A Chemical Kinetic Modeling Study of the Effects of Oxygenated Hydrocarbons on Soot Emissions from Diesel Engines (open access)

A Chemical Kinetic Modeling Study of the Effects of Oxygenated Hydrocarbons on Soot Emissions from Diesel Engines

A detailed chemical kinetic modeling approach is used to examine the phenomenon of suppression of sooting in diesel engines by addition of oxygenated hydrocarbon species to the fuel. This suppression, which has been observed experimentally for a few years, is explained kinetically as a reduction in concentrations of soot precursors present in the hot products of a fuel-rich diesel ignition zone when oxygenates are included. Oxygenates decrease the overall equivalence ratio of the igniting mixture, producing higher ignition temperatures and more radical species to consume more soot precursor species, leading to lower soot production. The kinetic model is also used to show how different oxygenates, ester structures in particular, can have different soot-suppression efficiencies due to differences in molecular structure of the oxygenated species.
Date: November 14, 2005
Creator: Westbrook, C K; Pitz, W J & Curran, H J
Object Type: Article
System: The UNT Digital Library
Is Climate Change Predictable? Really? (open access)

Is Climate Change Predictable? Really?

This project is the first application of a completely different approach to climate modeling, in which new prognostic equations are used to directly compute the evolution of two-point correlations. This project addresses three questions that are critical for the credibility of the science base for climate prediction: (1) What is the variability spectrum at equilibrium? (2) What is the rate of relaxation when subjected to external perturbations? (3) Can variations due to natural processes be distinguished from those due to transient external forces? The technical approach starts with the evolution equation for the probability distribution function and arrives at a prognostic equation for ensemble-mean two-point correlations, bypassing the detailed weather calculation. This work will expand our basic understanding of the theoretical limits of climate prediction and stimulate new experiments to perform with conventional climate models. It will furnish statistical estimates that are inaccessible with conventional climate simulations and likely will raise important new questions about the very nature of climate change and about how (and whether) climate change can be predicted. Solid progress on such issues is vital to the credibility of the science base for climate change research and will provide policymakers evaluating tradeoffs among energy technology options and …
Date: November 14, 2005
Creator: Dannevik, W P & Rotman, D A
Object Type: Report
System: The UNT Digital Library
Study of the Tau- to Pi- Pi+ Pi- Pi0 Nu/Tau And Tau- to Pi- Pi- Pi+ Eta Nu/Tau Decays Using the BaBar Detector (open access)

Study of the Tau- to Pi- Pi+ Pi- Pi0 Nu/Tau And Tau- to Pi- Pi- Pi+ Eta Nu/Tau Decays Using the BaBar Detector

The {tau}{sup -} {yields} {pi}{sup -}{pi}{sup +}{pi}{sup -}{nu}{sub {tau}} and {tau}{sup -} {yields} {pi}{sup -}{pi}{sup -}{pi}{sup +}{eta}{nu}{sub {tau}} decays have been studied with the BABAR detector. Preliminary branching fractions on the two modes are presented. The {tau}{sup -} {yields} {pi}{sup -}{pi}{sup -}{pi}{sup +}{eta}{nu}{sub {tau}} mode is found to have a large contribution from the {tau}{sup -} {yields} {omega}{pi}{sup -}{nu}{sub {tau}} decay. The {tau}{sup -} {yields} {pi}{sup -}{pi}{sup -}{pi}{sup +}{eta}{nu}{sub {tau}} decay is studied using the {eta} {yields} {gamma}{gamma} mode and the {tau}{sup -} f{sub 1}(1285){pi}{sup -}{nu}{sub {tau}} decay is seen to be the primary source of these decays. A 90% confidence level upper limit is placed on the {tau}{sup -} {yields} {eta}{prime}(958){pi}{sup -}{nu}{sub {tau}} decay which proceeds through a second-class current and is expected to be forbidden in the limit of perfect isospin symmetry.
Date: November 14, 2007
Creator: Sobie, Randall
Object Type: Article
System: The UNT Digital Library
Quantitative Microanalysis with high Spatial Resolution: Application of FEG-DTEM XEDS Microanalysis to the Characterization of Complex Microstructures in Irradiated Low Alloy Steet (open access)

