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  • Hanover, NH : Corps of Engineers, U.S. Army Cold Regions Research and Engineering Laboratory  (22)
  • English  (22)
  • Norwegian
  • 1970-1974  (22)
  • 1950-1954
  • 1
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    Hanover, NH : Corps of Engineers, U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-202-281
    In: Research report
    Description / Table of Contents: The solution for the vibration of an elastic plate floating on water is developed. The water is assumed to be incompressible and to have irrotational flow. In free vibration upon release of the plate, the maximum negative rebound of the deflection is 25%. For forced vibration, the steady state part of the solution shows that there is a frequency at which the deflection is a maximum. The stresses become a maximum at a frequency higher than the one for deflection. These critical frequencies depend upon the plate's characteristic length and the depth of the water. For most situations the critical frequency for stress is less than 0.2 cycle per second. At this critical frequency the stresses are amplified over the static case by a factor less than 10%.
    Type of Medium: Series available for loan
    Pages: ii, 9 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 281
    Language: English
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  • 2
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    Hanover, NH : Corps of Engineers, U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-202-243
    In: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command, 243
    Description / Table of Contents: The internal friction of single-crystal ice has been attributed to reorientation of the water molecule under periodic stress. However, the theory for damped dislocations, which offers another mechanism for the internal friction of ice, has not been investigated. The effects of scratching the surface of 41 ice samples and X-irradiating and plastically deforming them were evaluated. The effects observed on the internal friction of pure, single-crystal ice, in the flexure mode of oscillation between 400 and 1400 Hz, supported the existence of a dislocation-controlled mechanism, with the drag produced by the interaction of the dislocation with the protons in the crystal. In addition, analysis of the detailed shape of the data curve showed two peaks of tan delta as a function of temperature. The second peak, which had not been previously reported, had an activation energy of 0.16 eV and a relaxation time of 1.7 x 10^8 sec at infinite temperature. These experiments indicated that both peaks vrere controlled by the dislocation mechanism described above.
    Type of Medium: Series available for loan
    Pages: iv, 41 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 243
    Language: English
    Note: CONTENTS: Introduction. - Previous work. - Previous theory. - Internal friction of a crystal. - Granato-Lücke theory of dislocation damping. - Double kink mechanism. - Mechanisms not involving dislocations. - Experimental work. - Experimental approach. - Experimental apparatus. - Mode of oscillation. - Automated system. - Support, acoustic isolation, and temperature control. - Sample preparation. - X-ray apparatus. - Data analysis. - Stage I. - Stage II. - Stage III. - Experimental results and discussion. - The second peak. - Interpretation of scratching, X-irradiation, and plastic deformation. - Scratching. - X-irradiation. - Plastic deformation. - Supporting research. - Interpretation of the two peaks. - Conclusions. - Literature cited. - Appendix A: Computer programs. - Abstract.
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  • 3
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    Hanover, NH : Corps of Engineers, U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-202-274
    In: Research report
    Description / Table of Contents: CONTENTS: Introduction. - The ice/ice interface. - The ice/air interface. - The silicate/water/silicate interface. - The silicate/water/ice interface. - Summary. - Literature cited. - Abstract.
    Description / Table of Contents: Interfacial regions in frozen soils are of the following types: ice/ice (grain boundary) ice/water/air, silicate/water/silicate (interlamellar) and silicate/water /ice (extralamellar). For the last, the mid-portion of the interfacial region should be regarded as a liquid-like solution of the ionic and undissociated substances sorbed by the interface and expelled from the ice during freezing. The interfacial forces operative in these regions result in distinct differences in the properties and behavior of the interfacial water, compared with water in bulk; but, in spite of strong interfacial forces, the interfacial water exhibits liquid-like mobility in its response to many kinds of driving forces. From the evidence and arguments considered, it is concluded that distinctly different zones of orientational order can be distinguished within the interfacial regions. For an advancing silicate/water/ice interface it is proposed that there is a zone of strong perturbation and disorder immediately proximate to silicate surfaces in which the protons of water molecules are partially delocalized; this makes them more easily dissociated. Two or three molecular diameters removed from the silicate surface the interfacial forces operative there combine to create a zone of enhanced order in the molecular configurations. At some farther distance, depending upon the temperature below freezing, it is suggested that there exists a disordered transition zone proximate to the ice surface as portrayed in Drost-Hansen's model. It is suggested that future investigations will contribute refinements in the model and will uncover still further complexities in the various interfaces mentioned.
