CLOUD SEEDING FLARES DR. N.V. SRINIVASA RAO

Cloud seeding, a form of weather modification, is the attempt to change the amount of precipitation that falls from clouds by dispersing substances into the atmosphere that serve as cloud condensator or ice nuclei which alters the microphysical processes within the cloud. The most common chemicals used for cloud seeding include silver iodide, dry ice; liquid propane. The use of hygroscopic materials; such as salt; is also getting attention. In a flare, hygroscopic material, pyrotechnic composition and initiating device are the components. The initiation device can be initiated by giving a electrical pulse. In turn initiation device will be initiating the pyrotechnic composition, which gives smoke with pressure. The hygroscopic material used in the composition will gets dispersed in the atmosphere through the smoke which acts as a nuclei for precipitation.

PREPARATION OF COMPOSITION: All the raw materials are powdered finely and sieved through required mesh. Fine powders are used. Hygroscopic material is to be ground to very fine powder and immediately packed in a cover with proper sealing. It should not be exposed to air. All the materials are to be dried at 100 deg. centigrade for one hour before use. The pyrotechnic composition contains an oxidiser, a fuel and a binding agent. Initially the pyrotechnic composition is mixed in a sigma mixer. Binding agent is taken first added fuel and then oxidiser and mixed for uniform mixing.

The dried hygroscopic material is added to the pyrotechnic composition and mixed thoroughly. The composition is to be properly sealed. PRESSING: The above composition is placed in the tube and pressed in a hydraulic press behind a safety shield and operation is repeated till required quantity is filled. Above this gun powder is pressed and fuse head is fixed above the composition and closed with disc.

Precautions to be taken during manufacturing 1 Precautions to be taken during manufacturing 1. Handle all the material behind safety shields only 2. Press the composition remotely 3. Don’t expose hygroscopic material to atmosphere. 4. Use all the personal protection equipment like asbestos suit, face shield; hand gloves etc. 5. Only authorised persons to handle the composition

6. Without permission from ex plosives dept no trials should be conducted. 7. Earth all the equipment used. 8. Use minimum quantity of material at a time. 9. Don’t expose the material to higher temperature. 10. Don’t drop the material from height

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