New research from Rice University and the University of Oulu in Oulu, Finland, finds that carbon nanotubes could significantly improve the performance of electrical commutators that are common in electric motors and generators.
The research, which appeared online this month in the journal Advanced Materials, finds that "brush contact" pads made of carbon nanotubes had 10 times less resistance than did the carbon-copper composite brushes commonly used today. Brush contacts are an integral part of "commutators," or spinning electrical switches used in many battery-powered electrical devices, such as cordless drills.
"The findings show that nanotubes have a great deal of practical relevance as brush contacts," said lead researcher Pulickel Ajayan, Rice's Benjamin M. and Mary Greenwood Anderson Professor in Mechanical Engineering and Materials Science. "The technology is widely used in industry, both in consumer gadgets as well as larger electrical machinery, so this could be a very interesting, near-term application for nanotubes." The combination of mechanical and electrical properties of nanotubes makes this possible.
The carbon nanotubes used in the study are hollow tubes of pure carbon that are about 30 nanometers in diameter. By comparison, a human hair is about 100,000 nanometers in diameter. In addition to being small, nanotubes are also extremely lightweight and durable, and they are excellent conductors of heat and electricity.
Because of these properties, the researchers decided to test nanotubes as brush contacts. Brush contacts are conducting pads held against a spinning metal disc or rod by spring-loaded arms. Current is passed from the spinning disc through the brush contacts to other parts of the device.
To test the feasibility of using carbon nanotube brush contacts, the research team replaced the ordinary copper-carbon composite brushes of an electric motor with small blocks that contain millions of carbon nanotubes. Under an electron microscope, these millimeter-square blocks look like a tightly packed forest.
From Ajayan's previous work, the team knew that these nanotube forests react something like a "memory foam" pillow; they regain their shape very quickly after they are compressed.
"This elasticity is something that's not found in existing composites that are used for brush contacts, and that's the essence of why the nanotube brush contacts perform better: They keep much more of their surface area in contact with the spinning disc," said Robert Vajtai, faculty fellow at Rice. Vajtai worked on the study with Ajayan and a group of researchers in Finland led by University of Oulu Researcher Krisztian Kordas.
The team believes that the improved contact between the surface of the spinning disc and the brush accounts for the 90 percent reduction in lost energy.
Jade Boyd | EurekAlert!
Argon is not the 'dope' for metallic hydrogen
24.03.2017 | Carnegie Institution for Science
Researchers make flexible glass for tiny medical devices
24.03.2017 | Brigham Young University
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy