Bidirectional Quasi-Cuk DC/DC Converter with Reduced Voltage Stress on Capacitor and Capability of Changing the Output Polarity

Asl, Elias Shokati,Sabahi, Mehran The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.12 No.3

In this paper, a bidirectional topology for quasi-Cuk dc/dc converter with capability of zero-voltage and zero-current-switching (ZVZCS) is proposed. The bidirectional quasi-Cuk (BQ-Cuk) converter has different voltage and current transfer ratio, reduced voltage stress on capacitor and capability of changing the output polarity in comparison with conventional bidirectional Cuk converter. In this paper, steady-state analysis of the quasi-Cuk converter with capability of ZVZCS in turn-on is presented. Then, critical inductances for transient from this operation to two new operations are calculated. Next, besides values designing of used elements, maximum and minimum value of their current and voltage are calculated. Finally, experimental results to verify the accuracy of the proposed converter in different operating modes are presented.

Histopathology of leech parasitism on Capoeta capoeta gracilis, Squalius cephalus and Carassius auratus

asl, Adel Haghighi Khiabanian,Salimi, Behnam The Korean Society of Fish Pathology 2017 한국어병학회지 Vol.30 No.2

Parasitic leeches could directly (through causing poor growth, anemia and wound in the fish) and indirectly (by predisposition of the fish to secondary bacterial and fungal infections) affects their hosts. In the present study, fishes that were attacked by leeches in natural and experimental environment were studied. Pathologic samples were obtained from damages at the site of leech bite, as well as kidney and liver of the fish. Histopathological examination revealed numerous lesions at the site of leech bite including tissue demolition, detachment at the site of leech bite in the epidermis of epithelial tissue in the skin, destructed nucleus in epithelial cells of the skin plus necrosis in the damaged skin and weak inflammatory penetration to acute necrotic damages along with piercing dermis layer. Pathologic lesions in the kidney included some changes such as proliferation by increasing glomerular cells and membrane cells in capillary vein of the kidney, blood cell necrosis in kidney with infiltration of white blood cells mainly mononuclear and less polymorphonuclear which are the symptoms of anemia due to blood feeding and sucking by leeches. There was also a chronic kidney infection probably originated from another part of body such as skin. Moreover, leeches caused hemorrhagic anemia due to blood consumption of the hosts, which led to observation of immature red blood cells. Also results showed that diseases induced by leeched in fish could be acute or chronic, which depends on size of fish, species of leech and severity of infection.

Analysis of the Linearity and Shift Invariance Characteristics of the X-Space Magnetic Particle Imaging

Asl, Hamed Jabbari,Kim, Myeong Ok,Yoon, Jungwon American Scientific Publishers 2016 Journal of nanoscience and nanotechnology Vol.16 No.8

<P>The x-space reconstruction method for magnetic particle imaging (MPI) is a fast and robust method which provides the possibility for real-time imaging of the magnetic nanoparticle tracers. One limitation of this method is the requirement to utilize the complete MPI signal. The necessary filtering action in the MPI, removes the first harmonic information which affects the linearity and shift invariance (LSI) characteristics of the image. In this paper, LSI properties of the x-space imaging, necessary for medical diagnosis applications, is analyzed. It is shown that filtering the output signal causes an image loss which depends on the trajectory of the drive field where, for a harmonic drive field, its value is constant and can be compensated in 1D imaging. The findings of this paper reveal the importance of the method of applying the driving field in multidimensional x-space in order to keep the LSI properties.</P>

Bounded‐input control of the quadrotor unmanned aerial vehicle: a vision‐based approach

Asl, Hamed Jabbari,Yoon, Jungwon Wiley-Blackwell 2017 Asian journal of control Vol.19 No.3

An Analytical Approach for Fast Recovery of the LSI Properties in Magnetic Particle Imaging

Jabbari Asl, Hamed,Yoon, Jungwon Hindawi Publishing Corporation 2016 International journal of biomedical imaging Vol.2016 No.-

<P>Linearity and shift invariance (LSI) characteristics of magnetic particle imaging (MPI) are important properties for quantitative medical diagnosis applications. The MPI image equations have been theoretically shown to exhibit LSI; however, in practice, the necessary filtering action removes the first harmonic information, which destroys the LSI characteristics. This lost information can be constant in the <I>x</I>-space reconstruction method. Available recovery algorithms, which are based on signal matching of multiple partial field of views (pFOVs), require much processing time and<I> a priori</I> information at the start of imaging. In this paper, a fast analytical recovery algorithm is proposed to restore the LSI properties of the <I>x</I>-space MPI images, representable as an image of discrete concentrations of magnetic material. The method utilizes the one-dimensional (1D) <I>x</I>-space imaging kernel and properties of the image and lost image equations. The approach does not require overlapping of pFOVs, and its complexity depends only on a small-sized system of linear equations; therefore, it can reduce the processing time. Moreover, the algorithm only needs<I> a priori</I> information which can be obtained at one imaging process. Considering different particle distributions, several simulations are conducted, and results of 1D and 2D imaging demonstrate the effectiveness of the proposed approach.</P>

Robust image-based control of the quadrotor unmanned aerial vehicle

Jabbari Asl, Hamed,Yoon, Jungwon Springer-Verlag 2016 Nonlinear dynamics Vol.85 No.3

