This study presents a novel approach to the design process of a permanent-magnet flux-modulated machine by simultaneously focusing on the machine major advantage and disadvantage, that is, the high torque density and low power factor. The machine can be designed with a high power factor while retaining the high torque density. To do so, they both need to be described precisely. The torque equation is improved by considering the stator-winding leakage flux. It determines the relation between the geometric parameters and the torque more accurately. The power-factor equation is derived from the electric equivalent circuit representing the simplest description of the machine. The machine geometry optimised with the design of experiments via Taguchi methods assures the best possible performance within the set limitations. It is shown that using the proposed design process makes the permanentmagnet flux-modulated machine more appropriate than the classical synchronous machine for the direct drive applications requiring a high torque density, low weight and high efficiency.

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Ti6Al4V titanium alloys are widely used in a variety of scientific and industrial fields. Laser beam welding is one of the most effective techniques for the joining of titanium plates. The main objective of this study was to investigate the influence of the most important laser parameters on welding performance of titanium alloy in two different physical environments such as air and water (i.e., serum) media. Specifically, the laser beam welding of 2 mm thick Ti6Al4V samples was applied using an Nd:YAG laser in open-air welding using argon as a shielding gas, and in wet welding using a serum environment. The deepest penetration was achieved at −3 mm focal position with 11 J of laser energy in both investigated media (i.e., air and serum). The maximum hardness (1130 HV) was achieved for the focal position of −4 mm in serum medium while it was 795 HV for a focal position of −5 mm in air medium. The minimum (1200 μm and 800 μm) and maximum (1960 μm and 1900 μm) weld widths were observed for air and serum medium, respectively. After the welding process, martensite, massif martensite, and transformed martensite were observed in the microstructure of Ti6Al4V. To the best of our knowledge, the underwater wet welding of titanium alloy was carried out and reported for the first time in this study.