Scopus İndeksli Yayınlar Koleksiyonu

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Apatinib Sensitizes Human Breast Cancer Cells Against Navitoclax and Venetoclax Despite Up-Regulated Bcl-2 and Mcl-1 Gene Expressions
(Kare Publ, 2021) Kavakcioglu Yardimci, Berna; Ozgun Acar, Ozden; Semiz, Asli; Sen, Alaattin
OBJECTIVE Defects in apoptotic cell death which restrict the success of conventional cytotoxic therapies have pivotal roles in a number of pathological conditions including cancer. However, a novel drug class targeting pro-survival Bcl-2 protein family members has been developed with the understanding of the structures and interactions of Bcl-2 proteins. Within this new class, Bcl-2/Bcl-xL inhibitor Navitoclax and Bcl-2 specific inhibitor Venetoclax have been shown to demonstrate strong anticancer activities on several types of cancers. But their low affinity to other anti-apoptotic proteins limits their clinical usage. Here, we investigated the cytotoxic and apoptotic effects of Navitoclax/Venetoclax and their combinations with specific tyrosine kinase inhibitor Apatinib on estrogen receptor (ER)-positive MCF-7 and ER-negative MDA-MB-231 breast cancer cell lines. METHODS MTT assay was used for the evaluation of the inhibition of cancer cell proliferation. ELISA test and Quantitative real-time PCR assay was performed to determine the role of caspase-3, Bak, Bax, Bcl-2, Bcl-xL and Mcl-1 proteins in the inhibition of cell proliferation triggered by the tested agents. RESULTS We found that aggressive MDA-MB-231 cell line was more sensitive to all tested agents. Apatinib significantly enhanced Navitoclax/Venetoclax mediated inhibition of cell viability in both cancer cell lines despite up-regulation in the expression levels of Bcl-2 and Mcl-1 genes. We further demonstrated significant Bak/Bax and caspase-3 expression in less aggressive MCF-7 cells. CONCLUSION Our findings have impacts on Navitoclax/Venetoclax plus Apatinib based therapy for breast adenocarcinoma. On the other hand, further studies should be conducted to elucidate the mechanisms underlying synergistic effects of Navitoclax/Venetoclax plus Apatinib combinations.
Citation - WoS: 4
Citation - Scopus: 9
Are We Ready for the New Normal in E-Business Education? Sentiment Analysis of Learners' Opinions on MOOCs
(Russian State Vocational Pedagogical Univ, 2021) Derindag, O. F.; Cizmeci, B.
Introduction. The new digital economy and its constantly evolving paradigm have completely transformed the model of doing business and the learning methods. MOOCs (massive-open-online-courses) and micro-credentials are the educations interfaces, have become an important teaching environment tool. Distance learning has become an indispensable alternative teaching method in updating and transferring classical education materials according to real-world settings, especially for learners in higher education. Aim. The current research is aimed to address the society's readiness and attitude direction to the concept of MOOCs and distance learning, highlighting its emergence and inevitability for educational institutions of all types in order to make a fundamental change in their curricula, especially in e-business courses, which are the most demanded training courses on MOOCs platforms. Methodology and research methods. In the study, the awareness and recognition of the online community on the MOOCs concept is examined. in this direction, Turkish people's perception and attitudes toward MOOCs have been addressed via sentiment analysis on Eksi Sozluk, the largest social communication and discussion platform in Turkey. Results. According to the sentiment analysis results, it has been determined that 52% of respondents have positive judgments on distance education and MOOCs, 29% of responses are neutral and 18% are negative. In general, distance education and MOOCs are perceived as a useful new education model by the Turkish people. Scientific novelty. This paper is the first sentiment analysis of learners' opinions on MOOCs and distance learning in Turkey. Considering the increasing awareness of MOOCs and the need for e-business education, as the most demanded type of MOOCs, this is the first study investigating the priority of these two phenomena within the context of COVID-19. Practical significance. It is thought that this study will contribute to the stakeholders in terms of showing how MOOCs and micro-credentials have a high potential to understanding trends in education especially in the new normal after the COVID-19 pandemic. The holistic education model of institutions has difficulty meeting the competitive nature and result-oriented approach of the e-business ecosystem. This market reality requires the institutions to offer more to-the-point and applied education solutions. In terms of e-business (e-commerce, digital marketing) education, the importance of MOOCs as a solution-focused on "how" rather than "what." has been comprehensively discussed in the paper.
