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In the present study, metal-ion-doped TiO 2 powders were prepared by a sol-gel process using titanium isopropoxide as a Ti precursor and cobalt, gallium, or neodymium as a dopant. For the prepared doped TiO 2 nanopowders, the photocatalytic behaviors in the decomposition of aqueous 1,4-dichlorobenzene (DCB) were investigated as a function of doping level and preparation conditions. We found that all of the metal ion doping improved the photocatalytic activity of TiO 2 , though Nd doping was the most effective and Co doping was least effective. XRD analyses showed that doping with Ga and Nd ions suppresses the anatase-to-rutile phase transition for TiO 2 , whereas doping with Co did not influence the phase transition. The UV-visible absorption spectra for these metal-ion-doped samples were red-shifted by ~20-40 nm depending upon the doping level.

Silica-embedded nanocrystalline TiO 2 powders were synthesized by sol-hydrothermal process. The influence of the composition of the solvent and the embedded silica content on the phase transition, grain growth and subsequently, on the photoactivity of TiO 2 were investigated. The volume ratio of ethanol to water for the solvent composition was varied from 0.125 to 8 and the mole fraction of silica content was changed from 0 to 0.4, while the condition for hydrothermal reaction was fixed at 250 • C for 2 hour. With an increase in ethanol content in solvent composition, the crystallite sizes of pure TiO 2 particles decreased from 15 nm to 6 nm and crystal phase changed from rutile/anatase mixed phase to pure anatase phase.Addition of silica to TiO 2 brought about an increase in the photocatalytic activity by suppressing the phase transition from anatase to rutile. Judging from the result of the decomposition of 1, 4-dichlorobenzene, the most efficient catalyst was found to be 0.2 mole fraction SiO 2 embedded TiO 2 prepared with ethanol-rich solvent (the volume ratio of ethanol to water is 4).

A centrifugal turbo blower is one of the important parts used for generating electric power in a fuel cell electric vehicle (FCEV). The impeller blades of the centrifugal turbo blower must rotate at a high speed to generate electric power. The unbalance and asymmetry of the rotating parts, such as impeller blades, become causes of the heavy vibration of the centrifugal turbo blower. This vibration is transmitted to the chassis frame of the FCEV through vibration isolators and becomes one of the major sources of interior noise in the FCEV. Therefore, the vibration generated from a centrifugal turbo blower should be attenuated properly to reduce the interior noise. To achieve this effectively, quantification of the vibration energy flow through the isolators is necessary, since it gives information on the quantification of the vibrational energy flow from the centrifugal turbo blower to the chassis frame. Information on the vibrational power flow at each vibration isolator identifies the vibration transmission path. In this paper, a simple equation is derived to calculate the vibration power flow through each vibration isolator. With this equation, the vibrational power flow through each isolator is numerically simulated. In this simulation, the vibration generated from the centrifugal turbo blower is predicted using the multi-body dynamic analysis of a three-dimensional model of the centrifugal turbo blower based on computer-aided engineering. These simulated results are confirmed by measurement of the vibration power flow generated from the centrifugal turbo blower in a laboratory.

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