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California Polytechnic State University, San Luis Obispo

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Articles 5701 - 5730 of 7978

Full-Text Articles in Engineering

Enhancement Of Light Absorption Efficiency Of Solar Cell Using Dual, Ashton Ellaboudy Dec 2011

Enhancement Of Light Absorption Efficiency Of Solar Cell Using Dual, Ashton Ellaboudy

Master's Theses

In this research we study the effect of adding a single diffraction grating on top of a solar cell. We simulated the square diffraction grating, as well as triangular diffraction grating. The single square grating showed more favorable results, achieved 330% power improvement compared to 270% power improvement in the single triangular grating case.

We simulated a triangle/triangle (top-bottom) and triangular/rectangular (top-bottom) grating cases. The Triangular grating achieved higher light absorption compared to rectangular grating. The best top grating was around 200nm grating period. We realized solar cell efficiency improvement about 42.4% for the triangular rectangular (top-bottom) grating.

We studied …


Irrigation Engineering In Seismic Zones - Mexicali Valley, Mexico, Alan Dennis Gracia, Charles M. Burt, Mario Paredes Vallejo Nov 2011

Irrigation Engineering In Seismic Zones - Mexicali Valley, Mexico, Alan Dennis Gracia, Charles M. Burt, Mario Paredes Vallejo

BioResource and Agricultural Engineering

On April 4, 2010 an earthquake of Richter magnitude 7.2 occurred with an epicenter south of Mexicali within the irrigated zone of Mexicali Valley. Extensive damage occurred to main and lateral canal structures, plus to field irrigation systems and the main drainage network. This paper describes the engineering for a new major irrigation water conveyance system to service the most heavily impacted zone of 80,000 acres. Considerations included identification of the causes of the damage, selection of canal versus pipeline, relocation costs of people along new routes, and improved flexibility of water delivery. Major investigations regarding soils, topography, etc. were …


Electric Vehicle Safety, Art Maccarley Nov 2011

Electric Vehicle Safety, Art Maccarley

Electrical Engineering

No abstract provided.


Velocity Contour Weighting Method. Ii: Evaluation In Trapezoidal Channels And Roughness Sensitivity, Daniel Howes, Brett F. Sanders Nov 2011

Velocity Contour Weighting Method. Ii: Evaluation In Trapezoidal Channels And Roughness Sensitivity, Daniel Howes, Brett F. Sanders

BioResource and Agricultural Engineering

The Velocity Contour Weighting Method (VCWM) was developed in Part I to accurately estimate the cross-sectional average velocity of a prismatic channel flow using acoustic Doppler velocity meter (ADVM) measurements of centerline velocity. Here, the VCWM is validated by its successful application to 25 different concrete-lined trapezoidal channels used for irrigation water delivery. At each site, the cross-sectional distribution of velocity is measured by an acoustic Doppler velocimeter (ADV), which is moved horizontally and vertically through a sampling grid. Multiple tests at some sites led to a total of 51 sets of cross-sectional measurements. ADVM measurements are simulated by interpolating …


Velocity Contour Weighting Method. I: Algorithm Development And Laboratory Testing, Daniel J. Howes, Brett F. Sanders Nov 2011

Velocity Contour Weighting Method. I: Algorithm Development And Laboratory Testing, Daniel J. Howes, Brett F. Sanders

BioResource and Agricultural Engineering

An algorithm is developed for real-time estimation of the cross-sectional average velocity of a channel flow by using an upward-looking pulsed wave acoustic Doppler velocity meters (ADVM). The Velocity Contour Weighting Method (VCWM) is applicable to gradually varied flows in prismatic channels and requires little to no calibration. VCWM estimates the average velocity as a weighted average of ADVM bin velocities. Weights are based on the velocity distribution sampled by the ADVM. Collectively, the VCWM is able to adapt to a wide range of channel geometry and roughness features. Expressions for the velocity weights are developed by first applying a …


Agricultural Irrigation Using Municipal Effluent, Charles M. Burt Nov 2011

Agricultural Irrigation Using Municipal Effluent, Charles M. Burt

BioResource and Agricultural Engineering

The paper describes the development of a design and management plan for disposing of secondary effluent originating in the urban communities. It highlights the differences in approach that a public utility must take, versus a typical agricultural irrigation application. Costs and requirements for municipal effluent irrigation are many times greater. The complexity of regulations and agency procurement procedures relegates the actual irrigation system design to a relatively small role in the total project.