Citation - WoS: 76
Citation - Scopus: 83
How Renewable Energy Consumption and Natural Resource Abundance Impact Environmental Degradation? New Findings and Policy Implications From Quantile Approach
(Taylor & Francis inc, 2021) Altinoz, Buket; Dogan, Eyup
The EKC literature has ignored the importance of natural resources on environmental degradation. Thus, this paper aims to investigate the impact of renewable energy consumption and the abundance of natural resources on CO2 emissions for a panel of 82 countries by using quantile regressions. Empirical results show that renewable energy consumption reduces CO2 emissions and its effect increases in higher quantiles. The impact on carbon emissions of natural resource abundance is negative at lower quantiles but positive at medium and higher quantiles. Also, the validity of the EKC hypothesis is confirmed for all quantiles, and an increase in trade openness and urbanization increases environmental degradation in lower and middle quantile levels; however, these determinants have negative impacts on carbon emissions at higher quantiles. Policy implications related to this outcome are further discussed in the study.
Citation - Scopus: 1
Why Is the Lack of Support for Women's Rights Appealing? Considering the Roles of Dispositional System-Justifying Motives and Ambivalent Sexism
(American Psychological Association, 2024) Özdemir, Fatih; Tayyar, Merve; Topuz, Ömer
Although the women's rights movement has made various gains in recent years, there are many negative attitudes toward women and their rights in Turkey. This study aimed to examine the relationship between dispositional system-justifying motives and tendency to support women's rights and to test the mediating role of sexist attitudes in this relationship. A total of 530 Turkish adults participated in the online study, with a mean age of 26.20 years (SD = 5.56). The results show that people with high system justification motivation (including dispositional system-justifying motives, high death anxiety, low need for cognition, and high need for recognition) indicated stronger ambivalent sexism toward women (including hostile and benevolent sexist attitudes). In turn, people with ambivalent sexist attitudes had less willingness to support women's rights (considering attitudes toward women's disadvantaged position in society and awareness and support for the Istanbul Convention). © 2025 Elsevier B.V., All rights reserved.
Citation - WoS: 1
Citation - Scopus: 1
Investigating the Tradeoff Between the MMF Distortion and End Turn Length of a 2-Pole Line Start SynRM Performance
(Springer int Publ Ag, 2023) Tekgun, Didem; Cosdu, Muhammed M.; Tekgun, Burak; Alan, Irfan
Conventional 2-pole AC machine windings have long end windings and generate harmonics, which increase losses and reduce torque density. This study investigates the performance tradeoff between the level of distortion (THD) in winding magneto-motive force (MMF) and end turn length on a 2-pole line start Synchronous Reluctance Machine (LS-SynRM) machine. A two-stage approach is used, winding and geometry optimization. Various multilayer winding configurations having unevenly distributed number of turns are investigated. First, the percentage of the turns in a coil group is optimized for minimum harmonics and end turn length for all structures. Second, geometric optimization is performed on selected winding configurations. Sixteen different configurations are optimized, and Pareto optimal solutions are obtained. Later, these solutions are graded with a new score-based assessment method to quantify the quality of the results. It is concluded that the designs having lower THD in winding MMF perform better than the designs with shorter end turns in terms of efficiency and torque density.
