Solar Exposure Research Articles

Novel applications of various neural network models for prediction of photovoltaic system power under outdoor condition of mountainous region

The geography and landscape of mountainous locations are frequently varied, which causes uneven solar radiation exposure in different places which leads to photovoltaic (PV) power generation variation drastically. Therefore accurate PV power prediction is essential for industries in optimize energy production, Energy Planning and Grid Integration, Energy Storage Integration in such diverse conditions. This study aims to predict the power produced by a 2.680 kWp PV under outdoor condition in mountainous region at different time intervals of 10 seconds, 1 minute, 30 minutes, 1 hour and 1 day using different data analytics models. The results show that the radial basis neural network was the most effective model for the intervals of 10 seconds, 1 minute, 30 minutes, and 1 day. Its RMSE was 19.11 W for the 10-second interval, 22.83 W for the 1-minute interval, 25.94 W for the 30-minute interval, and 9.08 W for the 1-day interval. With an RMSE of 23.22 W, the Kernel Ridge Regressor had the best performance for the 1-hour period. This suggests that the model with only two parameters such as temperature and irradiance predict PV power more accurately. The findings can be applied to improve PV system design and performance by precisely forecasting the systems' power output in different weather scenarios.

UV index-based model for predicting synthesis of (pre-)vitamin D3 in the mediterranean basin

The importance of solar radiation for the body’s ability to synthesize Vitamin D3 is well documented, yet the precise amount of sun exposure required to avoid Vitamin D insufficiency is less clear. To address this knowledge gap, this study sought to utilize the sun in a suitable period at the optimum dose by utilizing numerical simulations to determine the amount of Vitamin D3 synthesis in the skin according to season, time of day, and geographical location in Turkey. The study was carried out in three stages; in the first stage, daily, monthly, and annual values were determined in cases where the solar zenith angle has the active UV-B wavelength. The second stage determined the level of Vitamin D that can be synthesized in all skin types at 25% solar radiation exposure. In the third stage, the sun exposure time required for 1000 International Units (IU) for all skin types was calculated. According to the analysis, the yearly period of active synthesis of D3 on Earth lasts from the beginning of March to the third week of October. During the day, it is between 10:00 and 16:00. For 1000 IU/day, the average annual estimated times (minutes) are 5.05 for Type I, 6.3 for Type II, 7.6 for Type III, 11.35 for Type IV, 15.15 for Type V, and 25.25 for Type VI. The results of this paper will impact awareness for academic-medical users.

Artificial Space Weathering to Mimic Solar Wind Enhances the Toxicity of Lunar Dust Simulants in Human Lung Cells.

During NASA's Apollo missions, inhalation of dust particles from lunar regolith was identified as a potential occupational hazard for astronauts. These fine particles adhered tightly to spacesuits and were unavoidably brought into the living areas of the spacecraft. Apollo astronauts reported that exposure to the dust caused intense respiratory and ocular irritation. This problem is a potential challenge for the Artemis Program, which aims to return humans to the Moon for extended stays in this decade. Since lunar dust is "weathered" by space radiation, solar wind, and the incessant bombardment of micrometeorites, we investigated whether treatment of lunar regolith simulants to mimic space weathering enhanced their toxicity. Two such simulants were employed in this research, Lunar Mare Simulant-1 (LMS-1), and Lunar Highlands Simulant-1 (LHS-1), which were added to cultures of human lung epithelial cells (A549) to simulate lung exposure to the dusts. In addition to pulverization, previously shown to increase dust toxicity sharply, the simulants were exposed to hydrogen gas at high temperature as a proxy for solar wind exposure. This treatment further increased the toxicity of both simulants, as measured by the disruption of mitochondrial function, and damage to DNA both in mitochondria and in the nucleus. By testing the effects of supplementing the cells with an antioxidant (N-acetylcysteine), we showed that a substantial component of this toxicity arises from free radicals. It remains to be determined to what extent the radicals arise from the dust itself, as opposed to their active generation by inflammatory processes in the treated cells.

