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  • Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory  (53)
  • English  (53)
  • Bulgarian
  • Chinese
  • 2015-2019
  • 1985-1989  (53)
  • 1945-1949
  • 1
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    Effect of grain size on the internal fracturing of polycrystalline ice (1986)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-86/5
    In: CRREL Report, 86-5
    Description / Table of Contents: This work presents the results of a study to examine the effects of grain size of internal microfractures in polycrystalline ice. Laboratory-prepared specimens were tested under uniaxial, constant-load creep conditions at -5 C. Grain size ranged from 1.5 to 6.0 mm. This range of grain size, under an initial creep stress of 2.0 MPa, led to a significant change in the character of deformation. The finest-grained material displayed no internal cracking and typically experienced strains of 10 to the minus 2nd power at the minimum creep rate epsilon. The coarse-grained material experienced severe cracking and a drop in the strain at epsilon min to approximately 4x10 to the minus 3rd power. Extensive post-test optical analysis allowed estimation of the size distribution and number of microcracks in the tested material. These data led to the development of a relationship between the average crack size and the average grain size. Additionally, the crack size distribution, when normalized to the grain diameter, was very similar for all specimens tested. The results indicate that the average crack size is approximately one-half the average grain diameter over the stated grain size range. A dislocation pileup model is found to adequately predict the onset of internal cracking. The work employed acoustic emission techniques to monitor the fracturing rate occurred. Other topics covered in this report include creep behavior, crack healing, the effect of stress level on fracture size and the orientation of cracked grains. Theoretical aspects of the grain size effect on material behavior are also given.
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    Pages: v, 79 Seiten , Illustrationen
    Series Statement: CRREL Report 86-5
    URL: https://apps.dtic.mil/docs/citations/ADA171571
    URL: https://hdl.handle.net/11681/9321
    Language: English
    Note: CONTENTS Abstract Preface Background Present research in perspective Explanations of the grain-size dependency Grain size effects on the ductile to brittle transition Nucleation mechanisms and modeling Characteristic size of nucleated crack Cracking in ice Detection of internal fracturing by acoustic emission techniques Test methods Specimen preparation Creep testing apparatus Crack length and crack density measurements Crack healing measurements Thin section photographs Grain size determination Acquisition of acoustic emission data Presentation of results Specimen characteristics Microcrack measurements Creep behavior Crack healing Slip plane length distribution Acoustic emission observations Grain orientation Analysis and discussion Thick section observations The grain size vs crack size relationship Crack nucleation condition Crack density and specimen strain Creep behavior Normalized crack length Location of cracks Acoustic emission activity Summary and conclusions Suggestions for future work Literature cited Appendix A: Crack length histograms Appendix B: Crystal orientations
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  • 2
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    Applications of the finite-element method to the problem of heat transfer in a freezing shaft wall (1986)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-86/8
    In: CRREL Report, 86-8
    Description / Table of Contents: In this work, numerical computations of heat transfer for freezing a shaft wall have been conducted. Both fixed mesh and deforming mesh finite-element methods are used. In the fixed mesh method, latent heat effects are accounted for through a δ function in the apparent heat capacity. In the deforming mesh method, an automatic mesh-generation technique with transfinite mappings is used, and in this method two different approaches are taken to evaluate the movement of the interface. The freeze-pipes are considered as point sources with irregular distribution. The advancement of the inner and outer boundaries of the frozen wall is found to be in agreement with the previously computed results
    Type of Medium: Series available for loan
    Pages: iii, 31 Seiten , Illustrationen
    Series Statement: CRREL Report 86-8
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a172552.pdf
    URL: http://hdl.handle.net/11681/9433
    Language: English
    Note: CONTENTS Abstract Preface Introduction Basic finite-element formulas Description of problem Finite-element equation-fixed mesh Finite-element equation-deforming mesh Transfinite mapping technique Computations and conclusions Literature cited Appendix A : Point heat sources Appendix B: Evaluation of the integral including latent heat (fixed mesh) Appendix C: Specification of [K] -deforming mesh Appendix D: Specifying δΤ/δn and the direction of mj for method I Appendix E: Procedures of method 2 Appendix F: Explanation of programs
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  • 3
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    A theory for the scalar roughness and the scalar transfer coefficients over snow and sea ice (1986)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-86/9
    In: CRREL Report, 86-9
    Description / Table of Contents: The bulk aerodynamic transfer coefficients for sensible (C sub H) and latent (C sub E) heat over snow and sea ice surfaces are necessary for accurately modeling the surface energy budget but are very difficult to measure. This report therefore presents a theory that predicts C sub H and C sub E as functions of the wind speed and a surface roughness parameter. The crux of the model is establishing the interfacial sublayer profiles of the scalars, temperature and water vapor, over aerodynamically smooth and rough surfaces. These interfacial sublayer profiles are delivered from surface-renewal model in which turbulent eddies continually sweep down to the surface, transfer scalar contaminants across the interface by molecular diffusion, and then burst away. Matching the interfacial sublayer profiles with the usual semilogarithmic inertial sublayer profiles yields the roughness lengths for temperature and water vapor. With these and a model for the drag coefficient over snow and sea ice based on actual measurements, the transfer coefficients are predicted. C sub E is always a few percent larger than C and H. Both decrease monotonically with increasing wind speed for speeds above 1 m/s, both increase at all winds speeds as the surface gets rougher. Both, nevertheless, are almost between 0.0010 and 0.0015.
    Type of Medium: Series available for loan
    Pages: vi, 26 Seiten , Illustrationen
    Series Statement: CRREL Report 86-9
    URL: https://apps.dtic.mil/docs/citations/ADA174089
    URL: http://hdl.handle.net/11681/9435
    Language: English
    Note: CONTENTS Abstract Preface Nomenclature Introduction Aerodynamically rough surface Aerodynamically smooth surface Scalar transfer coefficients Conclusions Literature cited
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  • 4
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    Resilient modulus of freeze-thaw affected granular soils for pavement design and evaluation; Part 2: Field validation tests at Winchendon, Massachusetts, test sections (1986)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-86/12
    In: CRREL Report, 86-12
    Description / Table of Contents: Stress-deformation data for six granular soils ranging from sandy silt to dense-graded crushed stone were obtained from in-situ tests and laboratory tests. Surface deflections were measured in the in-situ tests, with repeated-load plate-bearing and falling-weight deflectometer equipment, when the six granular soils were frozen, thawed, and at various stages of recovery from thaw weakening. The measured deflections were used to judge the validity of procedures developed for laboratory triaxial tests to determine nonlinear resilient moduli of specimens in the frozen, thawed, and recovering states. The validity of the nonlinear resilient moduli, expressed as functions of externally applied stress and moisture tension, was confirmed by using the expressions to calculate surface deflections that were found to compare well with deflections measured in the in-situ tests. The tests on specimens at various stages of recovery are especially significant because they show a strong dependence of the resilient modulus on moisture tension, leading to the conclusion that predictions or in-situ measurements of moisture tension can be used to evaluate expected seasonal variation in the resilient modulus of granular soils.
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    Pages: v, 70 Seiten , Illustrationen
    Series Statement: CRREL Report 86-12
    URL: http://hdl.handle.net/11681/9326
    Language: English
    Note: CONTENTS Abstract Preface Introduction Sampling of test section Laboratory tests Asphalt concrete Natural subgrade material Test soils Field tests Analysis of field-loading tests Discussion Conclusions Literature cited Appendix A: Field data Appendix 8: Ground temperatures prevailing during plate-loading tests Appendix C: Measured surface deflections compared with deflections calculated by NELAPAV Appendix D: Resilient moduli and supporting data calculated by NELAPAV
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  • 5
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    Resilient modulus of freeze-thaw affected granular soils for pavement design and evaluation; Part 4: Field validation tests at Albany County Airport (1986)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-86/13
    In: CRREL Report, 86-13
    Description / Table of Contents: Stress-deformation data for six granular soils ranging from sandy silt to dense-graded crushedstone were obtained from in-situ tests and laboratory tests. Surface deflections were measured in the in-situ tests, with repeated-load plate-bearing and falling-weight deflectometer equipment, when the six granular soils were frozen, thawed, and at various stages of recovery from thaw weakening. The measured deflections were used to judge the validity of procedures developed for laboratory triaxial tests to determine nonlinear resilient moduli of specimens in the frozen, thawed, and recovering states. The validity of the nonlinear resilient moduli, expressed as functions of externally applied stress and moisture tension, was confirmed by using the expressions tocalculate surface deflections that were found to compare well with deflections measured in the in-situ tests. The tests on specimens at various stages of recovery are especially significant because they show a strong dependence of the resilient modulus on moisture tension, leading to the conclusion that predictions or in-situ measurements of moisture tension can be used to evaluate expected seasonal variation in the resilient modulus of granular soils.
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    Pages: iv, 148 Seiten , Illustrationen
    Series Statement: CRREL Report 86-13
    URL: http://hdl.handle.net/11681/9463
    Language: English
    Note: CONTENTS Abstract Preface Introduction Test sections Installing instruments and sampling Laboratory tests Asphalt concrete Base, subbase and subgrade soils Data analysis for base, subbase and subgrade soils Field tests Analysis of plate loading tests Analytical approach Results Discussion Conclusions Literature cited Appendix A: Field data Appendix B: Ground temperatures, moisture tension, water table and freezing iso-therms prevailing during plate loading tests Appendix C: Measured surface deflections compared with deflections calculated by NELAPAV Appendix D: Resilient moduli and supporting data calculated by NELAPA V at radius 0.0, taxiways A and B.
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  • 6
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    Prototype drill for core sampling fine-grained perennially frozen ground (1985)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-85/1
    In: CRREL Report, 85-1
    Description / Table of Contents: An expensive drill has been modified to provide researchers with the ability to auger an open hole or to acquire continuous, undisturbed 76-mm-diam core samples of a variety of perennially frozen materials that are suitable for chemical and petrographic analysis. It was developed by field testing in support of research from 1980 to 1983. Operation of the drill is based mainly on using a minimum of power to cut through frozen ground with tungsten carbide cutters on a CRREL coring auger. The ice content, temperature and grain size of the frozen sediments are important variables determining the sampling depth. Perennially frozen sediments with temperatures in the range of -0.5 C to -8.5 C have been continuously cored with this drill. Drilling and sampling are most efficiently conducted when ambient air temperatures are below freezing and the active layer is frozen. The self-contained lightweight drill is readily transportable off-road by helicopter or tracked vehicle, or by towing over roads. It is locally self-mobile by use of a winch. Total cost of the drill and modifications is estimated at approximately $10,000.
