Posts belonging to Category Materials



Green Solar Panels And Other Colors

Researchers from AMOLF, the University of Amsterdam (UvA) and the Energy Research Centre of the Netherlands (ECN) have developed a technology to create efficient bright green colored solar panels. Arrays of silicon nanoparticles integrated in the front module glass of a silicon heterojunction solar cell scatter a narrow band of the solar spectrum and create a green appearance for a wide range of angles. The remainder of the solar spectrum is efficiently coupled into the solar cell. The current generated by the solar panel is only  reduced by 10%. The realization of efficient colorful solar panels is an important step for the integration of solar panels into the built environment and landscape.
Photovoltaic
research has much focused on maximizing the electricity yield obtained from solar panels: nowadays, commercial panels have a maximum conversion efficiency from sunlight into electricity of around 22%. To reach such high efficiency, silicon solar cells have been equipped with a textured surface with an antireflection layer to absorb as much light as possible. This creates a dark blue or black appearance of the solar panels.

To create the colored solar panels the researchers have used the effect of Mie scattering, the resonant backscattering of light with a particular color by nanoparticles. They integrated dense arrays of silicon nanocylinders with a diameter of 100 nm in the top module cover slide of a high-efficiency silicon heterojunction solar cell. Due to the resonant nature of the light scattering effect, only the green part of the spectrum is reflected; the other colors are fully coupled into the solar cell. The current generated by the mini solar panel (0,7 x 0,7 cm2)  is only reduced by 10%. The solar panel appears green over a broad range of angles up to 75 degrees. The nanoparticles are fabricated using soft-imprint lithography, a technique that can readily be scaled up to large-area fabrication.
The light scattering effect due to Mie resonances is easily controllable: by changing the size of the nanoparticles the wavelength of the resonant light scattering can be tuned. Following this principle the researchers are now working to realize solar cells in other colors, and on a combination of different colors to create solar panels with a white appearance. For the large-scale application of solar panels, it is essential that their color can be tailored.

The new design was published online in the journal Applied Physics Letters.

Source: https://amolf.nl/

Chinese Quantum Satellite Sends ‘Unbreakable’ Code

China has sent an “unbreakablecode from a satellite to the Earth, marking the first time space-to-ground quantum key distribution technology has been realized, state media said. China launched the world’s first quantum satellite last August, to help establish “hack proofcommunications, a development the Pentagon has called a “notable advance“. The official Xinhua news agency said the latest experiment was published in the journal Nature, where reviewers called it a “milestone“.

The satellite sent quantum keys to ground stations in China between 645 km (400 miles) and 1,200 km (745 miles) away at a transmission rate up to 20 orders of magnitude more efficient than an optical fiber, Xinhua cited Pan Jianwei, lead scientist on the experiment from the state-run Chinese Academy of Sciences, as saying.

That, for instance, can meet the demand of making an absolute safe phone call or transmitting a large amount of bank data,” Pan said. Any attempt to eavesdrop on the quantum channel would introduce detectable disturbances to the system, Pan said. “Once intercepted or measured, the quantum state of the key will change, and the information being intercepted will self-destruct,” Xinhua said.

The news agency said there were “enormous prospects” for applying this new generation of communications in defense and finance.

Source: http://www.reuters.com/

Biodegradable Car

TU/Ecomotive (Netherlands) says ‘Lina‘ is the world’s first car with a fully biocomposite body structure. The 4-seat e-car‘s chassis uses a combination of bio-composite and bio-plastic made from sugarbeet.

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It’s made of flax, the outside is made of flax fibres, together with polypropylene. It’s pressed and heated to make flat panels. In the middle you can see polylactic acid, the honeycomb structure of that material, which adds to the strength and weight savings of the sandwich panel. All structural parts of the car are made of this material,” says Yanic Van Riel, TU/Ecomotive.

The biocomposite has a similar strength-weight ratio to fibreglass, making the car light, greatly reducing battery size.

The car weighs only 310 kilograms which is really light for a car. That’s why we only need 30 kilograms of batteries. And on those 30 kilograms of battery packs we can drive around 100 kilometres, which is about four times more efficient than a BMW i3 right now and that’s in real city driving, so braking, stopping, accelerating, not just like the most optimal driving,” explains Yanic Van Riel.

