Search Results (115)

Titanium dioxide (TiO₂) has been widely used as a potential candidate for the production of green hydrogen using the artificial photosynthesis approach. However, the wide bandgap (∼3.3 eV) of anatase TiO₂ makes it difficult to absorb a large fraction of the solar radiation reaching the Earth, thus providing a low photocatalytic activity. Anatase TiO₂ absorbs only 4% of solar radiation, which can be improved by engineering its bandgap to enhance absorption in the visible region. In the literature, many strategies have been adopted to improve the photocatalytic activity of TiO₂, such as metal and non-metal doping and heterojunctions. These techniques have shown incredible enhancement in visible light absorption and improved photocatalytic activity due to their ability to lower the bandgap of pure TiO₂ semiconductors. This review highlights different techniques like doping, heterojunctions, acidic modification, creating oxygen vacancies, and temperature- and pressure-dependence, which have improved the photochemical response of TiO₂ by improving charge-transfer efficiencies. Additionally, the charge-transfer mechanism and enhancement in the photochemical response of TiO₂ is discussed in each portion separately. Full article

Irrigation management in areas affected by climate change requires an accurate determination of transpiration losses in crops, such as grapevines. The existing literature has primarily focused on estimating transpiration losses based on two critical microclimate factors: vapor pressure deficit (VPD) and solar radiation intensity (R_s). However, most studies have been conducted under abundant soil water availability conditions, whereas research under limited water availability remains scarce. Thus, this study aims to develop models capable of accurately determining transpiration losses of grapevines under both full irrigation and limited soil water conditions. Sap flow sensors using the heat ratio method were employed to measure transpirational losses. These measurements were compared with the results from the models afterward. The results suggest that VPD was the dominant factor affecting canopy conductance, which decreased exponentially as VPD increased. Furthermore, a piecewise linear regression analysis revealed a threshold value for Rs during both study years. This finding suggests that Rs impacts transpiration losses in two distinct ways, highlighting the necessity to develop two separate models for determining transpiration losses each study year. The estimation capability of the models was verified using the k-fold cross-validation method, suggesting that reliable predictions can be made under both well-watered and rainfed conditions. Full article

This study aimed to understand the difference in forest transpiration (T) between slope positions and to separate the contributions of main influencing factors to improve the accuracy of forest transpiration estimation at the slope scale by up-scaling the results measured at the plot scale, especially in semiarid regions with significant soil moisture differences along slope positions. Two plots of larch plantation were established, one at the lower position and another at the upper position of a northwest-facing slope in the semiarid area of the Liupan Mountains in northwest China. The sap flow velocity ($J_S$, mL·cm⁻²·min⁻¹) of sample trees, meteorological parameters in the open field, and soil water potential in the main root zone (0–60 cm) were monitored simultaneously in the growing season (from July to September) of 2015. However, only the transpiration data of 59 selected effective days were used, after excluding the days with rainfall and missing data. Based on the relative sap flow velocity (the ratio of instantaneous sap flow velocity to its daily peak value), the impacts of terrain shading and soil water potential on sap flow velocity at varying slope positions were quantitatively disentangled. The reduction in $J_S$ at the lower slope plot, attributed to terrain shading, exhibited a positive linear correlation with solar radiation intensity. Conversely, the $J_S$ reduction at the upper slope plot demonstrated a quadratic functional relationship with the differential in soil water potential between the two plots. Subsequently, employing the relationship whereby transpiration is equivalent to the product of sap flow velocity and sapwood area, we conducted a quantitative analysis of the contributions of soil water potential, sapwood area, terrain shading, and their interaction to the disparity in transpiration between the two slope positions. The total transpiration of the 59 effective days was 41.91 mm at the lower slope plot, slightly higher than that at the upper slope plot (37.38 mm), indicating a small difference (4.53 mm) due to the offsetting effects of multiple factors. When taking the upper slope plot as a reference, the plot difference in soil water potential increased the total transpiration for the 59 days at the lower slope plot by 16.40 mm, while the differences in sapwood area and terrain shading and the interaction of the three factors decreased the total transpiration at the lower slope plot by 6.61, 2.86, and 2.40 mm, respectively, making a net increase of 4.53 mm. Based on the pilot study under given conditions of location, soil, climate, and vegetation, the contributions of the influencing factors to the stand transpiration differences between the upper and lower slopes are as follows: soil moisture (soil water potential) > stand structure (sapwood area) > solar radiation (terrain shading) > interaction of all factors. All these impacts should be considered for the accurate prediction of forest transpiration at the slope scale through up-scaling from measurement at the plot scale, especially in semiarid regions. Full article

