ПОМОГИТЕ ВСТАВИТЬ СЛОВА В ПРОПУСКИ! ПОЖАЛУЙСТА!!!
Ultraviolet
light
photochemistry
domestic
hydrogen
bugs
chemicals
sewage
germ-free
bug-killing
Scientists have found new ways to shed light on the old problem of pollution - by using 1_____________ lamps to eradicate bacteria. They have discovered that if sewage or other effluent is mixed with titanium dioxide, the basic ingredi¬ent of paint, and then exposed to ultra-violet 2 ______________, the result is annihilation of all 3 _______________. This startlingly simple and cheap technique was revealed at last month's British Association for the Advancement of Science meeting in Swansea when researchers outlined their latest discoveries in the rapidly expanding field of 4 ______________, the study of compounds that react to light. The ultraviolet project, a spin-off from research aimed at producing 5 _____________ fuel from sea water, has widespread applications. For example, simple, yet highly effective devices for removing legionella bac¬teria from office air conditioning systems could be built this way, said Dr Andrew Mills of Swansea University. In addition, pilot 6 _____________ plants that use ultraviolet light are already being tested in America and Britain. There are two parts to the 7 ______________ system. Firstly, titanium dioxide is mixed in water. Then, when ultraviolet light is shone on the mixture, the titanium dioxide becomes energized and begins to oxidize chemicals it comes in contact with. 'Any bacteria that touch the granules are mineral¬ized,' said Dr Mills, who presented the keynote Kelvin Lecture at the association meeting in Swansea. 'It is an extremely simple but powerful effect.' The action produced is similar to that of household bleach, which one day could be replaced by ultraviolet light, he added. 'One idea is to use ultraviolet light to make the 8 _____________ toilets of the future. The toilet would be coated in titanium dioxide and then an ultra-violet light would shine when the seat is put down, just as a fridge light comes on when its door is opened. Bacteria wouldn't have a chance.' This last idea may seem a trifle eccentric. Nevertheless, several major companies, including Unilever, have recently begun research on ultraviolet-powered 9 ______________ appliances, though most of this effort has concentrated on developing washing machines. Instead of using heat and detergents to break down and remove dirt on clothes, ultra-violet light would do the job. Apart from saving on electricity, such devices would avoid the use of poisonous chemicals, like bleach, or detergents that have harmful environmental effects. 'That is the real motive of our research', added Dr Mills. 'Light-powered devices will free us from using damaging 10 _______________, and also from having to generate electricity to provide heat – and that will have a con¬siderable number of benefits, particularly for the environment.'