L’enseignement à distance : apports, enjeux et perspectives Cas de l’enseignement supérieur au Maroc

Depuis l’apparition du COVID 19, le mode d’enseignement en vigueur a connu un bouleversement radical passant des cours tenus en  présentiel à des cours virtuels en vue d’assurer une continuité pédagogique. Bien que quelques contraintes exogènes persistent, ce changement de mode d’enseignement a connu un ensemble d’entraves dans sa mise en œuvre affaiblissant sa réussite notamment en termes d’efficacité d’apprentissage.A cet effet, il est opportun d’amorcer une réflexion sur ce sujet. Pour ce faire, cette recherche va aborder trois principaux axes. Le premier sera dédié au contexte d’apparition du concept de l’Enseignement à distance (EAD), ainsi que son évolution. Le second portera sur les apports, les atouts et les handicaps de ce nouveau mode d’enseignement. Le dernier exposera les enjeux et les préoccupations face à l’enseignement à distance dans le contexte marocain.Notre réflexion sera fondée uniquement sur une approche théorique tirée de la littérature, loin de faire l’objet d’une étude empirique

Mechanical Strengths of Modified PET Mortar Composites in Aggressive MgSO4 Medium: ACI & B.S Predictions

Composites mortars based on plastic aggregates are often considered as an innovative materials of the future because of their potential and the advantages they present. In this paper, a comparative study was carried out on the effect of magnesium sulfate MgSO4 (5%) attack on the durability of composite mortars modified by recycled polyethylene terephthalate (PET). Laboratory tests were accomplished on limestone sand and cement mortars where the blended Portland cement was partially replaced by various volume fractions of PET plastic aggregates. Mechanical properties measured on specimens were used to assess the changes in the compressive strengths of PET-mortar composites exposed to MgSO4 attack at different ages, mainly the Young modulus of elasticity. Based on experimental compressive tests on selected specimens and there densities, the evolution of static Young modulus of elasticity has been discussed in accordance to predicted models proposed by (ACI-318) and (BS-8110) codes of practice. In addition, a comparative analysis has been carried out for corrosion resistance coefficients K of referenced mortar to those modified with plastic aggregates. It can be noted that, the corrosion resistance coefficients decrease as much as composite specimens are exposed to MgSO4 corrosive medium. For the case of modified composites, the values of K based on predicted Young modulus before and after immersion are better than the ones calculated for the unmodified mortar. Therefore, ACI 318 prediction model is recommended code for design and investigation works related to reparation mortars, screeds, pavements…etc. Also, it can be concluded that adding PET plastic aggregates by volume to blend Portland cement act to improve the corrosive resistance of this cement against MgSO4 aggressive medium

L’ENSEIGNEMENT A DISTANCE AU SEIN DES UNIVERSITES MAROCAINES : APPORTS, ENJEUX ET PERSPECTIVES

Depuis l’apparition du COVID-19, le mode d’enseignement en vigueur a connu un bouleversement radical passant des cours tenus en présentiel à des cours virtuels en vue d’assurer la continuité pédagogique. Ce changement de mode d’enseignement a connu un ensemble d’entraves dans sa mise en œuvre affaiblissant sa réussite notamment en termes d’efficacité d’apprentissage.A cet effet, il est opportun d’amorcer une réflexion sur ce sujet. Pour ce faire, cette recherche tente, d’une part, de mettre en évidence les concepts clés, les apports, les atouts et les handicaps de ce mode d’enseignement à distance, et d'autre part, d'exposer ses enjeux et ses préoccupations, plus particulièrement dans le contexte marocain

Neurogenic Myositis Ossificans of the Hip in a Patient with Axonal Polyneuropathy

Background. Neurogenic myositis ossificans is a rare entity defined by the development of soft tissue ossifications in patients with paraplegia or tetraplegia following neurological pathologies, often after cranial or spinal cord trauma. The diagnosis is based on imaging, in particular CT scan, which often reveals the presence of intramuscular ossifications of periarticular location. Treatment is based on analgesics, physiotherapy, and surgery as a last resort. Case Report. We present a case of neurogenic myositis ossificans in a 26-year-old patient followed for axonal polyneuropathy secondary to vitamin deficiency. Conclusions. Neurogenic myositis ossificans is a rare entity but is easily diagnosed, given the context of severe neurological disorders and the characteristic appearance on CT scan. In doubtful and atypical cases, a biopsy with histological study is recommended

Structural Characteristics of Composite Mortars and their Evolution with PET Substitution Level for Several Specimens’ Ages

This present study aims to investigate the evolution of structural response of PET-Mortar composite test with a short-beam specimen in three-point bending tests, with composite mortar ages and volumetric polymer rate and this, based on compression strength tests. The ultimate PET-mortar composite structural responses are calculated at the mid span of the short-beam by the mean of mechanics-of-materials theory basis. According to this theory, the distribution of bending moments and shear forces at any point of the composite short-beam specimen doesn’t depend on material mechanical properties especially the young modulus of modified mortar composite; so, the structural response analysis has been limited to investigate the evolution of ultimate deflection with several volumetric PET rates and composite mortar ages. In the other hand, we present a comparative study between experimental test results of splitting tensile and compressive strengths with the ones predicted by codale previsions (ACI-363 and B.S) codes in terms of PET mortar ages and volumetric PET rates in order to recommend the most suitable design code for PET-mortar composite applications in construction industries

Experimental analysis and optimization of mechanical properties of FDM-processed polylactic acid using Taguchi design of experiment

Fused deposition modeling (FDM) is one of the most used additive manufacturing processes in the current time. Predicting the impact of different 3D printing parameters on the quality of printed parts is one of the critical challenges facing researchers. The present paper aims to examine the effect of three FDM process parameters, namely deposition velocity, extrusion temperature, and raster orientation on the bending strength, stiffness, and deflection at break of polylactic acid (PLA) parts using Taguchi design of experiment technique. The results indicate that the temperature has the highest impact on the mechanical properties of PLA specimens followed by the velocity and the orientation. The optimum composition offering the best mechanical behavior was determined. The optimal predicted response was 159.78 N, 39.92 N/mm, and 12.55 mm for the bending strength, bending stiffness, and deflection at break, respectively. The R2 obtained from analysis of variance (ANOVA) showed good agreement between the experimental results and those predicted using a regression model