An acoustic study of pulsation characteristics of fires
The pulsation characteristic of fires was examined using acoustic parameters at very low sonic and subsonic frequencies up to 2 Hz. The existences of a characteristic frequency related to the diameter of the seat of the fire was demonstrated. The signal was found to decay rapidly with distance, suggesting displacement of the medium rather than vibrations in the medium. The use of this type of effect in fire detection is also discussed.
A new Ti:sapphire chirped pulse amplification system was established with three stage amplifiers. Pumping the final amplifier with a 100 J doubled-frequency Nd:glass laser, we generated stable 355 TW laser pulses at duration of 31 f s.