The aims of this work turn towards the valorization of the underutilized Raw Sugar Beet Pulp by-product to produce white Cellulose Microfibers(CMFs),and its potential effect as a reinforcement for the development of H...The aims of this work turn towards the valorization of the underutilized Raw Sugar Beet Pulp by-product to produce white Cellulose Microfibers(CMFs),and its potential effect as a reinforcement for the development of High-Density Polyethylene(HDPE)composites.Pure CMFs were first obtained by subjecting raw SBP to alkali and bleaching treatments.Several characterization techniques were performed to confirm the successful removal of the amorphous compounds from the surface of individual fibers,including SEM,XRD,TGA,and FT-IR analysis.Various CMF loadings(5–10 wt%)were incorporated as bio-fillers into HDPE polymer to evaluate their reinforcing ability in comparison to raw and alkali-treated SBP using twin-screw extrusion followed by injection molding.Styrene–(Ethylene–Butene)–Styrene Three-Block Co-Polymer Grafted with Maleic Anhydride was used as a compatibilizer to improve the interfacial adhesion between fibers and the matrix.Thermal,mechanical,and rheological properties of the produced composite samples were investigated.It was found that the Young’s modulus were gradually increased with increasing of fibers loadings,with a maximum increase of 30%and 26%observed for composite containing 10 wt%of CMFs and raw SBP,respectively,over neat HDPE.While,the use of coupling agent enhances the ductile behavior of the composites.It was also found that all fiber improves the hardness and toughness behavior of all reinforced composites as well as the complex modulus particularly at 10 wt%.The thermal stability slightly increases with the addition of fibers.This study demonstrates a new route for the valorization of SBP by-products.These fibers can be considered as a valuable bio-fillers candidate for the development of composite materials with enhanced properties.展开更多
Our aim is to study the early maladaptive schemas and the memory span abilities and to evaluate the relationship between these schemas and the memory in one side and academic performance in the other side among Morocc...Our aim is to study the early maladaptive schemas and the memory span abilities and to evaluate the relationship between these schemas and the memory in one side and academic performance in the other side among Moroccan students. A cross-sectional study is conducted among 212 students, randomly selected from different institutions of the IBN TOFAIL University, located in the city of Kenitra (NW of Morocco). Three neurocognitive tests are used: the short version of the Early Maladaptive Schemas Questionnaire to evaluate the early maladaptive schemas (EMS), the sub-test of the Wechsler to evaluate the working memory among these subjects, and a general questionnaire about socio-economic data, nutritional and mental health status and also, academic performances of each student. The obtained results showed some significant negative correlations between forward memory span and activated schema, and significant negative correlations are registered between backward memory span and activated schema. More, thirty-three percent of students passed the exams of the autumn term against 67% who failed it. Moreover, significant negative correlations are registered between the schemas and the number of Units validated in the autumn term. In addition, fifty-three percent of students had a normal forward memory, 47% had an excellent forward memory and no one had pathological one. However, 63% had a pathological backward memory span, 28% had normal memory and 9% had an excellent backward memory. The EMS appeared in connection with the student’s working memory and the academic performance. Deeper investigations are needed to understand this relationship and also to study other possible factors that could affect this important neurocognitive function.展开更多
In this paper, we study the dynamic properties of an SIRI epidemic model incorporating media coverage, and stochastically perturbed by a Lévy noise. We establish the existence of a unique global positive solution...In this paper, we study the dynamic properties of an SIRI epidemic model incorporating media coverage, and stochastically perturbed by a Lévy noise. We establish the existence of a unique global positive solution. We investigate the dynamic properties of the solution around both disease-free and endemic equilibria points of the deterministic model depending on the basic reproduction number under some noise excitation. Furthermore, we present some numerical simulations to support the theoretical results.展开更多
基金financial assistance of the Moroccan National Center for Scientific and Technical Research(CNRST)toward this research is hereby acknowledgedThanks to Abou El Kacem QAISS from Moroccan Foundation for Advanced Science,Innovation and Research(MAScIR)for his help to elaborate and characterize all our composites.
文摘The aims of this work turn towards the valorization of the underutilized Raw Sugar Beet Pulp by-product to produce white Cellulose Microfibers(CMFs),and its potential effect as a reinforcement for the development of High-Density Polyethylene(HDPE)composites.Pure CMFs were first obtained by subjecting raw SBP to alkali and bleaching treatments.Several characterization techniques were performed to confirm the successful removal of the amorphous compounds from the surface of individual fibers,including SEM,XRD,TGA,and FT-IR analysis.Various CMF loadings(5–10 wt%)were incorporated as bio-fillers into HDPE polymer to evaluate their reinforcing ability in comparison to raw and alkali-treated SBP using twin-screw extrusion followed by injection molding.Styrene–(Ethylene–Butene)–Styrene Three-Block Co-Polymer Grafted with Maleic Anhydride was used as a compatibilizer to improve the interfacial adhesion between fibers and the matrix.Thermal,mechanical,and rheological properties of the produced composite samples were investigated.It was found that the Young’s modulus were gradually increased with increasing of fibers loadings,with a maximum increase of 30%and 26%observed for composite containing 10 wt%of CMFs and raw SBP,respectively,over neat HDPE.While,the use of coupling agent enhances the ductile behavior of the composites.It was also found that all fiber improves the hardness and toughness behavior of all reinforced composites as well as the complex modulus particularly at 10 wt%.The thermal stability slightly increases with the addition of fibers.This study demonstrates a new route for the valorization of SBP by-products.These fibers can be considered as a valuable bio-fillers candidate for the development of composite materials with enhanced properties.
文摘Our aim is to study the early maladaptive schemas and the memory span abilities and to evaluate the relationship between these schemas and the memory in one side and academic performance in the other side among Moroccan students. A cross-sectional study is conducted among 212 students, randomly selected from different institutions of the IBN TOFAIL University, located in the city of Kenitra (NW of Morocco). Three neurocognitive tests are used: the short version of the Early Maladaptive Schemas Questionnaire to evaluate the early maladaptive schemas (EMS), the sub-test of the Wechsler to evaluate the working memory among these subjects, and a general questionnaire about socio-economic data, nutritional and mental health status and also, academic performances of each student. The obtained results showed some significant negative correlations between forward memory span and activated schema, and significant negative correlations are registered between backward memory span and activated schema. More, thirty-three percent of students passed the exams of the autumn term against 67% who failed it. Moreover, significant negative correlations are registered between the schemas and the number of Units validated in the autumn term. In addition, fifty-three percent of students had a normal forward memory, 47% had an excellent forward memory and no one had pathological one. However, 63% had a pathological backward memory span, 28% had normal memory and 9% had an excellent backward memory. The EMS appeared in connection with the student’s working memory and the academic performance. Deeper investigations are needed to understand this relationship and also to study other possible factors that could affect this important neurocognitive function.
文摘In this paper, we study the dynamic properties of an SIRI epidemic model incorporating media coverage, and stochastically perturbed by a Lévy noise. We establish the existence of a unique global positive solution. We investigate the dynamic properties of the solution around both disease-free and endemic equilibria points of the deterministic model depending on the basic reproduction number under some noise excitation. Furthermore, we present some numerical simulations to support the theoretical results.
