Percentage Of Shading Research Articles

Addressing Nitrogen-rich Biomass Production Challenges in <i>Azolla microphylla</i> Cultivation from Varying Shading and Water Depth Dynamics

<i>Azolla microphylla</i>, a rapidly growing aquatic fern with the unique ability to fix atmospheric nitrogen, presents significant potential for sustainable agriculture. Despite its nitrogen-fixing prowess, challenges persist in optimizing biomass production, prompting a detailed exploration of influential factors in this study. This paper addresses the persistent challenge of optimizing nitrogen-rich biomass production in <i>Azolla</i> cultivation. Employing a split-plot experimental design, the study investigates the influential factors of shading percentage (N) and water depth (G) in <i>Azolla</i> growth, systematically ranging from 0% (full sunlight/N1) to 75% (N3) shading percentages and 2.5 cm (G1), 5.0 cm (G2), and 7.5 cm (G3) water depths. In addition to assessing growth and production outcomes, this study explores the nitrogen content in <i>Azolla</i> under three different conditions: fresh, dried, and composted <i>Azolla</i>. Findings unveil the significant influence of shading percentage and water depth on <i>Azolla</i> growth, with the N1G2 treatment identified as the optimal condition for achieving maximum biomass production. Set against the backdrop of tropical agriculture, specifically within the high temperatures in Indonesia, our study underscores the resilience of <i>Azolla</i> to elevated temperatures, highlighting its potential as a nitrogen-fixing agent. Notably, fresh <i>Azolla</i> closely matches urea in nitrogen content, suggesting its potential as an organic fertilizer substitute for urea. This research sheds light on the critical challenges surrounding nitrogen-rich biomass production from fresh <i>Azolla</i>, emphasizing the necessity of temperature resilience and water depth optimization. The insights provided hold significance for tropical agriculture practices seeking to harness the potential of <i>Azolla</i> as a free-air nitrogen fixator.

PENGARUH NAUNGAN TERHADAP PERTUMBUHAN BIBIT GAHARU (AquilariaMalaccensis) DI PERSEMAIAN JURUSAN KEHUTANAN, FAKULTAS PERTANIAN UNIVERSITAS PATTIMURA.

Agarwood (Aquilaria malaccensis) is a non-timber forest product commodity that has a high selling value. Indonesia is the largest agarwood producer in the world. By the end of 1990, Indonesia could produce more than 600 tons of agarwood annually. The research was carried out in the nursery of the Forestry Department, Faculty of Agriculture, Patimura University. This research was carried out from February to May 2024 to determine the effect of shade on the growth of gaharu seedlings (Aquilaria malaccensis). The percentage of shade supports the growth of (Aquilaria malaccensis). The experimental design used was a Completely Randomized Design (CRD) with 4 treatments, namely no shade, 50% shade, 65% shade, and 75% shade. The research results show that gaharu seeds are a semi-tolerant type, or a type of gaharu tree that can grow in open and shaded areas.

The Effect of Shade on Germination and Seedling Growth of Two Dogfruit (Pithecellobium jiringa) Genotypes

Dog fruit (Pithecellobium lobatum Benth, synonyms P. jiringa, Archidendron pauciflorum) is one of the popular tropical plants. The objectives of this research are to determine the best (i) the best genotype for germination and growth of dogfruit seedlings (ii) combination of shade and genotype, (iii) the best percentage of shade and. This research was carried out by direct observation of seed germination and seedling formation. The study was carried out in an experimental garden located ± 255 meters above sea level. The average temperature and mean humidity during the experiment were 27 ºC and 65%, respectively. The experiment used a completely random design consisting of two factors. The first factor was shade (0%, 40%, or 80% shading). The second factor was genotype (bareh and lokan). Data were analysed using analysis of variance and significant differences were further analysed using Duncan’s New Multiple Range Test at the 5% level. Observations for determining the time of radicle appearance, root length, radicular colour, and germination type seeds were germinated in seedbeds. Temperature and humidity were recorded in every observation. The best interaction with respect to leaf area is 80% shade cloth and the lokan genotype. Eighty percent shade cloth is the best for germination and growth of Dogfruit seedlings. The best genotype for germination and growth is lokan. It is recommended to use 80% shade cloth because it provides optimal growth of Dogfruit seedlings.

Conserving biodiversity in coffee agroecosystems: Insights from a herpetofauna study in the Colombian Andes with sustainable management proposal

Amphibians and reptiles are important indicators of ecosystem health, yet their populations are declining worldwide due to habitat loss and climate change. Agroecosystems, such as coffee plantations, can provide important habitat for these species. We conducted field surveys in the Sumapaz region of Colombia to identify the habitat structural variables that influence the diversity and abundance of herpetofauna in coffee crops. The canonical correspondence analysis revealed that abundance of leaf litter, leaf litter moisture, shade percentage, plantation area, and plantation age category were the most important variables for determining herpetofauna diversity. Our findings suggest that shaded coffee plantations can sustain herpetofauna diversity, and maintaining a thick layer of leaf litter is critical for establishing complex and structured animal communities. This study proposes a set of sustainable agricultural management principles to promote the existence of amphibians and reptiles in coffee crops. By adopting these practices, it is possible to prevent the decline in the population of amphibians and reptiles due to the expansion of the agricultural frontier, as seen in other coffee-growing regions. The findings of this study contribute to a better understanding of how to balance agricultural production and biodiversity conservation in the context of agroecosystems.

Global Maximum Power Point Tracking of a Photovoltaic Module Array Based on Modified Cat Swarm Optimization

The main purpose of this study was to research and develop maximum power point tracking (MPPT) of a photovoltaic module array (PVMA) with partial module shading and sudden changes in solar irradiance. Modified cat swarm optimization (MCSO) was adopted to track the global maximum power point (GMPP) of the PVMA. Upon a sudden changes in solar irradiance or when certain modules in the PVMA were shaded, the maximum power point (MPP) of the PVMA will change accordingly, and multiple peak values may appear on the power–voltage (P-V) characteristic curve. Therefore, if the tracking pace is constant, the time required to track the MPP might extend, and under certain circumstances, the GMPP might not be tracked, as only the local maximum power point (LMPP) can be tracked. To prevent this problem, a maximum power point tracker based on MCSO is proposed in this paper in order to adjust the tracking pace along with the slope of the P-V characteristic curve and the inertia weight of the iteration formula. The initial voltage for tracking commencement was set to 0.8 times the voltage at the maximum power point of the PVMA under standard test conditions. Firstly, MATLAB 2022a was used to construct the four-series, three-parallel PVMA model under zero shading and partial shading. The feedback of PVMA voltage and current was obtained, where the GMPP was tracked with MCSO. From the simulation results, it was proven that, under different shading percentages and sudden changes in solar irradiance for partial modules in the PVMA, the MCSO proposed in this paper provided better tracking speed, dynamic response, and steady performance compared to the conventional CSO.

Union Dyeing of Cotton-Silk Blended Woven Fabric Using Tanin Bio-mordant and Thyme as a Colourant

The study explores the application of tea leaf-extracted tannin as a bio-mordant and thyme extract as a natural dye on cationized silk-cotton blend fabric to enhance colour fastness and absorption. The colour strength and depth (shown as DL, Da, and Db values) on silk-cotton blend fabric were investigated in the CIE lab test. The results showed that temperature, shade percentage, and mordanting had a substantial impact on the dyeing process efficacy at DL = 30.61, Da = 11.49 and Db = 12.77. When the temperature was raised to 90 °C and the dye content was increased to 120%, the dyed sample's colour fastness (as measured by wash, rubbing, and perspiration) significantly improved, acquiring a grade of 4 to 5, which indicates good to excellent. There was a slight change in wet rubbing fastness from grade 3 to grade 4, indicating good to fair. The K/S values of the silk and cotton fibres, which ranged from 8.89 to 7.94 on average, respectively, demonstrated that the processes of bio-mordanting and cationization enhanced the absorption of dye. Tensile strength and extension increased in the weft direction to 22.19 N force and 5.21% extension at break, while the warp direction showed a fall to 6.63 N force and a rise in extension of 0.72%. FTIR spectroscopy confirmed the presence of Amino (N-H) bonds, Carbohydrate bonds (CH), Tannins, and Terpenoid phytochemicals of thyme in the dyed sample. The study highlights the potential of thyme extract as a natural dye and its benefits in improving the dyeing properties of silk-cotton blend fabric.

