Assessment of polyester and polyvinylester coatings in a simulated FGD scrubbing liquid with EIS

Abstract

Corrosion behaviours of carbon steel coated with polyester and polyvinylester in a simulated flue gas desulphurisation (FGD) fluid (i.e., a mixture of H₂SO₄ and 0.1 wt% Fe₂(SO₄)₃ at pH=2) have been investigated with electrochemical impedance spectroscopy (EIS). The protective nature of the coatings at 25°C has been observed in the following order: polyvinylester primer >> polyvinylester topcoat > polyester topcoat > polyester primer. Coating deterioration occurred and the coating deterioration rate accelerated with increasing temperatures upto 85°C. However, the corrosion resistance sequence has remained the same. Equivalent circuits are suggested for various coatings to discuss their mechanisms in this work.     

A hybrid swarm intelligence algorithm for the travelling salesman problem

Abstract: We present a hybrid model named HRKPG that combines the random‐key search method and an individual enhancement scheme to thoroughly exploit the global search ability of particle swarm optimization. With a genetic algorithm, we can expand the area of exploration of individuals in the solution space. With the individual enhancement scheme, we can enhance the particle swarm optimization and the genetic algorithm for the travelling salesman problem. The objective of the travelling salesman problem is to find the shortest route that starts from a city, visits every city once, and finally comes back to the start city. With the random‐key search method, we can search the ability of the particle and chromosome. On the basis of the proposed hybrid scheme of HRKPG, we can improve solution quality quite a lot. Our experimental results show that the HRKPG model outperforms the particle swarm optimization and genetic algorithm in solution quality.     

New configuration for realizing universal voltage-mode filter usingtwo current feedback amplifiers

A new universal biquadratic filter configuration using two current-feedback amplifiers (CFAs) is presented. The circuit has three inputs and one low-impedance output and can realize all the standard filter functions, that is, highpass, bandpass, lowpass, notch, and allpass filters, without changing the passive elements. The proposed circuit has no requirements for component matching conditions and uses only four passive components. The center frequency and bandwidth can be orthogonally controllable. Also, the active and passive sensitivities are low     

Thermal Management and Interfacial Properties in High-Power GaN-Based Light-Emitting Diodes Employing Diamond-Added Sn-3 wt.%Ag-0.5 wt.%Cu Solder as a Die-Attach Material

The thermal management of high-power GaN-based light-emitting diodes (LEDs) soldered with Sn-3 wt.%Ag-0.5 wt.%Cu (SAC305) solder and diamond-added SAC305 solder was evaluated. Diamond addition was found to significantly reduce the surface temperature and total thermal resistance of the LEDs, revealing that diamond-added SAC305 solder is a promising die-attach material for high-power LED packaging. Interfacial reactions in the LED solder joints were also investigated. The thin Au wetting layer in the chip’s backside metallization was rapidly consumed in the initial stage of reflow, forming an AuSn₄ phase at the interface. Subsequently, the AuSn₄ phase detached from the interface, leading to dewetting of the SAC305 solder from the LED chip. To avoid dewetting, a new backside metallization of LED chips should be developed for SAC305 solder.     

Scanning waveform analysis of a room-temperature-probe SQUID NDE system

A room-temperature-probe SQUID NDE system with high mobility and excellent spatial resolution has been developed for detecting the internal cracks of metallic material. Here, the sensing probe is composed of quadruple excitation coils and double D-shape pickup coils. It is connected to the input coil surrounding the SQUID sensor to transfer a magnetic field of eddy current. Following the previous demonstration of its good spatial resolution and high sensitivity, a signal mechanism for the scanning waveform is further proposed in this study to explain the scanning non-directionality of the system and analyze the internal cracks. Both fine and wide single cracks and multi-cracks with dense and spare intervals are valid. Moreover, the model is in good agreement with the test results.     

