Percentage Of Shading Research Articles

Varying percentages of full uniform shading of a PV module in a controlled environment yields linear power reduction

Partial shading of a PV module has received much attention over the past few years, as it results in uneven cell power generation, compromising a PV system performance. Full uniform shading of a PV module has not received as much attention. This article correlates the percentage of full uniform shading of a given PV module within a controlled environment to its output power. The percentage of full uniform shading provided by shade nets was firstly determined. These shade nets are then used to cover a specific PV module (experimental system), while an identical PV module remains totally unshaded (control system). Increasing percentages of full uniform shading negatively affected the direct beam component in a linear way. Decreasing the light intensity falling on the PV model exhibited a linear increase in the percentage of output power reduction of the PV module. This is observed in that a shade net providing 36% of full uniform shading resulted in a 56% output power reduction, while a 63% full uniform shading net yielded 82% power reduction. These results hold a strong promise to improve current simulation modules that focus on determining the output power of a given PV array under specific environmental conditions or for specialised geographical locations.

Water requirements and crop coefficients of tropical forest seedlings in different shading conditions

ABSTRACT The objective was to determine the crop evapotranspiration (ETc) and crop coefficients (Kc) of tropical forest seedlings over a 135-day cycle, in the climatic conditions of the Cerrado-Amazon transitional region (11º 51’ 08 “S; 55º 30’ 56” W; altitude of 371 m). Five native species (Tabebuia impetiginosa, Tabebuia roseoalba, Handroanthus chrysotrichus, Parkia pendula and Parkia platycephala) and one exotic species (Adenanthera pavonina) were evaluated in seven shading conditions: 35, 50 and 80% black nets (Polyolefin); green Frontinet®, red ChromatiNet® and blue ChromatiNet® of 50% shading; and full sun. Reference evapotranspiration (ETo) was obtained by the Penman-Monteith FAO-56 method and the crop evapotranspiration of the seedlings (ETc) was given by daily weighing. The Kc values were obtained by dividing ETo by ETc. At 135 DAT, destructive analysis was performed to determine the leaf area. In full sun conditions, ETc varied from 3.9 (P. pendula) to 5.0 mm d-1 (T. roseoalba). The increase in the shading percentage promotes reduction in leaf area, ETc and Kc. Colored nets with 50% shading generate similar water demands.

Investigation on Dyeing Performance of Basic and Reactive Dyes Concerning Jute Fiber Dyeing

ABSTRACTThis paper includes the investigation on the dyeing performance of reactive and basic dyestuff regarding jute fiber and discusses their benefits and shortcomings. Plain woven jute fabric samples of 261 GSM were dyed with 0.5%, 1.0%, and 4.0% shade of basic and reactive dyes. Then the dyeing performance of both dyestuffs was analyzed. It has been found that exhaustion of basic dye is considerably greater than reactive dye, while this exhaustion decreases for basic dye and increases for reactive dye with the increment of respective shade percentages. This phenomenon has also been verified through the absorption curve, i.e. K/S value of fabric dyed with both dyestuffs in three different shade percentages. Again strong covalent bond is formed during the fixation of reactive dye with the cellulose of jute fiber, and at the same time no strong bond was created in case of basic dye. Finally the color fastness properties have been assessed through rubbing and washing. Both the dye classes have shown nearly similar ratings in case of dry rubbing. However, in case of wet rubbing and wash fastness to color change and color staining; the samples dyed with reactive dyes showed superior fastness ratings over the basic dyed samples.

