Engineering Commons^™

Challenges In Transdisciplinary, Integrated Projects: Reflections On The Case Of Faculty Members’ Failure To Collaborate, Linda Vanasupa, Kathryn E. Mccormick, Carolyn J. Stefanco, Roberta J. Herter, Margot Mcdonald

Materials Engineering

In this article we describe the challenges of transdisciplinary teamwork involving four faculty members from dissimilar epistemological traditions in the process of developing a manuscript on the lessons learned in our teaching collaboration. Our difficulty originated in implicit mental models and assumptions that caused incongruence between our intent to collaborate and the (habituated) relationship structure of the partnership. The dynamics are described through the lens of Tannenbaum and Schmidt’s leadership model and Aristotle’s causality. We suggest that successful collaboration necessitates careful attention to the process of establishing the collaboration, its structure, and the metacognitive capacities to see one’s own thinking, …

The Synthesis And Characterization Of Gold And Silver Nanoparticles In Formal And Informal Settings, Mathew Wynn

Materials Engineering

Silver nanoparticles were synthesized through the reduction of AgNO3 using NaBH4. The borohydride anions were adsorbed onto silver nanoparticles. The repelling forces of the borohydride anions prevented the aggregation of particles, but the addition of an electrolyte or agitation induced aggregation. A yellow hue was given off by the silver nanoparticle sol that, using a spectrophotometer, had plasmon resonance at 386 nm. The silver nanoparticles were estimated to be 10 to 20 nm in diameter. Gold nanoparticles were synthesized through the reduction of HAuCl4 using Na3C6H5O7. The gold nanoparticle sol gave off a red hue that had plasmon resonance at …

Characterization And Analysis Of Low Room Temperature Ductility Nickel-Based Superalloy 718 Plus For Aircraft Engine Forgings, Jonathon Bracci

Materials Engineering

Schlosser Forge Co. forges low pressure turbine (LPT) cases from the nickel based superalloy 718 Plus using the ring rolling forging process. Schlosser has been experiencing low room temperature ductility problems in a number of their 718 Plus LPT cases. LPT cases are required to pass a 4D tensile test at room temperature with a minimum of 15 percent elongation. The ductility problem was reduced by increasing the forging temperature from 1825˚F to 1850˚F. Analysis was performed on 718 Plus samples taken from forged LPT cases that failed the room temperature ductility requirement and ones that passed the requirement. The …

Blunt Impact Performance Evaluation Of Helmet Lining Systems For Military And Recreational Use, Jaclyn Siniora, Ryan Taylor, Darren Suey

Industrial Technology and Packaging

With the increasing problem in collegiate athletes experiencing injuries to the brain, different helmet liners where put to the test to see which liner provided athletes the greatest protection under specific conditions.

This senior project evaluates five different liners in football helmets. Each of the helmet liners were tested at three different temperatures: hot, cold, and ambient. Each helmet had seven different impact locations which were put to the test. The project was designed to be used to test ACH military combat liners as well. Due to shipping bottle necks the ACH combat liners have been left to future Cal …

Determining An Inorganic Mineralization Process To Inhibit Organic Degradation And Preserve The Dimensional Stability Of Bamboo, Eric Hahn

Materials Engineering

Bamboo is a renewable natural composite with potential as both a construction and synthesis material. The components of bamboo are cellulosic vascular bundles imbedded within a lignin matrix that create a porous hierarchical structure. This structure has low density while maintaining high strength, toughness, and elasticity, but is susceptible to organic decay. A study was performed to evaluate the effect of varying bamboo culm age (1-3 years) and density (0.72-1.05 g/cm³) on the ability to control inorganic mineral precipitation to prevent degradation and preserve dimensional stability of the organic matrix. Internodal culm samples were immersed in solutions of …

Development Of A Flight Test Program For A Homebuilt Zenith Stol Ch 701, Reed Danis, Dave Nguyen

Aerospace Engineering

The objective of this senior project is to prepare a phase I flight test program for a homebuilt Zenith CH 701 kit aircraft. The CH 701 is a small, short takeoff and landing experimental aircraft. A team including several Cal Poly students helped to construct the airframe and avionics of a 701 during the 2011-2012 academic year. The flight test program is necessary for obtaining unrestricted FAA flight certification for the completed aircraft. A set of test flight cards were created to aid in meeting the 25 to 40 hours of required phase I flight testing. These cards include specific …

