Sunlight Conditions Research Articles

Influence of cloudy and clear-sky partitions, aerosols, and geometry on the recent variability in surface solar irradiance components in northern France

Abstract. Surface solar irradiance (SSI) is a fundamental parameter whose components (direct and diffuse) and variabilities are highly influenced by changes in atmospheric content and scene parameters. The respective importance of cloudy-sky conditions and atmospheric aerosols on SSI evolutions is region dependent and only partially quantified. Here we provide a comprehensive analysis of SSI variabilities recorded in northern France, a region with extensive variability in sky conditions and aerosol loads. Through the application of automatic filtering methods to 1 min resolution SSI ground-based measurements over Lille, sky conditions are classified as clear-sky, 11 %; clear-sun-with-cloud, 22 %; and cloudy-sun situations, 67 % from 2010 to 2022, for which we analyze the statistics and variabilities in the global horizontal irradiance (GHI), beam horizontal irradiance (BHI), and diffuse horizontal irradiance (DHI). Coincident photometric measurements of aerosol properties and radiative-transfer simulations provide the means to conduct a multivariate analysis of the SSI observed trends and year-to-year evolutions and to estimate aerosol and cloud forcings under clear-sun conditions. The analysis of the record value of all-sky GHI in spring 2020 attributes 89 % of the changes to the exceptional sunlight conditions (57 % of clear-sun situations). It highlights also for that season the importance of solar zenith-angle changes, whose positive effects on clear-sun conditions surpass those due to aerosols. Our results show all-sky GHI and BHI positive trends of around +4.0 and +4.4 Wm-2yr-1, respectively, in both spring and summer, which are explained by more than 60 % by an increase in clear-sun occurrences of +1 % yr−1. Additional significant BHI increases under clear-sun conditions are mainly explained in spring by the negative trend in aerosol optical depth (−0.011 yr−1) and partly by angular effects in summer. Moreover, we find that clear-sun-with-cloud situations are frequently marked by irradiance enhancement due to clouds, with 13 % more GHI on a monthly average and 10 % additional diffuse proportion than in clear-sky situations. Under such conditions, clouds add on average 25 W m−2 of diffuse irradiance that sets the GHI at the remarkable level of pristine (aerosol-and-cloud-free) conditions or even higher, by more than +10 W m−2 in summer and for low aerosol loads. Overall, our results highlight the dominant and complex influence of cloudy conditions on SSI, which precedes or combines with that of aerosols and geometrical effects, and leads to a remarkable global level of SSI in clear-sun-with-cloud situations.

Kinetic study, byproducts characterization and photodegradation pathway of profoxydim in a biochar water soil system

The study focused on the photodegradation of profoxydim, a low-toxicity cyclohexanedione herbicide commonly used in rice crops, under simulated sunlight conditions. Profoxydim’s behavior in paddy field conditions is not well understood, and this research aimed to fill that gap, particularly examining the effect of commonly utilized organic amendments such as biochar (BC) on its degradation. Results indicated that profoxydim degrades rapidly, with a half-life of 2.4 ± 0.3 h in paddy water and 1.03 ± 0.1 h in paddy soil. However, when BC was introduced, the degradation slowed significantly, extending the half-lives to 3.1 ± 0.2 h in water and 3.07 ± 0.5 h in soil. The study identified five degradation products (DPs) using TOF mass accuracy measurements and MS/MS spectra fragmentation. Two of these DPs were found to be more stable than profoxydim itself. Additionally, the research proposed a novel photodegradation pathway, highlighting processes such as homolytic C-N bond cleavage, photoisomerization, and photoinduced oxidation. The study’s findings contribute new insights into the environmental fate of profoxydim, offering a deeper understanding of its transformation in rice paddy fields and aiding in the assessment of potential risks associated with its residues in agricultural environments.

