Water-in-oil emulsions generated by a microfluidic process : contribution to the study of the freezing of dispersed water

Ces travaux entrent dans la cadre du projet européen Fundamental and Applied Studies on Emulsion Stability (FASES). L'objectif de ce projet est de comprendre les phénomènes responsables de la déstabilisation des émulsions dans le temps, en relation avec les propriétés interfaciales de ces systèmes. Les travaux de thèse décrits dans ce mémoire se divisent en deux parties : ils portent tout d'abord sur la fabrication de gouttes d'émulsions eau-dans-huile par un procédé microfluidique, puis sur l'étude de la taille et de l'état de dispersion des gouttes sur la cristallisation de l'eau dispersée. Dans un premier temps, nous avons étudié les conditions opératoires permettant de fabriquer des gouttes de taille contrôlée par microfluidique avec le système de fluides mis en œuvre dans le projet FASES. Suivant le mode d'introduction des phases liquides, soit les débits, soit les pressions appliquées, ont été modifiés pour délimiter les zones de fabrication des gouttes. Afin de mieux comprendre les différences observées entre les deux modes d'introduction des fluides, un modèle reposant sur l'analogie entre circuits électriques et circuits microfluidiques a été proposé. Dans un second temps, les émulsions obtenues avec le dispositif microfluidique ont été analysées par calorimétrie et par thermo-microscopie. Les expériences ont permis de mettre en évidence, suivant les conditions étudiées (viscosité, taille des gouttes), différents processus de cristallisation des gouttes. Ces résultats mettent en avant directement le rôle du phénomène de sédimentation, les signaux de congélation observés dépendant fortement de l'état de dispersion des gouttes d'émulsion.This thesis takes place in the framework of the European project FASES (Fundamentaland Applied Studies on Emulsion Stability). The aim of this project is to understand the phenomena responsible for emulsions destabilization, in relation with the interfacial properties of these systems. The research work described in this thesis is divided into twoparts : the first part deals with the creation of water-in-oil emulsion droplets in a microfluidic device, and in the second part, the influence of the size and the state of dispersion of the droplets on the crystallization of dispersed water is analyzed.To begin with, the operating conditions required to create emulsion droplets by microfluidic were studied. Two modes of introduction of the liquid phases, based on flow and pressure-driven techniques, were used to create the droplets. Maps of the droplet formation regions were drawn as a function of the applied flow rates and pressures. In order to compare the two processes, a model based on the analogy between electrical and microfluidic circuits was proposed.Then, emulsions obtained with the microfluidic device were analyzed by calorimetry and thermo-microscopy. The experimental results evidenced different droplet crystallization processes, depending on the system parameters (oil phase viscosity, droplet size …). The water freezing signals strongly depend on the state of dispersion of the droplets, showing themajor role of droplet sedimentation in the emulsion destabilization process

A Comprehensive Analysis of the Dynamics and Transformations of West African Music Industries since Independence. A focus on Sénégal, Ghana, Nigeria & Mali.

This research paper presents a comprehensive analysis of West African music industries since Independence, specifically examining Sénégal, Ghana, Nigeria, and Mali. Through extensive research and interviews, this study explores the influences of globalization, colonial legacies, music genres, musicians\u27 political activism, government policies, recorded music market evolution, distribution systems, piracy, key industry players, the live sector, intellectual property environments, music promotion and media, and artist-led initiatives with an emphasis on education. The research aims to provide a holistic understanding of the West African music industries, shedding light on their historical, cultural, and socioeconomic dynamics. It contributes to scholarly discourse, serving as a valuable resource for researchers, scholars, and practitioners interested in West African music and its societal significance. This research holds relevance for policymakers, industry stakeholders, and professionals by informing decision-making, strategy formulation, and sustainable development efforts within the West African music ecosystem. It also highlights the relationship between music, politics, and social activism, and suggests strategies for a vibrant and sustainable music industry, emphasizing education, artist-led initiatives, and intellectual property protection.https://remix.berklee.edu/graduate-studies-global-entertainment-business/1337/thumbnail.jp

Differential scanning calorimetry analysis of W/O emulsions prepared by miniature scale magnetic agitation and microfluidics

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Water-in-oil droplet formation in a flow-focusing microsystem using pressure- and flow rate-driven pumps

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Relation entre stabilité des émulsions eau-dans-huile et cristallisation de gouttes d’eau générées par microfluidique.

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