A fumed-silica, which can make a slurry having sufficient wettability to a polar liquid, excellent dispersibility, and low viscosity even in the high concentration, and a slurry thereof. The channel estimator estimates a channel response from a received signal, and the channel calculator calculates a basic component of a channel response and fluctuating components of the channel response from the estimated channel response. The housing includes a display screen and a power button. Air is drawn through the manifold system and the plurality of conduits to capture dust generated during the movement of sand along the conveyor through the inlet of each of the plurality of conduits. After initial evaluation, the DAIS may be used to reevaluate some or all of the database andor the authority database established by the DAIS may be used to add or update information. Next the sender removes the first encryption, thereby allowing the receiver to reconstitute the original message by removing the second encryption.