SYNTHESIS AND CHARACTERIZATION OF THERMALLY STABLE DIELECTRIC FLUID FROM AZADIRACHTA INDICA SEED OIL

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dc.contributor.authorUMAR, SADIQ
dc.date.accessioned2016-05-03T10:17:40Z
dc.date.available2016-05-03T10:17:40Z
dc.date.issued2015-11
dc.descriptionA DISSERTATION SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY, ZARIA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF MASTER DEGREE IN PHYSICS DEPARTMENT OF PHYSICS, FACULTY OF SCIENCE AHMADU BELLO UNIVERSITY, ZARIA NIGERIAen_US
dc.description.abstractEpoxy neem and epoxy methyl ester samples have been synthesized and unsaturation which is responsible for thermo-oxidative instability of the oil eliminated through epoxidation reaction. Viscosity study of the samples over temperature range of 30°C to 90°C within intervals of 10°C shows Arrhenius type behaviour. The viscosity of the samples decreased exponentially with increase in temperature. Particle mobility in the samples is a thermally activated process with calculated activation energies of 0.21eV, 0.041eV and 0.038eV for the PNO, ENO and ENOE samples respectively.Dielectric response of the samples within frequency range of 20 Hz to 200 kHz at a temperature of 20°C show frequency independent permittivity which is indicative of a constant dominating charge transport mechanism. Study of loss and electric conduction characteristics of the samples over frequency range of 20 to 200 kHz in the temperature range of 20 to 70°C was also carried out to understand the behaviour of the synthesized oils under electric field.Energy dissipationin the samples decreased with increasing frequency with slope of about -1. Dipolar polarization and ionic conduction dominates losses in the oils at high frequencies. Ions which resulted from the dissociation of molecules and from impurities introduced during processing, dominated electrical conduction in the samples. The measured ac conductivity of the samples is of the order of 10-10 Sm-1 to 10-7 Sm-1 and loss tangent is less than one (˂1.0) in the frequency range considered. The loss tangent and ac conductivity of the samples increased with increase in temperature. Charge transport in the oil samples is a thermally activated process with calculated activation energies of 0.34 eV, 0.37 eV and 0.32 eV for the PNO, ENO and ENOE respectively. Comsol Multiphysics software was used to study field distributions in the fluid on application of high voltages in the range of 1 kV to 10 kV. A comparism of the maximum field produced in natural esters and transformer oils indicates that electric discharge is less favourable in natural ester fluid than in transformer oil. The presence ofair and water (impurities) in the oils led to reduced breakdown strength of the oils and could be source for initiation of surface discharge and consequently breakdown. It is suggested that the vii synthesized fluid is similar to other synthesized natural ester fluid for use in electrical systems and as such could be a viable alternative insulation fluid for use in electrical systems.en_US
dc.identifier.urihttp://hdl.handle.net/123456789/7811
dc.language.isoenen_US
dc.subjectSYNTHESIS,en_US
dc.subjectCHARACTERIZATION,en_US
dc.subjectTHERMALLY STABLE DIELECTRIC FLUID,en_US
dc.subjectAZADIRACHTA INDICA SEED OIL,en_US
dc.titleSYNTHESIS AND CHARACTERIZATION OF THERMALLY STABLE DIELECTRIC FLUID FROM AZADIRACHTA INDICA SEED OILen_US
dc.typeThesisen_US
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