CHECK OUT WHY DOES A 100CC BIKE HAVE A 140KM/H SPEEDOMETER WHILE ITS TOP SPEED ONLY 80-90KM/H !!

The actual reason is VISIBILITY.

Lets consider a standard analog speedometer.

Even though the bike has top speed of about 70–75kmph. Even downhill speed may go up to 90kmph (when gear is engaged, even downhill speed is controlled by highest engine speed). The speedometer is marked up to 120kmph. The reason is, if the speedometer was marked only up to 80–90kmph, the needle would point extreme right. The time taken to find that needle by the user and register the corresponding number value in the mind would be quite high. At the same time, in the current set-up, the needle is dead in the middle. i.e. we can see it and understand the situation much faster. This time gap may be the difference between a near miss and accident.

Even in a circular speedometer as given below,

The speedometer and tachometer, both have similar concept. You are supposed to shift up when the tachometer needle is at center. Similarly, the speed is above normal if the needle is straight or above straight in the speedometer.

Even in industrial gauges, we set the middle as green region, left and right as red region. So whenever there is inspection, all the inspector has to check is if the needle is straight or not. If it is straight, it is OK. Otherwise, Not OK. Simple.

CHECK OUT WHY IN A THREE PIN PLUG THE EARTH PIN IS THICKER AND LONGER THAN OTHER PINS!!

When we use electrical appliances with metal bodies, we require protection against possible electric shock. If there is a fault current (leakage) inside the appliance, the whole metal case becomes live. If you happen to touch it, a current will flow through you to the earth (ie. electric shock). 

Hence, to prevent electric shock, we need to ensure that the system is properly earthed (= 'grounded'). This way if you touch a faulty appliance, you don't get electrocuted!

So, why is the earth pin made bigger?

1. The earth pin on a plug is longer than the live and neutral pins. This means the earth pin is the first to connect and the last to disconnect. 

• When inserting the plug, the earth connection is made before the current carrying contacts of the plug become live.
• When withdrawing the plug, the current carrying contacts shall separate before the earth connection is broken.

Thus, the earthing connection is always maintained to improve safety.

2. Many wall sockets have safety shutters (see image) on the live and neutral lines to prevent children from inserting conducting materials which may result in electric shock. Insertion of a longer (earth) pin helps in opening the shutters, facilitating the insertion of other two pins. These are called Earth-pin operated shutters.

3. Though it is impossible to insert the plug into the socket upside down, one may try to insert the plug top in a misaligned position (for e.g. trying to insert the earth pin into the phase socket with the other two pins further down out of the socket). Hence, the earth pin is made thicker so that even by mistake it cannot be inserted into the live or neutral hole of the socket. This prevents earth pin from establishing an electrical contact with the live terminal.

As we can see, every effort is taken to protect you from electric shock.

FORMING OPERATION EXPLAINED !!

Introduction :-

Materials are converted into finished products though different manufacturing 
processes. Manufacturing processes are classified into shaping [casting], forming, joining, and coating, dividing, machining and modifying material property. Of these manufacturing processes, forming is a widely used process which finds applications in automotive, aerospace, defense and other industries.
Wrought forms of materials are produced through bulk or sheet forming operations. Cast products are made through shaping – molding and casting.
A typical automobile uses formed parts such as wheel rims, car body, valves, rolled shapes for chassis, stamped oil pan, etc.

Forming is the process of obtaining the required shape and size on the raw material by subjecting the material to plastic deformation through the application of tensile force, compressive force, bending or shear force or combinations of these forces.

Classification of Forming Process :-

Typically, metal forming processes can be classified into two broad groups. One is bulk forming and the other is sheet metal forming. 


Bulk deformation refers to the use of raw materials for forming which have low surface area to volume ratio. Rolling, forging, extrusion and drawing are bulk forming processes. In bulk deformation processing methods, the nature of force applied may be compressive, compressive and tensile, shear or a combination of these forces.

Bulk forming is accomplished in forming presses with the help of a set of tool and die. Examples for products produced by bulk forming are: gears, bushed, valves, engine parts such as valves, connecting rods, hydraulic valves, etc.

Sheet metal forming involves application of tensile or shear forces predominantly. Working upon sheets, plates and strips mainly constitutes sheet forming. Sheet metal operations are mostly carried out in presses – hydraulic or pneumatic. A set of tools called die and punch are used for the sheet working operations. 

