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Kinetic Studies of the Reactions of Cl and Br with Silane and Trimethylsilane

Description: The temperature dependence of the reactions of halogen atoms Cl and Br with SiH4 and (CH3)3SiH have been investigated with the flash photolysis-resonance fluorescence technique. CCI4 and CH2Br2 were used as precursors to produce Cl and Br atoms, respectively. Experiments gave {k(Cl + SiH4) (295 - 472 K)} = (1.56 +0.11) x 10-1 exp[(2.0 + 0.2) kJ mol'/RT] cm3 s4, {k(Br + SiH4)(295 - 575 K)} = (9.0 + 1.5) x 10-" exp[-(17.0 + 0.6) Id mol'/RT] cm3 s', {k(Cl + (CH3)3SiH)(295 - 468 K)} = (1.24 0.35) x 104 exp[(1.3 + 0.8) Id mol4/RT] cm3 s', and {k(Br + (CH3)3SiH)(295 - 456 K)} = (7.6 + 3.3) x 1010 exp[-(28.4 + 1.3) Id mol'/RT] cm3 s'. The results were compared with values from earlier work.
Date: May 1992
Creator: Ding, Luying
Partner: UNT Libraries

Synthesis and Characterization of a New Perhalogenated Porphyrin

Description: The first synthesis of an octahalotetraalkylporphyrin [2,3,7,8,12,13,17,18 -octabromo-5,10,15,20- tetrakis(trifluoromethyl)porphinato nickel(II)] is reported; this perhalogenated porphyrin has several novel properties including a very nonplanar ruffled structure with an unusually short Ni- N distance, an extremely red-shifted optical spectrum, and hindered rotation of the trifluoromethyl groups ({Delta}G<sub>278K</sub> =47 kJ mol<sup>-1</sup>).
Date: May 19, 1999
Creator: Jia, Songling; Medforth, Craig J.; Nelson, Nora Y.; Nurco, Daniel J.; Shelnutt, John & Smith, Kevin M.
Partner: UNT Libraries Government Documents Department


Description: Three and four center unimolecular elimination reactions of HCl have been investigated for CHF{sub 2}Cl, CHFCL{sub 2}, CH{sub 3}CCl{sub 3}, CH{sub 3}CF{sub 2}Cl and in a molecular beam experiment using infrared multiphoton absorption to energize the molecule. The translational energy distributions obtained in this work show that the average translational energy released to the fragments is around 8-12 kcal/mole, except for the three center elimination reaction from CHClCF{sub 2}, which gives a value of 1 kcal/mole. In four center eliminations, the translational energy released is less than 20% of the potential energy barrier of the back reaction. This is somewhat less than previous indications that approximately 30% of the potential energy barrier of the exit channel in four center reactions should be released into translation.
Date: April 1, 1978
Creator: Sudbo, Aa. S.; Schulz, P.A.; Shen, Y.R. & Lee, Y.T.
Partner: UNT Libraries Government Documents Department

Composition for detecting uranyl

Description: The present invention relates to an indicator composition for use in spectrophotometric detection of a substance in a solution, and a method for making the composition. Useful indicators are sensitive to the particular substance being measured, but are unaffected by the fluid and other chemical species that may be present in the fluid. Optical indicators are used to measure the uranium concentration of process solutions in facilities for extracting uranium from ores, production of nuclear fuels, and reprocessing of irradiated fuels. The composition comprises an organohalide covalently bonded to an indicator for the substance, in such a manner that the product is itself an indicator that provides increased spectral resolution for detecting the substance. The indicator is preferably arsenazo III and the organohalide is preferably cyanuric chloride. These form a composition that is ideally suited for detecting uranyl.
Date: January 1, 1994
Creator: Baylor, L.C. & Stephens, S.M.
Partner: UNT Libraries Government Documents Department

