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Articles 1 - 17 of 17
Full-Text Articles in Engineering
Effects Of Uv Exposure On The Thermo-Mechanical Properties Of Cactus Based Biopolymers, Madison Glozer, Megan Bolling, Addison Wolfson
Effects Of Uv Exposure On The Thermo-Mechanical Properties Of Cactus Based Biopolymers, Madison Glozer, Megan Bolling, Addison Wolfson
Materials Engineering
The viability of renewable biopolymers as sustainable alternatives to synthetic plastics is promising, however ultra-violet (UV) radiation can lead to premature degradation and reduction in the material’s performance. Biopolymers comprised of nopal cactus juice, animal protein, natural wax, and glycerin in differing percentages were studied to obtain thermo-mechanical data in relation to UV exposure. To quantify degradation, dynamic mechanical analysis, thermogravimetric analysis, differential scanning calorimetry, infrared spectroscopy, goniometry and gravimetric measurements were performed. Each formulation experienced mass loss as a result of UV exposure, which could be attributed to water evaporation. The thermogravimetric analysis indicated a reduction in the second …
Reducing Food And Packaging Waste Through Developing Edible Fruit Based Packaging Prototypes, Melanie Thatcher
Reducing Food And Packaging Waste Through Developing Edible Fruit Based Packaging Prototypes, Melanie Thatcher
Materials Engineering
Packaging is used to contain, preserve, protect, and advertise both manufactured and natural products. In 2013 it was reported that over thirty percent of solid waste in the United States was from packaging. One way to reduce the impact of packaging on the environment is to create a solution that is edible and sourced from a waste or secondary food product that is not currently being utilized. Food-contact packaging made from recycled materials must meet strict U.S. Food and Drug Administration (FDA) regulations to be utilized as raw material for packaging. Fruit pomace is a candidate material since it may …
Solution Casting And Mechanical Testing Of Arabinan-Cellulose Nanocomposites, Kevin Su, Alina Lusebrink
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
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 …
Investigating The Cause Of Unique Mechanical Behavior In Platinum Alloy Guidewire Tips, Evan Borgeson, Alfred Rosen
Investigating The Cause Of Unique Mechanical Behavior In Platinum Alloy Guidewire Tips, Evan Borgeson, Alfred Rosen
Materials Engineering
The platinum alloy used by Abbott Vascular in guidewire tips exhibits a yielding behavior characterized by an abrupt transition from elastic to plastic zones and high ductility. This yielding behavior was hypothesized to be a result of one of three structural phenomena: ordering, solute strain aging, or interstitial strain aging. To test for these strengthening mechanisms in the wire, X-ray diffraction analysis, heat treatments, and tensile testing were completed. The wire has a diameter of 0.0025 inches and was supplied in two forms, the final stress relieved state, and as-drawn from the production line. Heat treatments were performed at 130 …
Fabrication And Testing Of Arabinan Cellulose Nanocomposites, Ross Johnson, Austin Rosso, Nick Semansky
Fabrication And Testing Of Arabinan Cellulose Nanocomposites, Ross Johnson, Austin Rosso, Nick Semansky
Materials Engineering
Inspired by the structure and composition of cactus spines found in nature, arabinan-cellulose nanocomposites were fabricated into thin films and tested for mechanical stiffness. The composites consisted of varying amounts of nanocrystalline cellulose reinforcement suspended in an arabinan matrix. Both materials are polysaccharides and are known to be biodegradable and food safe. The thin film samples were tensile tested using a dynamic mechanical analysis machine both as-cast and after a heat-treatment. The heat treatment of the arabinan itself resulted in an order of magnitude increase in stiffness, while the cellulose reinforced composites increased roughly six fold. The arabinan-50 wt% cellulose …
Strength Testing And Material Characterization Of Cactus Spines, Mary Cooper, Jeff Goldstein, Thomas Tarlton
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
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 …
Development Of A High Precision Quantum Dot Synthysis Method Utilizing A Microfluidic Reactor And In-Line Fluorescence Cell, Harry Lafferty, Jonny Hoadley
Development Of A High Precision Quantum Dot Synthysis Method Utilizing A Microfluidic Reactor And In-Line Fluorescence Cell, Harry Lafferty, Jonny Hoadley
Materials Engineering
Quantum dots show great potential for use as spectral converters in solar cells, lighting applications and biological imaging. These applications require precise control of quantum dot size to maximize performance. The fluorescence profile of quantum dots in solution correlates directly with particle size. An alternative, high precision process was developed for the synthesis of cadmium-selenide quantum dots using a microfluidic reactor and fluorescence flow through cell. The process required creating separate cadmium and selenium precursors that were then mixed in a nitrogen environment at 17± 1°C. Using an NE-300® syringe pump, the solution was pumped through a microfluidic reactor …
The Characterization And Comparison Of Biochar Produced From A Decentralized Reactor Using Forced Air And Natural Draft Pyrolysis, Leah Herbert, Ian Hosek, Rishi Kripalani
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 …
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 …
Artificial Alveolar-Capillary Membrane On A Microchip, Keith Male
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 80oC. For the porous membrane, the PDMS was spun on at 6000rpm for 30 seconds using a spin coater to produce a membrane …
The Effects Of Concentration, Stir Rate, And Processing Temperature On The Iridescence Of Polymethyl Methacrylate Nanoparticles, David Baruela
The Effects Of Concentration, Stir Rate, And Processing Temperature On The Iridescence Of Polymethyl Methacrylate Nanoparticles, David Baruela
Materials Engineering
Synthetic opals were synthesized by creating polymethyl methacrylate (PMMA) nanospheres in order to determine which conditions would create the best iridescent samples. The factors affecting the iridescence were nanosphere concentration, stir rate, and processing temperature. PMMA solutions were made by adding 17 mg of granular azobis to a solution of 16 mL of distilled water with 3 mL of methyl methacrylate (MMA). The solution was stirred at different rates, slow and fast, and different temperatures, 70 °C and 90 °C, under a constant flow of nitrogen gas for 40 minutes until the polymerization reaction was complete. Glass substrates were prepared …
The Mitigation Of Eutrophication Using Microporous Polymer Membranes To Control Algae Growth, Christopher R. Riley
The Mitigation Of Eutrophication Using Microporous Polymer Membranes To Control Algae Growth, Christopher R. Riley
Materials Engineering
A system was designed to mitigate the accelerated process of anthropogenic eutrophication. This system aimed to contain Chlorella Vulgaris microalgae cells within an enclosed polymer membrane pouch while allowing for water and nutrients to diffuse through the pouch. As a test model, a 10 gallon aquarium was partitioned into three sections using polycarbonate membranes with 1 micron pore diameters. Each section was then gradually filled with a deionized water and Bristol solution recommended for microalgae growth. Phosphate and nitrate were added to Section A of the aquarium and allowed to diffuse throughout the tank. A water pump was used to …
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
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 …
Processing Pdms Gecko Tape Using Isopore Filters And Silicon Wafer Templates, Boris Luu
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 …
Determining A Method For Rendering Low Cost Cdse(Zns) Core(Shell) Quantum Dots Aqueous Soluble Via Amphiphilic Polymer Wrapping, Patrick Mcbride
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 …