Effects Of Column Stiffness On Seismic Behavior Of Steel Plate Shear Walls, Xuhua Guo Nov 2011

Effects Of Column Stiffness On Seismic Behavior Of Steel Plate Shear Walls, Xuhua Guo

Master's Theses

Steel plate shear walls (SPSWs) are a lateral force resisting system consisting of thin infill steel plates surrounded by boundary frame members. The infill steel plates are allowed to buckle in shear and subsequently form diagonal tension field actions during earthquake events. Hysteretic energy dissipation of this system is primarily achieved through yielding of the infill plates. Conceptually, in a SPSW system with ideally rigid columns pinned to ground, the infill plates at different stories will yield simultaneously as a result of the lateral loads. However, when the columns become flexible, infill plate yielding may initially occur at one story …


Engineering On The Rose Float: Final Project Report, Stephen Boles, Garrett Dong, Peter Hoonhout Nov 2011

Engineering On The Rose Float: Final Project Report, Stephen Boles, Garrett Dong, Peter Hoonhout

Mechanical Engineering

The purpose of this project is to design the simple mechanical movement systems of the 2012 Cal Poly Tournament of Roses Float Parade to prevent failure. Three mechanisms were designed. One of the mechanisms is a tall building that has a superhero and helicopter rotating around the top; it also has the ability to rotate the top 2/3rds of the mechanism to a 90 degree angle to fit under a 16.5 foot bridge. Another mechanism is the cars that look like they are driving on the pod’s road surface via train tracks underneath the surface. The cars will travel …


Analysis Of 26" And 29" Wheel Mountain Bikes, Jacob Publicover, David Wang, Alex Warring Nov 2011

Analysis Of 26" And 29" Wheel Mountain Bikes, Jacob Publicover, David Wang, Alex Warring

Mechanical Engineering

There are two major mountain bike diameter wheel sizes on the market today, but with two different options, one would naturally wonder, “Which one is best?” During the course of this project, 26 and 29 inch wheel mountain bikes were analyzed quantitatively and qualitatively, using a variety of test methods, from heart rate monitoring to serial data acquisition to computer simulated analyses; static, dynamic, theoretical, and subjective tests were administered.


Impacts Of Plug-In Electric Vehicle On Residential Electric Distribution System Using Stochastic And Sensitivity Approach, Henry Chigozie Ureh Nov 2011

Impacts Of Plug-In Electric Vehicle On Residential Electric Distribution System Using Stochastic And Sensitivity Approach, Henry Chigozie Ureh

Master's Theses

Plug-in Electric Vehicles (PEVs) are projected to become a viable means of transportation due to advances in technology and advocates for green and eco-friendly energy solutions. These vehicles are powered partially, or in some cases, solely by the energy stored in their battery packs. The large sizes of these battery packs require large amount of energy to charge, and as the demand for PEV increases, the increase in energy demand needed to recharge these PEV batteries could pose problems to the present electric distribution system. This study examines the potential impacts of PEV on a residential electric distribution system at …


Formulation Of An Optimal Search Strategy For Space Debris At Geo, Daniel J. Jackson Nov 2011

Formulation Of An Optimal Search Strategy For Space Debris At Geo, Daniel J. Jackson

Master's Theses

The purpose of this thesis is to create a search strategy to find orbital debris when the object fails to appear in the sky at its predicted location. This project is for NASA Johnson Space Center Orbital Debris Program Office through the MODEST (Michigan Orbital Debris Survey Telescope) program. This thesis will build upon the research already done by James Biehl in “Formulation of a Search Strategy for Space Debris at GEO.” MODEST tracks objects at a specific right ascension and declination. A circular orbit assumption is then used to predict the location of the object at a later time. …


Wavelength Dependence Of Transverse Mode Coupling With/Without E-Block Of Gan Laser Cavity, Krishneel Lal Nov 2011

Wavelength Dependence Of Transverse Mode Coupling With/Without E-Block Of Gan Laser Cavity, Krishneel Lal

Electrical Engineering

No abstract provided.


