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Koleksiyondaki öğeler
- MakaleYalnız künye2011Scopus SJRQ1Modeling of triple concave friction pendulum bearings for seismic isolation of buildings
Yurdakul, Muhammet; Ates, Sevket
Seismic isolated building structures are examined in this study. The triple concave friction pendulum (TCFP) is used as a seismic isolation system which is easy to be manufactured and enduring more than traditional seismic isolation systems. In the TCFP, take advantage of weight which pendulum carrying and it's geometry in order to obtain desirable result of seismic isolation systems. These systems offer advantage to buildings which subject to severe earthquake. This is result of damping force of earthquake by means of their internal constructions, which consists of multiple surfaces. As the combinations of surfaces upon which sliding is occurring change, the stiffness and effective friction change accordingly. Additionally, the mentioned the TCFP is modeled as of a series arrangement of the three single concave friction pendulum (SCFP) bearings. A two dimensional- and eight- story of a building with and without isolation system are used in the time history analysis in order to investigate of the effectiveness of the seismic isolation systems on the buildings. Results are compared with each other to emphasize efficiency of the TCFP as a seismic isolation device against the other friction type isolation system like single and double concave surfaces. The values of the acceleration, floor displacement and isolator displacement obtained from the results by using different types of the isolation bearings are compared each other. As a result, the findings show that the TCFP bearings are more effective devices for isolation of the buildings against severe earthquakes.
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İncele - 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 - MakaleYalnız künye2010Scopus SJRQ2Complexation of metal ions with double-armed diazadithia lariat ether carrying anthracene moieties in acetonitrile-dioxane
Parlayan, Semanur; Başoğlu, Aysel; Göbel, Yasemin; Ocak, Miraç; Alp, Hakan; Kantekin, Halit; Ocak, Ümmühan
A new 14-membered crown ether with nitrogen-sulfur donor atom carrying two anthryl groups was designed and synthesized by the reaction of the corresponding macrocyclic compound and 9-(chloromethyl) anthracene. The influence of metal cations such as Al 3+ , Zn 2+ , Fe 2+ , Fe 3+ , Co 2+ , Ni 2+ , Mn 2+ , Cu 2+ , Cd 2+ , Hg 2+ and Pb 2+ on the spectroscopic properties of the ligand was investigated in acetonitrile-dioxane solution (1/1) by means of absorption and emission spectrometry. The results of spectrophotometric titration experiments disclosed the complexation stoichiometry and complex stability constant of the novel ligand with Fe 2+ , Fe 3+ , Al 3+ , Cd 2+ , Cu 2+ , Zn 2+ , Pb 2+ and Hg 2+ cations. Absorption spectra show isobestic points in the spectrophotometric titration of these cations. The presence of excess of Al 3+ , Zn 2+ , Fe 2+ , Fe 3+ , Co 2+ , Ni 2+ , Mn 2+ , Cu 2+ , Cd 2+ , Hg 2+ and Pb 2+ cations caused an enhancement of anthryl fluorescence. Especially, the enhancement in case of the interaction of Hg 2+ and Al 3+ cations with the ligand was pronounced.
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İncele - MakaleAçık Erişim2013Scopus SJRQ3Solid phase extraction of Cd(ii) and pb(ii) ions by a new carbothioamide derivative
Ozdes, Duygu; Duran, Celal; Bayrak, Hacer; Serencam, Huseyin; Basri Senturk, Hasan
An effective, simple, low cost and accurate sorption-spectrophotometric platform for the extractions and subsequent quantifications of Cd(II) and Pb(II) ions in food and environmental samples has been described in this dissertation. The separation and preconcentration of the analyte ions were accomplished by solid phase extraction method based on the adsorption of their N-(4-methylphenyl)-2-{[(4-phenyl-5-pyridin-4-yl-4H-1,2,4-triazol-3-yl)thio] acetyl} hydrazinecarbothioamide (MFPTAHK) complex on Amberlite XAD-8 resin in a mini column. The developed method was systematically investigated in different set of experimental parameters that influence the separation and preconcentration of Cd(II) and Pb(II) ions. The precision of the method was determined by reproducibility studies and expressed as relative standard deviations (RSD %) which were less than 4% for both analyte ions. The limits of detections (LODs) for Cd(II) and Pb(II) ions based on the three times the standard deviation of the blanks (N:10) were found to be 0. 31 ?g L-1 and 0. 86 ?g L-1, respectively. The developed SPE procedure was utilized for the simultaneous extraction and determinations of Cd(II) and Pb(II) ions levels in rice, cracked wheat and red lentil as food samples and various water samples.
