Développement d’une ACV conséquentielle dynamique : augmentation de la pénétration du bois dans le secteur de la construction

La fabrication des produits en bois peut avoir un impact plus faible sur le changement climatique que d'autres matériaux de construction, et leur teneur en carbone peut faire des bâtiments un puits de carbone temporaire. Les avancées technologiques, la formation, et la synergie qui se mettent en place entre les acteurs industriels et institutionnels participent aussi à l’acceptation du bois dans les bâtiments. Avec le nombre croissant de publications montrant que l'utilisation du bois dans la construction peut être une option écologique, les décideurs pourraient s'orienter vers une utilisation à grande échelle. Cependant, l'utilisation à grande échelle des produits du bois dans les bâtiments nécessite une meilleure compréhension de ses conséquences pour soutenir les politiques de lutte contre le changement climatique (CC). C’est pourquoi un cadre d'évaluation de l’utilisation croissante du bois dans la construction est développé dans cette thèse. Il se fonde sur une modélisation prospective d’analyse des flux de matière (AFM) pour supporter la méthode d’analyse du cycle de vie (ACV). Le secteur de la construction non résidentielle (NR) en bois au Québec est un bon exemple car les gouvernements (provincial et fédéral) cherchent à l’accroitre. En 2008, l’industrie forestière subit une crise suite à la baisse de ses exportations. Puis, à la suite de stratégies successives, le gouvernement québécois propose la première version de la charte du bois en 2013. Elle représente son engagement à augmenter l’utilisation du bois dans la construction pour soutenir l’industrie forestière et de la construction, ainsi que pour réduire les émissions de gaz à effet de serre (GES). Les bâtiments résidentiels unifamiliaux étant majoritairement faits en bois, l’engagement vise la construction non résidentielle et multifamiliale. Les ACV sur le bois ont des lacunes qui limitent la représentation et l’analyser des conséquences de son utilisation croissante à l’échelle d’une région pour un stock de bâtiment. Premièrement, la littérature suggère que la substitution de matériaux de construction conventionnels par des produits en bois est souhaitable pour atténuer les émissions de GES. Elle présente la différence de l’impact au CC qui est attribuable à la comparaison de deux bâtiments, structures, ou produits. Les autres impacts environnementaux sont moins abordés. Le résultat d’une évaluation à l’échelle d'une structure spécifique ou d’un bâtiment est difficilement applicable à d’autres cas d’études ou extrapolable à l’échelle d’une région pour un stock de bâtiments hétérogènes. De plus, ces évaluations ne permettent pas de considérer l’impact des processus impliqués ou évités en conséquence de cette substitution. L’identification de ces processus est un défi en ACV conséquentielle (ACV-C). Enfin, une utilisation du bois à grande échelle implique de comprendre le niveau de récolte par rapport disponibilité de la ressource, mais la quantification des flux de matière dans le secteur du bâtiment est limitée aux bâtiments résidentiels en raison d’un manque de données pour les bâtiments NR. Dans le but d’améliorer l’évaluation des impacts environnementaux causés par une augmentation de l’utilisation du bois dans la construction, la réponse aux lacunes est organisée de la façon suivante. Premièrement, des paramètres ont dû être élaboré pour estimer et projeter l’utilisation du bois dans les structures NR. Cette estimation sert de flux de référence. Elle est intégrée dans une AFM pour comprendre l’importance de ses valeurs extrêmes par rapport à la récolte totale du bois et la limite de la ressource disponible. Des facteurs de substitution de matières ont été créés à partir de différentes structures de la littérature. Ils sont appliqués à la quantité estimée des produits en bois qui sont utilisés. Enfin, la modélisation dynamique de la croissance des arbres et du roulement de stock permet de créer une cohérence temporelle entre l’inventaire des flux élémentaires et la caractérisation dynamique de l’impact. Ce projet de recherche apporte plusieurs contributions. Il permet d’estimer l’utilisation croissante du bois dans la construction NR à l’échelle d’une région. Ce type d’estimation est utile pour l’inventaire des flux de référence d’une ACV et pour compléter une AFM. Intégrée dans une AFM, elle permet de supporter l’identification de ressources contraintes dans le cas d’une ACV-C. Ce projet propose également des facteurs de substitution fonctionnelle pour le bois de structure par rapport à une combinaison de l’acier et du béton. Ils sont applicables pour les ACV-C et leur variabilité permet de considérer différentes structures et un intervalle d’impact déplacé pour tous les indicateurs environnementaux afin de faciliter l'interprétation d’une extrapolation à grande échelle. Enfin, le projet met en évidence l’importance relative entre la substitution, les stratégies de fin de vie, et la séquestration temporaire du carbone. Pour une cohorte de bâtiments, le stockage du carbone dans celle-ci est temporel pendant sa durée de vie. Cependant, à la dimension de cohortes successives, le stockage du carbone est plus durable dans le temps, soit pendant la durée de vie du stock. Le cumul du forçage radiatif n’était pas étudié à cette échelle dans le cas d’une régénération forestière après la récolte. Au Canada, la gestion de la forêt se base sur la possibilité annuelle de coupe qui est déterminée par les gouvernements provinciaux pour s'assurer que les taux de récolte demeurent à des niveaux durables. Cette possibilité forestière traduit le mètre cube de bois disponible pour la récolte. L'AFM a permis de montrer l’importance de l’estimation maximale du volume récolté pour les nouvelles structures par rapport à la possibilité forestière et à l’évolution de la récolte pour les exportations et de la récolte totale. Plus de recherche empirique est nécessaire sur l’analyse des flux du bois des autres marchés. La modélisation de la substitution a permis d'évaluer non seulement le déplacement d'impact sur le CC, mais aussi sur la santé humaine, la qualité des écosystèmes et les ressources. Les stratégies et politiques qui répondent à l'urgence climatique devraient également prêter attention à la qualité des écosystèmes. Dans le scénario de substitution minimale, le bois évite peu d’acier et de béton. De plus, la production unitaire des grades d’acier et de béton utilisés provoque moins d’impacts que celle des grades utilisés dans les scénarios de substitution moyenne et maximale. Dans ce scénario minimum, c’est la séquestration du carbone qui permet un évitement de l’impact sur le CC. A l’échelle de la structure, le maintien de cet évitement au cours du temps dépendant de la fin de vie de celle-ci. A l’échelle du stock de structure, le maintien de l’évitement dépend de son renouvellement et de la fin de vie des structures. Enfin, utiliser un facteur de caractérisation statique pour le CC pour un inventaire dynamique conséquentielle peut conduire à des conclusions opposées à celles d’un facteur dynamique. Finalement, différentes pistes d’amélioration sont présentées. En effet, des limites subsistent au niveau de la modélisation ACV et AFM en matière de complétude et de qualité des données ainsi qu’au niveau de la complexité des méthodes d’inventaires et d’impacts dynamiques. Par exemple, la méthode présentée pour estimer la quantité de bois pourrait être comparée à d’autres méthodes, si des données sont disponibles. Une plus grande désagrégation entre les différents produits du bois et leurs secteurs est nécessaire pour mieux cibler les conséquences potentielles de leurs complémentarités, concurrences et dynamiques de marché. Une modélisation plus complète des cycles de carbone forestier permettrait de comprendre si la récolte peut éviter les émissions de carbone dues aux feux et autres causes de mortalité des arbres. Enfin, l’impact sur la qualité des écosystèmes devrait être plus abordé par le sujet de la construction en bois.Abstract : The manufacture of wood products can have a lower impact on climate change than other building materials, and their carbon content can make buildings a temporary carbon sink. Technological advances, training, and synergy between industry and institutional players are also contributing to the acceptance of wood in buildings. With the increasing number of publications showing that the use of wood in construction can be an environmentally friendly option, decision-makers may be moving towards large-scale use. However, the large-scale use of wood products in buildings requires a better understanding of its consequences to support climate change (CC) policies. Therefore, a framework for assessing the increasing use of wood in construction is developed in this thesis. It is based on a prospective material flow analysis (MFA) modelling to support the life cycle assessment (LCA). The non-residential (NR) wood construction sector in Quebec is a good example as the provincial and federal governments seek to expand it. In 2008, the forestry industry suffered a crisis due to a decline in exports. Then, following successive strategies, the government of Quebec proposed the first version of the Wood Charter in 2013. It represents its commitment to increase the use of wood in construction to support the forestry and construction industry, as well as to reduce greenhouse gas (GHG) emissions. As single-family residential buildings are predominantly made of wood, the commitment is aimed at non-residential and multi-family construction. LCAs on wood have shortcomings that do not allow them to represent and analyze the consequences of its increasing use on a regional scale for a building stock. Firstly, the literature suggests that substitution of conventional building materials with wood products is desirable to mitigate GHG emissions. It presents the difference in CC impact that is attributable to the comparison of two