Materials Science and Engineering Commons^™

Age Strengthening Of Gray Cast Iron: Alloying Effects And Kinetics Study, Thottathil Viswanathan Anish

Masters Theses

"Age strengthening of gray cast iron has become a critical issue with metal casters trying to optimize their process for the closest conformance to properties. This necessitated more robust and precise methods to predict age strengthening. Most foundries use age strengthening behavior to cast at hight carbon equivalents to facilitate smaller gating systems. Also, it is well known in the casting industry that the tool life improves with aging. Hence these foundries require a model to predict aging behavior and accelerate the mechanism from days to hours. This research focuses on the methods of composition adjustments to control aging properties, …

Direct Microstructure Deposition By Micromirror Direct Patterning And Laser Sintering Of Nanoparticles, Weiya Fang

Masters Theses

"The emerging demand for low cost, medium volume production and flexible micro-fabrication techniques has been advanced by the development of MEMS and limitations of the existing technique. As a promising building block for future MEMS and IC industry, nanoparticles are attracting more and more attention due to their interesting electronic, catalytic and optical properties, which can be finely tuned by varying their size. A novel process for the manufacturing of functional microstructures by modulated laser direct patterning and curing of nanoparticles is presented.

The first part of the thesis aims to understand the possibility and process of using modulated laser …

Microwave Pretreatment Of Corn Stover For Anaerobic Digestion, Abhishek D. Saxena

Masters Theses

Anaerobic digestion is one of the several technologies used for biomass conversion to electricity or heat. This thesis focused on microwave irradiation of corn stover as a pretreatment for anaerobic digestion, and studies its impact on methane production.

The first run comprised three sets of stover soaked overnight in water, dilute sulfuric acid and dilute acetic acid, and each treated to three different levels of microwave irradiation. The results indicated a high variability in the data of the water set, which showed that there was no clear impact of microwave pretreatment on methane production. The dilute sulfuric acid and dilute …

Investigation Of Electrical Properties And Structure Of Vacuum Evaporated C60 Films, Angiras D. Pandya

Masters Theses

C₆₀ is an important electronic material and its properties can be tuned by thermal annealing process and solid phase crystallization process. These properties were investigated as a function of thermal annealing temperature and solid phase crystallization. However there is no systematical study on annealing effect and Solid Phase Crystallization of C₆₀ films. In this study, the effect of thermal annealing on formation of nanocrystalline C₆₀ thin films were investigated for annealed samples and solid phase crystallized samples. The C₆₀ films described here were prepared by vacuum thermal evaporation method. The structural properties of C₆₀ films …

Hot Melt Inks For Rotogravure-Formulation, Printability And Rheology, Hrishikesh Shreeram Bhide

Masters Theses

A new generation of "Hot melt inks for Rotogravure" was formulated. They melt during heating and reach printable viscosity between 75° C and 130° C, depending on formulation. After printing onto substrate, they solidify. Selections of the best formulations were done based on ink rheology, and print analysis. The formulated inks were also printed on the Moser sheet-fed proofing press .. The rheological data indicated that hot melt inks (without viscosity modifier) have viscosity in the range of 10°-10¹ Poise at 95°C. After printed on a laboratory gravure K-Proofer, the inks showed good reflective density (0.90 - Yellow, 1.30 …

The Effect Of Non-Stoichiometry On The Structure Of La-Ni And La-Ni-Ga Alloys, Pertrice Auguste Wethey

Masters Theses

Non-stoichiometric samples of the AB₅ system defined by the formula La_1-yNi_5+2y and LaNi_5+2xGa_1-x were cast using an arc-melting furnace. The samples were then analyzed to determine their lattice parameters and phases present using XRD. They were then heat-treated to produce homogeneous compounds and quenched with the intention of retaining high temperature compositions. Following the heat-treatment, the alloys underwent XRD again as well as SEM/EDS. The XRD information was analyzed using Rietveld refinement and the elemental data derived from the EDS was used to ascertain the compositions were statistically akin to the weighed values. …

