Analysis and Application of a Hybrid Motor Structure Convenient to Modify the Magnet and Reluctance Torques on the Rotor

Esra Kandemir Beser,Sabri Camur,Birol Arifoglu,Ersoy Beser 대한전기학회 2012 Journal of Electrical Engineering & Technology Vol.7 No.3

This paper presents a hybrid motor prototype convenient to modify the magnet and reluctance torques. The rotor of the prototype consists of magnet and reluctance parts, so the generated torque includes both magnet and reluctance torques. A considerable feature of the motor is that the ratio of the magnet and reluctance parts can be modified on the rotor and the rotor hybridization ratio can be varied. Another important point is the mechanical angle between the parts changed by means of the suitable construction of the parts on the rotor shaft. Finite element (FE) analysis was carried out for the proposed motor and static torque measurements were realized. The FE results were compared with the experimental results. Average torque and maximum torque values were obtained and three dimensional 3-D graphs were formed by using the experimental data. It is possible to make different combinations by changing the parts and the angle between the parts due to the proposed motor. So the magnet and reluctance torques are modified and different combinations give different torque behavior.

The Effect of Secondary Intraocular Lens Implantation Time on Visual Prognosis in Aphakia Cases after Open Globe Injury

Nilay Kandemir Besek,Senay Asik Nacaroglu,Mehmet Onur Er,Ahmet Kirgiz,Fevziye Ondes Yilmaz,Burç,in Kepez Yildiz,Mevlut Celal Ocal 대한안과학회 2021 Korean Journal of Ophthalmology Vol.35 No.5

Purpose: We investigated the effect of the time of secondary intraocular lens (IOL) implantation on final visual acuity and other causes affecting visual prognosis in cases left aphakic after open globe injury. Methods: The study included 62 eyes of 62 patients left aphakic after the repair of open globe injury between 2012 and 2019. Demographic characteristics, trauma zone, ocular trauma score, type of injury, time of secondary IOL implantation, final best-corrected visual acuity (BCVA), and complications were recorded for each patient. Results: The mean follow-up time of 62 patients was 25.05 ± 12.59 months. The preoperative BCVA was found to be 2.40 ± 0.86 logarithm of the minimum angle of resolution (logMAR), while the postoperative final BCVA was found to be 0.53 ± 0.70 logMAR (p < 0.01). The mean interval timing of secondary sulcus foldable IOL implantation was determined to be 3.79 ± 4.04 months. No correlation was observed between secondary IOL implantation time and final BCVA (r = 0.140, p = 0.319). Furthermore, when only pediatric patients were taken, an excellent positive correlation was found between the secondary IOL implantation time and final BCVA logMAR (r = 0.895, p < 0.01). Multiple linear regression on final BCVA with age, revealed a significant model explaining 48.0% of the variability with younger age and better final BCVA with as significant coefficients (p= 0.007). Conclusions: Although time interval between primary repair and secondary IOL implantation to correct aphakia does not effect final BCVA in adult patients, earlier surgery should be considered for amblyopia management in pediatric patients.

Comparison of Two Rotor Configurations by Changing the Amount of Magnet and Reluctance Components

Esra Kandemir Beser,Sabri Camur,Birol Arifoglu,Ersoy Beser 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.1

In this paper, two rotor configurations including different amount of magnet and reluctance parts are presented. The rotors are constituted by means of a flexible hybrid motor structure. Considerable features of the hybrid structure are that the combination of the magnet and reluctance parts can be suitably modified and the mechanical angle (β) between the parts can also be varied. Two hybrid rotor configurations have been considered in this study. First, finite element (FE) simulations were carried out and the torque behaviors of the motors were predicted. The average torque (Tavg) and maximum torque (Tmax) curves were obtained from FE simulations in order to find suitable β. Mathematical model of the motors was formed in terms of a,b,c variables considering the amount of the magnet and reluctance parts on the rotor and simulations were performed. Rotor prototypes, motor drive and drive method were introduced. Torque profiles of the motors were obtained by static torque measurement and loaded tests were also realized. Thus, simulation results were verified by experimental study. There is a good match between predictions and measurements. The proposed motors are operated with electrical 120° mode as a brushless DC motor (BLDC) and torque versus speed characteristics show a compound DC motor characteristic. The motors can be named as brushless DC compound motors.

