MECHANICAL CALCULATOR is awesome......

Witness the jaw-dropping ingenuity of this fascinating hand-held mechanical calculating machine.

Ecowatch - Environmental Awareness

Ecowatch - Environmental Awareness
Resource Persons : Sri. S Nandakumar, Sri. Suresh Heblikhar, Dr. R Lakshminarayana, Sri. Ullas Kumar and Sri Prakash Murthy
Sl.No	Topic	Materials
1	Urban ecosystem management & eco-cities	Click here
2	Health, rural water supply & sanitation	Click here
3	Climate Change and Global Warming	Click here
4	Solid waste management & city sanitation policy	Click here
5	An overview of hazardous waste management	Click here
6	Need for effluent treatment and legal aspects	Click here
7	QUICK ENER-G SOLUCTIONS	Click here
8	Home Solar's	Click here
9	Biofuels	Click here

EDUSAT Softskills Training

                            

                           EDUSAT Softskills Training

EduSat:  Soft Skills Training Topics
Resource Person: Arun John Mathias, JV Global
Sl.No	Topic	Hours	Date	Materials
1	Introduction to soft skills	10:00 AM to 11:00 AM	23-Feb-13	Click here
2	Verbal Communication		23-Mar-13	Click here
3	Non-verbal communication		30-Mar-13	Click here
4	Time management & Motivation		6-Apr-13	Click here
5	Teamwork & Leadership		20-Apr-13	Click here
6	Business communication & Etiquette		27-Apr-13	Click here
7	Resume and cover letter writing		4-May-13	Click here
8	Group discussions		10-May-13	Click here
9	Interview skills		18-May-13	Click here

GRAVITATIONAL WAVES: our scientists finally did it....discovered a whole new room for new discoveries....

GRAVITATIONAL WAVES: our scientists finally did it.....discovered a whole new room for new research and discoveries.......to explore.

In physics, gravitational waves are ripples in the curvature of space time which propagate as waves, travelling outward from the source. Predicted in 1916 by Albert Einstein on the basis of his theory of general relativity, gravitational waves transport energy as gravitational radiation. 

The existence of gravitational waves is a possible consequence of the Lorentz invariance of general relativity since it brings the concept of a limiting speed of propagation of the physical interactions with it. By contrast, gravitational waves cannot exist in the Newtonian theory of gravitation, which postulates that physical interactions propagate at infinite speed.

Before the direct detection of gravitational waves, there was indirect evidence for their existence. For example, measurements of the Hulse–Taylor binary system suggest that gravitational waves are more than a hypothetical concept. 

Potential sources of detectable gravitational waves include binary star systems composed of white dwarfs, neutron stars, and black holes. Various gravitational-wave detectors are under construction or in operation, such as Advanced LIGO which began observations in September 2015.

On 11th February 2016, the Advanced LIGO team announced that they had directly detected gravitational waves from a pair of black holes merging

In general terms, gravitational waves are radiated by objects whose motion involves acceleration, provided that the motion is not perfectly spherically symmetric (like an expanding or contracting sphere) or cylindrical symmetric (like a spinning disk or sphere). 

A simple example of this principle is a spinning dumbbell. If the dumbbell spins like a wheel on an axle, it will not radiate gravitational waves; if it tumbles end over end, as in the case of two planets orbiting each other, it will radiate gravitational waves. 

The heavier the dumbbell, and the faster it tumbles, the greater is the gravitational radiation it will give off. In an extreme case, such as when the two weights of the dumbbell are massive stars like neutron stars or black holes, orbiting each other quickly, then significant amounts of gravitational radiation would be given off.

                                    

                             A schematic diagram of a laser interferometer

Some more detailed examples:

• Two objects orbiting each other in a quasi-Keplerian planar orbit (basically, as a planet would orbit the Sun) will radiate.
• A spinning non-axisymmetric planetoid — say with a large bump or dimple on the equator — will radiate.
• A supernova will radiate except in the unlikely event that the explosion is perfectly symmetric.
• An isolated non-spinning solid object moving at a constant velocity will not radiate. This can be regarded as a consequence of the principle of conservation of linear momentum.
• A spinning disk will not radiate. This can be regarded as a consequence of the principle of conservation of angular momentum. However, it will show gravitomagnetic effects.
• A spherically pulsating spherical star (non-zero monopole moment or mass, but zero quadrupole moment) will not radiate, in agreement with Birkhoff's theorem.

