McGaughey D.R.,Royal Military College of Canada |
MTS/IEEE Seattle, OCEANS 2010 | Year: 2010
Sound from a torpedo will be received by an underwater hydrophone along multiple paths. Due to different arrival angles, the signals from the multiple paths will be Doppler shifted relative to each other. By separating the multi-path signals an estimate of the range can be found using trigonometric relationships. A high spectral resolution estimator called the fast orthogonal search (FOS) is used to estimate tones from the torpedo whose frequency spacing is much less than the fast Fourier transform resolution limit. An adaptive candidate FOS algorithm (AFOS) was developed to detect two tones with closely frequencies and short record lengths. The torpedo detection algorithm used record lengths of 10 s and estimated the range of the approaching torpedo to within 4.2 m for initial angles of approach ranging from 0° to 20°. and ranges less than 3000 m. ©2010 Crown.
Mazzitelli G.,ENEA |
Apicella M.L.,ENEA |
Fusion Engineering and Design | Year: 2011
The choice of the best material exposed to the plasma in a future reactor is still an open question. One of main requirements to be satisfied is the capability to withstand high heat loads, in the range 10-20 MW/m2, during normal operations in a future reactor, as well as the peak power released by ELMs in H-mode operation. On FTU, since the end of 2005, we have started an innovative program having as main goal the possibility to expose a liquid surface to the plasma. The small wetted area, of the FTU three liquid lithium limiter units, does not allow to use it as main limiter for all the duration of the discharge so that it is always set in the shadow of the main toroidal limiter. In this condition, heat loads up to 2 MW/m2 are normally withstood by the liquid lithium limiter without any surface damage and problems to the FTU operations. In order to increase the heat load on the liquid lithium limiter for a controlled limited period, the plasma column is shifted towards the liquid lithium limiter during the discharge. The surface temperature remains constant although the plasma column is pushed on the liquid lithium limiter. This saturation of the surface temperature can be understood considering the dependence of the evaporation rate versus the surface temperature between 250 °C and 550 °C that increases by five orders of magnitude. The evaporated lithium forms a strongly radiative cloud all around the three units limiting the power load on the surface. We do not observe any accumulation of lithium into the discharge as it can be also inferred from the time evolution of the Li III line growing up until the temperature is reaching the maximum value and then remaining almost constant. © 2011 EURATOM. Published by Elsevier B.V. All rights reserved.
Trinity | Date: 2010-03-15