A periodontist is a dentist who specializes in the prevention, diagnosis, and treatment of periodontal disease, and in the placement of dental implants. Periodontists are also experts in the treatment of oral inflammation.
Ground speed. Ground speed is the horizontal speed of an aircraft relative to the ground. An aircraft heading vertically would have a ground speed of zero. Information displayed to passengers through the entertainment system often gives the aircraft ground speed rather than airspeed.
Top Fuel Dragster (TF/D). The rail dragsters, or âdiggersâ, are the fastest class. Among the fastest-accelerating machines in the world, these cars can cover the dragstrip in less than 3.8 seconds and record trap speeds over 325 mph. Top Fuel cars are 25 feet long and weigh 2,320 pounds in race-ready trim. Methanol fuel mixed with up to 90% nitromethane is used.