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Memory Effects in Fractional Brownian Motion with Hurst Exponent H<1/3 (open access)

Memory Effects in Fractional Brownian Motion with Hurst Exponent H<1/3

This article discusses a study on the regression to the origin of a walker driven by dynamically generated fractional Brownian motion.
Date: August 27, 2010
Creator: Bologna, Mauro; Vanni, Fabio; Krokhin, Arkadii A. & Grigolini, Paolo
System: The UNT Digital Library
Inverted Social Reward: Associations between Psychopathic Traits and Self-Report and Experimental Measures of Social Reward (open access)

Inverted Social Reward: Associations between Psychopathic Traits and Self-Report and Experimental Measures of Social Reward

This article describes two studies of individuals with high levels of psychopathic traits. Study 1 explores what aspects of social reward are associated with psychopathic traits, and Study 2 administers these measures to a new group of participants along with two experimental tasks investigating monetary and social reward value.
Date: August 27, 2014
Creator: Foulkes, Lucy; McCrory, Eamon J.; Neumann, Craig S. & Viding, Essi
System: The UNT Digital Library
Parametric nondifferentiable multiobjective fractional programming under (b;Ψ; Φ; ρ)-univexity (open access)

Parametric nondifferentiable multiobjective fractional programming under (b;Ψ; Φ; ρ)-univexity

This article is concerned with optimality conditions and duality results for nondifferentiable multi-objective fractional programming problems.
Date: September 27, 2018
Creator: Antczak, Tadeusz & Verma, Ram U.
System: The UNT Digital Library
IBS for non-gaussian distributions (open access)

IBS for non-gaussian distributions

In many situations distribution can significantly deviate from Gaussian which requires accurate treatment of IBS. Our original interest in this problem was motivated by the need to have an accurate description of beam evolution due to IBS while distribution is strongly affected by the external electron cooling force. A variety of models with various degrees of approximation were developed and implemented in BETACOOL in the past to address this topic. A more complete treatment based on the friction coefficient and full 3-D diffusion tensor was introduced in BETACOOL at the end of 2007 under the name 'local IBS model'. Such a model allowed us calculation of IBS for an arbitrary beam distribution. The numerical benchmarking of this local IBS algorithm and its comparison with other models was reported before. In this paper, after briefly describing the model and its limitations, they present its comparison with available experimental data.
Date: September 27, 2010
Creator: Fedotov, A.; Sidorin, A.O. & Smirnov, A.V.
System: The UNT Digital Library
PRESERVATION OF H2 PRODUCTION ACTIVITY IN NANOPOROUS LATEX COATINGS OF RHODOPSEUDOMONAS PALUSTRIS CGA009 DURING DRY STORAGE AT AMBIENT TEMPERATURES (open access)

PRESERVATION OF H2 PRODUCTION ACTIVITY IN NANOPOROUS LATEX COATINGS OF RHODOPSEUDOMONAS PALUSTRIS CGA009 DURING DRY STORAGE AT AMBIENT TEMPERATURES

To assess the applicability of latex cell coatings as an &quot;off-the-shelf&#x27; biocatalyst, the effect of osmoprotectants, temperature, humidity and O{sub 2} on preservation of H{sub 2} production in Rhodopseudomonas palustris coatings was evaluated. Immediately following latex coating coalescence (24 h) and for up to 2 weeks of dry storage, rehydrated coatings containing different osmoprotectants displayed similar rates of H{sub 2} production. Beyond 2 weeks of storage, sorbitol- treated coatings lost all H{sub 2} production activity, whereas considerable H{sub 2} production was still detected in sucrose- and trehalose-stabilized coatings. The relative humidity level at which the coatings were stored had a significant impact on the recovery and subsequent rates of H{sub 2} production. After 4 weeks storage under air at 60% humidity, coatings produced only trace amounts of H{sub 2} (0-0.1% headspace accumulation), whereas those stored at &lt;5% humidity retained 27-53% of their H{sub 2} production activity after 8 weeks of storage. When stored in argon at &lt;5% humidity and room temperature, R. palustris coatings retained full H{sub 2} production activity for 3 months, implicating oxidative damage as a key factor limiting coating storage. Overall, the results demonstrate that biocatalytic latex coatings are an attractive cell immobilization platform for preservation of …
Date: August 27, 2012
Creator: Milliken, C.; Piskorska, M.; Soule, T.; Gosse, J.; Flickinger, M.; Smith, G. et al.
System: The UNT Digital Library
EFFECTIVE POROSITY IMPLIES EFFECTIVE BULK DENSITY IN SORBING SOLUTE TRANSPORT (open access)

