scholarly journals Drying kinetics of bananas by natural convection: Influence of temperature, shape, blanching and cultivar

2011 ◽  
Vol 35 (2) ◽  
pp. 368-376 ◽  
Author(s):  
Soraia Vilela Borges ◽  
Maurício C. Mancini ◽  
Jefferson Luiz Gomes Corrêa ◽  
Julia Benedito Leite
Keyword(s):  
Natural Convection ◽  
Exponential Model ◽  
Positive Influence ◽  
Drying Rate ◽  
Cylindrical Shape ◽  
Sample Shape ◽  
Drying Behavior ◽  
Drying Rates ◽  
Kinetics Of ◽  
Good Agreement

The influence of variables as temperature, solid shape, temperature, branching and cultivar on drying of bananas were studied. Bananas from cv. Prata and D'água, on disk and cylindrical shape, blanched or not, were dehydrated in a tray dryer in natural convection at 40 and 70ºC. Drying behavior was analyzed by using a mathematical model. The exponential model showed good agreement to experimental data (r² 0.93 - 0.99 and standard error: 0.01- 0.05). Temperature presented positive influence on drying rate in all the tested conditions. With respect to the sample shape, the disk shape carried out to significantly higher drying rates only for D'água cultivar without blanching. Blanching was significantly influent, with positive influence, on drying rate of banana cv. Prata at 40º C. The influence of the cultivar did not present a defined tendency.

scholarly journals Natural convection drying kinetics of ‘Prata’ and ‘D’água’ banana cultivars (Musa ssp) by nonlinear regression models

2019 ◽  
Vol 41 (5) ◽  
Author(s):  
Thais Destefani Ribeiro Furtado ◽  
Joel Augusto Muniz ◽  
Edilson Marcelino Silva ◽  
Ariana Campos Frühauf ◽  
Tales Jesus Fernandes
Keyword(s):  
Natural Convection ◽  
Regression Models ◽  
Information Criteria ◽  
Drying Kinetics ◽  
Moisture Loss ◽  
Drying Rate ◽  
Nonlinear Regression Models ◽  
The World ◽  
Drying Rates ◽  
Kinetics Of

Abstract Banana is among fruits most planted in tropical countries and belongs to the fruit group most consumed in the world; however, banana needs proper conservation techniques. The aim of this study was to describe the drying kinetics of ‘Prata’ and ‘D’água’ banana cultivars at temperatures of 40 and 70°C, comparing the Henderson, STPE, Lewis, Page and Fick regression models, estimating the Absolute Drying Rate (ADR). Parameters were estimated with R and SAS Studio softwares, using for comparison and selection models of the R²aj, RSD and corrected Akaike Information Criteria. The Page and Fick models did not adjust, and the others presented good adjustment to data. The Henderson model was the most suitable to describe data of ‘Prata’ banana at both temperatures and ‘D’água’ banana at 70°C and Lewis at 40°C for this cultivar. The drying rate of ‘Prata’ banana at temperatures of 40 and 70°C were 0.00079 g of water/ min and 0.00400 g of water/min respectively and for ‘D’água’ banana, drying rates were 0.00111 g of water/min. and 0.00495 g of water/min., respectively. Using ADR, it was observed that in one third of the drying period, there was 70% of moisture loss at 70°C.

Conversion of Alkoxide Solutions to Oxides: Evaporation of Products

1989 ◽  
Vol 155 ◽  
Author(s):  
R. A. Lipeles ◽  
D. J. Coleman
Keyword(s):  
High Flow ◽  
Drying Rate ◽  
Flow Rates ◽  
Long Time ◽  
Drying Rates ◽  
Drying Conditions ◽  
Kinetics Of ◽  
By Products ◽  
Evaporation Kinetics ◽  
Kinetics Monitoring

ABSTRACTThe evaporation of organic by-products released during drying of 1-mm thick silicon tetramethoxide gels was analyzed using gas chromatography. The evaporation kinetics of methanol depended on the drying rate achieved by flowing dry air over the gel. For drying at flow rates less than 50 cm 3/min, exponential kinetics were observed initially with a long time constant (about 100- to 400-min). For drying rates greater than 70 cm3/min, diffusional (t−1/2) kinetics were observed initially. Cracking of the gel during drying was used to indicate the degree of stress. At low drying rates, minor cracking was observed near the edges of the gel. At high flow rates, extensive cracking was observed in samples that exhibited early t−1/2 kinetics. Monitoring the kinetics of drying is essential to optimizing the drying conditions to minimize stress and cracking in gels.

