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Novel Brushless Wound Rotor Synchronous Machine With Zero-Sequence Third-Harmonic Field Excitation
Jawad, Ghulam,Ali, Qasim,Lipo, Thomas A.,Kwon, Byung-Il IEEE 2016 IEEE transactions on magnetics Vol.52 No.7
<P>This paper introduces a novel topology for generating a spatial third-harmonic current component to excite the rotor field winding of a wound rotor synchronous machine to achieve brushless operation. In this topology, each of the three-phase windings on the stator is connected with a switch in parallel. In particular, two antiparallel thyristors are used to switch during positive and negative half cycles. Two windings are mounted on the rotor of the machine: 1) the harmonic winding and 2) the field winding. Zero-sequence currents are generated, when the switches are closed near zero crossing for a short time interval. Consecutive operation of the switches creates an additional spatial third-harmonic current pulsating in the stator winding. The number of poles of the stator winding and the field winding is the same (four-poles in this case) to intercept the torque generation component of the air-gap flux, whereas, the number of poles of the harmonic windings is adjusted (12-poles in this case) to intercept the harmonic component of the air-gap flux and develop voltage across the harmonic windings. Harmonic voltage is rectified through a rotating rectifier to feed dc current to the field windings. Results verify the proposed topology simulated by a 2-D finite-element method.</P>
Jawad Ahmad,Rebeca Martinez-Garcia,Salem Algarni,Jesús de-Prado-Gil,Talal Alqahtani,Kashif Irshad 한국콘크리트학회 2022 International Journal of Concrete Structures and M Vol.16 No.3
Manufacturing waste has been quickly increasing over time as a result of the fast-rising population as well as the consumption of foods that are thrown away dishonestly, resulting in environmental contamination. As a result, it has been suggested that industrial waste disposal may be considerably reduced if it could be integrated into cement concrete manufacturing. The aim of this study is to analyze the properties of concrete employing waste glass (WG) as a binding material in proportions of 5%, 10%, 15%, 20%, 25%, and 30% by weight of cement. The fresh property was assessed using a slump cone test, while mechanical performance was assessed using flexural, compressive, splitting tensile, and pull-out strength after 7, 28, and 56 days. Furthermore, microstructure analysis was studied by scan electronic microscopic (SEM), Fourier-transform infrared spectroscopy (FTIR) and thermo-gravimetric analysis (TGA) test. The results reveal that the addition of discarded glass reduces the workability of concrete. Furthermore, mechanical performance was increased up to a 20% substitution of waste glass and then gradually declined. Waste glass can be employed as a micro filler or pozzolanic material without affecting the mechanical performance of concrete, according to microstructure research.
Modeling and simulation of planar SOFC to study the electrochemical properties
Jawad Hussain,Rashid Ali,Majid Niaz Akhtar,Mujtaba Hussain Jaffery,Imran Shakir,Rizwan Raza 한국물리학회 2020 Current Applied Physics Vol.20 No.5
In this paper, modeling and simulations are carried out using COMSOL Multiphysics. A three-dimensional model is developed for a planar intermediate temperature (IT) solid oxide fuel cell (SOFC). A parametric study has been carried out to analyze the performance of SOFC. Simulations reveal some promising features and enhanced performance of SOFC. It is shown that the maximum value of power (4–3.3) kW/m2 still remains higher with significant rise of temperature (600 °C–1000 °C), nearly 0.15 kW/m2 is the very small loss of power per 100 °C rise of temperature. Results have shown that the electrolytic current density is (6700–5500) A/m2 for peak value of power (4–3.3) kW/m2 with increase of temperature (600 °C–1000 °C). For model validation we have plotted a comparison of average current density.
Jawad, Laith,Sadighzadeh, Zahra,Salarpouri, Ali,Aghouzbeni, Seyed The Ichthyological Society of Korea 2013 韓國魚類學會誌 Vol.25 No.3
A malformation of the anal fin in longfin trevally, Carangoides armatus, is described and compared with normal specimens. The fish specimen is clearly shown anal fin deformity with missing of 3 spines and 6 rays. The remaining eleven anal fin rays are shorter than those in the normal specimen. The causative factors of this anomaly were discussed.
An improved co-training approach for document Sentiment classification
Jawad Khan(자와드 칸),Aftab Alam(아프타 발람),Muhammad Numan Khan(무함마드 누만 칸),Irfan Ullah(이르판 울라),Muhammad Umair(무하마드 우매르),Umair Qudus(구두스 우매르),Tariq Habib Afridi(타리크 하비브 아프리디),Sung Soo Park(박성수),Young-Koo Lee( 한국정보과학회 2020 한국정보과학회 학술발표논문집 Vol.2020 No.7
Plasmonic effects and size relation of gold-platinum alloy nanoparticles
Jawad, Muhammad,Ali, Shazia,Waseem, Amir,Rabbani, Faiz,Amin, Bilal Ahmad Zafar,Bilal, Muhammad,Shaikh, Ahson J. Techno-Press 2019 Advances in nano research Vol.7 No.3
Plasmonic effects of gold and platinum alloy nanoparticles (Au-Pt NPs) and their comparison to size was studied. Various factors including ratios of gold and platinum salt, temperature, pH and time of addition of reducing agent were studied for their effect on particle size. The size of gold and platinum alloy nanoparticles increases with increasing concentration of Pt NPs. Temperature dependent synthesis of gold and platinum alloy nanoparticles shows decrease in size at higher temperature while at lower temperature agglomeration occurs. For pH dependent synthesis of Au-Pt nanoparticles, size was found to be increased by increase in pH from 4 to 10. Increasing the time of addition of reducing agent for synthesis of pure and gold-platinum alloy nanoparticles shows gradual increase in size as well as increase in heterogeneity of nanoparticles. The size and elemental analysis of Au-Pt nanoparticles were characterized by UV-Vis spectroscopy, XRD, SEM and EDX techniques.