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  • 1975-1979  (1,920)
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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-202-345
    In: Research report / Cold Regions Research and Engineering Laboratory, 345
    Description / Table of Contents: CONTENTS: Abstract. - Preface. - List of symbols. - Introduction. - Previous work. - Experimental design. - The radioisotope 22Na. - Description of apparatus. - Experimental procedure. - Correction of profiles. - Assumptions. - Decay correction. - Boundary correction. - Error analysis. - Results. - Salinity data. - Temperature data. - Growth velocity. - Discussion. - Brine and ice properties. - Brine salinity. - Brine density. - Brine volume. - Brine latent heat of freezing. - Brine viscosity, specific heat, and thermal conductivity. - Ice properties. - Theoretical brine expulsion model. - Continuity equations. - Thermal energy equation. - Simplified brine expulsion equations. - Brine expulsion in NaCl ice. - Results. - Discussion. - Gravity drainage in NaCl ice. - Application of results to natural sea ice. - Effective distribution coefficient. - Previous work. - Experimental procedure and results. - Conclusions. - Literature cited. - Appendix A: Profile correction data. - Appendix B: Program "correct" and sample output. - Appendix C: Tabulation of salinity data. - Appendix D: Tabulation of profile data. - Appendix E: Time-ice thickness equations (Runs 2 and 3). - Appendix F: Tabulation of distribution coefficient data.
    Description / Table of Contents: To obtain a better understanding of the desalination of natural sea ice, an experimental technique was developed to measure sequential salinity profiles of a growing sodium chloride ice sheet. Using radioactive 22Na as a tracer, it was possible to determine both the concentration and movement of the brine within the ice without destroying the sample. A detailed temperature and growth history of the ice was also maintained so that the variation of the salinity profiles could be properly interpreted. Since the experimental salinity profile represented a smoothed, rather than a true salinity distribution, a deconvolution method was devised to restore the true salinity profile. This was achieved without any significant loss of end points. In all respects, the salinity profiles are similar to those of natural sea ice. They have a characteristic C-shape, and clearly exhibit the effects of brine drainage. Not knowing the rates of brine expulsion or gravity drainage, the variation of the salinity profiles during the period of ice growth could be explained by either process. To determine the relative importance of the desalination mechanisms, a theoretical brine expulsion model was derived and compared to the experimental data. As input for the model, equations describing the variation of some properties of NaCl brine with temperature were derived. These included the brine salinity, viscosity, specific heat, thermal conductivity, and latent heat of freezing. The theoretical brine expulsion model was derived by performing mass and energy balances over a control volume of NaCl ice. A simplified form of the model, when compared to the experimental results, indicated that brine expulsion was only important during the first several hours of ice growth, and later became a minor desalination process relative to gravity drainage which continued to be the dominant mechanism for the remainder of the study period (up to 6 weeks). The rate of gravity drainage was found to be dependent on the brine volume and the temperature gradient of the ice. As either the brine volume or temperature gradient was increased, the rate of change of salinity due to gravity drainage increased. The equation commonly used to calculate the effective distribution coefficient (Weeks and Lofgren 1967) was modified and improved by taking brine drainage into account. An expression was also derived to give the distribution coefficient at very low growth velocities.
    Type of Medium: Series available for loan
    Pages: vii, 85 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 345
    Language: English
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  • 2
    Series available for loan
    Series available for loan
    Hanover, N.H. : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-202-349
    In: Research report / Cold Regions Research and Engineering Laboratory, 349
    Description / Table of Contents: CONTENTS: Abstract. - Preface. - Introduction. - Test locations. - Post Pond. - Mascoma Lake. - Winter freeze-up. - Ice cover properties. - Stratigraphy. - Microstructure. - Porosity. - Impurity content. - Flexural strength. - Test sites. - Beam test procedure. - Beam dimensions. - Beam temperatures. - Beam strengths. - Results. - Post Pond, Site PB, 12 February 1974. - Post Pond, Site PC, 21 February 1974. - Mascoma Lake, Site MD, 25 February 1974. - Mascoma Lake, Site MD, 26 February 1974. - Mascoma Lake, Site MD, 1 March 1974. - Post Pond, Site PA, 4 March 1974. - Post Pond, Site PA, 7 March 1974. - Post Pond, Site PA, 8 March 1974. - Post Pond, Site PB, 12 March 1974. - Post Pond, Midway between Sites PB and PC, 15 March 1974. - Post Pond, Midway between Sites PA and PB, 26 March 1974. - Post Pond, Midway between Sites PA and PB, 29 March 1974. - Post Pond, Midway between Sites PA and PB, 3 April 1974. - Conclusions. - Literature cited.
