Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Kaygusuz, Abdullah(35)
- Sipahi, Ferkan(35)
- Karsli, Orhan(34)
- Dokuz, Abdurrahman(30)
- Duran, Celal(30)
- Kandemir, Raif(29)
- Ozdes, Duygu(28)
- Maden, Nafiz(27)
- Uzun, Sevda(27)
- Merdan, Mehmet(26)
- Vural, Alaaddin(26)
- Öztürk, Serkan(25)
- Araz, Onur(24)
- Kulakaç, Nurşen(24)
- Ashyralyyev, Charyyar(23)
- Yildiz, Salih(23)
- Yilmaz, Ozgur(23)
- Doğan, Kadir Caner(21)
- Arslan, Mehmet(20)
- Aydin, Faruk(20)
- Doğru, Bülent(20)
- Bayraktar, Alemdar(19)
- Kankal, Murat(19)
- Ayaydin, Hasan(18)
- Baltaci, Cemalettin(18)
- Yolcu, Halil(18)
- Cakir, Tufan(17)
- Cengiz, Ekrem(17)
- Demir, Selim(17)
- Gücer, Mehmet Ali(17)
- Akaryali, Enver(16)
- Artan, Seyfettin(16)
- Hayaloğlu, Pınar(16)
- Kaya, Afşin Ahmet(16)
- Tosunoğlu, Büşra(16)
- Uysal, Ibrahim(16)
- Kurt, Kemal(15)
- Ozturk, Samet(15)
- Reis, Hatice Catal(15)
- Aksakal, Vecihi(14)
Yayınlar
- MakaleYalnız künye2018Scopus SJRQ3Utilizing the sustainable livelihoods approach to evaluate tourism development from the rural host communities’ point of view: The case of Cappadocia (Turkey)
Çakir, Onur; Evren, Savaş; Tören, Emrullah; Kozak, Nazmi
The objective of this study was to contribute to and expand the limited knowledge base of the ways in which tourism development impacts rural livelihoods. It traced the process of tourism-based livelihood development in the Cappadocia region of Turkey by using The Sustainable Livelihoods Approach (SLA) framework to provide the perspectives of those who chose to incorporate tourism as a major part of their overall livelihood strategy. The results showed that tourism development had a great impact on the locals’ livelihoods. In order to enhance the locals’ livelihood and achieve an environmentally, socially, and economically sustainable outcome for tourism livelihood, the recommendation is to support and encourage small local establishments versus large scale foreign investments, increase the number of overnight stays by promoting Cappadocia as a main tourist destination, take precautions to prevent fraud and forgery in locale handicrafts and souvenir shops, and enact a protection law that prevents harm to the environment caused by traffic, shops, balloons, and hydroelectric power plants.
AtıfScopus12
İncele - MakaleYalnız künye2018Scopus SJRQ1Natural convection in a parallel-plate vertical channel with discrete heating by two flush-mounted heaters: effect of the clearance between the heaters
Sarper, Bugra; Saglam, Mehmet; Aydin, Orhan; Avci, Mete
In this study, natural convection in a vertical channel is studied experimentally and numerically. One of the channel walls is heated discretely by two flush-mounted heaters while the other is insulated. The effects of the clearance between the heaters on heat transfer and hot spot temperature while total length of the heaters keeps constant are investigated. Four different settlements of two discrete heaters are comparatively examined. Air is used as the working fluid. The range of the modified Grashof number covers the values between 9.6 × 105 and 1.53 × 10.7 Surface to surface radiation is taken into account. Flow visualizations and temperature measurements are performed in the experimental study. Numerical computations are performed using the commercial CFD code ANSYS FLUENT. The results are represented as the variations of surface temperature, hot spot temperature and Nusselt number with the modified Grashof number and the clearance between the heaters as well as velocity and temperature variations of the fluid.
