682 research outputs found

    Utilização de co-produtos do biodiesel na reciclagem química de poli(tereftalato de etileno) para produção de novos materiais poliméricos

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    Orientador : Prof. Dr. Luiz Pereira RamosCoorientador : Profª. Drª. Maria Aparecida F. César-OliveiraDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Exatas, Programa de Pós-Graduação em Química. Defesa: Curitiba, 18/12/2008Inclui referências : f. 67-71Resumo: O recente interesse por fontes de energia alternativas, renováveis, de duração ilimitada e baixo impacto ambiental, tem levado ao aumento da utilização e produção de biodiesel, o que implica em crescente disponibilidade de glicerina no mercado exigindo o estudo de novas aplicações para aumentar o consumo desta matéria prima. Por outro lado, o grande aumento da produção e de utilização do PET nos mais variados segmentos do mercado, principalmente no de embalagens, trouxe um grande problema ambiental associado ao descarte das embalagens utilizadas. A reciclagem do PET tem sido uma opção para a solução deste problema, porém a reciclagem química envolvendo compostos polihidroxilados, como o glicerol, que pode dar origem a materiais com propriedades diferenciadas, tem sido pouco estudada. Unindo estas duas importantes demandas, este Trabalho propõe o desenvolvimento de alguns poliésteres aromáticos, de estrutura e propriedades variadas, obtidos a partir do glicerol envolvendo a reciclagem química do poli(tereftalato de etileno), que poderão servir a diversas aplicações com a possibilidade de ter sua arquitetura orientada à obtenção das propriedades adequadas a uma dada aplicação. Neste trabalho foram obtidos produtos de reação da solvólise de poli(tereftalato de etileno) com glicerol, catalisada por acetato de magnésio [Mg(OAc)2]. As condições de reação foram variadas quanto à temperatura, tempo, tipo de catalisador, proporção dos reagentes. Comprovou-se a maior eficiência do Mg(OAc)2 em relação ao acetato de zinco [Zn(OAc)2], o melhor catalisador dentre os metais de transição segundo a literatura. A recuperação dos produtos foi de 95% a 220ºC no período de 5 horas em comparação com 20 horas a 200ºC descritos na literatura. Não foi possível isolar o monômero devido à solubilidade do mesmo, porém logrou-se conseguir a polimerização no mesmo recipiente da reação de solvólise por destilação à vácuo do glicerol em excesso. O s produtos foram caracterizados por 1H-RMN, DSC, GPC, FTIR, índices de hidroxila e acidez. Foram obtidos polímeros com massa molar média ponderal (Mw) entre 3.000 e 7.000 g/mol e, com o uso de tereftalato de dimetila como extensor de cadeia, polímeros com Mw até 11.000 g/mol.Abstract: The recent interest in renewable energy alternative sources, with low environmental impact, has led the increase the production and use of biodiesel, that results in increasing of glycerin availability that require studies to propose new applications to increase the consumption of this raw material. On the other hand, a greater production and use of poly(ethylene terephthalate) - PET - in a several segments, mainly in packaging, has brought a major environmental problem associated with an inappropriate discard of used packaging. PET recycling has been an option to solve this problem, but the chemical recycling involving polyhydroxyl compounds such as glycerol, which may give rise to materials with different properties, has been little investigated. Combining these two important demands, this work presents the development of some aromatic polyesters with different structures and different properties obtained from chemistry recycling of PET using glycerol. These new polyesters might be used in a variety of applications with possibility of having its architecture oriented to obtaining the appropriate properties for a given application. In this work, was possible to obtain polyesters, from PET by solvolysis reactions catalyzed by magnesium acetate [Mg(OAc)2]. Several reaction conditions were investigated, such as, temperature, time, type of catalyst, reagents ratio. The efficiency of Mg(OAc)2 was better than zinc acetate [Zn(OAc)2], the latter being rated the best catalyst among transition metals according the literature. The products were obtained in 95% yield, at 220 °C in 5 hours. This is a better result than that cited by 20 hours at 200 °C using Zn(OAc)2, described in the literature. The new polyesters were made by one-pot synthesis techniques since it was not possible isolate the monomer due to the solubility of the same. Therefore, the polymerization reaction was carried out in the same bottle where it has been the reaction of solvolysis by distillation of glycerol excess in the reduced pressure. The products were characterized by 1H-NMR, DSC, GPC, FTIR, hydroxyl index and acidity index. The polymers were obtained with average molar mass () between 3,000 and 7,000 g/mol, and using dimethyl terephthalate as a chain extender, polymers of up to 11,000 g/mol were obtained

