Adílio Flauzino de Lacerda Filho

Qualidade dos grãos de soja armazenados em diferentes condições

This study was conducted to evaluate the quality of soy bean grains stored under different conditions. The grains were harvested with moisture content (m. c.) of about 18.0% w.b. and dried to 11.2, 12.8 and 14.8% w.b. To maintain pre-determined m.c., the grains were stored at the following combinations of temperature and relative humidity: for 11.2%: 20 oC and 61.7%; 30 oC and 67.9%; 40 oC and 69.4%; for 12.8%: 20 oC and 73.7%; 30 oC and 76.7%; 40 oC and 80.8%; and for 14.8%: 20 oC and 82.7%; 30 oC and 83.9%; 40 oC and 85.3%. Grains were sampled every 45 days over 180 days in order to determine m.c., grade classification, apparent specific grain mass, grain color and oil content. In general, the grains deteriorated during the storage period but the quality loss was more accentuated when stored with m.c. of 12.8 and 14.8% at 40 oC. The grains stored with m.c. of 14.8% at 30 and 40 oC did not meet commercial standards after 135 and 90 days, respectively. High m.c. and temperature during storage intensify the deteriorative processes of stored soy bean grains.

Three-Dimensional Modeling and Simulation of Heat and Mass Transfer Processes in Porous Media: An Application for Maize Stored in a Flat Bin

If the relative humidity and temperature of the air inside a granular mass of stored grain exceeds a certain threshold value, microorganism activity is likely to increase. Lower relative humidity and temperature, when uniformly distributed inside the grain mass, prevent moisture migration and an increase in microorganism activity. To cool down or maintain the temperature of the grain mass below a threshold value, forced ventilation with an appropriate airflow can be used to remove excess moisture or heat generated by grain or microorganism respiration. The objective of this work was to solve the equations that describe the conservation of heat, mass, and momentum in order to predict heat and mass transfer processes in the environment inside a grain mass of maize, stored in a flat bin. Three-dimensional computational fluid dynamics was used to solve the equations. The analysis of heat and mass transfer was performed considering the geometry of a two-ton-capacity bin prototype using a hexahedral mesh for the finite volume analysis. The numerical grid was defined to discretize the physical flow domain of interest to calculate velocity, temperature, and moisture distribution in the bulk of stored grain. The predicted results were compared with experimental data, and the agreement between them was very good.

Simulação do processo de secagem de sementes de milho em camada fixa

Artificial drying is one of the main problems of seed production, hence it affects quality of grains, and can decrease considerably their market value. This work aimed to develop a mathematical model to simulate a corn seed drying process. Simulation results were validated by comparison to experimental results. The drying method consisted of a fixed-bed, pre-drying of corn (Zea mays L.) ears, which were then kept on rest for 12 hours. After that the product was threshed and kernels were submitted to a final drying process on a fixed bed dryer: bins with radial air distribution. Air temperature was 42°C; specific air rate of the ear corn dryer was 44.8 m3 min-1 m-2 and of the drying bin 5.9 m3 min-1 m-2. The error of the average simulation model was 10.88%, which was considered satisfactory.

Efeitos de diferentes estratégias de controle no ambiente de armazenamento de grãos em regiões tropicais e subtropicais.

In this work, control strategies for grain aeration based on timer, thermostat and thermostat combined with humidistats were compared to the AERO controller. In spite of the simplicity of the first three strategies, they are widely used, resulting in reliable control and high acceptance by farmers. AERO was developed at the Federal University of Vicosa to spread and facilitate the use of more sophisticated strategies by farmers. This controller is based on real time data acquisition and process simulation. The results showed that aeration time, as well as final grain deterioration rates, temperatures and moisture contents were similar among the four strategies, when considering the best set-points of the three simple controllers. However, AERO resulted in a more effective control, cooling the grain mass more quickly and reducing temperature and moisture content oscillations during the aeration process. Another advantage of AERO is its capacity of automatically adjust its set-points according to the weather conditions of the region where the aeration system is operating.

