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Model catalytic oxidation studies using supported monometallic and heterobimetallic oxides

Description: This research program is directed toward a more fundamental understanding of the effects of catalyst composition and structure on the catalytic properties of metal oxides. Metal oxide catalysts play an important role in many reactions bearing on the chemical aspects of energy processes. Metal oxides are the catalysts for water-gas shift reactions, methanol and higher alcohol synthesis, isosynthesis, selective catalytic reduction of nitric oxides, and oxidation of hydrocarbons. A key limitation to developing insight into how oxides function in catalytic reactions is in not having precise information of the surface composition under reaction conditions. To address this problem we have prepared oxide systems that can be used to study cation-cation effects and the role of bridging (-O-) and/or terminal (=O) surface oxygen anion ligands in a systematic fashion. Since many oxide catalyst systems involve mixtures of oxides, we selected a model system that would permit us to examine the role of each cation separately and in pairwise combinations. Organometallic molybdenum and tungsten complexes were proposed for use, to prepare model systems consisting of isolated monomeric cations, isolated monometallic dimers and isolated bimetallic dimers supported on silica and alumina. The monometallic and bimetallic dimers were to be used as models of more complex mixed- oxide catalysts. Our current program was to develop the systems and use them in model oxidation reactions.
Date: February 3, 1992
Creator: Ekerdt, J.G.
Partner: UNT Libraries Government Documents Department

Excitation of solitons by an external resonant wave with a slowly varying phase velocity

Description: A novel mechanism is proposed for the excitation of solitons in nonlinear dispersive media. The mechanism employs an external pumping wave with a varying phase velocity, which provides a continuous resonant excitation of a nonlinear wave in the medium. Two different schemes of a continuous resonant growth (continuous phase-locking) of the induced nonlinear wave are suggested. The first of them requires a definite time dependence of the pumping wave phase velocity and is relatively sensitive to the initial wave phase. The second employs the dynamic autoresonance effect and is insensitive to the exact time dependence of the pumping wave phase velocity. It is demonstrated analytically and numerically, for a particular example of a driven Korteweg-de Vries (KdV) equation with periodic boundary conditions, that as the nonlinear wave grows, it transforms into a soliton, which continues growing and accelerating adiabatically. A fully nonlinear perturbation theory is developed for the driven KdV equation to follow the growing wave into the strongly nonlinear regime and describe the soliton formation.
Date: February 1, 1992
Creator: Aranson, I.; Meerson, B. (Hebrew Univ., Jerusalem (Israel). Racah Inst. of Physics) & Tajima, Toshiki (Texas Univ., Austin, TX (United States))
Partner: UNT Libraries Government Documents Department

Parallel supercomputing: Advanced methods, algorithms and software for large-scale problems

Description: Research has continued with excellent progress and new results on methodology and algorithms. We have also made supporting benchmark application studies on representative parallel computing architectures. Results from these research studies have been reported at scientific meetings, as technical reports and as journal publications. A list of pertinent presentations and publications is attached. The work on parallel element-by-element techniques and domain decomposition schemes has developed well. In particular, we have focused on the use of finite element spectral methods (or high p methods) on distributed massively parallel systems. The approach has been implemented in a prototype finite element program for solution of coupled Navier Stokes flow and transport processes. This class of problems is of fundamental interest and basic to many grand challenge'' type problems for which parallel supercomputing is warranted.
Date: April 1, 1992
Creator: Carey, G.F. & Young, D.M.
Partner: UNT Libraries Government Documents Department

Oil recovery from naturally fractured reservoirs by steam injection methods

Description: The objective of this study is to develop accurate models for predicting oil recovery in naturally fractured reservoirs by steam injection. This objective is being met through an integrated experimental, numerical, and analytical study of the recovery mechanisms that control oil recovery for this process. These mechanisms include capillary imbibition, thermal expansion, gas generation from chemical reactions, and temperature-dependent thermal properties.
Date: January 1, 1991
Creator: Reis, J. & Miller, M.
Partner: UNT Libraries Government Documents Department

