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High Temperature Oxidation Kinetics Of Dysprosium Particles, Brian J. Jaques, Darryl P. Butt 2015 Boise State University

High Temperature Oxidation Kinetics Of Dysprosium Particles, Brian J. Jaques, Darryl P. Butt

Materials Science and Engineering Faculty Publications and Presentations

Rare earth elements have been recognized as critical materials for the advancement of many strategic and green technologies. Recently, the United States Department of Energy has invested many millions of dollars to enhance, protect, and forecast their production and management. The work presented here attempts to clarify the limited and contradictory literature on the oxidation behavior of the rare earth metal, dysprosium. Dysprosium particles were isothermally oxidized from 500 to 1000 °C in N2–(2%, 20%, and 50%) O2 and Ar–20% O2 using simultaneous thermal analysis techniques. Two distinct oxidation regions were identified at each isothermal ...


Under Sleeper Pads: Field Investigation Of Their Role In Detrimental Impact Mitigation, Sakdirat Kaewunruen, Alex M. Remennikov 2015 University of Birmingham

Under Sleeper Pads: Field Investigation Of Their Role In Detrimental Impact Mitigation, Sakdirat Kaewunruen, Alex M. Remennikov

Sakdirat Kaewunruen

Under sleeper pads (USPs) are the component installed under the concrete sleepers generally to improve railway track resilience. Initial development in Europe, particularly in Austria, has encouraged the adoption of the component around the world. In practice, the component has commonly been used in certain applications, mainly to moderate track stiffness in special locations such as turnouts, crossings, and level crossing. In heavy haul operation, the heavier wagons result in sturdier bogie structures, higher unsprung mass, and then higher level of wheel-rail interaction forces. Accordingly, the application of USPs to mitigate detrimental impact load consequence on track structure is presented ...


Consumer Perceptions Towards Package Designs: A Cross Cultural Study, Romica Chandra Lal, Fritz Yambrach, Lucy McProud 2015 San Jose State University

Consumer Perceptions Towards Package Designs: A Cross Cultural Study, Romica Chandra Lal, Fritz Yambrach, Lucy Mcproud

Journal of Applied Packaging Research

The choice of one package or the other can be an economic decision or can be influenced by cultural acceptance or perception of individual convenience. Product package systems can be designed for one-time use or multiple-use purposes. Package perceptions in different countries typically develop from a variety of factors, including climate, lifestyle, and cultural acceptance with regard to particular products. In an increasingly global economy with multinational firms marketing products worldwide, it is important to understand the differences between consumer needs and consumer responses to product-package systems.

The objective of this research was to examine consumer perceptions of different product ...


Capacitance Measurements Of Defects In Solar Cells: Checking The Model Assumptions, Justin R. Davis 2015 Linfield College

Capacitance Measurements Of Defects In Solar Cells: Checking The Model Assumptions, Justin R. Davis

Senior Theses

Capacitance measurements of solar cells are sensitive to minute changes in charge in the material. For that reason, capacitance is used in several methods to electrically characterize defects in the solar cell. Standard interpretations of capacitance rely on many assumptions, which, if wrong can skew the results. We explore possible alternative explanations for capacitance transitions, such as a non-ideal back contact and series resistance. Using Drive Level Capacitance Profiling measurements, a capacitance step is linked to a defect between the energy bands of a solar cell.


Application Of Polyurethane Products In Accelerated Construction Of Innovative Noise Barrier, Bahman Daee 2015 The University of Western Ontario

Application Of Polyurethane Products In Accelerated Construction Of Innovative Noise Barrier, Bahman Daee

University of Western Ontario - Electronic Thesis and Dissertation Repository

Noise barriers (sound walls) are usually constructed along roadways to mitigate the airborne noise emanating from vehicles. They are currently built using various materials including precast concrete panels, masonry, wood and transparent sheets. The main challenge in roadside construction is the obstruction of roadways during the construction, which may result in traffic congestion, public dissatisfaction, car collision and subsequently fatalities. In order to decrease the risk of roadside construction, accelerated and non-obstructive methods are highly preferred by transportation authorities.

An innovative wall system comprised of polyurethane products is proposed, developed and investigated for application in accelerated construction of noise barriers ...


