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  • 1
    Series available for loan
    Series available for loan
    Wilmette, Ill. : Snow Ice and Permafrost Research Establishment, Corps of Engineers, U.S. Army
    Associated volumes
    Call number: ZSP-202-56
    In: Research report / Cold Regions Research and Engineering Laboratory, 56
    Description / Table of Contents: Summary: The results of laboratory creep tests in a shear apparatus at -5°C on 2 x2 x 3/8 in. samples of commercial ice, artificial single crystals, and 6 types of ice from the Greenland Ice Cap, at shear stresses of about 0.5-3 kg/cm^2 are reported. Some uniaxial tests were made at stresses from 6-28 kg/cm^2 to supplement the shear tests. Creep data could usually be represented approximately by one or more linear sections on a log-deformation vs log-time plot. The linear sections of the double logarithmic curve imply a creep curve of the form ε=ct^m where ε is the strain. For all samples tested, except single crystals sheared in easy glide, m averaged 0. 5 for shear deformations up to about 1%, and approached unity for more deformation. For single ice crystals oriented for easy glide, m averaged 1.7, implying a strain softening. Single crystals oriented for hard glide behaved similarly to polycrystals, indicating a rate-controlling process such as dislocation climb. For all but single easy-glide crystals, the minimum creep rate was tangent to the deformation curve at the end of the experiment. Creep rates for single easy-glide crystals were several hundred times larger than for the other crystals, the flow laws being similar.
    Type of Medium: Series available for loan
    Pages: iv, 7 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 56
    Language: English
    Note: CONTENTS Preface Summary Introduction Types of ice Experiments Results Creep curves Flow law References
    Location: AWI Archive
    Branch Library: AWI Library
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  • 2
    Series available for loan
    Series available for loan
    Wilmette, Ill. : Snow Ice and Permafrost Research Establishment, Corps of Engineers, U.S. Army
    Associated volumes
    Call number: ZSP-202-33
    In: Research report / Cold Regions Research and Engineering Laboratory, 33
    Description / Table of Contents: Summary: A series of deformation measurements have been selected for preliminary studies on the plasticity of Greenland glacier ice. The measurements to be reported on were obtained in the Red Rock and TUTO tunnels in Northwest Greenland. Both tunnels were excavated during the summer of 1955 with some additional work done during the summer of 1956. Deformation measurements made up to the end of the 1956 summer season, therefore, are of limited reliability, but certain trends appearing in these data seem worth reporting. The topics discussed are (1) the shearing of an initially vertical peg system at Red Rock, (2) the deformation of core holes at TUTO, and (3) tunnel closure at both sites. These data are analyzed on the basis of laminar flow of the Nye type and certain conclusions are derived.
    Type of Medium: Series available for loan
    Pages: 6 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 33
    Language: English
    Note: CONTENTS Introduction Experimental Analysis The shear of glaciers Tunnel closure Conclusions References
    Location: AWI Archive
    Branch Library: AWI Library
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  • 3
    Series available for loan
    Series available for loan
    Wilmette, Ill. : Snow Ice and Permafrost Research Establishment, Corps of Engineers, U.S. Army
    Associated volumes
    Call number: ZSP-202-41
    In: Research report / Cold Regions Research and Engineering Laboratory, 41
    Description / Table of Contents: Summary: Laboratory experiments on the creep of sifted snow under uniaxial, hydrostatic, and confined-side compressive stresses are described, and the results are discussed on the basis of an additive theory for combined stresses. Stress (4-40 psi) and temperature (-3.6°C to -13.6°C) dependence was investigated for 35 samples (initial density = 0.4 g/cm^3) subjected to uniaxial and hydrostatic stress for 200-sec time increments. Another series of 104 samples (initial densities 0.36-0.63) was subjected to uniaxial, hydrostatic, and confined-side compressive stresses until an arbitrary change in density was reached. In all cases the applied stress ultimately became a shear stress acting between grains, the open structure reacting differently to combined stresses and separate uniaxial stresses. An activation energy of 13,400 cal/mol was obtained from the first group of tests.
    Type of Medium: Series available for loan
    Pages: iv, 12 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 41
    Language: English
    Note: CONTENTS Preface Summary Introduction Experimental General Apparatus Procedure Theoretical relations Additive theory Relationship between tests run for constant change in density and tests for constant time Results and discussion Group I experiments Group II experiments Stress dependence for group II tests Variability Time dependence Activation energy Relations between creep rates under different stress conditions Density dependence Lateral stress for confined-side tests Conclusions References
    Location: AWI Archive
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  • 4
    Publication Date: 1954-10-15
    Print ISSN: 0031-899X
    Electronic ISSN: 1536-6065
    Topics: Physics
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  • 5
    Publication Date: 1959-01-01
    Description: SummaryA series of deformation measurements have been selected for preliminary studies on the plasticity of Greenland glacier ice. The measurements to be reported on were obtained in the Red Rock and TUTO tunnels in north-west Greenland. Both tunnels were excavated during the summer of 1955 with some additional work done during the summer of 1956. Deformation measurements made up to the end of the 1956 summer season, therefore, are of limited reliability, but certain trends appearing in these data seem worth reporting. The topics discussed are (1) the shearing of an initially vertical peg system at Red Rock, (2) the deformation of core holes at TUTO, and (3) tunnel closure at both sites. These data are analysed on the basis of laminar flow of the Nye type and certain conclusions are derived.
    Print ISSN: 0022-1430
    Electronic ISSN: 1727-5652
    Topics: Geography , Geosciences
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  • 6
    Publication Date: 1959-01-01
    Description: Summary A series of deformation measurements have been selected for preliminary studies on the plasticity of Greenland glacier ice. The measurements to be reported on were obtained in the Red Rock and TUTO tunnels in north-west Greenland. Both tunnels were excavated during the summer of 1955 with some additional work done during the summer of 1956. Deformation measurements made up to the end of the 1956 summer season, therefore, are of limited reliability, but certain trends appearing in these data seem worth reporting. The topics discussed are (1) the shearing of an initially vertical peg system at Red Rock, (2) the deformation of core holes at TUTO, and (3) tunnel closure at both sites. These data are analysed on the basis of laminar flow of the Nye type and certain conclusions are derived.
    Print ISSN: 0022-1430
    Electronic ISSN: 1727-5652
    Topics: Geography , Geosciences
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  • 7
    Publication Date: 1955-12-01
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
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