36 research outputs found
Supercritical Fluid Extraction Of A High-ash Brazilian Mineral Coal
No full textThe effects of extraction temperature, solvent density and addition of cosolvents on the conversion, liquid yield and also on the characteristics of the extracts and residues from SCFE with toluene of a high-ash Brazilian mineral coal were experimentally investigated (Rocha [1]). The experiments were performed in a semi-batch laboratory-scale unit in the coal pyrolysis region - 593 to 673 K and with pressures up to 11.5 MPa. It was observed a reduction in the total sulfur content up to 44%, whereas providing residues with maximum losses of 16% of the original heat-content. The extracts were characterized by a reliable, non-destructive Preparative Liquid Chromatography method - PLC-8 (Karam et al. [2]), providing eight discrete fractions with well defined chemical functionality. With the addition of 5 mol% tetralin 21.7% conversion was obtained, that means an increase of 15% when compared to pure toluene, while with n-methyl-2-pyrrolidone (NMP) and ethanol the conversion decreased. © 1996 Elsevier B.V. All rights reserved.12C185190Rocha, S.R.P., (1995) M.Sc. Thesis, Federal University of Santa Catarina, Brazil, , 161pKaram, H.S., McNair, H.M., Lanças, F.M., (1987) LC-GC, 5, p. 41Gangoli, N., Thodos, G., (1977) Ind. Eng. Chem. Prod. Res. Dev., 16, p. 208Lanças, F.M., Vilegas, J.H.Y., Martins, S., Gobato, E.A.F., (1994) J. of High Resolution Chromatography, 17, p. 237Peng, D.Y., Robinson, D.B., (1976) Ind. Eng. Chem. Fundam., 15, p. 59Sakaki, T., Shibata, M., Adachi, Y., Hirosue, H., (1994) Fuel, 73, p. 515Cahill, P., Harrison, G., Lawson, G.J., (1989) Fuel, 68, p. 1152Kershaw, J.R., Jezko, J., (1982) Separation Science and Technology, 17, p. 151Vasilakos, N.P., Dobbs, J.M., Parisi, A.S., (1985) Ind. Eng. Chem. Process Des. Dev., 64, p. 883Canel, M., Hedden, K., Wilhelm, A., (1990) Fuel, 69, p. 47
Extração de compostos volateis de carvões minerais utilizando-se fluidos supercriticos
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnologic
Frequencies Of The -330 (t → G) Il-2 And -590 (t → C) Il-4 Gene Polymorphisms In A Population From South-eastern Brazil
No full textPolymorphisms in the promoter regions of cytokine genes may affect their transcription. A T/G substitution at position?330 of the interleukin-2 (IL-2) gene and a T/C substitution at position -590 of the interleukin-4 (IL-4) gene have been described previously. The -590 (T → C) IL-4 gene polymorphism was associated with asthma and atopy in US and Japanese populations. Population genetics is a useful tool for determination of the biological significance of genetic polymorphisms. The aim of this study was to investigate the frequencies of polymorphisms in the promoter regions of the IL-2 and IL-4 genes in a population from south-eastern Brazil and to compare them with those published for other populations. Allele frequencies were estimated in 114 unrelated individuals from São Paulo State. These subjects had an average age of 41.2 years (± 12.4 years) and the ethnic composition of the sample was: 78.07% Caucasian, 11.4% Black and 10.53% Mulatto. DNA from subjects was extracted from epithelial buccal cells, and the PCR-RFLP technique was employed to investigate the -330 (T → G) IL-2 and -590 (T → C) IL-4 gene polymorphisms. The allele frequency of the IL-2 gene polymorphism obtained in our study was similar to that found in UK Caucasoid groups. The T allele frequency of the IL-4 gene polymorphism observed in the Caucasian Brazilian group was similar to that found in UK and Australian populations, while the frequency observed for the Black Brazilian group was similar to that found in Japanese and Kuwaiti Arab populations. The results for the -330 (T → G) IL-2 and -590 (T → C) IL-4 polymorphisms are consistent with the high contribution of European lineages to the population in south-eastern Brazil.294293296Alves-Silva, J., Da Silva Santos, M., Guimaraes, P.E.M., Ferreira, A.C.S., Bandelt, H.