Engineering Commons^™

Digitally Controlled Zero-Voltage-Switching Quasi-Resonant Buck Converter, Brian R. Luc

Master's Theses

ABSTRACT

Digitally-Controlled Two-Phase Zero-Voltage-Switching Quasi-Resonant Buck Converter

Brian Luc

This thesis entails the design, construction, and performance analysis of a digitally-controlled two-phase Zero-Voltage Switching Quasi-Resonant (ZVS-QR) buck converter. The converter is aimed to address the issues associated with powering CPUs operating at lower voltage and high current. To evaluate its performance, the Two-Phase ZVS-QR buck converter is compared against a traditional Two-Phase buck converter. The design procedure required to implement both converters through utilizing the characterization curve and formulas derived from their circuit configurations will be presented. Computer simulation of the Two-Phase ZVS-QR buck converter is provided to exhibit its …

Aerospike Rocket Motor Structural Webbing, Andrew Brock

Master's Theses

A labscale hybrid rocket motor test stand has been developed for research at Cal Poly. The primary focus of research using this rig has been the development of regenerative cooling techniques using nitrous oxide as coolant and oxidizer, as well as validation of technologies relating to the annular aerospike nozzle. In order to prevent undesirable deflection of the cantilevered spike, a structural stiffening web, referred to as “The Spider,” is proposed. The Spider resembles a three-spoked wheel, with the aerospike held by the inner hub and the chamber walls abutting the outer radius.

The Spider, placed upstream of the nozzle, …

A Low-Cost Loop Measurement Tool For Dc-Dc Converters, Shouee B. Lin

Master's Theses

Loop measurements are very important in evaluating dynamic performance of DC-DC converters. In this thesis, a small loop measurement tool as a low-cost alternative to a network analyzer is proposed. The tool is particularly useful when a network analyzer is not always available for use, for example when engineers are working on-site with customers or when a network analyzer is not affordable due to their relatively high cost. The design, simulation, and hardware implementation of the inexpensive loop measurement tool will be presented in this thesis. Results from computer simulation and hardware prototype demonstrate the ability of the proposed tool …

Evapotranspiration From Natural Vegetation In The Central Valley Of California: Monthly Grass Reference-Based Vegetation Coefficients And The Dual Crop Coefficient Approach, Daniel J. Howes, Phyllis Fox, Paul H. Hutton

BioResource and Agricultural Engineering

Restoration activities in the Central Valley of California and elsewhere require accurate evapotranspiration information, which can then be used for a wide variety of surface and subsurface hydrologic evaluations. However, directly measuring evapotranspiration can be difficult or impossible depending on the evaluation’s time frame. Transferability of measured evapotranspiration in time and space is also necessary but typically requires a weather-based reference. For nonagricultural vegetation, there is at present time no standard reference, which makes the evaluation of a variety of vegetation types from different sources difficult and time-consuming. This paper examines several methods used to estimate evapotranspiration from native vegetation, …

Aerodynamic Testing And Development Of Sunswift Eve, Simon Ambrose, Graham Doig

Aerospace Engineering

The current understanding of the aerodynamic performance of Sunswift’s solar-electric race car eVe is limited, despite the design and manufacture of the vehicle in 2012-13. This paper describes an investigation into the aerodynamic behaviour of the vehicle and details the successive design and development of drag minimisation strategies. A study of the ex­ternal airflow around the vehicle was undertaken through a computational fluid dynamics analysis, with validation offered through the results of real-world track testing. Particular reference is made to the Sunswift team’s successful long-range electric vehicle land speed record attempt on 23 July 2014. A predicted 10% reduction in …

Enhanced Presentation Of Tomographic Data, Carmen Watts Clayton, Bernice E. Mills, George Buffleben, Thien Vu-Nguyen

STAR Program Research Presentations

Solid materials can now be viewed non-destructively with x-rays by tomography; a technique for taking many 2D images of an object at many angles and reconstructing the images into a 3D data cube. The data is next rendered into 2D or 3D still images or movies. By nature, x-ray tomography yields a very large amount of data in three dimensions. Effectively displaying this data to an audience is a challenge.

In this work techniques are explored to improve the presentation methods of movies of both 2D and 3D tomographic data for visual appeal and correct perspective. Finding the optimal ways …

Practical Guide For Metergates, Charles M. Burt, Daniel J. Howes

BioResource and Agricultural Engineering

This document contains brief instructions on the use of special round canal gates called “metergates” for flow measurement.

