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Book Use of Microgravity to Control the Microstructure of Eutectics

Download or read book Use of Microgravity to Control the Microstructure of Eutectics written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-20 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: This grant began in June of 1996. Its long term goal is to be able to control the microstructure of directionally solidified eutectic alloys, through an improved understanding of the influence of convection. The primary objective of the present projects is to test hypotheses for the reported influence of microgravity on the microstructure of three fibrous eutectics (MnBi-Bi, InSb-NiSb, Al3Ni-Al). A secondary objective is to determine the influence of convection on the microstructure of other eutectic alloys. Two doctoral students and a masters student supported as a teaching assistant were recruited for this research. Techniques were developed for directional solidification of MnBi-Bi eutectics with periodic application of current pulses to produce an oscillatory freezing rate. Image analysis techniques were developed to obtain the variation in MnBi fiber spacing, which was found to be normally distributed. The mean and standard deviation of fiber spacing were obtained for several freezing conditions. Eighteen ampoules were prepared for use in the gradient freeze furnace QUELD developed at Queen's University for use in microgravity. Nine of these ampoules will be solidified soon at Queen's in a ground-based model. We hope to solidify the other nine in the QUELD that is mounted on the Canadian Microgravity Isolation Mount on MIR. Techniques are being developed for directional solidification of the Al-Si eutectic at different freezing rates, with and without application of accelerated crucible rotation to induce convection. For the first time, theoretical methods are being developed to analyze eutectic solidification with an oscillatory freezing rate. In a classical sharp-interface model, we found that an oscillatory freezing rate increases the deviation of the average interfacial composition from the eutectic, and increases the undercooling of the two phases by different amounts. This would be expected to change the volume fraction solidifying and the fiber spacing. ...

Book NASA Conference Publication

Download or read book NASA Conference Publication written by and published by . This book was released on 1999 with total page 746 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Microgravity Science and Applications Program Tasks

Download or read book Microgravity Science and Applications Program Tasks written by United States. Office of Space Science and Applications and published by . This book was released on 1991 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Scientific and Technical Aerospace Reports

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Chemical Abstracts

Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2710 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Experimental Methods for Microgravity Materials Science Research

Download or read book Experimental Methods for Microgravity Materials Science Research written by Robert A. Schiffman and published by Minerals, Metals, & Materials Society. This book was released on 1988 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceeding of the Second International Symposium on [title] held Feb., 1988, Phoenix, Ariz. The 25 papers included in this volume detail research techniques being used in earth-based simulations, and also planned experimentation techniques to be used upon resumption of the space shuttle program. No

Book NASA Reports Required by Congress

    NASA Reports Required by Congress

    Book Details:
  • Author : United States. Congress. House. Committee on Science, Space, and Technology. Subcommittee on Space Science and Applications
  • Publisher :
  • Release : 1989
  • ISBN :
  • Pages : 686 pages

Download or read book NASA Reports Required by Congress written by United States. Congress. House. Committee on Science, Space, and Technology. Subcommittee on Space Science and Applications and published by . This book was released on 1989 with total page 686 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book 37th AIAA Aerospace Sciences Meeting and Exhibit

Download or read book 37th AIAA Aerospace Sciences Meeting and Exhibit written by and published by . This book was released on 1999 with total page 684 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Japanese Science and Technology

Download or read book Japanese Science and Technology written by and published by . This book was released on 1986 with total page 724 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book NASA Technical Memorandum

Download or read book NASA Technical Memorandum written by and published by . This book was released on 1994 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book A Midterm Assessment of Implementation of the Decadal Survey on Life and Physical Sciences Research at NASA

Download or read book A Midterm Assessment of Implementation of the Decadal Survey on Life and Physical Sciences Research at NASA written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2018-06-09 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 2011 National Research Council decadal survey on biological and physical sciences in space, Recapturing a Future for Space Exploration: Life and Physical Sciences Research for a New Era, was written during a critical period in the evolution of science in support of space exploration. The research agenda in space life and physical sciences had been significantly descoped during the programmatic adjustments of the Vision for Space Exploration in 2005, and this occurred in the same era as the International Space Station (ISS) assembly was nearing completion in 2011. Out of that period of change, Recapturing a Future for Space Exploration presented a cogent argument for the critical need for space life and physical sciences, both for enabling and expanding the exploration capabilities of NASA as well as for contributing unique science in many fields that can be enabled by access to the spaceflight environment. Since the 2011 publication of the decadal survey, NASA has seen tremendous change, including the retirement of the Space Shuttle Program and the maturation of the ISS. NASA formation of the Division of Space Life and Physical Sciences Research and Applications provided renewed focus on the research of the decadal survey. NASA has modestly regrown some of the budget of space life and physical sciences within the agency and engaged the U.S. science community outside NASA to join in this research. In addition, NASA has collaborated with the international space science community. This midterm assessment reviews NASA's progress since the 2011 decadal survey in order to evaluate the high-priority research identified in the decadal survey in light of future human Mars exploration. It makes recommendations on science priorities, specifically those priorities that best enable deep space exploration.