Homogenization of cocoa beans fermentation to upgrade quality using an original improved fermenter

Cocoa beans (Theobroma cocoa L.) are the main components for chocolate manufacturing. The beans must be correctly fermented at first. Traditional process to perform the first fermentation (lactic fermentation) often consists in confining cacao beans using banana leaves or a fermentation basket, both of them leading to a poor product thermal insulation and to an inability to mix the product. Box fermenter reduces this loss by using a wood with large thickness (e>3cm), but mixing to homogenize the product is still hard to perform. Automatic fermenters are not rentable for most of producers. Heat (T>45°C) and acidity produced during the fermentation by microbiology activity of yeasts and bacteria are enabling the emergence of potential flavor and taste of future chocolate. In this study, a cylindro-rotative fermenter (FCR-V1) has been built and coconut fibers were used in its structure to confine heat. An axis of rotation (360°) has been integrated to facilitate the turning and homogenization of beans in the fermenter. This axis permits to put fermenter in a vertical position during the anaerobic alcoholic phase of fermentation, and horizontally during acetic phase to take advantage of the mid height filling. For circulation of air flow during turning in acetic phase, two woven rattan with grid have been made, one for the top and second for the bottom of the fermenter. In order to reduce air flow during acetic phase, two airtight covers are put on each grid cover. The efficiency of the turning by this kind of rotation, coupled with homogenization of the temperature, caused by the horizontal position in the acetic phase of the fermenter, contribute to having a good proportion of well-fermented beans (83.23%). In addition, beans'pH values ranged between 4.5 and 5.5. These values are ideal for enzymatic activity in the production of the aromatic compounds inside beans. The regularity of mass loss during all fermentation makes it possible to predict the drying surface corresponding to the amount being fermented. (Résumé d'auteur

En amont d’une approche culturelle de l’enseignement : le rapport à la culture

Au Québec, l’importance que les réformateurs accordent à l’approche culturelle de l’enseignement suscite plusieurs recherches. Peu de travaux, cependant, ont cherché à comprendre ce qui se trouve en amont de celle-ci, c’est-à-dire le rapport à la culture des enseignants. Ce texte présente le cadre théorique d’une définition du rapport à la culture que nous avons construit en nous inspirant des travaux de Charlot (1997) et des résultats d’une recherche menée auprès de 35 étudiants de deuxième année en enseignement du français. L’analyse de quatre idéaltypes du rapport à la culture nous amène à penser que le cadre théorique présenté ici constitue une avancée théorique et pratique pour penser la formation des enseignants au regard de l’approche culturelle de l’enseignement.The importance that those involved in curriculum reform in Quebec place on the cultural approach in teaching has led to several research projects. However, few of these have examined the origins of this notion, that is, the relation to the culture of teachers. This article presents the theoretical frame of a definition of the relation to culture that the authors have constructed. This is based on the works of Charlot (1997) and the results of research involving 35 second-year students in a French didactics course. An analysis of four ideal types of relation to culture led the authors to believe that the theoretical frame presented here is a promising direction both theoretically and practically for developing teacher training in terms of a cultural approach to teaching.En Quebec, la importancia que los reformadores otorgan al enfoque cultural de la enseñanza se encuentra al origen de varias investigaciones. Sin embargo, pocos trabajos intentaron entender lo que se encuentra por encima de este enfoque, es decir la relación a la cultura de los docentes. Este texto presenta el marco teórico de una definición de la relación a la cultura que hemos construido inspirándonos de los trabajos de Charlot (1997) y de los resultados de una investigación que se llevó a cabo con 35 estudiantes de segundo año en enseñanza del francés. El análisis de cuatro tipos ideales de relación a la cultura nos lleva a pensar que el marco teórico aquí presentado constituye un avance teórico y práctico para pensar la formación docente respecto al enfoque cultural de la enseñanza

Experimental Study of a natural ventilation strategy in a Full-Scale Enclosure Under Meteorological Conditions: A Buoyancy-Driven Approach

