Arrangement of Books in a Library

A few days ago, there was an item the BBC website:

Coronavirus: Library books rearranged in size order by cleaner

The title says it all, but one has to look at the photo to appreciate the result.

During the lockdown, a team of cleaners went through the shelves and re-arranged all books in the order of their heights!

This may be shocking for regular users of the library.
But that set me thinking:

When books are arranged in topic-order (typical for a scientific/technical library, which uses a coding, e.g. the UDC), the result is an arrangement with random heights.   However, this is very convenient for people (students/teachers/readers) to find books on a particular subject, field, or topic.

However, this means that the vertical spacing between shelves is dictated by the tallest book, and hence lots of empty space is also 'stored'.  This may be considered a waste of space - a scarce resource in many places.

Suppose the whole library arranges books by height.  That means, jumbled up w.r.t. subject, etc..
But on a given shelf, there will be books of almost the same height.  That means, we can adjust the empty space above them to the minimum, and thus store more books!  The library will now need less overall space.  Or, in a given space, we can store more books.

There is another advantage of this.  Serendipity and happiness will increase.

Consider the scene: I visit a library, I go through the indices (necessary now), and find that the book on Thermodynamics that I want to access is on Shelf 23B4.  I go there, and find the book I need.  However, there is a good probability that surrounding that I find a novel that I wanted to read (say Jules Verne's Around the World in Eighty Days).  I am happier, and my life is richer.

As a result of this, engineers may look at fiction, they may also read some sociology!  You can extend this and imagine yourself in such a library.  Communication between scientists, engineers, sociologists, economists, and laypeople will improve.

Does any small library want to try this out?  I will help out.  And, the reduction in space will be nicely quantifiable!

Entropy

A few days ago, a good friend of mine (since by IITB-student days) wrote:

This morning me, my brother and niece (who are both chemical engineers) were discussing thermodynamics and in particular, entropy. 

My brother and niece were convinced that entropy is a purely theoretical, abstract, and dry concept, and need not be taught. 

I narrated our old story of ejector design in detail and how you  helped with a revised analysis covering entropy (which was not considered in the original design), and how it worked perfectly well after that.

Since you have taught entropy in your teaching of thermodynamics many times, tell me, how many of your students really understand entropy? 

He wanted me to comment.  So, here goes:

Among engineers, I believe Mechanical Engineers ("We", henceforth) live happily with entropy.  We need it to analyse and design compressors, turbines, pumps, ejectors, mixers, ... .
We develop a feel for it.

Imagine our student (and for many, professional) life without an entropy axis (and it is always the x-axis, the major axis) on  T-s,  p-s,  h-s,  and so many other diagrams!

Even the good-old-professor  B. B. Parulekar  (of Khandu Patil fame) was happy to work with entropy, even though he kept away from the mathematics involved in its derivation.

And without entropy, we will find it difficult to define Gibbs Function, and hence chemical potential.  How do we study chemical equilibrium without it?

Maybe 10% of students who study thermodynamics understand entropy fully.

To paraphrase  Francis Bacon:
Some students just taste entropy, others just swallow it, and some few chew and digest it.

But fractions are confusing.  When I started teaching (as a formal teacher at IIT Bombay), my first lectures on thermodynamics were to a group of some  42  UG students.  But there was a core group of about  20  to  25  students (and they typically sat in a  5x5  or  4x6  formation, front, centre of the classroom, even their relative positions were almost fixed).  These were the alert ones, trying to understand everything, and ready to jump at the teacher if anything went off-track or was confusing.  I soon realised that I was teaching, essentially, these students.  [The class size went from 42 to 60 to 90 to ..., but the number in the core group remained the same, more or less.]

And I think these were the students who understood entropy.  And some of them continued to flirt with it, some had it as their girlfriend (half or otherwise), some are married to it and are living happily! 

While discussing with Prof Achuthan on not-any-particular-topic (and this was common), we realised that there are perhaps three types of manipulations that we need to do.