-J., Pena, S.D.J., Prado, V.P., The ancestry of Brazilian mtDNA lineages (2000) American Journal of Human Genetics, 67, p. 444Arpini-Sampaio, Z., Costa, M.C.B., Melo, A.A., Carvalho, M.F.V.A., Deus, M.S.M., Simões, A.L., Genetic polymorphisms and ethnic admixture in African-derived Black communities of Notheastern Brazil (1999) Human Biology, 71, p. 69Callegari-Jacques, S.M., Salzano, F.M., Brazilian Indian/non-Indian interactions and their effects (1999) Ciência e Cultura, 51, p. 166Carvalho-Silva, D.R., Santos, F.R., Rocha, J., Pena, S.D., The phylogeography of Brazilian Y-chromosome lineages (2001) American Journal of Human Genetics, 68, p. 281Chen, Y.S., Torroni, A., Excoffier, L., Santachiara-Benerecetti, A.S., Wallace, D.C., Analysis of mtDNA variation in African populations reveals the most ancient of all human continent-specific haplogroups (1995) American Journal of Human Genetics, 57, p. 133Constans, J., DNA and protein polymorphism: Application to anthropology and human genetics (1988) Anthropologischer Anzeiger, 46, p. 97Faucz, F.R., Probst, C.M., Petzl-Erler, M.L., Polymorphism of LMP2 and TAP1, LMP7 and TAP2 in Brazilian Amerindians and Caucasoids: Implications for the evolution of allelic and haplotypic diversity (2000) European Journal of Immunogenetics, 27, p. 5Hijazi, Z., Haider, M.Z., Interleukin-4 gene promoter polymorphism [C590T] and asthma in Kuwaiti Arabs (2000) International Archives of Allergy and Immunology, 122, p. 190(2000) Brasil: 500 anos de Povoamento, , IBGE, Rio de JaneiroJohn, S., Turner, D., Donn, R., Sinnot, P., Worthington, J., Ollier, W.E.R., Hutchinson, I.V., Hajeer, A.H., Two novel biallelic polymorphism in the IL-2 gene (1998) European Journal of Immunogenetics, 25, p. 419Kornman, K.S., Crane, A., Wang, H.-Y., Di Giovine, F.S., Newman, M.G., Pirk, F.W., Wilson T.G., Jr., Duff, G.W., The interleukin-1 genotype as a severity factor in adult periodontal disease (1997) Journal of Clinical Periodontology, 24, p. 72Lazarus, M., Hajeer, A.H., Turner, D., Sinnott, P., Worthington, J., Ollier, W.E.R., Hutchinson, I.V., Genetic variation in the interleukin-10 gene promoter and systemic lupus erythematosus (1997) Journal of Rheumatology, 24, p. 2314Noguchi, E., Shibasaki, M., Arinami, T., Takeda, K., Yokouchi, Y., Kawashima, T., Yanagi, H., Hamaguchi, H., Association of asthma and the interleukin-4 promoter gene in Japanese (1998) Clinical and Experimental Allergy, 28, p. 449Probst, C.M., Bompeixe, E.P., Pereira, N.F., De Dalalio, M.M.O., Visentainer, J.E.I., Tsuneto, L.T., Petzl-Erler, M.L., HLA polymorphism and evaluation of European, African and Am erindian contribution to the white and mulatto populations from Paraná, Brazil (2000) Human Biology, 72, p. 597Reynard, M.P., Turner, D., Navarrete, C.V., Allele frequencies of polymorphisms of the tumor necrosis factor-α, interleukin-10, interferon-γ and interleukin-2 genes in a North European Caucasoid group from the UK (2000) European Journal of Immunogenetics, 27, p. 241Rosenwasser, L.J., Klemm, D.J., Dresback, J.K., Promoter polymorphisms in the chromosome 5 gene cluster in asthma and atopy (1995) Clinical and Experimental Allergy, 25 (SUPPL. 2), p. 74Scarel, R.M., Trevilatto, P.C., Di Hipólito O., Jr., Camargo, L.E.A., Line, S.R.P., Absence of mutations in the homeodomain of the MSX1 gene in patients with hypodontia (2000) American Journal of Medical Genetics, 92, p. 346Scarel-Caminaga, R.M., Trevilatto, P.C., Souza, A.P., Brito R.B., Jr., Line, S.R.P., Investigation of an IL-2 polymorphism in patients with different levels of chronic periodontitis (2002) Journal of Clinical Periodontology, , in pressSoares, J.F., Siqueira, A.L., (1999) Introdução á Estatística Médica, , Departamento de Estatística, Universidade Federal de Minas Gerais, Belo Horizonte, BrazilTrevilatto, P.C., Line, S.R.P., Use of buccal epithelial cells for PCR amplification of large DNA fragments (2000) Journal of Forensic Odonto-Stomatology, 31, p. 393Walley, A.J., Cookson, W.O.C.M., Investigation of an interleukin-4 promoter polymorphism for associations with asthma and atopy (1996) Journal of Medical Genetics, 33, p. 689Woolf, B., On estimating the relation between blood groups and disease (1955) Annals of Human Genetics, 19, p. 25
A Three-phase Ternary Model For Co2-solid-liquid Equilibrium At Moderate Pressures
