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Title: The determination of total organic carbon in seawater.
Creator: Peterson, Gary N., Montgomery, John R.
Date Issued: 1981-01
PURL: http://purl.flvc.org/fcla/dt/3358748
Subject Headings: Water--Carbon content--Measurement, Seawater--Organic compound content, Plankton
Format: Document (PDF)

Title: Design of cathodic protection using BEM for components of the piilot ocean energy system.
Creator: Gantiva, Nicolas., College of Engineering and Computer Science, Florida Atlantic University, Department of Ocean and Mechanical Engineering
Abstract/Description: The Center for Ocean Energy Technology at Florida Atlantic University is developing an ocean energy turbine system to investigate the feasibility of harnessing Florida's Gulf Stream current kinetic energy and transforming it into a usable form. The turbine system has components which are prone to marine corrosion given the materials they are made of and to the harsh environment they will be exposed to. This study assumes a two-part system composed of a coating system acting as a barrier and...
Show moreThe Center for Ocean Energy Technology at Florida Atlantic University is developing an ocean energy turbine system to investigate the feasibility of harnessing Florida's Gulf Stream current kinetic energy and transforming it into a usable form. The turbine system has components which are prone to marine corrosion given the materials they are made of and to the harsh environment they will be exposed to. This study assumes a two-part system composed of a coating system acting as a barrier and sacrificial anode cathodic protection which polarizes the metal structures to a potential value where corrosion is significantly reduced. Several configurations (varying in anode quantity, size and location) were considered in order to cathodically protect the structures with various coating qualities (poor, good and excellent). These cases were modeled and simulated via Boundary Element Method software and analyzed so as to assess the most appropriate design.
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Date Issued: 2010
PURL: http://purl.flvc.org/FAU/2684309
Subject Headings: Cathodic protection, Corrosion and anti-corrosives, Finite element method, Seawater corrosion, Prevention
Format: Document (PDF)

Title: Cathodic polarization response of simulated prestressed concrete piles exposed to natural sea water.
Creator: Chaix, Olivier., Florida Atlantic University, Hartt, William H.
Abstract/Description: Experiments were conducted to determine the effectiveness of localized cathodic polarization for reducing corrosion of simulated prestressed concrete piles containing admixed calcium chloride and exposed to a simulated sea water tidal cycle. The specimens contained both continuous and segmented steel tendons, the purpose of the latter being to facilitate measurement of cathodic protection current. Conductive rubber in an impressed current system was used as the anode material. The specimens...
Show moreExperiments were conducted to determine the effectiveness of localized cathodic polarization for reducing corrosion of simulated prestressed concrete piles containing admixed calcium chloride and exposed to a simulated sea water tidal cycle. The specimens contained both continuous and segmented steel tendons, the purpose of the latter being to facilitate measurement of cathodic protection current. Conductive rubber in an impressed current system was used as the anode material. The specimens were initially freely corroded and then cathodically polarized at a constant current ranging from 0.5 to 1 mA/m$\sp2$ which corresponded to potentials (current-on) which ranged from $-$0.500 to $-$1.100 V(sce) in the anode region. The magnitude of impressed current and its distribution along the embedded steel was monitored as a function of exposure time, level of polarization and water levels. Current-on and instant-off potential distribution for both the continuous and segmented tendons were also measured. The level of cathodic polarization was assessed as a function of position along the specimens by the depolarization method. The results were evaluated within the context of marine bridge substructure cathodic protection technology.
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Date Issued: 1992
PURL: http://purl.flvc.org/fcla/dt/14865
Subject Headings: Corrosion and anti-corrosives, Sea-water corrosion, Offshore structures, Reinforced concrete--Deterioration
Format: Document (PDF)

