Materials Science and Engineering Commons^™

Al2O3 Oxide Morphology For Two Fe-Cr-Al Stainless Steel Foils Used In Gasoline Engine Catalytic Converters, Jennifer Suiter

Materials Engineering

Corrugated 0.05 in thick strips of Fe-Cr-Al ferritic stainless steel samples with 4% and 6% aluminum were heat treated, and the resulting Al₂O₃ oxide was analyzed using SEM imaging. Three heat treatment cycles were carried out for each sample. The heat treatments were based on future metal-substrate catalytic converter processing prior to applying the washcoat Each heat treatment started with a 90 minute ramp from room temperature to 538°C and a 32.5 minute ramp from 538°C to 899°C. The three different dwell periods at 899°C were 4 hours, 6 hours, and taking a sample out every hour …

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 …

Finite Element Modeling Of Ballistic Impact On A Glass Fiber Composite Armor, Dan M. Davis

Master's Theses

Finite Element Modeling of Ballistic Impact on a Glass Fiber Composite Armor

Dan Davis

Experiments measuring the ballistic performance of a commercially available fiberglass armor plate were used to guide the development of constitutive laws for a finite element model of the impact. The test samples are commercially available armor panels, made from E-glass fiber reinforced polyester rated to NIJ level III. Quasi-static tensile tests were used to establish material properties of the test panels. These properties were then used to create models in the explicit finite element code LSDYNA.

Ballistic impact testing of the panels was conducted using a …

Multipolymer Interactions In Bulk Heterojunction Photovoltaic Devices, Grant Olson

Physics

Multipolymer photovoltaics, single layer devices made up of multiple photoactive polymers, can create organic photovoltaics (OPVs) with a wider spectral response than single polymer systems without the difficult fabrication of a tandem. Our group has successfully created multipolymer solar devices with 2% power conversion efficiency. We have analyzed the optical and electrical properties of these devices, and found that it may be possible for polymers to assist each other with charge extraction, though combining polymers disrupts single polymer crystallinity.

Creating A Solar Cell Array From A Single Silicon Wafer, Samyukta Gade, Roderick Marstell

Materials Engineering

Two different processes to create multi-celled solar panels from single wafers were made and implemented. To do this, the cells must not have a common ground, and both designs use different approaches to solve this problem. One utilizes a 2.9 µm deep n-type well within a 10.74 µm deep p-type well in an n-type wafer. There are two cells in series, which has a theoretical voltage of 1 V. The cells are connected in series with 1.9 µm thick gold traces. Any area that the gold is not in contact with the silicon has a .5 µm layer silicon dioxide …

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 …

Fabricating Replacement Glass Prisms For The Piedras Blancas Lighthouse, Daniel Garcken

Materials Engineering

The objective of this project was to design and create a process for manufacturing replacement glass prisms for the Piedras Blancas lighthouse and several other lighthouses nationwide. The prisms were designed to be in multiple metal arrays spread across the floor of the beacon room (the topmost room of the lighthouses). The prisms functioned to transmit extra, radiant light from the beacon light through the floor of the beacon room and disperse it into the maintenance room below. Using computer aided drafting (CAD) software, an original prism was measured and modeled; the corresponding mold was also modeled. G-codes for controlling …

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 …

Synthesis Of White Cadmium-Selenium Quantum Dots, Kyle Reilly

Materials Engineering

A process was developed for the synthesis of cadmium-selenium quantum dots that fluoresce at multiple wavelengths, giving a white color to the solution. The process involved making a selenium pre-cursor, then a cadmium precursor, then injecting the selenium precursor into the cadmium precursor and extracting a sample. Once the a repeatable process for synthesizing white quantum dots was developed, the absorption and fluorescence was measured and recorded over a period of two weeks. In the development of the process, the key variables were the temperature of the cadmium precursor and the time between injecting the selenium precursor and extracting the …

Characterization Of Positive Macrosegregation At The Subsurface Of Direct-Chill Cast 7050 Aluminum Forging Billets, Aaron Youril

