Water Absorption Characteristics of Obatanpa and Mamaba Maize Hybrids (Zea mays)

2006 ◽  
Vol 2 (3) ◽  
Author(s):  
Ahmad Addo ◽  
Ato Bart-Plange ◽  
Komla Dzisi
Keyword(s):  
Zea Mays ◽  
Diffusion Coefficient ◽  
Water Absorption ◽  
Diffusion Coefficients ◽  
Type Equation ◽  
Water Diffusion ◽  
Energy Of Activation ◽  
Absorption Kinetics ◽  
Maize Hybrids ◽  
Absorption Characteristics

Water absorption characteristics of two newly-released maize hybrids, Obatanpa and Mamaba, during soaking were measured at four temperatures of 30, 40, 50 and 60ºC. The absorption kinetics followed the Fick's law of diffusion during the first hours of soaking. The values determined for water diffusion coefficients varied from 7.31 x 10-12 to 9.33 x 10-12 m2/s and from 6.30 x 10-12 to 8.25 x 10-12 m2/s for Obatanpa and Mamaba respectively. An Arrhenius–type equation was used to relate the diffusion coefficient of Obatanpa and Mamaba to temperature, and the energy of activation for Obatanpa and Mamaba was estimated. The values determined were 6.54 kJ/mol and 6.82 kJ/mol for Obatanpa and Mamaba respectively.

scholarly journals Modelling of the Water Absorption Kinetics and Determination of the Water Diffusion Coefficient in the Pith ofRaffia viniferaof Bandjoun, Cameroon

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
E. Tiaya Mbou ◽  
E. Njeugna ◽  
A. Kemajou ◽  
N. R. Tagne Sikame ◽  
D. Ndapeu
Keyword(s):  
Water Absorption ◽  
Diffusion Coefficients ◽  
Gravimetric Method ◽  
Water Diffusion ◽  
Radial Position ◽  
Absorption Kinetics ◽  
Absorption Phenomenon ◽  
Longitudinal Position ◽  
Percentage Of Water Absorption ◽  
Two Stages

The present work focuses on the study of the water absorption phenomenon through the pith ofRaffia viniferaalong the stem. The water absorption kinetics was studied experimentally by the gravimetric method with the discontinuous control of the sampling mass at temperature of 30°C. The samples of 70 mm × 8 mm × 4 mm were taken from twelve sampling zones of the stem ofRaffia vinifera. The result shows that the percentage of water absorption of the pith ofRaffia viniferaincreases from the periphery to the center in the radial position and from the base to the leaves in the longitudinal position. Fick’s second law was adopted for the study of the water diffusion. Eleven models were tested for the modelling of the water absorption kinetics and the model of Sikame Tagne (2014) is the optimal model. The diffusion coefficients of two stages were determined by the solution of the Fick equation in the twelve sampling zones described by Sikame Tagne et al. (2014). The diffusion coefficients decreased from the center to the periphery in the radial position and from the base to the leaves in the longitudinal position.

Comment on negative diffusion coefficients in quasi-linear theory

1971 ◽  
Vol 5 (1) ◽  
pp. 131-133 ◽  
Author(s):  
David Montgomery ◽  
Stephen Bodner
Keyword(s):  
Diffusion Coefficient ◽  
Linear Theory ◽  
Diffusion Coefficients ◽  
Electron Distribution ◽  
Type Equation ◽  
Diffusion Type ◽  
Negative Diffusion

A recent paper on quasiinear theory by Klozenberg & Bernstein is commented upon. It is argued that improper treatment of the perturbed electron distribution for damped waves has led to a diffusion-type equation with a negative diffusion coefficient.

