Simulation-based Optimized Production Policy for Hybrid MTS/MTO Glass Tube Manufacturing Systems

Glass Tube is one of the main components for fluorescent lamps as it contains all the other components to generate light. Glass tube industry faces a decline in demand in Egypt. This is attributed to two factors: currency floating and new lighting technologies. In response, glass tube manufacturers decided to diversify their products. This required the integration of Make-to-Stock (MTS), which is used usually for glass tube manufacturing, and Make-to-Order (MTO) which is used to fulfill demands for diversified products. In this thesis, Production policy is proposed to plan for MTS & MTO production. This policy determines when to produce broken glass (cullet), MTS product or MTO product. Priority is given to Cullet which is used as raw material in glass making. The second choice is to produce MTS product, and excess capacity is used to produce MTO products. Once MTO order is fulfilled, the choice is made to either produce cullet or MTS product. The policy defines two levels for cullet inventory and MTS product inventory. If cullet inventory reaches the lower level, cullet will be produced until the inventory level reaches higher level. If the cullet reaches the higher level or the level is decreasing towards lower level, products will be produced. The type of product is determined according to the inventory level of MTS product. If the MTS inventory level is lower than high inventory level, MTS product will be produced. Once it reaches high inventory level, MTO product will be produced. A simulation model is developed to simulate glass tube production. The model is divided into three interconnected modules: production, order fulfillment and decision. The model was verified and validated through different cases. Based on the simulation model, an optimization algorithm is applied to select optimum parameters for proposed policy with the objective of minimizing total costs. The proposed production policy proved its effectiveness in reducing total cost in glass tube manufacturing. Sensitivity analysis was performed to show the effect of raw material prices and energy price on the solutions obtained by optimization algorithm. Increase in raw material prices has effect on production parameters; however, it has no effect policy parameters. Increase in energy prices has effect on production parameters and policy parameters

Titrated oral misoprostol versus static regimen of oral misoprostol for induction of labour: a systematic review and meta-analysis

We aimed to conduct a systematic review and meta-analysis to compare the efficacy and safety of titrated oral misoprostol versus static oral misoprostol for labour induction. We searched for the available randomised clinical trials (RCTs) in the Cochrane Library, PubMed, ISI web of science, Scopus, and ClinicalTrials.gov. We included RCTs compared titrated oral misoprostol versus static regimen of oral misoprostol during labour induction. Our main outcomes were vaginal and caesarean delivery rates, uterine tachysystole, misoprostol side effects, and neonatal adverse events. Three RCTs met our inclusion criteria with a total number of 360 patients. The vaginal delivery rate did not significantly differ between both groups (p = 0.49). Titrated oral misoprostol was associated with significant increase in the caesarean delivery rate compared to static oral misoprostol (p = 0.04). Moreover, titrated oral misoprostol led to significant increase in the uterine tachysystole and misoprostol side effects (p = 0.01 & p = 0.003, respectively). There were no differences among both groups regarding different neonatal adverse events. In conclusion, titrated oral misoprostol increases the incidence of caesarean delivery, uterine tachysystole, and misoprostol side effects with a similar vaginal delivery rate compared to static dose misoprostol. Thus, static oral misoprostol should be used instead of titrated oral misoprostol during labour induction. Impact Statement What is already known on this subject? Different studies have evaluated titrated oral misoprostol administration for induction of labour and proved their efficacy in comparison with other induction methods. However, there is controversy among the published studies between titrated oral misoprostol and static oral misoprostol during induction of labour. A recent study concluded that hourly titrated misoprostol and static oral misoprostol are equally safe and effective when utilised for induction of labour with no fear of any adverse events. However, another study recommended static oral misoprostol administration for labour induction as it was linked to a lower caesarean section incidence, fewer drug side effects, and decline in complication rates in comparison with titrated oral misoprostol. What the results of this study add? Titrated oral misoprostol increases the incidence of caesarean delivery, uterine tachysystole, and misoprostol side effects with a similar vaginal delivery rate compared to static dose misoprostol. What the implications are of these findings for clinical practice and/or further research? Static oral misoprostol should be used instead of titrated oral misoprostol during labour induction. More future trials are required to confirm our findings