Land surface reflectance is a basic physical parameter in many quantitative remote sensing models. However, the existing reflectance conversion techniques for drone-based (or UAV-based) remote sensing need further improvement and optimization due to either cumbersome operational procedures or inaccurate results. To tackle this problem, this study proposes a novel method to mathematically implement the separation of direct and scattering radiation using a self-developed multi-angle light intensity device. The verification results from practical experiments demonstrate that the proposed method has strong adaptability, as it can obtain accurate surface reflectance even under complicated conditions where both illumination intensity and component change simultaneously. Among the six selected typical land cover types (i.e., lake water, slab stone, shrub, green grass, red grass, and dry grass), green grass has the highest error among the five multispectral bands with a mean absolute error (MAE) of 1.59%. For all land cover types, the highest MAE of 1.01% is found in the red band. The above validation results indicate that the proposed land surface reflectance conversion method has considerably high accuracy. Therefore, the study results may provide valuable references for quantitative remote sensing applications of drone-based multispectral data, as well as the design of future multispectral drones. Full article

There is a difficulty in survey sampling when non-response (NR) occurs in the process of estimating the population parameters. This study examines the effectiveness of combined and separate log-type estimators when using bivariate auxiliary information when NR occurs in data. In this study, we propose families of novel log-type estimators under various scenarios. We performed an analysis on the reliability and efficiency of our proposed estimators in situations when NR occurs in both study and auxiliary variables and when NR occurs only in study variables. In this study, we have concentrated on certain issues like how the non-response effects the estimators’ efficiency, how different NR rates effect the precision of estimators, and how the combined and separate types of estimators handle the problem of NR. We proved the efficiency of our proposed estimators by using the bias and mean square error (MSE) metrics under different NR rates, illustrating the positive correlation between higher NR rates and increased errors. To evaluate the impact of NR on MSE values, we took four real datasets, which included a cost of living index dataset for 121 nations and another dataset which is essential for forecasting solar UV radiation hazards influenced by environmental factors, thus enhancing public health awareness and preventive strategies. Additionally, a simulation study comprising 10,000 iterations was also performed. This study provides survey practitioners with valuable guidance on selecting strong estimation methods to enhance the accuracy and efficiency of survey estimates in the context of non-response. This investigation contributes to the domain of survey sampling by demonstrating the robustness and effectiveness of log-type estimators. These estimators enhance survey findings by effectively addressing NR issues. Full article

Radiative cooling is a passive cooling strategy that dissipates heat externally through the atmospheric window (8–13 μm). This study presents a radiative cooling film with a simple and cost-effective fabrication process. The film was fabricated by mixing SiO₂ hollow microspheres with a UV-curable resin, employing a photopolymerization-induced phase separation method. The resulting gradient refractive index structure enhanced thermal radiation emissivity. At an optimal silica-to-resin mass ratio of 1:1.5 and a film thickness of 1.1 mm, the film achieved a solar reflectivity of 85% and an emissivity of 91% within the atmospheric window. Outdoor experiments conducted in both summer and winter demonstrated stable cooling performance. Under a solar irradiance of 796.9 W/m² (summer), the film reduced surface temperature by 10 °C compared to ambient air and 20 °C compared to an uncoated glass substrate, achieving a radiative cooling power of 76.7 W/m². In winter (solar irradiance of 588.8 W/m²), the film maintained a significant cooling effect, though with reduced efficiency due to lower solar exposure. Furthermore, long-term stability tests over six months showed that the film retained high solar reflectivity and infrared emissivity, indicating good durability. Overall, the developed radiative cooling films demonstrate excellent optical properties, structural stability, and cooling efficiency, making it a promising candidate for real-world radiative cooling applications. Further studies on environmental resilience and optimization under diverse climatic conditions are necessary for broader deployment. Full article

