Engineering Commons^™

Preparation And Characterization Of Eva/Cort Microparticles For Rattlesnake Endocrinology Studies, Alexander C. Pauer

Materials Engineering

No abstract provided.

Analysis Of The Low-Cycle Fatigue Behavior Of Silicone Rubber For Biomedical Balloons, Chase Cooper

Materials Engineering

The development of a medical drug delivery device that allows for the deployment drugs into the adventitial tissue of blood vessels requires the inflation of a silicone elastomer. The inflated silicone must be able to consistently endure multiple loading cycles without failing so that the device can operate reliably. There are multiple methods of processing the silicone for the device and the goal of this study is to examine the effect of the various processing methods on the characteristics of the silicone. The Dynamic Mechanical Analysis Machine (DMA) is used to model the conditions of the device’s application by performing …

The Relationship Between Structural Parameters And Mechanical Properties Of Cactus Spines, Jorge Armando Martinez, Pamela Liz Szeto, Theresa Mae Stewart

Materials Engineering

Considering an increasing interest in renewable, biodegradable resources that exhibit excellent mechanical properties, 24 species of cactus spines were investigated using three-point bend testing, X-ray diffraction (XRD) for structural parameters, and scanning electron microscopy (SEM) to analyze fracture surfaces. Additionally, a density of about 1.3 g/cm3 was measured for each spine utilizing the displacement method, closely matching existing data from literature. The flexural modulus varied greatly between species, ranging from 1.22 GPa (Echinocactus polycephalus) to 43.58 GPa (Stenocereus thurberi). In addition, flexural strength and strain to failure was also measured for each spine. XRD analysis of …

Selective Depolymerization Of Industrial Hemp And Its Effects On Thermal Resistivity, Tanner J. Jolly

Materials Engineering

There is a growing shift within the construction materials industry towards green and sustainable building products. Spending in this area has increased 5 fold since 2011 to a total revenue of $70 billion. An area of particular interest has been aimed at replacing fiberglass batt insulation with cellulose. Cellulose is the most abundant polymer on earth, and has potential to replace petroleum derived insulations. This project explores the potential of selectively isolating cellulose by depolymerizing the support structures found in lignocellulosic materials – specifically lignin and hemicellulose. The current focus is on isolating cellulose from Cannibas sativa, but more …

Effect Of Metal Organic Framework Concentration On The Crystallization Of Pla-Al-Mof Composites, Eric Futak, Jeffrey Norton, Jessie O'Connell, Nestor Vazquez

Materials Engineering

Poly(lactic acid) (PLA), a well-known biopolymer, is lacking in barrier properties and toughness. The research goal of this project is to look at the crystallinity of PLA when combined with metal organic framework (MOF). It is speculated that MOF has an effect on PLA chain mobility, and therefore crystallinity. In this study, aluminum MOF was added to PLA in varying concentrations (0, 0.5, 1, 2, 5, 10, and 20 wt%) to observe the crystallinity of the composite. The resulting PLA-Al-MOF composite films were characterized using differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron …

Manufacturing And Characterization Of Poly (Lactic Acid)/Carbon Black Conductive Composites For Fdm Feedstock: An Exploratory Study, Dylan Fitz-Gerald, Justin Boothe

Materials Engineering

This exploratory study developed methods of manufacturing and characterizing the electrical properties of small batches of conductive composite feedstock for the Fused Deposition Modeling (FDM) manufacturing process, commonly known as 3D printing. We utilized a solution casting process of Poly(lactic acid) (PLA) (Grade 4043D, NatureWorks, LLC.) and Carbon Black (CB) (Vulcan® XC72, Cabot Corp.) in chloroform. The resulting composite precursor was cryogenically treated with liquid nitrogen and milled in a coffee grinder in order to achieve particles that could be fed into the extruder. Composite precursors were dried in a vacuum oven at an elevated temperature of 38°C. Filaments were …

Solution Casting And Mechanical Testing Of Arabinan-Cellulose Nanocomposites, Kevin Su, Alina Lusebrink

Materials Engineering

The purpose of this work was to investigate methods to produce consistent, reliable, and testable thin films of arabinan-cellulose nanocomposites. Mechanical properties and composition of the Opuntia ficus-indica cactus spines served as motivation for this research. The high specific strength and stiffness, biodegradability, and sustainability of these spines inspired the creation of composites fabricated from the same materials found in cactus spines: arabinan and nanocrystalline cellulose (NCC). Arabinan serves as the matrix material and NCC as the reinforcement. To explore the feasibility of using a non-toxic solvent, different solution casting techniques with water as a solvent were investigated. Ultrasonication was …

