Sürdürülebilir Kalkınma Amaçları
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- Dertli, Enes(117)
- Kaya, Yunus(51)
- Şahin, Engin(48)
- İspirli, Hümeyra(47)
- Özen, Soner(46)
- Şenay, Volkan(45)
- Pat, Suat(44)
- Can, Zehra(39)
- Bayraktar, Bülent(37)
- Bayram, Sinan(37)
- Korkmaz, Şadan(36)
- Cuce, Erdem(35)
- Ecem Bayram, Nesrin(33)
- Kutlu, Naciye(33)
- Yilmaz, Mustafa Tahsin(32)
- Artar, Musa(31)
- Ertugrul, Mehmet(30)
- Öner, Erdal(30)
- Ayata, Ümit(29)
- Hasar, Ugur Cem(29)
- Esmer, Yusuf(28)
- Mercan, Emin(27)
- Cuce, Pinar Mert(26)
- Özdemir, Akın(25)
- Çolak, Murat(24)
- Bayram, Ozkan(23)
- Kamiloğlu, Aybike(23)
- Sert, Durmuş(22)
- Ayazoglu, Rabil(21)
- Abdioglu, Murat(20)
- Bayram, Nesrin Ecem(20)
- Kadakal, Mahir(20)
- Kara, Yakup(20)
- Kizil, Hamit Emre(20)
- Tozlu, Alperen(20)
- Birinci, Ahmet(19)
- Gerçek, Yusuf Can(19)
- Battal, Fetullah(18)
- Dirican, Ebubekir(18)
- Ergün, Mustafa(18)
Yayınlar
- MakaleYalnız künye2010Scopus SJRQ2Improvements on slope diffraction for multiple wedges
Tabakcioglu, Mehmet Baris; Kara, Ali
This article proposes an improved slope uniform theory of diffraction model for fast and more accurate field prediction for multiple wedge diffractions in the transition zone. The proposed method is based on the slope uniform theory of diffraction and the Fresnel zone concept, called the slope uniform theory of diffraction with convex hull. The article also provides simulation results for the comparison of the uniform theory of diffraction based algorithms with respect to the computation time and accuracy.
AtıfScopus23WoS19OpenAlex23
İncele - MakaleYalnız künye2010Scopus SJRQ1Photodimerizations of hydroxy- and benzoylated 4-azachalcones and quantum chemical investigation of the reactions
Yaşar, Ahmet; YaylI, Nuran; Usta, Asu; YaylI, Nurettin
Photodimerization reactions of compounds 4-6 gave four new cyclobutane-containing compounds (7-9) with full control over the stereochemistry at the four stereogenic centers. These new cyclobutane- containing compounds had β-truxinic (7a), δ-truxinic (7b and 9), and ε-truxillic (8) structures. However, o-, m-, and p-hydroxy 4-azachalcones (1-3) did not give photochemical cyclization products under any conditions (in solvent or in their solid or molten states). Experimental data suggested the possibility of frontier orbital control over stereochemical behavior, so some theoretical calculations were performed. Full geometrical optimization of compounds 1-9 was performed via DFT B3LYP/6-31+G**, and their electronic structures were also investigated. The geometries of the singlet and triplet states were initially optimized by density functional theory (DFT) and the configuration interaction singles (CIS) B3LYP/3-21 +G**level. An additional calculation was performed for the triplet state using the ground-state geometry. The possible photochemical dimerization products of compounds 7-9 (a-g) and the intrinsic reaction coordinates (IRCs) of the reactions of compounds 4-6 were calculated theoretically by the DFT/3-21+G**method. The configurations (reactant, transition state, product, and reaction pathway) corresponding to the stationary points (minima or saddle points) were determined. The intrinsic reaction coordinates were followed to verify the energy profiles that connect each TS to the appropriate local minimum. The dimeric products expected from the calculations coincided with the dimers produced experimentally.
