Combining maintenance activities in an operational Planning Phase: a Set-Partitioning approach

Joint execution of maintenance activities can redua costs becausepreparative activities, like opening a machine, may be shared.Combining execution, however, also implies that activities arecamed out at times other than originally planned. In this paper,we analyse the problem of determining which activities shouldbe combined at which moments in time. We develop a methodologyto represent the cost-effectiveness of combining activities,and to identify an optimal combination plan. The method consistsof three phases: one in which penalty cost functions are derived,another in which combinations are evaluated, and finally onein which the optimal combination is obtained through a set-partitioningalgorithm.     

INVESTIGATIONS ON VINYLENE CARBONATE Ⅰ. PREPARATION AND PROPERTIES OF POLY-(VINYLENEC ARBONATE)

Bulk polymerization of vinylene carbonate using t-butylperoxypivalate at 40℃gave colourless, high molecular weight poly(vinylene carbonate) (PVCA). Solutions of PVCA in acetone and DMF are not stable at 25℃and this degradation was studied. From measurements in DMF with unfractionated PVCA a Mark-Houwink equation was obtained: