CoaST Maritime Test Centre : an investigation of biofouling propensity / Morten L. Pedersen in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 20, N° 3 (05/2023)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 20, N° 3 (05/2023) . - p. 857-868 Titre : CoaST Maritime Test Centre : an investigation of biofouling propensity Type de document : texte imprimé Auteurs : Morten L. Pedersen, Auteur ; Burak Ulusoy, Auteur ; Claus Erik Weinell, Auteur ; Frederikke B. Zilstorff, Auteur ; Songgeng Li, Auteur ; Kim Dam-Johansen, Auteur Année de publication : 2023 Article en page(s) : p. 857-868 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Encrassement Essais (technologie) Evaluation Revêtements -- Détérioration Salissures biologiques Test d'immersion Index. décimale : 667.9 Revêtements et enduits Résumé : The performance of fouling control coatings (FCC) is evaluated based on static exposure on test sites worldwide. There are different standards concerning the evaluation of the performance of the FCC. However, to the knowledge of the authors, there is not a standardized reporting guideline for how to evaluate the test site in which the FCC is exposed. Several factors such as water conditions, seasonal biofouling, and accessibility of sunlight can vary dependent on placement within or between test sites. This in turn makes it difficult to compare the performance of FCC exposed at different locations within a or at another test site. In this study, an analysis of the CoaST Maritime Test Centre (CMTC) has been performed to investigate how geographical orientation and changes in depth influence the biofouling propensity on coated panels. The investigation showed no statistical significance in the biofouling propensity between panels exposed to different geographical orientations at the CMTC. Similarly, no statistical significance was found between panels placed at different depths at the CMTC. If similar reporting was performed at other test sites, a better basis for comparison of FCC worldwide would be obtained, and this could be achieved with a standardized reporting guideline. Note de contenu : - METHOD : CoaST Maritime Test Centre - Test panels - Evaluation method - RESULTS AND DISCUSSION : Biofouling environment at the CMTC - The influence of geographical orientation on the biofouling propensity - The influence of depth on the biofouling propensity - Horizontal setup - Standardized reporting for comparability of FCC within and between test sites - Table 1 : The coverage percentage intervals and the related weighted values for the four biofouling categories - Table 2 : Investigation of the influence of geographical orientation on biofouling growth - Table 3 : The significance of the biofouling deviation between the cartridges fourth and fifth row, due to the difference in depth DOI : https://doi.org/10.1007/s11998-022-00707-w En ligne : https://link.springer.com/content/pdf/10.1007/s11998-022-00707-w.pdf?pdf=button% [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39433 [article]

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Intumescent alkali silicate and geopolymer coatings against hydrocarbon fires / Burak Ulusoy in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 20, N° 1 (01/2023)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 20, N° 1 (01/2023) . - p. 233-248 Titre : Intumescent alkali silicate and geopolymer coatings against hydrocarbon fires Type de document : texte imprimé Auteurs : Burak Ulusoy, Auteur ; Aixiao Fu, Auteur ; Hafeez Ahmadi, Auteur ; Kim Dam-Johansen, Auteur ; Hao Wu, Auteur Année de publication : 2023 Article en page(s) : p. 233-248 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Acier L'acier est un alliage métallique utilisé dans les domaines de la construction métallique et de la construction mécanique. L'acier est constitué d'au moins deux éléments, le fer, très majoritaire, et le carbone, dans des proportions comprises entre 0,02 % et 2 % en masse1. C'est essentiellement la teneur en carbone qui confère à l'alliage les propriétés du métal qu'on appelle "acier". Il existe d’autres métaux à base de fer qui ne sont pas des aciers comme les fontes et les ferronickels par exemple. Carbonate de calcium Le carbonate de calcium (CaCO3) est composé d'un ion carbonate (CO32-) et d'un ion calcium (Ca2+), sa masse molaire est de 100,1 g/mole. C'est le composant principal du calcaire et de la craie, mais également du marbre. C'est aussi le principal constituant des coquilles d'animaux marins, du corail et des escargots. Cendres volantes Enrobage (technologie) Essais de comportement au feu Géopolymères Les géopolymères sont la réciproque des polymères organiques. À la place de dérivés du pétrole et de la chaîne carbonée, on utilise de la matière minérale composée de silice et d’alumine. Les géopolymères sont basés sur des alumino-silicates désignés sous le terme poly(sialate), qui est une abréviation de poly(silico-oxo-aluminate) ou (-Si-O-Al-O-)n (soit n le degré de polymérisation). La structure chimique de la Figure 1 montre un géopolymère poly(sialate-siloxo) résultant d'une géosynthèse de poly(silisique) acide (SiO2)n et de potassium alumino-silicate, en milieu alcalin (KOH, NaOH). Dans cette structure, le groupement sialate (Si-O-Al-O-) est un agent de réticulation. On pense que le mécanisme de la synthèse géochimique se fait par l'intermédiaire d'oligomères (dimère, trimère) qui constituent les véritables groupements structuraux unitaires formant une structure macromoléculaire tridimensionnelle. Ignifugeants Composé chimique utilisé pour réduire l'inflammabilité. Il peut être incorporé au produit durant sa fabrication ou appliqué ultérieurement à sa surface. Intumescence (chimie) Kaolin Métaux -- Revêtements protecteurs Silicates alcalins Thermochimie Index. décimale : 667.9 Revêtements et enduits Résumé : This work focuses on the investigation of the fire protection of steel using inorganic intumescent alkali silicate and geopolymer (alkali aluminosilicate) coatings at temperatures relevant for hydrocarbon fires, as described in the UL1709 standard. Pure alkali silicate coatings based on Na, K, or a mixture of these with Li exhibited high initial expansion followed by melting. In comparison, Li-silicate coatings expanded less but demonstrated significantly higher thermal stability. Increasing the SiO2/Na2O molar ratio prolonged the fire protection time, explained by the lower melt formation proposed by global equilibrium calculations. The presence of melting in the high expanding alkali silicate systems limits their use in hydrocarbon fire conditions. In comparison to pure alkali silicates, geopolymer coatings with kaolin, metakaolin, and fly ash and additional CaCO3 displayed a higher thermal stability confirmed by global equilibrium calculations. The kaolin-based coating provided the best fire protection with a critical time of 37.6 min, explained by its high expansion compared to metakaolin and fly ash-based coatings. Examining the influence of CaCO3 and kaolin content suggests that an optimum exists for the kaolin coatings in terms of expansion, fire protection, and thermal stability. The best performing kaolin coating (37.6 min) had a lower fire protection compared to a state-of-the-art commercial organic hydrocarbon coating (44.2 min), caused by their differences in internal structure. The commercial coating expanded to a more compact microporous solid, while the kaolin coating qualitatively displayed a higher proportion of macropores. This in turn suggests that future work must be performed to further improve the internal structure of the kaolin-based coatings to ensure good fire protection. Note de contenu : - EXPERIMENTAL : Materials - Coatings - Furnace hydrocarbon fire (UL1709) tests - Thermodynamic calculations (FactSage) - SEM/EDX - RESULTS AND DISCUSSION : Alkali silicate coatings - Alkali aluminosilicate (geopolymer) coatings - Geopolymer coating versus commercial hydrocarbon coating - Table 1 : Composition of alkali silicate solutions in wt% with SiO2/M2O molar ratios of 3.4 and 4.2, where M = K, Li, and Na. For the mixture, the molar fractions of alkali silicates were Na2O = K2O = 0.37 and Li2O = 0.26 - Table 2 : Composition of geopolymer solutions (molar: 1.2 Na2O-Al2O3–6.5 SiO2-1.3 CaCO3-31 H2O) in wt% with different Al-source - Table 3 : Fitted drying constant mAS∗, describing the steady-state weight of partially dehydrated product. Liquid (H2O) to solid (L/S) weight ratio and dry matter content in the initial mixture calculated from the coating compositions. Estimated solid-bound H2O content in coating determined from the difference between mAS∗ and the dry matter content - Table 4 : Expansion and mass loss data of kaolin, metakaolin, and fly ash coatings measured after exposure - Table 5 : Identification and molecular formula of compositions with varying kaolin content. Note, K22 = base kaolin coating - Table 6 : Expansion and mass loss data of coatings with varying kaolin content measured after exposure - Table 7 : Identification and molecular formula of compositions with varying kaolin content. Ca10 = base kaolin coating - Table 8 : Expansion, mass loss data, and qualitative-evaluated mechanical properties of coatings with varying CaCO3 content measured after exposure DOI : https://doi.org/10.1007/s11998-022-00659-1 En ligne : https://link.springer.com/content/pdf/10.1007/s11998-022-00659-1.pdf?pdf=button Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38839 [article]

