Search for scalar top quarks in the acoplanar charm jets and missing transverse energy final state in p anti-p collisions at s**(1/2) = 1.96-TeV (open access)

Search for scalar top quarks in the acoplanar charm jets and missing transverse energy final state in p anti-p collisions at s**(1/2) = 1.96-TeV

None
Date: March 1, 2008
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
Object Type: Article
System: The UNT Digital Library
Characterization of shape memory alloys for safety mechanisms. (open access)

Characterization of shape memory alloys for safety mechanisms.

Shape memory alloys (SMAs) are metals that exhibit large recoverable strains and exert large forces with tremendous energy densities. The behavior of SMAs is thermomechanically coupled. Their response to temperature is sensitive to their loading condition and their response to loading is sensitive to their thermal condition. This coupled behavior is not to be circumvented, but to be confronted and understood, since it is what manifests SMA's superior clamping performance. To reasonably characterize the coupled behavior of SMA clamping rings used in safety mechanisms, we conduct a series of experiments on SMA samples. The results of the tests will allow increased fidelity in modeling and failure analysis of parts.
Date: March 1, 2008
Creator: McLaughlin, Jarred T.; Buchheit, Thomas Edward & Massad, Jordan Elias
Object Type: Report
System: The UNT Digital Library
Next Generation Nuclear Plant Phenomena Identification and Ranking Tables (PIRTs) Volume 5: Graphite PIRTs (open access)

Next Generation Nuclear Plant Phenomena Identification and Ranking Tables (PIRTs) Volume 5: Graphite PIRTs

Here we report the outcome of the application of the Nuclear Regulatory Commission (NRC) Phenomena Identification and Ranking Table (PIRT) process to the issue of nuclear-grade graphite for the moderator and structural components of a next generation nuclear plant (NGNP), considering both routine (normal operation) and postulated accident conditions for the NGNP. The NGNP is assumed to be a modular high-temperature gas-cooled reactor (HTGR), either a gas-turbine modular helium reactor (GTMHR) version [a prismatic-core modular reactor (PMR)] or a pebble-bed modular reactor (PBMR) version [a pebble bed reactor (PBR)] design, with either a direct- or indirect-cycle gas turbine (Brayton cycle) system for electric power production, and an indirect-cycle component for hydrogen production. NGNP design options with a high-pressure steam generator (Rankine cycle) in the primary loop are not considered in this PIRT. This graphite PIRT was conducted in parallel with four other NRC PIRT activities, taking advantage of the relationships and overlaps in subject matter. The graphite PIRT panel identified numerous phenomena, five of which were ranked high importance-low knowledge. A further nine were ranked with high importance and medium knowledge rank. Two phenomena were ranked with medium importance and low knowledge, and a further 14 were ranked medium importance …
Date: March 1, 2008
Creator: Burchell, Timothy D; Bratton, Rob; Marsden, Barry; Srinivasan, Makuteswara; Penfield, Scott; Mitchell, Mark et al.
Object Type: Report
System: The UNT Digital Library
Mechanism of Phosphorus Removal from Hanford Tank Sludge by Caustic Leaching (open access)

Mechanism of Phosphorus Removal from Hanford Tank Sludge by Caustic Leaching

Two experiments were conducted to explore the mechanism by which phosphorus is removed from Hanford tank sludge by caustic leaching. In the first experiment, a series of phosphate salts were treated with 3 M NaOH under conditions prototypic of the actual leaching process to be performed in the Waste Treatment and Immobilization Plant (WTP). The phosphates used were aluminum phosphate, bismuth phosphate, chromium(III) phosphate, and -tri-calcium phosphate; all of these phases have previously been determined to exist in Hanford tank sludge. The leachate solution was sampled at selected time intervals and analyzed for the specific metal ion involved (Al, Bi, Ca, or Cr) and for P (total and as phosphate). The solids remaining after completion of the caustic leaching step were analyzed to determine the reaction product. In the second experiment, the dependence of P removal from bismuth phosphate was examined as a function of the hydroxide ion concentration. It was anticipated that a plot of log[phosphate] versus log[hydroxide] would provide insight into the phosphorus-removal mechanism. This report describes the test activities outlined in Section 6.3.2.1, Preliminary Investigation of Phosphate Dissolution, in Test Plan TP-RPP-WTP-467, Rev.1. The objectives, success criteria, and test conditions of Section 6.3.2.1 are summarized here.
Date: March 5, 2008
Creator: Lumetta, Gregg J.
Object Type: Report
System: The UNT Digital Library
TRANSITION STATE FOR THE GAS-PHASE REACTION OF URANIUM HEXAFLUORIDE WITH WATER (open access)

