Estudo de filmes finos de TixOy depositados em aço-carbono para aplicação antincrustante

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Programa de Pós-Graduação em Engenharia e Ciências Mecânicas, Joinville, 2016.Os processos de bioincrustação marinha são frequentemente observados em diversos materiais utilizados pela indústria naval e oceânica. Atualmente, há um grande esforço no desenvolvimento de pesquisas científicas que conduzam a soluções para este problema, com mínima agressão ambiental ao ambiente marinho. Entre os materiais já desenvolvidos para esta finalidade, podem ser citadas as tintas à base de TBT (tributilestanho), que tem grande eficiência, porém são muito tóxicas. O dióxido de titânio (TiO2) pode ser uma alternativa, devido ao desempenho antimicrobiano e atóxico. Considerando a relevância do problema a nível global e ausência de uma solução ecologicamente correta, foi realizada avaliação do potencial antincrustante de filmes finos de TixOy depositados por Triodo Magnetron Sputtering Reativo em amostras de aço-carbono. Após as deposições as amostras foram colocadas em ambiente marinho natural, na marina Cubatão e monitoradas para o estudo do processo antincrustante. O estudo sistemático revelou a formação de filmes finos de TiO2 cristalinos para teores de 39% e 62% de O2 e 100% para amorfo. As estruturas cristalinas caracterizam-se pela presença das fases anatase e rutile. Desenvolveu uma metodologia de estudo experimental para avaliação da exposição ao ambiente marinho, caracterização dos filmes finos e da bioincrustação. Mesmo não sendo possível visualizar a bioincrustação, a análise da quantidade de estruturas aderidas permite uma conclusão indireta a respeito do potencial antincrustante, já que a possibilidade de crescimento de seres vivos está diretamente relacionada com a facilidade de adesão à superfície. Neste sentido, as amostras com TiO2 cristalino apresentaram evidente menor proporção de estruturas aderidas em comparação com a amostra amorfa.Abstract : Marine biofouling processes are frequently observe in various materials used by the naval and oceanic industries. Currently, there is a great effort in the development of scientific researches that lead to solutions to this problem, with minimal environmental aggression to the marine environment. Among the materials already developed for this purpose, can be cited TBT (tributyltin) based paints, which have great efficiency, but are very toxic. Titanium dioxide (TiO2) may be an alternative, due to antimicrobial and non-toxic performance. Considering the relevance of the problem at global level and the absence of an ecologically correct solution, an evaluation was made of the antifouling potential of TixOy thin films deposited by Reactive Magnetron Sputtering Triodo in carbon steel samples. After deposition the samples were placed in a natural marine environment at the Cubatão marina and monitored for the study of the antifouling process. The systematic study revealed the formation of thin films of crystalline TiO2 for contents of 39% and 62% of O2 and 100% for amorphous. The crystalline structures are characterized by the presence of the anatase and rutile phases. It were developed an experimental study methodology to evaluate exposure to the marine environment, characterization of thin films and biofouling. Although it is not possible to visualize the biofouling, the analysis of the amount of adhered structures allows an indirect conclusion regarding the antifouling potential, since the possibility of growth of living beings is directly related to the ease of adhesion to the surface. In this sense, samples with crystalline TiO2 showed an evident lower proportion of adhered structures in comparison with the amorphous sampl

TiO2 thin Films for Biofouling Applications

<div><p>This work presents a study of TiO2 thin films prepared by sputtering, for using as protection for biofouling action on marine structures. Titanium oxide thin films were prepared with different amount of oxygen on the surface of regular 1020 steel, a structural material for marine technology. The cristalline structure analysis evidenced the formation of anatase and rutile phases, as well as an amorphous phase of titanium oxide. Roughness measurements shown that the surface finish can contribute to the fixation of microorganisms. The crystalline TiO2 thin films was evaluated as a potential biofouling protective coating. Contact angle measurements revealed that under UV-C light, the material evidenced a changing in wettability from hydrophobic to hydrophilic behavior, what is associated to the activation of photocatalytic reactions that is nocive for living beings on its surface. The effect of marine ambient on sample corroborates this conclusion, where after 6 months of exposure it was not sufficient for growing of biofouling on surface.</p></div

Neotropical freshwater fisheries : A dataset of occurrence and abundance of freshwater fishes in the Neotropics

The Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large-scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications