Yayınlar
Koleksiyondaki öğeler
- MakaleAçık Erişim2015Relieving of misconceptions of derivative concept with derive
Kaplan, Abdullah; Ozturk, Mesut; Ocal, Mehmet Fatih
The purpose of this study is to determine students' learning levels in derivative subjects and their misconceptions. In addition, this study aims to compared to the effects of the computer based instruction and traditional instruction in resolving these misconceptions. For this purpose, 12th grade 70 students were chosen from high schools in Ağrı city with simple random sampling method. With the pre-test results, the misconceptions were determined and these misconceptions were tried to be relieving in two groups of students with computer based instruction and traditional instruction, separately. The result of the study showed that both the computer based instruction by using Derive software and traditional instruction methods were effective in resolving misconceptions that students constructed. However, it was found that the computer based instruction was more effective than traditional in relieving them.
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İncele - MakaleAçık Erişim2019Scopus SJRQ2Effects of artificial weathering on the surface properties of ultraviolet varnish applied to lemonwood (Citrus limon (L.) Burm.)
Ayata, Ümit
Ultraviolet varnishes are widely used for production processes in the parquet industry. A large number of chemicals are used in this sector, and each one has different characteristics. In this study, the effects of accelerated aging of ultraviolet varnish (3 and 5 coats) when applied to lemonwood (Citrus limon (L.) Burm.) (grown in Mezitli, Mersin, Turkey) were investigated. The ultraviolet varnish coated samples were subjected to aging processes (144 h, 288 h, and 432 h) by using UV-A 340 nm lamps. Color (L*, a*, b*, and ΔE*) parameters, glossiness (perpendicular (⊥) and parallel (//) at 20°, 60°, and 85°), and surface adhesion strength via the pull-off method for ultraviolet varnish coated samples were quantified before and after weathering. According to the results, the varnish type, aging period, and interaction between all studied variables, i.e. L*, a*, b* color parameters, glossiness (perpendicular (⊥) and parallel (//) at 20°, 60°, and 85°), and adhesion strength were found to alter the surface properties. As a result, the lemon tree can be used in the production of an ultraviolet parquet system.
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İncele - MakaleYalnız künye2016Scopus SJRQ3Renewable energy status and hydropower in some developing countries and focus on Turkey
Yuksel, Ibrahim; Arman, Hasan; Serencam, Ugur; Songur, Mehmet; Demirel, I. Halil
The share of renewable energies varies quite a lot in the developing countries, both in terms of total primary energy and electricity generation. Several different policy instruments are in use for promoting renewable energies, such as quota obligations, price subsidies, and taxes/tax exemptions on energy. Some countries such as Turkey, also have specific political programs for renewable energies. The obstacles and success conditions mainly deal with geographical, economic, administrative and political factors. The Republic of Turkey forms a natural bridge between Europe and Asia and the country has a relatively young population in both Europe and Asia. Turkey aims to utilize its energy potential, including from renewable sources, in a cost-effective manner. In its efforts to promote renewable energy, the government has focused on electricity, but has recently started to pay more attention to heat. On the other hand, Turkey's geographical location has several advantages for extensive use of most of the renewable energy sources. In this regard, renewable energy resources appear the most efficient and effective solutions for clean and sustainable energy development in Turkey. In addition to Turkey has a great hydropower, especially small hydropower potential. This paper deals with Turkey's renewable energy status in developing countries.
