ALBERT

Beschreibung / Inhaltsverzeichnis: During the winter of 1973 - 74 a mobile infrared thermography system was used to survey the USA CRREL building at Hanover, New Hampshire. This report provides a description of excessive heat losses at several locations around the building. This report also discusses the need to carefully monitor meteorological conditions before starting a survey of a building exterior to determine if solar radiation decay from the building surface might interfere with thermographic analysis by masking the heat emanating from within the building.

Beschreibung / Inhaltsverzeichnis: 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.

Beschreibung / Inhaltsverzeichnis: 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.

Beschreibung / Inhaltsverzeichnis: CONTENTS: Abstract. - Preface. - Nomenclature. - Introduction. - Theory. - Application. - Literature cited. - Appendix.

Beschreibung / Inhaltsverzeichnis: The equations describing water movement in a dry snow cover are derived and examples of flow through ripe, refrozen and fresh snows are given. The grain size of snow has a large effect on the timing of water discharge. Water is retained by dry snow to raise its temperature and satisfy the irreducible water saturation. These requirements delay and reduce runoff following rain on dry snow.

Beschreibung / Inhaltsverzeichnis: CONTENTS: Abstract. - Preface. - Introduction. - Analytical procedures. - Thick section analysis. - Measurements of inclusion pressure. - Gas volume measurements. - Density and porosity measurements. - Results and discussion. - Sizes, shapes and distributions of bubbles. - Sizes, shapes and distributions of cavities. - Inclusion abundances. - Gas pressures in bubbles and cavities. - Total gas content. - Case for lattice diffusion. - Literature cited.

Beschreibung / Inhaltsverzeichnis: Cores obtained to the bottom of the Antarctic Ice Sheet at Byrd Station were used to analyze the physical properties of air bubbles trapped in the ice. These bubbles originate as pockets of air in the upper layers of snow and approximately 10 ml of air/100 cm^3 of ice; i.e., 10% by volume is retained permanently when the snow transforms into ice. Parameters measured were the sizes, shapes, abundances, spatial distributions, gas volumes and pressures of bubbles, and their variations with depth in the ice sheet. Bubbles occur abundantly in the top 800 m of ice but then gradually disappear until they can no longer be detected optically below 1100 m. This disappearance is not accompanied by any significant loss of air from the ice and all available evidence indicates that the air actually diffuses into the ice in response to increasing overburden pressure. The possibility exists that the dissolved gases are retained in the form of a gas hydrate or clathrate which, because of release of confining pressures, begins to decompose soon after ice cores are pulled to the surface. This decomposition is accompanied by the growth of gas-filled bubble-like cavities, and as much as 40% of the dissolved air has exsolved already from some cores in the space of less than three years. Bubble pressure measurements show that 1) bubbles with pressures exceeding about 16 bars begin to relax back to this value soon after in situ pressures are relieved by drilling, 2) further slow decompression occurs with time, and 3) the rate of decompression is controlled to some extent by the intrinsic structural properties of the ice and its thermal and deformational history. Only small variations were observed in the entrapped air content of the ice cores; they probably reflect variations in the temperature and/or pressure of the air at the time of its entrapment, but the data are not sufficient to draw any firm conclusions regarding past variations in ice sheet thickness. Only ice from the bottom 4.83 m was found to lack any detectable trace of air. Since this absence of air coincided precisely with the first appearance of stratified moraine in the cores, it is concluded that this ice originated from the refreezing of air-depleted water produced under pressure melting conditions at the bottom of the ice sheet.

Beschreibung / Inhaltsverzeichnis: Contents: Introduction. - Surface ice observations. - Imagery interpretation. - Side-looking airborne radar. - Infrared. - Conclusions. - Literature cited.

Beschreibung / Inhaltsverzeichnis: 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.

Beschreibung / Inhaltsverzeichnis: CONTENTS: Abstract. - Preface. - Introduction. - Discussion of heat loss survey of six housing units. - Survey of base facilities. - Conclusions. - Literature cited.

Beschreibung / Inhaltsverzeichnis: During the winter of 1973-74 a mobile infrared thermography system was used to survey housing units and base facilities at Pease Air Force Base, Portsmouth, New Hampshire. This report provides both qualitative and quantitative evidence regarding heat flow out of the eave vents of these housing units. Calculations indicate that a significant amount of heat is being lost in this manner due to inadequate attic (cap) insulation. Possible evidence of incomplete ventilation could explain the presence of condensation in the housing units. Analyses of thermograms are presented to show the possible existence of low and high pressure areas around a structure and how they relate to heat loss.

Beschreibung / Inhaltsverzeichnis: CONTENTS: Preface. - Introduction. - An overview of the model structure and operation. - Operation of subroutines. - TSTART. - FOMO. - REAWEA. - SEARCH. - STEMP. - TUNPIC. - Development history of the simulator. - The simulation of snow fence effects. - Urbanization and meltout. - Conclusion. - Literature cited. - Appendix A: Mathematical notation. - Appendix B: Computerprogram. - Abstract.

