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  • 11
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    Circular plates on elastic, sealed foundations (1963)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-202-118
    In: Research report / Cold Regions Research and Engineering Laboratory, 118
    Description / Table of Contents: Summary: The observation that newly frozen ice sheets, resulting from pools of -water freezing over,- support more than would be predicted by ordinary theory is assessed. A solution is presented for a circular plate on an elastic, sealed foundation. Graphical results are shown for supports at the circumference of the plate. Graphs to obtain moments in a circular plate on an elastic bearing surface, using a sealed or unsealed foundation, are compiled for fixed and simple supports. In reality the foundation may not be completely sealed, calling for discretion in selecting the actual moment. The ability of the refrozen ice sheet to support the extra load is explained by the fact that the water has been sealed between the surface and main sheet of ice and the volume occupied by the water cannot change.
    Type of Medium: Series available for loan
    Pages: iii, 14 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 118
    URL: https://hdl.handle.net/11681/5858
    Language: English
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  • 12
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    Plastic deformation of thick-walled snow-ice cylinders under hydrostatic pressure (1960)
    Wilmette, Ill. : Snow Ice and Permafrost Research Establishment, Corps of Engineers, U.S. Army
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    Call number: ZSP-202-63
    In: Research report / Cold Regions Research and Engineering Laboratory, 63
    Description / Table of Contents: Summary: Experiments have been carried out on the plastic deformation of thick-walled snow-ice cylinders under hydrostatic pressure as a function of pressure and temperature. At constant circumferential stress and temperature the natural strain rate of closure is a constant. This constant varies with the circumferential stress according to a sine function and is exponentially dependent on temperature with an energy of activation of 14.1 kcal/mole at an average circumferential stress of 3.1 kg/cm^2. The mechanism of the plastic flow is in agreement with a mechanism proposed previously, that is, flow between grain boundaries takes place.
    Type of Medium: Series available for loan
    Pages: iv, 7 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 63
    URL: https://hdl.handle.net/11681/2740
    Language: English
    Note: CONTENTS Preface Summary Experimental Materials Apparatus Experimental results Deformation under constant hydrostatic pressure Deformation as a function of hydrostatic pressure Deformation as a function of temperature at constant pressure Discussion References
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  • 13
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    Physical properties and internal structure of Greenland snow (1970)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-202-89
    In: Research report / Cold Regions Research and Engineering Laboratory, 89
    Description / Table of Contents: Abstract: Experiments were carried out near Thule, Greenland, on the correlation between the physical properties and internal structure of snow. About 150 snow samples obtained to 26 m depth were measured for elastic modulus, air permeability, unconfined compressive strength, static compression and creep. The observed density profile curve deviated from the theoretical curve at a depth of 10 m. and density of 0.52 g/cm^3, a value almost equivalent to the limiting density obtainable by simple mechanical packing. Therefore, further densification must proceed through plastic flow in grains. A similar critical depth was observed in the vertical distribution of Young's modulus. A positive correlation was found between Young's modulus and density, and an inverse correlation between average grain diameter and Young's modulus or density. There were reciprocal correlations between air permeability and density or unconfined compressive strength, and between the number of grains and their average diameters. Kozeny's constant of Greenland snow was obtained from air permeability values and the length of peripheries of cross sections of grains. To demonstrate the change of internal structure of snow due to densification, static compression tests of snow cylinders were conducted, and thin sections of snow texture were compared before and after compression. Creep curves of snow cylinders were analyzed using Nutting's formula and are discussed in connection with change of internal structure. Basal slip, buckling, cell or sub-grain formation, recrystallization and grain boundary migration occurring during plastic deformation of snow texture were observed by static compression of thin section snow under the microscope.
