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Focal Plane Metrology for the LSST Camera

Description: Meeting the science goals for the Large Synoptic Survey Telescope (LSST) translates into a demanding set of imaging performance requirements for the optical system over a wide (3.5{sup o}) field of view. In turn, meeting those imaging requirements necessitates maintaining precise control of the focal plane surface (10 {micro}m P-V) over the entire field of view (640 mm diameter) at the operating temperature (T {approx} -100 C) and over the operational elevation angle range. We briefly describe the hierarchical design approach for the LSST Camera focal plane and the baseline design for assembling the flat focal plane at room temperature. Preliminary results of gravity load and thermal distortion calculations are provided, and early metrological verification of candidate materials under cold thermal conditions are presented. A detailed, generalized method for stitching together sparse metrology data originating from differential, non-contact metrological data acquisition spanning multiple (non-continuous) sensor surfaces making up the focal plane, is described and demonstrated. Finally, we describe some in situ alignment verification alternatives, some of which may be integrated into the camera's focal plane.
Date: January 10, 2007
Creator: A Rasmussen, Andrew P.; Hale, Layton; Kim, Peter; Lee, Eric; Perl, Martin; Schindler, Rafe et al.
Partner: UNT Libraries Government Documents Department
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Edge Turbulence Velocity Changes with Lithium Coating on NSTX

Description: Lithium coating improves energy confinement and eliminates edge localized modes in NSTX, but the mechanism of this improvement is not yet well understood. We used the gas-puff-imaging (GPI) diagnostic on NSTX to measure the changes in edge turbulence which occurred during a scan with variable lithium wall coating, in order to help understand the reason for the confinement improvement with lithium. There was a small increase in the edge turbulence poloidal velocity and a decrease in the poloidal velocity fluctuation level with increased lithium. The possible effect of varying edge neutral density on turbulence damping was evaluated for these cases in NSTX. __________________________________________________
Date: August 10, 2012
Creator: A. Cao, S.J. Zweben, D.P. Stotler, M. Bell, A. Diallo, S.M. Kaye and B. LeBlanc
Partner: UNT Libraries Government Documents Department
open access

Potential for luminosity improvement for low-energy RHIC operation with long bunches

Description: Electron cooling was proposed to increase luminosity of the RHIC collider for heavy ion beams at low energies. Luminosity decreases as the square of bunch intensity due to the beam loss from the RF bucket as a result of the longitudinal intra beam scattering (IBS), as well as due to the transverse emittance growth because of the transverse IBS. Both transverse and longitudinal IBS can be counteracted with electron cooling. This would allow one to keep the initial peak luminosity close to constant throughout the store essentially without the beam loss. In addition, the phase-space density of the hadron beams can be further increased by providing stronger electron cooling. Unfortunately, the defining limitation for low energies in RHIC is expected to be the space charge. Here we explore an idea of additional improvement in luminosity, on top of the one coming from just IBS compensation and longer stores, which may be expected if one can operate with longer bunches at the space-charge limit in a collider. This approach together with electron cooling may result in about 10-fold improvement in total luminosity for low-energy RHIC program.
Date: February 10, 2012
Creator: A., Fedotov; Blaskiewicz&#44 & M.
Partner: UNT Libraries Government Documents Department
open access

EFFECT OF MELTER-FEED-MAKEUP ON VITRIFICATION PROCESS

Description: Increasing the rate of glass processing in the Hanford Tank Waste Treatment and Immobilization Plant (WTP) will allow shortening the life cycle of waste cleanup at the Hanford Site. While the WTP melters have approached the limit of increasing the rate of melting by enhancing the heat transfer rate from molten glass to the cold cap, a substantial improvement can still be achieved by accelerating the feed-to-glass conversion kinetics. This study investigates how the feed-to-glass conversion process responds to the feed makeup. By identifying the means of control of primary foam formation and silica grain dissolution, it provides data needed for a meaningful and economical design of large-scale experiments aimed at achieving faster melting.
Date: September 10, 2009
Creator: AA, KRUGER; PR, HRMA; MJ, SCHWEIGER; CJ, HUMRICKHOUSE; JA, MOODY; RM, TATE et al.
Partner: UNT Libraries Government Documents Department
open access

Prediction of Coal ash leaching behavior in acid mine water, comparison of laboratory and field studies

