Desempenho da mamoneira IAC 2028 em função do espaçamento entre fileiras e população de plantas na safrinha

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

Avaliação de desempenho da codificação wavelet em canais seletivos em frequência

Wavelet coding has emerged as an alternative coding technique to minimize the fading effects of wireless channels. This work evaluates the performance of wavelet coding, in terms of bit error probability, over time-varying, frequency-selective multipath Rayleigh fading channels. The adopted propagation model follows the COST207 norm, main international standards reference for GSM, UMTS, and EDGE applications. The results show the wavelet coding s efficiency against the inter symbolic interference which characterizes these communication scenarios. This robustness of the presented technique enables its usage in different environments, bringing it one step closer to be applied in practical wireless communication systems

Caracterização de escovas de grafite e avaliação do seu desempenho em função da microestrutura

The electric can be converted into thermal, luminous, electromagnetic, and also in mechanical energy. In this context the electric engines plays a fundamental role, specially that they work very below of its nominal capacity, with consequent decrease load density. In industrial environment, these characteristics of work of DC engines had also generated an extreme consumption of coal brushs and attack in the commutator reducing the useful life of the engine and increasing maintenance demand and cost. The general objective of the present work is to study the influence of the granulometry of the coal brush used in DC engines with the resistance to the consumption of the same ones, as well as in the performance presented by the commutator of the engine. Additionally, determining the measurable and not measurable profits when the brush used is adjusted to the application. The brushes had been produced by an industry of the sector and tested in industrial environment to evaluate their performance and consumption. Preliminary results evidence a substantial improvement in the performance of these brushes in function of its microstructure and the application in which it is used

Projeto, construção e análise de desempenho de um forno solar alternativo tipo caixa a baixo custo

An alternative box-type solar oven constructed from the scrap iron of a gas conventional cook is presented, which functions principles are the effect greenhouse and the concentration. The oven of the conventional cook is the baking enclosure where the absorber (pot) of the solar oven is located, being re-covered for a glass blade for the generation of the greenhouse effect isolated lateral and having deep its and for a composite the plaster base and EPS. Segments of plain mirrors had been placed in the laterals of the oven for the concentration of the radiation and a reflecting parabola was introduced in the baking enclosure for the exploitation of the incident reflected radiation in the interior of the oven. The oven is mobile to allow one better aiming of exactly in relation to the apparent movement of the sun. The thermal economic and of materials viabilities of the stove in study will be demonstrate The average internal temperature of the absorber was around 150°C and the internal temperature around 120°C. Will demonstrate that its low cost and good thermal performance represents basic characteristics for the viability of large use of such archetype, mainly for cooking the decreases and averages temperatures. One will reveal that the archetype in study is competitive with the box-type solar cooker conceived in the whole world

Construção e análise de desempenho de um forno/fogão solar tipo caixa construído a partir de uma sucata de pneu

An alternative box-type solar cooker built starting from the scrap of a tire and a scrap of old office chair is presented, which principles functions are the effect greenhouse and the concentration. The tire served as structure for making of is the baking enclosure where the absorber (roasting pan 20x30cm) of the solar is located, being re-covered for a glass blade for the generation of the greenhouse effect isolated lateral and having deep its and for a composite the plaster base and EPS. Segments of plain mirrors had been placed in the laterals of the oven/cook for the concentration of the radiation and a reflecting parable was introduced in the baking enclosure for the exploitation of the incident reflected radiation inside of the oven/cook. The oven/cook is mobile to allow one better aiming of exactly in relation to the apparent movement of the sun. The thermal economic and of materials viabilities of the stove/cook in study will be demonstrate. The average internal temperature of the absorber was around 152,3°C and the internal temperature around 110°C. Will demonstrate that toits low cost and good thermal performance, represents basic characteristics for the viability of large use of such archetype, mainly for cooking the decreases and averages temperatures. One will reveal that the archetype in study is competitive with the box-type solar cooker conceived in the whole world

Desempenho de três variedades de soja na região dos tabuleiros costeiros no estado Alagoas

The objective of this work, the performance of three varieties of soybean on "Tabuleiros Costeiros" State of Alagoas. The installation of the experiment occurred on March 20, 2006, picking up the parcels on 26 August 2006. The experimental design was a randomized blocks with seven repetitions. The experimental plots consisted of ten rows of 4.0 m in length, spaced 0.50 m. In ten plants per plot were marked certain height of the plant in full bloom stage R2 and point of harvest stage R9 considering the distance between the soil surface and apical end of the main stem, the body weight of 100 seeds, grain production and dry weight in (kg ha(-1)) which are calculated from the production harvested per plot. The soybean plants of three varieties showed height below the minimum required for mechanical harvesting. The three varieties yield or more of the traditionally producing. The average of dry matter accumulation obtained show the variety BRS Tracaja as a good option for the production of forage.

