We can perhaps state the basic ecological objectives of mechanical engineering
design rather simply: (1) to utilize materials so that they are economically recyclable
within reasonable time periods without causing objectionable air, ground and
water pollution and (2) to minimize the rate of consumption of nonrecycled energy
sources (such as fossil fuels) both to conserve these resources and to minimize thermal
pollution. In some instances, the minimization of noise pollution is also a factor
to be considered.
As with safety considerations, ecological factors are much more difficult for the
engineer to tie down than are such matters as stress and deflection. The following is
a suggested list of points to be considered.