Marine epibiosis. II. Reduced fouling on Polysyncraton lacazei (Didemnidae, Tunicata) and proposal of an antifouling potential index

Polysyncraton lacazei is a colonial tunicate (family didemnidae) living in the NW-mediterranean rocky sublitoral. A thorough scanning of numerous colonies revealed that in spite of an apparently heavy local fouling pressure only one fouling species — a kamptozoan — is encountered with some regularity on Polysyncraton. We try to define the epibiotic situation of sessile marine organisms as composed of four epibiotic parameters: longevity or exposure time (A), epibiont load (E), colonizer pool (CP) and fouling-period (FP). Subsequently, these factors are combined to propose an “Antifouling Potential” index: AFP=(1−E/CP)×A/(FP+A). This index is intended to permit evaluating the relative antifouling defense potency to be expected in a given organism in a given epibiotic situation and to compare different cases of epibiosis and fouling

Thermal Oxidation of Sintered Silicon Carbide Used for Diesel Particulate Filter Walls

The temperature dependence of the thermal oxidation of sintered silicon carbide (SiC) used for diesel particulate filter walls (DPF) is investigated. Silicon carbide samples are heated at temperatures between 770 K and 1470 K for different annealing times to study the effect of both the temperature and the duration on the oxidation kinetics. The thickness and composition of the oxide layers are characterized by means of XPS and RBS. Silicon oxycarbides (SiCxOy) are first formed and then silicon dioxide (SiO2) appears above 770 K. Different types of SiO2 layers can be identified. The compounds obtained depend on thermal oxidation conditions