buildings, structures, or products. Other environmental impacts are less discussed. The result of an assessment at the scale of a specific structure or building is hardly applicable to other study cases or extrapolable to the scale of a region for a heterogeneous building stock. Furthermore, these assessments do not allow for the impact of the processes involved or avoided as a result of this substitution to be considered. The identification of these processes is a challenge in consequential LCA (C-LCA). Finally, large-scale use of wood implies understanding the level of harvesting versus availability of the resource, but the quantification of material flows in the building sector is limited to residential buildings due to a lack of data for NR buildings. In order to improve the assessment of the environmental impacts caused by an increase in the use of wood in construction, the response to the gaps is organized as follows. Firstly, parameters had to be developed to estimate and project the use of wood in NR structures. This estimate serves as a reference flow. It is integrated into an MFA to understand the importance of its extreme values in relation to the total wood harvest and the limit of the available resource. Material substitution factors have been created from different structures in the literature. They are applied to the amount of wood products used. Finally, dynamic modelling of tree growth and stock turnover allows for temporal consistency between the inventory of elementary flows and the dynamic characterization of the impact. This research project makes several contributions. It allows to estimate the increasing use of wood in NR construction on a regional scale. This type of estimation is useful for the inventory of reference flows in an LCA and for completing an MFA. When integrated into an MFA, it supports the identification of constrained resources in the case of a C-LCA. This project also proposes functional substitution factors for structural wood compared to a combination of steel and concrete. They are applicable for C-LCA and their variability allows to consider different structures and a displaced impact range for all environmental indicators in order to facilitate the interpretation of a large scale extrapolation. Finally, the project highlights the relative importance between substitution, end-of-life strategies, and temporary carbon sequestration. For a cohort of buildings, carbon storage in the cohort is temporal during its lifetime. However, at the scale of successive cohorts, carbon storage is more lasting, i.e. over the lifetime of the stock. Cumulative radiative forcing was not studied at this scale in the case of post-harvest regrowth. In Canada, forest management is based on the annual allowable cut which is determined by provincial governments to ensure that harvest rates remain at sustainable levels. This allowable cut reflects the cubic meter of wood available for harvesting. The MFA showed the importance of the maximum estimation of the harvested volume for new structures regarding the allowable cut and changes in harvesting for exports and total harvesting. More empirical research is needed on the analysis of wood flows from other markets. Substitution modelling allowed to assess not only the displacement of CC impacts, but also human health, ecosystem quality and resources. Strategies and policies that respond to the climate emergency should also pay attention to ecosystem quality. In the minimum substitution scenario, wood avoids little steel and concrete. In addition, the unit production of the steel and concrete grades used causes fewer impacts than the that of the grades used in the average and maximum substitution scenarios. In this minimum scenario, it is carbon sequestration that enables CC impact avoidance. At the scale of the structure, the maintenance of this avoidance over time depends on the end of life of the structure. At the scale of the structure stock, the maintenance of the avoidance depends on its renewal and the end of life of the structures. Finally, using a static characterization factor for CC with a dynamic consequential inventory can lead to opposite conclusions to a dynamic factor. Finally, various avenues for improvement are presented. Indeed, limitations remain in LCA and MFA modelling in terms of data completeness and quality, as well as in the complexity of dynamic impact and inventory methods. For example, the presented method for estimating the amount of wood could be compared to other methods, if data are available. A greater disaggregation between the different wood products and their sectors is necessary to better target the potential consequences of their complementarities, competitions and market dynamics. More comprehensive modeling of forest carbon cycles would help understand whether harvesting can avoid carbon emissions from fires and other causes of tree mortality. Finally, the impact on the quality of ecosystems should be addressed more by the subject of wood construction

