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Comments Concerning "Study of Molecular Interaction in Binary Liquid Mixtures of Ethyl Acetoacetate with Chloroform and Dimethylsulphoxide using Excess Acoustic Parameters and Spectroscopic Methods (open access)

Comments Concerning "Study of Molecular Interaction in Binary Liquid Mixtures of Ethyl Acetoacetate with Chloroform and Dimethylsulphoxide using Excess Acoustic Parameters and Spectroscopic Methods

Article commenting on a previously published article, "Study of molecular interaction in binary liquid mixtures of ethyl acetoacetate with chloroform and dimethylsulphoxide using excess acoustic parameters and spectroscopic methods."
Date: February 18, 2014
Creator: Acree, William E. (William Eugene) & Stephens, Timothy W.
System: The UNT Digital Library
The Use of Genetics for the Management of a Recovering Population: Temporal Assessment of Migratory Peregrine Falcons in North America (open access)

The Use of Genetics for the Management of a Recovering Population: Temporal Assessment of Migratory Peregrine Falcons in North America

Article on the use of genetics for the management of a recovering population and a temporal assessment of migratory peregrine falcons in North America.
Date: November 18, 2010
Creator: Johnson, Jeff A.; Talbot, Sandra Looman; Sage, George K.; Burnham, Kurt K.; Brown, Joseph W.; Maechtle, Tom L. et al.
System: The UNT Digital Library
Reconfigurable Surface Plasmon Polariton Wave Adapter Designed by Transformation Optics (open access)

Reconfigurable Surface Plasmon Polariton Wave Adapter Designed by Transformation Optics

This article proposes a reconfigurable surface plasmon polariton (SPP) wave adapter designed by transformation optics, which can control the propagation of SPP waves on un-even surfaces.
Date: June 18, 2012
Creator: Arigong, Bayaner; Shao, Jin; Ren, Han; Zheng, Geng; Lutkenhaus, Jeffrey; Kim, HyoungSoo et al.
System: The UNT Digital Library
REMOVAL OF LEGACY PLUTONIUM MATERIALS FROM SWEDEN (open access)

REMOVAL OF LEGACY PLUTONIUM MATERIALS FROM SWEDEN

U.S. Department of Energy’s National Nuclear Security Administration (NNSA) Office of Global Threat Reduction (GTRI) recently removed legacy plutonium materials from Sweden in collaboration with AB SVAFO, Sweden. This paper details the activities undertaken through the U.S. receiving site (Savannah River Site (SRS)) to support the characterization, stabilization, packaging and removal of legacy plutonium materials from Sweden in 2012. This effort was undertaken as part of GTRI’s Gap Materials Program and culminated with the successful removal of plutonium from Sweden as announced at the 2012 Nuclear Security Summit. The removal and shipment of plutonium materials to the United States was the first of its kind under NNSA’s Global Threat Reduction Initiative. The Environmental Assessment for the U.S. receipt of gap plutonium material was approved in May 2010. Since then, the multi-year process yielded many first time accomplishments associated with plutonium packaging and transport activities including the application of the of DOE-STD-3013 stabilization requirements to treat plutonium materials outside the U.S., the development of an acceptance criteria for receipt of plutonium from a foreign country, the development and application of a versatile process flow sheet for the packaging of legacy plutonium materials, the identification of a plutonium container configuration, the first …
Date: August 18, 2013
Creator: Dunn, Kerry A.; Bellamy, J. Steve; Chandler, Greg T.; Iyer, Natraj C.; Koenig, Rich E.; Leduc, D. et al.
System: The UNT Digital Library
High Rate Deposition of High Quality ZnO:Al by Filtered Cathodic Arc (open access)

