scholarly journals Mathematical models to describe the drying process of Moringa oleifera leaves in a convective-air dryer

2021 ◽  
Author(s):  
Kivaandra Dayaa Rao Ramarao ◽  
Zuliana Razali ◽  
Chandran Somasundram
Keyword(s):  
Activation Energy ◽  
Mathematical Models ◽  
Moringa Oleifera ◽  
Effective Diffusivity ◽  
Drying Process ◽  
Constant Rate ◽  
Rate Period ◽  
Moringa Oleifera Leaves ◽  
Air Dryer ◽  
Kinetics Of

Drying kinetics of Malaysian Moringa oleifera leaves was investigated using a convective-air dryer. The drying parameters were: temperature (40, 50, 60, 70 °C), air velocity (1.3 m s<sup>–1</sup>, 1.7 m s<sup>–1</sup>). The drying process took place in the falling rate period and there was an absence of a constant rate period in this experiment. Six mathematical models (Lewis, Henderson and Pabis, Wang and Singh, Peleg, Page, and logarithmic) were selected for the description of drying characteristics of the leaves. The Wang and Singh model was determined as the best model based on the highest overall coefficient determinant (R<sup>2</sup>) and the lowest overall root mean square error (RMSE). The effective diffusivity (D<sub>eff</sub><sub> </sub>) was also calculated which was in the range of 3.98 × 10<sup>–11</sup> m<sup>2</sup> s<sup>–1</sup> to 1.74 × 10<sup>–10</sup> m<sup>2</sup> s<sup>–1. </sup>An Arrhenius relation was constructed to determine the activation energy for the samples in the convective air dryer. The activation energy for M. oleifera leaves was 39.82 kJ mol<sup>–1</sup> and 33.13 kJ mol<sup>–1</sup> at drying velocities of 1.3 m s<sup>–1</sup> and 1.7 m s<sup>–1</sup>, respectively.

scholarly journals Drying Kinetics of Indigenous Fermented Foods of the Himalaya region (Gundruk, Sinki, and Maseura)

2021 ◽  
Vol 4 (2) ◽  
pp. 01-12
Author(s):  
Arjun Ghimire ◽  
Ashish Niroula ◽  
Prajwal Pokharel ◽  
Ranjana Poudel ◽  
Arjun Ghimire
Keyword(s):  
Activation Energy ◽  
Mathematical Models ◽  
Air Temperature ◽  
Effective Diffusivity ◽  
Moisture Loss ◽  
Fermented Foods ◽  
Drying Process ◽  
Statistical Parameters ◽  
Kinetics Of ◽  
The Himalaya

Indigenous fermented foods Gundruk (fermented mustard leaves), Sinki (fermented radish taproot), and Maseura (fermented lentils) are mostly sun dried, and thus often deteriorate during the uncontrolled drying process. Herein, cabinet drying was done at 50, 55, and 60°C after fermentation, and the moisture loss was systematically recorded. The data were converted to moisture ratio and fitted to five semi-theoretical drying mathematical models: Modified Henderson and Pabis, Logarithmic, Two-Term, Midilli et al., and Approximate diffusion. All the models were validated using statistical parameters, namely: R2, RMSE, χ2, and SSE. The Midilli et al. model gave excellent fit for all three products, with R2 greater than 0.97. The effective diffusivity values increased with an increase in air temperature for all the samples. The activation energy values were found to be 56.25, 21.63 and 15.08 kJ/ mol while the diffusivity constants were found to be 1268.51, 0.028, and 8.655× 10-3 m2/s for Gundruk, Sinki, and Maseura, respectively.

scholarly journals Drying Kinetics of Indigenous Fermented Foods of the Himalaya region (Gundruk, Sinki, and Maseura)

2021 ◽  
Vol 4 (2) ◽  
pp. 01-12
Author(s):  
Arjun Ghimire
Keyword(s):  
Activation Energy ◽  
Mathematical Models ◽  
Air Temperature ◽  
Effective Diffusivity ◽  
Moisture Loss ◽  
Fermented Foods ◽  
Drying Process ◽  
Statistical Parameters ◽  
Kinetics Of ◽  
The Himalaya

