
	Where results make sense

Topic: High density amorphous ice

Related Topics

Ice

Ice XII

In the News (Fri 18 Dec 09)

Northern Trust

Marvin Harrison

Peter Chernin

Gary Locke

Match Play

Penelope Cruz

Mickey Rourke

AR Rahman

Danny Boyle

Hugh Jackman

	SNOW HYDROLOGY (GEOG 4321): ICE PHYSICS
		Ice has a rigid lattice structure because in ice each each molecule is hydrogen bonded to 4 other molecules.
		In ice, a water molecule has four nearest neighbors to which it is bonded via hydrogen bonds (two from its hydrogen atoms and two from the lone electron pairs on the oxygen).
		Therefore the density of ice Ih is 917 kg/m3, compared with a density of 1,000 kg/m3 for liquid water at 4 degC.
	snobear.colorado.edu /Markw/SnowHydro/mol.html (1962 words)

	Ice - Food & Drink - Recipes24 Net - recipes, cooking, cookbooks and more
		Ice is a common metaphor for things that are cold, hard, and clear in some way; for instance, "ice" is a colloquial term for diamond, and also for some forms of the drug amphetamine.
		When ice melts, it absorbs as much heat energy (the heat of fusion) as it would take to heat an equivalent mass of water by 80 °C, while its temperature remains a constant 0 °C. Consequently, ice has long been valued as a means of cooling.
		Ice scrapers are tools designed to break the ice free and clear the windows, though removing the ice can be a long, labor-intensive, and stressful process?especially when a driver ends up running late for work as a result.
	www.recipes24.net /encyclopedia/i/ice.html (1305 words)

	Amorphous ice - Wikipedia, the free encyclopedia
		Amorphous ice is an amorphous solid form of water, meaning it consists of water molecules that are randomly oriented like the atoms of common glass.
		Amorphous ice is produced by cooling liquid water very quickly (around 1,000,000 K/s), so the molecules don't have enough time to form a crystal lattice.
		Amorphous ice is used in some scientific experiments, especially in electron cryomicroscopy of biomolecules.
	en.wikipedia.org /wiki/Amorphous_ice (758 words)

	Ice
		Ice can be formed at higher temperatures in pressurized environments, and water will remain a liquid or gas until -30°C at lower pressures.
		Ice, water and water vapour can coexist at the triple point, which for this system is 273.16K at a pressure of 611.73 Pa.
		An unusual feature of ice frozen at a pressure of one atmosphere is that the solid is less dense than liquid water (10% less).
	www.ebroadcast.com.au /lookup/encyclopedia/ic/Ice.html (431 words)

	High-density amorphous ice, the frost on interstellar grains. (Site not responding. Last check: 2007-10-26)
		Most water ice in the Universe is in a form which does not occur naturally on Earth and of which only minimal amounts have been made in the laboratory.
		Several features of astrophysical ice analogs studied in laboratory experiments are readily explained by the structural transition from high-density amorphous ice into low-density amorphous ice.
		While the 3.07 mu m ice band in various astronomical environments can be modeled with spectra of simple mixtures of amorphous and crystalline forms, the contribution of the high-density amorphous form nearly always dominates.
	exobiology.nasa.gov /ssx/biomod/papers990823/ice.s11/ice.s11.html (279 words)

	Ice - Biocrawler (Site not responding. Last check: 2007-10-26)
		An ancient ice house, called a yakhchal, built in Kerman, Iran, during the middle ages, for storing ice during summers.
		Ice also plays a role in winter recreation, namely the sports of ice skating, ice hockey, ice fishing, ice climbing and bobsledding and luge sled racing.
		Whenever there is freezing rain or snow that occurs at a temperature near the melting point, it is common for ice to build up on the windows of vehicles, safely driving of which reauires removal of the ice.
	www.biocrawler.com /encyclopedia/Ice (1470 words)

	Ice (Site not responding. Last check: 2007-10-26)
		When ice melts, it absorbs as much heat energy (the heat of fusion) as it would take to heat an equivalent mass of water by 80 В°C, while its temperature remains a constant 0 В°C. As a crystalline solid, ice is considered a mineral.
		Ice also plays a role in winter recreation, in sports such as ice skating, ice hockey, ice fishing, ice climbing and sled racing on bobsled and luge.
		Ice is also a slang word for things that are cold, hard, and clear in some way, such as diamonds and some forms of the drug amphetamine.
	www.paleorama.com /Disney-I/Ice.php (1690 words)