Themed Ride Vehicle Concept Design, Ryan Alletag Nov 2011

Themed Ride Vehicle Concept Design, Ryan Alletag

Liberal Arts and Engineering Studies

No abstract provided.


Implementation And Validation Of The Ζ-F And Asbm Turbulence Models, Dustin Van Blaricom Quint Nov 2011

Implementation And Validation Of The Ζ-F And Asbm Turbulence Models, Dustin Van Blaricom Quint

Master's Theses

The use of Computational Fluid Dynamics (CFD) tools throughout the engineering industry has become standard. Simulations are used during nearly all steps throughout the life cycle of products including design, production, and testing. Due to their wide range of use, industrial CFD codes are becoming more flexible and easier to use. These commercial codes require robustness, reliability, and efficiency. Consequently, linear eddy viscosity models (LEVM) are used to model turbulence for an increasing number of flow types. LEVM such as k-ε and k-ω provide modeling with little loss of computational efficiency and have proven to be robust. The LEVM that …


Detecting Suspicious Behavior With Low-Cost Sensors, Ahren Alexander Reed Nov 2011

Detecting Suspicious Behavior With Low-Cost Sensors, Ahren Alexander Reed

Master's Theses

A proof of concept is created that demonstrates how low-cost sensors and a simple software solution can be used to proactively detect IED placement. The main goal is to detect suspicious behavior; Specifically we derive requirements that loitering, meandering, improper location and object placement shall be detected. Current methods being used to detect Improvised Explosive Devices (IEDs) are costly in terms of equipment and risk to life, and many are retroactive; IED detection occurs long after explosives are placed. A prototype system is explored with the quality attributes of being low-cost, proactive and using simple software methods. A wireless sensor …


A Study Of Solder Joint Failure Criteria, Jianbiao Pan, Julie Silk Oct 2011

A Study Of Solder Joint Failure Criteria, Jianbiao Pan, Julie Silk

Industrial and Manufacturing Engineering

One of the challenges in an experimental study of solder joint reliability is to determine when cracks occur in a solder joint or when a solder joint fails. Cracks in a real solder joint are difficult to identify using an X-Ray system. Cross-sectioning and scanning electron microscopy (SEM) is a destructive method. A common non-destructive test method is to monitor resistance increase in a solder joint or a daisy-chain. However, no scientific research has been done in establishing the relationship between the crack area of an interconnection and the change in resistance of the interconnection. This paper proposes a method …


The Irrigation Sector Shift From Construction To Modernization: What Is Required For Success?, Charles M. Burt Oct 2011

The Irrigation Sector Shift From Construction To Modernization: What Is Required For Success?, Charles M. Burt

BioResource and Agricultural Engineering

External pressures related to environmental protection, commodity prices, energy availability, larger populations, and climate change have combined to require an immediate and substantial improvement in agricultural irrigation performance. Worldwide progression towards modernized irrigation projects has been uneven and slower than desired, but decades of irrigation modernization development have clarified certain requirements for success, as well as illuminated indicators of project failure. Of particular importance are required shifts within the state and national irrigation bureaucracies, as well as universities.


Considerations For Numerical Modeling Of Inverted Wings In Ground Effects, Graham Doig, Tracie J. Barber Oct 2011

Considerations For Numerical Modeling Of Inverted Wings In Ground Effects, Graham Doig, Tracie J. Barber

Aerospace Engineering

No abstract provided.


Effect Of Gold Content On The Reliability Of Snagcu Solder Joints, Jianbiao Pan, J. Silk, M. Powers, P. Hyland Oct 2011

Effect Of Gold Content On The Reliability Of Snagcu Solder Joints, Jianbiao Pan, J. Silk, M. Powers, P. Hyland

Industrial and Manufacturing Engineering

Electroplated Ni/Au over Cu is a popular metallization for printed circuit board finish as well as for component leads, especially wire-bondable high-frequency packages, where the gold thickness requirement for wire bonding is high. The general understanding is that less than 3 wt% of Au is acceptable in SnPb solder joints. However, little is known about the effect of Au content on the reliability of SnAgCu solder joints. The purpose of this paper is to determine the acceptable level of Au in SAC305 solder joints. Three different package platforms with different Au thicknesses were assembled on boards with two different Au …


Performance Analysis Of A Variable Conductance Heat Pipe, Herron Arreola Oct 2011

