Diffusion Reaction Interaction for a Pair of Spheres - ETD ...
Diffusion Reaction Interaction for a Pair of Spheres - ETD ...
Diffusion Reaction Interaction for a Pair of Spheres - ETD ...
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4<br />
that <strong>for</strong> site volumes fractions 10 when the two-sphere problem is explicitly<br />
−<br />
<<br />
included in the N-sink problem, it could improve the bounds on the effective<br />
reaction rate.<br />
1.3 Cell-Cell <strong>Interaction</strong><br />
Bailey and Ollis (1986) outline a number <strong>of</strong> different types <strong>of</strong> cellular<br />
interaction with competition and mutualism described as the two extremes. On<br />
the one hand, competition implies that the presence <strong>of</strong> the second cells results in a<br />
negative effect on the growth rate, i.e. the consumption rate, <strong>of</strong> both cell while<br />
mutualism implies that the two cells are mutually beneficial and hence this<br />
improves the growth rates <strong>of</strong> each species. From published experimental results<br />
(Cooney and McDonald, 1995; Manz, 1999; Raskin et al., 1996; Rauch, 1999;<br />
Stewart et al., 1995 and 1997) it is clear that many if not all <strong>of</strong> these types <strong>of</strong><br />
interaction are occurring within a given system. For instance in a bi<strong>of</strong>ilm, a<br />
highly organized multiphasic system composed <strong>of</strong> cells, water and metabolic<br />
products (Costerton and Stewart, 2001 and De Beer et al., 1994 and 1997),<br />
microbial growth is encouraged by the introduction <strong>of</strong> a substrate (Cao and<br />
Alaerts, 1995), this may stimulate competition between like species <strong>for</strong> say<br />
oxygen (Raskin et al., 1996) or mutualism as a consortium <strong>of</strong> microbes co-<br />
metabolizes hazardous waste (Wanner and Gujer, 1986). There have been many<br />
attempts to solve the biological N-particle system with numerical simulations<br />
while neglecting the importance <strong>of</strong> cellular interaction (Rodriguez, 1983; Beg and<br />
9