Materials Engineering

Segregation of alloying elements during casting of forging billets may persist to the final forged component leading to unacceptable surface appearance. Determination of the elements or compounds that segregate is the essential first step to solving this problem. Differential Scanning Calorimetry (DSC) was used to determine a composition profile of the macrosegregation occurring at the subsurface of an as-cast 7050 aluminum alloy billet. Data collection was carried out by separating 10 to 20 mg samples from the outer centimeter along the radius of the billet, as well as samples from the bulk interior of the billet for comparison with the …

Analysis Of Failed Forging Saddling Mandrels And Process Improvements For Increased Mandrel Lifespan, Brock Costalupes

Materials Engineering

This project seeks to increase the lifespan of steel mandrels used by Schlosser Forge in the saddling process, which is part of the production of forged rings for the aerospace and power generation industries. All saddle mandrel samples were taken from used 4340 steel mandrels. Hardness profiles were measured across rectangular bars cut from the transverse direction of a completely fractured piece of a 7″ diameter mandrel. The hardness near one outer surface of the tested bar was 36 HRC and gradually decreased to 30.5 HRC at the opposite surface. Macroscopic examination of the primary fracture surface along with light …

Effect Of Heating Temperature, Heating Time And Initial Microstructure On Recrystallization Of Waspaloy During Heating For Forging, Marissa Hill

Materials Engineering

A fine, uniform grain size is required for creep limited Waspaloy in aircraft engine applications. Upon heating, Waspaloy does not always recrystallize in a uniform manner resulting in occasional large grains with a majority of the grains meeting the grain size requirements. Waspaloy’s microstructure was analyzed with different heat treatments and in the as-forged condition. The strengthening mechanism is the gamma prime phase. The gamma prime solvus temperature is 1908°F so the different heat treatments were determined around that temperature, as well as the forging temperature range of 1800-2150°F. At the 1850°F heat treatment, the microstructure recrystallized with small grains, …

Corrosion Of Stainless Steel 316l And Astm F75 Cobalt Chromium Alloy During Immersion Testing In Silver Salt Solutions, Meagan Higgins

Materials Engineering

This study evaluates the potential effects of silver salts on biocompatible metals used for prostheses during the chemical reduction process to produce a silver antimicrobial layer on the metal’s surface. Samples of two biocompatible metals were obtained: Stainless Steel 316L and ASTM F75 Cobalt Chromium Alloy. Three different silver salts were also acquired: silver nitrate, silver sulfadiazine, and silver chloride. Specimens of each metal were cut to size using a 4-1/2 inch aluminum oxide, 40 grit, cut off wheel for metal, attached to a Dewalt Angle Grinder. The biocompatible metal samples were then subject to either Solution 1, water with …

Novel Platform Development Using An Assembly Of Carbon Nanotube, Nanogold And Immobilized Rna Capture Element Towards Rapid, Selective Sensing Of Bacteria, Elizabeth I. Maurer, Kristen K. Comfort, Saber M. Hussain, John J. Schlager, Sharmila M. Mukhopadhyay

Chemical and Materials Engineering Faculty Publications

This study examines the creation of a nano-featured biosensor platform designed for the rapid and selective detection of the bacterium Escherichia coli. The foundation of this sensor is carbon nanotubes decorated with gold nanoparticles that are modified with a specific, surface adherent ribonucleic acid (RNA) sequence element. The multi-step sensor assembly was accomplished by growing carbon nanotubes on a graphite substrate, the direct synthesis of gold nanoparticles on the nanotube surface, and the attachment of thiolated RNA to the bound nanoparticles.