Quantitative Microanalysis with high Spatial Resolution: Application of FEG-DTEM XEDS Microanalysis to the Characterization of Complex Microstructures in Irradiated Low Alloy Steet

To assist in the characterization of microstructural changes associated with irradiation damage in low alloy steels, the technique of quantitative x-ray mapping using a field emission gun scanning transmission electron microscope (FEG-STEM) equipped with an x-ray energy Dispersive spectrometer (XEDS) has been employed. Quantitative XEDS microanalyses of the matrix and grain boundaries of irradiated specimens have been compared with previous quantitative analyses obtained using 3D-Atom Probe Field-Ion Microscopy (3D-APFIM). In addition, the FEG-STEM XEDS maps obtained from the irradiated steel have revealed the presence of 2 to 3 nm Ni-enriched 'precipitates' in the matrix, which had previously been detected using 3D-APFIM. These quantitative FEG-STEM XEDS results represent the first direct and independent microchemical corroboration of the 3D-APFIM results showing ultra-fine irradiation-induced hardening features in low alloy steel.
Date: November 14, 2001
Creator: Williams, D.B., Watanabe, M. and Burke, M.G.
Object Type: Report
System: The UNT Digital Library
HESS J1023-575: Non-Thermal Particle Acceleration Associated With the Young Stellar Cluster Westerlund 2 (open access)

HESS J1023-575: Non-Thermal Particle Acceleration Associated With the Young Stellar Cluster Westerlund 2

The results from H.E.S.S. observations towards Westerlund 2 are presented. The detection of very-high-energy gamma-ray emission towards the young stellar cluster Westerlund 2 in the HII complex RCW49 by H.E.S.S. provides ample evidence that particle acceleration to extreme energies is associated with this region. A variety of possible emission scenarios is mentioned, ranging from high-energy gamma-ray production in the colliding wind zone of the massive Wolf-Rayet binary WR 20a, collective wind scenarios, diffusive shock acceleration at the boundaries of wind-blown bubbles in the stellar cluster, and outbreak phenomena from hot stellar winds into the interstellar medium. These scenarios are briefly compared to the characteristics of the associated new VHE gamma-ray source HESS J1023-575, and conclusions on the validity of the respective emission scenarios for high-energy gamma-ray production in the Westerlund 2 system are drawn.
Date: November 14, 2007
Creator: Reimer, O.; /Stanford U., HEPL /KIPAC, Menlo Park; Hinton, J.; U., /Leeds; Hofmann, W.; Hoppe, S. et al.
Object Type: Article
System: The UNT Digital Library
Task Group 7B: Cellular and Molecular Mechanisms of Biological Aging: The Roles of Nature, Nurture and Chance in the Maintenance of Human Healthspan (open access)

Task Group 7B: Cellular and Molecular Mechanisms of Biological Aging: The Roles of Nature, Nurture and Chance in the Maintenance of Human Healthspan

The degree to which an individual organism maintains healthspan and lifespan is a function of complex interactions between genetic inheritance ('nature'), environment, including cultural inheritance (nurture) and stochastic events ('luck' or 'chance'). This task group will focus upon the role of chance because it is so poorly understood and because it appears to be of major importance in the determination of individual variations in healthspan and lifespan within species. The major factor determining variations in healthspan and lifespan between species is genetic inheritance. Broader aspects of cellular and molecular mechanisms of biological aging will also be considered, given their importance for understanding the cellular and molecular basis of successful aging. The task force will consider the cellular and molecular basis for nature, nurture and chance in healthspan and life span determination. On the basis of comparisons between identical and non-identical twins, geneticists have estimated that genes control no more than about a quarter of the inter-individual differences in lifespan (Herskind 1996). Twin studies of very old individuals, however, show substantially greater genetic contributions to Healthspan (McClearn 2004; Reed 2003). The environment clearly plays an important role in the length and the quality of life. Tobacco smoke, for example has the …
Date: November 14, 2007
Creator: Weier, Heinz-Ulrich; Arya, Suresh; Grant, Christine; Miller, Linda; Ono, Santa Jeremy; Patil, Chris et al.
Object Type: Article
System: The UNT Digital Library
Theoretical Treatment of the Thermophysical Properties of Fluids Containing Chain-like Molecules (open access)

