The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Geert Potters - One of the best experts on this subject based on the ideXlab platform.
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Assessment of corrosion resistance, material properties, and weldability of alloyed steel for Ballast Tanks
Journal of Marine Science and Technology, 2017Co-Authors: Kris De Baere, Helen Verstraelen, Silvia Lenaerts, Remke Willemen, Jean-pierre Smet, Jérôme Tchoufang Tchuindjang, Jacqueline Lecomte-beckers, Raf Meskens, Hwan Gyo Jung, Geert PottersAbstract:Ballast Tanks are of great importance in the lifetime of modern merchant ships. Making a Ballast tank less susceptible to corrosion can, therefore, prolong the useful life of a ship and, thereby, lower its operational cost. An option to reinforce a Ballast tank is to construct it out of a corrosion-resistant steel type. Such steel was recently produced by POSCO Ltd., South Korea. After 6 months of permanent immersion, the average corrosion rate of A and AH steel (31 samples) was 535 g m^−2 year^−1, while the Korean CRS was corroding with 378 g m^−2 year^−1. This entails a gain of 29 %. Follow-up measurements after 10, 20, and 24 months confirmed this. The results after 6 months exposure to alternating wet/dry conditions are even more explicit. Furthermore, the physical and metallurgical properties of this steel show a density of 7.646 t/m^3, the elasticity modulus 209.3 GPa, the tensile strength 572 MPa, and the hardness 169HV10. Microscopically, the metal consists of equiaxed and recrystallized grains (ferrite and pearlite), with an average size of between 20 and 30 µm (ASTM E 112—12 grain size number between 7 and 8) with a few elongated pearlitic grains. The structure is banded ferrite/pearlite. On the basis of a series of energy dispersive X-ray spectrometer measurements the lower corrosion rate of the steel can be attributed to the interplay of Al, Cr, their oxides, and the corroding steel. In addition, the role of each element in the formation of oxide layers and the mechanisms contributing to the corrosion resistance are discussed.
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A field study of the effectiveness of sacrificial anodes in Ballast Tanks of merchant ships
Journal of Marine Science and Technology, 2014Co-Authors: Kris De Baere, Helen Verstraelen, Raf Dewil, Silvia Lenaerts, Lucien Lemmens, Yves Ingelgem, Geert PottersAbstract:Sacrificial anodes have become a standard practice for the protection of Ballast Tanks of merchant vessels against corrosive damage. A well protected tank should extend the life span of a ship and consequently enhances its economic value. An in situ survey comprising more than 100 merchant vessels provided the opportunity to measure the impact of these anodes on the life expectancy of these vessels. Contrary to the general belief of these anodes’ beneficial effect, no significant difference was found in our observations in terms of corrosion occurrence between ship populations with and without sacrificial anodes, across all ship ages. This may be explained by the highly variable conditions and the complex geometry in a Ballast tank severely impede optimal and straightforward installation of these anodes in these Tanks. Also, poorly placed anodes in it may harm the integrity of the coating of the tank. We therefore plead for uniform and clear rules on anode installation and inspection.
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Impact of tank construction on corrosion of ship Ballast Tanks
Materials Performance, 2010Co-Authors: Kris De Baere, Helen Verstraelen, Raf Dewil, L. F. Lemmens, Silvia Lenaerts, Tharcisse Nkunzimana, Geert PottersAbstract:Many elements influence corrosion in Ballast Tanks on merchant vessels. Ballast Tanks on more than 100 vessels were inspected and corrosion rates were evaluated following a standard procedure. Statistical interpretation of the data led to conclusions on the influence of elements such as ship length, sailing area, type of coating, type of vessel, and country of construction.
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In Situ Study of Ballast Tank Corrosion on Ships-Part 2
Materials Performance, 2009Co-Authors: Helen Verstraelen, Kris De Baere, Raf Dewil, L. F. Lemmens, Silvia Lenaerts, Willy Schillemans, Geert PottersAbstract:A study was undertaken to determine causes and effects of corrosion processes in Ballast Tanks. Part 1 of this article (October 2009 MP) described the data collection. Part 2 describes the development of a corrosion index (CI) derived from the general International Association of Classification Societies corrosion assessment methods. The CI can be used in situ to assess Ballast tank corrosion. An average timeline for corrosion of Tanks is presented.
