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  • 1955-1959  (7)
  • 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-202-59
    In: Research report / Cold Regions Research and Engineering Laboratory, 59
    Description / Table of Contents: Summary: The deflection expression of an infinite plate subjected to a concentrated force is used with the "method of images" to obtain solutions for 6 plates with simply supported edges. The semi-infinite plate, the wedge-shaped plate, and its special case, the rectangular corner plate, are solved in closed form; and the infinite strip, the semi-infinite strip, and the rectangular plate are solved as rapidly convergent series. Behavior under a concentrated force is studied in more detail for the semi-infinite plate and the rectangular corner plate. Relationships for obtaining bending moments, shear forces and reaction distributions as well as derivatives of the kei-function with respect to 𝗋 and 𝛳 are given in the appendices.
    Type of Medium: Series available for loan
    Pages: iv, 12, [2] Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 59
    Language: English
    Note: CONTENTS Preface Introduction and statement of the problem Solution of the boundary value problems for simply supported boundaries Semi-infinite plate Wedge-shaped plate Rectangular corner plate Infinite strip Semi-infinite strip Rectangular plate Remarks on the problem of arbitrary load distribution References Appendix A Appendix B
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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-202-55
    In: Research report / Cold Regions Research and Engineering Laboratory, 55
    Description / Table of Contents: Summary: Experiments were performed to investigate the processes involved in the formation of sorted patterns which occur naturally in unconsolidated sandy gravel deposits covering the edge of the ice cap southeast of Thule, northwest Greenland. Four different glacier ice surfaces were covered with various thicknesses of sandy gravel in order to observe the effect of differential melting on the formation of sorted patterns. The different stages of pattern formation were recorded by photographs taken at 7-day intervals. A thin gravel cover of 2 in. allowed more rapid melting than did a cover of 6 in., with the result that depressions and mounds were formed. Coarse particles were segregated in the depressions by natural sorting of the various particle sizes when set in motion by differential melting and resulting uneven collapse of the gravel cover. The sorting produced well-developed stone rings in three of the areas, caused directly by the differential insulation provided by the gravel cover. In the fourth area a uniform gravel cover over a smooth ice surface produced no sorted nets, although a poorly developed stone stripe was formed in a melt-stream channel. A stone stripe was also formed in a stream channel cut into the ice along the edge of the test area. This stripe was composed of coarse particles which rolled down from the better insulated heights of the test area. It is therefore possible that sorted nets and stripes occurring naturally in the moraine deposits on the edge of the ice cap could have been formed by mechanical sorting induced by differential melting of the ice under a non-uniform layer of sandy gravel.
    Type of Medium: Series available for loan
    Pages: iv, 15 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 55
    Language: English
    Note: CONTENTS Preface Summary Introduction Procedure Preparation of test plots Measurements of ice and gravel surfaces Composition of the gravel covering Results Sorting in a smooth layer of sandy gravel over an uneven ice surface Sorting in a uniform layer of sandy gravel over depressions in the ice surface Sorting in a uniform layer of sandy gravel over a uniform ice surface Sorting in a non-uniform layer of sandy gravel over a uniform ice surface Discussion and recommendations Conclusions References
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  • 3
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    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
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  • 4
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    Series available for loan
    Wilmette, Ill. : Snow Ice and Permafrost Research Establishment, Corps of Engineers, U.S. Army
    Associated volumes
    Call number: ZSP-202-47
    In: Research report / Cold Regions Research and Engineering Laboratory, 47
    Description / Table of Contents: Summary: Various mechanical properties such as strength, elastic modulus, and density of TUTO tunnel and ramp ice were determined. Results of unconfined compressive strength, ring tensile strength, and flexural strength tests are given. Photographs of included bubbles and grain size and shape are shown for each of six types of ice tested. Petrofabric diagrams for each type of ice are included. No significant differences in strength were found between horizontal and vertical cores in the ice tunnel, although differences between types of ice are noted. Crushing strength values found for tunnel ice generally fit the empirical equation relating crushing strength to density which was found for high-density snows (Butkovich, 1956a). However the values for ramp ice do not fit the equation when the average density values are used, probably due to the layering. The empirical equation relating ring tensile strength to density of high-density snows (ibid.) gives results approximately 20% greater than those obtained for tunnel ice. It appears that grain size influences the results. Ice with large grains consistently gives lower values. Flexural strength of the ramp ice is about half that of the tunnel ice. Comparing these results with the ring tensile values leads to the conclusion that the beams tend to fail in the lowest-density (mostly bubbly) bands. Temperature curves as a function of depth into the wall and along the tunnel length are presented. A 30-day study of deformation in a 100 x 30 ft room at 650 ft. into the tunnel indicated that the room is closing primarily by a block action, with rates of closure being less only very near the walls.