AtıfScopus1İncele - MakaleYalnız künye2016Scopus SJRQ2Optical and surface properties of optically transparent Li3PO4 solid electrolyte layer for transparent solid batteries
Pat, Suat; Özen, Soner; Şenay, Volkan; Korkmaz, Şadan
In this study, optical and surface properties of the optically transparent Li3PO4 solid electrolyte layer for transparent solid battery have been investigated for the first time. To determine the optical properties, transmittance, absorbance, reflection, refractive index spectra, and optical band gap were determined by UV-Vis spectrophotometer and optical interferometer. The surface property of the transparent Li3PO4 solid electrolyte was analyzed using atomic force microscopy. One another important parameter is contact angle (CA) surface free energy (SFE). CA and SFE were determined by optical tensiometer. These values probably are a most important parameter for polymer and hybrid battery performance. For the best performance, value of CA should be low. As a result, solid electrolyte layer is a highly transparent and it has a high wettability. SCANNING 38:317–321, 2016.
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İncele - 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.
AtıfScopus53WoS53OpenAlex57İncele - MakaleYalnız künye2016Scopus SJRQ1Optimization of strength, ductility and electrical conductivity of Cu-Cr-Zr alloy by combining multi-route ECAP and aging
Purcek, G.; Yanar, H.; Demirtas, M.; Alemdag, Y.; Shangina, D.V.; Dobatkin, S.V.
Properties of Cu-Cr-Zr alloy with ultrafine-grained (UFG) structure produced by equal-channel angular pressing (ECAP) via different routes have been investigated. Special attention was paid to the optimization of multi-functional structural, thermal, electrical and mechanical properties of the alloy by aging of UFG one. Multi-pass ECAP via different routes gives rise to the formation of a deformation-induced submicrocrystalline structure with the grain (subgrain) sizes in the range of 200-300. nm depending on applied routes which leads to high hardness and strength in the Cu-Cr-Zr alloy with reduced ductility. Amongst the applied routes, route-Bc was found to be the best processing path for achieving the lowest grain size, the highest hardness and strength. Aging of 8Bc-processed UFG samples increases the hardness and strength of Cu-Cr-Zr alloy while retaining an electrical conductivity comparable to that of aged coarse-grained (CG) one. A satisfactory electrical conductivity of 71%IACS without considerable loss of peak hardness was achieved after aging of 8Bc-processed UFG alloy at 425. °C for 240. min. The precipitation strengthened UFG alloy remains its stable behavior at elevated temperatures up to 450. °C.
AtıfScopus164WoS147OpenAlex151İncele - 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 - EditoryalAçık Erişim2013Preface of the "2nd symposium on metaheuristic and numerical analysis / engineering applications"
Nigdeli, Sinan Melih; Bekdaş, Gebrail; Toklu, Yusuf Cengiz; Altan, Şemsi Burhanettin
- MakaleYalnız künye2013Scopus SJRQ2Determination of structural, spectrometric and nonlinear optical features of 2-(4-hydroxyphenylazo)benzoic acid by experimental techniques and quantum chemical calculations
Cinar, Mehmet; Yildiz, Nihat; Karabacak, Mehmet; Kurt, Mustafa
The optimized geometrical structure, vibrational and electronic transitions, chemical shifts and nonlinear optical properties of 2-(4-hydroxyphenylazo)benzoic acid (HABA) compound were presented in this study. The ground state geometrical structure and vibrational wavenumbers were carried out by using density functional (DFT/B3LYP) method with 6-311++G(d,p) basis set. The vibrational spectra of title compound were recorded in solid state with FT-IR and FT-Raman spectrometry in the range of 4000-400 cm-1 and 4000-10 cm-1; respectively. The fundamental assignments were done on the basis of the recorded spectra and total energy distribution (TED) of the vibrational modes. The 1H and 13C NMR spectra were recorded in deuterated DMSO solution, and gauge-invariant atomic orbitals (GIAOs) method was used to predict the isotropic chemical shifts. The UV-Vis absorption spectra of the compound were observed in the range of 200-800 nm in ethanol, methanol and water solvents. To investigate the nonlinear optical properties, the polarizability, anisotropy of polarizability and molecular first hyperpolarizability were computed. A detailed description of spectroscopic behaviors of compound was given based on the comparison of experimental measurements and theoretical computations.
