WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/20.500.14517/18

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Analysis and Implementation of Sensorless Pmsm Drive With Reduced Dc-Link Capacitance Under Parameter Variations
(Ieee, 2024) Sumsek, Reha Ozgur; Calik, Ramazan; Yavuz, Fikri Serkan; Kivanc, Omer Cihan
In AC drives used in heating, ventilation and air-conditioning applications, film capacitors are becoming widespread instead of electrolytic capacitors in DC-link. These drives with reduced capacitor value provide cost and volume advantages. However, dc-link oscillation increases due to the reduced capacity value. These oscillations cause instability, overvoltage and an increase in total harmonic distortion (THD). On the other hand, the winding temperatures of these motors, which operate continuously under rated operating conditions, reach 80 degrees C. The stator resistance and rotor flux value, which change with the increase in temperature, cause these drives, controlled without sensors, to operate even more unstable. In this study, a hybrid approach is proposed to improve the performance of the inverter using a 16 mu F film capacitor at the dc-link and to reduce the THD. The active damping method regulates the inverter output voltage for DC-link voltage stabilization. A permanent magnet synchronous machine (PMSM) sensorless speed control based on stator feedforward voltage estimation and a model reference adaptive system (MRAS) based on a multiparameter estimation algorithm is performed to minimize the effects of parameter variations. As a result of the experimental studies, it is observed that the grid input current complies with the IEC61000-3-2 standard, even under severe parameter variations.
Antioxidant Activity, Chemical Composition, and Therapeutic Activity of Essential Oils From Certain Lamiaceae Species in Turkiye
(Marmara Univ, Fac Pharmacy, 2024) Goksu Surucu, Canan; Dumlupinar, Berrak; Gurbuz, Burcak; Seker Karatoprak, Gokce; Bahtiyarca, Reyhan; Ilgun, Selen
The study examined the antioxidant, antimicrobial, and potential anticancer properties of lavandin (Lavandula x intermedia 'Grosso'), oregano (Origanum vulgare 'Ulu & gbreve; Bey'), and sage (Salvia officinalis 'Beyhekim') essential oils (EOs). Chemical analysis revealed that oregano is rich in carvacrol (81.23%), cymene (5.51%), and 18cineole (2.13%). Sage contains notable quantities of alpha- thujone (17.47%), camphor (13.59%), and borneol (12.14%). Lavandin is predominantly composed of linalool (41.10%), linalyl acetate (16.66%), and camphor (10.01%). The antimicrobial tests demonstrated that lavandin EOs exhibited a high inhibition rate of 90.77% at 1000 pg/mL, which subsequently decreased with lower concentrations. The oregano essential oils demonstrated robust antimicrobial activity across all concentrations, with a 10.97% inhibition rate observed even at the lowest concentration. The sage EOs exhibited a rapid decline in antimicrobial activity, reaching 4.97% at the lowest concentration. Both the DPPH and ABTS assays demonstrated that the antioxidant capacity of the essential oils was concentration-dependent. The cytotoxicity values of oregano essential oil were 35.58 at 50 pg/mL, 32.39 at 25 pg/mL, and 30.92 at 12.5 pg/mL. Similar cytotoxicity results were observed for sage and lavandin essential oils. These findings indicate that plant essential oils exert a dose-dependent cytotoxic effect on cell growth, significantly inhibiting cells at high concentrations. The research indicates that essential oils derived from Lamiaceae plants exhibit robust antimicrobial effects against a range of pathogens, suggesting potential applications as alternative therapies for specific microbial infections, comparable to ciprofloxacin at certain concentrations.
Assessing Parents Perception of Environmental Awareness
(Stef92 Technology Ltd, 2013) Ozyaral, O.; Ayra, F.; Kaya, E.
