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  • Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory  (201)
  • English  (201)
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  • 2015-2019
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  • 1
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    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-94/5
    In: CRREL Report, 94-5
    Description / Table of Contents: A three-dimensional theory is derived to describe the temporal behavior of gravity currents of cohesionless granular media, in an attempt to model the motion of dense, flow-type snow avalanches, ice and rock slides. A mohr-Coulomb yield criterion is assumed to describe the constitutive behavior of the material, and the basal bed friction is described similarly by a Coulomb type of friction. A drag term is included in order to model the occurrence of flow regimes where boundary drag becomes non-negligible. Data from laboratory simulations are compared to a series of numerical studies based on the aforementioned theory. A nondimensional, depth and width averaged form of the theory is considered. A Lagrangian finite difference scheme is then applied to numerically model some limiting cases of the governing equations. Two different numerical models are developed, tested and compared to experimental values. The results indicate that the model can account for flow transitions by inclusion of the drag term when the initial inclination angle is large enough to affect boundary drag. Furthermore, the temporal and spatial evolution of the granulate and final runout position can be predicted to values well within the experimental error.
    Type of Medium: Series available for loan
    Pages: iv, 29 Seiten , Illustrationen
    Series Statement: CRREL Report 94-5
    Language: English
    Note: CONTENTS Preface Nomenclature Introduction Mathematical formulation Limiting cases of the governing equations Nondimensionalization scheme Numerical solutions and comparison to experiments Unconstrained Coulomb flow model with constant bed friction Unconstrained Coulomb flow with boundary drag term Conclusions and remarks Literature cited Abstract
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  • 2
    Call number: ZSP-201-94/12
    In: CRREL Report, 94-12
    Description / Table of Contents: Subsurface radar was used to profile ice and snow conditions on the Ross Ice Shelf at McMurdo Station, Antarctica, during mid-January 1993. Deconvolution and migration were often used to improve vertical resolution and spatial imaging. Profiles at a pulse center frequency of 400 MHz along the 3.2-km-long Pegasus ice runway show many low-density horizons above 9 m depth that are up to 30 m long. They are associated with air bubbles included during refreezing of meltwater and are interpreted as layers between a few and tens of centimeters thick. There is a strong reflecting horizon at about 9 m depth that is probably from brine intrusion as it is continuous with the intrusion into the snow to the east. Diffraction asymptotes give a dielectric constant near 3.2 for material above the brine level, a value that implies near-solid ice. Profiles at 100 MHz along the road between Pegasus runway and Williams Field in the accumulation zone show snow features such as layer deformation and intrusive brine layers that both abruptly and gradually change in depth. A single profile at a relic solid waste dump at Williams Field detected buried debris and ice within the upper 7 m. A survey of a suspected fuel spill shows some local disturbances near the center, but no excavation was done to verify the findings. Profiles traversing the sewage sumps at Williams Field outline the extent of the sewage deposition, and give depths to contaminated snow that closely agree with observation. Despite variability in dielectric properties, single-layer migration effectively improves the resolution of subsurface conditions. Recommendations are made for future surveys.
    Type of Medium: Series available for loan
    Pages: iv, 29 Seiten , Illustrationen
    Series Statement: CRREL Report 94-12
    Language: English
    Note: CONTENTS Preface Introduction Radar equipment General operation Antennas Waveforms and phase polarity Antenna directivity Field procedures and data processing Field procedures Data recording Data processing Site location Results Pegasus runway Access road from Williams Field to Pegasus runway Williams Field Summary and conclusions Literature cited Appendix A: Airborne profile of a portion of the access road Abstract
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  • 3
    Call number: ZSP-201-93/11
    In: CRREL Report, 93-11
    Description / Table of Contents: A laboratory study of the behavior of snow under shock wave loading and unloading conditions was conducted using a 200-mm-diameter gas gun to generate loading waves in snow samples with initial densities of 100 to 520 kg m-3 at temperatures of -2 to -23 deg C. Stress levels were 2 to 40 MPa. The response of snow to shock wave loading was measured as a function of distance from the impact plane using embedded stress gauges. Large impedance differences between snow and the stress gauges produced complex stress histories. A finite element model, along with a simple analytical model of the experiment, was used to interpret the stress histories. Snow deformation was not affected by initial temperature, but was found to be rate dependent. The initial density of the snow determined its pressure-deformation path. The pressure needed to compact snow to a specific final density increases with decreasing initial density. The release moduli increased nonlinearly from 50 MPa at a snow pressure of about 15 MPa to 2700 MPa at a snow pressure of about 40 MPa.
    Type of Medium: Series available for loan
    Pages: iii, 150 Seiten , Illustrationen
    Series Statement: CRREL Report 93-11
    Language: English
    Note: CONTENTS Preface Introduction Experimental equipment and methods Gas gun Snow target assembly Data acquisition Experimental procedure Measured data Stress histories Snow characterization Data analysis Recommendations Experimental methods Experimental needs Summary Literature cited Appendix A : Stress-time data plots Appendix B: Tabulated stress-time data Abstract
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  • 4
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    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-93/9
    In: CRREL Report, 93-9
    Description / Table of Contents: Traction on winter surfaces was measured using three test vehicles, each designed to measure traction for a different purpose: vehicle mobility research (CRREL Instrumented Vehicle), commercial tire testing (Uniroyal- Goodrich traction tester), and airport runway safety (Saab friction tester). The traction measured with each method is comparable, but there are systematic differences due to the effects of the surface material and the test and analysis technique. This comparison serves as the fundamental basis for collaboration between the various traction testing communities and illustrates the need for well documented test procedures and data analysis as a standard for traction testing and evaluation.
    Type of Medium: Series available for loan
    Pages: iii, 21 Seiten , Illustrationen
    Series Statement: CRREL Report 93-9
    Language: English
    Note: CONTENTS Preface Introduction Traction test methods Saab friction tester Uniroyal-Goodrich traction tester CRREL Instrumented Vehicle Surfaces tested Reporting results and terminology Factors influencing traction Results Traction curves for each surface Traction coefficients Conclusion Literature cited Appendix A: Vehicle instrumentation and samples of graphic output Appendix B: Comparison of measured traction coefficients with published andpredicted values Abstract
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  • 5
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    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-93/3
    In: CRREL Report, 93-3
    Description / Table of Contents: Results are presented of a study to determine appropriate methods of flow modification for mitigating ice jam formation in navigable rivers. Based on a review of alternative methods for flow modification, it is concluded that for many rivers, especially large ones, the most appropriate method involves controlled ice-cover formation through the regulation of river flow. Flow discharge and stages would be regulated by controlling the flow releases from reservoirs and flow stages at river dams, such that optimal flow conditions prevail for rapid formation, and subsequent maintenance, of an accumulation ice cover over river reaches in which potentially large amounts of frazil ice may grow. Accumulation covers would be formed of frazil ice pans and floes and, if appropriate, broken ice conveyed from upstream. Existing dams, augmented where needed by navigable ice booms, could serve as retention structures for the development of accumulation covers. A preliminary indication of the feasibility of this method for controlling ice-cover formation on stage-regulated pools of the Ohio River is assessed through the use of a numerical model that simulates ice-cover formation from frazil ice. It is found that this approach holds promise for mitigating jam occurrence, although its implementation necessarily entails management of flow through major portions of the Ohio River. The results of the study are, to a limited extent, generalized to other rivers.