High Rate Deposition of High Quality ZnO:Al by Filtered Cathodic Arc

High quality ZnO:Al (AZO) thin films were prepared on glass substrates by direct current filtered cathodic arc deposition. Substrate temperature was varied from room temperature to 425oC, and samples were grown with and without the assistance of low power oxygen plasma (75W). For each growth condition, at least 3 samples were grown to give a statistical look at the effect of the growth environment on the film properties and to explore the reproducibility of the technique. Growth rate was in the 100-400 nm/min range but was apparently random and could not be easily traced to the growth conditions explored. For optimized growth conditions, 300-600 nm AZO films had resistivities of 3-6 x 10-4 ?Omega cm, carrier concentrations in the range of 2-4 x 1020 cm3, Hall mobility as high as 55 cm2/Vs, and optical transmittance greater than 90percent. These films are also highly oriented with the c-axis perpendicular to the substrate and a surface roughness of 2-4 nm.
Date: November 18, 2010
Creator: Mendelsberg, Rueben J.; Lim, S.H.N.; Milliron, D.J. & Anders, Andre
System: The UNT Digital Library
REACTOR PHYSICS MODELING OF SPENT RESEARCH REACTOR FUEL FOR TECHNICAL NUCLEAR FORENSICS (open access)

REACTOR PHYSICS MODELING OF SPENT RESEARCH REACTOR FUEL FOR TECHNICAL NUCLEAR FORENSICS

Technical nuclear forensics (TNF) refers to the collection, analysis and evaluation of pre- and post-detonation radiological or nuclear materials, devices, and/or debris. TNF is an integral component, complementing traditional forensics and investigative work, to help enable the attribution of discovered radiological or nuclear material. Research is needed to improve the capabilities of TNF. One research area of interest is determining the isotopic signatures of research reactors. Research reactors are a potential source of both radiological and nuclear material. Research reactors are often the least safeguarded type of reactor; they vary greatly in size, fuel type, enrichment, power, and burn-up. Many research reactors are fueled with highly-enriched uranium (HEU), up to {approx}93% {sup 235}U, which could potentially be used as weapons material. All of them have significant amounts of radiological material with which a radioactive dispersal device (RDD) could be built. Therefore, the ability to attribute if material originated from or was produced in a specific research reactor is an important tool in providing for the security of the United States. Currently there are approximately 237 operating research reactors worldwide, another 12 are in temporary shutdown and 224 research reactors are reported as shut down. Little is currently known about the …
Date: July 18, 2011
Creator: Nichols, T.; Beals, D. & Sternat, M.
System: The UNT Digital Library
Search for Acoustic Signals from Ultra-High Energy Neutrinos in 1500 Km^3 of Sea Water (open access)

Search for Acoustic Signals from Ultra-High Energy Neutrinos in 1500 Km^3 of Sea Water

None
Date: June 18, 2013
Creator: Kurahashi, Naoko; /Stanford U., Phys. Dept.; Vandenbroucke, Justin; /KIPAC, Menlo Park /SLAC; Gratta, Giorgio & /Stanford U., Phys. Dept.
System: The UNT Digital Library
A study of extraterrestrial antineutrino sources with the KamLAND detector (open access)

A study of extraterrestrial antineutrino sources with the KamLAND detector

We present the results of a search for extraterrestrial electron antineutrinos ({bar {nu}}{sub e}'s) in the energy range 8.3 MeV < E{sub {bar {nu}}}{sub e} < 30.8 MeV using the KamLAND detector. In an exposure of 4.53 kton-year, we identify 25 candidate events. All of the candidate events can be attributed to background, most importantly neutral current atmospheric neutrino interactions, setting an upper limit on the probability of {sup 8}B solar {nu}{sub e}'s converting into {bar {nu}}{sub e}'s at 5.3 x 10{sup -5} (90% C.L.). The present data also allows us to set more stringent limits on the diffuse supernova neutrino flux and on the annihilation rates for light dark matter particles.
Date: May 18, 2011
Creator: Collaboration, The KamLAND; Gando, A.; Gando, Y.; Ichimura, K.; Ikeda, H.; Inoue, K. et al.
System: The UNT Digital Library
Matlab Based LOCO (open access)