It is inevitable to avoid from the influences of some adversities to arise in the ecosystem as "environmental risks" on our lives. The present study aims to determine the level of perception of parents on environmental awareness and environmental protection and to raise awareness on the environmental value and protection. In the present study, the questionnaires were administered to the parents of two private kindergarten students in Ki{dotless}zi{dotless}ltoprak-Erenköy districts on the Asian side of Istanbul as well as the parents of first and second grade students of a private primary school in Umraniye district on the Asian side of Istanbul. The parents of these first and second grade students and the kindergarten students were asked to fill in these questionnaires. A questionnaire prepared by the researchers and consisting of 76 questions was administered to the parents of the kindergarten students in order to measure their parents' environmental perception, 12 of which were prepared to measure the demographic characteristics and 64 of which were prepared for the perception measurement. In the study, the relations between the socio-economic and demographic characteristics of the parents and their environmental perceptions were tried to be found out. Moreover, to what extent the parents put into practice what they know was analyzed so that it can be shown how the information acquired affects the behavior acquisition. In line with the findings obtained, the fact that the awareness of the parents themselves on environment and ecosystem should be improved so that they can transfer the proper actions and approaches they have internalized to their children was found out. Emphasizing the environmental education in every part of the life and providing this education through non-governmental organizations and the experts and the efficiency of the media in this regard were among the results. In addition, the environmental awareness studies should begin during childhood for the sustainability of the environmental awareness education and the media studies should be heavily focused on so that the socio-cultural behavior changes could be ensured in the society and the social media studies should be made. © SGEM2013 All Rights Reserved by the International Multidisciplinary Scientific GeoConference SGEM.
Capital: an Introduction To the Three Volumes
(Palgrave Macmillan, 2024) Savran, Sungur
Capital: the Book of Communism
(Palgrave Macmillan, 2024) Savran, Sungur
Comparative Analysis of Transaction Performance in Different Virtualization Environments
(Istanbul Univ, 2024) Candemir, Ali Ihsan; Incereis, Nilgun
Virtualization technologies are increasing in importance day by day. The selection of virtualization software is an important factor to realize efficient use of physical hardware. In this study, the Ubuntu 22.04 LTS operating system was run on VirtualBox, VMware, and Docker, which are widely used virtualization software. Then, the Tiobench, Compress-7zip, C-ray, Smallpt, Tachyon, and OSBench tests were performed on the Ubuntu operating system with the Phoronix Test Suite software, and the test results were analyzed and compared. The results demonstrate that Docker outperformed the other virtualization technologies, although not in every test. Owing to its rapid deployment and efficient use of resources, Docker is suitable for applications that require agility and scalability. However, traditional virtualization technologies, such as VMware, may be more suitable for applications that require high security and extensive resource management. In addition, this study provides information that can guide users in selecting virtualization software.
Confusions Concerning Sraffa (and Marx): Reply To Critics
(Palgrave Macmillan, 2024) Savran, Sungur
The Controversy Between the Neo-Ricardians and the Marxists
(Palgrave Macmillan, 2024) Savran, Sungur
Critique of Political Economy
(Palgrave Macmillan, 2024) Savran, Sungur
Design of a Position Controlled Electric Actuator Used in Fluid Control Valves
(IEEE, 2016) Tosun, Gurkan; Kivanc, O. Cihan; Oguz, Ender; Mutlu, Yasar; Ustun, Ozgur
Valves are the main elements for controlling fluids in industry and other application areas. To control flow precisely, valves need a controlled action which leads to implement actuators, gear systems and electronic controllers. Increasing dominance of electrical actuators due to the advantages of easy control and intervention and space-efficient designs brings seldom implementation of hydraulic and pneumatic actuation. In fluid control applications, the main target is to obtain the right position, i.e. angle for rotary actuators, for adjusting flow rate. In this study, the design and implementation of a position controlled electrically actuated valve used for fluid control are presented. The design phases of system universal power supply and electronic control system are given and the experimental results of position control which are representing the validation the design study is also discussed. Also a special current control scheme is used to overcome transient disruptions.
