Outdoor Sunlight Research Articles

A Study on the Performance of Soiled Solar Photovoltaic Panels at Different Tilt Angles in Al Seeb, Oman

Climate and weather conditions greatly affect photovoltaic (PV) module performance and efficiency, particularly in desert environments. Dust accumulation, which significantly reduces power generation efficiency, is currently the main issue facing photovoltaic modules since it affects the return on investment of PV systems. It is believed that the tilt angle of solar PV panels can be helpful in reducing the effect of soiling using the gravitational force experienced by the dust particles, mainly in dry environments. In this work, experimental studies were conducted to investigate the effects of the tilt angle and dust deposition on the electrical power generation performance of photovoltaic modules under weather conditions in Al Seeb, Oman. The study was conducted by exposing solar PV panels to outdoor sunlight for two weeks. Two of the PV panels with fixed and different tilt angles were cleaned on a daily basis, while another panel was left uncleaned. A comparison was made with the panel that was not cleaned for an extended time. Measurements included solar irradiance, solar panel temperature, voltage, and current. The output power and efficiency reached 93.5 W and 24.5%, respectively, for the panel cleaned daily. Furthermore, soiling resulted in an 18.8% power loss. The results showed that the highest output power of 79.75 W was observed at an angle of 25°, with an efficiency of up to 20.5%. Moreover, the power generated was up to 9.8% higher than that at different tilt angles.

Gain of Protection Afforded by the Methoxypropylamino Cyclohexenylidene Ethoxyethylcyanoacetate (MCE) UVA1 Filter on Pigmentary and Aging Signs: An Outdoor 4-Week Randomized, Intra-Individual Comparative Study in 52 Brazilian Women.

Conventional sunscreens shield the skin from ultraviolet (UV) rays up to 370 nm leaving wavelengths between 370 and 400 nm unfiltered despite their potentially harmful biological and clinical effects. The beneficial effects of methoxypropylamino cyclohexenylidene ethoxyethylcyanoacetate (MCE) UVA1 filter were explored at 1% in a SPF50 sunscreen under outdoors summer conditions against pigmentation and aging signs compared against a reference SPF50 without the MCE filter. A prospective randomized comparative intra-individual study was conducted in 52 Brazilian women (phototype I-III). A hemiface application was performed for the SPF50 sunscreen with 1% MCE and SPF50 reference without MCE before 1-h outdoor sunlight exposure, twice daily for 4 weeks. Study endpoint included expert panel grading of pigmentation (3), vascular (1) signs as well as facial skin ageing and assessment of facial skin radiance and skin homogeneity by a naïve panel. Significant differences were reported for all facial signs comparing areas protected with SPF50/MCE and SPF50, respectively: upper lip wrinkles, crow's feet wrinkles, upper lip texture, upper lip pigmentation, vascular abnormalities (all p < 0.0001), texture of the mouth contour (p = 0.001), ptosis of lower face (p = 0.003), lateral facial pigmentation (p = 0.005), and whole face pigmentation (p = 0.01). The evaluations performed by naïve panel showed a significant superiority of the SPF50/MCE product for skin homogeneity (p = 0.043). Overall, this study demonstrates a significant gain of protection with the SPF50 containing 1% MCE in reducing hyperpigmentation, redness and aging signs compared to the same SPF50 sunscreen without MCE, thus supporting the need for an enlarged UVA1 photoprotection.

Efficient Light to Heat Conversion in Sb2Se3 Nanorods and the Role of Macro-channel Imprinted Sb2Se3 Loaded Hybrid Membrane for Superior Desalination Performance.

