The density, viscosity, vapor pressure, melting point and flash point of a liquid propellant: 1-(2-azidoethyl) pyrrolidine

AbstractSome features around the perimeter of the Balgesvarri plateau ice cap are described. Sorted stone circles were found beneath a slowly retreating ice margin, the basal ice in this area appears to be below the pressure-melting point. No absolute dating of features was possible but a relative chronology is suggested.

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The Berkner Island (Antarctica) ice-core drilling project

Annals of Glaciology ◽

10.3189/172756407786857758 ◽

2007 ◽

Vol 47 ◽

pp. 115-124 ◽

Cited By ~ 28

Author(s):

Robert Mulvaney ◽

Olivier Alemany ◽

Philippe Possenti

Keyword(s):

Melting Point ◽

Ice Core ◽

Ice Sheet ◽

Austral Summer ◽

Core Drilling ◽

Drilling Operation ◽

Drilling Technology ◽

Pressure Melting ◽

Small Team ◽

Drilling Project

AbstractWe describe a project to retrieve a 948m deep ice core from Berkner Island, Antarctica. Using relatively lightweight logistics and a small team, the drilling operation over three austral summer seasons used electromechanical drilling technology, described in detail, from a covered shallow pit and a fluid-filled borehole. A basal temperature well below pressure-melting point meant that no drilling problems were encountered when approaching the bed and the borehole penetrated through to the base of the ice sheet, and sediment was retrieved from beneath the ice.

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A search in north Greenland for a new ice-core drill site

Journal of Glaciology ◽

10.3189/s0022143000003245 ◽

1997 ◽

Vol 43 (144) ◽

pp. 300-306 ◽

Cited By ~ 2

Author(s):

D. Dahl-Jensen ◽

N.S. Gundestrup ◽

K. Keller ◽

S.J. Johnsen ◽

S.P. Gogineni ◽

...

Keyword(s):

Melting Point ◽

Flow Model ◽

Accumulation Rate ◽

Ice Core ◽

Ice Flow ◽

Basal Ice ◽

Drill Site ◽

Radio Echo Sounding ◽

Pressure Melting ◽

North Greenland

AbstractA new deep ice-core drilling site has been identified in north Greenland at 75.12° N, 42.30° W, 316 km north-northwest (NNW) of the GRIР drill site on the summit of the ice sheet. The ice thickness here is 3085 m; the surface elevation is 2919 m.The North GRIP (NGRIP) site is identified so that ice of Eemian age (115–130 ka BP,calendar years before present) is located as far above bedrock as possible and so the thickness of the Eemian layer is as great as possible. An ice-flow model, similar to the one used to date the GRIP ice core, is used to simulate the flow along the NNW-trending ice ridge. Surface and bedrock elevations, surface accumulation-rate distribution and radio-echo sounding along the ridge have been used as model input.The surface accumulation rate drops from 0.23 m fee equivalent year−1 at GRIP to 0.19 m ice equivalent year−1 50 km from GRIP. Over the following 300km the accumulation is relatively constant, before it starts decreasing again further north. Ice thicknesses up to 3250 m bring the temperature of the basal ice up to the pressure-melting point 100–250 km from GRIP. The NGRIP site islocated 316 km from GRIP in a region where the bedrock is smooth and the accumulation rate is 0.19 m ice equivalent year−1. The modeled basal ice here has always been a few degrees below the pressure-melting point. Internal radio-echo sounding horizons can be traced between the GRIP and NGRIP sites, allowing us to date the ice down to 2300 m depth (52 ka BP). An ice-flow model predicts that the Eemian-age ice will be located in the depth range 2710–2800 m, which is 285 m above the bedrock. This is 120 m further above the bedrock, and the thickness of the Eemian layer of ice is 20 m thicker, than at the GRIP ice-core site.

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A search in north Greenland for a new ice-core drill site

Journal of Glaciology ◽

10.1017/s0022143000003245 ◽

1997 ◽

Vol 43 (144) ◽

pp. 300-306 ◽

Cited By ~ 54

Author(s):

D. Dahl-Jensen ◽

N.S. Gundestrup ◽

K. Keller ◽

S.J. Johnsen ◽

S.P. Gogineni ◽

...

