Jon C. Liebman

Mathematical analysis of emergency ambulance location

Abstract Proper ambulance location is crucial in saving lives and reducing injury. To determine efficient and effective locations, it is necessary to evaluate both the spatial and temporal distributions of demand. Because of the complex nature of the ambulance response and transport activities, the problem is subdivided into a facility location problem and a vehicle allocation problem. A set covering model is modified to solve the location problem while a simulation is used to solve the allocation problem. Combining these two models provides a powerful methodology for systematically finding a satisfactory solution to the ambulance location problem.

Energy from refuse by bioconversion, fermentation and residue disposal processes

Biological conversion of organic refuse to methane by anaerobic fermentation is one mechanism by which the energy in urban waste can be reclaimed. Laboratory studies have been used to determine the rate and quantity of gas production at various operating temperatures. The dewatering characteristics of the spent fermentation slurry have been evaluated. The spent solids can be dewatered to a sufficiently low moisture content such that incineration is self-sustaining. The incineration system has been evaluated to determine the possible energy recovery from the spent cake. A process for treating the liquid blowdown from the system has been developed. A mathematical simulation of the total system has been constructed to evaluate performance under various operating conditions. The operating cost of the system can be obtained. A plant processing 908 metric tons of refuse per day will produce 3905 m/sup 3/ of methane per hour. If the methane is marketed for

Evaluating environmental quality management programmes in which dischargers are grouped

3.53/100 m/sup 3/, the system will require a dump fee for refuse disposal in excess of

Battle of the Network Models: Epilogue

5.34/metric ton. Sale of recovered steam from the incineration of the spent cake can reduce the dump fee by about

The optimal allocation of stream dissolved oxygen

3.00. Recovery of just methane provides an efficiency of energy recovery of 32.6 percent. Thismorexa0» efficiency can be increased to 63.4 percent if the steam from the incinerator can be sold.«xa0less

Comment on ‘Design of optimal water distribution systems’ by E. Alperovits and U. Shamir

Abstract A method is presented for evaluating management programmes in which the dischargers are divided into groups. Analogous non-linear mathematical formulations are presented for direct regulation and effluent charge programmes, and a non-linear branch-and-bound solution procedure is described. A detailed algorithm is described for the effluent charge case; it is shown to be very practical in an application to data for the Delaware estuary.