A dynamically downscaled projection of past and future microclimates

AbstractEcological forecasting requires information about the climatic conditions experienced by organisms. Despite impressive methodological and computational advances, ecological forecasting still suffers from poor resolutions of environmental data. Published data comprise relatively few layers of surface climate and suffer from coarse temporal resolution. Hence, models using these data might underestimate heterogeneity of microclimates and miss biological consequences of climatic extremes. Moreover, we currently lack predictions about vegetation cover in future environments, a key factor for estimating the spatial heterogeneity of microclimates and hence the capacity for behavioral thermoregulation. Here, we describe microclimates and vegetation for the past and the future at spatial and temporal resolutions of 36 km (approximately 0.3°) and 1 h, respectively. We used the Weather Research and Forecasting model to downscale published, bias‐corrected predictions of a global‐circulation model from a resolution of 0.9° latitude and 1.25° longitude (approximately 100 km in latitude and 130 km in longitude). Output from this model was used as input for a microclimate model, which generated temperatures and wind speeds for 1980–1999 and 2080–2099 at various heights, as well as soil temperatures at various depths and shade intensities. We also predicted the percentage of green vegetation and the percentage of shade given the angle of the sun. These data were evaluated using several criteria, each of which shed light on a different aspect of value to researchers. The metadata describe the modeling protocol, microclimate calculations, computer programs, and the evaluation process.

Shade Effect on Growth and Productivity of Tomato and Chili Pepper

Southern U.S. states such as Texas experience high temperatures and intense solar radiation during the summer production season. Use of shadecloth is common in Spain and other Mediterranean countries and is becoming popular with homeowners or small-acreage farmers in Texas. Little information is available on the applicability of using shadecloth on tomato (Solanum lycopersicum) and chili pepper (Capsicum annuum) in the warm climate of Texas. The effects of two shade nets differing in shading intensity on growth, chlorophyll fluorescence, and photosynthesis of ‘Celebrity’ tomato and ‘Sweet Banana’ chili pepper was investigated from May to Aug. 2014. Plants were grown in 50% shade, 70% shade, or full sun. Compared with the unshaded control, tomato grown in 50% shade had similar yield and shoot fresh and dry weight and less photochemical stress. The 50% shade reduced number and weight of unmarketable tomato fruit. Similar results were obtained with chili pepper except for lower numbers of marketable fruit. The 70% shade significantly reduced yield parameters of both tomato and chili pepper. Both 50% and 70% shadecloth reduced leaf temperatures of tomato and chili pepper with variable results in June and July. Growth index [(height + width 1 + width 2) ÷ 3] of tomato and chili pepper was the highest with 50% shade, the lowest with full sun, and intermediate with 70% shade. The maximum net photosynthetic rates (Pn) of tomato determined from a Pn to light response curve supported the results on growth and yield. However, the maximum Pn of chili pepper was higher in full sun treatment compared with 50% or 70% shade. The latter two were almost identical. This one growing season study indicated that shading at 50% benefits tomato and chili pepper production in west Texas by reducing heat stress; however, a shading percentage below 50% may be better.

Dynamic photovoltaic greenhouse: Energy efficiency in clear sky conditions

This paper assesses the energy efficiency of a prototype of a dynamic photovoltaic (PV) greenhouse that has an asymmetric cross section and allows the rotation of the PV modules around their longitudinal axis throughout the day to select the degree of shading inside the structure. The goal of this research is to study the production of energy and the microclimate inside the structure with different tilt angles of the PV panels to improve the information available to support the farmers and to create a PV greenhouse capable of producing income from electrical and agricultural activity. The average values of the internal air temperature and relative humidity, measured during the hottest period and on days with clear skies, are within the optimal ranges for major vegetable species (17–27°C and 60–90%, respectively). The values of the solar radiation available for the plants were always sufficient for normal agricultural operations, except for the last two days of the experiment (values lower than 5MJm−2) in which the shading percentage analyzed was too high for normal production. When the shading percentage was highest (78%), the maximum value of PV power (102Wm−2) was recorded and when the shading percentage was equal to 0%, the minimum value of PV power (20Wm−2) was recorded. The results show that it is possible to balance the electricity production using photovoltaic panels and the agricultural production as a function of the type of crop grown, latitude, operating season, and characteristics of the greenhouse.