Influence of fungal infection on the long-term water absorption and morphological behavior of bagasse fiber/polypropylene composites at different exposure times

2013 ◽  
Vol 20 (4) ◽  
pp. 351-357 ◽  
Author(s):  
Behzad Kord ◽  
Seyyed Khalil Hosseinihashemi ◽  
Mehdi Modirzare
Keyword(s):  
Water Absorption ◽  
Diffusion Coefficients ◽  
Water Diffusion ◽  
White Rot ◽  
Fungal Decay ◽  
Melt Mixing ◽  
Polypropylene Composites ◽  
Bagasse Fiber ◽  
Control Samples

AbstractIn this study, the effect of fungal decay on the long-term water absorption of bagasse fiber/polypropylene composites at different exposure times was studied. For this purpose, the blend composites were prepared through the melt mixing of bagasse fiber with polypropylene at 40:60% weight ratios, with 2% coupling agent for all formulations. Then, the samples were exposed to brown-rot (Coniophora puteana) and white-rot (Trametes versicolor) fungal treatments for 8, 12 and 16 weeks with the Kolle flask method. The long-term water absorptions of samples were evaluated by immersing them in water at room temperature for several weeks, and water diffusion coefficients were also calculated by evaluating the water absorption isotherms. Also, the morphology of composites was characterized using scanning electron microscopy (SEM). The results showed that the water absorption of samples was actually much higher after both types of rotting and was significantly higher than that of control samples. Also, the water absorption of white-rotted samples was higher than that of brown-rotted and control samples for all weeks of fungal exposure times. In addition, the control sample and composite after 16 weeks of exposure to white-rot fungi exhibited the lowest and highest water diffusion coefficients, respectively. The mechanism of water absorption of samples against fungal decay at different exposure times followed the kinetics of a Fickian diffusion process. Furthermore, the SEM micrographs showed that the extent of degradation increased with increasing exposure time to fungus.

scholarly journals Physical properties and water absorption kinetics of three varieties of Mucuna beans

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ajibola B. Oyedeji ◽  
Olajide P. Sobukola ◽  
Ezekiel Green ◽  
Oluwafemi A. Adebo
Keyword(s):  
Physical Properties ◽  
Water Absorption ◽  
Rate Constant ◽  
Geometric Mean ◽  
Seed Mass ◽  
Activation Energies ◽  
Mucuna Pruriens ◽  
Absorption Kinetics ◽  
Kinetics Of ◽  
Soaking Temperature

AbstractThe physical properties and water absorption kinetics of three varieties of Mucuna beans (Mucuna pruriens, Mucuna rajada and Mucuna veracruz) were determined in this study. Physical properties including length, width, thickness, geometric mean diameter, sphericity, porosity, bulk density, area, volume and one thousand seed mass were calculated while hydration kinetics was studied by soaking Mucuna beans in water at 30 °C, 40 °C and 50 °C and measuring water uptake at 9 h interval. Peleg’s equation was used to model the hydration characteristics and Arrhenius equation was used to describe the effect of temperature on Peleg’s rate constant k1 and to obtain the activation energies for soaking. Significant variations were observed in almost all the physical properties of the different varieties, however, there were no significant differences (p < 0.05) in their thicknesses and bulk densities. The effectiveness of fit of Peleg’s model (R2) increased with increase in soaking temperature. Peleg’s rate constant k1 decreased with increase in soaking temperature while k2 increased with temperature increase. Activation energies of Mucuna pruriens, Mucuna rajada and Mucuna veracruz were 1613.24 kJ/mol, 747.95 kJ/mol and 2743.64 kJ/mol, respectively. This study provides useful information about the properties of three varieties of Mucuna beans that could be of importance to processors and engineers for process design and optimization.

scholarly journals Selection approaches to the variation of responses to soil compaction stress among maize hybrids ( Zea mays L.)

2021 ◽  
Author(s):  
Maciej T. Grzesiak ◽  
Anna Maksymowicz ◽  
Barbara Jurczyk ◽  
Tomasz Hura ◽  
Grzegorz Rut ◽  
...  
Keyword(s):  
Zea Mays ◽  
Soil Compaction ◽  
Zea Mays L ◽  
Maize Hybrids ◽  
Compaction Stress

scholarly journals Effect of Water Ingress on the Mechanical and Chemical Properties of Polybutylene Terephthalate Reinforced with Glass Fibers

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1261
Author(s):  
Catarina S. P. Borges ◽  
Alireza Akhavan-Safar ◽  
Eduardo A. S. Marques ◽  
Ricardo J. C. Carbas ◽  
Christoph Ueffing ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Water Absorption ◽  
Water Uptake ◽  
Significant Influence ◽  
Water Immersion ◽  
Water Diffusion ◽  
Polybutylene Terephthalate ◽  
Chemical Changes ◽  
Water Ingress ◽  
Effect Of Water

Short fiber reinforced polymers are widely used in the construction of electronic housings, where they are often exposed to harsh environmental conditions. The main purpose of this work is the in-depth study and characterization of the water uptake behavior of PBT-GF30 (polybutylene terephthalate with 30% of short glass fiber)as well as its consequent effect on the mechanical properties of the material. Further analysis was conducted to determine at which temperature range PBT-GF30 starts experiencing chemical changes. The influence of testing procedures and conditions on the evaluation of these effects was analyzed, also drawing comparisons with previous studies. The water absorption behavior was studied through gravimetric tests at 35, 70, and 130 °C. Fiber-free PBT was also studied at 35 °C for comparison purposes. The effect of water and temperature on the mechanical properties was analyzed through bulk tensile tests. The material was tested for the three temperatures in the as-supplied state (without drying or aging). Afterwards, PBT-GF30 was tested at room temperature following water immersion at the three temperatures. Chemical changes in the material were also analyzed through Fourier-transform infrared spectroscopy (FTIR). It was concluded that the water diffusion behavior is Fickian and that PBT absorbs more water than PBT-GF30 but at a slightly higher rate. However, temperature was found to have a more significant influence on the rate of water diffusion of PBT-GF30 than fiber content did. Temperature has a significant influence on the mechanical properties of the material. Humidity contributes to a slight drop in stiffness and strength, not showing a clear dependence on water uptake. This decrease in mechanical properties occurs due to the relaxation of the polymeric chain promoted by water ingress. Between 80 and 85 °C, after water immersion, the FTIR profile of the material changes, which suggests chemical changes in the PBT. The water absorption was simulated through heat transfer analogy with good results. From the developed numerical simulation, the minimum plate size to maintain the water ingress unidirectional was 30 mm, which was validated experimentally.

scholarly journals Effect of Modification on the Fluid Diffusion Coefficient in Silica Nanochannels

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4030
Author(s):  
Gengbiao Chen ◽  
Zhiwen Liu
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Coefficients ◽  
Surface Effect ◽  
Bulk Water ◽  
Self Diffusion ◽  
Average Diffusion Coefficient ◽  
Average Diffusion ◽  
Chain Lengths ◽  
Fluid Diffusion ◽  
Self Diffusion Coefficient

The diffusion behavior of fluid water in nanochannels with hydroxylation of silica gel and silanization of different modified chain lengths was simulated by the equilibrium molecular dynamics method. The diffusion coefficient of fluid water was calculated by the Einstein method and the Green–Kubo method, so as to analyze the change rule between the modification degree of nanochannels and the diffusion coefficient of fluid water. The results showed that the diffusion coefficient of fluid water increased with the length of the modified chain. The average diffusion coefficient of fluid water in the hydroxylated nanochannels was 8.01% of the bulk water diffusion coefficient, and the diffusion coefficients of fluid water in the –(CH2)3CH3, –(CH2)7CH3, and –(CH2)11CH3 nanochannels were 44.10%, 49.72%, and 53.80% of the diffusion coefficients of bulk water, respectively. In the above four wall characteristic models, the diffusion coefficients in the z direction were smaller than those in the other directions. However, with an increase in the silylation degree, the increased self-diffusion coefficient due to the surface effect could basically offset the decreased self-diffusion coefficient owing to the scale effect. In the four nanochannels, when the local diffusion coefficient of fluid water was in the range of 8 Å close to the wall, Dz was greater than Dxy, and beyond the range of 8 Å of the wall, the Dz was smaller than Dxy.

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