A visual time signal in the form of a ball. Before the widespread use of radio time signals, time balls were dropped, usually at local noon, from conspicuously-located masts in various ports. The accuracy of the signal was usually controlled by a telegraphic time signal from an observatory.
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SEQUESTER
To form a stable, water-soluble complex.
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BALL BEARING
An anti-friction rolling type bearing containing rolling elements in the form of balls.
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CLOUD POINT
The temperature at which waxy crystals in an oil or fuel form a cloudy appearance.
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CRACKING
The process whereby large molecules are broken down by the application of heat and pressure to form smaller molecules.
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ACCELERATION
The time rate of change of velocity; i.e., the derivative of velocity; with respect to time.
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RUNNING TIME
Amount of time an unit, equipment or system is run per hour or per 24 hours.
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DEMULSIBILITY
The ability of a fluid that is insoluble in water to separate from water with which it may be mixed in the form of an emulsion.
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GROUP REPETITION INTERVAL
The specified time interval of a Loran C chain for all stations of the chain to transmit their pulse groups. For each chain a minimum group repetition interval (GRI) is selected of sufficient duration to provide time for each station to transmit its pulse group and additional time between each pulse group so that signals from two or more stations cannot overlap in time anywhere within the coverage area. The GRI is normally stated in terms of tens of microseconds; i.e., the GRI having a duration of 79,900 microseconds is stated as 7900.
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HARMONIC FUNCTION
Any real function that satisfies a certain equation. In its simplest form, as used in tide and tidal current predictions, it is a quantity that varies as the cosine of an angle that increases uniformly with time
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HOUR-GLASS EFFECT
A radarscope phenomenon which appears as a constriction or expansion of the display near the center of the plan position indicator, which can be caused by a nonlinear time base or the sweep plot starting on the radar indicator at the same instant as the transmission of the pulse. The phenomenon is most apparent when in narrow rivers or close to shore.
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