This invention provides a high purity silica crucible having low impurity concentration in its inner portion, and its production method. According to the invention, the circular knitting machine has a dust removal device which contains air distribution channels which are configured in the segments and are connected to a compressed air source via radial air supply channels. After the user has entered the characteristics, the standardized reverse logic databank of the invention will cull out the items that have non-compatible characteristics and identify the item or provide a list of the possible identity matches for the unknown. Responsive to identifying the no-start flag being set, an error code is returned without starting the disk drive. The phased array antennas can be configured to produce beams that can be scanned in one dimension or two dimensions by using continuously adjustable phase shifters that are based on low cost, low loss voltage-tunable dielectric materials.