Développement d'une approche expérimentale permettant l'évaluation de la cinématique tridimensionnelle de l'articulation glénohumérale

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

Développement d'une méthode d'analyse du cycle de vie dynamique pour l'évaluation des impacts sur le réchauffement climatique

Le réchauffement climatique de nature anthropique est principalement causé par les émissions de gaz à effet de serre (GES) provenant des différentes activités humaines. Pour réduire l’impact de ces activités sur le climat, il faut être en mesure de quantifier les émissions de GES, ainsi que leur impact relatif sur le réchauffement climatique, afin d’identifier les sources principales et les solutions permettant d’atteindre les objectifs de réduction fixés. Pour ce faire, l’unité de mesure généralement utilisée est le GWP (« Global Warming Potential »), proposé par le Groupe d’experts intergouvernemental sur l’évolution du climat (GIEC), qui transforme les émissions des différents GES en kg CO2-eq. L’utilisation de plus en plus répandue du GWP et des méthodes de comptabilisation des émissions de GES a fait poindre certaines limites concernant les aspects temporels des émissions. En effet, le développement d’un nombre croissant de projets d’atténuation du réchauffement climatique par la foresterie a soulevé la question de l’impact de la séquestration et du stockage temporaire de carbone en forêt. De plus, de récentes méthodes de calcul pour l’empreinte carbone des produits visent à donner une valeur au stockage temporaire de carbone dans des objets issus de la biomasse pendant leur durée de vie. Finalement, certaines études ont démontré l’importance de la considération de la distribution temporelle des émissions de GES lors de l’évaluation de projets s’étendant sur de longues périodes de temps. Pour chacune de ces problématiques individuelles, des approches ont été proposées au cours des dernières années. Par contre, ces approches sont spécifiques à une situation ou à un problème donné. De plus, elles comportent généralement des lacunes. Par exemple, elles s’appliquent seulement aux émissions de CO2 et négligent les autres GES, elles donnent des résultats pour un horizon de temps fixe, etc. L’objectif principal de cette thèse est de développer une méthode d’analyse du cycle de vie (ACV) dynamique pour la catégorie d’impact du réchauffement climatique et de démontrer que cette méthode permet de pallier les lacunes des méthodes existantes concernant les aspects temporels des émissions de GES. La méthode développée doit donc permettre d’analyser l’impact de n’importe quel système de produits dans un cadre temporel cohérent, tout en considérant de façon rigoureuse le devenir atmosphérique de chacun des différents gaz à effet de serre. La première étape à réaliser pour l’obtention d’une ACV dynamique est de développer un inventaire du cycle de vie qui tient compte de la distribution temporelle des émissions. Pour ce faire, le cycle de vie est divisé en pas de temps d’une longueur d’une année et toutes les émissions d’un GES donné ayant lieu à une certaine année sont additionnées pour donner une matrice d’inventaire où chaque ligne représente un type de GES et chaque colonne, une année d’émission. Des facteurs de caractérisation dynamiques sont ensuite développés pour deux indicateurs du réchauffement climatique, soit 1) le forçage radiatif, tel qu’utilisé pour le calcul des GWP et 2) l’augmentation de la température atmosphérique. La méthode développée dans cette thèse permet donc de calculer l’impact de n’importe quel inventaire de GES sur le forçage radiatif et sur la température atmosphérique à tout moment t, en utilisant des facteurs de caractérisation qui sont fonction du temps écoulé entre chaque émission et le moment t. Comme elle utilise des facteurs de caractérisation qui sont fonction du moment de l’émission, l’ACV dynamique permet le calcul des impacts d’émissions de GES réparties dans le temps dans un cadre temporel cohérent. L’application de la méthode à une étude portant sur le remplacement des combustibles fossiles par des biocarburants tout en tenant compte des émissions dues au changement d’affectation des terres démontre que cette incohérence temporelle peut avoir un impact très significatif sur les résultats et sur les décisions qui en découlent. Par exemple, certains biocarburants pourraient être favorisés par