    Type of Medium: Series available for loan
    Pages: iii, 19 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 274
    Language: English
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  • 4
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    Hanover, NH : Corps of Engineers, U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-202-302
    In: Research report
    Description / Table of Contents: CONTENTS: Introduction. - Literature review. - Experimental procedure. - Experimental and theoretical equations. - Results and discussion. - Conclusions. - Literature cited. - Appendix A. Some problems in the experimental determination of the extinction coefficient of ice fog. - Appendix B. Ice fog production technique. - Appendix C. Ice fog samples and their corresponding particle spectra. - Abstract.
    Description / Table of Contents: Laser extinction measurements in ice fog were made at wavelengths of 0.6328, 1.15 and 3.39 microns. The ice fog was generated in an environmental chamber whose temperature could be lowered to -43°C. Particle sampling was carried out simultaneously with the laser measurements using an impactor. Size distributions were derived from the impactor measurements. These data were used to compute Mie extinction coefficients at the three laser wavelengths. These coefficients were compared with the coefficients derived experimentally. Although some discrepancy exists between theory and experiment, both agree fairly well on the behavior of the extinction coefficient as a function of particle concentration.
    Type of Medium: Series available for loan
    Pages: iii, 23 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 302
    Language: English
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  • 5
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    Hanover, NH : Corps of Engineers, U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-202-287
    In: Research report
    Description / Table of Contents: Hugoniot curves were generated from simultaneous measurements of shock and free-surface velocities, obtained from samples of frozen Fairbanks (Fox) silt, using the exploding wire technique. The abrupt change in slope of the Us-Up Hugoniot is indicative of a phase change. The shape of the P-V Hugoniot suggests that the transformation begins immediately but does not go to completion. This means that, although the pressure lies slightly above the Rayleigh line through the mixed phase region, the slope does not increase as rapidly as it would if the material had stayed in the initial phase.
    Description / Table of Contents: CONTENTS: Preface. - Conversion factors. - Introduction. - Test procedure. - Test results. - Discussion. - Literature cited. - Appendix A: Hugoniot data. - Abstract.
    Type of Medium: Series available for loan
    Pages: iv, 13 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 287
    Language: English
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  • 6
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    Hanover, NH : Corps of Engineers, U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-202-286
    In: Research report
    Description / Table of Contents: CONTENTS : Introduction. - Basic analysis. - Part I: Far field surface motion. - A single oscillating source. - A group of forces over a finite area. - Part II: Near field study. - Motion at center of source. - Approximation of displacements. - Conclusion. - Literature cited. - Abstract.
    Description / Table of Contents: Wave propagation generated by vibratory load on a homogeneous, isotropic, linear viscoelastic half-space is studied. The effect of a single concentrated force and a group of forces applied over a circular area has been examined and solutions of the displacement functions are presented. In the case of the group forces, the three types of force distribution used by Reissner and Sung were employed. At a great distance (far field) from the applied load, surface displacements are reduced to closed form expressions. A field method based on these results is recommended for determining the complex modulus and the damping property of a viscoelastic material. For areas near the source (near field), numerical procedures were employed to evaluate the integral solution. To facilitate the application, two simplified versions are provided for calculating the center displacement under the load. They both provide good approximation to the integral solution and, most important of all, they speed up the computation enormously
    Type of Medium: Series available for loan
    Pages: iv, 33 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 286
    Language: English
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  • 7
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    Hanover, NH : Corps of Engineers, U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-202-317
    In: Research report
    Description / Table of Contents: Experiments by Smith-Johannsen on the adhesion of ice frozen from a number of 1 x 10^-3 ? electrolyte solutions to a wax-treated aluminum surface at -10°C are discussed. It is concluded that the adhesive strength measured by the force per square centimeter needed to shear the ice off the substrate surface is mainly due to a liquid interfacial solution layer between the ice and the substrate surface. The thickness of such a layer is largely determined by the same considerations as the thickness of grain boundary layers in ice obtained from dilute electrolyte solutions.
    Type of Medium: Series available for loan
    Pages: ii, 9 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 317
    Language: English
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  • 8
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    Hanover, NH : Corps of Engineers, U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-202-307
    In: Research report
    Description / Table of Contents: CONTENTS: Introduction. - Part 1.The concept of isotropy clarified by the introduction of non-coaxial mechanics. - Part 2. Systematization of the theory of plasticity with indefinite angle of non-coaxiality. - Analysis of stress. - Analysis of strain-rate. - Principle of partial coincidence. - Strain-rate characteristic directions. - Equations for practical use. - Conclusion. - Literature cited. - Appendix A.The sense of the [Sigma],[Gamma] coordinate system. - Appendix B. Another derivation of the equations of velocity components. - Appendix C. Equations of velocity components in stress characteristic directions.
