Multipole Moments Based Study on Determination of Toroidal Plasma Equilibrium Position and Shift

The multipole moments based technique studied for the determination of toroidal plasma column shift. First, we presented analytical details for using this technique. Then, principle of two different models based on this technique for design and fabrication of a modified Rogowski coil (MRC) and Saddle Sine coil (SSC) will be presented. Because of continuous measurements of magnetic field distribution around the toroidal plasma using the MRC and SSC, this technique is the good method for the determination of toroidal plasma column shift.     

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.     

Bacteremia caused by CDC group IV c-2 in a patient with acute leukemia

Human infection due to CDC group IV c-2, a gram negative bacillous, are rare. We describe a case of nosocomial bacteremia caused by this organism in a neutropenic patient with acute lymphoblastic leukemia and include a literature review of CDC group IV c-2 infection in patients with hematologic malignancies.     

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.     

Microstructures and mechanical properties of Er modified AA7075 alloy

The effect of erbium and homogenization on microstructures and mechanical properties of AA7075 alloy were investigated using optical microscope (LIMI), scanning electronic microscope (SEM) equipped with energy dispersive X-ray detection (EDS) and mechanical testing. It was found that during solidification most of the elements Er and Cu segregated at the grain boundaries in the form of Al₃ErCu or Al₈Cu₄Er and a very small part of Er dissolved in the FCC-Al matrix. The latter is not completely reclaimable for heterogeneous nucleation and refine grain FCC-Al matrix in its as-cast state. Er and Cu- containing phases fragmented into fine particles after extrusion and these led to a slight increase in grain boundary strengthening. The process of homogenizing, extruding and aging the Er containing alloys considerably improved the strength due to precipitation. The analysis of the extruded sample showed that the addition of Er can slightly retard the recrystallizing behavior of AA7075 alloy.     

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.