This report validates Sb2Se3 nanorods (NRs) as a potential contender for solar thermal heat generation. The water droplet experiment shows Sb2Se3's light-to-heat conversion efficiency as ≈57.8% for red (671nm), 58% for green (532nm) lasers. Following this PVDF(M)/ Sb2Se3 NRs hybrid membranes for solar desalination reached ≈59°C in 15 minutes of illumination. The heat generation is dominated by an electron/hole-acoustic phonon scattering mechanism. Despite having superior visNIR absorption and heat localization in Sb2Se3 NRs, the hybrid membranes show an evaporation rate of 1.72 kg m-2h-1 only, even if mass loading is increased. The hydrophobic Sb2Se3 NRs layer restricts water diffusion to hot zones, reducing solar evaporation efficiency. A novel macrochannel imprinting strategy in hybrid membranes speeds up water transport to the hot zone. Consequently, optimized macrochannel membranes achieve ≈2.37kgm-2h-1 mass loss and 148% solar evaporation efficiency under a 1000Wm-2 mercury vapor lamp. Therefore, imprinting macro-channel can be a possible strategy, addressing the hydrophobic materials in desalination applications which can be expanded in other similar materials. Moreover, its outdoor sunlight application achieves impressive solar evaporation efficiency (≈108%). The steam generated effectively removes heavy metals, meeting World Health Organization (WHO) potable water standards.

Multi-Objective Optimization of Outdoor Thermal Comfort and Sunlight Hours in Elderly Residential Areas: A Case Study of Beijing, China

To optimize the outdoor thermal comfort and sunlight hours of elderly residential areas in cold regions of China, we collected data on streets and building forms from 121 elderly residential sites in Beijing. Utilizing parametric modeling tools to generate ideal residential models, a multi-objective optimization algorithm was applied to identify 144 Pareto solutions. The optimal solutions were analyzed using K-means clustering and Pearson correlation analysis to examine how block form affects outdoor environmental performance. The universal thermal climate index (UTCI) in summer showed significant positive correlations (r &gt; 0.72) with the distance between buildings (DB), building density (BD), shape coefficient (SC), and coefficient of variation for building height (CVH), and significant negative correlations (r &lt; −0.82) with average building height (AH), floor area ratio (FAR), volume area ratio (VAR), mean building area (MA), average building volume (AV), and open space ratio (OSR). Winter UTCI was significantly positively correlated with AH, FAR, VAR, MA, and AV (r &gt; 0.83) and significantly negatively correlated with DB, porosity (PO), SC, and CVH (r &lt; −0.88). Sunlight hours were significantly positively correlated with DB, PO, OSR, and CVH (r &gt; 0.84) and significantly negatively correlated with AH, BD, FAR, SC, VAR, MA, and AV (r &gt; 0.88). Courtyard and point-building configurations performed the best across all optimization objectives. (The value of r, Pearson’s correlation coefficient, ranges from −1 to +1. r = +1: Perfect positive correlation, r = −1: Perfect negative correlation, r = 0: No linear correlation).

Modulating intramolecular charge transfer via π-d conjugative effect in coordination polymers toward photo-thermo-electric conversion

The prospect of harnessing sunlight to generate cost-effective heat and electricity presents a captivating opportunity to address water scarcity and electricity shortages. Photothermal materials with a broad absorption spectrum are indispensable for effectively harnessing solar energy and converting it into heat/electricity. Herein, we developed an intramolecular charge transfer strategy via conjugated effect to regulate solar absorption and photothermal conversion ability of M-DABDT (M = Fe/Co/Ni/Cu/Zn, DABDT = 2,5-diaminobenzene-1,4-dithiol), overcoming a common limitation of narrow absorption and low photothermal efficiency in traditional metal-organic assemblies. The density functional theory calculations reveal that altering transition metal ions induces the structural torsion of organic linkers, resulting in a significant change in dihedral angle from 89.96° to 2.57°. The structural change significantly facilitates the charge transfer and electron relaxation, ultimately promoting the conversion of light to heat. Under one sun irradiation, the maximum temperature of Fe-DABDT can reach approximately 92.5 ℃. More significantly, the integration of M-DABDT CPs and thermoelectric devices under normal solar irradiation results in an extraordinary open circuit voltage (238 mV) and maximum power density (364.5 μW m−2), processing a peak output voltage density of 76.9 V m−2 at 11:00 a.m. in the presence of outdoor sunlight. This strategy presents an avenue for developing metal-organic solar absorbers for photo-thermo-electric conversion systems.

