Posts belonging to Category green power

Car Waste Heat Transformed Into Electricity

Thermoelectric materials can turn a temperature difference into an electric voltage. Among their uses in a variety of specialized applications: generating power on space probes and cooling seats in fancy cars.

University of Miami physicist Joshua Cohn and his collaborators report new surprising properties of a metal named lithium purple-bronze (LiPB) that may impact the search for materials useful in power generation, refrigeration, or energy detection.

If current efficiencies of thermoelectric materials were doubled, thermoelectric coolers might replace the conventional gas refrigerators in your home,” said Cohn, professor and chairman of the UM Department of Physics in the College of Arts and Sciences and lead author of the study. “Converting waste heat into electric power, for example, using vehicle exhaust, is a near-termgreen’ application of such materials.”
The findings are published in the journal Physical Review Letters.


World’s Smallest, Fastest Nanomotor

Researchers at the Cockrell School of Engineering at The University of Texas at Austin have built the smallest, fastest and longest-running tiny synthetic motor to date. The team’s nanomotor is an important step toward developing miniature machines that could one day move through the body to administer insulin for diabetics when needed, or target and treat cancer cells without harming good cells.

With the goal of powering these yet-to-be invented devices, UT Austin engineers focused on building a reliable, ultra-high-speed nanomotor that can convert electrical energy into mechanical motion on a scale 500 times smaller than a grain of salt.

Mechanical engineering assistant professor Donglei “Emma” Fan led a team of researchers in the successful design, assembly and testing of a high-performing nanomotor in a nonbiological setting. The team’s three-part nanomotor can rapidly mix and pump biochemicals and move through liquids, which is important for future applications. One amazing arena of application for this nanomotor is the field of nanoelectromechanical systems (NEMS), where such a machine will be able to push forward the frontiers of cheaper and more energy efficient systems.
The team’s study was published in the April issue of Nature Communications.


Lithium-Ion Batteries That Last 3 Times Longer

Using a material found in Silly Putty and surgical tubing, a group of researchers at the University of California, Riverside Bourns College of Engineering have developed a new way to make lithium-ion batteries that will last three times longer between charges compared to the current industry standard.
The team created silicon dioxide (SiO2) nanotube anodes for lithium-ion batteries and found they had over three times as much energy storage capacity as the carbon-based anodes currently being used. This has significant implications for industries including electronics and electric vehicles, which are always trying to squeeze longer discharges out of batteries.

We are taking the same material used in kids’ toys and medical devices and even fast food and using it to create next generation battery materials,” said Zachary Favors, the lead author of a just-published paper online in the journal Nature Scientific Reports.


NanoFiber Mask Against Lethal Diesel Pollution

When a silver grey haze descends upon Hong Kong in springtime, would you wonder if it is harmful to your lungs? Haze is usually composed of pollutants in the form of tiny suspended particles or fine mists/droplets emitted from vehicles, coal-burning power plants and factories. Continued exposure increases the risk of developing respiratory problems, heart diseases and lung cancer. Can we avoid the unhealthy air? A simple face mask which can block out suspended particles has been developed by scientists from the Department of Mechanical Engineering at The Hong Kong Polytechnic University (PolyU). The project is led by Professor Wallace Woon-Fong Leung, a renowned filtration expert, who has spent his career understanding these invisible killers.

In Hong Kong, suspended particles PM 10 and PM 2.5 are being monitored. PM 10 refers to particles that are 10 microns (or micrometres) in size or smaller, whereas PM 2.5 measures 2.5 microns or smaller.

The nanofibre filter can capture diesel dust effectively
In my view, nano-aerosols (colloid of fine solid particles or liquid droplets of sub-micron to nano-sizes), such as diesel emissions, are the most lethal for three reasons. First, they are in their abundance by number suspended in the air. Second, they are too small to be filtered out using current technologies. Third, they can pass easily through our lungs and work their way into our respiratory systems, and subsequently our vascular, nervous and lymphatic systems, doing the worst kind of harm”, said Professor Leung, At the forefront of combating air pollution. Leung targets ultra-fine pollutants that have yet been picked up by air quality monitors – particles measuring 1 micron or below, which he perceived to be a more important threat to human health.


