A Study on Effect of Waviness on Mechanical Properties of Multi-Walled Carbon Nanotube/Epoxy Composites Using Modified Halpin–Tsai Theory

In order to improve the precision in prediction of mechanical properties of multi-walled carbon nanotubes (MWNTs)/epoxy composites, the effect of waviness of nanotubes is considered by applying a correction factor to a modified Halpin–Tsai equation. Data validation was carried out through the comparison of theoretical data with real mechanical test results obtained by the authors and in the literature. Tensile tests of various weight percents (wt%) of MWNT/epoxy composites were carried out to obtain the mechanical properties of MWNT/epoxy composites. Applicability of the proposed modification of Halpin–Tsai equation was endorsed by the experimental results and was found to be more accurate in comparison with results obtained from the same equation without considering the waviness effect.     

Twin-core fiber optical tweezers: an optimum designation

Optical and Quantum Electronics - Twin-core fiber optical tweezers (TCFOT) can be simulated using finite difference beam propagation method. We chose a tapered TCFOT and calculated its far-field...     

Quantitative Determination of Busulfan in Human Plasma by UPLC

A rapid and reliable UPLC method was developed and validated for the determination of busulfan in human plasma. After protein precipitation, derivatization, and liquid–liquid extraction, separation of derivatized busulfan was achieved on an Acquity BEH C₁₈ column using a gradient mobile phase consisting of a trifluoroacetic acid aqueous solution (0.2%, v/v) and acetonitrile. The column temperature was maintained at 50 °C and UV detection was carried out at 254 nm. The complete analytical run time was 1.3 min, 7-fold faster than our previous LC methodology. Quantification was performed using external standardization and calibration curves were linear (r ≥ 0.999) over the dynamic range of 0.05–5.00 μg mL⁻¹. Intra-day and inter-day coefficients of variation were ≤6.9 and 3.9%, respectively, across the range of concentrations. Accuracy of the analytical method expressed as the relative error percentage was better than 5.4%. LOD and LOQ were 0.013 and 0.025 μg mL⁻¹, respectively. Data obtained using the UPLC method was compared to those obtained from our previously used LC method by Deming regression analysis. The UPLC method was accurate, sensitive, and greatly increased sample analysis throughput as compared to our previous LC methodology allowing for a 4-fold increase in the number of patients who could be monitored during transplant therapy.

     

Nanostructured ternary composites of PPy/CNT/NiFe2O4 and PPy/CNT/CoFe2O4: Delineating and improving microwave absorption

Two different ternary nanocomposites, PPy/CNT/CoFe₂O₄ and PPy/CNT/NiFe₂O₄, were synthesized by in situ polymerization method. The resulting composites were characterized using Fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction. They were evaluated with the aim of investigating microwave absorption properties. The results showed that the value of microwave reflection decreases as that of prepared nanocomposites increases. This happens with increase in the PPy content and polymerization on the surface.     

A complex target terrain SAR raw data generation and evaluation based on inversed equalized hybrid-domain algorithm processing

In this paper, synthetic aperture radar raw data generation of complex target terrain based on inverse equalized hybrid-domain processing technique is proposed. Firstly, the basic synthetic aperture radar (SAR) echo model is derived via spectral analysis of extended chirp scaling. Then, the inverse equalized extended chirp scaling algorithm (ECSA) procedure is applied directly step by step to a real input SAR image in order to generate the raw data of the reference SAR image. The whole raw data generation (RDG) procedure only consists of Inverse Equalized ECSA (IEECSA) without integral equation and computation complexity, which means easier implementation and higher efficiency. By applying the resulted RDG into different image formation algorithms (IFAs), not only the final images are reconstructed but also the resulted RDG is evaluated in practice. Finally, valid image quality assessment techniques are implemented on the reconstructed images. The simulations not only confirm the validity of the proposed RDG method based on inverse equalized hybrid-domain technique but also evaluate the quality metrics of reconstructed images as a method of reliability assurance.     

Gold nanoparticles supported on three‐dimensional nitrogen‐doped graphene: an efficient catalyst for selective aerobic oxidation of hydrocarbons under mild conditions

The development of efficient and selective aerobic oxidation of alkylarenes to form more functional compounds by heterogeneously catalysed routes still presents a great challenge in the fine chemical industry and is a major research topic. In this work, gold nanoparticles supported on three‐dimensional nitrogen‐doped graphene‐based frameworks (Au NPs@3D‐(N)GFs) were successfully synthesized and found to have an impressive performance as bifunctional catalysts (nitrogen dopant as base and gold nanoparticles as active site) in the controlled oxidation of alkylarenes. The catalyst was found to be a simple bench top, stable, recyclable and selective catalytic system for the aerobic oxidation of various types of alkylarenes into their corresponding ketones at room temperature under environmentally friendly conditions with good yields and high selectivity. Copyright © 2015 John Wiley & Sons, Ltd.     

Plasmonic fractals: ultrabroadband light trapping in thin film solar cells by a Sierpinski nanocarpet

Plasmonic Sierpinski nanocarpet as back structure for a thin film Si solar cell is investigated. We demonstrate that ultra-broadband light trapping can be obtained by placing square metallic nanoridges with Sierpinski pattern on the back contact of the thin film solar cell. The multiple-scale plasmonic fractal structure allows excitation of localized surface plasmons and surface plasmon polaritons in multiple wavelengths leading to obvious absorption enhancements in a wide frequency range. Full wave simulations show that 109 % increase of the short-circuit current density for a 200 nm thick solar cell, is achievable by the proposed fractal back structure. The amount of light absorbed in the active region of this cell is more than that of a flat cell with semiconductor thickness of 1,000 nm.