States

Final Progress Report: Developing Ethical Practices for Genetics Testing in the Workplace (open access)

Final Progress Report: Developing Ethical Practices for Genetics Testing in the Workplace

Our multidisciplinary research team for this project involved collaboration between the Department of Psychiatry and Behavioral Medicine at the Medical College of Wisconsin (MCW) and the Department of Family and Community Medicine at the University of New Mexico Health Sciences Center (UNM HSC). Our research team in Wisconsin was led by Laura Roberts, M.D., Principal Investigator, and included Scott Helberg, MLS (Project Coordinator), Kate Green Hammond, Ph.D. (Consultant), Krisy Edenharder (Research Coordinator), and Mark Talatzko (Research Assistant). Our New Mexico-based team was led by Teddy Warner, Ph.D., Co-Principal Investigator and UNM Site Principal Investigator, and included Suzanne Roybal (Project Assistant), Darlyn Mabon (Project Assistant), Kate Green Hammond, PhD (Senior Research Scientist on the UNM team from 2004 until January, 2007), and Paulette Christopher (Research Assistant). In addition, computer technical and web support for the web-based survey conducted on a secure server at the University of New Mexico was provided by Kevin Wiley and Kim Hagen of the Systems and Programming Team of the Health Sciences Center Library and Information Center. We stated 3 aims in the grant proposal: (1) To collect web survey reports of the ethical perspectives, concerns, preferences and decision-making related to genetic testing using surveys from employees …
Date: May 14, 2008
Creator: Roberts, Laura & Warner, Teddy
Object Type: Text
System: The UNT Digital Library
A Methodology to Measure Synergy Among Energy-Efficiency Programs at the Program Participant Level (open access)

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

This paper presents a methodology designed to measure synergy among energy-efficiency programs at the program participant level (e.g., households, firms). Three different definitions of synergy are provided: strong, moderate, and weak. Data to measure synergy can be collected through simple survey questions. Straightforward mathematical techniques can be used to estimate the three types of synergy and explore relative synergistic impacts of different subsets of programs. Empirical research is needed to test the concepts and methods and to establish quantitative expectations about synergistic relationships among programs. The market for new energy-efficient motors is the context used to illustrate all the concepts and methods in this paper.
Date: November 14, 2003
Creator: Tonn, B.E.
Object Type: Report
System: The UNT Digital Library
Development of a large aperture Nb3Sn racetrack quadrupolemagnet (open access)

Development of a large aperture Nb3Sn racetrack quadrupolemagnet

The U.S. LHC Accelerator Research Program (LARP), a collaboration between BNL, FNAL, LBNL, and SLAC, has among its major objectives the development of advanced magnet technology for an LHC luminosity upgrade. The LBNL Superconducting Magnet Group supports this program with a broad effort involving design studies, Nb{sub 3}Sn conductor development, mechanical models, and basic prototypes. This paper describes the development of a large aperture Nb{sub 3}Sn racetrack quadrupole magnet using four racetrack coils from the LBNL Subscale Magnet (SM) Program. The magnet provides a gradient of 95 T/m in a 110 mm bore, with a peak field in the conductor of 11.2 T. The coils are prestressed by a mechanical structure based on a pre-tensioned aluminum shell, and axially supported with aluminum rods. The mechanical behavior has been monitored with strain gauges and the magnetic field has been measured. Results of the test are reported and analyzed.
Date: April 14, 2005
Creator: Ferracin, Paolo; Bartlett, Scott E.; Caspi, Shlomo; Dietderich,Daniel R.; Gourlay, Steven A.; Hannaford, Charles R. et al.
Object Type: Article
System: The UNT Digital Library
Modeling the Cathodic Region in Crevice Corrosion Under a Thin Electrolyte Film Including Particulates (open access)

Modeling the Cathodic Region in Crevice Corrosion Under a Thin Electrolyte Film Including Particulates

