Engineering Commons^™

Understanding The Effects Of Temperature Extremes On The Tensile And Short Beam Shear Strength Of Epoxy-Based, Glass-Fiber Reinforced Composites, Jonathan Blake Patterson

Materials Engineering

Aptera (Oceanside, CA) has developed two epoxy-based, silica fiber-reinforced composites to be used on their three-wheeled all-electric vehicle called the 2e. Aptera’s composites were studied at temperature extremes using a dynamic mechanical analysis (DMA) system and by tensile and short beam shear (SBS) testing using an Instron testing system. These tests were conducted to simulate the loading of the composite in the 2e vehicle. Tensile and short beam shear samples were machined to 150 mm x 25 mm x 2 mm and 40 mm x 13 mm x 6 mm, respectively. DMA samples were machined to 30 mm x 5 …

Artificial Muscle Project: Process Development Of Polydimethyl Siloxane Thin Films For Use In Dielectric Electroactive Polymer Artificial Muscle Actuators, Vincent J. Gayotin, Richard W. Morrison, Paul A. Preisser

Materials Engineering

An artificial muscle design was created founded on the principles of a dielectric electroactive polymer (DEAP), which is fundamentally similar to a capacitor. A polydimethyl siloxane (PDMS)-based elastomer, Sylgard 184 from Dow Corning, was chosen for the design and spun coat onto polystyrene (PS) Petri dishes at varying speeds to create a thin film, using speeds of 2000 rpm, 3000 rpm, 4000 rpm, 5000 rpm, and 6000 rpm. The film thicknesses were measured optically through use of a microscope with coupled computer imaging software to generate a characteristic curve of film thickness to spin speed, achieving a minimum film thickness …

Materials Characterization Of Bamboo And Analysis Of Bonding Strength And Internal Strength As A Structural Member In Reinforced Concrete, Nithi Plangsriskul, Nicholas Dorsano

Materials Engineering

This study evaluates the potential to utilize bamboo as reinforcement in concrete structural members. In this project, the mechanical properties of bamboo were tested, specifically force required to embed a 0.5” diameter ball 0.016” into the bamboo samples and its bonding strength with concrete. One type of bamboo, Bambusa Oldhamii, was cut into eight sections, approximately 2.54 cm wide, along the length of the culm. The compression test recorded the bamboo’s strength at eight points along the length of the internode and at three points along the transverse direction of each specimen. Bambusa Oldhamii’s specimen base 1 data for inner, …

The Effects Of Cure Schedule On Properties Of Glass-Fiber Reinforced Epoxy Matrix Composites, Trevor J. Lee

Materials Engineering

Two different two-component resin systems were cured, via Differential Scanning Calorimetry, for the times recommended by their respective manufacturers. The resin cure schedules were designed to simulate typical and attainable processing conditions; they were cured at 120°F, 140°F, and 160°F, and in-mold post-cured at 200°F, 230°F, and 260°F. The resulting scans were then compared to a baseline cure for each resin system, consisting of two heating-cooling cycles at a constant rate of temperature change. These baseline cures were then used to determine the percent cure of each sample and the shift in glass transition temperature between the baseline cure and …

Investigating The Mechanical Properties Of Compression Molded Carbon Fiber Reinforced Sheet Molding Compound, Bradley A. Jones

Materials Engineering

Callaway Golf receives a proprietary blend of prepreg material from Quantum Composites. Callaway processes the prepreg in-house and supplied 254mm x 254mm x 1.3mm panels of carbon fiber sheet molding compound (CFSMC) for characterizing. Tensile strength was analyzed by conducting tensile tests per ASTM D3039. Tensile coupons were cut to 254mm long by 25.4mm wide. Tabs were constructed from 1.6mm thick GFRP printed circuit board material. A commercial grade two part epoxy was used to bond the tabs to the CFSMC. Tensile results were inconclusive due to consistent fractures occurring outside the gauge lengths of the specimens.

