سؤال قراءة ستيب محلول — المفردات في السياق (تدريب 6111)

(1) Expanded polystyrene (or “Styrofoam”) is an excellent insulator. That’s why it’s a popular material for insulating buildings—and why those cheap little cups of deli coffee still burn your tongue after 30 minutes. But its environmental record leaves something to be desired. It’s non-biodegradable, harmful to animals who accidentally eat it and made from potential carcinogens or cancer-causing chemicals. (2) Researchers at the University of Maryland have developed a super-lightweight insulating material they say could prove to be a better, more eco-friendly alternative. The material, made from tiny wood fibers, is called Nano wood. It blocks heat at least 10 degrees better than Styrofoam or silica aerogel, a common insulator, and it can take a least 30 times more pressure than 45n crushed. (3) Working in the lab of materials scientist Liang Bing Hu. postdoctoral researcher Tain Li is the lead author on the study, published in the journal science Advances. (4) Hu and his team had been working on Nano cellulose, the Nano-sized version of the fibrous material that makes plants and trees rigid. Nano cellulose has an impressive strength-to-weight ratio, about eight times greater than of steel. (5) For the Nano wood, the team removed the lignin, the polymer that holds the cells of wood together Removing the lignin, a heat conductor. gave the resulting product powerful capabilities. It also turned the product white which means it reflects light. The think Nano wood has enormous potentials as a green, material. Using it could potentially «save billion» in energy costs says Li. What is one negative effect of Styrofoam?