Fernanda Carla Bock

CHEMOSTAT, UM SOFTWARE GRATUITO PARA ANÁLISE EXPLORATÓRIA DE DADOS MULTIVARIADOS

The objective of this work was to develop a free access exploratory data analysis software application for academic use that is easy to install and can be handled without user-level programming due to extensive use of chemometrics and its association with applications that require purchased licenses or routines. The developed software, called Chemostat, employs Hierarchical Cluster Analysis (HCA), Principal Component Analysis (PCA), intervals Principal Component Analysis (iPCA), as well as correction methods, data transformation and outlier detection. The data can be imported from the clipboard, text files, ASCII or FT-IR Perkin-Elmer “.sp” files. It generates a variety of charts and tables that allow the analysis of results that can be exported in several formats. The main features of the software were tested using midinfrared and near-infrared spectra in vegetable oils and digital images obtained from different types of commercial diesel. In order to validate the software results, the same sets of data were analyzed using Matlab© and the results in both applications matched in various combinations. In addition to the desktop version, the reuse of algorithms allowed an online version to be provided that offers a unique experience on the web. Both applications are available in English.

PhotoMetrix: An Application for Univariate Calibration and Principal Components Analysis Using Colorimetry on Mobile Devices

This article describes the development of a mobile colorimetric analysis tool. The application, called PhotoMetrix, employs the techniques of simple linear correlation for univariate analysis and principal components analysis (PCA) for multivariate exploratory analysis. The image data are captured by the main camera of the device and converted into red, green and blue (RGB) histograms. As regards the application, the iron determinations were performed in vitamin supplements (univariate module) and differentiation of banknotes was performed by PCA (multivariate module). For the iron determinations, three samples of vitamins at concentrations of 14, 40 and 50 mg of iron per tablet were tested and the results were not statistically significant (p > 0.05) compared to the reference method. The differentiation of banknotes was performed on Brazilian and Argentinean banknotes. The results showed clustering of the same types of banknotes, and through the loadings graph it was possible to observe the variables through the formation of clusters.

Production and usage of a vegetable oil biobased lubricant

Machining is one of the most important manufacturing processes used worldwide in the mechanical industry, and in order to optimize productivity, cutting fluids can be used in the process. Vegetable based fluids present low toxicity as well as good biodegradability and environmental sustainability; however, they also have low oxidative stability. Esters which are obtained from different vegetable oils, maintain the qualities mentioned and provide the required stability. This study presents a production and characterization of the raw materials, methyl esters and epoxidized methyl esters, as well as mainly the comparative evaluation of the cutting fluid formed by these esters with commercial fluids derived from minerals. The emulsions were evaluated regarding the mechanical properties resulting from their use in the process, registration of the temperature obtained during machining, the rough surface the dimensional deviation of the final product and also the evaluation of surface oxidation occurred on the pieces in the medium term. Emulsions containing 5% of esters (methyl and epoxidized methyl) seemed to be the best option, presenting less oxidation of machined pieces, lower working temperature during the process and better surface completion, demonstrating the best performance over the tested fluids.

A Didactic Proposal in Teaching Exploratory Data Analysis with MDF Pictures

This study presents a practical activity adopted in the classroom to aid in comprehension of multivariate tools, particularly in Image principal component analysis (Image PCA), through reproduction of the scores plotted with printed images samples of Medium-Density Fiberboard (MDF). This pedagogical approach allows a more realistic view of the groups formed in the chart, and shows how this technique can be explored in a dynamic manner, allowing a better learning and understanding of the subject. Besides that, this study discloses, among academics, ChemoStat software®, a free software for PCA.