Makale 2010-2019 yılları

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A computer program to help for resolution of complex and poorly resolved Cu2+ and VO2+ ions doped single EPR spectra
(Taylor & Francis, 2009-11-01) Bıyık, Recep; Çemberci, Mustafa; Tapramaz, Recep; 0000-0001-7929-4395; TAEK-ÇNAEM
Complex and poorly resolved Cu2+ and VO2+ doped single-crystal electron paramagnetic resonance (EPR) spectra are some of the serious problems that exist in this area. In order to help the resolution of this sort of spectra, and for easily resolvable spectra as well, a versatile computer program known as EPR RESolution, or EPRES, is presented. All detectable line positions in the single-crystal spectra taken in three mutually perpendicular planes are given as input. The program plots these line positions. The user then manually determines the lines by selecting the true data points on the plot and fitting them to a well-known variation function. If selection is not suitable, the process is canceled and renewed. By this process, as many resolvable lines as in the spectra can be resolved and determined. The user then groups the resolved lines according to the paramagnetic center to which they belong. This includes the attribution of correct nuclear spin I and MI to correct lines. After this step, hyperfine and g tensor elements can be found, constructed, and diagonalized. [Supplemental materials are available for this article. Go to the publisher’s online edition of Spectroscopy Letters for the following free supplemental resource: a copy of the EPRES computer program.]
A portable fast neutron radiography system for nondestructive analysis
(SCİENDO, 2019) Kam, Erol; Reyhancan, İskender Atilla; Bıyık, Recep; 0000-0001-7929-4395; TAEK-ÇNAEM
Depending on the neutron energy used, neutron radiography can be generally categorized as fast and thermal neutron radiography. Fast Neutron Radiography (FNR) with neutron energy more than 1 MeV opens up a new range of possibilities for a nondestructive inspection when the inspected object is thick or dense. Other traditional techniques, such as X-ray, gamma ray and thermal neutron radiography do not meet FNRs penetration capabilities in this area. Because of these distinctive features, this technique used in different industrial applications such as security (cargo investigation for contraband such as narcotics, explosives and illicit drugs ), gas/liquid flow and mixing, radiography and tomography of encapsulated heavy shielded low Z compound materials. The FNR images are produced directly during exposure; the neutrons create recoil protons, the protons activate a scintillator screen, the images can be collected with a computer controlled charge –coupled device (CCD) camera and finally the picture can be saved on a computer for the image processing. The aim of this research is to set up a portable fast neutron radiography (FNR) system and to test it for use in nondestructive testing of different composite materials. Experiments were carried out by using fast portative neutron generator Thermo Fischer MP320.
An EPR study of clinoptilolite from Bigadiç in Turkey
(Elsevier, 2016-01) Bıyık, Recep; Tapramaz, Recep; 0000-0001-7929-4395; TAEK-ÇNAEM
Natural and synthetic zeolites are industrial materials. They are used in many applications as food additives, molecular sieve to trap unwanted ingredients, as heavy metallic ions and groups, as shielding against radiations etc. EPR spectroscopy is a tool to characterize paramagnetic centers and radicals in the zeolite and clay type minerals. In this study natural cliptonilolite obtained from a mine in Bigadiç in western Anatolia, Turkey, was studied using electron paramagnetic resonance spectroscopy (EPR) at room temperature in natural form,following treatment of the samples: adsorbing of CO2, H2S, and SO2 gases, [Cu(H2O)6]2 ions and exposure to gamma rays. Mn atoms become paramagnetic Mn2+ ions when CO2 and H2S gases are adsorbed to clinoptilolite and when SO2 gas is adsorbed the system becomes unstable and the structure of the paramagnetic center changes with time. When Cu2+ ions are adsorbed to the Bigadiç clinoptilolite, the values of the EPR parameters are consistent with the distorted octahedral symmetry environment and after the exposure to gamma rays from a Co-60 source gives O23- radical.
Environmental radioactivity and high incidence rates of stomach and esophagus cancer in the Van lake region: A causal relationship?
