ARM Climate Research Facility Monthly Instrument Report July 2010 (open access)

ARM Climate Research Facility Monthly Instrument Report July 2010

The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following five sections: (1) new instrumentation in the process of being acquired and deployed, (2) field campaigns, (3) existing instrumentation and progress on improvements or upgrades, (4) proposed future instrumentation, and (5) Small Business Innovation Research instrument development.
Date: August 18, 2010
Creator: Voyles, J. W.
Object Type: Report
System: The UNT Digital Library
MODELING THE IMPACT OF ELEVATED MERCURY IN DEFENSE WASTE PROCESSING FACILITY MELTER FEED ON THE MELTER OFF-GAS SYSTEM-PRELIMINARY REPORT (open access)

MODELING THE IMPACT OF ELEVATED MERCURY IN DEFENSE WASTE PROCESSING FACILITY MELTER FEED ON THE MELTER OFF-GAS SYSTEM-PRELIMINARY REPORT

The Defense Waste Processing Facility (DWPF) is currently evaluating an alternative Chemical Process Cell (CPC) flowsheet to increase throughput. It includes removal of the steam-stripping step, which would significantly reduce the CPC processing time and lessen the sampling needs. However, its downside would be to send 100% of the mercury that comes in with the sludge straight to the melter. For example, the new mercury content in the Sludge Batch 5 (SB5) melter feed is projected to be 25 times higher than that in the SB4 with nominal steam stripping of mercury. This task was initiated to study the impact of the worst-case scenario of zero-mercury-removal in the CPC on the DWPF melter offgas system. It is stressed that this study is intended to be scoping in nature, so the results presented in this report are preliminary. In order to study the impact of elevated mercury levels in the feed, it is necessary to be able to predict how mercury would speciate in the melter exhaust under varying melter operating conditions. A homogeneous gas-phase oxidation model of mercury by chloride was developed to do just that. The model contains two critical parameters pertaining to the partitioning of chloride among HCl, …
Date: August 18, 2010
Creator: Zamecnik, J. & Choi, A.
Object Type: Report
System: The UNT Digital Library
Optimization of Hydroacoustic Equipment Deployments at Lookout Point and Cougar Dams, Willamette Valley Project, 2010 (open access)

Optimization of Hydroacoustic Equipment Deployments at Lookout Point and Cougar Dams, Willamette Valley Project, 2010

The goal of the study was to optimize performance of the fixed-location hydroacoustic systems at Lookout Point Dam (LOP) and the acoustic imaging system at Cougar Dam (CGR) by determining deployment and data acquisition methods that minimized structural, electrical, and acoustic interference. The general approach was a multi-step process from mount design to final system configuration. The optimization effort resulted in successful deployments of hydroacoustic equipment at LOP and CGR.
Date: August 18, 2010
Creator: Johnson, Gary E.; Khan, Fenton; Ploskey, Gene R.; Hughes, James S. & Fischer, Eric S.
Object Type: Report
System: The UNT Digital Library
Overview of the Physics and Engineering Design of NSTX Upgrade (open access)

Overview of the Physics and Engineering Design of NSTX Upgrade

None
Date: August 18, 2011
Creator: et. al, J M
Object Type: Article
System: The UNT Digital Library
Beam Transport in a Proton Dielectric Wall Accelerator (open access)

Beam Transport in a Proton Dielectric Wall Accelerator

None
Date: August 18, 2010
Creator: Chen, Y.; Caporaso, G.; Blackfield, D.; Hawkins, S.; Nelson, S. & Poole, B.
Object Type: Article
System: The UNT Digital Library
Comparison of u.s. Seismic Fragility Data With Jnes Test Data for Motor-Operated Valves, Fans, and Tanks (open access)

Comparison of u.s. Seismic Fragility Data With Jnes Test Data for Motor-Operated Valves, Fans, and Tanks

N/A
Date: August 18, 2013
Creator: J., Nie; C., Hofmayer & Stovall, S.
Object Type: Article
System: The UNT Digital Library
Kull Shock Propagation Verification on Paved Mesh Geometries (open access)

Kull Shock Propagation Verification on Paved Mesh Geometries

None
Date: August 18, 2011
Creator: Cunningham, A J
Object Type: Report
System: The UNT Digital Library
Undulator K Value Temperature Dependence (open access)

