Synthesis gas is a high valued compound as a basic chemicals at various chemical processes. Synthesis gas is mainly produced commercially by a steam reforming process. However, the process is highly endothermic so that the process is very energy-consuming process. Thus, this study was carried out to produce synthesis gas by the partial oxidation of methane to decrease the energy cost. The effects of reaction temperature and flow rate of reactants on the methane conversion, product selectivity, product ratio, and carbon deposition were investigated with 13wt% Ni/MgO catalyst in a fluidized bed reactor. With the fluidized bed reactor, CH4 conversion was 91%, and Hz and CO selectivities were both 98% at 850℃ and total flow rate of 100 mL/min. These values were higher than those of fixed bed reactor. From this result, we found that with the use of the fluidized bed reactor it was possible to avoid the disadvantage of fixed bed reactor (explosion) and increase the productivity of synthesis gas.
The effects of reaction temperature and flow rate of reactants on the methane conversion, product selectivity, product ratio, and carbon deposition were investigated with 13wt% Ni/MgO catalyst. Reaction temperatures were changed from 600 to 850℃, and reactants flow rates were changed from 100 to 200 mL/mim. There were no significant changes in the methane conversion observed in the range of temperatures used. It is possibly stemmed from the nearly total exhaustion of oxygen introduced. The selectiveties of hydrogen and carbon monoxide did not largely depend on the reaction temperature. The selectivities of hydrogen and carbon monoxide were 96 and 90%, respectively. Carbon deposition observed was the smallest at 750℃ and the largest at 850℃. It is found that the proper reaction temperature is 750℃. The best reactant flow rate was 150 ml/min.
There were two purposes of this study. The first was to research the effects of standard and fixed-split keyboards on wrist posture and movements during word processing. The second was to select optimal computer input devices in order to prevent cummulative trauma disorder in the wrist region. The group of subjects consisted of thirteen healthy men and women who all agreed to participate in this study. Kinematic data was measured from both wrist flexion and extension, and wrist radial and ulnar deviation during a 20 minute period of word processing work. The measuring tool was an electrical goniometer, and was produced by Biometrics Cooperation. The results were as follows: 1. The wrist flexion and extension at resting starting position were not significantly different (p>.05), however the angle of radial and ulnar deviation were significantly different in standard and split keyboard use during word processing (p<.05). 2. In the initial 10 minutes, the dynamic angle of wrist flexion and extension were not significantly different (p>.05), however the dynamic angle of radial and ulnar deviation was significantly different in standard and split keyboard use during word processing (p<.05). These results suggest that the split keyboard is more optimal than the standard keyboard, because it prevented excessive ulnar deviation during word processing.
This study deals with the case of a fixed floating structure(FFS) at the mouth of a rectangular harbor under the action of waves represented by the linear wave theory. Modified forms of the mild-slope equation is applied to the propagation of regular wave over constant water depth. The model is extended to include bottom friction and boundary absorption. A hybrid element approximation is used for calculation of linear wave oscillation in and near coastal harbor. Modification of the model was necessary for the FFS. For the conditions tested, the results of laboratory experiments by Ippen and Goda(1963), and Lee (1969) are compared with the calculated one from this model. The cases of flat cylinderical structures, both fixed and floating, were taken to be in an intermediate water depth.