Performance Verification of the Raptor Guard Installed in Sub Transmission Systems

abstract: In sub transmission systems, many more raptor deaths have been recorded near metal poles rather than wood poles. The metal pole, which is reliable in structure but also grounded, may increase the risk of electrocution when raptors perch on the insulator. This thesis focuses on evaluating the effectiveness of the raptor guard to prevent both debilitating and lethal electrocutions to local wildlife in 69 kV sub transmission systems. First, the two-dimensional (2D) finite difference methods (FDM) were proposed to solve the Poisson and Laplace equations, which describe the electric field. Second, the verification of the FDM algorithm was made based on a parallel-plate capacitor model. Then, the potential and the electric field were simulated by the raptor-insulator model to evaluate the possibility of flashover and leakage current under various conceivable scenarios. Third, several dielectric performance experiments were implemented to gain insight into the physical property of the raptor guard developed by the Salt River Project (SRP) as an example. The proposed initial-tracking-voltage and time-to-track experiments tested the ability of the guard, which is designed to prevent the tracking phenomenon under a contaminated situation such as rain, fog, and snow. A data acquisition also collected the leakage current data for the comparison of maximum raptor tolerance. Furthermore, the puncture voltage of this guard material was performed by the dielectric breakdown voltage experiment in an oil-covered container. With the combination of the model simulation and the experiments in this research, the raptor guard was proven to be practical and beneficial in sub transmission system.Dissertation/ThesisMasters Thesis Electrical Engineering 201

Exploratory analysis of pH reference materials for quality control acceptance by chemometrics algorithms

O National Institute for Standards and Technology (NIST) tem procedimentos definidos para a aceitação dos seus Materiais de Referência Certificados (MRC) para medição de pH. Estes procedimentos são morosos e destrutivos para a amostra. A sua substituição por métodos quimiométricos recorrendo a técnicas de análise não destrutivas traria grandes benefícios, por um lado em termos da rapidez e simplicidade do procedimento de aceitação de MRC. Neste trabalho recolheram-se espectros no infravermelho próximo (NIR) e espectros Raman e trataram-se os dados através de análise de componentes principais (PCA), a fim de realizar uma análise qualitativa de três diferentes MRC de pH: carbonato de cálcio (CaCO3), tetraborato de sódio decahidratado ( bórax) e hidrogeno ftalato de potássio (KHP). O método foi testado para distinguir entre MRCs produzidos pelo NIST e outros materiais candidatos a MRC, assim como amostras comerciais de menor pureza que serviram como controlo negativo. Uma coleção de 87 amostras de CaCO3, 52 amostras de bórax e 63 amostras de KHP foi analisada por espectroscopia NIR e Raman. No caso do CaCO3, o PCA alcançou uma boa discriminação, coerente com o método de referência NIST para aceitação de MRC de pH. No caso do bórax, obteve-se boa discriminação entre as amostras, mas que se revelou inadequada para controle de qualidade dos materiais candidatos. No caso do KHP, a discriminação entre amostras foi insuficiente, mas não exclui a possibilidade de aplicar o método proposto ao controle de qualidade de materiais candidatos visto o método de referência NIST também foi incapaz de distinguir os controlos negativos. A diferenciação obtida por PCA para o caso do CaCO3 foi explicada por difração de raios-X, tendo-se verificado que os diferentes grupos observados por PCA correspondem a diferentes polimorfos de calcite, aragonite e vaterite. No caso do bórax, a análise termogravimétrica revelou que o bórax tende a perder parte de sua água de cristalização ao longo do tempo de armazenamento e se transforma lentamente na forma pentahidratada. A análise por PCA diferenciou grupos de acordo com o grau de hidratação das amostras. As amostras de KHP não foram suficientemente separadas na análise por PCA, com exceção de amostras com maior grau de cristalinidade, o que se explicou devido à presença de água oclusa nos cristais de KHP. Este estudo prova que o uso de quimiometria e sua capacidade de discriminar entre amostras quimicamente diferentes é potencialmente uma ferramenta poderosa para garantir a identidade e a qualidade de MRC para pH, e para simplificar o procedimento de aceitação de novos MRC.Spectra collected with near infrared (NIR) and Raman spectroscopic methods were used along with unsupervised pattern recognition, namely, principle component analysis (PCA), to conduct a qualitative analysis of three different pH materials: calcium carbonate (CaCO3), sodium tetraborate decahydrate (borax) and potassium hydrogen phthalate (KHP). The NIR and Raman based fingerprinting with PCA were tested to distinguish between standard reference materials (SRM‘s) produced by the National Institute of Standards and Technology (NIST), and other potential candidate materials, and commercial samples of lower purity. A collection of 87 samples of CaCO3, 52 samples of borax and 63 samples of KHP were measured by NIR and Raman spectroscopy. In the case of CaCO3, PCA achieved a good discrimination coherent with the NIST reference method for acceptance of pH SRM‘s. In the case of borax, good discrimination was obtained between the samples but inadequate for quality control of candidate materials. In the case of KHP, insufficient discrimination was obtained between samples. This does not exclude the possibility of applying the proposed method to the quality control of candidate materials, because the NIST reference method was also unable to distinguish negative controls from SRMs. The PCA clusters were further explained by X-ray diffraction (XRD) in case of calcium carbonate, which revealed that the PCA discrimination is based on the phase transformation of polymorphs of calcite, aragonite and vaterite. In the case of borax, thermogravimetric analysis (TGA) revealed that borax is not a stable substance but it tends to lose some of its crystallization water and transforms slowly into the pentahydrate. This is in good agreement with the different groups distinguished on the PCA. KHP was characterized by the impurities within the samples. The dominant impurity was proven to be the occluded water. This study proves that the use of chemometrics and its ability to discriminate between chemically different samples could be a powerful tool to assure the identity and quality of the pH buffer materials and to streamline the acceptance procedure of new issues of SRM‘s

