A corrected and generalized successive random additions algorithm for simulating fractional levy motions (open access)

A corrected and generalized successive random additions algorithm for simulating fractional levy motions

Simulation of subsurface heterogeneity is important for modeling subsurface flow and transport processes. Previous studies have indicated that subsurface property variations can often be characterized by fractional Brownian motion (fBm) or (truncated) fractional Levy motion (fLm). Because Levy-stable distributions have many novel and often unfamiliar properties, studies on generating fLm distributions are rare in the literature. In this study, we generalize a relatively simple and computationally efficient successive random additions (SRA) algorithm, originally developed for generating Gaussian fractals, to simulate fLm distributions. We also propose an additional important step in response to continued observations that the traditional SRA algorithm often generates fractal distributions having poor scaling and correlation properties. Finally, the generalized and modified SRA algorithm is validated through numerical tests.
Date: May 29, 2002
Creator: Liu, Hui-Hai; Bodvarsson, Gudmundur S.; Lu, Silong & Molz, Fred J.
Object Type: Article
System: The UNT Digital Library
Flow Tones in a Pipeline-Cavity System: Effect of Pipe Asymmetry (open access)

Flow Tones in a Pipeline-Cavity System: Effect of Pipe Asymmetry

Flow tones in a pipeline-cavity system are characterized in terms of unsteady pressure within the cavity and along the pipe. The reference case corresponds to equal lengths of pipe connected to the inlet and outlet ends of the cavity. Varying degrees of asymmetry of this pipe arrangement are investigated. The asymmetry is achieved by an extension of variable length, which is added to the pipe at the cavity outlet. An extension length as small as a few percent of the acoustic wavelength of the resonant mode can yield a substantial reduction in the pressure amplitude of the flow tone. This amplitude decrease occurs in a similar fashion within both the cavity and the pipe resonator, which indicates that it is a global phenomenon. Furthermore, the decrease of pressure amplitude is closely correlated with a decrease of the Q (quality)-factor of the predominant spectral component of pressure. At a sufficiently large value of extension length, however, the overall form of the pressure spectrum recovers to the form that exists at zero length of the extension. Further insight is provided by variation of the inflow velocity at selected values of extension length. Irrespective of its value, both the magnitude and frequency of …
Date: May 29, 2002
Creator: Erdem, D.; rockwell, D.; Oshkai, P. & Pollack, M.
Object Type: Report
System: The UNT Digital Library
Analytic studies of the long range beam-beam tune shifts and chromaticities (open access)

Analytic studies of the long range beam-beam tune shifts and chromaticities

A formula is derived, which allows efficient analytical evaluation of the long range beam-beam tune shifts and chromaticities with amplitude. It assumes that the beams are infinitely short, oppositely charged, and with Gaussian transversal profile. The formula employs an infinite sum with favorable convergence rates, making it well suited especially for the long range case. For a deeper understanding of the beam-beam effects, the structure of the formula was analyzed. It is shown that the tune shifts and chromaticities change sign at certain values of the separation and/or amplitude, and folds in the footprints are predicted. Some special cases were studied in more detail. Applications to the Tevatron are presented, including some proposed compensation schemes.
Date: May 29, 2002
Creator: Erdelyi, Bela & Sen, Tanaji
Object Type: Report
System: The UNT Digital Library
Calibration of Seismic Attributes for Reservoir Characterization (open access)

Calibration of Seismic Attributes for Reservoir Characterization

This project is intended to enhance the ability to use seismic data for the determination of rock and fluid properties through an improved understanding of the physics underlying the relationships between seismic attributes and formation.
Date: May 29, 2002
Creator: Pennington, Wayne D.
Object Type: Report
System: The UNT Digital Library
Jet physics at the Tevatron (open access)

Jet physics at the Tevatron

Recent analyses by the CDF and D0 Collaborations of jet data produced in p{bar p} collisions at the Fermilab Tevatron Collider are presented. These include new studies of the inclusive jet production cross section, a measurement of the strong coupling constant, the first measurement of subjet multiplicity of quark and gluon jets, examination of ratios of multijet cross sections and their implications for choice of renormalization scale, and a study of charged jet evolution and energy flow in the underlying event. The results are compared to theoretical predictions.
Date: May 29, 2002
Creator: Seidel, S.
Object Type: Article
System: The UNT Digital Library
Recent CDF and D0 Run I results (open access)