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In situ study of Ballast tank corrosion on ships. Part 1
Materials Performance, 2009Co-Authors: Helen Verstraelen, Kris De Baere, Raf Dewil, L. F. Lemmens, Silvia Lenaerts, Willy Schillemans, Geert PottersAbstract:A study was undertaken to determine causes and effects of corrosion processes in Ballast Tanks. Part 1 of this article describes the data collection and Part 2 (November 2009 MP) explains the development of a refined corrosion index to determine an average tirneline for corrosion of Tanks.
Sarah A. Bailey - One of the best experts on this subject based on the ideXlab platform.
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Improving estimation of phytoplankton abundance and distribution in Ballast water discharges
Journal of Applied Phycology, 2020Co-Authors: Oscar Casas-monroy, Harshana Rajakaruna, Sarah A. BaileyAbstract:With the International Maritime Organization’s (IMO) International Convention for the Control and Management of Ships’ Ballast Water and Sediments now in force, determining abundance and distribution of phytoplankton inside Ballast Tanks is critical for successful Ballast water management, particularly when assessing compliance. The relationship between the abundance and distribution of cells was examined to obtain the best representative sample of the entire phytoplankton community in Ballast Tanks, comparing three Ballast water sampling techniques including in-line, in-tank, and Van Dorn bottle methods. Lloyd’s index, D_ y , and Gini index were applied to compare methods of sample collection and determine representativeness of samples and performance of sampling methods. Phytoplankton abundance trends from live microscopy counts using fluorescein diacetate (FDA) were also compared to those using a FlowCAM on preserved samples. The phytoplankton community showed a patchy distribution inside the Ballast tank and this trend was observed across all voyages. The estimated marginal mean analysis showed that in hypothetical conditions (e.g., 702 m^3 of water in Ballast tank and phytoplankton whole-tank abundance of 19,522 cells), the difference among the three methods was small. Conversely, statistical analysis performed on empiric abundances using a negative binomial regression model determined that the volume discharged during sampling of Ballast water has an effect on the number of cells collected on a given voyage. Results of this study also confirmed that the in-line method may be a better method at collecting phytoplankton samples from Ballast Tanks than the in-tank or Van Dorn method, regardless of the time at which samples are collected. Finally, the number of living cells and the number of preserved cells showed similar trends for most of the voyages, despite fewer samples analyzed using FDA.
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Optimizing methods to estimate zooplankton concentration based on generalized patterns of patchiness inside Ballast Tanks and Ballast water discharges.
Ecology and evolution, 2017Co-Authors: Sarah A. Bailey, Harshana RajakarunaAbstract:Zooplankton populations are spatially heterogeneous in nature and inside ship Ballast Tanks. Sampling methods should take heterogeneity into account, particularly when estimating quantitative variables such as abundance or concentration. It is particularly important to generate unbiased estimates of zooplankton concentration in Ballast water when assessing compliance with new international Ballast water discharge standards. We measured spatial heterogeneity of zooplankton within Ballast water using three sampling methodologies. In-tank pump samples were collected at fixed depths within the vertical part of the Ballast tank (side tank). Vertical net-haul samples were collected from the upper portion of the tank as a depth-integrated and historically relevant method. In-line, time-integrated samples were collected during Ballast discharge by an isokinetic sample probe, likely representing the double bottom part of the Ballast tank. The bias and precision associated with each sampling method were evaluated in reference to the estimated average abundance of the entire Ballast tank, which was modeled from the data collected by all methods. In-tank pump samples provided robust evidence for vertical stratification of zooplankton concentration in the side tank. A consistent trend was also observed for in-line discharge samples, with zooplankton concentration decreasing through time as the Ballast tank is being discharged. Sample representativeness, as compared to the tank average, varied depending on the depth or tank volume discharged. In-line discharge samples provided the least biased and most precise estimate of average tank abundance (having lowest mean squared error) when collected during the time frame of 20%-60% of the tank volume being discharged. Results were consistent across five trips despite differences in Ballast water source, season, and age.
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Invasion risk posed by macroinvertebrates transported in ships’ Ballast Tanks
Biological Invasions, 2012Co-Authors: Elizabeta Briski, Sarah A. Bailey, Sara Ghabooli, Hugh J. MacisaacAbstract:Invasions by non-indigenous macroinvertebrates often cause ecological and economic problems, and commercial ships have been implicated as a principal mechanism for their dispersal. We explored the presence and species diversity of adult macroinvertebrates transported by transoceanic and coastal vessels arriving to ports on the Atlantic coast of Canada. We sampled 67 Ballast Tanks from 62 ships operating along discrete geographic pathways and tested whether mid-ocean exchange or voyage length affects the probability for translocation of macroinvertebrates. Additionally, we assessed the relationship between macroinvertebrate presence and the amount of sediment in Ballast Tanks. We document the presence of highly invasive European green crab ( Carcinus maenas ), mud crab ( Rhithropanopeus harrisii ), common periwinkle ( Littorina littorea ), soft shell clam ( Mya arenaria ) and blue mussel ( Mytilus galloprovincialis ) in Ballast Tanks of surveyed ships. Mid-ocean exchange did not affect macroinvertebrate occurrence, suggesting that current Ballast water management regulations are ineffective for this taxonomic group. Viable individuals were recorded in vessels undertaking shorter voyages (average and maximum of 4.5 and 15 days, respectively) and presence was not related to the amount of sediment in Tanks. While presence and densities of macroinvertebrates were low, invasion risk may nonetheless be significant during reproductive seasons owing to high fecundity of some taxa. The highest risk may be posed by decapods since gravid females may carry thousands to several million eggs per clutch, and after several weeks of brooding, two or more subsequent clutches may be fertilized by retained sperm from an earlier mating.
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Brine-induced mortality of non-indigenous invertebrates in residual Ballast water
Marine Environmental Research, 2010Co-Authors: Johanna N. Bradie, Sarah A. Bailey, Gerard Van Der Velde, Hugh J. MacisaacAbstract:All transoceanic vessels entering the Great Lakes are required to manage Ballast water and Ballast tank residuals with Ballast water exchange and tank flushing, respectively. While these management procedures effectively reduce the density and richness of biota in Ballast waters and thereby reduce the risk of transferring non-indigenous species, some ships are unable to uniformly manage all Tanks. Laboratory experiments were conducted to evaluate sodium chloride brine as an emergency treatment for Ballast Tanks with non-compliant residuals. Invertebrate communities collected from i) Detroit River, ii) exchanged Ballast Tanks arriving in the Great Lakes, and iii) North Sea ports, were exposed to a range of brine concentrations (15‰-115‰) until complete mortality was reached. Results indicate that a one-hour exposure to 115‰ brine is a broadly effective treatment (>99.9% mortality) regardless of treatment temperature, taxonomic group, or species' source habitat salinity. A median of 0.00% (range 0.00-5.33) of individuals are expected to survive treatment and the expected number of viable individuals released after treatment is within Canadian and proposed international discharge standards. Before implementation, validation with ship-scale trials is recommended.
Tom Bebbington - One of the best experts on this subject based on the ideXlab platform.
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ICCL - An accurate model for seaworthy container vessel stowage planning with Ballast Tanks
Lecture Notes in Computer Science, 2012Co-Authors: Dario Pacino, Rune Møller Jensen, Alberto Delgado, Tom BebbingtonAbstract:Seaworthy container vessel stowage plans generated under realistic assumptions are a key factor for stowage decision support systems in the shipping industry. We propose a linear model with Ballast Tanks for generating master plans, the first phase of a 2-phase stowage optimization approach, that includes the main stability and stress moments calculations. Our approach linearizes the center of gravity calculation and hydrostatic data tables of the vessel in order to formulate stability and stress moments constraints that can handle variable displacement. The accuracy level of these linearizations is evaluated when the displacement of the vessel is allowed to change within a small band.
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an accurate model for seaworthy container vessel stowage planning with Ballast Tanks
International Conference on Computational Logistics, 2012Co-Authors: Dario Pacino, Rune Møller Jensen, Alberto Delgado, Tom BebbingtonAbstract:Seaworthy container vessel stowage plans generated under realistic assumptions are a key factor for stowage decision support systems in the shipping industry. We propose a linear model with Ballast Tanks for generating master plans, the first phase of a 2-phase stowage optimization approach, that includes the main stability and stress moments calculations. Our approach linearizes the center of gravity calculation and hydrostatic data tables of the vessel in order to formulate stability and stress moments constraints that can handle variable displacement. The accuracy level of these linearizations is evaluated when the displacement of the vessel is allowed to change within a small band.
