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Heat Extraction from a Hydraulically Fractured Penny-Shaped Crack in Hot Dry Rock

Description: Heat extraction from a penny-shaped crack having both inlet and outlet holes is investigated analytically by considering the hydraulic and thermal growth of the crack when fluid is injected at a constant flow rate. The rock mass is assumed to be infinitely extended, homogeneous, and isotropic. The equations for fluid flow are derived and solved to determine the flow pattern in the crack. Temperature distributions in both rock and fluid are also determined. The crack width change due to thermal contraction and the corresponding flow rate increase are discussed. Some numerical calculations of outlet temperature, thermal power extraction, and crack opening displacement due to thermal contraction of rocks are presented for cracks after they attain stationary states for given inlet flow rate and outlet suction pressure. The present paper is a further development of the previous works of Bodvarsson (1969), Gringarten et al. (1975), Lowell (1976), Harlow and Pracht (1972), McFarland (1975), among others, and considers the two-dimensional rather than the one-dimensional crack. Furthermore, the crack radius and width are quantities to be determined rather than given a priori. 11 refs., 1 tab., 5 figs.
Date: December 1, 1976
Creator: Abe, H.; Mura, T. & Keer, L.M.
Partner: UNT Libraries Government Documents Department

Model for the prediction of the pressure-volume relationship of porous rocks

Description: Several models have been suggested to describe the volume behavior of porous materials under hydrostatic loading. The model presented here accounts for variations in both porosity and the amount of fluid contained within that porosity. The model also attempts to predict the one-dimensional strain loading pressure-volume relationship and the stress difference-confining pressure curve. Only the simplest assumptions were used for the development of this model. These assumptions are discussed and the predictions for Mt. Helen tuff are compared to experimental data.
Date: July 20, 1976
Creator: Abey, A. E.
Partner: UNT Libraries Government Documents Department

Heat transfer in tube bundles of heat exchangers with flow baffles induced forced mixing

Description: Thermal analysis of shell-and-tube heat exchangers is being investigated through geometric modeling of the unit configuration in addition to considering the heat transfer processes taking place within the tube bundle. The governing equations that characterize the heat transfer from the shell side fluid to the tube side fluid across the heat transfer tubewalls are indicated. The equations account for the heat transfer due to molecular conduction, turbulent thermal diffusion, and forced fluid mixing among various shell side fluid channels. The analysis, though general in principle, is being applied to the Clinch River Breeder Reactor Plant-Intermediate Heat Exchanger, which utilizes flow baffles appropriately designed for induced forced fluid mixing in the tube bundle. The results of the analysis are presented in terms of the fluid and tube wall temperature distributions of a non-baffled and baffled tube bundle geometry. The former case yields axial flow in the main bundle region while the latter is associated with axial/cross flow in the bundle. The radial components of the axial/cross flow yield the necessary fluid mixing that results in reducing the thermal unbalance among the heat transfer to the allowable limits. The effect of flow maldistribution, present on the tube or shell sides of the heat exchangers, in altering the temperature field of tube bundles is also noted.
Date: January 1, 1976
Creator: AbuRomia, M. M.; Chu, A. W. & Cho, S. M.
Partner: UNT Libraries Government Documents Department

Vapor deposition of large area NpO/sub 2/ and UO/sub 2/ deposits

Description: Deposition of NpO/sub 2/ and UO/sub 2/ thin films over an area of 7.5 to 10 cm diam has become a routine operation in preparation of fission chamber plates. Vacuum evaporation or electroplating has been used for this purpose. The ''paint brush'' technique has been used as well; however, uniformity requirements normally eliminate this procedure. Vapor deposition in vacuum appears to be the most suitable technique for preparing NpO/sub 2/ and UO/sub 2/ deposits of >200 cm/sup 2/. This paper describes the procedures used in preparing uniform large area deposits of NpO/sub 2/ (approximately 300 cm/sup 2/) and UO/sub 2/ (approximately 2000 cm/sup 2/) by vacuum evaporation using electron bombardment heating and several substrate motion and heating methods to achieve uniformity and adhesion.
Date: January 1, 1976
Creator: Adair, H. L.; Gibson, J. R.; Kobisk, E. H. & Dailey, J. M.
Partner: UNT Libraries Government Documents Department

