30 research outputs found
Modeling the Seasonal Variability of the Plasma Environment in Saturn's Magnetosphere between Main Rings and Mimas
The detection of O2+ and O+ ions over Saturn's main rings by the Cassini INMS
and CAPS instruments at Saturn orbit insertion (SOI) in 2004 confirmed the
existence of the ring atmosphere and ionosphere. The source mechanism was
suggested to be primarily photolytic decomposition of water ice producing
neutral O2 and H2 (Johnson et al., 2006). Therefore, we predicted that there
would be seasonal variations in the ring atmosphere and ionosphere due to the
orientation of the ring plane to the sun (Tseng et al., 2010). The atoms and
molecules scattered out of the ring atmosphere by ion-molecule collisions are
an important source for the inner magnetosphere (Johnson et al., 2006; Martens
et al. 2008; Tseng et al., 2010 and 2011). This source competes with water
products from the Enceladus' plumes, which, although possibly variable, do not
appear to have a seasonal variability (Smith et al., 2010). Recently, we found
that the plasma density, composition and temperature in the region from 2.5 to
3.5 RS exhibited significant seasonal variation between 2004 and 2010 (Elrod et
al., 2011). Here we present a one-box ion chemistry model to explain the
complex and highly variable plasma environment observed by the CAPS instrument
on Cassini. We combine the water products from Enceladus with the molecules
scattered from a corrected ring atmosphere, in order to describe the temporal
changes in ion densities, composition and temperature detected by CAPS. We
found that the observed temporal variations are primarily seasonal, due to the
predicted seasonal variation in the ring atmosphere, and are consistent with a
compressed magnetosphere at SOI.Comment: This is submitted to P&S
Cotton in the new millennium: advances, economics, perceptions and problems
Cotton is the most significant natural fibre and has been a preferred choice of the textile industry and consumers since the industrial revolution began. The share of man-made fibres, both regenerated and synthetic fibres, has grown considerably in recent times but cotton production has also been on the rise and accounts for about half of the fibres used for apparel and textile goods. To cottonâs advantage, the premium attached to the presence of cotton fibre and the general positive consumer perception is well established, however, compared to commodity man-made fibres and high performance fibres, cotton has limitations in terms of its mechanical properties but can help to overcome moisture management issues that arise with performance apparel during active wear.
This issue of Textile Progress aims to:
i. Report on advances in cotton cultivation and processing as well as improvements to conventional cotton cultivation and ginning. The processing of cotton in the textile industry from fibre to finished fabric, cotton and its blends, and their applications in technical textiles are also covered.
ii. Explore the economic impact of cotton in different parts of the world including an overview of global cotton trade.
iii. Examine the environmental perception of cotton fibre and efforts in organic and genetically-modified (GM) cotton production. The topic of naturally-coloured cotton, post-consumer waste is covered and the environmental impacts of cotton cultivation and processing are discussed. Hazardous effects of cultivation, such as the extensive use of pesticides, insecticides and irrigation with fresh water, and consequences of the use of GM cotton and cotton fibres in general on the climate are summarised and the effects of cotton processing on workers are addressed. The potential hazards during cotton cultivation, processing and use are also included.
iv. Examine how the properties of cotton textiles can be enhanced, for example, by improving wrinkle recovery and reducing the flammability of cotton fibre