Beschreibung / Inhaltsverzeichnis: An annual snow-soil simulator for Arctic tundra was developed using coupled models of surface equilibrium temperature and substrate thermal diffusion. Snow ripening, melt and accumulation are modeled in the simulator which is forced with daily weather data. The simulator predicts that a snow fence array capable of producing drift deeper than 4.2 meters will initiate a permanent snowfield at Barrow, Alaska. Such a man-induced snowfield could serve as a reliable source of fresh water for Barrow and similar villages in the North Slope region of Alaska. Further analysis indicated that albedo reduction due to dust fall, snow removal, etc., is dominant over aerodynamic effects in producing the early spring meltout observed at Barrow Village.

Beschreibung / Inhaltsverzeichnis: 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.

Beschreibung / Inhaltsverzeichnis: 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.

Beschreibung / Inhaltsverzeichnis: 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.

Beschreibung / Inhaltsverzeichnis: 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.

Beschreibung / Inhaltsverzeichnis: CONTENTS: Abstract. - Preface. - Introduction. - Samples. - Collection. - Preparation. - Analytical methods. - Cations. - Lead, silicon and aluminum. - Sulfate. - Comparative analyses. - Results and discussion. - Sea salt and terrestrial dust. - Sulfate. - Lead. - Summary and conclusions. - Literature cited. - Appendix A. Concentrations of chemical constituents in Dye 3 snow and ice strata.

Beschreibung / Inhaltsverzeichnis: Concentrations of sodium, potassium, magnesium, calcium, silicon, aluminum, lead and sulfate were measured in surface snow and in individual annual accumulation layers from a 373-m-deep ice core from Dye 3, Greenland, covering the time period from 1232 to 1971 A.D. Average background (pre-1840) concentrations in micrograms/liter are: Na, 12.9 ± 9.3; K, 2.2 ± 2.1; Mg, 1.5 ± 1.0; Ca, 4.8 ± 2.4; Si, 12 ± 6; Al, 3.3 ± 1.4; Pb, 0.07 ± 0.06; and SO4, 56 ± 22. Deviations are due mainly to the variability of the concentrations in the samples deposited over the stated time interval rather than analytical precision. Observed concentrations of sodium, potassium, magnesium, calcium, silicon and aluminum can be adequately explained by relative abundances of these elements in seawater andterrestrial dust. Late 19th century annual ice layers contain twice as much sulfate as pre-1840 deposits, reflecting the increased use of fossil fuels in the Northern Hemisphere. Lead concentrations in post-1955 snow deposits are more than an order of magnitude greater than pre-1840 baseline concentrations and are attributed to smelting and the increased use of lead alkyls in gasoline.

Beschreibung / Inhaltsverzeichnis: CONTENTS: Abstract. - Preface. - Introduction. - Experimental. - Results and discussion. - Applications. - Literature cited.

Beschreibung / Inhaltsverzeichnis: Chemical analysis of century-old ice from continuous 5 to 7 year intervals of three ice cores from south and central Greenland (Dye 3, Milcent and Crete) show maximum concentrations of Na, Mg,Ca, K, and Al during early spring and minimum concentrations during late summer and early fall. Peak spring values are as much as 10 times greater than fall values. Because of the large seasonal chemical variations, samples used for depth-age or annual deposition rate studies must represent accumulation from exactly one year or whole multiples of a year. The seasonal chemical variations seem promising as a new method of defining annual layers and thus dating old ice cores.

Beschreibung / Inhaltsverzeichnis: CONTENTS: Abstract. - Preface. - Nomenclature. - Introduction. - Description of study. - Sample preparation. - Test equipment and procedure. - Discussion of results. - Stress-density relationship. - Effect of rate of deformation. - Effect of temperature. - Effect of initial snow density. - Stress-deformation relationship. - Summary and conclusions. - Microstructural analysis. - Introduction. - Analytical methods. - Results and discussion. - Conclusion. - Literature cited. - Anpendix: Test data.

Beschreibung / Inhaltsverzeichnis: The effects of snow temperature, rate of deformation, and initial density on the stress vs density and stress vs deformation relationships were investigated in the pressure range of 0.1 to 75 bars. The rate of deformation in the range of 0.027 to 27 cm sec^-1 does not have a significant effect. A decrease in temperature in the range of 0° to -40°C increases the resistance to stress and deformation, the temperature effect increasing with applied pressure and initial density. The effect of initial density is significant. For any stress, an increase in the initial density results in an increase in the resulting density, particularly at low stress levels and at temperatures near 0°C. The texture of artificially compacted snow is significantly different from that of naturally compacted snow of the same density because of the very short recrystallization time period.

Beschreibung / Inhaltsverzeichnis: CONTENTS: Abstract. - Preface. - List of symbols and associated dimensions. - Introduction and purpose. - Site characteristics. - Outline of study scheme. - Analysis. - Heat conduction to the drill hole. - Heat transfer between conduit wall and coolant. - Heat transfer between surface pipe and air. - Total heat extraction process. - Example calculations. - Estimate of basal water thickness and flow rates. - Summary of investigations of multiple-hole. - Literature cited.

Beschreibung / Inhaltsverzeichnis: A scheme for cooling the lower portion of the edge of the Greenland ice sheet, which abuts a potential mining operation, is examined. The magnitude of cooling which may be accomplished by drilling a series of holes about the periphery of the mine site is determined as a function of hole size, spacing and time. Refrigeration is accomplished by pumping a coolant downhole in a central pipe, then uphole in an annulus between the pipe and hole wall, and then through a thin-walled pipe exposed to the surface climate above the ice sheet. It was found possible to achieve a temperature change in the ice of the order of -1°C with hole spacings and pumping requirements which are considered reasonable. Other effects are briefly examined and include an estimate of the basal water thickness and flow rates.