Effects of stratal architecture and diagenesis on reservoir development in the Grayburg formation: SSouth Cowden field, Ector County, Texas. Annual report, 1 October 1994--30 September 1995

Description: This report presents the results of geological characterization studies in a typical Grayburg reservior in the Permian Basin. The work applies geological models developed in outcrop studies to better constrain the geological reservoir framework and heterogeneity in a typical Grayburg reservoir, The South Cowden Grayburg reservoir. This framework provides a strong basis for defining petrophysical and flow unit properties in the reservior and serves as a prototype model for other Grayburg reservoir characterization studies. The Grayburg Formation in the South Cowden field of eastern Ector County displays an internal stratal architecture that typifies Grayburg shallow-water platform successions throughout the Permian Basin. Study of core and wireline logs in South Cowden field documents three orders of cyclicity in the Grayburg. The entire Grayburg constitutes a single long-duration accommodation cycle that commenced with a major sea-level rise. Two major diagenetic events strongly affect reservoir character in some parts of the field. Recrystallized dolomite is developed along vertical burrows in highly cyclic mud-dominated packstones and wackestones of the HFS 4 Grayburg highstand succussion. Later alteration and removal of anhydrite are focused in structurally low sections along the eastern and southern margins of the field.
Date: February 1, 1996
Creator: Ruppel, S. & Bebout, D.
Partner: UNT Libraries Government Documents Department

Compact tokamak reactors. Part 1 (analytic results)

Description: We discuss the possible use of tokamaks for thermonuclear power plants, in particular tokamaks with low aspect ratio and copper toroidal field coils. Three approaches are presented. First we review and summarize the existing literature. Second, using simple analytic estimates, the size of the smallest tokamak to produce an ignited plasma is derived. This steady state energy balance analysis is then extended to determine the smallest tokamak power plant, by including the power required to drive the toroidal field, and considering two extremes of plasma current drive efficiency. The analytic results will be augmented by a numerical calculation which permits arbitrary plasma current drive efficiency; the results of which will be presented in Part II. Third, a scaling from any given reference reactor design to a copper toroidal field coil device is discussed. Throughout the paper the importance of various restrictions is emphasized, in particular plasma current drive efficiency, plasma confinement, plasma safety factor, plasma elongation, plasma beta, neutron wall loading, blanket availability and recirculating electric power. We conclude that the latest published reactor studies, which show little advantage in using low aspect ratio unless remarkably high efficiency plasma current drive and low safety factor are combined, can be reproduced with the analytic model.
Date: September 13, 1996
Creator: Wootton, A. J.; Wiley, J. C.; Edmonds, P. H. & Ross, D. W.
Partner: UNT Libraries Government Documents Department

A novel approach to modeling unstable BOR displacements. Annual report, August 1991--September 1992

Description: This research is aimed at developing a methodology for predicting the performance of unstable displacements in heterogeneous reservoirs. A performance prediction approach that combines numerical modeling with laboratory imaging experiments is being developed. Flow visualization experiments are being performed on laboratory corefloods using X-ray computed tomography (CT) and other imaging technologies to map the insitu fluid saturations in time and space. A systematic procedure is being developed to replicate the experimental image data with high-resolution numerical models of the displacements. The wall-tuned numerical models will then be used to scale the results of the laboratory coreflood experiments to heterogeneous reservoirs in order to predict the performance of unstable displacements in such reservoirs. Accomplishments for the year are presented for the following tasks: flow visualization experiments with CT scanner; flow visualization experiments with imaging workstation; model development and testing; and history match of the flow visualization experiments.
Date: December 31, 1992
Creator: Peters, E.J.
Partner: UNT Libraries Government Documents Department

Secondary natural gas recovery: Targeted applications for infield reserve growth in midcontinent reservoirs, Boonsville Field, Fort Worth Basin, Texas. Topical report, May 1993--June 1995

