New Phosphors could make LEDs To Shine More Like Natural Sun

LEDs are more efficient and have longer lifespan than incandescent and fluorescent lights. But technically it is still a challenge to make LED to produces warm, white light like sunlight. It turns out that creating phosphors that can emit a broad spectrum of wavelengths mimicking natural light is a tricky business.

Natural light composes spectrum from ultraviolet to infrared (250 nm to 1800 nm of wavelength). When ultraviolet photons generated from LED hit a phosphor, white light will be emitted. The problem is that the spectrum of this LED's white light isn't broad enough to mimic sunlight, as shown below.

Scientists from Oak Ridge and Argonne national labs and the University of Georgia, U.S.A., are working together to develop a new group of phosphors that glow in a broader part of the spectrum.

“It’s hard to get one phosphor that makes the broad range of colors needed to replicate the sun," said John Budai, an Oak Ridge materials scientist. “One approach to generating warm-white light is to hit a mixture of phosphors with ultraviolet radiation from an LED to stimulate many colors needed for white light."

They are growing and testing nanocrystals composed of europium oxide and aluminum oxide powders. Europium is a rare-earth element that has exceptional phosphorescent qualities, which glow in lots of different colors — some are orange, purple, green or yellow.

They are using X-rays to understand how atoms are arranged in the phosphorescent materials. Once they figure out how altering crystal growing conditions change the colors emitted, they hope to create lighting close to natural sunlight.

Source: http://www.greenbiz.com/blog/2013/07/04/new-materials-could-mean-natural-lighting-leds

Flexible Glass Could Make Solar Power Cheaper

U.S.A. National Renewable Energy Laboratory have built flexible solar cells using a thin and pliable kind of glass, called Willow glass, from Corning, the maker of iPhone screen's cover glass. The new solar cells could potentially make rooftop solar power far cheaper.

Conventional solar panels are heavy, bulky, and breakable, which makes them expensive to transport and install. Installation cost has been one of the largest parts of the overall cost of rooftop solar system. An average rooftop solar system in California costs US$6.14 per watt, while some solar panels sell for less than US$1 a watt in many cases.

Willow glass solar shingles are lightweight and could be nailed to a roof in place of conventional shingles. It would simplify the installation and reduce overall cost. Also, unlike other solar shingles making from plastic, Willow glass is very good at sealing out the solar elements from air and moisture, which helps solar cells last for decades.

Willow glass also makes it possible to use cadmium telluride as the solar cell material. This is the only material that’s been able to successfully challenge conventional silicon solar cells at a large, commercial scale. Cadmium telluride solar cells need to be made on a transparent material. Other flexible, transparent materials either can’t handle the high temperatures needed to make the solar cells, or they block too much light, reducing efficiency.

Willow glass solar cell is still in the proof-of-concept status. There are still a way from commercialization. In addition to improving efficiency, it will be necessary to develop a manufacturing process and equipments to handle larger flexible solar cells.

Source: http://www.technologyreview.com/news/516471/flexible-glass-could-make-tablets-lighter-and-solar-power-cheaper/

99% Of Android Devices Are In Threat Due To Android's App Vulnerability

Finally, Android platform is no longer immune from hacking. Bluebox Security has found a vulnerability in Android platform which could allow hackers to turn virtually any Android app into a malicious “zombie”. This would allow hackers to silently and remotely control a device's function, without raising the attention of the phone owner, Google or the app developer. This vulnerability dates back to Android 1.6 and could affect any of the 900 million Android devices in the market.

BlueBox Security's CTO Jeff Forristal revealed the company found a method by which a hacker could modify an app’s APK code without breaking the cryptographic signature used to authenticate it. Since verified apps are granted complete access to the Android system and all applications on a phone, the security weakness is potentially huge.

Forristal also mentioned that Apps listed on the Google Play store are immune from this tampering. This is yet another reason to stick to official apps stores for downloads.

A report from Juniper released last month claimed that mobile malware is an increasingly profit-driven business. The research firm estimates that the number of malicious mobile malware jumped 614% between March 2012 and March 2013 to account for more than 250,000 apps.

Source: http://thenextweb.com/google/2013/07/04/major-app-vulnerability-unearthed-could-affect-99-of-android-devices/

E. Coli Bacteria Has Been Experimented To Produce Biofuel

E. coli bacteria has been notorious for causing severe food poisoning. In bio-engineering field E. coli also famous of its ability to produce the long chains of carbon and hydrogen atoms found in petroleum, called fatty acids.

A research team from Harvard University's Wyss Institute, U.S.A, is on track to transform E. coli into a producer of biofuels, pharmaceuticals, plastics and just about anything else that is presently made from petroleum precursors.

According to Wyss Institute, the tough part in the research is to get E. coli to produce fatty acids that are just the right length. Long chains containing more than 12 carbons are energy-dense but too gooey. Chains that are too short don’t store enough energy and vaporize too easily. Hence, the aim is to produce chains between 4 and 12 carbons long.

An 8-carbon chain called octanoate, or caprylic acid, has been produced by altering the metabolic pathway of E. coli that converts carbon from sugar into fatty acids. Try to imagine the pathway as a river, you can visualize the chain growing longer as it flows downstream. By genetically engineering the pathway to form “dams” or tighten up, you shorten the process and therefore, shorten the length of the chain.

Caprylic acid only gets you part of the way to biofuel, though. The team is now working on a process to convert octanoate to alcohols, which is just one chemical step away from octane.

Source: http://cleantechnica.com/2013/07/03/bacteria-biofuel-gets-a-boost-from-harvard-researchers/