3. Electronic Theses and Dissertations (ETDs) - All submissions

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    Heat transfer and pressure drop of regenerative air pre-heater elements.
    (1998) Gruen, Kristina
    In the present study the thermal and hydraulic performance of heating plates used in regenerative air pre-heater was investigated. Experimental results on new heating surfaces are presented as well as preliminary investigations into plates er.',led by fly ash in the flue gas. In the uneroded state, 12 different plate profile designs were tested. These new packs were tested in different configurations, i.e. with and without braces around the individual plates and with different numbers of plates per plate pack. For some designs the individuality of the packs (repeatability of manufacture) was investigated. In order to establish the accuracy of the test facility, a pack of flat plates was tested and compared with literature results. It is shown that the profile designs with the smallest profile heights have the highest heat transfer coefficient, but also the highest pressure drop. Good performance in one parameter always means bad performance in another parameter. Heat transfer coefficients and pressure drops of the various pack designs are in approximately inversely proportion to the hydraulic diameter. Profiles with a flat counterplate have a lower heat transfer coefficient than profiles with an undulated counterplate. One eroded pack (with 20%, 30% and 40% mass loss) was tested and compared with an uneroded one in terms of heat transfer and pressure drop behaviour. Pressure drop was approximately 15% lower for the eroded plates (irrespective of the extent of erosion) and heat transfer coefficient was essentially unaffected.
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    Thermodynamics of metal-insulator systems
    (1996) Kasl, Charles.
    The properties-of systems which undergo a metal-insulator (MI) transition are currently being extensively studied. Both the transport and thermodynamic properties of these MI systems show interesting behaviour, particularly near the MI transition. A complete theory to describe MI systems does not yet exist. In the present work the focus is on the thermodynamic properties of MI systems, in particular on the specific heat and susceptibility. The thermodynamic properties in the absence of a magnetic field are now well understood, with models such as the two-fluid model giving a good account of the behaviour. In finite magnetic fields the thermodynamic properties are even more interesting and varied. It is the aim of the present work to develop and test models to explain the effects of applying magnetic fields to MI systems. The focus is mainly on phosphorous doped silicon, and the results are gratifying. The theory should, however, also apply to other similar MI systems.
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    The emergence of gravitational spaces
    (2015-02-06) Moolman, Simon
    In this thesis I explore the evidence for whether gravity is an emergent phenomenon. I provide a review of black hole thermodynamics and demonstrate how it provides evidence that gravity is an emergent phe- nomenon. In addition I provide a review of Jacobson's calculation which shows how the Einstein eld equations can be interpreted as a thermo- dynamic equation of state. I then use Jacobson's work and the Seiberg- Witten map to derive a new gravitational equation of state which shows what gravity on a non-commutative manifold would look like.
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