Beschreibung / Inhaltsverzeichnis: CONTENTS: Abstract. - Preface. - USA CRREL project and personnel involvement. - Part I. Introduction. - Background. - Literature review. - Part II. CRREL investigations from 1970 - 1974. - Initial literature survey (1970). - Oil detection kit development. - Survey of Cape Simpson, Alaska, natural crude oil seepages (1970). - Haines-Fairbanks military pipeline investigations (1971-1973). - Barrow investigations (1970-1974). - Fairbanks and Fox investigations. - Germination studies. - Physiological studies. - Dispersant studies. - Microbiological investigations. - Field investigations of accidental petroleum losses. - Part III. Recent related literature. - Part IV. Conclusions and recommendations. - USA CRREL reports, publications and presentations on Alaska oil spill research. - Literature cited.

Beschreibung / Inhaltsverzeichnis: Knowledge concerning the biological effects of oil pollution on arctic and subarctic terrestrial ecosystems is limited. USA CRREL research personnel conducted investigations from 1970 through 1974 to expand information in this field. Objectives were to: 1) define the ecosystems most sensitive to the presence of crude oil or its refined products, 2) quantify and understand the injury response, and 3) establish time frames for manifestation of damage and natural restorative processes in arctic and subarctic regions. This was accomplished through: 1) surveys of natural oil seepages and past accidential spills in the Arctic and Subarctic, 2) initiation of controlled oil spills and 3) detailed laboratory investigations. Results demonstrated that terrestrial oil spills will to some degree be detrimental to both arctic and subarctic plant communities. Degree and longevity of damage will be influenced primarily by the magnitude of the spill, season of occurrence and existing soil moisture content. Rapid recovery of plant communities subjected to spills will occur only if root systems remain relatively unaffected. Damage will be more extensive and long-term when root systems are saturated with oil. Effects of damage will be manifested gradually over several seasons being influenced by winter stresses. Variation does exist in plant species susceptibility. Carex aquatilis, a predominant sedge of the arctic, is markedly resistant to crude oil damage. In the taiga Picea mariana is very susceptible. Plant recovery can be enhanced through the application of fertilizer. Fertilization, in addition to its direct effect on plant nutrition, will stimulate microbial decomposition of crude oil.

Beschreibung / Inhaltsverzeichnis: CONTENTS: Abstract. - Preface. - Introduction. - Experimental procedure. - Experimental and theoretical equations. - Results and discussion. - Conclusions. - Literature cited.

Beschreibung / Inhaltsverzeichnis: Simultaneous laser extinction measurements were made in warm fog at wavelengths of 0.6238, 1.15 and 10.6 [Mu]. The warm fog was generated in a 4-m^3 environmental chamber. Particle sampling was carried out simultaneously with the laser measurements using an impactor. Using the same size distribution in each case the theoretical extinction coefficients were calculated and compared with the experimental coefficients. Results obtained during this experiment and aprevious one indicate that propagation at 1.15 [Mu] is adversely affected by the presence of atmospheric water vapor. Experimental data obtained simultaneously at 0.6328 and 10.6 [Mu] indicate that virtually no difference exists between the extinction coefficients at these two wavelengths for moderate particle concentrations while at much larger concentrations [Alpha]0.6328 increases indefinitely while [Alpha]10.6 levels off at 0.2.

Beschreibung / Inhaltsverzeichnis: CONTENTS: Abstract. - Preface. - Introduction. - Experimental procedure. - Results. - Work-hardening effect. - Strain rate sensitivity of flow stress. - Discussion. - Conclusions. - Literature cited.

Beschreibung / Inhaltsverzeichnis: Single crystals of high purity ice deformed by uniaxial compression on an Instron machine showed remarkable work-hardening after about 8% strain. By changing the strain rate during compression tests in the plastic region of the stress-strain curve, an apparent activation volume V* and a dislocation mobility exponent m were calculated from the strain rate sensitivity of flow stress. The large work-hardening and the rapid increase in the value of m beyond about 10% strain indicate that the plastic flow in this region is controlled by dislocation intersections and nonconservative motion of jogs.

Beschreibung / Inhaltsverzeichnis: CONTENTS: Preface. - Introduction. - Analogy method. - Method based on the bending theory of elastic plates and the criterion [Sigma]max = [Sigma]f. - Methods based on viscoelastic theories. - Methods based on the yield line theory or limit analysis. - Comparison of analytical and test results. - General remarks. - Effect of bending and shearing forces on deflection of an ice cover. - Determination of Pf(O). - Determination of Pf(t). - Determination of [Sigma]f. - Summary and recommendations. - Literature cited.

Beschreibung / Inhaltsverzeichnis: This report contains a critical survey of the literature on the bearing capacity of floating ice plates. It consists of a discussion of general questions, a critical survey of analytical attempts to determine the bearing capacity of floating ice plates, and a survey of field and laboratory tests on floating ice plates and their relation to the analytical results. The paper concludes with a systematic summary of the results, a discussion of observed shortcomings, and suggestions for needed investigations.

