Comparison of High Frequency Detailed Generator Models for Partial Discharge Localization

Hassan Hosseini, S.M.,Hosseini Bafghi, S.M. The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.4

This paper presents partial discharge localization in stator winding of generators using multi-conductor transmission line (MTL) and RLC ladder network models. The high-voltage (HV) winding of a 6kV/250kW generator has been modeled by MATLAB software. The simulation results of the MTL and the RLC ladder network models have been evaluated with the measurements results in the frequency domain by applying of the Pearson’s correlation coefficients. Two PD generated calibrator signals in kHz and MHz frequency range were injected into different points of generator winding and the signals simulated/measured at the both ends of the winding. For partial discharge localization in stator winding of generators is necessary to calculate the frequency spectrum of the PD current signals and then estimate the poles of the system from the calculated frequency spectrum. Finally, the location of PD can be estimated. This theory applied for the above generator and the simulation/measured results show the good correlation for PD Location for RLC ladder network and MTL models in the frequency range of kHz (10kHz<f<1MHz) and MHz (1MHz<f<5MHz) respectively.

Lipid-Lowering Effects of Concurrent Training and Green Tea Consumption in Overweight Women

Zahra Hosseini,Hadi Ghaedi,Mozhgan Ahmadi,Seyed Ali Hosseini 대한비만학회 2020 The Korean journal of obesity Vol.29 No.4

Background: Exercise conducted simultaneously with the consumption of herbal supplements is one of the suggested methods for controlling obesity and its complications. The present study sought to investigate the lipid-lowering effects of concurrent training and green tea (GT) consumption in overweight women. Methods: In this quasi-experimental study, 40 overweight women were selected and stratified into four groups: control (C), GT, concurrent training+placebo (TP), and concurrent training+GT (three tablets containing 500 mg of GT per week; T+GT) groups. Both the TP and T+GT groups performed exercise three sessions per week for 8 weeks. Fasting blood samples were collected before and 48 hours after the last training session. Results: Low-density lipoprotein cholesterol levels in the T+GT (P=0.03) and TP (P=0.001) groups were significantly decreased relative to in the GT group and were significantly decreased in the T+GT group relative to in the TP group (P=0.001). Meanwhile, high-density lipoprotein cholesterol levels in the T+GT group were significantly increased as compared with in the GT (P=0.01), TP (P=0.03), and C (P=0.04) groups. Finally, total cholesterol levels in the T+GT group were decreased significantly as compared with in the TP, GT, and C groups (P=0.001) and triglyceride levels in the T+GT, TP, and GT groups were significantly increased as compared with in the C group (P=0.001). Conclusion: Exercise performed simultaneously with GT consumption in comparison with either alone has a greater effect on improving the lipid profile in overweight women.

Enhancing performance of polyacrylonitrile membranes for pervaporation dehydration of ethanol by tailoring morphology and process parameters

Seyed Mohammad Hosseini Nejad,Amir Hossein Mostafavi,Seyed Saeid Hosseini,Haoze Zeng,Lu Shao 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.10

Development of high performance membranes for ethanol (EtOH) dehydration constitutes one of the main applications of pervaporation technology. In the present study, the properties of membranes derived from PAN were examined for this purpose. Heat treatment and variation of operational parameters were explored as viable strategies for enhancing the process performance. The characteristics of the membranes including morphology, thickness and sorption behavior were investigated in detail to identify their roles. Application of heat treatment with regards to polymer Tg resulted in membranes with distinct morphological and sorption characteristics. Increase in operational temperature was found effective for optimizing the opposing trends of permeate flux and separation factor. The maximum PSI value for the pristine PAN membrane was 5,564.0 g·m−2h−1, which occurred for operation at 50 °C. Also, application of heat treatment led to drop in flux and increase in separation factor by which PSI reached 41.3 kg·m−2h−1, which was 7.5 times than that of pristine PAN membrane. This study demonstrates successful implementation of facile strategies for tuning the characteristics and performance of membranes derived from PAN for efficient dehydration of EtOH via pervaporation process.

