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LED lighting development kit focuses on plant growth

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TSMC pulls plug on solar business

TSMC pulls plug on solar business energy solar panels

Leading IC foundry Taiwan Semiconductor Manufacturing Co. Ltd. (Hsinchu, Taiwan) has announced that its 100 percent subsidiary TSMC Solar will cease manufacturing operations at the end of August 2015. TSMC said it believes its solar business is no longer viable.

The company said it would honor all product warranties and offer jobs to all the employees working at TSMC Solar in Taiwan. TSMC Solar’s wafer fab is at Central Taiwan Science Park in Taichung.

TSMC said that depite the world-class conversion efficiency of Tower Solar’s CIGS (copper indium gallium selenide) cells the company’s late entry into the market and a lack of economies of scale led to a substantial cost disadvantage. The remaining solar panel inventory will be installed at TSMC buildings and facilities.

“TSMC continues to believe that solar power is an important source of green energy and that solar module manufacturing remains a robust and growing industry, but despite six years of hard work we have not found a way to make a sustainable profit,” said Steve Tso, chairman of TSMC Solar and senior vice president of TSMC, in a statement.

TSMC made its move into LED and solar markets during the depression in 2009 when its main IC foundry business suffered a collapse and the company was looking to diversify its risk.

In January 2015 TSMC announced its decision to sell its LED-making subsidiary TSMC Solid State Lighting, to Epistar Corp. (Hsinchu, Taiwan) for about NT$825 million (about $25.8 million).

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Hexagonal silicon could be light emitter

Hexagonal silicon could be light emitter hexagonalsilicon440

Silicon naturally crystallizes in a cubic structure and is best known in this form along with its properties such as having limited optical properties due to its indirect band gap. The hope is that when formed with hexagonal structure silicon mixed with germanium will have a direct band gap which could lead to novel electro-optical properties. It could also have novel mechanical and superconductor properties.

The research team formed the hexagonal silicon by growing it epitaxially on a gallium phosphide nanowire template. The stacking of the hexagonal structure is shown by aberration-corrected imaging in transmission electron microscopy and the material is stable up to 9 GPa pressure.

The research is published in a recent issue of Nano Letters. The team plans to use the methods laid out in this paper to fabricate hexagonal versions of germanium and silicon-germanium compounds.

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“Hexagonal silicon realized.”Nano Letters. DOI: 10.1021/acs.nanolett.5b01939

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Blue LED discovery offers chemical-free food preservation alternative

The blue LEDs are most effective when operating in cold temperatures (between 4°C and 15°C) and mildly acidic conditions of around pH 4.5.

Acidic foods such as fresh-cut fruits and ready-to-eat meat can be preserved under blue LEDs in combination with chilling temperatures without requiring further chemical treatments that are commonly needed for food preservation.

The findings have been published in the Food Microbiology journal.

Bacterial cells contain light sensitive compounds that adsorb light in the visible region of the electromagnetic spectrum (400-430 nm), which is mainly blue LED light. Exposure to illumination from blue LED light can start off a process within the cells that ultimately causes the cells to die.

Existing studies on the antibacterial effect of LED illumination evaluated its efficacy by adding photosensitisers to the food samples, or by using a close distance of less than 2 cm between the bacterial suspension and LED light source. These conditions would not be viable for application on food preservation.

The NUS team, led by Assistant Professor Yuk Hyun-Gyun, from the Food Science and Technology Programme at the NUS Faculty of Science, is the first so far to show that factors such as temperature and pH levels, which are typically related to food products, can affect the antibacterial effect of LEDs.

In the study, the team placed three major foodborne pathogens – Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella Typhimurium – under blue LED illumination, and varied the pH conditions from acidic to alkaline. The team found that higher bacterial inactivation was achieved at acidic and alkaline pH conditions than when neutral. In particular, acidic conditions were more detrimental than alkaline conditions for L. monocytogenes. For E. coli O157:H7 and S. Typhimurium, alkaline conditions were most detrimental although acidic conditions were also sufficiently effective in deactivating them.

