Engineering Commons^™

Improving Solar Cell Performance Using Cdse/Zns Core/Shell Quantum Dots In A Spectral Conversion System, Buddy Bump

Materials Engineering

Solar cells have been found to absorb light more efficiently and effectively when the energy of incoming photons matches the electronic band gap of the solar cell. Spectral conversion of light from UV to lower energy wavelengths can improve solar cell efficiency an estimated 14.5%. Cadmium Selenium/Zinc Sulfide Core/Shell quantum dots have been successfully embedded in PDMS silicone elastomer. Using a Keithley 2400 Electrometer with Labview software, voltage and current characteristics have been recorded in steps of 10 mV with a wait time of 250 ms on a commercially available solar cell using an artificial solar spectrum created by a …

Morphology And Roughness Of Al2o3 On Ferritic Stainless Steel Foil For Diesel Catalytic Converter Applications, Megan Butala

Materials Engineering

The improved thermal properties of metal-substrate catalytic converters enable effective catalysis sooner after ignition than traditional ceramic monoliths, resulting in less harmful emissions. ACAT Global, a manufacturer of stainless steel catalytic converters, uses ferritic stainless steel substrates for low temperature catalytic converters for diesel automobiles. Production begins with an oxidizing heat treatment to increase surface roughness. The success of the second production step, the application of catalyst-containing ceramic slurry (washcoat), depends on the surface roughness that results from oxidation. Formation of the primary oxide of interest, alumina (Al₂O₃), is controlled by the stainless steel foil composition, …

Discontinuous Grain Boundaries Of Forged René 41, Steven Crump

Materials Engineering

Forged components must pass a grain size specification (grain size, distribution) for acceptance in an application. The varying amounts of plastic deformation during forging can lead to abnormally large recrystallized grain sizes in certain regions of the part, which will not pass specification. The question exists whether these abnormally coarse grains are truly comprised of poly crystalline fine grains with grain boundaries resistant to etching techniques. To investigate this abnormal grain size effect, a cross section of a forged René 41 nickel-based superalloy aircraft engine ring was cut and sectioned into six segments. Those segments were then prepared for microstructural …

Analyzing The Corrosion Resistance Of Ni-Shield 200 Coatings At Different Temperatures When Exposed To Sulphuric Acid, Alex Hussinger

Materials Engineering

Six steel samples each were twin wire arc sprayed with Hastelloy C-276 or Nickel-Shield 200 coatings approximately 0.020″ thick. These samples were then cut into 3″ by 3″ squares. A 2″ diamond grit hole saw was used to abrade and polish to a smooth surface a ring in the middle in order to get an O-ring mechanical seal. The samples were then weighed and loaded into a jig that started from the bottom up with a stainless steel plate, then the sample, then a Viton O-ring, a ¾″ thick glass plate with a 1 3/4″ hole cut in it, another …

Al2O3 Oxide Morphology For Two Fe-Cr-Al Stainless Steel Foils Used In Gasoline Engine Catalytic Converters, Jennifer Suiter

Materials Engineering

Corrugated 0.05 in thick strips of Fe-Cr-Al ferritic stainless steel samples with 4% and 6% aluminum were heat treated, and the resulting Al₂O₃ oxide was analyzed using SEM imaging. Three heat treatment cycles were carried out for each sample. The heat treatments were based on future metal-substrate catalytic converter processing prior to applying the washcoat Each heat treatment started with a 90 minute ramp from room temperature to 538°C and a 32.5 minute ramp from 538°C to 899°C. The three different dwell periods at 899°C were 4 hours, 6 hours, and taking a sample out every hour …

The Mitigation Of Eutrophication Using Microporous Polymer Membranes To Control Algae Growth, Christopher R. Riley

Materials Engineering

A system was designed to mitigate the accelerated process of anthropogenic eutrophication. This system aimed to contain Chlorella Vulgaris microalgae cells within an enclosed polymer membrane pouch while allowing for water and nutrients to diffuse through the pouch. As a test model, a 10 gallon aquarium was partitioned into three sections using polycarbonate membranes with 1 micron pore diameters. Each section was then gradually filled with a deionized water and Bristol solution recommended for microalgae growth. Phosphate and nitrate were added to Section A of the aquarium and allowed to diffuse throughout the tank. A water pump was used to …

Distributed And Centralized Iterative Detection Of Self-Encoded Spread Spectrum In Multi-Channel Communication, Liang Chi, Won Mee Jang, Lim Nguyen

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

We propose self-encoded spread spectrum with two different iterative detection methods in multi-channel communication. The centralized iterative detection outperforms the iterative detection distributed over multiple channels. The results show that self-encoded spread spectrum with the centralized iterative detection is an excellent candidate for cognitive radio network.

