Running performance of an aerodynamic journal bearing with squeeze film effect

Results of theoretical and experimental studies concerning the performance of an aerodynamic journal bearing which running is assisted by squeeze film ultrasonic levitation (SFUL) are presented in this paper. The SFUL mechanism not only can separate journal from the bearing at the start and stop phases of operation but also can significantly contribute to the dynamic stability of the bearing when it runs at speed. Computer calculations and validating experimental testing of a prototype device were carried out. It was found that that SFUL mechanism, when combined with aerodynamic lift, extends the threshold speed of bearing’s instability by almost four times comparing to that of a bearing operating without SFUL. Typically, the bearing running without SFUL became unstable at the speed of 300 rpm while with the SFUL the speed at which instability became apparent was 10,000 rpm (calculated result) or 13,200 (experimental result)

Prototype Design and Feasibility Analysis for Self-Levitated Conveying

In order to avoid friction and scratching when conveying object, an acoustic levitation prototype was designed to verify the feasibility. The modal shapes and the forced harmonic shapes of the prototype are obtained by an ANSYS coupled field computation with a one-quarter symmetry model and the levitation capacity was assessed by the use of groups of simulation and physical testing. The simulation results showed that the pure flexural and mixed flexural wave shapes with different wave numbers existed at some specific frequency. The amplitude in the central point of an aluminum plate having four piezo-electric discs glued to the bottom surface was simulated for a frequency spectrum. The experimental results confirmed the theoretical results and the feasibility of the prototype and confirm that objects can be floated at several resonant frequencies under forced vibrating condition. The system can provide largest bearing capacity when both the piezoelectric disc and the plate resonances coincide

Friars on the frontier: Catholic renewal and the Dominican order in Southeastern Poland 1594-1648

This thesis analyses the role of the Dominican Order in the Catholicisation of southeastern Poland between 1594 and 1648. Until now, historians of Catholic renewal and the CounterReformation in Poland have focused predominantly on the impact of the Jesuits in isolation, paying little attention to the role of continuity across the Medieval, Renaissance and Baroque periods. This study of the Dominicans exemplifies the role of continuity within Catholicism in the post-Tridentine period, and serves as an analytical corrective to the hitherto dominant Jesuit-centred paradigm of the Counter-Reformation.EThOS - Electronic Theses Online ServiceGBUnited Kingdo