Performance Analysis Of A Variable Conductance Heat Pipe, Herron Arreola

Aerospace Engineering

This report examines the analysis of a donated Boeing variable conductance heat pipe with unknown performance characteristics. These characteristics were found through experimental means by utilizing 14 thermocouples attached to various locations on the heat pipe, the heaters and to the insulation. Although the maximum axial heat transport capability could not be determined due to the limited number of strip heaters available, the maximum radial heat flux capability of the heat pipe was found to be 2.46 W/in2. The experiment also revealed that increasing the input power decreased the burn out inclination angle and that using a coolant …


Constrained Hermite Tls For Mesh-Free Derivative Estimation Near And On Boundaries, Robert A. Mcdonald, Alejandro Ramos Oct 2011

Constrained Hermite Tls For Mesh-Free Derivative Estimation Near And On Boundaries, Robert A. Mcdonald, Alejandro Ramos

Aerospace Engineering

A Taylor series least-squares approach to estimating derivatives on scattered data is extended to include derivative observation or specification. This approach allows improved estimation of derivatives near boundaries as compared with the standard ghost node approach. It also enables a unique method of estimating derivatives in a surface using only surface data.


Development And Prototyping Of A Ground Fault Circuit Interrupter For 3-Phase 480 Volt Systems, Matthew R. Norlander Oct 2011

Development And Prototyping Of A Ground Fault Circuit Interrupter For 3-Phase 480 Volt Systems, Matthew R. Norlander

Master's Theses

Ground Fault Circuit Interrupter (GFCI) technology was first introduced in the NEC in 1971, yet four decades later the technology has not been introduced to a great extent outside of the home environment. This thesis introduces the difficulties encountered in low-voltage three phase ground fault current detection, and adopts a previously patented tripping scheme to develop and prototype a digital relay for 3-phase 480 volt systems capable of the sensitivity and speed required for personnel safety. Results demonstrate the feasibility of the concept and suggest commercial development should be pursued. The prototype is capable of mA sensitivity and reliably detects …


An Automated Test Station Design Used To Verify Aircraft Communication Protocols, Joshua Berrian Oct 2011

An Automated Test Station Design Used To Verify Aircraft Communication Protocols, Joshua Berrian

Master's Theses

Requirements verification is typically the costliest part of the systems engineering design process. In the commercial aircraft industry, as the software and hardware design evolves, it must be verified to conform to requirements. In addition, when new design releases are made, regression analysis must be performed which usually requires repeat testing. To streamline verification, a suite of automated verification tools is described in this document which can reduce the test effort. This test suite can be qualified to be used to verify systems at any DO-178B design assurance level. Some of the software tools are briefly described below.

There are …


A Parallel Energy-Sharing Control For Fuel Cell-Battery- Ultracapacitor Hybrid Vehicle, Jennhwa Wong, N.R. N. Idris, Makbul Anwari, Taufik Taufik Sep 2011

A Parallel Energy-Sharing Control For Fuel Cell-Battery- Ultracapacitor Hybrid Vehicle, Jennhwa Wong, N.R. N. Idris, Makbul Anwari, Taufik Taufik

Electrical Engineering

This paper proposes a parallel energy-sharing control for fuel cell hybrid vehicles (FCHVs) application. The hybrid source consists of fuel cells (FCs) stack, battery packs and Ultracapacitor (UC) modules. In the proposed parallel energy sharing control, each source is connected to a DC bus via power electronics converters. A total of six control loops are applied in the supervisory system in order to regulate the DC bus voltage, control of power flow and at the same time to monitor the state of charge (SOC) of each energy storage device. Simulation with experiment verifications are carried out to verify the proposed …


Assessing Near-Field Black Carbon Variability Due To Wood Burning And Evaluating Regression Models And Isc Dispersion Modeling, Stella Tan Sep 2011

Assessing Near-Field Black Carbon Variability Due To Wood Burning And Evaluating Regression Models And Isc Dispersion Modeling, Stella Tan

Master's Theses

PM2.5 variability within the neighborhood scale has not been thoroughly studied for wood burning communities. High variability in near-field PM2.5 concentration may lead to harmful public exposure since monitoring does not occur on that scale. This study measures near-field PM2.5 variability by measuring black carbon (BC), a component of PM2.5, in a 1 km2 area located in Cambria, California. BC and meteorological data (when meteorological instruments were available) were measured over thirteen 12-hour intensive operation periods (IOPs) occurring over the winters of 2009 and 2010. Near-field BC variability was measured to understand the type …