Radiation-enhanced precipitation in a V-10 wt % Ti alloy

Description: A V-10 wt % Ti alloy was irradiated with 2.7 MeV /sup 51/V/sup +/ at 650/sup 0/C to doses of 2 to 60 dpa. No void swelling was observed at any dose. The irradiation resulted in an enhancement of a precipitation process similar to that observed in unirradiated materials. The precipitates in irradiated specimens were found to have the NaCl-type cubic crystal structure with a lattice parameter of TiO. The orientation relationship between the matrix and the precipitates was the same as that observed under thermal equilibrium conditions in unirradiated materials.
Date: January 1, 1976
Creator: Agarwal, S. C. & Taylor, A.
Partner: UNT Libraries Government Documents Department

Effects of interstitial solutes on the microstructures of self-ion irradiated vanadium

Description: Vanadium and vanadium containing 0.1 percent C, 0.4 percent C, 1.0 percent N, and 1.0 percent O were irradiated with 3-MeV /sup 51/V/sup +/ ions in the temperature range 650 to 880/sup 0/C to a dose level of approximately 20 dpa. The results show that nitrogen is most effective in controlling the void swelling. Carbon and oxygen also suppress the swelling considerably when compared with unalloyed vanadium. Except for V-1.0 percent N, all compositions exhibit a fine platelet precipitate with (012) habit at 650/sup 0/C. In the case of vanadium-carbon alloys, this phase persisted even at higher temperatures. Vanadium and V-1.0 percent O showed fine precipitation on dislocations and void surfaces at 880/sup 0/C. V-0.1 percent C exhibited a metastable (013) carbide precipitate at 880/sup 0/C, whereas V-0.4 percent C showed equilibrium V/sub 2/C phase with some (012) precipitates. This (012) precipitation was irradiation induced and was dependent upon the carbon concentration. V-1.0 percent N did not show any evidence of precipitation over the entire temperature range.
Date: January 1, 1976
Creator: Agarwal, S. C.; Potter, D. I. & Taylor, A.
Partner: UNT Libraries Government Documents Department

Critical properties of a simple spin glass model

Description: The Mattis spin glass model is described as following from a particular quenched random solid solution picture, and its zero-field properties are discussed. The random field model is reviewed. The application to the spin glass problem is made and the more general scaling theory presented, and the limitations of the model are discussed. (GHT)
Date: January 1, 1976
Creator: Aharony, A & Imry, Y
Partner: UNT Libraries Government Documents Department

Plasma experiments with 1. 06-. mu. m lasers at the Lawrence Livermore Laboratory

Description: Recent laser fusion experiments at the Lawrence Livermore Laboratory have provided basic data concerning: laser beam propagation and absorption in high temperature plasmas, electron energy transport processes that transfer the absorbed laser energy to the high-density ablation region, the general fluid dynamic expansion and compression of the heated plasma, and the processes responsible for the production of 14-MeV neutrons during implosion experiments. Irradiation experiments were performed with Nd:YAG glass laser systems: the two-beam Janus (less than or equal to40 J/100 ps, approx.0.4 TW) and Argus (less than or equal to140 J, 35 ps, approx.4 TW), and the single beam Cyclops (less than or equal to70 J/100 ps, approx.0.7 TW). Two classes of targets have been used: glass microshells (approx.40 to 120 ..mu..m in diameter with approx.0.75-..mu..m-thick walls) filled with an equimolar deuterium-tritium mixture, and disks (approx.160 to 600 ..mu..m in diameter and approx. 10 ..mu..m thick) of several compositions. The targets were supported in vacuum (pressure less than or equal to10/sup -5/ Torr) by thin glass stalks. This paper reports on results related to the propagation, absorption, and scattering of laser light by both spherical and planar targets.
Date: December 20, 1976
Creator: Ahlstrom, H. G.; Holzrichter, J. F.; Manes, K. R.; Storm, E. K.; Boyle, M. J.; Brooks, K. M. et al.
Partner: UNT Libraries Government Documents Department

