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HYBRIDIZATION AND PRESSURE EFFECTS IN UTX COMPOUNDS
None
Date:
October 1, 2001
Creator:
ALSAMDI, A.; SECHOVSKY, V. & AL, ET
Object Type:
Article
System:
The UNT Digital Library
Underground Corrosion of Activated Metals in an Arid Vadose Zone Environment
The subsurface radioactive disposal site located at the Idaho National Engineering and Environmental Laboratory contains neutron-activated metals from nonfuel nuclear-reactor- core components. A long-term corrosion test is being conducted to obtain site-specific corrosion rates to support efforts to more accurately estimate the transfer of activated elements in an arid vadose zone environment. The tests use nonradioactive metal coupons representing the prominent neutron-activated material buried at the disposal location, namely, Type 304L stainless steel, Type 315L stainless steel, nickel-chromium alloy (UNS NO7718), beryllium, aluminum 6061-T6, and a zirconium alloy, (UNS R60804). In addition, carbon steel (the material presently used in the cask disposal liners and other disposal containers) and a duplex stainless steel (UNS S32550) (the proposed material for the high- integrity disposal containers) are also included in the test program. This paper briefly describes the test program and presents the early corrosion rate results after 1 year and 3 years of underground exposure.
Date:
October 24, 2001
Creator:
Adler Flitton, M. K.; Mizia, R. E. & Bishop, C. W.
Object Type:
Article
System:
The UNT Digital Library
Unsaturated Zone Flow Patterns and Analysis
This Analysis/Model Report (AMR) documents the development of an expected-case model for unsaturated zone (UZ) flow and transport that will be described in terms of the representativeness of models of the natural system. The expected-case model will provide an evaluation of the effectiveness of the natural barriers, assess the impact of conservatism in the Total System Performance Assessment (TSPA), and support the development of further models and analyses for public confidence building. The present models used in ''Total System Performance Assessment for the Site Recommendation'' (Civilian Radioactive Waste Management System Management and Operating Contractor (CRWMS M&O) 2000 [1532461]) underestimate the natural-barrier performance because of conservative assumptions and parameters and do not adequately address uncertainty and alternative models. The development of an expected case model for the UZ natural barrier addresses issues regarding flow-pattern analysis and modeling that had previously been treated conservatively. This is in line with the Repository Safety Strategy (RSS) philosophy of treating conservatively those aspects of the UZ flow and transport system that are not important for achieving regulatory dose (CRWMS M&O 2000 [153246], Section 1.1.1). The development of an expected case model for the UZ also provides defense-in-depth in areas requiring further analysis of uncertainty and …
Date:
October 17, 2001
Creator:
Ahlers, C.
Object Type:
Report
System:
The UNT Digital Library
Advanced Computational Model for Three-Phase Slurry Reactors Progress Report: October 2001
In the second year of the project, the Eulerian-Lagrangian formulation for analyzing three-phase slurry flows in a bubble column is further developed. The approach uses an Eulerian analysis of liquid flows in the bubble column, and makes use of the Lagrangian trajectory analysis for the bubbles and particle motions. An experimental set for studying a two-dimensional bubble column is also developed. The operation of the bubble column is being tested and diagnostic methodology for quantitative measurements is being developed. An Eulerian computational model for the flow condition in the two-dimensional bubble column is also being developed. The liquid and bubble motions are being analyzed and the results are being compared with the experimental setup. Solid-fluid mixture flows in ducts and passages at different angle of orientations were analyzed. The model predictions were compared with the experimental data and good agreement was found. Gravity chute flows of solid-liquid mixtures is also being studied. Further progress was also made in developing a thermodynamically consistent model for multiphase slurry flows with and without chemical reaction in a state of turbulent motion. The balance laws are obtained and the constitutive laws are being developed. Progress was also made in measuring concentration and velocity of …
Date:
October 1, 2001
Creator:
Ahmadi, Goodarz
Object Type:
Report
System:
The UNT Digital Library
Measurement of Recombination Parameters of Photovoltaic Materials by Resonant-Coupled Photoconductive Decay: Preprint
Presented at the 2001 NCPV Program Review Meeting: Novel contactless measurement technique that provides minority carrier lifetime, ambipolar mobility, and diffusion length.
Date:
October 1, 2001
Creator:
Ahrenkiel, R. & Johnston, S.
Object Type:
Article
System:
The UNT Digital Library
Characterizing the fabric of the urban environment: A case studyof Metropolitan Chicago, Illinois and Executive Summary
Urban fabric data are needed in order to estimate the impactof light-colored surfaces (roofs and pavements) and urban vegetation(trees, grass, shrubs) on the meteorology and air quality of a city, andto design effective implementation programs. In this report, we discussthe result of a semi-automatic Monte-Carlo statistical approach used todevelop data on surface-type distribution and city-fabric makeup(percentage of various surface-types) using aerial colororthophotography. The digital aerial photographs for metropolitan Chicagocovered a total of about 36 km2 (14 mi2). At 0.3m resolution, there wereapproximately 3.9 x 108 pixels of data. Four major land-use types wereexamined: commercial, industrial, residential, andtransportation/communication. On average, for the areas studied, atground level vegetation covers about 29 percent of the area (ranging 4 80percent); roofs cover about 25 percent (ranging 8 41 percent), and pavedsurfaces about 33 percent (ranging 12 59 percent). For the most part,trees shade streets, parking lots, grass, and side-walks. In commercialareas, paved surfaces cover 50 60 percent of the area. In residentialareas, on average, paved surfaces cover about 27percent of the area.Land-use/land-cover (LULC) data from the United States Geological Surveywas used to extrapolate these results from neighborhood scales tometropolitan Chicago. In an area of roughly 2500 km2, defining most ofmetropolitan Chicago, over 53 percent …
Date:
October 30, 2001
Creator:
Akbari, Hashem & Rose, Leanna Shea
Object Type:
Report
System:
The UNT Digital Library
Final technical report for Interagency Agreement No. DE-AI02-98ER62683: Development of a functional genomics approach to use radiation-induced changes in gene expression to monitor for low dose and low dose-rate exposures
Microarray analysis and other molecular biology techniques were used to investigate the regulation of gene expression following ionizing radiation exposure.
Date:
October 23, 2001
Creator:
Albert J. Fornace, Jr.
Object Type:
Report
System:
The UNT Digital Library
[Scarbrough Building Photograph #2]
Photograph of the Scarbrough Building, in Austin, Texas.
Date:
October 2001
Creator:
Allen, Phoebe
Object Type:
Photograph
System:
The Portal to Texas History
[Scarbrough Building Photograph #3]
Photograph of the Scarbrough Building, in Austin, Texas.
Date:
October 2001
Creator:
Allen, Phoebe
Object Type:
Photograph
System:
The Portal to Texas History
[Scarbrough Building Photograph #4]
Photograph of the Scarbrough Building, in Austin, Texas.
Date:
October 2001
Creator:
Allen, Phoebe
Object Type:
Photograph
System:
The Portal to Texas History
[Scarbrough Building Photograph #5]
Photograph of the Scarbrough Building, in Austin, Texas.
Date:
October 2001
Creator:
Allen, Phoebe
Object Type:
Photograph
System:
The Portal to Texas History
[Scarbrough Building Photograph #6]
Photograph of the Scarbrough Building, in Austin, Texas.
Date:
October 2001
Creator:
Allen, Phoebe
Object Type:
Photograph
System:
The Portal to Texas History
Dose-to-Man From SRP Waste: Sensitivity to Leaching and Rock Properties
This report summarizes results of a sensitivity analysis that predicts which features of the waste form and barrier system will have the greatest impact on dose to man.
Date:
October 15, 2001
Creator:
Allender, J.S.
Object Type:
Report
System:
The UNT Digital Library
BAC-G2 Predictions of Thermochemistry for Gas-Phase Aluminum Compounds
A self-consistent set of thermochemical data for 55 molecules in the Al-H-C-O-F-Cl system are obtained from ab initio quantum-chemistry calculations using the BAC-G2 method. Calculations were performed for both stable and radical species. Good agreement is found between the calculations and experimental heats of formation in most cases where data are available for comparison. Electronic energies, molecular geometries, moments of inertia, and vibrational frequencies are provided in the Supporting Information, as are polynomial fits of the thermodynamic data (heat of formation, entropy, and heat capacity) over the 300--3000 K temperature range.
Date:
October 2001
Creator:
Allendorf, Mark D.
Object Type:
Report
System:
The UNT Digital Library
High Temperature Surface Measurements Using Lifetime Imaging of Thermographic Phosphors: Bonding Tests
Temperature-sensitive paint (TSP) comprised of thermally sensitive phosphor can provide a viable means for noncontact thermometry in wind tunnel and other aeropropulsion applications. Described here are recent results aimed at developing a phosphor and binder system that will cover a wide temperature range, ambient to 1000 C. The phosphor/binder mixture is to be sprayed directly on the surface with an airbrush. Whereas many surfaces are candidates for various uses, the present effort concerned silicon carbide, silicon nitride and silica substrates. Initial tests show that a phosphor mixture with two water-soluble materials, designated LK and HPC and manufactured by ZYP Inc., adhered well to these substrates. This same material was earlier shown to function well on a high strength nickel alloy.
Date:
October 29, 2001
Creator:
Allison, S. W.
Object Type:
Article
System:
The UNT Digital Library
Indirect-Drive Noncryogenic Double-Shell Ignition Targets for the National Ignition Facility: Design and Analysis
The central goal of the National Ignition Facility (NIF) is demonstration of controlled thermonuclear ignition. The mainline ignition target is a low-Z, single-shell cryogenic capsule designed to have weakly nonlinear Rayleigh-Taylor growth of surface perturbations. Double-shell targets are an alternative design concept that avoids the complexity of cryogenic preparation but has greater physics uncertainties associated with performance-degrading mix. A typical double-shell design involves a high-Z inner capsule filled with DT gas and supported within a low-Z ablator shell. The largest source of uncertainty for this target is the degree of highly evolved nonlinear mix on the inner surface of the high-Z shell. High Atwood numbers and feed-through of strong outer surface perturbation growth to the inner surface promote high levels of instability. The main challenge of the double-shell target designs is controlling the resulting nonlinear mix to levels that allow ignition to occur. Design and analysis of a suite of indirect-drive NIF double-shell targets with hohlraum temperatures of 200 eV and 250 eV are presented. Analysis of these targets includes assessment of two-dimensional radiation asymmetry as well as nonlinear mix. Two-dimensional integrated hohlraum simulations indicate that the x-ray illumination can be adjusted to provide adequate symmetry control in hohlraums specially …
Date:
October 15, 2001
Creator:
Amendt, P.; Colvin, J.; Tipton, R. E.; Hinkel, D.; Edwards, M. J.; Landen, O. L. et al.
Object Type:
Article
System:
The UNT Digital Library
House and Senate Chaplains
This report discusses the two chaplains, one in the House, the other in the Senate, who are the official clergy of Congress. At the beginning of each Congress, the House chaplain is elected for a 2-year term. The Senate chaplain does not have to be reelected at the beginning of a new Congress. There have been 61 Senate chaplains and 59 House chaplains.
Date:
October 9, 2001
Creator:
Amer, Mildred
Object Type:
Report
System:
The UNT Digital Library
Southwest Retort, Volume 54, Number 2, October 2001
This publication of the Dallas-Fort Worth Section of the American Chemical Society includes information about research, prominent scientist, organizational business, and various other stories of interest to the community.
Date:
October 2001
Creator:
American Chemical Society. Dallas/Fort Worth Section.
Object Type:
Journal/Magazine/Newsletter
System:
The UNT Digital Library
Impact of the implementation of MPI point-to-point communications on the performance of two general sparse solvers
We examine the mechanics of the send and receive mechanism of MPI and in particular how we can implement message passing in a robust way so that our performance is not significantly affected by changes to the MPI system. This leads us to using the Isend/Irecv protocol which will entail sometimes significant algorithmic changes. We discuss this within the context of two different algorithms for sparse Gaussian elimination that we have parallelized. One is a multifrontal solver called MUMPS, the other is a supernodal solver called SuperLU. Both algorithms are difficult to parallelize on distributed memory machines. Our initial strategies were based on simple MPI point-to-point communication primitives. With such approaches, the parallel performance of both codes are very sensitive to the MPI implementation, the way MPI internal buffers are used in particular. We then modified our codes to use more sophisticated nonblocking versions of MPI communication. This significantly improved the performance robustness (independent of the MPI buffering mechanism) and scalability, but at the cost of increased code complexity.
Date:
October 10, 2001
Creator:
Amestoy, Patrick R.; Duff, Iain S.; L'Excellent, Jean-Yves & Li, Xiaoye S.