Kris De Baere - One of the best experts on this subject based on the ideXlab platform.
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Assessment of corrosion resistance, material properties, and weldability of alloyed steel for Ballast Tanks
Journal of Marine Science and Technology, 2017Co-Authors: Kris De Baere, Helen Verstraelen, Silvia Lenaerts, Remke Willemen, Jean-pierre Smet, Jérôme Tchoufang Tchuindjang, Jacqueline Lecomte-beckers, Raf Meskens, Hwan Gyo Jung, Geert PottersAbstract:Ballast Tanks are of great importance in the lifetime of modern merchant ships. Making a Ballast tank less susceptible to corrosion can, therefore, prolong the useful life of a ship and, thereby, lower its operational cost. An option to reinforce a Ballast tank is to construct it out of a corrosion-resistant steel type. Such steel was recently produced by POSCO Ltd., South Korea. After 6 months of permanent immersion, the average corrosion rate of A and AH steel (31 samples) was 535 g m^−2 year^−1, while the Korean CRS was corroding with 378 g m^−2 year^−1. This entails a gain of 29 %. Follow-up measurements after 10, 20, and 24 months confirmed this. The results after 6 months exposure to alternating wet/dry conditions are even more explicit. Furthermore, the physical and metallurgical properties of this steel show a density of 7.646 t/m^3, the elasticity modulus 209.3 GPa, the tensile strength 572 MPa, and the hardness 169HV10. Microscopically, the metal consists of equiaxed and recrystallized grains (ferrite and pearlite), with an average size of between 20 and 30 µm (ASTM E 112—12 grain size number between 7 and 8) with a few elongated pearlitic grains. The structure is banded ferrite/pearlite. On the basis of a series of energy dispersive X-ray spectrometer measurements the lower corrosion rate of the steel can be attributed to the interplay of Al, Cr, their oxides, and the corroding steel. In addition, the role of each element in the formation of oxide layers and the mechanisms contributing to the corrosion resistance are discussed.
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A field study of the effectiveness of sacrificial anodes in Ballast Tanks of merchant ships
Journal of Marine Science and Technology, 2014Co-Authors: Kris De Baere, Helen Verstraelen, Raf Dewil, Silvia Lenaerts, Lucien Lemmens, Yves Ingelgem, Geert PottersAbstract:Sacrificial anodes have become a standard practice for the protection of Ballast Tanks of merchant vessels against corrosive damage. A well protected tank should extend the life span of a ship and consequently enhances its economic value. An in situ survey comprising more than 100 merchant vessels provided the opportunity to measure the impact of these anodes on the life expectancy of these vessels. Contrary to the general belief of these anodes’ beneficial effect, no significant difference was found in our observations in terms of corrosion occurrence between ship populations with and without sacrificial anodes, across all ship ages. This may be explained by the highly variable conditions and the complex geometry in a Ballast tank severely impede optimal and straightforward installation of these anodes in these Tanks. Also, poorly placed anodes in it may harm the integrity of the coating of the tank. We therefore plead for uniform and clear rules on anode installation and inspection.
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Impact of tank construction on corrosion of ship Ballast Tanks
Materials Performance, 2010Co-Authors: Kris De Baere, Helen Verstraelen, Raf Dewil, L. F. Lemmens, Silvia Lenaerts, Tharcisse Nkunzimana, Geert PottersAbstract:Many elements influence corrosion in Ballast Tanks on merchant vessels. Ballast Tanks on more than 100 vessels were inspected and corrosion rates were evaluated following a standard procedure. Statistical interpretation of the data led to conclusions on the influence of elements such as ship length, sailing area, type of coating, type of vessel, and country of construction.
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In Situ Study of Ballast Tank Corrosion on Ships-Part 2
Materials Performance, 2009Co-Authors: Helen Verstraelen, Kris De Baere, Raf Dewil, L. F. Lemmens, Silvia Lenaerts, Willy Schillemans, Geert PottersAbstract:A study was undertaken to determine causes and effects of corrosion processes in Ballast Tanks. Part 1 of this article (October 2009 MP) described the data collection. Part 2 describes the development of a corrosion index (CI) derived from the general International Association of Classification Societies corrosion assessment methods. The CI can be used in situ to assess Ballast tank corrosion. An average timeline for corrosion of Tanks is presented.
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In situ study of Ballast tank corrosion on ships. Part 1
Materials Performance, 2009Co-Authors: Helen Verstraelen, Kris De Baere, Raf Dewil, L. F. Lemmens, Silvia Lenaerts, Willy Schillemans, Geert PottersAbstract:A study was undertaken to determine causes and effects of corrosion processes in Ballast Tanks. Part 1 of this article describes the data collection and Part 2 (November 2009 MP) explains the development of a refined corrosion index to determine an average tirneline for corrosion of Tanks.
Harshana Rajakaruna - One of the best experts on this subject based on the ideXlab platform.
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Improving estimation of phytoplankton abundance and distribution in Ballast water discharges
Journal of Applied Phycology, 2020Co-Authors: Oscar Casas-monroy, Harshana Rajakaruna, Sarah A. BaileyAbstract:With the International Maritime Organization’s (IMO) International Convention for the Control and Management of Ships’ Ballast Water and Sediments now in force, determining abundance and distribution of phytoplankton inside Ballast Tanks is critical for successful Ballast water management, particularly when assessing compliance. The relationship between the abundance and distribution of cells was examined to obtain the best representative sample of the entire phytoplankton community in Ballast Tanks, comparing three Ballast water sampling techniques including in-line, in-tank, and Van Dorn bottle methods. Lloyd’s index, D_ y , and Gini index were applied to compare methods of sample collection and determine representativeness of samples and performance of sampling methods. Phytoplankton abundance trends from live microscopy counts using fluorescein diacetate (FDA) were also compared to those using a FlowCAM on preserved samples. The phytoplankton community showed a patchy distribution inside the Ballast tank and this trend was observed across all voyages. The estimated marginal mean analysis showed that in hypothetical conditions (e.g., 702 m^3 of water in Ballast tank and phytoplankton whole-tank abundance of 19,522 cells), the difference among the three methods was small. Conversely, statistical analysis performed on empiric abundances using a negative binomial regression model determined that the volume discharged during sampling of Ballast water has an effect on the number of cells collected on a given voyage. Results of this study also confirmed that the in-line method may be a better method at collecting phytoplankton samples from Ballast Tanks than the in-tank or Van Dorn method, regardless of the time at which samples are collected. Finally, the number of living cells and the number of preserved cells showed similar trends for most of the voyages, despite fewer samples analyzed using FDA.
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Optimizing methods to estimate zooplankton concentration based on generalized patterns of patchiness inside Ballast Tanks and Ballast water discharges.
Ecology and evolution, 2017Co-Authors: Sarah A. Bailey, Harshana RajakarunaAbstract:Zooplankton populations are spatially heterogeneous in nature and inside ship Ballast Tanks. Sampling methods should take heterogeneity into account, particularly when estimating quantitative variables such as abundance or concentration. It is particularly important to generate unbiased estimates of zooplankton concentration in Ballast water when assessing compliance with new international Ballast water discharge standards. We measured spatial heterogeneity of zooplankton within Ballast water using three sampling methodologies. In-tank pump samples were collected at fixed depths within the vertical part of the Ballast tank (side tank). Vertical net-haul samples were collected from the upper portion of the tank as a depth-integrated and historically relevant method. In-line, time-integrated samples were collected during Ballast discharge by an isokinetic sample probe, likely representing the double bottom part of the Ballast tank. The bias and precision associated with each sampling method were evaluated in reference to the estimated average abundance of the entire Ballast tank, which was modeled from the data collected by all methods. In-tank pump samples provided robust evidence for vertical stratification of zooplankton concentration in the side tank. A consistent trend was also observed for in-line discharge samples, with zooplankton concentration decreasing through time as the Ballast tank is being discharged. Sample representativeness, as compared to the tank average, varied depending on the depth or tank volume discharged. In-line discharge samples provided the least biased and most precise estimate of average tank abundance (having lowest mean squared error) when collected during the time frame of 20%-60% of the tank volume being discharged. Results were consistent across five trips despite differences in Ballast water source, season, and age.
