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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-201-84/33
    In: CRREL Report, 84-33
    Description / Table of Contents: A small-scale experimental study was conducted to characterize the magnitude and nature of ice forces during continuous crushing of ice against a rigid, vertical, cylindrical structure. The diameter of the structure was varied from 50 to 500 mm, the relative velocity from 10 to 210 mm/s, and the ice thickness from 50 to 80 mm. The ice tended to fail repetitively, with the frequency of failure termed the characteristic frequency. The characteristic frequency varied linearly with velocity and to a small extent with structure diameter. The size of the damage zone was 10 to 50% of the ice thickness, with an average value of 30%. The maximum and mean normalized ice forces were strongly dependent on the aspect ratio (structure diameter/ice thickness). The forces increased significantly with decreasing aspect ratio, but were constant for large aspect ratios. The maximum normalized forces appeared to be independent of strain rate. The effect of velocity on the normalized ice forces depended on structure diameter. The mean effective pressure or specific energy of ice crushing depended on both aspect ratio and ice-structure relative velocity. The energy required to crush the ice for the one failure cycle was obtained from the ice force records for each test, and was compared to the energy calculated from an idealized sawtooth shape for the force record, the maximum force, velocity and characteristic frequency data. Originator - supplied keywords included: Cold regions, Cold regions construction, Cylindrical test structures, Ice, Ice crushing, Ice forces, and Test facilities.
    Type of Medium: Series available for loan
    Pages: vi, 47 Seiten , Illustrationen
    Series Statement: CRREL Report 84-33
    Language: English
    Note: Contents Abstract Preface Nomenclature Introduction Test objectives Experimental setup and procedures Facilities Test fixture Data acquisiton system Ice sheets Measurement of ice properties Daily test summary Experimental results and discussion Observations Ice force records Frequency of ice force variations Discussion Maximum crushing forces Mean effective pressure or specific energy of ice in crushing Failure energy of ice Ratio of maximum force to mean force Summary and conclusions Literature cited Appendix A: Data for continuous crushing tests
    Location: AWI Archive
    Branch Library: AWI Library
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Ground water monitoring & remediation 19 (1999), S. 0 
    ISSN: 1745-6592
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences
    Notes: A dry barrier consists of a laterally continuous soil layer that is dried by air flow. Dry atmospheric air is passed through a soil layer (preferably of a coarse texture). accumulates water vapor, then emerges from the formation as moist air. Removal of soil moisture limits or prevent downward water movement. Drying a soil layer with air is possible when atmospheric air contains less water vapor than soil pore gas. The design of an effective dry barrier is highly site dependent and requires knowledge of the site geology, of the extent of the contaminant plume, and climatic conditions. Climatic conditions at the site are important in two ways: (1) the efficiency of atmospheric air in drying: soil depends on its absolute humidity: and (2) the amount of infiltration from precipitation influences how much water has to be removed from the soil to maintain a dry barrier. The size of the barrier, combined with the climatic conditions, determines the air flow required to maintain the system. while the hydraulic characteristics of the soils determine the location and design of air injection and extraction wells. The electric power rate structure must be known to calculate operating costs. The principal factors which determine the feasibility of a dry barrier include: (1) the climate at the site and, most importantly, low-absolute atmospheric humidity during much of the year; (2) a substantial unsaturated zone; and (3) the ability to circulate air through the unsaturated zone. The amount of initial soil moisture in the layer through which air is circulated may be an important factor in the feasibility of a dry barrier. A design study is presented that illustrates the trade-offs between high capital costs of constructing a large number of air circulation wells vs. the high operating costs required to pump large volume of air over long distances through fewer wells. This study found that, under conditions similar to those in many arid regions, a dry barrier may be a technically and economically viable method of providing temporary waste containment.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Geotechnical and geological engineering 16 (1998), S. 201-213 
    ISSN: 1573-1529
    Keywords: capillary barrier ; surface cover ; unsaturated flow ; numerical simulation ; numerical model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract This paper presents a comparison of numerical simulations to the measured response of capillary barrier field tests. The simulations were of pilot-scale tests of four 7 m long, 1.2 m thick capillary barriers, two with 5% slopes and two with 10% slopes, with and without an included unsaturated drainage layers. The unsaturated drainage layer was included to encourage lateral drainage. The 5% sloped barriers were subjected to a period of constant infiltration for a period of 74 days, while the 10% system with the drainage layer had water added for 26 days and the conventional capillary barrier with a 10% slope was subjected to 43 days of infiltration. The numerical modelling was conducted using both drying and wetting soil moisture characteristic curves to determine their influence on the results. Differences between the field test and the model data were found, but in general the simulations appeared to adequately reproduce the response of the test systems. It was found that the use of wetting curve data provided a better fit to the field data, more accurately predicting the amount and timing of the percolate produced. © Rapid Science Ltd. 1998
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Transport in porous media 36 (1999), S. 23-42 
    ISSN: 1573-1634
    Keywords: moisture removal ; drying ; two-layer porous media ; mass transfer ; conceptual model ; dry barrier.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract Moisture removal from a two-layer porous media in which air is circulated through one layer and moisture is removed from the second has not been well studied due to the emphasis given to single-layer systems. This two-layer configuration is common in natural and engineered systems and can be used as a means to create a barrier to downward migrating fluids and to remove liquids and gases that may be present in the finer layer. However, there is little data on moisture removal from a two-layer porous media in which air is circulated through one layer parallel to the interface and moisture is removed from the finer second layer by evaporation. A conceptual model of the moisture removal from a two-layer porous media system was developed and compared to experimental moisture removal rates from laboratory scale dry barriers. The limited experimental data agrees well with the results predicted by the conceptual model, providing an initial validation.
    Type of Medium: Electronic Resource
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  • 5
    Publication Date: 1998-04-01
    Print ISSN: 1090-0241
    Electronic ISSN: 1943-5606
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
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  • 6
    Publication Date: 1999-12-01
    Print ISSN: 1090-0241
    Electronic ISSN: 1943-5606
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
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  • 7
    Publication Date: 1999-10-01
    Print ISSN: 1090-0241
    Electronic ISSN: 1943-5606
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
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  • 8
    Publication Date: 1999-08-01
    Print ISSN: 1069-3629
    Electronic ISSN: 1745-6592
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences
    Published by Wiley
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