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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-202-95
    In: Research report / Cold Regions Research and Engineering Laboratory, 95
    Description / Table of Contents: Summary: An investigation was conducted at Camp Century, Greenland, to study the feasibility of using air wells to cool undersnow structures in the arctic during the summer months. From results obtained during the summers of 1959,and 1960 and late November, 1960, it was found that the air well is a practical and effective means of providing a -20°C air supply at volumetric flow rates of 1200 to 1700 ft^3/min. The extent and rate of warming of the snow beneath the trench floor by heat exchange between the air and the snow foundation was found to depend upon trench air temperature, fan capacity, fan arrangement, and casing length. For example, in a well cased to a depth of 17. 5 ft and equipped with a 5 hp fan drawing in air at a rate of 1700 ft^3/min, the maximum warming was found to be 12.5°C during a 42-day period. Snow temperature differences of about 7°C were found between similar trenches with and without a fan installation. The minimum permissible distance between two adjacent fans to eliminate, overlap in warming up the snow foundation is approximately 80 ft.
    Type of Medium: Series available for loan
    Pages: iv, 17 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 95
    Language: English
    Note: CONTENTS Preface Summary Theoretical background Test method and equipment Test operations Effectiveness of the air well Estimation of fan capacity Natural cooling in winter Change of trench foundation temperature Trench wall warm-up Conclusions and recommendations
    Location: AWI Archive
    Branch Library: AWI Library
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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-202-37
    In: Research report / Cold Regions Research and Engineering Laboratory, 37
    Description / Table of Contents: Summary: Laboratory experiments on the air permeability of various screened and natural snows are described, and, results are analyzed to determine whether the parameters obtained from the measurements could be used to define a snow type. The permeability of a snow sample of known porosity (calculated from density) was determined over a wide range of air velocities; the sample was then compacted artificially a few mm, its density was determined, and its permeability measured again. The procedure was used to obtain curves for several densities of the same sample. Air flow appeared laminar for velocities less than 5 cm/sec in fine-grained snow (less than 0.8 mm in diam.), 2 cm/sec in medium-grained snow (0.8-1.2 mm diam.), and 1 cm/sec in larger-grained snow. A formula is presented expressing all of the results obtained under laminar-flow conditions in a single relationship, and an equation for estimating grain size from initial permeability and initial porosity is suggested. Snow conversion tables and a discussion of the effect of varying sample porosity on its permeability are appended.
    Type of Medium: Series available for loan
    Pages: iv, 19, A2, B6 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 37
    Language: English
    Note: CONTENTS Page Preface Summary Introduction Apparatus and method Experimental results and discussion Historical background Range of Darcy's law Effect of porosity on the permeability of snow Bader's equation Conclusion References Appendix I. Snow conversion table: Density to absolute porosity Appendix II. Effect on permeability of varying porosity in the sample Porosity varies with length Porosity varies with cross section
    Location: AWI Archive
    Branch Library: AWI Library
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