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- Andreoni, I., et al.
(författare)
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Follow Up of GW170817 and Its Electromagnetic Counterpart by Australian-Led Observing Programmes
- 2017
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Ingår i: Publications Astronomical Society of Australia. - : Cambridge University Press (CUP). - 1323-3580 .- 1448-6083. ; 34
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Forskningsöversikt (refereegranskat)abstract
- The discovery of the first electromagnetic counterpart to a gravitational wave signal has generated follow-up observations by over 50 facilities world-wide, ushering in the new era of multi-messenger astronomy. In this paper, we present follow-up observations of the gravitational wave event GW170817 and its electromagnetic counterpart SSS17a/DLT17ck (IAU label AT2017gfo) by 14 Australian telescopes and partner observatories as part of Australian-based and Australian-led research programs. We report early- to late-time multi-wavelength observations, including optical imaging and spectroscopy, mid-infrared imaging, radio imaging, and searches for fast radio bursts. Our optical spectra reveal that the transient source emission cooled from approximately 6 400 K to 2 100 K over a 7-d period and produced no significant optical emission lines. The spectral profiles, cooling rate, and photometric light curves are consistent with the expected outburst and subsequent processes of a binary neutron star merger. Star formation in the host galaxy probably ceased at least a Gyr ago, although there is evidence for a galaxy merger. Binary pulsars with short (100 Myr) decay times are therefore unlikely progenitors, but pulsars like PSR B1534+12 with its 2.7 Gyr coalescence time could produce such a merger. The displacement (similar to 2.2 kpc) of the binary star system from the centre of the main galaxy is not unusual for stars in the host galaxy or stars originating in the merging galaxy, and therefore any constraints on the kick velocity imparted to the progenitor are poor.
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- Ray, A. K., et al.
(författare)
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Damage resistance of a thermal barrier coated superalloy used in aero turbine blade under accelerated creep condition
- 2009
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Ingår i: High Temperature Materials and Processes. - 0334-6455 .- 2191-0324. ; 28:1-2, s. 35-53
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Tidskriftsartikel (refereegranskat)abstract
- This paper highlights the hot tensile and accelerated creep properties of a thermal barrier coated (TBC) AE 437A alloy used as a candidate blade material in aero engines. Acoustic emission technique has been utilised to characterise the ductile-brittle transition temperature of the bond coat. Results revealed that the DBTT (ductile to brittle transition temperature) of this bond coat is around 923 K, which is in close proximity to the value reported for NiCoCrAlY type of bond coat. Finite element technique used for analysing the equivalent stresses in the bond coat well within the elastic limit, revealed highest order of equivalent stress at 1073 K as the bond coat is ductile above 923 K. The lifetime of the TBC coated superai loy was superior to that of the bare substrate and that oxidation is likely the cause of the reduced life of the bare substrate as compared to the coated substrate while stress rupture or accelerated creep experiments are carried out in an oxidizing environment.. Delamination of the bond coat and that of the TBC at high stresses during accelerated creep was evident. During accelerated creep, the mode of fracture in the substrate at very high stresses was transgranular whereas that at low stresses was intergranular.
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- Balaji, G., et al.
(författare)
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Investigations on Hot-wall deposited Cadmium Sulphide buffer layer for thin film solar cell
- 2018
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Ingår i: Materials Letters. - : Elsevier BV. - 1873-4979 .- 0167-577X. ; 222, s. 82-87
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Tidskriftsartikel (refereegranskat)abstract
- Cadmium Sulphide (CdS) thin films were deposited on to well-cleaned soda lime glass substrates using hot wall deposition technique at room temperature. The structure of CdS thin films was found to be hexagonal with < 0 0 2 > orientation and after annealing the film crystallized to < 0 0 2 >, < 1 0 1 >, < 1 0 2 >, < 1 1 2 > directions. Raman Spectroscopy confirmed the hexagonal structure with a shift at 312 cm(1). SAED pattern from the Transmission electron microscopy also confirmed the formation of hexagonal CdS. X-ray Photoelectron Spectroscopy confirmed the formation of CdS with relevant at% of Cd and S. Field emission scanning electron microscopy images revealed smooth surface of the thin film with distinctive grains. Atomic force microscopy results showed a surface roughness of 4.47 nm. Transmission spectra of the films were studied and the transparency was found to be above 80%. The optical band gap was found to be around 2.4 eV in accordance with the reported values. The results show that device quality buffer layers can be deposited using Hot-wall deposition. (C) 2018 Elsevier B.V. All rights reserved.
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- Mondal, Debasish, et al.
(författare)
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Polycaprolactone-based biomaterials for tissue engineering and drug delivery: Current scenario and challenges
- 2016
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Ingår i: International Journal of Polymeric Materials. - : TAYLOR & FRANCIS AS. - 0091-4037 .- 1563-535X. ; 65:5, s. 255-265
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Tidskriftsartikel (refereegranskat)abstract
- Recently, poly (epsilon-caprolactone) (PCL) has gained a lot of attention, and shown great potential in biomedical applications. Among synthetic polymers, PCL is one of the easiest to process and manipulate into a large range of shapes and sizes due to its low melting temperature and its superior viscoelastic properties. In this review article the authors focus mainly on the properties of PCL-based biomaterials relevant to drug delivery and tissue engineering applications. The authors provide an insight into the recent developments and challenges of PCL-based biomaterials as a critical component of new therapeutic strategies for many diseases.
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