Publications Scientifiques

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Author: search.filters.author.Aksas, HammoucheSubject: search.filters.subject.Optimization

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    Optimization of a dermatological cream process formulation from Atractilys Gummifera L roots
    (Aljest, 2021) Larid, R.; Aksas, Hammouche; Touzouirt, S.; Hocine, I.; Kerbouche, R.; Abbadi, M.E.
    Atractilys Gummifera L or glue thistle,is one of the medicinal plants of the Mediterranean area. Belonging to the Asteraceae family, it is used in traditional medicine in various ways (maceration, decoction and fumigation). The rhizome of this plant is used as a healing agent in traditional Algerian medicine: it helps to heal burns. The aim of our work is to optimize the formulation process of a cream for dermatological application based on the roots of Atractilys Gummifera L, by using the methodology of experimental design. The physicochemical characterization of the underground part of this plant reveals a richness in organic substances (sugars 8.5%, lipids 2.29%, Brix degrees 33.34%), and mineral substances (ashes 4.21%). The study of the various parameters considered influential on the formulation process revealed that the optimal conditions for a more stable cream are: the solid (rhizome) / liquid (water) ratio 0.4 (m / V), the stirring time for 15 minutes and the stirring speed 500 rpm. The cream obtained has a rheofluidic (or pseudoplastic) behaviour, which can be described by the Casson model. This behaviour is suitable for a cream for dermatological application
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    Predictive optimization of electrical conductivity of polycarbonate composites at different concentrations of carbon nanotubes: A valorization of conductive nanocomposite theoretical models
    (MDPI, 2021) Sidi Salah, Lakhdar; Ouslimani, Nassira; Chouai, Mohamed; Danlée, Yann; Huynen, Isabelle; Aksas, Hammouche
    Polycarbonate—carbon nanotube (PC-CNT) conductive composites containing CNT concentration covering 0.25–4.5 wt.% were prepared by melt blending extrusion. The alternating current (AC) conductivity of the composites has been investigated. The percolation threshold of the PC-CNT composites was theoretically determined using the classical theory of percolation followed by numerical analysis, quantifying the conductivity of PC-CNT at the critical volume CNT concentration. Different theoretical models like Bueche, McCullough and Mamunya have been applied to predict the AC conductivity of the composites using a hyperparameter optimization method. Through multiple series of the hyperparameter optimization process, it was found that McCullough and Mamunya theoretical models for electrical conductivity fit remarkably with our experimental results; the degree of chain branching and the aspect ratio are estimated to be 0.91 and 167 according to these models. The development of a new model based on a modified Sohi model is in good agreement with our data, with a coefficient of determination R2 = 0.922 for an optimized design model. The conductivity is correlated to the electromagnetic absorption (EM) index showing a fine fit with Steffen–Boltzmann (SB) model, indicating the ultimate CNTs volume concentration for microwave absorption at the studied frequency range. © 2021 by the authors. Licensee MDPI, Basel, Switzerland