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Pages
- Title
- INFLUENCE OF DISSOLVED ORGANICS IN SEA WATER ON THE CORROSION BEHAVIOR OF SELECTED METALS.
- Creator
- MACDOWELL, LOUIS GARDNER, III, Florida Atlantic University
- Abstract/Description
-
Corrosion experiments have been performed upon steel and copper in natural sea water, photo-oxidized sea water and 3.5% sodium chloride-distilled water solutions. Anodic and cathodic polarization scans were conducted, and the resulting curves were employed to characterize corrosion behavior in each of the electrolytes. While little difference as a function of electrolyte was noted for tests upon copper, variations were apparent in the case of steel. The effect of environment has been...
Show moreCorrosion experiments have been performed upon steel and copper in natural sea water, photo-oxidized sea water and 3.5% sodium chloride-distilled water solutions. Anodic and cathodic polarization scans were conducted, and the resulting curves were employed to characterize corrosion behavior in each of the electrolytes. While little difference as a function of electrolyte was noted for tests upon copper, variations were apparent in the case of steel. The effect of environment has been interpreted in terms of differences in organics adsorbed upon the metal surface from one electrolyte to the next. Significance of adsorbed organics upon corrosion rate of steel in sea water is discussed.
Show less - Date Issued
- 1979
- PURL
- http://purl.flvc.org/fcla/dt/13957
- Subject Headings
- Seawater corrosion
- Format
- Document (PDF)
- Title
- Automation of nutrient determinations in seawater using a technicon autoanalyer interfaced to an Apple II microcomputer/ISAAC data acquisition system.
- Creator
- Montgomery, John R., McKim, J. M., Jr., Harbor Branch Oceanographic Institute
- Date Issued
- 1983
- PURL
- http://purl.flvc.org/FCLA/DT/3183669
- Subject Headings
- Seawater--Analysis, Seawater--Analysis--Automation
- Format
- Document (PDF)
- Title
- Hydrogen generation from sea water by meansof a metal hydrolysis process.
- Creator
- Wang, Tsen C., Tan, C. K., Harbor Branch Oceanographic Institute
- Date Issued
- 1990
- PURL
- http://purl.flvc.org/fau/fd/FA00007251
- Subject Headings
- Seawater, Hydrolysis, Hydrogen, Metals
- Format
- Document (PDF)
- Title
- FATIGUE OF HIGH STRENGTH LOW-ALLOY STEELS IN NATURAL SEA WATER.
- Creator
- KRISHNAKUMAR, RENGAN., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The fatigue response of selected high strength low alloy steels, that are under consideration for future offshore structural applications, was investigated. Freely corroding and cathodically polarized experiments were conducted under conditions relevant .to these applications. Cathodic polarization experiments involved testing of A537 Direct Quenched (A537 DQ) steel at different potentials in the -0.80 V to -1.10 V (SCE) range. The damage to freely corroding high strength steel was more than...
Show moreThe fatigue response of selected high strength low alloy steels, that are under consideration for future offshore structural applications, was investigated. Freely corroding and cathodically polarized experiments were conducted under conditions relevant .to these applications. Cathodic polarization experiments involved testing of A537 Direct Quenched (A537 DQ) steel at different potentials in the -0.80 V to -1.10 V (SCE) range. The damage to freely corroding high strength steel was more than on structural steel for calculations based on the Wirsching wide band spectrum. Polarization to -0.80 V (SCE) improved the fatigue life of A537 DQ steel over the freely corroding life. A definite conclusion with regard to the influence of different levels of cathodic polarization on the fatigue life of the steel investigated can not not be drawn based on the results from this study due to data variability.
Show less - Date Issued
- 1987
- PURL
- http://purl.flvc.org/fcla/dt/14374
- Subject Headings
- Steel--Fatigue, Seawater
- Format
- Document (PDF)
- Title
- FREQUENCY DEPENDENCE OF SEA WATER CORROSION FATIGUE OF NOTCHED 1018 STEEL.
