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A Piecewise Bi-Linear Discontinuous Finite Element Spatial Discretization of the Sn Transport Equation (open access)

A Piecewise Bi-Linear Discontinuous Finite Element Spatial Discretization of the Sn Transport Equation

We present a new spatial discretization of the discrete-ordinates transport equation in two-dimensional Cartesian (X-Y) geometry for arbitrary polygonal meshes. The discretization is a discontinuous finite element method (DFEM) that utilizes piecewise bi-linear (PWBL) basis functions, which are formally introduced in this paper. We also present a series of numerical results on quadrilateral and polygonal grids and compare these results to a variety of other spatial discretizations that have been shown to be successful on these grid types. Finally, we note that the properties of the PWBL basis functions are such that the leading-order piecewise bi-linear discontinuous finite element (PWBLD) solution will satisfy a reasonably accurate diffusion discretization in the thick diffusion limit, making the PWBLD method a viable candidate for many different classes of transport problems.
Date: December 22, 2010
Creator: Bailey, T S; Chang, J H; Warsa, J S & Adams, M L
System: The UNT Digital Library
Chlorido(4,4',4''-tri-tert-butyl-2,2':6',2''-terpyridine)platinum(II) chloride toluene monosolvate (open access)

Chlorido(4,4',4''-tri-tert-butyl-2,2':6',2''-terpyridine)platinum(II) chloride toluene monosolvate

In the title compound, [PtCl(C₂₇H₃₅N₃)]Cl·C₇H₈, the Ptᴵᴵ atom is coordinated in a pseudo-square-planar fashion by the N atoms of a 4,4',4''-tri-tert-butyl-2,2':6',2''-terpyridine ligand and a Cl atom.
Date: November 22, 2010
Creator: Batrice, Rami J.; Nesterov, Vladimir N. & Smucker, Bradley W.
System: The UNT Digital Library
Chlorido(4,4',4''-tri-tert-butyl-2,2':6',2''-terpyridine)platinum(II) tetrafluorido-borate (open access)

Chlorido(4,4',4''-tri-tert-butyl-2,2':6',2''-terpyridine)platinum(II) tetrafluorido-borate

In the title compound, [PtCl(C₂₇H₃₅N₃)]Cl·C₇H₈, the Ptᴵᴵ atom is coordinated in a pseudo-square-planar coordination, which is typical of Pt-terpyridine complexes.
Date: November 22, 2010
Creator: Batrice, Rami J.; Nesterov, Vladimir N. & Smucker, Bradley W.
System: The UNT Digital Library
Applicability of Transactional Memory to Modern Codes (open access)

Applicability of Transactional Memory to Modern Codes

None
Date: July 22, 2010
Creator: Bihari, B L
System: The UNT Digital Library
A suspended-particle rosette multi-sampler for discrete biogeochemical sampling in low-particle-density waters (open access)

A suspended-particle rosette multi-sampler for discrete biogeochemical sampling in low-particle-density waters

To enable detailed investigations of early stage hydrothermal plume formation and abiotic and biotic plume processes we developed a new oceanographic tool. The Suspended Particulate Rosette sampling system has been designed to collect geochemical and microbial samples from the rising portion of deep-sea hydrothermal plumes. It can be deployed on a remotely operated vehicle for sampling rising plumes, on a wire-deployed water rosette for spatially discrete sampling of non-buoyant hydrothermal plumes, or on a fixed mooring in a hydrothermal vent field for time series sampling. It has performed successfully during both its first mooring deployment at the East Pacific Rise and its first remotely-operated vehicle deployments along the Mid-Atlantic Ridge. It is currently capable of rapidly filtering 24 discrete large-water-volume samples (30-100 L per sample) for suspended particles during a single deployment (e.g. >90 L per sample at 4-7 L per minute through 1 {mu}m pore diameter polycarbonate filters). The Suspended Particulate Rosette sampler has been designed with a long-term goal of seafloor observatory deployments, where it can be used to collect samples in response to tectonic or other events. It is compatible with in situ optical sensors, such as laser Raman or visible reflectance spectroscopy systems, enabling in situ …
Date: June 22, 2010
Creator: Breier, J. A.; Rauch, C. G.; McCartney, K.; Toner, B. M.; Fakra, S. C.; White, S. N. et al.
System: The UNT Digital Library
Iron oxyhydroxide mineralization on microbial extracellular polysaccharides (open access)

