New ZnO-Based Regenerable Sulfur Sorbents for Fluid-Bed/Transport Reactor Applications (open access)

New ZnO-Based Regenerable Sulfur Sorbents for Fluid-Bed/Transport Reactor Applications

The overall objective of the ongoing sorbent development work at GTI is the advancement to the demonstration stage of a promising ZnO-TiO2 sulfur sorbent that has been developed under DCCA/ICCI and DOE/NETL sponsorship. This regenerable sorbent has been shown to possess an exceptional combination of excellent chemical reactivity, high effective capacity for sulfur absorption, high resistance to attrition, and regenerability at temperatures lower than required by typical zinc titanates.
Date: September 19, 2002
Creator: Slimane, R.B.; Lau, F.S.; Abbasian, J. & Ho, K.H.
Object Type: Article
System: The UNT Digital Library
Roller Burnishing - A Cold Working Tool to Reduce Weld Induced Residual Stress (open access)

Roller Burnishing - A Cold Working Tool to Reduce Weld Induced Residual Stress

The possibility of stress corrosion cracking (SCC) in regions of tensile residual stress introduced by weld deposited material has been a concern where environmental effects can reduce component life. Roller burnishing, a form of mechanical cold-working, has been considered as a means of providing for residual stress state improvements. This paper provides a computational evaluation of the roller burnishing process to address the permanent deformation needed to introduce a desirable residual stress state. The analysis uses a series of incrementally applied pressure loadings and finite element methodology to simulate the behavior of a roller burnishing tool. Various magnitudes of applied pressure loadings coupled with different size plates and boundary conditions are examined to assess the degree and depth of the residual compressive stress state after cold working. Both kinematic and isotropic hardening laws are evaluated.
Date: February 19, 2002
Creator: Martin, John
Object Type: Report
System: The UNT Digital Library
Catalysis of Reduction and Oxidation Reactions for Application in Gas Particle Filters (open access)

Catalysis of Reduction and Oxidation Reactions for Application in Gas Particle Filters

The present study is a first part of an investigation addressing the simultaneous occurrence of oxidation and reduction reactions in catalytic filters. It has the objectives (a) to assess the state of knowledge regarding suitable (types of) catalysts for reduction and oxidation, (b) to collect and analyze published information about reaction rates of both NOx reduction and VOC oxidation, and (c) to adjust a lab-scale screening method to the requirements of an activity test with various oxidation/reduction catalysts.
Date: September 19, 2002
Creator: Udron, L. & Turek, T.
Object Type: Article
System: The UNT Digital Library
Simultaneous Removal of Particulates and NOx Using Catalyst Impregnated Fibrous Ceramic Filters (open access)

Simultaneous Removal of Particulates and NOx Using Catalyst Impregnated Fibrous Ceramic Filters

The research is focused on the development and commercialization of high efficiency, cost effective air pollution control system, which can replace in part air pollution control devices currently in use. In many industrial processes, hot exhaust gases are cooled down to recover heat and to remove air pollutants in exhaust gases. Conventional air pollution control devices such as bag filters, E.P. and adsorption towers withstand operating temperatures up to 300 C. Also, reheating is sometimes necessary to meet temperature windows for S.C.R. Since Oxidation reactions of acid gases such as SO{sub 2}, and HCl with lime are enhanced at high temperatures, catalyst impregnated ceramic filters can be candidate for efficient and cost effective air pollution control devices. As shown on Fig. 1., catalytic ceramic filters remove particulates on exterior surface of filters and acid gases are oxidized to salts reacting with limes injected in upstream ducts. Oxidation reactions are enhanced in the cake formed on exterior of filters. Finally, injected reducing gas such as NH{sub 3} react with NOx to form N{sub 2} and H{sub 2}O interior of filters in particulate-free environment. Operation and maintenance technology is similar to conventional bag filters except that systems are exposed to relatively high …
Date: September 19, 2002
Creator: Choi, J. I.; Mun, S. H.; Kim, S. T.; Hong, M. S. & Lee, J. C.
Object Type: Article
System: The UNT Digital Library
Characterization of Field-Exposed Iron Aluminide Hot Gas Filters (open access)

