Researchers experimenting with the properties of Graphene have discovered that when the single-atom-thick sheet is exposed to extreme low temperatures and high magnetic field it has the ability to filter electrons according to their spin direction.
At room temperature and with no magnetic field the flake of graphene functions as a normal conductor with electrons flowing throughout the sheet. With the application of a magnetic field perpendicular to the sheet the electrons migrate out to the sheet edges while the rest of the sheet has the properties of an insulator. Current flow around the edges is either clockwise or anticlockwise depending on the orientation of the field (known as the quantum Hall effect).
When the MIT researchers switched a second magnetic field in the same plane as the Graphene sheet they found that electrons move around the edge in either clockwise or counterclockwise direction depending on the electron’s direction of spin. [via]
Graphene could be good for Quantum Computing - [Link]
Jie Qi from the MIT Media Lab and Bunnie from Studio Kosagi are hoping to crowdfund their idea for a new method of circuit building called Circuit Stickers.
A crossover between high tech and arts and craft, Circuit Stickers are not a serious prototyping tool but aim to find new uses for easily configurable electronics circuits so that they can be incorporated into other media such as books (basic science or fiction) or even wearable electronics.
Interconnect and power tracks made from sticky copper tape (or other conducting material) are laid out on any non conducting surface such as paper, material or flexible fabric. The individual components come ready-mounted and connect to the copper tracks via pads with sticky anisotropic (Z) tape. These can be peeled off later for reuse. There are two kits available containing a sketchbook to take you through the basics, colored LEDs, sound, light and trigger sensors and a tiny microcontroller with an ISP programming connector. That old Tee shirt looking a bit tired? Spruce it up with a running light display. [via]
Circuit Stickers: Cut and Paste Circuitry - [Link]
MIT has designed an ultra-low cost “flow” battery that it claims will store 10-times as much energy as lithium-ion while consuming 10,000 times less power, making it a candidate to meet the Department of Energy’s target of less than $100 per kilowatt-hour for grid-scale deployment. [via]
MIT’s flow battery simplifies rechargeable technology by eliminating the ion-exchange membranes. The lower solid graphite electrode reduces liquid bromine to hydrobromic acid, while hydrogen is oxidized at the upper porous electrode.
Flow Batteries Go Mainstream - [Link]
Over 500 courses from the world’s leading universities – right at your fingertips.
The project — http://www.onlinecourses.com — is a free and comprehensive resource that is a collection of open college course that spans videos, audio lectures, and notes given by professors at Harvard, Princeton and MIT. They offer highly relevant courses such as iPhone Application Development from Stanford and Cyber Humor from Oxford. This is a wonderful resource for those looking to explore additional educational topics and to see what college level course has to offer.
Top Online Courses on the Web - [Link]
Researchers at MIT have designed a novel device the size of a U.S. quarter that harvests energy from low-frequency vibrations, such as those that might be felt along a pipeline or bridge. The tiny energy harvester — known technically as a microelectromechanical system, or MEMS — picks up a wider range of vibrations than current designs, and is able to generate 100 times the power of devices of similar size.
To harvest electricity from environmental vibrations, researchers have typically looked to piezoelectric materials, or PZT, such as quartz and other crystals. Various designs are based on a small microchip with layers of PZT glued to the top of a tiny cantilever beam. As the chip is exposed to vibrations, the beam moves up and down like a wobbly diving board, bending and stressing the PZT layers. The stressed material builds up an electric charge, which can be picked up by arrays of tiny electrodes. However, the beam itself has a resonant frequency and outside of this frequency, the beam’s response drops off, along with the amount of power that can be generated. [via]
New MEMS Device Generates More Energy From Small Vibrations - [Link]
Gil Junqueira write:
It has been 6 weeks since I last reviewed this course. At that time, I was just about to take the mid-term exam. Now it is 6 weeks later — and 14 weeks since the beginning of the class. I finally received my certificate of completion.…
I have to say that these 14 weeks were somewhat painful, as the necessary study required to complete homework in time and keep up with class materials were in direct conflict with my work schedule and ability to spend time with family. This wasn’t without warning, as MIT personnel did indicate that 8 to 10 hours of study time per week would be required in order to keep up with the course.
But at the end, despite all the hours spent on the computer cranking out code to solve problems late at night, (I gave up on doing the math by hand after week and so should you if you take this course in the future) I would do it all over again. This was by far one of the best electronics courses I have taken anywhere. While the material was not completely new to me (I took electronics courses before), the way it was presented was…
MITx / edX 6.002x Circuits and Electronics Course Review - [Link]
Joint partnership builds on MITx and Harvard distance learning; aims to benefit campus-based education and beyond. EdX is a not-for-profit joint venture between Harvard University and the Massachusetts Institute of Technology to offer online versions of their classes and those of other universities. At the same time, edX will support Harvard and MIT faculty in conducting research on teaching and learning on campus through tools that enrich classroom and laboratory experiences. The goal of this initiative is to create a global community of online learners while improving education for everyone. To learn more about edX, visit http://www.edxonline.org.
MIT and Harvard announce edX - [Link]
Ultra-efficient LED puts out more power than is pumped in (Wired UK) – [via]
MIT physicists have managed to build a light-emitting diode that has an electrical efficiency of more than 100 percent. You may ask, “Wouldn’t that mean it breaks the first law of thermodynamics?” The answer, happily, is no.
The LED produces 69 picowatts of light using 30 picowatts of power, giving it an efficiency of 230 percent. That means it operates above “unity efficiency” — putting it into a category normally occupied by perpetual motion machines.
Ultra-efficient LED puts out more power than is pumped in - [Link]
MITx 6.002 – [via]
6.002x (Circuits and Electronics) is designed to serve as a first course in an undergraduate electrical engineering (EE), or electrical engineering and computer science (EECS) curriculum. At MIT, 6.002 is in the core of department subjects required for all undergraduates in EECS.
The course introduces engineering in the context of the lumped circuit abstraction. Topics covered include: resistive elements and networks; independent and dependent sources; switches and MOS transistors; digital abstraction; amplifiers; energy storage elements; dynamics of first- and second-order networks; design in the time and frequency domains; and analog and digital circuits and applications. Design and lab exercises are also significant components of the course. You should expect to spend approximately 10 hours per week on the course.
MITx 6.002 Circuits and Electronics course - [Link]
The Fourier transform is a method for representing an irregular signal as a combination of weighted sine waves or ‘frequencies’. To calculate it quickly the Fast Fourier Transform (FFT) was devised some 50 years ago and ever since people have been searching for methods to make it even faster. At MIT a group of researchers has now developed an algorithm that, in a large range of practically important cases, achieves an up to a tenfold speed increase.
Signals whose Fourier transforms contain a relatively small number of strong frequencies are called ‘sparse’. In nature, most of the normal signals are sparse. The new algorithm determines the weights of the strongest frequency components contained in a signal; the sparser the signal, the greater the speedup the algorithm provides. Indeed, if the signal is sparse enough, the algorithm can simply sample it randomly rather than reading it in its entirety. [via]
EFFT – the Even Faster Fourier Transform - [Link]