Undulator K Value Temperature Dependence

None
Date: August 18, 2011
Creator: Wolf, Zachary & Levashov, Yurii
Object Type: Report
System: The UNT Digital Library
A STUDY OF THE EFFECT OF FLOOR FLEXIBILITY ON BUILDING RESPONSE USING THE KK NPP EXPERIENCE (open access)

A STUDY OF THE EFFECT OF FLOOR FLEXIBILITY ON BUILDING RESPONSE USING THE KK NPP EXPERIENCE

N/A
Date: August 18, 2013
Creator: J., Nie; J., Braverman; Hofmayer, C. & Stovall, S.
Object Type: Article
System: The UNT Digital Library
California GAMA Special Study: Ion exchange and trace element surface complexation reactions associated with applied recharge of low-TDS water in the San Joaquin Valley, California (open access)

California GAMA Special Study: Ion exchange and trace element surface complexation reactions associated with applied recharge of low-TDS water in the San Joaquin Valley, California

None
Date: August 18, 2010
Creator: McNab, W. W.; Singleton, M. J.; Moran, J. E. & Esser, B. K.
Object Type: Report
System: The UNT Digital Library
Advanced Gated X-Ray Imagers for Experiments at the National Ignition Facility (open access)

Advanced Gated X-Ray Imagers for Experiments at the National Ignition Facility

None
Date: August 18, 2011
Creator: Glenn, S.; Bell, P.; Benedetti, L.; Bradley, D.; Celeste, J.; Heeter, R. et al.
Object Type: Article
System: The UNT Digital Library
Descriptor-Based Analysis Applied to HCN Synthesis from NH3 and CH4 (open access)

Descriptor-Based Analysis Applied to HCN Synthesis from NH3 and CH4

The design of solid metal catalysts using theoretical methods has been a long-standing goal in heterogeneous catalysis. Recent developments in methodology and computer technology as well as the establishment of a descriptor-based approach for the analysis of reaction mechanisms and trends across the periodic table allow for the fast screening for new catalytic materials and have lead to first examples of computational discoveries of new materials. The underlying principles of the descriptor-based approach are the existence of relations between the surface electronic structure, adsorption energies and activation barriers that result in volcano-shaped activity plots as function of simple descriptors, such as atomic binding energies or the d-band center. Linear scaling relations have been established between the adsorption energies of hydrogen-containing molecules such as CH{sub x}, NH{sub x}, OH{sub x} and SH{sub x} and the C, N O and S adsorption energies on transition-metal surfaces. Transition-state energies have also been shown to scale linearly with adsorption energies in a similar fashion. Recently, a single transition state scaling relation has been identified for a large number of C-C, C-O, C-N, N-O, N-N, and O-O coupling reactions. The scaling relations provide a powerful tool for the investigation of reaction mechanisms and the prediction …
Date: August 18, 2011
Creator: Grabow, L
Object Type: Article
System: The UNT Digital Library
ARM Climate Research Facility Quarterly Value-Added Product Report Third Quarter: April 01–June 30, 2011 (open access)

ARM Climate Research Facility Quarterly Value-Added Product Report Third Quarter: April 01–June 30, 2011

The purpose of this report is to provide a concise status update for value-added products (VAP) implemented by the Atmospheric Radiation Measurement Climate Research Facility. The report is divided into the following sections: (1) new VAPs for which development has begun, (2) progress on existing VAPs, (3) future VAPs that have been recently approved, (4) other work that leads to a VAP, and (5) top requested VAPs from the archive
Date: August 18, 2011
Creator: Sivaraman, C
Object Type: Report
System: The UNT Digital Library
Isospin Splittings of Doubly Heavy Baryons (open access)

