Evaluation of a dual-mode, turbojet-turboprop engine for unmanned aircraft

This paper provides experimental feedback on the feasibility of a small-scale, dual-mode turbojet to turboprop engine. The engine used for testing was a KingTech K45-TP. Key parameters focused on for this experiment were turbojet and turboprop thrust. A parametric cycle analysis was performed on a pure turbojet configuration and turboprop configuration, then using mass flow parameter various nozzles were sized to be designed and tested. Mission analysis was also performed to get an idea of the required thrust that could be expected for takeoff and flight. The experiment examines the effect of turbojet thrust with respect to varying nozzle exit diameters, as well as nozzle location relative to the exhaust exit. The engine was run in both turbojet mode and turboprop mode with the various nozzle designs with exit diameters measuring from roughly 1.5 inches to 1 inch. During each test, the nozzles started at a backoff distance of two inches and as the engine was running the nozzles were moved forward at quarter inch increments until the backoff distance was half an inch. While running the engine in turbojet mode, there was a highlighted focus on a potential performance increase in turbojet thrust as the nozzles were moved closer to the exhaust. While running the engine in turboprop mode, the highlighted focus was if there was a performance decrease in turboprop thrust as the nozzles were moved closer to the exhaust. Results show that there is an optimal nozzle geometry and placement for turbojet mode, with little effect while running in turboprop mode. Overall, the turbojet thrust recorded during testing is found to be inadequate for high-speed cruise, however the thrust that is produced could be useful for a transition to turboprop mode from a RATO takeoff with a propeller lock

TRIGA-SPEC: A setup for mass spectrometry and laser spectroscopy at the research reactor TRIGA Mainz

The research reactor TRIGA Mainz is an ideal facility to provide neutron-rich nuclides with production rates sufficiently large for mass spectrometric and laser spectroscopic studies. Within the TRIGA-SPEC project, a Penning trap as well as a beam line for collinear laser spectroscopy are being installed. Several new developments will ensure high sensitivity of the trap setup enabling mass measurements even on a single ion. Besides neutron-rich fission products produced in the reactor, also heavy nuclides such as 235-U or 252-Cf can be investigated for the first time with an off-line ion source. The data provided by the mass measurements will be of interest for astrophysical calculations on the rapid neutron-capture process as well as for tests of mass models in the heavy-mass region. The laser spectroscopic measurements will yield model-independent information on nuclear ground-state properties such as nuclear moments and charge radii of neutron-rich nuclei of refractory elements far from stability. This publication describes the experimental setup as well as its present status.Comment: 20 pages, 17 figure

Calibration of the ISOLDE acceleration voltage using a high-precision voltage divider and applying collinear fast beam laser spectroscopy

A high-voltage divider with accuracy at the ppm level and collinear laser spectroscopy were used to calibrate the highvoltage installation at the radioactive ion beam facility ISOLDE at CERN. The accurate knowledge of this voltage is particularly important for collinear laser spectroscopy measurements. Beam velocity measurements using frequencycomb based collinear laser spectroscopy agree with the new calibration. Applying this, one obtains consistent results for isotope shifts of stable magnesium isotopes measured using collinear spectroscopy and laser spectroscopy on laser-cooled ions in a trap. The long-term stability and the transient behavior during recovery from a voltage dropout were investigated for the different power supplies currently applied at ISOLDE.Comment: 13 pages, 6 figure

Die teileingezahlte Namensaktie als Finanzierungsinstrument der Versicherungswirtschaft

Einführung der Stückaktie • Recht der Europäischen Gemeinschaft • teil- und volleingezahlte Aktien • Umstellung der Aktie auf Eur

L'action pédagogique : une introduction aux professions de la pédagogie sociale /

Bibliogr.: p. 384-393