Bending, drawing, shearing, blanking, punching are some of the sheet metal operations.

Forming is also classified as cold forming, hot forming or warm forming. Hot forming is the deformation carried out at temperatures above recrystallization temperatures. Typically, recrystallization temperatures for materials ranges from 0.5 Tm to 0.8 Tm, where Tm is melting temperature of material.

FOUR WHEEL DRIVE VS ALL WHEEL DRIVE EXPLAINED !!

The 4WD and AWD are pretty much same, but have some variations each works best under certain conditions.

Four Wheel Drive

• It’s the oldest one, which has two options in terms of how and when torque is supplied to each wheel called Full time 4WD and Half time 4WD. Power from the engine goes to transfer case, which splits the power between the front and rear axles so that torque is evenly applied to each wheel
• It’s axles doesn’t rotate at the same speed, the option is available to choose what we need whether the torque needed for 2 wheels or 4 wheels.
• It’s good for Off road vehicles, Pickup trucks, terrain running vehicles where torque plays major role.
• It has locking differential option which gives more traction power to the wheels in off roads.
• This rugged technology has an option to turn off the drive to improve fuel economy.
• It might be dangerous once back on Tarmac from off road.
• Used in Jeeps, Landrovers, Pickup trucks.

All wheel drive

• AWD is a car system while 4WD is a truck system, the recent innovation which is AWD drive system is on all the time used in all the cars like Audi, Nissan GTR, Mercedes-Benz E63 AMG .These are all good examples for AWD.
• ECU(Electronic control Unit) Plays a major role in the AWD system sensors on each wheel monitor traction, wheel speed, and several other data points and decide to send the power to which wheel depends to maximise the grip and driveability.
• This best AWD sends the power to each wheel using a front rear torque - split system cutting the power from the wheel to the least traction. Most of the time rear wheels have the power to move the vehicle forward and from front wheels moves freely to improve fuel economy.
• The latest technology in AWD use variable torque distribution system.
• Provides increased grip and control under all road condition, gives sportier handling and traction to a broader range of cars. Good in snowy roads, performance oriented cars.
• Not good for off road and fuel economy is less.

9 THINGS TO KNOW BEFORE BUYING A USED MOTORBIKE !!

Not everyone can afford to buy a new motorcycle in their fist year of joining a job that pays them on the basis of a fresher who has just entered college finishing their high schooling and it is also not always about new bikes being better than the used ones. Blame the perception here for an instance.

In India although used bikes doesn’t strike the right chord with the buyers as it’s mostly seen negative, there are several instances where a used bike has proven itself a lot worthier for the money spent on it rather than a shiny one parked in the showroom waiting to be rolled down the ramp. 

The First and foremost thing being the bike itself that takes the centre stage, it is better that the buyer is on his own in inspecting the bike himself for the loop holes and definitely not rely someone who he hardly knows.Some very important pointers to look out for when buying a used motorcycle in your own local region that you belong to;

• Check the Papers of the vehicle, which to be very specific will be the Registration Certificate and the Insurance papers are valid and have not expired which in a case of an exotic like a Jawa belonging to 1970’s might not be which can be compromised at buyers own risk. Make sure the registration certificate carries the correct engine & chassis no. that is punched onto the bike. As this makes sure that the bike isn’t suffering from illegal issues and ensures that the piece of love that you’ve been looking for is pretty legitimate.

• Call up the Insurance agency the bike is registered to and with the help of a little Rapport that you create instantly with them, try and track down if any major claims/ accidents have been registered in the name of the owner or in the registration no. of the bike. This will make sure that the owner is not pushing you a troublesome salvage bike that might have its own legal issues once bought.

• Avoid a modified Motorcycle as modification in India is not as clean as it is seen abroad. Also modified motorcycle can also be a sign of an abused motorcycle that was modified from its original state to take some amount of abuse for whatever reason the owner did it with. Also modified motorcycles will be a Cop/ RTO authority magnet. It’s always better to be subtle than to shout out crying for unwanted attention.

• The frame, forks, engine casings and the fuel tank are the most expensive parts housed in a motorcycle excluding the engine itself. A detailed inspection of the above said things will save you a lot of money in terms of maintenance as damaged forks or fork oil seals or even a leaky tank that leaks once the kick stand is on will again drill a hole in the pocket after the deal is closed that puts a lot of financial pressure to the potential buyer.

