Engineering Commons^™

Effects Of Perforations On Internal Cathodic Protection And Recruitment Of Marine Organisms To Steel Pipes, Alexander John Paluzzi

Theses and Dissertations

Steel monopile support structures for offshore wind turbines require protection from corrosion on their external and internal surfaces. Cathodic protection (CP) works effectively to protect the external surfaces of monopiles, but internally, byproducts from aluminum sacrificial anode CP (SACP) and impressed current CP (ICCP) induce acidification that accelerates steel corrosion. This project investigated the effects of perforations on the performance of aluminum SACP and ICCP when used inside of steel pipes. Additionally, marine growth on the external and internal surfaces of the pipes was assessed to determine if CP byproducts affect marine organism development.

Two sealed and two perforated steel …

Evaluation Of Accelerated Testing Methods To Predict The Effects Of Chemical Exposure On Mechanical Properties Of Polyester Composites In Municipal Wastewater Service, Roberto A. Garcia

Theses and Dissertations

Composite Access Products (CAP) is a company that is determined to replace traditional steel manhole covers with fiber reinforced polymer alternatives that have similar performance while also introducing several advantages. CAP can achieve this by manufacturing the polymer manhole covers using high-speed, high pressure compressing molding to produce lightweight, long-lasting, corrosive resistant covers. CAP’s composite covers have been approved for use by TXDOT in roadway zones. Despite this, they must now undergo more testing and verification for use in environments with highly corrosive elements such as sewage environments and waste processing plants. In these situations, the polymer manhole covers will …

Molten Salt Technologies For Advanced Nuclear Fuel Cycles And Molten Salt Reactors, Dimitris Killinger

Theses and Dissertations

This dissertation provides five topics—an assessment of different monitoring and analytical techniques often cited in the literature for molten salt systems and designs for nuclear engineering applications. First, we explored commonly used materials for quasi-reference electrodes in molten chloride salts. Second, the limitations of the electrochemical analysis known as cyclic voltammetry due to the concentration of uranium(III) present were being investigated. Third, we provided an experimental assessment on the development of a spectroelectrochemical cell for interrogating various spectroelectrochemical techniques, namely chronoabsorptometry and chronofluorometry, and their limitations due to the presence of uranium(III) ions. Fourth, a study on the corrosion resistance …

Effects Of Carbon-Infiltrated Carbon Nanotube Growth On The Biocompatibility Of 316l Stainless Steel, Sterling Charles Voss

Theses and Dissertations

The purpose of this research is to identify the effects of the carbon-infiltrated carbon nanotube (CICNT) growth process on the material properties of 316L stainless steel, particularly those properties which are essential for biocompatibility. Physically altering the micro-topography of a surface can dramatically affect its capacity to support or prevent biofilm growth. Growing CICNTs on biomedical materials is one approach which has demonstrated success at preventing biofilm growth. Unfortunately, the high temperature and carbon-rich gas exposure required for this procedure has proven to have deleterious effects. Rusting has been observed on samples that have been coated with CICNTs and then …

Development Of A Management Guide For Concrete Bridge Decks In Utah, Tenli Waters Emery

Theses and Dissertations

The objectives of this research were to 1) investigate bridge deck condition assessment methods used in the field and laboratory, methods of managing bridge decks, and methods for estimating remaining bridge deck service life using computer models through a comprehensive literature review on these subjects; 2) collect and analyze field data from representative concrete bridge decks in Utah; and 3) develop a decision tree for concrete bridge deck management in Utah. As a result of the literature review performed for objective 1, a synthesis of existing information about condition assessment, bridge deck preservation and rehabilitation, bridge deck reconstruction, and estimating …

The Effect Of Rapid Solidification And Heat Treatment On Microstructure And Electrochemical Properties Of Advanced Biomaterial Co-Cr-Mo-C Alloy, Hamid Reza Erfanian Nazif Toosi

Theses and Dissertations

Co-Cr-Mo-C alloys have been used for implant materials for decades because of their strength, corrosion resistance, wear resistance, and biocompatibility. To develop durable low-friction joint replacement implants, it is important to understand the solidification structure and properties of these materials. While HCP phase is the thermodynamically stable phase in these alloys, they maintain their high-temperature γ-FCC matrix and coarse dendritic structure on cooling to room temperature when cast by conventional methods. In this research, a wedgeshaped copper chill mold was used to examine the effect of cooling rates from 10 K/s to 450 K/s on the microstructure, HCP fraction, and …