Facile Fabrication of ZnO Nanorods with Extremely Strong Photocatalytic Performance and Antibacterial Activity

Development of nanomaterials with strong antibacterial action and highly enhanced photocatalytic activity for water purification is of immense interest. ZnO nanorods, with extremely enhanced solar-driven photocatalytic performance and good antibacterial activity, have been fabricated by facile chemical route. The structural properties of the nanomaterial were thoroughly characterized by SEM, TEM, EDX, HRTEM, STEM-HAADF, elemental profiling, XRD and Raman spectroscopy, while the optical and photocatalytic properties were studied by UV-vis absorption spectroscopy. TEM and FESEM showed nanorods with average width and length as 80[Formula: see text]nm and 178[Formula: see text]nm. XRD showed wurtzite ZnO with 27[Formula: see text]nm crystallite size. PL analysis of ZnO nanorods showed peaks at 415[Formula: see text]nm, 439[Formula: see text]nm, 499[Formula: see text]nm and 561[Formula: see text]nm. The fabricated ZnO nanorods exhibited extremely enhanced photocatalytic performance with very high rate constant of 0.201[Formula: see text]min[Formula: see text] for degradation of organic pollutant MB in water under only 15[Formula: see text]min of solar exposure. ZnO nanorods completely inhibited growth of Bacillus oceanisediminis and Escherichia coli at 500[Formula: see text][Formula: see text]g/mL and 700[Formula: see text][Formula: see text]g/mL, respectively. The origin of antibacterial behavior of ZnO nanorods against B. oceanisediminis and E. coli has been investigated using histidine for scavenging ROS, morphological change by SEM and agarose gel electrophoresis. Our results showed that ROS-induced oxidative stress damages cell wall, evident from SEM, and leads to fragmentation of DNA both of which contribute to the antibacterial action of ZnO nanorods. The tentative mechanism of extremely strong photodegradation performance of ZnO nanorods has also been proposed.

Investigation of Evaporation Rate for Covered and Uncovered (using recycled materials) Conditions in UiTM Shah Alam

The evaporation rate varies according to temperature, humidity, and wind. The evaporation rate tends to be higher in the hot, dry months and lower in the wetter ones. This may affect the nation’s energy use, indoor air quality, and water availability. This study conducted experiments under three conditions—uncovered, partially, and fully covered to ascertain the evaporation rate at UiTM Shah Alam, Malaysia. Recycled materials such as bottle caps were used in the experiment. The study examined the evaporation rate at UiTM Shah Alam in Selangor. The study discovered that the uncovered surface area evaporated at the highest rates in the morning, noon, and afternoon due to direct solar exposure. As some or all of the surface was shielded from the sun’s rays, partially covered and fully covered surface areas had lower evaporation rates. It shows the evaporation rate for fully covered condition reduced 22 – 50 percent from uncovered condition. Meanwhile, evaporation rate for partially covered condition decreased by 10 – 17 percent compared to uncovered condition. The study offers important information about the variables influencing evaporation rate, which can be used to enhance understanding of evaporation processes and optimize evaporation in various applications. The findings may shed important light on the evaporation process and the variables that influence it, such as temperature, humidity, and cover material. The research results can be used to enhance building design and construction methods, increase building energy efficiency, and guide water management and conservation policies.

Thermotolerance capabilities, blood metabolomics, and mammary gland hemodynamics and transcriptomic profiles of slick-haired Holstein cattle during mid lactation in Puerto Rico

Holstein cattle carrying a prolactin receptor gene mutation (SLICK) exhibit short and sleek hair coats (short-haired Holstein [SLK]) enhancing thermotolerance and productivity compared with wild type-haired Holstein (WT) under tropical conditions. The objectives were to unravel the physiological and molecular mechanisms that confer an advantage to this slick genotype in Puerto Rico and determine potential correlations between metabolites and physiological variables. At 160 ± 3 DIM we compared vaginal temperatures (VT) and voluntary solar radiation exposure (VSRE) during 48 h between 9 SLK and 9 WT Holsteins, whereas a subsample of 7 SLK and 7 WT were used to assess udder skin temperature, mammary gland hemodynamics and transcriptomics, and blood plasma untargeted metabolomics at a single time point. The SLK cattle showed lower VT throughout the day and greater VSRE at 1000 h and 1100 h compared with their WT counterparts. Total mammary blood flow (MBF) was greater in SLK Holsteins compared with WT. The metabolite 9-nitrooctadecenoic acid was identified as a potential biomarker for MBF; moreover, SLK cattle had greater amounts of this metabolite in their plasma. Prostaglandin D2 synthase (PTGS) was upregulated in the slick mammary gland, while plasma prostaglandin D2 was positively correlated with milk yield and increased in SLK Holsteins compared with WT. Interestingly, the arachidonic acid metabolism pathway was enriched in the mammary gland transcriptome and perturbed in the blood metabolome in the SLK Holsteins. In conclusion, SLK Holsteins exhibited lower body temperatures, greater VSRE, enhanced blood supply to the mammary gland, and alterations in genes and metabolites involved in arachidonic acid metabolism at the mammary gland and blood plasma. The usage of the SLK Holstein cattle genetics in dairy operations could be a feasible alternative to mitigate the adverse consequences of heat stress.

Microwave Treatment of Three Different Types of Sewage Sludge Based on Their Solar Drying Exposure Time: Effect on Microorganisms, Water Content and Agronomic Aspects

This study aimed to treat sewage sludge through microwave irradiation at a laboratory scale. The objective was to investigate the effect of microwave irradiation on microorganisms, water content, organic matter, and agronomic nutrients present in sewage sludge. Three types of sewage sludges obtained from a full-scale wastewater treatment plant were considered: Sludge A (raw sludge), Sludge B (subjected to 15 days of solar exposure, achieving 48% dryness), and Sludge C (exposed to solar conditions and left open to the air for 23 months, reaching 94% dryness). These diverse sludges were exposed to microwave irradiation at various power levels (analysed variables: ε (Watts/g), θ (°C), T (min)). The specific exposure powers and temperature levels for the water reduction analysis were: 555, 955, 1355, and 1500 Watts/g and 55, 75, 95, and 105 °C, respectively. On the other hand, microbiological and agronomic nutrient analyses were conducted at 75 °C–1355 W and 95 °C–1355 W. After microwave exposure experiments, the results demonstrated the high effectiveness of microwave technology in eradicating indicator microorganisms of faecal contamination and reducing sludge volume while not affecting trace elements of significant agricultural value. The reduction in Escherichia Coli revealed that 4 min of irradiation was necessary to completely eliminate it to 0 ulog, indicating a 100% reduction, in Sludge A. In Sludges B and C, an additional 1 min was needed under conditions of 75 °C and 1355 W for a mass of 50 g. Moreover, Sludge A (46.27 × 105 or 4.80 ulog of dry matter), Sludge B (1.29 × 106 or 6.11 ulog of dry matter), and Sludge C (8.77 × 104 or 4.94 ulog of dry matter) were heavily contaminated with faecal coliforms. It took 6 min to reduce faecal coliforms to below the detection threshold.

Smart Flexible Porous Bilayer for All‐Day Dynamic Passive Cooling

Radiative cooling and evaporative cooling are sustainable cooling techniques without additional energy input. However, radiative cooling lacks dynamic cooling ability, while evaporative cooling demands external water replenishment, hindering their applications. Herein, a smart radiative/evaporative cooling bilayer combining a polydimethylsiloxane (PDMS) upper layer with a hydrogel lower layer is presented for efficient all‐day dynamic passive cooling. The PDMS layer with high solar reflectivity (0.930) and emissivity (0.952) provides excellent all‐day radiative cooling and protects the hydrogel from solar exposure, while the hydrogel layer demonstrates remarkable water evaporation and absorption, achieving dynamic evaporative cooling. Thus, the synergy of the two layers significantly enhances the overall cooling performance. Specifically, the bilayer can achieve the peak cooling power values of 424.4 and 650.6 W m−2 as well as the maximum subambient cooling temperatures of 10.4 and 3.7 °C during sunny and cloudy mid‐days, respectively. Moreover, the bilayer obtains 3.2 °C warmer temperature compared with the PDMS alone during cold nighttime, while the two structures exhibit comparable cooling performance during hot nighttime, indicating the self‐adaptive cooling property of the bilayer. In addition, the bilayer can achieve good cooling performance even under continuous cloudy days, offering a promising strategy for efficient all‐day dynamic passive cooling.

