when melts are slowly frozen in a vertical ampoule the surface of
the resulting crystal replicates the surface of the ampoule with
which it was in contact. However, many experiments performed in
space gave a surprising result - the resulting crystal had a somewhat
smaller diameter than the ampoule, with a wavy surface sometimes
including miniature walls of China that contacted the ampoule wall.
When the "detached solidification" was obtained, the crystal had
significantly fewer dislocations, grain boundaries, and twins. This
phenomenon remained a puzzling mystery from its discovery in 1975
until 1995 when Professors Regel and Wilcox conceived their Moving
Meniscus Model, which is shown in Figure 13.
13. Schematic diagram of the Moving Meniscus Model for Detached
Modeling of Eutectic Solidification
eutectic alloys solidified in space frequently showed a different
microstructure than when solidified on earth. In an attempt to explain
this, students of Professors Regel and Wilcox have developed many
numerical models over the years. Most recently, the influence of
an oscillatory freezing rate was modeled using a phase-field method.
Most fascinating was the view this provided of the composition field
during eutectic solidification, as illustrated in Figure 14.
14. Example of phase-field calculation for eutectic solidification.
white and black strips on the left are the two phases solidifying
out as pure white component and pure black component. The gray portion
on the right is the melt, with the shading indicating the relative
amounts of black and white components. Note that the white component
is concentrated in front of the freezing black phase, and vice versa.
This is the first pictorial view of the composition field generated
in eutectic solidification. Video clips of the variation in microstructure
due to a changing freezing rate can be downloaded from
(unzip and view with Windows Media Player or equivalent). The results
appear remarkably similar to experimental results, which are also
included in this video file.
information about Professors Regel and Wilcox and their research,
you many contact them by telephone and by email.
(Professor Regel: Call 315-268-7672 or send email to firstname.lastname@example.org
/ Professor Wilcox: Call 315-268-7672 or send email to email@example.com)
Professor Yuzhuo Li Promoted
Yuzhuo Li, of Clarkson University's Department of Chemistry, has
been promoted to Full Professor. He began his career at Clarkson
in 1990 as an Assistant Professor in the Department of Chemistry.
He was promoted to Associate Professor and received tenure in 1996.
Prior to his appointment to Clarkson, he was a Visiting Professor
at SUNY Potsdam and a postdoctoral Research Associate at the University
of Illinois at Urbana-Champaign. In 1999, he held guest professorships
at China's Tianjin University of Light Industry and Yangzhou University.
Li's research focuses on the synthesis, characterization, and applications
of nanomaterials such as emulsions, microemulsions, liposomes, and
semiconductor particles. The scope of his work extends to other
areas including chemical - mechanical planarization (CMP), a critical
process for the manufacturing of advanced computer and microelectronic
devices. His research has been published in scientific journals,
including the Journal of Organic Chemistry, Langmuir, Macromolecules,
and the Journal of the Electrochemical Society.
time at Clarkson, Professor Li has been recognized with several
awards, including Outstanding New Teacher Award, Outstanding Advisor
Award, a J. W. Graham Jr. Faculty Research Award and an Award in
Recognition of Scholarly Excellence. He is a member of the American
Institute of Chemical Engineers, the American Chemical Society,
the American Center for Photobiology, and the Chinese American Chemical
Professor Raymond Mackay Honored in France
Raymond Mackay, of Clarkson University's Department of Chemistry,
was honored at a dinner and Symposium "Atelier des Matériaux Mésoscopiques
et Nanométriques: Soft Matter" held on June 7, 2002 at the Institut
Universitaire de France in Paris. The event was organized by Professor
Marie-Paule Pileni from the University of Pierre & Marie Curie-Paris
VI. Professor Mackay has had connections to France for many years.
He had a sabbatical at CNRS in Strasbourg and was involved in NATO
collaborations at Paris VI. Professor Mackay serves as the Director
of Research and Technology of the U.S. Army Edgewood Chemical Biological
Center at Aberdeen Proving Ground, Maryland.