Citation - WoS: 4
Citation - Scopus: 4
Differential in Vitro Anti-Leukemic Activity of Resveratrol Combined With Serine Palmitoyltransferase Inhibitor Myriocin in FMS-Like Tyrosine Kinase 3-Internal Tandem Duplication (FLT3-LTD) Carrying AML Cells
(Springer, 2022) Ersoz, Nur Sebnem; Adan, Aysun
Treatment of FMS-like tyrosine kinase 3 (FLT3)-internal tandem duplication (ITD) AML is restricted due to toxicity, drug resistance and relapse eventhough targeted therapies are clinically available. Resveratrol with its multi-targeted nature is a promising chemopreventive remaining limitedly studied in FLT3-ITD AML regarding to ceramide metabolism. Here, its cytotoxic, cytostatic and apoptotic effects are investigated in combination with serine palmitoyltransferase (SPT), the first enzyme of de novo pathway of ceramide production, inhibitor myriocin on MOLM-13 and MV4-11 cells. We assessed dose-dependent cell viability, flow cytometric cell death and cell cycle profiles of resveratrol in combination with myriocin by MTT assay, annexin-V/PI staining and PI staining respectively. Resveratrol's dose-dependent effect on SPT protein expression was also checked by western blot. Resveratrol decreased cell viability in a dose- dependent manner whereas myriocin did not affect cell proliferation effectively in both cell lines after 48h treatments. Although resveratrol induced both apoptosis and a significant S phase arrest in MV4-11 cells, it triggered apoptosis and non-significant S phase accumulation in MOLM-13 cells. Co-administrations reduced cell viability. Increased cytotoxic effect of co-treatments was further proved mechanistically through induction of apoptosis via phosphatidylserine relocalization. The cell cycle alteration in co-treatment was significant with an S phase arrest in MV4-11 cells, however, it was not effective on cell cycle progression of MOLM-13 cells. Resveratrol also increased SPT expression. Overall, modulation of SPT together with resveratrol might be the possible explanation for resveratrol's action. It could be an integrative medicine for FLT3-ITD AML after investigating its detailed mechanism of action in relation to de novo pathway of ceramide production.
Citation - Scopus: 1
Correlation of PAPP-A Values With Maternal Characteristics, Biochemical and Ultrasonographic Markers of Pregnancy
(Marmara Univ, Fac Medicine, 2021) Kaymakcalan, Hande; Uzut, Ommu Gulsum; Harkonen, Juho; Bakir Gungor, Burcu
Objective: Our aim is to investigate whether there is a correlation of pregnancy-associated plasma protein A (PAPP-A) values with other variables in pregnancy and maternal characteristics. Materials and Methods: We retrospectively analyzed the relation between the PAPP-A levels, demographics, biochemical and ultrasonographic markers of the first trimester screening of 11,842 pregnant women seen at a tertiary hospital between November 2002 and November 2008. Results: A significant difference between PAPP-A values of the diabetic and non-diabetic pregnant women were observed (p=0.0005, Mann-Whitney U test). In terms of weight, crown-rump length, Beta-hCG values, significant differences were observed between low and medium level PAPP-A subgroups and between low and high level PAPP-A subgroups. PAPP-A levels were found to differ significantly between the pregnant women of Caucasian origin and other racial origins. Conclusions: Pregnant women with different ethnic and medical backgrounds have different PAPP-A values and other markers of the aneuploidy screening. 'lb make patient specific risk predictions, understanding these interactions and differences is important. Future studies are needed to understand the pathopyhsiology behind these differences.
Citation - WoS: 1
Citation - Scopus: 1
Simultaneous Low Noise Radio Frequency Tone and Narrow Linewidth Optical Comb Generation From a Regeneratively Mode-Locked Laser
(SPIE - Society of Photo-Optical Instrumentation Engineers, 2014) Ozdur, Ibrahim; Ozharar, Sarper; Delfyett, Peter J.
