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Resistance to impact criteria can lead to a tightening of the accountability noose (open access)

Resistance to impact criteria can lead to a tightening of the accountability noose

Article discussing research on how the resistance to impact criteria can lead to a tightening of the accountability noose.
Date: March 15, 2012
Creator: Holbrook, J. Britt & Frodeman, Robert
System: The UNT Digital Library
Safe from Harm: Learned, Instructed, and Symbolic Generalization Pathways of Human Threat-Avoidance (open access)

Safe from Harm: Learned, Instructed, and Symbolic Generalization Pathways of Human Threat-Avoidance

Article on learned, instructed, and symbolic generalization pathways of human threat-avoidance.
Date: October 15, 2012
Creator: Dymond, Simon; Schlund, Michael W.; Roche, Bryan; Houwer, Jan de & Freegard, Gary P.
System: The UNT Digital Library
Key cell signaling pathways modulated by zerumbone: Role in the prevention and treatment of cancer (open access)

Key cell signaling pathways modulated by zerumbone: Role in the prevention and treatment of cancer

Article on key cell signaling pathways modulated by zerumbone and the role in the prevention and treatment of cancer.
Date: November 15, 2012
Creator: Prasannan, Remya; Kalesh, Karunakaran A.; Shanmugam, Muthu K.; Nachiyappan, Alamelu; Ramachandran, Lalitha; Nguyen, An H. et al.
System: The UNT Digital Library
Recent T980 Crystal Collimation Studies at the Tevatron Exploiting a Pixel Detector System and a Multi-Strip Crystal Array (open access)

Recent T980 Crystal Collimation Studies at the Tevatron Exploiting a Pixel Detector System and a Multi-Strip Crystal Array

With the shutdown of the Tevatron, the T-980 crystal collimation experiment at Fermilab has been successfully completed. Results of dedicated beam studies in May 2011 are described in this paper. For these studies, two multi-strip crystals were installed in the vertical goniometer and an O-shaped crystal installed in a horizontal goniometer. A two-plane CMS pixel detector was also installed in order to enhance the experiment with the capability to image the profile of crystal channeled or multiple volume reflected beam. The experiment successfully imaged channeled beam from a crystal for 980-GeV protons for the first time. This new enhanced hardware yielded impressive results. The performance and characterization of the crystals studied have been very reproducible over time and consistent with simulations.
Date: May 15, 2012
Creator: Still, D.; Annala, G. E.; Carrigan, R. A.; Drozhdin, A. I.; Johnson, T. R.; Mokhov, N. V. et al.
System: The UNT Digital Library
Coherent electron cooling proof of principle instrumentation design (open access)

Coherent electron cooling proof of principle instrumentation design

The goal of the Coherent Electron Cooling Proof-of-Principle (CeC PoP) experiment being designed at RHIC is to demonstrate longitudinal (energy spread) cooling before the expected CD-2 for eRHIC. The scope of the experiment is to longitudinally cool a single bunch of 40 GeV/u gold ions in RHIC. This paper will describe the instrumentation systems proposed to meet the diagnostics challenges. These include measurements of beam intensity, emittance, energy spread, bunch length, position, orbit stability, and transverse and temporal alignment of electron and ion beams.
Date: April 15, 2012
Creator: M., Gassner D.; Litvinenko, V.; Michnoff, R.; Miller, T.; Minty, M. & Pinayev, I.
System: The UNT Digital Library
Extending MC-SURE to Denoise Sensor Data Streams (open access)

Extending MC-SURE to Denoise Sensor Data Streams

None
Date: November 15, 2012
Creator: Ndoye, M. & Kamath, C.
System: The UNT Digital Library
Evaluating Unsupervised Ensembles when applied to Word Sense Induction (open access)

Evaluating Unsupervised Ensembles when applied to Word Sense Induction

None
Date: February 15, 2012
Creator: Stevens, K D
System: The UNT Digital Library
Threshold for Electron Trapping Nonlinearity in Langmuir Waves (open access)

Threshold for Electron Trapping Nonlinearity in Langmuir Waves

None
Date: August 15, 2012
Creator: Strozzi, D. J.; Williams, E. A.; Rose, H. A.; Hinkel, D. E.; Langdon, A. B. & Banks, J. W.
System: The UNT Digital Library
Elementary Processes Underlying Alpha Channeling in Tokamaks (open access)