• After the bike is visually inspected and when you’re satisfied, proceed to firing the engine. For a safer side, request the owner to start the bike. Keep the bike idling in stationary position. Listen to the engine idle, sharp ears and a good knowledge about Motors will be of a great help. If not pls. call your best mentor in the Automotive field whom you can trust with their decisions and rely them for the final verdict. In general, make sure the bike doesn’t let out too much of exhaust smoke in case of a 4 Stroke and if does, be prepared to look out for other options as a damaged cylinder kit will again cost you thousands additionally.

• If everything goes alright with respect to the engine idle, request the owner to rev up a little and inspect the same. If ok, ask the owner for a small test drive and pls. be polite to take him along if he insists as he would also feel that you are a complete stranger to him. Mutual respect is sincerely advised in this case.

• If something goes wrong or if you feel something is wrong during the test ride, pls. feel free to ask the owner about the same. With the answers given by the owner one can be clearly judge the intentions of the seller. Either it should be a legitimate sale or pushing off a rusted piece of metal.

•  The final stage being the owner and the negotiation part, make sure the owner feels as important as the vehicle itself that you’ve been looking out for. With that kind of feeling subjected to, the owner of-course will be very co-operative in answering almost any question that you throw at him right from the free services availed to the last repair and accident history carried out recently.

• Coming to the negotiations, make sure you enquire the local market price with respect to the year of manufacturing before you offer your deal. Be very polite in the offers and please avoid low balling as much as possible as most of the owners who have kept their machines in spanking conditions wanting to sell do not part them only because of the need for money. They might look out for better homes to put their long trusted steed in.

CAPILLARY ACTION EXPLAINED !!

Capillary action (or capillarity) describes the ability of a liquid to flow against gravity in a narrow space such as a thin tube.

This spontaneous rising of a liquid is the outcome of two opposing forces:

Cohesion – the attractive forces between similar molecules or atoms, in our case the molecules or atoms of the liquid. Water, for example, is characterized by high cohesion since each water molecule can form four hydrogen bonds with neighboring molecules.

Adhesion – the attractive forces between dissimilar molecules or atoms, in our case the contact area between the particles of the liquid and the particles forming the tube.

The capillarity of the liquid is said to be high when adhesion is greater than cohesion, and vice versa. Hence, knowledge of the liquid is not sufficient to determine when capillary action will occur, since we must also know the chemical composition of the tube. These two, together with the contact area (the tube's diameter), comprise the key variables. For example, water in a thin glass tube has strong adhesive forces due to the hydrogen bonds that form between the water molecules and the oxygen atoms in the tube wall (glass = silica = SiO₂). In contrast, mercury is characterized by stronger cohesion, and hence its capillarity is much lower.

So what's going on here?

In case the forces of adhesion are greater than those of cohesion and gravity (when it exists), the molecules of the liquid cling to the wall of the tube. We will observe that the upper surface of the liquid becomes concave (the height of the liquid at the contact area is higher than its height at the center of the tube). The cohesive forces between the molecules of the liquid are "attempting" to reduce the surface tension (i.e. to flatten the upper surface of the liquid and thus prevent the increased surface area in the concave state). In doing so, the molecules keep climbing up until a steady state between cohesion and adhesion is achieved (with or without the gravity component)

.

This also explains why this phenomenon occurs exclusively in thin tubes (also in the absence of gravity). In wider vessels, only a small fraction of the liquid comes into contact with the vessel walls, and so adhesive forces are negligible and there is hardly any rising of the liquid.

Many everyday phenomena are a result of capillary action, including:

(1) A kerosene lamp or a candle "sucking up" oil or liquid wax, respectively.

(2) Water climbing up the microscopic fibers of paper towels.

(3) Located at the inner ends of each eye, the lacrimal ducts drain our tears using capillary action.

TECHNICAL TERMS OF GAS TURBINE EXPLAINED !!

1.)NET JET THRUST – That part of the thrust of a turbojet engine which is available for climb and acceleration.

2.)NOZZLE – A flow passage specially shaped to produce kinetic energy at the expense of other forms of energy (available thermal energy).

3.)NOZZLE EFFICIENCY – The ratio of the actual kinetic energy produced on discharge (or between any two points in a nozzle) to that obtainable by assuming an isentropic expansion in the nozzle.

4.)OVERALL EFFICIENCY OF PROPELLER UNIT – Product of the propeller (propulsion) efficiency, thermal efficiency of the engine (power turbine) and the transmission efficiency from prime mover to propeller shaft.