Flexure strength was …

Design And Characterization Of A Process For Bulk Synthesis Of Cadmium Selenide Quantum Dots, Susan Harada

Materials Engineering

The objective of the process is to synthesize quantum dots that will fluoresce over the visible spectrum of 450 to 650nm; then to mix the quantum dots together in a polymer matrix so that when illuminated with a blue LED the mixture yields “white” light. The current quantum dot synthesis is a chemical process that involves adding a room temperature Se-TOP precursor to a 225°C Cd precursor solution to cause nucleation and growth of nanoparticles. This method, however, only yields quantum dots that fluoresce in the 520 to 600nm range. In order to create the “white” light phosphor replacement, red …

The Design And Manufacture Of A Microfluidic Reactor For Synthesis Of Cadmium Selenide Quantum Dots Using Silicon And Glass Substrates, Peter Gonsalves

Materials Engineering

A microfluidic reactor for synthesizing cadmium selenide (CdSe) quantum dots (QDs) was synthesized out of silicon and Pyrex glass. Microfabrication techniques were used to etch the channels into the silicon wafer. Holes were wet-drilled into Pyrex glass using a diamond-tip drill bit. The Pyrex wafer was aligned to the etched silicon wafer and both were anodically bonded to complete the microfluidic reactor. Conditions for anodic bonding were created by exposing the stacked substrates to 300V at ~350^oC under 5.46N of force. Bulk CdSe solution was mixed at room temperature and treated as a single injection. The syringe containing …

Final Design Review: Design Of An Integrated Solar Cell Array To Power A Solar Ear Hearing Aid Battery Recharger, Christina (Chrissa) Blattner, Scott Carey, Jared Myren, Faye Siao

Materials Engineering

As the energy of fossil fuel supplies are fast depleting due to high consumptions of energy by human beings, the need for other sources of energy, such as solar energy, has become a viable option. By creating solar cell arrays the desired voltage can be generated. The overall goal of the Solar Ear project is to create an array of photovoltaic cells connected with aluminum tracings to recharge batteries that are specifically used for hearing aids. The goal embodies two main areas: the design of a processing method to connect the cells during a micro-fabrication process and the creation of …

Oxidation Kinetics Of Silver Thin Films For Antimicrobial Applications In The Health Care Industry, Sean D. Morham

Materials Engineering

To determine if varying city water qualities from around the United States can support a developing “oxidation corrosion of silver thin films” method of creating aqueous ionic silver solutions for the anti-microbial treatment of healthcare linens, a test was devised holding all variables constant with the exception of water quality parameters. This corrosion style test was done in order to assess a pass/fail criteria of 25 ppb ionic silver concentration in the aqueous solutions which resulted from the corrosion of silver thin film coated substrates. Above 25 ppb being a pass, below 25 ppb being a fail. While varying the …

The Effects Of Heat Treatment On Area Percent Porosity And Corrosion Behavior Of High-Nickel Thermal Spray Coatings, Travis Crowe, Alec Guraydin

Materials Engineering

Samples of two Thermal Spray Coating (TSC) alloys on a low carbon steel substrate were obtained: alloy C276 and Nicko-Shield 200. Specimens of each alloy were subjected to heat treatments at temperatures at 1100° for 60 minutes and 1200° for 10 minutes, with some specimens left in the as-sprayed condition. Three replicates were prepared for each condition. Thin 1” strips were cut using a diamond wafering blade for porosity measurements and 2” x 1” specimens were cut for corrosion testing using a SiC abrasive saw. The porosity specimens were mounted in acrylic resin, polished, and examined using SEM. From these …

Characterization Of The Relationship Between The Microstructure And Tensile Strength Of Annealed Ti-6al-4v, Aldo Corona

Materials Engineering

Tensile coupons of Ti-6Al-4V were heat treated at varying annealing temperatures from 1200°F (648°C) to 1450°F (787°C) at 50°F (23°C) increments for 1 hour. The samples were air cooled to room temperature or furnace cooled to 800°F (426°C) followed by air cooling to room temperature. Four tensile coupons were treated at each annealing temperature and cooling rate. Alpha case was observed to form on the surface of the samples post heat treatment with a maximum depth of 25 µm (.001 in). Samples were tensile tested for their ultimate tensile strength, yield strength, and percent elongation. Samples across all annealing temperatures …

Processing Pdms Gecko Tape Using Isopore Filters And Silicon Wafer Templates, Boris Luu

Materials Engineering

Gecko tape was processed through nanomolding involving two types of templates. One template was a Millapore Isopore polycarbonate membrane filter and the other template was an n-type silicon wafer processed to include four different pore diameters. These pore diameters were 20, 40, 80, and 160 microns. AutoCAD was used to design to a mask to be used later during photolithography. Two n-type wafers were sputtered with aluminum, underwent photolithography, and then etched using reactive ion etching. A template was placed into a Petri dish and Sylgard 184 polydimethylsiloxane (PDMS) was poured on the template. Once the PDMS cured, the 1 …

