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When the guest of honor is a party pro, it better be good: Austin fête celebrates author (open access)

When the guest of honor is a party pro, it better be good: Austin fête celebrates author

Article about Lara Shriftman and Elizabeth Harrison, co-owners of marketing, public relations, and planning firm Harrison & Shriftman and co-authors of the book "Party Confidential."
Date: November 26, 2006
Creator: Scheidnes, Jean
System: The UNT Digital Library
Assessing field-scale migration of mobile radionuclides at the Nevada Test Site (open access)

Assessing field-scale migration of mobile radionuclides at the Nevada Test Site

Numerous long-lived radionuclides, including {sup 99}Tc (technetium) and {sup 129}I (iodine), are present in groundwater at the Nevada Test Site (NTS) as a result of 828 underground nuclear weapons tests conducted between 1951 and 1992. We synthesize a body of groundwater data collected on the distribution of a number of radionuclides ({sup 3}H, {sup 14}C, {sup 36}Cl, {sup 99}Tc and {sup 129}I), which are presumably mobile in the subsurface and potentially toxic to down-gradient receptors, to assess their migration at NTS, at field scales over distances of hundreds of meters and for durations of more than thirty years. Qualitative evaluation of field-scale migration of these radionuclides in the saturated zone provides an independent approach to validating their presumably conservative transport in the performance assessment of the proposed geological repository at Yucca Mountain, which is located on the western edge of NTS. The analyses show that the interaction of {sup 3}H with a solid surface via an isotopic exchange with clay lattice hydroxyls may cause a slight delay in the transport of {sup 3}H. The transport of {sup 14}C could be retarded by its isotopic exchange with carbonate minerals, and the exchange may be more pronounced in the alluvial aquifer. In …
Date: September 26, 2006
Creator: Hu, Q.; Rose, T. P.; Smith, D. K.; Moran, J. E. & Zavarin, M.
System: The UNT Digital Library
A 15-T Pulsed Solenoid for a High-Power Target Experiment (open access)

A 15-T Pulsed Solenoid for a High-Power Target Experiment

The MERIT experiment, to be run at CERN in 2007, is a proof-of-principle test for a target system that converts a 4-MW proton beam into a high-intensity muon beam for either a neutrino factory complex or a muon collider. The target system is based on a free mercury jet that intercepts an intense proton beam inside a 15-T solenoidal magnetic field. Here, we describe the design and initial performance of the 15-T, liquid-nitrogen-precooled, copper solenoid magnet.
Date: June 26, 2006
Creator: Kirk, H. G.; Efthymiopoulos, I.; Fabich, A.; Haug, R.; Titus, P.; McDonald, K. T. et al.
System: The UNT Digital Library
Choice of Proton Driver Parameters for a Neutrino Factory (open access)

Choice of Proton Driver Parameters for a Neutrino Factory

We discuss criteria for designing an optimal 'green field' proton driver for a neutrino factory. The driver parameters are determined by considerations of space charge, power capabilities of the target, beam loading and available RF peak power. A neutrino factory may be the best experimental tool to unravel the physics involved in neutrino oscillation and CP violation phenomena [1]. To have sufficient neutrino flux for acceptable physics results within 5 years requires about 10{sup 22} protons on target per year, which corresponds to 1-4 MW of proton beam power from the proton driver depending on the beam energy. In the past, there were individual proposals from different laboratories of a particular design of proton driver capable of delivering beam power from 2 to 4 MW, without consistent attention paid to the needs or requirements from the downstream systems. In this study, we try to identify the requirements from those down stream systems first, then see whether it is possible to design a proton driver to meet those needs. Such a study will also assist site specific proposals to further improve on their designs to better serve the need of a proton driver for neutrino factory applications.
Date: June 26, 2006
Creator: Kirk, H. G.; Berg, J. S.; Fernow, R. C.; Gallardo, J. C.; Simos, N.; Weng, W. T. et al.
System: The UNT Digital Library
A Proof-of-Principal Experiment for a High-Power Target System (open access)

