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Desempenho térmico e visual de elementos transparentes frente à radiação solar / Thermal and visual performance of transparent elements related to the solar radiationJoaquim Cesar Pizzutti dos Santos 23 August 2002 (has links)
A especificação das vedações transparentes é uma das decisões mais complexas no âmbito do projeto arquitetônico. Envolve diversos fatores construtivos e de necessidades humanas relacionadas ao conforto ambiental, associadas a uma grande variedade de produtos disponíveis no mercado. Este trabalho busca facilitar aos projetistas esse processo de especificação, fornecendo valores dos parâmetros de desempenho dos elementos transparentes em relação à análise do conforto térmico e visual, coerentes com a realidade climática brasileira e com a real incidência da radiação solar ao longo do dia. Foram estudados os vidros comuns, laminados e refletivos, e as películas de controle solar, policarbonatos e acrílicos usados em edificações no Brasil. Foi utilizada a análise por espectrofotometria para a obtenção dos valores de refletância, transmitância a absortância para as diferentes regiões do espectro solar, com ângulos de incidência variados. A partir do relacionamento desses resultados, considerando o comportamento similar de variação do Fator do Calor Solar (FCS) e da Transmitância da Luz Visível (Tv) com o ângulo de incidência, foi desenvolvida uma metodologia que possibilita o cálculo simplificado de ganhos de calor e luz natural. / The specification of the transparent elements is one of the most complex decisions in the ambit of the architectural project. It involves several constructive factors and human necessities related to the environmental comfort, associated to a great variety of available products in the market. The aim of this work is to facilitate the specification process to the planners, supplying values of the performance parameters of the transparent elements in relation to the analysis of thermal and visual comfort, coherent with the Brazilian climatic reality and with real incidence of the solar radiation along of the day. It were studied the ordinary, laminate and reflective glasses, the solar control films, policarbonates and acrylic used in Brazilian constructions. The spectrophotometry analysis was used to obtain the reflectance, the transmittance and the absortance values for the different regions of the solar spectrum, with varied incidence angles. Starting from the relationship of those results, considering the similar behavior of variation of the Solar Heat Factor (FCS) and of Transmittance of the Visible Light (Tv) with the incidence angle, it was developed a methodology that facilitates the simplified calculation of heat and natural light gains.
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Dimensionamento e analise termica de um dessalinizador solar hibrico / Sizing and analysis of a hybrid solar dessalinizadorLopes, Joaquim Teixeira 02 March 2004 (has links)
Orientador: Waldemir Silva de Lima / Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-03T22:41:40Z (GMT). No. of bitstreams: 1
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Previous issue date: 2004 / Mestrado / Refrigeração e Condicionamento Ambiental / Mestre Profissional em Engenharia Mecanica
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Utilização de malhas coloridas na produção de flores de alta, media e baixa exigencia em radiação solar / Use of coloured nets for growth of flowers with high, medium and low requirement of solar radiationLeite, Cicero Alexandre 06 January 2006 (has links)
Orientadores: Maria Angela Fagnani / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-07T22:58:20Z (GMT). No. of bitstreams: 1
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Previous issue date: 2006 / Doutorado / Agua e Solo / Doutor em Engenharia Agrícola
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Uso da solarização na redução de microrganismos patogênicos no efluente domésticoEliana Maria de Araújo Mariano da Silva 13 September 2007 (has links)
Solarização é uma alternativa para desinfecção de águas residuárias, pois a ação conjunta dos raios solares e da temperatura tende a inibir o crescimento de microrganismos. O objetivo desta pesquisa é verificar a eficácia do método na redução de microrganismos patogênicos em amostras de efluente doméstico. O experimento foi desenvolvido em condições de campo nos meses de julho, agosto, outubro e dezembro de 2006 e março e julho de 2007, na área da estação meteorológica localizada na Fazenda Piloto da Universidade de Taubaté. A análise de coliformes fecais e a leitura de turbidez foram realizadas no laboratório de Microbiologia Agrícola e Fitopatologia do Departamento de Ciências Agrárias da Universidade de Taubaté. A temperatura do ar e a intensidade da radiação solar total acumulada foram fornecidas pela Plataforma de Coleta de Dados (PCD) uma parceria UNITAU e INPE através do Programa de Monitoramento Ambiental da Região do Eixo Rio-São Paulo. As amostras de efluentes foram condicionadas em 20 garrafas transparentes com capacidade para 2L tipo PET (Politereflato
de Etileno), depois submetidas aos seguintes procedimentos: sem exposição ao sol e com 2, 4, 6 e 8 horas de exposição ao sol, com 4 repetições cada, totalizando 20 recipientes. A eficiência do tempo de exposição foi determinada pela quantificação do Número Mais Provável (NMP) para coliformes fecais nas amostras de efluentes. Quanto ao resultado podese
observar que a exposição do efluente a radiação solar reduziu a ocorrência de coliformes fecais, na medida em que se aumentou o tempo de exposição. Sendo que para 2 horas de exposição à radiação solar houve uma redução média de 51,2% e com 8 horas de exposição essa média aumentou para 84% de redução para coliformes fecais. De acordo com os resultados pôde-se concluir que a solarização poderá ser utilizada para reduzir microrganismos patogênicos no efluente doméstico. / Solarization is an alternative method for disinfection of wastewater, therefore the joint action of the solar rays and the temperature tends to inhibit the growth of microorganisms. The objective of this research is to verify the effectiveness of the method for the reduction of pathogenic microorganisms in domestic effluent samples. The experiment was developed in field conditions during the months of August, October and December of 2006 and March and
July of 2007, in the area of the meteorological station located in the Pilot Farm of the University of Taubate. The fecal coliform counts and the turbidity readings were performed in the Agricultural Microbiology and Phytopathology Laboratory of the Agrarian Sciences Department of the University of Taubate. The air temperature and the intensity of the accumulated total solar radiation had been supplied by the Data Collection Platform (DCP), a
partnership between UNITAU and INPE for the Program of Environmental Monitoring of the Rio-Sao Paulo Region. The effluent samples had been placed inside of 20 transparent 2-liter disposable bottles, and than submitted to the following procedures: without exposition to the sun and with 2, 4, 6 and 8 hours of exposition to the sun, four repetitions each, totalizing 20 experiments. The efficiency of the exposition time was determined by the fecal coliform
counts in the effluent samples enumerated by the most probable number (MPN) method. It can be observed reduction of fecal coliform counts with the exposition of the effluent to the solar radiation, and this reduction was proportional to the increasing of the exposition time. It was observed an average reduction for fecal coliform counts of 51,2% with 2 hours of solar radiation exposition, and this average reduction increased to 84% with 8 hours of exposition. The results showed that the solarization can be used as a method for reduction of pathogenic microorganisms in the domestic effluent.
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Microclima e produção de tomate tipo cereja em ambientes protegidos com diferentes coberturas plásticas / Microclimate and cherry tomato production in greenhouses with different plastic coversHolcman, Ester 03 February 2010 (has links)
Em regiões de intensa disponibilidade de energia solar e elevadas temperaturas, os produtores de tomate procuram limitar a radiação no interior dos ambientes protegidos para reduzir a temperatura, principalmente por meio de malhas aluminizadas. Porém, o uso dessas malhas provoca redução demasiada na transmitância da radiação fotossinteticamente ativa, trazendo conseqüências negativas à produtividade. Desse modo, é importante se caracterizar o microclima desses ambientes em função da cobertura empregada. O presente estudo teve por objetivo avaliar a influência de diferentes coberturas plásticas em ambientes protegidos no seu microclima e na produtividade e qualidade do tomateiro tipo cereja. Para tanto, um ambiente protegido de 50 m, instalado em Piracicaba, SP, foi dividido em dois ambientes distintos: Ambiente I - coberto com filme plástico anti-UV e com uma malha termo-refletora e Ambiente II - coberto com filme plástico difusor. Nesses ambientes foram cultivadas, em duas épocas distintas, duas cultivares de tomate tipo cereja (Sweet Grape e Sweet Million), submetidas a diferentes soluções nutritivas (relação K:N 2:1 e 3:1) na fertirrigação. No Ambiente II houve maior