A regeneratively mode-locked laser with simultaneous low noise radio frequency (RF) tone and optical comb generation is presented. The laser does not need any external RF signal and emits a pulse train at similar to 10 GHz repetition rate with a 1.5-ps optical pulse width after compression. The generated RF tone has a signal-to-noise ratio of 121 dB/Hz and an RF fluctuation of 10(-9) over 0.1 s. The optical frequency comb spacing is also at similar to 10 GHz and the optical comb tooth has a linewidth of <1 kHz. (C) 2014 Society of Photo-Optical Instrumentation Engineers (SPIE)
Use of Confocal Microscopy to Monitor Structural Transformations in Nanopillars Based on DNA and CdSe/CdZnSe Quantum Dots
(Springer, 2023) Motevich, I. G.; Erdem, T.; Akrema, A.; Maskevich, S. A.; Strekal, N. D.
Chip system prototypes in the form of nanopillars were created from DNA complexes with CdSe/CdZnSe/ZnS quantum dots immobilized on a plasmonic gold fi lm by the use of vacuum deposition technology and inorganic synthesis. The design and presence of terminal DNA labeled with Cy3 cyanine dyes makes it possible to carry out the hybridization reaction of this terminal strand with complementary DNA and to control the process by variation of the giant Raman scattering (GRS) and the fluorescence signal. The effect of molecular recognition of complementary DNA is accompanied by a change in the GRS spectrum, a 20-fold increase in the fluorescence intensity, and a decrease in the duration of fluorescence decay.
What Does the Bibliometrics of an Interdisciplinary Field Tell Us?: The Case of Cognitive Science
(Seoul Natl Univ, inst Cognitive Science, 2023) Arik, Beril T.; Arik, Engin
This study investigated the bibliometric characteristics of an interdisciplinary field, Cognitive Science, which consists of contributions from diverse fields such as psychology, computer science, philosophy, linguistics, and anthropology, among others. The results showed that there were 4,711 publications in Web of Science between 1900 and 2017, with an exponential increase in the number of publications in recent years. About two-thirds of publications were classified as social science, of which 41% were in the field of psychology. Seventy percent of the publications were journal articles, half of the publications were written by researchers in the USA, and 95% of the publications were in English. Corpus analyses of abstracts and keywords showed that frequently used words included cognitive, science, research, theory, model, cognition, information, learning, and psychology. These analyses also showed that research in this field centered on the common themes of cognition, information, psychology, language, learning, representation, artificial intelligence, and mind before 2010 and focused on more restricted themes such as embodied and extended cognition, morality and religion, quantum, and music after 2010.
Handling Incomplete Data Classification Using Imputed Feature Selected Bagging (IFBAG) Method
(Ios Press, 2021) Khan, Ahmad Jaffar; Raza, Basit; Shahid, Ahmad Raza; Kumar, Yogan Jaya; Faheem, Muhammad; Alquhayz, Hani
Almost all real-world datasets contain missing values. Classification of data with missing values can adversely affect the performance of a classifier if not handled correctly. A common approach used for classification with incomplete data is imputation. Imputation transforms incomplete data with missing values to complete data. Single imputation methods are mostly less accurate than multiple imputation methods which are often computationally much more expensive. This study proposes an imputed feature selected bagging (IFBag) method which uses multiple imputation, feature selection and bagging ensemble learning approach to construct a number of base classifiers to classify new incomplete instances without any need for imputation in testing phase. In bagging ensemble learning approach, data is resampled multiple times with substitution, which can lead to diversity in data thus resulting in more accurate classifiers. The experimental results show the proposed IFBag method is considerably fast and gives 97.26% accuracy for classification with incomplete data as compared to common methods used.
