+publisher:"University of Florida" +contributor:("VIVIER,VINCENT")

University of Florida

1. Alexander, Christopher L. Impedance Spectroscopy The Influence of Surface Heterogeneity and Application to Corrosion Monitoring of Bridge Tendons.

Degree: PhD, Chemical Engineering, 2017, University of Florida

URL: http://ufdc.ufl.edu/UFE0051021

External post-tensioned tendons are used in bridge construction to link precast concrete segments together. The tendons consist of 7-wire high-strength steel strands contained within a HDPE duct, which is filled with an alkaline grout to protect against corrosion. Despite the use of grout, corrosion has occurred in as little as 7 years compromising the integrity and safety of the bridge. Non-destructive techniques are needed to determine the integrity of the steel without having to break open the tendon. An indirect impedance technique is proposed as a way to detect corrosion within the tendons before failure of the steel occurs. By inserting 4 electrodes into the duct of the tendon to establish electric contact to the grout, the impedance of the grout and the grout and steel interface may be measured. Bench-top experiments were performed on fabricated tendons with and without induced corrosion to show that the indirect impedance was sensitive to the properties of the steel and grout interface. The biggest obstacle in the application of this technique is the lack of a reliable way of interpreting the data. Due to the geometry of the tendon and the configuration of the indirect impedance, frequency dispersion occurs at low frequencies which obscures the actual impedance of the steel. Finite-element models were used to simulate the indirect impedance and determine how the impedance of the grout contributed to the indirect impedance. Advisors/Committee Members: ORAZEM,MARK E (committee chair), ZIEGLER,KIRK JEREMY (committee member), BLOOMQUIST,DAVID G (committee member), VIVIER,VINCENT (committee member).

Subjects/Keywords: corrosion – electrochemistry – impedance

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APA (6^th Edition):

Alexander, C. L. (2017). Impedance Spectroscopy The Influence of Surface Heterogeneity and Application to Corrosion Monitoring of Bridge Tendons. (Doctoral Dissertation). University of Florida. Retrieved from http://ufdc.ufl.edu/UFE0051021

Chicago Manual of Style (16^th Edition):

Alexander, Christopher L. “Impedance Spectroscopy The Influence of Surface Heterogeneity and Application to Corrosion Monitoring of Bridge Tendons.” 2017. Doctoral Dissertation, University of Florida. Accessed January 24, 2020. http://ufdc.ufl.edu/UFE0051021.

MLA Handbook (7^th Edition):

Alexander, Christopher L. “Impedance Spectroscopy The Influence of Surface Heterogeneity and Application to Corrosion Monitoring of Bridge Tendons.” 2017. Web. 24 Jan 2020.

Vancouver:

Alexander CL. Impedance Spectroscopy The Influence of Surface Heterogeneity and Application to Corrosion Monitoring of Bridge Tendons. [Internet] [Doctoral dissertation]. University of Florida; 2017. [cited 2020 Jan 24]. Available from: http://ufdc.ufl.edu/UFE0051021.

Council of Science Editors:

Alexander CL. Impedance Spectroscopy The Influence of Surface Heterogeneity and Application to Corrosion Monitoring of Bridge Tendons. [Doctoral Dissertation]. University of Florida; 2017. Available from: http://ufdc.ufl.edu/UFE0051021