Crevice corrosion may be limited by the capacity of the external cathodic region to support anodic dissolution currents within the crevice. The analysis here focuses on behavior of metal surfaces covered by a thin ({approx}microns) layer of the electrolyte film including particulates. The particulates can affect the cathode current capacity (I{sub total}) by increasing the solution resistance (''volume effect'') and by decreasing the electrode area (''surface effect''). In addition, there can be particulate effects on oxygen reduction kinetics and oxygen transport. This work simulates and characterizes the effect of a uniform particulate monolayer on the cathode current capacity for steady state conditions in the presence of a thin electrolyte film. Particulate configurations with varying particle size, shape, arrangement, volume fraction, and electrode area coverage were numerically modeled as a function of the properties of the system. It is observed that the effects of particles can be fully accounted for in terms of two corrections: the volume blockage effect on the electrolyte resistivity can be correlated using Bruggeman's equation, and the electrode coverage effect can be modeled in terms of a simple area correction to the kinetics expression. For the range of parameters analyzed, applying these two correction factors, cathodes covered …
Date: March 14, 2006
Creator: Agarwal, A. S.; Landau, U.; Shan, X. & Payer, J. H.
Object Type: Report
System: The UNT Digital Library
Molecular Dynamics Simulations of Temperature Equilibration in Dense Hydrogen (open access)

Molecular Dynamics Simulations of Temperature Equilibration in Dense Hydrogen

The temperature equilibration rate in dense hydrogen (for both T{sub i} > T{sub e} and T{sub i} < T{sub e}) has been calculated with large-scale molecular dynamics simulations for temperatures between 10 and 300 eV and densities between 10{sup 20}/cc to 10{sup 24}/cc. Careful attention has been devoted to convergence of the simulations, including the role of semiclassical potentials. We find that for Coulomb logarithms L {approx}> 1, Brown-Preston-Singleton [Brown et al., Phys. Rep. 410, 237 (2005)] with the sub-leading corrections and the fit of Gericke-Murillo-Schlanges [Gericke et al., PRE 65, 036418 (2003)] to the T-matrix evaluation of the collision operator, agrees with the MD data to within the error bars of the simulation. For more strongly-coupled plasmas where L {approx}< 1, our numerical results are consistent with the fit of Gericke-Murillo-Schlanges.
Date: February 14, 2008
Creator: Glosli, J; Graziani, F; More, R; Murillo, M; Streitz, F; Surh, M et al.
Object Type: Article
System: The UNT Digital Library
Imaging of InGaN inhomogeneities using visible aperturelessnear-field scanning optical microscope (open access)

Imaging of InGaN inhomogeneities using visible aperturelessnear-field scanning optical microscope

The optical properties of epitaxially grown islands of InGaN are investigated with nanometer-scale spatial resolution using visible apertureless near-field scanning optical microscopy. Scattered light from the tip-sample system is modulated by cantilever oscillations and detected at the third harmonic of the oscillation frequency to distinguish the near-field signal from unwanted scattered background light. Scattered near-field measurements indicate that the as-grown InGaN islanded film may exhibit both inhomogeneous In composition and strain-induced changes that affect the optical signal at 633 nm and 532 nm. Changes are observed in the optical contrast for large 3D InGaN islands (100's of nm) of the same height. Near-field optical mapping of small grains on a finer scale reveals InGaN composition or strain-induced irregularities in features with heights of only 2 nm, which exhibit different near-field signals at 633 nm and 532 nm incident wavelengths. Optical signal contrast from topographic features as small as 30 nm is detected.
Date: June 14, 2007
Creator: Stebounova, Larissa V.; Romanyuk, Yaroslav E.; Chen, Dongxue & Leone, Stephen R.
Object Type: Article
System: The UNT Digital Library
A Collapse Surface for Perforated Plates with Triangular Patterns for Ligament Efficiencies Between 0.05 and 0.50 (open access)

A Collapse Surface for Perforated Plates with Triangular Patterns for Ligament Efficiencies Between 0.05 and 0.50

Collapse surfaces are developed for thick perforated plates containing a triangular penetration pattern with ligament efficiencies of 0.05, 0.10, 0.15, 0.2, 0.3, and 0.5 using elastic-perfectly plastic FEA analysis. The FEA data was fit to a fourth-order collapse function which is appropriate for the development of an equivalent solid elastic-perfectly plastic plasticity model for perforated plates with triangular penetration patterns. This type of model can be conveniently used to develop a limit load capability for perforated plate analysis. It was shown that the fourth-order function is reasonable for ligament efficiencies between 0.15 to 0.5. Comparing the fourth-order collapse function to FEA data suggests that an alternate collapse function is needed for ligament efficiencies less than 0.15. A linear interpolation method was shown to be appropriate for ligament efficiencies between 0.15 and 0.5.
Date: December 14, 2000
Creator: Gordon, D.P. Jones and J.L.
Object Type: Report
System: The UNT Digital Library
Cost-Effective Integration of Efficient Low-Lift Base Load Cooling Equipment (open access)

