1,278 Matching Results

Search Results

Advanced search parameters have been applied.

Optimum Conditions for the "Hot Zone" Volatilization of TCl₄

Description: Abstract: "The data reported herein furnish a qualitative comparison of the rapidity of vaporization of TCl4 at various "hot zone" temperatures as well as a measure of the chlorine evolution attributed to its thermal decomposition. The presence of impurities in the TCl4 detracts from the significance of the reported chlorine evolution. The temperature recommended for rapid volatilization is 750 C at which TCl4 underwent thermal decomposition amounting to no more than 0.2% by weight."
Date: February 19, 1946
Creator: Crompton, C. E.; Calkins, V. P. & Larson, C. E.
Partner: UNT Libraries Government Documents Department

The Preparation of TCl₄ With Hexachloropropylene

Description: Report discussing various reaction methods for preparing TCl₄ with hexachloropropylene, as well as various methods for drying the TCl₄ after the reaction. Experimental methods are described in detail, and experimental results are presented.
Date: July 27, 1945
Creator: Pitt, B. M.; Curran, W. F.; Schmitt, J. M.; Wagner, E. L. & Miller, A. J.
Partner: UNT Libraries Government Documents Department

Synthesis and characterization of 2-chloro-3-benzylthiopyrrolo[1,2-a]- benzimidazol-1-one and 2,3-di(benzylthio)pyrrolo[1,2-a]benzimidazol-1-one.

Description: The reaction between o-phenylenediamine and 2,3-dichloromaleic anhydride has been probed and found to give 2,3-dichloropyrrolo[1,2-a]- benzimidazol-1-one as the major product. Chlorine substitution in 2,3-dichloropyrrolo[1,2-a]benzimidazol-1-one by added benzylthiol occurs in the presence of pyridine to provide the corresponding monosulfide and disulfide derivatives. The first benzylthiol ligand undergoes reaction at the C-3 position of the five-membered pyrrolo-1-one ring, with the addition of the second benzylthiol ligand occurring at the remaining chlorine-substituted carbon. The mono- and disulfide derivatives have been isolated and characterized in solution by NMR, IR, and UV-vis spectroscopies, and the solid-state structure of 2,3-di(benzylthio)pyrrolo[1,2-a]benzimidazol-1-one has been established by X-ray crystallography.
Date: December 2003
Creator: Huang, Shih-Huang
Partner: UNT Libraries

Task 1.16 - Enhanced Mobility of Dense Nonaqueoius-Phase Liquids (DNAPLs) Using Dissolved Humic Acids

Description: Chlorinated solvent contamination is widespread across the U.S. Department of Energy (DOE) complex and other industrial facilities. Because of the physical properties of dense nonaqueous-phase liquids (DNAPLs), current treatment technologies are generally incapable of completely removing contamination from the source area. Incomplete removal means that the residual DNAPL will persist as a long-term source of groundwater contamination. When DNALPs occur in the subsurface, they resist remediation, owing to low water volubility, high viscosity and interracial tension, and microbial recalcitrance. Because of their high density and polarity, they are usually found sorbed to aquifer solids or in pools on impermeable materials. Surfactants have been used with some success to reduce interracial tension between the aqueous and organic phases and improve volubility of DNAPLs. However, surfactants are expensive and toxic and exhibit an oxygen demand. An alternative is the use of dissolved humic acids in improving DNAPL mobilization and solubilization. Humic acids, a. natural form of organic carbon, are abundant, inexpensive, and nontoxic; biodegrade slowly (low oxygen demand); and have excellent mobilization properties. The present work is to establish the feasibility of using humates for enhancing DNAPL remediation.
Date: August 1, 1997
Creator: Kurz, Marc D.
Partner: UNT Libraries Government Documents Department

Direct Conversion of the TF₆ to TCl₄

Description: The following report provides a general summary of some methods that could be used to convert hexafluoride into tetrafluoride, but is mainly devoted to the work done on the conversion of tetrafluoride to tetrachloride.
Date: September 25, 1945
Creator: Calkins, Vincent P.
Partner: UNT Libraries Government Documents Department