Unveiling the potential of Cs2AgBiBr6 perovskites for next-generation see-through photovoltaics

Lead-free perovskite solar cells are strong contenders in the race for green and sustainable energy. Among these, cesium silver bismuth bromide (Cs2AgBiBr6) stands out, but its potential was hampered by the need for high-temperature processing, hindering its transition to scalable techniques. In this work, we present the feasibility of blade-coating deposition of Cs2AgBiBr6 layer. Thanks to the temperature control of the substrate during the process, we deposited uniform films at precise thickness enabling the fabrication of fully semitransparent devices with power conversion efficiencies (PCEs) of 3.07 % and 7.7 % under 1 sun and indoor light conditions, respectively. Furthermore, we evaluated important metrics for transparent photovoltaics such as Light Utilization Efficiency (LUE) and Color Rendering Index (CRI) of the devices by varying the Cs2AgBiBr6 thicknesses and the illumination conditions. The results showed LUEs at 1 Sun illumination of 1.1 % (1.5 %) and CRI of 71 (62.5) for 200 nm-thick and 400 nm-thick perovskite films, respectively. Finally, we evaluated the process scalability fabricating 6 cm2-sized semitransparent modules suitable for low-power electronics in Internet of Things field. This study opens the door to the development of non-hazardous, scalable, lead-free perovskite solar cells and modules suitable for integration into our everyday surroundings thanks to their see-through properties.

An Electron Bridge of Shared Atoms Mediated Cs3Bi2Br9/Bi2WO6 Z‐Scheme Heterojunction for Photocatalytic CO2 Reduction

AbstractConverting clean solar energy into chemical energy through artificial photosynthesis is an effective solution to solve the energy and environmental issues. Here, we report a Cs3Bi2Br9/Bi2WO6 (CBB/BWO) Z‐scheme heterojunction constructed via electrostatic self‐assembly, which facilitates efficient separation of photogenerated carriers and ensures the corresponding redox capacity of both components. By sharing Bi atoms, a Br−Bi−O bond is established between CBB and BWO, serving as an “electron bridge”. The electrons generated by BWO are efficiently channeled to CBB through the heterojunction‐formed “electron bridge”, thereby achieving effective photocatalytic CO2 reduction. Under simulated sunlight conditions, it exhibits the highest CO yield of 72.52 μmol g−1 (without the addition of any precious metal, photosensitizers or sacrifices), which is approximately 7‐fold and 18‐fold greater than that of pure CBB and BWO, respectively. This work provides a more profound comprehension of the regulation of electron transfer through interfacial chemical bonds, thereby proposing a promising strategy for the development of efficient heterojunction photocatalysts for CO2 photoreduction.

Performance of spherical and flat solar cells under different environmental conditions

This study investigates the performance degradation of spherical and flat solar modules due to dust accumulation. To isolate the effect of dust, both modules were subjected to identical environmental conditions, including irradiance, temperature, and humidity. The results reveal a significant reduction in power efficiency as dust density increases, with a nearly linear relationship observed. Spherical solar modules exhibited a minor decrease in efficiency (±3.64%) compared to flat solar modules (±5.46%) under increased dust density, consistent with prior research. Dust accumulation affects solar cells by causing dust deposition, light scattering, and temperature rise. Flat solar panels are more susceptible to dust accumulation due to their larger surface area, which attracts more dust particles. In contrast, spherical cells’ smaller surface area minimizes dust build-up, making them less prone to efficiency loss. The study also examined the impact of solar intensity and tilt angle on efficiency. Spherical cells demonstrated greater resilience in varying light conditions and tilt angles, maintaining efficiency across a wider range of scenarios than flat panels. These findings emphasize the importance of considering dust accumulation when designing and maintaining solar panels, with spherical modules offering advantages in dusty environments and under changing sunlight conditions.

