Sunday, December 24, 2017

December 24, 2017 Sunday

Bedtime Story 


Automatic Controls in Kitab al-Hiyal 


Very modestly, the book - Kitab Al-Hiyal or the Book of Ingenious Devices begins taking the works of Greek civilization as the starting point.

It was not exactly a serious book of engineering but more of an amusement amateur type perhaps similar to my bedtime stories though I cannot be hundred percent sure unless I personally read the book page to page.

Around one hundred mechanical devices have been described in this book including several devices with automatic controls.

When I describe some of the instruments below you might not find them impressive if you chose to ignore or suppress the fact that we are talking about 850 AD, almost one thousand years before the beginning of Industrial Revolution in Europe.

Moreover, whatever else the three brothers may have borrowed from the works of Greeks, the concept of automatic controls was totally an avant-garde step of their own.

When I go through the kind of systems they had devised I as an ophthalmologist am quite taken aback because I find the ideas very impressive.
  
It may be partly due to my lack of knowledge of mechanical engineering but I suspect the ideas would be given due respect even by those who are in that field.

Most of the machines that the Banu Musa brothers had described were operated purely by elegant and ingenious combinatory use of hydraulics (application of fluid power), pneumatics (pressurized air) and aerostatics (non-moving fluid or air).

For the first time in a written text was found the description of “in-line” conical valve that would control the flow of two different kinds of fluids such as wine and water.

Besides conical valve, they had also described in their inventions plug valve, float valve (such as the ballcock found in our flush toilets) and tap valve that is all around us.

The other novel mechanism that was found in their devices was the fail-safe system.

A fail-safe system is essentially any mechanism that will not endanger life or property if the machine as a whole fails.

For instance, they describe a machine that allows one to draw out small quantities of liquid from time to time, but withdrawing a larger amount of that assigned would not be permissible by the machine.

One of the crucial inventions that has a direct bearing on our story was their description of the crank that appear in several of their devices.

Many of you may not know what a crank is since most modern apes are neither mechanical engineers nor desire to get their hands dirty working with machine tools.

A crank is a device that converts a circular motion into a reciprocating motion.

Now you may wonder what a reciprocating motion is.

Well, a reciprocating motion is a repetitive either up-and-down or back-and-forth linear motion.

Stay tuned to the voice of an average story storytelling chimpanzee or login at http://panarrans.blogspot.com
                              
Good night mon ami and my fellow cousin ape.
                           
  
                

             












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Another great educator and a teacher that I am aware of is Professor Subhashish Chattopadhyay in Bangalore, India.

While I narrate stories, Professor Subhashish an electronic engineer and a former professor at BARC, does and teaches real mathematics and physics.

He started the participation of Indian students at the International Physics Olympiad.

Do visit him here:


All his books can be downloaded for free through this link:


For edutainment and English education of your children, I recommend this large collection of Halloween Songs for Kids:


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