AtıfScopus19WoS19OpenAlex19İncele - 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 künye2018Scopus SJRQ4Partial Purification and Some Interesting Properties of Glutathione Peroxidase from Liver of Camel (Camelus dromedarius)
Chafik, Abdelbasset; Essamadi, Abdelkhalid; Çelik, Safinur Yildirim; Solak, Kübra; Mavi, Ahmet
Climate change and increasing temperatures are global concerns. Well adapted to desert life, the camel (Camelus dromedarius) lives most of its life under high environmental stress and represents an ideal model for studying desert adaptation among mammals. Glutathione peroxidase is the principal antioxidant defense system capable of protecting cells from oxidative stress. Glutathione Peroxidase from camel liver was purified (11.64-fold purification with 1.73% yield) and characterized The molecular weight of the enzyme was estimated to be about 69 kDa by gel filtration and 34 kDa by SDS-PAGE, implying dimeric structure of the protein. An optimum temperature of 47°C and an optimum pH of 7.8 were found. This enzyme is a typical SH-enzyme that is inhibited by D,L-dithiothreitol and β-mercaptoethanol and sensitive to bivalent cations. The enzyme had common specificity toward hydroperoxides and high specificity for reduced glutathione. The Km and Vmax values for hydrogen peroxide and reduced glutathione were 0.57 and 2.10 mM and 1.11 and 0.87 U/mg, respectively. The purified enzyme contained 16 ng of selenium per mg of protein. Our results show that the camel glutathione peroxidse exhibits properties different of those reported for other mammalian species. Lower molecular weight, homodimeric structure, higher optimum temperature, relatively low optimum pH, high affinity for hydrogen peroxide at low concentration of reduced glutathione and very low content of selenium could be explained by adaptation of the camel to living in the desert under intense environmental stress.
AtıfScopus12WoS9OpenAlex11İncele - MakaleAçık Erişim2019Scopus SJRQ3Genotypic identification of lactic acid bacteria in pastirma produced with different curing processes; [Farklı kürleme İşlemleri İle üretilen pastırmada laktik asit bakterilerinin genotipik İdentifikasyonu]
Çınar, Kübra; Fettahoğlu, Kübra; Kaban, Güzin
The lactic acid bacteria isolated from pastirma, produced under controlled conditions using two different curing temperatures (4°C or 10°C) and two different curing agents (150 mg/kg sodium nitrite or 300 mg/kg potassium nitrate), were subjected to genotypic (16S rRNA sequecing) identification. According to the identification results, 68 of 87 isolates (78.16%) was identified as Pediococcus pentosaceus. This species was followed by P. acidilactici (14.94%), Lactobacillus sakei (4.60%) and L. plantarum (2.30%), respectively. P. pentosaceus was dominant species in all curing applications (4°C/nitrate or nitrite or 10°C/nitrate or nitrite). Another species determined in all groups was P. acidilactici. While L. plantarum was only isolated from samples produced with nitrate (4°C or 10°C), L. sakei was isolated from samples produced with nitrite (4°C or 10°C). The effect of the curing agent on the biodiversity of lactic acid bacteria in pastirma was more effective than the curing temperature.
