The effect of initial moisture content and infiltration quantity on redistribution of soil water

Soil Research ◽  
1974 ◽  
Vol 12 (1) ◽  
pp. 15 ◽  
Author(s):  
T Talsma

The effects of initial moisture content and infiltration quantity on redistribution of water were studied in a loam, a fine sand, and a coarse sand. Moisture profiles during redistribution were obtained by gamma ray attenuation. Measured values of the hydraulic properties of these soils were used to calculate fluxes at the transition from drainage to wetting. The results were used to check a recent analysis of Peck. Gravity effects dominated in both sands, while in the loam capillary effects dominated at the smaller initial moisture contents and infiltration quantities. In all materials, increasing initial moisture content or infiltration quantity increased the contribution of gravity to the flux at the transition, and decreased the contribution due to capillary potential gradients. For a particular material, it depends on the magnitude of these fluxes whether mean moisture contents in the draining zone will be higher or lower at increasing values of initial moisture content or infiltration quantity.

1976 ◽  
Vol 39 (4) ◽  
pp. 244-245 ◽  
Author(s):  
G. BEETNER ◽  
T. TSAO ◽  
A. FREY ◽  
K. LORENZ

Triticale kernels were extruded using a Brabender Plasticorder extruder with ¾-inch rifled barrel and 1:1 flight depth ratio screw. Whole grain samples were extruded at initial moisture contents of 15, 20, and 25%. Debranned samples were extruded at an initial moisture content of 22%. Barrel temperatures of 350, 400, and 450 F and nozzle openings of 1/8 inch and 1/16 inch were used. The products were analyzed for thiamine and riboflavin content. Results were corrected for final moisture content and expressed as fraction retained. A multiple regression was done to determine the relationship between independent and derived variables, and the retention. Riboflavin retention was correlated simply as a function of barrel temperature. Thiamine retention of the debranned material was correlated as a function of nozzle size and barrel temperature. Thiamine retention of the whole grain samples was correlated for nozzle size, first and second order temperature effects, and confounding between nozzle size and temperature.


Toxins ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 535
Author(s):  
Yun-qi Wen ◽  
Li-li Xu ◽  
Chang-hu Xue ◽  
Xiao-ming Jiang

With high fat and protein content, maize germ is easily infected with fungus and mycotoxins during its storage. The qualities and safety of germ and its processing products may be affected by the storage. However, studies on the effect of storage on quality and polluted mycotoxin level of maize germ are limited. In this study, maize germ was stored with different initial moisture contents (5.03, 9.07, 11.82 and 17.97%) or at different relative humidity (75, 85 and 95%) for 30 days. The quality indices of germ (moisture content and crude fat content) and their produced germ oils (color, acid value and peroxide value) as well as the zearalenone (ZEN) and deoxynivalenol (DON) levels of germ, oils and meals were analyzed. Results showed that maize germ with high initial moisture contents (11.82, 17.97%) or kept at high humidity (95%) became badly moldy at the end of storage. Meanwhile, the qualities of these germ and oils showed great changes. However, the ZEN and DON contents of this maize germ, oils and meals stayed at similar levels (p < 0.05). Therefore, the storage could produce influence on the qualities of germ and oils, but showed limited effect on the DON and ZEN levels of germ and their processing products. According to this study, the storage condition of germ with no more than 9% moisture content and no higher than 75% humidity was recommended. This study would be benefit for the control of germ qualities and safety during its storage.


Soil Research ◽  
1973 ◽  
Vol 11 (2) ◽  
pp. 121 ◽  
Author(s):  
BJ Bridge ◽  
N Collis-George

The infiltration phenomena associated with a structurally unstable swelling soil are compared with those of a two-layer stable system of a fine sand layer over coarse sand, the fine sand simulating a slaked layer at the soil surface. Water content and bulk density are measured using dual source gamma ray attenuation, pore water pressures by means of individual tensiometer-transducer systems, and soil temperatures by means of individual thermistor-bridge systems. Analysis of the sand column using well-established principles shows that after the wetting front has passed the texture boundary, infiltration is controlled by Kmax of the fine sand layer and the negative moisture potential in the coarse sand at the texture boundary. After the wetting front penetrates the column, the moisture potential at the texture boundary becomes steady and is unaffected by the development of a capillary fringe and outflow at the base of the column. The negative moisture potentials at the texture boundary give rise to potential gradients up to 6.0 in the simulated slaked layer, and an infiltration rate several times that of Kmax. The low flow rates caused by the fine sand layer give rise to an unstable wetting front in the coarse sand and severe 'fingering' occurs. In the swelling soil column, with aggregates of the same size as the coarse sand, the infiltration throttle occurs immediately below the visibly slaked layer and not at the ground surface. Potential gradients through the throttle reach a maximum of 5.9 similar to that in the layered sand column, but the infiltration behaviour of swelling soil differs from the latter in other respects. Infiltration into the former does not occur under isothermal conditions, a 'hot front' 3�C above ambient occurring 2-3 mm ahead of the wetting front, and infiltration does not reach a constant rate because of changes in the hydraulic properties of the throttle with time. Moisture profiles in the swelling soil column during infiltration show the various zones described by Bodman and Colman (1944) for non-swelling soils. An enlarged apparent transition zone extend to 12 cm below the soil surface. Other properties such as density, moisture content, and total potential suggest that much of this apparent transition zone is really part of a transmission zone made up of layers of soil which have different properties because of swelling.