Developed and Characterization of a Novel Cd Doped CeO2 Nanofilm and Application of Methyl Orange Removed by Photodegradation
(Springer, 2025) Söyleyici Çergel, M.; Demir, E.; Kurtaran, S.
Cerium oxide (CeO2) films doped with cadmium (Cd) were synthesized employing the ultrasonic spray pyrolysis technique (USP). The structural, surface, and optical properties of the prepared Cd-doped CeO2 films were also investigated. All films were polycrystalline, exhibiting as cubic fluorite structure. In addition, the optical bandgap obtained using the UV data ranged from 3.23 to 3.52 eV. Cd-doped CeO2 films exhibited Raman scattering, in which the multi-peak setting of the first optical longitudinal mode was observed, indicated the Raman shift of the characteristic peak in the ~ 461 cm−1 range. In addition, the photodegradation capacities of Cd-doped CeO2 films were investigated for the removal of pesticides that pollute human and environmental health. As a result, proposed Cd-doped CeO2 thin films show very high (approximate 80%) photocatalytic activity for removing important pollutants, such as methyl orange dyestuff. Consequently, the CeO2 film doped with Cd can be readily reused for five cycles without a notable alteration in photocatalytic activity. © Indian Association for the Cultivation of Science 2024.
Effect of Atomic Porosity on the Mechanical Properties of Aluminium Polycrystalline Using Molecular Dynamics Simulation
(Elsevier, 2025) Singh, Narinderjit Singh Sawaran; Ali, Ali B. M.; Ameen, Hawzhen Fateh M.; Fahem, Ahmed Salah; Salahshour, Soheil; Eftekhari, S. A.
Materials with polycrystals are employed to produce parts that can withstand a range of forces, extreme temperatures, and harsh conditions. The behavior of crystal groups can vary depending on the arrangement of their atoms. Understanding the movement of molecules is crucial in comprehending the behavior of polycrystals. The resistance and durability of the crystals may be influenced by adjusting their configuration. By combining these elements, their longevity can be extended. The strength, flexibility, and environmentally friendly nature of aluminium composite materials make them popular. Knowing how the porosity in the aluminium can influence its durability is essential. Engineers are applying this research to develop strong aluminium in harsh conditions. Investigating the influence of porosity in materials can lead to the production of more robust aluminium parts. In the present study, the effect of atomic porosity on the mechanical properties of aluminium polycrystals is examined using molecular dynamics (MD) simulation. The results show that at a porosity ratio of 20 %, the ultimate strength and Young's modulus of material increase from 6.563 to 27.175 GPa to 6.749 and 29.720 GPa, respectively, due to the optimization of atomic arrangement and fluctuations within the porous sample. However, as the porosity ratio increased to 60 %, the ultimate strength and Young's modulus decrease to 5.064 and 19.649 GPa, respectively, due to the increased porosity and reduced load-bearing atoms. Understanding the influence of porosity on the mechanical properties of aluminium polycrystals is crucial for improving the durability and longevity of aluminum-based components.
Effect of External Innovation Capacity on Company Level Innovativeness
(Management & Business Acad, 2019) Okatan, Kagan; Alankus, Orhan Behic
This study focuses on the correlation of national innovation inputs and the external innovation environment with the company-level innovation output. Since all companies are aiming at sustainable innovation to ensure sustainable profit growth, the current literature has highlighted the need for a well-structured internal innovation system for innovation success and discussed the factors affecting the performance of organisations. The internal innovation system has its own dimensions that affect the success of the whole system and emphasize the significant impact of firms on innovation results. Do all companies with a high internal innovation competency and a suitable corporate culture have the chance to become worldwide innovative? What are the impacts of the external environment where the companies are located on the innovation success? And how big is the importance of external environmental inputs? This study seeks to answer these questions and draws attention to the appropriate external environment and conditions to increase firms' innovation competencies.
Evaluation of the Effects of Orthopedic Treatment on the Dentofacial Structure and Upper Airway of Subjects With Skeletal Class Iii Malocclusion
(Galenos Publishing House, 2024) Kan, H.; Sözen, T.; Öğretmenoğlu, O.; Ciğer, S.
