Shading Effect Research Articles

Shading Performance of Plant and Perforated Metal in The Thermal, Light, and Building-occupant Perception

Visual and thermal comfort are essential aspects influencing the activity of building occupant. For buildings with glass facades, the integration of shading devices becomes essential to enhance user comfort. This study aims to compare the effects of artificial (perforated metal) and biotic shading (Vernonia elliptica plant) on the thermal and visual parameters as well as perception of respondents regarding both devices. The study was carried out using a 1m x 1m x 1m box model. Perforated metal had a diameter of 3 cm and a spacing of 2 cm with a 29% openness factor, while the Vernonia elliptica had 2 levels of density, namely LAI 1 and LAI 2. The results showed that there was no significant difference in the average air temperature and RH produced by shading of vegetation LAI 1, LAI 2, and perforated metal. However, the use of vegetation reduced the illuminance significantly compared to the other device. The average DF of perforated metal ranged from 15.4 to 25%, while a range of 1.9-4.1% was obtained for LAI 1 and LAI 2. These results were inconsistent with building occupant’s perception that the vegetation had a better effect on the thermal aspect than the visual aspect.

Disentangling shade effects for cacao pest and disease regulation in the Peruvian Amazonia

Disentangling shade effects for cacao pest and disease regulation in the Peruvian Amazonia

A numerical study of ocean surface‐layer response to atmospheric shallow convection: Impact of cloud shading, rain, and cold pools

AbstractThe response of the oceanic surface layer to atmospheric shallow convection is explored using realistic atmospheric large eddy simulations coupled with an oceanic 1D model with high vertical resolution. The effects of cloud shading, rain, and enhanced heat loss due to gust fronts on the edge of cold pools and their interactions are investigated in a case study of the Cooperative Indian Ocean Experiment on Intraseasonal Variability/Dynamics of the Madden–Julian Oscillation experiment in the tropical Indian Ocean, during a suppressed phase of the Madden–Julian Oscillation. Conditions of low surface wind and strong solar heating result in diurnal warming of the oceanic surface of 2 °C over a depth of 1 m. Analysis of specific periods covering the diurnal cycle shows the contrasting effects of cloud shading, rain, and turbulent heat fluxes under the cold pools on the sea temperature at the surface and below. On the one hand, decreasing the solar radiation (cloud shading) results in slight cooling extended horizontally and penetrating down to 1–2 m depth, depending on the time of the day. On the other hand, turbulent heat fluxes enhanced up to 300 Wm by gusts and freshwater lenses due to rain act together and more locally. They isolate and strongly cool a thin inner layer at the surface, which eventually destabilizes the surface layer and propagates the cooling downward. The exact relative part and efficiency of these processes depend on the time evolution of the thermal stratification and vertical turbulent mixing in the oceanic upper layer. Surface cooling of up to 0.5 °C may occur in a few tens of minutes and last for several hours, significantly mitigating the effects of diurnal warming over large extents.

Interaction of Fe2O3 nanoparticles with marine microalga Chlorella sorokiniana: Analysis of growth, morphological changes and biochemical composition

The wide utilization of iron-based nanoparticles (NPs) based on their preferential properties has led to the discharge and accumulation of these materials into the aquatic environment. In this regard, a comparative study of different concentrations of α-Fe2O3 NPs and their micro form was conducted using microalga Chlorella sorokiniana up to the stationary growth phase. This study revealed that high concentrations of NPs (100 and 200 mg L−1) imposed a stressful condition on algal cells documented by a reduction in microalga growth, including cell number and specific growth rate. The physical contact between the algal cells and NPs resulted in a shading effect as well as morphological changes validated by scanning electron microscope results. The biochemical composition of C. sorokiniana exposed to high levels of Fe2O3 NPs was also evaluated. The increase in total carbohydrate content of algal cells along with a significant reduction in unsaturated fatty acids was found. Moreover, Fe2O3 NPs exposure induced oxidative stress evidenced by an increase in lipid peroxidation. To cope with oxidative stress, superoxide dismutase activity and antioxidant potential of microalga as defensive mechanisms increased in the culture with high concentrations of NPs. Besides, due to the interactions, microalga tended to form a protective layer from further cell-NP interactions through the secretion of extracellular polymeric substances. Nonetheless, the nano form of Fe2O3 was more toxic than its micro form due to its small size. Overall, this trial may provide additional insight into the toxicological mechanism and safety assessments of Fe2O3 NPs in the aquatic environment.

