Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Uzun, Sevda(77)
- Merdan, Mehmet(73)
- Duran, Celal(54)
- Ozdes, Duygu(50)
- Baltaci, Cemalettin(45)
- Kaygusuz, Abdullah(45)
- Kulakaç, Nurşen(39)
- Ashyralyyev, Charyyar(38)
- Karsli, Orhan(37)
- Demir, Selim(36)
- Öztürk, Serkan(36)
- Dokuz, Abdurrahman(35)
- Turan, Ibrahim(35)
- Araz, Onur(33)
- Kandemir, Raif(31)
- Sipahi, Ferkan(30)
- Topal, Fevzi(30)
- Kurt, Kemal(28)
- Peker, Iskender(28)
- Arslan, Mehmet(27)
- Baltacı, Cemalettin(27)
- Maden, Nafiz(27)
- Ozturk, Samet(27)
- Aydin, Aydanur(26)
- Vural, Alaaddin(26)
- Bayrakdaroglu, Serdar(25)
- Kurnaz, Muammer(25)
- Reis, Hatice Catal(25)
- Akar, Zeynep(24)
- Aydin, Faruk(24)
- Gücer, Mehmet Ali(24)
- Topal, Meryem(24)
- Yolcu, Halil(24)
- Yücel, Cem(24)
- Anaç, Halil(23)
- Kankal, Murat(23)
- Ürkek, Bayram(23)
- Aliyazicioglu, Yuksel(22)
- Günen, Mehmet Akif(22)
- Tuncer, Metin(22)
Yayınlar
- BildiriYalnız künye2018The Relationship between Corruption and Tax Burden: The Moderator Effect of Strength of Auditing and Reporting Standards
Yesilcelebi, Gul; Keyifli, Nazli; Procházka, D.
The aim of this study is to examine the moderator effect of strength of auditing and reporting standards on the relationship between corruption and tax burden in the Organisation for Economic Co-operation and Development (OECD) countries. The study was conducted on annual data during the period 2011–2015 about the corruption, tax burden and strength of auditing and reporting standards of OECD member countries. In this context, data of corruption (Corruption Perceptions Index – CPI) were collected from Transparency International – the Global Coalition against Corruption; data of tax burden were collected from International Monetary Fund (IMF) database, and data of strength of auditing and reporting standards were collected from The Global Competitiveness Reports. The study analysed the relationship between corruption and tax burden and the moderator effect of strength of auditing and reporting standards on the relationship between two variables by the panel data analysis. The results of this analysis showed that have significantly and a negative relationship between corruption and tax burden; strength of auditing and reporting standards have significantly and a positive strengthen relationship between corruption and tax burden.
AtıfScopus1WoS1OpenAlex2
İncele - MakaleYalnız künye2018Scopus SJRQ1New xylanolytic enzyme from Geobacillus galactosidasius BS61 from a geothermal resource in Turkey
Sari, Bilge; Faiz, Ozlem; Genc, Berna; Sisecioglu, Melda; Adiguzel, Ahmet; Adiguzel, Gulsah
In this study, isolation, conventional and molecular characterizations of ten thermophilic bacteria from Rize/Ayder were carried out. Xylanase from Geobacillus galactosidasius BS61 (GenBank number: KX447660) was purified by acetone precipitation, Diethylaminoethyl-cellulose and Sephadex G-100 chromatographies. The xylanase of G. galactosidasius BS61 in clarifying fruit juice was also investigated. Enzyme was purified 29.80-fold with 75.18% yield; and molecular weight was determined as 78.15 kDa. The optimum temperature of xylanase was 60 °C. The enzyme activity was maintained fully after 24 h and over 50% after 168 h at pH 4.0–10.0, while optimum pH was 7.0. Km and Vmax for beech wood xylan were measured as 3.18 mg mL−1, 123 U mg protein−1. In addition, Ca2+, Na+, Al3+, Zn2+, Cd2+, Mg2+, Ni2+, Cu2+ had decreasing effect on enzyme activity, while enzyme activity had been protected against anions, especially HSO3− and HPO4 2− stimulated enzyme activity. Xylanase applications (with 15 U/mL enzyme activity) in orange and pomegranate juices were increased; and the sugar and turbidity amounts were reduced 17.36% ± 1.18 and 30.52 ± 1.23, respectively. These results indicated that the xylanase of G. galactosidasius BS61 has biotechnological potential in juice clarification due to its stability against metal ions, chemicals and high pH-values.