une politique exigeant qu’ils atteignent un certain niveau de réduction de GES au bout d’une certaine période de temps si les résultats de l’approche traditionnelle sont utilisés, alors qu’ils seraient exclus suivant les résultats de l’ACV dynamique. Ces résultats démontrent aussi que l’ACV dynamique peut être appliquée à n’importe quel type de profil temporel ou de système de produits, contrairement à certaines approches existantes développées pour le cas particulier des biocarburants. Les résultats obtenus pour l’évaluation d’un projet de compensation d’une émission de GES par la foresterie démontrent que la séquestration d’une certaine quantité de carbone en forêt ne peut compenser entièrement, à court ou à moyen terme, l’impact causé par une émission initiale équivalente à cause du délai de séquestration et que l’ACV dynamique, en calculant l’impact en fonction du temps, permet d’analyser la sensibilité des résultats au choix d’un horizon temporel. Ces résultats démontrent aussi que l’utilisation unique du forçage radiatif cumulatif pour évaluer l’impact sur le réchauffement climatique n’est pas suffisante, puisque cet indicateur ne permet pas de tenir compte des impacts liés à l’augmentation absolue de température. L’utilisation des deux indicateurs, desquels peuvent découler des conclusions différentes, permet donc de prendre des décisions mieux informées, en se basant sur un éventail d’impacts plus grand. Finalement, la comparaison entre l’ACV dynamique et les méthodes existantes pour le calcul de l’empreinte carbone démontrent que la méthode développée dans cette thèse propose un calcul plus rigoureux et permet une analyse plus flexible des résultats. En effet, contrairement aux autres approches, l’ACV dynamique tient compte de la dynamique de séquestration du carbone dans la biomasse, considère le devenir atmosphérique spécifique à chaque GES par l’utilisation de facteurs de caractérisation dynamiques propres à chacun des gaz et ne nécessite pas la détermination d’un horizon temporel arbitraire avant le calcul. Le développement d’une méthodologie générale pour l’intégration des aspects temporels en analyse du cycle de vie est une première dans le domaine et apporte un certain nombre de défis. Différentes opportunités de recherche sont proposées afin d’améliorer la rigueur et la justesse des analyses effectuées à l’aide de cette méthode et d’étendre son application. • Le développement de facteurs de caractérisation dynamiques pour le réchauffement climatique variant avec la concentration atmosphérique en CO2; • La considération des impacts causés par les modifications de l’albedo lors d’un changement d’affectation des terres; • La modélisation des impacts sur le réchauffement climatique au niveau dommage; • Le développement de facteurs de caractérisation dynamiques pour d’autres catégories d’impacts; • Le développement d’une méthode pour l’opérationnalisation du calcul d’inventaire temporel; • L’adaptation des banques de données ACV à la temporalisation de l’inventaire; • Le développement des aspects prospectifs en ACV. ---------- Anthropogenic global warming is mainly caused by the greenhouse gas (GHG) emissions coming from human activities. In order to reduce their impact on the climate, GHG emissions must be quantified, as well as their relative impact on global warming, so that the main sources are identified and the right solutions are implemented to reach the reduction targets. The metric used to compare the different GHGs is the Global Warming Potential (GWP), proposed by the International Panel on Climate Change (IPCC), which converts GHG emissions into kg CO2-eq. The widespread use of GWP and GHG accounting methods has uncovered some limits regarding the temporal aspects of GHG emissions. The increasing number of climate mitigation projects has raised issues about the assessment of temporary carbon sequestration and storage in forests. Moreover, some recently published methods for carbon footprint calculation aim to give a value to temporary carbon storage in long-lived products made from biomass. Finally, some studies have shown the importance of considering the timing of GHG emissions while assessing the impacts of projects over long time frames. For each of these issues, some approaches are proposed in the scientific literature. However, each of these approaches has been developed for a specific situation, and some