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The Spring 2016 Semester

May 10th Marked the end of my second semester at Purdue. To say the least, it was eventful. But that’s no excuse to not find time for blogging. But here’s the round-up of everything that happened this semester.
I took two courses. The first one was ECE606- Solid State Devices. This is a course that deals with transistor physics. I took it as a refresher course on MOS and BJTs, mostly to prepare for my Qualifying Exam coming up on August. To sum this course up in three words – too much information! We had to cover very elementary Schrodinger’s equations, PN Junction physics, BJTs, MOSFETs, and non idealities associated with the devices. As a result, even though we had to go through a lot of concepts, both old and new, I retained very little. The other course we took was ECE618 – Numerical Electromagnetics. This was more relevant to my field – Fields and Optics. We learned the fundamentals of three types of optical simulations: the finite difference time domain (FDTD) method, the Finite Elements Method (FEM), and the Method of Moments (MOM). I had some experience with FDTD and FEM, but worked mostly with CAD software, where I mostly had to draw a shape and plug in some values and get the software to do my dirty work for me. But this time, we had to come up with our codes from scratch. The problems were tough, but with the help of my amazing teammates, we pulled through.
ECE60600 : A
ECE61800 : A+
I also received the hard copy of my Masters Degree from NUS, which kind of marks the end of the Singapore arc of my story.
I am working on quite a few projects now. They are mostly fabrication based. I’ll update more on them once I figure out how much exactly I can disclose about our research without getting into trouble.
My plan for my first PhD year was to get trained on every type of fabrication equipment that I would possibly have to use during my PhD. I wanted to do this because during my M. Eng. degree in NUS, the labs were not centrally owned, so every time I needed to use a new machine, I had to  go through a spiderweb of red-tape, and had to depend a lot of different people to get my processes done. While that helped develop my amazing(!) people skills, I decided that while I am okay with getting help from other people, I am not going to depend on someone.
Here’s the list of equipment I trained on:
Deposition: Leybold E-beam Evaporator.
Etching: The Panasonic Etcher. This is for deep reactive ion etching.
Imaging: Scanning Electron Microscope, Optical Microscope, Atomic Force Microscope, Alpha Step- Surface Profiler,  Bruker Optical Surface Profilometer.
Pattering: Electron Beam Lithography, the Mask Aligner System.
Characterization: Surface Profiler and AFM, optical Profilometer.
I thought I was done. But there’s still a lot of characterization equipment I need to train on.
Activities and Clubs:
I joined more clubs than I can keep track of this time. Let me give it a shot.
  1. Lafayette Toastmasters Club: This is to improve my public speaking skills.
  2. SPIE and OSA: The International Society for Optics and Photonics, and the Optical Society of AmericaThese two were a must, owing to the fact that I am specialising in optics.
  3. NSAC: The Nanotechnology Student Advisory Council is an organization of students in Purdue with an interest in Nanotechnology.
  4. HKN: The Eta Kappa Nu honour society. I joined this to meet more people outside of the lab. The recruitment process was intense.  Activities included volunteering and outreach work, attending industry talks, getting signatures from professors and active members, to selling coffee. I started off pretty late in the semester, and had only two weeks to finish everything. But all’s well that ends well. I got in.
  5. The Boilerout Volunteering Program. This is a club that organizes activities ranging from ushering in theaters, to collecting cans for Food Finders Food Bank. I joined this club mostly as a means to meet new people. Unfortunately, I haven’t really kept in touch with the people I worked with.
  6. BDSA and PUTS: The Bangladeshi Student’s Association (BDSA), and the Purdue University Tagore Society (PUTS) organized an event together to celebrate the International Mother Language Day. One of my goals on my bucket list was to perform in front of an audience, and I grabbed the opportunity. It was an awesome day.
  7. The Discovery Park Ambassador Program: I’ll write about it in another post.
  8. ECEGSA. The Electrical and Computer Engineering Graduate Student Organization is a club that is in  charge of all things that add a little fun to PhD life. I enlisted myself in the organizing committee as the Academic Director.
That pretty much wraps up this semester. With most of my courses done, I am looking forward to doing some interesting research now.

