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/Thesis / Masters Thesis Electrical Engineering 2016

The limiting current technique has widely been used to study liquid-solid mass transfer in various reactor configurations. In the present contribution several underlying physical aspects have been investigated in order to improve the design of mass transfer experiments. Experimentally, the significant influence of electrolyte composition and hydrodynamic conditions have been studied and quantified to ensure conditions of high reproducibility. In the course of single phase COMSOL simulations, different electrode configurations have been examined with emphasis on concentration fields and electric current distribution showing a large sensitivity of the experimental configuration on the absolute current values.

The limiting current technique has widely been used to study liquid-solid mass transfer in various reactor configurations. In the present contribution several underlying physical aspects have been investigated in order to improve the design of mass transfer experiments. Experimentally, the significant influence of electrolyte composition and hydrodynamic conditions have been studied and quantified to ensure conditions of high reproducibility. In the course of single phase COMSOL simulations, different electrode configurations have been examined with emphasis on concentration fields and electric current distribution showing a large sensitivity of the experimental configuration on the absolute current values.

The research work focuses on optimizing various parameters for controlling cells using negative dielectrophoresis and entrapping them in droplet microfluidics. This is achieved by developing a conductivity medium, combining CytoRecovery, BSA, and EDTA, to maintain a steady count of single cells with good viability over an extended period. The study involves the optimization of frequency and voltage applied to the electrodes to achieve the desired dielectrophoretic forces for long-term cell manipulation. The optimization is based on simulations performed using myDEP and COMSOL software. Additionally, the stability of the conductivity medium is tested during prolonged electric field applications. Considering the significance of working with cells, ensuring the temperature inside the channels remains within physiological limits is vital. Both COMSOL simulations and physical experiments using Rhodamine B dye are conducted to achieve this objective. Moreover, a well-designed process flow is proposed for performing cellular entrapment in droplets. Finally, a novel microfluidic cleaning protocol has been developed to efficiently eliminate both non-biological and biological contaminants from the microfluidic chamber. This innovative protocol has the potential to enable the reuse of any microfluidic chip that does not possess a functionalized surface. / Forskningsarbetet fokuserar på att optimera olika parametrar för att kontrollera celler med hjälp av negativ dielektrofores och fånga in dem i droppmikrofluidik. Detta uppnås genom att utveckla ett konduktivitetsmedium, som kombinerar CytoRecovery, BSA och EDTA, för att upprätthålla ett jämnt antal enstaka celler med god livsduglighet under en längre period. Studien involverar optimering av frekvens och spänning som appliceras på elektroderna för att uppnå de önskade dielektroforetiska krafterna för långvarig cellmanipulation. Optimeringen är baserad på simuleringar utförda med mjukvaran myDEP och COMSOL. Dessutom testas konduktivitetsmediets stabilitet under långvariga elektriska fälttillämpningar. Med tanke på betydelsen av att arbeta med celler är det viktigt att se till att temperaturen inuti kanalerna håller sig inom fysiologiska gränser. Både COMSOL-simuleringar och fysiska experiment med Rhodamine B-färgämne genomförs för att uppnå detta mål. Dessutom föreslås ett väldesignat processflöde för att utföra cellulär infångning i droppar. Slutligen har ett nytt mikrofluidrengöringsprotokoll utvecklats för att effektivt eliminera både icke-biologiska och biologiska föroreningar från mikrofluidkammaren. Detta innovativa protokoll har potential att möjliggöra återanvändning av alla mikrofluidiska chip som inte har en funktionaliserad yta.