Important Portals & their Founders

Some Important Portals & their Founders
1. Google — Larry Page & Sergey Brin
2. Facebook— Mark Zuckerberg
3. Yahoo— David Filo & Jerry Yang
4. Twitter— Jack Dorsey & Dick Costolo
5. Internet— Tim Berners Lee
6. Linkdin— Reid Hoffman, Allen Blue& Koonstantin
Guericke
7. Email— Shiva Ayyadurai
8. Gtalk— Richard Wah kan
9. Whats app — Laurel Kirtz
10. Hotmail— Sabeer Bhatia
11. Orkut— Buyukkokten
12. Wikipedia— Jimmy Wales
13. You tube— Steve Chen, Chad Hurley &
JawedKarim
14. Rediffmail— Ajit Balakrishnan
15. Nimbuzz— Martin Smink & Evert Jaap Lugt
16. Myspace— Chris Dewolfe & Tom Anderson
17. Ibibo — Ashish Kashyap
18. OLX— Alec Oxenford & Fabrice Grinda
19. Skype— Niklas Zennstrom,Janus Friis & Reid
Hoffman
20. Opera— Jon Stephenson von Tetzchner & Geir
lvarsoy
21. Mozilla Firefox— Dave Hyatt & Blake Ross
22. Blogger— Evan Willam Belli

Drive shaft

Drive shaft:-
A drive shaft, driveshaft, driving shaft, propeller shaft
(prop shaft), or Cardan shaft is a mechanical
component for transmitting torque and rotation,
usually used to connect other components of a drive
train that cannot be connected directly because of
distance or the need to allow for relative movement
between them.
Drive shafts are carriers of torque: they are subject
to torsion and shear stress, equivalent to the
difference between the input torque and the load.
They must therefore be strong enough to bear the
stress, whilst avoiding too much additional weight as
that would in turn increase their inertia.

supercharger

A supercharger is an engine-driven air pump that
supplies more than the normal amount of air into the
intake manifold and boosts engine torque and power.
It provides an instantaneous increase in power
without delay or lag associated with turbochargers.
Because it is driven by the engine, it requires
horsepower to operate and is not as efficient as a
turbocharger.
In basic concept, a supercharger is an air pump
mechanically driven by the engine itself. Gears,
shafts, chains, or belts from the crankshaft can be
used to turn the pump. This means that the air pump
or supercharger pumps air in direct relation to engine
speed.
types of supercharger
................................
-Roots-type supercharger :-
Named for Philander and Francis Roots, two brothers
from Connersville, Indiana, who patented the design
in 1860 as a type of water pump to be used in mines.
Later used to move air, and used today on two-
stroke cycle Detroit diesel and other supercharged
engines.
The roots-type supercharger is a positive
displacement design. All
air entering is forced through the unit.
-Centrifugal supercharger :-
Mechanically driven by the engine, similar to a
turbocharger but mechanically driven by the engine.
A centrifugal supercharger is not a positive
displacement pump and all of the air that enters is not
forced through the unit. Air enters a centrifugal
supercharger housing in the center and exits at the
outer edges of the compressor wheels at a much
higher speed due to centrifugal force.
Blade speed must be higher than engine speed so a
smaller pulley is used on the supercharger and the
crankshaft overdrives the impeller through an internal
gear box, achieving about seven times the speed of
the engine.
Examples of centrifugal superchargers include
Vortech and Paxton
Supercharger Service
Usually lubricated with synthetic engine oil inside the
unit, the supercharger oil level should be checked and
replaced as specified by the vehicle or supercharger
manufacturer. The drive belt should also be inspected
and replaced as necessary.