TRANSITION STATE FOR THE GAS-PHASE REACTION OF URANIUM HEXAFLUORIDE WITH WATER

Density Functional Theory and small-core, relativistic pseudopotentials were used to look for symmetric and asymmetric transitions states of the gas-phase hydrolysis reaction of uranium hexafluoride, UF{sub 6}, with water. At the B3LYP/6-31G(d,p)/SDD level, an asymmetric transition state leading to the formation of a uranium hydroxyl fluoride, U(OH)F{sub 5}, and hydrogen fluoride was found with an energy barrier of +77.3 kJ/mol and an enthalpy of reaction of +63.0 kJ/mol (both including zero-point energy corrections). Addition of diffuse functions to all atoms except uranium led to only minor changes in the structure and relative energies of the reacting complex and transition state. However, a significant change in the product complex structure was found, significantly reducing the enthalpy of reaction to +31.9 kJ/mol. Similar structures and values were found for PBE0 and MP2 calculations with this larger basis set, supporting the B3LYP results. No symmetric transition state leading to the direct formation of uranium oxide tetrafluoride, UOF{sub 4}, was found, indicating that the reaction under ambient conditions likely includes several more steps than the mechanisms commonly mentioned. The transition state presented here appears to be the first published transition state for the important gas-phase reaction of UF{sub 6} with water.
Date: March 18, 2008
Creator: Garrison, S & James Becnel, J
Object Type: Article
System: The UNT Digital Library
Determination of the Evaporation Coefficient of D2O (open access)

Determination of the Evaporation Coefficient of D2O

The evaporation rate of D{sub 2}O has been determined by Raman thermometry of a droplet train (12-15 {micro}m diameter) injected into vacuum ({approx}10{sup -5} torr). The cooling rate measured as a function of time in vacuum was fit to a model that accounts for temperature gradients between the surface and the core of the droplets, yielding an evaporation coefficient ({gamma}{sub e}) of 0.57 {+-} 0.06. This is nearly identical to that found for H{sub 2}O (0.62 {+-} 0.09) using the same experimental method and model, and indicates the existence of a kinetic barrier to evaporation. The application of a recently developed transition state theory (TST) model suggests that the kinetic barrier is due to librational and hindered translational motions at the liquid surface, and that the lack of an isotope effect is due to competing energetic and entropic factors. The implications of these results for cloud and aerosol particles in the atmosphere are discussed.
Date: March 26, 2008
Creator: Drisdell, Walter S.; Cappa, Christopher D.; Smith, Jared D.; Saykally, Richard J. & Cohen, Ronald C.
Object Type: Article
System: The UNT Digital Library
Cleanup Verification Package for the 118-F-8:4 Fuel Storage Basin West Side Adjacent and Side Slope Soils (open access)

Cleanup Verification Package for the 118-F-8:4 Fuel Storage Basin West Side Adjacent and Side Slope Soils

This cleanup verification package documents completion of remedial action, sampling activities, and compliance with cleanup criteria for the 118-F-8:4 Fuel Storage Basin West Side Adjacent and Side Slope Soils. The rectangular-shaped concrete basin on the south side of the 105-F Reactor building served as an underwater collection, storage, and transfer facility for irradiated fuel elements discharged from the reactor.
Date: March 18, 2008
Creator: Habel, L. D.
Object Type: Report
System: The UNT Digital Library
Development of a fracture network: a block and springs model (open access)

