Corrosion Protection of Aluminum Alloy AA7020 in NaCl Solution by Hybrid Sol–Gel Coatings

Protection of Metals and Physical Chemistry of Surfaces - In this study, two different hybrid sols as tetraethyl orthosilicate/(3-Glycidyloxypropyl) trimethoxysilane (TEOS/GPTMS) and tetrapropyl...     

All‐carbon hybrids for high performance supercapacitors

A hybrid nanostructure with partially reduced graphene oxide (rGO) and carbon nanofibers (CNFs) was fabricated and used as supercapacitor electrodes. A straightforward, environmentally friendly, and low‐cost microwave‐assisted reduction process was developed for the synthesis of rGO/CNF hybrid structures. The fabricated supercapacitor devices showed a specific capacitance of 95.3 F g^?1 and a superior long‐term cycling stability. A capacitance retention of more than 97% after 11 000 galvanostatic charge discharge cycles was obtained. These and other results reported in this paper indicate that high‐rate, all‐carbon, rGO/CNF hybrid nanostructures are highly promising supercapacitor electrode materials.     

ZnO Nanorods as Antireflective Coatings for Industrial‐Scale Single‐Crystalline Silicon Solar Cells

In this work, both planar and textured, industrial scale (156 mm × 156 mm) single‐crystalline silicon (Si) solar cells have been fabricated using zinc oxide (ZnO) nanorods as antireflection coating (ARC). ZnO nanorods were grown in a few minutes via hydrothermal method within a commercially available microwave oven. Relative improvement in excess of 65% in the reflectivity was observed for both planar and textured Si surfaces. Through ZnO nanorods, effective lifetime (τ_eff) measurements were presented to investigate the surface passivation property of such an ARC layer. ZnO nanorods increased the τ_eff from 9 to 71 μs at a carrier injection level of 10¹⁵ cm^?3. Increased carrier lifetime revealed the passivation effect of the ZnO nanorods in addition to their ARC property. 33% and 16% enhancement in the photovoltaic conversion efficiency was obtained in planar and textured single‐crystalline solar cells, respectively. Our results reveal the potential of ZnO nanorods as ARC that can be deposited through simple solution‐based methods and the method investigated herein can be simply adapted to industrial scale fabrication.     

Electrochemical and morphological assessments of inhibition level of 8-hydroxylquinoline for AA2024-T4 alloy in 3.5% NaCl solution

The corrosion inhibition of AA2024-T4 in 3.5% NaCl solution by 8-hydroxylquinoline (8-HQ) was investigated by potentiodynamic polarisation (PDP), electrochemical impedance spectroscopy and dynamic electrochemical impedance spectroscopy. Experimental results were supported with scanning electron microscopy (SEM), atomic force microscopy and Fourier transform-infrared (FTIR) spectroscopy analysis. It was found that 8-HQ molecules adsorbed on the alloy surface and protected it against corrosion. SEM, energy dispersive spectroscopy, and FTIR results confirm the adsorption of 8-HQ molecules on AA2024-T4. The inhibition efficiency of 8-HQ is found to increase with increase in concentration and the highest concentration studied (0.05 M) offered corrosion inhibition efficiency of 84%. PDP results show that 8-HQ acts as mixed type inhibitor in the studied medium.     

Wearable supercapacitors based on nickel tungstate decorated commercial cotton fabrics

Symmetric supercapacitors (SSCs) with remarkable energy storing capability, high specific power as well as long-term cyclic stability were fabricated from nickel tungstate (NiWO₄) @ nickel oxide (NiO_x) decorated commercial cotton fabrics (CCFs). A commercial cotton-based textile was first made conductive by the state of the art ultrasonic spray coating method. This was followed by chemical and electrochemical processes to decorate activated CCFs with NiO_x and NiWO₄, respectively. The assembled SSCs had the merit of high specific energy of 12 μWh cm⁻² at a specific power of 69 μW cm⁻² while showing reasonable cyclic stability. Fabricated devices retained over 80% of their initial capacitance after 5500 continuous charge/discharge cycles. The flexibility of the devices was investigated under bending, twisting, and folding providing reliable evidence on the wearability of the fabricated SSCs. Cyclic voltammograms of the fabricated NiWO₄@NiO_x@CCF SSCs showed only a slight change and retained over 95% of the capacitance under bending and folding. The fabricated NiWO₄@NiO_x@CCF SSCs, in this regard, are promising energy storage systems to power up high-performance wearable electronics.     

Rapid synthesis of aligned zinc oxide nanowires

A solution growth approach for zinc oxide (ZnO) nanowires is highly appealing because of the low growth temperature and possibility for large area synthesis. Reported reaction times for ZnO nanowire synthesis, however, are long, spanning from several hours to days. In this work, we report on the rapid synthesis of ZnO nanowires on various substrates (such as poly(ethylene terephthalate) (PET), silicon and glass) using a commercially available microwave oven. The average growth rate of our nanowires is determined to be as high as 100?nm?min(-1), depending on the microwave power. Transmission electron microscopy analysis revealed a defect-free single-crystalline lattice of the nanowires. A detailed analysis of the growth characteristics of ZnO nanowires as functions of growth time and microwave power is reported. Our work demonstrates the possibility of a fast synthesis route using microwave heating for nanomaterials synthesis.     

The prevalence and molecular typing of Clostridium perfringens in ground beef and sheep meats

This study was aimed at the investigation of the prevalence of Clostridium perfringens in ground beef and sheep meats and to detect the cpa, cpb, etx, iA, cpe and cpb2 toxin genes by multiplex PCR. Obtained from retail markets and butchers, 100 ground meat samples, 50 of which were beef and 50 of which were sheep meat samples, were examined. Out of the 50 ground beef samples 48 (96 %) and out of the 50 ground sheep meat samples 44 (88 %) were contaminated with C. perfringens. According to microscopic examination and the results of biochemical tests, 262 positive isolates obtained from these samples were identified as C. perfringens. Multiplex PCR results demonstrated that, out of the 262 isolates, 203 (77.4 %) possessed only the cpa gene (type A), while 20 (7.6 %) carried the cpa and cpb2 toxin genes (type A-cpb2), and 6 (2.2 %) the cpa and cpe toxin genes (type A-cpe). Furthermore, it was determined that, out of the 262 C. perfringens isolates, 4 (1.5 %), 10 (3.8 %) and 19 (7.2 %) were of the types B, C and D, respectively.     

Design criteria for transparent single-wall carbon nanotube thin-film transistors

A study based on two-dimensional percolation theory yielding quantitative parameters for optimum connectivity of transparent single-wall carbon nanotube (SWNT) thin films is reported. Optimum SWNT concentration in the filtrated solution was found to be 0.1 mg/L with a volume of 30 mL. Such parameters lead to SWNT fractions in the films of approximately Phi = 1.8 x 10(-3), much below the metallic percolation threshold, which is found to be approximately PhiC = 5.5 x 10(-3). Therefore, the performance of transparent carbon nanotube thin-film transistors is limited by the metallic SWNTs, even below their percolation threshold. We show how this effect is related to hopping or tunneling between neighboring metallic tubes.