difference between Moment and Couple

What is the difference between Moment and Couple?
• Moment of force is the measure of turning effect of
a force about a point. A couple consists of two equal
and opposite forces acting with two different but
parallel lines of action. Each force has its own
moment.
• Moment of a force is dependent on the distance
from the pivot and the magnitude of the force while
the moment of a couple is the net effect of the two
moments of the forces. Moment of a couple is
independent of the location of the point considered. It
is constant throughout the plane. The resultant
moment of a couple is called a torque.
• Torque, also called moment or moment of force, is
the tendency of a force to rotate an object about an
axis, fulcrum, or pivot. Just as a force is a push or a
pull, a torque can be thought of as a twist.
Couple - Two equal but opposite forces
Torque - Moment of a couple

Carburetor used inAutomobiles

Automobile:
Which Carburetor used inAutomobiles?
A carburetor is a device used in petrol or similar
liquid fuel engines by means of which the fuel mixed
with air, is supplied into the induction manifold of the
engine. An engineering or automobile field connected
people will better know this. The main object of the
carburetor is to supply the required quantity of fuel
and air mixture of the correct strength as dedicated
by the load condition of the engine. For this purpose
different types of carburetorsare available in the
market. Out of that, you will find here the details of
Zenith Carburetor, as below. Zenith carburetor is also
known as “British Carburetor” and used by various
famous car manufacturers. This carburetor has also
number of designs available for different purposes.
Construction and Working
In this, float chamber is supplied with fuel from the
fuel tank through a pipe.Whenever the float chamber
falls short of fuel, the fuel from the fuel tank flows
into the chamber at a fastest speed than is consumed
by the engine with the result that, the float rises up, till
it reaches a certain level. At this time, a needle valve
moves down and rest against the seat, resulting the
stoppage of fuel supply from fuel tank.
The main jet is directly connected to the float
chamber while the auxiliary jet which is also called as
compensating jet draws fuel from auxiliary chamber
(Reservoir).Thi s auxiliary chamber is connected to
the float chamber through an orifice. Both, main and
auxiliary jet is openedup in the venturi.
The air to the carburetor is supplied through the
passage. The throttle valve is located at the end of
the carburetor and connected to the engine suction
pipe. The opening andthe closing of the throttle valve
controls the quantity of air-fuel mixture supplied to
the engine suction manifold. An auxiliary nozzle from
auxiliary chamber (Reservoir) is located at one end of
the by-pass and the other end of this nozzle, opens
upnear the throttle valve.
Working at Starting and Low Speed Running
Because of lower velocity of air at the time of starting
or slow speed of the engine, the suction produced at
the venturi is quite insufficient to operatethe main and
the auxiliary jet in nozzle. To improve the velocity of
air, the throttle valve is closed to such an extent that
there is only a small contracted passage is provided
near the end of by-pass. By this, the velocity of air,
passing through the region increases, producing the
high suction, which operates the nozzle at auxiliary
chamber and the air-fuel mixture supplied through
the holes.
There is starting and slow running device is fitted in
reservoir (Auxiliary Chamber).To vary the supply of
air to the nozzle, the set screw given is slackened
and whole assembly is taken out. By the suitable
number of rotation of screw joint, the position
ofauxiliary nozzle is set. The whole device is then
again fitted to the carburetor and tightened the screw.
Working at Normal Running
At this condition, the throttle valve is opened about
66% and as the air entering through the passage,
passes through the venturi, its velocity increases due
to smaller area consequently its pressure drops,
resulting the suction effect. The fuel is sprayed in the
venturi by main and auxiliary nozzle. As the speed of
engine increases, there by producing the greater
suction. Due to this, greater fuel being supplied by the
main nozzle. Since the compensating jet (Auxiliary
Jet) draws fuel from reservoir (Auxiliary Chamber),
which is subjected to atmospheric pressure, through
the air, the quantity of fuel supplied by it to the venturi
does not change to an appreciable extent. This has
the effect of supplying a weaker solution than if only
one jet were provide in which case, the air-fuel
mixture supplied at high speed will be richer then
desired.
Thus the compensating jet enables the air-fuel
mixture of the desirable strength to be supplied. In
fact with correctly proportioned design of various
parts of this carburetor, the fuel supplied by the main
and compensating nozzle can be made to bear
almost a constant ratio to the air supplied.