Thermal Evaluation of Vertical Greeneries for Building Façade with Different Orientations and Shading Percentages by Design-builder Simulation


 
 
 
 Green facades are the innovative forms of vertical greenery systems which are good strategies for urban greenery to improve the micro-climatic conditions of the area. This research study examines the benefits of cooling load by the simulation of the typical building. Design-builder energy plus simulation tool is used to estimate the annual cooling energy of the typical building which consists of three stories with four façade orientations with varying shading percentages to determine the optimum vertical greenery solution while taking shading percentage and façade direction into account. Design-builder software was validated by measuring the 24-hour temperature of the existing indirect vertical garden. The validation study was carried by using a basic linear regression model analysis using Mini tab software. Under five shading percentages (0%, 25%, 50%, 75%, and 100%), the building was designed with four orientations (North, East, South and West). As a consequence, there were twenty possible situations, each with four regions and four orientations. Each scenario's yearly annual cooling load was estimated and compared to a reference condition for a building without plants using the software. For four major orientations with varying different shade percentages, an indirect green façade with Thunbergia laurifolia was integrated. Validation results exhibit R2 value was 0.976, indicating that the model can express 97.6% of the actual data changes. In terms of economics, the building façade with 25% and 50% greenery coverage with a south orientation and 75% greenery coverage with east orientation are the best vertical greenery solutions. The ideal façade is the one that is completely covered in greenery (100%) and faces east.
 Keywords: Design-builder, Indirect green facade, Orientation, Simulation
 
 
 

Factors influencing the growth and yield of grains of paradise: extra income for farmers

The Forestry Commission of Ghana has adopted forest plantations as a strategy to ensure landscape restoration, enhance environmental quality and develop a sustainable resource base to satisfy future timber demands. Modified Taungya System (MTS) is a co-management system between the Forestry Commission and smallholder farmer that allows inter-cropping of timber and food crops. Practitioners and farmers observed decline in NTFPs from the wild, which in recent times have become a threat to source of livelihood that often contributes significantly to household incomes. NTFPs were introduced in MTS to engage farmers to protect the forest from wildfire and decreased theft incidences. However, farmers had to leave these lands because their crops were not doing well during canopy closure. Grains of Paradise amongst others were found to do well under shade but the best silvicultural practice to apply is indefinite. This study was undertaking to research and determine the best condition (tree stand spacing and percentage of shade) suitable for Grains of Paradise cultivation. Primary data were collected from the field. The results shows that Grains of Paradise can grow well and produce high yield under tree stands with a planting distance of 4 x 4m and a shade cover of 86% and. The Production of GoP should be introduced to other MTS farmers and interested farmers throughout the country as an alternative livelihood.

Natural dyeing and anti bacterial finishing of cotton fabric with extracts from Justicia schimperiana leaf extract: a step towards sustainable dyeing and finishing

ABSTRACT The use of non-toxic and eco-friendly natural dyes on textiles has received much attention due to the increased environmental awareness to avoid some hazardous synthetic dyes. In the present study, an eco-friendly approach was developed to impart colour and antibacterial properties to cotton fabrics dyed with Justicia schimperiana leaf extract as a non-toxic natural colourant. The solvent method of extraction and exhaust dyeing method was used for this study. Copper sulphate, ferrous sulphate, and alum were applied in a simultaneous -mordanting process as a mordanting agent. The effects of shade percentage, dyeing temperature, and dyeing time on the obtained colour strength of the fabrics were investigated. Optimisation of dyeing conditions was carried out using Box Behnken design of expert software. An optimum level of 3. 28 colour strength (K/S) was observed in the sample treated with a shade percentage of 50 (% o.w.f), 72 °C dyeing temperature, and 45 minutes of dyeing time. Antibacterial properties of treated fabrics were evaluated against common pathogenic bacteria, Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative). The results indicated the treated fabrics possessed desirable antibacterial properties. The washing and rubbing fastness of the dyed fabrics were also reported.

