17 research outputs found

    Titan's lakes chemical composition: sources of uncertainties and variability

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    Between 2004 and 2007 the instruments of the CASSINI spacecraft discovered hydrocarbon lakes in the polar regions of Titan. We have developed a lake-atmosphere equilibrium model allowing the determination of the chemical composition of these liquid areas. The model is based on uncertain thermodynamic data and precipitation rates of organic species predicted to be present in the lakes and seas that are subject to spatial and temporal variations. Here we explore and discuss the influence of these uncertainties and variations. The errors and uncertainties relevant to thermodynamic data are simulated via Monte-Carlo simulations. Global Circulation Models (GCM) are also employed in order to investigate the possibility of chemical asymmetry between the south and the north poles, due to differences in precipitation rates. We find that mole fractions of compounds in the liquid phase have a high sensitivity to thermodynamic data used as inputs, in particular molar volumes and enthalpies of vaporization. When we combine all considered uncertainties, the ranges of obtained mole fractions are rather large (up to ~8500%) but the distributions of values are narrow. The relative standard deviations remain between 10% and ~300% depending on the compound considered. Compared to other sources of uncertainties and variability, deviation caused by surface pressure variations are clearly negligible, remaining of the order of a few percent up to ~20%. Moreover no significant difference is found between the composition of lakes located in north and south poles. Because the theory of regular solutions employed here is sensitive to thermodynamic data and is not suitable for polar molecules such as HCN and CH3CN, our work strongly underlines the need for experimental simulations and the improvement of Titan's atmospheric models.Comment: Accepted in Planetary and Space Scienc

    PVT Property Measurements for Some Aliphatic Esters from (298 to 393) K and up to 35 MPa

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    The results of PVT measurements of the liquid phase within the temperature range of (298 to 393) K and up to 35 MPa are presented for some aliphatic esters. Measurements were made by means of a vibrating-tube densimeter, model DMA 512P from Anton Parr. The calibration of the densimeter was performed with water and n-heptane as reference fluids. The experimental PVT data have been correlated by a Tait equation. This equation gives excellent results when used to predict the density of the esters using the method proposed by Thomson et al. (AIChE J. 1982, 28, 671−676). Isothermal compressibilities, isobaric expansivities, thermal pressure coefficients, and changes in the isobaric heat capacity have been calculated from the volumetric data

    Construction of a manual of work processes and techniques from centro de dispensação de medicamentos de alto custo (cedmac), hospital de clínicas, unicamp

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    The Centers for High Cost Medication (Centros de Medicação de Alto Custo, CEDMAC), Health Department, São Paulo were instituted by project in partnership with the Clinical Hospital of the Faculty of Medicine, USP, sponsored by the Foundation for Research Support of the State of São Paulo (Fundação de Amparo à Pesquisa do Estado de São Paulo, FAPESP) aimed at the formation of a statewide network for comprehensive care of patients referred for use of immunobiological agents in rheumatological diseases. The CEDMAC of Hospital de Clínicas, Universidade Estadual de Campinas (HC-Unicamp), implemented by the Division of Rheumatology, Faculty of Medical Sciences, identified the need for standardization of the multidisciplinary team conducts, in face of the specificity of care conducts, verifying the importance of describing, in manual format, their operational and technical processes. The aim of this study is to present the methodology applied to the elaboration of the CEDMAC/HC-Unicamp Manual as an institutional tool, with the aim of offering the best assistance and administrative quality. In the methodology for preparing the manuals at HC-Unicamp since 2008, the premise was to obtain a document that is participatory, multidisciplinary, focused on work processes integrated with institutional rules, with objective and didactic descriptions, in a standardized format and with electronic dissemination. The CEDMAC/HC-Unicamp Manual was elaborated in 10 months, with involvement of the entire multidisciplinary team, with 19 chapters on work processes and techniques, in addition to those concerning the organizational structure and its annexes. Published in the electronic portal of HC Manuals in July 2012 as an e-Book (ISBN 978-85-63274-17-5), the manual has been a valuable instrument in guiding professionals in healthcare, teaching and research activities.The Centers for High Cost Medication (Centros de Medicação de Alto Custo, CEDMAC), Health Department, São Paulo were instituted by project in partnership with the Clini- cal Hospital of the Faculty of Medicine, USP, sponsored by the Foundation for Researc543185191sem informaçãosem informaçã