Isospin Splittings of Doubly Heavy Baryons

The SELEX Collaboration has reported a very large isospin splitting of doubly charmed baryons. We show that this effect would imply that the doubly charmed baryons are very compact. One intriguing possibility is that such baryons have a linear geometry Q-q-Q where the light quark q oscillates between the two heavy quarks Q, analogous to a linear molecule such as carbon dioxide. However, using conventional arguments, the size of a heavy-light hadron is expected to be around 0.5 fm, much larger than the size needed to explain the observed large isospin splitting. Assuming the distance between two heavy quarks is much smaller than that between the light quark and a heavy one, the doubly heavy baryons are related to the heavy mesons via heavy quark-diquark symmetry. Based on this symmetry, we predict the isospin splittings for doubly heavy baryons including {Xi}{sub cc}, {Xi}{sub bb} and {Xi}{sub bc}. The prediction for the {Xi}{sub cc} is much smaller than the SELEX value. On the other hand, the {Xi}{sub bb} baryons are predicted to have an isospin splitting as large as (6.3 {+-} 1.7) MeV. An experimental study of doubly bottomed baryons is therefore very important to better understand the structure of baryons …
Date: August 18, 2011
Creator: Brodsky, Stanley J.; Guo, Feng-Kun; Hanhart, Christoph & Meissner, Ulf-G.
Object Type: Article
System: The UNT Digital Library
Nuclear Data Resources for Capture gamma-Ray Spectroscopy and Related Topics (open access)

Nuclear Data Resources for Capture gamma-Ray Spectroscopy and Related Topics

Nuclear reaction data play an important role in nuclear reactor, medical, and fundamental science and national security applications. The wealth of information is stored in internally adopted ENDF-6 and EXFOR formats. We present a complete calculation of resonance integrals, Westcott factors, thermal and Maxwellian-averaged cross sections for Z = 1-100 using evaluated nuclear reaction data. The addition of newly-evaluated neutron reaction libraries, and improvements in data processing techniques allows us to calculate nuclear industry and astrophysics parameters, and provide additional insights on all currently available neutron-induced reaction data. Nuclear reaction calculations will be discussed and an overview of the latest reaction data developments will be given.
Date: August 18, 2011
Creator: Pritychenko, B. & Pritychenko,B.
Object Type: Report
System: The UNT Digital Library
On the Kinematics of Undulator Girder Motion (open access)

On the Kinematics of Undulator Girder Motion

The theory of rigid body kinematics is used to derive equations that govern the control and measurement of the position and orientation of undulator girders. The equations form the basis of the girder matlab software on the LCLS control system. The equations are linear for small motion and easily inverted as desired. For reference, some relevant girder geometrical data is also given. Equations 6-8 relate the linear potentiometer readings to the motion of the girder. Equations 9-11 relate the cam shaft angles to the motion of the girder. Both sets are easily inverted to either obtain the girder motion from the angles or readings, or, to find the angles and readings that would give a desired motion. The motion of any point on the girder can be calculated by applying either sets of equations to the two cam-planes and extrapolating in the z coordinate using equation 19. The formulation of the equations is quite general and easily coded via matrix and vector methods. They form the basis of the girder matlab software on the LCLS control system.
Date: August 18, 2011
Creator: Welch, J
Object Type: Report
System: The UNT Digital Library
The Atacama Cosmology Telescope: Cosmology from Galaxy Clusters Detected via the Sunyaev-Zel'dovich Effect (open access)

The Atacama Cosmology Telescope: Cosmology from Galaxy Clusters Detected via the Sunyaev-Zel'dovich Effect

We present constraints on cosmological parameters based on a sample of Sunyaev-Zeldovich-selected galaxy clusters detected in a millimeter-wave survey by the Atacama Cosmology Telescope. The cluster sample used in this analysis consists of 9 optically-confirmed high-mass clusters comprising the high-significance end of the total cluster sample identified in 455 square degrees of sky surveyed during 2008 at 148GHz. We focus on the most massive systems to reduce the degeneracy between unknown cluster astrophysics and cosmology derived from SZ surveys. We describe the scaling relation between cluster mass and SZ signal with a 4-parameter fit. Marginalizing over the values of the parameters in this fit with conservative priors gives {sigma}{sub 8} = 0.851 {+-} 0.115 and w = -1.14 {+-} 0.35 for a spatially-flat wCDM cosmological model with WMAP 7-year priors on cosmological parameters. This gives a modest improvement in statistical uncertainty over WMAP 7-year constraints alone. Fixing the scaling relation between cluster mass and SZ signal to a fiducial relation obtained from numerical simulations and calibrated by X-ray observations, we find {sigma}{sub 8} = 0.821 {+-} 0.044 and w = -1.05 {+-} 0.20. These results are consistent with constraints from WMAP 7 plus baryon acoustic oscillations plus type Ia supernoava …
Date: August 18, 2011
Creator: Sehgal, Neelima; Trac, Hy; Acquaviva, Viviana; Ade, Peter A.R.; Aguirre, Paula; Amiri, Mandana et al.
Object Type: Article
System: The UNT Digital Library
Suppression of Beam-Ion Instability in Electron Rings with Multi-Bunch Train Beam Fillings (open access)