Large Dynamic Range Amplifier Plus Adc, Ted Hsueh

Electrical Engineering

Nerve and muscle signal sampling proves difficult because of the large difference in magnitudes. Muscle signals loom a hundred or even a thousand times bigger and can hide the nerve signals. The Large Dynamic Range Amplifier plus Analog to Digital Converter (ADC) allows one device to retrieve both muscle and nerve signal information. The device has two parts: the ability to take high-resolution data from tenths of microvolts to several millivolts and filter out environmental noise, such as 60 Hz of electrical power lines or electro galvanic signals. This gives the ability to read muscle and nerve signals using one …

Boost Battery, Samuel Rauch, Alvin Ng, Lacy Sigman

Electrical Engineering

In modern times, the problem of a depleted battery confronts us too often. Whether it appears with a smartphone or with any other electronic device, the situation frustrates all consumers. This project designs and constructs a compact portable battery charger that charges through kinetic energy. Thus, one can perform everyday activities, such as walking or running, and charge up a backup battery with no extra effort or time. Additionally, an attachable band harvests thermal energy to maximize the amount of clean power generated. Energy harvesting from kinetic motion and thermal differences provide users with power when no actual power suppliers …

Compact Deployable Antenna For Cubesat Units, Sarah Bolton, Dominic Doty, Peter Rivera

Mechanical Engineering

CubeSats are an appealing platform for space exploration due to their low build and launch costs. Due to their small size, communication rates are often severely limited, preventing missions beyond low earth orbit. A low cost, high gain, high frequency antenna is needed to extend the capabilities of CubeSats.

The goal of the project was to design and build an axisymmetric parabolic antenna that could be deployed from a 10cm x 10cm x 15cm (1.5U) volume and operate at Ka band frequencies. The design selected consisted of an expanding perimeter truss supporting a tensioned mesh reflector. The perimeter truss was …

Lightweight Silver Ink Printed Circular Ring Microstrip Patch Antenna For Wlan Applications, Bobak Beheshti

Electrical Engineering

No abstract provided.

Torque Testing System: Flowserve Corporation, Taylor Catlin, David Reese, Bodin Rojanachaichanin, Kyle Stangland

Mechanical Engineering

Flowserve Corporation provides products and customer support to companies in the process industry for the design, testing, and manufacturing of mechanical seals. This includes, but is not limited to, companies concerned with power generation, fossil fuels, water resources, and chemical processing. In industries where fluid transportation is leveraged, mechanical seals have been utilized in pumps to increase performance. A mechanical seal is a design feature in pumps that seal the impeller housing and allow for little to no leakage. This technology is cutting edge and a considerable amount of research pertaining to the advantageous effects of specialized surface features is …

Center Pivot Sprinkler Distribution Uniformity Impacts On The Spatial Variability Of Evapotranspiration, Daniel Howes, Sean Ellenson, Lucas Hoffmann, Franklin Gaudi

BioResource and Agricultural Engineering

Understanding variable evapotranspiration (ET) throughout a field can help maximize yield on a per-acre basis, as well as assist with proper irrigation scheduling. The results from this study indicate that irrigation system distribution uniformity (DU) has a significant effect on the uniformity of ET during water-stressed periods. The study site involved intensely managed forage (alfalfa and winter grain hay) irrigated by center pivots being supplied with reclaimed water near Palmdale, California. During spring and early summer 2007 the center pivots were operating under deficit irrigation. In 2010, after the installation of reservoirs, water was applied to meet full evapotranspiration (ETc) …

Process Improvements Of Cilantro Harvesting With Ergonomic Considerations, Eric Penningroth, Branden Shimamoto

Industrial and Manufacturing Engineering

The problems presented by Talley Farms to the team were a lower than desired cilantro harvesting capacity and work health pertaining to lower back problems. The project objectives were to address and improve upon both of these objectives. To increase harvesting capacity, a simulation model was created using standard times from time studies. The simulation model helped to compare the different harvesting methods as well as the effect of the utilization of the on-site manager. The throughputs between each of the models were analyzed. To address ergonomic concerns, a work sampling study was conducted and it was determined that kneeling …

Bikeshare Business Model For Cal Poly- San Luis Obispo, Justin Benson, Andrew Neil Gatchalian