AtıfScopus22WoS19OpenAlex22
İncele - MakaleYalnız künye2018Scopus SJRQ1Geometric optimization of an ejector for a 4 kW SOFC system with anode off-gas recycle
Genc, Omer; Toros, Serkan; Timurkutluk, Bora
One of the important energy saving tools used in solid oxide fuel cell (SOFC) system is the anode off-gas recycling (AGR) via an ejector which allows the recirculation of the unused fuels in the anode exhaust gas including hot steam which is essential for the elimination of the carbon deposition and the initiation of the reactions in the reformer. In an ejector system developed for the SOFCs, the steam to carbon ratio (STCR) and entrainment ratio are the crucial parameters for the determination of the ejector performance. These parameters can be engineered by modifying the geometric dimensions and operation conditions. This study focuses on the determination of the maximum STCR value and entrainment ratio via numerical geometric analyses for a micro combined heat and power (μ-CHP) system based on 4 kW SOFC, utilizing methane. A detailed numerical procedure for designing an ejector is provided and the ejector performance is investigated for different critical dimensions (throat diameter, nozzle exit angle and nozzle position etc.). The results show that the nozzle position and the nozzle exit angle significantly affect STCR and the entrainment ratio. When the nozzle position increases and nozzle exit angle decreases, the entrainment ratio and STCR is found to increase. The entrainment ratio and STCR are determined as around 7.3 and 2.7, respectively for a specific design created in the study.
AtıfScopus26WoS23OpenAlex24İncele - MakaleYalnız künye2018Scopus SJRQ4Volume calculation of brain structures in migraine disease by using mristudio
Palancı, Özgür; Kalaycıoğlu, Ahmet; Acer, Niyazi; Eyüpoğlu, İlker; Çakmak, Vildan A.
Migraine is a neurological disorder that is known as headache and accompanies attacks of neurological and gastrointestinal symptoms and prevents daily life activities of the person. In the literature, the volume changes of many structures in the brain have been investigated using brain magnetic resonance images (MRI) of migraine patients, but it has not yet been investigated whether there is a comprehensive and detailed volume change involving all the structures of the brain. The purpose of this study is to examine the brain structures in a wide range and to determine in which regions the volume changes. In this study, 25 healthy subjects and 25 migraine patients were included in the study. SPSS 15.0 program was used for statistical analysis. The Mristudio was used in our study when we examined the volumes of migraine patients and brain structures of healthy individuals. Statistically significant volume changes were found in the volumes of structures found in the brain frontal, parietal, occipital, temporal lobes. Volumetric changes were assessed in terms of duration of illness and frequency of attacks. In conclusion, our study is compatible with migraine pathophysiology. Structural changes in the brain are thought to be a risk factor for migraine. The evidence on the relationship of regional gray matter volumetric change detected in migraine is unclear. We believe that this ambiguity is caused by the method used.
AtıfScopus2OpenAlex2İncele - MakaleYalnız künye2018Scopus SJRQ3Automated Model Updating Effect on the Linear and Nonlinear Dynamic Responses of Historical Masonry Structures
Altunişik, A.C.; Okur, F.Y.; Genç, A.F.; Günaydin, M.; Karahasan, O.
Finite element models supply the simulation of the problems to obtain the structural behaviors under different loading conditions. The updating processes based on changing the uncertain parameters such as material properties, boundary conditions, meshing size etc. are made to create actual finite element models in order to represent the real conditions of the problems. This procedure can be made using two methods, namely manual model updating and global/local automatic model updating. The global/local automatic model updating procedures are very popular owing to the applicability to all kind of engineering structures, minimizing the differences nearly to zero, availability of damage localization and structural health monitoring. In this paper a historical masonry armory building selected as an application and its finite element analyses, experimental measurements and automated model updating processes are carried out. The finite element model of the structures was developed with ANSYS software and first three natural frequencies are attained. The experimental dynamic characteristics such as natural frequencies, damping ratios and mode shapes are obtained using ambient vibration method. The differences between experimental and numerical frequencies are minimized up to the range of 0–1%, by using local updating procedure. The linear and nonlinear seismic analyses of the building are conducted on initial and updated models. At the end of the analyses, maximum displacements, principal stresses and strains are given with detail. In addition, crack distributions diagrams are attained to validate the stresses accumulation points. It can be seen that there is an increasing trend in the displacement, stress and strain values after finite element model updating both linear and nonlinear analysis. In addition, linear and nonlinear analysis results are compared with each other to evaluate the nonlinear analysis effect. It is concluded that the displacement and strain values are increased after nonlinear analysis. But, there is not any agreement in stress values.