Development of a fracture network: a block and springs model

Since flow in fractured reservoirs is significantly enhanced by clusters of inter-connecting fractures, it's important to understand their inter-connectedness. In these fractured reservoirs, one often finds two sets of fractures due to two separate geologic events. We have developed a blocks and springs model to study how the second generation fractures intersect the first generation of. We find a percolation-like transition where the cluster size grows with increasing strain leading to system-spanning fractal clusters. Increasing the thickness of the layer being fractured leads to sparser system-spanning fracture clusters with smaller fractal dimension. We have studied how the thickness of the layer affects the fractal character of the fracture clusters as well as their number distribution, and the correlations within the large fracture cluster.
Date: March 1, 2008
Creator: Ferer, M. V.; Jozwick, A. & Smith, D. H.
Object Type: Article
System: The UNT Digital Library
Gluon scattering in N=4 super-Yang-Mills theory fromweak to strong coupling (open access)

Gluon scattering in N=4 super-Yang-Mills theory fromweak to strong coupling

I describe some recent developments in the understanding of gluon scattering amplitudes in N = 4 super-Yang-Mills theory in the large-N{sub c} limit. These amplitudes can be computed to high orders in the weak coupling expansion, and also now at strong coupling using the AdS/CFT correspondence. They hold the promise of being solvable to all orders in the gauge coupling, with the help of techniques based on integrability. They are intimately related to expectation values for polygonal Wilson loops composed of light-like segments.
Date: March 25, 2008
Creator: Dixon, Lance J.
Object Type: Article
System: The UNT Digital Library
Evaluation of Homogeneous Options: Effects of Minor Actinide Exclusion from Single and Double Tier Recycle in Sodium Fast Reactors (open access)

Evaluation of Homogeneous Options: Effects of Minor Actinide Exclusion from Single and Double Tier Recycle in Sodium Fast Reactors

The Systems Analysis Campaign under the Global Nuclear Energy Partnership (GNEP) has requested the fuel cycle analysis group at the Idaho National Laboratory (INL) to analyze and provide isotopic data for four scenarios in which different strategies for Minor Actinides (MA) management are investigated. A 1000 MWth commercial-scale Sodium Fast Reactor (SFR) design was selected as the baseline in this scenario study. Two transuranic (TRU) conversion ratios, defined as the ratio of the amount of TRU produced over the TRU destroyed in the reactor core, along with different fuel-types were investigated.
Date: March 1, 2008
Creator: Ferrer, R. M.; Bays, S. & Pope, M.
Object Type: Report
System: The UNT Digital Library
Unraveling duality violations in hadronic tau decays (open access)

Unraveling duality violations in hadronic tau decays

There are some indications from recent determinations of the strong coupling constant alpha_s and the gluon condensate that the Operator Product Expansion may not be accurate enough to describe non-perturbative effects in hadronic tau decays. This breakdown of the Operator Product Expansion is usually referred to as being due to"Duality Violations." With the help of a physically motivated model, we investigate these duality violations. Based on this model, we argue how they may introduce a non-negligible systematic error in the current analysis, which employs finite-energy sum rules with pinched weights. In particular, this systematic effect might affect the precision determination of alpha_s from tau decays. With a view to a possible future application to real data, we present an alternative method for determining the OPE coefficients that might help estimating, and possibly even reducing, this systematic error.
Date: March 3, 2008
Creator: Cata, Oscar; Cata, Oscar; Golterman, Maarten & Peris, Santiago
Object Type: Article
System: The UNT Digital Library
Criteria for Determination of Material Control and Accountability System Effectiveness (open access)

Criteria for Determination of Material Control and Accountability System Effectiveness

The Nevada Test Site (NTS) is a test bed for implementation of the Safeguards First Principles Initiative (SFPI), a risk-based approach to Material Control & Accountability (MC&A) requirements. The Comprehensive Assessment of Safeguards Strategies (COMPASS) model is used to determine the effectiveness of MC&A systems under SFPI. Under this model, MC&A is divided into nine primary elements. Each element is divided into sub-elements. Then each sub-element is assigned two values, effectiveness and contribution, that are used to calculate the rating. Effectiveness is a measure of subelement implementation and how well it meets requirements. Contribution is a relative measure of the importance, and functions as a weighting factor. The COMPASS model provides the methodology for calculation of sub-element and element ratings, but not the actual criteria. Each site must develop its own criteria. For the rating to be meaningful, the effectiveness criteria must be objective and based on explicit, measurable criteria. Contribution (weights) must reflect the importance within the MC&A program. This paper details the NTS approach to system effectiveness and contribution values, and will cover the following: the basis for the ratings, an explanation of the contribution “weights,” and the objective, performance based effectiveness criteria. Finally, the evaluation process will …
Date: March 1, 2008
Creator: Wright, John
Object Type: Article
System: The UNT Digital Library
SURFACE GEOPHYSICAL EXPLORATION OF TX AND TY TANK FARMS AT THE HANFORD SITE RESULTS OF BACKGROUND CHARACTERIZATION WITH MAGNETICS AND ELECTROMAGNETIC (open access)

SURFACE GEOPHYSICAL EXPLORATION OF TX AND TY TANK FARMS AT THE HANFORD SITE RESULTS OF BACKGROUND CHARACTERIZATION WITH MAGNETICS AND ELECTROMAGNETIC

None
Date: March 19, 2008
Creator: DA, MYERS; D, RUCKER; M, LEBITT; B, CUBBAGE & HENDERSON
Object Type: Report
System: The UNT Digital Library
An Integrated Assessment of Geochemical and Community Structure Determinants of Metal Reduction Rates in Subsurface Sediments (open access)

An Integrated Assessment of Geochemical and Community Structure Determinants of Metal Reduction Rates in Subsurface Sediments

This project represented a joint effort between Oak Ridge National Laboratory (ORNL), the University of Tennessee (UT), and Florida State University (FSU). ORNL served as the lead in-stitution with Dr. A.V. Palumbo responsible for project coordination, integration, and deliver-ables. In situ uranium bioremediation is focused on biostimulating indigenous microorganisms through a combination of pH neutralization and the addition of large amounts of electron donor. Successful biostimulation of U(VI) reduction has been demonstrated in the field and in the laboratory. However, little data is available on the dynamics of microbial populations capable of U(VI) reduction, and the differences in the microbial community dynamics between proposed electron donors have not been explored. In order to elucidate the potential mechanisms of U(VI) reduction for optimization of bioremediation strategies, structure-function relationships of microbial populations were investigated in microcosms of subsurface materials cocontaminated with radionuclides and nitrate from the Oak Ridge Field Research Center (ORFRC), Oak Ridge, Tennessee.
Date: March 24, 2008
Creator: Kostka, Joel E.
Object Type: Report
System: The UNT Digital Library
Hydrogen Technologies Group (open access)

Hydrogen Technologies Group

The Hydrogen Technologies Group at the National Renewable Energy Laboratory advances the Hydrogen Technologies and Systems Center's mission by researching a variety of hydrogen technologies.
Date: March 1, 2008
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Project Closeout: Guidance for Final Evaluation of Building America Communities (open access)

Project Closeout: Guidance for Final Evaluation of Building America Communities

This report presents guidelines for Project Closeout. It is used to determine whether the Building America program is successfully facilitating improved design and practices to achieve energy savings goals in production homes. Its objective is to use energy simulations, targeted utility bill analysis, and feedback from project stakeholders to evaluate the performance of occupied BA communities.
Date: March 1, 2008
Creator: Norton, P.; Burch, J. & Hendron, B.
Object Type: Report
System: The UNT Digital Library
Least Squares Magnetic-Field Optimization for Portable Nuclear Magnetic Resonance Magnet Design (open access)

Least Squares Magnetic-Field Optimization for Portable Nuclear Magnetic Resonance Magnet Design

