Matching Items (50)
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- Creators: Barrett, The Honors College
- Member of: Theses and Dissertations
Description
There is an interest in citizen scientist networks such as CoCoRaHS to develop an air temperature sensor with a solar shield that is both extremely low cost and user friendly for use in widespread data collection in order to analyze urban microclimates. This paper outlines work done to develop a low cost micrometeorology instrument to fulfill the design requirements set by CoCoRaHS. While the first two revisions of this technology had significant changes in development, a third revision was created as a proof of concept that low cost temperature sensors could be used in an array to accurately measure air temperature without solar radiation interference. Another technology, described as revision four, called the iButton was also evaluated and displayed promising ability to log temperatures, but costs too much for the ultra-low cost design goal. Additionally, work was done to design a radiation shield that will be prototyped and tested alongside commercial radiation shields. This controlled experiment will also include further evaluation of the iButton and the next revision of a custom microclimate temperature sensing unit to determine the best option for widespread field testing.
ContributorsMarshall, Travis Keith (Author) / Jordan, Shawn (Thesis director) / Ruddell, Benjamin (Committee member) / Barrett, The Honors College (Contributor) / Department of Engineering (Contributor)
Created2014-05
Description
Lighting Audio is a team of senior electrical engineering students at the Arizona State University mentored by Director Emeritus Professor Ronald Roedel and 2nd Committee Member George Karady attempting to prove the feasibility of a consumer grade plasma arc speaker. The plasma arc speaker is a project that explores the use of high voltage arcs to produce audible sound amplification. The goal of the project is to prove feasibility that a consumer grade plasma arc speaker could exist in the marketplace. The inherent challenge was producing audio amplification that could compete with current loudspeakers all while ensuring user safety from the hazards of high voltage and current shock, electromagnetic damage, and ozone from the plasma arc. The project has thus far covered the process of design conception to realization of a prototype device. The operation of the plasma arc speaker is based on the high voltage plasma arc created between two electrodes. The plasma arc rapidly heats and cools the surrounding air creating changes in air pressure which vibrate the air. These pockets of pressurized air are heard as sound. The circuit incorporates a flyback transformer responsible for creating the high voltage necessary for arcing.
ContributorsNandan, Rahul S (Author) / Roedel, Ronald (Thesis director) / Huffman, James (Committee member) / Electrical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2014-05
Description
Lighting Audio is a team of senior electrical engineering students at the Arizona State University mentored by Director Emeritus Professor Ronald Roedel and 2nd Committee Member George Karady attempting to prove the feasibility of a consumer grade plasma arc speaker. The plasma arc speaker is a project that explores the use of high voltage arcs to produce audible sound amplification. The goal of the project is to prove feasibility that a consumer grade plasma arc speaker could exist in the marketplace. The inherent challenge was producing audio amplification that could compete with current loudspeakers all while ensuring user safety from the hazards of high voltage and current shock, electromagnetic damage, and ozone from the plasma arc. The project has thus far covered the process of design conception to realization of a prototype device. The operation of the plasma arc speaker is based on the high voltage plasma arc created between two electrodes. The plasma arc rapidly heats and cools the surrounding air creating changes in air pressure which vibrate the air. These pockets of pressurized air are heard as sound. The circuit incorporates a flyback transformer responsible for creating the high voltage necessary for arcing.
ContributorsNandan, Rahul S (Author) / Roedel, Ronald (Thesis director) / Huffman, James (Committee member) / Barrett, The Honors College (Contributor) / Electrical Engineering Program (Contributor)
Created2014-05
Description
This paper reviews several current designs of Cube Satellite (CubeSat) Electrical Power Systems (EPS) based on Silicon FET technologies and their current deficiencies, such as radiation-incurred defects and switching power losses. A strategy to fix these is proposed by the way of using Gallium Nitride (GaN) High Electron-Mobility Transistors (HEMTs) as switching devices within Buck/Boost Converters and other regulators. This work summarizes the EPS designs of several CubeSat missions, classifies them, and outlines their efficiency. An in-depth example of an EPS is also given, explaining the process in which these systems are designed. Areas of deficiency are explained along with reasoning as to why GaN can mitigate these losses, including its wide bandgap properties such as high RDS(on) and High Breakdown Voltage. Special design considerations must be kept in mind when using GaN HEMTs in this application and an example of a CubeSat using GaN HEMTs is mentioned. Finally, challenges ahead for GaN are explored including manufacturing considerations and long-term reliability.
