Yazarlar
- Abdioglu, M.(2)
- Abdalsalam, Alyaa H.(1)
- Acar, Irfan(1)
- Acar, S.(1)
- Aktaş, Ayşe(1)
- Alim, Bunyamin(1)
- Arslan, Tayfun(1)
- Badica, P.(1)
- Bahadir, M. V.(1)
- Barroso, Joaquim José(1)
- Bute, Musa(1)
- Cansiz, A.(1)
- Cuce, Erdem(1)
- Demirkol, Dilek Odaci(1)
- Enculescu, M.(1)
- Ertugrul, Mehmet(1)
- Guner, S. B.(1)
- Hasar, Ugur Cem(1)
- Ionescu, A. M.(1)
- Kabaer, M.(1)
- Kaky, Kawa M.(1)
- Kaya, Yunus(1)
- Khammas, Abbas(1)
- Kocadagistan, Mustafa Engin(1)
- Kumar, Ashok(1)
- Locovei, C.(1)
- Mhareb, M. H. A.(1)
- Ozturk, K.(1)
- Ozturk, U. K.(1)
- Patel, A.(1)
- Sakar, Betul Ceviz(1)
- Sakar, Erdem(1)
- Savaskan, B.(1)
- Sayyed, M. I.(1)
- Serencam, Hüseyin(1)
- Somer, M.(1)
- Timur, Suna(1)
- Topçu, Saim(1)
- Yalcinkaya, Esra Evrim(1)
- Yilmaz, Yahya Yasin(1)
Yayınlar
- MakaleYalnız künye2023Scopus SJRQ1Bulk MgB2 superconductor for levitation applications fabricated with boron processed by different routes
Savaskan, B.; Ozturk, U. K.; Guner, S. B.; Abdioglu, M.; Bahadir, M. V.; Acar, S.; Somer, M.; Ionescu, A. M.; Locovei, C.; Enculescu, M.
Bulk MgB2 discs were prepared by an in situ route from mixtures of magnesium and boron powders. The boron powders were produced by two methods. The first one consisted of a self-propagating high tem-perature magnesiothermic synthesis (SHS) process followed by acid and fluorine cleaning and a heat treatment in inert atmosphere. This approach produced boron with purities between 86 % and 97 %, where the main impurity was Mg. Depending on the final heat treatment, these boron powders were amorphous or crystalline. In the second route, high purity nano powders (99 %) of boron were obtained by a diborane pyrolysis process. Bulks of MgB2 were characterized by structural, microstructural, and magnetic mea-surements. Critical current density, pinning force aspects and levitation force (including guiding force) details were assessed. Amorphous lower purity boron (86-97 %) obtained by the first processing route was found to promote the largest levitation forces of the MgB2 bulks and, among these samples, the best le-vitation results were recorded when using boron with a purity of 95-97 %. Use of a lower purity boron that decreases the cost of MgB2 promotes large scale production at industrial level of bulk MgB2 super-conducting magnets for levitation applications and enhances the applicability potential of MgB2 super-conductor. The relationship between levitation force and specific features of the samples such as pinning force details are discussed.& COPY; 2023 Elsevier B.V. All rights reserved.
AtıfScopus10WoS10OpenAlex12
İncele - MakaleYalnız künye2020Scopus SJRQ14-aminothiophenol-intercalated montmorillonite: Organic-inorganic hybrid material as an immobilization support for biosensors
Yilmaz, Yahya Yasin; Yalcinkaya, Esra Evrim; Demirkol, Dilek Odaci; Timur, Suna
Hybrid materials containing organic and inorganic structures are very important because they have the advantages of each of their components. Intercalation of the organic molecule to inorganic structures such as clay allows the preparation of multifunctional new immobilization matrices that contain both the strength properties of the clays and the properties of the organic molecule such as its functional groups (amine, carboxyl or hydroxyl etc.). In this study, 4-aminothiophenol intercalated montmorillonite (4ATP-Mt) was prepared and used as an immobilization layer for the pyranose oxidase (PyOx) enzyme on a glassy carbon (GC) electrode. Firstly, 4ATP intercalation of Mt was carried out, and the success of intercalation was proven using Fourier-Transform Infrared Spectroscopy (FTIR), X-ray Diffractometer (XRD), and Thermogravimetric Analysis (TGA) techniques. Then PyOx was immobilized using 4ATP-Mt, BSA and glutaraldehyde as a cross-linker on the surface of GC electrodes. To show the coating steps for the preparation of 4ATP-Mt/PyOx biosensors, cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) techniques were applied, and surface morphology was visualized by scanning electron microscopy (SEM). After optimization of working conditions, analytical performance parameters were determined for glucose detection. The 4ATP-Mt/PyOx biosensor exhibited a wide linear concentration range between 0.01 and 0.5 mM (LOD: 1.0 mu M) for glucose. Additionally, the fabricated 4ATP-Mt/PyOx was assayed for the analysis of glucose in artificial body fluids and drinks.
