Thermodynamic Properties of Water in Compacted Bentonite Under External Pressure-free Conditions

1994 ◽  
Vol 353 ◽  
Author(s):  
Yuji Torikai ◽  
Seichi Sato ◽  
Hiroshi Ohashi
Keyword(s):  
Thermodynamic Properties ◽  
Water Content ◽  
Pure Water ◽  
Bound Water ◽  
Free Water ◽  
External Pressure ◽  
Dry Density ◽  
X Ray Diffraction ◽  
Molar Gibbs Free Energy ◽  
Compacted Bentonite

AbstractIn an attempt to determine the thermodynamic properties of water in bentonite, the vapor pressure of water in compacted bentonite was measured as functions of water content and temperature, under external pressure-free conditions. The relative partial molar Gibbs free energy ΔGH2O, enthalpy ΔHH2Oand entropy ΔSH2O of tne waler in bentonite were determined at temperature of 298.15K. The interlayer distance of montmorillonite in bentonite was also measured by X-ray diffraction.It is probable that one fourth of the total water included in the bentonite at water content of 20.3wt% and dry density of 1.76 × 103kg/m3 is nearly free water; the water is not regarded as dilute electrolytic solution but the solution with higher ionic strength. Another one fourth of the water in the bentonite at the water content is bound water; the partial molar entropy of the bound water referred to pure water is from a half to whole of solidification entropy of pure water. The remainder is regarded as intermediately bound water.

Characterization of thin water layers in pulp by tritium exchange. Part 1: Methods development

Holzforschung ◽  
2007 ◽  
Vol 61 (2) ◽  
pp. 115-119 ◽  
Author(s):  
Frances L. Walsh ◽  
Sujit Banerjee
Keyword(s):  
Water Content ◽  
Surface Area ◽  
Tritiated Water ◽  
Bound Water ◽  
Free Water ◽  
Fiber Surface ◽  
Bulk Water ◽  
Methods Development ◽  
A Value ◽  
A New Technique

Abstract A new technique for measuring the monolayer water content of fiber is presented. Tritiated water is added to a pulp/water suspension, whereupon the tritium partitions between the bulk water and the pulp. In the pulp phase the tritium can exchange with free water, bound water, and with hydroxyl and other protons present in the pulp matrix. The free water in the pulp is then removed by displacement with acetone. The tritium remaining in the pulp is mostly associated with tightly bound water, with a small fraction being tied up with the exchangeable hydrogen in pulp. The procedure provides a value of 10% for the tightly bound water content of hardwood or softwood fiber, either bleached or unbleached. If this water is assumed to cover the fiber surface as a monolayer, then an estimate of the wet surface area of the fiber can be obtained. This estimate compares well with independent measurements of surface area.

Experimental study on swelling characteristics of compacted bentonite

1994 ◽  
Vol 31 (4) ◽  
pp. 478-490 ◽  
Author(s):  
Hideo Komine ◽  
Nobuhide Ogata
Keyword(s):  
Water Content ◽  
Nuclear Waste ◽  
Volumetric Strain ◽  
Swelling Pressure ◽  
Dry Density ◽  
Initial Water Content ◽  
Initial Water ◽  
Compacted Bentonite ◽  
Swelling Characteristics ◽  
High Level

Compacted bentonites are attracting greater attention as back-filling (buffer) materials for repositories of high-level nuclear waste. However, since there are few studies about the swelling characteristics of compacted bentonites, it is first necessary to clarify the fundamental swelling characteristics in detail. For this purpose, various laboratory tests on the swelling deformation and swelling pressure of compacted bentonites were performed and the results analyzed. The following conclusions were drawn from the study. (i) The curve of swelling deformation versus time is strongly dependent on the initial dry density, vertical pressure, and initial water content. The maximum swelling deformation, however, is almost independent of initial water content, and the maximum swelling deformation increases in proportion to the initial dry density, (ii) The maximum swelling pressure increases exponentially with increasing initial dry density, whereas the maximum swelling pressure is almost independent of initial water content. (iii) The swelling mechanism of compacted bentonite was considered on the basis of the swelling behavior of swelling clay particles such as montmorillonite. Furthermore, a model of the swelling characteristics and a new parameter (swelling volumetric strain of montmorillonite), which were able to evaluate the swelling characteristics of compacted bentonite, were proposed. Key words : bentonite, laboratory test, nuclear waste disposal, swelling deformation, swelling pressure.

