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Abstract The natural progression of generators and retailers, following electricity deregulation, to vertically integrate is a contentious subject involving, at one extreme, expectations that a laissez- faire market approach will deliver economic benefits to all participants, and at the other extreme, suspicions that the unusual features of the electricity sector, in providing generators with market power, may not provide electricity consumers with an improved outcome. The objectives of this thesis were to: understand fully the drivers of generators and retailers to vertically integrate and to apply this knowledge to the Queensland electricity market to determine the financial impact on generators, retailers and consumers from vertical integration (VI). A literature review was undertaken of VI in a generic sense, noting the distinction between market contracting and ‘internalisation’, with particular reference to the writings of Oliver Williamson. The Federal Court case involving Australia’s largest electricity retailer, Australian Gas and Light Ltd, seeking approval to purchase a minority shareholding in the Victorian generator Loy Yang Power, was closely examined from the perspectives of theoretical and practical electricity sector VI integration issues. A quantitative analysis was undertaken of an assumed 60% VI of the Queensland electricity market to assess the costs and benefits to generators that vertically integrated and to consumers. The quantified generator benefits included margin elimination, savings in overheads, more rapid decision-making, and demand side management (DSM) savings in deferred capital expenditure on peaking generation and network expenditure through reduced peak demand. To support the quantitative analysis, two scenario models were developed. The first model replicates the process by which generators build up revenue certainty over time from hedge contract sales and bidding of output into the electricity grid. How generator bidding behaviour is affected by the level of hedge cover and hedge contract prices is examined, particularly in regard to how this behavior is affected by the competitive relationship between retailers and generators. The second scenario model replicates the attitude of vertically integrated generators (VIGs) towards offering DSM services by observing how the attitude of individual VIGs is affected by level of peaking generation and by the generation-to-retailing output proportion. It was determined that a combination of these features and particular market scenarios could result in some VIGs being financially worse off by providing DSM services, an important conclusion in the context of the increased community focus on energy conservation. The extent to which VIGs pass on VI and DSM benefits to consumers was calculated under scenarios of weak and strong retail competition. Of most relevance was the difference in market behaviour between retailers that had became vertically integrated, and those that had not, with the latter expected to become less competitive in both the wholesale and retail markets. This outcome was observed to provide generators with additional market power potential, a subject closely examined. The quantitative analysis of the Queensland market concluded that the maximum possible benefit that consumers could expect from VI was $138 million per annum with current DSM technology and strong retail competition, increasing to $156 million per annum if DSM technology improved, for example in regard to more cost-efficient meters. Total possible benefits to VIGs and consumers was estimated at $321 million per annum, so that consumers could expect to receive no more than 50% of total expected benefits from VI. This conclusion is not surprising because generators will only seek to be vertically integrated if they perceive clearly identified benefits from VI. The reasons why consumers are unlikely to receive benefits greater than this are: • $30 million per annum of internal savings being retained by VIGs; • VIGs achieving a minimum $60 million per annum additional revenue benefits through wholesale and retail price increases, arising from their stronger generation and retail positions; and • $75 million per annum of potential DSM benefits not being offered to consumers, because of the reluctance of VIGs to provide DSM services where the outcome could be reduced export revenue, reduced sales revenue and lower pool prices. In summary, using the Queensland market as a case study, in a strongly competitive retail market consumers could expect to receive, at the most, 50% of VI and DSM benefits. However in a weakly competitive retail market, where VIGs retain most of the benefits and are able to achieve higher wholesale prices, the outcome could instead be an overall cost to consumers. The thesis concludes with a brief discussion of policy implications and approaches to addressing key issues arising from increasing VI in deregulated electricity markets.

Thesis (Ph. D.)--University of Michigan, 1930. / "By A.L. Ferguson and G.M. Chen." From the Journal of physical chemistry, v. 36, no. 4, April, 1932.

