Posts belonging to Category electronics

Reconfigurable Materials

Metamaterialsmaterials whose function is determined by structure, not composition — have been designed to bend light and sound, transform from soft to stiff, and even dampen seismic waves from earthquakes. But each of these functions requires a unique mechanical structure, making these materials great for specific tasks, but difficult to implement broadly. But what if a material could contain within its structure, multiple functions and easily and autonomously switch between them?

Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and the Wyss Institute of Biologically Inspired Engineering at Harvard University have developed a general framework to design reconfigurable metamaterials. The design strategy is scale independent, meaning it can be applied to everything from meter-scale architectures to reconfigurable nano-scale systems such as photonic crystals, waveguides and metamaterials to guide heat.

In terms of reconfigurable metamaterials, the design space is incredibly large and so the challenge is to come up with smart strategies to explore it,” said Katia Bertoldi, John L. Loeb Associate Professor of the Natural Sciences at SEAS and senior author of the paper. “Through a collaboration with designers and mathematicians, we found a way to generalize these rules and quickly generate a lot of interesting designs.”

The research is published in Nature.

Device Doubles The Energy Conversion Of Solar Cells

Scientists from Japan are utilizing nanotechnology advancements to strengthen solar cellsSolar cells convert light into electricity using a bevy of sources, including light from the sun and the burning of natural resources such as oil and natural gas. However, the cells do not convert all light to power equally, which led to scientists attempting to find ways to produce more power. The flame of a gas burner will shift from red to blue as the heat increases because higher temperatures emit light at shorter wavelengths. Higher heat offers more energy, making short wavelengths an important target in the design of solar cells. Kyoto University‘s Takashi Asano, began using optical technologies to improve energy production.

device to double the power of solar cells

Current solar cells are not good at converting visible light to electrical power. The best efficiency is only around 20 percent,” Asano said in a statement. “The problem is that heat dissipates light of all wavelengths, but a solar cell will only work in a narrow range. To solve this, we built a new nano-sized semiconductor that narrows the wavelength bandwidth to concentrate the energy.

The researchers were able to use their nanoscale semiconductor to raise the energy conversion rate to at least 40 percent. Asano and researchers at the Susumu Noda lab had previously attempted to work with higher wavelengths. “Our first device worked at high wavelengths but to narrow output for visible light required a new strategy, which is why we shifted to intrinsic silicon in this current collaboration with Osaka Gas,” Asano said. Visible wavelengths are emitted at 1000 degrees Celsius but conveniently silicon has a melting temperature of over 1,400 degrees Celsius.

This concept was utilized by the scientists, who etched silicon plates to have a large number of identical and equidistantly-spaced rods, the height, radii and spacing of which was optimized for the target bandwidth. Susumu Noda, a professor at Kyoto University, explained the benefits of the advancement: “Our technology has two important benefits. First is energy efficiency: we can convert heat into electricity much more efficiently than before. Secondly is design:  we can now create much smaller and more robust transducers, which will be beneficial in a wide range of applications.”

The study was published in Science Advances.


How To Fast Manafacture NanoRobots

A team of researchers led by Biomedical Engineering Professor Sam Sia at Columbia Engineering has developed a way to manufacture microscale machines from biomaterials that can safely be implanted in the body. Working with hydrogels, which are biocompatible materials that engineers have been studying for decades, Sia has invented a new technique that stacks the soft material in layers to make devices that have three-dimensional, freely moving parts. The study, published online January 4, 2017, in Science Robotics, demonstrates a fast manufacturing method Sia calls “implantable microelectromechanical systems” (iMEMS).