- Creator
- HENKE, THOMAS ELMER, Florida Atlantic University
- Abstract/Description
-
Experiments were conducted to investigate frequency dependence of sea water corrosion fatigue of notched 1018 steel under constant deflection, reverse bend test conditions. Frequencies of 1850, 1200, and 600 cycles per minute (CPM) were studied. Results indicate that frequency effects are not observed at high stresses, apparently due to the mechanical damage component of the fatigue process dominating over corrosion considerations. At low stresses reduced frequency resulted in decreased...
Show moreExperiments were conducted to investigate frequency dependence of sea water corrosion fatigue of notched 1018 steel under constant deflection, reverse bend test conditions. Frequencies of 1850, 1200, and 600 cycles per minute (CPM) were studied. Results indicate that frequency effects are not observed at high stresses, apparently due to the mechanical damage component of the fatigue process dominating over corrosion considerations. At low stresses reduced frequency resulted in decreased cycles to failure. Acidification of the crack tip solution is proposed as possibly responsible for this behavior. For specimens subjected to equal stress levels in the frequency dependent region, greater cathodic protection is required to mitigate corrosion fatigue for 600 CPM specimens (-0.86 volts standard calomel electrode) (V SCE) than for 1850 CPM specimens (-079V SCE).
Show less - Date Issued
- 1975
- PURL
- http://purl.flvc.org/fcla/dt/13731
- Subject Headings
- Steel--Corrosion, Seawater
- Format
- Document (PDF)
- Title
- Operation, methods, and quality control of Technicon AutoAnalyzer II Systems for nutrient determinations in seawater.
- Creator
- Zimmermann, Carl F., Price, Mary T., Montgomery, John R.
- Date Issued
- 1977-02
- PURL
- http://purl.flvc.org/fcla/dt/3358479
- Subject Headings
- Estuaries, Micronutrients, Seawater--Analysis
- Format
- Document (PDF)
- Title
- THE CORROSION OF EPOXY COATED REINFORCING STEEL.
- Creator
- WANG, YUN TSO, Florida Atlantic University
- Abstract/Description
-
Tests were conducted using 10 cm. (3.93 in.) lengths of both epoxy coated and bare steel reinforcing rods in simulated concrete environments of varying pH and chloride ion levels. Polarization studies using cathodic scan techniques were used to characterize the quality of the epoxy coating. In all the environments tested, bars with more defects required larger currents at a given potential than did the bars with few defects. Corrosion potential measurements in passive environments showed...
Show moreTests were conducted using 10 cm. (3.93 in.) lengths of both epoxy coated and bare steel reinforcing rods in simulated concrete environments of varying pH and chloride ion levels. Polarization studies using cathodic scan techniques were used to characterize the quality of the epoxy coating. In all the environments tested, bars with more defects required larger currents at a given potential than did the bars with few defects. Corrosion potential measurements in passive environments showed significant fluctuations from day to day, making it difficult to use potential measurement for corrosion characterization. Galvanic couples between epoxy coated and uncoated bars indicated that galvanic currents increased as the differences in the corrosion potentials increased and also as the chloride ion content of the environment increased from 0 to 0.05 M.
Show less - Date Issued
- 1980
- PURL
- http://purl.flvc.org/fcla/dt/14010
- Subject Headings
- Concrete--Corrosion, Seawater Corrosion
- Format
- Document (PDF)
- Title
- INVESTIGATION OF CORROSION OF REINFORCING STEEL BY USING ULTRASONIC TECHNIQUES AND SPECTRAL ANALYSIS.
- Creator
- WANG, YUN YU, Florida Atlantic University
- Abstract/Description
-
In this investigation an ultrasonic technique and spectral analysis were employed to detect corrosion of reinforcing steel in concrete under conditions of accelerated testing. Various properties of a transmitted ultrasonic pulse were determined, and it was concluded that the transfer function provided the most realistic possibility for detection of corrosion and cracking. The most meaningful correlations of the transfer function with corrosion and cracking events were for situations where the...
Show moreIn this investigation an ultrasonic technique and spectral analysis were employed to detect corrosion of reinforcing steel in concrete under conditions of accelerated testing. Various properties of a transmitted ultrasonic pulse were determined, and it was concluded that the transfer function provided the most realistic possibility for detection of corrosion and cracking. The most meaningful correlations of the transfer function with corrosion and cracking events were for situations where the temporal variation of the transfer function at the particular frequency was small. The appropriateness of ultrasonic parameters with regard to problems involving corrosion of reinforcing steel is discussed.