Lina has a top speed of around 50 miles per hour. Electronic features include NFCnearfield communication technology.  “We can open our doors with NFC technology and a car will immediately recognise who is driving it. So if I’m opening it, it will save all the data from me and if someone else opens it, it will save his data. In that way we can use this car for carsharing apps, which other companies are creating. Also we have a hood system which projects the speed and all the information of the car into the front window, so we can see it through the window and still see the road, so it’s more safe,” adds Noud Van De Gevel, TU/Ecomotive.

The team hopes the prototype will soon be declared roadworthy, allowing it to be tested on Eindhoven city streets.

Source: http://tuecomotive.nl/

Pilotless Cargo Flights By 2025

Pilotless planes would save airlines $35bn (£27bn) a year and could lead to substantial fare cuts – if passengers were able to stomach the idea of remote-controlled flying, according to new research. The savings for carriers could be huge, said investment bank UBS, even though it may take until the middle of the century for passengers to have enough confidence to board a pilotless plane. UBS estimated that pilots cost the industry $31bn a year, plus another $3bn in training, and that fully automated planes would fly more efficiently, saving another $1bn a year in fuel.

Passengers could benefit from a reduction in ticket prices of about a tenth, the report said. “The average percentage of total cost and average benefit that could be passed onto passengers in price reduction for the US airlines is 11%,” it said, although the savings in Europe would be less, at 4% on average but rising to 8% at RyanairAircraft costs and fuel make up a much larger proportion of costs at airlines than pilot salaries, but UBS said profits at some major airlines could double if they switched to pilotless.

More than half of the 8,000 people UBS surveyed, however, said they would refuse to travel in a pilotless plane, even if fares were cut. “Some 54% of respondents said they were unlikely to take a pilotless flight, while only 17% said they would likely undertake a pilotless flight. Perhaps surprisingly, half of the respondents said that they would not buy the pilotless flight ticket even if it was cheaper,” the report said. It added, however, that younger and more educated respondents were more willing to fly on a pilotless plane. “This bodes well for the technology as the population ages,” it said.

Source: https://www.theguardian.com/

No More Batteries For Cellphones

University of Washington (UW) researchers have invented a cellphone that requires no batteries — a major leap forward in moving beyond chargers, cords and dying phones. Instead, the phone harvests the few microwatts of power it requires from either ambient radio signals or light.

The team also made Skype calls using its battery-free phone, demonstrating that the prototype made of commercial, off-the-shelf components can receive and transmit speech and communicate with a base station.

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We’ve built what we believe is the first functioning cellphone that consumes almost zero power,” said co-author Shyam Gollakota, an associate professor in the Paul G. Allen School of Computer Science & Engineering at the UW. “To achieve the really, really low power consumption that you need to run a phone by harvesting energy from the environment, we had to fundamentally rethink how these devices are designed.”

The team of UW computer scientists and electrical engineers eliminated a power-hungry step in most modern cellular transmissionsconverting analog signals that convey sound into digital data that a phone can understand. This process consumes so much energy that it’s been impossible to design a phone that can rely on ambient power sources. Instead, the battery-free cellphone takes advantage of tiny vibrations in a phone’s microphone or speaker that occur when a person is talking into a phone or listening to a call.

An antenna connected to those components converts that motion into changes in standard analog radio signal emitted by a cellular base station. This process essentially encodes speech patterns in reflected radio signals in a way that uses almost no power. To transmit speech, the phone uses vibrations from the device’s microphone to encode speech patterns in the reflected signals. To receive speech, it converts encoded radio signals into sound vibrations that that are picked up by the phone’s speaker. In the prototype device, the user presses a button to switch between these two “transmitting” and “listening” modes.

The new technology is detailed in a paper published July 1 in the Proceedings of the Association for Computing Machinery on Interactive, Mobile, Wearable and Ubiquitous Technologies.

Source: http://www.washington.edu/
AND
http://www.reuters.com/

Hyperloop, Train Of The Future, Nearly Hits 200 mph

After announcing “the successful completion of the world’s first full systems Hyperloop test in a vacuum environment” last month, Hyperloop One is now releasing the details of a new test with their actual pod in their vacuum test tube.

