Just-in-time preemptive single machine problem with costs of earliness/tardiness, interruption and work-in-process

This paper considers preemption and idle time are allowed in a single machine scheduling problem with just-in-time (JIT) approach. It incorporates Earliness/Tardiness (E/T) penalties, interruption penalties and holding cost of jobs which are waiting to be processed as work-in-process (WIP). Generally in non-preemptive problems, E/T penalties are a function of the completion time of the jobs. Then, we introduce a non-linear preemptive scheduling model where the earliness penalty depends on the starting time of a job. The model is liberalized by an elaborately–designed procedure to reach the optimum solution. To validate and verify the performance of proposed model, computational results are presented by solving a number of numerical examples

Technical Paper Production planning and worker training in dynamic manufacturing systems

a b s t r a c t Production planning is a vital activity in any manufacturing system, and naturally implies assigning the available resources to the required operations. This paper develops and analyzes a comprehensive mathematical model for dynamic manufacturing systems. The proposed model integrates production planning and worker training considering machine and worker time availability, operation sequence and multi-period planning horizon. The objective is to minimize machine maintenance and overhead, system reconfiguration, backorder and inventory holding, training and salary of worker costs. Computational results are presented to verify the proposed model

Investigating the protective effect of the methanolic extract of Salvia multicaulis on renal ischemia-reperfusion injuries in rats

In this research the protective effects of the methanolic extract of S. multicaulis was evaluated in renal ischaemia-reperfusion injuries in rats. 42 male rats were divided into 6 groups. In the treatment groups 1-3, before causing ischemia in the kidneys, rats received 50, 100, and 150 mg/kg/day doses of the extract orally for 20 days, then ischaemia was created. In the evaluation of urea and creatinine factor, rosmarinic acid and extract dose of 150 mg/kg/day had a significant effect in reducing these two factors