2012 Molecular Basis of Microbial One-Carbon Metabolism Gordon Research Conferences and Gordon Research Seminar, August 4-10,2012 (open access)

2012 Molecular Basis of Microbial One-Carbon Metabolism Gordon Research Conferences and Gordon Research Seminar, August 4-10,2012

The 2012 Gordon Conference will present and discuss cutting-edge research in the field of microbial metabolism of C1 compounds. The conference will feature the roles and application of C1 metabolism in natural and synthetic systems at scales from molecules to ecosystems. The conference will stress molecular aspects of the unique metabolism exhibited by autotrophic bacteria, methanogens, methylotrophs, aerobic and anaerobic methanotrophs, and acetogens.
Date: August 10, 2012
Creator: Hanson, Thomas
System: The UNT Digital Library
Spatially Resolved Study of Backscattering in the Quantum Spin Hall State (open access)

Spatially Resolved Study of Backscattering in the Quantum Spin Hall State

None
Date: December 10, 2012
Creator: Konig, Markus; Baenninger, Matthias; Garcia, Andrei G. F.; Harjee, Nahid; Pruitt, Beth L.; Ames, C. et al.
System: The UNT Digital Library
2012 Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring Technologies (open access)

2012 Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring Technologies

This Research is about Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring Technologies which presents a preliminary model of the three-dimensional seismic structure of the Iran region.
Date: September 10, 2012
Creator: Wetovsky, Marvin A.; Anderson, Dale; Arrowsmith, Stephen J.; Begnaud, Michael L.; Hartse, Hans E.; Maceira, Monica et al.
System: The UNT Digital Library
A 4.2 GS/sec. Synchronized Vertical Excitation System for SPS Studies - Steps Toward Wideband Feedback (open access)

A 4.2 GS/sec. Synchronized Vertical Excitation System for SPS Studies - Steps Toward Wideband Feedback

A 4.2 GS/sec. beam excitation system with accelerator synchronization and power stages is described. The system is capable of playing unique samples (32 samples/bunch) for 15,000 turns on selected bunch(es) in the SPS in syn- chronism with the injection and acceleration cycle. The purpose of the system is to excite internal modes of single-bunch vertical motion, and study the bunch dynamics in the presence of developing Electron cloud or TMCI effects. The system includes a synchronized master oscillator, SPS timing functions, an FPGA based arbitrary waveform generator, 4.2 GS/sec. D/A system and four 80W 20-1000 MHz amplifiers driving a tapered stripline pickup/kicker. A software GUI allows specification of various modulation signals, selection of bunches and turns to excite, while a remote control interface allows simple control/monitoring of the RF power stages located in the tunnel. The successful use of this system for SPS MD measurements in 2011 is a vital proof-of-principle for wideband feedback using similar functions to correct the beam motion.
Date: July 10, 2012
Creator: Fox, John
System: The UNT Digital Library
Analysis of ultra-narrow ferromagnetic domain walls (open access)

Analysis of ultra-narrow ferromagnetic domain walls

New materials with high magnetic anisotropy will have domains separated by ultra-narrow ferromagnetic walls with widths on the order of a few unit cells, approaching the limit where the elastic continuum approximation often used in micromagnetic simulations is accurate. The limits of this approximation are explored, and the static and dynamic interactions with intrinsic crystalline defects and external driving #12;elds are modeled. The results developed here will be important when considering the stability of ultra-high-density storage media.
Date: January 10, 2012
Creator: Jenkins, Catherine & Paul, David
System: The UNT Digital Library
Accelerating Atomic Orbital-based Electronic Structure Calculation via Pole Expansion plus Selected Inversion (open access)

Accelerating Atomic Orbital-based Electronic Structure Calculation via Pole Expansion plus Selected Inversion