AtıfScopus5WoS4OpenAlex5İncele - MakaleYalnız künye2012Scopus SJRQ1Adsorption of phenol from aqueous solution on a low-cost activated carbon produced from tea industry waste: Equilibrium, kinetic, and thermodynamic study
Gundogdu, Ali; Duran, Celal; Senturk, H. Basri; Soylak, Mustafa; Ozdes, Duygu; Serencam, Huseyin; Imamoglu, Mustafa
The ability of activated carbon which was produced by chemical activation using zinc chloride from tea industry wastes (TIWAC) to adsorb phenol molecules from aqueous solution was tested by equilibrium, kinetic, and thermodynamic parameters. Phenol adsorption on TIWAC took place with a high yield at pH values in the range 4 to 8. The optimum contact period was observed as 4.0 h and from the adsorption graphs plotted as a function of time; it was established that phenol adsorption on TIWAC conformed more to a pseudosecond-order kinetic model. Additionally, it was determined that the adsorption rate is controlled by intraparticle diffusion as well as film diffusion. It was established that phenol adsorption on TIWAC can be better defined by the Langmuir adsorption model and its adsorption capacity was 142.9 mg·g-1 from the linear Langmuir equation. Temperature had an adverse effect on adsorption yield, and hence, the adsorption process was exothermic in our case. Moreover, increasing electrolyte concentration in the medium has a positive effect on adsorption yield. From the data obtained, it was concluded that the removal of phenol from aqueous solution by TIWAC produced from tea industry wastes with a very low cost took place with an extremely high performance.
AtıfScopus228WoS212OpenAlex222İncele - 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 - BildiriYalnız künye2012Scopus SJRQ3Biosorption of CR (VI) onto pseudevernia furfuracea /aqueous solution interface
Gürses, Ahmet; Özkan, Esra; Doǧar, Çetin
This study addresses the removal of a heavy metal, Cr (VI), from aqueous solutions by using dried Psedeuvernia furforcea biomass as biosorbent. The effects of factors, such as the initial chromium concentration, contact time, temperature, biosorbent dosage and mixing rate on biosorption of the heavy metal was investigated. Furthermore, the fitting of adsorption data on Langmuir, Freundlich, BET, Temkin, Redlich-Peterson, Henderson, Smith, Halsey and Harkins-Jura adsorption isotherm models was investigated. In order to explain the metal-functional group binding mechanisms, FTIR analysis was carried out. The sorption equilibrium time was determined to be 8 hours. The amount of Cr (VI) adsorbed onto Psedeuvernia furforcea increased with increasing sorbent dosage and increasing temperature indicating endothermic nature of biosorption process. The results suggest that the physical interactions between sorbent particles and sórbate ions play an important role for the adsorption of Cr (VI) onto the biosorbent. It was found that the biosorption data of Cr (VI) by Psedeuvernia furforcea biomass were fit on the Freundlich adsorption isotherms at 293, 313, and 333K. From the experimental results, it can be concluded that Psedeuvernia furforcea can be used as an economical sorbent in the removal of these heavy metal ions.
