The interaction forces between like-charged colloids in 0.1 and 0.001 M NaCl aqueous solutions were calculated by molecular dynamics (MD) simulations with an implicit solvent model based on the potentials of mean force. The resultant forces were in good agreement with the theoretical predictions based on the Poisson–Boltzmann equation with a suitable approximation, demonstrating that the interactions between charged colloids in aqueous electrolyte solutions can be computed by our simulation methodology. Also, our MD simulations can visualize the overlap of the electric double-layers formed around the charged colloids, which is difficult to depict by theoretical treatment.

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This paper presents a method to solve equations with high-order schemes for convective term. The method was examined for a computational domain involving non-computational cells. First, a value for a cell face was given by QUICK and a second-order upwind method based on the finite volume method in the case of a non-uniform grid, and disretized equations were formulated. Second, the matrix equations were formed by using the discretized equations in the computational domain involving non-computational cells. This method was applied to a cavity flow and backward-facing step flow, and high accuracy was shown in both calculations. Furthermore, a duct flow with pillars in a staggered arrangement was also numerically analyzed. As a result, it was shown that this method is effective for complex geometries.

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Mixing experiments were conducted by performing image analysis of tracer particles for double-blade kneader mixers with various types of mixing vessels and blades. A method of assessing the processes of macro- and micro-mixing for wet particle systems was established, and this method was applied to the assessment of mixing performance of double-blade kneader mixers.
The relationship between the shapes of R(r) curves that represent the degree of mixing proposed by Danckwerts and aspect ratios of segregations were investigated, where R(r) is the correlation coefficient used to calculate the scale of segregation for the two measured points of separated by the distance r.
The difference of degree of mixing between actual and ideal R(r) curves was defined as the distortion degree of mixing.
For these analyses, we developed a procedure for analyzing the measured images of mixing processes of wet particles accompanied with tracer particles of almost the same sizes as wet particle sizes at an appropriate magnification corresponding to the state of micro-mixing at particle-size level.
As a result, it was shown that micro-mixing could be assessed through detailed investigation of particle mixing processes in which the scale of segregation decreases and the aspect ratios of segregation approach the specific value of particle.

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The behavior of particles during sieving was analyzed by 3-D simulation (Particle Element Method) to predict the separation size of sieves. The separation size of sieves varies according to the conditions, such as the vibration of sieving machines and the characteristics of sieved powders. To clarify the cause of this variation, the current research focused on the sieving rate and the number of trials in a unit time of sieving, ξ. In the case of horizontal vibration sieving, ξ increases as the centrifugal effect, K, increases. The sieving rate also increases and reaches its maximum value when K is approximately 2. On the other hand, ξ decreases as the particle size distribution becomes coarser and the quantity of sieved powder increases. Based on these results and the microscopic observation of particle behavior during sieving, the effect of sieving conditions on ξ was clarified. Consequently, a new method to predict the separation size is proposed.

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Economic evaluation of a membrane-absorption hybrid system for separation of CO₂ from a natural gas-fired power plant was performed. In this system, the feed gas (CO₂/N₂ mixture) and carrier solution (aqueous mixed solution of diethanolamine and 2-(butylamino)ethanol) are both supplied to the lumen side (feed side, high pressure side) of the hollow fiber ultrafiltration membrane module and flow upward. The carrier or absorbent solution, which contains dissolved CO₂, permeates the membrane to the permeate side (low pressure side, shell side), where the solution liberates dissolved gas to become a lean solution, and the lean solution is recycled to the lumen of the hollow fiber. In case 1, where the CO₂ purity of the recovered gas is higher than 90% and the recovered gas is transported as a gas mixture for sequestration, the energy required for CO₂ separation was estimated as 0.10 kWh/kg-CO₂, and the CO₂ separation cost including energy cost and equipment cost was estimated as 3.09 yen/kg-CO₂. In case 2, where the recovered CO₂ is transported as liquefied gas, the required energy and separation cost were estimated as 0.22 kWh/kg-CO₂ and 5.14 yen/kg-CO₂, respectively. These values were smaller than the corresponding values of conventional CO₂ separation processes such as chemical absorption process and polymeric membrane separation process, which suggested that the present CO₂ recovery system has an economic advantage over the conventional CO₂ separation processes.

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When involatile salts are added to an azeotropic mixture, the so-called salt effect changes the vapor–liquid equilibrium, and has a big influence on relative volatility. Aqueous nitric acid is an azeotropic mixture, and cannot be concentrated by ordinary distillation. In this study, we measured the vapor–liquid equilibrium of nitric acid–water–nitrate salt systems with azeotropic composition (x=0–40 mol%) for recycling of nitric acid in solutions from semiconductor manufacturing and metal-surface treatment processes. Aluminum nitrate, magnesium nitrate, calcium nitrate, lithium nitrate and sodium nitrate were used as nitrate salts. For each salt tested the salting-out effect was confirmed and the azeotropic point was eliminated completely by adding salts at concentration of 30–50 wt%. Consequently, nitric acid could be separated by distillation from waste solution with a low concentration (under azeotropic composition) of nitric acid. Separation and concentration of nitric acid from dilute aqueous nitric acid was tested by simple distillation using 50 wt% lithium nitrate. As a result, nitric acid aqueous solution was concentrated from 5.0 to more than 14.0 mol/dm³ (yield, 72.2%).

