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A 10,000 groove/mm multilayer coated grating for EUV spectroscopy

Description: Ultra-high spectral resolution in the EUV and soft x-ray energy ranges requires the use of very high line density gratings with optimal design resulting in use of a Blazed Multilayer Grating (BMG) structure. Here we demonstrate the production of near-atomically perfect Si blazed substrates with an ultra-high groove density (10,000 l/mm) together with the measured and theoretical performance of an Al/Zr multilayer coating on the grating. A 1st order absolute efficiency of 13percent and 24.6percent was achieved at incidence angles of 11o and 36o respectively. Cross-sectional TEM shows the effect of smoothing caused by the surface mobility of deposited atoms and we correlate this effect with a reduction in peak diffraction efficiency. This work shows the high performance that can be achieved with BMGs based on small-period anisotropic etched Si substrates, but also the constraints imposed by the surface mobility of deposited species.
Date: February 7, 2011
Creator: Voronov, Dmytro; Anderson, Erik; Cambie, Rossana; Cabrini, Stefano; Dhuey, Scott; Goray, Leonid et al.
Partner: UNT Libraries Government Documents Department

1996 Central New Mexico Section [American Chemical Society] annual report

Description: The main goal of the Central New Mexico Section this year was to increase attendance at the local meetings. Throughout the course of the year attendance at the meeting more than doubled. This was brought on by several factors: having the meeting spread throughout the section (Albuquerque, Santa Fe, Las Vegas, Socorro, Los Alamos); supplementing the ACS National Tour speakers with interesting local sections speakers; and making full use of the newly formed Public Relations Committee. Activities during 1996 are summarized.
Date: February 7, 1997
Creator: Cournoyer, M.E.
Partner: UNT Libraries Government Documents Department

A 3D Model for Ion Beam Formation and Transport Simulation

Description: In this paper, we present a three-dimensional model forself-consistently modeling ion beam formation from plasma ion sources andtransporting in low energy beam transport systems. A multi-sectionoverlapped computational domain has been used to break the originaltransport system into a number of weakly coupled subsystems. Within eachsubsystem, macro-particle tracking is used to obtain the charge densitydistribution in this subdomain. The three-dimensional Poisson equation issolved within the subdomain after each particle tracking to obtain theself-consistent space-charge forces and the particle tracking is repeateduntil the solution converges. Two new Poisson solvers based on acombination of the spectral method and the finite difference multigridmethod have been developed to solve the Poisson equation in cylindricalcoordinates for the straight beam transport section and in Frenet-Serretcoordinates for the bending magnet section. This model can have importantapplication in design and optimization of the low energy beam line opticsof the proposed Rare Isotope Accelerator (RIA) front end.
Date: February 7, 2006
Creator: Qiang, J.; Todd, D. & Leitner, D.
Partner: UNT Libraries Government Documents Department

Accurate Astrometry and Photometry of Saturated and Coronagraphic Point Spread Functions

Description: For ground-based adaptive optics point source imaging, differential atmospheric refraction and flexure introduce a small drift of the point spread function (PSF) with time, and seeing and sky transmission variations modify the PSF flux. These effects need to be corrected to properly combine the images and obtain optimal signal-to-noise ratios, accurate relative astrometry and photometry of detected companions as well as precise detection limits. Usually, one can easily correct for these effects by using the PSF core, but this is impossible when high dynamic range observing techniques are used, like coronagraphy with a non-transmissive occulting mask, or if the stellar PSF core is saturated. We present a new technique that can solve these issues by using off-axis satellite PSFs produced by a periodic amplitude or phase mask conjugated to a pupil plane. It will be shown that these satellite PSFs track precisely the PSF position, its Strehl ratio and its intensity and can thus be used to register and to flux normalize the PSF. This approach can be easily implemented in existing adaptive optics instruments and should be considered for future extreme adaptive optics coronagraph instruments and in high-contrast imaging space observatories.
Date: February 7, 2006
Creator: Marois, C; Lafreniere, D; Macintosh, B & Doyon, R
Partner: UNT Libraries Government Documents Department

Actinide halide complexes

Description: A compound of the formula MX{sub n}L{sub m} wherein M = Th, Pu, Np,or Am thorium, X = a halide atom, n = 3 or 4, L is a coordinating ligand selected from the group consisting of aprotic Lewis bases having an oxygen-, nitrogen-, sulfur-, or phosphorus-donor, and m is 3 or 4 for monodentate ligands or is 2 for bidentate ligands, where n + m = 7 or 8 for monodentate ligands or 5 or 6 for bidentate ligands, a compound of the formula MX{sub n} wherein M, X, and n are as previously defined, and a process of preparing such actinide metal compounds including admixing the actinide metal in an aprotic Lewis base as a coordinating solvent in the presence of a halogen-containing oxidant, are provided.
Date: February 7, 1991
Creator: Avens, Larry R.; Zwick, Bill D.; Sattelberger, Alfred P.; Clark, David L. & Watkin, J. G.
Partner: UNT Libraries Government Documents Department