Biaxial & Twist Testing Of Composite Carbon-Fiber Sandwich Panels For Automotive Racing Vehicles, Erik Eckberg

Materials Engineering

Composite sandwich panels were constructed with 4-ply plain weave carbon-fiber/epoxy face sheets in the 0^o/45^o/0^o/45^o orientation and 1/8^th inch Nomex honeycomb core. The panels were cut into 5-inch square test plates for mechanical testing. All testing was done on a fixture designed and fabricated by Pratt & Miller Engineering and installed on an Instron testing system at Cal Poly. The twist test was performed by supporting diagonal corners of the plate while simultaneously loading the opposite two corners at a crosshead rate of .06 in/min (ASTM 3044-94R11). Out of 10 panels tested, …

The Design And Fabrication Of A Silicon Membrane For Electrostatic Actuation, Elizabeth L. Brooks

Materials Engineering

An electrostatically actuated silicon membrane was designed and fabricated utilizing a siliconon- insulator wafer. The SOI wafer contains three layers- a 400μm thick “handle” layer of silicon followed by a 2μm thick oxide layer topped with a 20μm thick “device” layer of silicon. The embedded oxide layer acts as an etch-stop during silicon etching, leaving a thin membrane of consistent thickness on the device side. The device dimensions were chosen to provide acceptable membrane deflection predicted by calculations and Finite Element Analysis. A microfabrication process plan was designed to produce thin membranes appropriate for electrostatic actuation. A 700nm layer of …

De-Orbiting Upper Stage Rocket Bodies Using A Deployable High Altitude Drag Sail, Robert A. Hawkins Jr., Joseph A. Palomares

Aerospace Engineering

This report examines the effectiveness of a drag sail to de-orbit upper stage rocket bodies. Many other perturbations contribute to the de-orbiting of these rocket bodies, and these perturbations will also be discussed briefly. This paper will show the length of time needed to force the altitudes of various launch vehicle stages with varying drag area sizes to less than 100 km. The upper stage of the Delta IV launch vehicle in an orbit with an altitude of 500 km will naturally de-orbit in 720 days but when equipped with a 20 m² drag sail, it will de-orbit in …

A Study On Organic Epoxy And Hemp Composite Plates With An Emphasis On Mechanical And Finite Element Analysis, Alma Melendez

Aerospace Engineering

Several vibration and tensile tests were conducted for four natural fiber hemp composites in order to observe its behavior and acquire the material properties of hemp. Two plates were made on the Cal Poly press table, while the other two plates were made on the Cal Poly vacuum table. All four plates are made of 100% hemp under three different types of weave. The first plate is called CTPT-12, has a thickness of 0.053 inches, and was made on the press table. The second plate is called CTL4 with a thickness of 0.152 inches and made on the press table. …

Coseismic Tectonic Surface Deformation During The 2010 Maule, Chile, MW 8.8 Earthquake, Keith Kelson, Robert C. Witter, Andrés Tassara, Isabelle Ryder, Christian Ledezma, Robb Moss, Laurie Johnson

Civil and Environmental Engineering

Tectonic deformation from the 2010 Maule (Chile) M_w 8.8 earthquake included both uplift and subsidence along about 470 km of the central Chilean coast. In the south, deformation included as much as 3 m of uplift of the Arauco Peninsula, which produced emergent marine platforms and affected harbor infrastructure. In the central part of the deformation zone, north of Constitución, coastal subsidence drowned supratidal floodplains and caused extensive shoreline modification. In the north, coastal areas experienced either slight uplift or no detected change in land level. Also, river-channel deposition and decreased gradients suggest tectonic subsidence may have occurred in …

Ramjet Fuel System, Kelsey Selin

Aerospace Engineering

No abstract provided.

Empennage Sizing And Aircraft Stability Using Matlab, Ryan C. Struett

Aerospace Engineering

No abstract provided.

