In the formal language of economics, X and Y are substitutes if the demand for X increases when the price of Y increases, or a positive cross elasticity of demand.
Potting mix is the material that goes into a garden pot before you put seeds and plants into it. 1  It keeps the plant in place. 2  It holds water for the plantâs roots to soak up.  It contains nutrients that feed the plant.
Shotcrete is the spraying of concrete onto a receiving surface at high velocity. This is achieved by conveying the concrete through a hose where compressed air or water is added at a nozzle attached to a hose end. There are 2 methods of shotcrete.The wet mix method and the dry mix method. In the wet mix method, low slump ready mixed concrete is pump through a hose where air is added at a nozzle.In the dry mix method, cementitious material is veyed by an air steam where water is introduced at the point of discharge.he wet mix method and the dry mix method. In the wet mix method, low slump ready mixed concrete is pump through a hose where air is added at a nozzle. In the dry mix method, cementitious material is veyed by an air steam where water is introduced at the point of discharge.