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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-201-78/21
    In: CRREL Report, 78-21
    Description / Table of Contents: This study investigates the possibility of providing estimates of the time of occurrence and length of the freezing season for any location in East and West Germany by using the average Januavy air temperature (AJ AT) as an index. The results indicate that reliable values of the mean freezing index can be obtained from the AJAT relationships which are developed for Germany. This association is further verified using data from the northeastern part of the U.S., and the AJ AT is then used to determine the average starting and ending dates (and hence the probable length) of the freezing season for stations in Germany. The AJ AT and the average dates of snowfall occurrence for numerous locations in the U.S. and Germany are also correlated. Interrelationships between these parameters and the average number of days with snow on the ground for stations up to 3000 m in elevation in Germany are examined. A detailed AJ AT map for East and West Germany, in which data from 134 stations, latitude, altitude and regional influences are considered, is developed in order to make the relationships usable. A historical review of the literature on snow studies in Germany and a brief discussion of snow-cover interpretation by satellite photography are included
    Type of Medium: Series available for loan
    Pages: v, 48 Seiten , Illustrationen , 1 Karte
    Series Statement: CRREL Report 78-21
    Language: English
    Note: CONTENTS Abstract Preface Introduction Historical literature review Relationships between midwinter temperature and freezing season Mean freezing index 4 Average January air temperature U.S. comparative study Correlation of AJAT and duration of freezing season Relationships between average January air temperature and snow conditions U.S. relationships German relationships Mapping of average January air temperatures Analysis of observed AJ AT data Development of detailed maps Application and discussion Examples Influence of vegetation Literature cited Appendix A. interpretation of snow cover by satellite Appendix B. Contour, station elevation and Aj AT maps for East and West Germany
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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-201-78/18
    In: CRREL Report, 78-18
    Description / Table of Contents: The primary objective of this project was to demonstrate the utility of remote sensing techniques as an operational tool in the acquisition of data required by the U.S. Army Corps of Engineers, Seattle District, in the Grays Harbor dredging effects project, and related projects. Aerial imagery was used to map surface circulation and suspended sediment patterns near the hopper dredge pump site at the harbor entrance and near pulpmill outfalls in Aberdeen, and to map the areal distribution and extent of intertidal habitats. The surface circulation maps prepared from the aerial photographs and thermal imagery compared favorably with the large-scale circulation patterns observed in the Grays Harbor hydraulic model at the U.S. Army Engineer Waterways Experiment Station. Of the imagery provided by NASA, the thermal imagery was more useful than the color or color infrared (CIR) photographs for mapping circula­tion, while the CIR photographs were more useful than the thermal imagery or the color photographs for mapping intertidal habitats. Current velocities estimated from dye dispersion patterns and drifting dye drogues were comparable at some locations to velocities measured by in situ current meters and in the hydraulic model. Based on a cursory evaluation of LANDSAT-1 imagery acquired in January, February, and October 1973, it had limited utility in providing data on surface circulation patterns in Grays Harbor. The areal distribution and extent of nine wetland vegetation types, dune vegetation, and three types of eelgrass were mapped using primarily aerial C IR photographs and ground sur­veys. Color photographs were also used for areas not covered by the C IR photographs. Wetland vegetation types mapped were: low silty marsh, low sandy marsh, sedge marsh, high immature marsh, high mature marsh, salt marsh, diked pasture, freshwater marsh, and wooded swamp. Undiked salt marsh (first five types) covered 5540 acres (22.3 km2) in Grays Harbor.
    Type of Medium: Series available for loan
    Pages: vi, 85 Seiten , Illustrationen
    Series Statement: CRREL Report 78-18
    Language: English
    Note: CONTENTS Abstract Preface Introduction Site description Background and objectives Project history Approach General Aircraft imagery and sensor data LANDSAT imagery Ground truth data Results and discussion Remote sensing techniques Conventional techniques Comparison of results Conclusions Advantages and disadvantages Applications Recommendations Literature cited
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  • 3
    Call number: ZSP-201-78/9
    In: CRREL Report, 78-9
    Description / Table of Contents: Large, simply supported beams of temperate lake ice were found, generally, to yield significantly higher flexural strengths than the same beams tested in the cantilever mode. Data support the view that a significant stress concentration may exist at the fixed corners of the cantilever beams. Maximum effects are experienced with beams of cold, brittle ice substantially free of structural imperfections; for this kind of ice the strength difference factor, here attributed to the effect of stress concentrations, may exceed 2.0; that is, simply supported beams test a factor of 2 or more stronger than the same beams tested in the cantilever mode. In ice that has undergone extensive thermal degradation, the stress concentration effect may be eliminated entirely. Simply supported beams generally yield higher strengths when the top surfaces are placed in tension. This behavior is attributed to differences in ice type; the fine-grained, crack-free top layer of snow-ice which constituted up to 50% of the ice cover in the current series of tests usually reacted more strongly in tension than the coarse-grained crack-prone bottom lake ice.
