To make white sugar, sulfur dioxide is added to cane juice before it gets evaporated. This gas does the bleaching of the juice so that it does not turn brown and produces white sugar. At later stages, phosphoric acid, calcium hydroxide or carbon dioxide is added to absorb impurities.
The first REM sleep period usually occurs about 70 to 90 minutes after we fall asleep. A complete sleep cycle takes 90 to 110 minutes on average. The first sleep cycles each night contain relatively short REM periods and long periods of deep sleep.
The typical person will experience five stages of sleep each night. It takes approximately 90 minutes to pass through all five stages of sleep. According to my mathematics, if a typical person has roughly 8 hours of sleep, then they should also experience five cycles of sleep. That being said, not everyone will experience the same sleeping pattern.