Towards water-resistant perovskite solar cells: Electron-beam deposited SiO2 layers for highly stable perovskite solar cells

Metal halide perovskite solar cells (PSCs) incorporating organic–inorganic compounds exhibit promising potential for future photovoltaic devices. One of the main obstacles to commercializing perovskite photovoltaic technology is oxygen and water-induced degradation in ambient conditions. Herein, we demonstrate a general approach to protect PSCs from water-induced degradation using electron-beam evaporated silicon dioxide (SiO2) barrier coating. A number of small (0.25 cm2) and large-area (2.0 cm2) PSCs have been fabricated to obtain statistically significant data. An optimal 1-μm thick SiO2 layer coated over RbCsMAFAPb(IBr)3-PSCs provided remarkable protection even after fully immersing the devices in a water-filled container. After immersing the PSC in water for 1 min, the device efficiency showed only a small reduction in efficiency from 14.3 % to 12.0 %, highlighting the excellent water protection offered by the barrier layer. We show that SiO2 barrier layers can improve the overall stability of the cells. Perovskite devices coated with 1 µm-SiO2 protective layers maintained more than 85 % of their initial power conversion efficiency (PCE) values after 2000 h in ambient storage. The devices coated with the optimum SiO2 layer thickness of 1 µm also showed excellent stability during outdoor sunlight testing for 2000 h, maintaining ∼ 80 % of their initial efficiency values.

One-Step Electrochemically Prepared Bionic Hierarchical Nickel Black@Graphene Composite Membrane for Desalination by Solar-Thermal Energy Conversion.

Ingenious microstructure construction and appropriate composition selection are effective strategies for achieving enhanced performance of photothermal materials. Herein, a broccoli-like hierarchical nickel black@graphene (Ni@Gr) membrane for solar-driven desalination was prepared by a one-step electrochemical method, which was carried out simultaneously with the electrochemical exfoliation of graphene and the co-deposition of Ni@Gr material. The bionic hierarchical structure and the chemical composition of the Ni@Gr membrane increased the sunlight absorption (90.36%) by the light-trapping effect and the introduction of graphene. The Ni@Gr membrane achieved high evaporation rates of 2.05 and 1.16 kg m-2 h-1 under simulated (1 sun) and outdoor sunlight conditions, respectively. The superhydrophilicity and the hierarchical structure of the Ni@Gr membrane jointly reduced the evaporation enthalpy (1343.6 kJ/kg), which was beneficial to break the theoretical limit of the evaporation rate (1.47 kg m-2 h-1). This work encourages the application of bionic metal-carbon composite photothermal materials in solar water evaporation.

3D printed cellulose nanofiber/silica nanoparticle scaffolds for daytime radiative cooling

The high degree of modularity and miniaturization of nanoelectronic devices results in a significant increase in heat flux per unit area of electronic components. This can cause a rise in temperature, especially when used outdoors under direct sunlight conditions, which can negatively impact their operational stability and service life. Traditional radiators have limited effectiveness in outdoor sunlight conditions. Additionally, conventional heat sinks are often too large and heavy for miniature electronic devices. Therefore, finding an effective solution to cool electronics under sunlight conditions remains a challenge. Herein, we present an innovative solution to fabricate 3D-printed coolers for electronic devices based on the methyltrimethoxysilane/silica/cellulose nanofibers (MSC) ink. 3D printing technology enables the fabrication of radiative coolers with complex structures and efficient cooling performance as needed. The combination of CNFs and SiO₂ nanoparticles, coupled with the porous nature of the structure, enables the 3D-printed MSC scaffold to exhibit excellent solar reflectance and high mid-infrared (MIR) emissivity, thereby facilitating superior radiative cooling capabilities. During the daytime, it can efficiently reduce the temperature of electronic devices by 6.16 °C, thereby improving their operational efficiency and service life. Furthermore, the 3D-printed MSC scaffold exhibits superior mechanical properties due to the robust 3D frame structure formed by the ink components, which provides stability for the electronic device during operation. This study presents an innovative approach to developing electronic device coolers with excellent cooling performance, which is significant in promoting the reliability and stability of electronic devices.

Bisphenol-A Leaching from Polycarbonate 5-Gallon Water Bottles in the UAE: A Comprehensive Study.

Bisphenol A (BPA) is widely used around the world in the production of Polycarbonate (PC) plastics. Notably, the ubiquitous 5-gallon water bottles in the UAE are primarily made of PC plastic, making them a significant concern as bottled water is the region's main supply of drinking water. These bottles undergo temperature variations during storage and transportation, potentially leading to harmful BPA (Bisphenol A) leaching. This study analyzed 40 PC 5-gallon water bottles from two local brands A and B, with 20 bottles per brand, under two conditions: room temperature and outdoor sunlight exposure for a month. BPA levels were assessed at 0, 15, and 30 days, following ethical approval. Liquid-liquid extraction and ELISA assays were conducted, with comprehensive kit validation. The results revealed a significant increase in BPA concentration over time, particularly in bottles exposed to elevated temperatures (Day 30 outdoor-stored samples exhibited the highest concentration at 9.05 ± 2.30 μg/L). Brand B consistently exhibited higher BPA concentrations across different samples and environments. This study emphasizes the link between BPA content and storage time, highlighting the need for preventive measures to reduce BPA exposure. Individuals should be aware of potential health risks associated with prolonged storage in plastic containers and consider safer alternatives.

Sunlight optimization in residential area design: Introducing sOSA - A comprehensive indicator for swift assessment of outdoor sunshine exposure

The increasing density and height of residential buildings have heightened the concerns regarding inadequate sunshine exposure in outdoor areas. With multi-objective optimization experiments, existing evaluation measures, such as Sunshine Times (ST), are not able to sufficiently capture the spatial features required to find the best design for outdoor sunlight conditions quickly. Spatial Outdoor Sunshine Autonomy (sOSA) is proposed in this paper as a comprehensive indicator for the rapid assessment of cumulative sunlight exposure in various outdoor scenarios. The definition of the indicator is first presented through formula derivation. Subsequently, the rapid simulation method of the sOSA indicator in Rhino is demonstrated. Utilizing the Maigao Bridge Block in Nanjing as a prototype, the application of this indicator in multi-objective optimization experiments for new residential area planning and design is showcased. Finally, the results are evaluated, and the suggestion is made to combine sOSA with ST maps and wind speed cloud maps for enhanced practical guidance.

An Efficient Indoor Nursery Controlled by IOT and Monitored by Android App.

Gardening is one of the greatest hobbies or mind relaxing activities for all age groups, which kindles them to make nursery management system. Nowadays also most of the nursery owners using a manual system to water and monitor their plants. There are many difficulties or challenges for nursery owners to take care of the plants growth, so that they need to check the moisture of the soil, monitor the air humidity and temperature, and others parameters. This paper offers a solution to combine the Internet of Things (IoT) system and Android apps to monitor the plant's growth with a real-time data monitoring and also provides the system control. In this paper, the sensors are used to sense the moisture of soil, check the air humidity and temperature, discover the light intensity and measure the soil temperature. This system allows nursery owners to monitor and control the irrigation system where they can water their plants using mobile application. The sensor checks the condition of the plant and updates the data in every one hour. Other than that, Indoor nursery often faces the issue of inadequate sunlight. Natural light coming through windows may not be as strong as outdoor sunlight, which is essential for photosynthesis. Therefore, this system offers a solution that allows nursery owners to control a specific light-emitting diode (LED) or UV LED to simulate sunlight. This ensures that plants receive the necessary light for photosynthesis and grow healthy. Growth of Plants contribute towards air purification providing fresher air to breathe.

Dual Channel H2O2 Photosynthesis in Pure Water over S-Scheme Heterojunction Cs3PMo12/CC Boosted by Proton and Electron Reservoirs.

Dual channel photo-driven H2O2 production in pure water on small-scale on-site setups is a promising strategy to provide low-concentrated H2O2 whenever needed. This process suffers, however, strongly from the fast recombination of photo-generated charge carriers and the sluggish oxidation process. Here, insoluble Keggin-type cesium phosphomolybdate Cs3PMo12O40 (abbreviated to Cs3PMo12) is introduced to carbonized cellulose (CC) to construct S-scheme heterojunction Cs3PMo12/CC. Dual channel H2O2 photosynthesis from both H2O oxidation and O2 reduction in pure water has been thus achieved with the production rate of 20.1mmolL-1gcat. -1h-1, apparent quantum yield (AQY) of 2.1% and solar-to-chemical conversion (SCC) efficiency of 0.050%. H2O2 accumulative concentration reaches 4.9mmol L-1. This high photocatalytic activity is guaranteed by unique features of Cs3PMo12/CC, namely, S-scheme heterojunction, electron reservoir, and proton reservoir. The former two enhance the separation of photo-generated charge carriers, while the latter speeds up the torpid oxidation process. In situ experiments reveal that H2O2 is formed via successive single-electron transfer in both channels. In real practice, exposing the reaction system under natural sunlight outdoors successfully results in 0.24mmol L-1 H2O2. This work provides a key practical strategy for designing photocatalysts in modulating redox half-reactions in photosynthesis.