Beschreibung / Inhaltsverzeichnis: From a geological perspective, gas hydrates are an important feature of the shallow geosphere. If current estimates are correct, gas hydrates contain more potential fossil fuel energy than is present in conventional oil, gas and coal deposits, although it is uncertain how much of this can be exploited. They are also geological agents that affect the physical, geophysical and geochemical properties of sediments. Oceanic gas hydrates are increasingly recognized as a major potential ha~rd for the stability of offshore structures in various deep-water hydrocarbon provinces. The possibility also exists that a large release of methane from gas hydrates may have a significant impact on the radiative properties of the atmosphere and thus influence global Climatei past~ present and future, Following an introduction and overviews, this book covers; analysis .and modelling of hydrate formation; exploration strategy and reservoir evaluation; regional case studies; relevance to margin~stability and climate change. Hydrate research informatiloln is presented from the USA, Russia, South Asia and the European Union. The individual papers, drawing on hydrate research: by leading :European and American scentists, are well written, with extensive references and high quality graphs and figures. Thorough index. Recommended as a valuable state,of-the-art reference in natural gas hydrates, marine geology, and the environment for students in all the earth science disciplines.

Beschreibung / Inhaltsverzeichnis: CONTENTS: General Introduction. - Part I. Spatial and temporal variations in sea ice deformatfon. - Introduction. - Approach. - Site location and data collection procedures. - Data analysis. - Strain results. - Comparison of mesoscale deformation with macroscale deformation. - Nature of the ice pack rotation. - Conciusion. - Literature cited. - Part Il. Comparison of mesoscale strain measurements with linear drift theory predictions. - Introduction. - List of symbols. - Linear drift equations. - Ice drift solutions. - Comparison of theory with mesoscale measurements. - A more general linear constitutive law. - Conclusions. - Literature cited. - Appendix Relative magnitudes of differential drift forces. - Abstract.

Beschreibung / Inhaltsverzeichnis: Measurements of mesoscale sea ice deformation over a region approximately 20 km in diameter were made over a five-week period in the spring of 1972 at the main AIDJEX camp in the Beaufort Sea. They have been analyzed to determine nonlinearities in the ice velocity field (due to the discrete small-scale nature of the ice pack), as well as a continuum mode of deformation represented by a least squares strain rate tensor and vorticity. The deformation rate time series between Julian day 88 and 113 exhibited net areal changes as large as 3% and deformation rates up to 0.16% per hour. In the principal axis coordinate system, the strain rate typically exhibited a much larger compression (or extension) along one axis than along the other. Persistent cycles at ~12-hour wavelengths were observed in the divergence rate. A comparison of the average residual error with the average strain rate magnitude indicated that strains measured on a scale of 10 km or greater can serve as a valid measure of the continuum motion of the sea ice. This conclusion is also substantiated by a comparison between the mesoscale deformation, and macroscale deformation measured over a ~100-km-diameter region. Vorticity calculations indicate that at low temporal frequencies ( 〈 0.04 hr^-1 ) the whole mesoscale array rotates essentially as an entity and consequently the low frequency vorticity can accurately be estimated from the rotation of a single floe. (Part I) A comparison of mesoscale strain measurements with the atmospheric pressure field and the wind velocity field indicated that the ice divergence rate and vorticity followed the local pressure and wind divergence with significant correlation. For low atmospheric pressures and converging winds, the divergence rate was negative with the vorticity being counterclockwise. The inverse behavior was observed for high pressures and diverging winds. This behavior agreed with predictions based upon the infinite boundary solution of a linearized drift theory in the absence of gradient current effects and using the constitutive law proposed by Glen for pack ice. The best least squares values of the constitutive law parameters [Eta] and [Zeta] were found to be given by ~10^12 kg sec^-1. Using typical divergence rates, these values yielded compressive stresses of the magnitude of 10^5 N m^-1, which are similar to values suggested by the Parmerter and Coon ridge model. In general, the infinite boundary solution of the linear drift equation indicates that in a low pressure region that is reasonably localized in space, the ice would be expected to converge for high compactness (winter) and diverge for low compactness (summer). Calculations were also carried out using a more general linear viscoelastic constitutive law that includes memory effects and that includes a generalized Hooke's law as well as the Glen law as special cases. A best fit of this more general calculation with strain measurements indicates, overall, a better agreement with viscous behavior than with elastic behavior, with the frequency behavior of the estimated "viscosities" similar to the Glen law behavior at temporal frequencies less than ~0.01 hr^-1 (Part II)

Beschreibung / Inhaltsverzeichnis: Although it has long been recognized that what ultimately drives metamorphism and metamorphic reactions is heat, what was less certain is the distribution of heat within the crust, the type and location of major heat sources and the rates of heat flux through crustal rocks. This book explores the factors that control metamorphism and rates of metamorphic processes.

