Optimisation et performance des bétons incorporant de la poudre de verre comme un remplacement partiel du ciment Portland

L'utilisation des ajouts cimentaires tel que, la fumée de silice, les cendres volantes et les laitiers est une activité courante au Canada en raison des conditions climatiques sévères. Au Québec, ces matériaux ne sont pas disponibles, ce qui implique leur transport sur des distances considérables. La poudre de verre est un matériau pouzzolanique fabriqué au Québec et présente ainsi l'avantage de remplacer partiellement ces matériaux cimentaires. Il est rapporté qu'un taux de remplacement partiel de 20% du ciment portland par la poudre de verre a des effets bénéfiques sur le développement des propriétés mécaniques et sur la durabilité du béton. Le taux d'incorporation optimal de la poudre de verre peut varier en fonction du rapport E/L, le dosage en liant et leur interaction. Il est difficile de déterminer l'effet de l'interaction entre lés paramètres de formulation sur les propriétés du béton par les méthodes conventionnelles. Alors, un plan factoriel composite à deux niveaux a été conçu pour déterminer l'effet des trois facteurs, ainsi que de leurs interactions sur les résistances en compression et la perméabilité aux ions chlore aux différents âges. Les facteurs modélisés dans ce plan factoriel sont; le rapport E/L, le taux d'incorporation de verre et le dosage en liant (kg/m [indice supérieur 3] ). Tous les modèles statistiques sont valides pour des rapports E/L entre 0,35 et 0,60, des pourcentages de la poudre de verre entre 10% et 40% et des dosages en liant entre 335 kg/m [indice supérieur 3] et 415 kg/m [indice supérieur 3]. Des mélanges de validation sont utilisés pour évaluer la fiabilité des modèles proposés. Le rapport entre les valeurs prédites et les valeurs mesurées se situe entre 0,83 et 1,15 ce qui indique une bonne fiabilité des modèles proposés. Le rapport E/L est le paramètre qui a le plus d'influence sur la résistance en compression à tous les âges et sur la perméabilité aux ions chlores à 28 jours. Par contre, le taux d'incorporation de la Poudre de verre a le plus d'influence sur la perméabilité aux ions chlore à 56, 91 et 180 jours grâce à la réactivité pouzzolanique de la poudre de verre. Des courbes iso-réponses sont établis pour comprendre l'évolution des propriétés du béton en fonction des différents paramètres de formulation. Elles montrent que l'incorporation de 20% de la poudre de verre aux bétons formulés avec un rapport E/L de 0,45 procure une perméabilité aux ions chlores inférieure à 1500 Coulombs à 56 jours. Cette valeur de perméabilité peut être obtenue à 56 jours en remplaçant 30% du ciment par la poudre de verre quelque soit le rapport E/L considéré. Une valeur de la résistance en compression à 28 jours de 35 MPa peut être obtenue en utilisant des bétons formulés avec un rapport E/L de 0,45 et incorporant 20% de poudre de verre. Cette valeur de la résistance à 28 jours peut être obtenue aussi avec des bétons formulés avec un rapport E/L de 0,42 et contenant 30% de poudre de verre. Des mélanges binaires et ternaires proportionnés avec un rapport E/L de 0,45 et incorporant de la poudre de verre affichent des bonnes propriétés mécaniques, ainsi que des bonnes caractéristiques de durabilité dans les milieux agressifs. Ces bétons développent des gains significatifs des propriétés mécaniques entre 28 et 91 jours. L'utilisation de la poudre de verre comme un ajout cimentaire alternatif présente une avenue très intéressante pour avoir des bétons durables et économiques

VIBE: The Practical Benefits of an Interactive E-Book for Art Education in Egypt

The Art Education subject in Middle school in Egypt has been somewhat neglected, without receiving adequate focus for its development in line with the modern demands of the current era. One of the primary sources of education for students in schools is textbooks. The existing school Art Education textbook lacks content, presentation, and design, requiring substantial improvement. The "Visual Interactive Book for Art Education” (VIBE) project aims to revolutionize the way Egyptian Art is taught in middle school classrooms. By transforming the content of the traditional Art Education textbook into an interactive electronic book, VIBE offers a more engaging, accessible, and effective learning tool for students seeking to develop their artistic sensibilities. VIBE showcases the works of renowned Egyptian artists and highlight their artistic techniques to enhance students' artistic abilities while improving accessibility and convenience for learning the material through expanded ways for communicating the knowledge. Through the incorporation of high-quality images, videos, and games, VIBE provides a dynamic and immersive learning experience.This paper offers a comparative analysis of the visual elements of the original printed textbook and VIBE to illustrate the research and design process. VIBE provides a better learning experience, accessible and intuitive design to navigate for middle school kids than the printed textbook. By leveraging cutting-edge technology and innovative design, VIBE offers a more engaging and effective learning tool for students to develop their artistic sensibilities and to foster cultural appreciation through art education topics. Plus, this solution costs less to produce and distribute, making it an easily adoptable solution for schools and educators to take on. Keywords: Art Education in Egypt, Interactive Learning, Gamification DOI: 10.7176/ADS/108-03 Publication date:October 31st 202

Static and dynamic responses of prestressed concrete beams with openings.