Elementary Processes Underlying Alpha Channeling in Tokamaks

Alpha channeling in tokamaks is speculative, but also extraordinarily attractive. Waves that can accomplish this effect have been identified. Key aspects of the theory now enjoy experimental confirmation. This paper will review the elementary processes of wave-particle interactions in plasma that underlie the alpha channeling effect
Date: June 15, 2012
Creator: Fisch, NM.J.
System: The UNT Digital Library
Design of a proton-electron beam overlap monitor for the new RHIC electron lens, based on detecting energetic backscattered electrons (open access)

Design of a proton-electron beam overlap monitor for the new RHIC electron lens, based on detecting energetic backscattered electrons

The optimal performance of the two electron lenses that are being implemented for high intensity polarized proton operation of RHIC requires excellent collinearity of the {approx}0.3 mm RMS wide electron beams with the proton bunch trajectories over the {approx}2m interaction lengths. The main beam overlap diagnostic tool will make use of electrons backscattered in close encounters with the relativistic protons. These electrons will spiral along the electron guiding magnetic field and will be detected in a plastic scintillator located close to the electron gun. A fraction of these electrons will have energies high enough to emerge from the vacuum chamber through a thin window thus simplifying the design and operation of the detector. The intensity of the detected electrons provides a measure of the overlap between the e- and the opposing proton beams. Joint electron arrival time and energy discrimination may be used additionally to gain some longitudinal position information with a single detector per lens.
Date: April 15, 2012
Creator: T., Thieberger; Beebe, E.; Fischer, W.; Gassner, D.; Gu, X.; Hamdi, K. et al.
System: The UNT Digital Library
Summary of Fermilab's Recycler Electron Cooler Operation and Studies (open access)

Summary of Fermilab's Recycler Electron Cooler Operation and Studies

Fermilab's Recycler ring was used as a storage ring for accumulation and subsequent manipulations of 8 GeV antiprotons destined for the Tevatron collider. To satisfy these missions, a unique electron cooling system was designed, developed and successfully implemented. The most important features that distinguish the Recycler cooler from other existing electron coolers are its relativistic energy, 4.3 MV combined with 0.1-0.5 A DC beam current, a weak continuous longitudinal magnetic field in the cooling section, 100 G, and lumped focusing elsewhere. With the termination of the Tevatron collider operation, so did the cooler. In this article, we summarize the experience of running this unique machine.
Date: May 15, 2012
Creator: Prost, L. R. & Shemyakin, A.
System: The UNT Digital Library
Long Term Thermal Stability In Air Of Ionic Liquid Based Alternative Heat Transfer Fluids For Clean Energy Production (open access)

Long Term Thermal Stability In Air Of Ionic Liquid Based Alternative Heat Transfer Fluids For Clean Energy Production

The purpose of this study was to investigate the effect of long-term aging on the thermal stability and chemical structure of seven different ILs so as to explore their suitability for use as a heat transfer fluid. This was accomplished by heating the ILs for 15 weeks at 200�C in an oxidizing environment and performing subsequent analyses on the aged chemicals.
Date: October 15, 2012
Creator: Fox, Elise B; Kendrick, Sarah E.; Visser, Ann E. & Bridges, Nicholas J.
System: The UNT Digital Library
Atomic data for the ITER Core Imaging X-ray Spectrometer (open access)

Atomic data for the ITER Core Imaging X-ray Spectrometer

The parameters of the ITER core plasmas will be measured using the Core Imaging X-ray Spectrometer (CIXS), a high-resolution crystal spectrometer focusing on the L-shell spectra of highly ionized tungsten atoms. In order to correctly infer the plasma properties accurate atomic data are required. Here, some aspects of the underlying physics are discussed using experimental data and theoretical predictions from modeling.
Date: June 15, 2012
Creator: Clementson, J.; Beiersdorfer, P.; Biedermann, C.; Bitter, M.; Delgado-Aparicio, L. F.; Graf, A. et al.
System: The UNT Digital Library
Development of Transparent Ceramic Ce-Doped Gadolinium Garnet Gamma Spectrometers (open access)

Development of Transparent Ceramic Ce-Doped Gadolinium Garnet Gamma Spectrometers

None
Date: November 15, 2012
Creator: Cherepy, N J; Seeley, Z M; Payne, S A; Beck, P R; Drury, O B; O'Neal, S P et al.
System: The UNT Digital Library
Don't Mess with the NEST (open access)

Don't Mess with the NEST

NEST stands for Nuclear Emergency Support Team. The NEST Mission Statement as first established: (1) Conduct, direct, coordinate search and recovery operations for nuclear material, weapons or devices; and (2) Assist in identification and deactivation of Improvised Nuclear Devices (INDs) and Radiological Dispersal Devices (RDDs). Then in 1980 a very sophisticated improvised explosive device was found at Harvey's Casino at Lake Tahoe, Nevada. The FBI and Bomb Squads were unprepared and it detonated. As a result the additional phrase 'and Sophisticated Improvised Explosive Devices (SIEDs)' was added to the Mission Statement.
Date: March 15, 2012
Creator: Larson, M
System: The UNT Digital Library
Bounds and self-consistent estimates for elastic constants of polycrystals of hcp solid He{sup 4} (open access)

