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[Chemistry]

Description: Photograph of two student mixing chemicals in a chemistry class. The male student is pouring liquid from a graduated cylinder into a round bottom flask, while the female student is using a pipette to pour liquid into a bottle. They are surrounded by chemistry lab material and are wearing protective aprons.
Date: unknown
Partner: UNT Libraries Special Collections

Cluster Chemistry

Description: Metal cluster chemistry is one of the most rapidly developing areas of inorganic and organometallic chemistry. Prior to 1960 only a few metal clusters were well characterized. However, shortly after the early development of boron cluster chemistry, the field of metal cluster chemistry began to grow at a very rapid rate and a structural and a qualitative theoretical understanding of clusters came quickly. Analyzed here is the chemistry and the general significance of clusters with particular emphasis on the cluster research within my group. The importance of coordinately unsaturated, very reactive metal clusters is the major subject of discussion.
Date: May 1, 1980
Creator: Muetterties, Earl L.
Partner: UNT Libraries Government Documents Department

Technetium chemistry

Description: Technetium chemistry is a young and developing field. Despite the limited knowledge of its chemistry, technetium is the workhorse for nuclear medicine. Technetium is also a significant environmental concern because it is formed as a byproduct of nuclear weapons production and fission-power generators. Development of new technetium radio-pharmaceuticals and effective environmental control depends strongly upon knowledge of basic technetium chemistry. The authors performed research into the basic coordination and organometallic chemistry of technetium and used this knowledge to address nuclear medicine and environmental applications. This is the final report of a three-year Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL).
Date: April 1996
Creator: Burns, C.; Bryan, J.; Cotton, F.; Ott, K.; Kubas, G.; Haefner, S. et al.
Partner: UNT Libraries Government Documents Department

PEROXYNITRITE CHEMISTRY

Description: This century old area of research has been experiencing a renaissance during the last decade, with the annual number of publications on the subject increasing from only one in 1990 to nearly 200 in the late-1990s. This renewed interest is stimulated by the discovery of biological roles of nitric oxide, distinguished by the 1998 Nobel prize, and the recognition that the conversion of nitric oxide into peroxynitrite may play major roles in human diseases associated with oxidative stress and in cellular defense against invading pathogens. Peroxynitrite (ONOO{sup {minus}})is a structural isomer of nitrate (NO{sub 3}{sup {minus}}) that contains a peroxo bond. The physiological route to ONOO{sup {minus}} is provided by the combination of nitric oxide ({center_dot}NO) with superoxide ({center_dot}O{sub 2}{sup {minus}}), an extremely rapid reaction occurring upon every encounter of these radicals (the upper dot denotes radical species). Both {center_dot}NO and {center_dot}O{sub 2}{sup {minus}} are the oxygen metabolic products simultaneously generated in a number of cell types within a human body. Compared to its precursors, peroxynitrite is a much stronger oxidant capable of oxidizing proteins, nucleic acids, and lipids.
Date: November 29, 2000
Creator: Lymar, S. V.
Partner: UNT Libraries Government Documents Department

CLOUD CHEMISTRY.

Description: Clouds present substantial concentrations of liquid-phase water, which can potentially serve as a medium for dissolution and reaction of atmospheric gases. The important precursors of acid deposition, SO{sub 2} and nitrogen oxides NO and NO{sub 2} are only sparingly soluble in clouds without further oxidation to sulfuric and nitric acids. In the case of SO{sub 2} aqueous-phase reaction with hydrogen peroxide, and to lesser extent ozone, are identified as important processes leading to this oxidation, and methods have been described by which to evaluate the rates of these reactions. The limited solubility of the nitrogen oxides precludes significant aqueous-phase reaction of these species, but gas-phase reactions in clouds can be important especially at night.
Date: March 2001
Creator: Schwartz, S. E.
Partner: UNT Libraries Government Documents Department

Argonne premium coal sample program. Annual technical progress report. Reporting period : 2/2006-2/2007.

