tackle climate change, aircraft designers envision new aircraft concepts which promise to reduce greenhouse gas emissions and enable greener flights. One option is hybrid-electric propulsion architectures. The University of Stuttgart has built and operates such an aircraft, called the e-Genius. This paper aims to demonstrate how far a digital twin is able to replicate a real-world flight using a simplified mission definition and to estimate the range limit for a high-performance hybrid-electric aircraft, lifting the operational constraints faced in the real-world environment. First a digital twin is built and compared to actual flight data to calibrate the model. Next, a comparison with a full flight is performed, using a long-range flight of 2000 km for this purpose. Due to the duration of this flight, weather conditions like wind need to be considered. Validation is performed by comparison to two additional missions, one 500 km mission flown at faster speed and a 1000 km mission flown at a similar speed. To estimate the maximum range based on this calibrated model, operational constraints like daylight and maximum flight time are lifted to see the further potential of the aircraft. This allows the aircraft to fly more slowly, at best cruise speed, and thus estimate the maximum range of the aircraft. Results show good agreement with flight tests for fuel burnt, highlighting however a need to measure additional parameters in future flights. Overall, the model allows us to plan future flights and assess the feasibility of new projects. Full article

Given their dominant role in energy expenditure within China’s Hot Summer and Warm Winter (HSWW) zone, high-fidelity performance prediction and multi-objective optimization framework during the early design phase are critical for achieving sustainable energy efficiency. This study presents an innovative approach integrating machine learning (ML) algorithms and multi-objective genetic optimization to predict and optimize the performance of high-rise office buildings in China’s HSWW zone. By integrating Rhino/Grasshopper parametric modeling, Ladybug Tools performance simulation, and Python programming, this study developed a parametric high-rise office building model and validated five advanced and mature machine learning algorithms for predicting energy use intensity (EUI) and useful daylight illuminance (UDI) based on architectural form parameters under HSWW climatic conditions. The results demonstrate that the CatBoost algorithm outperforms other models with an R² of 0.94 and CVRMSE of 1.57%. The Pareto optimal solutions identify substantial shading dimensions, southeast orientations, high aspect ratios, appropriate spatial depths, and reduced window areas as critical determinants for optimizing EUI and UDI in high-rise office buildings of the HSWW zone. This research fills a gap in the existing literature by systematically investigating the application of ML algorithms to predict the complex relationships between architectural form parameters and performance metrics in high-rise building design. The proposed data-driven optimization framework provides architects and engineers with a scientific decision-making tool for early-stage design, offering methodological guidance for sustainable building design in similar climatic regions. Full article

Architectural design influences both environmental outcomes and occupant behaviors. Green buildings convey environmental responsibility through formal (e.g., signage, tours) and informal means, including natural materials, daylighting, and energy-efficient features. These choices contribute to overall building “atmospherics” that can foster occupant awareness of sustainability. To explore how atmospherics contribute to occupant perception of building sustainability, we surveyed (n = 250) and interviewed (n = 16) occupants of two LEED-certified university buildings—the Green Building and the Green and Biophilic Building—focusing on their awareness of sustainable features and sources of this awareness. The results showed that occupants of the Green and Biophilic Building were significantly more likely to recognize its sustainable features. The diversity and frequency of features identified varied significantly between buildings, with the broader range in the Green and Biophilic Building. Content analysis revealed occupant misconceptions about the sustainability of features like automatic toilets, aesthetic elements, and biophilic patterns, with some assumptions based solely on appearance. These findings highlight how occupants develop green building awareness without formal instruction, underscoring the value of visible design elements in fostering engagement. This study offers practical recommendations for architects and designers to enhance green messaging through non-verbal cues and interpretative educational features. Full article