Theoretical Treatment of the Thermophysical Properties of Fluids Containing Chain-like Molecules

This research program was designed to enhance our understanding of the behavior of fluids and fluid mixtures containing chain-like molecules. The original objective was to explain and predict the experimentally observed thermophysical properties, including phase equilibria and dynamics, of systems containing long flexible molecules ranging in length from alkanes to polymers. Over the years the objectives were expanded to include the treatment of molecules that were not chain-like. Molecular dynamics and Monte Carlo computer simulations were used to investigate how variations in molecular size, shape and architecture influence the types of phase equilibria, thermodynamic properties, structure and surface interactions that are observed experimentally. The molecular insights and theories resulting from this program could eventually serve as the foundation upon which to build correlations of the properties of fluids that are both directly and indirectly related to the Nation’s energy resources including: petroleum, natural gas, and polymer solutions, melts, blends, and materials.
Date: November 14, 2008
Creator: Hall, Carol K.
Object Type: Report
System: The UNT Digital Library
Science and Technology Review January/February 2008 (open access)

Science and Technology Review January/February 2008

This month's issue has the following articles: (1) The Edward Teller Centennial--Commentary by George H. Miller; (2) Edward Teller's Century: Celebrating the Man and His Vision--Colleagues at the Laboratory remember Edward Teller, cofounder of Lawrence Livermore, adviser to U.S. presidents, and physicist extraordinaire, on the 100th anniversary of his birth; (3) Quark Theory and Today's Supercomputers: It's a Match--Thanks to the power of BlueGene/L, Livermore has become an epicenter for theoretical advances in particle physics; and (4) The Role of Dentin in Tooth Fracture--Studies on tooth dentin show that its mechanical properties degrade with age.
Date: November 14, 2007
Creator: Chinn, D J
Object Type: Report
System: The UNT Digital Library
Accelerating scientific discovery : 2007 annual report. (open access)

Accelerating scientific discovery : 2007 annual report.

As a gateway for scientific discovery, the Argonne Leadership Computing Facility (ALCF) works hand in hand with the world's best computational scientists to advance research in a diverse span of scientific domains, ranging from chemistry, applied mathematics, and materials science to engineering physics and life sciences. Sponsored by the U.S. Department of Energy's (DOE) Office of Science, researchers are using the IBM Blue Gene/L supercomputer at the ALCF to study and explore key scientific problems that underlie important challenges facing our society. For instance, a research team at the University of California-San Diego/ SDSC is studying the molecular basis of Parkinson's disease. The researchers plan to use the knowledge they gain to discover new drugs to treat the disease and to identify risk factors for other diseases that are equally prevalent. Likewise, scientists from Pratt & Whitney are using the Blue Gene to understand the complex processes within aircraft engines. Expanding our understanding of jet engine combustors is the secret to improved fuel efficiency and reduced emissions. Lessons learned from the scientific simulations of jet engine combustors have already led Pratt & Whitney to newer designs with unprecedented reductions in emissions, noise, and cost of ownership. ALCF staff members provide …
Date: November 14, 2008
Creator: Beckman, P.; Dave, P. & Drugan, C.
Object Type: Report
System: The UNT Digital Library
National Childhood Cancer Foundation (open access)

