THE EFFECTS OF RATING EXPERIENCE AND DISCOURSE MODES ON ASSESSING EFL LEARNERS WRITING PERFORMANCES

This study aims at investigating the effects of discourse modes on assessing EFL learners written performances. A total of fifty raters judged sixty essays (30 narratives and 30 argumentative writing modes) written by third-year English students from the Faculty of Letters and Humanities. Raters not only scored the compositions but also justified their scores assignments based on written explanations. Raters rating behaviors were diagnosed based on a variety of quantitative and qualitative tools. Essay scores were analyzed based on the statistical model FACETS to measure raters severity and internal consistency, task difficulty, and the scale functioning across writing modes. Qualitative data (gathered from interviews and report forms) were also analyzed in order to examine which aspects of writing were deemed more important than others across task types. The analysis revealed that the discourse mode was substantially an influential factor. The narrative task was more difficult than the argumentative one. Narrative essays were judged harsher than argumentative essays. Less consistent ratings could be detected from the narrative mode, compared to the argumentative one. Qualitative findings showed that the two writing modes were different in their qualitative judgments due to their different genre requirements and norms

Study of Carbonated Clay-Based Phosphate Geopolymer: Effect of Calcite and Calcination Temperature

This study aims to use natural carbonated Tunisian clay as an aluminosilicate precursor for the elaboration of phosphate-based geopolymers, which yields to the valorization of this common material in Tunisia. In addition, the presence of calcium carbonate in this clay allows the investigation of this associated mineral’s effect on the properties of geopolymeric materials. To achieve these purposes, several experimental techniques were used, namely fluorescence (FX), particle size analysis, thermogravimetric analysis (TGA), differential thermal analysis (DTA), dilatometric analysis, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The mechanical strength and the open porosity of the obtained geopolymeric samples were tested by the compression test and the standard test method for water absorption, respectively. The findings of this work show that the used Tunisian clay can present an attractive aluminosilicate precursor for the synthesis of phosphate-based geopolymers. It also shows that the chosen calcination temperature of the raw clay considerably modifies the reactivity of minerals during geopolymerization and, consequently, strongly affects the properties and structure of the geopolymeric samples. These effects were attributed essentially to the formation of new calcium crystalline phases in the obtained geopolymeric samples. In fact, the anorthite (CaAl2Si2O8) phase appears in all the samples but in greater abundance in those obtained from the clay calcined at 550 °C, and the brushite phase (CaHPO4·2H2O) appears only in the samples obtained from the clay calcined at 950 °C. All these new crystalline phases are strongly dependent on the state of the calcite present in the calcined clay