Generalized coupled non-Fickian/non-Fourierian diffusion- thermoelasticity analysis subjected to shock loading using analytical method

Seyed Amin Hosseini,Mohammad Hossein Abolbashari,Seyed Mahmoud Hosseini 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.60 No.3

In this article, the generalized coupled non-Fickian diffusion-thermoelasticity analysis is carried out using an analytical method. The transient behaviors of field variables, including mass concentration, temperature and displacement are studied in a strip, which is subjected to shock loading. The governing equations are derived using generalized coupled non-Fickian diffusion-thermoelasticity theory, which is based on Lord-Shulman theory of coupled thermoelasticity. The governing equations are transferred to the frequency domain using Laplace transform technique and then the field variables are obtained in analytical forms using the presented method. The field variables are eventually determined in time domain by employing the Talbot technique. The dynamic behaviors of mass concentration, temperature and displacement are studied in details. It is concluded that the presented analytical method has a high capability for simulating the wave propagation with finite speed in mass concentration field as well as for tracking thermoelastic waves. Furthermore, the obtained results are more realistic than that of others.

Mechanical Properties of Concrete by Use of Astragalus Resin

Seyed, Jamal Aldin Hosseini(세예드 자말 알딘 호세이니),Hwang, Hyeon-Jong(황현종),Jila, Raeiji(질라래이지),Fatemeh, Sadat Hosseini(파테메 사다트 호세이니) 한국콘크리트학회 2021 한국콘크리트학회 학술대회 논문집 Vol.33 No.2

본 연구에서는 이란 북부지역에서 흔히 볼 수 있는 황기수지를 가소제로 사용하여 콘크리트의 기계적 특성을 조사하였다. 황기수지는 시멘트 함량의 1 %∼3 %의 투입량을 사용하였다. 콘크리트의 슬럼프, 단위 중량 및 경화 특성(7일 및 28일 압축 강도)과 같은 신선한 콘크리트의 기계적 특성을 실험적으로 연구하였다. 시험 결과 콘크리트의 작업성이 향상되었으며, 시멘트 함량의 2% 배합시 콘크리트는 레올로지, 작업성, 압축강도가 증가하였다. This study investigated the mechanical properties of concrete by use of Astragalus resin which is frequently found in the north of Iran, as a plasticizer. The Astragalus resin was used with a dosage of 1 % to 3% of cement content. The mechanical properties of fresh concrete, such as slump, unit weight, and hardened properties of concrete (7-day and 28-day compressive strength). The test results indicated that the Astragalus resin improved the workability of fresh concrete. The concrete containing resin by 2% of cement content exhibited higher rheology, workability, and compressive strength.

Comparison of High Frequency Detailed Generator Models for Partial Discharge Localization

S. M. Hassan Hosseini,S. M. Hosseini Bafghi 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.4

This paper presents partial discharge localization in stator winding of generators using multi-conductor transmission line (MTL) and RLC ladder network models. The high-voltage (HV) winding of a 6kV/250kW generator has been modeled by MATLAB software. The simulation results of the MTL and the RLC ladder network models have been evaluated with the measurements results in the frequency domain by applying of the Pearson’s correlation coefficients. Two PD generated calibrator signals in kHz and MHz frequency range were injected into different points of generator winding and the signals simulated/measured at the both ends of the winding. For partial discharge localization in stator winding of generators is necessary to calculate the frequency spectrum of the PD current signals and then estimate the poles of the system from the calculated frequency spectrum. Finally, the location of PD can be estimated. This theory applied for the above generator and the simulation/measured results show the good correlation for PD Location for RLC ladder network and MTL models in the frequency range of kHz (10kHz<f<1MHz) and MHz (1MHz<f<5MHz) respectively.

Three dimensional dynamic response of functionally graded nanoplates under a moving load

Hosseini-Hashemi, Shahrokh,Khaniki, Hossein Bakhshi Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.66 No.2

In this paper, reaction of functionally graded (FG) thick nanoplates resting on a viscoelastic foundation to a moving nanoparticle/load is investigated. Nanoplate is assumed to be thick by using second order shear deformation theory and small-scale effects are taken into account in the framework of Eringen's nonlocal theory. Material properties are varied through the thickness using FG models by having power-law, sigmoid and exponential functions for material changes. FG nanoplate is assumed to be on a viscoelastic medium which is modeled using Kelvin-Voight viscoelastic model. Galerkin, state space and fourth-order Runge-Kutta methods are employed to solve the governing equations. A comprehensive parametric study is presetned to show the influence of different parameters on mechanical behavior of the system. It is shown that material variation in conjunction with nonlocal term have a significant effect on the dynamic deformation of nanoplate which could be used in comprehending and designing more efficient nanostructures. Moreover, it is shown that having a viscoelastic medium could play an important role in decreasing these dynamic deformations. With respect to the fresh studies on moving atoms, molecules, cells, nanocars, nanotrims and point loads on different nanosctructures using scanning tunneling microscopes (STM) and atomic force microscopes (AFM), this study could be a step forward in understanding, predicting and controlling such kind of behaviors by showing the influence of the moving path, velocity etc. on dynamic reaction of the plate.

