Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Dertli, Enes(116)
- Şahin, Engin(48)
- Kaya, Yunus(46)
- Özen, Soner(46)
- İspirli, Hümeyra(45)
- Pat, Suat(44)
- Şenay, Volkan(42)
- Korkmaz, Şadan(36)
- Yilmaz, Mustafa Tahsin(33)
- Kutlu, Naciye(32)
- Cuce, Erdem(31)
- Öner, Erdal(31)
- Artar, Musa(30)
- Ertugrul, Mehmet(29)
- Hasar, Ugur Cem(29)
- Mercan, Emin(28)
- Bayraktar, Bülent(27)
- Bayram, Sinan(27)
- Can, Zehra(25)
- Ecem Bayram, Nesrin(25)
- Çolak, Murat(23)
- Özdemir, Akın(23)
- Cuce, Pinar Mert(22)
- Sert, Durmuş(22)
- Ayata, Ümit(21)
- Bayram, Ozkan(21)
- Dirican, Ebubekir(20)
- Abdioglu, Murat(19)
- Ayazoglu, Rabil(19)
- Birinci, Ahmet(19)
- Kamiloğlu, Aybike(19)
- Gerçek, Yusuf Can(18)
- Taylan, Osman(18)
- Tozlu, Alperen(18)
- Gul, Volkan(15)
- Hasar, Ugur C.(15)
- Kadakal, Mahir(15)
- Sagdic, Osman(15)
- Ergün, Mustafa(14)
- Kadakal, Huriye(14)
Yayınlar
- MakaleAçık Erişim2015Scopus SJRQ1Analysis of patent documents with weighted association rules
Altuntas, Serkan; Dereli, Turkay; Kusiak, Andrew
Analysis of relationship among various technologies may result in technology maximizing profits. Weighted association rules are proposed to determine dependencies across technologies. The proposed approach recognizes uneven importance of patents and technology class in terms of their technological impact and commercial significance. The proposed analysis approach is illustrated with a case study.
AtıfScopus46WoS39OpenAlex49
İncele - MakaleYayıncıda açık erişim2015Scopus SJRQ1Monitoring macro voids in mortars by computerized tomography method
Tekin, Ilker; Birgul, Recep; Ozgur Yaman, Ismail; Gencel, Osman; Yilmaz Aruntas, Huseyin
This study aims to investigate the use of ground pumice powder (PP) in cement production and to monitor void developments in mortars by X-ray Computerized Tomography (CT) which is a nondestructive test method. PP-blended cements were produced by replacing ordinary Portland cement with PP at 0% (control), 5%, 10% and 15% by weight. Paste and mortar specimens were manufactured by these blended cements. Some of the physical and mechanical tests are carried out on these mortar specimens. Experimental results showed that macro void developments in 100-day period for mortars with different PP replacement ratios exhibited different reduction in void ratios.
AtıfScopus19WoS17OpenAlex19İncele - MakaleAçık Erişim2015Scopus SJRQ2Isolation and identification of an exopolysaccharide producer Streptococcus thermophilus strain from Turkish yogurt; [Yoğurttan ekzopolisakkarit üreten Streptococcus thermophilus suşunun izolasyonu ve tanımlanması]
Dertli, Enes
Production of exopolysaccharides (EPS) by starter Lactic acid bacteria (LAB) gained special interest due to technological role of these natural polymers. Yogurt samples were collected from different households in Turkey and bacterial strains were isolated and evaluated for EPS production. Strains potentially producing EPS were then identified to species level with 16S rRNA sequencing. An EPS producer Streptecoccus thermophilus strain was identified from yogurt samples. EPS was extracted from culture supernatants of S. thermophilus and partially purified and structural analysis of the crude EPS by FTIR spectroscopy revealed the presence of typical functional groups related to exopolysaccharides. This study explains the identification of a potential starter culture for yogurt production with EPS production.
