Examples of jamming

http://www.metacafe.com/watch/1550345/breaking_up_a_traffic_jam/

I found this video of a guy who considers himself a "zen warrior who can shatter traffic jams as he approaches them."  He makes some valid points about not how traffic jams form, but how they break up.  He talks about leaving a big space in front of you, thereby eliminating stop and go driving, and thus eliminating the traffic jam in your lane.  He also discusses how traffic jams form at merging lanes - "cheaters" going up to the front and trying to fight their way into traffic.  By employing his big gap philosophy, he reasons that cars can merge smoothly into the lane, thus stopping the stop and go traffic that causes jams.

 

ps.  I also found an example of Stephen Marley jamming to a song he calls "the traffic jam." http://www.youtube.com/watch?v=AzOC46VIC-Y

Posted at 11:28PM Dec 01, 2008 by Victor Brozovsky in General  |  Comments[0]

Shockwave Traffic 2

Video Link

I posted this video previously for the engineering, but it also relates to this topic of jamming.  Because drivers cannot read each others minds collectively, and therefore cannot sync their spacing, they inadvertantly create spontaneous jams.  This act of varying their spacing creates a shock wave effect as soon as someone needs to slow down or realizes that they are too close to the car in front of them.  This shock wave effect shows how traffic jams can form without any bottlenecking.

Posted at 06:53PM Dec 01, 2008 by William Stoy in General  |  Comments[0]

Mandelbrot Set Song

Totally not relevant other than the fact that this song is amazing.

Linkage

Words

It made me laugh. A lot.

Posted at 11:40PM Nov 30, 2008 by Karin Hurwitz in General  |  Comments[0]

Traffic Engineering

Video Link

This also goes into next weeks topic about traffic, but understanding how traffic behaves is a major part of the job of a Transportation engineer.  Several Transportation Engineers and researchers from Japan created an experiment to show how some traffic jams form.  These "shockwave" traffic jams appear for no apparent reason to participating motorists, but they have a huge impact on the interstate.  Traffic engineers can increase speed limits or appeal to lawmakers to increase laws about the required car-lengths between cars.  This may not prove effective if people simply don't know about / don't follow the law, and it still doesn't prevent rubbernecking at an accident or the congestion at on and off ramps.

Posted at 07:51PM Nov 20, 2008 by William Stoy in General  |  Comments[0]

Destruction from Resonance

Both the Tacoma Bridge and the Millennium Bridge exhibited vibration induced by resonance.  A periodic force matched the natural vibration of the two structures, increasing the magnitude of the oscillations tremendously.  In the case of the Tacoma Bridge, wind passing over and around the bridge provided the external force.  For the Millenium Bridge, the people walking over the bridge caused the motion.  In each case, the motion of the bridge slightly altered the force, keeping it in resonance with the motion. 

A similar effect can be archived with a wine glass by using a sound waves as the driving force.  However, the sound is produced by a speaker and not coupled with the vibrations of the glass, so the experiment requires the speaker be tuned to almost exactly the same pitch as the glass.  Once that is done, the results are about the same.  a video is shown here

Posted at 04:54PM Nov 17, 2008 by Jeffrey Fowler in General  |  Comments[0]

Self-assembly of chemical bonds

http://www.youtube.com/watch?v=QqjcCvzWwww&feature=related

This video gives a quick explanation of the molecular forces that cause ionic and covalent bonds.  Here we see that the atoms try to achieve the most stable energy state by completing the octet.  We know from chemistry that the most stable state is the state of lowest energy for the system.  This next video gives a rather monotonic explanation of how energy is minimized by bonding.  http://www.youtube.com/watch?v=lKk_TUSEhTY  Of course, we assume that the atoms are close enough that it is preferable for them to bond with each other (obviously, as r->infinity, the energy is not minimized by bonding.)

PS  I happened upon this video while looking at self-assembly, and it's rather interesting - robots that self assemble.

Posted at 11:28PM Nov 07, 2008 by Victor Brozovsky in General  |  Comments[0]

Infarkt

In this video, you can see the effects of a heart arrhythmia.  The heart begins by beating normally, as soon as the arrhythmia sets in, the heart noticeably has trouble beating.  Towards the end of the video, the heart goes into full-on fibrillation and is unable to pump blood at all.

We know that one cause of such arrhythmia is an overactive sinus node, or another source of interference, sends out signals that cannot be interpreted by heart muscles because they are in a recovery period.  This causes chambers of the heart to beat out of sequence, and they cannot effectively pump blood.

Posted at 11:50PM Nov 06, 2008 by William Stoy in General  |  Comments[0]

Obituary: Anatol Zhabotinsky

There is a nice obituary for Anatol Zhabotinsky up at Nature

Posted at 10:50AM Nov 05, 2008 by DANIELS, KAREN in General  |  Comments[0]

Cardiac Arrhythmia

This video (url:  http://www.youtube.com/watch?v=xw4nDMgTOrw) is a visual depiction of cardiac arrhythmia. Cardiac arrhythmia generally refers to abnormal electrical activity in the heart. The heart can perform irregularly by beating too quickly or too slowly. A brief explanation of this phenomenon is offered in the video as well. The abnormal heart beat patterns seem to occur in some sort of chaotic manner.

Posted at 11:59PM Nov 03, 2008 by Daniel Evan Piephoff in General  |  Comments[0]

Plasma Ball Entropy

Most commonly, Plasma lamps are available in spheres and cylinders. Although there are many variations, a plasma lamp is usually a clear glass orb, filled with a mixture of various gases at low pressure, and driven by high frequency alternating current at high voltage generated by a high voltage transformer. A much smaller orb in its center serves as an electrode. Plasma filaments extend from the inner electrode to the outer glass insulator, giving the appearance of multiple constant beams of colored light (see corona discharge and electric glow discharge). The beams initially follow the electric field lines of the dipole, but move upwards due to convection.