By exploiting the unique mechanical properties of hydrogels, the researchers developed a “locking mechanism” for precise actuation and movement of freely moving parts, which can function as valves, manifolds, rotors, pumps, and drug delivery systems. They were able to tune the biomaterials within a wide range of mechanical and diffusive properties and to control them after implantation without a sustained power supply, such as a toxic battery. They then tested the payload delivery in a bone cancer model and found that the triggering of releases of doxorubicin from the device over 10 days showed high treatment efficacy and low toxicity, at 1/10th of the standard systemic chemotherapy dose.

implantable nanorobot

Overall, our iMEMS platform enables development of biocompatible implantable microdevices with a wide range of intricate moving components that can be wirelessly controlled on demand and solves issues of device powering and biocompatibility,” says Sia, also a member of the Data Science Institute. “We’re really excited about this because we’ve been able to connect the world of biomaterials with that of complex, elaborate medical devices.  Our platform has a large number of potential applications, including the drug delivery system demonstrated in our paper which is linked to providing tailored drug doses for precision medicine.”


Electric Motorbike Round-The-World Trip

80-day round-the-world trips aren’t new – but using an electric motorbike built from scratch by students on them certainly is. Eindhoven University of Technology (Netherlands) riders drove up to 500 kilometres a day on their self-constructed Storm Wave bike, relying entirely on battery power. Other students rode behind in a bus, with one change of driver and battery swap per day.

Storm electric motorcycleCLICK ON THE IMAGE TO ENJOY THE VIDEO

With a full pack you can ride 400 kilometres on one single charge. But during our tour we had to drive more, so we had to re-energise quickly. So we just took the empty ones out, replaced them with charged ones, and we could ride again,” says Bas Verkaik, Spokeperson for Storm Eindhoven.  Key to the Storm Wave is its unique modular system of 24 individual batteries. This helped ease navigation of difficult roads in countries like Turkmenistan and Uzbekhistan.

When we faced those bad roads we just took, for example half of the batteries out, we have a lighter motorcycle, lower centre of gravity, which makes it easier to handle,” comments Bas Verkaik. Storm Wave also contains a gearbox, unusual for an electric motorcycle, but allowing greater acceleration and efficiency at high speeds.

The misconceptions people have about electric vehicles is that either they’re slow or they don’t have enough power or they can’t drive fast or far enough. With our motorcycle it can go from zero to 100 (kilometres per hour) in under five seconds, and probably could go even faster if we changed some specs… I think it looks pretty nice. That’s also a misconception that people have, that electric vehicles have to be futuristic and they don’t like the design, but I’ve only heard good things about this motorcycle” , explains Storm Wave driver Yorick Heidema.

The 23 students returned home in November after receiving huge interest in cities they drove through. They say they’ve showed the world that long-distance electric vehicle travel isn’t just feasible, but cool too.


No More Speakers For Television

Sony has created the world’s first television which can emit sound from the screen itself, removing the need for separate speakers. Unveiled at CES 2017 in Las Vegas, the A1 BRAVIA OLED series features a unique “Acoustic Surface“, which sees the sound being emitted from the whole of the screen.

Sony Bravia

Sony creates a 3D sound scape by pairing the objects you’re viewing on the screen to the sound that they are making. For example, if you were watching a movie where a car drives across the screen, the sound will follow the movement of the car, adding a whole new level of immersion to your home entertainment experience. The screen transmits sound through two transducers which are located on the back of screen. These generate vibrations onto the area of the screen that’s required to transmit the sound. Despite the BRAVIA screen working as both a screen and a speaker, it remains impressively streamline. The display also comes with clean cable management to keep wires out of view. The technology could eventually expand to include LED screens, but Sony don’t have any plans do this just yet, as the multiple layers that make up a LED screen makes it harder to retain the picture and audio quality.

By truly fusing together the image and sound, Sony’s new BRAVIA TV gives a heightened TV viewing experience without you having to set up a complex system of surround sound speakers.


How To Convert Heat Into Electricity

The same researchers who pioneered the use of a quantum mechanical effect to convert heat into electricity have figured out how to make their technique work in a form more suitable to industry. In Nature Communications, engineers from The Ohio State University (OSU) describe how they used magnetism on a composite of nickel and platinum to amplify the voltage output 10 times or more—not in a thin film, as they had done previously, but in a thicker piece of material that more closely resembles components for future electronic devices.

