1,968 research outputs found

    Alumni of the First Ten Years of Nippon Foundation/GEBCO Postgraduate Certificate in Ocean Bathymetry Training Program

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    The Nippon Foundation/GEBCO Training Programme is a twelve-month course leading to a Postgraduate Certificate in Ocean Bathymetry (PCOB). It is held at the University of New Hampshire, USA and is helping to develop a new generation of seafloor mappers. The course is now in its 11th year. Funding for the programme is provided by the Nippon Foundation of Japan. The PCOB alumni present at the conference were Eunice Tetteh (Year 9, from Ghana), Norhizam Hassan (Year 8, from Malaysia) and Rochelle Wigley (Year 4, from South Africa) with Kentaro Kaneda (Year 5) and Naoto Ujihara (Year 6) also present as official Japanese delegates. The PCOB programme had four posters on display Alumni of the First Ten Years of Nippon Foundation/GEBCO Postgraduate Certificate in Ocean Bathymetry Training Program Nippon Foundation/GEBCO Postgraduate Certificate in Ocean Bathymetry Alumni perspectives - poster 1 Alumni perspectives - poster

    Nippon Foundation/GEBCO Postgraduate Certificate in Ocean Bathymetry

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    Materials and techniques for model construction

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    The problems confronting the designer of models for cryogenic wind tunnel models are discussed with particular reference to the difficulties in obtaining appropriate data on the mechanical and physical properties of candidate materials and their fabrication technologies. The relationship between strength and toughness of alloys is discussed in the context of maximizing both and avoiding the problem of dimensional and microstructural instability. All major classes of materials used in model construction are considered in some detail and in the Appendix selected numerical data is given for the most relevant materials. The stepped-specimen program to investigate stress-induced dimensional changes in alloys is discussed in detail together with interpretation of the initial results. The methods used to bond model components are considered with particular reference to the selection of filler alloys and temperature cycles to avoid microstructural degradation and loss of mechanical properties

    A proposed configuration for a stepped specimen to be used in the systematic evaluation of factors influencing warpage in metallic alloys being used for cryogenic wind tunnel models

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    A proposed configuration for a stepped specimen to be used in the system evaluation of mechanisms that can introduce warpage or dimensional changes in metallic alloys used for cryogenic wind tunnel models is described. Considerations for selecting a standard specimen are presented along with results obtained from an investigation carried out for VASCOMAX 200 maraging steel. Details of the machining and measurement techniques utilized in the investigation are presented. Initial results from the sample of VASCOMAX 200 show that the configuration and measuring techniques are capable of giving quantitative results

    A systematic plan for the continued study of dimensional stability of metallic alloys considered for the fabrication of cryogenic wind tunnel models

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    Interrelated research and development activities, phased development of stepped specimen program are documented and a sequence for a specific program of machining, validation and heat treatment cycles for one material are described. Proposed work for the next phase of dimensional stability research is presented and further technology development activities are proposed

    The Structure and Properties of Diffusion Assisted Bonded Joints in 17-4 PH, Type 347, 15-5 PH and Nitronic 40 Stainless Steels

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    Diffusion assisted bonds are formed in 17-4 PH, 15-5 PH, type 347 and Nitronic 40 stainless steels using electrodeposited copper as the bonding agent. The bonds are analyzed by conventional metallographic, electron microprobe analysis, and scanning electron microscopic techniques as well as Charpy V-notch impact tests at temperatures of 77 and 300 K. Results are discussed in terms of a postulated model for the bonding process

    Technology for pressure-instrumented thin airfoil models

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    A novel method of airfoil model construction was developed. This Laminated Sheet technique uses 0.8 mm thick sheets of A286 containing a network of pre-formed channels which are vacuum brazed together to form the airfoil. A 6.25 percent model of the X29A canard, which has a 5 percent thick section, was built using this technique. The model contained a total of 96 pressure orifices, 56 in three chordwise rows on the upper surface and 37 in three similar rows on the lower surface. It was tested in the NASA Langley 0.3 m Transonic Cryogenic Tunnel. Unique aerodynamic data was obtained over the full range of temperature and pressure. Part of the data was at transonic Mach numbers and flight Reynolds number. A larger two dimensional model of the NACA 64a-105 airfoil section was also fabricated. Scale up presented some problems, but a testable airfoil was fabricated

    Do Electoral Institutions Have an Impact on Population Health?

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    Cataloged from PDF version of article.There is an emerging political economics literature which purports to show that legislatures elected based on proportional electoral rules spend more and redistribute more than legislatures elected based on majoritarian electoral rules. Going a step further the authors of this paper consider whether degree of electoral proportionality has an impact on population health and, in particular, the health of the least advantaged members of society. A panel of 24 parliamentary democracies for the years 1960–2004 is used to examine the relationship between electoral institutions and health. The authors find that greater electoral proportionality is positively associated with overall population health (as indicated by life expectancy) and with the health of the poorest (as indicated by a reduction in infant mortality). A panel of 17 countries for the years 1970–2004 is then used to show to that electoral permissiveness modifies the impact of health spending on infant mortality

    The impact of regime-type on health: does redistribution explain everything?

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    Cataloged from PDF version of article.Many scholars claim that democracy improves population health. The prevailing explanation for this is that democratic regimes distribute health-promoting resources more widely than autocratic regimes. The central contention of this article is that democracies also have a significant pro-health effect regardless of public redistributive policies. After establishing the theoretical plausibility of the nondistributive effect, a panel of 153 countries for the years 1972 to 2000 is used to examine the relationship between extent of democratic experience and life expectancy. The authors find that democratic governance continues to have a salutary effect on population health even when controls are introduced for the distribution of health-enhancing resources. Data for fifty autocratic countries for the years 1994 to 2007 are then used to examine whether media freedom-independent of government responsiveness-has a positive impact on life expectancy

    Dimensional stability considerations for cryogenic metals

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    Work performed as part of an effort to identify, and where possible separate out, some of the factors that contribute to dimensional stability in cryogenic wind tunnel models is reported. Initial problems were encountered with two dimensional models made of 15-5 PH stainless steel, which warped significantly after being subjected to cryogenic testing in the 0.3 Meter Transonic Cryogenic Tunnel. Subsequently, an effort was undertaken to investigate the mechanisms that could cause model warpage during cryogenic testing. The two basic mechanisms that can lead to warpage are (1) metallurgical structural instability in which one phase transforms partially or fully into a second phase which has a different crystal structure and volume, and (2) deformation due to the creation, or relief, of unbalanced induced or residual stresses. In the case of the 15-5 PH airfoils, it is highly probable that metallurgical instability was responsible for most of the observed warpage. A particular specimen configuration was established for use in the systematic evaluation of the factors influencing warpage. Preliminary studies of a specimen made of VASCOMAX 200 suggest the possibility of manipulating the stresses in the surface layers by appropriate combinations of milling and grinding steps. This opens up the possibility of correcting or establishing the required surface profile of an airfoil
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