transmitância da radiação solar, sendo 50,3% superior à transmitância observada no Ambiente I. A temperatura média do ar no Ambiente II foi 5,2% e 2,1% superior à temperatura no ambiente externo, respectivamente para o 1º e 2º ciclo. Já no Ambiente I, as temperaturas foram praticamente iguais às observadas externamente. A cultivar Sweet Grape produziu maior quantidade de frutos pequenos (163 frutos pl-1) e grandes (341 frutos pl-1) do que a cultivar Sweet Million (102 e 261 frutos pl-1, respectivamente). A solução nutritiva com relação 2:1 de K:N promoveu maior produção de frutos pequenos (144 frutos pl-1) do que a relação 3:1 (122 frutos pl-1). As plantas no Ambiente II produziram, em média, 146 frutos pequenos por planta e 368 frutos grandes por planta, enquanto que no Ambiente I essa produtividade foi de 119 e 235 respectivamente. Os diferentes ambientes não tiveram influência sobre o diâmetro dos frutos, no entanto, promoveram diferenças no peso desses. Os frutos pequenos e grandes no Ambiente II pesaram respectivamente 6,66 g e 11,91 g e no Ambiente I 6,09 g e 11,21 g. A cultivar Sweet Million produziu 4,58 kg pl-1 e 3,85 kg pl-1 e a cultivar Sweet Grape produziu 3,94 kg pl-1 e 3,53 kg pl-1 nos 1° e 2° ciclos, respectivamente. Quanto à qualidade do fruto, o ambiente influenciou somente a porcentagem de acidez e o teor de vitamina C. A relação K:N 2:1 promoveu valor médio de oBrix ligeiramente superior ao valor obtido com a solução 3:1. Os frutos da cultivar Sweet Million apresentaram maior acidez e maior teor de vitamina C do que a cultivar Sweet Grape. Com base nesses resultados, concluiu-se que a cobertura com o filme plástico difusor foi eficiente em manter a temperatura e a radiação solar em níveis adequados para uma boa produtividade e qualidade das cultivares de tomateiro tipo cereja estudadas. / In the regions where solar energy is very intense and temperatures are high, the tomato growers use to reduce the incoming solar radiation inside the greenhouses, aiming to promote the temperature reduction, mainly by installing aluminated shading screens inside. However, the use of such covers promotes an intense reduction of the photosynthetic active radiation, bringing negative consequences for yield. Therefore, it is important to characterize the microclimate inside the greenhouses in relation to the cover material used. Based on that, the objective of the present study was to evaluate the influence of different covers on microclimate and the cherry tomato yield and quality in greenhouses, in Piracicaba, state of São Paulo, Brazil. For that, a 50-m greenhouse was divided in two different environments: Environment I - covered with plastic film anti-UV and with thermo-reflective shading screen disposed internally, and Environment II - covered with diffusive plastic film. Both environments were cultivated with two cultivars of cherry tomato (Sweet Grape and Sweet Million), fertilized with two different solutions (K:N relation of 2:1 and 3:1) by fertirrigation. Environment II had 50.3% more availability of solar energy than Environment I. The temperature inside Environment II was slightly higher (5.2 and 2.1% in the first and second cycles) than Environment I, which had similar temperatures to outside condition. The Sweet Grape cultivar produced more small (163 fruit pl-1) and large (341 fruit pl -1) fruits than Sweet Million (102 and 261 fruits pl-1, respectively). The 2:1 K:N solution promoted greater production of small fruit (144 fruit pl-1) fruits than 3:1 (122 fruit pl-1). Plants in the Environment II produced, in average, 146 small fruits per plant and 368 large fruits per plant, whereas the ones in Environment I produced 119 and 235 fruits per plant, respectively. The different environments did not have influence on fruit diameter; however, they promoted differences in the weight of the fruits. Small and large fruits in the Environment II weighted 6.66 g and 11.91 g and in the Environment I they weighted 6.09 g and 11.21 g, respectively. Sweet Million cultivar produced 4.58 kg pl-1 and 3.85 kg pl-1 and Sweet Grape 3.94 kg pl-1 and 3.53 kg pl-1 respectively in the 1st and 2nd cycles. In relation to fruit quality, the environment had influence only on the percentage of acidity and vitamin C content. The ratio K:N 2:1 resulted in a small °Brix difference in relation to the ratio 3:1. The Sweet Million fruits had higher acidity and vitamin C content than Sweet Grape ones. Based on these results, it is concluded that the cover of Environment II (diffusive plastic film) was efficient to keep the temperature and solar radiation in favorable levels for high productivity and quality of both cherry tomato cultivar during the two seasons evaluated.
