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  • 1
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-82/9
    In: CRREL Report, 82-9
    Description / Table of Contents: This study deals with the distribution of forces along the converging boundaries of the Port Huron, Michigan, region where unconsolidated ice in Lake Huron is held against wind and water stresses. An experimental basin was built to induce uniform shear stress on the model ice cover by flowing water beneath the ice. The boundary segments, which held the ice cover in the region, were instrumented to measure force in the normal and tangential directions. The distribution of normal forces along the boundary was compared with as distribution derived by using a theoretical model. An ice control structure (ICS) was installed in the basin and experiments were conducted to measure the forces on the ICS and the ice release through the opening in the ICS during simulated ship passages. The experimental results are presented in a nondimensional form. In addition, the force per unit length on the ICS and the area of ice released through its opening were estimated for the expected wind conditions at the Port Huron site.
    Type of Medium: Series available for loan
    Pages: v, 27 Seiten , Illustrationen
    Series Statement: CRREL Report 82-9
    Language: English
    Note: CONTENTS Abstract Preface List of symbols Introduction Theoretical models Case 1 Case 2 Case 3 Experimental program Experimental facility Scaling factors Experimental results Analysis of wind data for lower Lake Huron Summary and conclusions Release of ice through the opening of an ICS Ice forces on the ice control structure Ice forces on ice control structure from a large unconsolidated ice cover Literature cited Appendix A. Equation for the stress resultants and velocities of the ice cover Appendix B. Monthly summary of wind data at Port Huron
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  • 2
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-82/34
    In: CRREL Report, 82-34
    Description / Table of Contents: The ice discharge through an opening in an ice control structure was documented to be a function of the floe size, ice type, ice floe conditions and vessel direction. The model data for the average ice discharge per vessel transit scaled to prototype values compared favorably with data taken at the St. Marys River ice control structure (ICS). The model results of the force measurements were also consistent with data taken at the St. Marys ICS. The dynamic loading conditions were independent of vessel direction. The dynamic loading to the structure using 3 types of ice (plastic, natural and urea-doped) showed a considerable difference in their means and standard deviations. The urea-doped ice was evaluated for dynamic loading conditions, and reasonable peak values of 3 to 5 times the mean load at each measuring position were recorded, independent of vessel direction. It appears that synthetic random ice floes may be used in model studies where ice discharge through an opening in a structure needs to be documented. This study shows the synthetic random ice floe discharge to fall reasonably within the values obtained for natural ice discharge for both rafted and non-rafted ice fields above the ICS. However, the question of whether synthetic ice can be used for analyzing force distributions and dynamic force loading criteria cannot be fully answered at this time because the load distributions of the synthetic and natural floes appear to differ.
    Type of Medium: Series available for loan
    Pages: 68 Seiten , Illustrationen
    Series Statement: CRREL Report 82-34
    Language: English
    Note: CONTENTS Abstract Preface Introduction Scope of work Ice discharge from Lake Huron into St. Clair River Water velocity profiles at Port Huron Ice conditions Physical model Basis for selection Description Instrumentation Model ice control structure Open water calibration Open water tests Experimental procedures and techniques Ice cover calibration Ice control structure orientation Analysis of ice discharge due to ship transits Natural ice Synthetic ice Forces on the ice control structure Static measurements Dynamic force measurements Potential additional shear stresses Anticipated ice conditions with ICS Conclusions Literature cited Appendix A. Application of model results Appendix B. Suggested additional studies Appendix C. Derivation of ice discharge
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  • 3
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    Series available for loan
    Wilmette, Ill. : Snow, Ice and Permafrost Research Establishment
    Associated volumes
    Call number: ZSP-201-11
    In: SIPRE report, 11
    Description / Table of Contents: A commercial deep-freeze unit was modified to serve as a laboratory for growing single crystals, cutting specimens of a given orientation, testing these specimens in compressive creep, and studying thin-sections of the results on a universal stage. A method of growing single crystals of adequate size was developed by adapting the Bridgman method. Fortyone creep tests were made at temperatures ranging from -1° to -18°C. These gave an unexpected form of creep-curve in which the rate of strain continuously increases with time. The mechanism of deformation is dominantly basal translation—consistent with earlier work. The dependence on temperature and stress is expressed empirically.
