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Electrodeposition of Zn-Mn alloys from recycling battery leach solutions in the...
Brito, P. S. D.; Patrício, S.; Rodrigues, L. F.; Santos, D. M. F.; Sequeira, C. A. C.The recovery of metal ions by electrodeposition from solutions resulting from the lixiviation of spent Zn-MnO2 batteries was studied. It was attempted to optimise the electrodeposition process, the selectivity of ion-separation, the morphologic characteristics, and the anticorrosive and galvanic properties of metallic deposits. The simultaneous deposition of zinc and manganese on different ferrous substrates un...
Electrochemical routes for industrial synthesis
Sequeira,C. A. C.; Santos,D. M. F.This review examines the reasons for increasing interest towards electrolyses by the chemical industry, reviews the electrochemical industries as most of them now exist, and provides a status report on the key technological advances which are occurring to meet present and future needs. Classical industries like those of chloroalkali, aluminium, p-aminophenol, adiponitrile, ethylene glycol, anthraquinone, perflu...
Hall Effect measurements on p-n-p InP structures
Sequeira,C. A. C.; Santos,D. M. F.The electrical properties of p-type layers of indium phosphide (InP), formed by the diffusion of zinc into n-type material, are studied by Hall Effect measurements. A wide range of diffusion conditions are used and both homogeneously doped specimens and those containing a zinc atom concentration gradient are produced. A non-correspondence of atom and carrier concentrations is indicated, confirming previous four...
Electrochemical characterization of poly(ethylene oxide)- zinc chloride system ...
Plancha, Maria João; Rangel, C. M.; Sequeira, C.A.C.The system PEOnZnCl2 with n=4-16 was studied in view of its potential application in a solid state rechargeable zinc battery. A.c. conductivity and cationic transference number measurements, in the temperature range 20-150ºC, were performed and the electrochemical stability window was established for the polymer electrolyte with n=4 composition. The ionic conductivity, σ, of this film, follows a VTF behaviour, ...
Prediction of apparent digestibility of hays from natural pastures of the North...
Galvão, Lurdes; Guedes, C.M.; Rodrigues, M.A.M.; Silva, S.R.; Valentim, Ramiro; Moreira, Olga; Ribeiro, José Ramalho; Sequeira, C.A.In the Northeast region of Portugal hays from natural pastures are traditionally used as the main feed during the period of drought and the evaluation of its nutritive value is essential. The aim of this study was to predict the apparent organic matter digestibility (OMD) of 21 hays from natural pastures based on chemical composition, pepsin-cellulase solubility of organic matter (OMS) and in vitro organic matt...
Four-point probe electrical measurements on p-n-p InP structures
Sequeira,C. A. C.; Santos,D. M. F.The diffusion of zinc into n-type InP has been studied by four-point probe electrical measurements on homogeneously doped crystals at 750 ºC. The zinc carrier concentration in the diffused layer was approximately 3 x 10(18) cm-3 and its mobility was assumed to be about 40 cm² V-1 s-1. It was observed that the concentration of free carriers throughout the entire diffused region is always less than the number of ...
Fluorescence in nanostructured fulleride films
Lobo, R. F. M.; Costa, M. S.; Ribeiro, J. H. F.; Sequeira, C. A. C.; Pereira, P.Applied Physics Letters, 89 ; Nanostructuring of fullerene C60 beam deposited films is achieved by electrochemical reduction in a potassium hydroxide aqueous solution. Alkali fulleride clusters are formed at the electrode, as it is illustrated by cyclic voltammetry, x-ray diffraction, and scanning tunneling microscopy. Fluorescence emission from fluorophore doped fullerene reduced films was investigated by flu...
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