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Detailed spectroscopic analysis of SN 1987A: The distance to the LMC using the SEAM method
Supernova 1987A remains the most well-studied supernova to date. Observations produced excellent broad-band photometric and spectroscopic coverage over a wide wavelength range at all epochs. We model the observed spectra from Day 1 to Day 81 using a hydrodynamical model. We show that good agreement can be obtained at times up to about 60 days, if we allow for extended nickel mixing. Later than about 60 days the observed Balmer lines become stronger than our models can reproduce. We show that this is likely due to a more complicated distribution of gamma-rays than we allow for in our spherically symmetric calculations. We present synthetic light curves in UBVRIJHK and a synthetic bolometric light curve. Using this broad baseline of detailed spectroscopic models we find a distance modulus mu = 18.5 +/- 0.2 using the SEAM method of determining distances to supernovae. We find that the explosion time agrees with that of the neutrino burst and is constrained at 68 percent confidence to within +/- 0.9 days. We argue that the weak Balmer lines of our detailed model calculations casts doubt on the accuracy of the purely photometric EPM method. We also suggest that Type IIP supernovae will be most useful …
Date:
May 21, 2002
Creator:
Mitchell, Robert C.; Baron, E.; Branch, David; Hauschildt, Peter H.; Nugent, Peter E.; Lundqvist, Peter et al.
Object Type:
Article
System:
The UNT Digital Library
Development and application of NDE methods for monolithic and continuous fiber ceramic matrix composites.
Monolithic structural ceramics and continuous fiber ceramic matrix composites (CMCs) are being developed for application in many thermally and chemically aggressive environments where structural reliability is paramount. We have recently developed advanced nondestructive evaluation (NDE) methods that can detect distributed ''defects'' such as density gradients and machining-induced damage in monolithic materials, as well as delamination, porosity, and throughwall cracks, in CMC materials. These advanced NDE methods utilize (a) high-resolution, high-sensitivity thermal imaging; (b) high-resolution X-ray imaging; (c) laser-based elastic optical scattering; (d) acoustic resonance; (e) air-coupled ultrasonic methods; and (f) high-sensitivity fluorescent penetrant technology. This paper discusses the development and application of these NDE methods relative to ceramic processing and ceramic components used in large-scale industrial gas turbines and hot gas filters for gas stream particulate cleanup.
Date:
May 21, 1999
Creator:
Ellingson, W. A.
Object Type:
Article
System:
The UNT Digital Library
Development and evaluation of radon sealants for uranium mines
None
Date:
May 21, 1975
Creator:
Hammon, H.G.; Ernst, K.; Gaskill, J.R.; Newton, J.C. & Morris, C.J.
Object Type:
Report
System:
The UNT Digital Library
Development of a Spatially Resolving X-Ray Crystal Spectrometer (XCS) for Measurement of Ion-Temperature (Ti) and Rotation-Velocity (v) Profiles in ITER
Imaging XCS arrays are being developed as a US-ITER activity for Doppler measurement of Ti and v profiles of impurities (W, Kr, Fe) with ~7 cm (a/30) and 10-100 ms resolution in ITER. The imaging XCS, modeled after a PPPL-MIT instrument on Alcator C-Mod, uses a spherically bent crystal and 2d x-ray detectors to achieve high spectral resolving power (E/dE>6000) horizontally and spatial imaging vertically. Two arrays will measure Ti and both poloidal and toroidal rotation velocity profiles. Measurement of many spatial chords permits tomographic inversion for inference of local parameters. The instrument design, predictions of performance, and results from C-Mod will be presented.
Date:
May 21, 2010
Creator:
Hill, K. W.; Delgado-Aprico, L.; Johnson, D.; Feder, R.; Beiersdorfer, P.; Dunn, J. et al.
Object Type:
Report
System:
The UNT Digital Library
Development of advanced direct perception displays for nuclear power plants to enhance monitoring, control and fault management. Progress report
With recent theoretical and empirical research in basic and applied psychology, human factors, and engineering, it is now sufficient to define an integrated approach to the deign of advanced displays for present and future nuclear power plants. Traditionally, the conventional displays have shown operators the individual variables on gauges, meters, strip charts, etc. This design approach requires the operators to mentally integrate the separately displayed variables and determine the implications for the plant state. This traditional approach has been known as the single-sensor-single-indicator display design and it places an intolerable amount of mental workload on operators during transients and abnormal conditions. This report discusses a new alternative approach which is the use of direct perception interfaces. Direct perception a interfaces display the underlying physical and system constraints of the situation in a directly perceptual way, such that the viewer need not reason about what is seen to identify system states, but can identify the state of the system perceptually. It is expected that displays which show the dynamics of fundamental physical laws should better support operator decisions and diagnoses of plant states. The purpose of this research project is to develop a suite of direct perception displays for PWR nuclear …
Date:
May 21, 1993
Creator:
Jones, B.; Shaheen, S.; Moray, N.; Sanderson, P. & Reising, D. V.
