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Topic: Hydrate


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In the News (Fri 1 Aug 14)

  
  Hydrate - Wikipedia, the free encyclopedia
Hydrates are compounds formed by the union of water with some other substance, generally forming a neutral body, as certain crystallized salts.
Hence, hydrates are derivatives of, or compounds with, hydroxyl.
gas hydrates are clathrate hydrates: water ice with gas molecules trapped within.
en.wikipedia.org /wiki/Hydrate   (223 words)

  
 Gas hydrate - Wikipedia, the free encyclopedia
Clathrate hydrates are a class of solids in which gas molecules occupy "cages" made up of hydrogen-bonded water molecules.
Hydrates consist of a water lattice in which light hydrocarbon molecules are embedded resembling dirty ice.
Hydrates normally form when a gas stream is cooled below its hydrate formation temperature in the presence of free water i.e.
en.wikipedia.org /wiki/Gas_hydrate   (894 words)

  
 USGS Fact sheet: Gas (Methane) Hydrates -- A New Frontier   (Site not responding. Last check: 2007-11-07)
Methane trapped in marine sediments as a hydrate represents such an immense carbon reservoir that it must be considered a dominant factor in estimating unconventional energy resources; the role of methane as a 'greenhouse' gas also must be carefully assessed.
Hydrates store immense amounts of methane, with major implications for energy resources and climate, but the natural controls on hydrates and their impacts on the environment are very poorly understood.
Methane hydrate is stable in ocean floor sediments at water depths greater than 300 meters, and where it occurs, it is known to cement loose sediments in a surface layer several hundred meters thick.
marine.usgs.gov /fact-sheets/gas-hydrates/title.html   (989 words)

  
 Gas Hydrate at the USGS, What is it?
Hydrate forms as cement in the pore spaces of sediment as well as in layers and nodules of pure hydrate.
Hydrate is a gas concentrator; the breakdown of a unit volume of methane hydrate at a pressure of one atmosphere produces about 160 unit volumes of gas.
Gas hydrate concentration occurs at depocenters, probably because most gas in hydrate is from biogenic methane, and therefore it is concentrated where there is a rapid accumulation of organic detritus (from which bacteria generate methane) and also where there is a rapid accumulation of sediments (which protect detritus from oxidation).
woodshole.er.usgs.gov /project-pages/hydrates/what.html   (430 words)

  
 DEA Briefs & Background, Drugs and Drug Abuse, Drug Descriptions, Chloral Hydrate
A solution of chloral hydrate and alcohol constituted the infamous "knockout drops" or "Mickey Finn." At therapeutic doses, chloral hydrate has little effect on respiration and blood pressure; however; a toxic dose produces severe respiratory depression and very low blood pressure.
Although some physicians consider chloral hydrate to be the drug of choice for sedation of children before diagnostic, dental, or medical procedures, its general use as a hypnotic has declined.
Chloral hydrate (Noctec® and other) and compounds, preparations, or mixtures containing choral hydrate are in Schedule IV of the CSA.
www.usdoj.gov /dea/concern/chloral_hydrate.html   (156 words)

  
 METHANE HYDRATE AND BSRS
A methane hydrate is an ice-like, crystalline lattice of water molecules in which gas molecules are trapped physically without the aid of direct chemical bonds.
As the zone of methane hydrate thickens and deepens, its base eventually subsides into a temperature region where the hydrate is unstable.
In this case the BSR is the consequence of the impedance contrast between overlying sediments containing substantial amounts of high-velocity hydrate and underlying normal velocity brine sediments.
sepwww.stanford.edu /public/docs/sep79/christin/paper_html/node2.html   (418 words)

  
 GAS HYDRATE HOME PAGE OF Dr.VLADIMIR YAKUSHEV
Formation of Methane hydrates takes place in the Earth crust when there are favorable thermodynamic conditions (area including 95% of ocean floor square from water depth 300-600 m and approximately 50% of permafrost square from permafrost thickness 280 m) and favorable lithologic and geochemical conditions.
For remote detection of hydrate-containing sediments further development of seismic survey is needed for marine hydrates and combination of seismic and electric resistivity profiling for underpermafrost hydrates on land.
Practically all aspects of gas hydrate study are involved into their field of interest, but main studies are carrying on thermodynamic equilibria, experimental equipment design and manufacturing, hydrate-containing sediments experimental study and industrial applications of gas hydrates.
www.geocities.com /ResearchTriangle/Node/1622   (2126 words)

