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2008 Atomic and Molecular Interactions GRC-July 6-11, 2008 (open access)

2008 Atomic and Molecular Interactions GRC-July 6-11, 2008

The Atomic and Molecular Interactions Gordon Conferences is justifiably recognized for its broad scope, touching on areas ranging from fundamental gas phase and gas-condensed matter collision dynamics, to laser-molecule interactions, photophysics, and unimolecular decay processes. The meeting has traditionally involved scientists engaged in fundamental research in gas and condensed phases and those who apply these concepts to systems of practical chemical and physical interest. A key tradition in this meeting is the strong mixing of theory and experiment throughout. The program for 2008 conference continues these traditions. At the 2008 AMI GRC, there will be talks in 5 broadly defined and partially overlapping areas of intermolecular interactions and chemical dynamics: (1) Photoionization and Photoelectron Spectroscopy; (2) Molecules in Strong Fields; (3) Photodissociation Dynamics; (4) Astrochemistry; and (5) Reaction Dynamics. These areas encompass many of the most productive and exciting areas of chemical physics, including both reactive and nonreactive processes, intermolecular and intramolecular energy transfer, and photodissociation and unimolecular processes. Gas phase dynamics, van der Waals and cluster studies, laser-matter interactions and multiple potential energy surface phenomena will all be discussed. Limited funds are available to support attendance for students and post-docs. Advisors should email the conference chair requesting such support, …
Date: June 3, 2009
Creator: Gray, Arthur Suits Nancy Ryan
System: The UNT Digital Library
Abort Gap Cleaning in RHIC (open access)

Abort Gap Cleaning in RHIC

During the RHIC Au-run in 2001 the 200 MHz storage cavity system was used for the first time. The rebucketing procedure caused significant beam debunching in addition to amplifying debunching due to other mechanisms. At the end of a four hour store, debunched beam could account for approximately 30%-40% of the total beam intensity. Some of it will be in the abort gap. In order to minimize the risk of magnet quenching due to uncontrolled beam losses at the time of a beam dump, a combination of a fast transverse kicker and copper collimators were used to clean the abort gap. This report gives an overview of the gap cleaning procedure and the achieved performance.
Date: June 3, 2002
Creator: Drees, A.; Ahrens, L.; Fliller, R., III; Gassner, D.; McIntyre, G. T.; Michnoff, R. et al.
System: The UNT Digital Library
Abraham Model Correlations for Describing Solute Transfer into 2-Butoxyethanol from Both Water and the Gas Phase at 298 K (open access)

Abraham Model Correlations for Describing Solute Transfer into 2-Butoxyethanol from Both Water and the Gas Phase at 298 K

Article on Abraham model correlations for describing solute transfer into 2-butoxyethanol from both water and the gas phase at 298 K.
Date: June 3, 2015
Creator: Sedov, Igor A.; Stolov, Mikhail; Hart, Erin; Grover, Damini; Zettl, Heidi; Koshevarova, Victoria et al.
System: The UNT Digital Library
ACCELERATOR PHYSICS MODEL OF EXPECTED BEAM LOSS ALONG THE SNS ACCELERATOR FACILITY DURING NORMAL OPERATION. (open access)

ACCELERATOR PHYSICS MODEL OF EXPECTED BEAM LOSS ALONG THE SNS ACCELERATOR FACILITY DURING NORMAL OPERATION.

The most demanding requirement in the design of the SNS accelerator chain is to keep the accelerator complex under hands-on maintenance. This requirement implies a hard limit for residual radiation below 100 mrem/hr at one feet from the vacuum pipe and four hours after shutdown for hundred days of normal operation. It has been shown by measurements as well as simulation [l] that this limit corresponds to 1-2 Watts/meter average beam losses. This loss level is achievable all around the machine except in specific areas where remote handling will be necessary. These areas have been identified and correspond to collimation sections and dumps where a larger amount of controlled beam loss is foreseen. Even if the average level of loss is kept under 1 W/m, there are circumstances under which transient losses occur in the machine. The prompt radiation or potential damage in the accelerator components can not be deduced from an average beam loss of 1 W/m. At the same time, controlled loss areas require a dedicated study to clarify the magnitude and distribution of the beam loss. From the front end to the target, we have estimated the most probable locations for transient losses and given an estimate …
Date: June 3, 2002
Creator: Catalan-Lasheras, N.; Cousineau, S.; Galambos, J.; Holtkamp, N.; Raparia, D.; Shafer, R. et al.
System: The UNT Digital Library
Adjoint sensitivity analysis of a thermal hydraulic system undergoing phase change due to boiling transition. [BWR] (open access)

