Engineering Commons^™

Addressing Public Fear With Facts—Tva Coal Ash Fact Sheets, Melissa Hedgecoth, Lisa Jn Bradley, Rock Vitale, Neil Carriker

World of Coal Ash Proceedings

No abstract provided.

Developing Single Use Deposits Of Coal Derived Fly Ash As A National Resource, Nigel Cooke

World of Coal Ash Proceedings

No abstract provided.

Six Years Of Service, Supply, And Success: Processing Harvested Ccr From Impoundments, William Fedorka, P.E.

World of Coal Ash Proceedings

No abstract provided.

Experimental Characterization And Manufacture Of Polymer Nanocomposite Dielectric Coatings For High-Temperature Superconductor Applications, Jacob Ryan Mahon

Theses and Dissertations

Increased implementation of high-temperature superconducting (HTS) power transmission has the potential to revolutionize the efficiency of electrical grids and help unlock a fully electric transportation infrastructure. Realizing the benefits of HTS systems has been impeded by a lack of available dielectric insulation materials that can 1) withstand the extreme cryogenic operating environment of superconductors and 2) demonstrate low temperature processing that is compatible with existing superconductor manufacturing methods. Solving this problem necessitates a high-performance dielectric material with multifunctional properties specifically suited for operation in HTS systems. A polyamide and silicon dioxide (PA/SiO2) nanocomposite material with exceptional thermal stability has been …

Development Of New, Diverse Triggering Mechanisms Of Shape Memory Polymers For Cell Mechanobiology Studies, Mark Macios

Theses - ALL

Over the past decade, several shape-memory polymer (SMP) substrates capable of changing topography under cell-culture conditions have been developed for the study of cell mechanobiology. Most initial reports of cytocompatible SMP platforms employed thermal triggering under ambient heating conditions, which, especially in hydrated environments, is a slow process that generally takes several minutes to a few hours. Also, biocompatible SMPs initially featured recovery temperatures too high for cells to maintain viability during the thermal trigger. To overcome the limitations of ambient thermal heating triggered shape recovery, the goal of this thesis was to develop new cytocompatible SMPs that can trigger …

Manipulated Electrochemical Surface Reactions Induced By Oscillatory Electric Potentials On Metal Based Electrodes, Thomas Stone Welles

Dissertations - ALL

This research effort investigates the manipulation of surface electrochemical reactions induced by oscillating electric potentials on the surface of metal-based electrodes. Specifically, this research presents experimental data identifying modified electrochemical surface reactions caused by low magnitude electric potential oscillations on multilayered catalytic membranes and on implanted biometallic alloys. The scope of this effort consists of four major components: (1) perform an exhaustive literature review and analysis of the current understanding in applied surface electrochemistry and develop potential theoretical frameworks by which to interpret the experimental results; (2) identify the electrochemical manipulation via electrical oscillation while reacting nitric oxide on a …

Enhancing Optical And Thermal Properties Of Nanofibrous Films Inspired By The White Beetle Scale, Bokyung Park

Nanoscience and Microsystems ETDs

The Cyphochilus white beetle has received significant attention recently for its exceptional visible-light-scattering properties, owing to the beetle scale's anisotropic nano-fibrillar network structure. Inspiration from the remarkable optical properties of these biological species has directed research efforts to fabricating biomimetic nano-fibrillar structures with polymer materials. In this work, electrospun silk fibroin polymer films reproduce the white beetle scale's anisotropic nature to draw on its optical scattering properties and further improve the radiative-cooling capabilities of silk fabrics. An anisotropically restructured silk film with a mean fiber diameter of a few hundred nanometers substantially increases optical scattering strength in the visible spectrum …

Phase-Field Simulations Of The Precipitation Kinetics And Microstructure Development In Nickel-Based Superalloys, Caleb O. Yenusah

Theses and Dissertations

The continual research and development of nickel-based superalloys is driven by the global demand to improve efficiency and reduce emissions in the aerospace and power generation industries. Integrated Computational Material Engineering (ICME) is a valuable tool for reducing the cost, time, and resources necessary for the development and optimization of the mechanical properties of materials. In this work, an ICME approach for understanding the microstructure development and optimizing the mechanical properties in nickel-based superalloys is employed. Most nickel-based superalloys are precipitate strengthened by either the γ’ phase, γ” phase, or both. Therefore, understanding the precipitation kinetics and morphological evolution of …

