Calculation of Nano-charged Particles Pulsation Frequency in Tokamak

One of the unknown problems that cause to perturbation of tokamak function is charged particles pulsation. Applying the toroidal magnetic field to the charged motive particles implicate plasma in the system. This plasma has a frequency that depends on the toroidal magnetic field. Another frequency exists in this system that is caused to the plasma self magnetism. This lateral pulsation is principal origin of perturbation in the system. In this paper, nano-charged particles pulsation is investigated and its frequency is calculated by Buckingham method. Knowing this frequency is necessary to control perturbation. The result of calculations shows that temperature increasing of the system cause to more intense perturbation.     

A Low Complexity Suboptimal Energy-Based Detection Method for SISO/MIMO Channels

In this paper, we propose an actually novel and simple method for detection of transmitted symbols in MIMO channels. This method is based on the energy level of the received signals. At the receiver, we assume the knowledge of channel state information which can be estimated by different methods, e.g. by sending pilots. So, we can determine all possible levels of energy. This computation of energy levels is done only once for the quasi-static channels. Energy of the received signals is a criterion by which we can estimate the transmitted symbols. Detection of transmitted signal is made based on the nearest energy level and the points which lie on it. In other words, we have restricted our search space to a new smaller space with different levels of energy. Simulation results confirm approximately the same performance between the maximum-likelihood detector and the proposed approach especially in high signal-to-noise ratios with a remarkable reduction in the computational complexity.     

Grading of gliomas using transfer learning on MRI images

Magnetic Resonance Materials in Physics, Biology and Medicine - Despite the critical role of Magnetic Resonance Imaging (MRI) in the diagnosis of brain tumours, there are still many pitfalls in the...     

Microfluidic behavior in melt-spun hollow and liquid core fibers

The development of thermoplastic fibers containing a liquid core is described. Internal morphology analysis confirms that the liquid-containing core is composed of a continuous cylindrical microchannel of constant diameter. Microfluidic experiments on both liquid core and reference hollow fibers were conducted by pumping distilled water through several filaments simultaneously. The observed fluid motions are satisfactorily described by the Hagen-Poiseuille law, indicating that the hollow and liquid core fibers have internal diameters of 31.6 and 14.8 µm, respectively. Flushing the liquid core fibers with a surfactant solution efficiently removes the saturated ester initially used during the melt spinning of the fiber.     

Spark plasma sintering of Al-doped ZrB2–SiC composite

This research presents the influence of Al addition on microstructure and mechanical behavior of ZrB₂–SiC ultra-high temperature ceramic matrix composite (UHTCMC) fabricated by spark plasma sintering (SPS). A 2.5?wt% Al-doped ZrB₂–20?vol% SiC UHTCMC was produced by SPS method at 1900?°C under a pressure of 40?MPa for 7?min. The microstructural and phase analysis of the composite showed that aluminum-containing compounds were formed in-situ during the SPS as a result of chemical reactions between Al and surface oxide films of the raw materials (i.e. ZrO₂ and SiO₂ on the surfaces of ZrB₂ and SiC particles, respectively). The Al dopant was completely consumed and converted to the intermetallic Al₃Zr and Al₄Si compounds as well as Al₂O₃ and Al₂SiO₅. A relative density of 99.8%, a hardness (HV5) of 21.5?GPa and a fracture toughness (indentation method) of 6.3?MPa?m^1/2 were estimated for the Al-doped ZrB₂–SiC composite. Crack bridging, branching, and deflection were identified as the main toughening mechanisms.     

Poly (lactic acid) foaming

Poly (lactic acid) or polylactide (PLA) is an aliphatic thermoplastic polyester produced from renewable resources and is compostable in the environment. Because of the massive use of foamed products of petroleum-based polymers, PLA foams have been considered as substitutes for some of these products. Specifically, because of PLA's competitive material and processing costs, and its comparable mechanical properties, PLA foams could potentially replace polystyrene (PS) foam products in a wide array of applications such as packaging, cushioning, construction, thermal and sound insulation, and plastic utensils. Due to their biocompatibility, PLA foams can also be used in such biomedical applications as scaffolding and tissue engineering. But PLA has several inherent drawbacks, which inhibit the production of low-density foams with uniform cell morphology. These drawbacks are mainly the PLA's low melt strength and its slow crystallization kinetics. During the last two decades, researchers have investigated the fundamentals of PLA/gas mixtures, PLA foaming mechanisms, and the effects of material modification on PLA's foaming behavior through various manufacturing technologies. This article reviews these investigations and compares the developments made thus far in PLA foaming.     

Morphology enhancement of TiO2/PVP composite nanofibers based on solution viscosity and processing parameters of electrospinning method

In this work, different sol solutions with various titanium tetraisopropoxide (TIP)/glacial acetic acid ratios in 2‐propanol with 5 wt % poly(vinyl pyrrolidone) (PVP) (M_w = 360,000 g/mol) were prepared and electrospun. Composition of the prepared sols and as‐spun TiO₂/PVP nanofibers were determined by Fourier transform infrared and Raman spectroscopy methods. Morphology of the electrospun TiO₂/PVP nanofibers was studied by scanning electron microscopy and transmission electron microscopy (TEM) techniques. Rheometry measurements of the sol solutions showed decrease of viscosity upon the addition of TIP to the polymer solutions with constant polymer and acid concentrations. The sol solution having the lowest viscosity (at shear rate 10 s^?1) but the highest TIP/glacial acetic acid ratio showed beaded nanofibers morphology when electrospun under 10 and 12 kV applied voltage while injection rate, needle tip to collector distance, and needle gauge were kept constant. However, smooth electrospun TiO₂/PVP composite nanofibers with the average nanofibers diameters (148 ± 79 nm) were achieved under the same condition when applied voltage increased to 15 kV. TEM micrographs of the electrospun TiO₂/PVP nanofiber showed that the TiO₂ particles with continuous structure are formed at the middle of the nanofiber and distributed along its axis. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46337.     

Applying dual-tree complex discrete wavelet transform and gamma modulating function for simulation of ground motions

The aim of this paper is to develop a stochastic-parametric model for the generation of synthetic ground motions (GMs) which are in accordance with a real GM. In the proposed model, the dual-tree complex discrete wavelet transform (DT-CDWT) is applied to real GMs to decompose them into several frequency bands. Then, the gamma modulating function (GMF) is used to simulate the wavelet coefficients of each level. Consequently, synthetic wavelet coefficients are generated using extracted model parameters and then synthetic GM is extracted by applying the inverse DT-CDWT to synthetic wavelet coefficients. This model simulates the time–frequency distribution of both wide-frequency and narrow-frequency bandwidth GMs. Besides being less time consuming, it simulates several dominant frequency peaks at any moment in the time duration of GM, because each frequency band is separately simulated by the gamma function. Moreover, the inelastic response spectra of synthetic GMs generated by the proposed model are a good estimate of target ones. Using the random sign generator in the proposed model, it is possible to generate any number of synthetic GMs in accordance with a recorded one. Because of these advantages, the proposed model is suitable for using in performance-based earthquake engineering.