Efficiency Map of a Switched Reluctance Motor Using Finite Element Method in Vehicular Applications

Hossein Mokhtari,Ehsan Tara 전력전자학회 2007 ICPE(ISPE)논문집 Vol.- No.-

Switched Reluctance Motors (SRMs), which are simple and reliable motors, have attracted interest for electric vehicle propulsion systems. It is shown that an SRM offers a good performance at high acceleration and low speed driving conditions. Efficiency map of an electric motor is a very important characteristic specially when the motor is to be used in a wide range of speed and load variations, which is the case in electric propulsion systems. In this research, the efficiency map of an SRM is derived using a combination of the Finite Element Method (FEM) and a mathematical model. This efficiency map has been used for different driving cycles to test the SRM performance as a vehicle propulsion motor.

Assessment of Soil Chemical Properties (EC, SAR, pH) in Downstrems of a Qanat and Well (case Study: Meibod)

Mohammad Hossein Mokhtari,Mohammad Zare Ernani,Mohammad Ali Hakim Zadeh,Safoora Kargar Shoruki 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Biomechanical changes of the common carotid artery and internal jugular vein in patients with multiple sclerosis

Kimiya Rastegari,Mokhtari-Dizaji Manijhe,Mohammad Hossein Harirchian,Hassan Hashemi,Niloofar Ayoobi Yazdi,Hazhir Saberi 대한초음파의학회 2023 ULTRASONOGRAPHY Vol.42 No.1

Purpose: Investigations of the hemodynamic changes of the venous system in patients with multiple sclerosis (MS) have shown contradictory results. Herein, the biomechanical parameters of the internal jugular vein (IJV) and common carotid artery (CCA) of MS patients were extracted and compared to healthy individuals. Methods: B-mode and Doppler sequential ultrasound images of 64 IJVs and CCAs of women including 22 healthy individuals, 22 relapsing-remitting multiple sclerosis (RRMS) patients, and 20 primary-progressive multiple sclerosis (PPMS) patients were recorded and processed. The biomechanical parameters of the IJV and the CCA walls during three cardiac cycles were calculated. Results: The IJV maximum and minimum pressures were higher in the MS patients than in the healthy subjects, by 31% and 19% in RRMS patients and 39% and 24% in PPMS patients. The venous wall thicknesses in RRMS and PPMS patients were 51% and 60% higher than in healthy subjects, respectively. IJV distensibility in RRMS and PPMS patients was 70% and 75% lower, and compliance was 40% and 59% lower than in healthy subjects. The maximum intima-media thicknesses of the CCAs were 38% and 24%, and the minimum intima-media thicknesses were 27% and 23% higher in RRMS and PPMS patients than in healthy individuals, respectively. The shear modulus of CCA walls in RRMS and PPMS patients was 17% and 31%, and the radial elastic moduli were 47% and 9% higher than in healthy individuals. Conclusion: Some physical and biomechanical parameters of the CCA and IJV showed significant differences between MS patients and healthy individuals.

Diabesity Associates with Poor COVID-19 Outcomes among Hospitalized Patients

Zeinab Nikniaz,Mohammad Hossein Somi,Masood Faghih Dinevari,Ali Taghizadieh,Leila Mokhtari 대한비만학회 2021 The Korean journal of obesity Vol.30 No.2

Background: Although numerous studies have investigated obesity’s negative effect on coronavirus disease 2019 (COVID-19) outcomes, only a limited number focused on this association in diabetic patients. In this study, we analyzed the association between obesity and COVID-19 outcome (death, intensive care unit [ICU] admission, mechanical ventilation needs, quick Sequential Organ Failure Assessment [qSOFA] score, and confusion, urea, respiratory rate, blood pressure [CURB-65] scores) for hospitalized diabetic patients. Methods: In this prospective hospital-based registry of patients with COVID-19 in East Azerbaijan, Iran, 368 consecutive diabetic patients with COVID-19 were followed from admission until discharge or death. Self-reported weight and height were used to calculate body mass index (kg/m2) upon admission. Our primary endpoint was analyzing obesity and COVID-19 mortality association. Assessing the associations among obesity and disease severity, ICU admission, and mechanical ventilation was our secondary endpoint. Results: We analyzed data from 317 patients and found no significant difference between obese and non-obese patients regarding frequency of death, invasive mechanical ventilation, ICU admission, CURB-65, or qSOFA scores (P>0.05). After adjusting for confounding factors, obese diabetic COVID-19 patients were 2.72 times more likely to die than non-obese patients. Moreover, ventilator dependence (adjusted odds ratio [aOR], 1.87; 95% confidence interval [CI], 1.03–4.76) and ICU admission (aOR, 2.41; 95% CI, 1.11–5.68) odds were significantly higher for obese patients than non-obese patients. Conclusion: The results of the present study indicated that obesity worsens health outcomes for diabetic COVID-19 patients.

