Experimental Analysis of the Physical Degradation of Polymers – The Case of Polymethyl Methacrylate

Polymers are known to be sensitive to aging; their lifetime can be predicted through experimental tests. The present paper presents an experimental study on the long-term performance of polymethyl methacrylate (PMMA) exposed to solar and UV radiations, drinking water and sea water. The performance of this polymer was analyzed in terms of strain variation, strain at break in tension, and Young's modulus. The results obtained showed that the amount of absorbed water is independent of the nature of the solvent, and only the absorption kinetics may be regulated by the species contained in the medium. This seems to indicate that plastification of polymers is a reversible phenomenon. In addition, it was found that the tensile strength and elastic modulus drop with increasing immersion time. Compared with seawater, the absorption of drinking tap water, after 36 months, leads to a non-linear behavior of the polymethyl methacrylate. Exposition of  PMMA to UV radiation and global solar radiation, for the same duration of exposure, resulted in greater performance degradation when the polymer was exposed to UV radiation. In addition, the results obtained after a 19-month exposure period that the UV radiation changes the behavior of this material from viscoelastic to viscoplastic.  &nbsp

LA DIGITALISATION AU SERVICE DES TOURISTES : LA QUETE D’UN AVANTAGE COLLABORATIF

L’évolution du concept de la co-création cristallise les différentes mutations théoriques et pratiques dans la pensée marketing. La digitalisation a considérablement contribué à ce changement et a de ce fait, métamorphosé la création classique de la valeur. L’objectif de cette recherche est donc d’analyser en profondeur l’environnement Digital qui sert d’antécédent à la Co-création d’expérience dans le secteur touristique. Le présent travail s’intéresse également à la compréhension du rôle de cette co-création dans l’amélioration du bien-être des touristes.Une investigation empirique a été menée en administrant un questionnaire auprès des touristes qui ont séjourné dans des Hôtels-Clubs, dans deux grandes destinations touristiques au Maroc à savoir, la région de Tanger-Téouan et la région de Marrakech.Les résultats obtenus via une modélisation par équations structurelles, montrent l’effet direct et positif de l’environnement Digital sur le degré de la Co-création de l’expérience touristique. L’étude fait valoir également, que le bien-être est une conséquence significative de la co-création de l’expérience touristique.Enfin, une relation positive et significative a été confirmée entre l’environnement Digital et le bien-être des touristes. The evolving concept of co-creation embodies the various theoretical and practical shifts within the marketing thinking. Digitalization has significantly contributed to this change and thus, transformed the classical concept of value creation.This research aims at analyzing in depth the digital environment that serves as an antecedent for the experience Co-creation in the tourism field. This study also focuses on understanding the role of co-creation in enhancing tourist’s well-being. An empirical investigation was conducted through a questionnaire administered to tourists who stayed at Club hotels, in two main tourism destinations in Morocco, namely, the Tangier-Teouan region and the Marrakech region.The findings, obtained through structural equation modeling, show the direct and positive influence of the Digital environment on the degree of the tourist experience co-creation.The study also confirm that well-being is a significant consequence of the tourist experience co-creation.At the end, a positive and significant relationship was also confirmed between the digital environment and the tourist’s well-being