Description: Strongly alkaline fluidized bed combustion ash is commonly used to control acid mine drainage in West Virginia coal mines. Objectives include acid neutralization and immobilization of the primary AMD pollutants: iron, aluminum and manganese. The process has been successful in controlling AMD though doubts remain regarding mobilization of other toxic elements present in the ash. In addition, AMD contains many toxic elements in low concentrations. And, each mine produces AMD of widely varying quality. So, predicting the effect of a particular ash on a given coal mine's drainage quality is of particular interest. In this chapter we compare the results of a site-specific ash leaching procedure with two large-scale field applications of FBC ash. The results suggested a high degree of predictability for roughly half of the 25 chemical parameters and poor predictability for the remainder. Of these, seven parameters were successfully predicted on both sites: acidity, Al, B, Ba, Fe, Ni and Zn while electrical conductivity, Ca, Cd, SO4, Pb and Sb were not successfully predicted on either site. Trends for the remaining elements: As, Ag, Be, Cu, Cr, Hg, Mg, Mn, pH, Se Tl and V were successfully predicted on one but not both mine sites.
Date: January 10, 2005
Creator: ANNA, KNOX
Partner: UNT Libraries Government Documents Department
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Environmental tests of the Meteorological Data Acquisition system's remote station

Description: We subjected the Meteorological Data Acquisition (MEDA) remote station hardware to temperature, vibration, and road tests. The MEDA equipment was designed at the Lawrence Livermore Laboratory (LLL) for the Air Resources Laboratory (ARL). ARL supplied all MEDA sensors. The prototype system passed these tests.
Date: May 10, 1976
Creator: Aaron, Jr., C. C.
Partner: UNT Libraries Government Documents Department
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[Studies of non-linear dynamics of dissipative systems]. [Final report, April 1, 1988--October 31, 1989]

Description: In the period of this grant I worked on three main areas: (1) Symmetries in inviscid flow equations in one, two, and three dimensions and related nonlinear stability theorems for these flows; (2) applications of Hamiltonian mechanics to the problems of shallow water equations and internal wave dynamics in oceanic flows; and, (3) analysis of signals from chaotic systems with an eye toward learning how to build models of chaotic systems in nature.
Date: September 10, 1990
Creator: Abarbanel, D. I.
Partner: UNT Libraries Government Documents Department
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(Studies of non-linear dynamics of dissipative systems)

Description: In the period of this grant I worked on three main areas: (1) Symmetries in inviscid flow equations in one, two, and three dimensions and related nonlinear stability theorems for these flows; (2) applications of Hamiltonian mechanics to the problems of shallow water equations and internal wave dynamics in oceanic flows; and, (3) analysis of signals from chaotic systems with an eye toward learning how to build models of chaotic systems in nature.
Date: September 10, 1990
Creator: Abarbanel, D.I.
Partner: UNT Libraries Government Documents Department
open access

Radiative higgs boson decays H {yields} f{anti f}{gamma}

Description: Higgs boson radiative decays of the form H {r_arrow} f{ovr f}{gamma} are calculated in the Standard Model using the complete one-loop expressions for the decay amplitudes. Contributions to the radiative width from leptons and light quarks are given. We also present e{ovr e} invariant mass distributions for H {r_arrow} e{ovr e}{gamma}, which illustrate the importance of the photon pole contribution and the effects of the box diagrams. 4 refs., 6 figs.
Date: October 10, 1996
Creator: Abbasabadi, A.; Bowser-Chao, D.; Repko, W.W. & Dicus, D.A.
Partner: UNT Libraries Government Documents Department
open access

A Preliminary measurement of the gluon splitting rate into b\bar{b} pairs in hadronic Z0 decays

Description: We present a measurement of the rate of gluon splitting into bottom quarks, g --> b anti-b, in hadronic Z<sup>0</sup> decays collected by SLD from 1996 to 1998. The analysis was performed by looking for secondary bottom production in 4-jet events of any primary avor. A topological vertex mass technique was used to tag the two jets with the smallest angle between them as b/anti-b. We obtained a rate of g --> b anti-b per hadronic event to be (3.07 ± 0.71(stat:) ± 0.66(syst:)) × 10&sup3; (preliminary).
Date: June 10, 1999
Creator: Abe, Toshinori
Partner: UNT Libraries Government Documents Department
open access

Electric Reliability: Options for Electric Transmission Infrastructure Improvements

Description: The electric utility industry is inherently capital intensive. At the same time, the industry must operate under a changing and sometimes unpredictable regulatory system at both the federal and state level. The Energy Policy Act of 2005 has set in place government activities intended to relieve congestion on the transmission system. Several factors have contributed to the lack of new transmission capacity; these are outlined within this report. This report also discusses earlier pieces of energy legislation.
Date: June 10, 2005
Creator: Abel, Amy
Partner: UNT Libraries Government Documents Department
open access