AtıfScopus7WoS7OpenAlex1İncele - MakaleYalnız künye2015Scopus SJRQ2Some physical properties of a Si-doped nano-crystalline GaAs thin film grown by thermionic vacuum arc
Şenay, Volkan; Özen, Soner; Pat, Suat; Korkmaz, Şadan
Abstract A 160 nm thick Si-doped nano-crystalline GaAs film was grown on a glass substrate by means of the thermionic vacuum arc in just 50 s. Tools and techniques such as an optical reflectometer, Uv-Vis-NIR spectrophotometer, XRD, FESEM, AFM, Hall effect measurement, and diiodomethane, ethylene glycol, formamide, and water contact angle measurements were employed to investigate some of the physical properties of the produced film. XRD characterization indicated that the film contained GaAs (hexagonal system in atomic ratio of 1) and SiAs (monoclinic system in atomic ratio of 1) phases. The grain size obtained from Scherrer's Formula was in the range of 30-40 nm. The AFM micrographs showed the film topography, revealing a surface root mean square roughness of 14.5 nm and average height of 48.3 nm. From the wetting experiments, it was found that the contact angle value is strongly dependent on the liquid used.
AtıfScopus20WoS18OpenAlex21İncele - MakaleYayıncıda açık erişim2015Scopus SJRQ1Human serum paraoxonase-1 (hPON1): In vitro inhibition effects of moxifloxacin hydrochloride, levofloxacin hemihidrate, cefepime hydrochloride, cefotaxime sodium and ceftizoxime sodium
Türkeş, Cüneyt; Söyüt, Hakan; Beydemir, Şükrü
In this study, we investigated the effects of antibacterial drugs (moxifloxacin hydrochloride, levofloxacin hemihidrate, cefepime hydrochloride, cefotaxime sodium and ceftizoxime sodium) on human serum paraoxonase-1 (hPON1) enzyme activity from human serum in vitro conditions. For this purpose, hPON1 enzyme was purified from human serum using simple chromatographic methods. The antibacterial drugs exhibited inhibitory effects on hPON1 at low concentrations. Ki constants were calculated to be 2.641 ± 0.040 mM, 5.525 ± 0.817 mM, 35.092 ± 1.093 mM, 252.762 ± 5.749 mM and 499.244 ± 10.149 mM, respectively. The inhibition mechanism of moxifloxacin hydrochloride was competitive, whereas levofloxacin hemihidrate, cefepime hydrochloride, cefotaxime sodium and ceftizoxime sodium were noncompetitive inhibitors.
AtıfScopus53WoS53OpenAlex57
İncele - MakaleAçık Erişim2015Scopus SJRQ1Investigation of transmitted, reflected, and absorbed powers of periodic and aperiodic multilayered structures composed of bi-anisotropic metamaterial slab and conventional material
Hasar, Ugur Cem; Barroso, Joaquim José; Kaya, Yunus; Karacali, Tehvit; Ertugrul, Mehmet
In this study, we investigate transmitted, reflected, and absorbed powers in forward and backward directions of periodic and aperiodic multilayered structures composed of bi-anisotropic metamaterial (MM) slab and conventional material. Aperiodic multilayered structure is realized by a change in thickness of any bi-anisotropic MM slab or of any conventional material. From this analysis, we note the following key results. First, identical (non-identical) forward and backward transmitted (reflected and absorbed) powers are observed for the analyzed periodic and aperiodic multilayered structures due to reciprocity (reflection-asymmetry) of bi-anisotropic MM slabs. Second, thickness-resonance phenomenon of conventional materials produces some peaks in the transmitted powers of periodic multilayered structures aside from the resonance frequency region of bi-anisotropic MM slabs. Third, each thickness-resonance frequency splits into many frequencies upon increasing the number of sections of periodic multilayered structures (no splitting when number of periods is one). Fourth, while the effect of changing the thickness of any bi-anisotropic MM slab within the aperiodic multilayered structure has no considerable effect around the resonance region of bi-anisotropic MM slabs (resonance of resonating structures such as MM slabs does not change with thickness), the same change in thickness of the conventional material drastically alters forward/backward reflected and absorbed powers aside from the resonance region of bi-anisotropic MM slabs (thickness-resonance totally depends on the value of thickness of conventional materials). The outcomes presented here can be particularly useful for propagation-related applications requiring cascade connection of various MM slabs.
