Archive for the ‘Engineering’ Category

Engineers, please write blog or diary

August 22, 2009
An engineer stands next to a 3 percent-scale Saturn V model in the Transonic Dynamics Tunnel at NASA Langley Research Center in 1966. Thomas Ivanco prepares a model of Ares I-X for testing in the Transonic Dynamics Tunnel at NASA Langley Research Center.
1966 2006-2008

As the date of July 20 is approaching, celebration of the 40th anniversary of Landing on the Moon is getting more and more attentions. Let us read two related stories about NASA. The first one is “From Generation to Generation: Filling the Knowledge Gaps“:



How to avoid AdBlock?

July 7, 2009


When I posted my entry “Ad Block will continue while its creator dies“, I got a comment from Niudy:

Online advertising is an important link in Internet business food chain. It is like this diagram.
advertiser -> free media -> customer -> advertiser
If advertising is removed from chain because of ad block, then free media can not survive, we can not get free information from Internet any more. Let me ask this “Do you want to pay Yahoo for news and stock info?”. If you say no, then you can not refuse watching ads on Yahoo.


Build and Launch Your First Model Rocket

July 5, 2009
  1. Get a Michaels’ coupon either from a Sunday newspaper or search online. Michaels store accepts coupons printed from Internet.
  2. Go to a local Michaels Store and buy the following items:
    • 2.1. a model rocket from ESTES (I bought “Chrome Domes” and “Metalizer”, make sure the launch altitude is less than 700 ft unless you are willing to go to a rural area to launch your rocket);
    • 2.2. a bag of recovery wadding (they look like toilet paper but do NOT use toilet paper instead);
    • 2.3. a tube of plastic cement (you can use other glues if they are stronger);
    • 2.4. a pack of motors that your model rocket requires (I bought B6-4 and a pack contains three engines with igniters. My rocket needs one engine for each launch. So, I can launch three times).
  3. Follow the instruction to assemble the rocket. You might need additional tools: sand paper, scissors, masking tape. When you put the fin onto the rocket tube, make sure that the lug (the part glued onto the body) is aligned between two fins (see video
  4. Do not put the engines on to the rocket unless you are at the launch site.
  5. LUNAR makes the launch of model rockets available at Moffett Field (on Highway 101). It happens every third Saturday morning until 1 p.m (For July 2009, see my note below). Before you go, check the website ( and make sure it is not rescheduled since this may happen. Also, print the access procedure ( and bring with you to the launch site. The cost is $10 per family plus 25 cents for each launch. Upon your arrival at the gate at Moffett Field, show your driver’s license to the guard and tell him that that you have a model rocket in your car and then follow the designed path to the launch site. It is near the air traffic control tower.
  6. Don’t forget to bring snacks, drinking water, camera, folding chairs, umbrella, sunglasses, and sun blocks. Also, bring the assembling kits as you might need to do some quick fix. The rockets are reusable. Enjoy!
  7. There are two museums here too: Moffett Field Historical Society Museum and NASA Ames Exploration Center. The exploration center is free. Nearby is a gift shop. Everything is tax free in the shop. At the next highway exit, there is a Computer History Museum. The admission is free too.
  8. There are many readings on the internet on model rockets. Just google key words: build model rocket.
  9. To celebrate the 40 anniversary of Lunar landing of Apollo Program, NASA Ames will hold several activities on Sunday, July 19, 2009. The model rocket launch date is also changed from Saturday, July 18 to Sunday, July 19. This is a one-time change.

Can students post their homework on internet before due date?

June 27, 2009

With big surprise, I read this article “Student challenges prof, wins right to post source code he wrote for course“. I am not surprised that the professor was against the posting. I am surprised that the school approved the posting. Clearly, there is a loophole in school policy. (more…)

RSS — root sum square

June 19, 2009


My colleagues keeps talking about RSS and for sometime I didn’t know what they were talking about. I used my favorate desktop dictionary traydictionary which queries from Cambridge Dictionary of American English but find nothing. I looked up to Wikipedia and found that RSS could mean many many things (see TheFreeDictionary as well). I finally figured it out: it is the acronym of “Root Sum Square”. It is actually a very popular word in the scientific world.


sin(x), degree or radian?

