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When faced with a medical problem, patients contact their primary care physician (PCP) first. Here mainly two types of patient requests occur: non-scheduled patients who are walk-ins without an appointment and scheduled patients with an appointment. Number and position of the scheduled appointments influence waiting times for patients, capacity for treatment and the utilization of PCPs. As the number of patient requests differs significantly between weekdays, the challenge is to match capacity with patient requests and provide as few appointment slots as necessary. In this way, capacity for walk-ins is maximized while overall capacity restrictions are met. Decisions as to the optimal appointment capacity per day on a tactical decision level has gained little attention in the literature. A mixed integer linear model is developed, where the minimum number of appointments scheduled for a weekly profile is determined. We are thus able to give the answer as to how many appointments to offer on each day in a week in order to create a schedule that takes patient preferences as well as PCP preferences into account. Appointment schedules are often influenced by uncertain demands due to the number of urgent patients, interarrivals and service times. Based on an exemplary case study, the advantages of the optimal appointment schedule on different performance criteria are shown by detailed stochastic simulations.

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The free-radical terpolymerization of maleic anhydride (MSA), isobutyl vinyl ether (VIBE) and anethol (ANE) at 60°C is described. These three monomers do not homopolymerize under the conditions used. Binary copolymers are only obtained from MSA and one of the two investigated donor monomers, whereas the binary copolymerization of VIBE with ANE is not possible. In all terpolymers from these three non-homopolymerizable monomers the MSA content amounts to about 50 mol-%; VIBE is about twice as reactive as ANE. The terpolymerization can formally also be described under the assumption that two binary complexes (MSNANE (I) and MSANIBE (11)) are copolymerized. For this case the reactivity ratios rl = 0,9 and r,, = 1,7 are obtained.

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