Scientists have created a printer that uses just water to print instead of ink. After about 22 hours, the paper fades back to a plain sheet of white paper, allowing it to be reused. A group of chemists assert that the “water-jet” technology, that is capable of reprinting numerous times, spares people their money and saves trees.
"Several international statistics indicate that about 40 percent of office prints [are] taken to the waste paper basket after a single reading," Sean Xiao-An Zhang, a chemistry professor at Jilin University in China, who supervised the work, said. The paper alone is not ordinary at all, as it is coated with an invisible dye that shows color when water hits it. Later on, the print slowly fades away within a matter of 22 hours, but disappears much faster if exposed to high levels of heat. According to the designers, the print comes out clear and the technology is not expensive at all. "Based on 50 times of rewriting, the cost is only about 1 percent of the inkjet prints," Zhang said in a video. If one page were reused just 12 times, the cost would only be one-seventeenth that of its inkjet counterpart. Zhang said dye-treating the paper, of the type generally used for printing, added about five percent to its price, but this is more than compensated for by the saving on ink. There is no need to change the printer, but the ink cartridge needs to be filled up with water with the help of a syringe. "Water is a renewable resource and obviously poses no risk to the environment," said the study. In the past, such ventures using disappearing ink gave way to low-contrast results at a high price, with some methods using questionable chemicals. Oxazolidine, a dye compound, is the type of mix Zhang and his group used to print off the paper, with clear blue showing in less than one second after the water was put on the page. Four water colors can be printed for the time being, which are blue, magenta, gold, and purple. However, only one color can be printed off at a time. The team hopes to make the resolution and duration time for printing better. Zhang said the dyed paper was "very safe" but toxicity tests are underway on mice to be sure. Voice of Russia, The Sydney Morning Herald Source: http://sputniknews.com/
London: Scientists have developed a new battery made with aluminium-filled capsules that could charge your cellphone in six minutes. The battery has four times the capacity of current lithium ion batteries and degrades less over time. It uses nanoparticles with a shell of titanium dioxide wrapped around aluminium, which acts as the battery's negative electrode. Researchers at the Massachusetts Institute of Technology and Tsinghua University in Beijing found that the metal could expand and shrink freely by encasing the aluminium inside a shell, 'The Times' reported. The research overcomes previous problems experienced using aluminium in rechargeable lithium ion batteries. Aluminium is a high-capacity material but it can double in volume and shrink again as it is charged and discharged. The repeated shedding and reforming of the layer consumes lithium and reduces the battery's capacity. The study was published in the journal Nature Communications. — PTI. 