Adjoint sensitivity analysis of a thermal hydraulic system undergoing phase change due to boiling transition. [BWR]

Sensitivity analysis of practical problems can be performed systematically and very efficiently by using adjoint functions. In areas of interest to nuclear reactors, this efficiency has been amply demonstrated on several widely used codes for neutronics and/or thermal hydraulic calculations. Applications of the adjoint method of sensitivity analysis to models involving phase transitions, where non-differentiability occurs, do not seem to have been reported to date. The purpose of this paper is to report results from a successful adjoint sensitivity analysis of a space- and time-dependent system where phase transition occurs due to boiling. The specific model chosen for this analysis is a simplified but representative model of a BWR pump-trip-type accident. This model is of particular importance to BWR safety, since pump failure is one of the most limiting hypothetical accidents in BWR's. This model simulates an exponential flow decay of initially subcooled FREON-114 flowing through a heated channel and undergoing boiling transition.
Date: June 3, 1984
Creator: Cacuci, D. G.; Wacholder, E.; Kaizerman, S. & Tomerian, N.
System: The UNT Digital Library
Advancing the Deployment of Utility-Scale Photovoltaic Plants in the Northeast (open access)

Advancing the Deployment of Utility-Scale Photovoltaic Plants in the Northeast

As one of the premier research laboratories operated by the Department of Energy, Brookhaven National Laboratory (BNL) is pursuing an energy research agenda that focuses on renewable energy systems and will help to secure the nation's energy security. A key element of the BNL research is the advancement of grid-connected utility-scale solar photovoltaic (PV) plants, particularly in the northeastern part of the country where BNL is located. While a great deal of information has been generated regarding solar PV systems located in mostly sunny, hot, arid climates of the southwest US, very little data is available to characterize the performance of these systems in the cool, humid, frequently overcast climates experienced in the northeastern portion of the country. Recognizing that there is both a need and a market for solar PV generation in the northeast, BNL is pursuing research that will advance the deployment of this important renewable energy resource. BNL's research will leverage access to unique time-resolved data sets from the 37MWp solar array recently developed on its campus. In addition, BNL is developing a separate 1MWp solar research array on its campus that will allow field testing of new PV system technologies, including solar modules and balance of …
Date: June 3, 2012
Creator: Lofaro, Robert; Villaran, Michael & Colli, Alessandra
System: The UNT Digital Library
Application of Absorption Spectroscopy to Actinide Process Analysis and Monitoring (open access)

Application of Absorption Spectroscopy to Actinide Process Analysis and Monitoring

The characteristic strong colors of aqueous actinide solutions form the basis of analytical techniques for actinides based on absorption spectroscopy. Colorimetric measurements of samples from processing activities have been used for at least half a century. This seemingly mature technology has been recently revitalized by developments in chemometric data analysis. Where reliable measurements could formerly only be obtained under well-defined conditions, modern methods are robust with respect to variations in acidity, concentration of complexants and spectral interferents, and temperature. This paper describes two examples of the use of process absorption spectroscopy for Pu analysis at the Savannah River Site, in Aiken, SC. In one example, custom optical filters allow accurate colorimetric measurements of Pu in a stream with rapid nitric acid variation. The second example demonstrates simultaneous measurement of Pu and U by chemometric treatment of absorption spectra. The paper concludes with a description of the use of these analyzers to supplement existing technologies in nuclear materials monitoring in processing, reprocessing, and storage facilities.
Date: June 3, 2010
Creator: Lascola, R. & Sharma, V.
System: The UNT Digital Library
Application of UAL to High Intensity Beam Dynamics Studies in the SNS Accumulator Ring (open access)

Application of UAL to High Intensity Beam Dynamics Studies in the SNS Accumulator Ring

The SNS Ring off-line parallel simulation environment based on the Unified Accelerator Libraries (UAL) has been implemented and used for extensive full-scale beam dynamics studies arising in high-intensity rings. The paper describes the structure of this environment and its application to the development and analysis of the SNS accumulator ring beam loss model including a complex combination of several physical effects.
Date: June 3, 2002
Creator: Malitsky, N.; Fedotov, A. V. & Wei, J.
System: The UNT Digital Library
Assessing distribution shifts and ecophysiological characteristics of the only Antarctic winged midge under climate change scenarios (open access)

Assessing distribution shifts and ecophysiological characteristics of the only Antarctic winged midge under climate change scenarios

