function B=beta(i,j)

% beta.m --> Returns the value of the sectionalized coagulation
% kernerl, beta, for the particle population balance
% design problem

global d0 mfr T Po MW mu smf rhos kb R rhog Vo SECT rhomix nu startnum D L k m 
global uz A eps

B=2*kb*T/3/mu*(2+2^((i-j)/3)+2^((j-i)/3))+ 0.31*(eps(m)/nu)^0.5*...
   (3*Vo/2)*(2^(i-1)+3*(2^((2*i+j)/3-1)+2^((i+2*j)/3-1))+2^(j-1));

