A particle swarm approach for multi-objective optimization of electrical discharge machining process

This paper proposes an experimental investigation and optimization of various machining parameters for the die-sinking electrical discharge machining (EDM) process using a multi-objective particle swarm (MOPSO) algorithm. A Box–Behnken design of response surface methodology has been adopted to estimate the effect of machining parameters on the responses. The responses used in the analysis are material removal rate, electrode wear ratio, surface roughness and radial overcut. The machining parameters considered in the study are open circuit voltage, discharge current, pulse-on-time, duty factor, flushing pressure and tool material. Fifty four experimental runs are conducted using Inconel 718 super alloy as work piece material and the influence of parameters on each response is analysed. It is observed that tool material, discharge current and pulse-on-time have significant effect on machinability characteristics of Inconel 718. Finally, a novel MOPSO algorithm has been proposed for simultaneous optimization of multiple responses. Mutation operator, predominantly used in genetic algorithm, has been introduced in the MOPSO algorithm to avoid premature convergence. The Pareto-optimal solutions obtained through MOPSO have been ranked by the composite scores obtained through maximum deviation theory to avoid subjectiveness and impreciseness in the decision making. The analysis offers useful information for controlling the machining parameters to improve the accuracy of the EDMed components.     

A new region aware invisible robust blind watermarking approach

Multimedia Tools and Applications - The multimedia revolution has made a strong impact on our society. The explosive growth of Internet access to this digital information has generated new...     

A Cross-Layer (Layer 2 + 3) Handoff Management Protocol for Next-Generation Wireless Systems

Next-generation wireless systems (NGWS) integrate different wireless networks, each of which is optimized for some specific services and coverage area to provide ubiquitous communications to the mobile users. It is an important and challenging issue to support seamless handoff management in this integrated architecture. The existing handoff management protocols are not sufficient to guarantee handoff support that is transparent to the applications in NGWS. In this work, a cross-layer (Layer 2 + 3) handoff management protocol, CHMP, is developed to support seamless intra and intersystem handoff management in NGWS. Cross-layer handoff management protocol uses mobile's speed and handoff signaling delay information to enhance the handoff performance of Mobile IP that is proposed to support mobility management in wireless IP networks. First, the handoff performance of Mobile IP is analyzed with respect to its sensitivity to the link layer (Layer 2) and network layer (Layer 3) parameters. Then, a cross-layer handoff management architecture is developed using the insights learnt from the analysis. Based on this architecture, the detailed design of CHMP is carried out. Finally, extensive simulation experiments are carried out to evaluate the performance of CHMP. The theoretical analysis and simulation results show that CHMP significantly enhances the performance of both intra and intersystem handoffs.     

Effect of thiourea during nickel electrodeposition from acidic sulfate solutions

The effect of thiourea on the cathodic current efficiency (CE), deposit quality, crystallographic orientations, surface morphology, and polarization behavior of the cathode was investigated during nickel electrodeposition from acidic sulfate solutions for 2 hours at 60 °C. A slight decrease of 3 to 4 pct in the CE was observed, when the concentration of thiourea was increased from 2 to 40 mg dm⁻³. The nickel deposit quality deteriorated significantly at higher thiourea concentrations; the surface morphology deteriorated and the contamination of the nickel deposits increased. The presence of thiourea affected the peak intensities of the crystal planes. Cyclic voltammetric studies on nickel deposition at 25 °C revealed depolarization behavior of the cathode at lower thiourea concentrations, ≤10 mg dm⁻³; however, a mixed behavior is observed at higher thiourea concentrations. These changes were also observed in the exchange current density (i ₀) values.     

Samarium Ion-Doped Maghemite Nanoparticles: Synthesis,Microstructural, Optical,and Magnetic Characterizations

Journal of Superconductivity and Novel Magnetism - This paper reports the effects of rare-earth Sm3+ ion substitution on structural, optical, electronic, and magnetic responses of maghemite...     

Optimization of tensile properties thermoplastic blends from soy and biodegradable polyesters: Taguchi design of experiments approach

Soy meal-based biodegradable blends were prepared by melt extrusion process. The effects of denaturants, i.e., urea and sodium sulfite and plasticizer (glycerol) and polyester type (polybutylene succinate, polycaprolactone, polybutylene adipate terephthalate) on tensile strength and elongation at break were investigated using a Taguchi experimental design approach. The results showed that the sodium sulfite had little or no effect on final properties of the blends. Also, biodegradable polyester type had significant effect on the tensile strength and elongation at break of the blends prepared. The predicted values and experimental were found to be in tune with each other. The chemical structure and morphology of the optimum sample was probed by FT-IR spectroscopy and scanning electron microscopy (SEM). Also, the results provided an insight into how important the plasticization and destructurization of soy protein to obtain the blends with desired mechanical properties.     

C5: A Step Towards Smart World with Enhanced Holistic Wellbeing

Wireless Personal Communications - Internet of things (IoTs) has been the smartest technology proven worldwide these days. The application products of IoTs are Mobile ad hoc network (MANET) and...