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NCAW feed chemistry: Effect of starting chemistry on melter offgas and iron redox

Description: The Pacific Northwest Laboratory (PNL) Vitrification Technology Development (PVTD) program has been established to develop technology to support immobilization of selected Hanford wastes. The effort of the PVTD program is directed by the U.S. Department of Energy (DOE). This report is part of the effort and focuses on the effect of starting waste chemistry on the vitrification process. The objective of the investigation was the evaluation of the effect of starting chemistry on the cold cap beha… more
Date: March 1, 1995
Creator: Smith, P.A.; Vienna, J.D. & Merz, M.D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Strategic thinking in chemistry and materials

Description: Science and technology challenges facing the Chemistry and Materials program relate to the fundamental problem of addressing the critical needs to improve our understanding of how nuclear weapons function and age, while experiencing increased pressures to compensate for a decreasing technology base. Chemistry and materials expertise is an enabling capability embedded within every aspect of nuclear weapons design, testing, production, surveillance and dismantlement. Requirements to capture an en… more
Date: November 1995
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Method performance for radioanalytical chemistry

Description: This document provides method qualification data for radioanalytical procedures as required by WHC-SD-CP-QAPP-016. A short description of the Methodology, the original source(s) of the methodology, a MDC example, and precision and accuracy from historic data.
Date: September 1, 1995
Creator: Catlow, S. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Studies of the chemistry of transuranium elements and technetium at the Institute of Physical Chemistry, Russian Academy of Sciences, supported by the US Department of Energy

Description: Studies at Hanford in the 1980s revealed the potential for actinides to form stable soluble complexes in alkaline media, simulating radioactive tank waste. Pu(IV) hydrous oxide and Pu(VI) solubility increased with hydroxide concentration, ionic strength, and aluminate/carbonate concentrations. Subsequent contacts between US and Russian researchers in 1993 led to a technical literature review of the chemistry of TRU and Tc in alkaline media; this review addresses oxidation states, solubility, sp… more
Date: April 1995
Creator: Peretrukhin, V. F. & Delegard, C. H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Modeling actinide chemistry with ASPEN PLUS

Description: When chemical engineers think of chemical processing, they often do not include the US government or the national laboratories as significant participants. Compared to the scale of chemical processing in the chemical process, petrochemical and pharmaceutical industries, the government contribution to chemical processing is not large. However, for the past fifty years, the US government has been, heavily involved in chemical processing of some very specialized materials, in particular, uranium a… more
Date: December 31, 1995
Creator: Grigsby, C. O.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Molten fluoride fuel salt chemistry

Description: The chemistry of molten fluorides is traced from their development as fuels in the Molten Salt Reactor Experiment with important factors in their selection being discussed. Key chemical characteristics such as solubility, redox behavior, and chemical activity are explained as they relate to the behavior of molten fluoride fuel systems. Development requirements for fitting the current state of the chemistry to modern nuclear fuel system are described. It is concluded that while much is known abo… more
Date: February 1, 1995
Creator: Toth, L.M.; Del Cul, G.D.; Dai, S. & Metcalf, D.H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Fundamental surface chemistry of GaAs OMVPE

Description: Organometallic and hydride compounds are widely used as precursors for the epitaxial growth of GaAs and other compound semiconductors. These precursors are most commonly used to perform organometallic vapor phase epitaxy (OMVPE) and also in related deposition techniques such as atomic layer epitaxy (ALE) and metalorganic molecular beam epitaxy (MOMBE). We have investigated the surface chemical properties of these precursors on GaAs(100) using a variety of surface science diagnostics. Results ha… more
Date: May 1, 1995
Creator: Creighton, J.R. & Truong, C.M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Advancing manufacturing through computational chemistry

Description: The capabilities of nanotechnology and computational chemistry are reaching a point of convergence. New computer hardware and novel computational methods have created opportunities to test proposed nanometer-scale devices, investigate molecular manufacturing and model and predict properties of new materials. Experimental methods are also beginning to provide new capabilities that make the possibility of manufacturing various devices with atomic precision tangible. In this paper, we will discuss… more
Date: December 31, 1995
Creator: Noid, D. W.; Sumpter, B. G. & Tuzun, R. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