AtıfScopus4WoS3OpenAlex2
İncele - MakaleYalnız künye2010Scopus SJRQ2The first occurrence of the mite family linotetranidae (Acari: Tetranychoidea) in Turkey: Linotetranus anatolicus n. sp
Doǧan, Salih; Dönel, Güldem; Ali Bal, Durmus; Sezek, Fatih
A new species Linotetranus anatolicus Doan and Donel, n. sp. collected from soil, litter, oak bark and moss is herein described and figured. This is the first time that the family Linotetranidae has been recorded from Turkey.
AtıfScopus5WoS4OpenAlex6İncele - MakaleAçık Erişim2010Scopus SJRQ1Thermodynamics and kinetic studies of biosorption of a basic dye from aqueous solution using green algae Ulothrix sp.
Doǧar, Çetin; Gürses, Ahmet; Açikyildiz, Metin; Özkan, Esra
This study addresses removal of a basic dye, methylene blue, from aqueous solutions by using dried Ulothrix sp. biomass as biosorbent. The effects of the initial dye concentration, contact time, temperature, solution equilibrium pH, biosorbent dosage, and mixing rate on biosorption of the dye have been investigated. It was found that 30 min is sufficient in order to reach adsorption equilibrium. The amount of methylene blue adsorbed onto Ulothrix sp. increased with increasing equilibrium pH and mixing rate, in contrary, it decreased with increasing temperature and sorbent dosage. The process followed the pseudo-second-order kinetic model. The isosteric enthalpy and entropy values were calculated as -11.8 kJ/mol and 37.5 J/(mol K), respectively. In addition, the results suggest that the physical interactions between sorbent particles and sorbate ions play an important role for the adsorption of methylene blue onto the biosorbent.
AtıfScopus80WoS74OpenAlex85İncele - MakaleAçık Erişim2010Scopus SJRQ3Customer risk perceptions of internet banking - A study in turkey
Demirdogen, Osman; Yaprakli, Şükrü; Yilmaz, Mustafa Kemal; Husain, Jamaluddin
Technological developments in electronics have lead to the introduction of technology-based self-service systems resulting in the reorganization of several industries offering their services in electronic format known as "e-service" - electorinic banking iscalled internet banking?. With increasingly easier access to the internet, even in developing countries like Turkey over 18 % of all banking customers already use Internet Banking actively. Customers usually perceive risks in conducting transactions electronically, and particularly if the transactions involve money. Risk perception can beof six different types: time risk, finacial risk, performance risk, psychological risk, safety risk & confidentiality risk. It is generally considered that risk perception could be higher for electronic banking services. This study aims to understand the extent to which this consideration is valid as well as to determine the levels of risk perception differences among those using Internet Banking and those not using it. A survey was conducted among 350 academic staffs andtheir responses were analyzed statistically. This study showed that while customers used Internet Banking for a variety of different purposes such as to determine account balance, transfer money, or to pay invoices, etc., there was a significant relationship between the income level of customers and their risk perceptions. An analysis of the differences in risk perceptions between bank customers using Internet Banking (IB) and those not using IB showed that risk perceptions in terms of financial, psychological and safety risks among customer not using IB was more pronounced than those using IB. Customers not preferring to use internet banking thought that they would be swindled when using this service, and therefore, were particularly careful about high risk expectation during money transfers from and between accounts.
AtıfScopus16OpenAlex27İncele - BildiriAçık Erişim2010The effect of PowerPoint presentations prepared and presented by prospective teachers on biology achievement and attitudes toward biology
Gürbüz, Hasan; Kişoǧlu, Mustafa; Erkol, Mehmet; Alaş, Ali; Kahraman, Sakip; Uzunboylu, H
The study aims to explore the effect of preparing and presenting powerpoint slides on prospective teachers' biology achievement and attitudes toward biology. The sample of the study was 109 freshman students from Pre-School Education Department at Atatürk University in Turkey. The sample was randomly assigned as control group consisted of 53 students and experimental group consisted of 56 students. The experimental group was taught by powerpoint presentations preparing and presenting by prospective teachers while the lesson was conducted through traditional approach in the control group. Results indicated that preparing and presenting powerpoint slides had a significant effect on prospective teachers biology achievement and attitudes towards biology.
AtıfScopus5WoS8OpenAlex19İncele - MakaleYalnız künye2010Scopus SJRQ2Complexation of metal ions with the novel diazadithia crown ether carrying two anthryl pendants in acetonitrile-tetrahydrofuran
Parlayan, Semanur; Başoǧlu, Aysel; Ocak, M.; Alp, Hakan; Kantekin, Halit; Ocak, Ümmühan
A new crown ether carrying two anthryl groups with nitrogen-sulfur donor atom was designed and synthesized by the reaction of the corresponding macrocyclic compound and 9-chloromethyl anthracene. The influence of metal cations such as Al3+, Zn2+, Fe2+, Fe3+, Co2+, Ni2+, Mn2+, Cu2+, Cd2+, Hg2+ and Pb2+ on the spectroscopic properties of the ligand was investigated in acetonitrile-tetrahydofuran solution (1/1) by means of absorption and emission spectrometry. Absorption spectra show isosbestic points in the spectrophotometric titration of Fe2+, Fe3+, Al3+, Cu2+ and Hg2+. The results of spectrophotometric titration experiments disclosed the complexation stoichiometry and complex stability constant of the novel ligand with Fe2+, Fe3+, Al3+, Cu2+and Hg2+cations. The presence of excess amounts of Al3+, Zn2+, Fe2+, Fe3+, Co2+, Ni2+, Mn2+, Cu2+, Cd2+, Hg2+ and Pb2+ cations caused an enhancement of anthryl fluorescence. The ligand showed good sensitivity for Zn2+ with respect to other metal cations with linear range and detection limit of 1. 4 × 10-7 to 4. 1 × 10-6 M and 1. 0 × 10-8 M respectively.
- MakaleYalnız künye2010Scopus SJRQ1Characterization of liquefaction susceptibility of sands by means of extreme void ratios and/or void ratio range
Yilmaz, Y.; Mollamahmutoglu, M.
The liquefaction susceptibility of various graded fine to medium saturated sands are evaluated by stress controlled cyclic triaxial laboratory tests. Cyclic triaxial tests are performed on reconstituted specimens having global relative density of 60%. In all cyclic triaxial tests, loading pattern is selected as a sinusoidal wave form with 1.0 Hz frequency and effective consolidation pressure is chosen as 100 kPa. Liquefaction resistance is defined as the required cyclic stress ratio causing initial liquefaction in 10 cycles during the cyclic triaxial test. The results are used to draw conclusions on the effect of the extreme void ratios and void ratio range on the liquefaction resistance of various graded sands.
AtıfScopus48WoS42OpenAlex44İncele - MakaleAçık Erişim2010Scopus SJRQ2Pre- and post-cyclic loading strength of silica-grouted sand
Mollamahmutoglu, M.; Yilmaz, Y.
The aim of this study is to investigate whether there is a loss in the strength of fine- to medium-grained colloidalsilica-grouted sand after cyclic loading. First, the rheological properties of colloidal silica grouts, such as gel time and viscosity, are studied. Then, appropriate colloidal silica grouts (saline solution/colloidal silica suspension ratios of 10%, 15%, 20% and 25% by weight) are selected. The selected colloidal silica grouts are then injected into fine- to medium-grained sand specimens prepared at an overall relative density of 50%. The strength of the grouted sand specimens is determined by unconfined compression tests. The effect of curing period on the strength of the grouted samples is also investigated. After performing cyclic loading tests on grouted sand specimens at different cyclic stress ratios (0, 0.13, 0.26 0.39 and 0.52), it is observed that none of the samples failed or was damaged, and that the colloidal silica grout provides fine- to medium-grained sand with a significant resistance to cyclic deformation. The samples are then subjected to unconfined compression tests, and the results show that the loss in the strength of colloidal-silica-grouted sand is insignificant.
