NASA COR (open access)

NASA COR

None
Date: August 14, 2012
Creator: Sandoval, P
Object Type: Report
System: The UNT Digital Library
A Natural Language for AdS/CFT Correlators (open access)

A Natural Language for AdS/CFT Correlators

We provide dramatic evidence that 'Mellin space' is the natural home for correlation functions in CFTs with weakly coupled bulk duals. In Mellin space, CFT correlators have poles corresponding to an OPE decomposition into 'left' and 'right' sub-correlators, in direct analogy with the factorization channels of scattering amplitudes. In the regime where these correlators can be computed by tree level Witten diagrams in AdS, we derive an explicit formula for the residues of Mellin amplitudes at the corresponding factorization poles, and we use the conformal Casimir to show that these amplitudes obey algebraic finite difference equations. By analyzing the recursive structure of our factorization formula we obtain simple diagrammatic rules for the construction of Mellin amplitudes corresponding to tree-level Witten diagrams in any bulk scalar theory. We prove the diagrammatic rules using our finite difference equations. Finally, we show that our factorization formula and our diagrammatic rules morph into the flat space S-Matrix of the bulk theory, reproducing the usual Feynman rules, when we take the flat space limit of AdS/CFT. Throughout we emphasize a deep analogy with the properties of flat space scattering amplitudes in momentum space, which suggests that the Mellin amplitude may provide a holographic definition of …
Date: February 14, 2012
Creator: Fitzpatrick, A. Liam; Kaplan, Jared; Penedones, Joao; Raju, Suvrat & van Rees, Balt C.
Object Type: Article
System: The UNT Digital Library
Constraints on Dark Matter Annihilation in Clusters of Galaxies with the Fermi Large Area Telescope (open access)

Constraints on Dark Matter Annihilation in Clusters of Galaxies with the Fermi Large Area Telescope

None
Date: December 14, 2012
Creator: Ackermann, M.; Ajello, M.; Allafort, A.; Baldini, L.; Ballet, J.; Barbiellini, G. et al.
Object Type: Article
System: The UNT Digital Library
Application of the Principle of Maximum Conformality to the Top-Quark Forward-Backward Asymmetry at the Tevatron (open access)

Application of the Principle of Maximum Conformality to the Top-Quark Forward-Backward Asymmetry at the Tevatron

The renormalization scale uncertainty can be eliminated by the Principle of Maximum Conformality (PMC) in a systematic scheme-independent way. Applying the PMC for the t{bar t}-pair hadroproduction at the NNLO level, we have found that the total cross-sections {sigma}{sub t{bar t}} at both the Tevatron and LHC remain almost unchanged when taking very disparate initial scales {mu}{sub R}{sup init} equal to m{sub t}, 10 m{sub t}, 20 m{sub t} and {radical}s, which is consistent with renormalization group invariance. As an important new application, we apply PMC scale-setting to study the top-quark forward-backward asymmetry. We observe that the more convergent perturbative series after PMC scale-setting leads to a more accurate top-quark forward-backward asymmetry. The resulting PMC prediction on the asymmetry is also free from the initial renormalization scale-dependence. Because the NLO PMC scale has a dip behavior for the (q{bar q})-channel at small subprocess collision energies, the importance of this channel to the asymmetry is increased. We observe that the asymmetries A{sub FB}{sup t{bar t}} and A{sub FB}{sup p{bar p}} at the Tevatron will be increased by 42% in comparison to the previous estimates obtained by using conventional scale-setting; i.e. we obtain A{sub FB}{sup t{bar t}PMC} {approx_equal} 12.5% and A{sub FB}{sup …
Date: May 14, 2012
Creator: Brodsky, Stanley J. & Wu, Xing-Gang
Object Type: Article
System: The UNT Digital Library
High Power UV LED Industrial Curing Systems (open access)

