Showing papers by "Paul F. Greenfield published in 2000"
TL;DR: In this paper, a chemical vapor deposition (CVD) method was used to load TiO2 onto a bigger particle support, silica gel, and the amount of titania coating was found to depend strongly on the synthesis parameters of carrier gas flow rate and coating time.
Abstract: TiO2 in anatase crystal phase is a very effective catalyst in the photocatalytic oxidation of organic compounds in water. To improve the recovery rate of TiO2 photocatalysts, which in most cases are in fine powder form, the chemical vapor deposition (CVD) method was used to load TiO2 onto a bigger particle support, silica gel. The amount of titania coating was found to depend strongly on the synthesis parameters of carrier gas flow rate and coating time. XPS and nitrogen ads/desorption results showed that most of the TiO2 particles generated from CVD were distributed on the external surface of the support and the coating was stable. The photocatalytic activities of TiO2/silica gel with different amounts of titania were evaluated for the oxidation of phenol aqueous solution and compared with that of Degussa P25. The optimum titania loading rate was found around 6 wt % of the TiO2 bulk concentration. Although the activity of the best TiO2/silica gel sample was still lower than that of P25, the synthesized TiO2/silica gel catalyst can be easily separated from the treated water and was found to maintain its TiO2 content and catalytic activity.
190 citations
TL;DR: Low multiplicity infections were found not to cause any significant dispersion of the protein production process, and product stability is not a major issue of concern using low multiplicities of infection, supporting the existing view that batch cultures are limited by availability of substrate.
Abstract: In vitro infection of insect cells with baculoviruses is increasingly considered a viable means for the production of biopesticides, recombinant veterinary vaccines, and other recombinant products. Batch fermentation processes traditionally employ intermediate to high multiplicities of infection necessitating two parallel scale-up processes-one for cells and one for virus. In this study, we consider the use of multiplicities of infection as low as 0.0001 plaque-forming units per cell, a virus level low enough to enable infection of even large reactors (e.g., 10 m(3)) directly from a frozen stock. Using low multiplicities in the Sf9/beta-gal-AcNPV system, recombinant protein titers comparable with the maximum titer observed in high multiplicity infections were achieved. Cultures yielding the maximum titer were characterized by reaching a maximum cell density between 3 and 4 x 10(9) cell L(-1). This optimal cell yield did not depend on the multiplicity of infection, supporting the existing view that batch cultures are limited by availability of substrate. Up to a certain cell density, product titer will increase almost linearly with availability of biocatalyst, that is, cells. Beyond this point any further cell formation comes at the expense of final product titer. Low multiplicity infections were found not to cause any significant dispersion of the protein production process. Hence, product stability is not a major issue of concern using low multiplicities of infection. The sensitivity to initial conditions and disturbances, however, remains an issue of concern for the commercial use of low multiplicity infections. (c) 1996 John Wiley & Sons, Inc.
115 citations
TL;DR: In this article, in situ respirometry was used as an indicator of microbial activity and substrate utilisation in a sequencing batch reactor (SBR), which enabled the determination of an optimum operating cycle for the effective treatment of synthetic wastewater containing up to 1300 mg/l phenol as the sole carbon source.
76 citations
TL;DR: A kinetic model was developed to describe the effect of the crystal size and titania concentration on the reactivity of the SiO (2)-TiO(2) samples and it was found that k(s) decreases with increasing anatase size and TiO( 2) concentration.
50 citations
TL;DR: In this paper, an improved operational strategy to enhance methane production was determined in a single-stage digester, taking advantage of the different rates of biomethanation and biochemical methane potentials of different layers of the slurry.
40 citations
TL;DR: In this paper, the authors examined how Australian high technology companies approach the synergy between corporate R&D and strategic management and found that the companies have been aware of the importance of integrating decision making with corporate strategic management.
17 citations