Cost-Effective Integration of Efficient Low-Lift Base Load Cooling Equipment

The long-term goal of DOE’s Commercial Buildings Integration subprogram is to develop cost-effective technologies and building practices that will enable the design and construction of net Zero Energy Buildings — commercial buildings that produce as much energy as they use on an annual basis — by 2025. To support this long-term goal, DOE further called for — as part of its FY07 Statement of Needs — the development by 2010 of “five cost-effective design technology option sets using highly efficient component technologies, integrated controls, improved construction practices, streamlined commissioning, maintenance and operating procedures that will make new and existing commercial buildings durable, healthy and safe for occupants.” In response, PNNL proposed and DOE funded a scoping study investigation of one such technology option set, low-lift cooling, that offers potentially exemplary HVAC energy performance relative to ASHRAE Standard 90.1-2004. The primary purpose of the scoping study was to estimate the national technical energy savings potential of this TOS.
Date: January 14, 2008
Creator: Jiang, Wei; Winiarski, David W.; Katipamula, Srinivas & Armstrong, Peter R.
Object Type: Report
System: The UNT Digital Library
Direct Observation of Cosmic Strings Via Their Strong Gravitational Lensing Effect. 1. Predictions for High Resolution Imaging Surveys (open access)

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

We use current theoretical estimates for the density of long cosmic strings to predict the number of strong gravitational lensing events in astronomical imaging surveys as a function of angular resolution and survey area. We show that angular resolution is the single most important factor, and that interesting limits on the dimensionless string tension G{mu}/c{sup 2} can be obtained by existing and planned surveys. At the resolution of the Hubble Space Telescope (0'.14), it is sufficient to survey of order a square degree -- well within reach of the current HST archive -- to probe the regime G{mu}/c{sup 2} {approx} 10{sup -8}. If lensing by cosmic strings is not detected, such a survey would improve the limit on the string tension by an order of magnitude on that available from the cosmic microwave background. At the resolution (0'.028) attainable with the next generation of large ground based instruments, both in the radio and the infra-red with adaptive optics, surveying a sky area of order ten square degrees will allow us to probe the G{mu}/c{sup 2} {approx} 10{sup -9} regime. These limits will not be improved significantly by increasing the solid angle of the survey.
Date: November 14, 2007
Creator: Gasparini, Maria Alice; Marshall, Phil; Treu, Tommaso; /UC, Santa Barbara; Morganson, Eric; /KIPAC, Menlo Park et al.
Object Type: Article
System: The UNT Digital Library
Hydrologic Data and Evaluation for Model Validation Wells, MV-1, MV-2, and MV-3 near the Project Shoal Area (open access)

Hydrologic Data and Evaluation for Model Validation Wells, MV-1, MV-2, and MV-3 near the Project Shoal Area

In 2006, a drilling campaign was conducted at the Project Shoal Area (PSA) to provide information for model validation, emplace long-term monitoring wells, and develop baseline geochemistry for long term hydrologic monitoring. Water levels were monitored in the vicinity of the drilling, in the existing wells HC-1 and HC-6, as well as in the newly drilled wells, MV-1, MV-2 and MV-3 and their associated piezometers. Periodic water level measurements were also made in existing wells HC-2, HC-3, HC-4, HC-5 and HC-7. A lithium bromide chemical tracer was added to drilling fluids during the installation of the monitoring and validation (MV) wells and piezometers. The zones of interest were the fractured, jointed and faulted horizons within a granitic body. These horizons generally have moderate hydraulic conductivities. As a result, the wells and their shallower piezometers required strenuous purging and development to remove introduced drilling fluids as evidenced by bromide concentrations. After airlift and surging well development procedures, the wells were pumped continuously until the bromide concentration was less then 1 milligram per liter (mg/L). Water quality samples were collected after the well development was completed. Tritium scans were preformed before other analyses to ensure the absence of high levels of radioactivity. …
Date: February 14, 2007
Creator: Lyles, B.; Oberlander, P.; Gillespie, D.; Donithan, D.; Chapman, J. & Healey, J.
Object Type: Report
System: The UNT Digital Library
In –Situ Spectroscopic Investigation of Immobilized Organometallic Catalysts (open access)

