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A new thermal “invisibility cloak” is able to make objects invisible by redirecting the heat around them, researchers say.
Even though invisibility cloaks used to only be sported by fictional characters such as Harry Potter, nowadays they have become a reality. The way they work is by redirecting the light waves around the cloaked objects.
Scientists have also developed other types of cloaking devices that are able to redirect acoustic waves.
Cloaking devices that can make objects appear thermally invisible are not a new invention. However, one important difference between the old cloaking devices and the new one, is that the old ones did not have an on and off switch. A second difference that has to be mentioned it that the previous cloaks could not change their shape and had to be tailored depending on the objects that was being cloaked.
Baile Zhang, an assistant professor at the Division of Physics and Applied Physics School of Physical & Mathematical Sciences at the Nanyang Technological University in Singapore, stated that when working on this new project, him and his colleagues wanted to develop a controllable cloak that could adjust to environmental changes, as well as to the object to be cloaked.
Zhang and his team have developed a thermal “invisibility cloak” that can easily adapt to whatever object it has to cloak, without affecting its efficiency. Another improvement that the scientists made, was to implement an on and off switch feature.
The new thermal “invisibility cloak” is quite complex. A number of 24 devices were needed in order to develop the cloak. They are called thermoelectric modules and they work by moving around the heat that surrounds the object. The devices are extremely tiny and measure 0.24 by 0.24 by 0.15 inches (0.6 by 0.6 by 0.38 centimetres).
The cloak shifts heat around an air hole that is 2.44 inches (6.2 centimetres) wide. The heat cannot be diffused through the hole when temperatures are between 32 to 140 degrees Fahrenheit (0 to 60 degrees Celsius).
According to Zhang, the thickness of the cloak could be similar to that of human skin. It could be used in the future to shield the satellites that change their shape over time. “The active thermal cloak might also be applied in human garments for effective cooling and warming, which makes a lot of sense in tropical areas such as Singapore,” Zhang added.
The scientists are still working on ways to improve the thermal “invisibility cloak”, and are especially focused on the ability of the device to transfer heat.
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