SPECIALTY:
- Rheology
- biorheology
- ultrasonics
and suspension mechanics
EDUCATION:
1972 B.S.,
Mechanics and Material Science, The Johns Hopkins University
1973 M.S.,
Mechanics and Material Science, The Johns Hopkins University
1978 Ph.D.,
Mechanics and Material Science, The Johns Hopkins University
POSITIONS HELD:
Postdoctoral Fellow, Chemistry, McGill University, Montreal,
Quebec, 1978-1979
Asst/Assoc Professor,
Chemical Engineering, Washington University, St. Louis, Missouri, 1979-1984 University
of California Davis
Associate
Professor, Chemical Engineering & Materials
Science,1984-199
Professor,
Chemical Engineering & Materials Science, 1990
- Present
Professor,
Food Science & Technology, 2000-present
Department
Chair, Chemical Engineering & Materials Science,
July, 2002 - Present
RESEARCH OBJECTIVES
Suspension dynamics is being studied
by using magnetic resonance (NMR) imaging. Current work focuses on the development of an NMR imaging
viscometer and the use of NMR imaging to measure flows of opaque suspensions,
such as paper pulp suspensions.
Macroscopic rheological properties
of suspensions of spherical and rodlike particles are being investigated. Suspensions
of multisized spherical particles are examined theoretically and experimentally. Using
facing ball rheometry to determine the viscosity of suspensions of rodlike
particles, we have been able to elucidate the effect of particle volume fraction,
aspect ratio, and microstructure. Rheological
studies conducted with pulp suspensions are facilitating the design of new
unit operations for the paper industry.
Biorheological studies are being
carried out to elucidate the mechanical interactions between spermatozoa and
their environment. Long-range
goals of this work include finding a synthetic medium which can be used for
clinical tests and quantitatively determining the role of mucus properties
on fertility.
Experimental and theoretical investigations
have shown that low concentrations of a polymer additive in water can dramatically
alter nonlinear wave propagation in viscoelastic fluids. This
work is being extended to a wider range of non-Newtonian fluids as well as
to suspensions and other fluids with microstructure.
SELECTED PUBLICATIONS:
-
Nuclear magnetic
resonance imaging rheometer. J.E.
Maneval, K.L. McCarthy, M.J. McCarthy and R.L. Powell. 1996. U.S. Patent No. 5532593.
Use of
magnetic resonance imaging as a viscometer for process monitoring. D.F. Arola, G.A. Barrall, R.L. Powell,
K.L. McCarthy and M.J. McCarthy. 1997. Chemical
Engineering Science 52(13):2049-2057.
Rotational
rheometry. R.L. Powell. 1998. p.247-296, IN: E.E. Collyer and D. Clegg (eds). Rheological Measurement, Second Edition, Elsevier.
Flow of pulp
suspensions through a sudden expansion. D.F.
Arola, T.-Q. Li, L. …dberg, R.L. Powell and M.J. McCarthy. 1998. American Institute of Chemical Engineers Journal 44:2597-2606.
Swimming of
spermatozoa in linear viscoelastic fluid. G.
Fulford, D.F. Katz and R.L. Powell. 1998. Biorheology
35:295-310.
Pointwise observations
for rheological characterization. D.F. Arola, G.A. Barrall, R.L. Powell and M.J. McCarthy. 1999. Journal of Rheology 43:9-30.
Experimental
observation of dip coating phenomena and the prospect of using motion control
to minimize fluid retention. J.W.
Krozel, R.L. Powell and A.N. Palazoglu. 2000. Chemical
Engineering Science 55:3639-3650.
Calculation
of the Ewald summed far-field mobility functions for arbitrarily-sized spherical
particles in stokes flow. K. Hase and R.L. Powell. 2001. Physics
of Fluids 13:32-44.
Polymer melt
rheology by magnetic resonance imaging. Y.
Uludag, G. A. Barrall, D.F. Arola, M.J. McCarthy and R.L. Powell. 2001. Macromolecules 34: 5520-5524.
Prediction
of the hydrodynamic transport properties of concentrated suspensions of non-spherical
from their shape and packing behavior. C. Chang and R.L. Powell. 2002. American
Institute of Chemical Engineers Journal 48(11):2475-2480.
In-line measurement of yield stress and shear viscosity
and modeling of apparent wall slip in diced tomato products. N. Dogan, M. J. McCarthy and R. L. Powell. 2003. Journal of Food Science 25:571-587.
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