Studying the Effect of Cobalt Doping on Optical and Magnetic Properties of Zinc Oxide Nanoparticles

Silicon - Nano-crystalline powders of Zn1−xCoxO with $\left (0.0\le x\le 0.07 \right )$ have been synthesized by sol-gel method. X-ray diffraction patterns of the prepared samples confirm the...     

Reconfigurable Control Structure for Robots in Assembly

The increased use of changeable characteristics in modern manufacturing and robotic systems and applications call for improved system control design that offers some degree of reconfigurability. The need for control reconfiguration of robotic systems arises due to some inherent characteristics of the robotic system, variations of robot parameters due to environmental changes, major task changes typical in production changeover or manufacturing system reconfiguration, or geometry changes due to the reconfiguration of modular manipulators. In this paper, a reconfigurable controller, the Supervisory Control Switching System (SCSS), is proposed to meet the new on-line demands for changeability in robotic systems. The SCSS is capable of selecting the most suitable controller for a particular task or situation, from separate controllers designed a priori. The applicability and effectiveness of the developed switching control scheme have been illustrated through computer simulations of an AdeptOne SCARA manipulators carrying out assembly tasks.     

Mathematical modelling and a meta-heuristic for flexible job shop scheduling

This study develops new solution methodologies for the flexible job shop scheduling problem (F-JSSP). As a first step towards dealing with this complex problem, mathematical modellings have been used; two novel effective position- and sequence-based mixed integer linear programming (MILP) models have been developed to fully characterise operations of the shop floor. The developed MILP models are capable of solving both partially and totally F-JSSPs. Size complexities, solution effectiveness and computational efficiencies of the developed MILPs are numerically explored and comprehensively compared vis-à-vis the makespan optimisation criterion. The acquired results demonstrate that the proposed MILPs, by virtue of its structural efficiencies, outperform the state-of-the-art MILPs in literature. The F-JSSP is strongly NP-hard; hence, it renders even the developed enhanced MILPs inefficient in generating schedules with the desired quality for industrial scale problems. Thus, a meta-heuristic that is a hybrid of Artificial Immune and Simulated Annealing (AISA) Algorithms has been proposed and developed for larger instances of the F-JSSP. Optimality gap is measured through comparison of AISA’s suboptimal solutions with its MILP exact optimal counterparts obtained for small- to medium-size benchmarks of F-JSSP. The AISA’s results were examined further by comparing them with seven of the best-performing meta-heuristics applied to the same benchmark. The performed comparative analysis demonstrated the superiority of the developed AISA algorithm. An industrial problem in a mould- and die-making shop was used for verification.     

Nimesulide prevents lipopolysaccharide-induced elevation in plasma tumor necrosis factor-alpha in rats

The present study was undertaken to test the hypothesis of possible inhibitory effect of nimesulide (4-nitro-2-phenoxymethane-sulfoxide) on plasma TNF-alpha level. Male Sprague-Dawley rats were injected intraperitoneally (i.p.) with E. coli lipopolysaccharide (LPS; 1 mg/kg), which resulted in a dramatic increase in plasma TNF-alpha level peaked 60 min post injection (3890+/-280 pg/ml, compared to undetectable values in the control group). Nimesulide (30 mg/kg) injected i.p. 60 min prior to LPS, prevented LPS-induced elevation in plasma TNF-alpha. Nimesulide alone did not alter circulating levels of TNF-alpha. It appears that the anti-inflammatory properties of nimesulide may in part be attributed to its inhibitory effect on TNF-alpha production.     

Investigation of the iron doping on the structural,optical, and magnetic properties of Fe-doped ZnO nanoparticles synthesized by sol–gel method

Journal of Materials Science: Materials in Electronics - In this work, the compatibility of zinc oxide for spintronic applications motivated the development of single-phase Fe/ZnO nanostructures by...     

In-plane shear properties of unidirectional glass fiber (U)/random glass fiber (R)/epoxy hybrid and non-hybrid composites

The in-plane shear properties (shear strength τ_xy and shear modulus G_xy) of unidirectional glass fiber (U)/random glass fiber (R)/epoxy hybrid and non-hybrid composites have been investigated experimentally and theoretically. The effect of stacking sequence and random fiber relative volume fraction (V_fR/V_fT) in hybrid composites were reported. Laminates were fabricated by hand lay-up technique with a total of 5 plies, by varying the number and position of random glass layers so as to obtain four different hybrid laminates; i.e. [0.5R/U/U]_S, [U/0.5R/U]_S, [U/U/0.5R]_S, and [U/R/U/R/U]. All unidirectional fiber laminate [U]₅ and another of all random fiber laminate [R]₅ were also fabricated for comparison purpose. The average thickness of the manufactured laminates is 5.5 ± 0.2 mm and the total fiber volume fraction (V_fT) is 37%. Failure modes of all specimens were investigated. Results indicated that the in-plane shear properties (shear strength τ_xy and shear modulus G_xy) of unidirectional fiber composite can be considerably improved by incorporation of random glass fiber and forming hybrid composites.     

Preparation and evaluation of some water‐soluble polyester surfactants

A novel series of water‐soluble polyester surfactants were prepared by the polymerization of bis‐1,4‐(dicarboxymethoxy) benzene, maleic anhydride, and oxypropylated 1,4‐butane diol (IP₁–IP₅) or oxypropylated 1,6‐hexane diol (IIP₁–IIP₅). The unique structural features of these surfactants were confirmed by IR and ¹H‐NMR spectra. These water‐soluble polyester surfactants exhibited excellent surface tension, interfacial tension, low foaming, good emulsifier capability, and good biodegradability in river water, solubilization, wetting, and dispersant properties for applied dyes. The antimicrobial and antifungal properties of the prepared polyester surfactants were measured and found to be highly active. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3413–3424, 2001