Materials Science and Engineering Commons^™

Investing In Maine Research Infrastructure: Sustainable Forest Bioproducts, Michael Eckardt, Stephen Shaler, Hemant P. Pendse, Adriaan R. P. Van Heiningen, Robert G. Wagner

University of Maine Office of Research Administration: Grant Reports

The University of Maine, the University of Southern Maine, several baccalaureate institutions in the state, along with other federal, state and local public, private, and non-profit institutions will collaborate to create the Forest Bioproducts Research Institute (FBRI) at the University of Maine. The vision of the FBRI is to advance understanding about the scientific underpinnings, system behavior, and policy implications for the production of forest-based bioproducts that meet societal needs for materials, chemicals, and fuels in an economically and ecologically sustainable manner.

The research plans Integrate three themes. They are (1) forest sustainability modeling of life cycle assessment, (2) integrated …

Electrical Impedance Imaging Of Corrosion On A Partially Accessible 2-Dimensional Region, Court Hoang, Katherine Osenbach

Mathematical Sciences Technical Reports (MSTR)

In this paper we examine the inverse problem of determining the amount of corrosion on an inaccessible surface of a two-dimensional region. Using numerical methods, we develop an algorithm for approximating corrosion profile using measurements of electrical potential along the accessible portion of the region. We also evaluate the effect of error on the problem, address the issue of ill-posedness, and develop a method of regularization to correct for this error. An examination of solution uniqueness is also presented.

Preparation And Hydrogen Absorption/Desorption Of Nanoporous Palladium Thin Films, Wen-Chung Li, Thomas John Balk

Chemical and Materials Engineering Faculty Publications

Nanoporous Pd (np-Pd) was prepared by co-sputtering Pd-Ni alloy films onto Si substrates, followed by chemical dealloying with sulfuric acid. X-ray diffractometry and chemical analysis were used to track the extent of dealloying. The np-Pd structure was changed from particle-like to sponge-like by diluting the sulfuric acid etchant. Using suitable precursor alloy composition and dealloying conditions, np-Pd films were prepared with uniform and open sponge-like structures, with interconnected ligaments and no cracks, yielding a large amount of surface area for reactions with hydrogen. Np-Pd films exhibited shorter response time for hydrogen absorption/desorption than dense Pd films, showing promise for hydrogen …

Self-Organized Nanolayers Of Organosilane Molecules, Ocelio V. Lima

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

There is a high degree of interest in organic thin films for lightweight, low power, rugged and flexible electronics. Conjugated organic molecules with polycyclic rings are being considered a major enabler of such applications. Due to a surface tension mismatch between the organic molecule with the inorganic support (mainly silicon oxides), molecular packing inside these thin films is often disordered, which suppresses the device performance. There are major efforts focused on modifying the bulk properties, for instance, maximizing orbital overlaps in the solid state, little attention was paid to receive long-range ordered thin films. A novel approach to afford conjugated …

Production Of Iron Using Environmentally-Benign Renewable Or Recycled Reducing Agents, Timothy C. Eisele, Surendra Komar Kawatra

Michigan Tech Patents

To produce metallic iron from iron ore, a composition comprising a mass of material formed from a mixture of iron ore particles and particles of a reductant that is either a biomass material in particulate form or a plastic resinous material in particulate form is used. The reductant can also be a mixture of biomass material and resin in any proportions. The mass of material comprises at least one body having a shape adapted for smelting such as pellets, briquettes, pieces or lumps. The pellets have sufficient cohesion to maintain the shape into which they have been formed. The invention …

Optical Properties Of Semiconducting Boron Carbide For Neutron Detection Applications, Ravi B. Billa

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Solid state neutron detection devices based on semiconducting boron carbide have the potential for nearly ideal neutron detection effciency for thermal neutrons. The present work is focused on characterizing optical properties of this semiconducting boron carbide material as a step in further development of the material for neutron detection and other applications.

Semiconducting boron carbide films were grown on silicon substrates using plasma enhanced chemical vapor deposition and their optical properties were characterized using variable angle spectroscopic ellipsometry over a wide spectral range, from mid-infrared to vacuum-ultraviolet wavelengths. The effects of deposition substrate temperature and of post-deposition heat treatments on …

Effects Of Overload And Underload On Internal Strains/Stresses And Crack Closure During Fatigue-Crack Propagation, Soo Yeol Lee

Doctoral Dissertations

The overload and/or underload occurring during constant-amplitude fatiguecrack growth result in the retardation and/or acceleration in the crack-growth rate, making it difficult to predict the crack-propagation behavior and fatigue lifetime. Although there have been numerous investigations to account for these transient crackgrowth behavior, the phenomena are still not completely understood.