Land use alters cross-ecosystem transfer of high value fatty acids by aquatic insects

BackgroundMany aquatic insects emerge as adults from water bodies to complete parts of their life cycle in terrestrial ecosystems and are potential prey for riparian predators. The benefits of riparian predators from aquatic insects include higher contents of long-chain polyunsaturated fatty acids (PUFA) compared to terrestrial insects. Aquatic insects are therefore considered a high-quality food. Food containing high levels of PUFA can enhance growth and immune response of spiders. However, agricultural stressors like nutrient increase, pesticides and habitat degradation can affect the biomass of aquatic insects and in turn the diet of spiders. Studies quantifying the influence of land use on fatty acid (FA) profiles of emergent aquatic insects and riparian predators are lacking. We quantified differences in exports of FA, saturated FA, monounsaturated FA, and PUFA, FA profiles of aquatic insects and spiders between forested and agricultural sites over the primary emergence period within one year. The FA export to the riparian food web is crucial to understand energy fluxes between ecosystems. Furthermore, we monitored environmental variables to identify associations between agricultural stressors and FA profiles of aquatic insects and spiders.ResultsWe found differences in FA export and profiles of aquatic insects between land-use types. The quantity of total FA export via aquatic insects was lower in agricultural sites (95% CI 1147–1313 µg m−2) in comparison to forested sites (95% CI 1555–1845 µg m−2), while the biomass export was higher in agricultural sites. Additionally, in spring the PUFA export was significantly lower (up to 0.06 µg d−1 m−2) in agricultural than forested sites. Agricultural stressors explained only little variation in the FA profiles of aquatic insects, e.g., 4% for caddisflies and 12% for non-biting midges. Percentage of shading and pool habitats were identified as most important variables explaining the variation in FA profiles.ConclusionThe quality of aquatic insects as food source for riparian spiders was smaller in agricultural than forested sites, which can decrease the fitness of riparian predators. To improve our capacity to predict potential adverse effects in the riparian food web, future studies should identify the mechanisms underlying a lower PUFA content.

Crescimento vegetativo de Phalaenopsis sp. híbrido (Moon Orchid) em resposta à intensidade luminosa e concentração de fertilizantes

Abstract Orchid plants are one of the most popular floral decorative plants. Among the several species of orchids, Phalaenopsis sp. or moon orchid is popular because of its distinctive color, shape, and size. However, orchids have a slow growth rate due to their long juvenile phase; thus, culture technique modification is required to boost their growth, i.e., shading and fertilizer application. This research was carried out to obtain the best shade percentage and fertilizer concentration to increase the growth of moon orchid. The experiment was conducted from June to December 2022 at the greenhouse of Bale Tatanan Padjadjaran, Faculty of Agriculture, Universitas Padjadjaran, Jatinangor, Sumedang, Jawa Barat. The experiment used a split-plot design of eight shade and fertilizer treatments. The plants were cultivated in two shading intensities, namely 60% and 70%, then treated with four different complete foliar fertilizer compound concentrations (1, 2, 3, and 4 g L-1). The results showed that 60% shade combined with 2 g L-1 of foliar fertilizer significantly increased the leaf area and root length, whereas 70% shade combined with 4 g L-1 significantly increased the leaf area, root number and CCI of moon orchid.

Effect of shading, organic fertilizer and Gibberellic acid on the flowering growth of (Lavandula angustifolia) growing in Kalar city

The experiment was conducted in the city of Kalar for the period from April 1, 2022 to September 1. The experiment included three factors. The first factor is the percentage of shading at two levels open field and 50% lath house. The second factor was organic fertilizer for poultry (Penguin) at three levels (0, 25, 50) gm.plant-1, and the third factor was spraying with Gibberellic acid at three levels (0, 250, 500) mg. L-1. The experiment was designed according to a completely randomized design (R.C.B.D.). The results showed the following. The 0% shading treatment had a significant effect on the characteristics of the number of flower clusters (19,836 clusters per plant), the length of the flower clusters (23,327 cm), the length of the flower (7,768 cm), and the fresh weight of the flower. Inflorescence (0.390 g), and the number of flowers in one inflorescence (36,095 flowers. Pink inflorescence. Plant-1). As for the effect of organic fertilizer (Penguin), both concentrations (25 and 50 gm Plant-1) had a significant effect. Characteristics of flower spike length (23.239 and 23.217 cm). Inflorescence length (6.699, 7.133 cm), inflorescence fresh weight (0.292, 0.298 g), and number of flowers in inflorescence (30.438, 30.715 flowers. inflorescence. plant-1), respectively. As for the effect of spraying with Gibberellic acid, the concentration treatment (250 and 500 mg L-1) significantly affected the length of the flower spike (22.812 and 23.215 cm). Respectively, treatment with 250 mg.L-1 significantly affected the length of the inflorescence (6.977 cm) and the number of flowers per inflorescence (30.656 flowers.Flower-1).

