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Hybrid Simulations With Dynamical Quarks: Spectra, Screening and Thermodynamics (open access)

Hybrid Simulations With Dynamical Quarks: Spectra, Screening and Thermodynamics

We summarize simulations made by the Argonne/University of Illinois group using the Hybrid algorithm to include dynamical staggered fermions. Recent work on the mass spectrum and screening effects due to the inclusion of four light flavors of dynamical quarks is presented. We also present a brief overview of what we have learned about the finite temperature chiral phase transition. 5 refs., 4 figs., 1 tab.
Date: November 18, 1987
Creator: Sinclair, D. K.
System: The UNT Digital Library
Beam bunching in a final storage ring (open access)

Beam bunching in a final storage ring

A calculation is presented for the final bunching of a particle beam in a synchrotron or storage ring. The voltage per turn, the harmonic number, and the bunching time are obtained. (PMA)
Date: November 18, 1977
Creator: Lambertson, G.R.
System: The UNT Digital Library
Near-real-time actinide concentrations via energy dispersive XRFA for process control and material accountability (open access)

Near-real-time actinide concentrations via energy dispersive XRFA for process control and material accountability

A Co-57 based XRFA system has been installed on-line at ICPP to monitor uranium concentrations after first cycle decontamination. A small, medium, or large collimator is used to restrict fission product (fp) background count rates. Using two 50 mCi sources, 1 gU/1 can be measured to +-2% in 10 min with the medium collimator. A computer-based MCA runs the system automatically, controls an insertable U foil (allows calibration anytime) and an automatic W shutter (permits removal of fp background); prints hourly mean U concentrations and a daily log of past 24-h means. Co-57 sources are changed annually in 1 min without disassembly of a lead-steel enclosure that surrounds the de-entrainment tank and XRFA assembly.
Date: November 18, 1983
Creator: Camp, D. C.; Ruhter, W. D.; Johnson, C. E. & Piper, T. C.
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
A microwave power driver for linac colliders: Gigatron (open access)

A microwave power driver for linac colliders: Gigatron

The gigatron is a new rf amplifier tube designed for linac collider applications. Three design features permit extension of the lasertron concept to very high frequencies. First, a gated field-emitter array is employed for the modulated cathode. Second, a ribbon beam geometry mitigates space charge depression and facilitates efficient output coupling. Third, a traveling wave output coupler is used to obtain optimum coupling to the ribbon beam. This paper describes recent developments in the gigatron design, and progress towards experimental tests. 9 refs., 8 figs., 1 tab.
Date: November 18, 1988
Creator: Bizek, H.M.; Elliott, S.M.; McIntyre, P.M.; Nassiri, A.; Popovic, M.B.; Raparia, D. et al.
System: The UNT Digital Library
PHASE SHIFTS IN pi+ -p SCATTERING AT 310 Mev (open access)

PHASE SHIFTS IN pi+ -p SCATTERING AT 310 Mev

In an experimental program recently completed at the 184-inch synchrocyclotron in Berkeley, data were obtained on elastic {pi}{sup +}-p scattering at a laboratory energy of 310 Mev. Quantities measured were the differential cross section, the total cross section, and the polarization of the recoil protons as a function of center-of-mass angle. We have analyzed the data in terms of S, P, and D waves and have obtained only one acceptable solution. The resultant set of phase shifts is of the Fermi type. The D-wave phase shifts are small but definitely needed to obtain an adequate fit to the data. Owing to the relatively high accuracy of the cross-section data and the inclusion of the results of the polarization experiment, the errors on the small phase shifts have been reduced to less than 1{sup 0}. The differential cross-section and polarization data are given in Tables I and II.
Date: November 18, 1959
Creator: Foote, James H.; Chamberlain, Owen; Rogers, Ernest H.; Steiner,Herbert M.; Wiegand, Clyde & Ypsilantis, Tom
System: The UNT Digital Library
PHYSICS WITH AND PHYSICS OF COLLIDING ELECTRON BEAMS (open access)

PHYSICS WITH AND PHYSICS OF COLLIDING ELECTRON BEAMS

When particle physics is a closed subject which has been condensed into a text book, the material will surely be organized by concepts and not according to what fact was learned on what accelerator. But short of that day facilities must be designed, planned, and developed, and experiments must be executed on one of a number of available accelerators; and a very necessary point of view is to ask what physics can be done with one facility, in contrast to another. It is in this spirit that, in this note, we look at electron colliding beam devices. In the first section we discuss the physics that can be done with colliding electron beams. After some general remarks we review the experiments already performed, and then turn to experiments planned for the future. The physics that can be done with any accelerator is a strong function of the physics of the accelerator. Every reader of this Journal knows what determines the energy of an accelerator, but the physics that determines the beam intensity, quality, and pulse length is perhaps not so well known. In fact, we plan to devote a future Comment to the physics that limits the performance of conventional …
Date: November 18, 1969
Creator: Pellegrini, Claudio & Sessler, Andrew M.
System: The UNT Digital Library
[The military's crumbling gay ban: the year in review] (open access)

[The military's crumbling gay ban: the year in review]

A copy of a newspaper article pertaining to the military's anti-gay and lesbian servicemen policies and how the policies have been challenged by the Lambda Legal Defense and Education Fund.
Date: November 18, 1992
Creator: unknown
System: The UNT Digital Library
Reactor group contribution to heavy ion fusion workshop (open access)

Reactor group contribution to heavy ion fusion workshop

This paper discusses the current status of reactor design for heavy ion fusion.
Date: November 18, 1977
Creator: Maniscalco, J.A.
System: The UNT Digital Library
The QCD vacuum at infinite momentum (open access)

The QCD vacuum at infinite momentum

We outline how ''topological confinement'' can be seen by the analysis of Regge limit infra-red divergences. We suggest that it is a necessary bridge between conventional confinement and the parton model at infinite momentum. It is produced by adding a chiral doublet of color sextet quarks to conventional QCD. An immediate signature of the resultant electroweak symmetry breaking would be large cross-sections for W/sup +/W/sup /minus// and Z/sup 0/Z/sup 0/ pairs at the CERN and Fermilab /bar p/p colliders. 24 refs.
Date: November 18, 1988
Creator: White, A.R.
System: The UNT Digital Library
Statistical properties of cellular automata in the context of learning and recognition: Part 2, inverting local structure theory equations to find cellular automata with specified properties (open access)

Statistical properties of cellular automata in the context of learning and recognition: Part 2, inverting local structure theory equations to find cellular automata with specified properties

This is the second of two lectures. In the first lecture the map from a cellular automaton to a sequence of analytical approximations called the local structure theory was described. In this lecture the inverse map from approximation to the class of cellular automata approximated is constructed. The key matter is formatting the local structure theory equations in terms of block probability estimates weighted by coefficients. The inverse mapping relies on this format. Each possible assignment of values to the coefficients defines a class of automata with related statistical properties. It is suggested that these coefficients serve to smoothly parameterize the space of cellular automata. By varying the values of the parameters a cellular automaton network may be designed so that it has a specified invariant measure. If an invariant measure is considered a ''memory'' of the network, then this variation of parameters to specify the invariant measure must be considered ''learning.'' It is important to note that in this view learning is not the storage of patterns in a network, but rather the tailoring of the dynamics of a network. 7 figs.
Date: November 18, 1988
Creator: Gutowitz, H.A.
System: The UNT Digital Library
Switching transients in a superconducting coil (open access)

Switching transients in a superconducting coil

A study is made of the transients caused by the fast dump of large superconducting coils. Theoretical analysis, computer simulation, and actual measurements are used. Theoretical analysis can only be applied to the simplest of models. In the computer simulations two models are used, one in which the coil is divided into ten segments and another in which a single coil is employed. The circuit breaker that interrupts the current to the power supply, causing a fast dump, is represented by a time and current dependent conductance. Actual measurements are limited to measurements made incidental to performance tests on the MFTF Yin-yang coils. It is found that the breaker opening time is the critical factor in determining the size and shape of the transient. Instantaneous opening of the breaker causes a lightly damped transient with large amplitude voltages to ground. Increasing the opening time causes the transient to become a monopulse of decreasing amplitude. The voltages at the external terminals are determined by the parameters of the external circuit. For fast opening times the frequency depends on the dump resistor inductance, the circuit capacitance, and the amplitude on the coil current. For slower openings the dump resistor inductance and the …
Date: November 18, 1983
Creator: Owen, E. W. & Shimer, D. W.
System: The UNT Digital Library
Development of subcontractor indirect cost and other direct cost at the DOE Fernald Site (open access)

