Conception d'un système structural permettant l'utilisation de l'ossature légère modulaire dans les bâtiments de grande hauteur

Pour répondre à la fois à la croissance de la population urbaine mondiale et aux changements climatiques, de nouveaux systèmes structurels à haut niveau de préfabrication et utilisant des matériaux renouvelables doivent être développés. L'ossature légère peut avoir un taux de préfabrication très élevé, mais est actuellement limitée à 6 étages. Un nouveau système structurel qui pourrait permettre l'utilisation de la construction modulaire à ossature légère dans les immeubles de grande hauteur est modélisé et analysé. Ce système est composé d'une hyperstructure supportant les charges de sous-structures superposées de 4 étages en ossature légère. Des hyperstructures de 20 étages, en glulam, en béton et hybride bois-béton sont conçues selon le Code national du bâtiment du Canada 2015 et comparées. Un modèle simplifié pour les modules à ossature légère selon la norme CSA O86-19 est proposé. L'interaction entre les deux systèmes et l'impact sur les sous-structures sont analysés. Les résultats de l'analyse du spectre de réponse sismique et de l'analyse dynamique du vent montrent qu'avec une hyperstructure en glulam, les modules peuvent être reliés aux colonnes et aux planchers ou seulement aux planchers. Avec une hyperstructure en béton, les modules doivent être connectés aux colonnes et aux noyaux. Pour les murs de refend, des compositions standards suffisent à résister au cisaillement induit par les charges gravitationnelles, de vent et sismiques. L'analyse indique que le système pourrait être viable, mais des recherches plus approfondies devraient être menées, en particulier sur les connexions et la résistance incendie.To respond to both global urban population growth and climate change, new structural systems with a high level of prefabrication and renewable materials need to be developed. Light-frame construction can have a very high prefabrication rate but is currently limited to 6 storeys. A new structural system that could allow the use of light-frame modular construction in high-rise buildings is modeled and analysed. This system consists of a hyperstructure supporting the loads of 4-storey light-frame superimposed substructures. Twenty-storey hyperstructures, in glulam, concrete and wood-concrete hybrid are designed according to the 2015 National Building Code of Canada and compared. A simplified model for the light-frame modules according to the CSAO86-19 is proposed. The interaction between the two systems and the impact on the substructures are analysed. The results of the seismic response spectrum analysis and the dynamic wind analysis show that with a glulam hyperstructure, the modules can be connected to the columns and floors or only to the floors. With a concrete hyperstructure, the modules must be connected to the columns and the cores. Standard shearwall assemblies are sufficient to resist the shear induced by gravity, wind and seismic loads. The analysis indicates that the system could be viable, but further research should be carried out, particularly on connections and fire resistance

Finite element study of hyperstructure systems with modular light‐frame construction in high‐rise buildings

To answer both the growth of the world's urban population and the climate changes, new structural systems with high prefabrication levels and renewable materials need to be developed. A novel structural system that could enable the use of modular light‐frame construction in high‐rise buildings was modeled and analyzed. This system was achieved by having a hyperstructure carrying the loads of four‐story light‐frame superposed substructures. Two 20‐story hyperstructures, one using glulam and another one using reinforced concrete, were designed according to the 2015 National Building Code of Canada and compared. A simplified model for the light‐frame modules according to the CSA O86‐19 was proposed. The interaction between both systems and the impact on the substructures were analyzed. The results of the response spectrum analysis and dynamic wind analysis show that, with a glulam hyperstructure, modules could be connected to the columns and the floors or only to the floors. With a concrete hyperstructure, the modules must be connected to the columns and the cores. For both systems, the design of shearwalls on the short side of the modules is governed by the lateral deformation imposed by seismic forces, while the design of shearwalls on the long side of the modules is governed by the vertical deformation of the primary beams under gravity loads. Standard shearwall assemblies are sufficient to resist the shear induced by gravitational, wind and seismic loads. The analysis indicates that the system could be viable, but more research should be especially performed on the connections between the substructures and the hyperstructure

Variability of CD3 membrane expression and T cell activation capacity

αβT cells have a wide distribution of their CD3 membrane density. The aim of this paper was to evaluate the significance of the CD3 differential expression on T cell subsets. Analysis was performed on healthy donors and renal transplant patients by flowcytometry The results obtained are : 1-CD3 expression was widely distributed (CV =38.3±3.1 to (43±2.3%). 2-The CD4, CD8,CD45 and forward scatter were similarly distributed. 3-The diversity of CD3 expression was direcly related to the clonotypes: γ9, non γ9 from γδT cells and Vβ clonotype from αβT cells (e.g.: Vβ3FITC 7980±1628 Vβ8PE: Vβ20-FITC 11768±1510). 4-Using a computer simulation, we could confirm differential kinetics of T cell activation according to the initial parameters. Finally, in vitro activation was significantly higher on Vβ8 and Vβ9 (high CD3) compared to Vβ2 and Vβ3 (low CD3, P=0.040 to 0.0003). In conclusion: T cells have highly heterogeneous CD3 expression, possibly predetermined and with clear functional significance