Quantitative optimization of the cooling performance of thermal-reflective coating on asphalt pavements

ABSTRACT Asphalt pavements are generally more susceptible to rutting under high temperatures, which can be further exacerbated by prolonged solar exposure and thermal absorption. The continuous thermal radiation from the asphalt pavement could aggravate the urban heat island effect and negatively impact urban life. To address this problem, this study was conducted to develop and evaluate a thermal-reflective coating material that minimizes thermal absorption and enhances the cooling effects of asphalt pavements. As documented herein, three pigment fillers were comparatively assessed in terms of their ability to enhance thermal reflectance, namely Hollow Glass Beads (HGB), Rutile Titanium Dioxide (RTD), and Potassium Titanate Whiskers (PTW). Acrylic resin (AR) and epoxy resin (ER) served as the base binding materials, while Polyamide acted as the curing agent. The performance of these materials was analyzed through various tests, including tensile strength, indoor cooling simulation, outdoor (field) cooling, and Differential Scanning Calorimetry (DSC)measurements. The corresponding results indicated that the optimum composition for the coating materials consist of: (1) base materials (namely 50% AR and 50% ER); (2) pigment fillers (namely 25% HGB, 20% RTD, and 15% PTW); and (3) curing agent (namely 40% Polyamide), with 2 mm as the optimum coating thickness to minimize thermal absorption.

Solar exposure, the melanocyte and melanoma: Survival pathways and molecular mechanisms.

The keratinocyte and the melanocyte, the main cellular constituents of the epidermis, are two very different cell types. Despite their different origins and functionality, they come together in the skin, synergistically, to function as a unit to control the adverse effects of solar exposure. The most significant element in this protective process is the ability of the melanocyte to produce melanin. This pigmented polymer is responsible for constitutive skin colour that plays a part in our identity as human individuals but more importantly, provides a tanning response. A change in pigmentation that provides both an immediate and prolonged protective effect from the damaging components of solar radiation. The melanocortin 1 receptor, a cell surface receptor on the melanocyte, receives paracrine stimulation in the form of hormonal communication from the keratinocyte, initiating a series of intracellular molecular interactions in the melanocyte, eventually involving transcription factors in the nucleus, most notably the microphthalmia-associated transcription factor, resulting in upregulation of enzymatic production of melanin and finally, its transfer back to the keratinocyte. The melanocortin 1 receptor is highly polymorphic and unfortunately this results in the Caucasians’ having constitutionally fairer skin combined with an incomplete tanning response, resulting in a higher susceptibility to skin cancer. The melanocyte is a relatively long-lived cell and over its extended life span can accumulate a series of mutational events. With malignant transition to melanoma this oncogenic baggage, when combined with antiapoptotic machinery that helps melanocyte survival, resulting in relatively rapid progression of the malignant process and contributing to its resistance to therapeutics.

Is Natural Solar Photolysis Effective for the Removal of Antibiotics and Pathogens from Waste Stabilization Pond?

This study aimed to investigate the occurrence of photolysis of two relevant antibiotics, sulfamethoxazole and trimethoprim, when present in a Waste Stabilization Pond and its disinfection under tropical irradiance. The influence of pH and matrix components, and the generation of photoproducts during solar exposure were evaluated. The pH-dependent speciation of antibiotics had a greater influence on the photolysis of antibiotics than the water matrix, with higher photodegradation at pH 4.1 than at pH 7.2. Trimethoprim was more susceptible to indirect photolysis, indicated by the steeper influence of the photosensitizers nitrate and humic acid compared to sulfamethoxazole. The photoproducts generated were persistent to photolysis and remained present in the samples up to 70 h irradiation. Wastewater disinfection was achieved after 70 h of solar exposure. Nonetheless, the exposure time required to remove at least 50% of sulfamethoxazole was on average 29 h and of trimethoprim 83 h, at the natural pH of the matrix (pH 7.2). Given that the residence time in Waste Stabilization Pond is 41 h, which corresponds to a maximum of 26 h solar irradiation, the exposure time in Waste Stabilization Pond is not sufficient to completely photodegrade antibiotics or disinfect the effluent, demanding further treatment.