EFFECTIVE POROSITY IMPLIES EFFECTIVE BULK DENSITY IN SORBING SOLUTE TRANSPORT

The concept of an effective porosity is widely used in solute transport modeling to account for the presence of a fraction of the medium that effectively does not influence solute migration, apart from taking up space. This non-participating volume or ineffective porosity plays the same role as the gas phase in single-phase liquid unsaturated transport: it increases pore velocity, which is useful towards reproducing observed solute travel times. The prevalent use of the effective porosity concept is reflected by its prominent inclusion in popular texts, e.g., de Marsily (1986), Fetter (1988, 1993) and Zheng and Bennett (2002). The purpose of this commentary is to point out that proper application of the concept for sorbing solutes requires more than simply reducing porosity while leaving other material properties unchanged. More specifically, effective porosity implies the corresponding need for an effective bulk density in a conventional single-porosity model. The reason is that the designated non-participating volume is composed of both solid and fluid phases, both of which must be neglected for consistency. Said another way, if solute does not enter the ineffective porosity then it also cannot contact the adjoining solid. Conceptually neglecting the fluid portion of the non-participating volume leads to a …
Date: February 27, 2012
Creator: Flach, G.
System: The UNT Digital Library
Studies and proposed changes to the RHIC p-Carbon polarimeters for the upcoming RUN-11 (open access)

Studies and proposed changes to the RHIC p-Carbon polarimeters for the upcoming RUN-11

The RHIC polarized proton complex utilizes polarimeters in each of the Blue and Yellow beams that measure the beam polarization through the p-Carbon elastic scattering process in the Coulomb Nuclear Interference kinematic region. This along with a Polarized Hydrogen Jet Target that utilizes the proton-proton elastic scattering process to first measure the analyzing power of the reaction and using the reverse process to measure the beam polarization. The latter is used to calibrate the p-Carbon polarimeters at the desired beam energy. In Run 9 RHIC ran with beams at center-of-mass energies of 200 and 500 GeV respectively. The higher beam intensities as well as the fact that the 250 GeV beam size is much smaller than that at 100 GeV resulted in significantly higher rates seen by the polarimeters and led to observed instability. In this paper, we will discuss the problems encountered and the tests that were carried out using the AGS as a proxy in an attempt to solve the problems and the path forward we took towards the upcoming polarized proton Run11.
Date: September 27, 2010
Creator: Makdisi, Y.; Alekseev, I.; Aschenauer, E.; Atoian, G.; Bazilevsky, A.; Gill, R. et al.
System: The UNT Digital Library
SYNTHESIZING PRECISION FLEXURES THAT DECOUPLE DISPLACEMENT-BASED ACTUATORS (open access)

SYNTHESIZING PRECISION FLEXURES THAT DECOUPLE DISPLACEMENT-BASED ACTUATORS

None
Date: July 27, 2012
Creator: Hopkins, J B & McCalib, D B
System: The UNT Digital Library
Personal Dose Equivalent Conversion Coefficients For Photons To 1 GEV (open access)