Finite Element Analysis Of The Implantation Of A Self-Expanding Stent: Impact Of Lesion Calcification, Shijia Zhao, Linxia Gu, Stacey R. Froemming

Department of Mechanical and Materials Engineering: Faculty Publications

In this work, the deployment of a self-expanding stent in a stenosed artery was evaluated through finite element analysis. The three-layered structure of the artery and their material properties were measured and implemented in our computational models. The instant outcomes, including lumen gain, tissue prolapse, and stress distribution, were quantified, and the effect of plaque calcification was evaluated. Results showed that the peak wall stress occurred on the media layer regardless of plaque calcification. The calcified plaque mitigated the tissue prolapse and arterial wall stresses in general, compared with the soft plaque. However, the lesion calcification led to a more …

Method Of Moment Analysis Of Partially Shielded Chiral Bodies Of Revolution, Khaja Qutubuddin

Electrical Engineering and Computer Science - Dissertations

A chiral body of revolution (BOR) which is partially covered by a thin conducting shield is analyzed using the method of moments (MOM). The axisymmetric system is excited by a plane wave. The total internal fields and the far scattered fields are computed. The problem is solved using the surface equivalence principle. The scattered fields outside the structure are assumed to be produced by an equivalent magnetic surface current that exists on the unshielded part of the BOR surface and an external equivalent electric surface current that exists over all of the BOR surface . These two currents are assumed …

A Knowledge-Based Clinical Toxicology Consultant For Diagnosing Single Exposures, Joel D. Schipper, Douglas D. Dankel Ii, A. Antonio Arroyo, Jay L. Schauben

Publications

Objective: Every year, toxic exposures kill twelve hundred Americans. To aid in the timely diagnosis and treatment of such exposures, this research investigates the feasibility of a knowledge-based system capable of generating differential diagnoses for human exposures involving unknown toxins.

Methods: Data mining techniques automatically extract prior probabilities and likelihood ratios from a database managed by the Florida Poison Information Center. Using observed clinical effects, the trained system produces a ranked list of plausible toxic exposures. The resulting system was evaluated using 30,152 single exposure cases. In addition, the effects of two filters for refining diagnosis based on …

How To Build A Nixie Clock, Shepherd Darquea

Physics

No abstract provided.

Wireless Ad Hoc Networks For Mobile Devices Via High Frequency Sound Waves, Yashar Bahman

Computer Engineering

The purpose of this research it to give mobile phones the ability to create a cross-platfor wireless ad-hoc network. To accomplish this the phone’s speaker/microphone will be treated as a modulator/demodulator (or modem for short). The idea is that the phone will generate sine waves at various frequencies to output them on the speaker on one end and also record audio with the microphone to analyze and decode it into data on the other.

Once complete, these functionalities will all be rolled up into one easy to use library named Wave, which can be used to send data back and …

An Empirical Study Of Particulate Matter Exposure For Passengers Waiting At Bus Stop Shelters In Portland, Oregon, Usa, Adam Moore, Miguel A. Figliozzi, Christopher Michael Monsere

Civil and Environmental Engineering Faculty Publications and Presentations

Current guidelines for the location and design of bus stops do not take into account air quality or exposure considerations for waiting passengers. This paper compares the exposure of transit riders waiting at three-sided bus stop shelters that either: 1) face roadway traffic, or 2) face away from roadway traffic. Shelters were instrumented with devices to monitor particulate matter concentration inside and outside the shelter, wind speed and direction, and vehicle counts. Data were collected at three shelters during both the morning and afternoon peak periods. Bus shelter orientation is found to have a significant effect on the concentration of …

Reliable Software Updates For On-Orbit Cubesat Satellites, Sean Fitzsimmons

Master's Theses

CubeSat satellites have redefined the standard solution for conducting missions in space due to their unique form factor and cost. The harsh environment of space necessitates examining features that improve satellite robustness and ultimately extend lifetime, which is typical and vital for mission success. The CubeSat development team at Cal Poly, PolySat, has recently redefined its standard avionics platform to support more complex mission capabilities with this robustness in mind. A significant addition was the integration of the Linux operating system, which provides the flexibility to develop much more elaborate protection mechanisms within software, such as support for remote on-orbit …

