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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-201-76/29
    In: CRREL Report, 76-29
    Description / Table of Contents: In order to verify current theoretical equations on ice bearing capacity, a heavily loaded truck was used to make successive passes over two ice bridges. Equipment, weather and the normal problems associated with field work resulted in only one complete breakthrough test. Breakthrough occurred on one bridge with a vehicle weight of 53,630 lb (24,327 kg) and an ice thickness of 17.5 in. (44.5 cm). Since only one test was completed, the conclusions drawn cannot be unequivocal. However, the results do indicate that Nevel's equation for ultimate failure of a floating ice sheet is a good working tool.
    Type of Medium: Series available for loan
    Pages: iv, 19 Seiten , Illustrationen
    Series Statement: CRREL Report 76-29
    Language: English
    Note: Contents Abstract Preface Summary Introduction Location Test procedure Loading Site preparation and bridge construction Deflection measurements Conclusions Literature cited Appendix, Test data
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  • 2
    Call number: ZSP-201-76/30
    In: CRREL Report, 76-30
    Description / Table of Contents: The focus of this investigation was to assess the utility of remote sensing techniques in the study of land use-water quality relationships in an east central Wisconsin test area. The following types of aerial imagery were evaluated for this purpose: high altitude (60,000 ft) color, color infrared, multispectral black and white, and thermal; low altitude (less than 5000 ft) color infrared, multispectral black and white, thermal, and passive microwave. A non-imaging hand-held four-band radiometer was evaluated for utility in providing data on suspended sediment concentrations. Land use analysis includes the development of mapping and quantification methods to obtain baseline data for comparison to water quality variables. Suspended sediment loads in streams, determined from water samples, were related to land use of dfferences and soil types in three major watersheds. A multiple correlation coefficient R of 0.85 was obtained for the relationship between the 0.6-.7 incident and reflected radiation data from the hand-held radiometer and concurrent ground measurements of suspended solids in streams. Applications of the methods and baseline data developed in this investigation include: mapping and quantification of land use; input to watershed runoff models,estimation of effects of land use changes on stream sedimentation; and remote sensing of suspended sediment content of streams. High altitude color infrared imagery was found to be the most acceptable remote sensing technique forthe mapping and measurement of land use types.
    Type of Medium: Series available for loan
    Pages: vi, 53 Seiten , Illustrationen
    Series Statement: CRREL Report 76-30
    Language: English
    Note: CONTENTS Abstract Preface Conversion factors: U.S. customary to metric (SI) units of measurement lntroduction Objectives Approach and project history Study area Physical setting Cultural setting Documented pollution sources in the study area Evaluation of imagery Photographic imagery Thermal imagery PMIS imagery Land use analysis Analysis of 1972 imagery Analysis of 1974 imagery Soils of Manitowoc, East Twin and Oconto River watersheds Manitowoc River watershed East Twin River watershed Oconto River watershed Water quality data Manitowoc River East Twin River Oconto River Land use/stream sedimentation relationships Results and conclusions Sensor evaluation Land use analysis Mapping approaches Land use/sedimentation relationships Cost effectiveness analysis Recommendations and applications Selected bibliography Appendix A. Precipitation and temperature data
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  • 3
    Call number: ZSP-201-80/10
    In: CRREL Report, 80-10
    Description / Table of Contents: A mathematical model of coupled heat and moisture flow in soils has been developed. The model includes algorithms for phase change of soil moisture and frost heave and permits several types of boundary and initial conditions. The finite element method of weighted residual (Galerkin procedure) was chosen to simulate the spatial regime and the Crank-Nicholson method was used for the time domain portion of the model. To facilitate evaluation of the model, the heat and moisture fluxes were essentially decoupled; moisture flux was then simulated accurately, as were heat flux and frost heave in a laboratory test. Comparison of the simulated and experimental data illustrates the importance of unsaturated hydraulic conductivity. It is one parameter which is difficult to measure and for which only a few laboratory test results are available. Therefore, unsaturated hydraulic conductivities calculated in the computer model may be a significant source of error in calculations of frost heave. The algorithm incorporating effects of surcharge and overburden was inconclusively evaluated. Time-dependent frost penetration and frost heave in laboratory specimens were closely simulated with the model. After 10 days of simulation, the computed frost heave was about 2.3 cm vs 2.0 cm and 2.8 cm in two tests. Frost penetration was computed as 15 cm and was measured at 12.0 cm and 12.2 cm in the two laboratory samples after 10 days.
