ALBERT

Description / Table of Contents: Geochemistry is a science that is based on an understanding of chemical processes in the earth. One of the principal tools available to the chemist for understanding systems at equilibrium is thermodynamics. The awareness and application of thermodynamic techniques has increased at a very fast pace in geosciences; in fact, one may be so bold as to say that thermodynamics in geology has reached the "mature" stage, although much future thermodynamic research is certainly needed. However, the natural processes in the earth are often sluggish enough that a particular system may not reach equilibrium. This observation is being supported constantly by new experimental and field data available to the geochemist e.g. the non-applicability of the phase rule in some assemblages, the compositional inhomogeneities of mineral grains, the partial reaction rims surrounding original minerals, the lack of isotopic equilibration or the absence of minerals (e.g. dolomite), which should be present according to thermodynamics. The need to apply kinetics has produced a large number of papers dealing with kinetics in geochemistry. As an initial response to this growing field, a conference on geochemical transport and kinetics was conducted at Airlie House, VA, in 1973, sponsored by the Carnegie Institution of Washington. The papers there dealt with several kinetic topics including diffusion, exsolution, metasomatism and metamorphic layering. Since 1973 the number of kinetic papers has continued to increase greatly. Therefore, the time is ripe for a Short Course in Kinetics, which brings together the fundamentals needed to explain field observations using kinetic data. It is hoped that this book may serve, not only as a reference for researchers dealing with the rates of geochemical processes, but also as a text in courses on geochemical kinetics. One of us has found this need of a text in teaching a graduate course on geochemical kinetics at Harvard and at Penn State during the past several years. Finally, it is our hope that the book may itself further even more research into the rates of geochemical processes and into the quantification of geochemical observations. The book is organized with a rough temperature gradient in mind, i.e. low temperature kinetics at the beginning and igneous kinetics at the end (no prejudices are intended with this scheme!). However, the topics in each chapter are general enough that they can be applied often to any geochemical domain: sedimentary, metamorphic or igneous. The theory of kinetics operates at two complementary levels: the phenomenological and the atomistic. The former relies on macroscopic variables (e.g. temperature or concentrations) to describe the rates of reactions or the rates of transport; the latter relates the rates to the basic forces operating between the particular atomic or molecular species of any system. This book deals with both descriptions of the kinetics of geochemical processes. Chapter one sets the framework for the phenomenological theory of reaction rates. If any geochemical reaction is to be described quantitatively, the rate law must be experimentally obtained in a kinetically sound manner and the reaction mechanism must be understood. This applies to heterogeneous fluid-rock reactions such as those occurring during metamorphism, hydrothermal alteration or weathering as well as to homogeneous reactions. Chapter 2 extends the theory to the global kinetics of geochemical cycles. This enables the kinetic concepts of stability and feedback to be applied to the cycling of elements in the many reservoirs of the earth. Chapter 3 applies the phenomenological treatment of chapter 1 to diagenesis and weathering. The rate of dissolution of minerals as well as the chemical evolution of pore waters are discussed. The atomistic basis of rates of reaction, transition state theory, is introduced in Chapter 4. Transition state theory can be applied to relate the rate constants of geochemical reactions to the atomic processes taking place. This includes not only homogeneous reactions but also reactions that occur at the surface of minerals. Chapter 5 discusses the theory of irreversible thermodynamics and its application to petrology. The use of the second law of thermodynamics along with the expressions for the rate of entropy production in a system have been used successfully since 1935 to describe kinetic phenomena. The chapter applies the concepts to the growth of minerals during metamorphism as well as to the formation of differentiated layers (banding) in petrology. Chapter 6 describes the phenomenological theory of diffusion both in aqueous solutions and in minerals. In particular, the multicomponent nature of diffusion and its consequence in natural systems is elaborated. Chapter 7 provides the atomistic basis for the rates of reactions in minerals. Understanding of the rates of diffusion, conduction, order-disorder reactions or exsolution in minerals depends on proper description of the defects in the various mineral structures. Chapter 8 provides the kinetic theory of crystal nucleation and growth. While many of the concepts in the chapter can be applied to aqueous systems, the emphasis is on igneous processes occurring during crystallization of a melt. To fully understand both the mineral composition as well as the texture of igneous rocks, the processes whereby new crystals form and grow must be quantified by using kinetic theory. Due to space and time limitations (kinetics!) some topics have not been covered in detail. In particular, the mathematical solution of diffusion or conduction equations is discussed very well by Crank in his book, Mathematics of Diffusion, and so is not covered to a great extent here. The treatment of fluid flow (e.g. convection) is also not covered in the text.