    Oligocat: Oligoesters as Pseudo-Homogenous Catalysts for Biodiesel Synthesis

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    Biodiesel production from first-generation feedstock has shown a strong correlation with the increase in deforestation and the necessity of larger areas for land farming. Recent estimation from the European Federation for Transport and Environment evidenced that since the 2000s decade, an area equal to the Netherlands was deforested to supply global biodiesel demand, mainly originating from first-generation feedstock. Nevertheless, biodiesel is renewable, and it can be a greener source of energy than petroleum. A promising approach to make biodiesel independent from large areas of farming is to shift as much as possible the biodiesel production chain to second and third generations of feedstock. The second generation presents three main advantages, where it does not compete with the food industry, its commercial value is negligible, or none, and its usage as feedstock for biodiesel production reduces the overall waste disposal. In this manuscript, we present an oligomeric catalyst designed to be multi-functional for second-generation feedstock transesterification reactions, mainly focusing our efforts to optimize the conversion of tallow fat and sauteing oil to FAME and FAEE, applying our innovative catalyst. Named as Oligocat, our catalyst acts as a Brønsted-Lowry acid catalyst, providing protons to the reaction medium, and at the same time, with the course of the reaction, it sequesters glycerol molecules from the medium and changes its physical phase during the transesterification reaction. With this set of properties, Oligocat presents a pseudo-homogenous behavior, reducing the purification and separation steps of the biodiesel process production. Reaction conditions were optimized applying a 42^{2} factorial planning. The output parameter evaluated was the conversion rate of triacylglycerol to mono alkyl esters, measured through gel permeation chromatography (GPC). After the optimization studies, a conversion yield of 96.7 (±1.9) wt% was achieved, which allows classifying the obtained mono alkyl esters as biodiesel by ASTM D6751 or EN 14214:2003. After applying the catalyst in three reaction cycles, Oligocat still presented a conversion rate above 96.5 wt% and as well an excellent recovery rate

    Adaptabilidade e estabilidade de híbridos de milho para o sul do bioma Amazônia via GGE biplot

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    The objective of this work was to select maize hybrids using the GGE biplot analysis, as well as to evaluate their stability and adaptability in different environments of the North and Midwest regions of Brazil. Thirty-six maize hybrids were evaluated in 2018, in the following five environments in the Northern and Midwestern regions, respectively: in the municipality of Vilhena, in the state of Rondônia; and in the municipalities of Sorriso, Sinop, Alta Floresta, and Carlinda, in the Northern region of the state of Mato Grosso. The experimental design was a randomized complete block design. The analysis of variance was performed, and adaptability and stability were estimated by the GGE biplot method based on grain yield performance. A significant interaction between genotypes and environments was detected, and the biplot analysis was efficient in explaining 62.74% of the total variation in the first two principal components, with the formation of three macroenvironments. The 1P2227, 'BRS 3042', and 1P2265 hybrids showed high yield, responsiveness, and stability in the evaluated environments. The DKB310VTPRO2 hybrid was the most unstable genotype. The recommended hybrids are: DKB310 for the Sorriso and Vilhena macroenvironment; 1M1810 and 1O2106 for the Carlinda environment; and 1M1807 for the Sinop environment.O objetivo deste trabalho foi selecionar híbridos de milho, por meio da análise GGE biplot, bem como avaliar sua estabilidade e adaptabilidade em diferentes ambientes das regiões Centro-Oeste e Norte do Brasil. Trinta e seis híbridos de milho foram avaliados em 2018, nos seguintes cinco ambientes das regiões Norte e Centro-Oeste, respectivamente: no município de Vilhena, no estado de Rondônia; e nos municípios de Sorriso, Sinop, Alta Floresta e Carlinda, na região norte do estado de Mato Grosso. O delineamento experimental foi em blocos completos ao acaso. Realizou-se a análise de variância, e estimaram-se a adaptabilidade e a estabilidade pelo método GGE biplot com base na produtividade. Detectou-se interação significativa entre genótipos e ambientes, e a análise biplot foi eficiente para explicar 62,74% da variação total nos dois primeiros componentes principais, com a formação de três macroambientes. Os híbridos 1P2227, 'BRS 3042' e 1P2265 apresentam alta produtividade, capacidade de resposta e estabilidade nos ambientes avaliados. O híbrido DKB310VTPRO2 foi o genótipo mais instável. Os híbridos recomendados são: DKB310 para o macroambiente Sorriso e Vilhena; 1M1810 e 1O2106 para o ambiente Carlinda; e 1M1807 para o ambiente Sinop