Predictive Modeling Of Oxygen Transmission Through Micro-Perforations For Packaging Applications, Ayman Abdellatief, Bruce A. Welt, Jason Butler, Eric McLamore, Arthur Teixeira, Sanjay Shukla 2015 University of Florida

Predictive Modeling Of Oxygen Transmission Through Micro-Perforations For Packaging Applications, Ayman Abdellatief, Bruce A. Welt, Jason Butler, Eric Mclamore, Arthur Teixeira, Sanjay Shukla

Journal of Applied Packaging Research

Methods for creating precise perforations in respiring produce packaging are being increasingly adopted. Knowledge of oxygen transfer through perforated packaging and oxygen distribution in packages is necessary for successful packaging design of fresh produce. An approach to modeling perforated packaging performance was developed using a cylindrical chamber with precision perforations using Fick’s second law. The model was simulated using two techniques including Finite Element Method (FEM) using commercially available software and Finite Volume Method (FVM) through programming. Perforations were approximated as a source term in the second method. Both simulation techniques showed trends similar to experimental data.


Exploring The Chemistry Of Phosphorus For Photopolymer Applications, Ryan Guterman 2015 The University of Western Ontario

Exploring The Chemistry Of Phosphorus For Photopolymer Applications, Ryan Guterman

University of Western Ontario - Electronic Thesis and Dissertation Repository

Prior to this thesis, phosphorus-containing polymers and photopolymerization represented two distinct, non-overlapping fields of study. This thesis examined the prospect of combining these two approaches to create a system possessing the benefits of both techniques. By exploiting the chemistry of phosphorus, and using photopolymerization as a fabrication method, new materials were developed and assessed for their use in various applications.

Among the many phosphorus compounds that may be used in polymer science, phosphonium salts and primary phosphines were of specific focus. First, highly fluorinated phosphonium monomers were developed to create photopolymerized hydrophobic surfaces. A structure-activity relationship was established, as both ...


Measuring Strain In Trusses, Spencer Metzsch 2015 Linfield College

Measuring Strain In Trusses, Spencer Metzsch

Senior Theses

Strain is an important quantity in engineering design and materials science that relates the deformation of a material to its original length, through a percentage. Different materials exhibit particular qualities under loading, for example the amount of strain due to a certain magnitude of force, or the amount of strain that can be borne before failure. This experiment aims to compare the relative strengths of three common truss configurations by measuring the strain in their members under loading. The Queen’s post truss was found to be the best at minimizing strain under similar loading conditions.


Coexistence Pressure For A Martensitic Transformation From Theory And Experiment: Revisiting The Bcc-Hcp Transition Of Iron Under Pressure, Nikolai A. Zarkevich, Duane D. Johnson 2015 Ames Laboratory

Coexistence Pressure For A Martensitic Transformation From Theory And Experiment: Revisiting The Bcc-Hcp Transition Of Iron Under Pressure, Nikolai A. Zarkevich, Duane D. Johnson

Ames Laboratory Publications

The coexistence pressure of two phases is a well-defined point at fixed temperature. In experiment, however, due to nonhydrostatic stresses and a stress-dependent potential energy barrier, different measurements yield different ranges of pressure with a hysteresis. Accounting for these effects, we propose an inequality for comparison of the theoretical value to a plurality of measured intervals. We revisit decades of pressure experiments on the bcc↔hcp transformations in iron, which are sensitive to nonhydrostatic conditions and sample size. From electronic-structure calculations, we find a bcc↔hcp coexistence pressure of 8.4GPa. We construct the equation of state for competing phases ...


On The Fe Enrichment During Anodic Polarization Of Mg And Its Impact On Hydrogen Evolution, D. Lysne, S. Thomas, M. F. Hurley, N. Birbilis 2015 Boise State University

On The Fe Enrichment During Anodic Polarization Of Mg And Its Impact On Hydrogen Evolution, D. Lysne, S. Thomas, M. F. Hurley, N. Birbilis

Materials Science and Engineering Faculty Publications and Presentations

Iron (Fe) is an unintentional impurity present in pure magnesium (Mg) and Mg alloys, albeit nominally in low and innocuous concentrations (< 100 ppmw). Since Fe, like most metals, is more noble than Mg, the presence of Fe impurities can serve as cathodic sites within the Mg matrix. During anodic polarization of Mg, incongruent dissolution can lead to undissolved Fe impurities accumulating upon the Mg surface, permitting an increase in the overall rate of hydrogen evolution. The experimental manifestation of the incongruent dissolution of Mg, has not yet been clarified, wherein, the extent and efficiency of Fe enrichment during anodic polarization is not known, and also the increase in the hydrogen evolution rate due to Fe enrichment has not been quantified. In this work, Mg specimens with Fe concentration between 40 to 13,000 ppmw were examined in 0.1 M NaCl to obtain a quantitative relation between the Fe concentration and the rate of cathodic hydrogen evolution. These base-line alloys were then anodically polarized to facilitate surface Fe enrichment, and subsequently again cathodically polarized to determine the impact of prior dissolution and Fe enrichment on the subsequent hydrogen evolution. A simple model to predict Fe enrichment was used to analyze the electrochemical data and predict the extent and efficiency of Fe enrichment.


Material Coefficient Of Thermal Expansion Investigation For Use In Additive Manufacturing Fused Deposition Modeling For Composite Tooling, Daniel Miller 2015 The University of Southern Mississippi

Material Coefficient Of Thermal Expansion Investigation For Use In Additive Manufacturing Fused Deposition Modeling For Composite Tooling, Daniel Miller

Master's Theses

Polymer matrix composites are being used to manufacture light weight, high stiffness aircraft structures. These structures are often manufactured from carbon fiber reinforced epoxy. When these structures are damaged, they must be repaired to restore strength to the component to avoid the cost and logistics of having replacements parts. Occasionally, these repairs require tooling in order to make a quality repair, however, tooling generally has a long lead time. Additive manufacturing could be used to manufacture rapid tooling to create tooling for composite repairs. The issue is that polymer printed tooling has a much higher coefficient of thermal expansion (CTE ...


Cure Kinetics, Morphologies, And Mechanical Properties Of Thermoplastic/Mwcnt Modified Multifunctional Glassy Epoxies Prepared Via Continuous Reaction Methods, XIAOLE CHENG 2015 University of Southern Mississippi

Cure Kinetics, Morphologies, And Mechanical Properties Of Thermoplastic/Mwcnt Modified Multifunctional Glassy Epoxies Prepared Via Continuous Reaction Methods, Xiaole Cheng

Dissertations

The primary goal of this dissertation is to develop a novel continuous reactor method to prepare partially cured epoxy prepolymers for aerospace prepreg applications with the aim of replacing traditional batch reactors. Compared to batch reactors, the continuous reactor is capable of solubilizing and dispersing a broad range of additives including thermoplastic tougheners, stabilizers, nanoparticles and curatives and advancing epoxy molecular weights and viscosities while reducing energy consumption.

In order to prove this concept, polyethersulfone (PES) modified 4, 4’-diaminodiphenylsulfone (44DDS)/tetraglycidyl-4, 4’-diaminodiphenylmethane (TGDDM) epoxy prepolymers were firstly prepared using both continuous reactor and batch reactor methods. Kinetic studies ...


Generalized Ellipsometry Analysis Of Anisotropic Nanoporous Media: Polymer-Infiltrated Nanocolumnar And Inverse-Column Polymeric Films, Dan Liang 2015 University of Nebraska–Lincoln

Generalized Ellipsometry Analysis Of Anisotropic Nanoporous Media: Polymer-Infiltrated Nanocolumnar And Inverse-Column Polymeric Films, Dan Liang

Electrical Engineering Theses and Dissertations

Characterization of the structural and optical properties is a subject of significance for nanoporous material research. However, it remains a challenge to find non-destructive methods for investigating the anisotropy of porous thin films with three-dimensional nanostructures. In this thesis, a generalized ellipsometry (GE) analysis approach is employed to study two types of anisotropic nanoporous media: slanted columnar thin films (SCTFs) with polymer infiltration and inverse-SCTF polymeric films. The thesis presents the physical properties obtained from GE analysis, including porosity, columnar shape, principal optical constants, birefringence, etc.

The thesis reports on using a GE analysis approach, combining the homogeneous biaxial layer ...


Characterizing Water As Gap Fill For Double Glazing Units, Bright Adu 2015 Western Kentucky University

Characterizing Water As Gap Fill For Double Glazing Units, Bright Adu

Masters Theses & Specialist Projects

The use of sunlight has always been a major goal in the design and operation of commercial buildings to minimize electrical consumption of artificial lighting systems. Glazing systems designed to allow optimal visible light transmission also allow significant unwanted direct solar heat gain caused by infrared light. Conversely, glazing systems that are designed to reflect unwanted direct solar heat gain significantly reduce the transmittance of visible light through windows. The goal of this research was to characterize the performance of water as gap-fill for double-glazing units in eliminating the compromises that exist in current glazing systems with respect to light ...


Ultrahigh Density Sub-10 Nm Cobalt Nanowire Arrays: Simulation, Fabrication, And Characterization, Yuan Tian 2015 University of Nebraska - Lincoln

Ultrahigh Density Sub-10 Nm Cobalt Nanowire Arrays: Simulation, Fabrication, And Characterization, Yuan Tian

Mechanical (and Materials) Engineering -- Dissertations, Theses, and Student Research

The simulation, fabrication, and characterization of self-assembled ultrahigh density sub-10nm Co nanowire arrays are presented in this dissertation. The general phase separation nanowire growth simulation was operated based on a modified Ising model. The fabrication process can be summarized as the binary Co-X systems lateral phase separation during physical vapor deposition – the plasma layer deposition with a single alloy Co-X target. The “X” stands for Al or Si. The nanowire fabrication and diameter deduction was achieved by balancing the growth rate and surface diffusivity. For Co-Al binary system, the formed sub-10 nm Co nanowires are of face-centered cubic structure through ...


