Optimization of Particle Size Distribution of Concrete Aggregates

This paper investigates the optimization of concrete aggregate particle size distribution under a dense arrangement of a group of sphere particles with maximum diameter of 25 m. The proposed sphere model reflects the particles that constitute 'aggregate' in concrete. In scope of this, the volume proportions on some regular close-packed arrays of spheres, such as face center cubic (FCC) lattice packing will be discussed. Such space filling between this regular crystalline system is taken into consideration as it suggests a regular arrangement and the possibility to attain a dense mixture of different aggregate sizes is considerable. The main objective is to compare the generated particle size distribution and its corresponding density with those proposed by European standards, referring EN 933-2 and EN 1097-3. The concept of gradation, compacted density, packing and Fuller distribution are also discussed

EXPÉRIMENTATIONS VIRTUELLES: VIE ARTIFICIELLE POUR LA GÉNÉRATION DE FORMES ET DE COMPORTEMENT

National audienceCet article présente une sélection de travaux réalisés par l'équipe VORTEX de l'IRIT depuis 1993 dans les domaines de la génération automatique de formes et de comportements. Nous montrons ici la spécificité de ces travaux utilisant des techniques originales issues de la vie artificielle afin de proposer un nouveau type d'interaction entre l'utilisateur et l'environnement de simulation

Recycling Of Ferrochromium Industrial Wastes in Albania as Coarse Aggregate, in Road Base Construction and in Concrete

This study investigates the possibility of recycling the ferrochromium industrial wastesin the Mat region of Albania by introducing it as a substitute for conventional coarseaggregate, in road base construction and in concrete. The chemical composition and aggregateabrasion resistance tests were carried out for ferrochromium slag (FCS). Moreover thecompressive strength of concrete with FCS as coarse aggregate was investigated. The resultswere compared with those carried out with natural river aggregates (NRA) and crushed riveraggregate (CRA). Based on the results the abrasion resistance of FCS was (25% mass loss inthe Los Angeles abrasion test) the highest compared to those of the conventional specimens.The compressive strength of concrete produced with FCS was 24% higher than that of CRAspecimen. The data acquired from the tests showed that FCS could be conveniently used ascoarse aggregate in road base construction and higher compressive strength concretes

Analyzing Transport Problems in Tirana on a Sound Scientific System Base

The globalization process taking place recent years has significantly increased the need for mobility. Due to the urban population growth and urbanization, the role of transportation engineering in daily life has mainly increased accompanied by the challenges featuring it. Of importance is the mobility on urban areas, considering the socio-economic and environmental effects. Furthermore in developing countries to such situations contribute the weak enforcement of traffic rules and regulations. This study illustrate, analyze and provides new methodologies on optimizing traffic congestion in the capital of Albania, Tirana. Focusing on the road network and public transportation impacts on mobility, the research seeks to outline new strategic solutions for the rapid developing capital, oriented toward society wealth as follows; i) The investigation and illustration of the strengths, weakness and improvements that could be implemented on road network and reorganization inside the urban area of the capital is of first call. ii) As the main motorized transportation mode, reorientation and coordination of public transport system directly affect the socio-economic behavior and smoother traffic flow. iii) The lack of coherent data concerning traffic information system in problematic bottlenecks directly affect traffic management in those zones. In this context, implementation of different techniques for data gathering and application of intelligent transportation system in particular areas like CBD, improves the management of the congestion. Beside, reassessment of the existing and implementation of new parking areas due to future requirements, efficiently smoothers unpredicted congestion situations. iv) Last but not list, the establishment of a framework for actions for the road network and public transportation systems of Tirana results in provision of successive recommendations and analysis. Moreover it shall evaluate the relationship and impact that and public transportation system have on each other and their effect to socio-economic development and environmental issues of the capital

Diachronic Growth of the Historical Urban Fabric of Tirana. - Typology of the “Multi-Familiar Dwelling Under the Same Roof”, As a Base Unit of this Urban Structure.

Nowadays the historical area of Tirana is in danger of extinction, not only due to the economic and cultural diversity of its habitants, but mostly of the careless approach of planning on such historical urban areas. The further study will explain the urban and historical values of the urban territory trough the study of diachronic development of the urban tissue and its base unit structure, in order to better comprehend and highlight the territorial potentials of the historical area. The historical urban fabric of Tirana, as many a like structures, is formed under a stratification process. Process that shaped and gives identity to such urban structures and the way these structures are created and develop makes them unique, as unique as a finger print. These features gives identity to such built areas creating a sense of belonging, creating mutual relationship between the people, the territory and define social behaviour and way of living. The typical “Multi-familiar dwelling under the same roof of Tirana” with all factors, against, had evolve in a sustainable way in the territory where it was located, creating a suitable way of living and influenced the new buildings with its characteristics. This typology creates an urban “status quo” and as a result of that we have a large part of the territory and its characteristics, preserved, the most important of them, the red pattern created by the roofs. These roofs seem very disordered but in fact they organize an even more complicated situation under their cover, making possible the unification of different social models

Hybrid client-server and P2P network for web-based collaborative 3D design

National audienceOur proposed research project is to enable 3D distributed visualization and manipulation involving collaborative effort through the use of web-based technologies. Our project resulted from a wide collaborative application research fields: Computer Aided Design (CAD), Building Information Modeling (BIM) or Product Life Cycle Management (PLM) where design tasks are often performed in teams and need a fluent communication system. The system allows distributed remote assembling in 3D scenes with real-time updates for the users. This paper covers this feature using hybrid networking solution: a client-server architecture (REST) for 3D rendering (WebGL) and data persistence (NoSQL) associated to an automatically built peer-to-peer (P2P) mesh for real-time communication between the clients (WebRTC). The approach is demonstrated through the development of a web-platform prototype focusing on the easy manipulation, fine rendering and light update messages for all participating users. We provide an architecture and a prototype to enable users to design in 3D together in real time with the benefits of web based online collaboration

MOOC Avion : une diffusion massive de l’expertise ISAE-SUPAERO

Le numérique révolutionne la façon de travailler, de collaborer, de communiquer ; il devait nécessairement transformer en profondeur la manière d’enseigner. L’ISAE-SUPAERO, acteur majeur du domaine de la formation aéronautique et spatiale au niveau national et international, accorde une place importante à l’innovation pédagogique pour l’ensemble des formations proposées. Dans ce contexte, le numérique constitue une opportunité permettant de diversifier les méthodes d’apprentissage utilisées dans les différentes formations ainsi que de former les étudiants à un usage professionnel de ces outils. L’essor des MOOCs au sein de l'établissement redessine peu à peu l’accès à la connaissance aéronautique et spatiale, pour qu'au-delà de nos propres étudiants, les salariés, les futurs étudiants et tous les passionnés d’aéronautique et d’espace puissent bénéficier du savoir-faire et de l'expertise de l'ISAE-SUPAERO. Pour son premier MOOC, l’ISAE-SUPAERO a décidé de poser la question simple et universelle : « Comment vole un avion ? » et d’y répondre par le « MOOC-Avion : introduction à la mécanique du vol ». Cet article propose un retour d’expérience sur la réalisation et la mise en œuvre de ce projet