Channel-based antenna synthesis for improved in-vehicle UWB MB-OFDM communications

Ultra-wide band (UWB) is an attractive technology for innovative in-vehicle wireless communications requiring high data rates and multiband orthogonal frequency division multiplexing (MB-OFDM) a suitable scheme for the accomplishment due to its high performance, low-power and low-cost characteristics. To contribute toward improved UWB MB-OFDM communications inside vehicles, a channel-based antenna synthesis technique to customise in-vehicle UWB antennas that reduce ‘blind spots’ in the communication channel is proposed and presented. For the realisation, a comprehensive analysis was utilised and comprised an in-car channel evaluation including bit-error-rate (BER) estimations and radiation pattern-and-source syntheses. The channel was measured using a standard antenna to set up the base of the experiments and the distribution of the impulse responses and signal-to-noise ratios in the vehicle's passenger plane shown. The currently available IEEE 802.15.3a channel models were perceived unrealistic for the in-vehicle application and the reason for measuring the channel practically. Using these specific channel measurements, the synthesised pattern is unveiled and consequently the channel-based antenna synthesis technique used to predict the antenna source. The antenna with optimised pattern-and-source showed an improved BER performance compared with the standard antenna in this application; that is, a figure of merit of 37.73% minimised ‘blind spots’

Vortices in magnetically coupled superconducting layered systems

Pancake vortices in stacks of thin superconducting films or layers are considered. It is stressed that in the absence of Josephson coupling topological restrictions upon possible configurations of vortices are removed and various examples of structures forbidden in bulk superconductors are given. In particular, it is shown that vortices may skip surface layers in samples of less than a certain size R_c which might be macroscopic. The Josephson coupling suppresses R_c estimates

Decoherence and entanglement degradation of a qubit-qutrit system in non-inertial frames

We study the effect of decoherence on a qubit-qutrit system under the influence of global, local and multilocal decoherence in non-inertial frames. We show that the entanglement sudden death can be avoided in non-inertial frames in the presence of amplitude damping, depolarizing and phase damping channels. However, degradation of entanglement is seen due to Unruh effect. It is shown that for lower level of decoherence, the depolarizing channel degrades the entanglement more heavily as compared to the amplitude damping and phase damping channels. However, for higher values of decoherence parameters, amplitude damping channel heavily degrades the entanglement of the hybrid system. Further more, no ESD is seen for any value of Rob's acceleration.Comment: 16 pages, 5 .eps figures, 1 table; Quantum Information Processing, published online, 5 July, 201

SU(3) symmetry breaking in lower fp-shell nuclei

Results of shell-model calculations for lower fp-shell nuclei show that SU(3) symmetry breaking in this region is driven by the single-particle spin-orbit splitting. However, even though states of the yrast band exhibit SU(3) symmetry breaking, the results also show that the yrast band B(E2) values are insensitive to this fragmentation of the SU(3) symmetry; specifically, the quadrupole collectivity as measured by B(E2) transition strengths between low lying members of the yrast band remain high even though SU(3) appears to be broken. Results for $^{44,46,48}Ti$ and $^{48}Cr$ using the Kuo-Brown-3 two-body interaction are given to illustrate these observations.Comment: Updated to the published versio

Porcine colonization of the Americas: a 60k SNP story.

Made available in DSpace on 2018-07-01T01:24:17Z (GMT). No. of bitstreams: 1 hdy2012109a.pdf: 1129860 bytes, checksum: 44683cde430ba3f771242018513366b0 (MD5) Previous issue date: 2013-02-26bitstream/item/179305/1/hdy2012109a.pd

The Stellar Content and Star Formation History of the late-type spiral galaxy NGC 300 from Hubble Space Telescope observations

We present the first WFPC2 V, I photometry for the Sculptor Group galaxy NGC 300 in four fields ranging from the centre to the outer edge. We have made the first measurement of the star formation histories in two disk fields: the oldest stars were born at similar epochs and formation activity increased but at different mean rates. The main disk stellar population is predominantly old, consisting of RGB and AGB stars, based on a synthetic colour magnitude diagram analysis. Z is found to have been more metal poor than 0.006 (or 0.33Zsolar) with no evidence for significant change in the mean Z value over time in both disk fields. In the central region, we find a dearth of bright stars with respect to the two disk fields that cannot be explained by observational effects. Taken at face value, this finding would agree with the Davidge (1998) report of suppressed star formation there during the past 1Gyr with respect to his disk fields at larger radii; but the possibility of significant central extinction affecting our finding remains. We have also determined the first distance modulus estimate based on the tip of the red giant branch method: on the Cepheid distance scale of Ferrarese et al. (2000) we find (m-M)o = 26.56+/-0.07 (+/-0.13) mag; and a similar value from the Cepheid-independent empirical method by Lee et al. (1993), both in good agreement with the Cepheid distance determined by Freedman et al. (2001). A discrepancy between this and the theoretical calibration of the red giant branch tip magnitude method remains. Finally, we report a newly detected young (up to about 10Myr) stellar association of about average size (~140pc) in one of the disk fields.Comment: 47 pages, 12 figures (the quality of Figures 1 and 6 has been degraded), Corrected minor textual errors and two reference omissions to match the version to be published in The Astronomical Journa