Citation - WoS: 3
Citation - Scopus: 3
Optimization of Carbon Dioxide Absorption in a Continuous Bubble Column Reactor Using Response Surface Methodology
(Wiley, 2023) Gul, Ayse; Derakhshandeh, Masoud; Un, Umran Tezcan
Carbon dioxide absorption using amine based solvents is a well-known approach for carbon dioxide removal. Especially with the increasing concerns about greenhouse gas emissions, there is a need for an optimization approach capable of multifactor calibration and prediction of interactions. Since conventional methods based on empirical relations are not efficiently applicable, this study investigates use of Response Surface Methodology as a strong optimization tool. A bubble column reactor was used and the effect of solvent concentration (10.0, 20.0 and 30.0 vol%), flow rate (4.0, 5.0 and 6.0 L min-1), diffuser pore size (0.5, 1.0 and 1.5 mm) and temperature (20.0, 25.0 and 30.0 degrees C) on the absorption capacity and also overall mass transfer coefficient was evaluated. The optimization results for maintaining maximum capacity and overall mass transfer coefficient revealed that different optimization targets led to different tuned operational factors. Overall mass transfer coefficient decreased to 34.7 min-1 when the maximum capacity was the desired target. High reaction rate along with the highest absorption capacity was set as desirable two factor target in this application. As a result, a third scenario was designed to maximize both mass transfer coefficient and absorption capacity simultaneously. The optimized condition was achieved when a gas flow rate of 5.9 L min-1, MEA solution of 29.6 vol%, diffuser pore size of 0.5 mm and temperature of 20.6 degrees C was adjusted. At this condition, mass transfer coefficient reached a maximum of 38.4 min-1, with a forecasted achievable absorption capacity of 120.5 g CO2 per kg MEA.
Strand Wire Winding Method in a Solenoidal Coil With Limited Geometry for Good Impedance Matching
(Polska Akademia Nauk, 2023) Kiliç, Veli Tayfun
This paper reports a new strand wire winding method in a solenoidal coil with limited geometry that enables good impedance matching. In the proposed method strand wires are wound layer-by-layer on top of each other allowing one to set equivalent inductance and resistance of the coil to desired values while obtaining dense magnetic flux and high current carrying capacity. As a proof-of-concept demonstration, simple model setups were constructed with solenoidal coils composed of copper wire strands wound according to the proposed method, and a plastic pipe. The measurements were repeated with a metal shell placed inside the coil to model a complete heating system. System inductance and resistance were measured at two different frequencies. The results show that with the new winding method it is possible to increase a coil’s turn number and the number of strand layers composed by the coil. Also, adding and removing strand layers in the proposed coil architectures enable inductance and resistance values to decrease and increase, respectively, in a controlled way. To understand changes of system parameters, simulations were also performed. The calculated inductance and resistance values in the simulations agree well with the measurement results and magnetic flux distribution created in the system demonstrates the changes. © 2023 Elsevier B.V., All rights reserved.
Citation - WoS: 4
Citation - Scopus: 4
Determination of 1/V-T (P, Constant) Diagrams of Hydrogen Gases by Graph-Analytical Methods
(Yildiz Technical Univ, 2017) Ibrahimoglu, Beycan; Dindar, Cigdem Kanbes; Erol, Hazal; Karasari, Salih
Graph-analytical methods provide more accurate results in the analysis of V-T (P=constant) and 1/V-T (P=constant) diagrams of gases. In this study, as a continuation of [1, 2]*, the behavior of hydrogen gas was examined by using graph-analytical method under consideration of volume and density parameters at high pressure and temperature. In this paper, graph-analytical method was applied to draw and examine V-T (P=constant) and 1/V-P (T=constant) diagrams which were based on experimental data of hydrogen and other gases (Hydrogen, carbon dioxide, oxygen, argon, helium, neon, xenon and other gases) at high pressure and temperature. The results indicate that the behavior of hydrogen gas is different from the other gases.