We describe how to apply the recently developed pole expansion plus selected inversion (PEpSI) technique to Kohn-Sham density function theory (DFT) electronic structure calculations that are based on atomic orbital discretization. We give analytic expressions for evaluating charge density, total energy, Helmholtz free energy and atomic forces without using the eigenvalues and eigenvectors of the Kohn-Sham Hamiltonian. We also show how to update the chemical potential without using Kohn-Sham eigenvalues. The advantage of using PEpSI is that it has a much lower computational complexity than that associated with the matrix diagonalization procedure. We demonstrate the performance gain by comparing the timing of PEpSI with that of diagonalization on insulating and metallic nanotubes. For these quasi-1D systems, the complexity of PEpSI is linear with respect to the number of atoms. This linear scaling can be observed in our computational experiments when the number of atoms in a nanotube is larger than a few hundreds. Both the wall clock time and the memory requirement of PEpSI is modest. This makes it even possible to perform Kohn-Sham DFT calculations for 10,000-atom nanotubes on a single processor. We also show that the use of PEpSI does not lead to loss of accuracy required in …
Date: February 10, 2012
Creator: Lin, Lin; Chen, Mohan; Yang, Chao & He, Lixin
System: The UNT Digital Library
2012 VIBRATIONAL SPECTROSCOPY GORDON RESEARCH CONFERENCE, AUGUST 5-10, 2012 (open access)

2012 VIBRATIONAL SPECTROSCOPY GORDON RESEARCH CONFERENCE, AUGUST 5-10, 2012

The Vibrational Spectroscopy conference brings together experimentalists and theoreticians working at the frontiers of modern vibrational spectroscopy, with a special emphasis on spectroscopies that probe the structure and dynamics of molecules in gases, liquids, and at interfaces. The conference explores the wide range of state-of-the-art techniques based on vibrational motion. These techniques span the fields of time-domain, high-resolution frequency-domain, spatially-resolved, nonlinear, and multidimensional spectroscopies. The conference highlights both the application of these techniques in chemistry, materials, biology, the environment, and medicine as well as the development of theoretical models that enable one to connect spectroscopic signatures to underlying molecular motions including chemical reaction dynamics. The conference goal is to advance the field of vibrational spectroscopy by bringing together a collection of researchers who share common interests and who will gain from discussing work at the forefront of several connected areas. The intent is to emphasize the insights and understanding that studies of vibrations provide about a variety of molecular systems ranging from small polyatomic molecules to large biomolecules, nanomaterials, and environmental systems.
Date: August 10, 2012
Creator: Geiger, Franz
System: The UNT Digital Library
Mechanical Design of a High Energy Beam Absorber for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab (open access)

Mechanical Design of a High Energy Beam Absorber for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab

A high energy beam absorber has been built for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab. In the facility's initial configuration, an electron beam will be accelerated through 3 TTF-type or ILC-type SRF cryomodules to an energy of 750MeV. The electron beam will be directed to one of multiple downstream experimental and diagnostic beam lines and then deposited in one of two beam absorbers. The facility is designed to accommodate up to 6 cryomodules, which would produce a 75kW beam at 1.5GeV; this is the driving design condition for the beam absorbers. The beam absorbers consist of water-cooled graphite, aluminum and copper layers contained in a helium-filled enclosure. This paper describes the mechanical implementation of the beam absorbers, with a focus on thermal design and analysis. The potential for radiation-induced degradation of the graphite is discussed.
Date: May 10, 2012
Creator: Baffes, C.; Church, M.; Leibfritz, J.; Oplt, S. & Rakhno, I.
System: The UNT Digital Library
Advances in NIF Shock Timing Experiments (open access)

Advances in NIF Shock Timing Experiments

None
Date: July 10, 2012
Creator: Robey, H. F.; Celliers, P. M.; Moody, J. D. & MacKinnon, A. J.
System: The UNT Digital Library
QCD Analysis of the Scale-Invariance of Jets (open access)

QCD Analysis of the Scale-Invariance of Jets

None
Date: August 10, 2012
Creator: Larkoski, Andrew J.
System: The UNT Digital Library
Graphical User Interface Software for Gross Defect Detection at the Atucha-I Plant (open access)

Graphical User Interface Software for Gross Defect Detection at the Atucha-I Plant

