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1
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Hanover, NH : CRREL
Call number: ZSP-202-296
In: Research report
Description / Table of Contents: A theory is developed to describe the percolation of water through isothermal snow with a vertical porosity gradient. While the necessary laboratory experiments have not been done for snow, concepts from the general theory of two phase flow through porous media are used in the development. The general solution for the one-dimensional problem is given, which, when combined with any periodic boundary condition, can be used to make quantitative predictions. The theory is applied to water percolation through firn on the upper Seward Glacier (Sharp, 1951a). Using appropriate values for the parameters, theory shows a wave of volume flux which travels down into the firn and develops features similar to those observed by Sharp. These include an initially symmetric wave which distorts with depth, continuous (rather than intermittent) downward flow beneath the surface, and a decreasing value for the wave crest with depth. The rate at which the waves propagate is calculated using the method of characteristics and is in fair agreement with the observed rate where the permeability of the bulk firn with ice layers is reduced by a factor of two over homogeneous snow samples studied in the laboratory (Kuroiwa, 1963). The theory predicts that the waves advance with a shock front which grows with depth. The shock front is thought to be only an approximation to the actual physical process
Description / Table of Contents: CONTENTS: Preface. - Symbols. - Introduction. - Theory. - Darcy's Law. - Functional permeability. - Equations. - Characteristics. - Seward Glacier firn. - Discussion. - Summary. - Literature cited. - Abstract.
Type of Medium: Series available for loan
Pages: iv, 17 Seiten , Illustrationen
Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 296
Language: English
Branch Library: AWI Library
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  • 2
    Series available for loan
    Series available for loan
    Hanover, NH : Corps of Engineers, U.S. Army, Cold Regions Research and Engineering Laboratory
    Call number: ZSP-202-294
    In: Research report
    Description / Table of Contents: CONTENTS: Introduction. - Test materials. - Testing programs. - Test equipment. - Loading machine. - Environmental chamber. - Platen arrangements. - Stress/strain measurements. - Test procedures. - General. - Uniaxial compressive strength. - Diametral compression tests. - Stress/strain tests. - Test results. - Uniaxial compressive strength. - Brazil tensile strength. - Ring tensile strength. - Stress/strain characteristics. - Discussion. - Strength as a function of water content at room temperature. - Strength as a function of water content at -25°C. - Effect of temperature on the strength of nominally dry rocks. - Effect of low temperature on the strength of water-saturated rocks. - Effect of water on deformability at room temperature. - Deformability of air-dry rock as a function of temperature. - Effect of low temperature on the deformability of water-saturated rocks. - Conclusions and recommendations. - Literature cited. - Appendix A.Test materials for low temperature studies in rock mechanics. - Abstract.
    Description / Table of Contents: Strength tests were made on three types of rock, both "air-dry" and water-saturated, at temperatures from +25° to -195°C, and stress/strain tests were made down to -60°C. Strength of air-dry specimens increased with decreasing temperature at an average rate of approximately 2 x 10^-3 °C^-1, and quasi-elastic moduli increased at comparable rates. Static fatigue mechanisms in air-dry rock were apparently influenced by temperature-modification of adsorbed water. Strength of water-saturated specimens increased dramatically as pore water froze, and continued to increase down to -120°C, where compressive and tensile strengths were greater than room temperature values by factors of 5, 4 and 2 for sandstone, limestone and granite respectively. Compressive stress/strain curves for saturated rocks became steeper after freezing, and initial tangent moduli for saturated high porosity rocks increased by well over an order of magnitude.
    Type of Medium: Series available for loan
    Pages: v, 75 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 294
    Language: English
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  • 3
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    Hanover, NH : Corps of Engineers, U.S. Army, Cold Regions Research and Engineering Laboratory
    Call number: ZSP-202-292
    In: Research report
    Description / Table of Contents: CONTENTS: Preface. - General introduction. - A. Pore water freezing data from differential thermal analysis. - Apparatus and technique. - Results. - Discussion. - Conclusions. - B. Indirect determination of pore water freezing data for rocks. - Air penetration tests. - Mercury penetration measurements. - Calculation of unfrozen water content and freezing point depression. - Comparison of calculated and measured freezing characteristics. - Conclusions. - C. Electrical conductivity measurements. - Procedures. - Results. - Discussion of results. - D. Thermal strains in cold rock. - Preliminary tests. - Recording dilatometer. - Test procedure. - Results. - Discussion. - Conclusions. - E. lsothermal compressibility of cold rocks. - Test method. - Test results. - Discussion of results. - Conclusion and recommendations. - General summary of results. - Literature cited. - Appendix A: Water adsorption. - Appendix B: Adsorption and absorption by Rochester shale. - Appendix C: Low temperature conductivity of saturated wood. - Abstract.