National Childhood Cancer Foundation

The initiative will enable the COG Biopathology Center (Biospecimen Repository), the Molecular Genetics Laboratory and other participating reference laboratories to upload large data sets to the eRDES. The capability streamlines data currency and accuracy allowing the centers to export data from local systems and import the defined data to the eRDES. The process will aid in the best practices which have been defined by the Office of Biorepository and Biospecimen Research (OBBR) and the Group Banking Committee (GBC). The initiative allows for batch import and export, a data validation process and reporting mechanism, and a model for other labs to incorporate. All objectives are complete. The solutions provided and the defined process eliminates dual data entry resulting in data consistency. The audit trail capabilities allow for complete tracking of the data exchange between laboratories and the Statistical Data Center (SDC). The impact is directly on time and efforts. In return, the process will save money and improve the data utilized by the COG. Ongoing efforts include implementing new technologies to further enhance the current solutions and process currently in place. Web Services and Reporting Services are technologies that have become industry standards and will allow for further harmonization with caBIG …
Date: November 14, 2007
Creator: Reaman, Gregory
Object Type: Report
System: The UNT Digital Library
Analysis of Cost-Effective Off-Board Hydrogen Storage and Refueling Stations (open access)

Analysis of Cost-Effective Off-Board Hydrogen Storage and Refueling Stations

This report highlights design and component selection considerations for compressed gas hydrogen fueling stations operating at 5000 psig or 350 bar. The primary focus is on options for compression and storage – in terms of practical equipment options as well as various system configurations and how they influence delivery performance and station economics.
Date: November 14, 2008
Creator: Barnes, Ted & Liss, William
Object Type: Report
System: The UNT Digital Library
Experiments to Understand HPC Time to Development (Final report for Department of Energy contract DE-FG02-04ER25633) Report DOE/ER/25633-1 (open access)

Experiments to Understand HPC Time to Development (Final report for Department of Energy contract DE-FG02-04ER25633) Report DOE/ER/25633-1

In order to understand how high performance computing (HPC) programs are developed, a series of experiments, using students in graduate level HPC classes and various research centers, were conducted at various locations in the US. In this report, we discuss this research, give some of the early results of those experiments, and describe a web-based Experiment Manager we are developing that allows us to run studies more easily and consistently at universities and laboratories, allowing us to generate results that more accurately reflect the process of building HPC programs.
Date: November 14, 2007
Creator: Basili, Victor, R. & Zelkowitz, Marvin, V.
Object Type: Report
System: The UNT Digital Library
Lessons Learned (open access)

Lessons Learned

LLNL turned in 5 Declaration Line Items (DLI's) in 2006. Of these, one was declared completed. We made some changes to streamline our process from 2005, used less money, time and fewer team members. This report is a description of what changes we made in 2006 and what we learned. Many of our core review team had changed from last year, including our Laboratory Director, the Facility safety and security representatives, our Division Leader, and the OPSEC Committee Chair. We were able to hand out an AP Manual to some of them, and briefed all newcomers to the AP process. We first went to the OPSEC Committee and explained what the Additional Protocol process would be for 2006 and solicited their help in locating declarable projects. We utilized the 'three questions' from the AP meeting last year. LLNL has no single place to locate all projects at the laboratory. We talked to Resource Managers and key Managers in the Energy and Environment Directorate and in the Nonproliferation Homeland and International Security Directorate to find applicable projects. We also talked to the Principal Investigators who had projects last year. We reviewed a list of CRADA's and LDRD projects given to us …
Date: November 14, 2006
Creator: Dougan, A D & Blair, S
Object Type: Report
System: The UNT Digital Library
A Methodology to Measure Synergy Among Energy-Efficiency Programs at the Program Participant Level (open access)

A Methodology to Measure Synergy Among Energy-Efficiency Programs at the Program Participant Level

This paper presents a methodology designed to measure synergy among energy-efficiency programs at the program participant level (e.g., households, firms). Three different definitions of synergy are provided: strong, moderate, and weak. Data to measure synergy can be collected through simple survey questions. Straightforward mathematical techniques can be used to estimate the three types of synergy and explore relative synergistic impacts of different subsets of programs. Empirical research is needed to test the concepts and methods and to establish quantitative expectations about synergistic relationships among programs. The market for new energy-efficient motors is the context used to illustrate all the concepts and methods in this paper.
Date: November 14, 2003
Creator: Tonn, B.E.
Object Type: Report
System: The UNT Digital Library
Direct Observation of Cosmic Strings Via Their Strong Gravitational Lensing Effect. 1. Predictions for High Resolution Imaging Surveys (open access)

