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  • Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory  (26)
  • Arizona Board of Regents  (25)
  • Amsterdam : Elsevier
  • Leiden : Rijksmuseum van Geologie en Mineralogie
  • English  (63)
  • 1
    Call number: ZSP-202-315
    In: Research report
    Description / Table of Contents: CONTENTS: Preface. - Introduction. - Part 1:Mesoscale strain measurements on the Beaufort Sea pack ice. - Abstract. - Introduction. - Previous work. - Site location. - Results. - Correlation of synoptic aerial photography with measured strains. - Correlation of estimated wind stress and strain. - Conclusions. - Literature cited. - Part II: Structure of a multiyear pressure ridge. - Abstract. - Introduction. - Profiles. - Internal properties. - Largest ridge sail. - Conclusions. - Literature cited. - Part III: Top and bottom roughness of a multiyear ice floe. - Abstract. - Introduction. - Results. - Literature cited. - Part IV:Airphoto analysis of ice deformation in the Beaufort Sea Abstract. - Introduction. - Study area. - Method of analysis. - Ice deformations. - Net deformational changes. - Pressure ridge distribution. - Summary and conclusions. - Literature cited. - Part V: Data on morphological and physical characteristics of sea ice in the Beaufort Sea.
    Description / Table of Contents: Mesoscale strain measurements on the Beaufort Sea pack ice; Structure of a multiyear pressure ridge; Top and bottom roughness of a multiyear ice floe; Airphoto analysis of ice deformation in the Beaufort Sea; Data on morphological and physical characteristics of sea ice in the Beaufort Sea.
    Type of Medium: Series available for loan
    Pages: iii, 66 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 315
    Language: English
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  • 2
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    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    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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    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    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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  • 4
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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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  • 5
    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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  • 6
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    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    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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  • 7
    Call number: AWI S2-92-0441 ; AWI G2-95-0239
    In: Developments in atmospheric science ; 17, Volume 17
    Type of Medium: Monograph available for loan
    Pages: XVIII, 425 Seiten , Illustrationen
    ISBN: 0444430148
    Series Statement: Developments in atmospheric science 17
    Language: English
    Note: Contents: List of Figures. - List of Tables. - 1. Introduction. - a. An Overview of Principal Component Analysis (PCA). - b. Outline of the Book. - c. A Brief History of PCA. - d. Acknowledgments. - 2. Algebraic Foundations of PCA. - a. Introductory Example: Bivariate Data Sets. - Monterey, California air temperatures. - Centering and rotating the data set. - Variances in the rotated frame. - Principal angles. - Principal variances. - Principal covariance. - Principal directions. - Principal components; principal directions as basis vectors. - Matrix representation. - The PCA property. - Invariance of the total variance under rotation. - Principal variances for standardized data sets. - PCA and estimates of the statistical parameters of normal populations. - PCA and the construction of Monte Carlo experiments. - Eigenvalues and eigenvectors of the covariance and scatter matrices. - b. Principal Component Analysis: Real-valued Scalar Fields. - t-centering the data set. - The scatter probe and the scatter matrix. - The eigenstructures of PCA. - The basic data set representations; analysis and synthesis formulas. - The PCA property. - Second-order properties of PCA; the total scatter . - The singular value decomposition (SVD) of a data set. - Second-order properties of PCA; correlations. - PCA characterized by the PCA property. - The asymptotic PCA property and dynamical systems. - PCA of spatial composites of data sets. - PCA of temporal composites of data sets. - c. Principal Component Analysis: Complex-valued Scalar Fields, and Beyond. - PCA of complex-valued data sets (C-PCA). - Complex algebra conventions. - The scatter probe and scatter matrix for C-PCA. - Derivation of the eigenstructures of C-PCA. - The fundamental formulas of C-PCA. - Generalization of PCA to quaternion-valued data sets (Q-PCA). - Matrix