On the numerical treatment of problems in atmospheric chemistry

Description: Atmospheric chemical-radiative-transport (CRT) models are vital in performing research on atmospheric chemical change. Even with the enormous computing capability delivered by massively parallel systems, extended three dimensional CRT simulations are still not computationally feasible. The major obstacle in a CRT model is the nonlinear ODE system describing the chemical kinetics in the model. These ODE systems are usually very stiff and account for anywhere from 75% to 90% of the CPU time requi… more
Date: September 1, 1995
Creator: Aro, C.J.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
open access

Eleventh international symposium on radiopharmaceutical chemistry

Description: This document contains abstracts of papers which were presented at the Eleventh International Symposium on Radiopharmaceutical Chemistry. Sessions included: radiopharmaceuticals for the dopaminergic system, strategies for the production and use of labelled reactive small molecules, radiopharmaceuticals for measuring metabolism, radiopharmaceuticals for the serotonin and sigma receptor systems, labelled probes for molecular biology applications, radiopharmaceuticals for receptor systems, radioph… more
Date: December 31, 1995
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Opportunities and challenges of high-performance computing in chemistry

Description: The field of high-performance computing is developing at an extremely rapid pace. Massively parallel computers offering orders of magnitude increase in performance are under development by all the major computer vendors. Many sites now have production facilities that include massively parallel hardware. Molecular modeling methodologies (both quantum and classical) are also advancing at a brisk pace. The transition of molecular modeling software to a massively parallel computing environment offe… more
Date: June 1, 1995
Creator: Guest, M. F.; Kendall, R. A. & Nichols, J. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Integrated modeling and characterization of local crack chemistry

Description: The MULTEQ computer program has become an industry wide tool which can be used to calculate the chemical composition in a flow occluded region as the solution within concentrates due to a local boiling process. These results can be used to assess corrosion concerns in plant equipment such as steam generators. Corrosion modeling attempts to quantify corrosion assessments by accounting for the mass transport processes involved in the corrosion mechanism. MULTEQ has played an ever increasing role … more
Date: December 31, 1995
Creator: Savchik, J.A. & Burke, M.S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Plasma chemistry dependent ECR etching of GaN

Description: Electron cyclotron resonance (ECR) etching of GaN in Cl{sub 2}/H{sub 2}/Ar, C1{sub 2}/SF{sub 6}/Ar, BCl{sub 3}/H{sub 2}/Ar and BCl{sub 3}/SF{sub 6}/Ar plasmas is reported as a function of percent H{sub 2} and SF{sub 6}. GaN etch rates were found to be 2 to 3 times greater in Cl{sub 2}/H{sub 2}/Ar discharges than in BCl{sub 3}/H{sub 2}/Ar discharges independent of the H{sub 2} concentration. In both discharges, the etch rates decreased as the H{sub 2} concentration increased above 10%. When SF{s… more
Date: December 31, 1995
Creator: Shul, R.J.; Ashby, C.I.H. & Rieger, D.J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Mathematical challenges from theoretical/computational chemistry

Description: The committee believes that this report has relevance and potentially valuable suggestions for a wide range of readers. Target audiences include: graduate departments in the mathematical and chemical sciences; federal and private agencies that fund research in the mathematical and chemical sciences; selected industrial and government research and development laboratories; developers of software and hardware for computational chemistry; and selected individual researchers. Chapter 2 of this repo… more
Date: December 31, 1995
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Dilution physics modeling: Dissolution/precipitation chemistry

Description: This report documents progress made to date on integrating dilution/precipitation chemistry and new physical models into the TEMPEST thermal-hydraulics computer code. Implementation of dissolution/precipitation chemistry models is necessary for predicting nonhomogeneous, time-dependent, physical/chemical behavior of tank wastes with and without a variety of possible engineered remediation and mitigation activities. Such behavior includes chemical reactions, gas retention, solids resuspension, s… more
Date: September 1, 1995
Creator: Onishi, Y.; Reid, H.C. & Trent, D.S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Calcination/dissolution chemistry development Fiscal year 1995

Description: The task {open_quotes}IPC Liaison and Chemistry of Thermal Reconstitution{close_quotes} is a $300,000 program that was conducted in Fiscal Year (FY) 1995 with U.S. Department of Energy (DOE) Office of Research and Development (EM-53) Efficient Separations and Processing Crosscutting Program supported under technical task plan (TTP) RL4-3-20-04. The principal investigator was Cal Delegard of the Westinghouse Hanford Company (WHC). The task encompassed the following two subtasks related to the ch… more
Date: September 1, 1995
Creator: Delegard, C.H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Multiscalar measurements of turbulence-chemistry interactions in nonpremixed flames

