scholarly journals Modelling of Hydration Characteristics of Five Varieties of Cowpea Grains

2019 ◽  
pp. 1-16 ◽  
Author(s):  
J. Isa ◽  
A. S. Oyerinde ◽  
K. A. Jimoh ◽  
A. O. Jegede

Introduction: The hydration of grains is a process that consists of soaking them in water in order to increase their moisture content and this is a crucial step in industrialized processing and provides several beneficial effects on their physicochemical and nutritional qualities. Aims: This study focused on modeling of hydration characteristics of five varieties of cowpea which are: Gombe, Oloyin white, Drum, Oloyin brown and Sokoto cultivated in Nigeria. Methodology: The experiments were carried out using electronic water bath at five temperatures (30, 40, 50, 60, and 70°C) in three replications. The amount of water absorption by five selected varieties of cowpea grains was calculated by measuring the increase in the mass of soaked grains per time. Five standard models of water absorption were fitted to the experimental data. Coefficient of determination (R2), chi-square (x2) and root mean square error (RMSE) were used to evaluate the models. Results: The initial moisture content of the saturated cowpea was estimated as 13.56 ±1.15, 15.05 ±2.27, 13.30 ±0.37, 10.85 ±0.13, 12.40 ±0.13 for Gombe, Oloyin white, Drum, Oloyin brown and Sokoto varieties respectively. The water uptake of the cowpea was faster at the initial stage and gradually slow down until the equilibrium moisture content was attained for all the varieties. Conclusions: Weibull model was adjudged as the best fitted model for describing the water absorption property of all the varieties of the cowpea and the Activation energy of Gombe, Oloyin white, Drum, Oloyin brown and Sokoto varieties are 42.26 ± 4.65, 40.36 ±8.90, 39.47 ±8.62, 43.08 ±5.25 and 39.66 ±6.72 respectively.

2020 ◽  
Vol 187 ◽  
pp. 04007
Author(s):  
Chatsuda Sittipa ◽  
Siva Achariyaviriya ◽  
Aree Achariyaviriya ◽  
James C. Moran

An important step in the development of passion fruit tea products is the drying procedure. This procedure uses a lot of energy. The optimization of drying needs knowledge of the drying kinetics. This paper focuses the development of drying kinetics for passion fruit peel. The experiments were conducted utilizing a thin layer dryer with drying air temperatures in the range of 45°C to 65°C The drying air velocity was constant at 1 m/s. The passion fruit peel were dried from their initial moisture content of 559±16% db to a final moisture content of 50±1% db. The models for the kinetic drying proposed by the authors are the Newton model, Page model and the Logarithmic model. The parameters for the drying kinetic models were found by curve fitting the experimental data using non-linear regression. The criteria for evaluating the models were the coefficient of determination (R2), a root mean square error (RMSE) and a reduced chi- square (x2). It was found that the drying kinetic model for passion fruit peel which gave the best fit was the Page model. This drying kinetic model can be applied to find optimum drying conditions.


Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4565 ◽  
Author(s):  
Lucyna Domagała

The aim of this study was to present the problem of durability of structural lightweight concrete made of a sintered fly ash aggregate. The issue of durability was researched for 12 concrete series in terms of their water absorption, water permeability, and freeze-thaw resistance. Additionally, the microstructure of several concretes was analyzed with a scanning electron microscope (SEM). In the durability research, the influences of the following parameters were taken into consideration: The initial moisture content of sintered fly ash (mc = 0, 17–18, and 24–25%); the aggregate grading (4/8 and 6/12 mm); and the water-cement ratio (w/c = 0.55 and 0.37). As a result of various compositions, the concretes revealed different properties. The density ranged from 1470 to 1920 kg/m3, and the corresponding strength ranged from 25.0 to 83.5 MPa. The durability research results of tested lightweight concretes showed that, despite considerably higher water absorption, a comparable water permeability and comparable or better freeze-thaw resistance in relation to normal-weight concrete may be present. Nevertheless, the fundamental requirement of lightweight concrete to achieve good durability requires the aggregate’s initial moisture content to be limited and a sufficiently tight cement matrix to be selected. The volume share of the cement matrix and aggregate, the cement content, and even the concrete strength are of secondary importance.


