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Full-Text Articles in Physical Sciences and Mathematics

Development And Field Testing Of Pulse Introduction Membrane Extraction (Pime) For Measurement Of Ground Water Contamination, Anthony San Juan Aug 1998

Development And Field Testing Of Pulse Introduction Membrane Extraction (Pime) For Measurement Of Ground Water Contamination, Anthony San Juan

Theses

VOCs are a class of aromatic and aliphatic compounds with a variety of functional groups, and are in general detrimental to human health even at trace levels. Conventional analysis of VOCs in groundwater usually involves sampling at site followed by laboratory analysis. This results in long turn around times, high cost and also errors associated with sample preservation during transportation and storage. In order to address these problems, a field portable instrument referred to as Pulse Introduction Membrane Extraction (PIME) has been developed for monitoring trace level halogenated organic contaminants in ground water. A membrane extraction approach has been used, …


In Vitro Cytotoxicity Study Of Glutaraldehyde And No-React Treated Bioprosthetic Heart Valves And The Aortic Wall, Roger Ongosi May 1998

In Vitro Cytotoxicity Study Of Glutaraldehyde And No-React Treated Bioprosthetic Heart Valves And The Aortic Wall, Roger Ongosi

Theses

Valvular failure due to calcification and leaflet disruption of artificial bioprostheses is still a major concern in valve replacement surgery. Previous studies have shown that Glutaraldehyde, a chemical used in the treatment of artificial valves promotes calcification. In this investigation glutaraldehyde and No-React® treated tissue samples of pericardium, cusp and the aortic wall were tested for cytocompatibility using live mouse fibroblast cultures. The samples were cut into 3 X 3 mm2 washed in phosphate buffered saline solution, transferred into cell culture flask containing cells that had been cultured for 24 hours and incubated at 37 "C in 5 % CO2. …


Catalyctic Reduction Of Nitric Oxide By Carbon Monoxide And Copper Loaded Granular Activated Carbon In The Presence Of Oxygen, Kaiwen Ma May 1998

Catalyctic Reduction Of Nitric Oxide By Carbon Monoxide And Copper Loaded Granular Activated Carbon In The Presence Of Oxygen, Kaiwen Ma

Theses

The reduction reaction of nitric oxide (NO) by carbon monoxide (CO), and granular activated carbon (GAC) in the presence and absence of oxygen was studied in a fixed bed catalytic reactor. The conversion of NO as a function of reaction temperature was evaluated for various reductant to NO ratios and space velocities. The results show that oxygen enhanced the NO+CO reaction over copper (Cu) ion exchanged ZSM-5. About 60% NO conversion to nitrogen (N2) was obtained at 400°C and 2,000 v/v/hr. This result is consistent with the hypothesis that CO is an intermediate in the soot-NO reaction. The …


Thermodynamic Properties Of Chlorocarbons And Kinetic Analysis For A- And B -Addition Of Oh+C2h3cl, Li Zhu Jan 1998

Thermodynamic Properties Of Chlorocarbons And Kinetic Analysis For A- And B -Addition Of Oh+C2h3cl, Li Zhu

Theses

Thermodynamic properties, ΔHf°298, S°298 and Cp(T) 300≤T/K≤1500, for C1, C2 chlorocarbons are calculated by AM1 and PM3 in MOPAC6, then compared with the literature data. AM1- and PM3-derived S°298 and Cp(T) (300≤T/K≤1500) are found to be consistent with the literature (Rd ≤ ± 5%). ΔHf°298 of CH2Cl2, CH2ClCH2Cl, CH2ClCHCl2, CHCl2CHCl2, and C2Cl4 and C2Cl2 calculated by PM3 as well as ΔHf°298 of CCl4, C2HCl3, …