5.)POLYTROPIC EFFICIENCY – The isentropic efficiency of an elemental stage of the compression which is constant throughout the process.Also called the SMALL STAGE EFFICIENCY.

6.)POWER RATIO – Ratio of useful or net horse power of the cycle compared with the power developed by the turbine of the system. Also called WORK RATIO.

7.)PREWHIRL – Whirl velocity (tangential component of the absolute velocity at intake), imparted to the air that enters the centrifugal compressor impeller, by allowing the air to be drawn into the impeller eye over curved inlet guide vanes attached to the impeller casing.

8.)PRIMARY AIR – Part of the air which flows through the core of the combustion chamber, in just sufficient quantity for combustion.

9.)PROPULSION EFFICIENCY – Ratio of thrust power to the jet power.

10.)RAM EFFECT – The effect which causes an increase of temperature and pressure of the air that enters the compressor of an aircraft gas turbine unit due to aircraft speed. Sometimes called RAM.

TECHNICAL TERMS OF GENERAL MECHANICAL ENGINEERING !!

1.)FILLET – A concave surface connecting the two surfaces meeting at an angle.

2.)FLANGE– A metal part which is spread out like a rim, the action of working
a piece or part to spread out.

3.)FLANK (Side of thread) – The straight part of the thread which connects the crest with the root.

4.)INVOLUTE GEAR TOOTH – A curved tooth generated by unwinding a string from a cylinder to form the curve.

5.)JOURNAL – The part of a shaft or axle that has been machined or finished to fit into a bearing.

6.)KEYS – Metal pieces of various designs that fit into a slot in a shaft and project above the shaft to fit into a mating slot in the center hole of a gear or pulley to provide a positive drive between the shaft and the gear or pulley.

7.)LOCK NUT – A type of nut that is prevented from loosening under vibration.The locking action is accomplished by squeezing, gripping or jamming
against the bolt threads.

8.)LOOSE PULLEY – A pulley which turns freely on a shaft so that a belt can be shifted from the driving pulley to the loose pulley in order to stop a machine driven by an overhead belt drive. 

9.)QUILL – A hollow shaft that revolves on a solid shaft carrying pulleys, gears or clutches. When the clutch is closed, the quill and shaft revolve together.

10.)RACK – A straight metal strip having teeth that mesh with those of a gear to convert rotary into reciprocating motion or just the opposite.

SURFACE TENSION EXPLAINED !!

Surface tension is a phenomenon in which the surface of a liquid, where the liquid is in contact with gas, acts like a thin elastic sheet. This term is typically used only when the liquid surface is in contact with gas (such as the air). If the surface is between two liquids (such as water and oil), it is called "interface tension."

Simply we can say,it is  property of a liquid surface displayed by its acting as if it were a stretched elastic membrane. This phenomenon can be observed in the nearly spherical shape of small drops of liquids and of soap bubbles. 

CAUSES OF SURFACE TENSION

Various intermolecular forces, such as Van der Waals forces, draw the liquid particles together. Along the surface, the particles are pulled toward the rest of the liquid, as shown in the picture to the right.

Surface tension depends mainly upon the forces of attraction between the particles within the given liquid and also upon the gas, solid, or liquid in contact with it. The molecules in a drop of water, for example, attract each other weakly. Water molecules well inside the drop may be thought of as being attracted equally in all directions by the surrounding molecules. However, if surface molecules could be displaced slightly outward from the surface, they would be attracted back by the nearby molecules. The energy responsible for the phenomenon of surface tension may be thought of as approximately equivalent to the work or energy required to remove the surface layer of molecules in a unit area. Surface tension may be expressed, therefore, in units of energy (joules) per unit area (square metres). Water has a surface tension of 0.07275 joule per square metre at 20 °C (68 °F). In comparison, organic liquids, such as benzene and alcohols, have lower surface tensions, whereas mercury has a higher surface tension. An increase in temperature lowers the net force of attraction among molecules and hence decreases surface tension.

Units of Surface Tension

Surface tension is measured in SI units of N/m (newton per meter), although the more common unit is the cgs unit dyn/cm (dyne per centimeter).

In order to consider the thermodynamics of the situation, it is sometimes useful to consider it in terms of work per unit area. The SI unit in that case is the J/m² (joules per meter squared). The cgs unit is erg/cm².