Compulsator Design For Electromagnetic Railgun System, Bryan Bennett

Electrical Engineering

This project designed, fabricated, and partially tested a compensated pulsed alternator (compulsator) to power an electromagnetic rail gun (EMRG) in a multidisciplinary team. The EMRG team includes two master’s AERO students, two senior EE students, and three senior ME students. Design of the compulsator began with research through conference and research papers. This design was changed throughout the project as system analysis and component testing exposed unforeseen system limitations. While original specifications were not met, all fabricated components but one, the stator, were completed using Cal Poly’s facilities and the project’s limited available budget. Experimental verification of calculations and system …

Hearst Hydroelectric Generation Facility, Anthony Schifano, Richard Wright, Nick Buchanan, Corey Nakai, Joshua Rutheiser

Electrical Engineering

This project proposes a power plant design that provides a supplemental source of electricity for appliances, machinery, and lighting at Hearst Castle and Ranch. The design concept includes a turbine-generator combination to convert kinetic and gravitational potential energy from the existing water distribution system to electrical energy: also known as a hydroelectric plant. The electrical distribution system from the plant to the local grid takes advantage of power flow techniques utilized in current research and industry.

Rfid Check-In System For Safe Routes To School At Hawthorne Elementary, Paul Banel

Electrical Engineering

The system uses a low frequency Radio Frequency Identification (RFID) reader and passive RFID tags to help the Safe Routes to School program at Hawthorne Elementary in San Luis Obispo track the number of children who participate in the program. Children will carry passive RFID tags and scan them at the reader each morning that they walk or bike to school. The system tracks the total number of students that walk and bike each day, as well as the number of times each individual child participates over the course of many days. The Safe Routes program hopes to use this …

Printed Electroluminescent Display, Christopher (Chris) James Nixon, Veronica Kopp

Electrical Engineering

Electroluminescent displays are part of an emerging technology known as printed electronics. Most identify printed electronics with purely electronic purposes such as the Radio frequency identification (RFID). Now the electronics and graphic communication industries have come together to create of new forms of products that interact with customers. Flexible, electronic circuits use functional inks and traditional printing methods such as screen printing, gravure, and inkjet. Printed electronics are perfect for low performance applications, such as displays, labels, clothing and batteries. This paper focuses on creating an interactive electroluminescent (EL) display. In selling a product, displays are important because most customers …

Hardware And Software Study Of Active Noise Cancellation, Riggi Aquino, Jacob Lincoln

Electrical Engineering

Noise cancellation involves removing an unwanted noise while keeping the source sound. The source sound may consist of speech, music played from a device such as an iPod or a computer, or no sound at all. The objective of this project is to study the process of noise cancellation both as hardware and as software. The hardware will consist of building a noise cancelling circuit that uses headphones as an output, a microphone to pick up the noise to be cancelled and, if desired, a source sound. The software portion of the experiment will use MATLAB to simulate the hardware …

Retrofitting A Car Alternator For Low-Speed Power Generation, Yuri Carrillo

Electrical Engineering

This report presents the analysis and methods taken to appropriately modify a car alternator to operate as a low speed generator for wind or hydro power generation. A Toyota car alternator taken from a junkyard is characterized via an Open-Circuit test to evaluate its operating specifications. The car alternator is also measured to determine its physical dimensions. The acquired values are used with the generated voltage equation to determine the machine’s unknown rotor values— the product of the rotor winding factor and the number of rotor windings (kfNf). Using the generated voltage equation with the determined machine parameters, the number …

High Efficiency Audio Amplifier, Grant Moore

Electrical Engineering

This project combines the advantages of high efficiency of power electronics with the existing high fidelity of audio amplifiers. The result will be functionally equivalent to existing amplifiers but will use considerably less energy. A complete system was designed, simulated, built and tested in a period of three quarters. The end result is an amplifier that functions, but would not be suitable for commercial marketing. Suggestions to improve the performance are provided.