Photoredox reactions: Energy storage and halocarbon degradation

Description: This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objectives of this project were the following: (1) To characterize the structures and the structural dynamics of the singlet and triplet states of selected metal-metal bonded systems; (2) To characterize the post-excitation intramolecular electron transfer reactions of these complexes; (3) To investigate strongly adiabatic photo-oxidative addition reactions, including the addition of halocarbons to the electronically excited complexes and their hydrogen-evolving reactions; (4) To seek effective reductant systems that will function in catalytic cycles and regenerate the original, reduced dimer; and (5) To explore the chemistry of metals less expensive than iridium or platinum with regard to their potential for photochemical reactivity. The results include studies of W and Mo clusters with potential multielectron excited state redox reactivity, metal-metal bonded dimers sequestered in liquid crystal environments, d{sup 7} dimers with long-lived photocycles, and photochemically produced oxygen-fluorine systems.
Date: July 1, 1997
Creator: Woodruff, W.H.; Dyer, R.B. & Gray, H.B.
Partner: UNT Libraries Government Documents Department

Complex formation of beta-cyclodextrin in aqueous media with poly(N,N-dimethylacrylamide)containing pendent perfluorooctanesulfonamido groups. Final Report, September 15, 1998 - September 14, 1999

Description: The effect of time on the viscosity of solutions of 0.50--1.0 weight % polyacrylamide copolymers containing 2-(N-ethylperfluorooctanesulfonamido)ethyl acrylate (FOSA) comonomer units was monitored at constant shear rates varying from 0.60 to 3.0 sec{sup {minus}1}. The viscosities decreased to a plateau over a period of about thirty minutes. The copolymer solutions sheared at much higher shear rates of 24 sec{sup {minus}1} showed pronounced shear thinning but regained most of their original viscosities after standing for 20 minutes. Heating the solutions less than one hour caused an increase in the low shear viscosity whereas longer heating times decreased solution viscosities presumably due to hydrolysis of the acrylate groups. Addition of beta-cyclodextrin to solutions of the hydrophobically modified polyacrylamide resulted in sharply decreased copolymer viscosities at cyclodextrin concentrations on the order of about 10{sup {minus}3} M. The above is consistent with competitive hydrophobic association of the perfluorocarbon groups of the copolymer with the cyclodextrin disrupting the mutual association of the perfluorocarbon groups.
Date: November 1, 1999
Creator: Hogen-Esch, Dr. Thieo
Partner: UNT Libraries Government Documents Department

Metallurgical Laboratory Hazardous Waste Management Facility groundwater monitoring report. Second quarter 1995

Description: During second quarter 1995, samples from seven new AMB groundwater monitoring wells at the Metallurgical Laboratory Hazardous Waste Management Facility (Met Lab HWMF) were analyzed for a comprehensive list of constituents. Two parameters exceeded standards during the quarter. Lead and nickel appear to exceed final Primary Drinking Water Standards (PDWS) in AMB-18A. These data were suspect and a rerun of the samples showed levels below flagging criteria. This data will be monitored in 3Q95. Aluminum, iron, manganese, boron, silver and total organic halogens exceeded Flag 2 criteria in at least one well each during second quarter 1995. This data, as well, will be confirmed by 3Q95 testing. Groundwater flow directions in the M-Area Aquifer Zone were similar to previous quarters; the flow rate estimate, however, differs because of an error noted in the scales of measurements used for previous estimates. The estimate was 470 ft/year during second quarter 1995. Reliable estimates of flow directions and rates in the Upper Lost Lake Aquifer Zone could not be determined in previous quarters because data were insufficient. The first estimate from second quarter 1995 shows a 530 ft/year rate. Reliable estimates of flow directions and rates in the Lower Lost Lake Aquifer Zone and in the Middle Sand Aquifer Zone of the CBCU could not be calculated because of the low horizontal gradient and the near-linear distribution of the monitoring wells. During second quarter 1994, SRS received South Carolina Department of Health and Environmental Control approval for constructing five point-of-compliance wells and two plume definition wells near the Met Lab HWMF. This project began in July 1994 and was completed in March of this year. Analytical data from these wells are presented in this report for the first time.
Date: September 1, 1995
Creator: Chase, J.A.
Partner: UNT Libraries Government Documents Department

