Hydro-Québec

About: Hydro-Québec is a government organization based out in Montreal, Quebec, Canada. It is known for research contribution in the topics: Electric power system & Dielectric. The organization has 2596 authors who have published 4433 publications receiving 100878 citations.

Electrochemical behaviour of tin in bicarbonate solution at pH 8

Abstract: The anodic oxidation of tin in 0.1 to 1M bicarbonate solutions at pH 8 has been studied. The process may be divided into three potential regions: (1) a short active dissolution (Tafel) region; (ii) a dissolution-precipitation region; and (iii) a large region of electrode passivity. The rate-determining step of the reaction in the active-dissolution region is attributed to the diffusion of an ionic species into the solution, the diffusing species being generated at the metal surface. In the region of the first oxidation peak, the reaction rate is controlled by diffusion of CO 3 2− species in solution. When the potential becomes more positive than −0,1 Vsce, a highly passivating (most likely SnO2) film is formed on the electrode surface.

The effect of fog parameters on the testing of artificially contaminated insulators in a fog chamber

Abstract: The paper analyzes the wetting process during the testing of artificially contaminated insulators. A calculation method is developed to determine the rate of wetting by condensation and by the collision of water droplets with the insulator surface. Series of tests show that the flashover voltage, the washing effect of fog and the leakage current all depend on the fog conditions. Different fog-generation methods (cold, warm, steam) are compared on the basis of calculations and experimental results. The paper concludes that the pollution test results for an artificially contaminated insulator depend on the fog parameters and the fog generation method. The operation of the fog chamber can be optimized by adjusting the fog parameters to achieve the minimum flashover voltage.

Heat-Pump–Assisted Drying: Recent Technological Advances and R&D Needs

Abstract: Drying is one of the most energy-intensive processes in many industries. Among other technologies, drying heat pumps help to reduce primary energy consumption as well as greenhouse gas emissions. First, this paper reviews some of the general R&D requirements and challenges for heat pumps in general. Second, based on a brief review of the drying literature and the author's experience, the paper focuses on technical integration and control-required improvements as well as on future R&D needs for drying heat pumps. It suggests more rigorous studies and increased interaction between drying, heat pump, and process control researchers and specialists at both the academia and industry levels. The main goal is to stimulate the successful application of drying heat pumps in various industrial fields.

Blood melatonin and prolactin concentrations in dairy cows exposed to 60 Hz electric and magnetic fields during 8 h photoperiods

Abstract: Two experiments were conducted to test the hypothesis that electric and magnetic field (EMF) exposure may result in endocrine responses similar to those observed in animals exposed to long days. In the first experiment, 16 lactating, pregnant Holstein cows were assigned to two replicates according to a crossover design with treatment switchback. All animals were confined to wooden metabolic cages and maintained under short day photoperiods (8 h light/16 h dark). Treated animals were exposed to a vertical electric field of 10 kV/m and a horizontal magnetic field of 30 microT (EMF) for 16 h/day for 4 weeks. In a second, similar experiment, 16 nonlactating, nonpregnant Holstein cows subjected to short days were exposed to EMF, using a similar protocol, for periods corresponding to the duration of one estrous cycle. In the first experiment, circulating MLT concentrations during the light period showed a small numerical decrease during EMF exposure (P < .05). Least-square means for the 8 h light period were 9.9 versus 12.4 pg/ml, SE = 1.3. Melatonin concentrations during the dark period were not affected by the treatment. A similar trend was observed in the second experiment, where MLT concentrations during the light period tended to be lower (8.8 pg/ml vs. 16.3 pg/ml, P < .06) in the EMF exposed group, and no effects were observed during the dark period. Plasma prolactin (PRL) was increased in the EMF exposed group (16.6 vs. 12.7 ng/ml, P < .02) in the first experiment. In the second experiment, the overall PRL concentrations found were lower, and the mean plasma PRL concentration was not affected by treatment. These experiments provide evidence that EMF exposure may modify the response of dairy cows to photoperiod.

Instream flow determination using a multiple input fuzzy‐based rule system: a case study

Abstract: The attempts made to manage water to meet human requirements should also consider the needs of freshwater species and ecosystems. There are many tools available to assess instream flow needs, one of which is the use of habitat preference models. In this study, a fuzzy approach was used for modelling habitat preferences for two life stages of Atlantic salmon (Salmo salar). Experienced fish biologists and technicians contributed to the development of fuzzy sets and fuzzy preference rules for spawning and parr habitat. Fuzzy sets were defined for water depth, velocity and substrate composition. Fuzzy preference rules for the two life stages were then defined as sets of IF-THEN rules relating the physical attributes to habitat suitability. The fuzzy suitability indices are then used to obtain weighted usable area (WUA) at different discharges and to estimate the ecologic flow required to preserve habitat. Different methods are applied to combine the membership function and rules defined by the experts. A sensitivity analysis of rules of the combined system indicated that a limited number of rules are determinant and results are highly dependent on the consequences of these rules. A modification in the consequence of these rules can significantly alter WUA estimations. It is therefore recommended to combine the knowledge of many experts in the elicitation process and to quantify the uncertainty associated with the combination of expert knowledge.