PORE SIZE DISTRIBUTION IN CRITICAL POINT AND FREEZE DRIED AGGREGATES FROM CLAY SUBSOILS

1979 ◽  
Vol 30 (3) ◽  
pp. 499-516 ◽  
Author(s):  
G. P. LAWRENCE ◽  
D. PAYNE ◽  
D. J. GREENLAND
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Critical Point ◽  
Size Distribution ◽  
Freeze Dried

scholarly journals Experimental investigation on pore size distribution and drying kinetics during lyophilization of sugar solutions

2018 ◽  
Author(s):  
Petra Foerst ◽  
M. Lechner ◽  
N. Vorhauer ◽  
H. Schuchmann ◽  
E. Tsotsas
Keyword(s):  
Pore Structure ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Freeze Drying ◽  
Three Dimensional ◽  
Drying Kinetics ◽  
Process Efficiency ◽  
Freeze Dried ◽  
Pore Size Distributions

The pore structure is a decisive factor for the process efficiency and product quality of freeze dried products. In this work the two-dimensional ice crystal structure was investigated for maltodextrin solutions with different concentrations by a freeze drying microscope. The resulting drying kinetics was investigated for different pore structures. Additionally the three-dimensional pore structure of the freeze dried samples was measured by µ-computed tomography and the pore size distribution was quantified by image analysis techniques. The two- and three-dimensional pore size distributions were compared and linked to the drying kinetics.Keywords: pore size distribution; freeze drying; maltodextrin solution; freeze drying microscope   

Fractal pore-size distribution on freeze-dried agar-texturized fruit surfaces

2004 ◽  
Vol 18 (5) ◽  
pp. 825-835 ◽  
Author(s):  
A. Nussinovitch ◽  
N. Jaffe ◽  
M. Gillilov
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Freeze Dried

Measuring and predicting pore size distribution of freeze-dried solutions

2018 ◽  
Vol 37 (4) ◽  
pp. 435-447 ◽  
Author(s):  
A. Arsiccio ◽  
A. C. Sparavigna ◽  
R. Pisano ◽  
A. A. Barresi
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Freeze Dried

Frost-heaving rate predicted from pore-size distribution

1979 ◽  
Vol 16 (3) ◽  
pp. 463-472 ◽  
Author(s):  
M. A. Reed ◽  
C. W. Lovell ◽  
A. G. Altschaeffl ◽  
L. E. Wood
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Energy Levels ◽  
Frost Heave ◽  
Compacted Soils ◽  
Freeze Dried ◽  
Pore Size Distributions ◽  
Silty Soils ◽  
Water Contents

The purpose of this study was to examine the relation of frost heave to pore-size distribution of compacted silty soils, and to propose that frost-susceptibility criteria based upon the distribution of porosity are more logical and versatile than those based upon texture and grain size.Rapid freezing laboratory tests were conducted to evaluate the heaving rate. The soils were compacted at different energy levels and water contents, and consisted of three different combinations of silt and kaolin.Mercury intrusion tests were performed to obtain the pore-size distributions of the compacted soils. Since this procedure requires the soil to be free of moisture, the soil samples were freeze-dried. This type of drying minimized the volume change and consequent structural modification expected from air or oven drying.The relation of frost heave to pore size was obtained using the method of linear regression. For a given soil, it is the quantity of interaggregate pores that controls the frost heave. These pores are, in turn, controlled by the compaction variables of water content and effort.

scholarly journals Identifying thermo-mechanical induced microstructural changes

2020 ◽  
Vol 205 ◽  
pp. 09005
Author(s):  
Seyed Morteza Zeinali ◽  
Sherif L. Abdelaziz
Keyword(s):  
Specific Surface ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Surface Area ◽  
Specific Surface Area ◽  
Temperature Cycle ◽  
Clear Understanding ◽  
Microstructural Changes ◽  
Freeze Dried

Robust engineering of geomaterials for energy applications requires a clear understanding of the impacts of temperatures and pressures applied to the soil on their microstructures. Such understandings will facilitate better designs of new geomaterials and technologies via ensuring accurate assessments of the performance of the existing ones. In this study, we assess the changes in the microstructure—specific surface area and pore size distribution—of a saturated clay subjected to stress and temperature cycle. Clay specimens were subjected to the desired mechanical stresses and thermal cycles in a triaxial system. Then, the specimens were swiftly extracted from the triaxial, flush frozen in liquid nitrogen, then freeze-dried to preserve their microstructure. The preserved specimens were then used for specific surface area and pore size distribution assessments using nitrogen (N2)-gas adsorption and mercury intrusion porosimetry. The results established qualitative explanations of the expected microstructural changes in geomaterials under operational conditions, which facilitate the development of new geomaterials that can overcome such alternations.