2018 ◽  
Vol 39 (6) ◽  
pp. 2821
Author(s):  
Wilker Alves Morais ◽  
Osvaldo Resende ◽  
Fernando Nobre Cunha ◽  
Vitor Marques Vidal ◽  
Nelmício Furtado da Silva ◽  
...  

Physical properties of soybean grains present differences as a function of cultivars and moisture content, with the correlation between physical properties. This study aimed to determine the characteristics related to the physical properties of grains with different moisture contents of three soybean cultivars. The experimental design was completely randomized design in a 3 × 6 factorial scheme with three replications, consisting of three soybean cultivars (6266 RSF IPRO, BMX Potência RR, and 14403Z6001) and six grain moisture contents (11, 13, 15, 17, 19, and 21% wb). Soybean grains presented an initial moisture content of 11.0, 11.0, and 10.8% wb, respectively for 6266 RSF IPRO, BMX Potência RR, and 14403Z6001. The other moisture contents were obtained by soaking in a BOD chamber maintained at 25 °C and 93% of relative humidity. We assessed volume, roundness, sphericity, surface area, volumetric shrinkage, and volumetric shrinkage rate. The data were submitted to the analysis of variance by the F-test (p < 0.05) and when significant, regression analysis was performed for grain moisture contents and the means of cultivars were compared by the Tukey’s test. Pearson’s correlation analysis was also carried out to represent the linearity between grain physical properties. The cultivar BMX Potência RR obtained the highest results for volume, roundness, sphericity, and surface area. Volume and surface area increased as the moisture content of soybean grains increased; the opposite was observed for roundness and sphericity. A linear increase in volumetric shrinkage was observed as moisture content increased. The values of the correlation coefficients of the linear regression models can be used to describe the relationships between physical properties.


2018 ◽  
Vol 61 (3) ◽  
pp. 1145-1155
Author(s):  
Drew F. Schiavone ◽  
Michael D. Montross

Abstract. This study characterized the hydraulic properties within baled switchgrass ( L., variety Alamo) and miscanthus (×), thereby enabling a better understanding of moisture changes in baled biomass during on-farm storage and/or high-solids bioconversion. Fully saturated bales were drained by gravity, and the moisture content was determined over 60 h. The average initial moisture content ranged between 55.9% and 71.9% (w.b.) for switchgrass and between 60.5% and 73.9% (w.b.) for miscanthus bales depending on the dry bale density. As the bale drained by gravity, rapid leaching of water was observed within the first 0.1 h, with a reduction in moisture content of 7.3 and 7.0 percentage points (w.b.) for switchgrass and miscanthus, respectively. Leaching then continued at a steady rate until termination of the experiment, with further reductions of 4.3 and 4.4 percentage points (w.b.) for switchgrass and miscanthus, respectively. Final moisture contents after 60 h ranged from 45.8% to 58.3% for switchgrass and from 48.7% to 60% for miscanthus, with the higher moisture contents observed in the lowest density bales. Hydraulic conductivity tests were carried out with bales of switchgrass and miscanthus with a constant head system. The average saturated hydraulic conductivity ranged between 0.103 and 0.616 cm s-1 for baled switchgrass and between 0.219 and 0.658 cm s-1 for baled miscanthus depending on the bale density. The matric suction of baled switchgrass was also assessed at variable densities and moisture contents using the contact filter paper method. The van Genuchten parameters were found to range between 0.235 and 0.270 m-1 for a and between 5.415 and 10.345 for n, depending on the density. Infiltration tests were also carried out on baled switchgrass at variable densities and moisture contents using a minidisk infiltrometer. The curve-fitting parameters of Philip’s two-term equation ranged between 0.086 × 10-6 and 0.779 × 10-6 cm s-1 for C1 and between 0.200 and 5.805 × 10-6 cm s-1/2 for C2, depending on the density and moisture content. The unsaturated hydraulic conductivity ranged between 0.019 and 0.272 cm s-1, while sorptivity ranged between 0.048 and 2.103 cm s-1/2, depending on the density and moisture content. These results provide data required to evaluate water flow through variable-density rectangular bales and indicate a potential to remove end-products of biomass conversion from baled biomass. Keywords: Biomass, Bioprocessing, Flushing, High solids.



2014 ◽  
Vol 11 (1) ◽  
pp. 153-158 ◽  
Author(s):  
M Akhtaruzzaman ◽  
MR Ali ◽  
MM Rahman ◽  
MS Ahamed

The fluidized bed drying principles for drying of tea in Bangladesh is thoroughly studied. The experiments were conducted to determine the drying curve, drying time, drying constant and dynamic equilibrium moisture contents of tea at the Bangladesh Tea Research Institute. Drying of tea in a fluidized bed dryer (Kilburn Vibro Fluid Bed Dryer) takes only 20 min for drying from an initial moisture content of 69.1% to a final moisture content of 2.8%. Temperatures of drying air were recorded to be 130°C at the inlet and 90°C at the outlet. The drying constant was found to be 31.05 h-1 and the dynamic equilibrium moisture contents were in the range of 18.3 to 2.0%. Finally the principle of fluidized bed drying was compared with the principle of conventional endless chain pressure type drying. DOI: http://dx.doi.org/10.3329/jbau.v11i1.18227 J. Bangladesh Agril. Univ. 11(1): 153-158, 2013


Author(s):  
Elton A. S. Martins ◽  
André L. D. Goneli ◽  
Alexandre A. Gonçalves ◽  
Cesar P. Hartmann Filho ◽  
Jerusa Rech ◽  
...  

ABSTRACT Agricultural products usually have their size reduced during the drying process. The quantification of the reduction in the dimensions is important for the development and optimization of equipment for the post-harvest of the product. The aim of the present study was to evaluate the effect of the variation in the moisture content during drying on the volumetric shrinkage of safflower grains and their respective axes. Safflower grains were harvested with an initial moisture content of approximately 0.445 decimal d.b. (dry basis) and subjected to drying in an oven with forced air circulation at 40 °C, until the grains reached a final moisture content of 0.073 ± 0.008 decimal d.b. During drying, the contraction of the axes, unit volumetric shrinkage and volumetric shrinkage of the mass of safflower grains were determined at different moisture contents. Based on these results, it can be concluded that reducing the moisture content causes a reduction in the axes of safflower grains and, consequently, reductions in the unit volumetric shrinkage and volumetric shrinkage of the mass of approximately 16 and 13%, respectively, and both variables can be represented by the linear shrinkage model.


2003 ◽  
pp. 117-121
Author(s):  
Irma Győriné Mile

We have carried out storage experiments with wheat varieties Magvas, Fatima, Mv Emma and Mv Pálma from the 2001 growth year. During the first half of the experiments quality parameters, such as changes in moisture, protein and gluten contents as well as pharinograph readings, falling numbers and sedimentation indices were analysed and tested at an average initial moisture content of 13%.The findings in the changes in the quality parameters of different wheat varieties with 13% moisture content as a function of storage time duration were published in an earlier paper of mine (12/04/2002).This paper wishes to give an account of the second part of the storage test when the moisture contents of the different varieties were raised to 16% and the changes in the quality parameters were monitored for seven weeks. The findings show that contrary to what had been experienced in the first half of the trial, there were no changes in the protein contents, pharinograph readings, water uptake or Zeleny counts and falling numbers showed decreases with each of the varieties tested.


2014 ◽  
Vol 34 (5) ◽  
pp. 972-979 ◽  
Author(s):  
Douglas N. Gonçalves ◽  
Osvaldo Resende ◽  
Lílian M. Costa ◽  
Mariana C. Prado

The Knowledge of the physical properties of agricultural products has great importance for the construction and operation of equipment for drying and storage, to achieve increased efficiency in post-harvest operations. The aim was to determine and analyze the physical properties of crambe fruits during drying at different temperatures. Crambe fruits with an initial moisture content of 0.36 (decimal d.b.) which was reduced by drying at 37.0; 58.8 and 83.5 ºC and relative humidity of 29.4; 11.2 and 3.2%, respectively, to 0.09 ± 1 (decimal d.b.). At different levels of moisture contents (0.36; 0.31; 0.26; 0.21; 0.17; 0.13 and 0.09 decimal d.b.), was evaluated the intergranular porosity, the bulk density, the true density as well as the volumetric shrinkage and the fruit mass. The study was installed by the factorial 3 x 7, and three drying temperatures and seven moisture contents in a randomized design. Data were analyzed using regression. The bulk density and the true density decreases along the drying process; the volumetric shrinkage and the mass increased with lower moisture content and the intergranular porosity decreased sharply with the increasing drying temperature.


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