Characterisation of viscoelastic materials through exploitation of the frequency independent gel point (GP) can be used to study blood clotting anomalies. Information regarding the sol-gel transition can be obtained for gelling systems by employing small amplitude oscillatory shear (SAOS) measurements over a range of oscillatory shear frequencies. Analysis of the fractal dimension, , at the GP has previously been used as a biomarker for pathologies related to thromboembolic disease. This thesis investigates the potential adverse clotting characteristics induced by the presence of exhaust particulates using rheometric techniques. SAOS experiments conducted using a combined motor transducer (CMT) rheometer are susceptible to inertial artefacts at high frequencies, leading to potentially significant error in the reported GP. Herein, the development and evaluation of an enhanced rheometer inertia correction procedure (ERIC) is shown to allow valid GP data to be obtained post-acquisition at previously inaccessible frequencies. The potential impact of soot particulates on coagulation is likely to be small due to the weakly elastic gelling systems being studied, thus necessitating the use of the ERIC procedure to remove the presence of any inertial artefacts causing miscalculation of the GP. Fibrin gels were studied as model blood clots to assess the effects of the inclusion of soot particulates on the GP. The impact of the inclusion of increasing concentrations of soot solution on the GP proved inconclusive after the application of ERIC. However, in whole blood clots, the post-ERIC GP data indicated an increase in the density of the clot formed with increasing soot concentration, suggesting an elevated health risk as a possible result of interruption of the clotting cascade due to soot particulates.
Viscoelastic Properties for Sol-Gel Transition