Description / Table of Contents: Ice fog suppression experiments on the Fort Wainwright Power Plant cooling pond were conducted during the winters of 1974-76. Baseline information studies occupied a sizable portion of the available ice fog weather in 1974-75. Then hexadecanol was added to the pond and dramatically improved visibility by reducing fog generated from water vapor released by the pond at -14 C. Although this temperature was not low enough to create ice fog, the cold vapor fog created was equally as devastating to visibility in the vicinity of the pond. During the winter of 1975-76, suppression tests were continued using films of hexadecanol, mixes of hexadecanol and octadecanol, and ethylene glycol monobutyl ether (EGME). Suppression effectiveness at colder temperatures was stuided and limits to the techniques were probed. A reinforcing grid was constructed that prevented breakup of the film by wind and water currents. Lifetime tests indicated that EGME degrades much more slowly than either hexadecanol or the hexadecanol-octadecanol mix. The films were found to be very effective fog reducers at warmer temperatures but still allowed 20% to 40% of normal evaporation to occur. The vapor thus produced was sufficient to create some ice fog at lower temperatures, but this ice fog occurred less frequently and was more quickly dispersed than the thick fog that was present before application of the films.

Description / Table of Contents: Nondestructive repetitive plate bearing (RPB) tests were conducted on various test sections in state highways in Maine during 13-15 April 1976. The RPB test consists of making resilient surface deflection measurements during repetitive loadings at various radii from the load plate. The pavement system stiffness was calculated and the resilient modulus values for the various pavement layers were determined with the Chevron computer program for a layered elastic system. A thawed analysis using nondimensional deflection curves for the various sections provided a guide to the susceptibility of the pavement systems to surface failure and pothole development. Some comparisons between stabilized and nonstabilized aggregate and soil were made with calculated stiffness values. The moduli of the various materials were also compared. The residual surface deflections during testing for several pavement systems indicated a linear logarithmic relationship with number of load applications. A relationship between the modulus of the asphalt cement concrete pavement and pavement temperature was developed for the limited temperature range during the testing.

Description / Table of Contents: Large, simply supported beams of temperate lake ice were found, generally, to yield significantly higher flexural strengths than the same beams tested in the cantilever mode. Data support the view that a significant stress concentration may exist at the fixed corners of the cantilever beams. Maximum effects are experienced with beams of cold, brittle ice substantially free of structural imperfections; for this kind of ice the strength difference factor, here attributed to the effect of stress concentrations, may exceed 2.0; that is, simply supported beams test a factor of 2 or more stronger than the same beams tested in the cantilever mode. In ice that has undergone extensive thermal degradation, the stress concentration effect may be eliminated entirely. Simply supported beams generally yield higher strengths when the top surfaces are placed in tension. This behavior is attributed to differences in ice type; the fine-grained, crack-free top layer of snow-ice which constituted up to 50% of the ice cover in the current series of tests usually reacted more strongly in tension than the coarse-grained crack-prone bottom lake ice.

Description / Table of Contents: 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.

Description / Table of Contents: 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.

Description / Table of Contents: 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.

Description / Table of Contents: An experimental study of forced convective heat transfer over a vertical melting plate has been conducted. This study covers water velocities ranging from 1.7 to 9.8 mm/s and bulk water temperatures from 1.11 to 7.50 C. The experimental results are correlated in terms of Nusselt, Prandtl and Reynolds numbers with a moderate correlation coefficient of 0.843. The results are expected to be useful in predicting the heat transfer characteristics of a much larger prototype ice-water heat sink.

Description / Table of Contents: Uniaxial compression and tension tests were conducted on polycrystalline snow-ice to determine the effect of temperature on its strength. Test temperatures ranged from -O.1C to -54C. Two machine speeds, 0.847 mm/s and84.7 mm/s were used for the constant displacement rate tests. The compressive strength at -54C was about oneorder of magnitude higher than at -0.1C. The tensile strength at -18C was about 20% higher than at 0.1C. The initial tangent and 50% strength moduli are given for the compression tests, while the secant modulus to failure is given for the tension tests.The mode of fracture is discussed and the test results are compared with data from other investigations.