    Type of Medium: Series available for loan
    Pages: vi, 32 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 89
    URL: https://hdl.handle.net/11681/5874
    Language: English
    Note: CONTENTS Preface Nomenclature Introduction Experimental methods Density profile and densification Internal structure in typical samples Average grain size obtained from thin section Two-dimensional porosity, total pore periphery and tortuosity Vertical distribution of Young's modulus Air permeability and its structlU'al dependence Porosity dependence Grain size dependence Kozeny's constant for Greenland snow Correlation between air permeability and tortuosity of grains Unconfined compressive strength Static compression and creep in snow under high stresses Microscopic observation of the change in snow textlU'e under compression Literature cited Abstract
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  • 14
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    Analysis of data from a snow profile (1962)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-202-90
    In: Research report / Cold Regions Research and Engineering Laboratory, 90
    Description / Table of Contents: Summary: A new method is presented for extracting more meaningful information from snow profile data which will simplify the study of the permeability of snow. Earlier analyses normally employed statistical methods to determine property variations with depth, with the line of mean values established by the method of least squares. The mean curves derived in this manner may not represent properly the true nature of the snow pack, or aid in understanding the dynamic processes which are in action. The new graphical methods described distinguish the separate effects of densification and thermal metamorphism on permeability, permitting future advances in the analysis. Profile data obtained in 1954 and 1960 are reanalyzed using the new techniques. For a natural polar pack under conditions when no melting occurs and the accumulation is assumed continuous, the following conclusions may be made: permeability for a given density of snow increases with depth and time except possibly near the surface or at depths below 30 m; the rate of permeability change with depth for given densities decreases in a calculable way relative to the density; and, mean permeability changes with depth in a complex manner.
    Type of Medium: Series available for loan
    Pages: iv, 14, A3, B2, C2 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 90
    URL: https://hdl.handle.net/11681/5875
    Language: English
    Note: CONTENTS Preface Summary Introduction Standard methods of data presentation- A class interval method of data presentation Interpretation of the numerical data Interpretation of thin sections Conclusions References Appendix A Appendix B Appendix C
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  • 15
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    Relationship between four ground patterns, structure of the active layer, and type and distribution of ice in the permafrost (1962)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-202-88
    In: Research report / Cold Regions Research and Engineering Laboratory, 88
    Description / Table of Contents: Summary: Four ground patterns were investigated by means of trenches cut in the outwash near Thule, Greenland: circular and linear depressions in unsorted material, polygonal troughs in unsorted material, sorted circles, and irregular mounds and depressions of low relief formed in unsorted finer grained material. Correlation is made between surface pattern, grain size and structure of the active layer, and type and distribution of ground ice for the patterns investigated. Classification of the active layer as disturbed, slightly disturbed, and undisturbed is based on the condition of primary depositional bedding and the presence or absence of vertical sorting. Other features of the active layer, depending upon its type, are an accumulation of fines at the bottom of the active layer and on top of stones, and a siliceous calcareous evaporite on the under surface and clean washed coarser particles beneath the larger stones. Fabric analysis of four kinds of ground ice is presented: ice wedge, relict ice, ice mass, and ice lens, as well as analysis of the contact of ice wedges with relict and mass ice. Practical applications, based on the conclusions, are given for the selection of foundation sites and the location of non-frost-susceptible building materials. NOTE: This is a very large file. Please give your browser several minutes to download the file.
