A rectangular gridded ion thruster discharge chamber is investigated for operation with multiple discharge cathode assemblies. The multiple-cathode approach attempts to increase thruster throughput and lifetime by operating three discharge cathode assemblies sequentially, possibly providing a threefold increase in discharge chamber life. Previous multiple-cathode electric propulsion devices, su...

The aim of this work is to present radar cross section (RCS) measurements of a panel constituted of a flat aluminum plate with and without radar absorbing materials (RAM) type thin rubber sheets, in the range of 8 – 12 GHz. Two different loads were evaluated in the RAM formulation: 1. Magnetic (ferrites MnZn, NiZn and MgZn based), and 2. Dielectric (conducting polymers polyaniline based). The m...

BACKGROUND The purpose of this study was to determine the rate and causes of inappropriate rhythm detection, and to compare adequacy of ventricular arrhythmia detection by single-chamber and dual-chamber cardioverter-defibrillators (ICD). METHODS We evaluated 190 patients (age 57.2 +/- 11.2 years) with ICD. FOLLOW-UP 34.3 +/- +/- 22 months. Dual-chamber ICD was used in 54 patients. RESULT...

* Presented as Paper IEPC-03-0069 at the 28 International Electric Propulsion Conference, Toulouse, France, March 17 – 21, 2003. Published by the Electric Rocket Propulsion Society with permission. † Graduate Student, Aerospace Engineering, [email protected]. ‡ Graduate Student, Aerospace Engineering. § Associate Professor and Laboratory Director. A method for delivering a symmetric double ...

Lava dome eruptions commonly display fairly regular alternations between periods of high activity and periods of low or no activity. The time scale for these alternations is typically months to several years. Here we develop a generic model of magma discharge through a conduit from an open-system magma chamber with continuous replenishment. The model takes account of the principal controls on f...

The behavior of a hollow cathode operated within an ion thruster discharge chamber is characterized using a remotely located, charged-particle analyzer. A very complex structure of the ion energy distribution function is revealed that is in general agreement with previous observations from many earlier works. Observations, which are in general agreement with the literature, include the measurem...

BACKGROUND Patients in acute hospital care show a high risk for venous thromboembolism (VTE); 52% of patients globally are at risk, with approximately only half receiving appropriate prophylaxis. OBJECTIVES The TUNE-IN study's primary objective was to evaluate the use of VTE prophylaxis in the private sector in South Africa in hospitalised patients in relation to patient risk profile, via bot...

Electron energy distribution functions (EEDF’s) are presented over a two-dimensional array of locations in the discharge chamber of a 40-cm diameter ring-cusp ion thruster. The EEDF’s are obtained using two different techniques illustrating comparable results. A distinct difference in the EEDF’s measured through the double layer potential gradient, which transitions between the low-potential di...

Various electrodynamic models of a combustion chamber with an initiated subcritical streamer discharge used to ignite combustible air/fuel mixture are considered. To localize the in working chamber, initiators based on half-wave electromagnetic vibrators resonant properties applied. The dependencies structure electric field forming geometric parameters initiator obtained, and integration genera...