Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Pat, Suat(15)
- Özen, Soner(15)
- Korkmaz, Şadan(11)
- Şenay, Volkan(10)
- Dertli, Enes(7)
- Kahya, Cem(6)
- Artar, Musa(5)
- Eroğlu, Yüksel(5)
- Senay, Volkan(5)
- Agar, Guleray(4)
- Demirtas, M.(4)
- Kizil, Hamit Emre(4)
- Korkmaz, Sadan(4)
- Purcek, G.(4)
- Tosun, Figen Çam(4)
- Yanar, H.(4)
- Abdioglu, M.(3)
- Anar, Mustafa(3)
- Ayberkin, Doruk(3)
- Aydin, Nevzat(3)
- Barroso, Joaquim José(3)
- Başar, Enes Emre(3)
- Cinar, Mehmet(3)
- Daloʇlu, Ayşe T.(3)
- Ertugrul, Mehmet(3)
- Kaplan, Abdullah(3)
- Kaya, Yunus(3)
- Ozturk, K.(3)
- Peker, Adem(3)
- Yılmaz, Gül Kalelı(3)
- Zhang, Z.F.(3)
- Zhang, Z.J.(3)
- İlter, İlhan(3)
- Aktepe, Evrim(2)
- Alpsoy, Lokman(2)
- Altuntas, Serkan(2)
- Asiri, Abdullah M.(2)
- Başoʇlu, Aysel(2)
- Beydemir, Şükrü(2)
- Birinci, Ahmet(2)
Yayınlar
- BildiriAçık Erişim2015Scopus SJRQ3Investigation of an alternative fuel for diesel engines
Keven, A.; Karaali, R.
Internal combustion engines use generally fossil fuel products. World resources of it is limited. Renewable alternative energy sources are getting important solution for energy demand. Hazelnut oil ethyl ester is obtained from raw hazelnut and mixed with diesel oil in certain proportions to use in a four-stroke direct injected single cylinder diesel engine. In this study the effects of the mixture of diesel oil with hazelnut oil ethyl ester on the engine performance and exhaust gas emissions are investigated for the first time in literature. The fuel injection system is regulated to use the mixture in the engine for the investigation. The results show that, the mixture with 25% ethyl ester extracted from hazelnut oil can be used as an alternative fuel without any change or regulation of the diesel engine.
AtıfScopus7WoS3OpenAlex7
İncele - MakaleYalnız künye2015Scopus SJRQ1Effect of equal-channel angular pressing on room temperature superplasticity of quasi-single phase Zn-0.3Al alloy
Demirtas, M.; Purcek, G.; Yanar, H.; Zhang, Z.J.; Zhang, Z.F.
Quasi-single phase (dilute) Zn-0.3Al alloy was subjected to severe plastic deformation via equal-channel angular extrusion/pressing (ECAE/P), and the effects of ECAP on its room temperature (RT) and high strain rate (HSR) superplasticity and deformation mechanism were investigated. Multi-pass ECAP may refine the coarse-grained microstructure into the fine grained (FG) one. The grain size of Zn-matrix phase decreased down to 2.0m after ECAP. Many spherical Al-rich precipitates decomposed and homogeneously distributed inside the matrix phase. They are ultrafine grained (UFG) α-particles with the grain sizes ranging from 50nm to ~200nm. This special microstructure having FG and UFG micro-constituents brought about an improvement in RT superplasticity even at HSRs. While multi-pass ECAP decreased flow stress of the alloy, its elongation to failure increased substantially depending on the initial strain rates. The maximum elongation was 1000% at a low strain rate of 10-4s-1, and 350% elongation was achieved at a high strain rate of 10-2s-1. Grain boundary sliding (GBS) was found to be the main deformation mechanism in region-II as the optimum superplastic region.