    Type of Medium: Series available for loan
    Pages: viii, 79 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 88
    URL: https://hdl.handle.net/11681/5867
    Language: English
    Note: CONTENTS Preface Summary Introduction Glossary Part 1 : Surface pattern, structure of the active layer, and type and distribution of ground ice in the permafrost Pattern type 1: Circular and linear depressions in unsorted outwash Circular depressions, area 1 Structure of the active layer Ground ice and its relation to surface morphology Linear depressions, area 5 Structure of the active layer Ground ice and its relation to surface morphology Pattern t ype 2 and 3: Polygonal troughs in unsorted outwash and sorted circles or centers of fines Area 3 Structure of the active layer Ground ice and its relation to surface morphology Area 4 Structure of the active layer Ground ice and its relat ion to surface morphology Pattern type 4: Mounds and depressions of low relief in unsorted outwash Area 4a Structure of the active layer Ground ice and its relatiop. to surface morphology Part 2: Ground ice studies Area 1 Lens ice History Appearance of the ice Fabric analysis Wedge ice History Appearance of the ice Fabric analysis Relict ice History Appearance of the ice Fabric analysis Contact between ice wedge and relict ice Ice sockets Area 5 Wedge ice Fabric analysis Relict ice Fabric analysis Area 3 Ice mass History Appearance of the ice Fabric analysis Ice wedge Fabric analysis Contact between ice mass and wedge Appearance of the ice Fabric analysis Summary and conclusions Pattern type 1: Linear and circular depressions in. unsorted outwash Pattern type 2: Polygonal troughs formed in unsorted outwash Pattern type 3: Sorted circles or centers of fines Pattern type 4: Mounds and depressions of low relief in fine-grained unsorted outwash Engineering applications References Appendix A: Associated studies Appendix B : Recommendations for further field and laboratory work Appendix C: Recommendations for field and laboratory techniques
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  • 16
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    Theory of densification of dry snow on high polar glaciers, II (1962)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-202-108
    In: Research report / Cold Regions Research and Engineering Laboratory, 108
    Description / Table of Contents: Summary: The theory of snow densification is further developed on the basis of an exponential relation between viscosity and density. A linear relation between load-stress and strain rate is not valid for high stresses, and is replaced by a hyperbolic sine function. An empirical function is given for the temperature cycle correction. Two equations are derived for calculating depth-density curves with computers, and a simplified one for use with desk calculators. Instructions are given for determination of function parameters from field data. Four depth-density curves for Greenland and Antarctic locations are computed and graphed to show that the theory is useful.
    Type of Medium: Series available for loan
    Pages: iv, 18, A3, B5 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 108
    URL: https://hdl.handle.net/11681/5846
    Language: English
    Note: CONTENTS Preface Summary Introduction Notation Stress analysis Analysis of densification process Non-Newtonian densification Equation for hyperbolic sine densification law Determination of parameters Discussion Glaciological engineering aspects References Appendix A: Example of calculation Appendix B: Snow density profiles
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  • 17
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    Vertical migration of particles in front of a moving freezing plane (1963)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-202-105
    In: Research report / Cold Regions Research and Engineering Laboratory, 105
    Description / Table of Contents: Summary: A principle of particle segregation by freezing is presented. It is demonstrated experimentally by using a transparent freezing cabinet in which a sample of distilled water freezes from the bottom upward. In this way the freezing front line travels vertically and the particles are carried against gravity. By using the same material with different shapes (glass beads and broken quartz or glass) it is demonstrated that an important factor in particle migration is the shape of the particle or its contact area with the interface. By testing other materials with different shapes and sizes, it is demonstrated that another important factor is particle size and rate of freezing. Fine particles migrate under a wide range of rates of freezing; coarser ones migrate at lower and more limited ranges of rates of freezing. It is suggested that, for determining frost behavior of soils in permafrost regions, freezing from the bottom upward is a more reliable test than freezing from the top down. Freezing from the bottom more closely approximates freezing of the active layer above permafrost; also, friction with the cylinder testing wall is eliminated. The implication of this principle in engineering and studies of soil genesis in cold regions is emphasized.
    Type of Medium: Series available for loan
    Pages: iv, 8 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 105
    URL: https://hdl.handle.net/11681/5848
    Language: English
    Note: CONTENTS Preface Summary Introduction Experimental procedure Experimental results Conclusions and recommendations References
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  • 18
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    Continuity in foundation models and related problems (1965)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-202-109
    In: Research report / Cold Regions Research and Engineering Laboratory, 109
    Description / Table of Contents: Summary: The present paper contains a critical study of a number of foundation models suggested by various investigators, as well as a further development of some of the ideas involved. It is found that the model by Pasternak is the most natural extension of the Winkler foundation. It is also shown that the "non-solvability" of the problem of a finite bean or plate resting on a continuous foundation as posed by Wieghardt and further elaborated by Pflanz is not correct, and that problems of this type are solvable for any load distribution permissible in classical plate theory. The paper concludes with derivations of differential equations for plates resting on viscous and viscoelastic foundations, which may be used for solving problems involving compacted snow and permafrost bases.