Effects of internal stresses and intermediate phases on the coarsening of coherent precipitates: A phase-field study

M. Asle Zaeem,H. El Kadiri,M.F. Horstemeyer,M. Khafizov,Z. Utegulov 한국물리학회 2012 Current Applied Physics Vol.12 No.2

Phase stability, topology and size evolution of precipitates are important factors in determining the mechanical properties of crystalline materials. In this article, the CahneHilliard type of phase-field model was coupled to elasticity equations within a mixed-order Galerkin finite element framework to study the coarsening morphology of coherent precipitates. The effects of capillarity, particle size and fraction,compositional strain, and inhomogeneous elasticity on the kinetics and kinematics of coherent precipitates in a binary dual phase crystal admitting a third intermediate stable/meta-stable phase were investigated. The results demonstrated the ability of the model to simulate coarsening under the concomitant action of Ostwald ripening and mismatch elastic strain mechanisms. Using a phenomenological coarsening power law, coarsening rates were determined to depend on precipitate size and volume fraction, compositional strain, and strain mismatch between precipitates and the matrix. Results also showed that the necking incubation time between two neighboring precipitates depends inversely on the precipitate’s initial sizes; however, under fixed volume fraction of precipitates, any increase in the initial sizes of the precipitates mitigates the coarsening. Meanwhile, the compositional strain and the growth of the intermediate stable/meta-stable phase leads to substantial enhancements of precipitate coarsening.

Evaluation of thymolphthalein-grafted graphene oxide as an antioxidant for polypropylene

Mona Bagheripour-Asl,Reza Jahanmardi,Hasan Tahermansouri,Erfan Forghani 한국탄소학회 2018 Carbon Letters Vol.25 No.-

In the present work, capability of thymolphthalein-grafted graphene oxide, which was successfully synthesized in this study, in stabilization of polypropylene against thermal oxidation were investigated and compared with that of SONGNOX 1010, a commercially used phenolic antioxidant for the polymer. The modified graphene oxide were incorporated into polypropylene via melt mixing. State of distribution of the nanoplatelets in the polymer matrix was examined using scanning electron microscopy and was shown to be homogeneous. Measurements of oxidation onset temperature and oxidative induction time revealed that thymolphthalein-grafted graphene oxide modifies thermo-oxidative stability of the polymer in the melt state remarkably. However, the efficiency of the nanoplatelets in stabilization of polypropylene against thermal oxidation in melt state was shown to be inferior to that of SONGNOX 1010. Furthermore, oven ageing experiments followed by Fourier transform infrared spectroscopy showed that the modified graphene oxide improves thermo-oxidative stability of the polymer strongly in the solid state, so that its stabilization efficiency is comparable to that of SONGNOX 1010.

Sinterability and flexural strength of monolithic ZrB2: role of nano‑carbon black and SiC

Mostafa Shahriari Asl,Zohre Balak 한국탄소학회 2023 Carbon Letters Vol.33 No.6

In this research, synergetic and separate influence of nano-carbon black (C.Bn) and SiC on the microstructure and flexural strength of ZrB2 were investigated. So, ZrB2 and ZrB2- 30vol%-based composites containing 10 and 15 vol% C.Bn as well as ZrB2- 15 vol% SiC were fabricated via spark plasma sintering at 1850 °C for soaking time of 8 min under the applied pressure of 35 MPa. Relative density was measured by Archimedes method. Microstructural evaluation was carried out by applying the field emission electron microscopy (FESEM), and flexural strength was measured by three-point bending test. It was found the relative density improves in the presence of C.Bn and SiC especially in synergetic state so that the full densification was gained in Z30Si10C.Bn and Z30Si15C.Bn composites through their reactions with impurities at 1850 °C. In the monolithic ZrB2 system, the C.Bn addition improves the flexural strength slightly to 300 MPa and 315 MPa from 290 MPa. However, co-doped 10 vol% C.Bn with 30 vol% SiC resulted to achieve maximum flexural strength of 486 MPa in comparison with individually applying each of them (395 MPa for Z30Si and 300 MPa for Z10 C.Bn).

Artificial neural network (ANN) approach for modeling of Cr(VI) adsorption from aqueous solution by zeolite prepared from raw fly ash (ZFA)

SeyedMostafa Hosseini Asl,Reza Katal,Maral Ahmadi,Mohamad Ghiasvand,Ali Tardast 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.3

In this present work, artificial neural networks (ANN) are applied for prediction of percentage adsorption efficiency for the removal of Cr(VI) ions from aqueous solution by zeolite (ZFA) prepared from raw fly ash (RFA). The off operational parameters such as initial pH, adsorbent dosage, contact time and temperature is studied to optimize the conditions for maximum removal of Cr(VI) ions. Three equations, i.e. Morris–Weber, Lagergren, and pseudo second order have been tested to track the kinetics of removal process. The Langmuir, Freundlich, Redlich–Peterson, Temkin, and D-R are subjected to sorption data to estimate sorption capacity. Thermodynamic parameters showed that the adsorption of Cr(VI) onto ZFA was feasible, spontaneous and endothermic. Artificial neural networks are effective in modeling and simulation of highly non-liner multivariable relationships. The comparison of the removal efficiencies of Cr(VI) using ANN model and experimental results showed that ANN model can estimate the behavior of the Cr(VI) removal process under different conditions.