representations of complex and quaternion numbers. - PCA of matrix-valued data sets (M-PCA). - Reduction of M-PCA to C-PCA form. - d. Bibliographic Notes and Miscellaneous Topics. - Alternate interpretation of the scatter probe. - Numerical calculations of eigenstructures of a scatter matrix. - Some elementary properties of eigenstructures of a scatter matrix. - Sample space vs. state space: choosing the dual computation. - PCA for continuous domains. - PCA for continuous domains: the viewpoint of empirical orthogonal functions. - The sixteen possible domain pairs for PCA: abstract PCA. - 3. Dynamical Origins of PCA. - a. One-dimensional Hannonic Motion. - A spring-linked-mass model; general form. - A spring-linked-mass model; special form. - A numerical example of the asymptotic PCA property. - Further investigations of the asymptotic PCA property and of EOF's. - b. Two-dimensional Wave Motion. - Solution of a two-dimensional damped-wave model. - Demonstration of the asymptotic PCA property (forcing and friction absent). - Demonstration of the asymptotic PCA property (forcing and friction present). - Physical basis for eigenframe rotations. - c. Dynamical Origins of Linear Regression (LR). - From continuous to discrete solutions to the regression model. - The linear regression procedure. - Comparison of LRA and PCA. - d. Random Processes and Karhunen-Loeve Analysis. - Origins of random processes in linear settings. - Karhunen-Loeve representation of random data sets and comparison with PCA. - e. Stationary Processes and PCA. - Derivation of the PCA representation of a one-dimensional stationary process via a simple wave model. - Connections between PCA and stationary processes: the case of one dimension. - Connections between PGA and stationary processes: extension to two dimensions. - f. Bibliographic Notes. - 4. Extensions of PCA to Multivariate Fields. - a. Categories of Data and Modes of Analysis. - Examples. - Generalized notation: the concepts of "individual" and "variable" in PCA. - b. Local PCA of a General Vector Field. - The PCA formalism. - Squared correlations. - Variational origin of the scatter matrix. - Examples. - c. Global PCA of a General Vector Field: Time-Modulation Form. - The PGA formalism. - Squared correlations. - Degeneracy of global PGA to local PGA. - Variational origin of the scatter matrix. - d. Global PCA of a General Vector Field: Space-Modulation Form. - The PCA formalism. - Squared correlations. - Variational origin of the scatter matrix. - e. PCA of Spectral Components of a General Vector Field. - Fourier analysis of the vector field components. - The scatter matrix in the spectral setting. - Example of spectral PCA of a windfield. - f. Bibliographic Notes and Miscellaneous Topics. - The eight modes of analysis and Cattell's classifications. - Time-modulation PGA as a special case of matrix-valued PGA. - Applications to the PGA of wind fields. - Distinction between time-modulation PGA and complex PGA. - Applications to the PGA of storm tracks. - 5. Selection Rules for PCA. - a. Random Reference Data Sets. - b. Dynamical Origins of the Dominant-Variance Selection Rules. - A dynamical model. - Rationale for selection rules. - c. Rule A4. - Statistical basis and discussion. - Choice of λ0. - d. Rule N . - Statistical basis and discussion. - Adjustments for correlated data: effective sample size. - Asymptotic eigenvalues for large data sets. - e. Rule M. - f. Comments on Dominant-Variance Rules . - g. Dynamical Origins of the Time-History Selection Rules. - h. Rule KS2. - The white spectrum and the cumulative periodogram. - Statement of Rule KS2. - i. Rules AMPλ. - Fisher's test. - Siegel's test. - Statement of Rules AMPλ. - j. Rule Q. - k. Selection Rules for Vector-Valued Fields. - Local PCA rules. - Global PCA (time-modulated) rules. - Global PCA (space-modulated) rules. - I. A Space-map Selection Rule. - Canonic direction angles. - Differential relations between unit vectors and canonic direction angles. - An r-tile metric for comparing canonic direction angles. - Statistical aspects: critical values for class errors. - Statement of the selection rule. - m. Bibliographic Notes and Miscellaneous Topics. - Puzzles and problems underlying Rule N; the logarithmic eigenvalue curve. - Numerical intractability of the classical formulas for the eigenvalues of a random matrix. - Monte Carlo approaches to the eigenvalue distribution problem. - Comparison of Monte Carlo methods and asymptotic formulas for eigenvalue distributions. - The problem of closely spaced eigenvalues; tests for equal eigenvalues. - The generalized basis for dominant variance selection rules. - Parallel work in atomic physics. - 6. Factor Analysis (FA) and PCA. - a. Comparison of PCA, LRA, and FA. - Similarities between PCA, LRA, and FA. - Dissimilarities between PCA, LRA, and FA. - The usual algebraic form of FA; its PC and LR