Author(s):  
O.U. Dairo ◽  
T.M.A. Olayanju

Fundamental Information on Drying and Re-Wetting Characteristics of Agricultural Seeds Is Required in the Design and Aeration Systems as Well as in the Prediction of Drying Rate Using Various Mathematical Models. Thin-Layer Drying Experiments Were Conducted Using Air-Ventilated Oven to Simulate the Artificial Drying at Various Moisture Contents of Sesame Seed (6.9 to 18.2 % W.b) at Three Drying Temperatures of 40, 50 and 60OC. Five Drying Models Were Evaluated for the Thin-Layer Data. the Page Equation Fitted the Data Best, where Selection of the Best Model Was Obtained by Comparing the Coefficient of Determination (R2), the Standard Error of Moisture Content (SEM) and Mean Relative Percent Error (e) between the Experimental and Estimated Values. the Drying Rate of Sesame Seed under Drying Conditions Increased with Increased Temperature of Drying( 40 to 60OC) and Initial Moisture Content of Seed( 6.9, 11.5 and 18.2 % W.b). the Parameters “K” of the Page Model Increased with Increase in Temperature, while, Parameter ”n” Decreased with Temperature Increase and Increased with Increase in Moisture Content of Seed. the Effective Diffusivity Was Found to Be 2.32 X 10-11 M2s-1.


Author(s):  
H. Boris ◽  
D. Shrilekha ◽  
J. Sujata

Drying is a complex phenomenon and study of drying kinetics and modelling is very important for describing the moisture movement with respect to time and predicting the dryer performance. Considering this fact, vacuum drying characteristics of cherry pepper was studied at different drying temperatures (50, 60 and 70oC). Cherry pepper were dried from initial moisture content of about 400% (dry basis) to 13 – 14.5% (dry basis) at different temperatures at 630 mm Hg vacuum. Time required to dry cherry peppers at 50, 60 and 70p C plate temperatures were 19 h, 9.75 h and 8 h respectively. Moisture reduction of cherry pepper at various temperatures was modelled using thin-layer models viz. Lewis, Page, Modified Page and Henderson and Pabis model. Based on highest value of coefficient of determination, lowest values of reduced chi square and root mean square error, Modified Page model was found to be the best fit. Moisture diffusivity increased from 6.27 × 10-10 to 1.9× 10-9m2s-1 as plate temperature increased from 50 – 70oC. Activation energy was estimated to be 50.98 kJkgmol-1.


Author(s):  
Daniel E. C. de Oliveira ◽  
Osvaldo Resende ◽  
Lílian M. Costa ◽  
Glicélia P. Silva ◽  
Juliana de F. Sales

ABSTRACT ‘Sucupira-branca’ (Pterodon emarginatus Vogel) is a tree from ‘Cerrado’ and stands out mainly for its pharmacological properties; however, there are no technological information about its post-harvest operations. Thus, the aim of this study was to determine the sorption isotherms of ‘sucupira-branca’ fruits for different air conditions and obtain the values of desorption isosteric heat, depending on the equilibrium moisture content of the product. The equilibrium moisture content of ‘sucupira-branca’ fruits was determined by dynamic method for temperatures of 25, 30, 35 and 40 °C and water activities for each temperature between 0.270 and 0.775. The models Chung-Pfost, Copace, Modified Halsey, Oswin Modified and Sigma Copace obtained high coefficient of determination (R2) and low chi-square (χ2), relative mean error (P) and estimated mean error (SE), and the Copace model was selected to represent the desorption isotherms. The isosteric heat increases with the reduction of equilibrium moisture content and required more energy to remove water from the ‘sucupira-branca’ fruit.