	ICE
		Ice II is a completely proton-ordered phase for which the proton-disordered version is unstable and is not observed.
		Ice Ic is related to ice Ih in the same way as cubic diamond is related to hexagonal diamond, the cubic and hexagonal forms having almost the same density.
		The reorientation of the molecular dipoles in ice is facilitated by the mobility of orientational L and D defects, which are generated by thermal activation.
	skua.gps.caltech.edu /hermann/ice.htm (1983 words)

	The Analytic-Synthetic Dichotomy - Objectivist Living Forum
		Ice is simply an example, and he's talking about normal ice, not very high density ice.
		With definition "ice is the solid form of water", the statement "ice does not sink in water" is incorrect, it is true for some forms of ice, but not for all forms of ice.
		The statement "ice floats on water" is a typical synthetical truth: we were not aware that there exists also ice that sinks in water, it is an example of the fact that all our empirical knowledge is tentative.
	www.objectivistliving.com /forums/index.php?showtopic=241 (7472 words)

	* News @Guelph *
		Because amorphous ices don't form crystals, they have the potential to be used to preserve fragile organisms.
		The researchers came across this discovery when they were doing lengthy experiments with the high-density form of amorphous ice, which is made by putting ice into a metal press and squeezing it at 13,000 times atmospheric pressure, then cooling it to -196 C using liquid nitrogen.
		The high-density amorphous ice samples used in the study came from the National Research Council in Ottawa and were then shipped to the Advanced Photon Source at Argonne National Lab in Illinois, where the experiments were carried out using high-energy X-ray and neutron scattering.
	www.uoguelph.ca /atguelph/02-09-25/articles/ice.html (598 words)

	Re: ice
		Ice VII for instance is so dense that it actually consists of two interpenetrating networks of ice.
		Ice X (stable above 100 GPa) is so dense that the concept of hydrogen bond acceptor and donor breaks down - the proton sits exactly in the middle between two oxygens.
		All the high density forms of ice behave like popcorn when bringing them to room temperature (since they transform to the lower density stable forms) and are referred to non-scientifically as "popcorn ices".
	www.lns.cornell.edu /spr/2003-01/msg0047785.html (300 words)

	OSB: Ice dream (Site not responding. Last check: 2007-10-26)
		Ice, water, and water vapor can coexist at the triple point, which for this system is 273.16 K at a pressure of 611.73 Pascal.
		Ice is a common metaphor for things that are cold, hard, and clear in some way; for instance, "ice" is a colloquial term for diamond, and also for some forms of the drug amfetamine.
		It is troublesome to remove this form of ice, so people often open their windows slightly when the vehicle is parked in order to let the moisture dissipate, and it is now common for cars to have s to combat the problem.
	www.onesimpleband.com /ice-cream-makers/ice-dream.html (1612 words)

	Water phase diagram including high density ices
		The chemical properties of water are also greatly changed at high temperatures and pressures due to the changes in ionization, solubility, diffusivity and reactivity due to decreasing hydrogen-bonding [1116].
		Cubic ice (Ic) is metastable with respect to hexagonal ice (Ih).
		Ice Ih may be metastable with respect to empty clathrate structures of lower density under negative pressure conditions (that is, stretched) at very low temperatures [520].
	www.lsbu.ac.uk /water/phase.html (1385 words)

	Explanation of the Phase Anomalies of Water (P1-P12)
		Hexagonal ice shows anomalous reduction in thermal conductivity with increasing pressure (as do cubic ice and low-density amorphous ice but not high-density amorphous ice), which behavior is different from most crystals where thermal conductivity increases with increasing density.
		In a similar manner to the formation of the high density crystalline (ice-five and ice seven) and amorphous (HDA) ice phases, it is likely that liquid water undergoes a significant change in structure at high pressure (about 200 MPa for liquid water).
		This structuring for liquid water at high pressures is consistent to that found by neutron scattering [1001] and indicates that liquid water structuring at high pressure has similarity to that of its high pressure ice phases [1254].
	www.lsbu.ac.uk /water/explan.html (2672 words)

