Programmers Manual for the PVM Coupling Interface in RELAP5-3D (open access)

Programmers Manual for the PVM Coupling Interface in RELAP5-3D

This report describes the implementation of the PVM API in the RELAP5-3D© computer code. The information in the report is intended for programmers wanting to correct or extend RELAP5-3D©.
Date: March 1, 2005
Creator: Weaver, Walter L., III
Object Type: Report
System: The UNT Digital Library
Finite Difference Modeling of Wave Progpagation in Acoustic TiltedTI Media (open access)

Finite Difference Modeling of Wave Progpagation in Acoustic TiltedTI Media

Based on an acoustic assumption (shear wave velocity is zero) and a dispersion relation, we derive an acoustic wave equation for P-waves in tilted transversely isotropic (TTI) media (transversely isotropic media with a tilted symmetry axis). This equation has fewer parameters than an elastic wave equation in TTI media and yields an accurate description of P-wave traveltimes and spreading-related attenuation. Our TTI acoustic wave equation is a fourth-order equation in time and space. We demonstrate that the acoustic approximation allows the presence of shear waves in the solution. The substantial differences in traveltime and amplitude between data created using VTI and TTI assumptions is illustrated in examples.
Date: March 21, 2005
Creator: Zhang, Linbin; Rector, James W., III & Hoversten, G. Michael
Object Type: Article
System: The UNT Digital Library
Simulation of a Batch Chemical Process Using Parallel Computing with PVM and Speedup (open access)

Simulation of a Batch Chemical Process Using Parallel Computing with PVM and Speedup

Speedup, a commercial software package for the dynamic modeling of chemical processes, has been coupled with the PVM software to allow a single process model to be distributed over several computers running in parallel. As an initial application, this coarse distribution technique was applied to a batch chemical plant containing 16 unit operations. Computation time for this problem was reduced by a factor of 4.7 using only three parallel processors in the UNIX computing environment. Better than linear acceleration was achieved from the significant reduction in computation required to reinitialize the smaller subprocesses at discontinuities in the solution. The process was physically divided at points that naturally separated the overall plant into distinct subprocesses. This facilitated the computation by minimizing the interconnection between the parallel units. Techniques were developed to make efficient material and energy transfers between the modeled subprocesses based on actual material transfers used in plant operations.
Date: March 25, 2003
Creator: Smith, F. G., III
Object Type: Article
System: The UNT Digital Library
Urban Wood/Coal Co-Firing in the Bellefield Boilerplant (open access)

Urban Wood/Coal Co-Firing in the Bellefield Boilerplant

During the second quarter, important preparatory work was continued so that the experimental activities can begin toward the end of the third quarter or early in the fourth quarter. The Environmental Questionnaire was submitted to the U.S. DOE National Energy Technology Laboratory (NETL), after thorough review by the Bellefield Boiler Plant (BBP). Letters were submitted to the Allegheny County Health Department (ACHD) and the Pennsylvania Department of Environmental Protection (PADEP) to seek R and D variances for permits at the BBP, the J. A. Rutter Company (JARC), and Emery Tree Service (ETS) for their portion of the project. Memoranda of understanding were executed by the University of Pittsburgh (University) with the BBP, JARC and ETS. Construction wood was collected from Thompson Properties. Discussions were held with the BBP and Energy Systems Associates (ESA), the BBP's engineering consultant. Presentations describing the University of Pittsburgh Wood/Coal Co-Firing Program were provided to the American Chemical Society (ACS), the Federal Energy Management Program (FEMP), the Upgraded Coal Interest Group (UCIG) of the Electric Power Research Institute (EPRI), the Engineering Center for Environment and Energy (ECEE) of the University of Pittsburgh, the Pittsburgh Coal Conference (PCC), the Pennsylvania Ethanol Workshop, BioEnergy 2000 and the Kick-Off …
Date: March 7, 2001
Creator: Cobb, James T., Jr.; Geiger, Gene E. & III, William W. Elder
Object Type: Report
System: The UNT Digital Library
Liquid/vapor surface tension of metals: Embedded atom method with charge gradient corrections (open access)

