Alkali treatment was performed on 'Curaua' fibers to improve their mechanical properties. Curaua fibers were dipped into 5%, 10%, and 15% concentrated sodium hydroxide solutions for 1 h and 2 h. The effects of solution concentrations and treatment times on the physical and mechanical properties of curaua fibers were evaluated. Tensile tests of untreated and alkali treated curaua fibers were carried out. Those results showed that the tensile strength of the treated fibers decreased in comparison to untreated fibers, whereas the fracture strain of the treated fibers increased greatly in comparison with that of untreated fibers. In addition, green composites reinforced by untreated and alkali-treated curaua fibers were fabricated by a press forming method. Tensile tests were carried out for both composites. Results showed that both tensile strength and fracture strain of the composite using treated fibers increased in comparison with the composite using untreated fibers.
Purpose: ISO 9001 certification is nowadays considered to be one of the most effective tools that can be adopted for guiding the management of Quality Systems. The stunning growth observed by these standards all over the world confirms a strong polarisation of enterprises' interest in this practice. Owing to the wide incidence of this phenomenon, a deep investigation of ISO 9001 diffusion over time is mandatory and of importance. In line with our previous publications, this paper derives from a research project that we are conducting in Portugal in order to develop the 'ISO 9001 European Scoreboard', aimed at studying and ranking European Union (EU) countries based on the diffusion of quality management systems. Methodology/approach: In order to achieve such a goal, the authors have performed a set of statistical analyses over public data sets. Findings: Based on the model developed and the analyses performed, we were able to identify clusters of countries with different ISO 9001 evolution stages, derived from the ISO 9001 per 1000 inhabitants' scores and countries' growth indexes. Originality: With this scoreboard, we are able to categorise and rank countries based on the quality management systems evolution (growth rates) over the past few years. Ultimately, such an 'ISO 9001 European Scoreboard' will be an instrument to provide a comparative assessment of quality management practices over the EU states, leading to the dynamic evaluation of their 'macroquality' levels achieved, according to such a standard. We believe that such results provide an additional important contribution to the study of management systems diffusion/evolution, aimed at providing more fact-based insights and understandings.
Plant-based natural fibers have a large variation in cross-sectional area. Even in a single fiber the cross-sectional area varies along the fiber-axis. In addition, the shape of the cross-section is not circle, but rather close to an ellipse. Therefore the fiber strength often results in under-or over-estimation. It was observed from cross-sectional micrographs of a curaua fiber green composite that real fiber cross-sectional areas indicated a strong correlation with fiber cross-sectional areas assumed as an ellipse. Based on such correlation, therefore, the present study proposes a new method of determining approximately fiber cross-sectional areas. The validity of the proposed method is shown through elliptical areas calculated from two projection widths, which are measured from two orthogonal directions of single curaua fibers. Moreover, a new probabilistic distribution function based on Weibull theory was created to explain the effect of variation in cross-sectional area along the fiber axis on fiber strength. This function is characterized to decide the statistical properties of fiber strength through a parameter, R, of variation in cross-sectional area.
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