Niyazi Bulut - Academia.edu (original) (raw)

Papers by Niyazi Bulut

Türk Doğa ve Fen Dergisi, 2021

Beta trikalsiyum fosfat (β-TCP), X-ışını kırınımı (XRD), Morfoloji Öz: Bu çalışmada, Ti katkısını... more Beta trikalsiyum fosfat (β-TCP), X-ışını kırınımı (XRD), Morfoloji Öz: Bu çalışmada, Ti katkısının Fe esaslı çift fazlı kalsiyum fosfat malzemelerinin yapısal, morfolojik ve termal özellikleri üzerine etkileri araştırılmıştır. X-ışını kırınımı (XRD) analizi, üretilen numunelerin hem hidroksiapatit (HAp) hem de beta trikalsiyum fosfat (β-TCP) fazlarına sahip olduğunu doğrulamaktadır. Ayrıca, Ti katkısındaki artışla β-TCP fazının miktarının arttığı görülmektedir. Fourier dönüşümlü kızılötesi (FTIR) spektroskopisi sonuçları, numunelerdeki karakteristik fonksiyonel grupların varlığını doğrulamaktadır. Ti miktarı morfolojiyi etkilemektedir. Numunelerin ısıl davranışları birbirine benzerdir ve oda sıcaklığından 1000 °C'ye kadar tüm numuneler termal olarak kararlıdırlar. Bu sıcaklık aralığında numunelerdeki kütle kayıpları % 1,63'e eşit veya altındadır.

Journal of the Turkish Chemical Society, Section A: Chemistry, 2015

Accurate state-to-state quantum wave packet calculations of integral cross sections for the title... more Accurate state-to-state quantum wave packet calculations of integral cross sections for the title reaction are presented. Calculations are carried out on the best available ground 12A' global adiabatic potential energy surface of Deskevich et. al.[1]. Converged state-to-state wave packet reaction cross sections with the DCl (v=0, j=0-1; v=1, j=0) reagent have been calculated for the collision energy range from threshold up to 0.5 eV. Accurate product vibrational and rotational distributions of cross sections have been calculated at selected collision energies. State-to-state and total initial-state resolved rate constants of the title reaction have been calculated in a temperature range of 100-300 K. The present accurate calculations at v=0, j=0, J=0 show noticeable differences with previous calculations for the F+HCl reaction. Assuming the reaction coordinate in the F-Cl distance and to estimate the zero point energy in the orthogonal coordinate ...

Optik, 2021

Abstract Pt(dpb)Cl, Pt(Fdpb)Cl, Pt(F2dpb)Cl and Pt(dpb)I complexes are examined by computational ... more Abstract Pt(dpb)Cl, Pt(Fdpb)Cl, Pt(F2dpb)Cl and Pt(dpb)I complexes are examined by computational chemistry method in all aspects. Hartree-Fock (HF) and Density Functional Theory (DFT) methods at B3LYP and M062X level of functions with CEP-4 G, CEP-31 G, CEP-12 G, LANL2DZ, LANL2MB, and SDD basis sets are used in calculation to obtain an optimal level. Spectral analysis (1H-NMR, 13C-NMR, IR and Emission) calculations are reported and compared with the available experimentally data. To discuss activities of the systems at a molecular level, pharmaceutically active four platinum complexes were studied. In addition, biological activity studies of the complexes have been done by using a molecular docking support and finally emission spectra and OLED properties of platinum complexes were examined. For the first time it was found that platinum complexes may have some photoactive chemotherapeutic properties and can be considered as an anticancer drugs.

Journal of the Australian Ceramic Society, 2021

In this study, a more detailed characterization of the un-doped and Ni-doped ZnAl2O4 spinel struc... more In this study, a more detailed characterization of the un-doped and Ni-doped ZnAl2O4 spinel structures prepared via a facile wet chemical route was carried out. Significant effects of the additive of Ni on the ZnAl2O4 structure were observed. For all the samples, the ZnO phase was detected as the second phase, and the third phase of NiO was observed for two samples having the highest Ni content. X-ray diffraction (XRD) results showed that the crystallinity percent, lattice parameter, and volume of the unit cell decreased continuously with adding of Ni. Fourier transform infrared (FTIR) spectra verify the formation of the ZnAl2O4 structure for all the samples. The thermal behaviors, including the recrystallization temperature and mass losses, of the ZnAl2O4 structure, were also affected by the amount of Ni. The morphology varied with adding of Ni. These properties were not reported before.