More technically, the third time derivative of the quadrupole moment of an isolated system's stress–energy tensor must be nonzero in order for it to emit gravitational radiation. 

This is analogous to the changing dipole moment of charge or current necessary for electromagnetic radiation

Power radiated by orbiting bodies

Two stars of dissimilar mass are in circular orbits. Each revolves about their common center of mass(denoted by the small red cross) in a circle with the larger mass having the smaller orbit.

Two stars of similar mass are in circular orbits about their center of mass

Two stars of similar mass are in highly elliptical orbits about their center of mass

Gravitational waves carry energy away from their sources and, in the case of orbiting bodies, this is associated with an inspiral or decrease in orbit.

 Imagine for example a simple system of two masses — such as the Earth-Sun system — moving slowly compared to the speed of light in circular orbits. 

Assume that these two masses orbit each other in a circular orbit in the x–y plane. To a good approximation, the masses follow simple Keplerian orbits. 

However, such an orbit represents a changing quadrupole moment. That is, the system will give off gravitational waves.

Suppose that the two masses are  and , and they are separated by a distance . The power given off (radiated) by this system is:

 

where G is the gravitational constant, c is the speed of light in vacuum and where the negative sign means that power is being given off by the system, rather than received. 

For a system like the Sun and Earth,  is about 1.5×10¹¹ m and  and  are about 2×10³⁰ and 6×10²⁴ kg respectively. In this case, the power is about 200 watts.

 This is truly tiny compared to the total electromagnetic radiation given off by the Sun (roughly 3.86×10²⁶ watts).

In theory, the loss of energy through gravitational radiation could eventually drop the Earth into the Sun. However, the total energy of the Earth orbiting the Sun (kinetic energy +gravitational potential energy) is about 1.14×10³⁶ joules of which only 200 joules per second is lost through gravitational radiation, leading to a decay in the orbit by about 1×10⁻¹⁵ meters per day or roughly the diameter of a proton. 

At this rate, it would take the Earth approximately 1×10¹³ times more than the current age of the Universe to spiral onto the Sun. 

This estimate overlooks the decrease in r over time, but the majority of the time the bodies are far apart and only radiating slowly, so the difference is unimportant in this example.

A more dramatic example of radiated gravitational energy is represented by two solar mass (M_☉) neutron stars orbiting at a distance from each other of 1.89×10⁸ m (only 0.63 light-seconds apart). [The Sun is 8 light minutes from the Earth.] Plugging their masses into the above equation shows that the gravitational radiation from them would be 1.38×10²⁸ watts, which is about 100 times more than the Sun's electromagnetic radiation.

for details go to:

• Gravitational wave background
• Gravitational field
• Gravitomagnetism
• Graviton
• Gravitational wave astronomy
• Hawking radiation, for gravitationally induced electromagnetic radiation from black holes
• HM Cancri
• LIGO, Virgo interferometer, GEO600, KAGRA, and TAMA 300 — Ground-based gravitational-wave detectors
• Linearised Einstein field equations
• LISA, DECIGO and BBO — Proposed space-based detectors
• Peres metric
• pp-wave spacetime, for an important class of exact solutions modelling gravitational radiation
• PSR B1913+16, the first binary pulsar to be discovered and the first experimental evidence for the existence of gravitational waves.
• Spin-flip, a consequence of gravitational wave emission from binary supermassive black holes
• Sticky bead argument, for a physical way to see that gravitational radiation should carry energy
• Tidal force

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THANK YOU FOR VISITING...........STAY EXPLORING.....

INSPIRATIONAL QUOTES ON ETHICS....