AtıfScopus60WoS59OpenAlex55İncele - MakaleAçık Erişim2015Scopus SJRQ3Writing and its use as a learning tool from teachers’ perspective: Instrument development and a pilot implementation; [Öğretmen Perspektifinden Yazma ve Yazmanın Öğrenme Amaçlı Kullanımı: Ölçme Envanteri Geliştirme ve Pilot Uygulama]
Ozturk, Bilge; Gunel, Murat
The aim of this study is to develop a measurement instrument to investigate science teachers’ perceptions toward writing and the use of writing as learning strategies in their learning environments. Aligned with the focus of the study, a Likert-type survey was developed through the previously developed international scale adaptation and literature review process. Using quantitative methodology and descriptive research method, the scale was implemented to 131 science teachers working at public schools in Erzurum, Turkey during 2011- 2012 school year. The data was analyzed through descriptive statistics for each item in the survey. The findings of the study revealed that science teachers perceive writing as a learning tool. Indeed, they believe that writing serves as a learning tool both for themselves and for their students. Further results revealed that teachers are aware of the significance of the writing in the development of students’ literacy skills. However, their in-class practices are limited in terms of implementing writing activities as a learning tool.
AtıfScopus2OpenAlex5İncele - MakaleYalnız künye2015Scopus SJRQ3Determination of antigenotoxic effects of four lichen species by using human lymphocytes
Anar, Mustafa; Asian, Ali; Ceker, Selcuk; Kizil, Hamit Emre; Alpsoy, Lokman; Agar, Guleray
In this study, the geno-toxic and antigeno-toxic properties of the total extracts of four lichen species were investigated by using human lymphocytes. We obtained total extracts from R farinacea, X. parietina, U. articulataand U. filipendula lichen species. The results of our studies showed that 5 μM concentrations of AFB1 changed the frequencies of micronucleus (MN) and malondialdehyde (MDA) levels, as well as superoxide dismutase (SOD), glutathione (GSH) and glutathione peroxidase (GPx) activities. When 5,10 and 20 μg/ml concentrations of total extract were added to AFB1, the frequencies of MN and MDA levels were decreased, and SOD, GSH and GPx levels were increased. Consequently, our findings show that four lichen total extracts have strong antigenotoxic properties against aflatoxin Bi.
AtıfScopus3İncele - MakaleYalnız künye2015Scopus SJRQ1Simple time-saving method for iron determination based on fluorescence quenching of an azaflavanon-3-ol compound
Başoʇlu, Aysel; Tosun, Gonca; Ocak, Miraç; Alp, Hakan; Yayli, Nurettin; Ocak, Ümmühan
A simple and time-saving spectrofluorometric method developed using an azaflavanon-3-ol compound was used for the determination of iron in various food samples. Nitric acid and hydrogen peroxide were used for digestion of samples in a closed microwave system. The method was validated by analyzing two certified reference materials (CRM-SA-C Sandy Soil C and Mixed Polish Herbs INCT-MPH-2). Measurements were carried out using a modified standard addition method. The standard addition graph was linear until 21.6 mg/L in the determination of iron(III). Detection and quantification limits were 0.81 and 2.4 mg/L, respectively. Satisfactory accuracy was obtained for spinach, dill, mint, purslane, rocket, red lentils, dry beans, and two iron medicinal tablets. High recoveries were found for streamwater samples fortified at three different concentrations. The method is simple, time-saving, cost-effective, and suitable for the determination of the iron content of foods.
AtıfScopus22WoS19OpenAlex21
İncele - MakaleYalnız künye2015Scopus SJRQ2Structure'activity relationships and quantitative structure'activity relationships modeling of some 3-(aryl)-N-(aryl)-1,2,4-Oxadiazol-5-Amine derivatives as anti-proliferative agents
Belaidi, Salah; Kerassa, Aicha; Lanez, Touhami; Cinar, Mehmet
Quantitative structure activity relationship studies were performed on a series of 3-(aryl)-N-(aryl)- 1,2,4-oxadiazol-5-amines as anti-proliferative agents, multiple linear regression analysis was performed to derive quantitative structure activity relationship models which were further evaluated internally for the prediction of activity. The developed models were cross-validated by the 'leave one out' technique as well as by the calculation of statistical parameters. The best QSAR model i.e., model-2 (R2 = 0 906, Fischer's test value F = 12066) has acceptable statistical quality and predictive potential as indicated by the value of cross validated squared correlation coefficient (q2 = 0 907). The present investigation indicates the importance of the quantum chemical descriptors, constitutional descriptors and hydrophobicity to study the anti-proliferative activity.
