Encontrados 23 documentos, a visualizar página 1 de 3
Self-mated tribological systems based on multilayer micro/nanocrystalline CVD d...
Salgueiredo, E.; Abreu, C. S.; Amaral, M.; Oliveira, F. J.; Gomes, J. R.; Silva, R. F.The tribological response of multilayer micro/nanocrystalline diamond coatings grown by the hot filament CVD technique is investigated. These multigrade systems were tailored to comprise a starting microcrystalline diamond (MCD) layer with high adhesion to a silicon nitride (Si3N4) ceramic substrate, and a top nanocrystalline diamond (NCD) layer with reduced surface roughness. Tribological tests were carried ou...
Properties of tantalum oxynitride thin films produced by magnetron sputtering: ...
Cristea, D.; Constantin, D.; Crisan, A.; Abreu, C. S.; Gomes, J. R.; Barradas, N. P.; Alves, E.; Moura, C.; Vaz, F.; Cunha, L.The main purpose of this work is to present and to interpret the change of structure and physical properties of tantalum oxynitride (TaNxOy) thin films, produced by dc reactive magnetron sputtering, by varying the processing parameters. A set of TaNxOy films was prepared by varying the reactive gases flow rate, using a N2/O2 gas mixture with a concentration ratio of 17:3. The different films, obtained by this p...
A DLC/diamond bilayer approach for reducing the initial friction towards a high...
Amaral, M.; Carreira, D. J; Fernandes, A. J. S.; Abreu, C. S.; Oliveira, F. J.; Gomes, J. R.; Silva, R. F.Sliding contact mechanics is used to account for the net increase of the bearing capacity of high wear-resistant CVD diamond coatings when an outer layer of a DLC lubricant film is deposited on their top surface. Experimental results,namely the critical failure load, taken from reciprocating ball-on-plate tribological testing of such DLC/diamond bilayers, are on the basis of this statement. DC magnetron sputter...
Inclusões intracitoplasmáticas hialinas na medular da adrenal de bovinos
Mesquita,L.P; Abreu,C.C; Wouters,F; Varaschin,M.S; Bezerra Jr,P.SCytoplasmic inclusion bodies in adrenal medullary chromaffin cells have been described in various species including humans. These inclusions are believed to be related to certain infectious, toxic and neurodegenerative diseases. No reports concerning such adrenal inclusions have been described in bovines. Adrenal glands from twenty bovines were evaluated in a retrospective study. Seven of these exhibited inclus...
As Implicações/Impacto dos Registos de Enfermagem em Linguagem CIPE
Abreu, C; Almeida, MC; Costa, M; Santos, R; Jácome, PA implementação dos registos electrónicos na prática de enfermagem permitirá um vasto suporte na informação, possibilitando o desenvolvimento de formação/investigação, continuidade e monitorização da qualidade dos cuidados. Irá igualmente contribuir para dar maior visibilidade ao impacto dos cuidados de enfermagem nos ganhos em saúde das populações.
Utilização de argilas esmectíticas do nordeste do Brasil para preparação de um ...
Cavalcanti,J. V. F. L; da Motta,M.; Abreu,C. A. M; Baraúna,O. S; Portela,L. A. PO principal objetivo foi a preparação e a utilização de uma argila organofílica com capacidade de promover a separação do composto fenol, encontrado em larga escala nos efluentes aquosos de indústrias petroquímicas. O trabalho consistiu no preparo de um material adsorvente, partindo de cinco tipos diferentes argilas retiradas de bacias localizadas na região nordeste do Brasil: Verde Lodo, Bofe e Chocolate, reti...
Atividade das glicosidases na presença de chá verde e de chá preto
Pereira,L.L.S.; Souza,S.P.; Silva,M.C; Carvalho,G.A.; Santos,C.D.; Corrêa,A.D.; Abreu,C.M.P.Várias plantas têm sido consideradas produtos terapêuticos, dentre elas destacam-se os chás verde e preto, popularmente utilizados para controle da hiperglicemia e obesidade. Objetivou-se neste trabalho avaliar o potencial inibitório sobre as enzimas α-amilase, α e β-glicosidases e o teor de compostos fenólicos do chá verde e do chá preto. O teor de compostos fenólicos encontrados foram de 80,8 ±...
Tribological testing of self-mated nanocrystalline diamond coatings on Si3N 4 c...
Abreu, C. S.; Amaral, M.; Oliveira, F. J.; Tallaire, A.; Bénédic, F.; Syll, O.; Cicala, G.; Gomes, J. R.; Silva, R. F.Due to their much lower surface roughness compared to that of microcrystalline diamond, nanocrystalline diamond (NCD) films are promising candidates for tribological applications in particular when deposited on hard ceramic materials such as silicon nitride (Si3N4). In the present work, microwave plasma assisted chemical vapour deposition of NCD is achieved using Ar/H2/CH4 gas mixtures on plates and ball-shaped...
In-situ friction monitoring of self-mated CVD diamond coatings using acoustic e...
Abreu, C. S.; Oliveira, F. J.; Gomes, J. R.; Belmonte, M.; Fernandes, A. J. S.; Silva, R. F.In-situ measurements of acoustic emission (AE) in self-mated tribological pairs of CVD diamond coated silicon nitride (Si3N4) were made with the purpose of investigating the relationship between AE signal and friction events. A good correlation is found between the energy dissipation/emission processes, therefore enabling the possibility of monitoring the different friction regimes occurring during the sliding ...
CVD diamond coated silicon nitride self-mated systems : tribological behaviour ...
Abreu, C. S.; Oliveira, F. J.; Belmonte, M.; Fernandes, A. J. S.; Gomes, J. R.; Silva, R. F.Friction and wear behaviour of self-mated chemical vapour deposited (CVD) diamond films coating silicon nitride ceramics (Si3N4) were investigated in ambient atmosphere. The tribological tests were conducted in a reciprocal motion ball-on-flat type tribometer under applied normal loads up to 80 N (~10 GPa). Several characterisation techniques - including scanning electron microscopy (SEM), atomic force microscopy...
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