Compulsory voting papers. Compulsory voting is increasingly resented by citizens in some countries such as Brazil, the largest country where compulsory voting is enforced: at the last presidential election in 2014, some 30 million voters, about 21% of registered voters, did not vote, despite the fact that Brazil has some of the most severe penalties enforced against non voters. A study of a Swiss canton where compulsory voting was enforced found that compulsory voting significantly increased electoral support for leftist policy positions in referenda by up to 20 percentage points. Another study found that the effects of universal turnout in the United
Catalytic converter is maintained. Three-way catalytic converters can store oxygen from the exhaust gas stream, usually when the air–fuel ratio goes lean. When sufficient oxygen is not available from the exhaust stream, the stored oxygen is released and consumed "(see cerium(IV) oxide)". A lack of sufficient oxygen occurs either when oxygen derived from reduction is unavailable or when certain maneuvers such as hard acceleration enrich the mixture beyond the ability of the converter to supply oxygen. Unwanted reactions can occur in the three-way catalyst, such as the formation of odoriferous hydrogen sulfide and ammonia. Formation of each can be limited by modifications