Researchers worldwide view the high theoretical specific energy of the lithium-air or lithium-oxygen battery as a promising path to a transformational energy-storage system for electric vehicles. Here, we present a self-consistent material-to-system analysis of the best-case mass, volume, and cost values for the nonaqueous lithium-oxygen battery and compare them with current and advanced lithium-based batteries using metal-oxide positive electrodes. Surprisingly, despite their high theoretical specific energy, lithium-oxygen systems were projected to achieve parity with other candidate chemistries as a result of the requirement to deliver and purify or to enclose the gaseous oxygen reactant. The theoretical specific energy, which leads to predictions of an order of magnitude improvement over a traditional lithium-ion battery, is shown to be an inadequate predictor of systems-level cost, volume, and mass. This analysis reveals the importance of system-level considerations and identifies the reversible lithium-metal negative electrode as a common, critical high-risk technology needed for batteries to reach long-term automotive objectives. Additionally, advanced lithium-ion technology was found to be a moderate risk pathway to achieve the majority of volume and cost reductions. Broader contextThe commercialization of battery electric vehicles has provided a glimpse of one potential future paradigm of the transportation sector. Moving to an electricitybased transportation system could enable a domestically produced, potentially near-zero emission energy source if coupled to clean, domestic sources of electricity production. However, the batteries used in electric vehicles in 2013 are too expensive, large, and heavy for mass market adoption; signicant progress is needed. The lithium-air or lithium-oxygen battery is a high visibility archetype for the "best-case" possible electrochemical energy-storage system for electric vehicles. We present a material-to-systems analysis of the lithium-oxygen chemistry with comparison to current and future lithium-based chemistries to identify scientic challenges and technological possibilities. Through translation of materials-level science to the systems-level engineering, we show that a lithiumoxygen battery system for automotive applications has comparable cost, volume, and mass to other advanced chemistries that are in more mature states of development and have less technical risk. This result demonstrates that system-level analysis is necessary and may contradict trends predicted from active materials based specic energy and energy density calculations that are the basis for many research investment decisions.

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The axial and swirl velocity and turbulence profiles downstream of a small-scale combustor were measured using a Laser Doppler Velocimeter. The effects of combustor geometry (nozzle swirl and liner mixing and dilution holes), operating conditions (mass flow and pressure) and combustion were independently examined. For the combustion tests, the combustor exit temperature profiles were also measured with an insertion thermocouple. The normalized velocity profiles showed no effect of mass flow, pressure or overall velocity on the combustor exit profiles. For the low-swirl fuel nozzle, levels of turbulence were fairly constant without or with combustion. However, with the high-swirl fuel nozzle, the level of swirl decreased as the firing temperature increased (to conserve angular momentum). The effect of swirl reduction could also be seen in the turbulence levels which also decreased. This showed that the mean swirl was generating much of the turbulence. It was also found from testing various combustor geometries that the dilution jets significantly disrupted and thereby reduced the level of swirl exiting from the combustor.

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An implantable artificial kidney using a hemofilter constructed from an array of silicon membranes to provide ultrafiltration requires a suitable blood flow path to ensure stable operation in vivo. Two types of flow paths distributing blood to the array of membranes were evaluated: parallel and serpentine. Computational fluid dynamics (CFD) simulations were used to guide the development of the blood flow paths. Pressure data from animal tests were used to obtain pulsatile flow conditions imposed in the transient simulations. A key consideration for stable operation in vivo is limiting platelet stress accumulation to avoid platelet activation and thrombus formation. Platelet stress exposure was evaluated by CFD particle tracking methods through the devices to provide distributions of platelet stress accumulation. The distributions of stress accumulation over the duration of a platelet lifetime for each device revealed that stress accumulation for the serpentine flow path exceeded levels expected to cause platelet activation while the accumulated stress for the parallel flow path was below expected activation levels.

Abstract. The behavior of supersonic mixing layers under three x conditions has been examined by schlieren photography and laser y Doppler velocimetry. In the schlieren photographs, some largeYo scale, repetitive patterns were observed within the mixing layer; ( however, these structures do not appear to dominate the mixing layer character under the present flow conditions. It was found that 7 higher levels of secondary freestream turbulence did not increase the b peak turbulence intensity observed within the mixing layer, but slightly increased the growth rate. Higher levels of freestream turbu-~/ lence also reduced the axial distance required for development of the 0 mean velocity. At higher convective Mach numbers, the mixing # layer growth rate was found to be smaller than that of an incompressible mixing layer at the same velocity and freestream density a ratio. The increase in convective Mach number also caused a de~b crease in the turbulence intensity (a./A U).

The behavior of supersonic mixing layers under three x conditions has been examined by schlieren photography and laser y Doppler velocimetry. In the schlieren photographs, some large-Yo scale, repetitive patterns were observed within the mixing layer;( ) however, these structures do not appear to dominate the mixing layer character under the present flow conditions. It was found that 7 higher levels of secondary freestream turbulence did not increase the 6 peak turbulence intensity observed within the mixing layer, but slightly increased the growth rate. Higher levels of freestream turbu-~/ lence also reduced the axial distance required for development of the 0 mean velocity. At higher convective Mach numbers, the mixing Ft layer growth rate was found to be smaller than that of an incom-0 pressible mixing layer at the same velocity and freestream density a ratio. The increase in convective Mach number also caused a de-~b crease in the turbulence intensity (%/A U).