PSC Books for MECHANICAL ENGINEERING

GATE Books for MECHANICAL ENGINEERING
Sl.NO.
SUBJECT
AUTHOR
1.
ENGINEERING Thermodynamics
P.K. Nag
2.
I.C. Engine
V. Ganeshan
3.
Gas Turbine and Propulsive Systems
Rodger and Kohen
4.
Fluid Mechanics
R.K Banshal
5.
Compressible Flow
Anderson and Yahya
6.
Heat and Mass Transfer
D.S Kumar
7.
Refrigeration and Air Conditioning
C.P Arora
8.
Fluid Machinery
S.S Ratan
9.
Theory of Machines
S.S Ratan
10.
Mechanical Vibration
Grover, V.P Singh
11.
Machine Design
Khurni & V.B Singh
12.
Material Science
I.P Singh
13.
Production Engg.
P.N Rao & Sharma
14.
Industrial Engg.
Savita Sharma
15.
Operations Research
G.H Ryder
16.
Strength of Materials
Timoshenko B.C. Punamia

Recent Trends in Automobile Engineering

Since the invention of the internal combustion engine, automotive engineers, speed junkies and racecar designers have been searching for ways to boost its power. One way to add power is to build a bigger engine. But bigger engines, which weigh more and cost more to build and maintain, are not always better. Another way to add power is to make a normal-sized engine more efficient. Adding either a turbocharger or a supercharger is a great way to achieve forced air induction. Both superchargers and turbochargers pressurize the air intake to above atmospheric pressure. The difference between the two devices is their source of energy. Turbocharger is an exhaust gas driven compressor used in internal-combustion engines to increase the power output of the engine by increasing the mass of oxygen entering the engine. A key advantage of turbochargers is that they offer a considerable increase in engine power with only a slight increase in weight.Unlike turbochargers, which use the exhaust gases created by combustion to power the compressor, superchargers draw their power directly from the crankshaft. Superchargers increase intake by compressing air above atmospheric pressure, without creating a vacuum. This forces more air into the engine, providing a "boost." With the additional air in the boost, more fuel can be added to the charge, and the power of the engine is increased. There are three types of superchargers: roots, centrifugal, twin-screw. The main difference among them is how they move air to the intake manifold of the engine. Roots and twin-screw superchargers use different types of meshing lobes, and a centrifugal supercharger uses an impeller, which draws air in. Although all of these designs provide a boost, they differ considerably in their efficiency and sizes. The biggest advantage of having a supercharger is the increased horsepower. 

Pics Of Mechanical Machines

Best Books For Mechanical Engineering

Best Books Recommended For Mechanical Students During Their Self Study  

• Engineering Thermodynamics By 

1. P.K.Nag 
2. D.S. Kumar
3. A.Cengel Michael A. Boles
4. R.K.Rajput

• Fluid Mechanics By

1. R.K.Bansal
2. D.S.Kumar
3. F.M. White
4. Dr P.N. Modi,Dr S.M.  Seth  

• Theory Of Machines By

1. R.S. Khurmi
2. V.P. Singh
3. Rattan
4. Thomas Bevan

• Mechanics Of Solids

1. R.K. Rajput
2. R.K. Bansal
3. Sadhu Singh
4. E.P. Popov
5. Stephan H.Grandall,Nounman C.Dahl & Thomas J.Hardner

• Production Technology By

1. Ghosh & Malik
2. P.N. Rao
3. R.K. Jain
4. P.C. Sharma
5. Little
6. Raghuvanshi

Link For Better Videos Results

https://www.youtube.com/user/alok6gupta?ob=0

FM

I'll admit when I first saw the words "Dimensional Analysis," I felt my skin flush; my heart started beating faster; my mind began racing; and I scanned the exits of the room I was in. Classic fight or flight, with an emphasis on the latter.