Description: The objectives of this project are to define undrained or incompletely drained reservoir compartments controlled primarily by depositional heterogeneity in a low-accommodation, cratonic Midcontinent depositional setting, and, afterwards, to develop and transfer to producers strategies for infield reserve growth of natural gas. Integrated geologic, geophysical, reservoir engineering, and petrophysical evaluations are described in complex difficult-to-characterize fluvial and deltaic reservoirs in Boonsville (Bend Conglomerate Gas) field, a large, mature gas field located in the Fort Worth Basin of North Texas. The purpose of this project is to demonstrate approaches to overcoming the reservoir complexity, targeting the gas resource, and doing so using state-of-the-art technologies being applied by a large cross section of Midcontinent operators.
Date: July 1, 1995
Creator: Hardage, B.A.; Carr, D.L.; Finley, R.J.; Tyler, N.; Lancaster, D.E.; Elphick, R.Y. et al.
Partner: UNT Libraries Government Documents Department

Radiative higgs boson decays H {yields} f{anti f}{gamma}

Description: Higgs boson radiative decays of the form H {r_arrow} f{ovr f}{gamma} are calculated in the Standard Model using the complete one-loop expressions for the decay amplitudes. Contributions to the radiative width from leptons and light quarks are given. We also present e{ovr e} invariant mass distributions for H {r_arrow} e{ovr e}{gamma}, which illustrate the importance of the photon pole contribution and the effects of the box diagrams. 4 refs., 6 figs.
Date: October 10, 1996
Creator: Abbasabadi, A.; Bowser-Chao, D.; Repko, W.W. & Dicus, D.A.
Partner: UNT Libraries Government Documents Department

User`s guide for UTCHEM-5.32m a three dimensional chemical flood simulator. Final report, September 30, 1992--December 31, 1995

Description: UTCHEM is a three-dimensional chemical flooding simulator. The solution scheme is analogous to IMPES, where pressure is solved for implicitly, but concentrations rather than saturations are then solved for explicitly. Phase saturations and concentrations are then solved in a flash routine. An energy balance equation is solved explicitly for reservoir temperature. The energy balance equation includes heat flow between the reservoir and the over-and under-burden rocks. The major physical phenomena modeled in the simulator are: dispersion; dilution effects; adsorption; interfacial tension; relative permeability; capillary trapping; cation exchange; phase density; compositional phase viscosity; phase behavior (pseudoquaternary); aqueous reactions; partitioning of chemical species between oil and water; dissolution/precipitation; cation exchange reactions involving more than two cations; in-situ generation of surfactant from acidic crude oil; pH dependent adsorption; polymer properties: shear thinning viscosity; inaccessible pore volume; permeability reduction; adsorption; gel properties: viscosity; permeability reduction; adsorption; tracer properties: partitioning; adsorption; radioactive decay; reaction (ester hydrolization); temperature dependent properties: viscosity; tracer reaction; gel reactions The following options are available with UTCHEM: isothermal or non-isothermal conditions, a constant or variable time-step, constant pressure or constant rate well conditions, horizontal and vertical wells, and a radial or Cartesian geometry. Please refer to the dissertation {open_quotes}Field Scale Simulation of Chemical Flooding{close_quotes} by Naji Saad, August, 1989, for a more detailed discussion of the UTCHEM simulator and its formulation.
Date: July 1, 1996
Partner: UNT Libraries Government Documents Department

A Cray T3D performance study

Description: We carry out a performance study using the Cray T3D parallel supercomputer to illustrate some important features of this machine. Timing experiments show the speed of various basic operations while more complicated operations give some measure of its parallel performance.
Date: May 1, 1996
Creator: Nallana, A. & Kincaid, D.R.
Partner: UNT Libraries Government Documents Department

User`s guide for UTCHEM implicit (1.0) a three dimensional chemical flood simulator. Final report, September 30, 1992--December 31, 1995