Citation - WoS: 4
Citation - Scopus: 5
The Selection of Washing Machine Programs With Fuzzy Dematel and Moora-Ratio Multi-Criteria Decision-Making Methods Considering Environmental and Cost Criteria
(Elsevier Science inc, 2024) Fidan, Fatma Sener; Aydogan, Emel Kizilkaya; Uzal, Nigmet
The washing machine is the prevalent white household equipment in contemporary society. These machines provide consumers with a range of program options that encompass several variables, including temperature and detergent type. Nevertheless, the selection made by individual customers about the washing machine program they opt for carries substantial environmental consequences during the use stage of textile products. According to studies on the life cycle of clothes, it has been established that the use stage, following the extraction of raw materials, exerts the most substantial influence on environmental impacts. The objective of this research is to assess the washing machine programs provided by the manufacturer through the application of a comprehensive systematic approach for analysis. The evaluation of scenarios for washing machine programs was conducted using the MOORA-Ratio multi-criteria decision-making process. This evaluation considered various parameters, including environmental impact and cost. The life cycle assessment methodology was employed to quantify the environmental impact of the specified criteria. Based on the comprehensive study conducted by integrating criteria across numerous dimensions, it has been determined that the most favorable scenario wass scenario 1, which was developed for the Cotton 20 C program. The primary objective of this research endeavor is to fill a significant need in the current body of literature by undertaking a comprehensive review of washing machine programs that have not been previously recorded. This study employs a comprehensive methodology to investigate the environmental and economic implications linked to these activities, with the objective of delivering significant insights to producers and users.
Citation - WoS: 16
Citation - Scopus: 22
Recovery of Caustic From Mercerizing Wastewaters of a Denim Textile Mill
(desalination Publ, 2015) Varol, Cihangir; Uzal, Nigmet; Dilek, Filiz B.; Kitis, Mehmet; Yetis, Ulku
The objective of this study was to evaluate caustic recovery from mercerizing wastewater originating from a denim textile producing plant using membrane technology. For this purpose, ultrafiltration (UF) and nanofiltration (NF) processes were considered. In the first stage, in an attempt to control the possible membrane fouling, pretreatment alternatives of flocculation, centrifugation, and microfiltration were evaluated. These pretreatment application alternatives were unsuccessful as they did not provide considerable color and solids removal. In the second stage, UF and NF processes were tested using a tight UF membrane (GR95PP, Alfalaval) and three NF membranes (NP010 and NP030, Microdyn Nadir, and MPF34, Koch Membranes) to accomplish the caustic recovery without applying any pretreatment. The best performance was obtained with NP010 NF in terms of permeate flux along with color and COD rejections. Then, for this membrane the effects of transmembrane pressure (4.03 and 6.23 bar), cross-flow velocity (from 0.40 to 1.40 m/s), and feed temperature (20 and 40 degrees C) were investigated. Temperature positively affected the permeate flux without significant loss in recovery and rejections. Caustic stream produced had about 98-100% of NaOH in the feed at a concentration of 30-40 g/L and therefore was recyclable after a concentration process.
Citation - WoS: 4
Citation - Scopus: 4
A New Oval Shaft, High Performance, 2 Pole Line Start Synchronous Reluctance Machine for Submersible Pump Applications
(Ios Press, 2022) Tekgun, Didem; Alan, Irfan
In this paper, a 2 pole, 4 kW, 6 inches diameter line start synchronous reluctance machine (LS-SynRM) as a submersible water pump motor is designed and optimized with a new oval shaft structure. The aim is to improve the machine performance by widening the flux path on the rotor via narrowing down the shaft on the q-axis. This way a wider d-axis flux path is obtained, and accordingly, the d-axis inductance, the saliency ratio L-d/L-q, and the inductance difference L-d-L-q are increased. First, a set of structural analyses is carried out on a 7-flux barrier rotor in 3 stages: modal, harmonic, and static structural analyses. According to analysis results, the safe limit for the shaft size reduction is determined as 8 mm to avoid excessive deformations and undesired vibrations due to resonance. Later, the machine is optimized using Multi-Objective Differential Evolution (MODE) algorithm with a narrower shaft. The quality of the Pareto front solutions shows that the oval shaft machine is superior to the circular shaft machine in terms of efficiency, motor mass, and torque ripple. The maximum recorded efficiency improvement for the same size LS-SynRM is 4 points and the same size commercial induction machine is around 20 points.