Suppression of Beam-Ion Instability in Electron Rings with Multi-Bunch Train Beam Fillings

The ion-caused beam instability in the future light sources and electron damping rings can be serious due to the high beam current and ultra-small emittance of picometer level. One simple and effective mitigation of the instability is a multi-bunch train beam filling pattern which can significantly reduce the ion density near the beam, and therefore reduce the instability growth rate up to two orders of magnitude. The suppression is more effective for high intensity beams with low emittance. The distribution and the field of trapped ions are benchmarked to validate the model used in the paper. The wake field of ion-cloud and the beam-ion instability is investigated both analytically and numerically. We derived a simple formula for the build-up of ion-cloud and instability growth rate with the multi-bunch-train filling pattern. The ion instabilities in ILC damping ring, SuperKEKB and SPEAR3 are used to compare with our analyses. The analyses in this paper agree well with simulations.
Date: August 18, 2011
Creator: Wang, L.; Cai, Y.; Raubenheimer, T. O. & Fukuma, H.
Object Type: Article
System: The UNT Digital Library
Six Thousand Electrochemical Cycles of Double-Walled Silicon Nanotube Anodes for Lithium Ion Batteries (open access)

Six Thousand Electrochemical Cycles of Double-Walled Silicon Nanotube Anodes for Lithium Ion Batteries

Despite remarkable progress, lithium ion batteries still need higher energy density and better cycle life for consumer electronics, electric drive vehicles and large-scale renewable energy storage applications. Silicon has recently been explored as a promising anode material for high energy batteries; however, attaining long cycle life remains a significant challenge due to materials pulverization during cycling and an unstable solid-electrolyte interphase. Here, we report double-walled silicon nanotube electrodes that can cycle over 6000 times while retaining more than 85% of the initial capacity. This excellent performance is due to the unique double-walled structure in which the outer silicon oxide wall confines the inner silicon wall to expand only inward during lithiation, resulting in a stable solid-electrolyte interphase. This structural concept is general and could be extended to other battery materials that undergo large volume changes.
Date: August 18, 2011
Creator: Wu, H
Object Type: Article
System: The UNT Digital Library
Studies of Ds Decays at BaBar (open access)

Studies of Ds Decays at BaBar

We present a measurement of the absolute branching fractions {Beta}(D{sub s}{sup -} {yields} {mu}{sup -}{bar {nu}}{sub {mu}}) and {Beta}(D{sub s}{sup -} {yields} {tau}{sup -}{bar {nu}}{sub {tau}}) and of the D{sub s} decay constant, f{sub D{sub s}}. They also obtain an upper limit on {Beta}(D{sub s}{sup -} {yields} e{bar {nu}}{sub e}). Then they present results on Dalitz plot analysis of D{sub s}{sup +} decays to K{sup +}K{sup -}{pi}{sup +} and {pi}{sup +}{pi}{sup -}{pi}{sup +}. The {pi}{sup +}{pi}{sup -} and K{sup +}K{sup -} S-waves are extracted by a model-independent partial wave analysis. Finally they measure relative branching fractions of D{sub s}{sup +} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup +}, D{sub s}{sup +} {yields} K{sup +}K{sup -}K{sup +}, and D{sub s}{sup +} {yields} K{sup +}K{sup +}{pi}{sup -} relative to D{sub s}{sup +} {yields} K{sup +}K{sup -}{pi}{sup +}. All the results make use of data collected by the BABAR detector at the PEP-II storage rings at SLAC.
Date: August 18, 2011
Creator: Pappagallo, Marco
Object Type: Article
System: The UNT Digital Library
EFFECTS OF NITRIC ACID ON CRITICALITY SAFETY ANALYSIS (open access)

