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September 18, 2006, 9:20 PM CT

Engine On A Chip Would Be Best The Battery

Engine On A Chip Would Be Best The Battery Professor Alan Epstein
MIT scientists are putting a tiny gas-turbine engine inside a silicon chip about the size of a quarter. The resulting device could run 10 times longer than a battery of the same weight can, powering laptops, cell phones, radios and other electronic devices.

It could also dramatically lighten the load for people who can't connect to a power grid, including soldiers who now must carry a number of pounds of batteries for a three-day mission -- all at a reasonable price.

The scientists say that in the long term, mass-production could bring the per-unit cost of power from microengines close to that for power from today's large gas-turbine power plants.

Making things tiny is all the rage. The field -- called microelectromechanical systems, or MEMS -- grew out of the computer industry's stunning success in developing and using micro technologies. "Forty years ago, a computer filled up a whole building," said Professor Alan Epstein of the Department of Aeronautics and Astronautics. "Now we all have microcomputers on our desks and inside our thermostats and our watches".

While others are making miniature devices ranging from biological sensors to chemical processors, Epstein and a team of 20 faculty, staff and students are looking to make power -- personal power. "Big gas-turbine engines can power a city, but a little one could 'power' a person," said Epstein, whose colleagues are spread among MIT's Gas Turbine Laboratory, Microsystems Technology Laboratories, and Laboratory for Electromagnetic and Electronic Systems.........

Posted by: John      Permalink         Source

September 18, 2006, 8:44 PM CT

Large Objects Can Follow The Rules Of The Microscope

Large Objects Can Follow The Rules Of The Microscope Miles Blencowe (Photo by Joseph Mehling '69)
Miles Blencowe, a quantum theorist with the physics and astronomy department at Dartmouth, is part of a team working to connect the macroscopic and the microscopic worlds by seeing if they can make larger objects obey the laws of quantum mechanics, where things can be in two places at once.

In the Sept. 14 issue of the journal Nature, the scientists report that they are much closer to making this classical-quantum connection with an experiment to determine the position of a vibrating beam measuring one-thousandth of a millimeter in width. While still tiny, the beam comprises about ten billion atoms, and it represents a much larger system than has been considered to date.

Blencowe explains that this field of research attempts to reconcile the inherent contradiction between the quantum world of microscopic or atomic-sized systems and the classical or macroscopic world of well-localized trees, buildings and cars that we live in. At some point, the quantum becomes the classical as objects get larger and larger, and researchers want to know how that crossover occurs.

"Quantum mechanics predicts that if you try to measure the position of an object accurately, you will disturb its position, so you can never precisely know where the object is," says Blencowe. "That disturbance was exactly what we saw in the larger system".........

Posted by: Edwin      Permalink         Source

September 18, 2006, 8:25 PM CT

Taming Tricky Carbon Nanotubes

Taming Tricky Carbon Nanotubes MIT researchers have discovered that certain molecules can attach themselves to metallic carbon nanotubes without interfering with the nanotubes' exceptional ability to conduct electricity.
Based on a new theory, MIT researchers may be able to manipulate carbon nanotubes -- one of the strongest known materials and one of the trickiest to work with -- without destroying their extraordinary electrical properties.

The work is published in the Sept. 15 issue of Physical Review Letters, the journal of the American Physical Society.

Carbon nanotubes -- cylindrical carbon molecules 50,000 times thinner than a human hair -- have properties that make them potentially useful in nanotechnology, electronics, optics and reinforcing composite materials. With an internal bonding structure rivaling that of another well-known form of carbon, diamonds, carbon nanotubes are extraordinarily strong and can be highly efficient electrical conductors.

The problem is working with them. There is no reliable way to arrange the tubes into a circuit, partly because growing them can result in a randomly oriented mess resembling a bowl of spaghetti.

Scientists have attached to the side walls of the tiny tubes chemical molecules that work as "handles" that allow the tubes to be assembled and manipulated. But these molecular bonds also change the tubes' structure and destroy their conductivity.