But as I read, I realized my first reaction was silly. That said, I couldn't stop thinking that a lot of this was hand-waving. Can we legitimately summarize this discussion (or least summarize the justification) by observing that "in physics, almost everything is continuous" so arguments like this just work?

More precisely, what exactly is "length scale" or "characteristic length" supposed to represent? Is this along the lines of the length of the box everything is contained in, or is this the length of the smallest phenomenon observable/significant? What about in problems with a large container and small phenomena of global significance?

Also, why do we put a bar on the velocity scale U?

Finally, how is Reynolds number in any way well-defined? Can't I just say the scales are approximately this or that and get entirely different values?

Onto the next section, when can we legitimately make the lubrication assumption and get realistic results? I want to say for "slippery" fluids, but what does that even mean?

When we get a time estimate for the length of time needed to remove an adhering object, what assumptions are we making about the way it's pulled off? I feel like this should be clear, but wasn't really for me.

Overall, really cool stuff. I'm amazed that despite the sophistication of the equations, we can get tangible and useful numerical results.

SUNDAY, APRIL 13, 2008

Reading 4/14/2008: Lecture 7

First derivation is very cool. Energy minimization leads to the fluid cylinder instability. Makes sense, and the derivation is simple enough.

Very cool to see Bessel functions popping up, though given the type of equations and the space on which we're solving them, this doesn't seem particularly surprising, comparing to experience with Math 180.

Overall, it all makes sense to me. It's very interesting to see that what is fundamentally a stability analysis can be performed by linearizing and solving the system and then looking at solutions for which the waves grow. I'm a little unclear as to where the "asymmetric modes" part of the final paragraph comes from, but the fact that wavelengths greater than a threshold value grow to infinity actually makes sense to me.

NB: Sorry I've missed so many blog entries. If I can find time, I'm going to go back and write them, but these past two weeks have been absolutely vicious.

WEDNESDAY, APRIL 2, 2008

Reading 4/2/2008: Lecture 3 Notes

I wish I'd had more time to blog recently, but life has been a little too crazy.

At any rate, this is cool stuff. It's nice to see how the free-surface boundary conditions play out in the mathematical PDEs framework, and it's even cooler to see a fairly rigorous proof of Bernoulli's theorem. Obviously the same concepts are there, but, well I'm a mathematician, so it's better now.

Definitely cool to see the Fourier transform appear in the end, too. I'd be curious to hear about the general applicability of the FT in fluids - it's certainly a big hammer and great for making this smooth. (No pun intended.)

The series expansion strangely reminded by of perturbation theory from big quantum; I'm guessing this is a fairly standard approach, I think it's more the notation. That said, I wonder how applicable the linearized equations are and/or what are their drawbacks?

WEDNESDAY, MARCH 12, 2008

Reading 3/10/2008: Section 3.6

Late, I know, but better than never.

This stuff honestly is straightforward. Having seen complex variable before, the approach is a little weird (partial derivatives of a complex function and chain rule usage are a little suspect, but it works).

Laplace's equation is solved pretty thoroughly in a bunch of classes, so that's pretty much par for the course. It is really cool to see the stuff on p. 197 about using the real vs. complex part as the potential. Didn't know you could look at it that way.

What exactly happens physically at the interface where, mathematically, the pressure becomes negative? That was really my only major question from the chapter.

WEDNESDAY, MARCH 5, 2008

Reading 3/5/2008: Sections 3.4-3.5

Section 3.4: Very cool; we have a number that can tell is whether we make the assumption of diffusion-dominance or vorticity-dominance. Makes sense to me, though where do we get the characteristic length scale from? And why does it shrink with turbulence? Otherwise, everything is clear.