Neutron and X-ray diffraction, and electric-potential measurements were employed to investigate these transient crack-growth micromechanisms; gain a thorough understanding of the crack-tip deformation and fracture behaviors under applied loads; and establish a quantitative relationship between the crack-tip-driving force and crack-growth behavior. Five different fatigue-crack-growth experiments (i.e., fatigued, tensile overloaded, compressive …

Fundamental Mechanical-Behavior Studies Of Annealed And Nano-Particle-Strengthened Nickel-Based Alloys Using In-Situ Neutron-Diffraction Experiments, E-Wen Huang

Doctoral Dissertations

This dissertation addresses two issues concerning the fundamental mechanical behavior of the nickel-based superalloys: (1) the deformation mechanisms and (2) the nano-precipitate-strengthening effect. The precipitates are known to fortify the mechanical behavior of the metallic alloys. These precipitates can interact with the matrix upon the applied load. While the precipitation strengthening has been facilitated for many purposes, this research puts forward the mechanistic understanding.

The dissertation considers the thesis that Deformation Mechanisms and Nanoprecipitate Strengthening and their effects on the microstructure are central to the mechanical behavior of nickel-based superalloys.

The experimental methods employed in this research are in-situ neutrondiffraction …

Localized Deformation In Metallic Glasses At The Ambient Temperature, Shuangxi Song

Doctoral Dissertations

Metallic glasses have many unusual properties, such as extremely high strength and large elastic limit. However, they are also brittle, failing in a catastrophic manner, as a result of the formation of highly localized shear bands at room temperature. Such flow localization has been attributed to the influence of strain softening or local heating, or a combination of both, which leads to the local drop in viscosity and, finally, the runaway of the shear band.

In this thesis, a novel method was developed for in situ observation of the localized shear processes. The inhomogeneous deformation of metallic glasses at room …

Mechanical Behavior And The Role Of Deformation Twinning In Wrought Magnesium Alloys Investigated Using Neutron And Synchrotron X-Ray Diffraction, Liang Wu

Doctoral Dissertations

The mechanical behaviors and the associated deformation mechanisms with a focus on extension twinning under monotonic and cyclic loadings are investigated using neutron and synchrotron diffractions in the wrought magnesium alloys, ZK60A and AZ31B. It has been demonstrated that the extension twinning plays significant roles in the mechanical behaviors.

The significant tension-compression asymmetries and high anisotropies are observed. The tension-compression asymmetries are related to the twinning activation in one direction but not in the opposite direction. The high anisotropies are correlated with the initial texture distinction relative to the loading directions. The similar yielding stresses are noted irrespective of the …

Thermocapillary Effects In Driven Dewetting And Self-Assembly Of Pulsed Laser-Irradiated Metallic Films, Mikhail Khenner

Mathematics Faculty Publications

A mathematical model for the evolution of pulsed laser-irradiated, molten metallic films has been developed using the lubrication theory. The heat transfer problem that incorporates the absorbed heat from a single laser beam or the interfering laser beams is solved analytically. Using this temperature field, we derive the 3D long-wave evolution PDE for the film height. To get insights into dynamics of dewetting, we study the 2D version of the evolution equation by means of a linear stability analysis and by numerical simulations. The stabilizing and destabilizing effects of various system parameters, such as the reflectivity, the peak laser beam …

Thermocapillary Effects In Driven Dewetting And Self-Assembly Of Pulsed Laser-Irradiated Metallic Films, Mikhail Khenner

Mathematics Faculty Publications

A mathematical model for the evolution of pulsed laser-irradiated, molten metallic films has been developed using the lubrication theory. The heat transfer problem that incorporates the absorbed heat from a single laser beam or the interfering laser beams is solved analytically. Using this temperature field, we derive the 3D long-wave evolution PDE for the film height. To get insights into dynamics of dewetting, we study the 2D version of the evolution equation by means of a linear stability analysis and by numerical simulations. The stabilizing and destabilizing effects of various system parameters, such as the reflectivity, the peak laser beam …

Thermocapillary Effects In Driven Dewetting And Self-Assembly Of Pulsed Laser-Irradiated Metallic Films, Mikhail Khenner

Mathematics Faculty Publications

A mathematical model for the evolution of pulsed laser-irradiated, molten metallic films has been developed using the lubrication theory. The heat transfer problem that incorporates the absorbed heat from a single laser beam or the interfering laser beams is solved analytically. Using this temperature field, we derive the 3D long-wave evolution PDE for the film height. To get insights into dynamics of dewetting, we study the 2D version of the evolution equation by means of a linear stability analysis and by numerical simulations. The stabilizing and destabilizing effects of various system parameters, such as the reflectivity, the peak laser beam …

Hydrometallurgical Process For Extraction Of Metals From Electronic Waste-Part I: Material Characterization And Process Option Selection, Zeljko J. Kamberovic

Zeljko J Kamberovic

Used electronic equipment became one of the fastest growing waste streams in the world. In the past two decades recycling of printed circuit boards (PCBs) has been based on pyrometallurgy, higly polluting recycling technology whic causes a variety of environmental problems. The most of the contemporary research activities on recovery of base and precious metals from waste PCBs are focused on hydrometallurgical techniques as more exact, predictable and easily controlled. In this paper mechanically pretrated PCBs are leached with nitric acid. Pouring density, percentage of magnetic fraction, particle size distribution, metal content and leachability are determined using optical microscopy, atomic …

Thermocapillary Effects In Driven Dewetting And Self-Assembly Of Pulsed Laser-Irradiated Metallic Films, Mikhail Khenner

Mikhail Khenner

A mathematical model for the evolution of pulsed laser-irradiated, molten metallic films has been developed using the lubrication theory. The heat transfer problem that incorporates the absorbed heat from a single laser beam or the interfering laser beams is solved analytically. Using this temperature field, we derive the 3D long-wave evolution PDE for the film height. To get insights into dynamics of dewetting, we study the 2D version of the evolution equation by means of a linear stability analysis and by numerical simulations. The stabilizing and destabilizing effects of various system parameters, such as the reflectivity, the peak laser beam …

Influence Of Grain Boundary Character On Creep Void Formation In Alloy 617, Thomas Lillo, James Cole, Megan Frary, Scott Schlegel

Materials Science and Engineering Faculty Publications and Presentations

Alloy 617, a high temperature creep-resistant, nickel-based alloy, is being considered for the primary heat exchanger for the Next Generation Nuclear Plant (NGNP) which will operate at temperatures exceeding 760^oC. Orientation imaging microscopy (OIM) is used to characterize the grain boundaries in the vicinity of creep voids that develop during high temperature creep tests (800-1000^oC at creep stresses ranging from 20-85 MPa) terminated at creep strains ranging from 5-40%. Observations using optical microscopy indicate creep rate does not significantly influence the creep void fraction at a given creep strain. Preliminary analysis of the OIM data indicates …

Nucleation And Growth Behavior Of Tellurite-Based Glasses Suitable For Mid-Infrared Applications, Jonathan Massera

All Dissertations

Optical fibers transmitting in the 2-5 μm mid-infrared (MIR) spectral region are highly desirable for a variety of military and civilian applications including super-continuum generation, infrared countermeasures (IRCM), and MIR laser sources. These new applications in the mid-infrared require novel optical materials that transmit in this window and can be fabricated into fiber. As tellurite glasses are known to have good transparency in the (NIR) region, tellurite-based glasses are the material of choice for this study due to their high linear and nonlinear refractive index, their low glass transition temperature and the ability to form them into optical fiber.
This …

Modeling Of Metal-Ferroelectric-Insulator-Semiconductor Structures Based On Langmuir–Blodgett Copolymer Films, Timothy J. Reece, Stephen Ducharme

Stephen Ducharme Publications

Among the ferroelectric thin films used in field-effect transistor devices; the ferroelectric copolymer of polyvinylidene fluoride PVDF –CH2–CF2–, with trifluoroethylene TrFE –CHF–CF2–, has distinct advantages, including low dielectric constant, low processing temperature, low cost, and compatibility with organic semiconductors. The operation of a metal-ferroelectric insulatorsemiconductor structure with PVDF-TrFE as the ferroelectric layer was analyzed and optimized by numerical solution of the Miller and McWhorter model. A model device consisting of 20 nm PVDF/TrFE on a 10-nm-thick high-k dielectric buffer exhibits a memory window of 5 V with an operating voltage of 15 V. The operating voltage can be reduced to …