Effect of Relative Humidity on Drying Kinetics of Agricultural Products

2014 ◽  
Vol 699 ◽  
pp. 257-262
Author(s):  
Sulastri Sabudin ◽  
Mohd Zairul Hakimi Remlee ◽  
Mohd Faizal Mohideen Batcha
Keyword(s):  
Relative Humidity ◽  
Air Temperature ◽  
Energy Efficient ◽  
Human Population ◽  
Room Temperature ◽  
Food Preservation ◽  
Agricultural Products ◽  
Drying Behavior ◽  
Drying Rates ◽  
Kinetics Of

The demand for food has been ever increasing in proportion with the growing human population. This includes agricultural products including fruits. Hence, food preservation for extended usage through drying is gaining importance. This study reports the drying behavior of several agricultural products, namely sweet potato, carrot, ginger, turmeric, passion fruit and its rind. Focus has been given to the effect of relative humidity on drying for these products at room temperature. Experiments were carried out at 27°C by varying relative humidity at 40%, 60% and 80%. It was found that the relative humidity has a strong effect on drying, with lower relative humidity providing higher drying rates. In humid surrounding like Malaysia which has an average humidity more than 70%, controlling humidity of drying air may result in an energy efficient process in comparison to raising the drying air temperature

scholarly journals Effect of blanching methods on drying kinetics of bell pepper

2011 ◽  
Vol 11 (48) ◽  
pp. 5457-5474
Author(s):  
Toyosi Tunde - Akintunde ◽  
◽  
BO Akintunde ◽  
A Fagbeja ◽  
◽  
...  
Keyword(s):  
Palm Oil ◽  
Water Movement ◽  
Drying Kinetics ◽  
Bell Pepper ◽  
Drying Rate ◽  
Drying Process ◽  
Oil Water ◽  
Drying Rates ◽  
Kinetics Of

Various blanching methods and drying temperatures were applied to bell pepper (Capiscum annum) to investigate the effect on its drying characteristics. Pepper (Capiscum annum) is an abundant and cheap source of vitamins, minerals and fibre. However, its high moisture content makes it susceptible to deterioration. The most common method of preservation is drying but the dried products obtained are of reduced nutritional qualities. Pretreatment of pepper before drying improves the quality of the dried pepper and increases its drying rate. Steam and water blanching as a form of pretreatment has been reported to increase drying rate and improve the quality of dried products but there is not much information on other types of oil/water blanching methods. The effect of blanching (steam, water, palm oil/water and groundnut oil/water) as a pretreatment on the drying kinetics of bell pepper dried at temperatures of 50, 60, 70, 80 and 90o C, was studied. Drying of raw untreated bell pepper was taken as a control. The results indicate that water removal at the initial stage of the drying process was highest and there was a rapid decrease as drying continued until equilibrium was reached at the end of process. The blanched samples generally had higher drying rates (at p<0.05) than the untreated samples. The values for the drying rate for steam and water blanched samples were higher (but not at p<0.05) than the drying rates for samples blanched in oil/water mixtures. The drying rate as well as effective moisture diffusivity, Deff, increased with increasing drying temperature. Values of Deff varied from 3.55 x 10-9 m 2/s to 2.34 x 10-9 m 2/s with the highest being SB (steam blanched) at 80oC and the lowest UB (unblanched) at 50oC. The drying process took place mainly in the falling rate period. The activation energies varied from 39.59 to 83.87 kJ/mol, with PB (palm oil/water blanched) samples having the lowest and UB having the highest Ea value. The lower values for pretreated samples imply that water movement from the internal regions is faster in pretreated samples. This suggests that blanching as a method of pretreatment generally increases water diffusion.

