scholarly journals Drying kinetics of crushed mass of ‘jambu’: Effective diffusivity and activation energy

2018 ◽  
Vol 22 (7) ◽  
pp. 499-505 ◽  
Author(s):  
Francileni P. Gomes ◽  
Resende Osvaldo ◽  
Elisabete P. Sousa ◽  
Daneil E. C. de Oliveira ◽  
Francisco R. de Araújo Neto
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Agricultural Research ◽  
Effective Diffusion ◽  
Effective Diffusivity ◽  
Information Criterion ◽  
Drying Kinetics ◽  
Coefficient Of Determination ◽  
Chi Square ◽  
Chi Square Test

ABSTRACT The aim of this paper was to analyze the drying kinetics, test the Akaike information criterion (AIC) and Schwarz’s Bayesian information criterion (BIC) in the selection of models, determine the effective diffusivity and activation energy of the crushed mass of ‘jambu’ leaves for different conditions of temperature and layer thicknesses. The experiment was carried out at the Food Laboratory of the Brazilian Agricultural Research Corporation (Embrapa) in Macapá-AP. Drying was carried out in air circulation oven with speed of 1.0 m s-1 at various temperatures (60, 70 and 80 ºC) and layer thicknesses (0.005 and 0.010 m). The experimental data were fitted to 11 mathematical models. Coefficient of determination (R2), mean relative error (P), mean estimated error (SE), Chi-square test (χ2), AIC and BIC were the selection criteria for the models. For the effective diffusivity, the Fick’s diffusion model was used considering the flat plate geometry. It was found that Midilli and Logarithmic models showed the best fit to the experimental data of drying kinetics. Effective diffusion coefficient increases with increment in the thickness of the material and with the temperature elevation. Activation energy of the material was of 16.61 kJ mol-1 for the thickness of 0.005 m, and 16.97 kJ mol-1 for the thickness of 0.010 m. AIC and BIC can be additionally included to select models of drying.

scholarly journals Drying kinetics of ‘gueroba’ (Syagrus oleracea) fruit pulp

2021 ◽  
Vol 25 (1) ◽  
pp. 23-29
Author(s):  
Ana P. P. Jorge ◽  
Weder N. Ferreira Junior ◽  
Lígia C. de M. Silva ◽  
Daniel E. C. de Oliveira ◽  
Osvaldo Resende
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Effective Diffusion ◽  
Drying Kinetics ◽  
Coefficient Of Determination ◽  
Chi Square ◽  
Adequate Model ◽  
Nonlinear Regression Models ◽  
Water Diffusivity ◽  
Chi Square Test

ABSTRACT The ‘Gueroba’ fruit can be used to produce flours with potential for the development of new products from the ‘Cerrado’ socio-biodiversity. The objective was to estimate the drying kinetics and determine the effective diffusion coefficient and activation energy for the pulp of ‘gueroba’ fruits subjected to different drying temperatures. ‘Gueroba’ fruits were manually pulped, removing the mesocarp with the epicarp, and this material was identified as the pulp. The material was subjected to oven drying at temperatures of 40, 50, 60 and 70 °C. Nonlinear regression models were fitted to the experimental data. The most adequate model was selected through the coefficient of determination, mean relative and estimated errors, Chi-square test, AIC and BIC. As the drying temperature increases, the processing time to achieve the same moisture content decreases, due to the increase in water diffusivity inside the product. The Midilli model showed the best fit to the experimental data obtained. The effective diffusion coefficients of the pulp of ‘gueroba’ fruits showed magnitudes between 3.11 x 10-9 to 5.84 x 10-9 m2 s-1 for temperatures from 40 to 70 °C. The activation energy of the process was 18.34 kJ mol-1.

scholarly journals Drying Kinetics of Noni Seeds

2019 ◽  
Vol 11 (5) ◽  
pp. 250 ◽  
Author(s):  
Wellytton Darci Quequeto ◽  
Osvaldo Resende ◽  
Patrícia Cardoso Silva ◽  
Fábio Adriano Santos e Silva ◽  
Lígia Campos de Moura Silva
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Diffusion Coefficient ◽  
Moisture Content ◽  
Mathematical Models ◽  
Effective Diffusion Coefficient ◽  
Effective Diffusion ◽  
Information Criterion ◽  
Drying Kinetics ◽  
Kinetics Of

