scholarly journals A method for describing equilibrium moisture content of forest fuels

1984 ◽  
Vol 14 (4) ◽  
pp. 597-600 ◽  
Author(s):  
Ralph M. Nelson Jr.
Keyword(s):  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Goodness Of Fit ◽  
Model Description ◽  
Data Sets ◽  
Temperature Hysteresis ◽  
Exponential Relationship ◽  
Isothermal Adsorption ◽  
Sorption Data ◽  
Forest Fuels

The isothermal adsorption and desorption of water vapor by forest fuels is represented with a two-parameter model based on an exponential relationship between Gibbs free energy change and equilibrium moisture content. The model is applied to five sets of sorption data in the literature to illustrate goodness of fit. Two of the data sets are well reproduced by the model; description of the remaining data is less satisfactory. Whether the deviations are due to experimental factors or a deficiency in the model is not determined. At constant temperature, hysteresis ratios tend to increase as percent relative humidity increases.

Moisture Sorption Characteristics of Dakuwa (Nigerian Cereal/Groundnut Snack)

2013 ◽  
Vol 9 (4) ◽  
pp. 499-504 ◽  
Author(s):  
Ocheme Boniface Ocheme ◽  
Chukwuma Charles Ariahu ◽  
Emmanuel Kongo Ingbian
Keyword(s):  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Goodness Of Fit ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Sorption Data ◽  
Moisture Contents ◽  
Monolayer Moisture ◽  
Increasing Temperature ◽  
Sorption Characteristics

AbstractThe moisture sorption characteristics of dakuwa at 10, 20, 30 and 400°C were studied. The experimental sorption data obtained were applied to BET, GAB, Oswin and Henderson equations to test fitness of the equations to moisture sorption of dakuwa. The sorption isotherms of dakuwa were type III isotherms (J shaped), and the equilibrium moisture content increased with increasing water activity but decreased with increasing temperature. The BET and GAB monolayer moisture contents all decreased with increasing temperature. For adsorption, the BET monolayer was higher (3.163–4.158 g/100 g solid) than that of GAB (2.931–3.728 g/100 g solid), but for desorption, the GAB monolayer (4.792–7.741 g/100 g solid) was higher than that of BET (3.962–4.480 g/100 g solid). Evaluation of goodness of fit of models revealed that moisture sorption of dakuwa was best modelled by GAB equation.

scholarly journals MODELING DYNAMIC ADSORPTION ISOTHERMS AND THERMODYNAMIC PROPERTIES OF SPECIALTY GROUND ROASTED-COFFEE (Coffee Arabica L.)

2019 ◽  
Vol 14 (1) ◽  
pp. 93 ◽  
Author(s):  
Gentil Andres Collazos-Escobar ◽  
Nelson Gutiérrez-Guzman ◽  
Henry A. Vaquiro Herrera
Keyword(s):  
Thermodynamic Properties ◽  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Adsorption Isotherms ◽  
Sorption Isotherms ◽  
Isosteric Heat ◽  
Roasted Coffee ◽  
Sorption Data ◽  
Specialty Coffee ◽  
Sensorial Attributes

Specialty coffee is highly differentiated product because of  its sensorial attributes: aroma, body and brand reputation. In specialized markets, these products are highly valued, and sometimes up to six times their commercial value is paid. Thus, it is essential to preserve their freshness. Sorption isotherms are necessary for determining and studying water sorption changes in specialty coffee during storage. This study aimed to determine the adsorption isotherms of specialty ground roasted-coffee at temperatures of 25 °C, 30 °C and 40 °C and water activities between 0.1 and 0.8 using the dynamic dewpoint method (DDI). The experiment sorption data were modeled using 12 different equations with non-linear regression to represent the dependence of the equilibrium moisture content with both water activity and temperature. In addition, the thermodynamic properties were determined with the experiment adsorption data. The results showed that type III isotherms were obtained according to the Brunauer classification, and the Weibull equation satisfactorily modeled the effect of the temperature on the hygroscopic equilibrium in the specialty ground roasted-coffee. The results of thermodynamic analysis showed that the net isosteric heat of adsorption and Gibbs free energy decreased as the equilibrium moisture content increased, indicating the amount of energy released, a strong bond energy between water molecules in the product components and spontaneity in the adsorption process. The entropy of the adsorption increased with the moisture content, leading to product stability conditions during storage. The results were similar to those reported for the roasted and ground coffee of others cultivars.

