Classification of gasoline as with or without dispersant and detergent additives using infrared spectroscopy and multivariate classification

AbstractGasoline may contain additives which can minimize the amount of pollutants emitted to the atmosphere. Detergents and dispersants added to gasoline can reduce gas emissions towards atmosphere and the formation of deposits in engines. The Brazilian Agency of Petroleum, Natural Gas and Biofuel (ANP) has established that Brazilian commercial gasoline must contain detergent and dispersant additives, thus requiring the development of methods for their identification in commercial gasoline. This work proposes a methodology which uses infrared spectra in the medium and near region (MIR and NIR) of the residue of distillation for classification of gasoline samples into two groups: with or without detergent/dispersant additives. The performances of three types of classification methods were compared: linear discriminant analysis (LDA), partial least squares discriminant analysis (PLS-DA) and Support Vector Machines (SVM). Different algorithms for selection of spectral variables for LDA were evaluated: stepwise (SW), genetic algorithm (GA) and successive projections algorithm (SPA). The best results were obtained using LDA/GA or SPA/LDA for MIR region

Práticas Educomunicativas

Esta publicação pretende divulgar as práticas educomunicativas realizadas em diferentes regiões do país e que estão sendo implantadas por nossos associados. O e-book Práticas Educomunicativas, que visa oferecer um material de uso prático que possa servir de apoio pedagógico em diferentes contextos, escolar ou de ações junto a instituições, apresenta 20 artigos de profissionais e pesquisadores que implementam ações que inter-relacionam comunicação e educação no contexto da educação apontando as experiências e processos de educomunicação e valorizando desta forma, o trabalho realizado por cada educomunicador oferecendo, ao leitor, um material de uso prático que possa servir de apoio pedagógico em diferentes contextos

Transferência de calibração em métodos multivariados Calibration transfer in mutivariate methods

<abstract language="eng">Calibration transfer has received considerable attention in the recent literature. Several standardization methods have been proposed for transferring calibration models between equipments. The goal of this paper is to present a general revision of calibration transfer techniques. Basic concepts will be reviewed, as well as the main advantages and drawbacks of each technique. A case study based on a set of 80 NIR spectra of maize samples recorded on two different instruments is used to illustrate the main calibration transfer techniques (direct standardization, piecewise direct standardization, orthogonal signal correction and robust variable selection)