AtıfScopus21WoS18OpenAlex22
İncele - MakaleAçık Erişim2018Scopus SJRQ3Antioxidant activity, sugar content and phenolic profiling of blueberries cultivars: A comprehensive comparison
Okan, Onur Tolga; Deniz, Ilhan; Yayli, Nurettin; Şat, Ihsan Güngör; öz, Mehmet; Serdar, Gönül Hatipoğlu
Commercial blueberry production has been a viable industry throughout the world for 95 years; because of blueberry is a good source of antioxidant. Blueberries are especially rich in anthocyanin, a flavonoid with potent antioxidant capacity. The aim of this study was to compare the phenolic quantities, antioxidant activities, anthocyanin, sugar and phenolic compounds of blueberries produced in Turkey with those of similar blueberry varieties produced around the world. As a result of the conducted analysis, the total phenolic content (TPC) amount found in the berries was 77.26-215.12 mg GAE/100 g, the total flavonoid content (TFC) was 30.44-91.69 mg QE/100 g and the total anthocyanin content (TAC) was 43.03-295.06 mg c3- GE/100 g. Examining the antioxidant activities of the berries, DPPH between 1.10-5.65 mg/ml, FRAP between 454.93- 36832.96 μmol troloks/100 g, β-Carotene between 40.66-86.48%. It was determined that the natural berries contained much more phenolic compounds and higher antioxidant activity than that of the cultivars The result of HPLC analysis, chlorogenic acid is determined to be the dominant compound in all berries. Furthermore, fructose and glucose are found in all fruits in different quantities while sucrose is found in certain varieties of berries as well. At the end of the performed study the data indicate that wild and cultivars of blueberries are rich sources of antioxidants for local as well international industries importing this fruit for food processing and enormous products.
AtıfScopus70WoS69OpenAlex76İncele - BildiriAçık Erişim2018Tribological Behaviour of Ti:Ta-DLC Films under Different Tribo-Test Conditions
Efeoglu, İhsan; Keleş, Ayşenur; Totik, Yaşar; Cicek, Hikmet; Süküroglu, Ebru Emine; Hamamci, M.; Gocer, A.; Karamis, M.B.; Nair, F.; Savas, S.
Diamond-like carbon (DLC) films are suitable applicants for cutting tools due to their high hardness, low friction coefficient and wear rate. Doping metals in DLC films have been improved its tribological properties. In this study, titanium and tantalum doped hydrogenated DLC films were deposited by closed-field unbalanced magnetron sputtering system onto M2 high speed steels in Ar/N2/C2H2 atmosphere. The friction and wear properties of Ti:Ta-DLC film were investigated under different tribo-test conditions including in atmospheric pressure, distilled water, commercial oil and Ar atmosphere. The coated specimens were characterized by SEM and X-ray diffraction techniques. The bonding state of C-C (sp3) and C=C (sp2) were obtained with XPS. The tribological properties of Ti:Ta-DLC were investigated with pin-on-disc wear test. Hardness measurements performed by micro-indentation. Our results suggest that Ti:Ta-doped DLC film shows very dense columnar microstructure, high hardness (38.2 GPa) with low CoF (μ ≈0.02) and high wear resistance (0.5E-6 mm3/Nm).
