A data-driven approach to multi-product production network planning

The clearing function models the non-linear relationship between work-in-process and throughput and has been proposed for production planning in environments with queuing (congestion) effects. One approach in multi-product, multi-stage environments has been to model the clearing function at the bottleneck machine only. However, since the bottleneck shifts as the product release mix changes, this approach has its limitations. The other approach is the Alternative Clearing Function formulation, where the clearing function is first estimated at the resource level using piecewise linear regression from simulation experiments, and then embedded into a linear programme. This paper develops an alternative to the Allocated Clearing Function formulation, wherein system throughput is estimated at discrete work-in-process points. A mixed integer programming formulation is then presented to use these throughput estimates for discrete release choices. The strength of the formulation is illustrated with a numerical example and the new approach is compared with the ACF.     

Tuning the photocatalytic activity of TiO2 by Ag loading: Experimental and modelling studies for the degradation of amlodipine besylate drug

In this research work, a heterogeneous photocatalytic process has been adopted for emergent pharmaceutical effluents treatment using amlodipine besylate as a contaminant molecule and Ag–TiO₂ as a nanocatalyst. The influence of amlodipine besylate initial solution pH and concentration, Ag doping content, catalyst mass, and contact time has been investigated. The obtained results indicate that Ag doping induces rutile-anatase phase transformation and improved the surface characteristics (higher surface area and larger average pore volume). The photodegradation of amlodipine besylate is very effective; the highest performance is found to be 100% for 1% doped TiO₂ nanocatalyst under optimum conditions (pH 6, 0.5 g L^-1 catalyst content, 100 min). The experimental data of the photodegradation process are found to obey the Lagergren kinetic model. Besides, the overall reaction rate is most likely governed by the intra-particular mass diffusion of amlodipine besylate, regardless of the process experimental conditions.