In –Situ Spectroscopic Investigation of Immobilized Organometallic Catalysts

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

BLACKFEET NATION FIRST STEPS TO RENEWABLE ENERGY – ENERGY ORGANIZATION DEVELOPMENT PROJECT FINAL REPORT

The Blackfeet Nation Energy Organization Development project, which was funded through the auspices of the Department of Energy First Steps to Renewable Energy Grant, has produced a centralized effort that assists the Blackfeet Tribal Business Council in the proper management, development, and informed decision making ability to negotiate and develop Blackfeet Renewable Energy opportunities, with a special emphasis on wind energy development. In addition, the Blackfeet Nation has been armed with an enhanced ability to examine environmental and legal issues, perform market research, identify additional lands for possible acquisition and development, and examine wind energy projects by other tribes that serve as models. The product of this effort has been that the Blackfeet Nation formerly petitioned the Bureau of Indian Affairs to approve and charter an Indian Reorganization Act, Section 17 Corporation, the Blackfeet Renewable Energy Inc. Please See Attachment.
Date: May 14, 2008
Creator: Lawrence, Jeri
Object Type: Report
System: The UNT Digital Library
Chromosomal mosaicism in mouse two-cell embryos after paternal exposure to acrylamide (open access)

Chromosomal mosaicism in mouse two-cell embryos after paternal exposure to acrylamide

Chromosomal mosaicism in human preimplantation embryos is a common cause ofspontaneous abortions, however, our knowledge of its etiology is limited. We used multicolor fluorescence in situ hybridization (FISH) painting to investigate whether paternally-transmitted chromosomal aberrations result in mosaicism in mouse 2-cell embryos. Paternal exposure to acrylamide, an important industrial chemical also found in tobacco smoke and generated during the cooking process of starchy foods, produced significant increases in chromosomally defective 2-cell embryos, however, the effects were transient primarily affecting the postmeiotic stages of spermatogenesis. Comparisons with our previous study of zygotes demonstrated similar frequencies of chromosomally abnormal zygotes and 2-cell embryos suggesting that there was no apparent selection against numerical or structural chromosomal aberrations. However, the majority of affected 2-cell embryos were mosaics showing different chromosomal abnormalities in the two blastomeric metaphases. Analyses of chromosomal aberrations in zygotes and 2-cell embryos showed a tendency for loss of acentric fragments during the first mitotic division ofembryogenesis, while both dicentrics and translocations apparently underwent propersegregation. These results suggest that embryonic development can proceed up to the end of the second cell cycle of development in the presence of abnormal paternal chromosomes and that even dicentrics can persist through cell division. The high …
Date: October 14, 2008
Creator: Marchetti, Francesco; Bishop, Jack; Lowe, Xiu & Wyrobek, Andrew J
Object Type: Article
System: The UNT Digital Library
Exact seismic velocities for VTI and HTI media and extendedThomsen Formulas for stronger anisotropies (open access)

Exact seismic velocities for VTI and HTI media and extendedThomsen Formulas for stronger anisotropies

I explore a different type of approximation to the exactanisotropic wave velocities as a function of incidence angle invertically transversely isotropic (VTI) media. This method extends theThomsen weak anisotropy approach to stronger anisotropy withoutsignificantly affecting the simplicity of the formulas. One importantimprovement is that the peak of the quasi-SV-wave speed vsv(theta) islocated at the correct incidence angle theta= theta max, rather thanalways being at the position theta = 45o, which universally holds forThomsen's approximation although max theta = 45o is actually nevercorrect for any VTI anisotropic medium. The magnitudes of all the wavespeeds are also more closely approximated for all values of the incidenceangle. Furthermore, the value of theta max (which is needed in the newformulas) can be deduced from the same data that are typically used inthe weak anisotropy data analysis. The two examples presented are basedon systems having vertical fractures. The first set of model fractureshas their axes of symmetry randomly oriented in the horizontal plane.Such a system is then isotropic in the horizontal plane and, therefore,exhibits vertical transverse isotropic (VTI) symmetry. The second set offractures also has axes of symmetry in the horizontal plane, but it isassumed these axes are aligned so that the system exhibits horizontaltransverse …
Date: May 14, 2007
Creator: Berryman, J.G.
Object Type: Article
System: The UNT Digital Library
Scaling Behavior of Barkhausen Avalanches along the Hysteresis loop in Nucleation-Mediated Magnetization Reversal Process (open access)