Influence of Recycled Concrete Powder (RCP) and Recycled Brick Powder (RBP) on the Physical/Mechanical Properties and Durability of Raw Soil

Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1475
Author(s):  
Li’an Zhou ◽  
Yang Liu ◽  
Jiacheng Lu ◽  
Wenjuan Zhou ◽  
Hui Wang
Keyword(s):  
Compressive Strength ◽  
Water Content ◽  
Recycled Concrete ◽  
Dry Density ◽  
X Ray Diffraction ◽  
X Ray ◽  
Freeze Thaw ◽  
Performance Change ◽  
Brick Powder ◽  
Research Findings

The influence of recycled concrete powder (RCP) and recycled brick powder (RBP) on the dry density, optimal water content, and compressive strength of raw soil materials was investigated in this study. Moreover, the following resistance of freeze–thaw cycles was also considered. Additionally, X-ray diffraction (XRD) and scanning electron microscope (SEM) were selected to detect its mineral composition and observe the microstructure, further revealing the mechanism of performance change. The mass ratios of recycled concrete powder and recycled brick powder were 2% ~ 14%. Results showed that the dry density decreased and the optimal water content increased with the increasing dosage of recycled concrete powder and recycled brick powder. When the dosage of RCP or RBP was lower than 14%, raw soil with RCP showed higher optimal water content and lower dry density. However, when the dosage was higher than 14%, the result was the opposite. The addition of recycled concrete powder and recycled brick powder was able to decrease the compressive strength of raw soil, except for 10% of recycled brick powder. Raw soil with recycled brick powder presented higher compressive strength than that of raw soil with recycled concrete powder. RBP could improve the freeze–thaw cycles’ resistance of specimens; however, RCP led to decreasing the resistance of freeze–thaw cycles. These research findings can provide reference to the recycling of construction waste.

Natural and Treated Hectorites/Poly(Sodium Acrylate) Hybrids: Synthesis, Characterization, and Properties

2010 ◽  
Vol 63 (10) ◽  
pp. 1462
Author(s):  
Antonio E. Mucientes ◽  
Francisca Santiago ◽  
Ana Carrero ◽  
Carlos Rivera
Keyword(s):  
Bound Water ◽  
Free Water ◽  
Clay Content ◽  
Sodium Acrylate ◽  
Swelling Kinetics ◽  
X Ray Diffraction ◽  
Transmission Electron Microscopy Analysis ◽  
Water Desorption ◽  
Transmission Electron ◽  
Electron Microscopy Analysis

Novel hybrids of poly(sodium acrylate) and natural and treated hectorites have been synthesized and characterized by X-ray diffraction, transmission electron microscopy analysis, and FTIR analysis. The thermal stability of these materials was studied. The swelling kinetics obey a Voigt-based equation. The experimental equilibrium water absorbency varies with the clay content and shows a minimum. All the hybrids showed excellent reswelling capability. Water desorption studies demonstrated the existence of ‘free water’ and ‘bound water’ within the polymeric matrix.

Influence of dry density and water content on the swelling of a compacted bentonite

2008 ◽  
Vol 39 (1-2) ◽  
pp. 38-49 ◽  
Author(s):  
M. Victoria Villar ◽  
Antonio Lloret
Keyword(s):  
Water Content ◽  
Dry Density ◽  
Compacted Bentonite

Experimental Study on Temperature Effect on Engineering Properties of Clayey Soils

2012 ◽  
Vol 512-515 ◽  
pp. 1905-1918
Author(s):  
Yu Xian Shao ◽  
Bin Shi ◽  
Chun Liu ◽  
Lei Gao
Keyword(s):  
Shear Strength ◽  
Temperature Effect ◽  
Water Content ◽  
Free Water ◽  
Adsorbed Water ◽  
Liquid Limit ◽  
Engineering Properties ◽  
Dry Density ◽  
Clayey Soils ◽  
Increasing Temperature

Temperature significantly influences the engineering properties of clayey soil and this temperature effect usually depends on soil type. In this investigation, laboratorial experiments were conducted on three soils to evaluate the adsorbed water content, Atterberg limits, swelling, shear strength and permeability under different temperatures (5-50°C). The results indicate that liquid limit decreases, swelling increases, permeability increases with increasing temperature. It is fundamentally due to the change of adsorbed water content. Hydrophilic minerals, which contain large amounts of adsorbed water, play an important role in the temperature effect. With the increase of hydrophilic minerals, the temperature effect on liquid limit increases and the effect on swelling ratio decreases. The hydrophilic minerals content also has significant impact on the temperature effect of permeability. With increasing temperature, the adsorbed water is transformed to free water, and then the permeability may increase significantly. The shear strength of clayey soils with higher content of hydrophilic mineral is more sensitive to temperature variation. The cohesive force mainly changes linearly with the temperature. Different phenomena, i.e. thermal-hardening or thermal-softening, was observed on strength behaviour due to different hydrophilic mineral content, moisture content and dry density of sample.

scholarly journals Total and Fractional Composition of Water in Pear Leaves Depending on the Optimised Fertiliser

2021 ◽  
Vol 24 (3) ◽  
pp. 45-51
Author(s):  
Roman Yakovenko
Keyword(s):  
Water Content ◽  
Fractional Composition ◽  
Physiological State ◽  
Bound Water ◽  
Free Water ◽  
Practical Significance ◽  
Total Water Content ◽  
Total Water ◽  
Important Indicator ◽  
Positive Effect

The water content in tissues is an important indicator of the physiological state of the plant and is of great importance in the comparative assessment of their cultivation measures that increase productivity. One of such measures is rational fertilisation of plantings, which determines the relevance of the study. The purpose of the study was to establish the effect of optimised fertiliser on the water content in pear tree leaves and the fractional composition of water during stressful growing periods. One of the critical problems is drought, which negatively affects the growth and productivity of plantings. Under such conditions, the turgor of plant cells decreases and the passage of biochemical and physiological processes in the plant slows down. The paper considers the results of studying the water regime of leaves (the content of total, available, and inaccessible moisture) of pear varieties Konferentsia and Osnovianska on vegetative rootstock Quince A grown using optimised fertiliser in nonirrigated plantations. The study was conducted in 2011 and 2018 in a certified educational and research laboratory of the Uman National University of Horticulture. It was found that during the age periods of growth and fruiting, there was a change in the total water content in the pear leaves of the studied varieties. Leaves from pear trees of the Konferentsia variety had a higher water content compared to the Osnovianska variety. Fertiliser options increased the total water content in the leaves, which had a positive effect on the condition of the trees. It was found that at the beginning of the growing season, the free water content in the leaves of pear varieties Konferentsia and Osnovianska was higher, while it significantly decreased in the middle of the season. The bound water content was higher in all studied options. Under stressful situations (drought, temperature increase), fertiliser application had a positive effect on the water content in the leaves of both studied pear varieties. The practical significance of the study is to recommend the production of a rational fertiliser system for nonirrigated pear plantations in different age periods of growth and fruiting, which positively affected the water content in leaves and the fractional composition of water during stressful periods of cultivation

Analysis on Unfrozen Water Content of Mohe Permafrost Based on NMR Method

2014 ◽  
Vol 881-883 ◽  
pp. 1185-1188
Author(s):  
Hao Lin Yu ◽  
Wei Wang ◽  
Yuan Shun Ma ◽  
Xue Yan Xu
Keyword(s):  
Water Content ◽  
Bound Water ◽  
Free Water ◽  
Physical And Mechanical Properties ◽  
Frozen Soil ◽  
Unfrozen Water ◽  
Nmr Method ◽  
Unfrozen Water Content ◽  
Ice Content ◽  
Function Relationship

Unfrozen water content has an important influence on the physical and mechanical properties of frozen soil. Little research has been done on unfrozen water content of permafrost in the Northeast Region, China, so the experimental investigation was performed on Mohe permafrost (4 kinds of samples were taken from 4 kinds of undisturbed frozen soil) based on NMR method, and the relationship and between frozen temperatures (-1°C, -4°C, -7°C, -11°C, -14°C, -16°C) and unfrozen water content was obtained. The test results indicate that, Unfrozen water content decreased with the reduction of frozen temperature of permafrost and there was a power function relationship between unfrozen water content and frozen temperature. The unfrozen water content reduction of No.3 sample was the slowest, because it had the lowest water content and the least frost-heave and thawed amount. It also can be attained that ice content of Mohe permafrost became more and more, but bound water and free water content got less and less while frozen temperature fell continuously.

scholarly journals Solubilization of Methylene Blue in Reversed Micelles, Effect of Water

1980 ◽  
Vol 35 (6) ◽  
pp. 741-745 ◽  
Author(s):  
Norio Miyoshi ◽  
Giiti Tomita
Keyword(s):  
Methylene Blue ◽  
Water Content ◽  
Bound Water ◽  
Free Water ◽  
Reversed Micelles ◽  
Absorption Bands ◽  
Effect Of Water ◽  
Head Groups

Abstract The solubilization of methylene blue in dodecylammonium propionate reversed micelles in cyclohexane depended strongly on the solubilized water content. Methylene blue solubilized in the micelle of which head groups are not completely hydrated by bound water exhibited the new absorption bands at 495 and 270 nm, but these bands did not appear in the micelle containing free water. This dye had the absorption bands at 655 and 290 nm in the latter micelle. The solubilizing process and solubilized state of methylene blue in the reversed micelles were discussed with results obtained.

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