Optimal production control of a dynamic two-product manufacturing system with setup costs and setup times

This paper deals with the optimal control of a one-machine two-product manufacturing system with setup changes, operating in a continuous time dynamic environment. The system is deterministic. When production is switched from one product to the other, a known constant setup time and a setup cost are incurred. Each product has specified constant processing time and constant demand rate, as well as an infinite supply of raw material. The problem is formulated as a feedback control problem. The objective is to minimize the total backlog, inventory and setup costs incurred over a finite horizon. The optimal solution provides the optimal production rate and setup switching epochs as a function of the state of the system (backlog and inventory levels). For the steady state, the optimal cyclic schedule is determined. To solve the transient case, the system's state space is partitioned into mutually exclusive regions such that with each region, the optimal control policy is determined analytically.     

Phenomenological πN→ππN amplitude and the modelling of the Olsson–Turner and Chew–Low approaches

The phenomenological amplitude for the reaction πN→ππN fixed by fittings to the experimental data in the energy region 0.300 ≤P _Lab≤ 500 MeV/c is used for modelling the Chew–Low extrapolation and Olsson–Turner threshold approach. It is shown that the uncritical application of the former results in enermous theoretical errors, the extracted values being in fact random numbers. The results of the Olsson–Turner method are characterized by significant systematic errors coming from unknown details of the isobar physics. Received: 10 December 1997     

Cardinal hermite interpolation with box splines II

Summary In the present work we extent the results in [RS] on CHIP, i.e. Cardinal Hermite Interpolation by the span of translates of directional derivatives of a box spline. These directional derivatives are that ones which define the type of the Hermite Interpolation. We admit here several (linearly independent) directions with multiplicities instead of one direction as in [RS]. Under the same assumptions on the smoothness of the box spline and its defining matrixT we can prove as in [RS]: CHIP has a system of fundamental solutions which are inL L ² together with its directional derivatives mentioned above. Moreover, for data sequences inl ^p ( ^d ), 1p2, there is a spline function inL ^p, 1/p+1/p=1, which solves CHIP.Research supported in part by NSERC Canada under Grant # A7687. This research was completed while this author was supported by a grant from the Deutscher Akademischer Austauschdienst     

Biosynthesis of desosamine: construction of a new macrolide carrying a genetically designed sugar moiety

[formula: see text] The appended sugars in macrolide antibiotics are indispensable to the biological activities of these important drugs. In an effort to generate a set of novel macrolide derivatives, we have created a new analogue of methymycin and neomethymycin, antibiotics produced by Streptomyces venezuelae. This analogue 15 carrying a different sugar, D-quinovose, instead of D-desosamine, was constructed by taking advantage of targeted gene deletion combined with a specific pathway-independent C-3 reduction capability of the wild type S. venezuelae.     

ALKALINE QUENCHING OF BACTERIORHODOPSIN TRYPTOPHANYL FLUORESCENCE: EVIDENCE FOR AQUEOUS ACCESSIBILITY OR A HYDROGEN-BONDED CHAIN

Abstract— Comparison between Trp fluorescence yields of membrane-bound bacteriorhodopsin (BR) and retinylidene-free bacterioopsin (BO) is consistent with a model in which all eight Trp residues are active fiuorophores in the latter, while the emission of all but two residues in the former is lost by energy transfer to retinal. The visible chromophore of BR is progressively bleached with increasing pH. Up to pH 12 this bleaching is reversed on reneutralization; but above this the change is irreversible with the appearance of a new absorption band characteristic of free retinal. Emission yields for both proteins decrease with increasingly alkaline pH in a manner typical of energy transfer to weakly-fluorescent tyrosinate. The limiting yields, reached at a pH corresponding to that producing irreversible bleaching of the visible chromophore, agree with an integral value of one remaining active Trp fluorophore in BR and between one and two in BO and show that the bulk of Trp are within the 11 Å Förster energy-transfer distance of Tyr accessible to OH⁻. Current models of the native protein structure of BR arrange the polypeptide chain primarily in a bundle of seven helical segments with axes perpendicular to the lipid bilayer plane and with buried polar residues, including Trp and Tyr, located at intrahelical surfaces. An interpretation of the observed accessibility of buried Tyr to OH⁻ is that an aqueous region exists within the protein structure. Moreover, this putative aqueous region must be close to the retinylidene chromophore and thus may be associated with the light-driven ion transport system. The results are also compatible with energy transfer to internal Tyr residues which are connected via a chain of phenolate hydrogen bonds to a surface Tyr.