TOP POLLUTION RECORDED IN WORLD

CHERNOBYL NUCLEAR DISASTER (NUCLEAR POLLUTION) :

In April 26,1986, the melt down of the Chernobyl nuclear reactor, in Russia, has leaked out the radioactive rays and radioactive materials.

Effects :

1. In this Pollution nearly 2000 persons have been killed by the accident.

2. People suffered due to the illness such as, degeneration of the cells, severe bleeding, anemia, skin cancer.

3. Animals, Plants are also affected by nuclear radiation.

MINAMATA EPIDEMIC (1953) : MARINE POLLUTION ( CASE STUDY )

Minamata is a small coastal village in Japan. The Chisso Chemical Company, which produces vinyl polymer plastics used organomercurial compound. The industry released its effluent into Minamata sea. The effluent containing mercury ions is converted into methyl mercury, which is highly toxic.

The marine organisms like phytoplankton and zoo-planktons easily absorb the toxic methyl mercury compound. These organisms are consumed by small fishes and these are in turn consumed by large fishes. Finally the large fishes are consumed by human beings. Thus the poisonous chemical (methyl mercury) enter into the body of human beings through food chain.
MARINE POLLUTION CASE STUDY : GULF WAR

The Gulf war took place in Kuwait from January 16 to February 26, 1991 between Iraq and USA. During The war American fighters dropped nearly a lakh of bombs and forced the Iraqi army to withdraw from Kuwait. During the retreat of Iraqi, they have set fire on nearly 700 oil wells of Kuwait.

Since most of the oils wells are on shore of the sea, oil from the oil well spills out into the sea. The floating oil over sea water covered nearly 80 km long and 25 km wide area.

The burning of oil wells continued nearly for 10 months. The burning of oil wells released huge amounts of pollutants like CO2 and SO2 into the atmosphere.

Effects :

1. Nearly one million birds have been killed due to the oil slick.

2. The oil slick in the sea made the desalination plants ineffective.

TORREY CANYON INCIDENT - MARINE POLLUTION :

Spilled oil, breaks down the natural insulating oils and waxes, which shield the birds from the water. Ultimately they loose their insulation, start shivering and freeze to death in winter.

About 30,000 birds died in Torrey canyon incident . Nearly 150 rare species of bald eagles also became victims when they ingested oil during Exxon valdez accident.

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ELECTRICAL COMPARATORS AND ITS WORKING

Electrical Comparators are used as a means of detecting and amplifying small movements of a work contacting elements. An electrical comparator consists essentially of a pick-up head or transducer for converting a displacement into a corresponding change in current and a meter or recorder connected in the circuit to indicate the electrical change, calibrated to show in terms of displacement. Generally, an amplifier is needed to provide the requisite sensitivity and to match the characteristics of different parts of the circuit. Electrical comparators can be classified according to the electrical principle used in the pick-up head. Most of the comparators use either a differential transformer, an inductance bridge, a strain gauge or a capacitor as a means of detecting movement of the gauging element. There are different types of electrical comparators. One kind called an electrolimit gauge is used to check or measure the outside diameter of a roll. The object to be checked is place

Advantages And Disadvantages Of Air Refrigeration System :

Advantages Of Air Refrigeration : 1. The refrigerant used namely air is cheap and easily available. 2. There is no danger of fire or toxic effects due to leakages. 3. The weight to ton of refrigeration ratio is less as compared to other systems. Disadvantages Of Air Refrigeration : 1. The quantity of Refrigerant used per ton of refrigeration is high as compared to other systems. 2. The COP of the system is very low. Therefore running cost is high. 3. The danger of frosting at the expander valves is more as the air contains moisture content.

THROTTLE GOVERNING OF STEAM TURBINES

Steam Pressure at inlet to a steam turbine is reduced by throttling process to maintain the speed of the turbine constant at part load and hence this method of governing is called "Throttle Governing". Construction : Throttle governing system consists of a centrifugal governor, a lever , an oil pump , a pilot piston , control valve , a relay piston and a throttle valve. The throttle valve is moved by a relay piston. The relay piston is actuated by pilot piston control valve. There are two piston valves covering ports in the pilot piston control valve without any overlap. These piston valves are operated by lubricating oil supplied by a gear pump at 2 to 4 bar. The oil returns to the drain from this chamber. Working : When the turbine works on full rated load, the throttle valve will remain open. When the load is decreased, the energy output of the turbine becomes in excess and the turbine shaft speed increases. Hence, governor sleeve will lift. The upward movement of the

Mechinopedia For Mechanical Engineers

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