Disadvantages of In-Office Whitening. 1  In-office bleaching is more expensive than take-home alternatives. 2  Its cost, on average, is $650, compared to $400 for take-home trays and under $100 for over-the-counter bleaching trays or whitening strips.
Planetary protection is a guiding principle in the design of an interplanetary mission, aiming to prevent biological contamination of both the target celestial body and the Earth in the case of sample-return missions.
Protection of Thyristors with Snubbers. The regular way of protecting semiconductor elements from overvoltage is by arranging the resistors and capacitors directly in parallel to the individual switches. This ensures that the component is always protected regardless of where the overvoltage comes from. This method is however not always ideal.