Resource Type

Irony and the 'yoga wars' (open access)

Irony and the 'yoga wars'

Article discussing the debated topic of whether yoga is a Hindu or Secular practice and the potential causes and impacts of how and why this subject is being debated.
Date: December 2010
Creator: Jain, Pankaj
System: The UNT Digital Library
On the mechanism for plasma hydrogenation of graphene (open access)

On the mechanism for plasma hydrogenation of graphene

This article discusses the mechanism for plasma hydrogenation of graphene.
Date: December 6, 2010
Creator: Jones, Jason D.; Hoffmann, William D.; Jesseph, Aaron V.; Morris, Christopher; Verbeck, Guido F. & Pérez, José M.
System: The UNT Digital Library
A Two-Coordinate Nickel Imido Complex That Effects C-H Amination (open access)

A Two-Coordinate Nickel Imido Complex That Effects C-H Amination

This article discusses a two-coordinate nickel imido complex that effects C-H amination.
Date: December 22, 2010
Creator: Laskowski, Carl A.; Miller, Alexander J.M.; Hillhouse, Gregory L. & Cundari, Thomas R., 1964-
System: The UNT Digital Library
Temperature-dependent structural heterogeneity in calcium silicate liquids (open access)

Temperature-dependent structural heterogeneity in calcium silicate liquids

This article discusses temperature-dependent structural heterogeneity in calcium silicate liquids.
Date: December 7, 2010
Creator: Benmore, Chris J.; Weber, J. K. R.; Wilding, Martin C.; Du, Jincheng & Parise, John B.
System: The UNT Digital Library
Mutation of WRKY transcription factors initiates pith secondary wall formation and increases stem biomass in dicotyledonous plants (open access)

Mutation of WRKY transcription factors initiates pith secondary wall formation and increases stem biomass in dicotyledonous plants

Article discussing how the mutation of WRKY transcription factors initiates pith secondary wall formation and increases stem biomass in dicotyledonous plants.
Date: December 21, 2010
Creator: Wang, Huanzhong; Avci, Utku; Nakashima, Jin; Hahn, Michael G.; Chen, Fang & Dixon, R. A.
System: The UNT Digital Library
Advantages of a soft protective layer for good signal-to-noise ratio proton radiographs in high debris environments (open access)

Advantages of a soft protective layer for good signal-to-noise ratio proton radiographs in high debris environments

None
Date: December 21, 2010
Creator: Le Galloudec, N. R.; Cobble, J.; Nelson, S. L.; Merwin, A.; Paudel, Y.; Shrestha, I. et al.
System: The UNT Digital Library
Poroelastic response of orthotropic fractured porous media (open access)

Poroelastic response of orthotropic fractured porous media

An algorithm is presented for inverting either laboratory or field poroelastic data for all the drained constants of an anisotropic (specifically orthotropic) fractured poroelastic system. While fractures normally weaken the system by increasing the mechanical compliance, any liquids present in these fractures are expected to increase the stiffness somewhat, thus negating to some extent the mechanical weakening influence of the fractures themselves. The analysis presented quantifies these effects and shows that the key physical variable needed to account for the pore-fluid effects is a factor of (1 - B), where B is Skempton's second coe#14;fficient and satisfies 0 {<=} #20; B < 1. This scalar factor uniformly reduces the increase in compliance due to the presence of communicating fractures, thereby stiffening the fractured composite medium by a predictable amount. One further goal of the discussion is to determine how many of the poroelastic constants need to be known by other means in order to determine the rest from remote measurements, such as seismic wave propagation data in the field. Quantitative examples arising in the analysis show that, if the fracture aspect ratio a{sub f} ~ 0.1 and the pore fluid is liquid water, then for several cases considered Skempton's B …
Date: December 1, 2010
Creator: Berryman, J.G.
System: The UNT Digital Library
&quot;High Quantum Efficiency of Band-Edge Emission from ZnO Nanowires&quot; (open access)

