Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü / Department of Material Science & Nanotechnology Engineering

Permanent URI for this collectionhttps://gcris3.etu.edu.tr/handle/20.500.11851/279

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Citation - WoS: 5
Citation - Scopus: 5
1,7-Diazaperylene in Organic Field Effect Transistors
(Wiley-V C H Verlag Gmbh, 2022) Yumusak, Cigdem; Mayr, Felix; Wielend, Dominik; Kahraman, Bilge; Kanbur, Yasin; Langhals, Heinz; Irimia-Vladu, Mihai
A thorough material characterization of 1,7-diazaperylene via multiple investigation techniques (cyclic voltammetry, photoluminescence, photoluminescence excitation, impedance spectroscopy) was performed to understand its applicability in organic electronic devices. The recorded data of this perylene derivative was placed in conjunction with the respective data of the parent perylene molecule, and the behavior of this novel compound in organic electronic devices (planar diodes and field effect transistors explained). Although no photovoltaic effect behavior was recorded in planar diodes where 1,7-diazaperylene was employed both as a donor as well as an acceptor, the perylene derivatives proves functional as dielectric layer in organic field effect transistors.
1919 ve 1990 Yılları Arasında "kürdistan"ın Ortadoğu'da Sınırsallaş(ama)ması: Eleştirel Jeopolitik Bir Yaklaşım
(TOBB University of Economics and Technology, Graduate School of Economics and Social Sciences, 2016) Akyol, Naz Duygu; Palabıyık, Mustafa Serdar
This thesis analyses the reasons of why a certain "Kurdistan" could not be established as a geopolitical entity within the Middle East between the years 1919 and 1990. By using critical geopolitics as the theoretical framework, the thesis focuses on the effects of continuous deterritorialization and reterritorialization of the Kurdistan as a geopolitical entity as well as civilizational and ideological geopolitical discourses developed by four states in the region, being Turkey, Iran, Iraq and Syria. A threefold argument is proposed to explain why an independent or an autonomous Kurdistan could not be formed at the chosen time frame. The internal factors underline the traditional tribal and more recent territorial divisions among the Kurdish tribes preventing the Kurds to establish a common geopolitical discourse describing a particular and territorially-defined "Kurdistan". The external factors emphasize the policies and geopolitical discourses developed by states to preserve their territorial integrity and to prevent any separatist tendency within their own states. Finally, the third set of factors cross-linked internal and external factors. It focuses on the cooperative and conflictual transversal connections between sovereign states and Kurdish political movements. Accordingly, some sovereign states tended to cooperate with the Kurdish groups of rival states in a way to undermine the power of the Kurdish groups within itself and some Kurdish political movements tended to cooperate with the neighboring state to undermine the power of the home state. All in all, the period between 1919 and 1990 witnessed the failure of the projects to establish an autonomous if not an independent Kurdistan.
Citation - WoS: 62
Citation - Scopus: 58
Ab Initio Prediction of Semiconductivity in a Novel Two-Dimensional Sb2x3 (x= S, Se, Te) Monolayers With Orthorhombic Structure
(Nature Research, 2021) Bafekry, A.; Mortazavi, B.; Faraji, M.; Shahrokhi, M.; Shafique, A.; Jappor, H. R.; Feghhi, S. A. H.
Sb2S3 and Sb2Se3 are well-known layered bulk structures with weak van der Waals interactions. In this work we explore the atomic lattice, dynamical stability, electronic and optical properties of Sb2S3, Sb2Se3 and Sb2Te3 monolayers using the density functional theory simulations. Molecular dynamics and phonon dispersion results show the desirable thermal and dynamical stability of studied nanosheets. On the basis of HSE06 and PBE/GGA functionals, we show that all the considered novel monolayers are semiconductors. Using the HSE06 functional the electronic bandgap of Sb2S3, Sb2Se3 and Sb2Te3 monolayers are predicted to be 2.15, 1.35 and 1.37 eV, respectively. Optical simulations show that the first absorption coefficient peak for Sb2S3, Sb2Se3 and Sb2Te3 monolayers along in-plane polarization is suitable for the absorption of the visible and IR range of light. Interestingly, optically anisotropic character along planar directions can be desirable for polarization-sensitive photodetectors. Furthermore, we systematically investigate the electrical transport properties with combined first-principles and Boltzmann transport theory calculations. At optimal doping concentration, we found the considerable larger power factor values of 2.69, 4.91, and 5.45 for hole-doped Sb2S3, Sb2Se3, and Sb2Te3, respectively. This study highlights the bright prospect for the application of Sb2S3, Sb2Se3 and Sb2Te3 nanosheets in novel electronic, optical and energy conversion systems.
Citation - Scopus: 1
Acil Yardım Akıllı Turnike Sistemi [conference Object]
(IEEE, 2017) Beytar, Faruk; Budak, Erdem İnanç; Ünlü, Aytekin; Eroğul, Osman
In case of traffic accidents, firearm injuries and explosions, it is necessary to apply a tourniquet in order to survive the injuries of serious extremity injuries and blood loss. There are a few things to consider when applying a tourniquet. If the tourniquet is not tightened enough to stop the blood loss, blood loss continues and the injured person's life becomes dangerous. If excessive pressure is exerted, and if it is not relaxed and squeezed intermittently, it may cause gangrene in the extremity. The purpose of this study is to develop a pneumatic, intelligent tourniquet system that can successfully stop bleeding by automatically applying the necessary pressure to the proximal limb, where it is injured to stop excessive blood loss in extremity injuries. It is thought that the developed system will be widely used in ambulances, first aid kits for vehicles, emergency services for hospitals, first aid organizations, fire trucks, first aid kits for risky workplaces and many similar civilian areas. As the output of this study; an intelligent tourniquet system prototype has been produced that can be used for arm and leg, inflates with an air motor, has an advanced microcontroller that can manage many parameters, has a GPS module that can access the location of the injured person, has a RTC (Real Time Clock) that can calculate elapsed time since the start of the tourniquet, has a pressure sensor that can gage the tourniquet pressure, can display these information on the OLED screen, direct the user with the necessary instructions to apply the tourniquet correctly, and also send messages to the mobile phone via the GSM module on the collected data.
Acil Yardım Akıllı Turnike Sistemi [master Thesis]
(TOBB University of Economics and Technology,Graduate School of Engineering and Science, 2017) Beytar, Faruk; Eroğul, Osman
Traffic accidents, firearm injuries and explosions can result in severe extremity injuries and hemorrhage while bleeding extremity can stop bleeding with a tourniquet if one hand remains intact until the healthcare personnel intervenes. There are a few things to consider when applying a tourniquet. If the tourniquet is not tightened enough to stop the blood loss, blood loss continues and the injured person's life becomes dangerous. If excessive pressure is exerted, and if it is not relaxed and squeezed intermittently, it may cause gangrene in the extremity. It is also very difficult to manually apply the tourniquet with optimum pressure, especially on the leg, when bleeding. The aim of the thesis study is to develop a pneumatic, intelligent tourniquet system that can be used to stop excessive blood loss in extremity injuries by connecting to the proximal limb and applying the necessary pressure automatically to stop the bleeding successfully. It is thought that the developed system will be widely used in ambulances, first aid kits in vehicles, emergency services in hospitals, first aid institutions, fire trucks, first aid kits for risky workplaces under occupational health and safety and many similar civilian areas. As the output of the thesis study; an intelligent tourniquet system prototype has been produced that can be used for arm and leg, inflates with an air motor, has an advanced microcontroller that can manage many parameters, has a GPS (Global Positioning System) module that can access the location of the injured person, has a RTC (Real Time Clock) that can calculate elapsed time since the start of the tourniquet, has a pressure sensor that can gauge the tourniquet pressure, can display these information on the OLED (Organic Light Emitting Diode) screen, direct the user with the necessary instructions to apply the tourniquet correctly, and also send messages to the mobile phone via the GSM (Global System for Mobile Communications) module on the collected data.
Citation - WoS: 77
Citation - Scopus: 74
Adsorption of Habitat and Industry-Relevant Molecules on the Mosi2n4 Monolayer
(Elsevier, 2021) Bafekry, A.; Faraji, M.; Fadlallah, M. M.; Ziabari, A. Abdolahzadeh; Khatibani, A. Bagheri; Feghhi, S. A. H.; Gogova, D.
