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Recent Publications
Morphological, thermal and physico-chemical properties of Stepa tenacissima L. fibres before and after alkali treatments
materials, an investigation of the effect of alkaline treatment on the physicochemical and
morphological properties of fibres is presented in this work. The fibres extracted from the Alfa
plant were treated with sodium hydroxide (NaOH) at two concentrations (1% and 3%) for 12, 24
and 48 hours immersion time under normal atmospheric conditions. Several techniques have been
used namely: Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and optical
microscopy for the measurement of fibre diameters before and after chemical treatment.
Microscopic observations show a diameter reduction of 6.25% and 32.86% respectively for fibres
treated with 1% and 3% NaOH for 24 hours immersion time compared to untreated ones, as well as
an increase in the roughness of the fibre surfaces has also been noted. In addition, a structural
change due to the decomposition of hemicellulose was shown using FTIR technique for the fibres
treated with 3% NaOH for 12 and 24 hours immersion time. It has been demonstrated by X-ray
diffraction (XRD) that the treatment with NaOH leads to an improvement in the crystallinity of the
fibres.
Citation
M. MOUSSAI Ahmed toufik, (2018), "Morphological, thermal and physico-chemical properties of Stepa tenacissima L. fibres before and after alkali treatments", [international] a3m’2018 , Hammamet, Tunisia
Alkali treatment effects on the physico-chemical and thermal characteristics of Alfa fibers
of fibers extracted from the Alfa plant. The technical fibers were treated with sodium hydroxide (NaOH) at
different concentrations (0.5%, 2% and 3%) for different immersion times: 2, 4, and 8 hours. To do this, several
techniques have been used namely: Fourier transform infrared spectroscopy (FTIR) and thermogravimetric
analysis of their thermal behavior (TGA/DTG). The FTIR spectra clearly showed that the treatment of the fibers
with a 5wt% of NaOH solution for 8 h causes an increase in crystalline transmittance as a criterion of the
intensity of the OH bound linked to the hydrogen. The TGA technique reveals that the thermal decomposition of
the hemicellulose of the treated fibers is carried out at higher temperatures compared to the untreated fibers thus
justifying a weight loss and a development of the crystallite size. In addition, an analysis of the morphology of
the technical fibers was carried out by observations using a binocular photonic microscope, shows that the
impurities on the surface of these fibers are almost totally eliminated by such treatment and the surface has
become rougher, which can lead to an improvement in the quality of the interface fiber/matrix.
Citation
M. MOUSSAI Ahmed toufik, (2018), "Alkali treatment effects on the physico-chemical and thermal characteristics of Alfa fibers", [international] ICAME2018 , Istanbul - Turkey
Influence du traitement thermique sur l’énergie de rupture des cordons de soudure
En contrôle industriel, l’énergie de rupture est souvent un repère de qualité, plus sensible que les caractéristiques de traction, c’est aussi une propriété qui figure dans le plan d’assurance de la qualité du matériau.
L’énergie de rupture est aussi un outil de vérification et comme c’est souvent le cas, elle définit la qualité du matériau. On peut suivant les résultats obtenus, trier les produits fabriqués en fonction des critères de qualité qu’ils remplissent. Pour rendre l’essai de résilience plus sévère et plus représentatif des situations réelles ou des variations de section, on a utilisé des éprouvettes à entaille en V sur les trois cotés du cordon de soudure, vu que la géométrie de l’entaille et sa position sur l’éprouvette est un facteur très important pour l’évaluation de la résistance à la rupture des aciers.
Cette étude nous a permis de constater l’influence de l’épaisseur des échantillons, la position de l’entaille par rapport au cordon et le traitement thermique sur l’énergie de rupture, ainsi q’une dégradation plus importante de taux de contraintes internes par l’augmentation de la ductilité du matériau
Citation
M. MOUSSAI Ahmed toufik, (2006), "Influence du traitement thermique sur l’énergie de rupture des cordons de soudure", [international] JSTS’06 , Alger