Hydrogen Molecules in the Small Dodecahedral Cage of a Clathrate Hydrate:  Quantum Translation−Rotation Dynamics of the Confined Molecules

2007 ◽  
Vol 111 (6) ◽  
pp. 2497-2504 ◽  
Author(s):  
Francesco Sebastianelli ◽  
Minzhong Xu ◽  
Yael S. Elmatad ◽  
Jules W. Moskowitz ◽  
Zlatko Bačić
Keyword(s):  
Clathrate Hydrate ◽  
Hydrogen Molecules ◽  
Rotation Dynamics

Dynamics of hydrogen molecules in the channels of binary THF-H2 clathrate hydrate and its physicochemical significance on hydrogen storage

2010 ◽  
Vol 35 (23) ◽  
pp. 13068-13072 ◽  
Author(s):  
Yong Nam Choi ◽  
J.M. Sungil Park ◽  
Thierry Strässle ◽  
Sun-Hwa Yeon ◽  
Youngjune Park ◽  
...  
Keyword(s):  
Hydrogen Storage ◽  
Clathrate Hydrate ◽  
Hydrogen Molecules

THERMODYNAMICS AND HYDROGEN STORAGE ABILITY OF BINARY HYDROGEN + HELP GAS CLATHRATE HYDRATE

2009 ◽  
Vol 08 (01n02) ◽  
pp. 57-63 ◽  
Author(s):  
V. R. BELOSLUDOV ◽  
O. S. SUBBOTIN ◽  
R. V. BELOSLUDOV ◽  
H. MIZUSEKI ◽  
Y. KAWAZOE ◽  
...  
Keyword(s):  
Gas Phase ◽  
High Pressures ◽  
Hydrate Formation ◽  
Zero Point ◽  
Hexagonal Structure ◽  
Clathrate Hydrate ◽  
Intermolecular Potential ◽  
Pure Hydrogen ◽  
Promising Alternative ◽  
Hydrogen Molecules

Storage of hydrogen as hydrogen hydrate is a promising alternative technology to liquefied hydrogen at cryogenic temperatures or compressed hydrogen at high pressures. In this paper, computer simulation is performed based on the solid solution theory of clathrates of van der Waals and Platteeuw with some modifications that include in particular the account of multiple cage occupancies and host relaxation. The quasiharmonic lattice dynamics method employed here gives the free energy of clathrate hydrate to first order in the anharmonicity of intermolecular potential and permits to take into account quantum zero-point vibration of host lattice and hydrogen in the cages. It is employed to study the thermodynamic functions of binary (mixed) H 2– CH 4 hydrates of cubic structure II (sII) and hexagonal structure H (sH). It is shown that at divariant equilibrium "gas phase–gas hydrate" with increasing pressure the filling of large cavities by hydrogen proceeds gradually from single filling to the maximal number of hydrogen molecules in clusters included in large cages (four in sII and five in sH) preserving stability of the hydrogen–methane hydrates sII and sH. The results show that mass fraction of hydrogen in the mixed sH hydrate is significantly lower than in the mixed sII hydrate. Pressure of monovariant equilibrium " IceI h–gas phase–mixed sII hydrate" with increasing methane concentration in the gas phase lowers in comparison with the pressure of pure hydrogen hydrate formation. For the mixed hydrogen + methane sH hydrates, it was demonstrated that thermodynamic stability depends on the filling degree of small cavities by methane molecules and stability area shifts to lower pressure with increasing filling.

scholarly journals Thermodynamic Properties of Hydrogen + Tetra-n-Butyl Ammonium Bromide Semi-Clathrate Hydrate

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
Shunsuke Hashimoto ◽  
Takaaki Tsuda ◽  
Kyohei Ogata ◽  
Takeshi Sugahara ◽  
Yoshiro Inoue ◽  
...  
Keyword(s):  
Phase Equilibrium ◽  
Clathrate Hydrate ◽  
Ammonium Bromide ◽  
Mixed Gas ◽  
Raman Spectroscopic ◽  
Hydrogen Molecules ◽  
Three Phase ◽  
Hydrogen Fugacity ◽  
Pressure Swing ◽  
Phase Equilibrium Condition

Thermodynamic stability and hydrogen occupancy on the hydrogen + tetra-n-butyl ammonium bromide semi-clathrate hydrate were investigated by means of Raman spectroscopic and phase equilibrium measurements under the three-phase equilibrium condition. The structure of mixed gas hydrates changes from tetragonal to another structure around 95 MPa and 292 K depending on surrounding hydrogen fugacity. The occupied amount of hydrogen in the semi-clathrate hydrate increases significantly associated with the structural transition. Tetra-n-butyl ammonium bromide semi-clathrate hydrates can absorb hydrogen molecules by a pressure-swing without destroying the hydrogen bonds of hydrate cages at 15 MPa or over.

