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The main petroleum product transported through pipelines in Canada is diluted bitumen (dilbit), a semi-liquid form of heavy crude oil mixed with natural gas condensates to facilitate transport. The weathering, fate, behaviour, and environmental effects of dilbit are crucial to consider when responding to a spill, however few environmental studies on dilbit have been completed. Here we report on 11-day long experimental spills of dilbit (Cold Lake Winter Blend) in outdoor micro-cosms meant to simulate a low-energy aquatic system containing natural lake water and sedi-ments treated with a low (1:8,000 oil:water) and high (1:800 oil:water) volume of dilbit. In the first 24 hours of the experiment, volatile hydrocarbons quickly evaporated from the dilbit, result-ing in increased dilbit density and viscosity. These changes in dilbit’s physical and chemical properties ultimately led to its submergence after 8 days. We also detected rapid accumulation of polycyclic aromatic compounds in the water column of the treated-microcosms following the spills. Our study provides new information on the environmental fate and behaviour of dilbit in a freshwater environment that will be critical to environmental risk assessments of proposed pipe-line projects. In particular, our study demonstrates the propensity for dilbit to sink under ambient environmental conditions in fresh waters typical of many boreal lakes.

We studied 2011 cycling mode share at the census-tract level in Montréal and Vancouver, Canadian cities with relatively high mode shares and diverse bike infrastructure. We examined whether mode share variability, for all commuters and male and female commuters separately, was related to proximity to any bikeway, proximity to four bikeway types, slopes on routes to bikeways, or commute times. Cycling mode shares at the census-tract level varied from 0 to 20.4%. About a third of cycle commuters were female, but this proportion approached parity with males in census tracts with mode shares of 7% and higher. A one-kilometer closer proximity to any bikeway was associated with four times higher cycling mode share. Proximity to cycle tracks was associated with higher cycling mode shares in both cities. Other bikeway types did not have similar associations in the two cities, and the pattern of results suggested that the networks formed may have been more important than specific bikeway characteristics. Uphill slopes to bikeways were associated with somewhat lower mode shares in bivariate analyses but not in adjusted models. Cycle commuting was most common in neighborhoods with intermediate average commute durations: 20 to 29 minutes. Our results suggest that cycle tracks and bikeways that form a connected network are associated with higher neighborhood cycling commute mode shares. These features appeared even more important to women, and their cycling (or not) was strongly related to overall cycling mode shares.

Datacenters provide the infrastructure for cloud computing services used by millions of users everyday. Many such services are distributed over multiple datacenters at geographically distant locations possibly in different continents. These datacenters are then connected through high speed WAN links over private or public networks. To perform data backups or data synchronization operations, many transfers take place over these networks that have to be completed before a deadline in order to provide necessary service guarantees to end users. Upon arrival of a transfer request, we would like the system to be able to decide whether such a request can be guaranteed successful delivery. If yes, it should provide us with transmission schedule in the shortest time possible. In addition, we would like to avoid packet reordering at the destination as it affects TCP performance. Previous work in this area either cannot guarantee that admitted transfers actually finish before the specified deadlines or use techniques that can result in packet reordering. In this paper, we propose DCRoute, a fast and efficient routing and traffic allocation technique that guarantees transfer completion before deadlines for admitted requests. It assigns each transfer a single path to avoid packet reordering. Through simulations, we show that DCRoute is at least 200 times faster than other traffic allocation techniques based on linear programming (LP) while admitting almost the same amount of traffic to the system. 23rd IEEE International Conference on High Performance Computing (HiPC)

Subroutine to calculate soil modulus as a as a power function of the confining stresses

Transportation systems are growing and complex systems. The presence of multiple, correlated, dynamically changing elements in this system with dependence and feedback add further complexity to the problem. In this paper, we present an integrated approach based on system dynamics (SD) simulation and analytic network process (ANP) for evaluating sustainable transport policies. Five policies namely trip sharing (TRS), trip rate reduction (TRR), reducing the length of the road network (LRN), car ownership (CAO), and average kilometres travelled (AKT) are evaluated against three criteria namely congestion level (CONG), fuel consumption (FULC), and emission (EMIS). The data for the policies is generated via system dynamics simulation. ANP is used to rank the evaluation criteria and the alternatives (sustainable transportation policies). A numerical study is provided. The results of our study reveal that trip sharing based policies perform better in comparison to the other policies for achieving sustainability in a transportation system.