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ABSTRACTIn this paper, we study integrated strategies joining maintenance and quality. We consider an imperfect manufacturing system composed of a single machine subject to an increasing random failure rate and producing conforming (first and second choice) and non conforming items. In order to decrease the failure rate and its impact on teh quality of output products, a preventive maintenance (PM) policy, block type, with minimal reapair is applied. Indeed, two different strategies are developed: The first strategy consists on selling top quality products at the best price, selling products with substandard quality at a lower price and rejecting non-conforming items. For the second strategy, we propose reworking activities for products with substandard quality and non-conforming items in order to be sold at the best price. We aim to establish the optimal number of batches produced N* before each PM action maximizing the total profit per time unit. These two strategies are studied for both an infinite and finite horizon. A comparative study between these two strategies for an infinite horizon is developed in order to identify the most economical strategy. Numerical and sensitivity studies are developed, inspired from an industrial case, in order to illustrate the proposed models.

Past attempts to develop electronic laboratory notebooks (ELN) have not always met with the success expected of them. This may have been due to job aspects and the difficulties encountered in their practical application, insufficient support provided to users during the learning phase, application complexity, interfacing problems with preexisting information systems, and the necessary integration of regulatory and legal aspects. Sanofi-Synthelabo adopted a different approach by emphasizing practical application and user support while putting the regulatory aspects to one side. An ELN model was developed on the basis of initial user-derived specifications, and a prototype was then produced, known as Kalabie (Klee business software). This ELN is sufficiently flexible to be shaped for different specialized chemical development sectors (synthesis, automates, preparative chromatography) and interfaces with preexisting in-house Oracle and MDL databases, thus supporting multisite extensions as a user-friendly intranet application. Technicians, scientists, and managers were happy with Kalabie when it entered service. Work is ongoing to extend the use of the ELN and to integrate the regulatory aspects.

The shapes of the C22H46-C24H50and C23H48-C24H50binary phase diagrams were analyzed. In the C22H46-C24H50binary system the increased stability of the binary compounds with increasing temperature can be explained by the much larger heat capacity and entropy of the binary compounds compared to that of the components C22H46and C24H50. In the C23H48-C24H50system this effect is much less pronounced. The measured enthalpy data of n-alkanes C19H40to C24H50and of the binary system C22H46-C24H50were analyzed to obtain the ‘excess’ heat capacity per atom of carbon {[Cp/(Rm)]-3} (Rmbeing the number of carbon atoms). The ‘excess’ heat capacity per carbon atom is the value of the heat capacity above the Debye high temperature value of 3R. At low temperatures (below 280 K) one is in the Debye temperature θDregion. At higher temperatures the large ‘excess’ heat capacity of the solids explains the movements in the carbon chains. In the liquid the excess heat capacity is small and corresponds numerically to the anharmonic vibrations in low melting metals. In contrast to metals, where the difference in heat capacity between liquid and solid below the melting point is positive Cp(L-s)>0, in the alkanes studied it is strongly negative Cp(L-s)≪0. This explains the shape of the binary phase diagrams C22H46-C24H50, C24H50-C26H54, C22H46-C23H48and C23H48-C24H50.