Liquid/vapor surface tension of metals: Embedded atom method with charge gradient corrections

Molecular dynamics (MD) simulations for three separately parameterized embedded atom methods (EAM) function sets are used to determine the liquid/vapor surface tension {gamma} for Al, Ni, Cu, Ag, and Au. The three EAM models differ in both the functional forms employed and the fitting procedure used. All the EAM potentials underestimate {gamma} but one of the models performs consistently better than the others. The authors show that including a correction to the local charge density associated with gradients in the density together with exploiting the invariance of the EAM bulk potential to appropriate transformations in the charge density can lead to improved values for {gamma}, as well as for solid free surface energies, within existing EAM function sets.
Date: March 21, 2000
Creator: Webb, Edmund B., III & Grest, Gary S.
Object Type: Article
System: The UNT Digital Library
Attempt to confirm superheavy element production in the 48Ca +238U reaction (open access)

Attempt to confirm superheavy element production in the 48Ca +238U reaction

An attempt to confirm production of superheavy elements in the reaction of 48Ca beams with actinide targets has been performed using the 238U(48Ca,3n)283112 reaction. Two 48Ca projectile energies were used, that spanned the energy range where the largest cross sections have been reported for this reaction. No spontaneous fission events were observed. No alpha decay chains consistent with either reported or theoretically predicted element 112 decay properties were observed. The cross section limits reached are significantly smaller than the recently reported cross sections.
Date: March 24, 2005
Creator: Gregorich, K. E.; Loveland, W.; Peterson, D.; Zielinski, P. M.; Nelson, S. L.; Chung, Y. H. et al.
Object Type: Article
System: The UNT Digital Library
The cyro-thermochromatographic separator (CTS): A new detectionand separation system for highly volatile osmium and hassium (element108) tetroxides (open access)

The cyro-thermochromatographic separator (CTS): A new detectionand separation system for highly volatile osmium and hassium (element108) tetroxides

We implemented a new concept for heavy element chemistry research using an ion separator to separate the desired products from the beam, transfer products and other undesirable by-products prior to chemical studies. First, a Recoil product Transfer Chamber (RTC) was designed and attached to the Berkeley Gas-filled Separator (BGS) to collect and transfer the recoiling products to the chemical separation system. The RTC consists of a wire-grid-supported thin mylar foil ({le}) 200 {micro}g/cm{sup 2} that separates the BGS detector chamber, at 1.3 mbar pressure, from the chemistry system at different pressures ranging from 480 mbar to 2000 mbar. The overall transport efficiency ranged between 30% and 15%, compared to the activity measured in the focal plane detector of the BGS. The CTS was designed as a separation and {alpha}-decay detection system for the highly volatile tetroxides of osmium and hassium, element 108. The CTS, shown in figure 1, consists of two rows of 32-{alpha} detectors arranged along a negative temperature gradient. The tetroxides adsorb on the surface of one of the silicone photodiodes at a certain deposition temperature, and the nuclide is then identified by the {alpha}-decay. To test the CTS with the expected hassium homologue osmium, different {alpha}-active osmium …
Date: March 8, 2002
Creator: Kirbach, U. W.; Folden, C. M., III; Ginter, T. N.; Gregorich, K. E.; Lee, D. M.; Ninov, V. et al.
Object Type: Article
System: The UNT Digital Library
Highly Mismatched Alloys for Intermediate Band Solar Cells (open access)

