This paper presents big-M (penalty) method for optimum time coordination of overcurrent (OC) relays. The method is based on the simplex algorithm which is used to find optimum solution of linear programming problem (LPP). The method introduces artificial variables in the objective function to get an initial basic feasible solution (IBFS). Artificial variables are removed using iterative process...

today the industrial wastes are one of the main problems in the developing countries. discharging the industrial wastewater into environment is harmful for human health and other living creatures.thus decreasing of the pollution load of waste waters is an important environmental issue.adsorption of chemical oxygen demand by biomass wastes can be a proper and low cost method for cod removal from...

fridges are used in various industries, and heat exchanger is one of the main components of these systems; therefore, efficiency analysis of these systems is very important. in many fridges, frost over the heat exchanger tubes or pipes affects the system operation and reduces heat transfer between the refrigerant and ambient, so defrosting systems are usually used to enhance heat transfer. desi...