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Full-Text Articles in Physical Sciences and Mathematics
Aerobic Denitrification Of Pseudomonas Aeruginosa Monitored By Online Nad(P)H Fluorescence, Fan Chen, Qing Xia, Lu-Kwang Ju
Aerobic Denitrification Of Pseudomonas Aeruginosa Monitored By Online Nad(P)H Fluorescence, Fan Chen, Qing Xia, Lu-Kwang Ju
Chemical, Biomolecular, and Corrosion Engineering Faculty Research
Continuous cultures of Pseudomonas aeruginosa (ATCC 9027) maintained at different dissolved oxygen concentrations (DO) were studied for the effects of DO on various culture properties, especially aerobic respiration and denitrification. The DO was varied from 0 mg/liter (completely anoxic conditions) to 1.3 mg/liter and measured with optical sensors that could accurately determine very low DO based on oxygen-quenched luminescence. The strain was found to perform aerobic denitrification; while the specific rate decreased with increasing DO, denitrification persisted at approximately 1/8 of the maximum rate (1.7 mmol/g of cells/h) even at relatively high DO (1 to 1.3 mg/liter). In the presence …
High-Temperature Fiber Matrices: Electrospinning And Rare-Earth Modification, W. Kataphinan, R. Teye-Mensah, Edward A. Evans, R. D. Ramsier, D. H. Reneker, D. J. Smith
High-Temperature Fiber Matrices: Electrospinning And Rare-Earth Modification, W. Kataphinan, R. Teye-Mensah, Edward A. Evans, R. D. Ramsier, D. H. Reneker, D. J. Smith
Chemical, Biomolecular, and Corrosion Engineering Faculty Research
We demonstrate the production of nonwoven mats of high-temperature organic and inorganic fibers by electrospinning. Specifically, glass/ceramic (tetraethylorthosilicate-SiO) and fire-blanket (polydiphenoxyphosphazene-PDPP) precursors are electrospun, and the resulting fibers are characterized by scanning electron microscopy, thermogravimetric analysis, and infrared (IR) spectroscopy. We find that the SiO fibers are smaller in diameter and more uniform than the PDPP fibers, and stable to higher temperatures. We also coat these fiber systems with several rare-earth nitrates, and find that these coatings can be used to selectively modify the near-IR spectra of the fibers. This work extends the use of electrospinning into two new classes …
Nanoscale Oxidation Of Zirconium Surfaces: Kinetics And Mechanisms, N. Farkas, G. Zhang, Edward A. Evans, R. D. Ramsier, J. A. Dagata
Nanoscale Oxidation Of Zirconium Surfaces: Kinetics And Mechanisms, N. Farkas, G. Zhang, Edward A. Evans, R. D. Ramsier, J. A. Dagata
Chemical, Biomolecular, and Corrosion Engineering Faculty Research
We show that atomic force microscope-induced oxide features can be formed reproducibly on both Zr and ZrN surfaces, and that the growth rate decreases rapidly with increasing time. There is an increase in oxide-feature height with humidity for both systems, and an approximately linear dependence of the height of the structures on the applied voltage for all films for short exposure times. As the anodization time increases, only the thinnest (6 nm) films show a large enhancement in oxide-feature height, demonstrating the role of the film/substrate interface. Under the same conditions, the height of features grown on ZrN films is …