Vertical Electrical Impedance Measurements On Concrete Bridge Decks Using A Large-Area Electrode, Jeffrey David Barton

Theses and Dissertations

In regions where chloride-based deicing salts are applied to bridge decks, corrosion of the interior steel reinforcement is a major problem. Vertical electrical impedance (VEI) is an effective measurement technique to quantitatively assess the cover protection on bridges against aggressive chemical penetration of reinforced concrete. In its current form, traditional vertical electrical impedance is time-consuming and destructive because a direct connection to the reinforcing steel is required to provide a ground reference. A new method using a large-area electrode (LAE) permits VEI measurement without a direct electrical connection to the steel reinforcement. The LAE creates a nondestructive, semi-direct, low impedance …

Fundamental Investigation Of Magnesium Corrosion Using Experiments And Simulation, Dila Ram Banjade

Theses and Dissertations

Magnesium (Mg) is the lightest of all structural metals and has tremendous potential for applications in the lightweight industry. However, the corrosion of Mg is a significant barrier towards its wider use. Despite years of research, the fundamental understanding of Mg corrosion still remains short. The enhanced hydrogen evolution reaction (HER) with anodic polarization, the modeling of galvanic corrosion and the impact of hydrogen bubbles for galvanically coupled Mg are important aspects of Mg corrosion that need to be understood before any mitigation measures can be taken. The results presented in this work provide a key step in that direction. …

Toward A Production Ready Fbj Process For Joining Dissimilar Combinations Of Gadp 1180 Steel And Aa 7085-T76, Kevin Alexander Shirley

Theses and Dissertations

Friction Bit Joining (FBJ) is a new technology that can be used to join dissimilar materials together. This ability makes it a good candidate for creating light weight structures for the automotive industry by combining lightweight materials such as aluminum to stronger materials like advanced high-strength steels. The automotive industry and many other industries have great interest in reducing structure weight to increase fuel efficiency. The purpose of this research is to make FBJ of GADP 1180 to AA 7085-T76 a production ready process by (1) better understanding the effects of process parameters, bit design and tool design on joint …

Corrosion Of Aluminum Current Collector In Cost Effective Rechargeable Lithium-Ion Batteries, Shengyi Li

Theses and Dissertations

Rechargeable lithium ion batteries (LIB) have been widely used as commercial energy storage systems for portable equipment, electronic devices and high power applications (e.g. electronic vehicles). One issue with the commercialized LIB is that expensive, highly toxic and flammable organic solvents are used in the electrolyte and the fabrication process of electrodes. The toxic organic based solvents increase the production cost and lead to significant safety concerns in the event of a battery overcharge or short circuit. The recent development of “green manufacturing” technology allows manufacturers to replace the organic solvents used in the cathode coating process by aqueous based …

Microstructure, Wetting Angle And Corrosion Of Aluminum-Silicon Alloys, Shvetashva Suri

Theses and Dissertations

In this study the effect of composition, surface roughness and water droplet size on contact angle and corrosion properties of cast Aluminum-Silicon alloys containing Si from 5% to 50% have been examined. The water contact angle was measured on a given sample using a goniometer. In addition, the effect of surface roughness and droplet size on contact angle has been measured for alloys at a fixed composition. The microstructures can be found in this report with sizes of primary and eutectic Silicon as well as inter-particle spacing between Silicon. Contact angle measurements are accompanied with a photographic validation of the …

Influence Of Permeate From Domestic Reverse Osmosis Filters On Lead Corrosion And Leaching From Plastic Pipes, Jyotsna Shrestha

Theses and Dissertations

Reverse Osmosis filters are gaining popularity nowadays, in domestic water supply system, to meet the increasing demand of pure and improved drinking water. There are various types of domestic RO filters with varying sizes, capacities, and treatment stages available. However, there exist a few concerns regarding the RO treatment system. One of the major issues in the quality and distribution of drinking water is the corrosive water that the RO system produces. Therefore, this research herein tends to focus on the corrosive effect of the permeate water on lead metal, as lead is considered a serious problematic drinking water contaminant. …

