Effect of water on electrical properties of Refined, Bleached, and Deodorized Palm Oil (RBDPO) as electrical insulating material

This paper describes the properties of refined, bleached, deodorized palm oil (RBDPO) as having the potential to be used as insulating liquid. There are several important properties such as electrical breakdown, dielectric dissipation factor, specific gravity, flash point, viscosity and pour point of RBDPO that was measured and compared to commercial mineral oil which is largely in current use as insulating liquid in power transformers. Experimental results of the electrical properties revealed that the average breakdown voltage of the RBDPO sample, without the addition of water at room temperature, is 13.368 kV. The result also revealed that due to effect of water, the breakdown voltage is lower than that of commercial mineral oil (Hyrax). However, the flash point and the pour point of RBDPO is very high compared to mineral oil thus giving it advantageous possibility to be used safely as insulating liquid. The results showed that RBDPO is greatly influenced by water, causing the breakdown voltage to decrease and the dissipation factor to increase; this is attributable to the high amounts of dissolved water

Typical Internal Defects of Gas-Insulated Switchgear and Partial Discharge Characteristics

Gas-insulated switchgear (GIS) is a common electrical equipment, which uses sulfur hexafluoride (SF6) as insulating medium instead of traditional air. It has good reliability and flexibility. However, GIS may have internal defects and partial discharge (PD) is then induced. PD will cause great harm to GIS and power system. Therefore, it is of great importance to study the intrinsic characteristics and detection of PD for online monitoring. In this chapter, typical internal defects of GIS and the PD characteristics are discussed. Several detection methods are also presented in this chapter including electromagnetic method, chemical method, and optical method

Rational understanding of exsolution process in Ru-doped LaFeO3 perovskite-like for OER

openL’oxygen evolution reaction rappresenta la semireazione di cella limitante nell’elettrolisi dell’acqua, uno dei migliori catalizzatori dell’OER è l’ossido di rutenio, quest’ultimo fa parte dei PGMs e quindi considerato un critical raw material. L’obiettivo della tesi riguarda lo studio della ricostruzione superficiale nella perovskite LaFeO3 drogata con rutenio attraverso l’essoluzione per arricchire la matrice perovskitica del metallo nobile e ottimizzarne l’uso atomico.Oxygen evolution reaction represents the limiting half-cell reaction in the electrolysis of water. One of the best catalysts for OER is ruthenium oxide, the latter being part of the PGMs and therefore considered a critical raw material. This work aims to study the surface reconstruction of a Ru-doped LaFeO3 perovskite-type using exsolution to enrich ruthenium over the parent oxide and optimize its atomic use

Development of Novel Anode Materials for Lithium Ion Batteries

This thesis focuses on the development of new anodes for Li ion batteries. Aluminium has been long considered as promising anode material for Li ion batteries because of its low cost, abundance, and low toxicity. Aluminium undergoes alloying with lithium through intermetallic LiAl formation which offers a relatively high theoretical capacity of 993 mAh/g compared to 372 mAh/g for graphite that is currently the principal anode material in commercial Li ion batteries. However, despite intensive research, all aluminium-based anodes tested so far suffered from rapid capacity fading and failure within first few cycles. Furthermore, there is insufficient understanding of the mechanisms of such capacity fading and the lack of ideas how to overcome this problem. In this work, we were able to demonstrate that the problems that have been plaguing Al anodes are not insurmountable and can be solved by judicious selection of the anode materials, their conditioning and treatment, as well as battery design. An important difference from all other studies is that we propose and justify the use of electrochemical approach to formation of the LiAl nanostructure directly on the bulk anode surface, as opposed to usual methods tested in the literature that involve application of various kinds of nanoparticles, nanowires, as well as thin evaporated or sputtered films. Using the approach developed in this work, we were able to fabricate and test battery prototypes with Al anodes, LiFePO4 cathodes and solid polymer electrolyte that showed sustained performance for more than 400 cycles over wide range of charge-discharge rates with high output voltage of 2.6 – 2.8 V and over 90% coulombic efficiency without any failure or capacity fading

Carbon nanotube/CeₓSr₁₋ₓFeᵧCo₁₋ᵧO₃ perovskite nano-composites: synthesis and physical-chemical characterization for low to intermediate temperature solid oxide fuel cells.

Master of Science in Chemistry. University of KwaZulu-Natal, Durban 2015.Abstract available in PDF file