May 4, 2009

For function y = sin(x), is x in degree or radian? This was a question I asked students many time when I was teaching. In using a calculator, either one is okay as long as the correct setting is in place. But not in actual scientific computation. Recently, I found a bug in my C++ code where I had a variable in degree, but the internal math library of C++ assumes it is in radian.

Normal distribution function

April 21, 2009

Can one find an analytic function in the “normal” sense for the the following integral?

The answer is “no”. Here by “normal” sense, I mean a combination of algebraic, trig, exp, log functions. In fact, function

is the distribution function of normal distribution. One engineer came to me and asked this question. He spent hours trying to integrate this function. In the scientific world, everyone needs solid mathematical skills. If you happen to see this entry and you are a college engineering student, I hope this story helps you in some way.

Engineering students, you may need multiple programming languages

April 16, 2009

Last month, after I posted an entry “Engineering Professors, Please Teach Some Programming Languages“, I received two well thought comments:

spinoza1111 (from his article “‘Academic” as a term of abuse‘, I know he dislikes FORTRAN because of “Go To”):

Interesting comment.

I worked as a programmer at Princeton and wound up “teaching at Princeton”. That is: the university takes the position that computer science and other engineering students MAY NOT study programming in formal Princeton classes, but are expected, as computer science students, to know C and Java upon matriculation. Therefore I was asked to teach C at Princeton.

This elitist philosophy also appears in Princeton’s math department, which offers no classes before Calculus.

Increasingly, programming is part of high school. My kid learned it in HS.

As to your hires knowing Fortran, this could be a problem in the years to come. It’s very unpopular in academia, and your hires will need training in its idiosyncracies. “Structured” Fortran was developed to avoid some of Fortran’s classic problems, but legacy code may not use the new features.

My view is that at University, students have the right to learn Truth and Beauty for a few years, and that for this reason, they shouldn’t be taught about Fortran, and I say this as one who, in 1971, debugged a nonworking Fortran compiler in object code to make it available to students. If industry uses legacy code, it should be ready to train students in older programming languages.

Otherwise, there is a danger, given the glamour and authority of university material, that students will repeat Fortran’s mistakes.

Fortran WAS a mistake. It has caused many engineering problems, including recent “credit crisis” problems because Fortran, sad to say, is used for financial modeling and speculation. Because auditors like your hire aren’t trained in it, they “audit around” it only to discover, too late and in the current crisis, that financial models built in Fortran have serious deficiencies including loss of the address of the original debtor in a securitized mortgage and circular derivatives where a is priced on b, b is priced on c, and c upon…a.

Now, Fortran doesn’t force the Fortran programmer to make these mistakes, but it does set a terrible example of “down and dirty” design which is psychological reinforcement for modern errors.

dougaj4 (an Excel advocator, see his articles ““, “Gaussian Quadrature” and “Evaluate integrals to a specified tolerance“, etc.):

There are some things that are better learnt at university, and some that are better learnt “on the job”. In my opinion coding in specific languages is definitely in the latter group, although the basics of programming probably comes in the former.

So it seems quite reasonable to me that students should only have experience in coding Matlab, although personally I’d suggest Excel VBA which would allow the teaching of the same basics, plus proficiency in a tool of wider general use.

Now I see resistance from educators and they probably have their point too. But the reality is that industry does not soly rely on Matlab or any exclusive programming language. In fact, there are emerging new languages coming to the world. Moreover, a language is not simply a tool to do engineering work. It is a training on how to think, how to do engineering work. I hope I will get another change to write more about it. For now, without being able to tell professors to teach various programming languages, I would suggest that engineering students be ready to learn and use other languages that you do not learn in class. An eager-to-learn attitude is very important as you can not tell your boss that you are unable to do the work because you didn’t learn it at school.

Dell shipment is async with shipping list

April 10, 2009

I bought a Dell desktop 3 years ago. It came with a re-installation CD and a driver CD. Everything worked nicely until recently when its performance is significantly down turned. I finally decided that it was time to reinstall the operation system, and that was the time when unexpected things started to happen. (more…)

YouTube: Space Shuttle TPS

March 25, 2009

This NASA video segment explores how the space shuttle is able to go from frigid temperatures in space to extremely hot temperatures when entering the earths atmosphere. Find out how experts use sand to help protect the space shuttle successfully travel from one temperature to the next.