    Type of Medium: Series available for loan
    Pages: iv, 15 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 109
    URL: https://hdl.handle.net/11681/5834
    Language: English
    Note: CONTENTS Preface Summary Introduction The Hetényi foundation The Filonenko-Borodich foundation The Pasternak foundation Plates on a Pasternak foundation Visco-elastic Pasternak foundation Plates on visco-elastic foundations References Appendix A: Notation
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  • 19
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    Formation of lake ice in a temperate climate (1963)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-202-107
    In: Research report / Cold Regions Research and Engineering Laboratory, 107
    Description / Table of Contents: Summary: The formation of lake ice was studied during the winter of 1956-57 at Post Pond, Lyme, N. H. Tabular, columnar, granular, and crenulate textures of 36 blocks of ice observed are discussed in terms of relative growth velocity and shown in a classification chart. Ice structures are characterized by Forel striations, Tyndall figures, bubbles and strain shadows. Average crystal areas increased with ice thickness, the rate of increase being greater toward lake center, and ceased to enlarge when in a continuous bubble layer. The lake-ice sheet grew both from top and bottom, .downward growth resulting from crystals in a favorable vertical orientation of a-axes and upward growth coming about by water flowing on the original upper ice surface and freezing. Exception to this type of growth was found in the lake area which froze first, where individual crystal areas were larger at the surface and there was no upper surface ice accretion. Fabric diagrams of ice outside the anomolous area show a change of optic axis orientation from a high percentage of c-axes vertical near the surface to a high percentage horizontal at the bottom.
    Type of Medium: Series available for loan
    Pages: iv, 22, A2, B1 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 107
    URL: https://hdl.handle.net/11681/5847
    Language: English
    Note: CONTENTS Preface Summary Description of the lake Cli rna te of the lake Methods of study Ice textures Crystal size Ice structures Crystal fabric studies Growth of an ice sheet References Appendix A: Weather data Appendix B: Sample data
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  • 20
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    Mechanics of cutting and boring; Part 7: dynamics and energetics of axial rotation machines (1981)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-81/26
    In: CRREL Report, 81-26
    In: Mechanics of cutting and boring, Part 7
    Description / Table of Contents: Abstract: This report deals with force, torque, energy and power in machines such as drills and boring devices, where the cutting head rotates about a central axis while penetrating parallel to that axis. Starting from a cosideration of the forces developed on individual cutting tools, or segments of cutters, the thrust and torque on a complete cutting head is assessed, and simple relationships between thrust and torque are derived. Similarly, the energy and power needed to drive the cutting head arc estimated and related to tool characteristics. Design characteristics of existing machines are compiled and analyzed to give indications of thrust, torque, power, effective tool forces, nominal thrust pressure, power density, and specific energy.
    Type of Medium: Series available for loan
    Pages: iv, 38 Seiten , Illustrationen
    Series Statement: CRREL Report 81-26
    URL: https://hdl.handle.net/11681/9342
    Language: English
    Note: CONTENTS Abstract Preface Foreword Introduction Terminology Tool forces Parallel motion tools Indentation tools Head thrust, thrust per unit width, and nominal head pressure Power and power density Torque Specific energy Efficiency and performance index Power requirements for clearance of cuttings Minimum power requirements for lifting cuttings in a vertical hole Power consumption and efficiency in continuous-flight augers Air circulation Mud circulation Literature cited Appendix A: Vertical conveyance by continuous-fiight augers Appendix B: Surface areas on a helical flight and its stem
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