Matlab Based LOCO

The LOCO algorithm has been used by many accelerators around the world. Although the uses for LOCO vary, the most common use has been to find calibration errors and correct the optics functions. The light source community in particular has made extensive use of the LOCO algorithms to tightly control the beta function and coupling. Maintaining high quality beam parameters requires constant attention so a relatively large effort was put into software development for the LOCO application. The LOCO code was originally written in FORTRAN. This code worked fine but it was somewhat awkward to use. For instance, the FORTRAN code itself did not calculate the model response matrix. It required a separate modeling code such as MAD to calculate the model matrix then one manually loads the data into the LOCO code. As the number of people interested in LOCO grew, it required making it easier to use. The decision to port LOCO to Matlab was relatively easy. It's best to use a matrix programming language with good graphics capability; Matlab was also being used for high level machine control; and the accelerator modeling code AT, [5], was already developed for Matlab. Since LOCO requires collecting and processing a …
Date: October 18, 2011
Creator: Portmann, Greg; Safranek, James & Huang, Xiaobiao
System: The UNT Digital Library
NUCLEAR INCIDENT CAPABILITIES, KNOWLEDGE & ENABLER LEVERAGING (open access)

NUCLEAR INCIDENT CAPABILITIES, KNOWLEDGE & ENABLER LEVERAGING

The detonation of a 10 Kiloton Improvised Nuclear Device (IND) is a serious scenario that the United States must be prepared to address. The likelihood of a single nuclear bomb exploding in a single city is greater today than at the height of the Cold War. Layered defenses against domestic nuclear terrorism indicate that our government continues to view the threat as credible. The risk of such an event is further evidenced by terrorists desire to acquire nuclear weapons. The act of nuclear terrorism, particularly an act directed against a large population center in the United States, will overwhelm the capabilities of many local and state governments to respond, and will seriously challenge existing federal response capabilities. A 10 Kiloton IND detonation would cause total infrastructure damage in a 3-mile radius and levels of radiation spanning out 3,000 square miles. In a densely populated urban area, the anticipated casualties would be in excess of several hundred thousand. Although there would be enormous loss of life, housing and infrastructure, an IND detonation is a recoverable event. We can reduce the risk of these high-consequence, nontraditional threats by enhancing our nuclear detection architecture and establishing well planned and rehearsed plans for coordinated …
Date: April 18, 2011
Creator: Kinney, J.; Newman, J.; Goodwyn, A. & Dewes, J.
System: The UNT Digital Library
Plasma blobs and filaments -- fusion scientists discover secrets of turbulent edge transport (open access)

Plasma blobs and filaments -- fusion scientists discover secrets of turbulent edge transport

None
Date: October 18, 2012
Creator: Cohen, B I; Myra, J; Garcia, O E; Smith, D & Parker, S E
System: The UNT Digital Library
Temperature-induced martensite in magnetic shape memory Fe{sub 2}MnGa observed by photoemission electron microscopy (open access)

Temperature-induced martensite in magnetic shape memory Fe{sub 2}MnGa observed by photoemission electron microscopy

The magnetic domain structure in single crystals of a Heusler shape memory compound near the composition Fe{sub 2}MnGa was observed during phase transition by photoelectron emission microscopy at Beamline 11.0.1.1 of the Advanced Light Source. The behavior is comparable with recent observations of an adaptive martensite phase in prototype Ni{sub 2}MnGa, although the pinning in the recent work is an epitaxial interface and in this work the e#11;ective pinning plane is a boundary between martensitic variants that transform in a self-accommodating way from the single crystal austenite phase present at high temperatures. Temperature dependent observations of the twinning structure give information as to the coupling behavior between the magnetism and the structural evolution.
Date: January 18, 2012
Creator: Jenkins, Catherine; Scholl, Andreas; Kainuma, R.; Elmers, Hans-Joachim & Omori, Toshihiro
System: The UNT Digital Library
Interactions of Ionic Liquids with Uranium and its Bioreduction (open access)