Indigenous fermented foods Gundruk (fermented mustard leaves), Sinki (fermented radish taproot), and Maseura (fermented lentils) are mostly sun dried, and thus often deteriorate during the uncontrolled drying process. Herein, cabinet drying was done at 50, 55, and 60°C after fermentation, and the moisture loss was systematically recorded. The data were converted to moisture ratio and fitted to five semi-theoretical drying mathematical models: Modified Henderson and Pabis, Logarithmic, Two-Term, Midilli et al., and Approximate diffusion. All the models were validated using statistical parameters, namely: R2, RMSE, χ2, and SSE. The Midilli et al. model gave excellent fit for all three products, with R2 greater than 0.97. The effective diffusivity values increased with an increase in air temperature for all the samples. The activation energy values were found to be 56.25, 21.63 and 15.08 kJ/ mol while the diffusivity constants were found to be 1268.51, 0.028, and 8.655× 10-3 m2/s for Gundruk, Sinki, and Maseura, respectively.

scholarly journals Cinética de secagem de vagens de algaroba (Prosopis juliflora SW)

2015 ◽  
Vol 10 (5) ◽  
pp. 115
Author(s):  
A. P. S. Nascimento ◽  
A. K. S. Lima ◽  
C. F. Cavalcanti ◽  
R. P. Gusmão
Keyword(s):  
Experimental Data ◽  
Thin Layer ◽  
Mathematical Models ◽  
Prosopis Juliflora ◽  
Drying Kinetics ◽  
Coefficient Of Determination ◽  
Fine Mesh ◽  
Rate Period ◽  
Air Dryer ◽  
Kinetics Of

<p>O objetivo deste trabalho foi estudar a cinética de secagem de vagens de algaroba em secador convectivo, nas temperaturas de 60, 70 e 80 °C. A secagem foi conduzida em camada fina, em um secador com circulação de ar, onde as vagens foram colocados em um recipiente de alumínio, medindo 20 mm de comprimento e 10 mm de largura, com capacidade de aproximadamente 10 g. Para representar o comportamento cinético da secagem foram utilizados os modelos matemáticos de Page, Henderson &amp; Pabis e Exponencial de Dois Termos. A partir dos resultados obtidos foi possível concluir que a secagem das vagens de algaroba ocorreu durante o período de taxa decrescente e é influenciada pela ação da temperatura, ou seja, ao aumentar a temperatura de secagem tem-se uma diminuição no tempo de estabilização, podendo este processo ser representado pelos três modelos matemáticos estudados, sendo o modelo Exponencial de Dois Termos o que melhor se ajustou aos dados experimentais apresentando coeficiente de determinação superior a 99,8% e desvios quadráticos médios menores que 0,05.</p><p align="center"><strong><em>Drying kinetics of pods of algaroba </em></strong><strong>(</strong><em>Prosopis juliflora<strong> SW</strong></em><strong>)<em></em></strong></p><p><strong>Abstract</strong><strong>: </strong>The objective of this work was to study the drying kinetics of algaroba pods in convective dryer at temperatures of 60, 70 and 80 °C<strong>.</strong> The drying was carried out in thin layer in a circulating air dryer where the beans were placed in a fine mesh metal container measuring 20 mm long and 10 mm wide, with a capacity of approximately 10 g. To represent the kinetics of drying the mathematical models of Page, Henderson and Pabis and Exponential of Two Terms were tested. Based on the results obtained it was concluded that the drying of algaroba pods occurs during falling rate period and is influenced by the action of temperature, in other words, by increasing the drying temperature has been a decrease in settling time, this process can be represented by the three mathematical models considered, being the Exponential of Two Terms model which best fits the experimental data showing higher coefficient of determination 98% and lower DQM. <strong></strong></p>

scholarly journals Effects of Osmotic Dehydration on the Hot Air Drying of Apricot Halves: Drying Kinetics, Mass Transfer, and Shrinkage