The non-conservation of potential vorticity by a dynamical core compared with the effects of parametrized physical processes

Numerical models of the atmosphere combine a dynamical core, which approximates solutions to the adiabatic, frictionless governing equations for fluid dynamics, with tendencies arising from the parametrization of other physical processes. Since potential vorticity (PV) is conserved following fluid flow in adiabatic, frictionless circumstances, it is possible to isolate the effects of non-conservative processes by accumulating PV changes in an air-mass relative framework. This “PV tracer technique” is used to accumulate separately the effects on PV of each of the different non-conservative processes represented in a numerical model of the atmosphere. Dynamical cores are not exactly conservative because they introduce, explicitly or implicitly, some level of dissipation and adjustment of prognostic model variables which acts to modify PV. Here, the PV tracers technique is extended to diagnose the cumulative effect of the non-conservation of PV by a dynamical core and its characteristics relative to the PV modification by parametrized physical processes. Quantification using the Met Office Unified Model reveals that the magnitude of the non-conservation of PV by the dynamical core is comparable to those from physical processes. Moreover, the residual of the PV budget, when tracing the effects of the dynamical core and physical processes, is at least an order of magnitude smaller than the PV tracers associated with the most active physical processes. The implication of this work is that the non-conservation of PV by a dynamical core can be assessed in case studies with a full suite of physics parametrizations and directly compared with the PV modification by parametrized physical processes. The nonconservation of PV by the dynamical core is shown to move the position of the extratropical tropopause while the parametrized physical processes have a lesser effect at the tropopause level

Cross section measurements of 155,157Gd(n, γ) induced by thermal and epithermal neutrons

© SIF, Springer-Verlag GmbH Germany, part of Springer Nature 2019Neutron capture cross section measurements on 155Gd and 157Gd were performed using the time-of-flight technique at the n_TOF facility at CERN on isotopically enriched samples. The measurements were carried out in the n_TOF experimental area EAR1, at 185 m from the neutron source, with an array of 4 C6D6 liquid scintillation detectors. At a neutron kinetic energy of 0.0253 eV, capture cross sections of 62.2(2.2) and 239.8(8.4) kilobarn have been derived for 155Gd and 157Gd, respectively, with up to 6% deviation relative to values presently reported in nuclear data libraries, but consistent with those values within 1.6 standard deviations. A resonance shape analysis has been performed in the resolved resonance region up to 181 eV and 307 eV, respectively for 155Gd and 157Gd, where on average, resonance parameters have been found in good agreement with evaluations. Above these energies and up to 1 keV, the observed resonance-like structure of the cross section has been analysed and characterised. From a statistical analysis of the observed neutron resonances we deduced: neutron strength function of 2. 01 (28) × 10 - 4 and 2. 17 (41) × 10 - 4; average total radiative width of 106.8(14) meV and 101.1(20) meV and s-wave resonance spacing 1.6(2) eV and 4.8(5) eV for n + 155Gd and n + 157Gd systems, respectively.Peer reviewedFinal Accepted Versio

Survey of advanced nuclear technologies for potential applications of sonoprocessing

Ultrasonics has been used in many industrial applications for both sensing at low power and processing at higher power. Generally, the high power applications fall within the categories of liquid stream degassing, impurity separation, and sonochemical enhancement of chemical processes. Examples of such industrial applications include metal production, food processing, chemical production, and pharmaceutical production. There are many nuclear process streams that have similar physical and chemical processes to those applications listed above. These nuclear processes could potentially benefit from the use of high-power ultrasonics. There are also potential benefits to applying these techniques in advanced nuclear fuel cycle processes, and these benefits have not been fully investigated. Currently the dominant use of ultrasonic technology in the nuclear industry has been using low power ultrasonics for non-destructive testing/evaluation (NDT/NDE), where it is primarily used for inspections and for characterizing material degradation. Because there has been very little consideration given to how sonoprocessing can potentially improve efficiency and add value to important process streams throughout the nuclear fuel cycle, there are numerous opportunities for improvement in current and future nuclear technologies. In this paper, the relevant fundamental theory underlying sonoprocessing is highlighted, and some potential applications to advanced nuclear technologies throughout the nuclear fuel cycle are discussed