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In this study, a biodiesel was produced from blending vegetable and animal sources with diesel and diesel-ethanol using a motor-generator set to evaluate its performance and emission characteristics. Fifteen and twenty percent of animal-vegetable biodiesel were added to each diesel-ethanol blend. A motor-generator test was conducted for each mixture; each sample was subjected to resistive loads from 2 to 5 kW with six repetitions. The physicochemical properties met the national standard guidelines, while the best specific fuel consumption (SFC) was observed for the 15% biodiesel-1% ethanol (B15E1) blend at the load of 5 kW with 327.069 g kW h, followed by diesel (334.875 g kW h). The exhaust gas temperature behaved differently depending on the ethanol concentration; it was lower when the concentration of added ethanol was higher. The NO emissions decreased while the SO emissions increased as the ethanol concentration increased.

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Beauregard sweet potatoes have high concentration of β‐carotene, a precursor of vitamin A, which helps in human growth and development. The objective of the work was to optimize the Beauregard sweet potato flour production process, maintaining a high content of carotenoids. A central rotational composite design 23 was performed with three central points and six axial points. Independent factors were ascorbic acid concentration, immersion time, and drying temperature while investigated responses were carotenoid, vitamin C and protein content and color. The optimum conditions for the processing of sweet potato flour was ascorbic acid concentration used in the immersion of 1.84 g 100 ml–1, immersion time of 43.6 min, and drying temperature of 43.3°C. The process showed 100% general desirability, and the product obtained present 419.85 μg g–1 of carotenoids, 24.92 mg 100 g–1 of vitamin C, and 5.26 mg 100 g–1 of protein content. Practical applications Sweet potato (Ipomoea potatoes L. (Lam.)) is an energetic food, containing a high content of vitamins and minerals. The Beauregard variety, with orange pulp, has advantages over other cultivars because it has high productivity and is more nutritious due to its high content of β‐carotene (115 μg g–1 of fresh roots), in addition to different color and flavor. The drying process of roots for the production of flour is a method most used to reduce post‐harvest losses that occur due to its high perishability. The use of experimental planning through a central rotational composite design (DCCR) is an efficient statistical tool that allows determining the ideal conditions of the Beauregard sweet potato flour production process in which the high nutritional value is maintained, preserving the B‐carotene) and with less alteration of the color sensory attribute.

RESUMO:A dificuldade de obter distribuição uniforme dos resíduos, na largura de corte da plataforma da colhedora, tem sido constatada visualmente em culturas comerciais. Assim, o objetivo deste trabalho foi avaliar a uniformidade de distribuição transversal de palha por colhedoras autopropelidas na colheita da soja. Foram avaliadas nove colhedoras nas condições de operação e regulagem que estavam sendo usadas pelo operador. Foi utilizado o coeficiente de variação para a comparação das máquinas e a avaliação da uniformidade de distribuição, e realizada análise multivariada para avaliar a similaridade entre as colhedoras em função do coeficiente de variação, umidade da palha e largura da plataforma de corte. Todas as colhedoras apresentaram distribuição desuniforme de palha, resultando em faixas com elevada concentração da mesma na parte central da linha de deslocamento da colhedora e pouca nas extremidades, independentemente da largura da plataforma de corte. Apenas uma colhedora apresentou distribuição próxima da ideal, por possuir também um sistema distribuidor para a palha proveniente das peneiras. Constatou-se que a palha oriunda das peneiras da colhedora pode ser a responsável pela formação das faixas com elevadas quantidades de palha na linha central, independentemente do tamanho da máquina. PALAVRAS-CHAVE: máquinas agrícolas, plantio direto, resíduo vegetal. STRAW DISTRIBUTION FOR COMBINES IN THE HARVEST OF SOYBEAN ABSTRACT:The difficulty of getting a uniform residues distribution, in the width of the combine cutting ban, have been observed in crop fields. The objective of this work was to evaluate the uniformity of straw distribution for combines harvesting soybean. It was appraised nine combines in the operation conditions and adjustment that they were being used by the operator. The Coefficient of Variation (CV) was used for comparison of the machines and the evaluation of the distribution uniformity, and had accomplished a multivariate analysis to evaluate the similarity among the combines in function of the coefficient of variation, humidity of the straw and width of the cut platform. All the combines had presented a disuniform straw distribution, resulting in bands, with raised straw concentration in the combine central part and little in the extremities, independently of the width of the cut platform. But a combine presented distribution next to the ideal, for also possessing a delivering system for the straw proceeding from the bolters. One evidenced that the deriving straw of the combine bolters can be the responsible for the formation of bands with raised amounts of straw in the combine center, independently of the machine size.

ABSTRACT. The increasing deployment of biodigesters for the treatment of waste on farms and the use of the biogas generated in the production of energy have highlighted the need for knowing the influence of this fuel on internal combustion engines. This study aimed to analyze the influence of filtrated biogas on lubricant oil contamination and degradation, as well as on engine wear and corrosion. Lubricant oil samples were collected every 75 engine operating hours (EOH) and then correlated between each other and with a sample of new oil, determining the elements present in the biogas that contribute to lubricant oil contamination and degradation, as well as lubricant oil performance in the course of EOH and engine wear. The results demonstrate that hydrogen sulfide affects the performance of the lubricant oil and engine wear. Among the metals, we observed that the copper concentration exceeded the maximum limit recommended in the literature. As for the additives, the variation in concentrations of magnesium impacted on lubricant performance. By monitoring lubricant oil quality were able to extend the engine oil change interval of this study by 50%, what resulted in a savings of 33.3% in the cost of lubricant per hour worked.Keywords: contaminants, biogas, biodigester, biomethane, corrosion.Análise da contaminação e degradação do óleo lubrificante e desgaste de um motor ottolizado alimentado por biogás RESUMO. A crescente implantação de biodigestores para tratamento de resíduos nas propriedades rurais e a utilização do biogás gerado na produção de energia mecânica evidenciaram a necessidade de conhecimento da influência de utilização deste combustível nos motores de combustão interna. Este trabalho teve como objetivo analisar a influência da utilização do biogás filtrado na contaminação e degradação do óleo lubrificante, desgaste e corrosão do motor. Amostras de óleo lubrificante foram coletadas a cada 75 hM (horas de funcionamento do motor), e após correlacionadas dentre elas e com uma amostra de óleo novo, determinando os elementos presentes no biogás que contribuem para a contaminação e degradação do óleo lubrificante, como também o desempenho do lubrificante no decorrer das hM e o desgaste do motor. Os resultados demostraram que o gás sulfídrico influencia no desempenho do óleo lubrificante e no desgaste do motor. Dentre os metais, foi identificado que a concentração de cobre excedeu o máximo recomendado pela literatura, e a elevação da sua concentração teve relação com a elevação de chumbo e estanho, principalmente após as 375 hM. Em relação aos aditivos, foi a variação das concentrações de magnésio que impactou no desempenho do lubrificante. Por meio do monitoramento da qualidade do lubrificante é possível estender o intervalo de troca de óleo do motor do presente estudo em 50%, resultando em uma economia de 33,3% no custo do lubrificante por hora trabalhada.