SYNTHESIS, CHARACTERIZATION, AND PHOTOCATALYTIC PROPERTIES OF LANTHANIDE-DOPED HEMATITE NANOPARTICLES

This work aims to develop a highly efficient UV light-induced photocatalyst based on Sm-doped Hematite (α-Fe2O3) nanoparticles (NPs). Sm-doped α-Fe2O3 NPs were synthesized via a straightforward co-precipitation technique and subsequently analyzed for their morphological, structural, and functional attributes. Examination under scanning electron microscopy revealed the formation of NPs, often clustered in small aggregates. Transmission electron microscopy measurements indicated a NPs size range of approximately 18 nm. X-ray diffraction analysis confirmed octahedral-shaped with the crystalline nature and geometry of the synthesized NPs, with a determined crystallite size of 13 nm. The photocatalytic efficacy of the Sm-doped α-Fe2O3 catalysts was evaluated through their ability to degrade Rhodamine B (RhB) under solar light exposure. Remarkably, Sm-doped α-Fe2O3 exhibited outstanding degradation performance, achieving a 96.82% degradation of RhB within 120 minutes under specified conditions ((RhB) = 20 ppm; (catalyst) = 15-25-50 mg/L; pH = 7; T = 30 °C)). The degradation process followed pseudo-first-order kinetics. This exemplary photocatalytic activity suggests that the synthesized NPs hold significant potential for the efficient removal of organic pollutants from industrial wastewater.

Photo protection and its relationship with skin injuries in outdoor workers

Introduction: occupational and recreational activities are the most important causes of exposure to solar radiation, the cumulative effect of which could lead to the development of skin cancer.Objective: determine dermatological injuries associated with sun protection among outdoor workers in the Provincial Municipality of Huánuco in 2023.Methods: an analytical observational study of a census nature was carried out. The instrument used was validated through five expert evaluations, obtaining a Kappa index of 0,94. The reliability of the instrument was evaluated using the α-Cronbach coefficient of 0,68 and Kuder-Richardson 20 of 0,69. The sample included 300 subjects. The techniques used were behavioral observation, interviews and surveys. The statistical analysis consisted of the use of Chi2.Results: a statistically significant association (p < 0,05) was found between sociodemographic variables, hours of sun exposure, and sun protection practices. However, there was no association between dermatological injuries and sun protection practices in workers exposed and not exposed to solar radiation (p > 0,05).Conclusion: dermatological injuries were observed due to solar radiation exposure in both groups, including those engaged in outdoor activities and those with minimal sun exposure

Thermal energy storage materials designed from recycled Tetra Pak waste and paraffin waxes with enhanced photothermal conversion efficiencies

The phase change material (PCM)-integrated solar water heaters have great potential to save energy by utilizing renewable resources and to extend working hours even after sunsets. The PCM composites fabricated with recycled waste products lead to the circular economy which would contribute significantly to the sustainable development goals. In this work, Tetra Pak waste (TP) was used to prepare a form-stable PCM composite by mixing with paraffin wax (PW) and expanded graphite (EG) to integrate with solar water heaters. Two different PWs with melting points of 44 (RT44) and 64 (RT64) were used in the lower and higher temperature ranges of domestic water heating applications, respectively. The prepared composites exhibited enhanced thermal conductivity (1.1–1.15 W/m.°C), heat storage capacity (98.5–105.6 J/g), and photothermal conversion efficiency (85% and 55% for composites with RT44 and RT64, respectively). The numerical analysis conducted on a validated model helped to estimate the optimum composite thickness for specific solar exposure time. The fabricated PCM composite promoted the recycling of TP waste into useful products and was efficient in maintaining a higher nocturnal water temperature in the solar water heater.

UV irradiation behavior of Salix psammophila sand barriers in the process of desertification control.

Salix psammophila sand barriers degrade under sunlight exposure, resulting in diminished protective performance and shortened service life in desertification control. To address the unresolved issue of photoinduced damage and degradation in sand barriers, we conducted simulations to assess the accelerated damage effect of ultraviolet (UV) rays during solar exposure of S. psammophila sand barriers. Our analysis focused on elucidating the mechanism of UV irradiation in sand barriers by examining the structural and material property changes that occur during the degradation process. The results indicated the following: (1) The discoloration of sand barriers resulting from UV irradiation was primarily ascribed to the modification in lignin content. (2) The morphology and protective performance of S. psammophila sand barriers underwent significant changes following exposure to UV irradiation. The 96-day and 144-day time points of UV exposure are crucial for evaluating the extent of UV degradation in sand barriers. After 192 days of UV irradiation, there was a decrease in mass loss percentage by 3.62%, modulus of elasticity by 8.63%, and modulus of rupture by 6.74%. (3) The lignin, hemicellulose, and cellulose content decreased by 23.12%, 14.30%, and 6.96%, respectively. The impact of UV irradiation on the polysaccharide (cellulose and hemicellulose) in S. psammophila sand barriers was relatively minimal. (4) The carbon binding form in S. psammophila sand barriers underwent a transformation, characterized by a significant decrease in C1 content and an increase in C2 and C3 content. This resulted in a gradual enhancement of the oxidation state and binding energy of carbon. Therefore, to prolong the utilization lifespan of S. psammophila sand barriers, it is essential to address the UV irradiation behavior from the perspective of inhibiting lignin reactions.

