1,720,976 research outputs found
Niti Sma Production Using Ceramic Filter During Pouring The Melt
No full textThe usual process to produce NiTi shape memory alloys (SMA) is by vacuum induction melting (VIM) using graphite crucibles which contaminate the bath with carbon. Carbon reacts with titanium precipitating TiC influencing the matrix composition which, in turn, affects the martensitic transformation temperatures. Furthermore, the presence of TiC makes the final product difficult for mechanically process using cold working steps. In this study, we present preliminary results of our attempt to remove the TiC from the melt using ceramic filters during pouring and analyzed the efficiency of the filtering process and some results will be presented. © 2005 Elsevier B.V. All rights reserved.162-163SPEC. ISS.116120Jackson, C.M., Wagner, H.J., Wasilewski, R.J., (1972) NASA-SP, 5110Koshimizu, S., Yamamoto, S., (1992) Proceedings of 10th CBECIMAT, pp. 449-451Koshimizu, S., Yamamoto, C.S., (1993) REM: Revista Escola de Minas, Ouro Preto, 46 (13), pp. 40-47Andrade, M.S., (1985) Final Project Report, p. 146. , Fundação Centro Tecnológico de Minas Gerais, B.HAndrade, M.S., Silva, J.E., Lara, M.H.S., (1988) Anais do 8 CBECIMAT, pp. 256-259. , UNICAMP, Campinas, S.POtubo, J., Mei, P.R., Koshimizu, S., Martinez, L.G., (1998) The Third Pacific Rim International Conference on Advanced Materials and Processing-PRICM-3, 1, pp. 1063-1068. , M.A. Imam, R. DeNale, S. Hanada, Z. Zhong, D.N. Lee (Eds.) 12-16 July Honolulu, Hawaii, USA The Minerals, Metals and Materials Society, TMSOtubo, J., Rigo, O.D., Moura Neto, C., Kaufman, M.J., Mei, P.R., Scale up of NiTi shape memory alloy production by EBM (2003) J. Physique, IV France, 112, pp. 873-876Otubo, J., Rigo, O.D., Moura Neto, C., Kaufman, M.J., Mei, P.R., Low carbon content shape memory alloy produced by electron beam melting (2004) Mater. Res., 7 (2), pp. 263-267Sutton, W.H., Morris, J.R., (1983) 31st Annual Meeting of the Investment Casting Industry, pp. 901-921. , Dallas, TX, 3-5 OctoberApelian, D., Sutton, W.H., (1984) Fifth International Symposium on Superalloys, pp. 421-432. , 7-11 October Seven Springs, PAJones, S.C., (1989) Proceeding Conference Scaninject V Part 2, pp. 553-572. , 6-8 June Lulea, Swede
The Influence Of Carbon And Oxygen Content On The Martensitic Transformation Temperatures And Enthalpies Of Niti Shape Memory Alloy
No full textThe martensitic transformation temperatures and enthalpies of NiTi shape memory alloy strongly depend on the content of nickel and on carbon and oxygen impurities. Nickel stabilizes the high-temperature phase while carbon and oxygen enrich the surrounding matrix with nickel. In this work it is shown that, as a consequence, the martensitic transformation temperatures and enthalpy changes are lower than specially prepared low-contamination reference samples. Furthermore, the enthalpy changes increase linearly with increasing peak martensitic transformation temperature. This means that the lower the enthalpies, the lower is the peak martensitic transformation temperature suggesting that at some lower temperature no phase change should occur. © 2007 Elsevier B.V. All rights reserved.481-4821-2 C639642J. Otubo, P.R. Mei, S. Koshimizu, L.G. Martinez, In: The Third Pacific Rim International Conference on Advanced Materials and Processing (PRICM 3), M.A. Imam, R. DeNale, S. Hanada, Z. Zhong, D.N. Lee (Eds.), The Minerals, Metals & Materials Society, TMS, vol. 1, 1998, pp. 1063-1068Otubo, J., Rigo, O.D., Moura Neto, C., Kaufman, M.J., Mei, P.R., (2003) J. Physique IV (France), 112, pp. 873-876Otubo, J., Rigo, O.D., Moura Neto, C., Kaufman, M.J., Mei, P.R., (2004) Mater. Res., 7, pp. 263-267Otubo, J., Rigo, O.D., Moura Neto, C., Mei, P.R., (2006) Mater. Sci. Eng. A, 438-440, pp. 679-682Rigo, O.D., Otubo, J., Moura Neto, C., Mei, P.R., (2005) J. Mater. Process. Technol., 162-163, pp. 116-120O.D. Rigo, J. Otubo, P.R. Mei, Proceedings of the 60° Congresso Anual da ABM, Belo Horizonte, MG, Brazil, 25-28 July, 2005, 2412-2420Shugo, Y., Yamauchi, K., Miyagawa, R., Honma, T., (1982) Bull. Res. Inst. Miner. Dress. Metall. (Tohoku Univ.), 38, pp. 11-20Olier, P., Barcelo, F., Bechade, J.L., Brachet, J.C., Lefevre, E., Guenin, G., (1997) J. Physique IV (France), 7 (C5), pp. 143-148Frenzel, J., Zhang, Z., Neuking, K., Eggeler, G., (2004) J. Alloys Compd., 385, pp. 214-223Sawaguchi, T., Kausträter, G., Yawny, A., Wagner, M., Eggeler, G., (2003) Met. Mater. Trans., 34 A, pp. 2847-2859ASTM F-2063-00, Standard specification for wrought nickel-titanium shape memory alloys for medical devices and surgical implants, 2000Verhoeven, J.D., (1975) Fundamental of Physical Metallurgy, , John Wiley & Sons pp. 490-49
The Effects Of Vacuum Induction Melting And Electron Beam Melting Techniques On The Purity Of Niti Shape Memory Alloys