Mitigation Of Aging In Low Voltage Power Cables In Nuclear Power Plants, Robert Jonathan York, Joseph Benjamin Ulrich, Grant Murphy, Daniel George Prather 2015 University of Tennessee - Knoxville

Mitigation Of Aging In Low Voltage Power Cables In Nuclear Power Plants, Robert Jonathan York, Joseph Benjamin Ulrich, Grant Murphy, Daniel George Prather

University of Tennessee Honors Thesis Projects

No abstract provided.


Reaction Kinetics Of Rare Earth And Actinide Materials, Brian Jon Jaques 2015 Boise State University

Reaction Kinetics Of Rare Earth And Actinide Materials, Brian Jon Jaques

Boise State University Theses and Dissertations

This dissertation presents the effects of atmosphere, time, and energy input (thermal and mechanical) on the kinetics of gas-solid and solid-solid reactions in systems of dysprosium, uranium, oxygen, and nitrogen. Accordingly, Chapter Two presents a novel synthesis technique used to form DyN via a gas-solid reaction between dysprosium and nitrogen. DyN was rapidly formed through a mechanochemical process in a high energy ball mill at ambient temperatures. The progress of the reaction was quantified using in situ temperature and pressure measurements coupled with microscopy and x-ray diffraction. It was found that the rate of the nitridation reaction is controlled by ...


Superconductivity Versus Structural Phase Transition In The Closely Related Bi2rh3.5s2 And Bi2rh3s2, Udhara S. Kaluarachchi, Weiwei Xie, Qisheng Lin, Valentin Taufour, Sergey L. Bud'ko, Gordon J. Miller, Paul C. Canfield 2015 Iowa State University

Superconductivity Versus Structural Phase Transition In The Closely Related Bi2rh3.5s2 And Bi2rh3s2, Udhara S. Kaluarachchi, Weiwei Xie, Qisheng Lin, Valentin Taufour, Sergey L. Bud'ko, Gordon J. Miller, Paul C. Canfield

Ames Laboratory Publications

Single crystals of Bi2Rh3S2 and Bi2Rh3.5S2 were synthesized by solution growth, and the crystal structures and thermodynamic and transport properties of both compounds were studied. In the case ofBi2Rh3S2, a structural first-order transition at around 165 K is identified by single-crystal diffraction experiments, with clear signatures visible in resistivity, magnetization, and specific heat data. No superconducting transition for Bi2Rh3S2 was observed down to 0.5 K. In contrast, no structural phase transition at high temperature was observed for Bi2Rh3.5S2; however, bulk superconductivity with a critical temperature, Tc≈1.7 K, was observed. The Sommerfeld coefficient γ and the ...


Molecular Dynamics Simulation Of Irradiation Damage In Multicomponent Alloys, Wei Guo 2015 University of Tennessee - Knoxville

Molecular Dynamics Simulation Of Irradiation Damage In Multicomponent Alloys, Wei Guo

Doctoral Dissertations

The development of the generation IV reactors calls for radiation resistant materials. This thesis proposes that the newly developed single phase solid solution of high-entropy alloys (HEAs) can be such candidates. HEAs can undergo the crystalline to amorphous to crystalline (C-A-C) transitions under radiation. The radiation induced amorphous structure is a highly radiation resistant medium as shown by previous studies, and it further transforms to crystalline phases without much structural defects. In this thesis, by reviewing the formation rules of solid solutions and amorphous metallic glasses, it is suggested that the atomic size plays a key role affecting the C-A-C ...


Improving Mechanical Properties Of Bulk Metallic Glasses By Approaches Of In-Situ Composites And Thin Films, Haoling Jia 2015 University of Tennessee - Knoxville

Improving Mechanical Properties Of Bulk Metallic Glasses By Approaches Of In-Situ Composites And Thin Films, Haoling Jia

Doctoral Dissertations

Bulk-metallic glasses (BMGs) exhibits lots of unique properties, such as, high strengths, high hardness, high specific strengths, superior elastic limits, high corrosion resistance, etc. However, the applications of BMGs are still quite limited due to their intrinsic brittleness and low ductility at room temperature. Many efforts have been conducted to improve the plasticity of BMGs, in which metallic-glass-matrix composites (MGMCs) and thin-film metallic glasses (TFMGs) are two popular and effective approaches. Nevertheless, the deformation mechanisms for the improved plasticity of MGMCs and TFMGs are still far from satisfactory understanding, which will be investigated using both experimental and simulation methods in ...


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