flaws have been identified. For instance, they can only be applied to CO2 emissions, they provide results for a fixed time horizon, etc. The main objective of this thesis is to develop a dynamic life cycle assessment (LCA) method for global warming and to show that this method alleviates the deficiencies identified in the existing approaches regarding the temporal aspects of GHG emissions. The dynamic LCA method must enable the assessment of any type of product system over a consistent time frame, while rigorously considering the specific atmospheric fate of each greenhouse gas. The first step in performing a dynamic LCA is to develop a life cycle inventory which considers the temporal profile of emissions. The life cycle is thus divided in one-year time steps, and all the emissions of a given GHG occurring on a given year are summed to get an inventory matrix for which each row stands for a particular GHG and each column, for the year of emission. Dynamic characterization factors are then developed for two different global warming indicators: 1) radiative forcing, as used in GWP, and 2) increase in atmospheric temperature. The method developed in this thesis aims to calculate the impact of any GHG inventory on radiative forcing and atmospheric temperature at any time t, using characterizations factors that depend on the time elapsed between each emission and time t. By using dynamic characterization factors that depend on the moment of emission, dynamic LCA calculates the global warming impact of GHG emissions over a consistent time frame. The use of dynamic LCA to assess the impact of the replacement of fossil fuels with biofuels while considering land-use change emissions shows that the temporal inconsistency has a very significant impact on LCA results, and on the decisions taken. For instance, some biofuels could be favored by regulations asking for a given GHG reduction over a specified time frame if using the traditional approach, while they would be rejected if using dynamic LCA. These results also show that dynamic LCA can be applied to any type of temporal profile or product system, in opposition to some existing approaches that have been developed for the particular case of biofuel assessment. The results provided by the assessment of a climate mitigation project through forestry with dynamic LCA show that the sequestration of a given amount of carbon in trees cannot fully compensate an equivalent emission, on a short- or a mid-term perspective, because of the sequestration delay, and that since it provides the time-dependent impact on global warming, the dynamic LCA approach allows analyzing the sensitivity of the results to the choice of a time horizon. These results also show that cumulative radiative forcing is not sufficient as a single global warming indicator, since it does not consider the impacts related to the absolute increase in temperature. Different conclusions can be drawn from the two different indicators, and the use of both of them would make decision making based on a wider range of climate change impacts. Finally, the comparison between dynamic LCA and the existing methods for carbon footprint calculation show that the method developed in this thesis provides more rigorous results and allows for a more flexible analysis. Unlike the other approaches, dynamic LCA takes into account the temporal profile of the sequestration of carbon in trees, it considers the specific atmospheric fate of every GHG with different characterization factors, and it does not require the determination of an arbitrary time horizon prior to the calculation. The integration of temporal aspects in life cycle assessment brings new challenges. Some future research opportunities are proposed in order to improve the validity and accuracy of the method, as well as to expand its use. • Development of dynamic characterization factors for global warming that takes into account the variations of the atmospheric CO2 concentration; • Consideration of the albedo effects caused by land-use change; • Damage modeling of the global warming impacts in life cycle assessment; • Development of dynamic characterization factors for other impact categories; • Development of a method for the calculation of temporal life cycle inventories; • Adaptation of the life cycle databases to the integration of temporal aspects in LCA; • Development of prospective LCA