Personal Dose Equivalent Conversion Coefficients For Photons To 1 GEV

The personal dose equivalent, H{sub p}(d), is the quantity recommended by the International Commission on Radiation Units and Measurements (ICRU) to be used as an approximation of the protection quantity Effective Dose when performing personal dosemeter calibrations. The personal dose equivalent can be defined for any location and depth within the body. Typically, the location of interest is the trunk where personal dosemeters are usually worn and in this instance a suitable approximation is a 30 cm X 30 cm X 15 cm slab-type phantom. For this condition the personal dose equivalent is denoted as H{sub p,slab}(d) and the depths, d, are taken to be 0.007 cm for non-penetrating and 1 cm for penetrating radiation. In operational radiation protection a third depth, 0.3 cm, is used to approximate the dose to the lens of the eye. A number of conversion coefficients for photons are available for incident energies up to several MeV, however, data to higher energies are limited. In this work conversion coefficients up to 1 GeV have been calculated for H{sub p,slab}(10) and H{sub p,slab}(3) using both the kerma approximation and by tracking secondary charged particles. For H{sub p}(0.07) the conversion coefficients were calculated, but only to 10 …
Date: September 27, 2010
Creator: Veinot, K. G. & Hertel, N. E.
System: The UNT Digital Library
Monte Carlo Simulation of Neutron Noise Effects on Beam Position Determination With Real and Simulated Beam Images at the National Ignition Facility (open access)

Monte Carlo Simulation of Neutron Noise Effects on Beam Position Determination With Real and Simulated Beam Images at the National Ignition Facility

None
Date: August 27, 2013
Creator: Awwal, A.; Leach, R.; Datte, P. & Manuel, A.
System: The UNT Digital Library
Recent Progress in the NSTX/NSTX-U Lithium Program and Prospects for Reactor-Relevant Liquid-Lithium Based Divertor Development (open access)

Recent Progress in the NSTX/NSTX-U Lithium Program and Prospects for Reactor-Relevant Liquid-Lithium Based Divertor Development

Developing a reactor compatible divertor has been identified as a particularly challenging technology problem for magnetic confinement fusion. While tungsten has been identified as the most attractive solid divertor material, the NSTX/NSTX-U lithium (Li) program is investigating the viability of liquid lithium (LL) as a potential reactor compatible divertor plasma facing component (PFC) . In the near term, operation in NSTX-U is projected to provide reactor-like divertor heat loads &lt; 40 MW/m^2 for 5 s. During the most recent NSTX campaign, ~ 0.85 kg of Li was evaporated onto the NSTX PFCs where a ~50% reduction in heat load on the Liquid Lithium Divertor (LLD) was observed, attributable to enhanced divertor bolometric radiation. This reduced divertor heat flux through radiation observed in the NSTX LLD experiment is consistent with the results from other lithium experiments and calculations. These results motivate an LL-based closed radiative divertor concept proposed here for NSTX-U and fusion reactors. With an LL coating, the Li is evaporated from the divertor strike point surface due to the intense heat. The evaporated Li is readily ionized by the plasma due to its low ionization energies, and the ionized Li ions can radiate strongly, resulting in a significant reduction …
Date: October 27, 2012
Creator: M. Ono, et al.
System: The UNT Digital Library
ANALYSIS OF VENTING OF A RESIN SLURRY (open access)

ANALYSIS OF VENTING OF A RESIN SLURRY

A resin slurry venting analysis was conducted to address safety issues associated with overpressurization of ion exchange columns used in the Purex process at the Savannah River Site (SRS). If flow to these columns were inadvertently interrupted, an exothermic runaway reaction could occur between the ion exchange resin and the nitric acid used in the feed stream. The nitric acid-resin reaction generates significant quantities of noncondensable gases, which would pressurize the column. To prevent the column from rupturing during such events, rupture disks are installed on the column vent lines. The venting analysis models accelerating rate calorimeter (ARC) tests and data from tests that were performed in a vented test vessel with a rupture disk. The tests showed that the pressure inside the test vessel continued to increase after the rupture disk opened, though at a slower rate than prior to the rupture. Calculated maximum discharge rates for the resin venting tests exceeded the measured rates of gas generation, so the vent size was sufficient to relieve the pressure in the test vessel if the vent flow rate was constant. The increase in the vessel pressure is modeled as a transient phenomenon associated with expansion of the resin slurry/gas mixture …
Date: March 27, 2012
Creator: Laurinat, J. & Hensel, S.
System: The UNT Digital Library
RADIOACTIVE ELEMENTS IN THE STANDARD ATOMIC WEIGHTS TABLE (open access)