Description: Selected results from experiments conducted over the past several years involving simultaneous multiscalar point measurements in turbulent nonpremixed flames are reviewed in this paper. In these experiments, spontaneous Raman scattering and Rayleigh scattering measurements of the major species and temperature were combined with laser-induced fluorescence measurements of minor species. The most important feature of these experiments is that they provide detailed data on the instantaneous relatio… more
Date: December 1, 1995
Creator: Barlow, R.S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Electron induced surface chemistry at the Cs/sapphire interface

Description: Electron induced etching of sapphire in the presence of Cs has been studied using a variety of surface analytical techniques. We find that this process occurs on both the (0001) and (1102) orientations of sapphire. Monolayer amounts of Al and sub-oxides of Al are thermally desorbed from the surface at temperatures as low as 1000 K when the surface is irradiated with electrons in the presence of Cs. Etching is highly dependent on Cs coverage with the (0001) and (1102) surfaces requiring 2.0 {tim… more
Date: November 1, 1995
Creator: Zavadil, K.R. & Ing, J.L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Chemistry, mineralogy, and artifical weathering of PFBC by-products

Description: Chemical and mineralogical analyses were performed on spent bed residues and cyclone ashes acquired from the TIDD pressurized fluidized bed combustion (PFBC) demonstration plant operated by American Electric Power in Brilliant, OH. The cyclone ashes were composed of fly ash, dolomite, anhydrite, periclase, and calcite in decreasing order of abundance. By comparison, bed residues contained less dolomite and fly ash but more anhydrite, calcite and periclase. All samples were highly alkaline with … more
Date: November 1, 1995
Creator: Fowler, R.K.; Soto, U.I. & Bigham, J.M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Parallel processing of atmospheric chemistry calculations: Preliminary considerations

Description: Global climate calculations are already saturating the class modern vector supercomputers with only a few central processing units. Increased resolution and inclusion of routines to deal with biogeochemical portions of the terrestrial climate system will soon demand massively parallel approaches. The atmospheric photochemistry ensemble is intimately linked to climate through the trace greenhouse gases ozone and methane and modules for representing it are being attached to global three dimension… more
Date: January 1, 1995
Creator: Elliott, S. & Jones, P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Trivalent metallocene chemistry of some uranium, titanium, and zirconium complexes

Description: Dicyclopentadienyluranium halide dimers have been prepared and their solution behavior examined. These molecules exist as dimers in solution, and the halide ligands undergo rapid site exchange on the NMR timescale above 50 C. Analogous dicyclopentadienyluranium hydroxide dimers have also been prepared; they oxidatively eliminate hydrogen to give the corresponding oxide dimers. Mechanism of this reaction is consistent with {alpha}migration of one of the hydroxide hydrogen atoms to a uranium cent… more
Date: May 1, 1995
Creator: Lukens, W. W., Jr.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
open access

Autoignition chemistry of the hexane isomers: An experimental and kinetic modeling study

Description: Autoignition of the five distinct isomers of hexane is studied experimentally under motored engine conditions and computationally using a detailed chemical kinetic reaction mechanism. Computed and experimental results are compared and used to help understand the chemical factors leading to engine knock in spark-ignited engines and the molecular structure factors contributing to octane rating for hydrocarbon fuels. The kinetic model reproduces observed variations in critical compression ratio wi… more
Date: June 1, 1995
Creator: Curran, H.J.; Gaffuri, P.; Pitz, W.J.; Westbrook, C.K. & Leppard, W.R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Mid-year report: IPC liaison and chemistry of thermal reconstitution

Description: A program of investigation into the chemistry of alkaline Hanford Site tank waste is being conducted. The investigations have two main subtasks: liaison with the Institute of Physical Chemistry of the Russian Academy of Sciences and further laboratory testing of the chemistry of thermal reconstitution of Hanford Site tank waste. Progress to date includes: (1) a technical dialogue has been established with the Institute scientists; (2) editing of a technical literature review on the chemistry of… more
Date: May 1, 1995
Creator: Delegard, C.H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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