Friction Bit Joining Of Dissimilar Combinations Of Advanced High-Strength Steel And Aluminum Alloys, Lile P. Squires

Theses and Dissertations

Friction bit joining (FBJ) is a new method that enables lightweight metal to be joined to advanced high-strength steels. Weight reduction through the use of advanced high-strength materials is necessary in the automotive industry, as well as other markets, where weight savings are increasingly emphasized in pursuit of fuel efficiency. The purpose of this research is twofold: (1) to understand the influence that process parameters such as bit design, material type and machine commands have on the consistency and strength of friction bit joints in dissimilar metal alloys; and (2) to pioneer machine and bit configurations that would aid commercial, …

Sensitivity Of Electrochemical Impedance Spectroscopy Measurements To Concrete Bridge Deck Properties, Hillary Mckenna Argyle

Theses and Dissertations

Numerous methods have been developed to measure corrosion potential relating to chloride infiltration in concrete, including an emerging application of electrochemical impedance spectroscopy (EIS). EIS involves measurements of electrical impedance to evaluate the corrosion potential of steel reinforcement in concrete. With EIS, current is injected vertically into the concrete bridge deck between the surface and the embedded reinforcing steel, usually the top mat, to evaluate the degree to which the reinforcing steel is protected from chloride infiltration by the entire bridge deck system. The objectives of this research were to 1) investigate the sensitivity of EIS measurements obtained at various …

Development Of A Chloride Concentration Sampling Protocol For Concrete Bridge Decks, Sharlan Renae Montgomery

Theses and Dissertations

As the primary cause of concrete bridge deck deterioration in the United States is corrosion of the steel reinforcement as a result of the application of chloride-based deicing salts, chloride concentration testing is among the most common techniques for evaluating the condition of a concrete bridge deck. The objectives of this research were to 1) compare concrete drilling and powder collection techniques to develop a sampling protocol for accurately measuring chloride concentrations and 2) determine the number of chloride concentration test locations necessary for adequately characterizing the chloride concentration of a given bridge deck. Laboratory experiments on concrete drilling and …

Delamination Detection In Concrete Using Disposable Impactors For Excitation, Anjali Narendra Patil

Theses and Dissertations

Delaminations in concrete bridge decks result primarily from corrosion of the reinforcing bars (or rebar). This corrosion leads to volumetric expansion of the rebar. When the rebar expands, concrete cracks, and there is a localized separation of the concrete cover from the underlying concrete. Impact-echo testing is an effective technique to map delaminations on concrete bridge decks. However, mapping speed is limited by necessary retrieval of the impactor for traditional tests. To achieve higher scanning speeds, it is advantageous to use both a non-contact measurement (air-coupled impact-echo) and disposable-impactor excitation. Disposable impactors have the potential advantage of achieving greater deck …

Density Functional Theory (Dft) Study On The Hydrolysis Behavior Of Degradable Mg/Mg Alloys For Biomedical Applications, Marjan Nezafati

Theses and Dissertations

Magnesium-based (Mg and/or Mg alloys) materials possess many advantageous physicochemical/biological characteristics such as good biocompatibility and similarity of the mechanical properties to the human bone tissue, which renders this material a promising candidate for the biomedical and implant applications. One of the most attractive features of Mg-based materials is the degradability in the physiological environment. With the burst of research on the biodegradable materials for the healthcare device applications, Mg and its alloys attracted a strong attention in the bioengineering field in recent years. However, the major limitation of applying Mg-based materials to biomedical applications is the fast degradation/corrosion rate …

System For Detection Of Defects In Cables Of Bridge Structures, Emad Ismail Abdel Salam

Theses and Dissertations

Over the last 75 years, many cable-supported bridges have been built in America, Europe, Asia and other parts of the world. However, over the years these bridges have aged and been exposed to environmental conditions such as rain, snow, de-icing and harmful chemicals. These conditions cause various levels of deterioration in bridges, particularly corrosion. Corrosion causes a loss of cross-section in the steel, adversely affecting the bridge's capacity to carry its service loads, and can possibly cause bridge failures. Although many methods have been attempted to inspect these bridges, most have offered limited success. In the recent years, it has …