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%

Performance comparativa entre R290/R600a (50:50) e R134a para drop-in em refrigerador doméstico

This research this based on the seminar on Use of Natural Fluids in Refrigeration and Air-Conditioning Systems conducted in 2007 in Sao Paulo. The event was inserted in the National Plan for Elimination of CFCs, coordinated by the Ministry of Environment and implemented by the United Nations Development Programme (UNDP). The objective of this research is analyze the performance of the hydrocarbons application as zeotropic mixtures in domestic refrigerator and validate the application of technical standards for pull down and cycling (on-off) tests to the mixture R290/R600a (50:50) in domestic refrigerator. It was first developed an computational analysis of R290/R600a (50:50) compared to R134a and other mass fractions of the hydrocarbons mixtures in the standard ASHRAE refrigeration cycle in order to compare the operational characteristics and thermodynamic properties of fluids based on the software REFPROP 6.0. The characteristics of the Lorenz cycle is presented as an application directed to zeotropic mixtures. Standardized pull down and cycling (on-off) tests were conducted to evaluate the performance of the hydrocarbons mixture R290/R600a (50:50) as a drop-in alternative to R134a in domestic refrigerator of 219 L. The results showed that the use of R290/R600a (50:50) with a charge of refrigerant reduced at 53% compared to R134a presents reduced energy performance than R134a. The COP obtained with hydrocarbon mixture was about 13% lower compared to R134a. Pull down times in the refrigerator compartments for fluids analyzed were quite close, having been found a 4,7% reduction in pull down time for the R290/R600a compared to R134a, in the freezer compartment. The data indicated a higher consumption of electric current from the refrigerator when operating with the R290/R600a. The values were higher than about 3% compared to R134a. The charge of 40 g of R290/R600a proved very low for the equipment analyzed

Desempenho de um veículo flex em bancada dinamométrica de chassi

Flex-fuel vehicles are equipped with Otto Cycle internal combustion engines and have the capability of functioning with more than one type of fuel, mixed at the same tank and burned in the combustion chamber simultaneously. This sort of motorization is a world pattern due to the scarcity of petroleum, the trade of several types of fuels, technology advances and the restriction imposed to gas emissions to the atmosphere. In Brazil, the Flexfuel vehicles are a reality, specially the ones using fuel with 20 to 25% anhydrous alcohol mixed with gasoline and those that use natural gas or original liquid fuel (gasoline or hydrated ethanol). The Brazilian model Fiat Siena, the object of this present scientific investigation, is equipped with a unique electronic central capable of managing the liquid or gaseous fuels. The purpose of this research was to perform a comparative analysis in terms of performance (in terms of both potency and consumption) of a tetra-fuel vehicle - using a chassis dynamometer, operating with different fuels: common gasoline, premium gasoline, Podium gasoline, ethanol or natural gas. It became necessary to develop a bench of tests and trials procedures, as well as to know the functioning of the electronic management of the vehicle under analysis. The experiments were performed at the automotive laboratory in CTGAS-ER (Center of Gas Technologies and Renewable energies) at the light of Brazilian standard ABNT, NBR 7024: Light on-road vehicles - measurement of fuel consumption. The essay results on specific fuel consumption using common gasoline, premium gasoline and Podium gasoline have shown similar results, both for urban and road driving cycles

Análise de desempenho de um fogão solar construído a partir de sucatas de antena de tv

