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).     

Chemoselective synthesis of oligosaccharides of 2-deoxy-2-aminosugars

Along with the application of the S-benzoxazolyl glycosides to the high-yielding synthesis of disaccharides of the 2-amino-2-deoxy series, chemoselective assembly of oligosaccharides containing multiple residues of 2-amino-2-deoxyglycoses is reported. This modified armed-disarmed approach is relying on the observation that 2-N-trichloroethoxycarbonyl derivatives of S-benzoxazolyl glycosides are significantly more reactive than their 2-N-phthaloyl counterparts in MeOTf-promoted glycosylations. This allowed efficient chemoselective synthesis of 1,2-trans-linked oligosaccharides, the disarmed reducing end of which can be activated for immediate second step glycosidation in the presence of a more powerful activator, AgOTf. As a result of this two-step activation, trans-trans-patterned trisaccharides could be assembled in a highly efficient manner. This result differs from the classic armed-disarmed technique, according to which usually cis-trans-patterned oligosaccharides are generated.     

Subpicosecond electro-optic measurement of relativistic electron pulses

Time-resolved measurements of the transverse electric field associated with relativistic electron bunches are presented. Using an ultrafast electro-optic sensor close to the electron beam, the longitudinal profile of the electric field was measured with subpicosecond time resolution and without time-reversal ambiguity. Results are shown for two cases: inside the vacuum beam line in the presence of wake fields, and in air behind a beryllium window, effectively probing the near-field transition radiation. Especially in the latter case, reconstruction of the longitudinal electron bunch shape is straightforward.