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Modeling the formation, evolution, and observation of first starsKulkarni, Mihir Sanjay January 2021 (has links)
Population III (Pop III) stars are the first generation stars forming after the big bang from primordial gas. This dissertation is focused on the various processes that suppress and delay the formation of Pop III stars in the universe and their implications for the observations. We studied the impacts of the Lyman-Werner (LW) radiation that dissociates molecular hydrogen, baryon-dark matter streaming velocity introduced at recombination, ionizing radiation from nearby galaxies, and a model for the composition of dark matter known as the fuzzy dark matter on the formation of Pop III stars.
Firstly, we take a closer look at the critical halo mass (Mcrit) that is the typical minimum dark matter halo mass needed to host cold dense gas to form the first stars using cosmological hydrodynamical simulations. LW radiation that dissociates molecular hydrogen and the baryon-dark matter streaming velocity both delay the formation of Pop III stars by increasing the critical halo mass. We describe our simulation suite with varying levels of LW radiation and streaming velocity to provide a fit for Mcrit as a function of LW radiation, streaming velocity, and redshift which can be used in semi-analytic models of early galaxy formation to make predictions for observations.
Secondly, we explore a possible mechanism for the formation of large clusters of Pop III stars: a nearby ionizing source that ionizes a late forming halo, delaying its collapse until the halo is sufficiently large enough that the core can self-shield and suffer runaway collapse. We use numerical simulations to examine the fragmentation of the gas near the runaway collapse using the simple estimates and sink particles to show that the number of fragments is generally small, at most a handful, and that the mass accretion rate on the fragments is of order 10⁻³ Msun/yr. This rate is sufficiently high enough that the descent on the main sequence (and hence the suppression of accretion) is delayed until the stellar masses are of order 100-1000 Msun, but not high enough to produce direct collapse black holes of mass ~ 10⁵ Msun. The resulting clusters are larger than those produced in minihalos but are still likely to fall short of being easily detectable in James Webb Space Telescope blind fields.
Finally, we investigate the formation of the first stars and galaxies in a fuzzy dark matter cosmology. Fuzzy dark matter, made up of ultra-light axions of mass ~ 10⁻²² eV, is a proposed alternative to the standard cold dark matter to solve its apparent small-scale problems. Its large de Broglie wavelength, of the order of kpc, results in the suppression of small-scale matter power, thus delaying the formation of the first stars and galaxies to lower redshift in much more massive halos. Therefore, first stars can be used to put very strong constraints on the mass of the fuzzy dark matter. We describe our cosmological simulations that accurately evolve the fuzzy dark matter distribution to study the formation of the first stars and galaxies.
