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MINERVA: SMALL PLANETS FROM SMALL TELESCOPES

  • WITTENMYER, ROBERT A.;JOHNSON, JOHN ASHER;WRIGHT, JASON;MCCRADY, NATE;SWIFT, JONATHAN;BOTTOM, MICHAEL;PLAVCHAN, PETER;RIDDLE, REED;MUIRHEAD, PHILIP S.;HERZIG, ERICH;MYLES, JUSTIN;BLAKE, CULLEN H.;EASTMAN, JASON;BEATTY, THOMAS G.;LIN, BRIAN;ZHAO, MING;GARDNER, PAUL;FALCO, EMILIO;CRISWELL, STEPHEN;NAVA, CHANTANELLE;ROBINSON, CONNOR;HEDRICK, RICHARD;IVARSEN, KEVIN;HJELSTROM, ANNIE;VERA, JON DE;SZENTGYORGYI, ANDREW
    • Publications of The Korean Astronomical Society
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    • v.30 no.2
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    • pp.665-669
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    • 2015
  • The Kepler mission has shown that small planets are extremely common. It is likely that nearly every star in the sky hosts at least one rocky planet. We just need to look hard enough-but this requires vast amounts of telescope time. MINERVA (MINiature Exoplanet Radial Velocity Array) is a dedicated exoplanet observatory with the primary goal of discovering rocky, Earth-like planets orbiting in the habitable zone of bright, nearby stars. The MINERVA team is a collaboration among UNSW Australia, Harvard-Smithsonian Center for Astrophysics, Penn State University, University of Montana, and the California Institute of Technology. The four-telescope MINERVA array will be sited at the F.L. Whipple Observatory on Mt Hopkins in Arizona, USA. Full science operations will begin in mid-2015 with all four telescopes and a stabilised spectrograph capable of high-precision Doppler velocity measurements. We will observe ~100 of the nearest, brightest, Sun-like stars every night for at least five years. Detailed simulations of the target list and survey strategy lead us to expect $15{\pm}4$ new low-mass planets.

LASER-INDUCED SOOT VAPORIZATION CHARACTERISTICS IN THE LAMINAE DIFFUSION FLAMES

  • Park, J.K.;Lee, S.Y.;Santor, R.
    • International Journal of Automotive Technology
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    • v.3 no.3
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    • pp.95-99
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    • 2002
  • The characteristics of soot vaporization induced by a high-energy Pulsed laser were studied in an ethylene-air laminar flame. A system consisting of two pulsed lasers was used for the experiments. The pulse from the first laser was used to vaporize the soot particles, and the delayed pulse from the second laser was used to measure the residual soot volume fraction. Laser-induced soot vaporization was characterized according to the initial particle size distribution. The results indicated that soot particles could not be completely vaporized simply by introducing a high intensity laser pulse. Residual soot volume fractions present after vaporization appeared to be insensitive to the initial soot particle size distribution. Since the soot vaporization effect is more pronounced in the region of high soot concentrations, this laser-induced soot vaporization technique may be a very useful tool for measuring major species in highly sooting flame.

New Multiplier for a Double-Base Number System Linked to a Flash ADC

  • Nguyen, Minh-Son;Kim, In-Soo;Choi, Kyu-Sun;Lim, Jae-Hyun;Choi, Won-Ho;Kim, Jong-Soo
    • ETRI Journal
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    • v.34 no.2
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    • pp.256-259
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    • 2012
  • The double-base number system has been used in digital signal processing systems for over a decade because of its fast inner product operation and low hardware complexity. This letter proposes an innovative multiplier architecture using hybrid operands. The multiplier can easily be linked to flash analog-to-digital converters or digital systems through a double-base number encoder (DBNE) for realtime signal processing. The design of the DBNE and the multiplier enable faster digital signal processing and require less hardware resources compared to the binary processing method.

Influence of Dislocation Substructure on Ultrasonic Velocity under Tensile Deformation

  • Kim, C.S.;Lissenden, Cliff J.;Kang, Kae-Myhung;Park, Ik-Keun
    • Journal of the Korean Society for Nondestructive Testing
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    • v.28 no.6
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    • pp.477-482
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    • 2008
  • The influence of dislocation substructure of metallic materials on ultrasonic velocity has been experimentally investigated. The test materials of pure Cu, brass (Cu-35Zn), 2.25Cr-1Mo steel, and AISI 316 with different stacking fault energy (SFE) are plastically deformed in order to generate dislocation substructures. The longitudinal wave velocit $(C_L)$ decreases as a function of tensile strain in each material. The $C_L$ of Cu-35Zn and AISI 316 decreases monotonously with tensile strain, but $C_L$ of Cu and 2.25Cr-1Mo steel shows plateau phenomena due to the stable dislocation substructure. The variation of ultrasonic velocity with the extent of dislocation damping and dislocation substructures is discussed.

ELASTIC GUIDED WAVES IN COMPOSITE PIPES

  • Cho Younho;Lee Joon-Hyun;Lee Chong Myong;Rose Joseph L.
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2004.10a
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    • pp.258-263
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    • 2004
  • An efficient technique for the calculation of guided wave dispersion curves in composite pipes is presented. The technique uses a forward-calculating variational calculus approach rather than the guess and iterate process required when using the more traditional partial wave superposition technique The formulation of each method is outlined and compared. The forward-calculating formulation is used to develop finite element software for dispersion curve calculation. Finally, the technique is used to calculate dispersion curves for several structures, including an isotropic bar, two multi-layer composite bars, and a composite pipe.

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OECD/NEA BENCHMARK FOR UNCERTAINTY ANALYSIS IN MODELING (UAM) FOR LWRS - SUMMARY AND DISCUSSION OF NEUTRONICS CASES (PHASE I)

  • Bratton, Ryan N.;Avramova, M.;Ivanov, K.
    • Nuclear Engineering and Technology
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    • v.46 no.3
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    • pp.313-342
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    • 2014
  • A Nuclear Energy Agency (NEA), Organization for Economic Co-operation and Development (OECD) benchmark for Uncertainty Analysis in Modeling (UAM) is defined in order to facilitate the development and validation of available uncertainty analysis and sensitivity analysis methods for best-estimate Light water Reactor (LWR) design and safety calculations. The benchmark has been named the OECD/NEA UAM-LWR benchmark, and has been divided into three phases each of which focuses on a different portion of the uncertainty propagation in LWR multi-physics and multi-scale analysis. Several different reactor cases are modeled at various phases of a reactor calculation. This paper discusses Phase I, known as the "Neutronics Phase", which is devoted mostly to the propagation of nuclear data (cross-section) uncertainty throughout steady-state stand-alone neutronics core calculations. Three reactor systems (for which design, operation and measured data are available) are rigorously studied in this benchmark: Peach Bottom Unit 2 BWR, Three Mile Island Unit 1 PWR, and VVER-1000 Kozloduy-6/Kalinin-3. Additional measured data is analyzed such as the KRITZ LEU criticality experiments and the SNEAK-7A and 7B experiments of the Karlsruhe Fast Critical Facility. Analyzed results include the top five neutron-nuclide reactions, which contribute the most to the prediction uncertainty in keff, as well as the uncertainty in key parameters of neutronics analysis such as microscopic and macroscopic cross-sections, six-group decay constants, assembly discontinuity factors, and axial and radial core power distributions. Conclusions are drawn regarding where further studies should be done to reduce uncertainties in key nuclide reaction uncertainties (i.e.: $^{238}U$ radiative capture and inelastic scattering (n, n') as well as the average number of neutrons released per fission event of $^{239}Pu$).