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This paper presents an efficient and accurate numerical method for estimating transient temperature profile of hot spot in a catalytic packed bed reactor. The method employs an extended Kalman filter and a dynamically adaptive grid technique. Distinct from the conventional fixed grid method, the adaptive grid method dynamically generates grids for calculation based on the state distribution. This technique is a useful tool increasing the accuracy and reducing computational costs for solving partial differential equations.
Simulated results for a packed bed reactor showed that the proposed method gives more accurate estimation of the hot spot temperature distribution than the conventional fixed grid based an extended Kalman filter without increasing the computation cost.

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We proposed a liposome immunosorbent assay (LISA) and a liposome immune lysis assay (LILA) for competitive measurement of an antigen by use of antigen-coupled liposomes encapsulating fluorescent marker carboxyfluorescein (CF) and clarified the effects of measuring conditions on the assay characteristics. With increase in the spacer length of hetero-bifunctional reagents used for cross-linking reaction, the amount of CF released from liposomes on coupling of antigen molecules with activated liposomes increased. The sensitivity in the LISA was affected by the amount of the antigen coupled on the liposomes and the concentration of the antigen present in assay solutions. This competitive LISA could detect two orders of magnitude lower concentration than the conventional ELISA and could measure over five orders of the antigen concentration. Since the competitive LISA required only one washing step for B/F separation, it was useful for rapid and easy measurement of antigen with high sensitivity. By competitive LILA using antigen-coupled liposomes, the concentration of antigen could be measured successfully, though the minimal detectable antigen concentration by the competitive LILA was higher than that by ELISA.

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A rule was derived for constructing the unit element of a static micromixer that performs multiplexing of fluid layers by combining splitting, 180° rotation and recombining-superposition in 3D bent channels. Based on the rule, a Y-type plate static mixer was developed, which consists of a combination of a Y-branch, 120° and 60° bent channels with rectangular cross-section and circular channels interconnecting these rectangular channels. The number of unit elements required for complete mixing ‘n’ was measured for a Y-type static mixer with square cross-section by conducting a decolorizing reaction with iodine. In the case of low Reynolds numbers, the element number n increased with Re. By modeling the mixing process in a fluid layer whose thickness reduces by half after the fluid passes through each unit element, a functional relation was derived to express n, based on which the experimental results for n at small Re were correlated. In the case of high Reynolds number, n decreased with Re, and the behavior was correlated experimentally with the variables in the functional relation. CFD analysis was conducted at Reynolds number up to 50. The results at Re=50 showed that fluid layers are deformed largely by secondary flows generated in the 3D bent channels, which promote mixing rate and decrease n with Re. Effects of the aspect ratio, a/b, of the rectangular cross-section of the mixer were investigated by CFD calculation. Deformation of the fluid interface is large for a/b≥2.0, and splitting does not progress uniformly in the branch channel for a/b≤0.2. Hence it is recommended to adopt channels whose cross-section is as close to a square as possible for promoting ideal splitting and recombination of fluid layers in the plate static mixer developed in this study.

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AFI-type structure ferroaluminophosphate zeolite (FAPO–5) was examined as an AHP adsorbent. FAPO–5 with iron content of 2–8 mol% (Functional Adsorbent Material-Zeolite 01; FAM–Z01) was selected for further testing. The water vapor adsorption isotherm of FAM–Z01 was S-shaped and highly dependent on temperature, and almost no hysteresis was observed with adsorption/desorption at 333 K and 348 K. No changes were observed in the properties of FAM–Z01 after 200,000 cycles of water vapor adsorption-desorption, indicating that FAM–Z01 is suitably durable for practical use. When the AHP was operated under conditions of T_L/T_M/T_H=283 K/303 K/333 K, the adsorption capacity of FAM–Z01 was 4 times that of silica gel.

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Wastewater containing Cr³⁺ and organic matter from chromate(III) treatment was oxidized by ozone combined with ultraviolet (UV) radiation. The treated water containing Cr⁶⁺ after the oxidation process was purified by passing through a cation exchange resin column and then through an anion exchange resin column. This combined process increased the production of pure water volume compared to a single process using an ion exchange resin. Electric conductivity of effluent water from the anion exchange resin column was less than 20 µS/cm. This deionized water can be reused as rinsing water in the chromate(III) treatment process.
Concentrated Cr⁶⁺ discharged upon regeneration of the anion exchange resin was refined by a new ion exchange resin method which was developed in order to exclude chloride ions selectively. Cr⁶⁺ solution with high purity and low contents of chloride ion was recovered from this solution. Based on these experiments, we devised a practical recycling system by which water in toxic Cr⁶⁺ wastewater can be reused as de-ionized water on an industrial scale at a plating factory, and Cr⁶⁺ in the wastewater can be recovered as raw material for chromium products.

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Lead-free glasses with a low melting temperature (less than 600°C) and good chemical durability are desirable for the sealing process in ceramic and electronic applications. In this study, V₂O₅, ZnO, BaO, and P₂O₅ were used to prepare lead-free glasses with a low-melting temperature. The glass forming region, glass transition temperature, softening temperature, thermal stability, X-ray property, and thermal expansion property were investigated in detail in the quaternary system. The dependencies of these properties on composition were quantitatively characterized. The lead-free glass, 34.7 mol%V₂O₅, 12.9 mol%ZnO, 20.6 mol% BaO and 31.8 mol% P₂O₅ had high chemical stability, an amorphous structure, high water resistance, and a low melting point. In a sealing examination with a plane fluorescent lamp incorporated in a digital camera, we succeeded in achieving excellent sealing. The prepared lead-free glass exhibited a high performance as a substitute for the commercially available lead glass

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