A group of experts from around the world will conduct a conference on global catastrophic risks, the first of its kind. Discuss what should be done to prevent these risks from becoming realities that could put an end to human life as we know it on Earth, CNN reported. More info: Discovery Communications.
The speakers at the event four days at Oxford University in Britain will discuss topics such as terrorism, and that is what we must do if a large asteroid were in collision course with our planet.
On the last day of the Global Conference on Catastrophic Risk, experts will focus on the possible impact of new technologies such as super-machines that, if they are ill-conceived, could cause the disappearance of homo sapiens.
Polyvinyl chloride, or, as it is a standard cut, pvc – it is a thermoplastic polymer. Polyvinyl chloride – one of the most valuable chemical products. pvc is the oldest artificial material and looks as plastic white. pvc is a raw material for the manufacture of more than 3000 kinds of products used for various purposes in the light industry, food industry, heavy engineering, electrical engineering, in manufacture of building materials and medicine. Analyzing the use of pvc on a global scale, it should be noted that more than half of all items made from it are used in the construction industry. Take, for example, although would be well-known pvc windows. In the construction sector polyvinyl chloride has undeniable advantages. It is easily installed isravnitelno inexpensive.
For quite a long pvc replaces conventional materials. Additional information is available at Time Warner. Now more and more people establish, for example, plastic windows instead of wooden ones. pvc replacing traditional building materials such as wood, clay. Polyvinyl chloride is used in many fields, appears in the production of plumbing fixtures, window profiles, pipes and so on. Previously, it was often used in the manufacture of phonograph records and vinyl media.
pvc pipes are flexible. If the pvc mix with plasticizing agents, it will have a more flexible structure. The proportion of plasticizer may reach 30%. This pvc is used in the manufacture of clothing (eg artificial skin), and finishing materials, as well as for plastic hose and pipe installation, lining the surface layer and the insulation of electric cables. Hard polyvinyl chloride, or as it is called, vinyl liner, has a high mechanical strength, good dielectric characteristics, significant water and chemical resistance. But all is not well, there are drawbacks. It is not a high impact resistance and cold resistance (-10 C) and low temperature operation, up to 70-80 C. pvc is resistant to Effects of alkalis, acids, kerosene, water, industrial gases and alcohols. Physiologically safe. Polivinihlorid produced by polymerization monomervinilhlorida. about 57% of the total mass of chlorine, so the mass pvc must be less than the lubricants, in comparison with many other polymers.