Browsing by Author "Kyaruzi, Alexander"

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    Dielectric properties of series joined silicone rubber and epoxy resin formulations
    (University of Dar es Salaam, 2022-10-21) Mushi, Aviti Thadei; Kyaruzi, Alexander
    Dielectric frequency spectroscopy of polymer materials were done in laboratory. The aim was to investigate the (i) differences in dielectric losses of the industrially manufactured silicone rubbers against laboratory manufactured silicone rubbers, (ii) differences in dielectric losses for the epoxy resin samples manufactured in laboratory, but with different curing time, and (iii) differences of dielectric losses between each single polymer to the losses of the series joined specimens of the two polymers. The measurements were done using the Insulation Diagnostics System in laboratory at ambient room conditions. It has been found out that for different frequency ranges, silicone rubber manufactured industrially differ with the laboratory manufactured specimens. The series joined specimens show higher influence of the silicone rubber in both curve shape, and values of losses at frequencies lower than 1 Hz. At frequencies lower than 1 Hz the joined specimen losses are higher than losses for epoxy resin and lower than those for silicone rubber. At frequencies higher than 1 Hz the losses of the joined samples are close but slightly lower to those of epoxy resin and higher than those of silicone rubbers. Lastly, the curves of the joined specimens have shapes which strongly resembles those of the silicone rubbers.
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    Surface Resistivity of Silicone Rubber Formulations Tested in Room Ambient Conditions: The case of silicone rubber formulations with and without filler materials
    (International Conference on Research and Development, 2008-08) Thadei, Aviti; Kyaruzi, Alexander
    Silicone rubber formulations in the form of thin discs have been studied under room ambient conditions for their surface characteristics. The samples were silicone rubber manufactured in laboratory and those industrially manufactured. The measurements were done using an electrometer high resistance meter, applying dc voltage under normal room ambient conditions. The results show that the silicone rubber samples show higher values of surface resistivity when the dc voltage was applied. Silicone rubber samples manufactured in laboratory seem to exhibit erratic behaviour unlike their corresponding silicone rubbers manufactured in industry; this could be due to manufacturing shortcomings in laboratory and the irregularities in the way the silicone rubber adhered to the concentric ring electrodes. The empirical current traversing the surface of the silicone rubbers does not decay exponentially but rather it decays as an exponential power of the energization time.