Tuesday, February 28, 2012

Finding Explosives With Laser Beams.

The Raman spectroscope emits laser light, which is scattered at the sample and then collected by the telescope (left). (Credit: Vienna University of Technology)
Source: Science Daily
ScienceDaily (Feb. 27, 2012) — People like to keep a safe distance from explosive substances, but in order to analyze them, close contact is usually inevitable. At the Vienna University of Technology, a new method has now been developed to detect chemicals inside a container over a distance of more than a hundred meters. Laser light is scattered in a very specific way by different substances. Using this light, the contents of a nontransparent container can be analyzed without opening it.
Scattered Light as a "Chemical Fingerprint":
"The method we are using is Raman-spectroscopy," says Professor Bernhard Lendl (TU Vienna). The sample is irradiated with a laser beam. When the light is scattered by the molecules of the sample, it can change its energy. For example, the photons can transfer energy to the molecules by exciting molecular vibrations. This changes the wavelength of the light -- and thus its colour. Analyzing the colour spectrum of the scattered light, scientists can determine by what kind of molecules it must have been scattered.
Measuring over Great Distances -- with Highest Precision:
"Until now, the sample had to be placed very close to the laser and the light detector for this kind of Raman-spectroscopy," says Bernard Zachhuber. Due to his technological advancements, measurements can now be made over long distances. "Among hundreds of millions of photons, only a few trigger a Raman-scattering process in the sample," says Bernhard Zachhuber. These scattered particles of light are scattered uniformly in all directions. Only a tiny fraction travel back to the light detector. From this very weak signal, as much information as possible has to be extracted. This can be done using a highly efficient telescope and extremely sensitive light detectors.
In this project (funded by the EU) the researchers at TU Vienna collaborated with private companies and with partners in public safety, including The Spanish Guardia Civil who are are extremely interested in the new technology. During the project, the Austrian military was also involved. On their testing grounds the researchers from TU Vienna could put their method to the extreme. They tested frequently used explosives, such as TNT, ANFO or RDX. The tests were highly successful: "Even at a distance of more than a hundred meters, the substances could be detected reliably," says Engelene Chrysostom (TU Vienna).
Seeing Through Walls:
Raman spectroscopy over long distances even works if the sample is hidden in a nontransparent container. The laser beam is scattered by the container wall, but a small portion of the beam penetrates the box. There, in the sample, it can still excite Raman-scattering processes. "The challenge is to distinguish the container's light signal from the sample signal," says Bernhard Lendl. This can be done using a simple geometric trick: The laser beam hits the container on a small, well-defined spot. Therefore, the light signal emitted by the container stems from a very small region. The light which enters the container, on the other hand, is scattered into a much larger region. If the detector telescope is not exactly aimed at the point at which the laser hits the container but at a region just a few centimeters away, the characteristic light signal of the contents can be measured instead of the signal coming from the container.
The new method could make security checks at the airport a lot easier -- but the area of application is much wider. The method could be used wherever it is hard to get close to the subject of investigation. It could be just as useful for studying icebergs as for geological analysis on a Mars mission. In the chemical industry, a broad range of possible applications could be opened up.

