Advanced Solar Receivers

Low thermal efficiencies in solar receivers are discussed in terms of system design. It is recommended that careful attention be given to the overall thermal systems design, especially to conductive losses about the window and areas of relatively thin insulation. If the cavity design is carefully managed to insure a small, minimally reradiating aperture, the goal of a very high efficiency cavity receiver is a realistic one

Using Degree-Day Methodology to Ascertain Early Flight Periods of Michigan Butterflies and Skippers

Butterflies and skippers have been collected in Michigan for over 130 years and the accompanying data labels continue to provide significant information. Both collection date and site information for voucher specimens provide the data that is used to ascertain the daily maximum-minimum temperatures for the year in which the specimens were collected. This information may then be used to calculate the degree-day accumulations above a base value over those specific dates. The Michigan Entomological Society - Michigan Lepidoptera Survey (MLS) is a team of lepidopterists who have endeavored to create a composite database of all voucher specimens in museum and private collections, published data, and submitted data, as well as from surveys conducted throughout the state. This composite data set was used to formulate a first generation of early flight periods of Michigan butterflies and skippers. Accumulated degree-days for predicting the emergence/dispersal and thus the first early flight period are presented for Michigan butterfly and skipper species and subspecies

Concentrator Development

During the years of technology development by the Parabolic Dish program, the problems peculiar to tracking dishes have been explored in depth with particular emphasis on economics. Starting with the Precursor Concentrator, testing techniques and apparatus such as calorimeters and the flux mapper were developed. At the same time, mirrors were developed to have a long operating life as well as high performance. Commercially available equipment was evaluated as well. Building on all these elements, the Test Bed Concentrators were designed and built. With a peak intensity in the focal plane of over 17,500 suns and an average concentrator ratio over 3000 on an eight inch diameter aperture, they have proven to be the work horses of the technology. With a readily adjustable mirror array, they have proved to be an essential tool in the development of dish components, receivers, heat transport systems, instrumentation, controls, engines, and materials - all necessary to cost effective modules and plants. Utilizing the lessons learned from this technology, most cost effective systems were designed. These included Parabolic Dish Number 1 (PDC-1) and PDC-2 currently in final design by Acurex Corporation. Even more advanced concepts are being worked on, such as the Cassegranian systems by BDM Corporation

Parametric study of beam refraction problems across laser anemometer windows

The experimenter is often required to view flows through a window with a different index of refraction than either the medium being observed or the medium that the laser anemometer is immersed in. The refraction that occurs at the window surfaces may lead to undesirable changes in probe volume position or beam crossing angle and can lead to partial or complete beam uncrossing. This report describes the results of a parametric study of this problem using a ray tracing technique to predict these changes. The windows studied were a flat plate and a simple cyclinder. For the flat-plate study: (1) surface thickness, (2) beam crossing angle, (3) bisecting line - surface normal angle, and (4) incoming beam plane surface orientation were varied. For the cylindrical window additional parameters were also varied: (1) probe volume immersion, (2) probe volume off-radial position, and (3) probe volume position out of the R-theta plane of the lens. A number of empirical correlations were deduced to aid the interested reader in determining the movement, uncrossing, and change in crossing angle for a particular situation

Euclidean Supergravity in Five Dimensions

We construct a 5D, N = 2 Euclidean theory of supergravity coupled to vector multiplets. Upon reducing this theory over a circle we recover the action of 4D, N = 2 Euclidean supergravity coupled to vector multiplets.Comment: 13 page

GP prescribing of nicotine replacement and bupropion to aid smoking cessation in England and Wales

Aims Prescribing nicotine replacement therapy (NRT) or bupropion for smoking cessation is of considerable importance to public health but little is known about prescribing practices. This paper examines general practitioners' (GPs') prescribing patterns in Britain where these drugs are reimbursed. The results have implications for other health-care systems considering introducing reimbursement.Design, participants and setting Postal survey conducted in 2002 of a random sample of 1088 GPs in England and Wales, of whom 642 (59%) responded.Measures Number of requests GPs reported having received from patients for NRT and bupropion over the past month, the number of prescriptions they reported issuing and ratings of attitudes to these medications.Findings GPs reported receiving an average of 4.3 requests for NRT and 1.9 for bupropion in the previous month. They reported issuing 3.5 prescriptions for NRT and 1.2 for bupropion. Almost all GPs accepted that NRT (95%) and bupropion (97%) should be reimbursable on National Health Service (NHS) prescription. However, a significant minority of those who received requests for prescriptions did not issue any (81% for NRT and 26% for bupropion). This was related to whether they thought these products should be available on NHS prescription for both NRT and bupropion (OR = 0.66, P < 0.05), which in turn was related to beliefs about whether smokers should have to pay for treatment themselves, the cost-effectiveness of NRT/bupropion and the low priority they would give NRT/bupropion in the drug budget. For bupropion, concern about side-effects independently predicted not prescribing [odds ratio (OR) = 1.46, P < 0.03].Conclusion In the British health-care system, which has a well-established system for technology assessment and professionally endorsed guidelines, a significant minority of GPs decline all patient requests for stop-smoking medicines