Description: UTCHEM IMPLICIT is a three-dimensional chemical flooding simulator. The solution scheme is fully implicit. The pressure equation and the mass conservation equations are solved simultaneously for the aqueous phase pressure and the total concentrations of each component. A third-order-in-space, second-order-in-time finite-difference method and a new total-variation-diminishing (TVD) third-order flux limiter are used to reduce numerical dispersion effects. Saturations and phase concentrations are solved in a flash routine. The major physical phenomena modeled in the simulator are: dispersion, adsorption, aqueous-oleic-microemulsion phase behavior, interfacial tension, relative permeability, capillary trapping, compositional phase viscosity, capillary pressure, phase density, polymer properties: shear thinning viscosity, inaccessible pore volume, permeability reduction, and adsorption. The following options are available in the simulator: constant or variable time-step sizes, uniform or nonuniform grid, pressure or rate constrained wells, horizontal and vertical wells.
Date: July 1, 1996
Partner: UNT Libraries Government Documents Department

On the quasihydrostatic flows of radiatively cooling self-gravitating gas clouds

Description: Two model problems are considered, illustrating the dynamics of quasihydrostatic flows of radiatively cooling, optically thin self-gravitating gas clouds. In the first problem, spherically symmetric flows in an unmagnetized plasma are considered. For a power-law dependence of the radiative loss function on the temperature, a one-parameter family of self-similar solutions is found. The authors concentrate on a constant-mass cloud, one of the cases, when the self-similarity indices are uniquely selected. In this case, the self-similar flow problem can be formally reduced to the classical Lane-Emden equation and therefore solved analytically. The cloud is shown to undergo radiative condensation, if the gas specific heat ratio {gamma} > 4/3. The condensation proceeds either gradually, or in the form of (quasihydrostatic) collapse. For {gamma} < 4/3, the cloud is shown to expand. The second problem addresses a magnetized plasma slab that undergoes quasihydrostatic radiative cooling and condensation. The problem is solved analytically, employing the Lagrangian mass coordinate.
Date: March 1, 1995
Creator: Meerson, B.; Megged, E. & Tajima, T.
Partner: UNT Libraries Government Documents Department

Spectrum of the ballooning Schroedinger equation

Description: The ballooning Schroedinger equation (BSE) is a model equation for investigating global modes that can, when approximated by a Wentzel-Kramers-Brillouin (WKB) ansatz, be described by a ballooning formalism locally to a field line. This second order differential equation with coefficients periodic in the independent variable {theta}{sub k} is assumed to apply even in cases where simple WKB quantization conditions break down, thus providing an alternative to semiclassical quantization. Also, it provides a test bed for developing more advanced WKB methods: e.g. the apparent discontinuity between quantization formulae for {open_quotes}trapped{close_quotes} and {open_quotes}passing{close_quotes} modes, whose ray paths have different topologies, is removed by extending the WKB method to include the phenomena of tunnelling and reflection. The BSE is applied to instabilities with shear in the real part of the local frequency, so that the dispersion relation is inherently complex. As the frequency shear is increased, it is found that trapped modes go over to passing modes, reducing the maximum growth rate by averaging over {theta}{sub k}.
Date: January 1, 1997
Creator: Dewar, R.L.
Partner: UNT Libraries Government Documents Department

University Reactor Sharing Program. Final report, September 30, 1992--September 29, 1994

Description: Over the past 20 years, the number of nuclear reactors on university campuses in the US declined from more than 70 to less than 40. Contrary to this trend, The University of Texas at Austin constructed a new reactor facility at a cost of $5.8 million. The new reactor facility houses a new TRIGA Mark II reactor which replaces an in-ground TRIGA Mark I reactor located in a 50-year old building. The new reactor facility was constructed to strengthen the instruction and research opportunities in nuclear science and engineering for both undergraduate and graduate students at The University of Texas. On January 17, 1992, The University of Texas at Austin received a license for operation of the new reactor. Initial criticality was achieved on March 12, 1992, and full power operation, on March 25, 1992. The UT-TRIGA research reactor provides hands-on education, multidisciplinary research and unique service activities for academic, medical, industrial, and government groups. Support by the University Reactor Sharing Programs increases the availability of The University of Texas reactor facility for use by other educational institutions which do not have nuclear reactors.
Date: January 1, 1995
Creator: Wehring, B.W.
Partner: UNT Libraries Government Documents Department

