The beads may be added to substances such as explosives in order to create a distinctive optical signature that identifies a manufacturer, lot number, etc. in the event of {HEAD ~ the need} for {TAIL ~ forensic analysis} 
for
The beads may be added to substances such as explosives in order to create a distinctive optical signature that identifies a manufacturer , lot number , etc . in the event of { HEAD ~ the need } for { TAIL ~ forensic analysis }
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