At the Atucha-I pressurized heavy water reactor in Argentina, fuel assemblies in the spent fuel pools are stored by suspending them in two vertically stacked layers. This introduces the unique problem of verifying the presence of fuel in either layer without physically moving the fuel assemblies. Movement of fuel, especially from the lower layer, would involve a major effort on the part of the operator. Given that the facility uses both natural uranium and slightly enriched uranium at 0.85 w% {sup 235}U, and has been in operation since 1974, a wide range of burnups and cooling times can exist in any given pool. Additionally, while fuel assemblies are grouped together in a uniform fashion, the packing density from group to group can vary within a single pool. A tool called the Spent Fuel Neutron Counter (SFNC) was developed and successfully tested at the site to verify, in an in-situ condition, the presence of fuel up to burnups of 8,000 MWd/t. Since the neutron source term becomes a nonlinear function of burnup beyond this burnup, a new algorithm was developed to predict expected response from the SFNC at measurement locations covering the entire range of burnups, cooling times, and initial enrichments. …
Date: May 10, 2012
Creator: Wong, Alden C.; Sitaraman, Shivakumar; Ham, Young S. & Peixoto, Orpet J. M.
System: The UNT Digital Library
The role of members of viral quasispecies in adaptation to new host environments (open access)

The role of members of viral quasispecies in adaptation to new host environments

None
Date: February 10, 2012
Creator: Borucki, M.; Allen, J. E.; Chen-Harris, H.; Mabery, S.; Vanier, G.; Torres, C. et al.
System: The UNT Digital Library
Challenges of 4th Generation Light Sources (open access)

Challenges of 4th Generation Light Sources

This report talks about Challenges of 4th Generation Light Sources
Date: December 10, 2012
Creator: Pellegrini, C.
System: The UNT Digital Library
Measurements of the Electron Cloud Density in the PEP-II Low Energy Ring (open access)

Measurements of the Electron Cloud Density in the PEP-II Low Energy Ring

Clouds of low energy electrons in the vacuum beam pipes of accelerators of positively charged particle beams present a serious limitation for operation of these machines at high currents. Because of the size of these accelerators, it is difficult to probe the low energy electron clouds over substantial lengths of the beam pipe. We have developed a novel technique to directly measure the electron cloud density via the phase shift induced in a TE wave that is independently excited and transmitted over a section of the accelerator. We infer the absolute phase shift with relatively high accuracy from the phase modulation of the transmission due to the modulation of the electron cloud density from a gap in the positively charged beam. We have used this technique for the first time to measure the average electron cloud density over a 50 m straight section in the positron ring of the PEP-II collider at the Stanford Linear Accelerator Center. We have also measured the variation of the density by using low field solenoid magnets to control the electrons.
Date: April 10, 2012
Creator: Byrd, J.; De Santis, S.; Sonnad, K.; Caspers, F.; Kroyer, T.; Krasnykh, A. et al.
System: The UNT Digital Library
Search for the Z_1(4050)^+ and Z_2(4250)^+ States in bar B^0 to chi_{c1} K^- pi^+ and B^+ to chi_{c1} K^0_S pi^+ (open access)

Search for the Z_1(4050)^+ and Z_2(4250)^+ States in bar B^0 to chi_{c1} K^- pi^+ and B^+ to chi_{c1} K^0_S pi^+

We search for the Z{sub 1}(4050){sup +} and Z{sub 2}(4250){sup +} states, reported by the Belle Collaboration, decaying to {chi}{sub c1}{pi}{sup +} in the decays {bar B}{sup 0} {yields} {chi}{sub c1}K{sup -}{pi}{sup +} and B{sup +} {yields} {chi}{sub c1}K{sub S}{sup 0}{pi}{sup +} where {chi}{sub c1} {yields} J/{psi}{gamma}. The data were collected with the BABAR detector at the SLAC PEP-II asymmetric-energy e{sup +}e{sup -} collider operating at center-of-mass energy 10.58 GeV, and correspond to an integrated luminosity of 429 fb{sup -1}. In this analysis, we model the background-subtracted, efficiency-corrected {chi}{sub c1}{pi}{sup +} mass distribution using the K{pi} mass distribution and the corresponding normalized K{pi} Legendre polynomial moments, and then test the need for the inclusion of resonant structures in the description of the {chi}{sub c1}{pi}{sup +} mass distribution. No evidence is found for the Z{sub 1}(4050){sup +} and Z{sub 2}(4250){sup +} resonances, and 90% confidence level upper limits on the branching fractions are reported for the corresponding B-meson decay modes.
Date: April 10, 2012
Creator: Lees, J. P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M. et al.
System: The UNT Digital Library
CEMENTITIOUS GROUT FOR CLOSING SRS HIGH LEVEL WASTE TANKS - #12315 (open access)