The Journal of Physical Chemistry A, 2020

Bilecik Şeyh Edebali Üniversitesi Fen Bilimleri Dergisi, 2020

Yüksek kristalleşmeye sahip katkısız ve Co katkılı SnO2 numuneleri başarılı bir biçimde hazırland... more Yüksek kristalleşmeye sahip katkısız ve Co katkılı SnO2 numuneleri başarılı bir biçimde hazırlandı. Co içeriğinin SnO2'nin termal ve morfolojik özellikleri üzerine etkileri araştırıldı. Co ilavesiyle Kristal büyüklüğünde ve birim hücre parametrelerinde değişimler tespit edildi. Co ilavesiyle faz bileşimi değişmedi. Hem X-ışını kırınımı hem de Fourier dönüşümlü kızılötesi sonuçları her bir numune için SnO2 fazının oluşumunu doğruladı. Üretilen numunelerin oda sıcaklığından 900 °C'ye kadar termal kararlılığı gözlendi. Morfoloji Co içeriğinden etkilendi ve enerji dağılımlı X-ışını sonuçları SnO2 yapısı içerisine Co'ın nüfuz ettiğini doğruladı.

Owing to fascinating applications of ZnO in modern devices, it is interesting to explore its more... more Owing to fascinating applications of ZnO in modern devices, it is interesting to explore its more features for future devices. Hence, herein, we have synthesized the high quality ZnO spherical nanoparticles (SNPs) through a facile green synthesis route and robust structural and biomedical studies are carried out. Hexagonal phase with 93.2% crystallinity was confirmed through XRD analysis. ZnO nanoparticles were tested for their bioactivities both in vivo (acute cytotoxicity test) and in vitro (Anti-cancer activities on liver (HepG2) and cervical (Hela) cancer cell lines, stimulatory/inhibitory effects on normal rat splenic cells and hemolytic effects on red blood cells). Results showed that ZnO SNPs has no cytotoxic effects on vital organ like liver and has no hemolytic action on red blood cells. ZnO SNPs showed inhibitory consequence on normal rat splenic cells growth at all tested concentrations. ZnO nanoparticles showed an inhibitory effect on HepG2 cell line. While showed stimul...

Journal of Thermal Analysis and Calorimetry, 2020

The Journal of Physical Chemistry A, 2019

The title reaction and its isotopic variants are studied using quasi-classical trajectory (QCT) (... more The title reaction and its isotopic variants are studied using quasi-classical trajectory (QCT) (without taking into account corrections to account for the possible zero point energy breakdown) and ring polymer molecular dynamics (RPMD) methods with a full dimensional and accurate potential energy surface which presents an exchange barrier of approximately 0.144 eV. The QCT rate constant increases when the temperature decreases from 1500 to 10 K. On the contrary, the RPMD rate constant decreases with decreasing temperature, in semi-quantitative agreement with recent experimental results. The present RPMD results are in between the thermal and translational experimental rate constants, extracted from the measured data to eliminate the initial vibrational excitation of H + 3 , obtained in an arc discharge. The difference between the present RPMD results and experimental values is attributed to the possible existence of non thermal vibrational excitation of H + 3 , not completely removed by the semiempirical model used for the analysis of the experimental results. Also, it is found that below 200 K the RPMD trajectories are trapped, forming long lived collision complexes, with lifetimes longer than 1 ns. These collision complexes can fragment by either redissociating back to reactants or react to products, in the two cases tunneling through the centrifugal and reaction barriers, respectively. The contribution of the formation of the complex to the total deuteration rate should be calculated with more accurate quantum methods, as it has been found recently for reactions of larger systems, and the present four atoms system is a good candidate to benchmark the adequacy of RPMD method at temperatures below 100 K.

