Análise Energética da cultura do crambe (Crambe abyssinica hochst) produzida em plantio direto

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Demanda energética em diferentes sistemas de preparo periódico do solo antes e depois da subsolagem

Both the inadequate use and the ignorance of the different soil tillage implements available in the home market has become one of the leading motives of failures, related to soil and water conservation. The periodical tillage is traditionally utilized after subsoiling for soil clod breaking, leveling and residue incorporation. This work aimed to evaluate the energy requirement for different periodical soil tillage systems performed before and after subsoiling in a soil classified as Distroferric Red Nitosol. The periodic tillage systems were: disk plowing; disk plowing plus one leveling harrowing; disk harrow; disk harrow plus leveling harrowing stirring. The experimental design was a 5x2 factorial scheme with 5 completely randomized blocks. The results show that the periodic soil preparation systems based on disks have better energy efficiency when performed before the operation of subsoiling. The system of soil preparation with harrowing obtained the lower energy demand, in relation to other periodic soil preparation systems, when done after subsoiling.

Avaliação do desempenho de um sistema de secagem projetado para os pequenos produtores rurais

O presente trabalho foi realizado na Fazenda Experimental Lageado, da Universidade Estadual Paulista em Botucatu, SP, e objetivou-se analisar o desempenho de um silo secador alambrado com ar à temperatura ambiente, de projeto simples, com possibilidades de atender às necessidades de pequenos cafeicultores. Para a avaliação do desempenho da secagem, foram realizadas medições do teor de água do café, temperaturas da massa de grãos, do ar de exaustão, do ar de secagem e do ar ambiente, umidade relativa ambiente, velocidade do ar de secagem e o tempo total de secagem. Para avaliar a qualidade do produto seco, foi feito o teste de bebida. Paralelamente, realizou-se a secagem em terreiro para se formar a testemunha. Os resultados observados permitiram concluir que o silo secador alambrado apresentou uma boa eficiência energética, proporcionando um produto seco com o mesmo padrão de qualidade do café seco em terreiro.

Controle inteligente de pressão para uma rede sem reservatório de abastecimento urbano de água

The sanitation companies from Brazil has a great challenge for the XXI century: seek to mitigate the rate of physical waste (water, chemicals and electricity) and financial waste caused by inefficient operating systems drinking water supply, considering that currently we already face, in some cases, the scarcity of water resources. The supply systems are increasingly complex as they seek to minimize waste and at the same time better serve the growing number of users. However, this technological change is to reduce the complexity of the challenges posed by the need to include users with higher quality and efficiency in services. A major challenge for companies of water supplies is to provide a good quality service contemplating reducing expenditure on electricity. In this situation we developed a research by a method that seeks to control the pressure of the distribution systems that do not have the tank in your setup and the water comes out of the well directly to the distribution system. The method of pressure control (intelligent control) uses fuzzy logic to eliminate the waste of electricity and the leaks from the production of pumps that inject directly into the distribution system, which causes waste of energy when the consumption of households is reduced causing the saturation of the distribution system. This study was conducted at Green Club II condominium, located in the city of Parnamirim, state of Rio Grande do Norte, in order to study the pressure behavior of the output of the pump that injects water directly into the distribution system. The study was only possible because of the need we had to find a solution to some leaks in the existing distribution system and the extensions of the respective condominium residences, which sparked interest in developing a job in order to carry out the experiments contained in this research

Roteamento em Redes de Sensores Sem Fios Com Base Em Aprendizagem Por Reforço

The use of wireless sensor and actuator networks in industry has been increasing past few years, bringing multiple benefits compared to wired systems, like network flexibility and manageability. Such networks consists of a possibly large number of small and autonomous sensor and actuator devices with wireless communication capabilities. The data collected by sensors are sent directly or through intermediary nodes along the network to a base station called sink node. The data routing in this environment is an essential matter since it is strictly bounded to the energy efficiency, thus the network lifetime. This work investigates the application of a routing technique based on Reinforcement Learning s Q-Learning algorithm to a wireless sensor network by using an NS-2 simulated environment. Several metrics like energy consumption, data packet delivery rates and delays are used to validate de proposal comparing it with another solutions existing in the literature

Desempenho de um painel fotovoltaico de baixa tensão, acoplado ao protótipo de um conversor dc/dc topologia Booster

