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The deposition of DLC films on 321H stainless steel aims at attributing properties such as high wear resistance and low friction coefficient to the substrate material. Nitrogen added to DLC can improve the film adhesion to metal substrates, but the investigation of its effect on corrosion resistance, an important property for stainless steels, is lacking. The DLC film was deposited by plasma-enhanced chemical vapor deposition (PECVD) using a pulsed-DC power supply with a gas mixture of Ar and CH4, and to the DLC(N) film deposition was used CH4 and N2 varying the percentage of nitrogen from 10 to 50% in the treatment. DLC films improved both the wear and corrosion resistance of 321H stainless steel. The results show that the 10, 20 and 30% of N2 supply during the deposition increased the adhesion of the film on the substrate, enhancing the wear resistance of the treated material. The addition of 40 and 50% of N2 during the deposition, however, impaired the corrosion resistance compared with the substrate. An improvement of adhesion, wear and corrosion resistance were observed for 30% N2 condition. Thus, the incorporation of suitable concentration of nitrogen modifies the features of the DLC film, obtaining a good combination of high wear resistance and corrosion protection due to a combination of structure, high thickness, and high adhesion of the film to 321H stainless steel.

Simultaneamente, em uma mesma época dos anos 1800, duas políticas ligadas à exploração da terra, deram início ao processo de formação da agricultura, nas regiões montanhosas do estado do Rio de Janeiro. Com objetivo de contextualizar historicamente o desenvolvimento da agricultura fluminense e avaliar o seu desempenho produtivo, foram realizadas uma pesquisa na literatura e uma análise de dados quantitativos da atual produção agrícola. Verificou-se que o desenvolvimento desta atividade foi gerado dentro de uma diversidade de ambientes, pessoas, espécies vegetais, estratégias, políticas e situações econômicas que contribuiu para moldar a sua conformação atual, com características, dinâmica agrária e desempenho, diferenciados. Foi identificado que as regiões serrana e sul, apresentaram os maiores faturamentos por hectare e, também, os municípios com maior diversidade produtiva. Made available in DSpace on 2021-04-29T12:31:14Z (GMT). No. of bitstreams: 1 Historico-atualidades-e-desempenho-produtivo-da-agricultura-fluminense.pdf: 734430 bytes, checksum: 70547d91f0bf9a8911dd7e0c9ee76e9a (MD5) Previous issue date: 2021

Dextran is a polysaccharide produced by bacteria of the genus Leuconostoc spp, which causes loss of sucrose and raises sugar and alcohol manufacturing costs, as well as reducing its quality. Therefore, it is important to control the proliferation of this bacterium, both in the sugarcane field and in agroindustry. In the field should be observed, the length of stay between cutting and transport to industry, the presence of impurities, among other factors. In industry, long storage periods should be avoided, as well as taking care of cleaning and asepsis of the mills and broth treatment tanks. The objective of this work is to record dextran content using blockchain technology because it is a distributed database suitable for applications such as this, which will track the dextran content from the sugarcane field to the production of sugar and alcohol in the industry. A blockchain database is very secure against tampering, which is another advantage of this solution. Made available in DSpace on 2020-10-16T09:14:28Z (GMT). No. of bitstreams: 1 AP-Prototype-Dextran-2020.pdf: 486770 bytes, checksum: 03187e65829028820a1cb1e2e3f7f01c (MD5) Previous issue date: 2020 Na publicação: Fabio Cezar da Silva.