Improved preservation of the color and bioactive compounds in strawberry pulp dried under UV-Blue blocked solar radiation

Strawberry (Fragaria ananassa spp.) is a highly preferred fruit because of its health benefits, flavor, fragrance, and color appeal. The drying process for strawberries extends their shelf life but also changes their color and alters their nutritional contents. The anthocyanins are responsible for the color, which are susceptible to degradation during thermal processing, reducing the customer appeal of these food products. The benefit of solar drying of strawberry pulp using UV-Blue blocking optical filters compared with d irect solar drying is presented in this work. Total anthocyanins, antioxidant activity, and the color of the strawberry pulp were monitored as the drying progressed. The UV-Blue blocking optical filter consisted of a copper sulfide/copper selenide thin film of 160 nm in thickness applied on the outer surface of cellular polycarbonate sheets of 8 mm cell-size, 0.1 mm wall thickness (1 kg/m2) cut from sheets measuring 122 cm x 122 cm in area, and protected by a food-safe adhesive polyethylene foil. Total anthocyanins and antioxidant activity were measured using the differential pH and the DPPH (2,2-diphenyl-1-picrilhydrazil) methods. The filter preserves a higher total anthocyanin content and antioxidant activity in the dried product than in the pulp dried under sunlight conditions. A reduced total color change was observed in the product dried under the UV-Blue blocking solar filter. This study highlights a general need to evaluate the bioactive merits of solar dried farm produce to assess the advantage they hold for their commercialization.

Photocatalytic Nanocomposite Based on Titanate Nanotubes Decorated with Plasmonic Nanoparticles for Enhanced Broad-Spectrum Antibacterial Activity.

Infections resulting from microorganisms pose an ongoing global public health challenge, necessitating the constant development of novel antimicrobial approaches. Utilizing photocatalytic materials to generate reactive oxygen species (ROS) presents an appealing strategy for combating microbial threats. In alignment with this perspective, sodium titanate nanotubes were prepared by scalable hydrothermal method using TiO2 and NaOH. Ag, Au, and Ag/Au-modified titanate nanotubes (TNTs) were prepared by a cost-effective and simple ion-exchange method. All samples were characterized by XRD, FT-IR, HRTEM, and DLS techniques. HRTEM images indicated that the tubular structure was preserved in all TNTs even after the replacement of Na+ with Ag+ and/or Au3+ ions. The antibacterial activity in dark and sunlight conditions was evaluated using different bacterial strains, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The results showed that while a low bacterial count (∼log 5 cells per well) was used for inoculation, the TNTs exhibited no antibacterial activity against the three bacterial strains, regardless of whether they were tested under light or dark conditions. However, the plasmonic nanoparticle-decorated TNTs showed remarkable activity in the dark. Additionally, Ag/Au-TNTs demonstrated significantly higher activity in the dark compared with either Ag-TNTs or Au-TNTs alone. Notably, under dark conditions, the Au/Ag-TNTs achieved log reductions of up to 4.5 for P. aeruginosa, 5 for S. aureus, and 3.7 for E. coli. However, when exposed to sunlight, Au/Ag-TNTs resulted in a complete reduction (log reduction ∼9) for P. aeruginosa and E. coli. The combination of two plasmonic nanoparticles (Ag/Au) decorated on the surface of TNTs showed synergetic bactericidal activity under both dark and light conditions. Ag/Au-TNTs could be explored to design surfaces that are responsive to visible light and exhibit antimicrobial properties.

Performance testing of an innovative integrated zenithal daylight guide with solar water heater under real-weather conditions

Zenithal Daylight Guides (ZDG) and Solar Water Heaters (SWH) are individual energy-saving solutions utilized across diverse building types. This study proposes an innovative integrated power-saving system, uniting ZDG and SWH into a single model. The integration concept is rooted in leveraging the available space surrounding the daylighting device's pipe to incorporate a solar heater via a serpentine collector. The primary aim of this amalgamation is to optimize solar energy savings, minimize spatial demands, and alleviate manufacturing expenses. Moreover, the impetus behind this study stems from the recent emergence of daytime power outages in Egypt, attributed to heightened consumption surpassing production capacities. The ZDG is still not well known in Egypt. This is the only study until the year 2022/2023 in Aswan, Egypt, that analyzes the performance of this device under extreme sunlight conditions (with maximum global illumination reaching approximately 118 Klux). Across various seasons, the lighting and thermal efficacy of the current model underwent experimental testing and analysis to assess its practical utility. The integrated system effectively elevated the water temperature and achieved adequate light transmission, as indicated by the obtained results. The average transmitted indoor illumination on the work surface reached approximately 2470 lux. The reliance on electrical lighting could be mitigated for up to 5 hours. On the other hand, the highest water temperature and maximum instantaneous efficiency reached are about 70°C and 37%, respectively. Throughout the experiments, the proposed solar heater achieved a maximum daily thermal efficiency of 31.5%. The findings are deemed satisfactory and promising.

Quantifying the sediment sorption of organic ultraviolet filter chemicals using solvophobic theory

Hydrophobic organic chemicals (HOCs) that enter the aquatic environment often negatively impact organisms, endangering aquatic biodiversity. Understanding sediment sorption equilibria for these chemicals can properly direct mitigation efforts. In addition, many HOCs of environmental concern lack sufficient environmental fate data to adequately assess their risk to ecosystems and humans. In this study, a sorption method addressing solvophobic effects was used to quantify the sorption of an HOC of current environmental concern, OD-PABA (padimate O, 2-ethylhexyl-4-(dimethylamino)benzoate), to a variety of sediments. OD-PABA is an organic ultraviolet filter chemical used in commercial sun protection products; it has been shown to exhibit cytotoxic effects and is known to photochemically transform under natural sunlight conditions. Given its commercial use, it enters the aquatic environment via recreational use and wastewater treatment plant effluent. OD-PABA is strongly hydrophobic; to mitigate the adsorption of OD-PABA to the container walls during sorption experiments, a precise concentration of methanol was used to avoid solvophobic effects. This sorption method was used to determine the sorption capacities for OD-PABA of four sediment samples, each with unique geochemical characteristics. Sediment-water distribution coefficients (Kd) were quantified and were normalized to various sediment characteristics to assess the main driving force(s) for sorption of OD-PABA. Organic carbon content was found to be a main driving force, with organic carbon-normalized distribution coefficients (log Koc) ranging from 4.4 to 4.6 for sediments with total organic carbon (TOC) > 10%); the clay fraction was also found to be important, especially for sediments with low TOC. The sorption of para-aminobenzoic acid (PABA), a water-soluble analog of OD-PABA was also investigated to assess the experimental approach, yielding a log Koc of 2.1 for the sediment with the greatest TOC.

Effect of Storage Conditions and Time on the Dimensional Stability of 3D Printed Surgical Guides: An InVitro Study.

To evaluate the dimensional stability over time of additively manufactured surgical templates, fabricated by different resins, and stored by different methods. Using a 3D printer with DLS technology and two different resins (Surgical Guide (SG)-WhipMix and Key Guide (KG)-KeystoneIndustries), 96 surgical guides were additively manufactured. The guides were stored in three different environments: directly exposed to sunlight (S1), in normal interior room conditions (S2), and in darkness (S3). The guides were digitally scanned immediately after fabrication and post-processing, and after 1, 3, and 6 months of storage. For each group, the mean deviation of the root mean square (RMS) between guide's intaglio surface, as well as the axial deviation between sleeves' housings were calculated. The mean axial variations of angular axis deviation of sleeves' housings ranged between 0.09° and 3.99°. The mean deviation of the RMS discrepancy in guide's intaglio ranged from 0.1 to 0.18 mm. Variations were significant (p < 0.001) only for the S1 group and only for SG material. After 3 months, an additional storage time of 3 months did not have any further effect on dimensional stability. Within the limitations of the present study, storage time of a surgical guide for up to 3 months after manufacturing, as well as printing material can significantly affect surgical guide's dimensional stability, when they are exposed to direct or indirect sunlight conditions. Storage of guides in a dark environment is recommended in order to avoid an additional source of error in computer-guided surgery workflows.

Physiological characteristics of ornamental caladiums (Caladium x hortulanum Birdsey, Araceae Juss.) through leaf colour diversity

This work aims to analyze the physiological characteristics of caladium ornamental plants with different leaf colors. Ten leaf colors, i.e., dark maroon, maroon, red, pink, white, pinkish young green, yellow, lime green, pinkish dark green, and dark green, were arranged in a completely randomized design and subjected to colorimetric red–green–blue (RGB) and portable photosynthesis measurement. Caladium leaf color, defined by the colorimetric RGB value, significantly impacted leaf physiological properties. Heatmap analysis apparently clustered caladiums into dark-colored group and light-colored ones. Dark-colored caladiums, as indicated by lower RGB values, exhibited higher photosynthesis rate, stomatal conductance, and water use efficiency (WUE). In contrast, light-colored caladium show a higher RGB, leaf temperature and light use efficiency (LUE) than the dark ones. By considering their leaf color-based physiological adaptability, this work recommends moderate sunlight and adequate water conditions for growing light-colored caladiums, while dark caladiums potentially tolerate excess light and water scarcity. Further research, including quantitative pigment analysis, is necessary to verify this hypothesis.

Design and Preliminary experiment of an Off-axis aequilate-mirrors linear Fresnel concentrator with sunlight self-adaptive feature

The Off-Axis Linear Fresnel Reflector (LFR) is an innovative, compact solar concentrator designed to reduce device height and wind-load without compromising efficiency. It is crucial in applying LFR devices to applications such as building façades. To this aim, The Off-axis LFR design is introduced to addressing the inter-mirror blocking issue that diminishes the efficiency of conventional LFRs. Initially, an optimized Aequilate-mirrors design was proposed to reduce manufacturing complexity and cost. Subsequently, a crank-slider mechanism was introduced as a solution to the issue of inconsistent angle adjustment among the mirrors. Additionally, the paper details the sunlight self-adaptive feature of the Off-axis LFR concentrator, where the LFR mirrors can independently rotate to track the sun’s position, adaptively altering the mirror array’s profile and sunward aperture. This feature maximizes the device’s sunlight harvesting capacity, particularly in angled sunlight conditions. A prototype of the Off-axis LFR device was designed and built for assessment, featuring a focus length of just 78 mm and an overall 145 mm housing height. The paper then discusses how the sunlight self-adaptive features enhance the efficiency during the early morning and twilight hours. Comprehensive testing, including mechanical driving, laser focusing, and outdoor full-function verification, was conducted. Ultimately, comparative photo-thermal efficiency tests with a similarly sized conventional LFR concentrator demonstrated that the Off-axis LFR concentrator could achieve a significant increase in efficiency, with an all-day average thermal efficiency improvement of over 10 %. Based on the previous theoretical study, this study has completed the engineering prototype design and validation. And confirmed a thermal concentration efficiency of 44.36 % within a height of 145 mm in experiments.

Using the Groundwater Cooling System and Phenolic Aldehyde Isolation Layer on Building Walls to Evaluation of Heat Effect

