Optimization of the Drive System Choice for a Class of Drilling Machines

In this paper are analyzed and formulated the basic requirements for the drive system of a class of modernized drilling machines. On this basis, a methodology for optimal choice of the feed and spindle drives is offered. The respective algorithm takes into account the specific features of the technological processes, the processed materials, the tools used and their wear, as well as the mechanical gear types. Examples with DC and AC motor drives for the coordinate axes and the spindle are presented, illustrating the practical application of the offered methodology. The research carried out and the results obtained can be used in the development of drive systems for the studied class of machine tools.

Rational Choice Meets the New Politics: Choosing the Scottish Parliament’s Electoral System

Although there has been extensive research on electoral system choice at the national level, we know relatively little about the dynamics of deciding the rules of the game for sub-state institutions. This article examines the factors that influenced the choice of a proportional electoral system for the new Scottish Parliament in 1999. Through the use of archival sources and interviews with key participants, we challenge the conventional rational choice explanation for the adoption of the mixed-member proportional (MMP) system. Although rational considerations on the part of the Labour Party were involved in the choice of MMP, our findings suggest that, as at the national level, theories of electoral system choice need to consider normative values as well.