Molecular Dynamics Investigation Of The Arabinan-Cellulose Interface For Cellulose Nanocomposite Applications, Luke Thornley

Materials Engineering

Atom level computer simulations of the arabinan and cellulose interface were performed to better understand the mechanisms that give arabinan-cellulose composites (ArCCs) their strength with the goal to improve man-made ArCCs. The molecular dynamics (MD) software LAMMPS was used in conjunction with the ReaxFF/c force field to model the bond between cellulose and arabinan. A cellulose nanocrystal with dimensions 51 x 32 x 8 Å was minimized with various weight percent of water, 0%, 3%, 5%, 8%, 10%, and 12%. After the system was equilibrated for at least 100,000 femtoseconds, an arabinan molecule composed of 8 arabinose rings was added …

Effect Of Heat Treatment On The Mechanical Properties In Natural Bamboo, Austin Levy, Mackenzie Kirkpatrick

Materials Engineering

Previous studies have shown that heat treatments have the ability to improve mechanical strength and stiffness in hardwood species. Compared to structural hardwoods, bamboo is a more sustainable and globally viable renewable resource. Therefore, Bambusoides vivax (timber bamboo) culms were fabricated into flat, rectangular cross-section samples with varying cellulose content to be heat treated and tested for mechanical properties. All samples were heat treated (HT) twice. The first HT was a normalization of all samples at 103 +/- 3 °C. The second HT was performed at various times and temperatures ranging from 130°C to 170°C for 0.5 to 3 hours. …

Effect Of Time Delay Between Etching And Adhesive Bonding (“Outlife” Time) On Lap-Shear Strength Of Aluminum Alloys Using Environmentally-Friendly P2 Etch, Josh Barkhimer, Matthew Erich, Gokul Nair

Materials Engineering

Raytheon Company currently uses a Forest Products Laboratory (FPL) paste etchant for preparing aluminum surfaces for adhesive bonding, and FPL is a source of hazardous hexavalent chromium. The goal of this study was to evaluate a less-toxic P2 paste etchant as a possible replacement. Coupons of 2024-T3, 6061-T6, and 7075-T6 grades of aluminum alloy were solvent-degreased, abrasively cleaned, and etched at room temperature using P2 paste following a strict protocol adopted from Raytheon. Coupons were then left exposed to air for assigned time intervals (or “outlife” times) of 0, 1, 4, 8, 16, and 63 or 72 hours. The aluminum …

Minimizing Sheet Resistance Of Organic Photovoltaic Cell Top Contact Electrode Layer: Silver Nanowire Concentration Vs. Conductive Polymer Doping Concentration, Caitlyn Cook

Materials Engineering

The top contact electrode layers of nine organic photovoltaic cells were prepared with two varying factors: three Silver nanowire (AgNW) densities deposited on a conductive polymer doped with three concentrations. Silver’s low sheet resistance of 20-Ω/sq is hypothesized to lower the sheet resistance of the anode layer and thus enhance the overall efficiency of the cell. Four-point probe measurements indicated that increasing AgNW density in the top contact electrode layer of an organic photovoltaic cell significantly reduces sheet resistance from 52.2k-Ω/sq to 18.0 Ω/sq. Although an increase in doping concentration of the conductive polymer reduced sheet resistance in low AgNW …

Prediction Of Tribological Behavior Of Candidate Materials For Rotor Seals, John W. Franzino, Will F. Michul

Materials Engineering

To reduce high costs associated with manufacturing and testing materials for rotor seals, a procedure needs to be developed to quickly and accurately test candidate materials as they are released. The test should reduce the amount of fabrication required and model working conditions in order to accurately assess the tribological behavior of candidate materials. A possible solution was examined that utilized a rig meant to model operational stresses and wear. Compression modulus data was then taken in order to quantify the accumulation of damage due to microcracking, the primary mode of failure, through a damage index parameter. Testing results concluded …

Mechanical Behavior Of Compression Molded Polyethylene Terephthalate, Daniel Cole Greinke, Paul Jackson Mcewan, Dan Tran

Materials Engineering

The purpose of this project was to investigate the effects of time, temperature, and pressure on the tensile strength and elastic modulus of recycled PET. Compression molding trials were performed on shredded PET bottles to produce tensile test specimens conforming to ASTM D638-03. Aluminum molds containing the PET were mechanically fastened together at the desired pressure and heated in an electric oven. The resulting specimens were subjected to tensile testing for analysis. This screening experiment failed to generate any statistically significant data concerning the factors of interest. These preliminary results may be used to design a more systematic follow-up study.