Effects of climatic conditions of Al Seeb in Oman on the performance of solar photovoltaic panels

Human activities and climatic elements, including temperature, humidity, and wind speed, have an impact on natural dust deposition. Therefore, this study aims to investigate the effects of wind speed, relative humidity, and ambient temperature on the performance of soiled photovoltaic panels in Al Seeb, Oman. The study was conducted by exposing the solar PV panels to outdoor sunlight for a duration of two months. Parameters such as solar radiation, voltage, current, solar panel temperature, wind speed, relative humidity, and ambient temperature were collected in a short time interval. It was observed that the dust densities of 20.7 g/m2, 27 g/m2, and 41.3 g/m2 resulted in electrical power reductions of 18 %, 33 %, and 40 % for the panels uncleaned for one week, two weeks, and three weeks, respectively. The effect of daily dust resulted in an energy reduction of 14 %. Moreover, dust deposition decreases when the wind speed increases, resulting in a higher power output and vice versa. The higher the humidity, the stronger the dust's adhesion to the surface, resulting in more deposition and reduced power output. The maximum power output of 82.3 W was achieved at the wind speed of 10 m/s, 34.9 % relative humidity, and ambient temperature of 38.5 °C.

Effect of Rebar Harsh Storage Conditions on the Flexural Behavior of Glass FRP Concrete

Nowadays, fiber-reinforced polymer (FRP) has become a widely accepted alternative reinforcement to steel bars in concrete members due to its many sustainability traits, as represented by its high strength-to-weight ratio, corrosion resistance, non-conductive properties, and electromagnet neutrality. However, FRP bar exposure for an extended period of time to harsh environmental conditions and chemicals can have an adverse effect on their mechanical properties. In this investigation, glass FRP bars were exposed to indoor controlled temperature, outdoor direct sunlight, outdoor shade, seawater, and alkaline solution for six months prior to using them as reinforcement in concrete flexural members. This research involves the fabrication and testing of five pairs of 3 m-long concrete beams with 200 mm by 300 mm cross-sections embedded in the tension zone with the exposed GFRP bars. The 10 beams were instrumented with strain gauges and tested following a four-point loading scheme using a hydraulic jack attached to a rigid steel frame. Crack width records from the tests showed the inferior serviceability of the beams that contained rebars stored in an outdoor environment relative to the control beams. GFRP bar exposure to an alkaline solution or outdoor direct sunlight slightly affected the cracking and ultimate moment capacities, reducing them by 5% and 3% in terms of the same parameters as the controlled indoor exposure, respectively. The influence of GFRP bar exposure to open-air shade or sunlight decreased the pre-cracking stiffness by 25% and flexural ductility by 10–20% when compared with the control specimens. The predicted ultimate flexural strength using the ACI 440 provisions gave comparable results to the experimentally obtained values. A simple mathematical equation that envelops the moment–deflection relationship for GFRP over-reinforced concrete beams and only requires information about initial cracking and ultimate flexural conditions is proposed.

