For decades, scientists have theorized that the movement of Earth’s tectonic plates is driven largely by negative buoyancy created as they cool. New research, however, shows plate dynamics are driven significantly by the additional force of heat drawn from the Earth’s core. (more…)
A new study from North Carolina State University researchers finds that novel light-weight composite metal foams (CMFs) are significantly more effective at insulating against high heat than the conventional base metals and alloys that they’re made of, such as steel. The finding means the CMF is especially promising for use in storing and transporting nuclear material, hazardous materials, explosives and other heat-sensitive materials, as well as for space exploration. (more…)
Groundbreaking observations could help develop better, more efficient materials for electronics and alternative energy
Using a state-of-the-art ultrafast electron microscope, University of Minnesota researchers have recorded the first-ever videos showing how heat moves through materials at the nanoscale traveling at the speed of sound. (more…)
North Carolina State University researchers have come up with a new technique for improving the connections between stacked solar cells, which should improve the overall efficiency of solar energy devices and reduce the cost of solar energy production. The new connections can allow these cells to operate at solar concentrations of 70,000 suns worth of energy without losing much voltage as “wasted energy” or heat.
Stacked solar cells consist of several solar cells that are stacked on top of one another. Stacked cells are currently the most efficient cells on the market, converting up to 45 percent of the solar energy they absorb into electricity. (more…)
Researchers from North Carolina State University have developed a way to melt or “weld” specific portions of polymers by embedding aligned nanoparticles within the materials. Their technique, which melts fibers along a chosen direction within a material, may lead to stronger, more resilient nanofibers and materials.
Physicists Jason Bochinski and Laura Clarke, with materials scientist Joe Tracy, placed specifically aligned gold nanorods within a solid material. Gold nanorods absorb light at different wavelengths, depending upon the size and orientation of the nanorod, and then they convert that absorbed light directly into heat. In this case, the nanorods were designed to respond to light wavelengths of 520 nanometers (nm) in a horizontal alignment and 800 nm when vertically aligned. Human beings can see light at 520 nm (it looks green), while 808 nm is in the near infrared spectrum, invisible to our eyes. (more…)
Ever wonder why sand can both run through an hourglass like a liquid and be solid enough to support buildings? It’s because granular materials – like sand or dirt – can change their behavior, or state. Researchers from North Carolina State University have found that the forces individual grains exert on one another are what most affect that transition.
Physicists have explored the changing behavior of granular materials by comparing it to what happens in thermodynamic systems. In a thermodynamic system, you can change the state of a material – like water – from a liquid to a gas by adding energy (heat) to the system. One of the most fundamental and important observations about temperature, however, is that it has the ability to equilibrate: a hot cup of tea eventually cools to match the temperature of the room. (more…)
A team of materials scientists at Harvard University and the University of Exeter has invented a new fibre which changes colour when stretched. Inspired by nature, the researchers identified and replicated the unique structural elements, which create the bright iridescent blue colour of a tropical plant’s fruit.
The multilayered fibre, described in the journal Advanced Materials, could lend itself to the creation of smart fabrics that visibly react to heat or pressure.
“Our new fibre is based on a structure we found in nature, and through clever engineering we’ve taken its capabilities a step further,” says lead author Dr Mathias Kolle, a postdoctoral fellow at the Harvard School of Engineering and Applied Sciences (SEAS). “The plant, of course, cannot change colour. By combining its structure with an elastic material, however, we’ve created an artificial version that passes through a full rainbow of colours as it’s stretched.” (more…)
Hands-on activities broaden engineering students’ view of thermodynamics
Carbon dioxide, candle wax, a hobby rocket and water would not seem to have much in common but they all were among the topics presented by 14 students in the Honors sections of the course MEEG341 Thermodynamics on Wednesday, Dec. 5, as a means to cement classroom learning.
“I want students to leave the course knowing there are many uses for what they learn in this class, learning that they can apply later on as real-world engineers,” said Lian-Ping Wang, a mechanical engineering professor who holds a joint appointment as professor of physical ocean science and engineering. (more…)