Title: Effect of cathodic protection and cyclic frequency on corrosion fatigue of selected high strength steels in seawater.
Creator: Badve, Ashwin P., Florida Atlantic University, Hartt, William H.
Abstract/Description: Study of selected candidate steels for offshore application was undertaken to observe the effects of cathodic protection and cyclic frequency on corrosion fatigue life. Keyhole Compact Tension Fatigue experiments under constant amplitude sinusoidal loading and stress ratio of 0.5 were performed on 25.4 mm thick specimens in natural sea water and also in air upon three different steels (Y.S. 500-563 MPa). These steels represented different strengthening techniques, namely precipitation...
Show moreStudy of selected candidate steels for offshore application was undertaken to observe the effects of cathodic protection and cyclic frequency on corrosion fatigue life. Keyhole Compact Tension Fatigue experiments under constant amplitude sinusoidal loading and stress ratio of 0.5 were performed on 25.4 mm thick specimens in natural sea water and also in air upon three different steels (Y.S. 500-563 MPa). These steels represented different strengthening techniques, namely precipitation hardening, direct quenching--a thermomechanical control process (TMCP), and controlled rolling. Cathodic polarization was in the range between freely corroding and -1.10 Volts (SCE). The tests were performed at a frequency of 0.3 and 1.0 Hz. The results are presented in the S-N and potential versus cycles to initiation format. No effect of frequency (1.0-0.3 Hz) was observed at cathodic protection of -1.10 V (SCE). The steels showed an increase in fatigue life to an optimum potential, and excessive potentials were detrimental. The fatigue life in dry air was greater than in laboratory air (~50% RH).
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Date Issued: 1989
PURL: http://purl.flvc.org/fcla/dt/14494
Subject Headings: Marine steel--Fatigue, Offshore structures, Sea-water corrosion, Corrosion and anti-corrosives
Format: Document (PDF)

Title: Effect of Polarization on Steel Embedded in Simulated Piling Specimens Evaluated by Critical Chloride Threshold.
Creator: Tanner, Russell, Hartt, William H., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Critical chloride threshold, CT values for initiation of reinforced steel corrosion m mortar typical of Florida coastal bridge substructures were determined in laboratory tests. Previous research has reported CT values that vary by more than an order-of-magnitude, making design life estimation for structures difficult. On this basis, experiments on piling type specimens focused on [Cl-] contamination in the splash zone and coupling of this steel to a large surface area submerged anode. The...
Show moreCritical chloride threshold, CT values for initiation of reinforced steel corrosion m mortar typical of Florida coastal bridge substructures were determined in laboratory tests. Previous research has reported CT values that vary by more than an order-of-magnitude, making design life estimation for structures difficult. On this basis, experiments on piling type specimens focused on [Cl-] contamination in the splash zone and coupling of this steel to a large surface area submerged anode. The lower portion of simulated piling was immersed and the region above the waterline periodically sprayed with NaCI solution. Corrosion potential with respect to height above the waterline was monitored. A temporary depolarization method for determining as to whether or not corrosion had initiated is proposed. Chloride distribution at the reinforcement-concrete interface was determined in piling using energy dispersive x-ray analysis and related to height with respect to the waterline. Chloride threshold was related to corrosion potential.
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Date Issued: 2007
PURL: http://purl.flvc.org/fau/fd/FA00012560
Subject Headings: Reinforced concrete construction, Steel, Structural--Corrosion, Chlorides, Corrosion and anti-corrosives, Seawater corrosion
Format: Document (PDF)

