Models for capacitated lot-sizing problem with backlogging,setup carryover and crossover

Setup operations are significant in some production environments. It is mandatory that their production plans consider some features, as setup state conservation across periods through setup carryover and crossover. The modelling of setup crossover allows more flexible decisions and is essential for problems with long setup times. This paper proposes two models for the capacitated lot-sizing problem with backlogging and setup carryover and crossover. The first is in line with other models from the literature, whereas the second considers a disaggregated setup variable, which tracks the starting and completion times of the setup operation. This innovative approach permits a more compact formulation. Computational results show that the proposed models have outperformed other state-of-the-art formulation.     

Stability and convergence of the spectral Lagrange-Galerkin method for mixed periodic/non-periodic convection-dominated diffusion problems

We present a convergence analysis of the spectral Lagrange-Galerkinmethod for mixed periodic/non-periodic convection-diffusionproblems. The scheme is unconditionally stable, independentof the diffusion coefficient, even in the case when numericalquadrature is used. The theoretical predictions are illustratedby a series of numerical experiments. For the periodic case,our results present a significant improvement on those givenby Süli & Ware (1991) SIAM J. Numer.Anal.28, 423-445).     

Paper chromatographic and paper elettrophoretic study of the solution chemistry of Tc-99m-methylendiphosphonate and of Tc-99m-dimercaptosuccinate for improving the tumour-affinity of Tc-99m during scintigraphic imaging of cancer

In order to find the conditions under which Tc-99m-methylenediphosphonate (Tc-99m-MDP) and Tc-99m(V)-dimercaptosuccinate (Tc-99m(V)-DMSA) may become tumour-seeking agents, leaving healthy organs free from the radionuclide uptake, the solution chemistry of these radiopharmaceuticals was studied by paper chromatography and paper electrophoresis in distilled water, in physiological saline, in NAHCO3, and ascorbic acid solutions. Both radiopharmaceuticals are anionic in the radiopharmaceutical solution but get easily hydrolysed to form cationic Tc-99m species which concentrates in healthy bone and in some bone metastases. Tc-99m (V)-DMSA being more stable remains long in the blood pool giving undesirable presence of the radionuclide in lung, heart and kidneys, in addition to its reduced uptake in bone metastases and in some primaries. We are trying to eliminate these drawbacks of healthy organ uptake of Tc-99-m(V)-DMSA not only to get a clean scintigraphic image of the tumour with this radiopharmaceutical but to extend its formulation, thus obtained, to prepare radiopharmaceutical with Re-188, which is the higher homologue of Tc-99m, for systemic therapy of cancer. Essentially similar solution chemistry of both radiopharmaceuticals suggests that like Tc-99m-MDP, technetium-99m-dimercaptosuccinate is also a complex of tetravalent Tc-99m and not of pentavalent Tc-99m as so far supposed to be.     

Feasibility of oak leaves as monitor for airborne pollution

The present paper confirms that evergreen oak leaves (Ouercus ilex) are a reliable biological monitor for pollution originating from vehicular traffic. By treating of experimental data statistically a simple model was obtained which explains pollution levels in terms of vehicular density and particulate resuspension effects. An extensive list of current literature in this field is also included.