Integrated building elements, which combine their structural, control and architectural functions with that of energy generation, are expected to become increasingly important in the future scenario of energy efficient buildings, and they could significantly contribute to the thermal behavior of the building envelope in order to provide energy savings. A prototype of a building-integrated photovoltaic thermal (BIPV/T) solar air collector was built, consisting of a double-glazed airflow window wall with photovoltaic (PV) louvers embedded in it. The collector is intended to either be used as a modular window wall unit that would form a ventilated double-skin façade, or as an independent airflow window, and it provides combined heat and power generation, while still allowing light transmission, shading control and thermal insulation as a conventional window.

In this work, the prototype's thermal and electrical performance have been tested, and the experimental data served to develop and validate a thermo-fluid dynamic model in COMSOL Multiphysics. This served as a first reference model and starting point to build more expanded 2D models, as well as to develop 3D models of some portions of the window, which were used for optimization and design by editing the prototype’s features, such as geometrical layout, material properties and operational parameters. CFD simulations were used to enhance PV cooling and thermal insulation, in order to optimize both the thermal and electrical efficiency. The optimization of the glazing system, frame heat losses minimization and several strategies for PV-to-air heat transfer enhancement are discussed. These included parametric analysis of the effects of airflow rate and glass spacing on PV temperature and thermal generation, the use of extended surfaces and a new layer structure of the PV absorbers. The field measurements on existing prototype determined a maximum temperature rise of 31 °C and average thermal and electrical efficiency of 31% and 7%, respectively. The optimization showed that significant increases in air temperature rise and thermal efficiency by up to 70% and 60%, respectively, as well as up to 25% decrease in PV temperature can be achieved. Lastly, the design of new prototypes in SolidWorks, which were developed based on the simulation results, are presented.

Integrated building elements, which combine their structural and architectural functions with that of energy generation, are expected to become increasingly important in the future scenario of energy efficient buildings, and they could significantly contribute to the thermal behaviour of the building envelope in order to provide energy savings. A prototype of a building-integrated photovoltaic/thermal (BIPV/T) solar air collector has been built by a Palo Alto start-up company, and consists on a double pane airflow window wall with photovoltaic (PV) louvers embedded in it. The unit is intended to perform the functions of both thermal and electrical generation, as well as light transmission and shading control. In this work, the prototype's performance has been tested in different outdoor conditions and under different airflow speeds, with the aim of investigating its thermal and electrical capabilities. The results presented in this thesis showed an optimal behaviour during the winter, with a maximum air temperature rise (from bottom to top) of about 30°C and average thermal efficiency of 31%. By using inexpensive PV modules with a rated efficiency of 12.5%, an actual electrical efficiency of 7% was recorded under the maximum operating temperatures.

Microelectrodes are devices through which neural signals are obtained or delivered. The goals for designing microelectrodes are maximum selectivity (ability to select and record from a single cell) and minimum impedance. It is very important to reduce the impedance of metal microelectrodes as much as possible since the main source of noise for metal microelectrodes is thermal noise which is directly related to impedance. Signal to noise ratios are particularly important in the quality of the signal that can be received by the microelectrode.

In order to increase selectivity, small size microelectrodes are desired but as the size of the microelectrode decreases the impedance increases so fabrication of small size microelectrodes with low impedance is always a challenge.

To reduce the resistance of microelectrodes a traditional approach is electroplating them with platinum black, however the impedance of the microelectrode, using this method, is generally unstable. Creating microstructures on electrodes is another approach that has been tried before without a significant success.

This work investigates the problems with the design of microstructures and introduces a novel design and technique to fabricate microelectrodes with significantly lower impedance than traditional flat microelectrodes, yet more stability than the platinum black coating approach.

Over the last decade, the number of implantable neurostimulator systems implanted in patients has been rapidly growing. Nearly 50,000 neurostimulators are implanted worldwide annually. The most common type of implantable neurostimulators is indicated for pain relief. At the same time, commercial use of other electromagnetic technologies is expanding, making electromagnetic interference neurostimulator function an issue of concern. The susceptibility of six active implantable neurostimulators with lead systems to an electromagnetic field generated by 22 radio frequency identification emitters was investigated. It was found that one implantable neurostimulation system was inhibiting the stimulation pulse during low frequency exposure at close distances. To systematically address the concerns posed by EMI, a test platform was developed to assess the interference from coupled magnetic fields on implantable neurostimulator systems. The lifetime of any active neurostimulator system heavily depends on its battery. Current technology has been able to provide solutions to power up such devices for up to five years. In fact, the latest research in this area showed that, on average, batteries last only three years. When an implantable battery needs to be replaced, a surgical procedure is required during this process. In addition, the current available implantable batteries contain potentially hazardous materials to human bodies and if leaked could cause potentially lethal complications. A system was developed that demonstrates a proof of concept based on cascaded concentration cells that can currently deliver 2 µW of power, capable of powering small scale implantable devices. Ideally, the system could replace or charge an existing battery based on concentration differences that already exist within the human body. The system has several advantages over the current implantable batteries and other proposed technologies. The most important advantage is the use of flexible, biocompatible materials. The system does not use toxic or nuclear materials and does not depend on energy sources outside of the human body or body movement. It does not heat body tissue, or require a cosmetic disadvantage. It makes use of renewable energy sources within the human body.

