Science

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Now showing 1 - 10 of 22
  • (2006) Heness, Gregory; Tam, W.; Bandyopadhyay, Srikanta
    Conference Paper
    A binary system of nano-reinforcement was used to increase flexural strength, flexural modulus and impact strength of a bisphenol-A type epoxy resin. Montmorillonite and alumina particles were used as modifiers. Each modifier, by itself, was found to increase these properties and further the use of both was found to have a synergistic effect.

  • (2006) Burton, Michael
    Conference Paper
    Dome C, being one of the summits of the Antarctic plateau, is an exceptional site for astronomy. Its advantages over a temperate-latitude site for a wide range of observations are considerable, as well as becoming increasingly appreciated by the scientific community. We discuss what these advantages are, and some of the science possibilities they offer. They fall under four principal regimes: (i) diffraction-limited observations (i.e. ? > 3 ?m), (ii) wide-field thermal infrared observations (i.e. ? > 2.2 ?m), (iii) when observations are seeing-limited (i.e. from 0.4-3 ?m) and (iv) new windows (i.e. in the mid-IR and submm). Each regime offers particular advantages over corresponding observations made from a temperate site. When more than one of these advantages applies the gains can be potent. The science possibilities are many, ranging from solar system science, such as monitoring the global climate of Mars and Venus, to the study of the distant universe, such as ultra-deep fields to probe the assembly process of galaxies and the search for the `first light` through thermal-IR emission from gamma ray bursters. In this paper we discuss a range of science opportunities offered by each of these regimes, making use of a 2 m-class telescope. Such a facility would serve as an essential next step in the development of Antarctic astronomy, and the far-reaching possibilities offered by larger telescopes and interferometers on the Antarctic plateau. © EAS, EDP Sciences 2007.

  • (2007) Storey, John; Lawrence, Jonathan; Ashley, Michael; Burton, Michael
    Conference Paper
    PILOT is proposed as a partnership between Australia and Europe to develop a 2.4 m optical/infrared telescope for Dome C, Antarctica. Funding for a detailed designed study is being sought from Australian sources, with a view to commencing construction in early 2008. The current `strawman` design is for an f/10 dual Nasmyth configuration with provision for both a silicon carbide fast tip-tilt secondary mirror for the thermal infrared, and an adaptive secondary mirror to achieve diffraction-limited imaging at wavelengths as short as V-band. © EAS, EDP Sciences 2007.

  • (2002) Travouillon, Tony; Ashley, Michael; Burton, Michael; Calisse, Paolo; Lawrence, Jonathan; Storey, John; Everett, Jon
    Conference Paper
    Observing conditions at the South Pole have probably been better characterised than at any other site on earth. The benefits are now well established, and include greatly reduced near- and mid-infrared sky brightness, improved atmospheric transmission, and a unique atmospheric turbulence profile with almost zero turbulence above the lowest 200 metres of the atmosphere. The site testing work is still in progress, with a view to better understanding the residual infrared sky emission and the nature of the atmospheric turbulence. Autonomous experiments are now also currently operating at Dome C. Plans are well advanced to extend these experiments, and to study even higher altitude sites such as Vostok and Dome A. In this paper, we report the recent results from UNSW. More comprehensive reviews can be found in the literature.

  • (2008) Dechsakulthorn, F.; Pattanamahakul, P.; Hayes, A.; Khalil, Christian; Winder, C.
    Conference Paper

  • (2006) Bandyopadhyay, Srikanta; Zeng, Qinghua; Berndt, Christopher C.; Rizkalla, Sami; Gowripalan, N.; Matisons, Janis
    Conference Paper
    The topics of ACUN-5 will cover all aspects of the science and technology of composite materials, from materials fabrication, processing, manufacture, structural and property characterisation, theoretical analysis, modelling and simulation, materials design to a variety of applications, such as aerospace, automotive, infrastructure, packaging, ship-building, and recreational products. ACUN-5 will bring together the latest research and developments of the complete range of composite materials, including biocomposites, medical-composites, functional and smart composites, gradient and layered composites, nanocomposites, structural composites and mimicking natural materials. The reinforcements will range from nano-, micro-, meso- to macro-scale in polymer, metal, ceramic and cementitious matrices.