    Fatigue Behaviour of T Welded Joints Rehabilitated by Tungsten Inert Gas and Plasma Dressing

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    This paper concerns a fatigue study on the effect of tungsten inert gas (TIG) and plasma dressing in non-load-carrying fillet welds of structural steel with medium strength. The fatigue tests were performed in three point bending at the main plate under constant amplitude loading, with a stress ratio of R = 0.05 and a frequency of 7 Hz. Fatigue results are presented in the form of nominal stress range versus fatigue life (S–N) curves obtained from the as welded joints and the TIG dressing joints at the welded toe. These results were compared with the ones obtained in repaired joints, where TIG and plasma dressing were applied at the welded toes, containing fatigue cracks with a depth of 3–5 mm in the main plate and through the plate thickness. A deficient repair was obtained by TIG dressing, caused by the excessive depth of the crack. A reasonable fatigue life benefits were obtained with plasma dressing. Good results were obtained with the TIG dressing technique for specimens with shallower initial defects (depth lesser than 2.5 mm). The fatigue life benefits were presented in terms of a gain parameter assessed using both experimental data and life predictions based on the fatigue crack propagation law

    Densities and Derived Thermodynamic Properties of Imidazolium-, Pyridinium-, Pyrrolidinium-, and Piperidinium-Based Ionic Liquids

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    In the present work, experimental density measurements are reported along with the derived thermodynamic properties, such as the isothermal compressibility (κT), the isobaric expansivity (αp), and the thermal pressure coefficient (γv) for imidazolium-, pyridinium-, pyrrolidinium-, and piperidinium-based ionic liquids (ILs), namely, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate [C2mim][CF3SO3], 3-methyl-1-propylpyridinium bis(trifluoromethylsulfonyl)imide [C3mpy][NTf2], 1-methyl-1-propylpyrrolidinium bis(trifluoromethylsulfonyl)imide [C3mpyr][NTf2], 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide [C4mpyr][NTf2], and 1-methyl-1-propylpiperidinium bis(trifluoromethylsulfonyl)imide [C3mpip][NTf2] in the pressure (0.10 < P/MPa < 35.00) and temperature (293.15 < T/K < 393.15) domains. These ILs were chosen to provide an understanding of the influence of the cation and anion on the properties under study. Experimental densities are correlated with the Tait equation with an average absolute relative deviation (AARD) better than 0.02 %. It is shown that experimental densities are in good agreement with the densities obtained by the predictive method previously proposed by us.http://dx.doi.org/10.1021/je700670

    Surface and interfacial tensions of the systems water + n-butyl acetate + methanol and water + n-pentyl acetate + methanol at 303.15 K

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    The surface tension in the homogeneous domain of the ternary liquid mixtures water + n-butyl acetate + methanol and water + n-pentyl acetate + methanol as well as of the constituent binaries has been measured at 303.15 K and atmospheric pressure. The respective excess surface tension was correlated as a function of the composition using empirical and thermodynamic-based relations. The liquid interfacial tension was measured in the liquid-liquid equilibrium range at the same conditions of temperature and pressure.http://www.sciencedirect.com/science/article/B6TG2-487TYBG-1/1/a39b0ffcd3de8658fe47103f160785e

    The fusion curves of xenon, krypton, and argon

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    The experimental results on the fusion of the heavier rare gases at very high pressures, obtained in the last 20 years, are examined and analysed in conjunction with the measurements made at lower pressures from 1940 onwards. The parameters in the Simon equation for the melting curves of Xe, Kr, and Ar are determined, and the coordinates of a possible high-pressure {s(fcc) + s(hcp) + l} triple-point are identified for each one of these three elements. The enthalpies of transition of the transformations involved are estimated as well as their respective values of the entropies of transition.http://www.sciencedirect.com/science/article/B6WHM-4R6B2R8-1/1/b0b0f09c6f21e6deaf5d2a51875db54

    Estudo eco-epidemiológico da fauna flebotomínica e dos aspectos ambientais relacionados à transmissão das leishmanioses em um município de Minas Gerais, Brasil, 2015-2016