    Type of Medium: Series available for loan
    Pages: iv, 14 Seiten , Illustrationen
    Series Statement: CRREL Report 78-9
    Language: English
    Note: CONTENTS Abstract Preface Introduction Test sites and ice cover properties Beam testing Results Discussion Conclusions Literature cited
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  • 4
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-78/8
    In: CRREL Report, 78-8
    Description / Table of Contents: The interaction of a 5.1-GHz transverse electric surface wave with a dielectric slab is experimentally investigated. The wave is initially supported by a dielectric substrate resting upon a metallic ground-plane. A slab, made of the same dielectric material as the substrate and variable in height, is then placed upon the waveguide. The results for a small slab sitting on the substrate showed that the discontinuity was a very inefficient launcher of reflected surface waves. Investigations of these reflections with a trough waveguide showed that, for values of slab height comparable to the exponential decay height of the surface wave, the reflections remain very small. However, as the slab height is increased beyond the decay height, the reflected amplitude approaches the theoretical value for a plane wave reflected from the interface between air and the same dielectric. The results are applicable to surface wave methods of microwave deicing of wings and helicopter rotors.
    Type of Medium: Series available for loan
    Pages: v, 16 Seiten , Illustrationen
    Series Statement: CRREL Report 78-8
    Language: English
    Note: CONTENTS Abstract Preface Summary Introduction Background Objective and procedure Theory of plane surface waves Waveguide design and characteristics Physical apparatus Frequency characteristics Spatial distribution of Ey above the guide Guide wave length Surface wave interaction with a slab discontinuity Experiments with a trough Discussion and conclusions Literature cited
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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-201-78/7
    In: CRREL Report, 78-7
    Description / Table of Contents: The theory of non-coaxial in-plane plastic deformation of soils that obey the Coulomb yield criterion is presented. The constitutive equations are derived by use of the geometry of the Mohr circle and the theory of characteristic lines. It is found that, for solving a boundary value problem, the non-coaxial angle must be given such values that enable us to accommodate the presupposed type of flow in the given domain satisfying the given boundary conditions. The non-coaxial angle is contained in the constitutive equations as a parameter. Therefore, the plastic material obeying the Coulomb yield criterion is a singular material whose constitutive equations are not constant with material but are variable with flow conditions.
    Type of Medium: Series available for loan
    Pages: iii, 28 Seiten , Illustrationen
    Series Statement: CRREL Report 78-7
    Language: English
    Note: CONTENTS Abstrac Preface Introduction Analysis of stress Geometry of the Mohr circle Stress characteristic directions Analysis of strain rate Constitutive equations Strain-rate characteristic directions Constitutive geometry Strain-rate tensor The dyadic expression Plastic work rate Coordinate transformation Example The stress solution Velocity equations in the a-characteristic curvilinear coordinates The constant speed solution Velocity equations in the constant density region Solution in the first constant-density subregion Solution in the second constant-density subregion Solution in the passive region Conclusion Literature cited
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  • 6
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-78/6
    In: CRREL Report, 78-6
    Description / Table of Contents: A new freezing mechanism, called segregation freezing, is proposed to explain the generation of the suction force that draws pore water up to the freezing surface of a growing ice lens. The segregation freezing temperature is derived by applying thermodynamics to a soil mechanics concept that distinguishes the effective pressure from the neutral pressure. The frost-heaving pressure is formulated in the solution of the differential equations of the simultaneous flow of heat and water, of which the segregation freezing temperature is one of the boundary conditions.