Macronutrients in Diets Differentially Affect Gastrointestinal Cytokine and Tight Junction Protein Levels
(Univ Putra Malaysia Press, 2025) Ulutas, M. S.; Cebeci, A.
Western diet is known to result in intestinal inflammation and loss of barrier function. In the present work, we investigated whether other macronutrients contribute to inflammation and destabilising barrier function in mice, without using any inflammatory agents, to see the sole effects of dietary intervention. The present work was designed to determine the direct effects of diet on the intestinal barrier function and inflammation, using eight diets that differed on carbohydrate, fat, and fibre ratios for 17 weeks. At the end of the study, a distinct difference in mRNA expressions of cytokines and tight junction proteins was observed between intestinal and colon samples. Small intestinal cytokine expressions showed no difference among different diets, and tight junction protein expressions were only significant for occludin and ZO-1 in high carbohydrate diets. Colon samples had significantly different TNF alpha and IL-6 expressions among diets, especially in high carbohydrate diets. Tight junction protein expressions also differed significantly among diets, and low carbohydrate zero fibre diet had the lowest expression levels compared to the rest of diets. The present work reveals that not only western diet, but also diets high in carbohydrate negatively affect intestinal health, resulting in significant changes in inflammation markers. The role of carbohydrate and fiber contents are also observed in regulating tight junction protein expression. Based on these findings, adjusting macronutrient ratios can be used as a potential approach to help manage intestinal inflammation, though further research is needed. (c) All Rights Reserved
Citation - WoS: 2
Citation - Scopus: 4
Elliptical Quantum Rings With Variable Heights and Under Spin-Orbit Interactions
(MDPI, 2023) Mora-Ramos, Miguel E.; Vinasco, Juan A.; Radu, A.; Restrepo, Ricardo L.; Morales, Alvaro L.; Sahin, Mehmet; Duque, Carlos A.
We investigate the electronic properties of a semiconductor quantum ring with an elliptical shape and non-uniform height, allowing for distributed quantum-dot-like bulges along its perimeter. The adiabatic approximation and the finite element method are combined to calculate the allowed electron states in the structure under the effective mass approximation, considering the contributions from Rashba and Dresselahaus spin-orbit interactions and the Zeeman effect in the presence of an applied magnetic field. We discuss the features of the calculated spectra for two different ring geometries: a symmetric one with four dot-like bulges, and an asymmetric one with three hilled protuberances. The information about those states allows us to evaluate the linear optical absorption response associated with interlevel transitions between the ground and lowest excited states. This phenomenon takes place at resonant energies of only a few milielectronvolts. It is observed that spin-orbit interactions tend to quench this response under zero-field conditions in the case of symmetric confinement.
Citation - WoS: 4
Citation - Scopus: 4
Identification of Non-Proportional Structural Damping Using Experimental Modal Analysis Data
(Jve int Ltd, 2020) Oktav, Akin
A verified computational model of a complex structure is crucial for reliable vibro-acoustic simulations. Mass and stiffness matrices of such a computational model may be constructed correctly, provided all the design information is available. Since it is an unknown, the damping matrix is usually populated through mathematical models based on some assumptions. In the current study, it is proposed to use the identified non-proportional structural damping matrix in the computational model. Structural damping matrix can be identified using the complex frequency response functions obtained from experimental modal analysis data. No matter what type of a damping mechanism a structure has; proportional or non-proportional, the frequency response functions of the system can be measured. First, the calculation procedure for the non-proportional structural damping matrix is explained. The damping matrix of an analytical model is identified successfully using the proposed procedure. The same procedure is then applied through a case study. Computational model of a test vehicle is constructed. Next, the test vehicle is subjected to a modal test to measure the frequency response functions of the structure. Incompleteness of the measured data and the requirements of the procedure are discussed, as well. The described procedure can be used in any model updating framework.

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