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Full-Text Articles in Engineering Science and Materials

Hand-Held Flyback Driven Coaxial Dielectric Barrier Discharge: Development And Characterization, Victor J. Law, Vladimir Milosavljevic, Neil O’Connor, James F. Lalor, Steven Daniels Sep 2008

Hand-Held Flyback Driven Coaxial Dielectric Barrier Discharge: Development And Characterization, Victor J. Law, Vladimir Milosavljevic, Neil O’Connor, James F. Lalor, Steven Daniels

Articles

The development of a handheld single and triple chamber atmospheric pressure coaxial dielectric barrier discharge driven by Flyback circuitry for helium and argon discharges is described. The Flyback uses external metal-oxide-semiconductor field-effect transistor power switching technology and the transformer operates in the continuous current mode to convert a continuous dc power of 10–33 W to generate a 1.2–1.6 kV 3.5 μs pulse. An argon discharge breakdown voltage of ∼768 V is measured. With a 50 kHz, pulse repetition rate and an argon flow rate of 0.5–10 argon slm (slm denotes standard liters per minute), the electrical power density deposited in …


Investigation Of Uv-Led Initiated Photopolymerisation Of Bio-Compatible Hema, Sharon Mcdermott Sep 2008

Investigation Of Uv-Led Initiated Photopolymerisation Of Bio-Compatible Hema, Sharon Mcdermott

Doctoral

Ultraviolet (UV) fluorescent lamps are widely used in photopolymerisation processes. However, there a number of disadvantages to these lamps, namely, their intensity varies over time and has to be constantly monitored. This thesis is concerned with the possibility of replacing these lamps with UV Light Emitting Diodes (UV-LEDs). A number of emission characteristics of both the fluorescent lamp and the UV-LEDs were measured and compared to ensure that the optical properties of the UV-LEDs were equivalent to those of the lamps. From this study it was shown that the UV-LEDs have a quicker warm up time and exhibit a more …


Structure Property Relationships In Electron Donating Systems For Potential Photovoltaic Applications., Jonathan Moghal Jan 2008

Structure Property Relationships In Electron Donating Systems For Potential Photovoltaic Applications., Jonathan Moghal

Doctoral

Conjugated polymers are considered to be one-dimensional semiconductors. In conjugated polymers single and double bonds alternatively bond the carbon atoms along the polymer chain. The loosely bound electrons determine the electronic properties of conjugated polymers. In order to utilise the properties of conjugated polymers in terms of a photovoltaic (PV) device application an acceptor material must be added. The acceptor material used in this study is used in buckminsterfullerence (C60). C60 was selected for this purpose due to its size and the fact that it can accept up to six additional electrons. Ultrafast charge transfers from a conducting polymer onto …


Comparison Of Vacuum Glazing Thermal Performance Predicted Using Two- And Three-Dimensional Models And Their Experimental Validation, Brian Norton, Philip Eames, Yueping Fang, Trevor Hyde, Neil Hewitt Jan 2008

Comparison Of Vacuum Glazing Thermal Performance Predicted Using Two- And Three-Dimensional Models And Their Experimental Validation, Brian Norton, Philip Eames, Yueping Fang, Trevor Hyde, Neil Hewitt

Conference Papers

The thermal performance of vacuum glazing was predicted using two dimensional (2-D) finite element and three dimensional (3-D) finite volume models. In the 2-D model, the vacuum space, including the pillar arrays, was represented by a material whose effective thermal conductivity was determined from the specified vacuum space width, the heat conduction through the pillar array and the calculated radiation heat transfer between the two interior glass surfaces within the vacuum gap. In the 3-D model, the support pillar array was incorporated and modeled within the glazing unit directly. The difference in predicted overall heat transfer coefficients between the two …