79 research outputs found
DĂ©veloppement dâune ACV consĂ©quentielle dynamique : augmentation de la pĂ©nĂ©tration 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 matĂ©riaux de construction, et leur teneur en carbone peut faire des bĂątiments un puits de carbone temporaire. Les avancĂ©es technologiques, la formation, et la synergie qui se mettent en place entre les acteurs industriels et institutionnels participent aussi Ă lâacceptation du bois dans les bĂątiments. Avec le nombre croissant de publications montrant que l'utilisation du bois dans la construction peut ĂȘtre une option Ă©cologique, les dĂ©cideurs pourraient s'orienter vers une utilisation Ă grande Ă©chelle. Cependant, l'utilisation Ă grande Ă©chelle des produits du bois dans les bĂątiments nĂ©cessite une meilleure comprĂ©hension de ses consĂ©quences pour soutenir les politiques de lutte contre le changement climatique (CC). Câest pourquoi un cadre d'Ă©valuation de lâutilisation croissante du bois dans la construction est dĂ©veloppĂ© dans cette thĂšse. Il se fonde sur une modĂ©lisation prospective dâanalyse des flux de matiĂšre (AFM) pour supporter la mĂ©thode dâanalyse du cycle de vie (ACV). Le secteur de la construction non rĂ©sidentielle (NR) en bois au QuĂ©bec est un bon exemple car les gouvernements (provincial et fĂ©dĂ©ral) cherchent Ă lâaccroitre. En 2008, lâindustrie forestiĂšre subit une crise suite Ă la baisse de ses exportations. Puis, Ă la suite de stratĂ©gies successives, le gouvernement quĂ©bĂ©cois propose la premiĂšre version de la charte du bois en 2013. Elle reprĂ©sente son engagement Ă augmenter lâutilisation du bois dans la construction pour soutenir lâindustrie forestiĂšre et de la construction, ainsi que pour rĂ©duire les Ă©missions de gaz Ă effet de serre (GES). Les bĂątiments rĂ©sidentiels unifamiliaux Ă©tant majoritairement faits en bois, lâengagement vise la construction non rĂ©sidentielle et multifamiliale.
Les ACV sur le bois ont des lacunes qui limitent la reprĂ©sentation et lâanalyser des consĂ©quences de son utilisation croissante Ă lâĂ©chelle dâune rĂ©gion pour un stock de bĂątiment. PremiĂšrement, la littĂ©rature suggĂšre que la substitution de matĂ©riaux de construction conventionnels par des produits en bois est souhaitable pour attĂ©nuer les Ă©missions de GES. Elle prĂ©sente la diffĂ©rence de lâimpact au CC qui est attribuable Ă la comparaison de deux bĂątiments, structures, ou produits. Les autres impacts environnementaux sont moins abordĂ©s. Le rĂ©sultat dâune Ă©valuation Ă lâĂ©chelle d'une structure spĂ©cifique ou dâun bĂątiment est difficilement applicable Ă dâautres cas dâĂ©tudes ou extrapolable Ă lâĂ©chelle dâune rĂ©gion pour un stock de bĂątiments hĂ©tĂ©rogĂšnes. De plus, ces Ă©valuations ne permettent pas de considĂ©rer lâimpact des processus impliquĂ©s ou Ă©vitĂ©s en consĂ©quence de cette substitution. Lâidentification de ces processus est un dĂ©fi en ACV consĂ©quentielle (ACV-C). Enfin, une utilisation du bois Ă grande Ă©chelle implique de comprendre le niveau de rĂ©colte par rapport disponibilitĂ© de la ressource, mais la quantification des flux de matiĂšre dans le secteur du bĂątiment est limitĂ©e aux bĂątiments rĂ©sidentiels en raison dâun manque de donnĂ©es pour les bĂątiments NR.
Dans le but dâamĂ©liorer lâĂ©valuation des impacts environnementaux causĂ©s par une augmentation de lâutilisation du bois dans la construction, la rĂ©ponse aux lacunes est organisĂ©e de la façon suivante. PremiĂšrement, des paramĂštres ont dĂ» ĂȘtre Ă©laborĂ© pour estimer et projeter lâutilisation du bois dans les structures NR. Cette estimation sert de flux de rĂ©fĂ©rence. Elle est intĂ©grĂ©e dans une AFM pour comprendre lâimportance de ses valeurs extrĂȘmes par rapport Ă la rĂ©colte totale du bois et la limite de la ressource disponible. Des facteurs de substitution de matiĂšres ont Ă©tĂ© crĂ©Ă©s Ă partir de diffĂ©rentes structures de la littĂ©rature. Ils sont appliquĂ©s Ă la quantitĂ© estimĂ©e des produits en bois qui sont utilisĂ©s. Enfin, la modĂ©lisation dynamique de la croissance des arbres et du roulement de stock permet de crĂ©er une cohĂ©rence temporelle entre lâinventaire des flux Ă©lĂ©mentaires et la caractĂ©risation dynamique de lâimpact.