AtıfWoS40OpenAlex48İncele - MakaleYalnız künye2020Scopus SJRQ2Theoretical and experimental validation gamma shielding properties of B2O3-ZnO-MgO-Bi2O3 glass system
Kaky, Kawa M.; Sayyed, M. I.; Khammas, Abbas; Kumar, Ashok; Sakar, Erdem; Abdalsalam, Alyaa H.; Sakar, Betul Ceviz; Alim, Bunyamin; Mhareb, M. H. A.
In the present work, we fabricated a series of six glasses to be utilized in the field of radiation shielding application. Glasses have been synthesized using a melt-quenching ordinary technique. In this work, we investigated the structural properties of these glasses using Raman spectroscopy. Moreover, optical properties have been studied in the present work. The radiation attenuation ability for the present samples was also investigated and measured using transmission geometry between 81 and 964.1 keV. The mass attenuation coefficient was measured and the results were validated by the WinXcom program. Also, radiation protection efficiency (RPE) was evaluated and discussed in terms of photon energy and Bi2O3 concentration. From RPE curve, we found that the fabricated glasses can be used as effective shielding materials especially for the low energies (81-383 keV). The half value layer also was calculated and the results of this parameter showed that S6 (contains 60 mol% of Bi2O3) has the higher probability of the interaction with gamma photons, leading to less number of photons transmitted this sample and thus better photon attenuator.
AtıfScopus69WoS72OpenAlex76İncele - MakaleYalnız künye2018Scopus SJRQ1Accurate and reliable U-value assessment of argon-filled double glazed windows: A numerical and experimental investigation
Cuce, Erdem
U-value assessment is a significant process to be able to evaluate the thermal insulation performance of building materials notably windows. About 60% of energy losses from building envelope is attributed to windows, hence accurate and reliable thermal resistance evaluation of glazed areas is of vital importance for a sensitive energy demand analysis of buildings. U-value assessment of windows is usually conducted through theoretical and numerical methods in literature. However, dwellers frequently complain about the insufficient thermal insulation performance of commercial glazing products when compared to the reported U-values in datasheets. This inconvenience arises from the lack of comprehensive experimental tests which simulate the actual operating conditions. Therefore, in this research, argon filled double glazed windows, which is one the most common fenestration products in market, is numerically and experimentally analysed in terms of U-value performance. Although computational fluid dynamics (CFD) analyses reveal that the U-value of the reference sample (4 mm pane + 20 mm argon + 4 mm pane) is 0.89 W/m(2)K, which is in good accordance with the theoretical data (0.80 W/m(2)K), it is observed from the environmental chamber tests that the U-value in simulated operating conditions is 1.25, 1.18 and 1.32 W/m(2)K for top, centre and lower positions of the window sample. The tests are repeated for accuracy verification, and the U-value is found to be 1.23, 1.18 and 1.31 W/m(2)K for the said points. In this respect, it is concluded that thermal bridges and edge effects play a key role in actual U-value performance of glazing products. Therefore, experimental performance figures are recommended to be utilised in energy demand analyses of buildings. (C) 2018 Elsevier B.V. All rights reserved.
AtıfWoS72OpenAlex90İncele - MakaleYalnız künye2016Scopus SJRQ1Clarification of magnetic levitation force and stability property of multi-seeded YBCO in point of supercurrent coupling effect
Ozturk, K.; Kabaer, M.; Abdioglu, M.; Patel, A.; Cansiz, A.