Section 3.5: The derivation of small Bernoulli is very straightforward, though the result is quite cool. For big Bernoulli, we demand that a flow is irrotational - where are some examples where this really breaks down in a big way? Also, how might one measure &phi, the velocity potential function, much less its time rate of change?

The connection with the Laplacian here makes sense given our assumptions, but is a nice touch. The dipole/etc. thing is worth discussing in class. I've never understood physicists' fascinating with dipoles, but maybe I can with a little more detail.

MONDAY, MARCH 3, 2008

Reading 3/3/2008: Sections 3.2-3.3

Section 3.2: Okay, cool. Our equations reduce with the acoustic approximation to something much more tractable. Very nice. I'm a little curious why we can assume (3.58) can only be satisfied in the two ways mentioned in the book. If I had a little more time, I would sit down and just prove this, but I wonder if there's a quick answer?

What are the real-world implications of S-waves decaying so rapidly? If the waves are only significant very, very close to the source, where do they arise/where are they important in practice?

How is the scattering effect of particles in p. 163 accounted for in fluid models?

Overall, this section seemed pleasantly simple. We get some nasty dispersion relations, but they're easy enough to use, and reduce to forms that are fairly easy to work with. Cool stuff.

Section 3.3: A section with "Theorem" in the title. Yay, math. Honestly, everything here made good sense. I wish I could see a more rigorous proof of the theorem, but for our purposes, this seems pretty good to me.

The bit at the end about vortex tubes is awesome. So THAT'S what a tornado is...

Reading 2/27/2008: Section 3.1

Woo, Fluids.

So we can immediately dispense with &mu, simplifying things quite nicely. Very cool derivation, and seemingly quite rigorous. I'm not entirely clear why we can assume &xi_n,n is zero, but I'm assuming it's because S_mm is &Phi.

The derivation of the new equation of state is very cool. It's remarkable to see that dp can be characterized completely and uniquely in terms of &rho. I'm not quite sure where the book is going with the "exact differential" comment, but I'm assuming that means something to physicists that it lacks in meaning to me.

Why do we assume viscous stresses are linearly proportional to velocities? What is the origin of this postulate? That was one of the major aspects unclear in the section. Otherwise, the derivation of Newtonian viscosities was clear enough.

And holy cow, we have Navier-Stokes! If only we could solve them generally...

I'm a little unclear what is meant by a volume force in (3.27) - is this just to emphasize that this is a force separate from the external (e.g. gravitational) force?

On p. 151 I just want to point out that the word "magma" is bloody awesome. Everyone should incorporate it into their daily speech immediately. No, seriously. I mean it.

Overall a fantastic section.

What are some things that mechanical engineers know and others don't?

That the father of computers is a mechanical engineer.
Charles Babbage (1791-1871), computer pioneer, designed the first  automatic computing engines. He invented  computers but failed to build  them

He designed something called Difference Engine which is a Mechanical Computer

A mechanical computer is built from mechanical components such as levers and gears, rather than electronic components.

A difference engine is an automatic mechanical calculator designed to tabulate polynomial functions. The name derives from the method of divided differences,  a way to interpolate or tabulate functions by using a small set of  polynomial coefficients. Most mathematical functions commonly used by  engineers, scientists and navigators, including logarithmic and trigonometric functions, can be approximated by polynomials, so a difference engine can compute many useful tables of numbers.

Artistic display of a portion of Difference Engine #1

Part of Charles Babbage's difference engine (#1), assembled after his  death by his son, Henry Prevost Babbage (1824–1918), using parts found  in Charles' laboratory

Difference Engine No. 2, built  faithfully to the original drawings, consists of 8,000 parts, weighs  five tons, and measures 11 feet long.The first complete Babbage Engine was completed in London in 2002,  153 years after it was designed

First complete model of difference Engine #2

The London Science Museum's  difference engine, the first one actually built from Babbage's design.  The design has the same precision on all columns, but when calculating  polynomials, the precision on the higher-order columns could be lower.