Characterization of Field-Exposed Iron Aluminide Hot Gas Filters

The use of a power turbine fired with coal-derived synthesis gas will require some form of gas cleaning in order to protect turbine and downstream components from degradation by erosion, corrosion, or deposition. Hot-gas filtration is one form of cleaning that offers the ability to remove particles from the gases produced by gasification processes without having to substantially cool and, possibly, reheat them before their introduction into the turbine. This technology depends critically on materials durability and reliability, which have been the subject of study for a number of years (see, for example, Alvin 1997, Nieminen et al. 1996, Oakey et al. 1997, Quick and Weber 1995, Tortorelli, et al. 1999).
Date: September 19, 2002
Creator: McKamey, Claudette G.; McCleary, David; Tortorelli, Peter F.; Sawyer, John; Lara-Curzio, Edgar & Judkins, Roddie R.
Object Type: Article
System: The UNT Digital Library
Electron-cloud simulation results for the SPS and recent results for the LHC (open access)

Electron-cloud simulation results for the SPS and recent results for the LHC

We present an update of computer simulation results for some features of the electron cloud at the Large Hadron Collider (LHC) and recent simulation results for the Super Proton Synchrotron (SPS). We focus on the sensitivity of the power deposition on the LHC beam screen to the emitted electron spectrum, which we study by means of a refined secondary electron (SE) emission model recently included in our simulation code.
Date: June 19, 2002
Creator: Furman, M. A. & Pivi, M. T. F.
Object Type: Article
System: The UNT Digital Library
The new cosmology (open access)

The new cosmology

Over the past three years we have determined the basic features of our Universe. It is spatially flat; accelerating; comprised of 1/3 a new form of matter, 2/3 a new form of energy, with some ordinary matter and a dash of massive neutrinos; and it apparently began from a great burst of expansion during which quantum noise was stretched to astrophysical size seeding cosmic structure. This ''New Cosmology'' greatly extends the highly successful hot big-bang model. Now we have to make sense of it. What is the dark matter particle? What is the nature of the dark energy? Why this mixture? How did the matter, antimatter asymmetry arise? What is the underlying cause of inflation (if it indeed occurred)?
Date: November 19, 2002
Creator: Turner, Michael S.
Object Type: Article
System: The UNT Digital Library
Development of the LBNL positron emission mammography camera (open access)

Development of the LBNL positron emission mammography camera

We present the construction status of the LBNL Positron Emission Mammography (PEM) camera, which utilizes a PET detector module with depth of interaction measurement consisting of 64 LSO crystals (3x3x30 mm3) coupled on one end to a single photomultiplier tube (PMT) and on the opposite end to a 64 pixel array of silicon photodiodes (PDs). The PMT provides an accurate timing pulse, the PDs identify the crystal of interaction, the sum provides a total energy signal, and the PD/(PD+PMT) ratio determines the depth of interaction. We have completed construction of all 42 PEM detector modules. All data acquisition electronics have been completed, fully tested and loaded onto the gantry. We have demonstrated that all functions of the custom IC work using the production rigid-flex boards and data acquisition system. Preliminary detector module characterization and coincidence data have been taken using the production system, including initial images.
Date: December 19, 2002
Creator: Huber, Jennifer S.; Choong, Woon-Seng; Wang, Jimmy; Maltz, Jonathon S.; Qi, Jinyi; Mandelli, Emanuele et al.
Object Type: Article
System: The UNT Digital Library
Simulations of electron cloud build-up and saturation in the APS (open access)

Simulations of electron cloud build-up and saturation in the APS

In studies with positron beams in the Advanced Photon Source, a dramatic amplification was observed in the electron cloud for certain bunch current and bunch spacings. In modeling presented previously, we found qualitative agreement with the observed beam-induced multipacting condition, provided reasonable values were chosen for the secondary electron yield parameters, including the energy distribution. In this paper, we model and discuss the build-up and saturation process observed over long bunch trains at the resonance condition. Understanding this saturation mechanism in more detail may have implications for predicting electron cloud amplification, multipacting, and instabilities in future rings.
Date: June 19, 2002
Creator: Harkay, K. C.; Rosenberg, R. A.; Furman, M. A. & Pivi, M.
Object Type: Article
System: The UNT Digital Library
Enhancing the Atomic-Level Understanding of co2 Mineral Sequestration Mechanisms via Advanced Computational Modeling (open access)

