- Enbridge carries 318,000 barrels of oil per day
- Critical pipeline carries oil to U.S. markets, could cause price spike
- Two people killed, including a firefighter. Three reported injured.
- Estimates up to 20,000 barrels spilled
- Could be largest oil spill in US midwest after Kalamazoo last year by the same pipeline
- Company expects line to be back running late this week
- Here is a map of the Enbridge pipeline (in red)
UPDATE: Caused by a car accident between a Mustang and an SUV in a remote area. Enbridge calls the incident “an unusual occurrence.”
How to win a climate change argument, in one chart.
(via Slate Magazine)
The mantis shrimp is one of the most incredible creatures found in our oceans. Over millions of years, it has equipped itself with an arsenal to rival that of any other organism, besting the limits of human technology on more than one front.
Firstly, it packs the biggest punch of any predator, with a sophisticated muscle mechanism allowing acceleration in excess of 102,000 m/s2 to be attained and a speed of 23 m/s from a standing start, about the acceleration of a .22 calibre bullet. Because they strike so rapidly, they generate cavitation bubbles between the appendage and the striking surface.The collapse of these cavitation bubbles produces measurable forces on their prey in addition to the instantaneous forces of 1,500 newtons that are caused by the impact of the appendage against the striking surface, which means that the prey is hit twice by a single strike; first by the claw and then by the collapsing cavitation bubbles that immediately follow. With this ability to create extreme low pressure behind it’s extended arm, causing the water to spontaneously boil, no prey stands a chance. This action releases intense energy, enough to break sheets of glass. Even if the initial strike misses the prey, the resulting shock wave can be enough to kill or stun the prey.
Additionally, the mantis shrimp has the most sophisticated and extensive eyes of any known creature. With their unique shape and composition, the shrimp can see in most directions simultaneously, as well as observing more of the spectrum than us humans, both at the infra-red and ultra-violet ends.
Oh and it looks fucking beautiful.
In this video, researcher Leif Ristroph and his colleagues have used a clever way to simulate flapping flight, not by actuating their fliers but by oscillating the flow. The flow is driven by a speaker, which causes the air above it to move up and down. Using straws to simulate the honeycomb flow conditioners often used in wind tunnels helps smooth flow. The end result is a great table-top set-up for testing and refining miniature flier designs. The best fliers stay aloft thanks to asymmetry in the streamwise direction; when the air moves upward, the flier catches the air, maximizing drag so that it is carried upward. When the flow reverses, however, the shape of the flier is more streamlined, so the drag is reduced, helping the flier stay aloft. (Video credit: Science Friday/Leif Ristroph et al.)
Wind tunnel testing plays a major role in the planning of many space missions. Here a model of the Mars Sample Return Orbiter is tested at Mach 10 to determine the heat shield’s response to aerobraking off Mars’ atmosphere. The colors are the result of electron beam fluorescence, in which an electron gun is used to ionize molecules in the flow, which causes them to emit photons (light). The technique can be used for flow visualization—as in the case of the shock waves shown here—or to measure flow characteristics like density, temperature, and velocity. (Photo credit: Thierry Pot/DAFE/ONERA)
Canon 20D in Windows 7
Just got a new computer with Windows 7 (i know, its only days before windows 8 comes out, but i dont have much interest in it). Tried to pull some photos off of my 20D to make room on the CF card, but Windows wouldn’t properly obtain drivers for the camera.
After a quick search I found out that if you go into the camera menu and change the “communication” setting to PTP instead of the default, and plug the camera back into the computer Windows will automatically enable the correct drivers and everything will work as it should.
Using Netduino in Linux with Windows Virtual Machine
I have been programming a Netduino for some robotics projects and I just wanted to document some of the things that I’ve noticed with my setup. If your not familiar, netduino is an open source open hardware microcontroller that can be used for any number of projects from home automation, to art installations and can be programmed in C#. My interest in them is easy to program low cost robotics.
Setup
I use linux for work and on my laptop at home, so this was a hurdle I had to overcome in order to use the netduino. While there is an open source alternative to Microsoft’s .NET framework implementation (called mono) it doesn’t include the “micro” version of the framework required to code the microcontroller. It is possible to program the .NET micro framework in linux with mono it is super hacky, and to me, not worth the effort to setup.
I decided to use a virtual machine hosted inside of my Ubuntu operating system on my laptop. Oracle provides an excellent free virtualization solution called VirtualBox which is easy to obtain and install, and since I already had it, this is what I used.
Since I had a Windows XP cd kicking around, this is what I installed in my virtual machine to support the Microsoft .NET micro and interface to the netduino. The required software can be found here. Visual Studio makes programming and deploying to the netduino super easy and it’s great that the “express” version can be had for free from Microsoft. I installed 2010 for C# .NET which is still available and intended to work on XP.
I had forgotten that Windows takes forever to install and so do Visual Studio and the required .NET frameworks, but all you have to do is follow the order of download and install on the netduino page to ensure that you have done it properly.
Some things to keep in mind
Connecting the netduino (USB)
- The specifications on the netduino website says that USB is not officially supported as a protocol for a Linux/Mac system hosting a Windows virtual machine to connect to the netduino. I didnt’ realize this when I first got started, and it may explain some of the weirdness I have experienced, but it definitely seems to work just fine for me.
- You have to make sure that the netduino is accessible as a usb device to your virtual machine. Once you have connected the usb cable between your device and computer, go to the Devices menu in your virtual machine window and find the netduino under the usb category and select it.
- Once the netduino is available as a usb device to your virtual machine, Windows asks if you would like to install the required drivers. I’m not sure if this is required, but I did it successfully but selecting the default options all the way through the new hardware wizard.
