Shading Effect Research Articles

Quantifying the Shading Effects of a Small-Scale Rooftop-Installed Linear Fresnel Reflector in Cyprus

Linear Fresnel reflectors are a versatile solar concentration technology, suitable for a wide range of industrial processes and thermal conditioning applications. Such collectors entail a certain footprint, generating shading on the surface where they are installed. This effect is rarely quantified but may play an indirect role on the surface below. When installed on a roof, the solar radiation heats the building less. In places where the annual heating demand is higher than the cooling demand, this constitutes an asset. However, this becomes a disadvantage when the cooling demand is higher annually than the heating demand. Essentially, the reduced solar radiation allows for the growth of plants that would not grow without the shade provided by the collector. The present paper is a quantitative analysis of such shading based on the linear Fresnel reflector of the Cyprus Institute. The work was conducted using the Tonatiuh++ ray-tracing software to determine the annual radiation blocking. A total of four years of actual meteorological measurements were applied directly to the ray-tracing model.

Effect of Shading and Foliar Spraying with Nutrient Solution on Vegetative Growth and Yield Traits of Sweet Orange Trees cv. Local.

Effect of Shading and Foliar Spraying with Nutrient Solution on Vegetative Growth and Yield Traits of Sweet Orange Trees cv. Local.

Elephant skin-inspired mycelium tiles for thermal regulation of buildings

Abstract Of all types of ecosystems, cities are the most polluting and this pollution affects more than 50% of the global population. One main cause for this pollution is related to the energy used to heat or cool down buildings. Currently, only 15% of households in Southeast Asia have an air conditioner, but this number is expected to rise, leading to an increase in demand in energy consumption, electricity and CO2 emissions which could further worsen global pollution and climate change. There is therefore an urgent need to find alternative solutions to cool buildings and regulate their temperatures. In this paper, inspiration is taken from elephants who live in very hot climates. Elephants can cool themselves thanks to the wrinkles on their skin that can limit heat gain, dissipate energy by evaporative cooling and store water. To emulate elephants’ cooling, tiles with elephant skin-inspired surface texture are designed. Computational simulations are performed to evaluate the effect of local shading due to the texture. Experimental tiles are produced using a biodegradable and natural material grown by a fungus, Pleurotus Ostreatus. These tiles are mycelium-bound composites (MBCs) where the fungus grew on bamboo microfibers, developing an interconnected web of cells called the mycelium that binds the microfibers together. The thermal properties of the tiles were measured for heating and cooling on the textured and flat side. The results show the tiles have anisotropic properties with a significant improvement by 25% in the cooling of the textured side over the flat side. In simulated rain conditions, the cooling is further improved by 42% as compared to dry conditions. The elephant-mycelium tiles are therefore promising for thermal regulation of building in Southeast Asia environments.

Studying the Shading Effect of PV System on Energy Performances in Restricted Spaces

Studying the Shading Effect of PV System on Energy Performances in Restricted Spaces

Fruit quality, antioxidant, and mineral attributes of pomegranate cv. Ghojagh, influenced by shading and spray applications of potassium sulfate and sodium silicate

Pomegranate (Punica granatum L.) fruit quality depends on many traits including visual, biochemical and mineral characteristics. One of the negative traits is aril whitening (AW) which is a frequently observed disorder in hot and dry climates, that leads to decline in desirable fruit quality. Color, antioxidant, and mineral contents of the arils are of prime importance as quality traits. Therefore, this study aims to investigate the effect of shading and foliar minerals on fruit quality during the fruit development stages of pomegranate. Treatments included shaded (50% green net) and unshaded trees and foliar application of trees with potassium sulfate (K, 1% and 2%) or sodium silicate (Si, 0.05, 0.1 and 0.15%) during two growing seasons. Results showed that the severity of AW at harvest decreased significantly when trees were covered with shading compared to control. The color values of L* and ⁰hue for arils were lower in fruits grown under shading conditions indicating darker red arils. Shading significantly reduced chilling injury in cold storage compared to open field fruits. Shading and Si 0.15% increased superoxide dismutase, and catalase enzymes activity while decreased Polyphenol oxidase and peroxidase. Covering trees with shading and Si 0.15% spray resulted in the highest total anthocyanin, antioxidant activity, and total phenolics content in the arils. Shading as well as Si 0.15% increased macronutrients content of the arils. The study concluded that covering pomegranate trees and spraying with Si in hot climate reduced AW, increased antioxidant traits, and led to higher fruit quality.