Plasma experiments with 1. 06. mu. m lasers at the Lawrence Livermore Laboratory

Description: Irradiation experiments were performed with the two beam Nd:YAG glass laser systems, Janus(approximately less than 40 J/100 psec, approximately 0.4 TW), Cyclops (approximately less than 70 J/100 psec, approximately 0.7 TW), and Argus (approximately less than 70 J, 35 psec, approximately 2 TW). Two classes of targets have been used, glass microshells (approximately 40 to 120 ..mu..m diameter x approximately 0.75 ..mu..m wall thickness) filled with an equimolar DT mixture and disks (approximately 160 to 600 ..mu..m diameter x approximately 10 ..mu..m thick) of several compositions. The targets were supported in vacuum (pressure approximately less than 10/sup -5/ Torr) by thin glass stalks. This paper reports results related to the propagation, absorption and scattering of laser light by both spherical and planar targets. The absorption measurements cannot be explained using only inverse Bremsstrahlung. The scattered light and the plasma energy are polarization dependent, which is evidence of resonance absorption. The x-ray spectra are characterized by a thermal and a suprathermal distribution. The ''temperature'' of the hot x-rays is given by theta/sub H/ approximately equals I./sup 3/-./sup 4/ depending on the target material. Evidence is also presented which indicates that the laser radiation pressure is producing density steepening in the region of the critical density with n/sub cr/(delta n/delta x)/sup -1//sub cr/ approximately sigma(1 ..mu..m) and in some cases plasma filamentation is observed.
Date: September 19, 1976
Creator: Ahlstrom, H. G.; Holzrichter, J. F.; Manes, K. R.; Storm, E. K.; Haas, R. A.; Phillion, D. W. et al.
Partner: UNT Libraries Government Documents Department

Transport modeling in the environment using the discrete-parcel-random-walk approach

Description: When formulating a mathematical model for simulating transport processes in the environment, the system of interest can be viewed as a continuum of matter and energy or as a large set of small discrete parcels of mass and energy. The latter approach is used in the formulation of the Discrete-Parcel-Random-Walk (DPRW) Transport Model. Each parcel has associated with it a set of spatial coordinates as well as a set of discrete quantities of mass and energy. A parcel's movement is assumed to be independent of any other parcel in the system. A Lagrangian scheme is used for computing the parcel advection and a Markov random walk concept is used for simulating the parcel diffusion and dispersion. The DPRW technique is not subject to numerical dispersion and it can be applied to three-dimensional cases with only a linear increase in computation time. A wide variety of complex source/sink terms can be included in the model with relative ease. Examples of the model's application in the areas of oil spill drift forecasting, coastal power plant effluent analysis, and solute transport in groundwater systems are presented.
Date: April 1, 1976
Creator: Ahlstrom, S. W. & Foote, H. P.
Partner: UNT Libraries Government Documents Department

Position readout by charge division in large two-dimensional detectors. [Linear resistive electrodes]

Description: The improvement in readout spatial resolution for charge division systems with subdivided readout electrodes has been analyzed. This readout forms the position and sum signals by a linear, unambiguous analogue summation technique. It is shown that the readout resolution is a function of only electrode capacitance and shaping parameters. The line width improves as 1/N/sup /sup 1///sub 2//, where N is the number of electrode subdivisions.
Date: October 1, 1976
Creator: Alberi, J L
Partner: UNT Libraries Government Documents Department

Diffusion synthetic acceleration methods for the diamond-differenced discrete-ordinates equations