Evaluation of the effect of blood contamination on the compressive strength of MTA modified with hydration accelerators

Oloomi, Kaveh,Saberi, Eshaghali,Mokhtari, Hadi,Mokhtari Zonouzi, Hamid Reza,Nosrat, Ali,Nekoofar, Mohammad Hossein,Dummer, Paul Michael Howell The Korean Academy of Conservative Dentistry 2013 Restorative Dentistry & Endodontics Vol.38 No.3

Objectives: This study was performed to evaluate the effect of blood contamination on the compressive strength (CS) of Root MTA (RMTA) modified with Calcium chloride ($CaCl_2$) and Disodium hydrogen phosphate ($Na_2HPO_4$) as setting accelerators over time. Materials and Methods: A total of 110 cylindrical specimens of RMTA were divided into 6 experimental groups as follows: Group1, RMTA; Group 2, RMTA modified with $CaCl_2$ (RMTA-C); Group 3, RMTA modified with $Na_2HPO_4$ (RMTA-N); Group 4, RMTA contaminated with blood; Group 5, RMTA-C contaminated with blood; Group 6, RMTA-N contaminated with blood. The CS of specimens in all groups was evaluated after 3 hr, 24 hr, and 1 wk. In the modified groups (groups 2, 3, 5, and 6) the CS of five specimens per group was also evaluated after 1 hr. Results: Blood contamination significantly reduced the CS of all materials at all time intervals (p < 0.05). After 3 hr, the CS of specimens in the RMTA groups (with and without blood contamination) was significantly lower than those in the RMTA-C and RMTA-N groups (p < 0.05). The CS values were not significantly different at the other time intervals. In all groups, the CS of specimens significantly increased over time (p < 0.05). Conclusions: Blood contamination decreased the CS of both original and accelerated RMTA.

Modeling of mechanical properties of roller compacted concrete containing RHA using ANFIS

Ebrahim Khalilzadeh Vahidi,Maryam Mokhtari Malekabadi,Abbas Rezaei,Mohammad Mahdi Roshani,Gholam Hossein Roshani 사단법인 한국계산역학회 2017 Computers and Concrete, An International Journal Vol.19 No.4

In recent years, the use of supplementary cementing materials, especially in addition to concrete, has been the subject of many researches. Rice husk ash (RHA) is one of these materials that in this research, is added to the roller compacted concrete as one of the pozzolanic materials. This paper evaluates how different contents of RHA added to the roller compacted concrete pavement specimens, can influence on the strength and permeability. The results are compared to the control samples and determined optimal level of RHA replacement. As it was expected, RHA as supplementary cementitious materials, improved mechanical properties of roller compacted concrete pavement (RCCP). Also, the application of adaptive neuro-fuzzy inference system (ANFIS) in predicting the permeability and compressive strength is investigated. The obtained results shows that the predicted value by this model is in good agreement with the experimental, which shows the proposed ANFIS model is a useful, reliable, fast and cheap tool to predict the permeability and compressive strength. A mean relative error percentage (MRE %) less than 1.1% is obtained for the proposed ANFIS model. Also, the test results and performed modeling show that the optimal value for obtaining the maximum compressive strength and minimum permeability is offered by substituting 9% and 18% of the cement by RHA, respectively.