interpretations. - b. The Central Problems of FA. - The matrix formulation of FA. - The detailed sub-problems of FA. - c. Bibliographic Notes. - The selection rule problem in FA. - The parameter estimation problem in FA. - 7. Diagnostic Procedures via PCA and FA. - a. Dual Interpretations of a Data Set: State Space and Sample Space. - b. Interpreting E-frames in PCA State Space. - Example: graphical display of eigenvectors. - Rationales for interpreting eigenmaps and time series. - PCA as a means, rather than an end. - c. Informative and Uninformative E-frames in PCA State Space. - d. Rotating E-frames in PCA State Space (varimax). - A two-dimensional example of the varimax procedure. - The general varimax procedure. - The loss of the PCA property for rotated E-frames. - e. Projections onto E-frames in PCA State Space (procrustes). - Derivation of the procrustes technique. - Some observations on the generality of the procrustes technique. - f. Interpreting A-frames in PCA Sample Space. - g. Rotating A-frames in PCA Sample Space (varimax). - h. Projections onto A-frames in PCA Sample Space (procrustes). - i. Detecting Clusters of Points in PCA State or Sample Spaces. - Minimal spanning trees. - Defining cluster pairs, and te
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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-202-314
    In: Research report
    Description / Table of Contents: CONTENTS: Introduction. - Previous work. - Sea ice terrain model. - Traffic ability model. - Analytic calculation of DT/DSL. - Monte Carlo calculation. - Results of traffic ability computations. - Experimental traffic ability ratios using ridge overlays. - Regional variations in ridging intensity. - Additional traffic ability aspects of sea ice. - Shear zone and rubble fields. - Linear lead systems. - Conclusions. - Literature cited. - Appendix A. Distribution of the lateral extent of ridges. - Abstract.
    Description / Table of Contents: A sea ice terrain model, based upon previously tested height and spacing distributions for sea ice pressure ridging, is developed. Using this model, and additional information on pressure ridge extents, a trafficability model for vehicles traversing the pack ice is developed. Both analytic and Monte Carlo calculations of vehicle trafficability, measured in terms of the average ratio of the total distance traveled over a straight-line distance, are performed. The calculations include cul-de-sacs due to ridge intersections. The trafficability ratio is given as a function of ridge-height-clearance ability of the vehicle and of ridging parameters which may be obtained from laser profiles of the arctic pack ice. Results are in good agreement with simulated routes through sea ice terrain taken from aerial photo mosaics. Contour plots of ridging parameters taken from laser profilometry are also supplied. These plots, together with the trafficability model, supply mobility information for the whole of the western portion of the Arctic Basin.
    Type of Medium: Series available for loan
    Pages: iii, 21 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 314
    Language: English
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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-201-85/5
    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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    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    Call number: ZSP-201-82/31
    In: CRREL Report, 82-31
    Description / Table of Contents: Information on sea ice conditions in the Bering Strait and the icefoot formation around Fairway Rock, located in the strait, is presented. Cross-sectional profiles of Fairway Rock and the relief of the icefoot are given along with theoretical analyses of the possible forces active during icefoot formation. It is shown that the ice cover most likely fails in flexure as opposed to crushing or buckling, as the former requires less force. Field observations reveal that the Fairway Rock icefoot is massive, with ridges up to 15 m high, a seaward face only 20 degrees from vertical, and interior ridge slopes averaging 33 degrees. The icefoot is believed to be grounded and its width ranges from less than 10 to over 100 m.
    Type of Medium: Series available for loan
    Pages: 44 Seiten , Illustrationen
    Series Statement: CRREL Report 82-31
    Language: English
    Note: CONTENTS Abstract Preface Introduction Bering Strait Field reconnaissance Estimation of ice forces on Fairway Rock 1. Creep deformation 2. Crushing failure 3. Flexural failure 4. Forces required to form floating or grounded pressure ridges along therock or to pile ice on the beaches 5. Buckling failure Driving forces Angle of internal friction of sea ice Summary Literature cited Appendix A: April 1982 field observations at Fairway Rock
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