AtıfScopus38WoS32OpenAlex34İncele - MakaleYalnız künye2010Scopus SJRQ4Production of a novel pectin lyase from Bacillus pumilus (P9), Purification and characterisation and fruit juice application
Nadaroǧlu, Hayrunnisa; Taşkin, Esen; Adigüzel, Ahmet; Güllüce, Medine; Demir, Nazan
Extracellular pectin lyase (EC 4.2.2.10) was produced by Bacillus pumilus (P9) in solid state fermentation. Pectin lyase enzyme was purified 36.36 fold by using DEAE-cellulose anion exchange column chromatography and characterized. Molecular weight of the enzyme was determined as 25 kDa by using Sephadex G-100 gel filtration chromatography. Purification of enzyme was controlled by SDS-PAGE. The optimum pH and temperature of enzyme was determined as pH 6.0 and 60oC, respectively. Pectin lyase was mostly stable at 40°C. Its' activity deceased in 50% for 1h at 60°C and 40% for 4 h at 50°C. Vmax and KM were calculated respectively as 0.298 mg/mL and 132.6 mol/L*min. The presence of 10 mM concentration of Ca2+, Cu2+, Mn2+, Mg2+, Zn2+, Hg2+, Fe2+ and EDTA, L-cystein, ascorbic acid and -mercaptoethanol significantly enhanced the pectin lyase of the purified enzyme. The purified pectin lyase enzyme was used for getting fruits juices. It was determined that yields of fruits juices significantly improved when it was compared with control.
AtıfScopus33İncele - BildiriYalnız künye2009Scopus SJRQ1Screening of Three Exons of the RET Proto-oncogene in Turkish Patients with Papillary Thyroid Carcinoma
Bayramci, N. S.; Acik, L.; Koc, L. Y.; Vural, G.; Kilic, M.; Tez, M.; Koc, M.; Ercakmak, N.
- MakaleYalnız künye2009Scopus SJRQ3Purification and properties of carbonic anhydrase from bone marrow
Tasgin, Esen; Nadaroglu, Hayrunnisa; Demir, Yasar; Demir, Nazan
In this work, the carbonic anhydrase was purified from bovine bone marrow and investigated its kinetic properties. Carbonic anhydrase was purified from bovine bone marrow using affinity chromatography by sepharose 4B-L-tyrosine sulphanilamide. During purification steps, the activity of enzyme was measured using p-nitrophenyl acetate at pH: 7.4. Optimum pH and optimum temperature values for bovine bone marrow carbonic anhydrase were determined and then K m and Vmax values for the same substrate were obtained by means of Linewearver-Burk graphics. The purification degree for bovine bone marrow was calculated. The Vmax, and Km values at optimum pH and at 20 °C for the substrate (p-nitrophenyl acetate) were 120.418 uμmol/L min and 2.409 x 103 mM, respectively. The K1 and I50 values for sulfanilamide, KSCN, NaN3 and acetazolamide were determined in bovine bone marrow carbonic anhydrase.
AtıfScopus7İncele - MakaleYalnız künye2009Scopus SJRQ2First year Turkish science undergraduates' understandings and misconceptions of light
Yalcin, Mehmet; Altun, Sema; Turgut, Umit; Aggül, Fatma
The present study aims to identify first year Turkish Science undergraduates' understandings and misconceptions of the concept of light and its propagation. For this purpose, an instrument composed of four open-ended questions was developed by the researchers. The diagnostic test was piloted with twenty students and modifications were made prior to the final administration of the test. The content validity of the test questions was assessed by two physics researchers and one lecturer. These questions were administered to a hundred first year undergraduates (aged 16-18) enrolled in the Science Teacher Training Department in Ataturk University in Turkey. In addition, the semi-structured interviews of 30-40 min were conducted with the four students whose responses involved common misunderstanding. All interview records were transcribed and analysed. The findings showed that undergraduates' understanding of light is poor and also they have important and prevalent misconceptions. Identified misconceptions, some of which have been reported in the literature, are discussed qualitatively. The misunderstandings identified were compared with those in the literature. The results have some implications for teaching light, suggesting that a substantial revision of teaching strategies is needed.