Characterization Of A Thin Film Composite Membrane: Fluorinated Copolymer In A Carbon Nanotube Matrix, Eric P. Bonaventure, Michael A. Brew, Cynthia R. Shannon

Materials Engineering

IDEX Health and Science has created a thin-film composite membrane consisting of a carbon nanotube matrix impregnated with a fluorinated copolymer called Teflon® AF 2400. This membrane is being studied for use in degassing chambers of analytical instruments such as a High Pressure Liquid Chromatography (HPLC) degassing modules. The level of impregnation of the Teflon® in the carbon matrix affects the diffusion properties which are crucial for the performance of the membrane. Scanning Electron Microscopy (SEM) characterization techniques were used to measure the outer Teflon® and the inner carbon matrix layer thickness. The outer Teflon® and inner carbon matrix layer …

Manufacture And Mechanical Testing Of Thin Film Composites Composed Of Poly-Lactic Acid And Nanocrystalline Cellulose, Catherine E. Mohan

Materials Engineering

Society’s overuse of petroleum-based plastic products has created a waste problem that is threatening environments around the world. New efforts have been made to find a suitable replacement derived from a renewable source. Poly-lactic acid has become one of the front-runners in this search. It is derived from starches found in potatoes, corn, and other grains. There are many factors that make Poly-lactic acid-based polymers a suitable replacement for petroleum-based ones, but it still suffers from low mechanical strength due to low crystallinity percentages. Doping the polymer with nanocrystalline cellulose provides more nucleation sites for the crystallization of the polymer …

Low Velocity Impact Tower Feasibility, Setup, And Impact Testing Of Carbon Fiber Reinforced Epoxy Thermoset And Peek Thermoplastic Matrix Composites, Brent Plehn

Materials Engineering

A low velocity impact tower was donated to Cal Poly's Materials Engineering Department along with four fiber reinforced polymer matrix composites. The tower was set up in building 192 in the Mechanical Testing Laboratory. Improvements were made to the tower including adding velocity detection capabilities, making loose hardware inclusive, adding an extra tower arm for better consistency, adding a double jawed clamp for faster testing, and rerouting the tower's compressed air system to improve performance. A standard operating procedure was drafted, tested, and redrafted for impact testing composite panels. The four composite panels consisted of two quasi-isotropic 16 ply AS-1 …

Strength Testing And Material Characterization Of Cactus Spines, Mary Cooper, Jeff Goldstein, Thomas Tarlton

Materials Engineering

Twelve different species of cactus spines from 6 different genera were collected from living specimens and maintained in a dry storage environment. Spines from each species underwent 3-point bend testing, XRD testing, and SEM imaging. XRD analysis was used to verify the presence of cellulose whisker like nanocrystals and to calculate the percent crystallinity of each spine. SEM images were captured of fracture surfaces at viewing angles of 90° and 45° relative to the fracture surface, with magnifications ranging between 150x and 4,000x. A total of six spines from each species were tested in three point bending using a high-resolution …

An Investigation Of Arabinan And Cellulose Based Nano-Composite Fabrication Methods, Marianne Smithfield, Carl Petterson, Robert Miller

Materials Engineering

Microcrystalline cellulose was converted into nanocrystalline cellulose via an acid hydrolysis procedure. Scanning electron microscopy (SEM) was employed to measure the particle size and thus the effectiveness of acid hydrolysis. The nanocrystalline cellulose was poured through a 0.2μm filter to isolate the particles of ideal size. The nanocrystalline cellulose samples were stored in dimethylformamide (DMF) to prevent mold growth and agglomeration upon drying. Numerous composite samples were created by dissolving the arabinan in a solvent, suspending cellulose in the arabinan solution, and then drying the sample. Casting was performed in a silicon mold to allow sample removal without damage. Initial …

Evaluation Of Corrosion Properties Of Proprietary Metal Alloy Stents For In-Vivo Use, Michael David Bremner

Materials Engineering

To assess corrosion rates of metal alloy bio-absorbable stents an experimental set-up was designed to mimic the coronary artery environment. The artery was modeled using 4mm diameter Tecoflex tubing and the metal alloy stents were inserted into the tubing using a catheter. As is the case in cardiac surgery, the catheter with the stent and a microballoon were maneuvered to the desired position. The microballoon was then slowly inflated to expand the stent and compress it against the tubing walls. The catheter and microballoon were then withdrawn. A circulating pump system was set up to cycle fetal bovine serum (FBS) …

Analyzing The Acoustical Properties Of Alternative Materials In Guitar Soundboards To Reduce Deforestation, Chris Dunn