    Type of Medium: Series available for loan
    Pages: v, 58 Seiten , Illustrationen
    Series Statement: CRREL Report 93-3
    Language: English
    Note: CONTENTS Preface Nomenclature Introduction Background Scope of the study Control of river ice formation Control methods Controlled ice-cover formation for the upper Ohio River Numerical simulation of ice-cover formation Flow profile Water temperature variation Frazil ice growth Ice-cover progression Thermal growth of ice cover Numerical results Illustration of simulated ice-:over formation Ice-cover formation in the Hannibal and Montgomery pools Generalized results Conclusions and recommendations Literature cited Appendix A: Expression for coefficients Appendix B: Listing of computer program
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  • 6
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    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-92/17
    In: CRREL Report, 92-17
    Description / Table of Contents: The CRREL Instrumented Vehicle (CIV), shear annulus, direct shear, andtriaxial compression devices were used to characterize the strength ofthawed and thawing soil. These strength values can be used in simpletraction models to predict the tractive performance of vehicles. Strength was evaluated in terms of the parameters c' and Φ' based on the Mohr-Coulomb failure criterion. It is proposed here that an instrumented vehicle is best suited for terrain characterization for mobility studies because the conditions created by a tire slipping on a soil surface are exactly duplicated. The c' and Φ' values from the shear annulus were found to overpredict traction because of the low normal stress applied by the annulus and the curved nature of the failure envelope. Of all the tests, the direct shear test yielded the highest Φ' value, most likely because the test was run at a slow deformation rate under drained conditions. The triaxial test results were the most similar to those from the vehicle. All test methods show Φ' increasingwith soil moisture up to the liquid limit of the soil and then decreasing. As measured with the vehicle, was also found to be strongly influenced by the thaw depth.
    Type of Medium: Series available for loan
    Pages: 17 Seiten , Illustrationen
    Series Statement: CRREL Report 92-17
    Language: English
    Note: CONTENTS Introduction Objective Background Strength measurement techniques Triaxial compression Direct shear Shear annulus device CRREL Instrumented Vehicle Discussion Comparison of methods Influence of soil conditions Traction prediction Conclusions References Abstract
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  • 7
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    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-92/14
    In: CRREL Report, 92-14
    Description / Table of Contents: Large ice jams on the Salmon River have reached Salmon, Idaho, and resulted in major flood damage during 16 winters since the winter of 1936-37. Two recent ice jams, in February 1982 and January 1984, caused flooding that resulted in damages of $1 million and $1.8 million respectively. A detailed analysis of the winter air temperature records from 1936-37 through 1991-92 revealed a strong relationship between the duration and intensity of severe cold periods, the air temperature record prior to the severe cold periods, and the occurrence of ice jams reaching the city of Salmon that result in flooding. A threshold condition is identified from which the probability of icejams reaching the city can be determined from inspection of forecasted air temperatures. It was found that once an icejam reaches the city, average daily air temperatures of approximately 18 deg F are necessary to keep the jam in place. The effects of discharge on ice thickness, and therefore ice jam length, are shown to be minor and no relation could be found in this study. An ice control structure located upstream of the city of Salmon appears to be helping to alleviate ice-jam flooding.
    Type of Medium: Series available for loan
    Pages: iv, 18 Seiten , Illustrationen
    Series Statement: CRREL Report 92-14
    Language: English
    Note: CONTENTS Preface Conversion factors Introduction Data sources and analysis Air temperature records Air temperature curves Air temperature record analysis Discharge records Results Phase 1 Phase 2 Phase 3 Effects of discharge Salmon River ice control Conclusions Literature cited Abstract
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  • 8
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    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-91/12
    In: CRREL Report, 91-12
    Description / Table of Contents: Field trials using a man-portable Geonics, Ltd., EM31 electromagnetic induction sounding instrument, with a plug-in data processing module, for the remote measurement of sea ice thickness, are discussed. The processing module was made by Flow Research Inc., to directly measure sea ice thickness and show the result in a numerical display. The EM31-processing module system was capable of estimating ice thickness within 10% of the true value for ice from about 0.7 to 3.5 m thick, the oldest undeformed ice in the study area. However, since seawater under the Arctic pack ice has a relatively uniform conductivity (2.5 + or - 0.05 S/m), a simplified method, which can be used for estimating sea ice thickness using jet an EM31 instrument, is discussed. It uses only the EM31's conductivity measurement, is easy to put into use and does not rely on theoretically derived look-up tables or phasor diagrams, which may not be accurate for the conditions of the area.
    Type of Medium: Series available for loan
    Pages: iv, 23 Seiten , Illustrationen
    Series Statement: CRREL Report 91-12
    Language: English
    Note: CONTENTS Preface Introduction EM 31 Sounding concepts Previous EMI studies Beaufort Sea field trials EM 31 Conductivity reading versus sea ice thickness General comments Literature cited Abstract
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  • 9
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    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-91/5
    In: CRREL Report, 91-5
    Description / Table of Contents: An analysis of the National Science Foundation's surface vehicle fleet in Antarctica is reported on here. Surface vehicle needs have been determined through interviews of vehicle users, managers and maintainers, and from direct on-site observation. An ideal grouping of vehicle categories is proposed that will address current needs and provide flexibility for the future. Ultimately, recommendations for streamlining and modernizing the NSF Antarctic vehicle fleet are made. Cargo transportation over snow was identified as being in a crisis state. Personnel movement functions for all but traversing are performed adequately at this time, although there is much room for improvement. Brands and models must be selected for some categories of recommended vehicle types. This will naturally follow a more in-depth analysis of candidates and discussions with NSF vehicle managers. A purchasing plan, including a time table, budget, and desired sequence of replacement, must then be formulated and executed.
    Type of Medium: Series available for loan
    Pages: v, 71 Seiten , Illustrationen
    Series Statement: CRREL Report 91-5
    Language: English
    Note: CONTENTS Preface Executive summary Introduction Regional divisions Zone A - rock and ice roads Zone B - local ice Zone C - traverse Zone D - ice edge Zone E - remote field site Zone F - inland station Current transportation needs in Antarctica Future transportation needs Transportation analysis Personnel transport Cargo transport Summary of analysis Recommendations for changes to U.S. vehicle fleet Conclusions and summary of findings Literature cited Appendix A: Age distribution of NSF surface vehicles Abstract
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  • 10
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    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-91/15
    In: CRREL Report, 91-15
    Description / Table of Contents: An overview is presented of recent activities and results in the use of commercially available short-pulse UHF radar for surveying ice conditions on freshwater bodies. Improvements in radar systems have made it possible to increase ice thickness resolution by as much as one third relative to that in past attempts, and some new signal processing approaches shown here may offer an order of magnitude improvement. Results from airborne surveying are shown in which the varieties of ice character are reflected. Given the lack of ground coupling, one can rely upon a reasonably well-defined wavelet structure for enhanced signal processing and interpretation possibilities. An algorithm is presented that locates returns from interfaces in the presence of noise for a non-minimum delay wavelet. The method performs a simple inversion in the frequency domain, enhanced by a time dependent weight designed to recognize the shape of the wavelet amplitude and phase spectra. Thin ice layers are resolved down to a few centimeters and are distinguished from an ice free condition by means of a matched filter system designed to recognize the interference pattern from parallel interfaces close to one another. The effects and constraints imposed by water layers on wet ice are discussed, as are general attenuation, sloping bottom, and critical angle effects in deeper water. In closing, observations on the problems and prospects of this sort of surveying are offered.
    Type of Medium: Series available for loan
    Pages: v, 31 Seiten , Illustrationen
    Series Statement: CRREL Report 91-15
    Language: English
    Note: Contents Preface Nomenclature Introduction Field surveys Methods and paraphernalia Results Sloping bottom effects and critical angle phenomena Deconvolution and thin layers Well-separated echoes Thin ice layers Thin layers of water Observations Literature cited Abstract
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  • 11
    Call number: ZSP-201-90/9
    In: CRREL Report, 90-9
    Description / Table of Contents: In 1986, a mobility model was developed for predicting the traction and motion resistance of both wheeled and tracked vehicles on shallow snow, and a winter field season was dedicated to gathering mobility data for a diverse family of vehicles (including four on wheels and three tracked) to validate the model. The original version of the model, SSM 1.0, used the Mohr-Coulomb shear failure equation from soil mechanics to predict gross traction. This required input of the snow strength parameters c and ȹ. Motion resistance is predicted by calculating the amount of work done by the tire in compacting snow and only requires snow depth and density values as input snow properties. Some effort was expended in determining an easy and reliable method of obtaining snow strength established from past instrumented vehicle test results. Historically, shear annulus apparati have been used to obtain Mohr-Coulomb strength parameters. A comparison of snow strength obtained via these three methods (shear annulus, instrumented vehicle, calculated from initial density using the relationship in SSM 1.0) for individual snow covers showed no agreement. SSM 1.0 assumed that snow strength parameters for mobility prediction were a function of initial snow density; however, traction is developed in the compacted snow under the driving element, whose strength properties bore little relation to those of the initial snow. It appears that the shear strength of the compacted snow is essentially a constant for all of the vehicles and snow covers tested here. Based on this finding, a new traction algorithm was developed, resulting in the creation of a second generation model, SSM 2.0. This algorithm predicts gross traction, on the average for the vehicles tested, within 7% of the measured value. Motion resistance prediction remains unchanged in SSM 2.0. This quantity is still not predicted with a desirable level of accuracy.