High Power UV LED Industrial Curing Systems

UV curing is a green technology that is largely underutilized because UV radiation sources like Hg Lamps are unreliable and difficult to use. High Power UV LEDs are now efficient enough to replace Hg Lamps, and offer significantly improved performance relative to Hg Lamps. In this study, a modular, scalable high power UV LED curing system was designed and tested, performing well in industrial coating evaluations. In order to achieve mechanical form factors similar to commercial Hg Lamp systems, a new patent pending design was employed enabling high irradiance at long working distances. While high power UV LEDs are currently only available at longer UVA wavelengths, rapid progress on UVC LEDs and the development of new formulations designed specifically for use with UV LED sources will converge to drive more rapid adoption of UV curing technology. An assessment of the environmental impact of replacing Hg Lamp systems with UV LED systems was performed. Since UV curing is used in only a small portion of the industrial printing, painting and coating markets, the ease of use of UV LED systems should increase the use of UV curing technology. Even a small penetration of the significant number of industrial applications still using …
Date: May 14, 2012
Creator: Karlicek, Robert, F., Jr & Sargent, Robert
Object Type: Report
System: The UNT Digital Library
Mechanistic Studies at the Interface Between Organometallic Chemistry and Homogeneous Catalysis (open access)

Mechanistic Studies at the Interface Between Organometallic Chemistry and Homogeneous Catalysis

Mechanistic Studies at the Interface Between Organometallic Chemistry and Homogeneous Catalysis Charles P. Casey, Principal Investigator Department of Chemistry, University of Wisconsin - Madison, Madison, Wisconsin 53706 Phone 608-262-0584 FAX: 608-262-7144 Email: casey@chem.wisc.edu http://www.chem.wisc.edu/main/people/faculty/casey.html Executive Summary. Our goal was to learn the intimate mechanistic details of reactions involved in homogeneous catalysis and to use the insight we gain to develop new and improved catalysts. Our work centered on the hydrogenation of polar functional groups such as aldehydes and ketones and on hydroformylation. Specifically, we concentrated on catalysts capable of simultaneously transferring hydride from a metal center and a proton from an acidic oxygen or nitrogen center to an aldehyde or ketone. An economical iron based catalyst was developed and patented. Better understanding of fundamental organometallic reactions and catalytic processes enabled design of energy and material efficient chemical processes. Our work contributed to the development of catalysts for the selective and mild hydrogenation of ketones and aldehydes; this will provide a modern green alternative to reductions by LiAlH4 and NaBH4, which require extensive work-up procedures and produce waste streams. (C5R4OH)Ru(CO)2H Hydrogenation Catalysts. Youval Shvo described a remarkable catalytic system in which the key intermediate (C5R4OH)Ru(CO)2H (1) has an electronically coupled acidic …
Date: November 14, 2012
Creator: Casey, Charles P.
Object Type: Report
System: The UNT Digital Library
Comparison of CDMS [100] and [111] Oriented Germanium Detectors (open access)

Comparison of CDMS [100] and [111] Oriented Germanium Detectors

The Cryogenic Dark Matter Search (CDMS) utilizes large mass, 3-inch diameter x 1-inch thick target masses as particle detectors. The target is instrumented with both phonon and ionization sensors and comparison of energy in each channel provides event-by-event classification of electron and nuclear recoils. Fiducial volume is determined by the ability to obtain good phonon and ionization signal at a particular location. Due to electronic band structure in germanium, electron mass is described by an anisotropic tensor with heavy mass aligned along the symmetry axis defined by the [111] Miller index (L valley), resulting in large lateral component to the transport. The spatial distribution of electrons varies significantly for detectors which have their longitudinal axis orientations described by either the [100] or [111] Miller indices. Electric fields with large fringing component at high detector radius also affect the spatial distribution of electrons and holes. Both effects are studied in a 3 dimensional Monte Carlo and the impact on fiducial volume is discussed.
Date: September 14, 2012
Creator: Leman, S. W.; Hertel, S. A.; /MIT, MKI; Kim, P.; /SLAC; Cabrera, B. et al.
Object Type: Article
System: The UNT Digital Library
Scattering States in AdS/CFT (open access)