No full textIn this work, we present a simple, totally predictive, three-phase modeling for systems containing CO2-solid-liquid for evaluation of cosolvents in the supercritical-fluid extraction (SCFE) of volatile matter of Brazilian mineral coals. The liquid phase is modeled by the traditional regular solution theory while the gas phase is represented by the Peng-Robinson/Stryjek-Vera equation of state and the heavy component is taken as a pure solid. In the liquid phase, supercritical CO2 is considered a hypothetical liquid, its standard fugacity being given by a specific correlation. The results of the solid-liquid-gas equilibrium calculations are in good agreement with experimental data of the mixture CO2-naphthalene-toluene1 at moderate pressures although no adjustable parameters were used. When a liquid phase is present, the results of the simulations involving the mixtures CO2-naphthalene-toluene and CO2-naphthalene-n-pentane indicate higher concentrations of naphthalene in the gas phase when the cosolvent is n-pentane. These results show that both the solid-cosolvent interactions and the volatility of the cosolvent should be taken into account.9115Hong, S.P., Luks, K.D., (1992) Fluid Phase Equil., 74, p. 133Brunner, G., (1983) Fluid Phase. Equil., 10, p. 289Dobbs, J.M., Wong, J.M., Johnston, K.P., (1986) J. Chem. Eng. Data, 31, p. 303Dobbs, J.M., Wong, J.M., Lahiere, R.J., Johnston, K.P., (1987) Ind. Eng. Chem. Res., 26, p. 56Sunol, A.K., (1982), Ph.D. Dissertation, Virginia Polytechnic Institute and State University, BlacksburgLemert, R.M., Johnston, K.P., (1991) Ind. Eng. Chem. Res., 30, p. 1222Schaffer, S.T., Zalkow, L.H., Teja, A.S., (1988) Fluid Phase. Equil., 43, p. 45Harcharan, S., Jimmy Yun, S.L., Macnaughton, S.J., Tomasko, D.L., Foster, N.R., (1993) Ind. Eng. Chem. Res., 32, p. 2841Kurnik, R.T., Holla, S.J., Reid, R.C., (1981) J. Chem. Eng. Data, 26, p. 47Lemert, R.M., Johnston, K.P., (1989) Fluid Phase Equil., 45, p. 265Stryjek, R., Vera, J.H., (1986) Can. J. Chem. Eng., 64, p. 323Sandler, I.S., (1989) Chemical and Engineering Thermodynamics, 2nd Ed., , John Wiley & Sons: New YorkSchmitt, W.J., Reid, R.C., (1986) J. Chem. Eng. Data, 31, p. 204Coon, J.E., Auwaerter, J.E., Mclaughlin, E., (1989) Fluid Phase. Equil., 44, p. 305Barton, A., (1983) Handbook of Solubility Parameters and Other Cohesive Parameters, , CRC Press: Boca Raton, FLCanjar, L.N., Manning, F.S., (1967) Thermodynamic Properties and Reduced Correlation for Gases, , Gulf Publishing: Houston, TXVargaftik, N.B., (1975) Tables on the Thermophysical Properties of Liquids and Gases, 2nd. Ed., , Hemisphere: New YorkJohnston, K.P., Peck, D.G., Kim, S., (1989) Ind. Eng. Chem. Res., 28, p. 111
Distant Retrograde Orbits: Modeling and Stability
No full textDistant Retrograde Orbits (DROs) are special orbits for third bodies in two-body systems. The third body revolves around the secondary – the smaller of the two primaries – in a retrograde way, meaning the direction is opposite to the direction that the primaries revolve around each other. DROs are not close to either of the primaries, making it difficult to model them as perturbed two-body orbits.There is no analytical solution for the initial conditions of DROs. This thesis presents a novel method of calculating an initial velocity guess which is then fed into a differential corrector that is able to calculate the initial conditions. In contrast to the state-of-the-art, this happens without the method of incremental steps in the initial position, which requires to go through all possible DROs for a specific two-body system first.For the calculation of DROs, numerical integration is done. Optimal integrator settings are determined, which is in this case an eighth-order Runge-Kutta method (RK8). By setting the tolerance to the lowest possible value, the accuracy requirements are satisfied.Furthermore, this thesis explores a different method of modeling DROs that makes use of Fourier series and polynomials, which had already been proposed by Hirani in 2006 for a different set of parameters. By exploiting explicit knowledge about the shape of DROs, this approach is made more efficient in terms of accuracy per Fourier/polynomial parameters needed and thus the computation time is enhanced.The second part of this study addresses the stability of DROs. This is analyzed in order to get an idea of what DROs would be suitable for future missions. For mass ratios of primary and secondary that realistically occur in the Solar System, all DROs that are closer to the secondary than the primary turn out to be stable when disregarding perturbations. Perturbations are modeled as a constant external acceleration with a constant direction, which is only a first step towards modeling the Sun's and other planet's point mass gravity (p.m.g.), the solar radiation pressure (s.r.p.), and other perturbations, as they are usually depending on time and position. With this rough estimate, only the Sun's p.m.g. is identified as a possible source of instability for DROs in the Earth-Moon system, as all other perturbations are too small.Aerospace Engineerin
