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Contact Info
Mail:
Chemical
Engineering Dept.
MS-362
Rice University
PO Box 1892
Houston, TX 77251-1892
E-mail:
Phone:
713-348-5208
FAX
713-348-5478
Office:
B217 Abercrombie
KYRIACOS
ZYGOURAKIS
A.J. Hartsook Professor in Chemical Engineering
Professor of Bioengineering
Chair of the Department of Chemical and Biomolecular Engineering
Research
Interests:
Cellular
and tissue engineering
Reaction engineering
Education:
Ph.D.
University of Minnesota (1981)
Dipl.
Eng. National Technical University of Athens, Greece (1975)
My research interests span several important areas
of bioengineering and reaction engineering. Applied mathematics, computer
simulations, video microscopy, and digital image processing are integral
parts of my research methodology.
Dynamic
Behavior of Cell Populations Growing Under Mass Transport Limitations: Tissue growth in biomimetic scaffolds is strongly influenced by the dynamics
and the heterogeneity of cell populations. A significant source of heterogeneity
is the depletion of nutrients and growth factors due to transport limitations.
Cells slow down, stop dividing or even die when the concentrations of
key nutrients and growth factors drop below certain levels in the scaffold
interior. As a result, tissue engineers have not yet been able to grow
in vitro tissue samples thicker than a few millimeters for metabolically
active cells.
My group is developing a multi-scale, hybrid framework that integrates
biology with mathematical, computational, and experimental tools to study
heterogeneous cell populations growing in three-dimensional scaffolds.
We use a discrete, stochastic model to describe the population dynamics
of migrating, interacting and proliferating cells. The diffusion and
consumption of nutrients and growth factors are modeled by partial differential
equations that are subject to boundary conditions appropriate for the
bioreactors used in each case. These PDEs are solved numerically and
the computed concentration profiles are fed to receptor-mediated binding/trafficking
models or simplified kinetic expressions (i.e. Monod kinetics) to modulate
cell proliferation rates and migration speeds. To meet the significant
computational requirements of this model, parallel implementations of
the hybrid algorithms have been developed for Linux clusters. Finally,
video microscopy and digital image analysis are used to experimentally
observe the dynamic behavior of cell populations and find how cell migration
and proliferation are influenced by the concentrations of nutrients and
growth factors in the culture media, as well as by cell-substrate interactions.
Optimized Processes for Biodiesel Production: My group is developing
comprehensive models for the biodiesel production process. The kinetics
of the transesterification and saponification reactions are studied
for a variety of feedstocks and process conditions. Transient
reactor models
are then developed to optimize the operation of batch biodiesel reactors
together with their separation and purification units. The process
model is also used to analyze the performance of various semi-batch
and continuous
reactor configurations in order to minimize the production costs and
the environmental footprint of the process.
Gas-solid and Liquid-Solid Reactions: Our research in this area focuses on the dynamic behavior of gas-solid or liquid-solid reacting systems with temporally evolving structures. Theoretical and experimental studies are carried out to determine which structural and process parameters control (a) the reactivity of porous carbonaceous materials and (b) the release rates of bioactive agents from multicomponent bioerodible systems. Video microscopy and digital image processing facilities support the experimental studies on coal pyrolysis and combustion. Our primary objective here is the analysis of transient phenomena such as coal particle swelling, macropore formation and heterogeneous or homogeneous ignitions. This information is then used to develop theoretical models that can guide thel design of coal utilization processes.
Catalytic Reactors for Air Pollution
Control: We are working to develop integrated
computer simulation and visualization tools for the optimal design
of emission control reactors that incorporate some the most advanced
adsorption and catalytic reaction technologies. Computer simulation
is essential for the application of these technologies because of
the complex interactions of transport, adsorption, heterogeneous
reaction and catalyst deactivation phenomena occurring in emission
control reactors. Optimization tools are also incorporated in our
codes to allow for easy determination of optimal values of process
parameters. These simulators will move computer-aided design into
the hands of reactor engineers, so that they can meet the air pollution
control challenges in small and medium-size operations
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