    Type of Medium: Series available for loan
    Pages: v, 72 Seiten , Illustrationen
    Series Statement: CRREL Report 90-9
    Language: English
    Note: CONTENTS Preface Nomenclature Introduction Background Field experiments Test location and test sites Test vehicles Test procedures Results CIV traction and motion resistance Wheels/trackcs vehicles traction and motion resistance Shear annulus device Accuracy and limitations of data Snow conditons Analysis Determination of snow strength parameters Traction analysis Traction model predictions Resistance analysis Resistance model predictions Conclusions and recommendations Literature cited Appendix A: Shallow snow mobility model, version 1.0 Appendix B: Test vehicle data Appendix C : Selected test data Appendix D : Snow data Appendix E: Shallow snow mobility model code, version 2.0 Abstract
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  • 12
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    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
    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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  • 13
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    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.
    Type of Medium: Series available for loan
    Pages: iii, 23 Seiten , Illustrationen
    Series Statement: CRREL Report 89-14
    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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  • 14
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    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.
    Type of Medium: Series available for loan
    Pages: iii, 54 Seiten , Illustrationen
    Series Statement: CRREL Report 89-19
    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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  • 15
    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
    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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  • 16
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    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
    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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  • 17
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    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.
    Type of Medium: Series available for loan
    Pages: v, 105 Seiten , Illustrationen
    Series Statement: CRREL Report 89-21
    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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  • 18
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    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
    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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  • 19
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    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
    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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  • 20
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    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
    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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  • 21
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    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
    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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  • 22
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    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
    Language: English
    Note: CONTENTS Abstract Preface Nomenclature Introduction Experimental setup and procedure Experimental results Discussion and conclusions Literature cited
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  • 23
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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
    Language: English
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  • 24
    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.
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    Pages: iii, 21 Seiten , Illustrationen
    Series Statement: CRREL Report 88-1
    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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  • 25
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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
    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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  • 26
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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.
    Type of Medium: Series available for loan
    Pages: v, 63 Seiten , Illustrationen
    Series Statement: CRREL Report 88-13
    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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  • 27
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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
    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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  • 28
    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
    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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  • 29
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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
    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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  • 30
    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
    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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  • 31
    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
    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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  • 32
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    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
    Language: English
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  • 33
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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
    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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  • 34
    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
    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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  • 35
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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
    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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  • 36
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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.
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    Pages: v, 50 Seiten , Illustrationen
    Series Statement: CRREL Report 87-21
    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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  • 37
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    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
    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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  • 38
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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.
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    Pages: vi, 43 Seiten , Illustrationen
    Series Statement: CRREL Report 87-22
    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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  • 39
    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
    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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  • 40
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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
    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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  • 41
    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.
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    Pages: iv, 15 Seiten , Illustrationen
    Series Statement: CRREL Report 86-6
    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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  • 42
    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
    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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  • 43
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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
    Language: English
    Note: CONTENTS Abstract Preface Nomenclature Introduction Aerodynamically rough surface Aerodynamically smooth surface Scalar transfer coefficients Conclusions Literature cited
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  • 44
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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
    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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  • 45
    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
    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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  • 46
    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.
    Type of Medium: Series available for loan
    Pages: v, 52 Seiten , Illustrationen
    Series Statement: CRREL Report 86-18
    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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  • 47
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    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.
    Type of Medium: Series available for loan
    Pages: v, 56 Seiten , Illustrationen
    Series Statement: CRREL Report 86-14
    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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  • 48
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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
    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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  • 49
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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
    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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  • 50
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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.
    Type of Medium: Series available for loan
    Pages: iii, 25 Seiten , Illustrationen
    Series Statement: CRREL Report 86-2
    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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  • 51
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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.
    Type of Medium: Series available for loan
    Pages: v, 79 Seiten , Illustrationen
    Series Statement: CRREL Report 86-5
    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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  • 52
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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
    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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  • 53
    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
    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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  • 54
    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.
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    Pages: v, 49 Seiten , Illustrationen
    Series Statement: CRREL Report 86-11
    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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  • 55
    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
    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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  • 56
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    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
    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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  • 57
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    Associated volumes
    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
    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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  • 58
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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.
    Type of Medium: Series available for loan
    Pages: iv, 53 Seiten , Illustrationen
    Series Statement: CRREL Report 85-22
    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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  • 59
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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
    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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  • 60
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    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
    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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  • 61
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    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
    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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  • 62
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    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.
    Type of Medium: Series available for loan
    Pages: vi, 29 Seiten , Illustrationen
    Series Statement: CRREL Report 85-3
    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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  • 63
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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
    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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  • 64
    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
    Language: English
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  • 65
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    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-79/8
    In: CRREL Report, 79-8
    Description / Table of Contents: Sea ice ridging statistics obtained from a series of laser surface roughnessprofiles are examined. Each set of profiles consists of six 200-km-long flight tracks oriented approximately perpendicular to the coastline of the Chukchi and Beaufort Seas. The landward ends of the profiles were located at Point Lay, Wainwright, Barrow, Lonely, Cross Island and Barter Island. The flights were made in February, April, August, and December 1976, and one additional profile was obtained north of Cross Island during March 1978. It was found that although there is a systematic variation in mean ridge height (h) with season (with the highest values occurring in late winter), there is no systematic spatial variation in h at a given time. The number of ridges/km (micron) is also high during the late winter, with the highest values occurring in the Barter and Cross Island profiles . In most profiles, the ice 20 to 60 km from the coast is more highly deformed (higher micron values) than the ice either nearer the coast or farther seaward. The Wadhams model for the distribution of ridge heights gives better agreement with observed values in the higher ridge categories than does the Hibler model. Estimates of the spatial recurrence frequency of large pressure ridges are made by using the Wadhams model and also by using an extreme value approach. In the latter, the distribution of the lagest ridges per 20 km of laser track was found to be essentially normal
    Type of Medium: Series available for loan
    Pages: iv, 28 Seiten , Illustrationen
    Series Statement: CRREL Report 79-8
    Language: English
    Note: CONTENTS Abstract Preface Introduction Data collection and processing Analysis General Variations in ridging Ridge height distributions Occurrence of high ridges The tail of the distribution Extreme values Applications to offshore design Conclusions Literature cited Appendix A. Tabulated ice ridge data
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  • 66
    Call number: ZSP-201-79/7
    In: CRREL Report, 79-7
    Description / Table of Contents: Sediments beneath the Beaufort Sea near Prudhoe Bay, Alaska, were probed at 27 sites using a static cone penetrometer to determine engineering properties and distribution of material types, including ice-bonded sediments. The probe provided both point and casing resistance data and thermal profiles. At five sites these data were correlated with information from adjacent drilled and sampled holes. These control data and the quality of the probe information permitted profiles of sediment type and occurrence of ice-bonded material to be developed along three lines that included various geological features and depositional environments. Material properties were quite variable in the upper 14 m of sediments probed. In general, softer, finer-grained sediments occurred in the upper layers, while penetration refusal was met in stiff gravels to 10 to 12 m below the seabed. Seabed temperatures during the study were all below 0 C. However, because of uncertainties in freezing point values caused by brines, evaluation of the penetration resistance data was required to identify the occurrence of ice-bonded sediments. The coupling of thermal and penetration resistance data revealed that seasonally ice-bonded sediments occurred where the sea ice froze back to or near the seabed. Deeper, perennially frozen sediments also appeared to be present at several probe sites. The penetration data obtained can be used to aid in the design of shallow and deep foundations in both ice-bonded and unfrozen subsea sediments.