Article integrating ecophysiological information with the development of new high-resolution climatic layers for Antarctica, to better understand how the distribution of P. steinenii may respond to change over the next century under different IPCC climate change scenarios. The authors conclude that the species has the potential to expand its distribution to include parts of the west and east coasts of the Antarctic Peninsula and even coastal ice-free areas in parts of continental Antarctica. The authors also propose P. steinenii as an effective native sentinel and indicator species of climate change in the Antarctic.
Date: June 3, 2020
Creator: Contador, Tamara; Gañán, Melisa; Bizama, Gustavo; Fuentes-Jaque, Guillermo; Morales, Luis; Rendoll, Javier et al.
System: The UNT Digital Library
Assessment of a Particle Bed Based Beam Stop (open access)

Assessment of a Particle Bed Based Beam Stop

Accelerator target/beam stop concepts able to withstand the thermal shock induced by intense, undiluted beams are being assessed in this study. Such conditions normally push target materials beyond their limits leading to limited useful life. A number of ingenious options have been attempted to help reduce the level of stress generated. Attention is paid to a very promising option that calls for a target consisting of a cooled particle bed. In such configuration the ability of the particle bed structure to diffuse and attenuate the generated thermal shock waves is being explored by performing comprehensive dynamic analyses that incorporate anticipated energy depositions, thermal diffusion, and wave propagation and attenuation. Further, options of coolant liquid filling the porous structure of the particle bed, including concerns of pressure drop and heat transfer, are evaluated for maximizing particle yield.
Date: June 3, 2002
Creator: Simos, N.; Ludewig, H.; Montanez, P. & Todosow, M.
System: The UNT Digital Library
Assessment of Decay and Storage Area for Activated Materials in the National Ignition Facility (open access)

Assessment of Decay and Storage Area for Activated Materials in the National Ignition Facility

None
Date: June 3, 2011
Creator: Khater, H.; Brereton, S.; Dauffy, L.; Hall, J.; Hansen, L.; Kim, S. et al.
System: The UNT Digital Library
Astrophysical evidence on the equation of state (open access)

Astrophysical evidence on the equation of state

The current situation concerning supernova simulations and the theory of neutron star structure are studied with respect to what they tell about the equation of state. A new mechanism that could help power supernovae is suggested.
Date: June 3, 1988
Creator: Glendenning, N.K.
System: The UNT Digital Library
Automated nondestructive evaluation method for characterizing ceramic and metallic hot gas filters. (open access)

Automated nondestructive evaluation method for characterizing ceramic and metallic hot gas filters.

In advanced coal-fired power generation, one technology under development to clean up hot gases before their use as fuel for gas turbines is rigid ceramic candle filters. These porous filters are typically 1.5 m long and 60 mm in diameter and are made of various ceramic materials, including clay-bonded SiC. The high costs of downtime in a large utility demands that nondestructive evaluation/characterization (NDE/C) methods be available. At shutdowns, data from such analysis are needed to decide which filters are still usable and which need to be replaced, and if possible, to estimate the remaining lifetimes. Thus our objective was to develop reliable low-cost NDE technology for these filters. Our approach was to develop NDE/C technology, referred to as acousto-ultrasonics (AU), for application to hot gas filters. Lamb waves generated by the AU method were analyzed to derive a stress wave factor (SWF). This technology was tested by comparing SWF data with the measured strength for a variety of rigid ceramic filters and was shown to work on iron-aluminide filters as well but no strength data have been obtained on the iron-aluminides at this time.
Date: June 3, 2002
Creator: Ellingson, W. A.; Koehl, E. R.; Deemer, C.; Pastilla, P.; Wheeler, B. & Forster, G. A.
System: The UNT Digital Library
The AWM-SIAM Sonia Kovalesvky Lecture - 3 part Lecture Series (open access)

The AWM-SIAM Sonia Kovalesvky Lecture - 3 part Lecture Series

The Association for Women in Mathematics (AWM) in cooperation with the Society for Industrial and Applied Mathematics (SIAM) and with funding from the Department of Energy initiated a new lecture series. The purpose of the lecture series is to increase the visibility of women who have made significant contributions in applied or computational mathematics. The AWM-SIAM Sonia Kovalevsky Lecture is presented at the SIAM Annual Meeting which is a national conference. The lecturer is a woman who has made distinguished contributions in applied or computational mathematics. The lecturer is determined by the Selection Committee which consists of two members of AWM and two members of SIAM, appointed by the presidents of these organizations. The committee may solicit nominations from other members of the scientific and engineering community. The lectureship may be awarded to any woman in the scientific or engineering community.
Date: June 3, 2003
Creator: Lenhart, Suzanne & Lewis, Jennifer
System: The UNT Digital Library
S-Band High Duty Photo-Injection System. (open access)

S-Band High Duty Photo-Injection System.