A Proof-of-Principal Experiment for a High-Power Target System

The MERIT experiment, to be run at CERN in 2007, is a proof-of-principle test for a target system that converts a 4-MW proton beam into a high-intensity muon beam for either a neutrino factory complex or a muon collider. The target system is based on a free mercury jet that intercepts an intense proton beam inside a 15-T solenoidal magnetic field. A muon collider or neutrino factory requires intense beams of muons, which are obtained from the decay of pions. Pion production by a proton beam is maximized by use of a high-Z target such as mercury. A liquid jet target has the advantages over a solid target that a flowing jet can readily remove heat and that it is immune to radiation damage. However the proton beam energy disrupts the jet and the system could be operationally unstable. Efficient capture of low-energy secondary pions (for transfer into the subsequent muon accelerator complex) requires that the target system be immersed in a strong magnetic field of solenoidal geometry. This magnetic field should stabilize the mercury flow in regions of nearly uniform field, but it perturbs the liquid metal jet as it enters the field. Hence, the behavior of the mercury …
Date: June 26, 2006
Creator: Kirk, H. G.; Samulyak, R.; Simos, N.; Tsang, T.; Efthymiopoulos, I.; Fabich, A. et al.
System: The UNT Digital Library
Melting of bcc Transition Metals and Icosahedral Clustering (open access)

Melting of bcc Transition Metals and Icosahedral Clustering

In contrast to polyvalent metals, transition metals have low melting slopes(dT/dP) that are due to partially filled d-bands that allow for a lowering of liquid phase energy through s-d electron transfer and the formation of local structures. In the case of bcc transition metals we show the apparent discrepancy of DAC melting measurements with shock melting of Mo can be understood by reexamining the shock data for V and Ta and introducing the presence of an icosahedral short range order (ISRO) melt phase.
Date: May 26, 2006
Creator: Ross, M; Boehler, R & Japel, S
System: The UNT Digital Library
Towards an Accurate Performance Modeling of Parallel SparseFactorization (open access)

Towards an Accurate Performance Modeling of Parallel SparseFactorization

We present a performance model to analyze a parallel sparseLU factorization algorithm on modern cached-based, high-end parallelarchitectures. Our model characterizes the algorithmic behavior bytakingaccount the underlying processor speed, memory system performance, aswell as the interconnect speed. The model is validated using theSuperLU_DIST linear system solver, the sparse matrices from realapplications, and an IBM POWER3 parallel machine. Our modelingmethodology can be easily adapted to study performance of other types ofsparse factorizations, such as Cholesky or QR.
Date: May 26, 2006
Creator: Grigori, Laura & Li, Xiaoye S.
System: The UNT Digital Library
Cobra-IE Evaluation by Simulation of the NUPEC BWR Full-Size Fine-Mesh Bundle Test (BFBT) (open access)

Cobra-IE Evaluation by Simulation of the NUPEC BWR Full-Size Fine-Mesh Bundle Test (BFBT)

The COBRA-IE computer code is a thermal-hydraulic subchannel analysis program capable of simulating phenomena present in both PWRs and BWRs. As part of ongoing COBRA-IE assessment efforts, the code has been evaluated against experimental data from the NUPEC BWR Full-Size Fine-Mesh Bundle Tests (BFBT). The BFBT experiments utilized an 8 x 8 rod bundle to simulate BWR operating conditions and power profiles, providing an excellent database for investigation of the capabilities of the code. Benchmarks performed included steady-state and transient void distribution, single-phase and two-phase pressure drop, and steady-state and transient critical power measurements. COBRA-IE effectively captured the trends seen in the experimental data with acceptable prediction error. Future sensitivity studies are planned to investigate the effects of enabling and/or modifying optional code models dealing with void drift, turbulent mixing, rewetting, and CHF.
Date: April 26, 2006
Creator: Burns, C. J. and Aumiler, D. L.
System: The UNT Digital Library
DENSITY-FUNCTIONAL CALCULATIONS OF ALPHA-Pu-Ga (Al) ALLOYS (open access)

DENSITY-FUNCTIONAL CALCULATIONS OF ALPHA-Pu-Ga (Al) ALLOYS

None
Date: June 26, 2006
Creator: Landa, A; Soderlind, P & Vitos, L
System: The UNT Digital Library
B365 High Efficiency Particulate Air Filter Emergency Replacement An Example of Team Work (open access)

B365 High Efficiency Particulate Air Filter Emergency Replacement An Example of Team Work

None
Date: September 26, 2006
Creator: Coble, T; Little, C & Johnson, R
System: The UNT Digital Library
Proteomic Analysis of Calcium- and Phosphorylation-dependentCalmodulin Complexes in Mammalian Cells (open access)

Proteomic Analysis of Calcium- and Phosphorylation-dependentCalmodulin Complexes in Mammalian Cells

Protein conformational changes due to cofactor binding (e.g. metal ions, heme) and/or posttranslational modifications (e.g. phosphorylation) modulate dynamic protein complexes. Calmodulin (CaM) plays an essential role in regulating calcium (Ca{sup 2+}) signaling and homeostasis. No systematic approach on the identification of phosphorylation-dependent Ca{sup 2+}/CaM binding proteins has been published. Herein, we report a proteome-wide study of phosphorylation-dependent CaM binding proteins from mammalian cells. This method, termed 'Dynamic Phosphoprotein Complex Trapping', 'DPPC Trapping' for short, utilizes a combination of in vivo and in vitro assays. The basic strategy is to drastically shift the equilibrium towards endogenous phosphorylation of Ser, Thr, and Tyr at the global scale by inhibiting corresponding phosphatases in vivo. The phosphorylation-dependent calmodulin-binding proteins are then trapped in vitro in a Ca{sup 2+}-dependent manner by CaM-Sepharose chromatography. Finally, the isolated calmodulin-binding proteins are separated by SDS-PAGE and identified by LC/MS/MS. In parallel, the phosphorylation-dependent binding is visualized by silver staining and/or Western blotting. Using this method, we selectively identified over 120 CaM-associated proteins including many previously uncharacterized. We verified ubiquitin-protein ligase EDD1, inositol 1, 4, 5-triphosphate receptor type 1 (IP{sub 3}R1), and ATP-dependent RNA helicase DEAD box protein 3 (DDX3), as phosphorylation-dependent CaM binding proteins. To demonstrate the utilities …
Date: May 26, 2006
Creator: Jang, Deok-Jin & Wang, Daojing
System: The UNT Digital Library
Bulk Viscosity, Decaying Dark Matter, and the Cosmic Acceleration (open access)

Bulk Viscosity, Decaying Dark Matter, and the Cosmic Acceleration

The authors discuss a cosmology in which cold dark-matter particles decay into relativistic particles. They argue that such decays could lead naturally to a bulk viscosity in the cosmic fluid. for decay lifetimes comparable to the present hubble age, this bulk viscosity enters the cosmic energy equation as an effective negative pressure. They investigate whether this negative pressure is of sufficient magnitude to account for the observed cosmic acceleration. They show that a single decaying species in a {Lambda} = 0, flat, dark-matter dominated cosmology can not reproduce the observed magnitude-redshift relation from Type Ia supernovae. However, a delayed bulk viscosity, possibly due to a cascade of decaying particles may be able to account for a significant fraction of the apparent cosmic acceleration. Possible candidate nonrelativistic particles for this scenario include sterile neutrinos or gauge-mediated decaying supersymmetric particles.
Date: September 26, 2006
Creator: Wilson, J. R.; Mathews, G. & Fuller, G. M.
System: The UNT Digital Library
Evaluation of an Unsuccessful Brook Trout Electrofishing Removal Project in a Small Rocky Mountain Stream. (open access)

Evaluation of an Unsuccessful Brook Trout Electrofishing Removal Project in a Small Rocky Mountain Stream.

In the western United States, exotic brook trout Salvelinus fontinalis frequently have a deleterious effect on native salmonids, and biologists often attempt to remove brook trout from streams by means of electrofishing. Although the success of such projects typically is low, few studies have assessed the underlying mechanisms of failure, especially in terms of compensatory responses. A multiagency watershed advisory group (WAG) conducted a 3-year removal project to reduce brook trout and enhance native salmonids in 7.8 km of a southwestern Idaho stream. We evaluated the costs and success of their project in suppressing brook trout and looked for brook trout compensatory responses, such as decreased natural mortality, increased growth, increased fecundity at length, and earlier maturation. The total number of brook trout removed was 1,401 in 1998, 1,241 in 1999, and 890 in 2000; removal constituted an estimated 88% of the total number of brook trout in the stream in 1999 and 79% in 2000. Although abundance of age-1 and older brook trout declined slightly during and after the removals, abundance of age-0 brook trout increased 789% in the entire stream 2 years after the removals ceased. Total annual survival rate for age-2 and older brook trout did not …
Date: January 26, 2006
Creator: Meyer, Kevin A.; Lamansky, Jr., James A. & Schill, Daniel J.
System: The UNT Digital Library
Esimation of field-scale thermal conductivities of unsaturatedrocks from in-situ temperature data (open access)

Esimation of field-scale thermal conductivities of unsaturatedrocks from in-situ temperature data

A general approach is presented here which allows estimationof field-scale thermal properties of unsaturated rock using temperaturedata collected from in situ heater tests. The approach developed here isused to determine the thermal conductivities of the unsaturated host rockof the Drift Scale Test (DST) at Yucca Mountain, Nevada. The DST wasdesigned to obtain thermal, hydrological, mechanical, and chemical (THMC)data in the unsaturated fractured rock of Yucca Mountain. Sophisticatednumerical models have been developed to analyze these THMC data. However,though the objective of those models was to analyze "field-scale" (of theorder of tens-of-meters) THMC data, thermal conductivities measured from"laboratory-scale" core samples have been used as input parameters.While, in the absence of a better alternative, using laboratory-scalethermal conductivity values in field-scale models can be justified, suchapplications introduce uncertainties in the outcome of the models. Thetemperature data collected from the DST provides a unique opportunity toresolve some of these uncertainties. These temperature data can be usedto estimate the thermal conductivity of the DST host rock and, given thelarge volume of rock affected by heating at the DST, such an estimatewill be a more reliable effective thermal conductivity value for fieldscale application. In this paper, thus, temperature data from the DST areused to develop an estimate …
Date: June 26, 2006
Creator: Mukhopadhyay, Sumit; Tsang, Yvonne W. & Birkholzer, Jens T.
System: The UNT Digital Library
Photon Production through Multi-step Processes Important in Nuclear Fluorescence Experiments (open access)

Photon Production through Multi-step Processes Important in Nuclear Fluorescence Experiments

The authors present calculations describing the production of photons through multi-step processes occurring when a beam of gamma rays interacts with a macroscopic material. These processes involve the creation of energetic electrons through Compton scattering, photo-absorption and pair production, the subsequent scattering of these electrons, and the creation of energetic photons occurring as these electrons are slowed through Bremsstrahlung emission. Unlike single Compton collisions, during which an energetic photon that is scattered through a large angle loses most of its energy, these multi-step processes result in a sizable flux of energetic photons traveling at large angles relative to an incident photon beam. These multi-step processes are also a key background in experiments that measure nuclear resonance fluorescence by shining photons on a thin foil and observing the spectrum of back-scattered photons. Effective cross sections describing the production of backscattered photons are presented in a tabular form that allows simple estimates of backgrounds expected in a variety of experiments. Incident photons with energies between 0.5 MeV and 8 MeV are considered. These calculations of effective cross sections may be useful for those designing NRF experiments or systems that detect specific isotopes in well-shielded environments through observation of resonance fluorescence.
Date: October 26, 2006
Creator: Hagmann, C & Pruet, J
System: The UNT Digital Library
The Role of Nuclear Motion in the Photo-Double Ionization ofMolecular Hydrogen (open access)

