Flow-induced vibration of a head gimbal assembly under various conditions
The flow-induced vibration of a head gimbal assembly (HGA), known as windage, is an obstacle to achieving higher track densities in hard disk drives (HDDs). We examine the characteristics of windage in this paper with the goal of enabling the development of smaller-windage HGAs. We used a 14.5-mm-length (from swage hole center to dimple) HGA in our study. The windage was measured by a laser Doppler vibrometer in a spin stand under various conditions, such as different slider radius locations (inner diameter, medium diameter, and outer diameter), disk-rotational speeds, Z heights (distance from arm to disk), and temperatures. With respect to the slider radius location, windage was much greater when the slider was on the outer diameter rather than at other positions. When the slider was positioned at a fixed location, the windage was proportional to the square of the disk rotational speed. At high temperatures, the resonant frequencies decreased and their amplitudes increased. For some resonance modes, there was an optimal Z height. These findings will be useful for evaluating HGAs and optimizing HGAs through experimental design.
Flow-induced vibration measurement system for Head Gimbal Assembly
The flow-induced vibration of a head gimbal assembly, known as “windage", is a very large obstacle for achieving the higher track densities in hard disk drives. We developed a windage measurement system that can measure windage by a laser Doppler vibrometer in a spin stand at various conditions, such as different disk-rotational speeds, temperatures, and so on. Therefore, the developed system is useful for investigating the nature of windage and to design new head gimbal assembly to reduce windage.
Ideological Quietism? Ideology and Party Politics in Britain
Ideology and political parties are frequently depicted as disparate entities, with scholars citing a range of exogenous and endogenous changes to demonstrate the decreasing relevance of ideology to party politics. This article moves away from such accounts by looking at the role of actors, and specifically party leaders, in contributing to perceptions of ideological decline. Through an examination of the rhetoric of Labour and Conservative Party leaders in Britain between 1946 and 1997, this article contends that politicians have engaged in, what is termed here, ‘ideological quietism’. In this sense, parties have not abandoned ideology but have made rhetorical shifts indicative of ideological decline.