Sürdürülebilir Kalkınma Amaçları
Yazarlar
- 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 künye2018Scopus SJRQ2Determining the Patient-Specific Optimum Osteotomy Line for Severe Mandibular Retrognathia Patients
Şensoy, Abdullah Tahir; Kaymaz, Irfan; Ertaş, Ümit; Kiki, Ali
Purpose: The purpose of this study is to suggest a patient-specific osteotomy line to optimize the distractor position and thus to minimize the disadvantages of conventional mandibular distraction osteogenesis (MDO) protocols. In addition, this study also aims to compare the conventional MDO protocols with the new MDO protocol proposed in this study in terms of both orthodontic outcomes and mechanical effects of osteotomy level on callus stabilization by means of the finite element method. Methods: A preoperative patient-specific 3-dimensional bone model was created and segmented by using computed tomography images of an individual patient. Virtual orthodontic set-up was applied to the segmented model prior to the virtual surgery. In order to compare the proposed osteotomy line with the conventional lines used in clinical applications, virtual surgery simulations were performed and callus tissues were modelled for each scenario. The comparison of the success of each osteotomy line was carried out based on the occlusion of the teeth. Results: The osteotomy line determined using the method proposed in this study has resulted in far less malocclusion than the conventional method. Namely, any angular deviation from the optimum osteotomy line determined in this study might result in deep-bite or open-bite. On the other hand, the finite element analysis results have indicated that this deviation also negatively affects the callus stability. Conclusion: In order to achieve a better MDO treatment in terms of occlusion of the teeth and the callus stability, the location of the osteotomy line and the distractor position can be computationally determined. The results suggest that MDO protocol developed in this study might be used in clinic to achieve a better outcome from the MDO treatment.
AtıfScopus7WoS4OpenAlex8
İncele - MakaleYalnız künye2018Scopus SJRQ1Influence of high pressure torsion-induced grain refinement and subsequent aging on tribological properties of Cu-Cr-Zr alloy
Purcek, G.; Yanar, H.; Shangina, D.V.; Demirtas, M.; Bochvar, N.R.; Dobatkin, S.V.
Effects of ultrafine grain formation via high pressure torsion (HPT) and precipitation during aging on the microstructure, mechanical and tribological properties of a Cu-Cr-Zr alloy have been investigated systematically. HPT results in the formation of ultrafine-grained (UFG) structure in the alloy with an average grain/subgrain size of 155 nm which leads to remarkable improvement in its hardness and strength along with a reduction in elongation to failure. Aging of UFG alloy brings about further strengthening due to the precipitation. UFG formation by HPT increases substantially the wear resistance of Cu-Cr-Zr alloy and reduces the friction coefficient. The highest wear resistance and the lowest friction coefficient are obtained on the sample processed by HPT and subsequent aging. The dominant wear mechanism of the alloy varies depending on the applied processes. Adhesion with smearing is the predominant wear mechanism for the initial (warm extruded) samples having coarse-grained (CG) structure. UFG samples show less adhesional effect with less smearing, and a higher tendency to the formation of cracks, abrasion and delamination seem to be dominant in those samples. Oxidative wear mechanism is also operative in both CG and UFG alloy samples. It may be concluded from this study that a combined process including UFG formation by HPT and subsequent precipitation by artificial aging provides a simple and effective processing procedure for improving the strength, hardness and wear resistance of Cu–Cr–Zr alloys without modification of the chemical composition.
AtıfScopus96WoS91OpenAlex99İncele - MakaleAçık Erişim2018Scopus SJRQ2Synthesis and characterization of Zn-doped Mn3O4 thin films using successive ionic layer adsorption and reaction technique: Its structural, optical and wettability properties
Bayram, Ozkan; Ertargin, Mehmet Emrah; Igman, Erdal; Guney, Harun; Simsek, Onder
In this study, it is aimed to obtain Zn doped Mn3O4 (manganese oxide) nanostructured thin films on the soda lime glass substrates by successive ionic layer adsorption and reaction technique. The tetragonal crystal structure of the all thin films was detected using XRD spectroscopy. The average crystallite size of undoped Mn3O4 thin films was calculated to be 29 nm and for Zn-doped thin films, this value decreased to 23 nm with increasing Zn concentration. Characteristic peaks for thin films were also confirmed by RAMAN spectroscopy. The morphological structures of zinc-doped manganese oxide nano-sheets thin films were revealed by SEM. Using UV–Vis spectroscopy, it was found that the optical band gap of Mn3O4 thin films decreased from 2.05 to 1.73 eV with Zn doping. It has also been understood from the wettability analyzes of thin films that all thin films have a hydrophilic character. From all these analyzes, it is thought that the Zn doped Mn3O4 thin films have the potential to be used in supercapacitor applications.
