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Robotic jelly fish—water powered Scientists at Virgina Tech in USA have invented an amazing robot that resembles a jelly fish. It is powered by water and can swim in it indefinitely. Named appropriately as “Robojelly”, it is coated with a layer of platinum on its surface that reacts with the water around it to create heat. This heat energy is used to provide power so that it can flex its artificial muscles and swim swiftly through water. The Robojelly has been developed under a project funded by the Office of Naval Research in USA and it is the prototype of future unmanned surveillance submarines that will scan the oceans unnoticed. The Robojelly has been designed on the moon jellyfish (Aurelia aurita).
Electricity generating carbon sheets Graphene comprises one-atom thick sheets of carbon atoms in which the atoms are arranged in hexagonal honeycomb patterns. It is the thinnest and strongest material known with excellent heat and electricity conducting properties. Andre Geim and Konstantin Novoselov at the University of Manchester were awarded the Nobel Prize in Physics for 2010 for their groundbreaking experiments on graphene. It has already found wide applications ranging from corrosion coatings to transistors and super-capacitors.
Now Reed and Mitchell Ong working at Stanford University have shown that graphene can actually generate electricity if it is subjected to mechanical stress. It can also change shape when an electric current is passed through it (i.e. it can behave as a “piezoelectric” material). This property was incorporated by introducing atoms of different elements such as hydrogen, lithium, potassium and fluorine on the flat carbon sheets.
This opens up a host of new applications in the field of acoustics, photonics, electronics and energy harvesting devices.
Mining with bacteria The world’s largest known deposits of copper are located in Chile and this metal represents about 70 per cent of the exports of Chile. The metal can be present in up to 30 per cent yield in the ore but in many places only small amounts of copper with only 1-2 per cent yields of copper are left. This is usually not extracted but treated as waste. The normal chemical process of extraction involves crushing of the ore, grinding it, followed by heating it to high temperatures so that the sulfides in it are converted to sulfoxides. It is then subjected to a number of refining processes including treatment with sulfuric acid and electrolysis. However, even small amounts of copper can be extracted if nature’s tiny workers—bacteria—are given the task. The process known as “biomining” is used in Chile, South Africa, Brazil, Australia and some other countries and about 20 per cent of world copper is produced in this manner. Bioleaching with suitable bacteria is also used for extraction of gold and uranium. The bacteria use the metals as a source of energy and thrive on them.
