Synthesis and characterization of PEFC membranes based on fluorinated-polymer-alloy using pre-soft-EB grafting method

Polymer electrolyte fuel cell (PEFC) membranes based on thin film of crosslinked perfluorinated polymer-alloys (RX-FA) have been fabricated by soft electron beam (soft-EB) grafting with styrene monomers using soft-EB irradiation under nitrogen atmosphere at room temperature (RT). The characteristic properties of styrene-grafted materials (GRX-FA) and sulfonated materials (SRX-FA) have been measured by differential scanning calorimetry (DSC) and FT-IR spectroscopy, ionic conductivity and so on. The glass transition temperatures (dry state) of all obtained SRX-FA were about 105 ± 1 °C, which are higher than Nafion^®. The ion exchange capacities of SRX-FA have been achieved about 3.3 meq/g (dry). The ionic conductivity of obtained SRX-FA has showed about 0.17 S/cm at 60 °C with relative humidity (RH) of ∼95%. The ionic conductivities of the obtained SRX-FA were higher than that of conventional perfluoro-sulfonic acid membranes (PFSA). Fabricated membrane electrode assemblies (MEAs) based on the obtained SRX-FA have shown encouraging performance in the PEFC, compared with the conventional PFSA. The power density of obtained MEAs based on the SRX-FA was about 330-340 mW/cm² under 500 mA/cm² at 60 °C operation. Moreover, the maximum power densities of obtained MEAs based on the SRX-FA shows about 630 mW/cm² at 60 °C. On the other hand, the power density at 500 mA/cm² and maximum power density of MEA based on Nafion^®112 were about 320 and 590 mW/cm² at 60 °C. Thus, the power density of the obtained SRX-FA was higher than that of conventional PFSA.     

Multi-driver agent-based traffic simulation systems for evaluating the effects of advanced driver assistance systems on road traffic accidents

A recent investigation revealed that there is a substantiated need for the development of a micro-simulation system designed for traffic safety assessment. This paper describes the development of a road traffic simulation system, which uses a ‘nanoscopic model’ of driver behaviour and an integrated analysis-evaluation system designed for traffic safety assessment. The primary focus is on estimating the effects of an advanced driver assistance system thereby reducing traffic accidents. The effectiveness and validity of the present system are demonstrated through comparison with measured traffic data. This paper also proposes algorithms embedded in a ‘driver-agent’, for recognising driver’s intentions regarding choosing steering-control modes, lateral control tasks, and the driving mood. This is because the driver assistance systems need to recognise the driver’s intention when choosing steering-control. The results of a simulation study, using the data drawn from actual driving, show that the systems would achieve a high recognition capability. As an example of how driving mood recognition applies to driver assistance systems, an advanced steering system and the adaptability to the driver’s mood, have also been presented.     

Nanostructured TiO2 and Its Application in Lithium‐Ion Storage

Titania nanorods and nanowires are synthesized via a hydrothermal reaction of amorphous TiO₂ in alkaline NaOH, followed by ion exchange in HCl aqueous solution, and dehydration at 400 °C. Although the hydrothermal treatment produces three different particle morphologies depending on the reaction time (nanosheets, nanorods, and nanowires), the products exhibit the same crystal structure. Ion exchange of Na₂Ti₃O₇ in HCl aqueous solution brings about a phase change to H₂Ti₃O₇, but there is no change in the particle morphology. Dehydration of the nanostructured H₂Ti₃O₇ leads to two types of crystal structure—anatase TiO₂ for the nanorods, and TiO₂–B for the nanowires—although no significant difference is found in the morphology of the products even after dehydration. The nanorods are 40–50 nm in length and 10 nm in diameter, whereas the nanowires are several micrometers in length and tens to hundreds of nanometers in thickness. In‐situ X‐ray diffraction revealed the formation of anatase TiO₂ from the TiO₂–B above 450 °C. This finding implies that the phase transformation occurs rather slowly for the TiO₂–B nanowires due to the larger particle size and higher crystallinity of H₂Ti₃O₇. Tests with Li‐metal half cells indicated that the anatase TiO₂ nanorods are more favorable for the storage and release of Li ions because of their greater surface area than the TiO₂–B nanowires.     