AtıfScopus17WoS15OpenAlex15İncele - MakaleYalnız künye2018Scopus SJRQ2An enhanced scanning-based MPPT approach for DMPPT systems
Başoğlu, Mustafa Engin
In this paper, an improved maximum power point tracking (MPPT) approach being low parameter dependency, simple structure and limited search interval has been presented for distributed MPPT photovoltaic (PV) systems. Basically, this approach is based on scanning of power–voltage (P-V) characteristic curve of PV modules in a limited duty ratio interval which makes tracking operation simple, fast and efficiently available in both uniform irradiance and partial shading conditions (PSCs). By limiting the scanning interval of maximum and minimum values of duty ratio via some analyses related to P-V characteristic for PSCs, global MPPT (GMPPT) is achieved in an efficient way. So as to validate performance of the proposed approach, a single-ended primary inductance converter has been used in both simulation and experimental studies. PV simulator has been used as a PV source to obtain different module characteristics with different number of bypass diodes and PV power levels. Both simulation and experimental results clarify that improved MPPT approach realises GMPPT effectively. Due to the high performance results, this approach can be an alternative technique in module-integrated converters, smart modules and PV power optimisers in which single module is used.
AtıfScopus27WoS23İncele - MakaleYalnız künye2018Scopus SJRQ3Solving power transmission line routing problem using improved genetic and artificial bee colony algorithms
Eroğlu, Hasan; Aydin, Musa
In engineering studies, finding the best route from a start point to an end point on pixel-based weighted maps is a big problem for researchers. For this problem many methods and algorithms have been developed until now. The “cost distance” (CD) and “cost path” (CP) tools that are used by a modified Dijkstra’s algorithm and used by Environmental Systems Research Institute’s (ESRI) ArcGIS Desktop 10 software are very fast and most preferred solutions for route optimization problems. Despite the advantages of these tools, they have the disadvantage of making a lot of curves with big angles. Especially in some engineering studies like power transmission lines’ routing, the angle of the curves of the lines should not have big values. For overcoming this problem both genetic algorithm (GA) and artificial bee colony (ABC) algorithm that have been improved and adapted for the problem were used as powerful optimizers to find the best routes with fewer curves in those kinds of optimum route problems. New functions like smart direction sensing and improved random functions were developed for application of GA and ABC algorithms in power transmission lines routing studies. This study showed that the ABC algorithm’s performance is better than GA. The accuracy of the algorithms was proven by comparing the results with the CD–CP tools’ results. The experimental results showed that the improved algorithms gave better performance than Dijkstra’s algorithm.
AtıfScopus15WoS12OpenAlex17İncele - MakaleYalnız künye2018Scopus SJRQ4Optimization of drying parameters for chestnut fruits using central composite design
Koca, I.; Yilmaz, V.A.; Odabas, I.H.; Tekguler, B.
The chestnut drying process was optimized by Response Surface Methodology (RSM). A central composite design with two numerical factors was selected for modelling the drying process. The numerical factors were air temperature from 40 to 60°C and air velocity from 0.75 to 1.75 m s-1. The investigated responses were color values, including lightness (L*), redness (a*), yellowness (b*), total color changes (ΔE) and browning index (BI). The study revealed that the drying temperature was significantly effective on lightness, redness, total color changes and browning index. However, none of the independent variables were significant on yellowness. The L*, a*, ΔE and BI of chestnuts during drying process were adequately described by RSM models. According to desirability function, the optimum drying conditions of chestnuts were 40°C and 0.75 m s-1 air. At optimum conditions, predicted L*, a*, ΔE and BI values were 76.34, -0.20, 7.45 and 17.00, respectively. Under optimized conditions the experimental values of L* (77.46), a* (-0.36), ΔE (6.31) and BI (16.88) agreed with the predicted values. RSM was not successful to develop a satisfactory model for b* values of chestnuts during drying process.
