An energy absorbing and displacing structure for athletic protective equipment, such as an athletic shin-guard, is provided using a flexible web-shaped body to hold a rigid band-shaped member in place. A method of gravel packing with a viscoelastic surfactant-based carrier fluid by laying down a filter cake at least a portion of which is a base-soluble material, injecting gravel, and causing hydrolysis and dissolution of the solid base-soluble material by adding base. The method is implemented in software form and generates pressure and thrust versus time data at a selected temperature. A piston is connected to the mover of the motor. A maximum voltage value is recorded before a first decrease in the actual voltage change of the under-test lithium ion battery during the over charging. A cover having indicia is attached to the cap permitting writing, symbols, designs and the like to be displayed.