The Hexagon, Volume 93, Number 3, Fall 2002

The Hexagon, Volume 93, Number 3, Fall 2002

Date: Autumn 2002
Creator: Alpha Chi Sigma
Description: Quarterly publication of the Alpha Chi Sigma chemistry fraternity containing articles related to chemistry research and the activities of the organization, including local chapters and groups.
Contributing Partner: UNT Libraries
Rediscovery of the Elements: Strontium

Rediscovery of the Elements: Strontium

Date: Autumn 2002
Creator: Marshall, James L., 1940- & Marshall, Virginia R.
Description: Article describing the history of the element strontium from its discovery in Strontian, Scotland, to its early uses in English medicine. Maps with directions and photographs of pertinent locations are included.
Contributing Partner: UNT College of Arts and Sciences
Comprehensive supernate treatment: Task summary

Comprehensive supernate treatment: Task summary

Date: November 29, 1995
Creator: Egan, B.Z.; Collins, J.L.; Anderson, K.K. & Chase, C.W.
Description: Short communication.
Contributing Partner: UNT Libraries Government Documents Department
Ion sorption onto hydrous ferric oxides: Effect on major element fluid chemistry at Aspo, Sweden

Ion sorption onto hydrous ferric oxides: Effect on major element fluid chemistry at Aspo, Sweden

Date: June 1, 1996
Creator: Bruton, C.J. & Viani, B.E.
Description: The observed variability of fluid chemistry at the Aespoe Hard Rock Laboratory is not fully described by conservative fluid mixing models. Ion exchange may account for some of the observed discrepancies. It is also possible that variably charged solids such as oxyhydroxides of Fe can serve as sources and sinks of anions and cations through surface complexation. Surface complexation reactions on hydrous ferric oxides involve sorption of both cations and anions. Geochemical modeling of the surface chemistry of hydrous ferric oxides (HFOs) in equilibrium with shallow HBH02 and deep KA0483A waters shows that HFOs can serve as significant, pH-sensitive sources and sinks for cations and anions. Carbonate sorption is favored especially at below-neutral pH. A greater mass of carbonate is sorbed onto HFO surfaces than is contained in the fluid when 10 g goethite, used as a proxy for HFOs, is in contact with 1 kg H{sub 2}O. The masses of sorbent required to significantly impact fluid chemistry through sorption/desorption reactions seem to be reasonable when compared to the occurrences of HFOs at Aespoe. Thus, it is possible that small changes in fluid chemistry can cause significant releases of cations or anions from HFOs into the fluid phase or, alternately, ...
Contributing Partner: UNT Libraries Government Documents Department
Review and evaluation of extractants for strontium removal using magnetically assisted chemical separation

Review and evaluation of extractants for strontium removal using magnetically assisted chemical separation

Date: November 1, 1995
Creator: Bauer, C.B.; Rogers, R.D.; Nunez, L.; Ziemer, M.D.; Pleune, T.T. & Vandegrift, G.F.
Description: A literature review on extractants for strontium removal was initially performed at Northern Illinois University to assess their potential in magnetically assisted chemical separation. A series of potential strontium extractants was systematically evaluated there using radioanalytical methods. Initial experiments were designed to test the uptake of strontium from nitric acid using several samples of magnetic extractant particles that were coated with various crown ether ligands. High partition coefficient (K{sub d}) values for stimulant tank waste were obtained. Further studies demonstrated that the large partitioning was due to uncoated particles.
Contributing Partner: UNT Libraries Government Documents Department
Enhancement of methane conversion using electric fields. Quarterly report, July--September 1995

Enhancement of methane conversion using electric fields. Quarterly report, July--September 1995

Date: November 1, 1995
Creator: Mallinson, R.G. & Lobban, L.L.
Description: The goal of this project is the development of novel, economical, processes for the conversion of natural gas to more valuable projects such as methanol, ethylene and other organic oxygenates or higher hydrocarbons. The methodologies of the project are to investigate and develop low temperature electric discharges and electric field-enhanced catalysis for carrying out these conversions. In the case of low temperature discharges, the conversion is carried out at ambient temperature which in effect trades high temperature thermal energy for electric energy as the driving force for conversion. The low operating temperatures relax the thermodynamic constraints on the product distribution found at high temperature and also removes the requirements of large thermal masses required for current technologies. With the electric field-enhanced conversion, the operating temperatures are expected to be below those currently required for such processes as oxidative coupling, thereby allowing for a higher degree of catalytic selectivity while maintaining high activity.
Contributing Partner: UNT Libraries Government Documents Department
Geochemical and Pb, Sr, and O isotopic study of the Tiva Canyon Tuff and Topopah Spring Tuff, Yucca Mountain, Nye County, Nevada

