Optical enhancement of photomultiplier sensitivity

Transmission and reflection light losses are reduced by introducing light into end-window of device at an angle large enough to normal so total internal reflection occurs at both photocathode-vacuum and window-air interfaces

Quasi-Normal Modes of Brane-Localised Standard Model Fields

We present here a detailed study of the quasi-normal spectrum of brane-localised Standard Model fields in the vicinity of D-dimensional black-holes. A variety of such backgrounds (Schwarzschild, Reissner-Nordstrom and Schwarzszchild-(Anti) de Sitter) are investigated. The dependence of the quasi-normal spectra on the dimensionality D, spin of the field s, and multipole number l is analyzed. Analytical formulae are obtained for a number of limiting cases: in the limit of large multipole number for Schwarzschild, Schwarzschild-de Sitter and Reissner-Nordstrom black holes, in the extremal limit of the Schwarzschild-de Sitter black hole, and in the limit of small horizon radius in the case of Schwarzschild-Anti de Sitter black holes. We show that an increase in the number of hidden, extra dimensions results in the faster damping of all fields living on the brane, and that the localization of fields on a brane affects the QN spectrum in a number of additional ways, both direct and indirect.Comment: 13 pages, 4 figures, to be published in Phys. Rev.

The effect of support flexibility and damping on the dynamic response of a single mass flexible rotor in elastic bearings

The dynamic unabalance response and transient motion of the single mass Jeffcott rotor in elastic bearings mounted on damped, flexible supports are discussed. A steady state analysis of the shaft and the bearing housing motion was made by assuming synchronous precession of the system. The conditions under which the support system would act as a dynamic vibration absorber at the rotor critical speed were studied. Plots of the rotor and support amplitudes, phase angles, and forces transmitted were evaluated by the computer and the performance curves were plotted by an automatic plotter unit. Curves are presented on the optimization of the support housing characteristics of attenuate the rotor synchronous unbalance response

Transient journal bearing analysis

Transient response of fluid film journal bearin

Optical enhancement of sensitivity in laser Doppler velocity systems

Utilization of optical enhancement techniques prevents loss of light by reflections at the photocathode of a photomultiplier and increases signal detection sensitivity

Laser velocimeter for simultaneous two-dimensional velocity measurements

Laser velocimeter provides simultaneous orthogonal measurements in manner which minimizes many problems attending prior systems, and allows spatial traversing of flowfield in order to obtain velocity profiles. Velocimeter permits rapid interrogation of unsteady flows where area of interest is of the order of one meter in extent and flow does not vary appreciably over time of about one second

Nondispersive infrared analyzer for specific gases in complex mixtures

Analyzer identifies and measures particular diatomic or polyatomic gases in complex gas mixtures. Mixing of absorption effects on light energy passing through gases to photodetector produces a signal component that is related to the absorption caused by reference-gas component in unknown gas mixture

Performance improvement in pharmaceutical R&D through new outsourcing models

The stimulation of innovation in the pharmaceutical industry through outsourcing of research and development (R&D) activities within the drug discovery and development process is analysed. The empirical data were collected through interviews with experts of pharmaceutical companies and service providers between 2002 and 2005. Additionally, in 2008, the outsourcing behaviour of the already interviewed and additional companies was analysed through desk research. The results show that the outsourcing behaviour of traditional and emerging pharmaceutical companies is completely different. Whereas the make-or-buy decisions of traditional companies are mainly competency or know-how driven, that of emerging companies are primarily capacity or cost driven. Nevertheless, for both types of companies the cooperation model of “strategic partnership” offers access to high-level expertise while reducing fixed costs and complexity. Within this model, external providers are temporarily integrated into internal R&D teams and thus able to support R&D projects flexibly and more timely

Asymmetric polarity reversals, bimodal field distribution, and coherence resonance in a spherically symmetric mean-field dynamo model

Using a mean-field dynamo model with a spherically symmetric helical turbulence parameter alpha which is dynamically quenched and disturbed by additional noise, the basic features of geomagnetic polarity reversals are shown to be generic consequences of the dynamo action in the vicinity of exceptional points of the spectrum. This simple paradigmatic model yields long periods of constant polarity which are interrupted by self-accelerating field decays leading to asymmetric polarity reversals. It shows the recently discovered bimodal field distribution, and it gives a natural explanation of the correlation between polarity persistence time and field strength. In addition, we find typical features of coherence resonance in the dependence of the persistence time on the noise.Comment: 5 pages, 7 figure

Network Infrastructure Configuration

The nine papers in this special issue focus on network infrastructure configuration and some of the problems encountered in the areas of specification, diagnosis, repair, synthesis, and anonymization