Comparative Studies of Fluid Dynamic Gauging and a Micromanipulation Probe for Strength Measurements

Two measurement techniques have been developed independently at the Universities of Birmingham and Cambridge to determine the strength and deformation behaviour of soft-solid fouling layers on hard surfaces immersed in liquid. The micromanipulation and fluid dynamic gauging techniques were compared directly in parallel studies of removal of baked tomato purée deposits from stainless steel coupons. Both techniques showed marked and quantifiable effects of baking time and hydration time on removal behaviour. Micromanipulation allowed adhesive and cohesive interactions to be explored separately, while the dynamic gauging tests showed changes in deformation mode resulting from differences in adhesive and cohesive strength. The two techniques displayed similar trends and complementary phenomenological detail. Direct quantitative comparison was not straightforward, as the gauging results exhibited noticeably greater scatter, probably because this is a more localised measurement.