- MakaleYalnız künye2012Scopus SJRQ2Forced convective two phase flow analysis in a circular tube equipped with twisted tapes
Omeroglu, Gokhan; Comakli, Omer; Karagoz, Sendogan; Manay, Eyuphan
In forced convection boiling systems, it is important to know the dynamic behavior for understanding and predicting the local and global stability of the system. Besides this, the instability phenomenon in the industrial processes in which two phase flow takes part becomes more of an issue. So, the mechanisms of instabilities and the ways of decreasing the stabilities are of interest of the researchers for a long time. In this study, the effects of pitch ratio, inlet temperature and the mass flow rate on two phase flow instabilities in a horizontal circular tube are investigated. The experiments are conducted under constant system pressure, and a constant heat input of 24 kW is applied to the outer surface of the circular test pipe having constant exit restriction. The results of two different pitch ratios are also compared with the smooth tube. For all investigated cases, the results are evaluated in terms of pressure drop type and density wave type oscillations. The time dependent measurements of top wall temperature, bottom wall temperature, inlet pressure and mass flow rate variations are also presented. The boundaries of the oscillations are found for both twisted tape and smooth channel. It is found that the unstable region of the flow extends while the distance between boundaries increases. It is observed that the system is more stable in the case of the lowest pitch ratio, and the increase of the pitch ratio causes system to be less stable. By the decrease of the inlet temperature, the single phase liquid region extends in the test tube and thus the system becomes more stable.
- 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 - MakaleAçık Erişim2011Scopus SJRQ2A new eyeless mite species of the genus Eustigmaeus Berlese (Acari: Stigmaeidae) from Turkey; [Türkiye'den Eustigmaeus Berlese (Acari: Stigmaeidae) cinsine ait gözsüz yeni bir akar türü]
Doǧan, Salih; Dönel, Güldem; Özçelik, Sezgin
A new eyeless mite species of the genus Eustigmaeus from Turkey, Eustigmaeus anophthalmus, is described and illustrated.
AtıfScopus27WoS27OpenAlex28İncele - MakaleYalnız künye2012Scopus SJRQ3The prediction of heat transfer and fluid characteristics for equilateral triangular bodies in tandem arrangement by artificial neural networks
Manay, Eyüphan; Güneş, Sibel; Akçadirci, Esra; Özceyhan, Veysel; Çakir, Ǔur; Çomakli, Ömer
The objective of this study is to investigate the effect of the spacing between equilateral dual triangular bodies symmetrically placed into the channel axis under steady state conditions on heat transfer and fluid characteristics by using artificial neural networks (ANN). The Back Propagation (BP) training algorithm was applied to train the model. The successful application proved that ANN model can be used for predicting the Nusselt number and skin friction coefficient as a convenient and effective method. The distribution of local Nusselt number, skin friction coefficient along the channel wall and overall enhancement ratio of all investigated cases are presented.
AtıfScopus5İncele - BildiriAçık Erişim2011The investigating pre-service teachers' learning styles with respect to the gender and grade level variables
Metin, Mustafa; Yilmaz, Gül Kaleli; Birişçi, Salih; Coşkun, Kerem
The aim of this study is to investigate pre-service teachers' learning styles in terms of gender and grade level variables. The study was carried out at spring semester of 2010. The sample of the study consisted of 347 pre-service teachers at the Department of Primary and Science Teacher Education in Faculty of Education at Artvin Çoruh University. "Kolb Learning Style Inventory" was used as a data collection tool. The data were analyzed by using frequency, percentage, means, standard deviation, independent samples t-test and one-way ANOVA. The results show that the dominant learning style among the students is accommodator and it is followed by convergent, divergent and assimilator learning style. There was not significantly difference between students' learning style and gender and between students' learning style and grade level.
AtıfScopus7WoS7OpenAlex16İncele - MakaleAçık Erişim2010Scopus SJRQ2Complexation of metal ions with the novel azathia crown ethers carrying anthracene pendant in acetonitrile-dichloromethane
Ocak, Ümmühan; Ocak, Miraç; Başoǧlu, Aysel; Parlayan, Semanur; Başaran, Dilek; Alp, Hakan; Kantekin, Halit
A series of crown ethers carrying an anthracene group with nitrogen-sulfur donor atom, which differ in having three, four and five sulfur atoms in the macrocycle 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 ligands was investigated in acetonitrile-dichloromethane (1:1) by means of absorption and emission spectrometry. Absorption spectra show isosbestic points in the spectrophotometric titration of Al3+, Zn2+, Fe2+, Fe3+, Cu2+, Hg2+ and Pb2+ the results of which disclosed the complexation compositions and complex stability constants of the novel ligands with these cations. The monoazapentathia crown ether showed sensitivity for Al3+ with linear range and detection limit of 2.6 × 10-6 M-2.6 × 10-5 M and 8.1 × 10-7 M, respectively.
