Effects of water content and temperature on the surface conductivity of bentonite clay

Soil Research ◽  
2012 ◽  
Vol 50 (1) ◽  
pp. 44 ◽  
Author(s):  
M. A. Mojid ◽  
H. Cho
Keyword(s):  
Water Content ◽  
Bentonite Clay ◽  
Ionic Mobility ◽  
Surface Conductivity ◽  
Temperature Correction ◽  
Hydration Layer ◽  
Temperature Range ◽  
Wide Range ◽  
Hydration Layers ◽  
Water Contents

This study explored the effects of water content and temperature on the mobility of exchangeable cations (termed the surface ionic mobility and hereafter ionic mobility) in the hydration layers of bentonite clay. The ionic mobility directly governs the surface conductivity of the clay. The investigation was done by measuring the bulk electrical conductivity (EC) of four sand–bentonite mixtures of different proportions for a wide range of water contents under constant temperature, and three bentonite samples at different water contents over 5–90°C. The ionic mobility was determined from the surface conductivity at the mean ionic strength of the hydration layers. The ionic mobility in the sand–bentonite samples increased with an increase in hydration layer thickness. For a given thickness of the hydration layer, the greater the bentonite content of a sample, the smaller was the ionic mobility. The ionic mobility in the bentonite samples at different water contents also increased, at reduced rates, with a rise in temperature. Consequently, the surface conductivity of the samples increased non-uniformly, at two different rates, with an increase in temperature. The increasing rate of this conductivity depended on temperature; over the low temperature range which depended on the water content, the rate was 0.013 dS/m.K, and over higher temperature range, the rate decreased to 0.008 dS/m.K. The commonly used temperature correction factor, 0.019 dS/m.K, for EC therefore did not hold true for the bentonite samples.

WATER TOLERANCE OF MIXTURES OF GASOLINE WITH ETHYL ALCOHOL, ISOPROPYL ALCOHOL AND BENZENE

1934 ◽  
Vol 11 (4) ◽  
pp. 505-519
Author(s):  
Colin H. Bayley ◽  
Clarence Yardley Hopkins
Keyword(s):  
Water Content ◽  
Ethyl Alcohol ◽  
Isopropyl Alcohol ◽  
The Other ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Water Tolerance ◽  
Wide Range ◽  
Critical Water Content ◽  
Water Contents

The relation between water content and critical solution temperature of mixtures of gasoline with ethanol and isopropanol and with ethanol and benzene has been determined. Curves are presented which show the critical water contents of a wide range of mixtures at any temperature between + 20° and − 50 °C. Three gasolines were used, two being straight-run and one a cracked gasoline. The mixtures contained 60 to 90% of gasoline with varying proportions of the other two components. Isopropanol has been found to bring about a marked increase in the critical water content of gasoline-ethanol mixtures to which it is added. Benzene is shown to be of little value for this purpose within the range of mixtures studied.

ANALYSIS OF EMPIRICAL COMPRESSION INDEX EQUATIONS USING THE WATER CONTENT

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Amir W. Al-Khafaji ◽  
Krishnanand Y. Maillacheruvu ◽  
Melissa Hoerber
Keyword(s):  
Water Content ◽  
Empirical Models ◽  
Soil Types ◽  
Data Sets ◽  
Regression Equations ◽  
Compression Index ◽  
Empirical Formulas ◽  
Wide Range ◽  
Compression Data ◽  
Water Contents

This paper proposes a new method to evaluate the reliability of published empirical formulas in terms of accuracy and applicability to different soil types. Different empirical models are proposed to properly approximate the compression index for a wide range of water contents and soil types. They were developed using a unique technique and a substantial number of published regression equations and compression data. Familiar empirical equations were examined for their reliability in predicting the compression index of clay for any water content. A comparison was made between available and newly-proposed empirical formulas using combined regression data sets compiled independently by several authors. The newly proposed empirical compression index equations are applicable to a wide range of clay soils, and in validating other published relationships. The degree of scatter and variations in the computed compression index values are minimized for any water content.

Seed mass variation potentially masks a single critical water content in recalcitrant seeds

2004 ◽  
Vol 14 (2) ◽  
pp. 185-195 ◽  
Author(s):  
Matthew I. Daws ◽  
Christiane S. Gaméné ◽  
Sheila M. Glidewell ◽  
Hugh W. Pritchard
Keyword(s):  
Water Content ◽  
Seed Mass ◽  
Tropical Tree ◽  
Recalcitrant Seeds ◽  
Seed Population ◽  
Wide Range ◽  
Critical Water Content ◽  
Whole Seed ◽  
Water Contents ◽  
Seed Water Content