Single-sided and mobile nuclear magnetic resonance (NMR) sensors have the advantages of portability, low cost, and low power consumption compared to conventional high-field NMR and magnetic resonance imaging (MRI) systems. We present fast, flexible, and easy-to-implement target field algorithms for mobile NMR and MRI magnet design. The optimization finds a global optimum ina cost function that minimizes the error in the target magnetic field in the sense of least squares. When the technique is tested on a ring array of permanent-magnet elements, the solution matches the classical dipole Halbach solution. For a single-sided handheld NMR sensor, the algorithm yields a 640 G field homogeneous to 16 100 ppm across a 1.9 cc volume located 1.5 cm above the top of the magnets and homogeneous to 32 200 ppm over a 7.6 cc volume. This regime is adequate for MRI applications. We demonstrate that the homogeneous region can be continuously moved away from the sensor by rotating magnet rod elements, opening the way for NMR sensors with adjustable"sensitive volumes."
Date: March 27, 2008
Creator: Paulsen, Jeffrey L; Franck, John; Demas, Vasiliki & Bouchard, Louis-S.
Object Type: Article
System: The UNT Digital Library
Sustaining knowledge in the neutron generator community and benchmarking study. (open access)

Sustaining knowledge in the neutron generator community and benchmarking study.

In 2004, the Responsive Neutron Generator Product Deployment department embarked upon a partnership with the Systems Engineering and Analysis knowledge management (KM) team to develop knowledge management systems for the neutron generator (NG) community. This partnership continues today. The most recent challenge was to improve the current KM system (KMS) development approach by identifying a process that will allow staff members to capture knowledge as they learn it. This 'as-you-go' approach will lead to a sustainable KM process for the NG community. This paper presents a historical overview of NG KMSs, as well as research conducted to move toward sustainable KM.
Date: March 1, 2008
Creator: Barrentine, Tameka C.; Kennedy, Bryan C.; Saba, Anthony W.; Turgeon, Jennifer L.; Schneider, Julia Teresa; Stubblefield, William Anthony et al.
Object Type: Report
System: The UNT Digital Library
Beam Dynamics Studies for the SPARC Project (open access)

Beam Dynamics Studies for the SPARC Project

The aim of the SPARC project, is to promote an R&D activity oriented to the development of a high brightness photoinjector to drive SASE-FEL experiments. We discuss in this paper the status of the beam dynamics simulation activities.
Date: March 17, 2008
Creator: Ferrario, M.; Biagini, Maria E.; Boscolo, M.; Fusco, V.; Guiducci, S.; Migliorati, M. et al.
Object Type: Article
System: The UNT Digital Library
Argonne National Laboratory Summary Site Environmental Report for Calendar Year 2006. (open access)

Argonne National Laboratory Summary Site Environmental Report for Calendar Year 2006.

This booklet is designed to inform the public about what Argonne National Laboratory is doing to monitor its environment and to protect its employees and neighbors from any adverse environmental impacts from Argonne research. The Downers Grove South Biology II class was selected to write this booklet, which summarizes Argonne's environmental monitoring programs for 2006. Writing this booklet also satisfies the Illinois State Education Standard, which requires that students need to know and apply scientific concepts to graduate from high school. This project not only provides information to the public, it will help students become better learners. The Biology II class was assigned to condense Argonne's 300-page, highly technical Site Environmental Report into a 16-page plain-English booklet. The site assessment relates to the class because the primary focus of the Biology II class is ecology and the environment. Students developed better learning skills by working together cooperatively, writing and researching more effectively. Students used the Argonne Site Environmental Report, the Internet, text books and information from Argonne scientists to help with their research on their topics. The topics covered in this booklet are the history of Argonne, groundwater, habitat management, air quality, Argonne research, Argonne's environmental non-radiological program, radiation, and …
Date: March 27, 2008
Creator: Golchert, N. W. & Oversight, ESH /QA
Object Type: Report
System: The UNT Digital Library
Biosafety Practices and Emergency Response at the Idaho National Laboratory and Los Alamos National Laboratory (open access)

Biosafety Practices and Emergency Response at the Idaho National Laboratory and Los Alamos National Laboratory

