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The rapid development of air filters is closely related to the development of military industry and electronic industry. In the first world war, the use of various chemical agents, asbestos fibre filter paper as the smoke filter layer of military gas masks came into being. The glass fiber filter medium is used in air filtration to obtain a patent in the United States in October 1940. In the 1950s, the United States studied the production process of glass fiber filter paper, and the air filter was improved and developed. In the 1960s, HEPA filters came out; In the 1970s, the filter paper of fine glass fiber was used as the HEPA filter of filter medium, and the filtration efficiency of particle size of 013 micron particle diameter was 99.9998%. Since the eighty s, with the emergence of new test method, use evaluation to improve and to improve the filtering performance requirements, found the HEPA filter there is a serious problem, and he had a higher ULPA filter performance. Countries are still working on it and expect more advanced air filters soon
For years, car and motorcycle enthusiasts are already replacing their standard steel wheels with larger alloy wheels and hubcaps. At a glance, it's not hard to see why these alloy wheels have grown to be very popular. Not only do they supply a smoother ride than regular steel wheels, but also they look flashier and invite vehicles to stand out. This trend hasn't been lost on manufacturers; even new SUVs, compact cars and vans are coming built with large and flashy alloy wheels.
At the 2011 MTV EMAs held on 6th November at Odyssey Arena in Belfast, the pop sensation was nominated for three categories including 'Biggest Fans' but won two trophies: 'Best Pop Act' and 'Best Male'. It is necessary to convey that together with his awards, the 17-year-old star received a stirring praise in the Odyssey Arena crowd as treating audiences and viewers in your own home to "Mistletoe" from his newly released Christmas album named "Under the Mistletoe" together with his hit single "Never Say Never". Beside his EMAs performance, Bieber has says he plans on taking a paternity test to bring a conclusion to claims created by Mariah Yeater which he fathered her baby. Some sources also declare that Justin Bieber has hired legal eagle Howard Weitzman to produce the DNA test with some plans to file a huge lawsuit against Yeater, 20, soon once Justin Bieber has returned from your MTV Europe Music Awards in Belfast following your results prove he is not the dad of her three-month baby.
Depth indication: you can tell which metal objects detected are buried in depth;
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