Scattering States in AdS/CFT

We show that suitably regulated multi-trace primary states in large N CFTs behave like 'in' and 'out' scattering states in the flat-space limit of AdS. Their transition matrix elements approach the exact scattering amplitudes for the bulk theory, providing a natural CFT definition of the flat space S-Matrix. We study corrections resulting from the AdS curvature and particle propagation far from the center of AdS, and show that AdS simply provides an IR regulator that disappears in the flat space limit.
Date: February 14, 2012
Creator: Fitzpatrick, A.Liam; U., /Boston & Kaplan, Jared
Object Type: Report
System: The UNT Digital Library
Improving the Fermilab Booster Notching Efficiency, Beam Losses and Radiation Levels (open access)

Improving the Fermilab Booster Notching Efficiency, Beam Losses and Radiation Levels

A fast vertical 1.08-m long kicker (notcher) located in the Fermilab Booster Long-05 straight section is currently used to remove 3 out of 84 circulating bunches after injection to generate an abort gap. With the maximum magnetic field of 72.5 Gauss, it removes only 87% of the 3-bunch intensity at 400 MeV, with 75% loss on pole tips of the focusing Booster magnets, 11% on the Long-06 collimators, and 1% in the rest of the ring. We propose to improve the notching efficiency and reduce beam loss in the Booster by using three horizontal kickers in the Long-12 section. STRUCT calculations show that using horizontal notchers, one can remove up to 96% of the 3-bunch intensity at 400-700 MeV, directing 95% of it to a new beam dump at the Long-13 section. This fully decouples notching and collimation. The beam dump absorbs most of the impinging proton energy in its jaws. The latter are encapsulated into an appropriate radiation shielding that reduces impact on the machine components, personnel and environment to the tolerable levels. MARS simulations show that corresponding prompt and residual radiation levels can be reduced ten times compared to the current ones.
Date: May 14, 2012
Creator: Rakhno, I. L.; Drozhdin, A. I.; Mokhov, N. V.; Sidorov, V. I. & Tropin, I. S.
Object Type: Article
System: The UNT Digital Library
Development of Electronics for the ATF2 Interaction Point Region Beam Position Monitor (open access)

Development of Electronics for the ATF2 Interaction Point Region Beam Position Monitor

Nanometer resolution beam position monitors have been developed to measure and control beam position stability at the interaction point region of ATF2. The position of the beam has to be measured to within a few nanometers at the interaction point. In order to achieve this performance, electronics for the low-Q IP-BPM was developed. Every component of the electronics have been simulated and checked on the bench and using the ATF2 beam. We will explain each component and define their working range. Then, we will show the performance of the electronics measured with beam signal. ATF2 is a final focus test beam line for ILC in the framework of the ATF international collaboration. The new beam line was constructed to extend the extraction line at ATF, KEK, Japan. The first goal of ATF2 is the acheiving of a 37 nm vertical beam size at focal point (IP). The second goal is to stabilize the beam at the focal point at a few nanometer level for a long period in order to ensure the high luminosity. To achieve these goals a high resolution IP-BPM is essential. In addition for feedback applications a low-Q system is desirable.
Date: August 14, 2012
Creator: Kim, Youngim; U., /Kyungpook Natl.; Heo, Ae-young; U., /Kyungpook Natl.; Kim, Eun-San; U., /Kyungpook Natl. et al.
Object Type: Article
System: The UNT Digital Library
Soil Composition, Area 6 of the Nevada National Security Site (open access)

Soil Composition, Area 6 of the Nevada National Security Site

None
Date: September 14, 2012
Creator: Knight, K B
Object Type: Report
System: The UNT Digital Library
Institute for Scalable Application Development Software (open access)

Institute for Scalable Application Development Software

Work by the University of Wisconsin as part of the DOE SciDAC CScADS includes the following accomplishments: � Research on tool componentization, with concentration on the: � InstructionAPI and InstructionSemanticsAPI � ParseAPI � DataflowAPI � Co-organized a series of high successful workshops with Prof. John Mellor-Crummey, Rice University, on Performance Tools for Petascale Computing, held in Snowbird, Utah and Lake Tahoe, California in July or August of 2007 through 2012. � Investigated the use of multicore in numerical libraries � Dyninst porting to 32- and 64bit Power/PowerPC (including BlueGene) and 32- and 64-bit Pentium platforms. � Applying our toolkits to advanced problems in binary code parsing associated with dealing with legacy and malicious code.
Date: November 14, 2012
Creator: Miller, Barton P.
Object Type: Report
System: The UNT Digital Library
Evaluation of Representative Smart Grid Investment Grant Project Technologies: Thermal Energy Storage (open access)