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    Pages: v, 34 Seiten , Illustrationen
    Series Statement: CRREL Report 85-1
    URL: https://apps.dtic.mil/docs/citations/ADA152388
    URL: https://hdl.handle.net/11681/9352
    Language: English
    Note: CONTENTS Abstract Preface Introduction Background on development Drill development and configuration Equipment Modifications Operations Assembly and disassembly Field transport and movement Typical operating procedures Effect of material properties, weather and water Depth and hole completion time Summary Literature cited
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  • 7
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    Effect of nonuniform size on internal stresses in a rapid, simple shear flow of granular materials : Part 2. Multiple grain sizes (1985)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-85/3
    In: CRREL Report, 85-3
    Description / Table of Contents: In the past all theoretical analyses for rapidly sheared granular flows assumed that the granular solids are either disks or spheres and are uniform in size. However, natural materials that create these granular flows are in general irregular in shape and have various spectra of sizes. The stress and rate of energy dissipation levels in granular flows are significantly influenced by the size distribution. In part 1 of this report series (AD-A154 045), the formulation of the constitutive equations considering a two-size granular mixture is presented, where the ratio of the two sizes is nearly one. In part 2, the constitutive equations for a two-size mixture are extended to include a general size ratio. In addition, a complete spectrum of size distribution is incorporated, which allows the quantification of the size distribution effect in the most general way. In analyzing the stresses, intergranular collision is assumed to be the major dynamic activity at the microscopic level. Because of the present limited knowledge of testing shape effects, the analysis is confined to the flow of either disks or spheres. The result of this work provides necessary information for a more realistic analysis of natural and industrial granular flow. Keywords: Granular flow, and Particle size distribution.
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    Pages: vi, 29 Seiten , Illustrationen
    Series Statement: CRREL Report 85-3
    URL: https://apps.dtic.mil/docs/citations/ADA154046
    URL: https://hdl.handle.net/11681/9350
    Language: English
    Note: CONTENTS Abstract Preface Nomenclature Introduction Constitutive equations for a two-size mixture Limiting case of the two-size mixture Complete spectrum analysis for spheres and disks Conclusion Literature cited Appendix A: Derivation of collision frequency between neighboring spheres that follow the mean shear flow without fluctuations
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  • 8
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    On the pressure drop through a uniform snow layer (1988)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-88/14
    In: CRREL Report, 88-14
    Description / Table of Contents: An experimental study covering a mass flow rate ranging from 1.62 to 67.45 g/cm2-s and snow density varying from 0.377 to 0.472 g/cm3 has been conducted. Pressure drops ranging from 0.012 to 2.868 gf/cm2 were recorded. A plot of the friction factor fp vs Rep (defined as the classical Reynolds number Re for fluid flow through conduits) showed a good representation of all the experimental data. The least-squares analysis resulted in an expression of f sub p = 118/Rep to the 1.095 power for snow, in comparison with the expression f sub p = 64/Rep developed for fluid flow through porous media of randomly packed metallic and nonmetallic materials of spherical and nonspherical shapes.
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    Pages: iv, 18 Seiten , Illustrationen
    Series Statement: CRREL Report 88-14
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a201045.pdf
    URL: https://hdl.handle.net/11681/9070
    Language: English
    Note: CONTENTS Abstract Preface Nomenclature Introduction Experimental setup and procedure Experimental results Discussion and conclusions Literature cited
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  • 9
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    Atmospheric icing and broadcast antenna reflections (1988)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-88/11
    In: CRREL Report, 88-11
    Description / Table of Contents: This study assesses the effects of atmospheric icing on broadcast transmission reflections on two mountains- Mount Mansfield in northern Vermont and Mount Washington in New Hampshire. Experience and theory suggest that antenna ice accretions produce large signal reflections. Correlations between reflection coefficients and ice accretions on Rosemount ice detectors adjacent to antennas were low and occasionally negative. The unexpected correlations may be due to factors not measured, such as antenna tuning, ice type and ice location on the antenna system. Other confounding factors may include ice detector performance and methods used to compute antenna ice accretions from the ice detectors.
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    Pages: iii, 19 Seiten , Illustrationen
    Series Statement: CRREL Report 88-11
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a200378.pdf
    URL: https://hdl.handle.net/11681/9069
    Language: English
    Note: CONTENTS Abstract Preface Introduction Data sources Study location and icing conditions Icing data Antenna reflection data Data preparation Analyses Conclusions Literature cited
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  • 10
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    Comparison of soil freezing curve and soil water curve data for Windsor sandy loam (1988)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-88/16
    In: CRREL Report, 88-16
    Description / Table of Contents: Unfrozen water content as a function of temperature was measured in the laboratory using nuclear magnetic resonance (NMR) for a Windsor sandy loam soil. The data were related to previously measured soil moisture retention data through the modified Clapeyron equation with suitable adjustment for surface tension. The results show the usefulness of extending the soil freezing curve to temperatures only slightly below freezing and the soil water curve to very great suction.
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    Pages: iii, 42 Seiten , Illustrationen
    Series Statement: CRREL Report 88-16
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a202365.pdf
    URL: https://hdl.handle.net/11681/9072
    Language: English
    Note: CONTENTS Abstract Preface Introduction Soil variable ø SWC and SFC similarity Mathematical representation of SWC and SFC data NMR measurement of unfrozen water content Characterization of SWC Discussion Conclusions Literature cited Appendix A: Soil freezing curve data Appendix B: Error analysis Appendix C: Soil water curve data
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  • 11
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    Ship model testing in level ice : an overview (1988)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-88/15
    In: CRREL Report, 88-15
    Description / Table of Contents: The main points covered are: (1)modeling criteria for ships in ice, which must take into account the presence of a solid boundary at the water surface; (2) types of model ice used in various tanks-saline ice, urea-doped ice, EG/AD/S ice and synthetic ice; (3) techniques for growing model ice sheets, and achieving and monitoring the required ice properties; (4) limitations of both model ice and property measurement techniques; (5) model testing procedures for EHP and SHP tests and their limitations; (6) comparison between model test results and available full-scale trials data; (7) existing empirical and analytical or semi-analytical algorithms for predicting ship performance in level ice; (8) current research at CRREL and other research facilities to improve modeling techniques and data interpretation; and (9) novel bow designs for ice-transiting vessels.
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    Pages: v, 39 Seiten , Illustrationen
    Series Statement: CRREL Report 88-15
    URL: https://apps.dtic.mil/docs/citations/ADA201012
    URL: https://hdl.handle.net/11681/9073
    Language: English
    Note: CONTENTS Abstract Preface Nomenclature Introduction General considerations Ice properties Modulus, E Characteristic length, Ic Flexural strength, σf Com pressive strength, σc Shear strength, σs Poisson's ratio, ϑ Fracture toughness, Kic Density, ρi Ice-hull friction factor, fi Model ice Synthetic ice Columnar saline ice Columnar carbamide ice Fine-grained ice EG/AD/S model ice Model test procedures Ice growth and monitoring EHP tests SHP test Test data analysis--comparison with full scale Analysis of test results Comparison with full-scale data Analytical and empirical predictors Empirical predictors Analytical and semi-analytical schemes Current research efforts in ice modeling International cooperative research Ice testing CRREL research on ship-ice interaction Novel icebreaking bow designs Conclusions and final remarks Literature cited
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  • 12
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    Profile properties of undeformed first-year sea ice (1988)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-88/13
    In: CRREL Report, 88-13
    Description / Table of Contents: In many sea ice engineering problems the ice sheet has been assumed to be a homogeneous plate whose mechanical properties are estimated from the bulk salinity and average temperature of the ice sheet. Typically no regard has been given to the vertical variation of ice properties in the ice sheet or to the time of ice formation. This paper first reviews some of the mechanical properties of sea ice, including the ice tensile, flexural and shear strengths, as well as the ice modulus. Equations for these properties are given as functions of the ice brine volume, which can be determined from the ice salinity and temperature. Next a numerical, finite difference model is developed to predict the salinity and temperature profiles of a growing ice sheet. In this model ice temperatures are calculated by performing an energy balance of the heat fluxes at the ice surface. The conductive heat flux is used to calculate the rate of ice growth and ice thickness by applying the Stefan ice growth equation. Ice salinities are determined by considering the amount of initial salt entrapment at the ice/water interface and the subsequent brine drainage due to brine expulsion and gravity drainage. Ice salinity and temperature profiles are generated using climatological data for the Central Arctic basin. The predicted salinity and temperature profiles are combined with the mechanical property data to provide mechanical property profiles for first-year sea ice of different thicknesses, grown at different times of the winter. The predicted profiles give composite plate properties that are significantly different from bulk properties obtained by assuming homogeneous plates. In addition the failure strength profiles give maximum strength in the interior of the sheet as contrasted with the usual assumption of maximum strength at the cold, upper ice surface. Surprisingly the mechanical property profiles are only a function of the ice thickness, independent of the time of ice formation.
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    Pages: v, 63 Seiten , Illustrationen
    Series Statement: CRREL Report 88-13
    URL: https://apps.dtic.mil/docs/citations/ADA213087
    URL: https://hdl.handle.net/11681/9071
    Language: English
    Note: CONTENTS Abstract Preface Introduction Structure Composition Mechanical properties Strength Elastic constants The temperature-salinity model Temperature profiles Salinity profiles Composite plate properties Results Conclusions Literature cited Appendix A: Details of the equations for ice surface temperature and conductive heat flux Appendix B: Calculated profile and bulk properties of an ice sheet of varying thickness Appendix C: Calculated profile and bulk properties of 30- and 91-cm-thick ice sheets
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  • 13
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    Measurement of the unfrozen water content of soils : comparison of NMR and TDR methods (1988)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-88/18
    In: CRREL Report, 88-18
    Description / Table of Contents: The results of a laboratory testing program, carried out to compare two independent methods for determining the unfrozen water content of soils, are described. With the time domain reflectometry method, the unfrozen water content is inferred from a calibration curve of apparent dielectric constant vs volumetric water content, determined by experiment. Previously, precise calibration of the TDR technique was hindered by the lack of a reference comparison method, which nuclear magnetic resonance now offers. This has provided a much greater scope for calibration, including a wide range of soil types and temperature (unfrozen water content). The results of the testing program yielded a relationship between dielectric constant and volumetric unfrozen water content that is largely unaffected by soil type, although a subtle but apparent dependency on the texture of the soil was noted. It is suggested that this effect originates from the lower valued dielectric constant for absorbed soil water. In spite of this, the general equation presented may be considered adequate for most practical purposes. The standard error of estimate is 0.015 cc/cc, although this may be reduced by calibrating for individual soils. Brief guidelines on system and probe design are offered to help ensure that use of the TDR method will give results consistent with the relationship presented.
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    Pages: ii, 16 Seiten , Illustrationen
    Series Statement: CRREL Report 88-18
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a203082.pdf
    URL: https://hdl.handle.net/11681/9074
    Language: English
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  • 14
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    Development and design of sludge freezing beds (1988)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-88/20
    In: CRREL Report, 88-20
    Description / Table of Contents: This study develops design criteria for a new sludge dewatering unit operation called a sludge freezing bed. This bed uses natural freeze-thaw to condition the sludge. The total depth of sludge that can be frozen, thawed and dewatered by this process in a year is the main criterion needed for design. Laboratory tests assessed the dewaterability of freeze-thaw conditioned water treatment plant sludge and both anaerobically and aerobically digested wastewater sludges at various depths. Mathematical models for predicting the design depth were developed; values for the input parameters to the models were obtained from the literature or from laboratory and pilot-scale experiments. The dewaterability tests indicated that the depth of sludge that can be applied is not limited by drainability. Up to 2.0 m of each sludge drained in minutes after freeze-thaw conditioning. Except for the aerobically digested sludge, the solids content after drainage is high enough to permit mechanical removal. The physical and thermal characteristics of frozen sludge were found to be equivalent to those of ice. An analysis of the freezing and thawing models reveals that the design of a freezing bed will depend on the duration and intensity of the freezing and thawing seasons.
