CAMP Professors Hopke and Ahmadi Become Directors of Clarkson's New Research Center

Professor Philip Hopke, the Bayard D. Clarkson Distinguished Professor, has been named Director of Clarkson's newly established Center for Air Resources Engineering and Science (CARES). Professor Hopke (of the Departments of Chemical Engineering and Chemistry) is a nationally renowned expert on airborne pollution and was appointed Chair of the U.S. Environmental Protection Agency's Clean Air Scientific Advisory Committee in October 2000. He serves on the Research Strategies Advisory Committee, which is a committee of the Science Advisory Board of the Environmental Protection Agency. Also he is a member of the National Academy of Sciences Committees on Air Quality Management in the United States and on Research Priorities for Airborne Particulate Matter.

Professor Goodarz Ahmadi, Clarkson Distinguished Professor of the Department of Mechanical and Aeronautical Engineering, has been named the Center's Associate Director. Professor Ahmadi has an outstanding reputation for his contributions to research, teaching, and service to Clarkson University. He is involved in world-class fundamental, applied, and experimental fluid mechanics research. His research interests include aerosol transport and deposition, particle and fiber adhesion and removal, surface cleaning, gas filtration, spray, microcontamination control, and multiphase and granular flows.

CARES is a part of the New York State Environmental Quality Systems (EQS), a consortium of universities and research organizations. CARES will develop new modeling, measurement, and flow management tools that can provide the base for new or expanded commercial ventures as well as provide critical information to State and Federal regulatory authorities that will help improve the quality of life for the global community.






















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Professor Greg Campbell, director of CAMP's Extrusion and Mixing Consortium, continues to develop a more descriptive analysis for screw pumps, augers, and extruders. Over the past year much of his group's effort has been focused on the conveying of particular solids with these devices. In addition, his group is working to understand structure development in concentrated two phase systems. They found that bimodal dispersions act quite differently from single particle size systems. Also they have an actual program focused on understanding the reactions and physical changes that occur in an epoxy which forms liquid crystalline structures.

Measurement of Number Concentration of Submicron and Ultra-Fine Particles

There is a growing interest in the measurement of the number concentration of submicron and ultra-fine particles both in the environment and in various industrial settings. CAMP Professor Philip Hopke, the Bayard D. Clarkson Distinguished Professor, and his group are very involved in this work. One of the major hypotheses that has been proposed to explain the adverse health effects of ambient airborne particulate matter is that ultra-fine particles that are present in high number concentrations are the responsible agents. In this case, particle mass that is the currently measured quantity may not be the best indicator of potential adverse consequences. Thus particle number concentration measurements are needed to test this hypothesis. In addition, there are a variety of particle counting needs in industrial settings. With the increased emphasis on nanometer sized particles, particle counters can be important in process control. There is currently only a limited number of instruments available to make such measurements. At Clarkson University, Professor Hopke and his group have been exploring heterogeneous nucleation with a turbulent mixing condensation nuclei counter (TMCNC) with support from the Environmental Protection Agency. Although the concept of a TMCNC has been available for over 15 years, it has been underutilized and could provide an instrument capable of particle detection down to 2 nm and could be developed into a viable commercial instrument. Clarkson University and Rupprecht and Patashnick, Inc., a leading manufacturer of airborne particle monitoring instruments, are developing this instrument into a functional, stand-alone particle counting prototype system that could then be the basis for a commercial product.

Particle Size Analysis and the Use of Particulates in Advanced Materials Processing

Professor Don Rasmussen has published extensively in the areas of nucleation and growth of new phases and on techniques to study nucleation and particle growth processes. Currently his research is focused on the study of characterizing concentrated colloidal systems, particle nucleation in aerosols and the depositing of thin films. His ongoing experimental projects include: (1) measurement of the dynamic light power spectrum from concentrated colloidal systems using a fiber optic probe (being developed to study particle breakdown, aggregation or growth in concentrated systems), (2) determination of the particle size from the shape of the power spectrum and the particle concentration from the integrated power spectral density, (3) nucleation and growth of particles in supersaturated systems (both aerosols in vapors and particles in supersaturated liquors), and (4) the characterization of the hardness and surface properties of CMP polishing pads by surface energy determination and measurement of hardness using nanoindentation resistance.

Granular Flows and Materials

CAMP Professor Hayley Shen, of Clarkson University's Department of Civil and Environmental Engineering, is investigating granular flows in terms of constitutive relations, flow rate effects, particle size and shape effects. She is also interested in two-phase flows. Professor Shen is currently funded by a NASA Microgravity Fluid Physics Program to study the behavior of granular flows in different gravitational fields. This project is being conducted in collaboration with researchers from the University of Florida and Cornell University.

Professor Shen recently made the following conference presentations. ("Plastic to Nonlinear Viscous Transition of Constitutive Relations for Granular Materials - Sample Size Effect," presented at the Powders and Grains 2001, Sendai, Japan, May 2001. "Random Voids and Constitutive Relations for Two-Dimensional Dense Granular Materials," presented at the ASCE-ASME-SES Joint Conference on Mechanics and Materials 2001 (MMC2001), San Diego, June 2001. "Transitional Behavior of Granular Flows," presented at the ASCE/Eng. Mech. Conference, New York, June 2-6, 2002 and "Regime Theory of Granular Flows" presented at the 6th Microgravity Fluid Physics Conference, Cleveland, Aug. 12-16, 2002). Her paper "Sample Size Effects on Constitutive Relations of Granular Materials" appears in the October 2001 issue of the Journal of Engineering Mechanics.

Reverse Magnetostriction, Cyclic Plasticity and Ultra-Fine Grain Nickel

Reverse magnetostriction has been identified as a deformation mechanism in the low plastic strain amplitude fatigue behavior of nickel. Professor David Morrison and Chair of the Department of Mechanical and Aeronautical Engineering Professor John Moosbrugger, working with graduate students Yan Jia and Dong Zhou, have been studying the links between dislocation substructure evolution and the mechanical behavior of nickel during fatigue type loading at a low plastic strain amplitude. They have recently found that anomalies in the shapes of the stress- plastic strain hysteresis loops can be explained on the basis of the magnetostriction of nickel. A detailed model of the coupled reverse magnetostriction and cyclic plasticity behavior of single crystal nickel has been produced. More recently, a grant has been awarded by the National Science Foundation to produce submicron grain size nickel and study its behavior.