Evaluation of Representative Smart Grid Investment Grant Project Technologies: Thermal Energy Storage

This document is one of a series of reports estimating the benefits of deploying technologies similar to those implemented on the Smart Grid Investment Grant (SGIG) projects. Four technical reports cover the various types of technologies deployed in the SGIG projects, distribution automation, demand response, energy storage, and renewables integration. A fifth report in the series examines the benefits of deploying these technologies on a national level. This technical report examines the impacts of energy storage technologies deployed in the SGIG projects.
Date: February 14, 2012
Creator: Tuffner, Francis K. & Bonebrake, Christopher A.
Object Type: Report
System: The UNT Digital Library
HFC Concrete: A Low-Energy, Carbon-Dioxide-­Negative Solution for reducing Industrial Greenhouse Gas Emissions (open access)

HFC Concrete: A Low-Energy, Carbon-Dioxide-­Negative Solution for reducing Industrial Greenhouse Gas Emissions

Solidia/CCSM received funding for further research and development of its Low Temperature Solidification Process (LTS), which is used to create hydrate-free concrete (HFC). LTS/HFC is a technology/materials platform that offers wide applicability in the built infrastructure. Most importantly, it provides a means of making concrete without Portland cement. Cement and concrete production is a major consumer of energy and source of industrial greenhouse gas (GHG) emissions. The primary goal of this project was to develop and commercialize a novel material, HFC, which by replacing traditional concrete and cement, reduces both energy use and GHG emissions in the built infrastructure. Traditional concrete uses Portland Cement (PC) as a binder. PC production involves calcination of limestone at {approx}1450 C, which releases significant amounts of CO{sub 2} gas to the atmosphere and consumes a large amount of energy due to the high temperature required. In contrast, HFC is a carbonate-based hydrate-free concrete (HFC) that consumes CO{sub 2} gas in its production. HFC is made by reaction of silicate minerals with CO{sub 2} at temperatures below 100 C, more than an order-of-magnitude below the temperature required to make PC. Because of this significant difference in temperature, it is estimated that we will be able …
Date: May 14, 2012
Creator: McCandlish, Larry & Riman, Richard
Object Type: Report
System: The UNT Digital Library
SuperB Progress Report: Detector (open access)

SuperB Progress Report: Detector

This report describes the present status of the detector design for SuperB. It is one of four separate progress reports that, taken collectively, describe progress made on the SuperB Project since the publication of the SuperB Conceptual Design Report in 2007 and the Proceedings of SuperB Workshop VI in Valencia in 2008.
Date: February 14, 2012
Creator: Grauges, E.; /Barcelona U., ECM; Donvito, G.; Spinoso, V.; /INFN, Bari /Bari U.; Manghisoni, M. et al.
Object Type: Report
System: The UNT Digital Library
REVISED GUIDELINES FOR USING CELLULOSE DEGRADATION PRODUCT-IMPACTED KD VALUES FOR PERFORMANCE ASSESSMENTS AND COMPOSITE ANALYSES (open access)

REVISED GUIDELINES FOR USING CELLULOSE DEGRADATION PRODUCT-IMPACTED KD VALUES FOR PERFORMANCE ASSESSMENTS AND COMPOSITE ANALYSES

Cellulosic materials include wood, paper, rags, and cardboard products. These materials are co-disposed with radiological waste at the Savannah River Site's (SRS) E-Area Low-Level Waste Facility (ELLWF). Cellulosic materials readily degrade in the environment to form cellulose degradation products (CDP) that will partition to the sediment or remain mobile in the groundwater. Savannah River National Lab (SRNL) has conducted studies to estimate the impact of CDP on radionuclide sorption to SRS sediments (Kd values). It was found that CDP impact on radionuclide sorption varies with radionuclide and CDP concentration. Furthermore, it was found that the amount of carbon (C) in the system could increase or decrease Kd values with respect to the base case of when no CDP was added. Throughout the expected pH range of the ELLWF, a low concentration of CDP in the system would increase Kd values (because C would sorb to the sediment and provide more exchange sites for radionuclides to sorb), whereas greater concentrations of CDP ({ge}20 mg/L C) would decrease Kd values (because C would remain in solution and complex the radionuclide and not permit the radionuclide to sorb to the sediment). A review of >230 dissolved organic carbon (DOC) groundwater concentrations in the …
Date: May 14, 2012
Creator: Kaplan, D.
Object Type: Report
System: The UNT Digital Library
Higher Order Modes HOM___s in Coupled Cavities of the Flash Module ACC39 (open access)