Assessing Corrosion Damage In Post -Tensioned Concrete Structures Using Acoustic Emission & A Preliminary Investigation Of Biopolymer Doped Cement Mortar For Use In Structural Restoration, Aditya Appalla

Theses and Dissertations

A sizeable portion of the civil infrastructure is made from concrete. An estimate shows that about 7 billion cubic meters of concrete is made annually worldwide. With the deterioration of the infrastructure due to aging or external factors, significant monetary and technological investment is needed for condition evaluation, maintenance and repair. Two areas that account for a considerable portion of this investment are condition evaluation for maintenance of corroded concrete structures and mortar patching for repair and rehabilitation.

The primary method of evaluation of a structure is by visual inspection. But this method is limited as some crucial areas in …

Assessment Of Damage In Concrete Structures Using Acoustic Emission, Marwa Abdelrahman

Theses and Dissertations

Evaluating the integrity of concrete structures is an essential procedure to ensure structural safety and durability. Non-destructive testing (NDT) is needed for localizing and characterizing the growing damage in existing structures and also for quality control of new structures. Visual inspection is a commonly used method; however it is not suitable for early detection of damage and very dependent on the experience of the inspector. More research is needed to establish advanced methods for structural health diagnosis such as acoustic emission (AE). Acoustic emission is notably sensitive to active damage in concrete structures. This thesis includes three studies that mainly …

The Role Of Zinc Particle Size And Loading In Cathodic Protection Efficiency, Qiang Wang

Theses and Dissertations

Metallic additives, also known as anticorrosive pigments, can provide sacrificial cathodic protection and complement the barrier protection afforded by heterogeneous organic coatings to metallic substrates. The unique systematic study of the corrosion resistance of an epoxy coating reinforced with different sizes (80nm, 500nm, 10um) and continuous multiple pigment volume concentration (0, 2%, 10%, 20%, 45%) below global critical pigment volume concentration of zinc particles were studied. The thesis is developing the fundamental understanding to optimize corrosion protection and predicting the protection with time. The properties of these cathodic coatings were investigated by a single-frequency electrochemical impedance spectroscopy (EIS) and open …

Investigations On The Corrosion Resistance Of Metallic Bipolar Plates (Bpp) In Proton Exchange Membrane Fuel Cells (Pemfc) - Understanding Of The Effects Of Material, Coating And Manufacturing, Ender Dur

Theses and Dissertations

Polymer Electrolyte Membrane Fuel Cell (PEMFC) systems are promising technology for contributing to meet the deficiency of world`s clean and sustainable energy requirements in the near future. Metallic bipolar plate (BPP) as one of the most significant components of PEMFC device accounts for the largest part of the fuel cell`s stack. Corrosion for metallic bipolar plates is a critical issue, which influences the performance and durability of PEMFC. Corrosion causes adverse impacts on the PEMFC`s performance jeopardizing commercialization. This research is aimed at determining the corrosion resistance of metallic BPPs, particularly stainless steels, used in PEMFC from different aspects. Material …

Simulation, Measurement And Image Analysis Of Corrosion Initiation And Growth Rate For Aluminum 2024 And Steel 304, Yan Fang

Theses and Dissertations

Abstract SIMULATION, MEASUREMENT AND IMAGE ANALYSIS OF CORROSION INITIATION AND GROWTH RATE OF ALUMIUM 2024 AND STEEL 304 By Yan Fang, MS A thesis submitted in partial fulfillment of the requirements for the degree of M.S. of Mechanical and Nuclear Engineering at Virginia Commonwealth University. Virginia Commonwealth University, 2011 Major Director: Dr. Brian Hinderliter, Ph. D Associate professor, Mechanical and Nuclear Engineering Time: 11 a.m. Place: Room E3210 Engineering East Hall Date: Friday August 12, 2011 Corrosion initiation and growth rate are important properties in maintaining structural integrity, especially for surface and pit corrosion of common infrastructure and transportation metals. …

Corrosion-Related Gas Measurements And Analysis For A Suite Of Coals In Staged Pulverized Coal Combustion, Todd A. Reeder

