Maintenance Strategy Choice Supported by the Failure Rate Function: Application in a Serial Manufacturing Line

The purpose of this article is to choose a maintenance procedure for the critical equipment of a forging production line with five machines. The research method is quantitative modelling and simulation. The main research technique includes retrieving time between failure and time to repair data and find the most likely distribution that has produced the data. The most likely failure rate function helps to define the maintenance strategy. The study includes two kinds of maintenance policies, reactive and anticipatory. Reactive policies include emergency and corrective procedures. Anticipatory policies include predictive and preventive ones combined with a total productive maintenance management approach. The most suitable combination for the first three machines is emergency and corrective choice. For the other machines, a combination of total productive maintenance and a predictive approach is optimal. The study encompasses the case of a serial production manufacturing line and maximum likelihood estimation. The failure rate function defines a combination of strategies for each machine. In addition, the study calculates the individual and systemic mean time to failure, mean time to repair, availability, and the most likely number of failures per production order, which follows a Poisson process. The main contribution of the article is a structured method to help define maintenance choices for critical equipment based on empirical data

Research requirements to reduce maintenance costs of civil helicopters

The maintenance problems faced by the operators of civil helicopters that result in high costs are documented. Existing technology that can be applied to reduce maintenance costs and research that should be carried out were identified. Good design practice and application of existing technology were described as having a significant impact on reducing maintenance costs immediately. The research and development that have potential for long range reduction of maintenance costs are presented

Beyond CD19: Opportunities for Future Development of Targeted Immunotherapy in Pediatric Relapsed-Refractory Acute Leukemia

Chimeric antigen receptor (CAR) T cell therapy has been used as a targeted approach in cancer therapy. Relapsed and refractory acute leukemia in pediatrics has been difficult to treat with conventional therapy due to dose limiting toxicities. With the recent success of CD 19 CAR in pediatric patients with B cell ALL, this mode of therapy has become a very attractive option for these patients with high risk disease. In this review, we will discuss current treatment paradigms of pediatric acute leukemia, and potential therapeutic targets for additional high risk populations, including T cell ALL, AML, and infant ALL

MICROELECTRONICS PACKAGING TECHNOLOGY ROADMAPS, ASSEMBLY RELIABILITY, AND PROGNOSTICS

This paper reviews the industry roadmaps on commercial-off-the shelf (COTS) microelectronics packaging technologies covering the current trends toward further reducing size and increasing functionality. Due tothe breadth of work being performed in this field, this paper presents only a number of key packaging technologies. The topics for each category were down-selected by reviewing reports of industry roadmaps including the International Technology Roadmap for Semiconductor (ITRS) and by surveying publications of the International Electronics Manufacturing Initiative (iNEMI) and the roadmap of association connecting electronics industry (IPC). The paper also summarizes the findings of numerous articles and websites that allotted to the emerging and trends in microelectronics packaging technologies. A brief discussion was presented on packaging hierarchy from die to package and to system levels. Key elements of reliability for packaging assemblies were presented followed by reliabilty definition from a probablistic failure perspective. An example was present for showing conventional reliability approach using Monte Carlo simulation results for a number of plastic ball grid array (PBGA). The simulation results were compared to experimental thermal cycle test data. Prognostic health monitoring (PHM) methods, a growing field for microelectronics packaging technologies, were briefly discussed. The artificial neural network (ANN), a data-driven PHM, was discussed in details. Finally, it presented inter- and extra-polations using ANN simulation for thermal cycle test data of PBGA and ceramic BGA (CBGA) assemblies

Trends in the Statistical Assessment of Reliability

Changes in technology have had and will continue to have a strong effect on changes in the area of statistical assessment of reliability data. These changes include higher levels of integration in electronics, improvements in measurement technology and the deployment of sensors and smart chips into more products, dramatically improved computing power and storage technology, and the development of new, powerful statistical methods for graphics, inference, and experimental design and reliability test planning. This paper traces some of the history of the development of statistical methods for reliability assessment and makes some predictions about the future

Decision support tools for preventive maintenance intervals and replacement decisions of engineering assets

Prognostic models for maintenance decisions have inherent limitations due to quality quantity of historical data, assumptions made, and time required in validating models. In this paper, Preventive Maintenance (PM) Intervals, Failure events, cost and maintenance records from Computerized Maintenance Management System (CMMS) are analyzed for reducing downtimes and Operating Expenditure (OPEX). The proposed methodologies for maintenance intervals and replacements with acceptable level of confidence are articulated to asset maintenance of a City Council of Australian Local Government organisation as a case of improved decision making under limited information.IEEE International Conference on Industrial Engineering and Engineering Managemen

The role of real-time ultrasound in the assessment and management of preterm labour

In this thesis the use of real-time ultrasound in the assessment and management of preterm labour has been studied, with particular reference to the observation of fetal breathing movements, gross fetal body movements and the state of the uterine cervix. In addition, a longitudinal analysis of the trends in preterm labour in the John Radcliffe Hospital in Oxford between 1973 and 1981 has been performed. Finally, an attempt has been made to clarify the relationship between prostaglandin E2 and fetal breathing movements. The analysis of the trends in preterm labour in Oxford has shown that the incidence of preterm delivery remains unaltered. Of these patients, however, those eligible for tocolytic therapy (unexplained spontaneous preterm labour) form a small proportion. The incidence of extreme prematurity in this group is very low and the neonatal outcome is good. The presence or absence of Fetal Breathing Movements (FBM) by defined criteria is shown to be a highly sensitive index of whether the preterm labour is going to progress to delivery or not in singleton pregnancies with intact membranes. Its significance is lost when the membranes are ruptured and in multiple pregnancies. In pregnancies complicated by antepartum haemorrhage the presence or absence of Fetal Breathing Movements does not predict further haemorrhage leading to delivery. Fetal Breathing Movement status on admission bears no relationship to neonatal outcome and gives no indication of the presence of intrauterine infection. Silent chorioamnionitis has been highlighted as an important cause of "unexplained" preterm labour. Gross Fetal Body Movements (FM) are shown to give no early indication of impending preterm delivery. Evidence is presented to suggest that significant diminution in Fetal Movements is related to poor neonatal outcome. Ultrasonic measurement of the uterine cervix has been found to be technically feasible but of no benefit in the diagnosis of ongoing preterm labour. The relationship between prostaglandin E2 (PGE2) and the cessation of fetal breathing movement has been approached by elucidating the maternal absorption of PGE2 from a vaginal pessary. This then enabled me to sample fetal blood at the time of maximal maternal concentrations (the time we expect the fetal concentration to be greatest). This was performed by fetoscopy and demonstrated that a significant rise in fetal bicycleprostaglandin-E-metabolite (bicyclo-PGEM) occurs following maternal vaginal administration of PGE2. Using this information FBM has been assessed two and a half hours following the vaginal administration of PGE2. Although inconclusive, no reduction in FBM was demonstrated. as the bicyclo-PGE metabolite is used to assess PGE levels, this evidence decreases the probability that PGE mediates the reduction in FBM with the onset of labour