4 documents found, page 1 of 1
Corrosion Behavior of Austenitic Stainless Steels in CO2-Saturated Synthetic Oi...
Cardoso,Jorge Luiz; Mandel,Marcel; Krüger,Lutz; Herculano,Luís Flávio Gaspar; Lima Neto,Pedro de; Silva,Marcelo José Gomes daThe corrosion behavior of austenitic and superaustenitic stainless steels was investigated in carbon dioxide-saturated synthetic oil field formation water using cyclic polarization tests. In order to measure the effect of carbon dioxide pressure, the samples were also exposed in a pressurized medium containing carbon dioxide and synthetic air. For this purpose, tests were performed for long exposure time at 80 ...
New Alkaloids from Margaritopsis carrascoana (Rubiaceae)
Nascimento,Raimundo R. G.; Pimenta,Antônia T. A.; Lima Neto,Pedro de; C. Junior,José R.; Costa-Lotufo,Letícia V.; Ferreira,Elthon G.Two new alkaloids containing Nb-methyl-triptamine units linked to bis-quinoline moieties, N-8”-formyl-calycosidine and N-8”-methyl-N-1’-demethyl-iso-calycosidine, were isolated from the aerial part of Margaritopsis carrascoana, along with known calycosidine and hodgkinsine. The cytotoxicity of the isolated alkaloids has been evaluated against cancer cell lines. The first two compounds showed only weak activity ...
5-(4-pyridinyl)-1,3,4-oxadiazole-2-thiol on gold: SAM Formation and electroacti...
Paulo,Tercio de F.; Silva,Maria A. S. da; Pinheiro,Solange de O.; Meyer,Emerson; Pinheiro,Lucidalva S.; Freire,José A.; Tanaka,Auro A.5-(4-pyridinyl)-1,3,4-oxadiazole-2-thiol (Hpyt) spontaneously adsorbs on gold forming SAMs (self-assembled monolayers) that, based on STM (Scanning Tunneling Microscopy) and electrochemical data, contain pinholes through which [Fe(CN)6]4- and [Ru(NH3)6]3+ probe molecules access the underlying gold electrode. For the former molecule, the dependence of the faradaic current on the electrolyte solution pH value all...
Deformation induced martensite in an AISI 301LN stainless steel: characterizati...
Abreu,Hamilton Ferreira Gomes de; Carvalho,Sheyla Santana de; Lima Neto,Pedro de; Santos,Ricardo Pires dos; Freire,Válder NogueiraIn austenitic stainless steels, plastic deformation can induce martensite formation. The induced martensite is related to the austenite (gamma) instability at temperatures close or below room temperature. The metastability of austenite stainless steels increases with the decreasing of stacking fault energy (SFE). In this work, the deformation induced martensite was analyzed by X ray diffraction, electron back s...