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Biosimilar is the term coined for protein drugs that are similar, but not identical to, an existing product. Copies of biopharmaceuticals (proteins) that can be made after the patent on the …Full description
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Homeschooling has become a controversial issue in recent years. Homeschooling opponents opine that it is not an alternative pathway for education alongside the standard public educational system because there are still many flaws existing in this sys
Adv 1.It gives a direct rotary motion and a more even torque on the propeller shaft. 2.There is no internal mechanical friction, and therefore no internal lubrication is required; this is most important when using superheated steam, the use of which in a reciprocating engine necessitates lubricating oil. Oil is difficult to remove from the feed water and is detrimental to boilers. 3 The weight of engine is reduced for the power developed, especially with large powers. (The weight of a turbine engine per kilowatt is about one half of that of a reciprocating engine.) 4. Steam is expanded right down to the condenser pressure, giving a higher overall efficiency. 5.The space occupied is less for turbines. Disadv 1. the condensing plant is larger and more expensive and requires greater auxiliary power due to the lower condenser pressure carried. 2.Special heat-resisting materials are required at the H.P. end for the rotor and casing if using high superheat. 3. A separate astern turbine is required which is mounted on the same spindle as the ahead turbine 4. A reduction gear is required to allow the turbine to run at the high speed necessary for high efficiency, and the propeller at the comparatively slow speed for its best efficiency. 5. The main bearings of the rotor work under severe temperature conditions due to the conduction of heat from the inside of the turbine casing, and all bearings, including the thrust, have a comparatively high surface speed. The lubricating system is, of necessity, more complicated, and must be absolutely reliable. 6. More expert attention is required during warming-up, draining and shutting down, due to the liability of rotors and casings distorting. Source Marine Steam Engines and Turbines S. C. McBIRNIE 2. What is the difference between reciprocating and turbine engine? The difference between the reciprocating engine and turbine engine is that, in the reciprocating engine the velocity of the
steam relative to the working parts (piston, etc.) is zero, while in the turbine engine the velocity of the steam relative to the working parts (blades, etc.) is very considerable, often of the order of 300 m/s. This simply means that the reciprocating engine uses pressure energy and the turbine uses velocity energy; or again, that in the reciprocating engine, work is done on the piston by the static pressure of the steam, while in the turbine work is done on the blades by the dynamic force of the steam.