Many electrical and mechanical devices, such as car engines, produce heat as a byproduct of their normal operation. It’s called “waste heat,” and its existence is required by the fundamental laws of thermodynamics, explained study co-author Stephen Boona.

devices-that-convert-heat-into-electricityOver half of the energy we use is wasted and enters the atmosphere as heat,” said Boona, a postdoctoral researcher at Ohio State. “Solid-state thermoelectrics can help us recover some of that energy. These devices have no moving parts, don’t wear out, are robust and require no maintenance. Unfortunately, to date, they are also too expensive and not quite efficient enough to warrant widespread use. We’re working to change that.”But a growing area of research called solid-state thermoelectrics aims to capture that waste heat inside specially designed materials to generate power and increase overall energy efficiency.


Nanowire Inks For Printable Electronics

By suspending tiny metal nanoparticles in liquids, Duke University scientists are brewing up conductive ink-jet printer “inks” to print inexpensive, customizable circuit patterns on just about any surfacePrinted electronics, which are already being used on a wide scale in devices such as the anti-theft radio frequency identification (RFID) tags you might find on the back of new DVDs, currently have one major drawback: for the circuits to work, they first have to be heated to melt all the nanoparticles together into a single conductive wire, making it impossible to print circuits on inexpensive plastics or paper. A new study by Duke researchers shows that tweaking the shape of the nanoparticles in the ink might just eliminate the need for heat.

By comparing the conductivity of films made from different shapes of silver nanostructures, the researchers found that electrons zip through films made of silver nanowires much easier than films made from other shapes, like nanospheres or microflakes. In fact, electrons flowed so easily through the nanowire films that they could function in printed circuits without the need to melt them all together.


The nanowires had a 4,000 times higher conductivity than the more commonly used silver nanoparticles that you would find in printed antennas for RFID tags,” said Benjamin Wiley, assistant professor of chemistry at Duke. “So if you use nanowires, then you don’t have to heat the printed circuits up to such high temperature and you can use cheaper plastics or paper.”

There is really nothing else I can think of besides these silver nanowires that you can just print and it’s simply conductive, without any post-processing,” Wiley added.

These types of printed electronics could have applications far beyond solar cells; researchers envision using the technology to make solar cells, printed displays, LEDS, touchscreens, amplifiers, batteries and even some implantable bio-electronic devices. The results appeared online Dec. 16 in ACS Applied Materials and Interfaces.


DNA DataStorage, New Frontier For Nanotechnology

Nanotechnology holds a lot of promise to almost every aspect of our lives from consumer electronics to ending life-threatening illnesses. However, the greatest challenge nanotechnology is facing is the limitation of how much smaller they can shrink the physical size of semiconductors. However, a group of scientists are taking that challenge and if they are successful, we may be well on our way to a future much wilder than science fiction – molecular electronics.


Molecular electronics works at the most minute scale using single molecules including its sub properties and characteristics. The concept of molecular electronics was first originated in 1997 by Mark Reed and his colleagues.

This is what a team of Russian and Israeli scientists are trying to explore as the demand for smaller electronic devices proliferate. Their study proposes to “metallizeDNA using nanoparticles of silver.

First of all, the DNA can hold a great amount of information despite its small size. What’s more intriguing is that the ability of DNA is not limited to storing only genetic information. The study has revealed that the DNA has more uncanny and unique features.

The first feature they discovered was that the DNA has superconducting abilities when placed between two superconductors. The second feature was that they can effect charge transport, which happen when you introduce metal atoms along the strand. Moreover, the scientists also discovered that the conductivity of the DNA molecules depend on the type of substrate they are placed on.

Although the scientists were able to ‘metallize‘ atoms, the distribution was not even along the entire length of the strands, which means not all of it becomes ‘metal.’ However, they found out that these DNA molecules can interact with silver nanoparticles resulting in an even metal DNA strand.

If further experimentation and testing become successful, such nanowire would be 1.1 nanometers high and 400 nanometers long.

The study is published in Advanced Materials.