Effect of Shade and Light-Curing Intensity on Bulk-Fill Composite: Heat Generation and Chemo-Mechanical Properties (In Vitro Study)

The aim of this study is to assess the effect of shade and light-curing intensity on the heat generation and degree of conversion of bulk-fill composite. A commercially available bulk-fill composite resin was used in this study. A total of 250 cylindrical specimens of each composite shade (n = 25/group) were prepared (125 for testing heat generation and 125 for testing degree of conversion, then cured using a monowave light-curing unit (LCU) with a single light intensity of 1470 mW/cm2 and a polywave LCU with three different light intensities (1200, 2000, and 3000 mW/cm2). Heat generation during polymerization was measured by five K-type thermocouples placed in each 1 mm layer from top to bottom. FTIR was used for evaluating the degree of conversion. Regarding heat generation, significant differences were seen in layers 4 and 5. Curing types and times also showed significant impacts on heat generation and the degree of conversion. Heat generation relates more to curing time than light intensity. Darker shades generate and retain more heat. Lighter shades exhibit higher degrees of conversion with longer curing.

Long-term patterns and mechanisms of plant invasions in forests: the role of forest age and land-use history

It has become increasingly apparent that even mature forests are susceptible to plant invasions. However, invasive plants are often more abundant in younger forest stands. It is difficult to disentangle possible mechanisms that would explain this pattern due to the scarcity of long-term studies in successional forests. Several mechanisms have been proposed to explain patterns of invasions as forests age, including biotic resistance, window of opportunity, historical legacies, and invasion debt. We explored patterns and potential mechanisms of plant invasions over 70 years in a regenerating forest with different land-use histories in the Bolleswood Natural Area, Connecticut, USA. We examined how environmental factors related to colonization patterns of invasive and non-invasive introduced species over time, and whether these patterns were consistent with the proposed mechanisms. Non-invasive introduced species declined rapidly with canopy closure, while many invasive plants persisted or even increased over time as the forest aged. Colonization was focused in younger post-agricultural areas, although this declined with time. Dispersal distance, soil conditions, and land-use history played important roles in patterns of colonization, while the effect of shading was less clear. There was some evidence for each mechanism, but the relative importance of each mechanism was species-dependent, making generalizations about how invasive plants invade forests difficult. We found that land-use history impacted invasion more strongly than forest age, but over time even mature forests were slowly being invaded by some species. Thus, invasive species management may be required even in mature forests.

A comprehensive assessment of photosynthetic acclimation to shade in C4 grass (Cynodon dactylon (L.) Pers.)

BackgroundLight deficit in shaded environment critically impacts the growth and development of turf plants. Despite this fact, past research has predominantly concentrated on shade avoidance rather than shade tolerance. To address this, our study examined the photosynthetic adjustments of Bermudagrass when exposed to varying intensities of shade to gain an integrative understanding of the shade response of C4 turfgrass.ResultsWe observed alterations in photosynthetic pigment-proteins, electron transport and its associated carbon and nitrogen assimilation, along with ROS-scavenging enzyme activity in shaded conditions. Mild shade enriched Chl b and LHC transcripts, while severe shade promoted Chl a, carotenoids and photosynthetic electron transfer beyond QA− (ET0/RC, φE0, Ψ0). The study also highlighted differential effects of shade on leaf and root components. For example, Soluble sugar content varied between leaves and roots as shade diminished SPS, SUT1 but upregulated BAM. Furthermore, we observed that shading decreased the transcriptional level of genes involving in nitrogen assimilation (e.g. NR) and SOD, POD, CAT enzyme activities in leaves, even though it increased in roots.ConclusionsAs shade intensity increased, considerable changes were noted in light energy conversion and photosynthetic metabolism processes along the electron transport chain axis. Our study thus provides valuable theoretical groundwork for understanding how C4 grass acclimates to shade tolerance.

