YEAR 1 | ISSUE 3 | JULY, 2012
It is well known that Physics and Mathematics are the backbone of engineering. One has to have a clear-cut understanding of these subjects while applying them in engineering. However, a blind application of Physics will create a lot of trouble and confusion. This can be illustrated by taking a simple problem of “Flow of current”. As per the definition, the current is the rate of flow of charge. However, if you blindly apply this definition while designing the power line you may land in trouble. Let us assume that you are asked to design a power line of 100km length with a bulb of 10 ohms as a load using Copper cable using a source. Now you proceed to calculate the time taken by the charge to reach the destination. If you take the standard values of the parameters of copper cable of 5mm radius and calculate the time for the electrons to reach the bulb you will get a figure of roughly 445 years. Naturally, you will try to check and recheck the calculations and you will find the same result. Then what happened? In fact it is not the Drift velocity of electrons but it is the Electromagnetic Propagation velocity which travels with the velocity of light. But again, if we use free space value of velocity of light you will have some practical difficulties because the propagation velocity in typical coaxial cable with copper based central conductor is about 66% of the velocity of light. Hence the time will be roughly 505µs.
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In order to design the new system apart from the exposure to established engineering truths and best practices coupled with art and technology should be taken into account and for this one has to master such concepts which will take time and patience. A modern era of science and technology with multiple planes of knowledge is required for system development of any kind. For example, to design a computer chip you must know materials like Silicon, layout (lithography), A/D(sigma-delta), real-time operating systems etc. Also don’t forget to introduce art and beauty in designing the system. As an example Eiffel Tower was designed with a lot of structural calculations, mathematical computation and other engineering related parameters. However, the designers saw to it that it should have an aesthetic value also. Second example is I-phone which is very small and compact and has been designed in such a way that apart from looking beautiful it is so much users friendly that the supplier provided only page of operating manual. If there are many designing options, don’t forget the Occam’s razor which says that the simpler of two competing theories making exactly the same predictions is better.
Engineers also sometimes suffer with partial credit mentality and ignoring the team spirit. Tacoma Narows Bridge that collapsed on November 7, 1940 as the leader did not consider the natural frequency at which resonance occurs if same frequency is impressed upon. That’s what happened when wind speed was 60 miles per The problem of an engineer does not stop here, who is going to design a nationwide network which is much bigger than 100km with hour on that fateful day. It was known as the death of civil engineering at that time. using the wavelength of 6000km (50Hz) and the transmission line parameters like distributed elements which will take more time to Similar thing happened with Hindenburg (1937) disaster. Now charge. finally the engineers should not ignore ethical problems . It is now known that the Challenger Disaster in 1986 was due to failure of a In designing a complete power grid, the practical aspects such as small component O-ring seal which was not tested at a temperature losses, effective consumer load, load profiles, failure and reliability below 4 degree Celsius and the temperature in Florida was -8 analysis and cost optimization are also to be considered. degree Celsius and this fact was known to the engineer who Moreover, no such thing as perfect electronic capacitors, frictionless designed it. surfaces, noiseless systems are available. In a nutshell, the real Prof. (Dr.) K. N. Tripathi world is quite complicated. So, the heart of any engineering is Advisor to Chancellor, Galgotias University understanding reality through theorizing and experimentation which is naturally a physicists’ job and finding applications and ingenuity to circumvent implementation problems will be engineers’ job.
The world does not pay for what a person knows. But it pays for what a person does with what he knows. Laurence Lee