Object Type:
Report
System:
The UNT Digital Library
Development of extreme ultraviolet and soft x-ray multilayer optics for scientific studies with femtosecond/attosecond sources
The development of multilayer optics for extreme ultraviolet (EUV) radiation has led to advancements in many areas of science and technology, including materials studies, EUV lithography, water window microscopy, plasma imaging, and orbiting solar physics imaging. Recent developments in femtosecond and attosecond EUV pulse generation from sources such as high harmonic generation lasers, combined with the elemental and chemical specificity provided by EUV radiation, are opening new opportunities to study fundamental dynamic processes in materials. Critical to these efforts is the design and fabrication of multilayer optics to transport, focus, shape and image these ultra-fast pulses This thesis describes the design, fabrication, characterization, and application of multilayer optics for EUV femtosecond and attosecond scientific studies. Multilayer mirrors for bandwidth control, pulse shaping and compression, tri-material multilayers, and multilayers for polarization control are described. Characterization of multilayer optics, including measurement of material optical constants, reflectivity of multilayer mirrors, and metrology of reflected phases of the multilayer, which is critical to maintaining pulse size and shape, were performed. Two applications of these multilayer mirrors are detailed in the thesis. In the first application, broad bandwidth multilayers were used to characterize and measure sub-100 attosecond pulses from a high harmonic generation source and …
Date:
May 21, 2009
Creator:
Aquila, Andrew Lee
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Development of Techniques for Power Production From Mixed Fission Products
"Progress is reported on Phase II of a program for the development of a mixed fission product fueled thermoelectric generator. Materials studies are described in which bonded assemblies of bismuth telluride were life tested up to 3000 hours at 350 to 400 deg F hot junction temperature. Data were too inconsistent to define any satisfactory long-life bonding process. Further work is needed to eliminate the process variables. Insulation studies aimed at determining the thermal conductivity of various insulations with different fill gases under reduced pressures are described. Opacified aerogel powder appears to be very promising as an insulation medium for a diffuse heat source. A full- scale simulated test generator aimed at proving out the concept of a diffuse heat source for power generation is described. Progress on the construction of this electrically heated generator and its thermoelectric power converter is related.
Date:
May 21, 1962
Creator:
Lemanski, E. J.
Object Type:
Report
System:
The UNT Digital Library
Development of the Amex process for americium recovery
None
Date:
May 21, 1954
Creator:
Rainey, R.H.
Object Type:
Report
System:
The UNT Digital Library
Differential Construction
Patent for "a new and Improved Differential Construction" (lines 5-6). "The object of the present invention is to provide a differential particularly suitable for motor vehicles... whereby the spinning of the wheels... is effectually prevented while the relative movement thereof necessary in passing around curves is freely allowed" (lines 22-31).
Date:
May 21, 1919
Creator:
Reagan, Edgar U. G.
Object Type:
Patent
System:
The Portal to Texas History
Direct catalytic conversion of methane and light hydrocarbon gases. Quarterly report No. 2, January 16, 1987--April 15, 1987
The goal of this research is to develop catalysts that directly convert methane and light hydrocarbons to intermediates that can, as economics dictate, be subsequently converted either to liquid fuels or value-added chemicals. In this program we are exploring two approaches to developing such catalysts. The first approach consists of developing advanced catalysts for reforming methane. We will prepare the catalysts by reacting organometallic complexes of transition metals (Fe, Ru, Rh, and Re) with zeolitic and rare-earth-exchanged zeolitic supports to produce surfaceconfined metal complexes in the zeolite pores. Our second approach entails synthesizing the porphyrin and phthalocyanine complexes of Cr, Mn, Ru, Fe, and/or Co within the pores of zeolitic supports for use as selective oxidation catalysts for methane and light hydrocarbons. During the second quarter of this project, we concentrated on methane reforming. Two ruthenium clusters (Ru{sub 4} and Ru{sub 6}) supported on three types of support materials ({beta}-alumina, 5 {Angstrom} molecular sieves, and {gamma}-zeolite) were tested for methane reforming. The effects of cluster size, supporting material, and reaction conditions were evaluated. The methane conversions range from 1.74 to 10.11% at 750{degrees}C. The reaction product contains hydrogen, C{sub 2} hydrocarbons, and C{sub 6} or higher hydrocarbons. Up to 48.34% …
Date:
May 21, 1987
Creator:
Wilson, R. B., Jr. & Chan, Yee Wai
Object Type:
Report
System:
The UNT Digital Library
Direct Wind Superconducting Corrector Magnets for the SUPERKEKB IR
N/A
Date:
May 21, 2012
Creator:
B., Parker; Anerella, M.; Escallier, J.; Ghosh, A.; Jain, A.; Marone, A. et al.