Coefficient of thermal expansion of fluorinert as a function of volume percent absorbed air

Description: The relationship between the coefficient of volumetric thermal expansion of liquid Fluorinert FC-86 and the volume percent of absorbed air was examined experimentally. A special test apparatus was built for this purpose. A floating liquid seal was used to isolate the Fluorinert sample from the atmosphere. This prevented gas absorption during thermal cycling yet allowed the sample to expand and contract freely during testing. It was found that the coefficient of thermal expansion is not influenced by the percentage of absorbed air.
Date: June 1, 1982
Creator: Reilly, J.M.
Partner: UNT Libraries Government Documents Department

Prediction of thermal front breakthrough due to fluid reinjection in geothermal reservoirs

Description: Chemically reactive tracers can be used to measure reservoir temperature distributions because of their extreme sensitivity to temperature. If a reactive tracer flows through a reservoir from an injection well to a production well, then early in the production history the tracer will contact mostly high temperatures and experience a high percentage of decomposition. As more energy is extracted from the reservoir, subsequent reactive tracer tests will show less decomposition. Tracers must be chosen which have reaction kinetics appropriate to the temperature patterns expected in the reservoir under consideration. If kinetics are too slow, no significant reaction occurs. If kinetics are too fast, essentially all of the tracer will react. In neither case can useful information be obtained. Seventeen chemically reactive tracers have been identified which are appropriate for geothermal reservoirs in the 70 to 275/sup 0/C range. Of the 17 tracer reactions investigated, 5 are hydrolysis of esters, 3 are hydrolysis of amines, and 9 are hydrolysis of aryl halides. A method for choice of the appropriate reactive tracer for a given reservoir is also presented. The method requires measurement of the residence time distribution (from a conservative tracer test), an estimate of reservoir temperature, and some simple geochemistry measurements and calculations. Several examples of choosing reactive tracers for existing geothermal reservoirs are given.
Date: January 1, 1987
Creator: Birdsell, S.A. & Robinson, B.A.
Partner: UNT Libraries Government Documents Department


Description: The recent interest in multiphoton dissociation (MPD) of polyatomic molecules has revealed quite a bit of confusion as to what the major dissociation channels of some molecules are, and whether the dissociation process can be described by a statistical, e.g., RRKM, theory of unimolecular reactions. In a gas cell experiment an experimenter often finds great difficulties in answering questions such as: do vibrationally excited molecules react with one another, how do reactions involving free radicals produced in the dissociation proceed, can these radicals decompose further in the presence of the laser field, and does the detection method used actually probe the primary dissociation channel. Using the molecular beam setup previously described, we have overcome most of these difficulties. We have studied MPD of a number of compounds, mainly halogenated methanes, ethanes and ethylenes, and identified their major dissociation channels. To identify an MPD product, we realize that a unique set of ratios between mass spectrometer signals of various ion fragments must first be established for a given molecular species or radical, and preferably the velocity distributions of the dissociation products should be measured and checked for consistency. In our setup, we could measure both angular and time-of-flight distributions for the fragments, and pereorm this check. The low density of molecules in the beam and the extremely low duty cycle in our experiment prevented us from observing the competing minor channels which have very small branching ratios (&lt; 0.1).
Date: November 1, 1977
Creator: Sudbo, Aa. S.; Schulz, P.A.; Grant, E.R & Lee, Y.T.
Partner: UNT Libraries Government Documents Department

Road Transportable Analytical Laboratory (RTAL) system: Volume II, Appendices A and B. Final report

Description: The Road Transportable Analytical Laboratory (RTAL) provides a portable analytical system for the analysis of soils, ground water, and surface water for the detection of hazardous materials, metals, organics, and radioactive material. This report presents the data results for an aqueous sample VOA report and an aqueous sample SVOA report.
Date: August 1, 1996
Creator: Finger, S.M.; De Avila, J.C. & Keith, V.F.
Partner: UNT Libraries Government Documents Department

