<div class="htmlview paragraph"><b>I</b>F a piston ring is to remain an effective seal over a long period of time, despite heat, pressure, corrosion, friction, and abrasion, it must be made from the proper material and it must be of the proper design.</div> <div class="htmlview paragraph">Mr. Smith discusses here both of these aspects of the problem.</div> <div class="htmlview paragraph"> <div class="graphic-wrapper"><img class="article-image" src="450214_fig0001.jpg" alt="No Caption Available"/></div></div>