    The VISCACHA survey-deep and resolved photometry of star clusters in the Magellanic Clouds

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    The VISCACHA (VIsible Soar photometry of star Clusters in tApii and Coxi HuguA†) Survey is an ongoing project based on deep and spatially resolved photometric observations of Magellanic Cloud star clusters, collected using the SOuthern Astrophysical Research (SOAR) telescope together with the SOAR Adaptive Module Imager. So far we have used >300h of telescope time to observe ∼150 star clusters, mostly with low mass (M < 104M⊠) on the outskirts of the LMC and SMC. With this high-quality data set, we homogeneously determine physical properties using deep colour-magnitude diagrams (ages, metallicities, reddening, distances, mass, luminosity and mass functions) and structural parameters (radial density profiles, sizes) for these clusters which are used as a proxy to investigate the interplay between the Magellanic Clouds and their evolution. We present the VISCACHA survey and its initial results, based on our first two papers. The project's long term goals and expected legacy to the community are also addressed.Fil: Dias, Bruno. European Southern Observatory Chile; Chile. Universidad Andrés Bello; ChileFil: Maia, Francisco. Universidade Federal do Rio de Janeiro; BrasilFil: Kerber, Leandro. Universidade Estadual de Santa Cruz; BrasilFil: Dos Santos, João F. C.. Universidade Federal de Minas Gerais; BrasilFil: Bica, Eduardo. Universidade Federal do Rio Grande do Sul; BrasilFil: Armond, Tina. Universidade Federal de São João del Rei; BrasilFil: Barbuy, Beatriz. Universidade de Sao Paulo; BrasilFil: Fraga, Luciano. Laboratório Nacional de Astrofísica; BrasilFil: Hernandez Jimenez, Jose A.. Universidad Andrés Bello; ChileFil: Katime Santrich, Orlando J.. Universidade Estadual de Santa Cruz; BrasilFil: Oliveira, Raphael A. P.. Universidade de Sao Paulo; BrasilFil: Pérez Villegas, Angeles. Universidade de Sao Paulo; BrasilFil: Piatti, Andres Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Quint, Bruno. Observatorio Gemini; ChileFil: Sanmartin, David. Observatorio Gemini; ChileFil: Angelo, Mateus S.. Centro Federal de Educação Tecnológica de Minas Gerais; BrasilFil: Souza, Stefano O.. Universidade de Sao Paulo; BrasilFil: Vieira, Rodrigo G.. Universidade de Sao Paulo; BrasilFil: Westera, Pieter. Universidad Federal Do Abc; BrasilFil: Parisi, Maria Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Geisler, Doug. Universidad de La Serena; Chile. Universidad de Concepción; ChileFil: Minniti, Dante. Universidad Andrés Bello; Chile. Millennium Institute of Astrophysics; Chile. Vatican Observatory; ItaliaFil: Saito, Roberto. Universidade Federal de Santa Catarina; BrasilFil: Bassino, Lilia Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: de Bórtoli, Bruno Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Figueiredo, André. Universidade de Sao Paulo; BrasilFil: Rímulo, Leandro. Universidad de los Andes; Colombi