Description: This project provides highly uniform, premium (unexposed to oxygen) coal samples to researchers investigating coal structure, properties and behavior, and maintains accessible databases of published reports describing work carried out on the Argonne Premium Coal Samples. The samples are made available to DOE researchers and others. The eight carefully selected samples have been kept in as pristine a condition as possible through careful control the conditions in all stages from sample collection throughout processing and packaging. The samples are available in glass ampoules to ensure sample uniformity and maintain premium quality to ensure sample integrity.
Date: March 4, 2007
Creator: Hunt, J. E. & Chemistry
Partner: UNT Libraries Government Documents Department

Metals in Chemistry and Biology: Computational Chemistry Studies

Description: Numerous enzymatic reactions are controlled by the chemistry of metallic ions. This dissertation investigates the electronic properties of three transition metal (copper, chromium, and nickel) complexes and describes modeling studies performed on glutathione synthetase. (1) Copper nitrene complexes were computationally characterized, as these complexes have yet to be experimentally isolated. (2) Multireference calculations were carried out on a symmetric C2v chromium dimer derived from the crystal structure of the [(tBu3SiO)Cr(µ-OSitBu3)]2 complex. (3) The T-shaped geometry of a three-coordinate β-diketiminate nickel(I) complex with a CO ligand was compared and contrasted with isoelectronic and isosteric copper(II) complexes. (4) Glutathione synthetase (GS), an enzyme that belongs to the ATP-grasp superfamily, catalyzes the (Mg, ATP)-dependent biosynthesis of glutathione (GSH) from γ-glutamylcysteine and glycine. The free and reactant forms of human GS (wild-type and glycine mutants) were modeled computationally by employing molecular dynamics simulations, as these currently have not been structurally characterized.
Date: May 2007
Creator: Dinescu, Adriana
Partner: UNT Libraries

Gas Chemistry in Geothermal Systems

Description: Five new gas geothermometers are introduced. They are useful for predicting subsurface temperatures in water dominated geothermal systems. The geothermometers use data on CO{sub 2}, H{sub 2}S and H{sub 2} concentrations in fumarole steam as well as CO{sub 2}/H{sub 2} and H{sub 2}S/H{sub 2} ratios. It is demonstrated that the gas composition of fumarole steam may be used with or withour drillhole data to evaluate steam condensation in the upflow zones of geothermal systems. Uncertainty exists, however, in distinguishing between the effects of steam condensation and phase separation at elevated pressures. The gas content in steam from discharging wells and the solute content of the water phase can be used to evaluate which boiling processes lead to "excess steam" in the discharge and at which temperature this "excess steam" is added to the fluid moving through the aquifer and into the well. Examples, using field data, are given to demonstrate all the mentioned applications of geothermal chemistry.
Date: December 15, 1983
Creator: Arnorsson, Stefan & Gunnlaugsson, Einar
Partner: UNT Libraries Government Documents Department

Advanced Chemistry Basins Model

Description: The DOE-funded Advanced Chemistry Basin model project is intended to develop a public domain, user-friendly basin modeling software under PC or low end workstation environment that predicts hydrocarbon generation, expulsion, migration and chemistry. The main features of the software are that it will: (1) afford users the most flexible way to choose or enter kinetic parameters for different maturity indicators; (2) afford users the most flexible way to choose or enter compositional kinetic parameters to predict hydrocarbon composition (e.g., gas/oil ratio (GOR), wax content, API gravity, etc.) at different kerogen maturities; (3) calculate the chemistry, fluxes and physical properties of all hydrocarbon phases (gas, liquid and solid) along the primary and secondary migration pathways of the basin and predict the location and intensity of phase fractionation, mixing, gas washing, etc.; and (4) predict the location and intensity of de-asphaltene processes. The project has be operative for 36 months, and is on schedule for a successful completion at the end of FY 2003.
Date: November 10, 2002
Creator: Goddard, William; Blanco, Mario; Cathles, Lawrence; Manhardt, Paul; Meulbroek, Peter & Tang, Yongchun
Partner: UNT Libraries Government Documents Department