    Description / Table of Contents: In-place cantilever beam tests on Post Pond and Mascoma Lake ice yielded a maximum flexural strength of 7.1 kg/cm^2. The minimum strength, unrelated to failure along pre-existing cracks in the ice, was 2.9 kg/cm^2. The majority of tests were performed in the push-down mode after it was discovered that beams tested in the pull-up mode, which places the bottom surface in tension, frequently broke prematurely along cracks in the bottom of the ice. Premature failures of this kind usually occurred at stresses of 2-3 kg/cm^2. Data further demonstrate that the intrinsic strength of lake ice decreases significantly as the surface air temperature goes to 0°C. Ice that has just become isothermal, but has not yet begun to candle, has a strength of about 4 kg/cm^2; ice that has been subjected to prolonged periods of above-freezing air temperatures generally fails at about 3 kg/cm^2. Tests also show that cold unrecrystallized snow-ice is as strong as the underlying lake ice. Tests of the effect of crystalline structure indicate that ice composed of crystals with their c-axes horizontal is measurably stronger than ice in which the crystals are oriented with their c-axes vertical.
    Type of Medium: Series available for loan
    Pages: v, 28 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 349
    Language: English
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  • 3
    Call number: ZSP-202-344
    In: Research report
    Description / Table of Contents: CONTENTS: Abstract. - Preface. - Introduction. - Approach and methods. - Results. - Lake morphology. - Elongation. - Orientation. - Percentage cover (density). - Lake classification. - L1 unit. - L2 unit. - L3 unit. - L4 unit. - L5 and Lu units. - Other units. - Lake basin depths. - Ice volume and basin genesis. - Geological implications. - Conclusions. - Selected bibliography.
    Description / Table of Contents: The lakes of the Arctic Coastal Plain of northern Alaska were classified, based on size, shape, orientation and distribution, into six lake units and three nonlake units. Regional slope and relief were demonstrated to control lake size, the largest lakes occurring on the flattest, northernmost segment of the Coastal Plain. Using ERTS-1 sequential imagery and existing photography and data, lakes were grouped according to three depth ranges, 〈 1 m, 1-2 m and 〉 2 m. Deepest lakes have the longest period of summer ice cover. Ice on shallow lakes melts the earliest. Maximum depths of lakes were computed based on ice volume content of the perennially frozen ground (permafrost) and these agreed with observed values and ranges. The lake classification and regional ERTS-1 coverage also appear to provide additional information on the limits of late-Pleistocene transgressions on the Coastal Plain.
    Type of Medium: Series available for loan
    Pages: iv, 21 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 344
    Language: English
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  • 4
    Call number: ZSP-202-337
    In: Research report
    Description / Table of Contents: Contents: Introduction. - Surface ice observations. - Imagery interpretation. - Side-looking airborne radar. - Infrared. - Conclusions. - Literature cited.
    Description / Table of Contents: Ice conditions during mid-January 1974 in the Gulf of St. Lawrence and in the estuaty as far upstream as Rimouski are described utilitizing side-looking airborne radar, infrared and photographic imagery. The interpretations were verified by simultaneous surface observations on the ice by investigators operating from the CSS Dawson. The ice examined was undergoing rapid drift and deformation and showed a wide variety of thin ice (0-40 cm) features formed under the influence of strong winds and currents. These observations should serve as a guide in interpreting ice conditions in similar areas where ground truth data are not available.
    Type of Medium: Series available for loan
    Pages: 41 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 337
    Language: English
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  • 5
    Call number: ZSP-201-76/8
    In: CRREL Report, 76-8
    Description / Table of Contents: During the past decade a number of methods for measuring the amount of unfrozen water in partially frozen ground have emerged. Means of quickly and simply predicting unfrozen water contents in clay have become increasingly important with the growth of interest in encapsulating clay soils compacted at low water contents to serve as base courses for roads. Unfortunately the measurements require sophisticated equipment and, in most instances, specially trained operators. In an effort to simplify the task of obtaining water-ice phase composition data, methods of calculating phase composition curves from other, simpler measurements on soils have been sought. The paper presents a method of deriving the measurement of unfrozen water contents at various temperatures from liquid limit determinations.
    Type of Medium: Series available for loan
    Pages: iv, 9 Seiten , Illustrationen
    Series Statement: CRREL Report 76-8
    Language: English
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  • 6
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-76/9
    In: CRREL Report, 76-9
    Description / Table of Contents: Access to study areas may be an important factor in long-term field-oriented research, particularly in-regions without well-developed road and communications systems. In a wildland hydrometeorology research project in subarctic Alaska, access to and within a 40-square-mile research watershed has been developed both in accordance with a general plan prepared at project inception and in response to developing research requirements. Foot trails, trails for 'off-road' low-ground-pressure tracked vehicles, helicopter transport, long-term data recorders, and radio telemetry of data have all been incorporated in an access and communications system. Cost estimates indicate that incorporation of gravel roads into the system would be economically advantageous, given adequate funding for initial road construction.