Texture And Residual Stresses On Nanocomposite Coatings, Hussam E. Aikhasawneh

Masters Theses

Nickel was electroplated on cold-rolled 2024-T3 aluminum. The coating was done with reinforcement by nanoparticles of y-alumina or silicon carbide. For comparison, nickel-only coatings were done too. Rectangular samples were coated in nickel sulfamate bath with no particles to determine the optimum coating conditions. The optimized parameters were the current density, time of coating, and agitation rate. After coating conditions were established, composite samples were coated using these conditions. The coated layer was characterized by measuring: thickness, residual stresses, and crystallographic preferred orientation. The coated layer was tested by SEM for evaluation of the quality of the coatings. The presence …

Effect Of Modified Clay-Zeolite Pigment On The Viscoelastic, Optical, And Printing Properties Of A Lwc Gravure Coating, Lokendra Pal

Masters Theses

This study investigates the influence of modified clay- zeolite pigment on the viscoelastic, optical, and printing properties of a LWC coating. Currently, lightweight, coated papers have experienced problems with mottle, distortion, fiber puffing and poor print quality when printed with water-based inks. However, water-based inks represent a proven solution to reducing volatile organic compound (VOCs) emissions. Poor wetting and ink spreading on the paper surface constitute the majority of print quality issues associated with the water-based printing of LWC papers.

Similar problems are encountered during the printing of ink jet papers due to high percentage of water contained in these …

Metastable Phases Of Mgo-Tio2 Solid Solutions, Liang-Chieh Ma

Masters Theses

Magnesium titanium oxide powders were synthesized by the sol-gel method using alkoxides of magnesium and titanium with different ratios. Matastable phases of qandilite, Mg₂TiO₄, were found with Mg:Ti ratios down to 1.52:1 in lower temperature 600 °C than in the equilibrium condition which is above 1200 °C. Powder samples were examined by neutron powder diffraction and X-ray photoelectron spectroscopy (XPS) for analysis of structure and oxidation states. Also, samples were tested for the Mg:Ti ratios by induced coupled plasma atomic emission spectrometry. The structure refinements of the samples were done by General Structure Analysis System (GSAS) …

Development Of Water-Based Ink System For Braille Printing, Saurabh Varma

Masters Theses

The most commonly used system of writing by and for blind persons is called Braille, named after its French inventor, Louis Braille (1809-1952). Braille is comprised of a rectangular six-dot cell on its end, with up to 63 possible combinations using one or more of the six dots. Braille is the only reliable method of literacy for blind persons, because it enables them to read and write by touch¹.

Currently, Braille is printed by special embossers that serve as a printing press. These embossers create Braille output when it is attached appropriately to computers. The speed of these …

Iron Phosphate Glass For The Vitrification Of Ineel Sodium Bearing Waste And Hanford Low Activity Waste, Robert Douglas Leerssen

Masters Theses

"The current study investigates the feasibility of using iron phosphate glass for the immobilization of nuclear wastes that have limited solubility in the current borosilicate glass used for vitrification. These wastes contain elements such as sulfur and phosphorus, which have proven problematic (causing phase separation at >1 wt%) for vitrification in borosilicate glasses, as well as having a high soda content (50-75 wt%) which also limits wasteloading"--Abstract, page iv.

Lateral Migration Of A Solid Particle In Shear Flow, Wutthapong Jiraporncharoen

Masters Theses

Lateral migration of solid particles in shear flow is observed in various industrial applications. Suspensions in a blade coater, a device used to apply coating pigment to a base paper to improve paper properties, is an example. Particle hydrodynamics will affect the quality of coated paper and runnability of the coater especially when the speed of the coating machine is very high or the pigment concentration is increased.

Many factors will affect the particle migration. The wall repulsion or lubrication effect forces the particle away from a wall to the channel center. The inertial effects are increased by increasing the …

Effects Of Compression Processing Parameters And Antioxidants On Molecular Degradation Of Biodegradable Poly-L-Lactide (Plla), Thomas J. Hannan Jr.