They achieved a new top speed of 192 mph (310 km an hour).

Shervin Pishevar, Executive Chairman and Co-founder of Hyperloop One, made the announcement

This is the beginning, and the dawn of a new era of transportation. We’ve reached historic speeds of 310 km an hour, and we’re excited to finally show the world the XP-1 going into the Hyperloop One tube. When you hear the sound of the Hyperloop One, you hear the sound of the future.”

It’s still not on par with the ~700 mph speed that they originally planned the system to enable, but the full-scale 500-meter test track is shorter than the previously announced 1-mile long tube and it is still early in their development process.

They achieved the new top speed on just 300 meters of propulsion ramp, which is impressive, and they increased the speed by 2.7x over last month’s first test. The company disclosed that “all components of the system were successfully tested, including the highly efficient electric motor, advanced controls and power electronics, custom magnetic levitation and guidance, pod suspension and vacuum system.”

Source: https://hyperloop-one.com/
AND
https://electrek.co/

By 2025 Renewables Will Power 67 Percent Of South Australia

Declining renewables and energy storage costs will increasingly squeeze out gas-fired generation in South Australia as early as 2025, a joint research report conducted by Wood Mackenzie and GTM Research shows. The South Australia experience is noteworthy in a global power mix set to increasingly shift to renewable energy. South Australia retired its last coal plant in 2016 and is projected to have installed renewable energy capacity exceed its peak demand by 2020.

By 2025, wind, solar and battery costs will fall by 15 percent, 25 percent and 50 percent respectively. By then, renewables and batteries could offer a lower cost alternative to combined-cycle gas turbine plants, which are commonly used to manage base load power generation in South Australia. Meanwhile by 2035, renewables and batteries will provide a commercial solution for both base loads and peak loads. As a consequence, gas will increasingly be used just for emergency back-up.

One determining factor is the rate with which battery charging costs declines. By 2025, we expect battery charging cost to decrease as off-peak prices will gradually be set by excess wind generation. Battery storage then becomes a potential solution for managing peak loads,” said Bikal Pokharel, principal analyst for Wood Mackenzie‘s Asia-Pacific power and renewables .
By 2025 it’s expected that 67 percent of South Australia’s power capacity will come from renewables. Gas demand in the power sector will then decline by 70 percent.

Currently, South Australia’s peak loads are managed by open-cycle gas turbine (OCGT) plants. But by 2025, battery storage would be cheaper than OCGTs in managing peak loads even at gas price of A$7/mmbtu. OCGTs would then be relegated as emergency back-ups.”

Source: https://www.woodmac.com/

Cheap, Robust Catalyst Splits Water Into Hydrogen And Oxygen

Splitting water into hydrogen and oxygen to produce clean energy can be simplified with a single catalyst developed by scientists at Rice University and the University of Houston. The electrolytic film produced at Rice and tested at Houston is a three-layer structure of nickel, graphene and a compound of iron, manganese and phosphorus. The foamy nickel gives the film a large surface, the conductive graphene protects the nickel from degrading and the metal phosphide carries out the reactionRice chemist Kenton Whitmire and Houston electrical and computer engineer Jiming Bao and their labs developed the film to overcome barriers that usually make a catalyst good for producing either oxygen or hydrogen, but not both simultaneously.

A catalyst developed by Rice University and the University of Houston splits water into hydrogen and oxygen without the need for expensive metals like platinum. This electron microscope image shows nickel foam coated with graphene and then the catalytic surface of iron, manganese and phosphorus

Regular metals sometimes oxidize during catalysis,” Whitmire said. “Normally, a hydrogen evolution reaction is done in acid and an oxygen evolution reaction is done in base. We have one material that is stable whether it’s in an acidic or basic solution.

The discovery builds upon the researchers’ creation of a simple oxygen-evolution catalyst revealed earlier this year. In that work, the team grew a catalyst directly on a semiconducting nanorod array that turned sunlight into energy for solar water splittingElectrocatalysis requires two catalysts, a cathode and an anode. When placed in water and charged, hydrogen will form at one electrode and oxygen at the other, and these gases are captured. But the process generally requires costly metals to operate as efficiently as the Rice team’s catalyst.