Object Type:
Article
System:
The UNT Digital Library
DISPOSAL OF REACTOR DEIONIZER VESSELS HIGHLY CONTAMINATED WITH 14 CARBON IN THE INTERMEDIATE LEVEL VAULT FACILITY AT SRS
At the Savannah River Site (SRS), nuclear production reactors used deionizers to control the chemistry of the reactor moderator during their operation to produce nuclear materials primarily for the weapons program. These deionizers were removed from the reactors and stored as a legacy waste with no path to disposal due to the relatively high {sup 14}C contamination (i.e., on the order of 20 curies per deionizer for 48-50 deionizers) and the low disposal limit of 4.2 Ci previously established for the Intermediate Level Vault (ILV). The ILV is considered most appropriate facility within which to dispose these items due to the method of solidifying waste items with cementitious material inside concrete vaults. In previous analyses the {sup 14}C ILV disposal limit was established at 4.2 Ci resulting from the use of a very conservative method to analyze the dose received from atmospheric releases of gaseous {sup 14}C. This investigation implemented a more rigorous evaluation of the physical and chemical processes influencing the release and migration of gaseous {sup 14}C (as CO{sub 2}) to obtain a more realistic estimate of atmospheric dose and to determine new ILV disposal limits.
Date:
May 21, 2007
Creator:
Hiergesell, R. & Daniel Kaplan, D.
Object Type:
Article
System:
The UNT Digital Library
DOE-EPSCoR Award. Final Report
This research has led to an understanding of the microscopic processes that are responsible for manipulation of atoms on metal surfaces.
Date:
May 21, 2004
Creator:
Rahman, Talat S.
Object Type:
Report
System:
The UNT Digital Library
Drain-Valve for Well-Pipes.
Patent for drain valves used with well pipes that is "adapted to be positioned in the stand pipe of a well below the surface of the ground, and which may be actuated in cold weather so as to permit of the water in the pipe being drained back into the well" (lines 13-18) including illustration.
Date:
May 21, 1918
Creator:
Lindsey, William Noal
Object Type:
Patent
System:
The Portal to Texas History
Drying Kiln
Patent for a kiln to be used as a drying chamber for drying and curing of lumber. Illustrations included.
Date:
May 21, 1907
Creator:
Stephens, William E.
Object Type:
Patent
System:
The Portal to Texas History
Dynamic Void Fraction Detector
None
Date:
May 21, 1962
Creator:
Kendron, J. H.
Object Type:
Report
System:
The UNT Digital Library
Dynamics of Longitudinal Phase-Space Modulations in an rf Compressor for Electron Beams
Free Electron Lasers (FELs) operating in the UV or x-ray radiation spectrum require peak beam currents that are generally higher than those obtainable by present electron sources, thus making bunch compression necessary. Compression, however, may heighten the effects of collective forces and degrade the beam quality. In this paper they provide a framework for investigating some of these effects in rf compressors by focusing on the longitudinal dynamics of small-amplitude density perturbations, which have the potential to cause the disruptive appearance of the so-called microbunching instability. They develop a linear theory valid for low-to-moderate compression factors under the assumption of a 1D impedance model of longitudinal space charge and provide validation against macroparticle simulations.
Date:
May 21, 2010
Creator:
Venturini, M.; Migliorati, M.; Ronsivalle, C.; Ferrario, M. & Vaccarezza, C.
Object Type:
Article
System:
The UNT Digital Library
Earmark Disclosure Rules in the House: Member and Committee Requirements
This report outlines the major administrative responsibilities of Members and committees of the House of Representatives associated with the chamber's earmark disclosure rules. Earmark disclosure rules in both the House and Senate were implemented with the stated intention of bringing more transparency to congressionally directed spending. The administrative responsibilities associated with these rules vary by chamber.
Date:
May 21, 2015
Creator:
Lynch, Megan S.