Smartphones Printed On T-shirts

A new version of “spaser” technology being investigated could mean that mobile phones become so small, efficient, and flexible they could be printed on clothing.
A team of researchers from Monash University – Australia – Department of Electrical and Computer Systems Engineering (ECSE) has modelled the world’s first spaser (surface plasmon amplification by stimulated emission of radiation) to be made completely of carbon.
A spaser is effectively a nanoscale laser or nanolaser. It emits a beam of light through the vibration of free electrons, rather than the space-consuming electromagnetic wave emission process of a traditional laser.
PhD student and lead researcher Chanaka Rupasinghe said the modelled spaser design using carbon would offer many advantages.

Other spasers designed to date are made of gold or silver nanoparticles and semiconductor quantum dots while our device would be comprised of a graphene resonator and a carbon nanotube gain element,” Chanaka said.
The use of carbon means our spaser would be more robust and flexible, would operate at high temperatures, and be eco-friendly.
Because of these properties, there is the possibility that in the future an extremely thin mobile phone could be printed on clothing.”


How To Heat Your House At Night With Sun’s Energy

It’s an obvious truism, but one that may soon be outdated: The problem with solar power is that sometimes the sun doesn’t shine. Now a team at the Massachusetts Institute of Technology ( MIT) and Harvard University has come up with an ingenious workaround — a material that can absorb the sun’s heat and store that energy in chemical form, ready to be released again on demand. This solution is no solar-energy panacea: While it could produce electricity, it would be inefficient at doing so. But for applications where heat is the desired output — whether for heating buildings, cooking, or powering heat-based industrial processes — this could provide an opportunity for the expansion of solar power into new realms.

It could change the game, since it makes the sun’s energy, in the form of heat, storable and distributable,” says Jeffrey Grossman, the Carl Richard Soderberg Associate Professor of Power Engineering at MIT, who is a co-author of a paper describing the new process in the journal Nature Chemistry. Timothy Kucharski, a postdoc at MIT and Harvard, is the paper’s lead author.

Very Cheap, Powerful Solar Cells

Working on dye-sensitized solar cells – researchers from University Malaya (UM) – Indonesia – and National Tsing Hua University (NTHU) – Taiwan – have achieved an efficiency of 1.12 %, at a fraction of the cost compared to those used by platinum devices.
The study carried out in Taiwan took on the challenge of making the technology behind dye-sensitized solar cells more affordable by replacing the costly platinum counter-electrodes with bismuth telluride (Bi2Te3) nanosheet arrays.
Using a novel electrolysis process, the group managed to closely manipulate the spacing between individual nanosheets and hence control the thermal and electrical conductivity parameters to achieve the high efficiency of 1.12%, which is comparable to platinum devices, but at only at a fraction of the cost.
The research was led by Prof. Yu-Lun Chueh of the Nanoscience & Nanodevices Laboratory, NTHU, and Alireza Yaghoubi, UM HIR Young Scientist.

In light of the recent report by the United Nations about the irreversible effects of fossil fuels on climate change and as we gradually run out of economically recoverable oil reserves, we think it is necessary to look for a sustainable, yet practical source of energy” Yaghoubi stated.
Meanwhile at University Malaya, Dr. Wee Siong Chiu and colleagues were working on controlling the secondary nucleation and self-assembly in zinc oxide (ZnO), a material which is currently being scrutinized for its potential applications in dye-sensitized solar cells as well as photocatalytic reactions to generate clean electricity by splitting water under sunlight.
This work has been accepted for publication in the journal, Nanoscale published by the Royal Society of Chemistry and has been selected for the front cover of the issue.

Super Powerful Batteries To Extend Electric Car Range

Electric vehicles could travel farther and more renewable energy could be stored with lithium-sulfur batteries that use a unique powdery nanomaterial.
Researchers from The Department of Energy’s Pacific Northwest National Laboratory added the powder, a kind of nanomaterial called a metal organic framework, to the battery’s cathode to capture problematic polysulfides that usually cause lithium-sulfur batteries to fail after a few charges.