Enhancing the Atomic-Level Understanding of co2 Mineral Sequestration Mechanisms via Advanced Computational Modeling

Fossil fuels currently provide 85% of the world's energy needs, with the majority coming from coal, due to its low cost, wide availability, and high energy content. The extensive use of coalfired power assumes that the resulting CO{sub 2} emissions can be vented to the atmosphere. However, exponentially increasing atmospheric CO{sub 2} levels have brought this assumption under critical review. Over the last decade, this discussion has evolved from whether exponentially increasing anthropogenic CO{sub 2} emissions will adversely affect the global environment, to the timing and magnitude of their impact. A variety of sequestration technologies are being explored to mitigate CO{sub 2} emissions. These technologies must be both environmentally benign and economically viable. Mineral carbonation is an attractive candidate technology as it disposes of CO{sub 2} as geologically stable, environmentally benign mineral carbonates, clearly satisfying the first criteria. The primary challenge for mineral carbonation is cost-competitive process development. CO{sub 2} mineral sequestration--the conversion of stationary-source CO{sub 2} emissions into mineral carbonates (e.g., magnesium and calcium carbonate, MgCO{sub 3} and CaCO{sub 3})--has recently emerged as one of the most promising sequestration options, providing permanent CO{sub 2} disposal, rather than storage. In this approach a magnesium-bearing feedstock mineral (typically serpentine or olivine; …
Date: December 19, 2002
Creator: Chizmeshya, A. V. G.
Object Type: Report
System: The UNT Digital Library
Scattering in a magnetic field (open access)

Scattering in a magnetic field

The fixed target program at Fermilab has come to an end. New projects are in the planning stage. Among them is a muon storage ring. Up to the present, all storage rings in high-energy physics have carried stable particles, namely the electron and proton and their antiparticles. The muon is unstable and decays with a mean lifetime of 2.0 x 10{sup -6} sec. Two types of cooling have been used in the past. One is stochastic cooling where an electrode is used to detect the positions of the particles and send a signal to another position across the ring. Through successive applications of this technique, the phase space is ultimately greatly reduced and beams can be made to collide with a useful event rate. The second type of cooling is electron cooling. Here protons and electrons are made to travel together for a short distance. Equipartition causes transfer of transverse energy of the protons to that of the electrons. Neither of these methods is fast enough to allow acceleration of a sufficient number of muons up to maximum energy before they decay. A new method known as ionization cooling has been proposed.[1] The muons are cooled by passing them through …
Date: August 19, 2002
Creator: Carey, David C.
Object Type: Article
System: The UNT Digital Library
Condition for production of circulating proton beam with intensity greater than space charge limit. (open access)

Condition for production of circulating proton beam with intensity greater than space charge limit.

Transverse e-p instability in proton rings could be damped by increasing the beam density and the rate of secondary particles production above the threshold level, with the corresponding decrease of unstable wavelength {lambda} below the transverse beam size h (increase of beam density n{sub b} and ion density n{sub i} above the threshold level: n{sub b} + n{sub i} > {beta}{sup 2}/(r{sub e} h{sup 2}), where r{sub e} = e{sup 2}/mc{sup 2}). Such island of stability can be reached by a fast charge-exchange injection without painting and enhanced generation of secondary plasma, which was demonstrated in a small scale Proton Storage Ring (PSR) at the Institute of Nuclear Physics, Novosibirsk, Russia. With successful damping of e-p instability, the intensity of circulating proton beam, with a space charge neutralization was increased up to 6 times above a space charge limit. Corresponding tune shift without space charge neutralization should be up to {Delta}v=0.85 x 6 (in the ring with v = 0.85). In this paper, they review experimental observations of transverse instability of proton beams in various rings. they also discuss methods which can be used to damp the instability. Such experimental data could be useful for verification of computer simulation tools …
Date: November 19, 2002
Creator: Dudnikov, Vadim
Object Type: Article
System: The UNT Digital Library
Global and Regional Ecosystem Modeling: Databases of Model Drivers and Validation Measurements (open access)

Global and Regional Ecosystem Modeling: Databases of Model Drivers and Validation Measurements

