No abstract

The simple method for evaluation of fracture toughness in Mg alloys was examined by AE. In this study, fracture toughness (K IAE ) in AZ31 (Mg 9Al 1Zn), AZ91 (Mg 9Al 1Zn), and LA141 (Mg 14Li 1Al) was investigated. Specimens (L S, T S) were machined from as rolled AZ31, LA141, and as cast AZ91. Four point bending tests were conducted according to ASTM E 399 with AE measurement, and the crack pass was observed by microscope during the testing. K IC was supposed to be the value of K I when the crack initiates from the tip of the pre crack. K IAE was defined as the value of K I when the RMS voltage of AE indicated the maximum value before ultimate load. The crack propagation was observed by microscope at the time of RMS peak. The values of K IAE were 12.4 15.0 (AZ31), 11.5 11.7 (AZ91), and 24.

We prepared SmBa2Cu3Oy (SmBCO) superconducting bulks by partial melting growth with a top seed. From the results, we found that the SmBCO bulks prepared by melting process showed good superconductivity, where the critical temperature Tc and the temperature transition width ΔT of the bulk were 94K and about 1K, respectively. The as-prepared bulks required annealing at 500°C for 24h to improve the superconductivity. However, the characteristics of the bulks may be improved by more detailed study, for example optimum preparation and annealing conditions.

No abstract

This paper proposes a gain scheduled flight controller design method satisfying various design requirements, including gain and phase margins. The problem to satisfy stability margin requirement can be converted to an Integral Quadratic Constraints (IQC) stability condition. This IQC condition can be considered as a kind of mixed sensitivity H∞ problem with complex constant weights. Linear Matrix Inequality (LMI) theory is used to solve the derived mixed sensitivity problem. The effectiveness of the proposed method is verified by designing a lateral-directional flight controller for the Automatic Landing Flight Experiment (ALFLEX).