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This paper reports on the international PHESAT95 campaign of observations of the Saturnian events coordinated by Bureau des longitudes. Thanks to CCD or photometric receptors, accurate astrometric data can be get from the observation of the eclipses by Saturn and mutual events of the Saturnian satellites. These events occur from 1994 to 1996 and we give our first results.
From 1992 to 1999, the satellites of Saturn are involved in several phenomena: eclipses or occultations by the planet, transits in front of Saturn, or transits of their umbra. These phenomena occur thanks to the geometrical circumstances in 1995 when the Earth and the Sun went through the plane of the Saturnian ring and consequently through the orbital planes of the main satellites. These circumstances are also favorable to the observation of mutual phenomena occurring when the satellites eclipse or occult each other. These mutual phenomena and the eclipses by Saturn are rare as they occur only every 15 years. But, they are very useful to get highly accurate astrometric observations and they allowed us to estimate some physical parameters. We have organized the PHESAT95 campaign to observe these phenomena and a special effort was made to observe as many events as possible. At the present time, the observations are still being collected from different teams and different countries; this paper shows the first results which have been obtained in several sites, and the first comparison with the theory of the motions.
Expose is a multi-user instrument for astrobiological and astrochemical experiments in space. Installed at the outer surface of the International Space Station, it enables investigators to study the impact of the open space environment on biological and biochemical test samples. Two Expose missions have been completed so far, designated as Expose-E (Rabbow et al. 2012) and Expose-R (Rabbow et al. this issue). One of the space-unique environmental factors offered by Expose is full-spectrum, ultraviolet (UV)-rich electromagnetic radiation from the Sun. This paper describes and analyses how on Expose-R, access of the test samples to Solar radiation degraded during space exposure in an unpredicted way. Several windows in front of the Sun-exposed test samples acquired a brown shade, resulting in a reduced transparency in visible light, UV and vacuum UV (VUV). Post-flight investigations revealed the discolouration to be caused by a homogenous film of cross-linked organic polymers at the inside of the windows. The chemical signature varied per sample carrier. No such films were found on windows from sealed, pressurized compartments, or on windows that had been kept out of the Sun. This suggests that volatile compounds originating from the interior of the Expose facility were cross-linked and photo-fixed by Solar irradiation at the rear side of the windows. The origin of the volatiles was not fully identified; most probably there was a variety of sources involved including the biological test samples, adhesives, plastics and printed circuit boards. The outer surface of the windows (pointing into space) was chemically impacted as well, with a probable effect on the transparency in VUV. The reported analysis of the window contamination on Expose-R is expected to help the interpretation of the scientific results and offers possibilities to mitigate this problem on future missions – in particular Expose-R2, the direct successor of Expose-R.
In the context of the preservation of the cultural heritage, it is important to understand the alteration mechanisms of the materials constituting historical monuments and architecture. Limestone especially is widely used in many French monuments exposed to an urban aggressive atmosphere affecting their durability. To better understand the alteration mechanisms, the first step is to characterize at different scales the stone material properties. In one hand, the pore network that drives the fluids transfer inside the materials was characterized. And on the other hand, the alteration layer formed on several decades aged materials was studied. Results on this fine-scale characterization are discussed.
The craft of manufacturing cotton was learnt by the British in India, but the East India Company's drive for profits caused the development of a cotton-spinning industry in Britain, which grew enormously when mechanical processes were introduced during the industrial revolution. Subsequent protectionist legislation which forbade the export of anything except raw cotton meant that India's supremacy in the industry was lost to Britain in the nineteenth century. This 1867 work, edited by P. R. Cola, who owned the Arkwright Cotton Mills in Bombay (Mumbai), argues for investment in up-to-date machinery, and provides a blueprint for developing a host of industries such as cotton and other textiles, jute, sugar, oil and iron, which would bring prosperity to India. Containing illustrations and statistical data, the book gives useful insights into the early development of many industries in India and in some of the other economies of the East.