AtıfScopus2OpenAlex1İncele - MakaleYalnız künye2018Scopus SJRQ4Open source library-based 3D face point cloud generation
Bayram, Bulent; Ozkan, Taskin; Reis, Hatice Catal; Bakirman, Tolga; Cetin, Ibrahim; Seker, Dursun Zafer
Three dimensional (3D) face and body modeling is widely used in various fields such as plastic surgery, diagnosis of facial or body anomalies, 3D computer games and 3D simulation software. Since, commercial 3D face and body scanners are usually expensive, an alternative solution with lower cost is highly desirable. The objective of this study is to create 3D facial point cloud using Semi Global Image Matching method with minimum number of images utilizing a cost effective method. A non-metric Canon 600D camera with 18 megapixels resolution (3456 × 5184) and 60 mm macro lens have been used for face imaging that have been taken from a distance of 120 cm. Five faces have been modeled by the developed algorithm and scanned by David SLS-2 structured light system for accuracy assessment. Open source Cloud Compare software has been used for comparing the results of proposed method with the structured light system. The mean accuracy of five faces obtained as 90.5%. It has been observed that illumination conditions, uncontrolled movements of face or body, hair and eyebrow have negative impacts on the obtained results. The sufficiency of Semi global image matching method has been tested to create dense point cloud data from three stereo pairs for 3D facial modelling.
AtıfScopus3WoS2İncele - MakaleYalnız künye2018Scopus SJRQ3Geochemistry of Çoruh River Bed Sediments in NE Turkey: Implications in Weathering-Sedimentary Cycle, Provenance, and Metal Pollution
Eker, Ç.Saydam.; Kiliç, E. Demirkol
This study defines the source area, sub-aerial weathering, and sedimentary cycle level, as well as heavy metal content and origin, of the Çoruh River bed sediments. The studied sediments are geochemically classified as litharenite based on the ratio of the major element contents. Relative to the Upper Continental Crust (UCC), trace elements Rb, Sr, Ba, Th, U, Zr, Hf, Y, Nb, and Pb are generally depleted; Co, Ni, Cu, Sc, and V are generally enriched; and Au is depleted in some places and enriched in other places. The rare earth element (REE) distributions of the samples exhibit a trend similar to that of the upper continental crust (UCC); however, low to moderate depletion occurs in the bed sediments in UCC. The analyzed samples exhibit low Chemical Index of Alteration (CIA) values, Plagioclase Index of Alteration (PIA) values (<50), CIA/WIP (Weathering Index ratios <1), and substantially high Index of Compositional Variability values (ICV) (>1). Thus, the samples are not chemically mature and are mainly derived from non-altered sources and were exposed the simple cycling history. REEs are depleted in the river bed sediments, unlike the world river average silt, world river average clay, and suspended sediment in world rivers. Minor enrichment of Zn, Sn, and Sc contents, low-to-moderate enrichment of Cu content, very severe enrichment of as content, and extremely severe enrichment of Ni content of the analyzed samples are observed. Consequently, stream bed sediments are derived from intermediate sources close to mid-continental crust rather than felsic sources Low-to-moderate degrees of chemical weathering of these sediments indicate increased tectonic activity, increased erosion, and rapid sedimentation in semiarid to arid conditions in the source regions over time. Thus, the sediments are chemically immature. These sediments are exposed to lithogenic and anthropogenic contamination.
