Matematik ve Bilgisayar Bölümü / Department of Mathematics and Computer Science

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Browsing Matematik ve Bilgisayar Bölümü / Department of Mathematics and Computer Science by Author "AKYÜZ, SEVİM"

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    Energy dispersive X-ray fluorescence and neutron activation analyses of sediments from the Turkish coast of the west Black Sea
    (PARLAR SCIENTIFIC PUBLICATIONS (P S P), ANGERSTR. 12, 85354 FREISING, GERMANY, 2003) Mukhamedshina, N. M.; Mirsagatova, A. A.; AKYÜZ, SEVİM; AKYÜZ, ZEKİ TANIL
    Some surface sediment samples, collected from 10 sampling sites of the southwest part of the Black Sea in 1998, were analysed quantitatively by radioisotope energy dispersive X-ray fluorescence (EDXRF) and instrumental neutron activation analysis (INAA) methods. The concentration of U, Th, Sc and some other rare earth elements (REEs) and important heavy metals in the sediment samples are as follows: U (1.5-5.7 mg/kg), Th (1.9-11 mg/kg), Sc (1.7-13 mg/kg), La (7.8-30 mg/kg), Ce (12-68 mg/kg), Nd (9-20 mg/kg), Sm (1.5-5.3 mg/kg), Th (0.18-0.82 mg/kg), Lu (0.06-0.44 mg/kg), Cd (0.10-0.26 mg/kg), Sb (0.036-2.30 mg/kg), Hg (0.02-0.08 mg/kg), and Pb (2-35 mg/kg). The results investigated indicate the presence of correlations between the concentrations of some elements of the sediment samples. The results are also compared to those of other marine sediments.
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    FT-IR spectra of natural loughlinite (Na-sepiolite) and adsorption of pyrimidine on loughlinite
    (ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS, 2004-11-01) AKYÜZ, SEVİM; AKYÜZ, ZEKİ TANIL
    FT-IR spectroscopy has been used to characterise natural loughlinite and the adsorption of pyrimidine. A comparison of the spectra of loughlinite and sepiolite are given. The adsorption of pyrimidine was on the loughlinite Lewis acid cites through the pyrimidine lone pairs. Moreover. some of the adsorbed pyrimidine molecules may coordinate to surface SiOH groups. (C) 2004 Elsevier B.V. All rights reserved.
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    FT-IR spectroscopic investigation of adsorption of pyrimidine on sepiolite and montmorillonite from Anatolia
    (Springer, Van Godewijckstraat 30, 3311 Gz Dordrecht, Netherlands, 2003-06) AKYÜZ, SEVİM; AKYÜZ, ZEKİ TANIL; 10127
    The adsorption of pyrimidine ( PM) on natural montmorillonite and sepiolite from Turkey was investigated by FT-IR spectroscopy. The intercalation of PM within montmorillonite has been shown by X-ray diffraction to increase the interlayer spacing. The spectroscopic results indicate that PM molecules adsorbed on sepiolite are coordinated to Lewis acidic centers or surface hydroxyls by H-bonding interaction through one of the pyrimidine ring nitrogen lone pairs. Moreover, some of the adsorbed PM molecules may enter the interior channels of the sepiolite structure and replace zeolitic water. The intercalated PM molecules within montmorillonite are coordinated to exchangeable cations directly or indirectly through water bridges.
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    FT-IR spectroscopic investigations adsorption of pyrazinamide and 4-aminopyrimidine by clays
    (SPRINGER, VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS, 2004-02) AKYÜZ, SEVİM; AKYÜZ, ZEKİ TANIL
    The adsorption of pyrazinamide (PZA) and 4-aminopyrimidine (4APM) on natural sepiolite, loughlinite (Na-sepiolite), natural and ion-exchanged montmorillonite (Co- or Cu-montmorillonite) has been investigated using FT-IR spectroscopy. The intercalation of pyrazinamide and 4-aminopyrimidine within natural and ion-exchanged montmorillonites has been shown by X-ray diffraction to increase the interlayer spacing. PZA and 4APM interacted with montmorillonites by direct or indirect coordination ( through water molecules) to the exchangeable cations. The spectroscopic results indicate that PZA or 4APM molecules adsorbed on sepiolite and loughlinite are coordinated to Lewis acidic centers or surface hydroxyls by H-bonding interaction through either one of the pyrimidine ring nitrogen lone pairs ( in the case of 4APM) or carbonyl group ( in the case of PZA).