Iron oxyhydroxide mineralization on microbial extracellular polysaccharides

Iron biominerals can form in neutral pH microaerophilic environments where microbes both catalyze iron oxidation and create polymers that localize mineral precipitation. In order to classify the microbial polymers that influence FeOOH mineralogy, we studied the organic and mineral components of biominerals using scanning transmission X-ray microscopy (STXM), micro X-ray fluorescence ({mu}XRF) microscopy, and high-resolution transmission electron microscopy (HRTEM). We focused on iron microbial mat samples from a creek and abandoned mine; these samples are dominated by iron oxyhydroxide-coated structures with sheath, stalk, and filament morphologies. In addition, we characterized the mineralized products of an iron-oxidizing, stalk-forming bacterial culture isolated from the mine. In both natural and cultured samples, microbial polymers were found to be acidic polysaccharides with carboxyl functional groups, strongly spatially correlated with iron oxyhydroxide distribution patterns. Organic fibrils collect FeOOH and control its recrystallization, in some cases resulting in oriented crystals with high aspect ratios. The impact of polymers is particularly pronounced as the materials age. Synthesis experiments designed to mimic the biomineralization processes show that the polysaccharide carboxyl groups bind dissolved iron strongly but release it as mineralization proceeds. Our results suggest that carboxyl groups of acidic polysaccharides are produced by different microorganisms to create a …
Date: June 22, 2010
Creator: Chan, Clara S.; Fakra, Sirine C.; Edwards, David C.; Emerson, David & Banfield, Jillian F.
System: The UNT Digital Library
CgWind: A high-order accurate simulation tool for wind turbines and wind farms (open access)

CgWind: A high-order accurate simulation tool for wind turbines and wind farms

CgWind is a high-fidelity large eddy simulation (LES) tool designed to meet the modeling needs of wind turbine and wind park engineers. This tool combines several advanced computational technologies in order to model accurately the complex and dynamic nature of wind energy applications. The composite grid approach provides high-quality structured grids for the efficient implementation of high-order accurate discretizations of the incompressible Navier-Stokes equations. Composite grids also provide a natural mechanism for modeling bodies in relative motion and complex geometry. Advanced algorithms such as matrix-free multigrid, compact discretizations and approximate factorization will allow CgWind to perform highly resolved calculations efficiently on a wide class of computing resources. Also in development are nonlinear LES subgrid-scale models required to simulate the many interacting scales present in large wind turbine applications. This paper outlines our approach, the current status of CgWind and future development plans.
Date: February 22, 2010
Creator: Chand, K K; Henshaw, W D; Lundquist, K A & Singer, M A
System: The UNT Digital Library
Use of Micro X-Ray Absorption Spectroscopy and Diffraction to Delineate Cr(VI) Speciation in COPR (open access)

Use of Micro X-Ray Absorption Spectroscopy and Diffraction to Delineate Cr(VI) Speciation in COPR

The speciation of Cr(VI) in Cromite Ore Processing Residue was investigated by means of bulk XRD, and a combination of micro-XRF, -XAS and -XRD at the Advanced Light Source (ALS), Berkeley, CA, U.S.A.. Bulk XRD yielded one group of phases that contained explicitly Cr(VI) in their structure, Calcium Aluminum Chromium Oxide Hydrates, accounting for 60% of the total Cr(VI). Micro-analyses at ALS yielded complimentary information, confirming that hydrogarnets and hydrotalcites, two mineral groups that can host Cr(VI) in their structure by substitution, were indeed Cr(VI) sinks. Chromatite (CaCrO4) was also identified by micro-XRD, which was not possible with bulk methods due to its low content. The acquisition of micro-XRF elemental maps enabled not only the identification of Cr(VI)-binding phases, but also the understanding of their location within the matrix. This information is invaluable when designing Cr(VI) treatment, to optimize release and availability for reduction.
Date: June 22, 2010
Creator: Chrysochoou, M.; Moon, D. H.; Fakra, S.; Marcus, M.; Dermatas, D. & Christodoulatos, C.
System: The UNT Digital Library
Text and Structural Data Mining of Influenza Mentions in Web and Social Media (open access)

Text and Structural Data Mining of Influenza Mentions in Web and Social Media

This article discusses text and structural data mining of influenza mentions in web and social media.
Date: February 22, 2010
Creator: Corley, Courtney; Cook, Diane J., 1963-; Mikler, Armin R. & Singh, Karan P.
System: The UNT Digital Library
The Jina Reaclib Database: Its Recent Updates and Impact on Type-I X-Ray Bursts (open access)

The Jina Reaclib Database: Its Recent Updates and Impact on Type-I X-Ray Bursts

None
Date: August 22, 2010
Creator: Cyburt, R. H.; Amthor, A. M.; Ferguson, R.; Meisel, Z.; Smith, K.; Warren, S. et al.
System: The UNT Digital Library
Progress on the NSTX Center Stack Upgrade (open access)