Title: Durability testing of reinforced concrete beams under fatigue loading in a simulated marine environment.
Creator: Ahn, Woo-Suk., Florida Atlantic University, Reddy, Dronnadula V.
Abstract/Description: This thesis addresses the evaluation of the durability of reinforced concrete marine structures subjected to fatigue loading. The laboratory investigation was carried out on full and half size reinforced concrete specimens with three different water cement ratios (0.3, 0.4, and 0.56), static and fatigue loading conditions, and epoxy-coated and regular black steel reinforcements; a mineral admixture (silica fume), and a corrosion inhibitor (calcium nitrite) were used for specimens made with...
Show moreThis thesis addresses the evaluation of the durability of reinforced concrete marine structures subjected to fatigue loading. The laboratory investigation was carried out on full and half size reinforced concrete specimens with three different water cement ratios (0.3, 0.4, and 0.56), static and fatigue loading conditions, and epoxy-coated and regular black steel reinforcements; a mineral admixture (silica fume), and a corrosion inhibitor (calcium nitrite) were used for specimens made with water/cement ratio 0.4 concrete. The marine tidal zone was simulated by alternate filling and draining of the tank (wet and dry cycles), and a galvanostatic corrosion technique to accelerate corrosion of rebar was introduced. Half-cell potentials and changes of crack width were measured periodically during the exposure and followed by ultimate strength testing. The significant findings include adverse effect of fatigue loading, existence of an explicit size effect, poor performance of epoxy coated steel, and negative effect of the increasing water/cement ratio.
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Date Issued: 1995
PURL: http://purl.flvc.org/fcla/dt/15178
Subject Headings: Concrete beams--Fatigue, Underwater concrete construction, Reinforced concrete--Fatigue, Seawater--Corrosion
Format: Document (PDF)

Title: COMPUTER MODELING OF POLARIZATION OF A STEEL PLATE AS A FUNCTION OF TEMPERATURE USING FINITE ELEMENT METHOD.
Creator: VARGHESE, BABU., Florida Atlantic University, Smith, Samuel W., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Computerized modeling techniques have been developed for the analysis of polarization behavior, using the expected chemical reactions and transport phenomena applicable to the formation of calcareous deposits. The method uses the ADINAT finite element heat transfer program and is modeled, as much as possible, on theory rather than laboratory measurements. In contrast, the presently available cathodic protection computer models base their polarization behavior on empirical data. The thesis...
Show moreComputerized modeling techniques have been developed for the analysis of polarization behavior, using the expected chemical reactions and transport phenomena applicable to the formation of calcareous deposits. The method uses the ADINAT finite element heat transfer program and is modeled, as much as possible, on theory rather than laboratory measurements. In contrast, the presently available cathodic protection computer models base their polarization behavior on empirical data. The thesis presents experimental versus theoretical data for a simple flat plate configuration under cathodic protection in natural sea water over a range in temperatures. The flat plate allows for a simplified experimental apparatus and simplifies the derivation of equations for the transport phenomena. The program can, however, handle complex three dimensional geometries. Effects of temperature and flow on the formation and protection of calcareous deposits are also discussed in light of the experimental results.
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Date Issued: 1986
PURL: http://purl.flvc.org/fcla/dt/14314
Subject Headings: Plates, Iron and steel--Cathodic protection, Sea-water corrosion
Format: Document (PDF)

Title: Fatigue crack growth rate of short cracks for high strength steels in sea water.
Creator: Kim, Kijoon., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Experiments have been performed which determined the fatigue crack growth rate (FCGR) of short cracks (a > 0.1mm) for five high strength steels (yield stress 370-570 MPa) in air and in natural seawater with and without cathodic protection. Attention was focused upon Regions I and Il of the classical FCGR-stress intensity range(Delta K) curve with particular consideration of the near-threshold behavior for short cracks. Single edge notch (SEN) three-point bend specimens and a direct current...
Show moreExperiments have been performed which determined the fatigue crack growth rate (FCGR) of short cracks (a > 0.1mm) for five high strength steels (yield stress 370-570 MPa) in air and in natural seawater with and without cathodic protection. Attention was focused upon Regions I and Il of the classical FCGR-stress intensity range(Delta K) curve with particular consideration of the near-threshold behavior for short cracks. Single edge notch (SEN) three-point bend specimens and a direct current potential drop (DCPD) crack monitoring system were employed, and test parameters simulated offshore structure conditions. The results indicated enhanced FCGR for short cracks compared to macrocracks by 3-20 times in air and 2-6 in seawater free-corroding(FC). Also, the Delta Kth for short cracks was apparently lower than for long ones in both environments. The transition from short to long crack behavior occurred at constant $\Delta$K in each environment (15.6 MPa m in air and 10.0 MPa m in seawater(FC)) irrespective of initial Delta K (Delta K(0)). The transition crack length ranged from 0.25 to 1.6 mm and was inversely proportional to $\Delta$K(0). Scanning electron microscope fractography showed that the mechanism of enhanced crack growth rate was associated with secondary crack (SC) formation in air and SC or inter-granular cracking (or both) in seawater (FC). The enhanced FCGR for short cracks was minimized by polarization to -950 mV(SCE). Through an elastic-plastic fracture mechanics analysis using the J-integral parameter it was found that the influence of plastic deformation at the crack tip was approximately independent of crack length (short versus long), and the linear-elastic fracture mechanics analysis gave a realistic representation for fatigue behavior.
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Date Issued: 1992
PURL: http://purl.flvc.org/fcla/dt/12313
Subject Headings: Steel--Fatigue--Environmental aspects, Underwater acoustics, Seawater--Acoustic properties
Format: Document (PDF)