A Machine Learning Approach to Estimating Solar Radiation Shading Rates in Mountainous Areas

Quantification of shading effects from complex terrain on solar radiation is essential to obtain precise data on incident solar radiation in mountainous areas. In this study, a machine learning (ML) approach is proposed to rapidly estimate the shading effects of complex terrain on solar radiation. Based on two different ML algorithms, namely, Ordinary Least Squares (OLS) and Gradient Boosting Decision Tree (GBDT), this approach uses terrain-related factors as input variables to model and analyze direct and diffuse solar radiation shading rates. In a case study of western Sichuan, the annual direct and diffuse radiation shading rates were most correlated with the average terrain shading angle within the solar azimuth range, with Pearson correlation coefficients of 0.901 and 0.97. The GBDT-based models achieved higher accuracy in predicting direct and diffuse radiation shading rates, with R2 values of 0.982 and 0.989, respectively, surpassing the OLS-based models by 0.081 and 0.023. In comparisons between ML models and classic curve-fitting models, the GBDT-based models consistently performed better in predicting both the direct radiation shading rate and the diffuse radiation shading rate, with a standard deviation of residuals of 0.330% and 0.336%. The OLS-based models also showed better performance compared to the curve-fitting models.

The Hot Spot phenomena in Shadowed ENR System

Model to represent the behaviour of photovoltaic (PV) solar cells in reverse bias is reviewed, concluding with a proposal of new model. This model comes from the study of avalanche mechanisms in PV solar cells, it can be adapted to PV cells witch reverse characteristic is dominated by avalanche mechanisms, and also dominated by shunt resistance. A simulation of shading effects in arrays with parallel series configuration has been done; an analysis has been made of the power dissipation with the influence of the number of shaded cells and the effect of shadowing degree.

Modified Odd–Even–Prime pattern for effective dispersion of shade over the PV array under partial shading conditions

Photovoltaic (PV) arrays are extensively used for power generation being the most abundant renewable energy sources available. Partial shading of the PV array leads to mismatch between the modules and decrease in output power. A new Modified Odd–Even–Prime (MOEP) method of module arrangement for total cross tied (TCT) connection is presented in this paper to mitigate the effects of partial shading. The proposed MOEP method is a physical relocation method where the modules of PV array are relocated without altering the electrical connections. MOEP method of module rearrangement is based on row positions of the PV array. In this method, the row positions of PV modules in the first column are filled with odd, even and prime numbers in ascending order. The row positions of further columns are formed based on MOEP method. The proposed MOEP method is implemented on 9 × 9 and 8 × 8 PV arrays under various shading patterns. Further, the results are compared with TCT, Odd Even (OE) and Odd–Even–Prime (OEP) patterns. MATLAB/Simulink is used to validate the results. An experimental setup of 9 × 9 and 8 × 8 PV array is developed and tested in real time environment to validate the effectiveness of MOEP method over TCT, OE and OEP methods. The performance of proposed MOEP method is evaluated in terms of GMPP, mismatch power loss (MPL), Fill Factor (FF), Efficiency (η) and Shade Dispersion Ratio (SDR). A detailed study on energy savings from the proposed MOEP method is made on hourly, daily and yearly basis. From the experimental results obtained, it is observed that MOEP method generates a significant improvement in GMPP, efficiency and reduces the mismatch loss compared to TCT, OE and OEP methods.

Effects of Differential Shading on Summer Tea Quality and Tea Garden Microenvironment.