Quantum and classical inter-cage hopping of hydrogen molecules in clathrate hydrate: temperature and cage-occupation effects

2017 ◽  
Vol 19 (1) ◽  
pp. 717-728 ◽  
Author(s):  
Christian J. Burnham ◽  
Zdenek Futera ◽  
Niall J. English
Keyword(s):  
Free Energy ◽  
Quantum Effects ◽  
Clathrate Hydrate ◽  
Energy Barriers ◽  
Hydrogen Molecules ◽  
Nuclear Quantum Effects

The free-energy barriers for hydrogen hopping between clathrate-hydrate cavities were evaluated at 50–200 K. Nuclear quantum effects are significant.

How many hydrogen molecules (H2) can be stored in a clathrate hydrate cage?

2018 ◽  
Vol 10 (3) ◽  
pp. 034902 ◽  
Author(s):  
Dapeng Li ◽  
Shuqing Wang ◽  
Qishi Du ◽  
Ribo Huang
Keyword(s):  
Clathrate Hydrate ◽  
Hydrogen Molecules

Structure and Dynamics of Hydrogen Molecules in the Novel Clathrate Hydrate by High Pressure Neutron Diffraction

2004 ◽  
Vol 93 (12) ◽  
Author(s):  
Konstantin A. Lokshin ◽  
Yusheng Zhao ◽  
Duanwei He ◽  
Wendy L. Mao ◽  
Ho-Kwang Mao ◽  
...  
Keyword(s):  
High Pressure ◽  
Neutron Diffraction ◽  
Clathrate Hydrate ◽  
The Novel ◽  
Structure And Dynamics ◽  
Hydrogen Molecules

Effects of Cooking Processes on Breath Hydrogen and Colonic Fermentation of Soybean

2020 ◽  
Vol 16 (4) ◽  
pp. 488-493
Author(s):  
Naoya Okumura ◽  
Naoya Jinno ◽  
Kentaro Taniguchi ◽  
Kenichi Tanabe ◽  
Sadako Nakamura ◽  
...  
Keyword(s):  
Healthy Adult ◽  
Area Under The Curve ◽  
Cooking Methods ◽  
Breath Hydrogen ◽  
Gas Chromatograph ◽  
Colonic Fermentation ◽  
Hydrogen Molecules ◽  
Nutritional Analysis ◽  
Hydrogen Level ◽  
Adult Volunteers

Background: Soybean is rich in dietary fibers; consequently, soybean ingestion considerably increases the breath level of hydrogen molecules via anaerobic colonic fermentation. However, the influence of cooking methods on this effect, which can affect the overall health benefits of soybean, remains unknown. Objectives: The aim is to examine whether different methods of cooking soybean affect the colonic fermentation process. Methods: Nine healthy adult volunteers participated in the study; they ingested either roasted soybean flour (kinako) or well-boiled soybean (BS). Differences in their breath components were compared. Both test meals were cooked using 80 g of soybeans per individual. After a 12 h fast, the participants ate the test meals, and their breath hydrogen level was analyzed every 1 h for 9 h by using a gas chromatograph with a semiconductor detector. In addition, particle size distribution and soluble/ insoluble fibers in the feces were examined. Results: The oro-cecal transit time did not significantly differ between individuals who ingested kinako and BS. However, the area under the curve between 7 and 9 h after the ingestion of BS was significantly increased compared with that after the ingestion of kinako. The nutritional analysis indicated that the content of both soluble and insoluble fibers in BS was higher than that in kinako. In addition, the levels of unfermented fragments and soluble/insoluble fibers in the feces were increased after the ingestion of kinako compared with those after the ingestion of kinako. Conclusion: Cooking methods alter the composition of non-digestible fibers in soybean, and this can result in the lack of fermentative particles in the feces, thereby causing alterations in the breath level of hydrogen via colonic fermentation.

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