We hypothesize that predictable variations in environmental conditions caused by night/day cycles created opportunities and hazards that initiated information dynamics central to life’s origin. Increased daytime temperatures accelerated key chemical reactions but also caused the separation of double-stranded polynucleotides, leading to hydrolysis, particularly of single-stranded RNA. Daytime solar UV radiation promoted the synthesis of organic molecules but caused broad damage to protocell macromolecules. We hypothesize that inter-related simultaneous adaptations to these hazards produced molecular dynamics necessary to store and use information. Self-replicating RNA heritably reduced the hydrolysis of single strands after separation during warmer daytime periods by promoting sequences that formed hairpin loops, generating precursors to transfer RNA (tRNA), and initiating tRNA-directed evolutionary dynamics. Protocell survival during daytime promoted sequences in self-replicating RNA within protocells that formed RNA–peptide hybrids capable of scavenging UV-induced free radicals or catalyzing melanin synthesis from tyrosine. The RNA–peptide hybrids are precursors to ribosomes and the triplet codes for RNA-directed protein synthesis. The protective effects of melanin production persist as melanosomes are found throughout the tree of life. Similarly, adaptations mitigating UV damage led to the replacement of Na⁺ by K⁺ as the dominant mobile cytoplasmic cation to promote diel vertical migration and selected for homochirality. We conclude that information dynamics emerged in early life through adaptations to predictably fluctuating opportunities and hazards during night/day cycles, and its legacy remains observable in extant life. Full article

Solvents are particularly hazardous among the mixture of pollutants found in the air, as their low vapor pressure allows them to reach the atmosphere, causing damage to ecosystems, and producing secondary deleterious effects on living organisms through a wide variety of possible reactions. In response, innovative, sustainable, and ecological methods are being developed to recover solvents from industrial wastewater, which is typically contaminated with other organic compounds. This study describes the procedure for recovering acetone from a residue from the pharmaceutical industry. This compound contains a high amount of solid organic compounds, which are generated during the manufacture of medicines. The treatment consisted of performing a simple solar distillation using a single-slope glass solar still, which separated the acetone from the mother solution. Under ideal circumstances, the use of solar radiation allowed an efficiency rate of 80% using solar concentration by means of mirrors to increase the temperature and 85% without the use of mirrors in the production of distilled acetone, which was characterized to evaluate its quality using instrumental analytical techniques: NMR, IR, and GC. The results obtained indicate that the acetone recovered by this procedure has a good quality of 84%; however, due to this percentage obtained, its reuse is limited for certain applications where a high degree of purity is required, such as its reuse for pharmaceutical use; for this reason, it was proposed to use said compound to eliminate the organic impurities contained in the catalyst waste granules used in a Mexican oil refinery. The resulting material was examined by SEM and EDS, revealing a high initial carbon content that decreased by 29% after treatment. Likewise, as an additional study, a study was carried out to evaluate the characteristics of the residues obtained at the end of the distillation where rubidium, silicon, carbon, nitrogen, oxygen, and chlorine contents were observed. Full article

Near-infrared light-triggered photocatalytic water treatment has attracted significant attention in recent years. In this novel research, rational sonochemical fabrication of Ag₂S/g-C₃N₄ nanocomposites with various compositions of Ag₂S (0–25) wt% was carried out to eliminate hazardous rhodamine B dye in a cationic organic pollutant model. g-C₃N₄ sheets were synthesized via controlled thermal annealing of microcrystalline urea. However, black Ag₂S nanoparticles were synthesized through a precipitation-assisted sonochemical route. The chemical interactions between various compositions of Ag₂S and g-C₃N₄ were carried out in an ultrasonic bath with a power of 300 W. XRD, PL, DRS, SEM, HRTEM, mapping, BET, and SAED analysis were used to estimate the crystalline, optical, nanostructure, and textural properties of the solid specimens. The coexistence of the diffraction peaks of g-C₃N₄ and Ag₂S implied the successful production of Ag₂S/g-C₃N₄ heterojunctions. The band gap energy of g-C₃N₄ was exceptionally reduced from 2.81 to 1.5 eV with the introduction of 25 wt% of Ag₂S nanoparticles, implying the strong absorbability of the nanocomposites to natural solar radiation. The PL signal intensity of Ag₂S/g-C₃N₄ was reduced by 40% compared with pristine g-C₃N₄, implying that Ag₂S enhanced the electron–hole transportation and separation. The rate of the photocatalytic degradation of rhodamine B molecules was gradually increased with the introduction of Ag₂S on the g-C₃N₄ surface and reached a maximum for nanocomposites containing 25 wt% Ag₂S. The radical trapping experiments demonstrated the principal importance of reactive oxygen species and hot holes in destroying rhodamine B under natural solar radiation. The charge transportation between Ag₂S and g-C₃N₄ semiconductors proceeded through the type I straddling scheme. The enriched photocatalytic activity of Ag₂S/g-C₃N₄ nanocomposites resulted from an exceptional reduction in band gap energy and controlling the electron–hole separation rate with the introduction of Ag₂S as an efficient photothermal photocatalyst. The novel as-synthesized nanocomposites are considered a promising photocatalyst for destroying various types of organic pollutants under low-cost sunlight radiation. Full article