    Type of Medium: Series available for loan
    Pages: iv, 13 Seiten , Illustrationen
    Series Statement: CRREL Report 78-6
    Language: English
    Note: CONTENTS Abstract Preface Nomenclature Introduction Segregation freezing Analysis Heat conduction in the nascent ice layer Water flow in the unfrozen soil Heat transfer in the unfrozen soil Energy balance at the segregation-freezing front Numerical computation Literature cited Appendix A. Essence of Portnov’s method Appendix B. Frost-heaving without air available
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  • 7
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-78/3
    In: CRREL Report, 78-3
    Description / Table of Contents: The mathematical theory for the bearing capacity of river ice for vehicles is presented. The floating ice sheet is assumed to have simple supports at the shore line. Solutions are presented for loads uniformly distributed over circular and rectangular areas. Numerical evaluations are made for a number of vehicles and the results presented in graphical form
    Type of Medium: Series available for loan
    Pages: iii, 22 Seiten , Illustrationen
    Series Statement: CRREL Report 78-3
    Language: English
    Note: CONTENTS Abstract Preface Conversion factors: U.S. customary to metric (SI) units of measurement Introduction Theory Solution by superposition Solution by Fourier integral Solution by Fourier series Application and results Literature cited Appendix A: Bearing capacity of river ice for military vehicles Appendix B: Vehicle specifications Appendix C: Fortran II computer program
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  • 8
    Call number: ZSP-201-78/4
    In: CRREL Report, 78-4
    Description / Table of Contents: The use of radio-echo sounding records to indicate the presence of internal layers within large ice sheets is of interest to glaciologists because it offers a means of tracking the internal properties of the ice sheets over large distances. The interpretation of the reflections obtained in this manner is more valuable, however, if a physical property change relating to the glaciological regime can be related to the dielectric property change producing the radio-echo reflections. In this report, we use the measured physical properties of core to bedrock taken at Cape Folger, East Antarctica (66 deg 22 min s, 111 deg (E), 324-m depth), to compute a profile of dielectric properties and from this, a depth-reflection coefficient profile for comparison with observed radio-echo reflections. The measurements available on physical properties are: density variations, bubble size and shape changes, and crystal fabric variations. The depths of the strong reflections shown on the available radio-echo records are in reasonable agreement with the depths corresponding to the highest reflection coefficients computed from the combined physical property measurements. In calculations to differentiate the separate effects of different physical properties, it appears that density variations account for the primary contributions to the calculated dielectric property changes corresponding to the highest reflection coefficients. However, bubble changes alone can also account for reasonable, though lower, reflection coefficients at the appropriate depths. Crystal fabric variations correspond poorly with the reflection locations. Density variations are normally associated with depositional events in the history of the ice sheet.
    Type of Medium: Series available for loan
    Pages: vi, 12 Seiten , Illustrationen
    Series Statement: CRREL Report 78-4
    Language: English
    Note: CONTENTS Abstract Preface Nomenclature Introduction Derivation of the power reflection coefficient-depth variation Possible sources of dielectric constant variation with depth in ice sheets Ice density variations Effect of macroscopic impurity layers Effect of microscopic impurtty layers Changes in inclusion geometry Effect of crystal orientation changes Physical properties of the Cape Folger core Density-depth profile Air bubble-geometry depth profile Crystal orientation-depth profile Radio-echo sounding data Results and conclusions Literature cited
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  • 9
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-78/2
    In: CRREL Report, 78-2
    Description / Table of Contents: Many of the technical questions relating to iceberg transport are given brief, but quantitative, consideration. These include iceberg genesis and properties, the mechanical stability of icebergs at sea, towing forces and tug characteristics, drag coefficients, ablation rates, and handling and processing the iceberg at both the pick-up site and at the final destination. In particular the paper attempts to make technical information on glaciological and ice engineering aspects of the problem more readily available to the interested planner or engineer. Specific conclusions include: (1) No unprotected iceberg, no matter how long or wide, would be likely to survive the ablation caused by a long trip to low latitudes. (2) Icebergs that have a horizontal dimension exceeding 2 km may well be prone to breakup by long wavelength swells. (3) To avoid the dangers associated with an iceberg capsizing, the width of a 200-m thick iceberg should always be more than 300 m. (4) For towing efficiency the length/width ratio of a towed iceberg should be appreciably greater than unity. (5) For a pilot project, the selected iceberg would have to be quite small, if for no other reason than the practical availability of tug power.
    Type of Medium: Series available for loan
    Pages: v, 31 Seiten , Illustrationen
    Series Statement: CRREL Report 78-2
    Language: English
    Note: CONTENTS Abstract Preface Introduction Sources and properties of tabular icebergs Sources Characteristics of ice shelves near the ice front Characteristics of tabular icebergs Towing Geophysical and engineering considerations Tug characteristics Handling and processing Cutting and boring with thermal devices Penetration with electrothermal devices Electrothermal cutting Making vertical cuts by pre-split blasting Primary fragmentation by blasting Primary fragmentation by mechanical sawing Comminuting ice with machines Slurry pipelines Conclusion Literature cited
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  • 10
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-78/1
    In: CRREL Report, 78-1
    Description / Table of Contents: The results of axial double point-load tests on disk samples of snow and ice obtained from the area of McMurdo Sound, Antarctica, are presented. They show the effects of temperature, sample length, load point diameter and specific gravity on failure load. It was determined that 13 samples should be tested to obtain a representative mean strength index. The results show that the axial double point-load test has good possibilities as a rapid field test for determining the unconfined comrpessive strength of snow and ice but that further evaluation of the variables affecting test results must be made.
    Type of Medium: Series available for loan
    Pages: iii, 11 Seiten , Illustrationen
    Series Statement: CRREL Report 78-1
    Language: English
    Note: CONTENTS Abstract Preface Introduction Test procedure Test program Test samples Number of test for determining strength index Effect of temperature Effect of sample length Effect of load point size Tests on snow Discussion Recommendations Literature cited
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