Description / Table of Contents: Abstract: Measurements of the concentrations of Aitken nuclei in maritime air were made near Barrow, Alaska, in June 1975 with a modified Nolan-Pollack small-particle detector. The concentrations varied from 50 to 300 particles cm^-3 depending upon meteorological conditions. The mean Aitken nuclei count was 100 particles cm^-3 for diameters greater than 2 x 10^-3 μm. Transmission electron micrographs of aerosols in maritime air near Barrow were taken. The size range was measured to be 0.01 to 2.5 μm in diameter with the most frequently observed diameter being 0.04 μm. The volume of the maritime air and the collection efficiency of aerosol particles on filmed grids for electron microscopy were measured. The aerosol concentrations were found to be 76 to 101 particles cm^-3 ; the mean concentration was calculated to be 87 particles cm^-3. The aerosol particles in the maritime air were identified by electron microscopy and selected area electron diffraction analysis. About 20% of the aerosol particles were identified, and 80% of the particles were too small for electron diffraction analysis. Sea salt particles constituted 2% of the total, and clay minerals 3%; these particles were considered to be of natural origin. Solid combustion by-products such as coagulated carbon particles and fly ash particles constituted 16%. Despite the comparative remoteness of the sampling site, the measurements indicate that many anthropogenic aerosols were found using an electron microscope.

Description / Table of Contents: 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.

Description / Table of Contents: The use of radio-echo sounding records to indicate the presence of internal layers within large ice sheets is of interest to glaciologists because it offers a means of tracking the internal properties of the ice sheets over large distances. The interpretation of the reflections obtained in this manner is more valuable, however, if a physical property change relating to the glaciological regime can be related to the dielectric property change producing the radio-echo reflections. In this report, we use the measured physical properties of core to bedrock taken at Cape Folger, East Antarctica (66 deg 22 min s, 111 deg (E), 324-m depth), to compute a profile of dielectric properties and from this, a depth-reflection coefficient profile for comparison with observed radio-echo reflections. The measurements available on physical properties are: density variations, bubble size and shape changes, and crystal fabric variations. The depths of the strong reflections shown on the available radio-echo records are in reasonable agreement with the depths corresponding to the highest reflection coefficients computed from the combined physical property measurements. In calculations to differentiate the separate effects of different physical properties, it appears that density variations account for the primary contributions to the calculated dielectric property changes corresponding to the highest reflection coefficients. However, bubble changes alone can also account for reasonable, though lower, reflection coefficients at the appropriate depths. Crystal fabric variations correspond poorly with the reflection locations. Density variations are normally associated with depositional events in the history of the ice sheet.

Description / Table of Contents: 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.

Description / Table of Contents: Two performance indicators, effectiveness and thermal efficiency, are defined and used to evaluate the year-round performance of three protected membrane roofs in Alaska and New Hampshire. Effectiveness is a measure of the deviations of ceiling temperatures from a yearly average, with large diviations indicating erratic performance in the roofing-insulation system and small departures indicating a thermally stable system. Thermal efficiency, the ratio of calculated heat loss to measured heat loss, is affected by climatic conditions such as rain, snow, solar radiation and wind. Thermal efficiency values of 100% or greater are possible since the calculated heat loss is based only on the inside and outside air temperature differences and the thermal properties of the roof components. Results of the year-round evaluation indicate that the three protected membrane roofs generally have high values of both effectiveness and thermal efficiency.

Description / Table of Contents: A computer program to calculate the increased live load on a snow-covered roof due to rain-on-snow is given. For the 25-year rainstorm falling on a heavy snow load on a flat roof in Hanover, New Hamsphire, and additional 98 kg/m2 (20 lb/ft2) of liquid water is added to the live load. The additional load due to rain-on-snow is very sensitive to the snow properties and characteristics of the roof. A wide range of live loads is possible, depending on the particular circumstances.

Description / Table of Contents: Abstract: The amount of force that an ice sheet can apply to a vertical pile was tested by lowering a hydraulic ram device into a hole cut in an existing ice sheet. The device had a large base and shoved a relatively narrow vertical pile in a horizontal direction. Test variables were: pile widths - 1.5 in. to 36.7 in.; pile shapes - flat, round, 45 ° and 90° wedges; ice thickness - 2.6 in. to 8.8 in.; and ram speed - 0.07 in./sec to 18.75 in./sec; but not all shapes and sizes were tested at all speeds. Air temperature was 20 ° F (-6.7 ° C). Forces and displacements were measured electronically. The findings are presented as a table of test results and as bar graphs of the resultant ice pressures versus the pile width-to-ice-thickness ratio, pile width and shape combination and pile velocity. The types of failures in the ice sheet were classified as crushing, splitting, buckling, bending, and creeping. The ice sheet generally withstood a high initial load followed by several lower peak load levels. The maximum ice pressure measured was 610 psi for a 12.6-in.-diam round pile in 8.4-in.-thick ice.

