Bacterial Inactivation Kinetics of Dialdehyde Starch Aqueous Suspension

The bacterial inactivation kinetics of dialdehyde starch (DAS) aqueous suspension was studied by the relationship between the minimal lethal concentration (MLC) and the inactivation time at four different temperatures. The relationship between MLC and exposure time was found to follow the first-order Chick-Watson law. This first-order inactivation kinetics was modeled by pseudo-first order chemical reaction. This model was validated by the successful predication of the bacterial inactivation response at room temperature

Bacterial Inactivation Kinetics of Dialdehyde Starch Aqueous Suspension

The bacterial inactivation kinetics of dialdehyde starch (DAS) aqueous suspension was studied by the relationship between the minimal lethal concentration (MLC) and the inactivation time at four different temperatures. The relationship between MLC and exposure time was found to follow the first-order Chick-Watson law. This first-order inactivation kinetics was modeled by pseudo-first order chemical reaction. This model was validated by the successful predication of the bacterial inactivation response at room temperature

Synthesis and Pyrolysis of Novel Polysilazane to SiBCN Ceramic

A novel synthesis route was developed to produce exceptionally thermal stable SiBCN-based ceramics. This route turns out to be cheaper, simpler and faster than the conventional route. The SiBCN-based preceramic polymer was synthesized by using three monomers, trichlorosilane (HSiCl3), boron trichloride (BCl3), and hexamethydisilazane (HMDZ), at a molar ratio of about 1:1:4. The product becomes an amorphous structure with crosslinked bonds during the elimination of (CH3)3SiCl. An intermolecular condensation with the loss of HMDZ occurs in a second stage without the addition of crosslinking agents. In the final pyrolysis stage, hydrogen-rich species such as CH4 are lost. The chemical structure and composition of the obtained polymer were investigated using IR, MAS-NMR, TGA, DSC, XRD, EA, AA, ICP, and EDS. Through the pyrolysis of preceramic polymers, the mechanisms of the structural and compositional changes at a high temperature were also examined. A preceramic polymer useful for nuclear application can be formed, which provides hydrothermal stability under autoclave test

Mesoporous TMOS-MTMS copolymer silica gels catalyzed by fluoride

Mesoporous HF-catalyzed tetramethoxysilane-methyltrimethoxysilane (TMOS-MTMS) copolymer silica gels with average pore diameter from 80 to 100 Å and narrow pore size distribution have been obtained. Mesoporous TMOS-MTMS copolymer gels with tetramethoxysilane ranging from 10% to 100% were also produced with tetrabutylammonium fluoride (TBAF) catalyst. The pore sizes of TBAF-catalyzed copolymer gels were controlled over a range from 25 to 194 Å. Their pore sizes increased with increasing fluoride content to R2=0.112 (R2, molarratio of F/Si) and then level off. The catalytic effect of fluoride on the sol-gel process was investigated. The results suggest that multi-fluorinated silicon species catalyze the silica polymerization. © 2001 Elvier Science B.V. All rights reserved