Masters Theses

The purpose of this research was to find a combination of poly (L-lactic acid), also known as poly-L-lactide or (PLLA) and antioxidants that would, together, produce a product whose degradation rate would be advantageous for use in biodegradable medical implants. Intrinsic viscosity tests were conducted on compression molded samples of PLLA that were molded at various processing parameters in order to find optimal parameters. The optimal processing parameters were found to be time 10 minutes, temperature 220°C, and pressure 1000 psi.

The molecular weight of PLLA sample was taken while pressure, time, and temperature were varied. As pressure increased, no …

Effect Of Antioxidants On Ultra High Molecular Weight Polyethylene (Uhmwpe), Clifford Schrader

Masters Theses

This thesis presents a study on the effects of antioxidants on the oxidative induction time (OIT), thermal behavior, and hardness property of ultra high molecular weight polyethylene (UHMWPE). The antioxidants were dissolved into methanol alcohol before the solution was mixed with UHMWPE powder. The mixture was degassed under vacuum, and then compression-molded into disks 1.25 in. in diameter.

Different antioxidants were evaluated at concentrations up to 0.6 percent. A 0.6 percent concentration was used to screen the effectiveness of various antioxidants. Effect of antioxidant concentration was investigated in the range between 0 and 0.6 percent. OIT was evaluated on UHMWPE …

An Analysis Of Texture Resulting From Thermomechanical Processing Of Ti-6al-V, David J. Brock

Masters Theses

An investigation of texture and microstructure formation in Ti-6Al-4V after thermomechanical processing and heat treating was performed. X-ray diffraction was used to measure prismatic and pyramidal pole figures. These pole figures were used to calculate basal pole figures, which showed significant changes in texture from heavy rolling and near or above β-transus heat treatments. Primary texture components were found to be strengthened by near β-transus heat treatments. For heavily rolled material, above β-transus heat treatments were found to reverse the primary texture components order of dominants. Heavy rolling was found to reduce the RD component and strengthen the TD.

The Effects Of Machining On Structure And Tribological Properties Of Ultra High Molecular Weight Polyethylene For Artificial Joint Prostheses, Jinshan Song

Masters Theses

Understanding the effect of machining on the structure and property of subsurface layer of ultra high molecular weight polyethylene (UHMWPE) can significantly facilitate the increase in longevity of artificial joints. This study was performed to investigate the machining effects on the polymeric structure and tribological properties. Machining parameters include cutting speed, tool feed rate and depth of cut. Temperature rise was studied during machining to assess the extent of thermal degradation due to machining. Polymeric structure of the semicrystalline polymer was characterized using differential scanning calorimetry (DSC) in terms of melting enthalpy, crystallinity and melting temperature. Surface texture and hardness …

Mechanical And Tribological Properties Of Composites Of Recycled High Density Polyethylene And Recycled Rubber, Jason G. Boulanger

Masters Theses

This thesis presents a study on the mechanical and tribological properties of composite materials of recycled high density polyethylene (HDPE) and recycled rubber tire particles. The materials were compounded by extrusion and formed into test specimens by injection molding.

The first experiment studied the effect of recycled rubber percentage on mechanical properties of composites of recycled HDPE and recycled rubber. The mechanical properties included tensile strength, percent elongation, hardness, and impact resistance. Recycled rubber concentrations of 0, 5, 10, 15, 20, 25, and 30 percent were tested. The second experiment investigated the tribological properties of recycled HDPE and recycled rubber …

Study On Rheological Behavior Of The Composites Of Recycled Hdpe With Recycled Tire Rubber Particles, Yanze Li

Masters Theses

This study was mainly concerned with rheological properties of composites of recycled high density polyethylene (HDPE) with recycled tire rubber particles at shear rates from 1.167 to 116.7 s^-1. The viscosity was investigated in terms of effects of shear rate, shear stress, temperature, concentration of recycled tire rubber particles and heating duration. The temperature was in the range from 160 to 250 °C and the rubber particle concentration was between 0 and 25%. The heat duration for the composites was up to 240 minutes before testing.

The viscosities of composites were decreased with increase in shear rate and …

Thermoplastic Composites Of Recycled High Density Polyethylene And Recycled Tire Particles, James N. Mckirahan Jr.