Effect of shading on yield, fiber quality and physiological characteristics of cotton subtending leaves on different fruiting positions

Little is known regarding to impact of simulated shading conditions on cotton yield and fiber quality at different fruiting positions. In this 2-year study, our field experiments investigated the effects of shading percentage on the cotton yield, fiber properties, photosynthesis, and carbohydrate concentrations in boll’s subtending leaves during various growing stages at different fruiting positions (FP). Net photosynthetic rate and effective quantum yield of PSII photochemistry decreased in response to shading on both FP1 and FP3 of the 7th sympodial branches, respectively. Shading also reduced sucrose and starch contents of leaves at each fruiting position. Shading decreased the number and mass of cotton bolls, the fiber strength and micronaire, while the fiber length increased at both fruiting positions. Our results suggested that shading resulted in the reduction of the cotton yield and fiber quality, which are mainly associated with the changes in boll number and alteration of photosynthesis and carbohydrate concentrations during the boll development.

Assemblage of aquaticHeteroptera (Gerromorpha andNepomorpha) in relation to microhabitats in thePhongRiver,NortheastThailand

AbstractIn this study, we explored the composition and assemblage structure of aquaticHeteroptera from 15 sampling sites along thePhongRiver,Thailand, during the rainy (July 2011), cool (December 2011) and hot (March–April 2012) seasons. A total of 8399 individuals, belonging to 54 species and 12 families of aquaticHeteroptera were recorded. TheKruskal–Wallis test indicated significant difference in total number of species and total number of individuals of aquaticHeteroptera among microhabitat types (P< 0.05). Stepwise multiple regression and canonical correspondence analysis (CCA) ordination show that characteristics of microhabitats including percentage of gravel, percentage of aquatic macrophytes covering the water surface and percentage of shading from riparian vegetation determine aquaticHeteroptera assemblage structures. From this study, microhabitats have more effect on aquaticHeteroptera than water pollution.

Examination and assessment of insolation conditions of streetscapes of traditional settlements in the Eastern Mediterranean area

Vernacular settlements are characterized by their adaptability to local climatic conditions, topography and available resources, in terms of materials and methods of construction, while, most of them incorporate various bioclimatic design concepts. The present study examines the solar conditions in traditional settlements in a Mediterranean climate, caused by topographical features and the built form. The main aim is to explore traditional planning configurations of streetscapes in different elevations in order to discern built form patterns and planning strategies that are effective in ameliorating outdoor user-comfort conditions. For this purpose, case studies are examined from three rural traditional settlements in Cyprus; an island which features a typical Mediterranean climate. The chosen settlements are selected because they represent a comprehensive cross section of the varied topographical conditions, built forms and climatic zones representative of Mediterranean regions. Streetscapes in these villages are systematically investigated in terms of monthly and quarterly insolation simulations and the results are analyzed in terms of sunlight hours, incident solar radiation, shading percentages and sky view factors. The research findings show that certain geographical characteristics affect incident solar radiation at street corridors and related building facades. It is also made evident that traditional villages in mountainous areas – due to their denser building form and deeper street corridors compared to the more dispersed built form patterns found in the lowland areas – increase local shading patterns significantly. This particular built layout in the mountainous settlements has the potential to improve outdoor thermal user-comfort conditions during the summer. In contrast, overshadowing occurs in the winter for the vast majority of street corridors in all case studies and this is usually moderated by the incorporation of widenings of the street corridors to permit solar penetration.

Effects of Water Hardness on Dyeing of Cotton Fabrics with Different Types of Reactive Dyes and Shade Percentages

This research was investigated the influence of water hardness on dyeing of cotton fabric with three types of reactive dyes (Synozol, Ramazol and Setazol). The effects of various fastness (color fastness to wash, abrasion test, Rubbing test and Perspiration test) properties of dyes were also studied and reported in this paper in details. Single color (Blue) is used for the shade of 1% and 2% and varied water hardness of 120 ppm, 70 ppm and 9 ppm respectively. The main objective of this paper was to find out the parameters of various fastness properties at different range of water hardness in the application of different types of reactive dyes. It is visualized that different amount of water hardness showed in different fastness for using three types of reactive dyes having shade of 1% and 2%. We reported that water hardness up to 9 ppm, for using three types of reactive dyes showed excellent wash fastness and it deteriorates with increasing hardness. Setazol 1% & 2%, showed highest abrasion resistance at 9 ppm water hardness compare to other dyes at higher water hardness. Rubbing test result also showed very good for 9 ppm water hardness in three reactive dyes irrespective of shade percentage. The perspiration test result is good at 9 ppm water hardness for all types of reactive dyes with all shade percentages.