Progress on the NSTX Center Stack Upgrade

The National Spherical Torus Experiment (NSTX) will be upgraded to provide increased toroidal field, plasma current and pulse length. This involves the replacement of the so-called center stack, including the inner legs of the Toroidal Field (TF) coil, the Ohmic Heating (OH) coil, and the inner Poloidal Field (PF) coils. In addition the increased performance of the upgrade requires qualification of remaining existing components for higher loads. Initial conceptual design efforts were based on worst-case combinations of possible currents that the power supplies could deliver. This proved to be an onerous requirement and caused many of the outer coils support structures to require costly heavy reinforcement. This has led to the planned implementation of a Digital Coil Protection System (DCPS) to reduce design-basis loads to levels that are more realistic and manageable. As a minimum, all components must be qualified for the increase in normal operating loads with headroom. Design features and analysis efforts needed to meet the upgrade loading are discussed. Mission and features of the DCPS are presented.
Date: September 22, 2010
Creator: Dudek, L.; Chrzanowski, J.; Heitzenroeder, P.; Mangra, D.; Neumeyer, C.; Smith, M. et al.
System: The UNT Digital Library
A Proposal for User-defined Reductions in OpenMP (open access)

A Proposal for User-defined Reductions in OpenMP

Reductions are commonly used in parallel programs to produce a global result from partial results computed in parallel. Currently, OpenMP only supports reductions for primitive data types and a limited set of base language operators. This is a significant limitation for those applications that employ user-defined data types (e. g., objects). Implementing manual reduction algorithms makes software development more complex and error-prone. Additionally, an OpenMP runtime system cannot optimize a manual reduction algorithm in ways typically applied to reductions on primitive types. In this paper, we propose new mechanisms to allow the use of most pre-existing binary functions on user-defined data types as User-Defined Reduction (UDR) operators. Our measurements show that our UDR prototype implementation provides consistently good performance across a range of thread counts without increasing general runtime overheads.
Date: March 22, 2010
Creator: Duran, A; Ferrer, R; Klemm, M; de Supinski, B R & Ayguade, E
System: The UNT Digital Library
New Superheavy Element Isotopes: 242Pu(48Ca,5n)285114 (open access)

New Superheavy Element Isotopes: 242Pu(48Ca,5n)285114

The new, neutron-deficient, superheavy element isotope {sup 285}114 was produced in {sup 48}Ca irradiations of {sup 242}Pu targets at a center-of-target beam energy of 256 MeV (E* = 50 MeV). The {alpha} decay of {sup 285}114 was followed by the sequential {alpha} decay of four daughter nuclides, {sup 281}Cn, {sup 277}Ds, {sup 273}Hs, and {sup 269}Sg. {sup 265}Rf was observed to decay by spontaneous fission. The measured {alpha}-decay Q values were compared with those from a macroscopic-microscopic nuclear mass model to give insight into superheavy element shell effects. The {sup 242}Pu({sup 48}Ca,5n){sup 285}114 cross section was 0.6{sub -0.5}{sup +0.9} pb.
Date: October 22, 2010
Creator: Ellison, Paul A; Gregorich, Kenneth E.; Berryman, Jill S.; Bleuel, Darren L.; Clark, Roderick M.; Dragojevic, Irena et al.
System: The UNT Digital Library
SPECTRAL AMPLITUDE AND PHASE EVOLUTION IN PETAWATT LASER PULSES (open access)

SPECTRAL AMPLITUDE AND PHASE EVOLUTION IN PETAWATT LASER PULSES

The influence of the active gain medium on the spectral amplitude and phase of amplified pulses in a CPA system is studied. Results from a 10-PW example based on Nd-doped mixed glasses are presented. In conclusion, this study shows that, by using spectral shaping and gain saturation in a mixed-glass amplifier, it is possible to produce 124 fs, 1.4 kJ laser pulses. One detrimental effect, the pulse distortion due to resonant amplification medium, has been investigated and its magnitude as well as its compensation calculated.
Date: November 22, 2010
Creator: Filip, C V
System: The UNT Digital Library
Building Energy Information Systems: User Case Studies (open access)