Higher Order Modes HOM___s in Coupled Cavities of the Flash Module ACC39

We analyse the higher order modes (HOM's) in the 3.9GHz bunch shaping cavities installed in the FLASH facility at DESY. A suite of finite element computer codes (including HFSS and ACE3P) and globalised scattering matrix calculations (GSM) are used to investigate the modes in these cavities. This study is primarily focused on the dipole component of the multiband expansion of the wakefield, with the emphasis being on the development of a HOM-based BPM system for ACC39. Coupled inter-cavity modes are simulated together with a limited band of trapped modes.
Date: September 14, 2012
Creator: Shinton, I. R. R.; Jones, R. M.; Li, Z. & Zhang, P.
Object Type: Article
System: The UNT Digital Library
Observation of Supernova Remnant IC 443 with the Fermi Large Area Telescope (open access)

Observation of Supernova Remnant IC 443 with the Fermi Large Area Telescope

None
Date: December 14, 2012
Creator: Abdo, A. A.
Object Type: Report
System: The UNT Digital Library
Computational and Experimental Design of Fe-Based Superalloys for Elevated-Temperature Applications (open access)

Computational and Experimental Design of Fe-Based Superalloys for Elevated-Temperature Applications

Analogous to nickel-based superalloys, Fe-based superalloys, which are strengthened by coherent B2- type precipitates are proposed for elevated-temperature applications. During the period of this project, a series of ferritic superalloys have been designed and fabricated by methods of vacuum-arc melting and vacuum-induction melting. Nano-scale precipitates were characterized by atom-probe tomography, ultrasmall- angle X-ray scattering, and transmission-electron microscopy. A duplex distribution of precipitates was found. It seems that ferritic superalloys are susceptible to brittle fracture. Systematic endeavors have been devoted to understanding and resolving the problem. Factors, such as hot rolling, precipitate volume fractions, alloy compositions, precipitate sizes and inter-particle spacings, and hyperfine cooling precipitates, have been investigated. In order to understand the underlying relationship between the microstructure and creep behavior of ferric alloys at elevated temperatures, in-situ neutron studies have been carried out. Based on the current result, it seems that the major role of β΄ with a 16%-volume fraction in strengthening ferritic alloys is not load sharing but interactions with dislocations. The oxidation behavior of one ferritic alloy, FBB8 (Fe-6.5Al-10Ni-10Cr-3.4Mo-0.25Zr-0.005B, weight percent), was studied in dry air. It is found that it possesses superior oxidation resistance at 1,023 and 1,123 K, compared with other creep-resistant ferritic steels [T91 (modified …
Date: January 14, 2012
Creator: Liaw, Peter K.; Fine, Morris E.; Ghosh, Gautam; Asta, Mark D.; Liu, Chain T.; Sun, Zhiqian et al.
Object Type: Report
System: The UNT Digital Library
Electron Charged Graphite-based Hydrogen Storage Material (open access)