Keyword(s):

Melting Point ◽

Flow Model ◽

Accumulation Rate ◽

Ice Core ◽

Ice Flow ◽

Basal Ice ◽

Drill Site ◽

Radio Echo Sounding ◽

Pressure Melting ◽

North Greenland

AbstractA new deep ice-core drilling site has been identified in north Greenland at 75.12° N, 42.30° W, 316 km north-northwest (NNW) of the GRIР drill site on the summit of the ice sheet. The ice thickness here is 3085 m; the surface elevation is 2919 m.The North GRIP (NGRIP) site is identified so that ice of Eemian age (115–130 ka BP,calendar years before present) is located as far above bedrock as possible and so the thickness of the Eemian layer is as great as possible. An ice-flow model, similar to the one used to date the GRIP ice core, is used to simulate the flow along the NNW-trending ice ridge. Surface and bedrock elevations, surface accumulation-rate distribution and radio-echo sounding along the ridge have been used as model input.The surface accumulation rate drops from 0.23 m fee equivalent year−1at GRIP to 0.19 m ice equivalent year−150 km from GRIP. Over the following 300km the accumulation is relatively constant, before it starts decreasing again further north. Ice thicknesses up to 3250 m bring the temperature of the basal ice up to the pressure-melting point 100–250 km from GRIP. The NGRIP site islocated 316 km from GRIP in a region where the bedrock is smooth and the accumulation rate is 0.19 m ice equivalent year−1. The modeled basal ice here has always been a few degrees below the pressure-melting point. Internal radio-echo sounding horizons can be traced between the GRIP and NGRIP sites, allowing us to date the ice down to 2300 m depth (52 ka BP). An ice-flow model predicts that the Eemian-age ice will be located in the depth range 2710–2800 m, which is 285 m above the bedrock. This is 120 m further above the bedrock, and the thickness of the Eemian layer of ice is 20 m thicker, than at the GRIP ice-core site.

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Modelling binge–purge oscillations of the Laurentide ice sheet using a plastic ice sheet

Annals of Glaciology ◽

10.3189/172756408784700635 ◽

2008 ◽

Vol 48 ◽

pp. 177-182 ◽

Cited By ~ 1

Author(s):

H.C. Steen-Larsen ◽

D. Dahl-Jensen

Keyword(s):

Melting Point ◽

Accumulation Rate ◽

Ice Core ◽

Ice Sheet ◽

Laurentide Ice Sheet ◽

Climate Feedbacks ◽

Heinrich Events ◽

Basal Sliding ◽

Pressure Melting ◽

Temperature Records

AbstractA simple combined heat and ice-sheet model has been used to calculate temperatures at the base of the Laurentide ice sheet. We let the ice sheet surge when the basal temperature reaches the pressure-melting temperature. Driving the system with the observed accumulation and temperature records from the GRIP ice core, Greenland, produces surges corresponding to the observed Heinrich events. This suggests that the mechanism of basal sliding, initiated when the basal temperature reaches the melting point, can explain the surges of the Laurentide ice sheet. This study highlights the importance of the surface temperature and accumulation rate as a means of forcing the timing and strength of the Heinrich events, thus implying important ice-sheet climate feedbacks.

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Antimony Pentafluoride: Density Melting Point and Vapor Pressure

The Journal of Physical Chemistry ◽

10.1021/j150557a030 ◽

1957 ◽

Vol 61 (11) ◽

pp. 1574-1575 ◽

Cited By ~ 12

Author(s):

Charles J. Hoffman ◽

William L. Jolly

Keyword(s):

Melting Point ◽

Vapor Pressure ◽

Antimony Pentafluoride

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Spatial variations in heat at the base of the Antarctic ice sheet from analysis of the thermal regime above subglacial lakes

Journal of Glaciology ◽

10.1017/s0022143000003488 ◽

1996 ◽

Vol 42 (142) ◽

pp. 501-509 ◽

Cited By ~ 48

Author(s):

Martin J. Siegert ◽

Julian A. Dowdeswell

Keyword(s):

Heat Flux ◽

Melting Point ◽

Thermal Model ◽

Large Scale ◽

Ice Sheet ◽

Geothermal Heat ◽

Vertical Advection ◽

Basal Sliding ◽

Pressure Melting ◽

Subglacial Lakes

AbstractAntarctic subglacial lakes provide аn important boundary condition for thermal analysis of the ice sheet in that the basal ice temperature over lakes may be assumed to be at the pressure-melting point. We have used a one-dimensional vertical heat-transfer equation to determine theoretical temperature values for the ice-sheet base above 77 subglacial lakes identified from airborne radio-echo-sounding data covering 50% of Antarctica. Variations in our temperature results to below the pressure-melting temperature over lakes are due to either our estimate of the geothermal heat flux or a neglect of heat derived from (a) internal ice deformation and (b) basal sliding, in the thermal model. Our results indicate that, when the geothermal heat flux is set at 54 m W m−2, the ice-sheet base above 70% of the known Antarctic subglacial lakes is calculated to be at the pressure-melting value. These lakes are located mainly around Dome C, Ridge B and Vostok station. For the ice sheet above subglacial lakes located hundreds of kilometres from the ice divide, using the same thermal model, loss of heat due to vertical advection is calculated to be relatively high. In such regions, if the ice-sheet base is at the pressure-melting point, heat lost due to vertical advection must be supplemented by heat from other sources. For the three lakes beneath Terre Adélie and George V Land, for instance, the basal thermal gradient calculated to produce pressure melting at the ice-sheet base is equivalent to 1.5–2 times the value obtained when 54 m W m−2of geothermal heat is used as the sole basal thermal component. We suggest that, as distance from the ice divide increases, so too does the amount of heat due to internal ice deformation and basal sliding. Moreover, by considering the ice-sheet basal thermal characteristics above subglacial lakes which lie on the same ice flowline, we demonstrate empirically that the heat due to these horizontal ice-motion terms varies pseudo-exponentially with distance from the ice divide. The location along a flowline where a rapid increase in the basal heat gradient is calculated may correspond to the onset of large-scale basal sliding.

