| 1. |
- Davis, R. A., et al.
(författare)
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Evaluation of natural resveratrol multimers as marine antifoulants
- 2023
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Ingår i: Biofouling. - : Taylor and Francis Ltd.. - 0892-7014 .- 1029-2454. ; 39:8, s. 775-784
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Tidskriftsartikel (refereegranskat)abstract
- In the current study we investigate the antifouling potential of three polyphenolic resveratrol multimers (-)-hopeaphenol, vaticanol B and vatalbinoside A, isolated from two species of Anisoptera found in the Papua New Guinean rainforest. The compounds were evaluated against the growth and settlement of eight marine microfoulers and against the settlement and metamorphosis of Amphibalanus improvisus barnacle cyprids. The two isomeric compounds (-)-hopeaphenol and vaticanol B displayed a high inhibitory potential against the cyprid larvae metamorphosis at 2.8 and 1.1 mu M. (-)-Hopeaphenol was also shown to be a strong inhibitor of both microalgal and bacterial adhesion at submicromolar concentrations with low toxicity. Resveratrol displayed a lower antifouling activity compared to the multimers and had higher off target toxicity against MCR-5 fibroblasts. This study illustrates the potential of natural products as a valuable source for the discovery of novel antifouling leads with low toxicity.
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| 2. |
- Oliveira, Dinis, 1991, et al.
(författare)
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Ship hull in-water cleaning and its effects on fouling-control coatings
- 2020
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Ingår i: Biofouling. - : Informa UK Limited. - 0892-7014 .- 1029-2454. ; 36:3, s. 332-350
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Tidskriftsartikel (refereegranskat)abstract
- Today, ship hull fouling is managed through fouling-control coatings, complemented with inwater cleaning. During cleaning, coating damage and wear must be avoided, for maximum coating lifetime and reduced antifoulant release. When possible, cleaning should target early stages of fouling, using minimal forces. However, such forces, and their effects on coatings, have not yet been fully quantified. In this one-year study, minimal cleaning forces were determined using a newly-designed immersed waterjet. The results show that bi-monthly/monthly cleaning, with maximum wall shear stress up to 1.3 kPa and jet stagnation pressure 0.17 MPa, did not appear to cause damage or wear on either the biocidal antifouling (AF) or the biocide-free foul-release (FR) coatings. The AF coating required bi-monthly cleanings to keep fouling to incipient slime (time-averaged results), while the FR coating had a similar fouling level even without cleaning. The reported forces may be used in matching cleaning parameters to the adhesion strength of the early stages of fouling.
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| 3. |
- Vinagre, Pedro, et al.
(författare)
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Probing the correlation between corrosion resistance and biofouling of thermally sprayed metallic substrata in the field
- 2022
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Ingår i: Biofouling (Print). - : Taylor and Francis Ltd.. - 0892-7014 .- 1029-2454. ; 38:2, s. 147-161
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Tidskriftsartikel (refereegranskat)abstract
- The correlation between inherent corrosion resistance and biofouling was investigated for five different metallic coatings. Steel panels thermally spray-coated with either aluminium, Monel, bronze or different aluminium alloys were tested in controlled salt mist conditions and electrochemical corrosion tests and subsequently employed at sea. The biofouling of the panels was monitored at different depths (5, 10 and 15 m) at periods ranging from 5 to 12 months. The main macrofouling organisms were quantified and analysed using permutational multivariate analysis. The results indicate a significant difference in fouling pressure between depths and the geographic sites used. No statistically significant link between high corrosion resistance and lower biofouling pressure was observed, indicating that the main marine macrofoulers settled equally well on corrosion resistant and corrosion prone metallic surfaces. This work sheds light on biofouling of thermally sprayed metallic substrata and it characterizes and compares biofouling assemblages from different biogeographical regions in Europe.
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| 4. |
- Yeginbayeva, Irma, 1986, et al.
(författare)
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Effects of ‘in-service’ conditions–mimicked hull roughness ranges and biofilms–on the surface and the hydrodynamic characteristics of foul-release type coatings
- 2020
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Ingår i: Biofouling. - : Informa UK Limited. - 0892-7014 .- 1029-2454. ; 36:9, s. 1074-1089
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Tidskriftsartikel (refereegranskat)abstract
- To develop a better understanding of ‘in-service’ performance of modern marine coatings, this study explored the combined effects of different roughness ranges of foul-release coating (FRC) and light biofouling (slime) on the surface, boundary layer and drag characteristics under a range of ‘in-service’ conditions. Natural and laboratory biofilms were grown dynamically on FRC panels by exposing panels in facilities dedicated to realistic fouling culture. The boundary layer experiments were conducted in a circulating water tunnel. Boundary layer similarity-law scaling was used to predict the combined effects of coating roughness and biofilms on the added frictional resistance (% (Formula presented.) and added required effective power (Formula presented.)) for a benchmark KRISO container ship (KCS) and a bulk carrier. The increase in (Formula presented.) due to the presence of biofilms on commercial FRC is estimated to be between 7% and 16% depending on the biofilm type, biofilm thickness and percentage coverage. Significant increases in effective power are estimated for non-fouling control primers with heavy fouling. Moreover, the paper suggests updated roughness allowances ((Formula presented.)) for two vessel types assuming FRCs on their hulls with more representative hull roughness ranges and fluffy biofilms.
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