Genetic algorithms to solve the cover printing problem

Inspired by successful application of evolutionary algorithms to solving difficult optimization problems, we explore in this paper, the applicability of genetic algorithms (GAs) to the cover printing problem, which consists in the grouping of book covers on offset plates in order to minimize the total production cost. We combine GAs with a linear programming solver and we propose some innovative features such as the “unfixed two-point crossover operator” and the “binary stochastic sampling with replacement” for selection. Two approaches are proposed: an adapted genetic algorithm and a multiobjective genetic algorithm using the Pareto fitness genetic algorithm. The resulting solutions are compared. Some computational experiments have also been done to analyze the effects of different genetic operators on both algorithms.     

Properties and microstructural aspects of TiO2‐doped sintered Alumina‐Zirconia composite ceramics

The effect of titania content on the densification, the phase transformation, the microstructures, and mechanical properties of 50 wt% Al₂O₃‐50 wt% ZrO₂ (12 mol% CeO₂) was evaluated. Ceramic composites with different TiO₂ content (0.27, 5, 10 wt%) were prepared by pressureless sintering at low temperature (1400°C) for 2 hours in air. Dense ceramic was obtained by adding 5 wt% of TiO₂ loading to improved mechanical properties. The microstructure analysis provided lots of information about solid‐state reactivity in alumina‐zirconia‐titania ternary system. The content of TiO₂ strongly affected the phases evolution and the grain growth during sintering. Furthermore, a significant effect on mechanical properties and fracture behavior was also observed.     

Damage in dual phase steels and its constituents studied by X-ray tomography

Damage in a dual phase steel was measured using in situ high-resolution X-ray absorption tomography. A comparison with the behavior of its two constituents ferrite and martensite, taken separately, was also achieved in the present work. The method was particularly useful for analyzing the respective contribution of nucleation and growth of voids in the studied materials. Quantitative analysis of the damage events was carried out on a same 3D region inside the reconstructed volumes at different deformation steps for different samples cut from the three kinds of materials. Void number prediction and growth model, based on local stress triaxiality, show a good agreement with the experimental data.     

Date syrup: Effect of hydrolytic enzymes (pectinase/cellulase) on physico-chemical characteristics, sensory and functional properties

This work is a contribution to give value addition to second grade dates (with hard texture) by the production of enzymatically treated syrup with high commercial value. It was observed that the pulp:water at ratio 1:3 treated with 50 U of pectinase and 5 U of cellulase during 120 min at 50 °C gave the highest recovery of total soluble solids (72.37 g of total soluble solids/100 g fresh basis) and the lower turbidity (186.45 NTU) compared with control without enzyme addition (Total soluble solids yields: 66.34 g of total soluble solids/100 g fresh basis and turbidity: 1513 NTU). physico-chemical measurements indicated that carbohydrates were predominant in all date varieties as well as their syrups (∼69.59-83.76 g/100 g dry matter in dates and ∼62.14-74.68 g/100 g fresh weight in syrup). Allig variety was characterised by a high content of reducing sugars content (∼77.91 g/100 g dry matter), contrary to Deglet Nour (∼23.17 g/100 g dry matter) and Kentichi (∼21.3 g/100 g dry matter).The CIE L∗ a∗ b∗ colour values of the enzyme-treated date syrup of Deglet Nour, Allig and Kentichi variety showed lighter colours (L∗ values ranging from 24.16 to 44) than the control without enzyme (L∗ values ranging from 0.545 to 17.2). Hedonic evaluation showed that enzyme-treated date syrup was more appreciated by consumers. Microbiological study showed that date syrups were free from aerobes, moulds, coliforms and enterobacteriaceae and were microbiologically stable during five months storage. Results suggested that enzymatic treatment could be used for production of date syrup with high commercial value     

Stability of refined olive oil and olive‐pomace oil added by phenolic compounds from olive leaves

Refined olive oil and olive‐pomace oil were enriched with olive leaf phenolic compounds in order to enhance its quality and bring it closer to virgin olive oil. The changes that occurred in the concentrations of pure oleuropein, oleuropein aglycone, hydroxytyrosol acetyl and α‐tocopherol at 400 µg/kg of oil during the storage of refined olive oil and olive‐pomace oil under accelerated conditions (50 °C) were investigated. In a period of 4 months, α‐tocopherol decomposed by 75% whereas less than 40% of the phenols were lost. During storage, enzymatic olive leaf extract hydrolysate that contains two major compounds, hydroxytyrosol and oleuropein aglycone showed the highest antioxidant activity and the lowest detected stability, followed by oleuropein. The oleuropein in olive leaf extracts exhibited similar degradation profiles, reducing by 60–50% and 80% for the olive oil and olive‐pomace oil in 6 months, respectively. The acetylated extract, however, displayed a loss of 10 and 5% in olive oil and olive‐pomace oil, respectively. In the fatty acid composition, an increase in oleic acid and a decrease in linoleic acid were observed. The antiradical activities of the olive oil and olive‐pomace oil enriched with olive leaf phenolic compounds at 400 ppm showed that enzymatic hydrolysate extract had the highest protective effect against oil oxidation. Based on the Rancimat method, the oils with added leaf enzymatic hydrolysate extract had the lowest peroxide value and the highest stability. After 6 months of storage and at 120 °C, the oxidative resistance of refined olive oil and olive‐pomace oil reached 0.71 and 0.89 h, respectively, whereas that of the non‐enriched samples fell to zero.     

Design and characterization of a lamellar nanostructure in a low C steel

A fully lamellar ferrite/cementite nanostructure was designed in a low C steel by using a specific thermal treatment. The strengthening of such microstructure has been investigated as a function of prestrain by rolling up to a deformation of 300%. As in usual pearlitic structure, its work-hardening shows no saturation and its elongation to fracture remains rather constant instead of decreasing drastically as conventional steels. The hardening by a similitude effect is thus not the privilege of pearlitic steels. Nevertheless, its lower initial work-hardening rate at low strain compared to an equivalent pearlitic steel and a lower hardening potential at high strain let us suspect major differences in the nature and the behaviour of ferrite channels in relation to the morphogenesis of the microstructure. This study opens a new way to obtain low carbon ultra-high strength steel by a nanostructuration process using severe plastic deformations.     

Architecturing of Metal‐Based Composites with Concurrent Nanostructuring: A New Paradigm of Materials Design

Over the past decades severe plastic deformation (SPD) techniques advanced to one of the most potent ways of producing bulk ultrafine grained materials. The main advantage of SPD is the ultra‐high strength they can deliver. While the improvement of the strength there is a limit to what is achievable SPD when they are applied to individual materials especially for strain‐hardening and ductility. Therefore a new application of SPD processes in manufacturing of architecture hybrid materials with simultaneous nanostructuring is investigated experimentally and theoretically.