Beschreibung / Inhaltsverzeichnis: The Mediterranean Region represents a complex mosaic of continental, microcontinental and ophiolitic terranes, whose overall evolution has been controlled by relative movements between the African and Eurasian plates. Deciphering the sequence of tectonic events in this region can be likened to attempting to reconstruct all the pictures in a stack of jigsaw puzzles when 90% of the pieces are missing (and the remaining 10% are no longer in their original shape!). Palaeomagnetic studies have played an important part in unravelling this 3D puzzle. The palaeomagnetic technique provides quantitative constraints on our reconstruction, since it can tell us which way each of the remaining pieces should be oriented (using magnetic declinations), their relative position with respect to the top of each picture (using magnetic inclinations), and in some cases which piece belongs to which picture (using magnetic dating). Perhaps more importantly, palaeomagnetism can also tell us something about the processes that led to the present confusion in our puzzle box. The 33 papers in this volume span the full width of the Mediterranean basin and present results from Permian to Quaternary rocks. Together they provide a snap-shot of the current state of palaeomagnetic research in the Mediterranean region. In addition to tectonic and magnetostratigraphic applications of palaeomagnetism, several contributions describe archaeomagnetic studies in the Mediterranean realm.

Beschreibung / Inhaltsverzeichnis: This report presents experimental results on the conditions of initiation of an ice jam by a simple surface obstruction, on the equilibrium thickness of an ice jam formed by accumulation and submergence of ice floes, and on the compression strength of floating, fragmented ice cover. In the study on ice jam initiation, it was found that the minimum concentration of floes in the opening of the obstruction at which a jam occurs is nearly independent of the ratio of width of constricted passage to channel width, and is proportional to a negative power of the ratio of floe length to width of constricted passage. From energy analysis of floe submergence, a relationship relating the thickness of a jam formed by accumulation and submergence of floes to the approach flow characteristics was derived and found to fit satisfactorily the experimental data. In experiments on compression strength of floating, fragmented ice cover it was found that the compressive strength is inversely proportional to compression velocity and independent of cover length.

Beschreibung / Inhaltsverzeichnis: The report deals with the cutting of rock and similar materials by parallel motion tools. It examines cutting forces and energy requirements, taking into consideration tool geometry, wear, operating conditions, and material properties. After an introductory discussion of terminology, some general principles are outlined, and relevant theoretical ideas on metal cutting and rock cutting are reviewed. The next section, which is the heart of the report, reviews experimental data on the magnitudes and directions of cutting forces. There is a graphical compilation of data, including some from obscure or unpublished sources. The variables covered include chipping depth, rake angle, relief angle, side rake, base angle, tool width, tool compliance, tool speed, tool wear, tool interactions, and material properties. The second major part of the report treats the energetics of cutting. It begins with a short discussion of relevant principles, and continues with a compilation and review of experimental data, covering the same independent variables as the force section. The report ends with a concise summary of general behavior for parallel motion tools.

Beschreibung / Inhaltsverzeichnis: A new freezing mechanism, called segregation freezing, is proposed to explain the generation of the suction force that draws pore water up to the freezing surface of a growing ice lens. The segregation freezing temperature is derived by applying thermodynamics to a soil mechanics concept that distinguishes the effective pressure from the neutral pressure. The frost-heaving pressure is formulated in the solution of the differential equations of the simultaneous flow of heat and water, of which the segregation freezing temperature is one of the boundary conditions.

Beschreibung / Inhaltsverzeichnis: The interaction of a 5.1-GHz transverse electric surface wave with a dielectric slab is experimentally investigated. The wave is initially supported by a dielectric substrate resting upon a metallic ground-plane. A slab, made of the same dielectric material as the substrate and variable in height, is then placed upon the waveguide. The results for a small slab sitting on the substrate showed that the discontinuity was a very inefficient launcher of reflected surface waves. Investigations of these reflections with a trough waveguide showed that, for values of slab height comparable to the exponential decay height of the surface wave, the reflections remain very small. However, as the slab height is increased beyond the decay height, the reflected amplitude approaches the theoretical value for a plane wave reflected from the interface between air and the same dielectric. The results are applicable to surface wave methods of microwave deicing of wings and helicopter rotors.

Beschreibung / Inhaltsverzeichnis: The theory of non-coaxial in-plane plastic deformation of soils that obey the Coulomb yield criterion is presented. The constitutive equations are derived by use of the geometry of the Mohr circle and the theory of characteristic lines. It is found that, for solving a boundary value problem, the non-coaxial angle must be given such values that enable us to accommodate the presupposed type of flow in the given domain satisfying the given boundary conditions. The non-coaxial angle is contained in the constitutive equations as a parameter. Therefore, the plastic material obeying the Coulomb yield criterion is a singular material whose constitutive equations are not constant with material but are variable with flow conditions.

Beschreibung / Inhaltsverzeichnis: The viscoelastic deflection of an infinite floating ice plate subjected to a circular load was solved, assuming the Maxwell-Voigt type four-element model. An effective method of numerical integration of the solution integrals was developed, of which each integrand contains a product of Bessel functions extending to infinity. The theoretical curve was fitted to the field data, but the material constants thus found varied with time and location.

Beschreibung / Inhaltsverzeichnis: Many of the technical questions relating to iceberg transport are given brief, but quantitative, consideration. These include iceberg genesis and properties, the mechanical stability of icebergs at sea, towing forces and tug characteristics, drag coefficients, ablation rates, and handling and processing the iceberg at both the pick-up site and at the final destination. In particular the paper attempts to make technical information on glaciological and ice engineering aspects of the problem more readily available to the interested planner or engineer. Specific conclusions include: (1) No unprotected iceberg, no matter how long or wide, would be likely to survive the ablation caused by a long trip to low latitudes. (2) Icebergs that have a horizontal dimension exceeding 2 km may well be prone to breakup by long wavelength swells. (3) To avoid the dangers associated with an iceberg capsizing, the width of a 200-m thick iceberg should always be more than 300 m. (4) For towing efficiency the length/width ratio of a towed iceberg should be appreciably greater than unity. (5) For a pilot project, the selected iceberg would have to be quite small, if for no other reason than the practical availability of tug power.