Understanding global-scale ecosystem responses to changing environmental conditions is important both as a scientific question and as the basis for making policy decisions. The confidence in regional models depends on how well the field data used to develop the model represent the region of interest, how well the environmental model driving variables (e.g., vegetation type, climate, and soils associated with a site used to parameterize ecosystem models) represent the region of interest, and how well regional model predictions agree with observed data for the region. To assess the accuracy of global model forecasts of terrestrial carbon cycling, two Ecosystem Model-Data Intercomparison (EMDI) workshops were held (December 1999 and April 2001). The workshops included 17 biogeochemical, satellite-driven, detailed process, and dynamic vegetation global model types. The approach was to run regional or global versions of the models for sites with net primary productivity (NPP) measurements (i.e., not fine-tuned for specific site conditions) and analyze the model-data differences. Extensive worldwide NPP data were assembled with model driver data, including vegetation, climate, and soils data, to perform the intercomparison. This report describes the compilation of NPP estimates for 2,523 sites and 5,164 0.5{sup o}-grid cells under the Global Primary Production Data Initiative (GPPDI) …
Date: March 19, 2002
Creator: Olson, R.J.
Object Type: Report
System: The UNT Digital Library
Crossflow Filter Check Out Test Report (open access)

Crossflow Filter Check Out Test Report

As part of the reconstitution of 512-S, a functional test of the Crossflow Filter located in the North Cell of Building 512-S was conducted from July 22 through August 14, 2002. This test was performed in two parts. The first part used water as the process feed. The second part used simulant salt solution, simulant sludge, and monosodium titanate (MST) at various solids loadings as the process feed. The test was designed to demonstrate the cross-flow filter's ability to perform solid-liquid separation on the feed stream and to collect relevant operational data. During the chemical runs, four different batch runs were made at increasing weight percent solids loading. Not all of the 512-S systems were in operation, only those essential for the testing of the Crossflow Filter.
Date: December 19, 2002
Creator: Jones, R.T.
Object Type: Report
System: The UNT Digital Library
Analytical Model for Prediction of Plate-Specific Fracture Toughness Properties of ASTM A285 Steel (open access)

Analytical Model for Prediction of Plate-Specific Fracture Toughness Properties of ASTM A285 Steel

A materials test program was developed to measure mechanical properties of A285 carbon steel under conditions relevant to waste storage tanks at the Savannah River Site.
Date: December 19, 2002
Creator: Subramanian, K.H.
Object Type: Article
System: The UNT Digital Library
Addendum to the Composite Analysis for the E-Area Vaults and Saltstone Disposal Facilities (open access)

Addendum to the Composite Analysis for the E-Area Vaults and Saltstone Disposal Facilities

Revision 1 of the Composite Analysis (CA) Addendum has been prepared to respond to the U.S. Department of Energy (DOE) Low-Level Waste Disposal Facilities Federal Review Group review of the CA. This addendum to the composite analysis responds to the conditions of approval. The composite analysis was performed on the two active SRS low-level radioactive waste disposal facilities. The facilities are the Z-Area Saltstone Disposal Facility and the E-Area Vaults Disposal Facility. The analysis calculated potential releases to the environment from all sources of residual radioactive material expected to remain in the General Separations Area (GSA). The GSA is the central part of the Savannah River Site and contains all of the waste disposal facilities, the chemical separation facilities and associated high-level waste storage facilities, as well as numerous other sources of radioactive material.
Date: December 19, 2002
Creator: Cook, J. R.
Object Type: Report
System: The UNT Digital Library
Waste Isolation Pilot Plant Initial Report for PCB Disposal Authorization (40 CFR {section} 761.75[c]) (open access)

Waste Isolation Pilot Plant Initial Report for PCB Disposal Authorization (40 CFR {section} 761.75[c])