Title: INFLUENCE OF TEMPERATURE ON CALCAREOUS DEPOSIT DEPOSITION UPON CATHODICALLY POLARIZED STEEL IN SEA WATER.
Creator: KUNJAPUR, MADANA MOHAN., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Experiments have been performed where cylindrical 1018 steel specimens were polarized to -0.900 V.(SCE) in natural sea water at 24 and 3C and with rotation speeds of 0 and 0.83 Hz. The nature of the calcareous deposits which formed was characterized, first, by monitoring current density during the experiments and, second, by post-test SEM investigation of deposit morphology and thickness and by EEDS analysis of deposit composition. The dependence of cathodic current density and film...
Show moreExperiments have been performed where cylindrical 1018 steel specimens were polarized to -0.900 V.(SCE) in natural sea water at 24 and 3C and with rotation speeds of 0 and 0.83 Hz. The nature of the calcareous deposits which formed was characterized, first, by monitoring current density during the experiments and, second, by post-test SEM investigation of deposit morphology and thickness and by EEDS analysis of deposit composition. The dependence of cathodic current density and film composition upon temperature and exposure time has been established, and the observed trends have been interpreted in terms of (1) the temperature dependence of the solubility limit and relative nucleation and growth rates for Ca and Mg rich phases and (2) possible electrical conductive behavior on the part of Mg rich deposits.
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Date Issued: 1987
PURL: http://purl.flvc.org/fcla/dt/14377
Subject Headings: Steel--Cathodic protection, Calcium--Effect of temperature on, Seawater
Format: Document (PDF)

Title: An investigation of the influence of surface roughness on reflection coefficients measured by a chirp sonar using a laser profiling of the seafloor.
Creator: Hache, Nicolas., Florida Atlantic University, Beaujean, Pierre-Philippe, Schock, Steven G.
Abstract/Description: This research investigates the validity of an acoustic propagation model by comparing theoretical reflection coefficients, function of frequency, to FAU chirp sonar measurements (chirp sub-bottom profiler). An acoustic model has been implemented to estimate the spectrum of energy reflected from sandy sediments in the presence of surface scattering. The surface roughness being the dominant reverberation part, the volume scattering has been neglected in this model. A laser scanning system...
Show moreThis research investigates the validity of an acoustic propagation model by comparing theoretical reflection coefficients, function of frequency, to FAU chirp sonar measurements (chirp sub-bottom profiler). An acoustic model has been implemented to estimate the spectrum of energy reflected from sandy sediments in the presence of surface scattering. The surface roughness being the dominant reverberation part, the volume scattering has been neglected in this model. A laser scanning system involving an image-processing algorithm has been designed to measure the seafloor bottom roughness using 1D Fourier transforms. In the case of anisotropic roughness, an estimation of the sand ripples dominant direction is provided involving 2D Fourier transforms. Measurements of acoustic data using a chirp sonar and estimation of bottom roughness from video data of the scanner over an artificial bottom are provided to compare the reflection coefficients obtained from the data actually measured with those from the acoustical model.
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Date Issued: 2005
PURL: http://purl.flvc.org/fcla/dt/13212
Subject Headings: Underwater acoustics--Measurement, Marine sediments--Acoustic properties, Oceanography, Seawater--Acoustic properties
Format: Document (PDF)