AtıfScopus25WoS22OpenAlex25İncele - MakaleYalnız künye2018Scopus SJRQ3Energy and exergy analysis of a solid-oxide fuel cell power generation system for an aerial vehicle (ISSA- 2015–139)
Genç, Gamze; Sarikoç, Selçuk
This paper presents the performance of the solid-oxide fuel cell/gas turbine hybrid power generation system with heat recovery waste unit based on the energy and exergy analyses. The effect of air inlet temperature and air/fuel ratio on exergy destruction and network output is determined. For the numerical calculations, air inlet temperature and air fuel ratio are increased from 273 to 373 K and from 40 to 60, respectively. The results of the numerical calculations bring out that total exergy destruction quantity increases with the increase of air inlet temperature and air/fuel ratio. Furthermore, the maximum system overall first and second law efficiencies are obtained in the cases of air inlet temperature and air/fuel ratio equal to 273 K and 60, respectively, and these values are 62.09% and 54.91%.
AtıfScopus9WoS9OpenAlex12İncele - MakaleAçık Erişim2018Scopus SJRQ1Determination of effective constitutive parameters of inhomogeneous metamaterials with bianisotropy
Hasar, Ugur Cem; Buldu, Gul; Kaya, Yunus; Ozturk, Gokhan
A recursive algorithm is proposed to accurately extract the electromagnetic parameters of isotropic/bianisotropic metamaterial (MM) slabs of inhomogeneous structures. The algorithm is based on the recursive calculations of measured/ simulated forward and backward scattering (S-) parameters from previously extracted wave impedances and refractive indices of each homogeneous layer (except the analyzed intermediate layer) by a suitable retrieval method. There are two main advantages of our proposed method over existing extraction algorithms. First, it could retrieve the electromagnetic parameters of both isotropic and bianisotropic MM slabs. Second, it is applicable for electromagnetic parameter extraction of inhomogeneous structures. For validation of our method and assessing its accuracy over existing extraction methods, we used the simulation results of various inhomogeneous structures constructed by different isotropic/bianisotropic MM slabs (split-ring-resonator (SRR), SRR-wire, omega, and omega-wire). For completeness, the effects of noise present in S-parameters and iterative error (by increasing the value of iteration numbers) are examined to test the robustness of the proposed algorithm.
AtıfScopus43WoS42OpenAlex47İncele - Derleme MakaleYalnız künye2018Scopus SJRQ1Green roofs and facades: A comprehensive review
Besir, Ahmet B.; Cuce, Erdem
Based on United Nations Environment Program (UNEP), building sector accounts for 40% of total energy consumption. In European countries, 36% of total greenhouse gas emissions is attributed to buildings. In this respect, green roofs are considered to be one of the most appropriate sustainable solutions to resolve the urban heat island-related issues. Roofs account for nearly 20–25% of overall urban surface areas. Energy saving, thermal insulation, shading and evapotranspiration features highlight the key role of green roofs in overall thermal performance of buildings and microclimatic conditions of indoor environments. Within the scope of this research, the concept of green roofs and facades is comprehensively analysed in a holistic and thematic way. Following a historical overview of the technology, the research is split into various subfields such as energy saving in buildings through greenery systems, multifunctional thermal benefits including evapotranspiration, thermal insulation, shading and thermal comfort features, evaporative cooling for reducing cooling demand and minimising wind driven convection losses. The results achieved from the literature survey clearly indicate that green roofs and facades are key solutions to mitigate building-related energy consumptions and greenhouse gas emissions. According to the previous works, heat flow through the building roofs in summer can be reduced by approximately 80% via green roofs. The green roofs are reported to consume less energy in the range of 2.2–16.7% than traditional roofs during summer time. A similar tendency is observed for the winter season depending on regional and climatic conditions. The temperature difference between conventional and greens roofs in winter is found to be about 4 °C, which is remarkable. Energy demand of buildings in summer is highly dependent on the plant intensity as it is reported to be 23.6, 12.3 and 8.2 kWh/m2/year for extensive, semi-intensive and intensive greenery surface, respectively. Greenery systems are also capable of providing thermally comfortable indoor and outdoor conditions. It is underlined that the annual average accumulation of CO2 reaches the level of 13.41–97.03 kg carbon/m2 for 98 m2 of vertical greenery system. The results of this research can be useful for dwellers, builders, architects, engineers and policy makers to have a good understanding about the potential of green roofs and facades to mitigate building-related energy consumptions and carbon emissions in a renewable, sustainable, energy-efficient and cost effective way.