None
Date: June 3, 2002
Creator: Wang, X. J.; Babzien, M.; Chang, X. Y.; Lynch, D.; Pjerov, S.; Woodle, M. et al.
System: The UNT Digital Library
Beam Dynamics Experiments in Support of Relativistic Klystrons (open access)

Beam Dynamics Experiments in Support of Relativistic Klystrons

Experiments to study beam dynamics for Relativistic Klystrons (RK) are being performed with a 1-MeV, 600-A induction accelerator beam. The RK is a RF Power source based on induction accelerator technology and conventional resonant output structures. Capable of generating 100's of MW/m at frequencies up to K-band, the RK has been proposed as a driver for a future linear collider in one version of a Two-Beam Accelerator. A critical feasibility issue remaining to be demonstrated is suppression of the transverse instability of the drive beam. This kiloampere beam must transit about a hundred resonance output structures and many hundreds of induction accelerator cavities for the RK to achieve competitive efficiency and cost with respect to other proposed power sources. The RK's strong focusing used to contain the beam in the small aperture resonant structures, repetitive geometry, and reacceleration allow the resonant output structures to be spaced at a betatron phase advance of 360{sup o}. This phase advance (or any integral multiple of 180{sup o}) is beneficial in linear accelerators as the instability growth changes from exponential to linear. In our experiment the beam is contained in a solenoidal focusing channel, RF cavities are spaced every 60 cm, and growth in …
Date: June 3, 2001
Creator: Houck, T & Lidia, S
System: The UNT Digital Library
BEAM DYNAMICS SIMULATIONS IN THE RAPID CYCLING MEDICAL SYNCHROTRON. (open access)

BEAM DYNAMICS SIMULATIONS IN THE RAPID CYCLING MEDICAL SYNCHROTRON.

The Rapid Cycling Medical Synchrotron (RCMS) accelerator is under conceptual design at BNL. We report the results of the beam dynamics studies in the current design RCMS ring lattice with simulation program ORBIT++. In this paper, the designed RCMS ring lattice, the important physical parameters and the simulation program employed in this study are overviewed. The major elements and the numerical parameters included in the simulations are listed and discussed. The evolution of longitudinal beam properties, such as bunch length, bunch height and particle distributions, under RF voltage ramping are studied. The simulation results of the 6D beam dynamics during acceleration including phase space and emittance evolution are presented. Finally, the space charge effects such as tune shift and emittance growth in the RCMS ring are investigated and discussed.
Date: June 3, 2002
Creator: Beebe-Wang, J.; D Imperio, N.; Luccio, A. U. & Zhang, S. Y.
System: The UNT Digital Library
Beam Dynamics Studies for a L-Band Photoinjector. (open access)

Beam Dynamics Studies for a L-Band Photoinjector.

None
Date: June 3, 2002
Creator: Chang, X. Y. & Wang, X. J.
System: The UNT Digital Library
The beryllium quandary: will the lower exposure limits spur new developments in sampling and analysis? (open access)

The beryllium quandary: will the lower exposure limits spur new developments in sampling and analysis?

At the time this article was written, new rulemakings were under consideration at OSHA and the U.S. Department of Energy (DOE) that would propose changes to occupational exposure limits for beryllium. Given these developments, it’s a good time to review the tools and methods available to IHs for assessing beryllium air and surface contamination in the workplace—what’s new and different, and what’s tried and true. The article discusses limit values and action levels for beryllium, problematic aspects of beryllium air sampling, sample preparation, sample analysis, and data evaluation.
Date: June 3, 2013
Creator: Brisson, Michael
System: The UNT Digital Library
Blast wave diagnostic for the petawatt laser system (open access)

Blast wave diagnostic for the petawatt laser system

We report on a diagnostic to measure the trajectory of a blast wave propagating through a plastic target 400 {micro}m thick. This blast wave is generated by the irradiation of the front surface of the target with {approximately} 400 J of 1 {micro}m laser radiation in a 20 ps pulse focused to a {approximately} 50 {micro}m diameter spot, which produces an intensity in excess of 1O{sup 18} W/cm{sup 2}. These conditions approximate a point explosion and a blast wave is predicted to be generated with an initial pressure nearing 1 Gbar which decays as it travels approximately radially outward from the interaction region We have utilized streaked optical pyrometry of the blast front to determine its time of arrival at the rear surface of the target Applications of a self-similar Taylor-Sedov blast wave solution allows the amount of energy deposited to be estimated The experiment, LASNEX design simulations and initial results are discussed.
Date: June 3, 1998
Creator: Budil, K. S.
System: The UNT Digital Library
Calibration of a PEM detector with depth of interactionmeasurement (open access)