The Rise Of The Hydrogen Electric Car

Right now, if you want an alternative-fuel vehicle, you have to pick from offerings that either require gasoline or an electrical outlet. The gas-electric hybrid and the battery-powered car — your Toyota Priuses, Chevy Volts, and Teslas — are staples in this space. There are drawbacks for drivers of both types. You still have to buy gas for your hybrid and you have to plug in your Tesla — sometimes under less than favorable conditions — lest you be stranded someplace far away from a suitable plug. Beyond that, automakers have been out to find the next viable energy source. Plug-in vehicles are more or less proven to be the answer, but Toyota and a handful of other carmakers are investigating hydrogen.


That’s where the Toyota Mirai comes in. The Mirai‘s interior center stack has all the technology you would expect from a car that retails for $57,500, including navigation, Bluetooth, and USB connectivity. It’s all accessible by touch screens and robust digital displays.
A fill-up on hydrogen costs just about as much as regular gasoline in San Francisco. The Mirai gets an estimated 67 MPGe (67 Miles per gallon gasoline equivalent = 28,5 kilometers per liter)), according to Toyota.
It’s an ambitious project for Toyota because the fueling infrastructure for this car is minimal. There are only 33 public hydrogen-filling stations in the US, according to the US Department of Energy. Twenty-six of those stations are in California, and there’s one each in Connecticut, Massachusetts, and South Carolina.

If you include public and private hydrogen stations, then the total climbs to 58 — nationwide. Compare that to the more than 15,100 public electric-charging stations and the 168,000 retail gas stations in the US, and you can see the obvious drawback of hydrogen-powered cars. Despite this, the Mirai is an interesting project, and you must keep in mind that Japan at the Government level seems to bet on a massively hydrogen powered economy in the near future (fuel, heating, replacement of nuclear energy, trains, electric vehicles, etc…).


Japan Bets On Hydrogen As A Green Energy Source

Hydrogen gas is a promising alternative energy source to overcome our reliance on carbon-based fuels, and has the benefit of producing only water when it is reacted with oxygen. However, hydrogen is highly reactive and flammable, so it requires careful handling and storage. Typical hydrogen storage materials are limited by factors like water sensitivity, risk of explosion, difficulty of control of hydrogen-generation.

alstom-hydrogen-electric-train Hydrogen gas can be produced efficiently from organosilanes, some of which are suitably air-stable, non-toxic, and cheap. Catalysts that can efficiently produce hydrogen from organosilanes are therefore desired with the ultimate goal of realizing safe, inexpensive hydrogen production in high yield. Ideally, the catalyst should also operate at room temperature under aerobic conditions without the need for additional energy input. A research team led by Kiyotomi Kaneda and Takato Mitsudome at Osaka University have now developed a catalyst that realizes efficient environmentally friendly hydrogen production from organosilanes. The catalyst is composed of gold nanoparticles with a diameter of around 2 nm supported on hydroxyapatite.

The team then added the nanoparticle catalyst to solutions of different organosilanes to measure its ability to induce hydrogen production. The nanoparticle catalyst displayed the highest turnover frequency and number attained to date for hydrogen production catalysts from organosilanes. For example, the  converted 99% of dimethylphenylsilane to the corresponding silanol in just 9 min at room temperature, releasing an equimolar amount of hydrogen gas at the same time. Importantly, the catalyst was recyclable without loss of activity. On/off switching of hydrogen production was achieved using the nanoparticle catalyst because it could be easily separated from its organosilane substrate by filtration. The activity of the catalyst increased as the nanoparticle size decreased.

A prototype portable hydrogen fuel cell containing the nanoparticle catalyst and an organosilane substrate was fabricated. The fuel cell generated power in air at room temperature and could be switched on and off as desired.

Generation of hydrogen from inexpensive organosilane substrates under ambient conditions without additional energy input represents an exciting advance towards the goal of using hydrogen as a green energy source.


