scholarly journals The Internal Structure and Ice Crystallography of Seasonal Frost Mounds

1985 ◽  
Vol 31 (108) ◽  
pp. 157-162 ◽  
Author(s):  
W. H. Pollard ◽  
H. M. French
Keyword(s):  
Crystal Growth ◽  
Internal Structure ◽  
Active Layer ◽  
Growth Mechanism ◽  
Basal Plane ◽  
Ice Core ◽  
Ice Crystals ◽  
Rapid Freezing ◽  
Axis Direction ◽  
Primary Growth

AbstractThe crystal character of the ice core within frost blisters supports the hypothesis that groundwater injection into residual zones of the active layer followed by rapid freezing is the primary growth mechanism for these features. The ice core is characterized by an upper zone of relatively small randomly arranged equigranular ice crystals which change with increasing depth to columnar anhedral crystals, commonly exceeding 200 mm in length, and with crystal diameters ranging between 25 and 35 mm. Petrofabric analyses show that the c-axis orientations are normal to crystal elongations, with crystal growth along the basal plane in an a-axis direction. These observations eliminate ice segregation as a possible growth mechanism, thereby distinguishing seasonal frost mounds from palsas.

scholarly journals The Internal Structure and Ice Crystallography of Seasonal Frost Mounds

1985 ◽  
Vol 31 (108) ◽  
pp. 157-162 ◽  
Author(s):  
W. H. Pollard ◽  
H. M. French
Keyword(s):  
Crystal Growth ◽  
Internal Structure ◽  
Active Layer ◽  
Growth Mechanism ◽  
Basal Plane ◽  
Ice Core ◽  
Ice Crystals ◽  
Rapid Freezing ◽  
Axis Direction ◽  
Primary Growth

AbstractThe crystal character of the ice core within frost blisters supports the hypothesis that groundwater injection into residual zones of the active layer followed by rapid freezing is the primary growth mechanism for these features. The ice core is characterized by an upper zone of relatively small randomly arranged equigranular ice crystals which change with increasing depth to columnar anhedral crystals, commonly exceeding 200 mm in length, and with crystal diameters ranging between 25 and 35 mm. Petrofabric analyses show that thec-axis orientations are normal to crystal elongations, with crystal growth along the basal plane in ana-axis direction. These observations eliminate ice segregation as a possible growth mechanism, thereby distinguishing seasonal frost mounds from palsas.

scholarly journals Crystal growth rates in polar firn

1993 ◽  
Vol 18 ◽  
pp. 208-210
Author(s):  
Hitoshi Shoji ◽  
Atau Mitani ◽  
Kohji Horita ◽  
Chester C. Langway
Keyword(s):  
Growth Rate ◽  
Plastic Deformation ◽  
Crystal Growth ◽  
Growth Rates ◽  
Strain Field ◽  
Crystal Size ◽  
Ice Core ◽  
Transformation Process ◽  
Ice Crystals ◽  
Air Bubbles

Continuous crystal-size measurements made on the G6 Antarctic ice core (100m deep) show enhanced growth rates above a depth of 30 m (Zone 1) and in the interval between 70 and 80 m (Zone 2). Crystal growth in Zone 1 most probably takes place by a process of sublimation and condensation. The higher growth rate in Zone 2 is most probably related to the pore close-off transformation process in which a non-uniform strain field is created to form air bubbles by plastic deformation and “cannibalization” of individual ice crystals.

scholarly journals Crystal growth rates in polar firn

1993 ◽  
Vol 18 ◽  
pp. 208-210 ◽  
Author(s):  
Hitoshi Shoji ◽  
Atau Mitani ◽  
Kohji Horita ◽  
Chester C. Langway
Keyword(s):  
Growth Rate ◽  
Plastic Deformation ◽  
Crystal Growth ◽  
Growth Rates ◽  
Strain Field ◽  
Crystal Size ◽  
Ice Core ◽  
Transformation Process ◽  
Ice Crystals ◽  
Air Bubbles

Continuous crystal-size measurements made on the G6 Antarctic ice core (100m deep) show enhanced growth rates above a depth of 30 m (Zone 1) and in the interval between 70 and 80 m (Zone 2). Crystal growth in Zone 1 most probably takes place by a process of sublimation and condensation. The higher growth rate in Zone 2 is most probably related to the pore close-off transformation process in which a non-uniform strain field is created to form air bubbles by plastic deformation and “cannibalization” of individual ice crystals.

scholarly journals Influence of the ice growth rate on the incorporation of gaseous HCl

2004 ◽  
Vol 4 (11/12) ◽  
pp. 2513-2519 ◽  
Author(s):  
F. Domine ◽  
C. Rauzy
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Growth Mechanism ◽  
Laboratory Experiments ◽  
Ice Crystals ◽  
Ice Growth ◽  
A Value ◽  
Physical Variables ◽  
Hcl Concentration ◽  
Cloud Ice