CEMENTITIOUS GROUT FOR CLOSING SRS HIGH LEVEL WASTE TANKS - #12315

In 1997, the first two United States Department of Energy (US DOE) high level waste tanks (Tanks 17-F and 20-F: Type IV, single shell tanks) were taken out of service (permanently closed) at the Savannah River Site (SRS). In 2012, the DOE plans to remove from service two additional Savannah River Site (SRS) Type IV high-level waste tanks, Tanks 18-F and 19-F. These tanks were constructed in the late 1950's and received low-heat waste and do not contain cooling coils. Operational closure of Tanks 18-F and 19-F is intended to be consistent with the applicable requirements of the Resource Conservation and Recovery Act (RCRA) and the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and will be performed in accordance with South Carolina Department of Health and Environmental Control (SCDHEC). The closure will physically stabilize two 4.92E+04 cubic meter (1.3 E+06 gallon) carbon steel tanks and isolate and stabilize any residual contaminants left in the tanks. The closure will also fill, physically stabilize and isolate ancillary equipment abandoned in the tanks. A Performance Assessment (PA) has been developed to assess the long-term fate and transport of residual contamination in the environment resulting from the operational closure of the F-Area Tank …
Date: January 10, 2012
Creator: Langton, C.; Burns, H. & Stefanko, D.
System: The UNT Digital Library
Lepton Universality Test in Upsilon(1S) Decays at BaBar (open access)

Lepton Universality Test in Upsilon(1S) Decays at BaBar

Using a sample of 122 million {Upsilon}(3S) decays collected with the BABAR detector at the PEP-II asymmetric energy collider at the SLAC National Accelerator Laboratory, we measure the ratio R{sub {tau}{mu}} = BR({Upsilon}(1S) {yields} {tau}{sup +}{tau}{sup -})/BR({Upsilon}(1S) {yields} {mu}{sup +}{mu}{sup -}); the measurement is intended as a test of lepton universality and as a possible search for a light pseudoscalar Higgs boson in Next to Minimal Supersymmetric Standard Model (NMSSM) scenarios. Such a boson could appear in a deviation of the ratio R{sub {tau}{mu}} from the Standard Model expectation, that is 1, except for small lepton mass corrections. The analysis exploits the decays {Upsilon}(3S) {yields} {Upsilon}(1S){pi}{sup +}{pi}{sup -}, {Upsilon}(1S) {yields} l{sup +}l{sup -}, where l = {mu},{tau}.
Date: April 10, 2012
Creator: Guido, Elisa & /Genoa U. /INFN, Genoa
System: The UNT Digital Library
BLENDING ANALYSIS FOR RADIOACTIVE SALT WASTE PROCESSING FACILITY (open access)

BLENDING ANALYSIS FOR RADIOACTIVE SALT WASTE PROCESSING FACILITY

Savannah River National Laboratory (SRNL) evaluated methods to mix and blend the contents of the blend tanks to ensure the contents are properly blended before they are transferred from the blend tank such as Tank 21 and Tank 24 to the Salt Waste Processing Facility (SWPF) feed tank. The tank contents consist of three forms: dissolved salt solution, other waste salt solutions, and sludge containing settled solids. This paper focuses on developing the computational model and estimating the operation time of submersible slurry pump when the tank contents are adequately blended prior to their transfer to the SWPF facility. A three-dimensional computational fluid dynamics approach was taken by using the full scale configuration of SRS Type-IV tank, Tank 21H. Major solid obstructions such as the tank wall boundary, the transfer pump column, and three slurry pump housings including one active and two inactive pumps were included in the mixing performance model. Basic flow pattern results predicted by the computational model were benchmarked against the SRNL test results and literature data. Tank 21 is a waste tank that is used to prepare batches of salt feed for SWPF. The salt feed must be a homogeneous solution satisfying the acceptance criterion of …
Date: May 10, 2012
Creator: Lee, S.
System: The UNT Digital Library
Mode-Locked Multichromatic X-Rays in a Seeded Free-Electron Laser for Single-Shot X-Ray Spectroscopy (open access)

