Engineering Commons^™

Structure Analysis Of Pemfc Cathode Catalyst Layer, Rui-Qing Wang, Sheng Sui

Journal of Electrochemistry

The sluggish oxygen reduction reaction (ORR) on the cathode of the proton exchange membrane fuel cell (PEMFC) has always been one of the key factors limiting its commercialization. The optimization of the cathode catalytic layer structure plays an important role in improving fuel cell performance and reducing production costs. In this paper, two different catalysts (platinum nanoparticles (Pt-NPs) and platinum nanowires (Pt-NWs)) were prepared by using catalyst coated substrate (CCS) method. By constructing a double-layer catalytic layer structure, we analyzed the effect of different catalytic layer structures by performing a single cell test. The results showed that the dense platinum …

Study Of The Thermodynamic Properties Absorbation Sulfur Storage Gas Of Zinc And Copper Industry, Berdiyarov Tilovkabulovich Berdiyarov Dr., Sh. T. Khojiev, S. T. Matkarimov, Sh. Munosibov

Technical science and innovation

The article considers the problems of utilization of industrial gases formed in the production of copper and ore containing sulfur anhydrides. Currently, the composition of process gases entering the gas purification department is approximately 6-7% SO₂, 0.2-0.3% SO₃ and other gases, until sulfuric acid is obtained from these gases, the sulfate is treated in a counter-scheme with 8% sulfate acid. The aim is to first reduce the temperature of the exhaust gases and second to avoid flying components such as as As, F, Se. As a result of the studies, the amount of SO₂ in the …

Temperature-Immune Self-Referencing Fabry–Pérot Cavity Sensors, Hengky Chandrahalim, Jonathan W. Smith

AFIT Patents

A passive microscopic Fabry-Pérot Interferometer (FPI) sensor an optical fiber a three-dimensional microscopic optical structure formed on a cleaved tip of an optical fighter that reflects a light signal back through the optical fiber. The reflected light is altered by refractive index changes in the three-dimensional structure that is subject to at least one of: (i) thermal radiation; and (ii) volatile organic compounds.

Effects Of Bonding Pressure And Lamina Thickness On Mechanical Properties Of Clt Composed Of Southern Yellow Pine, Cody S. Bates

Theses and Dissertations

This study produced cross-laminated timber panels at a range of four lamina thickness (5/8, 1, 1 1/8, and 1 1/4 inch) and three bonding pressures (50, 125, 200 psi), producing a total of 12 panels for mechanical testing. The goal of this study is to observe how the thickness and pressure trends affect the mechanical properties of CLT. Tests include flatwise bending, flatwise shear, internal-bond, and delamination. Results showed that bending MOE decreases as the panel thickness increases while bonding pressure had no significance. Bending MOR was less significant for the thickness and more significant for pressure compared to the …

Study Of Alloy And Process Modifications To Design Hydrogen Resilient High Hardness Steels, William R. Williams

Theses and Dissertations

High hardness steels (HHS) are vulnerable to hydrogen embrittlement, which can lead to rapid degradation of mechanical properties. Improved resistance to hydrogen embrittlement would be beneficial to many industries including construction, automotive, and military. A comparison study was performed to assess the hydrogen susceptibility of select commercially available and in-house designed HHS alloys. Slow strain rate tensile tests, performed with specimens charged with various levels of hydrogen, provided a macroscopic view of the onset of hydrogen embrittlement. Hydrogen permeation and thermal desorption spectroscopy tests determined the uptake and diffusivity of hydrogen through the material. The evaluation of hydrogen susceptibility for …

Predictive Computational Materials Modeling With Machine Learning: Creating The Next Generation Of Atomistic Potential Using Neural Networks, Mashroor Shafat Nitol

Theses and Dissertations

Machine learning techniques using artificial neural networks (ANNs) have proven to be effective tools to rapidly mimic first principles calculations. These tools are capable of sub meV/atom accuracy while operating with linear scaling with respect to the system size. Here novel interatomic potentials are constructed based on the rapid artificial neural network (RANN) formalism. This approach generates precise force fields for various metals that have historically been difficult to describe at the atomic scale. These force fields can be utilized in molecular dynamics simulations to provide new physical insights. The RANN formalism, which is incorporated into a LAMMPS molecular dynamics …

Energy Efficient Configuration Or Perforated Solar Screens For Residential Desert Buildings, Rasha Arafa