A Study on the Effects of Material to Liquor Ratio on the Colorfastness of Synolon Yellow EXW Fluorescent Disperse Dye

This study highlighted the influence of change in material to liquor ratio on the colorfastness properties of Synolon Yellow EXW fluorescent disperse dye applied on knitted polyester fabric in exhaust dyeing method. Three different liquor ratios (1:6, 1:8 and 1:10) were used and dye shade percentages were 0.5%, 1.0% and 1.5%. The results showed that an increment in liquor ratios increased the colorfastness to washing (color change) for the shade percentages of 0.5 and 1.5. Wash fastness (color staining) grading was not satisfactory when material to liquor ratio is 1:6. Increasing the amount of liquor resulted least color bleeding. No color fading has been observed in dry rubbing test for 1:10 material to liquor ratio. Increment in the material to liquor ratios resulted better dry and wet rubbing fastness for both color change and color staining. Variation in the liquor ratios showed no effects on the abrasion resistance property.

Social behaviour of cattle in tropical silvopastoral and monoculture systems

Silvopastoral systems can be a good alternative for sustainable livestock production because they can provide ecosystem services and improve animal welfare. Most farm animals live in groups and the social organization and interactions between individuals have an impact on their welfare. Therefore, the objective of this study was to describe and compare the social behaviour of cattle (Bos indicus×Bos taurus) in a silvopastoral system based on a high density of leucaena (Leucaena leucocephala) combined with guinea grass (Megathyrsus maximus), star grass (Cynodon nlemfuensis) and some trees; with a monoculture system with C. nlemfuensis, in the region of Merida, Yucatán. Eight heifers in each system were observed from 0730 to 1530 h each day for 12 consecutive days during the dry season and 12 consecutive days during the rainy season. The animals followed a rotation between three paddocks, remaining 4 days in each paddock. The vegetation was characterized in the paddocks of the silvopastoral system to estimate the average percentage of shade provided. To make a comparison between systems, we used a t test with group dispersion, and Mann–Whitney tests with the frequency of affiliative and agonistic behaviours. We assessed differences in linearity and stability of dominance hierarchies using Landau’s index and Dietz R-test, respectively. The distance of cows with respect to the centroid of the group was shorter, and non-agonistic behaviours were 62% more frequent in the intensive silvopastoral system than in the monoculture one. Heifers in the silvopastoral system had a more linear and non-random dominance hierarchy in both seasons (dry season: h’=0.964; rainy season: h’=0.988), than heifers in the monoculture system (dry season: h’=0.571, rainy season: h’=0.536). The dominance hierarchy in the silvopastoral system was more stable between seasons (R-test=0.779) than in the monoculture system (R-test=0.224). Our results provide the first evidence that heifers in the silvopastoral system maintain more stable social hierarchies and express more sociopositive behaviours, suggesting that animal welfare was enhanced.