Lithium-sulfur batteries have the potential to power tomorrow’s electric vehicles, but they need to last longer after each charge and be able to be repeatedly recharged,” said materials chemist Jie Xiao of the Department of Energy’s Pacific Northwest National Laboratory. “Our metal organic framework may offer a new way to make that happen.
Today’s electric vehicles are typically powered by lithium-ion batteries. But the chemistry of lithium-ion batteries limits how much energy they can store. As a result, electric vehicle drivers are often anxious about how far they can go before needing to charge. One promising solution is the lithium-sulfur battery, which can hold as much as four times more energy per mass than lithium-ion batteries. This would enable electric vehicles to drive farther on a single charge, as well as help store more renewable energy. The down side of lithium-sulfur batteries, however, is they have a much shorter lifespan because they can’t currently be charged as many times as lithium-ion batteries.

A paper describing the material and its performance was published online April 4 in the American Chemical Society journal Nano Letters.

You Will Wear Clothes Made From Sugar

In the future, the clothes you wear could be made from sugar. Researchers at the A*STAR Institute of Bioengineering and Nanotechnology (IBN) – Singapore – have discovered a new chemical process that can convert adipic acid directly from sugar. Adipic acid is an important chemical used to produce nylon for apparel and other everyday products like carpets, ropes and toothbrush bristles. Commercially, adipic acid is produced from petroleum-based chemicals through the nitric acid oxidation process, which emits large amounts of nitrous oxides, a major greenhouse gas that causes global warming.

In the face of growing environmental concerns over the use of fossil fuels and diminishing natural resources, there is an increasing need for a renewable source for energy and chemicals. We have designed a sustainable and environmentally friendly solution to convert sugar into adipic acid via our patented catalytic process technology,”said IBN Executive Director Professor Jackie Y. Ying

Bio-based adipic acid can be synthesized from mucic acid, which is oxidized from sugar; and the mucic acid can be obtained from fruit peels. Current processes are either performed using multiple steps with low product efficiency and yield, or under harsh reaction conditions using high-pressure hydrogen gas and strong acids, which are costly and unsafe.

This work shows the tremendous potential of developing bio-based adipic acid. We are excited that our new protocol can efficiently convert adipic acid from sugar, bringing us one step closer toward industrialization. To complete this green technology, we are now working on using raw biomass as the feedstock” said Dr Yugen Zhang, IBN Group Leader in green chemistry and energy.

This finding was published recently in the Chemistry journal Angewandte Chemie International Edition.


Solar Cells Used As Lasers

A relatively new type of solar cell based on a perovskite material – named for scientist Lev Perovski, who first discovered materials with this structure in the Ural Mountains in the 19th century – was recently pioneered by an Oxford research team led by Professor Henry Snaith. Commercial silicon-based solar cells – such as those seen on the roofs of houses across the country – operate at about 20% efficiency for converting the Sun’s rays into electrical energy. It’s taken over 20 years to achieve that rate of efficiency. Latest research finds that the trailblazing ‘perovskite’ material used in solar cells can double up as a laser, strongly suggesting the astonishing efficiency levels already achieved in these cells is only part of the journey. Scientists have demonstrated potential uses for this material in telecommunications and for light emitting devices.

Perovskite solar cells, the source of huge excitement in the research community, already lie just a fraction behind commercial silicon, having reached a remarkable 17% efficiency after a mere two years of research – transforming prospects for cheap large-area solar energy generation.
Now, researchers from Professor Sir Richard Friend’s group at Cambridge’s Cavendish Laboratory – working with Snaith’s Oxford group – have demonstrated that perovskite cells excel not just at absorbing light but also at emitting it. The new findings, recently published online in the Journal of Physical Chemistry Letters, show that these ‘wonder cells’ can also produce cheap lasers. By sandwiching a thin layer of the lead halide perovskite between two mirrors, the team produced an optically driven laser which proves these cells “show very efficient luminescence” – with up to 70% of absorbed light re-emitted.