Nanocomposite materials based on isosorbide methacrylate/Cloisite 20A

This paper reports experiments on grafting of a new polymerizable monomer onto organophilic montmorillonite. The monomer, 5‐methacryloyloxy‐1,4:36‐D ‐anhydrosorbitol (MAS), was synthesized by reacting methacryloyl chloride and isosorbide in the presence of Et₃N as base. Then, Cloisite 20A was reacted with vinyltrichlorosilane to replace the edge hydroxyl groups of the clay with a vinyl moiety. Because the reaction liberates HCl, it was performed in the presence of sodium hydrogen carbonate to prevent the exchange of quaternary alkylammonium cations with H⁺ ions. Only the silanol groups on the edge of the clay react with vinyltrichlorosilane. After the reaction, the product maintained the same basal spacing as the precursor. The radical polymerization of the product with MAS as a vinyl monomer led to chemical grafting of the polymer onto the montmorillonite surface. The homopolymer formed during polymerization was separated from the grafted organoclay by Soxhlet extraction. Chemical grafting of the polymer onto Cloisite 20A was confirmed using infrared spectroscopy. The prepared nanocomposite materials and the grafted nanoparticles were studied using X‐ray diffraction and scanning and transmission electron microscopy. Exfoliated nanocomposite was obtained for 1 wt% clay loadings. The nanocomposites were studied using thermogravimetric and dynamic mechanical analyses. Improved thermal properties were observed for nanocomposites with 1–5 wt% clay content. © 2012 Society of Chemical Industry     

多壁碳管/二氧化钛改性棉织物及其自清洁和抗紫外性能（英文）

以丁二酸为交联剂,采用纳米TiO2和多壁碳管对棉织物进行改性。通过暴露于紫外和阳光照射,分析Direct Green6浓度的减少来评价改性织物的光催化自洁性能。探讨样品的紫外吸收、耐磨性与扩张强度。结果表明,在紫外和阳光照射下,经纳米TiO2和多壁碳管处理后的棉织物能有效提高Direct Green 6的光降解效率。改性织物的耐麿性和抗紫外性能提高,抗张强度略降低。Direct Green 6光降解效率的提高归因于电子空穴对重组的减少及由TiO2和多壁碳管产生协同作用而使吸收光的增加。     

Microfibers nanocomposite based on polyacrylonitrile fibers/bismuth oxide nanoparticles as X-ray shielding material

The main focus of the current study was to fabricate fibrous nanocomposite based on polyacrylonitrile (PAN) fibers containing Bi₂O₃ NPs as the X-ray shielding material. Bi₂O₃ NPs were synthesized based on the solid dispersion evaporation method and dispersed into PAN polymer solution with different weight concentrations. The electrospinning technique was used to fabricate nanocomposite. The morphology, surface functional group, wettability, elemental analysis, and X-ray shielding efficacy of the fabricated nanocomposite were thoroughly evaluated. The dimeter of the fibrous nanocomposites containing 10, 20, and 30 wt% Bi₂O₃ NPs were 1.33 ± 0.08, 1.01 ± 0.11, and 1.69 ± 0.32 μm, respectively. EDX elemental analysis showed that NPs were uniformly distributed into/onto the fibers. The X-ray shielding studies showed that the prepared nanocomposites effectively attenuate the intensity of the X-ray. The entrance surface dose for the negative control was 24.10 ± 1.71 mSv and the application of the nanocomposites significantly reduced the entrance surface dose. The results showed NPs concentration-dependent CT number shift as the indication of X-ray protection and the highest value was obtained by 30 wt% NPs. The obtained results implied that the fabricated nanocomposites effectively attenuate the radiation and they could be applied as the X-ray shielding materials.     

Measurement of Plasma Poloidal Beta in Presence of Resonant Helical Field in IR-T1 Tokamak

Precise measurements of poloidal beta and internal inductance are essential for tokamak plasma experiments. In this paper we present an experimental investigation of effects of Resonant Helical Field (RHF) on the poloidal beta in IR-T1 tokamak. For this purpose, a diamagnetic loop with its compensation coil were constructed and installed on outer surface of the IR-T1 tokamak, and then poloidal beta measured. In order to investigate the effects of RHF on the poloidal beta, we measured it with and without introducing of different modes of the RHF (L = 2, L = 3, L = 2 & 3). Experimental results discussed.     