Materials Science-Poland, 2019

In the present study, the dopant effect of Zn on the crystal structure, thermal properties and mo... more In the present study, the dopant effect of Zn on the crystal structure, thermal properties and morphology of magnesium aluminate (MgAl2O4) spinel (MAS) structure was investigated. A pure and two Zn-containing MASs (e.g. MgAl1.93Zn0.07O4 and MgAl1.86Zn0.14O4) were synthesized for this purpose via a wet chemical method, and the as-prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, differential thermal analysis (DTA), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy techniques. It was found that the crystal structure, thermal properties and morphology of the MAS system change with the increase in the amount of Zn. MgO phase formation was observed. The values of the lattice parameter, unit cell volume and crystallite size increased, and the crystallinity percentage decreased. The morphology was also affected by adding of Zn.

Bulletin of Materials Science, 2019

Micro-structural changes in zinc oxide (ZnO) nanoparticles induced by the substitution of Zn 2+ i... more Micro-structural changes in zinc oxide (ZnO) nanoparticles induced by the substitution of Zn 2+ in ZnO by a rare earth (RE) metal ion, Sm 3+ , are investigated. Both pristine and Sm-doped ZnO with a nominal doping concentration of 1, 2 and 4% of Sm using a simple wet-chemical synthetic route followed by calcination at a high temperature of 900 • C, are synthesized. Structural investigations are primarily conducted using X-ray powder diffraction (XRPD) and scanning electron microscopy techniques. Evolution of structural parameters (unit cell parameters, average crystallite size, crystallinity percentage, lattice strain, stress, energy density and atomic packing factor) upon Sm doping is investigated together with Rietveld refinement and Le Bail analysis techniques. XRPD data confirmed that the synthesized nanostructures crystallize in a wurtzite hexagonal structure, the dopant Sm is incorporated into the Zn lattice and the annealing treatment plays a crucial role in determining the structural and optical properties of RE-metal-doped nanoparticles. Values of the optical band gap energy estimated from optical absorbance measurements reveal a widening of the band gap.

Astronomy & Astrophysics, 2019

The rate constants for the formation, destruction, and collisional excitation of SH+are calculate... more The rate constants for the formation, destruction, and collisional excitation of SH+are calculated from quantum mechanical approaches using two new SH+2potential energy surfaces (PESs) of4A″ and2A″ electronic symmetry. The PESs were developed to describe all adiabatic states correlating to the SH+(3Σ−) + H(2S) channel. The formation of SH+through the S++ H2reaction is endothermic by ≈9860 K, and requires at least two vibrational quanta on the H2molecule to yield significant reactivity. Quasi-classical calculations of the total formation rate constant for H2(v = 2) are in very good agreement with the quantum results above 100 K. Further quasi-classical calculations are then performed forv = 3, 4, and 5 to cover all vibrationally excited H2levels significantly populated in dense photodissociation regions (PDR). The new calculated formation and destruction rate constants are two to six times larger than the previous ones and have been introduced in the Meudon PDR code to simulate the p...

Ceramics International, 2017

We describe the temperature dependence of the vibrational, rotational and translational partition... more We describe the temperature dependence of the vibrational, rotational and translational partition functions of the activated complex of hydroxyapatite (HAp). Computed data show that the vibrational modes have a larger contribution towards the partition function of HAp compared to the rotational and translational contributions. X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy have been applied for HAp in the temperature range from 730 °C to 1030 °C at steps of 100 °C. Temperature dependent density functional theory (DFT), B3LYP, and Ground State Hartree-Fock (HF) with 6-311G basis set calculations were also applied to HAp to calculate FTIR spectra, HOMO, and LUMO energies, and density of states (DOS), and the results have been compared to experimental findings. The present results underline that experimental measurements and theoretical calculations of unit cell parameters, and the intensities of most of the FTIR data for HAp are nearly independent on temperature.

Progress in Biomaterials, 2016

In present work, the effect of citric acid (CA) addition in different amounts (0, 1, 5 and 10 ml)... more In present work, the effect of citric acid (CA) addition in different amounts (0, 1, 5 and 10 ml) on the structure of hydroxyapatite (HAp) was investigated using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy techniques. The crystallite dimensions, lattice parameters, unit cell volume, crystallinity percentage and Ca/P molar ratio were found to be affected by the CA content. To investigate the influence of CA on the bioactive properties of the HAp samples and to determine the optimum amount of CA, in vitro soaking tests in simulated body fluid (SBF) were performed. Although the samples' morphology was found to be affected by neither the amount of CA nor the soaking time in SBF, the soaking results revealed that the maximum changes in the Ca/P ratio were found for the HAp samples prepared in the presence of the highest amounts of CA, which pointed out to the highest bioactivity of these samples.