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    Pages: iv, 49 Seiten , Illustrationen
    Series Statement: CRREL Report 79-7
    Language: English
    Note: CONTENTS Abstract Preface Introduction Equipment Data collection and reduction Data analysis and interpretation Point penetration resistance and material properties Lithologic and temperature profiles Casing penetration resistance Applications Shallow foundations Deep foundations Foundations in permafrost Correlations with laboratory tests Conclusions Selected bibliography Appendix A: Description of penetrometer and test procedures Appendix B: Point resistance and skin friction data
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  • 67
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    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    In: CRREL Report, 79-5
    Description / Table of Contents: Abstract: This report presents data from an experimental program undertaken to develop information on proposed and existing chemical grout solutions to provide engineering properties in connection with grouting of soils in ambient temperatures of 39° ±1°F (3.88°C) and below. Twelve grout solutions were investigated, including organic chemicals, sodium silicates, cements, and clay (bentonite). Set or gel tests were performed on each chemical solution, in the center of which a thermocouple was placed for measuring the rates of heat of reaction, except those of the cements and the clay. These solutions consisted of the mixing portions of the chemicals and were placed into 4-in.-diam by approximately 6-in.-long cylinders at an ambient temperature of 39°F.
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    Pages: v, 38 Seiten , Illustrationen
    Series Statement: CRREL Report 79-5
    Language: English
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  • 68
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    Call number: ZSP-201-79/3
    In: CRREL Report, 79-3
    Type of Medium: Series available for loan
    Pages: ii, 7 Seiten , Illustrationen
    Series Statement: CRREL Report 79-3
    Language: English
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  • 69
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    Call number: ZSP-201-79/6
    In: CRREL Report, 79-6
    Description / Table of Contents: Nondestructive repetitive plate bearing (RPB) tests were conducted on various test sections in state highways in Maine during 13-15 April 1976. The RPB test consists of making resilient surface deflection measurements during repetitive loadings at various radii from the load plate. The pavement system stiffness was calculated and the resilient modulus values for the various pavement layers were determined with the Chevron computer program for a layered elastic system. A thawed analysis using nondimensional deflection curves for the various sections provided a guide to the susceptibility of the pavement systems to surface failure and pothole development. Some comparisons between stabilized and nonstabilized aggregate and soil were made with calculated stiffness values. The moduli of the various materials were also compared. The residual surface deflections during testing for several pavement systems indicated a linear logarithmic relationship with number of load applications. A relationship between the modulus of the asphalt cement concrete pavement and pavement temperature was developed for the limited temperature range during the testing.
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    Pages: v, 20 Seiten , Illustrationen
    Series Statement: CRREL Report 79-6
    Language: English
    Note: CONTENTS Abstract Preface Conversion factors Introduction Descriptions of road test sections Test equipment and procedures. Field repetitive plate bearing tests Data analysis General Layered-elastic analysis of the pavement systems Statistical analysis. Flexural analysis Summary and conclusions Literature cited Appendix A: Resilient surface deflections for the test points
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  • 70
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    Call number: ZSP-201-79/4
    In: CRREL Report, 79-4
    Description / Table of Contents: A computer model is described to compute the amount of ice accretion on an object under a variety of initial conditions. Numerical techniques are best applied to these problems because of time dependent effects governing the amount of ice collected and also the variety of initial conditions that can lead to ice accumulation. The helicopter rotor icing problem adds an additional complexity since the velocity along the rotor blade varies over a wide range strongly affecting the amounts of ice collected at different blade positions. The physics of ice accretion is reviewed and the accounting for time-dependence in the computer model is described. Some model results are presented and indicate the dependence of ice accretion on velocity, droplet sizes, cloud liquid water content, and temperature for a cylindrical object of constant size.
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    Pages: iii, 39 Seiten , Illustrationen
    Series Statement: CRREL Report 79-4
    Language: English
    Note: CONTENT Abstract Preface Introduction Ice accretion parameters Physics of ice accretion Interaction between water droplets and flow field Time dependence in droplet trajectories Thermodynamic processes at the surface of the object Time dependence in the thermodynamics Time dependence of lesser order Numerical ice accretion model Major subroutines Options for droplet size variations Option for the helicopter rotor case Results Conclusions and future studies Literature cited Appendix A: Computer program
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  • 71
    Call number: ZSP-201-79/1
    In: CRREL Report, 79-1
    Description / Table of Contents: Experiments were conducted to study the flow of water through columns of homogeneous, repacked snow. The gravity flow theory of water flow through snow was verified, although possibly there is some dependence of the relative permeability on the state of metamorphism of the snow. Also, at very large values of saturation there may be some additional flow in saturated channels.
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    Pages: iv, 13 Seiten , Illustrationen
    Series Statement: CRREL Report 79-1
    Language: English
    Note: CONTENTS Preface Symbols Introduction Test procedure Theory Evaluation of the experimental results Example evaluation Results and discussion Literature cited Appendix A. Measured and computed discharge
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  • 72
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    Call number: ZSP-201-79/29
    In: CRREL Report, 79-29
    Description / Table of Contents: An analytical study of the propagation of shock waves in snow was carried out to evaluate the response of medium density snow to high rates of loading. One solution was developed for steady shock waves; this resulted in calculation of pressure jump, density jump and stress wave speed. Correlation with available experimental data was found to be good. Nonsteady shock waves were also considered in order to evaluate wave attenuation rates in snow. Very few data were available to compare with the analytical results, so no definite conclusions on the part of the study could be made. The results show, however, that shock waves that produce plastic deformation attenuate at extremely high rates and that differences in pressure between two waves are quickly eliminated within a short distance. Calculations were also made to evaluate the effect of wave frequency on attenuation rates. The results show that, for plastic waves, frequency is not a predominant factor for determining attenuation rates.
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    Pages: v, 14 Seiten , Illustrationen
    Series Statement: CRREL Report 79-29
    Language: English
    Note: CONTENTS Abstract Preface Nomenclature I. Introduction II. A constitutive law for snow and balance principles III. Compatibility laws and jump equations for stress waves IV. Steady shock waves in snow V. Comparison of steady-wave theory with experimental results VI. A numerical solution to the nonsteady wave problem VII. Jump equations for nonsteady shock waves VIII. Reduced jump equations Discussion and conclusions Literature cited
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  • 73
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    Call number: ZSP-201-79/28
    In: CRREL Report, 79-28
    Description / Table of Contents: Transmission and scanning electron micrographs of Umiat bentonite revealed thin, mica-like grains with irregular shapes. Most of the bentonite showed electron diffraction ring patterns, but some showed hexagonal net patterns as well as ring patterns. The lengths of the unit cells were calculated to be 5.18 A along the a-axis and 8.97 A along the b-axis. Semiquantitative analyses were made using an energy dispersive spectrometer. Common elements such as Si, Ti, Al, Fe, Mg, Na and K were determined. The molecular ratio of SiO2:Al2O3 was calculated to be 492:100 for the bulk sample, indicating that Umiat bentonite is similar in most respects to Wyoming bentonite, and is classified as a mont-morillonite. The microstructure of frozen Umiat bentonite was observed at a specimen temperature of -100 C using a scanning electron microscope equipped with a cold stage. Frozen bentonite and segregated ice patterns formed from wet bentonite were examined using an X-ray map and Si X-ray line scan. Sublimation processes of ice in the frozen bentonite were observed at specimen temperatures of -60 and -80 C. After sublimation of the ice the bentonite displayed a honeycomb structure. It was concluded that the freezing-sublimation cycle in frozen soil increases the permeability of water vapor due to the three-dimensional structure of the coagulated clay formed by freezing.
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    Pages: iii, 14 Seiten , Illustrationen
    Series Statement: CRREL Report 79-28
    Language: English
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  • 74
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    Call number: ZSP-201-79/25
    In: CRREL Report, 79-25
    In: Charged dislocation in ice, I.
    Description / Table of Contents: The motion of dislocations in single crystal ice under an electric field was observed by using X-ray topographic methods. Electric charge density on these dislocations was deduced from the amplitude and length of the dislocation segment under the known AC electrical field. The most likely linear charge density was about +5x10^-11 c/m, although considerable variation is possible depending on the effective field acting on the dislocation lines.
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    Pages: iii, 12 Seiten , Illustrationen
    Series Statement: CRREL Report 79-25
    Language: English
    Note: CONTENTS Abstract Preface Introduction Theory Experimental apparatus and procedure Results Discussion Concluding remarks Selected bibliography Appendix A. Mosotti type field on core of cylindrical cavity
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  • 75
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    Call number: ZSP-201-79/24
    In: CRREL Report, 79-24
    Description / Table of Contents: By using a new thermocoring technique, a hole was successfully drilled through the 416-m thickness of the Ross Ice Shelf at J-9 Camp. This report provides a description of the drill and an account of this drilling project. A provisional examination of the core shows the ice shelf to consist of 410 m of snow and glacial ice underlain by 6 m of sea ice formed by direct freezing of sea water to the bottom of the Ross Ice Shelf.
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    Pages: ii, 12 Seiten , Illustrationen
    Series Statement: CRREL Report 79-24
    Language: English
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  • 76
    Call number: ZSP-201-79/23
    In: CRREL Report, 79-23
    Description / Table of Contents: The performance of surface impedance and magnetic induction electromagnetic subsurface exploration techniques was studied seasonally at various sites in Alaska where permafrost and massive ground ice occurred. The surface impedance method, which uses radiowaves in the LF and VLF bands, and the magnetic induction method, which uses low-frequency magnetic induction fields, distinguish subsurface materials by the electrical resistivity of the materials. The methods used have greatest sensitivity within about 20 m of the surface and are, therefore, most applicable for shallow subsurface investigations. The selection of study sites was based on anticipated contrasts in electrical resistivity between ground ice and adjacent earth materials. A magnetic induction instrument, using a separation of 3.66-m between the transmitter and receiver antennas, in general was able to detect near-surface zones of massive ice and to provide data regarding permafrost distribution in both the Fairbanks and Prudhoe Bay areas. At this antenna separation, the depth of magnetic field penetration was sufficient to include mainly the zone containing maximum contrasts in resistivity between ground ice and other earth materials. In the Fairbanks area, contrasts, in this zone were greatest in late winter when the seasonally thawed surface layer was completely frozen. When thawed, this layer usually becomes more conductive and often masks the deeper resistivity contrasts. In the Prudhoe Bay area, maximum ground resistivity contrasts were detected in late summer when shallow subsurface temperatures had risen sufficiently to permit resistivity contrasts between the massive ice and the ice-rich ground to appear.
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    Pages: v, 24 Seiten , Illustrationen
    Series Statement: CRREL Report 79-23
    Language: English
    Note: CONTENTS Abstract Preface Introduction Background Obiectives and procedures Ground electrical resistivity in permafrost regions Electromagnetic techniques General Magnetic induction method Surface impedance fradiowave method Direct current method General description of field sites Results Site 1 CRREL permafrost station, Fairbanks, Alaska Site 2 Planned road cut for Steese Highway near Fox, Alaska Site 3 Relic floodplain near Fairbanks, Alaska Site 4 Pingos, Prudhoe Bay, Alaska Site 5 Ice wedges, Prudhoe Bay, Alaska Comparisons between the surface impedance and magnetic induction methods Conclusions and recommendations Literature cited Appendix A. Discussion of the depth of sensitivity of the magnetic induction method using two- and three-layer apparent resistivity curves
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  • 77
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    Call number: ZSP-201-79/12
    In: CRREL Report, 79-12
    Description / Table of Contents: An analysis of a point source bubbler system used to induce local melting of an ice cover is presented. The analysis leads to a numerical simulation programmed in FORTRAN which may be used to predict the effectiveness of such systems. An example application is presented using a typical record of average daily air temperatures. The FORTRAN program for the point source simulation as well as a FORTRAN program for line source systems are included in the Appendix.
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    Pages: iii, 12 Seiten , Illustrationen
    Series Statement: CRREL Report 79-12
    Language: English
    Note: CONTENTS Abstract Preface Introduction Outline of analysis Plume analysis Heat transfer analysis Temperature of impinging plume Heat transfer coefficient Melting of the ice cover Simulation example Thermal reserve analysis Literature cited Appendix
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  • 78
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    Call number: ZSP-201-79/13
    In: CRREL Report, 79-13
    Description / Table of Contents: Heat transfer in turbulent flow was measured in a rectangular channel with a width of 0.254 m and a flow depth of 0.0254 m. Correlations between the Nusselt and Reynolds numbers are given for a range of 3020 Re 22360. A Prandtl number range of 9.90 or = Pr or = 12.28 for water was used in the tests. The results are compared with those of other investigations and show that some well-known correlations underpredict the heat transfer by about 35%.
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    Pages: ii, 5 Seiten , Illustrationen
    Series Statement: CRREL Report 79-13
    Language: English
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  • 79
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    Call number: ZSP-201-79/10
    In: CRREL Report, 79-10
    Description / Table of Contents: Ice cores from Byrd Station and Little America V have been used to test an ultrasonic technique for evaluating crystal anisotropy in the Antarctic Ice Sheet. P-wave velocities measured parallel and perpendicular to the vertical axes of cores from the 2164-m-thick ice sheet at Byrd Station have yielded results in excellent agreement with the observed c-axis fabric profile and with the in-situ P-wave velocity profile measured parallel to the bore hole axis. Velocity differences in excess of 140 m/s for core samples from deeper than 1300 m attest to the strong single pole clustering of crystallographic c-axes about the vertical, especially in the zone from 1300-1800 m. Such oriented structure is compatible only with strong horizontal shearing in this zone. The existence in an ice sheet of widespread shearing several hundred meters above its bed raises serious questions as to the validity of current concepts of the flow of large ice masses that tend to gloss over or ignore crystal alignments of this magnitude.
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    Pages: IV, 16 Seiten , Illustrationen
    Series Statement: CRREL Report 79-10
    Language: English
    Note: CONTENTS Abstract Preface Introduction Laboratory measurements Sample sources Ultrasonic velocity measurements Effects of inclined drilling at Byrd Station Results Byrd Station Little America V Summary and conclusions Literature cited
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  • 80
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    Call number: ZSP-201-85/19
    In: CRREL Report, 85-19
    Description / Table of Contents: Ground-probing radar can be an effective tool for exploring the top 10 to 20 m of ground, especially in cold regions where the freezing of water decreases signal absorption. However, the large electrical variability of the surface, combined with the short wavelengths used, can often cause severe ground clutter that can mask a desired, deeper return. In this study a model facility was constructed consisting of a metallic reflector covered by sand. Troughs of saturated sand were emplaced at the surface to vary surface electrical properties and to act as a noise source to interfere with the bottom reflections. Antenna polarization and height, and signal stacking in both static (antennas stationary) and dynamic (antennas moving) modes were then investigated as methods for reducing the surface clutter. Polarization parallel to the profile direction (perpendicular to the troughs' axes) gave profiles superior to the perpendicular case because of the directional sensitivity of the antenna radiation. Dynamic stacking greatly improved the signal-to-noise ratio because noise sources were averaged as the antennas moved, while the desired reflector, buried at constant depth, was enhanced. Raising the antennas above the surface also reduced noise because the surface area over which reflections were integrated increased. All three noise reduction techniques could be effective in surveys for reflectors at nearly constant depth such as groundwater tables or ice/water interfaces if the lateral variation in undesired ground propertiesis sufficiently random.
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    Pages: iv, 23 Seiten , Illustrationen
    Series Statement: CRREL Report 85-19
    Language: English
    Note: CONTENTS Abstract Preface Introduction Objective and procedures Materials and methods Subsurface radar Model facility Results Isolated disturbances-surface and raised analog profiles Multiple disturbances Discussion and conclusions Literature cited
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  • 81
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    Call number: ZSP-201-79/30
    In: CRREL Report, 79-30
    Description / Table of Contents: The ice suppression resulting from discharge of warm water into rivers during winter is analyzed with emphasis on two different cases. In Part 1 the case of a thermal effluent fully mixed across the flow section is analyzed to include the effects of unsteadiness in the effluent temperature and the meteorological variations. The location of the ice edge is determined either by a 0 C water temperature criterion or an equilibrium ice melting analysis. The choice of the applicable criterion emerges naturally from the analysis even though the location of the ice edge may be considerably different when a steady-state analysis is done. In Part 2 the case of a side discharge of heated effluent is analyzed, also in an unsteady manner, and the effects of transverse dispersion are included in the analysis. Comparisons are made in both Parts 1 and 2 to limited field data that are available.
