BACKGROUND Superimposed high-frequency jet ventilation (SHFJV), which does not require any tracheal tubes or catheters, was developed specifically for use in laryngotracheal surgery. SHFJV uses two jet streams with different frequencies simultaneously and is applied in the supraglottic space using a jet laryngoscope and jet ventilator. METHODS Between 1990 and 2004, SHFJV was studied in 1515 ...

One possible method of reducing jet noise at takeoff is the use of an ejector in which the propelling nozzle discharges into a shroud and thereby induces a secondary flow. The present report describes an experiment on the aerodynamics of such systems. The primary nozzle was axisymmetric and convergent and the shrouds were cylindrical with faired convergent entries. The stagnation temperatures o...

OBJECTIVE To describe our experience with superimposed high-frequency jet ventilation (SHFJV), which does not require any endotracheal tubes or catheters, for performing laryngeal and tracheal surgery. DESIGN A case series of 500 patients. SETTING A university medical center. PATIENTS Four hundred sixty adult patients and 40 children in a consecutive sample who required laryngeal or trach...

The simulation of plane impinging jets using the Lagrangian technique of smooth particle hydrodynamics is presented. In Section 1 the impingement of a plane jet onto a stationary surface is considered for Reynolds numbers 800, 4000, 8000 and Froude number 4. For each case, the height of the associated streams is measured and compared with both experimental and theoretical results. The agreement...

Jet-refrigeration cycles seem to provide an interesting solution to the increasing interest in environment protection and the need for energy saving due to their low plant costs, reliability and possibility to use water as operating fluid. A steam/steam ejector cycle refrigerator is investigated introducing a two-stage ejector with annular primary at the second stage. The steady_state refrigera...

In the present paper the characterization of the flow field generated by means of a submerged gaseous jet exited by means of a coaxial synthetic jet has been investigated. The purpose of this investigation is to infer the aerodynamic interaction of the two fluid structures that play an interesting role in several industrial applications like jet actuator, flame stability in the combustor for mi...

Relativistic jets carry a significant fraction of the total energy budget of a radio source, rivaling the power that is extracted through accretion. A minor part of this bulk kinetic power is transformed to radiation, possibly through internal shocks if the plasma is accelerated, at the base of the jet, to a velocity which changes in time. In this way we can understand why some radiation is pro...

We present here new observations conducted with the EVN and MERLIN of the persistent microquasar LS 5039 discovered by Paredes et al. (2000) with the VLBA. The new observations confirm the presence of an asymmetric two-sided jet reaching up to ∼ 1000 AU on the longest jet arm. The results suggest a bending of the jets with increasing distance from the core and/or precession. The origin and loca...

An experimental study of simultaneous multi-point measurements in the flow and acoustic fields of a Mach 1.75 cold air jet is presented. A series of four optical deflectometer (OD) probes were used for the flow field measurements, and eight microphones arranged on a circular arc recorded the far-field pressure in the direction of peak emission. In addition, some of the OD probes were positioned...

As part of DARPA's MARS2020 program, the Jet Propulsion Laboratory developed a vision-based system for localization in urban environments that requires neither GPS nor active sensors. System hardware consists of a pair of small FireWire cameras and a standard Pentium-based computer. The inputs to the software system consist of: 1) a crude grid-based map describing the positions of buildings, 2 ...