AtıfScopus547WoS435OpenAlex617İncele - Kitap BölümüYalnız künye2018Scopus SJRQ3Solar calculations of modified arch (Semi-spherical)-type greenhouse system for Bayburt City
Uğur, Çakir; Erol, Şahin; Kemal, Çomakli; Ayşegül, Çokgez Kuş; Aloui, F; Dincer, I
Solar energy is thought as the main source of all energy sources in the world, and it can be used in many applications like agricultural areas, heating-cooling or electricity production directly or indirectly. Greenhousing is the first one of the agricultural activities that solar energy can be used directly in. Greenhouses offer us suitable conditions which can be controlled easily for the growth of the plant, and they are made by using a covering material that allows the sunlight to enter into the system. Covering material can be glass, fibre glass, plastic or another transparent element. This study investigates the solar energy usability rates and solar energy benefitting rates of a semi-spherical (modified arch)-type greenhouse system according to different orientations and positions which exist under climatic conditions of Bayburt. In the concept of this study, it is tried to determine the best direction and best sizes of a semi-spherical greenhouse to get the best solar benefit from the sun. To achieve this aim, a modelling study is made by using MATLAB. However, this modelling study is run for some determined shapes and greenhouses, and it can be used for different shaped greenhouses or buildings. The basic parameters are determined as greenhouse azimuth angle, the rate of size of long edge to short and seasonal solar energy gaining of greenhouse.
AtıfScopus1OpenAlex2İncele - MakaleYalnız künye2018Scopus SJRQ1High temperature superplasticity and deformation behavior of naturally aged Zn-Al alloys with different phase compositions
Demirtas, M.; Kawasaki, M.; Yanar, H.; Purcek, G.
Two Zn-Al alloys, eutectoid Zn-22Al and dilute Zn-0.3Al, were processed through equal-channel angular pressing (ECAP). The ECAP-processed alloys were subjected to long-term natural aging at room temperature for 120 days in order to investigate the effect of long-term natural aging on high-temperature superplasticity and the deformation behavior of these alloys. The grain size of the Zn-22Al alloy increased from 200 nm after ECAP to 400 nm after the natural aging process. The Zn-0.3Al alloy with a grain size of 1.3 µm after ECAP demonstrated a reasonably stable microstructure with the grain size of ~ 1.7 µm after long-term natural aging. The naturally aged ultrafine-grained (UFG) Zn-22Al alloy showed an excellent superplastic elongation of about 1800% at 200 °C. Grain boundary sliding was determined as the dominant deformation mechanism in this alloy. On the contrary, a considerably low elongation to failure of 230% was recorded in the naturally aged fine-grained (FG) Zn-0.3Al alloy at 150 °C, and dislocation creep was evaluated as the main deformation mechanism for this alloy. Detailed microstructural analyses showed that the FG Zn-0.3Al alloy was exposed to grain boundary corrosion during the natural aging process due to the presence of Al precipitates at grain boundaries whereas such formation was not observed in the UFG Zn-22% Al alloy. Grain boundary sliding was hindered by grain boundary corrosion and the cavity nucleation at the corroded grain boundaries caused a premature failure leading to such a low elongation in the Zn-0.3Al alloy.
AtıfScopus30WoS30OpenAlex33İncele - MakaleYalnız künye2018Scopus SJRQ2Investigating 5-hydroxymethylfurfural formation kinetic and antioxidant activity in heat treated honey from different floral sources
Turkut, G. Merve; Degirmenci, Atiye; Yildiz, Oktay; Can, Zehra; Cavrar, Sevda; Yaylaci Karahalil, Fatma; Kolayli, Sevgi
The quality and biochemical properties of honey are affected by heating or during storage period. The most important biochemical reaction that occurs in this process is the Maillard reaction. HMF (5-hydroxymethylfurfural) is one of the major intermediate products in the Maillard reaction that can lead to quality reduction in heated honey. In this study, the effect of heating on the antioxidant activity, and colour values as Maillard reaction indicators of three different botanical honeys were investigated; the HMF formation was also determined. Temperatures of 50, 70 and 80 °C were applied on the honeys between 0 and 48 h. Total phenolic content, ferric reducing/antioxidant power and scavenging of 2,2-diphenyl-1-picrylhydrazyl free radical assays are used to determine the antioxidant capacity. Results showed that the formation of HMF and the antioxidant properties of honeys were significantly increased during the heating process. Pure HMF compound also showed lower antioxidant activity. The formation of HMF has higher degree of linearity in the fit of the zero order reaction and also it was the highest in the chestnut honey. Furthermore, it was found that as the biochemical value of the honeys increased, the HMF formation decelerated.
AtıfScopus45WoS35OpenAlex44İncele - MakaleYalnız künye2018Scopus SJRQ1Conjugated polythiophene/Ni doped ZnO hetero bilayer nanocomposite thin films: Its structural, optical and photoluminescence properties
Bayram, Ozkan
In this study, synthesis and characterization of plasma polymerized Thiophene/ Nickel doped Zinc Oxide (PTNZO) bilayer nanocomposite films were carried out. Nickel doped zinc oxide (NZO) thin films were obtained by magnetron sputtering technique on glass substrates at 40 W Radio Frequency (RF) power. Plasma polymerized Thiophene (PT) thin films were deposited on the NZO thin films obtained on the glass substrate by Radio Frequency (RF) plasma polymerisation technique. X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), FTIR and Photoluminescence (PL) analyzes were performed for the characterization of PTNZO hetero bilayer nanocomposite films. In the XRD spectra of PTNZO bilayer nanocomposite thin films, (002) planes were determined as the most basic peak, and it was determined that the intensity of this peak, changed depending on the RF power of polymer thin films. Optical properties of nanocomposite thin films such as transmittance, absorbance and optical band gap were determined by UV–Vis spectroscopy. Optical band gap for PTNZO nanocomposites were 2.72 eV, 2.34 eV, and 2.45 eV, respectively, with increasing RF power. For NZO thin films, this value is 3.12 eV. The optical band gaps calculated from the absorption and transmittance spectra obtained using UV–visible spectroscopy had a good compatibility with those of the optical band spectra calculated from the PL spectra. The tetragonal wurtzite structure of the NZO thin films was examined by SEM analysis. The grain size of NZO nanostructure was found to be approximately 59 nm.