Comparison of Two Rotor Configurations by Changing the Amount of Magnet and Reluctance Components

Beser, Esra Kandemir,Camur, Sabri,Arifoglu, Birol,Beser, Ersoy The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.1

In this paper, two rotor configurations including different amount of magnet and reluctance parts are presented. The rotors are constituted by means of a flexible hybrid motor structure. Considerable features of the hybrid structure are that the combination of the magnet and reluctance parts can be suitably modified and the mechanical angle (${\beta}$) between the parts can also be varied. Two hybrid rotor configurations have been considered in this study. First, finite element (FE) simulations were carried out and the torque behaviors of the motors were predicted. The average torque ($T_{avg}$) and maximum torque ($T_{max}$) curves were obtained from FE simulations in order to find suitable ${\beta}$. Mathematical model of the motors was formed in terms of a,b,c variables considering the amount of the magnet and reluctance parts on the rotor and simulations were performed. Rotor prototypes, motor drive and drive method were introduced. Torque profiles of the motors were obtained by static torque measurement and loaded tests were also realized. Thus, simulation results were verified by experimental study. There is a good match between predictions and measurements. The proposed motors are operated with electrical $120^{\circ}$ mode as a brushless DC motor (BLDC) and torque versus speed characteristics show a compound DC motor characteristic. The motors can be named as brushless DC compound motors.

Analysis and Application of a Hybrid Motor Structure Convenient to Modify the Magnet and Reluctance Torques on the Rotor

Beser, Esra Kandemir,Camur, Sabri,Arifoglu, Birol,Beser, Ersoy The Korean Institute of Electrical Engineers 2012 Journal of Electrical Engineering & Technology Vol.7 No.3

This paper presents a hybrid motor prototype convenient to modify the magnet and reluctance torques. The rotor of the prototype consists of magnet and reluctance parts, so the generated torque includes both magnet and reluctance torques. A considerable feature of the motor is that the ratio of the magnet and reluctance parts can be modified on the rotor and the rotor hybridization ratio can be varied. Another important point is the mechanical angle between the parts changed by means of the suitable construction of the parts on the rotor shaft. Finite element (FE) analysis was carried out for the proposed motor and static torque measurements were realized. The FE results were compared with the experimental results. Average torque and maximum torque values were obtained and three dimensional 3-D graphs were formed by using the experimental data. It is possible to make different combinations by changing the parts and the angle between the parts due to the proposed motor. So the magnet and reluctance torques are modified and different combinations give different torque behavior.

Evaluation of Oxidative Metabolism in Child and Adolescent Patients with Attention Deficit Hyperactivity Disorder

Muslum Kul,Fatih Unal,Hasan Kandemir,Bahram Sarkarati,Kamer Kilinc,Sultan Basmacı Kandemir 대한신경정신의학회 2015 PSYCHIATRY INVESTIGATION Vol.12 No.3

ObjectiveaaOxidative metabolism is impaired in several medical conditions including psychiatric disorders, and this imbalance may be involved in the etiology of these diseases. The present study evaluated oxidative balance in pediatric and adolescent patients with attention deficit hyperactivity disorder (ADHD). MethodsaaThe study included 48 children and adolescents (34 male, 14 female) with ADHD who had no neurological, systemic, or comorbid psychiatric disorders, with the exception of oppositional defiant disorder (ODD), and 24 sex- and age-matched healthy controls (17 male and seven female). ResultsaaTAS was significantly lower, and TOS and OSI were significantly higher in patients with ADHD than in healthy controls. Total antioxidant levels were lower in patients with comorbid ODD than in those with no comorbidity. No difference was found in TOS or OSI among the ADHD subtypes; however, TAS was higher in the attention-deficient subtype. ConclusionaaOur findings demonstrated that oxidative balance is impaired and oxidative stress is increased in children and adolescents with ADHD. This results are consistent with those of previous studies.

Investigation of Dysregulation of Several MicroRNAs in Peripheral Blood of Schizophrenia Patients

Mehmet Akif Camkurt,Fatih Karababa,Mehmet Emin Erdal,Hüseyin Bayazıt,Sultan Basmacı Kandemir,Mustafa Ertan Ay,Hasan Kandemir,Özlem İzci Ay,Erdinç Çiçek,Salih Selek,Bahar Taşdelen 대한정신약물학회 2016 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.14 No.3

Objective: The prevalence of schizophrenia is 1%, and it is a debilitating disorder that often results in a shortened lifespan. Peripheral blood samples are good candidates to investigate because they can be easily drawn, and they are widely studied in psychiatric disorders. MicroRNAs are small non-coding RNA transcripts. They regulate the expression of genes by binding to the 3’-untranslated region (UTR) of mRNAs and pointing them to degrade. In this study, we aimed to investigate the expression of miR-9-5p, miR-29a-3p, miR-106-5p, miR-106b-5p, miR-107, miR-125a-3p, and miR-125b-3p in schizophrenia patients and healthy controls. Methods: We collected blood samples from 16 patients with schizophrenia and 16 healthy controls. MicroRNAs were measured with reverse transcriptase polymerase chain reaction. Results: Schizophrenia patients showed statistically significant upregulation of five microRNAs: miR9-5p (p=0.002), miR29a-3p (p<0.001), miR106b-5p (p=0.002), miR125a-3p (p<0.001), and miR125b-3p (p=0.018). Conclusion: Our results increased the value of the miR106 and miR29 families as potentially and consistently dysregulated in psychiatric disorders. Our results should be considered preliminary, and they need confirmation in future studies with larger sample sizes.