Strict federal regulations govern the possession, use, and transfer of pathogens and toxins with potential to cause harm to the public, either through accidental or deliberate means. Laboratories registered through either the Centers for Disease Control and Prevention (CDC), the U.S. Dept. of Agriculture (USDA), or both, must prepare biosafety, security, and incident response plans, conduct drills or exercises on an annual basis, and update plans accordingly. At the Idaho National Laboratory (INL), biosafety, laboratory, and emergency management staff have been working together for 2 years to satisfy federal and DOE/NNSA requirements. This has been done through the establishment of plans, training, tabletop and walk-through exercises and drills, and coordination with local and regional emergency response personnel. Responding to the release of infectious agents or toxins is challenging, but through familiarization with the nature of the hazardous biological substances or organisms, and integration with laboratory-wide emergency response procedures, credible scenarios are being used to evaluate our ability to protect workers, the public, and the environment from agents we must work with to provide for national biodefense.
Date: March 1, 2008
Creator: Roberto, Frank F. & Matz, Dina M.
Object Type: Article
System: The UNT Digital Library
Suspension Hydrogen Reduction of Iron Oxide Concentrates (open access)

Suspension Hydrogen Reduction of Iron Oxide Concentrates

The objective of the project is to develop a new ironmaking technology based on hydrogen and fine iron oxide concentrates in a suspension reduction process. The ultimate objective of the new technology is to replace the blast furnace and to drastically reduce CO2 emissions in the steel industry. The goals of this phase of development are; the performance of detailed material and energy balances, thermochemical and equilibrium calculations for sulfur and phosphorus impurities, the determination of the complete kinetics of hydrogen reduction and bench-scale testing of the suspension reduction process using a large laboratory flash reactor.
Date: March 31, 2008
Creator: Sohn, H. Y.
Object Type: Report
System: The UNT Digital Library
Using Perturbed QR Factorizations To Solve Linear Least-Squares Problems (open access)

Using Perturbed QR Factorizations To Solve Linear Least-Squares Problems

We propose and analyze a new tool to help solve sparse linear least-squares problems min{sub x} {parallel}Ax-b{parallel}{sub 2}. Our method is based on a sparse QR factorization of a low-rank perturbation {cflx A} of A. More precisely, we show that the R factor of {cflx A} is an effective preconditioner for the least-squares problem min{sub x} {parallel}Ax-b{parallel}{sub 2}, when solved using LSQR. We propose applications for the new technique. When A is rank deficient we can add rows to ensure that the preconditioner is well-conditioned without column pivoting. When A is sparse except for a few dense rows we can drop these dense rows from A to obtain {cflx A}. Another application is solving an updated or downdated problem. If R is a good preconditioner for the original problem A, it is a good preconditioner for the updated/downdated problem {cflx A}. We can also solve what-if scenarios, where we want to find the solution if a column of the original matrix is changed/removed. We present a spectral theory that analyzes the generalized spectrum of the pencil (A*A,R*R) and analyze the applications.
Date: March 21, 2008
Creator: Avron, Haim; Ng, Esmond G. & Toledo, Sivan
Object Type: Article
System: The UNT Digital Library
SHIELDING ANALYSIS FOR X-RAY SOURCES GENERATED IN TARGET CHAMBER OF THE NATIONAL IGNITION FACILITY (open access)

SHIELDING ANALYSIS FOR X-RAY SOURCES GENERATED IN TARGET CHAMBER OF THE NATIONAL IGNITION FACILITY

Prompt doses from x-rays generated as result of laser beam interaction with target material are calculated at different locations inside the National Ignition Facility (NIF). The maximum dose outside a Target Chamber diagnostic port is {approx} 1 rem for a shot utilizing the 192 laser beams and 1.8 MJ of laser energy. The dose during a single bundle shot (8 laser beams) drops to {approx} 40 mrem. Doses calculated outside the Target Bay doors and inside the Switchyards (except for the 17 ft.-6 in. level) range from a fraction of mrem to about 11 mrem for 192 beams, and scales down proportionally with smaller number of beams. At the 17ft.-6 in. level, two diagnostic ports are directly facing two of the Target Bay doors and the maximum doses outside the doors are 51 and 15.5 mrem, respectively. Shielding each of the two Target Bay doors with 1/4 in. Pb reduces the dose by factor of fifty. One or two bundle shots (8 to 16 laser beams) present a small hazard to personnel in the Switchyards.
Date: March 27, 2008
Creator: Khater, H Y; Brereton, S J & Singh, M S
Object Type: Article
System: The UNT Digital Library