Electron Charged Graphite-based Hydrogen Storage Material

The electron-charge effects have been demonstrated to enhance hydrogen storage capacity using materials which have inherent hydrogen storage capacities. A charge control agent (CCA) or a charge transfer agent (CTA) was applied to the hydrogen storage material to reduce internal discharge between particles in a Sievert volumetric test device. GTI has tested the device under (1) electrostatic charge mode; (2) ultra-capacitor mode; and (3) metal-hydride mode. GTI has also analyzed the charge distribution on storage materials. The charge control agent and charge transfer agent are needed to prevent internal charge leaks so that the hydrogen atoms can stay on the storage material. GTI has analyzed the hydrogen fueling tank structure, which contains an air or liquid heat exchange framework. The cooling structure is needed for hydrogen fueling/releasing. We found that the cooling structure could be used as electron-charged electrodes, which will exhibit a very uniform charge distribution (because the cooling system needs to remove heat uniformly). Therefore, the electron-charge concept does not have any burden of cost and weight for the hydrogen storage tank system. The energy consumption for the electron-charge enhancement method is quite low or omitted for electrostatic mode and ultra-capacitor mode in comparison of other hydrogen storage …
Date: March 14, 2012
Creator: 0812, Dr. Chinbay Q. Fan R&D Manager Office of Technology and Innovations Phone: 847 768
Object Type: Report
System: The UNT Digital Library
Gravitomagnetism and Spinor Quantum Mechanics (open access)

Gravitomagnetism and Spinor Quantum Mechanics

We give a systematic treatment of a spin 1=2 particle in a combined electromagnetic field and a weak gravitational field that is produced by a slowly moving matter source. This paper continues previous work on a spin zero particle, but it is largely self-contained and may serve as an introduction to spinors in a Riemann space. The analysis is based on the Dirac equation expressed in generally covariant form and coupled minimally to the electromagnetic field. The restriction to a slowly moving matter source, such as the earth, allows us to describe the gravitational field by a gravitoelectric (Newtonian) potential and a gravitomagnetic (frame-dragging) vector potential, the existence of which has recently been experimentally verified. Our main interest is the coupling of the orbital and spin angular momenta of the particle to the gravitomagnetic field. Specifically we calculate the gravitational gyromagnetic ratio as g{sub g} = 1 ; this is to be compared with the electromagnetic gyromagnetic ratio of g{sub e} = 2 for a Dirac electron.
Date: September 14, 2012
Creator: Adler, Ronald J.; /Stanford U., HEPL /San Francisco State U.; Chen, Pisin; /Taiwan, Natl. Taiwan U. /KIPAC, Menlo Park /SLAC; Varani, Elisa & /Unlisted
Object Type: Article
System: The UNT Digital Library
The Conceptional Design of the Shielding Layout and Beam Absorber at the PXIE (open access)

The Conceptional Design of the Shielding Layout and Beam Absorber at the PXIE

Project X is a high intensity proton facility conceived to support a world-leading physics program at Fermilab. Project X will provide high intensity beams for neutrino, kaon, muon, and nuclei based experiments and for studies supporting energy applications. The Project X Injector Experiment (PIXIE) is a prototype of the Project X front end. A 30 MeV 50 kW beam will be used to validate the design concept of the Project X. This paper discusses a design of the accelerator enclosure radiation shielding and the beam dump.
Date: May 14, 2012
Creator: Eidelman, Yu.; Kerby, J.; Lebedev, V.; Leibfritz, J.; Leveling, T.; Nagaisev, S. et al.
Object Type: Article
System: The UNT Digital Library
Halo-to-Halo Similarity and Scatter in the Velocity Distribution of Dark Matter (open access)

Halo-to-Halo Similarity and Scatter in the Velocity Distribution of Dark Matter

Examines the velocity distribution function (VDF) in dark matter halos from milky way to cluster mass scales.
Date: December 14, 2012
Creator: Mao, Yao-Yuan; Strigari, Louis E.; Wechsler, Risa H.; Wu, Hao-Yi & Hahn, Oliver
Object Type: Article
System: The UNT Digital Library
Evaluation of Representative Smart Grid Investment Project Technologies: Demand Response (open access)

Evaluation of Representative Smart Grid Investment Project Technologies: Demand Response

This document is one of a series of reports estimating the benefits of deploying technologies similar to those implemented on the Smart Grid Investment Grant (SGIG) projects. Four technical reports cover the various types of technologies deployed in the SGIG projects, distribution automation, demand response, energy storage, and renewables integration. A fifth report in the series examines the benefits of deploying these technologies on a national level. This technical report examines the impacts of a limited number of demand response technologies and implementations deployed in the SGIG projects.
Date: February 14, 2012
Creator: Fuller, Jason C.; Prakash Kumar, Nirupama & Bonebrake, Christopher A.
Object Type: Report
System: The UNT Digital Library