University of Florida

2. Wu, Shao-Ling. Influence of Electrode Geometry on Local and Global Impedance Response.

Degree: PhD, Chemical Engineering, 2010, University of Florida

URL: http://ufdc.ufl.edu/UFE0041985

DISSERTATION TITLE: INFLUENCE OF ELECTRODE GEOMETRY ON LOCAL AND GLOBAL IMPEDANCE RESPONSE ABSTRACT: Distributions of current and potential associated with the electrode geometry are essential issues in studying the electrochemical systems. The nonuniform distributions that cause time-constant dispersion along the electrode surface can obscure results from the electrochemical measurements and lead to an incorrect interpretation of experimental data. The electrode configuration of interest is a disk electrode embedded in an insulator, which is one of the most popular geometries used in the electrochemical measurements. The geometry effect can be observed at high frequencies for a blocking disk electrode and for a disk electrode subject to a single Faradaic reaction. The present study involves more complicated electrode processes that include, first, a coupled Faradaic reactions by an adsorbed intermediate, and then incorporate the nonuniform mass transfer on a rotating disk electrode (RDE) for a general redox reaction. On a stationary disk electrode, while the frequency or time-constant dispersion due to the dependence of the radial distribution of interfacial potential was shown to have an effect at high frequencies, the time-constant dispersion was also found to influence the impedance response at low frequencies due to the potential dependence of the fractional surface coverage of the adsorbed intermediate. The geometry effects were reflected in values for the local Ohmic impedance, which had complex behavior at both high and low frequencies. The dispersion of time constant was described in terms of a local constant-phase element (CPE) that represented the impedance response at low frequencies as well as at high frequencies. The geometry effect can be eliminated by use of a recessed electrode on which the current and potential distributions are uniform. Experimental verification was obtained by applying local electrochemical impedance spectroscopy (LEIS) on an iron disk electrode immersed in a 1 M sulfuric acid solution. The nonuniform mass transfer distribution together with the effect of electrode geometry was investigated on a RDE below the mass-transfer-limited current. A two-dimensional impedance model was proposed to study the influence of nonuniform current and potential distributions associated with both mass-transfer and Ohmic effects on the global and local impedance response. The concentration and potential distributions were calculated simultaneously throughout the system domain by taking into account the transport of species from diffusion, electric migration, and convection. Under the assumption that the Faradaic reaction and the charging of the double layer cannot be separated a priori, part of the flux of reacting species contributes to the charging of the interface as well as to Faradaic reaction. A double-layer model following the Gouy-Chapman type of double layer was used to assess the charge density on electrode without specific adsorption, and to evaluate interfacial properties, such as the… Advisors/Committee Members: Orazem, Mark E. (committee chair), Chauhan, Anuj (committee member), Martin, Charles R. (committee member), Vivier, Vincent (committee member).

Subjects/Keywords: Capacitance; Current density; Electric current; Electrodes; Electrolytes; Geometry; Kinetics; Mass transfer; Rotating disks; Silver; adsorbed, disk, double, electrode, impedance, intermediate, layer

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Wu, S. (2010). Influence of Electrode Geometry on Local and Global Impedance Response. (Doctoral Dissertation). University of Florida. Retrieved from http://ufdc.ufl.edu/UFE0041985

Chicago Manual of Style (16^th Edition):

Wu, Shao-Ling. “Influence of Electrode Geometry on Local and Global Impedance Response.” 2010. Doctoral Dissertation, University of Florida. Accessed January 24, 2020. http://ufdc.ufl.edu/UFE0041985.

MLA Handbook (7^th Edition):

Wu, Shao-Ling. “Influence of Electrode Geometry on Local and Global Impedance Response.” 2010. Web. 24 Jan 2020.

Vancouver:

Wu S. Influence of Electrode Geometry on Local and Global Impedance Response. [Internet] [Doctoral dissertation]. University of Florida; 2010. [cited 2020 Jan 24]. Available from: http://ufdc.ufl.edu/UFE0041985.

Council of Science Editors:

Wu S. Influence of Electrode Geometry on Local and Global Impedance Response. [Doctoral Dissertation]. University of Florida; 2010. Available from: http://ufdc.ufl.edu/UFE0041985

University of Florida

3. Harding, Morgan S. Mathematical Models for Impedance Spectroscopy.

Degree: PhD, Chemical Engineering, 2017, University of Florida

URL: http://ufdc.ufl.edu/UFE0051024

Subjects/Keywords: eis; mathematical-models

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Harding, M. S. (2017). Mathematical Models for Impedance Spectroscopy. (Doctoral Dissertation). University of Florida. Retrieved from http://ufdc.ufl.edu/UFE0051024

Chicago Manual of Style (16^th Edition):

Harding, Morgan S. “Mathematical Models for Impedance Spectroscopy.” 2017. Doctoral Dissertation, University of Florida. Accessed January 24, 2020. http://ufdc.ufl.edu/UFE0051024.

MLA Handbook (7^th Edition):

Harding, Morgan S. “Mathematical Models for Impedance Spectroscopy.” 2017. Web. 24 Jan 2020.

Vancouver:

Harding MS. Mathematical Models for Impedance Spectroscopy. [Internet] [Doctoral dissertation]. University of Florida; 2017. [cited 2020 Jan 24]. Available from: http://ufdc.ufl.edu/UFE0051024.

Council of Science Editors:

Harding MS. Mathematical Models for Impedance Spectroscopy. [Doctoral Dissertation]. University of Florida; 2017. Available from: http://ufdc.ufl.edu/UFE0051024

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