AtıfScopus7WoS5OpenAlex8İncele - MakaleAçık Erişim2018Scopus SJRQ1A study of Bos taurus muscle specific enolase; biochemical characterization, homology modelling and investigation of molecular interaction using molecular docking and dynamics simulations
Sariyer, Emrah; Yakarsonmez, Sinem; Danis, Ozkan; Turgut-Balik, Dilek
Tropical theileriosis caused by Theileria annulata obligate parasite that infect ruminant animals, including Bos taurus. The disease results massive economic losses in livestock production worldwide. Here we describe cloning, expression and both biochemical and structural characterization of beta enolase from Bos taurus in vitro and in silico. The interconversion of 2‑phosphoglycerate to phosphoenolpyruvate was catalyzed by enolase is a metalloenzyme in glycolytic pathway and gluconeogenesis. Enolase from Bos taurus was cloned, expressed and the protein was purified at 95% purity using cobalt column by affinity chromatography. The optimum enzymatic activity was calculated at pH 6.5. For the first time in the literature, the kinetic parameters of the enzyme, Vmax and Km, were measured as 0.1141 mM/min and 0.514 mM, respectively. Besides, Bos taurus enolase 3-dimensional structure was built by homology modelling to be used in silico analyses. The interactions of the enzyme-substrate complex were elucidated by molecular dynamics simulations for 100 ns. These interactions were found to be the same as experimentally determined interactions in yeast. These results would enable further structure based drug design studies with the biochemical characterization of the host organism Bos taurus enolase enzyme in vitro and the elucidation of behavior of enzyme-substrate complex in silico.
AtıfScopus7WoS7OpenAlex7İncele - MakaleAçık Erişim2018Scopus SJRQ2Comparison of landscape metrics for three different level land cover/land use maps
Sertel, Elif; Topaloğlu, Raziye Hale; Şallı, Betül; Algan, Irmak Yay; Aksu, Gül Aslı
This research aims to investigate how different landscape metrics are affected by the enhancement of the thematic classes in land cover/land use (LC/LU) maps. For this aim, three different LC/LU maps based on three different levels of CORINE (Coordination of Information on The Environment) nomenclature were created for the selected study area using GEOBIA (Geographic Object Based Image Analysis) techniques. First, second and third level LC/LU maps of the study area have five, thirteen and twenty-seven hierarchical thematic classes, respectively. High-resolution Spot 7 images with 1.5 m spatial resolution were used as the main Earth Observation data to create LC/LU maps. Additional geospatial data from open sources (OpenStreetMap and Wikimapia) were also integrated to the classification in order to identify some of the 2nd and 3rd level LC/LU classes. Classification procedure was initially conducted for Level 3 classes in which we developed decision trees to be used in object-based classification. Afterwards, Level 3 classes were merged to create Level 2 LC/LU map and then Level 2 classes were merged to create the Level 1 LC/LU map according to CORINE nomenclature. The accuracy of Level 1, Level 2, Level 3 maps are calculated as; 93.50%, 89.00%, 85.50% respectively. At the last stage, several landscape metrics such as Number of Patch (NP), Edge Density (ED), Largest Patch Index (LPI), Euclidean Nearest Neighbor Distance (ENN), Splitting Index (SPLIT) and Aggregation Index (AI) metrics and others were calculated for different level LC/LU maps and landscape metrics values were compared to analyze the impact of changing thematic details on landscape metrics. Our results show that, increasing the thematic detail allows landscape characteristics to be defined more precisely and ensure comprehensive assessment of cause and effect relationships between classes.
AtıfScopus84WoS73OpenAlex88İncele - MakaleYalnız künye2018Scopus SJRQ2Bearing capacity and slope stability assessment of rock masses at the Subasi viaduct site, NE, Turkey
Kaya, Ayberk; Bulut, Fikri; Dağ, Serhat
This study investigates the bearing capacity of rock masses and stability of slopes at the Subasi viaduct site which is a part of the improvement project of the Artvin–Hopa government highway between KM 6 + 500 and 13 + 787 in NE Turkey. The geotechnical studies were performed in three stages. Firstly, the bearing capacity of moderately weathered andesitic tuff was evaluated using the empirical equations. Secondly, the major principal stress and vertical displacement due to the viaduct and traffic loadings at the level of foundations were determined by the finite element method (FEM). The vertical displacement value and comparison of bearing capacity and major principal stress show that any problem is not expected at the viaduct site in terms of the bearing capacity. Finally, the stability of slopes at the viaduct site was investigated using kinematic, limit equilibrium, and finite element method-based shear strength reduction analyses methods. It was concluded that no discontinuity controlled failures at the slopes are expected. However, a circular failure is possible to occur at the face slope excavated in highly weathered andesitic tuff. After support application, the long-term stabilization of face slope has been achieved. Consequently, it is suggested that the empirical, analytical, and numerical methods should be combined for a more reliable construction design.
