Since the 1850s scientists have known that crystalline materials are organized into fourteen different basic lattice structures. However, a team of researchers from Vanderbilt Univ. and Oak Ridge National Laboratory now reports that it has discovered an entirely new form of crystalline order that simultaneously exhibits both crystal and polycrystalline properties, which they describe as "interlaced crystals."
For much the same reason LCD televisions offer...
It’s estimated that more than half of U.S. energy is wasted as heat. Mostly, this waste heat...
Thermal systems use heat to produce cold, and vice versa. The human body demonstrates this...
Vast amounts of excess heat are generated by industrial processes and by electric power plants; researchers around the world have spent decades seeking ways to harness some of this wasted energy. Most such efforts have focused on thermoelectric devices, solid-state materials that can produce electricity from a temperature gradient, but the efficiency of such devices is limited by the availability of materials.
Materials that can be used for thermoelectric devices have been known for decades. But, until now, there has been no good explanation for why just a few materials work well for these applications, while most others do not. Now researchers say they have finally found a theoretical explanation for the differences, which could lead to the discovery of new, improved thermoelectric materials.
One strategy for addressing the world’s energy crisis is to stop wasting so much energy when producing and using it, which can happen in coal-fired power plants or transportation. Nearly two-thirds of energy input is lost as waste heat. Now Northwestern Univ. scientists have discovered a surprising material that is the best in the world at converting waste heat to useful electricity.
Because of their unique qualities, thermoelectric materials can convert waste heat into electricity. Researchers in the Netherlands have managed to significantly improve the efficiency of a common thermoelectric material by adjusting the fabrication conditions. The material may eventually be used to, for example, put the heat issued from a factory chimney or car exhaust pipe to good use.
Imagine a computer so efficient that it can recycle its own waste heat to produce electricity. While such an idea may seem far-fetched today, significant progress has already been made to realize these devices. Researchers at the Univ. of Utah have fabricated spintronics-based thin film devices which do just that, converting even minute waste heat into useful electricity.
Univ. of Colorado Boulder scientists have found a creative way to radically improve thermoelectric materials, a finding that could one day lead to the development of improved solar panels and more energy-efficient cooling equipment. The technique, building an array of tiny pillars on top of a sheet of thermoelectric material, represents an entirely new way of attacking a century-old problem.
To understand how to design better thermoelectric materials, researchers are using neutron scattering at the Spallation Neutron Source and the High Flux Isotope Reactor at Oak Ridge National Laboratory to study how silver antimony telluride is able to effectively prevent heat from propagating through it on the microscopic level.
The phonon, like the photon or electron, is a physical particle that travels like waves, representing mechanical vibration. Phonons transmit everyday sound and heat. Recent progress in phononics by a research scientist at Georgia Institute of Technology has led to the development of new ideas and devices that are using phononic properties to control sound and heat, even to the point of freeing bustling city blocks from the noise of traffic.
Researchers have recently provided the first evidence ever that it is possible to generate a magnetic field by using heat instead of electricity. The phenomenon is referred to as the Magnetic Seebeck effect or “thermomagnetism”.
In recent years, thermoelectric materials have enabled the re-use of otherwise wasted thermal energy as electrical power. But this ability is limited to materials, typically complex crystals, exhibiting high electrical conductivity and low thermal conductivity. Scientists have now discovered a way of suppressing thermal conductivity in sodium cobaltate, opening new paths for energy scavenging.
A new study published in Nature Materials has found a way to suppress the thermal conductivity in sodium cobaltate so that it can be used to harvest waste energy. Led by scientists at Royal Holloway Univ., the team conducted a series of experiments on crystals of sodium cobaltate grown in the University's Dept. of Physics.
A team led by Lawrence Berkeley National Laboratory Materials Sciences Division’s Jeffrey Urban and Rachel Segalman have discovered highly conductive polymer behavior occurring at a polymer/nanocrystal interface. The composite organic/inorganic material is a thermoelectric—a material capable of converting heat into electricity—and has a higher performance than either of its constituent materials.
Thermoelectric materials can be used to turn waste heat into electricity or to provide refrigeration without any liquid coolants, and a research team from the University of Michigan has found a way to nearly double the efficiency of a particular class of them that's made with organic semiconductors.
For years, researchers have developed thin films of bismuth telluride, which converts heat into electricity or electricity to cooling, on top of gallium arsenide to create cooling devices for electronics. But it was not clear how this could be done because the atomic structures do not appear to be compatible. Researchers from North Carolina State University and RTI International have now solved the mystery.
Thermoelectric efficiency has improved enough to enable limited commercial use, but lack of better materials has prevented widespread adoption. New development work at Massachusetts Institute of Technology could help reduce thermal conductivity while keeping electrical conductivity high. In addition to computer modeling, the researchers draw upon methods developed by optics researchers who have been attempting to create invisibility cloaks—ways of making objects invisible to certain radio waves or light waves using nanostructured materials that bend light.
Researchers at the Aalto University School of Chemical Technology have applied atomic layer deposition (ALD) technique to the synthesis of thermoelectric materials. Converting waste energy into electricity, these materials are a promising means of producing energy cost-effectively and without carbon dioxide emissions in the future.
By using common materials found pretty much anywhere there is dirt, a team of Michigan State University researchers have developed a new thermoelectric material. The new material mimic natural minerals known as tetrahedrites and can be processed economically by grinding them to a powder, then using pressure and heat to compress them into useable sizes.
Thermoelectric devices, which can harness temperature difference to produce electricity, might be made more efficient thanks to new research from Massachusetts Institute of Technology on heat propagation through structures called superlattices. The new findings show, unexpectedly, that heat can travel like waves, rather than particles, through these nanostructures.
Northwestern University scientists have developed a thermoelectric material that is, according to the university, the best in the world at converting waste heat to electricity, which is good news once one realizes nearly two-thirds of energy input is lost as waste heat. The material could signify a paradigm shift.
Graphene, a single-atom-thick layer of carbon, has spawned much research into its unique electronic, optical, and mechanical properties. Now, researchers at Massachusetts Institute of Technology have found another compound that shares many of graphene's unusual characteristics—and in some cases has interesting complementary properties to this much-heralded material.
Engineers at Purdue University have coated glass fibers with a new thermoelectric material formed by dipping glass fibers in a solution containing nanocrystals of lead telluride and then exposing them to heat in a process called annealing to fuse the crystals together. The resulting material is far less brittle and more effiicient to produce than conventional thermoelectrics.
In the continual quest for better thermoelectric materials—which convert heat into electricity and vice versa—researchers have identified a liquid-like compound whose properties give it the potential to be even more efficient than traditional thermoelectrics.
Scientists from the Chinese Academy of Science's Shanghai Institute of Ceramics, in collaboration with scientists from Brookhaven National Laboratory, the University of Michigan, and the California Institute of Technology, have identified a new class of high-performance thermoelectric materials. In their study, liquid-like copper ions carry electric current around a solid selenium crystal lattice.
Made from carbon nanotubes locked up in flexible plastic fibers and made to feel like fabric, an invention called Power Felt from Wake Forest University uses temperature differences—room temperature versus body temperature, for example—to create a charge.
A team of Massachusetts Institute of Technology researchers has developed a way of making a high-temperature version of a kind of materials called photonic crystals, using metals such as tungsten or tantalum. The new materials—which can operate at temperatures up to 1,200 C—could find a wide variety of applications powering portable electronic devices, spacecraft to probe deep space, and new infrared light emitters that could be used as chemical detectors and sensors.
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