The adsorption of various environmental gas molecules, including H-2, N-2, CO, CO2, O-2, NO, NO2, SO2 H2O, H2S, NH3 and CH4, on the surface of the recently synthesized two dimensional MoSi2N4 (MSN) monolayer has been investigated by means of spin-polarized first-principles calculations. The most stable adsorption configuration, adsorption energy, and charge transfer have been computed. Due to the weak interaction between molecules studied with the MSN monolayer surface, the adsorption energy is small and does not yield any significant distortion of the MSN lattice, i.e., the interaction between the molecules and MSN monolayer surface is physisorption. We find that all molecules are physisorbed on the MSM surface with small charge transfer, acting as either charge acceptors or donors. The MSN monolayer is a semiconductor with an indirect band gap of 1.79 eV. Our theoretical estimations reveal that upon adsorption of H-2, N-2, CO, CO2, NO, H2O, H2S, NH3 and CH4 molecules, the semiconducting character of MSN monolayer is preserved and the band gap value is decreased to similar to 1.5 eV. However, the electronic properties of the MSN monolayer can be significantly altered by adsorption of O-2, NO and SO2, and a spin polarization with magnetic moments of 2, 1, 2 mu(B), respectively, can be introduced. Furthermore, we demonstrate that the band gap and the magnetic moment of adsorbed MSN monolayer can be significantly modulated by the concentration of NO and SO2 molecules. As the concentration of NO2 molecule increases, the magnetic moment increase from 1 mu(B) to 2 and 3 mu(B). In the case of the SO2 molecule with increasing of concentration, the band gap decreases from 1.2 eV to 1.1 and 0.9 eV. Obviously, our theoretical studies indicate that MSN monolayer-based sensor has a high application potential for O-2, NO, NO2 and SO2 detection.
Citation - WoS: 22
Citation - Scopus: 25
All-Dielectric Self-Cloaked Structures
(American Chemical Society, 2018-05-16) Hayran, Zeki; Kurt, Hamza; Herrero, Ramon; Botey, Muriel M.; Staliunas, Kestutis
A general procedure to design objects that are intrinsically invisible (without the necessity of an external cloak) has not been demonstrated so far. Here we propose a flexible method to design such self-cloaked objects by uncoupling the scattered waves from the incident radiation via judiciously manipulating the scattering potential of the object. We show that such a procedure is able to yield optical invisibility for any arbitrarily shaped object within any specified frequency bandwidth by simply employing isotropic nonmagnetic dielectric materials, without the usage of loss or gain material. The validity of the design principle has been verified by direct experimental observations of the spatial electric field profiles and scattering patterns at the microwave regime. Our self-cloaking strategy may have profound implications especially in noninvasive probing, cloaked sensor applications, and scattering-free non-Hermitian optics based systems. © 2018 American Chemical Society.
Citation - WoS: 14
Citation - Scopus: 15
An Alternative Method for Selective Metal Deposition Onto Flexible Materials
(Elsevier Science Sa, 2008) Demirci Sankır, Nurdan; Claus, Richard O.
in this article, a cost effective and simple method called line patterning is used for patterning of metal thin films deposited onto flexible substrates. Silver, gold and copper thin films have been deposited onto plastic substrates such as polyester, overhead transparency, polyimide and polyether imide and patterned via line patterning method. It was observed that the all metal thin films were electrically conductive and highly adhesive. Morphology of chemically deposited thin metal films was tested using scanning electron microscopy. Room temperature DC conductivities, current densities and power dissipation of these metal films have been investigated. (c) 2007 Elsevier B.V. All rights reserved.
Alternative Scenarios for the Lhc Based Electron-Proton Collider
(Tubitak Scientific & Technological Research Council Turkey, 2024) Akay, Ahmet Nuri; Dagli, Burak; Ketenoglu, Bora; Ozturk, Arif; Sultansoy, Saleh
Construction of the ERLC (twin LC) collider tangential to LHC will allow investigating ep collisions at essentially higher center-of-mass energies than ERL-50 and LHC based ep collider. Luminosity estimations show that values well exceeding 10 34 cm-2s-1 - 2 s - 1 can be achieved for ERLC and HL-LHC based ep colliders. Certainly, proposed ep colliders have great potential for clarifying QCD basics and new physics search in addition to providing precise PDFs for adequate interpretation of the LHC experimental data. Another alternative to the ERL-50 is to construct an e-ring with the same energy and length. In this case, luminosity of order 1034cm-2s-1 34 cm - 2 s - 1 can be reached. The advantage of this option is that the mu -ring can be installed instead of the e-ring as a next stage, which will allow to reach a much higher center of mass energy.