RADIOACTIVE ELEMENTS IN THE STANDARD ATOMIC WEIGHTS TABLE

In the 1949 Report of the Atomic Weights Commission, a series of new elements were added to the Atomic Weights Table. Since these elements had been produced in the laboratory and were not discovered in nature, the atomic weight value of these artificial products would depend upon the production method. Since atomic weight is a property of an element as it occurs in nature, it would be incorrect to assign an atomic weight value to that element. As a result of that discussion, the Commission decided to provide only the mass number of the most stable (or longest-lived) known isotope as the number to be associated with these entries in the Atomic Weights Table. As a function of time, the mass number associated with various elements has changed as longer-lived isotopes of a particular element has been found in nature, or as improved half-life values of an element's isotopes might cause a shift in the longest-lived isotope from one mass to another. In the 1957 Report of the Atomic Weights Commission, it was decided to discontinue the listing of the mass number in the Atomic Weights Table on the grounds that the kind of information supplied by the mass number …
Date: July 27, 2011
Creator: Holden, N. E.; Holden, N. & Holden, N. E.
System: The UNT Digital Library
Ideal MHD Stability of ITER Steady State Scenarios with ITBs (open access)

Ideal MHD Stability of ITER Steady State Scenarios with ITBs

One of ITER goals is to demonstrate feasibility of continuous operations using non-inductive current drive. Two main candidates have been identified for advanced operations: the long duration, high neutron fluency hybrid scenario and the steady state scenario, both operating at a plasma current lower than the reference ELMy scenario [1][2] to minimize the required current drive. The steady state scenario targets plasmas with current 7-10 MA in the flat-top, 50% of which will be provided by the self-generated, pressure-driven bootstrap current. It has been estimated that, in order to obtain a fusion gain Q &gt; 5 at a current of 9 MA, it should be ΒN &gt; 2.5 and H &gt; 1.5 [3]. This implies the presence of an Internal Transport Barrier (ITB). This work discusses how the stability of steady state scenarios with ITBs is affected by the external heating sources and by perturbations of the equilibrium profiles.
Date: July 27, 2011
Creator: Poli, F. M.; Kessel, C. E.; Jardin, S.; Manickam, J.; Chance, M. & Chen, J.
System: The UNT Digital Library
Plutonium complexation by phosphonate-functionalized mesoporous silica (open access)

Plutonium complexation by phosphonate-functionalized mesoporous silica

MCM-41-type mesoporous silica functionalized with the CMPO-based 'Ac-Phos' silane has been reported in the literature (1) to show good capacity as an acftinide sorbent material, with potential applications in environmental sequestration, aqueous waste separation and/or vitrification, and chemical sensing of actinides in solution. The study explores the complexation of Pu(IV and VI) and other selected actinides and lanthanides by SBA-15 type mesoporous silica functionalized with Ac-Phos. The Pu binding kinetics and binding capacity were determined for both the Ac-Phos functionalized and unmodified SBA-15. They analyzed the binding geometry and redox behavior of Pu(VI) by X-ray absorption spectroscopy (XAS). They discuss the synthesis and characterization of the functionalized mesoporous material, batch sorption experiments, and the detailed analyses of the actinide complexes that are formed. Structural measurements are paired with high-level quantum mechanical modeling to elucidate the binding mechanisms.
Date: October 27, 2010
Creator: Parsons-Moss, T; Schwaiger, L K; Hubaud, A; Hu, Y J; Tuysuz, H; Yang, P et al.
System: The UNT Digital Library
Status Report of the DPHEP Study Group: Towards a Global Effort for Sustainable Data Preservation in High Energy Physics (open access)