AtıfScopus9WoS9OpenAlex9İncele - MakaleYalnız künye2018Scopus SJRQ3Melissopalynological analysis for geographical marking of Kars honey; [Kars balının coğrafi İşaretlemesi İçin melissopalinolojik analiz]
Çelemli, Ömür Gençay; Özenirler, Çiğdem; Bayram, Nesrin Ecem; Zare, Golshan; Sorkun, Kadriye
In this research, the melissopalynological analysis of honey samples collected from Kars city located in the East Anatolian Region of Turkey was conducted for geographical marking. Within this context, melissopalynological analyses of 100 honey samples determined by sampling method were collected from eight districts of Kars in Eastern Anatolia Region of Turkey were done, to determine the nectarous source plants of Kars honey. As a result of melisopalynological analyses carried out in 100 honey samples; pollens of the taxa belonging to Apiaceae, Asteraceae, Berberidaceae, Betulaceae, Brassicaceae, Boraginaceae, Campanulaceae, Caryophyllaceae, Chenopodiaceae, Cistaceae, Cyperaceae, Dipsacaceae, Ericaceae, Fabaceae, Iridaceae, Lamiaceae, Liliaceae, Malvaceae, Onagraceae, Papaveraceae, Plantaginaceae, Poaceae, Polygonaceae, Ranunculaceae, Rhamnaceae, Rosaceae, Rubiaceae, Rutaceae, Salicaceae and Scrophulariaceae families were detected at different rates. Almost in all of the honey samples, Lotus corniculatus (in 99 samples), Onobrychis radiata (in 99 samples), Trifolium nigrescens (in 88 samples) from Fabaceae family and pollens of Echium vulgaris (81 samples) and Myosotis lithoospermifolia (15 samples) taxa from the Boraginaceae family, were found in honey samples. Onobrychis radiata pollen was the most intensely observed one among these samples (in dominant, secondary, minor, trace amounts). The total number of pollens (TPN-10) in 10 grams of honey were also detected during the melissopalynological analyses. TPN-10 values minimum: 226, maximum: 481157 and mean: 31678 were detected and the pollen abundance of the honeys are classified as good category. Kars is an important province for beekeeping with floral variety. As a result of this study, the first step of the geographical marking studies of Kars’ honey was completed.
AtıfScopus17İncele - MakaleYalnız künye2018Scopus SJRQ1A new method for determination of dynamic stability of self-consolidating concrete: 3-Compartment sieve test
Gökçe, H. Süleyman; Andiç-Çakır, Özge
There are many standard test methods and applications to determine or estimate the workability of fresh concrete mixtures, most of them are focused on highly flowable concrete mixtures. Due to its high flowability, self-consolidating concrete (SCC) is much more vulnerable to segregation compared to conventional concrete mixtures. Thus, researchers have been working on adopting dynamic and static test methods for determination and improvement of segregation stability of those mixtures. In this study, the different segregation test methods presented in the literature were assessed and a novel method, i.e. 3-compartment sieve test, was introduced. The dynamic stability of fresh self-consolidating concrete mixtures was evaluated by the suggested test method after slump-flow and J-Ring tests. In conclusion, the developed new method is recommended for determination of segregation in SCC due to satisfactory concurrency of results with those of visual stability index test (0.67 ≤ R2 ≤ 0.90) and sieve segregation resistance test (0.83 ≤ R2 ≤ 0.90), respectively.
AtıfScopus23WoS19OpenAlex23İncele - BildiriYalnız künye2018Threshold effect on particle tracking algorithms
Yücel, Harun; Velu, Sabareesh K. P.; Oktem, Y.; Ozturk, F.C.; Dogan, G.S.; Guzelcimen, F.; Akkus, B.
Automated particle tracking algorithms are widely used by soft matter physicists as a research tool to detect and construct the trajectories of micron-sized particles in ffuids. Analyzing these trajectories will uncover the physics of the investigated particles mainly on the type of motion they undergo making them suitable for potential applications. A plethora of methods has been proposed and used for detection and tracking. In this work, we examine the performance of two commonly used tracking algorithms in terms of threshold dependencies in digital video images. One of them is the centroid method (CM), a well-known and used algorithm and the other is radial symmetry method (RSM) which is recently proposed. Here, we generate the synthetic digital video images consisting of randomly placed multiple particles and compare the absolute errors on the particle detection by varying threshold values. Our results suggest that both algorithms show dependence on the threshold value and on comparison RSM algorithm performs better than the CM algorithm when the noise level is zero. Moreover, the measured absolute errors show a strong dependence on threshold values when noise levels are increased (up to 20) especially for the RSM algorithm.
AtıfScopus1WoS1OpenAlex1İncele - MakaleYalnız künye2018Scopus SJRQ3Real-time implementation of self-tuning regulator control technique for coupled tank industrial process system
Ayten, Kagan Koray; Dumlu, Ahmet; Kaleli, Aliriza
This article presents the self-tuning regulator control technique for a coupled tank liquid level system that often used in industry. An autoregressive with exogenous model has been used as the liquid process model with the self-tuning control implementation in order to track the desired tank level trajectories with disturbances and uncertainties of the system dynamics. The designed self-tuning controller has been sensitive to parameter variations of the nonlinear coupled tank system. The parameters of the proposed controller are periodically updated themselves during the process by means of online recursive least square method with the forgetting factor algorithm. In this way, the parameter variations and unwanted disturbances of the system are eliminated in real-time application. In order to demonstrate the efficiency of the self-tuning regulator control technique, the real-time studies have been executed. The obtained experimental results demonstrated that the proposed controller gives the better trajectory tracking performance and smaller magnitude in overshot and undershot than the designed classical proportional–integral and sliding mode controllers.