Citation - WoS: 107
Citation - Scopus: 168
Angular Analysis of Bd0 › K * Μ + Μ - Decays in Pp Collisions at ?s=8 Tev With the Atlas Detector
(Springer Verlag, 2018-10) The ATLAS Collaboration; Sultansoy, Saleh
An angular analysis of the decay Bd0 → K∗μ+μ− is presented, based on proton-proton collision data recorded by the ATLAS experiment at the LHC. The study is using 20.3 fb−1 of integrated luminosity collected during 2012 at centre-of-mass energy of s=8 TeV. Measurements of the K* longitudinal polarisation fraction and a set of angular parameters obtained for this decay are presented. The results are compatible with the Standard Model predictions.[Figure not available: see fulltext.]. © 2018, The Author(s).
Citation - WoS: 4
Citation - Scopus: 5
Anomalous Single Production of the Fourth Generation Charged Leptons at Future Ep Colliders
(World Scientific Publ Co Pte Ltd, 2008) Çiftçi, A. K.; Çiftçi, R.; Yıldız, H. Duran; Sultansoy, Saleh
Possible single productions of the fourth standard model family charged leptons via anomalous interactions at the future ep colliders are studied. Signatures of such anomalous processes and backgrounds are discussed in detail.
Citation - WoS: 3
Citation - Scopus: 4
Anomalous Single Production of the Fourth Generation Neutrino at Future Ep Colliders
(Elsevier, 2008) Çiftçi, A. K.; Çiftçi, R.; Sultansoy, Saleh
Possible single productions of the fourth standard model generation neutrino via anomalous interactions at the future ep colliders are studied. Signatures of such anomalous processes and backgrounds are discussed in detail. Discovery limits for neutrino mass and achievable values of anomalous coupling strength are determined. (c) 2008 Elsevier B.V. All rights reserved.
Citation - WoS: 12
Citation - Scopus: 15
Anomalous Single Top Production at the Lhec Based Gamma P Collider
(Elsevier, 2010) Çakır, I. T.; Çakır, O.; Sultansoy, Saleh
The top quark could provide very important information for the Standard Model extensions due to its large mass close to the electroweak symmetry breaking scale. In this work, anomalous single top production is studied by using gamma p -> W(+)b process at the LHeC based gamma p collider. The sensitivity to anomalous coupling kappa/Lambda could be reached down to 0.01 TeV-1. (c) 2010 Elsevier B.V. All rights reserved.
Citation - WoS: 50
Citation - Scopus: 51
Arrays of Aligned Supramolecular Wires by Macroscopic Orientation of Columnar Discotic Mesophases
(Amer Chemical Soc, 2012) Duran, Hatice; Hartmann, Azanza Brigitte; Steinhart, Martin; Gehrig, Dominik; Laquai, Frederic; Feng, Xinliang; Floudas, George
Structure formation, phase behavior, and dynamics of mono-bromo hexa-peri-hexabenzocoronene (HBC-Br) are strongly affected by the confinement of cylindrical nanopores with rigid walls. Using self-ordered nanoporous anodic aluminum oxide (AAO)-containing arrays of aligned nanopores with narrow size distribution as a-confining matrix, pronounced alignment of the HBC-Br columns along the nanopore axes was found to be independent of-the pore diameter. Hence, arrays of one-dimensional supramolecular HBC-Br wires with the columns uniformly oriented along the wire axes on a macroscopic:scale were. obtained, unlike with discotics bearing smaller-cores: The formation of the crystalline herringbone Structure Is shifted to lower temperatures in nanopores with diameters,cif,of a few hundred nanometers, whereas the formation of this low temperature phase is completely suppressed when the pore diameter Is below 20 lattice parameters. Moreover, the cylindrical confinement affects the disk axial dynamics-as well as the distribution of relaxation times.