Recent CDF and D0 Run I results

We summarize some of the most recent CDF and D0 results from the 1992-1995 collider run at the Fermilab Tevatron. These include a detailed examination of the heavy flavor content of W+jet data made by CDF. We found in this study that the rate and the kinematic properties of the event subsample, featuring soft lepton and secondary vertex in the same jet, are statistically difficult to accommodate with the Standard Model simulation. CDF has also searched for new physics in events with a photon, a lepton and E{sub T}. Finally, the results of the two collaborations in their search for the first, second and third generations leptoquarks are presented.
Date: May 29, 2002
Creator: Velev, G.
Object Type: Article
System: The UNT Digital Library
Electron-cloud updated simulation results for the PSR, and recent results for the SNS (open access)

Electron-cloud updated simulation results for the PSR, and recent results for the SNS

Recent simulation results for the main features of the electron cloud in the storage ring of the Spallation Neutron Source (SNS) at Oak Ridge, and updated results for the Proton Storage Ring (PSR) at Los Alamos are presented in this paper. A refined model for the secondary emission process including the so called true secondary, rediffused and backscattered electrons has recently been included in the electron-cloud code.
Date: May 29, 2002
Creator: Pivi, M. & Furman, M. A.
Object Type: Article
System: The UNT Digital Library
''Whither Deterrence?'' A Brief Synopsis May, 2002 (open access)

''Whither Deterrence?'' A Brief Synopsis May, 2002

To most audiences, deterrence has been interconnected with nuclear weapons whose purpose had been to deter a Soviet attack. But, the Soviet Union has been gone for almost a decade. President George W. Bush has stated that Russia is not an enemy of the US and the numbers of nuclear weapons can be dramatically reduced. It is important to note that deterrence has always transcended nuclear weapons. The US' first line of deterrence has been its formidable conventional warfare capability, designed to prevent conflict and win wars if necessary. The role of nuclear weapons has been to deter the,use of nuclear weapons and other weapons of mass destruction against U.S. interests during the conduct of conventional warfare and to ensure our ability to inflict massive destruction on any who would use nuclear weapons, or other weapons of mass destruction, against us. With regard to the Soviet Union, the threat of the use of nuclear weapons was a critical component of our deterrent to prevent massive Soviet conventional attack against our allies in Europe. However, the events of September 11, 2001 make clear that we have not convinced all who seek to harm us that we will be able to respond …
Date: May 29, 2002
Creator: Poppe, C; Vergino, E; Barker, R; Brown, P; Gilmartin, T J; Nach, M et al.
Object Type: Report
System: The UNT Digital Library
Building 251 Radioactive Waste Characterization by Process Knowledge (open access)

Building 251 Radioactive Waste Characterization by Process Knowledge

Building 251 is the Lawrence Livermore National Laboratory Heavy Elements Facility. Operations that involved heavy elements with uncontained radioisotopes including transuranic elements took place inside of glove boxes and fume hoods. These operations included process and solution chemistry, dissolutions, titrations, centrifuging, etc., and isotope separation. Operations with radioactive material which presently take place outside of glove boxes include storage, assaying, packing and unpacking and inventory verification. Wastes generated inside glove boxes will generally be considered TRU or Greater Than Class C (GTCC). Wastes generated in the RMA, outside glove boxes, is presumed to be low level waste. This process knowledge quantification method may be applied to waste generated anywhere within or around B251. The method is suitable only for quantification of waste which measures below the MDA of the Blue Alpha meter (i.e. only material which measures as Non-Detect with the blue alpha is to be characterized by this method).
Date: May 29, 2002
Creator: Dominick, J L
Object Type: Report
System: The UNT Digital Library
Precipitation of Aluminum Containing Species in Tank Wastes (open access)