	Amorphous ice and glassy water
		These amorphous ices are not required to obey the 'ice rules' and may contain a significant number of dangling bonds.
		There is a recent comprehensive review of the amorphous phases of ice and their transitions [569] and an interesting simulation study of this polymorphism [590].
		An interesting property of HDA is that the thermal conductivity decreases from that of ice Ih, ice Ic or LDA during their pressurized densification, as usually the thermal conductivity of materials increases with increasing pressure [618b].
	lsbu.ac.uk /water/amorph.html (2006 words)

	Work on ice at NASA/Ames Research Center's Space Science Microscopy Lab (Site not responding. Last check: 2007-10-26)
		A numerical model of High Density Amorphous ice made by quenching configurations of liquid water, shows that this form of ice lacks the large cavities.
		High density amorphous ice is the most abundant ice in the universe, where it is found as a frost on interstellar grains.
		This ice is the craddle where small inorganic molecules combine into large organic molecules that may be at the origin of life.
	exobiology.nasa.gov /ice/high.html (417 words)

	Ice-seven and ice ten-structures
		Ice VII consists of two interpenetrating cubic ice lattices with hydrogen bonds passing through the center of the water hexamers and no connecting hydrogen-bonds between lattices.
		The hydrogen bonding is disordered and constantly changing as in hexagonal ice but ice-seven undergoes a proton disorder-order transition to ice-eight at about 5°C; ice-seven and ice-eight having identical structures apart from the proton ordering.
		The oxygen atoms are arranged in a body-centered cubic arrangement (8 neighbors) and the hydrogen atoms in a body-centered truncated cubic arrangement (12 neighbors).
	www.lsbu.ac.uk /water/ice_vii.html (473 words)

	Science News
		Known to make up the bulk of water in comets and to coat interstellar dust grains, amorphous ice may be the most abundant type of water in the universe.
		After the 1992 simulations of supercooled liquid water, some scientists speculated that amorphous ice and supercooled water are essentially the same substance, and environmental conditions, such as temperature and pressure, determine whether the material is a solid or a liquid.
		Mishima and Stanley found the expected shift in ice IV's melting conditions, but they were unable to verify that it was as sharp as predicted by the theory.
	www.phschool.com /science/science_news/articles/wet_n_wild.html (2316 words)

	High Pressure Physics and the Centre for Science at Extreme Conditions (CSEC)
		The discovery that liquid-liquid phase transitions are relatively common at high pressure has sparked growing interest in the structures of high-density liquids and how they relate to the crystalline state.
		Studies of the interplay between van der Waals forces and stearic repulsions as the density increase are relevant to the goal of describing weak forces and provide information needed for classical molecular dynamics modelling.
		The behaviour of systems such as ices, methane clathrate and ammonia hydrates are crucial for modeling of planets such as Uranus and Neptune (Figure 3).
	www.ph.ed.ac.uk /cmatter/highpressure.html (1659 words)

	Campus News: U of G physicists discover new form of ice
		Amorphous ices don’t form on Earth naturally because they only exist below —150 C, making this research of interest to astro-physicists since the ice can form in outer space.
		The researchers came across this discovery when they were doing lengthy experiments with the high density form of amorphous ice, which is made by putting ice into a metal press and squeezing it at 13,000 times atmospheric pressure and then cooling it to —196 C using liquid nitrogen.
		The high density amorphous ice samples used in the study came from the National Research Council in Ottawa and were then shipped to the Advanced Photon Source at Argonne National Lab in Illinois where the experiments were carried out using high energy x-ray and neutron scattering.
	www.uoguelph.ca /mediarel/archives/001772.html (632 words)

	materials science 01
		Ice XII is produced at about 0.55 GPa and 260 K. It provides the first example of a four-connected network which is built up by seven- and eight-membered rings
		Ice XII, therefore, is rather prolific in water's phase diagram existing in at least two topologically unconnected regions.
		The study of the formation of ice Ih to ice XII contributes valuable clues to the understanding of water amorphisation under pressure.
	www.ill.fr /AR-99/page/41chemistry.htm (841 words)

	New ice forms reshape ice research world
		High-density and low-density amorphous, or non-crystalline, ice are among the more than one dozen known ice forms.
		Many scientists believe that these two ice forms are the low-temperature manifestations of two different states of liquid water, and that the transition between the two forms is sudden; that is, their density is discontinuous.
		The researchers discovered these new ice forms while conducting lengthy experiments with the high-density form of amorphous ice supplied by the National Research Council in Ottawa, Canada.
	www.anl.gov /Media_Center/Frontiers/2004/c4facil.html (387 words)