This study examines the thermal performance of building walls under full sunlight conditions using various insulation strategies. Specifically, it evaluates: (1) the effects of heat on building walls and indoor spaces; (2) the impact of groundwater cooling systems on thermal environments; (3) the influence of phenolic aldehyde insulation layers on heat transfer; and (4) the combined effects of groundwater cooling and phenolic aldehyde thermal insulation. Fluent–CFD (Computational Fluid Dynamics) was used in the study to simulate temperature transmission between the sun, the groundwater cooling system, and both indoor and outdoor spaces. Experimental analysis and simulations reveal that both the phenolic aldehyde insulation layer and the groundwater cooling system effectively reduce heat transfer, with the groundwater cooling system demonstrating the most significant impact. The phenolic aldehyde layer decreases the temperature difference between inner and outer walls by approximately 8 °C. The groundwater cooling system further reduces both inner and outer wall temperatures, helping to maintain cooler indoor environments. Simulation results indicate that, while the phenolic aldehyde layer effectively prevents external heat from penetrating into the room, it does not eliminate heat accumulation. In contrast, the groundwater cooling system efficiently dissipates heat, mitigating this issue. Groundwater analysis shows that maximum temperature differences occur at specific times of the day, with water flow effectively cooling the space. The combined use of the phenolic aldehyde insulation layer and the groundwater cooling system offers superior thermal performance. The phenolic layer provides effective heat blocking, while the groundwater system facilitates heat dissipation, optimizing indoor temperature and reducing air conditioning loads. This combination enhances overall comfort and energy efficiency, with the groundwater cooling system benefiting from reduced flow velocity and lower energy consumption.

Integrating machine learning with experimental investigation for optimizing photocatalytic degradation of Rhodamine B using neodymium-doped titanium dioxide: a comprehensive approach with toxicity assessment.

In this study, neodymium-doped titanium dioxide (Nd-TiO2) nanoparticles were synthesized via a hydrothermal method for the photocatalytic degradation of Rhodamine B (RhB) under UV and sunlight conditions. The properties of these NPs were comprehensively characterized. And optimization of RhB degradation was conducted using control-variable experiment and artificial neural networks (ANN) under various operational conditions and in the presence of competing compounds. The acute toxicity of both NPs, RhB, and the environmental impact of the photocatalytic treatment effluent on Danio rerio were evaluated. The Nd modification increased the catalyst's specific surface area and thermal stability. X-ray diffraction confirmed the tetragonal anatase phase in undoped TiO2, while Nd-doped TiO2 exhibited shifts in peaks and the presence of brookite and rutile phases. Nd (1mol%) doped TiO2 demonstrated superior RhB photocatalytic degradation efficiency, achieving 95% degradation and 82% total organic carbon (TOC) removal within 60min under UV irradiation. Optimization under sunlight conditions yielded 95.14% RhB removal with 0.28g/L photocatalyst and 1% doping. Under UV light, 98.12% RhB removal was optimized with 0.97% doping, along with the presence of humic acid and CaCl2. ANN modeling achieved high precision (R2 of 0.99) in modeling environmental photocatalysis. Toxicity assessments indicated that the 96-h LC50 values were 681.59mg L-1 for both NPs, and 23.02mg L-1 for RhB. The treated dye solution exhibited a significant decline in toxicity, emphasizing the potential of 1% Nd-TiO2 in wastewater treatment.

Comparison of the Energy Efficiency of Fixed and Tracking Home Photovoltaic Systems in Northern Poland

The relevance of the article’s results lies in presenting the actual energy yields of PV panels of various generations and types of installations. The aim of the article is to provide answers about the effective operation of three different photovoltaic systems: a stationary off-grid system operated for several years, a stationary on-grid system, and a system mounted on trackers. A stationary on-grid system was used as the reference system, taking its area and energy yield as the reference point. The assessment was made on the basis of energy and cost efficiency analysis using the comparative method. The obtained results were compared to the results of other PV systems whose parameters were obtained from literature analysis. The analysis showed significant differences in adapting them to different sunlight conditions. The results confirmed the validity of using fixed PV panels (Installation II) in the short term and the advantage of the PV panel tracking system (Installation III) in the long term. The results also confirm that Installation I, despite its eight years of operation time, shows a relatively small decrease in efficiency, which confirms the validity of the long-term operation of the PV installation.