Solar radiation stimulates release of semi-labile dissolved organic matter from microplastics

Microplastics can release dissolved organic matter (DOM) into seawater under solar radiation exposure. However, the molecular composition and bioavailability of this DOM remain to be investigated. Here, two popular microplastics, low-density polyethylene (LDPE) and polystyrene (PS), were exposed to solar radiation in an artificial seawater for 10 days. The solar-induced LDPE-DOM and PS-DOM were molecularly characterized using ultra-high-resolution mass spectrometry, and were further incubated in a coastal microbial assemblage to examine their bioavailability. Results showed that solar radiation stimulated release of DOM from the microplastics. Dissolved organic carbon concentration analysis indicated that approximately 19.03 µg C L–1 and 3.85 µg C L–1 were released from each gram of LDPE and PS per day, respectively. Molecular composition analysis showed that both the LDPE-DOM and PS-DOM comprised a proportion of nitrogen- and sulfur-bearing molecules, and that the LDPE-DOM molecules were associated with lower molecular abundance and values of double-equivalent-bond and aromatic-index, but higher average hydrogen-to-carbon ratio than that in the PS-DOM. In addition, a proportion of the assigned formulas in LDPE-DOM (22.3%) and PS-DOM (55.8%) could be found in a coastal-DOM sample, suggesting their potential contribution to coastal DOM pool. The further incubation experiment showed that nearly 18.7% of LDPE-DOM and 9.5% of PS-DOM were utilized or transformed within 30 days. Still, a fraction of the solar-induced LDPE-DOM and PS-DOM resisted rapid microbial utilization, remained as semi-labile DOM. These results underlined unaccounted consequences of microplastic-derived DOM in coastal DOM pool.

Evaluating Daylighting and Preservation in Heritage Halls: Shading Retrofit Case Study at Chengdu Jiangnan Pavilion Street Site Museum

Site museums, focusing on immovable relics, are crucial for preserving unearthed artifacts by controlling their microenvironment. Artifacts are typically found in air–soil coupled environments. Current environmental control standards, designed for artifacts preserved in air, lead to diseases in soil artifacts due to inappropriate storage conditions. Taking Chengdu’s Jiangnan Guan Street as a case study, this research, through monitoring the on-site artifact environment and analyzing the correlation between diseases and the environment, proposes a tensioned membrane sunshade for the protection of artifacts under exposed roofs. Utilizing computational fluid dynamics and lighting simulations, we compared the environmental changes before and after the implementation of the plan. The results indicate: (1) direct sunlight from the exposed roof is the main cause of instability and disease in the soil–air coupled environment of the artifacts; (2) the sunshade significantly improves the storage environment of the artifacts, reducing the temperature difference at various locations from 12.8 °C to 0.3 °C and decreasing direct solar exposure by over 90%. Our proposed solution effectively improves the preservation environment of unearthed artifacts, offering new insights for the protection of the Chengdu Jiangnan Pavilion Street site.