Regionalized terrestrial ecotoxicity assessment of copper-based fungicides applied in viticulture

Life cycle assessment has been recognized as an important decision-making tool to improve the environmental performance of agricultural systems. Still, there are certain modelling issues related to the assessment of their impacts. The first is linked to the assessment of the metal terrestrial ecotoxicity impact, for which metal speciation in soil is disregarded. In fact, emissions of metals in agricultural systems contribute significantly to the ecotoxic impact, as do copper-based fungicides applied in viticulture to combat downy mildew. Another issue is linked to the ways in which the intrinsic geographical variability of agriculture resulting from the variation of management practices, soil properties, and climate is addressed. The aim of this study is to assess the spatial variability of the terrestrial ecotoxicity impact of copper-based fungicides applied in European vineyards, accounting for both geographical variability in terms of agricultural practice and copper speciation in soil. This first entails the development of regionalized characterization factors (CFs) for the copper used in viticulture and then the application of these CFs to a regionalized life-cycle inventory that considers different management practices, soil properties, and climates in different regions, namely Languedoc-Roussillon (France), Minho (Portugal), Tuscany (Italy), and Galicia (Spain). There are two modelling alternatives to determine metal speciation in terrestrial ecotoxicity: (a) empirical regression models; and (b) WHAM 6.0, the geochemical speciation model applied according to the soil properties of the Harmonized World Soil Database (HWSD). Both approaches were used to compute and compare regionalized CFs with each other and with current IMPACT 2002+ CF. The CFs were then aggregated at different spatial resolutions—global, Europe, country, and wine-growing region—to assess the uncertainty related to spatial variability at the different scales and applied in the regionalized case study. The global CF computed for copper terrestrial ecotoxicity is around 3.5 orders of magnitude lower than the one from IMPACT 2002+, demonstrating the impact of including metal speciation. For both methods, an increase in the spatial resolution of the CFs translated into a decrease in the spatial variability of the CFs. With the exception of the aggregated CF for Portugal (Minho) at the country level, all the aggregated CFs derived from empirical regression models are greater than the ones derived from the method based on WHAM 6.0 within a range of 0.2 to 1.2 orders of magnitude. Furthermore, CFs calculated with empirical regression models exhibited a greater spatial variability with respect to the CFs derived from WHAM 6.0. The ranking of the impact scores of the analyzed scenarios was mainly determined by the amount of copper applied in each wine-growing region. However, finer spatial resolutions led to an impact score with lower uncertainty

How Can Temporal Considerations Open New Opportunities for LCA Industry Applications?

International audienceOpportunities of considering time in LCA studies are shown through our "dynamic" system and impact modeling of different domestic hot water systems. Our "dynamic" carbon footprint modeling changed the conclusion of the equivalent "non-dynamic" evaluation which shows that temporal consideration might provide a more representative assessment. The temporally characterized distributions of elementary flows we used also bring new analysis opportunities for practitioners. As an example, we believe that such information will enable the simple identification of products with high potential for future environmental improvement. Describing the temporal distributions of natural resource extraction could be another opportunity for dynamic modeling as they would provide valuable information on when and how consumption could be an issue

Assessing Temporary Carbon Sequestration and Storage Projects through Land Use, Land-Use Change and Forestry: Comparison of Dynamic Life Cycle Assessment with Ton-Year Approaches

In order to properly assess the climate impact of temporary carbon sequestration and storage projects through land-use, land-use change and forestry (LULUCF), it is important to consider their temporal aspect. Dynamic life cycle assessment (dynamic LCA) was developed to account for time while assessing the potential impact of life cycle greenhouse gases (GHG) emissions. In this paper, the dynamic LCA approach is applied to a temporary carbon sequestration project through afforestation, and the results are compared with those of the two principal ton-year approaches: the Moura-Costa and the Lashof methods. The dynamic LCA covers different scenarios, which are distinguished by the assumptions regarding what happens at the end of the sequestration period. In order to ascertain the degree of compensation of an emission through a LULUCF project, the ratio of the cumulative impact of the project to the cumulative impact of a baseline GHG emission is calculated over time. This ratio tends to 100% when assuming that, after the end of the sequestration project period, the forest is maintained indefinitely. Conversely, the ratio tends to much lower values in scenarios where part of the carbon is released back to the atmosphere. The comparison of the dynamic LCA approach with the Moura-Costa and the Lashof methods shows that dynamic LCA is a more flexible approach as it allows the consideration of every life cycle stage of the project and it gives decision makers the opportunity to test the sensitivity of the results to the choice of different time horizons.JRC.H.8-Sustainability Assessmen