[RE: Attached Letter and Invitation List]

Description: Photocopy of a memo from Julie Abel, program associate at the Getty Center for Education in the Arts, to the Regional and California Institute Directors. The memo is in regards to an attached letter and invitation list of invitees to the regional funder's meeting, October 9th, 1993. The letter, dated August 9, 1993, is from Vicki Rosenberg, program officer of the Getty Center for Education in the Arts, to Bob Crow, executive director of the Amon G. Carter Foundation, inviting him to the meeting. The Center is hosting the meeting to recognize the partnerships that have grown over the past five years. Another letter, dated the same and also from Vicki Rosenberg is present, but addressed to Mark Constantine, consultant at Jessie Ball duPont Fund and has the same invitation.
Date: August 10, 1993
Creator: Abel, Julie
Partner: UNT Libraries Special Collections
open access

[RE: Attached Letter and Invitation List]

Description: Photocopy of a memo from Julie Abel, program associate at the Getty Center for Education in the Arts, to the Regional and California Institute Directors. The memo is in regards to an attached letter and invitation list of invitees to the regional funder's meeting, October 9th, 1993. The letter, dated August 9, 1993, is from Vicki Rosenberg, program officer of the Getty Center for Education in the Arts, to Bob Crow, executive director of the Amon G. Carter Foundation, inviting him to the meeting. The Center is hosting the meeting to recognize the partnerships that have grown over the past five years. Another letter, dated the same and also from Vicki Rosenberg is present, but addressed to Mark Constantine, consultant at Jessie Ball duPont Fund and has the same invitation.
Date: August 10, 1993
Creator: Abel, Julie
Partner: UNT Libraries Special Collections
open access

[RE: Questions for November Assessment Meeting, Austin, Texas]

Description: A memo from Julie Abel, program associate of the Getty Center for Education in the Arts, to Jack Davis, Bill McCarter, co-directors of North Texas Institute for Educators on the Visual Arts and Connie Newton. The memo is in regards to questions they sent in prior correspondence for the speakers at the Assessment Meeting in November. However, the questions arrived a week late and were not sent to the speakers. She requests that they bring the questions to the meeting.
Date: October 10, 1989
Creator: Abel, Julie
Partner: UNT Libraries Special Collections
open access

Longitudinal double-spin asymmetry and cross section for inclusivejet production in polarized proton collisions at sqrt(s) = 200 GeV

Description: We report a measurement of the longitudinal double-spinasymmetry A_LL and the differential cross section for inclusivemidrapidity jet production in polarized proton collisions at sqrt(s)=200GeV. The cross section data cover transverse momenta 5<pT<50GeV/c and agree with next-to-leading order perturbative QCD evaluations.The A_LL data cover 5<pT<17 GeV/c and disfavor at 98 percentC.L. maximal positive gluon polarization in the polarizednucleon.
Date: August 10, 2006
Creator: Abelev, B. I.; Adams, J.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
Partner: UNT Libraries Government Documents Department
open access

LIQUID THERMAL DIFFUSION

Description: A revised and expanded version of NNES-DC-1. The liquid thermal diffusion method for the separation of isotopes is described. The discussion includes the experimental aspects of the method, description of equipment, and the theoretical aspects of the process as applied to the design, development, and performance criteria. A short history of the liquid thermal diffusion method from 1940 to 1945 is preserted along; with a survey of relevant literature prior to 1940. The remainder of the report is concerned with theoretical aspects. (J.R.D.)
Date: September 10, 1946
Creator: Abelson, P.H.; Rosen, N. & Hoover, J.I. eds.
Partner: UNT Libraries Government Documents Department
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SEISMIC SOURCE SCALING AND DISCRIMINATION IN DIVERSE TECTONIC ENVIRONMENTS