Highly Mismatched Alloys for Intermediate Band Solar Cells

It has long been recognized that the introduction of a narrow band of states in a semiconductor band gap could be used to achieve improved power conversion efficiency in semiconductor-based solar cells. The intermediate band would serve as a ''stepping stone'' for photons of different energy to excite electrons from the valence to the conduction band. An important advantage of this design is that it requires formation of only a single p-n junction, which is a crucial simplification in comparison to multijunction solar cells. A detailed balance analysis predicts a limiting efficiency of more than 50% for an optimized, single intermediate band solar cell. This is higher than the efficiency of an optimized two junction solar cell. Using ion beam implantation and pulsed laser melting we have synthesized Zn{sub 1-y}Mn{sub y}O{sub x}Te{sub 1-x} alloys with x<0.03. These highly mismatched alloys have a unique electronic structure with a narrow oxygen-derived intermediate band. The width and the location of the band is described by the Band Anticrossing model and can be varied by controlling the oxygen content. This provides a unique opportunity to optimize the absorption of solar photons for best solar cell performance. We have carried out systematic studies of the …
Date: March 21, 2005
Creator: Walukiewicz, W.; Yu, K. M.; Wu, J.; Ager, J. W., III; Shan, W.; Scrapulla, M. A. et al.
Object Type: Article
System: The UNT Digital Library
Effect of oxygen on the electronic band structure in ZnO{sub x}Se{sub 1-x} alloys (open access)

Effect of oxygen on the electronic band structure in ZnO{sub x}Se{sub 1-x} alloys

The effect of alloying small amounts of ZnO with ZnSe on the electronic band structure has been studied. Optical transitions in molecular-beam-epitaxy-grown ZnO{sub x}Se{sub 1-x} epitaxial films (0 {<=} x {<=} 1.35%) were investigated using photoreflectance and photoluminescence spectroscopies. The fundamental band-gap energy of the alloys was found to decrease at a rate of about 0.1 eV per atomic percent of oxygen. The pressure dependence of the band gap was also found to be strongly affected by O incorporation. Both the effects can be quantitatively explained by an anticrossing interaction between the extended states of the conduction band of ZnSe and the highly localized oxygen states located at approximately 0.22 eV above the conduction-band edge.
Date: March 14, 2003
Creator: Shan, W.; Walukiewicz, W.; Ager, J. W., III; Yu, K. M.; Wu, J.; Haller, E. E. et al.
Object Type: Article
System: The UNT Digital Library
Comparison of Implicit and Symbolic Implicit Monte Carlo Line Transport With Frequency Weight Vector Extension (open access)

Comparison of Implicit and Symbolic Implicit Monte Carlo Line Transport With Frequency Weight Vector Extension

We compare the Implicit Monte Carlo (IMC) technique to the Symbolic IMC (SIMC) technique, with and without weight vectors in frequency space, for time-dependent line transport in the presence of collisional pumping. We examine the efficiency and accuracy of the IMC and SIMC methods for examples involving the evolution of a collisionally pumped trapping problem to steady-state, the surface heating of cold media by a beam, and the diffusion of energy from a localized region that is collisionally pumped. The importance of spatial biasing and teleportation for problems involving high opacity is demonstrated. Our numerical solution, along with its associated teleportation error, is checked against theoretical calculations for the last example.
Date: March 20, 2002
Creator: McKinley, M. S.; Brooks, E. D., III & Szoke, A.
Object Type: Report
System: The UNT Digital Library
Kinetic measurement and prediction of the hydrogen outgassing from the polycrystalline LiH/LiOH system (open access)

Kinetic measurement and prediction of the hydrogen outgassing from the polycrystalline LiH/LiOH system

In this report, we present the use of temperature programmed reaction/decomposition (TPR) in the isoconversion mode to measure outgassing kinetics and to make kinetic prediction concerning hydrogen release from the polycrystalline LiH/LiOH system in the absence of any external H{sub 2}O source.
Date: March 9, 2005
Creator: Dinh, L. N.; Grant, D. M.; Schildbach, M. A.; Smith, R. A.; Leckey, J. H.; Siekhaus, W. J. et al.
Object Type: Article
System: The UNT Digital Library
Sequestering Carbon Dioxide in Coalbeds (open access)