Microwave Effect for Glycosylation Promoted by Solid Super Acid in Supercritical Carbon Dioxide

The effects of microwave irradiation (2.45 GHz, 200 W) on glycosylation promoted by a solid super acid in supercritical carbon dioxide was investigated with particular attention paid to the structure of the acceptor substrate. Because of the symmetrical structure and high diffusive property of supercritical carbon dioxide, microwave irradiation did not alter the temperature of the reaction solution, but enhanced reaction yield when aliphatic acceptors are employed. Interestingly, the use of a phenolic acceptor under the same reaction conditions did not show these promoting effects due to microwave irradiation. In the case of aliphatic diol acceptors, the yield seemed to be dependent on the symmetrical properties of the acceptors. The results suggest that microwave irradiation do not affect the reactivity of the donor nor promoter independently. We conclude that the effect of acceptor structure on glycosylation yield is due to electric delocalization of hydroxyl group and dielectrically symmetric structure of whole molecule.     

Space charge formation and breakdown in polyethylene influenced by the interface with semiconducting electrodes

This paper deals with the influence of interface between polyethylene and semiconducting electrode on the space charge formation and electrical breakdown. Low‐density polyethylene (LDPE) films attached with different semiconducting electrodes were subjected to the DC breakdown test, and corresponding space charge distribution was measured. A heat treatment to LDPE itself did not bring about a significant change in space charge profile; however, when a semiconducting electrode was hot‐pressed, the impurities would migrate into LDPE at high temperature, leading to the change in space charge profile. Furthermore, it was suggested from the comparison between the results with degassed and as‐received semiconducting electrodes that some carriers relating to impurities in the electrode would move into LDPE under the voltage. In addition, it was shown that the breakdown is not determined by the field at the cathode which can supply sufficient electrons, but by the maximum field across the specimen, suggesting that an increase in conduction current due to the generation and/or injection, rather than the electronic avalanche process, leads to the breakdown. © 2001 Scripta Technica, Electr Eng Jpn, 138(3): 19–25, 2002     

Collaboration work for nuclear power building using 3D CAD information

In the construction work for the Unit No.5 Turbine Building at Hamaoka Nuclear Power Station, the collaboration work for the planning and the coordination of the building construction and the machinery installation was carried out utilizing three-dimensional computer aided design (3D CAD) information. It was the first time in Japan for a building constructor and a plant manufacturer to work together, exchanging 3D CAD data of the whole building and adjusting the construction schedule. It was made possible to confirm the correspondence concerning the planning of both companies from the primary stage of the project by the total process simulation and to adjust on-going work precisely by the partial process simulation.     

Effect of an additive on the radiation resistance of polyethylene and ethylene–propylene copolymer

In low-density polyethylene containing the additive propylfluorancene, radiation energy received by polyethylene is transferred to propylfluorancence, and the production of radicals at 77 K in polyethylene is suppressed. Propylfluoranncene also increases the rate of the decay of radicals of polyethylene at room temperature. The depression of radical production and accelaration of radical decay at room temperature results in the depression of gas production and crosslinks at room temperature in low-density polyethylene containing propylfluorancene. Similar results were obtained in ethylen–propylene copolymer containing the same additive.     

Aquatic toxicity and biodegradability of advanced cationic surfactant APA-22 compatible with the aquatic environment

Cationic surfactant is a chemical substance used in hair conditioner, fabric softener and other household products. By investigating the relationship between the aquatic toxicity and the chemical structures of two types of mono alkyl cationic surfactants, alkyl trimethylammonium salts and alkyl dimethylamine salts, we have found that the C22 alkyl chain length is effective to reduce the toxicity. Besides, we have recognized that the amidopropyl functional group contributes to the enhanced biodegradability by investigating the biodegradation trend of (alkylamidopropyl)dimethylamine salt (alkyl chain length: C18). Based on these findings, we have developed mono alkyl cationic surfactant called APA-22, N-[3-(dimethylamino)propyl]docosanamide salt. APA-22 is formed by the C22 alkyl chain, amidopropyl functional group and di-methyltertiary amine group. We evaluated the aerobic and anaerobic biodegradability of APA-22 by two standard methods (OECD Test Guideline 301B and ECETOC technical document No.28) and found that this substance was degraded rapidly in both conditions. The toxicity to algae, invertebrate and fish of this substance are evaluated by using OECD Test Guideline 201, 202 and 203, respectively. All acute toxicity values are >1 mg/L, which indicates that environmental toxicity of this substance is relatively less toxic to aquatic organism. In addition, we estimated the biodegradation pathway of APA-22 and observed the complete disappearance of APA-22 and its intermediates during the test periods. Based on the environmental data provided above, we concluded that APA22 is more compatible with the aquatic environment compared to other cationic surfactants with mono long alkyl chain.