Design advances of embroidered fabric antennas

Wearable technology has attracted global attention in the last decade and the market is experiencing an unprecedented growth. Wearable devices are designed to be low-profile, light-weight and integrated seamlessly into daily life. Comfort is one of the most important requirements for wearable devices. Fabric based antennas are soft, flexible and can be integrated into clothing. State of the art textile manufacturing techniques such as embroidery, combined with advanced conductive textile materials can be used to fabricate flexible fabric based on-body antennas. In this thesis, the feasibility of using computerised embroidery in the fabrication of wearable, flexible yet functional fabric based antennas have been examined. The fabric based antennas are embroidered using conductive threads. The most suitable materials for fabricating embroidered antennas have been identified. The embroidered fabric based antenna systems including transmission lines and low-profile detachable connectors have been fabricated and their RF performances have been tested. The optimal manufacturing parameters related to embroidery such as stitch direction, spacing and length have been examined. The repeatability of embroidered antennas, cost estimation, and complexity of manufacturing process have been clearly presented. The results can be used to inform and provide guidelines for the development of representative products that can be mass manufactured. A new simulation approach has been introduced to analyse the anisotropic properties of embroidered conductive threads. Simulations and measurements indicate that the performances of embroidered antennas are affected by the anisotropic surface current due to the embroidered stitches. Exploiting the current direction, a novel non-uniform meshed patch antenna has been designed. Representative results show that the non-uniform meshed structure can significantly reduce more than 75% of the usage of conductive materials for the microstrip antennas with negligible effect on the antenna performance

Studies of an Electrically Conducting Organic Material: Tetrathiafulvalene-7,7,8,8-Tetracyanoquinodimethane