Shading is an effective agronomic technique to protect tea plants from intense sunlight. However, there are currently very few studies on more effective shading methods to improve the quality of summer tea. In this study, 'Longjing43' plants were grown under four different shading treatments for 14 days, with no shading as the control. Among the four shading treatments, double-layer-net shadings had the most positive impact on the tea quality, resulting in higher levels of amino acids but lower levels of tea polyphenols. Additionally, double-layer-net shadings provided more suitable microenvironments for tea plants. The tea leaves in T4 (double nets 50 cm above the plant canopy) contained 16.13 mg∙g-1 of umami and sweet amino acids, which was significantly higher than in other treatments. T4 had the lowest air temperature and the most suitable and stable soil water content. Interestingly, the ratio of red light to far-red light in T4 was only 1.65, much lower than other treatments, which warrants further study. In conclusion, the microenvironment induced by shading can greatly affect the tea quality, and double-layer-net shading is better for improving the quality of summer tea.

Shading effects in agrivoltaic systems can make the difference in boosting food security in climate change

Photovoltaic (PV) systems play an important role in the sustainable energy transition, but their impact on food security is ambiguous due to the shift in land use from agriculture to energy production. Currently, agrivoltaic is emerging as an alternative sustainable energy source that optimises multifunctional land use by simultaneously supporting electricity generation and agricultural activities. While many studies have extolled the benefits of shade provided by agrivoltaic on crop water balance and evapotranspiration, plant ecological adaptation, such as Shade Avoidance Syndrome (SAS), and its implications for food security remain relatively unexplored. In this context, we have investigated the influence of a panel-generated shadow on chicory crop production in terms of plant biomass yield and its quality for human health under different water irrigation regimes. For each chicory plant, fresh weight and leaf dimensions were measured to estimate edible biomass, while leaf water content, chlorophylls a and b, carotenoids, metabolite profile and antioxidant capacity were evaluated to assess food quality. Our results show that the shading system has a remarkable capacity to increase edible chicory biomass production compared to full sunlight conditions of 69% and 23%, respectively for high water supply and low water supply, and greater capacity to promote pollination ecosystem services. The shade, provided by a well-designed agrivoltaic system, improves SAS and directly increase yield without altering food quality. Thus, agrivoltaic systems can combine renewable energy strategies with food security, while enhancing ecosystem services for human well-being.

Mathematical Modelling and Statistical Analysis of Improved Grey Wolf Optimized Maximum Tracking for Solar Photovoltaic Energy System Under Non Linear Operational Conditions

IAs the utilization of solar photovoltaic (PV) energy systems continues to expand, the efficient extraction of energy under non-linear operational conditions becomes paramount. This research focuses on the development and enhancement of a Maximum Power Point Tracking (MPPT) algorithm, specifically tailored for solar PV systems, through the integration of Improved Grey Wolf Optimization (IGWO) techniques. The study utilizes mathematical modeling and statistical analysis to evaluate the performance of the proposed IGWO-based MPPT algorithm. This research, we first establish a comprehensive mathematical model of a solar PV energy system that accurately represents its non-linear operational characteristics, taking into account factors such as temperature variations, shading effects, and changing environmental conditions. Subsequently, we introduce the Improved Grey Wolf Optimization algorithm to optimize the MPPT process, aiming to enhance energy extraction efficiency by dynamically adapting to varying conditions. The statistical analysis includes the comparison of the IGWO-based MPPT algorithm with conventional MPPT methods, such as Perturb and Observe (P&O) and Incremental Conductance (IncCond), under various non-linear operational scenarios. Key performance metrics, including energy conversion efficiency, response time, and tracking accuracy, are thoroughly evaluated to assess the algorithm's effectiveness in real-world conditions. The results of this study demonstrate the superior performance of the IGWO-based MPPT algorithm in enhancing the energy harvesting capabilities of solar PV systems under non-linear operational conditions. The proposed approach not only improves the overall energy conversion efficiency but also reduces the adverse effects of environmental variables on the system's performance. In conclusion, the integration of Improved Grey Wolf Optimization into the MPPT process represents a promising advancement in the field of solar photovoltaic energy systems. The mathematical modeling and statistical analysis conducted in this research provide valuable insights into the practical benefits of this approach, paving the way for more efficient and reliable solar energy utilization in the future.

