Input-Output Feedback Linearization of Sensorless IM Drives with Stator and Rotor Resistances Estimation

Hajian, Masood,Soltani, Jafar,Markadeh, Gholamreza Arab,Hosseinnia, Saeed The Korean Institute of Power Electronics 2009 JOURNAL OF POWER ELECTRONICS Vol.9 No.4

Direct torque control (DTC) of induction machines (IM) is a well-known strategy of these drives control which has a fast dynamic and a good tracking response. In this paper a nonlinear DTC of speed sensorless IM drives is presented which is based on input-output feedback linearization control theory. The IM model includes iron losses using a speed dependent shunt resistance which is determined through some effective experiments. A stator flux vector is estimated through a simple integrator based on stator voltage equations in the stationary frame. A novel method is introduced for DC offset compensation which is a major problem of AC machines, especially at low speeds. Rotor speed is also determined using a rotor flux sliding-mode (SM) observer which is capable of rotor flux space vector and rotor speed simultaneous estimation. In addition, stator and rotor resistances are estimated using a simple but effective recursive least squares (RLS) method combined with the so-called SM observer. The proposed control idea is experimentally implemented in real time using a FPGA board synchronized with a personal computer (PC). Simulation and experimental results are presented to show the capability and validity of the proposed control method.

Comparison of Competitive Models of Metabolic Syndrome Using Structural Equation Modeling: A Confirmatory Factor Analysis

Karimollah Hajian-Tilaki 대한당뇨병학회 2018 Diabetes and Metabolism Journal Vol.42 No.5

Background: The purpose of this study was to apply the structural equation modeling (SEM) to compare the fitness of different competing models (one, two, and three factors) of the metabolic syndrome (MetS) in Iranian adult population. Methods: Data are given on the cardiometabolic risk factors of 841 individuals with nondiabetic adults from a cross-sectional population-based study of glucose, lipids, and MetS in the north of Iran. The three conceptual hypothesized models (single factor, two correlated factors, and three correlated latent factors) were evaluated by using confirmatory factor analysis with the SEM approach. The summary statistics of correlation coefficients and the model summary fitting indexes were calculated. Results: The findings show that a single-factor model and a two-correlated factor model had a poorer summary fitting index compared with a three-correlated factor model. All fitting criteria met the conceptual hypothesized three-correlated factor model for both sexes. However, the correlation structure between the three underlying constructs designating the MetS was higher in women than in men. Conclusion: These results indicate the plausibility of the pathophysiology and etiology of MetS being multifactorial, rather than a single factor, in a nondiabetic Iranian adult population.

Input-Output Feedback Linearization of Sensorless IM Drives with Stator and Rotor Resistances Estimation

Masood Hajian,Jafar Soltani,Gholamreza Arab Markadeh,Saeed Hosseinnia 전력전자학회 2009 JOURNAL OF POWER ELECTRONICS Vol.9 No.4

Direct torque control (DTC) of induction machines (IM) is a well-known strategy of these drives control which has a fast dynamic and a good tracking response. In this paper a nonlinear DTC of speed sensorless IM drives is presented which is based on input-output feedback linearization control theory. The IM model includes iron losses using a speed dependent shunt resistance which is determined through some effective experiments. A stator flux vector is estimated through a simple integrator based on stator voltage equations in the stationary frame. A novel method is introduced for DC offset compensation which is a major problem of AC machines, especially at low speeds. Rotor speed is also determined using a rotor flux sliding-mode (SM) observer which is capable of rotor flux space vector and rotor speed simultaneous estimation. In addition, stator and rotor resistances are estimated using a simple but effective recursive least squares (RLS) method combined with the so-called SM observer. The proposed control idea is experimentally implemented in real time using a FPGA board synchronized with a personal computer (PC). Simulation and experimental results are presented to show the capability and validity of the proposed control method.

ABO Blood Groups in Oral Cancer: A First Case-Control Study in a Defined Group of Iranian Patients

Mortazavi, Hamed,Hajian, Shima,Fadavi, Elnaz,Sabour, Siamak,Baharvand, Maryam,Bakhtiari, Sedigheh Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.3

The ABO blood group has been recently proposed to influence development of oral cancer. The aim ofthis study was to evaluate the association between the type of ABO blood group and oral cancer. In a case-control study, 104 patients with oral cancer were compared with 90 blood donors without cancer as controls. Data regarding the patient demographics, blood groups, Rh status, cancer characteristics and oral habits were also compared between two subgroups of squamous and non-squamous oral cancers. For statistical analysis, Chi-square test, t-student Test and Logistic Regression were used to analyze the relationship between ABO blood groups and oral cancer. The frequency of blood group B was significantly higher in oral cancer patients than controls (32% vs 13%) (p value=0.01), but Rh factor did not show significant difference between cases and controls. According to Logistic Regression, people with blood group B and those older than 50 had 3.5 and 19.4 times elevated risk of developing oral cancer, respectively. The frequency of squamous cell cancer was also significantly higher in men and people older than 50. On the other hand, females, people under 50, and those with blood group B were at 5.6, 2.9 and 4.3 times higher risk of developing non-squamous cell oral cancer,respectively. People with blood group B are at a greater risk of developing oral cancer, and female patients under 50 years of age with blood group B have the highest risk to develop non-squamous cell oral cancer.