Mode-Locked Multichromatic X-Rays in a Seeded Free-Electron Laser for Single-Shot X-Ray Spectroscopy

We present the promise of generating gigawatt mode-locked multichromatic x rays in a seeded free-electron laser (FEL). We show that, by using a laser to imprint periodic modulation in electron beam phase space, a single-frequency coherent seed can be amplified and further translated to a mode-locked multichromatic output in an FEL. With this configuration the FEL output consists of a train of mode-locked ultrashort pulses which span a wide frequency gap with a series of equally spaced sharp lines. These gigawatt multichromatic x rays may potentially allow one to explore the structure and dynamics of a large number of atomic states simultaneously. The feasibility of generating mode-locked x rays ranging from carbon K edge ({approx}284 eV) to copper L{sub 3} edge ({approx}931 eV) is confirmed with numerical simulation using the realistic parameters of the linac coherent light source (LCLS) and LCLS-II. We anticipate that the mode-locked multichromatic x rays in FELs may open up new opportunities in x-ray spectroscopy (i.e. resonant inelastic x-ray scattering, time-resolved scattering and spectroscopy, etc.).
Date: May 10, 2012
Creator: Xiang, Dao; Ding, Yuantao; Raubenheimer, Tor & Wu, Juhao
System: The UNT Digital Library
Dalitz Plot Analyses of B- to D+ Pi- Pi-, B+ to Pi+ Pi- Pi+ and D(S)+ to Pi+ Pi- Pi+ at BaBar (open access)

Dalitz Plot Analyses of B- to D+ Pi- Pi-, B+ to Pi+ Pi- Pi+ and D(S)+ to Pi+ Pi- Pi+ at BaBar

We report on the Dalitz plot analyses of B{sup -} {yields} D{sup +}{pi}{sup -}{pi}{sup -}, B{sup +} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup +} and D{sub s}{sup +} {yields} {pi}{sup +}{pi}{sup -}{sup +}. The Dalitz plot method and the most recent BABAR results are discussed.
Date: April 10, 2012
Creator: Dong, Liaoyuan & U., /Iowa State
System: The UNT Digital Library
Measuring Sparticles with the Matrix Element (open access)

Measuring Sparticles with the Matrix Element

We apply the Matrix Element Method (MEM) to mass determination of squark pair production with direct decay to quarks and LSP at the LHC, showing that simultaneous mass determination of squarks and LSP is possible. We furthermore propose methods for inclusion of QCD radiation effects in the MEM. The goal of the LHC at CERN, scheduled to start this year, is to discover new physics through deviations from the Standard Model (SM) predictions. After discovery of deviations from the SM, the next step will be classification of the new physics. An important first goal in this process will be establishing a mass spectrum of the new particles. One of the most challenging scenarios is pair-production of new particles which decay to invisible massive particles, giving missing energy signals. Many methods have been proposed for mass determination in such scenarios (for a recent list of references, see e.g. [1]). In this proceeding, we report the first steps in applying the Matrix Element Method (MEM) in the context of supersymmetric scenarios giving missing energy signals. After a quick review of the MEM, we will focus on squark pair production, a process where other mass determination techniques have difficulties to simultaneously determine the …
Date: April 10, 2012
Creator: Alwall, Johan; /SLAC /Taiwan, Natl. Taiwan U.; Freitas, Ayres; U., /Pittsburgh; Mattelaer, Olivier & /INFN, Rome3 /Rome III U. /Louvain U.
System: The UNT Digital Library
The SM and NLO Multileg Working Group: Summary Report (open access)

