When an external electric field is applied to poly(ethylene glycol) (PEG) particles suspended in silicon oil, an electrorheological (ER) effect is observed by which the viscoelastic properties of the suspension change. We previously found that PEG of low molecular weight enhanced the ER effect, which suggests that hydroxyl end groups rather than ether groups of main chains contribute to the effect. In this study, we synthesized PEG with acetate and carboxyl end groups and stearated PEG (Emanon) and studied the ER effect of these particle suspensions. Acetate and stearate resulted in a weaker ER effect than that of normal PEG (with hydroxyl end groups), whereas carboxylated PEG produced a stronger ER effect. The chain structure of carboxylated PEG particles in an external electric field was thicker than that of normal PEG. From the calculation of dipole moment of alcohol, esters and carboxylic acids, the difference in ER effect between PEG with various end groups was not caused by the strength of the dipole. When hydroxyl groups are esterified, hydrogen bonding among these groups disappears. However, because the carboxyl group has two hydrogen bonding sites, it is thought that the enhanced ER effect of the carboxylated PEG suspension was due to hydrogen bonding among particles.
The mixing performance of a BENDLEAF impeller was evaluated by the streak line visualization method developed by Inoue et al. (2009a, 2009b, 2012). The mixing performance of this impeller was different from that of other large paddle impellers developed by other Japanese companies. This impeller was able to mix highly viscous liquid with a shallower liquid depth. The optimum ratio of impeller diameter to vessel diameter d/D was about 0.6 or over, and mixing performance declined when d/D was under 0.5. The power number of the BENDLEAF impeller was correlated by the modified equation of the propeller and Pfaudler impellers.
In our previous studies, we reported that the flux change during nanofiltration (NF) of whey could be predicted by our theoretical analysis method. In this method, it is hypothesized that whey comprises both permeable and non-permeable solutes. Permeable solute can pass through an NF membrane but non-permeable solute cannot. We also found that the exchange of citric and phosphoric acids, amongst others, classified as non-permeable solutes, with chloride ions, classified as a permeable solute, by passage through an anion-exchange column in chloride form could increase the desalination ratio during NF of whey. In this study, we investigated whether our analysis method could be used to predict the flux change of anion-exchanged whey (IE whey). The ratio of non-permeable solute to total solute quantities in IE whey differed from that in the original whey, reflecting the difference in composition. The simulated fluxes matched measured values, indicating that our analysis method is useful for predicting flux change during NF of IE whey.
A mortar block was manufactured employing crushed granite sand, which was produced from Sanuki-shi, Kagawa, crushed copper slag and blast-furnace slag cement. After lying outdoors for several months, the surface of the mortar block was locally browned. To investigate this browning phenomenon, the following analyses were carried out: 1) chemical composition and crystalline compounds in the employed aggregates, 2) elemental (Si, Al, Fe, S) distributions in the aggregate and in the browned portion of the mortar block by EPMA, 3) identification of the browned component by IR. It was inferred that iron(III) sulfate, which was contained in a part of the crushed granite sand particles, was locally leached by contact with rainwater and reacted with Ca(OH)2 in the surrounding mortar to afford browned iron oxyhydoxide on the mortar block surface. The browning phenomenon also appeared when Fe2(SO4)3 impregnated sand was buried in a Portland cement mortar. As an effective measure against the browning, Fe leaching with acidic solution from the surface layer of granite sand was proposed.
In order to inject nanoparticles into cotton fibers, cavities in the fibers should be expanded. To expand the cavities, cotton fibers were immersed in 24 wt%NaOH aqueous solution for 1 h, and then dried at 100°C for 4 h. NaOH remaining in the fibers was then removed by washing. SEM revealed many cavities of about 500 nm in diameter in the cross sections of the cotton fibers. The cotton fibers were immersed in aqueous solution of 30 ppm silver nanoparticles, and the solution was maintained in an atmosphere of supercritical CO2 at 20 MPa and 80°C for 1 h. Many silver nanoparticles of 10–30 nm in diameter were observed in the cross sections by TEM. The cotton fibers with injected silver nanoparticles were washed with a magnetic stirrer for 3 h, after which the number densities of particles in the fibers were almost the same as before the washing, showing that the particles had not been washed out. In an antibacterial test on the cotton fibers with injected silver nanoparticles, the value of antibacterial activities after 6 h of washing was 5.7, showing that the antibacterial performance had hardly decreased.
The conditions of both global sustainability and prosperity of local communities must be fulfilled simultaneously in the formation of a sustainable society. To this end, application of academic knowledge in relevant fields such as chemical engineering is required, as well as cooperation among a diversity of stakeholders. In this study, we modeled the capacity of society needed for sustainability with three elements of hardware, software and humanware such as human consciousness and behavior, and examined the validity of the modeling through an analysis of a past international cooperation project. As a result, it was shown that a component to improve capacity related to humanware, which has not been always considered by designers as a project/program component, can have a significant impact on the capacity of society.