Interactions of Ionic Liquids with Uranium and its Bioreduction

We investigated the influence of ionic liquids (ILs) 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM]{sup +}[PF{sub 6}]{sup -}, N-ethylpyridinium trifluoroacetate [EtPy]{sup +}[CF{sub 3}COO]{sup -} and N-ethylpyridinium tetrafluoroborate [Et-Py]{sup +}[BF{sub 4}]{sup -} on uranium reduction by Clostridium sp. under anaerobic conditions. Potentiometric titration, UV-vis spectrophotometry, LC-MS and EXAFS analyses showed monodentate complexation between uranyl and BF{sub 4}{sup -} PF{sub 6}{sup -}; and bidentate complexation with CF{sub 3}COO{sup -}. Ionic liquids affected the growth of Clostridium sp. as evidenced by decrease in optical density, changes in pH, gas production, and the extent of U(VI) reduction and precipitation of U(IV) from solution. Reduction of U(VI) to U(IV) was observed in the presence of [EtPy][BF{sub 4}] and [BMIM][PF{sub 6}] but not with [EtPy][CF{sub 3}COO].
Date: September 18, 2012
Creator: Zhang, C. & Francis, A.
System: The UNT Digital Library
Using fully coupled hydro-geomechanical numerical test bed to study reservoir stimulation with low hydraulic pressure (open access)

Using fully coupled hydro-geomechanical numerical test bed to study reservoir stimulation with low hydraulic pressure

None
Date: January 18, 2012
Creator: Fu, P.; Johnson, S. M. & Carrigan, C. R.
System: The UNT Digital Library
Descriptor-Based Analysis Applied to HCN Synthesis from NH3 and CH4 (open access)

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

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

Mechanism of Thermal Reversal of the (Fulvalene)tetracarbonyldiruthenium Photoisomerization: Toward Molecular Solar-Thermal Energy Storage

In the currently intensifying quest to harness solar energy for the powering of our planet, most efforts are centered around photoinduced generic charge separation, such as in photovoltaics, water splitting, other small molecule activation, and biologically inspired photosynthetic systems. In contrast, direct collection of heat from sunlight has received much less diversified attention, its bulk devoted to the development of concentrating solar thermal power plants, in which mirrors are used to focus the sun beam on an appropriate heat transfer material. An attractive alternative strategy would be to trap solar energy in the form of chemical bonds, ideally through the photoconversion of a suitable molecule to a higher energy isomer, which, in turn, would release the stored energy by thermal reversal. Such a system would encompass the essential elements of a rechargeable heat battery, with its inherent advantages of storage, transportability, and use on demand. The underlying concept has been explored extensively with organic molecules (such as the norbornadiene-quadricyclane cycle), often in the context of developing photoswitches. On the other hand, organometallic complexes have remained relatively obscure in this capacity, despite a number of advantages, including expanded structural tunability and generally favorable electronic absorption regimes. A highly promising organometallic system …
Date: February 18, 2010
Creator: Kanai, Y; Srinivasan, V; Meier, S K; Vollhardt, K P & Grossman, J C
System: The UNT Digital Library
ACCEPTABILITY ENVELOPE FOR METAL HYDRIDE-BASED HYDROGEN STORAGE SYSTEMS (open access)

ACCEPTABILITY ENVELOPE FOR METAL HYDRIDE-BASED HYDROGEN STORAGE SYSTEMS

The design and evaluation of media based hydrogen storage systems requires the use of detailed numerical models and experimental studies, with significant amount of time and monetary investment. Thus a scoping tool, referred to as the Acceptability Envelope, was developed to screen preliminary candidate media and storage vessel designs, identifying the range of chemical, physical and geometrical parameters for the coupled media and storage vessel system that allow it to meet performance targets. The model which underpins the analysis allows simplifying the storage system, thus resulting in one input-one output scheme, by grouping of selected quantities. Two cases have been analyzed and results are presented here. In the first application the DOE technical targets (Year 2010, Year 2015 and Ultimate) are used to determine the range of parameters required for the metal hydride media and storage vessel. In the second case the most promising metal hydrides available are compared, highlighting the potential of storage systems, utilizing them, to achieve 40% of the 2010 DOE technical target. Results show that systems based on Li-Mg media have the best potential to attain these performance targets.
Date: July 18, 2011
Creator: Hardy, B.; Corgnale, C.; Tamburello, D.; Garrison, S. & Anton, D.
System: The UNT Digital Library
Photodetectors for Scintillator Proportionality Measurement (open access)

