Composition and electronic structure of Zn7-xMxSb2O12 (M = Ni and Co) spinel compounds

The relation between the composition and electronic structure of the perfectly inverse spinel compound Zn7-xMxSb2O12 (M = Ni and Co) has been studied by powder X-ray diffraction and X-ray photoelectron spectroscopy. Changes in the site occupancy are associated with shifts in the core levels as observed in the core level spectral analyses. The configuration of the density of states in the valence band due to the Co and Ni states can be observed in the valence band spectra. (C) 2004 Elsevier B.V. All rights reserved.

NOx and CO emissions and soot presence in partially premixed acoustically excited flames

The pulsating combustion process has attracted interest in current research because its application in energy generation can offer several advantages, such as fuel economy, reduced pollutants formation, increased rate of convective heat transfer and reduced investment, when compared with other new techniques of combustion. An experimental study has been conducted with the objective of investigating the effects of combustion driven acoustic oscillations in the emission rates of combustion gases, especially carbon monoxide and nitrogen oxides, and soot presence in partial premixed flames in confined partially premixed liquefied petroleum gas flames. The results basically showed that a more uniform fuel/air mixture due to the presence of an acoustic field increases the NOx emissions in operations close to stoichiometric equivalence ratios and the frequency is the most important parameter. Carbon monoxide and soot reduced significantly.

ATTENDANCE and CO-OCCURRENCE of BIRDS FOLLOWING ARMY ANTS IN THE ATLANTIC RAIN FOREST

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Electrospray ionization mass spectrometry screening of piperidine alkaloids from Senna spectabilis (Fabaceae) extracts: Fast identification of new constituents and co-metabolites

The fragmentation pattern of a homologous series of piperidine alkaloids isolated from S. spectabilis was investigated using electrospray ionization tandem mass spectrometry (ESI-MS/MS). The ESI-MS and ESI-MS/MS analyses of EtOH extracts and fractions from flowers and fruits of S. spectabilis allowed to elucidate the structures of four new compounds. The identification of these co-metabolites, based on the fragmentation patterns of previously isolated compounds, and further confirmed by accurate mass spectrometry defines this technique as a powerful tool to determine the metabolomic profile of species which has pharmacological importance. ©2005 Sociedade Brasileira de Química.

Thermal behaviour of succinic acid, sodium succinate and its compounds with some bivalent transitions metal ions in dynamic N 2 and CO 2 atmospheres

Thermal stability and thermal decomposition of succinic acid, sodium succinate and its compounds with Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) were investigated employing simultaneous thermogravimetry and differential thermal analysis (TG-DTA) in nitrogen and carbon dioxide atmospheres and TG-FTIR in nitrogen atmosphere. On heating, in both atmospheres the succinic acid melt and evaporate, while for the sodium succinate the thermal decomposition occurs with the formation of sodium carbonate. For the transition metal succinates the final residue up to 1180 °C in N 2 atmosphere was a mixture of metal and metal oxide in no simple stoichiometric relation, except for Zn compound, where the residue was a small quantity of carbonaceous residue. For the CO 2 atmosphere the final residue up to 980 °C was: MnO, Fe 3O 4, CoO, ZnO and mixtures of Ni, NiO and Cu, Cu 2O.

Informe del Décimo Período de Sesiones del Comité de Desarrollo y Cooperación del Caribe, Puerto España, Trinidad y Tabago, 27 a 29 de octubre de 1987 = Report of the Tenth Session of the Caribbean Development and Co-operation Committee, Port-of-Spain, Trinidad and Tobago, 27-29 October 1987

Contiene resumen de las decisiones y recomendaciones, organizacion del periodo de sesiones, resumen de los documentos, resoluciones adoptadas y lista de participantes.

Integración y cooperación regionales en los años ochenta = Regional integration and co-operation in the 1980s

Incluye Bibliografía

Informe del Octavo Período de Sesiones del Comité de Desarrollo y Cooperación del Caribe, Puerto Príncipe, Haití, 6 al 12 de junio de 1984 = Report of the Eighth Session of the Caribbean Development and Co-operation Committee, Port-au-Prince, Haiti, 6-12 June 1984

Presenta la organizacion de la reunion, el resumen de los debates, conclusiones y recomendaciones sobre los temas: ejecucion del programa de trabajo del CDCC desde el 7o periodo de sesiones; proyecto de programa de trabajo para el bienio 1986-1987; accion sobre resoluciones aprobadas en el 6o y 7o periodo de sesiones del CDCC; resoluciones de CEPAL que tienen consecuencias para el CDCC; y admision de las Islas Virgenes Britanicas y las Islas Virgenes de Estados Unidos como miembros asociados del CDCC.