The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Lucas Martin - One of the best experts on this subject based on the ideXlab platform.
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In-Situ Determination of Specific Surface Area of Clays
Geotechnical and Geological Engineering, 2019Co-Authors: Jay N. Meegoda, Lucas MartinAbstract:There are many methods to determine the Specific Surface Area (SSA) of clay minerals. Some of these methods lack accuracy and some are time consuming. There are no methods available for the determination of in situ SSA. In this paper a new approach to predict the SSA of clays is proposed, which has been verified in the laboratory. This method is based on the electrical properties of soils. In this paper the experimental set up and the estimation of Specific Surface Area is presented on the basis of variation of the dielectric constant and the conductivity of the clay–water system when subjected to alternating current in the frequency range of 1–100 MHz. The dielectric constant and conductivity respond differently for different soils with varying Surface Area corresponding to their mineralogy. When dielectric constants and conductivity were measured for sandy soils, there were no effects with the change of input frequency. The electrical method can identify clays and separate them from fine grained silts. Data are presented which shows a linear correlation between the magnitude of dielectric dispersion and SSA for various clay mixtures. The clay structure determines the value of in situ dielectric dispersion of the clay (Δε_o) and hence the SSA, making this a good in situ method to estimate SSA of clays.
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In-Situ Determination of Specific Surface Area of Clays
Geotechnical and Geological Engineering, 2018Co-Authors: Jay N. Meegoda, Lucas MartinAbstract:There are many methods to determine the Specific Surface Area (SSA) of clay minerals. Some of these methods lack accuracy and some are time consuming. There are no methods available for the determination of in situ SSA. In this paper a new approach to predict the SSA of clays is proposed, which has been verified in the laboratory. This method is based on the electrical properties of soils. In this paper the experimental set up and the estimation of Specific Surface Area is presented on the basis of variation of the dielectric constant and the conductivity of the clay–water system when subjected to alternating current in the frequency range of 1–100 MHz. The dielectric constant and conductivity respond differently for different soils with varying Surface Area corresponding to their mineralogy. When dielectric constants and conductivity were measured for sandy soils, there were no effects with the change of input frequency. The electrical method can identify clays and separate them from fine grained silts. Data are presented which shows a linear correlation between the magnitude of dielectric dispersion and SSA for various clay mixtures. The clay structure determines the value of in situ dielectric dispersion of the clay (Δeo) and hence the SSA, making this a good in situ method to estimate SSA of clays.
Jay N. Meegoda - One of the best experts on this subject based on the ideXlab platform.
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In-Situ Determination of Specific Surface Area of Clays
Geotechnical and Geological Engineering, 2019Co-Authors: Jay N. Meegoda, Lucas MartinAbstract:There are many methods to determine the Specific Surface Area (SSA) of clay minerals. Some of these methods lack accuracy and some are time consuming. There are no methods available for the determination of in situ SSA. In this paper a new approach to predict the SSA of clays is proposed, which has been verified in the laboratory. This method is based on the electrical properties of soils. In this paper the experimental set up and the estimation of Specific Surface Area is presented on the basis of variation of the dielectric constant and the conductivity of the clay–water system when subjected to alternating current in the frequency range of 1–100 MHz. The dielectric constant and conductivity respond differently for different soils with varying Surface Area corresponding to their mineralogy. When dielectric constants and conductivity were measured for sandy soils, there were no effects with the change of input frequency. The electrical method can identify clays and separate them from fine grained silts. Data are presented which shows a linear correlation between the magnitude of dielectric dispersion and SSA for various clay mixtures. The clay structure determines the value of in situ dielectric dispersion of the clay (Δε_o) and hence the SSA, making this a good in situ method to estimate SSA of clays.