Challenges And Signal Processing Of High Strain Rate Mechanical Testing, Barae Lamdini

Theses and Dissertations

Dynamic testing provides valuable insight into the behavior of materials undergoing fast deformation. During Split-Hopkinson Pressure Bar testing, stress waves are measured using strain gauges as voltage variations that are usually very small. Therefore, an amplifier is required to amplify the data and analyze it. One of the few available amplifiers designed for this purpose is provided by Vishay Micro-Measurements which limits the user’s options when it comes to research or industry. Among the challenges of implementing the Hopkinson technology in the industry are the size and cost of the amplifier. In this work, we propose a novel design of …

A Modular Synthesis Of Processable And Thermally Stable Semi-Fluorinated Aryl Ether Polymers Via Step-Growth Polymerization Of Fluoroalkenes, Ketki Eknath Shelar

Theses and Dissertations

Tailored fluoropolymers remain the leading choice for a wide variety of advanced high-performance applications, including electronic/optical and energy conversion, owing to their unique blend of complementary high-performance properties. Amorphous semi-fluorinated polymers exhibit improved solubility and melt processability when compared to traditional perfluoropolymers. A leading class of semi-fluorinated aryl ether polymers includes perfluorocyclobutyl (PFCB), perfluorocycloalkenyl (PFCA), and fluoroarylene vinylene ether (FAVE) polymers. Monomers containing aromatic trifluorovinyl ethers (TFVE) are used to synthesize PFCB polymers via radical-mediated [2+2] cyclodimerization. On the other hand, FAVE and PFCA polymers are polymerized via base-mediated nucleophilic addition/elimination of bisphenols with TFVE monomers and decafluorocyclohexene respectively. The …

Finite-Difference-Time-Domain Simulation Of Ultrafast Experiments, Alpha Ma

Macalester Journal of Physics and Astronomy

The Finite-Difference-Time-Domain (FDTD) method is a numerical method that calculates electric fields or magnetic fields by interleaving them in space and time. Using a python package called “MEEP”, I was able to write optical simulations of ultrafast experiments, especially the Terahertz Pump-Probe experiments. The goal of this project was to use FDTD simulation to measure the transmission of an electro-magnetic pulse passing through a thin film of conducting material on a dielectric substrate in order to study the characteristic conductivity of potential solar cell materials.

Copolymer Microphase Separation, Properties, And Applications, Daniel Weller

Dissertations

Copolymers represent a broad, but critically important class of materials. Often having properties superior to either of its constituents, copolymers are used in virtually all industries including automotive, aerospace, coatings, packaging, and cosmetics. Certain copolymers microphase separate to form nanosized domains that improve the physical properties of the copolymer. The polymer community already has a thorough understanding of how phase separation occurs, but the commercialization of phase separating copolymers lags significantly behind academia. Many of the copolymers that exist that have been undercharacterized and underutilized. This dissertation examines two such polymers. The first, a hard polystyrene material with soft nanodomains. …

Receptor-Doped Organic Transistors: Transducing Anion Binding From Mixed Ionic-Electronic Transport, Anthony Benasco

Dissertations

Organic semiconductors based on π-conjugated polymers show remarkable properties such as high tolerance to structural defects, low processing temperature requirements, biocompatibility, ease of fabrication, and tunable properties. Conjugated polymers integrated into device arrays can exhibit collective properties sensitive to minor perturbations in the surrounding media. However, these devices rely on serendipitous sensitivity to the analyte of interest, and strategies for specific detection remain a considerable change. There remains a compelling, global need for technologies to monitor phosphate due to its prevalence in agricultural runoff, leading to fish kills and economic decline for commercial and recreational fisheries. The strong hydration energies …

Monolithically Integrated Microscale Pressure Sensor On An Optical Fiber Tip, Jeremiah C. Williams, Hengky Chandrahalim

AFIT Patents

A passive microscopic Fabry-Pérot Interferometer (FPI) pressure sensor includes an optical fiber and a three-dimensional microscopic optical enclosure. The three-dimensional microscopic optical enclosure includes tubular side walls having lateral pleated corrugations and attached to a cleaved tip of the optical fiber to receive a light signal. An optically reflecting end wall is distally engaged to the tubular side walls to enclose a trapped quantity of gas that longitudinally positions the optically reflecting end wall in relation to ambient air pressure, changing a distance traveled by a light signal reflected back through the optical fiber.

