An interface consisting of an antiphase boundary (APB) and a short-range-ordering interphase layer (ϳ4 nm) in the elongated ␥Ј precipitate for a chosen model alloy was examined. Interface image simulations, high-resolution electron microscopy (HREM), and scanning transmission electron microscopy (STEM) techniques were employed to show interfacial segregation at an APB and to identify the local composition changes across it. Emphasis is also given to understanding the influence of the APB on the microstructural evolution in the rafting mechanism. In contrast to the widely accepted notion that out-of-phase precipitates never coalesce to form a single particle, results of this study indicate that complete coalescence of ␥Ј precipitates during annealing may occur at high temperatures as a result of the glide and climb of a 1/2 Ͻ110Ͼ superpartial dislocation in the thin interphase layer, despite the presence of an APB between the merging ␥Ј particles.

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Low cycle fatigue (LCF) tests were conducted on SA533 steels with different levels of sulphur content at room temperature and 300°C. The fatigue limit shows little or no dependence on sulphur content, but signi cantly depends on testing temperature. At 300°C, the fatigue limit is at 0 . 2% strain amplitude, slightly higher than the 0 . 1% strain amplitude obtained at room temperature. The fatigue limit of SA533 steel subjected to LCF tests at 300°C was improved by the combined effects of dynamic strain aging (DSA) and grain size reduction. DSA and grain size reduction increase the steel strength and, accordingly, improve the LCF limit at 300°C. But, concurrently, the carbide/nitride precipitates in SA533 steel lead to a decrease in steel strength. Grain size reduction and precipitation compete with each other. Grain size reduction is dominant and the net effect is re ected in the increase in hardness value. Fatigue life could be predicted either by means of the strain -life equation or the SWT (Smith, Watson and Topper) parameter for specimens under low cycle fatigue conditions. The strain -life equation for SA533 steel in air is independent of the sulphur content, but signi cantly dependent on the testing temperature.

The application of methanol sensor‐less control in a direct methanol fuel cell (DMFC) system eliminates most of the problems encountered when using a methanol sensor and is one of the major solutions currently used in commercial DMFCs. This study focuses on analyzing the effect of the operating characteristics of a DMFC system on its performance under the methanol sensor‐less control as developed by Institute of Nuclear Energy Research (INER). Notably, the influence of the dispersion of the methanol injected on the behavior of the system is investigated systematically. In addition, the mechanism of the methanol sensor‐less control is investigated by varying factors such as the timing of the injection of methanol, the cathode flow rate, and the anode inlet temperature. These results not only provide insight into the mechanism of methanol sensor‐less control but can also aid in the improvement and application of DMFC systems in portable and low‐power transportation.

When defects are imaged using weak beam techniques it is common to use a higher beam convergence than when they are imaged under strong two beam conditions because of the way specimen drift limits the exposure times that can be used. It is demonstrated that, for a typical illumination system, as the convergence is increased the range of tilt across the probed area is also increased. This can affect the weak beam imaging behaviour of a defect, and the α‐fringe contrast of thin twins is examined in this context. The contrast changes in the field of view associated with the local variation in tilt are discussed in relation to the degree to which the relative effects of convergence on α‐fringe and thickness fringe contrast can be qualitatively understood kinematically. However, some effects, such as the observed increase in α‐fringe contrast at moderate convergence, are more difficult to model but are also potentially of greater concern in the characterization of the differences in contrast to be expected for intrinsic and extrinsic faults as well as for twins.