The standard for hydrogen evolution is platinum,” Whitmire explained. “We’re using Earth-abundant materials — iron, manganese and phosphorus — as opposed to noble metals that are much more expensive.

The robust material is the subject of a paper in Nano Energy.

Source: http://news.rice.edu/

Move And Produce Electricity To Power Your Phone

Imagine slipping into a jacket, shirt or skirt that powers your cell phone, fitness tracker and other personal electronic devices as you walk, wave and even when you are sitting down. A new, ultrathin energy harvesting system developed at Vanderbilt University’s Nanomaterials and Energy Devices Laboratory has the potential to do just that. Based on battery technology and made from layers of black phosphorus that are only a few atoms thick, the new device generates small amounts of electricity when it is bent or pressed even at the extremely low frequencies characteristic of human motion.

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In the future, I expect that we will all become charging depots for our personal devices by pulling energy directly from our motions and the environment,” said Assistant Professor of Mechanical Engineering Cary Pint, who directed the research.
This is timely and exciting research given the growth of wearable devices such as exoskeletons and smart clothing, which could potentially benefit from Dr. Pint’s advances in materials and energy harvesting,” observed Karl Zelik, assistant professor of mechanical and biomedical engineering at Vanderbilt, an expert on the biomechanics of locomotion who did not participate in the device’s development.

Doctoral students Nitin Muralidharan and Mengya Lic o-led the effort to make and test the devices. When you look at Usain Bolt, you see the fastest man on Earth. When I look at him, I see a machine working at 5 Hertz, said Muralidharan.

The new energy harvesting system is described in a paper titled “Ultralow Frequency Electrochemical Mechanical Strain Energy Harvester using 2D Black Phosphorus Nanosheets” published  by the journal ACS Energy Letters.

Source: https://news.vanderbilt.edu/

SuperPowerful Tiny Device Converts Light Into Electricity

In today’s increasingly powerful electronics, tiny materials are a must as manufacturers seek to increase performance without adding bulk. Smaller also is better for optoelectronic devices — like camera sensors or solar cells —which collect light and convert it to electrical energy. Think, for example, about reducing the size and weight of a series of solar panels, producing a higher-quality photo in low lighting conditions, or even transmitting data more quickly.

However, two major challenges have stood in the way: First, shrinking the size of conventionally used “amorphousthin-film materials also reduces their quality. And second, when ultrathin materials become too thin, they are almost transparent — and actually lose some ability to gather or absorb light.

Now, in a nanoscale photodetector that combines both a unique fabrication method and light-trapping structures, a team of engineers from the University at Buffalo (UB) and the University of Wisconsin-Madison (UW-Madison) has overcome both of those obstacles. The researchers — electrical engineers Qiaoqiang Gan at UB, and Zhenqiang (Jack) Ma and Zongfu Yu at UW-Madison — described their device, a single-crystalline germanium nanomembrane photodetector on a nanocavity substrate, in the July 7, 2017, issue of the journal Science Advances.

This image shows the different layers of the nanoscale photodetector, including germanium (red) in between layers of gold or aluminum (yellow) and aluminum oxide (purple). The bottom layer is a silver substrate

We’ve created an exceptionally small and extraordinarily powerful device that converts light into energy,” says Gan, associate professor of electrical engineering in UB’s School of Engineering and Applied Sciences, and one of the paper’s lead authors. “The potential applications are exciting because it could be used to produce everything from more efficient solar panels to more powerful optical fibers.”

The idea, basically, is you want to use a very thin material to realize the same function of devices in which you need to use a very thick material,” says Ma, the Lynn H. Matthias Professor and Vilas Distinguished Achievement Professor in electrical and computer engineering at UW-Madison, also a lead author. Nanocavities are made up of an orderly series of tiny, interconnected molecules that essentially reflect, or circulate, light.

The new device is an advancement of Gan’s work developing nanocavities that increase the amount of light that thin semiconducting materials like germanium can absorb. It consists of nanocavities sandwiched between a top layer of ultrathin single-crystal germanium and a bottom, reflecting layer of silver.

Source: https://www.buffalo.edu/

How To Strengthen 3-D Printed Parts

From aerospace and defense to digital dentistry and medical devices, 3-D printed parts are used in a variety of industries. Currently, 3-D printed parts are very fragile and traditionally used in the prototyping phase of materials or as a toy for display. A doctoral student in the Department of Materials Science and Engineering at Texas A&M University has pioneered a countermeasure to transform the landscape of 3-D printing today.