For recalcitrant seeds, mortality curves of germination versus water content typically imply a wide range of desiccation sensitivities within a seed population. However, seed to seed differences in water content, during desiccation, may confound our interpretation of these mortality plots. Here, we illustrate this problem for two batches ofVitellaria paradoxa(Sapotaceae) seeds collected in 1996 and 2002. Whole seeds were desiccated to various target water contents (TWCs) using silica gel. During desiccation, smaller seeds in the population dried most rapidly. Consequently, there was a significant linear relationship between whole-seed water content and seed mass during the drying process. In addition, following desiccation to low TWCs, only the largest seeds in the population retained viability. Taken together, this suggests that the larger seeds survived, not as a consequence of great relative desiccation tolerance, but as a result of taking longer to desiccate. Subsequently, the critical water content (CWC) for viability loss was calculated, based on the assumptions that in the seed population whole-seed water content during desiccation was normally distributed and the smallest, and hence driest, seeds were killed first. Using this approach, the driest seeds in the population that were killed, at each TWC, were always below a single CWC (c. 20% and 26% in 1996 and 2002, respectively). In subsequent experiments the effect of seed size variation on the response to desiccation was confirmed by conducting desiccation screens on seeds sorted into two discrete size classes, i.e. the seed-lot heterogeneity in mass was reduced. Using this approach, the mortality curves had a steeper slope. Furthermore, data for 24 tropical tree species from the Database of Tropical Tree Seed Research (DABATTS) revealed that seed lots with less variability in mass had steeper mortality curves. Thus, taken together, the data suggest that, at least for whole seeds, the wide range of desiccation sensitivities typically inferred is an artefact of seed to seed variation in mass, and hence water contents, during drying.

A model for collagen hydration

1971 ◽  
Vol 178 (1053) ◽  
pp. 465-476 ◽  
Keyword(s):  
High Water ◽  
Nuclear Magnetic Resonance Study ◽  
Proton Nuclear Magnetic Resonance ◽  
Collagen Molecule ◽  
Water Molecules ◽  
Hydration Layer ◽  
Collagen Molecules ◽  
Hydration Layers ◽  
Rate Dynamic ◽  
Water Contents

A detailed proton nuclear magnetic resonance study has been made of the influence of temperature and water content upon the nature of water adsorbed on collagen fibres. A refinement of a previously reported analysis of time-averaged tensor properties of the water molecule with respect to the fibre axis supports the previous conclusion that the water molecules form hydrogen-bonded chains around the collagen molecules. The experimental evidence strongly indicates that there is an inner hydration layer consisting of about 24 % water per weight of dry collagen, which is highly ordered, surrounded by a disordered outer layer of water at high-water contents. Exchange of water molecules between the inner and outer hydration layers takes place at a rapid rate. Dynamic aspects of the hydration structure are discussed, and it is suggested that the inner hydration layer imparts an appreciable degree of kinetic stability to the native conformation of the collagen molecule.

Water Diffusion in Silicate Glasses and Melts

2006 ◽  
Vol 46 ◽  
pp. 79-88 ◽  
Author(s):  
Harald Behrens
Keyword(s):  
Water Content ◽  
Ambient Pressure ◽  
High Water ◽  
Float Glass ◽  
Water Diffusion ◽  
Experimental Investigations ◽  
Melt Structure ◽  
Water Diffusivity ◽  
Wide Range ◽  
Water Contents

Knowledge on diffusion of water in glasses and melts is important for glass sciences as well as for Earth sciences. The ranges of water contents differ widely in both research domains. Industrial glass contain typically less than 0.1 wt% H2O whereas natural glasses may even contain up to 10 wt% H2O. Dissolved water strongly modifies physical and chemical properties of the melts and, hence, water diffusion studies at low water contents often cannot be transferred to high water contents and vice versa. Pressure effect on water diffusion, on the other hand, is small so that high pressure data can be applied also at ambient pressure without significant error. At low water contents the assumption of constant water diffusivity is often justified whereas at high water contents the H2O diffusivity increases strongly (often linearly or exponentially) with water content. Combining experimental data over a wide range of water contents allows getting deeper understanding of the mechanisms of water diffusion and of the effect of dissolved water on melt structure. In this paper an overview is given on experimental investigations on water diffusivity in aluminosilicate and silicate systems. Effects of base compositions and water content on water diffusivities are discussed. New experimental results for water diffusion in soda lime silica glass, float glass and borosilicate glass are presented.

Determining the virgin compression lines of reconstituted clays at different initial water contents

2015 ◽  
Vol 52 (9) ◽  
pp. 1408-1415 ◽  
Author(s):  
Ling-Ling Zeng ◽  
Zhen-Shun Hong ◽  
Yu-Jun Cui
Keyword(s):  
Regression Analysis ◽  
Water Content ◽  
Liquid Limit ◽  
Initial Water Content ◽  
Initial Water ◽  
Kaolinite Clay ◽  
Soil Particles ◽  
Wide Range ◽  
Natural Clays ◽  
Water Contents

Forty-eight consolidometer tests were performed on various natural clays and a kaolinite clay reconstituted in the laboratory at different initial water contents using a modified consolidometer apparatus. These data together with those published previously allow a multi-regression analysis for the development of an approach for determining the intrinsic compression parameters that depend on initial water content and liquid limit. The approach proposed by Burland can be thereby extended to provide an expression describing the compression response of a wide range of clays. Based on the intrinsic concept, a simple way of determining the virgin compression lines of reconstituted clays is also proposed using the density of soil particles, initial water content, and liquid limit.