An Action Plan for the Restructuring and Rationalization of the National Intercity Rail Passanger System

Description: Final report of the Amtrak Reform Council describing their activities and findings regarding the Council's proposed action plan for restructuring the national intercity rail passenger system in the face of Amtrak's failure to achieve operational self-sufficiency.
Date: February 7, 2002
Creator: Amtrak Reform Council
Partner: UNT Libraries Government Documents Department

Advanced direct coal liquefaction. Quarterly technical progress report No. 1, September-November 1983

Description: Wyoming subbituminous coal was liquefied using three different two-stage process configurations in bench-scale tests. These process configurations differed in the type of fractionated deashing resid being recycled to the individual stages. The objective of these runs was to determine whether, by recycle of specific resid streams to the thermal stage, the second stage catalyst life could be improved without detrimentally affecting distillate yield or hydrogen consumption. The results indicate that the two-stage process configuration consisting of hydrotreating the Light Deashed Resid and direct recycle of heavy Deashed Resid to the thermal stage produced the best results. This process configuration resulted in a distillate yield of 54 wt % (MAF coal basis) and overall coal conversion in the 93 to 95% range, as measured by pyridine-soluble analytical test while operating in a total distillate mode. These results are very encouraging from the lower rank Wyoming subbituminous coal. Among the three two-stage process configurations tested, the particular process configuration of hydrotreating Light Deashed Resid resulted in the least amount of catalyst deactivation. As a part of this research effort, a test procedure for quick evaluation of various resids and catalysts in terms of coke precursors was also developed. This procedure utilizing as-produced oxide-form extrudates of catalyst is able to simulate closely in a batch reactor test the performance of a presulfided and extrudate form of catalyst in a continuous reactor. The CSD unit, being able to not only deash but also fractionate the resid, greatly increased the flexibility of options for coal liquefaction. New process concepts evolved incorporating reside fractionation and selective resid recycle in coal liquefaction. 17 figures, 28 tables.
Date: February 7, 1984
Creator: Paranjape, A.S.
Partner: UNT Libraries Government Documents Department

Advances in Parallel Electromagnetic Codes for Accelerator Science and Development

Description: Over a decade of concerted effort in code development for accelerator applications has resulted in a new set of electromagnetic codes which are based on higher-order finite elements for superior geometry fidelity and better solution accuracy. SLAC's ACE3P code suite is designed to harness the power of massively parallel computers to tackle large complex problems with the increased memory and solve them at greater speed. The US DOE supports the computational science R&D under the SciDAC project to improve the scalability of ACE3P, and provides the high performance computing resources needed for the applications. This paper summarizes the advances in the ACE3P set of codes, explains the capabilities of the modules, and presents results from selected applications covering a range of problems in accelerator science and development important to the Office of Science.
Date: February 7, 2011
Creator: Ko, Kwok; Candel, Arno; Ge, Lixin; Kabel, Andreas; Lee, Rich; Li, Zenghai et al.
Partner: UNT Libraries Government Documents Department

Aerodynamic Characteristics of a 0.04956-Scale Model of the Convair F-102B Airplane at Mach Numbers of 1.41, 1.61, and 2.01: Coord No. AF-231

Description: Report discussing testing of a scale model of the Convair F-102B to determine its aerodynamic characteristics at several Mach numbers. Four basic body modifications and two afterbody configurations were evaluated.The body modifications were all found to slightly reduce values of minimum drag, but did not cause a change in the static stability and lift-curve-slope values compared to the F-102A.
Date: February 7, 1956
Creator: Driver, Cornelius & Robinson, Ross B.
Partner: UNT Libraries Government Documents Department

The Aerodynamic Forces and Moments Exerted on a Spinning Model of the NY-1 Airplane as Measured by the Spinning Balance

Description: From Summary: "A preliminary investigation of the effects of changes in the elevator and rudder settings and of small changes in attitude upon the aerodynamic forces and moments exerted upon a spinning airplane was undertaken with the spinning balance in the 5-foot vertical tunnel of the National Advisory Committee for Aeronautics. The tests were made on a 1/12-scale model of the "NY-1" airplane. Data by which to fix the attitude, the radius of spin, and the rotational and air velocities were taken from recorded spins of the full-scale airplane."
Date: February 7, 1933
Creator: Bamber, M. J. & Zimmerman, C. H.
Partner: UNT Libraries Government Documents Department

