Fast simulation of transient temperature distributions in power modules using multi-parameter model reduction

In this study, a three-dimensional model with multi-parameter order reduction is applied to the thermal modelling of power electronics modules with complex geometries. Finite element or finite difference method can be used to establish accurate mathematical models for thermal analyses. Unfortunately, the resulting computational complexity hinders the analysis in parametric studies. This study proposes a parametric order reduction technique that can significantly increase simulation efficiency without significant penalty in the prediction accuracy. The method, based on the block Arnoldi method, is illustrated with reference to a multi-chip SiC power module mounted on a forced air-cooled finned heat sink with a variable mass flow rate

A First Assessment of the Elemental Composition of Atmospheric Aerosols in the Canadian Oil Sands Region

Canadian Oil Sands, which comprise 97% of Canada’s 176 billion barrels of proven oil reserves, are located beneath 140,200 km2 of boreal forests, prairies and wetlands, and are the second largest known deposit of crude oil in the world. As such, this region has experienced rapid industrial development, which resulted also in increasing industrial air emissions, primarily from bitumen upgrading and mine vehicle fleet operations. This rapid development has led to concerns regarding health risk to humans, and other terrestrial and aquatic wildlife associated with exposure to toxic contaminants, especially metals and polycyclic aromatic compounds (PACs) particularly along the Athabasca River and its watershed. Canada’s Minister of the Environment announced that Environment Canada (EC) will jointly lead, in collaboration with Government of Alberta and relevant stakeholders, the development and implementation of an enhanced monitoring system in the Oil Sands region to provide information on the state of the air, water, land andbiodiversity. This work presents preliminary data on the first assessment of elemental composition of fine particulate matter (particles<2.5 mm in diameter; PM2.5) at 3 air quality sites in close proximity to Oil Sands processing activities. Since December 2010, integrated 24 hour air samples were collected every sixth day on a 47-mm Teflon filters using Thermo Fisher Partisol 2000-FRM samplers operated by the National Air Pollution Surveillance (NAPS) network that involves EC and the Canadian provinces and territories. All samples including laboratory, travel and field blanks were subjected to gravimetric determination of PM2.5 mass and energy dispersive X-ray fluorescence (ED-XRF) analysis for 46 elements. Since ED-XRF is a non-destructive technique, PM2.5 samples were subsequently analyzed for 37 trace elements including rare earth elements using inductively-coupled plasma mass spectrometry (ICP-MS) combined with microwave-assisted acid digestion. The resulting data will be discussed

First order optimization technique for interferometric optical waveguide sensors

A novel approach of a first order optimization technique applicable to design process of photonic sensing devices and waveguide geometries is presented. The application of the optical field sensitivity mapping technique enables first order optimization of geometrical parameters with the final goal of enhancing the overall device sensitivity. The technique is simple, requiring only two simulations of optical field propagation and the extraction of a sensitivity map. The method is demonstrated in a design optimization process of a realistic multi mode interference sensing device. As a result, optimization of the MMI active section length, sensing region width, and the output location was accomplished. A comparison between the optimized device and two other ones of different length showed a 10 dB higher dynamic range of the output power ratio characteristic and better linearity, demonstrating enhanced sensitivity of the final device

Low temperature plasma etching for Si3N4 waveguide applications

NRC publication: Ye