Direct Observation of Cosmic Strings Via Their Strong Gravitational Lensing Effect. 1. Predictions for High Resolution Imaging Surveys

We use current theoretical estimates for the density of long cosmic strings to predict the number of strong gravitational lensing events in astronomical imaging surveys as a function of angular resolution and survey area. We show that angular resolution is the single most important factor, and that interesting limits on the dimensionless string tension G{mu}/c{sup 2} can be obtained by existing and planned surveys. At the resolution of the Hubble Space Telescope (0'.14), it is sufficient to survey of order a square degree -- well within reach of the current HST archive -- to probe the regime G{mu}/c{sup 2} {approx} 10{sup -8}. If lensing by cosmic strings is not detected, such a survey would improve the limit on the string tension by an order of magnitude on that available from the cosmic microwave background. At the resolution (0'.028) attainable with the next generation of large ground based instruments, both in the radio and the infra-red with adaptive optics, surveying a sky area of order ten square degrees will allow us to probe the G{mu}/c{sup 2} {approx} 10{sup -9} regime. These limits will not be improved significantly by increasing the solid angle of the survey.
Date: November 14, 2007
Creator: Gasparini, Maria Alice; Marshall, Phil; Treu, Tommaso; /UC, Santa Barbara; Morganson, Eric; /KIPAC, Menlo Park et al.
Object Type: Article
System: The UNT Digital Library
In –Situ Spectroscopic Investigation of Immobilized Organometallic Catalysts (open access)

In –Situ Spectroscopic Investigation of Immobilized Organometallic Catalysts

Immobilized organometallic catalysts, in principle, can give high rates and selectivities like homogeneous catalysts with the ease of separation enjoyed by heterogeneous catalysts. However, the science of immobilized organometallics has not been developed because the field lies at the interface between the homogeneous and heterogeneous catalysis communities. By assembling an interdisciplinary research team that can probe all aspects of immobilized organometallic catalyst design, the entire reacting system can be considered, where the transition metal complex, the complex-support interface and the properties of the support can all be considered simultaneously from both experimental and theoretical points of view. Researchers at Georgia Tech and the University of Virginia are studying the fundamental principles that can be used to understand and design future classes of immobilized organometallic catalysts. In the framework of the overall collaborative project with Georgia Tech, our work focused on (a) the X-ray absorption spectroscopy of an immobilized Pd-SCS-O complex (b) the mode of metal leaching from supported Pd catalysts during Heck catalysis and (c) the mode of deactivation of Jacobsen’s Co-salen catalysts during the hydrolytic kinetic resolution of terminal epoxides. Catalysts containing supported Pd pincer complexes, functionalized supports containing mercapto and amine groups, and oligomeric Co-salen catalysts were synthesized …
Date: November 14, 2007
Creator: Davis, Robert, J.
Object Type: Report
System: The UNT Digital Library
AGN-Induced Cavities in NGC 1399 And NGC 4649 (open access)

AGN-Induced Cavities in NGC 1399 And NGC 4649

We present an analysis of archival Chandra and VLA observations of the E0 galaxy NGC1399 and the E2 galaxy NGC4649 in which we investigate cavities in the surrounding X-ray emitting medium caused by the central AGN. We calculate the jet power required for the AGN to evacuate these cavities and find values of {approx} 8x10{sup 41} erg s-1 and {approx} 14x10{sup 41} erg s{sup -1} for the lobes of NGC1399 and {approx} 7x10{sup 41} erg s{sup -1} and {approx} 6x1041 erg s{sup -1} for those of NGC4649. We also calculate the k/f values for each cavity, where k is the ratio of the total particle energy to that of electrons radiating in the range of 10 MHz to 10 GHz, and f is the volume filling factor of the plasma in the cavity. We find that the values of k/f for the lobes of NGC1399 are {approx} 93 and {approx} 190, and those of the lobes of NGC4649 are {approx} 15000 and {approx} 12000. We conclude that the assumed spectrum describes the electron distribution in the lobes of NGC1399 reasonably well, and that there are few entrained particles. For NGC4649, either there are many entrained particles or the model spectrum …
Date: November 14, 2007
Creator: Shurkin, K.; U., /New Mexico; Dunn, R. J. H.; U., /Southampton; Gentile, G.; Taylor, G. B. et al.
Object Type: Article
System: The UNT Digital Library
ELECTROCHEMICAL CORROSION TESTS FOR TANK 241-AY-101 CORE 325 SEGMENTS 16R1 & 16R2 (open access)

ELECTROCHEMICAL CORROSION TESTS FOR TANK 241-AY-101 CORE 325 SEGMENTS 16R1 & 16R2

The interstitial liquid in the double-shell tank 241-AY-101 settled solids layer is below the hydroxide chemistry control limit required by HNF-SD-WM-TSR-006, Tank Farms Technical Safety Requirements, Administrative Control 5.16, 'Corrosion Mitigation Controls'. Operating tanks outside of the specification may increase the propensity corrosion of the carbon steel wall. This report is concerned with generalized electrochemical corrosion mechanism that may occur at specific loci. All cyclic potentiodynamic polarization scans exhibited a negative hysteresis, scan reversing at lower current density, indicating that there was no pitting propensity. The general electrochemical corrosion rates ranged from 4.4E-02 to 1.5E-03 mpy with the first round of coupons, while the second round yielded corrosion rates of 2.5E-03 to 2.9E-02 mpy.
Date: November 14, 2007
Creator: JB, DUNCAN & RB, WYRWAS
Object Type: Report
System: The UNT Digital Library
VHE Gamma-Rays From Westerlund 2 And Implications for the Inferred Energetics (open access)

VHE Gamma-Rays From Westerlund 2 And Implications for the Inferred Energetics

The H.E.S.S. collaboration recently reported the discovery of VHE {gamma}-ray emission coincident with the young stellar cluster Westerlund 2. This system is known to host a population of hot, massive stars, and, most particularly, the WR binary WR 20a. Particle acceleration to TeV energies in Westerlund 2 can be accomplished in several alternative scenarios, therefore we only discuss energetic constraints based on the total available kinetic energy in the system, the actual mass loss rates of respective cluster members, and implied gamma-ray production from processes such as inverse Compton scattering or neutral pion decay. From the inferred gamma-ray luminosity of the order of 10{sup 35} erg/s, implications for the efficiency of converting available kinetic energy into non-thermal radiation associated with stellar winds in the Westerlund 2 cluster are discussed under consideration of either the presence or absence of wind clumping.
Date: November 14, 2007
Creator: Reimer, O.; /Stanford U., HEPL /KIPAC, Menlo Park; Aharonian, F.; /Heidelberg, Max Planck Inst. /Dublin Inst.; Hinton, J.; U., /Leeds et al.
Object Type: Article
System: The UNT Digital Library
Renormalization of Molecular Electronic Levels at Metal-MoleculeInterfaces (open access)

Renormalization of Molecular Electronic Levels at Metal-MoleculeInterfaces

None
Date: November 14, 2006
Creator: Neaton, Jeffrey B.; Hybertsen, Mark S. & Louie, Steven G.
Object Type: Article
System: The UNT Digital Library
Performance Contracting and Energy Efficiency in the State Government Market (open access)

Performance Contracting and Energy Efficiency in the State Government Market

There is growing interest in energy efficiency (EE) among state policymakers as a result of increasing environmental concerns, rising electricity and natural gas prices, and lean economic times that motivate states to look more aggressively for cost-saving opportunities in public sector buildings. One logical place for state policymakers to demonstrate their commitment to energy efficiency is to 'lead by example' by developing and implementing strategies to reduce the energy consumption of state government facilities through investments in energy efficient technologies. Traditionally, energy efficiency improvements at state government facilities are viewed as a subset in the general category of building maintenance and construction. These projects are typically funded through direct appropriations. However, energy efficiency projects are often delayed or reduced in scope whereby not all cost-effective measures are implemented because many states have tight capital budgets. Energy Savings Performance Contracting (ESPC) offers a potentially useful strategy for state program and facility managers to proactively finance and develop energy efficiency projects. In an ESPC project, Energy Service Companies (ESCOs) typically guarantee that the energy and cost savings produced by the project will equal or exceed all costs associated with implementing the project over the term of the contract. ESCOs typically provide turnkey …
Date: November 14, 2008
Creator: Bharvirkar, Ranjit; Goldman, Charles; Gilligan, Donald; Singer, Terry E.; Birr, David; Donahue, Patricia et al.
Object Type: Report
System: The UNT Digital Library
EXAMPLE OF A RISK BASED DISPOSAL APPROVAL SOLIDIFICATION OF HANFORD SITE TRANSURANIC (TRU) WASTE (open access)