Analysis of internal shading degree to a prototype of dynamics photovoltaic greenhouse through simulation software

In recent years the use of photovoltaic panels as cover materials for greenhouses developed a great interest due to the state’s incentives obtainable by such applications. Shading caused by these elements inside the structure appears to be often too much for the normal development of agricultural activity. In this study it was analyzed the behaviour of shading caused by the photovoltaic panels inside a prototype of dynamic photovoltaic greenhouse whose particularity lies in the possibility of rotation of the panels along the longitudinal axis. The panels’ rotation allows varying shading degree in function of some parameters such as latitude and the different solar angles. In order to avoid any reflection losses due to imperfect inclination of the photovoltaic panels, 24 highly reflective aluminium mirrors were prepared with the objective of recovering the portion of solar radiation otherwise lost by reflection. For the study it was used the simulation software Autodesk® Ecotect® Analysis which allows to analyse the path of the shadows during the day and throughout the year for any latitude considered. For this study it was analyzed shading with the panels in a horizontal position. It was also analyzed the evolution of the percentage of shading simulating different latitudes. The results obtained show a great variation of the shading degree inside the structure during a single day and during the year. We can conclude that integrating this analysis with the energy balance it is possible to study the behaviour of photovoltaic greenhouses in order to integrate the energy production from renewable energy sources and agricultural production.

Seeds Capacity of Kranji ( <i>Pongamia pinnata Merril</i>. ) Tree as Renewable Energy

<p>Pongamia pinnata Merrill. (kranji / Mabai / pongam) is a coastal plant that seeds to produce bio-diesel and wood energy, spread from Sumatra to the Moluccas islands there are Kulur Laut (Central Bangka ); Sukarame, Carita (Banten), Batukaras, Ciamis (West Java), National Park Alas Purwo - Banyuwangi (East Java), Kalibukbuk (North Bali); Sambelia, East Lombok (West Nusa Tenggara) Berau, Kulkar and Paser (East Kalimantan) and West Seram (Maluku Islands). </p><p>The aim to get the character of tree, fruit distribution and potential kranji oil supply that can last all year. Because of the requirements to be a source of renewable energy is sustainable fruit production (raw material of bio-diesel). Naturally, this plant has a generative nature (flowering and fruiting) different between individuals than are affected by environmental conditions. </p><p>The results of the census data collection in a single plot observation in August 2009 in the National Park Alas Purwo, the character generative growth there between stands have a different that is 5 finished fruiting trees, 3 young fruit trees, 5 mature fruit trees (ready to harvest) and 3 trees are flowering. While the potential for actual production in the village of Batu Karas (Ciamis) in July 2010, has an average production capacity of as much as 1855 or 2297 pods per tree per tree seed grain, 1000 grain weight of 778.21 grams, the equivalent of 2.45 kg / tree the distance between the nearest tree was 2.49 ± 0.80 m. The plants bear fruit at the age of 3 years. </p><p>Planting can broadly be followed by silvicultural management based generative character of the plant so that fruit production can be sustained and followed by oil production management seed production adapted to be effective and efficient. To get the properties of its parent, this plant can be propagated by cutting the middle branch with a density of 25% gives the percent shade shoots grow by 68.4%. </p><p>Pongamia pinnata has a high potential to be developed as a plant producing bio-diesel material along the coast and on the results of the test crop can grow well in the area of the former mine (Kota Tua Tunu, Bangka) and on marginal land (Parung Panjang, Kabupaten Bogor). The plant roots can symbisis with Rhizobium for clicking of N-fixation from the air. </p><p><strong>Keyword</strong> (kata kunci) : pongamia pinnata, potential seed production, distribution </p>

ROOTSTOCK AND ET-BASED IRRIGATION EFFECTS ON MINERAL NUTRITION, YIELD AND HARVEST QUALITY OVER DIFFERENT SEASONS IN 'PACIFIC GALA' APPLE

ISHS X International Symposium on Integrating Canopy, Rootstock and Environmental Physiology in Orchard Systems ROOTSTOCK AND ET-BASED IRRIGATION EFFECTS ON MINERAL NUTRITION, YIELD AND HARVEST QUALITY OVER DIFFERENT SEASONS IN 'PACIFIC GALA' APPLE

Productivity under Shade and Different Nutrient Solution of Hydroponic Watercress (Nasturtium officinale R. BR.)

