FULL FORM RELATED TO W

FULL FORM RELATED TO W

WADA        :-       World Anti-Doping Agency

WANO        :-       World Association of Nuclear Operators

WAP           :-      Wireless Application Protocol

WAVE         :-      Wireless Access for Virtual Enterprise

WAY           :-      World Assembly of Youth

WDF           :-      Wasteland Development Force

WEF            :-      World Economic Forum

WFP            :-      World Food Program

WFTU          :-      World Federation of Trade Union

WGIG          :-      Working Group on Internet Governance

WIPRO        :-      Western Indian Products

WIPO          :-      World Intellectual Property Organization

WHO           :-      World Health Organization

WIDF           :-      Women's International Democratic Federation

WIPO          :-      World Intellectual Property Organization

WIPSA         :-      Women's Initiative for Peace in South Asia

WLL            :-      Wireless in Local Loop

WMD           :-      Weapons of Mass Destruction

WMO           :-      World Meteorological Organization

WR         :-      Western Railway

WTO            :-      World Trade Organisation (previously called GATT)

   :-      World Tourism Organisation

WWF            :-      World Wild Life Fund

WWFI          :-       World Wide Fund for Nature India

WWPA          :-      World Wild Life Protection Agency

WWW           :-      World Wide Web

WYSIWYG     :-      What you see is what you get

FULL FORMS RELATED TO X

FULL FORMS RELATED TO  X

XML             :-       Extensible Mark-up Language

FULL FORMS RELATED TO Y

FULL FORMS RELATED TO Y

YMCA          :-       Young Men's Christians Associations

YWCA          :-       Young Women's Christians Association

FULL FORM RELATED TO Z

FULL FORM RELATED TO Z

Z.A.P.U         :-       Zimbabwe Africa Peoples Union

ZBB              :-       Zero Base Budgeting

ZETA             :-       Zero Energy Thermo Nuclear Assembly

ZIFT             :-       Zygote Intra fallopian Transfer

ZIP               :-       Zone Improvement Plan

ZOPFAN         :-       Zone of Peace Freedom and Neutrality

Z.P.Z            :-       Zero Population Growth

ZS                :-       Zoological Society

ZUPO            :-       Zimbabwe United People's Organisation

Iron and Steel

Iron and Steel

history about : The Stone Age, Bronze age and Iron age are the three main era of human history. In the beginning man was making weapons like axe and sword, using stones. A sharpened stone was fitted in a wooden base and used. Then man invented bronze, from minerals having mixture of copper and zinc. Though, Copper was available, it was not useful for making weapons because of its soft & flexible nature. Bronze is hard. Therefore, it was used in most of the instruments. Use of iron started 2500 to 3000 years ago. In the beginning iron was obtained only from meteorites falling from the sky. Since Iron was scare, it was considered to be the most valuable metal. The process of producing iron from minerals was difficult and the iron received was hard and brittle. The technique of melting iron was known in our country from 1500-2000 years ago. Iron pillar Kutubminar in Delhi was built at the time of Chandragupta is a proof of it. Use of iron became common only after industrial revolution in England. Today, Worldwide production of iron is in thousand of crores tonnes.

Production

                    In nature iron is available in the form of minerals. These minerals are combination of iron, oxygen and sulphur. Iron is obtained from these minerals by following process.

Minerals (iron + oxygen) + (Carbon) = iron + (Carbon + oxygen) 

Minerals are heated in the oven over 1500oC. In the oven, Carbon and oxygen combines together to form carbon-di-oxide (CO2). This gas evaporates and iron remains in the oven. This liquid iron is solidified in moulds. Because of the shape of solid iron, it is called pig iron’. This iron is again melted and poured into different moulds to make different articles of cast iron. Cast Iron is hard but brittle in nature. It contains 3%–4% Carbon

Types of iron and steel

Steel-Iron gets combined with carbon to form steel. Properties of Steel are different from that of iron.

Following are types of iron steel: 

1) High Carbon Steel: Steel containing 0.6%–2% carbon is called high carbon steel. It is used to make tools. 

2) Cast Iron: Cast iron contains 3%–4% carbon. The cast Iron is hard in nature. You might be aware diamond is allotrope of carbon and it is very hard and used to cut glass. 

3) Mild Steel: It contains 0%–0.3% carbon. It is used in the production of iron shades, angles, rods, pipes etc. 

4) Stainless Steel: It is made of iron, chromium and nickel. Stainless steel does not stain, corrode, or rust as easily as ordinary steel. The price of stainless steel is more than the original metal. Stainless steel are commonly used in cutlery, utensil’s etc.

Heat Treatment

 As the percentage of carbon in steel increases, it becomes harder. Hardness of iron also changes with heat given to it. If steel is made red hot and then cooled rapidly then it becomes hard. If it cooled slowly then it become less hard. This is called heat treatment.

machine

MACHINE

Machines became part of our daily lives. Machines help us to reduce efforts required to do the work. All machines are based on the combination of ‘simple machines’. A simple machine is a mechanical device that changes the direction or magnitude of a force. Scissors, brakes, pulley, gears, inclined plane, screw etc. are the examples of simple machines.

an apparatus using mechanical power and having several parts, each with a definite function and together performing a particular task.

Following are the formula for defining relation between power , force, distance and time.

Power  = work / Time 

           = (force X distance) / Time 

           = force X speed

Power  = force X speed
Work   = force X distance. 

Friction and Lubrication

                                                           Some times there is screeching sound while using a pulley or hand pump. Friction is a force. Whatever work we do, friction works opposite to our force. When we apply a force to move something, the friction opposes our force and there is no motion. When our force is greater than the friction force, the object starts moving. The parts where there is friction, they wear out fast. A smooth surface shows lots of uneven and rough surface under a microscope. When these rough parts rub on each other, it results in friction. Oiling and greasing reduces friction and wear & tear of parts. When there is dust or foreign particles in the area of contact, friction and wear & tear are high and rapid. To prevent this, we must first clean the friction area and put oil or grease there. 

Friction is not always bad. Sometimes we require friction.

For example: 

1) While walking friction helps us. If we put oil on the floor, we will fall down due to slippery floor. We need friction to be able to walk. 

2) It is commonly seen that in muddy area the wheel of a truck slips round and round because there is no friction between the tyres and ground. 

3) Flour mill works because of friction between belt and wheel. 

4) Bicycle can be stopped by putting on a brake, which works because there is friction. 

5) When we tie a knot in a rope, it is the friction which holds the knot. Thus friction is useful to some extent but it will reduce the efficiency of work. 

Factors affecting friction

The intensity of friction depends on following factors:

 i) The area involved in friction.

 ii) The pressure applied on the surfaces. 

     Force = Pressure ´

    Area Frictional force will increase, if the area of contact will increase or if pressure applied on the surface increased. 

Methods to reduce friction

i) Polish the contact surface. 

ii) Put oil or grease so that it fills in the small gaps of the flat parts. 

iii) Use ball bearings to reduce area of contact between rotating parts.

Lubrication

                


  Following methods can be used to reduce friction: 

                                                                       Oil is either thin or viscous. It depends upon SAE No. of oil. (SAE means Society of Automotive Engineers). If we use very viscous oil, it does not reach all the parts. Very thin oil will flows away easily and gets wasted. Grease is used in such cases. It is generally used around ball-bearing. Normal grease or oil is never used where there is high pressure, high temperature and high speed. Special lubricants are used in such cases. In cold season the oil becomes thick and in hot season it becomes thin. Therefore selection of lubrication also depends on the season. It is always advisable to refer operating manual of the equipment before selecting the lubricant.