Survey of highly non-Keplerian orbits with low-thrust propulsion

Celestial mechanics has traditionally been concerned with orbital motion under the action of a conservative gravitational potential. In particular, the inverse square gravitational force due to the potential of a uniform, spherical mass leads to a family of conic section orbits, as determined by Isaac Newton, who showed that Kepler‟s laws were derivable from his theory of gravitation. While orbital motion under the action of a conservative gravitational potential leads to an array of problems with often complex and interesting solutions, the addition of non-conservative forces offers new avenues of investigation. In particular, non-conservative forces lead to a rich diversity of problems associated with the existence, stability and control of families of highly non-Keplerian orbits generated by a gravitational potential and a non-conservative force. Highly non-Keplerian orbits can potentially have a broad range of practical applications across a number of different disciplines. This review aims to summarize the combined wealth of literature concerned with the dynamics, stability and control of highly non-Keplerian orbits for various low thrust propulsion devices, and to demonstrate some of these potential applications

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 cotton’s 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

Emissions Trading and the Polluter-Pays Principle : do Polluters Pay under Grandfathering?

Emissions trading is becoming increasingly popular in environmental law. Allowances to trade emissions can either be auctioned off or handed out free of charge by means of grandfathering. Although grandfathering is frequently used in emissions trading schemes, it is a popular view in the economic and legal literature that grandfathering is inconsistent with the polluter-pays principle. We come to a different, more nuanced view. The question of whether polluters pay under grandfathering depends on how the polluter-pays principle is interpreted. We present a taxonomy of interpretations. Based on an efficiency interpretation of the principle, consistency is demonstrated by emphasizing the economic impact of the opportunity costs of gratis allowances and the lump sum nature of the subsidy that is inherent to grandfathering. Inconsistency can only be claimed based on an equity interpretation of the polluter-pays principle. Allocating allowances free of charge means that polluting firms receive a capital gift making their shareholders richer, which may be perceived as unfair. We draw two conclusions. First, contrary to what some have claimed, grandfathering is compatible with an efficiency interpretation of the polluter-pays principle. Second, only auctioning is consistent with an extended form of this principle. Auctioning ensures not only that pollution costs are internalized (efficiency), but also that producers buy their allowances before they pass on those costs to consumers (equity)

Deutsche Gesellschaft fuer Luft- und Raumfahrt - Jahrbuch 1999. Bd. 1 Vortraege

Available from TIB Hannover: ZS 4076(1999,1) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman