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.
Received 12 April 2003; accepted 30 June 2003. Abstract. Blends of poly(trimethylene terephthalate) (PTT) and poly(butylene terephthalate) (PBT) were miscible in all of the. blend compositions studied, as evidenced by an observed single and composition-dependent glass transition temperature. for each blend composition. The variation of the glass transition temperature with the blend composition was well. predicted by the GordonâTaylor equation, with ï¬tting parameter being ca. 6.9.