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Modul pro řízení a sběr dat z pyranometru / The module for control and data acquisition of PyranometersHalm, Martin January 2012 (has links)
This work deals with measuring of intensity solar radiation by pyranometer. In theory discusses the principle of solar radiation and its effects on photovoltaic cells. Also describes methods to measure different components of solar radiation. A task work is realize station for long time monitoring of global and diffuse components of solar radiation by pyranometer and measured values evaluace
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Transmissividade atmosférica da irradiação solar global infravermelha, horária e diária, em Botucatu/SP/Brasil /Rossi, Luciano Ronaldo January 2020 (has links)
Orientador: João Francisco Escobedo / Resumo: O trabalho apresenta uma análise estatística e climática das irradiações global (HG) e global infravermelha (HGNIR) e das frações global total (Kt = HG/H0) e global infravermelha (KtNIR = HGNIR/H0NIR), transmitidas na atmosfera no período de 2001 a 2006 em Botucatu/SP/Brasil. Os valores das frações médias Kt e KtNIR (horária e diária) calculadas estatisticamente foram: Kth = 50,0%, KtNIRh = 42,0%, e Ktd = 56,0%, KtNIRd = 48,0%, respectivamente. O estudo mostra ainda a obtenção e a validação da equação de estimativa para KtNIR em função de Kt obtidas por regressão linear (y = ax), onde KtNIRh = 0,850Kth e KtNIRd = 0,855Ktd apresentaram elevados coeficientes de determinação: R2 = 0,981 e R2 = 0,987, respectivamente. Os valores horários obtidos na validação (ano típico e atípico) foram (rMBE)h = 1,0% e 0,2%, (rRMSE)h = 6,3% e 5,3%; dh = 0,994 e 0,996 respectivamente, enquanto que os valores diários foram (rMBE)d = 0,9% e 0,05%; (rRMSE)d = 3,4% e 2,6%; dd = 0,995 e 0,998. Os resultados mostram que as equações podem ser utilizadas com precisão e exatidão nas estimativas de KtNIR. A análise sazonal mostrou que a equação KtNIRh = 0,850Kth anual superestima KtNIRh no verão e primavera em 2,8% e 1,0%, e subestima-o no outono e inverno em 1,0% e 2,6%, respectivamente. Similarmente, KtNIRd = 0,855Ktd anual superestima KtNIRd no verão e primavera em 2,8% e 1,3% e subestima-o no outono e inverno em 1,0% e 2,1%, respectivamente. A análise por cobertura de céu mostrou que: o valor KtNIRh an... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This paper describes the statistical and climatic analysis of global (HG) and infrared global (HGNIR) irradiations, and total global (Kt = HG/H0) and infrared global (KtNIR = HGNIR/H0NIR) fractions, transmitted in the atmosphere from 2001 to 2006 in Botucatu/SP/Brazil: Values of mean fractions Kt and KtNIR (hourly and daily) calculated statistically were as follows: Kth = 50,0%, Kth NIR = 42,0%, and Ktd = 56,0%, KtNIR d = 48,0%, respectively. The study also presents obtaining and validation of the estimate equation for KtNIR as a function of Kt. The equations obtained by linear regression (y = ax) KtNIR h = 0,850Kth and KtNIR d = 0,855Ktd had high determination coefficient: R2 = 0,981 and 0,987 respectively. Hourly values based on validation (typical and atypical years) were as follows: (rMBE) h = 1,0% and 0,2%, (rMSE) h = 6,3% and 5,3%; d h = 0,994 and 0,996, respectively. Daily values were as follows: (rMBE) d = 0,9% and 0,05%; (rMSE) d = 3,4% and 2,6%; d d = 0,995 and 0,998. The results show that the equations can be used precisely and accurately for KtNIR estimates. Seasonal analysis showed that the annual KtNIR h = 0,850Kth equation overestimates KtNIR h in the summer and spring by 2,8% and 1,0% and underestimates it in the autumn and winter by 1,0% and 2,6%, respectively. Similarly, KtNIR d = 0,855Ktd equation anual overestimates KtNIR d in the summer and spring by 2,8% e 1,3% and underestimates it in the autumn and winter by 1,0% e 2,1%, respectively. Considering sky c... (Complete abstract click electronic access below) / Mestre
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Insolation, Precipitation, and Moisture Maps for a Virginia Geographic Information SystemKlopfer, Scott D. 18 August 1997 (has links)
Climate information is valuable in understanding the ecology of systems affecting wildlife. This information is often unavailable at the landscape scale. This study evaluated the applicability of several climate factor estimates at the landscape-scale, and illustrated the usefulness of estimated climate factors in ecological investigations.
Climate variables estimated for each month of the year were solar radiation, temperature, precipitation, and potential evapotranspiration. Map layers for combined temperature and precipitation, and a moisture index were also created.