AtıfScopus14WoS14OpenAlex15İncele - MakaleAçık Erişim2015Scopus SJRQ2Investigation of Comet Wild-2 in terms of effective atomic numbers
Han, Ibrahim; Ün, Adem; Alimb, Bünyamin
Effective atomic numbers (Z eff ) and effective electron densities (N el ) of 69 samples collected from Comet Wild-2 within scope of Stardust mission were determined in the energy range from 1 keV to 100 GeV. The data were individually evaluated for Wild-2 olivines, pyroxene, FeANi sulfide and silicate glass samples to obtain remarkable information about Comet Wild-2. The photon energy and sample composition dependencies of obtained data were investigated. The results show that Z eff and Nel values depend strongly on chemical composition and interaction photon energy. The result of present study may be providing new and helpful knowledge about the Comet Wild-2 and ourSolar System.
AtıfScopus6WoS6OpenAlex7İncele - MakaleYalnız künye2015Scopus SJRQ2Effect of Er doping on the superconducting properties of porous MgB2
Erdem, O.; Yanmaz, E.
MgB2 bulk sample with porous structure was produced by using the in-situ solid-state reaction method under argon (Ar) atmosphere of 10 bar. Elemental Er in powder form was doped into MgB2 with different compositions (Mg1-xErx)B2, where x = 0.00, 0.03 and 0.05, in order to investigate the effect of rare-earth (RE) element Er on the structural and electromagnetic properties of porous MgB2. The Er-doped samples result in small grain size structure compared to the undoped one. The lattice constants a and c of the doped samples, determined from X-ray diffraction (XRD) analysis, increase with the increasing Er content, and consequently the superconducting transition temperature (Tonsetc) of MgB2, determined from resistivity measurements, is slightly suppressed. Also, the upper critical field (Bc2), the irreversibility field (Birr) and the critical current density (Jc) values are significantly enhanced in the doped samples. For the best sample (x = 0.03), at 15 K under a magnetic field of 4 T, the Jc value reaches 2.4×104 A cm-2, which is higher than that of the porous sample by an order of 103, and the Birr value at 20 K reaches 9.7 T. These results imply that the RE element Er fills the pores, enhances the density and the grain connectivity. Hence, the superconducting properties of the porous MgB2 sample improve by Er doping.
AtıfScopus13WoS11OpenAlex12İncele - MakaleAçık Erişim2015Scopus SJRQ1Levitation and guidance force efficiencies of bulk YBCO for different permanent magnetic guideways
Abdioglu, M.; Ozturk, K.; Gedikli, H.; Ekici, M.; Cansiz, A.
The development of superconductor Maglev systems depends on various disciplinary studies due to the inherent composition of available technologies. Because the fabrication cost is very effective on the Maglev, the requirement of the efficiency improvement focuses the researchers on the design considerations. In this study, the guidance force, the magnetic levitation force (MLF) and magnetic stiffness of different permanent magnetic guideway (PMG) arrangements were investigated in different cooling heights (CH) to enhance the efficiency of Maglev system. The single domain cylindrical bulk YBCO superconductors fabricated by top seeding method with the diameter of 45 mm and the height of 15 mm were used as HTS. Magnetic field distributions of the PMGs were calculated by finite element method to determine optimum HTS-PMG arrangements. We have used auxiliary onboard permanent magnets with YBCOs to improve the MLF of three pole Halbach PMG arrangements. It is seen that the efficiency of Maglev systems can be improved by using suitable HTS-PMG arrangements. In this study cost efficiency of the integrated levitation and guidance force ((Fz)max(Fx)max/(SPMG ∗ Cost)) was also determined. It is inferred from this study that the cooling height and PMG-HTS arrangement are key parameters for guidance force, levitation force, magnetic stiffness and efficiency of Maglev systems. It is believed that this study will supply useful references for practical application of HTS Maglev systems.
AtıfScopus60WoS59OpenAlex61İncele - MakaleYalnız künye2015Scopus SJRQ3Conformational and spectroscopic behaviors of 2,4-xylyl isothiocyanate
Cinar, Mehmet; Karabacak, Mehmet; Chand, Satish; Shukla, Vikas K.; Sinha, Leena; Prasad, Onkar; Singh, Manoj Pratap; Asiri, Abdullah M.
