Brandao L.F.P.,Modulo Inc. |
Braga J.W.B.,University of Brasilia |
Suarez P.A.Z.,University of Brasilia
Journal of Chromatography A | Year: 2012
The current legislation requires the mandatory addition of biodiesel to all Brazilian road diesel oil A (pure diesel) marketed in the country and bans the addition of vegetable oils for this type of diesel. However, cases of irregular addition of vegetable oils directly to the diesel oil may occur, mainly due to the lower cost of these raw materials compared to the final product, biodiesel. In Brazil, the situation is even more critical once the country is one of the largest producers of oleaginous products in the world, especially soybean, and also it has an extensive road network dependent on diesel. Therefore, alternatives to control the quality of diesel have become increasingly necessary. This study proposes an analytical methodology for quality control of diesel with intention to identify and determine adulterations of oils and even fats of vegetable origin. This methodology is based on detection, identification and quantification of triacylglycerols on diesel (main constituents of vegetable oils and fats) by high performance liquid chromatography in reversed phase with UV detection at 205. nm associated with multivariate methods. Six different types of oils and fats were studied (soybean, frying oil, corn, cotton, palm oil and babassu) and two methods were developed for data analysis. The first one, based on principal component analysis (PCA), nearest neighbor classification (KNN) and univariate regression, was used for samples adulterated with a single type of oil or fat. In the second method, partial least square regression (PLS) was used for the cases where the adulterants were mixtures of up to three types of oils or fats. In the first method, the techniques of PCA and KNN were correctly classified as 17 out of 18 validation samples on the type of oil or fat present. The concentrations estimated for adulterants showed good agreement with the reference values, with mean errors of prediction (RMSEP) ranging between 0.10 and 0.22% (v/v). The PLS method was efficient in the quantification of mixtures of up to three types of oils and fats, with RMSEP being obtained between 0.08 and 0.27% (v/v), mean precision between 0.07 and 0.32% (v/v) and minimum detectable concentration between 0.23 and 0.81% (v/v) depending on the type of oil or fat in the mixture determined. © 2012 Elsevier B.V..
Study of matrix effect in determination of metals in re-refined basic oils by energy dispersive X-ray fluorescence - EDX [Estudo do efeito de matriz na determinação de metais em óleos básicos rerrefinados por fluorescência de raios X por energia dispersiva]
Melo M.L.S.,Modulo Inc. |
De Souza J.R.,University of Brasilia
Quimica Nova | Year: 2015
In this article, the results of the study of the matrix effect in the determination of metals calcium, chromium, iron, nickel, copper, zinc, molybdenum, cadmium, barium and lead in base oil using Energy Dispersive X-Ray Fluorescence (EDX) are presented. Sensitivities obtained for each calibration curve were evaluated where calcium, chromium, copper, cadmium, barium and lead had the lowest sensitivities. In the case of cadmium, this parameter was lagging and the studies were not carried forward. The curves of the other metals in different base oils were evaluated for linearity. The elements chromium, copper, molybdenum and lead showed linearity problems in some cases. Therefore, curves in different base oils showed distinct mathematical behavior where the matrix effect was confirmed. The other curves were evaluated and existence of the matrix effect attributed to interference of C/H ratio was confirmed in the quantification of all elements. Metals iron, nickel and zinc exhibited the highest sensitivity and determination coefficients, showing that the method has application potential. © 2015, Sociedade Brasileira de Quimica. All rights reserved.
Lopez-Escalante M.C.,University of Malaga |
Caballero L.J.,Modulo Inc. |
Martin F.,University of Malaga |
Gabas M.,University of Malaga |
And 2 more authors.
Solar Energy Materials and Solar Cells | Year: 2016
Crystalline Si solar cells as mounted in photovoltaic modules are historically encapsulated using ethylene-vinyl acetate (EVA) to provide mechanical support, protection against environmental exposure and electrical isolation. Nevertheless, new requirements in the final photovoltaic grid connection cannot successfully be reach by using this polymer current chemical composition. This phenomenon is known as the potential induced degradation (PID). Photovoltaic encapsulant industry has developed innovative materials to overcome this potential aging. One of these new materials is a thermoplastic commonly named as polyolefin. Photovoltaic modules using this encapsulation material have been fabricated in an industrial line and they have been subjected to PID tests. Our results demonstrate that polyolefin can successfully overcome PID test. Therefore it can be considered as a suitable EVA substitutive. © 2015 Elsevier B.V.All rights reserved.
Modulo Inc. | Date: 2013-03-18
Prefabricated non-metallic transportable constructions for recycling centers, concrete. Construction of permanent edifices, masonry.
Perez-Jimenez F.,University of Barcelona |
Valdes G.A.,University of Barcelona |
Valdes G.A.,University of the Frontier |
Botella R.,University of Barcelona |
And 3 more authors.
Construction and Building Materials | Year: 2012
Fatigue is one of the most common causes of damage in bituminous pavements. However, since fatigue characterization requires complex cyclic tests, this property is not usually taken into account when designing bituminous mixtures. The present study introduces a new methodology to assess fatigue behavior of bituminous mixtures by means of a simpler procedure based on a new fracture test called Fénix. Several bituminous mixtures were tested at the Road Research Laboratory of the Technical University of Catalonia using the Fénix test and the three-point bending beam fatigue test, which complies with the new European standard UNE-EN 12697-24:2006. Results show that this new methodology assesses fatigue behavior of bituminous mixes by correlations between both tests. In addition, the procedure can be used to relate stiffness and dissipated energy parameters obtained in the cracking process, which allows the choice of mixtures with better fatigue performance considering the thermal conditions to which mixtures will be subjected during their service life. © 2011 Elsevier Ltd. All rights reserved.