The negative effect of the operating temperature on the functioning of photovoltaic panels has become a significant issue in the actual energetic context and has been studied intensively during the last decade. The very high operating temperatures of the photovoltaic panels, even for lower levels of solar radiation, determine a drop in the open-circuit voltage, with consequences over the electrical power generated and PV-conversion efficiency. The temperature effect over the efficiency of monocrystalline and polycrystalline photovoltaic panels by using a double-climatic chamber and a solar simulation device was studied experimentally for two photovoltaic panels, one monocrystalline and another polycrystalline, with the same nominal power of 30 Wp. The double-climatic chamber used is composed of two separate rooms, a cold and a hot one, while the PV panel is placed as a barrier between them. The study is focused on establishing the effect of raising the temperature of PV panels over electrical parameters: voltage, current, and power produced and for efficiency and fill factor to promote sustainable energy consumption. The findings highlight the positive impact of cooling on enhancing system efficiency, with the primary focus on quantifying its overall performance. The operating temperature is controlled by the flow of air on the backside of the PV panel inside the cold room. The level of radiation studied corresponds to a vertical integration of PV panels in building façades. The coefficient of the mean variation of the efficiency with the photovoltaic panels’ temperature was −0.52%/°C; for voltage, −0.48%/°C, and for current, +0.10%/°C. Full article

The interest in alternative energy sources, including the use of solar radiation energy, is growing year by year. Currently, the most frequently installed photovoltaic modules are made of single-crystalline silicon solar cells (sc-Si). However, one of the latest solutions are perovskite solar cells (PSC), which are considered the future of photovoltaics. Therefore, the main objective of this research was to assess the environmental impact of the construction materials of monocrystalline and perovskite photovoltaic power plants toward their sustainable development. The research object was the construction materials and components of two 1 MW photovoltaic power plants: one based on monocrystalline modules and the other on perovskite modules. The life cycle assessment (LCA) method was used for the analyses. The IMPACT World+, IPCC and CED models were used in it. The analyses were performed separately for five sets of elements: support structures, photovoltaic panels, inverter stations, electrical installations and transformers. Two post-consumer management scenarios were adopted: storage and recycling. The life cycle of a photovoltaic power plant based on photovoltaic modules made of perovskite cells is characterized by a smaller negative impact on the environment compared to traditional power plants with monocrystalline silicon modules. Perovskites, as a construction material of photovoltaic modules, fit better into the main assumptions of sustainable development compared to cells made of monocrystalline silicon. However, it is necessary to conduct further work which aims at reducing energy and material consumption in the life cycles of photovoltaic power plants. Full article

Environmental problems associated with water pollution caused by organic dyes have raised serious concerns. In this context, photocatalytic processes have proven to be promising and environmentally friendly methods for water purification utilising abundant solar energy. In this study, a SrTiO₃-based photocatalyst was modified by doping with Al ions and the deposition of dual co-catalysts (Rh/Cr₂O₃ and CoOOH) to enhance the photocatalytic decomposition efficiency of methylene blue (MB). Pure perovskite SrTiO₃ was synthesised by chemical precipitation followed by calcination at 1100 °C. Al-doped SrTiO₃ with deposited co-catalysts showed 3.2 times higher photocatalytic activity compared to unalloyed SrTiO₃ with co-catalysts in MB decomposition under visible radiation. This study highlights the effectiveness of using dual co-catalysts and low-valence metal doping to enhance the efficiency of the photocatalytic decomposition of organic pollutants. The density functional theory analysis results show that the Al doping of SrTiO₃ improves charge separation and increases the lifetime of photogenerated electrons and holes while maintaining the size of the forbidden band, which confirms its effectiveness for enhancing photocatalytic activity. Full article