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    Pages: v, 58 Seiten , Illustrationen
    Series Statement: CRREL Report 88-20
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a205955.pdf
    URL: https://hdl.handle.net/11681/9061
    Language: English
    Note: CONTENTS Abstract Preface Nomenclature Introduction Background Purpose Scope Literature review Fundamentals of freeze separation Applications of freeze separation technology Conclusions Concept development Background Site visits Final concept Dewaterability studies Sludge characteristics Specific resistance and capillary suction time Filtrate quality Drainage tests Drying tests Development of design models Basic energy balance relationship Development of freezing model Development of thawing model Other models Evaluation of sludge input parameters Frozen sludge density, ϱf Layer thickness, ϵ Settled solids fraction, θ Thermal conductivities, Kfs, Kss Latent heat of fusion, L Absorptance, α Freezing point, Tf Summary Evaluation of climatic input parameters Ambient air temperatures, Taf, Tat Insolation, I Convection coefficient, hc Use of models for design Freezing design depth Thawing design depth Validation Example Conclusions anid recommendations Literature cited Appendix A: Sludge freezing at the Salem, New Hampshire, Wastewater Treatment Plant
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  • 15
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    Airborne radar survey of a brash ice jam in the St. Clair River (1989)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-89/2
    In: CRREL Report, 89-2
    Description / Table of Contents: A brash ice jam in the South Channel of the St. Clair River was profiled in February 1987 using a helicopter-borne short-pulse radar operating in the UHF band near 500 MHz. During the same time, measurements of the brash ice depth and water temperature were made from a Coast Guard icebreaker. The returned radar pulses consisted of a strong coherent reflection from the water surface, preceded (and followed) by incoherent returns from the brash ice. The measured waveform time delays were then converted to mean freeboard height of the brash ice pieces above the water surface. Given the mean freeboard height, an estimate of the total brash ice thickness was made. This estimate was greater than the range of the direct shipboard measurements. The difference is believed due to differences between ice porosity above and below the water line, to melting within the ice and to partial submergence of some of the surface pieces. It is concluded that this technique could be used for mapping relative brash ice depth if the complexities of automating waveform analysis could be overcome.
    Type of Medium: Series available for loan
    Pages: iv, 25 Seiten , Illustrationen
    Series Statement: CRREL Report 89-2
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a206868.pdf
    URL: https://hdl.handle.net/11681/9064
    Language: English
    Note: CONTENTS Abstract Preface Introduction Objectives and procedures Equipment Radar Brash ice probe Temperature measurements St. Clair River ice conditions Results and discussion Thickness and temperature Size distribution Radar survey Discussion of errors Porosity Phase state of the ice Partial submergence of individual pieces Spectra of reflected energy Conclusions and recommendations Literature cited Appendix A: Laboratory verification of surface scattering from a simulated ice jam Appendix B: Display of digitized and processed data
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    Definition of research needs to address airport pavement distress in cold regions (1989)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-89/10
    In: CRREL Report, 89-10
    Description / Table of Contents: In early fall 1984, a questionnaire was sent to over 325 general aviation airports in cold regions. The results from over 200 responses were compiled and evaluated and over 20 airport managers were contacted for additional details. Site visits were made to 36 airports to obtain additional information. The most common pavement problems identified in the study were associated with non-traffic-related phenomena and include 1) pre-existing cracks reflecting through asphalt concrete overlays (in two years less), 2) thermal cracking, and 3) longitudinal cracking (at a construction joint). Most of the airports experienced 1) water pumping up through cracks and joints in the pavements during spring thaw, or 2) additional roughness due to differential frost heave in the winter, or both problems. Many airport managers reported that debris was generated at cracks during the winter and spring. Many pavement problems can be traced to the evolutionary history of general aviation airports and the lack of consideration for site drainage. Based on the recognition of these problems, several future research programs are identified.
    Type of Medium: Series available for loan
    Pages: v, 147 Seiten , Illustrationen
    Series Statement: CRREL Report 89-10
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a212238.pdf
    URL: https://hdl.handle.net/11681/9056
    Language: English
    Note: CONTENTS Abstract Preface Introduction Statement of the problem Purpose and scope Background - the physical environment and airport pavements Physical environment of study area Comparison of highway and general aviation airport pavements Types of pavements and surface treatments Pavement distress and condition rating Surveys of airport pavement distress Airport pavement performance problems in cold regions Cracking Distortion and pavement faulting Disintegration Inadequate skid resistance Improper maintenance Stripping Statement of research needs Basis for statement of research needs Performance of overlays Recycling/reconstructing airport pavements Drainage of airport pavement structures Eliminating/accommodating differential frost heave Evaluation of adequacy of design procedures Maintenance products and performance Control of transverse cracking Additives for asphalt concrete Performance documentation Wildlife conservation vs aircraft safety Literature cited Appendix A: Questionnaire and listing of airports contacted Appendix B: Summary listing of questionnaire responses Appendix C: Narrative summary of site visits
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  • 17
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    Brittleness of reinforced concrete structure under Arctic conditions (1986)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-86/2
    In: CRREL Report, 86-2
    Description / Table of Contents: The behavior of reinforced and unreinforced concrete beams was studied under impact loading at low temperatures, and the results were compared to the behavior of reinforcing steel (rebar) in Charpy-V impact tests. Transition temperatures as low as -30°C were obtained for the rebars in the Charpy-V tests whereas no brittle failures occured in the rebars in the reinforced concrete beams at the temperature as low as -63°C, even in beams whe're the rebars were Intentionally notched. The impact strength of unreinforced concrete increases considerably at lower temperatures, thus reducing cracking of reinforcedconcrete structures and significantly increasing the safety of lightly reinforced structures.
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    Pages: iii, 25 Seiten , Illustrationen
    Series Statement: CRREL Report 86-2
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a170792.pdf
    URL: https://hdl.handle.net/11681/9437
    Language: English
    Note: Abstract Preface Introduction Tests Test specimens Test methods Results Impact strength of beanms Ductility of beams Effect of notched bars Elastic deflection of beams Impact tests on rebars Conclusions and summary Literature cited Appendix A: Beam crack patterns Appendix B: Photomicrographs of failure surfaces of some steels
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  • 18
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    Experimental determination of heat transfer coefficients in water flowing over a horizontal ice sheet (1986)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-86/3
    In: CRREL Report, 86-3
    Description / Table of Contents: Experiments to study the melting of a horizontal ice sheet with a flow of water above it were conducted in a 35 m long refrigerated flume with a cross section of 1.2x1.2 m. Water depth, temperature, and velocity were varied as well as the temperature and initial surface profile of the ice sheet. The heat transfer regimes were found to consist of forced turbulent flow at high Reynolds numbers with a transition to free convection heat transfer. There was no convincing evidence of a forced laminar regime. The data were correlated for each of the regimes, with the Reynolds number, Re, or the Grashof number combined with the Reynolds number as Gr/Re to the 2.5 power used to characterize the different kinds of heat transfer. For water flowing over a horizontal ice sheet, the melting heat flux, for low flow velocities, was not found to drop below the value for the free convection case-488.5 W/sq m-as long as the water temperature exceeds 3.4 C. This is significant since the free convection melt values far exceed those for laminar forced convection. At the low flow velocities, the melting flux was not dependent upon the fluid temperature until the water temperature dropped below 3.4 C, when q sub c = 135.7 (Delta T). In general, the heat transfer was found to significantly exceed that of non-melting systems for the same regimes. This was attributed to increased free stream turbulence, thermal instability due to the density maximum of water near 4 C, and the turbulent eddies associated with the generation of a wavy ice surface during the melting.
    Type of Medium: Series available for loan
    Pages: vii, 85 Seiten , Illustrationen
    Series Statement: CRREL Report 86-3
    URL: https://apps.dtic.mil/docs/citations/ADA170427
    URL: https://erdc-library.erdc.dren.mil/jspui/bitstream/11681/9438/1/CR-86-3.pdf
    Language: English
    Note: CONTENTS Abstract Preface Nomenclature Introduction Non-melting heat transfer relations for horizontal surfaces Heat transfer for melting horizontal ice sheets Instrument setup, data acquisition and test procedures General Instrumentation Data acquisition Computer software Test procedures Data output from computer Equations used for data analysis Control volume and melting surface Control of variables Error analysis Experimental results and discussion Wave formation Temperature and velocity profiles in open channel flow Correlation of data Summary Literature cited Appendix A: Conversion equations for data acquisition equipment Appendix B: Computer code for data acquisition and analysis Appendix C: Typical test output Appendix D: Thermal properties of water and ice Appendix E: Error analysis Appendix F: Summary of test conditions Appendix G: Experimental data and calculated quantities, with inlet length
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    Short-pulse radar investigations of freshwater ice sheets and brash ice (1986)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-86/6
    In: CRREL Report, 86-6
    Description / Table of Contents: Short-pulse radar profiles and waveform traces were recorded over natural, freshwater ice sheets and an artificially made, 1.6-m-diameter column of brash ice. The purpose was to study the feasibility of this type of radar to detect ice thickness, determine ice properties and distinguish ice forms. The radar utilized two antennas: one with a spectrum centered near 900 MHz and a second more powerful one near 700 MHz. Distinct top and bottom reflections from several ice sheets were produced by both antennas, but the value of dielectric permittivity calculated from the time of delay of the reflections varied between sheets as one ice sheet was ready to candle and contained free water. The brash ice distorted signals and allowed no discernible bottom return. The lower frequency antenna also gave returns from the lake bottom (separated from the ice bottom by about 1 m of water), which could allow ice thickness to be determined indirectly. The report concludes that these antennas can be used to determine sheet ice thickness and to supply information to help in the detection of brash ice. The water content of an ice sheet may also be estimated if independent studies show a correlation between dielectric permittivity and free water content.
    Type of Medium: Series available for loan
    Pages: iv, 15 Seiten , Illustrationen
    Series Statement: CRREL Report 86-6
    URL: https://apps.dtic.mil/docs/citations/ADA172578
    URL: https://hdl.handle.net/11681/9429
    Language: English
    Note: CONTENTS Abstract Preface Introduction Materials and methods Sites and site preparation Results and discussion Lake Morey Post Pond Conclusions and recommendations Literature cited
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    Nitrogen control in wastewater treatment systems for military facilities in cold regions (1986)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-86/7
    In: CRREL Report, 86-7
    Description / Table of Contents: Nitrogen control in the form of ammonia removal or conversion is required, or will be required, for a significant number of military wastewater treatment systems. This reportpresents a summary of engineering criteria for those processes in most common use at military facilities in the cold regions. These processes include: trickling filters, treatmentponds, rotating biological contactors (RBC) and activated sludge. A design example is presented for each case. All four processes can achieve significant levels of ammonia removalor conversion. If ammonia discharge limits are 0.5 mg/L or less it may be necessary to use the activated sludge process. Trickling filters or RBC units are recommended for higher(〉 1 mgIL) discharge limits. Pond systems are suitable for seasonal ammonia removal incold climates.