	HIGH PRESSURE CRYONICS
		Amorphous ice or vitrified cryoprotectant mixture can change from a vitreous liquid to a vitreous solid at a glass transition temperature (upon sufficiently rapid cooling) or at a glass transition pressure (upon sufficiently rapid application of pressure).
		Viability at high pressure is reduced by increased fat rigidity in cell membranes (which is why deep-sea organisms have more unsaturated fat in their membranes) and proteins become inactivated by agglutination of water molecules around charged particles and by osmotic effects.
		The ice crystals were formed at high pressure, cooled to liquid nitrogen temperature and removed from the pressure vessel at -196ºC in a metastable state and X-rays were taken.
	www.benbest.com /cryonics/pressure.html (4971 words)

	Re: Ice
		Its structure is characterized by a doubled occupancy of the stabilizing interstitial location that was found in high density amorphous ice, HDA.
		As would be expected for a thermally activated unlocking of the stabilizing "interstitial," the transition from VHDA to LDA (low-density amorphous ice) is very sharp.
		Although its higher density makes VHDA a better candidate than HDA for a physical manifestation of the second putative liquid phase of water, as for the HDA case, the VHDA to LDA transition also appears to be kinetically controlled.
	www.lns.cornell.edu /spr/2002-12/msg0046453.html (386 words)

	The Preparation and Structures of Hydrogen Ordered Phases of Ice -- Salzmann et al. 311 (5768): 1758 -- Science
		The pathways of preparation of DCl-doped ices V and XII are indicated by arrows.
		Ice V was produced by isobarically heating ice Ih to 250 K at 0.5 GPa.
		Pure ice XII was crystallized from high-density amorphous ice by isobaric heating at 1.2 GPa at 11 K min
	www.sciencemag.org /cgi/content/figsonly/311/5768/1758 (649 words)

	Water anomalies
		Water is an excellent solvent due to its polarity, high dielectric constant and small size, particularly for polar and ionic compounds and salts.
		The ‘Structural’ bounds indicate where water is more disordered when compressed, the ‘Dynamic’ bounds indicate where diffusion increases with density, and the ‘Thermodynamic’ bounds show where there is a temperature of maximum density; with the data from [169] shifted upwards 38 K to give the correct temperature of maximum density under standard pressure.
		Note that ice, in contrast, is a very poor solvent and this may be made use of when purifying water (for example, degassing) using successive freeze-thaw cycles.
	www.lsbu.ac.uk /water/anmlies.html (1336 words)

	Summary, Amorphous and Crystalline Ice Growth (Site not responding. Last check: 2007-10-26)
		The simulations will focus on ice growth, both amorphous and crystalline, and will be coupled with laboratory experiments using atomic force microscopy, molecular beams and IR reflection spectroscopy.
		Studies of amorphous ice can, furthermore, give valuable insight into the many perplexing properties of liquid water.
		A method for systematic analysis of many-body correlations in the ordering of water molecules in amorphous ice, liquid water and around defects in crystalline ice will be developed.
	www-theory.chem.washington.edu /~hannes/KDI-Ice/summary.html (335 words)

	Session D28 - Focus Session: Earth and Planetary Materials II.
		This is a quenchable high-pressure phase of ice that upon heating to ~130K at 0 kbar undergoes amorphization.
		They are, respectively, prototypical low and high density hydrogen-ordered forms of ice consisting of one and two interpenetrating hydrogen-bonded networks, that amorphize within each other' stability field.
		The interiors of the ice giant planets, Uranus and Neptune, are composed of a mixture of water, ammonia, and methane.
	flux.aps.org /meetings/YR04/MAR04/baps/abs/S1480.html (2029 words)

	PCCP Articles (Site not responding. Last check: 2007-10-26)
		We report in situ density values of amorphous ice obtained between 0.3 and 1.9 GPa and 144 to 183 K. Starting from high-density amorphous ice made by pressure-amorphizing hexagonal ice at 77 K, samples were heated at a constant pressure until crystallization to high-pressure ices occurred.
		Densities of amorphous ice were calculated from those of high-pressure ice mixtures and the volume change on crystallization.
		0.8 GPa the density increase is dominated to a large extent by reversible elastic compression.
	www.rsc.org /Publishing/Journals/CP/article.asp?doi=b510168a (387 words)

Try your search on: Qwika (all wikis)