These forces bind the surface particles together. Though this binding is weak - it's pretty easy to break the surface of a liquid after all - it does manifest in many ways.

EXAMPLES OF SURFACE TENSION:

Drops of water. When using a water dropper, the water does not flow in a continuous stream, but rather in a series of drops.

The shape of the drops is caused by the surface tension of the water. The only reason the drop of water isn't completely spherical is because of the force of gravity pulling down on it. In the absence of gravity, the drop would minimize the surface area in order to minimize tension, which would result in a perfectly spherical shape.

Insects walking on water. Several insects are able to walk on water, such as the water strider.

Their legs are formed to distribute their weight, causing the surface of the liquid to become depressed, minimizing the potential energy to create a balance of forces so that the strider can move across the surface of the water without breaking through the surface. This is similar in concept to wearing snow shoes to walk across deep snowdrifts without your feet sinking.

Needle (or paper clip) floating on water. Even though the density of these objects are greater than water, the surface tension along the depression is enough to counteract the force of gravity pulling down on the metal object. Click on the picture to the right, then click "Next," to view a force diagram of this situation or try out the Floating Needle trick for yourself.

Surface tension is also viewed as the result of forces acting in the plane of the surface and tending to minimize its area. On this basis, surface tension is often expressed as an amount of force exerted in the surface perpendicular to a line of unit length.

TECHNICAL TERMS OF ENGINE !!

1.)CRITICAL COMPRESSION RATIO – Lowest compression ratio at which any particular fuel will ignite by compression under prescribed test procedure. The lower the critical compression ratio the better ignition qualities the fuel has.

2.)DEGREE OF ATOMIZATION– is indicated by the smallness of the size of the particles in the spray and also by the smallness of the variation in the size of the particles.

3.)DELAY PERIOD – Time interval between the start of injection and begining of combustion as indicated by a rise in the pressure crank angle curve, from the curve which represents compression and expansion of air while motoring. Also called IGNITION DELAY.

4.)DIRECT INJECTION ENGINES– have a single open combustion chamber into which the entire quantity of fuel is injected directly.

5.)OPTIMUM INJECTION ADVANCE – Fuel injection timing before TDC which will result in minimum ignition delay.

6.)RESIDUAL PRESSURE – The pressure at which the fuel is retained in the fuel line when the injector needle valve and the pump delivery valve are in the closed position.

7.)SAC VOLUME– is the dead volume between the nozzle seat and the end of the spray holes, in a multi hole injector.

8.)SOLID INJECTION SYSTEM – The system which injects only the metered quantity of fuel by means of a pumping device. Also called AIRLESS INJECTION SYSTEM.

9.)UNIT INJECTOR – A combined fuel injection pump and fuel nozzle.

10.)VALVE CLOSING PRESSURE– is the fuel pressure at which the fuel injector needle valve snaps back on its seat. For the differential valve stem, this is less than the nozzle opening pressure.

COUPLING AND ITS TYPE EXPLAINED !!

Couplings are used to connect two shafts for torque transmission in varied 
applications. It may be to connect two units such as a motor and a  generator or it may be to form a long line shaft by connecting shafts of standard lengths say 6-8 m by couplings. Coupling may be rigid or they may provide flexibility and compensate for misalignment. They may also reduce shock loading and vibration.

However there are two main types of couplings: 

(a.)Rigid couplings 
(b.)Flexible couplings 
Rigid couplings are used for shafts having no misalignment while the flexible couplings can absorb some amount of misalignment in the shafts to be connected.

Rigid couplings:

1.Sleeve coupling 

One of the simple type of rigid coupling is a sleeve coupling which consists of a cylindrical sleeve keyed to the shafts to be connected.Normally sunk keys are used and in order to transmit the torque safely it is important to design the sleeve and the key properly. The key design is usually based on shear and bearing stresses.


2.Clamp coupling 

A typical clamp coupling is shown in  figure. It essentially 
consists of two half cylinders which are placed over the ends of the shafts 
to be coupled and are held together by through bolt.

3.Ring compression type couplings 

The coupling consists of two cones which are placed on 
the shafts to be coupled and a sleeve that fits over the cones. Three bolts are used to draw the cones towards each other and thus wedge them  firmly between the shafts and the outer sleeve.

4.Flange coupling 

It is a very widely used rigid coupling and consists of two flanges keyed to 
the shafts and bolted.