Scaling Behavior of Barkhausen Avalanches along the Hysteresis loop in Nucleation-Mediated Magnetization Reversal Process

We report the scaling behavior of Barkhausen avalanches for every small field step along the hysteresis loop in CoCrPt alloy film having perpendicular magnetic anisotropy. Individual Barkhausen avalanche is directly observed utilizing a high-resolution soft X-ray microscopy that provides real space images with a spatial resolution of 15 nm. Barkhausen avalanches are found to exhibit power-law scaling behavior at all field steps along the hysteresis loop, despite their different patterns for each field step. Surprisingly, the scaling exponent of the power-law distribution of Barkhausen avalanches is abruptly altered from 1 {+-} 0.04 to 1.47 {+-} 0.03 as the field step is close to the coercive field. The contribution of coupling among adjacent domains to Barkhausen avalanche process affects the sudden change of the scaling behavior observed at the coercivity-field region on the hysteresis loop of CoCrPt alloy film.
Date: October 14, 2008
Creator: Im, Mi-Young; Fischer, Peter; Kim, D.-H. & Shin, S.-C.
Object Type: Article
System: The UNT Digital Library
AGN-Induced Cavities in NGC 1399 And NGC 4649 (open access)

AGN-Induced Cavities in NGC 1399 And NGC 4649

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

An Implementation and Evaluation of the AMLS Method for SparseEigenvalue Problems

We describe an efficient implementation and present aperformance study of an algebraic multilevel sub-structuring (AMLS)method for sparse eigenvalue problems. We assess the time and memoryrequirements associated with the key steps of the algorithm, and compareitwith the shift-and-invert Lanczos algorithm in computational cost. Oureigenvalue problems come from two very different application areas: theaccelerator cavity design and the normal mode vibrational analysis of thepolyethylene particles. We show that the AMLS method, when implementedcarefully, is very competitive with the traditional method in broadapplication areas, especially when large numbers of eigenvalues aresought.
Date: February 14, 2006
Creator: Gao, Weiguo; Li, Xiaoye S.; Yang, Chao & Bai, Zhaojun
Object Type: Article
System: The UNT Digital Library
Adversary Modeling for Allocation of Effort Across Countermeasures (open access)

Adversary Modeling for Allocation of Effort Across Countermeasures

None
Date: July 14, 2006
Creator: Lathrop, J F
Object Type: Article
System: The UNT Digital Library
UNIT CURIE DOSE EVALUATION (open access)

UNIT CURIE DOSE EVALUATION

The development of radiological consequence lookup tables for postulated releases of radionuclides commonly used at Savannah River Site (SRS) and other Department of Energy (DOE) facilities requires the use of the MELCOR Accident Consequence Code System (MACCS)/MACCS2. MACCS2 users input site-specific data: such as stack or ground release, building wake effects, boundary distance from release source, and site-specific meteorological data. MACCS2 also allows the input of more general data such as plume rise and wet and/or dry deposition. The acceptance of such inputs gives the MACCS2 program a broad spectrum of uses at participating DOE facilities. The MACCS2 outputs are converted to an excel spreadsheet to facilitate fast and accurate results for various accident scenarios. Consequence lookup tables can be employed to determine the effects of radiological accident scenarios before they occur. The data is then used by DOE facilities to create regulations and controls to prepare for worst-case scenarios.
Date: April 14, 2008
Creator: Hang, P
Object Type: Article
System: The UNT Digital Library
ELECTROCHEMICAL CORROSION TESTS FOR TANK 241-AY-101 CORE 325 SEGMENTS 16R1 & 16R2 (open access)

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

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

Measurements and Phenomenological Modeling of Magnetic FluxBuildup in Spheromak Plasmas