This thesis aims to investigate the electrical properties of the organic charge transfer complex Tetrathiafulvalene-7,7,8,8-Tetracyanoquinodimethane, TTF-TCNQ. This is done through two different experimental techniques: Hall characterization and terahertz measurements. Before performing the experiments, suitable devices for these techniques were designed and produced. The layer of TTF-TCNQ was evaporated by physical vapour deposition on an insulating contact of parylene-N and on metallic chromium. According to these results the most promising layer sequence is TTF-TCNQ deposited on top of parylene-N. The adhesive skills of TTF-TCNQ deposited on different materials was also tested using the standardized adhesion test ASTM D3359-97. Two types of electrical devices were produced, Hall devices and terahertz devices. A third sample was also produced in order to image the material of interest using a scanning electron microscope and to measure the film thickness of the polycrystalline TTF-TCNQ layer and of parylene-N. The electric measurements provided the charge carrier concentrations, the sheet carrier density and the conductivity of TTF-TCNQ. The charge carrier densities were high but the measured conductivity was very low. This indicates that the measurement techniques used here may not be very suitable for the both hole and electron conducting TTF-TCNQ material, as the effect of the oppositely charged charge carriers cancel each other out. Also, polycrystalline TTF-TCNQ, which was used here, seems to have a much lower mobility than single crystalline TTF-TCNQ. When working with the type of one-dimensional conductivity observed in TTF-TCNQ it is therefore important to grow single crystalline TTF-TCNQ when very high conductivities are desired. The thesis provides an idea of charge carrier transport in molecular materials, electrical measurement techniques and how to produce a suitable device for examining TTF-TCNQ using terahertz measurements and Hall characterization

Electronic instrumentation for a 3D electrical impedance tomography application

The thesis aims to present the electronic instrumentation required for an EIT application which aims to make an imaging reconstruction of living cells covered with blank hydrogel. Thus the accuracy of the impedance measurement along the frequency range will have a great importance. The experiments performed are made for a 2D EIT system which allows us to extract useful information for the development of the future 3D system. The thesis is divided into four parts: a theoretical study about the bioimpedance and the EIT, the measurement setup used during the course of the thesis and the possible alternatives, the presentation of the results obtained, discussion of results and the conclusion of the thesis. The HF2IS Impedance Spectroscopy (Zurich Instruments AG, Switzerland) is the measurement equipment used to perform four-terminal impedance measurements. The spectroscopy is located in the laboratory of the BioMediTech Group at FinMedi. A multiplexing system has been designed, consisting of four 16x1 channels multiplexers which will be controlled by the digital outputs of the spectroscopy. Besides, the electronic instrumentation required for the EIT system without the HF2IS spectroscope is presented as an aid to future stages of the project

Organic Reactions of Gallium Phosphide and Silicon Surfaces for Stability and Dye Sensitization.

The primary aim of this thesis is to develop wet-chemical functionalization strategies for GaP(111)A, GaP(111)B, and Si(111) for defect passivation and secondary attachment of molecular species. Analyses were performed that probe the physicochemical and photoelectrochemical properties of modified single crystalline semiconductor surfaces. The motivation for these studies was to augment the interfacial properties of covalent inorganic semiconductors with bulk optoelectronic properties suitable for solar energy conversion processes. Gallium phosphide (GaP) is a potential photocathode material for dye sensitized solar cell applications. However, GaP photocathodes are limited in water by severe oxidation and dissolution. Although passivation strategies have been identified previously that stabilize GaP surfaces, no method to attach molecular species that does not involve a defective native oxide has been yet shown. Further, definitive proof that defects could be removed by surface modification is lacking. Silicon surface chemistry is also of interest because of wide use in photovoltaics and microelectronics. Although much is known about Si surface chemistry, there is presently no demonstration of Si surfaces with densely packed monolayers with low surface defect density, the capability for secondary attachment, and stability in wet environments. Such interfacial properties would enhance compatibility for wet-process steps such as atomic layer deposition or spin casting of aqueous metal oxo cluster solutions. To this end, this thesis describes the following advancements. Chapter 2 describes Williamson ether-type reaction that allows rational attachment of modified Coomassie Blue dye to freshly etched GaP(111)B through atop P atoms. In Chapter 3, GaP(111)A electrodes after chlorination/Grignard reaction sequence exhibited enhanced stability, pH-insensitive band edge energetics, and lower density of surface states. Chapter 4 contains data demonstrating Si(111) surfaces with simultaneously low defect density, high stability, and high hydrophilicity. In Appendix A, additional work is presented that illustrates how these surface chemistries could be applied to GaP nanowires. Appendix B illustrates the influence of surface groups on sensitization trough band edge energy changes. Appendix C summarizes attempts to produce super hydrophobic Si(111) through termination with –CF3 groups.PhDChemistryUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/120654/1/esbrow_1.pd

