Anionic graft copolymerization of methyl methacrylate with lithium diisopropylamide-treated poly(methyl α-substituted acrylate)s

The anionic grafting of methyl methacrylate onto several lithium diisopropylamide (LDA) — treated polymers of methyl α-substituted acrylates containing an active methylene or methine group was investigated. The grafting was carried out using a mole ratio of LDA/acrylate unit of 0.75 in the feed polymer. The anionic graft copolymerizability of these acrylate polymers largely depends upon the surrounding of the active α-hydrogen atom adjoining a carbonyl group or of the carbanion produced by the LDA treatment in the feed polymer.     

Synthesis and properties of poly(arylene ether sulfone)s and poly(arylene ether ketones) derived from 4,4″-dihydroxy-o-terphenyl

Novel poly(arylene ether)s with a rigid and zigzag 4,4″-o-terphenyldiyl structure, introduced into the polymer backbone were synthesized by nucleophilic displacement reaction of 4,4″-dihydroxy-o-terphenyl with several activated aromatic dihalides in virtually quantitative yields. The poly(arylene ether)s having high molecular weight show both good solubility in common organic solvents and high thermal stability up to 545°C. They are amorphous with glass transition temperatures of 160–200°C.     

Did Arsenic Contamination in the Inagawa River Occur in Geogenic Relation to the Great Hanshin (Kobe) Earthquake of 1995?

Arsenic contamination in river and ground water was investigated in the Inagawa area of Kansai district, Japan, from August to October, 1995. Arsenic has been continually detected at a level about 2 times higher than the environmental standard in the two tributaries of the Inagawa River, i.e. the Kimo and the Shio Rivers. The arsenic contamination was probably caused by the topographical change after the Great Hanshin Earthquake.     

Continuous ethanol extraction by pervaporation from a membrane bioreactor

In order to obtain a high productivity of ethanol, a membrane bioreactor consisting of a fermentor and a pervaporation system was applied to the continuous alcoholic fermentation process. A microporous hydrophobic polytetrafluoroethylene membrane was used for pervaporation. Glucose medium and baker's yeast were used for the fermentation. Three types of continuous fermentation experiment were carried out: conventional free-cell fermentation as the standard process; a fermentation in which product ethanol was extracted continuously by pervaporation from the membrane bioreactor; and a fermentation in which ethanol was extracted by pervaporation and part of the culture broth was simultaneously removed from the fermentation system.

The fermented ethanol was continuously extracted, and simultaneously concentrated by pervaporation, from the membrane bioreactor, and the extracted ethanol concentration was 6 to 8 times higher than in the broth. A high concentration of microorganisms was realized by immobilizing cells in the membrane bioreactor. When the ethanol concentration in the broth was kept low by pervaporation, the specific rate of ethanol production increased. However, the fraction of viable cells decreased because of the accumulation of inorganic salts fed as a nutrient, of nonvolatile by-products and of aged cells, which were not extracted by pervaporation from the fermentation solution. In order to achieve a high ethanol productivity, part of the fermentation broth must be removed from the membrane bioreactor.     

Surface electromigration of metals on Si(001): In/Si(001)

The possibility of surface electromigration (SE) of metals of In, Ga, Sb and Ag on a very flat Si(001)2×1 substrate (single domain 2×1) was examined by SEM, μ-RHEED and μ-AES under UHV conditions. It was found that Ga, Sb and Ag show no SE on Si(001) surface even at DC annealing temperatures for the desorption of these metals. For In on Si(001), a very fast SE (8000 μm/min) towards the cathode side was found that suddenly sets in at 450°C DC annealing, which was related to a surface phase transition. μ-RHEED and μ-AES observation showed that the SE is related to an ordered 4×3-In phase together with two-dimensional In gas phase over the 4×3-In phase and an In-disordered phase at the front end of SE. Single domain 4×3-In phases were found to occur under sequences of In deposition and DC annealing which involve the In SE on Si(001).     

PIV measurement of particle motion in spiral gas–solid two-phase flow

With a concise review on some basic and novel algorithms and methods for the techniques of particle-imaging velocimetry (PIV), the paper reports an application of the PIV techniques to the investigation of particle motion in a gas–solid two-phase spiral flow in a horizontal tube. Axial velocities of the transported particles are obtained. Some important features of particle motion governing high transportation efficiency of the spiral flow are revealed by investigating probability density distribution of particle locations in a pipe cross-section.