Sleep spindles are waxing and waning thalamocortical oscillations with accepted frequencies of between 11 and 16 Hz and a minimum duration of 0.5 s. Our research has suggested that there is spindle activity in all of the sleep stages, and thus for the present analysis we examined the link between spindle activity (Stage 2, rapid eye movement (REM) and slow wave sleep (SWS)) and waking cognitive...

The purpose of this study was to investigate the effect of an uneven surface on muscle spindle function in lower-leg muscles during walking. Subjects included 3 healthy young adult males. Normal and high-speed walking motion ware measured on two surfaces: an even surface and an uneven surface. Healthy and reduced muscle spindle function conditions were compared. The ice immersion approach was a...

Variable speed main spindle drives of machine tools are usually fed by three-phase two-level inverters. Because of the switching operating mode of these inverters, the motor voltages and currents contain harmonics which do not contribute to torque formation but solely to an undesirable warming of motor spindle elements. This warming results in thermal elongation of the spindle shaft and therefo...

This paper presents theoritical and experimental design of a robust control based on quantitative feedback theory (QFT) approach to control deepness variations on cutting process for a spindle of lathe machine. The dynamics of a spindle is uncertain and varying due to deepness variation on cutting process. Practical design steps are explained in which QFT based conditions are assembled to obtai...

& Experiments and finite difference thermal modeling of the induction-heated tool for end milling of elastomers are investigated. Three sets of experiments are designed to calibrate the contact thermocouple for the tool tip temperature measurement, study the effect of tool rotational speed on induction heat generation and convective heat transfer, and measure the tool temperature distribution f...

First part of the thesis deals with the dynamics and stability of nonlinear delay gyroscopic systems with periodically varying delay. The aim is to demonstrate that greater depths of cut may be achieved in a boring process (2 DOF) when the speed of the spindle is modulated sinusoidally instead of being kept constant. Since the variation of spindle speed is small and independent of the tool moti...

Conventional drilling has been widely used for making holes in structural materials. However, drawbacks like high cutting forces, poor surface finish, temperatures, excessive tool wear, and undesirable burr formation while magnesium alloys have necessitated the development of alternative hole-making methods. Lately, helical milling process attracted interest facilitating assembly applications. ...

Controlling the process variations on the perimeter of a component to the targeted mean in milling is a huge challenge. Several factors such as spindle speed, feed rate, depth of cut, etc. affects this process variation. In this paper, spindle speed and feed rate are considered. Aluminum alloy 6061 widely used materials in aircraft, automobile and helicopter components is selected for this stud...