AtıfScopus19WoS17OpenAlex21İncele - MakaleYalnız künye2018Scopus SJRQ2Differential scanning calorimetry (DSC) and Ni+2 release analysis of NiTi-shape-memory dental alloys coated by micro-arc oxidation (MAO) method
Yeşildal, Ruhi; Karabudak, Filiz; Şüküroğlu, Ebru Emine; Şüküroğlu, Süleyman; Zamanlou, Hamid; Bayındır, Funda; Şen, Sadri; Totik, Yaşar
This study aims to prevent the release of Ni+2 and increase the biocompatibility of NiTi-shape-memory dental alloys with the micro-arc oxidation (MAO) coating by preserving the shape-memory feature in the oral environment. The TiO2-ceramic coating and Ag-doped TiO2 coating have been grown on shape-memory, co-atoms’ dental NiTi alloys with the MAO method. Biocompatibility properties of the coating were determined by in-vitro tests. In-vitro tests have been made as retention tests in a simulated body fluid (SBF). Whether the grown surface coating impacts the shape-memory properties of the base material or not has been determined by differential scanning calorimetry (DSC) analysis. It was observed as a result of retention tests that bone-like apatite form occurred on the surface of TiO2-coated NiTi and Ag-doped TiO2-coated NiTi coating. It was determined as a result of retention tests in SBF that the Ni+2 release rate from the base material was below the limit of detection in coated samples. As a result of DSC analysis, it was not observed any significant changes in transformation temperature with the MAO coating. It was concluded that the thin-film coatings formed by MAO technique prevent the release of Ni in the oral environment and increase the biocompatibility by preserving shape memory properties of NiTi dental alloys.
AtıfScopus10WoS9OpenAlex10İncele - MakaleYalnız künye2018Scopus SJRQ1Carrier transport mechanism and bipolar resistive switching behavior of a nano-scale thin film TiO2 memristor
Gul, Fatih
A titanium dioxide (TiO2) based memristor device having an active layer thickness of 10 nm was fabricated using radio frequency (RF) reactive sputtering and its resistive switching characteristics and carrier transport mechanisms were investigated. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used to confirm the structural properties of the device. Measurement of the time-dependent current-voltage (I-V-t) was used to characterize resistive switching and memristive behavior. The characteristic pinched hysteresis I-V loops of the memristor were apparent. Bipolar and homogeneous resistive switching characteristics and a forming voltage of 2 V were detected in the device. The retention time exceeded 103 s and the endurance test was reasonably acceptable. In addition, the carrier transport mechanism of the device was revealed. The linear region of the low electric field demonstrated ohmic behavior, whereas the non-linear high electric field region was dominated by a Schottky emission carrier transport mechanism. A Poole-Frenkel emission mechanism acted as a secondary conduction mechanism. It was proposed that the Poole-Frenkel and Schottky emission mechanisms were associated with oxygen vacancies in the TiO2.
AtıfScopus69WoS69OpenAlex77İncele - BildiriYalnız künye2018Seasonal Variation of the Monthly Efficiencies of Thin Film PV Modules
Özden, Talat; Turan, Raşit; Akmoǧlu, Bülent Gültekin; Zaz, Y.; Essaaidi, M.
Outdoor testing of solar photovoltaic (PV) modules must be carried out at different climates as PV power plants nowadays are installed and continues to be installed in many countries. Present study is outdoor testing results and analyses of 5 thin film modules in Ankara, Turkey. The analyses are carried out using monthly efficiencies of the modules that are derived using the energy yield and input. The average efficiencies of the CIS, CIGS and μc-Si/a-Si thin film modules are. We present the monthly and average efficiencies and discuss their variations with the parameter: input, ambient temperature and relative humidity. We also carried out seasonal analyses using Pearson's correlation coefficient and find out that the efficiencies are differently dependent on the above mentioned parameters. This arose a new open question on differentiation of the strength of the effect of each parameter on the monthly efficiencies.
AtıfScopus1WoS1OpenAlex1İncele - MakaleYalnız künye2018Scopus SJRQ2Earthquake hazard potential in the Eastern Anatolian Region of Turkey: seismotectonic b and Dc-values and precursory quiescence Z-value
Öztürk, S.
The Eastern Anatolian Region of Turkey is one of the most seismically and tectonically active regions due to the frequent occurrence of earthquakes. Thus, the main goal of this study is to analyze the regional and temporal characteristics of seismicity in the Eastern Anatolia in terms of the seismotectonic b-value, fractal dimension Dc-value, precursory seismic quiescence Z-value, and their interrelationships. This study also seeks to obtain a reliable empirical relation between b and Dc-values and to evaluate the temporal changes of these parameters as they relate to the earthquake potential of the region. A more up-to-date relation of Dc = 2:55–0:39*b is found with a very strong negative correlation coefficient (r =–0.95) by using the orthogonal regression method. The b-values less than 1.0 and the Dc-values greater than 2.2 are observed in the Northeast Anatolian Fault Zone, Aşkale, Erzurum, Iğdır and Çaldıran Faults, Doğubeyazıt Fault Zone, around the Genç Fault, the western part of the Bitlis-Zagros Thrust Zone, Pülümür and Karakoçan Faults, and the Sancak- Uzunpınar Fault Zone. In addition, the regions having small b-values and large Z-values are calculated around the Genç, Pülümür and Karakoçan Faults as well as the Sancak-Uzunpınar Fault Zone. Remarkably, the combinations of these seismotectonic parameters could reveal the earthquake hazard potential in the Eastern Anatolian Region of Turkey, thus creating an increased interest in these anomaly regions.
