Cosi ( COSI) said Tuesday that Kevin Armstrong was named the company's president and chief executive, effective immediately. Armstrong replaces interim CEO Jay Wainwright, who is also a founder of the company. Wainwright, who replaced co-founder Andy Stenzler when he resigned on Feb. 3, will continue to work with the company, New York-based Cosi said. Most recently, Armstrong was president and chief operating officer of Long John Silver's Restaurants. Shares of Cosi closed at $1.77 Monday on the Nasdaq.