An average of 65 percent of children aged between 8 and 11 have their own smartphone in the U.K. according to a survey by Internet Matters. That survey also found that the majority of parents would like a minimum age for smartphone ownership in the U.K. to be set at age 10. However, some kids are using smartphones from a very young age. One study by the American Academy of Pediatrics that focused on children in an urban, low-income, minority community suggested that almost all children (96.6 percent) use mobile devices and that 75 percent have their own mobile device by the age of four.
A cyclic acetal is an acetal in which the acetal carbon and one or both oxygen atoms are members of a ring. An acetal is a compound that contains two ether groups on the same carbon atom. If the two OH groups are part of a 1,2- or a 1,3-diol, the product is a cyclic acetal. The video below describes how a cyclic acetal is formed from a diol. The purple #color(purple)(O)# atom in the hemiacetal intermediate is held close to the hemiacetal carbon, so the intramolecular ring-closing reaction is fast.
DelrinÂ® is a homo-polymer Acetal produced by Dupont. The generic Acetal covers both the homo-polymer DelrinÂ® and the co-polymer grades of resin. Both materials meet the ASTM-D-4181, ASTM-D-6100 or ASTM-D-6778 specification (an old call out is L-P-392).