Navegando por Autor "Rosenhaim, R."

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Rheology and MT-DSC studies of the flow properties of ethyl and methyl babassu biodiesel and blends
(Springer, 2011-02-27) Bicudo, Tatiana de Campos; Santos, N. A.; Rosenhaim, R.; Dantas, M. B.; Cavalcanti, E. H. S.; Barro, A. K.; Santos, I. M. G.; Souza, A. G.
Biodiesel is an increasingly attractive alternative to diesel fuel. The main component of Babassu biodiesel is lauric acid (C12:0), which is a saturated fatty acid with a high melting point. Controlling flow properties, such as viscosity and the cold filter plugging point, is critical because viscosity affects atomization, and crystal formation resulting from decreases in temperature can negatively affect engine starting and performance. To evaluate its flow characteristics more fully, the rheological properties of babassu biodiesel were analyzed, taking into account variations in temperature. The crystallization temperature was determined by modulated temperature differential scanning calorimetry (MT-DSC). The curve of biodiesel viscosity as a function of the biodiesel refrigeration temperature contained an inflection point (corresponding to a steep increase in viscosity) that was coincident with both the transition from a Newtonian-type flow to a pseudoplastic-type flow and the crystallization temperature obtained by MT-DSC, indicating that the appearance of crystals in the biodiesel increased its viscosity. The rheological properties of fatty acid methyl and ethyl mixtures (FAME and FAEE) with metropolitan diesel were also evaluated; a higher FAME percentage reduced viscosity in blends up to B100
Thermal investigation of oil and biodiesel fromJatropha curcasL.
(Springer, 2009-06-19) Bicudo, Tatiana de Campos; Freire, L. M. S.; Rosenhaim, R.; Sinfrônio, F. S. M.; Botelho, J. R.; Carvalho Filho, J. R.; Santos, Ieda Maria Garcia dos; Fernandes Júnior., V. J.; Antoniosi Filho, N. R.; Souza, A. G.
Biodiesel is susceptible to autoxidation if exposed to air, light and temperature, during its storage. Physic nut (Jatropha curcas L.) seeds show potential application for biodiesel production since its oil yields high quality biodiesel. This work aims to evaluate the thermal behavior of the physic nut oil and biodiesel, from several Brazilian crops, by means of thermoanalytical techniques. Thermogravimetry (TG) and pressurized-ifferential scanning calorimetry (PDSC) were used in order to determine the applicability of physic nut biodiesel as fuel. Results suggest that physic nut biodiesel is a practical alternative as renewable and biodegradable fuel able to be used in diesel motors
Thermal study of CoxZn7-xSb2O12 spinel obtained by pechini method using different alcohols
(Springer, 2004-02) Gouveia, Deiby Santos; Rosenhaim, R.; Maurera, M. A. M. A. de; Lima, Severino Jackson Guedes; Paskocimas, Carlos Alberto; Silva, Elson Longo da; Souza, Antônio Gouveia de; Santos, Ieda Maria Garcia dos
With the aim of obtaining materials with applications in pigments, CoxZn7–xSb2O12 spinels were synthesized using the Pechini method. This method consists in the formation of a polymeric net, where the metallic cations are homogeneously distributed. In this work, two types of alcohol (ethyl glycol and ethylene glycol) were used for the synthesis of a zinc antimoniate spinel, CoxZn7–xSb2O12 (x=0–7). The materials were characterized by termogravimetry (TG) and differential thermal analysis (DTA). TG results indicated a decrease in total mass loss when cobalt was added to the solution substituting zinc, for samples prepared using the two different alcohols. Decomposition temperatures, obtained by TG and DTA, presented a decreasing behavior as cobalt was added to the material. In relation to the alcohols, all results indicated a better polymerization of the resin when ethylene glycol was used, being the most indicated one for cation immobilization. X-ray diffraction did not show differences between the two alcohols – both presented the spinel phase (Co, Zn)2.33Sb0.67O4. Samples with higher quantity of cobalt also presented ilmenite phase (Co, Zn)Sb2O6

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Navegando por Autor "Rosenhaim, R."