Biodegradable Active Bio-Nanocomposite Film For The Enhanced Shelf Life Of Tomatoes, Kalpani Y. Perera, Shubham Sharma, Brendan Duffy, Amit K. Jaiswal, Swarna Jaiswal

Articles

The increased environmental pollution has led to finding sustainable solutions for non-renewable plastic-based food packaging materials. Thus, the use of biomaterial-based packaging material has become an immense trend. This work aims at developing an antimicrobial biodegradable chitosan-alginate bio-nano composite film with TiO2 nanoparticle (NPs) for food packaging applications. The film was developed by a solution casting method. The chemical, mechanical, thermal, barrier, antimicrobial, and biodegradable properties of the packaging films were evaluated. Packaging studies were performed for 15 days for cherry tomatoes. The designed packaging material had enhanced the mechanical properties with a significantly (p < 0.05) higher tensile strength of 15.76 folds and 2 fold higher elongation at break. The UV barrier properties increased by 88.6%, while the film transparency decreased by 87.23%. Molecular interaction of N-H covalent bonds was observed between alginate and chitosan together with TiO2 NPs. The developed bio-nano composite film showed antimicrobial activity against foodborne pathogens E. coli, S. aureus, S. typhi, and L. monocytogene with a log reduction of 7.08, 7.28, 6.04 & 6.02 log CFU/ml respectively at 24 hours incubation period. The film was completely biodegraded and a weight loss of 89.06% was observed in bio-nanocomposite film during the 3 months. Shelf-life estimation of cherry tomato using developed packaging films showed an increase in the shelf-life up to 8 days with stable pH, total soluble solids, and weight with no bacterial growth when packaged with prepared film. Owing to their improved mechanical, UV barrier, antibacterial, and biodegradability, the prepared active bio-nano composite packaging films could be considered a potential candidate for fruit packaging.

Relating Detonation Parameters To The Detonation Synthesis Of Silicon Carbide, Martin Langenderfer, Eric W. Bohannan, Jeremy Lee Watts, William Fahrenholtz, Catherine E. Johnson

Chemistry Faculty Research & Creative Works

Detonation synthesis of silicon carbide (SiC) nanoparticles from carbon liberated by negatively oxygen balanced explosives was evaluated in a 23 factorial design to determine the effects of three categorical experimental factors: (1) cyclotrimethylene-trinitramine (RDX)/2,4,6-trinitrotoluene (TNT) ratio, (2) silicon (Si) additive concentration, and (3) Si particle size. These factors were evaluated at low and high levels as they relate to the detonation performance of the explosive and the solid Si-containing phases produced. Detonation velocity and Chapman-Jouguet (C-J) detonation pressure, which were measured using rate stick plate dent tests, were evaluated. Solid detonation product mass, silicon carbide product concentration, and residual silicon …

Analysis Of Hemp Fiber Reinforced Polylactide Composite Under High Strain-Rate, Benjamin Rhoads

Honors Theses

The introduction of hemp fibers into a polylactide (PLA) matrix creates a hemp fiber-reinforced composite with 10% hemp fibers and 90% PLA. Natural fibers are becoming a popular alternative to synthetic fibers since they are environmentally friendly, and hemp-fibers are becoming used more often as the demand for natural fibers increased. A Split-Hopkinson Pressure Bar was used to test this composite against a control group using elastic wave propagation theory. Strain gauges were mounted on the incident and transmission bars of the SHPB to measure the propagation of the wave that caused the strain in the sample, which were used …

Synthesis Of Aromatic Acetylene Alcohols Based On Benzaldehyde And Its Halogenated Products, Sanat Samatov, Abduvakhab Ikramov, Saida Abdurakhmanova, Odiljon Ziyadullayev, Guzal Otamukhamedova

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this study is to synthesize the corresponding aromatic acetylenic alcohols by alkylation with phenylacetylene in a complex catalytic system based on Zn(OTf)₂ and TBAF·3H₂O for the first time with benzaldehyde and some of its halogen derivatives. The selectivity and stability of catalysts used for the yields of reactions for the synthesis of aromatic acetylene alcohols were analyzed. The effect of benzaldehyde and its halogenated derivatives on the product yield was analyzed. The nature, structure, isomerism, spatial structure and other properties influenced to this reactions were studied. Some features of reactions of synthesis of aromatic …

Study Of Sorption Of Some Metal Ions By The Obtained Phosphoric Acid Cation Exchanger Of Polycondensation Type, Malika Berdieva, Rano Nazirova, Alisher Yuldashev, Umida Sharipova, Dilmurod Azimov

CHEMISTRY AND CHEMICAL ENGINEERING

The purpose of this work is to investigate the sorption of Cu²⁺, Co²⁺, Ni²⁺, UO₂²⁺ ions, etc. depending on the ionic form of the cationite and the pH of the medium on phosphoric acid cationite obtained by forsforylation of a polymer based on cubic waste of the Shurtan gas-chemical complex and a secondary product of the hydrolysis industry – furfural. It was found that copper and UO₂²⁺ ions are best sorbed by cationite when the cationite is in Na form. The UO₂²⁺ ion is sorbed fairly well in …

Thermal Properties Of Polyelectrolyte Complexes Of Bombyx Mori Chitosan With Collagen, Shuhrat Khudoyberdiev, Noira Vokhidova, Mukhitdin Abdurazakov, Sayora Rashidova

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the work was to study the thermal behavior of the polyelectrolyte complexes of Bombyx mori ChS with collagen. As a result of the studies, the thermal properties of polyelectrolyte complexes based on Bombyx mori chitosan with collagen in wt. rel. 1:0,1 and 1:0,2 respectively. It has been determined that the most significant weight changes for chitosan with a molecular weight of 15×10³ and the degree of deacetylation of 85% occur at a temperature is 270 °C, when the mass loss rate reaches its maximum value. For collagen, the same temperature is 277 °C. For complexes ChS/collagen …

Glass Micro-Beads For Road Markings On The Basis Of Local Raw Materials, Farrukh Erkinov, Mastura Aripova, Jae-Shin Lee

CHEMISTRY AND CHEMICAL ENGINEERING

One of the priorities for the development of chemical and technological processes in the field of road-building materials and their quality is the production of materials for road markup based on glass micro-beads.

The use of glass micro-beads ensures the required retro-reflection of road marking and indicators of resistance to external influences, compliance with the requirements of regulatory documents. Therefore, the task of developing research approaches to develop a composition and control of road marking, which provide high performance and reduce accidents is an urgent problem.

For this purpose, on the basis of local raw materials, the theoretical foundations of …

Research Of The Process Of Obtaining Crystalline Monocalcium Phosphate Based On Extraction Phosphoric Acid From Phosphorites Of Central Kyzylkums, Kholtura Mirzakulov, Gavkhar Melikulova, Mohichehra Shaymardanova, Sherzod Khujamberdiev

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the research is to establish the optimal parameters of the technological process for the production of feed, crystalline monocalcium phosphate based on defluorinated and desulphated extraction phosphoric acid obtained from phosphorites of the Central Kyzylkum and limestone.

The influence of technological parameters, such as the norms and concentration of phosphoric acid, the process temperature on the filtration rate indicators, the rheological properties of the suspension and the mother liquor, as well as the dependence of the change in the commercial property of crystalline feed monocalcium phosphate, were studied.

It is shown that, regardless of the initial acid …

Investigations Of Roasting Process And Fractional Composition Of Zinc Concentrate Of Khandiza Deposit, Jasur Makhmayorov, Zafar Khakimov, Bakhrom Makhkamov, Murodjon Samadiy

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the study is to study the effect of the process of calcining zinc concentrate from the Khandiza deposit on the degree of zinc extraction and fractional composition. For this, the chemical composition of the concentrate was established and it was shown that the main components are zinc, silicon, potassium, calcium, iron, copper, cadmium, and lead. Titanium, manganese, cobalt, and molybdenum are also contained in small amounts.

Extraction of zinc from a concentrate, calcined at 900 °C for 90 minutes with sulfuric acid with concentration of 18-25% in an autoclave at a temperature of 75 °C, a ratio …

Technology For Producing Alumosilicate Refractory Products Based On Non-Traditional Raw Materials Of Uzbekistan, Ripsime Mkrtchyan

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the study is to develop a technology for producing aluminosilicate refractory products based on non-traditional raw materials - clay shale from the Jerdanak deposit and quartz-pyrophyllite rock from the Boynaksai deposit. The characteristics of prototypes of refractory materials were studied at different ratios of chamotte and binder. Quartz-pyrophyllite rock in its natural state and clay shale after firing at a relatively low temperature (1000 °C) were used as fireclay. The phase composition of the obtained materials was studied by X-ray diffraction and their fine structure by electron microscopy. Technological schemes for obtaining refractory products based on clay …

The Living Breakwaters Pdr Efforts: Conceptual Scheduling, Calvin O. Walters Jr.