A comprehensive study of how urban morphological parameters impact the solar potential, energy consumption and daylight autonomy in canyons and buildings

Over the past two decades, global greenhouse gas emissions have surged, leading to rising sea levels and climate change. Solar energy has emerged as an excellent solution to this problem. This study aims to assess daylight availability and energy consumption in urban canyons and blocks in a semi-arid climate while exploring the correlation between the heterogeneity of urban morphological parameters and key research variables. The study employed field measurements and simulations using Ladybug Tools and UMI. Data were collected from urban canyons and blocks in three areas, amounting to 1,366,982 m2. The findings indicate that areas with abundant greenery and H/W ratios exceeding 1.8 experience the most significant shading effects in urban canyons. Selecting suitable trees and placing them in strategic locations can enhance energy efficiency. Furthermore, broad urban canyons (H/W < 0.5) receive four times more solar radiation than narrow urban canyons (H/W > 1.8) with high tree density, peaking at 240 kWh/m2 during summer. In urban blocks, rooftops have the highest solar potential, with imbalances between building heights and interbuilding shading as factors that reduce solar capabilities. Tree coverage significantly affects the solar potential of facades, with some urban blocks receiving less than 5,000 kWh/m2 of solar radiation on the southern facades each month. Finally, this study examined the impact of heterogeneity within urban morphological parameters on the principal research variables. The results indicate that the heterogeneity observed in urban morphological parameters affects daylight availability and energy consumption within urban blocks.

Stress detection in vegetation based on remotely sensed light absorption coefficient

ABSTRACT Environmental stresses on plants are among the major limitations to crop productivity. Plants are naturally equipped with a set of acclimatory mechanisms enabling them to withstand stresses without irreversible damage. Here, we overhauled the approach to non-invasive gauging of the response of maize to combined drought and high-light stresses. This was done to leverage the advantages of a recently developed framework based on using the reflected signal absorption coefficient modality. We document the deployment of two responses, one based on non-photochemical quenching (NPQ) of the absorbed light energy and the second on the adjustment of leaf photosynthetically active radiation (PAR) interception. The NPQ-based response, implemented by the xanthophyll cycle and inferred from changes in the reflection of light in the blue-green region of the spectrum, engaged at the beginning of the stress but quickly reached a plateau. We demonstrate that altering leaf absorption in PAR is a fundamental plant response mechanism to diverse stresses. This response is quantified by the PAR absorption coefficient retrieved from the non-destructively measured reflectance. A profound decrease in the PAR absorption coefficient in the whole PAR region was shown to be a reliable measure of the degree of stress regardless of its cause. The effects of superficial shading and leaf position were readily detectable by the leaf PAR absorption coefficient. We consider this report a proof of concept for quantifying plant stress and monitoring the acclimation state via the absorption coefficient in the PAR region through non-destructive, remotely sensed techniques.

Sensitivity analysis of the shading effects from obstructions at different positions on solar photovoltaic panels

The solar radiation received by PV panels is often affected by neighboring shading objects, such as the surrounding terrain and adjacent buildings. Based on the dynamic spatial relationships among shading objects, the PV panel, and the sun, this research develops a method to quantify shading effects on solar radiation received by PV panels due to obstructions at different positions. By calculating the shading rates of direct and diffuse radiation, the sensitivities of PV panel's shading effects to various positions of 1080 shading blocks at sky dome are determined. It was found that the most sensitive areas of the PV panel's solar radiation shading rates were in the south, but their altitude angles varied greatly. With latitudes of 0°, 30°, and 60°, the maximum sensitivities of the direct and the diffuse radiation shading rates were found to be 1.21 % and 0.32 %, 1.69 % and 0.64 %, and 1.88 % and 1.05 %, respectively. The research offers a new approach to easily identify different sensitive shading areas of the direct and diffuse shading rates, which could provide theoretical supports for PV system planning, site selection, and layout optimization under diverse shading conditions.