Parallel supercomputing: Advanced methods, algorithms, and software for large-scale linear and nonlinear problems. Final report, August 15, 1993--February 28, 1996

Description: This report gives a quick description of progress on methods, algorithms and software for large-scale parallel supercomputer applications. Focus is on large-scale applications of interest to DOE such as coupled viscous flow and heat or mass transport, and energy-related applications such as 3D petroleum and gas reservoir simulations on massively parallel systems. The interdisciplinary collaboration has been effective since it enhances the development of new iterative schemes for complex problems important to DOE: for example, significant advanced were made with modified forms of generalized gradient and multigrid methods for viscous flow and reservoir problems.
Date: July 1, 1996
Creator: Carey, G.F. & Young, D.M.
Partner: UNT Libraries Government Documents Department

Higgs-photon associated production at hadron colliders

Description: The authors present cross sections for the reactions p{anti p} {yields} H{gamma} and pp {yields} H{gamma} arising from the subprocess q{anti q} {yields} H{gamma}. The calculation includes the complete one-loop contribution from all light quarks and is the main source of Higgs-photon associated production in hadron colliders. At Tevatron energies, the cross section is typically 0.1 fb or less, while at LHC energies it can exceed 1.0fb.
Date: November 1, 1997
Creator: Abbasabadi, A.; Bowser-Chao, D.; Dicus, D.A. & Repko, W.W.
Partner: UNT Libraries Government Documents Department

Natural convection heat transfer within horizontal spent nuclear fuel assemblies

Description: Natural convection heat transfer is experimentally investigated in an enclosed horizontal rod bundle, which characterizes a spent nuclear fuel assembly during dry storage and/or transport conditions. The basic test section consists of a square array of sixty-four stainless steel tubular heaters enclosed within a water-cooled rectangular copper heat exchanger. The heaters are supplied with a uniform power generation per unit length while the surrounding enclosure is maintained at a uniform temperature. The test section resides within a vacuum/pressure chamber in order to subject the assembly to a range of pressure statepoints and various backfill gases. The objective of this experimental study is to obtain convection correlations which can be used in order to easily incorporate convective effects into analytical models of horizontal spent fuel systems, and also to investigate the physical nature of natural convection in enclosed horizontal rod bundles in general. The resulting data consist of: (1) measured temperatures within the assembly as a function of power, pressure, and backfill gas; (2) the relative radiative contribution for the range of observed temperatures; (3) correlations of convective Nusselt number and Rayleigh number for the rod bundle as a whole; and (4) correlations of convective Nusselt number as a function of Rayleigh number for individual rods within the array.
Date: December 1, 1995
Creator: Canaan, R.E.
Partner: UNT Libraries Government Documents Department

Photon-neutrino interactions

Description: The cross sections for the processes {gamma}{nu} {yields} {gamma}{gamma} {yields} {nu}{anti {nu}} are calculated with the aid of an effective Lagrangian derived from the Standard model. These cross sections are shown to be much larger than the elastic cross section {sigma}({gamma}{nu} {yields} {gamma}{nu}) for photon energies {omega} {ge} 1 keV. Possible astrophysical implications are discussed.
Date: December 1, 1997
Creator: Dicus, D.A. & Repko, W.W.
Partner: UNT Libraries Government Documents Department

Intel equipment for Rice University consortium member of ORNL partnership in computational science