Low voltage solar panels increase the reliability of solar panels due to reduction of in series associations the configurations of photovoltaic cells. The low voltage generation requires DCDC converters devices with high efficiency, enabling raise and regulate the output voltage. This study analyzes the performance of a photovoltaic panel of Solarex, MSX model 77, configured to generate an open circuit voltage of 10.5 V, with load voltage of 8.5 V, with short circuit current of 9 A and a power of 77 W. The solar panel was assembled in the isolated photovoltaic system configuration, with and without energy storage as an interface with a DCDC converter, Booster topology. The converter was designed and fabricated using SMD (Surface Mounted Devices) technology IC (integrated circuit) that regulates its output voltage at 14.2 V, with an efficiency of 87% and providing the load a maximum power of 20.88 W. The system was installed and instrumented for measurement and acquisition of the following data: luminosities, average global radiation (data of INPE Instituto Nacional de Pesquisas Espaciais), solar panel and environment temperatures, solar panel and DC-DC converter output voltages, panel, inverter, and battery charge output currents. The photovoltaic system was initially tested in the laboratory (simulating its functioning in ideal conditions of operation) and then subjected to testing in real field conditions. The panel inclination angle was set at 5.5°, consistent with the latitude of Natal city. Factors such as climatic conditions (simultaneous variations of temperature, solar luminosities and ra diation on the panel), values of load resistance, lower limit of the maximum power required by the load (20.88 W) were predominant factors that panel does not operate with energy efficiency levels greater than 5 to 6%. The average converter efficiency designed in the field test reached 95%

Análise comparativa entre propriedades mecânicas, termofísicas e geométricas de tijolos produzidos pelos fornos caieira e abóbada

In the State of Rio Grande do Norte potteries are distributed in several counties in the four meso, which are: West Potiguar, Center Potiguar, Agreste Potiguar and East Portiguar. The ceramics, mostly, are responsible for products used in construction as bricks, tiles and white brick and wood used as fuel. This paper had a primary focus in the region of Seridó. The furnaces in this region, used to manufacture bricks are configured Caieira and Valt, in most of them using principles rustic, usually operated in an empirical way, using principles of control rather primitive, predominantly visual control. The focus of this study was to analyze the differences in the thermophysical, mechanical and geometric characteristics of bricks produced by Caieira and vault furnaces, using the NBR 15720 and the evaluation of energy efficiency in both furnaces. Thermophysical characteristics were analyzed through tests to determine the water absorption obtained from the difference between dry mass and wet mass of the sample and analysis of the thermal gradient, the mechanical characteristics from determination of the compressive strength of ceramic brick popularly known as bricks and also analyzed the geometrical characteristics of the bricks in order to verify the homogeneity of manufacturing. The tests showed that the energy difference of the two furnaces is not considered responsible for a significant difference in the properties of the products

Balanço energético de um forno túnel de cerâmica estrutural convertido de lenha para gás natural

In energy systems, the balance of entrances, exits and losses are fundamental to rationalize the energy consumption, independently of the source (sun, natural gas, wind, water, firewood or oil). This estimate is important so much in the phase of project of the facilities, as in the exploration or operation. In the project phase it indicates the energy needs of the process and the contribution of the energy in the cost of the product and the capacity of storage of the fuel and in the operation phase it allows to evaluate the use of the energy in the process of it burns, showing the weak points that should suffer intervention to improve the efficiency. With this tool, it can be implemented routines of calculation of thermal balances in ovens of it burns of structural ceramic, in way to generate an optimized mathematical model for application in the current and promising structural ceramic brazilian industry. The ceramic oven in study is located in the metropolitan area of Natal (Rio Grande do Norte) and it is a continuous oven of the type wagons tunnel, converted of firewood for natural gas and it produces blocks of red ceramic. The energy balance was applied in the oven tunnel before and after the conversion and made the comparisons of the energy efficiencies (it burns to the firewood and it burns to natural gas), what showed that the gaseous fuel is more efficient when we burn structural ceramic in ovens tunnels. When we burn natural gas, the requested energy is smaller and better used. Tests were accomplished in the burned product that showed the best quality of the burned brick with natural gas. That quality improvement makes possible to accomplish new interventions for the most rational use of the energy in the oven tunnel of the Ceramic in study and in the industries of structural ceramic of the whole Brazil, that need control tools of burning and of quality

Electrically, Chemically, and Photonically Powered Torsional and Tensile Actuation of Hybrid Carbon Nanotube Yarn Muscles

Artificial muscles are of practical interest, but few types have been commercially exploited. Typical problems include slow response, low strain and force generation, short cycle life, use of electrolytes, and low energy efficiency. We have designed guest-filled, twist-spun carbon nanotube yarns as electrolyte-free muscles that provide fast, high-force, large-stroke torsional and tensile actuation. More than a million torsional and tensile actuation cycles are demonstrated, wherein a muscle spins a rotor at an average 11,500 revolutions/minute or delivers 3% tensile contraction at 1200 cycles/minute. Electrical, chemical, or photonic excitation of hybrid yarns changes guest dimensions and generates torsional rotation and contraction of the yarn host. Demonstrations include torsional motors, contractile muscles, and sensors that capture the energy of the sensing process to mechanically actuate.

