Minimising total weighted earliness and tardiness on parallel machines using a hybrid heuristic

Scheduling jobs with different processing times and distinct known due dates on parallel machines (which may be idle) so as to minimise the total weighted earliness and tardiness is NP-hard. It occurs frequently in industrial settings with a just-in-time production environment. Here, small instances of this problem are tackled via an exact mixed-integer program, whereas larger instances are approximately solved using hybrid algorithms. The computational investigation discerns what makes a difficult instance, and demonstrates the efficiency of the approach.     

Automatic layout of statecharts

Graphical notations are widely used for system specification. The usefulness of these notations depends primarily on their readability. Hence, automatic methods are needed to obtain efficient and understandable graphical representations of requirements. In this paper, we present an algorithm that automatically generates layouts of statecharts. We assume that relevant information is stored in a structure that we call a decomposition tree, and we draw the graph that models a statechart in a hierarchical fashion. Our approach excludes diagrams with inter‐level transitions. Copyright © 2001 John Wiley & Sons, Ltd.     

Effect of E-Glass fibre and ply orientation on the mechanical behaviour of FRP composites used for pressure pipe

The main goals of this experimental investigation were to compare the mechanical behaviour of resins reinforced with different woven fabrics (bidirectional and quadriaxial rovings), manufactured with the classical hand lay-up process, and to find the more appropriate industrial pressure pipe. In order to realize such applications, several mechanical properties need to be evaluated. So, a focus was essentially done on the evaluation of the effect of resin and E-Glass fibre ply orientation on the mechanical properties such as tensile strength and flexural strength of the studied composite laminates. An experimental failure analysis was carried out to observe the crack paths and failure mechanisms in the investigated laminate composites. From the main results, it was found that the composites based on R500 fabrics show the best behaviour in tensile while the laminates based on RM fabrics present the best flexural properties. The quadriaxial composite laminates (QA/VE and QA/UP) with stacking sequences of [0°, +45°, 90°, ?45°] present a very ductile tensile behaviour and the highest interlaminar fracture resistance. Consequently, they can be more appropriate for the industrial pressure pipe.     

Effect of elaboration parameters of a membrane ceramic on the filtration process efficacy

The formation of the flat membrane from kaolin and potassium phosphate was investigated with a particular focus on the appropriate elaboration parameters and the effect of their separation performance. The first step consisted in the fabrication of flat ceramic membrane supports from mechanochemicaly-treated kaolin (K) and starch (S). The mechanical properties, permeability and porosity of these supports were studied as a function of the milling time of kaolin, the starch content, the sintering temperature and time. The optimization of the elaboration parameters led to the fabrication of supports from kaolin milled for 30 min and 5% starch at sintering temperature of 1100 °C and sintering time of 1 h. In the second step, the potassium phosphate was added as a binder in the kaolin- 5% starch mixture. In this case, we noted the improvement of the permeability without reduction of the mechanical strength and porosity. Also, the separation performances and the fouling of membranes elaborated with different potassium phosphates were evaluated using Bovine Serum Albumin (BSA) solution.     

Ant colony systems for the single-machine total weighted earliness tardiness scheduling problem

Single-machine weighted earliness tardiness scheduling is a prevalent problem in just-in-time production environments. Yet, the case with distinct due dates is strongly NP-hard. Herein, it is approximately solved using ASV, an ant colony-based system with a reduced number of ants and of colonies and with daemon actions that explore the search space around the ants using a variable neighborhood search (VNS). The numerical investigation provides computational proof of the utility of the daemon actions. In addition, it infers that these latter can be applied either to the initial or to subsequent colonies. Furthermore, it highlights the importance of using ant colony optimization as the multiple restart engine of VNS. Finally, it shows that ASV obtains the optimum for most small-sized instances. It has a 0.2 % average deviation from the optimum over all benchmark instances.     

Differential Impact of Sex on Seasonal Changes in Mantle and Tentacle Phospholipids and Triacylglycerols in Sepia officinalis

The aim of the present work was to study the effect of season on phospholipids and triacylglycerols (TAG) of mantle and tentacles of female and male wild Sepia officinalis. The identified phospholipids were phosphatidylethanolamine (PtdEtn), phosphatidylcholine (PtdCho), phosphatidylserine (PtdSer), and phosphatidylinositol (PtdIns), and PtdEtn was the major fraction. Results showed apparent seasonal variation of phospholipid content, particularly with female samples. Fatty acid composition of phospholipid classes showed a differentiation much more in the proportions than in the diversity of fatty acids. Results showed that the major saturated fatty acids were 16:0 and 18:0, the major monounsaturated fatty acids were 18:1 and 20:l, and the major polyunsaturated fatty acids were docosahexaenoic acid (22:6n-3) (DHA) and eicosapentaenoic acid (20:5n-3) (EPA). The results relative to TAG demonstrated significant variations. Principal component analysis confirmed the seasonal and sexual effects. This study could be appropriate for the improvement of consistent monitoring of phospholipid and TAG accumulation in cephalopod, which might be important for both physiological studies and food industries.     

Dyeing properties of cationized and non-cationized cotton fabrics dyed with Vitis vinifera L. leaves extract

This study lays bare two main objectives. The first is to determine the amount of anthocyanins in the leaves of Vitis vinifera L. by the spectrophotometric method and the second is to dye cationized and non-cationized cotton fabrics with the V. vinifera L. leaves aqueous extract. We have thoroughly investigated the effects of dye bath pH and temperature on the dyeing proprieties of the aforementioned fabrics. The color strength (K/S value) of dyed cationized cotton fabrics (K/S = 12) has been better than the non-cationized ones (K/S = 4). Experimental results show that the fastness properties of dyed cationized cotton fabrics range from average to good. We find that the cationization of cotton fabrics has largely improved the dyeability and fastness properties of cotton fabrics dyed with V. vinifera L. leaves aqueous extract.     

Faceting mechanisms of Si nanowires and gold spreading

We report detailed structural analysis of 〈111〉 oriented silicon nanowires (NWs) grown by UHV–CVD using the VLS process with a gold catalyst. STEM-HAADF observations have revealed an unexpected inhomogeneous distribution of gold nanoclusters on the NW surface. Gold is mainly distributed on three sides among the six {112}-sidewalls and is anchored on upward {111} facets. This original observation brought us a new comprehension of the faceting mechanisms. The stability of the 〈111〉 growth direction needs the formation of facets on {112}-sidewalls with energetically favorable planes. We demonstrate that the initial formation of covered facets with a three-fold symmetry is driven by the formation of {111} Au/Si interfaces between the nucleated Si NW and the Au droplet.     

Polybenzidine-montmorillonite nanocomposites: synthesis via a mechanochemical intercalation method

A new and clean preparation method of Polybenzidine-montmorillonite conducting nanocom-posites is reported in this paper. Solid-solid reaction was successfully used to synthesize these hybrid materials by grinding mixtures of various amounts of benzidine (BZ) and sodium montmorillonite. The characterization techniques confirmed the incorporation of BZ in the nanospace of the clay and showed that BZ molecules intercalate with a monolayer arrangement parallel to the plan of the clay layers. The amount of BZ and the presence of the clay affect deeply the melting point of benzidine and favour the formation of new crystal-lographic phases. Polymerization of benzidine between the clay layers was performed using the same method by adding ammonium peroxodisulfate. The formation of four types of polymers in the interlayer space of the clay was pointed out. One of them is probably responsible for the enhancement of the conductivity when compared to the clay-free polybenzidine sample.