Evaluation of the genetic algorithm parameters on the optimization performance: a case study on pump-and-treat remediation design

In this study, the impacts of different crossover and encoding schemes on the performance of a genetic algorithm (GA) in finding optimal pump-and-treat (P&T) remediation designs are investigated. For this purpose, binary and Gray encodings of the decision variables are tested. Uniform and two-point crossover schemes are evaluated for two different crossover probabilities. Analysis is performed for two P&T system optimization scenarios. Results show that uniform crossover operator with Gray encoding outperforms the other alternatives for the complex problem with higher number of decision variables. On the other hand, when a simpler problem, which had a lower number of decision variables, is solved, the efficiency of GA is independent of the encoding and crossover schemes.     

Surface wave scattering by a rectangular impedance cylinder located on a reactive plane

The electromagnetic scattering of the surface wave by a rectangular impedance cylinder located on an infinite reactive plane is considered for the case that the impedances of the horizontal and vertical sides of the cylinder can have different values. Firstly, the diffraction problem is reduced into a modified Wiener–Hopf equation of the third kind and then solved approximately. The solution contains branch‐cut integrals and two infinite sets of constants satisfying two infinite systems of linear algebraic equations. The approximate analytical or numerical evaluations of corresponding integrals and numerical solution of the linear algebraic equation systems are obtained for various values of parameters such as the surface reactance of the plane, the vertical and horizontal wall impedances, the width and the height of the cylinder. Copyright © 2004 John Wiley & Sons, Ltd.     

Dissolution kinetics of copper(II) oxide in water saturated by sulphur dioxide

The dissolution and the kinetics of dissolution of cooper(II) oxide in water saturated by sulphur dioxide has been studied. In the experiments, the particle size, the flow rate of the gas, the solid to liquid ratio, and the reaction temperature have been chosen as parameters, while the stirring rate was held constant. As a result of present experiments, it was observed that the decrease of the particle size, the solid to liquid ratio, and an increase of the reaction temperature increased the dissolution rate. It was also observed that the flow rate of sulphur dioxide in the range of its flow rate values did not affect the dissolution rate. The reaction kinetics of copper(II) oxide according to the heterogeneous reaction models was examined and it was found that the dissolution rate was controlled by chemical reaction. The calculated activation energy is 66.50 kJmol^?1. © 1994 John Wiley & Sons, Inc.     

Influence of chemical effect on the K-shell X-ray production cross-sections and radiative Auger ratios of Zn complexes

In this study, _σK_α${\sigma }_{{\text{K}}_{\mathrm{\alpha }}}$, _σK_β${\sigma }_{{\text{K}}_{\mathrm{\beta }}}$ production cross-sections, KLM/K_α and KMM/K_β radiative Auger intensity ratios of Zn in different complexes were measured. The samples were excited by 59.5 keV γ-rays from a ²⁴¹Am annular radioactive source. K X-rays emitted by samples were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV. The charge transfer effects on central Zn atom was investigated by using the behaviors of different ligands in these complexes.     

Temperature dependence of the optical band gap and electrical conductivity of sol-gel derived undoped and Li-doped ZnO films

Undoped and lithium (Li)-doped ZnO films were prepared by sol-gel method using spin coating technique. The effects of Li content on the crystallinity and morphological properties of ZnO films were assessed by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). XRD patterns of the films showed the hexagonal wurtzite type polycrystalline structure and that the incorporation of lithium leads to substantial changes in the structural characteristics of ZnO films. The SEM and AFM measurements showed that the surface morphology of the films was affected from the lithium incorporation. The wrinkle network was observed on the surface from both SEM and AFM results for undoped ZnO. The wrinkle structure disappeared with increasing Li content. The absorption spectra of the ZnO and 5% Li-doped ZnO (LZO5) films were carried out between 140 and 400 K temperatures. The optical band gap of ZnO and LZO5 films (calculated at various temperatures) showed a linear dependence on the temperature. The absolute zero value optical band gap and the rate of change of the band gap with temperature of the ZnO and LZO5 films were found to be 3.339 and 3.322 eV, and 2.95 × 10⁻⁴ and 1.60 × 10⁻⁴ eV/K, respectively. The transport mechanisms in the ZnO and LZO5 films have been investigated by analyzing of the temperature (80-300 K) dependence of the conductivity. The activation energies of the ZnO film increased with Li content.     

Evidence for the emission of 'alkali-metal-noble-gas' van der Waals molecules from cavitation bubbles

Visible emission spectra in the vicinity of resonance lines of alkali metals were recorded from acoustically cavitating aqueous and 1-octanol solutions (acoustic frequency: 20 kHz; solutes: Ar (or Kr), NaCl, RbCl or rubidium 1-octanolate). The maximum intrabubble density deduced from line shift data was approximately 5 +/- 0.7 x 10(26) m-3, i.e. approximately 18 +/- 2 amagats. It is demonstrated that (i) the emission from alkali metals arose from the gas phase of bubbles, (ii) the blue satellite and line distortions were induced, respectively, by B2 sigma+ - X2 sigma+ and A2II - X2 sigma+ transitions of 'alkali-metal/rare-gas' van der Waals molecules and (iii) excitation/de-excitation mechanisms are chemiluminescent in essence.     

Plasma-spectroscopic studies on alternating current arc discharges in methane

Plasma spectroscopic studies on alternating current arcs in methane were performed with a view to pyrolytical processes leading to the formation of pyrolytic carbon. Operating parameters such as current intensity, electrode gap and methane filler gas pressure were varied. Excitation temperatures were measured from the rotational levels of CH and C₂ radicals. Temperature determinations were carried out for various arcing periods and in different zones in the plasma column. The validity of the Boltzmann equation was proved. The electron number density was determined from the Stark broadening of the H_β-line.     

OH/D A2sigma(+)-X2pi(i) rovibronic transitions in multibubble sonoluminescence

Multibubble sonoluminescence spectra were recorded in the 300-350 nm wavelength range in the case of H(2)O/Ar, D(2)O/Ar and H(2)O/Kr solutions (acoustic frequency: 20 kHz; spectral resolution optimized to 0.34 nm). Three groups of rotational components (R(1)/R(2), Q(1)/Q(2) and P(1)/P(2)) were identified in the OH/D A2sigma(+)-X2pi(i) (0,0) transitions via the substitution of H(2)O for D(2)O. The congestion of bands and the origin of a red shading extending up to 350 nm are broached.     

Chlorine incorporation in silicon films deposited by low-pressure rf discharges in gas mixtures of SiCl4+H2+Ar

Silicon films were deposited from tetrachlorosilane by its dissociation in argon and hydrogen rf plasma at a pressure of 2 Torr. The concentration of chlorine incorporated in the films was found to be dependent on the macrovariables of the plasma such as power input and substrate position in the plasma reactor. Mass spectrometric measurements of the plasma showed that the concentration of HCl in the plasma was strongly dependent on the power input and on position in the plasma along the gas stream. At high input powers the HCl formed in the plasma dissociates to free radicals, contributing to a recombination process in the gas phase and codeposition with silicon on the substrate. The correlation between the HCl reactions in the plasma and the incorporation of Cl in the deposit is shown.Presented in part at the 6th ISPC, Montreal, p. 820.     

Safflower seed oil of Turkish origin as a diesel fuel alternative

Applied Biochemistry and Biotechnology - Among the biomass resources, vegetable oils seem to have the potential to be used as fuel alternatives for diesel engines. The major restricting factor in...