EFFECTS OF NITRIC ACID ON CRITICALITY SAFETY ANALYSIS

As nitric acid molarity is increased, there are two competing phenomena affecting the reactivity of the system. First, there is interaction between each of the 10 wells in the basket-like insert. As the molarity of the nitric acid solution is increased (it moves from 100% water to 100% HNO{sub 3}), the hydrogen atom density decreases by about 80%. However, it remains a relatively efficient moderator. The moderating ratio of nitric acid is about 90% that of water. As the media between the wells is changed from 100% water to 100% nitric acid, the density of the media increases by 50%. A higher density typically leads to a better reflector. However, when the macroscopic scattering cross sections are considered, nitric acid is a much worse reflector than water. The effectiveness of nitric acid as a reflector is about 40% that of water. Since the media between the wells become a worse reflector and still remains an effective moderator, interaction between the wells increases. This phenomenon will cause reactivity to increase as nitric acid molarity increases. The seond phenomenon is due to the moderating ratio changing in the high concentration fissile-nitric acid solution in the 10 wells. Since the wells contain relatively …
Date: August 18, 2011
Creator: Williamson, B.
Object Type: Article
System: The UNT Digital Library
Single Dirac Cone Topological Surface State and Unusual Thermoelectric Property of Compounds from a New Topological Insulator Family (open access)

Single Dirac Cone Topological Surface State and Unusual Thermoelectric Property of Compounds from a New Topological Insulator Family

Angle resolved photoemission spectroscopy (ARPES) study on TlBiTe2 and TlBiSe2 from a Thallium-based III-V-VI2 ternary chalcogenides family revealed a single surface Dirac cone at the center of the Brillouin zone for both compounds. For TlBiSe{sub 2}, the large bulk gap ({approx} 200meV) makes it a topological insulator with better mechanical properties than the previous binary 3D topological insualtor family. For TlBiTe{sub 2}, the observed negative bulk gap indicates it as a semi-metal, rather than a narrow gap semi-conductor as conventionally believed; this semi-metality naturally explains its mysteriously small thermoelectric figure of merit comparing to other compounds in the family. Finally, the unique band structures of TlBiTe{sub 2} also suggests it as a candidate for topological superconductors.
Date: August 18, 2011
Creator: Chen, Y.
Object Type: Article
System: The UNT Digital Library
Scaling Relationships for Adsorption Energies of C2 Hydrocarbons on Transition Metal Surfaces (open access)

Scaling Relationships for Adsorption Energies of C2 Hydrocarbons on Transition Metal Surfaces

Using density functional theory calculations we show that the adsorption energies for C{sub 2}H{sub x}-type adsorbates on transition metal surfaces scale with each other according to a simple bond order conservation model. This observation generalizes some recently recognized adsorption energy scaling laws for AH{sub x}-type adsorbates to unsaturated hydrocarbons and establishes a coherent simplified description of saturated as well as unsaturated hydrocarbons adsorbed on transition metal surfaces. A number of potential applications are discussed. We apply the model to the dehydrogenation of ethane over pure transition metal catalysts. Comparison with the corresponding full density functional theory calculations shows excellent agreement.
Date: August 18, 2011
Creator: Jones, G
Object Type: Article
System: The UNT Digital Library
Trapping of Electron Cloud LLC/Cesrta Quadrupole and Sextupole Magnets (open access)

Trapping of Electron Cloud LLC/Cesrta Quadrupole and Sextupole Magnets

The Cornell Electron Storage Ring (CESR) has been reconfigured as an ultra low emittance damping ring for use as a test accelerator (CesrTA) for International Linear Collider (ILC) damping ring R&D [1]. One of the primary goals of the CesrTA program is to investigate the interaction of the electron cloud with low emittance positron beam to explore methods to suppress the electron cloud, develop suitable advanced instrumentation required for these experimental studies and benchmark predictions by simulation codes. This paper reports the simulation of the electron-cloud formation in CESRTA and ILC quadrupole and sextupole magnets using the 3D code CLOUDLAND. We found that electrons can be trapped with a long lifetime in a quadrupole and sextupole magnet due to the mirror field trapping mechanism. We study the effects of magnet strength, bunch current, ante-chamber effect, bunch spacing effect and secondary emission yield (SEY) in great detail. The development of an electron cloud in magnets is the main concern where a weak solenoid field is not effective. Quadrupole and sextupole magnets have mirror field configurations which may trap electrons by the mirror field trapping mechanism [2]. Fig.1 shows the orbit of a trapped electron in a quadrupole magnet. The electron makes …
Date: August 18, 2011
Creator: Wang, L. & Pivi, M.
Object Type: Report
System: The UNT Digital Library