No full textThe usual process to produce NiTi shape memory alloys is by vacuum induction melting (VIM) using graphite crucible that contaminates the bath with carbon. The contamination by oxygen comes from residual oxygen inside the melting chamber. A new alternative process to produce NiTi alloys is by electron beam melting (EBM) using water-cooled copper crucible that eliminates the carbon contamination and the oxygen contamination would be minimized due to operation in high vacuum. This work compares the two processes and shows that the carbon contamination is four to ten times lower for EBM compared to VIM products and that the final oxygen content is much more dependent on the starting raw materials. The purity of the final product should be very important mainly in terms of biomedical applications and the contaminations by carbon and oxygen affect the direct and reverse martensitic transformation temperatures. © 2006 Elsevier B.V. All rights reserved.438-440SPEC. ISS.679682Jackson, C.M., Wagner, H.J., Wasilewski, R.J., (1972) NASA-SP, 5110Otubo, J., Mei, P.R., Koshimizu, S., Martinez, L.G., (1998) The Third Pacific Rim International Conference on Advanced Materials and Processing-PRICM-3, vol. 1, pp. 1063-1068. , Imam M.A., DeNale R., Hanada S., Zhong Z., and Lee D.N. (Eds). Honolulu, Hawaii, USA, 12-16 July, The Minerals, Metals & Materials Society, TMSOtubo, J., Rigo, O.D., Moura Neto, C., Kaufman, M.J., Mei, P.R., (2003) J. Phys. IV Fr., 112, pp. 873-876Otubo, J., Rigo, O.D., Moura Neto, C., Kaufman, M.J., Mei, P.R., (2004) Mater. Res., 7 (2), pp. 263-267Choudhury, A., (1992) ISIJ Int., 32, pp. 554-563Nakayama, T., Kuroda, A., Kurita, K., (1992) ISIJ Int., 32, pp. 583-592Watanabe, S., Suzuki, K., Nishikawa, K., (1992) ISIJ Int., 32, pp. 625-629Lalinyuk, A.N., Trigub, N.P., Zamkov, V.N., Ivasishin, O.M., Markovsky, P.E., Teliovich, R.V., Semiatin, S.L., (2003) Mater. Sci. Eng., A346, pp. 178-188Mitchell, A., (1992) ISIJ Int., 32, pp. 557-562Matsumoto, H., (1991) J. Mater. Sci. Lett., 10, pp. 417-419Matsumoto, H., (1991) J. Mater. Sci. Lett., 10, pp. 596-59
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Effect Of Controlled-rolling Parameters On The Ageing Response Of Hsla-80 Steel
No full textThe addition of copper to microalloyed steels in order to promote precipitation hardening is one of the approaches adopted to develop new materials with high mechanical strength but minimized carbon content to assure good weldability. Besides that, the thermomechanical processing of such alloys can eliminate the subsequent quench and tempering heat treatments required by conventional steels. The effects of controlled-rolling parameters over the ageing response of an HSLA-80 microalloyed steel with 1.10% copper were studied in this work. The relatively weak influence over the ageing response verified when the reheating temperature was elevated from 1100 °C to 1200 °C indicated that copper precipitation is the main mechanism behind the hardening promoted by the ageing treatment; niobium had a secondary role. The strain degree applied during the roughing phase increased the ageing response of the alloy, but an increase in the strain degree applied during the finishing phase had no effect over this aspect. Also, a finishing temperature variation had no significant effect on the ageing response of the HSLA-80 steel. © 2007.1971-3374378Abe, T., Kurihara, M., Tagawa, H., Tsukuda, K., Effect of thermo-mechanical processing on mechanical properties of copper bearing age hardenable steel plates (1987) Trans. ISIJ, 27, pp. 478-484Banerjee, M.K., Ghosh, D., Datta, S., Effect of composition and thermomechanical processing on the ageing characteristic of copper-bearing HSLA steel (2000) Scand. J. Metall., 29, pp. 212-223Gladman, T., (1997) The Physical Metallurgy of Microalloyed Steels, , The Institute of Materials, LondonGorni, A.A., Spreadsheet applications in materials science (1998) Spreadsheets in Science and Engineering, , Springer-Verlag, HeidelbergGorni, A.A., Mei, P.R., Austenite transformation and age hardening of HSLA-80 and ULCB steels (2004) J. Mater. Process. Tech., 155-156, pp. 1513-1518Gorni, A.A., Mei, P.R., Development of alternative as-rolled alloys to replace quenched and tempered steels with tensile strength in the range of 600-800 MPa (2005) J. Mater. Process. Tech., 162-163, pp. 298-303Hornbogen, E., Glenn, R.C., A metallographic study of precipitation of copper from alpha iron (1960) Trans. Metall. Soc. AIME, 218, pp. 1064-1070Krishnadev, M.R., Galibois, A., Some aspects of precipitation of copper and columbium (Nb) carbide in a experimental high strength steel (1995) Met. Trans. A, 26 A, pp. 222-224Wilson, A.D., Hamburg, E.G., Colvin, D.J., Thompson, S.W., Krauss, G., Properties and microstructures of copper precipitation aged plate steels (1988) Proceeding of the Microalloying '88, pp. 259-275. , A.S.M., ChicagoWriedt, H.A., Darken, L.S., The solubility of copper in ferrite (1960) Trans. Metall. Soc. AIME, 218, pp. 30-3
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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