Degradation Of Solar Cells Due To Arcing In A Vacuum Chamber, Christina Gonzalez

Aerospace Engineering

This report summarizes the senior project entitled Degradation of Solar Cells Due to Arcing in a Vacuum Chamber. The goal of this experiment was to show electrical and physical degradation of silicon solar cells in a vacuum chamber. The cells were characterized and then placed in a vacuum chamber. Under vacuum, a potential was created to induce arcing to the cell. The cell was characterized again after arcing to determine the change in efficiency. This document details the process for designing the circuit to create the arcing, and the different setups used to degrade the cells electrically and physically. It …

Effects Of Beta Stabilizers On Quench Delay Susceptibility Of Ti-6al-4v, Kyle Logan

Materials Engineering

Tensile samples of Titanium 6Al-4V (Ti-6Al-4V) were machined from forgings containing rich and poor amounts of beta stabilizers in their compositions. The tensile samples were each heat treated two times. In the first round of heat treatments, the samples were either beta solution treated (BST), or solution treated (ST). Each sample was water quenched with varying quench delays of 10, 20, and 30 seconds. BST treated specimens were then overaged at 1350°F for 2 hours and air cooled (BSTOA); while the ST treated samples were aged at 990°F for 6 hours and air cooled (STA). Following heat treating, the tensile …

The Study Of Natural Composite I-Beam In A Three Point Bending Test, Abdel Shabbar

Aerospace Engineering

The objective of this experiment is to conduct a series of unidirectional tensile test on several samples of natural occurring plant fibers. Among the materials tested, hemp has proven to be the most promising candidate as the base material in creating an all-natural composite I-Beam. This I-Beam will be entered into the annual SAMPE 2012 competition to compete against other schools and universities nationwide. These I-Beams will undergo a three point bending test, and must withstand the greatest load whilst remaining in the parameters set by SAMPE. This I-Beam will go on to take third place internationally. In addition, the …

Flaperon Assembly Manual For Pegastol Aftermarket Wings, Eric Alan Gray

Aerospace Engineering

No abstract provided.

Assembly Of A Passive Slat System For A Ch-701 Kit Aircraft, Jordan Coenen, Spencer Spagnola

Aerospace Engineering

No abstract provided.

Computation Time Comparison Between Matlab And C++ Using Launch Windows, Tyler Andrews

Aerospace Engineering

Processing speed between Matlab and C++ was compared by examining launch windows and handling large amounts of data found in pork chop plots. A compilation of code was generated in Matlab to produce the plots and an identical file was created in C++ that was then compiled and run in Matlab to plot the data. This file is known as a MEX-file. This report outlines some of the basics when working with MEX-files and the problems that face users. For Lambert’s solver, multi revolution cases were considered and some pork chop plots of single revolution trajectories were plotted. Three different …

Preliminary Design Of A Laboratory Cylindrical Hall-Effect Thruster, Scott Mcgrail, Sam Parker

Aerospace Engineering

A 3-cm cylindrical Hall thruster with permanent magnets was designed and modeled. The goal was to design a Hall thruster for Cal Poly’s propulsion laboratory of similar size and performance as Cal Poly’s MiXI thruster. The design process began with an investigation into the physics of Hall thrusters and selection of certain thruster parameters. The selected parameters were the diameter and depth of the channel, the total power input to the system, the discharge supply voltage, the cathode voltage, and the propellant flow rates to the anode and cathode. These parameters were used to determine the operational characteristics of the …

Applied Computer Cooling, Spencer Ellsworth

Liberal Arts and Engineering Studies

No abstract provided.

Data Acquisition For Flight Tests Using Handheld Gps And Electronic Flight Instrument System, Christopher Michael Gocha

Aerospace Engineering

No abstract provided.

The Dancer's Friend - A Wearable Electronics Investigation, Paul Case

Computer Engineering

This project is an initial investigation into the use of wearable electronics for wireless gesture detection, with the end goal of an application of augmenting dance performance through the use of gesture controlled sound. Though the system developed is not as yet of practical use to a dance performer, it lays the groundwork for future development and expansion, in both hardware and software design. In particular, it provides an in-depth overview of the lessons learned regarding the special hardware development considerations in wearable electronics to help ensure the success of future developments.

Evaluation Of Corrosion Properties For Use Of Az31b In Bioabsorbable Stents And In Vivo Corrosion Rate Prediction Using Fea, Jared Vidales, Austin Schader, Jenna Jerman, Michael Turovskiy

Materials Engineering

AZ31B was heat treated to evoke more controlled and uniform corrosion. 1/16” diameter AZ31B wire was cut into six samples each 1” long. The samples underwent heat treatments following ASTM B661-06. Samples were weighed and placed into three different in vitro environments. In the first scenario two samples of each heat treatment were individually placed in 50 ml of saline solution at 0.9% sodium, in a static test tube at 37°C temperature. Two samples were placed in 100 ml of 0.9% saline solution in a 250 ml stirring beaker with an average whirlpool depth of 1”. Two of each sample …

Effects Of Alternate Cementitious Materials On Compressive Strength And Environmental Impacts Of Cement Mix Designs., Mitchell R. Bush

Materials Engineering

Specific proportions of Portland cement, fly ash, and blast furnace slag cement mixtures where chosen by a ternary phase diagram to be investigated. By experimental testing and company data history fly ash was limited to not exceed 30% and contribution of Portland cement must be over 50%. Ten chosen mix designs were batched by following ASTM C305-94 and cured for twenty-eight and forty-two days, the extended cure length allows the reaction of pozzolanic material with calcium hydroxide to complete. Compressive strength testing at forty-two days yielded low strength for mix designs with 20% or less Portland cement compared to our …

The Characterization And Comparison Of Biochar Produced From A Decentralized Reactor Using Forced Air And Natural Draft Pyrolysis, Leah Herbert, Ian Hosek, Rishi Kripalani

Materials Engineering

The soil additive properties of biochar have proven both effective and globally beneficial, but depend heavily on feedstock used and process conditions. This study characterizes how forced and natural draft air flows affect the biochar’s soil amendment potential. Biochars manufactured from two pine species of feedstock, in timber and pellet form, were compared against a designer biochar. The designer biochar held the lowest C:N ratio (57.43), followed by the natural draft pellets (199.5), forced air timber (282.5), forced air pellets (422.7), and natural draft timber (503.7). The designer char had the largest cation exchange capacity at 138.5 cmolc/kg; the decentralized …

Microstructural Characterization Of Ti-6al-4v And Its Relationship To Sample Geometry, Blake Gaspar

Materials Engineering

A problem exists with a part produced by forging made by Shultz Steel of Ti-6Al-4V in the variance of properties throughout the part. There is one specific region that exhibits the most variance. The purpose of the report is to determine any microstructural differences within the region of interest in the part. When microstructures of the inner section and outer section of the part were looked at it was determined that they exhibited a martensitic structure. There was a noticeable difference in the lath structure between sections. The outer region contained larger more widely spread laths of an average length …

Artificial Alveolar-Capillary Membrane On A Microchip, Keith Male

Materials Engineering

A microfluidic device was synthesized out of polydimethyl siloxane (PDMS) to simulate the structure of the alveolar-capillary interface of the human lung. Soft lithography techniques were used to build a mold structure out of SU-8 epoxy at heights ranging from 30µm to 110 µm on a silicon substrate, with the 70 µm structure working the best. A mixture of 10:1 Sylgard 184 elastomer was then cast using the mold, and cured at a temperature of 80^oC. For the porous membrane, the PDMS was spun on at 6000rpm for 30 seconds using a spin coater to produce a membrane …

Bond Strength Characterization Of Su-8 To Su-8 For Fabricating Microchannels Of An Electrokinetic Microfluidic Pump, Nash Anderson

Materials Engineering

Photosensitive negative resist polymer layers of SU-8 2050 were adhered to 100 mm n-type silicon and Pyrex wafers via spin coating. These wafers were then bonded together at various temperatures of 100 ͦC, 120 ͦC, 140 ͦC, 150 ͦC, 160 ͦC, and 180 ͦC. The target thickness of each SU-8 layer was 100 µm. Photolithography was used to create microfluidic channels within the SU-8. An n-type silicon wafer and a Pyrex wafer, each with an SU-8 layer, were brought together on the “hard bake” or final step of SU-8 polymerization. A pressure of ~300 KPa was applied during the hard …

Design And Fabrication Of Serpentine-Hinged Silicon Micro-Mirror Devices, Nicholas Wiswell

Materials Engineering

Seven different actuating micro-mirror designs were created and verified via finite element analysis. Two were straight torsion beam hinge designs representative of previous work at Cal Poly; the remaining five were new designs incorporating serpentine hinges. The surface area of these mirror devices ranged from 0.5 square millimeters to 12.5 square millimeters. Geometric patterns representing the device profiles were created and used to obtain photolithographic masks. Beginning with a 400μm thick, 100mm diameter silicon on insulator wafer, a silicon dioxide layer was thermally grown on the surface at 1050 degrees Celsius. Positive photoresist was then spun onto the wafer at …