Now Young-Su Lee, an MIT graduate student in materials science and engineering, and Nicola Marzari, an associate professor in the same department, have identified a class of chemical molecules that preserve the metallic properties of carbon nanotubes and their near-perfect ability to conduct electricity with little resistance.........

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September 14, 2006, 8:47 PM CT

Ferns Provide Model For Tiny Motors

Ferns Provide Model For Tiny Motors
Researchers looked to ferns to create a novel energy scavenging device that uses the power of evaporation to move itself -- materials that could provide a method for powering micro and nano devices with just water or heat.

"We've shown that this idea works," said Michel Maharbiz, assistant professor of electrical engineering and computer science and principal investigator in the group that built the device. "If you build these things they will move. The key is to show that you can generate electricity from this."

As often happens, the research started while doctoral student Ruba Borno was exploring another idea entirely. Borno was interested in mimicking biological devices, specifically microchannels that plants use to transport water, so Maharbiz gave her a book on plants.

But something else in the book caught her attention - the section on how ferns spread their spores.

"It's essentially a microactuator," said Maharbiz, meaning that the fern sporangium transforms one form of energy, in this case heat via the evaporation of water, into motion. When the cells in the outer wall of the sporangium were water logged, the sporangium remained closed like a fist, storing the spores safely inside. But when the water in the outer wall evaporated, it caused the sporangium to unfurl and eject the spores into the environment.........

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September 14, 2006, 6:52 PM CT

Atlantis In Space

Atlantis In Space
Birds don't fly this high. Airplanes don't go this fast. The Statue of Liberty weighs less. No species other than human can even comprehend what is going on, nor could any human just a millennium ago. The launch of a rocket bound for space is an event that inspires awe and challenges description.

Pictured above, the Space Shuttle Atlantis lifted off to visit the International Space Station during the morning of 2006 September 9. From a standing start, the two million kilogram rocket ship left to circle the Earth where the outside air is too thin to breathe and where there is little noticeable onboard gravity. Rockets bound for space are now launched from somewhere on Earth about once a week.........

Posted by: Edwin      Permalink         Source

September 14, 2006, 6:37 PM CT

Multi-Dimensional Human Embryo

Multi-Dimensional Human Embryo
collaboration funded by the National Institute of Child Health and Human Development (NICHD) to produce and make available over the internet a three-dimensional image reference of the Human Embryo based on magnetic resonance imaging.

The collection of images is intended to serve students, researchers, clinicians, and the general public interested in studying and teaching human development.........

Posted by: Nora      Permalink         Source

September 14, 2006, 6:30 PM CT

Refuge For Neanderthals?

Refuge For Neanderthals?
The completion of a 7-year excavation of a site in southern Spain provides some evidence that neanderthals may have lived for thousands of years longer than was previously thought.

Clive Finlayson led the international team of palaeoanthropologists, which discovered 103 neanderthal artifacts, including spear points and knives, while excavating Gorham's Cave near the Rock of Gibraltar. Most of these artifacts have been dated to about 28,000 years before present (BP), and some are dated as late as 24,000 years BP.

The study, reported in an advance online publication at Nature, led Finlayson and his team to conclude that an isolated population of neanderthals lived in the region surrounding Gorham's cave until about 28,000 years BP. This is the latest recorded date yet for neanderthals, and is at least 2,000 years later than previous estimates. It again raises the possibilty that early modern humans and neanderthals interbred.

The findings hint at a scenario in which neanderthals sought refuge in the southern-most point of the Iberian peninsula at a time when they had been wiped out from the rest of Europe, and when modern humans were expanding across the continent. Finlayson, an evolutionary biologist at the Gibraltar Museum, speculates that neanderthals were driven south because of climatic changes to which they could not adapt quickly enough.........

Posted by: Nora      Permalink         Source

September 14, 2006, 4:50 AM CT

Molecular Sieve For Protein Research

Molecular Sieve For Protein Research
New MIT technology promises to speed up the accurate sorting of proteins, work that may ultimately aid in the detection and treatment of disease.