Power Quality Impacts of an Electric Arc Furnace and Its Compensation

Esfandiari Ahmad,Parniani Mostafa,Mokhtari Hossein The Korean Institute of Electrical Engineers 2006 Journal of Electrical Engineering & Technology Vol.1 No.2

This paper presents a new compensating system, which consists of a shunt active filter and passive components for mitigating voltage and current disturbances arising from an Electric Arc Furnace (EAF). A novel control strategy is presented for the shunt active filter. An extended method based on instantaneous power theory in a rotating reference frame is developed for extraction of compensating signals. Since voltages at the point of common coupling contain low frequency interharmonics, conventional methods cannot be used for dc voltage regulation. Therefore, a new method is introduced for this purpose. The passive components limit the fast variations of load currents and mitigate voltage notching at the Point of Common Coupling (PCC). A three-phase electric arc furnace model is used to show power quality improvement through reactive power and harmonic compensation by a shunt active filter using the proposed control method. The system performance is investigated by simulation, which shows improvement in power quality indices such as flicker severity index.

Power Quality Impacts of an Electric Arc Furnace and Its Compensation

Ahmad Esfandiari,Mostafa Parniani,Hossein Mokhtari 대한전기학회 2006 Journal of Electrical Engineering & Technology Vol.1 No.2

This paper presents a new compensating system, which consists of a shunt active filter and passive components for mitigating voltage and current disturbances arising from an Electric Arc Furnace (EAF). A novel control strategy is presented for the shunt active filter. An extended method based on instantaneous power theory in a rotating reference frame is developed for extraction of compensating signals. Since voltages at the point of common coupling contain low frequency interharmonics, conventional methods cannot be used for de voltage regulation. Therefore, a new method is introduced for this purpose. The passive components limit the fast variations of load currents and mitigate voltage notching at the Point of Common Coupling (PCC). A three-phase electric arc furnace model is used to show power quality improvement through reactive power and harmonic compensation by a shunt active filter using the proposed control method. The system performance is investigated by simulation, which shows improvement in power quality indices such as flicker severity index.

Power Quality Improvement of an Electric Arc Furnace Using a New Universal Compensating System

Ahmad Esfandiari,Mostafa Parniani,Hossein Mokhtari,Ali Yazdian-Varjani 전력전자학회 2006 JOURNAL OF POWER ELECTRONICS Vol.6 No.3

This paper presents a new compensating system, consisting of series and shunt active filters, for mitigating voltage and current disturbances. The shunt filter is used to compensate for unbalanced and distorted load currents. The series filter comprises two inverters, used to suppress voltage disturbances and handle source currents independently. This configuration is devised to reduce the overall cost of active compensators by using low-frequency high-current switches for the latter inverter. The filters are controlled separately using a novel control strategy. Since voltages at the point of common coupling contain interharmonics, conventional methods cannot be used for extracting voltage references. Therefore, voltage references are obtained from generated sinusoidal waveforms by a phase-locked loop. Current references are detected based on rotating frame vector mapping. Simulation results are presented to verify the system.

Evaluation of the effect of blood contamination on the compressive strength of MTA modified with hydration accelerators

Kaveh Oloomi,Eshaghali Saberi,Hadi Mokhtari,Hamid Reza Mokhtari Zonouzi,Ali Nosrat,Mohammad Hossein Nekoofar,Paul Michael Howell Dummer 大韓齒科保存學會 2013 Restorative Dentistry & Endodontics Vol.38 No.3

Objectives: This study was performed to evaluate the effect of blood contamination on the compressive strength (CS) of Root MTA (RMTA) modified with Calcium chloride (CaCl2) and Disodium hydrogen phosphate (Na2HPO4) as setting accelerators over time. Materials and Methods: A total of 110 cylindrical specimens of RMTA were divided into 6 experimental groups as follows: Group1, RMTA, Group 2, RMTA modified with CaCl2 (RMTA-C), Group 3, RMTA modified with Na2HPO4 (RMTA-N), Group 4, RMTA contaminated with blood, Group 5, RMTA-C contaminated with blood, Group 6, RMTA-N contaminated with blood. The CS of specimens in all groups was evaluated after 3hr, 24 hr, and 1 wk. In the modified groups (groups 2, 3, 5, and 6) the CS of five specimens per group was also evaluated after 1 hr. Results: Blood contamination significantly reduced the CS of all materials at all time intervals (p < 0.05). After 3hr, the CS of specimens in the RMTA groups (with and without blood contamination)was significantly lower than those in the RMTA-C and RMTA-N groups (p < 0.05). The CS values were not significantly different at the other time intervals. In all groups,the CS of specimens significantly increased over time (p < 0.05). Conclusions: Blood contamination decreased the CS of both original and accelerated RMTA.