Maximum Torque per Ampere Control of Induction Motor Drive without Mechanical Sensor

J.Soltani,M.Hajian,G.R.Arab 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10

In this paper, the direct rotor flux field orientation control of speed sensorless induction motor (IM) is presented. In proposed control scheme, the maximum torque per ampere (MTPA) control strategy is achieved using a so-called fast flux search method. Based on this method, for a given load torque and rotor speed, the magnitude of rotor reference flux is adjusted step by step until the effective value (RMS) of stator current becomes minimized finally. In addition, using the IM fifth order model in the stationary reference frame, a nonlinear rotor flux observer is developed which is capable of motor resistances and rotor speed simultaneously estimation. Moreover, a useful method is introduced for DC offset compensation which is a major problem of AC drives especially at low speeds. Simulation and experimental results are presented to confirm the effectiveness of the proposed method.

Cytotoxic and Apoptotic Effects of Extracts of Artemisia ciniformis Krasch. & Popov ex Poljakov on K562 and HL-60 Cell Lines

Tayarani-Najaran, Zahra,Hajian, Zahra,Mojarrab, Mahdi,Emami, Seyed Ahmad Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.17

Artemisia, as one of the largest genera in the tribe Anthemideae of the Asteraceae comprises an important part of Iranian flora. While cytotoxic and apoptotic properties have already been reported for some species of the genus there is not any report on cytotoxic effects of A. ciniformis. Petroleum ether (40-60), dichloromethane, ethyl acetate, ethanol and ethanol-water (50:50) extracts of the aerial parts of A. cinformis were subjected to cytotoxic and apoptotic evaluations on two cancer human cell lines (K562 and HL-60) and on J774 normal cells. Among multiple extracts evaluated for cytotoxicity, dichloromethane ($CH_2Cl_2$) and petroleum ether (PE) extracts were shown to possess the highest anti-proliferative effects on HL-60 and K562 cells with $IC_{50}$ values of 31.3 and $25.5{\mu}g/ml$ respectively. Apoptosis induction verified by sub-G1 peaks was seen in flow cytometry histograms. Increase in the amount of Bax protein, formation of DNA fragments, and cleavage of PARP to 24 and 89kDa sub units all confirmed induction of apoptosis by A. cinformis extracts. Taken together according to the result of the present study some extracts of A. cinformis could be considered as sources for natural cytotoxic compounds and further mechanistic and phytochemical studies are recommended to fully understand the underlying mechanisms of cnacer cell death as well as identification of responsible phytochemicals.

Is there an association between platelet and blood inflammatory indices and the risk of gestational diabetes mellitus?

( Mahta Abbasi Fashami ),( Sepideh Hajian ),( Maryam Afrakhteh ),( Mehdi Khabaz Khoob ) 대한산부인과학회 2020 Obstetrics & Gynecology Science Vol.63 No.2

Objective Gestational diabetes mellitus (GDM) is the most prevalent medical complication in pregnancy. Early diagnosis of GDM can influence maternal/neonatal outcomes. To assess the association between platelet and blood inflammatory indices and the risk of GDM occurrence using the complete blood count (CBC) test. We also aimed to determine the sensitivity of each parameter for an early screening of this disorder during pregnancy. Methods This case-control study included 2 groups of 110 pregnant women with and without GDM. The women in each group were compared after the routine screening for GDM and after the CBC test at 24-28 weeks’ gestation after being matched according to the inclusion criteria. Data were analyzed using SPSS version 16 and Medcalc version 14.8.1 software. Results There were statistically significant intergroup differences in white blood cell (WBC) count, platelet count, mean platelet volume (MPV), plateletcrit (PCT), MPV to platelet ratio, platelet to lymphocyte ratio, and Rh values. The values of lymphocyte count, neutrophil count, neutrophil to lymphocyte ratio, and blood group were not significantly different between groups. The logistic regression analysis showed the predictive values of WBC, platelet, MPV, and PCT in GDM. According to the receiver operating characteristic curve for all 3 variables, the level below the PCT chart was more than that of the others. Conclusion Increasing platelet and inflammatory indices on the CBC test in the second trimester of pregnancy seemed to be associated with the probability of GDM occurrence.