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Marine biofouling resistance rating using image analysis / Morten Pedersen in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 19, N° 4 (07/2022)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 19, N° 4 (07/2022) . - p. 1127-1138 Titre : Marine biofouling resistance rating using image analysis Type de document : texte imprimé Auteurs : Morten Pedersen, Auteur ; Claus Erik Weinell, Auteur ; Burak Ulusoy, Auteur ; Kim Dam-Johansen, Auteur Année de publication : 2022 Article en page(s) : p. 1127-1138 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Analyse d'image L'analyse d'image est la reconnaissance des éléments contenus dans l'image. Il ne faut pas confondre analyse (décomposition en éléments) et traitement (action sur les composantes) de l'image. Marines (peinture) Résistance à la salissure Revêtements antisalissures Salissures biologiques Index. décimale : 667.9 Revêtements et enduits Résumé : Biofouling on ship hulls can cause increased fuel consumption and the global spread of nonindigenous species. The shipping industry utilizes fouling control coatings (FCC) to prevent biofouling from occurring on the ship hull. The evaluation standards for the performance of FCC are based on manual inspections, which unavoidably induce some degree of subjectivity. A standardized biofouling recognition model using image analysis would provide a more objective basis for the evaluation of FCC. For this purpose, several coated panels were immersed in the ocean at CoaST Maritime Test Centre for an exposure period of six weeks, whereafter, the panels were fully covered with biofouling. The program ilastik was then successfully used to train a pixel classification model, which could provide a simple segmentation of the different biofouling categories detected on a coated surface. From the simple segmentation, a coverage percentage of biofouling was determined. The percentages can stand alone to provide information on the degree of biofouling or be used in combination with the guidelines from the European Chemicals Agency to calculate a fouling resistance rating (FRR). The FRR obtained from the model was compared with FRR values obtained from the manual evaluation of the panels. Note de contenu : - METHOD : Exposure procedure - Fouling resistance rating (FRR) - Image analysis procedure - RESULTS : Deviation in manual evaluations - Pixel classification model - Comparison of manual and model FRR - DISCUSSION : Challenges related to panel imaging - Pixel classification model - Time efficiency - ECHA guideline - Future work - Table 1 : The weighted ratings, used to determine the FRR, for the different categories of biofouling related to the coverage intervals. A modification of the tables from ECHA - Table 2 : Summary of the FRR for all the panels achieved from the model and the manual evaluation. The ratings in the brackets show the manual evaluation DOI : https://doi.org/10.1007/s11998-021-00612-2 En ligne : https://link.springer.com/content/pdf/10.1007/s11998-022-00612-2.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38041 [article]

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