Assessment of the estimation methods of Tmrt in semi-outdoor spaces in humid sub-tropical climates: An empirical study in Wuhan, China

Studies have been conducted on the mean radiant temperature (Tmrt) estimation methods using globe thermometers for measuring outdoor thermal environments in various climate regions. Yet, given the unique thermal environments of semi-outdoor spaces, these Tmrt estimation methods may not be appropriate for the spaces with shading effects. This study aims to assess the thermometric and radiative methods for Tmrt estimation in semi-outdoor spaces in humid sub-tropical climates, taking data from six-directional radiation measurements as validations. During the typical summer and winter days in Wuhan, China, the measurements were carried out in semi-outdoor spaces facing south and west, with an open square for comparison, including air temperature, humidity, wind velocity, black-globe temperature, and long- and short-wavelength radiation fluxes obtained from four-component net radiometers. It was found the maximum mean deviation of diurnal Tmrt values estimated by the black-globe thermometer method in semi-outdoor spaces was 7.1 °C, which exceeded the threshold required by ISO7726, where the shortwave radiation was regarded as the dominant interference factor. To improve the accuracy and cost-effectiveness of Tmrt estimation, we proposed linear empirical equations to calibrate the Tmrt estimated by black-global thermometer method that the root mean square error (RMSE) of the Tmrt deviations can generally vary from 2.22 to 2.72 °C. Contributing to the thermal comfort research, this study proposed an empirical method for estimating Tmrt in semi-outdoor spaces in humid subtropical climates, which can generate satisfactory results in accordance with ISO7726 standards with cost-effective instrumentation.

Leveraging dynamic power benchmarks and CUSUM charts for enhanced fault detection in distributed PV systems

Faults in photovoltaic (PV) systems are common during their operational lifetime. Existing PV fault detection methods, which are primarily designed for large-scale PV fields, struggle with distributed systems due to their reliance on on-site weather sensors and inability to handle complex local shading effects on PV performance in the built environment. This paper presents a fault detection scheme specifically applicable to distributed PV systems that solely relies on monitored AC output and remote weather sources. Without requiring additional equipment or detailed information on the PV configuration and local shading conditions, the proposed method consists of two steps. First, historical monitoring data is used in a bootstrap fashion to develop machine learning models that establish baselines for normal PV output and corresponding estimation uncertainty. Then, a dynamic PV power benchmark constructed based on the 3-sigma rule, and cumulative sum (CUSUM) control charts are employed simultaneously to detect system malfunctions. Through experimental verification on actual distributed PV systems, the effectiveness of the proposed method is assessed for four categories of frequently observed malfunctions. The comprehensive experimental results indicate the considerable efficiency of the proposed sensorless method in detecting both serious PV malfunctions and minor faults with a severity as small as 4.2%.

On-grid optimal MPPT for fine-tuned inverter based PV system using golf optimizer considering partial shading effect

Improving photovoltaic systems to better withstand variations in temperature and irradiance, lessen steady-state ripples, maintain high efficiency, require less tracking time, and have minimal complexity is becoming increasingly important. The PV array's overall power output is negatively impacted by partial shading because the shaded cells produce less power and consume less power overall, which lowers efficiency and creates localized hotspots. Although bypass diodes may be used to counteract these impacts by rerouting current around cells that are shaded, they can result in several peaks, which complicates maximum power point tracking (MPPT). To manage several peaks and optimize power output, metaheuristic algorithms are compulsory. A recently developed game-based optimization methodology known as Golf Optimization Approach (GOA) is used in this study to find a way to MPPT in a grid-connected photovoltaic (PV) system under partial shading conditions (PSCs). Additionally, the same suggested approach is applied to get optimal parameters for the inverter with the goal of optimizing its voltage and current regulators. It aims to evaluate a plan to lower the output voltage and current's total harmonic distortion and DC voltage error. The proposed technique is contrasted to other tracking approaches such as the traditional Perturb & Observe (P&O), Gray Wolf Optimization (GWO), and Sea-gull Optimization Approach (SOA). Simulation is performed in MATLAB R2022b/SIMULINK environment. The obtained outcomes demonstrate the ability of the suggested technique to enhance the utility grid's power quality and improve the tracking system under various partial shading effects and temperature alterations. The proposed technique achieves a tracking efficiency of 99.8 %, surpassing the effectiveness of both of the previous methods which are at 97.2 % and 96.7 %.