A previous study in 2013 by the same team had also looked at the effect of temperature on blue LED’s ability to deactivate bacterial cells and found the antibacterial effect to be most enhanced in chilling temperatures.

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Nanoscale light-emitting device extends visbility of objects

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In a paper published in the journal Physical Review Letters, Zongfu Yu, an assistant professor of electrical and computer engineering, and his collaborators have described a nanoscale device that surpasses previous technology in its ability to scatter light. They showed how a single nanoresonator can manipulate light to cast a large reflection. The nanoresonator’s capacity to absorb and emit light energy is such that it can make itself and, in applications, other small things appear 10,000 times as large as its physical size.

“Making an object look 10,000 times larger than its physical size has lots of implications in technologies related to light,” said Yu. “This research opens up a new way to manipulate the flow of light, and could enable new technologies in light sensing and solar energy conversion”.

The researchers realized the advance through materials innovation and an understanding of the physics of light. Much like sound, light can resonate, amplifying itself as the surrounding environment manipulates the physical properties of its wave energy. The researchers took advantage of this by creating an artificial material in which the wavelength of light is much larger than in a vacuum, which allows light waves to resonate more powerfully.

The device condenses light to a size smaller than its wavelength, meaning it can gather a lot of light energy, and then scatters the light across a large area, harnessing its output for imaging applications that make microscopic particles appear huge.

“The device makes an object super-visible by enlarging its optical appearance with this super-strong scattering effect,” explained Ming Zhou, a Ph.D. student in Yu’s group and lead author of the paper.

Much as a thin string on a guitar can absorb a large amount of acoustic energy from its surroundings and begin to vibrate in sympathy, the small optical device can receive light energy from all around and yield a surprisingly strong output. In imaging, this presents clear advantages over conventional lenses, whose light-gathering capacity is limited by direction and size.

“We are developing photodetectors based on this technology and, for example, it could be helpful for photographers wanting to shoot better quality pictures in weak light conditions,” said Yu.

Given the nanoresonator’s capacity to absorb large amounts of light energy, the technology also has potential in applications that harvest the sun’s energy with high efficiency. In addition, Yu envisions simply letting the resonator emit that energy in the form of infrared light toward the sky, which is very cold. Because the nanoresonator has a large optical cross-section that is, an ability to emit light that exceeds its physical size it can shed a lot of heat energy, making for a passive cooling system.

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Photo battery shines light on safer power

Photo battery shines light on safer power 2015 07 10 eete pb ti photobatt

Under normal indoor lighting, the battery discharged electric current and recharged within 30 seconds without an external power source. The photo battery worked for more than 100 cycles and could power a light-emitting diode.

The ‘photo battery’, which is reported in the American Chemical Society’s The Journal of Physical Chemistry C, uses light and titanium nitride for the anode.

Metal-ion batteries such as those based on lithium ions run most of today’s gadgets but take a long time to charge. The batteries can also overheat and catch fire if they are defective or damaged. These problems are often related to the unstable material used for the anode, the negative side of the battery. Musthafa Ottakam Thotiyl and colleagues from IISER have investigated ways of addressing these flaws with a novel solution.

The researchers have developed a battery with a titanium nitride photoanode that is stable and claimed to be far safer than conventional options.

Although not yet strong enough to run commercially available devices, the researchers claim the battery design marks a first step toward a more sustainable and safer battery technology.

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Calculation program speeds evaluation of lighting solution efficiency

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Evaluations can now be obtained even faster by using the ecoCALC program’s simplified version: ecoCALC light.

The entries required to perform a calculation have been reduced to a minimum, so that up to three lighting solutions can be compared on site in just a few steps. Without having to install any software, you may use ecoCALC light on your computer or, in the mobile version, directly on your tablet PC.