Mechanical And Chemical Characterization Of Biological Composite Structures, Bonnie Zimmerman

All Theses

A better understanding of the bioresponse of naturally occurring systems will help
to optimize the engineering of synthetic biomaterials. The aim of this thesis was to
characterize the mechanical and chemical behavior of two distinct biological composite
systems, human teeth and wool fibers. These mechanical and chemical properties were
also studied as a function of natural structure and environmental conditions.
Human teeth are composite systems consisting primarily of hydroxylapatite and
protein. This project investigated how the use of clinical dental treatments and
procedures, such as whitening and etching, affects mechanical properties. Analysis of
nanoindentation with the Oliver-Pharr model provided elastic …

Precipitate Redistribution During Creep Of Alloy 617, Scott Schlegel, Sharla Hopkins, E. Young, James Cole, Thomas Lillo, Megan Frary

Materials Science and Engineering Faculty Publications and Presentations

Nickel-based superalloys are being considered for applications within advanced nuclear power generation systems due to their high temperature strength and corrosion resistance. Alloy 617, a candidate for use in heat exchangers, derives its strength from both solid solution strengthening and the precipitation of carbide particles. However, during creep, carbides that are supposed to retard grain boundary motion are found to dissolve and re-precipitate on boundaries in tension. To quantify the redistribution, we have used electron backscatter diffraction and energy dispersive spectroscopy to analyze the microstructure of 617 after creep testing at 900 and 1000°C. The data were analyzed with respect …

Simpler Packaging, Tomiko Oden

Graphic Communication

This project explains how product packaging is become more "green", and thus more simple. Packaging needs to go beyond just simplifying materials and graphics - it needs to create a simpler process in order to reduce wasted time, energy, and resources.

Investigation Of The Thermoelectric Behavior And Structure Formation Of (Pbte/Agsbte2)-Silver Chalcogenide Mixtures, Yisha Wang

All Theses

Sustainable energy research is currently on the forefront of scientific exploration and energy conservation and the development of new energy production techniques are both crucial for our long lasting stable future. Accordingly, thermoelectric materials will be a significant energy conservation and production source. The state-of -the-art thermoelectric materials can be used to collect the wasted heat and converted to power, which is the future for the green power generation.
PbTe is considered a state-of-the-art thermoelectric material, which has been extensively studied. It forms in the NaCl structure and it is a semiconductor with a room temperature gap value of 0.29 …

Production And Characterization Of Novel Shaped Fibers For Fluid Sorption And Transport, Lisa Fuller

All Dissertations

This work investigated the production and characterization of novel shaped fibers for fluid adsorption and transport. Shaped fibers such as Y, H, and octolobal, as well as conventional round fibers, were extruded using a research melt extruder. The fibers were extruded from 18 melt flow index (MFI) polypropylene (PP) and blends of 18 MFI PP and 400 MFI PP. Hydrophilic spin finish Bozzetto Favorol SF2 was applied to the surface of extruded fibers and hydrophilic polyester additive LB-100 was included in the blend of some H fibers to increase the hydrophilicity of the fiber surface. The geometric shape retention of …

A Simple Method For Production Of Humidity Indicating Silica Gel From Rice Husk Ash, J Nayak, J Bera

Journal of Metals, Materials and Minerals

The objective of the present work is to develop a procedure for obtaining and characterizing active blue silica from rice husk ash. About 25 wt.% silica powder (from total mass of rice husk) of 95% pure silica could be produced after heat-treating at 700°C for 6 hours. A simple method based on alkaline extraction followed by acid precipitation was developed to produce pure silica hydrogel from RHA. A well-defined very minimum amount CoCl2-containing blue silica gel was prepared by impregnation of the aqueous solution of the salt to silica hydrogel, ageing and drying method. The sharp colour changing from blue …

Synthesis And Characterization Of Sio2 Nanowires Prepared From Rice Husk Ash, S Pukird, P Chamninok, S Samran, P Kasian, K Noipa, L Chow

Journal of Metals, Materials and Minerals

SiO2 nanowires were synthesized by thermal evaporation of rice husk ash and coconut shell charcoal with the ratio of 1:2 by weight heated at a temperature of 1,350ο C in atmosphere of nitrogen for 1 hour. The scanning electron microscope and X-rays diffraction instrument are used to characterize the SiO2 nanowires. The SiO2 nanowires synthesized have diameters varying from 40 nm to 200 nm while the lengths were a few micrometers.