Building Energy Information Systems: User Case Studies

Measured energy performance data are essential to national efforts to improve building efficiency, as evidenced in recent benchmarking mandates, and in a growing body of work that indicates the value of permanent monitoring and energy information feedback. This paper presents case studies of energy information systems (EIS) at four enterprises and university campuses, focusing on the attained energy savings, and successes and challenges in technology use and integration. EIS are broadly defined as performance monitoring software, data acquisition hardware, and communication systems to store, analyze and display building energy information. Case investigations showed that the most common energy savings and instances of waste concerned scheduling errors, measurement and verification, and inefficient operations. Data quality is critical to effective EIS use, and is most challenging at the subsystem or component level, and with non-electric energy sources. Sophisticated prediction algorithms may not be well understood but can be applied quite effectively, and sites with custom benchmark models or metrics are more likely to perform analyses external to the EIS. Finally, resources and staffing were identified as a universal challenge, indicating a need to identify additional models of EIS use that extend beyond exclusive in-house use, to analysis services.
Date: March 22, 2010
Creator: Granderson, Jessica; Piette, Mary Ann & Ghatikar, Girish
System: The UNT Digital Library
Persistence of gamma-H2AX and 53BP1 foci in proliferating and nonproliferating human mammary epithelial cells after exposure to gamma-rays or iron ions (open access)

Persistence of gamma-H2AX and 53BP1 foci in proliferating and nonproliferating human mammary epithelial cells after exposure to gamma-rays or iron ions

To investigate {gamma}-H2AX (phosphorylated histone H2AX) and 53BP1 (tumour protein 53 binding protein No. 1) foci formation and removal in proliferating and non-proliferating human mammary epithelial cells (HMEC) after exposure to sparsely and densely ionizing radiation under different cell culture conditions. HMEC cells were grown either as monolayers (2D) or in extracellular matrix to allow the formation of acinar structures in vitro (3D). Foci numbers were quantified by image analysis at various time points after exposure. Our results reveal that in non-proliferating cells under 2D and 3D cell culture conditions, iron-ion induced {gamma}-H2AX foci were still present at 72 h after exposure, although 53BP1 foci returned to control levels at 48 h. In contrast in proliferating HMEC, both {gamma}-H2AX and 53BP1 foci decreased to control levels during the 24-48 h time interval after irradiation under 2D conditions. Foci numbers decreased faster after {gamma}-ray irradiation and returned to control levels by 12 h regardless of marker, cell proliferation status, and cell culture condition. Conclusions: The disappearance of radiation induced {gamma}-H2AX and 53BP1 foci in HMEC have different dynamics that depend on radiation quality and proliferation status. Notably, the general patterns do not depend on the cell culture condition (2D versus 3D). …
Date: December 22, 2010
Creator: Groesser, Torsten; Chang, Hang; Fontenay, Gerald; Chen, James; Costes, Sylvain V.; Barcellos-Hoff, Mary Helen et al.
System: The UNT Digital Library
Design of District Emergency Operations Centres, and the Case Study of Indian Oil Corporation Jaipur Depot Explosion (open access)

Design of District Emergency Operations Centres, and the Case Study of Indian Oil Corporation Jaipur Depot Explosion

Article on the design of district emergency operations centres and a case study of Indian Oil Corporation Jaipur depot explosion.
Date: November 22, 2010
Creator: Gupta, Kailash
System: The UNT Digital Library
Near-ultraviolet luminescence of N2 irradiated by short x-ray pulses (open access)

Near-ultraviolet luminescence of N2 irradiated by short x-ray pulses

None
Date: April 22, 2010
Creator: Hau-Riege, S.; Bionta, R.; Ryutov, D.; London, R.; Ables, E.; Kishiyama, K. et al.
System: The UNT Digital Library
Epithermal Neutron Source for Neutron Resonance Spectroscopy (NRS) using High Intensity, Short Pulse Lasers (open access)

Epithermal Neutron Source for Neutron Resonance Spectroscopy (NRS) using High Intensity, Short Pulse Lasers

A neutron source for neutron resonance spectroscopy (NRS) has been developed using high intensity, short pulse lasers. This measurement technique will allow for robust measurements of interior ion temperature of laser-shocked materials and provide insight into equation of state (EOS) measurements. The neutron generation technique uses protons accelerated by lasers off of Cu foils to create neutrons in LiF, through (p,n) reactions with {sup 7}Li and {sup 19}F. The distribution of the incident proton beam has been diagnosed using radiochromic film (RCF). This distribution is used as the input for a (p,n) neturon prediction code which is compared to experimentally measured neutron yields. From this calculation, a total fluence of 1.8 x 10{sup 9} neutrons is infered, which is shown to be a reasonable amount for NRS temperature measurement.
Date: April 22, 2010
Creator: Higginson, D. P.; McNaney, J. M.; Swift, D. C.; Bartal, T.; Hey, D. S.; Pape, S. L. et al.
System: The UNT Digital Library
Radiochemistry diagnostics for the National Ignition Facility (open access)

