Electric clock

Abstract: Synchronous electric clocks utilize power grid frequency as their timing reference. Power grid frequency deviation away from its nominal value results in synchronous electric clocks running fast or running slow (also known as the time error). In this article, statistical analysis on time error of synchronous electric clocks around the world is firstly presented using the power grid frequency measurements recorded by the wide-area frequency monitoring network FNET/GridEye. Then, the time error correction (TEC) process provided by electric utilities is analyzed and the worldwide TEC practice is investigated. Eventually, regions of the world where electric utilities provide TEC service are differentiated from those without TEC services. Analytical results demonstrate that the average time error of synchronous electric clocks in North America seems to be less than five seconds, and it has not changed very much over the past few years. On the other hand, the identification results present that up to the end of 2016, many electric utilities around the world, especially in North America and Europe, provided the TEC service to periodically remove the accumulative time error of synchronous electric clocks.

Abstract: In alternating 12-hr periods of light and dark the rat is active mainly in the dark. Its activity in the dark (beginning at 1800) depends exclusively on release of activity by the 24-hr clock. In the light (beginning at 0600) the 24-hr clock inhibits activity; the normal rat becomes totally inactive in the light except for activity resulting from external stimulation. After section of the connections between the optic chiasma and the hypothalamus, some rats become totally and permanently inactive in the dark. This sectioning destroys the 24-hr clock. After destruction of the clock removes inhibition of activity in the light period, the rat becomes active promptly at start of the light period--i.e., becomes a "light-active" animal. In the normal rat, activity becomes synchronized to start of the dark (by the electric clock at 1800), regardless of the amounts of activity. Destruction of the 24-hr clock eliminates the synchronizer at 1800. However, almost at once, activity, eating, and drinking are kept together by a second synchronizer, start of the light (by the electric clock at 0600). This may explain the ability of the rat to survive after destruction of the 24-hr clock.

Abstract: A silent awakening system operable either by receiving a sound-alarm signal, such as that from a fire-detection alarm, or by the actuation thereof by means of an alarm-triggering means of an electric clock, with the sound-producing mechanism of said clock being deactivated. The system is used to awaken deaf persons as well as persons of normal hearing, without disturbing others sleeping in the same room or nearby. It comprises a sound-receiving means which converts said sound to an electric signal to operate an electric relay, an electrical signal-processing circuit connected to said relay and actuated thereby, an electric alarm clock to set the time of awakening with the alarm-triggering means thereof mechanically connected to a switch means disposed in said electrical signal-processing circuit, and an awakening module electrically connected to said electrical signal-processing circuit to receive, for operation thereof, a processed current either through said electric relay or through said switch means actuated by the alarm-triggering means of said clock.