DSS approach for heterogeneous parallel machines scheduling considering proximate supply chain constraints

This paper describes the basis of a Decision Support System (DSS) designed to schedule fertiliser production orders to be delivered within time windows, in plants made up of multiple heterogeneous parallel processors (production lines), considering that fertiliser production rates and nomenclatures depend on lines, that setup times depend on sequence and lines, and taking into account downtime constraints (preventive maintenance?…). A mixed linear programming model is encapsulated in the DSS which considers the schedule’s impacts, immediately upstream and downstream of plants in the supply chain. These side-effects may make the proposed solution unfeasible and the DSS helps redefining the problem to avoid them.     

Comparative study of the extraction methods for recovery of carotenoids from algae: extraction kinetics and effect of different extraction parameters

Carotenoid extraction from algae is currently under intensive research due to the increased demand for naturally occurring compounds, which are especially rich in biologically active isomers. Furthermore, natural carotenoids exhibit greater stability than synthetic ones. Conventional liquid extraction suffers from several drawbacks, such as use of high amounts of solvent, and several extraction steps. In this work carotenoid extraction from algae using different methods, such as microwave and ultrasound assisted extraction as well as pressurized liquid extraction and extraction with supercritical CO₂ and ethane, is summarized together with modelling of extraction kinetics. In addition carotenoid availability, algae pretreatment, stability of extracts, their antioxidative and antimicrobial activities as well as downstream processing and storage of algae extracts have been reviewed. As a conclusion it can be stated that carotenoid extraction is complex, demanding optimization of the carotenoid yield and antioxidative stability, which are often inversely proportional. © 2014 Society of Chemical Industry     

Parallelization Strategy for Elementary Morphological Operators on Graphs: Distance-Based Algorithms and Implementation on Multicore Shared-Memory Architecture

This article focuses on the (unweighted) graph-based mathematical morphology operators presented in Cousty et al. (CVIU 117(4):370–385, 2013). These operators depend on a size parameter that specifies the number of iterations of elementary dilations/erosions. Thus, the associated running times increase with the size parameter, the algorithms running in \(O(\lambda .n)\) time, where n is the size of the underlying graph and \(\lambda \) is the size parameter. In this article, we present distance maps that allow us to recover (by thresholding) all considered dilations and erosions. The algorithms based on distance maps allow the operators to be computed with a single linear O(n) time iteration, without any dependence to the size parameter. Then, we investigate a parallelization strategy to compute these distance maps. The idea is to build iteratively the successive level-sets of the distance maps, each level-set being traversed in parallel. Under some reasonable assumptions about the graph and sets to be dilated, our parallel algorithm runs in \(O(n/p + K \log _2 p)\) where n, p, and K are the size of the graph, the number of available processors, and the number of distinct level-sets of the distance map, respectively. Then, implementations of the proposed algorithm on a shared-memory multicore architecture are described and assessed on datasets of 45 images and 6 textured three-dimensional meshes, showing a reduction of the processing time by a factor up to 55 over the previously available implementations on a 8-core architecture.     

Development of new sustainable inorganic flame retardant additive system for polyamide 6,6 with improved performance

We report the effect of new sustainable inorganic phosphate glass (P‐glass) flame retardants for polyamide 6,6 (PA6,6). Three P‐glasses differing in chemical composition and glass transition temperature (T_g) were prepared and their flame retardant effect on PA6,6 was studied by cone calorimetry, thermogravimetric analysis, and SEM‐EDX. The effect of high and intermediate T_g P‐glasses on the thermal stability of PA6,6 was negligible as compared to that of the low T_g P‐glass due to the hygroscopic nature of the latter. However, the char formation was independent of the P‐glass composition and was observed to increase by 30% in the presence of P‐glass. The low T_g P‐glass composition (i.e., ILT‐1) was found to be a promising flame retardant for PA6,6 at a concentration of up to 15% by weight. Cone calorimetry data showed that the ILT‐1 decreased both the peak heat release rate and the total heat amount released from the PA6,6/ILT‐1 hybrids, resulting in an efficient formation of a glassy char layer. In contrast to the intermediate and high T_g P‐glasses of this study, SEM‐EDX indicated that the ILT‐1 P‐glass was well dispersed in the PA6,6 matrix to yield a typical droplet‐in‐matrix phase morphology in the melt‐blended binary immiscible P‐glass/PA6,6 hybrids. POLYM. ENG. SCI., 55:1741–1748, 2015. © 2014 Society of Plastics Engineers     