    Diretriz da Sociedade Brasileira de Cardiologia sobre Diagnóstico e Tratamento de Pacientes com Cardiomiopatia da Doença de Chagas

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    This guideline aimed to update the concepts and formulate the standards of conduct and scientific evidence that support them, regarding the diagnosis and treatment of the Cardiomyopathy of Chagas disease, with special emphasis on the rationality base that supported it.&nbsp; Chagas disease in the 21st century maintains an epidemiological pattern of endemicity in 21 Latin American countries. Researchers and managers from endemic and non-endemic countries point to the need to adopt comprehensive public health policies to effectively control the interhuman transmission of T. cruzi infection, and to obtain an optimized level of care for already infected individuals, focusing on diagnostic and therapeutic opportunistic opportunities. &nbsp; Pathogenic and pathophysiological mechanisms of the Cardiomyopathy of Chagas disease were revisited after in-depth updating and the notion that necrosis and fibrosis are stimulated by tissue parasitic persistence and adverse immune reaction, as fundamental mechanisms, assisted by autonomic and microvascular disorders, was well established. Some of them have recently formed potential targets of therapies.&nbsp; The natural history of the acute and chronic phases was reviewed, with enhancement for oral transmission, indeterminate form and chronic syndromes. Recent meta-analyses of observational studies have estimated the risk of evolution from acute and indeterminate forms and mortality after chronic cardiomyopathy. Therapeutic approaches applicable to individuals with Indeterminate form of Chagas disease were specifically addressed. All methods to detect structural and/or functional alterations with various cardiac imaging techniques were also reviewed, with recommendations for use in various clinical scenarios. Mortality risk stratification based on the Rassi score, with recent studies of its application, was complemented by methods that detect myocardial fibrosis.&nbsp; The current methodology for etiological diagnosis and the consequent implications of trypanonomic treatment deserved a comprehensive and in-depth approach. Also the treatment of patients at risk or with heart failure, arrhythmias and thromboembolic events, based on pharmacological and complementary resources, received special attention. Additional chapters supported the conducts applicable to several special contexts, including t. cruzi/HIV co-infection, risk during surgeries, in pregnant women, in the reactivation of infection after heart transplantation, and others.&nbsp; &nbsp;&nbsp; Finally, two chapters of great social significance, addressing the structuring of specialized services to care for individuals with the Cardiomyopathy of Chagas disease, and reviewing the concepts of severe heart disease and its medical-labor implications completed this guideline.Esta diretriz teve como objetivo principal atualizar os conceitos e formular as normas de conduta e evidências científicas que as suportam, quanto ao diagnóstico e tratamento da CDC, com especial ênfase na base de racionalidade que a embasou. A DC no século XXI mantém padrão epidemiológico de endemicidade em 21 países da América Latina. Investigadores e gestores de países endêmicos e não endêmicos indigitam a necessidade de se adotarem políticas abrangentes, de saúde pública, para controle eficaz da transmissão inter-humanos da infecção pelo T. cruzi, e obter-se nível otimizado de atendimento aos indivíduos já infectados, com foco em oportunização diagnóstica e terapêutica. Mecanismos patogênicos e fisiopatológicos da CDC foram revisitados após atualização aprofundada e ficou bem consolidada a noção de que necrose e fibrose sejam estimuladas pela persistência parasitária tissular e reação imune adversa, como mecanismos fundamentais, coadjuvados por distúrbios autonômicos e microvasculares. Alguns deles recentemente constituíram alvos potenciais de terapêuticas. A história natural das fases aguda e crônica foi revista, com realce para a transmissão oral, a forma indeterminada e as síndromes crônicas. Metanálises recentes de estudos observacionais estimaram o risco de evolução a partir das formas aguda e indeterminada e de mortalidade após instalação da cardiomiopatia crônica. Condutas terapêuticas aplicáveis aos indivíduos com a FIDC foram abordadas especificamente. Todos os métodos para detectar alterações estruturais e/ou funcionais com variadas técnicas de imageamento cardíaco também foram revisados, com recomendações de uso nos vários cenários clínicos. Estratificação de risco de mortalidade fundamentada no escore de Rassi, com estudos recentes de sua aplicação, foi complementada por métodos que detectam fibrose miocárdica. A metodologia atual para diagnóstico etiológico e as consequentes implicações do tratamento tripanossomicida mereceram enfoque abrangente e aprofundado. Também o tratamento de pacientes em risco ou com insuficiência cardíaca, arritmias e eventos tromboembólicos, baseado em recursos farmacológicos e complementares, recebeu especial atenção. Capítulos suplementares subsidiaram as condutas aplicáveis a diversos contextos especiais, entre eles o da co-infecção por T. cruzi/HIV, risco durante cirurgias, em grávidas, na reativação da infecção após transplante cardíacos, e outros.&nbsp;&nbsp;&nbsp; Por fim, dois capítulos de grande significado social, abordando a estruturação de serviços especializados para atendimento aos indivíduos com a CDC, e revisando os conceitos de cardiopatia grave e suas implicações médico-trabalhistas completaram esta diretriz.&nbsp