Description: A class of acceleration schemes is investigated which resembles the conventional synthetic method in that they utilize the diffusion operator in the transport iteration schemes. The accelerated iteration involves alternate diffusion and transport solutions where coupling between the equations is achieved by using a correction term applied to either the diffusion coefficient, the removal cross section, or the source of the diffusion equation. The methods involving the modification of the diffusion coefficient and of the removal term yield nonlinear acceleration schemes and are used in k/sub eff/ calculations, while the source term modification approach is linear at least before discretization, and is used for inhomogeneous source problems. A careful analysis shows that there is a preferred differencing method which eliminates the previously observed instability of the conventional synthetic method. Use of this preferred difference scheme results in an acceleration method which is at the same time stable and efficient. This preferred difference approach renders the source correction scheme, which is linear in its continuous form, nonlinear in its differenced form. An additional feature of these approaches is that they may be used as schemes for obtaining improved diffusion solutions for approximately twice the cost of a diffusion calculation. Numerical experimentation on a wide range of problems in one and two dimensions indicates that improvement from a factor of two to ten over rebalance or Chebyshev acceleration is obtained. The improvement is most pronounced in problems with large regions of scattering material where the unaccelerated transport solutions converge very slowly.
Date: January 1, 1976
Creator: Alcouffe, R. E.
Partner: UNT Libraries Government Documents Department

Magnetic properties of actinide Laves phases

Description: This paper reviews recent high-field (up to 80 kOe) magnetization, nuclear-gamma-ray resonance, and neutron diffraction measurements on a number of actinide ferromagnets with the C-15 Laves phase crystal structure. NpAl/sub 2/ and NpOs/sub 2/ are an interesting contrast; NpAl/sub 2/ behaves as a localized 5f system whereas NpOs/sub 2/ exhibits properties usually associated with itinerant ferromagnets. The second part of the paper reports similar measurements on the series AnFe/sub 2/, where An = U, Np, Pu, and Am. The properties of these compounds suggest an increasing localization of 5f electrons as one proceeds from uranium to americium. The Pu ion in PuFe/sub 2/ is definitely trivalent 5f/sup 5/, but the observation of a small negative moment on the Am site in AmFe/sub 2/ implies a partial occupancy of the Am/sup 2 +/ 5f/sup 7/ state in this compound. This is the first indication of a mixed valence configuration in an actinide system.
Date: January 1, 1976
Creator: Aldred, A. T.; Dunlap, B. D. & Lander, G. H.
Partner: UNT Libraries Government Documents Department

Plasma experiments with 1. 06. mu. m lasers at Lawrence Livermore Laboratory

Description: Recent laser fusion experiments at Lawrence Livermore Laboratory have provided basic data concerning laser beam propagation and absorption in high temperature plasmas, electron energy transport processes that transfer the absorbed laser energy to the high density ablation region, the general fluid dynamic expansion and compression of the heated plasma, and the processes responsible for the production of 14 MeV neutrons during implosion experiments. This paper reports results related to the propagation, absorption and scattering of laser light by spherical and planar targets.
Date: March 12, 1976
Creator: Alhlstrom, H. G.; Holzrichter, J. F.; Haas, R. A.; Storm, E. K.; Manes, K. R.; Phillion, D. W. et al.
Partner: UNT Libraries Government Documents Department

Ammonia as an intermediate heat exchange fluid for dry cooled towers

Description: The feasibility of using ammonia as an intermediate heat exchange fluid, i.e. between the power plant and the dry cooling tower was studied. Information is included on the advantages and disadvantages of using ammonia, design criteria for such a dry cooling system, and a comparative cost projection for the components and overall system. The results showed that the ammonia heat exchange system could save half the cost of transporting the coolant as compared with a conventional indirect cooled dry system, that the heat exchanger cost would be 20 percent less, and the tower would be smaller and cheaper. The condenser/reboiler would be more expensive. Overall a 25 percent saving in total system capital cost and $500 K/yr. in operating costs are projected as compared with wet/dry deluge system of identical capability. Also there are no freezing problems with the ammonia system. It is recommended that: a demonstration unit be designed; performance testing on components be undertaken; a design optimization code for dry/wet systems be developed; and that a test loop be constructed and operated. (LCL)
Date: September 1976
Creator: Allemann, R T; Johnson, B M & Smith, G C
Partner: UNT Libraries Government Documents Department