  • (2001) Wolfe, Joseph; Smith, John; Fletcher, Neville; McGee, Terry
    Conference Paper
    The Baroque and early Classical flutes have six finger holes that are small enough to be covered by the unaided fingers, and also positioned so as to allow this. They have a partly conical bore, which is narrower than that of the Boehm flute. We compare these instruments in terms of their sound spectra and intonation, and we explain some of the features of these in terms of their acoustic impedance. Because flutes are open at the air jet, the minima in impedance are of greatest interest. The Classical and Baroque instruments have impedance minima whose depths decrease more rapidly with increasing frequency than those of the Boehm flute. This is attributed to the narrower bore and the consequently greater wall losses, and is one reason for the darker timbre of these instruments. In most fingerings, the effect of a series of open holes is to produce a ’cut off filter’, which reduces the depth of higher minima. This occurs at lower frequency for the Classical and Baroque flutes, because of the smaller and fewer tone holes. We also report the effects of cross fingerings, and the effects of the differing hole sizes required by the comfortable placing of tone holes. The frequency dependence of the end effects produced by cross fingering leads to inharmonicities in the impedance minima, which in part explains why notes produced with these fingerings have darker timbre than those produced with simple fingerings.

  • (2001) Wolfe, Joseph; Smith, John; Fletcher, Neville; Hollenberg, Lloyd
    Conference Paper
    The Australian didjeridu is a deceptively simple instrument acoustically but, because it is closely coupled to the player's vocal tract without an intervening mouthpiece, a skilled player can produce a wide variety of striking musical effects. Measurements and supporting theory elucidate the roles of passive instrument acoustics, lip motion, controllable vocal tract resonances, and active vocalisation.

  • (2006) Storey, John; Lawrence, Jonathan; Ashley, Michael; Burton, Michael; Angel, Roger; Hinz, Phil
    Conference Paper
    We present a proposal for an 8.4 metre off-axis optical/IR telescope to be located at Dome C, Antarctica. LAPCAT will use a mirror identical to the offset segment recently cast for the Giant Magellan Telescope (GMT) as a completely unobscured f/2.1 primary. With a cooled deformable Gregorian secondary in a dewar following prime focus, LAPCAT will allow for diffraction-limited imaging with only a single reflecting surface at [similar to] 220K, and thus the lowest possible thermal background obtainable on earth. The exceptionally low atmospheric turbulence above Dome C enables very high contrast imaging in the thermal infrared, and diffraction limited imaging extending to optical wavelengths (20 mas at 800 nm, where Strehl ratios > 60% are projected). As an example, a deep 5 ?m exoplanet imaging survey to complement current radial velocity methods could take advantage of both the low background and pupil remapping methods for apodization enabled by the clear aperture. Many new, young, giant planets ( greater than or equal 3Mj at 1 Gyr) would be detected in orbits greater than or equal 5 AU out to 20 pc. By providing a test bed for many of the GMT technologies in an Antarctic environment, LAPCAT also paves the way for the eventual construction of a second GMT at Dome C. Such a telescope would have unparalleled capabilities compared both to other ELTs in temperate sites and to JWST.

  • (2006) Gong, S; Bandyopadhyay, Srikanta
    Conference Paper
    Correlations between mechanical properties and microscopic features were investigated using both unnotched and notched specimens of rubber-toughened PMMA materials in very low to medium range of cross head speeds. It is found that: (1) significant difference in fracture surface morphologies between pure PMMA and rubber-toughened PMMA of unnotched specimens can be correlated with their difference in modes of failure; and variation of degree of roughness in rubber toughened PMMA can be correlated with variation of Young's modulus which is affected by rubber content; (2) decreasing trend of crack initiation region with increasing speed in notched specimens correlates with that of fracture elongation; and decreasing trend of stress whitening zone in notched specimens with both increasing speed and decreasing rubber content correlates with that of calculated plastic zone and the trend correlates also with that in modulus of toughness.