Bounds and self-consistent estimates for elastic constants of polycrystals of hcp solid He{sup 4}

Recent advances in methods for computing both Hashin-Shtrikman bounds and related selfconsistent (or CPA) estimates of elastic constants for polycrystals composed of randomly oriented crystals can be applied successfully to hexagonal close packed solid He{sup 4}. In particular, since the shear modulus C{sub 44} of hexagonal close-packed solid He is known to undergo large temperature variations when 20 mK {<=}#20; T {<=}#20; 200 mK, bounds and estimates computed with this class of effective medium methods, while using C{sub 44} {r_arrow} 0 as a proxy for melting, are found to be both qualitatively and quantitatively very similar to prior results obtained using Monte Carlo methods. Hashin- Shtrikman bounds provide significantly tighter constraints on the polycrystal behavior than do the traditional Voigt and Reuss bounds.
Date: February 15, 2012
Creator: Berryman, J. G.
System: The UNT Digital Library
Application of Spatially Resolved High Resolution Crystal Spectrometry to ICF Plasmas (open access)

Application of Spatially Resolved High Resolution Crystal Spectrometry to ICF Plasmas

High resolution (λ/Δ#3;λ ~ 10 000) 1D imaging x-ray spectroscopy using a spherically bent crystal and a 2D hybrid pixel array detector is used world wide for Doppler measurements of ion-temperature and plasma flow-velocity profiles in magnetic confinement fusion plasmas. Meter sized plasmas are diagnosed with cm spatial resolution and 10 ms time resolution. This concept can also be used as a diagnostic of small sources, such as inertial confinement fusion plasmas and targets on x-ray light source beam lines, with spatial resolution of micrometers, as demonstrated by laboratory experiments using a 250-μm 55 Fe source, and by ray-tracing calculations. Throughput calculations agree with measurements, and predict detector counts in the range 10-8 -10-6 times source x-rays, depending on crystal reflectivity and spectrometer geometry. Results of the lab demonstrations, application of the technique to the National Ignition Facility (NIF), and predictions of performance on NIF will be presented.
Date: September 15, 2012
Creator: Hill, Kenneth W.; Bitter, M.; Delgado-Aprico, L.; Pablant, N. A.; Beirersdorfer, P.; Schneider, M. et al.
System: The UNT Digital Library
Conceptual Design of a High Precision Dual Directional Beam Position Monitoring System for Beam Crosstalk Cancellation and Improved Output Pulse Shapes (open access)

Conceptual Design of a High Precision Dual Directional Beam Position Monitoring System for Beam Crosstalk Cancellation and Improved Output Pulse Shapes

The Relativistic Heavy Ions Collider (RHIC) would benefit from improved beam position measurements near the interaction points that see both beams, especially as the tolerances become tighter when reducing the beam sizes to obtain increased luminosity. Two limitations of the present beam position monitors (BPMs) would be mitigated if the proposed approach is successful. The small but unavoidable cross-talk between signals from bunches traveling in opposite directions when using conventional BPMs will be reduced by adopting directional BPMs. Further improvements will be achieved by cancelling residual cross-talk using pairs of such BPMs. Appropriately delayed addition and integration of the signals will also provide pulses with relatively flat maxima that will be easier to digitize by relaxing the presently very stringent timing requirements.
Date: April 15, 2012
Creator: Thieberger, P.; Dawson, C.; Fischer, W.; Gassner, D.; Hulsart, R.; Mernick, K. et al.
System: The UNT Digital Library
Phase Fluctuations and the Absence of Topological Defects in Photo-excited Charge Ordered Nickelate (open access)

Phase Fluctuations and the Absence of Topological Defects in Photo-excited Charge Ordered Nickelate