    Description / Table of Contents: The phase composition of pore water in three types of rock subjected to temperature below 0°C was explored by a variety of techniques. Freezing point depression was measured as a function of water content by differential thermal analysis, the results yielding relationships between unfrozen water content and temperature. In an effort to avoid the practical difficulties involved in differential thermal analysis, attempts were made to determine freezing characteristics indirectly by air penetration and mercury penetration techniques applied at ordinary room temperatures. Electrical conductivity measurements were made as a function of temperature down to -195° C in an attempt to obtain information on characteristics of interfacial water films at low temperatures. Thermal strain was measured as a function of temperature in order to detect direct mechanical effects associated with phase changes, chiefly strain discontinuities brought about by volume changes in the pore water during rapid freezing and thawing. Finally, isothermal compressibility measurements, with pressures up to 27 kb, were made at - 10°C so as to determine whether the rock underwent step changes in volumetric strain at pressures corresponding to those of the phase boundaries for ice polymorphs.
    Type of Medium: Series available for loan
    Pages: v, 61 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 292
    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
    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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  • 5
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    Series available for loan
    Hanover, NH : Corps of Engineers, U.S. Army Cold Regions Research and Engineering Laboratory
    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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  • 6
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    Hanover, NH : Corps of Engineers, U.S. Army Cold Regions Research and Engineering Laboratory
    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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  • 7
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    Hanover, NH : Corps of Engineers, U.S. Army Cold Regions Research and Engineering Laboratory
    Call number: ZSP-202-343
    In: Research report
    Description / Table of Contents: CONTENTS: Abstract. - Preface. - Introduction. - Experimental procedure. - Experimental and theoretical equations. - Results and discussion. - Conclusions. - Literature cited.
    Description / Table of Contents: Simultaneous laser extinction measurements were made in warm fog at wavelengths of 0.6238, 1.15 and 10.6 [Mu]. The warm fog was generated in a 4-m^3 environmental chamber. Particle sampling was carried out simultaneously with the laser measurements using an impactor. Using the same size distribution in each case the theoretical extinction coefficients were calculated and compared with the experimental coefficients. Results obtained during this experiment and aprevious one indicate that propagation at 1.15 [Mu] is adversely affected by the presence of atmospheric water vapor. Experimental data obtained simultaneously at 0.6328 and 10.6 [Mu] indicate that virtually no difference exists between the extinction coefficients at these two wavelengths for moderate particle concentrations while at much larger concentrations [Alpha]0.6328 increases indefinitely while [Alpha]10.6 levels off at 0.2.
    Type of Medium: Series available for loan
    Pages: iii, 7 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 343
    Language: English
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  • 8
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    Series available for loan
    Hanover, NH : Corps of Engineers, U.S. Army Cold Regions Research and Engineering Laboratory
    Call number: ZSP-202-342
    In: Research report / Cold Regions Research and Engineering Laboratory
    Description / Table of Contents: CONTENTS: Abstract. - Preface. - Introduction. - Experimental procedure. - Results. - Work-hardening effect. - Strain rate sensitivity of flow stress. - Discussion. - Conclusions. - Literature cited.
    Description / Table of Contents: Single crystals of high purity ice deformed by uniaxial compression on an Instron machine showed remarkable work-hardening after about 8% strain. By changing the strain rate during compression tests in the plastic region of the stress-strain curve, an apparent activation volume V* and a dislocation mobility exponent m were calculated from the strain rate sensitivity of flow stress. The large work-hardening and the rapid increase in the value of m beyond about 10% strain indicate that the plastic flow in this region is controlled by dislocation intersections and nonconservative motion of jogs.
    Type of Medium: Series available for loan
    Pages: iii, 11 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 342
    Language: English
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  • 9
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    Hanover, N.H. : U.S. Army Cold Regions Research and Engineering Laboratory
    Call number: ZSP-202-349
    In: Research report / Cold Regions Research and Engineering Laboratory, 349
    Description / Table of Contents: CONTENTS: Abstract. - Preface. - Introduction. - Test locations. - Post Pond. - Mascoma Lake. - Winter freeze-up. - Ice cover properties. - Stratigraphy. - Microstructure. - Porosity. - Impurity content. - Flexural strength. - Test sites. - Beam test procedure. - Beam dimensions. - Beam temperatures. - Beam strengths. - Results. - Post Pond, Site PB, 12 February 1974. - Post Pond, Site PC, 21 February 1974. - Mascoma Lake, Site MD, 25 February 1974. - Mascoma Lake, Site MD, 26 February 1974. - Mascoma Lake, Site MD, 1 March 1974. - Post Pond, Site PA, 4 March 1974. - Post Pond, Site PA, 7 March 1974. - Post Pond, Site PA, 8 March 1974. - Post Pond, Site PB, 12 March 1974. - Post Pond, Midway between Sites PB and PC, 15 March 1974. - Post Pond, Midway between Sites PA and PB, 26 March 1974. - Post Pond, Midway between Sites PA and PB, 29 March 1974. - Post Pond, Midway between Sites PA and PB, 3 April 1974. - Conclusions. - Literature cited.