Publications and Research

On October 29, 2012, Superstorm Sandy caused nearly $19 billion in damages in New York City including 69,000 residential units across the five boroughs. This disaster precipitated a post-disaster-rebuilding (PDR) project including roughly $4.2 billion in a Community Development Block Grant allocated towards PDR projects. A portion of the grant was used to construct a living breakwater in Tottenville, Staten Island, consisting of a resiliency approach to risk reduction through erosion prevention, wave energy attenuation, and enhancement of ecosystems and social resiliency to improve resistance to storms for the community of Tottenville. The ridges of each breakwater are designed with …

Designing & Building A Microwave Plasma Reactor For Graphene Synthesis, Aviv Zohman, Jerry Larue

Student Scholar Symposium Abstracts and Posters

Graphene’s remarkable electrical, optical, and chemical properties make it a promising successor to indium tin oxide for applications in flexible, transparent electronics. However, efforts to manufacture graphene have been hindered by inefficient synthesis and transfer methods. Chemical vapor deposition (CVD) is commonly used to produce graphene. CVD starts with a blank surface onto which a chemical vapor is deposited to create a single graphene layer. CVD requires extreme temperatures, so only substrates with high melting points are applicable, like metals. This excludes insulative substrates such as polymers which are essential to transparent and flexible devices. Therefore, a subsequent process transfers …

Electromechanical Fatigue Properties Of Dielectric Elastomer Stretch Sensors Under Orthopaedic Loading Conditions, Andrea Karen Persons

Theses and Dissertations

Fatigue testing of stretch sensors often focuses on high amplitude, low-cycle fatigue (LCF) behavior; however, when used for orthopaedic, athletic, or ergonomic assessments, stretch sensors are subjected to low amplitude, high-cycle fatigue (HCF) conditions. As an added layer of complexity, the fatigue testing of stretch sensors is not only focused on the life of the material comprising the sensor, but also on the reliability of the signal produced during the extension and relaxation of the sensor. Research into the development of a smart sock that can be used to measure the range of motion (ROM) of the ankle joint during …

Hinged Temperature-Immune Self-Referencing Fabry–Pérot Cavity Sensors, Jeremiah C. Williams, Hengky Chandrahalim

AFIT Patents

A passive microscopic Fabry-Pérot Interferometer (FPI) sensor includes a three-dimensional microscopic optical structure formed on a cleaved tip of the optical fighter using a two-photon polymerization process on a photosensitive polymer by a three-dimensional micromachining device. The three-dimensional microscopic optical structure having a hinged optical layer pivotally connected to a distal portion of a suspended structure. A reflective layer is deposited on a mirror surface of the hinged optical layer while in an open position. The hinged optical layer is subsequently positioned in the closed position to align the mirror surface to at least partially reflect a light signal back …

Characterization Of Hydrogen Embrittlement Sensitivity In High Hardness Steels, David Ahlen Salley

Theses and Dissertations

High hardness steels can be affected by delayed brittle cracking often attributed to hydrogen embrittlement. Improved resistance to hydrogen embrittlement would be beneficial to many industries including military, automotive, and high-rise construction. While other prevention methods include coating, trapping, and barriers, design efforts in this study were focused on improving intrinsic properties to be more resistant to hydrogen embrittlement. Four alloys targeting 477 – 534 HB were designed and produced in-house and compared against a commercial grade 500 HB alloy. Charpy V-notch (CVN) impact toughness and tensile specimens were made according to ASTM E23 and ASTM E8 to characterize mechanical …

A Study On Effect Of Manufacturing Parameters On Morphology Of A356 Aluminum Foam, Nikhil Nanabhau Mahajan

All Theses

Metal foams have shown an excellent promise for usage as multifunctional material concerning research & development in the last 20 years. They provide remarkable mechanical as well as physical properties being lightweight. Open-cell metal foams have already been used in sound and noise absorption. Open-cell metal foams are outstanding for use in heat exchangers, filters, and many more applications, while closed-cell foams show excellent characteristics in impact energy absorptions. Closed-cell metal foams have higher energy absorption than their solid parent metal as they convert most of the impact energy into deformation energy. Metal foams have been used as prominent safeguard …