Minutes of Proceedings of the Institution of Civil Engineers, Volume 69


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Página 6 - Plates may be received or rejected without a trial of every thickness on the invoice. (7) The pieces of plate cut out for testings are to be of parallel width from end to end, or for at least 8 inches of length. When the plates are ordered by thickness, their weight is to be estimated at the rate of 40 Ibs.
Página 243 - ... of a second. It does not matter whether the mixture used is rich or weak in gas ; the rich mixture can be fired slowly and the weak one rapidly, just as may be required. The rate of ignition of the strongest possible mixture is so slow that the time of attaining complete inflammation depends on the amount of mechanical disturbance permitted.
Página 224 - Ibs. per square inch above the atmosphere. The motor-piston is now at the beginning of its out-stroke, and as it moves forward air from the reservoir enters the cylinder, but as it enters it is heated to 1,537° Centigrade, without rise in pressure ; the motor-piston sweeps through 2 cubic feet.
Página 6 - Fahrenheit, must stand bending in a press to a curve of which the inner radius is one and a half times the thickness of the steel tested. The strips arc all to be cut in a planing machine, and to have the sharp edges taken off.
Página 222 - From the reservoir the mixture enters into a cylinder, being ignited as it enters, without rise in pressure, but simply increased in volume, and following the piston as it moves forward, the return stroke discharges the products of combustion. 3. An engine in which a mixture of gas and air is compressed or introduced under compression into a cylinder, or space at the end of a cylinder, and then ignited while the volume remains constant and the pressure rises. Under this pressure the piston moves...
Página 227 - ... of heat into work. With any given maximum temperature the smaller the difference between that temperature and the temperature of compression, the greater is the proportion of added heat converted into work with any given amount of expansion.
Página 225 - Ibs. above the atmosphere. This is shown at Fig. 1, and also at Fig. 4, which is the diagram of this type of engine, abcd is the compression diagram ; ab ef the motor diagram. The piston continues to move forward, and the air expands doing work. At the end of the stroke the pressure has fallen to 8.4 lbs.
Página 227 - That is, in an engine of type 1, if 100 heat-units be used, 21 units will be con verted into mechanical work. In type 2, with the same amount of heat, 36 units will be given as work, and in type 3 no less than 45 units would be converted into work. The great advantage of compression over no compression is clearly seen, by the simple operation of compressing before heating ; the last type of engine gives for the same expenditure of heat 2.1 times as much work as the first. Compression, as used by...
Página 224 - Centigrade is taken in, compressed without loss of heat, the temperature rising under the compression to 217°'5 Centigrade. When it is equal to the pressure in the reservoir it is forced into the reservoir, as is shown on the line b c. In all the operations no loss or gain of heat is assumed, except in doing work or in work being done on the air. In the motor-diagram from C to E the air is flowing from the reservoir following the piston, and the temperature is 1,537° Centigrade during the whole...
Página 6 - Strips cut lengthwise or crosswise of the plate to have an ultimate tensile strength of not less than 26, and not exceeding 30 tons per square inch of section, with an elongation of 20 per cent in a length of 8 inches.

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