Micromorphological description of vernacular cob process and comparison with rammed earth

International audiencePast builders have developed very low-embodied energy construction techniques optimizing the use of local building materials. These techniques are a source of inspiration for modern sustainable building. Unfortunately, this know-how was orally transmitted andwas lost as earth construction fell into disuse during the 20th century in European countries.The absence of written documents makes necessary to use an archaeological approach in orderto rediscover these construction strategies. Micromorphological analysis of thin sections collected in earth building walls was used for the first time to describe cob construction tech-nique and highlighted several typical pedofeatures allowing to clearly identifying this process.Finally, a first comparison of the cob and rammed earth micromorphological features permitted to identify two key factors to distinguish these two techniques, the manufacturing state (solid or plastic) and the organization of the material in the wall

Le développement de la filière biomasse énergie en Guyane : Quelle articulation entre développement soutenable, économie verte et politique de promotion rurale ?

International audienceLe développement agricole fondé sur la biomasse énergie est exemplaire de l'articulation des enjeux économique, sociaux, des questions de soutenabilité et du défi de mise en œuvre des politiques énergie/climat dans les territoires. A partir du cas d'un projet finalisé en Guyane nous menons une analyse combinant deux aspects : d'une part une étude de la construction de la filière en fonction des ressources du territoire. D'autre part nous tentons d'identifier et d'évaluer les modes d'interventions des acteurs, selon leur nature à différents stades du processus projet. Finalement nous tentons de caractériser les éléments décisifs pour la soutenabilité de la filière qui permettraient l'essor d'une « économie verte ». Cette recherche s'appuie sur des données recueillies au cours des trois dernières années en Guyane, ainsi que sur un cadre analytique construit dans un projet de master

Bringing Semantic Services to Real World Objects

The last few years have seen the emergence of two parallel trends: the first of such trends is set by technologies such as Near Field Communication, 2D Bar codes and RFID that support the association of digital information with virtually every object. By using these technologies, ordinary objects such as coffee mugs or advertisement posters provide digital information that can be easily processed. The second trend is set by (semantic) Web services that provide a way to automatically invoke functionalities across the Internet lowering interoperability barriers. The PERCI system, discussed in the article, provides a bridge between these two technologies allowing the invocation of Web services using the information gathered from the tags to effectively transform every object in a service proxy.</p

Comparing Techniques for Mobile Interaction with Objects from the Real World.

Mobile interaction with objects from the real world is gaining in popularity and importance as different mobile technologies increasingly provide the basis for the extraction and usage of information from physical objects. So far, Physical Mobile Interaction is used in rather simple ways. This paper presents a comparison and evaluation of more complex and sophisticated techniques for Physical Mobile Interaction. The results indicate the importance of usability guidelines that pay attention to these new interaction techniques

Identifying Protein Function—A Call for Community Action

Functional information is lacking for many of the hypothetical proteins encoded within sequenced genomes. Richard Roberts proposes that a community-based approach might offer an effecient way to fill the function ga

Un exemple de réhabilitation de site : la végétalisation du terril de Péchiney aux Baux-de-Provence

International audienc

An acute coronary syndrome in Antarctica

Cruise tourism to Antarctica is constantly growing. Passengers and crewmembers may experience illnesses or injuries while traveling to remote areas with harsh weather conditions from where prompt evacuation is mostly unavailable. While a small explorer ship was at Wilhelmina bay (64°39’ South and 62°08’ West) in the Antarctic Peninsula, a 73-year-old male passenger presented with acute chest pain after two short excursions off the vessel in cold weather conditions. He was treated on board and remained clinically stable until the ship reached Ushuaia at the end of the cruise which was 5 days after the symptoms onset.

Caracterización experimental de la focalización en un cristal de sonido 3D

En un medio continuo e isótropo, una onda acústica se propaga de manera omnidireccional. Sin embargo, para algunas aplicaciones, puede ser útil restringir la difusión de una señal sonora dentro de un espacio finito. Los cristales de sonido son estructuras periódicas, qué, con ciertos materiales y geometría, presentan propiedades interesantes como las bandas prohibidas (rango de frecuencias no transmitidas a través el cristal) o la focalización del sonido (como las lentes convergentes en óptica). El objeto de este proyecto es hacer un estudio experimental cualitativo completo de la focalización de un nuevo cristal de sonido tridimensional en el rango ultrasónico. Este estudio se basa en las simulaciones efectuadas por los miembros del laboratorio, las cuales nos permiten concentrarnos en una banda de frecuencia estrecha, de 150 a 230 kHz, que corresponde al final de la primera banda del cristal. Después de haber verificado la focalización en esta banda del cristal, determinamos experimentalmente las frecuencias correspondientes al band gap, para poder a continuación, estudiar la influencia de la separación entre el cristal y la fuente de emisión. A fin de obtener resultados los mas fieles posibles y con menos incertidumbres, optimizamos el sistema de medida, haciendo unos experimentos previos (estudio de la alineación, de las reflexiones, etc.). Al final, los resultados del experimento concuerdan con la teoría, la focalización esta demostrada y permiten tener una buena base para posibles trabajos futuros.In an isotropic and continuous medium, an acoustic wave propagates in an omnidirectional way. However, it should be useful to restrict the diffusion of the sound signal in a finite space, for particular applications. Sound crystals are periodic structures that have interesting properties, depending on their geometry and material, like band-gap (frequency range does not transmit by the crystal), or sound focalisation (as convergent lens in optic). The aim of this project is making a full qualitative experimental study of focalisation for a brand new three-dimensional sound crystal, in the ultrasonic range. This work is based on previous simulations made by the laboratory staff that permit to be concentrated in a limited frequency range, from 150 until 230 kHz, which tally with the end of the first band gap. Once focalisation in this crystal gap checked, we determine experimentally frequencies corresponding to the band gap, and then, we study the influence of the distance between crystal and emission source. In order to get accurate results and reduce uncertainty of measurement, we optimize system of measurement, making previous experiments (crystal alignment, reflexions, etc.). Finally, results of experiment tally with theory, focalisation has been proved and it makes it possible having a great base to possible future workHamard, S. (2013). Caracterización experimental de la focalización en un cristal de sonido 3D. Universitat Politècnica de València. http://hdl.handle.net/10251/29018Archivo delegad

Cob, a vernacular earth construction process in the context of modern sustainable building

The will of reducing environmental and social impact of building industry has led to a renewed interest in earth construction. Most of earth construction literature dealt with rammed earth or adobe techniques, but very little with cob. Yet, cob participates in the diversity of vernacular earth construction processes that value local materials and is an alternative to rammed earth and adobe in specific geographical conditions. Conservation of cob heritage also requires a better knowledge of this vernacular construction process. This bibliographical analysis gathered extensive data on cob process and summarized the different cob process variations, attempting to take into account their diversity. This analysis allowed us to provide novel data on cob process, and more specifically, (1) a clear definition of cob with regard to other earth construction processes, (2) a first summarized description of cob process that clearly distinguished its variations, (3) a list of fibres traditionally employed, (4) values and, if possible, average and standard deviation for fibre length, fibre content, manufacture water content, drying times, lift heights and wall thicknesses, (5) a summary of the strategies to manage shrinkage cracks, (6) a criterion on the quality of implementation and/or earth for cob, based on slenderness ration of lifts and (7) a discussion on the evolution of cob process with regard to societal evolutions