Show less - Date Issued
- 1979
- PURL
- http://purl.flvc.org/fcla/dt/14006
- Subject Headings
- Concrete--Corrosion, Seawater Corrosion
- Format
- Document (PDF)
- Title
- STRUCTURAL INTEGRITY OF CALCAREOUS DEPOSIT - REHABILITATED MARINE REINFORCED CONCRETE.
- Creator
- DOHLEN, STENER., Florida Atlantic University
- Abstract/Description
-
Corrosion-induced spalling of reinforced concrete and prestressed concrete is a major problem in coastal structures. Statistics on the rehabilitation and replacement of damaged concrete in the U.S.A. indicates substantial expenditure. This study is an investigation of the use of electro-deposited minerals for in-situ concrete repair in a cost-effective manner to extend the service life for marine reinforced concrete structures. During the first phase of this investigation, the reinforcing...
Show moreCorrosion-induced spalling of reinforced concrete and prestressed concrete is a major problem in coastal structures. Statistics on the rehabilitation and replacement of damaged concrete in the U.S.A. indicates substantial expenditure. This study is an investigation of the use of electro-deposited minerals for in-situ concrete repair in a cost-effective manner to extend the service life for marine reinforced concrete structures. During the first phase of this investigation, the reinforcing steel in specimens was corroded by an impressed voltage technique to a point where concrete cracking occurred. The second phase addressed the rehabilitation in which the calcareous deposits were precipitated in the cracks by an impressed cathodic current. This investigation included both laboratory testing with once-through circulating seawater and field testing in the ocean environment. The findings indicate that the structural strength of the concrete specimens decreased as a result of the impressed voltage.
Show less - Date Issued
- 1988
- PURL
- http://purl.flvc.org/fcla/dt/14407
- Subject Headings
- Reinforced concrete--Cracking, Seawater
- Format
- Document (PDF)
- Title
- An automated system of sample analysis for a total carbon analyser.
- Creator
- Fitzgerald, L., Montgomery, John R., Holt, John K., Harbor Branch Oceanographic Institute
- Date Issued
- 1984
- PURL
- http://purl.flvc.org/FCLA/DT/3351926
- Subject Headings
- Carbon, Seawater--Analysis, Seawater--Analysis--Automation, Seawater--Carbon dioxide content
- Format
- Document (PDF)
- Title
- Elemental composition of the coral Pocillopora damicornis exposed to elevated seawater ammonium.
- Creator
- Muller-Parker, Gisèle, Cook, Clayton B., D'Elia, C. F.
- Date Issued
- 1994
- PURL
- http://purl.flvc.org/fau/fd/FA00007225
- Subject Headings
- Corals, Zooxanthellales, Ammonium, Seawater, Nitrogen, Phosphorus, Carbon
- Format
- Document (PDF)
- Title
- The effects of nitrogen and seawater flow rate on the growth and biochemical composition of Gracilaria foliifera var. angustissima in mass outdoor cultures.
- Creator
- Lapointe, Brian E., Ryther, John H.
- Date Issued
- 1979
- PURL
- http://purl.flvc.org/fau/fd/FA00007004
- Subject Headings
- Gracilaria, Nitrogen, Seawater, Growth, Biochemistry, Algae culture
- Format
- Document (PDF)
- Title
- Effects of seawater phosphorus concentration on Floridean starch content in Agardhiella subulata (C. Agardh) Kraft et Wynne (Rhodophyceae).
- Creator
- Chopin, T., Hanisak, M. Dennis, Koehn, F. E.
- Date Issued
- 1991
- PURL
- http://purl.flvc.org/fau/fd/FA00007025
- Subject Headings
- Polysaccharides, Rhodophyceae, Red algae, Seawater, Phosphorus
- Format
- Document (PDF)
- Title
- Characterization and Modeling of Profiling Oceanographic Lidar for Remotely Sampling Ocean Optical Properties.
