Running characteristics of aerodynamic bearing with self-lifting capability at low rotational speed

This article has been made available through the Brunel Open Access Publishing Fund - Copyright @ 2011 Tadeusz Adam Stolarski.An aerodynamic journal bearing that is capable of self-generating squeeze-film pressure is presented and its dynamic characteristics investigated numerically and experimentally. A numerical method based on a time-marching static model was applied to assess the orbit trajectory path of the rotor upon a perturbation. Experimental results were obtained to validate the effect of the self-generated squeeze-film pressure on the stability of the rotor. Analyzing the Fast Fourier Transform (FFT) responses of the rotor orbits enabled identification of self-excited whirling instabilities. Both numerical and experimental results showed that increasing the squeeze-film effect of the bearing could raise the threshold speed of instability

Short seed extractors against quantum storage

Some, but not all, extractors resist adversaries with limited quantum storage. In this paper we show that Trevisan's extractor has this property, thereby showing an extractor against quantum storage with logarithmic seed length

Top-Antitop cross section measurement in the di-lepton decay channel with ATLAS

We present simulations of the production cross-section measurement of top-antitop pairs in the di-leptonic decay channel with the ATLAS detector. This study uses the Commissioning Service Challenge (CSC) data, which is the latest and centrally produced Monte-Carlo data set to validate the detector simulation before the actual data taking. The signal process was generated with MC@NLO and important background processes were studied. A cut and count method and two likelihood methods were employed to measure the cross section and important systematic effects were investigated. The expected statistical and systematic errors for a luminosity of 100 \ipb are also given.Comment: 3 page