Large transverse wake fields can be generated via the interaction between a relativistic electron or positron bunch and a plasma, and the bunch will therefore be self-pinched. In this paper we derive a new and general formulation for the plasma wake field in a compact expression. We then suggest that this self-focusing effect can be used as a mechanism to enhance the luminosity for high energy ...

emergence of primary signs of muslims uprising in tunisia, egypt, libya, bahrain, yemen, and, in a somehow limited form, in arabia and jordan against local tyranny and foreign colonization, made big powers and western expansionist countries to expropriate public movements to their own benefit and to deviate such movements from their true path. in fact, the matter of process or project nature of...

in this study, changes in speed and turbulence intensity in the wake of a peugeot model and the drag coefficient changes with increases vehicle speed in unsteady flow measured and evaluated. the blow open circuit wind tunnel to simulate fluid flow is used. disturbances and nominal maximum speed of the device, respectively is, 30 m / s and 0.01%. has been continuously increasing speed by an inve...

Water stratified thermally or with dissolved material has a refractive index that varies with height. The stratification has no obvious visual effect until the fluid is disturbed, for example by a fish, but then it marks the creature's wake with a jump in refractive index that is visible in shadowgraphic projection. Two shadowgraphs in stereo display the wake in three dimensions. For a permanen...

This paper presents measurements and model predictions of the density and size distribution of bubbles in the wakes of full scale ships, and the effects of the bubbles on acoustic propagation. The ship wake is primarily a hydrodynamic process, characterized by temporally and spatially varying flow conditions (i.e., local fluid velocity, pressure, turbulent kinetic energy and dissipation, etc.) ...

Direct numerical simulation is used to simulate the turbulent wake behind an accelerating axisymmetric self-propelled body in a stratified fluid. Acceleration is modelled by adding a velocity profile corresponding to net thrust to a self-propelled velocity profile resulting in a wake with excess momentum. The effect of a small to moderate amount of excess momentum on the initially momentumless ...

RATIONALE Long-term intermittent hypoxia (LTIH) exposure in adult mice, modeling oxygenation patterns of moderate-severe obstructive sleep apnea, results in lasting hypersomnolence and is associated with nitration and oxidation injuries in many brain regions, including wake-active regions. OBJECTIVES We sought to determine if LTIH activates inducible nitric oxide synthase (iNOS) in sleep/wake...

Disruption of sleep is a frequent complaint among elderly humans and is also evident in aged laboratory rodents. The neurobiological bases of age-related sleep/wake disruption are unknown. Given the critical role of the hypocretins in sleep/wake regulation, we sought to determine whether the wake-promoting effect of hypocretin changes with age in Wistar rats, a strain in which age-related chang...

The effect of base suction on a plane wake was found to produce significant changes on wake dynamics. The wake is produced by merging two boundary layers from the trailing edge of a splitter plate in a two stream water tunnel. A threshold suction speed exists which is equal to half of the free stream velocity. If the suction speed is below the threshold, the wake flow is unstable. If the suctio...