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Effect of eccentrically located position of impeller on mixing time was investigated in agitated vessels of different bottom shapes. The impellers used were a 4-bladed propeller and a 6-bladed flat paddle, which were commonly used in process industries, and the bottom shapes tested were a cone-fillet, a fully profiled and an ellipsoid bottom in addition to a flat bottom. The effect of off-bottom clearance of impeller on mixing time was also investigated at optimum eccentric locations for both impellers. For propeller, mixing times for all eccentric location covered in this work (e/R = 0.25–0.50, e: distance from shaft to center line of tank, R: radius of tank) became short drastically compared to those for centrally located for all bottom shapes and there was no significant effect of bottom shapes on mixing time. On the other hand, for flat paddle, mixing times were decreased proportionally with an increase in e/R. At optimum eccentric locations, those are e/R = 0.33 for propeller and 0.50 for flat paddle, the mixing times for propeller decrease drastically and then increase slightly with an increase in off-bottom clearance for all bottom shape and those for flat paddle decrease almost proportionally with an increase in off-bottom clearance but differed more or less according to the bottom shapes.

From a lot of survey, it is obvious that most students in universities lose their desire for learning just after entering their universities. In order to solve this problem, we developed a novel educational tool for the students, named “The thinking method based on matrix diagram” . If they try hard with the help of this tool, they will be able to learn how to design and manage their splendid university lives in addition to get the basic knowledge and to improve their basic abilities. It is also found that they can earn the shared knowledge mutually after learning a common method, which supports to make them to improve their communication abilities drastically.

In this work vertical dual-array tubular coil baffles arranged in groups of four, six or eight were investigated and the results compared with those from four planar baffles. The baffle coefficients for a single phase, along with the power consumption and gas hold-up in the gas-liquid phase of a system with the various baffle configurations for single and triple Rushton turbines are presented. Measurements were carried out using a dish-bottom vessel with an inner diameter of 0.29 m. Two ambient-temperature media were used as the liquid phase, namely, tap water and a 0.5 M Na2SO4 aqueous solution, representing coalescent and non-coalescent liquids, respectively. The results of the single-phase experiment revealed the coil baffles to have lower power numbers; when the baffle coefficient is ≥ 0.12, the mixing efficiency is the same as that for four planar baffles. The power consumption experiment using the gas-liquid phase showed that installing coil baffles prevented a large power draw in all types of media. In addition, the power draw characteristics are affected by the media. It was found that, because of the low KB number, flooding occurred more readily with coil baffles than with planar baffles. Gas-liquid dispersion experiments in an air-water system indicated that, at a low gas flow-rate, the gas hold-up values of the coil baffles were almost 60 % higher than those of the conventional four baffles. However, this phenomenon was not observed in the Na2SO4 aqueous solution because of the existence of dead zones in viscous liquids. Finally, all the data from the power consumption and gas hold-up experiments on the gas-liquid phase were correlated.

Porous particles of oxides of transitional metals, such as copper, nickel, cobalt, iron, manganese, and chromium, were prepared in single and binary mixtures by the freeze-drying process to serve as combustion catalysts. Aqueous metal sulfate solutions of the above metals were utilized as raw material for freeze-drying. Spherical drops of the solutions were instantly frozen in a cooled bath. The frozen particles were dried in a vacuum chamber. These were then calcined into particles of single and double oxides, as well as oxide mixtures. The open porosity within the freeze-dried particles induced by sublimation of ice crystals was retained during calcination and the subsequent firing. Methane/air was combusted in an adiabatic tubular reactor in the presence of the porous oxide particles to determine the particles' catalytic activity. The feed gas equivalence ratio and residence time were kept constant while methane conversions were measured as a function of gas temperature. The activity of the catalysts was assessed based on the temperature during the surface-kinetics-controlled regime. Among the catalysts examined, the strongest were binary oxides of cobalt and nickel.

Mixotrophic culture of Euglena gracilis was carried out using a fed-batch culture system. Glucose and L-glutamic acid were added every 24 hours for 6 days to make the concentrations in the culture medium return to their initial values. We proposed a mixotrophic growth kinetics model to correlate a specific growth rate with a specific rate of energy consumption. In the model, the specific growth rate was proportional to the (1/n)th power of the specific energy consumption rate, and a corresponding yield parameter and a maintenance factor depended on light intensity. The specific growth rate in mixotrophic culture was correlated with incident light intensity by an equation that combined pseudo-photoautotrophic growth rate comparable to that of the modified Aiba model with heterotrophic growth rate. The optimum light intensity that produced the attainable maximum growth rate in mixotrophic culture could be estimated by the equation.