  
 Hydrate dissociation in pipelines   (Site not responding. Last check: 2007-11-07)
The temperature of the hydrate during dissociation was assumed to be constant throughout the plug and in equilibrium with the prevailing pressure.
The dissociation of the hydrate plug was initated by decreasing the pressure at both ends of the plug.
As the hydrate was dissociating, two things could be measured; the amount of methane gas released from the dissociating hydrate (using a water displacement device), and the temperature of the hydrate at the center of the plug at five different axial positions.
www.mines.edu /research/chs/David.html   (2424 words)

  
 Formula of a Hydrate   (Site not responding. Last check: 2007-11-07)
Hydrates are inorganic salts which contain a specific number of water molecules loosly attached.
When determining theformula of a hydrate you must not assume that it is one with a simple formula.
Hydrates can normally be decomposed into the anhydrous salt and water by gentle heating.
chem.lapeer.org /chem1docs/HydrateLab1.html   (537 words)

  
 High Pressure Hydrate measurements   (Site not responding. Last check: 2007-11-07)
A hydrate optical cell was designed and fabricated for the measurements of high-pressure hydrate phase equilibria.
Such conditioning was necessary to form a uniform hydrate sample, one with a relative cavity occupancy ratio around 3 to 1 (large cavity to small cavity ratio for sI hydrate).
Hydrate dissociation was indicated by a jump in pressure at around 3200 seconds, and this event coincided with changes in the Raman spectroscopic data.
www.mines.edu /research/chs/Vu.html   (1787 words)

  
 Oceanic Hydrates an elusive resource
Methane hydrate is different because methane is held inside the lattice of the molecular structure of water in the proportion of 1/ 5.75.
It is important to recognize that the methane in hydrates is held in the molecular structure as a solid as soon it is generated in the zone of hydrate stability.
It is hard to believe that hydrates contained in the first 600 m of oceanic sediments covering a period of less than 10 millions years could hold twice more carbon than the fossil fuels from 6000 m of sediments covering a period of more than 500 millions years.
dieoff.com /page192.htm   (6399 words)

  
 GAS HYDRATE   (Site not responding. Last check: 2007-11-07)
Collectively, physical and chemical data suggest that small quantities of gas hydrate are present, at least intermittently, from ~70 mbsf to the base of the recovered interval at 278.3 mbsf.
The dissociation of gas hydrate is an endothermic reaction that produces gas and decreases the temperature of surrounding sediment (Sloan, 1990).
It is consistent with the presence of several percent gas hydrate in pore space of sediment at ~150 mbsf.
www.ga.gov.au /odp/publications/201_IR/chap_11/c11_10.htm   (1886 words)

  
 Chloral Hydrate   (Site not responding. Last check: 2007-11-07)
First synthesized in 1832, chloral hydrate was the first depressant developed for the specific purpose of inducing sleep.
Today depressants such as chloral hydrate are packaged with labels warning against the danger of mixing these kinds of sedatives with alcohol or other depressants.
Despite the abuse and mis-administration of the sedative, chloral hydrate did fulfill a need for a drug that would ease sleeplessness due to pain or insomnia and is considered a positive medical discovery.
drugs.uta.edu /chloral.html   (368 words)

  
 Seismic Characterization Of Methane Hydrate Structures
I infer the cause of the BSR visible in the data and estimate the amount of hydrate present in the sediment structure.
I examine three micromechanical models of hydrate formation: (A) hydrate is part of the pore fluid, (B) hydrate becomes part of the solid frame, and (C) hydrate cements grain contacts together.
Model A predicts maximum hydrate saturation between 20% and 26%, model B saturations between 15% and 20%, and model C saturations of less than 1%.
sepwww.stanford.edu /public/docs/sep96/paper_html   (345 words)

