The physical and chemical characteristics of micro bubbles were investigated and some best practices of the micro bubble technology were reviewed concretely. The distribution, shrinkage process, rising velocity, and electric potential of micro bubbles were examined. An action of the physiological activity which forms large amounts of insulin like factor-1 is induced in the body of mice by the supply of micro bubbles as a sensorineural stimulation in the bubble bath. Further, the micro bubble technology makes an advance into the fields of cleaning process of semiconductor material and wastewater treating in some semiconductor manufacturing factories. Moreover, this technology works on the biological environmental improvement and water purification in closed water area.

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Tube mills having four kinds of liner designs (MODEL I, II, III and IV) were modelled to evaluate the effect of liner design on the impact energy by the Discrete Element Method (DEM). The ball charge motion was simulated, and the impact energy of balls was calculated. The charge motions of MODEL I (duolift), III (step wave liner) and IV (lifter liner) were cataracting and cascading, and motion in MODEL II (steps) seemed to be cascading under the condition of N/N_C = 0.72 (N_C: critical rotational speed). MODEL I, III and IV gave larger impact energy than that of MODEL O (without liner). MODEL III had the largest E_n (normal component of impact energy) in all mills; and it was 32% superior to MODEL O. The distribution of E_n shifts to high-energy range when the mill had liner. The effective area for the grinding in MODEL I, III and IV were around toe of ball charge due to cataracting motion. Therefore, the grinding performance will be improved by the liner, especially design of MODEL III is the best according to this analysis.

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The feasibility of making ferrite at ambient temperature from aqueous solutions of simulated acid mine drainage was investigated following our previous report. In this paper, qualitative and quantitative effects of coexisting ions such as Mn(II), Zn(II), Al(III) and Si(IV), on ferrite formation were investigated.
As the first step, influences of several coexisting ions on the settling volume of the precipitates were investigated. In the case of Mn(II) or Zn(II) coexisting system, which are well known to have the capacity to substitute to the part of the lattice of ferrite, the settling volume increased a little, but in the case of Al(III) or Si(IV) coexisting system, which are known to impede ferrite formation, the settling volume considerably increased. However, the interference of Al(III) or Si(IV) to ferrite formation was weakened in the sludge recycling system.
Secondly, their influences on the yield of magnetite or ferrite, which are calculated by the total oxygen consumption in the aerial oxidation reaction test, were investigated. The yield of magnetite decreases with an increase of Al(III) or Si(IV), but their interferences on ferrite formation were weakened in the presence of restored magnetite seed.
Thirdly, their influences on the reaction rate in the aging process were also examined by solid-solid reaction test in which Fe(OH)₂, FeOOH and coexisting ions reacted directly in reduction atmosphere and at a fixed pH. The reaction coefficient considerably decreased not only by Al(III) or Si(IV), but also by Mn(II) or Zn(II), which are estimated not to impede ferrite formation.

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Photocatalytic oxidation of cyanide ion was investigated using two type of TiO₂ catalysts; Sample A, fine powder of anatase and rutile, and Sample B, pure anatase ultrafine powder. Cyanide ion was oxidized to CNO^-, and subsequently to NO₃^- and CO₃^2- ions with both catalysts. With Sample A, CN^- oxidation proceeded faster at higher initial concentration of CN^- and at lower initial concentration of KOH. In contrast, with Sample B, CN^- oxidation was faster when initial concentration of CN-, but KOH initial concentration effect appeared reversely. From there finding the authors proposed the different routes for sample A and B. On the other hand, the oxidation of CNO^- was faster despite of type of catalyst was used when initial KOH concentration was low. In the experimental range of present work, suitable range of quantity of photocatalyst used exists, and UV intensity affect linearly for oxidation of CN^- to CNO^-.

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Chlorinated organic compounds such as trichloroethene (TCE) have caused soil and ground water pollution on a lot of sites. Oxidation processes which are produced hydroxyl radical are effective to remediate these contaminated sites, because they are able to degrade TCE. This paper describes photochemical oxidation of TCE with citrate ion and iron ion. Citrate ion and iron ion form some complexes (Fe-citrate complexes) which absorb the light of wavelength below 450nm. The Fe-citrate complexes were able to be decomposed TCE with black light lamp (wavelength: 320-400 nm). Approximately 50% of initial TCE concentration (100mg/L) decomposed within about 7 hours when the molar ratio of iron ion to TCE is 4 and the molar ratio of citrate ion to TCE is 4. The degradation rate of TCE using citrate ion and iron ion was lower than using oxalate ion and iron ion. The excess iron ions inhibited the TCE degradation because some of iron ions formed iron hydroxide and it absorbed lights essential for the photochemical reaction. Therefore, the photodegradation of TCE needs sufficient citrate ion to ensure for forming Fe-citrate complex formation. TCE was degraded between initial pH 2.5 and 10.6. The degradation rate of TCE was higher in the condition of acidity than the condition of alkalinity. In acidic condition, the dominant iron species was [Fe(III)(C₆H₅O₇)] which is the important species for TCE photodegradation. On the other hand, even in alkaline condition, [Fe(II)(C₆H₅O₇)]^- existed as an Fe-citrate complex. So, this fact shows strongly that [Fe(II)(C₆H₅O₇)]^- photochemically degrades TCE under the condition of alkalinity.

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The analyses on the resource and recycling problems of indium elements have been conducted. The electronic industry uses 80% of the total indium production in the world as ITO (indium tin oxide) for flat display panels. The refinery and application processes, material flow, present status of the resources, and recycling have been analyzed based on the data in 2003. The production shift and other items from 2003 to 2025 were estimated through 3 scenarios. The resources will be exhausted by 2010 if the current resource estimation is correct and production rate continues. The exhaustion will occur around 2025 or before even if recycling and technology advance, by which the amount of In used in flat panel displays can be reduced are developed. The toxicity of indium is uncertain as of now , but the mass flow in Japan is not very high, so the effect on pollution in Japanese society is expected to be very low. The price of indium is plotted on the line of the prices as a function of the separative work units of Fe, Cu, Zn, Ag, Au. This means that the price is reasonable although there is little resource and the usage is limited in flat display panels. The production, price and exhaustion will be strongly affected by zinc refinery, alternative technologies in the electronic industry and recycling technologies and systems.

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