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Archive for the ‘materials’ category: Page 293

Nov 10, 2015

Next Big Future: Superconducting at −70 degrees celsius seems to be accepted

Posted by in categories: chemistry, materials, physics

The world of superconductivity is in uproar. Last year, Mikhail Eremets and a couple of pals from the Max Planck Institute for Chemistry in Mainz, Germany, made the extraordinary claim that they had seen hydrogen sulphide superconducting at −70 °C. That’s some 20 degrees hotter than any other material—a huge increase over the current record.

Eremets and co have worked hard to conjure up the final pieces of conclusive evidence. A few weeks ago, their paper was finally published in the peer reviewed journal Nature, giving it the rubber stamp of respectability that mainstream physics requires. Suddenly, superconductivity is back in the headlines.

Today, Antonio Bianconi and Thomas Jarlborg at the Rome International Center for Materials Science Superstripes in Italy provide a review of this exciting field. These guys give an overview of Eremet and co’s discovery and a treatment of the theoretical work that attempts to explain it.

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Nov 8, 2015

Theory of a Mach Effect Thruster I

Posted by in categories: energy, information science, materials, space travel

ABSTRACT

The Mach Effect Thruster (MET) is a propellant―less space drive which uses Mach’s principle to produce thrust in an accelerating material which is undergoing mass―energy fluctuations, [1] –[3]. Mach’s principle is a statement that the inertia of a body is the result of the gravitational interaction of the body with the rest of the mass-energy in the universe. The MET device uses electric power of 100 — 200 Watts to operate. The thrust produced by these devices, at the present time, are small on the order of a few micro-Newtons. We give a physical description of the MET device and apparatus for measuring thrusts. Next we explain the basic theory behind the device which involves gravitation and advanced waves to incorporate instantaneous action at a distance. The advanced wave concept is a means to conserve momentum of the system with the universe. There is no momentun violation in this theory. We briefly review absorber theory by summarizing Dirac, Wheeler-Feynman and Hoyle-Narlikar (HN). We show how Woodward’s mass fluctuation formula can be derived from first principles using the HN-theory which is a fully Machian version of Einstein’s relativity. HN-theory reduces to Einstein’s field equations in the limit of smooth fluid distribution of matter and a simple coordinate transformation.

Keywords:

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Nov 7, 2015

Bitdrones: Interactive quadcopters allow for ‘programmable matter’ explorations

Posted by in categories: biotech/medical, materials, robotics/AI

Could an interactive swarm of flying “3D pixels” (voxels) allow users to explore virtual 3D information by interacting with physical self-levitating building blocks? (credit: Roel Vertegaal)

We’ll find out Monday, Nov. 9, when Canadian Queen’s University’s Human Media Lab professor Roel Vertegaal and his students will unleash their “BitDrones” at the ACM Symposium on User Interface Software and Technology in Charlotte, North Carolina.

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Nov 3, 2015

Ultrasensitive sensors made from boron-doped graphene

Posted by in categories: electronics, materials, particle physics

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.

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Nov 3, 2015

Unbreakable glass that’s as strong as steel created

Posted by in category: materials

University of Tokyo develops unbreakable glass that could revolutionise construction, manufacturing and dinner parties.

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Nov 2, 2015

New Electronic Skin Can Sense Sound and Temperature

Posted by in categories: cyborgs, materials

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.

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Nov 2, 2015

Cryonics Is No Fantasy, Should We Be Taking It Seriously?

Posted by in categories: cryonics, life extension, materials, neuroscience

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.

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Nov 2, 2015

New artificial skin can detect pressure and heat simultaneously

Posted by in categories: computing, cyborgs, materials, mobile phones, robotics/AI

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 , 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 meant to mimic the human fingerprint (it can sense texture), beneath that sit sensors sandwiched between . 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.

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Oct 29, 2015

Is black phosphorous the next big thing in materials?

Posted by in categories: engineering, materials

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 has been predicted recently for 2D black phosphorous crystals by theorists but never before observed.”

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Oct 28, 2015

New silicon-based anode set to boost lifetime and capacity of lithium-ion batteries

Posted by in categories: energy, materials, nanotechnology

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.

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