&quot;High Quantum Efficiency of Band-Edge Emission from ZnO Nanowires&quot;

External quantum efficiency (EQE) of photoluminescence as high as 20 percent from isolated ZnO nanowires were measured at room temperature. The EQE was found to be highly dependent on photoexcitation density, which underscores the importance of uniform optical excitation during the EQE measurement. An integrating sphere coupled to a microscopic imaging system was used in this work, which enabled the EQE measurement on isolated ZnO nanowires. The EQE values obtained here are significantly higher than those reported for ZnO materials in forms of bulk, thin films or powders. Additional insight on the radiative extraction factor of one-dimensional nanostructures was gained by measuring the internal quantum efficiency of individual nanowires. Such quantitative EQE measurements provide a sensitive, noninvasive method to characterize the optical properties of low-dimensional nanostructures and allow tuning of synthesis parameters for optimization of nanoscale materials.
Date: December 1, 2010
Creator: Gargas, Daniel; Gao, Hanwei; Wang, Hungta & Peidong, Yang
System: The UNT Digital Library
Phased array compaction cell for measurement of the transversely isotropic elastic properties of compacting sediments (open access)

Phased array compaction cell for measurement of the transversely isotropic elastic properties of compacting sediments

Sediments undergoing compaction typically exhibit transversely isotropic (TI) elastic properties. We present a new experimental apparatus, the phased array compaction cell, for measuring the TI elastic properties of clay-rich sediments during compaction. This apparatus uses matched sets of P- and S-wave ultrasonic transducers located along the sides of the sample and an ultrasonic P-wave phased array source, together with a miniature P-wave receiver on the top and bottom ends of the sample. The phased array measurements are used to form plane P-waves that provide estimates of the phase velocities over a range of angles. From these measurements, the five TI elastic constants can be recovered as the sediment is compacted, without the need for sample unloading, recoring, or reorienting. This paper provides descriptions of the apparatus, the data processing, and an application demonstrating recovery of the evolving TI properties of a compacting marine sediment sample.
Date: December 15, 2010
Creator: Nihei, K.T.; Nakagawa, S.; Reverdy, F.; Meyer, L.R.; Duranti, L. & Ball, G.
System: The UNT Digital Library
Measurement of the atmospheric neutrino energy spectrum from 100 GeV to 400 TeV with IceCube (open access)

Measurement of the atmospheric neutrino energy spectrum from 100 GeV to 400 TeV with IceCube

None
Date: December 17, 2010
Creator: IceCube & etal, Abbasi, R,
System: The UNT Digital Library
Overview of Fusion-Fission Hybrid Blankets for Laser Inertial Fusion Energy (LIFE) Engine (open access)

Overview of Fusion-Fission Hybrid Blankets for Laser Inertial Fusion Energy (LIFE) Engine

None
Date: December 7, 2010
Creator: Kramer, K. J.; Fratoni, M.; Latkowski, J. F.; Abbott, R. P.; Havstad, M. A.; Anklam, T. M. et al.
System: The UNT Digital Library
Topology-based Feature Definition and Analysis (open access)

Topology-based Feature Definition and Analysis

Defining high-level features, detecting them, tracking them and deriving quantities based on them is an integral aspect of modern data analysis and visualization. In combustion simulations, for example, burning regions, which are characterized by high fuel-consumption, are a possible feature of interest. Detecting these regions makes it possible to derive statistics about their size and track them over time. However, features of interest in scientific simulations are extremely varied, making it challenging to develop cross-domain feature definitions. Topology-based techniques offer an extremely flexible means for general feature definitions and have proven useful in a variety of scientific domains. This paper will provide a brief introduction into topological structures like the contour tree and Morse-Smale complex and show how to apply them to define features in different science domains such as combustion. The overall goal is to provide an overview of these powerful techniques and start a discussion how these techniques can aid in the analysis of astrophysical simulations.
Date: December 10, 2010
Creator: Weber, Gunther H.; Bremer, Peer-Timo; Gyulassy, Attila & Pascucci, Valerio
System: The UNT Digital Library
Time-Integrated Searches for Point-like Sources of Neutrinos with the 40-String IceCube Detector (open access)

