Experimental and theoretical investigations of the infrared-active, polarization-dependent phonon frequencies of cubic boron nitride films have been performed in light of recent claims that large frequency shifts during initial nucleation are the result of strain caused by highly nonequilibrium growth conditions. We show that the formation of small, separate grains of cubic boron nitride during...

In the present work we present a systematic experimental investigation of the generation and subsequent evolution of dynamic failure modes in sandwich structures subjected to low-speed impact. Model sandwich specimens involving a compliant polymer core sandwiched between two metal layers were designed and subjected to impact loading to simulate failure evolution mechanisms in real sandwich stru...

A two-field model for collisionless trapped electron mode turbulence has both finite amplitude-induced stability and instability, depending on wave number. Effects usually identified with nonlinear plasma instability ~self-trapping, kinetics, 3D mode structure, magnetic shear! are absent. Nonlinear stability and instability reside in E3B advection of density. It drives modes of a purely damped ...

Strange modes have been found in the radial spectrum of many luminous stars, such as PAGB stars. The strange modes are characterized by having small amplitudes in the interior of the envelope, and egregious periods and growth-rates. It has been common belief that the strange modes are a result of strong nonadiabaticity. Recently, and perhaps surprisingly, such modes have also been found in clas...

A simplified model problem is used to illustrate some of the parameters controlling the radiation of sound into an ambient medium due to the growth and subsequent decay of subsonic travelling waves, such as may occur via non-linear interactions in turbulent free shear flows. It is shown that substantial sound may be generated by apparently subsonic modes as a result of their growth and decay ch...

The hollow plasma channel is analyzed as an accelerating structure. The excitation of the channel by an ultrarelativistic beam is analyzed. Coupling to the fundamental and all higher-order azimuthal modes of the excited electromagnetic fields is derived. Implications of this work for plasma-based accelerators, including beam loading and beam breakup, are discussed. Small initial transverse disp...

Delamination is a critical form of failure in composite laminates which is partitioned into a combination of three pure modes namely; opening, shearing and tearing (modes I, II and III respectively). Each fracture mode contributes to the total energy required for delamination growth, due to a combination of the different damage mechanisms that occur under each mode 1-2 . To formulate reliable m...

The noisy Burgers equation describing for example the growth of an interface subject to noise is one of the simplest model governing an intrinsically nonequilibrium problem. In one dimension this equation is analyzed by means of the MartinSiggia-Rose technique. In a canonical formulation the morphology and scaling behavior are accessed by a principle of least action in the weak noise limit. The...

We investigate L7 photonic crystal microcavities (PCMs) fabricated by epitaxial re-growth of GaAs pre-patterned substrates, containing InAs quantum dots. The resulting PCMs show hexagonal shaped nano-holes due to the development of preferential crystallographic facets during the re-growth step. Through a careful control of the fabrication processes, we demonstrate that the photonic modes are pr...

Big data and data-driven innovation are drivers for economic growth. To capture this growth, data often need to be shared among organisations. However, many challenges to sharing data among organisations exist. This paper investigates how governance is organised in inter-organisational data collaborations. First, based on literature, four archetypical modes of governance are identified: Market,...