Designing a photocatalytic and self-renewed g-C3N4 nanosheet/poly-Schiff base composite coating towards long-term biofouling resistance.

Inhibiting the adhesion and growth of marine microorganisms through photocatalysis is a potentially efficient and environmentally friendly antifouling strategy. However, the undesired "shading effect" caused by resin coatings and microbial deposition reduces the utilization of the catalysts and leads to a failure in the antifouling active substance on the coating surface. Here, we successfully developed a composite coating (DPC-x) combining g-C3N4 nanosheet (g-C-NS) photocatalysts with degradable green poly-Schiff base resins, which integrates the dual functions of enhanced dynamic self-renewal and photocatalytic antibacterial activities towards long-term anti-biofouling. The controllable and complete degradability of the poly-Schiff base polymer chains and the self-renewal mechanism of the DPC-x coating exposed the internal g-C-NS, which provided a constant stream of photocatalytic reactive interfaces for 100% utilization and release of the photocatalysts. g-C-NS were homogeneously dispersed in the degradable resin coating, significantly enhancing and adjusting the self-renewal rate of the poly-Schiff base resin coating in visible light. The degradation reaction rate of DPC-0.2 (20 wt% g-C-NS) was 40 times that of DPC, thus improving the capabilities of surface self-renewal and fouling-release. Due to the synergistic antifouling mechanism of the efficient antibacterial properties and the enhanced degradation/self-renewal, the antimicrobial rates of DPC and DPC-0.2 were 94.58% and 99.31% in the dark, and 98.2% and 99.87% in visible light. DPC-x has excellent all-weather antimicrobial efficacy and could offer a new perspective on eco-friendly marine antifouling strategies.

The role of trees in enhancing outdoor thermal comfort during warm season in a sub-humid climate. Case: Souk Ahras city

Enhancing the quality of life for people in urban areas necessitates focusing on outdoor thermal comfort OTC. This study examines the role and impact of urban vegetation, particularly trees, in improving the meteorological conditions that characterize the urban microclimate in order to enhance OTC, focusing on two public spaces in Souk Ahras city, characterised by in situ measurement campaigns and modelling during hot summer day. In situ campaigns were carried out to measure climatic data (air temperature, relative humidity and wind speed), and to collect data on vegetation (trees) and building geometry, which were used in numerical modelling to calculate the various thermal indices: SVF, Tmrt, PET and OUT_SET using the Rayman microclimatic model. The results show that the trees at each intervention site can reduce the average daily air temperature of 0.376?C to 1.04?C and an enhancement of thermal comfort in terms of average radiant temperature Tmrt of 2.08?C to 5.85?C and equivalent physiological temperature PET of 1.91?C to 3.84?C and standard equivalent temperature OUT_SET of 1.72?C to 2.86?C. in the knowledge that trees also help to reduce the Skye view factor, an essential geometric measure for assessing the thermal environment, which proves that the effect of shading and evapotranspiration provided by trees mainly contribute to enhancing outdoor thermal comfort during the warm season.

Effect of shade and spacing on growth performance of Bergenia ciliata: An important medicinal plant of North-Western Himalayas

Effect of shade and spacing on growth performance of Bergenia ciliata: An important medicinal plant of North-Western Himalayas

Metabólito secundário do extrato de folhas de cardamomo de Java em função de sombreamento e doses de nitrogênio