Noni seeds have been used for years as an important medicinal source, with wide use in the pharmaceutical and food industry. Drying is a fundamental process in the post-harvest stages, where it enables the safe storage of the product. Therefore, the present study aimed to fit different mathematical models to experimental data of drying kinetics of noni seeds, determine the effective diffusion coefficient and obtain the activation energy for the process during drying under different conditions of air temperature. The experiment used noni seeds with initial moisture content of 0.46 (decimal, d.b.) and dehydrated up to equilibrium moisture content. Drying was conducted under different controlled conditions of temperature, 40; 50; 60; 70 and 80 ºC and relative humidity, 24.4; 16.0; 9.9; 5.7 and 3.3%, respectively. Eleven mathematical models were fitted to the experimental data. The parameters to evaluate the fitting of the mathematical models were mean relative error (P), mean estimated error (SE), coefficient of determination (R2), Chi-square test (c2), Akaike Information Criterion (AIC) and Schwarz’s Bayesian Information Criterion (BIC). Considering the fitting criteria, the model Two Terms was selected to describe the drying kinetics of noni seeds. Effective diffusion coefficient ranged from 8.70 to 23.71 × 10-10 m2 s-1 and its relationship with drying temperature can be described by the Arrhenius equation. The activation energy for noni seeds drying was 24.20 kJ mol-1 for the studied temperature range.

scholarly journals Drying kinetics of baru flours as function of temperature

2018 ◽  
Vol 22 (10) ◽  
pp. 713-719 ◽  
Author(s):  
Douglas R. Reis ◽  
Fabrício B. Brum ◽  
Eduardo J. O. Soares ◽  
Jessiana R. Magalhães ◽  
Fabrício S. Silva ◽  
...  
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Food Industry ◽  
Nutritional Value ◽  
Effective Diffusivity ◽  
Drying Kinetics ◽  
Statistical Parameters ◽  
Noticeable Effect ◽  
Different Temperatures ◽  
Kinetics Of

ABSTRACT Several types of seeds have been initially used in the food industry due to the great potential that vegetable proteins have. Baru is a fruit commonly found in the Cerrado biome, having a high nutritional value. This paper aimed to determine and analyze the drying kinetics of whole and defatted baru almond flours at different temperatures. The flour resulting from almond milling was defatted using petroleum ether. The drying processes were performed at temperatures of 40, 50 and 60 ºC. The mathematical models of Page, Henderson and Pabis, Midilli & Kucuk, Thompson and Approximation of Diffusion were fitted to the experimental data. The results showed a noticeable effect of air temperature on the drying kinetics of whole and defatted baru almond flours. According to the statistical parameters of analysis, the models Midilli & Kucuk and Page were the ones with the best fits to the experimental data. The effective diffusivity values found ranged from 8.02 × 10–10 to 19.90 × 10–10 m2 s-1 and for the activation energy were 22.39 and 39.37 KJ mol-1 for whole and defatted almonds, respectively.

scholarly journals Thin Layer Drying Kinetics Modelling of Curry Leaves (Murraya koenigii L.) in Cabinet Dryer

2018 ◽  
Vol 2 ◽  
pp. 53-58
Author(s):  
Arjun Ghimire ◽  
Nirajan Magar
Keyword(s):  
Experimental Data ◽  
Thin Layer ◽  
Effective Diffusivity ◽  
Coefficient Of Determination ◽  
Murraya Koenigii ◽  
Small Tree ◽  
Chi Square ◽  
Kinetics Modelling ◽  
Curry Leaves ◽  
Thin Layer Drying

Curry leaves (Murraya koenigii L.) are the sweet smelling leaves of small tree of Rutaceae family native to Southwest Asia. In this study, the effect of temperatures (50, 55 and 60°C) on the drying of curry leaves was investigated. The experimental data were fitted to six thin layer mathematical models (Newton, Page, Handerson and Pabis, logarithmic, two-term exponential and Midilli et al). The models were evaluated in terms of coefficient of determination (R2), chi square (χ2) and root mean square error (RMSE). The Midilli et al model was best fitted to the experimental data of all the models evaluated. The effective diffusivity was calculated using Fick's diffusion equation, and the value varied from 2.07×10-12 m2/s to 2.643×10-12 m2/s. The activation energy and the diffusivity constant were found to be 21.808 kJ/mol and 4.667×10-8 m2/s respectively.

scholarly journals Mathematical modeling of the foam-mat drying curves of guava pulp

2017 ◽  
Vol 21 (10) ◽  
pp. 721-725 ◽  
Author(s):  
Roberta M. G. Maciel ◽  
Marcos R. A. Afonso ◽  
José M. C. da Costa ◽  
Leandro S. Severo ◽  
Natália D. de Lima
Keyword(s):  
Experimental Data ◽  
Coefficient Of Determination ◽  
Drying Rate ◽  
Albumin Concentration ◽  
Mean Square ◽  
Liquid Food ◽  
Chi Square ◽  
Foaming Agent ◽  
Chi Square Test ◽  
Drying Curves