Photocatalysis Using Semiconductor Nanoclusters

Description: We report on experiments using nanosize MoS{sub 2} to photo-oxidize organic pollutants in water using visible light as the energy source. We have demonstrated that we can vary the redox potentials and absorbance characteristics of these small semiconductors by adjusting their size, and our studies of the photooxidation of organic molecules have revealed that the rate of oxidation increases with increasing bandgap (i.e. more positive valence band and more negative conduction band potentials). Because these photocatalysis reactions can be performed with the nanoclusters fully dispersed and stable in solution, liquid chromatography can be used to determine both the intermediate reaction products and the state of the nanoclusters during the reaction. We have demonstrated that the MoS{sub 2} nanoclusters remain unchanged during the photooxidation process by this technique. We also report on studies of MoS{sub 2} nanoclusters deposited on TiO{sub 2} powder.
Date: January 21, 1999
Creator: Thurston, T.R. & Wilcoxon,J.P.
Partner: UNT Libraries Government Documents Department

Steam reforming of DOE complex waste simulants

Description: Sandia National Laboratories has worked with Synthetica Technologies and Manufacturing and Technology Conversion International (MTCl) to demonstrate the applicability of their commercial steam reforming technologies for treating DOE low-level mixed wastes. Previously, Synthetica successfully demonstrated destruction of a Sandia formulated lab trash simulant. During November 1994 Synthetica did not adequately process the aqueous halogenated organic liquid mixed waste simulant (MWTP-2110) formulated by the DOE Mixed Waste Integrated Program (MWIP). Testing at MTCl is ongoing and initial results appear to be favorable. Approximately 200 lbs each of the MWIP aqueous halogenated organic liquids (MWTP-2110), and absorbed aqueous and organic liquids (MWTP-3113/3114) simulants have been processed. At 1650{degree}F, destruction efficiencies of greater than 99% were obtained for tetrachloroethylene, toluene, and 1,2 dichlorobenzene. Product cases consisted primarily of H{sub 2}, C0{sub 2}, CO, and CH{sub 4} and had higher heating values of up to 355 BTU/SCF. Conclusions concerning the suitability of the MTCI process for treating DOE mixed wastes will be drawn upon the completion of testing.
Date: March 1, 1995
Creator: Miller, J.E. & Kuehne, P.B.
Partner: UNT Libraries Government Documents Department

Method for producing iron-based acid catalysts

Description: A method for preparing an acid catalyst with a long shelf-life is described. Crystalline iron oxides are doped with lattice compatible metals which are heated with halogen compounds at elevated temperatures.
Date: April 1, 1998
Creator: Farcasiu, M.; Kathrein, H.; Kaufman, P.B. & Diehl, J.R.
Partner: UNT Libraries Government Documents Department

Initial field test of High-Energy Corona process for treating a contaminated soil-offgas stream

Description: The High-Energy Corona (HEC) technology for treating process offgases has been under development at Pacific Northwest Laboratory (PNL) since 1991. The HEC process uses high-voltage electrical discharges in air to ionize the air, forming a low-temperature plasma that would be expected to destroy a wide variety of organic compounds in air. The plasma contains strong oxidants, possibly including hydroxyl radicals, hydroperoxy radicals, superoxide radicals, various excited as well as ionized forms of oxygen, high-energy electrons, and ultraviolet (UV) light. Because the high-voltage plasma is produced near ambient temperatures and pressures, yet exhibits extremely rapid destruction kinetics with relatively low power requirements, the HEC technique appears promising as a low-cost treatment technique (Virden et al. 1992). As part of the Volatile Organic Compound (VOC) Nonarid Integrated Demonstration (ID) at the DOE Savannah River Site, research activities were initiated in December 1991 to develop a prototype HEC process for a small-scale field demonstration to treat a soil-offgas stream contaminated with trichloroethylene (TCE) and perchloroethylene (PCE) at varying concentrations. Over an 18-month period, the HEC technology was developed on a fast track, through bench and pilot scales into a trailer-mounted system that was tested at the Nonarid ID. Other national laboratories, universities, and private companies have also participated at the Nonarid ID to demonstrate a number of conventional, emerging and innovative approaches for treating the same soil-offgas stream.
Date: April 1, 1995
Creator: Shah, R R; Garcia, R E; Jeffs, J T; Virden, J W & Heath, W O
Partner: UNT Libraries Government Documents Department