    Type of Medium: Series available for loan
    Pages: 24 Seiten , Illustrationen
    Series Statement: SIPRE report 11
    Language: English
    Note: Contents Introduction Use of the deep-freeze as a cold laboratory Growing single crystals Creep tests Conclusions References cited
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  • 4
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    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-79/8
    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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  • 5
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    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-78/15
    In: CRREL Report, 78-15
    Description / Table of Contents: This report first discusses the general approach for calculating the horizontal forces an ice cover exerts on a structure. Ice force determination consists of two parts: (1) the analysis of the in-plane forces assuming that the ice cover remains intact and (2) the use of a failure criterion, since an ice force cannot be larger than the force capable of breaking up the ice cover. For an estimate of the largest ice force, an elastic plate analysis and a failure criterion are often sufficient. A review of the literature revealed that, in the majority of the analyses, it is assumed that the failure load is directly related to a 'crushing strength' of the ice cover. However, observations in the field and tests in the laboratory show that in some instances the ice cover fails by buckling. This report reviews the ice force analyses based on the buckling failure mechanism and points out their shortcomings. The report then presents a new method of analysis which is based on the buckling mechanism
    Type of Medium: Series available for loan
    Pages: iv, 13 Seiten , Illustrationen
    Series Statement: CRREL Report 78-15
    Language: English
    Note: CONTENTS Abstract Preface Introduction and statement of problem Review of relevant analyses and tests Determination of the largest ice force on an isolated structure Preliminary remarks The buckling analysis of a floating wedge Proposed method to determine Literature cited
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  • 6
    Call number: ZSP-201-76/18
    In: CRREL Report, 76-18
    Description / Table of Contents: Three surface elevation and ice thickness profiles obtained during the 1972 Arctic Ice Dynamics Joint Experiment on a multiyear ice floe were analyzed to obtain relationships between surface elevation, thickness and physical properties of the ice. It was found that for ice freeboards from 0.10 m to 1.05 m above sea level a linear relationship between ice density and freeboard could be postulated. The equation for the regression line is: Ice density = -194f' + 974 kg/cu m where f' is the ice freeboard plus snow depth in ice equivalent at the point in question. This statistical relationship is consistent with observed physical properties, which indicate that as the ice freeboard increases, ice salinity decreases and the higher freeboard or thicker ice therefore decreases in density. Using this variable density with freeboard relationship, a model was constructed to predict ice thickness, given ice freeboard and snow depth alone. This prediction is desirable, since snow depth and freeboard are relatively easy to obtain, whereas ice thickness can usually be obtained only by drilling through the ice. The model was compared with two other models. It was found that the variable density prediction model gave the best approximation to observed ice thickness, with a standard error between the measured and predicted value of about 0.4 m, compared with errors from 50 to 100% higher for the other two models.
    Type of Medium: Series available for loan
    Pages: v, 25 Seiten , Illustrationen
    Series Statement: CRREL Report 76-18
    Language: English
    Note: Contents Abstract Preface Summary Introduction Previous work Results Models for predicting thickness from ice freeboard Comparison between measured and predicted thicknesses Spectral behavior of measured and predicted profiles Comparisons of ice thickness using airborne laser profilometry Conclusions Literature cited Appendix A: Misgivings on isostatic imbalance as a mechanism for sea ice cracking
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  • 7
    Call number: ZSP-201-83/21
    In: CRREL Report, 83-21
    Description / Table of Contents: The probability density function of the gouge depths into the sediment is represented by a simple negative exponential over four decades of gouge frequency. The exceedance probability function is, therefore, e to the -lambda d, where d is the gouge depth in meters and lambda is a constant. The value of lambda shows a general decrease with increasing water depth, from 9/m in shallow water to less than 3/m in water 30 to 35 m deep. The deepest gouge observed was 3.6 m, from a sample of 20,354 gouges that have depths greater than or equal to 0.2 m. The dominant gouge orientations are usually unimodal and reasonably clustered, with the most frequent alignments roughly parallel to the general trend to the coastline. The value of N(bar) sub 1, the mean number of gouges (deeper than 0.2 m) per kilometer measured normal to the trend of the gouges, varies from 0.2 for protected lagoons to 80 in water between 20 and 38 m deep in unprotected offshore regions. The distribution of the spacings between gouges as measured along a sampling track is a negative exponential. The form of the frequency distribution of N sub 1 varies with water depth and is exponential for lagoons and shallow offshore areas, previously skewed for 10 to 20 m depths off the barrier islands, and near-normal for deeper water. As a Poisson distribution gives a reasonable fit to the N sub 1 distributions for all water depths, it is suggested that gouging can be taken as approximating a Poisson process in both space and time. The distributions of the largest values per kilometer of gouge depths, gouge widths, and the heights of the lateral embankment of sediments plowed from the gouges are also investigated.
    Type of Medium: Series available for loan
    Pages: 40 Seiten , Illustrationen, 1 Karte
    Series Statement: CRREL Report 83-21
    Language: English
    Note: CONTENTS Abstract Preface Introduction Background and environmental setting Data collection and terminology Data analysis Gouge depths Gouge orientation Gouge frequency Extreme value analysis Applications to offshore design Gouge depth Extreme value statistics Burial depths Conclusion Literature cited Appendix A: Detailed bathymetric map of the Alaskan portion of the Beaufort Sea
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  • 8
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-82/23
    In: CRREL Report, 82-23
    Description / Table of Contents: A direct filtration, water treatment pilot plant was operated on the Kenai River at Soldotna, Alaska, during the summer of 1980. The purpose of the pilot plant operations was to determine the feasibility of the direct filtration process for removal of glacial silt. The major criterion used to determine feasibility was production of water containing less than 1.0 NTU of turbidity. For the range of raw water turbidities encountered (22-34 NTU), the pilot plant testing indicated that direct filtration was feasible and could be considered as an alternative to conventional waiter treatment plants containing sedimentation tanks.
    Type of Medium: Series available for loan
    Pages: 26 Seiten , Illustrationen
    Series Statement: CRREL Report 82-23
    Language: English
    Note: CONTENTS Abstract Preface Conversion factors: U.S. customary to metric Introduction Glacial characteristics Water treatment Materials and methods Experimental design Pilot plant intake Hydrocyclone Chemical addition system Flocculation system Filtration system Pilot plant operations Coagulant chemical preparations Flow measurement Sampling Results and discussion Kenai River w ater quality Evaluation of pilot plant testing Performance of pilot plant elements Physical and chem ical variables Conclusions Recommendations Literature cited
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  • 9
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-85/5
    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.
    Type of Medium: Series available for loan
    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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  • 10
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    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-79/12
    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.
    Type of Medium: Series available for loan
    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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