A5014521017- Astrophysics and Star Formation Studies
- Radio Astronomy Observations and Technology
- Optical Network Technologies
- Stellar, planetary, and galactic studies
- Galaxies: Formation, Evolution, Phenomena
- Superconducting and THz Device Technology
- Antenna Design and Optimization
- Photonic and Optical Devices
- Astrophysics and Cosmic Phenomena
- Fluid Dynamics and Turbulent Flows
- Semiconductor Lasers and Optical Devices
- Astronomical Observations and Instrumentation
- Atmospheric Ozone and Climate
- Molecular Spectroscopy and Structure
- Astrophysical Phenomena and Observations
- Satellite Communication Systems
- Nanofluid Flow and Heat Transfer
- Adaptive optics and wavefront sensing
- Advanced Wireless Communication Techniques
- Advanced Photonic Communication Systems
- Composite Material Mechanics
- Innovations in Concrete and Construction Materials
- Cooperative Communication and Network Coding
- Wind and Air Flow Studies
- Rheology and Fluid Dynamics Studies
Raman Research Institute
2004-2019
UNSW Sydney
2001-2009
Imperial College London
1999
Keele University
1996
University of Bath
1990-1995
Aberystwyth University
1989
University of Dundee
1985
Indian Institute of Technology Delhi
1976-1978
We present the initial results of a 3-mm spectral line survey towards 83 methanol maser selected massive star-forming regions. Here we report observations J=5-4 and 6-5 rotational transitions methyl cyanide (CH3CN) J=1-0 transition HCO+and H13CO+. CH3CN emission is detected in 58 sources (70 %) our sample). estimate temperature column density for 37 these using diagram method. The temperatures derive range from 28-166 K, are lower than previously reported temperatures, derived higher J...
We present the results of a targeted 3-mm spectral line survey towards eighty-three 6.67 GHz methanol maser selected star forming clumps observed by Purcell et al. 2006. In addition to previously reported measurements HCO+ (1 - 0), H13CO+ and CH3CN (5 4) & (6 -5), we used Mopra antenna detect emission lines N2H+ HCN 0) HNC 82/83 (99 per cent), CH3OH (2 1) 78/83 (94 cent). The molecular data have been derive virial LTE masses, rotational temperatures chemical abundances in clumps, these...
Gas deficiency in cluster spirals is well known and ram-pressure stripping considered the main gas removal mechanism. In some compact groups too reported. However, loose not yet established. Lower dispersion of member velocities lower density intra-group medium small favour tidal as process them. Recent releases data from HI Parkes all sky survey (HIPASS) catalogues nearby with associated diffuse X-ray emission have allowed us to test this notion. paper, we address following questions: (a)...
Environment plays an important role in the evolution of gas contents galaxies. Gas deficiency cluster spirals and hot intracluster medium (ICM) stripping from these galaxies is a well studied subject. Loose groups with diffuse X-ray emmision intragroup (IGM) offer intermediate environment between clusters without IGM. These bright have smaller velocity dispersion lower temperature than clusters, but higher IGM density loose emission. A single dish comparative study emission IGM, showed that...
This paper describes a simple finite-difference method to simulate and Lamb wave modes in plane metal sheets. The simulation is used predict time-domain histories of field displacements vertical the sheet at groups points on sheet. time - space data so obtained are transformed by two-dimensional FFT yield frequency wavenumber representations for comparison with mode dispersion waves. An experimental rig developed transmission reception waves metal, adjustable transducer positions axis....
We have carried out observations toward the W3 complex and G34.3+0.15 using TRAO 14 m radio telescope to examine in detail chemical variations occurring while molecular clouds evolve from prestellar H II region phase. Observations include spectral surveys of these objects between 84.7 115.6 GHz; mapping W3(OH) with emissions CS (2-1), HCN (1-0), HNC HCO+ (1-0); (2-1) emission IRS 5. Chemical model calculations are used estimate age by comparing fractional abundances detected molecules. found...
An open-source voice command interface kit has been developed by integrating software and inexpensive hardware components. The for the as a lightweight modular framework with replaceable It also provides C++ library to support development of applications on top it. usefulness is demonstrated applying it voice-steer an electric wheelchair. Three participants voice-steered wheelchair along complicated path found respond reliably. average recognition time ~ 500 ms, indicating utility near...
In this paper we extend Jones's analysis of the diffraction sound in three dimensions by a semi-infinite plane with vortex sheet attached two cases when wave equation is form for still air and convection present. It found that so far as moving medium concerned imposition or otherwise Kutta-Joukowski condition does not have much influence on scattered field away from diffracting plane; source near edge has same directionality order magnitude. On other hand, wake produces stronger than...