Description: Total organic halogen (TOX) is used as a parameter to screen groundwater samples at the Hanford Site. Trending is done for each groundwater well, and changes in TOX and other screening parameters can lead to costly changes in the monitoring protocol. The Waste Sampling and Characterization Facility (WSCF) analyzes groundwater samples for TOX using the United States Environmental Protection Agency (EPA) SW-846 method 9020B (EPA 1996a). Samples from the Soil and Groundwater Remediation Project (S&amp;GRP) are submitted to the WSCF for analysis without information regarding the source of the sample; each sample is in essence a 'blind' sample to the laboratory. Feedback from the S&amp;GRP indicated that some of the WSCF-generated TOX data from groundwater wells had a number of outlier values based on the historical trends (Anastos 2008a). Additionally, analysts at WSCF observed inconsistent TOX results among field sample replicates. Therefore, the WSCF lab performed an investigation of the TOX analysis to determine the cause of the outlier data points. Two causes were found that contributed to generating out-of-trend TOX data: (1) The presence of inorganic chloride in the groundwater samples: at inorganic chloride concentrations greater than about 10 parts per million (ppm), apparent TOX values increase with increasing chloride concentration. A parallel observation is the increase in apparent breakthrough of TOX from the first to the second activated-carbon adsorption tubes with increasing inorganic chloride concentration. (2) During the sample preparation step, excessive purging of the adsorption tubes with oxygen pressurization gas after sample loading may cause channeling in the activated-carbon bed. This channeling leads to poor removal of inorganic chloride during the subsequent wash step with aqueous potassium nitrate. The presence of this residual inorganic chloride then produces erroneously high TOX values. Changes in sample preparation were studied to more effectively remove inorganic chloride from the activated carbon ...
Date: September 30, 2008
Partner: UNT Libraries Government Documents Department

Nondestructive Test of Carbon Beds for Reactor Containment Applications. Progress Report, June 1962-December 1963

Description: A nondestructive technique was developed for evaluating carbon beds used in reactor containment applications. Freon-12 was used as a tracer to detect leak paths that would reduce the efficiency of carbon beds for removal of radioactive I/sub 2/ vapor. Leaks greater than 0.008% of the tothl flow were detected with an electron-capture-type instrument. The current method is suitable for testing dry carbon beds prior to field installation and at air velocities up to 20 ft/min. (auth)
Date: February 1, 1964
Creator: Peters, A. H. & Muhlbaier, D. R.
Partner: UNT Libraries Government Documents Department

Assigning mass values to in-house standard UF/sub 6/ cylinders

Description: A statistical experimental design called the Fast 4-1 Series is used to assign mass values to in-house standard UF/sub 6/ cylinders. This design is intended to minimize the number of weighings of large cylinders yet provide acceptable estimates of mass values and their precision. 5 refs.
Date: January 1, 1987
Creator: Goldman, A.; McGuire, D. & Croarkin, C.
Partner: UNT Libraries Government Documents Department

Development and testing of a rotary solar engine. Final report

Description: A rotary solar engine has been constructed and tested. By sealing Freon (having the environmentally safe composition rather than the conventionally used harmful composition) in its bellows instead of air, sufficiently consistent operation can be achieved to serve the purely mechanical rotary light-load or no-load markets. Although its power efficiency is not sufficient to make it competitive as a prime power generator, even for power outputs as low as a few ounce inches per minute, it simplicity and reliability make it an attractive self-powered source of mechanical control power for critical slow speed actuators. Its simplicity and low cost make it particularly attractive for the small (less than 10 in/sup 3/) display markets. Other markets may now be identified, now that its strength/limitations are known.
Date: unknown
Creator: Kanaly, D.B.
Partner: UNT Libraries Government Documents Department