Setting up the ENVI-met digital tool to evaluate climatic conditions at an urban scale: a case study of Djelfa, Algeria

Urbanization has radically transformed natural landscapes, giving rise to complex urban environments worldwide. This transformation poses unique challenges in terms of climatic conditions. We emphasize the crucial importance of understanding urban microclimates shaped by geographical, architectural and human factors, requiring meticulous management for sustainable urban planning. These multifaceted factors interact to produce spatial variations in solar exposure, temperature and wind conditions, leading to distinct microclimatic pockets within cities. This underlines the imperative need for sustainable urban planning and design that takes account of their impact. Our field survey is located in Djelfa, Algeria, featuring a semi-arid to arid climate with continental influences. This article presents a methodology involving a detailed morphological analysis of the urban fabric, focusing on its structure, vegetation cover and spatial characteristics. It describes the use of ENVI-met, a powerful microclimate simulation tool offering a complete three-dimensional modeling system that integrates various urban elements, including buildings, streets and green spaces. Our spatial considerations guarantee model accuracy, with a rigorous geometry validation process maintaining model fidelity. The tool produces invaluable output data, including air temperature, relative humidity and thermal comfort indices. This paper emphasizes on the application of the model in Djelfa, Algeria, highlighting its potential in evaluating thermal condition in urban environments. The results of our study highlight significant temperature and humidity disparities between urbanized and green areas in the survey area, with temperature differences of up to 6°C during the day. Urbanized areas consistently have higher air temperatures and lower humidity levels, particularly during the day. Conversely, green spaces, including gardens and tree-lined areas, exhibit lower temperatures and higher humidity levels, offering valuable respite from heat stress. The use of the Physiological Equivalent Temperature (PET) index allows us to assess thermal comfort, revealing variations in heat stress levels across the urban landscape. This research highlights the crucial importance of integrating green infrastructure into urban planning to improve thermal comfort and livability in cities. Furthermore, our study reveals the value of advanced tools like ENVI-met in understanding urban microclimates and provides valuable information for sustainable urban development and climate adaptation strategies.

Enhancing freshwater production in solar distillation: Hemispherical absorber modification and reflectors integration

Solar distillers have been recognized as a potential solution to address water scarcity issues in both remote and urban areas. However, one of the challenges associated with solar distillers is their relatively low productivity. The objective of the study is to enhance the evaporation surface area and solar radiation exposure of the hemispherical distiller (HSS). So, the HSS was modified by installing hemispherical absorber inside it. The modified HSS was nominated by HAHSS. The study examines the impact of different absorber radii, specifically 35 cm, 30 cm, and 25 cm. Moreover, front and rear mirrors were employed to amplify the intensity of the radiation directed onto the hemispherical absorber, with particular emphasis on enhancing the radiation reaching the rear portion of the absorber. Also, the incorporation of PCM (Phase Change Material) combined with Ag (Silver) nanoparticles beneath the surface of the hemispherical surface, with a thickness of 2 cm. The results obtained that the distillate of the HAHSS and HSS was 8050 mL/m2.day and 4100 mL/m2.day, respectively. So, the HAHSS achieved a remarkable increase in productivity of approximately 96 % compared to the HSS. In addition, changing the absorber radius strongly affected the productivity rise of the HAHSS. So, using an absorber with a radius of 35 cm resulted in a distillate efficiency of 48.4 % and productivity rise of 96 %. While using an absorber with a radius of 25 cm was resulted in a distillate efficiency of 39.3 % and productivity rise of 36 %. Moreover, using reflectors increased the productivity of HAHSS by 160 % over that of HSS. Finally, the accumulated distillate for the HAHSS with reflectors and PCM + Ag and HSS was 11,400 and 4050 mL/m2.day, respectively with improvement percentage of approximately 181 % compared to the HSS.

A data-driven model on human thermophysiological and psychological responses under dynamic solar radiation

Excessive solar radiation can also cause thermophysiological and psychological discomfort in the human body. In real-world environments, solar radiation is highly variable. Moreover, the amount of solar radiation exposure that people receive due to their outdoor activities can have large fluctuation. The physiological and psychological responses of the human body under this dynamic solar radiation exposure are quite different from those under steady-state solar radiation exposure. Therefore, this paper studies the physiological and psychological responses of the human body under the condition of dynamic solar radiation through the method of field experimental research and explores the applicability of the existing indicators of PET and UTCI in the dynamic radiation environment. A novel recurrent neural network model was used to predict skin temperatures and thermal sensations, in which genetic algorithm was applied to tune hyper-parameters.It is noteworthy that both thermal sensations and skin temperatures at exposed body segments show a stronger correlation to solar radiation, while there exists a time lag between solar radiation and skin temperature when people are exposed to solar radiation. Compared with thermophysiological models (DTS), the GA-LSTM model has a better prediction accuracy in thermal sensations.