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In-Situ Determination of Specific Surface Area of Clays
Geotechnical and Geological Engineering, 2018Co-Authors: Jay N. Meegoda, Lucas MartinAbstract:There are many methods to determine the Specific Surface Area (SSA) of clay minerals. Some of these methods lack accuracy and some are time consuming. There are no methods available for the determination of in situ SSA. In this paper a new approach to predict the SSA of clays is proposed, which has been verified in the laboratory. This method is based on the electrical properties of soils. In this paper the experimental set up and the estimation of Specific Surface Area is presented on the basis of variation of the dielectric constant and the conductivity of the clay–water system when subjected to alternating current in the frequency range of 1–100 MHz. The dielectric constant and conductivity respond differently for different soils with varying Surface Area corresponding to their mineralogy. When dielectric constants and conductivity were measured for sandy soils, there were no effects with the change of input frequency. The electrical method can identify clays and separate them from fine grained silts. Data are presented which shows a linear correlation between the magnitude of dielectric dispersion and SSA for various clay mixtures. The clay structure determines the value of in situ dielectric dispersion of the clay (Δeo) and hence the SSA, making this a good in situ method to estimate SSA of clays.
Vincent G Gomes - One of the best experts on this subject based on the ideXlab platform.
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preparation and characterization of high Specific Surface Area activated carbons from k2co3 treated waste polyurethane
Journal of Colloid and Interface Science, 2005Co-Authors: Jun'ichi Hayashi, N Yamamoto, Toshihide Horikawa, Katsuhiko Muroyama, Vincent G GomesAbstract:Abstract An activated carbon with high Specific Surface Area was prepared from polyurethane foam by chemical activation with K 2 CO 3 and the influences of carbonization temperature and impregnation ratio on the pore structure of the prepared activated carbon were investigated. It was found that the Specific Surface Area of the activated carbon was at a maximum value (about 2800 m 2 /g) at a carbonization temperature of 1073 K and at an impregnation ratio of 1.0. It was concluded that the polyurethane foam structure was modified during impregnation by K 2 CO 3 , K 2 CO 3 promoted charring during carbonization, and then the weight loss behavior was changed below 700 and above 1000 K, carbon in the char was consumed by K 2 CO 3 reduction, and this led to the high Specific Surface Area. The prepared activated carbon had a very sharp micropore size distribution, compared with the commercial activated carbon having high Specific Surface Area. The amounts of three organic vapors (benzene, acetone, and octane) adsorbed on the prepared activated carbons was much larger than those on the traditional coconut shell AC and the same as those on the commercial activated carbon except for octane. We surmised that the high Specific Surface Area was due to the modification of the carbonization behavior of polyurethane foam by K 2 CO 3 .
Song Mi Lee - One of the best experts on this subject based on the ideXlab platform.
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Surface oxidation of petroleum pitch to improve mesopore ratio and Specific Surface Area of activated carbon
Scientific Reports, 2021Co-Authors: Song Mi Lee, Seon Ho Lee, Doohwan JungAbstract:In this study, Surface oxidation of petroleum pitch was performed to enhance the thermal stability, Specific Surface Area, and mesopore ratio of activated carbon. The oxygen uptake of the pitch by Surface oxidation has a strong influence on the formation of the Specific Surface Area and pore size of activated carbon. It was confirmed that the oxygen uptake from the Surface to the inner side of the Surface oxidized pitch was the highest at the temperature of 330 °C (IP330-AC), with a mesopore ratio of 63.35% and Specific Surface Area of 1811 m2 g-1. The oxygen content of the Surface oxidized pitch increased proportionately with the mesopore ratio in activated carbon. The Specific Surface Area and mesopore ratio of IP330-AC were respectively 163% and 487% higher than those of petroleum-based commercial activated carbon (A-BAC), and 102% and 491% higher than those of coconut-based commercial activated carbon (P60).
Cuong Pham-huu - One of the best experts on this subject based on the ideXlab platform.
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High Specific Surface Area carbides of silicon and transition metals for catalysis
Catalysis Today, 1992Co-Authors: Marc-jacques Ledoux, Cuong Pham-huuAbstract:Abstract A new synthesis of carbides based on the concept of shape memory is summarized. High Specific Surface Area activated carbon is reacted with a vapor of the oxide to give the corresponding high Specific Surface Area carbide and carbon monoxide. Some catalytic applications of these new materials are presented.
