Tensor Properties of Added-mass and Damping Coefficients

It has been shown that in the context of a linear theory for a floating body with six degrees of freedom each of the 6× 6 added-mass and damping matrices contains three distinct Cartesian second-order tensors in regard to translational, rotational and interaction between translational and rotational oscillations. As a result of this, a new technique based on the transformation law of second-order tensors is introduced for motion analysis of offshore platforms which can be used as an alternative to the common methods in offshore engineering.     

Non‐covalent interactions of pyrene end‐labeled star poly(ɛ‐caprolactone)s with fullerene

Pyrene end‐labeled star poly(?‐caprolactone)s (PCLs) with polyhedral oligomeric silsesquioxane (POSS) core were prepared by combination of copper(I)‐catalyzed azide–alkyne cycloaddition (CuAAC) click chemistry and ring‐opening polymerization techniques. First, ?‐caprolactone (?‐CL) is polymerized by using 1‐pyrene methanol as initiator and stannous octoate as catalyst to obtain α‐pyrene‐ω‐hydroxyl telechelic PCL with different chain lengths. Then, its hydroxyl group is converted to acetylene functionality by esterification reaction with propargyl chloroformate. Finally, the CuAAC click reaction of α‐pyrene‐ω‐acetylene telechelic PCL with POSS‐(N₃)₈ leads to corresponding pyrene end‐labeled star‐shaped PCLs. The successful synthesis of pyrene end‐labeled star polymers is clearly confirmed by ¹H‐nuclear magnetic resonance, Fourier transform infrared, gel permeation chromatograph, differential scanning calorimeter, and thermogravimetric analysis. Furthermore, non‐covalent interactions of obtained star polymers with fullerene are investigated in liquid media. Based on Raman spectroscopy and visual investigations, the star polymer having shorter chain length exhibited better and more stable dispersion with fullerene. The amount of pyrene units present per polymer chains can directly influence the dispersion stability of fullerene. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46520.     

A very compact, 0.4 V DTMOS CCII employed in an audio-frequency filter

This paper presents an ultra low-voltage, ultra low-power, very compact, dynamic threshold voltage MOS transistor (DTMOS)-based CCII circuit. The proposed circuit is capable of operating under ± 0.2 V symmetric supply voltages. The circuit topology is very compact and consists of only four DTMOS transistors and four ordinary NMOS transistors. The total power consumption of the circuit is found as only 214 nW while all transistors are working in the subthreshold region. The current conveyor has 570 kHz 3 dB-bandwidth from X to Y terminal for the voltage gain and has low, 0.2 % following error between these terminals for inputs not exceeding ± 60 mV. TSMC 0.18 µm process technology parameters are used in the design of the proposed CCII block which is then employed in an audio-frequency, second-order, band-pass filter configuration where real speech signals are fed to the input of the filter to further investigate its characteristics. Close agreement is found between theoretical study and simulated responses.     

Methylene blue adsorption from aqueous solutions to flexible poly(vinyl chloride) silica composites

Methylene blue (MB) adsorption studies were performed with poly(vinyl chloride)‐(dioctyl phthalate)‐silica composites, which were obtained by using plastisol‐plastigel technology. The films were flexible, having elastic modulus of 1.0–1.5 GPa. Diminishing MB concentration in the aqueous phase was followed as the adsorption process advanced by using visible spectroscopy. Contributions of the individual components of the composites to adsorption were also investigated. Although the MB adsorption capacity was extensively high for silica, it was moderate for the composite, most likely owing to the occlusion of pores of silica by plasticizer to some extent. The improvement of MB adsorption capacity of the composites as the silica ratio increased was explicitly deduced from the optical microscopy photographs. The diffusion coefficients of MB through the composites were 5 × 10^?13, 6 × 10^?13, and 3 × 10^?13 m² s^?1 with regression coefficients of 0.73, 0.89, and 0.88 for 0, 2, and 16% silica‐containing composites, respectively. Because of the slow diffusion of MB in poly(vinyl chloride)‐silica composites, using them as dynamic column adsorbent was not practical. However, these versatile plastics can be used as plastic labels, colored clothing, leather substitutes, antimicrobial medical devices, and laser printable surfaces. J. VINYL ADDIT. TECHNOL., 21:42–50, 2015. © 2014 Society of Plastics Engineers