SCENARIOS EVALUATION TOOL FOR CHLORINATED SOLVENT MNA

Description: Over the past three decades, much progress has been made in the remediation of chlorinated solvents from the subsurface. Yet these pervasive contaminants continue to present a significant challenge to the U.S. Department of Energy (DOE), other federal agencies, and other public and private organizations. The physical and chemical properties of chlorinated solvents make it difficult to rapidly reach the low concentrations typically set as regulatory limits. These technical challenges often result in high costs and long remediation time frames. In 2003, the DOE through the Office of Environmental Management funded a science-based technical project that uses the U.S. Environmental Protection Agency's technical protocol (EPA, 1998) and directives (EPA, 1999) on Monitored Natural Attenuation (MNA) as the foundation on which to introduce supporting concepts and new scientific developments that will support remediation of chlorinated solvents based on natural attenuation processes. This project supports the direction in which many site owners want to move to complete the remediation of their site(s), that being to complete the active treatment portion of the remedial effort and transition into MNA. The overarching objective of the effort was to examine environmental remedies that are based on natural processes--remedies such as Monitored Natural Attenuation (MNA) or Enhanced Attenuation (EA). The research program did identify several specific opportunities for advances based on: (1) mass balance as the central framework for attenuation based remedies, (2) scientific advancements and achievements during the past ten years, (3) regulatory and policy development and real-world experience using MNA, and (4) exploration of various ideas for integrating attenuation remedies into a systematic set of ''combined remedies'' for contaminated sites. These opportunities are summarized herein and are addressed in more detail in referenced project documents and journal articles, as well as in the technical and regulatory documents being developed within the ITRC. Three topic ...
Date: August 16, 2006
Creator: Vangelas, K; Brian02 Looney, B; Truex, Michael J. & Newell, Charles J.
Partner: UNT Libraries Government Documents Department

Quarterly Groundwater Report for the Solid Waste Landfill July - September 2006

Description: This report provides information on groundwater monitoring at the Solid Waste Landfill during the quarterly time period July to September 2006. Conditions remain very similar to those reported in the previous quarterly report. Six background threshold values, one WAC 173-200 Groundwater Quality Criterion, and one WAC 246-290-310 Maximum Contaminant Level were exceeded. The results that exceed applicable limits are consistent with the type of waste disposed to the landfill including sewage and chlorinated hydrocarbons from either the sewage or the 1100 Area heavy equipment garage and bus shop.
Date: February 19, 2007
Creator: Lindberg, Jon W.
Partner: UNT Libraries Government Documents Department

The Reaction Specificity of Nanoparticles in Solution

Description: Iron-based metallic and oxide nanoparticles have been shown to have enhanced reactivity towards a variety of chemical species, including chlorinated hydrocarbons and reducible oxyanions, which frequently contaminate ground water at DOE and other government and industrial sites. Possibly of greater importance is the ability of these nanoparticles to select specific reaction pathways, potentially facilitating the formation of the most environmentally acceptable reaction products.
Date: June 1, 2006
Creator: Baer, Donald R.
Partner: UNT Libraries Government Documents Department

Scientific Basis for Monitored Natural Attenuation and Enhanced Passive Remediation for Chlorinated Solvents - DOE Alternative Project for Technology Acceleration Implementation Plan

Description: The overall Monitored Natural Attenuation and Enhanced Passive Remediation (MNA/EPR) Technology Alternative Project is narrowly focused, providing the scientific and policy support to facilitate implementing appropriate passive cleanup and cost effective monitoring strategies leading to responsible completion of active remediation activities at high risk DOE waste sites. MNA/EPR describe natural processes that mitigate exposure and risk and that are self-sustaining once implemented or require minimal adjustments to maintain functionality. The overall MNA/EPR project effort will be performed as a collaboration between DOE science and operations organizations at the target sites along with regulatory agencies, stakeholders, industry, and universities, as identified in the approved Alternative Project Plan. This plan describes the project initiation activities, individual roles and responsibilities, milestones, and budget for the project. A primary product of this project will be a collaboratively developed MNA/EPR protocol that will facilitate widespread use and acceptance. This technical protocol will be developed in collaboration with regulator agencies as input for regulation updates and guidance documents, as appropriate. This plan describes the project initiation activities, individual roles and responsibilities, milestones, and budget for the project.
Date: April 15, 2003
Creator: Vangelas, K.
Partner: UNT Libraries Government Documents Department

Characterization of anaerobic chloroethene-dehalogenating activity in several subsurface sediments