    Les droits disciplinaires des fonctions publiques : « unification », « harmonisation » ou « distanciation ». A propos de la loi du 26 avril 2016 relative à la déontologie et aux droits et obligations des fonctionnaires

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    The production of tt‾ , W+bb‾ and W+cc‾ is studied in the forward region of proton–proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98±0.02 fb−1 . The W bosons are reconstructed in the decays W→ℓν , where ℓ denotes muon or electron, while the b and c quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions.The production of ttt\overline{t}, W+bbW+b\overline{b} and W+ccW+c\overline{c} is studied in the forward region of proton-proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98 ±\pm 0.02 \mbox{fb}^{-1}. The WW bosons are reconstructed in the decays WνW\rightarrow\ell\nu, where \ell denotes muon or electron, while the bb and cc quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions

    Forward-central two-particle correlations in p-Pb collisions at root s(NN)=5.02 TeV

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    Two-particle angular correlations between trigger particles in the forward pseudorapidity range (2.5 2GeV/c. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B. V.Peer reviewe

    Event-shape engineering for inclusive spectra and elliptic flow in Pb-Pb collisions at root(NN)-N-S=2.76 TeV

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    Peer reviewe

    Physics case for an LHCb Upgrade II - Opportunities in flavour physics, and beyond, in the HL-LHC era

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    The LHCb Upgrade II will fully exploit the flavour-physics opportunities of the HL-LHC, and study additional physics topics that take advantage of the forward acceptance of the LHCb spectrometer. The LHCb Upgrade I will begin operation in 2020. Consolidation will occur, and modest enhancements of the Upgrade I detector will be installed, in Long Shutdown 3 of the LHC (2025) and these are discussed here. The main Upgrade II detector will be installed in long shutdown 4 of the LHC (2030) and will build on the strengths of the current LHCb experiment and the Upgrade I. It will operate at a luminosity up to 2×1034 cm−2s−1, ten times that of the Upgrade I detector. New detector components will improve the intrinsic performance of the experiment in certain key areas. An Expression Of Interest proposing Upgrade II was submitted in February 2017. The physics case for the Upgrade II is presented here in more depth. CP-violating phases will be measured with precisions unattainable at any other envisaged facility. The experiment will probe b → sl+l−and b → dl+l− transitions in both muon and electron decays in modes not accessible at Upgrade I. Minimal flavour violation will be tested with a precision measurement of the ratio of B(B0 → μ+μ−)/B(Bs → μ+μ−). Probing charm CP violation at the 10−5 level may result in its long sought discovery. Major advances in hadron spectroscopy will be possible, which will be powerful probes of low energy QCD. Upgrade II potentially will have the highest sensitivity of all the LHC experiments on the Higgs to charm-quark couplings. Generically, the new physics mass scale probed, for fixed couplings, will almost double compared with the pre-HL-LHC era; this extended reach for flavour physics is similar to that which would be achieved by the HE-LHC proposal for the energy frontier
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