Asymptomatic Hemochromatosis Case With Hfe C.1007−47g>a, C.340+4t>c Heterozygous Mutations and Alpha Globin −3.7 Kb Deletion
(2019) Çelik, Vesile Deniz; Kılıç, Betül Orhan; Ardıçoğlu Akışın, Nazife Yasemin; Akar, Nejat
Background Hereditary hemochromatosis is a disease associated with iron deposition which is caused by the mutations in “hereditary Fe (iron)” (HFE) gene. Case The 16-year-old male patient was diagnosed with hereditary hemochromatosis after c.1007?47G>A heterozygous c.340+4?T>C heterozygous mutations were detected in HFE gene analysis after a suspicion of hemochromatosis due to increase of hemoglobin value from 14.8?g/dL to 16.8?g/dL and the level of ferritin from 68?ng/ml to 300?ng/ml in routine check-up controls in two-years period. In addition, due to low mean corpuscular volume (MCV) (76?fL), and mean corpuscular hemoglobin (MCH) (26?pg) levels, gene mutation analysis was carried out and the patient was also shown to carry ? thalassemia ?3.7 deletions. Conclusion Early diagnosis of hemochromatosis is important in terms of prognosis and morbidity. We aimed to emphasize that we can easily diagnose the disease by performing genetic analysis in cases with suspected hemochromatosis even they have no complaints.
Citation - WoS: 268
Citation - Scopus: 312
Atlas B-Jet Identification Performance and Efficiency Measurement With Tt¯ Events in Pp Collisions at ?s=13 Tev
(Springer, 2019-11) The ATLAS Collaboration; Sultansoy, Saleh
The algorithms used by the ATLAS Collaboration during Run 2 of the Large Hadron Collider to identify jets containing b-hadrons are presented. The performance of the algorithms is evaluated in the simulation and the efficiency with which these algorithms identify jets containing b-hadrons is measured in collision data. The measurement uses a likelihood-based method in a sample highly enriched in tt¯ events. The topology of the t→ Wb decays is exploited to simultaneously measure both the jet flavour composition of the sample and the efficiency in a transverse momentum range from 20 to 600 GeV. The efficiency measurement is subsequently compared with that predicted by the simulation. The data used in this measurement, corresponding to a total integrated luminosity of 80.5 fb - 1, were collected in proton–proton collisions during the years 2015–2017 at a centre-of-mass energy s= 13 TeV. By simultaneously extracting both the efficiency and jet flavour composition, this measurement significantly improves the precision compared to previous results, with uncertainties ranging from 1 to 8% depending on the jet transverse momentum. © 2019, CERN for the benefit of the ATLAS collaboration.
Citation - WoS: 21
Citation - Scopus: 25
Azo/Metal Transparent Conductive Oxide Thin Films for Spray Pyrolyzed Copper Indium Sulfide Based Solar Cells
(Elsevier, 2018-05-01) Aydın, Erkan; Demirci Sankır, Nurdan
In this study, effects of the aluminum doped zinc oxide (AZO) and metal sandwich structures on the photovoltaic performance of spray pyrolyzed copper indium sulfide (CuInS2) based solar cells have been investigated. Electrical resistivity of the AZO films, 58.5 Omega.cm, has been lowered up to 3.2 x 10(-5) Omega.cm via metal interlayer deposition. All sandwich-structured transparent conductive oxide (TCO) layers have been deposited at room temperature and very low radio frequency power. This not only reduced the manufacturing cost but also eliminated the penetration of undesired elements from TCO layer through the absorber. The maximum figure of merit of AZO/molybdenum/AZO, AZO/copper/AZO and AZO/silver/AZO structures were 2.98 x 10(-6), 1.06 x 10(-3) and 3.91 x 10(-2), respectively. This indicated that maximum optical transmittance with minimum sheet resistance has been obtained for the silver interlayer. Then molybdenum/CuInS2/indium sulfide/zinc oxide/AZO-metal-AZO/nickel/aluminum device structure has been manufactured to investigate the photovoltaic parameters. Although all devices had similar open cell voltage, the short circuit current density (J(sc)) of the devices has been improved more than 17 times with metal incorporation. The highest J(sc) of 10.15 mA/cm(2) has been observed for the solar cell having AZO/silver/AZO layer. Alternating current measurements revealed that silver interlayer produced the highest electron transit- and life-time, which resulted the higher Jsc compare to the other metal interlayers. Finally, we improved the photovoltaic parameters of the thin film solar cells with AZO/silver/AZO layer via tailoring the stoichiometry of the CuInS2 absorber layer. The maximum conversion efficiency of 4.19% has been observed for sulfur/(copper + indium) and sulfur/copper ratios of 0.79 and 1.26, respectively. This value is very promising to utilize the AZO/metal/AZO films as TCO layer in low cost and fully ecofriendly thin film solar cells.
