Synchronised flame dynamics

Synchronised flame dynamic

Arrays of coupled chemical oscillators

Oscillating chemical reactions result from complex periodic changes in the concentration of the reactants. In spatially ordered ensembles of candle flame oscillators the fluctuations in the ratio of oxygen atoms with respect to that of carbon, hydrogen and nitrogen produces an oscillation in the visible part of the flame related to the energy released per unit mass of oxygen. Thus, the products of the reaction vary in concentration as a function of time, giving rise to an oscillation in the amount of soot and radiative emission. Synchronisation of interacting dynamical sub-systems occurs as arrays of flames that act as master and slave oscillators, with groups of candles numbering greater than two, creating a synchronised motion in three-dimensions. In a ring of candles the visible parts of each flame move together, up and down and back and forth, in a manner that appears like a “worship”. Here this effect is shown for rings of flames which collectively empower a central flame to pulse to greater heights. In contrast, situations where the central flames are suppressed are also found. The phenomena leads to in-phase synchronised states emerging between periods of anti-phase synchronisation for arrays with different columnar sizes of candle and positioning

A cancers addiction to glutamine affects the whole body and could lead to complex skin rashes

A cancers addiction to glutamine affects the whole body and could lead to complex skin rashe

Self-assembled multi-ring formations of glutamine and a possible link to erythema gyratum repens

In the body l-glutamine is abundant and required for the proliferation of cells. Indeed human physiology is dependent upon having and maintaining the correct glutamine levels for a range of functions including neurological signalling and a healthy immune system. However, during tumourigenesis cell proliferation demands elevated levels of glutamine, which can ultimately lead to muscle atrophy. In some cases the skin provides the first indications of the underlying disease and erupts in a wave of complicated pattern formations. One such skin marker is erythema gyratum repens. We investigated the pattern formations associated with concentrations of glutamine in aqueous solutions at levels higher than that of a normal biological functionality. We find remarkable similarities between the patterns of erythema gyratum repens and the unusual self-assembled patterns of glutamine. The findings may lead to new therapeutics and understanding for those working in oncology and toxicology. Utilising the formations associated with glutamine could also assist in bio-functionalising micro and nanoparticles for high efficacy

Rapid reproduction of complex images in graphite by laser etching and exfoliation

We describe a means to produce thin layers of carbon, graphene multilayers, using laser etching followed by exfoliation. Complex macroscopic images can be produced in minutes. The laser need only mark the top-most layers of graphene for the image to become permanent down to the glass substrate. We use the technique to produce artwork for proof of principle results. With refinement the methodology should also enable patterning of novel graphene electronic and optoelectronic devices

Whispering galleries and the control of artificial atoms

Quantum computation using artificial-atoms, such as novel superconducting circuits, can be sensitively controlled by external electromagnetic fields. These fields and the self-fields attributable to the coupled artificial-atoms influence the amount of quantum correlation in the system. However, control elements that can operate without complete destruction of the entanglement of the quantum-bits are difficult to engineer. Here we investigate the possibility of using closely-spaced-linear arrays of metallic-elliptical discs as whispering gallery waveguides to control artificial-atoms. The discs confine and guide radiation through the array with small notches etched into their sides that act as scatterers. We focus on Ï €-ring artificial-atoms, which can generate their own spontaneous fluxes. We find that the micro-discs of the waveguides can be excited by terahertz frequency fields to exhibit whispering-modes and that a quantum-phase-gate composed of Ï €-rings can be operated under their influence. Furthermore, we gauge the level of entanglement through the concurrence measure and show that under certain magnetic conditions a series of entanglement sudden-deaths and revivals occur between the two qubits. This is important for understanding the stability and life-time of qubit operations using, for example, a phase gate in a hybrid of quantum technologies composed of control elements and artificial-atoms

Rapid reproduction of complex images in graphite by laser etching and exfoliation

We describe a means to produce thin layers of carbon, graphene multilayers, using laser etching followed by exfoliation. Complex macroscopic images can be produced in minutes. The laser need only mark the top-most layers of graphene for the image to become permanent down to the glass substrate. We use the technique to produce artwork for proof of principle results. With refinement the methodology should also enable patterning of novel graphene electronic and optoelectronic devices

Ultrasound propagation in concentrated random dispersions of spherical particles: thermal- and shear-mediated contributions to multiple scattering

Ultrasound propagation in concentrated random dispersions of spherical particles: thermal- and shear-mediated contributions to multiple scatterin

Graphene levitons and anti-levitons in magnetic fields

The leviton is an electron or hole wavepacket that rides the surface of the Fermi sea. When a series of Lorentzian or Gaussian time dependent pulses are applied to an ultracold system a soliton-like excitation with only one electron and no localised hole emerges. Graphene is a unique system where the Fermi surface may arise from a Dirac point and therewith the levitons character may display many interesting features. For example, the leviton formation may be associated with a chiral anomaly, and inside a single potential step an anti-leviton forms. We show that the application of weak magnetic fields may switch on and off the leviton Klein tunnelling. Also, in a moderate field negative refraction arises along a curved trajectory, whereas with a stronger field a new elementary excitation – the levity vortex – in the reflected wavefunction occurs. Herein we describe these phenomena in detail along with a complete explanation of the transmission of graphene levitons at a step potential in terms of the probability densities and a series of phase diagrams and the tunnelling times

Multiple scattering in random dispersions of spherical scatterers: effects of shear-acoustic interactions

The propagation of acoustic waves through a suspension of spherical particles in a viscous liquid is investigated, through application of a multiple scattering model. The model is based on the multiple scattering formulation of Luppé, Conoir and Norris (J. Acoust. Soc. Am. 2012, 131, 1113) which incorporated the effects of thermal and shear wave modes on propagation of the acoustic wave mode. Here, the model is simplified for the case of solid particles in a liquid, in which shear waves make a significant contribution to the effective properties. The relevant scattering coefficients and effective wavenumber are derived in analytical form. The results of calculations are presented for a system of silica particles in water, illustrating the dependence of the scattering coefficients, effective wavenumber, speed, attenuation on particle size and frequency. The results demonstrate what has already been shown experimentally; that the shear-mediated processes have a very significant effect on the effective attenuation of acoustic waves, especially as the concentration of particles increases