Influence of compaction conditions on pore-size distribution and saturated hydraulic conductivity of a glacial till

2000 ◽  
Vol 37 (6) ◽  
pp. 1184-1194 ◽  
Author(s):  
Y Watabe ◽  
S Leroueil ◽  
J -P Le Bihan
Keyword(s):  
Hydraulic Conductivity ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Void Ratio ◽  
Glacial Till ◽  
Degree Of Saturation ◽  
Size Distributions ◽  
Pore Size Distributions ◽  
Compaction Degree

The paper examines the hydraulic conductivity of a nonplastic till from northern Quebec. It is shown that the hydraulic conductivity is strongly influenced by the compaction degree of saturation, and the variation of hydraulic conductivity with void ratio is influenced by compaction conditions. Determination of pore-size distributions and microphotographs provide evidence that changes in hydraulic conductivity are related to the fabric of the compacted specimens and macroporosity developing when the soil is compacted at degrees of saturation less than that at the optimum.Key words: till, hydraulic conductivity, microfabric.

A New X-Ray Scattering Method for Determining Pore-Size Distribution in Low-k Thin Films

2001 ◽  
Vol 714 ◽  
Author(s):  
Kazuhiko Omote ◽  
Shigeru Kawamura
Keyword(s):  
Thin Films ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Gas Adsorption ◽  
Size Distributions ◽  
X Ray ◽  
X Ray Scattering ◽  
Pore Size Distributions ◽  
Scattering Technique ◽  
Ray Scattering

ABSTRACTWe have successively developed a new x-ray scattering technique for a non-destructive determination of pore-size distributions in porous low-κ thin films formed on thick substrates. The pore size distribution in a film is derived from x-ray diffuse scattering data, which are measured using offset θ/2θ scans to avoid strong specular reflections from the film surface and its substrate. Γ-distribution mode for the pores in the film is used in the calculation. The average diameter and the dispersion parameter of the Γ-distribution function are varied and refined by computer so that the calculated scattering pattern best matches to the experimental pattern. The technique has been used to analyze porous methyl silsesquioxane (MSQ) films. The pore size distributions determined by the x-ray scattering technique agree with that of the commonly used gas adsorption technique. The x-ray technique has been also used successfully determine small pores less than one nanometer in diameter, which is well below the lowest limit of the gas adsorption technique.

scholarly journals Broadening the pore size of coal-based activated carbonviaa washing-free chem-physical activation method for high-capacity dye adsorption

RSC Advances ◽  
2018 ◽  
Vol 8 (26) ◽  
pp. 14488-14499 ◽  
Author(s):  
Longxin Li ◽  
Fei Sun ◽  
Jihui Gao ◽  
Lijie Wang ◽  
Xinxin Pi ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Pore Size Distribution ◽  
Pore Size ◽  
High Capacity ◽  
Dye Adsorption ◽  
High Rate ◽  
Physical Activation ◽  
Size Distributions ◽  
Pore Size Distributions ◽  
New Type

Aiming to overcome the limitations of the narrow pore size distributions of traditional activated carbon, we demonstrate a new type of activated carbon with a broadened pore size distribution for high-rate and high-capacity aqueous dye adsorption.

scholarly journals Determination of pore size distributions using the Dual Site-Bond Model: experimental evidence

2002 ◽  
Vol 206 (1-3) ◽  
pp. 393-400 ◽  
Author(s):  
R.H López ◽  
A.M Vidales ◽  
G Zgrablich ◽  
F Rojas ◽  
I Kornhauser ◽  
...  
Keyword(s):  
Experimental Evidence ◽  
Pore Size ◽  
Size Distributions ◽  
Bond Model ◽  
Pore Size Distributions ◽  
Dual Site

Two sides of the same inverse problem, in identifying the pore size distribution based on experiments with non-Newtonian fluids

2021 ◽  
Author(s):  
Martin Lanzendörfer
Keyword(s):  
Inverse Problem ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Forward Problem ◽  
Size Distributions ◽  
Pore Sizes ◽  
Pore Size Distributions ◽  
Flow Through ◽  
Effective Pore Size

