993 research outputs found
A Modeling of the Super-Eddington Luminosity in Nova Outbursts: V1974 Cygni
We have modeled nova light curves exceeding the Eddington luminosity. It has
been suggested that a porous structure develops in nova envelopes during the
super Eddington phase and the effective opacity is much reduced for such a
porous atmosphere. Based on this reduced opacity model, we have calculated
envelope structures and light curves of novae. The optically thick wind model
is used to simulate nova winds. We find that the photospheric luminosity and
the wind mass-loss rate increase inversely proportional to the reducing factor
of opacities, but the wind velocity hardly changes. We also reproduce the
optical light curve of V1974 Cygni (Nova Cygni 1992) in the super-Eddington
phase, which lasts 13 days from the optical peak 1.7 mag above the Eddington
luminosity.Comment: 8 pages, 4 figures, to appear in ApJ
The Cone Phase of Liquid Crystals: Triangular Lattice of Double-Tilt Cylinders
We predict the existence of a new defect-lattice phase near the nematic -
smectic-C (NC) transition. This tilt- analogue of the blue phase is a lattice
of double-tilt cylinders. We discuss the structure and stability of the cone
phase. We suggest that many `nematics' exhibiting short range layering and tilt
order may in fact be in the molten cone phase, which is a line liquid.Comment: 4 Pages, 3 Figure
Novel structural features of the ripple phase of phospholipids
We have calculated the electron density maps of the ripple phase of
dimyristoylphosphatidylcholine (DMPC) and palmitoyl-oleoyl phosphatidylcholine
(POPC) multibilayers at different temperatures and fixed relative humidity. Our
analysis establishes, for the first time, the existence of an average tilt of
the hydrocarbon chains of the lipid molecules along the direction of the ripple
wave vector, which we believe is responsible for the occurrence of asymmetric
ripples in these systems
Transcriptomic analysis of the poultry red mite, Dermanyssus gallinae, across all stages of the lifecycle
Acknowledgements Thanks go to the Centre for Genomic Research (CGR) at the University of Liverpool performing the TruSeq RNA-seq analysis and to our local layer farmers for their continued support and provision of mite material. Funding The authors gratefully acknowledge funding for this project from BBRSC (grant reference BB/J01513X/1), Zoetis and Akita Co. Ltd. and The British Egg Marketing Board Trust.Peer reviewedPublisher PD
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Instabilities in free-surface electroosmotic flows
This paper was presented at the 2nd Micro and Nano Flows Conference (MNF2009), which was held at Brunel University, West London, UK. The conference was organised by Brunel University and supported by the Institution of Mechanical Engineers, IPEM, the Italian Union of Thermofluid dynamics, the Process Intensification Network, HEXAG - the Heat Exchange Action Group and the Institute of Mathematics and its Applications.With the recent development of novel microfluidic devices electroosmotic flows with fluid/fluid interfaces have emerged as very important subjects of investigation. Two immiscible fluids may need to be
transported in a microchannel, or one side of a channel may be open to air for various purposes, including adsorption of airborne molecules to liquid for high-sensitivity substance detection. The liquid/liquid or
liquid/gas interface in these cases can deform, resulting in significant corrugations followed sometimes by incipient rupture of liquid layers. For electroosmotic flow the rupture, leading to shortcircuit, can cause overall failure of the device. It is thus imperative to know the conditions for the rupture as well as the initial interfacial instability. Studies based on the Debye-Huckle approximation reveal that all free-surface electroosmotic flows of thickness larger than the Debye screening length are unstable and selectively lead to
rupture. Layers of the order of Debye screening length, however, are not properly described by the Debye-Huckle approximation. Even for micro-scale layers, the rupture phenomenon can make local layer
thickness to be nanoscale. A fully coupled system of hydrodynamics, electric field, and ionic distribution need to be analyzed. In this paper linear instability and subsequent nonlinear developments of a nanoscale free-surface electroosmotic flow are reported.This study is sponsored by the Ministry of Education, Science and Technology of Korea through the World Class University Grant
Dynamic induced softening in frictional granular material investigated by DEM simulation
A granular system composed of frictional glass beads is simulated using the
Discrete Element Method. The inter-grain forces are based on the Hertz contact
law in the normal direction with frictional tangential force. The damping due
to collision is also accounted for. Systems are loaded at various stresses and
their quasi-static elastic moduli are characterized. Each system is subjected
to an extensive dynamic testing protocol by measuring the resonant response to
a broad range of AC drive amplitudes and frequencies via a set of diagnostic
strains. The system, linear at small AC drive amplitudes has resonance
frequencies that shift downward (i.e., modulus softening) with increased AC
drive amplitude. Detailed testing shows that the slipping contact ratio does
not contribute significantly to this dynamic modulus softening, but the
coordination number is strongly correlated to this reduction. This suggests
that the softening arises from the extended structural change via break and
remake of contacts during the rearrangement of bead positions driven by the AC
amplitude.Comment: acoustics, nonlinearity, granular medi
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