This study aims to identify the conformational and spectroscopic characteristics of 2,4-xylyl isothiocyanate (C9H9NS) compound via experimental and computational methods. To accomplish this, density functional theory (DFT), with the B3LYP functional was used to determine ground state conformation, vibrational wavenumbers and also isotropic chemical shifts of the title molecule. Experimentally, vibrational features of the compound were evaluated by FT-IR and FT-Raman spectroscopic analysis in the solid phase. On the basis of these studies, the conformational and spectroscopic behaviors of 2,4-xylyl isothiocyanate were interpreted. The fundamental vibrational wavenumbers as well as their intensities were computed, and a good correlation between experimental and scaled calculated wavenumbers was observed. The polarizability, first hyperpolarizability and dipole moment values of 2,4-xylyl isothiocyanate were calculated at the same level of theory and basis set. The results show that 2,4-xylyl isothiocyanate molecule possesses nonlinear optical (NLO) behavior with non-zero values. Stability of the molecule arising from hyper-conjugative interactions and charge delocalization was analyzed using natural bond orbital (NBO) analysis.
AtıfScopus7WoS5OpenAlex5İncele - MakaleYalnız künye2015Scopus SJRQ1An experimental and density functional study on conformational and spectroscopic analysis of 5-methoxyindole-2-carboxylic acid
Cinar, Mehmet; Karabacak, Mehmet; Asiri, Abdullah M.
In this article, a brief conformational and spectroscopic characterization of 5-methoxyindole-2-carboxylic acid (5-MeOICA) via experimental techniques and applications of quantum chemical methods is presented. The conformational analysis of the studied molecule was determined theoretically using density functional computations for ground state, and compared with previously reported experimental findings. The vibrational transitions were examined by measured FT-IR and FT-Raman spectroscopic data, and also results obtained from B3LYP and CAM-B3LYP functionals in combination with 6-311++G(d,p) basis set. The recorded proton and carbon NMR spectra in DMSO solution were analyzed to obtain the exact conformation. Due to intermolecular hydrogen bondings, NMR calculations were performed for the dimeric form of 5-MeOICA and so chemical shifts of those protons were predicted more accurately. Finally, electronic properties of steady compound were identified by a comparative study of UV absorption spectra in ethanol and water solution and TD-DFT calculations.
AtıfScopus23WoS22OpenAlex24İncele - MakaleYalnız künye2015Scopus SJRQ2GaN thin film deposition on glass and PET substrates by thermionic vacuum arc (TVA)
Pat, Suat; Korkmaz, Şadan; Özen, Soner; Şenay, Volkan
In this paper, GaN thin film production was realized by thermionic vacuum arc (TVA), a plasma deposition technique, for the first time. We present a new deposition mechanism for GaN thin films with a very short production time. Microstructure properties of samples were analyzed by X-ray diffractometry. The peak at 2θ = 72.88° corresponding to GaN (0004) was detected in XRD spectra. The surface morphology of the deposited GaN films was analyzed using field emission scanning electron microscopy and atomic force microscopy. The surface properties of the produced samples are quite different. The average roughness values were determined to be 0.48 nm for GaN/PET and 1.17 nm for GaN/glass. The optical properties (i.e., refractive index and reflection) were determined using an interferometer. Moreover, the obtained optical data were compared with bulk GaN materials. The refractive indexes were measured as 2.2, 3,0 and 2,5 for the GaN/glass, GaN/PET and bulk GaN, respectively. The transparencies of the different GaN-coated substrates are nearly the same. The obtained band gap values were measured in the energy range of 3.3-3.5 eV. TVA is a novel non-reactive plasma technique for the generation of metal organic thin films. The main advantage of this method is its fast deposition rate without any loss in the quality of the films.