Etude de l'élimination des ions Cu (II) de la solution aqueuse par sorption sur la zéolithe a study of the removal of Cu (II) from aqueous solution by sorption on Zeolite A

The objective of this study is to present the results of removal of copper by the method of sorption on zeolite A. The batch experiments were conducted for both the kinetics for the sorption isotherms. The experimental variables studied were pH, contact time at different initial concentrations, the amount of sorbent, temperature and stirring speed. The sorption capacity depends on the pH and mass of sorbent, but the temperature and stirring rate showed no influence. Several mechanisms of retention of copper on the zeolite could be competitive (ion exchange, complexation or precipitation and sorption). The modeling of experimental data on kinetics showed that the model of pseudo‐second order describes satisfactorily the sorption on the zeolite, and that the limiting step of the speed distribution intraparticle. Statistical analysis of the constants for Langmuir‐Freundlich equation has shown that this model seems most appropriate to describe this phenomenon of sorption, which indicates the heterogeneity of the surface sorption of the zeolite. Copyright © 2011 Canadian Society for Chemical Engineering     

A new hybrid quantitative structure property relationships-support vector regression (QSPR-SVR) approach for predicting the solubility of drug compounds in supercritical carbon dioxide

The purpose of this work was to compare the performance of 7 meta-heuristics algorithms namely: Dragonfly (DA), Ant Lion (ALO), Grey Wolf (GWO), Artificial Bee Colony (ABC), Particle Swarm (PSO), Whale (WAO), and a hybrid Particle Swarm with Grey Wolf (HPSOGWO) optimizers in terms of fine-tuning hyper-parameters of a hybrid quantitative structure property relationships (QSPR)-support vector regression (SVR) for the prediction of molar fraction solubilities of drug compounds in supercritical carbon dioxide (SC-CO₂). A dataset of 168 drug compounds, 13 inputs, and 4490 experimental data points was used to achieve the goal. All 7 models were statistically and graphically approved while the HPSOGWO-SVR was found to over-perform with an average absolute relative deviation (AARD) of 0.706% and an AIC of −14,434,249. The model was subjected to an external test (validation) using 160 experimental data points that were not used in the training and the test set. The overall results proved that the obtained model has good predictivity ability and robustness.     

Fatigue performance investigation on the automotive welded structure under damped loads using the Taguchi method

In the present paper, a three-dimensional numerical model has been built using ANSYS code to analyze the static and fatigue behavior of a welded design based on four rectangular profiles under damped loads for automotive application. The fatigue of the proposed design is generally influenced by a number of factors. The aim of this study is to investigate the effect of the load level, the stress ratio, the mean stress theory, the geometry size, the weld bead height, the temperature of the weld bead on the durability (P₁), and the maximum of von Mises stress (P₂) at the critical areas in the welded structure. As well as the length and the stiffness of the spring have been furtherly investigated. For this purpose, the application of the Taguchi method with computational simulation was performed for the target to determine the optimum operating parameters conditions. The results indicated that the optimum levels yielding a higher performance for P₁ and P₂ were (L1, L2, L2, L3, L1, L1, L3, and L3) and (L2, L3, L3, L3, L3, L3, L3, and L2), respectively. Thus, it revealed that the weld temperature was the predominant parameter influencing P₁ and the mean stress theory factor was the most significant parameter influencing P₂. This study led to defining a regression equation relating the output parameters with the selected factors. Consequently, the percentage error between regression equation calculations and computational outputs of fatigue life and maximum von Mises stress corresponding to the most optimal combinations obtained from Taguchi calculations was 0.92% and 0.63%, respectively. In fact, several parameters have been employed in this durability assessment to characterize the behavior of welded rectangular profiles prototype to predict the overall behavior of the suspension system of the automotive.     

Synthesis,Characterization and Adsorption of Bisphenol A Using Novel Hybrid Materiel Produced from PANI Matrix Reinforced by Kieselguhr

Journal of Inorganic and Organometallic Polymers and Materials - This study investigated the preparation of new adsorbent based PANI and Kieselguhr (KG). The produced materials were characterized...