From the simple to the not-so-simple, these are:

Numerical manipulation (NM):
Arithmetic++.  All students are good at this.  And with the advent of calculators, our effective ability at NM has improved significantly.  Traditionally, active members of the trading class were excellent at NM.  We continue to do, actually need to do, NM throughout our life.

Symbolic manipulation (SM):
Algebra++.  A large majority of students are good at this.  This begins in high school with algebra, then trigonometry and calculus, then calculus++.  A large number of science and engineering graduates are good at SM.  And, the advent of software for symbolic manipulation has improved our effective ability in SM.  We keep on doing some sort of SM later in life.  Scientists and engineers do it continuously throughout their professional life.

Concept manipulation (CM):
This is the ability to handle different concepts, and then fields, together.  We have to do it, as students, to absorb high-level concepts in mathematics, science, and engineering.  Later, only perhaps researchers and professors do it!

Remember our school/college/maybe even university exams?

Questions were usually chapter-wise.  One chapter - one question (if at all).  In geometry, each question was (a) some theorem to prove, and (b) a rider in which that theorem was the main idea needed.  This requires a low level of CM, if at all.

But if you are confronted with a problem which requires material from two or more chapters from the textbook of a given subject, then you have to do a bit of conceptual manipulation, and this increases the degree of difficulty.  Real-life situations need ideas and concepts from different fields.  For example, detailed modelling of an electrical machine needs that we use electromagnetism, fluid mechanics, thermodynamics, heat transfer, as well as solid mechanics (to determine thermal stresses, and structural deformation).  This needs a reasonable amount of concept manipulation.

Even in a given subject, we need to combine and extend concepts (terms, definitions) to create newer concepts.

In thermodynamics, the major concepts are energy, temperature, and entropy.  Of these, energy straddles many (almost all) branches of physics, and is not very difficult to grasp.  Temperature is a basic thermodynamic idea, and requires some concept manipulation, using the zeroth law of thermodynamics. 

The idea of entropy involves a significant amount of concept manipulation.  That is because it is (almost) the final extract of a derivation beginning with the second law of thermodynamics.

Just consider (this will be familiar to those who are still friends with entropy):  We start with
the second law of thermodynamics - the Kelvin-Planck statement.  Then we take a very scenic tour through heat engines, a definition of efficiency, thermal reservoirs, 2T-heat-engines, a hierarchy of temperature levels, a definition of 'higher' and 'lower' temperatures, (possibly a detour to refrigerators/heat-pumps, and their performance parameters,) the idea of reversibility and reversible processes, the Carnot theorem, the Carnot engine, thermodynamic temperature scales, thermodynamic Kelvin scale, (the Carnot cycle, and proof of equivalence of thermodynamic-Kelvin and ideal-gas-Kelvin scales,) the Clausius inequality and its proof; and then using the equality part of Clausius inequality we arrive at the definition of entropy.  This requires a significant amount of algebraic as well as conceptual manipulation.

Another fact is that the ideas of energy ("the ability to do work") and temperature ("degree of hotness") are introduced in school, with very simplistic methods.  One of my (self-assigned) tasks in IIT Bombay is to make our students get rid of (unlearn) many such ideas from their school days.

Unfortunately, for entropy, there is no 'short-and-sweet' definition (however incorrect).  Hence, the belief that entropy is a dry, purely theoretical, and abstract concept! 

We should also understand that many of the terms we use are short-forms (terminology).  In thermodynamics, we use the word 'system' as a short form for 'a region of space, with well-defined boundaries, in which we are interested'.  'Property (of a system)' is a short form for 'relevant measurable characteristic (of a system)'.  Imagine our frustration if we do not use such terminology during our study of thermodynamics (or for that matter, any science).

Unfortunately, for 'entropy', there is no 'expanded form'.  It is an extraction of all that the second law of thermodynamics stands for.

That is what makes an appreciation of entropy difficult.  I mentioned that maybe 10% of my students understand it.  In professional life, even a smaller number need to use it.  This small-usage fraction is true not just for entropy, it is true for a large number of topics and concepts, sometimes whole subjects!  Any reader of this blog with an engineering and/or science background will appreciate this.