AtıfScopus18OpenAlex24İncele - MakaleAçık Erişim2009Scopus SJRQ3The first occurrence of the uncommon family barbutiidae (Acari: Actinedida) in Turkey: Barbutia anguineus (Berlese)
Doǧan, Salih; Dönel, Güldem
A newly recorded mite species, Barbutia anguineus (Berlese), collected from Turkey is herein re-described and figured. This is the first record of the family Barbutiidae in Turkey.
AtıfScopus4WoS3OpenAlex3İncele - BildiriYalnız künye2009Investigation of the effect of a polypropylene fiber material on the shear strength and CBR characteristics of high plasticity Ankara clay
Mollamahmutoglu, M.; Yilmaz, Y.
Nowadays, many soil improvement methods have evolved with different materials used. In this study, a series of laboratory tests are carried out to investigate the effect of a polypropylene fiber material on the shear strength and California Bearing Capacity (CBR) characteristics of high plasticity Ankara clay. First, geotechnical properties of Ankara clay are presented. Then, results of unconfined compressive strength, triaxial strength (CU type) and CBR tests conducted on the various polypropylene fiber/clay mixtures (0.1%, 0.2%, 0.3% and 0.4% by dry weight) are given. Samples were compacted at optimum moisture contents and maximum dry unit weights obtained from the standard Proctor compaction effort. Standard Proctor compaction tests and CBR tests revealed that percentage of 19 mm length F type polypropylene fiber did not influence much the optimum moisture content, maximum dry unit weight and CBR values. Unconfined compression tests showed that inclusion of fiber content increased the axial strain at failure. Moreover, consolidated-undrained (CU) triaxial test results exhibited that due to inclusion of 19 mm length F type polypropylene fiber, the cohesion intercept decreased slightly but the internal angle of friction increased considerably.
AtıfScopus2İncele - MakaleAçık Erişim2009Scopus SJRQ3Synthesis of two alnustone-like natural diarylheptanoids via 4+3 strategy
Burmaoǧlu, Serdar; Çelik, Hülya; Göiksu, Süleyman; Maraş, Ahmet; Altundaş, Ramazan; Seçen, Hasan
The first total synthesis of (4E,6E)-1,7-bis(3,4-dihydroxyphenyl)-hepta-4, 6-dien-3-one and an alternative synthesis of (4E,6E)-1,7-bis(4-hydroxyphenyl)- hepta-4,6-dien-3-one, two natural diarylheptanoids, mainly based on Claisen-Schmidt condensation were described. The crucial steps of the syntheses were the condensation of OH-protected 4-aryl-2-butanones with OH-protected 3-aryl-acrylaldehydes by the in situ enamination and then deprotection of OH groups to give the corresponding natural diarylheptanoids.
AtıfScopus6WoS5OpenAlex7İncele - MakaleYalnız künye2008Investigation of effectiveness of demonstrationsimulation based instruction in teaching energy conservation at 7th grade
Aggul, Fatma; Yalcin, Mehmet; Acikyildiz, Metin; Sonmez, Erdal
This study aimed to explore the effect of teaching through demonstrationsimulation on students' achievement of energy conservation in comparison with traditional teaching. The sample consisted of fifty nine 7th grade students from a state primary school in Turkey. In the study, non-equivalent groups pretest-posttest design was used and the data was collected through an achievement test developed by the researchers, Energy Conservation Test. The conservation of energy concept was taught using a demonstration and a simulation in the experimental group and traditional instruction method in the control group. Data collected by the test was statistically assessed applying the analysis of covariance. To explore obviously the class atmosphere in experimental group, it was utilized from the teacher's observation notes and student interviews. The statistical comparison showed that there was a significant difference between groups with respect to students' scores of the test. Moreover, the analysis of the qualitative data indicated that such a class atmosphere supported the constructive and meaningful learning.