AtıfScopus32WoS31OpenAlex34İncele - MakaleYalnız künye2015Scopus SJRQ1Evaluation of polycyclic aromatic hydrocarbons in Circassian cheese by high-performance liquid chromatography with fluorescence detection
Gul, Osman; Dervisoglu, Muhammet; Mortas, Mustafa; Aydemir, Oguz; Ilhan, Eda; Aksehir, Kubra
Polycyclic aromatic hydrocarbons (PAH) in traditional/industrial smoked and unsmoked Circassian cheeses available in Turkish markets were analysed using solid-phase extraction, followed by high-performance liquid chromatography (HPLC) with fluorescence detection. Mean levels of a total of 9 PAHs in smoked traditional and industrial Circassian cheeses were 19.6 and 6.73μgkg-1, while levels in unsmoked traditional and industrial cheeses were 0.77 and 0.49μgkg-1, respectively. The dominant individual PAHs found were naphthalene and acenaphthene. Benzo[a]pyrene, a marker compound representing carcinogenic PAHs, was found in 90% and 30% of traditional smoked and unsmoked Circassian cheeses, 52% and 24% of industrial smoked and unsmoked cheeses, respectively. Correlation statistical analysis showed that benzo[a]pyrene was a good marker for total 9 PAHs in Circassian cheese samples (rB[a]P/sum of 9 PAHs=0.816, p<0.01) as well as the best marker for 5 carcinogenic PAHs (rB[a]P/carcinogenic PAHs=0.904, p<0.01). Risk assessment conducted using daily intakes of sum of 9 PAH levels found in both traditional and industrial smoked Circassian cheese samples showed high risk compared with unsmoked cheeses.
AtıfScopus22WoS21OpenAlex20İncele - MakaleAçık Erişim2015Scopus SJRQ2Impact of exopolysaccharide production on functional properties of some Lactobacillus salivarius strains
Mercan, Emin; İspirli, Hümeyra; Sert, Durmuş; Yılmaz, Mustafa Tahsin; Dertli, Enes
The aim of this work was to characterize functional properties of Lactobacillus salivarius strains isolated from chicken feces. Detection of genes responsible for exopolysaccharide (EPS) production revealed that all strains harbored a dextransucrase gene, but p-gtf gene was only detected in strain E4. Analysis of EPS production levels showed significant alterations among strains tested. Biofilm formation was found to be medium composition dependant, and there was a negative correlation with biofilm formation and EPS production. Autoaggregation properties and coaggregation of L. salivarius strains with chicken pathogens were appeared to be specific at strain level. An increment in bacterial adhesion to chicken gut explants was observed in L. salivarius strains with the reduction in EPS production levels. This study showed that strain-specific properties can determine the functional properties of L. salivarius strains, and the interference of these properties might be crucial for final selection of these strains for technological purposes.
AtıfScopus19WoS16OpenAlex21İncele - MakaleAçık Erişim2015Scopus SJRQ1Determination of Reference-Plane Invariant, Thickness-Independent, and Broadband Constitutive Parameters of Thin Materials
Hasar, Ugur C.; Kaya, Yunus; Barroso, Joaquim José; Ertugrul, Mehmet
We propose an effective microwave method for reference-plane-invariant and thickness-independent constitutive parameters measurement of thin materials. A function depending only on the interface reflection coefficient to facilitate fast computations of constitutive parameters is derived. In addition to the extraction of sample thickness, the method can also be applied to unique retrieval of constitutive parameters whose electromagnetic properties are yet unknown. We have performed an uncertainty analysis to examine how the accuracy of the method can be improved. Finally, we have compared the proposed method with other similar methods in the literature using measurements of distilled water and a thinner Plexiglas sample (1 mm). From the comparison, we note that the accuracy of our proposed method is not affected by any inaccurate knowledge of reference-plane positions and the sample length (or both) while those of compared methods are seriously decreased.
AtıfScopus53WoS52OpenAlex52İncele - MakaleAçık Erişim2015Scopus SJRQ1Investigation on the morphology and surface free energy of the AlGaN thin film
Özen, Soner; Şenay, Volkan; Pat, Suat; Korkmaz, Şadan
The purpose of this paper is to analyze surface properties of AlGaN thin film produced using thermionic vacuum arc technique. Thermionic vacuum arc is an alternative deposition technique for GaN thin films that produces in a very short production time for GaN-based solid-state applications. XRD results showed that AlGaN thin film with cubic crystal structure on a amorphous glass was grown. Conductivity type of AlGaN thin film is determined as p-type by hot-probe method which is a very simple method. The surface morphology was analyzed and discussed using field emission scanning electron microscopy (FESEM) and atomic force microscopy. The contact angles in four different testing liquid and surface free energy of the AlGaN thin film were investigated by optical tensiometer.
