Minimization of the wood wastes for an industry of furnishing: a two dimensional cutting stock problem

This paper presents the modeling and the resolution of a two dimensional cutting stock problem for a wooden industry. It is about a real problem of minimization of the wood wastes for an industry of furnishing. The raw material to be cut is a set of beams of various sizes. The purpose of the cut is to supply a list of orders characterized by a set of articles of various sizes. The problem is converted into an integer linear program where the decision variables are the numbers of beams to cut according to a set of feasible “patterns”. The designed solution is a heuristic in two stages: – Generation of the feasible patterns by various classic heuristics of the Bin-packing Problem. – Resolution of the integer linear program with the generated patterns as input variables. Moreover, based on this approach, the “Application Cutting Optimization” is developed to allow the immediate resolution of the problem and widening the stock management horizon. To end, a real case is studied to confirm the effectiveness of this approach

Structural, optical, and magnetic properties of polycrystalline Co-doped TiO2 synthesized by solid-state method

We have used a solid-state method to synthesize polycrystalline Co-doped TiO2 diluted magnetic semiconductors (DMSs) with Co concentrations of 0, and 0.5 at.%. X-ray diffraction patterns reveal that Co doped TiO2 crystallizes in the rutile tetragonal structure with no additional peaks. Transmission electron microscopy (TEM) did not indicate the presence of magnetic parasitic phases and confirmed that Co ions are uniformly distributed inside the samples. Optical absorbance measurements showed an energy band gap which decreases after doping with the Co atoms into the TiO2 matrix. Magnetization measurements revealed a paramagnetic behavior for the as-prepared Co-doped TiO2 and a ferromagnetic behavior for the same samples after annealed under a mixture of H-2/N-2 atmosphere

High-temperature ferromagnetism in Co-doped CeO2 synthesized by the coprecipitation technique

The aim of the present study is to check the influence of annealing under vacuum and a mixture of N-2-H-2 atmosphere on the magnetic properties of polycrystalline Co-doped CeO2 diluted magnetic oxides (DMOs) with Co concentrations of 5 at% synthesized using the coprecipitation technique. X-Ray diffraction (XRD) patterns and transmission electron microscopy (TEM) showed for all samples the expected CeO2 cubic fluorite-type structure and that Co ions are uniformly distributed inside the samples. Room-temperature Raman and photoluminescence (PL) spectroscopies indicate an increase in the concentration of oxygen vacancies upon Co doping and further annealing. Field dependent magnetization measurements revealed a paramagnetic behavior for as-prepared Co-doped CeO2, while a ferromagnetic behavior appears when the same samples are annealed under vacuum or N-2-H-2 atmosphere. Temperature dependent magnetization measurements suggest that the observed ferromagnetism is due to the presence of metallic Co clusters with nanometric size and broad size distribution. These results are supported by electron paramagnetic resonance studies