Application of the electrochemical quartz crystal microbalance technique to copper sonoelectrochemistry: Part 1. Sulfate-based electrolytes

The applicability of the electrochemical quartz crystal microbalance technique in an ultrasonic field created by an ultrasound probe is demonstrated for the electrodeposition of copper. Cyclic voltammetry and potentiostatic depositions in acidic sulfate-based copper electrolytes were performed at different ultrasonic intensities. The electrochemical quartz crystal microbalance was operated in ultrasonic fields with intensities up to 30 W cm⁻². For cyclic voltammetry, potential resolved and averaged (apparent) current efficiencies were calculated from mass and charge data in function of the amplitude of the ultrasonic horn. Ultrasound slightly affected the current efficiencies during copper deposition in cyclic voltammetry, but did not change the efficiencies during dissolution. During potentiostatic depositions the current efficiency increased from 84% to almost 100% upon application of ultrasound. Morphology of deposits prepared by potentiostatic depositions was analyzed by scanning electron microscopy, and found to be different at high ultrasonic intensities.     

Designs and investigations of anti-glare blue-tint side-view car mirrors

Recent developments for luxury car industries have been in favor of anti-glare color-tint side-view exterior car mirrors. In this study, we explore the designs, the fabrications, and the investigations of anti-glare blue-tint samples suitable for the side-view car mirrors. With an aid of the thin film design software, the TiO₂-based backside-coated optical systems are prepared by the homemade and the retailed sputtering systems, and examined for the reflection spectra and the chromaticity diagrams. From four major designs of the anti-glare blue-tint mirrors, the ultra-thin metallic layer and the dielectric stack with the bottommost reflective layer offer the blue-tint at 85% highest reflection. Although the design requires only 40 min of the deposition time, the careful control of the ultra-thin metallic film thickness is crucial.     

A taboo search approach for deadlock-free scheduling of automated manufacturing systems

This paper addresses the scheduling problem of a class of automated manufacturing systems. A new manufacturing system model is proposed. In this model, a set of jobs is to be processed and each job requires a sequence of operations. Each operation may need more than one resource. Upon the completion of an operation, resources needed in the next operation of the same job cannot be released and the remaining resources cannot be released until the start of the next operation. The scheduling problem consists in sequencing the operations on the resources in order to avoid deadlocks and to minimize the makespan. The classical disjunctive graph representation is extended to model the scheduling problem. A taboo search algorithm is then proposed using an original neighborhood structure defined by two basic moves: the permutation of disjunctive arcs of critical paths and a deadlock recovery move if the former fails. Numerical results presented in the paper show the efficiency of the proposed algorithm.     

A genetic local search algorithm for minimizing total weighted tardiness in the job-shop scheduling problem

This paper considers the job-shop problem with release dates and due dates, with the objective of minimizing the total weighted tardiness. A genetic algorithm is combined with an iterated local search that uses a longest path approach on a disjunctive graph model. A design of experiments approach is employed to calibrate the parameters and operators of the algorithm. Previous studies on genetic algorithms for the job-shop problem point out that these algorithms are highly depended on the way the chromosomes are decoded. In this paper, we show that the efficiency of genetic algorithms does no longer depend on the schedule builder when an iterated local search is used. Computational experiments carried out on instances of the literature show the efficiency of the proposed algorithm.     

Barrel-like carbon nanoparticles from carbide by catalyst assisted chlorination

The nanostructure of carbon materials synthesised via chlorination of various metal and metalloid carbides and their mixtures has been investigated by low-temperature nitrogen sorption, X-ray powder diffraction and high-resolution electron microscopy techniques. The carbon nanostructure and its crystallinity are strongly affected by transition metal catalysts and synthesis temperature. A clear relationship between carbon nanostructure formation and catalysts concentration revealed that only very low concentration (approximately 1 mg per gram of carbide) of Cobalt (Ni, Fe) in reaction medium supports the conversation of Al₄C₃ to nanobarrel-like carbon nanoparticles.     

Physical and stress-strain properties of wheat (Triticum aestivum) kernel

BACKGROUND: Two hard wheat varieties and one soft variety grown under the same agroecological conditions were analyzed for their physical and uniaxial stress–strain compression properties. RESULTS: The physical properties of wheat kernel were determined at a moisture content of 0.13 kg kg^?1 (wet basis), whereas the stress–strain compression test was conducted at a kernel moisture content from 0.082 to 0.433 kg kg^?1. Mean kernel lengths were 5.46 (5.37 and 5.38) mm, widths were 2.56 (2.47 and 2.62) mm and thicknesses were 2.12 (2.18 and 2.43) mm for Simonida, Dragana and NS 40S cultivars, respectively. Bulk densities were 791.34 (Simonida), 788.51 (Dragana) and 731.77 kg m^?3 (NS 40S). The force at the yield point was 241.46 N for Dragana (moisture content 0.133 kg kg^?1), 244.30 N for Simonida (0.136 kg kg^?1) and 164.90 N for NS 40S (0.433 kg kg^?1). CONCLUSION: The width and thickness of the analyzed kernels were small compared with the length, and bulk densities were also moderate. The yield point force values of the two hard varieties were 2.2 times higher than the values of the soft variety, at a moisture content of 0.136 kg kg^?1 for Simonida, 0.133 kg kg^?1 for Dragana and 0.141 kg kg^?1 for NS 40S. Copyright © 2011 Society of Chemical Industry     

Characterization of inhomogeneity in TiO2 thin films prepared by pulsed dc reactive magnetron sputtering

This article discusses an analytical method for characterizations of TiO₂ thin films and determinations of the degree of their inhomogeneity. The TiO₂ films were prepared by a pulsed dc magnetron sputtering with an operating pressure as a main experimental parameter. The obtained films were primarily characterized for film crystallinity, microstructures and optical properties by spectroscopic ellipsometry. The measured ellipsometric data were analyzed by the single-, the double, and the triple-layer models in order to match with the inhomogeneous film structure proposed in the Thornton structure zone model. The results were then compared with those obtained from grazing-incidence X-ray diffraction, field-emission scanning electron microscopy and high-resolution transmission electron microscopy. The study revealed that the pulsed dc sputtered TiO₂ films could be best described by the inhomogeneous triple-layer physical model. Although the films deposited at lower operating pressure had a dense structure with a mirror-like surface topography, the films deposited at higher operating pressure had the porous structure with the rough surface and the void.     

Mg 2+-doped GaN nanoparticles as blue-light emitters: a method to avoid sintering at high temperatures

Bright blue-light emission at 410 nm is observed from Mg(2+)-doped GaN nanoparticles prepared by the nitridation of Ga(2)MgO(4) nanoparticles at 950 degrees C. The sintering of these nanoparticles during high-temperature nitridation was prevented by mixing the Ga(2)MgO(4) precursor nanoparticles with La(2)O(3) as an inert matrix before the nitridation process. The Mg(2+)-doped GaN nanoparticles were isolated from the matrix by etching with 10 % nitric acid. The Mg(2+)-doped GaN nanoparticles were characterized by photoluminescence, atomic force microscopy, X-ray diffraction, and IR analyses.