Saturday, June 18, 2011

'Ultrawideband' Could Be Future of Medical Monitoring

Source: ScienceDaily

ScienceDaily (June 16, 2011) — New research by electrical engineers at Oregon State University has confirmed that an electronic technology called "ultrawideband" could hold part of the solution to an ambitious goal in the future of medicine -- health monitoring with sophisticated "body-area networks." Such networks would offer continuous, real-time health diagnosis, experts say, to reduce the onset of degenerative diseases, save lives and cut health care costs.
Some remote health monitoring is already available, but the perfection of such systems is still elusive.
The ideal device would be very small, worn on the body and perhaps draw its energy from something as minor as body heat. But it would be able to transmit vast amounts of health information in real time, greatly improve medical care, reduce costs and help to prevent or treat disease.
Sounds great in theory, but it's not easy. If it were, the X Prize Foundation wouldn't be trying to develop a Tricorder X Prize -- inspired by the remarkable instrument of Star Trek fame -- that would give $10 million to whoever can create a mobile wireless sensor that would give billions of people around the world better access to low-cost, reliable medical monitoring and diagnostics.
The new findings at OSU are a step towards that goal.
"This type of sensing would scale a monitor down to something about the size of a bandage that you could wear around with you," said Patrick Chiang, an expert in wireless medical electronics and assistant professor in the OSU School of Electrical Engineering and Computer Science.
"The sensor might provide and transmit data on some important things, like heart health, bone density, blood pressure or insulin status," Chiang said. "Ideally, you could not only monitor health issues but also help prevent problems before they happen. Maybe detect arrhythmias, for instance, and anticipate heart attacks. And it needs to be non-invasive, cheap and able to provide huge amounts of data."
Several startup companies such as Corventis and iRhythm have already entered the cardiac monitoring market.
According to the new analysis by OSU researchers, which was published in the EURASIP Journal on Wireless Communications and Networking, one of the key obstacles is the need to transmit large amounts of data while consuming very little energy.
They determined that a type of technology called "ultrawideband" might have that capability if the receiver getting the data were within a "line of sight," and not interrupted by passing through a human body. But even non-line of sight transmission might be possible using ultrawideband if lower transmission rates were required, they found. Collaborating on the research was Huaping Liu, an associate professor in School of Electrical Engineering and Computer Science.
"The challenges are quite complex, but the potential benefit is huge, and of increasing importance with an aging population," Chiang said. "This is definitely possible. I could see some of the first systems being commercialized within five years." Story Source:
The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by
Oregon State University.

Team Reports Scalable Fabrication of Self-Aligned Graphene Transistors, Circuits

Source: ScienceDaily

ScienceDaily (June 16, 2011) — Graphene, a one-atom-thick layer of graphitic carbon, has the potential to make consumer electronic devices faster and smaller. But its unique properties, and the shrinking scale of electronics, also make graphene difficult to fabricate and to produce on a large scale. In September 2010, a UCLA research team reported that they had overcome some of these difficulties and were able to fabricate graphene transistors with unparalleled speed. These transistors used a nanowire as the self-aligned gate -- the element that switches the transistor between various states. But the scalability of this approach remained an open question.
Now the researchers, using equipment from the Nanoelectronics Research Facility and the Center for High Frequency Electronics at UCLA, report that they have developed a scalable approach to fabricating these high-speed graphene transistors.
The team used a dielectrophoresis assembly approach to precisely place nanowire gate arrays on large-area chemical vapor deposition-growth graphene -- as opposed to mechanically peeled graphene flakes -- to enable the rational fabrication of high-speed transistor arrays. They were able to do this on a glass substrate, minimizing parasitic delay and enabling graphene transistors with extrinsic cut-off frequencies exceeding 50 GHz. Typical high-speed graphene transistors are fabricated on silicon or semi-insulating silicon carbide substrates that tend to bleed off electric charge, leading to extrinsic cut-off frequencies of around 10 GHz or less.
Taking an additional step, the UCLA team was able to use these graphene transistors to construct radio-frequency circuits functioning up to 10 GHz, a substantial improvement from previous reports of 20 MHz.
The research opens a rational pathway to scalable fabrication of high-speed, self-aligned graphene transistors and functional circuits and it demonstrates for the first time a graphene transistor with a practical (extrinsic) cutoff frequency beyond 50 GHz.
This represents a significant advance toward graphene-based, radio-frequency circuits that could be used in a variety of devices, including radios, computers and mobile phones. The technology might also be used in wireless communication, imaging and radar technologies.
The UCLA research team included Xiangfeng Duan, professor of chemistry and biochemistry; Yu Huang, assistant professor of materials science and engineering at the Henry Samueli School of Engineering and Applied Science; Lei Liao; Jingwei Bai; Rui Cheng; Hailong Zhou; Lixin Liu; and Yuan Liu.
Duan and Huang are also researchers at the California NanoSystems Institute at UCLA.
The work was funded by grants from National Science Foundation and the National Institutes of Health.
The research was recently published in the peer-reviewed journal Nano Letters. Story Source:
The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by
University of California - Los Angeles. The original article was written by Mike Rodewald.

Thursday, June 17, 2010

Here’s a rapid solution to find out how solar panels work.

What exactly is solar energy ?
Solar energy is radiant energy which is produced by the sun. Every day the sun radiates, or sends out, an enormous volume of energy. The sun radiates more energy in a single second than people have used since the beginning of time!
The energy of the Sun comes from within the sun itself. Like other stars, the sun is really a big ball of gases––mostly hydrogen and helium atoms.
The hydrogen atoms in the sun’s core combine to form helium and generate energy in a process called nuclear fusion.

