clim=32.383; k=8.34e-6*3600; A=105.6;
clime=clim/exp(1);
wD=1; wT=logspace(log10(1e-4),log10(1e4),1000);
c1=clim*exp((wT - sqrt(wT.^2 + 4*k*A*wD.*wT))/(2*k*A*wD));
semilogx([wT(1) wT(end)],[clim clim],'r--',wT,c1,'b',...
    [wT(1) wT(end)],[clime clime],'g-.');
xlabel('wTwD'); ylabel('c1')
legend('c_{lim}','c_1^*','c_{lim}/e','Location','Best')

set(gcf, 'PaperUnits', 'centimeters')
set(gcf, 'PaperPosition', [3 10 11 8.25])
print -depsc 'c1opt.eps'