Title: A comparison of the thermal bleaching response of the zoanthid Palythoa caribaeorum from three geographically different regions in south Florida.
Creator: Kemp, Dustin W., Florida Atlantic University, Cook, Clayton B., Brooks, W. Randy, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Coral bleaching involves the loss of symbiotic algae (zooxanthellae) from reef corals and other cnidarians during periods of environmental stress, particularly elevated temperature. In this study the thermal bleaching responses of the zoanthid Palythoa caribaeorum from three populations along the southeast coast of Florida were compared. Winter (2002--2003) and summer (2003) samples from three geographically separate sites were exposed to increased temperatures and the loss of zooxanthellae...
Show moreCoral bleaching involves the loss of symbiotic algae (zooxanthellae) from reef corals and other cnidarians during periods of environmental stress, particularly elevated temperature. In this study the thermal bleaching responses of the zoanthid Palythoa caribaeorum from three populations along the southeast coast of Florida were compared. Winter (2002--2003) and summer (2003) samples from three geographically separate sites were exposed to increased temperatures and the loss of zooxanthellae was measured. Zooxanthellae populations were sampled and identified using PCR-DGGE. The results showed that samples of P. caribaeorum from reefs that experience smaller annual thermal ranges released the most zooxanthellae. Seasonal comparisons revealed winter samples experienced a greater amount of zooxanthellae loss than summer samples. P. caribaeorum was found to harbor two genetic strains of zooxanthellae, C1 and D1a. Colonies either contained monotypic populations of these, or a combination of both.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/13053
Subject Headings: Zoanthinaria, Seawater--Thermal properties, Zooxanthellales
Format: Document (PDF)

Title: Experimental and theoretical characterization of near-threshold fatigue crack growth for high strength steels in seawater.
Creator: Yang, Jingjun., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Near-threshold fatigue crack growth rate data were generated for six high strength steels at stress ratios of 0.5 and 0.8 under different environmental conditions, which included air, freely corroding in seawater, and cathodically polarized in seawater to -0.80v, -0.95v and -1.10v (vs SCE). The influence of stress ratio, loading frequency, magnitude of cathodic polarization and initial DeltaK on fatigue crack growth behavior for these high strength steels was experimentally characterized. The...
Show moreNear-threshold fatigue crack growth rate data were generated for six high strength steels at stress ratios of 0.5 and 0.8 under different environmental conditions, which included air, freely corroding in seawater, and cathodically polarized in seawater to -0.80v, -0.95v and -1.10v (vs SCE). The influence of stress ratio, loading frequency, magnitude of cathodic polarization and initial DeltaK on fatigue crack growth behavior for these high strength steels was experimentally characterized. The results disclosed general trends of fatigue crack growth under conditions relevant to offshore structure applications and circumscribed variables that are primarily influential with regard to service performance. The rate controlling processes and cracking mechanisms of near-threshold fatigue crack growth, particularly under cathodic polarization in seawater, were also studied in conjunction with crack mouth opening displacement measurements, fractographic observation and crack profile examination. The data and observations suggest that calcareous deposit induced closure was the rate-controlling factor for near-threshold fatigue crack growth under cathodic polarization in seawater although the cracking involved a brittle failure mechanism as a result of hydrogen embrittlement. With different FCGR determining procedures which included natural K-decreasing, enhanced K-decreasing, natural K-increasing and constant DeltaK, the FCGR under cathodic polarization in seawater was found to be time-dependent and, as such, was not a unique function of DeltaK but depended upon K-history or experimental procedures. These observations were consistent with results of a theoretical analysis which involved kinetics modeling of the interaction between fatigue crack growth and calcareous deposit thickening. The model also predicted the existence of an upper limit transition DeltaK, DeltaK Upp/T, between the Paris and threshold regions and it was found that the predicted DeltaK Upp/T was in agreement with the experimental one. The basis for applying this critical parameter (DeltaK Upp/T) to offshore structure designs was addressed in conjunction with experimental results.
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Date Issued: 1995
PURL: http://purl.flvc.org/fcla/dt/12410
Subject Headings: Seawater corrosion, Steel--Fatigue, Steel--Fracture, Corrosion and anti-corrosives
Format: Document (PDF)

