Viabilidade de utilização de um compósito de matriz cerâmica com cargas recicláveis na fabricação de equipamentos solares

Composite materials can be defined as materials formed from two or more constituents with different compositions, structures and properties, which are separated by an interface. The main objective in producing composites is to combine different materials to produce a single device with superior properties to the component unit. The present study used a composite consisting of plaster, cement, EPS, tire, PET and water to build prototype solar attempt to reduce the manufacturing cost of such equipment. It was built two box type solar cookers, a cooler to be cooled by solar energy, a solar dryer and a solar cooker concentration. For these prototypes were discussed the processes of construction and assembly, determination of thermal and mechanical properties, and raising the performance of such solar systems. Were also determined the proportions of the constituents of the composite materials according to specific performance of each prototype designed. This compound proved to be feasible for the manufacture of such equipment, low cost and easy manufacturing and assembly processes

Análise comparativa da viabilidade econômica da utilização de coletores solar para aquecimento de água

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Estudo comparativo de coletores solares sem cobertura utilizados para aquecimento de piscinas

Pós-graduação em Engenharia Mecânica - FEB

Filtros UV na água de abastecimento público na região da bacia hidrográfica tietê-jacaré: desenvolvimento de método, estudo de ocorrência e concentrações ambientais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Levantamento bibliográfico sobre o método SODIS de desinformação solar da água

Frente ao desafio de prover água de melhor qualidade para o uso humano a um custo acessível e de simples execução, muitos métodos tem sido desenvolvidos e estudados. Uma metodologia que tem se destacado atualmente, é o método SODIS, sigla em inglês que significa, desinfecção da água por meio da luz solar. Essa metodologia tem como princípio a inativação de uma variada gama de microrganismos patogênicos a partir da ação dos raios solares. Essa metodologia consiste em submeter garrafas de água a um banho de luz solar por algumas horas. Para a realização do método SODIS pode-se utilizar garrafas PET (politereftalato de etileno), sendo que sua execução é simples e rápida além de possuir mínimos riscos envolvidos. A fim de comprovar a eficácia desse método, muitos estudos tem investigado os mecanismos e fatores importantes envolvidos no processo de inativação. Da compreensão desses mecanismos e fatores críticos, preconizou-se ações que visam garantir e maximizar a eficiência do método em variadas situações e condições climáticas sem que o método se torne complexo ou oneroso. O método SODIS se mostrou eficaz na inativação de várias espécies de fungos, vírus, bactérias e até protozoários. Estudos de campo revelaram a sua eficácia prática, ocasionando uma diminuição expressiva nas ocorrências referentes a quadros de diarréia e diarréia severa nas populações estudadas

Estudo do potencial de associações de ZnO com os produtos naturais ácido cafeico e ferúlico como filtros solares híbridos: [recurso eletrônico]

In this work were studied associations of ZnO with the natural products caffeic and feluric acids. Two preparation methods were used, that is, the sol-gel and a reflux procedure. In the sol-gel method, ZnO is produced by the basics hydrolysis of precursors in the presence of the organic filters (caffeic and feluric acids), which results in 30 nm (or less) ZnO particles with the organic filters (in dissociated form) bonded to the surface of ZnO. In the reflux method, a dispersion of ZnO in a water/ethanol mixture was kept under reflux (50oC/4h) in the presence of the organic acids. The ZnO particles used in the reflux method have a higher diameter than sol-gel ZnO particles, but the prepared associated product ZnO/Organic acids were similar. Despite of the difference in relation to crystallinity between the products, the preparation methods resulted in analogous associations with respect to the interaction of the organic filters with the ZnO surface. The caffeic/ZnO associations presented low photostability, which lead to the degradation of the organic filter. The other associations (feluric acid/ZnO) presented satisfactory results. The FT-IR spectroscopy confirmed the formation of the association, and the nature of the bond formed compared with the Zn-O bond in Zn2+/Felutic acid complexes. The isolated organic and inorganic filters, along with the associations were analyzed by diffuse reflectance spectroscopy and Uv-vis spectroscopy. The absorption edges and the critical wavelengths were analyzed and the effects of Zn-O bonds in feluric acid/ZnO associations described as a function of the relative position of the π/π* system of the organic filter. Finally the performance of the hybrid filters were investigated in terms of the absorption of UVA and UVB radiations, with the UVA/UVB ratio, an efficiency parameter largely used in the description of solar filters, sunscreen and suncare products