The development of liquid-fluidized bed heat exchangers for controlliing the deposition of scale in geothermal applications

Description: Geothermal energy development has been slowed by the problem of scale formation on heat transfer surfaces. This is the case either in converting to electrical energy by using a secondary cycle, or in transferring heat for industrial processes. The object of the program is to develop an economically competitive heat exchanger in which scale formation on heat transfer surfaces is controlled. Experiments conducted several years ago at the Idaho National Engineering Laboratory indicated that heat transfer coefficients between surfaces and a liquid fluidized bed were higher than when no bed was present. These same beds prevented deposition on cold surfaces near saturated solutions. These observations led to the suggestion that a fluidized bed heat exchanger could be developed which would prevent the usual deposition of scale from geothermal brines when cooled.
Date: January 1, 1976
Creator: Allen, C.A.; Grimmett, E.S. & McAtee, R..
Partner: UNT Libraries Government Documents Department

Development of lightweight compound parabolic concentrators for solar thermal electric and process heat applications

Description: The design and construction of a lightweight collector panel that uses the Compound Parabolic Concentrator (CPC) to achieve maximal concentration with minimal tracking requirements is described. The primary goal of the effort has been the development of methods of constructing the units with low cost materials that still allow high temperature (120 to 230/sup 0/C) operation. The use of thermoformed plastics for both the container box and the reflector substrate has been investigated for use in combination with an evacuated glass tube around the absorber plate. The predicted performance of the collector has been calculated, and the problem of keeping the reflectors cool has been addressed. Preliminary results on the reflector tests are presented.
Date: January 1, 1976
Creator: Allen, J.; Levitz, N.; Rabl, A.; Reed, K.; Schertz, W. & Winston, R.
Partner: UNT Libraries Government Documents Department

Large-scale digitizer system (LSD) for charge and time digitization in high-energy physics experiments

Description: A large-scale digitizer (LSD) system for acquiring charge and time-of-arrival particle data from high-energy-physics experiments has been developed at the Lawrence Berkeley Laboratory. The objective in this development was to significantly reduce the cost of instrumenting large-detector arrays which, for the 4..pi..-geometry of colliding-beam experiments, are proposed with an order of magnitude increase in channel count over previous detectors. In order to achieve the desired economy (approximately $65 per channel), a system was designed in which a number of control signals for conversion, for digitization, and for readout are shared in common by all the channels in each 128-channel bin. The overall-system concept and the distribution of control signals that are critical to the 10-bit charge resolution and to the 12-bit time resolution are described. Also described is the bit-serial transfer scheme, chosen for its low component and cabling costs.
Date: October 1, 1976
Creator: Althaus, R. F.; Kirsten, F. A.; Lee, K. L.; Olson, S. R.; Wagner, L. J. & Wolverton, J. M.
Partner: UNT Libraries Government Documents Department

Large-scale digitizer system, analog converters. [For use with drift chambers or scintillator-photodiode detectors]

Description: Analog to digital converter circuits that are based on the sharing of common resources, including those which are critical to the linearity and stability of the individual channels, are described. Simplicity of circuit composition is valued over other more costly approaches. These are intended to be applied in a large-scale processing and digitizing system for use with high-energy physics detectors such as drift-chambers or phototube-scintillator arrays. Signal distribution techniques are of paramount importance in maintaining adequate signal-to-noise ratio. Noise in both amplitude and time-jitter senses is held sufficiently low so that conversions with 10-bit charge resolution and 12-bit time resolution are achieved.
Date: October 1, 1976
Creator: Althaus, R. F.; Lee, K. L.; Kirsten, F. A. & Wagner, L. J.
Partner: UNT Libraries Government Documents Department