The costs that will be incurred for every lighting solution across its entire service life and the resulting payback times will become obvious very quickly. Not only the investment costs, but also energy consumption, maintenance costs and CO2 emissions are collected and documented. The ecoCALC light program helps customers understand at once the evaluation of a new lighting solution in terms of both quality and quantity. Integral cost calculation provides the necessary transparency for customers to be able to make a decision resulting in measurable added value.

Access to the web-based program is possible via the following link free of charge at any time. Just a few clicks are all it takes to configure and compare various lighting solutions based on existing luminaires included in Zumtobel’s online catalog.

Calculation program speeds evaluation of lighting solution efficiency 2015 07 09 eete pb uebersicht en

Fig. 1: The web-based ecoCALC light programme boasts an intuitive input screen. Prices are examples only.

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Avnet Abacus signs European distribution deal with MechaTronix

The addition of the MechaTronix thermal management range is a major step in offering a complete lighting solution from Avnet Abacus and Silica.

From its roots as a designer and manufacturer of interconnection and packaging systems for a broad range of electronics applications, MechaTronix has grown to become a preferred cooling partner to the world’s leading high-power LED manufacturers, including Bridgelux, Cree, Lumileds, Osram, Seoul and Sharp, and provides innovative thermal management products across a broad spectrum of solid-state lighting applications.

With the arrival of high-power LEDs, thermal management is now a critical factor within LED fixtures, and MechaTronix has developed a comprehensive range of off-the-shelf LED coolers for passive or active heat dissipation, including pin-fin and star heat sinks that provide highly effective cooling for LEDs as powerful as 8000 lumen.

Avnet Abacus is now stocking the MechaTronix ModuLED and IceLED cooling series, and will build on this range with new offerings from MechaTronix for professional deployment in spotlights, downlights, architectural, and utility LED applications, among others.

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Philips opens research center for LED-based city farming

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The 234m² facility, which is one of the world’s largest, will concentrate research to optimize growth recipes for leafy vegetables, strawberries and herbs. Other areas of research will find ways to grow more carbohydrate-rich crops, like wheat and potatoes indoors.

“Our aim is to develop the technology that makes it possible to grow tasty, healthy and sustainable food virtually anywhere. The research we are undertaking will enable local food production on a global scale, reducing waste, limiting food miles and using practically no land or water,” said Gus van der Feltz, Philips Global Director of City Farming. “This new GrowWise City Farming research center aims to take City Farming to the next level, with Philips scientists leading research into LED light recipes for vegetable and cereal production.”

The research centre is a clean and sterile environment totally closed to natural light and air that enables fully controlled growing conditions. The facility uses connected LED systems that are fully customizable, allowing for the development of ‘growth recipes’ tailored to each crop variety or producers’ requirements. The end result is better tasting products, grown in a more sustainable way and without the need for pesticides.

The Philips GrowWise City Farming research center addresses a number of trends and concerns in society. There is increasing awareness of how the food we eat is grown, the effect it has on our planet and the distance it travels from farm to fork. In addition, it is anticipated that new ways of food production are needed to meet the increasing pressure on worlds’ food supply.

UN research predicts that by 2050, the world’s population will have grown by another 2.3 billion and 66% of the world’s population will inhabit cities. Meanwhile, 80% of the world’s agriculture appropriate land is already in use. Philips believes that the time is right for the innovation of new farming technologies that allow plants and crops to grow without sunlight in indoor environments close to or within cities. Philips has equipped a number of city farms such as the GreenSense in Chicago.

The Philips GrowWise City Farming research center will be a scientific testing ground that could fulfil the need of the customers in having healthy, locally produced and safe fresh produce available. The research center will unearth the lighting and technological innovations to bring farm and fork to within a few miles of each other. In addition, it will enable high quality vegetables to be harvested year round, using a fraction of the water, energy and land required for conventional farming.

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