Citation - WoS: 32
Citation - Scopus: 33
Band-Gap Engineering, Magnetic Behavior and Dirac-Semimetal Character in the Mosi2n4 Nanoribbon With Armchair and Zigzag Edges
(Iop Publishing Ltd, 2022) Bafekry, A.; Faraji, M.; Stampfl, C.; Sarsari, I. Abdolhosseini; Ziabari, A. Abdollahzadeh; Hieu, N. N.; Karbasizadeh, S.
Motivated by the recent successful formation of the MoSi2N4 monolayer (Hong et al 2020 Science 369, 670), the structural, electronic, and magnetic properties of MoSi2N4 nanoribbons (NRs) is investigated for the first time. The band structure calculations showed spin-polarization in zigzag edges and a non-magnetic semiconducting character in armchair edges. For armchair-edges, we identify an indirect to direct bandgap shift compared to the MoSi2N4 monolayer, and its energy gap increases with increasing NR width. Anisotropic electrical and magnetic behaviors are observed via band structure calculations at the zigzag and armchair edges, where, surprisingly, for one type of zigzag-edge configuration, we identifed a Dirac-semimetal character. The appearance of magnetism and Dirac-semimetal in MoSi2N4 ribbons can give rise to novel physical properties, which could be helpful in applications for next-generation electronic devices.
Citation - WoS: 28
Citation - Scopus: 29
Bifunctional Zno Nanowire/Znsno3 Heterojunction Thin Films for Photoelectrochemical Water Splitting and Photodetector Applications
(Elsevier B.V., 2022) Tuc Altaf C.; Coskun O.; Kumtepe A.; Sankır, Mehmet; Demirci Sankır, Nurdan
Robust, cost-effective, and scalable solution based chemical bath deposition and ultrasonic spray pyrolysis methods have been applied to fabricate one dimensional (1D) zinc oxide nanowire (ZnO NW) and zinc stannate (ZTO) heterojunction thin films to be employed in photoelectrochemical (PEC) water splitting and UV photodetector (PD) systems. PEC performance evaluation in a three-electrode cell confirmed the positive effect of ZTO on ZnO NW-based photoanode enhancing incident photon-to-current efficiency (IPCE%) two-folds of the pristine ZnO NW at 367 nm wavelength. Responsivity (Rs) and detectivity (D*) values of the pristine ZnO NW-based PD have been increased from 0.5 A.W?1 and 0.5 × 1012 Jones to 1.7 A.W?1 and 1.0 × 1012 Jones with ZTO layer, respectively. © 2022 Elsevier B.V.
BINDING MECHANISM OF CALCIUM AND SODIUM ION OF CavAb CHANNEL
(2015) Baştuğ, Turgut; Çavuş, Murat; Kuyucak, Serdar
Voltaj-kapılı kalsiyum kanalları, nöronlara kalsiyum girişinin birincil düzenleyicileridir [1]. Kalsiyum kanalları beyin fonksiyonları için hayati öneme sahipken onların hasarı veya bozuklukları; acı, epilepsi, migren, ataksi gibi birçok nörolojik hastalığa neden olur. Moleküler dinamik metotlar iyon kanallarının yapı-fonksiyon ilişkilerini çalışmak için tek fiziksel olarak geçerli tekniktir. Seçici biyolojik kanalların geçiş mekanizmasının çok iyonlu doğasını gösteren sodyum ve kalsiyum kanalları bu yöntemlerin uygulamaları olarak sunulmuştur (Şekil 1'de gösterildi). Bu çalışmada, Ca++ kanalı için tek ve çok iyonlu Na bağlama enerjileri sunuldu. Ayrıca bu + kanalın yapı-fonksiyon ilişkisi oluşturmak için bağlanma enerjileri yorumlandı

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