This initial report is being submitted pursuant to Title 40 Code of Federal Regulations (CFR) {section} 761.75(c) to request authorization to allow the disposal of transuranic (TRU) wastes containing polychlorinated biphenyls (PCBs) which are duly regulated under the Toxic Substances Control Act (TSCA). Approval of this initial report will not affect the disposal of TRU or TRU mixed wastes that do not contain PCBs. This initial report also demonstrates how the Waste Isolation Pilot Plant (WIPP) meets or exceeds the technical standards for a Chemical Waste Landfill. Approval of this request will allow the U.S. Department of Energy (DOE) to dispose of approximately 88,000 cubic feet (ft3) (2,500 cubic meters [m3]) of TRU wastes containing PCBs subject to regulation under the TSCA. This approval will include only those PCB/TRU wastes, which the TSCA regulations allow for disposal of the PCB component in municipal solid waste facilities or chemical waste landfills (e.g., PCB remediation waste, PC B articles, and bulk PCB product waste). Disposal of TRU waste by the DOE is congressionally mandated in Public Law 102-579 (as amended by the National Defense Authorization Act for Fiscal Year 1997, Pub. L. 104-201, referred to as the WIPP Land Withdrawal Act [LWA]). …
Date: March 19, 2002
Creator: Solutions, Westinghouse TRU
Object Type: Report
System: The UNT Digital Library
Improving Control Room Design and Operations Based on Human Factors Analyses or How Much Human Factors Upgrade Is Enough ? (open access)

Improving Control Room Design and Operations Based on Human Factors Analyses or How Much Human Factors Upgrade Is Enough ?

THE JOSE CABRERA NUCLEAR POWER PLANT IS A ONE LOOP WESTINGHOUSE PRESSURIZED WATER REACTOR. IN THE CONTROL ROOM, THE DISPLAYS AND CONTROLS USED BY OPERATORS FOR THE EMERGENCY OPERATING PROCEDURES ARE DISTRIBUTED ON FRONT AND BACK PANELS. THIS CONFIGURATION CONTRIBUTED TO RISK IN THE PROBABILISTIC SAFETY ASSESSMENT WHERE IMPORTANT OPERATOR ACTIONS ARE REQUIRED. THIS STUDY WAS UNDERTAKEN TO EVALUATE THE IMPACT OF THE DESIGN ON CREW PERFORMANCE AND PLANT SAFETY AND TO DEVELOP DESIGN IMPROVEMENTS.FIVE POTENTIAL EFFECTS WERE IDENTIFIED. THEN NUREG-0711 [1], PROGRAMMATIC, HUMAN FACTORS, ANALYSES WERE CONDUCTED TO SYSTEMATICALLY EVALUATE THE CR-LA YOUT TO DETERMINE IF THERE WAS EVIDENCE OF THE POTENTIAL EFFECTS. THESE ANALYSES INCLUDED OPERATING EXPERIENCE REVIEW, PSA REVIEW, TASK ANALYSES, AND WALKTHROUGH SIMULATIONS. BASED ON THE RESULTS OF THESE ANALYSES, A VARIETY OF CONTROL ROOM MODIFICATIONS WERE IDENTIFIED. FROM THE ALTERNATIVES, A SELECTION WAS MADE THAT PROVIDED A REASONABLEBALANCE BE TWEEN PERFORMANCE, RISK AND ECONOMICS, AND MODIFICATIONS WERE MADE TO THE PLANT.
Date: September 19, 2002
Creator: Higgins, J. C.; Ohara, J. M. & Almeida, P.
Object Type: Article
System: The UNT Digital Library
Dark matter and dark energy: The critical questions (open access)

Dark matter and dark energy: The critical questions

Stars account for only about 0.5% of the content of the Universe; the bulk of the Universe is optically dark. The dark side of the Universe is comprised of: at least 0.1% light neutrinos; 3.5% {+-} 1% baryons; 29% {+-} 4% cold dark matter; and 66% {+-} 6% dark energy. Now that we have characterized the dark side of the Universe, the challenge is to understand it. The critical questions are: (1) What form do the dark baryons take? (2) What is (are) the constituent(s) of the cold dark matter? (3) What is the nature of the mysterious dark energy that is causing the Universe to speed up.
Date: November 19, 2002
Creator: Turner, Michael S.
Object Type: Article
System: The UNT Digital Library
Summary of radiation damage studies on rare earth permanent magnets (open access)

Summary of radiation damage studies on rare earth permanent magnets

With the proposed use of permanent magnets for both the NLC and the VLHC the issue flux loss due to radiation damage needs to be fully understood. There exist many papers on the subject. There are many difficulties in drawing conclusions from all of these data. First there is the difference methods of dosimetry, second different types of magnets and magnetic arrangements, and third different manufacturers of magnet material. This paper provides a summary of the existing literature on the subject.
Date: November 19, 2002
Creator: Volk, J. T.
Object Type: Article
System: The UNT Digital Library
Studies of Ion Exchange Resin Integrity under Flowsheet Extremes: Part II (open access)