    Type of Medium: Series available for loan
    Pages: v, 49 Seiten , Illustrationen
    Series Statement: CRREL Report 80-10
    Language: English
    Note: CONTENTS Abstract Preface Introduction One-dimensional equations of simultaneous heat and moisture flux Moisture transport Heat transport Phase change Coupling effects Frost heave algorithm Development of computer model Finite difference vs finite element method Finite element formulation Time domain solution Evaluation of the mathematical model Heat flux Moisture flux Numerical dispersion Frost heave of homogeneous laboratory samples Conclusions Recommended studies to refine the model Literature cited Appendix A. Work plan, staffing and instrumentation requirements for correlating results oflaboratory frost susceptibility tests with field performance Appendix B. Proposed investigation of thaw weakening of subgrade soil and granular unboundbase course Appendix C. Derivation of finite element system matrices
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  • 4
    Call number: ZSP-201-86/11
    In: CRREL Report, 86-11
    Description / Table of Contents: This initial study of the ice-covered Tanana River, near Fairbanks, Alaska, attempted to 1) establish field methods for systematic and repetitive quantitative analyses of an ice-covered river's regime, 2) evaluate the instruments and equipment for sampling, and 3) obtain the initial data of a long-term study of ice cover effects on the morphology, hydraulics and sediment transport of a braided river. A methodology was established, and detailed measurements and samplings, including profiling by geophysical techniques, were conducted along cross sections of the river. A small, portable rotary drill rig equipped with a 356-mm (14-in.) ice auger was used to cut large diameter holes in the ice cover for through-the-ice measurements. Portable heat sources and a heated shelter were required to continuously thaw and dry equipment for the repetitive measurements. Measurements included ice cover thickness, water level, water depth, temperature, flow velocity, suspended load and bed load, frazil ice distribution and bed material composition. Remotely gathered data included apparent resistivity and subsurface radar profiling. The various techniques, sampling gear and problems encountered during use in the subfreezing cold are described in detail in this report.
    Type of Medium: Series available for loan
    Pages: v, 49 Seiten , Illustrationen
    Series Statement: CRREL Report 86-11
    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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  • 5
    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.
    Type of Medium: Series available for loan
    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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  • 6
    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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  • 7
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-87/13
    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.
    Type of Medium: Series available for loan
    Pages: ii, 16 Seiten , Illustrationen
    Series Statement: CRREL Report 87-13
    Language: English
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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-201-87/10
    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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  • 9
    Call number: ZSP-201-84/16
    In: CRREL Report, 84-16
    Description / Table of Contents: Phase composition curves are presented for a typical saline silt from Lanzhou, P.R.C., and compared to some silts from Alaska. The unfrozen water content of the Chinese silt is much higher than that of the Alaskan silts due to the large amount of soluble salts present in the silts from China, which are not present in silt from interior Alaska. When the salt is removed, the unfrozen water content is then similar for both the Chinese and Alaskan silt. Here we introduce a technique for correcting the unfrozen water content of partially frozen soils due to high salt concentrations. We calculate the equivalent molality of the salts in the unfrozen water at various temperatures from a measurement of the electrical conductivity of the extract from saturated paste.
    Type of Medium: Series available for loan
    Pages: iii, 25 Seiten , Illustrationen
    Series Statement: CRREL Report 84-16
    Language: English
    Note: Contents Abstract Preface Introduction Background Materials Sample preparation Nuclear magnetic resonance Specific surface area Electrical conductivity Results and discussion Summary Literature cited Appendix A: Unfrozen water content vs temperature data for Lanzhou silt
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  • 10
    Call number: ZSP-201-82/37
    In: CRREL Report, 82-37
    Description / Table of Contents: This report presents a Landsat-derived land cover map of the northwest portion of the Arctic National Wildlife Refuge, Alaska. The report is divided into two parts. The first is devoted to the land cover map with detailed descriptions of the mapping methods and legend. The second part is a description of the study area. The classification system used for the maps is an improvement over existing methods of describing tundra vegetation. It is a comprehensive method of nomenclature that consistently applies the same criteria for all vegetation units. It is applicable for large- and small-scale mapping and is suitable for describing vegetation complexes, which are common in the patterned-ground terrain of the Alaskan Arctic. The system is applicable to Landsat-derived land cover classifications. The description of the study area focuses on five primary terrain types: flat thaw-lake plains, hilly coastal plains, foothills, mountainous terrain, and river flood plains. Topography, landforms, soils and vegetation are described for each terrain type. The report also contains area summaries for the Landsat-derived map categories. The area summaries are generated for the five terrain types and for the 89 townships within the study areas. Two land cover maps at 1:250,000 are included.
    Type of Medium: Series available for loan
    Pages: 68 Seiten , Illustrationen, 2 Karten
    Series Statement: CRREL Report 82-37
    Language: English
    Note: CONTENTS Abstract Preface Foreword Introduction A land cover map of the ANWR study area Legend development Mapping method Results Discussion Description of the ANWR study area General description Description of specific terrain types Conclusions Literature cited Appendix A: Descriptions of Landsat land cover categories for ANWR Appendix B: Area summaries Appendix C: Aproximate equivalent units in several systems of land cover, wetland and vegetation classifications used in northern Alaska Appendix D: Soil taxonomy Appendix E: Summary of principal Landsat land cover categories within the terrain types of the ANWR study area
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