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Tuesday, 25 March 2014

Solar cell emits own light source.

An overachieving material known as Perovskite could act as a solar cell by day, light source by night, scientists have found.

In an exciting solar breakthrough, scientists have discovered that a material known as Perovskite is not only capable of converting sunlight into electricity, it also emits its own light source.
The discovery was published in Nature Materials this week, and could lead to shop front signs, lamps and even mobile devices and tablets that soak up power from the Sun during the day and then light up at night.
The researchers from Nanyang Technological University in Singapore found that Perovskite, which was already one of the most promising materials for creating high-efficiency, cheap solar cells, is also highly suited for making lasers of different frequencies. The material is five times cheaper than current silicon-based solar cells.
In a press release, physicist Sum Tze Chien explained that he made the disovery by chance when he asked his postdoc Xing Guichuan to shine a laser on a new hybrid Perovskite solar cells they're currently developing and they started glowing brightly.
“By tuning the composition of the material, we can make it emit a wide range of colours, which also makes it suitable as a light emitting device, such as flat screen displays.”

Tuesday, 4 March 2014

A Solar-Powered Drone Designed To Fly For Five Years Nonstop

Titan Aerospace will test a drone that could track hurricanes, spot pirates, and more.

If a drone never had to land, it could track hurricanes, spot pirates and smugglers, follow animal migrations, and even act as an auxiliary GPS. In essence, it would be a geostationary satellite without the expense of going to space. Later this year, the company Titan Aerospace will test a drone that could do just that. The Solara 50, named for its 50-meter wingspan, will fly at 65,000 feet—above most other aircraft and above weather that could disturb its flight and block the sun, its source of power. Titan will market it as an “atmospheric satellite."
Don't believe us? Watch the video below.

Tuesday, 18 February 2014

Single chip device to provide real-time 3-D images from inside the heart, blood vessels.

A single-chip catheter-based device that would provide forward-looking, real-time, three-dimensional imaging from inside the heart, coronary arteries and peripheral blood vessels is shown being tested.

Researchers have developed the technology for a catheter-based device that would provide forward-looking, real-time, three-dimensional imaging from inside the heart, coronary arteries and peripheral blood vessels. With its volumetric imaging, the new device could better guide surgeons working in the heart, and potentially allow more of patients' clogged arteries to be cleared without major surgery.

The device integrates ultrasound transducers with processing electronics on a single 1.4 millimeter silicon chip. On-chip processing of signals allows data from more than a hundred  on the device to be transmitted using just 13 tiny cables, permitting it to easily travel through circuitous blood vessels. The forward-looking images produced by the device would provide significantly more information than existing cross-sectional ultrasound.
Researchers have developed and tested a prototype able to provide image data at 60 frames per second, and plan next to conduct animal studies that could lead to commercialization of the device.
"Our device will allow doctors to see the whole volume that is in front of them within a blood vessel," said F. Levent Degertekin, a professor in the George W. Woodruff School of Mechanical Engineering at the Georgia Institute of Technology. "This will give cardiologists the equivalent of a flashlight so they can see blockages ahead of them in occluded arteries. It has the potential for reducing the amount of surgery that must be done to clear these vessels."
Details of the research were published online in the February 2014 issue of the journal IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control. Research leading to the device development was supported by the National Institute of Biomedical Imaging and Bioengineering (NIBIB), part of the National Institutes of Health.
This is a single-chip catheter-based device that would provide forward-looking, real-time, three-dimensional imaging from inside the heart, coronary arteries and peripheral blood vessels is shown on the tip of a finger. A microscope image of the device is shown behind it.

"If you're a doctor, you want to see what is going on inside the arteries and inside the heart, but most of the devices being used for this today provide only cross-sectional images," Degertekin explained. "If you have an artery that is totally blocked, for example, you need a system that tells you what's in front of you. You need to see the front, back and sidewalls altogether. That kind of information is basically not available at this time."
The single chip device combines capacitive micromachined ultrasonic transducer (CMUT) arrays with front-end CMOS electronics technology to provide three-dimensional intravascular ultrasound (IVUS) and intracardiac echography (ICE) images. The dual-ring array includes 56 ultrasound transmit elements and 48 receive elements. When assembled, the donut-shaped array is just 1.5 millimeters in diameter, with a 430-micron center hole to accommodate a guide wire.
Power-saving circuitry in the array shuts down sensors when they are not needed, allowing the device to operate with just 20 milliwatts of power, reducing the amount of heat generated inside the body. The ultrasound transducers operate at a frequency of 20 megahertz (MHz).
Imaging devices operating within blood vessels can provide higher resolution images than devices used from outside the body because they can operate at higher frequencies. But operating inside  requires devices that are small and flexible enough to travel through the circulatory system. They must also be able to operate in blood.
Doing that requires a large number of elements to transmit and receive the ultrasound information. Transmitting data from these elements to external processing equipment could require many cable connections, potentially limiting the device's ability to be threaded inside the body.
Degertekin and his collaborators addressed that challenge by miniaturizing the elements and carrying out some of the processing on the probe itself, allowing them to obtain what they believe are clinically-useful images with only 13 cables.
"You want the most compact and flexible catheter possible," Degertekin explained. "We could not do that without integrating the electronics and the imaging array on the same chip."
Based on their prototype, the researchers expect to conduct animal trials to demonstrate the device's potential applications. They ultimately expect to license the technology to an established medical diagnostic firm to conduct the clinical trials necessary to obtain FDA approval.
For the future, Degertekin hopes to develop a version of the device that could guide interventions in the heart under magnetic resonance imaging (MRI). Other plans include further reducing the size of the device to place it on a 400-micron diameter guide wire.