    Type of Medium: Series available for loan
    Pages: iv, 29 Seiten , Illustrationen
    Series Statement: CRREL Report 86-7
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a173853.pdf
    URL: http://hdl.handle.net/11681/9431
    Language: English
    Note: CONTENTS Abstract Preface Introduction Background and theory Trickling filters Introduction Design procedure Design example Winter operations Pond systems Introduction Design procedure Design example Winter operations Rotating biological contactors Introduction Design procedure Design example Winter operations Activated sludge systems Introduction Design procedure Design example Winter operations Comparison of alternatives Conclusions Literature cited
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  • 21
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    Morphology, hydraulics and sediment transport of an ice-covered river : field techniques and initial data (1986)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-86/11
    In: CRREL Report, 86-11
    Description / Table of Contents: This initial study of the ice-covered Tanana River, near Fairbanks, Alaska, attempted to 1) establish field methods for systematic and repetitive quantitative analyses of an ice-covered river's regime, 2) evaluate the instruments and equipment for sampling, and 3) obtain the initial data of a long-term study of ice cover effects on the morphology, hydraulics and sediment transport of a braided river. A methodology was established, and detailed measurements and samplings, including profiling by geophysical techniques, were conducted along cross sections of the river. A small, portable rotary drill rig equipped with a 356-mm (14-in.) ice auger was used to cut large diameter holes in the ice cover for through-the-ice measurements. Portable heat sources and a heated shelter were required to continuously thaw and dry equipment for the repetitive measurements. Measurements included ice cover thickness, water level, water depth, temperature, flow velocity, suspended load and bed load, frazil ice distribution and bed material composition. Remotely gathered data included apparent resistivity and subsurface radar profiling. The various techniques, sampling gear and problems encountered during use in the subfreezing cold are described in detail in this report.
    Type of Medium: Series available for loan
    Pages: v, 49 Seiten , Illustrationen
    Series Statement: CRREL Report 86-11
    URL: http://hdl.handle.net/11681/9318
    Language: English
    Note: CONTENTS Abstract Preface Introduction Study objectives and field locale Study site Equipment Vehicles Drilling equipment Sampling equipment Geophysical equipment Shelter and icing control Surveying equipment Miscellaneous equipment Field techniques and methodology Logistics Drilling procedures Data collection Geophysical analyses Experiences summary Morphology, transport and hydraulic data Mid-winter physical characteristics Hydraulic characteristics Sediment transport Late winter physical characteristics Seasonal morphology Geophysical data interpretation Spatial morphology Frazil ice characteristics Discussion and conclusions Recommendations Equipment Research Literature cited
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  • 22
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    Natural rotor icing on Mount Washington, New Hampshire (1986)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-86/10
    In: CRREL Report, 86-10
    Description / Table of Contents: Icing of a four-bladed rotor was studied under natural conditions at the top of Mt. Washington, N.H. The rotor had two cylindrical blades and two airfoil blades. The results were compared with studies conducted in icing wind tunnels. Considerable differences in icing regimes were observed. For instance, with comparable liquid water content and wind speed the wet-to-dry growth regime transition temperature was up to 10 C higher under natural conditions than in the wind tunnel studies. Results of other studies made under natural conditions were close to those of the present study, indicating that wind tunnel conditions are significantly different from natural conditions. Close examination of the conditions indicated that supersaturation of water vapor existing in most of the wind tunnel studies is the most probable cause of the differences.
    Type of Medium: Series available for loan
    Pages: v, 68 Seiten , Illustrationen
    Series Statement: CRREL Report 86-10
    URL: http://hdl.handle.net/11681/9328
    Language: English
    Note: CONTENTS Abstract Preface Introduction Site weather Site selection Equipment Rotor Data logger Rotoscope Laser profile camera Thin section preparation Run procedure Sample collection and shutdown Dry runs and static runs Results and discussion Wet-to-dry growth regime transition Stagnation line icing rate Icing rate on cylindrical and airfoil blades Liquid water content vs stagnation line icing rate Droplet capture efficiency index Temperature rise Morphological and crystallographic aspects Summary and conclusion Literature cited Appendix A: Chronology of events .. Appendix B: Narrative description of icing runs Appendix C: Weather summary sheets for test days Appendix D: Signal conditioner circuit diagram and sample printout
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  • 23
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    Evaluation of selected frost-susceptibility test methods (1986)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-86/14
    In: CRREL Report, 86-14
    Description / Table of Contents: Three methods for determining the frost susceptibility of soils are evaluated in this report. These methods are the U.S. Army Corps of Engineers frost design soil classification system, a moisture-tension/hydraulic-conductivity test, and a laboratory freeze-thaw test. The Corps method, which is based on particle size, soil classification, and a laboratory freezing test, was found to be useful for identifying frost-susceptibility. The moisture-hydraulic-conductivity test was found to be unacceptable because it required too much time and its results correlated poorly with field observations. The freeze-thaw test was determined to be the most accurate of the methods studied, including the freeze test that is a part of the Corps method. The freeze-thaw test is thoroughly described. It includes indexes of both frost-heave susceptibility (heave rate) and thaw-weakening susceptibility (CBR after thawing). It also accounts for the effects of freeze-thaw cycling and is completely automated to improve the repeatability of the test results. It is suggested that the freeze-thaw test considered as a replacement for the Corps freezing test.
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    Pages: v, 56 Seiten , Illustrationen
    Series Statement: CRREL Report 86-14
    URL: https://hdl.handle.net/11681/9462
    Language: English
    Note: Contents Abstract Preface Introduction Description of the selected sites Corps of engineers frost design soil classification system Moisture-tension/hydraulic-conductivity tests Freezing test Validation Description of test sites and materials Sample preparation Results and analysis of laboratory tests Corps of engineers frost design soil classification system Moisture-tension/hydraulic-conductivity test Freezing test Discussion Conclusions Recommendations Literature cited Appendix A: Summary of frost-susceptibility tests on natural soil
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    Resilient modulus of freeze-thaw affected granular soils for pavement design and evaluation; Part 3: Laboratory tests on soils from Albany County Airport (1987)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-87/2
    In: CRREL Report, 87-2
    Description / Table of Contents: This is the third in a series of four reports on the laboratory and field testing of a number of road and airfield subgrades, covering the laboratory repeated-load triaxial testing of five soils in the frozen and thawed states and analysis of the resulting resilient modulus measurements. The laboratory testing procedures allow simulation of the gradual increase in stiffnessfound in frost-susceptible soils after thawing. The resilient modulus is expressed in a nonlinear model in terms of the applied stresses, the soil moisture tension level (for unfrozen soil), the unfrozen water content (for frozen soil) and the dry density. The resilient modulus is about 10 GPa for the frozen material at temperatures in the range of -5° to -8° C. The decrease in modulus with increasing temperature was well-modeled in terms of the unfrozen water content. Upon thaw, the modulus dropped to about 100 MPa and generally increased with increasing confining stress and decreased with increasing principal stress ratio. The modulus also increased with the soil moisture tension level. The resilient Poisson's ratio did not appear to be a systematic function of any of the test variables.
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    Pages: iii, 36 Seiten , Illustrationen
    Series Statement: CRREL Report 87-2
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a179253.pdf
    URL: https://hdl.handle.net/11681/9037
    Language: English
    Note: CONTENTS Abstract Preface Introduction Test sections and materials Specimen preparation Test soils Asphalt concrete Laboratory testing Soil testing Waveforms of applied stress Asphalt concrete Data reduction and analysis Soil Asphalt concrete Results and discussion General Resilient modulus Summary Conclusions Literature cited Appendix A: Soil moisture tension versus water content for several test soils Appendix B: Tabulated results for all tests on frozen and thawed soils
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    Frost action predictive techniques for roads and airfields : a comprehensive survey of research findings (1986)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-86/18
    In: CRREL Report, 86-18
    Description / Table of Contents: Findings from a six-year yield and laboratory program of frost action research in four principal areas are summarized. Research on the first topic, frost susceptibility index tests, led to selection of the Corps of Engineers frost design soil classification system as a useful method at the simplest level of testing. At a much more complex level, a new freezing test combined with a CBR test after thawing is recommended as an index of susceptibility to both frost heave and thaw weakening. Under the second topic, a soil column and dual gamma system were developed and applied to obtain soil data used in improving and validating a mathematical model of frost heave, the objective of the third research topic. The model was effectively improved, a probabilistic component was added, and it was successfully tested against field and laboratory measurements of frost heave. A thaw consolidation algorithm was added, which was shown to be useful in predicting the seasonal variation in resilient modulus of granular soils, the objective of the fourth topic. A laboratory testing procedure was developed for assessing the resilient modulus of thawed soil at various stages of the recovery process, as a function of the applied stress and the soil moisture tension, which increases as the soil gradually desaturates during recovery. The procedure was validated by means of appropriate analyses of deflections measured on pavements by a falling-weight deflectometer. Frameworks for implementing findings from the principal research topics are outlined. Keywords: Airfields, Freezing thawing, Frost heave, Frozen soil, Resilient modulus, Roads.
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    Pages: v, 52 Seiten , Illustrationen
    Series Statement: CRREL Report 86-18
    URL: https://apps.dtic.mil/docs/citations/ADA178243
    URL: https://hdl.handle.net/11681/9457
    Language: English
    Note: Contents Abstract Preface Introduction Field test sites Frost-susceptibility index testing Index tests selected Laboratory test results Conclusions Soil column and dual gamma system Design features Test results Mathematical model of frost heave and thaw settlement Model development Numerical approach Probabilistic concepts Model verification Discussion Seasonal variation in the resilient modulus of granular soils Characterization by laboratory testing Field verification Summary of predictive approach Simulating frost heave and pavement deflection Method of evaluation Results and discussion Summary of findings Frost-susceptibility index tests Soil column and dual gamma system Mathematical model of frost heave and thaw settlement Seasonal variation in resilient modulus of granular soils Implementation of research findings Corps of engineers frost design soil classification system New laboratory freeze-thaw test Frost-heave model Repeated-load triaxial test on frozen and thawed soil Evaluation of seasonal variation of resilient modulus Literature cited
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    Mechanical properties of multi-year sea ice : phase 1: ice structure analysis (1987)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-87/3
    In: CRREL Report, 87-3
    Description / Table of Contents: This report describes the structural analysis of multi-year sea ice samples that were tested in the first phase of a program designed to obtain a comprehensive understanding of the mechanical properties of multi-year sea ice from the Alaskan Beaufort Sea. Each test specimen is classified into one of three major ice texture categories: granular, columnar, or a mixture of columnar and granular ice. The crystallographic orientation, percent columnar ice, and grain size are then evaluated for the granular and/or columnar ice in the sample. Test results are interpreted with respect to these parameters. The overall composition of multi-year ridges is also considered, based on the extensive field sampling that was done in the program
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    Pages: iii, 40 Seiten , Illustrationen
    Series Statement: CRREL Report 87-3
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a181205.pdf
    URL: https://hdl.handle.net/11681/9044
    Language: English
    Note: CONTENTS Abstract Preface Introduction Sample analysis Continuous multi-year ridge core Tested multi-year ridge ice samples Tested multi-year floe ice samples Ice description Uniaxial constant-strain-rate compression tests Uniaxial constant-load compression tests Uniaxial constant-strain-rate tension tests Triaxial constant-strain-rate compression test Conclusions Literature cited Appendix A: Multi-year ridge sample data Appendix B: Multi-year floe sample data
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  • 27
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    Crystal structure and salinity of sea ice in Hebron Fiord and vicinity, Labrador (1987)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-87/4
    In: CRREL Report, 87-4
    Description / Table of Contents: In this report we present results of measurements of the crystalline structure and salinity characteristics of sea ice in Hebron Fiord and vicinity, Labrador. Structurally, the fiord ice was entirely first year and composed predominantly of congelation, columnar-type crystals. At most of the sampling sites the ice exhibited moderately to strongly aligned c-axes consistent with the inferred direction of near surface currents in the fiord. Generally diminished values of bulk salinity at five separate locations reflect the warm ice conditions encountered at the time of sampling (late May) and the effect of meltwater flushing in promoting loss of brine, vertically, from the ice sheet. Observations outside Hebron Fiord indicated the presence of only minor amounts of multiyear ice during the latter part of May.
