Researchers Closer to the Ultimate Green ‘Magnetic’ Refrigerator
Scientists are a step closer to making environmentally-friendly ‘magnetic’ refrigerators and air conditioning systems a reality, thanks to new research published today in Advanced Materials.
Magnetic refrigeration technology could provide a ‘green’ alternative to traditional energy-guzzling gas-compression fridges and air conditioners. They would require 20-30% less energy to run than the best systems currently available, and would not rely on ozone-depleting chemicals or greenhouse gases. Refrigeration and air conditioning units make a major contribution to the planet’s energy consumption - in the USA in the summer months they account for approximately 50% of the country’s energy use.
A magnetic refrigeration system works by applying a magnetic field to a magnetic material - some of the most promising being metallic alloys - causing it to heat up. This excess heat is removed from the system by water, cooling the material back down to its original temperature. When the magnetic field is removed the material cools down even further, and it is this cooling property that researchers hope to harness for a wide variety of cooling applications. (more…)
Magnetism Could Address a Major Problem Facing Bioengineers
Melissa Krebs, third-year biomedical engineering graduate student at Case Western Reserve University is first co-author of the "Formation of Ordered Cellular Structures in Suspension via Label-Free Negative Magnetophoresis," appearing online in advance of the May publication of Nano Letters. (Credit: Case Western Reserve University)
The power of magnetism could be an enabling technology to address a major problem facing bioengineers as they try to create new tissue—getting human cells to not only form structures, but to stimulate the growth of blood vessels to nourish their growth.
A multidisciplinary team of investigators from Case Western Reserve University, Duke University and University of Massachusetts, Amherst, created an environment where magnetic particles suspended within a specialized liquid solution acted like molecular sheep dogs by nudging free-floating human cells to form chains in response to external magnetic fields. These chains, the researchers said, could potentially be integrated into approaches for creating human tissues and organs.
These cells not only naturally adhere to each other upon contact, the researchers said, but the aligned cellular configurations formed may promote or accelerate the creation and growth of tiny blood vessels.
“The cells have receptors on their surfaces that have an affinity for other cells,” said Melissa Krebs, third-year biomedical engineering graduate student at Case Western Reserve University Biomedical Engineering and first co-author of the “Formation of Ordered Cellular Structures in Suspension via Label-Free Negative Magnetophoresis,” appearing online in advance of the May publication of Nano Letters, a journal published by the American Chemical Society. “They become sticky and attach to each other. When endothelial cells get together in a linear fashion, as they did in our experiments, it may help them to organize into tiny tubules.” (more…)
Discovery: Magnetism Governs Properties of Iron-Based Superconductors
NIST research shows that magnetism plays a key role in iron pnictide superconductors' crystal structure. (Iron is purple; arsenic is yellow; calcium is green.) Only if the iron's magnetism is taken into account do calculations of the distance between these crystal layers match up with lab measurements. (Credit: Yildirim, NIST)
Though a year has passed since the discovery of a new family of high-temperature superconductors, a viable explanation for the iron-based materials’ unusual properties remains elusive. But a team of scientists working at the National Institute of Standards and Technology (NIST) may be close to the answer.
The team has found strong evidence that magnetism is a pivotal factor governing the physical properties of iron pnictides, a group of materials that conduct electricity without resistance at temperatures of up to 56 kelvin (-217 degrees celsius). Iron pnictides are composed of regularly spaced layers of iron sandwiched between other substances. And although -217 might sound pretty cold, they are the first class of materials found to superconduct at that high a temperature since the discovery of copper-based superconductors more than two decades ago. (more…)
Secrets Behind High Temperature Superconductors Revealed
In a physics lab, a fun experiment uses a liquid nitrogen cooled ceramic superconductor to levitate a small magnet. (Ttfnrob. CC AN2.0 Generic)
Scientists from Queen Mary, University of London and the University of Fribourg (Switzerland) have found evidence that magnetism is involved in the mechanism behind high temperature superconductivity.
Writing in the journal Nature Materials, Dr Alan Drew from Queen Mary’s Department of Physics and his colleagues at the University of Fribourg report on the investigation of a new high temperature superconductor, the so-called oxypnictides. They found that these exhibit some striking similarities with the previously known copper-oxide high temperature superconductors - in both cases superconductivity emerges from a magnetic state. Their results go some way to explaining the mechanisms behind high temperature superconductors. (more…)
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