Ultrasonic wave velocities in the structure II clathrate hydrate THF�17H2O

Bathe, Mark; Vagle, Svein; Saunders, G. A.; Lambson, E. F.

doi:10.1007/bf00719584

Cited by 26 publications

(22 citation statements)

References 12 publications

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“…Kiefte et al 75 derived a bulk modulus for THF clathrates ͑type II͒ of 85 kbar at 273 K using Brillouin spectroscopy. Their results are close to those of Bathe et al, 76 giving 82.7 kbar at 256 K determined with ultrasonic techniques although they disagree in their sound velocity ratio v clathrate /v ice . To compare our results with the bulk modulus obtained by Kiefte et al 75 on THF-clathrate one has to convert the adiabatic bulk modulus K S into the isothermal one K T according to: K T Ϫ1 ϭK S Ϫ1 (1ϩ␣ 2 TK S /(c P )).…”

Section: A Lattice Constants and Compressibilitysupporting

confidence: 86%

“…To compare our results with the bulk modulus obtained by Kiefte et al 75 on THF-clathrate one has to convert the adiabatic bulk modulus K S into the isothermal one K T according to: K T Ϫ1 ϭK S Ϫ1 (1ϩ␣ 2 TK S /(c P )). Using 195.5ϫ10 Ϫ6 K Ϫ1 for the thermal expansivity ␣ of THFclathrates derived at 273 K from Tse, 77 1966 J kg Ϫ1 K Ϫ1 for c P the specific heat 78 at 260 K, 0.97 for the density of THF-clathrate, 75 K T is found to be 84.9 kbar at 273 K. From the data of Bathe et al, 76 one derives a K T of 82.6 kbar at 256 K. Even if these values are affected by some uncertainties in the experimentally determined thermodynamic data of c P , , and ␣, it suggests that the K T values obtained are lower than the corresponding value for ice Ih 79 of ϳ90 kbar and lower than the values for air-and O 2 -clathrates. It is tempting to attribute this effect to the low filling of the THF clathrate structure with its empty small cages.…”

Section: A Lattice Constants and Compressibilitymentioning

confidence: 98%

See 1 more Smart Citation

In situ structural properties of N2-, O2-, and air-clathrates by neutron diffraction

Chazallon

Kuhs

2002

The Journal of Chemical Physics

134

126

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Neutron diffraction study of the coupling between spin, lattice, and structural degrees of freedom in 0.8BiFeO3-0.2PbTiO3 J. Appl. Phys. 109, 063522 (2011); 10.1063/1.3555093 Structure and phase transitions of monolayers of intermediate-length n -alkanes on graphite studied by neutron diffraction and molecular dynamics simulationThe crystal structures of type II N 2 -, O 2 -, and air-clathrate hydrates have been studied under their thermodynamic conditions of stability by neutron powder diffraction. The isothermal compressibilities were deduced from the refined lattice constants and found to be significantly different for N 2 and O 2 clathrate hydrates. The water host lattice structure rearranges as a function of pressure with a resulting change of the volume ratio of small and large cages. The cage fillings were established on an absolute scale for the first time. The large cages were found to be partly occupied by two molecules. The results are compared with predictions based on the statistical thermodynamic theory of van der Waals and Platteeuw. While the filling follows the predicted trend significant differences exist in detail.

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Section: A Lattice Constants and Compressibilitysupporting

confidence: 86%

Section: A Lattice Constants and Compressibilitymentioning

confidence: 98%

In situ structural properties of N2-, O2-, and air-clathrates by neutron diffraction

Chazallon

Kuhs

2002

The Journal of Chemical Physics

134

126

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“…[8] Because of the difficulty in forming methane gas hydrate, differing hydrate formers have been used such as propane [Stoll, 1974;Stoll and Bryan, 1979;Stoll et al, 1971], and analogues of natural gas including tetrahydrofuran (THF) [Bathe et al, 1984;Berge et al, 1999;Kiefte et al, 1985;Kunerth et al, 2001;Pearson et al, 1986] and Freon-11 (CCL 3 F) [Berge et al, 1999], all of which require less onerous stability conditions. These compounds form structure II gas hydrates which have different crystal structure to methane hydrate (structure I), which may lead to differing mechanical properties.…”

