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Archive for the ‘engineering’ Category

My experiment with GATE

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If you’re an undergraduate engineering/science student in India, and you plan to do your Master’s degree in some of India’s premier institutes of higher education (like the IITs or IISc), then you’ll have to write the Graduate Aptitude Test in Engineering (GATE).

The test is similar to the subject GRE. It consists of 60 multiple choice questions over a duration of 3 hours. The first 20 questions are worth 1 point, while the last 40 are worth 2 points for a total of 100 points with negative marks for incorrect answers. The engineeering test contains two sections. There’s a general engineering mathematics section as well as the specialized engineering subject.

In the summer of 2008, I had a wonderful experience participating in an undergraduate research project at the Indian Institute of Science in Bangalore. As a result, while I had applied towards a number of graduate schools in the US, I was also looking at the possibility of doing a ME degree at IISc. This meant that I had to register for and write the GATE in 2009.

The “online” registration process is actually a bit of a misnomer. I had to download the documents from the webpage, and fill in the relevant details and submit the printed documents at the GATE office. For details of the admission procedure and the structure of the test, visit the GATE website.

A couple of months after I had registered for the test, but before the actual examination date, I received an offer of admission towards a PhD at a well-recognized graduate program in the US which I plan to accept. So, I decided to write the GATE anyway for fun without any preparation. After all, what better way to test the conceptual knowledge that one is expected to acquire in four years of undergraduate education?

On the morning of February 8th 2009, I was off to write the test at the Santhom Hr. Sec. School, comforted with the knowledge that it didn’t matter one bit even if I completely messed it up. The location was pretty decent, and there was drinking water available, although the desks had less legroom than a typical Indian Airlines flight.

The engineering mathematics part of the test was pretty straight forward. Many of the questions were on multi-variable calculus and complex numbers. Since I don’t remember signing a non-disclosure form, I’ll reproduce some of the questions below.

  • The direction of largest increase of the function xy^3-x^2 at the point (1,1) is ?
  • The value of the limit as {x \rightarrow \pi/2} of (\cos{x})/(x-\pi/2)^2
  • Using the residue theorem, the value of the integral \oint (8-7z)/(z-4) dz around a circle with center at z=0, and radius=8 is?
  • Use the Gauss divergence theorem to evaluate \int \int (2x \hat{i}-2y\hat{j}+5z\hat{k})\cdot \hat{n}dS over a sphere of radius=3 centered at the origin

I was confident that I’d got most, if not all, of the math questions right, and was pretty pleased with my progress. That is, until I hit the chemical engineering section.

  • How does the power number vary with the Reynolds Number in a mixing tank operating in the laminar regime?
  • The active component of catalysts used in the steam reforming of methane to produce synthesis gas?
  • What is the Thiele modulus?
  • How does the frictional pressure drop across a packed bed vary with the superficial velocity in fully turbulent conditions?
  • How does the mass transfer coefficient vary with the diffusion coefficient in the penetration theory of mass transfer?

Embarrassingly, I had also forgotten which way the Biot number was defined (ie, convective/conductive or the other way?). I guess that since most of my exams in undergrad were open notes/open book, there wasn’t a need to actually commit definitions and formulae to memory, and my lack of preparation was very evident in this section.

However, further into the test, there were numerous standard “homework” problems which you could immediately identify if you’d done the relevant courses on heat transfer, transport phenomena, reaction engineering and process control, such as calculating the outlet temperatures of streams in heat exchangers, number of stages in distillation columns, mean residence time calculations, stability of control systems, etc.

Overall, I though that the test was set pretty well.

However, I get the feeling that the GATE doesn’t test the innate analytical skills of the student, as much as it tests a particular method of undergraduate education (the problem solving/number crunching method, which many students may not be exposed to). In my highly subjective opinion, I don’t think that the GATE should be required for admission to a graduate program. If there is a need for a “leveler test” to attempt to compare applicants between the multitude of universities in India, I think a test which focuses on basic analytical and verbal skills (like the GRE) is preferable.

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Written by parseval

March 16, 2009 at 4:51 am

Posted in education, engineering, personal

Tagged with ,

Sunday Video

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For more, check out this nice introductory post by Prof. Arunn Narasimhan on optimization and genetic algorithms.

Written by parseval

July 12, 2008 at 9:38 pm

This is why you should use SI units

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The recent initial success of NASA’s phoenix lander has led to a lot of attention and excitement about space exploration, and rightly so! However, things haven’t always been this peachy for NASA.

In December of 1998, NASA launched a spacecraft whose primary mission was to monitor the climate of mars from orbit, which was aptly titled the ‘Mars Climate Orbiter’. The total cost of the project was around 300 million dollars. As you’d have probably guessed by now, the mission ended in failure. As the spacecraft approached Mars, it received instructions to power its main engines in order to insert itself into the required orbit. In fact, as the NASA mission page documents, this is what should have happened.

The Mars Climate Orbiter will arrive at Mars on September 23, 1999. As it nears its closest point to the planet coming in over the northern hemisphere, the spacecraft will fire its 640-newton main engine for 16 minutes 23 seconds to brake into an elliptical capture orbit. The spacecraft will loop around Mars roughly once every 12 to 17 hours. The period of the capture orbit will increase if launch takes place on a later date, due to an increasing arrival velocity. If launch takes place at the end of the launch period in late December, the capture orbit period would be approximately 20 hours.

However, the orbiter never reemerged from behind Mars, and all contact was lost. What happened?

Amazingly, NASA messed up the units.

The peer review preliminary findings indicate that one team used English units (e.g., inches, feet and pounds) while the other used metric units for a key spacecraft operation. This information was critical to the maneuvers required to place the spacecraft in the proper Mars orbit.

Wow.

Written by parseval

May 30, 2008 at 1:07 am

Posted in engineering, history

Engineering

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The sticker for the vessel says, “Made from High Quality Stainless Steel”.

However, “high quality stainless steel” for the handle? Or, does this ingenious product have some other subtle use, and is in fact, not a cooking vessel as it so innocently looks?

Written by parseval

August 7, 2007 at 8:22 pm

Posted in engineering