Top–down versus bottom–up oxidation of a neonicotinoid pesticide by OH radicals

Emerging contaminants (EC) distributed on surfaces in the environment can be oxidized by gas phase species (top-down) or by oxidants generated by the underlying substrate (bottom-up). One class of EC is the neonicotinoid (NN) pesticides that are widely distributed in air, water, and on plant and soil surfaces as well as on airborne dust and building materials. This study investigates the OH oxidation of the systemic NN pesticide acetamiprid (ACM) at room temperature. ACM on particles and as thin films on solid substrates were oxidized by OH radicals either from the gas phase or from an underlying TiO2 or NaNO2 substrate, and for comparison, in the aqueous phase. The site of OH attack is both the secondary >CH2 group as well as the primary -CH3 group attached to the tertiary amine nitrogen, with the latter dominating. In the case of top-down oxidation of ACM by gas phase OH radicals, addition to the -CN group also occurs. Major products are carbonyls and alcohols, but in the presence of sufficient water, their hydrolyzed products dominate. Kinetics measurements show ACM is more reactive toward gas phase OH radicals than other NN nitroguanidines, with an atmospheric lifetime of a few days. Bottom-up oxidation of ACM on TiO2 exposed to sunlight outdoors (temperatures were above 30 °C) was also shown to occur and is likely to be competitive with top-down oxidation. These findings highlight the different potential oxidation processes for EC and provide key data for assessing their environmental fates and toxicologies.

Spatially thermal confinement nanoreactors for efficient photocatalytic microinterface reactions and application prospect evaluation under real weather and actual water matrices

Photothermal photocatalysis has been a breakthrough in the photocatalysis field, yet the wasted radicals, insufficient contact of pollutant with catalyst, and low utilization efficiency of heat energy are the major barriers for practical application. In this work, a novel full-spectrum adsorption catalyst (MoS2-MoO3/C3N4) with interlayer confinement space (OMS-CNS) was fabricated as “spatially thermal confinement nanoreactor”, which can enrichment pollutants, free radicals and photothermal effect to improve the degradation efficiency of ampicillin (AMP) by 2.06 times. The synergistic of confinement effects and photothermal effects concentrated heat in the interlayer nanoreactor and simultaneously promoted the generation of •O2− and 1O2, further contributed to a more harmless degradation pathway for AMP compared with conventional photothermal photocatalytic systems. Furthermore, the enlarged interlayer spacing and high interlayer adsorption energy (Eads) enabled AMP to enter the nanoreactor for quick reaction with newly generated active radicals under locally high temperature, avoiding heat loss and the diffusion limitation of free radicals. Furthermore, the excellent degradation efficiencies of AMP were also maintained even in the actual wastewater matrices or at outdoor sunlight irradiation due to the construction of confinement space with high temperature environment and enriched ROS. The combination of the confinement catalysis and photothermal effects provides promising insight into efficient photocatalysis performance.

Wavelength-dependent direct and indirect photochemical transformations of organic pollutants

Sunlight-induced photochemical transformations greatly affect the persistence of organic pollutants in natural environment. Whereas sunlight intensity is well-known to affect pollutant phototransformation rates, the reliance of pollutant phototransformation kinetics on sunlight spectrum remains poorly understood, which may greatly vary under different spatial-temporal, water matrix, and climatic conditions. Here, we systematically assessed the wavelength-dependent direct and indirect phototransformations of 12 organic pollutants. Their phototransformation rates dramatically decreased with light wavelength increasing from 375 to 632 nm, with direct photolysis displaying higher wavelength-dependence than indirect photolysis. Remarkably, UV light dominated both direct (90.4–99.5 %) and indirect (64.6–98.7 %) photochemical transformations of all investigated organic pollutants, despite its minor portion in sunlight spectrum (e.g., 6.5 % on March 20 at the equator). Based on wavelength-dependent rate constant spectrum, the predicted phototransformation rate of chloramphenicol (4.5 ± 0.7 × 10−4 s−1) agreed well with the observed rate under outdoor sunlight irradiation (4.3 ± 0.0 × 10−4 s−1), and there is no significant difference between the predicted rate and the observed rate (p-value = 0.132). Moreover, rate constant and quantum yield coefficient (QYC) spectrum could be applied for facilely investigate the influence of spectral changes on the phototransformation of pollutants under varying spatial-temporal (e.g., season, latitude) and climatic conditions (e.g., cloud cover). Our study highlights the wavelength-dependence of both direct and indirect phototransformation of pollutants, and the UV part of natural sunlight plays a decisive role in the phototransformation of pollutants.