- Creator
- Strait, Christopher, Nayak, Aditya, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
- Abstract/Description
-
Lidar has the ability to supplant or compliment many current measurement technologies in ocean optics. Lidar measures Inherent Optical Properties over long distances without impacting the orientation and assemblages of particles it measures, unlike many systems today which require pumps and flow cells. As an active sensing technology, it has the benefit of being independent of time of day and weather. Techniques to interpret oceanographic lidar lags behind atmospheric lidar inversion...
Show moreLidar has the ability to supplant or compliment many current measurement technologies in ocean optics. Lidar measures Inherent Optical Properties over long distances without impacting the orientation and assemblages of particles it measures, unlike many systems today which require pumps and flow cells. As an active sensing technology, it has the benefit of being independent of time of day and weather. Techniques to interpret oceanographic lidar lags behind atmospheric lidar inversion techniques to measure optical properties due to the complexity and variability of the ocean. Unlike in the atmosphere, two unknowns in the lidar equation backscattering at 180o (𝛽𝜋) and attenuation (c) do not necessarily covary. A lidar system developed at the Harbor Branch Oceanographic Institute is used as a test bed to validate a Monte-Carlo model to investigate the inversion of optical properties from lidar signals. Controlled tank experiments and field measurements are used to generate lidar waveforms and provide optical situations to model. The Metron EODES backscatter model is used to model waveforms. A chlorophyll based forward optical model provides a set of 1500 unique optical situations which are modeled to test inversion techniques and lidar geometries. Due to issues with the lidar system and model the goal of validating the model as well as a more mature inversion experiment were not completed. However, the results are valuable to show the complexity and promise of lidar systems.
Show less - Date Issued
- 2020
- PURL
- http://purl.flvc.org/fau/fd/FA00013631
- Subject Headings
- Lidar, Remote sensing, Seawater--Optical properties
- Format
- Document (PDF)
- Title
- CHARACTERIZATION OF THE EMBRITTLEMENT TENDENCY OF A CATHODICALLY POLARIZED SUPERFERRITIC STAINLESS STEEL IN SEAWATER (HYDROGEN DAMAGE, INTERGRANULAR).
- Creator
- KRISHNAMURTHY, RAVI M., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
In order to investigate the cracking tendency of cathodically polarized SEACURE superferritic stainless steel, a series of potentiostatically controlled tests were conducted in flowing natural seawater. U-bend and tensile specimens were used to determine the threshold potential and limiting fracture stress. The microstructure was examined using a metallurgical microscope and a chemical analysis was conducted across the grain boundary. These results were then correlated to hydrogen assisted...
Show moreIn order to investigate the cracking tendency of cathodically polarized SEACURE superferritic stainless steel, a series of potentiostatically controlled tests were conducted in flowing natural seawater. U-bend and tensile specimens were used to determine the threshold potential and limiting fracture stress. The microstructure was examined using a metallurgical microscope and a chemical analysis was conducted across the grain boundary. These results were then correlated to hydrogen assisted cracking, by performing SEM and EDAX analyses on fractured U-bend and tensile samples. Finally a model was developed which explained the predominantly intergranular cracking in the static stress condition and also accommodated the transgranular failure during dynamic loading.
Show less - Date Issued
- 1986
- PURL
- http://purl.flvc.org/fcla/dt/14325
- Subject Headings
- Steel--Fracture, Sea-water corrosion
- Format
- Document (PDF)
- Title
- Cathodic polarization behavior of mild steel exposed to selected flow velocities and slope parameters in natural seawater.
- Creator
- Hugus, G. Dickson, IV., Florida Atlantic University, Hartt, William H.
- Abstract/Description
-
Twenty-four test cells arranged in a pipe flow setup were assembled to investigate the effect of seawater velocity on the polarization behavior of galvanically polarized mild steel. Each 1023 steel pipe specimen of 10.8 em ID was coupled via a current limiting resistor to a mercury activated aluminum anode and exposed to a velocity of either 0.03, 0.09 or 0.30 m/s. The resistors were sized such that polarization was controlled according to one of six slope parameters. Steady state potential...