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İncele - MakaleAçık Erişim2017Scopus SJRQ2A new species of Hoplopholcus Kulczyński, 1908 (Araneae: Pholcidae) from the European part of Turkey
Demircan, Nurcan; Topçu, Aydın
A new species of Hoplopholcus Kulczyński, 1908 is described from caves in Tekirdağ and Kırklareli provinces of Turkey on the basis of both sexes. A morphological description and diagnosis are presented together with figures of the habitus and copulatory organs. http://www.zoobank.org/urn:lsid:zoobank.org:pub:12383325-FFC5-428C-8F3B-74D79C7ABB4E
AtıfScopus2WoS2OpenAlex1İncele - MakaleYayıncıda açık erişim2018Scopus SJRQ2Optimization of Adsorption Parameters for Ultra-Fine Calcite Using a Box-Behnken Experimental Design
Uçurum, Metin; Özdemir, Akln; Teke, Çaǧatay; Serencam, Hüseyin; Ipek, Mümtaz
Removal of heavy metals from wastewater is a significant issue because it prevents environmental-based concerns and impacts a large number of diseases and disorders. Many low-cost natural materials have been offered recently as possible precursors to commercial synthetic adsorbents. Ultra-fine calcite, one of these natural materials, has been investigated as a potential commercial adsorbent. Response surface designs are effective experimental techniques to investigate the heavy metal adsorption capacity of ultra-fine calcite. In the present study, one such response surface design, Box-Behnken, is used in order to optimize adsorption factors, such as pH level, initial metal concentration, stirring rate and adsorption time, and to determine the heavy metal capacity of this adsorbent. Our results show that the proposed methodology is an effective approach to optimizing the adsorption process and to maximize the heavy metal capacity.
AtıfScopus9WoS7OpenAlex12İncele - MakaleYalnız künye2013Scopus SJRQ3Purification and characterisation of laccase from lactarius volemus and its application in removal of phenolic compounds from fruit juice
Nadaroglu, Hayrunnisa; Tasgin, Esen
Laccases are multicopper oxidases (EC 1.10.3.2.), widely distributed in fungi, higher plants and bacteria. In this research, a laccase from Lactarius volemus (Russulaceae) was purified by 73.08 fold using precipitate of saturation (NH4)2SO4, DEAE-cellulose and Sephacryl S200. It was shown that purified enzyme was homogeneous in term of SDS-PAGE with molecular mass estimated of 30 kDa. The pH was optimal at 4.0, enzyme was stable at pH 3.0-5.0 and optimal temperature was at 50°C. Cu2+ and Fe2+ were activated to the purified laccase enzyme, and it was partially inhibited by 5 mM concentration of some metal salts and EDTA, urea, SDS, L-cysteine, dithioeritritol and β-mercaptoethanol. In addition, it was investigated whether the purified and characterized laccase enzyme would remove the phenolic compound of some fruit juices which are responsible for haze formation and browning during storage. Their application led to reduction of total phenolic compounds for apple, apricot, cherry and grape juice. As a result, the effect of these enzymatic treatments on total phenol content and clarity of the juice were evaluated using a central composite design. This laccase enzyme had potential application in food processing.
AtıfScopus18İncele - MakaleAçık Erişim2017Scopus SJRQ3Effects of origanum syriacum essential oil on blood parameters of broilers reared at high ambient heat
Tekce, E.; Gül, M.
The biochemical and hematological blood values of broilers fed under heat stress and that were administered Origanum syriacum (OS) essential oil were investigated in this study. In total, 400 male broilers (Ross-308; age, 1 day) were used for the period of 42-days of the study. The experiment included ten groups (n = 50/group; each group divided into five sub-groups): normal heat, 22°C: basal feed (BF)-positive control group (PC), BF + 100 ppm OS; BF + 300 ppm OS; BF + 600 ppm OS). Heat stress, 36°C: BF-positive control group (PC), BF + 100 ppm SOS; BF + 300 ppm OS; and BF + 600 ppm OS). Biochemical and hematological parameters were measured in blood collected into EDTA tubes. Total bilirubin, cholesterol, low-density cholesterol, Na+, Ca2+, and Mg2+ increased, whereas alanine aminotransferase, aspartate aminotransferase, creatine kinase (CK), CK-MB, urea, uric acid, Cl–, and K+ decreased (p<0.05); however, no changes were detected in the other hematological values.