Description: Anaerobic microcosms of subsurface soils from four locations were used to investigate the separate effects of several electron donors on tetrachloroethylene (PCE) dechlorination activity. The substrates tested were methanol, formate, lactate, acetate, and sucrose. Various levels of sulfate-reducing, acetogenic, fermentative, and methanogenic activity were observed in all sediments. PCE dechlorination was detected in all microcosms, but the amount of dehalogenation varied by several orders of magnitude. Trichloroethylene was the primary dehalogenation product; however, small amounts of cis-1,2-dichloroethylene, 1,1-dichloroethylene, and vinyl chloride were also detected in several microcosms. Lactate-amended microcosms showed large amounts of dehalogenation. in three of the four sediments. One of the two sediments which showed positive activity with lactate also had large amounts of delialogenation with methanol. Sucrose, formate, and acetate also stimulated large amounts of delialogenation in one sediment that showed activity with lactate. These results suggest that lactate may be an appropriate substrate for screening sediments for PCE or TCE delialogenation activity, but that the microbial response is not sufficient for complete in situ bioremediation. A detailed study of the Victoria activity revealed that delialogenation rates were more similar to the Cornell culture than to rates measured for methanogens, or a methanol-enriched sediment culture. This may suggest that these sediments contain a highly efficient delialogenation activity similar to the Cornell culture. This assertion is supported further by the fact that an average of 3% of added reducing equivalents could be diverted to dehalogenation in tests which were conducted using PCE-saturated hexadecane as a constant source of PCE during incubation. Further evidence is needed to confirm this premise. The application of these results to in situ bioremediation of highly contaminated areas are discussed.
Date: November 1, 1996
Creator: Skeen, R.S.; Gao, J.; Hooker, B.S. & Quesenberry, R.D.
Partner: UNT Libraries Government Documents Department

Immobilization of degradative bacteria in polyurethane-based foams: embedding efficiency and effect on bacterial activity

Description: The immobilization of TCE-degrading bacterium Burkholderia cepacia was evaluated using hydrophilic polyurethane foam. The influence of several foam formulation parameters upon cell retention was examined. Surfactant type was a major determinant of retention, with a lecithin- based compound retaining more cells than pluronic or silicone based surfactants. Excessive amounts of surfactant led to increased washout of bacteria. Increasing the biomass concentration from 4.8% to 10.5% caused fewer cells to be washed out. Embedding at reduced temperature did not significantly affect retention, while the use of a silane binding agent gave inconsistent results. The optimal formulation retained all but 0.2% of total embedded cells during passage of 2 liters of water through columns containing 2 g of foam. All foam formulations tested reduced the culturability of embedded cells by several orders of magnitude. However, O{sub 2} and CO{sub 2} evolution rates of embedded cells were never less than 50% of unembedded cells. Nutrient amendments stimulated an increase in cell volume and ribosomal activity as indicated by hybridization studies using fluorescently labeled ribosomal probes. these results indicated that, although immobilized cells were nonculturable, they were metabolically active and thus could be used for biodegradation of toxic compounds.
Date: September 3, 1996
Creator: Wilde, E.W.; Radway, J.C.; Hazen, T.C. & Hermann, P.
Partner: UNT Libraries Government Documents Department

Determining Contaminant Distribution and Migration by Integrating Data from Multiple Cone Penetrometer-Based Tools

Description: The cone penetrometer has been used for geologic characterization at the U.S. Department of Energy-owned Savannah River Site for the past seven years.
Date: April 1, 1998
Creator: Rossabi, J.; Jarosch, T.R.; Riha, B.D.; Looney, B.B.; Jackson, D.G.; Eddy-Dilek, C.A. et al.
Partner: UNT Libraries Government Documents Department

Aqueous oxidation of trichloroethene (TCE): a kinetic and thermodynamic analysis

Description: An empirical kinetic rate law was determined for the aqueous oxidation of trichloroethene (TCE). By measuring both the rate of disappearance of TCE and the rate of appearance of carbon dioxide and chloride ion, mass balances were monitored to confirm that `mineralization` was the ultimate reaction. Dilute buffer solutions were used to fix pH and stoichiometrically sufficient amounts of dissolved oxygen were used to make the reactions zero-order in oxygen. Using standard chemical kinetic methods, two orders of magnitude were spanned in initial TCE concentration and used in the resulting double-log plot vs. initial rate (regressed using both linear and polynomial fits) to determine the rate constant and `true` reaction order (i.e., with respect to;concentration, not time). By determining rate constants over the temperature interval 343-373K, an Arrhenius activation energy was determined for the reaction. A study was made of the potential effect of buffer ligand concentration and type (phosphate, borate, acetate, carbonate, sulfate), ionic strength, specific electrolytes, and pH on the rate of TCE. The aqueous oxidation reaction rate was found to be pH dependent over the pH range pH 2 to pH 1O and strongly inhibited by high dissolved bromide concentration. The equilibrium aqueous solubilities of TCE was determined by making reversed measurements from 294-390K. Together with the kinetic rate law, the thermodynamic data are required to develop in situ thermal remedial techniques for TCE and to model the reactive transport behavior of TCE in the subsurface.
Date: February 28, 1998
Creator: Knauss, K. G., LLNL
Partner: UNT Libraries Government Documents Department