Given the growing environmental crisis caused by degradation, mainly due to the use of polluting energy sources, increasing the growing use of renewable energies worldwide, with emphasis on solar energy, an abundant supply and available to everyone, which can be harnessed in several ways: electricity generation; dehydration of food; heating, disinfection and distillation and cooking. The latter has as its primary feature the viability of clean, renewable energy for society, combating ecological damage caused by large-scale use of firewood for cooking foods, use in tropical countries with high solar radiation, and has funding NGOs throughout the world with the goal of achieving low-income population. The proposed project consists of a solar cooker for concentration, working from the reflection of sunlight by a hub that they converge to a focal point at the bottom of the pot, getting lots of heat. The solar cooker under study consists of two elliptical reflecting parabolas made from the recycling of scrap TV antenna, having 0.29 m² of surface area for each antenna, which were covered by multiple mirrors of 2 mm thick and mounted on a metal structure, with correction for the mobility of the apparent movement of the sun. This structure was built with the recycling of scrap metal, possessing a relatively low cost compared with other solar cookers, around US$ 50.00. This cost becomes negligible, since that will involve a great benefit to not have fuel costs for each meal, unlike the use of gas or firewood for cooking food. The tests show that the cooker has reached the maximum temperature of 740 ° C, for boiling water in an average time of 28 minutes, cooking various types of foods such as potatoes, rice and pasta in an average time of 45 minutes and still going as a solar oven, making pizza baking and meat. These cooking times do not differ much from the cooking times on a gas stove, it becomes the solar cooker as a good consumer acceptance, and furthermore not to deliver the same gases that can poison the food as with the wood stove. Proves the viability of using the stove to cook or bake in two daily meals for a family, still presenting a position to improve his performance with the addition of new materials, equipment and techniques

Análise de desempenho de um refrigerador de pequeno porte com drop in de refrigerantes hidrocarbonetos

From what was stated in the Montreal Protocol, the researchers and refrigeration industry seek substitutes for synthetic refrigerants -chlorofluorocarbons (CFCs) and HCFCs (HCFC) - that contribute to the depletion of the ozone layer. The phase-out of these substances was started using as one of the replacement alternatives the synthetic fluids based on hydro fluorocarbons (HFCs) that have zero potential depletion of the ozone layer. However, contribute to the process of global warming. HFC refrigerants are greenhouse gases and are part of the group of gases whose emissions must be reduced as the Kyoto Protocol says. The hydrocarbons (HC's), for not contribute to the depletion of the ozone layer, because they have very low global warming potential, and are found abundantly in nature, has been presented as an alternative, and therefore, are being used in new home refrigeration equipment in several countries. In Brazil, due to incipient production of domestic refrigerators using HC's, the transition refrigerants remain on the scene for some years. This dissertation deals with an experimental evaluation of the conduct of a drinking fountain designed to work with HFC (R-134a), operating with a mixture of HC's or isobutane (R-600a) without any modification to the system or the lubricating oil. In the refrigeration laboratory of Federal University of Rio Grande do Norte were installed, in a drinking fountain, temperature and pressure sensors at strategic points in the refrigeration cycle, connected to an acquisition system of computerized data, to enable the mapping and thermodynamics analysis of the device operating with R-134a or with a mixture of HC's or with R-600a. The refrigerator-test operating with the natural fluids (mixture of HC's or R-600a) had a coefficient of performance (COP) lower than the R-134a

Desempenho de pontas de pulverização em Brachiaria brizantha cv. MG-4 para controle de ninfas de cigarrinhas das pastagens

O trabalho teve como objetivo estudar o desempenho de pontas de pulverização na deposição da calda inseticida para o controle de ninfas de cigarrinhas das pastagens em Brachiaria brizantha cv. MG-4. Doze tratamentos foram estudados em esquema fatorial 6x2, constituídos pelo contraste de seis pontas de pulverização e pressões de 196 e 392 kPa: TF-VP2 (336 L ha-1 e 467 L ha-1); AI11002-VS (184 L ha-1 e 200 L ha-1); XR11002-VS (200 L ha-1 e 280 L ha-1); TT11002-VP (200 L ha-1 e 280 L ha-1); TJ60-11002VS (208 L ha-1 e 280 L ha-1) e TX-VK4 (72 L ha-1 e 97 L ha-1). Para monitorar a deposição das caldas de pulverização, utilizaram-se os traçadores Azul Brilhante FD&C-1 (0,3% p/v) e Amarelo de Tartrasina FD&C-5 (0,6% p/v). Alvos artificiais, constituídos de lâminas de vidro, foram posicionados na base das plantas, próximos à superfície do solo, e os depósitos por unidade de área das soluções pulverizadas foram quantificados por espectrofotometria. As pontas TF-VP2, XR11002-VS e AI11002-VS, nas pressões de 196 e 392 kPa, proporcionam as maiores deposições da calda de pulverização na região das espumas das cigarrinhas das pastagens, apesar de apresentarem menor uniformidade na distribuição dos depósitos em relação a TX-VK4, XR110.02-VS e TJ110.02-VS. O aumento da pressão de 196 para 392 kPa promoveu aumento na deposição da calda de pulverização sobre a Brachiaria brizantha e na região onde se encontram as espumas das cigarrinhas para todos os tipos de pontas estudadas.