The performance of a natural ventilation strategy, in a full-scale enclosure under meteorological conditions is studied through an experimental study, a buoyancy-driven approach, by means of the estimation of the air exchange rate per hour and ventilation power. A theoretical and an empirical model are proposed based on the airflow theory in buildings and blower-door tests. A preliminary validation, by comparing our results with standards in air leakage rate determination, is made. The experimental study conducted here has shown that the natural ventilation strategy implemented reach promising air exchange rate levels, as they are rather high compared to other experimental studies found in the literature.  The proposed models have shown good potential and further analysis should take place. Also, other methods for validating these models should be implemented (for instants: CFD simulation or tracer gas methods), as the one in the standards is rather rough estimations.Keywords: Buoyancy-driven, natural ventilation, ventilation power, blower-door test, airflow in buildings

Caractérisation et valorisation de protections solaires pour la conception de bâtiments (analyse expérimentale et propositions de modélisations)

Lors d une démarche de modélisation énergétique d un bâtiment, la prise en compte de l enveloppe solaire reste souvent imprécise. L objet du travail présenté ici est la description détaillée de solutions de protections solaires, induisant un tirage thermique (bardage, store), dans un objectif de modélisation et de valorisation pour répondre aux besoins d industriels du secteur ; la caractérisation des performances permet alors d assister la maitrise d œuvre en phase conception.La mise en place d une plateforme expérimentale mur exposé sud muni d une protection solaire devant lame d air a permis la mesure de températures d airs et d éléments solides présents dans le système, de vitesses d écoulement dans la lame d air ouverte, et du flux radiatif incident. Deux types de bardage bois, un type de store et un type de métal déployé ont été considérés.Parallèlement, un modèle 1D amélioré de transfert de chaleur dans le système étudié est développé. Trois familles de modèle de convection dans la lame d air sont identifiées, présentées et intégrées dans le modèle global. La description de l écoulement dans la lame d air est retenue à partir d analyses des résultats expérimentaux.Un modèle simplifié d intégration de tels systèmes de protections solaires dans des plateformes de simulation thermique de bâtiments est proposé, basé sur la paramétrisation des sollicitations extérieures par le facteur solaire. La méthode de calcul du facteur solaire est présentée. Le caractère intrinsèque facteur solaire et son intérêt sont discutés notamment à partir d analyse de sensibilités.During the design process of a building, the energetic modelling of the solar envelop is often imprecise. The purpose of the present work is the detailed description of solar shading devices that induce a chimney effect such as claddings or blinds, which would allow their promotion in order to meet the industrial needs of the sector. An experimental platform south facing wall with a shading solar device that define an air gap has been set up and allow the measurement of temperatures, air flows in the ventilated air gap, and the incident solar radiation. Two different wooden claddings, one type of blinds and one type of expanded metal were considered.A 1D model has been developed by considering precisely the heat transfers in the system. Three families of convection model are identified, presented and integrated in the overall model. The description of the airflow in the air gap is chosen from analysis of the experimental results.A simplified model that allows the integration of such solar shading devices in a building simulation platform has been developed; it is based on the parameterization of external solicitations as function of the shading device properties. The calculation method of the solar factor is presented. The intrinsic nature of the solar factor is then discussed using sensibility analysis.BORDEAUX1-Bib.electronique (335229901) / SudocSudocFranceF

Indicateurs de durabilité pour la conception préliminaire de bureaux du point de vue énergétique

The building sector currently represents 40% of the energy consumption and one of the major emitters of greenhouse gases in the world. This, combined with the characteristic long lifespan of buildings, means that the decisions behind building design have long-term and multidimensional impacts on both society and the environment. As a result, there is a growing interest in the assessment of buildings based on the concept of sustainability, considering its three basic dimensions: economic, ecological and social. However, current evaluation systems are usually developed in the context of the declaration or certification of buildings, while only a limited number are designed to provide decision-support during the preliminary design phase. It is during these early design stages that key decisions such as construction principles and operation strategies are defined, usually with a limited amount of information available. In order to assist in decision-making during the preliminary building design, a set of indicators is proposed in this present work to evaluate early design alternatives by following a life-cycle analysis approach and according to the three pillars of sustainability. Indicator selection is based on consensus from the international projects and initiatives that compose the state of the art, as well as operational aspects such as database availability for calculation parameters, the evolution of information available and of specific design decisions at every stage of the design process. The conclusions of this study are focused on the energy design of commercial buildings, specifically offices, in the French context

