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Abstract:

Optical diagnostics of gas-phase pressure are relatively unusual. In this work we demonstrate a novel, rapid and robust method to use laser-induced grating scattering (LIGS) to derive this property in real time. Previous pressure measurements with LIGS have employed a signal fitting methodology but this is relatively time consuming and requires specialist understanding. In this paper, we directly measure a decay lifetime from a LIGS signal and then employ a calibration surface constructed using a physics-based model to convert this value to pressure. This methodology was applied to an optically-accessible single cylinder internal combustion engine, yielding an accuracy of better than 10 % at all tested conditions above atmospheric pressure. This new approach complements the existing strength of LIGS in precisely and accurately deriving temperature with a simple analysis method, by adding pressure information with a similarly simple method.

Abstract:

The first demonstration of laser action in ruby was made in 1960 by T. H. Maiman of Hughes Research Laboratories, USA. Many laboratories worldwide began the search for lasers using different materials, operating at different wavelengths. In the UK, academia, industry and the central laboratories took up the challenge from the earliest days to develop these systems for a broad range of applications. This historical review looks at the contribution the UK has made to the advancement of the technology, the development of systems and components and their exploitation over the last 60 years.

Abstract:

Paul Ewart says it is unfair to force active physicists to retire to "free up" positions for younger scientists or to improve diversity – when there is little evidence that it does so