Section: Hydrate Formationmentioning

confidence: 99%

A laboratory investigation into the seismic velocities of methane gas hydrate‐bearing sand

2005

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[1] Remote seismic methods, which measure the compressional wave (P wave) velocity (V p ) and shear wave (S wave) velocity (V s ), can be used to assess the distribution and concentration of marine gas hydrates in situ. However, interpreting seismic data requires an understanding of the seismic properties of hydrate-bearing sediments, which has proved problematic because of difficulties in recovering intact hydrate-bearing sediment samples and in performing valid laboratory tests. Therefore a dedicated gas hydrate resonant column (GHRC) was developed to allow pressure and temperature conditions suitable for hydrate formation to be applied to a specimen with subsequent measurement of both V p and V s made at frequencies and strains relevant to marine seismic investigations. Thirteen sand specimens containing differing amounts of evenly dispersed hydrate were tested. The results show a bipartite relationship between velocities and hydrate pore saturation, with a marked transition between 3 and 5% hydrate pore saturation for both V p and V s . This suggests that methane hydrate initially cements sand grain contacts then infills the pore space. These results show in detail for the first time, using a resonant column, how hydrate cementation affects elastic wave properties in quartz sand. This information is valuable for validating theoretical models relating seismic wave propagation in marine sediments to hydrate pore saturation.Citation: Priest, J. A., A. I. Best, and C. R. I. Clayton (2005), A laboratory investigation into the seismic velocities of methane gas hydrate-bearing sand,

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“…For methane and xenon, the relative sound velocity of hydrate to ice was 0.88 and 0.76, respectively. Bathe et al [83] presented measured ultrasonic wave velocities in structure II polycrystalline THF hydrate.…”

Section: Seismic Geophysical Methods and Measured Resultsmentioning

confidence: 99%

Advances in Study of Mechanical Properties of Gas Hydrate-Bearing Sediments

鲁晓兵

张旭辉²,

王淑云³

2013

TOOEJ

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Gas hydrate (GH) is defined as the crystalline solid, or clathrate hydrate, which are formed by some kinds of low mass molecular gases, such as methane, carbon dioxide, and hydronitrogen, with water at relatively high pressure and low temperature conditions. Gas hydrate-bearing sediments (HBS) are some sand, clay and mixed sediment containing gas hydrates. Advances in the study on the mechanical properties of HBS are summarized mainly in aspects of the laboratory test, in-situ investigation, and theoretical model. Firstly, the main factors are discussed including the structure of GH, formation method and matrix characteristics of HBS; Secondly, progress on the laboratory tests and results are discussed, which mainly includes the tri-axial tests with the natural and synthesized HBS samples, the acoustic tests for measuring the elastic coefficients, the tests for investigating the effects of main factors such as the gas and water contents and soil types on the strength of HBS. Thirdly, for in-situ investigations, including the geophysical surveying, in-situ tests (such as downhole tests) and results are summarized; Fourthly, several theoretical models for estimating the mechanical properties of HBS are introduced; At last, the emphases and the tendency in the future study on the mechanical properties of HBS are discussed.

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Ultrasonic wave velocities in the structure II clathrate hydrate THF�17H2O

Cited by 26 publications

References 12 publications

In situ structural properties of N2-, O2-, and air-clathrates by neutron diffraction

In situ structural properties of N2-, O2-, and air-clathrates by neutron diffraction

A laboratory investigation into the seismic velocities of methane gas hydrate‐bearing sand

Advances in Study of Mechanical Properties of Gas Hydrate-Bearing Sediments

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