Effect of air-drying and critical point drying on the porosity of clay soils

1984 ◽  
Vol 21 (1) ◽  
pp. 181-185 ◽  
Author(s):  
C. R. De Kimpe
Keyword(s):  
Organic Matter ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Critical Point ◽  
Size Distribution ◽  
Pore Volume ◽  
Organic Matter Content ◽  
Total Pore Volume ◽  
Clay Soils ◽  
Critical Point Drying

Samples from four surface and one subsurface horizons of clay-rich soils from Quebec were air-dried and critical point dried. In the latter samples, the total pore volume was 19–84% larger than in the former samples. The total pore volume, determined by mercury intrusion porosimetry and density measurements, was subdivided into large (> 8.8 μm), medium, and small (< 0.19 μm) pores. The effect of drying on these pores was estimated. Medium-sized pores were affected most by the drying technique, followed next by the large pores, and finally by the small pores. The modifications due to drying could not be explained adequately by shrinkage and it was assumed, from the pore-size distribution curves, that organic matter content had a buffer effect on particle reorganization. Keywords: critical point drying, clay soils, pore volume, pore-size distribution, organic matter.

Change in pore size distribution owing to secondary consolidation of clays

1991 ◽  
Vol 28 (1) ◽  
pp. 20-24 ◽  
Author(s):  
Fred J. Griffiths ◽  
Ramesh C. Joshi
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Key Words ◽  
Size Distribution ◽  
Mercury Intrusion Porosimetry ◽  
Soil Types ◽  
Clayey Soils ◽  
Mercury Intrusion ◽  
Fabric Structure ◽  
Freeze Dried

The preliminary results of a study using mercury-intrusion porosimetry on freeze-dried samples of clayey soils are presented. The amount of secondary consolidation has been varied for several samples of three soil types by holding the consolidation stress steady at 120 kPa for different durations. Examination of the pore size distribution curves reveals that secondary consolidation cannot be due solely to the deformation of micropores. The relative degree of change in total, free and entrapped porosity appears to be related to the proportion of each initially in the sample. Key words: clays, consolidation, compressibility, fabric-structure of soils, secondary compression.

Compressibility effect in evaluating the pore-size distribution of kaolin clay using mercury intrusion porosimetry

2000 ◽  
Vol 37 (2) ◽  
pp. 393-405 ◽  
Author(s):  
Dayakar Penumadu ◽  
John Dean
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Mercury Intrusion Porosimetry ◽  
Sessile Drop ◽  
Kaolin Clay ◽  
Scanning Electron Micrographs ◽  
Test Results ◽  
Mercury Intrusion ◽  
Freeze Dried

The objective of the present research is to quantitatively evaluate the compression that can occur during the evaluation of pore-size distribution of cohesive soil using mercury intrusion porosimetry (MIP). A new experimental procedure was developed that can be routinely used to evaluate the corrections associated with the compressibility for porous solid samples using MIP. The approach used in this study involves performing mercury intrusion tests on dehydrated kaolin samples using freeze-dried and oven-dried techniques, and on identical samples confined by low-porosity latex membranes. Corrections for latex intrusion and issues related to dehydration of samples are addressed. The measured contact angle of mercury with kaolin clay using the sessile drop technique was used in the data reduction. Repeatable test results were obtained throughout the testing program. The procedure for obtaining volume-change behavior under isotropic conditions for a large range of pressures using the mercury porosimeter is also presented for oven-dried samples. Scanning electron micrographs for intruded and compressed specimens are presented along with a discussion on the observed hysteresis in MIP test data. The test results for kaolin samples show substantive initial compression before the occurrence of actual intrusion. This resulted in errors associated with the interpretation of pore sizes with diameters in the range of 0.4-200 µm.Key words: mercury intrusion, clay, compression, correction, pore-size distribution, high pressure.

pyGAPS: A Python-Based Framework for Adsorption Isotherm Processing and Material Characterisation

2019 ◽  
Author(s):  
Paul Iacomi ◽  
Philip L. Llewellyn
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Surface Area ◽  
Isosteric Heat ◽  
Material Characterisation ◽  
Mixture Adsorption ◽  
Surface Energetics ◽  
Adsorption Processing ◽  
User Friendly

Material characterisation through adsorption is a widely-used laboratory technique. The isotherms obtained through volumetric or gravimetric experiments impart insight through their features but can also be analysed to determine material characteristics such as specific surface area, pore size distribution, surface energetics, or used for predicting mixture adsorption. The pyGAPS (python General Adsorption Processing Suite) framework was developed to address the need for high-throughput processing of such adsorption data, independent of the origin, while also being capable of presenting individual results in a user-friendly manner. It contains many common characterisation methods such as: BET and Langmuir surface area, t and α plots, pore size distribution calculations (BJH, Dollimore-Heal, Horvath-Kawazoe, DFT/NLDFT kernel fitting), isosteric heat calculations, IAST calculations, isotherm modelling and more, as well as the ability to import and store data from Excel, CSV, JSON and sqlite databases. In this work, a description of the capabilities of pyGAPS is presented. The code is then be used in two case studies: a routine characterisation of a UiO-66(Zr) sample and in the processing of an adsorption dataset of a commercial carbon (Takeda 5A) for applications in gas separation.

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