Posted on

APPLICATIONS OF SUPERCONDUCTORS

SUPER CONDUCTIVITY

APPLICATIONS OF SUPERCONDUCTORS


APPLICATIONS OF SUPERCONDUCTORS

https://kredoz.com/notes-study-material/

The above ISIS graph gives a rough breakdown of the various markets in which superconductors are expected to make a contribution.

Soon after Kamerlingh Onnes discovered superconductivity, scientists began dreaming up practical applications for this strange new phenomenon. Powerful new superconducting magnets could be made much smaller than a resistive magnet, because the windings could carry large currents with no energy loss. Generators wound with superconductors could generate the same amount of electricity with smaller equipment and less energy. Once the electricity was generated it could be distributed through superconducting wires. Energy could be stored in superconducting coils for long periods of time without significant loss.

Squids: The recent discovery of high temperature superconductors brings us a giant step closer to the dream of early scientists. Applications currently being explored are mostly extensions of current technology used with the low temperature superconductors. Current applications of high temperature superconductors include; magnetic shielding devices, medical imaging systems, superconducting quantum interference devices (SQUIDS), infrared sensors, analog signal processing devices, and microwave devices. As our understanding of the properties of superconducting material increases, applications such as; power transmission, superconducting magnets in generators, energy storage devices, particle accelerators, levitated vehicle transportation, rotating machinery, and magnetic separators will become more practical.

Electric Power Transmission Line: The ability of superconductors to conduct electricity with zero resistance can be exploited in the use of electrical transmission lines. Currently, a substantial fraction of electricity is lost as heat rough resistance associated with traditional conductors such as copper or aluminium. A large scale shift to super conductivity technology depends on whether wires can be prepared from the brittle ceramics that retain their superconductivity at 77 K while supporting large current densities.

PRINCIPLE OF MAGNETIC LEVITATION

The diamagnetic property of superconductor is the basis of magnetic levitation. A sheet of superconductor in the superconducting state is kept below the horizontal bar magnet suspended from a flixble chain and then lowered over the superconductor. As the magnet approaches the superconductor, the supporting chain becomes limp and eventually dropped down in a loop below the magnet which flots horizontally above the supercomputer. The magnetic field due to the approaching magnet induces a current in the surface of the superconductor. Since the resistance of the superconductor is zero, the current persists in the superconductor and a magnetic field due to this induced current repels the bar magnet. When a superconductor levitates a magnets, a magnetic morror image is formwed in the superconductor such that there is always a north pole induced in the superconductor directly below the south pole of the levitating magnets. The mirror image moves with the magnet as the magnet moves so that the disc magnet can be given a rapid spin without affecting its levitations. In fact the magnet may continue to spin for quite a long time because its spinning encounters no friction other than the friction of air resistance. When the surrounding air pressure id reduced, the levitating magnet rises higher. Instead of permanent magnets, the supporting field is provided by a superconducting solenoid earring a current. The repulsion between the supporting magnetic fields and superconducting surface having persistent current is basis for magnetic levitation of train and other machine.

Superconducting Computer Elements: The field of electronics holds great promise for practical applications superconductors. The miniaturization and increased speed of computer chips are limited by the generation of heat and the charging time of capacitors due to the resistance of the interconnecting metal films. The use of new superconductive films may result in more densely packed chips which could transmit information more rapidly by several orders of magnitude. Superconducting electronics have achieved impressive accomplishments in the field of digital electronics. Logic delays of 13 picoseconds and switching times of 9 picoseconds have been experimentally demonstrated. Through the use of basic Josephson junctions scientists are able to make very sensitive microwave detectors, magnetometers, SQUIDs and very stable voltage sources.

Magnetic Leviation: The use of superconductors for transportation has already been established using liquid helium as a refrigerant. Prototype levitated trains have been constructed in Japan by using superconducting magnets. Magnetic-levitation is an application where superconductors perform extremely well. Transport vehicles such as trains can be made to “float” on strong superconducting magnets, virtually eliminating friction between the train and its tracks. Not only would conventional electromagnets waste much of the electrical energy as heat, they would have to be physically much larger than superconducting magnets. A landmark for the commercial use of MAGLEV technology occurred in 1990 when it gained the status of a nationally-funded project in Japan.

Superconducting Solinoids: Doctors need a non-invasive means of determining what’s going on inside the man body. By impinging a strong superconductor-derived magnetic field into the body, hydrogen atoms that exist in the body’s water and fat molecules are forced to accept energy from the magnetic field. They then release this energy at a frequency that can be detected and displayed graphically by a computer. The intense magnetic fields that are needed for these instruments are a perfect application of superconductors.

Superconductor Magnets: High-energy particle research hinges on being able to accelerate sub-atomic I particles to nearly the speed of light. Superconductor magnets make this possible. CERN, a consortium of several European nations, is doing something similar with its Large Hadron Collider (LHC) now constructed along the Franco-Swiss border.

Industry: New applications of superconductors will increase with critical temperature. Liquid nitrogen based superconductors has provided industry more flexibility to utilize superconductivity as compared to liquid helium superconductors. The possible discovery of room temperature superconductors has the potential to bring superconducting devices into our every-day lives.

Military Uses: The military is also looking at using superconductive tape as a means of reducing the length of very low frequency antennas employed on submarines. Normally, the lower the frequency, the longer an antenna must be. However, inserting a coil of wire ahead of the antenna will make it function as if it were much longer. Unfortunately, this loading coil also increases system losses by adding the resistance in the coil’s wire. Using superconductive materials can significantly reduce losses in this coil.

E-Bombs: The most ignominious military use of superconductors may come with the deployment of “E- bombs”. These are devices that make use of strong, superconductor-derived magnetic fields to create a fast, high- intensity electro-magnetic pulse (EMP) to disable an enemy’s electronic equipment. Such a device saw its first use in wartime in March 2003 when US Forces attacked an Iraqi broadcast facility.

Reduction in Green House Gas Emissions: Another impetus to the wider use of superconductors is political in nature. The reduction of green-house gas (GHG) emissions has becoming a topical issue due to the Kyoto Protocol which requires the European Union (EU) to reduce its emissions by 8% from 1990 levels by 2012. Physicists in Finland have calculated that the EU could reduce carbon dioxide emissions by up to 53 million tons if high-temperature superconductors were used in power plants.

The future melding of superconductors into our daily lives will also depend to a great degree on advancements in the field of cryogenic cooling. New, high-efficiency magnetocaloric-effect compounds such as gadolinium-silicon-germanium are expected to enter the marketplace soon. Such materials should make possible compact, refrigeration units to facilitate additional applications.

High-temperature superconductors are recent innovations from scientific research laboratories. New commercial innovations begin with the existing technological knowledge generated by the research scientist. Superconductivity has had a long history as a specialized field of physics. Through the collaborative efforts of government funded research, independent research groups and commercial industries, applications of new high-temperature superconductors will be in the not-so-distant future.


Other Link