AtıfScopus51WoS36OpenAlex53İncele - MakaleYalnız künye2018Scopus SJRQ2Tracing provenance and chemical weathering changes in Ankara Stream sediments, central Turkey: Geochemical and Sr–Nd–Pb–O isotopic evidence
Saydam Eker, Çiğdem; Sipahi, Ferkan; Gümüş, Mustafa Kemal; Özkan, Özay
This study aims to analyze the changes in sediment provenance through the geochemical and Sr–Nd–Pb–O isotopic composition of the Ankara Stream bed and overbank sediments (ASBS and ASOS) and to examine the weathering and sediment transport processes in response to step climate variability. Major, trace, and rare earth elements, as well as Sr–Nd–Pb–O isotopic composition, exhibit generally similar variations for the investigated samples. These sediments have relatively high εNd(0) values and low 87Sr/86Sr ratios. Similar Pb isotopic ratios also characterize these sediments but have slightly different δ18O isotope values with relatively higher δ18O isotope values in the ASBS and lower δ18O isotope values in the ASOS samples. Chemical indices indicate low–moderate chemical weathering in the step-dominated climate. The low average Zr/Sc and Zr/Nb ratios indicate that such geochemical change was dominated by the composition of the source rocks but not sedimentary recycling with zircon enrichment, reflecting first-cycle deposit. Low radiogenic 87Sr/86Sr ratios and negative εNd(0) values indicate that the investigated sediments are relatively derived from young magmatic provinces, which are intermediate sources. Finally, the findings show that the geochemical compositions of the ASBS and ASOS were dominated by the composition of the source materials that originate from Galatia province and Late Cretaceous- Early Tertiary volcanic rocks in central Anatolia. Reasonable semiarid to arid climatic conditions are observed in the region. Active tectonism, increased erosion, and the investigated sediments are also transported rapidly to the stream channel without chemical alteration, and the sediments are the first-cycle products.
AtıfScopus9WoS7OpenAlex10İncele - MakaleYalnız künye2018Scopus SJRQ2Lipophilization of chitin as novel polymeric stabilizer for improved oil-in-water emulsions
İlyasoğlu, Huri; Anankanbil, Sampson; Nadzieja, Marcin; Guo, Zheng
To develop novel polymeric emulsifiers/stabilizers for improved functionalities, an array of chitin fatty acid esters (chitin octanoate, laurate, palmitate, and stearate) were synthesized using a trifluoroacetic anhydride (TFAA)/methanesulfonic acid (MSA) catalytic system. The synthesized products were characterized by Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), and differential scanning calorimetry (DSC); successful lipophilization of chitin was confirmed by analysis results of FTIR, NMR, and DSC, with the degree of substitution (DS) of the products that ranged from 0.89 to 1.05. Ten percent fish oil-in-water emulsions were prepared using the synthesized chitin fatty acid esters, and characteristic properties (droplet size, zeta potential, and creaming stability) were determined. It turned out that chitin octanoate and chitin laurate were capable to solely enable homogeneous nanoemulsion (200–240 nm, polydispersity index 0.22–0.26), with excellent stability (no creaming after 14-day storage), which may find great potential applications in food, biomedical, and cosmetics sectors.