Bark beetles on logging residues of European larch: Effects of shading and diameter of logging residues on infestation density

Abstract Ips cembrae, an important pest of European larch (Larix decidua), has caused local outbreaks in the last two decades and is becoming increasingly important as the proportion of European larch in forests increases. In 2021–2023, larch logs and piles of branches were placed into shaded forest and sunlit areas every month to study bark beetle species on logging residues. After adult emergence, the logs and branches were debarked, and the infestation density of bark beetles was analysed. The results indicate that shading, log diameter and top/bottom parts of log had a significant effect on infestation density of I. cembrae on logs. The infestation density of I. cembrae was higher on logs felled between December and June than on logs felled between July and November. Shading of branches was the most significant variable affecting the bark beetle species composition on branches. All four of the bark beetle species recorded were affected by diameter of the branches. Ips cembrae primarily infested sunlit branches while Cryphalus intermedius preferred shaded branches. In contrast, the infestation densities of Pityogenes chalcographus and Pityophthorus pityographus seemed to be affected primarily by moisture content of the branches.

Outdoor evaluation of total cross-tied Si module under driving conditions

This paper presents the fabrication and evaluation of a total cross-tied (TCT) Si module designed to mitigate the partial shading effect, which is known to reduce the output performance of vehicle-integrated photovoltaic (VIPV) modules. The TCT module, consisting of 27 Si solar cells interconnected both vertically and horizontally, demonstrated an 18.8 % decrease in output power when one cell was shaded. In contrast, the output of the series-parallel (SP) Si module decreased by 31.6 % under the same shading condition. Comparative analysis of the output performances of TCT, SP, and single-string commercial modules under three driving conditions revealed that increasing the number of strings helped alleviate the impact of partial shading. Notably, the TCT module configuration showed a positive impact on mitigating the partial shading effect.

Performance enhancement and techno-economic analysis of photovoltaic modules under dynamic weather conditions using dual exponential sawtooth method

The maximum output power extracted from the Photovoltaic (PV) modules is mainly dependent on ambient temperature and solar irradiance. The photovoltaic modules performance is hugely influenced by the Partial Shading (PS) effect, which results in the reduction of output power. It is caused by shadows of buildings, trees, moving clouds and towers. Under PS conditions, shaded modules receive less irradiance as compared to the unshaded modules, and this leads to overheating of PV array. The present work has been developed by a technique based on Dual Exponential Sawtooth (DES) pattern to reconfigure the PV modules so as to increase the PV output power under PS conditions along with the energy savings and economical aspects. In this technique, the PV modules of Total Cross Tied (TCT) technique and their physical locations are arranged as per DES pattern to distribute the shading effect over the entire array without altering the electrical connections of the PV modules. The DES arrangement gives the enhanced power of 41.48% by reducing the effect on any row of the shaded modules. Further, it provides the details about power sharing percentage as the number of shaded modules increase and also the affect of dynamic shade variation over the entire PV array. The proposed method validation with the existing methods for the analysis, simulation and hardware experimentation shows better performance in terms of mismatch losses and fill factor. Further, the analysis has been extended for units generated and energy savings with each module rating of 1.5KW on 4×4 PV modules.

Physiological Characteristics and Transcriptomic Responses of Pinus yunnanensis Lateral Branching to Different Shading Environments.