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    Pages: iii, 25 Seiten , Illustrationen
    Series Statement: CRREL Report 87-4
    URL: https://hdl.handle.net/11681/9043
    Language: English
    Note: Contents: Abstract Preface Introduction Sampling procedure Analytical techniques Salinities Crystal structure Results Salinity Crystal structure Brine layer spacing Incidental temperatures Conclusions Literature cited Appendix A: Vertical and horizontal thin section photographs of sea ice from various sites
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  • 28
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    Electromagnetic property trends in sea ice; Part I (1987)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-87/6
    In: CRREL Report, 87-6
    Description / Table of Contents: Two-phase dielectric mixing model results are presented showing the electromagnetic properties of sea ice versus depth. The modeled data are compared with field measurements and show comparable results. It is also shown how the model data can be used in support of impulse radar and airborne electromagnetic(AEM) remote sensing of sea ice. Examples of the remote measurement of sea ice thickness using impulse radar operating in the 80- to 300-MHz frequency band and low-frequency (500 to 30,000 Hz) sounding techniques are presented and discussed. Keywords: Polar regions; Radar pulses.
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    Pages: vii, 55 Seiten , Illustrationen
    Series Statement: CRREL Report 87-6
    URL: https://hdl.handle.net/11681/9041
    Language: English
    Note: Contents Abstract Preface Nomenclature Introduction Sea ice growth and structure Model sea ice Brine salinity Seawater and model brine conductivity Complex dielectric constant of brine Electromagnetic properties of model sea ice at 100 MHz Electromagnetic properties of model sea ice at 100 and 500 MHz and 1 and 5 GHz Example of impulse radar sea ice profiling results Example of frequency-domain electromagnetic sea ice thickness sounding Concluding remarks Literature cited
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    Geochemistry of freezing brines : low-temperature properties of sodium chloride (1987)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-87/13
    In: CRREL Report, 87-13
    Description / Table of Contents: Thermodynamic properties of electrolyte solutions change rapidly below 25C, but these properties are seldom measured over the low temperature range (below 0C), even though some salt solutions can remain unfrozen to -50C. The heat capacities of concentrated solutions (0.5-0.6 molal) of NaC-H2O were measured from 25C to -40C as part of a study to provide thermodynamic data of salt solutions for use in cold regions chemical and geophysical studies. A differential scanning calorimeter was used to measure specific heat capacity from cooling scans as a function of temperature and concentration. The heat capacity data were fit to the equations of Pitzer and coworkers to obtain activity and osmotic coefficients of NaC and H2O, respectively, below o C. Supercooling of the solutions was encouraged by using a fast scan rate (10d2/minute) so that specific heat could be measured to lower temperatures than would be possible if the solutions were allowed to equilibrate with the solid phases. The solubility of ice was calculated and compared to the experiment freezing point of NaC solutions.
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    Pages: ii, 16 Seiten , Illustrationen
    Series Statement: CRREL Report 87-13
    URL: https://apps.dtic.mil/docs/citations/ADA185751
    URL: https://hdl.handle.net/11681/9035
    Language: English
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    Physical and structural characteristics of Weddel Sea pack ice (1987)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-87/14
    In: CRREL Report, 87-14
    Description / Table of Contents: During February and March 1980 the physical properties of Weddell Sea pack ice were investigated via core drilling of 66 floes located along the transect of 600 nautical miles from 64°S to 74°S latitude at roughly 40°W longitude. These studies revealed widespread frazil ice in amounts not known to exist in Arctic sea ice of comparable age and thickness. It is estimated from structure studies of 62 of the 66 floes that 54% of the total ice production of the Weddell Sea is generated as frazil. The disposition and exceptional thickness of the frazil show that mechanisms other than surface turbulence effects are involved and imply that the circulation and structure of the water in the upper levels of the Weddell Sea are significantly different from those in the Arctic basin. Salinities of both first-year and multi-year floes are notably higher than those of their Arctic counterparts because summer surface melting is rare or absent in the Weddell Sea; in the Arctic, downward percolating meltwater flushes through the ice and lowers its salinity. Fluorescence was evaluated as a means of revealing biological activity in Weddell Sea pack ice. It proved useful as an index of combined living and dead material in the ice, but measurements failed to establish any consistent relationship between fluorescence and salinity as suggested be earlier work in the Weddell Sea.
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    Pages: iv, 80 Seiten , Illustrationen
    Series Statement: CRREL Report 87-14
    URL: https://apps.dtic.mil/docs/citations/ADA188189
    URL: https://hdl.handle.net/11681/9036
    Language: English
    Note: CONTENTS Preface Introduction Sea ice structure and classification Logistics and field operations Analytical techniques Crystalline structure Fluorescence Results Salinity Crystalline structure Fluorescence Description of selected floes Conclusions Literature cited Appendix A: Floe descriptions
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    Creep and strength behavior of frozen silt in uniaxial compression (1987)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-87/10
    In: CRREL Report, 87-10
    Description / Table of Contents: Uniaxial constant-stress and constant-strain-rate compression tests were conducted on more than 200 remolded, saturated, frozen specimens of Fairbanks silt under various conditions. A series of curves of stress vs strain rate for various temperatures of strain rates ranging from about 6x10-2 to 10-8s-1show a close strength correspondence between the constant-stress and-costant strain-rate tests. All of these "complete" stress vs strain rate curves could not be described by a single power law or exponential equation, indicating that different deformation mechanisms are dominant within different ranges of strainrate Two critical strain rates for distinguishing between the different deformation mechanisms were ob-served to be near 10- 3 and 10-6 s-1 for the medium-dense frozen Fairbanks silt. The former indicates the transition from ductile failure to moderate brittle fracture as strain rate increases, while the latter indicates the transition from dislocation creep to glide creep (by the authors' definition). Based on the change in flow law, two fundamental creeps were classified: short-term creep, which is governed by glide creep, and long-term creep, which is governed by dislocation creep. The failure criterion of frozen silt has a general form of em x tm = Ef, where m depends only on density, and tm is in minutes if m is not 1. The failure strain Ef was not sensitive to temperature and strain rate over a certain range of strain rates, but it was very sensitive to density. Assur's creep model (1980) for ice was used to fit the creep data in this study. It works well for short-term creep but does not fit as well for long-term creep. The rate process theory was applied to the creep data. A very high value of experimental activation energy was obtained for lower stresses, and a very high value of apparent activation energy was observed for higher temperatures. The peak compressive strength was very sensitive to temperature and strain rate but relatively insensitive to density. While the initial tangent modulus is not-sensitive to strain rate, it increases with decreasing temperature and density.
    Type of Medium: Series available for loan
    Pages: vi, 75 Seiten , Illustrationen
    Series Statement: CRREL Report 87-10
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a184816.pdf
    URL: https://hdl.handle.net/11681/9029
    Language: English
    Note: CONTENTS Abstract Preface Introduction Review of previous work Specimen preparation Material Molding Testing procedure and apparatus Test results Definition of strain and stress Definition of creep failure Definition of failure in constant-strain-rate tests Definition of initial yield strength Determination of initial tangent modulus and 50% peak strength modulus Creep behavior General nature of the creep process and the failure mode Minimum creep rate Time to creep failure Relationship between t, and tm Creep failure strain and failure criterion Creep model and prediction of creep strain Strength behavior General stress-strain behavior and failure mode Peak compressive strength Initial yield strength Failure strain Initial yield strain Initial tangent modulus 50% peak strength modulus Correspondence between constant-stress tests and constant-strain-rate tests Conclusions Literature cited Appendix A: Unfrozen water content data Appendix B: Physical properties of samples tested
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  • 32
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    Thermal instability and heat transfer characteristics in water/ice systems (1987)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-87/22
    In: CRREL Report, 87-22
    Description / Table of Contents: This review discusses problems associated with the anomalous temperature-density relations of water. It covers a) onset of convection, b) temperature structure and natural convective heat transfer, and c) laminar forced convective heat transfer in the water/ice system. The onset of convection in a water/ice system was found to dependent on thermal boundary conditions, not a constant value as in the classical fluids that have a monotonic temperature-density relationship. The water/ice system also exhibits a unique temperature distribution in the melt layer immediately after the critical Rayleigh number is exceeded and soon after it establishes a more or less constant temperature region progressively deepening as the melt layer grows. The constant temperature is approximately 3.2°C for water layers formed from above but varies for melt layers from below. The heat flux across the water/ice interface was found to be a weak power function and to increase linearly with temperature for melted layers from above and below, respectively.
    Type of Medium: Series available for loan
    Pages: vi, 43 Seiten , Illustrationen
    Series Statement: CRREL Report 87-22
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a189627.pdf
    URL: https://hdl.handle.net/11681/9028
    Language: English
    Note: CONTENTS Abstract Preface Nomenclature Introduction Analytical studies on the onset of convection in a horizontal water layer Experimental studies on the onset of convection in a circular horizontal melt layer Temperature structure and heat transfer In a horizontal layer In a circular horizontal melt layer pHeat transfer studies in nonplanar geometries Forced convective heat transfer over a melting surface Discussion and conclusions Onset of convection Temperature structure and natural convective heat transfer Laminar forced convective heat transfer Literature cited
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  • 33
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    Options for management of dynamic ice breakup on the Connecticut River near Windsor, Vermont (1988)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-88/1
    In: CRREL Report, 88-1
    Description / Table of Contents: The Cornish-Windsor bridge is the longest covered bridge in the United States and has significant historical value. At a large peak flow, dynamic ice breakup of the Connecticut River can threaten the bridge and cause flood damage in the town of Windsor, Vermont. Throughout the 1985-86 winter we regularly monitored ice conditions, including a midwinter dynamic ice breakup on 27 January. We conducted controlled release tests over the operating range of the turbines at Wilder Dam upstream during both open water and ice cover conditions. These data and observations were analyzed in light of more than 60 years of temperature and discharge records. Our analysis indicates that river regulation presents alternatives for ice management that would minimize the probability of bridge damage and flooding during breakup. The flow can be regulated early in the winter to promote the growth of a stable ice cover, minimizing the total ice production in the reach. In the weeks prior to breakup, sustained releases and above-freezing air temperatures cause melting, weakening and gradual breakup of the ice, greatly reducing the flooding potential. Also, it is possible to produce a controlled ice breakup prior to an imminent natural event at lower stage and discharge. All of these ice control alternatives have associated power production costs.