A Quantitative Study Of The Weldability Of Inconel 718 Using Gleeble And Varestraint Test Methods, Sean Quigley Sep 2011

A Quantitative Study Of The Weldability Of Inconel 718 Using Gleeble And Varestraint Test Methods, Sean Quigley

Master's Theses

Nickel super alloy Inconel 718 was tested and compared to Haynes 230 using Gleeble and Varestraint mechanical test methods. Hot cracking susceptibility was examined in either alloy using a sub-scale Varestraint test method at 5 augmented strain levels: 0.25%, 05.%, 1%, 2%, and 4%. Maximum crack length, total crack length, and number of cracks were measured for each strain level. Gleeble hot ductility on-heating and on-cooling tests were performed on both alloys. Inconel 718 was tested on-heating at target temperatures of 1600˚F, 2000˚F, 2100˚F, 2200˚F, and on cooling at 1600˚F, 1700˚F, 1800˚F, 1900˚F, and 2100˚F. Haynes 230 was tested on-heating …


Mission Performance Considered As Point Performance In Aircraft Design, Robert A. Mcdonald Sep 2011

Mission Performance Considered As Point Performance In Aircraft Design, Robert A. Mcdonald

Aerospace Engineering

The cruise or loiter performance of an aircraft is intimately tied to its wing loading and its thrust-to-weight ratio. Paradoxically, mission performance is often not considered when these fundamental aircraft parameters are determined in conceptual design. In this paper, the traditional constraint diagram is extended to include contours of range or endurance parameter. These performance metrics represent the mission-performance capability of the aircraft without sizing the aircraft to a particular mission. This gives the designer an immediate and intuitive understanding of the tradeoff between the point and mission performance of the aircraft. The potential freedom for the designer to choose …


Quality Of Traffic Flow On Urban Arterial Streets And Its Relationship With Safety, Vinayak V. Dixit, Anurag Pande, Mohamed Abdel-Aty, Abhishek Das, Essam Radwan Sep 2011

Quality Of Traffic Flow On Urban Arterial Streets And Its Relationship With Safety, Vinayak V. Dixit, Anurag Pande, Mohamed Abdel-Aty, Abhishek Das, Essam Radwan

Civil and Environmental Engineering

The two-fluid model for vehicular traffic flow explains the traffic on arterials as a mix of stopped and running vehicles. It describes the relationship between the vehicles’ running speed and the fraction of running vehicles. The two parameters of the model essentially represent ‘free flow’ travel time and level of interaction among vehicles, and may be used to evaluate urban roadway networks and urban corridors with partially limited access. These parameters are influenced by not only the roadway characteristics but also by behavioral aspects of driver population, e.g., aggressiveness. Two-fluid models are estimated for eight arterial corridors in Orlando, FL …


Design Of A University Research Network: Analysis, Selection, And Implementation Planning, Anna P. Hopper Sep 2011

Design Of A University Research Network: Analysis, Selection, And Implementation Planning, Anna P. Hopper

Master's Theses

This report focuses on the design of a university knowledge management system (KMS), and how such a system can provide the framework for students and faculty to partake in, share, and collaborate on research activities. The collaborative environment of a university KMS, or research network, must be established in order for a university to maintain its reputation as a competitive research institution and to develop its faculty and students outside the classroom. A research network may contain a variety of features, some of which include faculty profiles, forums, communication portals, publication links, biographies, faculty keywords, interest areas and contact information. …


California Polytechnic State University Wind Resource Assessment, Jason Allan Smith Sep 2011

California Polytechnic State University Wind Resource Assessment, Jason Allan Smith

Master's Theses

Wind resource assessment at California Polytechnic State University shows there is potential for wind power generation on Cal Poly land. A computational fluid dynamics model based on wind data collected from a campus maintained meteorological tower on Escuela Ranch approximately 5 miles northwest of campus suggests there are areas of Cal Poly land with an IEC Class III wind resource at a height of 80 meters above ground. In addition during the daytime when the campus uses the most energy there are large portions of land with annual average daytime wind speeds above 6.9m/s. These areas have been identified by …