Many NOx sensors work by first removing oxygen and then breaking down the nitrogen oxides to provide a reading. However, the NexTech sensor eliminates the need to remove oxygen; the sensor material is engineered to have a strong NOx sensitivity even in the presence of oxygen.
Sour beers are probably the oldest style of brew in the world, but they're just starting to get popular in the States. They were all the buzz at this year's Great American Beer Festival. And with hundreds of brewers now dabbling in sours, it's easier than ever to find them at a local bar or grocery store.
Sour cream is a dairy product obtained by fermenting a regular cream with certain kinds of lactic acid bacteria. The bacterial culture, which is introduced either deliberately or naturally, sours and thickens the cream. Its name stems from the production of lactic acid by bacterial fermentation, which is called souring.