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    Pages: iv, 23 Seiten , Illustrationen
    Series Statement: CRREL Report 79-30
    Language: English
    Note: CONTENTS Abstract Preface Part I. Unsteady suppression of river ice by fully mixed thermal effluents Introduction Governing equations Outline of analysis Location of ice edge Numerical simulation Uncertainties and Imitations Literature cited Part II. Effect of transverse mixing on ice suppression Introduction Analysis of dispersion and heat loss Analysis of ice thickening and melting Numerical simulation Example simulations Field comparison Uncertainties and limitations Literature Cited Appendix A: Computer program for unsteady fully mixed ice suppression Appendix B: Computer program for unsteady lateral mixing ice suppression
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  • 82
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    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-79/9
    In: CRREL Report, 79-9
    Description / Table of Contents: Sedimentation at the terminus of the Matanuska Glacier has been found to be primarily subaerial in a 100- to 300-m wide, ice-cored zone paralleling the edge of the active ice. Certain physical and chemical characteristics of the ice and debris of the superglacial, englacial and basal zones of the glacier indicate the debris of the basal zone, the primary source of sediment, is entrained during freeze-on of meltwater, probably surficially derived, to the glacier sole. Till formation results from the melting of buried ice of the basal zone. Melt-out till inherits the texture and particle orientations of basal ice debris; other properties are not as well preserved. Most deposits result from resedimentation of till and debris by sediment gravity flows, meltwater sheet and rill flow, slump, spall, and ice ablation. Depositional processes are interrelated in the process of backwasting of ice-cored slopes. Sediment flows are the primary process of resedimentation. Their physical characteristics, multiple mechanisms of flow and deposition, and characteristics of their deposits vary with the water content of the flow mass. Deposits of each process are distinguished from one another by detailed analysis of their internal organization, geometry and dimensions, and the presence of other internal and related external features. Genetic facies are defined by these characteristics. The interrelationship of processes develops a composite depositional sequence defined in terms of genetic facies associations; an upper, resedimented facies association, a middile, till facies association, and a lower, subglacial-resedimental facies association. The lateral and vertical distribution of genetic facies within the associations is mainly nonrepetitive.
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    Pages: X, 112 Seiten , Illustrationen , 1 Beilage
    Series Statement: CRREL Report 79-9
    Language: English
    Note: CONTENTS Abstract Preface Summary Chapter 1. Introduction Field site Historical background Chapter 2. Characteristics of the debris and ice Characteristics of the facies and subfacies Basal zone Characteristics of the debris Discussion Chapter 3. Oxygen isotope analysis Sampling and analysis Results Discussion Chapter 4. Depositional processes—till formation Methods of analysis Environmental setting Till formation Chapter 5. Depositional processes—resedimentation Sediment flows Other resedimentation processes Resedimentation process relationships Chapter 6. Process distribution, sediment dispersal and depositional patterns Physical characteristics Sediment dispersal Sedimentary facies Patterns of terminus sedimentation Chapter 7. Conclusions Literature cited
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  • 83
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    Call number: ZSP-201-79/21
    In: CRREL Report, 79-21
    Description / Table of Contents: The report studies the question of whether Great Lakes freighters could move effectively through ice-clogged channels with the aid of tows provided by warping or kedging systems. Ten operational concepts are outlined, and their advantages and disadvantages are noted. The crushing resistance of floating brash ice is then analyzed. The neutral, active and passive states of stress for laterally confined brash ice are considered, and the resistance to horizontal thrusting by a smooth vertical wall is calculated for cohesionless brash ice, and for ice in which there is finite cohesion between the ice fragments. The thickening of the ice cover in the vicinity of a "pusher", and the formation of pressure ridges, are analyzed in order to estimate the amount of pile-up that can occur against a ship hull. The analysis then moves on to consideration of ship resistance by brash ice, taking into account crushing resistance at the bow, tangential friction at the bow, and hull friction aft of the bow section. Comparisons are made between thrust from the ship’s screws and the calculated ice resistance. The next section of the report estimates the force requirements for a warping or kedging system in terms of thrust augmentation for existing vessels. Tow cable requirements are given, and estimates are made for cable anchors and for anchorage of underwater structures. The force and power requirements for winches and windlasses are given, the practical problems involved in the pickup or transfer of cables are mentioned, and the report concludes with a brief appraisal. The conclusion is that a simple warping tug system is appropriate for a full scale experiment, a chain ferry with auxiliary barge seems attractive for an operational system, and a chain ferry plow may be an efficient way to clear ice from channels.
    Type of Medium: Series available for loan
    Pages: iv, 21 Seiten , Illustrationen
    Series Statement: CRREL Report 79-21
    Language: English
    Note: CONTENTS Abstract Preface Introduction Operational concepts A. Warping tug system B. Chain ferry system C. Chain ferry with auxiliary barge D. Ski tow system E. Dual winch warping system F. Simple kedging G. Trailing-line system H. Above-surface dual winch system I. Pulley systems J. Chain ferry plow Crushing resistance of fragmented ice covers Resistance to ship passage by broken ice Crushing resistance at the bow Tangential friction at the bow Hull friction aft of the bow section Total ship resistance from brash ice Comparison of ship thrust and ice resistance Force requirements for a warping or kedging system Tow cable requirements Anchors and anchorages Force and power requirements for winches and windlasses Pickup or transfer of cable General appraisal Literature cited
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  • 84
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    Call number: ZSP-201-79/11
    In: CRREL Report, 79-11
    Description / Table of Contents: A theory of the optical properties of snow in the 2-20 region of the infrared has been developed. Using this theory it is possible to predict the absorption and scattering coefficients and the emissivity of snow, as a function of the snow parameters of grain size and density, for densities between 0.17 and 0.4 g/cm3. The absorption and scattering coefficients are linearly related to the density and inversely related to the average grain size. The emissivity is independent of grain size and exhibits only a weak dependence upon density.
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    Pages: iii, 9 Seiten , Illustrationen
    Series Statement: CRREL Report 79-11
    Language: English
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  • 85
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    Call number: ZSP-201-79/15
    In: CRREL Report, 79-15
    Description / Table of Contents: This report discusses the application of several modern geophysical techniques to groundwater exploration in areas in permafrost. These methods utilize the principles of magnetic induction and radiowave surface impedance in the 10- to 400-kHz band, the techniques of impulse and side-looking radar in the 50- to 10,000-MHz band, and also some optical techniques using imagery obtained from a satellite. Low frequency case studies demonstrate the use of the techniques for detecting free water under an ice cover in shallow, almost completely frozen lake basins, and thaw zones within lake beds, stream channels, and in permafrost in general. The radar studies demonstrate the use of these techniques for determining depth of free water and ice cover thickness on lakes and rivers
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    Pages: iv, 30 Seiten , Illustrationen
    Series Statement: CRREL Report 79-15
    Language: English
    Note: CONTENTS Abstract Preface Introduction Part I. Low frequency resistivity methods Resistivity of earth materials Theory and description of techniques Surface impedance technique Airborne radiowave technique Magnetic induction technique Case studies Location of thaw zones beneath lakes and rivers Location of permeable materials in unfrozen ground Delineating permafrost boundaries Part II. High frequency dielectric methods Dielectric properties of earth materials Theory and description of equIpment Profiling radar Imaging radar Case studies Radar profile of a river channel Impulse radar profile of a freshwater lake SLAR imagery of Arctic lakes Literature cited Appendix A: Satellite imagery for subsurface water exploration
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  • 86
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    Call number: ZSP-201-79/20
    In: CRREL Report, 79-20
    Description / Table of Contents: A volumetric constitutive equation was developed to characterize the behavior of snow subjected to large compressive volumetric deformations. By treating the material as a suspension of air voids in a matrix material of polycrystalline ice, a rate-dependent volumetric constitutive law was formulated and found to accurately predict material response to pressure loads for a wide range of load rates. Comparison of the theory with shock wave data was not considered in this paper, although the constitutive law appears to be valid for such load situations. One application to oversnow mobility of tracked vehicles was made. In this case, power requirements due to snow compaction were calculated parametrically in terms of vehicle speed, track loading, and snow density.