    Description / Table of Contents: In-place cantilever beam tests on Post Pond and Mascoma Lake ice yielded a maximum flexural strength of 7.1 kg/cm^2. The minimum strength, unrelated to failure along pre-existing cracks in the ice, was 2.9 kg/cm^2. The majority of tests were performed in the push-down mode after it was discovered that beams tested in the pull-up mode, which places the bottom surface in tension, frequently broke prematurely along cracks in the bottom of the ice. Premature failures of this kind usually occurred at stresses of 2-3 kg/cm^2. Data further demonstrate that the intrinsic strength of lake ice decreases significantly as the surface air temperature goes to 0°C. Ice that has just become isothermal, but has not yet begun to candle, has a strength of about 4 kg/cm^2; ice that has been subjected to prolonged periods of above-freezing air temperatures generally fails at about 3 kg/cm^2. Tests also show that cold unrecrystallized snow-ice is as strong as the underlying lake ice. Tests of the effect of crystalline structure indicate that ice composed of crystals with their c-axes horizontal is measurably stronger than ice in which the crystals are oriented with their c-axes vertical.
    Type of Medium: Series available for loan
    Pages: v, 28 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 349
    Language: English
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  • 10
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    Hanover, N.H. : Corps of Engineers, U.S. Army Cold Regions Research and Engineering Laboratory
    Call number: ZSP-202-297
    In: Research report
    Description / Table of Contents: CONTENTS: Preface. - Abstract. - Introduction. - Glenn Creek watershed. - Location. - Topography. - Geology, soils and permafrost. - Climate. - Vegetation. - Data collection. - Precipitation. - Stream flow. - Air temperature and relative humidity. - Water temperature. - Evaporation. - Snow surveys. - Depth of thaw. - Dissolved solids. - Hydrology. - Introduction. - General channel description. - Hydraulic geometry. - Characteristics of hydrographs. - Sources of streamflow. - Attempts at flow separation. - Hydrograph modeling. - Summary and conclusions. - Literature cited. - Appendix A: Summary of permafrost probe observations, Glenn Creek watershed.. - Appendix B: Water-holding and-transmitting properties of moss. - Appendix C: Summary of hydraulic geometry data from 1964 discharge measurements. - Appendix D: Summary of data used in computing recession constants.
    Description / Table of Contents: The results of a four-summer (1964-1967) hydrologic study of the watershed of Glenn Creek, about 8 miles north of Fairbanks, Alaska, in the Yukon-Tanana uplands physiographic province, are presented. This work was initiated to provide initial baseline hydrologic data for a small subar ctic watershed, the first of its kind in North America. Standard hydrologic and meteorologic instrumentation was used, and streamflow characteristics were analyzed by standard hydrograph-analysis techniques. The stream is second-order, and drains an area of 0.70 square mile. Basin elevations are from 842 ft to 1618 ft. In regard to topography, geology, soils, permafrost, vegetation, and climate, the watershed seems to be representative of low-order, low-elevation drainage basins in the province. Analysis of rainfall-runoff data indicates that about half the 12.3-in. normal annual precipitation is runoff. The remainder is the actual evapotranspiration , which equals only about 30% of estimated potential evapotranspiration. For individual storms, runoff/rainfall proportions were from 0.03 to 0.42 and were positively correlated with antecedent discharge of the stream, which is a measure of watershed wetness. The stream responds rapidly to rainstorms except when the basin is very dry, and has markedly slow recessions compared with temperate region streams of similar size. Rate of recessions is apparentlv controlled by concurrent evapotranspiration rates. Analysis of hydrographs and knowledge of the physical characteristics of the basin indicate that storm runoff occurs initially as surface runoff from bare soil areas adjacent to the stream, while recessions are dominated by a combination of tunnel flow beneath moss-covered parts of the basins and typical groundwater flow through the moss and soils. Peak discharges for individual storms could be well estimated by an equation including antecedent discharge, total precipitation and storm duration, and average recession constant. These results represent the first detailed hydrologic data from the discontinuous permafrost zone of the North American taiga and should be of significance to the International Hydrological Decade and International Biological Program.
    Type of Medium: Series available for loan
    Pages: vi, 111 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 297
    Language: English
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