Equilibrium moisture content and timelag of dead Pinus pinaster needles

2014 ◽  
Vol 23 (5) ◽  
pp. 721 ◽  
Author(s):  
Sérgio Lopes ◽  
Domingos Xavier Viegas ◽  
Luís Teixeira de Lemos ◽  
Maria Teresa Viegas
Keyword(s):  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Pinus Pinaster ◽  
Predictive Ability ◽  
Food Products ◽  
Forest Fuels ◽  
Best Fitting ◽  
Fine Fuels ◽  
Almost All ◽  
Moisture Content Determination

Modelling adsorption and desorption processes and equilibrium moisture content of dead fine fuels below fibre saturation is required to provide an accurate prediction of their drying and wetting processes within the range where flammability increases rapidly with decreasing moisture content. Data from laboratory tests on sorption processes and equilibrium moisture content isotherms of dead Pinus pinaster (Ait.) needles were used to evaluate several models applicable to fine forest fuels and agricultural and food products. Laboratory and field data were used to assess model accuracy in predicting drying and wetting curves and equilibrium moisture content isotherms showing a medium to high predictive ability for almost all cases. The best fitting combinations were obtained with the application of agricultural and food products models for drying and wetting phases and fine forest fuel models for equilibrium moisture content determination.

scholarly journals Sorption equilibrium and kinetics of thin-layer drying of green bell peppers

2018 ◽  
pp. 137
Author(s):  
Olga R.R. Gandolfi, Ramos Ferreira Goncalves ◽  
Renata C. F. Bonomo, Rafael daCosta I. Fontan
Keyword(s):  
Moisture Content ◽  
Thin Layer ◽  
Equilibrium Moisture Content ◽  
Air Velocity ◽  
Drying Time ◽  
Sorption Data ◽  
Page Model ◽  
Thin Layer Drying ◽  
Bell Peppers ◽  
Kinetics Of

Drying is a unit operation widely used in food preservation. It is important to know how this process takes place and the effects of variables such as temperature, relative humidity and air velocity. It is also essential to know the equilibrium moisture content of the product at the temperature under study. Thus, the objective of this study was to determine the sorption isotherms and evaluate the effects of temperature (60°C and 75°C) and air velocity (1.5 m s-1 and 3.0 m s-1) on the thin-layer drying curves of green bell peppers. The experimental sorption data were adjusted to the BET and GAB models, where the latter best described the sorption behavior of the pepper. It was also verified that with the elevation in temperature lower values for the equilibrium moisture content were obtained. The drying data were adjusted to the Page model, Henderson and Pabis model, Newton model and Fick model. From the latter model the effective diffusion coefficient of water in the project was determined, confirming that the increase in temperature did not increase with greater air velocity. The Page model was that which best fit to all drying conditions. The variation in drying air velocity little affected the kinetics of the process, observing only a small reduction in drying time with increased air velocity (approximately 2.4%), while temperature showed the greatest influence, with a large reduction in drying time with increase in this variable (around 41.4%).

scholarly journals Modeling sorption isotherms and isosteric heat of sorption of roasted coffee beans

2018 ◽  
Author(s):  
Gentil Andres Collazos-Escobar ◽  
Nelson Gutiérrez-Guzmán ◽  
Henry Alexander Vaquiro-Herrera ◽  
Erika Tatiana Cortes-Macias
Keyword(s):  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Sorption Isotherms ◽  
Isosteric Heat ◽  
Dew Point ◽  
Roasted Coffee ◽  
Sorption Data ◽  
Heat Of Sorption ◽  
Coffee Beans ◽  
Roasted Coffee Beans

The aim of this work was determine the sorption isotherms in roasted beans of specialty coffee at temperatures of 25, 30 and 40 °C and water activities between 0.1 and 0.8 using the dynamic dew point method. The experimental sorption data were modeled using 12 different equations to represent the dependence of equilibrium moisture content with aw and temperature. The net isosteric heat of sorption was determined from the experimental sorption data using the Clausius-Clapeyron equation. The Weibull model satisfactorily modeled the effect of the temperature on the hygroscopic equilibrium in roasted coffee beans (R2adj =0.902 and RMSE = 0.00550 kg·kg-1d.b.). The net isosteric heat of sorption increase with increased moisture content. Keywords: water activity; sorption properties; equilibrium moisture content; hygroscopicity

Equilibrium Moisture Content of Semi-Defatted Pumpkin Seed Flour

2005 ◽  
Vol 1 (3) ◽  
Author(s):  
Nikolay D Menkov ◽  
Albena G Durakova
Keyword(s):  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Storage Temperature ◽  
Gravimetric Method ◽  
Pumpkin Seed ◽  
Sorption Data ◽  
Seed Flour ◽  
Equilibrium Data ◽  
Gab Model ◽  
Monolayer Moisture

Moisture equilibrium data (adsorption and desorption) of semi-defatted (fat 10.6 % wet basis) pumpkin seed flour were determined using the static gravimetric method of saturated salt solutions at three temperatures 10 °C, 25 °C, and 40 °C. The range of water activities for each temperature was between 0.11 and 0.85. Equilibrium moisture content decreased with the increase in storage temperature at any given water activity. The experimental data were fitted to five mathematical models (modified Oswin, modified Halsey, modified Chung-Pfost, modified Henderson and Guggenheim-Anderson-de Boer). The GAB model was found to be the most suitable for describing the sorption data. The monolayer moisture content was estimated using the Brunauer-Emmett-Teller equation.