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    Pages: v, 13 Seiten , Illustrationen
    Series Statement: CRREL Report 79-20
    Language: English
    Note: CONTENTS Abstract Preface Nomenclature Introduction Material representation of ice Development of the volumetric constitutive law for snow Fully elastic phase Elastic-plastic phase Fully plastic phase Simplified equation Comparison with experimental data Application to vehicle mobility problems Conclusions Literature cited
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  • 87
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    Call number: ZSP-201-79/18
    In: CRREL Report, 79-18
    Description / Table of Contents: Temperatures of the subgrade and of sulfur foam insulation test sections in an expedient road were monitored with thermocouples to document freezing and thawing conditions. Vehicular trafficking was conducted on a limited basis to determine the load supporting capabilities of the foam. The sulfur foam, placed directly under a prefabri­cated surface mat, was found to be unsuitable for use as an expedient thermal insulation and traffic load supporting material primarily because of its low tensile strength and high brittleness. The insulating value of sulfur foam pro­duced by the batch process in the field was about one-half that of extruded polystyrene, meaning double the thick­ness for equal protection against thaw.
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    Pages: v, 21 Seiten
    Series Statement: CRREL Report 79-18
    Language: English
    Note: CONTENTS Preface Conversion factors: U.S. customary to metric units of measurement Introduction Site preparation Sulfur foam application Sulfur foaming equipment Environmental aspects Traffic testing and test pad observations Field sampling and temperature readings during pouring Lab tests for physical properties Sulfur foam odor analysis Insulation costs Lab experiments with sulfur foam Conclusions Literature cited
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  • 88
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    Call number: ZSP-201-79/14
    In: CRREL Report, 79-14
    Description / Table of Contents: Solid ice growth rates due to the presence of frazil slush beneath the ice cover have been shown to be greater than the so-called static growth. The frazil slush reduces the effective heat of ice solidification and the frazil particles freeze into the interstitial water. Numerical schemes are presented which clearly show the effect of frazil ice porosity on ice cover growth rates and the numerical model using air temperature as the major input is compared with field data on ice thickness in a small river laden with frazil ice beneath its cover.
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    Pages: ii, 4 Seiten , Illustrationen
    Series Statement: CRREL Report 79-14
    Language: English
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  • 89
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    Call number: ZSP-201-79/22
    In: CRREL Report, 79-22
    Description / Table of Contents: Field observations at 60 Sites located in the fast or near-fast ice along a 1200-km stretch of the north coast of Alaska between Bering Strait and Barter Island have shown that the great majority of the ice samples (95%) exhibit striking c-axis alignments within the horizontal plane. Such alignments were usually well developed by the time the ice was 50 cm thick and in some cases when the ice was 20 cm thick. In all cases the degree of preferred orientation increased with depth in the ice. Representative standard deviations around a mean direction in the horizontal plane are commonly less than ± 10° for samples collected near the bottom of the ice. The general patterns of the alignments support a correlation between the preferred c-axis direction and the current direction at the ice/water interface. A comparison between c-axis alignments and spot current measurements made at 42 locations shows that the most frequent current direction coincides with the mean c-axis direction. Such alignments are believed to be the result of geometric selection with the most favored orientation being that in which the current flows normal to the (0001) plates of ice that compose the dendritic sea ice/sea water interface.
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    Pages: v, 21 Seiten , Illustrationen
    Series Statement: CRREL Report 79-22
    Language: English
    Note: CONTENTS Abstract Preface Summary Introduction Techniques and sampling Observations Crystal alignments “Odd” sites Causes Conclusions Literature cited Appendix A: Current observations
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  • 90
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    Call number: ZSP-201-79/19
    In: CRREL Report, 79-19
    Description / Table of Contents: The critical velocities of loads moving over floating ice plates have been determined by several authors. In all these analyses it was assumed that the in-plane force field in the ice cover is zero. However, due to constrained thermal strains, in-plane forces do occur in the field. The purpose of the present paper is to determine their effect upon the critical velocities of the moving loads. It is shown that a uniform compression force field reduces the critical velocity, whereas a tension force field has the opposite effect.
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    Pages: ii, 12 Seiten , Illustrationen
    Series Statement: CRREL Report 79-19
    Language: English
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  • 91
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    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-79/17
    In: CRREL Report, 79-17
    Description / Table of Contents: Six test roofs of two different slopes — 16.3° and 39.8°, and three different roof coverings — asphalt shingles, cedar shingles, and corrugated aluminum sheeting, were constructed at USACRREL, Hanover, New Hampshire, and were instrumented with thermocouples, heat flow meters, and calibrated gutters. Measurements were recorded for the winters of 1971-72 and 1972-73. The degree of icing and the chronological changes in the snow cover were recorded on 35-mm Kodachrome slides. It was found that eave icing is a sensitive function of the slope, roof covering composi­tion, and solar radiation. The effects of wind were not investigated; the data were screened to remove all informa­tion corresponding to windspeeds over 8 km/h. In order of increasing tendency to form ice dams on the eaves, the roofs were high-slope asphalt, high-slope cedar, high-slope aluminum, low-slope asphalt, low-slope cedar, and low- slope aluminum.
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    Pages: vi, 40 Seiten , Illustrationen
    Series Statement: CRREL Report 79-17
    Language: English
    Note: CONTENTS Abstract Preface Summary Introduction Experimental procedure Description of roofs Meteorological data Procedure Analysis General Temperature profiles Temperature rankings Heat flow Snow depths and meltwater volumes Degree of icing Results and conclusions General Temperature profiles of the roofs Comparative temperatures of roofs by section — rankings Heat flow and accumulation Snow depth, coverage, and meltwater Degree of icing Discussion of the icing problem Literature cited
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  • 92
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    Call number: ZSP-201-79/16
    In: CRREL Report, 79-16
    Description / Table of Contents: In 1973 two membrane encapsulated soil layer (MESL) test sections were constructed into existing gravel surfaced roads at Elmendorf A FB and at Ft. Wainwright in Anchorage and Fairbanks, Alaska, respectively. The Elmendorf AFB MESL contains a silty clay soil and the Ft. Wainwright MESL contains a nonplastic silt. Both sections were constructed at soil moisture contents of approximately 2% to 3% below optimum for the CE-12 compactive effort. There were no indica­tions of soil moisture migration during freezing in either test section and after-thaw field California Bearing Ratio values were nearly equal to values measured before freezing. There is growing evidence of a slight increase in the overall soil moisture content in the Elmendorf AFB MESL possibly from moisture entering through the single layer polyethylene sidewalls which were not treated with asphalt emulsion. There is good evidence that the membrane of the same section might have received damage during a soil sampling operation which allowed localized moisture infiltration. A two-layer polyethylene membrane used in the Ft. Wainwright MESL is considered a more positive moisture barrier than the single sheet and a justifiable added cost for permanent construction.
    Type of Medium: Series available for loan
    Pages: v, 27 Seiten , Illustrationen
    Series Statement: CRREL Report 79-16
    Language: English
    Note: CONTENTS Preface Introduction Laboratory studies General Elmendorf AFB silty clay Fairbanks silt Field studies Elmendorf AFB MESL Ft. Wainwright MESL Traffic use Elmendorf AFB MESL Ft. Wainwright MESL Performance observations Elmendorf AFB MESL Ft. Wainwright MESL Conclusions Elmendorf AFB MESL Ft. Wainwright MESL General Literature cited Appendix A. The MESL concept Appendix B. Classification, compaction, freezing and CBR test results for Fairbanks silt
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  • 93
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    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-79/27
    In: CRREL Report, 79-27
    Description / Table of Contents: Some Bessel function identities found by solving problems of the deflection of a floating ice plate by two different methods are rigorously proved. The master formulas from which all the identities are derived are in a Fourier reciprocal relationship, connecting a Hankel function to an exponential function. Many new formulas can be derived from the master formulas. The analytical method presented here now opens the way to study a hitherto impossible type of problem--the deflection of floating elastic plates of various shapes and boundary conditions.
