Semi-adjustable articulator with mounted casts. An articulator is a mechanical device used in dentistry to which casts of the maxillary (upper) and mandibular (lower) teeth are fixed, reproducing recorded positions of the mandible in relation to the maxilla.
The Greek scholar Heron of Alexandria created the earliest known automatic door in the 1st century AD during the era of Roman Egypt. The first foot-sensor-activated automatic door was made in China during the reign of Emperor Yang of Sui (r. 604â618), who had one installed for his royal library.
James Sargent advanced this idea even further by inventing the worldâs first key-changeable combination lock in 1857. Sargent made locks smarter when he created the worldâs first time lock, which would only open at a set time, and time-delay locks, which would only open after a certain interval, in 1873 and 1880, respectively.