    Type of Medium: Series available for loan
    Pages: iv, 9 Seiten , Illustrationen
    Series Statement: CRREL Report 76-9
    Language: English
    Note: Contents Abstract Preface Conversion factors for U.S. customary and SI units Introduction Access within the Caribou-Poker Creeks Research Watershed Trail access Helicopter access Road access Alternative approaches Long-term recorders Telemetry systems Remote sensing Relative costs A desirable system Selected bibliography
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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-201-76/10
    In: CRREL Report, 76-10
    Type of Medium: Series available for loan
    Pages: vi, 25 Seiten , Illustrationen
    Series Statement: CRREL Report 76-10
    Language: English
    Note: CONTENTS Introduction Experimental work SCR samples CAG samples CMS samples UAG samples SI samples Optical system Equipment Procedure Photographic work Large cracks and fissures Small damage to the surface Small damage to the buIk Results Damage as a function of the position x of the focal point; n(x) Damage as a function of the number of irradiations #; n(#) Damage as a function of crystallographic orientation ĉ; n (ĉ); p (ĉ) Damage as a function of surface structure Damage as a function of age A; n (A) Damage as a function of wavelength λ; p(λ) Systematic study of damage as a function of W, t, m and s; n(W, t, m, s) Analysis Fracture in ice Mechanisms for optically generated damage in transparent dielectrics Discussion of the results Summary and conclusions Literature cited
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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-201-76/11
    In: CRREL Report, 76-11
    Description / Table of Contents: Water flow through the unsaturated portion of a snowpack is calculated using various assumptions about radiation penetration into the snow. The results show that for the purposes of hydrologic forecasting, it is sufficiently ac­curate to assume that all of the radiation absorption occurs at the surface. The error in the calculation of flow is largest for very shallow snowpacks, but this error is reduced by radiation absorption at the base of the snow and by the routing of meltwater through the saturated basal layer.
    Type of Medium: Series available for loan
    Pages: v, 9 Seiten , Illustrationen
    Series Statement: CRREL Report 76-11
    Language: English
    Note: CONTENTS Abstract Preface Summary Conversion factors for U.S. customary and SI units Introduction Theory Examples Discussion 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-201-76/12
    In: CRREL Report, 76-12
    Description / Table of Contents: The heat transfer processes associated with melting and refreezing a drill hole 500 m in depth and 0.150 m in initial radius through an ice shelf were approximately analyzed. The results were expressed in graphical form showing the time available for experimentation under the hole as a function of heating duration and heating strength. It was found that the refreezing of the drill hole had a much slower rate than the melting of the hole.
    Type of Medium: Series available for loan
    Pages: vi, 15 Seiten , Illustrationen
    Series Statement: CRREL Report 76-12
    Language: English
    Note: Contents Abstract Preface Summary Nomenclature Introduction Analysis Melting period Freezing period Calculation Conclusion Literature cited Appendix A: Justification of using eq 8 for the calculation of heat transfer coefficient h
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  • 10
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-76/13
    In: CRREL Report, 76-13
    Description / Table of Contents: The thermal structure and ice conditions of Lake Champlain, a mid-latitude large lake, near Shelburne Point, Vermont, were studied during the winter of 1974-75. The lake was instrumented to a depth of 8.5 m with a string of highly calibrated thermistors, connected to a data logger on shore which recorded water temperatures every four hours. An ice mooring system was developed to anchor the thermistor string so that ice and water temperatures could be obtained at known levels. This temperature recording system measured vertical and horizontal variations in ice and water temperature regimes during ice formation, growth and decay. Meteorological data were measured during the winter period November 1974 through March 1975 at the site. Ice stratigraphy was determined for the ice at the site at its maximum seasonal growth for comparison with ice from St. Albans Bay (at the northern end of Lake Champlain) which had formed earlier. Correlations were determined between ice growth and accumulated degree days of freezing. The operation of a bubbler system installed near the measurement site around a service dock was observed.
    Type of Medium: Series available for loan
    Pages: vii, 22 Seiten , Illustrationen
    Series Statement: CRREL Report 76-13
    Language: English
    Note: CONTENTS Abstract Preface Summary Introduction Climate Site selection Instrumentation, measurements and calibration Installation of automatic water temperature recording system Visual observations and ice structure St. Albans Shelburne Analysis Temperature comparison Water temperature measuring system Changes in water temperature Wind Degree-days of freezing Prediction of ice formation Bubbler system Conclusions Recommendations Literature cited
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