Title: Total carbon system automation.
Creator: Clark, A. M.
Date Issued: 1979 - 09 - 06
PURL: http://purl.flvc.org/fcla/dt/3358736
Subject Headings: Carbon, Carbon--Measurement, Seawater--Analysis, Indian River (Fla. : Lagoon), Carbon dioxide--Measurement
Format: Document (PDF)

Title: Strength and Durability of Rice Husk Ash-Modified Concrete in the Marine Environment.
Creator: Alvarez, Marcelina, Reddy, Dronnadula V., Florida Atlantic University
Abstract/Description: The purpose of this research project is to compare the strength and durability characteristics of rice husk ash-modified concrete with those of normal concrete in the marine environment. Specimens prepared from concrete mixes with watercementitious ratios of 0.40 and 0.55, and rice husk ash content of 0%, 10%, and 20% were tested. The rice husk ash used was obtained from Agrilectric, power plant located in Lake Charles, Louisiana. The grinding of the ash to particle size of 7-J..tm to 45-J....
Show moreThe purpose of this research project is to compare the strength and durability characteristics of rice husk ash-modified concrete with those of normal concrete in the marine environment. Specimens prepared from concrete mixes with watercementitious ratios of 0.40 and 0.55, and rice husk ash content of 0%, 10%, and 20% were tested. The rice husk ash used was obtained from Agrilectric, power plant located in Lake Charles, Louisiana. The grinding of the ash to particle size of 7-J..tm to 45-J..tm was done by Process Research ORTECH Inc., Ontario, Canada. Strength and durability tests were performed, following ASTM (American Society for Testing and Materials) Standards. The significant fmdings are that the properties and quality of the rice husk ash-modified concrete are as good, if not better than normal concrete.
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Date Issued: 2006
PURL: http://purl.flvc.org/fau/fd/FA00012502
Subject Headings: Seawater corrosion, Reinforced concrete--Environmental testing, Concrete--Additives, Rice hulls--Testing, Limekilns--Testing
Format: Document (PDF)

FAU Theses and Dissertations (39)	+ -
HBOI Faculty Contributions (12)	+ -
HBOI Technical Reports (3)	+ -

Seawater (15)	+ -
Seawater corrosion (11)	+ -
Sea-water corrosion (10)	+ -
Cathodic protection (7)	+ -
Seawater--Analysis (6)	+ -

Carbon (5)	+ -
Corrosion and anti-corrosives (5)	+ -
Concrete--Corrosion (4)	+ -
Steel--Cathodic protection (4)	+ -
Nitrogen (3)	+ -
Offshore structures (3)	+ -
Seawater--Acoustic properties (3)	+ -
Steel--Fatigue (3)	+ -
Algae culture (2)	+ -
Alloys--Stress corrosion (2)	+ -
Chlorides (2)	+ -
Concrete--Deterioration (2)	+ -
Gracilaria (2)	+ -
Leaching (2)	+ -
Marine steel (2)	+ -
Phosphorus (2)	+ -
Seawater Corrosion (2)	+ -
Seawater--Analysis--Automation (2)	+ -
Seawater--Thermal properties (2)	+ -
Steel--Corrosion (2)	+ -
Steel--Fracture (2)	+ -
Stress corrosion (2)	+ -
Underwater acoustics (2)	+ -
Zooxanthellales (2)	+ -
Adhesives (1)	+ -

Electronic Thesis or Dissertation (39)	+ -
article (12)	+ -
technical report (3)	+ -

Florida Atlantic University (39)	+ -
College of Engineering and Computer Science (23)	+ -
Department of Ocean and Mechanical Engineering (22)	+ -
Hartt, William H. (18)	+ -
Harbor Branch Oceanographic Institute (7)	+ -

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