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.

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.

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.

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.

A novel preparation of polyaniline in presence electric and magnetic fields

Hosseini, Seyed Hossein,Gohari, S. Jamal Techno-Press 2013 Advances in materials research Vol.2 No.4

We have described primary studies on conductivity and molecular weight of polyaniline separately in the electric and magnetic fields when it is used in a field effect experimental configuration. We report further studies on doped in-situ deposited polyaniline. First we have chemically synthesized polyaniline by ammonium peroxodisulfate in acidic aques and organic solutions at different times. Then we measured mass and conductivity and obtained the best time of polymerizations. In continue, we repeated these reactions separately under different electric and magnetic fields in constant time and measured mass and conductivity. The polyaniline is characterized by gel permeation chromatography (GPC), UV-Visible spectroscopy and electrical conductivity. High molecular weight polyanilines are synthesized under electric field, $M_w$ = 520000-680000 g/mol, with $M_w/M_n$ = 2-2.5. The UV-Visible spectra of polyanilines oxidized by ammonium peroxodisulfate and protonated with dodecylbenzenesulfonic acid (PANi-DBSA), in N-methylpyrolidone (NMP), show a smeared polaron peak shifted into the visible. Electrical conductivity of polyanilines has been studied by four-probe method. The conductivity of the films of emeraldine protonated by DBSA cast from NMP are higher than 500 and 25 S/cm under 10 KV/m of potential) electric field and 0.1 T magnetic field, respectively. It shows an enhanced resistance to ageing too. By the next steps, we carried chemical polymerization at the best electric and magnetic fields at different times. Finally, resulted in finding the best time and amount of the fields. The longer polymerization time and the higher magnetic field can lead to degradation of polyaniline films and decrease conductivity and molecular mass.

Prognostic significance of adjuvant radiation therapy in adenocarcinoma of the cecum

Hosseini, Sare,Bananzadeh, Ali Mohammad,Mohammadianpanah, Mohammad,Salek, Roham,Taghizadeh-Kermani, Ali The Korean Society for Radiation Oncology 2018 Radiation Oncology Journal Vol.36 No.1

Purpose: Local recurrence is a common failure pattern in adenocarcinoma of the cecum. This study aimed to investigate the potential role of adjuvant radiation therapy on oncologic outcomes of patients with adenocarcinoma of the cecum. Materials and Methods: This retrospective study was carried out at three large tertiary university hospitals. We analyzed the characteristics, prognostic factors, and survival of 162 patients with adenocarcinoma of the cecum that were treated and followed up between 2000 and 2013. All the patients had undergone a right hemicolectomy and received chemotherapy with (n = 48) or without (n = 114) adjuvant radiation therapy. Results: The subjects were 65 females and 97 males with a median age of 56 years (range, 17 to 90 years) at diagnosis. The 5-year local control (LC), disease free survival (DFS), and overall survival (OS) rates were 72.7%, 57.2%, and 62.6% respectively. In a multivariate analysis, age, tumor stage, node stage, and adjuvant radiation therapy were determined to be independent prognostic factors. Age more than 55 years (hazard ratio [HR] = 1.0; 95% confidence interval [CI], 0.06-0.32; p = 0.003), T4 stage (HR = 6.8; 95% CI, 3.07-15.36; p < 0.001), node positive disease (HR = 4.2; 95% CI, 1.94-9.13; p < 0.001), and the absence of adjuvant radiation therapy (HR = 3.0; 95% CI, 1.39-6.46; p = 0.005) had a negative influence on OS. Conclusion: Adjuvant radiation therapy significantly improves DFS and OS in patients with adenocarcinoma of the cecum.

PURE INJECTIVE REPRESENTATIONS OF QUIVERS

Hosseini, Esmaeil Korean Mathematical Society 2013 대한수학회보 Vol.50 No.2

Let R be a ring and $\mathcal{Q}$ be a quiver. In this paper we give another definition of purity in the category of quiver representations. Under such definition we prove that the class of all pure injective representations of $\mathcal{Q}$ by R-modules is preenveloping. In case $\mathcal{Q}$ is a left rooted semi-co-barren quiver and R is left Noetherian, we show that every cotorsion flat representation of $\mathcal{Q}$ is pure injective. If, furthermore, R is $n$-perfect and $\mathcal{F}$ is a flat representation $\mathcal{Q}$, then the pure injective dimension of $\mathcal{F}$ is at most $n$.

Solvent-free Synthesis of Propargylic Alcohols using ZnO as a New and Reusable Catalyst by Direct Addition of Alkynes to Aldehydes

Hosseini-Sarvari, Mona,Mardaneh, Zahra Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.12

Under solvent-free conditions, the synthesis of propargylic alcohols by direct addition of terminal alkynes to aldehydes promoted by ZnO as a novel, commercially, and cheap catalyst is described. Furthermore, the catalyst can be reused for several times without any significant loss of its catalytic activity.