ContributorsWilloughby, Alexander George (Author) / Kitchen, Jennifer (Thesis director) / Zhao, Yuji (Committee member) / Electrical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
We designed and constructed a cryostat setup for MKID detectors. The goal for the cryostat is to have four stages: 40K, 4K, 1K and 250mK. Prior to the start of my thesis, the cryostat was reaching 70K and 9K on the first and second stages respectively. During the first semester of my thesis I worked on getting the second stage to reach below 4K such that it would be cold enough to add a sorption fridge to reach 250mK. Various parts were machined for the cryostat and some tweaks were made to existing pieces. The largest changes were we thinned our stainless steel supports from 2mm to 10mil and we added roughly 6-10 layers of multi-layer insulation to the first and second stages. Our result was that we now reach temperatures of 36K and 2.6K on the first and second stages respectively. Next we added the sorption fridge to the 4K stage by having the 4K stage remachined to allow the sorption fridge to be mounted to the stage. Then I designed a final, two stage, setup for the 1K and 250mK stages that has maximum capabilities of housing a six inch wafer for testing. The design was sent to a machinist, but the parts were unfinished by the end of my thesis, so the parts and stage were not tested. Once the cryostat was fully tested and proven to reach the necessary temperatures, preliminary testing was done on a Microwave Kinetic Inductance Detector (MKID) provided by Stanford. Data was collected on the resonance and quality factor as they shifted with final stage temperature (5K to 285mK) and with input power (60dB to 15dB). The data was analyzed and the results agreed within expectations, as the resonant frequency and quality factor shifted down with increased temperature on the MKID. Finally, a noise characterization setup was designed to test the noise of devices, but was not fully implemented.
ContributorsAbers, Paul (Author) / Mauskopf, Phil (Thesis director) / Groppi, Chris (Committee member) / Department of Physics (Contributor) / School of Earth and Space Exploration (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
This is a lectures series on photovoltaics. As the need for electrical energy rises, mankind has struggled to meet its need in a reliable lasting way. Throughout this struggle, solar energy has come to the foreground as a complete solution. However, it has many drawbacks and needs a lot of development. In addition, the general public is unaware of how solar energy works, how it is made, and how it stands economically. This series of lectures answering those three questions. After two years doing photovoltaic research, and an undergraduate degree in Electrical Engineering, enough expertise has been acquired present on at a late high-school to early college level. Education is key to improving the popularity of using solar energy and the popularity of investing in photovoltaic research. Solar energy is a viable option to satisfy our energy crisis because the materials it requires can quickly be acquired, and there is enough of material to provide a global solution. In addition, the amount of solar energy that hits the surface of the earth in a day is orders of magnitude more than the amount of energy we require. The main goal of this project is to have an effective accessible tool to teach people about solar. Thus, the lectured will be posted on pveducation.com, YouTube, the Barrett repository, and the QUSST website. The content was acquired in four ways. The first way is reading up on the current papers and journals describing the new developments in photovoltaics. The second part is getting in contact with Stuart Bowden and Bill Daukser at Arizona State University's Solar Power Lab as well as the other faculty associated with the Solar Power Lab. There is quite a bit of novel research going on at their lab, as well as a student run pilot line that is actively building solar cells. The third way is reading about solar device physics using device physics textbooks and the PVEducation website made by Stuart Bowden. The forth way is going into ASU's solar power lab.
ContributorsLeBeau, Edward (Author) / Goryll, Michael (Thesis director) / Bowden, Stuart (Committee member) / Dauksher, William (Committee member) / Barrett, The Honors College (Contributor)
Created2017-05
Description
As global population and demand for electrical power increase, humanity is faced with the growing challenge of harnessing and distributing enough energy to sustain the developing world. Currently, fossil fuels (coal
atural gas) are our main sources of electricity. However, their cost is increasing, they are nonrenewable, and they are very harmful to the environment. Thus, capacity expansion in the renewable energy sector must be realized to offset higher energy demand and reduce dependence on fossil fuels. Solar energy represents a practical solution, as installed global solar capacity has been increasing exponentially over the past 2 decades. However, even with government incentives, solar energy price ($/kWh) continues to be highly dependent on political climate and raw material (silicon and silver) cost. To realistically and cost effectively meet the projected expansions within the solar industry, silver must be replaced with less costly and more abundant metals (such as copper) in the front-grid metallization process of photovoltaic cells. Copper, while offering both higher achievable efficiencies and a raw material cost nearly 100 times cheaper than silver, has inherent disadvantages. Specifically, copper diffuses rapidly into the silicon substrate, requires more complex and error-prone processing steps, and tends to have less adhesive strength, reducing panel robustness. In this study, nickel deposition via sputtering was analyzed, as well as overall potential of nickel as a seed layer for copper plating, which also provides a barrier layer to copper diffusion in silicon. Thermally-formed nickel silicide also reduces contact resistivity, increasing cell efficiency. It was found that at 400 \u00B0C, ideal nickel silicide formation occurred. By computer modeling, contact resistivity was found to have a significant impact on cell efficiency (up to 1.8%). Finally, sputtering proved useful to analyze nickel silicide formation, but costs and time requirements prevent it from being a practical industrial-scale metallization method.
