Ant colony optimization for power plant maintenance scheduling optimization—a five-station hydropower system

A number of algorithms have been developed for the optimization of power plant maintenance schedules. However, the true test of such algorithms occurs when they are applied to real systems. In this paper, the application of an Ant Colony Optimization formulation to a hydropower system is presented. The formulation is found to be effective in handling various constraints commonly encountered in practice. Overall, the results obtained using the ACO formulation are better than those given by traditional methods using engineering judgment, which indicates the potential of ACO in solving realistic power plant maintenance scheduling problems.     

Generation of hyperchaos from the Chen–Lee system via sinusoidal perturbation

A system with more than one positive Lyapunov exponent can be classified as a hyperchaotic system. In this study, a sinusoidal perturbation was designed for generating hyperchaos from the Chen–Lee chaotic system. The hyperchaos was identified by the existence of two positive Lyapunov exponents and bifurcation diagrams. The system is hyperchaotic in several different regions of the parameters c, ε, and ω. It was found that this method not only can enhance or suppress chaotic behavior, but also induces chaos in non-chaotic parameter ranges. In addition, two interesting dynamical behaviors, Hopf bifurcation and intermittency, were also found in this study.     

Polyplatinayne/polyoxometalate composite Langmuir‐Blodgett films: Preparation,structural characterization,and potential optoelectronic applications

A new family of organometallic/inorganic composite Langmuir‐Blodgett (LB) films consisting of rigid‐rod polyplatinayne polymer ([Pt‐T(OMe‐Fl)T]_∞ or [Pt‐T(F‐Fl)T]_∞, where the triplet bonds are abbreviated by T, and fluorene ring by Fl) as the π‐conjugated organometallic molecule, polyoxometalate (POM, POM = K₃PMo₁₂O₄₀, H₃PW₁₂O₄₀, or H₆P₂W₁₈O₆₂) of the Keggin and Dawson structures as the inorganic component, and dimethyldioctadecylammonium bromide (DODA) or a mixture of octadecanoic acid (OA) and docosanoic acid (DA) as the auxiliary film‐forming agent were prepared and characterized by π–A isotherms, UV–Vis absorption spectra, photoluminescence spectra, atomic force microscopy imaging, scanning tunneling microscopy, and low‐angle X‐ray diffraction. Our experimental results indicate that steady, even, and ordered Langmuir and LB films are formed in pure water and polyoxometalate subphases. It was shown that the POM molecules are probably embedded inside the polyplatinayne molecules in the LB film structure and they can quench the luminescence of the Pt polyyne. These Pt‐polyyne based LB films display interesting electric conductivity behavior. [Pt‐T(OMe‐Fl)T]_∞/DODA/HPW₁₂ monolayer film shows a good electrical conductivity, and the tunneling current amounts to ±100 nA when the voltage is set at ±8 V. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3193–3206, 2008     

<Emphasis Type="Italic">k</Emphasis>-factors in regular graphs

Plesnik in 1972 proved that an （m - 1）-edge connected m-regular graph of even order has a 1-factor containing any given edge and has another 1-factor excluding any given m - 1 edges. Alder et al. in 1999 showed that if G is a regular （2n ＋ 1）-edge-connected bipartite graph, then G has a 1-factor containing any given edge and excluding any given matching of size n. In this paper we obtain some sufficient conditions related to the edge-connectivity for an n-regular graph to have a k-factor containing a set of edges and （or） excluding a set of edges, where 1 ≤ k ≤n/2. In particular, we generalize Plesnik＇s result and the results obtained by Liu et al. in 1998, and improve Katerinis＇ result obtained 1993. Furthermore, we show that the results in this paper are the best possible.     

A sodium ion selective optode based on fluorescein octadecyl ether octadecyl ester and application in beverage and urine assay

A fast responsive sodium ion selective fluorescent optode membrane mounted on an optical fiber has been developed. The sensing membrane contained fluorescein octadecyl ether octadecyl ester (FODEE), potassium tetrakis(4-chlorophenyl) borate (KTpClPB) and a calix[4]arene tetraester in a plasticized poly(vinyl chloride) (PVC) matrix. It exhibited a reversible response to Na⁺ in 0.5 mol/l of HCl in the concentration range of 1.0×10⁻⁶ to 0.1 mol/l. The selectivity, response time, reproducibility and lifetime of the optode membrane were discussed. The practical use of this sensor was demonstrated by real sample analysis in complex sample solutions such as beverage and urine samples.     

Integral equation formulation for buoyancy-driven convection problems

An integral equation formulation for buoyancy-driven convection problems is developed and illustrated. Buoyancy-driven convection in a bounded cylindrical geometry with a free surface is studied for a range of aspect ratios and Nusselt numbers. The critical Rayleigh number, the nature of the cellular motion, and the heat transfer enhancement are computed using linear theory. Green's functions are used to convert the linear problem into linear Fredholm integral equations. Theorems are proved which establish the properties of the eigenvalues and eigenfunctions of the linear integral operator which appears in these equations.     

Functionalized Alkynylplatinum(II) Polypyridyl Complexes for Use as Sensitizers in Dye‐Sensitized Solar Cells

A series of platinum(II) alkynyl‐based sensitizers has been synthesized and found to show light‐to‐electricity conversion properties. These dyes were developed as sensitizers for the application in nanocrystalline TiO₂ dye‐sensitized solar cells (DSSCs). Their photophysical and electrochemical properties were studied. The excited‐state property was probed using nanosecond transient absorption spectroscopy, which showed the formation of a charge‐separated state that arises from the intramolecular photoinduced charge transfer from the platinum(II) alkynylbithienylbenzothiadiazole moiety (donor) to the polypyridyl ligand (acceptor). A lifetime of 3.4 μs was observed for the charge‐separated state. A dye‐sensitized solar cell based on one of the complexes showed a short‐circuit photocurrent of 7.12 mA cm^?2, an open circuit voltage of 780 mV, and a fill factor of 0.65, thus giving an overall power conversion efficiency of 3.6 %.