The Effects of Hedgerows Shading on Soil Temperature and Gravimetric Soil Water Content

This study sets out to examine the effects of hedgerow shading on soil physical properties, specifically soil gravimetric water content and soil temperature. Analyses of both soil parameters were conducted at two locations with different shade proportion. The aim of the study was to address the links between hedgerow shading and basic physical soil properties which could be significant both for agricultural production and for ecological processes in agroecosystems. At both locations, soil samples and measurements were taken at different distances from hedgerow and in different time intervals. Diurnal shading variation at certain distances from the hedgerow on Location 1 and 2 was calculated with the software toll for Arboriculturists. At Location 1 shading is consistently high throughout the year, ranging from 76 to 100%. In contrast, shading at Location 2 varies from 1 to 25%. The results reveal that hedgerows at Location 1, do not have a statistically significant impact on gravimetric soil water content and soil temperature across the entire plot surface. Additionally, the percentage of shading is only marginally decreases with distance. Conversely, Location 2 exhibits an increase in soil temperature and a slight but (non-significant) decrease in soil gravimetric watercontent as the distance from the hedgerow increases., The total mean shading at Location 2 is considerably lower compared to Location 1, and the shading percentage declines more at the distance from the hedgerow increases. Overall, lower soil temperatures and higher gravimetric soil water content where observed at the more shaded Location 1. The research outcomes are helpful in agricultural production planning as well as in the evaluation of hedgerows for the needs of agricultural policy.

Effect of shading nets on environmental conditions and fruit abscission in quince (Cydonia oblonga L.)

The quince tree has been cultivated since ancient times in the province of Isfahan in Iran. Flower and fruit drop is one of the most important problems in the cultivation of quince in Iran. In this study, the role of shading nets as a protective factor in quince orchard was investigated to adjust climatic factors and reduce flower and fruit drop. A 20-year-old quince orchard was equipped with shading net system, and another part was compared as a control plot without shading net system in 2021 and 2022. The color of shading net and the percentage of shading were 30% green, 50% green and 50% white. According to the results, flowers opened five days later under the shading nets than outdoors. Percent fruit set, leaf length and width, number of fruits, and yield were significantly higher under the shade net than outdoors. Green 30% had the highest chlorophyll fluorescence index. The fruit set percentage and yield inside the shading nets were more than twice that outside. Total soluble solids and the abscission percentage in the control plot were more than the plot under nets. According to meteorological data, the temperature inside the shade netting was only 0.33–0.67 °Celsius lower than outside, but the radiation intensity outside the nets (30,362.44 lx) was more than two and a half times the amount of radiation under the shading nets (11,876.02 Lux). According to the obtained results, it is recommended to use the shade nets in quince orchards, where happened abscission of flowers and fruits leads to a decrease in yield. The green shade net color of 30 and 50% is recommended for orchards due to the higher chlorophyll fluorescence index, fruit set percentage, number of fruits, and yield.

Leaf character of sugar palm on various shades and concentrations of liquid organic fertilizer

Palm sugar has been developed to produce various products and raw materials for their derivatives. There is a very high morphological diversity of sugar palm plants, while the morphological identification of different sugar palm plant species in Banten province is still limited. The aim of this research is to determine the effect of different treatments, such as shade percentage, liquid organic fertilizer concentration, and a combination of both, on the properties of palm leaves. The experimental design used in this study was the 2-factor RCBD split plot with 3 levels each. The first factor is the variation of the shadow percentage, namely N0 (no shadow), N1 (55% shadow), and N2 (85% shadow). The second factor is different concentrations of liquid organic fertilizer (POC), namely P0 (0 ml/liter water), P1 (1 ml/liter water), and P2 (2 ml/liter water). The results showed that different types of shade yielded insignificant results in terms of variable number of leaves, total leaf area, and leaf greenness. The different types of liquid organic fertilizer concentration treatments and treatment combinations of shade percentage and liquid organic fertilizer concentrations did not influence any of the observed variables.Keywords: growth, organic fertilizer, palm, shade

Diversity characterization of three varieties of Cymbopogon nardus under different shade conditions