Objective: The present study aimed to evaluate the effect of rapid maxillary expansion (RME) and face mask treatment on the upper airway in patients with maxillary retrusion in two dimensions using digital cephalograms and volumetric evaluation using acoustic rhinometric measurements. Methods: A total of 22 individuals with a concave profile and skeletal and dental Class III malocclusion during growth and development with a mean age of 9.9±1.38 years were included in the study. A bonded RME appliance and a petit face mask were adapted for the patients. Before treatment (T0) and after maxillary protraction (T1), lateral cephalometric films and acoustic rhinometric recordings were obtained. The dependent sample t-test was used for statistical evaluation. Results: Cephalometric analysis revealed forward movement of the maxilla and backward downward rotation of the mandible. A significant increase was observed in the nasopharyngeal and oropharyngeal regions of the upper airway. Three-dimensional evaluation of the upper airway by acoustic rhinometry revealed only an increase in the volumes of the left nasal cavity after decongestant administration. A statistically significant increase in acoustic rhinometric measurements in nasal valves. When the correlation of the cephalometric findings of the nasopharyngeal region with the acoustic rhinometry findings was examined, no statistically significant relationship was found. Conclusion: As a result of this study, we observed an increase in the cephalometric measurements of the nasopharyngeal and oropharyngeal areas. A significant increase was observed in the minimal cross-sectional area measured by acoustic rhinometry. Copyright© 2024 The Author.
Factors Affecting Thyroid Volume and the Incidence of Nodules With Goiter School-Aged Children
(Istanbul Univ, 2024) Kaba, Sultan; Dogan, Murat; Yavuz, Alpaslan; Kilic, Sinan
Objective: This study aimed to analyze the associations between age, sex, anthropometric factors, and thyroid volume as well as to determine the prevalence of goiter and thyroid nodules in school children. Methods: This study included schools governed by the Ministry of Education in Van province. Sonographic evaluations of thyroid glands were conducted in children aged 6-17 years, and measurements of weight, height, waist circumference, hip circumference, and skinfold thickness were obtained from the participants. Results: A total of 2284 school children were included in the study. The median age of the participants was 11.08 years. It was observed that thyroid volume exhibited a positive correlation with age, body surface area, body mass index, height, weight, waist circumference, hip circumference, triceps skinfold thickness, and subscapular skinfold thickness (p < 0.008). When assessing the association between age and goiter prevalence based on World Health Organization parameters, 10.2% of children and adolescents developed goiter, and 0.8% of these cases also had a nodule. Among girls, the rates were 9.4% and 1% for goiter and nodules, respectively, whereas among boys, the rates were 11.3% and 0.7%, respectively. Conclusions: Thyroid volume was affected by age, weight, subcutaneous tissue thickness, waist circumference, and BSA. Goiter remains a serious public health problem among school-age children in Van province.
Features Of Popular Sport Movies
(Ataturk Universitesi, 2022) Çetinkaya, G.; Kizilçam, M.
The aim of our study is to try to reveal the general features of popular sports movies. The research was pre-pared with the qualitative method and designed in the descriptive survey model. In this context, all sports movies in the IMDb database were scanned and 307 popular movies were included in the study. The data obtained through the SPSS 25.0 program were analyzed. According to the research findings; It is seen that American cinema leads popular sports movies (71.7%). It has been determined that sports is an important content in British cinema (8.5%) and Indian cinema. Boxing (11.7%), American football (11.1%), baseball (9.8%), racing sports (7.8%), basketball (7.2%), football (6.8%), and combat sports (6.2%) are other sports branches that are frequently featured in the films that are the subject of the research. The main theme that stands out in the movies is drama (65.80%). It was found that the other mostly covered themes were comedy (41.69%) and biography (22.80%). It is observed that popular sports movies make a great profit (69.34%). The arithmetic mean of the scores of the movies from the audience was found to be 6.75 out of 10. The metascore arithmetic mean is 48.57 out of 100. It has been concluded that popular sports films, which are one of the important contents for world cinema, have been appreciated by the audience in general, but cannot show the same success in the critics of cinema professionals. © Author(s).