Formation of Intermetallic Compounds at the Interface of the Friction Stir Weld and Diffusion Bond of Mg-AZ31/Al-5083 Joint

Mohammad Ammar Mofid,Ehsan Loryaei,Mostafa Hajian Heidary 대한용접·접합학회 2019 대한용접·접합학회지 Vol.37 No.6

Dissimilar Friction stir and Diffusion bond welds of Al alloy 5083 and Mg alloy AZ31 were produced. The maximum temperature at the advancing side of friction stir weld rose to a maximum of 435℃. This temperature was selected as the bonding temperature, for diffusion bonding of these two alloys. The diffusion bonding time was 60 min. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) were used to investigate the compositional changes across the joint region. Dissimilar FS weld, produced layers of new phases of Al12Mg17 and Al₃Mg₂ intermetallics. DB weld, produced a melted-and-solidified eutectic structure consists a hypo-eutectic structure in the middle of the joint and a two layer structure between the eutectic and the Al base. The shear strength of joint corresponding to DB welded specimen was 43.2 MPa. The tensile strength of joint corresponding to FS welded specimen was 51.3 MPa. The present study suggests that constitutional liquation resulted in the intermetallic compound formation in the weld center.

Effects of Regular Treadmill Exercise on a DNA Oxidative-Damage Marker and Total Antioxidant Capacity in Rat Hippocampal Tissue

Soleiman Mahjoub,Arezoo Ghadi,Roghayeh Pourbagher,Karimollah Hajian-Tilaki,Jila Masrour-Roudsari 대한신경과학회 2016 Journal of Clinical Neurology Vol.12 No.4

Background and Purpose Regular exercise can result in changes in the levels of oxidative stress in the hippocampus; however, little attention has been paid to physical-activity-induced neuronal protection to exposure to lead compounds. This study investigated the effects of regular treadmill exercise on a DNA oxidative-damage marker [8-hydroxy-2’-deoxyguano¬sine (8-OHdG)] and the total antioxidant capacity (TAC) of hippocampal tissue in lead-ace¬tate exposed rats. Methods This study investigated the effects of 8 weeks of regular treadmill exercise on 8-OHdG and the TAC of hippocampal tissue in lead-acetate-exposed rats. Wistar rats were randomly divided into four groups: baseline, sham (control), lead, and exercise+lead. The ex¬ercise program involved running on a treadmill with increasing intensity five times a week for 8 weeks. Animals in the lead and exercise+lead groups received lead acetate at 20 mg/kg body weight intraperitoneally three times weekly for 8 weeks. Animals in the sham group re¬ceived solvent (ethyl oleate) at 30 mg/kg body weight three times weekly for 8 weeks. TAC and 8-OHdG were measured by spectrophotometric and ELISA techniques, respectively. Data were analyzed by ANOVA and Tukey’s post-hoc test with a significance cutoff of p≤0.05. Results The level of 8-OHdG and the TAC were significantly higher and lower, respective¬ly, in the lead group than in the baseline and sham groups (p<0.01). However, the 8-OHdG level and TAC value in hippocampal tissue were significantly decreased and increased, re-spectively, in the exercise+lead group relative to the lead group (p<0.05). Conclusions The TAC of hippocampal tissue may be directly associated with neural protec¬tion mechanisms of exercise following lead acetate injection, and the beneficial effects of regular exercise in preventing hippocampal neuronal damage could be due to decreased hippocampal oxidative stress such as reflected by a lower 8-OHdG level and increased TAC.

Deformation Mechanisms and Evolution of Second Phase Particles of Mg–Y–Nd–Gd–Zr Alloy During Plane Strain Compression

S. M. Fatemi,Y. Moradipour,M. Hajian 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.11

Deformation behavior of a rolled Mg–Y–Nd–Gd magnesium alloy was studied at a temperature range of 240–480 °C underplane strain compression. Two types of samples including different loading-constraining configurations were employed tostudy anisotropy in deformation response. The result showed that plane strain deformation mode extends the temperaturerange for predominance of twinning up to 480 °C. However, yield anisotropy was diminished by increasing temperatureto 480 °C. Moreover, plane strain deformation mode caused the development of dynamic recrystallization to be postponedto high strains. Deformation behavior of the two sample types were explained by calculation of Schmid factor and textureanalysis. Fine dynamically recrystallized grains were traced to form at 420 and 480 °C. Relying on EBSD analysis, the developmentof new grains was explained using continuous dynamic recrystallization mechanism, where pyramidal and prismaticpoles of new grains were rotated relative to their parent grain. The dynamic evolution of metastable β′ and β″ phases was alsoobserved at high temperatures, the fraction of which was remarkably increased with increasing temperature to 420 and 480 °C.