    Type of Medium: Series available for loan
    Pages: iv, 17 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 47
    Language: English
    Note: CONTENTS Preface Summary Introduction Strength Crushing strength Ring tensile strength Flexural strength Static modulus of elasticity Dynamic modulus of elasticity Density of tunnel and ramp ice Tunnel temperature measurements Crystal size, bubble size, and ice fabrics Deformation measurements Discussion of strength test results References
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  • 5
    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-202-51
    In: Research report / Cold Regions Research and Engineering Laboratory, 51
    Description / Table of Contents: Summary: The study was made in order to simulate the deformation of a tunnel in glacier ice and compare the results with the theoretical value derived from compression or tension tests. The plastic deformation of commercial polycrystalline ice and manufactured snow-ice was determined by measuring the discharge of oil from the cavity of closed hollow ice cylinders subjected to high external pressure in an oil-filled pressure chamber. The deformation vs time curves were similar to those obtained in compression or tension tests. The relationships between minimum strain rate and applied pressure, or between minimum strain rate and the circumferential stress at the surface of the inner cavity, were found to differ from the power law ϵ ̇= ασⁿ, the value of n being an increasing function of stress. Analysis of time deformation curves indicates that viscoelastic models proposed by former investigators do not apply to the mechanism of the plastic deformation of ice.
    Type of Medium: Series available for loan
    Pages: iv, 10 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 51
    Language: English
    Note: CONTENTS Preface Summary Introduction Apparatus Specimens Experimental procedures and results Analysis of the data Discussion References
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  • 6
    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-202-52
    In: Research report / Cold Regions Research and Engineering Laboratory, 52
    Description / Table of Contents: Summary: The results of studies on the physical properties of fog whiteout, as it occurred at Site 2 on the Greenland Ice Cap in the summers of 1956 and 1957, are reported and compared with the results of other studies; the instruments, methods of measurement, and data-reduction techniques used are described; and attempts at dissipating whiteout by AgI (silver iodide) seeding are discussed briefly. Emphasis was given to measurements of fog-particle size distribution, liquid-water content, relative humidity, visibility, and atmospheric nuclei. The data are tabulated. The synoptic situations for 2 selected cases of fog whiteout at relative humidities of less than 100% (possibly because of the presence of salt solutions) are described; and the balance between the rate at which water is made available in the air as it is lifted over the Ice Cap and the rate of water flux to the snow surface is computed using various equations. Efforts at fog dispersal by AgI seeding from the ground were inconclusive.
    Type of Medium: Series available for loan
    Pages: iv, 18, A1 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 52
    Language: English
    Note: CONTENTS Preface Summary Introduction Definition of whiteout Scope of this study Instrumentation and observations Location of project: Fog particle measurements Atmospheric humidity measurements Visibility measurements Air temperature measurements Radiation measurements Atmospheric nuclei Observations of fog whiteout Conditions prior to onset of whiteout Conditions at time of arrival and during whiteout Micro-structure of fog whiteout Analysis of moisture balance during two selected cases Synoptic situation for case 1 Synoptic situation for case 2 Computations Attempts at fog whiteout dispersal References Appendix A - Freezing nuclei observations Appendix B - Absolute humidity gradient data
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  • 7
    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-202-46
    In: Research report / Cold Regions Research and Engineering Laboratory, 46
    Description / Table of Contents: Summary: The results of studies in the summer of 1957 on ice samples taken from the ice tunnel at TUTO, core samples obtained by drilling in the ice cap at Site 2, and snow samples, using the transverse vibration method and a new portable meter, are reported. Young's modulus was determined from the resonance frequency of flexural vibrations of samples cut in the form of rectangular bars; the loss factor was measured from damping; and the coefficient of viscosity calculated using the Maxwell model. The modulus of elasticity of samples of a density from 0.917 - 0.90 g/cm^3 (tunnel ice) decreased sharply with slight deviations of the density from that of pure ice. At densities from 0.90 - 0.50 g/cm^3 (deep-pit and drill-core samples) the relation between the modulus of elasticity and density was linear, while in the density range from 0.50-0.25 g/cm^3 (surface snow) the modulus of elasticity decreased exponentially. The viscosity-density relation of the samples was similar to that of elasticity vs density. Young's modulus increased slightly with decreasing temperature, while viscosity increased exponentially. The activation energy was calculated as 18.7 kcal/mol for old ice-cap ice, 13.9 kcal/mol for tunnel ice with elongated bubbles, and 13.5 kcal/mol for super-imposed ice.
    Type of Medium: Series available for loan
    Pages: v, 29, A4 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 46
    Language: English
    Note: CONTENTS Preface Summary Introduction Principle of measuring the visco-elastic nature of snow and ice by the vibration method Experimental method for determination of visco-elastic properties of snow and ice Visco-elastic properties of tunnel ice Elastic properties of snow samples from the deep pit Elastic properties of core samples obtained by drilling Elastic properties of snow near the ice-cap surface Vertical variation of Young's modulus near the surface Wind-packed snow Peter snow Relation between Young's modulus and density of snow Relation between Young's modulus and density over the range from surface snow to ice Supplementary experiments on the elastic nature of snow and ice at Site 2 Anisotropy of Peter snow Age hardening Temperature dependence of Young's modulus of core ice Viscosity measurement of snow and ice in Greenland Further experiments on the elastic nature of tunnel ice Temperature dependence of Young's modulus Frequency dependence of Young's modulus Further experiments on the viscous nature of tunnel ice Temperature dependence of loss factor Activation energy Frequency dependence of loss factor and viscosity Relation between viscosity and density Conclusions References Appendix: Experimental data
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