During nuclear fusion, the sun’s extremely high pressure and temperature cause hydrogen atoms to come apart and their nuclei (the central cores of the atoms) to fuse or combine. Four hydrogen nuclei fuse to become one helium atom. However the helium atom contains less mass compared to four hydrogen atoms that fused. Some matter is lost during nuclear fusion. The lost matter is emitted into space as radiant energy.
It takes millions of years for the energy in the sun’s core to make its way to the solar surface, and somewhat over eight minutes to travel the 93 million miles to earth. The solar energy travels to the earth at a speed of 186,000 miles per second, the speed of light.
Only a small part of the energy radiated from the sun into space strikes the earth, one part in two billion. Yet this volume of energy is enormous. On a daily basis enough energy strikes the united states to supply the nation’s energy needs for one and a half years!

Where does all this energy go?
About 15 percent of the sun’s energy that hits our planet is reflected back into space. Another 30 percent is used to evaporate water, which, lifted in to the atmosphere, produces rainfall. Solar power is also absorbed by plants, the land, and the oceans. The remaining could be used to supply our energy needs.
Who invented solar technology ?
Humans have harnessed solar energy for hundreds of years. As early as the 7th century B.C., people used simple magnifying glasses to concentrate the light of the sun into beams so hot they would cause wood to catch fire. Over a century ago in France, a scientist used heat from a solar collector to create steam to drive a steam engine. In the beginning of this century, scientists and engineers began researching ways to use solar technology in earnest. One important development was a remarkably efficient solar boiler invented by Charles Greeley Abbott, an american astrophysicist, in 1936.

The solar water heater gained popularity at this time in Florida, California, and the Southwest. The industry started in the early 1920s and was in full swing just before World War II. This growth lasted before mid-1950s when low-cost natural gas had become the primary fuel for heating American homes.
People and world governments remained largely indifferent to the possibilities of solar technology until the oil shortages of the1970s. Today, people use solar technology to heat buildings and water and also to generate electricity.
How we use solar power today ?
Solar energy is employed in a variety of ways, of course. There are 2 standard forms of solar power:

* Solar thermal energy collects the sun's warmth through 1 of 2 means: in water or in an anti-freeze (glycol) mixture.

* Solar photovoltaic energy converts the sun's radiation to usable electricity.

Listed below are the five most practical and popular ways that solar energy is used:

1. Small portable solar photovoltaic systems. We see these used everywhere, from calculators to solar garden tools. Portable units can be utilized for everything from RV appliances while single panel systems are used for traffic signs and remote monitoring stations.

2. Solar pool heating. Running water in direct circulation systems via a solar collector is an extremely practical solution to heat water for your pool or hot spa.

3. Thermal glycol energy to heat water. In this method (indirect circulation), glycol is heated by sunshine and the heat is then transferred to water in a hot water tank. This process of collecting the sun's energy is more practical now than ever before. In areas as far north as Edmonton, Alberta, solar thermal to heat water is economically sound. It can pay for itself in three years or less.

4. Integrating solar photovoltaic energy into your home or office power. In most parts on the planet, solar photovoltaics is an economically feasible approach to supplement the power of your home. In Japan, photovoltaics are competitive with other forms of power. In the USA, new incentive programs make this form of solar technology ever more viable in many states. An increasingly popular and practical way of integrating solar energy into the power of your home or business is through the use of building integrated solar photovoltaics.

5. Large independent photovoltaic systems. For those who have enough sun power at your site, you could possibly go off grid. It's also possible to integrate or hybridize your solar energy system with wind power or other forms of renewable energy to stay 'off the grid.'

How can Photovoltaic panels work ?
Silicon is mounted beneath non-reflective glass to create photovoltaic panels. These panels collect photons from the sun, converting them into DC electrical energy. The energy created then flows into an inverter. The inverter transforms the power into basic voltage and AC electrical power.
Photovoltaic cells are prepared with particular materials called semiconductors for example silicon, which is presently the most generally used. When light hits the Photovoltaic cell, a certain share of it is absorbed inside the semiconductor material. This means that the energy of the absorbed light is given to the semiconductor.