Calibration of a PEM detector with depth of interactionmeasurement

We present an in situ calibration technique for the LBNL positron emission mammography (PEM) detector module that is capable of measuring depth of interaction (DOI). The detector module consists of 64LSO crystals coupled on one end to a single photomultiplier tube (PMT) and on the opposite end to a 64 pixel array of silicon photodiodes (PD). The PMT provides an accurate timing pulse, the PDs identify the crystal of interaction, the sum provides a total energy signal and the /splGamma/=PD/(PD+PMT) ratio determines the depth of interaction. We calibrate using the /sup 176/Lu natural background radiation of the LSO crystals. We determine the relative gain (K) of the PMT and PD by minimizing the asymmetry of the /spl Gamma/ distribution. We determine the depth dependence from the width of the /spl Gamma/ distribution with optimal K. The performance of calibrated detector modules is evaluated by averaging results from 12 modules. The energy resolution is a function of depth ranging from 24 percent FWHM at the PD end to 51 percent FWHM at the PMT end, and the DOI resolution ranges from 6 mm FWHM at the PD end to 11 mm FWHM at the PMT end.
Date: June 3, 2004
Creator: Wang, G.-C.; Huber, J. S.; Moses, W. W.; Choong, W. -S. & Maltz, J. S.
System: The UNT Digital Library
Calibration of the Lawrence Livermore National Laboratory Passive-Active Neutron Drum Shuffler for Measurement of Highly Enriched Uranium in Oxides within DOE-STD-3013-2000 Containers (open access)

Calibration of the Lawrence Livermore National Laboratory Passive-Active Neutron Drum Shuffler for Measurement of Highly Enriched Uranium in Oxides within DOE-STD-3013-2000 Containers

Lawrence Livermore National Laboratory (LLNL) uses the LLNL passive-active neutron drum (PAN) shuffler (Canberra Model JCC-92) for accountability measurement of highly enriched uranium (HEU) oxide and HEU in mixed uranium-plutonium (U-Pu) oxide. In June 2002, at the 43rd Annual Meeting of the Institute of Nuclear Material Management, LLNL reported on an extensive effort to calibrate this shuffler, based on standards measurements and extensive simulations, for HEU oxides and mixed U-Pu oxides in thin-walled primary and secondary containers. In August 2002, LLNL began to also use DOE-STD-3013-2000 containers for HEU oxide and mixed U-Pu oxide. These DOE-STD-3013-2000 containers are comprised of a stainless steel convenience can enclosed in welded stainless steel primary and secondary containers. Compared to the double thin-walled containers, the DOE-STD-3013-2000 containers have substantially thicker walls, and the density of materials in these containers was found to extend over a greater range (1.35 g/cm{sup 3} to 4.62 g/cm{sup 3}) than foreseen for the double thin-walled containers. Further, the DOE-STD-3013-2000 Standard allows for oxides containing at least 30 wt% Pu plus U whereas the calibration algorithms for thin-walled containers were derived for virtually pure HEU or mixed U-Pu oxides. An initial series of Monte Carlo simulations of the PAN shuffler …
Date: June 3, 2005
Creator: Mount, M E & O'Connell, W J
System: The UNT Digital Library
CO2 capture in primary and tertiary amines - insights from atomistic modeling (open access)

CO2 capture in primary and tertiary amines - insights from atomistic modeling

None
Date: June 3, 2010
Creator: Maiti, A.; Bourcier, W. L. & Aines, R. D.
System: The UNT Digital Library
Collective Effects and Their Control at the Spallation Neutron Source Ring. (open access)

Collective Effects and Their Control at the Spallation Neutron Source Ring.

One of the primary tasks in the design of the Spallation Neutron Source (SNS) ring is to control collective effects including space charge, transverse and longitudinal instabilities, and electron cloud. Transverse painting is used to alleviate space charge force; longitudinal painting along with chromatic sextupoles are used to enhance Landau damping; injection kicker vacuum pipes are carefully shielded, and extraction kicker impedances are measured in detail and optimized; beam halo, beam loss and electron production are minimized; finally, damping systems at various frequencies are planned. This paper summarizes these design implementations.
Date: June 3, 2002
Creator: Wei, J.; Blaskiewicz, M.; Brodowski, J.; Cameron, P.; Davino, D.; Fedotov, A. V. et al.
System: The UNT Digital Library