AtıfScopus7WoS4OpenAlex2İncele - MakaleAçık Erişim2015Scopus SJRQ2Analysis of continuous and discontinuous cases of a contact problem using analytical method and FEM
Birinci, Ahmet; Adıyaman, Gökhan; Yaylacı, Murat; Öner, Erdal
In this paper, continuous and discontinuous cases of a contact problem for two elastic layers supported by a Winkler foundation are analyzed using both analytical method and finite element method. In the analyses, it is assumed that all surfaces are frictionless, and only compressive normal tractions can be transmitted through the contact areas. Moreover, body forces are taken into consideration only for layers. Firstly, the problem is solved analytically using theory of elasticity and integral transform techniques. Then, the finite element analysis of the problem is carried out using ANSYS software program. Initial separation distances between layers for continuous contact case and the size of the separation areas for discontinuous contact case are obtained for various dimensionless quantities using both solutions. In addition, the normalized contact pressure distributions are calculated for both cases. The analytic results are verified by comparison with finite element results. Finally, conclusions are presented.
AtıfScopus38WoS39OpenAlex36İncele - MakaleYalnız künye2015Scopus SJRQ3The effect of concept cartoons to academic achievement in instruction on the topics of divisibility
Kaplan, Abdullah; Öztürk, Mesut
The purpose of this study was compared to the effect of academic achievement of concept cartoons and activity based instruction in instruction on the topics of divisibility rules and prime number. The matching- only design, which is quasi experimental design, is used in this study. It is applied sixth grade (N=42) students at a middle school in Gümüşhane in autumn term in academic year 2012- 2013. Different two groups participate for this study. One of the groups is selected control group, which is used activity based teaching, and another group is experimental group, which is used instruction by concept cartoon. SPSS 16.0 packet program is used in the analysis of the data in this study. The first the test of the normality, within pretest and posttest, is applied and was founded that the data is suitable the normality. Then t- test is applied between pretest data for reveal whether different significant or not. ANCOVA is applied covariate pretest results to post test data. The study reveal that there was a significant difference in academic achievement between those students taught with the two methods in favor of concept cartoon which means those students taught by concept cartoon performed better than those taught with activity based instruction. The finding also shows that concept cartoon method is an effective method of teaching topics of divisibility rules and prime numbers.
AtıfScopus4İncele - MakaleYalnız künye2015Scopus SJRQ3Optical and surface properties of LiFePO4 thin films prepared by RF magnetron sputtering
Volkan, Şenay; Özen, Soner; Pat, Suat; Korkmaz, Şadan
LiFePO4 thin films with thickness values of 65 nm and 70 nm were deposited onto glass substrates by RF magnetron sputtering, using a LiFePO4 target in the argon atmosphere. A comprehensive study of the optical properties was performed and the dispersions of the constants were determined. The transmittance and absorbance spectra were measured in the wavelength range of 400-1000 nm. The films showed optical transmittance over 90% in the visible range. The optical band gap value of the films was evaluated as 3 eV. The refractive index value of the films is 1.63 at λ = 550 nm. AFM micrographs indicate smooth surface with low values ofroot mean square roughness. Contact angle measurements of several testing liquids were used to characterize each sample in terms of wettability. The films are hydrophilic as observed from contact angle measurements. The surface free energy of the film surfaces and their components (dispersive and polar) were calculated from the contact angle data using the different theories available in the literature.
AtıfScopus14WoS12OpenAlex15İncele - MakaleAçık Erişim2015Scopus SJRQ1A new frost salt scaling mechanism for concrete pavements based on brine rejection from ice layer adhered to concrete surface
Yener, Engin
In cold regions, highways, airfields or sidewalks are exposed to de-icing agents to thaw the ice layer on pavement surface. In this situation, a progressive surface damage that pulls off flaky chips from concrete pavement takes place. This damage is named as frost salt scaling. To produce scaling-resistant concrete and prevent the damage in the field, the deterioration mechanism should be understood well. For this aim, a number of mechanisms have been hypothesised in literature. However, there is no unique one which can be used to explain all observations from laboratory tests and field applications. In this study, a novel hypothesis that is built on earlier findings in literature is introduced. According to the proposed mechanism, the pressure applied by forced brine from outer strong ice layer, which adhered to surface, causes scaling in the strongly ice adhered regions. The published events that are unexplainable by a unique former mechanisms proposed in literature related to the frost scaling are rationalised based on the proposed mechanism.
