Complex sentence: Convergent Scientific, Inc. (CSI) is an American company founded in December 2010 and based in Huntington Beach, California, which has an effort to build a small-scale polywell fusing deuterium.
Split into simpler sentences: Convergent Scientific, Inc. (CSI) is an American company founded in December 2010 and based in Huntington Beach, California. They now has an effort to build a small-scale polywell fusing deuterium.