Applications study of advanced power generation systems utilizing coal-derived fuels. Volume 1: Executive summary

The technology status of phosphoric acid and molten carbon fuel cells, combined gas and steam turbine cycles, and magnetohydrodynamic energy conversion systems was assessed and the power performance of these systems when operating with medium-Btu fuel gas whether delivered by pipeline to the power plant or in an integrated mode in which the coal gasification process and power system are closely coupled as an overall power plant was evaluated. Commercially available combined-cycle gas turbine systems can reach projected required performance levels for advanced systems using currently available technology. The phosphoric acid fuel cell appears to be the next most likely candidate for commercialization. On pipeline delivery, the systems efficiency ranges from 40.9% for the phosphoric acid fuel cell to 63% for the molten carbonate fuel cell system. The efficiencies of the integrated power plants vary from approximately 39-40% for the combined cycle to 46-47% for the molden carbonate fuel cell systems. Conventional coal-fired steam stations with flue-gas desulfurization have only 33-35% efficiency

Rural young people's opportunities for employment and entrepreneurship in globalised southern Africa: The limitations of targeting policies

This paper is based on a study with rural young people in Malawi and Lesotho, focusing on their possibilities for accessing (self)employment in the face of the various constraints imposed by their poor rural situations. Participatory group exercises, combined with individual interviews in two rural villages, provided personal stories about jobs and businesses that the young people were engaged in, as well as previous experiences and future plans. Constraints, as well as enabling factors, working at both individual and structural levels were analysed. Policies intended to address the needs of young people tend to seek to target the most vulnerable, often on the basis of individual-and household-level characteristics (e.g. women, orphans and AIDS-affected households). We argue that this: (1) neglects the structural factors operating at national and global levels; and (2) fails to recognise that factors interact to produce vulnerability, rather than this being rooted in separate characteristics. We demonstrate that an intersectional approach, drawn from feminist studies, is a useful theoretical lens, which, in combination with a livelihoods perspective, helps illuminate the needs of rural young people. In situations characterised by high levels of poverty and multiple vulnerabilities, we argue that it can be costly and ineffective to try to decide 'who is most vulnerable'; rather, resources can be more effectively spent in trying to improve conditions that will benefit all rural young people

Reply to ``Comment on ``Lateral Casimir Force beyond the Proximity Force Approximation'' ''

We reply to the comment arXiv:quant-ph/0702060 on our letter arXiv:quant-ph/0603120 [Phys. Rev. Lett. 96, 100402 (2006)]Comment: 1 pag

The spatial construction of young people's livelihoods in rural southern Africa

Young people in southern Africa, in common with young people around the world, are social agents, constructing their own lives, albeit within significant structural constraints. Unlike young people in some regions, for most the need to generate a livelihood is a key consideration. Livelihood construction is a profoundly spatial activity, yet while there have been a number of studies of the spatial construction of young people's livelihoods in African cities, the spatiality of rural livelihoods has received less attention. Rural environments pose particular challenges for livelihood construction, and require particular spatial strategies. Four are discussed here: accessing education and training; migration for work; developing extensive social networks; and producing for markets. There are, however, aspects of the spatial structuring of rural southern African societies that seriously constrain the pursuit of productive livelihoods by young people. Two are considered: migration (for reasons unconnected with young people's livelihoods) and marriage practices

Electrometer system measures nanoamps at high voltage

Floating electrometer eliminates major source of error since any leakage from electrometer case, which is at high voltage, appears only as load on high voltage supply and not as part of current being measured. Commands to and data from floating electrometer are transferred across high voltage interface by means of optical channels

SCUBA - A submillimetre camera operating on the James Clerk Maxwell Telescope

The Submillimetre Common-User Bolometer Array (SCUBA) is one of a new generation of cameras designed to operate in the submillimetre waveband. The instrument has a wide wavelength range covering all the atmospheric transmission windows between 300 and 2000 microns. In the heart of the instrument are two arrays of bolometers optimised for the short (350/450 microns) and long (750/850 microns) wavelength ends of the submillimetre spectrum. The two arrays can be used simultaneously, giving a unique dual-wavelength capability, and have a 2.3 arc-minute field of view on the sky. Background-limited performance is achieved by cooling the arrays to below 100 mK. SCUBA has now been in active service for over a year, and has already made substantial breakthroughs in many areas of astronomy. In this paper we present an overview of the performance of SCUBA during the commissioning phase on the James Clerk Maxwell Telescope (JCMT).Comment: 14 pages, 13 figures (1 JPEG), Proc SPIE vol 335

Socio-economic causes of food insecurity in Malawi

The food crisis that Malawi experienced in 2002 led to hundreds – maybe thousands – of hunger-related deaths, which is more than any famine in living memory. During this famine, maize production fell by over 30% and maize prices rose by over 300% (Devereux, 2002). At the peak of the crisis, nearly a third of the population were dependent on food aid (USAID/Malawi, 2004)