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The unprecedented nature of the Deepwater Horizon oil spill required the application of research methods to estimate the rate at which oil was escaping from the well in the deep sea, its disposition after it entered the ocean, and total reservoir depletion. Here, we review what advances were made in scientific understanding of quantification of flow rates during deep sea oil well blowouts. We assess the degree to which a consensus was reached on the flow rate of the well by comparing in situ observations of the leaking well with a time-dependent flow rate model derived from pressure readings taken after the Macondo well was shut in for the well integrity test. Model simulations also proved valuable for predicting the effect of partial deployment of the blowout preventer rams on flow rate. Taken together, the scientific analyses support flow rates in the range of ∼50,000–70,000 barrels/d, perhaps modestly decreasing over the duration of the oil spill, for a total release of ∼5.0 million barrels of oil, not accounting for BP's collection effort. By quantifying the amount of oil at different locations (wellhead, ocean surface, and atmosphere), we conclude that just over 2 million barrels of oil (after accounting for containment) and all of the released methane remained in the deep sea. By better understanding the fate of the hydrocarbons, the total discharge can be partitioned into separate components that pose threats to deep sea vs. coastal ecosystems, allowing responders in future events to scale their actions accordingly.

Particle flows of high particle concentration are important in many fields, including chemical processing, pharmaceutical processing, energy conversion and powder transport. However, despite decades of research and industrial application, the real time behavior of particle flow fields is still not well understood. One of the main reasons is that experimental data is difficult to acquire in such harsh, opaque particle flow environments. In this educational video for the Gallery of Fluid Motion, high speed video acquired with a new, patented high speed particle imaging velocimetry (high speed PIV) technology is presented. This technology was developed by the USDOE National Energy Technology Laboratory (NETL). It is being applied to observe and measure the real time behavior of individual particle motion inside particle flow fields of high particle concentration for the first time. The high speed PIV system records high speed videos of particle motion with excellent spatial and temporal clarity. The high speed videos are analyzed to measure the concentration and the two-dimensional motion (velocity and trajectory) of individual particles. Data sample rates for velocity vectors are in the range of 0.1 to 3 million vectors per second, thereby providing full resolution of the temporal domain of particle velocity. To see and measure particle motion inside the flow fields at high particle concentrations, a custom borescope is inserted into particle flow fields. The particle tracking technique can measure gas and fluid flow if the particles are small enough (have a low enough Stokes number) to follow the gas/fluid flow. In areas of rapid mixing, such as turbulent wakes, particle tracking can provide better spatial resolution that conventional cross-correlation based PIV analysis. Keywords: fluid dynamics video, particle tracking, fluidization

Nothing in American railroading matched the excitement of a busy union station with its vividly colored streamliners from many railroads. Shaffer takes a look at how these stations worked, with an eye toward adapting the action to a model railroad. He then studies the complete operations of a prototype four-tracked terminal, where one train each 20 minutes kept switch tenders and yard engineers busy 18 hours a day.

Shaffer looks at the operation of what was once one of the hottest passenger operations on the Baltimore & Ohio, the four-tracked, stub terminal at Smithfield Street in Pittsburgh. The station opened in 1889 and was modernized and expanded in 1915. Smithfield Street's importance began to dwindle in late 1934 when the B&O switched its mainline traffic onto Pittsburgh & Lake Erie tracks between McKeesport and New Castle to avoid the backing up maneuver necessitated by the stub terminal.