2018 ◽  
Vol 3 ◽  
pp. 11-16
Author(s):  
Belyj V.S. ◽  
Bryl S.V.

In this article the technique of a research of correlation dependence between initial and final moisture content of the foam-polymer-mineral (PPM) insulation of an underground heat steel pipe and also results of check of a statistical hypothesis of a type of distribution of a random variable of water absorption of PPM isolation is offered. The nature of distribution established as a result of a research speaks about existence of a limit of opportunities of PPM isolation of a pipe for water absorption – isolation with low initial moisture content is capable to absorb in itself more moisture and vice versa. Absorption of moisture happens until the value of final moisture content of PPM isolation does not reach extremely possible value approximately identical on all volume of isolation.


2020 ◽  
pp. 1623-1629
Author(s):  
Lílian Moreira Costa ◽  
Osvaldo Resende ◽  
Daniel Emanoel Cabral de Oliveira ◽  
José Mauro Guimarães Carvalho ◽  
Sarah Gabrielle Sousa Bueno ◽  
...  

This work aimed to study the drying kinetics of canola seeds, fit mathematical models and obtain the effective diffusion coefficient. Canola seeds with initial moisture content of 0.3653 (decimal, d.b.) were subjected to drying in a forced ventilation oven at temperatures of 40, 60, 80 and 100 °C and relative humidity of 37.15, 16.93, 8.35, 4.41 and 2.47%, respectively. The samples were dried on trays without perforations, containing approximately 77 g, in three replicates. A final moisture content of 0.080 ± 0.004 (decimal, d.b.) was established to determine the drying curves and fit the mathematical models. The mathematical models were selected considering the mean estimated error, chi-square, coefficient of determination, mean relative error, and Akaike (AIC) and Bayesian (BIC) information criteria. Drying time decreased with increasing temperature. Based on the best values of the statistical parameters and together with the Akaike and Bayesian information criteria, the Page model was selected to represent the drying kinetics of canola seeds. The effective diffusion coefficients showed magnitudes between 0.153x10-11 and 1.221x10-11 (m2 s-1), and their values increased with temperature increase, being described by the Arrhenius equation, with activation energy of 33.94 kJ mol-1, an important piece of information to consider when designing drying equipment


Author(s):  
L. Hübschen

AbstractThe present paper shows the detectable factors on which a sorption isotherm depends. Even if it is well-known that a sorption isotherm is most essentially conditioned by influences of the respective tobacco variety, other factors, such as temperature, initial moisture content, or fibre dimension, play a part as well. In general, a sorption isotherm constitutes a ''summation'' of such factors and, in the end, a combination of desorption and adsorption if the tobacco is dried or moistened from the average commercial moisture content. The tobacco hysteresis is experimentally investigated and discussed


Agrotek ◽  
2018 ◽  
Vol 2 (6) ◽  
Author(s):  
Wilson Palelingan Aman

<em>A research about cocoa beans drying used solar tunnel dryer with photovoltaic module driven have conducted in Manokwari. Solar tunnel dryer used in this research adapted from type Hohenheim with photovoltaic module and integrated air heat collector has been installed at the Department of Agricultural Technology, Papua State University Manokwari to dried cocoa beans. The objectives of this research were to design solar tunnel dryer and evaluate it�s performance in dryed cocoa beans. The result obtained was a new construction of solar tunnel dryer for cocoa beans with dimensions 6 m of length and 0,9 m of wide. The dryer completed with photovoltaic module to drive the blowers of hot drying air. �Performance test of the dryer showed that drying of 10 kg of cocoa beans with initial moisture content about 70% wet basis needed 13 hours of drying time to achieved final moisture content about 7,17% wet basis. The drying time achieved was faster compared than traditional solar drying that needed 20 hours of drying time. The maximum temperature achieved in drying chamber was 60 <sup>o</sup>C.</em>


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