Temporally-differentiated biogenic carbon accounting of wood building product life cycles

ABSTRACT: Although standards have identified temporary carbon storage as an important element to consider in wood product LCAs, there has been no consensus on a methodology for its accounting. This work aims to improve the accounting of carbon storage and fluxes in long-life wood products in LCA. Biogenic carbon from harvested roundwood logs were tracked using the Carbon Budget Model Framework for Harvested Wood Products (CBMF-HWP). Carbon flows through wood product manufacturing, building life and end-of-life phases, and carbon stocks and fluxes from harvest to the atmosphere were estimated. To cover the products commonly used in the Canadian building industry, a range of softwood products types, provinces and territories and building lifetimes were considered. In addition, policy scenarios were considered in order to model the effects of dynamic parameters through time as a policy target is reached. Most wood products have similar emissions profiles, though cross-laminated timber has higher sawmill emissions and oriented-strand board has higher initial post-demolition emissions. The region of construction is also predictive of the initial post-demolition emissions. Higher recycling rates shift materials from landfills into subsequent product systems, thus avoiding landfill emissions. Landfill decay rates are affected by climate and results in a large range of landfill emissions. The degree of postponement of end-of-life emissions is highly dependent upon the wood product type, region and building lifespan parameters. This work develops biogenic carbon profiles that allows for modelling dynamic cradle-to-grave LCAs of Canadian wood products

Assessment of Regional Bone Density in Fractured Vertebrae Using Quantitative Computed Tomography

Study DesignCohort study.PurposeThe aim of this study is to propose and evaluate a new technique to assess bone mineral density of fractured vertebrae using quantitative computed tomography (QCT).Overview of LiteratureThere is no available technique to estimate bone mineral density (BMD) at the fractured vertebra because of the alterations in bony structures at the fracture site.MethodsForty patients with isolated fracture from T10 to L2 were analyzed from the vertebrae above and below the fracture level. Apparent density (AD) was measured based on the relationship between QCT images attenuation coefficients and the density of calibration objects. AD of 8 independent regions of interest (ROI) within the vertebral body and 2 ROI within the pedicles of vertebrae above and below the fractured vertebra were measured. At the level of the fractured vertebra, AD was measured at the pedicles, which are typically intact. AD of the fractured vertebral body was linearly interpolated, based on the assumption that AD at the fractured vertebra is equivalent to the average AD measured in vertebrae adjacent to the fracture. Estimated and measured AD of the pedicles at the fractured level were compared to verify our assumption of linear interpolation from adjacent vertebrae.ResultsThe difference between the measured and the interpolated density of the pedicles at the fractured vertebra was 0.006 and 0.003 g/cm3 for right and left pedicle respectively. The highest mean AD located at the pedicles and the lowest mean AD was found at the anterior ROI of the vertebral body. Significant negative correlation exist between age and AD of ROI in the vertebral body.ConclusionsThis study suggests that the proposed technique is adequate to estimate the AD of a fractured vertebra from the density of adjacent vertebrae

Globalization, Financial Depth, and Inequality in Sub-Saharan Africa

ISSN:0948-3349ISSN:1614-750

Overview of the assessment practices of occupational therapists working in Quebec