Brandon Sweeney and his advisor Dr. Micah Green, associate professor in the Department of Chemical Engineering, discovered a way to make 3-D printed parts stronger and immediately useful in real-world applications. Sweeney and Green applied the traditional welding concepts to bond the submillimeter layers in a 3-D printed part together, while in a microwave.

I was able to see the amazing potential of the technology, such as the way it sped up our manufacturing times and enabled our CAD designs to come to life in a matter of hours,” Sweeney said. “Unfortunately, we always knew those parts were not really strong enough to survive in a real-world application.

3-D printed objects are comprised of many thin layers of materials, plastics in this case, deposited on top of each other to form a desired shape. These layers are prone to fracturing, causing issues with the durability and reliability of the part when used in a real-world application, for example a custom printed medical device. “I knew that nearly the entire industry was facing this problem,” Sweeney said. “Currently, prototype parts can be 3-D printed to see if something will fit in a certain design, but they cannot actually be used for a purpose beyond that.”

When Sweeney started his doctorate, he was working with Green in the Department of Chemical Engineering at Texas Tech University. Green had been collaborating with Dr. Mohammad Saed, assistant professor in the electrical and computer engineering department at Texas Tech, on a project to detect carbon nanotubes using microwaves. The trio crafted an idea to use carbon nanotubes in 3-D printed parts, coupled with microwave energy to weld the layers of parts together.

The basic idea is that a 3-D part cannot simply be stuck into an oven to weld it together because it is plastic and will melt,” Sweeney said. “We realized that we needed to borrow from the concepts that are traditionally used for welding parts together where you’d use a point source of heat, like a torch or a TIG welder to join the interface of the parts together. You’re not melting the entire part, just putting the heat where you need it.” The technology is patent-pending and licensed with a local company, Essentium Materials.

The team recently published a paper “Welding of 3-D Printed Carbon Nanotube-Polymer Composites by Locally Induced Microwave Heating,” in Science Advances.

Source: http://engineering.tamu.edu/

Sion, The Solar-Powered Car

What has room for 6 passengers, an all-electric range of up to 155 miles (250 kilometers), and a body covered in solar panels that can add as many as 18 miles (30 kilometers) of driving a day from sunlight? That would be the Sono Motors Sion, an innovative solar-powered car from a team of German entrepreneurs that is scheduled to have its world debut on July 27 (2017).

The Sion project was able to move forward thanks to an Indiegogo crowdfunding campaign last year that raised over a half million dollars. More than 1,000 people have participated so far.

The car will have two versions. The Urban comes with a 14.4 kilowatt-hour battery pack. It has a range of about 75 miles (121 kilometers) and will cost $13,200. The Extender version has a 30 kilowatt-hour battery and a range of 155 miles (250 kilometers). Its target price is $17,600. Neither price includes the battery. Like the Renault Zoe, customers will either buy the battery separately or lease it. The leasing option gives owners the flexibility to upgrade the battery later as improvements in battery technology become available.

The hood, roof, and rear hatch of the Sion are covered with monocrystalline silicon cells that are 21% efficient. On a sunny day, they can generate enough electricity to add 18 miles of range. The solar cells are 8 millimeters thick and embedded in a polycarbonate layer that is shatterproof, weather resistant, and light in weight. The Sion can also be 80% charged using an AC outlet in about 30 minutes, according to company claims. No DC charging option is available. The car also comes with an outlet that can power electronic devices.

Inside, all the seats of the 5 door hatchback fold flat, offering multiple configurations for carrying passengers and cargo. There is a 10 inch center display and smartphone connectivity via WiFi or Bluetooth. The ventilation system is called breSono and incorporates a dollop of moss, which is said to act as a natural filter when an electrical charge is applied.

The company will offer an online maintenance and repair system it calls reSono. It allows owners to order parts online and comes with a video that shows them how to install the parts when they arrive.  Or they can take the car and the parts to any local auto repair shop facility to get them installed.

Source: https://www.sonomotors.com/
AND
https://cleantechnica.com/