High‐Speed Flexible Near‐Infrared Organic Photodetectors for Self‐Powered Optical Integrated Sensing and Communications

AbstractIntegrated sensing and communications (ISAC) based on radio frequency (RF), merging the sensing and communication functionalities into a single platform, can effectively address the increasing demand for spectrums due to the proliferation of wireless devices. However, the ISAC commonly suffers from spectrum scarcity, high power consumption, and limited sensing capabilities. Here flexible self‐powered optical ISAC (O‐ISAC) is proposed and fabricated by preparing a high‐speed near‐infrared organic photodetector (NIR OPD) that exhibits a broad photodetection ranging from 300 to 1100 nm, specific detectivity over 1013 Jones, and −3 dB cutoff frequency over 1 MHz (λ = 1050 nm) in self‐powered mode, ranking as the fastest among self‐powered NIR OPDs in the region above 1000 nm. The device is fabricated by incorporating a narrow‐bandgap non‐fullerene acceptor BTPSV‐4Cl into the PCE‐10:BTPSV‐4F system to finely tune the film morphology and reduce trap states and energetic disorder. The semitransparent and regular NIR OPDs are integrated on one substrate to fabricate flexible O‐ISAC, realizing simultaneous accurate vital signs monitoring and high‐speed data transmission under ambient, sunlight, and NIR lighting conditions. It is envisioned that the proposed O‐ISAC will inspire a new generation of wireless technology to address RF limitations for emerging applications, such as intelligent healthcare, autonomous vehicles, and security.

Construction of ZnCo2O4/Ag3PO4 composite photocatalyst for enhanced photocatalytic performance

AbstractIn this study, ZnCo2O4/Ag3PO4 composite catalyst was prepared by the precipitation method, and their performance in the photocatalytic degradation of methyl orange (MO) was studied. The catalysts were characterized by scanning electron microscopy, high‐resolution transmission electron microscopy, X‐ray diffraction, energy‐dispersive X‐ray spectroscopy, selected area electron diffraction, X‐ray photoelectron spectroscopy, and UV‐Vis diffuse reflectance spectroscopy. The results indicate that the 0.1 ZnCo2O4/Ag3PO4 composite system has good photocatalytic activity in the degradation of methyl orange. Under simulated sunlight conditions, the degradation rate can reach 94% after 30 min. The maximum reaction rate constant of 0.1 ZnCo2O4/Ag3PO4 was 0.05301 min−1, which is 3 times and 52 times the rate constant of pure Ag3PO4 and pure ZnCo2O4, respectively. In catalyst recycling experiments, 0.1 ZnCo2O4/Ag3PO4 still degraded methyl orange at a rate of 84.4% after three cycles. Trapping experiments showed that holes and superoxide radicals mostly contributed to the photocatalytic degradation of methyl orange by the catalyst, while hydroxyl radicals played a partial role. The energy level structure of ZnCo2O4/Ag3PO4 is conducive to the effective separation of photogenerated electrons and holes, improving the lifespan of photogenerated charges. In the investigated catalyst series, 0.1 ZnCo2O4/Ag3PO4 demonstrated the best photocatalytic performance.

Deep learning for retrieving omni-directional ocean wave spectra from spaceborne synthetic aperture radar

Synthetic Aperture Radar (SAR) is a unique remote sensing instrument imaging ocean surface waves in two dimensions with high spatial resolution regardless of sunlight and weather conditions. However, due to the nonlinear imaging process, the ocean wave spectra cannot be retrieved directly from SAR data. The emergence of deep learning (DL) techniques provides a new paradigm for addressing this challenge. In this paper, a deep-learning-based model, called Wave-Spec-CNN, is proposed for retrieving omni-directional ocean wave spectra from SAR data. This model is constructed using approximately 21,000 collocations of Sentinel-1 Interferometric Wide swath mode images matched with global in-situ buoy data. The model adapts the convolution neural network (CNN) to accommodate the multi-valued nature of omni-directional ocean wave spectra, enhances performance by integrating a calibration branch and further incorporates physical characteristics into the training process. The results demonstrate consistency with buoy measurements for significant wave height (SWH) in the range of 0.5 m to 6 m, yielding a root-mean-square error (RMSE) of 0.51 m on the validation dataset, comparable to traditional physical-based methods. In terms of mean wave period (MWP) and peak frequency (PF), the achieved RMSEs are of 1.24 s and 0.03 Hz, respectively. The retrieved omni-directional ocean wave spectra also allow to separate swell and windsea components for respective comparisons with those derived by in-situ buoy data. The RMSEs of respective SWH comparisons are of 0.46 m and 0.42 m. This research represents an initial endeavor into utilizing DL for the long-standing challenge of SAR inversion for ocean wave spectra, as well as providing valuable insights for employing DL in multi-parameter inversion tasks in remote sensing.