An Overview Of Binary Arithmetic Architectures & Their Implementation In Dsp Systems, Joseph Waddell

Electrical Engineering

This project gives looks at different binary adder and multiplier architectures and how they are implemented in a DSP system as a digital filter. Testing is performed in the Digilent Nexys2 FPA board and filters are implemented using various realizations including normal direct form I and cascade direct forms I and II. Signal filtering is performed in real time at various frequencies and results are provided on an oscilloscope and with a stereo speaker.

"Auto-Tuned" Stereo, Daniel Montes

Electrical Engineering

The purpose of this project is to determine the capability of introducing delay and gain to audio signals to synthesize a “tuned” experience. The project uses audio operational amplifiers, field effect transistors, a class D amplifier, microphones, speakers, a 32-bit microcontroller for design and testing. When implementing the MOSFET into the all pass filter, the phase delay occurs by varying the transistor resulted in minimal change in phase. MOSFETs are used as variable resistors to vary the phase change and gain. By modifying the gain the synthesized distance from each speaker can be adjusted. Varying the phase change provides the …

Lyfi, Kianoosh Salami, Justin Cotton, Elush Shirazpour

Electrical Engineering

This paper will cover the steps necessary to design, build, and manage networkable smart light switches over WiFi via a mobile application. It contains a microcontroller running a real time operating system, a WiFi module, a Java server with SQLite databasing, and a mobile phone application.

LyFi is designed to turn on/off and dim household lights while only requiring the same installation procedure as a less capable dimmer switch. Once installed and connected to a network, LyFi will self-discover and configure. The server automatically propogates a database of nodes where any mobile device running an application can receive an updated …

Independent Moisture-Sensitive Automatic Watering System, Jessica Sherbon

Electrical Engineering

With the availability of home improvement supplies, plant owners can quickly and easily set up an automatic system that waters their gardens based on a specified schedule. However, most of these systems require an electric outlet or water faucet making them unusable in locations where installed water and power lines do not exist, such as apartment balconies. This project defines a small-scale automated watering system that runs independently of installed water and power lines. The system takes water from a reservoir, such as a tank or bucket, and supplies that water to individual plants via a drip system. The design …

Inductive Metal Identification, Paul Maggi

Electrical Engineering

This project focuses on creating a device to differentiate between various types of metals via magnetic induction. Magnetic induction is used because it is both non-optical and non-contact. It achieves this by generating a varying magnetic field, which induces eddy currents in the metal. These eddy currents produce small disturbances in the surrounding magnetic field, which can be sensed with Hall Effect Sensors (HES). The primary challenge in this project was generating a sufficiently strong magnetic field to detectable disturbances. In order to achieve better results, a stronger magnetic field must be used as well as more sensitive Hall Effect …

Gamecube To Nintendo 64 Controller Converter, Andrew Jia-Haur Lee

Electrical Engineering

No abstract provided.

Portable Solar Powered Charging Station, Jordan Bonner

Electrical Engineering

The portable solar powered charging station uses a solar powered mat that can be folded for portability. The device has the ability to charge small electronics during both day and night. When sunlight is available, the charger charges two C batteries in series and at the same time it charges any electronic device that can be connected via USB or cigarette lighter. At night the charger will charge the same electronic devices from the onboard batteries. The charging station must be able to interface with electronic devices using USB and a car cigarette lighter to charge the device’s battery.

Digital Guitar Effects Unit And Amplifier, Kevin Salvador

Electrical Engineering

This report outlines the design and implementation of a digital guitar effects unit and amplifier. The main portion of this project consisted of the digital equalizer and effects. Several commercial equalizers were researched in order to decide the typical frequency bands and average amount of bands total. Eventually 8 bands were selected. A range of approximately 20Hz-3kHz was chosen based on test data of guitar signals. Popular effects that were incorporated in this project include Distortion, Echo, Reverb, Chorus and Flanger. The digital processor chosen was a Texas Instruments c6713 floating point processor. Designs for the various filters were done …

3d Digital Modeling For Urban Design + Planning, Emmanuel Velazco

City and Regional Planning

Cities throughout the country face a number of challenges in dealing with the changing development needs of the 21st century. In urban planning, the fusion of social, environmental, political, economic, and functional considerations are required. Today, local, state, and federal governments are experiencing an economic downturn, making resources scarce to plan for smarter development, attain greater public interest, and economic revival.

The primary objective of this project is to provide innovative solutions in city and regional planning using software applications, such as Google SketchUp, that enable assessment of various urban design projects. A second objective was to create a 3D …