AtıfScopus18WoS17OpenAlex17İncele - MakaleAçık Erişim2019Phenolic composition and antioxidant properties of anzer honey from black sea region of Turkey; [Türkiye'nin Karadeniz Bölgesinden Anzer Balinin Fenolik Bilesimi ve Antioksidan Özellikleri]
Malkoç, Meltem; Çakir, Hilal; Kara, Yakup; Can, Zehra; Kolayli, Sevgi
Anzer honey is produced on the Anzer plateau, known for its rich flora, in the Eastern Black Sea region of Turkey. It is well known across the world, and is believed to be of high medical value. This study is the first detailed research in which the polyphenolic profiles responsible for the bioactive properties of Anzer honey was determined, melissopalynological analysis was performed, and in which total phenolic contents (TPC), total flavonoid contents (TFC), and total antioxidant activities were identified. The ferric (III) reducing antioxidant power (FRAP) assay and 1,1-diphenyl-2- picrylhydrasil (DPPH) free radical scavenging test were used to determine antioxidant activity. The total mean phenolic content of Anzer honey was 26.92 GAE/100 g, and the total flavonoid content was 2.79 mgQE/100g. Anzer honeys' mean FRAP and DPPH values were 110.11 μmoLTrolox/100g and 49,12 mg/mL, respectively. The phenolic acids and flavonoids of Anzer honey were determined using highperformance liquid chromatography (HPLC). Of the 19 standard compounds used in the analysis, pinocembrin, hesperidin, chrysin, protocatechuic acid, p-coumaric acid, catechin, caffeic acid phenyl ester (CAPE), p-OH benzoic acid, and caffeic acid as major compounds, while myricetin, luteolin, rutin, resveratrol, epicatechin, t-cinnamic acid, ferulic acid, and gallic acid were identified as minor compounds. Daidzein and syringic acid were not detected. Based on these findings, Anzer is a flower honey noteworthy for the rich variety of its polyphenols.
AtıfScopus22OpenAlex26TR Dizin8İncele - BildiriYalnız künye2016Some physical properties of Co-doped GaAs thin films grown by thermionic vacuum arc
Şenay, Volkan; Özen, Soner; Pat, Suat; Korkmaz, Şadan; Mohammadigharehbagh, Reza
Cobalt doped GaAs thin films with the thickness of 100 nm and 200 nm were deposited on glass substrates by a thermionic vacuum arc system. The optical and surface properties were investigated as functions of the film thickness. The refractive index of the films decreased with the increasing thickness. A band gap value of 1.42 eV was obtained for the 100 nm film and 1.38 eV for the 200 nm film from the Tauc plots of (αhν)2 vs. hν. According to the results obtained from the AFM studies, the root mean square surface roughness of the films were nm and 3.13 nm for the 100 nm and 200 nm film, respectively.
AtıfScopus1WoS1OpenAlex1İncele - MakaleYalnız künye2018Scopus SJRQ2Normal neutrosophic multiple attribute decision making based on generalized prioritized aggregation operators
Şahin, Rıdvan
Normal neutrosophic set, which allows a combination of the normal fuzzy number and the neutrosophic number, is a powerful tool for handling the incompleteness, indeterminacy and inconsistency of evaluation information. Based on the opinion of prioritized aggregation operators developed to describe the prioritization relationships among several attributes, this paper investigates some prioritized aggregation operators for aggregating the normal neutrosophic information, such as normal neutrosophic prioritized weighted averaging operator and normal neutrosophic prioritized weighted geometric operator, and then extends these operators to the generalized prioritized weighted aggregation operators, including normal neutrosophic generalized prioritized weighted averaging operator and normal neutrosophic generalized prioritized weighted geometric operator, respectively. They can take into account the prioritization facts in the aggregated information. Moreover, some of their desirable properties are investigated in detail. A multiple attribute decision-making method is developed for solving a kind of problems in which the decision attributes have different priority level commonly and they take the form of normal neutrosophic numbers. Finally, an illustrative example based on the prioritization relationship over the evaluation data is given to depict the effectiveness and feasibility of the developed decision-making method, which are then compared to the existing approaches.
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