Development of subcontractor indirect cost and other direct cost at the DOE Fernald Site

The Fernald Environmental Restoration Management Corporation (FERMCO) took great strides in the development of cost estimates at Fernald. There have been many opportunities to improve on how the policies and procedures pertaining to cost estimates were to be implemented. As FERMCO took over the existing Fernald facility, the Project Controls Division began to format the estimating procedures and tools to do business at Fernald. The Estimating Department looked at the problems that pre-existed at the site. One of the key problems that FERMCO encountered was how to summarized the direct and indirect accounts of each subcontracted estimate. Direct costs were broken down by prime and sub-prime accounts. This presented a level of detail that had not been experienced at the site before; it also created many issues concerning accounts and definitions to be applied to ``all other accounts associated with a project.`` Existing subcontract indirect cost accounts were reviewed from existing historical estimates. It was found that some were very detailed and some were not. The Estimating Department was given the task of standardizing the accounts and percentages for each of the subcontractor indirect costs. Then, as the project progressed, the percentages could be revised with actual estimates, subcontract comparisons, …
Date: November 18, 1994
Creator: Cossman, R. L.
System: The UNT Digital Library
A Tightly Coupled Particle-Fluid Model for DNA-Laden Flows in Complex Microscale Geometries (open access)

A Tightly Coupled Particle-Fluid Model for DNA-Laden Flows in Complex Microscale Geometries

We present a stable and convergent method for the computation of flows of DNA-laden fluids in microchannels with complex geometry. The numerical strategy combines a ball-rod model representation for polymers tightly coupled with a projection method for incompressible viscous flow. We use Cartesian grid embedded boundary methods to discretize the fluid equations in the presence of complex domain boundaries. A sample calculation is presented showing flow through a packed array microchannel in 2D.
Date: November 18, 2004
Creator: Trebotich, D; Miller, G H; Colella, P; Graves, D T; Martin, D F & Schwartz, P O
System: The UNT Digital Library
Muon Acceleration (open access)

Muon Acceleration

One of the major motivations driving recent interest in FFAGs is their use for the cost-effective acceleration of muons. This paper summarizes the progress in this area that was achieved leading up to and at the FFAG workshop at KEK from July 7-12, 2003. Much of the relevant background and references are also given here, to give a context to the progress we have made.
Date: November 18, 2003
Creator: Berg, S. J.
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
Extended model for Richtmyer-Meshkov mix (open access)

Extended model for Richtmyer-Meshkov mix

We examine four Richtmyer-Meshkov (RM) experiments on shock-generated turbulent mix and find them to be in good agreement with our earlier simple model in which the growth rate h of the mixing layer following a shock or reshock is constant and given by 2{alpha}A{Delta}v, independent of initial conditions h{sub 0}. Here A is the Atwood number ({rho}{sub B}-{rho}{sub A})/({rho}{sub B} + {rho}{sub A}), {rho}{sub A,B} are the densities of the two fluids, {Delta}V is the jump in velocity induced by the shock or reshock, and {alpha} is the constant measured in Rayleigh-Taylor (RT) experiments: {alpha}{sup bubble} {approx} 0.05-0.07, {alpha}{sup spike} {approx} (1.8-2.5){alpha}{sup bubble} for A {approx} 0.7-1.0. In the extended model the growth rate beings to day after a time t*, when h = h*, slowing down from h = h{sub 0} + 2{alpha}A{Delta}vt to h {approx} t{sup {theta}} behavior, with {theta}{sup bubble} {approx} 0.25 and {theta}{sup spike} {approx} 0.36 for A {approx} 0.7. They ascribe this change-over to loss of memory of the direction of the shock or reshock, signaling transition from highly directional to isotropic turbulence. In the simplest extension of the model h*/h{sub 0} is independent of {Delta}v and depends only on A. They find that h*/h{sub …
Date: November 18, 2009
Creator: Mikaelian, K O
System: The UNT Digital Library
Scintillation Properties of Eu2+-Activated Barium Fluoroiodide (open access)