Pinus yunnanensis is an important component of China's economic development and forest ecosystems. The growth of P. yunnanensis seedlings experienced a slow growth phase, which led to a long seedling cultivation period. However, asexual reproduction can ensure the stable inheritance of the superior traits of the mother tree and also shorten the breeding cycle. The quantity and quality of branching significantly impact the cutting reproduction of P. yunnanensis, and a shaded environment affects lateral branching growth, development, and photosynthesis. Nonetheless, the physiological characteristics and the level of the transcriptome that underlie the growth of lateral branches of P. yunnanensis under shade conditions are still unclear. In our experiment, we subjected annual P. yunnanensis seedlings to varying shade intensities (0%, 25%, 50%, 75%) and studied the effects of shading on growth, physiological and biochemical changes, and gene expression in branching. Results from this study show that shading reduces biomass production by inhibiting the branching ability of P. yunnanensis seedlings. Due to the regulatory and protective roles of osmotically active substances against environmental stress, the contents of soluble sugars, soluble proteins, photosynthetic pigments, and enzyme activities exhibit varying responses to different shading treatments. Under shading treatment, the contents of phytohormones were altered. Additionally, genes associated with phytohormone signaling and photosynthetic pathways exhibited differential expression. This study established a theoretical foundation for shading regulation of P. yunnanensis lateral branch growth and provides scientific evidence for the management of cutting orchards.

Optimal orientation of efficacy metal fins to enhanced freshwater generation in solar distillers: An experimental study

The pressing issue of water scarcity in remote regions has stimulated the search for simple desalination techniques. Solar distillers represent one of the most important solutions in remote regions for producing freshwater, but they have low productivity. The efficient iron fins represent an effective solution to improve their freshwater productivity. However, due to the negative effect of the shadow resulting from the metal fins, the present study aims to obtain the optimal orientation of efficacy metal fins that achieves the highest productivity for solar stills. To achieve this, three solar distillers were designed and built with identical dimensions. The first distiller has vertically oriented iron fins incorporated with its basin. The second distiller has 45° inclined iron fins incorporated with its basin. But the third distiller is devoid of any iron fins and represents the reference case. Our findings revealed that the inclusion of iron fins, particularly inclined ones, significantly enhanced the yield of the solar still by 48.94 %. In contrast, the enhanced distiller with vertical fins showcased a 33.84 % increase in productivity compared to the reference distiller. Based on these results, we recommend adopting the 45° inclined metal fins to mitigate shading effects and achieve the highest productivity.

Effect of shading on agronomic and structural characteristics of Mombaça grass in agroforestry system in the Cerrado-Amazon ecotone

The search for sustainability in integrated production systems is a constant challenge, especially when it comes to balancing the levels of shading provided by trees in agroforestry systems. The objective of this study was to evaluate the effects of three shading levels (0, 30 and 60%) casted by native Babaçú trees (Attalea speciosa, Mart) on the agronomic and structural characteristics of Mombaça grass in the ecotone Cerrado-Amazon. A total area of 3 ha was stratified into 36 subdivisions measuring 270 m² each, in order to collect agronomic samples from the three shading levels, totaling 108 experimental units, where the structural and agronomic characteristics of Mombaça grass were assessed. Increased shading leads to reduction in tiller population density, forage volumetric density, leaf area index and yield and proportion of morphological components of Mombaça grass, reducing forage yield. The 65% and 78% reduction in tiller population in areas with 30 and 60% shading, respectively, in comparison to full sun light exposure, was the main factor in the reduced productivity of the grasses managed in the agropastoral system. Therefore, Mombaça grass should be managed at a level of 30% shading, which can be considered adequate to maximize forage yield, balancing the benefits of soil and water conservation with the possible negative impacts on forage production. Keywords: Integrated systems, Megathyrsus maximus, sustainability, tillering, tropical forage.

Thermal imaging can reveal variation in stay-green functionality of wheat canopies under temperate conditions.