Theses and Dissertations

Eleven gas species, including CO, CO2, H2, H2O, H2S, HCl, NOX, O2, SO2, COS and SO3, were measured in a 150 kWth, staged, pulverized coal, down-fired combustor using a Fourier transform infrared (FTIR) spectrometer, gas chromatograph (GC), and a Horiba PG-250 5-gas analyzer. Additional gases such as HCN, NH3, CH4, and other hydrocarbons were also measured. Seven coals of varying rank and composition were investigated. Measurements were obtained in reducing (S.R. = 0.85) and oxidizing (S.R. = 1.15) conditions. In particular, sulfur- and chlorine-containing species including H2S, SO2, COS, SO3, and HCl are discussed. In the reducing zone, all four …

Corrosion Damage Studies Through Microscopy And Stress Analysis, Ronak Patel

Theses and Dissertations

Corrosion is the destructive result of chemical reaction between a metal or metal alloy and its environment. Airplanes, power generating plants, chemical process and manufacturing plants, concrete structure, and many others which widely uses aluminum alloy and stainless steel alloys are subjected to corrosion. The estimated cost of corrosion damage is in order of 3 to 5 percent of gross national product (GNP). Out of all forms of corrosion, pitting corrosion is most commonly observed in aluminum alloy 2024 and stainless steel type 316. There is a need to study the stress environment around the pits in order to predict …

Sensitivity Of Half-Cell Potential Measurements To Properties Of Concrete Bridge Decks, Thad Marshall Pinkerton

Theses and Dissertations

Half-cell potential testing has been recommended as a non-destructive method for assessing the corrosion potential of reinforcing steel in concrete bridge decks. The technique is particularly useful because it can be utilized to evaluate the probability of corrosion before damage is evident at the surface of a bridge deck. The specific objective of this research was to quantify the effects of age, chloride concentration, concrete cover thickness, spatial position, temperature, and presence or condition of epoxy coating on half-cell potential measurements of concrete bridge decks typical of those in Utah. The laboratory testing associated with this research followed a full-factorial …

Effect Of Stay-In-Place Metal Forms On Performance Of Concrete Bridge Decks, Stephen Litster Frost

Theses and Dissertations

The objectives of this research were to investigate the effect of stay-in-place metal forms (SIPMFs) on the performance of concrete bridge decks in Utah. The research program included six bridge decks with SIPMFs and six decks without SIPMFs, which were all located within the Interstate 215 corridor in the vicinity of Salt Lake City, Utah, and therefore subject to similar traffic loading, climatic conditions, and maintenance treatments, including applications of deicing salts during winter months. All of the tested decks were constructed between 1984 and 1989 using epoxy-coated rebar. Several tests were performed at each of six locations on each …

An Analysis Of Microstructure And Corrosion Resistance In Underwater Friction Stir Welded 304l Stainless Steel, Tad Dee Clark

Theses and Dissertations

An effective procedure and parameter window was developed for underwater friction stir welding (UWFSW) 304L stainless steel with a PCBN tool. UWFSW produced statistically significant: increases in yield strengths, decreases in percent elongation. The ultimate tensile strength was found to be significantly higher at certain parameters. Although sigma was identified in the UWFSWs, a significant reduction of sigma was found in UWFSWs compared to ambient FSWs. The degree of sensitization in UWFSWs was evaluated using double loop EPR testing and oxalic acid electro-etched metallography. Results were compared to base metal, ambient FSW, and arc welds. Upper and lower sensitization localization …

Effects Of Friction Stir Processing On The Microstructure And Mechanical Properties Of Fusion Welded 304l Stainless Steel, Colin J. Sterling

Theses and Dissertations

Friction stir processing (FSP) has been utilized to locally process regions of arc weldments in 304L stainless steel to improve the microstructure and mechanical performance. The cast microstructure and coarse delta-ferrite has been replaced with a fine-grained wrought microstructure. Furthermore, twins were introduced throughout the friction stir processed region. Although sub-surface sigma and carbides were introduced during FSP, their presence is not expected to adversely affect the resulting mechanical or corrosion properties of friction stir processed 304L arc welds. The resulting mechanical properties of FS processed weldments were also an improvement over as-welded arc welds. FSP resulted in an increase …