  
 Chloral Hydrate
Chloral Hydrate acts as a depressant on the central nervous system, it has sedative effects similar to those of barbiturates and benzodiazepines.
Chloral Hydrate is also known as Trichloroacetaldehyde Monohydrate, and is used medically as a sleeping pill.
Although chloral hydrate is still used medically today, typically in the elderly or young, its use declined with the introduction of the barbiturates.
www.a1b2c3.com /drugs/chl02.htm   (542 words)

  
 Global Inventory of Natural Gas Hydrate Occurance - USGS WR CMG
Natural gas hydrate occurs worldwide in oceanic sediment of continental and insular slopes and rises of active and passive margins, in deep-water sediment of inland lakes and seas, and in polar sediment on both continents and continental shelves.
Thus, natural gas hydrate is restricted to the shallow geosphere where its presence affects the physical and chemical properties of near-surface sediment.
This updated global inventory reports on natural gas hydrate recovered from 20 places worldwide and includes 79 places where the presence of gas hydrate has been inferred from geophysical, geochemical, or geological evidence.
walrus.wr.usgs.gov /globalhydrate   (219 words)

  
 Gas Hydrate at the USGS, Title Page
Gas Hydrate is an ice-like crystalline solid formed from a mixture of water and natural gas, usually methane.
Gas Hydrate is found in sub-oceanic sediments in the polar regions (shallow water) and in continental slope sediments (deep water), where pressure and temperature conditions combine to make it stable.
Gas Hydrate can be studied in the laboratory, where a machine is used to create the proper pressure and temperature conditions for hydrate formation, or it can be studied in situ using seismic data collected aboard ships and geophysical models.
woodshole.er.usgs.gov /project-pages/hydrates   (234 words)

  
 USGS OF 96-272, Offshore Gas Hydrate Sample Database, Overview and Preliminary Analysis, 2. Introduction
Toward understanding the processes that lead to highly concentrated or massive deposits of marine gas hydrates, a database of offshore gas hydrate samples was constructed from published observations and measurements (Appendix).
Finally, a hydrate may be moved horizontally or vertically relatively great distances from its original position and/or its original methane source in response to tectonic forces or other geologic process.
Methane hydrate is used for illustration because it is by far the most abundant hydrate found in marine sediments.
pubs.usgs.gov /of/1996/of96-272/ch02.html   (634 words)

  
 Hydrate --  Britannica Student Encyclopedia   (Site not responding. Last check: 2007-11-07)
O molecules; best known hydrates are crystalline solids that lose their fundamental structures upon removal of the bound water; examples of hydrates are: Glauber's salt (sodium sulfate decahydrate, Na O); washing soda (sodium carbonate decahydrate, Na O); borax (sodium tetraborate decahydrate, Na O); and blue vitriol…
The best known hydrates are crystalline solids that lose their fundamental structures upon removal of the bound water.
Portland cement is a powder that hydrates (combines chemically with water), to form a paste that binds sand, gravel, and stone into a rocklike mass called...
www.britannica.com /ebi/article-9326930?tocId=9326930   (797 words)

  
 MedlinePlus Drug Information: Chloral Hydrate (Systemic)   (Site not responding. Last check: 2007-11-07)
Chloral hydrate has been used in the treatment of insomnia (trouble in sleeping) and to help calm or relax patients who are nervous or tense.
Although there is no specific information comparing use of chloral hydrate in the elderly with use in other age groups, this medicine is not expected to cause different side effects or problems in older people than it does in younger adults.
Overdose of chloral hydrate is especially dangerous in children.
www.nlm.nih.gov /medlineplus/druginfo/uspdi/202123.html   (1879 words)

  
 Nat' Academies Press, Charting the Future of Methane Hydrate Research in the United States (2004)
The original program solicitation issued in 2001 was targeted and included studies addressing gas hydrate research needs in four specific research areas: (1) the Gulf of Mexico (both lab and field), (2) Alaska, (3) hydrate as a medium for transporting natural gas, and (4) gas hydrate modeling consortium and partnership development.
The data gathered on Leg 204 greatly improved knowledge of the distribution of gas hydrate on continental margins and the dynamics of gas hydrate formation and dissociation in the marine environment.
Charting the Future of Methane Hydrate Research in the United States The USGS has a long history of gas hydrate research (in both the laboratory and the field) and collaboration, which has provided basic and essential information on the chemistry of gas hydrate.
www.nap.edu /books/0309092922/html/43.html   (6045 words)

