scholarly journals Determination of appropriate effective diffusivity for different food materials

2016 ◽  
Vol 35 (3) ◽  
pp. 335-346 ◽  
Author(s):  
M. I. H. Khan ◽  
Chandan Kumar ◽  
M. U. H. Joardder ◽  
M. A. Karim
Keyword(s):  
Effective Diffusivity

scholarly journals Mathematical Modeling and Determination of Effective Diffusivity of Mesquite during Convective Drying

2016 ◽  
Vol 07 (06) ◽  
pp. 814-823 ◽  
Author(s):  
Rennan Pereira de Gusmão ◽  
Thaisa Abrantes Souza Gusmão ◽  
Mário Eduardo Rangel ◽  
Moreira Cavalcanti-Mata ◽  
Maria Elita Martins Duarte
Keyword(s):  
Mathematical Modeling ◽  
Effective Diffusivity ◽  
Convective Drying

scholarly journals Drying kinetics of fermented grape pomace: Determination of moisture effective diffusivity

2016 ◽  
Vol 20 (8) ◽  
pp. 763-768 ◽  
Author(s):  
Kricelle M. Deamici ◽  
Lucas C. de Oliveira ◽  
Gabriela S. da Rosa ◽  
Elizangela G. de Oliveira
Keyword(s):  
Experimental Data ◽  
Effective Diffusivity ◽  
Drying Kinetics ◽  
Grape Pomace ◽  
Desorption Isotherms ◽  
Drying Curves ◽  
Gab Model ◽  
Kinetics Of ◽  
Moisture Effective Diffusivity

ABSTRACT The aim of this study was to obtain the equilibrium moisture content of grape (variety ‘Tannat’) pomace through desorption isotherms, to evaluate the drying kinetics, determine the coefficient of effective diffusivity and physico-chemically characterize the grape pomace and the product obtained after drying. The desorption isotherms were determined at 50, 60 and 70 ºC and the experimental data were fitted using the GAB model (Gugghenheim, Anderson and de Boer). Drying was evaluated using a 22 factorial experimental design with three center points and effective diffusivity was obtained through the diffusion model of Fick’s second law. The grape pomace was characterized regarding the contents of moisture, protein, carbohydrates, lipids, ash and dietary crude fiber. The obtained isotherms showed sigmoid shape and the experimental data fitted well to the GAB model. The drying curves showed only a decreasing rate period. The effective diffusivity values were within the range for organic materials. Dry grape pomace showed high contents of protein and fiber and can be used in the development of new products, in order to increase the nutritional content and add value to this byproduct.

Drying Kinetic Simulation of Clay Tiles Made from the Raw Material Having Less Clay Fraction

2014 ◽  
Vol 1036 ◽  
pp. 3-8
Author(s):  
Miloš Vasić ◽  
Zagorka Radojević
Keyword(s):  
Clay Fraction ◽  
Effective Diffusivity ◽  
Moisture Diffusivity ◽  
Effective Moisture Diffusivity ◽  
Diffusivity Coefficient ◽  
Moisture Movement ◽  
Effective Moisture ◽  
Drying Kinetic ◽  
Clay Tiles

In order to describe the internal moisture rate and to take all different mechanisms of moisture movement into account, it is suitable to use effective diffusivity as a measure of moisture rate, irrespectively of the mechanisms really involved. This means that all different mechanisms and driving forces for internal moisture transport are lumped together and introduced into effective moisture diffusivity. Hence, diffusion equations are retained and reused with the effective diffusivity coefficient as a measuring parameter of internal moisture ratio. In our previous studies we have presented the calculation method which assumed constant diffusivity. The next goal was to estimate effective diffusivity at various moisture contents, in a real case of non-linear drying curves, and to predict drying kinetic. In our last study we have developed a model for determination of the variable effective diffusivity and identification of the exact transition points between possible drying mechanisms. In this paper we have tried to develop more accurate tool for determination of time dependent effective moisture diffusivity. An analytical model and computing procedure were developed to evaluate mass transfer properties and describe drying kinetic of clay tiles having less clay fraction. The proposed procedure was validated with experimental drying data. Presented results have demonstrated that the proposed dying model can be applied for the accurate description of experimental drying kinetics and a reliable estimation of effective diffusivity.

scholarly journals Determination of thermophysical properties of cupuassu (Theobroma grandiflorum) dry almonds

2021 ◽  
Vol 7 (2) ◽  
Author(s):  
Elisa Santana Cunha ◽  
Geovana Pires Araújo Lima ◽  
Jorge Henrique Oliveira Sales ◽  
Elizama Aguiar de Oliveira
Keyword(s):  
Thermal Conductivity ◽  
Activation Energy ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Thermophysical Properties ◽  
Effective Diffusivity ◽  
Theobroma Grandiflorum

In comparison to cocoa, little has been reported on the drying of cupuassu almonds that can be used to produce cupulate, a chocolate type product. Thus, in this study thermophysical properties of cupuassu dry almonds (moisture = 9.68 % d.b.) were determined as: thermal conductivity (k) of 0.14 kW/(m.K), specific heat (cp) of 2.86 kJ/(kg.K), thermal diffusivity (?) of 4.8·10-5 m²/s, effective diffusivity (Deff) of 9.94·10-10 - 6.29·10-10 m²/s and activation energy (Ea) of 14.90 kJ/mol. These results showed a similarity of values between cupuassu and cocoa and allows to perform more specific studies for the development of dryers for the cupuassu almonds.

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