Description / Table of Contents: The mathematical theory for the bearing capacity of river ice for vehicles is presented. The floating ice sheet is assumed to have simple supports at the shore line. Solutions are presented for loads uniformly distributed over circular and rectangular areas. Numerical evaluations are made for a number of vehicles and the results presented in graphical form

Description / Table of Contents: Results of measurements of salinity, grain size, substructure dimensions and crystal fabrics of the undeformed 2.15-m-thick annual sea ice sheet near Narwhal Island, Alaska, are presented. A notable observation was the formation of a dominant c-axis horizontal structure in all ice below 14 cm, including transformation to a pronounced east-west alignment of the c-axes by a depth of 66 cm. This study confirms earlier reports of the occurrence of very strong horizontal c-axis alignments in arctic fast ice.

Description / Table of Contents: 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.

Description / Table of Contents: A theory for ice forces acting on inclined wedges has been developed, thus making it possible to predict the magnitude of the intermittent ice forces from knowledge of the physical parameters of the system. The theory has been verified by model tests with artificial and natural ice.

Description / Table of Contents: Results of a study to determine the feasibility of using an impulse radar to detect moisture variations in the built-up roof at CRREL and to monitor the curing of concrete are presented. The results indicate that impulse radar can be used to detect wide variations in roof moisture associated with built-up roof surface deterioration and that this technique has the potential of providing a nondestructive test method for measuring the strength of concrete during curing.

Description / Table of Contents: This report, which is one of a series on the mechanics of cutting and boring in rock, deals with the kinematics of machines which utilize a continuous belt as the cutting unit (e.g. coal saws, shale saws, digger-chain trenchers). The discussion and analysis cover the geometry and motion of various components of the cutting system, including such topics as chipping depth, production and conveyance of cuttings, tool trajectories, tool speeds, tool angles, and arrangement of cutting tools on the belt. Worked examples are included to illustrate the application of various equations to practical problems

Description / Table of Contents: Under ordinary conditions the freezing of water begins with supercooling and ice nucleation, and proceeds at 0°C at the ice/water interface until ice formation stops. The presence of solutes, high pressure, or dispersal in fine pores causes the water to freeze at temperatures below 0°C (the so-called freezing point depression). Whenever freezing begins, it pro­ceeds at a constant temperature, or at a temperature which becomes progressively lower. A temperature rise during ice formation is considered here to be an anomaly. Under all equal circumstances, the conditions under which an anomal­ous freezing temperature is observable appear to be very special. This report describes two different experiments dis­playing the anomalous rise of temperature after nucleation and during ice formation. In one case the water was dispersed in the fine pores of fine powders; in the other case pure water was frozen in a transparent insulated cell. Photographic observations were made; relations of ice surface to water volume were measured.

Description / Table of Contents: Three surface elevation and ice thickness profiles obtained during the 1972 Arctic Ice Dynamics Joint Experiment on a multiyear ice floe were analyzed to obtain relationships between surface elevation, thickness and physical properties of the ice. It was found that for ice freeboards from 0.10 m to 1.05 m above sea level a linear relationship between ice density and freeboard could be postulated. The equation for the regression line is: Ice density = -194f' + 974 kg/cu m where f' is the ice freeboard plus snow depth in ice equivalent at the point in question. This statistical relationship is consistent with observed physical properties, which indicate that as the ice freeboard increases, ice salinity decreases and the higher freeboard or thicker ice therefore decreases in density. Using this variable density with freeboard relationship, a model was constructed to predict ice thickness, given ice freeboard and snow depth alone. This prediction is desirable, since snow depth and freeboard are relatively easy to obtain, whereas ice thickness can usually be obtained only by drilling through the ice. The model was compared with two other models. It was found that the variable density prediction model gave the best approximation to observed ice thickness, with a standard error between the measured and predicted value of about 0.4 m, compared with errors from 50 to 100% higher for the other two models.

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.