ABSTRACT In foam-mat drying, the liquid food is foamed by the addition of a foaming agent, for example, albumin. The aim of this study was to evaluate the adjustment of mathematical models to foam mat drying curves of guava pulp. The fits were evaluated using samples with 4 and 8% albumin (m m-1) and drying temperatures of 75, 80 and 85 °C. The samples were placed on aluminum trays. Drying was carried out in a tray dryer. The Lewis, Page, Midilli and Logarithmic models were fitted to the experimental data and evaluated based on the coefficient of determination (R2), root-mean-square error (RMSE) and chi-square test. All models fitted well to experimental data and Midilli was the best. Albumin concentration and temperature influenced the drying rate; the lowest drying times occurred for the highest albumin concentration and highest drying temperature.

scholarly journals Kinetics and thermodynamic properties related to the drying of 'Cabacinha' pepper fruits

2016 ◽  
Vol 20 (2) ◽  
pp. 174-180 ◽  
Author(s):  
Hellismar W. da Silva ◽  
Renato S. Rodovalho ◽  
Marya F. Velasco ◽  
Camila F. Silva ◽  
Luís S. R. Vale
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Free Energy ◽  
Thermodynamic Properties ◽  
Gibbs Free Energy ◽  
Removal Rate ◽  
Effective Diffusion ◽  
Drying Time ◽  
Three Samples ◽  
Different Temperatures

ABSTRACT The objective of this study was to determine and model the drying kinetics of 'Cabacinha' pepper fruits at different temperatures of the drying air, as well as obtain the thermodynamic properties involved in the drying process of the product. Drying was carried out under controlled conductions of temperature (60, 70, 80, 90 and 100 °C) using three samples of 130 g of fruit, which were weighed periodically until constant mass. The experimental data were adjusted to different mathematical models often used in the representation of fruit drying. Effective diffusion coefficients, calculated from the mathematical model of liquid diffusion, were used to obtain activation energy, enthalpy, entropy and Gibbs free energy. The Midilli model showed the best fit to the experimental data of drying of 'Cabacinha' pepper fruits. The increase in drying temperature promoted an increase in water removal rate, effective diffusion coefficient and Gibbs free energy, besides a reduction in fruit drying time and in the values of entropy and enthalpy. The activation energy for the drying of pepper fruits was 36.09 kJ mol-1.

scholarly journals Mathematical modeling of pequi pulp drying and effective diffusivity determination

2017 ◽  
Vol 21 (7) ◽  
pp. 493-498 ◽  
Author(s):  
Elisabete P. de Sousa ◽  
Rossana M. F. de Figueirêdo ◽  
Josivanda P. Gomes ◽  
Alexandre J. de M. Queiroz ◽  
Deise S. de Castro ◽  
...  
Keyword(s):  
Experimental Data ◽  
Effective Diffusivity ◽  
Drying Kinetics ◽  
Convective Drying ◽  
Drying Time ◽  
Air Speed ◽  
Drying Curves ◽  
Increasing Temperature ◽  
Kinetics Of ◽  
Best Fit

ABSTRACT The aim of this work was to study the drying kinetics of pequi pulp by convective drying at different conditions of temperature (50, 60, 70 and 80 °C) and thickness (0.5, 1.0 and 1.5 cm) at the air speed of 1.0 m s-1, with no addition of adjuvant. The experimental data of pequi pulp drying kinetics were used to plot drying curves and fitted to the models: Midilli, Page, Henderson & Pabis and Newton. Effective diffusivity was calculated using the Fick’s diffusion model for a flat plate. It was found that, with increasing thickness, the drying time increased and, with increasing temperature, the drying time was reduced. The Midilli model showed the best fit to the experimental data of pequi pulp drying at all temperatures and thicknesses, presenting higher coefficients of determination (R2), indicating that this model satisfactorily represents the pequi pulp drying phenomenon. There was a trend of increase in the effective diffusivity with the increase in pulp layer thickness and temperature.

scholarly journals Methods and techniques of research motivation and satisfaction of employees

2021 ◽  
Vol 9 (2) ◽  
pp. 53-63
Author(s):  
Dragana Pešić-Jenačković
Keyword(s):  
Analysis Of Variance ◽  
Employee Motivation ◽  
Test Point ◽  
Coefficient Of Determination ◽  
Business Success ◽  
Chi Square ◽  
Methods And Techniques ◽  
Chi Square Test ◽  
Using Data ◽  
The Impact