Web openings in beams occur quite often in practice to provide convenient passage of environmental services. As a result, storey heights in buildings can be reduced resulting in major cost savings. Some openings generally give rise to excessive deflections and stresses which have to be taken into consideration. In this research, a theoretical and experimental study is carried out to determine the influence of openings on the static and dynamic responses of prestressed concrete beams. The effect of openings on the behaviour of such beams at different stages of loading--transfer stage, working stage, and ultimate stage--as well as under excitation of dynamic load, is presented. The influence of opening dimensions, horizontal and vertical locations, type of cross section on the static behaviour is investigated from the stand point of deformations, stresses, cracking, and ultimate strength capacity. Also the effect of these parameters as well as the number and dimensions of continuous spans on the natural frequencies, mode shapes, stresses, and deformations is presented. The results from a non-linear finite element static analysis are substantiated by static test results from thirteen post-tensioned prestressed concrete beams, six of which were rectangular in section, five were T-, and two were of I-section. Also the results from a finite element dynamic analysis are substantiated by dynamic test results in the literature. Good agreement is shown between the theoretical and experimental results. Furthermore, an extensive parametric study is performed on prestressed beams with openings to: develop a design procedure against cracking of the opening chords; estimate the beam maximum deflection; find the distributing ratio of the shear force between the opening chords; obtain the ultimate capacity of prestressed beams with openings; and determine the natural frequencies, and hence the dynamic response of simply supported and continuous prestressed beams with openings.Dept. of Civil and Environmental Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1993 .A333. Source: Dissertation Abstracts International, Volume: 54-09, Section: B, page: 4817. Adviser: J. B. Kennedy. Thesis (Ph.D.)--University of Windsor (Canada), 1993

Micro hydraulic turbine for power generation in micro scale channels

Micro hydrokinetic energy scheme presents an attractive, environmentally friendly and efficient electric generation in rural, remote and hilly areas. However, this scheme is yet to be fully discovered, as researchers are still searching for solution for the main problems of low velocity of current in the open flow channels and low efficiency of hydrokinetic turbines. This research proposes a novel system configuration to capture as much as kinetic energy from stream water current. Deploying acceleration nozzle in channels is a unique solution for increasing the efficiency of channels’ current flow systems while the use of micro hydraulic cross flow turbine (CFT)/ Banki turbine is the most proper and practical solution. This system, known as bidirectional diffuser augmented (BDA) channel, functions by utilizing dual directed nozzles in the flow, and surrounded by dual cross flow/ Banki turbines. In this study, numerical and experimental investigations were carried out to study the flow field characteristics of the new system approach with and without turbines. A numerical investigation was carried out in this research work using finite volume Reynolds-Averaged Navier-Stokes Equations (RANSE) code ANSYS CFX and Fluent. Validation was carried out by using experiments, with and without turbines. The flow characteristics through channel and the performance of the twin (lower and upper) cross flow turbines were studied, and it was found that the water flow speed had been significantly enhanced due to the current BDA system in which the speed of the flow was increased by 400%. The maximum efficiency of the overall system with two turbines was nearly 55.7%. The efficiency was relatively low compared to hydraulic turbine efficiency, however, this can be considered very good in view that head available to the present system was very low. The use of this system will contribute towards a more efficient utilization of flows in rivers and channels for electrical generation in rural areas

Thermal performance of the chilled water spirally coiled finned tube in cross flow for air conditioning applications

AbstractThe thermal performance of spirally coiled finned tube in cross flow was investigated experimentally. The effects of curvature ratio, flow direction, fin pitch and flow rate of chilled water and air on thermal characteristics of spirally coiled finned tube have been studied. Six test sections with curvature ratios of 0.027, 0.03, 0.04, tube pitches of 18, 20, 30mm, and fin pitches of 33, 22, 11mm were used. The experiments were done using a pilot wind tunnel with air Reynolds number range 35,500–245,000. Innermost and outermost flow directions of chilled water with Reynolds number range 5700–25,300 have been investigated. The innermost flow direction has significant enhancement effect on the Nusselt number compared with outermost flow direction. The decrease of fin pitch enhances the Nusselt number on expense of pressure drop. Decreasing the curvature ratio increases air side Nusselt number on expense of pressure drop. A set of empirical expressions for predicting the friction factor and the Nusselt number for air flow across the spiral coils have been regressed based on the obtained data in the present experiments