• Title/Summary/Keyword: Chris

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Relativistic Hydrodynamics and Quasiperiodic Oscillations

  • MATHEWS GRANT J.;FRAGILE P. CHRIS;WILSON JANES R.
    • Journal of The Korean Astronomical Society
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    • v.34 no.4
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    • pp.265-269
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    • 2001
  • We present preliminary numerical simulations of tilted-disk accretion around a rotating black hole. Our goal is to explore whether hydrodynamic instabilities near the Bardeen-Petterson radius could be responsible for generating moderate-frequency quasi-periodic oscillations in X-ray binaries. We review the relevant general relativistic hydrodynamic equations, and discuss preliminary results on the structure and dynamics of a thin, Keplerian disk.

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THE LONG BASELINE ARRAY

  • EDWARDS, PHILIP G.;PHILLIPS, CHRIS
    • Publications of The Korean Astronomical Society
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    • v.30 no.2
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    • pp.659-661
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    • 2015
  • The Long Baseline Array is an array of radio telescopes using the technique of Very Long Baseline Interferometry to achieve milli-arcsecond-scale angular resolution. The core telescopes are located in Australia, with telescopes in New Zealand and South Africa also participating regularly. In this paper the capabilities of the Long Baseline Array are described, and examples of the science undertaken with the array are given.

New Zealand National and Regional State of the Environment Aquifer Reporting

  • Davidson, Peter;Daughney, Chris
    • Proceedings of the Korea Water Resources Association Conference
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    • 2010.05a
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    • pp.102-110
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    • 2010
  • Central and regional government agencies collaborate to monitor and report on the quality of New Zealand's groundwater resources. Measurements from around 1,100 water wells representing the main economic aquifers are collected each season and used to prepare regional or national reports on its state, and trends over time. New Zealand's groundwater quality is of a relatively high standard by international standards, but is influenced by human activities and can also be affected by naturally occurring degrading processes.

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Enhanced Machinability of Sinter-hardenable PM Steels

  • Lindsley, Bruce;Schade, Chris;Fillari, George
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09a
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    • pp.299-300
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    • 2006
  • Machining of sinter-hardened PM steels provides a challenge for part makers. To facilitate machining of these materials, a new additive (MA) has been developed to increase tool life during the machining process. Hard turning tests were performed to evaluate the effect of this new additive. Sintered compacts with the MA additive were compared to compacts without a machining aid and to compacts that contained the MnS additive. This paper discusses the improvement in machinability with this new additive in sinter-hardenable PM steels.

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AKARI DEEP FIELD SOUTH: SPECTROSCOPIC OBSERVATIONS OF INFRARED SOURCES

  • Sedgwick, Chris;Serjeant, Stephen;Pearson, Chris;Matsuura, Shuji;Shirahata, Mai;Matsuhara, Hideo;Marchetti, Lucia;White, Glenn J.;Vaccari, Mattia;Baronchelli, Ivano;Rodighiero, Giulia;Hadsukade, Bunyo;Clements, David L.;Amber, Simon
    • Publications of The Korean Astronomical Society
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    • v.32 no.1
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    • pp.281-285
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    • 2017
  • We present a summary of our spectroscopic redshift catalogue of 404 sources in the AKARI Deep Field South (ADF-S). We have used the AAOmega spectrograph to target mid-infrared and far-infrared sources selected primarily from AKARI observations in this field for which we were able to obtain optical counterparts. Our sources with identified redshifts include 316 with $H{\alpha}$ detections at $z{\leq}0.345$ and 15 sources at z > 1 with MgII or $Ly{\alpha}$ emission lines. About 13% of our $z{\leq}0.345$ sources are dominated by active galactic nuclei (AGN) emission, although many show emission from both star formation and AGNs. The median Balmer decrement is 5.9. Ultra-luminous infrared galaxies (ULIRGs) were found only in the higher-redshift sources. Optical and near infrared data will be available shortly, enabling calibration of the line luminosities and spectral energy distribution (SED) fitting for these sources.