Relation to Culture and Cultural Education on Students in High School French-as-a-First-Language Courses

To enhance the cultural content of the curriculum, several governments are increasing the presence of cultural education in schools. How do high school French-as-a-first-language teachers perceive this education? To answer this question, we relied on the relation to culture theoretical framework and analyzed 32 questionnaires answered by high school French-as-a-first-language teachers. Our results suggest that the teachers’ main role is to bring students to appreciate the cultural objects and practices associated with fine arts and literature and to develop their ability to distance themselves from their surroundings

Milieu poreux diphasique déformable : volume élémentaire représentatif déformable et prise de moyenne d'une équation de transport.

La modélisation du transport de masse, d'énergie et de quantité de mouvement dans un milieu poreux diphasique déformable requiert d'une part une connaissance détaillée à l'échelle du pore des phénomènes de transport concernés, et d'autre part une aptitude à moyenner ceux-ci sur un Volume Elémentaire Représentatif. Une démarche de prise de moyenne couramment utilisée repose sur une intégration des équations de transport local concernées sur un V.E.R. non-déformable, que le milieu soit déformable ou pas. De cette démarche résulte des équations de transport moyennées. L'objet du travail présenté ici consiste à moyenner, sur un VER déformable au cours du temps, une équation de transport simple : l'équation de conservation de la masse d'une phase dans un milieu diphasique. Cette démarche permet de mettre distinctement en évidence la non influence, sur la forme générale de l'équation moyennée obtenue, du caractère déformable du VER retenu

RNb-NeuS: Reflectance and Normal-based Multi-View 3D Reconstruction

This paper introduces a versatile paradigm for integrating multi-view reflectance (optional) and normal maps acquired through photometric stereo. Our approach employs a pixel-wise joint re-parameterization of reflectance and normal, considering them as a vector of radiances rendered under simulated, varying illumination. This re-parameterization enables the seamless integration of reflectance and normal maps as input data in neural volume rendering-based 3D reconstruction while preserving a single optimization objective. In contrast, recent multi-view photometric stereo (MVPS) methods depend on multiple, potentially conflicting objectives. Despite its apparent simplicity, our proposed approach outperforms state-of-the-art approaches in MVPS benchmarks across F-score, Chamfer distance, and mean angular error metrics. Notably, it significantly improves the detailed 3D reconstruction of areas with high curvature or low visibility.Comment: 14 pages, 13 figures, 7 tables. Accepted to CVPR 2024. The project page can be accessed via https://robinbruneau.github.io/publications/rnb_neus.html. The source code is available at https://github.com/bbrument/RNb-Neu

Analyse expérimentale et modélisation d’un échangeur-stockeur contenant des matériaux à changement de phase

Un outil de simulation dynamique a été développé afin d’étudier le comportement thermique d’un échangeur-stockeur contenant des matériaux à changement de phase dédié au rafraîchissement de l’air dans le bâtiment. Ce modèle prend en compte le phénomène de fonte par contact induit par la variation de densité entre les phases solide et liquide du MCP. Les résultats expérimentaux sont présentés et analysés afin de dégager le comportement dynamique de l’échangeur-stockeur soumis à un écoulement d’air à vitesse constante et à température d’entrée constant

Experimental Study of an Air-PCM Heat Exchanger: Melting in a Cylindrical Container

This paper presents experimental results of an air-PCM heat exchanger, with an in-line arrangement of cylindrical containers. The objective is to highlight the physical phenomena occurring in a single container during the phase change. Temperature and airflow measures were carried out. These values were used to find the heat exchanges on the container. The experimental heat values were compared and validated with the theoretical heat stored obtained from the material properties. An only conduction 1D radial model is proposed to describe the melting front in the container.Keywords: phase change materials, thermal storage unit, cylinder, latent heat, radial conduction