Status Report of the DPHEP Study Group: Towards a Global Effort for Sustainable Data Preservation in High Energy Physics

None
Date: March 27, 2013
Creator: Akopov, Zaven; Amerio, Silvia; Asner, David; Avetisyan, Eduard; Barring, Olof; Beacham, James et al.
System: The UNT Digital Library
Suppression of probe background signals via B1 field inhomogeneity (open access)

Suppression of probe background signals via B1 field inhomogeneity

A new approach combining a long pulse with the DEPTH sequence (Cory and Ritchey, Journal of Magnetic Resonance, 1988) greatly improves the efficiency for suppressing probe background signals arising from spinning modules. By applying a long initial excitation pulse in the DEPTH sequence, instead of a {pi}/2 pulse, the inhomogeneous B{sub 1} fields outside the coil can dephase the background coherence in the nutation frame. The initial long pulse and the following two consecutive EXORCYCLE {pi} pulses function complementarily and prove most effective in removing background signals from both strong and weak B{sub 1} fields. Experimentally, the length of the long pulse can be optimized around odd multiples of the {pi}/2 pulse, depending on the individual probe design, to preserve signals inside the coil while minimizing those from probe hardware. This method extends the applicability of the DEPTH sequence to probes with small differences in B{sub 1} field strength between the inside and outside of the coil, and can readily combine with well-developed double resonance experiments for quantitative measurement. In general, spin systems with weak internal interactions are required to attain efficient and uniform excitation for powder samples, and the principles to determine the applicability are discussed qualitatively in terms …
Date: January 27, 2011
Creator: Feng, Jian & Reimer, Jeffrey
System: The UNT Digital Library
The RHIC polarized source upgrade (open access)

The RHIC polarized source upgrade

The RHIC polarized H{sup -} ion source is being upgraded to higher intensity (5-10 mA) and polarization for use in the RHIC polarization physics program at enhanced luminosity RHIC operation. The higher beam peak intensity will allow reduction of the transverse beam emittance at injection to AGS to reduce polarization losses in AGS. There is also a planned RHIC luminosity upgrade by using the electron beam lens to compensate the beam-beam interaction at collision points. This upgrade is also essential for future BNL plans for a high-luminosity electron - proton (ion) Collider eRHIC.
Date: September 27, 2010
Creator: Zelenski, A.; Atoian, G.; Davydenko, V.; Ivanov, A.; Kolmogorov, A.; Ritter, J. et al.
System: The UNT Digital Library
DESIGN OF THE ITER IN-VESSEL COILS (open access)

DESIGN OF THE ITER IN-VESSEL COILS

The ITER project is considering the inclusion of two sets of in-vessel coils, one to mitigate the effect of Edge Localized Modes (ELMs) and another to provide vertical stabilization (VS). The in-vessel location (behind the blanket shield modules, mounted to the vacuum vessel inner wall) presents special challenges in terms of nuclear radiation (~3000 MGy) and temperature (100oC vessel during operations, 200oC during bakeout). Mineral insulated conductors are well suited to this environment but are not commercially available in the large cross section required. An R&amp;D program is underway to demonstrate the production of mineral insulated (MgO or Spinel) hollow copper conductor with stainless steel jacketing needed for these coils. A preliminary design based on this conductor technology has been developed and is presented herein.
Date: November 27, 2010
Creator: Neumeyer, C; Bryant, L; Chrzanowski, J; Feder, R; Gomez, M; Heitzenroeder, P et al.
System: The UNT Digital Library
The Effects of the Scattering by Edge Plasma Density Fluctuations on Lower Hyybrid Wave Propagation (open access)