Carbon dioxide from exhaust fumes used to make new chemicals.

To stop global warming, most governments are advocating reducing the amount of carbon dioxide (CO₂), a greenhouse gas, put into the atmosphere. But some argue that such action won’t be enough – we will need to remove CO₂ already present.
The reduction of CO₂ is a big challenge, as it requires large amounts of renewable energy. Until then, short-term solutions to remove CO₂ from fossil fuel power plants is becoming necessary, including carbon capture and storage (CCS). The other option is to use the storage part, as new research from Korea shows, and to use CO₂ directly from exhaust gases to make new chemicals.

Catch me if you can

Carbon capture involves the “capture” of CO₂, either by a chemical or physical process. Often CO₂ from a exhaust gas stream is captured by nitrogen containing compounds called amines. The reaction results in the formation of solid chemicals. These can be heated, allowing the CO₂ to be released, which can then be compressed, transported and stored in geological features, such as depleted oil fields, or used as raw material in chemical factories.
Although trees and some microbes can capture CO₂ and use it as fuel, humans have struggled to replicate the process on a large scale. Most chemical reactions involving CO₂ require expensive catalysts, high temperatures, or high pressures to make it react. The most common use of CO₂ as a chemical feedstock is in the formation of urea, which is found in around 90% of the world’s fertilisers.
In the new research, published in the journal Angewandte Chemie, Soon Hong and colleagues from the Institute for Basic Science in South Korea have caught CO₂ from exhaust gas and used it for many reactions that make useful chemicals. One type is called alkynyl carboxylic acid, which has many uses such as making food additives. The other, cyclic carbonate, is used to make polymers for cars and electronics. Cyclic carbonates can also be used in place of phosgene, which is a very reactive and highly toxic chemical that is used as a starting material to make a wide variety of useful products.
Hong also used highly pure CO₂, which is sold at a high price and required lots of energy to make, in the same chemical reactions and found there was hardly any difference in the final yield (the amount of product formed minus wastage).

Use me if you do

Like CCS technologies, Hong passes exhaust fumes through a solution of amines, where CO₂ is captured and other gases pass unreacted. Then the resulting salt is heated to yield pure CO₂ for chemical reactions. Hong can recycle the amine solution at least 55 times without loss in yield.
In another research paper just published in Nature Communications, Matthias Beller and colleagues at the University of Rostock in Germany show a new reaction that can use CO₂. The reaction is called alkene carbonylation, and it usually required the use of carbon monoxide (CO), which, as home detectors know well, is a highly toxic and flammable gas.
CO₂ has previously been used in the synthesis of carboxylic acids by using diethylzinc as one of the drivers of the reaction. But diethylzinc is flammable in air. Using the reaction Beller can make chemicals are found in varnishes and paints. The researchers carried out a number of reactions but most importantly confirmed that the source of the newly formed C-O bond was CO₂. This work shows CO₂ can be used as a viable alternative to carbon monoxide in carbonylation reactions and increasing the importance of CO₂ in the chemical industry.
While this is good news, these advances don’t offset the energy needed to trap and use CO₂. They will help increase the demand of CO₂ at industrial scale, and may then drive CCS and renewable energy technologies to become cheaper.

Monday, 17 February 2014

Researchers build world's most powerful terahertz laser chip.

University of Leeds researchers have taken the lead in the race to build the world's most powerful terahertz laser chip.

A paper in the Institution of Engineering and Technology's (IET) journal Electronics Letters reports that the Leeds team has exceeded a 1 Watt output power from a quantum cascade terahertz laser.
The new record more than doubles landmarks set by the Massachusetts Institute of Technology (MIT) and subsequently by a team from Vienna last year.
Terahertz waves, which lie in the part of the electromagnetic spectrum between infrared and microwaves, can penetrate materials that block visible light and have a wide range of possible uses including chemical analysis, security scanning, medical imaging, and telecommunications.
Widely publicised potential applications include monitoring pharmaceutical products, the remote sensing of chemical signatures of explosives in unopened envelopes, and the non-invasive detection of cancers in the human body.
However, one of the main challenges for scientists and engineers is making the lasers powerful and compact enough to be useful.
Professor Edmund Linfield, Professor of Terahertz Electronics in the University's School of Electronic and Electrical Engineering, said: "Although it is possible to build large instruments that generate powerful beams of terahertz radiation, these instruments are only useful for a limited set of applications. We need terahertz lasers that not only offer high power but are also portable and low cost."
The quantum cascade terahertz lasers being developed by Leeds are only a few square millimetres in size.
In October 2013, Vienna University of Technology announced that its researchers had smashed the world record output power for quantum cascade terahertz lasers previously held by Massachusetts Institute of Technology (MIT). The Austrian team reported an output of 0.47 Watt from a single laser facet, nearly double the output power reported by the MIT team. The Leeds group has now achieved an output of more than 1 Watt from a single laser facet.
Professor Linfield said: "The process of making these lasers is extraordinarily delicate. Layers of different semiconductors such as gallium arsenide are built up one atomic monolayer at a time. We control the thickness and composition of each individual layer very accurately and build up a semiconductor material of between typically 1,000 and 2,000 layers. The record power of our new laser is due to the expertise that we have developed at Leeds in fabricating these layered semiconductors, together with our ability to engineer these materials subsequently into suitable and powerful laser devices."
Professor Giles Davies, Professor of Electronic and Photonic Engineering in the School of Electronic and Electrical Engineering, said: "The University of Leeds has been an international leader in terahertz engineering for many years. This work is a key step toward increasing the power of these lasers while keeping them compact and affordable enough to deliver the range of applications promised by terahertz technology."