With the advent of aberration corrected electron microscopy, the need for ultra stable power supplies for controlling the currents in magnetic lenses becomes one of the limiting factors in attaining atomic resolution. When we talk about resolution and depth of the field it is always assumed that all the components of the microscope are perfect and will focus the light/electron from any point on the object to a similar unique point in the image, but this is not the case because of the lens aberrations and diffraction. Unlike light optics, where lenses are used to refract and bend light rays for image formation, in electron optics magnetic lenses are used to do the same thing. Magnetic force is used to change the direction of electrons in the same way that a lens changes the direction of light rays. Therefore one of the limiting factors of resolution in electron microscopy is variation of the current that creates the magnetic field. With the advancement in lowering aberrations in electron microscopic lenses the need for higher stability in the lens current supplies becomes paramount. In order to achieve resolution of 0.5 angstrom level or better we need current supplies that are stable up to 1 part in 10-8. In this work, the aim is to design a high stability current supply capable of producing 1 Amp of current within 0.01 parts per million (ppm) of stability for electron microscopy. In this thesis, an ultra stable current supply was designed and simulated. The stability of the current is 0.0086 ppm/OC, over 15 minutes which is within the range that is required for this design.

Solar energy has long been lauded as an inexhaustible fuel source with more energy reaching the earth's surface in one hour than the global consumption for a year. Although capable of satisfying the world's energy requirements, solar energy remains an expensive technology that has yet to attain grid parity. Another drawback is that existing solar farms require large quantities of land in order to generate power at useful rates. In this work, we look to luminescent solar concentrator systems and quantum dot technology as viable solutions to lowering the cost of solar electricity production with the flexibility to integrate such technologies into buildings to achieve dual land use.

Luminescent solar concentrator (LSC) windows with front-facing photovoltaic (PV) cells were built and their gain and power efficiency were investigated. Conventional LSCs employ a photovoltaic (PV) cell that is placed on the edge of the LSC, facing inward. This work describes a new design with the PV cells on the front-face allowing them to receive both direct solar irradiation and wave-guided photons emitted from a dye embedded in an acrylic sheet, which is optically coupled to the PV cells. Parameters investigated include the thickness of the waveguide, edge treatment of the window, cell width, and cell placement. The data allowed us to make projections that aided in designing windows for maximized overall efficiency. A gain in power of 2.2x over the PV cells alone was obtained with PV cell coverage of 5%, and a power conversion efficiency as high as 6.8% was obtained with a PV cell coverage of 31%. Balancing the trade-offs between gain and efficiency, the design with the lowest cost per watt attained a power efficiency of 3.8% and a gain of 1.6x.

With the viability of the LSC demonstrated, a weighted Monte-Carlo Ray Tracing program was developed to study the transport of photons and loss mechanisms in the LSC to aid in design optimization. The program imports measured absorption/emission spectra of an organic luminescent dye (LR305), the transmission coefficient and refractive index of acrylic as parameters that describe the system. Simulations suggest that for LR305, 8-10cm of luminescent material surrounding the PV cell yields the highest increase in power gain per unit area of LSC added, thereby determining the ideal spacing between PV cells in the panel. The model also predicts that for different PV cell dimensions, there exists an optimum waveguide thickness which efficiently transports photon collected by the waveguide to the PV cell with minimal loss, and maintains an even distribution of photons across the cell surface. For the case of the 12.5 by 1cm rectangular cells used in this work, the calculated waveguide thickness is 3mm. For larger cells, every 1cm increment in PV cell width should be accompanied by a 0.75mm increase in waveguide thickness to preserve peak performance.

In line with the goal of pushing for cost competitive photovoltaics, the last part of this work shifts to the study of colloidal quantum dot solar cells. A combination of low temperature, highly scalable fabrication process and reduced material usage for thin films offers us a means to produce flexible and cheap solar cells. Tagging on to existing work already performed on germanium quantum dot solar cells, additional work was carried out to further characterize the material. The effect of film thickness, nano-particle surface conditions and thermal anneal were investigated. There is evidence to suggest that the quantum dot devices contain high levels of parasitic resistances. Short circuit current densities increase by up to two times with two spin-cast layers compared to four, leading to the conjecture that charge carrier life time is low with high levels of recombination. Annealing to improve carrier mobility produces devices with current densities up to 301µA, a fourfold increase, but output voltages saw a sharp decrease from 0.12V to 0.015V.

In tandem with the work on germanium, experiments on silicon quantum dots were also carried out to investigate their viability for use as photovoltaic devices. The stronger bonds formed by silicon hindered the ligand exchange process. Schottky diodes were made via drop casting and displayed a clear photovoltaic effect albeit with very low current densities. Interestingly, an open circuit voltage was observed even when not under illumination and further investigations are ongoing.