Monthly Notices of the Royal Astronomical Society, 2016

The OH + ions are widespread in the interstellar medium and play an important role in the interst... more The OH + ions are widespread in the interstellar medium and play an important role in the interstellar chemistry as they act as precursors to the H 2 O molecule. Accurate determination of their abundance rely on their collisional rate coefficients with atomic hydrogen and electrons. In this paper, we derive OH +-H fine and hyperfine-resolved rate coefficients by extrapolating recent quantum wave packet calculations for the OH + + H collisions, including inelastic and exchange processes. The extrapolation method used is based on the infinite order sudden approach. State-to-state rate coefficients between the first 22 fine levels and 43 hyperfine levels of OH + were obtained for temperatures ranging from 10 to 1000 K. Fine structure-resolved rate coefficients present a strong propensity rule in favour of j = N transitions. The j = F propensity rule is observed for the hyperfine transitions. The new rate coefficients will help significantly in the interpretation of OH + spectra from photon-dominated region (PDR), and enable the OH + molecule to become a powerful astrophysical tool for studying the oxygen chemistry.

Physical chemistry chemical physics : PCCP, Jan 20, 2016

State-to-state cross-sections for the S(+) + H2(v,j) → SH(+)(v',j') + H endothermic react... more State-to-state cross-sections for the S(+) + H2(v,j) → SH(+)(v',j') + H endothermic reaction are obtained using quantum wave packet (WP) and quasi-classical (QCT) methods for different initial ro-vibrational H2(v,j) over a wide range of translation energies. The final state distribution as a function of the initial quantum number is obtained and discussed. Additionally, the effect of the internal excitation of H2 on the reactivity is carefully studied. It appears that energy transfer among modes is very inefficient that vibrational energy is the most favorable for the reaction, and rotational excitation significantly enhances the reactivity when vibrational energy is sufficient to reach the product. Special attention is also paid to an unusual discrepancy between classical and quantum dynamics for low rotational levels while agreement improves with rotational excitation of H2. An interesting resonant behaviour found in WP calculations is also discussed and associated with th...

Nevsehir Bilim Ve Teknoloji Dergisi, Jun 20, 2013

Bu calismada H3+ potansiyel enerji yuzeyi uzerinde H++H2H2++H reaksiyonu kuasiklasik yorunge met... more Bu calismada H3+ potansiyel enerji yuzeyi uzerinde H++H2H2++H reaksiyonu kuasiklasik yorunge metodu kullanilarak reaksiyondinamikleri ve kinetikleri incelendi. Bu anlamda toplam acisal momentum kuantum sayisinin sifir ve sifirdan buyuk bazi degerleriicin reaksiyon ihtimaliyetleri ve reaksiyon tesir kesitleri carpisma enerjisinin fonksiyonu olarak hiz sabitleri ise sicakliga bagliolarak hesaplandi. Sonuclar, giris kanalindaki iki atomlu H2 molekulunun v=0, j=0 baslangic kuantum durumundan, urun molekulunv' = 0 titresim kuantum durumuna reaksiyon ihtimaliyeti b=0 icin bir esik davranisi sergilemedigini gostermektedir. Bununla birlikteurun molekulun titresim kuantum sayisi arttikca reaksiyon ihtimaliyetlerinin bir esik davranisi gosterdigi ve esik enerjisi urunmolekulun titresim kuantum sayisinin artmasi ile buyuk enerji degerlerine dogru kaymakta oldugu gorulmektedir. Buna goreH++H2H2++H reaksiyonunun termonotral bir reaksiyon oldugu soylenebilir. Hiz sabitleri icin 200-1000 0K sicaklik araliginda birArhenus davranisi sergilememektedir. Bu calismada rapor edilen klasik sonuclar ile kuantum mekaniksel sonuclarin birbirleriyleuyum icerisinde oldugu gorulmustur.

The Journal of Chemical Physics, 2015

We present accurate state-to-state quantum wave packet calculations of integral cross sections an... more We present accurate state-to-state quantum wave packet calculations of integral cross sections and rate constants for the title reaction. Calculations are carried out on the best available ground 1 2 A ′ global adiabatic potential energy surface of Deskevich et al.