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    Submitted by Nuzia Santos ([email protected]) on 2020-02-17T18:19:38Z No. of bitstreams: 1 Eco-epidemiological study on sandflies .pdf: 469276 bytes, checksum: b5f91262094ec8987d2446800f196a09 (MD5)Approved for entry into archive by Nuzia Santos ([email protected]) on 2020-02-17T18:25:46Z (GMT) No. of bitstreams: 1 Eco-epidemiological study on sandflies .pdf: 469276 bytes, checksum: b5f91262094ec8987d2446800f196a09 (MD5)Made available in DSpace on 2020-02-17T18:25:46Z (GMT). No. of bitstreams: 1 Eco-epidemiological study on sandflies .pdf: 469276 bytes, checksum: b5f91262094ec8987d2446800f196a09 (MD5) Previous issue date: 2019Universidade Federal de Minas Gerais. Escola de Veterinária. Belo Horizonte, MG, Brasil.Fundação Oswaldo Cruz. Instituto René Rachou. Belo Horizonte, MG, Brasil.Universidade Federal de Minas Gerais. Escola de Veterinária. Belo Horizonte, MG, Brasil.Prefeitura de Belo Horizonte. Secretaria de Saúde. Belo Horizonte, MG, Brasil.Prefeitura de Belo Horizonte. Secretaria de Saúde. Belo Horizonte, MG, Brasil.Fundação Oswaldo Cruz. Instituto René Rachou. Belo Horizonte, MG, Brasil.Fundação Oswaldo Cruz. Instituto René Rachou. Belo Horizonte, MG, Brasil.Fundação Oswaldo Cruz. Instituto René Rachou. Belo Horizonte, MG, Brasil.Estado de Minas Gerais. Fundação Ezequiel Dias. Belo Horizonte, MG, Brasil.Prefeitura de Belo Horizonte. Secretaria de Saúde. Belo Horizonte, MG, Brasil.Universidade Federal de Minas Gerais. Escola de Veterinária. Belo Horizonte, MG, Brasil.Universidade Federal de Minas Gerais. Escola de Veterinária. Belo Horizonte, MG, Brasil.Objetivou-se avaliar a fauna vetorial e os aspectos ambientais e climáticos relacionados à transmissão das leishmanioses. Foi realizado um estudo eco-epidemiológico prospectivo de coleta sistemática de flebotomíneos e inquérito censitário sorológico canino em áreas de um município do Brasil. Para determinar a taxa de prevalência de LVC, foram examinadas amostras de sangue de 1752 cães. Na avaliação entomológica, foram instaladas 24 armadilhas luminosas em 12 residências distribuídas, instaladas no ambiente de peridomicílio e intradomicílio durante 12 meses. Para análise dos aspectos climáticos, utilizou-se a correlação simples de Spearman e para análise espacial foram utilizadas a Lógica Fuzzy e a Função K. A taxa de prevalência em cães foi de 4,1% e 7,1%. No estudo entomológico, foram capturados 431 flebotomíneos. A maior parte (74%) dos espécimes foi capturada no peridomicílio. Em relação à infecção natural, 5,6 % das amostras analisadas por biologia molecular apresentaram positividade à infecção por Leishmania spp.. Em 100% das amostras positivas, encontrou-se infecção por Leishmania infantum. Na análise espacial uma Área apresentou maior concentração de pontos de sobreposição de alta densidade de Lutzomyia longipalpis e cães sororreagentes, indicando maior risco na ocorrência concomitante dos dois eventos. Os resultados mostram que a interface parasito-reservatório-vetor está ativa nas áreas estudadas.The aim of this study was to evaluate Leishmania vectors and investigate the environmental and climatic characteristics related to their transmission. This was a prospective eco-epidemiological study involving the systematic collection of sandflies and a canine serological survey in areas of municipality in Brazil. Blood samples from 1,752 dogs were examined to test for canine visceral leishmaniasis (VL). An entomological evaluation was carried out using 24 light traps in the peridomicile and intradomicile areas of 12 households for 12 months. Climate variables were analyzed using a simple Spearman correlation and a spatial analysis via the fuzzy logic method and K function. The prevalence rate of canine VL was 4.1% and 7.1% in the two areas that were studied, respectively. The entomological study resulted in the capture of 431 sandflies. Most (74%) of the specimens were captured in the peridomiciliary area, and 5.6% of the samples that were analyzed using molecular biology were positive for Leishmania spp. In particular, Leishmania infantum was found in 100% of the positive samples. The spatial analysis showed that one particular area presented a higher concentration of high-density overlapping points of Lutzomyia longipalpis and seropositive dog populations, indicating a higher risk of the concomitant occurrence of both events. The results show that a parasite-reservoir-vector interface is active in the studied areas
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