Análise técnica e econômica da utilização da energia solar e eólica em uma propriedade rural para geração de eletricidade, bombeamento e aquecimento de água

This paper is about a case study of using solar energy and wind energy in a farm. For this purpose were collected from the property, such as water consumption and amount of residents. So, we estimate how many conventional panels or PET bottle panels and boiler needed to supply the farm with warm water. It also calculates the amount of photovoltaic panels and the main accessories for converting solar energy into electrical energy. For the pumping of water using photovoltaic panels is dismissed and dimensioned to be a watermill

Análise numérica de uma geometria de coletor solar para sistemas de aquecimento de água

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Sistema fotovoltaico monocristalino para bombeamento de água

Since ancient times, it has been a huge challenge to all people around the world to manage to get their fresh water, keeping it clean and providing it to every human being, so that it can be used for their daily needs. This is especially true for small properties in the countryside and in isolated areas with low demographic density. Pumping the water in those regions is a solution that rationalizes its use in domestic chores, in animal rearing and in the irrigation systems of cultivated areas. Making feasible local, renewable and non-polluted energetic alternatives is the aim for those areas that are usually far away from the public electric network. Using photovoltaic solar energy is the alternative now proposed. For this objective was built a system with two monocrystalline panels, one pump, two water tanks, two level sensors and a solenoid valve to pump water, using a pump powered an array of monocrystalline solar panels. The main goal was to compare their rate of water flow and their energy consumption. The use of one data acquisition equipment allowed collecting meteorological, electrical and hydraulic values, and also serving for the control and activation of the pumping system. During four months in a row as from April 2009, arrangements with one or two panels were tested. Mathematics correlations and adjustment lines were used to interpret the behavior of obtained dataset. During the analyzed period the system followed the linear equations with great accuracy. The daily average amount of water pumped by the several tested arrays stayed between 1,100 and 2,500 liters, and that is enough to supply a small rural property. The pumping system with two panels effectively showed the major amount of water, but a system with one panel can be an economical solution until 1,500 liters on day. It did not characterize a direct relationship between power or quantity of photovoltaic panels and daily outflow of water pumping.

Classificação de água de coco processada e natural por meio de HCA, PCA e teores de íons metálicos determinados por ICP OES

Inductively Coupled Plasma Optical Emission Spectrometry was used to determine Ca, Mg, Mn, Fe, Zn and Cu in samples of processed and natural coconut water. The sample preparation consisted in a filtration step followed by a dilution. The analysis was made employing optimized instrumental parameters and the results were evaluated using methods of Pattern Recognition. The data showed common concentration values for the analytes present in processed and natural samples. Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) indicated that the samples of different kinds were statistically different when the concentrations of all the analytes were considered simultaneously.

Sulfetos volatilizáveis por acidificação e metais extraídos simultaneamente na avaliação de sedimentos de água doce

This paper discusses the historical and methodological fundaments of the dynamics and quantification of acid volatile sulfides (AVS) and simultaneously extracted metals (SEM) in aquatic sediments. It also discusses the SEM/AVS relationship, which involves several controversial aspects such as sulfide stability, sulfide-organic matter interaction, and the inability to predict the toxicity of organic compounds in the environment. This relationship is an important tool for the inference of metal bioavailability. The use of ecotoxicological tests with target organisms regulated by international standards is also a relevant aspect.