Without ethics, everything happens as if we were all five billion passengers on a big machinery and nobody is driving the machinery . and it's going faster and faster, but we don't know where.-JACQUES COUSTEAU

because you're able to do it and because you have the right to do it doesn't mean its right to do it -LAURA SCHLESSINGER

a man without ethics is a wild beast loosed upon this world-MANLY HALL

the concern for man and his destiny must always be the chief interest of all technical effort. never forget it among your diagrams and equations. -ALBERT EINSTIEN

cowardice asks the question, "is it safe" , Expediency asks the question,"is it politic?", vanity asks the question,"is it popular", but , conscience asks"is it right", and there comes a time when one must take a position that is neither safe,nor politic, nor popular but one must take it because one's conscience tells one that it is right.-MARTIN LUTHER KING,JR

to educate a man in mind and not in morals is to educate a menace to society. - THEODORE ROOSEVELT

politics which revolves around benefit is savagery

-SAID NURSI

the true test of civilization is , not the census, nor the size of the cities, nor the crops, but the kind of man that the country turns out.  -RALPH W.EMERSON

the measure of a man's character is what he would do if henew he never would be found out    -THOMAS B.  kMACAULAY

WHAT ARE FUEL CELLS.....

fuels like methane are commonly burned to provide thermal energy at high temperatures for use in heat engines. however a comparison of the reversible works obtained in the last two examples reveals that the exergy of the reactants(818 MJ/kmol CH4) decreases by 288 MJ/kmol as a result of the irreversible adiabatic combustion process alone. that is , the exergy of the hot combustion gases at the end of the adiabatic combustion process is 818-288=530 MJ/kmol methane. in other words, the work potential of the hot combustion gases is about 65 percent of the wok potential of the reactants. it seems that when methane is burned, 355 of the work potential is lost before we even start using the thermal energy.

thus, the second law of thermodynamics suggests that there should he a better way of converting the chemical energy to work . the better way is ,of course, the less irreversible way, the best being the reversible case.

in chemical reactions, the irreversibility  is due to uncontrolled electron exchange between the reacting components. the electron exchange can be controlled by replacing the combustion chamber by electrolytic cells.like car batteries. (this is analogous to replacing unrestrained expansion of a gas in mechanical system by restrained expansion) 

in the electrolytic cells, the electrons are exchanged through conductor wires connected to a load, and the chemical energy is directly converted to electric energy. 
the energy conversions devices that work on this principle are called FUEL CELLS.

fuel cells are not heat engines, and thus their efficiencies are not limited by the carnot efficiency . they convert chemical energy to electrical energy essentially in an isothermal manner.
a fuel cell functions like a battery,except that it produces its own electricity by combining a fuel with oxygen in a cell electro chemically without combustion. and discards the waste heat. a fuel cell consists of two electrodes separated by an electrolyte such as a solid oxide, phosphoric acid, or molten carbonate. the electric power generated by a single fuel cell is usually too small to be of any practical use therefore  fuel cells are usually stacked in practical applications. this molecularity gives the fuel cells considerable flexibility in application:the same design can be used to generate a small amount of power for a remote switching station of a large amount of power to supply electricity to entire town. therefore . fuel cells are termed the "microchip of the energy industry"


the operation of a hydrogen -oxygen fuel cell

hydrogen is ionized at the surface of the anode,and hydrogen ions flow through the electrolyte to the cathode. there is a potential difference between the anode and  the cathode, and free electrons flow from the anode to the cathode through an external circuit (such as a motor and a generator). hydrogen ions combine with oxygen and the free electrons at the surface of the cathode, forming water. therefore , the fuel cell operates like an electrolysis system working in reverse.in steady operation ,hydrogen and oxygen continuously enter the fuel cell as reactants and water leaves as the product. therefore ,the exhaust of the fuel cell is drinkable quality water.


this was the brief overview and there is a lot on this topic...and also a major future hope .....of energy sectors......of the world



for more information ref: Yunus A Cenegal , Michael A Boles THERMODYNAMICS....8TH EDITION.




i know it was a bit heavy to take it a once ......but am sure here after u aren't new to this topic..


any kind of queries and suggestions are most welcomed ...



thank you for visiting............