Description: A 56 node (with 16 megabytes per processor) Intel Paragon was purchased in part under this grant and installed at rice University. Before acceptance, Rice and INTEL reached an agreement for trading in 16 nodes for additional memory; 32 megabytes for each of the 40 nodes. In August 1995, the machine was moved to The University of Texas at Austin (UT Austin) with Wheeler and members of the Center for Subsurface Modeling. The author gives a brief list of accomplishments by members of the Center for Subsurface Modeling at UT Austin.
Date: April 1, 1998
Creator: Wheeler, M.
Partner: UNT Libraries Government Documents Department

A portable and independent edge fluctuation diagnostics. Technical progress report, November 1, 1994--September 14, 1995

Description: The consolidation of edge plasma parameters into a database allows comparisons between experiment and predictions of theoretical models over a wide range of parameters. In this way we hope to validate (or refute) various proposed driving mechanisms for the observed turbulence and transport and to derive empirical scaling laws for parameters useful in machine design, such as e-folding lengths, fluxes and effective diffusion coefficients.
Date: July 1, 1994
Creator: Wootton, A.J.
Partner: UNT Libraries Government Documents Department

Development of cost-effective surfactant flooding technology, Quarterly report, October 1995--December 1995

Description: The objective of this research is to develop cost-effective surfactant flooding technology by using simulation studies to evaluate and optimize alternative design strategies taking into account reservoir characteristics process chemistry, and process design options such as horizontal wells. Task 1 is the development of an improved numerical method for our simulator that will enable us to solve a wider class of these difficult simulation problems accurately and affordably. Task 2 is the application of this simulator to the optimization of surfactant flooding to reduce its risk and cost. In this quarter, we have continued working on Task 2 to optimize surfactant flooding design and have included economic analysis to the optimization process. An economic model was developed using a spreadsheet and the discounted cash flow (DCF) method of economic analysis. The model was designed specifically for a domestic onshore surfactant flood and has been used to economically evaluate previous work that used a technical approach to optimization. The DCF model outputs common economic decision making criteria, such as net present value (NPV), internal rate of return (IRR), and payback period.
Date: December 31, 1995
Creator: Pope, G.A. & Sepehrnoori, K.
Partner: UNT Libraries Government Documents Department

Coordinates of the quantum plane as q-tensor operators in U{sub q} (su(2) * su(2))

Description: The relation between the set of transformations M{sub q}(2) of the quantum plane and the quantum universal enveloping algebra U{sub q}(u(2)) is investigated by constructing representations of the factor algebra U{sub q} (u(2) * u(2)). The non-commuting coordinates of M{sub q}(2), on which U{sub q}(2) * U{sub q}(2) acts, are realized as q-spinors with respect to each U{sub q}(u(2)) algebra. The representation matrices of U{sub q}(2) are constructed as polynomials in these spinor components. This construction allows a derivation of the commutation relations of the noncommuting coordinates of M{sub q}(2) directly from properties of U{sub q}(u(2)). The generalization of these results to U{sub q}(u(n)) and M{sub q}(n) is also discussed.
Date: January 13, 1995
Creator: Biedenharn, L.C. & Lohe, M.A.
Partner: UNT Libraries Government Documents Department

Revitalizing a mature oil play: Strategies for finding and producing unrecovered oil in frio fluvial-deltaic sandstone reservoirs at South Texas. Annual report, October 1994--October 1995

Description: The Frio Fluvial-Deltaic Sandstone oil play of South Texas has produced nearly 1 billion barrels of oil, yet it still contains about 1.6 billion barrels of unrecovered mobile oil and nearly the same amount of residual oil resources. Interwell-scale geologic facise models of Frio Fluvial-deltaic reservoirs are being combined with engineering assessments and geophysical evaluations in order to determine the controls that these characteristics exert on the location and volume or unrecovered mobile and residual oil. Progress in the third year centered on technology transfer. An overview of project tasks is presented.
Date: February 1, 1996
Creator: Holtz, M.; Knox, P. & McRae, L.
Partner: UNT Libraries Government Documents Department