Masters Theses

This study identified the mechanical properties and processibility of composite materials of recycled high density polyethylene (HDPE), recycled rubber tire particles, and/or ethyl co-vinyl acetate and poly (e-caprolactone). The composites were processed using a single screw extrusion system.

Three groups of experiments were conducted, on the composites in their extruded form to investigate the mechanical properties of ultimate tensile strength, percent elongation, and hardness. The first experiment investigated the effect of recycled rubber particle concentration in the composites up to 25 percent. The second experiment investigated the effect of recycled rubber particle size on the composites of recycled HDPE and …

Iron Phosphate Glasses As A Potential Nuclear Waste Disposal Medium, Melissa G. Mesko

Masters Theses

”Phosphate glasses containing large amounts of Fe₂O₃ (up to 43wt%) were studied to determine their potential suitability as nuclear waste disposal glasses for high level radioactive wastes containing large concentrations of iron oxide, phosphate, and fluoride compounds. Glass formation and chemical durability was the prime focus of this study, while properties such as density, thermal expansion, dilatometric softening temperature, and devitrification temperature were examined as well. It was found that large amounts of simulated nuclear waste material (up to 44.4wt% Cs₂O or 37.5wt% SrO) could be incorporated into the base iron phosphate glass while retaining …

Nonlinear Finite Element Micromechanic Analysis Of Thermoplastic Composite Of Recycled High Density Polyethylene Reinforced With Short Glass Fibers, Qiming Lou

Masters Theses

This thesis studied the nonlinear micromechanic behavior of thermoplastic composite of recycled high density polyethylene (HDPE) reinforced with short glass fibers using finite element method. The composite material was modeled using a micromechanic unit cell to simulate the stress distribution between the plastic matrix and the fiber in the composite. Nonlinear behavior of recycled HDPE and imperfect bonding between the fiber and matrix were investigated. Load-bearing capability of the fiber was evaluated using stress partition ratio (SPR) in the composite models. The effect of fiber aspect ratio on the stress distribution of the composite was studied to optimize the material …

Effect Of Poly Acrylate Addition On Coating Color Rheology, Water Retention And Coating Performance, Shambhu Nath

Masters Theses

Five polyacrylate samples were used to study their effects on coating color rheology, water holding and runnability. The Cylindrical Laboratory Coater was used to apply the coatings and study the runnability of the coating colors. The healing tendencies of the coatings were studied by inducing a scratch under the blade. The higher acid level and degree of crosslinking of the polyacrylate gave higher viscosity and the higher acid level also gave higher water retention. Coating colors containing polyacrylates were less prone to dilatancy at high shear. The addition of polyacrylate reduced the healing of coating colors, but for the same …

An Investigation Of Recycled High Density Polyethylene Reinforced By Short Glass Fibers, Tony Lynn Alwardt

Masters Theses

The mechanical properties of recycled high density polyethylene (HDPE) reinforced by short glass fibers were investigated. The composites formed by an injection molding process were examined in terms of tensile strength, percent elongation, and hardness. Recycled HDPE was compared to virgin HDPE regarding the effects of fiber concentrations, types, sizes, and treatments. The addition of three coupling agents at different concentrations was investigated.

The virgin HDPE composites slightly outperformed their recycled HDPE counterparts; having higher tensile strength and hardness, but were less ductile. Increase in fiber concentration generally increased the tensile strength and hardness, but the concentration of fibers was …

Silicon Carbide/Electroless Nickel Composite Plating For Aluminum Substrates, Ben Charbit

Masters Theses

The effectiveness of producing a composite coating by suspending micron-sized particles in an electroless nickel bath while plating a 2024T4 aluminum alloy part was studied. The variation in the count of particles trapped in the nickel coating due to changes in the particle size, concentration of the particles in the bath, and the substrate surface texture was also studied. Particle sizes of 1 micron and 10 microns, concentrations of 15 gr/lt and 30 gr/lt, and polished and blasted textures were used. It was found that this technique is an effective way to produce composite coatings rendering a high number of …