Industrial and Manufacturing Engineering

With the increasing admittance of students into colleges and universities across the nation, the need for alternate modes of transportation is becoming more pressing. College and university campuses, as well as small cities, in which there is a college or university, are being overloaded with student cars. In San Luis Obispo specifically, parking on campus as well as downtown can be extremely difficult to find. Traffic is also getting progressively worse, especially at the hour when class begins/ends and student arrive to or leave campus. Financial reasons are yet another deterrent for students at Cal Poly. Parking permits, gas, and …

Effects Of Patient Factors On Implantation Rates In In Vitro Fertilization, Heidi Richardson, Sofia Soto

Industrial and Manufacturing Engineering

The purpose of this report is to evaluate the effects of patient factors and embryo quality on the implantation rate in In Vitro Fertilization (IVF). For this report, statistical methods are used to test the significance of several patient and embryo characteristics on embryo implantation rate. This project is an analysis of data collected from over 36,000 patients.

The analysis concluded several findings. There was enough statistical evidence to conclude that age was significant in regards to implantation rate and FSH levels. As the patient ages, the amount of FSH levels found in their blood increases. A patient with high …

Flow Compressibility Effects Around An Open-Wheel Racing Car, J. Keogh, G. Doig, S. Diasinos

Aerospace Engineering

A numerical investigation has been conducted into the influence of flow compressibility effects around an open-wheeled racing car. A geometry was created to comply with 2012 F1 regulations. Incompressible and compressible CFD simulations were compared-firstly with models which maintained Reynolds number as Mach number increased, and secondly allowing Mach number and Reynolds number to increase together as they would on track. Results demonstrated significant changes to predicted aerodynamic performance even below Mach 0·15. While the full car coefficients differed by a few percent, individual components (particularly the rear wheels and the floor/ diffuser area) showed discrepancies of over 10% at …

On The Interaction Of A Racing Car Front Wing And Exposed Wheel, S. Diasinos, G. Doig, T.J. Barber

Aerospace Engineering

A numerical investigation of generic open-wheel racing car wing and wheel geometry has been conducted, using original sub-scale experimental data for validation. It was determined that there are three main interactions that may occur, identifiable by the path that the main and secondary wing vortices take around the wheel. Interaction ‘A’ occurs when the main and secondary wing vortices both travel outboard of the wheel; interaction ‘B’ is obtained when only the main wing vortex passes inboard of the wheel; while interaction ‘C’ sees both wing vortices travel inboard of the wheel. The different interactions are achieved when geometric changes …

Redesign Of Talley Farm's "Fresh Harvest" Produce Program, Nicole Bordwell, John Rivera, Jared Toboni

Industrial and Manufacturing Engineering

Fresh Harvest, a Central Coast Community Supported Agriculture (CSA) program run by Talley Farms located in Arroyo Grande, CA, has a rapidly growing customer base. They harvest, package, and deliver boxes of fresh quality produce to almost 3000 subscribers. However, Talley Farms’ space for production and processing is limited and at times required for other aspects of business. This results in a problem where Talley Farms current processing system of produce for the Fresh Harvest program is not suitable for the forecasted growing demand. This report addresses the need to prepare for continued significant growth to the demand for Fresh …

Analysis And Improvement Of The Security Building At Pg&E Diablo Canyon Nuclear Power Plant, Alyssa Carter, Natalie Christa, Phuong Anh Pham Dinh

Industrial and Manufacturing Engineering

A new Security building was recently designed and built at the Pacific Gas and Electric (PG&E) Diablo Canyon Power Plant (DCPP).This building’s staff and equipment are responsible for performing routine inspections on all personnel entering the facility in order to prevent security-related incidents from occurring at the nuclear power plant. Similar to airport security procedures, the DCPP security building routine inspections include the use of x-ray machines, metal detectors, and explosive detectors.

The Power Plant periodically experiences pre-planned, preventive maintenance outages, that last 4-6 weeks. During an outage, a power plant reactor is shut down for maintenance, repair, and re-fueling. …

Modernization Of The Walker River Irrigation District Water Gauges, Stuart Styles, Robert C. Bryan, Kenneth C. Spooner

BioResource and Agricultural Engineering

The Irrigation Training and Research Center (ITRC) and Walker River Irrigation District (WRID) collaborated on WRID’s Water Gauge Improvement Project with support from the Bureau of Reclamation, U.S. Department of Interior in Carson City, Nevada. This paper presents a summary of the proposed plan and implementation for improving water gauges in WRID with strategic engineering recommendations for new hardware and control equipment; water management strategies; flow measurement devices; and integration of a new district-wide SCADA system. Field investigations and engineering analyses were carried out by the ITRC in 2009 to inspect existing WRID infrastructure, to review current operational procedures, and …

Rapdb: The Rapid Social Application Deployment Service, Lance Tyler, Matthew Morris

Computer Science and Software Engineering

No abstract provided.