Time-Integrated Searches for Point-like Sources of Neutrinos with the 40-String IceCube Detector

None
Date: December 9, 2010
Creator: IceCube & etal, Abbasi, R,
System: The UNT Digital Library
Progress in Simulating Coulomb Collisions in Particle Codes (open access)

Progress in Simulating Coulomb Collisions in Particle Codes

A method for simulating Coulomb collisions in plasma simulations is described, in which particle weights are changed, instead of particle velocities.
Date: December 10, 2010
Creator: Hinton, F. L.; Yoon, E. S. & Chang, C. S.
System: The UNT Digital Library
Real-time high-resolution X-ray imaging and nuclear magnetic resonance study of the hydration of pure and Na-doped C3A in the presence of sulfates (open access)

Real-time high-resolution X-ray imaging and nuclear magnetic resonance study of the hydration of pure and Na-doped C3A in the presence of sulfates

This study details the differences in real-time hydration between pure tricalcium aluminate (cubic C{sub 3}A or 3CaO {center_dot} Al{sub 2}O{sub 3}) and Na-doped tricalcium aluminate (orthorhombic C{sub 3}A or Na{sub 2}Ca{sub 8}Al{sub 6}O{sub 18}), in aqueous solutions containing sulfate ions. Pure phases were synthesized in the laboratory to develop an independent benchmark for the reactions, meaning that their reactions during hydration in a simulated early age cement pore solution (saturated with respect to gypsum and lime) were able to be isolated. Because the rate of this reaction is extremely rapid, most microscopy methods are not adequate to study the early phases of the reactions in the early stages. Here, a high-resolution full-field soft X-ray imaging technique operating in the X-ray water window, combined with solution analysis by {sup 27}Al nuclear magnetic resonance (NMR) spectroscopy, was used to capture information regarding the mechanism of C{sub 3}A hydration during the early stages. There are differences in the hydration mechanism between the two types of C{sub 3}A, which are also dependent on the concentration of sulfate ions in the solution. The reactions with cubic C{sub 3}A (pure) seem to be more influenced by higher concentrations of sulfate ions, forming smaller ettringite needles at …
Date: December 1, 2010
Creator: Kirchheim, A. P.; Dal Molin, D. C.; Fischer, P.; Emwas, Abdul-Hamid; Provis, J. L. & Monteiro, P. J. M.
System: The UNT Digital Library
Charmed Hadron Physics at BABAR (open access)

Charmed Hadron Physics at BABAR

We present a study of the D{sup +}{pi}{sup -}, D{sup 0}{pi}{sup +}, and D*{sup +}{pi}{sup -} systems in inclusive e{sup +}e{sup -} {yields} c{bar c} interactions in a search for new excited D meson states. We use a dataset, consisting of {approx}454 fb{sup -1}, collected at center-of-mass energies near 10.58 GeV by the BABAR detector at the SLAC PEP-II asymmetric-energy collider. We observe, for the first time, candidates for the radial excitations of the D{sup 0}, D*{sup 0}, and D*{sup +}, as well as the L = 2 excited states of the D{sup 0} and D{sup +}, where L is the orbital angular momentum of the quarks.
Date: December 16, 2010
Creator: Benitez, Jose
System: The UNT Digital Library
Using a two-step matrix solution to reduce the run time in KULL's magnetic diffusion package (open access)

Using a two-step matrix solution to reduce the run time in KULL's magnetic diffusion package