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Temperature Measurements in Athabasca Glacier, Alberta, Canada

Journal of Glaciology ◽

10.3189/s0022143000022036 ◽

1971 ◽

Vol 10 (60) ◽

pp. 339-349 ◽

Cited By ~ 2

Author(s):

W. S. B. Paterson

Keyword(s):

Melting Point ◽

Hydrostatic Pressure ◽

Water Content ◽

Melting Temperature ◽

Small Difference ◽

Temperature Measurements ◽

Air Bubbles ◽

Average Difference ◽

Ablation Area ◽

Pressure Melting

AbstractThe temperature in the ablation area of Athabasca Glacier is about —0.5°C at a depth of 10 m. Below 17 m the temperature is slightly below the calculated pressure melting point (average difference 0.01 deg) in some places. Heat produced by ice deformation is calculated as a function of depth in two bore holes. Only in about the lower half of the glacier thickness is this heat sufficient to maintain the ice at the observed temperature as the hydrostatic pressure is reduced by ablation. Freezing of water within the ice must provide heat for this purpose elsewhere in the glacier; it must also provide heat to maintain the deeper ice close to the melting point even though the 10 m temperature is negative. The minimum water content needed is estimated to be between 0.5 and 1%. It is argued that most of this water must be water trapped between grains when the ice formed from firn. The small difference from the pressure melting temperature measured below 17 m probably arises either from impurities or because, as a result of heat supplied for pressure-melting of ice around air bubbles, the ice is at the melting point corresponding to the bubble pressure rather than to the hydrostatic pressure.

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Phase Behavior and Its Effects on Reactions in Liquid and Supercritical Carbon Dioxide

Green Chemistry Using Liquid and Supercritical Carbon Dioxide ◽

10.1093/oso/9780195154832.003.0005 ◽

2004 ◽

Author(s):

Lynnette A. Blanchard ◽

Gang Xu

Keyword(s):

Carbon Dioxide ◽

Melting Point ◽

Vapor Pressure ◽

Phase Behavior ◽

Critical Point ◽

Pressure Curve ◽

Light Component ◽

Vapor Pressure Curve ◽

Solid Liquid ◽

Liquid Vapor

Carbon dioxide, either as an expanded liquid or as a supercritical fluid, may be a viable replacement for a variety of conventional organic solvents in reaction systems. Numerous studies have shown that many reactions can be conducted in liquid or supercritical CO2 (sc CO2) and, in some cases, rates and selectivities can be achieved that are greater than those possible in normal liquid- or gas-phase reactions (other chapters in this book; Noyori, 1999; Savage et al., 1995). Nonetheless, commercial exploitation of this technology has been limited. One factor that contributes to this reluctance is the extremely complex phase behavior that can be encountered with high-pressure multicomponent systems. Even for simple binary systems, one can observe multiple fluid phases, as shown in Figure 1.1. The figure shows the pressure–temperature (PT) projection of the phase diagram of a binary system, where the vapor pressure curve of the light component (e.g., CO2) is the solid line shown at temperatures below TB. It is terminated by its critical point, which is shown as a solid circle. The sublimation curve, melting curve, and vapor pressure curve of the pure component 2 (say, a reactant that is a solid at ambient conditions) are the solid lines shown at higher temperatures on the right side of the diagram; that is, the triple point of this compound is above TE. The solid might experience a significant melting point depression when exposed to CO2 pressure [the dashed–dotted solid/liquid/vapor (SLV) line, which terminates in an upper critical end point (UCEP)]. For instance, naphthalene melts at 60.1 °C under CO2 pressure (i.e., one might observe a three-phase solid/liquid/vapor system), even though the normal melting point is 80.5 °C (McHugh and Yogan, 1984). To complicate things even further, there will be a region close to the critical point of pure CO2 where one will observe three phases as well, as indicated by the dashed–dotted SLV line that terminates at the lower critical end point (LCEP). The dotted line connecting the critical point of the light component and the LCEP is a vapor/liquid critical point locus.

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