125,955 research outputs found

    Further detections of OH masers in carbon stars with silicate features

    Get PDF
    A sample of J-type carbon stars was searched for OH maser emission. The new detection of three OH lines towards two silicate carbon stars is reported. In V778 Cyg, previously known as the main-lines (1665 and 1667 MHz) maser source, the satellite 1612 MHz emission was discovered while in NSV 2814 the main OH lines were detected. The presence of OH maser lines confirms the former suggestion that oxygen-rich material is located in the vicinity (\approx 10151610^{15-16} cm) of silicate carbon stars.Comment: LaTeX2e, 4 pages with 2 figure

    Spatial conductivity measurements on high T(sub c) superconducting films

    Get PDF
    High T(sub c) superconducting thin and thick films have potential applications in future NASA flight projects. In anticipation of film use, the Materials Branch is developing a nondestructive, non-contact method of measuring the spatial variation of conductivity across a film sample. This method uses a computer-controlled, X-Y positioning table to scan a conventional eddy current probe across the surface of a film. The induced changes in impedance caused by variations in film conductivity are recorded during the scanning process. Ultimately the two-dimensional data set is displayed using imaging equipment on a personal computer

    Thermal OH (1667/65 MHz) Absorption and Nonthermal OH (1720 MHz) Emission Towards the W28 Supernova Remnant

    Get PDF
    The W28 supernova remnant is an excellent prototype for observing shocked gas resulting from the interaction of supernova remnants (SNRs) and adjacent molecular clouds (MCs). We present two new signatures of shocked molecular gas in this remnant. One is the detection of main-line extended OH (1667 MHz) absorption with broad linewidths. The column density of OH estimated from the optical depth profiles is consistent with a theoretical model in which OH is formed behind a C-type shock front. The second is the detection of extended, weak OH (1720 MHz) line emission with narrow linewidth distributed throughout the shocked region of W28. These give observational support to the idea that compact maser sources delineate the brightest component of a much larger region of main line OH absorption and nonthermal OH (1720 MHz) emission tracing the global structure of shocked molecular gas. Main line OH (1665/67) absorption and extended OH (1720 MHz) emission line studies can serve as powerful tools to detect SNR-MC interaction even when bright OH (1720 MHz) masers are absent.Comment: 14 pages, 3 figures, one table, to appear in ApJ (Jan 10, 2003

    An historical explanation of the development of occupational health and safety and the important position it now occupies in society

    Get PDF
    Scientific and social (economic and ethical) dimensions of occupational health and safety (OH&S) are discussed. Three broad stages in the development of ethics in Western society are analysed in order to assist in understanding the arrival of moral relativism and constructivism under postmodernism. Against this background three recent stages in the emergence of OH&S are outlined and OH&S is shown to be of key importance to sustainable development. Comment is made about the prospects for survival, under moral relativism, of the duty of care ethic which lies at the heart of OH&S and which has until the present time catalysed professionally responsible innovation and change. It is argued that (1) because OH&S tools and techniques called up in legislation are scientific in nature and apply equally to all under law, and (2) because OH&S is increasingly understood as a profitability strategy, ongoing duty of care appeals for reform may continue to be effective even against the corrosive malaise of moral relativism. OH&S workers are reminded of the contribution their profession can make to safe and civil society and to sustainable development and their responsibility for upholding and promoting the ethical dimension expressed through duty of care
    corecore