Recently a Resistive Magnetohydrodynamics (MHD) package has been added to the KULL code. In order to be compatible with the underlying hydrodynamics algorithm, a new sub-zonal magnetics discretization was developed that supports arbitrary polygonal and polyhedral zones. This flexibility comes at the cost of many more unknowns per zone - approximately ten times more for a hexahedral mesh. We can eliminate some (or all, depending on the dimensionality) of the extra unknowns from the global matrix during assembly by using a Schur complement approach. This trades expensive global work for cache-friendly local work, while still allowing solution for the full system. Significant improvements in the solution time are observed for several test problems.
Date: December 17, 2010
Creator: Brunner, T A & Kolev, T V
System: The UNT Digital Library
The use of a high-order MEMS deformable mirror in the Gemini Planet Imager (open access)

The use of a high-order MEMS deformable mirror in the Gemini Planet Imager

We briefly review the development history of the Gemini Planet Imager's 4K Boston Micromachines MEMS deformable mirror. We discuss essential calibration steps and algorithms to control the MEMS with nanometer precision, including voltage-phase calibration and influence function characterization. We discuss the integration of the MEMS into GPI's Adaptive Optics system at Lawrence Livermore and present experimental results of 1.5 kHz closed-loop control. We detail mitigation strategies in the coronagraph to reduce the impact of abnormal actuators on final image contrast.
Date: December 17, 2010
Creator: Poyneer, L. A.; Bauman, B.; Cornelissen, S.; Jones, S.; Macintosh, B.; Palmer, D. et al.
System: The UNT Digital Library
The National Ignition Facility and the Promise of Inertial Fusion Energy (open access)

The National Ignition Facility and the Promise of Inertial Fusion Energy

The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory (LLNL) in Livermore, CA, is now operational. The NIF is the world's most energetic laser system capable of producing 1.8 MJ and 500 TW of ultraviolet light. By concentrating the energy from its 192 extremely energetic laser beams into a mm{sup 3}-sized target, NIF can produce temperatures above 100 million K, densities of 1,000 g/cm{sup 3}, and pressures 100 billion times atmospheric pressure - conditions that have never been created in a laboratory and emulate those in planetary interiors and stellar environments. On September 29, 2010, the first integrated ignition experiment was conducted, demonstrating the successful coordination of the laser, cryogenic target system, array of diagnostics and infrastructure required for ignition demonstration. In light of this strong progress, the U.S. and international communities are examining the implication of NIF ignition for inertial fusion energy (IFE). A laser-based IFE power plant will require a repetition rate of 10-20 Hz and a laser with 10% electrical-optical efficiency, as well as further development and advances in large-scale target fabrication, target injection, and other supporting technologies. These capabilities could lead to a prototype IFE demonstration plant in the 10- to 15-year time frame. …
Date: December 13, 2010
Creator: Moses, E I
System: The UNT Digital Library
INSTALLATION OF BUBBLERS IN THE SAVANNAH RIVER SITED DEFENSE WASTE PROCESSING FACILITY MELTER (open access)

INSTALLATION OF BUBBLERS IN THE SAVANNAH RIVER SITED DEFENSE WASTE PROCESSING FACILITY MELTER

Savannah River Remediation (SRR) LLC assumed the liquid waste contract at the Savannah River Site (SRS) in the summer of 2009. The main contractual agreement was to close 22 High Level Waste (HLW) tanks in eight years. To achieve this aggressive commitment, faster waste processing throughout the SRS liquid waste facilities will be required. Part of the approach to achieve faster waste processing is to increase the canister production rate of the Defense Waste Processing Facility (DWPF) from approximately 200 canisters filled with radioactive waste glass per year to 400 canisters per year. To reach this rate for melter throughput, four bubblers were installed in the DWPF Melter in the late summer of 2010. This effort required collaboration between SRR, SRR critical subcontractor EnergySolutions, and Savannah River Nuclear Solutions, including the Savannah River National Laboratory (SRNL). The tasks included design and fabrication of the bubblers and related equipment, testing of the bubblers for various technical issues, the actual installation of the bubblers and related equipment, and the initial successful operation of the bubblers in the DWPF Melter.
Date: December 8, 2010
Creator: Smith, M. & Iverson, D.
System: The UNT Digital Library
Summary of session 3 on synchrotron radiation and beam dynamics (open access)