AtıfScopus16WoS13OpenAlex25İncele - MakaleAçık Erişim2015Scopus SJRQ1Asymmetric Friedel-Crafts alkylation of pyrrole with nitroalkenes catalyzed by a copper complex of a bisphenol A-derived Schiff base
Özdemir, Halide Sedef; Şahin, Engin; Çakici, Murat; Kiliç, Hamdullah
The asymmetric Friedel-Crafts (FC) alkylation of pyrrole with nitroalkenes was mediated by CuBr2 and a novel bisphenol A-derived chiral catalyst at room temperature. The catalyst was found to be applicable for the asymmetric FC alkylation of pyrrole with a wide range of nitroalkenes, affording optically active alkylated pyrroles with enantioselectivities up to 94%. Furthermore, enantiomerically pure 3-nitro-2-arylpropanamides were prepared by the oxidative cleavage of the pyrrole rings in the FC products with NaIO4/RuCl3 to demonstrate the synthetic application of the products.
AtıfScopus18WoS15OpenAlex17İncele - MakaleAçık Erişim2015Scopus SJRQ1Achieving room temperature superplasticity in Zn-5Al alloy at high strain rates by equal-channel angular extrusion
Demirtas, M.; Purcek, G.; Yanar, H.; Zhang, Z.J.; Zhang, Z.F.
Multi-pass equal-channel angular extrusion/pressing (ECAE/P) was applied to the eutectic Zn-5Al alloy to achieve high strain-rate (HSR) superplasticity in that alloy at room temperature (RT) by producing ultrafine-grained (UFG) microstructure. ECAE processing transformed the coarse-grained lamellar/spherical microstructure into a unique bimodal structure having equiaxed Zn-rich η-phase with a mean grain size of 540 nm and spherical Al-rich α-phase with an average grain size of 110 nm. The α-phase particles accumulated mainly along the η-phase boundaries. This unique microstructure brought about an extraordinary improvement in HSR superplasticity of the alloy even at RT. While the strength values decreased after ECAE, the elongation to failure increased substantially. The maximum elongation was 520% at the strain rate of 10-3 s-1, still high elongation of about 400% was achieved at a high strain rate of 10-2 s-1. This extraordinary improvement in HSR superplasticity of Zn-5Al alloy was attributed to the morphologically unique bimodal microstructure in UFG regime formed after ECAE. The grain boundary sliding (GBS) was found to be the main deformation mechanism for this alloy in superplastic regime.
AtıfScopus33WoS35OpenAlex34İncele - BildiriAçık Erişim2015Scopus SJRQ3Thermoeconomic analyses of steam injected gas turbine cogeneration cycles
Karaali, R.; Öztürk, I.T.
In this study, three different gas turbine cogeneration systems that are preheating air, preheating air-fuel and simple cycles where steam injected in to combustion chamber are analyzed. The effects of steam injection on thermoeconomic performance are calculated and obtained. By using the first law of thermodynamics, the exergy analysis and economic methods, simulation programs written by the authors in FORTRAN code are obtained to use for the analyses. Thermoeconomic performance of these three different cycles for different stage and variable mass of injected steam are obtained and compared with literature. The effects of injection steam in to combustion chambers of those three cycles for variable compressing ratios, on power, efficiencies, product price and performances are obtained. Consequently, the advantages and the disadvantages of injection steam are evaluated. The results obtained in this study are compared with the results available in the literature. Injection steam into combustion chamber increases the electricity efficiency and electricity power but decreases the heat power of the cycles. Also the produced electricity price for per kWh is increasing.
AtıfScopus15WoS12OpenAlex18İncele - BildiriAçık Erişim2015Scopus SJRQ3Soil stabilization with using waste materials against freezing thawing effect
Yilmaz, F.; Kamiloʇlu, H.A.; Şadoʇlu, E.