Newton’s Three Laws of Motion – A fun exercise

Let me start with an update on my PhD status. Obvious from the frequency of my blog posts, I have been extremely busy with my projects and coursework. But I am glad to say that, thanks to group mates I can trust and talented lab partners I can rely on when I’m in trouble, things could not have been more productive. And honestly, I don’t mind being under a lot of pressure as long as I am being productive.
Okay, now for the topic of this post. I have been wanting for a long time to write about something that’s very basic in physics – Newton’s Laws.
Before I go into detail, here’s a simple question you can ask your friends. And try to answer it as fast as possible, like, in under ten seconds. Come on, you are a smart guy! You shouldn’t take any more time than that.
While you are asking the question, make sure you contract your arm, and make a throwing motion, providing a visual aid for the innocent victim. If you are lucky, you’ll probably make them give you a wrong answer.
It seems like an easy enough question, but you would be surprised how many get this wrong. Of course, the question lacks a lot of detail. Where in space is the object? How far are the nearest bodies that might exert a force on the object?
The object is not going to slow down. Everyone gets this bit right. There’s no air resistance. So nothing slows the ball down. [Unless your time scale is over millennia and the ball loses its momentum bumping into tiny space particles floating around].
Now, why does the ball not speed up? You did exert a force on it that caused it to accelerate, and as I have established before, there’s nothing there to slow it down, right?
Well, it did accelerate as long as your hand was pushing it forward. But as soon as the ball left your hand, it did not have any force pushing on it anymore. So, it would move in a straight line in a constant speed.
But what about the third law? For every action there is an equal and opposite reaction. So if there is a reaction force, why don’t the two forces cancel each other out and the ball remain at rest?
That’s because the action and the reaction force don’t act on the same body. The reaction force exerted by the ball acted on your hand, and decelerated it, as your biceps tied to pull your hand forward. Since the force by the ball was decelerating your hand, it could not cancel out the force your hand was exerting on the ball.
Sweet. So far we’ve covered high school level physics. But honestly, I have seen Olympiad competitors, engineering students, and even PhD students mess up this simple question. Just needs a little misdirection.
Now, after we have kind of established Newton’s laws and their ‘infallibility’, in my next post, I am going to give you an example where Newton’s third law does not seem to work.

A reason to pursue science as a career

There is a weird old story in Hindu Mythology.
Indradyumna, the son of Bharat, was the greatest man on Earth. It was well known that there was no one to match his “Dharma-Swabhaav”, his righteousness. As a consequence of his good deeds, he ascended to Swarga (Heaven). There, for thousands of years, he enjoyed the limitless luxuries he earned as a consequence of his good deeds. But one day, Indra, the king of the lesser Gods, told him, “O King, you have done immense number of punyaas (good deeds) in your life and as a result you were here for a very long time. The time on earth past so much that now no one remembers any of your good deeds and hence it is time for you to leave heaven”. [Now, why the God king used such a long convoluted way of saying “Time’s up!” escapes me, but that’s pretty much how dialogues in most religious texts go.]
The rest of the story is about Indradyumna’s quest to find the one creature on the planet that remembered his good deeds.

Note to self: Must find out why a lot of famous Hindu are painted blue.

The crux of the story had always struck me as a kid. That even the deeds of the greatest man on earth are great as long as they are remembered.
There are more several ways to be remembered in history. Becoming a great philanthropist like Mother Teresa. Writing great work of literature like Shakespeare.
But for me, a great way to survive would be to make a scientific discovery.
Nothing underpins the impact of making scientific discoveries more than the story of Archimedes.  You know his story about him running in his birthday suit, crying ‘Eureka.’ If you had a good science teacher in your highschool, you might have heard him tell you that it was something about dipping things in water to determine their purity. But you need to delve a little deeper into the story to appreciate the timelessness of an epic scientific figure.

He probably wasn’t bald!

Archimedes died during the siege of Syracuse, during the second Punic War. The name of the war sounds unfamiliar, right? The Punic War took place between the Romans and the Carthaginians. Much like the first and second world wars, the battles saw great strides in scientific discoveries, with all the participants employing cutting edge war machines and military strategy to outclass their opponents. Over a hundred thousand soldiers died in the battles alone, in a war that lasted for seventeen years.
It is one of the battles that shaped human history as we know it. For one thing, if the Carthaginians had won the war, Jesus might not have been born. If you still are not convinced about the epicness of the war, just take a look at the map of the participating nations.
Second Punic War

The original “Second World War”

The fact of the matter is, the Second Punic War was at a time, as significant to human histories as the World Wars are to us. However, we barely remember it.
But we remember Archimedes and his naked run in the streets of Syracuse.
So it is not a far off bet to guess that one day, humanity will forget about the First World War, but remember Maxwell and his equations; we’ll forget about Hitler and the Second World War, but remember Albert Einstein’s theories.
And that is a compelling reason to pursue science as a career, for the remote chance that we might find something that lasts through humanity’s history.
Also, the work hours are nice.
Note: The post was inspired from Professor Evgeni Narimanov’s first lecture in his course ECE60400: Electromagnetic Field Theory. This was undoubtedly one of the best classes I have ever taken.
1. Wikipedia articles – Indradyumna, Second Punic War, List of battles by casualties.
2. Cartoon:
3. Map:  From the book Atlas of Empires by Peter Davidson.