The Role of Nuclear Motion in the Photo-Double Ionization ofMolecular Hydrogen

We examine the origin of recently observed variations with internuclear distance (R) of the fully differential cross sections for double ionization of aligned H2 by absorption of a single photon. Using the results of fully converged numerical solutions of the Schroedinger equation, we show that these variations arise primarily from pronounced differences in the R-dependence of the parallel and perpendicular components of the ionization amplitude. We also predict that R-dependences should be readily observable in the asymmetry parameter for photo-double ionization, even in experimental measurements that are not differential in the energy sharings between ejected photo-electrons.
Date: October 26, 2006
Creator: Horner, Daniel A.; Vanroose, Wim; Rescigno, Thomas N.; Martin,Fernando & McCurdy, C. William
System: The UNT Digital Library
Induced seismicity associated with enhanced geothermal system (open access)

Induced seismicity associated with enhanced geothermal system

Enhanced Geothermal Systems (EGS) offer the potential to significantly add to the world energy inventory. As with any development of new technology, some aspects of the technology has been accepted by the general public, but some have not yet been accepted and await further clarification before such acceptance is possible. One of the issues associated with EGS is the role of microseismicity during the creation of the underground reservoir and the subsequent extraction of the energy. The primary objectives of this white paper are to present an up-to-date review of the state of knowledge about induced seismicity during the creation and operation of enhanced geothermal systems, and to point out the gaps in knowledge that if addressed will allow an improved understanding of the mechanisms generating the events as well as serve as a basis to develop successful protocols for monitoring and addressing community issues associated with such induced seismicity. The information was collected though literature searches as well as convening three workshops to gather information from a wide audience. Although microseismicity has been associated with the development of production and injection operations in a variety of geothermal regions, there have been no or few adverse physical effects on the …
Date: September 26, 2006
Creator: Majer, Ernest; Majer, Ernest L.; Baria, Roy; Stark, Mitch; Oates, Stephen; Bommer, Julian et al.
System: The UNT Digital Library
Supersymmetry without the Desert (open access)

Supersymmetry without the Desert

Naturalness of electroweak symmetry breaking in weak scale supersymmetric theories may suggest the absence of the conventional supersymmetric desert. We present a simple, realistic framework for supersymmetry in which (most of) the virtues of the supersymmetric desert are naturally reproduced without having a large energy interval above the weak scale. The successful supersymmetric prediction for the low-energy gauge couplings is reproduced due to a gauged R symmetry present in the effective theory at the weak scale. The observable sector superpotential naturally takes the form of the next-to-minimal supersymmetric standard model, but without being subject to the Landau pole constraints up to the conventional unification scale. Supersymmetry breaking masses are generated by the F-term and D-term VEVs of singlet and U(1){sub R} gauge fields, as well as by anomaly mediation, at a scale not far above the weak scale. We study the resulting pattern of supersymmetry breaking masses in detail, and find that it can be quite distinct. We construct classes of explicit models within this framework, based on higher dimensional unified theories with TeV-sized extra dimensions. A similar model based on a non-R symmetry is also presented. These models have a rich phenomenology at the TeV scale, and allow for …
Date: September 26, 2006
Creator: Nomura, Yasunori & Poland, David
System: The UNT Digital Library
Commissioning of the Digital Transverse Bunch-by-Bunch Feedback System for the Tls. (open access)

Commissioning of the Digital Transverse Bunch-by-Bunch Feedback System for the Tls.

