Vast quantities of natural gas are held in hydrate form in geologic reservoirs in sub-oceanic sediments and arctic permafrost zones (KVENVOLDEN, 1988; SLOAN, 1998), where conditions of high pressure and low temperature are within the hydrate stability region. In 1995, the U.S. Geological Survey (USGS) conducted a study to assess the quantity of natural gas hydrate resources in the United States...

Molecular dynamics simulations were performed for CO2 dissolved in water near silica surfaces to investigate how the hydrophilicity and crystallinity of solid surfaces modulate the local structure of adjacent molecules and the nucleation of CO2 hydrates. Our simulations reveal that the hydrophilicity of solid surfaces can change the local structure of water molecules and gas distribution near l...

Simulation of the system behavior of hydrate-bearing geologic media involves solving fully coupled massand heat-balance equations. In this study, we develop a domain decomposition approach for large-scale gas hydrate simulations with coarse-granularity parallel computation. This approach partitions a simulation domain into small subdomains. The full model domain, consisting of discrete subdomai...

This work has developed techniques for studying the mechanism by which a hydrate growth inhibitor, i.e. poly(vinylpyrro1idone) (PVP), acts. The topology of a series of (111) faces of the type I1 clathrate hydrate, the postulated growth plane, have been studied in detail and used to calculate hydrogen-bond energy surfaces. N-Ethylpyrrolidone (NEP), the monomeric unit, has been used to sample ads...

UNLABELLED PREMISE OF THE STUDY This study presents Visikol™, a new proprietary formulation that can be used as an efficient replacement for chloral hydrate as a clearing agent for microscopic examination. In the United States, chloral hydrate is regulated and therefore difficult to acquire. • METHODS AND RESULTS Fresh and dry samples of the following plants: ginger (Zingiber officinale), ...

This paper presents strategies for producing negatively buoyant CO2 hydrate composite particles for ocean carbon sequestration. Our study is based on recent field observations showing that a continuous-jet hydrate reactor located at an ocean depth of ~1500 m produced curved negatively buoyant cylindrical particles with diameters ~ 2.5 cm and lengths up to ~ 1 m. Accordingly we performed new lab...

Cork industries generate a considerable amount of solid waste during their processing. Its management implies a problem for companies that should reconsider its reuse for other purposes. In this work, an analysis of pelletizing of granulometric separation powder, which is one of the major wastes in cork industries and which presents suitable properties (as an raw material) for its thermal use, ...

Vast quantities of methane are trapped in oceanic hydrate deposits, and there is concern that a rise in the ocean temperature will induce dissociation of these hydrate accumulations, potentially releasing large amounts of methane into the atmosphere. The recent discovery of active methane gas venting along the landward limit of the gas hydrate stability zone (GHSZ) on the shallow continental sl...

The observed moisture- and temperature dependent transformations of the dapsone (4,4'-diaminodiphenyl sulfone, DDS) 0. 33-hydrate were correlated to its structure and the number and strength of the water-DDS intermolecular interactions. A combination of characterization techniques was used, including thermal analysis (hot-stage microscopy, differential scanning calorimetry and thermogravimetric...

Conceptually new methods of hydrate formation are proposed. The first one is based on the shock wave impact on a water-bubble medium. It is shown that the hydrate formation rate in this process is typically very high. A gas hydrate of carbon dioxide was produced. The process was experimentally studied using various initial conditions, as well as different external action magnitudes. The obtaine...