Wednesday, January 25, 2012


It occurred to me that the last few products Apple has introduced all start with the letters i and p (iPod, iPhone, iPad).  Does this mean that they will continue this tradition when they introduce their new TV product and call it iPictureShow?

Thursday, January 19, 2012

Flux capacitor

Back to the future is a wonderful sci-fi film that is funny and light-hearted. I have seen the movie many times and I always chuckled when they mention the term "Flux Capacitor".  It sounded like someone took two random technical words and mashed them together.  In the movie, an elderly scientist tells the protagonist that the Flux Capacitor is what makes time travel possible.  From high school physics, we know that a capacitor is an electronic device used to store energy, and it is used in almost every electronic device, whether they are analog or digital.  Examples where capacitors are useful include audio filters, power line regulators, and dynamic memory (DRAM).  The basic design of a capacitor consists of two plates with a dielectric in between.  Applying a potential difference on the plates create an electric field between the plates where electrical energy is stored.  The strength of the electric field E is the potential difference V across the plates divided by the distance d between the plate. The electric flux Φ in the capacitor is the strength of the electric field E multiplied by the area A of the plate.  For a fixed voltage drop V across the plates,  Φ = VC/ε is proportional to the capacitance C.  Thus one can argue that the normal capacitor that we all know is in fact a flux capacitor!

In recent years, there have been advances in creating ultracapacitors or supercapacitors, i.e. capacitors that can store a large amount of energy. Some of these capacitors that are available today can have an energy density of up to 30Wh/kg.  Imagine that we have 10 kg of such capacitors. If we can fully charge them and then discharge them within 0.89 milliseconds, we would have an average power surge of 300Wh /0.89x10-3s = 1.21348 Gigawatts which should be sufficient to activate the time machine!

Sunday, January 8, 2012

Left or right?

I always wondered why various professions and technical fields have different names for left and right.  For instance, in optometry, OD (Oculus Dexter) and OS (Oculus Sinister) stands for right eye and left eye respectively.  Dexter and Sinister are the Latin words for right and left.  On a ship, the left and right side of the boat for someone on the ship facing the front of the ship are called port and starboard respectively.  My guess for the reason to introduce these terms is that when two people are facing each other and communicating it is not clear whose left and right sides are meant.  The following story told by my wife's aunt could also be another reason why such terms are used.  During a driver's test, the following exchange occurred:
Examiner: "Turn left at the intersection."
She: "Turn left, right?"
Examiner: "Right."
She turned right at the intersection and failed the test.

There are similar terms for other sides of an object as well.  For instance, the terms bow and stern are used to denote the front and back of a ship respectively and dorsum and ventrum denote the back and front sides of upright animals such as humans (or the upper and lower side of animals such as fish).

Saturday, January 7, 2012

Random thoughts on 2012

With the beginning of a new year, my thoughts went to what 2012 will bring.  I just read several articles that make me hopeful in 2012.  First, there is a blog entry in Design News by Alexander Wolfe postulating that engineering and engineers will be more appreciated.  Second, the latest issue of IEEE Spectrum has a Top Tech special report for 2012, and several of the innovations showcased are truly game-changing.  I am especially intrigued by the life sciences related innovations, such as the bionic legs, bionic eye, and automated medical diagnostic tool based on the Watson supercomputer.

On an another note, 2012 is the Alan Turing year, celebrating a century of Alan Turing's birth.  Turing made significant contributions to artificial intelligence (Turing test), theoretical computer science (Turing machine and uncomputable functions), cryptography (Breaking the Enigma code) and mathematical biology (Turing patterns and morphogenesis).  Speaking of computers, we recently visited the excellent Computer History Museum in Mountain View, CA and I am amazed how much progress has been made in computing within a single (human) lifetime.  To wit, I have owned several pieces of the (somewhat obsolete) artifacts that are on display in the museum, including a Commodore VIC-20 computer with an audio cassette tape drive, 5-1/4 inch and 3-1/2 inch floppy disks, abacus, dot matrix printer, and a sliderule.  I told my son that he should keep his old portable game machines and mp3 players, as they will invariably wind up in the museum someday.

Several cycles starts (ends) in 2012.  For instance, in 2012 the Mayan long count calendar will reach the end of a Baktun cycle which occurs every 394 years or so.  The sun reaches its peak in solar activity in 2012 as part of a 11-year cycle.

Some other fun facts about the year 2012:
  1. 2012 is a leap year and contains a leap month in the Chinese lunar calendar.  
  2. 2012 has 5 Wednesdays in February.
  3. 2012 has exactly 3 Friday the 13th.