Photodetectors for Scintillator Proportionality Measurement

We evaluate photodetectors for use in a Compton Coincidence apparatus designed for measuring scintillator proportionality. There are many requirements placed on the photodetector in these systems, including active area, linearity, and the ability to accurately measure low light levels (which implies high quantum efficiency and high signal-to-noise ratio). Through a combination of measurement and Monte Carlo simulation, we evaluate a number of potential photodetectors, especially photomultiplier tubes and hybrid photodetectors. Of these, we find that the most promising devices available are photomultiplier tubes with high ({approx}50%) quantum efficiency, although hybrid photodetectors with high quantum efficiency would be preferable.
Date: October 18, 2010
Creator: Moses, William W.; Choong, Woon-Seng; Hull, Giulia; Payne, Steve; Cherepy, Nerine & Valentine, J. D.
System: The UNT Digital Library
A Baseline Design for PEP-X: An Ultra-Low Emittance Storage Ring (open access)

A Baseline Design for PEP-X: An Ultra-Low Emittance Storage Ring

None
Date: June 18, 2013
Creator: Cai, Yunhai; Bane, Karl; Bertsche, Kirk; Chao, Alex; Hettel, Robert; Huang, Xiaobiao et al.
System: The UNT Digital Library
Isospin Splittings of Doubly Heavy Baryons (open access)

Isospin Splittings of Doubly Heavy Baryons

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

Performance measurements of the DIXI (dilation x-ray imager) photocathode using a laser produced x-ray source

None
Date: July 18, 2012
Creator: Nagel, S R; Ayers, M J; Felker, B; Smith, R F; Bell, P M; Bradley, D K et al.
System: The UNT Digital Library
Calculation of Coherent Wiggler Radiation Using Eigenfunction Expansion Method (open access)

Calculation of Coherent Wiggler Radiation Using Eigenfunction Expansion Method

None
Date: October 18, 2013
Creator: Zhou, D.; Chin, Y. H.; Ohmi, K. & Stupakov, G.
System: The UNT Digital Library
Transistor operation and mobility enhancement in top-gated LaAlO_3 / SrTiO_3 heterostructures (open access)

Transistor operation and mobility enhancement in top-gated LaAlO_3 / SrTiO_3 heterostructures

None
Date: June 18, 2013
Creator: Hosoda, Masayuki; Hikita, Yasuyuki; Hwang, Harold Y. & Bell1, Christopher
System: The UNT Digital Library
The MINERvA Experiment (open access)

The MINERvA Experiment

The MINERvA experiment is a dedicated cross-section experiment whose aim is to measure neutrino cross sections for inclusive and exclusive final states on several nuclei. The detector is fully commissioned and began running in March 2010. As a dedicated cross-section experiment, MINERvA has a particular need to know the incident neutrino flux: both the absolute level and the energy dependence. In these proceedings we describe the MINERvA detector, give an update on the experimental status, and discuss the means to determine the neutrino flux. The MINERvA experiment is now running and has completed 25% of its full Low Energy run. There are various techniques planned for understanding the flux, including taking neutrino data at several different beam configurations. The experiment has gotten a first glimpse of two of the six configurations, and completed four horn current scans. Because of its exclusive final state reconstruction capabilities MINERvA can provide the much needed input for current and future oscillation experiments. The inclusive final state measurements and comparisons of nuclear effects across as many states as possible will provide new insights into neutrino-nucleus scattering.
Date: March 18, 2011
Creator: Harris, Deborah A. & Kopp, Sacha
System: The UNT Digital Library