scholarly journals THE EFFECT OF MICROWAVE OUTPUT POWER ON DRYING KINETICS OF YOGHURT AND MATHEMATICAL MODELING OF DRYING CURVES

2021 ◽  
Vol 51 (2) ◽  
pp. 127-131
Author(s):  
Ayşe Nur Yüksel
Keyword(s):  
Effective Diffusivity ◽  
Microwave Oven ◽  
Drying Kinetics ◽  
Layer Model ◽  
Domestic Microwave Oven ◽  
Drying Behavior ◽  
Drying Rates ◽  
Drying Curves ◽  
Kinetics Of

The objectives of this study were investigation the effects of microwave output powers on drying kinetics of yoghurt, selecting the best fitted thin-layer model to characterize the drying behavior of yoghurt and determination of the activation energy and effective diffusivity. In order to achieve these objectives, low-fat yoghurt was dried by using domestic microwave oven at different microwave output powers (100, 180 and 300 W). Average drying rates were determined as 1.49, 4.43 and 7.90 g H2O m-2 s-1 for microwave output powers of 100, 180 and 300 W, respectively. The effective moisture diffusivities were determined as 3.30 x 10-9, 6.62 x 10-9 and 1.15 x 10-8 m2 s-1 for 100, 180 and 300 W, respectively. The Ea of yoghurt was found as 3.62 W g-1. Midilli and others model was selected as best fitted model due to highest values of R2 and low values of χ2, RMSE and RSS.

scholarly journals Drying kinetics and effective diffusion of watermelon seeds

2020 ◽  
Vol 9 (4) ◽  
pp. e16942887
Author(s):  
Valdiney Cambuy Siqueira ◽  
Geraldo Acacio Mabasso ◽  
Wellytton Darci Quequeto ◽  
Caroline Ramos Da Silva ◽  
Elton Aparecido Siqueira Martins ◽  
...  
Keyword(s):  
Activation Energy ◽  
Citrullus Lanatus ◽  
Linear Regression Analysis ◽  
Effective Diffusion ◽  
Drying Kinetics ◽  
Air Velocity ◽  
Different Temperatures ◽  
Drying Behavior ◽  
Drying Rates ◽  
Kinetics Of

Studying the drying kinetics allows describing the process by mathematical models and obtaining information that helps to understand the phenomenon in question. Considering that watermelon (Citrullus lanatus) seeds have high moisture content and need to be subjected to drying, the objective was to select the model that best represents the drying behavior of watermelon seeds and determine the diffusion coefficient, activation energy and drying rate of these seeds at different temperatures. The seeds were dried in an experimental dryer at temperatures of 40, 45, 50, 55 and 60 °C, with air velocity of 0.8 m s-1, in four replicates. The models were fitted with non-linear regression analysis using the Gauss-Newton method. It was concluded that the models that best represent the drying kinetics of watermelon seeds are Approximation of Diffusion for temperatures of 40, 50 and 55 °C and Page for 55 and 60 °C. The highest drying rates are observed at the highest temperatures. The diffusion coefficients presented magnitude of 7.69684×10-10 and 1.27585×10-9 for the range from 40 to 60 °C, and the activation energy was 12.2641 kJ mol-1.

Modelling of the Drying Kinetics of Opuntia Ficus Indica Fruits and Cladodes

2010 ◽  
Vol 6 (2) ◽  
Author(s):  
Amira Touil ◽  
Saber Chemkhi ◽  
Fethi Zagrouba
Keyword(s):  
Prickly Pear ◽  
Drying Rate ◽  
Pear Fruit ◽  
Opuntia Ficus Indica ◽  
Rate Period ◽  
Different Temperatures ◽  
Drying Rates ◽  
Drying Behaviour ◽  
Drying Curves ◽  
Kinetics Of

The effect of the drying rates of fruit and cladode of Opuntia Ficus Indica was examined at different temperatures. The experimental drying curves show only a falling drying rate period. The values of drying rate of prickly pear (fruit and cladode) almost doubled when the drying temperature was increased from 40 to 60°C. The experimental drying data were applied to various drying equation (Logarithmic; Wang and Singh, Henderson and Pabis, MMF model and Midilli equation). Midilli equation was optimal for characterizing drying behaviour of prickly pear for the whole range of temperature with a correlation coefficient of 99.99% for the fruit and the cladode and a standard error of 0.0015 for the fruit and 0.0017 for the cladode.

