3 resultados para Equacoes diferenciais parciais

em Universidade Federal de Uberlândia


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Biodiesel is a renewable fuel derived from vegetable oils or animal fats, which can be a total or partial substitute for diesel. Since 2005, this fuel was introduced in the Brazilian energy matrix through Law 11.097 that determines the percentage of biodiesel added to diesel oil as well as monitoring the insertion of this fuel in market. The National Agency of Petroleum, Natural Gas and Biofuels (ANP) establish the obligation of adding 7% (v/v) of biodiesel to diesel commercialized in the country, making crucial the analytical control of this content. Therefore, in this study were developed and validated methodologies based on the use of Mid Infrared Spectroscopy (MIR) and Multivariate Calibration by Partial Least Squares (PLS) to quantify the methyl and ethyl biodiesels content of cotton and jatropha in binary blends with diesel at concentration range from 1.00 to 30.00% (v/v), since this is the range specified in standard ABNT NBR 15568. The biodiesels were produced from two routes, using ethanol or methanol, and evaluated according to the parameters: oxidative stability, water content, kinematic viscosity and density, presenting results according to ANP Resolution No. 45/2014. The built PLS models were validated on the basis of ASTM E1655-05 for Infrared Spectroscopy and Multivariate Calibration and ABNT NBR 15568, with satisfactory results due to RMSEP (Root Mean Square Error of Prediction) values below 0.08% (<0.1%), correlation coefficients (R) above 0.9997 and the absence of systematic error (bias). Therefore, the methodologies developed can be a promising alternative in the quality control of this fuel.

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This work contributes to the finance literature proposing to analyze the relationship between the degree of internationalization of Brazilian companies and the likelihood of delisting. Therefore, even though the internationalization as a differential, in the formulation of hypotheses and analysis of the relationship between the variables dealt with concepts and theories within the Corporate Governance, which is already established in theory when it comes to delisting. First, with a view to the theory of internalization, which gives competitive advantages to the company due the adoption internationalization strategy and in parallel to the positive effects that this strategy generates on firms performance, it was formulated an hypothesis that the degree of internationalization would be adversely related to the probability of delisting, mainly due to such benefits generated to the organization. In turn, as an alternative hypothesis of the research, it proposed a positive relationship between these variables, based on agency theory, according to which internationalization would contribute to delisting by increasing geographical separation between shareholders and managers and, consequently, agency conflicts and the difficulty of monitoring. For the achievement of objectives, as well as being included economic and financial variables and GC, it was proposed the analysis of periods of crisis, as the events of recent past of the Brazilian economy. Starting from a base model initially developed by Pour and Lasfer (2013), which later, the proxies of internationalization and crisis have been added also contemplating adjustments to the Brazilian context. The data collected include the period from 2006 to 2014 and information on active and inactive companies at Bovespa. As results, it was found negative significance between the degree of internationalization and the delisting decision, confirming the first hypothesis of the research and stating that the benefits generated by internationalization in the company generate it spreads and results that reduce the probability of delisting. By analyzing the results of control variables was still possible to observe that, even internationalization reducing the likelihood of delisting, by particular aspects of corporate governance in Brazil, such as the high ownership concentration, the benefits it generates contribute to delisting. Regarding the analysis in crisis, the consequences of the crisis of the US subprime in general market were more relevant that the occurrence of itself, unlike the Brazilian internal crisis of 2014, which was statistically significant for the analyzed event. For future researches it is suggested the expansion of database and individual treatment of the reasons adopted by a company when delisting decision.

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In this work, it was developed and validated methodologies that were based on the use of Infrared Spectroscopy Mid (MIR) combined with multivariate calibration Square Partial Least (PLS) to quantify adulterants such as soybean oil and residual soybean oil in methyl and ethyl palm biodiesels in the concentration range from 0.25 to 30.00 (%), as well as to determine methyl and ethyl palm biodiesel content in their binary mixtures with diesel in the concentration range from 0.25 to 30.00 (%). The prediction results showed that PLS models constructed are satisfactory. Errors Mean Square Forecast (RMSEP) of adulteration and content determination showed values of 0.2260 (%), with mean error (EM) with values below 1.93 (%). The models also showed a strong correlation between actual and predicted values, staying above 0.99974. No systematic errors were observed, in accordance to ASTM E1655- 05. Thus the built PLS models, may be a promising alternative in the quality control of this fuel for possible adulterations or to content determination.