Freezing-thawing processes hapenning in seasonally cold climate cause deformation of soil in time of freezing and strength loss while thawing. Problems of ground frost heave and soil softening belong to the important factors, that could cause serious damage and financial loss. Bayburt tuff and tuffites known as Bayburt Stone mines, located around Bayburt, play important role on economy of the Bayburt city. As a result of researches in 2005 total of 2 535 700 tons proved reserve were determined several places in Bayburt. The goal of this study is proving, that deposits of Green Bayburt Stone wastes, created in the stone quarries during the stone processing, can be used as a stabilizing material. By recycling the waste material rejected stone was mixed with lime and used as a soil stabilizator against freezing-thawing effect. Prepared natural and stabilized soil samples were subjected to freezing-thawing cycles after curing for 28 days. After the freezing-thawing cycles, compressive strength of the samples was measured to investigate the influence of the additives on the freezing-thawing properties of soil samples. As a result of this study, it was determined that samples stabilized with Green Bayburt Stone mixtures have high freezing-thawing durability as compared to unstabilized samples. As a consequence, it was seen that those mixtures can be successfully used as an additive material to enhance the freezing-thawing effects of cohessive soils.
AtıfScopus25WoS23OpenAlex28İncele - MakaleAçık Erişim2015Scopus SJRQ1Using solar greenhouses in cold climates and evaluating optimum type according to sizing, position and location: A case study
Çakir, Uğur; Şahin, Erol
This study deals with a comparison among five common greenhouse types with regard to total solar radiation gaining rates in greenhouse using season under some assumptions. Additionally, possibility of using greenhouses in cold climate regions is investigated. We analyzed five greenhouse types and developed a script in MATLAB platform for the solar radiation availability. This model is applicable and suitable for other buildings and places on the world. Even-span, uneven-span, vinery, semicircular and elliptic types of greenhouses have been analyzed. A "k" value (ratio of length to width of greenhouse) and greenhouse azimuth angle (GAA) are described. Seven different floor area are assigned for each greenhouse type such as 50m2, 100m2, 150m2, 200m2, 250m2, 300m2 and 400m2, respectively. For each floor area, k value is assigned from 1 to 10. Each greenhouse is oriented in 90 different angles according to south facade. Seasonal total solar energy gaining rates is computed individually for all possible greenhouse types, area, k number and orientation. Then a comprehensive comparison is made to determine the optimal greenhouse. The results show that greenhouses are usable and suitable for using in cold climate regions to increase the productivity. In addition, the elliptic type is the optimum one in all analyzed types of greenhouses for Bayburt conditions for all floor areas. It is followed by uneven-span, even-span, semi-circular and vinery type of greenhouses respectively. Shape and type of the roof are main effective parameters on solar energy gaining rates of greenhouses. Elliptic greenhouse should be preferred on the band of the latitude of Bayburt, unless there is restrictive factor like sizing and terrain.
AtıfScopus93WoS77OpenAlex95İncele - MakaleAçık Erişim2015Scopus SJRQ2Deposition of a Mo doped GaN thin film on glass substrate by thermionic vacuum arc (TVA)
Özen, Soner; Şenay, Volkan; Pat, Suat; Korkmaz, Şadan
Current research presents a new deposition method for GaN thin films that produces in a very short production time for GaN-based solid-state applications. A Mo doped GaN thin film on a glass substrate was produced by thermionic vacuum arc (TVA) technique. The TVA technique is a novel non-reactive plasma technique. The optical properties were determined by Filmetrics F20 interferometer and UV–Vis double beam spectrophotometer. The surface morphology was analyzed using field emission scanning electron microscopy and atomic force microscopy. The mean thickness value was measured as 100 nm by Filmetrics interferometer. The crystalline structure of the produced thin film has a Wurtzite crystal structure (004) as obtained by X-ray diffraction. Hardness value was determined as 14 GPa with the Oliver–Pharr method. The obtained properties are consistent with the values reported in related literature. The findings indicate that the TVA method provides advantages for optical and industrial applications.