Subterrene rock-melting concept applied to the production of deep geothermal wells

Description: The drilling of wells comprises a large fraction of the costs of geothermal energy-extraction plants, and billions of dollars for wells will be needed before geothermal energy is nationally significant. Technical and cost studies were made of the application of the Subterrene concept, i.e., excavating and penetrating rocks or soils by melting, to deep wells such as may be used for dry-hot-rock or geopressure geothermal energy extraction systems. Technically, it was found that Subterrene requirements are compatible with those of current rotary drilling practices. Certain features of the rock-melting concept such as the glass lining on the borehole wall, and nonrotation, provide opportunities for the development of better well production techniques in hot wells. A typical optimum-cost well would be rotary-drilled in the upper regions and then rock-melted to total depth. Indicated cost-savings are significant: a 33 percent or 4.5 million dollars reduction from rotary drilled well costs are estimated for a 10 km depth well with bottom hole temperatures of 673 K. Even for normal geothermal gradient conditions, the savings for the 10 km depth is estimated as 23 percent or 2 million dollars.
Date: January 1, 1976
Creator: Altseimer, John H.
Partner: UNT Libraries Government Documents Department

Ignition inhibitors for cellulosic materials. [Fire retardants; effects of irradiation]

Description: By exposing samples to various irradiance levels from a calibrated thermal radiation source, the ignition responses of blackened alpha-cellulose and cotton cloth with and without fire-retardant additives were compared. Samples treated with retardant compounds which showed the most promise were then isothermally pyrolyzed in air for comparisons between the pyrolysis rates. Alpha-cellulose samples containing a mixture of boric acid, borax, and ammonium di-hydrogen phosphate could not be ignited by irradiances up to 4.0 cal cm/sup -2/ s-1 (16.7 W/cm/sup 2/). At higher irradiances the specimens ignited, but flaming lasted only until the flammable gases were depleted. Cotton cloth containing a polymeric retardant with the designation THPC + MM was found to be ignition-resistant to all irradiances below 7.0 cal cm/sup -2/ s/sup -1/ (29.3 W/cm/sup 2/). Comparison of the pyrolysis rates of the retardant-treated alpha-cellulose and the retardant-treated cotton showed that the retardant mechanism is qualitatively the same. Similar ignition-response measurements were also made with specimens exposed to ionizing radiation. It was observed that gamma radiation results in ignition retardance of cellulose, while irradiation by neutrons does not.
Date: April 5, 1976
Creator: Alvares, N. J.
Partner: UNT Libraries Government Documents Department

Impact of Energy Production on Human Health: An Evaluation for Means for Assessment

Description: The symposium explored the various techniques and methods available to study the potential effects that various energy-producing industries may have on human health. Three papers presented at Session I dealt with national energy needs, resources, and future developments; responsibilities and capabilities in ERDA as related to the health and environmental impacts of energy productions; and health hazards associated with alternate energy sources. Four papers presented at Session II reviewed standards setting for the worker and for the public; the radiation experience; and developing health policies and standards as the responsibility of the scientist. Eight papers in Sessions III and IV, Sources of Information, dealt with developing a health standard from epidemiological and clinical data and from laboratory animal data; carcinogenesis, mutagenesis, teratogenesis, and behavior changes as end points in health impact assessments; new methods and approaches to health impact assessment; problems in sampling for health impact; and the application of scientific data to worker/workplace health decision making. Two papers at Session V covered bases for the application of scientific data to health standards and health and environmental standards from a legal viewpoint. A final discussion, Room for Controversy, was conducted by four panelists. (MCW)
Date: January 1, 1976
Creator: Anderson, Ernest C. & Sullivan, Elizabeth M.
Partner: UNT Libraries Government Documents Department