Dissimilar Metal Weld Variability Due To Lot Differences In Nitinol/ Stainless Steel Interface, Matthew R. Rudow

Materials Engineering

Abstract

An experiment was conducted to determine and reduce the causes of variation between a 304 Stainless Steel and super elastic Nickel Titanium dissimilar metal weld. Six factors were established to understand the cause of variation: perpendicularity, final grind, surface finish, weld force, weld pulse duration, and alignment. Using a rotational test with an air piston break pressures were established and charted in Minitab to identify trends. It was shown that weld force and weld pulse duration were the two factors that had the most influence on break strength. This data also showed that higher strength groups had less variability. …

Characterization Of The Oxidation Kinetics Of Fecral Ferritic Stainless Steels At 900°C For Catalytic Converter Applications, Stacy Stamm

Materials Engineering

This study characterized the oxidation kinetics of two types of ferritic stainless steel foils used as substrates for catalytic converters. Catalytic converters rely on an alumina layer on the surface of the foils, which allows the catalyst to attach to the substrate. Because the alumina layer is so important, this study characterized the weight gain, thickness, and composition of the alumina as it grew at 900°C for up to 400 hours. The two foils characterized were an MK foil, used for gasoline engines, and an EMS foil, used for diesel engines. The MK foil showed a percent weight gain of …

Determining A Method For Rendering Low Cost Cdse(Zns) Core(Shell) Quantum Dots Aqueous Soluble Via Amphiphilic Polymer Wrapping, Patrick Mcbride

Materials Engineering

Herein is described the procedure of two amphiphilic polymer wrapping techniques that may be employed for obtaining aqueous soluble quantum dots (QDs) for use in biological fluorescent imaging applications. The advent of QDs has led to new nanoscale fluorescent materials that exhibit unparalleled quantum yields (QYs), high resistance to photobleaching, tunable emissions, and
absorption over a large optical range. However, the QD synthesis employed here at Cal Poly to obtain bright, photostable CdSe(ZnS) core(shell) QDs involves the use of organic solvents and surfactants, leading to hydrophobic QDs. Since all of biology relies on aqueous solubility, this hydrophobicity creates a major …

The Effects Of Colorant Oxides And Firing Rate On The Nucleation And Growth Of Zinc Silicate Crystals In Crystalline Glazes, Nicolas Coffey

Materials Engineering

This study looked at the effects of colorant oxides and firing rate on the nucleation and growth of crystals in zinc-based crystalline glazes. One weight percent of iron and copper oxide powders were mixed separately with a zinc-based crystalline glaze. The uncolored glaze along with both colored glazes were applied to test tiles and fired. Two different firing schedules were used with different ramp up firing rates of 165°C/hr (slow) and 205°C/hr (fast). X-ray diffraction (XRD) analysis found both zinc oxide and silica oxide in the raw glaze, which are the main components in the formation of zinc silicate. XRD …

Characterization Of A Pdms Microfluidic Reactor For Synthesizing Quantum Dots, Brian Harley

Materials Engineering

A PDMS microfluidic reactor was made in Cal Poly’s class 1000 clean room for the purpose of synthesizing quantum dots. The device master mold was made from a silicon substrate and SU-8 features 50μm tall. The PDMS reactor was cast from that mold. The flow rates of fluid through the channels, heating of the reactor and pressure in the reactor were measured in order to characterize the potential for synthesizing quantum dots. Flow rates of 20 mL/hr through 4 mL/hr were tested to characterize the consistency of amount of time the fluid remains in the reactor at a constant flow …

Migration Models - Comparison Of Pvc, Pet And Pla Diffusivity, Combined With A Production Cost Model For Westridge Laboratories, Shelley Cooke, Sarina Surrette

Materials Engineering

This project has two parts: [1] a migration and diffusivity model for candidate plastics used in containers, and [2] a product cost model for Westridge Laboratories (Santa Ana, CA).

Diffusion modeling is a useful tool to predict migration of polymer constituents into exposed liquids. Polyvinyl chloride (PVC), polyethylene terephthalate (PET) and polylactic acid (PLA) were studied to estimate production costs, and component migration into water-based liquids from plastic containers. Bis (2-ethylhexyl) phthalate (DEHP), antimony trioxide, and stannous octoate, are components of concern in the three candidate polymers, respectively. Normal detection limits for these constituents are about 1 - 10 ppb, …