For this reason, the bulk density of powders is usually reported both as "freely settled" and "tapped" density (where the tapped density refers to the bulk density of the powder after a specified compaction process, usually involving vibration of the container.)
http://en.wikipedia.org/wiki/Bulk_density

bulk density -> φαινόμενη/ φαινομενική πυκνότητα (ΙΑΤΕ)

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