Modeling the Mechano-Chemistry of NTPases

Description: This project is to develop theoretical framework for protein motors based on experimental data. Protein motors use chemical and electrochemical energies to perform mechanical work. Protein motors are machines of life. They are essential for many biological processes, including cell division, DNA transcription, replication, etc. Understanding the working mechanisms of protein motors has both scientific and medical/clinical significances, including revealing the physiological origins of certain diseases, designing of drugs against pathogens. Experiments with new techniques, especially recent advances in single molecule force measurements, have accumulated a large amount of experimental data that requires systematic theoretical analysis. We worked out a theoretical analysis on protein fluctuations to explain the recent single molecule experiment on dynamic disorders, proposed a new mechanism to explain mechanical signal propagation through the allosteric effect, a fundamental property of proteins, and examined the dynamic disorder effects on protein interaction networks. We also examined various theoretical formulations describing mechanical stress propagation in proteins, and derived mathematical formula for various approximate methods solving the mathematical equations.
Date: February 21, 2007
Creator: Xing, J
Partner: UNT Libraries Government Documents Department

[Students in chemistry library]

Description: Photograph of students and faculty in the chemistry library. Two students, one male and one female, are sitting at a table reading. The male student is reading "Chemie." Another student is browsing the card catalog while a female student behind him is looking through a flip chart. The chemistry professor is standing on a stool pulling a book from the shelf.
Date: 19uu
Partner: UNT Libraries Special Collections

Technetium Chemistry in HLW

Description: Tc contamination is found within the DOE complex at those sites whose mission involved extraction of plutonium from irradiated uranium fuel or isotopic enrichment of uranium. At the Hanford Site, chemical separations and extraction processes generated large amounts of high level and transuranic wastes that are currently stored in underground tanks. The waste from these extraction processes is currently stored in underground High Level Waste (HLW) tanks. However, the chemistry of the HLW in any given tank is greatly complicated by repeated efforts to reduce volume and recover isotopes. These processes ultimately resulted in mixing of waste streams from different processes. As a result, the chemistry and the fate of Tc in HLW tanks are not well understood. This lack of understanding has been made evident in the failed efforts to leach Tc from sludge and to remove Tc from supernatants prior to immobilization. Although recent interest in Tc chemistry has shifted from pretreatment chemistry to waste residuals, both needs are served by a fundamental understanding of Tc chemistry.
Date: June 6, 2005
Creator: Hess, Nancy J.; Felmy, Andrew R.; Rosso, Kevin M. & Yuanxian, Xia
Partner: UNT Libraries Government Documents Department

IN-PACKAGE CHEMISTRY ABSTRACTION

Description: This report was developed in accordance with the requirements in ''Technical Work Plan for Postclosure Waste Form Modeling'' (BSC 2005 [DIRS 173246]). The purpose of the in-package chemistry model is to predict the bulk chemistry inside of a breached waste package and to provide simplified expressions of that chemistry as a function of time after breach to Total Systems Performance Assessment for the License Application (TSPA-LA). The scope of this report is to describe the development and validation of the in-package chemistry model. The in-package model is a combination of two models, a batch reactor model, which uses the EQ3/6 geochemistry-modeling tool, and a surface complexation model, which is applied to the results of the batch reactor model. The batch reactor model considers chemical interactions of water with the waste package materials, and the waste form for commercial spent nuclear fuel (CSNF) waste packages and codisposed (CDSP) waste packages containing high-level waste glass (HLWG) and DOE spent fuel. The surface complexation model includes the impact of fluid-surface interactions (i.e., surface complexation) on the resulting fluid composition. The model examines two types of water influx: (1) the condensation of water vapor diffusing into the waste package, and (2) seepage water entering the waste package as a liquid from the drift. (1) Vapor-Influx Case: The condensation of vapor onto the waste package internals is simulated as pure H{sub 2}O and enters at a rate determined by the water vapor pressure for representative temperature and relative humidity conditions. (2) Liquid-Influx Case: The water entering a waste package from the drift is simulated as typical groundwater and enters at a rate determined by the amount of seepage available to flow through openings in a breached waste package.
Date: July 14, 2005
Creator: Thomas, E.
Partner: UNT Libraries Government Documents Department