Installation d’essais pour la modélisation à échelle réduite des impulsions électromagnétiques

This paper presents a test platform for the scale modeling of electromagnetic pulse effects. The different elements of the installation, i.e. a vertical conical antenna placed on a metallic reference plane, a fast rise time supply generator and a data acquisition and processing facility are described. The field of the antenna has also been studied using a Numerical Electromagnetic Code (Nec)based on the moments method and a comparison with the measurements has been performed. Conclusions resulting from this first stage in the construction of the scale modeling installation are presented.     

A Neuro-fuzzy Coding for Processing Incomplete Data: Application to the Classification of Seismic Events

This letter presents a method for modelling and processing incomplete data in connectionist systems. The approach consists in applying a neuro-fuzzy coding to the input data of a neural network. After an introduction to the different kinds of imperfections, we propose a neuro-fuzzy coding in order to take incomplete data into account. We show the efficiency of this coding on the problem of the classification of seismic events. The results show that a neuro-fuzzy coding of the inputs of a neural network increases the performance and classifies incomplete data with little affect on the results.     

A combined approach to solve the redundancy optimization problem for multi-state systems under repair policies

This paper combines universal moment generating function technique with stochastic Petri nets to solve the redundancy optimization problem for multi-state systems under repair policies. Redundant elements are included in order to achieve a desirable level of production availability. The elements of the system are characterized by their cost, performance and availability. These elements are chosen from a list of products available on the market. The number of repair teams is less than the number of reparable elements, and a repair policy specifies the maintenance priorities between the system elements. A heuristic is proposed to determine the minimal cost system configuration under availability constraints. This heuristic, first applies universal moment generating function technique to evaluate the system availability, assuming unlimited maintenance resources. Once a preliminary solution is found by the optimization algorithm, stochastic Petri nets are used to model different repair policies, and to find the best system configuration (architecture and number of repairmen) in terms of global performance (availability and cost). This combined procedure is applied to a reference example.     

Novel self-assembled mesalamine–sucralfate complexes: preparation,characterization, and formulation aspects

Two well-known active agents, mesalamine (MES) and sucralfate (SUC), were investigated for possible utilization as fixed-dose combination product. The anti-inflammatory action of MES in association with bioadhesiveness and mucosal healing properties of SUC were considered promising for the development of a new compound containing both molecules, aimed as an improved treatment of ulcerative colitis. The present study investigates the capacity of the two active agents to interact and generate a new and stable entity via self-assembling. Spray-drying was used to co-process the two active principles from an aqueous mixture where the ratio MES:SUC was in the range 25:75, 50:50, and 75:25. The structural data (X-Ray, FTIR, SEM, DSC, and ¹H NMR) have shown that MES and SUC are interacting leading to complexes with properties differing from those of each separate active agent and from their physical blends. ¹H NMR results indicated that complexation occurred when the aqueous suspensions of drugs were mixed, prior to spray-drying. Drug–drug self-assembling was the driving mechanism in the formation of the new entity. Based on the structural data, a hypothetical structure of the complex was proposed. Co-processing of MES and SUC represents a simple and useful procedure to prepare new self-assembled compounds by valorizing the ionic interactions between the two entities. Preliminary studies with oral solid dosage forms based on MES–SUC complexes tested in vitro have shown a controlled MES release, opening the perspective of a new colon-targeted delivery system and a novel class of compounds with therapeutic application in inflammatory bowel diseases.     

Electroseparation of an antibacterial peptide fraction from snow crab by-products hydrolysate by electrodialysis with ultrafiltration membranes

Recently, a snow crab by-products hydrolysate has demonstrated antibacterial properties due to a peptide with a molecular weight of about 800 Da, but only at high concentration. Consequently, peptide hydrolysate has been fractionated to obtain peptides in a more purified form. The aim of this work was to separate a snow crab by-products hydrolysate by electrodialysis with ultrafiltration membranes (EDUF). EDUF, which allows separation of molecules according to their charges and molecular weights, was used to recover and concentrate the active antibacterial fraction. Two different ultrafiltration membranes (20 and 50 kDa) and two electrical field strengths (2 and 14 V/cm) were used as separation parameters. After EDUF separation, the 300-600 Da peptide molecular weight range was the most recovered with an abundance of 94%. Moreover, fractionation at 14 V/cm with ultrafiltration membranes of 50 kDa allowed the recovery of an anionic fraction which showed antibacterial properties on Escherichia coli ATCC 25922 and Listeria innocua HPB 13.     

In-Situ Analyzing the Influence of Thermoelectromagnetic Convection on the Nucleation Ahead of the Advancing Interface During Directional Solidification

Sn-3wt%Pb alloy was directionally solidified without and with a 0.08T transverse magnetic field(TMF),and real-time recorded by in-situ synchrotron X-ray imaging.Results indicate that TMF shortened the distance from the location of nucleation to the advancing interface,and accelerated the growth rate of the equiaxed crystal,which caused the columnar-to-equiaxed transition(CET)finally.The thermoelectromagnetic convection(TEMC)in front of the interface and around the crystal’s dendritic branch should respond to changes of the distance and the growth rate.     

Benchmarking flexible job-shop scheduling and control systems

Benchmarking is comparing the output of different systems for a given set of input data in order to improve the system’s performance. Faced with the lack of realistic and operational benchmarks that can be used for testing optimization methods and control systems in flexible systems, this paper proposes a benchmark system based on a real production cell. A three-step method is presented: data preparation, experimentation, and reporting. This benchmark allows the evaluation of static optimization performances using traditional operation research tools and the evaluation of control system's robustness faced with unexpected events.