Abstract. Danata NH, Aini N, Udayana C, Setiawan A, Yamika WSD, Prambudi R. 2023. Diversity characterization of three varieties of Cymbopogon nardus under different shade conditions. Biodiversitas 24: 3574-3582. Cymbopogon nardus L. is a perennial aromatic plant distinguished for producing one of the world's most vital essential oils, citronella. This plant requires abounding sunlight to maximize the growth and quality of essential oils. The development of citronella can be implemented with an agroforestry system as an intercrop. However, the deterring factor restricting the propagation of citronella as an intercrop in agroforestry systems is the unavailability of adequate sunlight, consequently deteriorating the growth and quality of essential oils. This study investigated three varieties of C. nardus, i.e., Seraiwangi 1, Sitrona 1 Agribun, and Sitrona 2 Agribun, at distinctive shade proportions, i.e., 0%, 25%, 50%, and 75% shade. The examined parameters included the growth, physiological responses, yield, and quality of essential oils, i.e., citronellal, citronellol, and geraniol. Results demonstrate that the various types and shade percentages affect most examined parameters. The Seraiwangi 1 variety grown under 0% and 25% shade had nearly the same value, while the Sitrona 1 Agribun and Sitrona 2 Agribun varieties continued to experience declines ranging from 0%, 25%, 50%, to 75%. Nevertheless, shade extensively influences physiological responses such as photosynthetic rate and stomata width, and contrastingly there was a cipher effect on the stomata length. In the yield parameters, the oil concentration declined with the increase in shading percentage. The Seraiwangi 1 delivered superior quality of citronellal, citronellol, and geraniol compared to Sitrona 1 Agribun and Sitrona 2 Agribun varieties.

Effect of Shading Percentage and Potassium Dosages on Growth and Yield of Cutleaf Groundcherry (Physalis angulata L.)

Cutleaf groundcherry is a medicinal herbaceous plant that has not been widely cultivated. Adjustment to the light intensities supported by the fulfillment of essential macro-nutrient underlies the agronomic consideration for cropping system determination. The study aimed to examine the growth and yield of cutleaf groundcherry grown under shade nets of various shading percentages and potassium application at different dosages. A split-plot design was used for this pot experiment repeated three times. The main plot was the shading percentages (0, 25, 50 and 75), while potassium dosages (0, 60, 120 and 180 kg ha<sup>-1</sup>) were the subplot. The result showed that several growth variables were affected by the interaction between shading percentages and potassium dosage, whereas yield variables were not. Under the high level of shading, leaf number (41% to 50%), leaf area (28% to 50%), and shoot dry weight (70% to 85%) were reduced at all potassium dosages. Potassium dosage at 120 kg ha<sup>-1</sup> was required to achieve better growth under full sun or soft shading. Shading at 50% and upper significantly decreased fruit production by 30% lower fruit number, 50% to 80% lower fruit weight, and 15% lower total soluble solids (TSS). In addition, potassium fertilizer at 120 kg K<sub>2</sub>O ha<sup>-1 </sup>improved fruit weight but did not affect TSS. It can be concluded that cutleaf groundcherry is able to grow well under high intensity of light and need an adequate supply of potassium to improve growth, yield and fruit quality.

Investigation and Evaluation of Insolation and Ventilation Conditions of Streetscapes of Traditional Settlements in Subtropical China

