Identifying and Modeling the Strengths and Weaknesses of Major Economic Models in Grid Resource Management

Economic-based approaches have been found to be effective for distributed resource management in Grid computing. However, deciding which model to use is challenging, because (1) the performance stability of a particular model in a dynamic and distributed environment, is hard to establish (2) the performance objective of the Grid network may be complex, and it is difficult to know which model would best fit such an objective, (3) evidence indicates that no single model can cope with every scenario, and (4) no suitable tools exist to accurately predict and contrast the performances of one model with another model in a particular domain. Understanding the strengths and weaknesses of widely proposed economic models in terms of a range of scenarios is, therefore, crucial. To address this, the authors developed a general evaluation platform suitable for analyzing the performance of different economic models in the Grid. This work identifies domains of strength of individual models and highlights their use in various scenarios of Grid computing.     

Evaluation of corrosion behavior of surface modified Ti–6Al–4V ELI alloy in hanks solution

The passive film behavior of Ti–6Al–4V ELI (Extra Low Interstitial) alloy after a chemical treatment followed by a thermal treatment was morphologically and electrochemically characterized. The surface morphological studies were carried out using scanning electron microscopy (SEM), electron dispersive X-ray analysis (EDAX), and Fourier Transformed-Infra Red (FT-IR) analysis to investigate the nucleation and growth of apatite on the chemically and thermally treated Ti–6Al–4V ELI alloy immersed for different durations in Hanks solution. Polarization and impedance spectroscopic (EIS) measurements were carried out in Hanks solution and the electrical parameters were obtained for the passive film using a non-linear least square fitting (NLLS) method.     

Ambient RF energy harvesting system: a review on integrated circuit design

This paper presents a comprehensive review of ambient RF energy harvester circuitry working on integrated circuits. The review covers 3 main blocks in an RF energy harvesting system implemented on chip. The blocks are the rectifier, impedance matching circuit and power management unit. The review of each block includes its operational principle, reported state-of-the-art circuit enhancement techniques, and design trade-offs. We compare the circuits in each block with respect to the techniques adopted to improve the performances for RF energy harvesting. To identify the benefits and limitations associated with the architecture we discuss the advantages and disadvantages of the circuit topologies in each block of an ambient RF energy harvester.     

Studies on the effect of anions of various lithium salts in PEMA gel polymer electrolytes

This research synthesized graft copolymers of chitosan‐g‐poly(N‐isopropyl acrylamide) (CS‐g‐PNIPAAm) by UV‐initiated free‐radical polymerization of NIPAAm monomer to CS selectively at the C‐6 position of pyranose ring. First, amino groups in CS were protected by reaction with phthalic anhydride (PA) to form PACS. The degree of phthaloylation was carefully controlled to ensure that most amino groups were protected, and only a very small amount of hydroxyl groups were reacted. In the second step, the vinyl functional group was introduced to the PACS by reaction with a vinyl compound containing an isocyanate group (3‐isopropenyl‐αα′‐dimethylbenzyl isocyanate), through the urethane linkage with hydroxyl groups at the C‐6 position. The phthaloyl groups were then removed by hydrazine to recover the amino groups in CS. Finally, PNIPAAm was grafted to the vinyl CS at the C‐6 position by UV‐initiated free‐radical polymerization. The synthesized CS‐g‐PNIPAAm copolymers were confirmed to have a structure of an AB‐crosslinked graft copolymer. Respectively, these copolymer hydrogels exhibited pH‐ and thermal‐responsive swelling properties in an aqueous solution due to their CS and PNIPAAm components. The test of cell viability with L929 fibroblast revealed that the CS‐g‐PNIPAAm copolymers having a grafting ratio lower than 1.7 had cellular compatibility as good as pure CS. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

A process for the production of sub-micron to millimetre sized thermally stable α-alumina spheres

The sol-emulsion-gel method has been employed to produce alumina gel spheres from unseeded as well as seeded alumina sol. Controlled heating of the unseeded gel spheres leads to the formation of α-alumina phase at 1200°C. Various seeds have been tried to determine the effect of seeding on the formation of α-alumina and it is found that seeding with 0.5 wt.% Fe₂O₃ leads to the formation of α-alumina at a relatively low temperature of 950°C. The sizes of the microspheres can be varied in the range between 0.5 μm and 1 mm by suitable choice of the process parameters. The resultant gel spheres on controlled heating transform into thermally stable α-alumina spheres.     

Dielectric and thermal response of poly[(vinylidene chloride)‐co‐acrylonitrile]/poly(methyl methacrylate) blend membranes

Poly(methyl methacrylate) was mixed with poly[(vinylidene chloride)‐co‐acrylonitrile] (Saran‐F) and lithium perchlorate in tetrahydrofuran to make polymer blend systems. Solvent‐free membranes with various blend ratios were prepared using a solution casting technique. Impedance analysis was used to study the electrical response of the polymer membranes, which shows that the 50:50 wt% blend ratio polymer membrane has a low bulk resistance and high dielectric constant at room temperature and hence high ionic conductivity. The dielectric behaviour was analysed using dielectric permittivity and electric modulus of the samples. The conductance spectra follow the universal power law variation. Structural analysis confirms the amorphous nature and functional group analysis confirms the miscibility. The decomposition temperature of the membranes was determined using thermogravimetric analysis. © 2014 Society of Chemical Industry