AtıfScopus27WoS27OpenAlex28İncele - MakaleAçık Erişim2015Scopus SJRQ2Simultaneous separation and preconcentration of Cd(II), Co(II), and Ni(II) ions in environmental samples by carrier element-free coprecipitation method prior to their flame atomic absorption spectrometric determination
Duran, Celal; Ozdes, Duygu; Akcay, Hakki Turker; Serencam, Huseyin; Tufekci, Mehmet
ABSTRACT: In the present study, Cd(II), Co(II), and Ni(II) ions were separated and preconcentrated via carrier element-free coprecipitation (CEFC) method by using an organic coprecipitating agent, 1,2-bis-(2-tosyl ethoxy) benzene (BTEB), prior to their flame atomic absorption spectrometric (FAAS) detections. The experimental conditions were optimized in terms of pH of the aqueous solution, BTEB amount, standing time, centrifugation rate and time, and sample volume. Under the optimum experimental conditions, the detection limits for Cd(II), Co(II), and Ni(II) ions were found to be 0.13, 0.67, and 0.46 μg L−1, respectively, and the relative standard deviations for the analyte ions were found to be lower than 4.0%. The accuracy of the method was tested by analyzing certified reference material and spike tests. The method was applied to determine the levels of Cd(II), Co(II), and Ni(II) ions in sea and stream water, macaroni, red lentil, and cracked wheat samples.
AtıfScopus17WoS16OpenAlex16İncele - MakaleAçık Erişim2015Scopus SJRQ1Effect of onboard PM position on the magnetic force and stiffness performance of multi-seeded YBCO
Ozturk, K.; Kabaer, M.; Abdioglu, M.
Abstract In implemented studies before, although some advancements have been achieved in improving on the levitation or guidance force efficiency of YBCOs separately, both of these forces could not been enhanced simultaneously. In our study, we investigated levitation, guidance force and magnetic stiffness properties of multi-seeded YBCO bulk depending on different position of onboard PM in different CHs above a Halbach PMG to obtain larger vertical load capability, stability and relating stiffness values at the same time. The levitation, guidance force and relating stiffness measurements were carried out between multi-seeded YBCO and Halbach PMG depending on the onboard PM positions and cooling heights after the magnetic flux distributions modelling of Halbach PMG with onboard PMs. In this paper, it has clearly seen that the levitation force and the vertical magnetic stiffness values increase in optimal onboard PM position, with negligible lose in guidance force and lateral magnetic stiffness values. It is inferred from this study that reasonable position of the onboard PM according to PMG, the cooling conditions and compatibility of YBCO-PMG arrangement in point of magnetic flux distribution are key parameters for efficiency of the load, guidance force and relating magnetic stiffness of Maglev systems. The results obtained in this study have a potential on improvement of HTS Maglev system electromagnetic force capability.
AtıfScopus19WoS18OpenAlex19İncele - MakaleAçık Erişim2015Scopus SJRQ1Positive periodic solutions of nonlinear differential equations system with nonstandard growth
Ayazoglu Mashiyev, Rabil; Avci, Mustafa
In this work, we study the existence of positive periodic solutions for a p(t)-Laplacian system.
AtıfScopus2WoS2OpenAlex2İncele - MakaleYalnız künye2015Scopus SJRQ2Optimum design of steel frames with semi-rigid connections and composite beams
Artar, Musa; Daloʇlu, Ayşe T.
In this paper, an optimization process using Genetic Algorithm (GA) that mimics biological processes is presented for optimum design of planar frames with semi-rigid connections by selecting suitable standard sections from a specified list taken from American Institute of Steel Construction (AISC). The stress constraints as indicated in AISC-LRFD (American Institute of Steel Construction - Load and Resistance Factor Design), maximum lateral displacement constraints and geometric constraints are considered for optimum design. Two different planar frames with semi-rigid connections taken from the literature are carried out first without considering concrete slab effects in finite element analyses and the results are compared with the ones available in literature. The same optimization procedures are then repeated for full and semi rigid planar frames with composite (steel and concrete) beams. A program is developed in MATLAB for all optimization procedures. Results obtained from this study proved that consideration of the contribution of the concrete on the behavior of the floor beams provides lighter planar frames.
AtıfScopus16WoS16OpenAlex9İncele