Critical flow and pressure ratio data for LOX flowing through nozzles

LOX and LN2 data for two-phase critical flow through nozzles were acquired with precision control. The principal measured parameters were inlet conditions, critical flow rate and critical flow pressure ratio. It is conclusively demonstrated that the principle of corresponding states can be applied to two-phase choked flow through nozzles. It is also shown that the proper normalizing parameters are developed, and that current theories can provide an adequate means for extrapolating data to other fluids

Two-phase choked flow of subcooled oxygen and nitrogen

Data are presented for two-phase critical flow through nozzles. Test results from two converging-diverging nozzles and two separate test facilities are in excellent agreement. The critical flow rate and critical flow pressure ratio data conclusively demonstrate that the principle of corresponding states can be applied to two-phase choked flow through nozzles. Normalizing parameters were developed to correlate these data, and current theories can provide an adequate means for extrapolating to other fluids. Such information can be useful for cryogenic fluid storage applications

Characterization of a high-pressure diesel fuel injection system as a control technology option to improve engine performance and reduce exhaust emissions

Test results from a high pressure electronically controlled fuel injection system are compared with a commercial mechanical injection system on a single cylinder, diesel test engine using an inlet boost pressure of 2.6:1. The electronic fuel injection system achieved high pressure by means of a fluid intensifier with peak injection pressures of 47 to 69 MPa. Reduced exhaust emissions were demonstrated with an increasing rate of injection followed by a fast cutoff of injection. The reduction in emissions is more responsive to the rate of injection and injection timing than to high peak injection pressure

Spatially Offset Active Galactic Nuclei III: Discovery of Late-Stage Galaxy Mergers with The Hubble Space Telescope

Galaxy pairs with separations of only a few kpc represent important stages in the merger-driven growth of supermassive black holes (SMBHs). However, such mergers are difficult to identify observationally due to the correspondingly small angular scales. In Paper I we presented a method of finding candidate kpc-scale galaxy mergers that is leveraged on the selection of X-ray sources spatially offset from the centers of host galaxies. In this paper we analyze new Hubble Space Telescope (HST) WFC3 imaging for six of these sources to search for signatures of galaxy mergers. The HST imaging reveals that four of the six systems are on-going galaxy mergers with separations of 1.2-6.6 kpc (offset AGN). The nature of the remaining two spatially offset X-ray sources is ambiguous and may be associated with super-Eddington accretion in X-ray binaries. The ability of this sample to probe small galaxy separations and minor mergers makes it uniquely suited for testing the role of galaxy mergers for AGN triggering. We find that galaxy mergers with only one AGN are predominantly minor mergers with mass ratios similar to the overall population of galaxy mergers. By comparison, galaxy mergers with two AGN are biased toward major mergers and larger nuclear gas masses. Finally, we find that the level of SMBH accretion increases toward smaller mass ratios (major mergers). This result suggests the mass ratio effects not only the frequency of AGN triggering but also the rate of SMBH growth in mergers.Comment: 15 pages, 7 figures, accepted for publication in The Astrophysical Journa

Baseline performance and emissions data for a single-cylinder, direct-injected diesel engine

Comprehensive fuel consumption, mean effective cylinder pressure, and emission test results for a supercharged, single-cylinder, direct-injected, four-stroke-cycle, diesel test engine are documented. Inlet air-to-exhaust pressure ratios were varied from 1.25 to 3.35 in order to establish the potential effects of turbocharging techniques on engine performance. Inlet air temperatures and pressures were adjusted from 34 to 107 C and from 193 to 414 kPa to determine the effects on engine performance and emissions. Engine output ranged from 300 to 2100 kPa (brake mean effective pressure) in the speed range of 1000 to 3000 rpm. Gaseous and particulate emission rates were measured. Real-time values of engine friction and pumping loop losses were measured independently and compared with motored engine values

WTG Energy Systems' Rotor: Steel at 80 Feet

The design, specifications, and performance of the 80 foot diameter fixed pitch rotor operating on the MP1-200 wind turbine generator installed as part of the Island of Cuttyhunk's electric power utility grid system are described. This synchronous generating system rated 200 kilowatts at 28 mph wind velocity, and produces constant 60 Hz, 480 VAC current at +/- 1 percent accuracy throughout the machine's operating range. Future R & D requirements and suggestions are included with cost data

The Origin of Double-Peaked Narrow Lines in Active Galactic Nuclei III: Feedback from Biconical AGN Outflows

We apply an analytic Markov Chain Monte Carlo model to a sample of 18 AGN-driven biconical outflows that we identified from a sample of active galaxies with double-peaked narrow emission lines at z < 0.1 in the Sloan Digital Sky Survey. We find that 8/18 are best described as asymmetric bicones, 8/18 are nested bicones, and 2/18 are symmetric bicones. From the geometry and kinematics of the models, we find that these moderate-luminosity AGN outflows are large and energetic. The biconical outflows axes are randomly oriented with respect to the photometric major axis of the galaxy, implying a randomly oriented and clumpier torus to collimate the outflow, but the torus also allows some radiation to escape equatorially. We find that 16/18 (89%) outflows are energetic enough to drive a two-staged feedback process in their host galaxies. All of these outflows geometrically intersect the photometric major axis of the galaxy, and 23% of outflow host galaxies are significantly redder or have significantly lower specific star formation rates when compared to a matched sample of active galaxies.Comment: 32 pages, 11 figures, accepted for publication in MNRAS; See Figure 7 for a summary of the finding