Separating proteins from complex biological fluids such as blood is becoming increasingly important for understanding diseases and developing new treatments. The molecular sieve developed by MIT engineers is more precise than conventional methods and has the potential to be much faster.

The team's results appear in recent issues of Physical Review Letters, the Virtual Journal of Biological Physical Research and the Virtual Journal of Nanoscale Science and Technology.

The key to the molecular sieve, which is made using microfabrication technology, is the uniform size of the nanopores through which proteins are separated from biological fluids. Millions of pores can be spread across a microchip the size of a thumbnail.

The sieve makes it possible to screen proteins by specific size and shape.

In contrast, the current technique used for separating proteins, gel electrophoresis, is time-consuming and less predictable. Pore sizes in the gels vary, and the process itself is not well understood by scientists.

"No one has been able to measure the gel pore sizes accurately," said Jongyoon Han, the Karl Van Tassel Associate Professor of Electrical Engineering and Biological Engineering at MIT. "With our nanopore system, we control the pore size precisely, so we can control the sieving process of the protein molecules".........

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September 14, 2006, 4:42 AM CT

Serious Vulnerabilities In e-Voting Machines

Serious Vulnerabilities In e-Voting Machines Highlighting security vulnerabilities in electronic voting machines Credit: John Jameson, Princeton University
In a paper published on the Web today, a group of Princeton computer researchers said they created demonstration vote-stealing software that can be installed within a minute on a common electronic voting machine. The software can fraudulently change vote counts without being detected.

"We have created and analyzed the code in the spirit of helping to guide public officials so that they can make wise decisions about how to secure elections," said Edward Felten, the director of the Center for Information Technology Policy, a new center at Princeton University that addresses crucial issues at the intersection of society and computer technology.

The paper appears on the Web site for the Center for Information Technology Policy.

The scientists obtained the machine, a Diebold AccuVote-TS, from a private party in May. They spent the summer analyzing the machine and developing the vote-stealing demonstration.

"We observed that the machine is vulnerable to many extremely serious attacks that undermine the accuracy and credibility of the vote counts it produces," wrote Felten and his co-authors, graduate students Ariel Feldman and Alex Halderman.

In a 10-minute video on their Web site, the scientists demonstrate how the vote-stealing software works. The video shows the software sabotaging a mock presidential election between George Washington and Benedict Arnold. Arnold is reported as the winner even though Washington gets more votes. (The video is edited from a longer continuously shot video; the long single-shot version will be available for downloading from the center's site as well.).........

Posted by: John      Permalink         Source

September 13, 2006, 4:50 AM CT

Plastic Replicas Of Real Cells

Plastic Replicas Of Real Cells Real or replica?
Call them genuine fakes. Brown University biomedical engineer Diane Hoffman-Kim and her research team have made plastic replicas of real cells through a novel two-part molding process. The copies looked so authentic, Hoffman-Kim couldn't tell if they were real or rubber at first.

"When I saw the images from the microscope, I said, 'OK, I can't tell the difference,'" Hoffman-Kim said. "It was pretty amazing - and just what we wanted".

A description of the replicas, their ability to support cell growth, and their possible applications in science and medicine are published in Langmuir, a journal of the American Chemical Society.

The main cells used in the experiments were Schwann cells, which protect peripheral nerves by wrapping around their axons to create insulating myelin sheaths. Schwann cells also direct axon growth during cell development and repair.

Hoffman-Kim, an assistant professor in the Department of Molecular Pharmacology, Physiology and Biotechnology and the Division of Engineering, said the realistic replicas could be used in laboratories to help researchers understand how these critical support cells sustain and direct nerve growth.

The replicas could also, eventually, be used in hospitals to help doctors regenerate nerves. If a patient's nerves are severed during an auto accident or other injury, a device coated with the imitation cells - a contraption called a nerve guidance channel - could be implanted into the injured area to help stimulate nerve growth and repair damaged tissue. Tissue engineers around the world are testing nerve guidance channels in animals and, in a few cases, in humans.........

Posted by: John      Permalink         Source

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