This study evaluates the impact of light-emitting diode (LED) illuminated signs, known as active road signs, on road safety at urban intersections. Transportation safety specialists emphasize the importance of visibility and placement of signage. LED signs are increasingly deployed at accident-prone locations to improve safety and regulate traffic. This study focuses on stop-controlled intersections (SCIs) in Montréal, Québec, to propose a new backlit sign for evaluation. An unbiased experiment utilizing multinomial logistic regression (MNL) was designed to compare drivers’ reactions to different signage. Microscopic models based on observed turning movement counters (TMCs) were calibrated for conflict estimation using a genetic algorithm (GA). Generalized linear models (GLMs) estimated accident and conflict frequencies under different treatment scenarios. The results showed significant conflict reductions at intersections with LED-backlit signs (BLSs), including 65.5% at night and 46.8% in daylight. Pedestrian crossing conflicts decreased by 55.6% and 27.8%. This study introduces an evaluation framework that integrates driver compliance behavior into simulation and crash modeling to assess a newly designed BLS treatment. It provides a framework for assessing safety treatments in contexts where crash data are limited. Findings offer insights for improving SCIs and enhancing transportation safety using LED stop signs. Full article

Background/objectives: British swimmers are at a heightened risk of vitamin D deficiency (serum 25-hydroxyvitamin D (25(OH)D): <50 nmol∙L⁻¹) as their large indoor training volumes often restrict sunlight exposure, especially during the winter when daylight hours are reduced in the United Kingdom. Previous research has recommended supplementation with 4000 IU∙day⁻¹ vitamin D₃ from October to March to offset vitamin D losses. However, no current study has analysed this approach over multiple seasons to assess if this is an appropriate strategy. Methods: Using a quasi-experimental design, twenty-nine world-class British swimmers (aged 16–30 years) provided a 10 mL venous blood sample (fasted) as part of their routine haematological screening in the September of three consecutive years (2018, 2019, and 2020). Serum 25(OH)D was determined by radioimmunoassay, and this result determined the length of the standardised vitamin D3 protocol (<30 nmol∙L⁻¹: 4000 IU∙day⁻¹ from September to March; 30–79 nmol∙L⁻¹: 4000 IU∙day⁻¹ from October to March; >75 nmol∙L⁻¹: no supplementation). Results: Mean serum 25(OH)D concentrations increased each year (2018: 76.4 ± 28.4 nmol∙L⁻¹, 2019: 91.5 ± 24.8 nmol∙L⁻¹, 2020: 115.0 ± 36.6 nmol∙L⁻¹, p < 0.001), which coincided with the eradication of vitamin D deficiency after one season (prevalence, 2018: 10%, 2019: 0%, 2020: 0%). In September 2020, 35% of swimmers had a serum 25(OH)D > 125 nmol∙L⁻¹, although it is currently debated whether this is a concern or a benefit for athletic populations. Conclusions: Supplementing with 4000 IU∙day⁻¹ of vitamin D₃ throughout the winter can increase the vitamin D status of swimmers. However, more frequent testing may be required to ensure that serum 25(OH)D remains within the sufficient range across the season (75–125 nmol∙L⁻¹). Full article

As the global focus on sustainability intensifies, architects and engineers are increasingly seeking innovative passive strategies to improve building energy efficiency. Among these strategies, the strategic integration of louvers has garnered significant attention due to their potential to optimize building envelope performance and reduce energy consumption. Louvers effectively manage solar heat gain, mitigating the impact of extreme temperatures on indoor spaces. Consequently, louvers reduce the reliance on active HVAC systems, leading to notable energy savings and a decreased carbon footprint. This paper presents a comprehensive review of the role of louvers in enhancing building energy efficiency, highlighting their designs, efficiency, and improvement suggestions. Moreover, this review article addresses potential challenges related to louver design, such as balancing the trade-off between solar heat gain and daylighting and how to optimize louver configurations for specific building types. Approaches to overcome these challenges, including advanced modeling techniques and parametric design, are also explored to assist architects and designers in achieving the most energy-efficient outcomes. Full article