Multi-bunch instabilities degrade beam quality through increased beam emittance, energy spread and even beam loss. Feedback systems are used to suppress multi-bunch instabilities associated with the resistive wall of the beam ducts, cavity-like structures, and trapped ions. A new digital transverse bunch-by-bunch feedback system has recently been commissioned at the Taiwan Light Source, and has replaced the previous analog system. The new system has the advantages that it enlarges the tune acceptance and improves damping for transverse instability at high currents, such that top-up operation is achieved. After a coupled-bunch transverse instability was suppressed, more than 350 mA was successfully stored during preliminary commissioning. In this new system, a single feedback loop simultaneously suppresses both horizontal and vertical multi-bunch instabilities. Investigating the characteristics of the feedback loop and further improving the system performances are the next short-term goals. The feedback system employs the latest generation of field-programmable gate array (FPGA) processor to process bunch signals. Memory has been installed to capture up to 250 msec of bunch oscillation signal, considering system diagnostics suitable to support various beam physics studies.
Date: June 26, 2006
Creator: Hu, K. H.; Kuo, C. H.; Chou, P. J.; Lee, D.; Hsu, S. Y.; Chen, J. et al.
System: The UNT Digital Library
Detection of Ultra High Energy Neutrinos via Coherent Radio Emission (open access)

Detection of Ultra High Energy Neutrinos via Coherent Radio Emission

None
Date: May 26, 2006
Creator: Varner, G.; Gorham, P. W.; Kowalski, R. J.; Learned, J. G.; Link, J. T.; Matsuno, S. et al.
System: The UNT Digital Library
STATUS OF FAST IR ORBIT FEEDBACK AT RHIC. (open access)

STATUS OF FAST IR ORBIT FEEDBACK AT RHIC.

To compensate modulated beam-beam offsets caused by mechanical vibrations of IR triplet quadrupoles at frequencies around 10 Hz, a fast IR orbit feedback system has been developed. We report design considerations and recent status of the system.
Date: June 26, 2006
Creator: Montag, C.; Cupolo, J.; Glenn, J.; Litvinenko, V.; Marusic, A.; Meng, W. et al.
System: The UNT Digital Library
CHINA SPALLATION NEUTRON SOURCE ACCELERATORS: DESIGN, RESEARCH, AND DEVELOPMENT. (open access)

CHINA SPALLATION NEUTRON SOURCE ACCELERATORS: DESIGN, RESEARCH, AND DEVELOPMENT.

The China Spallation Neutron Source (CSNS) is a newly approved high-power accelerator project based on a H{sup -} linear accelerator and a rapid cycling synchrotron. During the past year, several major revisions were made on the design including the type of the front end, the linac frequency, the transport layout, the ring lattice, and the type of ring components. Here, we discuss the rationale of design revisions, status of the R&D efforts, and upgrade considerations.
Date: June 26, 2006
Creator: WEI, J.; FU, S. & FANG, S.
System: The UNT Digital Library
Equilibrium Beam Distribution in An Electron Storage Ring Near Linear Synchrobetatron Coupling Resonances (open access)

Equilibrium Beam Distribution in An Electron Storage Ring Near Linear Synchrobetatron Coupling Resonances

None
Date: May 26, 2006
Creator: Nash, B.; Wu, Ju-Hao & Chao, A.W.
System: The UNT Digital Library
A Non-Scaling FFAG for Rare Isotopes Production. (open access)

A Non-Scaling FFAG for Rare Isotopes Production.

This is a report to demonstrate use of Non-Scaling Fixed-Field Alternating-Gradient (FFAG) accelerators [1] in acceleration of partially stripped ions of Uranium-238 for Rare Isotopes Production. This example assumes a beam final energy of 500 MeV/u with an average beam output current of 1 {micro}A-particle and a beam average power of 120 kWatt.
Date: June 26, 2006
Creator: Ruggiero, A. G.; Roser, T. & Trbojevic, D.
System: The UNT Digital Library