Placing a hand near the glass alters the high-frequency electric field, causing a single beam to migrate from the inner ball to the point of contact. An electric current is produced within any conductive object near the orb, as the glass does not block the electromagnetic field created by the electric current flowing through the plasma (though the insulator does block the current itself). The glass acts as a dielectric in a capacitor formed between the ionized gas and the hand.

http://www.youtube.com/watch?v=YYqtJkactJI

(Note: For some reason, the add link button won't work for me. :( )

Posted at 11:48AM Oct 23, 2008 by Karin Hurwitz in General  |  Comments[0]

TATP Entropic Explosion

This video (http://www.youtube.com/watch?v=aKyNQ_Ky0h8&feature=related) [Sorry for the formatting; I can't for the life of me get the hyperlink tool to work, even after trying it on two different browsers and two different computers. After clicking on it, nothing pops up] depicts an entropic explosion using 115g of triacetone triperoxide (TATP) in a pipe bomb. In an entropic explosion the chemical reactants undergo a large change in volume without releasing much heat. In the explosion, not much energy is generated in the chemical bond formation in the reaction products, indicating that the reaction is not highly thermodynamically favored. Instead, the reaction involves an entropy burst, that of which is the result of the generation of ozone and acetone gas. This burst can be easilly seen and heard in the video, and it results in the destruction of a toy doll.

Posted at 10:52PM Oct 22, 2008 by Daniel Evan Piephoff in General  |  Comments[17]

The Dragon Fractal

This video explains something called "The Dragon Fractal". The way he explains it in the beginning makes the most sense to me. He says that it is like having a piece of paper that is folded in half infinitely many times and this is the image you get as you unfold it. This is a new fractal to me that seems a tad more interesting and "plausible" to me. The design is a perfect example of a fractal as it is made of smaller and smaller copies of itself.

Dragon Fractal

Posted at 01:01PM Oct 07, 2008 by Kristopher Dixon in General  |  Comments[0]

Ink in Water

While browsing youtube for "fractal water," I happened upon many interesting videos showing the fractal behavior of ink in water.  The first video shows ink being squirted into a glass of clear water, as well as the self- similar patterns that follow.  At first the ink drop splits into two drops, then the larger drop splits into three drops, each of which split into about three more drops, and so on, tracing out curves that resemble the roots of mangroves (speaking of which...).  These self-similar patterns are characteristic of fractals.

The second video shows a drop of ink falling into a smooth surface of water.  Fractal behavior is evident in multiple aspects of this video.  The first splash shows the red ink splashing up in approximately evenly spaced lines, each of which branches out and mixes with the clear water on its way up.  Furthermore, the formation of water droplets during this initial splash seems to be fractal in nature; the initial drop forms several drops, which in turn form multiple smaller drops.  As the video progresses, we see the splash form another central water droplet, which then falls onto the water's surface as the first one did.  This then creates a splash which forms yet another water droplet, and so on.  Of course this fractal behavior cannot proceed to infinity, since the force required to send the splash high enough to form another water droplet is diminished as time goes on, so it is not a true fractal.  However, for early values of t, the system exhibits fractal behavior.

first video: http://www.youtube.com/watch?v=VlAzyVx7N9M

second video: http://www.youtube.com/watch?v=CJ-AX1G0SmY

Posted at 11:10PM Oct 06, 2008 by Victor Brozovsky in General  |  Comments[0]

Fractals in Africa: A Religious Application of our Favourite Fractals

This is an interesting little research project, funded by the Fulbright Grant, for researcher Ron Eglash who looked at overhead photos of tribal African villages and saw fractals in the construction. So he went to Africa and discovered that fractals occurred in structures because the local religion was based on a kind of fractal pattern, with families and villages displaying self-similar behavior. He says at one point that, some of the fractals designed are intuitive while others are based on highly developed algorithms, where pieces are separated even by age groups, and are built recursively. There are references in the video to log log plots that reveal incredibly cost beneficial fences, built from reeds with a fractal pattern to prevent wind and dust from getting through the fence, There is also a reference to a religious algorithm that uses deterministic chaos in divination. Although the video is rather long, the topic is interesting and the speaker is engaging: truly worth watching.

http://www.youtube.com/watch?v=7n36qV4Lk94

Posted at 09:20PM Oct 06, 2008 by Garik Cruise Sadovy in General  |  Comments[0]

Fractals and Strange Attractors

I know that we have already discussed this topic but it seems to go hand in hand with fractals.

I have found several instances where fractals take the form of strange attractors, such as the Lorenz Attractor and the Feigenbaum Attractor.


Do they look familiar? Both of these Strange Attractors have characteristics of fractals. For example, self-similarity is highlighted in the Feigenbaum Attractor. Both Attractors create smaller versions of themselves as the pattern continues, however as we studied in our last topic, they are never repeating.

Another example is the Henon Attractor:
 
I couldn't find the name for this:

(If the animation isn't working then here is the website that it came from.
It shows how a fractal can stretch and fold to create the many layers of similar shapes.
Stranger Attractors are considered fractals but not all fractals are strange attractors. They follow most of the fractal guidelines but are very specific, hence why they are called STRANGE attractors. They are generally created from two or three equations, some more complicated than others.

Posted at 11:47AM Oct 06, 2008 by Cathalyn Van Deusen in General  |  Comments[0]