Impact of root canal curvature and instrument type on the amount of extruded debris during retreatment

Serefoglu Burcu,Kandemir Demirci Gözde,Miçooğulları Kurt Seniha,Kaşıkçı Bilgi İlknur,Çalışkan Mehmet Kemal 대한치과보존학회 2021 Restorative Dentistry & Endodontics Vol.46 No.1

Objectives: The aim of the current study was to assess whether the amount of extruded debris differs for straight and severely curved root canals during retreatment using H-files, R-Endo, Reciproc and ProTaper Universal Retreatment (PTU-R) files. Additionally, the area of residual filling material was evaluated. Materials and Methods: Severely curved (n = 104) and straight (n = 104) root canals of maxillary molar teeth were prepared with WaveOne Primary file and obturated with gutta-percha and AH Plus sealer. Root canal filling materials were removed with one of the preparation techniques: group 1: H-file; group 2: R-Endo; group 3: Reciproc; group 4: PTU-R (n = 26). The amount of extruded material and the area of the residual filling material was measured. The data were analyzed with 2-way analysis of variance (ANOVA) and 1-way ANOVA at the 0.05 significance level. Results: Except for Reciproc group (p > 0.05), PTU-R, R-Endo, and H-file systems extruded significantly more debris in severely curved canals (p < 0.05). Each file system caused more residual filling material in severely curved canals than in straight ones (p < 0.05). Conclusions: All instruments used in this study caused apical debris extrusion. Root canal curvature had an effect on extruded debris, except for Reciproc system. Clinicians should be aware that the difficult morphology of the severely curved root canals is a factor increasing the amount of extruded debris during the retreatment procedure.

Design and Application of a Single Phase Multilevel Inverter Suitable for using as a Voltage Harmonic Source

Ersoy Beser,Birol Arifoglu,Sabri Camur,Esra Kandemir Beser 전력전자학회 2010 JOURNAL OF POWER ELECTRONICS Vol.10 No.2

This paper presents a single phase multilevel inverter for using as a voltage harmonic source. First, a single phase multilevel inverter system is presented and the structural parts of the inverter are described. In order to obtain multilevel output voltage waveforms, a switching strategy based on calculating switching angles is explained and an improved formula for determining switching angles is given. Simulation and experimental results of multilevel voltage waveforms are given for 15, 31 and 127 levels. The proposed topology does not only produce output voltages with low THD values. It also produces the required harmonic components on the output voltage. For this purpose, equations for switching angles are constituted and the switching functions are obtained. These angles control the output voltage as well as provide the required specific harmonics. The proposed inverter structure is simulated for various functions with the required harmonic components. The THD values of the output voltage waves are calculated. The simulated functions are also realized by the proposed inverter structure. By using a harmonic analyzer, the harmonic spectrums, which belong to the output voltage forms, are found and the THD values are measured. Simulation and experimental results are given for the specific functions. The proposed topology produces perfectly suitable results for obtaining the specific harmonic components. Therefore, it is possible to use the structure as a voltage harmonic source in various applications.

FIRM INNOVATIVENESS OF VERTICAL ALLIANCE PORTFOLIO IN NEW PRODUCT DEVELOPMENT

Teck-Yong Eng,Sena Ozdemir,Destan Kandemir 글로벌지식마케팅경영학회 2014 Global Marketing Conference Vol.2014 No.1

Vertical alliances for collaborative new product development in interfirm relationship have been an ongoing theme of strategy and marketing research to cope with fast changing environments, and to continuously innovate in the marketplace. However, no study has yet examind both direct and indirect effects of vertical alliances on new product performance under high technology turbulence. As alliance partners seek to enhance their collaboration and performance, the relational nature of business relationships and structural network positions can influence firm innovativeness and subsequent new product performance. Using survey data of 146 firms collected in Turkey, this study shows that while firms form stronger cooperation under conditions of high technology turbulence, the impact on firm innovativeness and new product performance is contingent upon network positions and information exchange. The findings indicate that indirect effects of vertical alliance portfolio and information exchange enhance new product performance through firm innovativeness. Vertical relationship structures facilitate firm innovativeness with enhanced exploration but may not have a positive direct effect on new product performance. Furthermore, the effect of information exchange on new product performance is contingent upon information exchange which enhances firm innovativeness.