Show moreTwenty-four test cells arranged in a pipe flow setup were assembled to investigate the effect of seawater velocity on the polarization behavior of galvanically polarized mild steel. Each 1023 steel pipe specimen of 10.8 em ID was coupled via a current limiting resistor to a mercury activated aluminum anode and exposed to a velocity of either 0.03, 0.09 or 0.30 m/s. The resistors were sized such that polarization was controlled according to one of six slope parameters. Steady state potential and maintenance current density values were determined, and a steady state potential vs. current density curve was established for specimens in each velocity. Some specimens experienced a rise in cathode potential and current density after an apparent steady state had been reached. This was probably related to the influence of velocity on the protectiveness of the calcareous deposit. Of the specimens that experienced a rise in steady state potential and current density, a few were later observed to decrease in potential and current density and reach steady state. Steady state current density vs. velocity plots of specimens at steady state potentials of -0.78, -0.88 and -0.98 V showed that current density was directly proportional to velocity as well as relatively insensitive to potential. Ficks' first law was utilized in conjunction with an empirically derived dimensionless correlation that characterizes the behavior between fluid velocity and mass transfer of molecular species from the bulk solution to the cathode surface in turbulent seawater pipe flow. Calcareous deposit porosity constants were calculated and it was surmised that as velocity increased by a factor of three, the porosity of the deposits near 0.78 and -0.89 V increased by multiples of about two on average. Porosity at the above potentials increased with decreasing potential by a factor of a little over two. SEM micrographs were made and EDX analyses were performed on the calcareous deposits of selected specimens.
Show less - Date Issued
- 1997
- PURL
- http://purl.flvc.org/fcla/dt/15501
- Subject Headings
- Cathodic protection, Seawater corrosion, Marine steel
- Format
- Document (PDF)
- Title
- Characterization of steel cathodic polarization in seawater and its applications in offshore structure cathodic protection design.
- Creator
- Wang, Weiqing., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Laboratory experiments have been performed to characterize the effects of initial current density and selected variables (initial current density, temperature and surface treatment) upon the cathodic polarization behavior of API 2H Grade 42 steel in natural sea water. The procedure involved galvanic coupling of a cylindrical steel specimen to a larger diameter aluminum sacrificial anode ring through an external resistor, which offset the otherwise impractically small anode/cathode surface...
Show moreLaboratory experiments have been performed to characterize the effects of initial current density and selected variables (initial current density, temperature and surface treatment) upon the cathodic polarization behavior of API 2H Grade 42 steel in natural sea water. The procedure involved galvanic coupling of a cylindrical steel specimen to a larger diameter aluminum sacrificial anode ring through an external resistor, which offset the otherwise impractically small anode/cathode surface area ratio and permitted the desired initial current density to be realized. In the initial polarization stage the change in potential versus current density data with time was found to be linear with a slope equal to the product of the total circuit resistance and cathode surface area and with the vertical intercept corresponding to the anode open circuit potential. Lower temperature or increased flow resulted in reduced polarization and a relatively high current density, but data for experiments employing a particular resistance conformed to straight lines with the same slope R[ext] x A[c] (external resistance times cathode surface area). Some experiments exhibited concave behavior at longer test duration. An explanation for the linear interdependence of potential and current density and the following concave behavior is presented. The laboratory experiments were compared with offshore structure survey results. It is projected that the potential-current density behavior of galvanic cathodic protection (CP) systems of different geometries can be quantitatively interrelated through this slope parameter. Implications of the data are discussed within the context of cathodic protection design, rapid polarization and system performance for offshore structures.
Show less - Date Issued
- 1994
- PURL
- http://purl.flvc.org/fcla/dt/12362
- Subject Headings
- Steel--Cathodic protection, Seawater, Offshore structures
- Format
- Document (PDF)
- Title
- Steel cathodic polarization and calcareous deposit characteristics in deep seawater.
- Creator
- Chen, Shaowei., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Field and laboratory ambient and simulated deep seawater sacrificial anode cathodic protection experiments were performed by coupling steel specimens to Al-Zn-Hg anode through an appropriately sized external resistor and thereby permitting a particular level of cathodic protection from freely corroding to overprotection to be simulated. The effects of sea current velocity, surface preparation, initial current density, temperature and hydrostatic pressure upon cathodic polarization and...