Implementasi Program Pemberdayaan Ekonomi Rakyat Melalui Program Mamangun Tuntang Mahaga Lewu (Pm2l) (Studi Kasus Di Dua Desa Tertinggal Di Kalimantan Tengah)

This study aims to determine the implementation of the program of economic empowerment of the people through the program mamangun Tuntang mahaga Lewu (PM2L). Writing method used is qualitative. This method was chosen because it examines the phenomenon of something in more depth, and more able to understand the phenomenon that until now has not been known. Through this study were obtained in the implementation of key information that PM2L are several stages to go through the stage of coordination, socialization, implementation of the action, coaching, monitoring and evaluation. In general, the stages through which it has not been optimal program implementation in practice, especially in terms of stages of development

Willow short-rotation production systems in Canada and Northern United States: A review

Willow short rotation coppice (SRC) systems are becoming an attractive practice because they are a sustainable system fulfilling multiple ecological objectives with significant environmental benefits. A sustainable supply of bioenergy feedstock can be produced by willow on marginal land using well-adapted or tolerant cultivars. Across Canada and northern U.S.A., there are millions of hectares of available degraded land that have the potential for willow SRC biomass production, with a C sequestration potential capable of offsetting appreciable amount of anthropogenic green-house gas emissions. A fundamental question concerning 1 sustainable SRC willow yields was whether long-term soil productivity is maintained within a multi-rotation SRC system, given the rapid growth rate and associated nutrient exports offsite when harvesting the willow biomass after repeated short rotations. Based on early results from the first willow SRC rotation, it was found willow systems are relatively low nutrient-demanding, with minimal nutrient output other than in harvested biomass. The overall aim of this manuscript is to summarize the literature and present findings and data from ongoing research trials across Canada and northern U.S.A. examining willow SRC system establishment and viability. The research areas of interest presented here are the crop production of willow SRC systems, above- and below-ground biomass dynamics and the C budget, comprehensive soil-willow system nutrient budget, and soil nutrient amendments (via fertilization) in willow SRC systems. Areas of existing research gaps were also identified for the Canadian context

Organic Carbon Accumulation in Topsoil Following Afforestation with Willow: Emphasis on Leaf Litter Decomposition and Soil Organic Matter Quality

Short-rotation intensive cultures (SRICs) of willows can potentially sequester carbon (C) in soil. However, there is limited information regarding the factors governing soil organic C (Corg) accumulation following afforestation. The objectives of this study were to: (i) determine whether willow leads to Corg accumulation in the topsoil (0–10 cm) two to six years after establishment in five SRICs located along a large climatic/productivity gradient in southern Quebec, and (ii) assess the influence of leaf litter decomposition and soil organic matter (OM) quality on Corg accumulation in the topsoil. Topsoil Corg concentrations and pools under SRICs were, on average, 25% greater than reference fields, and alkyls concentrations were higher under SRICs. On an annualized basis, Corg accumulation rates in the topsoil varied between 0.4 and 4.5 Mg ha−1 yr−1. Estimated annual litterfall C fluxes were in the same order of magnitude, suggesting that SRICs can accumulate Corg in the topsoil during early years due to high growth rates. Leaf litter decomposition was also related to Corg accumulation rates in the topsoil. It was positively correlated to growing season length, degree-days, and growing season average air and topsoil temperature (r > 0.70), and negatively correlated to topsoil volumetric water content (r = −0.55). Leaf litter decomposition likely occurred more quickly than that of plants in reference fields, and as it progressed, OM became more decay resistant, more stable and accumulated as Corg in the topsoil

Maximum Annual Potential Yields of Salix miyabeana SX67 in Southern Quebec and Effects of Coppicing and Stool Age

Aboveground biomass yields of short rotation cultures (SRC) of willow can vary substantially depending on site quality. Among others, aboveground biomass yields depend on climatic conditions, soil properties, age of the SRC, and number of harvesting cycles. In this study, we investigated the effects of coppicing on growth variables (i.e., largest basal stem, height, and aboveground biomass) at ten SRC of Salix miyabeana SX67 established on various soils in southern Quebec. More than 1100 shrubs with stool ages varying between 1 and 15 years were measured. Strain analysis was carried out to calculate past annual aboveground productivities, and maximum annual yield potential was quantified at each site. Annual growth rates were highly variable and depended on site and coppicing history. To achieve optimal stool development and aboveground yields, two to three growing seasons following coppicing were necessary for sandy and clayey sites, respectively. The delays for reaching maximum yields were shortened when soil cation exchange capacity was dramatically low and were prolonged when soil was physically restricting stool development. This lag influenced the total yield of the first rotation and also modulated the magnitude of the increase of aboveground biomass that is generally observed in the second rotation. To increase yields in southern Quebec, our results suggest that it is preferable to extend the length of the first rotation instead of coppicing at the end of the first growing season after establishment