Ultrasensitive gas sensors based on the infusion of boron atoms into graphene—a tightly bound matrix of carbon atoms—may soon be possible, according to an international team of researchers from six countries.
University of Tokyo develops unbreakable glass that could revolutionise construction, manufacturing and dinner parties.
South Korean scientists develop an electronic skin that uses a layer of graphene film to detect sound and temperature.
A team led by materials scientist at the Ulsan National Institute of Science and Technology in South Korea has developed rubbery plastic-and-graphene film that mimics the structure of human skin. The team claims that the film can accurately detect texture, temperature, pressure and sound. This marks the first time that an electronic skin has been able to demonstrate the ability to sense the entire spectrum of stimuli, and the team is hopeful that this technology can create practical artificial skin.
Most science starts off at the fringe and slowly makes it way to the mainstream. Cryopreservation is commonly achieved in a laboratory setting, but for many years serious applications remained confined to science fiction. Is it time to change how we see cryonics?
The science of freezing things
Scientific research requires great storage, and huge amounts of material including cells are frozen every day to be used at the later date. If you follow the correct protocols, many forms of life can be re-awakened after their cryogenic sleep. DMSO, propylene glycol and glycerol help abolish problems like ice crystals which can rupture cells, and storage temperatures can drop to below −120 °C. At these levels biological reactions are essentially halted.
A team of researchers with Ulsan National Institute of Science and Technology and Dong-A University, both in South Korea, has developed an artificial skin that can detect both pressure and heat with a high degree of sensitivity, at the same time. In their paper published in the journal Science Advances, the team describes how they created the skin, what they found in testing it and the other types of things it can sense.
Many scientists around the world are working to develop artificial skin, both to benefit robots and human beings who have lost skin sensation or limbs. Such efforts have led to a wide variety of artificial skin types, but until now, none of them have been able to sense both pressure and heat to a high degree, at the same time.
The new artificial skin is a sandwich of materials; at the top there is a flexible surface meant to mimic the human fingerprint (it can sense texture), beneath that sit sensors sandwiched between graphene sheets. The sensors are domed shaped and compress to different degrees when the skin is exposed to different amount of pressure. The compression also causes a small electrical charge to move through the skin, as does heat or sound, which is also transmitted to sensors—the more pressure, heat or sound exerted, the more charge there is—using a computer to measure the charge allows for measuring the degree of sensation “felt.” The ability to sense sound, the team notes, was a bit of a surprise—additional testing showed that the artificial skin was actually better at picking up sound than an iPhone microphone.
Can black phosphorous rival #graphene?
A new experimental revelation about black phosphorus nanoribbons should facilitate the future application of this highly promising material to electronic, optoelectronic and thermoelectric devices. A team of researchers at the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) has experimentally confirmed strong in-plane anisotropy in thermal conductivity, up to a factor of two, along the zigzag and armchair directions of single-crystal black phosphorous nanoribbons.
“Imagine the lattice of black phosphorous as a two-dimensional network of balls connected with springs, in which the network is softer along one direction of the plane than another,” says Junqiao Wu, a physicist who holds joint appointments with Berkeley Lab’s Materials Sciences Division and the University of California (UC) Berkeley’s Department of Materials Science and Engineering. “Our study shows that in a similar manner heat flow in the black phosphorous nanoribbons can be very different along different directions in the plane. This thermal conductivity anisotropy has been predicted recently for 2D black phosphorous crystals by theorists but never before observed.”
Continue reading “Is black phosphorous the next big thing in materials?” »
A new approach developed by researchers at the University of Waterloo could hold the key to greatly improving the performance of commercial lithium-ion batteries. The scientists have developed a new type of silicon anode that would be used in place of a conventional graphite anode, which they claim will lead to smaller, lighter and longer-lasting batteries for everything from personal devices to electric vehicles.
Graphite has served the lithium-ion battery world as material for negative electrodes well so far, but also presents something of a roadblock for improved capacity. This is due to the relatively small amount of energy it can store, which comes in at around 370 mAh/g (milliamp hours per gram). Silicon has become an increasingly popular substitute for battery researchers looking to up the ante, with a specific capacity of 4,200 mAh/g. However, it isn’t without its limitations either.
As silicon interacts with lithium inside the cell during each charge cycle, it expands and contracts by as much as as 300 percent. This immense swelling brings about cracks that diminish the battery’s performance over time, leading to short circuits and ultimately cell failure. Other recent attempts to overcome this problem have turned up battery designs that use sponge-like silicon anodes developed at the nanoscale, silicon nanowires measuring only a few microns long and ones that bring graphene and carbon nanotubes into the mix.
A team of physicists led by Caltech’s David Hsieh has discovered an unusual form of matter—not a conventional metal, insulator, or magnet, for example, but something entirely different. This phase, characterized by an unusual ordering of electrons, offers possibilities for new electronic device functionalities and could hold the solution to a long-standing mystery in condensed matter physics having to do with high-temperature superconductivity—the ability for some materials to conduct electricity without resistance, even at “high” temperatures approaching −100 degrees Celsius.
“The discovery of this phase was completely unexpected and not based on any prior theoretical prediction,” says Hsieh, an assistant professor of physics, who previously was on a team that discovered another form of matter called a topological insulator. “The whole field of electronic materials is driven by the discovery of new phases, which provide the playgrounds in which to search for new macroscopic physical properties.”
Hsieh and his colleagues describe their findings in the November issue of Nature Physics, and the paper is now available online. Liuyan Zhao, a postdoctoral scholar in Hsieh’s group, is lead author on the paper.
One of the oddest predictions of quantum theory – that a system can’t change while you’re watching it – has been confirmed in an experiment by Cornell physicists. Their work opens the door to a fundamentally new method to control and manipulate the quantum states of atoms and could lead to new kinds of sensors.
The experiments were performed in the Utracold Lab of Mukund Vengalattore, assistant professor of physics, who has established Cornell’s first program to study the physics of materials cooled to temperatures as low as .000000001 degree above absolute zero. The work is described in the Oct. 2 issue of the journal Physical Review Letters
Graduate students Yogesh Patil and Srivatsan K. Chakram created and cooled a gas of about a billion Rubidium atoms inside a vacuum chamber and suspended the mass between laser beams. In that state the atoms arrange in an orderly lattice just as they would in a crystalline solid.,But at such low temperatures, the atoms can “tunnel” from place to place in the lattice. The famous Heisenberg uncertainty principle says that the position and velocity of a particle interact. Temperature is a measure of a particle’s motion. Under extreme cold velocity is almost zero, so there is a lot of flexibility in position; when you observe them, atoms are as likely to be in one place in the lattice as another.
Coronary artery structure being 3-D bioprinted (credit: Carnegie Mellon University College of Engineering)
Carnegie Mellon scientists are creating cutting-edge technology that could one day solve the shortage of heart transplants, which are currently needed to repair damaged organs.
“We’ve been able to take MRI images of coronary arteries and 3-D images of embryonic hearts and 3-D bioprint them with unprecedented resolution and quality out of very soft materials like collagens, alginates and fibrins,” said Adam Feinberg, an associate professor of Materials Science and Engineering and Biomedical Engineering at Carnegie Mellon University.