Analysis of the moisture content of maize kernels in over-ripe plants

2006 ◽  
Vol 54 (4) ◽  
pp. 425-430
Author(s):  
T. Árendás ◽  
L. C. Marton ◽  
P. Bónis ◽  
Z. Berzsenyi
Keyword(s):  
Linear Regression ◽  
Moisture Content ◽  
Grain Yield ◽  
Equilibrium Moisture Content ◽  
Weather Conditions ◽  
Positive Correlation ◽  
Maize Grain Yield ◽  
Maize Grain ◽  
Maize Kernels

The effect of varying weather conditions on the moisture content of the maize grain yield was investigated in Martonvásár, Hungary from late August to late September, and from the 3rd third of September to the 1st third of Novemberbetween 1999 and 2002. In every year a close positive correlation (P=0.1%) could be observed between the moisture content in late September and the rate of drying down in October. Linear regression was used each year to determine the equilibrium moisture content, to which the moisture content of kernels returned if they contained less than this quantity of water in late September and harvesting was delayed. In the experimental years this value ranged from 15.24-19.01%.

scholarly journals Goodness-of-Fit Tests for Bivariate Time Series of Counts

Econometrics ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 10
Author(s):  
Šárka Hudecová ◽  
Marie Hušková ◽  
Simos G. Meintanis
Keyword(s):  
Goodness Of Fit ◽  
Probability Generating Function ◽  
Parametric Bootstrap ◽  
Real Data ◽  
Data Sets ◽  
Test Statistics ◽  
Finite Sample ◽  
Generalized Poisson ◽  
Goodness Of Fit Tests ◽  
Monte Carlo Experiments

This article considers goodness-of-fit tests for bivariate INAR and bivariate Poisson autoregression models. The test statistics are based on an L2-type distance between two estimators of the probability generating function of the observations: one being entirely nonparametric and the second one being semiparametric computed under the corresponding null hypothesis. The asymptotic distribution of the proposed tests statistics both under the null hypotheses as well as under alternatives is derived and consistency is proved. The case of testing bivariate generalized Poisson autoregression and extension of the methods to dimension higher than two are also discussed. The finite-sample performance of a parametric bootstrap version of the tests is illustrated via a series of Monte Carlo experiments. The article concludes with applications on real data sets and discussion.

scholarly journals HANDY: a device for assessing resistance to mechanical crushing of maize kernel

Plant Methods ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Yuan Su ◽  
Yang Xu ◽  
Tao Cui ◽  
Xiaojun Gao ◽  
Guoyi Xia ◽  
...  
Keyword(s):  
Moisture Content ◽  
Goodness Of Fit ◽  
Function Analysis ◽  
Physical Damage ◽  
Maize Kernel ◽  
Rotating Speed ◽  
Maize Cultivars ◽  
Maize Varieties ◽  
New Perspective ◽  
Mechanical Crushing

Abstract Background How to control the physical damage during maize kernel harvesting is a major problem for both mechanical designers and plant breeders. A limitation of addressing this problem is lacking a reliable method for assessing the relation between kernel damage susceptibility and threshing quality. The design, construction, and testing of a portable tool called “HANDY”, which can assess the resistance to mechanical crushing in maize kernel. HANDY can impact the kernel with a special accelerator at a given rotating speed and then cause measurable damage to the kernel. These factors are varied to determine the ideal parameters for operating the HANDY. Results Breakage index (BI, target index of HANDY), decreased as the moisture content of kernel increased or the rotating speed decreased within the tested range. Furthermore, the HANDY exhibited a greater sensitivity in testing kernels at higher moisture level influence on the susceptibility of damage kernel than that in Breakage Susceptibility tests, particularly when the centrifugation speed is about 1800 r/min and the centrifugal disc type is curved. Considering that the mechanical properties of kernels vary greatly as the moisture content changes, a subsection linear (average goodness of fit is 0.9) to predict the threshing quality is built by piecewise function analysis, which is divided by kernel moisture. Specifically, threshing quality is regarded as a function of the measured result of the HANDY. Five maize cultivars are identified with higher damage resistance among 21 tested candidate varieties. Conclusions The HANDY provides a quantitative assessment of the mechanical crushing resistance of maize kernel. The BI is demonstrated to be a more robust index than breakage susceptibility (BS) when evaluating threshing quality in harvesting in terms of both reliability and accuracy. This study also offers a new perspective for evaluating the mechanical crushing resistance of grains and provides technical support for breeding and screening maize varieties that are suitable for mechanical harvesting.

Sign in / Sign up

Export Citation Format

Share Document