Aerometric measurement and modeling of the mass of CO2 emissions from Crystal Geyser, Utah

Description: Crystal Geyser in eastern Utah is a rare, non-geothermal geyser that emits carbon dioxide gas in periodic eruptions. This geyser is the largest single source of CO{sub 2} originating from a deep reservoir. For this study, the amount of CO{sub 2} emitted from Crystal Geyser is estimated through measurements of downwind CO{sub 2} air concentration applied to an analytical model for atmospheric dispersion. Five eruptions occurred during the 48-hour field study, for a total of almost 3 hours of eruption. Pre-eruption emissions were also timed and sampled. Slow wind during three of the active eruptions conveyed the plume over a grid of samplers arranged in arcs from 25 to 100 m away from the geyser. An analytical, straight-line Gaussian model matched the pattern of concentration measurements. Plume width was determined from least-squares fit of the CO{sub 2} concentrations integrated over time. The CO{sub 2} emission rate was found to be between 2.6 and 5.8 kg/s during the eruption events, and about 0.17 kg/s during the active pre-eruptive events. Our limited field study can be extrapolated to an annual CO{sub 2} emission of 12 kilotonnes from this geyser. As this is the first application of Gaussian dispersion modeling and objective timing to CO{sub 2} emissions from a geyser of any type, the present study demonstrates the feasibility of applying this method more completely in the future.
Date: February 7, 2005
Creator: Gouveia, F J; Johnson, M R; Leif, R N & Friedmann, S J
Partner: UNT Libraries Government Documents Department

An Aerosol Condensation Model for Sulfur Trioxide

Description: This document describes a model for condensation of sulfuric acid aerosol given an initial concentration and/or source of gaseous sulfur trioxide (e.g. fuming from oleum). The model includes the thermochemical effects on aerosol condensation and air parcel buoyancy. Condensation is assumed to occur heterogeneously onto a preexisting background aerosol distribution. The model development is both a revisiting of research initially presented at the Fall 2001 American Geophysical Union Meeting [1] and a further extension to provide new capabilities for current atmospheric dispersion modeling efforts [2]. Sulfuric acid is one of the most widely used of all industrial chemicals. In 1992, world consumption of sulfuric acid was 145 million metric tons, with 42.4 Mt (mega-tons) consumed in the United States [10]. In 2001, of 37.5 Mt consumed in the U.S., 74% went into producing phosphate fertilizers [11]. Another significant use is in mining industries. Lawuyi and Fingas [7] estimate that, in 1996, 68% of use was for fertilizers and 5.8% was for mining. They note that H{sub 2}SO{sub 4} use has been and should continue to be very stable. In the United States, the elimination of MTBE (methyl tertiary-butyl ether) and the use of ethanol for gasoline production are further increasing the demand for petroleum alkylate. Alkylate producers have a choice of either a hydrofluoric acid or sulfuric acid process. Both processes are widely used today. Concerns, however, over the safety or potential regulation of hydrofluoric acid are likely to result in most of the growth being for the sulfuric acid process, further increasing demand [11]. The implication of sulfuric acid being a pervasive industrial chemical is that transport is also pervasive. Often, this is in the form of oleum tankers, having around 30% free sulfur trioxide. Although sulfuric acid itself is not a volatile substance, fuming sulfuric acid (referred to ...
Date: February 7, 2008
Creator: Grant, K E
Partner: UNT Libraries Government Documents Department


Description: This plan provides an overview, work to date, and the path forward for the design development strategy of the Aging cask for aging commercial spent nuclear fuel (CSNF) at the Yucca Mountain Project (YMP) repository site. Waste for subsurface emplacement at the repository includes US Department of Energy (DOE) high-level radioactive waste (HLW), DOE SNF, commercial fuel in dual-purpose canisters (DPCs), uncanistered bare fuel, naval fuel, and other waste types. Table 1-1 lists the types of radioactive materials that may be aged at YMP, and those materials that will not be placed in an aging cask or module. This plan presents the strategy for design development of the Aging system. The Aging system will not handle naval fuel, DOE HLW, MCOs, or DOE SNF since those materials will be delivered to the repository in a state and sequence that allows them to be placed into waste packages for emplacement. Some CSNF from nuclear reactors, especially CSNF that is thermally too hot for emplacement underground, will need to be aged at the repository.
Date: February 7, 2005
Creator: Beesley, J.
Partner: UNT Libraries Government Documents Department

