RESUMONo cenário atual brasileiro de constantes quedas de energia e iminência de uma crise no setor elétrico, a utilização de grupos geradores tem sido bastante comum no meio rural e os bicombustíveis, como o biodiesel, representam uma opção para diversificação da matriz energética. Este trabalho objetivou avaliar o uso do biodiesel de soja em diferentes concentrações em um motor de ciclo diesel sob diferentes demandas de cargas do motor. Foram utilizadas as concentrações: 5% (B5), 10% (B10), 20% (B20), 50% (B50), 75% (B75) e 100% de biodiesel (B100) em um grupo gerador a diesel, com motor de 5 Hp de quatro tempos, em diferentes condições de operação do motor, por meio de demandas de cargas elétricas: 500, 1.000, 1.500, 2.000 W e desligadas conectadas ao grupo gerador. Foram realizados ensaios para quantificação do consumo horário de combustível e da emissão de gases. As variáveis sofreram influência significativa conforme foram alteradas as cargas elétricas e as misturas de combustível. O uso do biodiesel em concentrações maiores reduz consideravelmente a emissão da maioria dos gases poluentes e se tem praticamente anulada a emissão de enxofre para concentrações acima de 65% de biodiesel. Palavras-chave: biocombustíveis, geração de energia, eficiência energética, gases estufaPerformance and emissions of a diesel engine-generator cycle under different concentrations of soybean biodiesel ABSTRACT In the current scenario of constant power drops in Brazil and an imminent crisis in the electricity sector, the use of generators and biofuels such as biodiesel has been quite common in rural areas represents an option for diversification of the energy matrix. This study evaluated the use of soybean biodiesel in different concentrations in a diesel engine cycle under different demands of engine loads. Concentrations used were: 5% (B5), 10% (B10), 20% (B20), 50% (B50), 75% (B75) and 100% biodiesel (B100) in a diesel generator with engine of 5 Hp of four-stroke under different operating conditions of the engine, through the demands of electrical loads: 500, 1.000, 1.500, 2.000 W and off connected to the generator. Tests were conducted to quantify the hourly consumption of fuel and gas emissions. The variables suffered significant influence as the electrical charges and fuel mixtures were changed. The use of biodiesel in higher concentrations considerably reduces the emission of majority of pollutant gases and practically nullified the emission of sulfur in concentrations above 65% biodiesel.

RESUMODentre os equipamentos utilizados em uma operação agrícola o trator é o principal. Durante a jornada de trabalho os operadores são submetidos a várias intensidades de ruído, tornando necessário seu estudo para o desenvolvimento de tratores e ambientes mais adequados para os usuários dessa máquina.O trabalho visa estudar o comportamento do nível de ruído emitido por trator agrícola em função do raio de afastamento quando em diferentes ambientes de trabalho e rotações do motor. O experimento foi realizado na Estação Experimental da EMATER, de Anápolis, GO. Foi utilizado, como fonte de ruído, um trator New Holland, potência de 55,1 kW (75 cv). A medição do nível de ruído foi realizada por um decibelímetro digital, de acordo com a NBR 9999 (ABNT, 1987). Visando-se à medição do ruído em diferentes ambientes, utilizou-se um galpão de 250 m 2 como ambiente fechado além de um campo livre de obstáculos, como ambiente aberto. O raio de afastamento foi determinado por cinco diferentes distâncias e nas quatro diferentes direções em relação ao operador do trator. As rotações do motor foram 1000, 1500, 2000, 2500 rpm. Para interpretação dos dados foram realizados dois experimentos em delineamento inteiramente casualizado, com três repetições, interpretados pelo teste de Tukey a 5% e geoestatística. A geoestatística demonstrou-se satisfatória para a análise do comportamento do ruído ao redor do trator. Os cuidados em relação ao nível de ruído emitido pelo trator devem ser aguçados quando utilizado em operações estacionárias em ambientes fechados. Palavras-chave: ambiente, geoestatística, mecanização agrícola, raio de afastamento Spatial analysis of the noise emitted by a farm tractor ABSTRACTAmong the equipments used in a farming operation, the tractor is the principal. During working hours the operators are subjected to various intensities of noise, making it necessary the development of tractors and environments more suitable for users of this machine.This study demonstrates the behavior of the noise level emitted by a tractor when it is working under different environment due to clearance radius at different engine speeds. The experiment was conducted at the EMATER experimental station in Anápolis -GO. A New Holland tractor, power 55.1 kW (75 cv), was used as a source of noise. The noise level was performed by a digital sound level meter according to parameters established by NBR 9999. For measurement of noise in different environments, a shed of 250 m 2 was used as indoor environment and a field free of obstacles such as open environment. The radius of removal was determined by five different distances (1, 2, 3, 4 and 5 m) and in four different directions in relation to the tractor. The engine speeds were 1000, 1500, 2000, 2500 rpm. For the interpretation of data, two experiments were carried out in a completely randomized, with three replications, interpreted by the Tukey´s test (5%) and geostatistics. The geostatistical analysis showed satisfactory to the behavior of the noise around the tractor. Care in relation t...

The objective of this study was to evaluate the effect of drying at different temperatures on the physical properties of the grains; water content, volumetric contraction, the weight of thousand grains, apparent specific mass, length, width, thickness, circularity, sphericity, and comparison of methodologies of soybeans. To evaluate the physical properties, the soybean grain samples with an initial water content of 19.06% b.u. were subjected to the effects of drying air temperatures heated to 40ºC, 55ºC, 70ºC, and 85ºC. The samples were dried in a conventional natural convection oven until reaching 19% water contents, 17%, 15%, 13%, and 11% b.u. Subsequently, the drying curve of soybeans dried under different temperatures was characterized and the physical properties of an apparent specific mass, the weight of one thousand grains, and volumetric contraction were analyzed. It was noted that the increase in temperature affected the three-dimensional axes of the grains, causing them to lose water to the drying air. However, when these grains are dried at high temperatures spending less time, their characteristics are modified. The weight of the grains and the apparent specific mass decreased with increasing temperature during drying. The circularity, sphericity, and unit volume decreased with the increase in temperature during drying, therefore, it is not possible to use the new proposal of digital methodology instead of manual measurement, since the correlation between the two methodologies is close to zero. For the conditions under which the experiment was carried out, it can be concluded that with the increase in the temperature of the drying air, the grains dry faster, and yet the physical dimensions are more preserved, not being intensely reduced throughout the process.

The objective of this study was to develop and calibrate a photovoltaic-powered soil moisture sensor (SMS) for irrigation management. Soil moisture readings obtained from the sensor were compared with gravimetric measurements. An automated SMS was used in two trials: (i) okra crop (Abelmoschus esculentus) and (ii) chili pepper (Capsicum frutescens). All sensors were calibrated and automated using an Arduino Mega board with C++. The soil moisture data were subjected to descriptive statistical analysis. The data recorded by the equipment was correlated with the gravimetric method. The determination coefficient (R2), Pearson correlation (r), and root mean square error (RMSE) were adopted as criteria for equipment validation. The results show that our SMS achieved an R2 value of 0.70 and an r value of 0.84. Notably, there was a striking similarity observed between SMS and gravimetric data, with RMSE values of 3.95 and 4.01, respectively. The global model developed exhibited highly efficient outcomes with R2 (0.98) and r (0.99) values. The applicability of the developed SMS facilitates irrigation management with accuracy and real-time monitoring using digital data. The automation of the SMS emerges as a real-time and precise alternative for performing irrigation at the right moment and in the correct amount, thus avoiding water losses.