(West Asia Organization for Cancer Prevention (WAOCP), 2014) Akan, Zafer; Başkurt, Büşranur; Aslıyüksek, Hızır; Kam, Erol; Yılmaz, Ahmet; Yüksek, Mehmet Bilgehan; Bıyık, Recep; Esen, Ramazan; Koca, Doğan; 0000-0001-7929-4395; TAEK-ÇNAEM
This study examined the incidence rates of cancer cases (averages for 2006-2010) and relationships with environmental radioactivity levels. Soil and water samples were collected from provincial and district centers of Van city and the outdoor gamma doses were determined using a portable gamma scintillation detector. Gross alpha and beta, (226)Ra, (232)Th, and (40)K activities were measured in both tap water and soil samples. Although high rates of stomach and esophagus cancers have been reported previously in Van the underlying reasons have not hitherto been defined. Incidences of cancers were highest in the Gurpınar (326.0) and Ozalp (377.1) counties (p<0.001). As to the results of the gross alpha and gross beta radioactivity measurements in the drinking water, these two counties also had high beta radionuclide levels: Gurpınar (140 mBq/dm³) and Ozalp (206 mBq/dm³). Even if within the normal range, a relation between the higher rate of the incidence of stomach and esophagus cancers with that of the higher rate of beta radionuclide activity was clear. On Spearman correlation analysis, the relation between higher beta radionuclide levels and cancer incidence was found to be statistically significant (p<0.01). According to the results of the analysis, Van residents receive an average 1.86 mSv/y annual dose from outdoor gamma radiation, ingestion of radionuclides in the drinking water, and indoor 222Rn activity. Moreover, gross alpha and beta activities were found to be extremely high in all of the lakes around the city of Van, Turkey. Further investigations with long-term detailed environmental radiation measurements are needed regarding the relationship between cancer cases and environmental radioactivity in the city of Van.
The importance of pre-annealing treatment for ESR dating of mollusc shells: A key study for İsmil in Konya closed Basin/Turkey
(American Institute of Physics, 2018) Ekici, Gamze; Sayın, Ülkü; Aydın, Hülya; Işık, Mesut; Kapan, Sevinç; Demir, Ahmet; Engin, Birol; Delikan, Arif; Orhan, Hükmü; Bıyık, Recep; Özmen, Ayhan; 0000-0001-7929-4395; TAEK-ÇNAEM
Abstract. In this study, Electron Spin Resonance (ESR) spectroscopy is used to determine the geological ages of fossil mollusc shells systematically collected from two different geological splitting at İsmil Location (37.72769 o N, 33.17781o E) in eastern part of Konya. According to the assessment of obtained ESR ages, the importance of pre-annealing treatment emphasize in the case of g=2.0007 dating signal is overlapped with the other signals arisen from short lived radicals that cause the wrong age calculation. To overcome this problem, the samples are pre-annealed at 180°C for 16 minutes and, in this case ESR ages are recalculated for g=1.9973 dating signal. Dose response curves are obtained using 1.9973 signals after pre-annealing treatments for each samples. ESR ages of samples are obtained in the range of 138 ± 38 ka and 132 ± 30 ka (Upper Pleistocene) according to the Early Uranium Uptake model and the results are in good agreement with the estimated ages from stratigraphic and paleontological correlation by geologists. Thus, it is suggested that especially in the case of 2.0007 dating signal cannot been used due to superimposition case, the signal with 1.9973 g value can be used for dating after pre-annealing treatment. The results reports the first ESR ages on shells collected from İsmil Location and highlight the importance of pre-annealing treatment. This study issupported by TUBITAK 114Y237 research project.
Transition metal ions in black tea: an electron paramagnetic resonance study
(Springer, 2010) Bıyık, Recep; Tapramaz, Recep; 0000-0001-7929-4395; TAEK-ÇNAEM
Tea (Camellia Sinensis) is the most widely consumed beverage in the world and is known to have therapeutic, antioxidant and nutritional effects. It contains dimeric flavanols and polyphenols which are known as the most important organic compounds in tea infusions, and can make strong and stable complexes with metal ions. In this study, we carried out a series of electron paramagnetic resonance experiments on well-known paramagnetic transition metal ions, namely Mn2+, Fe3+, Cu2+, VO2+, and Cr3+ doped in black tea cultivated along the shore of BlackSea, Turkey, to see the effects and structures formed.

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