Studies of Ion Exchange Resin Integrity under Flowsheet Extremes: Part II

This task addressed four items related to SuperLig(R) 644 ion exchange resin stability under nominal to extreme conditions.
Date: December 19, 2002
Creator: Nash, C.A.
Object Type: Report
System: The UNT Digital Library
Epileptic Seizure Forewarning by Nonlinear Techniques (open access)

Epileptic Seizure Forewarning by Nonlinear Techniques

This report describes work that was performed under a Cooperative Research and Development Agreement (CRADA) between UT-Battelle, LLC (Contractor) and a commercial participant, VIASYS Healthcare Inc. (formerly Nicolet Biomedical, Inc.). The Contractor has patented technology that forewarns of impending epileptic events via scalp electroencephalograph (EEG) data and successfully demonstrated this technology on 20 datasets from the Participant under pre-CRADA effort. This CRADA sought to bridge the gap between the Contractor's existing research-class software and a prototype medical device for subsequent commercialization by the Participant. The objectives of this CRADA were (1) development of a combination of existing computer hardware and Contractor-patented software into a clinical process for warning of impending epileptic events in human patients, and (2) validation of the epilepsy warning methodology. This work modified the ORNL research-class FORTRAN for forewarning to run under a graphical user interface (GUI). The GUI-FORTRAN software subsequently was installed on desktop computers at five epilepsy monitoring units. The forewarning prototypes have run for more than one year without any hardware or software failures. This work also reported extensive analysis of model and EEG datasets to demonstrate the usefulness of the methodology. However, the Participant recently chose to stop work on the CRADA, due …
Date: April 19, 2002
Creator: Hively, L. M.
Object Type: Report
System: The UNT Digital Library
Electron proton two-stream instability at the PSR. (open access)

Electron proton two-stream instability at the PSR.

A strong, fast, transverse instability has long been observed at the Los Alamos Proton Storage Ring (PSR) where it is a limiting factor on peak intensity. Most of the available evidence, based on measurements of the unstable proton beam motion, is consistent with an electron-proton two-stream instability. The need for higher beam intensity at PSR [1] and for future high-intensity, proton drivers has motivated a multi-lab collaboration (LANL, ANL, FNAL, LBNL, BNL, ORNL, and PPPL) to coordinate research on the causes, dynamics and cures for this instability. Important characteristics of the electron cloud were recently measured with retarding field electron analyzers and various collection electrodes. Suppression of the electron cloud formation by TiN coatings has confirmed the importance of secondary emission processes in its generation. New tests of potential controls included dual harmonic rf, damping by higher order multipoles, damping by X,Y coupling and the use of inductive inserts to compensate longitudinal space charge forces. With these controls and higher rf voltage the PSR has accumulated stable beam intensity up to 9.7 {micro}C/pulse (6 x 10{sup 13} protons), which is a 60% increase over the previous maximum.
Date: February 19, 2002
Creator: Macek, R. J.; Browman, A.; Fitzgerald, D.; McCrady, R.; Merrill, F.; Plum, M. et al.
Object Type: Article
System: The UNT Digital Library
Evaluation of Mass Transfer Performance for Caustic-Side Solvent Extraction of Cesium in a Conventional 5-cm Centrifugal Contactor (open access)

Evaluation of Mass Transfer Performance for Caustic-Side Solvent Extraction of Cesium in a Conventional 5-cm Centrifugal Contactor

Tests have been conducted to determine if satisfactory mass transfer performance is achieved using a fully pumping 5-cm centrifugal contactor under conditions present in the Caustic-Side Solvent Extraction (CSSX) process. Tests utilized a commercially available contactor that had been modified by installation of a rotor housing bottom that had straight radial vanes on the process side. As received from the vendor, the housing bottom was equipped with curved (impeller-type) vanes that were intended to promote phase separation by minimizing mixing of influent solutions. Stage efficiencies exceeding 85% were obtained under conditions, present in the extraction section of the CSSX flowsheet. Under CSSX stripping conditions the stage efficiency exceeded 90%. In both cases, the efficiencies obtained exceed the minimum requirement for acceptable transfer of cesium in the CSSX process.
Date: February 19, 2002
Creator: Birdwell, Jr. J.F.
Object Type: Report
System: The UNT Digital Library