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 202
Author(s):  
Ivan Pavkov ◽  
Milivoj Radojčin ◽  
Zoran Stamenković ◽  
Krstan Kešelj ◽  
Urszula Tylewicz ◽  
...  
Keyword(s):  
Activation Energy ◽  
Osmotic Dehydration ◽  
Effective Diffusivity ◽  
Drying Process ◽  
Air Velocity ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Hot Air ◽  
Kinetics Of

This study aimed to determine the effects of osmotic dehydration on the kinetics of hot air drying of apricot halves under conditions that were similar to the industrial ones. The osmotic process was performed in a sucrose solution at 40 and 60 °C and concentrations of 50% and 65%. As expected increased temperatures and concentrations of the solution resulted in increased water loss, solid gain and shrinkage. The kinetics of osmotic dehydration were well described by the Peleg model. The effective diffusivity of water 5.50–7.387 × 10−9 m2/s and solute 8.315 × 10−10–1.113 × 10−9 m2/s was calculated for osmotic dehydration. Hot air drying was carried out at 40, 50, and 60 °C with air flow velocities of 1.0 m/s and 1.5 m/s. The drying time shortened with higher temperature and air velocity. The calculated effective diffusion of water was from 3.002 × 10−10 m2/s to 1.970 × 10−9 m2/s. The activation energy was sensitive to selected air temperatures, so greater air velocity resulted in greater activation energy: 46.379–51.514 kJ/mol, and with the osmotic pretreatment, it decreased to 35.216–46.469 kJ/mol. Osmotic dehydration reduced the effective diffusivity of water during the hot air drying process. It also resulted in smaller shrinkage of apricot halves in the hot air drying process.

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 &ordm;C 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&rsquo;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 &times; 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.

Effect of Pre-Treatment on the Drying Characteristics and Kinetics of Okra (Abelmoschus esculetus (L.) Moench) Slices

2009 ◽  
Vol 5 (2) ◽  
Author(s):  
Olajide Sobukola
Keyword(s):  
Air Temperature ◽  
Sample Thickness ◽  
Hot Water ◽  
Drying Rate ◽  
Diffusivity Coefficient ◽  
Drying Characteristics ◽  
Rate Period ◽  
Pretreatment Conditions ◽  
Air Dryer ◽  
Kinetics Of

The effects of air temperature (50, 60 and 70°C), sample thickness (2, 4 and 6mm) and pretreatment conditions (hot water blanching, 1 and 3% sodium metabisulphite solutions) on the drying characteristics and kinetics of okra were investigated using a convective hot air dryer at a flow rate of 1.5m/s. It was observed that pretreatment conditions, sample thickness and drying air temperature significantly (P<0.05) affected drying rate. Drying rate increases as temperature of drying air increases from 50 to 70°C. The drying curve for all experiments occurred in the falling rate period with no constant rate period. Three thin layer drying models (Page, modified Page I and Wang and Singh) were evaluated using coefficient of determination (R2), root mean square error (RMSE) and the reduced chi square (?2). The three models can appropriately describe the drying kinetics of okra slices considering the different experimental conditions. The effective diffusivity was determined using the Fick’s model and was observed to vary between 1.125x10-8 – 9.93x10-9m2/s and 1.165x10-8 – 7.131x10-9 m2/s for treated and untreated samples. The Arrhenius-type relationship describes the temperature dependence of diffusivity coefficient and was determined to be 16.749kJ/mol and 22.437kJ/mol for treated and untreated samples respectively.

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.

Prediction of Field Aging Gradient in Asphalt Pavements

2015 ◽  
Vol 2507 (1) ◽  
pp. 19-28 ◽  
Author(s):  
Xue Luo ◽  
Fan Gu ◽  
Robert L. Lytton
Keyword(s):  
Activation Energy ◽  
Prediction Model ◽  
Prediction Models ◽  
Fast Rate ◽  
Chemical Properties ◽  
Asphalt Pavements ◽  
Model Parameters ◽  
Void Content ◽  
Constant Rate ◽  
Rate Period