Polymeric amorphous carbon as p-type window within amorphous silicon solar cells
No full textAmorphous carbon (a-C) has been shown to be intrinsically p-type, and polymeric a-C (PAC) possesses a wide Tauc band gap of 2.6 eV. We have replaced the p-type amorphous silicon carbide layer of a standard amorphous silicon solar cell with an intrinsic ultrathin layer of PAC. The thickness of the p layer had to be reduced from 9 to 2.5 nm in order to ensure sufficient conduction through the PAC film. Although the resulting external parameters suggest a decrease in the device efficiency from 9.2% to 3.8% due to a reduced value of open-circuit voltage, the spectral response shows an improvement in the 400–500-nm wavelength range, as a consequence of the wider band gap of the PAC layer.Electrical Sustainable EnergyElectrical Engineering, Mathematics and Computer Scienc
Rapid recovery of genetic diversity of stomatopod populations on Krakatau : temporal and spatial scales of marine larval dispersal
No full textAuthor Posting. © Royal Society, 2002. This article is posted here by permission of Royal Society for personal use, not for redistribution. The definitive version was published in Proceedings of the Royal Society of London B 269 (2002): 1591-1597, doi:10.1098/rspb.2002.2026.Although the recovery of terrestrial communities shattered by the massive eruption of Krakatau in 1883 has been well chronicled, the fate of marine populations has been largely ignored. We examined patterns of genetic diversity in populations of two coral reef-dwelling mantis shrimp, Haptosquilla pulchella and Haptosquilla glyptocercus (Stomatopoda: Protosquillidae) , on the islands of Anak Krakatau and Rakata. Genetic surveys of mitochondrial cytochrome oxidase c (subunit 1) in these populations revealed remarkably high levels of haplotypic and nucleotide diversity that were comparable with undisturbed populations throughout the Indo-Pacific. Recolonization and rapid recovery of genetic diversity in the Krakatau populations indicates that larval dispersal from multiple and diverse source populations contributes substantially to the demographics of local populations over intermediate temporal (tens to hundreds of years) and spatial scales (tens to hundreds of kilometres). Natural experiments such as Krakatau provide an excellent mechanism to investigate marine larval dispersal and connectivity. Results from stomatopods indicate that marine reserves should be spaced no more than 50-100 km apart to facilitate ecological connectivity via larval dispersal.P.H.B. acknowledges support of a NSF Minority
Postdoctoral Fellowship. Research was funded by grants
to S.R.P. A Putnam grant supported fieldwork
Formação Docente e Competências: Componentes do Processo de Gestão Estratégica.
No full textO presente artigo aborda a gestão estratégica das Instituições de Ensino Superior IES da área de Administração, sugerindo a visualização de determinados elementos críticos no contexto brasileiro. Tem como objetivo promover a reflexão crítica acerca da formação docente enquanto elemento central nesse processo. Versa sobre a eficácia no processo de ensino-aprendizagem e alcance de objetivos institucionais. Sugere a adoção de uma visão integrada que permita associar o perfil discente, as características do quadro curricular e a ação docente enquanto elementos de um processo único de gestão institucional. Trata-se de trabalho qualitativo e exploratório, representando um ensaio teórico orientado à exposição lógico-reflexiva. As conclusões apontam a necessidade de uma compreensão mais abrangente, por parte das IES, acerca do significado da expressão gestão estratégica e da relevância da formação docente na dinâmica institucional. O conteúdo está estruturado em cinco itens. Sendo o primeiro a introdução contendo o tema, o objetivo e a questão central. O segundo comporta a revisão da literatura, aspectos do contexto, objetivos das IES, conceitos e fatores relacionados à formação de competência e ação docente. O terceiro apresenta a metodologia. O quarto indica os resultados e, finalmente, o quinto revela as conclusões