<p>Following the capillary bundle concept, i.e. idealizing the flow in a saturated porous media in a given direction as the Hagen-Poiseuille flow through a number of tubular capillaries, one can very easily solve what we would call the <em>forward problem</em>: Given the number and geometry of the capillaries (in particular, given the pore size distribution), the rheology of the fluid and the hydraulic gradient, to determine the resulting flux. With a Newtonian fluid, the flux would follow the linear Darcy law and the porous media would then be represented by one constant only (the permeability), while materials with very different pore size distributions can have identical permeability. With a non-Newtonian fluid, however, the flux resulting from the forward problem (while still easy to solve) depends in a more complicated nonlinear way upon the pore sizes. This has allowed researchers to try to solve the much more complicated <em>inverse problem</em>: Given the fluxes corresponding to a set of non-Newtonian rheologies and/or hydraulic gradients, to identify the geometry of the capillaries (say, the effective pore size distribution).</p><p>The potential applications are many. However, the inverse problem is, as they usually are, much more complicated. We will try to comment on some of the challenges that hinder our way forward. Some sets of experimental data may not reveal any information about the pore sizes. Some data may lead to numerically ill-posed problems. Different effective pore size distributions correspond to the same data set. Some resulting pore sizes may be misleading. We do not know how the measurement error affects the inverse problem results. How to plan an optimal set of experiments? Not speaking about the important question, how are the observed effective pore sizes related to other notions of pore size distribution.</p><p>All of the above issues can be addressed (at least initially) with artificial data, obtained e.g. by solving the forward problem numerically or by computing the flow through other idealized pore geometries. Apart from illustrating the above issues, we focus on <em>two distinct aspects of the inverse problem</em>, that should be regarded separately. First: given the forward problem with <em>N</em> distinct pore sizes, how do different algorithms and/or different sets of experiments perform in identifying them? Second: given the forward problem with a smooth continuous pore size distribution (or, with the number of pore sizes greater than <em>N</em>), how should an optimal representation by <em>N</em> effective pore sizes be defined, regardless of the method necessary to find them?</p>

Determination of Pore Size Distributions in Nano-Porous Thin Films from Small Angle Scattering

2003 ◽  
Vol 766 ◽  
Author(s):  
Barry J. Bauer ◽  
Ronald C. Hedden ◽  
Hae-Jeong Lee ◽  
Christopher L. Soles ◽  
Da-Wei Liu
Keyword(s):  
Pore Size ◽  
Small Angle ◽  
Length Distribution ◽  
Dielectric Constants ◽  
Scattering Data ◽  
Size Distributions ◽  
Average Pore ◽  
Pore Size Distributions ◽  
Phase Size

AbstractSmall angle neutron and x-ray scattering (SANS, SAXS) are powerful tools in determination of the pore size and content of nano-porous materials with low dielectric constants (low-k) that are being developed as interlevel dielectrics. Several models have been previously applied to fit the scattering data in order to extract information on the average pore and/or matrix size. A new method has been developed to provide information on the size distributions of the pore and matrix phases based on the “chord length distribution” introduced by Tchoubar and Mering. Examples are given of scattering from samples that have size distributions that are narrower and broader than the random distribution typical of scattering described by Debye, Anderson, and Brumberger. An example of fitting SANS data to a phase size distribution is given.

Yield Stress Fluid Method to Measure the Pore Size Distribution of a Porous Medium

2010 ◽  
Author(s):  
Aimad Oukhlef ◽  
Abdlehak Ambari ◽  
Ste´phane Champmartin ◽  
Antoine Despeyroux
Keyword(s):  
Porous Media ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Size Distributions ◽  
First Approximation ◽  
Pore Size Distributions ◽  
Plastic Fluid ◽  
Present Technique ◽  
Mathematical Processing

In this paper a new method is presented in order to determine the pore size distribution in a porous media. This original technique uses the non Newtonian yield-pseudo-plastic rheological properties of some fluid flowing through the porous sample. In a first approximation, the very well-known and simple Carman-Kozeny model for porous media is considered. However, despite the use of such a huge simplification, the analysis of the geometry still remains an interesting problem. Then, the pore size distribution can be obtained from the measurement of the total flow rate as a function of the imposed pressure gradient. Using some yield-pseudo-plastic fluid, the mathematical processing of experimental data should give an insight of the pore-size distribution of the studied porous material. The present technique was successfully tested analytically and numerically for classical pore size distributions such as the Gaussian and the bimodal distributions using Bingham or Casson fluids (the technique was also successfully extended to Herschel-Bulkley fluids but the results are not presented in this paper). The simplicity and the cheapness of this method are also its assets.

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