Dr Laks says â[e]ven were the regression line to have a slope of zero, if the SD of the duct diameter increases as a function of time, then the upper limit of normal value would increase with age.â There is no indication that the variance increases with age.
PET, which stands for polyethylene terephthalate, is a form of polyester (just like the clothing fabric). It is extruded or molded into plastic bottles and containers for packaging foods and beverages, personal care products, and many other consumer products.ET is a polymer of ethylene glycol and terephthalic acid. Pellets of PET resin are heated to a molten liquid, which can be easily extruded or molded into almost any shape. PET was first synthesized in the U.S. during the mid-1940s by DuPont chemists searching for polymers that could be used to make new textile fibers.
PET is polyethylene terephthalate. It's a plastic resin and the most common type of polyester. Two monomersâmodified ethylene glycol and purified terephthalic acidâare combined to form the polymer called polyethylene terephthalate.PET was discovered and patented in England in 1941.ET is the plastic labeled with the #1 code. Many beverages, food items and other consumer products are delivered in bottles or packages made from PET. The #1 code is usually found on or near the bottom of the container. Up to 100% of a PET package can be made from recycled PET.