Encontrados 43 documentos, a visualizar página 1 de 5
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...
The cation effect on the aqueous solubility of amino acids in the presence of s...
Tomé, L.I.N.; Pinho, Simão; Jorge, M.; Gomes, J.R.B.; Coutinho, J.A.P.Aiming at contributing to the understanding the molecular level mechanisms governing the behavior of biocompounds in aqueous saline environments, experimental solubility measurements and molecular dynamics (MD) simulations were performed for aqueous solutions of three amino acids (alanine, valine and isoleucine) in the presence of a series of inorganic salts.
Tribological evaluation of hydrogels for artificial articular cartilage
Lopes, J. L.; Machado, J. M.; Castanheira, L.; Granja, P. L.; Gama, F. M.; Dourado, Fernando; Gomes, J. R.Bacterial cellulose (BC) is a natural and biocompatible gel with unique properties, such as high water holding capacity, ultra-fine fibre network and high strength that make it an interesting material for biotribological purposes. In this work, unmodified BC pellicles were grown from Gluconacetobacter xylinus in order to be used as tribological samples against bovine articular cartilage (BAC) in the presence of...
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...
Experimental and molecular dynamics simulation studies on thee solubilityof ami...
Tomé, L.I.N.; Pinho, Simão; Jorge, M.; Gomes, J.R.B.; Coutinho, J.A.P.Separation and concentration of biological compounds are current subjects of interest due to their high cost in comparison to the total manufacture cost. For that purpose electrolytes may be employed as they can effect significantly biochemicals solubilities, a feature that has been used for salt-induced precipitation of proteins.
The cation effect on the aqueous solubility of amino acids in the presence of s...
Tomé, L.I.N.; Pinho, Simão; Jorge, M.; Gomes, J.R.B.; Coutinho, J.A.P.The study of the solubility behavior of amino acids and proteins in aqueous electrolyte solutions is of utmost importance to understand the biochemistry of natural systems, develop medical and pharmaceutical responses to diseases induced by biochemical disorders and improve the efficiency of biotechnological processes. Although the effect of common salts on the aqueous solubility of amino acids and proteins is ...
Friction and wear behaviour of bacterial cellulose against articular cartilage
Lopes, J. L.; Machado, J. M.; Castanheira, L.; Granja, P. L.; Gama, F. M.; Dourado, Fernando; Gomes, J. R.Bacterial cellulose (BC) is a natural and biocompatible material with unique properties, such as high water holding capacity, ultra-fine fibre network and high strength that makes it an attractive material for the repair of articular cartilage lesions. However, data on the tribological properties of BC is very scarce, particularly if natural articular cartilage is involved in the contact. In this work, unmodifi...
Tribological behaviour of multilayered textile composites : the effect of recip...
Mathew, M. T.; Padaki, N. V.; Alagirusamy, R.; Deopura, B. L.; Fangueiro, Raúl; Rocha, L. A.; Gomes, J. R.Textile composites have been used for various applications because of their enhanced strength/weight ratio and versatile properties compared to other materials such asmetals. Many studies have investigated the tribological behaviour of textilecomposites, but none have focused onthe tribological characterization of 3D multilayeredwoven reinforced textile composites. Five types of 3-plywoven interlocked structure...
Influência da incorporação de partículas de SiC na microestrutura e no comporta...
Vieira, A. C.; Rocha, L. A.; Gomes, J. R.Devido à boa relação entre densidade e resistência mecânica apresentada pelos compósitos de matriz de alumínio, estes materiais têm-se destacado em algumas aplicações industriais. Com efeito, a adição de reforços cerâmicos às ligas de alumínio, nomeadamente partículas de SiC, resulta na melhoria das suas propriedades mecânicas com particular impacto no aumento da resistência ao desgaste, ampliando o seu campo d...
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