Beschreibung / Inhaltsverzeichnis: The stress-density relaionships of snow-water mixtures were investigated and are shown as functions of water content, initial snow density, initial snow-water mixture density and rate of deformation. An increase in water content in snow at a particular density or a decrease in the rate of deformation (or strain rate) decreases the stress, but apparently not the specific energy required to reach a specific mixture density.

Beschreibung / Inhaltsverzeichnis: This book provides a synthesis of Archaean and Proterozoic crustal evolution in the North Atlantic Region. There is particular reference to Proterozoic collisional tectonics. The main topics include: Archaean crustal growth; Proterozoic crustal growth; orogenic processes during the Proterozic; geochronology of Proterozoic tectono-thermal processes; and provenance of Proterozoic sediments.

Beschreibung / Inhaltsverzeichnis: The spectral reflectance of natural snow in the range of 0.20- to about 0.40-micrometers wavelengths was studied in the laboratory using both continuous spectral scanning and fixed bandpass measurements. White barium sulfate pressed powder was used as a standard for comparison. The reflectance of fresh snow was found to be very high (usually nearly 100%) and only weakly wavelength dependent from 0.24 micrometers to the visible range. In the 0.20- to 0.24-micrometers portion of the spectrum, the reflectance was found to be quite erratic. Possible reasons for the irregularities in reflectance measurements are discussed.

Beschreibung / Inhaltsverzeichnis: Cold weather limits the successful application of built-up roofing, but often a roof installation must be completed late in the fall or in the winter. The loose-laid protected membrane roof with a synthetic sheet membrane can be installed in the middle of the winter with complete reliability. A synthetic membrane is traditionally more expensive than built-up roofing (rising crude oil prices, however, have reversed this condition), but it has two special features besides its suitability for winter installation: it can be placed on a damp deck, if necessary, and, being losse-laid, it does not split because of deck movement. This report documents information on the installation of two roofs in Anchorage, Alaska, during January and February 1972, including a discussion of the necessary snow removal from the bare deck and the use of portable shelters for preparing the lap joints between sheets during very cold weather. The winter installation caused no special construction problems and the advantages of the synthetic membrane make it an attractive alternative to built-up roofing. The cost of loose-laid protected membrane roofs in Alaska was, in 1972, nearly $300 per square ($28/sq.m), including insulation. Prices are rising as labor costs rise and as more insulation is specified.

Beschreibung / Inhaltsverzeichnis: 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.

Beschreibung / Inhaltsverzeichnis: A literature search was made for information on the accretion of ice on ocean structures and on methods for control. The bulk of the reports were in Russian, with some additional Japanese, British, American, Canadian, and Icelandic sources. Analysis of icing reports indicated that sea spray is the most important cause of ship icing, with lesser amounts due to freezing rain, snow, and fog. Icing is a potential danger whenever air temperatures are below the freezing point of water and the sea temperature is 6 C or lower. Theoretical work on the ice accretion process is discussed, and a method is suggested, based on Russian experiments, for calculating the sea spray accumulation rate for cylindrical and flat surfaces as a function of water source temperature, air temperature, and wind speed. Other factors that influence icing severity are ship size and configuration, angle between ship course and water heading, and ship speed. Icing in the north temperate latitudes generally occurs in the rear of barometric depressions. Maps showing limits of various degrees of icing severity are included. Atmospheric icing measurements on tall land-based structures are presented, and potential maximum accumulations estimated. Control measures are discussed, though no completely effective method is available. Mechanical (impaction) methods are the most common, but experiments have been conducted on heated, icephobic, and deformable surfaces, and with freezing point depressants. No device for the unequivocal measurement of ice accumulation is available, though some experimental methods are suitable for controlled testing; it is recommended that a device be developed.

Beschreibung / Inhaltsverzeichnis: The repair and maintenance costs of low slope roofs are high and their life expectancy is less than desired. The increasing use of insulation is accompanied by a greater incidence of problems. The experience in cold regions amplifies these experiences. Protected membrane roofs have the prerequisites for better performance and the experience to date is encouraging. The results of performance measurements of three roofs built by the Corps of Engineers verify that the membrane remains at nearly constant temperature, independent of the weather, and that the insulation retains its integrity despite periodic wetting. Moisture absorption is slow and appears to stabilize in time due to the self-drying nature of the roof. Heat losses are increased due to rain, and extra insulation should be added to compensate for these losses. The resistance of protected membrane roofs to fire, traffic, impact, and other adverse forces is superior. So far, the initial cost of protected membrane roofs is at a premium, primarily due to the cost of concrete pavers. The initial cost premium can be justified, however, by the reduced repair and maintenance costs as indicated to date, and by the longer life expectancy of the protected membrane. The high probability of superior performance and cost effectiveness is a compelling reason to incorporate protected membrane roofs increasingly in Government construction.

Beschreibung / Inhaltsverzeichnis: At the height of warm weather in Alaska in 1975, temperature measurements were made to determine the extent of the thermal impact on French Creek due to a condenser cooling water impact from the Eielson AFB Power plant. Water temperature measurements during a two-day period failed to show any significant thermal impact on the water in French Creek. It was concluded that no thermal pollution exists due to this warm water input at the volumes and conditions that presently exist.

Beschreibung / Inhaltsverzeichnis: Several membrane materials used or considered for MESL (membrane-enveloped soil layer) utilization of poor soils in road construction have been tested for cold effect on puncture and stiffness. PE (polyethylene) film was also tested for solvent soak effects. A simple blunt needle apparatus was devised for puncture testing. For plastic films (mainly PE), both puncture resistance and stiffness increase at low temperature (0 F, -18 C). For non-woven, spunbonded fabrics these properties are little affected by cold. For both non-wovens and PE film, puncture and bending strengths increase linearly with weight or thickness. The slope is steeper for the non-wovens, which generally are stronger on a per unit weight basis. PE film soaked in a hydrocarbon solvent swelled approximately 17% and lost about 30-40% its puncture strength. These effects are apparently reversible upon drying. Consideration has been given to sealing and patching requirements and to the drying of sealant liquids when adhering film to film. Also considered have been pos­sible slippage related to the reported low angle of friction of plastic films in soil and the possibility of lamination for improved membrane properties.