Efeitos da cobertura do solo com filme de polietileno azul no consumo de água da cultura da alface cultivada em estufa

The covering of the soil is an agricultural practice that intends to control the harmful herbs, to reduce the losses of water by evaporation of the soil, and to facilitate the harvest and the commercialization, once the product is cleaner and healthier. However, when the soil is covered important microclimatic parameters are also altered, and consequently the germination of seeds, the growth of roots, the absorption of water and nutrients, the metabolic activity of the plants and the carbohydrates storage. The current trial intended to evaluate the effect of soil covering with blue colored film on consumptive water-use in a lettuce crop (Lactuca sativa, L.). The experiment was carried out in a plastic greenhouse in Araras - São Paulo State, Brazil from March 3rd, 2001 to May 5th, 2001. The consumptive water-use was measured through two weighing lysimeter installed inside the greenhouse. Crop spacing was 0.25 m x 0.25 m and the color of the film above soil was blue. Leaf area index (IAF), was measured six times (7; 14; 21; 28; 35; 40 days after transplant) and the water-use efficiency (EU) was measured at the end. The experimental design was subdivided portions with two treatments, bare soil and covered soil. The average consumptive water-use was 4.17 mm day-1 to the bare soil treatment and 3.11 mm day-1 to the covered soil treatment. The final leaf area index was 25.23 to the bare soil treatment and 24.39 to the covered soil treatment, and there was no statistical difference between then.

Teores de nutrientes na alface irrigada com água residuária aplicada por sistemas de irrigação

A trial was carried out to evaluate the chemical composition in the aerial part of lettuce, cv. 'Elisa', irrigated with wastewater treated with constructed wetland and source deposit water, grown on a Rhodic Hapludox Soil, using the irrigation systems sprinkle, subsurface drip and surface drip irrigation. The experiment was carried out from August 17th to October 3rd of 2001 and the chemical analyses of the lettuce were accomplished to 47 days after transplanting of the seedling. The aerial part of the lettuce was analyzed as for the levels of total nitrogen, nitrate, phosphorus, potassium, calcium, magnesium, sulfur, iron, manganese, copper, zinc, sodium, boron, cobalt and molybdenum. The sodium and the sulfur presented higher levels than the maximum suitable in the aerial part of the lettuce and the smallest level of magnesium, while other chemical elements analyzed were normal and appropriate considering the standard for well-nourished plants, not being influenced by the water type. The sodium was the chemical element that presented the highest levels in the aerial part of the lettuce in the treatments irrigated with wastewater, presenting significant difference in relationship to the treatments irrigated with source deposit water in the three irrigation systems. The use of the different irrigation systems by the application of wastewater treated with constructed wetland did not interfere in the levels of nutrients in the aerial part of the lettuce.

Influência da temperatura do ar de secagem no calor latente de vaporização de água em feijão macassar (Vigna unguiculata (L.) Walp.), variedade sempre-verde

In order to determine the energy needed to artificially dry an agricultural product the latent heat of vaporization of moisture in the product, H, must be known. Generally, the expressions for H reported in the literature are of the form H = h(T)f(M), where h(T) is the latent heat of vaporization of free water, and f(M) is a function of the equilibrium moisture content, M, which is a simplification. In this article, a more general expression for the latent heat of vaporization, namely H = g(M,T), is used to determine H for cowpea, always-green variety. For this purpose, a computer program was developed which automatically fits about 500 functions, with one or two independent variables, imbedded in its library to experimental data. The program uses nonlinear regression, and classifies the best functions according to the least reduced chi-squared. A set of executed statistical tests shows that the generalized expression for H used in this work produces better results of H for cowpea than other equations found in literature.

Adequação de engates rápidos de aspersores como conectores de mangueira para distribuição de água em sulcos de irrigação

As a way to reduce water losses in furrow irrigation systems, used in fresh market tomato production, farmers are improperly distributing water into the field using plastic hose. The objective of this work was to study the suitability of using quick coupler sprinkler as hose connectors for water distribution in tomato plantation. The first step of the study was to assess the current hose field operation for tomato growers. Subsequently, four models of quick couplers sprinklers available in the market were tested in laboratory to determine the coefficient of resistance, the equivalent tube length, the head loss curve and the linking efficiency. As result, a structural design for hose connectors was presented using the model of coupling with the best hydraulic performance. Additionally, some technical recommendations on its use in irrigation water distribution are highlighted. Despite the requirement for additional field trials, the proposed system has potential to optimize the water use efficiency, to improve workers ergonomic conditions, and ensure good profitability to the producer.