Combining Research and Education: Bioclimatic Zonation along a Canadian Arctic Transect

Scientists and students from five countries combined research and education in an investigation of bioclimatic zonation along a Canadian Arctic transect, from Amund Ringnes Island and Ellesmere Island in the north to the Daring Lake research camp at the southern edge of the tundra in Nunavut. We addressed three important needs in Arctic science: 1) to integrate education and research, 2) to provide field experiences for undergraduates, and 3) to foster international collaboration. We describe five subzones within the Arctic tundra zone. Subzones are defined by the vegetation typical of mesic environments at low elevations and the dominant growth forms of vegetation in these environments. Subzonal boundaries coincide with the northern limits of several species of woody plants with distinct upright or prostrate growth forms, and ultimately with the northern limit of woody plant species. The five subzones, A-E, from north to south, are characterized by dominant growth form: (A) cushion forb, (B) prostrate dwarf shrub, (C) hemiprostrate dwarf shrub, (D) erect dwarf shrub, and (E) low shrub.Des chercheurs et des étudiants de cinq pays ont combiné recherche et éducation dans une étude portant sur la zonation bioclimatique le long d'un transect de l'Arctique canadien, allant de l'île Amund Ringnes et de l'île d'Ellesmere au nord, au camp de recherche du lac Daring situé en bordure sud de la toundra au Nunavut (Canada). On a tenu compte de trois besoins majeurs dans la science de l'Arctique, soit ceux: 1) d'intégrer l'éducation et la recherche; 2) d'offrir aux étudiants de premier cycle des expériences sur le terrain, et 3) de promouvoir la collaboration internationale. On décrit cinq sous-zones à l'intérieur de la zone de toundra de l'Arctique. Les sous-zones sont définies par la végétation typique des milieux à régime d'humidité constant à basse altitude ainsi que par la forme de croissance dominante dans ces habitats. Les limites des sous-zones correspondent aux limites septentrionales de plusieurs espèces de plantes ligneuses ayant des formes de croissance particulières verticales ou procombantes, et en fin de compte à la limite septentrionale des espèces de plantes ligneuses. Les cinq sous-zones (A-E), établies du nord au sud, sont caractérisées par une forme de croissance dominante: A) herbe non graminéenne en coussinet; B) arbuste nain déprimé; C) arbuste nain semi-déprimé; D) arbuste nain dressé, et E) arbuste

Analysis of the effects of wall temperature swing on reciprocating internal combustion engine processes

[EN] A thermal wall temperature swing model was built to capture the transient effects of various material properties and coating layers on the intra-cycle wall temperature of an internal combustion engine. This model was used with a thermodynamic engine simulation to predict and analyze the effects of different types of in-cylinder insulation on engine performance. Coatings that allow the surface temperature to swing in response to the gas' cyclical heat flux enable approximately 1/3 of the energy that was prevented from leaving the gas during expansion to be recovered while improving volumetric efficiency. Reductions in compression work due to better volumetric efficiency and less heat transfer from the walls to the gas accounted for half of the improvements, while additional work extraction during combustion and expansion accounted for the other half. As load increases, the temperature swing and benefits derived from it also increase. NSFC improvements of 0.5% to 1% were seen with a highly swinging coating in the throttled regime for a realistic engine geometry and coating area, up to 2.5% at high loadsAndruskiewicz, P.; Najt, P.; Durrett, R.; Biesboer, S.; Schaedler, T.; Payri, R. (2018). Analysis of the effects of wall temperature swing on reciprocating internal combustion engine processes. International Journal of Engine Research. 19(4):461-473. https://doi.org/10.1177/1468087417717903S461473194Ramesh Kumar, C., & Nagarajan, G. (2012). Performance and emission characteristics of a low heat rejection spark ignited engine fuelled with E20. Journal of Mechanical Science and Technology, 26(4), 1241-1250. doi:10.1007/s12206-012-0206-0Hoffman, M. A., Lawler, B. J., Güralp, O. A., Najt, P. M., & Filipi, Z. S. (2014). The impact of a magnesium zirconate thermal barrier coating on homogeneous charge compression ignition operational variability and the formation of combustion chamber deposits. International Journal of Engine Research, 16(8), 968-981. doi:10.1177/146808741456127