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  • 2000-2004
  • 1975-1979  (8)
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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-201-79/29
    In: CRREL Report, 79-29
    Description / Table of Contents: An analytical study of the propagation of shock waves in snow was carried out to evaluate the response of medium density snow to high rates of loading. One solution was developed for steady shock waves; this resulted in calculation of pressure jump, density jump and stress wave speed. Correlation with available experimental data was found to be good. Nonsteady shock waves were also considered in order to evaluate wave attenuation rates in snow. Very few data were available to compare with the analytical results, so no definite conclusions on the part of the study could be made. The results show, however, that shock waves that produce plastic deformation attenuate at extremely high rates and that differences in pressure between two waves are quickly eliminated within a short distance. Calculations were also made to evaluate the effect of wave frequency on attenuation rates. The results show that, for plastic waves, frequency is not a predominant factor for determining attenuation rates.
    Type of Medium: Series available for loan
    Pages: v, 14 Seiten , Illustrationen
    Series Statement: CRREL Report 79-29
    Language: English
    Note: CONTENTS Abstract Preface Nomenclature I. Introduction II. A constitutive law for snow and balance principles III. Compatibility laws and jump equations for stress waves IV. Steady shock waves in snow V. Comparison of steady-wave theory with experimental results VI. A numerical solution to the nonsteady wave problem VII. Jump equations for nonsteady shock waves VIII. Reduced jump equations Discussion and conclusions Literature cited
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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-201-79/27
    In: CRREL Report, 79-27
    Description / Table of Contents: Some Bessel function identities found by solving problems of the deflection of a floating ice plate by two different methods are rigorously proved. The master formulas from which all the identities are derived are in a Fourier reciprocal relationship, connecting a Hankel function to an exponential function. Many new formulas can be derived from the master formulas. The analytical method presented here now opens the way to study a hitherto impossible type of problem--the deflection of floating elastic plates of various shapes and boundary conditions.
    Type of Medium: Series available for loan
    Pages: ii, 13 Seiten , Illustrationen
    Series Statement: CRREL Report 79-27
    Language: English
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  • 3
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-79/28
    In: CRREL Report, 79-28
    Description / Table of Contents: Transmission and scanning electron micrographs of Umiat bentonite revealed thin, mica-like grains with irregular shapes. Most of the bentonite showed electron diffraction ring patterns, but some showed hexagonal net patterns as well as ring patterns. The lengths of the unit cells were calculated to be 5.18 A along the a-axis and 8.97 A along the b-axis. Semiquantitative analyses were made using an energy dispersive spectrometer. Common elements such as Si, Ti, Al, Fe, Mg, Na and K were determined. The molecular ratio of SiO2:Al2O3 was calculated to be 492:100 for the bulk sample, indicating that Umiat bentonite is similar in most respects to Wyoming bentonite, and is classified as a mont-morillonite. The microstructure of frozen Umiat bentonite was observed at a specimen temperature of -100 C using a scanning electron microscope equipped with a cold stage. Frozen bentonite and segregated ice patterns formed from wet bentonite were examined using an X-ray map and Si X-ray line scan. Sublimation processes of ice in the frozen bentonite were observed at specimen temperatures of -60 and -80 C. After sublimation of the ice the bentonite displayed a honeycomb structure. It was concluded that the freezing-sublimation cycle in frozen soil increases the permeability of water vapor due to the three-dimensional structure of the coagulated clay formed by freezing.
    Type of Medium: Series available for loan
    Pages: iii, 14 Seiten , Illustrationen
    Series Statement: CRREL Report 79-28
    Language: English
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  • 4
    Call number: ZSP-201-79/25
    In: CRREL Report, 79-25
    Description / Table of Contents: The motion of dislocations in single crystal ice under an electric field was observed by using X-ray topographic methods. Electric charge density on these dislocations was deduced from the amplitude and length of the dislocation segment under the known AC electrical field. The most likely linear charge density was about +5x10^-11 c/m, although considerable variation is possible depending on the effective field acting on the dislocation lines.
    Type of Medium: Series available for loan
    Pages: iii, 12 Seiten , Illustrationen
    Series Statement: CRREL Report 79-25
    Language: English
    Note: CONTENTS Abstract Preface Introduction Theory Experimental apparatus and procedure Results Discussion Concluding remarks Selected bibliography Appendix A. Mosotti type field on core of cylindrical cavity
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  • 5
    Call number: ZSP-201-79/26
    In: CRREL Report, 79-26
    Description / Table of Contents: A 19-year record of the annual closing and opening dates of operation of the Lake Champlain ferry at Grand Isle, Vermont, which are controlled by the lake's ice cover, was made available to CRREL. These navigation records accurately approximated the freeze-over and breakup dates for the ferry crossing area between Gordon Landing, Vermont, and Cumberland Head, New York. When compared statistically with water temperature and climatological data for the same years at nearby Lake Champlain locations, the dates allowed accurate predictions of ice formation. From nearby air temperature records, cumulative freezing degree-day (deg C) curves were plotted for each year of record, and ice formation dates and standard deviations were predicted with considerable accuracy. Several methods of predicting ice formation on Lake Champlain were attempted. The most accurate approach used a combination of water temperatures and freezing degree-days. The influence of wind speed on ice cover formation and prediction are also discussed in the report.
