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Full-Text Articles in Engineering
Effects Of Carbon-Infiltrated Carbon Nanotube Growth On The Biocompatibility Of 316l Stainless Steel, Sterling Charles Voss
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
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 …
Vertical Electrical Impedance Measurements On Concrete Bridge Decks Using A Large-Area Electrode, Jeffrey David Barton
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
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
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 …
Friction Bit Joining Of Dissimilar Combinations Of Advanced High-Strength Steel And Aluminum Alloys, Lile P. Squires
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
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
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
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 …
Corrosion-Related Gas Measurements And Analysis For A Suite Of Coals In Staged Pulverized Coal Combustion, Todd A. Reeder
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 …
Sensitivity Of Half-Cell Potential Measurements To Properties Of Concrete Bridge Decks, Thad Marshall Pinkerton
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
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
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
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 …