Object Type:
Article
System:
The UNT Digital Library
Ion flux from vacuum arc cathode spots in the absence and presence of a magnetic field
Because plasma production at vacuum cathode spots is approximately proportional to the arc current, arc current modulation can be used to generate ion current modulation that can be detected far from the spot using a negatively biased ion collector. The drift time to the ion detector can used to determine kinetic ion energies. A very wide range of cathode materials have been used. It has been found that the kinetic ion energy is higher at the beginning of each discharge and approximately constant after 150 {micro}s. The kinetic energy is correlated with the arc voltage and the cohesive energy of the cathode material. The ion erosion rate has in inverse relation to the cohesive energy, enhancing the effect that the power input per plasma particle correlates with the cohesive energy of the cathode material. The influence of three magnetic field configurations on the kinetic energy has been investigated. Generally, a magnetic field increases the plasma impedance, arc burning voltage, and kinetic ion energy. However, if the plasma is produced in a region of low field strength and streaming into a region of higher field strength, the velocity may decrease due to the mirror effect. A magnetic field can increase the …
Date:
October 2, 2001
Creator:
Anders, Andre & Yushkov, George Yu.
Object Type:
Article
System:
The UNT Digital Library
Effect of secondary structure on the interactions of peptide T4 LYS (11-36) in mixtures of aqueous sodium chloride and 2,2,2,-Trifluoroethanol
The potential of mean force for protein-protein interactions is key to the development of a statistical-mechanical model for salt-induced protein precipitation and crystallization, and for understanding certain disease states, including cataract formation and {beta}-amyloid pathology in Alzheimer's disease. Fluorescence anisotropy provides a method for quantitative characterization of intermolecular interactions due to reversible association. Monomer-dimer equilibria for the peptide T4 LYS(11-36) were studied by fluorescence anisotropy. This peptide, derived from the {beta}-sheet region of the T4 lysozyme molecule, has the potential to form amyloid fibrils. 2,2,2-trifluoroethanol (TFE) induces a change in peptide secondary structure, and was used in aqueous solutions at concentrations from 0 to 50% (v/v) at 25 and 37 C to examine the role of peptide conformation on peptide-peptide interactions. The association constant for dimerization increased with rising TFE concentration and with falling temperature. The peptide-peptide potential of mean force was computed from these association constants. Circular-dichroism measurements showed that the secondary structure of the peptide plays an important role in these strong attractive interactions due to intermolecular hydrogen-bond formation and hydrophobic interactions.
Date:
October 1, 2001
Creator:
Anderson, Camille O.; Spiegelberg, Susanne; Prausnitz, John M. & Blanch, Harvey W.
Object Type:
Report
System:
The UNT Digital Library
Arbitrary Lagrangian-Eulerian Method with Local Structured Adaptive Mesh Refinement for Modeling Shock Hydrodynamics
A new method that combines staggered grid Arbitrary Lagrangian-Eulerian (ALE) techniques with structured local adaptive mesh refinement (AMR) has been developed for solution of the Euler equations. This method facilitates the solution of problems currently at and beyond the boundary of soluble problems by traditional ALE methods by focusing computational resources where they are required through dynamic adaption. Many of the core issues involved in the development of the combined ALEAMR method hinge upon the integration of AMR with a staggered grid Lagrangian integration method. The novel components of the method are mainly driven by the need to reconcile traditional AMR techniques, which are typically employed on stationary meshes with cell-centered quantities, with the staggered grids and grid motion employed by Lagrangian methods. Numerical examples are presented which demonstrate the accuracy and efficiency of the method.
Date:
October 22, 2001
Creator:
Anderson, R W; Pember, R B & Elliott, N S
Object Type:
Article
System:
The UNT Digital Library
Beryllium poisoning in the MARIA reactor.
None
Date:
October 2, 2001
Creator:
Andrzejewski, K.; Kulikowska, T.; Bretscher, M. M. & Matos, J. E.
Object Type:
Article
System:
The UNT Digital Library
SULFUR REDUCTION IN GASOLINE AND DIESEL FUELS BY EXTRACTION/ADSORPTION OF REFRACTORY DIBENZOTHIOPHENES
Using the classical coordination compound, Ru(NH{sub 3}){sub 5}(H{sub 2}O){sup 2+}, they have prepared a metal complex with a 4,6-dimenthyldibenzothiophene ligand. The compound Ru(NH{sub 3}){sub 5}(H{sub 2}O){sup 2+} also reacts with thiophene, benzothiophene and dibenzothiophene (DBT) at room temperature. They have found that Ru(NH{sub 3}){sub 5}(H{sub 2}O){sup 2+} removes over 50% of the DBT in simulated petroleum feedstocks by a biphasic extraction process. The extraction phase is readily generated by air-oxidation thereby completing a cyclic process that removes DBT from petroleum feedstocks.
Date:
October 1, 2001
Creator:
Angelici, Robert J.; McKinley, Scott G. & Alvarez, Celedonio
Object Type:
Report
System:
The UNT Digital Library