Towards a self-consistent orbital evolution for EMRIs

We intend to develop part of the theoretical tools needed for the detection of gravitational waves coming from the capture of a compact object, 1-100 solar masses, by a Supermassive Black Hole, up to a 10 billion solar masses, located at the centre of most galaxies. The analysis of the accretion activity unveils the star population around the galactic nuclei, and tests the physics of black holes and general relativity. The captured small mass is considered a probe of the gravitational field of the massive body, allowing a precise measurement of the particle motion up to the final absorption. The knowledge of the gravitational signal, strongly affected by the self-force - the orbital displacement due to the captured mass and the emitted radiation - is imperative for a successful detection. The results include a strategy for wave equations with a singular source term for all type of orbits. We are now tackling the evolution problem, first for radial fall in Regge- Wheeler gauge, and later for generic orbits in the harmonic or de Donder gauge for Schwarzschild-Droste black holes. In the Extreme Mass Ratio Inspiral, the determination of the orbital evolution demands that the motion of the small mass be continuously corrected by the self-force, i.e. the self-consistent evolution. At each of the integration steps, the self-force must be computed over an adequate number of modes; further, a differential-integral system of general relativistic equations is to be solved and the outputs regularised for suppressing divergences. Finally, for the provision of the computational power, parallelisation is under examination.Comment: IX Lisa Conference (held the 21-25 May 2012 in Paris) Proceedings by the Astronomical Society of the Pacific Conference Seri

From EGEE OPerations Portal towards EGI OPerations Portal

International audienceEGEE to EGI structure based on NGIs evolution induces a large move from the operations that will rely on a sustainable and largely decentralized model. One of the key evolutions for the challenge in the regionalisation relies in the scalability and the flexibility required regarding information source types and information handling. For 5 years, we have developed and maintained a standard-based component that allows us to address both theses issues. This open-source tool, named Lavoisier, has been a critical success factor for the operations dashboard, one of the Operations Portal main features. Indeed, it enables coherent efficient and reliable data handling which is customizable and scalable, as Lavoisier is an extensible service designed to provide a unified view of data collected from multiple heterogeneous data sources. Data views are represented and accessed as XML documents through standard languages such as XSLT, XPath. Moreover, scalability and reliability are enforced by a caching mechanism adaptable to specific data sources and use-cases. We will namely expose how the concept and the implementation enable clear roles separation between plug-in developer, service configuration administrator or end-user. Also, maintainability of the portal code has increased dramatically as the latter is now independent from the data sources technology or from the cache management policies. Finally, integration of data has recently been simplified as the service administrator proceeds now through web interface

Clathration of Volatiles in the Solar Nebula and Implications for the Origin of Titan's atmosphere

