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Monday, December 19, 2011

Could Discoveries in Superconductivity Finally Give Us Hoverboards?

From the act of virtually seeing inside the human body with medical imaging technology to helping physicists in their quest to discover the origins of mass in matter, superconductors are already incredibly useful. 

One of the most important applications of superconductors is making powerful electromagnets. In electronics, it is a basic principle that as electrical charges travel through conducting material, like current flowing through winding strands of copper wire, it generates heat and loses energy. Since the electric and magnetic fields are tied together, when charge passes through the wire it conducts electricity, it also creates a magnetic field. But, superconducting wire can carry an immense amount of electrical current without the effects of heating or energy loss. In this state of superconductivity, magnetic fields gets expelled from the equation by sending the electric current towards the outer surface, thereby, squeezing out any magnetic flux. This not yet fully understood phenomena is also known as, the Meisser effect. But what we do know, is that when the magnetic fields of the superconductor get cancelled out, the electrical currents do not change, or decay, with time. The electrical current can travel without a power source to drive it - infinitely! So, it's not just a clever name, it really is a super-conductor.    

One hundred years ago, Dutch physicist, Heike Kamerlingh Onnes and his team found that certain materials completely lose their electrical resistance when cooled to a temperature that is within what is called "absolute zero". The following quote is from the 'History of Superconductors' section on Superconductors.org, a non-profit, non-affiliated website intended to introduce beginners and non-technical people to the world of superconductors. 

"Superconductors, materials that have no resistance to the flow of electricity, are one of the last great frontiers of scientific discovery. Not only have the limits of superconductivity not yet been reached, but the theories that explain superconductor behavior seem to be constantly under review. In 1911 superconductivity was first observed in mercury by Dutch physicist Heike Kamerlingh Onnes of Leiden University. When he cooled it to the temperature of liquid helium, 4 degrees Kelvin (-452F, -269C), its resistance suddenly disappeared. The Kelvin scale represents an "absolute" scale of temperature. Thus, it was necessary for Onnes to come within 4 degrees of the coldest temperature that is theoretically attainable to witness the phenomenon of superconductivity. Later, in 1913, he won a Nobel Prize in physics for his research in this area." (Eck 2011)

Within fifty years of the discovery made by Heike Onnes and his team, superconductivity was though to have been fully explained by a simple beautiful elegant theory, when in 1986, an ugly disproving fact overturned it all.

It seems that superconducting materials are still surprising us. Three years ago, in the Science and Technology of Advanced Materials, an international forum for refereed original contributions and reviews covering all aspects of materials science, Tadashi C Ozawa and Susan M Kauzlarich published a journal titled, "Chemistry of layered d-metal pnictide oxides and their potential as candidates for new superconductors", covering their new findings of an (iron-based) superconducting material. In 2008, Charles Q. Choi wrote about this story in the April 23rd issue of Scientific American, "Iron Exposed as High-Temperature Superconductor: New class of superconductor may help pin down mysterious physics",

"For more than 20 years, the only known superconductors that worked far above liquid-helium temperatures were a few dozen compounds—virtually all based on copper. Now scientists have discovered the first high-temperature superconductors based on iron. These novel materials could help unravel one of the biggest mysteries in science—how exactly the high-temperature versions work"(Choi 2008)

These iron-based superconductors that were discovered three years ago were utterly unexpected, and this highlights just how much we still have to learn. The following video is from the article, "Superconducting disc locked in upside-down levitation", posted on the "New ScientistTV Blogs section", under 'Physics and Math' in October 2011. It may seem to be some kind of reversed alien technology, but I assure you, it is perfectly explainable simply using the most natural laws of physics. The key ingredient in effect here lies within the material of the disc. It's make-up consists of poor electrical conducting sapphire crystals, while being coated with an outer layer of superconducting material known as yttrium barium copper oxide. As you can see from the video, the disc can be locked into position because of the love-hate relationship between superconducting fields and magnetic fields. There are tiny, tiny gaps in the disc which allow for some of the magnetic field to seep in, trapping them inside weak area's. Those tiny spaces can hold up the disc by acting as invisible "pins".   


-Demonstration by physicist Boaz Almog from Tel Aviv University, Israel, at the Association of Science-Technology Centers (ASTC) Annual Conference in Baltimore, Maryland, illustrates how a superconducting plate can be fixed in 3D space while levitating above a track of permanent magnets.

This video below is from the article titled, "Superconductor flying saucer stunts", and it also appears on "New ScientistTV" in addition to those previously shown experiments from Boaz Almog and his team at Tel Aviv University.



-Filmed by physicist Boaz Almog and his colleagues at Tel Aviv University's superconductivity group, the clip builds upon Almog's 'hit demonstration' from the Association of Science-Technology Centers


As you can see from the clouds of gas in these two video's, the superconducting materials are cooled with liquid nitrogen. One of the main goals to help further the applications of this research is to find a material that can be superconducting at room temperature. As important as those achievements which have been made up to this point are, their potential for a future revolution in technology may be even greater. Then just maybe, we can all get our "Hoverboards".

http://www.davekeeshan.com/where-is-my-hoverboard/