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Porto Alegre, Brazil

Roth L.,Fundacao de Ciencia e Tecnologia | Lorscheitter M.L.,Federal University of Rio Grande do Sul
Revista Brasileira de Botanica

This paper describes the spores of three bryophyte and 28 pteridophyte taxa, and pollen grains of three gymnosperm species preserved in two sedimentary quaternary profiles of Faxinal and Pirataba forests in the northern Coastal Plain of Rio Grande do Sul, Southern Brazil (29°21′S-49°45′W and 29°15′S-49°51′W). We present these data as taxonomic references for paleoenvironmental studies in the region. The profiles were collected using a Hiller Sampler over an interval corresponding to the last 23,000 years, as determined using radiocarbon dating. The chemical processing of the samples followed standard methodology, using HCl, HF, KOH, and acetolysis, and light microscopy was used for analysis. The palynological material was found during the counts of 300 angiosperm pollen grains in each sample, controlled by saturation curves. The descriptions and illustrations are included as well as ecological data from the original organisms. The high taxa diversity found in this study will enhance subsequent plant successional studies, which is essential to paleoenvironmental reconstructions in the Coastal Plain of Southern Brazil. © 2013 Botanical Society of Sao Paulo. Source

Philippsen C.G.,Federal University of Rio Grande do Sul | Vilela A.C.F.,Federal University of Rio Grande do Sul | Zen L.D.,Fundacao de Ciencia e Tecnologia
Journal of Materials Research and Technology

The fluidized bed is a technology that involves multiple phases, allowing for efficient contact between them, therefore it is widely used in the chemical industry, metallurgy, oil and thermal power generation. In fluidized bed processes, the gas-solid interactions and chemical reactions generate a large number of variables to be handled, making the process very complex. Therefore, fluidized bed modeling and simulation is widely used to predict and analyze different processes, but it is possible to find in the literature many mathematical correlations that describe this type of flow. Based on this, the present work presents a review of the main mathematical models that describe the behavior of a fluidized bed reactor, and the state of the art regarding the use of modeling and simulation of the bed to predict and analyze different processes. As a result of this review, we can observe the importance of further development of the hydrodynamic modeling of fluidized beds, where understanding the interactions between the phases and the influence of this interaction is crucial for a better understanding and control of the processes. Generating experimental data of gas-solid and solid-solid interactions is also required for the validation of the numerical models. © 2014 Brazilian Metallurgical, Materials and Mining Association. Source

Fallavena V.L.V.,Grande Rio University | De Abreu C.S.,Grande Rio University | Inacio T.D.,Grande Rio University | Pires M.,Grande Rio University | And 4 more authors.
Quimica Nova

The use and characterization of the first Certified Reference Material (CRM) of Brazilian coal for analytical quality control are presented. All results were determined within the limits of repeatability and reproducibility allowed under the standards. Notable among the characterization parameters was the mineral matter content (45.39%) obtained by an alternative procedure showing a low relative error (-2.1%) compared to the standard technique (low ashing temperature). The possible expanded application of this CRM application in national laboratories, beyond the certificated and reference parameters, has advantages such as lower cost and easy availability, but round robin tests must be performed. Source

De Oliveira D.M.,Fundacao de Ciencia e Tecnologia | De Oliveira D.M.,Lutheran University of Brazil | Ongaratto D.P.,Fundacao de Ciencia e Tecnologia | Ongaratto D.P.,Lutheran University of Brazil | And 13 more authors.
Quimica Nova

Methanolic transesterification of oils and fats was carried out in a two steps procedure, under basic and acidic catalysis. Palm, soybean, canola, corn, rice, grapeseed, sunflower, peanut, pequi and olive oils, besides tallow and lard were used as feedstock. Specific gravity, relative viscosity, thin layer chromatography and gas chromatography were used to characterize the biodiesel. Biodiesel was obtained in high yield and purity. Results were used to discuss the following key-concepts: 1-triglycerides, composition and properties; 2-nucleophilic acyl substitution under basic and acid conditions, 3-thin layer chromatography, 4-gas chromatography and its quantitative methods. Source

Marques M.V.,Fundacao de Ciencia e Tecnologia | Naciuk F.F.,Fundacao de Ciencia e Tecnologia | De Souza Mello A.M.,Fundacao de Ciencia e Tecnologia | Nair Maria Seibel,Fundacao de Ciencia e Tecnologia | Luiz Antonio Mazzini Fontoura,Fundacao de Ciencia e Tecnologia
Quimica Nova

A method for ester content determination in soybean methyl biodiesel was studied, using ethyl oleate as internal standard. A biodiesel sample was analyzed and had its purity estimated as 92.8%. Method accuracy was evaluated by comparison with the result obtained via EN14103, with a relative difference of 0.1%. Repetitivity and intermediate precision were estimated as 2 and 1.5%, respectively. Source

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