Internal magnetic field measurements and high-speed imaging at the Sustained Spheromak Physics Experiment (SSPX) [E. B. Hooper, L. D. Pearlstein, R. H. Bulmer, Nucl. Fusion 39, 863 (1999)] are used to study spheromak formation and field buildup. The measurements are analyzed in the context of a phenomenological model of magnetic helicity based on the topological constraint of minimum helicity in the open flux before reconnecting and linking closed flux. Two stages are analyzed: (1) the initial spheromak formation, i. e. when all flux surfaces are initially open and reconnect to form open and closed flux surfaces, and (2) the stepwise increase of closed flux when operating the gun on a new mode that can apply a train of high-current pulses to the plasma. In the first stage, large kinks in the open flux surfaces are observed in the high-speed images taken shortly after plasma breakdown, and coincide with large magnetic asymmetries recorded in a fixed insertable magnetic probe that spans the flux conserver radius. Closed flux (in the toroidal average sense) appears shortly after this. This stage is also investigated using resistive magnetohydrodynamic simulations. In the second stage, a time lag in response between open and closed flux surfaces after …
Date: December 14, 2007
Creator: Romero-Talamas, C. A.; Hooper, E. B.; Jayakumar, R.; McLean, H. S.; Wood, R. D. & Moller, J. M.
Object Type: Article
System: The UNT Digital Library
VHE Gamma-Rays From Westerlund 2 And Implications for the Inferred Energetics (open access)

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

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

HANFORD DOUBLE SHELL TANK THERMAL AND SEISMIC PROJECT BUCKLING EVALUATION METHODS AND RESULTS FOR THE PRIMARY TANKS

This report documents a detailed buckling evaluation of the primary tanks in the Hanford double-shell waste tanks (DSTs), which is part of a comprehensive structural review for the Double-Shell Tank Integrity Project. This work also provides information on tank integrity that specifically responds to concerns raised by the Office of Environment, Safety, and Health (ES&H) Oversight (EH-22) during a review of work performed on the double-shell tank farms and the operation of the aging waste facility (AWF) primary tank ventilation system. The current buckling review focuses on the following tasks: (1) Evaluate the potential for progressive anchor bolt failure and the appropriateness of the safety factors that were used for evaluating local and global buckling. The analysis will specifically answer the following questions: (a) Can the EH-22 scenario develop if the vacuum is limited to -6.6-inch water gage (w.g.) by a relief valve? (b) What is the appropriate factor of safety required to protect against buckling if the EH-22 scenario can develop? (c) What is the appropriate factor of safety required to protect against buckling if the EH-22 scenario cannot develop? (2) Develop influence functions to estimate the axial stresses in the primary tanks for all reasonable combinations of tank …
Date: January 14, 2009
Creator: TC, MACKEY; KI, JOHNSON; JE, DEIBLER; SP, PILLI; MW, RINKER & NK, KARRI
Object Type: Report
System: The UNT Digital Library
Insertion of a self-splicing intron into the mtDNA of atriploblastic animal (open access)

Insertion of a self-splicing intron into the mtDNA of atriploblastic animal

Nephtys longosetosa is a carnivorous polychaete worm that lives in the intertidal and subtidal zones with worldwide distribution (pleijel&rouse2001). Its mitochondrial genome has the characteristics typical of most metazoans: 37 genes; circular molecule; almost no intergenic sequence; and no significant gene rearrangements when compared to other annelid mtDNAs (booremoritz19981995). Ubiquitous features as small intergenic regions and lack of introns suggested that metazoan mtDNAs are under strong selective pressures to reduce their genome size allowing for faster replication requirements (booremoritz19981995Lynch2005). Yet, in 1996 two type I introns were found in the mtDNA of the basal metazoan Metridium senile (FigureX). Breaking a long-standing rule (absence of introns in metazoan mtDNA), this finding was later supported by the further presence of group I introns in other cnidarians. Interestingly, only the class Anthozoa within cnidarians seems to harbor such introns. Although several hundreds of triploblastic metazoan mtDNAs have been sequenced, this study is the first evidence of mitochondrial introns in triploblastic metazoans. The cox1 gene of N. longosetosa has an intron of almost 2 kbs in length. This finding represents as well the first instance of a group II intron (anthozoans harbor group I introns) in all metazoan lineages. Opposite trends are observed within …
Date: April 14, 2006
Creator: Valles, Y.; Halanych, K. & Boore, J.L.
Object Type: Article
System: The UNT Digital Library