Scintillation Properties of Eu2+-Activated Barium Fluoroiodide

The scintillation properties of powders and single-crystals of BaFI doped with Eu2+ are presented. Single crystals were grown by the vertical Bridgman technique. Under optical and X-ray excitation, the samples exhibit a narrow E2+ 5d-4f transition emission centered at 405 nm. The scintillation light output is estimated to be 55,000+-5,000 photons/MeV at 662 keV with 85percent of the light decaying within 600 ns. An energyresolution of 8.5percent full width at half maximum (FWHM) has been achieved using this scintillator for 662 keV excitation (137Cs source) at room temperature.
Date: November 18, 2009
Creator: Gundiah, Gautam; Bourret-Courchesne, Edith; Bizarri, Gregory; Hanrahan, Stephen M.; Chaudhry, Anurag; Canning, Andrew et al.
System: The UNT Digital Library
Evaluation of Large Volume SrI2(Eu) Scintillator Detectors (open access)

Evaluation of Large Volume SrI2(Eu) Scintillator Detectors

There is an ever increasing demand for gamma-ray detectors which can achieve good energy resolution, high detection efficiency, and room-temperature operation. We are working to address each of these requirements through the development of large volume SrI{sub 2}(Eu) scintillator detectors. In this work, we have evaluated a variety of SrI{sub 2} crystals with volumes >10 cm{sup 3}. The goal of this research was to examine the causes of energy resolution degradation for larger detectors and to determine what can be done to mitigate these effects. Testing both packaged and unpackaged detectors, we have consistently achieved better resolution with the packaged detectors. Using a collimated gamma-ray source, it was determined that better energy resolution for the packaged detectors is correlated with better light collection uniformity. A number of packaged detectors were fabricated and tested and the best spectroscopic performance was achieved for a 3% Eu doped crystal with an energy resolution of 2.93% FWHM at 662keV. Simulations of SrI{sub 2}(Eu) crystals were also performed to better understand the light transport physics in scintillators and are reported. This study has important implications for the development of SrI{sub 2}(Eu) detectors for national security purposes.
Date: November 18, 2010
Creator: Sturm, B. W.; Cherepy, N. J.; Drury, O. B.; Thelin, P. A.; Fisher, S. E.; Magyar, A. F. et al.
System: The UNT Digital Library
Feature-Based Statistical Analysis of Combustion Simulation Data (open access)

Feature-Based Statistical Analysis of Combustion Simulation Data

We present a new framework for feature-based statistical analysis of large-scale scientific data and demonstrate its effectiveness by analyzing features from Direct Numerical Simulations (DNS) of turbulent combustion. Turbulent flows are ubiquitous and account for transport and mixing processes in combustion, astrophysics, fusion, and climate modeling among other disciplines. They are also characterized by coherent structure or organized motion, i.e. nonlocal entities whose geometrical features can directly impact molecular mixing and reactive processes. While traditional multi-point statistics provide correlative information, they lack nonlocal structural information, and hence, fail to provide mechanistic causality information between organized fluid motion and mixing and reactive processes. Hence, it is of great interest to capture and track flow features and their statistics together with their correlation with relevant scalar quantities, e.g. temperature or species concentrations. In our approach we encode the set of all possible flow features by pre-computing merge trees augmented with attributes, such as statistical moments of various scalar fields, e.g. temperature, as well as length-scales computed via spectral analysis. The computation is performed in an efficient streaming manner in a pre-processing step and results in a collection of meta-data that is orders of magnitude smaller than the original simulation data. This meta-data …
Date: November 18, 2011
Creator: Bennett, J; Krishnamoorthy, V; Liu, S; Grout, R; Hawkes, E; Chen, J et al.
System: The UNT Digital Library
Phil Wallace and Theoretical Physics at McGill in the 1950's: A Personal Perspective (open access)

Phil Wallace and Theoretical Physics at McGill in the 1950's: A Personal Perspective