The power unfastens the electrons, permitting them to run freely. Photovoltaic cells also have one or more electric fields that act to compel electrons unfastened by light absorption to flow in a specific direction. This flow of electrons is a current, and by introducing metal links on the top and bottom of the -Photovoltaic cell, the current can be drawn to use it externally.
What are the benefits and drawbacks of solar power ?

Solar Pro Arguments:

- Heating our homes with oil or natural gas or using electricity from power plants running with coal and oil is a reason for climate change and climate disruption. Solar power, on the other hand, is clean and environmentally-friendly.

- Solar hot-water heaters require little maintenance, and their initial investment could be recovered within a relatively limited time.

- Solar hot-water heaters can work in almost any climate, even just in very cold ones. You just need to choose the right system for your climate: drainback, thermosyphon, batch-ICS, etc.

- Maintenance costs of solar powered systems are minimal and also the warranties large.

- Financial incentives (USA, Canada, European states…) can reduce the price of the first investment in solar technologies. The U.S. government, for example, offers tax credits for solar systems certified by by the SRCC (Solar Rating and Certification Corporation), which amount to 30 percent of the investment (2009-2016 period).

Solar Cons Arguments:

- The initial investment in Solar Hot water heaters or in Solar PV Electric Systems is greater than that required by conventional electric and gas heaters systems.

- The payback period of solar PV-electric systems is high, as well as those of solar space heating or solar cooling (only the solar warm water heating payback is short or relatively short).

- Solar water heating do not support a direct in conjunction with radiators (including baseboard ones).

- Some air cooling (solar space heating and the solar cooling systems) are costly, and rather untested technologies: solar air conditioning isn't, till now, a really economical option.

- The efficiency of solar powered systems is rather influenced by sunlight resources. It's in colder climates, where heating or electricity needs are higher, that the efficiency is smaller.

About me - Barbara Young writes on
motorhome solar power in her personal hobby blog 12voltsolarpanels.net. Her work is centered on helping people save energy using solar power to reduce CO2 emissions and energy dependency.

Sunday, January 17, 2010

Hexapod robot moves in the right direction by controlling chaos.

Source: Scientific American

Given that robots generally lack muscles, they can't rely on muscle memory (the trick that allows our bodies to become familiar over time with movements such as walking or breathing) to help them more easily complete repetitive tasks. For autonomous robots, this can be a bit of a problem, since they may have to accommodate changing terrain in real time or risk getting stuck or losing their balance.
One way around this is to create a robot that can process information from a variety of sensors positioned near its "legs" and identify different patterns as it moves, a team of researchers report Sunday in Nature Physics. (Scientific American is part of Nature Publishing Group.)
Some scientists rely on small neural circuits called "central pattern generators" (CPG) to create walking robots that are aware of their surroundings. One of the challenges is that the robot typically needs a separate CPG for each leg in order to sense obstacles and take the appropriate action (such as stepping around a chair leg or over a rock).
Bernstein Center for Computational Neuroscience researcher Poramate Manoonpong and Max Planck Institute for Dynamics and Self-Organization researcher Marc Timme are leading a project that has created a six-legged robot with one CPG that can switch gaits depending upon the obstacles it encounters. The robot does this by manipulating the sensor inputs into periodic patterns (rather than chaotic ones) that determine its gait. In the future, the robot will also be equipped with a memory device that will enable it to complete movements even after the sensory input ceases to exist.
© Poramate Manoonpong and Marc Timme, University of Goettingen and Max Planck Institute for Dynamics and Self-Organization

Friday, January 15, 2010

Fleet of High-Tech Robot 'Gliders' to Explore Oceans.

