33,390 research outputs found
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Petrography and bulk composition of Miller Range 05035: a new lunar VLT gabbro
Miller Range (MIL) 05035 is a crystalline lunar mare gabbroic meteorite collected in Antarctica in 2005 [1]. It is an important new sample in the lunar meteorite (LM) collection as it is only one of ~8 to be classified as basaltic in nature. MIL 05035 is coarsely grained with large pyroxene grains ( 8mm) subophitically enclosing plagioclase grains ( 6mm), and accessory ilmenite, spinel, silica and sulphide phases
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Compositional analysis of the very-low-Ti mare basalt component of NWA 773 and comparison with low-Ti basalts, LAP03632 and LAP02436
Abstract not available
An ion probe study of the sulphur isotopic composition of Fe-Ni sulphides in CM carbonaceous chondrites
From the Introduction: The CM chondrites have endured variable degrees of aqueous alteration [1] which has changed their original mineralogy. A detailed study of the petrology and mineralogy of the sulphides in a suite of increasingly aqueously altered CMs, combined with sulphur isotope data measured in situ, can provide clues as to whether differences in the CM group are a result of different degrees of aqueous alteration, or whether they are the result of nebular heterogeneity
Modified sorting technique to mitigate the collateral mortality of trawled school prawns (Metapenaeus macleayi)
The potential for changes to onboard handling practices in order to improve the fate of juvenile school prawns (Metapenaeus macleayi) discarded during trawling were investigated in two Australian rivers (Clarence and Hunter) by comparing a purpose-built, water-filled sorting tray against a conventional dry tray across various conditions, including the range of typical delays before the start of sorting the catch (2 min vs. 15 min). Juvenile school prawns
(n= 5760), caught during 32 and 16 deployments in each river, were caged and sacrificed at four times: immediately
(T0), and at 24 (T24), 72 (T72), and 120 (T12 0) hours after having been discarded. In both rivers, most
mortalities occurred between T0 and T24 and, after adjusting for control deaths (<12%), were greatest for the
15-min conventional treatment (up to 41% at T120). Mixed-effects logistic models revealed that in addition to the sampling time, method of sorting, and delay in sorting, the weight of the catch, salinity, and percentage cloud cover were significant predictors of mortality. Although trawling
caused some mortalities and comparable stress (measured as L -lactate) in all school prawns, use of the water tray lessened the negative impacts of some of the above factors across both the 2-min and 15-min delays in sorting so that the overall discard mortality was reduced by more than a
third. When used in conjunction with selective trawls, widespread application of the water tray should help to
improve the sustainability of trawling for school prawns
Design mobile satellite system architecture as an integral part of the cellular access digital network
The Cellular Access Digital Network (CADN) is the access vehicle through which cellular technology is brought into the mainstream of the evolving integrated telecommunications network. Beyond the integrated end-to-end digital access and per call network services provisioning of the Integrated Services Digital Network (ISDN), the CADN engenders the added capability of mobility freedom via wireless access. One key element of the CADN network architecture is the standard user to network interface that is independent of RF transmission technology. Since the Mobile Satellite System (MSS) is envisioned to not only complement but also enhance the capabilities of the terrestrial cellular telecommunications network, compatibility and interoperability between terrestrial cellular and mobile satellite systems are vitally important to provide an integrated moving telecommunications network of the future. From a network standpoint, there exist very strong commonalities between the terrestrial cellular system and the mobile satellite system. Therefore, the MSS architecture should be designed as an integral part of the CADN. This paper describes the concept of the CADN, the functional architecture of the MSS, and the user-network interface signaling protocols
Time-resolved optical/near-IR polarimetry of V404 Cyg during its 2015 outburst
We present optical and near-IR linear polarimetry of V404 Cyg during its 2015
outburst and in quiescence. We obtained time resolved r'-band polarimetry when
the source was in outburst, near-IR polarimetry when the source was near
quiescence and multiple wave-band optical polarimetry later in quiescence. The