Sequestering Carbon Dioxide in Coalbeds

The authors' long-term goal is to develop accurate prediction methods for describing the adsorption behavior of gas mixtures on solid adsorbents over complete ranges of temperature, pressure and adsorbent types. The originally-stated, major objectives of the current project are to (1) measure the adsorption behavior of pure CO{sub 2}, methane, nitrogen, and their binary and ternary mixtures on several selected coals having different properties at temperatures and pressures applicable to the particular coals being studied, (2) generalize the adsorption results in terms of appropriate properties of the coals to facilitate estimation of adsorption behavior for coals other than those studied experimentally, (3) delineate the sensitivity of the competitive adsorption of CO{sub 2}, methane and nitrogen to the specific characteristics of the coal on which they are adsorbed; establish the major differences (if any) in the nature of this competitive adsorption on different coals, and (4) test and/or develop theoretically-based mathematical models to represent accurately the adsorption behavior of mixtures of the type for which measurements are made. As this project has developed, an important additional objective has been added to the above original list. Namely, we have been encouraged to interact with industry and/or governmental agencies to utilize our expertise …
Date: March 10, 2003
Creator: Gasem, K. A. M.; Robinson, R. L., Jr. & Radovic, L. R.
Object Type: Report
System: The UNT Digital Library
Petroleum Biorefining for Pollution Prevention (open access)

Petroleum Biorefining for Pollution Prevention

The objective of this project was to isolate and characterize thermophilic bacterial cultures that can be used for the selective removal of nitrogen, sulfur, and/or metals in the biorefining of petroleum. The project was completed on schedule and no major difficulties were encountered. Significant progress was made on multiple topics relevant to the development of a petroleum biorefining process capable of operating at thermophilic temperatures. New cultures capable of selectively cleaving C-N or C-S bonds in molecules relevant to petroleum were obtained, and the genes encoding the enzymes for these unique biochemical reactions were cloned and sequenced. Genetic tools were developed that enable the use of Thermus thermophilus as a host to express any gene of interest, and information was obtained regarding the optimum conditions for the growth of T. thermophilus. The development of a practical biorefining process still requires further research and the future research needs identified in this project include the development of new enzymes and pathways for the selective cleavage of C-N or C-S bonds that have higher specific activities, increased substrate range, and are capable of functioning at thermophilic temperatures. Additionally, there is a need for process engineering research to determine the maximum yield of biomass …
Date: March 1, 2002
Creator: Kilbane, John J., II
Object Type: Report
System: The UNT Digital Library
The Effect of Thermo-mechanical Processing on the Mechanical Properties of Molybdenum-2 Volume%Lanthana (open access)

The Effect of Thermo-mechanical Processing on the Mechanical Properties of Molybdenum-2 Volume%Lanthana

Variations in oxide species and consolidation method have been shown to have a significant effect on the mechanical properties of oxide dispersion strengthened (ODS) molybdenum material. The mechanical behavior of molybdenum - 2 Volume % La[sub]2O[sub]3 mill product forms, produced by a wet doping process, were characterized over the temperature range of -150 degrees C to 1800 degrees C. The various mill product forms evaluated ranged from thin sheet stock to bar stock. Tensile properties of the material in the various product forms were not significantly affected by the vast difference in total cold work. Creep properties, however, were sensitive to the total amount of cold work as well as the starting microstructure. Stress-relieved material had superior creep rupture properties to recrystallized material at 1200 degrees C, while at 1500 degrees C and above the opposite was observed. Thus it is necessary to match the appropriate thermo-mechanical processing and microstructure of molybdenum - 2 volume % LA[sub]2O[sub]3 to the demands of the application being considered.
Date: March 14, 2001
Creator: Mueller, A. J.; Buckman, R. W., Jr. & Shields, A. J., Jr
Object Type: Article
System: The UNT Digital Library
Recent Advancements in Microwave Imaging Plasma Diagnostics (open access)