Spacecraft high-voltage power supply construction

The design techniques, circuit components, fabrication techniques, and past experience used in successful high-voltage power supplies for spacecraft flight systems are described. A discussion of the basic physics of electrical discharges in gases is included and a design rationale for the prevention of electrical discharges is provided. Also included are typical examples of proven spacecraft high-voltage power supplies with typical specifications for design, fabrication, and testing

Microwave cavity perturbation of nitrogen doped nano-crystalline diamond films

Non-contact and non-destructive electrical conductivity measurements of nitrogen doped nano-crystalline diamond films have been demonstrated using a microwave cavity perturbation system. The conductivity of the films was controlled by simply varying the CH4 gas concentration during microwave plasma assisted chemical vapour deposition, thereby promoting the formation of sp2 carbon at the grain boundaries. The presence of sp2 carbon is verified through Raman spectroscopy, x-ray photoelectron spectroscopy and electron energy loss spectroscopy, while scanning electron microscopy confirms an increasing surface area for sp2 to form. The microwave cavity perturbation results show that the measured cavity quality factor varies with CH4 concentration. The extraction of conductivity is achieved through a depolarisation model, which must be considered when the sample is smaller than the cavity and through both electric and magnetic field perturbations. The microwave measurements are comparable to contacting and damaging measurements when the film conductivity is greater than the substrate, thus demonstrating an invaluable method for determining conductivity without the need for depositing any electrodes on the film

Development of Zn-IV-Nitride Semiconductor Materials and Devices

This thesis details explorations of the materials and device fabrication of Zn-IV-Nitride thin-films. Motivation in studying this materials series originates from its analgous properties to the III-Nitride semiconductor materials and its potential applications in photonic devices such as solar cells, light emitting diodes, and optical sensors. Building off of initial fabrication work from Coronel, Lahourcade et al., ZnSnxGe1-xN2 thin-films have shown to be a non-phase-segregating, tunable alloy series and a possible earth-abundant alternative to InxGa1-xN alloys. This thesis discusses further developments in fabrication of ZnSnxGe1-xN2 alloys by three-target co-sputtering and molecular beam epitaxy, and the resulting structural and optoelectronic characterization. Devices from these developed alloys are also highlighted. Initial fabrication was based on the reactive radio-frequency (RF) sputtering technique and was limited to two-target sources and produced nanocrystalline films. Progression to three-target reactive RF co-sputtering for ZnSnxGe1-xN2 (x &lt; 1) alloys is presented, where three-target co-sputtered alloys follow the structural and optoelectronic trends of the initial alloy series. However, three-target co-sputtering further enabled synthesis of alloys having &lt; 10% atomic composition (x &lt; 0.4) of tin, exhibiting non-degenerate doping. The electronic structure of sputtered thin-film surfaces for the alloy series were also characterized by photoelectron spectroscopy to measure their work functions and relative band alignment for device implementation. Low electronic mobilities, degenerate carrier concentrations, and limited photoresponse may stem from the defective and nanocrystalline nature of the sputtered films. To improve crystalline quality, films were grown by molecular beam epitaxy (MBE). MBE ZnSnxGe1-xN2 films on sapphire and GaN were epitaxially grown, overall displaying single-crystalline quality films, higher electronic mobilities, and lower carrier concentrations. Througout experimentation, devices from both sputter deposited and MBE ZnSnxGe1-xN2 alloys films were constructed. Attempts at solid-state and electrochemical devices are described. Devices exhibited some photoresponse, providing a positive outlook for employment of ZnSnxGe1-xN2 alloys in solar cells or photon sensors.</p