ABSTRACT The combination of crambe (Crambe abyssinica L.) biodiesel and biogas could be a renewable energy alternative for internal combustion engines. Therefore, the emissions and engine performance of crambe biodiesel blends (B0, B10, B30, B50, B75, and B100) were evaluated in both the dual mode (biogas) and normal mode (biodiesel). The tests were performed on a 5-kVA generator engine at loads ranging from 1 to 4 kW. The power generated in the normal mode was 17% lower than that generated in the dual mode. The dual mode showed a lower specific fuel consumption than the normal mode. In the normal mode, loss of power occurred as the proportion of biodiesel increased. Furthermore, nitrogen oxide emissions decreased with the addition of biogas. In the dual mode, the emissions increased as the biodiesel content increased. Carbon monoxide emissions decreased in both the normal and dual modes with an increase in biodiesel. The addition of biogas in the dual fuel mode with crambe biodiesel is an efficient alternative for partial substitution of diesel.

ABSTRACT The defects that drying in concrete yards impose on coffee beans and the search for gourmet coffee production have prompted the emergence of new drying technologies. This work verified the technical and economic feasibility of drying coffee with dehumidified air with a refrigerating capacity of 422,908.7 J s-1, compatible with static capacity dryers equal to 75 m3. Considering the sale price of coffee, the cost of electric energy acquisition, the monthly interest rate and maintenance time, expenses that are equivalent to the depreciation of the concrete yard, a central compound rotational design was considered with 28 tests for the feasibility analysis, including the internal rate of return, net present value and the return on investment. The results showed that in the electric drying units, the dried coffee presents fewer broken and defective beans and has higher retention in a No. 17 sieve. With a higher beverage quality and a price 12.11% higher, drying with dehydrated air showed a PBD of 2.27 years and a return of US$ 2.49 million. The optimisation results were 98.98% desirable. It was concluded that it is economically feasible to dry coffee with dehydrated air and without using a concrete yard.

ABSTRACT Grain drying processes have been improved to reduce costs and losses of coffee beverage quality. The objectives of this study were to evaluate the quality of coffee dried using air partially dehumidified before entering drying units (DUs) in four coffee-producing farms, as well as the effects of such process on coffee commercial value. The method consisted of obtaining three samples (triplicates) of coffee dried in both DUs and concrete terraces (control) for mean multiple comparisons. The following variables were analyzed for sieve #13 and hand-picked beans: defect number, cupping test, and pricing. Evaluations were carried out by three professional graders. The results showed that coffee dried in the DUs presented fewer broken grains, higher cupping score, and less negative factors of handsorting and defects. As a conclusion, it should be emphasized an average increase of 12.11% in price for coffee beans previously dehumidified.

Resumo: As perdas da agroindústria são geralmente de produtos úmidos que devem ser secos para posterior uso e armazenamento. Para otimizar os processos de secagem, o estudo das isotermas e propriedades termodinâmicas torna-se essencial para entender os mecanismos de sorção de água dos produtos agrícolas. Assim, o objetivo neste estudo foi determinar e avaliar as propriedades termodinâmicas para diferentes teores de água de equilíbrio em sementes de crotalária (Crotalaria spectabilis Roth), usando o método estático direto para obter os dados experimentais. O modelo de Chung-Pfost foi usado para determinar as propriedades termodinâmicas de sementes de crotalária. De acordo com os resultados, as propriedades termodinâmicas são influenciadas pelo teor de água. O calor latente da vaporização de água aumentou com a diminuição do teor de umidade de equilíbrio. O processo de dessorção das sementes de crotalária foi controlado pela entropia. A energia livre de Gibbs foi negativa, indicando que o processo de dessorção de sementes de crotalária foi espontâneo.

