Iran University of Science and Technology

About: Iran University of Science and Technology is a education organization based out in Tehran, Iran. It is known for research contribution in the topics: Nonlinear system & Finite element method. The organization has 12917 authors who have published 24965 publications receiving 372013 citations. The organization is also known as: Governmental Technical Institute & Advanced Art College.

Novel Wideband Planar Fractal Monopole Antenna

Abstract: A planar monopole antenna using the Penta-Gasket-Koch (PGK) is introduced. The design achieves a good input impedance match and linear phase of S11 throughout the passband (1.5-20 GHz and - 5 dB criterion for impedance bandwidth). But some occasional slight mismatch and small phase distortion occurs at low frequencies. Four different experimental results are shown and the measured gain is generally >4 dBi. For better insight, The S11 performance and input impedance of the proposed antenna are compared with those of the conventional PGK monopole antenna. For analyzing the time-domain characteristics of the antenna, the proposed antenna is assumed to be excited by the three wideband signals corresponding to 1.5-3, 6.0-12, and 13.5-20 GHz which means this antenna can be used as multiband antenna in time domain applications. However, each band consists of wide range of frequency. These bands are selected to examine the time domain response of proposed antennas. For insurability the proposed antenna can be used in pulse communications systems, the correlation between the time-domain transmitting antenna input signal and the receiving antenna output signal is calculated. This antenna is suitable for applications in ICMS, DECT, UMTS, Bluetooth, and WLAN systems. Because of linear phase and good impedance match, with some further optimization and manufacturing aspect, this antenna can serve in UWB applications.

Investigation of the Energy Regeneration of Active Suspension System in Hybrid Electric Vehicles

Abstract: This paper investigates the idea of the energy regeneration of active suspension (AS) system in hybrid electric vehicles (HEVs). For this purpose, extensive simulation and control methods are utilized to develop a simultaneous simulation in which both HEV powertrain and AS systems are simulated in a unified medium. In addition, a hybrid energy storage system (ESS) comprising electrochemical batteries and ultracapacitors (UCs) is proposed for this application. Simulation results reveal that the regeneration of the AS energy results in an improved fuel economy. Moreover, by using the hybrid ESS, AS load fluctuations are transferred from the batteries to the UCs, which, in turn, will improve the efficiency of the batteries and increase their life.

Mesoporous halloysite nanotubes modified by CuFe 2 O 4 spinel ferrite nanoparticles and study of its application as a novel and efficient heterogeneous catalyst in the synthesis of pyrazolopyridine derivatives.

Abstract: In this study, mesoporous halloysite nanotubes (HNTs) were modified by CuFe2O4 nanoparticles for the first time. The morphology, porosity and chemistry of the CuFe2O4@HNTs nanocomposite were fully characterized by Fourier transform infrared (FT-IR) spectroscopy, field-emission scanning electron microscopy (FE-SEM) image, transmission electron microscope (TEM) images, energy-dispersive X-ray (EDX), X-ray diffraction (XRD) pattern, Brunauer-Emmett-Teller (BET) adsorption-desorption isotherm, thermogravimetric (TG) and vibrating sample magnetometer (VSM) curve analyses. The results confirmed that CuFe2O4 with tetragonal structure, uniform distribution, and less agglomeration was located at HNTs. CuFe2O4@HNTs nanocomposite special features were high thermal stability, crystalline structure, and respectable magnetic property. SEM and TEM results showed the nanotube structure and confirmed the stability of basic tube in the synthetic process. Also, inner diameters of tubes were increased in calcination temperature at 500 °C. A good magnetic property of CuFe2O4@HNTs led to use it as a heterogeneous catalyst in the synthesis of pyrazolopyridine derivatives. High efficiency, green media, mild reaction conditions and easily recovery of the nanocatalyst are some advantages of this protocol.