Beschreibung / Inhaltsverzeichnis: Microorganisms cause mineral precipitation and dissolution and control the distribution of elements in diverse environments at and below the surface of the Earth. Conversely, mineralogical and geochemical factors exert important controls on microbial evolution and the structure of microbial communities. This was the rationale for the Short Course on Geomicrobiology presented by the Mineralogical Society of America on October 18 and 19, 1997, at the Alta Peruvian Lodge in Alta, Utah. Minerals have been known and honored since humans realized their essential contributions to the "terra firma" and stone tools thrust our species on the path of cultural evolution. Microbes are the oldest living creatures, probably inhabiting at least a few salubrious environments on the earth as early as 3.8 billion years ago. At this moment in history we are only beginning to appreciate the intimate juxtaposition and interdependence of minerals and microbes. We have been nudged into this position by the realization that our earth is finite, and the recognition of many global environmental problems that minerals and microbes contribute to, both positively and negatively. In addition, our globe may not be the only site in the solar system where 'life' arose, or may persist. What all of these concerns enunciate is that we as scientists only dimly comprehend our own dynamic "terrestrial halls." This short course and volume have been generated with great enthusiasm for grasping as much as possible of the whole panorama of possibilities that involve both the inorganic and biologic realms . Over 3600 mineral species have been defined and their relationships to each other and the environments in which they form have been documented. This vast data base, collected over the past several hundred years and constantly added to and upgraded, is a monument to the research efforts of many geoscientists focused on the inorganic realm. Much of this data has come from investigators intrigued by the novelty, beauty, and versatility of minerals, direct expressions of the chemistry and physics of geologic processes. We are now adding a new dimension to questions of mineral formation, dissolution, and distribution: what were, are, and will be the contributions of microbes to these basic components of the environment. Microbes have also been known for hundreds of years. However, their small size (0.5 to 5 µm in diameter) and the difficulties associated with identifying a species unless it was grown in the laboratory (cultured), precluded thorough analysis. The advent of molecular biology has only recently made it possible to evaluate microbial evolutionary relatedness (phylogeny) and physiological diversity. These techniques are now being applied to study of microbial populations in natural environments. It is becoming very clear that the surface of Earth is populated by far more species of microbes than there are types of minerals. We are now exploring every portion of the globe and finding the relationships under the rubric "geomicrobiology." The ocean deeps are characterized by a diversity of microorganisms, including those associated with manganese nodules. The profusion and concentration of minerals created at ocean ridges and vents matches the variety of microorganisms, large animals, and plants there. The snowy tops of mountain ranges and glaciers of Antarctica harbor not just ice but whole bacterial communities whose cellular types and activities need elucidation. The equatorial jungles and the deserts, with their enormous diversity of ecological niches, further challenge us. The diversity of geographic, geologic, and biologic environments, including some contributed by humans (e.g. mines, air-conditioning equipment), can now also be explored in detail. Modern studies use protocols developed to preserve or measure in situ chemical and physical characteristics. Electron microscopes allow direct characterization of mineral and biological morphology and internal structures. Spectroscopic techniques permit complimentary chemical analysis, including determination of oxidation states, with very high spatial resolution. Other studies quantitatively measure isotopic abudances. These data serve to distinguish biologically mediated, or biologically controlled formation of the mineral from an abiotic process and mechanism. Each ecological niche requires accurate characterization of the mineralogic and biologic entities in order for us to begin to understand the range of dynamic relationships. We can pose many questions. Is the mineral only a substrate, or is its occurrence and stability impacted by microbiologic activity and metabolic requirements? Which minerals are of microbiological rather than inorganic origin and what are the mechanisms by which organisms dictate the morphology and structure of the solid phase formed? How do organic metabolic products bind metals and change their form and distribution, with implications for metal toxicity and geochemical cycles? How do inorganic reactions such as mineral dissolution and precipitation impact microbial populations through control of their physical and chemical environments? Clearly, new and excitingly research areas exist for all varieties of scientists. Although published by the Mineralogical Society of America, the authors of this volume include microbiologists, molecular biologists, biochemists, biophysicists, bioengineers as well as biomineralogists. Here, they bring together their respective expertise and perspectives to provide disciplinary and interdisciplinary background needed to define and further explore the topic of geomicrobiology. The volume is organized so as to first introduce the nature, diversity, and metabolic impact of microorganisms and the types of solid phases they interact with. This is followed by a discussion of processes that occur at cell surfaces, interfaces between microbes and minerals, and within cells, and the resulting mineral precipitation, dissolution, and changes in aqueous geochemistry. The volume concludes with a discussion of the carbon cycle over geologic time. In detail: Nealson and Stahl acquaint us with the basic properties of prokaryotes, including their size and structure. They define the types and ranges of microorganisms and their metabolisms and describe their impacts on some important biogeochemical cycles. Barns and Nierzwicki-Bauer document the phylogenetic relationships and evolution of microorganisms, begging some fundamental questions that might be now just beyond our grasp: What was the 'last common ancestor'? The physiology, biochemistry and ecology of hyperthermophilic, and the many diverse geologically important microbial species from the lithosphere and hydrosphere, as well as some of the techniques employed, are presented. Banfield and Hamers describe and integrate the processes acting on minerals and at surfaces relevant to microorganisms, examining the factors that control mineralogy, mineral forms, and the stability of phases. Surface properties and reaction rates for dissolution, precipitation, and growth of important classes of minerals are discussed. The possible role of mineral surfaces in formation of prebiotic molecules needed to explain the origin of life is examined. Little, Wagner and Lewandowski describe biofilms, an essential interface between microbes and minerals. They demonstrate that these membranes, with their unique morphological and structural attributes, are sites where much activity related to dissolution and/or formation of minerals takes place. Biology makes it possible to move molecules and elements against a gradient. Many questions regarding the transfer of elements from minerals to microbes at this important heterogeneous interface remain. Fortin, Ferris and Beveridge review surface-mediated mineral development by bacteria. Fresh or oceanic waters, anaerobic or aerobic environments provide discretely different ecologies, bacterial entities, and resulting mineralogies. It is obvious from this presentation that investigators have just scratched the surface of microbial mineralization processes. Bazlinski and Moskowitz review the magnetic biominerals and provide insights into the environmental and biological significance of these few tens of nanometer-sized mineral products. The magnetosome chemistry and biochemistry is probably the best understood of any biologically precipitated mineral. Their formation and unique properties underscore the roles these biomaterials play in the rock magnetic record and in geochemical cycles. Tebo, Ghiorse, van Waasbergen, Siering and Caspi contribute data on the roles of Mnminerals and Mn(II) oxidation in geologic environments. Their chapter encompasses molecular genetic and biochemical investigations. Manganese oxides and oxyhydroxides are notoriously difficult to identify and the crystal chemistry of these phases is a research effort on its own. The prospect of learning how microbes utilize the multiple oxidation states of Mn (2+, 3+ and 4+) as a source of energy sharpens the motivation for interdisciplinary study. Manganese is also known as a cofactor in the production and activation of the enzymes that digest large biomolecules that must be the source of the smaller molecular species and ultimately the building blocks of C, N, 0, H required by all species. How have the mechanisms identified in the bacterial systems been transferred up the phylogenetic tree to plants and humans? This is an expanding and intriguing area for further investigation. DeVrind-de Jong and de Vrind address silicate and carbonate deposition by algae (eukaryotic photosynthetic microorganisms). This chapter documents the mechanisms of biomineralization of diatoms and coccoliths. These abundant aquatic organisms are responsible for huge volumes of siliceous sediments and calcium carbonate deposits world wide. The implications of algal biomineralization for climatic variation throughout much of the Earth's history may be quite significant. Stone leads us though a quantitative approach to evaluating reactions between organic molecules and cations. He considers available extracellular organic ligands and the roles these play in uptake of metals. He documents the basic chemical speciation and complexation for several elements, making metal to metal comparisons. Remaining challenges involve coordinating the organic and inorganic results of biologic activity. Following the discussion of biomineralization and interactions between organic compounds and cations, Silver discusses the strategies microorganisms have evolved to deal with toxic metal concentrations in solution. Beyond the fundamental biological significance, this has important implications for understanding microbial populations in contaminated environments. The impact on the geochemical form (speciation) and distribution of elements is also discussed. Nordstrom and Southam summarize sulfide mineral oxidation and dissolution kinetics and devote considerable effort to describing the specific contributions of microorganisms, mostly bacteria. Despite the vast amount of accumulated information, many unanswered questions remain. Barker, Welch and Banfield address weathering of silicate minerals. This topic encompasses not only mineralogy but geomorphology, microbiology, and geochemistry. The necessary interdisciplinary mode of these investigations is highlighted by discussion of the role(s) of bacterial nutrition, groundwater chemistry, and biochemistry. There are obvious implications for hazardous waste storage, a currently daunting and politicized topic that requires predictions over thousands to millions of years. Finally, Des Marais treats the long term evolution of the carbon cycle, adopting a biogeochemical view. He discusses the sources, sinks and the transfer of the element over geologic time. Consideration of such a basic series of questions relating to the partitioning of carbon necessitate interdisciplinary crossovers. It is a fitting conclusion to a dialogue in progress.