Accuracy of the estimates for temperature and precipitation for each 300 m x 300 m pixel were quantitatively assessed. The methods used estimated mean monthly temperature within 1 degree C. Precipitation estimates were within 9 mm of actual recorded value. The estimates for monthly solar radiation were qualitatively assessed, and provided a reasonable relative index to actual solar radiation. Estimates of potential evapotranspiration were determined to be reasonably accurate.
Landscape-scale estimated climate factors were used in 2 case studies. The first used logistic regression to examine the importance of climate factors to the observed distribution of 21 select forest cover-types in Virginia.The second compared the observed climate characteristics for the distributions of 3 species of terrestrial salamanders in Virginia. Winter temperature was the most important climate variable in determining forest cover-type distribution. Several differences in the climate characteristics of the 3 salamander distributions were observed and discussed. The conclusions of this study were that landscape-scale climate factors can be accurately estimated, and the estimates may be helpful in ecological investigations. / Master of Science
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Advanced Ray Tracing Techniques for Simulation of Thermal Radiation in FluidsSemlitsch, Bernhard January 2010 (has links)
For modeling thermal heat transfer, not only the effects of convection and conduction are relevant, but also thermal and visible radiation. Radiation is especially important for setups with large temperature differences, as well as for interaction with external light sources.Common computational fluid dynamic models usually treat radiation transport as a minor effect, that can be handled by simplified algorithms. All these normal models, e.g. surface to surface model, discrete transfer model, P_N method, discrete ordinates model, exhibit disadvantages in the computing performance and the physical modeling. Hence, there are many technical applications, where the fluid simulation are limited both in accuracy and calculation time by the available radiation model. As exemplary cases combustion chambers, smoke and soot creation, solar power generation, UV water disinfection, condensation in car headlights, fusion and fission reactor chambers, electric arc movement, as well as low-emissivity glass windows can be named. In the fields investigating radiation as main effect, e.g. cinematic 3d animation or illumination simulation for lamps and workspaces, the mentioned methods are not in use anymore as ray tracing is the first choice. In this work, the existing methods for ray tracing were adapted and implemented with the goal to interact with fluid flow simulations and replace existing radiation modeling. This can be regarded as innovative, interdisciplinary method for the interaction of fluids and solids with radiation, incorporating physical effects that could not be included in previous simulations. While in usual light calculations, the geometry exists solely in the form of surfaces and their triangulation, fluid flow requires volumetric calculation grids. Hence, methods are implemented that actually use the volumetric grid, and incorporate volumetric effects with little additional effort. Spectral volumetric path tracing with Monte Carlo integrated, importance sampled emission was hence the method of choice for this work. The implemented ray tracer is able to emit radiation from point sources, geometric surfaces, as well as from volumetric sources. Spectral dependence of material values is treated using radiation bands with hardly no increase of calculation time, whereas in all other models, the calculation time scales linearly with the amount of bands. Direct, diffuse and mixed surface reflection is modeled. The volumetric refraction index is implemented, so refraction is modeled, even including partial and total reflexion. The focusing of lenses or mirror systems can hence be simulated satisfactory, which cannot be treated sufficiently by any other radiation model. Surface and volumetric absorption are implemented, as well as surface and volumetric scattering effects. The radiation emission can be caused by a temperature field at surfaces and volumes. These fields are imported from software calculating the fluid and the thermal system. Ray tracing results in volumetric and surface heat sources that can be returned to the original code, and their effect further calculations. This coupling was implemented and tested with the commercial computational fluid dynamics code Fluent, using its plug-in interface. As most of Fluent's radiation models are only performed after a fixed number of implicit flow and turbulence iterations, no further disadvantages or limitations occur, that are not as well existing for the existing radiation simulations. A fully implicit treatment of radiation is unlikely to be performed, as stability is already sufficient for most applications. Of course, systems containing only heat sources caused by light and no secondary heat radiation can be treated by the implemented ray tracer with high performance. The implemented ray tracer is validated with analytically solved systems, and compared to quantitative simulation results of other simulation methods. Also, the scattering effects are validated against experimental and simulation results from literature. The observed calculation performance is similar or faster then for standard models with geometries of approximately 150000 volume elements, while the modeling is done more accurately. For larger models, even larger advantages can be expected.
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