AtıfScopus6İncele - MakaleAçık Erişim2008Scopus SJRQ1Comparing the impacts of tutorial and edutainment software programs on students' achievements, misconceptions, and attitudes towards biology
Kara, Yilmaz; Yeşilyurt, Selami
The purpose of this study was to investigate the effects of tutorial and edutainment design of instructional software programs related to the "cell division" topic on student achievements, misconceptions and attitudes. An experimental research design including the cell division achievement test (CAT), the cell division concept test (CCT) and biology attitude scale (BAS) was applied at the beginning and at the end of the research. After the treatment, general achievement in CAT increased in favor of experimental groups. Instructional software programs also had the positive effect to the awareness of students' understandings to the general functions of mitosis and meiosis. However, the current study revealed that there were still some misconceptions in the experimental groups even after the treatment. It was also noticed that only using edutainment software program significantly changed students' attitudes towards biology.
AtıfScopus31OpenAlex51İncele - MakaleAçık Erişim2008Endurance training attenuates the oxidative stress due to acute exhaustive exercise in rat liver
Taysi, S.; Oztasan, N.; Efe, H.; Polat, M.F.; Gumustekin, K.; Siktar, E.; Canakci, E.; Akcay, F.; Dane, S.; Gul, M.
The aim of this study was to investigate whether an 8-week treadmill training attenuates exerciseinduced oxidative stress in rat liver. Male rats were divided into untrained and trained groups. Endurance training consisted of treadmill running at a speed of 2.1 km/h, 1.5 h/day, 5 days a week for 8 weeks. To see the effects of endurance training on acute exhaustive exercise induced oxidative stress, untrained and trained rats were further devided into two groups: animals killed at rest and those killed after acute exhaustive exercise, in which the rats run at 2.1 km/h (10% uphill) until exhaustion. Acute exhaustive exercise increased malondialdehyde level in untrained but not in trained rats. It decreased the activity of glutathione peroxidase and total (enzymatic plus non-enzymatic) superoxide scavenger activity in untrained rats and catalase activity in trained rats. However, it did not affect glutathione S-transferase, glutathione reductase, superoxide dismutase and non-enzymatic superoxide radical scavenger activities in both trained and untrained rats. On the other hand, endurance training decreased glutathione peroxidase and glutathione S-transferase activities. The results suggested that endurance training attenuated exercise-induced oxidative stress in liver, probably by preventing the decreases in glutathione peroxidase and total superoxide scavenger activities during exercise.
AtıfScopus30OpenAlex31İncele - MakaleYalnız künye2008Scopus SJRQ1The removal of lignin and phenol from paper mill effluents by electrocoagulation
Uǧurlu, M.; Gürses, A.; Doǧar, Ç.; Yalçin, M.
This study aims to investigate the treatment of paper mill effluents using electrocoagulation. Removal of lignin, phenol, chemical oxygen demand (COD) and biological oxygen demand (BOD) from paper mill effluents was investigated at various current intensities by using different electrodes (Al and Fe) and at various electrolysis times (1.0, 2.5, 5.0 and 7.5 min). It was observed that the experiments carried out at 12 V, an electrolysis time of 2 min and a current intensity of 77.13 mA were sufficient for the removal of these pollutants with each electrode. The removal capacities of the process using an Al electrode were 80% of lignin, 98% of phenol, 70% of BOD, and 75% of COD after 7.5 min. Using an Fe electrode the removal capacities were 92%, 93%, 80% and 55%, respectively. In addition, it was found that removal of lignin, phenol, BOD and COD increased with increasing current intensity. In the experiments carried out at different current intensities, higher removal can be explained through a decrease in intra-resistance of solution and consequently an increase at the transfer speed of organic species to electrodes. It was also found that Al electrode performs higher efficiency than Fe electrode except for COD removal. However, the time required for removal of BOD was more than that of COD. The results suggest that electrocoagulation could be considered as an effective alternative to paper mill effluents treatment.
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