    Type of Medium: Series available for loan
    Pages: v, 21 Seiten , Illustrationen
    Series Statement: CRREL Report 79-26
    Language: English
    Note: CONTENTS Abstract Preface Introduction Data tabulation and collection Air temperatures 11-reezing degree-days Water temperatures Closing and opening dates Results Air temperature Freezing degree-days Water temperatures Analysis: Attempted methods of predicting ice formation Predicting air temperatures 8Summer water temperatures Fall water temperatures and freezing degree-days Wind speed influence on closing of the lake Water temperature vs surface air temperature analysis Prediction of ice-out dates Conclusions Literature cited Appendix A. Freezing degree-day curves with ice notations and watertemperature notations Appendix B. Summary
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  • 6
    Call number: ZSP-201-79/24
    In: CRREL Report, 79-24
    Description / Table of Contents: By using a new thermocoring technique, a hole was successfully drilled through the 416-m thickness of the Ross Ice Shelf at J-9 Camp. This report provides a description of the drill and an account of this drilling project. A provisional examination of the core shows the ice shelf to consist of 410 m of snow and glacial ice underlain by 6 m of sea ice formed by direct freezing of sea water to the bottom of the Ross Ice Shelf.
    Type of Medium: Series available for loan
    Pages: ii, 12 Seiten , Illustrationen
    Series Statement: CRREL Report 79-24
    Language: English
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  • 7
    Call number: ZSP-201-79/23
    In: CRREL Report, 79-23
    Description / Table of Contents: The performance of surface impedance and magnetic induction electromagnetic subsurface exploration techniques was studied seasonally at various sites in Alaska where permafrost and massive ground ice occurred. The surface impedance method, which uses radiowaves in the LF and VLF bands, and the magnetic induction method, which uses low-frequency magnetic induction fields, distinguish subsurface materials by the electrical resistivity of the materials. The methods used have greatest sensitivity within about 20 m of the surface and are, therefore, most applicable for shallow subsurface investigations. The selection of study sites was based on anticipated contrasts in electrical resistivity between ground ice and adjacent earth materials. A magnetic induction instrument, using a separation of 3.66-m between the transmitter and receiver antennas, in general was able to detect near-surface zones of massive ice and to provide data regarding permafrost distribution in both the Fairbanks and Prudhoe Bay areas. At this antenna separation, the depth of magnetic field penetration was sufficient to include mainly the zone containing maximum contrasts in resistivity between ground ice and other earth materials. In the Fairbanks area, contrasts, in this zone were greatest in late winter when the seasonally thawed surface layer was completely frozen. When thawed, this layer usually becomes more conductive and often masks the deeper resistivity contrasts. In the Prudhoe Bay area, maximum ground resistivity contrasts were detected in late summer when shallow subsurface temperatures had risen sufficiently to permit resistivity contrasts between the massive ice and the ice-rich ground to appear.
    Type of Medium: Series available for loan
    Pages: v, 24 Seiten , Illustrationen
    Series Statement: CRREL Report 79-23
    Language: English
    Note: CONTENTS Abstract Preface Introduction Background Obiectives and procedures Ground electrical resistivity in permafrost regions Electromagnetic techniques General Magnetic induction method Surface impedance fradiowave method Direct current method General description of field sites Results Site 1 CRREL permafrost station, Fairbanks, Alaska Site 2 Planned road cut for Steese Highway near Fox, Alaska Site 3 Relic floodplain near Fairbanks, Alaska Site 4 Pingos, Prudhoe Bay, Alaska Site 5 Ice wedges, Prudhoe Bay, Alaska Comparisons between the surface impedance and magnetic induction methods Conclusions and recommendations Literature cited Appendix A. Discussion of the depth of sensitivity of the magnetic induction method using two- and three-layer apparent resistivity curves
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  • 8
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-79/30
    In: CRREL Report, 79-30
    Description / Table of Contents: The ice suppression resulting from discharge of warm water into rivers during winter is analyzed with emphasis on two different cases. In Part 1 the case of a thermal effluent fully mixed across the flow section is analyzed to include the effects of unsteadiness in the effluent temperature and the meteorological variations. The location of the ice edge is determined either by a 0 C water temperature criterion or an equilibrium ice melting analysis. The choice of the applicable criterion emerges naturally from the analysis even though the location of the ice edge may be considerably different when a steady-state analysis is done. In Part 2 the case of a side discharge of heated effluent is analyzed, also in an unsteady manner, and the effects of transverse dispersion are included in the analysis. Comparisons are made in both Parts 1 and 2 to limited field data that are available.
    Type of Medium: Series available for loan
    Pages: iv, 23 Seiten , Illustrationen
    Series Statement: CRREL Report 79-30
    Language: English
    Note: CONTENTS Abstract Preface Part I. Unsteady suppression of river ice by fully mixed thermal effluents Introduction Governing equations Outline of analysis Location of ice edge Numerical simulation Uncertainties and Imitations Literature cited Part II. Effect of transverse mixing on ice suppression Introduction Analysis of dispersion and heat loss Analysis of ice thickening and melting Numerical simulation Example simulations Field comparison Uncertainties and limitations Literature Cited Appendix A: Computer program for unsteady fully mixed ice suppression Appendix B: Computer program for unsteady lateral mixing ice suppression
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