The first day of school in the China falls on 1 September, or the first Monday following if September 1 is a Friday, Saturday, or Sunday. In northeastern China, schools open on Monday in mid-August after summer vacation.
3) Improper heating profiles setting lead to unbalanced heating zones temperature inside heating furnace, which causes uneven glass temperature on both different parts of the glass sheet and between the top and bottom glass surfaces, thus may brings irregular white haze on glass surfaces.
Or, maybe, the nodules of glass that can form when lighting goes to ground through sand. In any event, glass is made by â¦ heating sand until it melts. Actually, the sand particles have to be separated first. If you just melted sand you would get a dark, non-transparent glass. You have to find the clear crystals in the sand to make glass.