Show moreField and laboratory ambient and simulated deep seawater sacrificial anode cathodic protection experiments were performed by coupling steel specimens to Al-Zn-Hg anode through an appropriately sized external resistor and thereby permitting a particular level of cathodic protection from freely corroding to overprotection to be simulated. The effects of sea current velocity, surface preparation, initial current density, temperature and hydrostatic pressure upon cathodic polarization and characteristics of calcareous deposits were investigated in the context of slope parameter and steady-state potential and current density trend. The results revealed that a linear relationship between cathode potential and current density is applicable for design of sacrificial anode cathodic protection systems and analysis of cathodic protection survey data from existing structures both in shallow and deep waters. It was also found that for cathodically polarized steel specimens in ambient (shallow) seawater steady-state cathode potential and current density varied according to a sigmoidal trend that indicates the importance of calcareous deposits in such exposures and demonstrated the utility of rapid polarization. On the other hand, no sigmoidal trend was apparent for field and simulated deep water tests; but instead steady-state current density was constant for potential range between -0.80 and -1.05 v (Ag/AgCl). This disclosed that no particular benefit could be derived from employing rapid polarization in cold water exposures. SEM, EDX and X-ray diffraction analysis revealed that the calcareous deposits formed upon specimens exposed at 5C and ambient pressure or 8.96 MPa laboratory experiments exhibited two layer structures--an outer layer of CaCO3 as aragonite and inner layer of Mg(OH)2 as brucite. The morphology and coverage of the deposits depended on the design slope parameter (initial current density). Field testing results indicated that deposits were also composed of CaCO3 and Mg(OH)2 where the former was calcite. Because of the poor coverage of the deposits formed in the deep water condition, limited current density reduction was noted. These results suggest that a different cp design approach and strategy should be considered for deep, cold seawater compared to that commonly used in shallow water environments.
Show less - Date Issued
- 1996
- PURL
- http://purl.flvc.org/fcla/dt/12457
- Subject Headings
- Seawater corrosion, Cathodic protection, Steel--Corrosion
- Format
- Document (PDF)
- Title
- Thermodynamic analysis of the influences of temperature and pressure on deep sea cathodic protection criterion.
- Creator
- Wang, Weiqing., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Knowledge of the reversible potential for corrosion reaction under condition of deep sea exposure and how this is influenced by parameters such as temperature and pressure is of importance to the understanding and design of deep sea cathodic protection systems, since this potential is used as the cathodic protection criterion. Also, if the polarized potential is more negative than the reversible potential of the hydrogen reaction, then hydrogen embrittlement may occur. Thermodynamic analysis...
Show moreKnowledge of the reversible potential for corrosion reaction under condition of deep sea exposure and how this is influenced by parameters such as temperature and pressure is of importance to the understanding and design of deep sea cathodic protection systems, since this potential is used as the cathodic protection criterion. Also, if the polarized potential is more negative than the reversible potential of the hydrogen reaction, then hydrogen embrittlement may occur. Thermodynamic analysis methods are used to calculate Gibbs free energy change and reversible potential of reactions involved in cathodic protection of steel for temperatures and pressures typical of deep sea. Based on the assumptions employed it is found that the reversible potential for the iron reaction becomes less negative with depth for the first 1000m and remains approximately constant beyond this.
Show less - Date Issued
- 1989
- PURL
- http://purl.flvc.org/fcla/dt/14515
- Subject Headings
- Steel--Cathodic protection, Seawater--Thermodynamics
- Format
- Document (PDF)
- Title
- Leaching characteristics of lead and cadmium from waste-to-energy residues in sea water.
- Creator
- Shieh, C-S., Wei, Y-L., Duedall, I. W., Wang, Tsen C., Harbor Branch Oceanographic Institute
- Date Issued
- 1992
- PURL
- http://purl.flvc.org/FCLA/DT/3352921
- Subject Headings
- Leaching, Lead, Cadmium, Seawater, Waste disposal in the ocean, Incineration
- Format
- Document (PDF)