ABSTRACT Java cardamom is a species of herbal medicinal plant endemic to West Java, Indonesia, that has been used for a long time in traditional medicine. The effects of shading and nitrogen doses on the Gas Chromatography-Mass Spectrometry (GC-MS) profile, total phenolic and flavonoid contents, and antioxidant activity in the ethanol extract of Java cardamom leaves were investigated in this study. The experiment was conducted using a split-plot scheme with three replicates. The main plot constituted shading (without, 25, 50, and 75%), and the sub-plot comprised nitrogen doses (control, 0.9, and 1.36 g nitrogen fertilizer per polybag). GC-MS analysis found 27 compounds in the ethanol extract of Java cardamom leaves. The compounds 1.8-Cineole (36.87%) and 5-Hydroxy-3,7,4’-trimethoxyflavone (18.83%) had the highest concentrations in the combination of 25% shade with 0.9 g N fertilizer per polybag and 50% shade with 1.36 g N fertilizer per polybag. The highest total phenolic content (1.26 mg gallic acid equivalent g-1 dry weight), flavonoid content (3.42 mg quercetin equivalent g-1 dry weight), and ferric reducing antioxidant power (FRAP) antioxidant activity (5.80 μmol Trolox equivalent antioxidant capacity g-1 dry weight) were found with 75% shade. Metabolites 1-Methyl-4-isopropyl-cis-3-hydroxycyclohex-1-ene-6-one, 4-propoxy-catechol, cyclohexane, tert-pentyl-, cis-p-Menth-2,8-dienol, cis-carveol, and cis-p-mentha-1(7),8-dien-2-ol were responsible for antioxidant activity in the ethanol extract of Java cardamom leaves. Shade of 75% is recommended to produce optimal antioxidant activity and phenolic and flavonoid content from Java cardamom leaf extract.

Effect of Shade and Light Curing Mode on the Degree of Conversion of Silorane-Based and Methacrylate-Based Resin Composites

Effect of Shade and Light Curing Mode on the Degree of Conversion of Silorane-Based and Methacrylate-Based Resin Composites

Porphyrin metabolism and carbon fixation response of Skeletonema costatum at different growth phases to mixed emerging PFASs at environmental concentrations.

Per- and polyfluoroalkyl substances (PFASs), especially as emerging compounds, have been widely detected in coastal seawater. However, the awareness of the interaction between PFASs at environmental concentrations and marine diatoms is still limited. In this study, Skeletonema costatum was exposed to three co-existing PFASs, namely hexafluoropropylene oxide dimer acid (HFPO-DA), 6 : 2 chlorinated polyfluorinated ether sulfonate (Cl-PFAES), and perfluoroethylcyclohexane sulfonate (PFECHS) (15-300 ng L-1 in total), for 14 days. In the 300 ng L-1 test group, the significant down-regulation of chlorophyllide a in porphyrin metabolism, light-harvesting capacity and carbon fixation were the main inhibitory mechanisms of photosynthesis by emerging PFASs at the 14th day compared to the 8th day, which indicated that they may have a shading effect on S. costatum. Additionally, mixed PFASs could also activate nicotinamide adenine dinucleotide phosphate (NADPH) oxidase by up-regulating gene gp91 and down-regulating genes CaM4 and NDPK2 to generate excessive ROS. This resulted in a decrease in the algal biomass, which would further weaken the primary productivity of S. costatum. Our findings illustrated that mixed emerging PFASs at environmental concentrations may interfere with the carbon balance of marine diatoms.

Region-Aware Color Smudging.

Color smudge operations from digital painting software enable users to create natural shading effects in high-fidelity paintings by interactively mixing colors. To precisely control results in traditional painting software, users tend to organize flat-filled color regions in multiple layers and smudge them to generate different color gradients. However, the requirement to carefully deal with regions makes the smudging process time-consuming and laborious, especially for non-professional users. This motivates us to investigate how to infer user-desired smudging effects when users smudge over regions in a single layer. To investigate improving color smudge performance, we first conduct a formative study. Following the findings of this study, we design SmartSmudge, a novel smudge tool that offers users dynamical smudge brushes and real-time region selection for easily generating natural and efficient shading effects. We demonstrate the efficiency and effectiveness of the proposed tool via a user study and quantitative analysis.