Abstract. Ice crystals were grown in the laboratory at −15°C, at different growth rates and in the presence of a partial pressure of HCl of 1.63×10-3 Pa, to test whether the ice growth rate influences the amount of HCl taken up, XHCl, as predicted by the ice growth mechanism of Domine and Thibert (1996). The plot of HCl concentration in ice as a function of growth rate has the aspect predicted by that mechanism: XHCl decreases with increasing growth rate, from a value that depends on thermodynamic equilibrium to a value that depends only on kinetic factors. The height of the growth steps of the ice crystals is determined to be about 150 nm from these experiments. We discuss that the application of these laboratory experiments to cloud ice crystals and to snow metamorphism is not quantitatively possible at this stage, because the physical variables that determine crystal growth in nature, and in particular the step height, are not known. Qualitative applications are attempted for HCl and HNO3 incorporation in cloud ice and snowpack crystals.

scholarly journals Influence of the ice growth rate on the incorporation of gaseous HCl

2004 ◽  
Vol 4 (4) ◽  
pp. 4719-4736 ◽  
Author(s):  
F. Domine ◽  
C. Rauzy
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Growth Mechanism ◽  
Laboratory Experiments ◽  
Ice Crystals ◽  
Ice Growth ◽  
A Value ◽  
Physical Variables ◽  
Hcl Concentration ◽  
Cloud Ice

Abstract. Ice crystals were grown in the laboratory at −15°C, at different growth rates and in the presence of a partial pressure of HCl of 1.63×10−3 Pa, to test whether the ice growth rate influences the amount of HCl taken up, XHCl, as predicted by the ice growth mechanism of Domine and Thibert (1996). The plot of HCl concentration in ice as a function of growth rate has the aspect predicted by that mechanism: XHCl decreases with increasing growth rate, from a value that depends on thermodynamic equilibrium to a value that depends only on kinetic factors. The height of the growth steps of the ice crystals is determined to be about 1.5 nm from these experiments. We discuss that the application of these laboratory experiments to cloud ice crystals and to snow metamorphism is not quantitatively possible at this stage, because the physical variables that determine crystal growth in nature, and in particular the step height, are not known. Qualitative applications are attempted for HCl and HNO3 incorporation in cloud ice and snowpack crystals.

Montmorillonite Dendrites

1974 ◽  
Vol 32 ◽  
pp. 454-455
Author(s):  
Necip Güven ◽  
Rodney W. Pease
Keyword(s):  
Crystal Growth ◽  
Growth Mechanism ◽  
Growth Front ◽  
Morphological Features ◽  
Dendritic Crystal ◽  
Crystal Growth Mechanism

Morphological features of montmorillonite aggregates in a large number of samples suggest that they may be formed by a dendritic crystal growth mechanism (i.e., tree-like growth by branching of a growth front).

Growth mechanism of small ice crystals

1965 ◽  
Vol 11 (113) ◽  
pp. 1093-1093 ◽  
Author(s):  
J. Hallett
Keyword(s):  
Growth Mechanism ◽  
Ice Crystals

scholarly journals Synthetic insect antifreeze peptides modify ice crystal growth habit

CrystEngComm ◽  
2017 ◽  
Vol 19 (16) ◽  
pp. 2163-2167 ◽  
Author(s):  
Charles H. Z. Kong ◽  
Ivanhoe K. H. Leung ◽  
Vijayalekshmi Sarojini
Keyword(s):  
Crystal Growth ◽  
Small Molecule ◽  
Growth Habit ◽  
Antifreeze Protein ◽  
Ice Crystals ◽  
Ice Crystal ◽  
Antifreeze Peptides ◽  
Antifreeze Activity

Synthetic antifreeze peptides based on the hyperactive antifreeze protein modify the shape of ice crystals and show enhanced antifreeze activity with the addition of a small molecule.

Dry Ice Self-Pressurised Rapid Freezing (DryIce SPRF): all you need to cool for cryofixation of nematodes is dry ice

Nematology ◽  
2021 ◽  
pp. 1-17
Author(s):  
Myriam Claeys ◽  
Vladimir V. Yushin ◽  
Wim Bert
Keyword(s):  
Crystalline State ◽  
Medium Composition ◽  
Ice Crystals ◽  
Rapid Freezing ◽  
High Pressure Freezing ◽  
Dry Ice ◽  
Transmission Electron ◽  
State Of Water ◽  
Pressure Medium ◽  
Excellent Preservation

Summary Cryofixation immediately arrests all biochemical, physiological and dynamic processes underway in the sample in their present state, resulting in both excellent preservation of the specimen’s ultrastructure and its antigenicity. Cryofixation involves extremely rapid cooling of specimens, creating an amorphous, or ‘non-crystalline’, state of water containing no detectable ice crystals, a process dependent on pressure, medium composition and temperature. Self-Pressurised Rapid Freezing (SPRF) employs plunge freezing of specimens in a sealed copper tube into a cryogen such as nitrogen slush (−210°C), liquid nitrogen (−196°C), ethane (−183°C) or propane (−120°C). In this study we have explored the use of SPRF with cooled acetone on dry ice (−80°C) as the cryogen, a method named DryIce SPRF. Although with this relatively high temperature amorphous water cannot be formed, we have demonstrated that the ultrastructural and antigenicity results after DryIce SPRF on Caenorhabditis elegans are perfectly comparable with those achieved using High Pressure Freezing and SPRF. Thus, with sufficient pressure optimal results, with ice crystals below the resolution of transmission electron microscopy, can be achieved even at −78°C. Furthermore, a huge advantage of DryIce SPRF over other techniques is its use of affordable, easily available and safe products.

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