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This thesis reports the optical properties of InAlAs QDs and InGaAsN QWs grown by Molecular Beam Epitaxy (MBE) on both the conventional (100) and high Miller index surfaces. InAlAs QDs on AlGaAs matrix are grown by MBE on the conventional (100) and non-(100) GaAs substrates using different growth conditions, namely, growth temperature, different confinement barriers, and amount of deposited material. PL measurements revealed differences in the optical properties that are caused by substrate orientation effects. The PL emission energies of QDs grown on high Miller index surfaces such as (311)A and (311)B are found to be strongly dependent on the atomic terminated surface [A (Ga face) or B (As face)] of the substrate. The QDs grown on (311)B plane show superior optical properties over QDs grown on (311)A and (100) planes. The optimum structure to achieve the highest optical efficiency of QDs emitting in the visible red part of electromagnetic spectrum ( ̴ 666 nm) consisted of 4.4MLs Al0.35In0.65As/Al0.45Ga0.55As QDs grown on (311)B plane at a growth temperature of 550 0C. In addition, a further investigation was carried out to study the effect of post-growth thermal annealing on the optical properties of InAlAs QDs grown on (100), (311)A, and (311)B planes. A noticeable enhancement of the PL intensity at 10 K for all planes was observed by increasing the annealing temperature up to 700 0C. Thermal annealing of (311)A InAlAs/GaAlAs QDs resulted in a negligible blue shift, while a large blue shift was observed from (311)B and (100) QDs. This is explained by the smaller size of QDs, smaller strain, and lower In segregation from (311)A GaAs orientation. PL and Transmission Electron Microscopy (TEM) have been used to investigate the optical and structural properties, respectively, of In0.36Ga0.64As1-yNy/GaAs double quantum wells (QWs) grown both on the conventional (100) and non-(100) GaAs substrates. These include In0.36Ga0.64As1-yNy/GaAs QWs with three different compositions of nitrogen, namely, 0%, 1%, and 2%. QWs grown on (311)A GaAs plane show higher nitrogen incorporation over all the other planes. TEM measurements show that (311)B QWs have inferior structural properties than QWs grown on (311)A and (100). TEM images demonstrated that the (311)B QWs interfaces are undulated and not uniform. In contrast QWs grown on (311)A and (100) display very uniform and very flat interfaces. The effect of thermal annealing on the optical properties of In0.36Ga0.64As1-yNy/GaAs double QWs grown on different planes was investigated for two sets of samples having 0% and 1% nitrogen. It was found that annealing at 700 0C for 30 seconds is the optimum annealing temperature which improves the PL efficiency for all QWs. The PL enhancement is larger in samples with 1% nitrogen than 0%.

In this thesis photovoltaic and photocatalytic water-splitting dye complexes have been studied adsorbed onto the rutile TiO2(110) surface. The photovoltaic dye-sensitizer N3 (cis-bis(isothiocyanato)bis(2,2’-bipyridyl-4,4’-dicarboxylato)-ruthenium(II)) was studied along with Ru 455 (cis-bis(2,2’-bipyridyl)-(2,2’-bipyridyl-4,4’-dicarboxylic acid) ruthenium(II)) and Ru 470 (tris(2,2’-bipyridyl-4,4’-dicarboxylic acid) ruthenium(II)) which have very similar chemical structures. Dipyrrin-based dye complexes PY1 bis(5-(4-carboxyphenyl)-4,6-dipyrrin)bis(dimethylsulfoxide)Ruthenium(II)) and PY2 (bis(5-(4-carboxyphenyl)-4,6-dipyrrin)(2,2’-bipyridine) Ruthenium(II)) were also studied which should have different bonding geometries on the TiO2 surface. A single centre water-splitting dye complex (aqua(2,2’-bipyridyl-4,4’-dicarboxylic acid)-(2,2’:6’,6”-terpyridine) Ruthenium(II)) was studied along with a chloride containing analog ((2,2’-bipyridyl-4,4’-dicarboxylic acid)-(2,2’:6’,6”-terpyridine)chloride Ruthenium(II)). The molecules studied here would have been damaged using traditional UHV deposition techniques so electrospray deposition was used to deposit intact molecules in situ for experiments in UHV. Adsorption geometries of the molecules on the TiO2 surface were investigated using experimental photoemission data supported by density functional theory (DFT) calculations. Dipyrrin-based dye complexes were found to bond with both available carboxylic acid groups to the TiO2 surface. Also the results suggest that Ru 470 is most likely to bond to the TiO2 surface with a different bonding geometry to other bipyridine-based complexes with very similar chemical structures. The molecular orbitals of the dye complexes were investigated using near-edge x-ray absorption fine structure spectroscopy (NEXAFS). DFT calculations provided possible spatial distributions of the molecular orbitals involved in charge transfer. Energetic alignments were performed using data from visible light spectroscopy to compare energetics for core and valence-hole excitation. The core-hole clock implementation of resonant photoemission spectroscopy was used to measure upper limits on the timescale of charge transfer from the excited adsorbate molecules to the TiO2 surface. The results show charge transfer timescales mostly within the low-femtosecond timescale. The Ru 470 complex was found to be relatively slow at charge transfer possibly due to the different bonding geometry it appears to adopt on the TiO2 surface.