atural gas) are our main sources of electricity. However, their cost is increasing, they are nonrenewable, and they are very harmful to the environment. Thus, capacity expansion in the renewable energy sector must be realized to offset higher energy demand and reduce dependence on fossil fuels. Solar energy represents a practical solution, as installed global solar capacity has been increasing exponentially over the past 2 decades. However, even with government incentives, solar energy price ($/kWh) continues to be highly dependent on political climate and raw material (silicon and silver) cost. To realistically and cost effectively meet the projected expansions within the solar industry, silver must be replaced with less costly and more abundant metals (such as copper) in the front-grid metallization process of photovoltaic cells. Copper, while offering both higher achievable efficiencies and a raw material cost nearly 100 times cheaper than silver, has inherent disadvantages. Specifically, copper diffuses rapidly into the silicon substrate, requires more complex and error-prone processing steps, and tends to have less adhesive strength, reducing panel robustness. In this study, nickel deposition via sputtering was analyzed, as well as overall potential of nickel as a seed layer for copper plating, which also provides a barrier layer to copper diffusion in silicon. Thermally-formed nickel silicide also reduces contact resistivity, increasing cell efficiency. It was found that at 400 \u00B0C, ideal nickel silicide formation occurred. By computer modeling, contact resistivity was found to have a significant impact on cell efficiency (up to 1.8%). Finally, sputtering proved useful to analyze nickel silicide formation, but costs and time requirements prevent it from being a practical industrial-scale metallization method.
ContributorsBliss, Lyle Brewster (Author) / Bowden, Stuart (Thesis director) / Karas, Joseph (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
This is a lectures series on photovoltaics. As the need for electrical energy rises, mankind has struggled to meet its need in a reliable lasting way. Throughout this struggle, solar energy has come to the foreground as a complete solution. However, it has many drawbacks and needs a lot of development. In addition, the general public is unaware of how solar energy works, how it is made, and how it stands economically. This series of lectures answering those three questions.
ContributorsLeBeau, Edward Sanroma (Author) / Goryll, Michael (Thesis director) / Bowden, Stuart (Committee member) / Dauksher, Bill (Committee member) / Electrical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
With the progression of different industries moving away from employing secretaries for business professionals and professors, there exists a void in the area of personal assistance. This problem has existing solutions readily available to replace this service, i.e. secretary or personal assistant, tend to range from expensive and useful to inexpensive and not efficient. This leaves a low cost niche into the market of a virtual office assistant or manager to display messages and to help direct people in obtaining contact information. The development of a low cost solution revolves around the software needed to solve the various problems an accessible and user friendly Virtual Interface in which the owner of the Virtual Office Manager/Assistant can communicate to colleagues who are at standby outside of the owner's office and vice versa. This interface will be allowing the owner to describe the status pertaining to their absence or any other message sent to the interface. For example, the status of the owner's work commute can be described with a simple "Running Late" phrase or a message like "Busy come back in 10 minutes". In addition, any individual with an interest to these entries will have the opportunity to respond back because the device will provide contact information. When idle, the device will show supplemental information such as the owner's calendar and name. The scope of this will be the development and testing of solutions to achieve these goals.
ContributorsOffenberger, Spencer Eliot (Author) / Kozicki, Michael (Thesis director) / Goryll, Michael (Committee member) / Electrical Engineering Program (Contributor) / Computer Science and Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Imaging using electric fields could provide a cheaper, safer, and easier alternative to the standard methods used for imaging. The viability of electric field imaging at very low frequencies using D-dot sensors has already been investigated and proven. The new goal is to determine if imaging is viable at high frequencies. In order to accomplish this, the operational amplifiers used in the very low frequency imaging test set up must be replaced with ones that have higher bandwidth. The trade-off of using these amplifiers is that they have a typical higher input leakage current on the order of 100 compared to the standard. Using a modified circuit design technique that reduces input leakage current of the operational amplifiers used in the imaging test setup, a printed circuit board with D-dot sensors is fabricated to identify the frequency limitations of electric field imaging. Data is collected at both low and high frequencies as well as low peak voltage. The data is then analyzed to determine the range in intensity of electric field and frequency that this circuit low-leakage design can accurately detect a signal. Data is also collected using another printed circuit board that uses the standard circuit design technique. The data taken from the different boards is compared to identify if the modified circuit design technique allows for higher sensitivity imaging. In conclusion, this research supports that using low-leakage design techniques can allow for signal detection comparable to that of the standard circuit design. The low-leakage design allowed for sensitivity within a factor two to that of the standard design. Although testing at higher frequencies was limited, signal detection for the low-leakage design was reliable up until 97 kHz, but further experimentation is needed to determine the upper frequency limits.
ContributorsLin, Richard (Co-author) / Angell, Tyler (Co-author) / Allee, David (Thesis director) / Chung, Hugh (Committee member) / Electrical Engineering Program (Contributor) / W. P. Carey School of Business (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12