Nishizawa Receives IEEE Edison Medal
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for control purposes. After grinding the calcined samples into powders, hydration tests were performed by placing the powders into a constant temperature and humidity (96%) chamber for up to four hours. The hydration rate was calculated as the ratio of the weight gain after hydration to the original sample weight. Hydration rates of 0.5% to 1.8% were obtained, with the lower hydration rates generally corresponding to a higher valency of the dopant. The researchers attribute these results to two phenomena. Ca2+ and Mg2+ vacancies formed by reactions with the dopants increase the surface energy and enhance the sintering process, leading to more dense powders. Also, the preferential formation of solid solutions involving high-valency dopants (such as Ti4+) with the more-easily hydrated CaO phase decreases the Ca2+ concentration, reducing the tendency to hydrate. TIM PALUCKA
Alex Zunger to Receive TMS 2001 John Bardeen Award Alex Zunger, NREL’s Research Fellow and leader of the Solid State Theory group (Basic Sciences Center), is the recipient of the John Bardeen Award for the year 2001, presented by the Minerals, Metals, and Materials Society (TMS). He is cited for “his seminal contributions to the theoretical understanding and prediction of ‘spontaneous ordering,’ phase-stability, and electronic properties of semiconductor alloys; for the impact that this work has had on experimental studies of electronic materials, and for his continued leadership in the field. This work centers around Zunger’s pioneering seminal theoretical studies of “spontaneous ordering” in semiconductor alloys—a phenomenon whereby instead of appearing randomly, the atomic constituents of alloys (e.g., gallium and indium in gallium phosphide-indium phosphide) tend to order spatially in geometric arrangements that alter the electronic, transport, and optical properties of the material creating new, technologically significant functions. A more detailed description of this field appears in the group’s web site at www.sst.nrel. gov/topics/alloy_order.html. Zunger said that his work on this theoretical problem was done in collaboration with his postdoctoral fellows since 1983: J. Bernard, D. Laks, K. Mader, R. Magri, J.L. Martins, T. Mattila, A. Mbaye, R. Osorio, V. Ozolins, G.P. Srivastava, and D. Wood, as well as with his NREL associates L. Ferreira, S. Froyen, S.H.Wei, and S.B. Zhang. Zunger’s other areas of interest
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include photovoltaic materials, the theory of semiconductor quantum-dots, and the theoretical design and predictions of stable crystal structures and phase-diagrams. This award will be presented formally to Zunger at the 130th Annual TMS meeting on February 13, 2001, in New Orleans.
Peppas Receives General Electric Senior Research Award Nicholas A. Peppas, the Showalter Distinguished Professor of Chemical and Biomedical Engineering in the School of Chemical Engineering at Purdue University, has been presented with the General Electric Senior Research Award at an awards ceremony held at the annual conference of the American Soci
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