The application of the compounded nanomaterials for sensor development has the distinct advantage of retaining the electrical behavior …

Effect Of Fluxing Additive On Sintering Temperature, Microstructure And Properties Of Batio3, Yaseen Iqbal, Asad Jamal, Riaz Ullah, M. Naeem Khan, Rick Ubic

Materials Science and Engineering Faculty Publications and Presentations

Various fluxing materials are added to technical ceramics in an attempt to lower their sintering temperatures and make their processing economical. The effect of 0·3wt% Li₂CO₃ addition on the phase, microstructure, phase transition temperatures and dielectric properties of BaTiO₃ was investigated in the present study. The addition of 0·3wt% Li2CO₃ was observed to lower the optimum sintering temperature by ∼200^◦C with no second phase formation and cause a five-fold reduction in grain size. Rhombohedral-to-orthorhombic and tetragonal-to-cubic phase transitions at the expected temperatures were evident from the Raman spectra, but the orthorhombic-totetragonal phase transition …

Process Optimization For Friction-Stir-Welded Martensitic Steel, M. Ghosh, K. Kumar, R. S. Mishra

Materials Science and Engineering Faculty Research & Creative Works

Advanced high-strength M190 steel sheets were joined by friction-stir welding under different tool rotational and traversing speeds. the optical microstructure of the joints exhibited complete martensite and partial martensite at the weld nugget depending on the cooling rate during welding. the first heat-affected zone outside of the weld nugget revealed ferrite-pearlite phase aggregate, and the second heat-affected zone showed a tempered martensitic structure. the interplay of process variables in terms of peak temperature and cooling rate was studied to observe their effect on joint efficiency under shear testing. the peak hardness at weld nugget was close to the parent alloy …

The Case For Open Source Appropriate Technology, Joshua M. Pearce

Michigan Tech Publications, Part 1

Much of the widespread poverty, environmental desecration, and waste of human life seen around the globe could be prevented by known (to humanity as a whole) technologies, many of which are simply not available to those that need it. This lack of access to critical information for sustainable development is directly responsible for a morally and ethically unacceptable level of human suffering and death. A solution to this general problem is the concept of open source appropriate technology or OSAT, which refers to technologies that provide for sustainable development while being designed in the same fashion as free and open …

The Incorporation Of Electrohydrodynamics And Other Modifications Into A Dry Spinning Model To Develop A Theoretical Framework For Electrospinning, Yuki Imura

Dissertations

The objective of this research was the development of a mathematical model of the electrospinning process using dry spinning modeling principles as a basis. This model is directed at the identification of parameters which influence final fiber characteristics, e.g., solvent concentration, temperature, spin line tension, and electric field. Preliminary computer simulations were performed; however, the generated data was inconclusive and was determined to be due in part to the complexity of the modeled system and the subsequent computational difficulties encountered. Although a comprehensive computational model of the electrospinning process has not yet been demonstrated, the theoretical development that was undertaken …

Synthesis, Molecular And Solid State Structures, And Magnetic Properties Of Sandwich Lanthanide Phthalocyanines Lacking C-H Bonds, Wycliffe A. Graham

Dissertations

A new class of sandwich phthalocyanine (Pc) compounds without C-H bonds was synthesized and characterized. They are the bis[octakis(perfluoro i-C₃F₇) octakis(perfluoro)phthalocyaninato(2−)]M(III) complexes, formulated as (F₆₄Pc)₂MH, M = Tb, Dy, Lu, Y. Single molecular magnetic (SMM) behavior in the (F₆₄Pc)₂TbH and (F₆₄Pc)₂DyH complexes was confirmed through slowed relaxation response of their magnetization in an applied time varying magnetic field during alternating current (AC) magnetic testing in the range 2 - 50 K. The energy barrier to magnetic reversal, Δ = 215 cm^-1 and …

Rational Design Of Hydrogen-Free Catalytic Active Sites, Andrei Ioan Loas

Dissertations

Materials that are organic-based and exhibit oxidative catalytic activity, including free-radical pathways, while being refractory to the activated oxygen species are not known. The synthesis of several classes of such materials, their electronic and structural characterizations as well as catalytic properties are reported. Their rational molecular design and biologically inspired reactivity are based on enzymatic active sites, which are reengineered into robust metal-organic fluoroalkylated scaffolds that, for the first time, exhibit structural asymmetry and tunable π-π interactions both in solution and solid state. In these complexes, labile C-H bonds are replaced with chemically and thermally resistant C-F bonds to create …