The Effects of the Scattering by Edge Plasma Density Fluctuations on Lower Hyybrid Wave Propagation

Scattering effects induced by edge density fluctuations on lower hybrid (LH) wave propagation are investigated. The scattering model used here is based on the work of Bonoli and Ott [Phys. Fluids 25 (1982) 361]. It utilizes an electromagnetic wave kinetic equation solved by a Monte Carlo technique. This scattering model has been implemented in GENRAY , a ray tracing code which explicitly simulates wave propagation, as well as collisionless and collisional damping processes, over the entire plasma discharge, including the scrape-off layer (SOL) that extends from the separatrix to the vessel wall. A numerical analysis of the LH wave trajectories and the power deposition profile with and without scattering is presented for Alcator CMod discharges. Comparisons between the measured hard x-ray emission on Alcator C-Mod and simulations of the data obtained from the synthetic diagnostic included in the GENRAY/CQL3D package are shown, with and without the combination of scattering and collisional damping. Implications of these results on LH current drive are discussed.
Date: August 27, 2012
Creator: Bertelli, N.; Bonoli, P. T.; Harvey, R. W.; Smirnov, A. P.; Baek, S. G.; Parker, R. R. et al.
System: The UNT Digital Library
Theoretical Summary Lecture for Higgs Hunting 2012 (open access)

Theoretical Summary Lecture for Higgs Hunting 2012

In this lecture, I review some of the perspectives on the Higgs boson discussed at the Higgs Hunting 2012 Worshop and discuss the short- and long-term aspects of Higgs physics.
Date: August 27, 2012
Creator: Peskin, Michael E.
System: The UNT Digital Library
Reconciling sampling and direct instrumentation for unintrusive call-path profiling of MPI programs (open access)

Reconciling sampling and direct instrumentation for unintrusive call-path profiling of MPI programs

None
Date: January 27, 2011
Creator: Szebenyi, Z; Gamblin, T; Schulz, M; de Supinski, B; Wolf, F & Wylie, B
System: The UNT Digital Library
Interactive Visualizations for Performance Analysis of Heterogeneous Computing Clusters (open access)

Interactive Visualizations for Performance Analysis of Heterogeneous Computing Clusters

None
Date: January 27, 2012
Creator: Landge, A; Levine, J; Bremer, P; Schulz, M; Gamblin, T; Bhatele, A et al.
System: The UNT Digital Library
9975 SHIPPING PACKAGE LIFE EXTENSION SURVEILLANCE PROGRAM RESULTS SUMMARY (open access)

9975 SHIPPING PACKAGE LIFE EXTENSION SURVEILLANCE PROGRAM RESULTS SUMMARY

Results from the 9975 shipping package Storage and Surveillance Program at the Savannah River Site (SRS) are summarized for justification to extend the life of the 9975 packages currently stored in the K-Area Complex (KAC). This justification is established with the stipulation that surveillance activities will continue throughout the extended time to ensure the continued integrity of the 9975 materials of construction and to further understand the currently identified degradation mechanisms. The 10 year storage life justification was developed prior to storage. A subsequent report was later used to validate the qualification of the 9975 shipping packages for 10 years in storage. However the qualification for the storage period was provided by the monitoring requirements of the 9975 Storage and Surveillance Program. This report summarizes efforts to determine a new safe storage limit for the 9975 shipping package based on the surveillance data collected since 2005 when the 9975 Storage and Surveillance Program began. The Program has demonstrated that the 9975 package has a robust design that can perform under a variety of conditions. The primary emphasis of the on-going 9975 Storage and Surveillance Program is an aging study of the 9975 Viton{reg_sign} containment vessel O-rings and the Celotex{reg_sign} fiberboard …
Date: May 27, 2011
Creator: Dunn, K.; Daugherty, W.; Hackney, B.; Hoffman, E. & Skidmore, E.
System: The UNT Digital Library