The production of cost-effective novel materials for PV solar cells with long-term stability, high energy conversion efficiency, enhanced photon absorption, and easy electron transport has stimulated great interest in the research community over the last decades. In the presented work, Cu/Cu₂S-MWCNTs nanocomposites were produced and analyzed in the framework of potential applications for PV solar cells. Firstly, the surface of the produced one-dimensional Cu was covered by Cu₂S nanoflake. XRD data prove the formation of both Cu and Cu₂S structures. The length and diameter of the one-dimensional Cu wire were 5–15 µm and 80–200 nm, respectively. The thickness of the Cu₂S nanoflake layer on the surface of the Cu was up to 100 nm. In addition, the Cu/Cu₂S system was enriched with MWCNTs. MWCNs with a diameter of 50 nm interact by forming a conductive network around the Cu/Cu₂S system and facilitate quick electron transport. Raman spectra also prove good interfacial coupling between the Cu/Cu₂S system and MWCNTs, which is crucial for charge separation and electron transfer in PV solar cells. Furthermore, UV studies show that Cu/Cu₂S-MWCNTs nanocomposites have a wide absorption band. Thus, MWCNTs, Cu, and Cu₂S exhibit an intense absorption spectrum at 260 nm, 590 nm, and 972 nm, respectively. With a broad absorption band spanning the visible–infrared spectrum, the Cu/Cu₂S-MWCNTs combination can significantly boost PV solar cells’ power conversion efficiency. Furthermore, UV research demonstrates that the plasmonic character of the material is altered fundamentally when CuS covers the Cu surface. Additionally, MWCN-Cu/Cu2S nanocomposite exhibits hybrid plasmonic phenomena. The bandgap of Cu/Cu₂S NWs was found to be approximately 1.3 eV. Regarding electron transfer and electromagnetic radiation absorption, the collective oscillations in plasmonic metal-p-type semiconductor–conductor MWCNT contacts can thus greatly increase energy conversion efficiency. The Cu/Cu₂S-MWCNTs nanocomposite is therefore a promising new material for PV solar cell application. Full article

To evaluate the contributions of different forcings to the temperature and atmospheric composition changes between 1980 and 2020, we exploited the chemistry-climate model (CCM) SOCOLv3. The study examined ozone content and atmospheric temperature response to (1) ozone-depleting substances; (2) greenhouse gas concentrations, ocean surface temperature, and sea ice coverage; (3) solar irradiance; and (4) stratospheric aerosol loading and, separately, (5) greenhouse gas concentrations, (6) ocean surface temperature and sea ice coverage, and (7) NO_x surface emissions. To evaluate the impacts of specific factors, we performed model runs driven by each factor (1–7) variability as well as a reference experiment that accounted for the influence of all factors simultaneously. We identified the relative contribution of different factors to the evolution of the temperature and ozone content of the lower troposphere and stratosphere from 1980 to 2020. The model results were in good agreement with the reanalyses (MERRA2 and ERA5). We showed that stratospheric ozone depletion before the Montreal Protocol introduction and partial recovery after that were chiefly driven by ODS. Stratospheric aerosol from major volcanic eruptions caused only short-term (up to 5 years) ozone decline. Increased greenhouse gas emissions dominate the ongoing long-term stratospheric cooling as well as tropospheric and surface warming. Solar irradiance contributed to short-term fluctuations but had a minimal long-term impact. Furthermore, our analysis of the solar signal in the tropical stratosphere underscores the complex interplay of solar radiation with volcanic, oceanic, and atmospheric factors, revealing significant altitudinal distributions of temperature and ozone responses to solar activity. Our findings advocate further innovative methodologies to take into account the nonlinearity of the atmospheric processes. Full article

Background/Objectives: The external environment constantly influences human health through many factors, including air quality, access to green spaces, exposure to pollutants, and climate change. Contamination poses a substantial threat to human well-being; conversely, environmental factors also positively impact health. The purpose of this study is to provide a comprehensive review of the complex relationship between various environmental factors and human health. While individual studies have explored specific aspects, a broader integrative understanding is lacking. Methods: Through databases (PubMed, Cochrane, Copernicus), 4888 papers were identified, with 166 selected for detailed analysis. Results: We summarized recent research, identifying multiple associations between environmental factors such as air pollution, climate change, solar radiation, and meteorological conditions and their impact on various health outcomes, including respiratory, cardiovascular, metabolic and gastrointestinal, renal and urogenital, neurological and psychological health, infectious and skin diseases, and major cancers. We use chord diagrams to illustrate these links. We also show the interaction between different environmental factors. Findings begin with exploring the direct impact of environmental factors on human health; then, the interplay and combined effects of environmental factors, elucidating their (often indirect) interaction and collective contribution to human health; and finally, the implications of climate change on human health. Conclusions: Researchers and policymakers need to consider that individuals are exposed to multiple pollutants simultaneously, the “multipollutant exposure phenomenon”. It is important to study and regulate environmental factors by considering the combined impact of various pollutants rather than looking at each pollutant separately. We emphasize actionable recommendations and solutions. Full article