2025-01-13 Alicia Wills Testimony

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International Journal for Research in Engineering Application&Mana ement JREAM ISSN:2454-9150 6 concluded from their research that "a threshold is a device which converts electronic signals into acoustic velocity must be applied to the flame in order sound frequencies. Source of the electronic signal to achieve extinction, rather than a specific frequency is a DC current modified using integrated circuits. or acoustic pressure." However, it has been identified This signal passes through a coil located near a that this is not always the case. Frequencies between permanent magnet and connected to a flexible OHz to 10Hz do not prove to be effective in membrane. The signal causes rapid fluctuations in extinguishing flames,but frequencies between 30Hz to the surrounding magnetic field causing attraction 60Hz show promising signs in the same.Combustion is or repulsion from the fixed magnet, thus inducing a chemical process in which the substance rapidly vibrations in the membrane to generate sound. reacts with oxygen and gives out energy in the form of 2) The sound waves are further directed towards a heat and light. Acoustic fields have a significant effect subwoofer. The subwoofer is essentially a system on this process of combustion. When acoustic designed to play the lowest bass frequencies. It oscillations are combined with the vibrations of heat also has a built-in (active subwoofer) or an released from the fire, it alters the transportation external (passive subwoofer) amplifier. The process of combustion. subwoofer particularly amplifies the low frequency signals (30 Hz to 40 Hz) which are The light emitted by fire exhibits dual nature.Light can necessary for this experiment. act as a wave as well as a particle. This wave-particle 3) The low frequency sound waves are further duality of light is the focus of our consideration. The directed towards the vortex tube.A vortex tube is pressure waves emitted in the form of sound affect the basically a cylindrical object which has a air particles by pushing and pulling them away from stretchable membrane on one side and is open on the source of the flame.Also,at the proper frequencies, the other side. When sound waves are focused on the acoustic waves produced by the wave extinguisher this membrane, the membrane snaps forward and are going through a process of destructive interference collidesdirectly with the air molecules. This to interrupt the natural behaviour of the flame. accelerates the air molecules towards the other open end and sets off a continuous series of high- Fire in Space- speed collisions of air molecules. This rapid In outer space, fire reacts differently to that on the movement forms a stream or jet of air which is Earth. The fire formed in space has different shapes directed towards the fire. When the jet of air and properties due to presence of zero gravity. In escapes the opening of the vortex tube into the still space,fire flames are in the form of semi-circles with a air outside,it forms a`stable donut-shaped gaseous blue colour flame. Fire spreads from one air molecule projectile'.This is called a toroidal vortex or vortex to the other. These air molecules act as heat ring, hence the name vortex tube. The toroidal propagation elements. This process of convection is vortex is caused by the friction of the jet of air with done by ventilation fans in the space station. In space, the edges of the tube's opening and the slow- the smoke caused by these fires is not directed towards moving air outside the tube. smoke detectors and thus there is less chance of 4) The stream of air escaping from the vortex tube detection of fire at space stations. Being able to thus proves useful in extinguishing fires as extinguish fires in space without the use of water or explained in the previous sections. any other chemicals is a real boon, but on the other hand generating sound waves would require electricity Tone Generator:Generates and astronauts would need to see the flames to aim the sound frequencies from sound waves at the exact point of source. electronic signals. Ultrasound- Subwoofer:Seperates and It has been seen that ultrasonic frequencies have an amplifies the low frequency effect on the chemical kinetics of any chemical reaction. sound waves. This high frequency(above 20000 Hz) is seen to cause excitation which will prove to aid combustion. It might also delay and perturb the chemical reaction which Vortex Tube:Generates stream of air using the low frequency depends on the bonding for the chemical compound for sound waves. the frequency under consideration. Actual effects of i ultrasound for extinguishing flames have not been studied yet as optimum results were obtained for a frequency range of 60 Hz. Fire:Stream of air directed extinguishes the fire. Experimental Procedure- Fig.1 illustrates the experimental procedure using a block diagram as shown- 1) A tone generator is used for producing sound frequencies. Tone generator or a signal generator 231 AMET_0006 @ MIT College of Engineering,Pune,Vol.04,Special Issue AMET-2018 DOI:10.18231/2454-9150.2018.1391