Prediction Of Paper Color: A Process Simulation Approach, Mayank Chaturvedi

Masters Theses

A simulation model was developed for a dye mixing process and for the prediction of the optical properties of the paper. The model was integrated with the MAPPS (Modular Analysis of Pulp and Paper Systems) simulation software package. The model was validated using dyed handsheets made in a laboratory and dyed paper made on a pilot papermachine. Validation comprised of prediction of the optical properties of the handsheets and the machine-made paper which contained various combinations of three non-fluorescent dyes. Sheet reflectances were predicted at 20 nanometer intervals for discrete light wavelength range of 400 to 700 nanometers and verified …

Optimization Of Sodium Carbonate-Sodium Hydroxide Pulping Of Wheat Straw For Corrugating Medium Production, Irmak Yayin

Masters Theses

This study's primary objective was to present sodium carbonate pulping as an alternative to soda or lime pulping of wheat straw for corrugating medium production. If sodium carbonate pulping is comparable with soda pulping in terms of strength properties, it could be the preference of choice because the recovery of sodium carbonate is simpler requiring less capital investment. The two strength properties that were optimized with respect to total chemical charge, cooking time, and sodium hydroxide fraction in the cooking liquor were Concora crush resistance and STFI compressive strength. These are the two most important strength properties for the end …

An Experimental Investigation Of Bevelled Blade Coating For Paper, Mustafa Naci Altug

Masters Theses

In this study the total dynamic force (TDF) acting on the blade was determined at three different web speeds. The objective was to compare quantitatively the experimental results with the predictions of existing models to show whether or not any of these models predict coat weight development. The existing models include the lubrication theory, impact model, lateral force, and combinations of these models.

Under the conditions investigated, the estimated TDF was in good agreement only with the impact force (sum of impulse and hydrodynamic forces) model of blade coating. The impulse force accounted for 94% of the TDF and, therefore, …

Microstructural Characterization Of Rapidly Solidified And Extruded Ti-Al-Nb Alloys, Danny Joe Edwards

Masters Theses

"Two titanium alloys have been characterized using transmission and scanning electron microscopy, X-ray diffraction, and optical metallography techniques. Both of these alloys were rapidly solidified by melt spinning, the resulting ribbons pulverized, and the powders then extruded into cylindrical billets. The alloys are based on the compositions Ti-21.3Al- 9 Nb-0.6-Mo-2.6V and Ti-13.2Al-2.6Nb-0.5Mo-0.9V-0.5Zr-3.1B in atomic percent. The first alloy was examined in both the as-extruded condition and in the annealed condition (looo0c for 12 hours). The second alloy was examined in the as-extruded condition only.

For the first alloy, the as-extruded microstructure consisted of a B2 matrix with alpha-2 particles at …

Fluid Dynamics Of An Atomizer Nozzle, Bhaskar Sengupta

Masters Theses

"A pilot plant gas atomizer was designed and assembled at the Center of Pyrometallurgy, U.M.R., to produce metal powders. The pilot plant utilizes a confined, annular, supersonic nozzle to yield spherical metal powders (aluminum and zinc alloys have been atomized) of average size of 15μm in diameter.

A cold model of the atomizing nozzle was constructed to simulate the pilot plant. First, the high-speed gas flow was studied and later, modelling of the atomizing process was carried out by using water as the atomized liquid. This work has investigated the complex gas flow in the converging-diverging nozzle and around the …

The Relationship Of Pore Volume And Pore Size Distribution To The Development Of Gloss And Scattering Coefficient, John A. Cook

Masters Theses

This study describes in a quantitative manner the relationships between coating structure and optical properties. Gloss, scattering coefficient and void volume were measured after applying different blends of polystyrene spheres to mylar film. Each coating was modeled using large spherical particles of the same size ratios to measure pore size distribution. The coating structure followed well with theoretical packing characteristics of spheres. Optical properties were related to changes in coating structure. Scattering coefficient and gloss correlated better with pore size distribution than particle size. Gloss increased when total void volume was reduced, while the scattering coefficient decreased.