Geochemical and Pb, Sr, and O isotopic study of the Tiva Canyon Tuff and Topopah Spring Tuff, Yucca Mountain, Nye County, Nevada

Date: December 31, 1995
Creator: Neymark, L.A.; Marshall, B.D.; Kwak, L.M.; Futa, Kiyoto & Mahan, S.A.
Description: Yucca Mountain is currently being studied as a potential site for an underground repository for high-level radioactive waste. One aspect of the site characterization studies is an evaluation o the resource potential at Yucca Mountain. Geochemical and isotopic signatures of past alteration of the welded tuffs that underlie Yucca Mountain provide a means of assessing the probability of hydrothermal ore deposits being present within Yucca Mountain. In this preliminary report, geochemical and isotopic measurements of altered Tiva Canyon Tuff and Topopah Spring Tuff collected from fault zones exposed on the east flank of Yucca Mountain and from one drill core are compared to their unaltered equivalents sampled both in outcrop and drill core. The geochemistry and isotopic compositions of unaltered Tiva Canyon Tuff and Topopah Spring Tuff (high-silica rhyolite portions) are fairly uniform; these data provide a good baseline for comparisons with the altered samples. Geochemical analyses indicate that the brecciated tuffs are characterized by addition of calcium carbonate and opaline silica; this resulted in additions of calcium and strontium,increases in oxygen-18 content, and some redistribution of trace elements. After leaching the samples to remove authigenic carbonate, no differences in strontium or lead isotope compositions between altered and unaltered sections ...
Contributing Partner: UNT Libraries Government Documents Department
Centrifugal contractors for laboratory-scale solvent extraction tests

Centrifugal contractors for laboratory-scale solvent extraction tests

Date: December 31, 1995
Creator: Leonard, R.A.; Chamberlain, D.B. & Conner, C.
Description: A 2-cm contactor (minicontactor) was developed and used at Argonne National Laboratory for laboratory-scale testing of solvent extraction flowsheets. This new contactor requires only 1 L of simulated waste feed, which is significantly less than the 10 L required for the 4-cm unit that had previously been used. In addition, the volume requirements for the other aqueous and organic feeds are reduced correspondingly. This paper (1) discusses the design of the minicontactor, (2) describes results from having applied the minicontactor to testing various solvent extraction flowsheets, and (3) compares the minicontactor with the 4-cm contactor as a device for testing solvent extraction flowsheets on a laboratory scale.
Contributing Partner: UNT Libraries Government Documents Department
Separation of strontium from fecal matter

Separation of strontium from fecal matter

Date: December 31, 1994
Creator: Kester, D.K.
Description: The present invention relates to a method of separating strontium, and, more particularly, to a method of separating strontium from a sample of biomass potentially contaminated with various radionuclides. Radioactive strontium is a radionuclide which represents a hazard to man because of its long half-life and, if ingested, its tendency to be retained in the human body. In the event that radionuclides such as strontium or various actinides are ingested, it is desirable to monitor the discharge or release of these radionuclides from the human body through analysis of fecal matter. In laboratories and other facilities where potential for radionuclide contamination exists, fecal analysis for strontium is routinely conducted for individuals who are terminating from their position or are suspected of having been contaminated with radionuclides. Methods for separating and analyzing radioactive actinides from a biomass sample are well known and have been extensively developed for the US Department of Energy. These methods, described in the Department`s internal procedure, USDOE, RESL/ID, A-16, 1981, as well as in US Patent 5,190,881, involve the use of an iron phosphate precipitation step to separate actinides from a solution, or supernate. However, there are no established procedures for the separation of strontium from a ...
Contributing Partner: UNT Libraries Government Documents Department
H-Area Hazardous Waste Management Facility groundwater monitoring report, Third and fourth quarters 1995: Volume 1

H-Area Hazardous Waste Management Facility groundwater monitoring report, Third and fourth quarters 1995: Volume 1

Date: March 1, 1996
Creator: unknown
Description: Groundwater at the H-Area Hazardous Waste Management Facility (HWMF) is monitored in compliance with applicable regulations. Monitoring results are compared to the South Carolina Department of Health and Environmental control (SCDHEC) Groundwater Protection Standard (GWPS). Historically as well as currently, nitrate-nitrite as nitrogen, nonvolatile beta, and tritium have been among the primary constituents to exceed standards. Other radionuclides and hazardous constituents also exceeded the GWPS in the second half of 1995. Elevated constituents were found primarily in the water table (Aquifer Zone IIB{sub 2}), however, constitutents exceeding standards also occurred in several different aquifer zones monitoring wells. Water-level maps indicate that the groundwater flow rates and directions at the H-Area HWMF have remained relatively constant since the basins ceased to be active in 1988.
Contributing Partner: UNT Libraries Government Documents Department
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