Archived Theses and Dissertations

In hot arid desert environments, the solar radiation passing through windows increases the cooling loads and energy consumption of buildings. Shading of windows can reduce these loads. External perforated wooden solar screens were traditionally used for windowsâ shading. However, there is a lack in understanding their performance in a quantitative manner and unavailability of scientific means that could be used for developing new efficient designs that suit the harsh desert conditions. This thesis investigates the impact of changing screen configurations such as perforation percentage, depth, perforation openings aspect ratio and reflectivity on the energy loads, hence defining the most efficient …

The Process-Structure-Property-Performance Of Aisi 1020​, Jonathan Wellman, Tate James, Robbie Christman, Brian Broom

ME 4133/6133 Mechanical Metallurgy

AISI 1020 is widely used in many different industries due to its high strength, high ductility, high machinability, and good weldability. AISI 1020 has a number of applications. Low carbon steel can be used on a macroscale to build bridges, and low carbon steel can be used on smaller scales such as Lawnmower blades. Low carbon steel is the material of choice for lawn mower blades because of its ability to bend before it breaks. The ductile attribute of low carbon steel also has many other benefits.

Ti-6al-7nb Utilization In Surgical Implants, Michael O. Fleming

ME 4133/6133 Mechanical Metallurgy

This presentation discusses the processing, structure, properties, and performance of Ti-6Al-7Nb in relation to use as a surgical implant.

The Effect Of Air-Entraining On Concrete Durability, Jane Magdy Aziz Abadir

Archived Theses and Dissertations

No abstract provided.

Finite Element Modeling Of Superplastic Forming Of High Strength Aluminium Alloys (Weldalite Tm 049), Ihab Farouk Nabil Ragai

Archived Theses and Dissertations

No abstract provided.

Elastic-Plastic Behavior And Limit Load Analysis Of Pipe Bends Under Out-Of-Plane Moment Loading And Internal Pressure, Hashem Mo Mourad

Archived Theses and Dissertations

No abstract provided.

Effect Of Mechanical Systems In Combating The Schistosomiasis Snails, Sherine Ahmed El Baradei

Archived Theses and Dissertations

No abstract provided.

Development Of Pspp Map For Stainless Steel Alloys Used In A Marine Environment, Jarrett D. Hawkins

ME 4133/6133 Mechanical Metallurgy

A process-structure-properties-performance map will be created for these alloys focusing on the modification of the structure or composition and outlining the processes required and the affected properties. A thorough review of different chemical alloys, grain refining methods, and grain boundary compositions for several alloys and their corresponding property effects. Also plan to review material treatment processes and standard refining methods for stainless steels. The performance of these metals will be evaluated for property requirements in regards to strength, toughness, with an emphasis on corrosion resistance.

A Temporal Analysis Of The Microbiota And Biofouling Development On Artificial Substrates In The Port Everglades Inlet, Florida, Denise Swack

All HCAS Student Capstones, Theses, and Dissertations

A pilot project was deployed in Port Everglades Inlet, Florida that aimed to evaluate the biofilm composing the microbiome on ecologically engineered artificial substrates used to build Coastal Marine Infrastructure. In April of 2017, an Articulated Concrete Block Mattress comprised of an ecological engineered concrete substrate and a standard smooth surface control substrates were compared. This study will provide a profile on the microbiome community on artificial substrates within Port Everglades Inlet on bio-enhancing concrete-based solutions in our Coastal Marine Infrastructure. To study the microbial community, the 16s rRNA technology was used in Illumina’s high-throughput DNA sequencing. Samples were collected …

Tungsten: The Strongest Natural Metal On Earth, Haley E. Holland, Razan Khadka, Lee Marble, Kaleb Tutor

ME 4133/6133 Mechanical Metallurgy

The overall objective of this project was to construct a process-structure-property-performance (PSPP) map for a chosen metallic material. The material chosen by the group is tungsten (W). Tungsten is a rare, naturally occurring element and is usually found in the form of ores. It is known predominantly for its ability to withstand extreme temperatures, as well as its high tensile strength. The PSPP map displays many specifications of tungsten in each of the four categories and further details regarding each specific linkage, or subcategory, within the map are written throughout the research paper.

Along with the four specific categories outlined …

Analysis Of Titanium Alloy Ti-6al-4v, Hunter C. Smith, Gordin Smith

ME 4133/6133 Mechanical Metallurgy

Titanium alloy Ti-6Al-4V was chosen for examination, more specifically, the Properties and Performance of the alloy. The students will share the responsibility of examining the attributes of the material. The team members participate evenly in performing research, producing calculations, and constructing the final report. Contained herein is the information gathered through research conducted thus far.