EXAMPLE OF A RISK BASED DISPOSAL APPROVAL SOLIDIFICATION OF HANFORD SITE TRANSURANIC (TRU) WASTE

The Hanford Site requested, and the U.S. Environmental Protection Agency (EPA) Region 10 approved, a Toxic Substances Control Act of 1976 (TSCA) risk-based disposal approval (RBDA) for solidifying approximately four cubic meters of waste from a specific area of one of the K East Basin: the North Loadout Pit (NLOP). The NLOP waste is a highly radioactive sludge that contained polychlorinated biphenyls (PCBs) regulated under TSCA. The prescribed disposal method for liquid PCB waste under TSCA regulations is either thermal treatment or decontamination. Due to the radioactive nature of the waste, however, neither thermal treatment nor decontamination was a viable option. As a result, the proposed treatment consisted of solidifying the material to comply with waste acceptance criteria at the Waste Isolation Pilot Plant (WPP) in Carlsbad, New Mexico, or possibly the Environmental Restoration Disposal Facility at the Hanford Site, depending on the resulting transuranic (TRU) content of the stabilized waste. The RBDA evaluated environmental risks associated with potential airborne PCBs. In addition, the RBDA made use of waste management controls already in place at the treatment unit. The treatment unit, the T Plant Complex, is a Resource Conservation and Recovery Act of 1976 (RCRA)-permitted facility used for storing and …
Date: November 14, 2007
Creator: AL, PRIGNANO
Object Type: Article
System: The UNT Digital Library
Final-State Interactions and Single-Spin Asymmetries in Semi-inclusive Deep Inelastic Scattering (open access)

Final-State Interactions and Single-Spin Asymmetries in Semi-inclusive Deep Inelastic Scattering

Recent measurements from the HERMES and SMC collaborations show a remarkably large azimuthal single-spin asymmetries A{sub UL} and A{sub UT} of the proton in semi-inclusive pion leptoproduction {gamma}*(q)p {yields} {pi}X. We show that final-state interactions from gluon exchange between the outgoing quark and the target spectator system leads to single-spin asymmetries in deep inelastic lepton-proton scattering at leading twist in perturbative QCD; i.e., the rescattering corrections are not power-law suppressed at large photon virtuality q{sup 2} at fixed x{sub bj}. The existence of such single-spin asymmetries requires a phase difference between two amplitudes coupling the proton target with J{sup z}{sub p} = {+-}1/2 to the same final-state, the same amplitudes which are necessary to produce a nonzero proton anomalous magnetic moment. We show that the exchange of gauge particles between the outgoing quark and the proton spectators produces a Coulomb-like complex phase which depends on the angular momentum L{sup z} of the proton's constituents and thus is distinct for different proton spin amplitudes. The single-spin asymmetry which arises from such final-state interactions does not factorize into a product of structure function and fragmentation function, and it is not related to the transversity distribution {delta}q(x;Q) which correlates transversely polarized quarks with …
Date: November 14, 2007
Creator: Brodsky, Stanley J.; Hwang, Dae Sung & Schmidt, Ivan
Object Type: Article
System: The UNT Digital Library

Air Cooling Technology for Power Electronics Thermal Control

Assessing potential for air cooling in power electronics is a critical factor in power electronics equipment. NREL aims to assess effective air cooling techniques for power electronics technologies.
Date: November 14, 2007
Creator: Bharathan, D.
Object Type: Presentation
System: The UNT Digital Library