Materials Engineering

To mitigate the effects of deforestation, man-made alternative materials were analyzed and tested for potential use in the soundboards of acoustic guitars. The materials evaluated included 0.06 in. foamed polycarbonate, 0.12 in. single-ply honeycomb fiberglass, and 0.04 in. epoxy fiberglass. The properties of Sitka spruce, the most common tonewood, were used as a benchmark. The Young’s modulus to density ratio found in Sitka spruce is relatively high, making its properties ideal for soundboard applications. Both Young’s modulus and density were necessary to calculate the acoustic constant of each material that was tested. The samples were subject to the impact of …

Preparation Of A Polylactic Acid With Hydroxyapatite Reinforcement Composite, Odessa N. Quezon

Materials Engineering

Biodegradable polymers are a prime material choice for temporary biomedical devices due to its ability to degrade into non-toxic products for their use in vivo. However, polylactic acid (PLA) by itself lacks the sufficient strength and stiffness to permit their use as its properties begin to decrease as the polymer degrades. To improve the polymer’s mechanical properties, hydroxyapatite (HA) will be added to the PLA solution to act as reinforcement. The chemical property, glass transition temperature of a polymer, also plays a key role in the mechanical properties of the polymer. PLA’s glass temperature is 130⁰F. A polymer that …

Design And Construction Of A Simulated Evaporative Heat Exchanger For Testing The Mitigation Effects Of Pipe Coatings On Mineral Scale Deposition, Taylor J. Anderson

Materials Engineering

The thermal efficiency of evaporative heat exchangers is diminishing due to mineral scale buildup on heat exchanger surfaces. A simulated evaporative heat exchanger was designed and constructed for testing the mitigation effects of polymer coatings on mineral scale deposition rates. The heat exchanger was designed to cool hot mud at 200°F using a cooling water supply with a calcium concentration of 1000 ppm. The system was constructed using 1.5-inch diameter polypropylene piping, a DIG Corporation drip irrigation system, a TotalPond 530 GPH pond pump, an Omega CSI32K miniature benchtop controller, Omega FWH321-020 high temperature heater tape, and fifteen copper pipe …

Comparison Of Polyurethane And Polysiloxane Coating Systems In Marine Environments, Jake Jarman, Jessica Salvatin

Materials Engineering

This project investigates the performance benefits of polysiloxane and polyurethane coating systems for corrosion protection in marine environments. PPG Industries Amercoat 450H and International Paint Interthane 990HS were the polyurethane topcoats tested. PPG Industries Ameron PSX 700 (New Blend) and International Paint Interfine 878 were the polysiloxane topcoats tested. Each coating was sprayed onto carbon steel panels that were prepared through hand blasting with glass beads. Scribed and unscribed panels were tested in a salt fog chamber for 1,200 hours according to ASTM Standard B0117-11 and in a UV/Humidifier for 1,650 hours according to ASTM Standard D4587-11. Panels were tested …

Lunalight - Bringing Light To The Expanding World, Gabriela M. Igel, Daniel J. Patrick, Kimberley M. Smith

Materials Engineering

The LunaLight, a solar rechargeable light and cell phone charger, addresses the lack of access to electricity faced by 1.4 billion of the world’s population (International Finance Corporation). The LunaTech team has developed a product that is bright, simple, compact, versatile and competitive with existing products. Through a partnership with the non-profit organization One Million Lights, LunaTech has improved a previous team’s design to address user feedback, concerns of durability, and manufacturability.

The LunaLight design includes a 5 component plastic housing held together by 4 screws, a surface mounted PCB, a lithium-ion (Li-Ion) battery, one high-brightness LED, a solar panel, …

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 …

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, …

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 …

Wireless Temperature Monitoring System For The Cal Poly Pilot Winery, Caitlin Devaney

Materials Engineering

This project, with an interdisciplinary group of two computer engineers and one materials engineer, was seeking to implement an automated temperature monitoring system which is affordable and easy to use, as well as adaptable to any arrangement and scale of a winemaker’s fermentation setup. My goal, as the materials engineer, was to design, fabricate, and test the enclosure, for the wireless nodes that are placed in the wine fermentation tanks, and the materials used for the node enclosure. For the enclosure of the system, materials selection was completed using CES software using limitations of only polymer materials which absorb less …

Effects Of Abrasive Particles On The Projected Fatigue Life Of Nylon Climbing Rope, Casey Johnson, Charlie Klonowski

Materials Engineering

When climbing rope is used outdoors, it is exposed to foreign particles such as sand and silt. These particles can potentially work their way through a rope’s sheath and damage the load bearing core decreasing the rope’s strength without exhibiting obvious wear. This project quantified the effect of abrasive particles on the fatigue life of nylon climbing rope. The experimental design involved 18 pieces of static nylon rope of kernmantle construction. 9 of these samples were heavy agitated in a slurry of water, silt, sand and soil, and left to sit for 24 hours. The remaining 9 samples were submerged …

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 …