Types of check valves. A ball check valve is a check valve in which the closing member, the movable part to block the flow, is a spherical ball. In some ball check valves, the ball is spring-loaded to help keep it shut.
(October 2016) Learning is the act of acquiring new, or modifying and reinforcing existing, knowledge, behaviors, skills, values, or preferences which may lead to a potential change in synthesizing information, depth of the knowledge, attitude or behavior relative to the type and range of experience.
XY = 100X1-.322 = 100X.678. An 80 percent learning curve means that the cumulative average time (and cost) will decrease by 20 percent each time output doubles. In other words, the new cumulative average for the doubled quantity will be 80% of the previous cumulative average before output is doubled.