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Class or degree of precision of anti-friction roller bearings.

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As defined by the International Telecommunication Union (ITU) for a given class of emission, the minimum value of the occupied bandwidth sufficient to ensure the transmission of information at the rate and with the quality required for the system employed, under specified conditions. Emissions useful for the good functioning of the receiving equipment as, for example, the emission corresponding to the carrier of reduced carrier systems, shall be included in the necessary bandwidth.


Of questionable accuracy. APPROXIMATE or SECOND CLASS may be used with the same meaning.


A ship of the same class as, and therefore virtually identical in design and appearance to another ship. Sister ships share an identical or nearly identical hull and superstructure layout, similar displacement, and roughly comparable features and equipment. Often, sister ships become more differentiated during their service lives as their equipment are separately altered.


Sodium bicarbonate powder is used to extinguish almost all types of fires but mostly on metal, or class D, fires. It is mainly located in the engine room and near electrical equipment.
2NaHCO3 ----> Na2CO3 + H2O + CO2
Construction: Dry powder extinguisher contains sodium bicarbonate powder in the outer container. A small container with carbon dioxide is placed beneath the plunger mechanism. Working: When the plunger is pushed, it releases the carbon dioxide gas, which in turn forces the dry powder out of the discharge nozzle.
Advantages: ABC Dry powder fire extinguishers are a multi-purpose and highly effective extinguishing agent, making them an excellent choice for use in many circumstances. As their extinguishing medium is dry they will not cause damage to items such as documentation in the way that wet types such as water or foam will.

a. Very fine powder residue that will disburse on discharge over a wide area and settle into every small place making the clean-up process of small fires more problematical.
b. The powder residue can cause damage to sensitive electronic equipment such as circuit boards, computers etc.
c. Dry powder introduces exposure hazards in three ways:
i. It causes irritation on contact with the skin.
ii. It causes irritation and discomfort on contact with eyes.
iii. It causes breathing discomfort on inhalation.
Refilling of DCP Fire Extinguishers:
Step 1: Unscrew the handle and remove the handle and main body.
Step 2: Unscrew the bottle of CO2 cartridge in the clockwise direction from the handle.
Step 3: Remove residues of DCP from the container.
Step 4: Clean the container thoroughly.
Step 5: Fill the container with fresh DCP.
Step 6: Screw the new CO2 cartridge to the handle in the anti-clockwise direction.
Step 7: Screw the handle and main body tightly.


Any of a class of chemical elements that are typically lustrous solids that are good conductors of heat and electricity.


A product, material or substance is a controlled product within the meaning of Class C if it meets either of two conditions that causes or contributes to combustion.


  1. The reference used to position limits of the territorial sea and the contiguous zone.
  2. One side of a series of connected survey triangles, the length of which is measured with prescribed accuracy and precision, and from which the lengths of the other triangle sides are obtained by computation. Important factors in the accuracy and precision of base measurements are the use of standardized invar tapes, controlled conditions of support and tension, and corrections for temperatures, inclination, and alignment. Base lines in triangulation are classified according to the character of the work they are intended to control, and the instruments and methods used in their measurement are such that prescribed probable errors for each class are not exceeded. These probable errors, expressed in terms of the lengths, are as follows: first order, 1 part in 1,000,000; second order, 1 part in 500,000; and third order, 1 part in 250,000.
  3. The line along the surface of the earth between two radio navigation stations operating in conjunction for the determination of a line of position.


A product, material, or substance falls into Division 6 of Class B if it meets either of two conditions;
1) It is spontaneously combustible under normal conditions of use and it emits a flammable gas or
2) it becomes spontaneously combustible on contact with water or water vapour.


1. A periodical publication of astronomical data designed primarily for air navigation, but often used in marine navigation. 2. A joint publication of the U.S. Naval Observatory and H. M. Nautical Almanac Office, Royal Greenwich Observatory, designed primarily for air navigation. In general the information is similar to that of the Nautical Almanac, but is given to a precision of 1' of arc and 1s of time, at intervals of 10m (values for the sun and Aries are given to a precision of 0.1').


A periodical publication of ephemeral astronomical data. If information is given in a form and to a precision suitable for marine navigation, it is called a nautical almanac. See also nautical almanac; if designed primarily for air navigation, it is called an air almanac. See also EPHEMERIS, ASTRONOMICAL ALMANAC.
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