Canopy temperature (CT) is often interpreted as representing leaf activity traits such as photosynthetic rates, gas exchange rates, or stomatal conductance. This interpretation is based on the observation that leaf activity traits correlate with transpiration which affects leaf temperature. Accordingly, CT measurements may provide a basis for high throughput assessments of the productivity of wheat canopies during early grain filling, which would allow distinguishing functional from dysfunctional stay-green. However, whereas the usefulness of CT as a fast surrogate measure of sustained vigor under soil drying is well established, its potential to quantify leaf activity traits under high-yielding conditions is less clear. To better understand sensitivity limits of CT measurements under high yielding conditions, we generated within-genotype variability in stay-green functionality by means of differential short-term pre-anthesis canopy shading that modified the sink:source balance. We quantified the effects of these modifications on stay-green properties through a combination of gold standard physiological measurements of leaf activity and newly developed methods for organ-level senescence monitoring based on timeseries of high-resolution imagery and deep-learning-based semantic image segmentation. In parallel, we monitored CT by means of a pole-mounted thermal camera that delivered continuous, ultra-high temporal resolution CT data. Our results show that differences in stay-green functionality translate into measurable differences in CT in the absence of major confounding factors. Differences amounted to approximately 0.8°C and 1.5°C for a very high-yielding source-limited genotype, and a medium-yielding sink-limited genotype, respectively. The gradual nature of the effects of shading on CT during the stay-green phase underscore the importance of a high measurement frequency and a time-integrated analysis of CT, whilst modest effect sizes confirm the importance of restricting screenings to a limited range of morphological and phenological diversity.

The effect of shade and drought on the growth and proline content of Medinilla speciosa and Medinilla verrucosa plants

Abstract Medinilla is a cultivated wild plant because it has medicinal properties. This research aims to determine the level of resistance and growth of Medinilla speciosa and Medinilla verrucosa plants in drought and shade conditions. The research was carried out in April 2022 – April 2023 in Pakem District Sleman Regency. Analysis of proline and chlorophyll content was carried out at the Gadjah Mada University Laboratory. This study used a nested complete factorial randomized block design, with the types of Medinilla speciosa, Medinilla verrucosa and the volume of water given, 1750 ml, 1500 ml, 1250 ml per polybag nested in 25%, 50% and 75% shade. Each treatment was repeated three times, resulting in a total sample of 54 plants. The results of the study showed that the volume of water provided in the shade suppressed growth, that is number of leaves, leaf area, root volume, fresh weight of stover, chlorophyll except plant height, dry weight of stover and proline content. Water is one of the essential factors needed by plants to grow and develop well. Appropriate light intensity impacts plant growth and production. Light intensity stress and water supply volume stress are part of abiotic stress that can affect growth morphology productivity.

Microbial Fertilizers and Shading Contribute to the Vegetation Assembly and Restoration of Steep-Slope after Soil Spray-Sowing in the Yuanjiang Dry-Hot Valley Region

Road construction and strip mining in mountainous regions inevitably causes the destruction of vegetation and soil, leading to large ranges of exposed slopes. Although soil spray-sowing has become a promising method to accelerate community assembly in humid regions, the application of microbial fertilizers and shading in slope recovery during soil spray-sowing are rarely reported in dry-hot valleys. This study compared the effectiveness among artificial seeding, arch column + planting bags, and soil spray-sowing by slope restoration trials in the Yuanjiang dry-hot valley, southwest China. Additionally, we explored the effect of slope degrees, shade, and microbial fertilizers on seedling survival and growth after soil spray-sowing. Results indicated that soil spray-sowing displayed better species survival and growth performance than artificial seeding and arch column + planting bags. The richness, density, and height of seedlings dropped dramatically with the increasing of slope degrees after soil spray-sowing, especially when the slope degree was greater than 1. Although shading observably improved the species density, it inhibited the growth of Albizia julibrissin and Crotalaria pallida. Moreover, microbial fertilizers Penicillium chrysogenum and Bacillus aryabhattai markedly enhanced the density and growth of species Azadirachta Indica, Cajanus cajan, Indigofera cassioides, and Sophora xanthanth. Soil spray-sowing, combined with shading and microbial fertilizers, contributes to species survival and growth when the slope degree is less than 1.73 and the soil spray-sowing process coincides with the rainy season, which provides the theoretical basis and technical support for ecological restoration in the dry-hot river valley.