Summary of session 3 on synchrotron radiation and beam dynamics

We summarize presentations, discussions and general conclusions of the Workshop session on 'Beam Dynamics Issues'. Major subjects include effects due to synchrotron radiation (SR), cryogenic loads, electron cloud, impedances, intra-beam scattering (IBS) and beam-beam interactions.
Date: December 1, 2010
Creator: Shiltsev, V. & Metral, E.
System: The UNT Digital Library
Adjoint-Based Implicit Uncertainty Analysis for Figures of Merit in a Laser Inertial Fusion Engine (open access)

Adjoint-Based Implicit Uncertainty Analysis for Figures of Merit in a Laser Inertial Fusion Engine

A primary purpose of computational models is to inform design decisions and, in order to make those decisions reliably, the confidence in the results of such models must be estimated. Monte Carlo neutron transport models are common tools for reactor designers. These types of models contain several sources of uncertainty that propagate onto the model predictions. Two uncertainties worthy of note are (1) experimental and evaluation uncertainties of nuclear data that inform all neutron transport models and (2) statistical counting precision, which all results of a Monte Carlo codes contain. Adjoint-based implicit uncertainty analyses allow for the consideration of any number of uncertain input quantities and their effects upon the confidence of figures of merit with only a handful of forward and adjoint transport calculations. When considering a rich set of uncertain inputs, adjoint-based methods remain hundreds of times more computationally efficient than Direct Monte-Carlo methods. The LIFE (Laser Inertial Fusion Energy) engine is a concept being developed at Lawrence Livermore National Laboratory. Various options exist for the LIFE blanket, depending on the mission of the design. The depleted uranium hybrid LIFE blanket design strives to close the fission fuel cycle without enrichment or reprocessing, while simultaneously achieving high discharge …
Date: December 3, 2010
Creator: Seifried, J. E.; Fratoni, M.; Kramer, K. J.; Latkowski, J. F.; Peterson, P. F.; Powers, J. J. et al.
System: The UNT Digital Library
Solid State NMR Investigations of Chain Dynamics and Network Order in Model Poly(dimethylsiloxane) Elastomers (open access)

Solid State NMR Investigations of Chain Dynamics and Network Order in Model Poly(dimethylsiloxane) Elastomers

This work is at a relatively early stage, however it has been demonstrated that we can reliably probe basic network architectures using the MQ-NMR technique. The initial results are in good agreement with what is known from standard network theory and will serve as a basis for the study of progressively increasing structural complexity in Siloxane network systems.
Date: December 9, 2010
Creator: Lewicki, J P; Mayer, B P; Wilson, T S; Chinn, S C & Maxwell, R S
System: The UNT Digital Library
Experimental Study of High-Z Gas Buffers in Gas-Filled ICF Engines (open access)

Experimental Study of High-Z Gas Buffers in Gas-Filled ICF Engines

ICF power plants, such as the LIFE scheme at LLNL, may employ a high-Z, target-chamber gas-fill to moderate the first-wall heat-pulse due to x-rays and energetic ions released during target detonation. To reduce the uncertainties of cooling and beam/target propagation through such gas-filled chambers, we present a pulsed plasma source producing 2-5 eV plasma comprised of high-Z gases. We use a 5-kJ, 100-ns theta discharge for high peak plasma-heating-power, an electrode-less discharge for minimizing impurities, and unobstructed axial access for diagnostics and beam (and/or target) propagation studies. We will report on the plasma source requirements, design process, and the system design.
Date: December 3, 2010
Creator: Rhodes, M A; Kane, J; Loosmore, G; DeMuth, J & Latkowski, J
System: The UNT Digital Library