Ionic liquids in supercritical methanol greatly enhance transesterification reaction for high‐yield biodiesel production

Biodiesel production is one of the most promising future alternatives to replacing fossil fuels. This work studies the use of ionic liquids (ILs) as potential catalysts in supercritical methanol for biodiesel production from non‐edible oil. The transesterification reaction of karanja oil was investigated in supercritical methanol in the presence of two respective ILs, [BMIM⁺][ ] and [Chol⁺][H₂ ]. The reaction was performed in a one‐step batch process at several temperatures and percentages by weight of catalyst (w/w_oil). The results obtained show that the IL [Chol⁺][H₂ ] allows a high yield of fatty acid methyl esters to be achieved in a short reaction time (above 95% in 45 min). A catalytic mechanism is also proposed for the IL that offered significant catalytic activity. This work investigates the effects of the use of ionic liquids as potential catalysts in supercritical methanol for the transesterification reaction of non‐edible oil. The reported reaction times to obtain biodiesel yields above 90% through the transesterification reaction of karanja oil range between 90 min and 8 h. ILs as catalysts in supercritical methanol drastically reduce reaction time (45 min) to obtain high fatty acid methyl ester yield (95.6%). © 2016 American Institute of Chemical Engineers AIChE J, 62: 3842–3846, 2016     

Plasma Horizontal Displacement Measurement Using Flux Loops in IR-T1 Tokamak

In this paper we presented poloidal flux loops technique for measurement of plasma horizontal displacement in the IR-T1 tokamak. In this technique, two poloidal flux loops were designed and installed on outer surface of the IR-T1 tokamak chamber, and then the plasma displacement was obtained from them. To compare the result obtained using this method, analytical solution is also experimented on the IR-T1. Results of the two methods are in good agreement with each other.     

A broadband out‐of‐phase gysel power divider based on a dual‐band circuit with a single fixed isolation resistor

Based on the double‐sided parallel‐strip lines with an inserted conductor as a virtual ground, a high power divider with dual‐band/broadband response and frequency‐independent 180° phase difference between the output ports is implemented in this paper. The circuit topology employs a single commercially available external isolation resistor as well as moderate line impedances (15–100 ohm), making it suitable for high‐power applications. Precise closed‐form design equations on the basis of even‐ and odd‐mode analysis are derived. In addition to the wide range of frequency band ratios from 1 to 2.65, broadband response is also obtained by selecting the proper value of frequency band ratios. To substantiate the design equations and theory, a circuit with 2:1 frequency ratio and 84.5% bandwidth referring to 16 dB isolation and 12 dB return loss values is developed. To the authors' knowledge, this is the widest bandwidth reported for out‐of‐phase high power dividers. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2016.     

Effects of Resonant Helical Field (RHF) on Equilibrium Properties of IR-T1 Tokamak Plasma

In this paper we present an experimental study of effects of Resonant Helical Field (RHF) on Shafranov parameter and Shafranov shift in IR-T1 tokamak. For this purpose a four magnetic pickup coils were designed, constructed, and installed on outer surface of the IR-T1 tokamak chamber, and then the Shafranov parameter and Shafranov shift obtained. On the other hand, the external RHF applied on tokamak plasma and its effects on results measured. Experimental results of measurements with and without RHF (L = 2, L = 3, L = 2 & 3) show that the addition of a relatively small amount of RHF especially L = 3 mode could be effective for improving the quality of tokamak plasma discharge by flatting the plasma current and reducing the Shafranov parameter and Shafranov shift.     

A novel technique for the measurement of plasma displacement in IR-T1 tokamak

In this paper we present a novel technique based on poloidal magnetic flux for determination of plasma displacement in IR-T1 tokamak. This instrument consists of a two semicircle wires which installed toroidally on inner and outer sides of tokamak chamber and connected with each other. In order to receive the poloidal flux on Last Closed Flux Surface (LCFS); this instrument installed on polar coordinate so as projection of it on midplane lie on LCFS. Really, this instrument receives the difference between poloidal flux on inner and outer sides of LCFS, which we needed in calculating of the Shafranov shift. Main benefits of our proposed instrument are that it is a simple, solid, and also its output is directly related to the Shafranov shift. Based on this technique we determined the plasma position and to compare the result obtained using this method, multipole moments method is also experimented on IR-T1. Results of the two techniques are in good agreement with each other.