CAMP Professor Liya Regel Receives Prestigious Basic Sciences Award
CAMP Professor Liya Regel received the prestigious Basic Sciences Award of the International Academy of Astronautics (IAA) at the International Astronautical Congress in Rio de Janeiro on October 1st. It is the top award in the Basic Science Section of IAA and is given for outstanding achievement in basic science. Professor Regel is the first person in materials science to receive this award, the first in microgravity research, and the first woman. The award recognizes Professor Regel's achievements in several areas as described below:
-First to do heavy-ion bombardment and implantation in compound semiconductors, magnetic semicondutors, & alkali halides.
-Participated in approximately 150 experiments on materials processing in space.
-Explained the 20-year old mystery of detached solidification in space via the Moving Meniscus Model.
-Invented a new technique for high quality diamond film deposition at low pressure and demonstrated selective patterned deposition and coating of carbon fibers and glass.
Modeled the influence of freezing rate changes on eutectic microstructure.
Founded and established the new field of centrifugal materials processing via the following:
-Discovered, verified and explained the non-intuitive result that semiconductor doping becomes uniform when directional solidification is carried out at a particular centrifuge rotation rate.
-Demonstrated that centrifugation greatly improves the deposition of diamond films (see http://www.clarkson.edu/~regel/research.htm).
-Organized and chaired four international workshops on centrifugal materials processing, and edited the four resulting proceedings. (The most recent workshop was held at Clarkson this May. See http://www.clarkson.edu/~regel/workshop.htm.) The proceedings of the third workshop received the Best Basic Science Book Award from IAA at Melbourne in 1998.
-With CAMP Professors Partch and Wilcox, used centrifugation
to produce a sticky, porous membrane of polytetrafluoroethylene (TeflonTM).
Light Scattering Investigation of Particle Aggregation
CAMP Professor Michal Borkovec's central areas of research are the interaction of solutes with colloidal substrates and the aggregation of colloidal particles. These studies have many practical applications. For example, adsorption processes are crucial in determining the transport of solutes in porous media, a process of fundamental importance in environmental chemistry and chromatography. His research involves a time-resolved simultaneous static and dynamic light scattering technique for investigating the early stages of particle aggregation.
Reverse magnetostriction has been identified as a deformation mechanism in the low plastic strain amplitude fatigue behavior of nickel. Professors David Morrison and John Moosbrugger, working with graduate student Yan Jia, have been studying the links between dislocation substructure evolution and the mechanical behavior of nickel during fatigue type loading at low plastic strain amplitude. They have recently found that anomolies in the shapes of the stress- plastic strain hysteresis loops can be explained on the basis of the magnetostriction of nickel. All ferromagnetic materials exhibit strain due to an applied magnetic field, the so-called Joule magnetostriction. In reverse magnetostriction, the imposition of a normal stress induces magnetization along with an accompanying magnetostriction. In nickel, a tensile stress causes net domain magnetization perpendicular to the stress axis, while a compressive stress causes domain magnetization parallel to the stress axis. The result is that at low plastic strain amplitudes, hysteresis loops are constricted due to the magnetic component of inelastic strain that is not dislocation-based. Experiments performed on specimens in the presence of a magnetic field strong enough to maintain nearly fixed domain magnetization under tension-compression cycling showed that these constrictions could be eliminated.. See Figures 8 and 9. In this case nickel will behave much like copper, which produces analogous dislocation substructure in fatigue type loading and which is dimagnetic at room temperature.
Figures 8 & 9. Polycrystalline nickel cycled at a plastic strain amplitude of 0.0001 with and without a strong magnetic field in the direction of the specimen axis. Note the elimination of the constrictions of the hysteresis loop when the magnetic field is applied.
Professor Dayakar Penumadu has been involved with several projects related to characterizing the microstructure, mechanical and flow properties of coated polymeric materials, refractory and granular materials. Also Dr. Penumadu has recently developed a fully automated testing system that uses high magnification digital imaging techniques for evaluating both the particle size and shape distribution of non-cohesive powders and suspension systems for a size range of 5 micrometers to 20 milllimeters. His sponsored projects focussed on: evaluating the microstructural characterization of porous materials (alumina ceramics, and refractory coating material) using digital micrograph analysis and mercury intrusion porosimetry; quantifying the mechanical properties for evaluating optimum composition using non-destructive tests (for elastic moduli) and destructive tests (Modulus of Rupture - MOR values, three-dimensional tests to characterize flow, yield, and failure behavior for frictional materials); and developing an automated digital vision system with a large range of optical magnification for material and on-line product analysis.
In the modeling area, CAMP Professor Dayakar Penumadu has been developing artificial neural network (ANN) based computational models for several companies. The models are being used for advanced materials processing, characterization and behavior.