Precipitation of Aluminum Containing Species in Tank Wastes

Aluminisilicate deposit buildup experienced during the tank waste volume-reduction process at the Savannah River Site (SRS) required an evaporator to be shut down in October 1999. The Waste Processing Technology Section (WPTS) of Westinghouse Savannah River Company at SRS is now collaborating with team members from Pacific Northwest National Laboratory (PNNL) to verify the steady-state thermodynamic stability of aluminosilicate compounds under waste tank conditions in an attempt to eliminate the deposition and clogging problems. The data obtained at 40 ?C showed that formation and persistence of crystalline phases was dependent on the initial hydroxide concentrations. The formation and persistence of zeolite A occurred only at lower hydroxide concentrations, whereas increasing hydroxide concentrations appeared to promote the formation of sodalite and cancrinite. The data also showed that although zeolite A forms initially, it is a metastable phase that converts to more stable crystalline materials such as sodalite and cancrinite. Additionally, the rate of transformation of zeolite A appeared to increase with increasing hydroxide concentration. The data from tests conducted at 80 ?C revealed relatively rapid formation of sodalite and cancrinite. Although minor amounts of zeolite A were initially detected in some cases, the higher reaction temperatures seemed to promote very rapid …
Date: May 29, 2002
Creator: Mattigod, Shas V.; Hobbs, David; Parker, Kent E. & McCready, David E.
Object Type: Report
System: The UNT Digital Library
Investigations and Recommendations on the Use of Existing Experiments in Criticality Safety Analysis of Nuclear Fuel Cycle Facilities for Weapons-Grade Plutonium (open access)

Investigations and Recommendations on the Use of Existing Experiments in Criticality Safety Analysis of Nuclear Fuel Cycle Facilities for Weapons-Grade Plutonium

Sensitivity and Uncertainty (S/U) methods, recently developed at Oak Ridge National Laboratory (ORNL) have been demonstrated to determine the applicability of critical benchmark experiments to the criticality code validation of design systems. These methods, although still under development, have been recently published in several sources. Development of the techniques used in this report was conducted through joint support from the United States Department of Energy (U.S. DOE) and the Nuclear Regulatory Commission (NRC) to provide a physics-based approach for the establishment of the area of applicability of critical experiments per the requirements of ANSI/ANS-8.1. Use of these methods may allow users to interpolate and extrapolate the traditional area of applicability (AOA) of a given set of critical experiments to include new application areas that may not have been anticipated during the experiment design. The new S/U analytical tools include the SEN1 and SEN3 sensitivity analysis sequences, which will be available with the next release of the Standardized Computer Analyses for Licensing Evaluation (SCALE) code system. These analysis sequences compute the relative change in the system neutron multiplication factor, k{sub eff}, which would be observed for perturbations in the group-wise neutron cross-section data for each reaction of each nuclide in the …
Date: May 29, 2002
Creator: Rearden, B. T. & Elam, K. R.
Object Type: Report
System: The UNT Digital Library
Tevatron bunch length studies at CDF (open access)

Tevatron bunch length studies at CDF

A luminous interaction region can be described by the distribution in (x, y, z) over which p{bar p} interactions are observed in a detector. The spatial size of this distribution can be written in terms of expressions that involve only combinations of the proton and anti-proton bunch sizes. Hence, it is not possible to determine the sizes of the proton and anti-proton bunches independently by fitting the distribution of (x, y, z) from the recorded events. If, in addition to the coordinates (x, y, z) at which p{bar p} interactions occur, the times at which the interactions took place are also measured, then it becomes possible to measure the lengths of the proton and anti-proton bunches separately. This sensitivity is due to a correlation between z and t that arises from the fact that the proton and anti-proton bunches travel in opposite directions. The derivation presented in section 2 quantifies this correlation, resulting in an expression for the probability density as a function of z and t for p{bar p} interactions. By fitting the distributions observed at CDF using this model, we measure the lengths of the proton and anti-proton bunches at times throughout several Tevatron stores. From this analysis …
Date: May 29, 2002
Creator: Jones, Matthew; Kephart, Bob & Vidal, and Rick
Object Type: Report
System: The UNT Digital Library
Reduction and Immobilization of Radionuclides and Toxic Metal Ions Using Combined Zero Valent Iron and Anaerobic Bacteria (open access)