A review of the composition and evolution of hydrocarbon gases during solidification of the Ilímaussaq alkaline complex, South Greenland

2001 ◽  
pp. 159-166 ◽  
Author(s):  
Jens Konnerup-Madsen
Keyword(s):  
Nepheline Syenite ◽  
Subsequent Development ◽  
High Water ◽  
Vapour Phase ◽  
Low Carbon ◽  
Low Oxygen ◽  
Alkaline Complex ◽  
Hydrocarbon Gases ◽  
Wide Range ◽  
Water Contents

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Konnerup-Madsen, J. (2001). A review of the composition and evolution of hydrocarbon gases during solidification of the Ilímaussaq alkaline complex, South Greenland. Geology of Greenland Survey Bulletin, 190, 159-166. https://doi.org/10.34194/ggub.v190.5187 _______________ Fluid inclusions in minerals from agpaitic nepheline syenites and hydrothermal veins in the Ilímaussaq complex and in similar agpaitic complexes on the Kola Peninsula, Russia, are dominated by hydrocarbon gases (predominantly methane) and hydrogen. Such volatile compositions differ considerably from those of most other igneous rocks and their formation and entrapment in minerals reflects low oxygen fugacities and a wide range of crystallisation temperatures extending to a low-temperature solidus. Their composition reflects initial low carbon contents and high water contents of the magma resulting in the exsolution of a waterrich CO2–H2O dominated vapour phase. Fractionation of chlorides into the vapour phase results in high salinities and the subsequent development of a heterogeneous vapour phase with a highly saline aqueous-rich fraction and a methane-dominated fraction, with preferential entrapment of the latter, possibly due to different wetting characteristics. The light stable isotope compositions support an abiogenic origin for the hydrocarbons in agpaitic nepheline syenite complexes.

Soil Mixer for a Wide Range of Water Contents

1990 ◽  
Vol 54 (2) ◽  
pp. 555-557 ◽  
Author(s):  
Ralph G. Nash ◽  
M. Leroy Beall
Keyword(s):  
Wide Range ◽  
Water Contents

Enabling highly reversible sodium metal cycling across a wide temperature range with dual-salt electrolytes

2021 ◽  
Author(s):  
Akila C. Thenuwara ◽  
Pralav P. Shetty ◽  
Neha Kondekar ◽  
Chuanlong Wang ◽  
Weiyang Li ◽  
...  
Keyword(s):  
Wide Temperature Range ◽  
High Energy ◽  
Liquid Electrolyte ◽  
Metal Cycling ◽  
Temperature Range ◽  
Sodium Metal ◽  
Wide Range

A new dual-salt liquid electrolyte is developed that enables the reversible operation of high-energy sodium-metal-based batteries over a wide range of temperatures down to −50 °C.

scholarly journals Multidimensional Ln-Aminophthalate Photoluminescent Coordination Polymers

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1786
Author(s):  
Carla Queirós ◽  
Chen Sun ◽  
Ana M. G. Silva ◽  
Baltazar de Castro ◽  
Juan Cabanillas-Gonzalez ◽  
...  
Keyword(s):  
Water Content ◽  
Coordination Polymers ◽  
Metal Ion ◽  
Low Cost ◽  
Microwave Assisted Synthesis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wide Range ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

The development of straightforward reproducible methods for the preparation of new photoluminescent coordination polymers (CPs) is an important goal in luminescence and chemical sensing fields. Isophthalic acid derivatives have been reported for a wide range of applications, and in addition to their relatively low cost, have encouraged its use in the preparation of novel lanthanide-based coordination polymers (LnCPs). Considering that the photoluminescent properties of these CPs are highly dependent on the existence of water molecules in the crystal structure, our research efforts are now focused on the preparation of CP with the lowest water content possible, while considering a green chemistry approach. One- and two-dimensional (1D and 2D) LnCPs were prepared from 5-aminoisophthalic acid and Sm3+/Tb3+ using hydrothermal and/or microwave-assisted synthesis. The unprecedented LnCPs were characterized by single-crystal X-ray diffraction (SCRXD), powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM), and their photoluminescence (PL) properties were studied in the solid state, at room temperature, using the CPs as powders and encapsulated in poly(methyl methacrylate (PMMA) films, envisaging the potential preparation of devices for sensing. The materials revealed interesting PL properties that depend on the dimensionality, metal ion, co-ligand used and water content.

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