PRACTICAL ENGINEERING PROBLEMS SOLVING TECHNIQUE

hi friends,

as a professional engineer i know what difficulties we engineers face during our academics and also during training in industries....out of all those one of the most prominent and dominant is to SOLVE ENGINEERING NUMERICAL PROBLEMS...though it is the most easiest task an engineer could ever do in his life the image of its non existing difficulty in solving it persists in the mind set which intern stops one even to attend it .

yesterday i was reading a book on ADVANCED THERMODYNAMICS by Yunus A. cenegal,Michael A.Boles one of the greatest book i have ever read.....

i came over a topic where the author as well by knowing the students problem has written a wonderful article in the book...so i thought of sharing this precious article with you guys.....
sentences are not exactly same as it is in the book rather below written is my understanding of what i have read......

the first step in learning any science is to grasp the fundamentals and to gain a sound knowledge of it. the next step is to master the fundamentals by testing this knowledge. this is done  by solving significant real world problems. solving such problems, especially complicated ones,requires a systematic approach . by using a step by step approach, an engineer can reduce the solution of a complicated problem into the solution of a series of simple problems. when you are solving a problem , we recommend that you use the following steps zealously as applicable. this will help you avoid some of the common pitfalls associated with problem solving.

• PROBLEM STATEMENT

before solving the problem at least we need to know what actually we need to solve and what information do actually we have before trying to solve it as our tools to solve it .hence it becomes necessary to note down all given data in your own words and visualize the problem and make a clear pitcher of what is need to be solved

• DIAGRAMMATIC  REPRESENTATION

draw the sketch according to your visualizations made in the previous step for all physical and non physical systems involved also it would be great if you list  out all the relevant data on the fig .

you need not worry about the rules to draw those fig rather it should be clearly understood by any one and you as well without any confusion.mainly try to indicate the energy interactions involved in the system, system -surrounding, without the system. also take care of those properties that remain constant during the process as well which is many times the most important step...for many problems.

• TAKE CARE OF ALL THE RELATED ASSUMPTIONS 

state any assumptions and approximations made to simplify the problem to make it possible to obtain a solution. justify the questionable assumptions. if sufficient data is missing try to assume it with some logic or from your previous experience e.g., in the absence of specific data for atmospheric pressure,it can be taken  to be 1 atm. however, it should be noted in the analysis that the atmospheric pressure decreases with increasing elevation.as ,it drops to 0.83 atm in dever(elevation 1610m)

• TAKE USE OF ALL RELATED PHYSICAL LAWS AND UNIVERSAL PRINCIPLES

apply all the relevant basic physical laws and principles like say ..conservation of mass, and reduce them to their simplest form by utilizing the assumptions made. however, the region to which a physical lat is applied must be clearly identified first. for example, the increase in speed of water flowing through a nozzle is analyzed by applying conservation of mass between the inlet and outlet of the nozzle.

• UNKNOWNS AND SUBSTITUTIONS

find the unknown properties at known states necessary to solve the problem from property relations of tables.substitute the known quantities into the simplified relations and perform the calculations to determine the unknowns. pay particular attention to the units and unit cancellations, and remember that a dimensional quantity without a unit is meaningless. also, don't give a false implication of high precision by copying all the digits from the screen of the calculator....come on man you are not a junior school guy still...use your head and round the results to an ppropriate number of significant digits.

• ANALYSIS AND REMEMBERING WHAT YOU LEARNT

check to make sure that the results obtained are reasonable and intuitive, and verify the validity of the questionable assumption. repeat the calculations that resulted in unreasonable values .like say ... insulating a water heater that uses 3000 rupees of natural gas a year can't be savings.....

as while solving problem you might have obviously encountered so many situations where you were stuck and those are now the areas which you must practice more to over come it....you know when you face those challenges u ll realize that they were damn easy and what u were afraid of facing it and avoiding it was meaningless.....

at the end a small suggestion ...

keep in mind that the solutions you present to your instructors, and any engineering analysis presented to pthers, is a form of communication. therefore neatness, organization, completeness and visual appearance are pf utmost important for maximum effectiveness. 

well...these steps are just a piece of guide for those who really are afraid of solving engineering problems....however you can just read carefully these steps and practice consistently and develop your intelligence every problem u solve....after attaining certain level of perfection you can find out your own way of solving problems....than difficulty level of the problem is just an another word...