Racionalização do uso de força motriz em fábrica de ração

A falta de investimento no setor energetico, aliada a sazonalidade de recursos naturais necessarios para a geracao de energia hidroeletrica, faz da racionalizacao do uso de energia eletrica uma ferramenta de apoio imprescindivel para o crescimento do Pais. A racao animal pode representar entre 70 e 80% do custo de producao da criacao de animais. Sendo assim, e importante o estudo da racionalizacao do uso de energia em processos que utilizam intensivamente forca motriz, tais como as fabricas de racao. Na fabrica de racao estudada, os motores eletricos sao utilizados principalmente para moagem e mistura de granulados e transporte. Com o objetivo de racionalizar o uso da energia eletrica, foi realizado estudo de adequacao de forca motriz dos equipamentos da fabrica de racao da Industria Pif Paf Alimentos. O indice de carregamento medio dos motores eletricos estudados foi de 48,6%. O potencial estimado total de economia com energia eletrica anual, utilizando-se sempre da melhor opcao de adequacao de forca motriz foi de R

Secagem de café em combinação

24.426,50 ao ano (23,9%). Para que essas medidas sejam efetivadas, devem-se adequar tambem: (i) as exigencias eletricas do circuito, como ajuste de reles e escolha de fusiveis; (ii) o horario de funcionamento, e (iii) necessidade de implantacao de sistema de armazenamento de racao.

Demanda de potência do ventilador para aeração de material em compostagem

The general objective of this study was the evaluation of a system for coffee drying, using partial drying in fixed bed dryer and complementary drying in an intermittent concurrent flow batch dryer. The experiment was carried out in the Vegetable Products Processing Area, DEA-UFV. The drying tests were accomplished in completely randomized design. The coffee was harvested on the ground by manual striping process. The fruits were pre-processed by drying of ripe, overripe and greenish cherries. For the preliminary drying, the initial coffee moisture content varied from 68.9 to 71.3% w.b. with the drying being interrupted with moisture content between 44.0 and 47.5% w.b. In the complementary drying phase the final moisture varied between 12.2 and 13.8% w.b. The temperature of the drying air, in the fixed-bed dryer, varied from 50.4 to 76 °C, and in the concurrent flow batch dryer, between 87.2 and 110 °C. The specific enthalpies were 8.4 to 9.1 MJ kg-1 and 7.1 to 16,9 MJ kg-1 for the fixed-bed dryer and concurrent flow batch dryer, respectively. In comparison with the control tests, the final quality of the product presented better commercial characteristics. It was concluded that with preliminary drying in fixed bed dryer and complementary drying in a concurrent flow dryer, besides reducing the total drying time, the combined system contributes to a better preservation of qualities acquired in field.

Modeling and Simulation of the Transient Response of Temperature and Relative Humidity Sensors with and without Protective Housing

This study aimed to adjust loss curves in static air pressure when forced into layers of organic material, with different thicknesses and two stages of biochemical degradation, to enable the calculation of the power demand of the ventilation system. The residues used to evaluate air pressure loss were poultry litter mixed with coffee cherry husk, mass ratio of 2.5:1, to obtain an initial C/N relation of 30:1. It was found that the loss in static pressure increased linearly with the thickness of the organic compound, and that there was an increase in static pressure loss with increased specific flow rate of air, which practically did not change by the biochemical degradation stage of the composting material. All models used (potential, logarithmic and quadratic) fit the experimental data in the range of specific air flow between 0.045 and 0.159 m 3 s -1 m -2 , and they may be used to predict the static pressure gradients in the organic compost. The power demanded by the ventilation system in layers of 1 m thickness was 1.16 W t -1 in the material before composting, and 2.38 W t -1 , after 60 days of composting. In layers of 2 m thickness, the demand was 17.70 and 21.65 W t -1 , respectively.This study aimed to adjust loss curves in static air pressure when forced into layers of organic material, with different thicknesses and two stages of biochemical degradation, to enable the calculation of the power demand of the ventilation system. The residues used to evaluate air pressure loss were poultry litter mixed with coffee cherry husk, mass ratio of 2.5:1, to obtain an initial C/N relation of 30:1. It was found that the loss in static pressure increased linearly with the thickness of the organic compound, and that there was an increase in static pressure loss with increased specific flow rate of air, which practically did not change by the biochemical degradation stage of the composting material. All models used (potential, logarithmic and quadratic) fit the experimental data in the range of specific air flow between 0.045 and 0.159 m3 s-1 m-2, and they may be used to predict the static pressure gradients in the organic compost. The power demanded by the ventilation system in layers of 1 m thickness was 1.16 W t-1 in the material before composting, and 2.38 W t-1, after 60 days of composting. In layers of 2 m thickness, the demand was 17.70 and 21.65 W t -1, respectively.

Determination of the influence of the variation of reducing and non-reducing sugars on coffee quality with use of artificial neural network

Based on the necessity for enclosure protection of temperature and relative humidity sensors installed in a hostile environment, a wind tunnel was used to quantify the time that the sensors take to reach equilibrium in the environmental conditions to which they are exposed. Two treatments were used: (1) sensors with polyvinyl chloride (PVC) enclosure protection, and (2) sensors with no enclosure protection. The primary objective of this study was to develop and validate a 3-D computational fluid dynamics (CFD) model for analyzing the temperature and relative humidity distribution in a wind tunnel using sensors with PVC enclosure protection and sensors with no enclosure protection. A CFD simulation model was developed to describe the temperature distribution and the physics of mass transfer related to the airflow relative humidity. The first results demonstrate the applicability of the simulation. For verification, a sensor device was successfully assembled and tested in an environment that was optimized to ensure fast change conditions. The quantification setup presented in this paper is thus considered to be adequate for testing different materials and morphologies for enclosure protection. The results show that the boundary layer flow regime has a significant impact on the heat flux distribution. The results indicate that the CFD technique is a powerful tool which provides a detailed description of the flow and temperature fields as well as the time that the relative humidity takes to reach equilibrium with the environment in which the sensors are inserted.

Electric motor efficiency as parameter for sizing a directly connected into transformer feeder cable.

Este trabalho teve como objetivo avaliar a utilizacao de Rede Neural Artificial para correlacionar os valores resultantes de analises quimicas de amostras de cafe com os valores da sua analise sensorial. As amostras de cafe utilizadas foram referentes ao cafe Coffea arabica L., cultivar Acaia do Cerrado, Topazio, Acaia 474-19 e Bourbon, coletados na regiao Sul de Minas Gerais. As analises quimicas foram de acucar nao redutor e acucar redutor sendo a qualidade da bebida avaliada pela analise sensorial. O metodo de Rede Neural Artificial utilizou os valores das analises quimicas como variaveis de entrada e os valores da analise sensorial como valores de saida. A regressao linear multipla dos valores de analise sensorial em funcao dos valores das analises quimicas teve coeficiente de determinacao de 0,3106, enquanto o metodo de Rede Neural Artificial empregado obteve um nivel de acerto na classificacao dos valores da analise sensorial de 80%.Este trabalho teve como objetivo avaliar a utilizacao de Rede Neural Artificial para correlacionar os valores resultantes de analises quimicas de amostras de cafe com os valores de sua analise sensorial. As amostras de cafe utilizadas foram referentes ao cafe Coffea arabica L., cultivar Acaia do Cerrado, Topazio, Acaia 474-19 e Bourbon, coletados na regiao sul de Minas Gerais. As analises quimicas foram de acucar nao redutor e acucar redutor, sendo a qualidade da bebida avaliada pela analise sensorial. O metodo de Rede Neural Artificial utilizou os valores das analises quimicas como variaveis de entrada e os valores da analise sensorial como valores de saida. A regressao linear multipla dos valores de analise sensorial, em funcao dos valores das analises quimicas, teve coeficiente de determinacao de 0,3106, enquanto o metodo de Rede Neural Artificial empregado obteve um nivel de acerto na classificacao dos valores da analise sensorial de 80,00%.