Motivation and employee satisfaction are very important precondition for the effectiveness of work and the achievement of set goals for individuals and organizations. Consequently, continuous measurement of employee motivation and satisfaction is essential to improve company's efficiency and improve human resource use. The results of a well-planned, detailed and adequate methods and techniques of research on employee motivation and satisfaction can be applied to the design of various schemes in order to reduce absenteeism and employee turnover and overall business success. In this paper, the emphasis is on the methodology of researching employee motivation and satisfaction. In addition to the elaboration of questionnaires with scales for measuring the motivation and satisfaction of employees, it is explained in which situations, in which types of questions and answers, respectively, types of data, and how certain statistical techniques are applied, such as: T-test, One-factor analysis of variance (ANOVA), Chi-square test, Point-two-series correlations. Also, the importance of using the subsequent post hoc test (LSD comparison) in the analysis of variance, as well as the indicators of correlation, the strength of the impact, such as: phi correlation coefficient, Kramer's coefficient and contingency coefficient, is pointed out in the Chi-square test. In addition to the mentioned techniques and indicators from SPSS, the role of certain indicators (eta squared and coefficient of determination) is calculated, which are calculated using data from research results and with the help of certain formulas

scholarly journals Enhanced sorption capacity of the metal-dye system from water effluents by using polish activated industrial waste

2020 ◽  
Author(s):  
Eleonora Sočo ◽  
Jan Kalembkiewicz
Keyword(s):  
Coal Fly Ash ◽  
Sorption Process ◽  
Sorption Kinetics ◽  
Coefficient Of Determination ◽  
Isotherm Models ◽  
Particle Model ◽  
Particle Diffusion ◽  
Hexadecyltrimethylammonium Bromide ◽  
Chi Square ◽  
Chi Square Test

Abstract The activated coal fly ash (FA) treated with NaOH and hexadecyltrimethylammonium bromide (HDTMABr) was used as adsorbent for removal of cadmium(II) ions and rhodamine B (RB) form an aqueous solution. Characterization of FA and FA-HDTMABr were done by using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The sorption equilibrium in the system were analysed by isotherm models, such as Freundlich, Langmuir, generalized Langmiur-Freundlich, Redlich-Peterson, Jovanović, extended Jovanović, Tóth, Fumkin-Fowler-Guggenheim, Fowler-Guggenheim-Jovanović-Freundlich, Temkin, Dubinin-Radushkevich, Halsey, Brunauer Emmett and Teller. The evaluation of fitting of the isotherms studied experimentally points was carried out by means of the reduced chi-square test and the coefficient of determination. The maximum monolayer adsorption capacity of the FA-HDTMABr was found to be 744 mg·g−1 and 666 mg·g−1 for Cd(II) and RB, respectively. The PFO, PSO, Elovich mass transfer, liquid film diffusion and intra-particle diffusion models were analysed. Sorption kinetics data were well fitted by PSO model. The Elovich and intra-particle model also revealed that there are two separate stages in the sorption process, namely, the external diffusion and the inter-particle diffusion.

scholarly journals Effect of temperature on the physical changes and drying kinetics in plum (Prunus domestica L.) Pozegaca variety

2011 ◽  
Vol 17 (3) ◽  
pp. 283-289 ◽  
Author(s):  
Milovan Zivkovic ◽  
Sveto Rakic ◽  
Radojka Maletic ◽  
Dragan Povrenovic ◽  
Milos Nikolic ◽  
...  
Keyword(s):  
Effective Diffusivity ◽  
Absolute Error ◽  
Drying Kinetics ◽  
Effect Of Temperature ◽  
Coefficient Of Determination ◽  
Maximum Absolute Error ◽  
Nonlinear Regression Models ◽  
Regression Error ◽  
Physical Changes ◽  
Model Correlation

In this study, drying kinetics of autochthonous variety Pozegaca plum was examined in a laboratory dryer at three temperatures. The whole plum fruits, together with the kernels were subjected to the drying process. The effect of drying has been examined at temperatures 55, 60 and 75?C, with a constant air velocity of 1.1 m s-1. The corresponding experimental results were tested using six nonlinear regression models. Coefficient of determination (R2), standard regression error (SSE), model correlation coeficient (Vy), as well as the maximum absolute error (?Y) showed that logaritmic model was in good agreement with the experimental data obtained. During drying of plums, the effective diffusivity was found to be between 5.6?10-9 for 55?C and 8.9?10-9 m2 s-1 at 75?C, respectively. The physical characteristics of the fresh (lenght 39.64 mm and width 29.15 mm) and dried (lenght 37.52 mm and width 22.85 mm) plum fruit were determined. Finally, by chemical analysis, the content of micro-and macro41 elements (Fe, Mn, Cu, B and N, F, K, Ca, Mg, S) in the skin and flesh of the dried product, prunes, has been established.

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