The SM and NLO Multileg Working Group: Summary Report

After years of waiting, and after six Les Houches workshops, the era of LHC running is finally upon us, albeit at a lower initial center-of-mass energy than originally planned. Thus, there has been a great sense of anticipation from both the experimental and theoretical communities. The last two years, in particular, have seen great productivity in the area of multi-parton calculations at leading order (LO), next-to-leading order (NLO) and next-to-next-to-leading order (NNLO), and this productivity is reflected in the proceedings of the NLM group. Both religions, Feynmanians and Unitarians, as well as agnostic experimenters, were well-represented in both the discussions at Les Houches, and in the contributions to the write-up. Next-to-leading order (NLO) is the first order at which the normalization, and in some cases the shape, of perturbative cross sections can be considered reliable. This can be especially true when probing extreme kinematic regions, as for example with boosted Higgs searches considered in several of the contributions to this writeup. A full understanding for both standard model and beyond the standard model physics at the LHC requires the development of fast, reliable programs for the calculation of multi-parton final states at NLO. There have been many advances in the …
Date: April 10, 2012
Creator: Andersen, J. R.; Archibald, J.; Badger, S.; Ball, R. D.; Bevilacqua, G.; Bierenbaum, I. et al.
System: The UNT Digital Library
FUNDAMENTAL ENVIRONMENTAL REACTIVITY TESTING AND ANALYSIS OF THE HYDROGEN STORAGE MATERIAL 2LIBH4 MGH2 (open access)

FUNDAMENTAL ENVIRONMENTAL REACTIVITY TESTING AND ANALYSIS OF THE HYDROGEN STORAGE MATERIAL 2LIBH4 MGH2

While the storage of hydrogen for portable and stationary applications is regarded as critical in bringing PEM fuel cells to commercial acceptance, little is known of the environmental exposure risks posed in utilizing condensed phase chemical storage options as in complex hydrides. It is thus important to understand the effect of environmental exposure of metal hydrides in the case of accident scenarios. Simulated tests were performed following the United Nations standards to test for flammability and water reactivity in air for a destabilized lithium borohydride and magnesium hydride system in a 2 to 1 molar ratio respectively. It was determined that the mixture acted similarly to the parent, lithium borohydride, but at slower rate of reaction seen in magnesium hydride. To quantify environmental exposure kinetics, isothermal calorimetry was utilized to measure the enthalpy of reaction as a function of exposure time to dry and humid air, and liquid water. The reaction with liquid water was found to increase the heat flow significantly during exposure compared to exposure in dry or humid air environments. Calorimetric results showed the maximum normalized heat flow the fully charged material was 6 mW/mg under liquid phase hydrolysis; and 14 mW/mg for the fully discharged material …
Date: January 10, 2012
Creator: James, C.; Anton, D.; Cortes-Concepcion, J.; Brinkman, K. & Gray, J.
System: The UNT Digital Library
BENEFITS OF VIBRATION ANALYSIS FOR DEVELOPMENT OF EQUIPMENT IN HLW TANKS - 12341 (open access)

BENEFITS OF VIBRATION ANALYSIS FOR DEVELOPMENT OF EQUIPMENT IN HLW TANKS - 12341

Vibration analyses of equipment intended for use in the Savannah River Site (SRS) radioactive liquid waste storage tanks are performed during pre-deployment testing and has been demonstrated to be effective in reducing the life-cycle costs of the equipment. Benefits of using vibration analysis to identify rotating machinery problems prior to deployment in radioactive service will be presented in this paper. Problems encountered at SRS and actions to correct or lessen the severity of the problem are discussed. In short, multi-million dollar cost saving have been realized at SRS as a direct result of vibration analysis on existing equipment. Vibration analysis of equipment prior to installation can potentially reduce inservice failures, and increases reliability. High-level radioactive waste is currently stored in underground carbon steel waste tanks at the United States Department of Energy (DOE) Savannah River Site and at the Hanford Site, WA. Various types of rotating machinery (pumps and separations equipment) are used to manage and retrieve the tank contents. Installation, maintenance, and repair of these pumps and other equipment are expensive. In fact, costs to remove and replace a single pump can be as high as a half million dollars due to requirements for radioactive containment. Problems that lead …
Date: January 10, 2012
Creator: Stefanko, D. & Herbert, J.
System: The UNT Digital Library