Object Type:
Report
System:
The UNT Digital Library
Earmark Disclosure Rules in the Senate: Member and Committee Requirements
This report is categorized into five categories: (I) Introduction, (II) Senate Earmark Disclosure Rule, (III) Legislation Subject to the Rule, (IV) Requirement for Senators Submitting Earmark Requests and (V) Requirements for Committees.
Date:
May 21, 2015
Creator:
Lynch, Megan S.
Object Type:
Report
System:
The UNT Digital Library
Ecuador: Political and Economic Situation and U.S. Relations
Ecuador has experienced ten years of political and economic instability. On January 15, 2007, Rafael Correa, a left-leaning, U.S.-trained economics, was inaugurated to a four-year presidential term, becoming the country's eighth president in ten years. President Correa has fulfilled his campaign pledge to call a constituent assembly to reform the country's constitution. U.S. officials have expressed concerns about President Correa's ties with Hugo Chavez of Venezuela and his stated policies on trade and energy matters. Despite those concerns, Congress enacted legislation in February 2008 to extend U.S. trade preferences for Ecuador through December 2008.
Date:
May 21, 2008
Creator:
Seelke, Clare Ribando
Object Type:
Report
System:
The UNT Digital Library
Effect of Hydrogen on Work Hardening of Type 304L Austenitic Stainless Steel
The grain size and strain dependence of work hardening in Type 304L stainless steel were analyzed between 200 and 250 K where hydrogen damage is greatest. Tensile data were obtained for specimens of several grain sizes, both with and without prior exposure to hydrogen gas at 69 MPa pressure. The analysis suggests that hydrogen has little influence on lattice friction stress but has a large effect on dislocation interaction and the back stress of dislocation pileups. This report discusses this study.
Date:
May 21, 1981
Creator:
Caskey, G. R., Jr.
Object Type:
Article
System:
The UNT Digital Library
EFFECT OF TRANSPORTING SALTSTONE SAMPLES PRIOR TO SET
The Saltstone Sampling and Analyses Plan provides a basis for the quantity (and configuration) of saltstone grout samples required for conducting a study directed towards correlation of the Performance Assessment (PA) related properties of field-emplaced samples and samples processed and cured in the laboratory. The testing described in the saltstone sampling and analyses plan will be addressed in phases. The initial testing (Phase I) includes collecting samples from the process room in the Saltstone Production Facility (SPF) and transporting them to Savannah River National Laboratory (SRNL) where they will cure under a temperature profile that mimics the temperature in the Saltstone Disposal Unit (SDU) and then be analyzed. SRNL has previously recommended that after the samples of fresh (uncured) saltstone are obtained from the SPF process room, they are allowed to set prior to transporting them to SRNL for curing. The concern was that if the samples are transported before they are set, the vibrations during transport may cause artificial delay of structure development which could result in preferential settling or segregation of the saltstone slurry. However, the results of this testing showed there was no clear distinction between the densities of the cylinder sections for any of the transportation …
Date:
May 21, 2013
Creator:
Reigel, M.
Object Type:
Report
System:
The UNT Digital Library
The effects of neutron irradiation on fracture toughness of austenitic stainless steels.
Austenitic stainless steels are used extensively as structural alloys in reactor pressure vessel internal components because of their superior fracture toughness properties. However, exposure to high levels of neutron irradiation for extended periods leads to significant reduction in the fracture resistance of these steels. This paper presents results of fracture toughness J-R curve tests on four heats of Type 304 stainless steel that were irradiated to fluence levels of {approx}0.3 and 0.9 x 10{sup 21} n cm{sup {minus}2} (E >1 MeV) at {approx}288 C in a helium environment in the Halden heavy water boiling reactor. The tests were performed on 1/4-T compact tension specimens in air at 288 C; crack extensions were determined by both DC potential and elastic unloading compliance techniques.
Date:
May 21, 1999
Creator:
Chopra, O. K.; Gruber, E. E. & Shack, W. J.
Object Type:
Article
System:
The UNT Digital Library
Efficient CO2 Fixation Pathways
Advanced Research Projects Agency-Energy project sheet summarizing general information about the Plants Engineered to Replace Oil (PETRO) program including critical needs, innovation and advantages, impacts, and contact information. This sheet discusses a project to make plants more efficient at capturing energy through an alternative biochemical pathway as part of the "Energy Plant: High Efficiency Photosynthetic Organisms" project.
Date:
May 21, 2012
Creator:
University of California, Los Angeles
Object Type:
Text
System:
The UNT Digital Library