Description. L'évaluation du client est primordiale dans la pratique de l'ergothérapie, notamment pour établir les priorités de traitement et pour vérifier l'efficacité des interventions. Les pratiques évaluatives des ergothérapeutes sont cependant peu documentées. But. Dresser un portrait des pratiques évaluatives des ergothérapeutes du Québec selon les dimensions personne-environnement-occupation et les clientèles. Méthodologie. Une enquête transversale a été réalisée à l'aide d'un sondage en ligne envoyé aux ergothérapeutes du Québec. Résultats. En pédiatrie, les ergothérapeutes utilisent majoritairement des outils standardisés des aptitudes physiques et neurologiques. L'évaluation d'adultes cible principalement les aptitudes physiques et la productivité. Auprès des aînés, l'évaluation repose surtout sur les aspects fonctionnels, particulièrement les aptitudes physiques, les soins personnels et la sécurité à domicile, et sur le dépistage des difficultés cognitives. Implications pour la pratique. L'évaluation ergothérapique serait généralement axée sur les aptitudes physiques. Pour assurer une approche holistique, l'occupation et l'environnement devraient être davantage considérés dans l'évaluation.Abstract : Background. In occupational therapy practice, client assessments are essential for establishing treatment priorities and determining the effectiveness of interventions. However, occupational therapists' assessment practices are not well documented. Purpose. This work aimed to provide an overview of the assessment practices of Quebec occupational therapists based on the person–environment–occupation components and clienteles. Method. A cross-sectional survey was conducted using an online survey that was sent to occupational therapists in Quebec. Findings. In paediatrics, occupational therapists tend to use standardized tools to assess physical and neurological abilities. Adult assessment focuses mainly on physical abilities and productivity. For seniors, assessment focuses mainly on functional aspects (physical abilities, personal care, and home safety) and screening for cognitive difficulties. Implications. Occupational therapy assessment mostly focuses on physicial abilities. To ensure a holistic approach, more occupational and environmental components should be included in the assessment practices

Global guidance on environmental life cycle impact assessment indicators: impacts of climate change, fine particulate matter formation, water consumption and land use

Purpose Guidance is needed on best-suited indicators to quantify and monitor the man-made impacts on human health, biodiversity and resources. Therefore, the UNEP-SETAC Life Cycle Initiative initiated a global consensus process to agree on an updated overall life cycle impact assessment (LCIA) framework and to recommend a non-comprehensive list of environmental indicators and LCIA characterization factors for (1) climate change, (2) fine particulate matter impacts on human health, (3) water consumption impacts (both scarcity and human health) and 4) land use impacts on biodiversity. Methods The consensus building process involved more than 100 world-leading scientists in task forces via multiple workshops. Results were consolidated during a 1-week Pellston Workshop™ in January 2016 leading to the following recommendations. Results and discussion LCIA framework: The updated LCIA framework now distinguishes between intrinsic, instrumental and cultural values, with disability-adjusted life years (DALY) to characterize damages on human health and with measures of vulnerability included to assess biodiversity loss. Climate change impacts: Two complementary climate change impact categories are recommended: (a) The global warming potential 100 years (GWP 100) represents shorter term impacts associated with rate of change and adaptation capacity, and (b) the global temperature change potential 100 years (GTP 100) characterizes the century-scale long term impacts, both including climate-carbon cycle feedbacks for all climate forcers. Fine particulate matter (PM2.5) health impacts: Recommended characterization factors (CFs) for primary and secondary (interim) PM2.5 are established, distinguishing between indoor, urban and rural archetypes. Water consumption impacts: CFs are recommended, preferably on monthly and watershed levels, for two categories: (a) The water scarcity indicator “AWARE” characterizes the potential to deprive human and ecosystems users and quantifies the relative Available WAter REmaining per area once the demand of humans and aquatic ecosystems has been met, and (b) the impact of water consumption on human health assesses the DALYs from malnutrition caused by lack of water for irrigated food production. Land use impacts: CFs representing global potential species loss from land use are proposed as interim recommendation suitable to assess biodiversity loss due to land use and land use change in LCA hotspot analyses. Conclusions The recommended environmental indicators may be used to support the UN Sustainable Development Goals in order to quantify and monitor progress towards sustainable production and consumption. These indicators will be periodically updated, establishing a process for their stewardship