Global warming, the urban heat island effect (UHI), and the risks of fossil fuel depletion necessitate a re-evaluation of traditional settlements that have been adapted to local climatic conditions, topography, and available resources, including materials and construction methods, through passive strategies to achieve thermal comfort. Although vernacular settlements have received considerable attention, few have examined and evaluated their streetscapes. This study investigates the impact of topographical features and architectural forms on insolation and ventilation conditions in traditional settlements in China’s southern subtropical climate. The aim is to explore traditional planning configurations of streetscapes at different altitudes to identify architectural forms and planning strategies that effectively improve outdoor users’ thermal comfort conditions. For this purpose, case studies are conducted on three traditional settlements in Lingnan; the Lingnan region has a typical subtropical climate in southern China. The chosen cases represent the main features of different topographical conditions, architectural forms, and climate zones in the Lingnan. We systematically simulated the insolation and ventilation in these settlements’ streetscapes on a monthly and quarterly basis and analyzed their sunlight hours, incident solar radiation, shading percentages, sky view factors (SVF), and wind speed. The findings show the following: (1) Specific terrains can affect streetscapes’ shading percentages and wind speed. The mountain settlement (With an average elevation of 600 m) is located on a southeast-facing slope (10° < slope < 20°). It receives an additional 10% of incident solar radiation compared to gentle terrain. (2) Compared to settlements located in coastal hills and mountainous, plain settlements have better shading and ventilation conditions in streetscapes. In terms of insolation, plain settlements have denser building configurations and narrower, elongated street corridors with a height-to-width ratio (H/W) = 1.9~5.5 (the height–width ratio value as street’s H/W (H = height, W = width); note that it is unitless), which can generate greater lower SVF (44.5%), and shading percentages (63.6%). Regarding ventilation, it is easier to create a “cool lane” (i) when the main street, oriented towards the dominant wind direction in summer, forms an angle <30° with it, (ii) when the primary street follows a NE–SW longitudinal orientation, while SE–NW horizontal streets intersect and weave through it, and (iii) with a H/W = 3~4 resulting in wind speeds of 2.9~4.0 m/s. (3) All the streetscapes have overshadowing occurring in winter; similarly, varying sizes of calm wind zones are created in summer. To alleviate these issues, widening the streetscapes along the buildings can permit solar penetration and natural ventilation. (4) In summer, installing shading devices along the horizontal plane of covered street corridors with a H/W = 1~4 and N–S longitudinal orientation can provide an additional shading of 3.6–22%.

The Improvement of Oil Palm Seedling through Shade, Manure and Organic Liquid Fertilizer in Ultisol Media

The development of oil palm nurseries in Bengkulu is constrained by plant media, such as ultisol soil, which has low nutrients. Nutrients in ultisol can be equipped by organic matters such as manure and liquid organic fertilizer (LOF). Moreover, the light intensity also could affect seeds growth. This research aimed to determine the improvement of oil palm in pre-nursery as affected by LOF, types of manure application, and shade to obtain the best treatment combination. The research was conducted from June until September 2021 in Beringin Raya, Bengkulu city. The study was arranged in a split-plot design in a completely randomized block design consisting of 3 factors with three replications. The main plot was shade percentage ((N1=50% dan N2=75%), the subplot was liquid organic fertilizer doses ((B1=0%, B2=5% and B3=10%), the sub subplot was the types of manure (P1=cow manure, P2=chicken manure, P3=goat manure, and P4= without manure). The observation was made on the growth components of oil palm seedlings until 3.5 months. There was an interaction between shade, LOF, and types of manure to the number of leaves. There was no interaction between LOF and types of manure. The shade did not affect the growth factors of the seeds. Applying 10% LOF can improve the growth of oil palm seedlings. Chicken manure has the highest variable value on the hump diameter and the number of leaves seedlings.

Mitigation of hot-spot effect via back side cooling techniques: A potential for electrical and thermal performance improvement

Hot-spot mitigation is an ever-present issue in photovoltaic system and it significantly affects the performance of photovoltaic (PV) panels. Most of the hot-spots are actually partial hot-spots which cover only a part of PV cell, or part of PV panel. In this work an influence of cooling mechanism on hot-spot mitigation is investigated by using previously developed numerical model. Specific parameters such as insolation, hot-spot intensity, convection intensity, cooling medium temperature and number of affected cells were varied for single panel. By varying parameters, it was found that partial hot-spots with less than 15% shade percentage on up to 4 cells (corresponds with 1% of total shade on PV panel) can be mitigated with adequate cooling technique applied on the PV panel. The hot-spot cases with larger shade can be mitigated, but only with high cooling intensity which makes the feasibility of the mitigation highly questionable. Hot-spot cases with more than 15% shade percentage on more than 10 affected cells (corresponds with 2.5% of total shade on PV panel) practically cannot be completely mitigated with any back side cooling technique. Nevertheless, cooling technique still provides additional electrical energy gain even with intense hot-spot cases. Results gained in this investigation can also be used to estimate potential in higher electricity output with specific cooling technique, and to estimate thermal energy potential such as house or hot water heating. A simplified case study is presented, where result application is explained step-by-step. These results are of particular interest for PV panels installed in urban areas with lots of obstructions and where regular cleaning is not practical. Such applications are rooftop PV systems, facade PV and photovoltaic-thermal (PVT) systems.