Radiochemistry diagnostics for the National Ignition Facility

Radiochemistry-based techniques will be an important complement to x-ray implosion diagnostics. Simulations demonstrate the value of alpha-induced or deuteron-induced reactions as a direct measurement of static mix contamination in DT-filled ignition capsules. In this proceedings we examine to what extent neutron-induced reactions might be highly correlated with the energetically down-scattered neutron fraction which is, in turn, related to the critical quantity of fuel areal density, {rho}R. Although alpha and deuteron reactions are highly suppressed in HT/D-filled capsules, neutron-induced reactions produce robust abundances and 2% measurements of the relevant radiological ratios is achievable. We conclude that radiochemical data are strongly correlated with the down-scattered fraction and fuel areal density. Unknown physics, primarily uncertainties in the direct T-T fusion neutron cross section and, to a lesser extent, various radiochemical production cross sections are important but calibration shots can be used to reduce these errors. The primary advantage of radiochemistry remains - it is the only technique that samples down-scattered neutrons from the entire capsule during the burn. In particular radiochemistry correlated with other diagnostics can be used to minimize experimental uncertainties and thus maximize gain.
Date: February 22, 2010
Creator: Hoffman, R. D.; Cerjan, C. J.; Shaughnessy, D. A.; Moody, K. J.; Nelson, S. L.; Bernstein, L. A. et al.
System: The UNT Digital Library
Observation of high soft x-ray drive in large-scale hohlraums at the National Ignition Facility (open access)

Observation of high soft x-ray drive in large-scale hohlraums at the National Ignition Facility

None
Date: April 22, 2010
Creator: Kline, J. L.; Glenzer, S. H.; Olson, R. E.; Suter, L. J.; Widmann, K.; Callahan, D. A. et al.
System: The UNT Digital Library
Aluminum-Catalyzed Intramolecular Hydroamination of Aminoalkenes (open access)

Aluminum-Catalyzed Intramolecular Hydroamination of Aminoalkenes

A new aluminium complex bearing a dianionic phenylene-diamine based ligand has been synthesized and shown to catalyze the intramolecular hydroamination of various aminoalkenes.
Date: April 22, 2010
Creator: Koller, Juergen & Bergman, Robert
System: The UNT Digital Library
Thin Silicon MEMS Contact-Stress Sensor (open access)

Thin Silicon MEMS Contact-Stress Sensor

This thin, MEMS contact-stress (CS) sensor continuously and accurately measures time-varying, solid interface loads in embedded systems over tens of thousands of load cycles. Unlike all other interface load sensors, the CS sensor is extremely thin (< 150 {micro}m), provides accurate, high-speed measurements, and exhibits good stability over time with no loss of calibration with load cycling. The silicon CS sensor, 5 mm{sup 2} and 65 {micro}m thick, has piezoresistive traces doped within a load-sensitive diaphragm. The novel package utilizes several layers of flexible polyimide to mechanically and electrically isolate the sensor from the environment, transmit normal applied loads to the diaphragm, and maintain uniform thickness. The CS sensors have a highly linear output in the load range tested (0-2.4 MPa) with an average accuracy of {+-} 1.5%.
Date: March 22, 2010
Creator: Kotovsky, J; Tooker, A & Horsley, D
System: The UNT Digital Library
FLUX MEASUREMENTS FROM A TALL TOWER IN A COMPLEX LANDSCAPE (open access)

FLUX MEASUREMENTS FROM A TALL TOWER IN A COMPLEX LANDSCAPE

The accuracy and representativeness of flux measurements from a tall tower in a complex landscape was assessed by examining the vertical and sector variability of the ratio of wind speed to momentum flux and the ratio of vertical advective to eddy flux of heat. The 30-60 m ratios were consistent with theoretical predictions which indicate well mixed flux footprints. Some variation with sector was observed that were consistent with upstream roughness. Vertical advection was negligible compared with vertical flux except for a few sectors at night. This implies minor influence from internal boundary layers. Flux accuracy is a function of sector and stability but 30-60 m fluxes were found to be generally representative of the surrounding landscape. This paper will study flux data from a 300 m tower, with 4 levels of instruments, in a complex landscape. The surrounding landscape will be characterized in terms of the variation in the ratio of mean wind speed to momentum flux as a function of height and wind direction. The importance of local advection will be assessed by comparing vertical advection with eddy fluxes for momentum and heat.
Date: July 22, 2010
Creator: Kurzeja, R.; Weber, A.; Chiswell, S. & Parker, M.
System: The UNT Digital Library