Changements technologiques et rapports collectifs du travail

This paper focusses on the relationship between technological change and the labour relations system circumscribed by the Québec Labour Code. While a teleological interpretation of bargaining rights of certified associations by labour jurisdictions seems to have dealt adequately with the impact of such changes on certification, the doctrine of residual management rights, in the context of fixed-term agreements entrenched in the Québec Labour Code, appears to be, in the opinion of the author, unduly rigid and restrictive. The Freedman Report on Railway run-through and the subsequent discussions surrounding the Woods Commission Report in the 1960's, resulted in the inclusion in the Canada Labour Code of provisions pertaining to the possible adjustment, through collective bargaining, of collective agreements in the context of such technological changes. Various provisions to the same effect have subsequently been inserted in the Labour Codes of Saskatchewan, Manitoba and British-Columbia. The Report of the Beaudry Commission recently proposed that the Québec Labour Code be similary modified by the inclusion of analoguous provisions. The author suggests that a reform along the lines thus suggested is, in principle, desirable to ensure a more equitable adaptability of our legal categories to the imperatives of technological change

Finite volume analysis of reinforced concrete structure cracking using a thermo-plastic-damage model

This paper proposes modifications to the phenomenological model formulation called CDPM2, developed by Grassl et al. [1]. The proposed modifications are designed to enhance model performance with coupling to temperature effects. A very strong coupling between nonlinear elasticity, plasticity, nonlocal damage evolution and temperature gradient is used to simulate arbitrary crack propagation. The use of FVM to model solid damage is a numerical challenge. This approach presents some advantages such as: ensuring that discretization is conservative even when the geometry is changing; providing a simple formulation that can be obtained directly from a difference method; and employing unstructured meshes. Most authors have neglected the nonlinearity of concrete in the elastic domain from the start of loading to the plastic domain. In this paper we confirm that concrete rheology is not linear even under low loading. Also, since the so-called fracture energy is a key parameter needed to determine the size of cracks and how they propagate in space, we consider that the fracture energy is both material and geometrical parameter dependent. For this reason, we developed a new approach which includes adaptive mesh, nonlinear rheology and thermal effects to re-calculate fracture energy at each time step. Many authors use a constant value obtained from experiments to calculate fracture energy; others use a numerical correlation. In this study, the fracture energy parameter is not constant and can vary with temperature or/and with a change in geometry due to concrete failure. As is well known, the mesh quality of complex geometries is very important for making accurate predictions. A new meshing tool was developed using the C++ programming language. This tool is faster, more accurate and produces a high-quality structured mesh. The predictions obtained were compared to a wide variety of experimental data and showed good agreement

Étude de la biodégradation de l'acide déhydroabiétique par Bacillus psychrophilus

La rivière du Saguenay (Québec, Canada) traverse une région fortement industrialisée (v.g. alumineries, papeteries) et reçoit d'importantes quantités d'eaux usées. Les teneurs en matière organique dissoute et en fibre de cellulose en suspension provenant de 4 papeteries locales sont relativement élevées dans les eaux de la Rivière et elles sont évaluéesà 29 000 tonnes par année. En plus des eaux usées industrielles, le Saguenay reçoit de grandes quantités d'eaux d'égouts domestiques, ce qui maintient une flore bactérienne relativement abondante et diversifiée dans ses eaux de surface. Parmi la matière organique provenant des papeteries, les acides résiniques abiétique et déhydroabiétique sont très toxiques pour les organismes aquatiques. Cependant, nous avons montré qu'en utilisant une population endogène de Bacillus psychrophilus, il était possible de biodégrader l'acide déhydroabiétique (ADA), un acide résinique non chloré. Nous avons constaté qu'après 72 heures de culture, la population bactérienne oxyde plus de 92 % de l'ADA et après 96 heures, la biodégradation est compléte. La cinétique de la biodégradation de l'ADA par B. psychrophilus a été étudiée en mesurant les fluctuations des teneurs en ATP et par chromatographie en phase gazeuse. Nous pensons que cette souche bactérienne peut jouer un rôle important dans la dépollution des eaux usées des papeteries du Saguenay.The Saguenay River (Quebec, Canada) is situated in an industrialized area (aluminium smelters, papers mills) and receives a great amount of industrial wastewaters. Concentrations of dissolved organic matter and suspended cellulose fibers from the 4 local paper mills are relatively high in the waters of the Saguenay River and are evaluated at 29 000 tons per year. Moreover, the Saguenay River receives urban wastewaters and the bacterial populations in the surface waters are abundant and diversified. Among the organic matter from the paper mills, the abietic and dehydroabietic resin acids are very toxic for aquatic organisms. Yet, we found that, with endogenous populations of Bacillus psychrophilus in the decantation-basin, it was possible to oxidize the dehydroabietic acid (DHA), a non chlorinated resinic acid. It was found that after 72 hours, more than 92 % of this pollutant was oxidized. After a period of 96 hours, biodegradation was complete. The kinetics of this reaction were studied by measuring the fluctuations of the rates of ATP and by gas chromatography. We think that this bacterial species is thus probably an important microorganism controlling the toxicity of the wastewaters from the paper mills of the Saguenay