A new technique for preparing magnesia ceramics of high porosity and high temperature resistance has been developed. Spray freeze drying of magnesium sulfate aqueous solution produced fine salt particles having open pores due to sublimation of ice crystals. The particles were calcined to porous magnesium oxide and formed a green body. Highly porous magnesia was produced by firing the green body. The porous magnesia exhibited a bimodal pore size distribution of macro-pores of micron order and meso-pores smaller than 100 nm. Porosity was 87–90%. After addition of an aluminum additive with an amount 3–5 mol%, the magnesia exhibited high heat resistance; surface area was greater than 20 m 2 g −1 after 20 h exposure in a 1573 K oven. Thus, the porous magnesia is expected to be very suitable for combustion catalyst support used in a high temperature environment.

Ruthenium complexes [RuII (bpy) 3] Cl2, [RuIII (H2O) (NH3) 5] Cl3, [RuIIICl (NH3) 5] Cl2, [(bpy) 2 (NO2) RuIIIORuIII (NO2) (bpy) 2] (ClO4) 2 and [(bpy) 2 (H2O) RuIIIORuIII (H2) (bpy) 2] (ClO4) 4 were used for the visible-light photocatalysts in the decomposition ofwater.The photocatalysts were systematized in an ITO/Nf (Ru (bpy) 3) /Pt/Me multilayer, where Me represents [RuIII (H2O) (NH3) 5] Cl3, [RuIIICl (NH3) 5] Cl2, [(bpy) 2 (NO2) RuIIIORuIII (NO2) (bpy) 2] (ClO4) 2, or [(bpy) 2 (H2O) RuIIIORuIII (H2O) (bpy) 2] (ClO4) 4, and Nf (Ru (bpy) 3) denotes the [RuII (bpy) 3] ion incorporated into Nafion (ion-exchange membrane). Whenthe ITO (electrically conductive glass) was polarized anodically and irradiated with visiblelight, water was oxidized to form oxygen on the Me area

A statistical approach is still the most effective tool for handling coupled absorbing and scattering phenomena in a heterogeneous system for the assessment of light energy absorption in a photoreactor. A Monte Carlo simulation model has been developed for the prediction of light intensity distribution in a photoreactor. The model has three parameters, an attenuation coefficient, a probability of light ray absorption, and a scattering parameter which specifies the mode of isotropic and/or anisotropic scattering. Experimental measurements of light transmittance and reflectance through solid particle suspensions bounded by two infinite plates were carried out using a newly designed integrating sphere device attached to a spectrophotometer. Light intensity distributions in a rectangular photoreactor with the suspension irradiated by a laser beam were also measured with a photo-probe. These data are compared with simulation results and model parameters are determined to satisfy the experiments. Light absorption fractions measured in the suspensions with different optical lengths show satisfactory agreement with those estimated by the simulation. Thus, the model developed is verified to be effective for the assessment of light absorption rates in a heterogeneous photoreactor.

Effects of five types of nonionic surfactant having a polyoxyethylene glycol (POG) group on enzymatic hydrolysis of used newspaper were studied. The surfactants examined in this work always enhanced the saccharification. The optimum surfactant concentration was 0.05% (wt/substrate wt) in the case of POG(21) sorbitane oleic ester. Among the surfactants, POG phenyl ether types showed the highest enhancement effect, for example, with two times higher conversion at 80 h than that without surfactant. Using POG nonylphenyl ether series, the effects of surfactant were considered from the point of the HLB (hydrophile-lypophile balance) value. The GFC (gel filtration chromatography) analysis of free enzyme quantity were also done to study the effect of surfactant on enzyme adsorption onto substrate. As the HLB value increased, the free enzyme quantity and the conversion both increased. It appears that surfactants help the enzyme to desorb from the binding site on the substrate surface after the completion of saccharification at that site.

This paper presents an application of gel filtration chromatography (GFC) as a convenient method of monitoring the cellulase production process. The relationship between GFC chromatogram and activity of cellulase, such as Avicelase, FPase, CMCase and β-glucosidase, is also discussed

A new random-walk model was proposed to simulate light scattering in a solid–liquid photoreactor. The light intensity in the reactor could be estimated by a model in which two significant parameters represented non-isotropic scattering and light absorption by a solid particle. Comparison between the results of scattering simulation and chemical actinometric experiments confirmed the validity of the model.

In a helical ribbon agitator, mixing patterns and mixing times for two miscible, highly viscous Newtonian liquids with different viscosities are investigated. From the observed mixing patterns, empirical correlations for mixing time are obtained as functions of the Reynolds number and a dimensionless number defined by the ratio of gravitational to viscous force. The optimum operational conditions for the mixing process are predicted from these correlations.

Photo-oxygenation of 2,3-dimethyl-2-butene was performed using dye-supported solid particles as photosensitizer. Quantitative effects of solid sensitizer concentration and of dye quantity supported on solid particles were investigated. The light absorption rate in the heterogeneous system was assessed by a Monte Carlo simulation. The reaction rate was proportional to the n-th order of light absorption rate, where n was a little less than unity, and to the 0-th order of butene concentration in a feed range of 5 × 101–2 × 102 mol/m3. The rate constant was a function of dye quantity supported on solid particles. This is due to the adsorbate–adsorbate interaction.