Secagem do resíduo industrial da acerola em leito de jorro: estudos fluidodinâmicos e análise do desempenho do secador

In this research, the drying process of acerola waste was investigated by using a spouted bed drier. The process was conducted using high density polyethylene inert particles with the objective of producing an ascorbic acid-rich final product. The fruit waste was ground and used to prepare different water-maltodextrin suspensions. Initially, fluidynamical experiments were conducted in order to evaluate the feeding effect on the spouted bed drier fluidynamics behavior. The experimental planning 23 + 3 was used to investigate the effect of the following variables: solids concentration, drying air temperature, intermittence time, production efficiency, solids retention and product losses by elutriation of fine particles on drier walls. The effect of selected independent variables on the drier stability was also evaluated based on a parameter defined as the ratio between the feed suspension volume and the total inert particles volume. Finally, the powder quality was verified in experiments with fixed feed flow and varying air drying temperature, drying air velocity and intermittence time. It was observed that the suspension interferes in the spouted bed drier fluidynamics behavior, and higher air flow is necessary to stabilize the drier. The suspension also promotes the expansion of the spouted bed diameter, decreases the solid circulation and favors the air distribution at the flush area. All variables interfere in the spouted bed performance, and the solids concentration has a major effect on the material retention and losses. The intermittence time also has great effect on the stability and material retention. When it comes to production efficiency, the main effect observed was the drying air temperature. First order models were well adjusted to retention and losses data. The acerola powder presented ascorbic acid levels around 600 to 700 mg/100g. Similar moisture and ascorbic acid levels were obtained for powders obtained by spouted bed and spray drier. However, the powder production efficiency of the spray drier was lower when compared to spouted bed drier. When it comes to energetic analysis, the spray drier process was superior. The results obtained for spouted bed drier are promising and highly dependent on the operational parameters chosen, but in general, it is inferred that this drying process is adequate for paste and suspension drying

Desempenho operacional e custos da operação de subsolagem em área de implantação de eucalipto

The knowledge of operating performance of agricultural machinery has become a crescent concern and of utmost importance since mechanized production costs are directly affected by the efficiency of the machine in the field. This study determined the operational performance and economy of a tractor in the subsoiling operation in function of slope classes. The analysis technique included a time and movement study and the economic analysis of the parameters operational cost, production cost and energy consumption. on the classes of slope evaluated, increasing the percentage of inclination of relief, lowered the operational performance and increased the production costs. The cost of fuel represented the greatest percentage among those that make up the operational cost.

Formulação de novos combustíveis base diesel: avaliação de desempenho e emissões

The industry, over the years, has been working to improve the efficiency of diesel engines. More recently, it was observed the need to reduce pollutant emissions to conform to the stringent environmental regulations. This has attached a great interest to develop researches in order to replace the petroleum-based fuels by several types of less polluting fuels, such as blends of diesel oil with vegetable oil esters and diesel fuel with vegetable oils and alcohol, emulsions, and also microemulsions. The main objective of this work was the development of microemulsion systems using nonionic surfactants that belong to the Nonylphenols ethoxylated group and Lauric ethoxylated alcohol group, ethanol/diesel blends, and diesel/biodiesel blends for use in diesel engines. First, in order to select the microemulsion systems, ternary phase diagrams of the used blends were obtained. The systems were composed by: nonionic surfactants, water as polar phase, and diesel fuel or diesel/biodiesel blends as apolar phase. The microemulsion systems and blends, which represent the studied fuels, were characterized by density, viscosity, cetane number and flash point. It was also evaluated the effect of temperature in the stability of microemulsion systems, the performance of the engine, and the emissions of carbon monoxide, nitrogen oxides, unburned hydrocarbons, and smoke for all studied blends. Tests of specific fuel consumption as a function of engine power were accomplished in a cycle diesel engine on a dynamometer bench and the emissions were evaluated using a GreenLine 8000 analyzer. The obtained results showed a slight increase in fuel consumption when microemulsion systems and diesel/biodiesel blends were burned, but it was observed a reduction in the emission of nitrogen oxides, unburned hydrocarbons, smoke index and f sulfur oxides