Ce projet de recherche apporte plusieurs contributions. Il permet dâestimer lâutilisation croissante du bois dans la construction NR Ă lâĂ©chelle dâune rĂ©gion. Ce type dâestimation est utile pour lâinventaire des flux de rĂ©fĂ©rence dâune ACV et pour complĂ©ter une AFM. IntĂ©grĂ©e dans une AFM, elle permet de supporter lâidentification de ressources contraintes dans le cas dâune ACV-C. Ce projet propose Ă©galement des facteurs de substitution fonctionnelle pour le bois de structure par rapport Ă une combinaison de lâacier et du bĂ©ton. Ils sont applicables pour les ACV-C et leur variabilitĂ© permet de considĂ©rer diffĂ©rentes structures et un intervalle dâimpact dĂ©placĂ© pour tous les indicateurs environnementaux afin de faciliter l'interprĂ©tation dâune extrapolation Ă grande Ă©chelle. Enfin, le projet met en Ă©vidence lâimportance relative entre la substitution, les stratĂ©gies de fin de vie, et la sĂ©questration temporaire du carbone. Pour une cohorte de bĂątiments, le stockage du carbone dans celle-ci est temporel pendant sa durĂ©e de vie. Cependant, Ă la dimension de cohortes successives, le stockage du carbone est plus durable dans le temps, soit pendant la durĂ©e de vie du stock. Le cumul du forçage radiatif nâĂ©tait pas Ă©tudiĂ© Ă cette Ă©chelle dans le cas dâune rĂ©gĂ©nĂ©ration forestiĂšre aprĂšs la rĂ©colte.
Au Canada, la gestion de la forĂȘt se base sur la possibilitĂ© annuelle de coupe qui est dĂ©terminĂ©e par les gouvernements provinciaux pour s'assurer que les taux de rĂ©colte demeurent Ă des niveaux durables. Cette possibilitĂ© forestiĂšre traduit le mĂštre cube de bois disponible pour la rĂ©colte. L'AFM a permis de montrer lâimportance de lâestimation maximale du volume rĂ©coltĂ© pour les nouvelles structures par rapport Ă la possibilitĂ© forestiĂšre et Ă lâĂ©volution de la rĂ©colte pour les exportations et de la rĂ©colte totale. Plus de recherche empirique est nĂ©cessaire sur lâanalyse des flux du bois des autres marchĂ©s. La modĂ©lisation de la substitution a permis d'Ă©valuer non seulement le dĂ©placement d'impact sur le CC, mais aussi sur la santĂ© humaine, la qualitĂ© des Ă©cosystĂšmes et les ressources. Les stratĂ©gies et politiques qui rĂ©pondent Ă l'urgence climatique devraient Ă©galement prĂȘter attention Ă la qualitĂ© des Ă©cosystĂšmes. Dans le scĂ©nario de substitution minimale, le bois Ă©vite peu dâacier et de bĂ©ton. De plus, la production unitaire des grades dâacier et de bĂ©ton utilisĂ©s provoque moins dâimpacts que celle des grades utilisĂ©s dans les scĂ©narios de substitution moyenne et maximale. Dans ce scĂ©nario minimum, câest la sĂ©questration du carbone qui permet un Ă©vitement de lâimpact sur le CC. A lâĂ©chelle de la structure, le maintien de cet Ă©vitement au cours du temps dĂ©pendant de la fin de vie de celle-ci. A lâĂ©chelle du stock de structure, le maintien de lâĂ©vitement dĂ©pend de son renouvellement et de la fin de vie des structures. Enfin, utiliser un facteur de caractĂ©risation statique pour le CC pour un inventaire dynamique consĂ©quentielle peut conduire Ă des conclusions opposĂ©es Ă celles dâun facteur dynamique.
Finalement, diffĂ©rentes pistes dâamĂ©lioration sont prĂ©sentĂ©es. En effet, des limites subsistent au niveau de la modĂ©lisation ACV et AFM en matiĂšre de complĂ©tude et de qualitĂ© des donnĂ©es ainsi quâau niveau de la complexitĂ© des mĂ©thodes dâinventaires et dâimpacts dynamiques. Par exemple, la mĂ©thode prĂ©sentĂ©e pour estimer la quantitĂ© de bois pourrait ĂȘtre comparĂ©e Ă dâautres mĂ©thodes, si des donnĂ©es sont disponibles. Une plus grande dĂ©sagrĂ©gation entre les diffĂ©rents produits du bois et leurs secteurs est nĂ©cessaire pour mieux cibler les consĂ©quences potentielles de leurs complĂ©mentaritĂ©s, concurrences et dynamiques de marchĂ©. Une modĂ©lisation plus complĂšte des cycles de carbone forestier permettrait de comprendre si la rĂ©colte peut Ă©viter les Ă©missions de carbone dues aux feux et autres causes de mortalitĂ© des arbres. Enfin, lâimpact sur la qualitĂ© des Ă©cosystĂšmes devrait ĂȘtre plus abordĂ© 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
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