optical to near-IR linear polarization spectrum can be described by
interstellar dust and an intrinsic variable component. The intrinsic optical
polarization, detected during the rise of one of the brightest flares of the
outburst, is variable, peaking at 4.5 per cent and decaying to 3.5 per cent. We
present several arguments that favour a synchrotron jet origin to this variable
polarization, with the optical emission originating close to the jet base. The
polarization flare occurs during the initial rise of a major radio flare event
that peaks later, and is consistent with a classically evolving synchrotron
flare from an ejection event. We conclude that the optical polarization flare
represents a jet launching event; the birth of a major ejection. For this event
we measure a rather stable polarization position angle of -9 degrees E of N,
implying that the magnetic field near the base of the jet is approximately
perpendicular to the jet axis. This may be due to the compression of magnetic
field lines in shocks in the accelerated plasma, resulting in a partially
ordered transverse field that have now been seen during the 2015 outburst. We
also find that this ejection occurred at a similar stage in the repetitive
cycles of flares.Comment: 9 pages, 5 figures, accepted for publication by MNRA
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Optimal fibre architecture of soft-matrix ballistic laminates
This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.ijimpeng.2015.10.012Soft-matrix ballistic laminates (such as those composed of fibres of Ultra High Molecular-Weight Polyethylene, e.g. Dyneema® HB26 and Spectra Shield), find extensive use as catching type armour systems. The relationship between the lay-up of these laminates with respect to the observed failure mechanisms has not been empirically investigated in the open literature, and is the subject of this work. Lay-ups are characterised by two parameters: (i) sequencing (or interply lay-up angle) θ̅ and (ii) in-plane anisotropy β, and can be mapped on to θ̅–β space. Four geometries that lie at the extrema of this parameter space are designed, built and tested. Testing is through ball bearing impact on circular clamped plates. The anisotropy (β) is coupled to the macroscopic response of the plates, whilst sequencing (θ̅) is coupled to the microscopic response. Penetration velocity is strongly affected by pull-out at the boundary, and in the present study this is shown to account for two-thirds of the ballistic resistance. The results have implications for validation testing on scaled samples, predictive modelling and simulation, and armour design.The authors wish to thank DSM Dyneema for supplying material for the construction of laminate plates. Dyneema® is a trademark of DSM. Dr B. P. Russell was supported by a Ministry of Defence / Royal Academy of Engineering Research Fellowship. The authors are also appreciative of technical insight provided by Dr. O’Masta
On the Optical -- X-ray correlation from outburst to quiescence in Low Mass X-ray Binaries: the representative cases of V404 Cyg and Cen X-4
Low mass X-ray binaries (LMXBs) show evidence of a global correlation of
debated origin between X-ray and optical luminosity. We study for the first
time this correlation in two transient LMXBs, the black hole V404 Cyg and the
neutron star Cen X-4, over 6 orders of magnitude in X-ray luminosity, from
outburst to quiescence. After subtracting the contribution from the companion
star, the Cen X-4 data can be described by a single power law correlation of
the form , consistent with disk reprocessing. We
find a similar correlation slope for V404 Cyg in quiescence (0.46) and a
steeper one (0.56) in the outburst hard state of 1989. However, V404 Cyg is
about times optically brighter, at a given keV X-ray
luminosity, compared to Cen X-4. This ratio is a factor of 10 smaller in
quiescence, where the normalization of the V404 Cyg correlation also changes.
We show that once the bolometric X-ray emission is considered and the known
main differences between V404 Cyg and Cen X-4 are taken into account (a larger
compact object mass, accretion disk size, and the presence of a strong jet
contribution in the hard state for the black hole system) the two systems lie
on the same correlation. In V404 Cyg, the jet dominates spectrally at
optical-infrared frequencies during the hard state, but makes a negligible
contribution in quiescence, which may account for the change in its correlation
slope and normalization. These results provide a benchmark to compare with data
from the 2015 outburst of V404 Cyg and, potentially, other transient LMXBs as
well.Comment: Accepted on ApJ, 12 pages, 4 figures, 4 table
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