    Type of Medium: Series available for loan
    Pages: iii, 21 Seiten , Illustrationen
    Series Statement: CRREL Report 88-1
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a195329.pdf
    URL: https://hdl.handle.net/11681/9026
    Language: English
    Note: CONTENTS Abstract Preface Introduction Background Analysis of historical data Field observations Controlled release tests January 1986 ice breakup Connecticut River ice control Minimizing ice production Hydrothermal melting Controlled ice breakup Conclusions Literature cited Appendix A: Detailed ice breakup chronology
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    Mechanical properties of multi-year sea ice : phase II: ice structure analysis (1988)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-88/5
    In: CRREL Report, 88-5
    Description / Table of Contents: This report describes the structural analysis of multi-year sea ice samples that were tested in the second phase of a program designed to obtain a comprehensive understanding of the mechanical properties of multi-year sea ice from the Alaskan Beaufort Sea. Each test specimen is classified into one of three major ice texture categories: granular, columnar, or a mixture of columnar and granular ice. The crystallographic orientation, percent columnar ice, and grain size are then evaluated for the granular and/or columnar ice in the sample. Test results are interpreted with respect to these parameters. The overall composition of multi-year ridges is considered, based on the extensive field sampling that was done in the program. The effect of sample orientation on the results is also discussed.
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    Pages: iii, 32 Seiten , Illustrationen
    Series Statement: CRREL Report 88-5
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a194980.pdf
    URL: https://hdl.handle.net/11681/9077
    Language: English
    Note: CONTENTS Abstract Preface Introduction Sample analysis Continuous multi-year ridge core Tested multi-year ridge ice samples Unconfined constant-strain-rate compression tests Confined constant-strain-rate compression tests Uniaxial constant-strain-rate tension tests Discussion Conclusion Literature cited Appendix A: Multi-year ridge sample data
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  • 35
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    Freezing of soil with an unfrozen water content and variable thermal properties (1988)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-88/2
    In: CRREL Report, 88-2
    Description / Table of Contents: While many materials undergo phase change at a fixed temperature, soil systems exhibit a definite zone of phase change. The variation of unfrozen water with temperature causes a soil system to freeze of thaw over a finite temperature range. Exact and approximate solutions are given for conduction phase change of plane layers of soil with unfrozen water contents that vary linearly and quadratically with temperature. The temperature and phase change depths were found to vary significantly from those predicted for the constant-temperature or Neumann problem. The thermal conductivity and specific heat of the soil within the mushy zone varied as a function of unfrozen water content. It was found that the effect of specific heat is negligible, while the effect of variable thermal conductivity can be accounted for by a proper choice of thermal properties used in the constant-thermal-property solution.
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    Pages: v, 30 Seiten , Illustrationen
    Series Statement: CRREL Report 88-2
    URL: https://apps.dtic.mil/docs/citations/ADA195343
    URL: https://hdl.handle.net/11681/9076
    Language: English
    Note: CONTENTS Abstract Nomenclature Preface Introduction Basic equations Two-zone problems Linear unfrozen water function Quadratic unfrozen water function Three-zone problems Linear unfrozen water function Quadratic unfrozen water function Conclusions Literature cited Appendix A: Derivation of the mushy zone equation Appendix B: Solution of the two-zone problem with a linear t and variable thermal properties
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    Field tests of the kinetic friction coefficient of sea ice (1985)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-85/17
    In: CRREL Report, 85-17
    Description / Table of Contents: This report presents the results of tests of the ice friction coefficient carried out during the May 1984 expedition of the F.S. Polarstern off the coast of Labrador. The test surfaces were Inerta-160-coated steel plates and bare steel plates, hand roughened and sandblasted. The main findings of the studies were: 1) columnar and granularpea ice showed no significant differences in friction coefficient; 2) for columnar ice was independent of ice crystal orientation with respect to test surface; 3) was Independent of normal pressure applied on ice sample; 4) initially decreased with increasing relative velocity between the Ice sample and the test surface and reached a steady value at higher speeds; 5) Uk increased with increasing surface roughness; 6) a wetting surface exhibited a higher friction coefficient than a non-wetting surface of the same or even higher roughness average.
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    Pages: iv, 26 Seiten , Illustrationen
    Series Statement: CRREL Report 85-17
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a163170.pdf
    URL: https://hdl.handle.net/11681/9413
    Language: English
    Note: CONTENTS Abstract Preface Introduction Test procedure Test apparatus Test surfaces Ice samples Test program Results and discussion Effect of wear of ice sample Effect of normal pressure Effect of velocity, crystal orientation and surface conditions Results summary Comparison with laboratory study Recommendations on test apparatus Literature cited Appendix A : Test results
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  • 37
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    Tensile strength of frozen silt (1987)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-87/15
    In: CRREL Report, 87-15
    Description / Table of Contents: Constant strain-rate tension tests were conducted on remolded saturated frozen Fairbanks silt at various temperatures, strain rates, and densities. It was found that the critical strain rate of the ductile-brittle transition is not temperature-dependent at temperatures down to -5°C, but varies with density. The peak tensile strength decreases considerable with decreasing strain rate for ductile failure, but it decreases slightly with increasing strain rate for brittle fracture. The failure strain remains almost constant at temperatures lower than about -2°C, but it varies with density and strain rate at -5°C. The initial tangent modulus is independent of strain rate and increases with decreasing temperature and density.
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    Pages: v, 29 Seiten , Illustrationen
    Series Statement: CRREL Report 87-15
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a185483.pdf
    URL: https://hdl.handle.net/11681/9033
    Language: English
    Note: CONTENTS Abstract Preface Nomenclature Introduction Testing Material Specimen preparation Testing procedure and apparatus Results Discussion Peak tensile strength, σm Failure tensile strain, ϵf Initial tangent modulus and 50% peak strength modulus Discussion of test techniques Conclusions Literature cited Appendix A: Physical properties of Fairbanks silt specimens Appendix B: Unfrozen water content data of Fairbanks silt with three typical water contents
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    Evaluation of the magnetic induction conductivity method for detecting frazil ice deposits (1987)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-87/17
    In: CRREL Report, 87-17
    Description / Table of Contents: The ability to map frazil ice deposits and water channels beneath an ice-covered river in central Alaska using the magnetic induction conductivity (MI) technique has been assessed. The study was performed during the first week of March of 1986 on the Tanana River near Fairbanks and employed a commercially available instrument operating at a fixed frequency with a fixed antenna (coil) spacing and orientation. Comparisons of the MI data with theoretical models based upon physical data measured along three cross sections of the river demonstrate the sensitivity of the MI technique to frazil ice deposits. The conductivity generally derived for the frazil ice deposits encountered is very low (approx. .00063 s/m) when compared with the measured value for water (approx. 0.011 S/m), and is similar to the calculated values for gravel and sandy gravel bed sediments. In all three cross sections, maxima in the apparent conductivity profiles correlated with frazil ice deposits. Difficulties, possibly due to adverse effects of cold weather upon instrument calibration, affected the quantitative performance of the instrument on one cross section, although the interpretation of the data (locations of open channels vs frazil deposits) was qualitatively unaffected.
    Type of Medium: Series available for loan
    Pages: iii, 17 Seiten , Illustrationen
    Series Statement: CRREL Report 87-17
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a186940.pdf
    URL: https://hdl.handle.net/11681/9023
    Language: English
    Note: CONTENTS Abstract Preface Introduction Magnetic induction conductivity method Site description and survey methods Cross section field data and modeling results X6 X3A X4 Conclusions and recommendations Literature cited Appendix A: Discussion of errors Appendix B: Modeling data
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    Approximate solutions of heat conduction in a medium with variable properties (1987)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-87/19
    In: CRREL Report, 87-19
    Description / Table of Contents: The approximate heat balance integral method (HBIM) is extended to the case of a medium with variable properties such as snow. The case of linear variation of thermal conductivity was investigated. An alternative heat balance integral method (AHBIM) was developed. Both constant surface temperature and surface heat flux were considered. A comparison was made of the temperature distribution from the HBIM, AHBIM and an analytical method for the case of constant surface temperature. In general, results agree quite well with the analytical method for small values of dimensionless time τ, but the difference becomes more pronounced as τ increases. It was found that the AHBIM with a quadratic temperature profile gave a somewhat better result, especially when the value of the dimensionless distance η is small. For a specific property function of E(η) = eη, closed form solutions were obtained. The results, when compared with those from HBIM, AHBIM and the analytical method were found to agree exceptionally well with the analytical method, especially for large values of τ.
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    Pages: iv, 26 Seiten , Illustrationen
    Series Statement: CRREL Report 87-19
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a186933.pdf
    URL: https://hdl.handle.net/11681/9021
    Language: English
    Note: CONTENTS Abstract Preface Nomenclature Introduction Mathematical analysis Constant surface temperature Constant surface heat flux Comparison with exact solution Alternative method Conclusions and comments Literature cited Appendix A: Derivation of equation 25 Appendix B: Derivations of equations 37 and 40 Appendix C: Derivation of equations 37a and 40
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  • 40
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    Dynamic friction of a metal runner on ice : I. Model sled test (1989)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-89/14
    In: CRREL Report, 89-14
    Description / Table of Contents: The effects of runner material and surface conditions on the friction between runners and ice were studied. A model sled was pushed over a 6-m-long ice sheet and the reduction of speed of the sliding sled was measured. The friction calculated by the reduction of speed between two gates indicated that smooth runners showed lower friction at around -1°C than at around -10°C, as expected, but the friction of rough runners showed little temperature dependence. The lower thermally conductive runners showed lower friction than higher thermally conductive smooth runners as the theory predicted, but such effects were obscured on rougher runners.
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    Pages: iii, 23 Seiten , Illustrationen
    Series Statement: CRREL Report 89-14
    URL: https://apps.dtic.mil/docs/citations/ADA211498
    URL: https://hdl.handle.net/11681/9087
    Language: English
    Note: CONTENTS Preface Introduction Apparatus and procedures General approach Sled design Sled propulsion Ice sheet preparation Experimental procedure Results General remarks Effect of runner temperature Effect of runner surface Effect of ice surface conditions Effect of velocity Effect of runner materials Observations of replicate surfaces Statistical analysis Discussion Molecular interactions Mechanical deformations Thermal energy dissipation Hydrodynamidc processes Comparison of energy loss mechanisms Summary and conclusions Literature cited
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    Development of an airborne sea ice thickness measurement system and field test results (1989)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-89/19
    In: CRREL Report, 89-19
    Description / Table of Contents: Recent efforts to improve airborne electromagnetic induction- measurement technology and to downsize the related helicopter-towed antenna assembly from about 7.5 m long to about 3.5 m long for use in airborne measurement of sea ice thickness are discussed, as are the results from arctic field testing. Also outlined are the system noise and drift problems encountered during arctic field evaluation, problems that adversely affected the quality of the sounding data. The sea ice sounding results indicate that it should be possible to determine thickness to within 5% for ice floes with moderate relief but that, because of sounding footprint size and current model algorithm constraints, steepsided pressure ridge keels cannot be well defined. The findings also indicate that routine sea ice thickness profiling from an airborne platform is close at hand with further system improvement, as is the apparent capability to determine the conductivity of the sea ice, from which an assessment of sea ice strength can be made.