AtıfScopus10WoS9OpenAlex10İncele - Derleme MakaleYalnız künye2010Scopus SJRQ1Energy production, consumption, policies and recent developments in Turkey
Toklu, E.; Güney, M.S.; Işik, M.; Comakli, O.; Kaygusuz, K.
Many factors to be appropriately addressed in moving towards energy sustainability in Turkey are examined. These include harnessing sustainable energy sources, utilizing sustainable energy carriers, increasing efficiency, reducing environmental impact and improving socioeconomic acceptability. The latter factor includes community involvement and social acceptability, economic affordability and equity, lifestyles, land use and aesthetics. On the other hand, Turkey, with its young population and growing energy demand per person, its fast growing urbanization, and its economic development, has been one of the fast growing power markets of the world for the last two decades. Turkey is heavily dependent on expensive imported energy resources that place a big burden on the economy and air pollution is becoming a great environmental concern in the country. In this regard, renewable energy resources appear to be the one of the most efficient and effective solutions for clean and sustainable energy development in Turkey. Turkey's geographical location has several advantages for extensive use of most of these renewable energy sources. This article presents a review of the potential and utilization of the energy sources in Turkey.
AtıfScopus79WoS68OpenAlex99İncele - MakaleAçık Erişim2010Scopus SJRQ2Complexation of metal ions with the novel diazadithia crown ethers carrying two pyrene pendants in acetonitrile-tetrahydrofuran
Ocak, Ümmühan; Ocak, Miraç; Başoǧlu, Aysel; Parlayan, Semanur; Alp, Hakan; Kantekin, Halit
Two crown ethers carrying pyrene side arms with nitrogen-sulfur donor atom were designed and synthesized by the reaction of the corresponding macrocyclic compounds and 1-bromomethyl-pyrene. 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 ligands was investigated in acetonitrile-tetrahydrofuran (1:1) by means of absorption and emission spectrometry. Absorption spectra show isosbestic points in the spectrophotometric titration of Al3+, Zn2+, Fe2+, Ni2+, Cu2+, and Pb2+ with 16-membered crown ether. Similar results were obtained for Al3+, Fe2+, Hg2+, Cu2+ and Pb2+ with 14-membered crown ether. The results of spectrophotometric titration experiments disclosed the complexation stoichiometry and complex stability constants of the novel ligands with these cations. According to spectrofluorimetric titration measurements the 14-membered diazadithia crown ether showed sensitivity for Pb2+ with linear range and detection limit of 1.3 × 10-6 to 5.2 × 10-5 M and 5.2 × 10-7 M, respectively. The 16-membered diazadithia crown ether showed sensitivity for Ni2+ with linear range and detection limit of 1.3 × 10-7 to 5.2 × 10-6 M and 4.1 × 10-8 M, respectively.
AtıfScopus9WoS8OpenAlex8İncele - MakaleYalnız künye2012Scopus SJRQ1Determination of the effect of volcanic pumice replacement on macro void development for blended cement mortars by computerized tomography
Tekin, Ilker; Birgul, Recep; Aruntas, Huseyin Yilmaz
In this study, the effect of volcanic pumice replacements with different ratios on the macro void development was observed using CT for a period of 100 days. The cured mortar specimens were imaged by X-ray CT on different days of the experiment. Utilizing Hounsfield Unit values as guides, void volumes and ratios were identified and measured by Matlab software. SEM images supported the X-ray CT results. It is shown that X-ray CT analysis is capable of assessing the development of macro voids in the mortar specimens.