Abstract: Losses of agroindustry are generally wet products that must be dried to posterior use and storage. In order to optimize drying processes, the study of isotherms and thermodynamic properties become essential to understand the water sorption mechanisms of agricultural products. Thus, the objective in this study was to determine and evaluate the thermodynamic properties for different equilibrium moisture contents in sunn hemp (Crotalaria spectabilis Roth) seeds, using the direct static method to obtain the experimental data. The Chung-Pfost model was used to determine the thermodynamic properties of sunn hemp seeds. In according to results, thermodynamic properties were influenced by moisture content. The water vaporization latent heat increased with the decrease in equilibrium moisture content. The sunn hemp desorption process was controlled by entropy. Gibbs free energy is negative indicating that the desorption process of sunn hemp seeds was spontaneous.

ABSTRACT In Brazil there is a wide availability of residues, which have been used in the production of biogas and biofertilizers. The engine-generator by biogas is grid connected, and produce electricity for self-consumption and the surplus is inserted into the grid. The aim of the present study was to evaluate energetic efficiency and exhaust gas emission of two cases: two engine-generators sets of 100 kVA running on biogas, produced from residues of a poultry slaughterhouse unit (PSU) and swine fattening unit (SFU). Load variation in the engine-generator set was evaluated in the SMCP (system of protection and synchronism). There was an increase in the emission of nitrogen oxide, sulfur dioxide and exhaust gas temperature, in both cases. The elevation in the load of the engine-generator increased its global efficiency (mechanical plus electric), with levels between 6.12% with load of 10 kW and 20.91% with 70 kW. The average specific consumption of biogas in the load of 70 kW was 0.76 m3 kWh-1 in the swine fattening unit and 0.80 m3 kWh-1 in the slaughterhouse unit with load of 70 kW. The last results show an engine-generator on biogas of 100 kVA (load of 70 kW), spent an average of 1.4 m3 of biogas to produce 1.0 kWh of electricity.

A garantia de sementes com elevado vigor e boa qualidade é fundamental para o sucesso de qualquer cultura. Sementes com baixo vigor podem apresentar dificuldades na germinação e emergência em campo, sob condições não favoráveis, como a falta de umidade ou baixas temperaturas. Portanto, os produtores, na tentativa de reduzir custos de produção, têm separado grãos da safra produzida para serem utilizados como sementes e isso tem sido cada vez mais frequente. Assim, este trabalho teve como objetivo avaliar o potencial fisiológico de sementes de soja Roundup Ready com sementes convencionais, e comparar sementes “salvas”, produzidas por um produtor com sementes comerciais. As sementes foram caracterizadas em laboratório (pureza, massa de mil sementes e teor de água), submetidas a testes de vigor (envelhecimento acelerado, teste de frio e condutividade elétrica), teste de germinação, emergência em areia, índice de velocidade de emergência, crescimento de plântulas, comprimento de raízes e parte aérea das plântulas e matéria fresca e seca. Foi possível identificar maior pureza nas sementes comerciais do que nas sementes “salvas”. Os lotes das cultivares convencionais apresentaram potencial fisiológico superior às cultivares de soja Roundup Ready, porém, entre as sementes “salvas” e comerciais não houve diferença quanto ao vigor.

The guarantee of seeds with high vigor and good quality is the most important characteristic for the success in soybean cropping. Seeds with low vigor may show some difficulty on germination and field emergence, mainly under adverse conditions, such as moisture deficiency or low temperatures. Thus, this study aimed at evaluating the physiological potential of Roundup Ready (RR) and conventional soybean seeds, 'saved' by a farmer as well as commercial seeds. Nevertheless, some farmers, in an attempt to reduce production costs, have already separated cropped grains produced to be used as seeds and it has been increasingly common. So, this trial aimed at evaluating the physiological potential of Roundup Ready soybean seeds with conventional seeds, and compare the 'saved' seeds, produced by a farmer with commercial seeds. The seeds were characterized in the laboratory (purity, mass of thousand seeds and moisture content). Vigor (accelerated aging, cold test and electrical conductivity test), germination test, emergence on sand, emergence speed index, seedling growth, roots and shoots length of seedlings as well as fresh and dry matter were determined. It was possible to identify that the commercial seeds showed higher purity when compared to the saved ones. Plots of conventional cultivars showed higher physiological potential, and there was no difference concerning the vigor between the ‘saved’ seeds and commercial ones.