In our study as different from the literature, which are mostly related to superconductor fabrication, application and optimization, especially physical origins of bulk supercurrent generation, magnetic levitation and stability properties of the multi-seeded YBCO superconductor are investigated in point of supercurrent coupling effect. Besides the experimental measurements, a simplified simulation of the supercurrent coupling in the multi-seeded bulk YBCO is carried out based on the experimental J(c)(B) data taken from literature and using the critical state method and H-formulation together in COMSOL Multiphysics package, to further elucidate the mechanism of supercurrent generation and guidance force. The bigger guidance force and lateral magnetic stiffness values of PMG-B arrangement with three B-z peaks than the other arrangements with one Bz peak in small cooling height of 5 mm are attributed to the more robust individual intragrain supercurrents, rather than intergrain supercurrent, due to the position coincidence in the z-direction between grains and permanent magnet poles. Additionally, it can be said that PMG-C arrangement with one Bz peak getting to the maximum guidance force value when the cooling height increase from 5 mm to 15 mm, points out for large cooling height the intergrain supercurrents dominate, whereas for the small cooling height the intragrain supercurrents have most effect on the guidance force. Also, performed the supercurrent simulations, using different current flow constraint ratio f (or supercurrent coupling parameter), clearly reproduced the qualitative change in the trapped field profile when the allowed intergrain current compared to no intergrain current (f = 0). It is thought that the presented results, related to the supercurrent generation, coupling mechanism and their effect on levitation and lateral force properties, have utilization potential for researches not only they study on new multiseed superconductor fabrication method, but also they study on superconductor applications. (C) 2016 Elsevier B. V. All rights reserved.
AtıfScopus29WoS30OpenAlex30İncele - MakaleYalnız künye2014Scopus SJRQ2Synthesis and electrochemistry of metallophthalocyanines bearing {4-[(2E)-3-(3,4,5-trimethoxyphenyl)prop-2-enoyl]phenoxy} groups
Acar, Irfan; Arslan, Tayfun; Topçu, Saim; Aktaş, Ayşe; Şen, Serkan; Serencam, Hüseyin
In this study, metallophthalocyanines 4, 5, 6 was carried out by the cyclotetramerization of 4-{3-[(2E)-3-(3,4,5-trimethoxyphenyl)prop-2-enoyl] phenoxy}phthalonitrile 3. The synthesis of metallo derivatives [Zn(II), Co(II), Cu(II)] of phthalocyanines obtained from corresponding phthalonitrile derivative and in the presence of the anhydrous divalent metal salts (Zn(CH 3COO)2, CoCl2 and CuCl2) was described. These phthalocyanines showed good solubility in organic solvents such as chloroform, tetrahydrofuran, DMSO and DMF. The newly synthesized Pcs were verified by IR, 1H NMR, 13C NMR, UV-vis and MS spectral data. The electrochemical properties of the zinc(II), copper(II) and cobalt(II) phthalocyanines were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. The cobalt complex showed a metal based reduction process, while zinc phthalocyanines were giving ligand based electron transfer processes.
AtıfScopus10WoS9OpenAlex12İncele - MakaleAçık Erişim2014Scopus SJRQ1Attractive method for thickness-independent permittivity measurements of solid dielectric materials
Hasar, Ugur Cem; Barroso, Joaquim José; Bute, Musa; Kaya, Yunus; Kocadagistan, Mustafa Engin; Ertugrul, Mehmet
We propose a non-resonant-type method for reference-plane invariant and thickness-independent permittivity measurement of solid dielectric materials when there is no information from permittivity. To achieve this, we derive a branch-index-independent function and verify that it determines the sample thickness and permittivity without resorting to finding the correct branch index value for three different measurement scenarios: (a) measurements at closely separated frequencies of non-dispersive samples, (b) measurements at largely separated frequencies of non-dispersive samples, and (c) measurements at largely separated frequencies of dispersive samples. Via a differential uncertainty analysis, the effect of inaccurate sample thickness on permittivity determination is also presented for demonstration of the improvement achieved by our method. For validation, we measured the permittivity of an approximately 20 mm PTFE sample using the presented method and compared its result with those from other similar methods. From the comparison, we note that the accuracy of tested methods from literature drastically decreases when accurate information of sample thickness is not known (in addition to a further decrease in accuracy when correct transformation factors from reference-planes are not known a priori), while the accuracy of our method is not influenced.
AtıfScopus25WoS22OpenAlex25İncele - DergiSENSORS AND ACTUATORS B-CHEMICAL
- DergiMATERIALS CHEMISTRY AND PHYSICS
- DergiJOURNAL OF ALLOYS AND COMPOUNDS