Abstract We have surveyed 163 southern IRAS sources in the SiO $J=2$-$1 v=1$ maser line at 86 GHz, obtaining 38 (22 new and 16 previously known) detections. These detections include 6 stars not detected OH 1612 MHz surveys, 4 assigned incorrect radial velocities. The distance reachable this survey turned out to be about kpc. local velocity dispersion near Sun were found approximately $30~\mathrm{km}~\mathrm{s}^{-1}$ for these IRAS/SiO sources. A relatively high concentration of area...
Abstract We made a survey of water-vapor maser emission for 93 AGNs with the Nobeyama 45-m and Mopra 22-m telescopes from 1999 to 2002. A megamaser was detected in Seyfert 2 galaxy, NGC 6926, at distance 80 Mpc, 2002 June. [Greenhill et al. (2003a) have also reported detection close date.] The peak flux density 110 mJy, total isotropic luminosity 340${L}_{\odot}$. shows triply peaked spectrum, suggesting an edge-on disk. narrow-line feature components $V_{\mathrm{LSR}} = 6001 \,\mathrm{km}...
The squeeze film between two rectangular plates when one has a porous facing is analyzed taking into account the anisotropic permeability and slip velocity at fluid material interface. Modified equations for calculating pressure, load carrying capacity, thickness time relations are presented. effect of interface on behavior discussed found to be important.
MIMO–STBC–OFDM systems mitigate inter symbol interference and frequency-selective fading caused by multi-path propagation in modern high-data-rate wireless communication. Error correction codes use redundancy to correct errors that still occur. No systematic analysis of their performance using a common link configuration is found the literature. We fill this gap simulation study communication link, transferring data at rate 100 Mbps. find (a) for all code rates, low-density parity-check...
Large-scale surveys are essential means to leapfrog astronomical understanding. Yet, Galaxy-wide at millimetre wavelengths rare and have not benefited much from multiple receivers that provide large instantaneous field of view. If one were a number wave receivers, how best deploy them maximize survey speed measure both point smoothly distributed emission? In this paper, we present new cross telescope configuration, Efficient Linear-array Imager, demonstrate it provides an interesting...
The solution of carrier diffusion equations typically associated with semiconductor optical devices has been achieved by combining a function expansion scheme, using the Hermite-Gauss functions as basis set, collocation numerical procedure. Results for wide range cases obtained this new scheme compare very favorably those calculated other methods. Not only is present process computationally fast and efficient, but it added attraction providing conveniently solving also nonlinear...
Abstract We present results from a spectral line survey of the young stellar object IRAS 17470-2853, undertaken to examine chemical changes during evolution hot molecular cores ultracompact HII regions. Observations were carried out with Mopra 22 m radio telescope in frequency range 86.1 92.1 GHz. A total 21 lines 9 molecules detected. Except for CH 3 CN they are all simple molecules. compare region G34.3+0.15, where surveys 80–115 GHz and 330–360 have been performed. While detected similar,...
We apply the phase-switching method of Ryle to convert single dish radio telescopes one-element interferometers and thereby accord them benefit correlation measurements, viz. measure only flux from celestial sources avoiding contributions receiver atmosphere. This application has many uses: (a) enables dishes image sky efficiently without need scan, measuring all sources, point, extended, spectral continuum, with both bolometric coherent receivers; (b) adding reliable short-spacing data...
A novel optical design for a telescope, especially suited constructing large telescopes at submillimetre to wavelengths, was proposed recently. In this paper, we present some analytical results related such optics. We show that, oblique incidence, the line focus of parabolic cylinder merely shifts by same angle in opposite direction. also derive equation defining shape mirror that converts cylindrical wavefront spherical wavefront.
Three techniques for the self-consistent solution of diffusion equation, which describes distribution carriers in semiconductor lasers and optical amplifiers, EM wave equation have been investigated. The relative merits a Jacobian tri-diagonal technique, perturbation approach transfer matrix method are identified.
Surface metrology is the key to make and retain high quality surfaces. There are many coordinate measurement methods machines measure large 3D Some are: triangulation, time-of-flight, structured-lighting, photogrammetry radio-holography. They differ in ease-of-use, economy, complexity accuracy. Some, e.g. photogrammetry, point-by-point while others, holography, a point-cloud at one go. spot-measurements others areal averages. Both radio-holography used surfaces of astronomical telescopes....