Entropy and Chaos: Order and Disorder in the Universe
Thursday Dec 04, 2008
Grains Flowing from a Hopper
This video is of grains that are held in a vertical, 2-D hopper with a hole at the bottom. As the grains attempt to flow out there are a number of mild jams that occur due to the size and the nature of the grains. It is also an added bonus that the is polarized light. Because of the polarized aspect, you can see a flash of light whenever the grains are pushed together. This example if very similar to the one that was presented in the lab.Posted at 09:31PM Dec 04, 2008 by thomas stuart mccawley in MediaHunt6 | Comments[0]
On-ramp Bottleneck
When traffic is merging from an on-ramp onto a highway, a bottleneck can occur. This video shows cars merging onto the highway in slow moving traffic. Because there is no space between cars on the highway, the cars on the on-ramp have to come to a stop and wait to merge. This leads to a line of stopped cars on the on ramp. Bottlenecks occur when there is insufficient space for the cars on the road.
Posted at 01:23AM Dec 04, 2008 by Samantha Baughman in MediaHunt5 | Comments[0]
Tuesday Dec 02, 2008
Ice jam
This video illustrates a natural source of jamming: ice flow on Mimico Creek. Due to different breaking rates, the ice is seen to build up in a stationary jam, and then return to flowing downstream. Like we discussed in class, it it likely that bottlenecks (in the form of a narrowing stream, fallen logs, unmelted ice, and other obstacles) played a role in this behavior. While ice does not display the same sorts of inhibitions that people do (slowing down to avoid collision, etc), varying currents in the stream probably play a role in seemingly "random" build ups.
Posted at 05:36PM Dec 02, 2008 by Mary Burroughs in MediaHunt6 | Comments[0]
Simulator of Granular Flow
This video simulates the irregularity of granular flow through a "hopper". As the materials flow out, they form a canonical structure which also is formed because of the jamming properties of the material. I think this is a good illustration before Thursday's class, as Dr. Daniels experiments a lot with these kinds of materials (I think).Posted at 04:11PM Dec 02, 2008 by Adam Keith in MediaHunt6 | Comments[0]
Traffic!
While this is bascially just a video of an ordinary traffic jam, it was more interesting to me than that. As you watch, you can get a clear view of how one or two drivers can cause a huge change in the flow of traffic; it is very similar to the Lorenz model, where just a few decimal places made a significant difference in the result. I also thought that it was neat how the car traffic continued to jam up, while people traffic continued to nonchalantly meander through the cars - in this instance, it was obvious that the size of the particle had an effect on its mobility thru jams.Posted at 04:02PM Dec 02, 2008 by Molly Wright in MediaHunt6 | Comments[0]
Black Friday Shoppers
http://www.youtube.com/watch?v=HZJVZ2p223o&feature=related http://www.youtube.com/watch?v=aeSgBL7gpAk&feature=related (Only watch the first 30 seconds) (Also, I have no idea how to link on a Mac, my bad) <-- Delete afterwards? :D thx I'm not sure how many of you have ever gotten up up three o'clock in the morning to get in line at Wal-Mart, Target, Best Buy, Circuit City or any other main participate of the phenomena that is the day after Thanksgiving, also known as Black Friday. A side note, my father and I do this as a tradition. Most of the time, I don't go to bed the night before, but that's not relevant. What is relevant is that my father and I have another tradition. Making sure people don't cut the line. Because there is nothing more annoying that waiting outside for two hours in the cold to get a HD TV, than to have people pull up ten minutes before the doors open and take advantage of the mayhem that ensues when the doors finally open. Regardless, let's analyze what happens before, during, and after the doors have been open. Like I mentioned before in my personal anecdote, the line starts to form depending on the type of store and what the sale is. People who go for Best Buy will get in line the morning before (missing Thanksgiving with the family which is very tacky. :| ) just to get at the front of the line. The line will continue to form until about a half an hour before the doors open. This is when people start to hang on the other side of the main road (that runs in front of the store) and wait to jump in line. At a certain point (as seen in the video around 0:11-0:20) you can see people start to come out of their cars and jump in line. Around 0:30, all mayhem breaks out and people attempt to push their way through the double doors, creating a bottleneck jam. After the congestion forms, all source of general humanity is lost and the line is disrupted creating chaos. Solution to this mess? Either a) get in line first or b) don't go.Posted at 03:48PM Dec 02, 2008 by Karin Hurwitz in MediaHunt6 | Comments[0]
Monday Dec 01, 2008
Traffic Simulator
this simulator, already linked, may be used to highlight some key points pertaining to traffic jams.
This simulation allows one to control a small section of imaginary highway. Ideally, one would be able to model the jamming that has been proven experimentally to occur without bottlenecks. These jams arise from the small fluctuations in driving made by the operators, and unfortunately will not arise in this simulation. However, these non-bottleneck jams have been proven to occur when the traffic density reaches a certain critical point. While one can not adjust the density very subtly through the slight non-uninformities of the vehicles velocities and driving styles that trigger true jams, one may still control the density.
By setting the incoming cars to a constant amount, and the cars entering from off ramps to zero, one creates a stable stream. The density may be increased at the on ramp by adding a single car. while very crude, it very roughly simulates the "phase change" occurring at the critical density. at this point, a jam will appear behind the car that will persist until the number of all incoming cars has been significantly reduced.
Posted at 11:52PM Dec 01, 2008 by Jeffrey Fowler in MediaHunt5 | Comments[0]
[Jams]
This is an image of intestinal blockage due to the congestion of parasitic roundworms. It is cause by the worms invading and multiplying the the host. This cause cause death because of the interuption of bodily functions.
Posted at 11:35PM Dec 01, 2008 by Detric Robinson in MediaHunt5 | Comments[0]
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
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]
Calculations of Jamming and Blood Clotting
I've linked a video here that describes superficially the process of blood clotting through a graphic model, but the graphics are quite good. This is a very important kind of jam, as it can mean the difference between life and death, but what can we say about blood clots and their likeliness of forming?
http://www.youtube.com/watch?v=fjjEiVeYRNg&feature=related
In addition, here is a link that will take you to an article about some engineers that came up with a model of dense granular flows that can depict some of the aspects of jams. This knowledge has important implications for medical problems such as blood clots.
http://www.sciencedaily.com/releases/2008/04/080425130102.htm
Posted at 05:20PM Dec 01, 2008 by Garik Cruise Sadovy in MediaHunt5 | Comments[0]
I-880 Traffic Simulation
This video shows a computerized traffic simulation of Interstate 880, connecting San Francisco and Oakland. The video lacks sound effects or narration, but it very thoroughly models the traffic flows along I-880. Traffic simulations are shown at various projected times and from different heights/levels of magnification.Posted at 03:04AM Dec 01, 2008 by Daniel Evan Piephoff in MediaHunt6 | Comments[0]
Traffic Simulation
There is a good video of a traffic simulation seen here. Similar to in the video that was included in the readings you can see that the location of the jam is moving against the flow of the traffic. Included in the info was a link to an applet available here. This is a very good applet which can simulate many different traffic situations to show how and where the jamming occurs.Posted at 02:47AM Dec 01, 2008 by Timothy Michael Dannenhoffer in MediaHunt6 | Comments[0]
Sunday Nov 30, 2008
Mandelbrot Set Song
Totally not relevant other than the fact that this song is amazing.
It made me laugh. A lot.
Posted at 11:40PM Nov 30, 2008 by Karin Hurwitz in General | Comments[0]