So, perhaps, the reasoning of the brother-and-niece was this:  we did not use entropy in our professional life (and maybe we did not understand it as students), so it need not be taught.

Imagine implementing the same logic on X (replace X by your favourite concept) .  If one takes this to its logical end, we will have to close down, maybe, our whole education system!

IIT Bombay Campus - Then (1972) and Now (2019)

2019 12 20

[Please click on the photographs to see the full version.]

I have sourced the 'Then (1972)' photos as screenshots of the movie Jawani Diwani, which was, in part, shot on campus.  Since these are screen grabs, the resolution is not that good.
The 'Now (2019)' are shot by yours truly.

So, here we go:

The first location is the East-End of the Corridor:

The second location is ME Lawns, with the Main Building in the background:

The third location is ME Lawns, with the ME Building in the background:

The next three shots are from near the Lecture Theatre.

Fifth:  LT Foyer, seen from the MB side: 

Sixth:  MB Annexe as seen from near the LT:

Seventh, looking North from near the Breznev tree (yes, it is still there):

Finally there is a shot from in front of the Convo Hall towards the Main Building:

Some shamiyana-work was going on today.  Preparations for the Alumni Day, I suppose.

But the Main Building looks very the same:

 And so does its annex, where we had out drawing halls:

Finally, here is a panoramic picture from the West footpath of the Main Road.

The road is our Main Road.  Main Building is towards the left, Main Gate is towards the right.  The left building is the School of Management and IRCC, the centre one is the Computer Centre, and the right one is the Kanwal Rekhi Building.  The 'ghosts' in the picture are people, compressed by the camera software while processing the panorama.

The Deserted Hostel 8. IIT Bombay Campus.

2019 12 19.

Hostel 8 is unlivable.  All students have left (and not just on vacation).  Today morning when I visited, a lonely watchman was on guard.  No one in the corridors, no one in the rooms, no one in the mess.

Hostel 8 is abandoned and will be demolished.  Another version of Hostel 8 will be built in its place.

I have never seen a hostel so deserted.  This reminded me of the poem "The Deserted Village", by Oliver Goldsmith.

I am told the same fate awaits Hostel 4 and Hostel 7.

Some More Pictures of IIT Bombay Academic Area

2019-12-18
[Added one picture on 2019-12-20.]

(Please click on the photographs to see the full version.)

The Civil Engineering Department Building:

The Lecture Theatre and the LT Lawn:
(The LT is now called P C Saxena Auditorium, PCSA.)

The Central Walkway, from Main Building to IDC and beyond:

Remember the open space and gap in the corridor between Maths and Library?
There was a tree there, which died.
We now have a gazebo at that place, with a sculpture "Hands Reaching Out":

Here are the details.

And here is a bottom-up-view:

Coming soon:  Some photos of Hostel 8.

Some Pictures of IIT Bombay Academic Area (Nostalgia, Then-and-Now)

2019-12-17.

(Please click on the photographs to see the full version.)

While going through my old collection, I came across a 1973 photograph of the Mechanical Engineering Department Building:

I walked up the Main Building on 13-Dec-2019 to try the 'now' version of the same photograph.  Unfortunately, we now have so much of greenery, fortunately, that I could see hardly any part of the ME Building.  I tried two different angles:

I think the only common thing in the two photographs is the big palm tree.

Many of us do not realise how green the IIT Bombay campus has become, over the years!

BEST Route 602, Mumbai

Today, I rode BEST route 602 from Hiranandani Bus Station, Powai, to IIT Main Gate.

For Rs 5 I can skip a 1.5 km walk.  

However, I do not save any time - the bus takes a very circuitous route.

Today, sitting up front, I noticed two old things which still remain unchanged on BEST buses:

• Conductor's bell (top left in the picture above).
• The hand-operated horn (seen near the driver).

I think there are advantages in using the manual bell and horn.

• The conductor/driver will not use the bell/horn unnecessarily - operating them requires effort!
• In the cacophony-on-road in Mumbai, the sound made by the bell and horn is soothing.  It almost sounds like music!