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The mechanical properties of duplex stainless steel (DSS) are known to display embrittlement due to ageing effects. Knowledge of the micro behaviour of aged DSS is important for understanding the mechanisms of deformation and failure, but it has proved difficult to obtain due to the complex effects created by the duplex structure. Lattice strain measurements of DSS aged under various conditions of temperature and time have been performed in order to determine the strain behaviour of individual (hkl) planes in the α- and γ-phases using white synchrotron radiation X-rays at SPring-8. It was found that the lattice strain of α-Fe(200) depends strongly on the ageing conditions and that the lattice strain behaviour in the γ-phase is more stable than that in the α-phase. These results suggest that the changes in macro mechanical properties, including yield strength and ultimate strength, which are revealed by standard tensile tests, are solely due to ageing effects in the α-phase. The results further suggest that the lattice strain of α-Fe(200) can be used as an index to evaluate 475 °C ageing effects in DSS. [ABSTRACT FROM PUBLISHER]

For the purpose of evaluating the fatigue strength of the Japanese railway wheel, fatigue testing was done on the actual size wheel, using a new resonance-type fatigue-testing machine. Because the maximum stress under the horizontal and vertical loads occurs at the wheel plate, the fatigue strengths of the wheel plate were measured and the safety factors versus design load were evaluated. Two kinds of typical Japanese railway wheel were tested and the results showed that their safety factors were larger than 2.4. [ABSTRACT FROM AUTHOR]

We studied the effects of a newly synthesized anti-ischaemic agent, 4-[3-(4-benzylpiperidin-1-yl) propionyl]-7-methoxy-2, 3, 4, 5-tetrahydro-1, 4-benzothiazepine monohydrochloride (JTV-519) on the delayed rectifier potassium current (IK), using guinea-pig ventricular myocytes and whole-cell voltage-clamp techniques, under blockade of the L-type calcium current (ICa,L) by D600 (1 µM) or nitrendipine (5 µM). The IK in guinea-pig ventricular cells consists of two different components; the rapidly activating, E4031-sensitive component (IKr) and the slowly activating E4031-resistant component (IKs). Under steady-state conditions, JTV-519 (1 and 5 µM) did not change the amplitude of IKs remaining after blockade of IKr with 5 µM E4031. The effect of JTV-519 on IKr was assessed using short (50 ms) pulses which evoked a tail current that was sensitive to E4031 but not to chromanol 293B, a specific blocker of IKs. JTV-519 suppressed the IKr with a half-maximal inhibitory concentration of 1.2 µM. Selective inhibition of IKr by this agent was confirmed by using the "envelope of tails" test. These results suggest that the blockade of IKr may underlie the prolongation of action potential duration in ventricular muscle and QT-intervals alleged to occur in animal as well as human hearts. [ABSTRACT FROM AUTHOR]

Colloidal single crystals of silica spheres (103 nm in diameter) are formed in the presence of various kinds of salts 1 simple electrolytes, i.e., sodium chloride, calcium chloride and lanthanum chloride, 2 polyelectrolytes such as 3-6 type ionen polymer (polybrene), poly- N-ethylpyridinium bromide, a copolymer of N-benzyl pyridinium chloride and N-hexadecyl pyridinium bromide, and sodium polyethylene sulfonate, and 3 cationic and anionic detergents, hexadecyltrimethylammonium bromide and sodium dodecylsulfate. Shape and size of their single crystals, phase diagram, and the relationship between the two parameters among the critical concentration of melting, conductance and pH of the crystal-like suspensions have been studied. Colloidal single crystals of positively charged spheres have been formed in this study by the method of the charge reversal of spheres through the strong adsorption of cationic polyelectrolytes onto the anionic silica spheres. [ABSTRACT FROM AUTHOR]

Characteristics of continuous hydrogen production and fatty acid formation by an active hydrogen-producing anaerobic bacterium, Clostridium butyricum strain SC-E1, was examined under vacuum and non-vacuum culture systems. The continuous cultures were performed using 1040 ml anaerobic glass bottles containing 600 ml of medium including glucoseand polypeptone at a concentration of 0.5 or 1.0% as substrate, and were conducted at pH 6.7, hydraulic retention time (HRT) 8h, and 30 deg. C on a reciprocal shaker. The non-vacuum cultures at 16 days of incubation showed 2.0 to 2.3 mol-H2/mol-glucose and 1.4 to 2.0 mol-H2/mol-glucose of hydrogen productivity at 0.5 and1.0% of substrate concentration, respectively. The vacuum cultures conducted at 0.28 atm gave 1.8 to 2.3 mol-H2/mol-glucose and 1.3 to 2.2 mol-H2/mol-glucose of hydrogen productivity at 0.5 and 1.0% of substrate concentration, respectively. The fatty acid production from the vacuum cultures exhibited approximately the same yield of fatty acids as those of the non-vacuum cultures. It was concluded that the maximal hydrogen production potential by anaerobic bacteria is 1.3 to 2.2 mol-H2/mol-glucose, which is less than 50% of theoretical. In addition, the total hydrogen production rate by a two-stage bioreactor consisting of a 1-litre anaerobic fermenter (HRT 10h) and a 4-litre photobioreactor (HRT 36h) feeding at 2.4-litre of 1.0% glucose per day was estimated at 1.4 to 5.6 mol-H2/mol-glucose, which is 12 to 47% theoretical. [ABSTRACT FROM AUTHOR]