Application of FSM-16 impregnated by TiO2 as an efficient photocatalyst for elimination of benzothiophene and dibenzothiophene, adsorptive removal of degradation products by MCM-41

Hosseini Asma,Faghihian Hossein 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.76 No.-

A novel photocatalyst was prepared by immobilization of TiO2 on the surface of FSM-16 catalyst support,and was characterized by different techniques. Optical properties of synthesized sample studied bydiffuse reflectance spectroscopy, and photoluminescence analysis indicated that after immobilization thebang gap energy of TiO2 was shifted to visible region, and electron-hole recombination was reduced. Thedegradation tests performed at various conditions under UV and visible lights showed that at optimizedconditions 91% of benzothiophene and 77% of dibenzothiophene were eliminated. Degradation productswere identified by GC–MS, and were removed by MCM-41 adsorbent. The used photocatalyst was highlyregenerable.

Development of Galerkin Finite Element Method Three-dimensional Computational Code for the Multigroup Neutron Diffusion Equation with Unstructured Tetrahedron Elements

Hosseini, Seyed Abolfazl Korean Nuclear Society 2016 Nuclear Engineering and Technology Vol.48 No.1

In the present paper, development of the three-dimensional (3D) computational code based on Galerkin finite element method (GFEM) for solving the multigroup forward/adjoint diffusion equation in both rectangular and hexagonal geometries is reported. Linear approximation of shape functions in the GFEM with unstructured tetrahedron elements is used in the calculation. Both criticality and fixed source calculations may be performed using the developed GFEM-3D computational code. An acceptable level of accuracy at a low computational cost is the main advantage of applying the unstructured tetrahedron elements. The unstructured tetrahedron elements generated with Gambit software are used in the GFEM-3D computational code through a developed interface. The forward/adjoint multiplication factor, forward/adjoint flux distribution, and power distribution in the reactor core are calculated using the power iteration method. Criticality calculations are benchmarked against the valid solution of the neutron diffusion equation for International Atomic Energy Agency (IAEA)-3D and Water-Water Energetic Reactor (VVER)-1000 reactor cores. In addition, validation of the calculations against the $P_1$ approximation of the transport theory is investigated in relation to the liquid metal fast breeder reactor benchmark problem. The neutron fixed source calculations are benchmarked through a comparison with the results obtained from similar computational codes. Finally, an analysis of the sensitivity of calculations to the number of elements is performed.

Simplified approach on modeling of embedded reinforcements in flexural concrete members

Hosseini, Seyed Muoud,Ghomian, Majid,BaniAsad, Elham,Dehestani, Mehdi Techno-Press 2021 Advances in concrete construction Vol.12 No.3

Several factors need to be considered in modeling of reinforced concrete beams. Bond-slip is one of the most important factors that play a key role in the behavior of reinforced concrete structures, under static and dynamic loads. A comparison between the results of experimental tests and numerical models show that considering a complete bond (perfect with no slip) instead of real bond-slip phenomenon, in numerical finite element models leads to higher estimations for the stiffness. In this study, the effects of the bond-slip phenomenon on the behavior of the reinforced concrete beams are considered. It is shown that the influence of bond-slip behavior between steel and concrete depends on the compressive strength of concrete, the concrete cover, stirrups and rebar diameter. Subsequently, a method is proposed to consider the effects of the interfacial behavior between concrete and rebar while a complete bond assumption remains and the rebar is introduced as embedded element in concrete. The bond-slip effect is considered by adding an equivalent strain of bond to the strain of steel rebar and then modifying the terms of the modulus of elasticity of steel. Validation model and parametric analyses are conducted to consider the effects of bond-slip properties and other parameters affecting the behavior of reinforced concrete beams.