110 research outputs found
Propagation of Detonation Waves in Tubes Split from a PDE Thrust Tube
A Pulse Detonation Engine (PDE) combusts a fuel air mixture through detonation. Existing designs require spark plugs in each separate thrust tube to ignite premixed reactants. A single thrust tube could require the spark plug to fire hundreds of times per second for long durations. This paper reports on the use of a continuously propagating detonation wave as both a thrust producer and a single ignition source for a multi-tube system. The goal was to minimize ignition complexity and increase reliability by limiting the number of ignition sources. The work includes a systematic investigation of single tube geometric effects on detonations. These results were subsequently used to further examine conditions for splitting detonations i.e. the division of a detonation wave into two separate detonation waves. Finally a dual thrust tube system was built and tested that successfully employed a single spark to initiate detonation in separate thrust tubes
Fermion Representation Of The Rolling Tachyon Boundary Conformal Field Theory
A free fermion representation of the rolling tachyon boundary conformal field
theory is constructed. The representation is used to obtain an explicit,
compact, exact expression for the boundary state. We use the boundary state to
compute the disc and cylinder amplitudes for the half-S-brane.Comment: 27 page
Linear Predictability vs. Bull and Bear Market Models in Strategic Asset Allocation Decisions: Evidence from UK Data
Rayleigh Imaging of Graphene and Graphene Layers
We investigate graphene and graphene layers on different substrates by
monochromatic and white-light confocal Rayleigh scattering microscopy. The
image contrast depends sensitively on the dielectric properties of the sample
as well as the substrate geometry and can be described quantitatively using the
complex refractive index of bulk graphite. For few layers (<6) the
monochromatic contrast increases linearly with thickness: the samples behave as
a superposition of single sheets which act as independent two dimensional
electron gases. Thus, Rayleigh imaging is a general, simple and quick tool to
identify graphene layers, that is readily combined with Raman scattering, which
provides structural identification.Comment: 8 pages, 9 figure
First outbreaks and phylogenetic analyses of avian influenza H9N2 viruses isolated from poultry flocks in Morocco
Delayed anemia assessment in patients treated with oral artemisinin derivatives for uncomplicated malaria: a pooled analysis of clinical trials data from Mali
Clinical overview and treatment options for non-skeletal manifestations of mucopolysaccharidosis type IVA
Severe falciparum malaria complicated by prolonged haemolysis and rhinomaxillary mucormycosis after parasite clearance: a case report
Clinical illness and outcomes in Nigerian children with late-appearing anaemia after artemisinin-based combination treatments of uncomplicated falciparum malaria
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