Optimisation of maintenance and production in multipurpose plants.

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Optimisation of maintenance and production in multipurpose plants

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An age reduction approach for finite horizon optimization of preventive maintenance for single units subject to random failures

We consider a single unit working in a continuous mode of operation characterized by an increasing failure rate. We determine the optimal number of preventive maintenance activities to be scheduled within a time horizon of interest, the required extent of the preventive maintenance by means of an age reduction of the unit and the corresponding optimal value of the expected profit. We assume that any breakdown occuring is minimally repaired, the repair is performed instantaneously, and the repair cost is the same for any repair. On the other hand, the cost associated with a preventive maintenance activity may vary as well as its duration. (C) 1998 Elsevier Science Ltd. All rights reserved

Repeated phlebotomies improve and stabilise renal function in cyanotic nephropathy

Patients over 10 years of age with cyanotic congenital heart disease (CCHD) risk developing significant glomerular proteinuria, a condition called cyanotic nephropathy. Even though the pathogenesis of glomerulopathy associated with CCHD is still unclear, a potential mechanism is hyperviscosity-induced decrease in peritubular capillary blood flow leading to an increase in glomerular capillary pressure, in turn resulting in proteinuria. Although angiotensin-converting enzyme (ACE) inhibitors have been traditionally used in the treatment of these patients with cyanotic nephropathy, they may, however, not be well tolerated. Here we present a case of an adult patient with CCHD who could not tolerate an ACE inhibitor but showed improvement and stabilisation of her renal function following treatment with repeated phlebotomies