Engenharia Agrícola - Artigos
URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11739
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Item Mathematical models to describe the volumetric shrinkage rate of red beans during drying(Engenharia Agrícola, 2011-07) Corrêa, Paulo C.; Resende, Osvaldo; Garin, Silvia A.; Jaren, Carmen; Oliveira, Gabriel H. H. deThe present study aimed to determine the volumetric shrinkage rate of bean (Phaseolus vulgaris L.) seeds during air-drying under different conditions of air, temperature and relative humidity, and to adjust several mathematical models to the empiric values observed, and select the one that best represents the phenomenon. Six mathematical models were adjusted to the experimental values to represent the phenomenon. It was determined the degree of adjustment of each model from the value of the coefficient of determination, the behavior of the distribution of the residuals, and the magnitude of the average relative and estimated errors. The rate of volumetric shrinkage that occurred in bean seeds during drying is between 25 and 37%. It basically depends on the final moisture content, regardless of the air conditions during drying. The Modified Bala & Woods' model best represented the process.Item Mathematical modeling of the drying process of corn ears(Acta Scientiarum. Agronomy, 2011-10) Corrêa, Paulo Cesar; Botelho, Fernando Mendes; Oliveira, Gabriel Henrique Horta; Goneli, André Luis Duarte; Resende, Osvaldo; Campos, Sílvia de CarvalhoThe objective of this work was to study and model the drying process of corn ears at different air temperatures. Thermodynamic properties associated with the drying process of this product were also determined. Corn ears with initial moisture content of 0.45 dry basis (kgw kgdm-1) were dried until they reached a final moisture content of 0.12 (kgw kgdm-1) at temperatures of 45, 55 and 65°C. Traditional models used to describe the drying process of several agricultural products were employed to fit the observed data of the drying process of corn ears. The effective diffusion coefficient (Def) was determined by means of an analytical solution of Fick's second law. It was concluded that the Logarithmic model was the one that best fit the observed data representing the drying process. Def values increased with temperature increases, ranging from 5.490 x 10-10 to 1.163 x 10-9 m2 s-1. Based on the dependence of the drying constant of the Logarithmic model with temperature, thermodynamic properties were determined, concluding that the drying kinetics variation is dependent on the energy contributions of the surrounding environment.