In 1946 Philip (Phil) Russell Wallace joined the Mathematics Department of McGill University as an Associate Professor of Applied Mathematics, apparently because A. H. S. Gillson, Dean of Arts and Science, wanted theoretical physicists to be in the Mathematics Department. He came with the dream of creating a theoretical physics group at McGill. By the spring of 1949, Phil was authorized to recruit two junior faculty in Mathematics. He hired Theodore (Ted) F. Morris from U. Toronto, who joined in September 1949, and me, who came in January 1950. The group had begun. Phil Wallace was born in Toronto in 1915 and grew up there. He entered the University of Toronto in 1933, earned a B.A. in mathematics in 1937, a M.A. in 1938, and a Ph.D. in applied mathematics in 1940 under Leopold Infeld. His Ph.D. thesis in general relativity was entitled 'On the relativistic equations of motion in electromagnetic theory.' In 1940 World War II had engulfed Europe and was having its effect on Canada, but the US was still at peace. L. J. Synge, Head of the Applied Mathematics Department at Toronto, told Wallace that people such as he would be needed in war work, but things …
Date: November 18, 2010
Creator: Jackson, John David
System: The UNT Digital Library
[Fax from Lambda Legal Defense to the Dallas Voice] (open access)

[Fax from Lambda Legal Defense to the Dallas Voice]

Fax from Lambda Legal Defense to the Dallas Voice of an article, "The Military's Crumbling Gay Ban: The Year in Review."
Date: November 18, 1992
Creator: unknown
System: The UNT Digital Library
EM-21 HIGHER WASTE LOADING GLASSES FOR ENHANCED DOE HIGH-LEVEL WASTE MELTER THROUGHPUT STUDIES - 10194 (open access)

EM-21 HIGHER WASTE LOADING GLASSES FOR ENHANCED DOE HIGH-LEVEL WASTE MELTER THROUGHPUT STUDIES - 10194

Supplemental validation data has been generated that will be used to determine the applicability of the current Defense Waste Processing Facility (DWPF) liquidus temperature (T{sub L}) model to expanded DWPF glass regions of interest based on higher waste loadings. For those study glasses which had very close compositional overlap with the model development and/or model validation ranges (except TiO{sub 2} and MgO concentrations), there was very little difference in the predicted and measured TL values, even though the TiO{sub 2} contents were above the 2 wt% upper limit. The results indicate that the current T{sub L} model is applicable in these compositional regions. As the compositional overlap between the model validation ranges diverged from the target glass compositions, the T{sub L} data suggest that the model under-predicted the measured values. These discrepancies imply that there are individual oxides or their combinations that were outside of the model development and/or validation range over which the model was previously assessed. These oxides include B{sub 2}O{sub 3}, SiO{sub 2}, MnO, TiO{sub 2} and/or their combinations. More data is required to fill in these anticipated DWPF compositional regions so that the model coefficients could be refit to account for these differences.
Date: November 18, 2009
Creator: Raszewski, F.; Peeler, D. & Edwards, T.
System: The UNT Digital Library
Co2 geological sequestration (open access)

Co2 geological sequestration

Human activities are increasingly altering the Earth's climate. A particular concern is that atmospheric concentrations of carbon dioxide (CO{sub 2}) may be rising fast because of increased industrialization. CO{sub 2} is a so-called ''greenhouse gas'' that traps infrared radiation and may contribute to global warming. Scientists project that greenhouse gases such as CO{sub 2} will make the arctic warmer, which would melt glaciers and raise sea levels. Evidence suggests that climate change may already have begun to affect ecosystems and wildlife around the world. Some animal species are moving from one habitat to another to adapt to warmer temperatures. Future warming is likely to exceed the ability of many species to migrate or adjust. Human production of CO{sub 2} from fossil fuels (such as at coal-fired power plants) is not likely to slow down soon. It is urgent to find somewhere besides the atmosphere to put these increased levels of CO{sub 2}. Sequestration in the ocean and in soils and forests are possibilities, but another option, sequestration in geological formations, may also be an important solution. Such formations could include depleted oil and gas reservoirs, unmineable coal seams, and deep saline aquifers. In many cases, injection of CO2 into a …
Date: November 18, 2004
Creator: Xu, Tianfu
System: The UNT Digital Library