AtıfScopus22WoS21OpenAlex20İncele - MakaleYalnız künye2009Misconceptions and alternative concepts in biology textbooks: Photosynthesis and respiration; [Ideas falsas y conceptos alternativos en libros de texto de biología: Fotosíntesis y respiración]
Kose, Esra Ozay; Pekel, Osman; Hasenekoglu, Ismet
Textbooks have a specific importance since they are used as the main instruction material. It is important to know that whether commonly used textbooks are adequate in terms of content and presentation. This study was performed to examine whether chapters on "photosynthesis" and "respiration" in the Biology-3 textbooks, that are used in secondary schools in Turkey are sufficient in terms of scientific content or not. We provide examples of the identified misconceptions along with their more acceptable alternatives. As a result, it was determined that biology-3 textbooks are insufficient in respect of scientific content. We recommend that biology-3 textbooks must be improved by correcting the scientific content.
AtıfScopus12İncele - MakaleAçık Erişim2011Scopus SJRQ2Determination of protein and gluten quality-related parameters of wheat flour using near-infrared reflectance spectroscopy (NIRS); [Yakın Kızılötesi Spektroskopisi (NIRS) kullanarak buǧday unlarının protein ve glutenle ilgili kalite parametrelerinin belirlenmesi]
Başlar, Mehmet; Ertugay, Mustafa Fatih
Wet chemistry analyses done for quality control purposes in wheat and flour processing are time-consuming. Near-infrared spectroscopy (NIRS) as an alternative technology to conventional methods allows us to obtain results in a few seconds. In this study, NIRS was used in the development of calibration models for protein, wet and dry gluten contents and Zeleny sedimentation of flours from the grinding of 120 varieties of bread wheat collected from different regions of Turkey. Therefore, spectra in the range of 1100 to 2500 nm of the flours were acquired by scanning with the NIRSystems 6500 monochromator. Multiple linear regression (MLR) and partial least squares (PLS) regression were applied to the spectral data in log 1/R, and first derivative and second derivative of log 1/R formats. Reasonable results were obtained for protein, wet and dry gluten contents, and Zeleny sedimentation with r = 0.985, 0.976, 0.953, and 0.924, respectively.
AtıfScopus41WoS38OpenAlex52İncele - MakaleAçık Erişim2010Scopus SJRQ4Social responsibility framework analysis of an event
Kaya, Nurullah; Yanik, Ramazan
One of the main objectives of the companies is to serve society. Companies, in fulfilling this objective, managers and employees, government, partners and customers are obliged to observe. Intense competition in the day, these elements do not sufficiently take into account firms, economic, environmental, cultural and social development can not be expected to lend support to continue their lives as well be considered. Study, in the last days of the giant car companies, vehicle recall in their understanding of social responsibility has been taken in.
- MakaleAçık Erişim2011Scopus SJRQ3The effects of silica fume and fly ash on the scaling resistance and flexural strength of pavement concretes
Yener, Engin; Hinislioğlu, Sinan
The purpose of this study is to investigate the effects of Silica Fume (SF) and Fly Ash (FA) additives on the frost salt scaling resistance and flexural strength properties of pavement concrete. An attempt is also made to attain a more durable and higher strength concrete by a suitable combination of Ordinary Portland Cement (OPC), SF and FA. SF and FA are used as cement replacement in proportions of 0, 5, 10% and 0, 5, 10, 15% by weight respectively. Flexural strength is tested after 7, 28 and 91 days of the lime saturated water curing period. The experimental results indicate that using FA only decreases while SF only slightly increases 28-days flexural strength. On the other hand, using SF and FA together shows relatively more strength gain. Among all those tested, maximum 28 days flexural strength of 4.53 MPa is obtained for the mix proportions of 85% OPC + 10% FA and 5% SF. SF significantly decreases the amount of liquid absorption by capillary suction and has a significant effect on the scaling resistance. In addition, all the ternary mixtures showes better scaling resistance than the control mixture with 100% OPC.
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