Commercialization of watercress in the Sierra Norte mountain range in Oaxaca, Mexico principally relies on harvesting plants growing on riverbanks; however, semi-intensive cultivation throughout the year could be established as an alternative for the region. With this as an objective, the present study was carried out using the laminar flow of nutrients technique to evaluate four solutions of different macronutrients and four shade percentages. Treatment distribution was formulated according to a bifactorial arrangement. Four harvest periods were employed, in April, June, September, and November of 2010. Yields and vegetative growth of watercress decreased linearly with increasing shade levels. The best results were obtained with a nutrient solution using an electrical conductivity (EC) of 0.90 dS m−1. Shade cloth percentages higher than 10% caused a significant decrease in total cycle production; the use of shade cloth is not recommended during seasons with low incident radiation.

Investigation on Physical Properties of Fluorescent Dyed Cotton Knit Fabric

This study attempted to dye the knit fabric with fluorescent dye in different shade percentages(5%,7.5% & 10% )and investigate their effects on physical properties of dyed fabrics e.g. strength, stiffness, fastness properties, k/s value, handle properties etc. Exhaust dyeing method was applied in the experiments for 100% cotton knitted fabrics. The physical properties of the dyed knitted fabrics , before and after the treatment of fluorescent dyes were determined and evaluated . Also knit dyed fabrics were compared with woven fabrics in terms of color exhaustion. This work evinces that fluorescent dye has no inauspicious effect on the physical properties of cotton knit fabric.

EFFECT OF SHADE PERCENTAGE ON VARIOUS PROPERTIES OF COTTON KNITTED FABRIC DYED WITH REACTIVE DYES

Shade percentage is an important factor which has various impacts on cotton knitted fabric. The technical factors GSM, CPI (Course per Inch), WPI (Wales per inch), shrinkage percentage, color fastness of cotton knitted fabric are influenced by various shade percentage. The main objective of this paper was to find out that various technical factors. The cotton knitted bleached fabric (plain single jersey, single lacoste, three thread fleece & rib) which were dyed by reactive dye using auxiliaries, then measured various GSM, CPI, WPI & their fastness properties of above fabric. It was observed that after increasing the shade percentage on cotton knitted fabric, GSM, CPI, WPI and shrinkage were increased, both lengthwise and widthwise shrinkage of all fabrics were occurred. It was also observed that, with the increase of shade amount decrease the color fastness of cotton knitted fabric.

VARIATION IN LINEAR DENSITY OF COMBED YARN DUE TO DYEING WITH REACTIVE DYE IN DIFFERENT SHADE PERCENTAGES

Though yarn dyeing is a significant part of wet pro cessing, it still has some major obstacles. It loses its weight as well as strength due to wet treatment. A study on the changes of lin ear density in combed yarn due to different shade p ercentages of reactive dye has been conducted and the results are statisticall y analyzed. Remazol Red RR, Remazol Yellow RR and R emazol Blue RR were used for this experiment. The study reveals that dy e shade percentage effects on the linear density ne gatively. Before 2.5% shade the yarn loss is greater and after 3.5% shade linea r density also decreases. 2.5% to 3.5% shade percen tage can be taken as the range where loss of linear density is much less tha n the other percentages. The lowest loss percentage was found for 3% shade for every dyestuff among which Remazol Red RR was the l east.

ANALYSIS OF SHADING IMPACT FACTOR ON PHOTOVOLTAIC MODULES

Photovoltaic (PV) modules are very sensitive to shading effect. Unlike a solar thermal panel which can tolerate some shading, many brands of PV modules cannot even be operated by shadow of leave which resulted in high reduction of its output power. The effect of shading on solar PV models will be evaluated by using a simulation model for simulating both the I-V and P-V characteristics curves for PV panels. Different percentages of shading are taken into consideration of this paper which is: 25%, 50%, 75%, 100%, and without shading. The irradiation and temperature are constant during test. The results are extracted using the Matlab software. A typical Kyocera- 54W and Solara-130W solar modules are used in the simulation part. The output power of models is widely decreased as the shading percentage increased. The Shade Impact Factor (SIF) is proportional to area of panels, so the systems built with big panels were more affected by shading effect.