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    Pages: iii, 54 Seiten , Illustrationen
    Series Statement: CRREL Report 89-19
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a224867.pdf
    URL: https://hdl.handle.net/11681/9083
    Language: English
    Note: CONTENTS Abstract Preface Introduction Pre-field-deployment activities Software development System optimization Improvements of the calibration procedure Real-time processing Small bird design and implementation Other improvements Field activities Snow, ice and seawater data AEM surveys Calibration AEM data processing Post-survey results Processing problem Ground truth data Floe freeboard vs thickness analysis AEM sounding results Concluding remarks Literature cited Appendix A: Blowup of Figure 28
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    Airfields on Antarctic glacier ice (1989)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-89/21
    In: CRREL Report, 89-21
    Description / Table of Contents: The physical characteristics of blue ice ablation areas in Antarctica are described and some representative ablation rates are given. The possibilities for using blue-ice areas as airfields are outlined and exploratory surveys are mentioned. Site details are given for icefields at Mount Howe, Mill Glacier, Patriot Hills, Rosser Ridge, Mount Lechner, S1 near Casey station, and on the Ross Ice Shelf near McMurdo station. The surface roughness of blue ice is discussed, microrelief surveys are presented for Mount Howe and Patriot Hills, and spectral analyses are used to develop relations between bump height and wavelength. U.S. military specifications for the roughness limits of various types of runways are summarized and graphical comparisons are made with the roughness analyses for Mount Howe and Patriot Hills. Special machines for smoothing ice runways are discussed and design specifications are developed. Some notes on ground facilities and ground transport are included. Appendices give discussions of weather patterns in the Transantarctic Mountains and methodology for making spectral analyses of surface roughness. It is concluded that glacier-ice airfields for conventional transport aircraft can be developed at low cost in Antarctica. Recommendations for further work are offered.
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    Pages: v, 105 Seiten , Illustrationen
    Series Statement: CRREL Report 89-21
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a217638.pdf
    URL: https://hdl.handle.net/11681/9085
    Language: English
    Note: CONTENTS Abstract Preface Introduction Blue-ice areas Blue-ice areas as airfield sites The formation of blue-ice areas Ablation rates at blue-ice areas Exploratory surveys at blue-ice areas Mount Howe Mill Glacier / Plunket Point Patriot Hills Rosser Ridge Mount Lechner The S-1 site near Casey station The McMurdo "Pegasus Site" Surface roughness of blue ice Analysis and characterization of surface roughness Surface preparation to reduce ice roughness Ground facilities Ground transport Conclusions and recommendations Literature cited and selected references Appendix A: Survey data for Patriot Hills, Mount Howe and Mill Glacier Appendix B: Analysis of surface roughness at blue-ice sites Appendix C: Meteorological conditions to be expected in summer in the Trans-antarctic Mountains
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    Level ice breaking by a simple wedge (1985)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-85/22
    In: CRREL Report, 85-22
    Description / Table of Contents: Tests in level ice on an idealized icebreaker bow in the shape of a simple wedge were conducted in the test basin. The horizontal and vertical forces on the wedge were measured, and floe size distribution in the wake of the wedge was observed. From the force measurements, the ice wedge/hull friction factor was calculated and found to be in general agreement with the friction factor measured in separate friction tests. The ice floe length and ice floe area measured in the current study were found to follow log-normal probability distributions defined by the length average L and area average A and corresponding standard deviations SL and SA. The results of these tests and other tests conducted at another facility showed that the ratios A/h2 and L/h (A =average floe area, L averagefloe length, h = ice thickness) were, for the same type of model ice, directly proportional to the parameter y/-yh. (a = ice bending strength, tj7= specific weight of water) and a/y, respectively, and independent of the velocity and ice strain modulus or ice characteristic* length. However, the coefficients of proportionality appear to depend upon the type of model ice used in the tests. The ratios Si/A were independent of o/yh but varied with the bow shape and the type of ice. The available field data are not sufficient for meaningful comparison with the laboratory results.
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    Pages: iv, 53 Seiten , Illustrationen
    Series Statement: CRREL Report 85-22
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a166629.pdf
    URL: https://hdl.handle.net/11681/9443
    Language: English
    Note: CONTENTS Abstract Preface Introduction Experimental set-up and conditions Results of wedge resistance measurements Results of floe size measurements Statistical analysis of data Comparison between model and full-scale data Conclusions and recommendations Literature cited Appendix A: Wedge tests-floe size measurements Appendix B: Wedge tests-histograms of floe length and floe area Appendix C: Cumulative frequency distributions for floe length and floe area
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    Atmospheric icing on communication masts in New England (1986)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-86/17
    In: CRREL Report, 86-17
    Description / Table of Contents: Rime icing and freezing precipitation are of concern to the radio and television broadcasting industry. This report contains the results of a study seeking to document the severity and extent of transmitter tower icing and related problems in the northeastern United States. Information was obtained via mail questionnaire and telephone interviews with 85 station owners and engineers concerning 118 different stations. Results show that television and FM broadcasters are seriously impacted by tower icing; however, AM operators are usually not affected by expected New England icing levels. Combined annual costs for icing protection and icing-related repairs averaged $121, $402 and $3066 for AM, FM and TV stations respectively. None of the AM stations polled employ any icing protection in the three northern states averaged 80%, indicating a significant concern for icing in that region. In contrast, the percentage of FM stations with icing protection was 63.5% for the southern New England states. The usage of guyed versus non-guyed towers was a poor indicator of icing costs. However, the factors of increasing mast height and mast top elevation are significant to increasing costs.
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    Pages: iv, 52 Seiten , Illustrationen
    Series Statement: CRREL Report 86-17
    URL: https://hdl.handle.net/11681/9459
    Language: English
    Note: Contents Abstract Preface Introduction Background Types of accretions Problems caused by icing Prevention and shedding methods Results The survey Data presentation Discussion Survey response distribution Effect of icing protection on parameter averages Effect of tower type on parameter averages Moderate and more severe icing locations Relationship of climate, geography and topography to icing severity Total annual costs Conclusions Literature cited Appendix A: Tower icing survey Appendix B: Station summaries
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  • 45
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    Numerical modeling of sea ice dynamics and ice thickness characteristics : a final report (1985)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-85/5
    In: CRREL Report, 85-5
    Description / Table of Contents: A dynamic-thermodynamic sea ice model is extended to include a full thermodynamic code and a complete multilevel ice thickness distribution. The variable thickness formulation includes a more realistic parameterization of ice ridging than used in previous models. Seasonal simulations have been performed using this model and the results have been analyzed with particular emphasis on examination of the ridge buildup results off the Canadian Archipelago and off the North Slope. This report presents a complete description of this model and discusses progress made on examining and testing the variable thickness extensions.
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    Pages: vi, 60 Seiten , Illustrationen
    Series Statement: CRREL Report 85-5
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a154600.pdf
    URL: https://hdl.handle.net/11681/9354
    Language: English
    Note: CONTENTS Abstract Preface Summary Introduction Description of the model Ice thickness equations Heat budget and oceanic boundary layer Analytic examination of the ridge redistribution process Theoretical framework Some specific redistributors Comparison to ridge morphological data Ice strength for different redistributors Numerical simulation results Basin-wide ice thickness and velocity characteristics Ice edge evolution and sensitivity Ice thickness characteristics off the Canadian Archipelago Comparison of observed and simulated ice drift Mass balance characteristics Concluding remarks Literature cited Appendix A: Mechanical redistributor Appendix B: Heat budget code Appendix C: Thickness finite difference code
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  • 46
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    Review of methods for generating synthetic seismograms (1985)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-85/10
    In: CRREL Report, 85-10
    Description / Table of Contents: Various methods of generating synthetic seismograms are reviewed and examples of recent applicatiors of the methods are cited. Body waves, surface waves, and normal modes are considered. The analytical methods reviewed include geometric ray theory, generalized ray theory (Cagniard-de Hoop method), asymptotic ray theory, reflectivity method, fullwave theory, and hybrid methods combining ray theory and mode theory. Two numerical methods, those of finite differences and finite elements, and a hybrid method combining finite differences with asymptotic ray theory are described Limitations on the application or validity of the various methods are stated.
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    Pages: v, 48 Seiten , Illustrationen
    Series Statement: CRREL Report 85-10
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a159128.pdf
    URL: https://hdl.handle.net/11681/9398
    Language: English
    Note: CONTENTS Abstract Preface Nomenclature Section 1. Introduction Section 2. Wave propagation in the earth Section 3. Body waves: ray theory and wave theory Geometric ray theory Wave theory Section 4. Surface waves Section 5. Normal modes Section 6. Finite-difference method Section 7. Finite-element method Section 8. Hybrid methods Section 9. Conclusion Literature cited
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  • 47
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    Thermal convection in snow (1985)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-85/9
    In: CRREL Report, 85-9
    Description / Table of Contents: Large temperature gradients applied to a snow cover drive water vapor upwards and result in rapid recrystallization of snow crystals. The same temperature gradients create gradients of air density that can cause flows of air through the snow cover. The formalism necessary to describe these flows I developed heroin an effort to include the convection of vapor in the understanding of snow metamorphism. The theory of convection through porous media is extended here to include the transport of water vapor, which is important because of its latent heat. Results are presented in terms of a Lewis number, defined as the ratio of thermal to mass diffusivities. For Lewis numbers greater than 1.0 phase change intensifies convection, and for Lewis numbers less than 1.0 phase change retards convection. Two boundary conditions of special interest in the study of snow, a constant heat flux bottom and a permeable top are investigated. Their influence on the transfer of heat is quantified, and it is found that heat transfer can be described as a linear function of the driving force for convection. Convection in sloped layers is quantified, and explained in a physically consistent manner. The effect of a permeable top on convection at low Rayleigh numbers is derived. Experiments are performed to measure the effects of convection on heat transfer through glass beads and snow. The model results using constant flux boundary conditions are confirmed by the experiments. Experiments show that convection can occur in snow, and that convection behaves in a manner consistent with our theoretical understanding of the phenomenon. Some uncertainty exists about the permeability and thermal conductivity of snow and hence it is uncertain if thermal convection would occur for a given temperature gradient, density and thickness. Also, for a given convective intensity, there is much uncertainty about how much the rate of snow metamorphism is increased.
