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    1H NMR study of chiral monoaza-15-crown-5 ether derivative by relaxation time T1
    (Asian Journal Of Chemistry, 2008) Askin, Muzaffer; Koylu, M. Zafer; Tutsi, Mizgin
    Measurement of spin-lattice relaxation time T has been performed for the chiral monoaza-15-crown-5 ether derivative as a function of temperature. Activation energies E. and correlation times (tau(c)) were obtained. The data suggest that the underlying mechanism of relaxation is due to magnetic dipole-dipole interaction.
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    Effect of the transition metal elements on the relaxation times in the agar solutions
    (Asian Journal Of Chemistry, 2007) Askin, Muzaffer
    In this study, the relaxation times of T-1 spin-lattice and T-2 spin-spin are measured by adding the ions such as Mn2+, Cr3+, Fe3+, Ni2+ and Cu2+ in various concentrations to the different concentration of agar solution. The measurement are carried out by using a FT-NMR spectrometer working At the proton resonance 60 MHz at the room temperature. T-1-measurement is realized by the technique of the Inversion Recovery (IR) and the T-2-measurement by that of the Spin-Echo (SE). It is found that the variation of the l/T-1 and l/T-2 with respect to the ion concentration is linear for each agar concentration. Furthermore, the effect of the each ion in favour of the contribution to the relaxation is evaluated depending on epsilon, the 'relaxation-enhancement parameter of the proton added to a solution.
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    The Examination of a Variety of Different Ions Added to the Crown Ether Derivatives with High Field NMR Spectrometer
    (Maik Nauka/Interperiodica/Springer, 2017) Askin, Muzaffer; Zengin, Bilgin; Korunur, Sibel; Kor, Harun; Koylu, M. Zafer
    The current study involves the measurements of T-1 relaxation time of complexes three different crown ethers (4-aminobenzo-15-Crown-5, 1-Aza-18-Crown-6, 1-Aza-15-Crown-5) and two different ions sodium perchlorate (NaClO4), lithium perchlorate (LiClO4) by a 400 MHz NMR spectrometer. The association constants (K-a) of the complexes were determined on the basis of the evaluation of these measurements using the Benesi-Hildebrand method that we have modified. These association constants were consistent with those obtained from H-1 NMR titration technique. As a result, it can be speculated that binding constants could be measured using T-1 relaxation time when chemical shifts are very small or cannot be observed.
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    Temperature Dependence Study of Chiral Ether Derivative by 1H NMR Relaxation Time
    (Asian Journal Of Chemistry, 2014) Ekinci, Arzu; Koylu, M. Zafer; Askin, Muzaffer
    Measurement of spin-lattice relaxation time T-1 has been studied for the N-benzil-2-isobutyl aza-15-crown-5 ether derivative as a function of temperature. The data suggest that the underlying mechanism of relaxation rates is due to magnetic dipole-dipole interaction which is the dominant mechanism for the increase in temperature due to increase in the dipolar relaxation mechanism and, modulated by whole molecular tumbling. From In T-1 versus 1/T graph, activation energies (E-a) and correlation times (tau(c)) were obtained.
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    THERMODYNAMICS IN f (T, ?) GRAVITY
    (Editura Acad Romane, 2015) Askin, Muzaffer; Abedi, Habib; Salti, Mustafa
    In the present study, we discuss a non-equilibrium picture of thermodynamics at the apparent horizon of flat Friedmann-Roberton-Walker universe in f(T,theta) theory of gravity, where T is the torsion scalar and theta is the trace of the energy-momentum tensor. Mainly, we investigate the validity of the first and second laws of thermodynamics in this scenario. We consider two descriptions of the energy-momentum tensor of dark energy density and pressure and discuss that an equilibrium picture of gravitational thermodynamics can not be given in both cases. Furthermore, we also conclude that the second law of gravitational thermodynamics can be achieved both in phantom and quintessence phases of the universe.