Deploying code to the netduino
- In order to deploy the code to the netduino microcontroller, it must be selected as the target in your Visual Studio project’s properties (Properties menu option in the Project menu. Then select .NET Micro Framework from the list.) This involves changing the transport method to USB and the target to your netduino (mine showed up as Netduino_Netduino). You can deploy code and start debugging by pressing F5 or delecting Start Debugging in the Visual Studio Debug menu.
- If it doesn’t show up in the target list (or intermittently it seems to be disconnected/deployment fails) just unplug the usb cable and plug it back in. Then re-select the device as a usb device in the virtual machine’s menu.
- If the code builds correctly and netduino is attached, Visual Studio will program the microcontroller with your code and try to run it. When I do this Visual Studio indicates that it needs to reboot the netduino for the new code to run, and just sits there. I’m not sure if this is typical, but once this happens if I just press the reset button on netduino the netduino restarts and begins running my new code.
- If you stop debugging now (I get a warning when I opt to stop debugging, but you can just ignore it), you can unplug your netduino from the computer and run your new code by pressing its reset button provided you are still providing power to the unit. (I will write a post soon about creating a simple battery pack for the netduino with a 9v battery.)
MMP : error MMP0000: 0x80131700
You may get an error that says MMP and something about metadata. This apparently may happen with clean installs of XP where just the netduino .NET requirements are installed. I learned how to solve this issue here, but basically it involves copying the text below and saving it as MetaDataProcessor.exe.config in your ../Program Files/Microsoft .NET Micro Framework\v4.1\Tools folder. (Or installing .NET 3.5 SP1)
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<startup useLegacyV2RuntimeActivationPolicy="true">
<supportedRuntime version="v4.0.30319"/>
</startup>
</configuration>
Many common fluids—like air and water—are Newtonian fluids, meaning that stress in the fluid is linearly proportional to the rate at which the fluid is deformed. Viscosity is the constant that relates the stress and rate of strain, or deformation. The term non-Newtonian is used to describe any fluid whose properties do not follow this relationship; instead their viscosity is dependent on the rate of strain, viscoelasticity, or even changes with time. A neat common example of a non-Newtonian fluid is oobleck, a mixture of cornstarch and water that is shear-thickening, meaning that it is resistant to fast deformations. Like the cornstarch-based custard in the video above, these fluids react similarly to a solid when struck, resisting changing their shape, but if deformed slowly, they will flow in the manner of any liquid.
Flow visualization is a powerful design tool for engineers. When Google was interested in determining optimal configurations for their heliostat array, they turned to NASA Ames’ water tunnel facility to test upstream barriers to deflect flow off the heliostats. In each photo, flow is from left to right and fluorescent dye is used to mark streamlines and reveal qualitative flow detail. Upstream of the obstacles, the streamlines are coherent and laminar, but after deflection, the flow breaks down into turbulence. In this case, such turbulence is desirable because it lowers the local fluid velocity and thus the aerodynamic loads experienced by each heliostat, potentially allowing for a savings in fabrication. For more, see Google’s report on the project. (Photo credits: google.org)
In rowing, as in any water sport, drag comes in three varieties: skin friction, form (or pressure) drag, and wave drag. Skin friction comes from the friction between the hull and water causing the boat to drag water with it as it moves. This can be mitigated with the right materials and surface finish but will never be completely negligible. In fact, the racing shells used in rowing are unusual for boats because skin friction is their major source of resistance. This is because form drag, caused by the shape of the boat cutting through the water, and wave drag, the energy lost due to the waves that form along the hull, are small in racing shells due to their long, narrow, and streamlined shape. Because skin friction dominates among the three types of drag, the force a rower overcomes to move the boat is proportional to the hull’s velocity squared, and the power required to do so is proportional to the hull’s velocity cubed. This means that it is more efficient for rowers to keep a constant hull speed throughout a race than it is to start slow and speed up or start fast and slow down because the work (power x time) needed to keep a constant speed is smaller. For more on the physics of rowing, check out Anu Dudhia’s excellent website or this video from Physics of Life. (Photo credits: Ecouterre, AP)
FYFD is celebrating the Olympics by featuring the fluid dynamics of sport. Check out some of our previous posts, including what makes a pool fast, how divers reduce splash, and the aerodynamics of badminton.
This is pretty cool, historical maps overlayed upon google imagry basemaps. Interesting mapping contexts. I’d like to see someone warp modern data onto historical maps now.
It was just yesterday when we showed you what would happen if you got too close to a melting glacier in Greenland — a disturbing glimpse of what’s becoming a regular fixture in that part of the world.
Share Folders in Virtualbox OSE
I had some problems trying to mount shared folders in my virtualbox guest at work, so I thought I thought I would post some info to help others.
I installed guest additions and setup some shared folders to automatically mount. I couldn’t find where they were automatically mounting, and attempts to manually mount them were problematic.
It turns out that (at least in my case) the guest (Debian 6) was automatically mounting my shared folders in /media with prefixes of “sf” so my folders ended up like /media/sf_shared . Of course you need root or sudo access to get at the data when its there.
This video shows sea surface temperature results and their seasonal variation from a numerical simulation modeling circulation in the atmosphere and oceans. Modeling such enormous problems requires the development of reasonable models of the turbulent physics, clever algorithms to quickly progress the solutions, relatively low-fidelity (a single grid node may cover tens of kilometers), and enormous computing power. (Video credit: NOAA; via Gizmodo)
An interesting take on coffee use. I may try this strategy out to operate at peak efficientcy at work.