Description: The objectives of this study are to improve low-magnitude regional seismic discrimination by performing a thorough investigation of earthquake source scaling using diverse, high-quality datasets from varied tectonic regions. Local-to-regional high-frequency discrimination requires an estimate of how earthquakes scale with size. Walter and Taylor (2002) developed the MDAC (Magnitude and Distance Amplitude Corrections) method to empirically account for these effects through regional calibration. The accuracy of these corrections has a direct impact on our ability to identify clandestine explosions in the broad regional areas characterized by low seismicity. Unfortunately our knowledge of source scaling at small magnitudes (i.e., m{sub b} &lt; {approx}4.0) is poorly resolved. It is not clear whether different studies obtain contradictory results because they analyze different earthquakes, or because they use different methods. Even in regions that are well studied, such as test sites or areas of high seismicity, we still rely on empirical scaling relations derived from studies taken from half-way around the world at inter-plate regions. We investigate earthquake sources and scaling from different tectonic settings, comparing direct and coda wave analysis methods. We begin by developing and improving the two different methods, and then in future years we will apply them both to each set of earthquakes. Analysis of locally recorded, direct waves from events is intuitively the simplest way of obtaining accurate source parameters, as these waves have been least affected by travel through the earth. But there are only a limited number of earthquakes that are recorded locally, by sufficient stations to give good azimuthal coverage, and have very closely located smaller earthquakes that can be used as an empirical Green's function (EGF) to remove path effects. In contrast, coda waves average radiation from all directions so single-station records should be adequate, and previous work suggests that the requirements for the EGF …
Date: July 10, 2007
Creator: Abercrombie, R E; Mayeda, K; Walter, W R; Viegas, G M & Murphy, K
Partner: UNT Libraries Government Documents Department
open access

III-Nitride Dry Etching - Comparison of Inductively Coupled Plasma Chemistries

Description: A systematic study of the etch characteristics of GaN, AlN and InN has been performed with boron halides- (BI{sub 3} and BBr{sub 3}) and interhalogen- (ICl and IBr) based Inductively Coupled Plasmas. Maximum etch selectivities of -100:1 were achieved for InN over both GaN and AlN in the BI{sub 3} mixtures due to the relatively high volatility of the InN etch products and the lower bond strength of InN. Maximum selectivies of- 14 for InN over GaN and >25 for InN over AlN were obtained with ICl and IBr chemistries. The etched surface morphologies of GaN in these four mixtures are similar or better than those of the control sample.
Date: November 10, 1998
Creator: Abernathy, C.R.; Cho, H.; Donovan, S.M.; Hahn, Y-B.; Han, J.; Hays, D.C. et al.
Partner: UNT Libraries Government Documents Department
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A novel approach to highly dispersing catalytic materials in coal for gasification. Ninth quarterly report, October 1, 1991--December 31, 1991

Description: This project seeks to develop a technique, based on coal surface properties, for highly dispersing catalysts in coal for gasification and to investigate the potential of using potassium carbonate and calcium acetate mixtures as catalysts for coal gasification. The lower cost and higher catalytic activity of the latter compound will produce economic benefits by reducing the amount of K{sub 2}CO{sub 3} required for high coal char reactivities. As was shown in previous reports, coal loading with potassium or calcium at different pHs produced CO{sub 2} gasification activities which increased in the order pH 6 > pH 10 {much_gt} pH 1. The current report shows that a similar trend was obtained when calcium and potassium were simultaneously loaded and char reaction times were less than about 75 min. Beyond this time, the coal impregnated with catalyst at pH 1 became more reactive, reaching 100% conversion after 1.5h. X-ray diffraction analysis suggest that the catalysts are well dispersed around pH 1 and 6 whereas reduced dispersion as obtained at pH 10. The reactivities are independent of the surface areas of the coals.
Date: February 10, 1992
Creator: Abotsi, G. M. K. & Bota, K. B.
Partner: UNT Libraries Government Documents Department
open access

A novel approach to highly dispersing catalytic materials in coal for gasification

Description: This project seeks to develop a technique, based on coal surface properties, for highly dispersing catalysts in coal for gasification and to investigate the potential of using potassium carbonate and calcium acetate mixtures as catalysts for coal gasification. The lower cost and higher catalytic activity of the latter compound will produce economic benefits by reducing the amount of K{sub 2}CO{sub 3} required for high coal char reactivities. As was shown in previous reports, coal loading with potassium or calcium at different pHs produced CO{sub 2} gasification activities which increased in the order pH 6 > pH 10 {much gt} pH 1. The current report shows that a similar trend was obtained when calcium and potassium were simultaneously loaded and char reaction times were less than about 75 min. Beyond this time, the coal impregnated with catalyst at pH 1 became more reactive, reaching 100% conversion after 1.5h. X-ray diffraction analysis suggest that the catalysts are well dispersed around pH 1 and 6 whereas reduced dispersion as obtained at pH 10. The reactivities are independent of the surface areas of the coals.
Date: February 10, 1992
Creator: Abotsi, G.M.K. & Bota, K.B.
Partner: UNT Libraries Government Documents Department
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