An observational test of common-envelope evolution

By analysing and modelling the change in the abundance ratio of $^{12}$C/$^{13}$C and $^{16}$O/$^{17}$O on the surface of the lower mass star of a binary during the common-envelope (CE) phase of evolution, we propose a simple observational test of the CE scenario. The test is based on the infrared measurement of either the $^{12}$C/$^{13}$C or $^{16}$O/$^{17}$O ratio of red dwarfs in post-common envelope binaries (PCEB's). In certain cases (main-sequence red dwarf secondaries in PCEB's without planetary nebulae), as well as determining whether or not accretion has occurred during the CE phase, we can determine the amount of mass accreted during the CE phase and hence the initial mass of the red dwarf component prior to the CE phase. In the other cases considered (low-mass red dwarfs in PCEB's and red dwarf's in PCEB's with planetary nebulae) we can only say whether or not accretion has occurred during the CE phase.Comment: uuencoded compressed postscript. The preprint are also available at URL http://www.ast.cam.ac.uk/preprint/PrePrint.htm

Music and Law: Copyrighting a Musical Idea

The law of music copyright, although now quite old, is still relatively young in its development and refinement when compared to other segments of the copyright law. The impediment in its progress is partially due to the technicalities inherent in the discipline itself, and also to the lack of musical sophistication on the part of most law making bodies. Modern day electronic developments in recording and storing sound will do much to facilitate and broaden the scope of the law. Its implementation through a Music-Legal Board of Experts could be the effective step needed in order to overcome the present shortcomings of music copyright law

Replacement of a Major Ventilation Raise at the Homestake Gold Mine

Few tasks are more important to the Ventilation Engineer than planning major airways. This paper presents a case study of the inception, design, installation, cost and performance of a 253 m long, 4.27 m diameter subsurface replacement exhaust raise and its connecting drifts. The original raise served as a component of the primary exhaustway (140 m3/s) and heat rejection sink (8MW) for the deepest production district, responsible for 45% of the mine\u27s total ounce production. The chronology of ground control problems with the original raise and attempts to halt the unraveling are described. Planning for a replacement raise commenced once it was realized that the original raise could not be saved. Computer simulation helped size the new raise and connecting drifts. Selection of the raise location was based on a careful rock mechanics assessment. A temporary ventilation bypass system was designed to minimize production loss in event of a catastrophic failure of the old raise while the new raise was being bored. This failure occurred shortly after the temporary bypass was ready. The new raise system was completed in February 1995 at a cost of $US 1.475 million. The troubles encountered, resistance measurements, and final costs are given, and a comparison of planned and actual performance is made

Multi-frequency fine resolution imaging radar instrumentation and data acquisition

Development of a dual polarized L-band radar imaging system to be used in conjunction with the present dual polarized X-band radar is described. The technique used called for heterodyning the transmitted frequency from X-band to L-band and again heterodyning the received L-band signals back to X-band for amplification, detection, and recording

An intuitive tangible game controller

This paper outlines the development of a sensory feedback device providing a low cost, versatile and intuitive interface for controlling digital environments, in this example a flight simulator. Gesture based input allows for a more immersive experience, so rather than making the user feel like they are controlling an aircraft the intuitive interface allows the user to become the aircraft that is controlled by the movements of the user's hand. The movements are designed to feel intuitive and allow for a sense of immersion that would be difficult to achieve with an alternative interface. In this example the user's hand can become the aircraft much the same way that a child would imagine it