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.
â¢ The scope of this project is to make a process design, technical and economical feasibility. study for the production of polyethylene terephthalate by direct esterification of terephthalic. acid and ethylene glycol using membrane reactor technology to remove the esterification by-. product, which is water.