Flexible coupling
As discussed earlier these couplings can accommodate some 
misalignment and impact. A large variety offlexible couplings are available 
commercially and principal features of only a few will be discussed here.

1.Oldham coupling 

These couplings can accommodate both lateral and angular misalignment 
to some extent. An Oldham coupling consists of two flanges with slots on 
the faces and the flanges are keyed orscrewed to the shafts. A cylindrical piece, called the disc, has a narrow rectangular raised portion running 
across each face but at right angle to each other. The disc is placed 
between the flanges such that the raised portions fit into the slots in the 
flanges. The disc may be made of flexible materials and this absorbs 
some misalignment.

2.Universal joints 

These joints are capable of handling relatively large angular misalignment 
and they are widely used in agricultural machinery, machine tools and 
automobiles.

3.Pin type flexible coupling 
One of the most commonly used flexible coupling is a pin type flexible 
flange coupling in which torque is transmitted from one flange to the other 
through a flexible bush put around the bolt.These are used when excessive misalignment is not expected such as a coupling between a motor and a generator or a pump mounted on a common base plate.

TECHNICAL TERMS OF SURFACE TREATMENT EXPLAINED !!

1.)CHROMIUM PLATING – Electrolytic deposition of chromium on a metal surface, as a protection against corrosion, to provide improved wearing properties, or to build up an undersize part.

2.)CHROMIZING – Similar to carburizing. Low carbon steel parts are packed with a mixture of alumina and chromium powder and heated in a hydrogen atmosphere, forming a surface layer of chromized material of 10 to 20% chromium, according to time and temperature of heating

3.)CALORIZING – Rust proofing process for ferrous metals in which an aluminium film is formed on the surface of the metal. Means of protecting iron from oxidation at elevated temperatures.

4.)ELECTROLYTIC POLISHING – Method of polishing metals in which the work forms the anode of an electrical circuit, and is suspended in a suitable bath of acid.

5.)ELECTROPLATING – Deposition of a metal on a surface by electrolytic action.

6.)FLAME HARDENING – Process of hardening by which steel or cast iron is raised to a high temperature by a gas torch flame and then almost immediately quenched.

7.)GALVANIZING – Rust prevention treatment which consists of coating the metal (iron or steel) with a fairly thick film of zinc.

8.)HARDENING – Process of increasing the hardness of a ferrous alloy by austenitizing and quenching, also the process of increasing the hardness of some stainless steels and non-ferrous alloys by solution heat treatment and precipitation.

9.)INDUCTION HARDENING – Heating the surface of cast iron or tool steel by means of electromagnetic currents followed by a quench.

10.)LACQUERING – A protective coat given to an article to prevent the polished surface from tarnishing, to prevent oxidation or to improve the general appearance and make the article more pleasing to the eye, and hence more saleable.

CHECK OUT WHY DO SOME FORMULA 1 TYRES HAVE NO TREAD ON THEM !!

When you take the car for an MOT, one of the things they have to check for is the depth of tread left on your tyres. Anything below 1.6 millimetres is not allowed and can affect your breaking distance.

So why are some Formula 1 car tyres completely smooth?

The job of a tyre is to grip on to the road surface. Because the tyre is made of a very ‘grippy’ material there is a lot of friction between the tyre and the road. Friction is a very useful force that can slow you down and stop you slipping all over the place. Some Formula 1 cars use completely smooth tyres in dry weather. A completely smooth tyre has lots of contact between the rubber and the road so these smooth tyres give great grip for fast corners.

When you’re driving around in your hatchback in city, you can’t pull in at a pit-stop to have your tyres changed when the clouds open, so normal cars need tyres that can grip in all weathers. The tread patterns on the rubber do not help with grip, but are there to channel water off the road. If you let your tread get too shallow, the water can’t go anywhere and the wheels can skim along over the surface of the water. This is called ‘aquaplaning’ and is nasty for a car on any road, but could be much worse for a Formula 1 driver because of the speeds that they drive. So they can choose from a whole range of tyres to use during a race depending on the weather. Dry weather races are usually faster and more exciting because of the extra grip the smooth tyres can give on the race track.

CHECK OUT THE REASON BEHIND U-SHAPED PIPE BELOW WASH BASIN SINK !!

Do you know why the pipe below the wash basin (sink) is U-shaped?

The U-shaped pipe can be seen in the above picture.

