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  • 1970-1974  (1,627)
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  • 1
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-202-314
    In: Research report
    Description / Table of Contents: CONTENTS: Introduction. - Previous work. - Sea ice terrain model. - Traffic ability model. - Analytic calculation of DT/DSL. - Monte Carlo calculation. - Results of traffic ability computations. - Experimental traffic ability ratios using ridge overlays. - Regional variations in ridging intensity. - Additional traffic ability aspects of sea ice. - Shear zone and rubble fields. - Linear lead systems. - Conclusions. - Literature cited. - Appendix A. Distribution of the lateral extent of ridges. - Abstract.
    Description / Table of Contents: A sea ice terrain model, based upon previously tested height and spacing distributions for sea ice pressure ridging, is developed. Using this model, and additional information on pressure ridge extents, a trafficability model for vehicles traversing the pack ice is developed. Both analytic and Monte Carlo calculations of vehicle trafficability, measured in terms of the average ratio of the total distance traveled over a straight-line distance, are performed. The calculations include cul-de-sacs due to ridge intersections. The trafficability ratio is given as a function of ridge-height-clearance ability of the vehicle and of ridging parameters which may be obtained from laser profiles of the arctic pack ice. Results are in good agreement with simulated routes through sea ice terrain taken from aerial photo mosaics. Contour plots of ridging parameters taken from laser profilometry are also supplied. These plots, together with the trafficability model, supply mobility information for the whole of the western portion of the Arctic Basin.
    Type of Medium: Series available for loan
    Pages: iii, 21 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 314
    Language: English
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  • 2
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-202-313
    In: Research report
    Description / Table of Contents: CONTENTS: Preface. - Nomenclature. - Introduction. - Funicular regime. - Grain growth. - Grain contacts. - Densification. - Pendular regime. - Discussion and conclusions. - Literature cited. - Abstract.
    Description / Table of Contents: Grain growth, bond growth and densification of wet snow are described in terms of the distribution of equilibrium temperature in the snow matrix. At high water saturations the equilibrium temperature increases with grain size; hence, small particles melt away as large particles grow. Melting also occurs at the intergrain bonds, causing a low strength and rapid densification. At low saturations the equilibrium temperature is determined by the capillary pressure and the particle sizes have only a second order effect. Therefore, grain growth proceeds slowly and, even at large overburden pressures, no intergrain melting occurs. At low saturations the water "tension" acts through a finite area, thus large attractive forces exist between the grains, and the strength of the snow matrix is large.
    Type of Medium: Series available for loan
    Pages: v, 13 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 313
    Language: English
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  • 3
    Series available for loan
    Series available for loan
    Hanover, NH : Corps of Engineers, U.S. Army, Cold Regions Research and Engineering Laboratory
    Associated volumes
    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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  • 4
    Series available for loan
    Series available for loan
    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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  • 5
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-202-310
    In: Research report
    Description / Table of Contents: CONTENTS: Introduction. - Field sites and procedures. - Results. - Discussion. - Conclusions. - Literature cited. - Appendix A: Tabulation of AIDJEX core data. - Appendix B: Tabulation of average salinity/ice thickness data. - Abstract.
    Description / Table of Contents: The salinity distribution in multiyear sea ice is dependent on the ice topography and cannot be adequately represented by a single average profile. The cores collected from areas beneath surface hummocks generally showed a systematic increase in salinity with depth from 0 0/00 at tne surface to about 4 0/00 at the base. The cores collected from areas beneath surface depressions were much more saline and displayed large salinity fluctuations. Salinity observations from sea ice of varying thicknesses and ages collected at various arctic and subarctic locations revealed a strong correlation between the average salinity of the ice, S, and the ice thickness, h. For salinity samples collected from cold sea ice at the end of the growth season, this relationship can be represented by two linear equations: S = 14.24 - 19.39h (h? 0.4 m) ; S = 7.88 - 1.59h (h 〉 0.4 m) . It is suggested that the pronounced break in slope at 0.4 m is due to a change in the dominant brine drainage mechanism from brine expulsion to gravity drainage. A linear regression for the data collected during the melt season gives S = 1.58 + 0.18h. An annual cyclic variation of the mean salinity probably exists for multiyear sea ice. The mean salinity should reach a maximum at the end of the growth season and a minimum at the end of the melt season.
