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Research Publications (Engineering and Built Environment)

Permanent URI for this collectionhttp://ir-dev.dut.ac.za/handle/10321/215

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Author: search.filters.author.Davidson, Innocent EwaenHas files: No

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    Analysis of current Pulses in HeLa-Cell Permeabilization due to high voltage DC corona discharge
    (IEEE, 2016-09) Chetty, Nevendra K.; Chonco, Louis; Ijumba, Nelson M.; Chetty, Leon; Govender, Thavendran; Parboosing, Raveen; Davidson, Innocent Ewaen
    Corona discharges are commonly utilized for numerous practical applications, including bio-technological ones. The corona induced transfer of normally impermeant molecules into the interior of biological cells has recently been successfully demonstrated. The exact nature of the interaction of the corona discharge with a cell membrane is still unknown, how-ever, previous studies have suggested that it is either the electric fields produced by ions or the chemical interaction of the reactive species that result in the disruption of the cell membrane. This disruption of the cell membrane allows molecules to permeate into the cell. Corona discharge current constitutes a series of pulses, and it is during these pulses that the ions and reactive species are produced. It stands to reason, therefore, that the nature of these corona pulses would have an influence on the level of cell permeabilization and cell destruction. In this investigation, an analysis of the width, rise-time, characteristic frequencies, magnitude, and repetition rate of the nanosecond pulses was carried out in order to establish the relationship between these factors and the levels of cell membrane permeabilization and cell destruction. Results obtained are presented and discussed.
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    Dynamic voltage stability studies using a modified IEEE 30-Bus system
    (IEEE, 2016) Oni, Oluwafemi E.; Davidson, Innocent Ewaen; Mbangula, Kamati N. I.
    Power System stability is an essential study in the planning and operation of an efficient, economic, reliable and secure electric power system because it encompasses all the facet of power systems operations, from planning, to conceptual design stages of the project as well as during the systems operating life span. This paper presents different scenario of power system stability studies on a modified IEEE 30-bus system which is subjected to different faults conditions. A scenario whereby the longest high voltage alternating current (HVAC) line is replaced with a high voltage direct current (HVDC) line was implemented. The results obtained show that the HVDC line enhances system stability more compared to the contemporary HVAC line. Dynamic analysis using RMS simulation tool was used on DigSILENT PowerFactory.