Lattice mismatched heterostructures grown by Interfacial Misfit (IMF) technique, which allows the strain energy to be relieved both laterally and perpendicularly from the interfaces, are investigated. However, electrically active defects are created at the interface and away from the interface with energy levels deep in the bandgap of the host materials. These defects dramatically affect the optical and electrical properties of the devices. In this thesis, an investigation of deep level defects is carried out on GaSb/GaAs uncompensated and Te compensated heterostructures grown by the IMF method using DLTS, Laplace DLTS, I-V, C-V, C-F and C-G-F measurements. Furthermore, the effect of thermal annealing treatments on the defect states is also studied on both types of samples. It was found that the well-known EL2 electron trap is commonly observed near to the interface of both uncompensated and Te compensated GaSb/GaAs IMF samples. However, several additional electron defects are detected in Te compensated samples. Rapid thermal annealing performed on uncompensated samples resulted in the annihilation of the main electron trap EL2 at a temperature of 600 oC. On the other hand rapid thermal annealing and conventional furnace annealing were carried out on Te compensated samples, and it was observed that rapid thermal annealing process is more effective in terms of defects reduction. The density of interface states is determined from C-G-F and forward bias DLTS measurements. Te compensated samples exhibit the highest density of interface states and have additional hole traps as compared to uncompensated samples. The electrical properties of p-i-n GaInAsSb photodiodes grown on uncompensated and Te compensated GaSb/GaAs templates on GaAs substrates using special growth mode are investigated. The non-radiative defects which could have detrimental effects on the performance of these photo diodes are studied here for the first time. Both electron and hole defects are detected, and their capture cross-section measurements reveal that some of defects originate from threading dislocations. The double pulse DLTS measurements are performed and the concentration distributions of the detected defects are determined.

Dynamic nuclear polarization (DNP) is a technique for enhancing the sensitivity of nuclear magnetic resonance (NMR) experiments by increasing the polarization of the nuclear spins. DNP experiments are often characterized by the enhancement which is achieved, and the enhancement build-up rate. These parameters are strongly influenced by electronic and nuclear relaxation processes. The purpose of the work presented in this thesis was to develop hardware and analysis methods for studying relaxation in electron paramagnetic resonance (EPR) and NMR. Two novel probes for combined NMR and longitudinally detected EPR experiments have been built. The first of these probes is designed for low temperature NMR, EPR and DNP experiments, with the main focus being relaxation studies in typical low-temperature DNP conditions. The second probe is designed for high temperature cryoporometry studies of lignin degradation. Relaxation data in magnetic resonance often exhibits multi-exponential decay. An algorithm for performing a Laplace inversion of multi-exponential relaxation data, and extracting distributions of time constants, is described. The algorithm, which is based on Tikhonov regularization, uses a uniform penalty and a zero-crossing penalty to stabilize the solution, but does not use a non-negativity constraint, so relaxation spectra with both positive and negative peaks can be produced. Two experiments to study relaxation and other dynamic processes in samples containing organic radicals have been performed. The first of these was designed to study saturation, relaxation and spectral diffusion processes in EPR during continuous microwave irradiation. The second experiment measured relaxation of DNP-enhanced nuclear polarization, and revealed an offset dependence of the relaxation behaviour. Both experiments were performed using the low-temperature probe, and the data was analysed using the Laplace inversion algorithm.

This thesis describes the development and applications of quantitative MRI and combined EMG and MRI study of Brachial Plexus. The protocols developed in this thesis have been used on normal healthy subjects, aiming at characterizing the tissues based on their MR and EMG parameters. The Brachial Plexus is the upper portion of the peripheral nervous system and controls the movements of shoulder and arms. Neurological disorders in the brachial plexus can result from cervical spondylotic neuropathy due to compression of nerve roots exiting from vertebra or compression of the spinal cord due to bulging discs. MRI provides the opportunity to obtain precise information on the location of these disorders and to provide quantitative biomarkers. EMG in the form of the distribution of F-latency (DFL) is a recently introduced nerve conduction parameter that can detect functional symptoms with such disorders. To study the brachial plexus the diffusion weighted MRI with body signal suppression (DWIBS) technique was used to highlight the nerves from surrounding tissues. This technique was then used to investigate the diffusivity of water molecules in the peripheral nerve axon. The diffusion time dependency of the diffusion coefficient was used to study the presence of restricted diffusion in the brachial plexus. A clear reduction of the apparent diffusion coefficient was observed with long diffusion times and confirmed the restricted diffusion in nerves and cord. The T2 relaxation was used to investigate the properties of intercellular and intracellular space in peripheral nerves. Diffusion weighting dependency of T2 and echo time dependency of apparent diffusion coefficient (ADC) was observed in initial studies. The magnetisation transfer (MT) and z-spectra were used to study macromolecular characteristics and exchange mechanisms. Asymmetry in z-spectra both for nerves and spinal cord was observed, this relates to possible detection of the nuclear overhauser effect (NOE) in the brachial plexus. Quantitative MRI studies showed that these parameters can be used as important biomarkers for neurological studies in the brachial plexus. The DFL, representing the motor nerve fibres conduction characteristics, was measured for normal healthy nerves and combined with MR parameters. Correlation between DFL and MR parameters was observed for the first time.