Soldering (see RoHS), has led to a change in formulation of both solders and fluxes. Water-soluble non-rosin-based fluxes have been increasingly used since the 1980s so that soldered boards can be cleaned with water or water-based cleaners. This eliminates hazardous solvents from the production environment, and from factory effluents. Those regulations have also reduced the use of lead based solders, and caused the melting temperatures of solders in use to increase by up to . "Hot-bar reflow" is a selective soldering process where two pre-fluxed, solder coated parts are heated with heating element (called a thermode) to a sufficient temperature to
Hard and soft C or an alveolo-palatal , and occurs before not only , and , but also , , and . Another similar system with hard and soft is found in Faroese with the hard being and the soft being , and Turkish where the soft is . The Vietnamese alphabet does not have a hard or a soft per se. However, since it was inherited from European languages, the letter never occurs in "soft positions", i.e. before , and where is used instead, while never occurs elsewhere except in the digraph and a few loanwords. Hồ Chí Minh had proposed a simplified