scholarly journals A new empirical model for estimating the hydraulic conductivity of low permeability media

2015 ◽  
Vol 368 ◽  
pp. 478-483 ◽  
Author(s):  
S. Qi ◽  
Z. Wen ◽  
C. Lu ◽  
L. Shu ◽  
J. Shao ◽  
...  
Keyword(s):  
Grain Size ◽  
Hydraulic Conductivity ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Empirical Model ◽  
Coefficient Of Determination ◽  
Low Permeability ◽  
Indirect Determination ◽  
Fine Grained ◽  
The Moment

Abstract. Hydraulic conductivity (K) is one of the significant soil characteristics in terms of flow movement and solute transport. It has been recognized that K is statistically related to the grain-size distribution. Numerous models have been developed to reveal the relationship between K and the grain-size distribution of soil, but most of these are inappropriate for fine-grained media. Therefore, a new empirical model for estimating K of low permeability media was proposed in this study. In total, the values of K of 30 soil samples collected in the Jiangning District of Nanjing were measured using the single-ring infiltrometer method. The new model was developed using the percentages of sand, silt and clay-sized particles, and the first and the second rank moment of the grain-size through the moment method as predictor variables. Multivariate nonlinear regression analysis yielded a coefficient of determination (R2) of 0.75, indicating that this empirical model seems to provide a new approach for the indirect determination of hydraulic conductivity of low permeability media.

scholarly journals Microstructural evolution in the fine-grained region of the Siple Dome (Antarctica) ice core

2011 ◽  
Vol 57 (206) ◽  
pp. 1046-1056 ◽  
Author(s):  
R.W. Obbard ◽  
K.E. Sieg ◽  
I. Baker ◽  
D. Meese ◽  
G.A. Catania
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Electron Backscatter Diffraction ◽  
Ice Core ◽  
Axis Orientation ◽  
Fine Grained ◽  
Depth Analysis ◽  
Siple Dome ◽  
Mean Grain Size

AbstractAn in-depth analysis of seven samples from the Siple Dome (Antarctica) ice core, using optical microscopy and electron backscatter diffraction, illustrates rotational recrystallization or polygonization in the fine-grained region of the core between 700 and 800 m. Between 640 and 700 m, the microstructure is characterized by a bimodal grain-size distribution and a broken girdle fabric with evidence of polygonization. From 727 to 770 m, mean grain size decreases and a single-maximum fabric is found, and, by 790 m, mean grain size has again increased and a multiple-maxima fabric manifests itself. We compare grain-size distribution, c- and a-axis orientation, and misorientation between adjacent grains. We found that misorientations between adjacent grains in the 727–770 m region were predominantly low-angle and typically around a common a-axis, suggesting polygonization. This conclusion is supported by radar evidence of a physical disturbance at 757 m, which may be correlated with higher than usual strain in the 700–800 m range. Below 770 m, larger less regular misorientations and textural evidence show that migration recrystallization is the primary recrystallization mechanism.

scholarly journals MINERAL COMPOSITION OF SOME LATGALE LAKE SEDIMENTS

2019 ◽  
Vol 1 ◽  
pp. 304
Author(s):  
Rasma Tretjakova ◽  
Andris Karpovičs
Keyword(s):  
Grain Size ◽  
Lake Sediments ◽  
Size Distribution ◽  
Clay Minerals ◽  
Mineral Composition ◽  
Grain Size Distribution ◽  
Sandy Loam ◽  
Clay Fraction ◽  
Fine Grained ◽  
Two Samples

Our research is focused on sedimentological conditions and postdepositional changes of recent fine grained lake sediments. We used bulk sediment mineralogical composition and grain size distribution as indicators to identify sediment source areas and possible changes during Holocene. We analysed fine grained (clayey) sediments from three Latgale lakes - Zeili, Pauguļi and Plusons, situated in Latgale upland. Lake sediments cover Late Pleistocene glacial deposits – loam and sandy loam. Bulk mineral composition of 6 sediment samples was determined by X-ray diffraction (XRD). Sediments contained typical minerals found in surrounding glacial sediments: rock-forming minerals as quartz, plagioclase, albite, enstatite, dolomite, calcite, and clay minerals - illite, kaolinite. To identify postdepositional changes in lake sediments of Holocene age clay minerals in clay fraction (<2 mkm) should be analysed. Particularly illite, smectite mixed layered minerals - illite/smectite (I/Sm) and chlorite. Additionally, grain size distribution of studied lake sediments was analysed. Accordingly, our studied sediments are clays, silty clays and clayey silts with bimodal particle distribution, except two samples from Zeiļi and Plusons with unimodal distribution.

scholarly journals Assessment and Analysis of Precambrian Basement Soil Deposits Using Grain Size Distribution

2020 ◽  
Vol 66 (4) ◽  
pp. 235-243
Author(s):  
Gideon Layade ◽  
Charles Ogunkoya ◽  
Victor Makinde ◽  
Kehinde Ajayi
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Textural Properties ◽  
Soil Samples ◽  
Sieve Analysis ◽  
Precambrian Basement ◽  
Statistical Parameters ◽  
Fine Grained ◽  
Transportation History

AbstractThe article presents the grain size distribution of soil samples from the Precambrian basement within the purview of the textural properties, deduced transportation history and the numerical assessments using statistical parameters. The fourteen soil samples collected from the study area were subjected to sieve analysis in the laboratory for the determination of their grain size distribution. The statistical parameters’ study includes the graphic mean, skewness, sorting and kurtosis. The result of the analysis of the soil samples ranged from coarse to fine-grained samples, moderately and poorly sorted, positively and negatively skewed and the kurtosis also shows leptokurtic as the most dominant which suggests the samples poorly distributed and moderately sorted at the centre of the grain size distribution. These results also suggest the geological environment of the soil samples could be responsible for the poorly and moderately sorted exhibited by the samples deposited in the location.

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