Poly(ethylene terephthalate)/poly(ethylene glycol‐co‐1,3/1,4‐cyclohexanedimethanol terephthalate)/clay nanocomposites: Effects of biaxial stretching

In this study, we fabricated poly(ethylene terephthalate) (PET)/clay, PET/poly(ethylene glycol‐co‐1,3/1,4‐cyclohexanedimethanol terephthalate) (PETG), and PET/PETG/clay nanocomposite plates and biaxially stretched them into films by using a biaxial film stretching machine. The tensile properties, cold crystallization behavior, optical properties, and gas and water vapor barrier properties of the resulting films were estimated. The biaxial stretching process improved the dispersion of clay platelets in both the PETG and PET/PETG matrices, increased the aspect ratio of the platelets, and made the platelets more oriented. Thus, the tensile, optical, and gas‐barrier properties of the composite films were greatly enhanced. Moreover, strain‐induced crystallization occurred in the PET/PETG blend and in the amorphous PETG matrix. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42207.     

Effective Control Charts for Monitoring Multivariate Process Dispersion

When monitoring process dispersion, it is common to pay more attention to dispersion increases than to decreases for practical reasons. Nonetheless, it is also important to detect dispersion decreases for two reasons: (i) it deserves further investigations as to why the process has improved; and (ii) if the process has changed, the settings of the control chart would need to be adjusted for effective future monitoring. In this paper, we first propose an effective control chart for detecting multivariate dispersion decreases in phase II process monitoring, which is constructed using the same approach as that of the one‐sided likelihood‐ratio‐test‐based multivariate chart proposed recently in the literature for detecting dispersion increases. We then discuss a combined charting scheme by combining these two one‐sided charts for detecting either dispersion increases or decreases. Comparative simulation studies show that the proposed combined control charting scheme outperforms several existing two‐sided control charts in terms of the average run length when the process dispersion indeed increases or decreases. Two real‐life examples are presented to demonstrate the applicability of the proposed charts. Copyright © 2011 John Wiley & Sons, Ltd.     

Preparation and characterization of functional fabrics from bamboo charcoal/silver and titanium dioxide/silver composite powders and evaluation of their antibacterial efficacy

Bamboo charcoal supporting silver (BC/Ag) and titanium dioxide supporting silver (TiO₂/Ag) were prepared by activation and chemical reduction. The BC/Ag and TiO₂/Ag composites were characterized by silver particle size and distribution and antibacterial properties. The pore and surface properties were studied in terms of BET volumetric measurement with nitrogen adsorption, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The antibacterial effects of the BC/Ag and TiO₂/Ag composite powders were assessed from the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs), and an excellent antibacterial performance was discovered. Moreover, these composite powders were deposited via immersion coating onto fabrics (nonwoven and carbon fibers) to improve the antibacterial efficacy and to act as a biologically-protective material. The antibacterial activities of the fabrics supported by BC/Ag and TiO₂/Ag were studied in zone of inhibition and plate counting tests against Gram-positive Staphylococcus aureus ME/GM/TC Resistant, Bacillus subtilis, Candida albicans, Gram-negative Pseudomonas aeruginosae (CTZ&EM&GM) Res. Clin. Isol., Escherichia coli Juhl, and Klebsiella pneumoniae. The results showed that fabric-BC/Ag and fabric-TiO₂/Ag possess a strong antibacterial activity and an inhibitory effect on the growth of these bacteria and are therefore believed to have great potential for use as antibacterial fabrics.     

Development of an anti-influenza drug screening assay targeting nucleoproteins with tryptophan fluorescence quenching

Recent studies have shown that NP (nucleoprotein), which possesses multiple functions in the viral life cycle, is a new potential anti-influenza drug target. NP inhibitors reliably induce conformational changes in NPs, and these changes may confer inhibition of the influenza virus. The six conserved tryptophan residues in NP can be used as an intrinsic probe to monitor the change in fluorescence of the tryptophan residues in the protein upon binding to an NP inhibitor. In the present study, we found that the fluorescence of recombinant NP proteins was quenched following the binding of available NP inhibitors (such as nucleozin) in a concentration- and time-dependent manner, which suggests that the inhibitor induced conformational changes in the NPs. The minimal fluorescence-quenching effect and weak binding constant of nucleozin to the swine-origin influenza virus H1N1pdm09 (SOIV) NP revealed that the SOIV is resistant to nucleozin. We have used the fluorescence-quenching property of tryptophans in NPs that were bound to ligands in a 96-well-plate-based drug screen to assess the ability of promising small molecules to interact with NPs and have identified one new anti-influenza drug, CSV0C001018, with a high SI value. This convenient method for drug screening may facilitate the development of antiviral drugs that target viruses other than the influenza virus, such as HIV and HBV.