AtıfScopus11WoS5OpenAlex10İncele - MakaleYalnız künye2018Scopus SJRQ3Drug likeness scoring and quantitative structure anaplastic lymphoma kinase (ALK) inhibitors activities relationships of pyrazolone derivatives
Ouadah, Karim; Tchouar, Noureddine; Belaidi, Salah; Oukil, Oualid; Cinar, Mehmet
Series of twenty-four compounds was the field for applying multi-parameter optimization (MPO) methods and qualitative approximations of structural activity relationships in order to determine the role of various physico-chemical and quantum descriptors used in QSAR modeling as independent variables. Anaplastic lymphoma kinase (ALK) inhibitory activity was considered as a component in this study. In order to illustrate the quantitative relationships between the molecular descriptors and the activity of pyrazolone derivatives, we have applied a multiple linear regression (MLR) procedure. By adopting cross-validation with the leave-one-out method, we could estimate the predictability of models. Our results suggest a QSAR model based on the following descriptors: S, V, LogP, POL, Ref, HOMO, LUMO, E, , HBA, PSA and NRB, for the inhibitory activities against ALK. Results show high correlation between experimental and predicted activity values, indicating the validation and the good quality of the QSAR model.
AtıfOpenAlex1İncele - MakaleYalnız künye2018Scopus SJRQ2Influence of coronene addition on some superconducting properties of bulk MgB2
Erdem, O.; Kirat, G.
This study reports the effect of coronene (C24H12) addition on some superconducting properties such as critical temperature (Tc), critical current density (Jc), flux pinning force density (Fp), irreversibility field (Hirr), upper critical magnetic field (Hc2), and activation energy (U0), of bulk MgB2 superconductor by means of magnetisation and magnetoresistivity measurements. Disk-shaped polycrystalline MgB2 samples with varying C24H12 contents of 0, 2, 4, 6, 8, 10 wt%, were produced at 850 °C in Ar atmosphere. The obtained results show an increase in field-Jc values at 10 and 20 K resulting from the strengthened flux pinning, and a decrease in critical temperature (Tc) because of C substitution into MgB2 lattice, with increasing amount of C24H12 powder. The Hc2(0) and Hirr(0) values are respectively found as 144, 181, 172 kOe, and 128, 161, 145 kOe for pure, 4 wt% and 10 wt% C24H12 added samples. The U0 depending on the magnetic field curves were plotted using thermally activated flux flow model. The maximum U0 values are respectively obtained as 0.20, 0.23 and 0.12 eV at 30 kOe for pure, 4 wt% and 10 wt% C24H12 added samples. As a result, the superconducting properties of bulk MgB2 at high fields was improved using C24H12, active carbon source addition, because of the presence of uniformly dispersed C particles with nanometer order of magnitude, and acting as effective pinning centres in MgB2 structure.
AtıfScopus12WoS12OpenAlex11İncele - MakaleAçık Erişim2018Scopus SJRQ2Active control of a small-scalewind turbine blade containing magnetorheological fluid
Bolat, Fevzi Cakmak; Sivrioglu, Selim
This research study proposes a new active control structure to suppress vibrations of a small-scale wind turbine blade filled with magnetorheological (MR) fluid and actuated by an electromagnet. The aluminum blade structure is manufactured using the SH3055 (BergeyWindpower Co. Inc., Norman, OK, USA) code numbered airfoil which is designed for use on small wind turbines. A dynamic interaction model between the MR fluid and the electromagnetic actuator is constructed to obtain a force relation. A detailed characterization study is presented for the proposed actuator to understand the nonlinear behavior of the electromagnetic force. A norm based multi-objective H2/H∞ controller is designed using the model of the elastic blade element. The H2/H∞ controller is experimentally implemented under the impact and steady state aerodynamic load conditions. The results of experiments show that the MR fluid- electromagnetic actuator is effective for suppressing vibrations of the blade structure.
AtıfScopus23WoS22OpenAlex22İncele - MakaleYalnız künye2018Scopus SJRQ4Examination of main trends in geographical education research in Turkey
Değirmenci, Yavuz
The main purpose of the present study is to examine the main tendencies of the articles published in the field of geography education between the years of 2008 and 2018 in Turkey. Within the scope of this purpose, this study examined the subject fields, research methods, data collection tools, data analysis techniques and sampling methods used in the geography education studies in the journals scanned by the SSCI, ESCI and ULAKBIM social sciences databases in Turkey. The study used the document analysis method, one of the qualitative research methods. The study evaluated 224 articles determined according to the purposeful sampling method from the related databases by using the Geography Education Article Classification Form (GEACF) and then analyzed the obtained pieces of data by using the content analysis method and finally made some interpretations. According to the findings of the study, in the last ten years in Turkey, the highest number of articles were published in 2010 (n=33) and the lowest number of articles were published in 2017 (n=13). It was also observed that, in the field of geography education, the highest number of articles were published in the Marmara Geography Journal; however, in the journals scanned in SSCI, a total of (n=17) articles were published in the last ten years. Moreover, the studies were also determined to show more interest in the subject areas of teacher training and learning/teaching; questionnaires and scales were generally used as a data collection tool; the frequency/percentage and content analysis methods were preferred in the analysis of data; quantitative and qualitative methods were generally used in studies on geography education; on the contrary, mixed methods were less frequently used.
- MakaleYalnız künye2018Scopus SJRQ2Optimum weight design of steel space frames with semi-rigid connections using harmony search and genetic algorithms
Artar, Musa; Daloğlu, Ayşe T.
In this paper, an optimization process using MATLAB-SAP2000 Open Application Programming Interface (OAPI) is presented for optimum design of space frames with semi-rigid connections. A specified list including W-profiles taken from American Institute of Steel Construction (AISC) is used in the selection of suitable sections. The stress constraints as indicated in load and resistance factor design of AISC, lateral displacement constraints being the top- and inter-storey drift and geometric constraints are considered in the optimization process. Genetic algorithm method based on biological principles and harmony search algorithm method based on the processes of musical harmony are used for optimum designs. Two different space frames are solved for the cases of rigid and semi-rigid connections, separately. A computer program is coded in MATLAB for the purpose interacting with SAP2000 OAPI. Results obtained from the analyses show that type of semi-rigid connections plays a crucial role in the optimization of steel space frames and increases the optimum weight.
AtıfScopus23WoS17OpenAlex30İncele - MakaleAçık Erişim2018Scopus SJRQ3Effects of choral, repeated and assisted reading strategies on reading and reading comprehension skills of poor readers
Kodan, Hülya; Akyol, Hayati
The main objective of this study was to explain the effects of choral, repeated and assisted reading strategies on fluent reading and reading comprehension skills of poor readers. The research was conducted with the single-subject research method and the multiple-subject model. The study group was consisted of six students who experience reading difficulties. The study was carried out in 90 hours. In the preliminary test, fluent reading and reading comprehension levels and reading mistakes of the students were determined. In this test, fluent reading level was lower than%89 and reading comprehension level was lower % 70, which showed that the students were at the Anxiety Level in both levels. During the study, choral, repeated and assisted reading strategies together had contributed to developments of the students’ fluent reading and reading comprehension skills both in the informative and the narrative texts. The data obtained during the research were analyzed by the Wilcoxon Signed-Rank Test. When examining the pre- and post assessment results, it was found that there was a significant difference between the word recognition percentages, number of incorrect words, number of words per minute, and the reading comprehension percentages in the informative text. In addition, it was articulated that there was a significant difference between the word recognition percentages, number of incorrect words, and the reading comprehension percentages in the narrative text. However, it was not found a significant difference between the numbers of words per minute in the narrative text. The data obtained at the end of the study shows that choral, repeated and assisted reading strategies have positive effects on the fluent reading and reading comprehension skills of the poor readers.
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