Effects of Drying Parameters on the Drying Kinetics of Fermented Ground Cassava Using a Rotary Dryer

2010 ◽  
Vol 6 (6) ◽  
Author(s):  
Ademiluyi Falilat Taiwo ◽  
M. F. N. Abowei ◽  
Y. T. Puyate ◽  
S. C. Achinewhu
Keyword(s):  
Air Temperature ◽  
Drying Kinetics ◽  
High Mass ◽  
Drying Rate ◽  
Air Velocity ◽  
Feed Drive ◽  
Rotary Dryer ◽  
Drive Speed ◽  
Kinetics Of ◽  
Good Agreement

The effects of drying parameters on the drying kinetics of fermented ground cassava were studied. Fermented ground cassava (TMS 30572) was dried in a bench scale rotary dryer at different inlet air temperature (115-230°C), inlet air velocity (0.83-1.55 m/s), feed drive speed (12-100 rpm), drum drive speed (8-18 rpm), relative humidity of inlet air (50 to 80 percent), and mass of feed (50-500 g). It is shown that inlet air temperature and inlet air velocity have the most significant effects on the drying rate of fermented ground cassava. A model which predicts the drying rate of fermented ground cassava as function of inlet air temperature and inlet air velocity is presented. Predictions of the model are compared with experimental data, and good agreement is obtained. For proper gelatinization of fermented cassava mash, the inlet air temperature should be within the range 140-230°C, low inlet air velocity (< 1.55 m/s), low drum drive speed (8-12 rpm), moderate air humidity (50 to 65 percent), and low feed drive speed of about 12 rpm. For high mass of feed (> 500 g), inlet air temperature in the range 190-230°C is recommended for proper gelatinization of fermented cassava.

Diffusion model for deposition of epitaxial GaAs layers prepared by the MOCVD method

1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Kinetic Model ◽  
Gas Phase ◽  
Substrate Surface ◽  
Deposition Process ◽  
Hydrogen Atmosphere ◽  
Epitaxial Gaas ◽  
Kinetics Of ◽  
Good Agreement

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.

scholarly journals The Effect of Al on the Formation of a CrTaO4 Layer in Refractory High Entropy Alloys Ta-Mo-Cr-Ti-xAl

2021 ◽  
Author(s):  
S. Schellert ◽  
B. Gorr ◽  
H.- J. Christ ◽  
C. Pritzel ◽  
S. Laube ◽  
...  
Keyword(s):  
Mass Gain ◽  
Positive Influence ◽  
High Entropy Alloys ◽  
Oxide Scales ◽  
Temperature Oxidation ◽  
Internal Corrosion ◽  
High Entropy ◽  
Continuous Mass ◽  
Oxide Substrate ◽  
Kinetics Of

AbstractIn this study, the effect of Al on the high temperature oxidation of Al-containing refractory high entropy alloys (RHEAs) Ta-Mo-Cr-Ti-xAl (x = 5; 10; 15; 20 at%) was examined. Oxidation experiments were performed in air for 24 h at 1200 °C. The oxidation kinetics of the alloy with 5 at% Al is notably affected by the formation of gaseous MoO3 and CrO3, while continuous mass gain was detected for alloys with the higher Al concentrations. The alloys with 15 and 20 at% Al form relatively thin oxide scales and a zone of internal corrosion due to the formation of dense CrTaO4 scales at the interface oxide/substrate. The alloys with 5 and 10 at% Al exhibit, on the contrary, thick and porous oxide scales because of fast growing Ta2O5. The positive influence of Al on the formation of Cr2O3 followed by the growth of CrTaO4 to yield a compact scale is explained by getter and nucleation effects.

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