AtıfScopus20WoS20OpenAlex22İncele - MakaleYalnız künye2015Scopus SJRQ2Analytical solution of a contact problem and comparison with the results from FEM
Öner, Erdal; Yaylaci, Murat; Birinci, Ahmet
This paper presents a comparative study of analytical method and finite element method (FEM) for analysis of a continuous contact problem. The problem consists of two elastic layers loaded by means of a rigid circular punch and resting on semi-infinite plane. It is assumed that all surfaces are frictionless and only compressive normal tractions can be transmitted through the contact areas. Firstly, analytical solution of the problem is obtained by using theory of elasticity and integral transform techniques. Then, finite element model of the problem is constituted using ANSYS software and the two dimensional analysis of the problem is carried out. The contact stresses under rigid circular punch, the contact areas, normal stresses along the axis of symmetry are obtained for both solutions. The results show that contact stresses and the normal stresses obtained from finite element method (FEM) provide boundary conditions of the problem as well as analytical results. Also, the contact areas obtained from finite element method are very close to results obtained from analytical method; disagree by 0.03-1.61%. Finally, it can be said that there is a good agreement between two methods.
AtıfScopus84WoS84OpenAlex35İncele - MakaleAçık Erişim2015Scopus SJRQ1The effects of heat treatment on the synthesis of nickel ferrite (NiFe2O4) nanoparticles using the microwave assisted combustion method
Karcioʇlu Karakaş, Zeynep; Boncukcuoʇlu, Recep; Karakaş, Ibrahim Hakki; Ertuʇrul, Mehmet
NiFe2O4nanoparticles were synthesized using the microwave assisted combustion method based on metal nitrate salts and urea. To remain of organic matters and to stabilize the particles, samples were thermally treated at various temperatures from 300-800 °C. The prepared samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) thermogravimetric analysis (TGA) and vibrating sample magnetometry (VSM). The heat treated samples show the reflection planes of (111), (220), (222), (311), (400), (422), (511), and (440) which perfectly confirm to a cubic spinel phase of NiFe2O4and no secondary phases were detected in the XRD patterns of the samples. The crystallite sizes calculated using the Debye-Scherrer formula were found to increase with the heat treatment temperature, from about 4 nm at 300 °C-85 nm at 800 °C. EDX results verify that the compositional mass rations were relevant, as expected from the synthesis. The micrographs of SEM and TEM showed that all of the samples have nano-crystalline behavior and particles indication cubic shape. Magnetization measurements were obtained at room temperature by using a VSM, which demonstrated that the all of the samples synthesized with heat treatment exhibited ferromagnetic behaviors.
AtıfScopus96WoS86OpenAlex95İncele - MakaleAçık Erişim2015The effect of dynamic geometry software and physical manipulatives on candidate teachers’ transformational geometry success
Yılmaz, Gül Kaleli
This study aims to investigate the effects of using Dynamic Geometry Software (DGS) Cabri II Plus and physical manipulatives on the transformational geometry achievement of candidate teachers. In this study, the semiexperimental method was used, consisting of two experimental and one control groups. The samples of this study were 117 students. A 30-question test which was prepared based on the relative literature and expert opinion was used as a data collection tool. The test includes sections on recognition, features, and construction, and each section consists of ten questions. The data obtained from the pre- and post-tests were analyzed using the SPSS program. As a result of the statistical analysis, success levels of all groups were found to be the same before the applications, but after the applications, students’ transformational geometry success was found to significantly increase. When group success was analyzed, it was seen that the Computer Group placed first, the Manipulatives Group placed second, and the Traditional Group placed third in the sections of recognition and features. In the construction section, the Computer and Manipulatives Groups’ success levels were equal, and both groups were significantly more successful than the Traditional Group. The exercises performed with all groups increased their success levels significantly, thus showing that the applications were effective.
AtıfScopus7OpenAlex9İncele - MakaleYalnız künye2015Scopus SJRQ1A novel approach based on DEMATEL method and patent citation analysis for prioritizing a portfolio of investment projects
Altuntas, Serkan; Dereli, Türkay
The aim of this article is to propose a novel approach based on a method called Decision-Making Trial and Evaluation Laboratory (DEMATEL) and patent citation analysis for prioritizing the portfolio of investment projects. The proposed approach reflects the government's perspective and takes into account two important prioritization criteria. They are: (i) the decreasing rate of foreign trade deficits in the country and (ii) the potential to attract new investments which are not considered in the literature before. A case study from Turkey is presented to demonstrate the benefits of the proposed approach. The findings show that the proposed approach can be used easily and efficiently to prioritize investment projects among available project proposals.
AtıfScopus118WoS92İncele