Reduction and Immobilization of Radionuclides and Toxic Metal Ions Using Combined Zero Valent Iron and Anaerobic Bacteria

The use of zero valent iron, permeable reactive barriers (PRBs) for groundwater remediation continues to increase. AN exciting variation of this technology involves introducing anaerobic bacteria into these barriers so that both biological and abiotic pollutant removal processes are functional. This work evaluated the hypothesis that a system combining a mixed culture of sulfate reducing bacteria (SRB) with zero valent iron would have a greater cr(VI) removal efficiency and a greater total Cr(VI) removal capacity than a zero valent iron system without the microorganisms. Hence, the overall goal of this research was to compare the performance of these types of systems with regard to their Cr(VI) removal efficiency and total Cr(VI) removal capacity. Both batch and continuous flow reactor systems were evaluated.
Date: May 29, 2002
Creator: Weathers, Lenly J. & Katz, Lynn E.
Object Type: Report
System: The UNT Digital Library
Neutronics Benchmarks for the Utilization of Mixed-Oxide Fuel: Joint U.S./Russian Progress Report for Fiscal Year 1997 Volume 2-Calculations Performed in the United States (open access)

Neutronics Benchmarks for the Utilization of Mixed-Oxide Fuel: Joint U.S./Russian Progress Report for Fiscal Year 1997 Volume 2-Calculations Performed in the United States

This volume of the progress report provides documentation of reactor physics and criticality safety studies conducted in the US during fiscal year 1997 and sponsored by the Fissile Materials Disposition Program of the US Department of Energy. Descriptions of computational and experimental benchmarks for the verification and validation of computer programs for neutron physics analyses are included. All benchmarks include either plutonium, uranium, or mixed uranium and plutonium fuels. Calculated physics parameters are reported for all of the computational benchmarks and for those experimental benchmarks that the US and Russia mutually agreed in November 1996 were applicable to mixed-oxide fuel cycles for light-water reactors.
Date: May 29, 2002
Creator: Primm III, RT
Object Type: Report
System: The UNT Digital Library
CDF Run 1 diffractive results (open access)

CDF Run 1 diffractive results

Results on soft and hard diffraction obtained by the CDF Collaboration in Run 1 of the Fermilab Tevatron {bar p}p collider are presented. Comparisons are made with theoretical predictions and with results from the DESY ep collider HERA.
Date: May 29, 2002
Creator: Hakakeyama, K.
Object Type: Article
System: The UNT Digital Library
3D Extended Logging for Geothermal Resources: Field Trials with the Geo-Bilt System (open access)

3D Extended Logging for Geothermal Resources: Field Trials with the Geo-Bilt System

Geo-BILT (Geothermal Borehole Induction Logging Tool) is an extended induction logging tool designed for 3D resistivity imaging around a single borehole. The tool was developed for deployment in high temperature geothermal wells under a joint program funded by the California Energy Commission, Electromagnetic Instruments (EMI) and the U.S. Department of Energy. EM1 was responsible for tool design and manufacture, and numerical modeling efforts were being addressed at Lawrence Livermore Laboratory (LLNL) and other contractors. The field deployment was done by EM1 and LLNL. The tool operates at frequencies from 2 to 42 kHz, and its design features a series of three-component magnetic sensors offset at 2 and 5 meters from a three-component magnetic source. The combined package makes it possible to do 3D resistivity imaging, deep into the formation, from a single well. The manufacture and testing of the tool was completed in spring of 2001, and the initial deployment of Geo-BILT occurred in May 2001 at the Lost Hills oil field in southern California at leases operated by Chevron USA. This site was chosen for the initial field test because of the favorable geological conditions and the availability of a number of wells suitable for tool deployment. The second …
Date: May 29, 2002
Creator: Mallan, Robert; Wilt, Michael; Kirkendall, Barry & Kasameyer, Paul
Object Type: Article
System: The UNT Digital Library