Superhydrophobic Composite Coatings Can Achieve Durability and Efficient Radiative Cooling of Energy-Saving Buildings.

Passive daytime radiative cooling (PDRC) technology has received a great deal of attention in the field of energy efficiency and environmental protection as a sustainable technology and a large-scale and promising solution to mitigate the environmental impact of global warming. In this study, we prepared PDRC material by combining FEP with modified Al2O3 particles and using the method of spray combined with phase separation. The synergistic effect of the formed surface micronanostructures, combined with the molecular vibration of FEP and the phonon polarization resonance of Al2O3, further improves the optical performance of the PDRC coating. The PDRC coating has an average reflectivity of 0.96 in the solar spectral band (0.3-2.5 μm) and an average emissivity of 0.963 in the atmospheric window band ((8-13 μm). In addition, the PDRC coating had good hydrophobicity, and its water contact angle (WAC) reached 159.3°. Under direct sunlight conditions, PDRC materials have a good temperature drop (4.9 °C) compared to ambient temperatures and radiative cooling power (81.2 W/m2). The prepared coating maintains superhydrophobicity and excellent cooling performance when soaked in solutions of different pH values and UV radiation, which was of great significance for sustainable applications. Our work provides a form of long-term cooling that can be effectively implemented in green and energy-efficient buildings.

Development of a new test design to investigate the degradation of pesticides in soil under sunlight conditions

Pesticides applied to soil surface are subject to photodegradation if the parent molecule is sensitive to UV-light absorption. Photodegradation studies are therefore mandatory for the registration of plant protection products to provide data on the degradation rate and on the nature of photoproducts formed. In general, sunlight is simulated in these studies with xenon lamps, e.g., a Suntest® device. Surface application on very thin soil layers followed by direct irradiation is common practice, but the control of the boundary conditions, i.e. soil temperature and moisture, to maintain the structure and viability of the soil is challenging. A homogeneous and stable soil microclimate is crucial to compare the degradation data of the test item from the irradiated soil samples to the dark controls as well as to the results from the aerobic soil metabolism study. After trying different scale-up test systems with the UV-sensitive herbicide imazamox as comparative test item, a new soil photolysis test system was developed which is manageable in the laboratory and enables a more favorable management of the boundary conditions, especially with regard to the soil moisture and temperature. For this, the solar simulator SolarConstant® 1200, equipped with metal halide lamps Radium HRI-TS 1000W/D/S/PRO, was installed by Atlas Ametek (Germany) in a temperature controllable walk-in incubation chamber with aluminum racks and reflectors to minimize diffuse light and to maintain a homogenous temperature of 22(± 1)°C within the irradiated soil. Borosilicate glass vessels with an inner diameter of 10 cm and a maximum height of 9 cm, covered by quartz glass, were used for the incubation of the applied soil under light. Contrary to the imazamox degradation half-lives obtained with the Suntest® test system, where an unusual slower degradation was observed under light compared to the dark controls, the results from the new SolarConstant® study design showed the expected faster degradation under light. Hence, it can be concluded that the experimental boundary conditions of the new test system are more suitable to maintain the viablity of the irradiated soil. Since no adjustments of the soil water content were needed, compared to daily water adjustments for thin soil layers incubated under a Suntest®, drying–wetting cycles are eliminated and microbial-induced soil processes are maintained.