Lamellar eutectic growth with anisotropic interphase boundaries: Experimental study using the rotating directional solidification method

We report on an experimental study of the effects of interphase boundary anisotropy on eutectic microstructures using a new methodology called rotating directional solidification (RDS), which consists of rotating a thin sample with respect to a fixed unidirectional thermal gradient. The systems used are thin, large eutectic grains of the CBr₄–C₂Cl₆ and In–In₂Bi lamellar eutectic alloys. The shape of the observed RDS lamellar trajectories turns out to be a reproducible eutectic-grain-dependent feature, in agreement with the theoretical prediction that these trajectories are approximately homothetic to the Wulff form of the interphase boundary in the sample plane. We show that different modes of lamellar growth, ranging from quasi-isotropic to (crystallographically) locked, exist in different eutectic grains of the two alloys studied. A detailed characterisation of these modes is given, with particular attention to the as-yet poorly understood aspects of locked lamellar growth.     

Novel mixed ligand complexes of Co(II), Ni(II), Cu(II), and Zn(II) with 1,10-phenanthroline and acesulfame. Synthesis,structural analysis and hydrogen adsorption study

Four novel metal organic framework (MOF) structures containing acesulfame (ace) and 1,10-phenanthroline (phen) ligands of Co²⁺, Ni²⁺, Cu²⁺ and Zn²⁺ metal cations were synthesized. The crystal structure analysis of three compounds (1, 2, and 3) was also performed. The structural formula for complex 4 is proposed based on spectroscopic and thermal analysis data. It has been determined that structures 1, 2, and 4 are in a distorted octahedral geometry. It has been suggested that the charge balance of the coordination sphere with 2+ is provided by two monoanionic ace ligands located outside the coordination sphere as counter-ion. In structure 3, there are two Cu^II metal cations, two phen ligands coordinated as bidentate to each metal cation and ace ligand that provides monoanionic-monodentate coordination. The Cu²⁺ cation has distorted bipyramidal geometry. The maximum hydrogen gas adsorption has been found 1.4575 mL/g (0.046 wt%) for the Ni complex.     

A theory of thin lamellar eutectic growth with anisotropic interphase boundaries

We present a semiempirical theory of the effects of an orientation dependence of the surface free energy of interphase boundaries (interphase boundary anisotropy) on lamellar eutectic growth in thin samples. We show that, to a good approximation, thin lamellar eutectic patterns with a strong interphase boundary anisotropy travel along the growth front at such a velocity – or, equivalently, at such an inclination angle of the lamellae left behind in the solid – that the surface tension force of the interphase boundary is nearly parallel to the applied thermal gradient. This explains, among other things, the crystallographic locking of lamellar eutectic patterns that occurs in those eutectic grains, which have cusp singularities in the Wulff plot of the interphase boundary. Based on this theory, we show that the rotating directional solidification method, by which a thin sample is rotated with respect to a fixed unidirectional thermal gradient, must yield eutectic lamellae whose trajectories are nearly homothetic to the two-dimensional Wulff form of the interphase boundary. This opens up new possibilities for the experimental study of interphase boundary anisotropy in eutectic alloys.     

Neural network and fuzzy logic-based hybrid attitude controller designs of a fixed-wing UAV

Neural Computing and Applications - In this paper, a mini unmanned aerial vehicle (UAV) is planned to be used in applications such as spraying pesticide and weed control in agricultural areas....     

Comparison of single and joint effects of Zn and Cu in continuous flow and batch reactors

BACKGROUND: Microbial behavior in batch reactors may be different from that in continuous flow reactors, which is expected to affect microbial response to heavy metal exposure. Four parallel continuous flow reactors and batch growth tests were used to investigate the single and joint toxicity of Zn and Cu to Artrobacter sp. JM018. RESULTS: The results indicated that Cu is more toxic than Zn under all conditions. In the batch reactors, all Zn concentrations showed a stimulatory effect on microbial growth. However in the continuous system, 125 µmol L^?1 Zn exposure produced inhibition. In the case of mixed Zn and Cu exposures in the batch system, the presence of Zn reduced the severity of Cu inhibition, with a net impact of reduced growth in all cases, whereas in the continuous system microbial growth and substrate utilization rates sharply decreased and ceased. CONCLUSION: The results clearly showed that growth in batch reactors underestimated significantly the heavy metal inhibition, compared with the continuous system. Therefore, the results of batch reactor tests should not be used directly when heavy metal inhibition is to be interpreted for continuous flow systems. Copyright © 2011 Society of Chemical Industry