Soil Vapor Extraction of PCE/TCE Contaminated Soil

Description: The A/M Area of the Savannah River Site soil and groundwater is contaminated with tetrachloroethylene (PCE) and trichloroethylene (TCE). Contamination is the result of previous waste disposal practices, once considered state-of-the-art. Soil Vapor Extraction (SVE) units have been installed to remediate the A/M Area vadose zone. SVE is a proven in-situ method for removing volatile organics from a soil matrix with minimal site disturbance. SVE alleviates the infiltration of contaminants into the groundwater and reduces the total time required for groundwater remediation. Lessons learned and optimization of the SVE units are also discussed.
Date: August 1, 1998
Creator: Bradley, J.M. & Morgenstern, M.R.
Partner: UNT Libraries Government Documents Department

Cyclodextrin-based chemical microsensors for Volatile Organic Compounds (VOCs)

Description: This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). This project addressed the development of surface-acoustic-wave (SAW)-based chemical sensors for remote, real-time sensing in air, groundwater, and possibly soil, of chlorinated and aromatic hydrocarbons using innovative molecular self-assembly techniques. Our goal is parts per billion (ppb) sensitivity to specific aromatic and chlorinated hydrocarbons using cyclodextrin as the selective layer of a SAW-based mass sensor. We have demonstrated that SAW sensors can differentiate between compounds with similar composition, structure, and polarity. These efforts, however, can be enhanced by using sensor arrays and smart data processing systems. Secondly, ionic interactions provide a convenient way to fabricate thin films for sensor applications. The potential of these thin films for sensor applications is currently being evaluated. 3 figs.
Date: December 31, 1998
Creator: Li, DeQuan
Partner: UNT Libraries Government Documents Department

A/M Area Vadose Zone Monitoring Plan

Description: Characterization and monitoring data from implementation and the first two and one half years of vadose zone remediation operations indicate that this activity has substantially improved the performance of the A/M Area Groundwater Corrective Action Program. During this period, vadose zone remediation removed approximately 225, 000 lbs (100,000 Kg) of chlorinated solvents (CVOCs) from the subsurface. Further, vadose zone remediation system operation increased the overall CVOC removal rate of the A/M Area Groundwater Corrective Action by 300% to 500% during this period versus the groundwater pump and treat system along. Various support activities have been performed to support operation and documentation of performance of the vadose zone remediation system. These activities address performance of existing systems (contaminant distributions, zone of influence, and process monitoring data), evaluation of suspect sources, evaluation of alternative/enhancement technologies, and initial development of remediation goals. In particular, the most recent A/M vadose zone remediation support activities (described in WSRC-RP-97-109) were completed and the results provide key documentation about system performance.
Date: March 1998
Creator: Kupar, J.; Jarosch, T. R.; Jackson, D. G., Jr.; Looney, B. B.; Jerome, K. M.; Riha, B. D. et al.
Partner: UNT Libraries Government Documents Department

Characterization of polyxylylenes with solid state {sup 13}C nuclear magnetic resonance spectroscopy

Description: Polyxylylenes are thermoplastics used as encapsulants for electronic devices. Five polyxylylenes were prepared by pyrolysis of [2.2]paracyclophanes and characterized by solid state {sup 13}C NMR spectroscopy. The chemical shift data, in combination with interrupted decoupling experiments, allowed assignment of resonances to their carbon sources in the polymers. This confirmed the integrity of the xylylene building block in the polymers and is consistent with linear polymers. No crosslinking could be detected within the NMR sensitivity limits. Residual paracyclophane was detected by {sup 13}C CP MAS NMR spectroscopy in the polyxylylene samples prepared at room temperature; however discrete {sup 13}C resonances due to amorphous and crystalline phases in the polymers were not resolved.
Date: February 1, 1996
Creator: Loy, D.A.; Assink, R.A.; Jamison, G.M.; McNamara, W.F.; Schneider, D.A. & Prabakar, S.
Partner: UNT Libraries Government Documents Department