Gallium oxide cantilevered thin film-based solar-blind photodetector and its arc detection applications

The performance of gallium oxide (Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;) thin film detector based on metal-semiconductor-metal (MSM) is highly dependent on the uniformity of the Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; thin film, and the manufacturing process is quite sophisticated, which poses a challenge for the scale-up and mass production of thin film photodetectors. In this work, an MSM Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; thin film solar-blind photodetector with five-finger interdigital electrodes is fabricated by physically depositing Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; thin film on the surface of a mass-produced cantilevered thin film chip. Through the microelectromechanical system (MEMS) process, the cantilever electrode structure is prepared, which protects the internal circuit and the integrity of the thin film. The Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; thin film treated by argon plasma at a low temperature is amorphous, but the photodetector still possesses considerable ultraviolet detection performance. At a bias voltage of 18 V, it approaches the detection performance of crystalline Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; thin film, with a detectivity of 7.9×10&lt;sup&gt;10&lt;/sup&gt; Jones, an external quantum efficiency of 1779%, rise time and decay time of 1.22 s and 0.24 s, respectively. Moreover, a system of arc detection is built in outdoor environments. Without any optical focusing system, this photodetector achieves sensitive detection of pulsed arc in an outdoor sunlight environments. For pulsed arcs with an output voltage of 100 kV, the photodetector is capable of sensitive detection at a distance of 25 cm. Besides, the maximum detection distance of 155 cm indicates that the photodetector will have a favorable potential application value in the field of solar-blind detection. This work develops a sensitive functional thin film deposition technology based on the cantilever electrode structure fabricated by the MEMS process, which avoids the influence of the large-area uniformity of the functional thin film on the etching circuit. It provides a new technical approach and process route for preparing MSM photodetectors.

Competition between Dissolved Organic Matter and Freshwater Plankton Control Methylmercury Isotope Fractionation during Uptake and Photochemical Demethylation.

Isotope fractionation related to photochemical reactions and planktonic uptake at the base of the food web is a major uncertainty in the biological application of mercury (Hg) stable isotopes. In freshwater systems, it is unclear how competitive interactions among methylmercury (MeHg), dissolved organic matter (DOM), and phytoplankton govern the magnitude of mass-dependent and mass-independent fractionation. This study investigated how DOM alters rates of planktonic MeHg uptake and photodegradation and corresponding Hg isotope fractionation in the presence of freshwater phytoplankton species, Raphidocelis subcapitata. Outdoor sunlight exposure experiments utilizing R. subcapitata were performed in the presence of different DOM samples using environmentally relevant ratios of MeHg-DOM thiol groups. The extent of Δ199Hg in phytoplankton incubations (2.99‰ St. Louis River HPOA, 1.88‰ Lake Erie HPOA) was lower compared to paired abiotic control experiments (4.29 and 2.86‰, respectively) after ∼30 h of irradiation, resulting from cell shading or other limiting factors reducing the extent of photodemethylation. Although the Δ199Hg/Δ201Hg ratio was uniform across experiments (∼1.4), Δ199Hg/δ202Hg slopes varied dramatically (from -0.96 to 15.4) across incubations with R. subcapitata and DOM. In addition, no evidence of Hg isotope fractionation was observed within R. subcapitata cells. This study provides a refined examination of Hg isotope fractionation markers for key processes occurring in the lower food web prior to bioaccumulation, critical for accurately accounting for the photochemical processing of Hg isotopes across a wide spectrum of freshwater systems.

Time spent in outdoor light is associated with the risk of dementia: a prospective cohort study of 362094 participants

AbstractBackgroundFew epidemiological studies in the adult population related these outcomes to daytime sunlight exposure.MethodData were from a prospective cohort of 362094 UK Biobank participants. Questionnaire survey was conducted to investigate how many hours the participants spent outdoors on typical summer and winter days. Restricted cubic spline (RCS) was performed to explore the potential nonlinear relationship between sunlight exposure and the risk of dementia.ResultMore specifically, we prefer to describe this nonlinear relationship with J shape, the lowest risk at three change points (1.5 hours/day on average, 2 hours/day in summer, and 1 hour/day in winter). Since for sunlight exposure, a marked increase in risk was observed at low exposure, but a relatively slow elevation in risk at higher exposure.ConclusionThere is a J‐shaped correlation between outdoor sunlight exposure time and dementia risk.