    Type of Medium: Series available for loan
    Pages: ii, 13 Seiten , Illustrationen
    Series Statement: CRREL Report 79-27
    Language: English
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  • 94
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    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-79/26
    In: CRREL Report, 79-26
    Description / Table of Contents: A 19-year record of the annual closing and opening dates of operation of the Lake Champlain ferry at Grand Isle, Vermont, which are controlled by the lake's ice cover, was made available to CRREL. These navigation records accurately approximated the freeze-over and breakup dates for the ferry crossing area between Gordon Landing, Vermont, and Cumberland Head, New York. When compared statistically with water temperature and climatological data for the same years at nearby Lake Champlain locations, the dates allowed accurate predictions of ice formation. From nearby air temperature records, cumulative freezing degree-day (deg C) curves were plotted for each year of record, and ice formation dates and standard deviations were predicted with considerable accuracy. Several methods of predicting ice formation on Lake Champlain were attempted. The most accurate approach used a combination of water temperatures and freezing degree-days. The influence of wind speed on ice cover formation and prediction are also discussed in the report.
    Type of Medium: Series available for loan
    Pages: v, 21 Seiten , Illustrationen
    Series Statement: CRREL Report 79-26
    Language: English
    Note: CONTENTS Abstract Preface Introduction Data tabulation and collection Air temperatures 11-reezing degree-days Water temperatures Closing and opening dates Results Air temperature Freezing degree-days Water temperatures Analysis: Attempted methods of predicting ice formation Predicting air temperatures 8Summer water temperatures Fall water temperatures and freezing degree-days Wind speed influence on closing of the lake Water temperature vs surface air temperature analysis Prediction of ice-out dates Conclusions Literature cited Appendix A. Freezing degree-day curves with ice notations and watertemperature notations Appendix B. Summary
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  • 95
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    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-78/3
    In: CRREL Report, 78-3
    Description / Table of Contents: The mathematical theory for the bearing capacity of river ice for vehicles is presented. The floating ice sheet is assumed to have simple supports at the shore line. Solutions are presented for loads uniformly distributed over circular and rectangular areas. Numerical evaluations are made for a number of vehicles and the results presented in graphical form
    Type of Medium: Series available for loan
    Pages: iii, 22 Seiten , Illustrationen
    Series Statement: CRREL Report 78-3
    Language: English
    Note: CONTENTS Abstract Preface Conversion factors: U.S. customary to metric (SI) units of measurement Introduction Theory Solution by superposition Solution by Fourier integral Solution by Fourier series Application and results Literature cited Appendix A: Bearing capacity of river ice for military vehicles Appendix B: Vehicle specifications Appendix C: Fortran II computer program
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  • 96
    Call number: ZSP-201-78/28
    In: CRREL Report, 78-28
    Type of Medium: Series available for loan
    Pages: x, 112 Seiten , Illustrationen
    Series Statement: CRREL Report 78-28
    Language: English
    Note: CONTENTS Abstract Preface Conversion factors Introduction Descriptions of road test sections Test equipment and procedures Field repetitive plate bearing tests Data analysis General Layered-elastic analysis of the pavement systems Statistical analysis Flexural analysis Summary and conclusions Literature cited Appendix A: Resilient surface deflections for the test points
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  • 97
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    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-78/24
    In: CRREL Report, 78-24
    Type of Medium: Series available for loan
    Pages: v, 12 Seiten , Illustrationen
    Series Statement: CRREL Report 78-24
    Language: English
    Note: CONTENTS Abstract Preface Introduction Comparison of winters Ship effects Measured forces Sequential breaking of the structure Discussion Conclusions Recommendations Literature cited Appendix A. Force level fluctuations in west ice boom, 20 January 1977
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  • 98
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    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-78/19
    In: CRREL Report, 78-19
    Type of Medium: Series available for loan
    Pages: iv, 21 Seiten , Illustrationen
    Series Statement: CRREL Report 78-19
    Language: English
    Note: CONTENTS Abstract Preface Introduction Previous work Methods and results Methods of analysis Salinity-chlorophyll a associations Discussion Comparison of ice and water column standing crops Estimated mass of ice associated chl. a Mechanism of ice algae formation in the Weddell Sea Differences between the biological environments of fast and drifting pack ice Conclusions Literature cited Appendix A. Species variations - ice and water column
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  • 99
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    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-78/17
    In: CRREL Report, 78-17
    Description / Table of Contents: Abstract: This investigation utilized historical and recent aerial photographs and satellite imagery in 1) estimating changes in positions of the high-water line and sea cliff break and base, in rates of accretion and/or erosion, and in volumes of transported sediment, and 2) providing a preliminary evaluation of the direction of littoral transport along the outer Cape Cod coast. Using aerial photographs acquired in 1938, 1952, 1971 and 1974 with manual photointerpretation techniques, changes in the distances from selected reference points to the cliff break, cliff base and the high-water line were measured. LANDSAT-1 and -2 imagery acquired from 1 September 1972 to 28 May 1975 was evaluated for use in determining the directions of littoral transport that are active the predominant amount of time. Although the imagery has been very useful for this purpose at other locations, it proved to be useless along the outer shore of Cape Cod. Largest net migrations of the high water line from 1938 to 1974 occurred in the northern and southern portions of this coast. The northern maximum high water line was 321.4 ft, the southern was 1794.6 ft. The central portion of the coast was generally more stable with changes varying from 6.8 to 157.6 ft. Cliff-base recession rates varied from 0.4 to 7.3 ft/yr. Maximum estimated net volume of sediment deposited per linear foot of beach from 1938 to 1974 was 334 yd^3 (based on 2 yd^3/ft of recession or accretion); maximum eroded was 914 yd^3. Changes in the configuration of spits were used to evaluate directions of littoral transport since suspended sediment concentrations were generally not sufficient to act as natural tracers of surface currents. Based on the literature and a determination of the portion of the coast perpendicular to the direction of dominant wave approach, the location of the nodal zone for predominant littoral directions of drift probably shifts between the area near Spectacle Pond and North Truro Air Force Station. This investigation has illustrated a photo interpretation technique that is useful in performing a reconnaissance of coastal change. The data obtained from this method can be used to supplement those acquired by ground surveys and are valid as first approximations for planning subsequent, more detailed surveys.
    Type of Medium: Series available for loan
    Pages: vi, 49 Seiten , Illustrationen
    Series Statement: CRREL Report 78-17
    Language: English
    Note: CONTENTS Abstract Preface Conversion factors: U.S. customary to metric units of measurement Introduction Background Previous investigations Analytical procedures Results and discussion Shoreline changes: High-water line Shoreline changes: Cliff recession Volumetric changes Nodal zone location and direction of littoral transport Error evaluation Summary and conclusions Future research Selected bibliography Appendix A: Maps of shoreline with overlays for 1938, 1952, 1971 and 1974 Appendix B: Supplementary data for estimating shoreline change
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  • 100
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-78/14
    In: CRREL Report, 78-14
    Description / Table of Contents: The analytical solution and the numerical study of the eigenvalue problem for determining the buckling pressure of an infinite elastic plate floating on water and stressed uniformly along the periphery of an internal hole is presented. The boundary conditions considered are the clamped-, simple-, and free-edge conditions. Small buckling pressure occurs only for the free-edge condition. The shape of the deflection for the free-edge condition suggests that buckling is an important mechanism of failure.
    Type of Medium: Series available for loan
    Pages: v, 55 Seiten , Illustrationen
    Series Statement: CRREL Report 78-14
    Language: English
    Note: CONTENTS Abstract Preface Nomenclature Introduction 1. The problem 2. Abstract of the result Part I. Fundamental solutions 3. Fuchsian type solutions 4. Contour integral solution 5. Integration of the integral solution 6. Fundamental solutions for α = 1 7. Fundamental solutions for α = 0 8. Eigenvalues for α = 0 9. Fundamental solutions for α 〉 1 Part II. Asymptotic expansions 10. Asymptotic expansion for 0 〈 α ⩽1 11. Asymptotic expansion for 1 ≦ α ≦ 2 12. Asymptotic expansion for 2 ≦ α ≦ ∞ Part III. Eigenvalues 13. Range of eigenvalues 14. Eigenvalues for the free-edge condition 15. Eigenvalues for the clamped-edge and simple-edge conditions 16. Deflection Acknowledgement Literature cited Appendix A. Analytical continuation at the singular point Appendix B. Tensorial transformations Appendix C. Comparison of the semi-infinite plate buckling with the asymptotic buckling
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