Pozzolanic Activity Of Rice Husk Ash: Comparison Of Various Electrical Methods, S Wansom, S Janjaturaphan, S Sinthupinyo

Journal of Metals, Materials and Minerals

The great abundance of rice husk ash (RHA) as low-cost agricultural waste in Thailand makes it the most suitable material for cement-based applications. However, the use of RHA as a supplementary cementitious material (SCM) is not yet widespread in Thailand due to the poor pozzolanic activity of most agricultural RHA. Most RHA is incinerated at too high temperatures (usually in excess of 1000ºC) or under uncontrolled conditions as biomass fuel. This reduces the amount of amorphous SiO2 and hence worsens the pozzolanic activity of the resulting RHA. To enhance the use of RHA as an SCM in Thailand, a proper …

Exergetic And Thermoeconomic Analyses Of The Rice-Husk Power Plant In Thailand, P Peerapong, B Limmeechokchai

Journal of Metals, Materials and Minerals

The purpose of this study is to analyze a rice husk power plant, and consider the efficiency of the power plant through both the first law and the second law of thermodynamics. The energetic and exergetic performance criteria such as thermal efficiency, exergy efficiency, and exergy loss have been found to be useful methods in design, evaluation, optimization and improvement of thermal power plants. The exergetic efficiency of a power plant shows that the boiler is the major component contributing to total loss, with its exergetic efficiency of 30%, while the steam turbine has the exergetic efficiency of 76%. The …

Synthesis And Characterization Of Silicon-Silicon Carbide Composites From Rice Husk Ash Via Self-Propagating High Temperature Synthesis, S Niyomwas

Journal of Metals, Materials and Minerals

Silicon-Silicon Carbide (Si-SiC) composites were synthesized by self-propagating high temperature synthesis (SHS) from a powder mixture of rice husk ash (RHA)-C-Mg. The reaction was carried out in a SHS reactor under static argon gas at a pressure of 0.5 MPa. The standard Gibbs energy minimization method was used to calculate the equilibrium composition of the reacting species. The comparison of silica from RHA and commercial sources in the precursor mixture on the Si-SiC conversion has investigated using X-ray diffraction and scanning electron microscope technique. The as-synthesized products of Si-SiC-MgO powders were leached with 0.1M HCl acid solution to obtain the …

Ziegler-Natta Catalyst With High Activity And Good Hydrogen Response, L Sinthusai, W Trakarnpruk, R Strauss

Journal of Metals, Materials and Minerals

Ziegler-Natta catalysts were prepared from chemical reaction route comprising of steps of 1) magnesium complex formation between butyloctyl magnesium and 2-ethyl-1-hexanol, 2) MgCl2 support preparation from the reaction between the magnesium complex and TiCl4 as chlorinating agent and 3) titanation with TiCl4. The catalysts were used for ethylene polymerization using triethylaluminum as a cocatalyst. Effects influencing properties of catalysts and polymerization performance were investigated: triethylaluminum/Mg molar ratio, Ti/Mg molar ratio, addition of electron donor and aging step. Results show that addition of ethylbenzoate as an electron donor resulted in decreased catalytic activity. However it was found that catalytic stability under …

Utilization Of Rice Husk To Synthesize High-Performance Phosphors, L Xiong, K Saito, S Wada, E H. Sekiya

Journal of Metals, Materials and Minerals

Rice husk (RH) has high C and Si contents, so it can be used not only as a fuel candidate, but also as a low-cost Si source for synthesizing high-performance products. In the present work, we proposed a low-cost route to synthesize high-performance silicate phosphors with RH. RH was burned either as received or as pretreated by HCl washing. The resulting ashes were, respectively, utilized to react with other raw materials at high temperatures to form silicate phosphors. The high-temperature solid-state reaction process was optimized by varying either the temperature or the holding time. The crystallographic and fluorescent properties of …