  
 CD Baby: HYDRATE: hydrate
hydrate spans the rock and metal worlds: some dark, some upbeat, some heavy, some melodic, and some plain-strange.
rooted in various influences ranging from tool to incubus, from the used to disturbed, from foo fighters to system of a down, hydrate's evolution has tapped a wide variety of styles and genres to bring you the unique sound evident on the self-titled debut album.
with the self-titled debut album complete, hydrate shifted focus to live performances, new song writing, and bringing it all to the fans.
www.cdbaby.com /hydrate   (292 words)

  
 Hydrate Ridge Offset-VSPs
The study of gas hydrates and free gas in an accretionary wedge with high fluid-flux and strong small-scale lateral variability is the focus of planned ODP Leg 204 on Hydrate Ridge, offshore Oregon (fig.
Recent laboratory and borehole studies confirm that gas hydrates lead to a significant increase of shear wave velocity (Vs), which emphasizes that Vs is a critical parameter for gas hydrate characterization.
Together with drilling, these experiments are designed to constrain relationships between hydrate formation and gas sources and to characterize and analyze the development of a gas hydrate reservoir in the high fluid-flux environment of a convergent margin.
www.ig.utexas.edu /research/projects/hydrate_ridge/hydridge.htm   (690 words)

  
 Alaska Well Targets Gas Hydrate, Produces Wealth of Information
Methane hydrate is a compound of water and methane (the major component of natural gas) that forms under pressure at cold temperatures.
This is critical to the accurate characterization of hydrate in cores because methane hydrate quickly separates into methane gas and water when warmed.
In this first attempt at continuously coring permafrost to detect methane hydrate, the well was cored from a depth of 82 feet to 2,300 feet, with 93 percent of the core successfully recovered.
www.netl.doe.gov /publications/press/2004/tl_anadarko3.html   (1115 words)

  
 hydrate   (Site not responding. Last check: 2007-11-07)
The empirical formula of a compound is defined as the "simplest whole number ratio of the atoms" in the compound [Drago, S.: Principles of Chemistry with Practical Perspectives.
The same approach is useful for the determination of the number of moles of water of hydration (crystallization) in various salts:
Obtain a striker, crucible tongs, petri "boats", two crucibles and covers, a ring stand, a Bunsen burner and tubing, a ring with clay triangle and an unknown hydrate of copper (II) sulfate.
tooldoc.wncc.nevada.edu /hydrate.htm   (551 words)

  
 O.I. Levik Hydrate Site   (Site not responding. Last check: 2007-11-07)
Clarke, M.A.: Determination of the Intrinsic Kinetics of Gas Hydrate Decomposition by Particle-Size Analysis, University of Calgary, 2000.
Dharmawardhana, P.B.: The Measurement of the Thermodynamic Parameters of the Hydrate Structure and the Application of them in the Prediction of the Properties of Natural Gas Hydrates, Colorado School of Mines, 1980.
Gudmundsson's hydrate group at the Norwegian University of Science and Technology works with hydrates as a media for transport of natural gas.
www.levik.no /hydrates.html   (1636 words)

  
 Hydrate
Hydrates are crystalline solid compounds formed from water and smaller molecules.
In combination with water, many of the components commonly found in natural gas form hydrates.
In the natural gas business hydrates are highly problematic.
members.shaw.ca /hydrate   (75 words)

  
 MedlinePlus Drug Information: Chloral Hydrate
Chloral hydrate, a sedative, is used in the short-term treatment of insomnia (to help you fall asleep and stay asleep for a proper rest) and to relieve anxiety and induce sleep before surgery.
Chloral hydrate comes as a capsule and liquid to take by mouth and as a suppository to insert rectally.
Chloral hydrate can be habit-forming; do not take a larger dose, take it more often, or for a longer period than your doctor tells you to.
www.nlm.nih.gov /medlineplus/druginfo/medmaster/a682201.html   (770 words)

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