A Generalized System of Fractional Differential Equations of Beam Type: Existence of Solutions and Stability
(Tsing Hua University, 2024) Anber, A.; Dahmani, Z.; Gouari, Y.; Ibrahim, R.W.
We study the existence of solutions and their Ulam-stability for a coupled system of nonlinear fractional differential equations. The fractional calculus is used by assuming the Caputo fractional derivative, which indicates a good record for applications. Our method is based on the theory of fixed points. As a consequence, two main theorems on the existence of solutions are proved. Some examples are provided to illustrate the applications of the obtained results. Another main result of Ulam-Hyers stability of the solutions of the system is also discussed. © 2024, Tsing Hua University. All rights reserved.
How Does Anxiety Disorder Diagnosis Affect Emotion Recognition, Empathy and Social Responsiveness in Adolescence
(Klinik Psikiyatri Dergisi, 2025) Budak, Burcu Yildirim; Gumustas, Funda; Fis, Nese Perdahli
Objective: We aimed to evaluate the association between the existence of an anxiety disorder (AD) diagnosis in adolescents and social cognition skills such as emotion recognition, empathy and social responsiveness and to compare the results with healthy control group (CG). The second aim of study was to compare the factors affecting social cognition skills in adolescents with ADs with CG. Method: Psychiatric assessments and diagnoses were evaluated by clinical interview based on DSM-5 and Kiddieschedule for affective disorders and schizophrenia-present and lifetime version-Turkish Adaptation (K-SADS-PL-T). Wechsler Intelligence Scale for Children-Revised (WISC-R) and Diagnostic Analysis of Nonverbal Accuracy (DANVA) was applied to the participants. Sociodemographic form, Social Responsiveness Scale (SRS), Griffith Empathy Measure (GEM), Strengths and Diffuculties Questionnaire (SDQ), KA-SI Empathic Tendency Scale (KA-SI ETS) were used. Results: 87 admissions in total were examined for our study. 58 (66.6 %) of the admissions were cases with AD and 29 (33.3%) were the control group. AD group consisted of 34 female adolescents (58.6 %), whereas control group consisted of 17 female adolescents (58.6 %). The average age was 14.06 +/- 2.12 (years) and 13.51 +/- 2.23 (years), respectively. The adolescents with AD had significantly higher social responsiveness problem scores than the CG after adjusting hyperactivity levels but no difference was found between the two groups in terms of empathy level and emotion recognition. Discussion: There has been a impairment in social responsiveness in the presence of the AD. It was found that this impairment occurs when anxiety disorder is accompanied by both hyperactivity and low cognitive empathy.
The Impact of Economic Policy Uncertainty on Corporate Diversification: Evidence From Latin American Emerging Economies
(Economics Bulletin, 2022) Sener, P.; Sonmez, F.D.; Tigrel, E.
Recently a fast-growing strand of literature has focused on economic policy uncertainty (EPU) that has prominent impacts on the firms’ decisions. Diversification is one of the important strategies to cope with an unpredictable environment. This study investigates the impact of EPU on corporate diversification. By using 4, 253 firm-year observations from 3 Latin American emerging countries through the period of 2010–2016, the results show an inverse U-shaped relationship between EPU and diversification. The findings demonstrate that after reaching a certain level of EPU, further increases in EPU trigger firms to behave prudently and diversify less. This study contributes to the literature by exploring the possible nonlinear nature of EPU-diversification nexus on emerging countries. © (2022), (Economics Bulletin). All rights reserved.
In the Tracks of Marx's capital Debates in Marxian Political Economy and Lessons for 21st Century Capitalism Introduction
(Palgrave Macmillan, 2024) Savran, Sungur; Tonak, E. Ahmet

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