Recent Advancements in Microwave Imaging Plasma Diagnostics

Significant advances in microwave and millimeter wave technology over the past decade have enabled the development of a new generation of imaging diagnostics for current and envisioned magnetic fusion devices. Prominent among these are revolutionary microwave electron cyclotron emission imaging (ECEI), microwave phase imaging interferometers, imaging microwave scattering and microwave imaging reflectometer (MIR) systems for imaging electron temperature and electron density fluctuations (both turbulent and coherent) and profiles (including transport barriers) on toroidal devices such as tokamaks, spherical tori, and stellarators. The diagnostic technology is reviewed, and typical diagnostic systems are analyzed. Representative experimental results obtained with these novel diagnostic systems are also presented.
Date: March 26, 2002
Creator: Park, H.; Chang, C. C.; Deng, B. H.; Domier, C. W.; Donni, A. J. H.; Kawahata, K. et al.
Object Type: Report
System: The UNT Digital Library
Development and Manufacture of Cost Effective Composite Drill Pipe (open access)

Development and Manufacture of Cost Effective Composite Drill Pipe

This technical report presents the engineering research and data accomplishments that have transpired to date in support of the development of Cost Effective Composite Drill Pipe (CDP). The report presents accomplishments made from October 1, 2002 through September 30, 2003. The following have been accomplished and are reported in detail herein: Metal-to-Composite Interface (MCI) redesign and testing; Successful demonstration of MCI connection for both SR and ER/DW CDP; Specifications for a 127mm (5 inch) ID by 152.4 mm (6 inch) OD composite drill pipe have been finalized for Extended Reach/Deep Water applications (ER/DW); Field testing of Short Radius CDP (SR); Sealing composite laminate to contain high pressure; Amendments; Amendment for ''Smart'' feature added to ER/DW development along with time and funding to complete battery of qualification tests with option for field demonstration; and Preparation of papers for publication and conference presentations.
Date: March 30, 2003
Creator: Leslie, James C.; Leslie, James C., II; Truong, Lee & Heard, James T.
Object Type: Report
System: The UNT Digital Library
Development and Manufacture of Cost Effective Composite Drill Pipe (open access)

Development and Manufacture of Cost Effective Composite Drill Pipe

This technical report presents the engineering research, process development and data accomplishments that have transpired to date in support of the development of Cost Effective Composite Drill Pipe (CDP). The report presents progress made from October 1, 2003 through September 30, 2004 and contains the following discussions: (1) Direct Electrical Connection for Rotary Shoulder Tool Joints; (2) Conductors for inclusion in the pipe wall (ER/DW-CDP); (3) Qualify fibers from Zoltek; (4) Qualify resin from Bakelite; (5) First commercial order for SR-CDP from Integrated Directional Resources (SR-CDP); and (6) Preparation of papers for publication and conference presentations.
Date: March 18, 2005
Creator: Leslie, James C.; Leslie, James C., II; Truong, Lee; Heard, James T. & Manekas, Peter
Object Type: Report
System: The UNT Digital Library
Addition of Tomographic Capabilities to NMIS (open access)

Addition of Tomographic Capabilities to NMIS

This paper describes tomographic capabilities for the Nuclear Materials Identification System (NMIS). The tomographic capabilities add weapons component spatial and material properties information that result in a more detailed item signature (template) and provide more information for physical attributes analyses. The Nuclear Materials Identification System (NMIS) is used routinely to confirm the identity of HEU components in sealed containers. It does this through a radiation signature acquired by shining a {sup 252}Cf source through the container and measuring the radiation at four detectors stacked vertically on the other side. This measurement gives a gamma and neutron radiation transmission profile of the weapons component, mixed with the radiation production due to the induced fissions in the fissile materials. This information is sufficient to match an "unknown" weapons component signature to a template signature from a reference item when measuring under controlled conditions. Tomography measures the interior of an item by making transmission measurements from all angles around the item, whereas NMIS makes the measurements from a single angle. Figure 1 is a standard example of tomographic reconstruction, the Shepp-Logan human brain phantom. The measured quantity is attenuation so high values (white) are highly attenuating areas.
Date: March 11, 2003
Creator: Mullens, J. A.
Object Type: Report
System: The UNT Digital Library