    Type of Medium: Series available for loan
    Pages: vi, 70 Seiten , Illustrationen
    Series Statement: CRREL Report 85-9
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a157577.pdf
    URL: https://hdl.handle.net/11681/9395
    Language: English
    Note: CONTENTS Abstract Preface Nomenclature Introduction Snow metamorphism Mass transfer by diffusion in snow Heat transfer Background-porous media Structure of thermal convection Rayleigh number Onset problem Heat transfer attributable to thermal convection Layering and slope effects Studies of convection through snow Modeling Equation of motion Energy equation Finite difference methods Numerical solution Verification of the model Modeling results Effects of constant flux and permeable boundaries on convection in horizontal layers Effects of phase change on convection Convection in sloped layers Experiments Introduction Experimental apparatus Experimental results and discussion Glass beads Snow Applications and conclusions Onset of Benard convection in seasonal snow covers Applications to snow metamorphism Summary Recommendations Literature cited Appendix A: Derivation of fmite difference formulae Appendix B: Computer programs Appendix C: Sample calculations
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  • 48
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    TNT, RDX and HMX explosives in soils and sediments : analysis techniques and drying losses (1985)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-85/15
    In: CRREL Report, 85-15
    Description / Table of Contents: A method for the analysis of TNT, RDX and HMX explosives in soils and sediments has been developed. It consists of methanol extraction followed by reversed-phase high performance liquid chromatography using 10% acetonitrile/40% methanol/50% water as the eluant. This method was used to study the effect of various drying techniques upon the recovery of TNT, RDX, and HMX from soil and sediment samples contaminated with high (%) and low (micron g/g) levels of these explosives. For highly contaminated samples, complete recovery of TNT and RDX was obtained using freeze drying while air drying at room temperature resulted in greater than 90% recovery for both explosives. Other techniques, such as oven drying at 105 C, oven drying at 45 C, microwave oven drying, and drying under infrared lamps, all resulted in greater losses, with TNT and RDX recoveries ranging from 76 to 90%. Drying losses were not due to simple volatilization containing low levels of TNT, RDX and HMX, recoveries of all three explosives were quantitative for all the above drying techniques.
    Type of Medium: Series available for loan
    Pages: iii, 15 Seiten , Illustrationen
    Series Statement: CRREL Report 85-15
    URL: https://apps.dtic.mil/docs/citations/ADA163278
    URL: https://hdl.handle.net/11681/9417
    Language: English
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  • 49
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    Mechanical properties of multi-year sea ice : phase II: test results (1985)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-85/16
    In: CRREL Report, 85-16
    Description / Table of Contents: This report presents the results of the second phase of a test program designed to obtain a comprehensive understanding of the mechanical properties of multi-year sea ice from the Alaskan Beaufort Sea. In Phase 2, 62 constant-strain-rate uniaxial compression tests were performed on horizontal and vertical ice samples from multi-year pressure ridges to examine the effect of sample orientation on ice strength. Also conducted were 36 constant-strain-rate tension tests, 55 conventional triaxial tests and 35 constant-load compression tests on multi-year pressure ridge samples to provide data for developing ice yield criteria and constitutive laws. Data are presented on the strength, failure strain and modulus of multi-year sea ice under different loading conditions. The effects of ice temperature, porosity, structure, strain rate, confining pressure and sample orientation on the mechanical properties of multi-year sea ice are examined.
    Type of Medium: Series available for loan
    Pages: vi, 89 Seiten , Illustrationen
    Series Statement: CRREL Report 85-16
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a166333.pdf
    URL: https://hdl.handle.net/11681/9414
    Language: English
    Note: CONTENTS Abstract Preface Introduction Field sampling program Site selection and description Coring procedures Core logging procedures Shipping and storage of ice samples Ice description Salinity and density Structure Constant-strain-rate compression tests Test variables Uniaxial compressive strength Strength and structure Strength and porosity Residual compressive strength Failure strain Initial tangent modulus Constant-strain-rate uniaxial tension tests Test variables Uniaxial tensile strength Failure strains Initial tangent modulus Constant-strain-rate triaxial tests Equipment Test variables Synthane end caps Triaxial strength Failure strains Initial tangent modulus Effect of sinthane end caps on results Constant-load compression tests Test variables Test results Conclusions Literature cited Appendix A: Ice structure profile of ridge C core Appendix H: Test data Appendix C: Static determination of Young's modulus in sea ice
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  • 50
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    Sorption of military explosive contaminants on bentonite drilling muds (1985)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-85/18
    In: CRREL Report, 85-18
    Description / Table of Contents: Concern over the environmental fate of explosives has brought about the development of sensitive analytical methods for measuring them in groundwater. In turn this concern has been extended to validating the sampling procedures for groundwater. This report addresses the potential effects of residual drilling muds on the analysis for explosive contaminants (TNT, DNT, RDX, and HMX) in monitoring wells. The approach was to determine sorption isotherms for each contaminant. Sorption appeared to be independent of solids concentration. Linear isotherms were obtained for RDX and HMX over a range of analytic concentrations; therefore, a single constant can be used to estimate the amount sorbed when the solution concentration is known. Isotherms for TNT and DNT were not linear, however. Scatchard analysis suggested that the isotherms for these analytes could be resolved into two predominant components: a linear component above a certain sorbed quantity and a Langmuir-type component below this quantity. The experimental data were fitted by regression analysis using the appropriate model. The equations developed can be used to predict the sorbed fraction (analytical bias) for any combination of solids and analyte concentration. The amounts of bentonite found in some existing wells do not appear to be sufficient to cause significant bias in analyses for these explosive contaminants.
    Type of Medium: Series available for loan
    Pages: iv, 40 Seiten , Illustrationen
    Series Statement: CRREL Report 85-18
    URL: https://apps.dtic.mil/docs/citations/ADA163231
    URL: https://hdl.handle.net/11681/9305
    Language: English
    Note: CONTENTS Abstract Preface Introduction Materials and methods Bentonite and water samples Sorbate solutions Sorption isotherms HPLC analysis Analyte standards Water solubilities Octanol-water partition coefficients Sorption isotherms Freundlich Langmuir BET Scatchard Gibbs Linear Polynomial Results and discussion TNT DNT RDX and HMX Effect of drilling muds on analysis SEM and EDXA analysis of bentonite wells Other studies Summary Literature cited Appendix A : Results for TNT Appendix B: Results for DNT Appendix C: Results for RDX Appendix D : Results for HMX Appendix E: Characteristics of Quik-Gel, Aqua-Gel and well water
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  • 51
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    Microwave and structural properties of saline ice (1987)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-87/20
    In: CRREL Report, 87-20
    Description / Table of Contents: The structure and salinity characteristics of saline ice slabs removed from ice sheets grown in an outdoor pool have been studied and related to the complex relative dielectric permittivity measured with free-space transmission techniques at 4.80 and 9.50 GHz. The saline ice closely simulated arctic sea ice in its structural and salinity characteristics, which were regularly monitored in a number of ice sheets grown during the winters of 1983-84 and 1984-85. In-situ transmission measurements at similar frequencies were also made on the ice sheets themselves using antennas located above and beneath the ice. The slab measurements were made during warming from -29° to -2°C on slabs grown during the winter of 1983-84 (4.75 GHz) and during a warming and cooling cycle over a slightly larger temperature range on slabs grown during the winter of 1984-85 (4.80 and 9.50 GHz).
    Type of Medium: Series available for loan
    Pages: v, 41 Seiten , Illustrationen
    Series Statement: CRREL Report 87-20
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a189307.pdf
    URL: https://hdl.handle.net/11681/9022
    Language: English
    Note: CONTENTS Abstract Preface Part I - Structural properties Introduction Experimental setup Analytical techniques Results and discussion 1983-84 experiments 1984-85 experiments Conclusions and recommendations Part Il - Microwave properties Introduction Measurement techniques Results 1983-84 experiments 1984-85 experiments 1984-85 in-situ experiments Discussion Comparison of data Analytical modeling Summary and conclusions Literature cited Appendix A: Dielectric mixing model of sea ice
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  • 52
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    Spectral measurements in a disturbed boundary layer over snow (1987)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-87/21
    In: CRREL Report, 87-21
    Description / Table of Contents: The author measured time series of longitudinal (u) and vertical (w) velocity and temperature (t) and humidity (q) fluctuations with fast-responding sensors in the near-neutrally stable surface layer over a snow-covered field. These series yielded individual spectra and u-w, w-t, w-q and t-q cospectra, phase spectra and coherence spectra for nondimensional frequencies (fz/U) from roughly 0.001 to 10. With the exception of the u-w cospectra, all the spectra and cospectra displayed the expected dependence on frequency in an inertial or inertial-convective subrange. All, however, contained significantly more energy at low frequency than the Kansas neutral-stability spectra and cospectra. This excess low-frequency energy and the erratic behavior of the u-w cospectra imply that forested hills bordering the site on two sides were producing disturbances in the flow field at scales roughly equal to the height of the hills, 100 m. The phase and coherence spectra suggest that internal gravity waves were also frequently present, since the atmospheric boundary layer generally had slightly stable stratification. Consequently, at this complex site, turbulence alone determines the spectra and cospectra at high frequency; at low frequency the spectra and cospectra reflect a combination of topographically generated turbulence and internal waves. From the measured temperature and humidity spectra and the t-q cospectra, the author computed refractive index spectra for light of 0.55-micrometer and millimeter wavelengths. The refractive index spectra had shapes like the other scalar spectra: excess energy at low frequency and an inertial-convective subrange at high frequency.
    Type of Medium: Series available for loan
    Pages: v, 50 Seiten , Illustrationen
    Series Statement: CRREL Report 87-21
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a190217.pdf
    URL: https://hdl.handle.net/11681/9027
    Language: English
    Note: CONTENTS Abstract Preface Introduction Measurements Spectra u and w velocity spectra Temperature and humidity spectra Inertial-dissipation estimates Cospectra u-w cospectra w-t and w-q cospectra t-q cospectra Refractive index spectra Conclusions Literature cited
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  • 53
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    The chemical and structural properties of sea ice in the southern Beaufort Sea (1989)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-89/25
    In: CRREL Report, 89-25
    Description / Table of Contents: This study provides a detailed chemical and structural profile of first-year and multiyear Arctic sea ice. Ice cores were collected during April- May 1986 and 1987 near Prudhoe Bay, Alaska. Concentrations of Cl, Br, SO4, Na, Ca, K, Mg, PO4, SiO4, NO3, NO2 and NH4 were determined for samples chosen on the basis of structural ice type. Chemical and statistical analyses indicate that finer-grained structures incorporate more impurities and that major ion chemistry is controlled almost entirely by salinity. Mg is enriched in the ice indicating precipitation is occurring at temperatures higher than previously reported. K is depleted in the ice suggesting preferrential drainage. Ratios of the major ions are the same for first-year and multiyear ice and are similar to that of seawater indicating that as the ice ages no significant changes occur in ice chemistry. Nutrient concentrations in the ice are enriched with respect to the underlying water, indicating that biological activity occurs in the ice and processes other than the overall salinity effect and brine drainage are affecting nutrient concentrations within the ice.
    Type of Medium: Series available for loan
    Pages: vi, 144 Seiten , Illustrationen
    Series Statement: CRREL Report 89-25
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a219746.pdf
    URL: https://hdl.handle.net/11681/9097
    Language: English
    Note: CONTENTS Abstract Preface Introduction Background Formation, growth, and structure of sea ice Oceanic frazil production Multiyear ice Equilibrium growth Summer ice decay Annual layering Salinity distribution in sea ice Chemistry of sea ice Study area description Objectives Methodology Sample collection Blanks Chemical analyses Thin sections Data reduction Results and discussion First-year ice Multiyear ice Comparison of first-year and multiyear ice Summary Conclusions Future work References Appendix A: Concentration of chemical species in sea ice as reported in the literature Appendix B: Ice and water data Appendix C: Linear regression data
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