Análise energética de sistemas de produção de etanol de mandioca (Manihot esculenta Crantz)

This work aimed to analyze the energetic consumption of the etanol production system, using the cassava as carbohidrates source. The researches were carried out from the field in the mid region of Paranapanema river, São Paulo state, during the period January to December, 2007. The energy consumption referring to the phases of crop production and industrial processing were appraised. It was verified that the total energetic cost of the crop production corresponded to 9,528.33 MJ ha(-1), and the most onerous item was the inputs (35.72%). In the industrial step, the energetic consumption was equivalent to 2,208.28 MJ t(-1). The operations of hydrolysis/saccharification/treatment of the juice represented 56.72% of the total energetic expenditure. The cassava crop presented an energetic cost of 1.54 MJ L-1 in relation to the etanol produced in the main agronomic operations crop production, and 11.76 MJ L-1 in the industrial processing. The energy efficiency observed in the cultivation and industrialization of the cassava was of 1.76.

Avaliação energética da produção de etanol utilizando como matéria-prima a cana-de-açúcar

This research analyzed the energetic consumption of the etanol, using as raw-material sugar cane. The searches were carried out from the field in the Midle Paranapanema River Region, São Paulo state, in the period from January to December 2007. The referring energy consumption from the crop production phase and industrial processing were evaluated. It was verified that the total energetic cost of the crop production corresponded to 14370.9MJ ha(-1), and the most onerous item was the inputs (50.4%). In the industrial step, the energetic consumption was equivalent to 1,641.56MJ t(-1), The 'hydrolysis, saccharification and broth treatment operations' represented 71.72% of the total energetic expenditure. It was also observed an energetic cost of 2.0MJ L(-1) in relation to the etanol produced in the main crop production operations, and 19.4MJ L(-1) in the industrial processing. The energy efficiency observed in the crop production and industrialization were of 1.1.

Electricity, hot water and cold water production from biomass. Energetic and economical analysis of the compact system of cogeneration run with woodgas from a small downdraft gasifier

Wood gasification technologies to convert the biomass into fuel gas stand out. on the other hand, producing electrical energy from stationary engine is widely spread, and its application in rural communities where the electrical network doesn't exist is very required. The recovery of exhaust gases (engine) is a possibility that makes the system attractive when compared with the same components used to obtain individual heat such as electric power. This paper presents an energetic alternative to adapt a fixed bed gasifier with a compact cogeneration system in order to cover electrical and thermal demands in a rural area and showing an energy solution for small social communities using renewable fuels. Therefore, an energetic and economical analysis from a cogeneration system producing electric energy, hot and cold water, using wooden gas as fuel from a small-sized gasifier was calculated. The energy balance that includes the energy efficiency (electric generation as well as hot and cold water system; performance coefficient and the heat exchanger, among other items), was calculated. Considering the annual interest rates and the amortization periods, the costs of production of electrical energy, hot and cold water were calculated, taking into account the investment, the operation and the maintenance cost of the equipments. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved.

Analysis of the performance of an extraction-condensation steam turbine on a cogeneration system of a Brazilian sugar-alcohol factory

In this work a detailed thermodynamic analysis for an extraction-condensation steam turbine capable to drive a 40 MVA electricity generator in a sugar-alcohol factory was carried out. The use of this turbine in the cogeneration system showed that its efficiency contributed to increase the power generation, although the condensation reduces the overall efficiency of the plant. Sensibility analyses were performed to evaluate the behavior of the overall energy efficiency of a plant with the extraction-condensation turbine in function of the boiler efficiency, the specific consumption of steam in the processes and the condensation rate in the turbine. It was observed that the plant efficiency is very sensible to the condensation rate variation and it increases when there is an increase in the demand of steam for processes.

Estudo geofísico de vazamento controlado de álcool combustível em escala laboratorial

O etanol é utilizado de forma extensiva como combustível para veículos automotores no Brasil, devido tanto a características como ao clima favorável ao cultivo de cana-de-açúcar em uma cadeia produtiva bastante desenvolvida quanto à eficiência energética e ao teor quase inexistente de poluentes emitidos emsua combustão. A ampla rede de distribuição para atendimento ao consumidor final representa um risco constante de vazamentos e contaminação de rios, solo e água subterrânea. Este trabalho discute os resultados do monitoramento geofísico num experimento em escala de laboratório, resultante do vazamento controlado de etanol em sedimentos parcialmente saturados em água. A extensa aplicação de métodos elétricos em estudos ambientais e alterações significativas em termos de resistividade elétrica, provocada no ambiente geológico pela presença de compostos exógenos, justifica a seleção do método. Houve um aumento dos valores no início do experimento até o máximo em torno de 52h, seguido por queda acentuada até 342h e sucedido por crescimento lento e constante dos valores até 2.742h, quando comparados a valores prévios sem adição de etanol. Os dados sugerem uma relação temporal entre variações de resistividade elétrica e o comportamento geoquímico do etanolno ambiente geológico.

Perfil nutricional e cardiovascular de ratos normotensos e hipertensos sob dieta hiperlipídica

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)