AtıfScopus4WoS4OpenAlex6İncele - MakaleYalnız künye2018Scopus SJRQ2Constructal Placement of Discrete Heat Sources with Different Lengths in Vertical Ducts under Natural and Mixed Convection
Sarper, Bugra; Saglam, Mehmet; Aydin, Orhan
In this study, convective heat transfer in a discretely heated parallel-plate vertical channel which simulates an IC package is investigated experimentally and numerically. Both natural and mixed convection cases are considered. The primary focus of the study is on determining optimum relative lengths of the heat sources in order to reduce the hot spot temperature and to maximize heat transfer from the sources to air. Various values of the length ratio and the modified Grashof number (for the natural convection case)/the Richardson number (for the mixed convection case) are examined. Conductive and radiative heat transfer is included in the analysis while air is used as the working fluid. Surface temperatures of the heat sources and the channel walls are measured in the experimental study. The numerical studies are performed using a commercial CFD code, ANSYS FLUENT. The variations of surface temperature, hot spot temperature, Nusselt number, and global conductance of the system are obtained for varying values of the working parameters. From the experimental studies, it is showed that the use of identical heat sources reduces the overall cooling performance both in natural and mixed convection. However, relatively decreasing heat sources lengths provides better cooling performance.
AtıfScopus11WoS11OpenAlex12İncele - MakaleYalnız künye2018Scopus SJRQ1Analytical solution to continuous contact problem for a functionally graded layer loaded through two dissimilar rigid punches
Polat, Alper; Kaya, Yusuf; Özşahin, Talat Şükrü
A continuous contact problem of functionally graded layer resting on an elastic semi-infinite plane, which is loaded with through two different blocks is addressed in this study. The elasticity theory and integral transformation techniques are used in solution of the problem. The problem is reduced to a system of singular integral equations, and solved numerically by the aid of appropriate Gauss–Chebyshev integration formula. It is assumed that the elastic semi-infinite homogeneous plane is isotropic and all surfaces are frictionless and continuous. The shear modulus and the mass density of the FG layer vary exponentially along the thickness direction.
AtıfScopus19WoS18OpenAlex15İncele - Derleme MakaleYalnız künye2018Scopus SJRQ1A Review Study on the Using of Diethyl Ether in Diesel Engines: Effects on Fuel Properties and Engine Performance
Sezer, İsmet
This study was compiled from the results of various researches performed on using diethyl ether as a fuel or fuel additive in diesel engines. Three different techniques are used the reduction of the harmful exhaust emissions of diesel engines. The first technique for the reduction of harmful emissions is improved the combustion by modification of engine design and fuel injection system, but this process is expensive and time consuming. The second technique is the using various exhaust gas devices like catalytic converter and diesel particulate filter. However, the use of these devices affects negatively diesel engine performance. The final technique to reduce emissions and also improve diesel engine performance is the use of various alternative fuels or fuel additives. The major pollutants of diesel engines are oxides of nitrogen (NOx) and particulate matter (PM). It is very difficult to reduce NOx and PM simultaneously in practice. The most researches declare that the best way to reduce is the use of various alternative fuels i. e. natural gas, biogas, biodiesel or using the additives with alternative fuels or conventional diesel fuel. Therefore, it is very important that the results of various studies on alternative fuels or fuel additives are evaluated together to practice applications. Especially, this study focus on the use diethyl ether in diesel engines as fuel or fuel additive in various diesel engine fuels. This review study investigates the effects of diethyl ether addition on the fuel properties and performance characteristics.
AtıfScopus17WoS15OpenAlex19İncele - MakaleYalnız künye2018Scopus SJRQ3In vitro antioxidant and antimicrobial activities of the five different solvent extracts of Centaurea pulcherrima var. Freynii from Turkey
Ozcan, Kadriye; Acet, Tuba
Various extracts of Centaurea pulcherrima var. freynii were investigated for total phenolic, flavonoid, antioxidant and antimicrobial activities. The antioxidant properties of plant extracts were evaluated by free radical scavenging assays (DPPH and ABTS). Antimicrobial activities were examined using disc diffusion methods. According to the results of antioxidant capacity assays, the plant showed moderately antioxidant activity in test methods. It was found that ethyl acetate extract showed the most effective activity including total phenolic, flavonoid, antioxidant and antimicrobial activities.
AtıfScopus11WoS10İncele