We describe a scenario of Titan's formation matching the constraints imposed by its current atmospheric composition. Assuming that the abundances of all elements, including oxygen, are solar in the outer nebula, we show that the icy planetesimals were agglomerated in the feeding zone of Saturn from a mixture of clathrates with multiple guest species, so-called stochiometric hydrates such as ammonia hydrate, and pure condensates. We also use a statistical thermodynamic approach to constrain the composition of multiple guest clathrates formed in the solar nebula. We then infer that krypton and xenon, that are expected to condense in the 20-30 K temperature range in the solar nebula, are trapped in clathrates at higher temperatures than 50 K. Once formed, these ices either were accreted by Saturn or remained embedded in its surrounding subnebula until they found their way into the regular satellites growing around Saturn. In order to explain the carbon monoxide and primordial argon deficiencies of Titan's atmosphere, we suggest that the satellite was formed from icy planetesimals initially produced in the solar nebula and that were partially devolatilized at a temperature not exceeding 50 K during their migration within Saturn's subnebula. The observed deficiencies of Titan's atmosphere in krypton and xenon could result from other processes that may have occurred both prior or after the completion of Titan. Thus, krypton and xenon may have been sequestrated in the form of XH3+ complexes in the solar nebula gas phase, causing the formation of noble gas-poor planetesimals ultimately accreted by Titan. Alternatively, krypton and xenon may have also been trapped efficiently in clathrates located on the satellite's surface or in its atmospheric haze.Comment: Accepted for publication in The Astrophysical Journa

EELA Operations: A standalone regional dashboard implementation

International audienceGrid operators in EGEE use a dedicated dashboard as their central operational tool, stable and scalable for the last 5 years despite continuous upgrade from specifications by users, monitoring tools or data providers. In EGEE-III, regionalisation of operations led the tool developers to conceive a standalone instance of this tool. Hereby, we will present the concept and the EELA-II implementation. Indeed, there-engineering of this tool led to an easily deployable package that canconnect to EELA-II specific information sources such as EVENTUM, EELAGOCDB like or SAM EELA instance through the three components of thepackage: the generic and scalable data access mechanism, Lavoisier; thewidely spread php framework Symfony, for configuration flexibility and a Mysql database

Finger creases lend a hand in Kabuki syndrome.

International audienceKabuki syndrome (KS) is a rare syndrome associating malformations with intellectual deficiency and numerous visceral, orthopedic, endocrinological, immune and autoimmune complications. The early establishment of a diagnostic of KS leads to better care of the patients and therefore prevents complications such as perception deafness, severe complications of auto-immune diseases or obesity. However, the diagnosis of KS remains difficult because based on the appreciation of facial features combined with other highly variable features. We describe a novel sign, namely the attenuation and/or congenital absence of the IPD crease of the third and fourth fingers associated with limitation of flexion of the corresponding joints, which seems to be specific of KS and could help the clinician to diagnose KS

Intimating History: (re)-furnishing Versailles for Louis-Philippe's Musée d'Histoire de France (1834-1837)

Abstract The constitution and opening of the Musée Historique de Versailles counts as among the most important undertakings of nineteenth century French cultural policy. It appeared as an explicit manifesto for national reconciliation, in the context of the constitutional monarchy's desire to establish its historical place in the long line of princes and regimes that were considered as the builders of a millenary nation. It appeared also as the best way for the public authority to preserve the castle, since the end of the Revolutionary period had presented each changing regime with the difficulty of dealing with this exceptional monument both in symbolic terms and in relation to its maintenance. 8

Exploring the regional-scale potential of the use of wood products in non-residential buildings : a building permits-based quantitative approach

In the construction sector, wood products are gaining interest. Methods are necessary to quantify material use and evaluate their potential effects. When quantifying the building material consumption, many studies are limited to residential buildings due to the lack of data for non-residential buildings. This research aimed at investigating a methodology to account for non-residential building material consumption. A method to estimate the volume of wood products in the structures of the new non-residential buildings was presented. Then, projections of the estimation were suggested according to three scenarios (minimum, average, and maximum). Sensitivity analyses highlighted the parameters that present the greatest contribution to the scenarios. The relative importance of the estimation to the total harvesting of all wood markets was also assessed. Despite the high uncertainty in wood consumption for non-residential building structures, the estimation had a small weight on the total harvesting of the Quebec province. The results showed how and when the resource availability could be constrained depending on the assumptions. This method can serve for life cycle inventory for an environmental assessment or wood flow analysis, but more research on the material composition of the non-residential building archetypes is necessary