It is desired to produce and aligned carbon fiber-epoxy matrix composite having a longitudinal tensile strength of 72,500 psi. calculate the volume fraction of fibers necessary if (a) the average fiber diameter and length are .01 and.05 mm respectively (b) the fiber fracture strength is 580,000 psi. (c) the fiber matrix bond strength is 3625 psi and the matrix stress at composite failure is 1,000 psi.

An external consultant recommends that a plant installs a bank of capacitors for power factor correction. this will reduce the peak electrical demand charges by an average of 93 kw every month. the plant current pays $13 per kw in peak demand charges. the capacitor bank will include 223 kw of fixed capacitors, and 183 of variable capacitors. the fixed capacitors cost $59 per kw, and the variable capacitors will cost $65 per kw. the consultant charges 21% of the equipment costs to install the capacitors. because this project will reduce the demand for the electric utility, they are prepared to provide a one-time rebate of $42 per kw of reduced demand. what is the simple payback period for this project (in years)?