    Description / Table of Contents: One of the difficulties that have hampered the development of the mathematical theory of soil plasticity was recently overcome by Mandl and Luque. They showed that the non-coaxiality of the principal axes of a stress tensor and a strain-rate tensor can occur only in plane deformation. Their assumption that the angle of non-coaxiality should be a material constant cannot be supported, however. The angle of noncoaxiality should be determined so that the solution to the given problem can exist. It is demonstrated in one of the examples in this paper that a well-known solution in which the angle of non-coaxiality is assumed to be zero does violate the assumed boundary condition. The theory was reorganized bv using new insights given by Mandl and Luque. It is concluded that still missing is one condition that enables us to determine the angle of non-coaxiality as a function of space.
    Type of Medium: Series available for loan
    Pages: iii, 31 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 307
    Language: English
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  • 9
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    Hanover, NH : Corps of Engineers, U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-202-303
    In: Research report
    Description / Table of Contents: CONTENTS: Preface. - Notation. - 1.Introduction. - 1.1Definition and scope of problem. - 1.2 Theoretical background. - 1.3 Previous work on the single plate-grouser problem. - 1.4 Background of the present investigation. - 2.Theory of two-dimensional soil failure by a plate-grouser. - 2.1 Basic criteria and assumptions. - 2.2 Rupture zones and boundaries. - 2.3 Forces in the spiral and Rankine zones. - 2.4 Solution to forces of the equilibrium wedge abc when [Theta]c 〉 [Theta] 〉 (- [Epsilon] [equal to or greater] -[Beta]). - 2.5 Solution to the forces H and V. - 3. Observation of soil rupture patterns. - 3.1 General. - 3.2 Test equipment and photographic technique. - 3.3 Photographing failure patterns. - 3.4 Observation of the equilibrium wedge when [Theta]c 〉 [Theta] 〉 - [Epsilon]. - 3.5 Rupture patterns at [Theta] = 90°. - 4. Force measurements. - 4.1Test program. - 4.2 The plate-grouser test apparatus. - 4.3 The measurement of soil strength. - 4.4 Results of controlled [Theta] tests. - 5. Conclusions. - Literature cited. - Appendix A: Details of mathematical methods. - Appendix B: Computer program. - Appendix C: Examples of application. - Appendix D: Photographs of failure patterns. - Abstract.
    Description / Table of Contents: The most common example of the application of inclined loads to the soil is the plate-grouser. This consists of a strip footing with a vertical arm at one end. The most usual loading arrangement is one in which a fixed vertical load is applied and then the horizontal load is increased until failure occurs. A theory has been developed which will predict the maximum horizontal force, assuming that the soil is dense enough to be reasonably described by the Coulomb equation. The theory is based on slip line fields including wedges of soil that are not failing. These slip line fields vary systematically with the interface angle [Beta] and the angle of internal shearing resistance of the soil [Phi] and they are a function of the direction of motion of the interface [Theta]. A computer program is provided which will solve the problem directly if the direction of motion [Theta] is given. It will also solve the more practical situation described above by an iterative procedure. The postulated slip line fields have been shown to be correct by means of glass box photographs giving excellent agreement with the theory. The predictions of passive pressure have been verified by a series of force measurements on quite large grousers driven into saturated clay, dry sand and an intermediate loam.
    Type of Medium: Series available for loan
    Pages: vi, 93 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 303
    Language: English
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  • 10
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    Hanover, NH : Corps of Engineers, U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-202-300
    In: Research report
    Description / Table of Contents: CONTENTS: Introduction. - Sampling. - Byrd Station. - Plateau Station. - Camp Century. - lnge Lehmann. - Grain-crystal relations. - Analytical techniques. - Thin sections. - Crystal size measurements. - Results and discussion. - Literature cited. - Appendix A: Crystal size as a function of depth and age in the Antarctic and Greenland ice sheets. - Abstract.
    Description / Table of Contents: The growth of ice crystals as a function of depth and time in polar firn and glacier ice has been investigated at a number of locations in Antarctica and Greenland. Thin sections of snow and ice were used to measure crystal size variations which showed, in all cases, that crystal size increases essentially linearly with the age of samples. Crystal growth rates are strongly temperature dependent. At Camp Century, Greenland, where the firn temperature is -24°C, crystals grow approximately 23 times faster than at Plateau Station, Antarctica, where the in situ temperature is -57°C. Extrapolation of the existing data indicates that crystal growth rates in polar firn and ice could be expected to vary by about two orders of magnitude over the temperature range -60°C to -15°C. Examination of the changes in the pore-crystal structure relationships to a dpeth of 100 m at Camp Century shows that these changes closely resemble those occuring in the full-scale isothermal sintering of powder compacts.
    Type of Medium: Series available for loan
    Pages: iii, 19 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 300
    Language: English
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