The dynamics of an order parameter's amplitude and phase determines the collective behaviour of novel states emerging in complex materials. Time- and momentum-resolved pump-probe spectroscopy, by virtue of measuring material properties at atomic and electronic time scales out of equilibrium, can decouple entangled degrees of freedom by visualizing their corresponding dynamics in the time domain. Here we combine time-resolved femotosecond optical and resonant X-ray diffraction measurements on charge ordered La{sub 1.75}Sr{sub 0.25}NiO{sub 4} to reveal unforeseen photoinduced phase fluctuations of the charge order parameter. Such fluctuations preserve long-range order without creating topological defects, distinct from thermal phase fluctuations near the critical temperature in equilibrium. Importantly, relaxation of the phase fluctuations is found to be an order of magnitude slower than that of the order parameter's amplitude fluctuations, and thus limits charge order recovery. This new aspect of phase fluctuations provides a more holistic view of the phase's importance in ordering phenomena of quantum matter.
Date: May 15, 2012
Creator: Lee, W.S.; Chuang, Y.D.; Moore, R.G.; Zhu, Y.; Patthey, L.; Trigo, M. et al.
System: The UNT Digital Library
The effect of high-level waste glass composition on spinel liquidus temperature (open access)

The effect of high-level waste glass composition on spinel liquidus temperature

Spinel crystals precipitate in high-level waste glasses containing Fe, Cr, Ni, Mn, Zn, and Ru. The liquidus temperature (T{sub L}d) of spinel as the primary crystallization phase is a function of glass composition, and the spinel solubility (c{sub o}) is a function of both glass composition and temperature (T). Previously reported models of T{sub L} as a function of composition are based on T{sub L} measured directly, which requires laborious experimental procedures. Viewing the curve of c{sub o} versus T as the liquidus line allows a significant broadening of the composition region for model fitting. This paper estimates T{sub L} as a function of composition based on c{sub o} data obtained with the X-ray diffraction technique.
Date: November 15, 2012
Creator: Kruger, A. A.; Riley, Brian J.; Crum, Jarrod V.; Hrma, Pavel & Matyas, Josef
System: The UNT Digital Library
Evaluation of the United States Support Program’s Internship and Junior Professional Officer Programs (open access)

Evaluation of the United States Support Program’s Internship and Junior Professional Officer Programs

The U.S. Support Program (USSP) to International Atomic Energy Agency (IAEA) Safeguards established a program of one-year paid internships for students and recent graduates. The program was in effect from 2002 until 2006 with a total of forty-one U.S. citizens and permanent residents placed in the IAEA. The USSP created a Junior Professional Officer (JPO) Program in 2005 that replaced the internship program at the IAEA. The JPO program creates opportunities for U.S. college graduates to become IAEA employees for a period of one to two years to help increase the effectiveness and efficiency of safeguards. The twenty three former and current JPOs work in varying fields such as software development, information collection and analysis, non-destructive analysis systems, and unattended monitoring systems. This paper will look at the impacts of the USSP internship and JPO program on the interns and JPOs, the U.S. government, and the IAEA. Academic backgrounds, past involvement in nuclear fields, program assessment, and post-program positions were recorded and analyzed through two studies using questionnaires sent to former interns and former and current JPOs. This paper will discuss the effects of the programs on the careers of the interns and JPOs, present the evaluations of the internship …
Date: July 15, 2012
Creator: J., Cruz; Patterson, J. & Pepper, S.
System: The UNT Digital Library
Femtosecond Single-Shot Imaging of Nanoscale Ferromagnetic Order in Co/Pd Multilayers using Resonant X-ray Holography (open access)

Femtosecond Single-Shot Imaging of Nanoscale Ferromagnetic Order in Co/Pd Multilayers using Resonant X-ray Holography

We present the first single-shot images of ferromagnetic, nanoscale spin order taken with femtosecond x-ray pulses. X-ray-induced electron and spin dynamics can be outrun with pulses shorter than 80 fs in the investigated fluence regime, and no permanent aftereffects in the samples are observed below a fluence of 25 mJ/cm{sup 2}. Employing resonant spatially-muliplexed x-ray holography results in a low imaging threshold of 5 mJ/cm{sup 2}. Our results open new ways to combine ultrafast laser spectroscopy with sequential snapshot imaging on a single sample, generating a movie of excited state dynamics.
Date: May 15, 2012
Creator: Wang, Tianhan; Zhu, Diling; Benny Wu,; Graves, Catherine; Schaffert, Stefan; Rander, Torbjorn et al.
System: The UNT Digital Library
U.S. Citizens Working in International Organizations in Vienna, Austria (open access)

U.S. Citizens Working in International Organizations in Vienna, Austria

N/A
Date: July 15, 2012
Creator: D., Occhiogrosso; S., Pepper; MacArthur, L. & Collins, T.
System: The UNT Digital Library
Statistical line-by-line model for atomic spectra in intermediate coupling (open access)

Statistical line-by-line model for atomic spectra in intermediate coupling

None
Date: February 15, 2012
Creator: Iglesias, C
System: The UNT Digital Library