Quickbooks Self-Employed Ios Application, Braden Young

Computer Science and Software Engineering

No abstract provided.

Wirelessly Controlled Smart Outlet, Andrew Godsil, Ariel Dubinsky

Electrical Engineering

Popularity of home automation devices has increased greatly in recent years due to higher affordability and simplicity through smartphone and tablet connectivity. For the purpose of this experiment, we have developed the Smart Outlet: a stand-alone communication unit, used to connect home outlets to the internet. The Smart Outlet controls lighting and simple appliances throughout the home, remotely, using wireless commands from the web. A Google Calendar interface directly controls the outlets’ function by scheduling them with dedicated calendar events. The calendar’s interface can even be accessed from multiple different platforms (i.e. phones, computers, tablets) for the convenience of all …

Transimpedance Amplifier For Polymer Photodiodes, Sheridan Knighton

Electrical Engineering

Dr. Braun’s students in the Polymer Electronics Lab currently have a way to measure the light intensity from their light emitting devices however it consumes an unnecessary amount of space and power. I offer to improve upon the existing transimpedance circuit that Dr. Braun currently uses, reducing the total space occupied by the circuit and the power consumption of the current setup. The transimpedance circuit measures the incidence light intensity from the polymer-based photo detector and outputs an accurate, discrete, and measurable voltage. The current setup however utilizes two 20V wall warts for the positive and negative rails of the …

Microprocessor Management Of Energy Harvesting Buck Boost Converters, Timothy O'Sullivan

Electrical Engineering

No abstract provided.

High Voltage Pulse-Width Generator For The Algae Biofuel Project, Philip Yu, Stephen Leung

Electrical Engineering

This purpose of this project, sponsored by Boeing and advised by Dr. Arakaki and Dr. Taufik, is to build a high voltage pulse width generator that lyses algae cells to harvest the biofuel within. This project uses Emmanuel Loza's thesis on a cascaded high voltage converter with variable control to build a portable pulse width generator with independent control on the peak voltage, pulse width, and frequency. The project focuses on creating a pulse width generator capable of finding the most optimal pulsed electric field to lyse algae. The pulse width module ranges from 10V-80V peak voltage, 60Hz-100 kHz frequency, …

Badge Web Application, Ryan Green

Computer Engineering

This project includes the imagining, design, build, and test of a web application that creates and tracks a user’s progress on completing tasks that an administrator has created for the user. The goal of this project is to have a functioning webpage that is robust and scalable to support many users and many tasks. The application will be developed for use on all modern web browsers, and will have a persistent server to access from any platform. This project was designed to be an exercise in building a modern web application, and as such is written using many different languages, …

Cold Roll Extrusion Machine Redesign Final Design Report, Foja Bains, Bryan Cyr, David Van Schooten

Mechanical Engineering

This report is a comprehensive review of a redesign of subsystems for a Cold Roll Extrusion Machine, a forging operation, for PCC Rollmet. Three subsystems were addressed in this project: A new Loading system, Feed system, and Lubrication system. The Loading system, and support system during developmental design stages, addressed the timely loading process of pipes onto the forging machine. After two quarters of design iteration, the group decided on a lever arm, hydraulic actuated, loading design. In the final quarter of the project, a quarter scale model of this lever arm was constructed to prove the concept of the …

Farmbot, James Cruz, Scott Herrington, Bryan Rodriguez

Mechanical Engineering

The purpose of this project was to develop the hardware for the current Farmbot to perform its primary functions, and to create a template for a system that would be adaptable for future users and developers. The scope of the project included creating a universal tool mount, a seeding system, and a watering and nutrient mixing system. This project was brought to the students by sponsor Rory Aronson, the creator of Farmbot. The Cal Poly Farmbot team was able to go through an extensive brainstorming and iterative process for each part, where testing was able to be incorporated immediately due …