The performance of the material will be related to the processing methods of the material. This relationship forms the basis of cost analysis. The students will examine the atomic characteristics and crystalline structure to determine the effects of the alloyed materials on properties such as …

An Analysis Of The Effects Of Process, Structure, And Properties On The Performance Of The Ti6al4v Alloy, Brad Jay Sampson, Loubna Ifqir

ME 4133/6133 Mechanical Metallurgy

Ti6Al4V (pronounced Ti-64), is a titanium alloy used in a variety of engineering applications including the aerospace, automotive, and biomedical industries. Ti6Al4V is made up of a combined ɑ-β microstructure, which provides it with many valuable properties such as high strength, low weight, high melting point, corrosion resistance, and biocompatibility. [1] For years, casting and forging have been the traditional processes used for the manufacturing of Ti6Al4V components, but recent interest in the additive manufacturing of Ti6Al4V through the Electron Beam Melting (EBM), Selective Laser Melting (SLM), and Directed Energy Deposition (DED) methods has been gained. The goal of this …

Al 6061 Alloy, Will Mckelvey, Evan Robertson, Justin Yates

ME 4133/6133 Mechanical Metallurgy

We want to portray the Al 6061 manufacturing and machining processes and how these affect the mechanical properties of the material. We also want to portray the strength and weaknesses and the reasons why it is used in certain applications.

Duplex Stainless Steel 2205 In The Pulp And Paper Industry, Charlie S. Wilcher, Trevor Davus

ME 4133/6133 Mechanical Metallurgy

Duplex stainless steel’s durability, formability, and resistance to corrosion make it the primary steel option of the pulp and paper industry. The harsh environments found in certain aspects of this industry, such as in bleach plants, digesters, liquor vessels, and any piping where corrosive liquids may be passed, require the previously mentioned properties that duplex stainless steel 2205 offer. The structure and properties of duplex stainless steel, as well as the processes it undergoes, allow for it to withstand these environments. Research into the structure and properties of duplex stainless steel and the processes it undergoes will indicate how duplex …

Ar400 Wear Plates, Jase Tatum, Bryson Miller, John Howell, Aaron Alexander

ME 4133/6133 Mechanical Metallurgy

Wear resistance is an invaluable performance metric for most metallic components found in mechanical systems. Our research focused on AR400, a steel alloy known for its wear resistance capabilities, in an effort to determine what factors might be attributed to its performance in wear applications. After establishing the processing techniques and resulting material structures that give AR400 such an edge in extreme wear conditions, our goal is to determine indicators of wear resistance that can be used to distinguish excellent wear resistant alloys from average or subpar performers against wear.

Investigating Cobalt Chrome Alloy For Use In Biomedical Applications, Morgan Calhoun, Caitlin Cade

ME 4133/6133 Mechanical Metallurgy

Cobalt Chrome alloys, in particular cast Co-Cr ASTM-F75, are often used as the material for medical implants due to a combination of material properties: high strength, stiffness, temperature endurance, and wear / corrosion resistance. We aim to demonstrate and discuss what characteristics make it such a desirable material in the production of metallic biomedical implants

Titanium Ti-6al-4v, James Aaras Ross Brundege

ME 4133/6133 Mechanical Metallurgy

Titanium alloys, such as Ti-6A1-4V, used as biomaterials possess great characteristics compared to other alloys such as stainless steel alloys. Characteristics such as biocompatibility, enhanced corrosion, strain, and fatigue resistance provide amazing benefits from these alloys. Providing an understanding of Ti used in biomedical applications and production can provide insight into its benefits and limitations as well as the areas of potential improvement for future study.

3xx Aluminum Alloys For Ice Implementation, Kyle A. Taylor, Eric Cleckner, Jeffery Garrett

ME 4133/6133 Mechanical Metallurgy

The material to be explored for the purpose of this project relates to the Aluminum alloys used in the majority of modern engine “heads” and a number of engine “blocks”. The Aluminum used for these engine applications vary slightly across different manufacturers in their processing, structure and ultimate properties, despite their nearly identical performance applications. Part of the interest in this particular subject is the slight variations across manufacturing that result in different performance. Regardless of idiosyncrasies, these Al alloys are expected to perform under varying temperatures, with the ability to elastically deform and return to their original shape. They …

Rheological Properties Of Recyclable Polymer Matrices For Advanced Composite Applications, Rahul Shankar

Dissertations

This dissertation focuses on evaluating the rheological characteristics of a variety of recyclable polymer matrices, which can compete with thermosets in a wide range of specialized applications. Studying the fundamental solid and melt-state viscoelastic properties and establishing structure-property-processing relationships is critical for the widespread adoption of these novel recyclable polymers in commercial applications. The first chapter provides an introductory overview of the different recyclable polymer matrices and their applications including high performance thermoplastics as thermoset replacements in high energy composite manufacture, multifunctional specialty thermoplastics for additive manufacturing and next generation, reprocessable covalent adaptable networks for self-healing applications. Furthermore, the important …

Shear Strength Of Concrete Beams Made With Belitic Calcium Sulfoaluminate Cement, Caleb W. Chesnut

Graduate Theses and Dissertations

The need for a cleaner alternative to portland cement (PC) concrete has led to increasing interest in alternatives to PC. Structural properties of most of these alternative cements are still an open research topic. One promising alternative cement is belitic calcium sulfoaluminate (BCSA) cement. The study presented in this paper investigated the shear strength, long term compressive strength, and carbonation in BCSA cement and PC concrete beams. A total of twelve eight-foot long beams were made; eight BCSA cement concrete beams and four PC concrete beams to be tested at various ages depending on cement type. Two beams of each …

Synthesis, Characterization And Tribological Properties Of Mo-Dlc, Tirth Ashishbhai Patel

Material Science and Engineering Theses - Archive

Diamond like carbon (DLC) films have been extensively used in a wide range of applications over the last decade due to their excellent mechanical and tribological properties. Metallic elements are used to dope DLC films in an effort to overcome some DLC limitations and make it compatible to use it in larger variety of applications. This study focuses on the effect of different processing parameters on DLC deposition, and the effect of Mo content on microstructure, mechanical and tribological properties. Plasma Enhanced Chemical Vapor Deposition (PECVD) technique coupled with magnetron sputtering is used in chamber atmosphere composed of CH4 and …

The Effects Of Snagcu Solder Interconnect Package’S Parameters On Electromigration Failure Mechanisms, Yi Ram Kim

Material Science and Engineering Dissertations - Archive

The primary concern of this dissertation is the electromigration (EM) failure mechanism found in Sn-Ag-Cu (SAC) solder alloys integrated in WCSP (wafer-level chip scale package) packaging structure and factors affecting the failure mechanisms. To the end, accelerated electromigration (EM) tests are conducted on SnAgCu (SAC) solder interconnects in wafer-level chip scale packages (WCSPs or WLCSPs) with different package structures and use-condition parameters. The package structure parameters include different under bump metallization (UBM) thicknesses, Sn grain orientation, while the various in use conditions includes pulsed direct current (DC), and alternating current (AC). The major findings made in the studies are presented …

Plasma Electrolytic Oxidation Of Pure Titanium At Constant Applied Voltage, Hunter Pitts

Material Science and Engineering Theses - Archive

Plasma Electrolytic Oxidation (PEO) is a method of coating which is used to apply non metal coatings to different metal substrates. This process occurs in an electrochemical cell that consists of an electrolyte, two electrodes submerged in the electrolyte and a power supply supplying voltage to the two electrodes. The goal of this study was to observe how a constant applied voltage would affect the coating thickness at varied applied voltage and varied processing time. This study was a continuation of a constant applied voltage study previously performed in the SaNEL research group. It was continued to add more detailed …

Study Of Sac Solder Interconnect Parameters In Microelectronic Semiconductor Packaging And Their Effects On Electromigration Failure Mechanisms, Allison Theresa Osmanson

Material Science and Engineering Dissertations - Archive

As the shrinkage of electronic devices becomes more appealing, so do their high capacity and efficiency. This demand for ever-shrinking sizes of electronic devices follows the trend predicted by Moore’s Law. To achieve smaller devices, reduced sizes of solder joints, Cu traces, Cu pads, and other components in packages are implemented with tighter tolerances for geometries and layouts. With each incremental change in dimension or material, new reliability challenges emerge. Electromigration (EM), the directional diffusion of atoms with the flow of electrons, has been an inevitable reliability concern for microelectronic device packaging. It is one common failure mechanism in wafer-level …