    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 310
    Language: English
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  • 6
    Series available for loan
    Series available for loan
    Hanover, NH : Corps of Engineers, U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    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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  • 7
    Series available for loan
    Series available for loan
    Hanover, N.H. : Corps of Engineers, U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    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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  • 8
    Series available for loan
    Series available for loan
    Hanover, NH : Corps of Engineers, U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-202-311
    In: Research report
    Description / Table of Contents: CONTENTS: Preface. - Notation. - Introduction. - Review of observations. - Review of theory. - Water flow through textured layers. - Water flow past semipermeable layers. - Discussion. - Literature cited. - Abstract.
    Description / Table of Contents: The flow of water through layered snowpacks is discussed. A method for predicting flow through unsaturated layers is given. The flow along ice layers and through ice layers is analyzed in terms of the slope, permeability, thickness and length of the layers. It is shown that the permeability of ice layers required to cause large flow diversions is quite small. The effect of slope is large even at small angles.
    Type of Medium: Series available for loan
    Pages: v, 15 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 311
    Language: English
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  • 9
    Series available for loan
    Series available for loan
    Hanover, NH : Corps of Engineers, U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-202-309
    In: Research report
    Description / Table of Contents: CONTENTS: Preface. - Symbols. - Introduction. - Physical setting. - Flow model. - Calculated flow. - Existing profile. - Proposed profiles. - Profile 1. - Profile 2. - Profile 3. - Profile 4. - Profile 5. - Profile 6. - Profile 7. - Total excavation. - Interpretation and conclusions. - Sources of error. - Recommendations. - Literature cited. - Appendix A. - Abstract.
    Description / Table of Contents: The Marcona Corporation and Kryolitselskabet ?resund, A/S (a Danish corporation) are cooperatively investigating the possibility of developing an open-pit mine along the edge of the Greenland Ice Cap. The response of the glacier to a sudden change in surface slope and thickness is calculated. The existing flow is diverted away from the mineral deposit but will increase when the excavation begins. It is calculated that 66 million cubic meters of ice must be removed in order to establish a stable profile beyond the pit. An additional 7.9 million cubic meters of ice must be removed yearly in order to maintain the profile.
    Type of Medium: Series available for loan
    Pages: v, 25 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 309
    Language: English
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  • 10
    Series available for loan
    Series available for loan
    Hanover, NH : Corps of Engineers, U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-202-306
    In: Research report
    Description / Table of Contents: CONTENTS: Introduction. - 1. Coastal stations. - Alaska. - Canada. - Greenland. - Europe and Russia. - II. The interior Arctic Ocean. - Zone 1. - Zone 2.. - Zone 3. - Zone 4. - Zone 5. - Zone 6.. - Summary and discussion. - Supplemental data. - Literature cited. - Appendix A. Winds. - Appendix B. Arctic surface winds. - Appendix C. Excerpt from Cold Regions Science and Engineering, USA CRREL Monograph I-A3b. - Appendix D. Excerpt from Proceedings of the Arctic Basin Symposium October 1962. - Abstract.
    Description / Table of Contents: Prevailing monthly and seasonal surface wind directions were obtained from 1) weather records for 21 coastal stations around the Arctic Ocean and 2) a series of U.S. Navy wind charts for 15 to 20 locations in the arctic marginal seas and the ocean's interior. This information was combined and analyzed to develop 2 charts which depict the surface flow of air in these areas during the mid-summer and mid-winter months. Since the ice floe stations used in the offshore wind analysis are not permanently located, the Arctic Ocean was selectively divided into 6 zones. Three of these zones separate Polar regions north of 84°N latitude, and 3 other zones each separate the seas bordering the north coasts of Europe, Siberian Russia and North America. Except for a few stations where wind directions are apparently controlled by local influences the results showed the following mid-winter patterns: 1) a near anticlockwise flow within the circle north of 75°N, 2) winds from the north in and near the Chukchi and Bering Seas, 3) northeast winds along the Alaskan coast and northwest along the Canadian Archipelago Islands, and 4) southwest and southeast winds along the northern coasts of Europe and Asia respectively. Although the wind directions during mid-summer become more variable the study showed that the prevailing surface winds for most areas in this season are nearly opposite those observed in winter.
    Type of Medium: Series available for loan
    Pages: iii, 55 Seiten , Illustrationen, Karten
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 306
    Language: English
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