Glider under water. (Credit: Holger v. Neuhoff, IFM-GEOMAR)
Source: ScienceDaily
ScienceDaily (Jan. 14, 2010) — The Leibniz Institute of Marine Sciences (IFM-GEOMAR) in Kiel, Germany, recently obtained the biggest fleet of so-called gliders in Europe. These instruments can explore the oceans like sailplanes up to a depth of 1000 metres. In doing so they only consume as much energy as a bike light. In the next years up to ten of these high-tech instruments will take measurements to better understand many processes in the oceans. Currently scientists and technicians prepare the devices for their first mission as a 'swarm' in the tropical Atlantic.
They may look like mini-torpedoes, yet exclusively serve peaceful purposes. The payload of the two-metre-long yellow diving robots consists of modern electronics, sensors and high-performance batteries. With these devices the marine scientists can collect selective measurements from the ocean interior while staying ashore themselves. Moreover, the gliders not only transmit the data in real time, but they can be reached by the scientists via satellite telephone and programmed with new mission parameters.
As such the new robots represent an important supplement to previous marine sensor platforms.
"Ten year ago we started to explore the ocean systematically with profiling drifters. Today more than 3000 of these devices constantly provide data from the ocean interior," explains Professor Torsten Kanzow, oceanographer at IFM-GEOMAR. This highly successful programme has one major disadvantage: the pathways of the drifters cannot be controlled.
"The new gliders have no direct motor, either. But with their small wings they move forward like sailplanes under water," says Dr. Gerd Krahmann, a colleague of Professor Kanzow. In a zigzag movement, the glider cycles between a maximum depth of 1000 metres and the sea surface.
"By telephone we can 'talk' to the glider and upload a new course everytime it comes up," explains Krahmann. A glider can carry out autonomous missions for weeks or even months. Every glider is equipped with instruments to measure temperature, salinity, oxygen and chlorophyll content as well as the turbidity of the sea water.
The IFM-GEOMAR has been the first institute in Europe to be committed to the new technology. "We tested different devices and we had to learn the hard way, too," oceanographer Dr. Johannes Karstensen says. "This way we have been able to contribute to the glider development, and now we have gathered knowledge required for successful glider operations," he adds.
Within the context of a special investment IFM-GEOMAR was able to obtain six new gliders adding to a total of nine altogether, which is the biggest fleet of that kind in Europe. Manufacturer of the IFM-GEOMAR-gliders is the Teledyne Webb Research Inc. in the USA.
A very successful mission using a single glider took place between August and October 2009 in the Atlantic Ocean, south of the Cape Verde Islands. The robot carried out measurements along a more than 1000 kilometres long track autonomously, before it was recovered by the German research vessel METEOR. The data collected are accessible online at
Now, for the first time the scientists in Kiel prepare a whole fleet of gliders for a concerted mission. After final tests the robots will be released mid-March 2010 at about 60 nautical miles north-east of the Cape Verde Island of Sao Vicente. For two months they will investigate physical and biogeochemical quantities of the Atlantic Ocean around the oceanographic long-term observatory TENATSO.
Goals of the experiment lead jointly by Prof. Torsten Kanzow, Prof. Julie LaRoche (marine biology) and Prof. Arne K├Ârtzinger (marine chemistry) are to get new insights into water circulation and stratification as well as their impact on chemical and biological processes. With the glider swarm the scientists can sample a complete "sea-volume" and not just a single point or a single cross-section in the ocean. The gliders will be remotely controlled from a control centre at the IFM-GEOMAR in Kiel.
"This technology enables us to observe the upper layers of the ocean much more effectively and thus much less expensive than previously," says Prof. Dr. Martin Visbeck, Deputy Director of the IFM-GEOMAR and Head of the research division Ocean Circulation and Climate Dynamics.
Story Source:
Adapted from materials provided by
Leibniz Institute of Marine Sciences (IFM-GEOMAR), via AlphaGalileo.

Thursday, January 14, 2010

Modified Mobile Phone Runs on Coca-Cola.

A modified Nokia cell phone that runs on Coca-Cola could run up to four times longer than a phone with a lithium ion battery. Image credit: Daizi Zheng.
Source: Physorg.com
Daizi Zheng, a Chinese developer who is currently based in London, has modified a Nokia cell phone to run on Coca-Cola or any other sugary solution.
Zheng says the modified phone can run three or four times longer on a single charge than a phone using a conventional , and can also be fully biodegradable.
As Zheng explains, a sugar-powered phone could potentially offer a much more environmentally friendly power source than lithium ion batteries. The new phone's bio battery, which basically acts as a , uses enzymes as the to generate from carbohydrates.
The phone can run for several hours, and produces water and carbon dioxide as the battery runs down. The phone can then be emptied out and refilled with more Coca-Cola.
Zheng designed the phone as a client project for Nokia, but there's no word on whether the company plans to incorporate the concept into future products.
"It brings a whole new perception to batteries and afternoon tea," Zheng wrote on her project's website.
More information: www.daizizheng.com