Air Force and Interior Can Benefit from Additional Guidance When Deciding Whether to Lease or Purchase Equipment

Description: Correspondence issued by the Government Accountability Office with an abstract that begins "Contracting officials from Air Force and Interior generally did not perform lease versus purchase analyses for selected contracts. Based on contract file reviews and discussions with contracting officials, we found that analyses were not performed and that contracting officials had not considered the alternative acquisition method for 24 of the 32 selected contracts. For the 8 contracts with lease versus purchase analyses, 5 were documented in the contract files and 3 were performed but were not documented, according to contracting officials. In most cases, contract files did not contain basic information to make lease or purchase decisions, such as the length of time the equipment would be used. Even files containing documentation of analyses generally did not address the full range of criteria specified in the FAR. For example, the analyses typically lacked a discussion of the financial and operating advantages of alternate approaches that would help contracting officials determine the appropriate acquisition method. Contracting officials noted that their decision to lease or purchase equipment often depends on the nature of the requirement, such as a short-term need for equipment, based on documents or other correspondence from the requester. Further, these officials generally stated that while they are familiar with the FAR guidance, they typically do not know how or when to perform the analyses and are not provided training on how to do so."
Date: February 7, 2012
Creator: United States. Government Accountability Office.
Partner: UNT Libraries Government Documents Department

Airline Competition: Issues Raised by Consolidation Proposals

Description: A statement of record issued by the General Accounting Office with an abstract that begins "In May 2000, United Airlines proposed to acquire US Airways and divest part of those assets to create a new airline to be called DC Air. More recently, American Airlines has proposed buying Trans World Airlines (TWA), along with certain assets from United. These proposals have raised questions about how such consolidation in the airline industry could affect competition in general and consumers in particular. Congress, the Department of Justice, and the Department of Transportation need to answer several questions in evaluating the proposed mergers. The proposals by American, TWA, United, US Airways, and DC Air constitute the most significant recent changes that have occured in the airline industry, and the outcome of these decisions could have both positive and negative effects for consumers for years to come. This testimony summarized a December GAO report (GAO-01-212)."
Date: February 7, 2001
Creator: United States. General Accounting Office.
Partner: UNT Libraries Government Documents Department

Airport Improvement Program

Description: This issue brief discusses the Airport Improvement Program and its complement, the Passenger Facility Charge (PFC). After a brief history of federal support for airport construction and improvement, the report describes AIP funding, its source of revenues, funding distribution, the types of projects the program funds, AIP and PFC policy issues, and the allowable use of AIP funds for airport security purposes.
Date: February 7, 2003
Creator: Kirk, Robert S.
Partner: UNT Libraries Government Documents Department

[Alfred Hurley portrait]

Description: Photograph of Alfred Hurley sitting for a portrait. He is wearing a dark suit and red and blue tie.
Date: February 7, 2005
Creator: University of North Texas. University Relations, Communications and Marketing.
Partner: UNT Libraries Special Collections

Allied Program Areas and Specializations within LIS: UNT Experience

Description: This presentation was presented as part of a panel on "The Benefits and Challenges of Allied Programs and Specializations in LIS Units" as part of the opening plenary panel at the 2018 Association for Library and Information Science Education (ALISE) Conference. This presentation discusses the rewards and challenges of Library and Information Science (LIS) programs, with a detailed overview of LIS programs offered at the University of North Texas.
Date: February 7, 2018
Creator: Hawamdeh, Suliman M.
Partner: UNT College of Information

Analysis of DOE Spent Nuclear Fuels for Repository Disposal

Description: U.S. Department of Energy (DOE) spent nuclear fuel (SNF) consists of hundreds of different fuel types in various conditions. In order to analyze and model the DOE SNF for its suitability for repository disposal, several generalizations and simplifications were necessary. This paper describes the methodology used to arrive at a suitable DOE SNF surrogate and summarizes the proposed analysis of this DOE SNF surrogate for its appropriateness as a representative SNF.
Date: February 7, 2006
Creator: Pincock, L.F.; Hintze, W.D. & Duguid, J.
Partner: UNT Libraries Government Documents Department

Anti-Tax-Shelter and Other Revenue-Raising Tax Proposals Considered in the 108th Congress

Description: Several bills introduced in the 108th Congress included revenue-raising provisions, particularly those aimed at tax shelters that are generally used by corporations. In 2003, anti-sheltering provisions were included in several bills. This report is an overview of the revenue-raising provisions in the original reported versions of H.R. 2896 and S. 1637 and the final anti-sheltering bill as enacted.
Date: February 7, 2005
Creator: Gravelle, Jane G.
Partner: UNT Libraries Government Documents Department