Method for measuring the characteristics of a gas Patent

Device for simultaneously determining density, velocity, and temperature of streaming ga

Electrostatic plasma modulator for space vehicle re-entry communication Patent

Electrostatic modulator for communicating through plasma sheath formed around spacecraft during reentr

Price flexibility in British supermarkets

This paper delivers a significantly different empirical perspective on micro pricing behaviour and its impact on macroeconomic processes than previous studies. We examine a seven year period of pricing behaviour by the major British supermarkets encompassing the recession year 2008 and the partial recovery of 2009. Several of our findings run strongly counter to established empirical regularities, in particular the high overall frequency of regular or reference price changes we uncover, the greater intensity of change in more turbulent times and the numerical dominance of price falls over rises. The pricing behaviour revealed also significantly challenges the implicit assumption that prices are tracking cost changes

Identifying and characterising price leadership in British supermarkets

Price leadership is a concept that lacks precision. We propose a deliberately narrow, falsifiable, definition and illustrate its feasibility using the two leading British supermarket chains. We find both firms engaging in leadership behaviour over a range of products, with the larger being somewhat more dominant but the smaller increasing leadership activity over time. Surprisingly, more price leadership events are price reductions than price increases, but the increases are of larger monetary amounts (so average price increases over time) and the events appear not necessarily related to cost changes. Price leadership appears to play some role in price increases

Modeling and removal of optical ghosts in the PROBA-3/ASPIICS externally occulted solar coronagraph

Context: ASPIICS is a novel externally occulted solar coronagraph, which will be launched onboard the PROBA-3 mission of the European Space Agency. The external occulter will be placed on the first satellite approximately 150 m ahead of the second satellite that will carry an optical instrument. During 6 hours per orbit, the satellites will fly in a precise formation, constituting a giant externally occulted coronagraph. Large distance between the external occulter and the primary objective will allow observations of the white-light solar corona starting from extremely low heights 1.1RSun. Aims: To analyze influence of optical ghost images formed inside the telescope and develop an algorithm for their removal. Methods: We implement the optical layout of ASPIICS in Zemax and study the ghost behaviour in sequential and non-sequential regimes. We identify sources of the ghost contributions and analyze their geometrical behaviour. Finally we develop a mathematical model and software to calculate ghost images for any given input image. Results: We show that ghost light can be important in the outer part of the field of view, where the coronal signal is weak, since the energy of bright inner corona is redistributed to the outer corona. However the model allows to remove the ghost contribution. Due to a large distance between the external occulter and the primary objective, the primary objective does not produce a significant ghost. The use of the Lyot spot in ASPIICS is not necessary.Comment: 14 pages, 13 figure

OPserver: interactive online-computations of opacities and radiative accelerations

Codes to compute mean opacities and radiative accelerations for arbitrary chemical mixtures using the Opacity Project recently revised data have been restructured in a client--server architecture and transcribed as a subroutine library. This implementation increases efficiency in stellar modelling where element stratification due to diffusion processes is depth dependent, and thus requires repeated fast opacity reestimates. Three user modes are provided to fit different computing environments, namely a web browser, a local workstation and a distributed grid.Comment: 5 pages, 1 figur