Graphene Detects Early Cancer

What can’t graphene do? You can scratch “detect cancer” off of that list. By interfacing brain cells onto graphene, researchers at the University of Illinois at Chicago (UIC) have shown they can differentiate a single hyperactive cancerous cell from a normal cell, pointing the way to developing a simple, noninvasive tool for early cancer diagnosis.

graphene-cancer-detectionNormal and cancerous brain cells interfaced with graphene show different activity levels under Raman imaging.
This graphene system is able to detect the level of activity of an interfaced cell,” says Vikas Berry, associate professor and head of chemical engineering at UIC, who led the research along with Ankit Mehta, assistant professor of clinical neurosurgery in the UIC College of Medicine.
The cell’s interface with graphene rearranges the charge distribution in graphene, which modifies the energy of atomic vibration as detected by Raman spectroscopy,” Berry said, referring to a powerful workhorse technique that is routinely used to study graphene. The atomic vibration energy in graphene’s crystal lattice differs depending on whether it’s in contact with a cancer cell or a normal cell, Berry said, because the cancer cell’s hyperactivity leads to a higher negative charge on its surface and the release of more protons.“Graphene is the thinnest known material and is very sensitive to whatever happens on its surface,” Berry said. The nanomaterial is composed of a single layer of carbon atoms linked in a hexagonal chicken-wire pattern, and all the atoms share a cloud of electrons moving freely about the surface.

The study, reported in the journal ACS Applied Materials & Interfaces, looked at cultured human brain cells, comparing normal astrocytes to their cancerous counterpart, the highly malignant brain tumor glioblastoma multiforme. The technique is now being studied in a mouse model of cancer, with results that are “very promising,” Berry said. “Once a patient has brain tumor surgery, we could use this technique to see if the tumor relapses,” Berry said. “For this, we would need a cell sample we could interface with graphene and look to see if cancer cells are still present.”

The same technique may also work to differentiate between other types of cells or the activity of cells. “We may be able to use it with bacteria to quickly see if the strain is Gram-positive or Gram-negative,” Berry said. “We may be able to use it to detect sickle cells.”

Earlier this year, Berry and other coworkers introduced nanoscale ripples in graphene, causing it to conduct differently in perpendicular directions, useful for electronics. They wrinkled the graphene by draping it over a string of rod-shaped bacteria, then vacuum-shrinking the germs. “We took the earlier work and sort of flipped it over,” Berry said. “Instead of laying graphene on cells, we laid cells on graphene and studied graphene’s atomic vibrations.”

Co-authors on the study are Bijentimala Keisham and Phong Nguyen of UIC chemical engineering and Arron Cole of UIC neurosurgery.


“Liquid Biopsy” Chip Detects Metastatic Cancer Cells in a Drop of Blood

A chip developed by mechanical engineers at Worcester Polytechnic Institute (WPI) can trap and identify metastatic cancer cells in a small amount of blood drawn from a cancer patient. The breakthrough technology uses a simple mechanical method that has been shown to be more effective in trapping cancer cells than the microfluidic approach employed in many existing devices.


The chip is tested in the lab. The electrodes detect electrical changes that occur when cancer cells are captured (click on the image to enjoy the video)

The WPI device uses antibodies attached to an array of carbon nanotubes at the bottom of a tiny well. Cancer cells settle to the bottom of the well, where they selectively bind to the antibodies based on their surface markers (unlike other devices, the chip can also trap tiny structures called exosomes produced by cancers cells). This “liquid biopsy,”  could become the basis of a simple lab test that could quickly detect early signs of metastasis and help physicians select treatments targeted at the specific cancer cells identified.

Metastasis is the process by which a cancer can spread from one organ to other parts of the body, typically by entering the bloodstream. Different types of tumors show a preference for specific organs and tissues; circulating breast cancer cells, for example, are likely to take root in bones, lungs, and the brain. The prognosis for metastatic cancer (also called stage IV cancer) is generally poor, so a technique that could detect these circulating tumor cells before they have a chance to form new colonies of tumors at distant sites could greatly increase a patient’s survival odds.

The focus on capturing circulating tumor cells is quite new,” said Balaji Panchapakesan, associate professor of mechanical engineering at WPI and director of the Small Systems Laboratory. “It is a very difficult challenge, not unlike looking for a needle in a haystack. There are billions of red blood cells, tens of thousands of white blood cells, and, perhaps, only a small number of tumor cells floating among them. We’ve shown how those cells can be captured with high precision.

The findings have been described in  the journal Nanotechnology,