The aging of asphalt pavements is a key factor that influences pavement performance. Aging can be characterized by laboratory tests and prediction models. Common aging prediction models use the change of physical or chemical properties of asphalt binders based on regression techniques or aging reaction kinetics. The objective of this study was to develop a kinetics-based aging prediction model for the mixture modulus gradient in asphalt pavements to study long-term in-service aging. The proposed model was composed of three submodels for baseline modulus, surface modulus, and aging exponent to define the change of the mixture modulus with pavement depth. The model used kinetic parameters (aging activation energy and preexponential factor) of asphalt mixtures and combined the two reaction rate periods (fast-rate and constant-rate). Laboratory-measured modulus gradients of 29 field cores at different ages were used to determine the model parameters. The laboratory testing condition was converted to the field condition at a given age and corresponding temperature by introducing the rheological activation energy to quantify the temperature dependence of field cores at each age. The end of the fast-rate period or the beginning of the constant-rate period was accurately identified to model these two periods and to determine the associated parameters separately. The results showed that the predictions matched well with the measurements and the calculated model parameters were verified. The proposed aging prediction model took into account the major factors that affect field aging speed of an asphalt pavement, such as the binder type, aggregate type, air void content, pavement depth, aging temperature, and aging time.

Thin Layer Drying Process of Some Leafy Vegetables under Open Sun

2007 ◽  
Vol 13 (1) ◽  
pp. 35-40 ◽  
Author(s):  
O. P. Sobukola ◽  
O. U. Dairo ◽  
L. O. Sanni ◽  
A. V. Odunewu ◽  
B. O. Fafiolu
Keyword(s):  
Thin Layer ◽  
Effective Diffusivity ◽  
Thin Layers ◽  
Leafy Vegetables ◽  
Drying Process ◽  
Chi Square ◽  
Thin Layer Drying ◽  
Rate Period ◽  
Drying Models ◽  
Drying Curves

Open sun drying experiments in thin layers of crain-crain (CC), fever (FV) and bitter (BT) leaves grown in Abeokuta, Nigeria were conducted. The drying process took place in the falling rate period and no constant rate period was observed from the drying curves. Eight thin layer mathematical drying models were compared using the multiple determination coefficients (R2), reduced chi-square (χ2) and root mean square error (RMSE) between the observed and predicted moisture ratios. Accordingly, Midilli et al. model satisfactorily described the drying curves of the three leaves with R2 of 0.9980, χ2 of 2.0×10-4 and RMSE of 1.09×10-2 for CC leaves; R2 of 0.9999, χ2 of 2×10-6 and RMSE of 1.11×10-3 for FV leaves; and R2 of 0.9998, χ2 of 1.9×10-5 and RMSE of 3.3×10-3 for BT leaves. The effective diffusivity was found to be 52.91×10-10, 48.72×10-10 and 43.42×10-10 m2/s for CC, BT and FV leaves, respectively.

Effect of Air Velocity and Temperature on the Drying Kinetics of Drumstick Leaves (Moringa Oleifera)

2012 ◽  
Vol 8 (4) ◽  
Author(s):  
Monica Premi ◽  
Harish Sharma ◽  
Ashutosh Upadhyay
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Moringa Oleifera ◽  
Moisture Diffusivity ◽  
Drying Kinetics ◽  
Drying Rate ◽  
Air Velocity ◽  
Drying Time ◽  
Effective Moisture ◽  
Kinetics Of

Abstract The present study examines the effect of air velocity on drying kinetics of the drumstick leaves in a forced convective dryer. The drumstick leaves were dried in the temperature range of 50–800 C, at different air velocity (Dv) of 0.5 and 1.3 m/s. The results indicated that drying temperature and air velocity are the factors in controlling the drying rate. Experimental data obtained for the samples for color, drying rate and drying time proved that air velocity of 1.3 m/s yielded the product superior in terms of both quality and energy efficiency as compared to the samples at 0.5 m/s. Activation energy for drumstick leaves dried with air velocity, 0.5 and 1.3 m/s was 12.50 and 32.74 kJ/mol respectively. The activation energy relates similarly with the effective moisture diffusivity which also increased with increase in air velocity and temperature.

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