It has a very special purpose. Since there is a little bend in the pipe, some amount of water always stays in the bend (as you can see in the picture).When you run water down the drain, gravity forces the water through the curve and out the sewer pipe. When you turn off the faucet, some water gets trapped in the U-shaped part of the pipe, forming a water seal. The water completely fills the bottom curve this water acts as a barrier between the drain under the house and the sink above.

This will prevent any foul smell (sewer gas) from rising up into your home/office. This special pipe with a little bend is known as a P-trap.

Also,if you’ve ever dropped something valuable down the drain, like a ring or a house key, you know that curvy pipes can prevent lost objects from being lost forever. Many a ring has been fished out of the curve in a drainpipe, which often stops objects that fall down the drain from washing out the sewer. Although curvy pipes come in handy for trapping valuables, that’s not the main reason for the curves.

Important: If you smell something gross in your house, a defective P-trap in your kitchen/washroom could be the culprit.

TECHNICAL TERMS OF CUTTING TOOLS EXPLAINED !!

1.)CENTER REAMER – A countersink having a 60° included angle for sizing and smoothing center holes in workpieces to be turned or ground between centers.

2.)CERAMIC TOOLS – A newer cutting tool material made of aluminium oxide or silicon carbide and held together by binders or additives of other materials.

3.)CHISELS– These are hand working tools, made from carbon tool steel, usually of octagonal section. The end of the chisel is shaped to the required form and finished by grinding.

4.)COUNTERBORE– When a drilled hole is to be enlarged concentrically for a portion of its length, a counterbore is used. It consists of a series of blades arranged to cut on the ends only, and a smooth pilot slightly smaller than the drilled hole.

5.)DIE (drawing) – Tool of angular form through which a shell is pushed, tubes, sections, bar and wire are pulled so as to give the required size and cross-sectional shape.

6.)DOT PUNCH – Light type of sharply pointed centre punch used for light centre dotting along a scribed line to make it more easily visible or to ensure a permanent record of its location.

7.)END MILL – A milling cutter having a straight or tapered shank for mounting into a holder for driving. The cutting portion has teeth on the end as well as on the circumference.

8.)FLAT ENDED DRILL– by means of which a hole previously drilled to the correct depth with a twist drill may be squared out to a flat bottom, the small “pip” is necessary to ensure that the drill runs concentrically.

9.)FLUTED CHUCKING REAMER – A machine reamer which has straight or helical flutes to provide cutting edges over the entire length of the flutes. Intended for removing a small amount of metal and for finishing a hole accurately and smoothly.

10.)HOB – Fluted rotary cutter used to produce spur, helical, and worm gears, a worm shaped cutting tool having a number of flutes or gashes running across the threads so that a series of cutting edges is formed.

TECHNICAL TERMS OF HEAT TRANSFER EXPLAINED !!

1.)CELSIUS – The scale of changes of temperature which uses 0 degree as the freezing point and 100 degree as the boiling point for water at standard pressure.

2.)CHARLE’S LAW – At constant pressure, the volume of a gas is proportional to its absolute temperature. At constant volume, the pressure is proportional to its absolute temperature.

3.)CLOSED SYSTEM – The system which will have boundaries across which both heat and work can penetrate, but no mass will be permitted to cross them.

4.)Cp– Specific heat at constant pressure-Heat to be supplied to raise the temperature of 1 kg of gas through 1°C, the pressure being kept constant (in other words external work is done).

5.)Cv– Specific heat at constant volume-Heat to be supplied to raise the temperature of 1 kg of gas through 1°C, the volume being kept constant (in other words no external work is done).

6.)DALTON’S LAW OF PARTIAL PRESSURES – At a common temperature, a mixture of gases will exert on the sides of the vessel a total pressure equal to the sum of the pressures which each constituent would exert separately if it alone occupied the vessel.

7.)DRY SATURATED STEAM – Saturated steam, as generated from water, that contains no moisture in suspension.

8.)EQUIVALENT EVAPORATION – Amount of water in kg. that would be evaporated from water at 100°C into steam at 100°C and 1.03 kscm, by the heat put into steam actually evaporated in one hour by 1 kg of fuel.

9.)FACTOR OF EVAPORATION – A quantity which when multiplied by the amount of steam generated at a given pressure from water at a given temperature, gives the equivalent evaporation from and at 100°C.

10.)FLOW WORK – The product PV (pressure and specific volume) represents flow work in a steady flow system.