AtıfScopus6WoS5OpenAlex10İncele - MakaleAçık Erişim2018Investigating the relationship between sprint and jump performances with velocity and power parameters during propulsive phase of the loaded-squat jump exercise
Can, İbrahim
The purpose of this study was to investigate the relationship between sprint and jump performance with velocity parameters in the loaded-squat jump exercise (SQ Loaded ). In accordance with this purpose, a total of 13 athletes competing in martial sports have participated in this study voluntarily. In this study, sprint tests, vertical jump (VJ), standing long jump (SLJ) tests and one repetition maximal strength test were applied. In order to determine velocity and power parameters, SQ Loaded exercise was applied by using an external load that corresponds to 40% of body weights of the subjects via an isoinertial velocity transducer (T-Force dynamic measurement system) and values of mean propulsive velocity (MPV), peak velocity (PV), mean propulsive power (MPP) and peak power (PP) were obtained. Descriptive statistics, Spearman correlation analysis and Shapiro-Wilk normality tests were used for data assessment. It has been concluded that there is no statistically significant relation between 10, 20 and 30 meter sprint times and the values of MPV (r=-,332; r=-,375; r=-,446; p>.05 respectively), PV (r=-,058; r=-,118; r=-,165; p>.05 respectively), MPP (r=-,285; r=-,482; r=-,485; p>.05 respectively) and PP (r=-,205; r=-,512; r=-,391; p>.05 respectively) during SQ Loaded exercise. In addition, while no statistically significant relation has been obtained between the VJ and SLJ values of the participants and MPV (r=,496; r =,429; p>.05 respectively) and PV (r=,300; r=,223; p>.05 respectively) values during propulsive stage of SQ Loaded exercise, it has been ascertained that there is a statistically positive and significant relation between the values of MPP(r=,620; r=,580; p>.05 respectively) and PP (r=,678; r=,572; p<.05 respectively). In conclusion, it can be suggested that lifting velocity and power values don’t have a positive effect on short sprint performance; however power values affect the vertical jump and standing long jump performances positively.
AtıfScopus2OpenAlex2İncele - MakaleAçık Erişim2018Scopus SJRQ4Mineral chemistry, whole-rock geochemistry and petrology of Eocene I-type shoshonitic plutons in the Gölköy area (Ordu, NE Turkey)
Temizel, Irfan; Abdioǧlu Yazar, Emel; Arslan, Mehmet; Kaygusuz, Abdullah; Aslan, Zafer
The Eocene intermediate to felsic plutons are widespread in varying sizes and compositions throughout the Eastern Pontides Orogenic Belt in NE Turkey. Of these, two monzonitic bodies (namely the Eriko Tepe and Göl Tepe Plutons) in the Gölköy (Ordu) area, extend nearly in the orientation of NWSE and E-W and were emplaced into the Upper Cretaceous and/or Eocene volcanic and sedimentary rocks. Petrographically, the studied monzonitic plutons are compositionally fine to medium grained monzonite, monzodiorite and subordinate quartz-monzonite. They consist of plagioclase (An35-67), K-feldspar (Or61-96), quartz, clinopyroxene (Wo28-49En35-51Fs10-25), biotite (Mg#: 0.53-0.73) ± hornblende (Mg#: 0.65-0.82), Fe-Ti oxide with monzonitic, poikilitic, perthitic, rare antirapakivi and graphic textures. Mineral thermobarometer estimations imply that the plutons were crystallized in P-T conditions of mid to shallow crustal levels. Petrochemically, these monzonitic plutons show post-collisional, I-type, metaluminous (A/CNK=0.76-0.93) and shoshonitic features. The wholerock major oxide and trace element variations suggest that fractionational crystallization played a significant role in the evolution of these monzonitic plutons. The primitive mantle-normalized trace element patterns of the studied plutons are similar to each other with enrichment in large ion lithophile elements, Th, Ce and negative Nb and Ti anomalies. Moreover, the chondrite-normalized rare earth element plots of the plutons show moderately enriched concave-shaped patterns (LaN/LuN=9.3-12.6) with negative Eu anomalies (EuN/Eu∗=0.69-0.84), all of which imply plagioclase and clinopyroxene ± hornblende fractionations during their evolution. The geochemical data suggest that the monzonitic plutons have evolved from parental magmas derived from the melts of enriched lithospheric mantle, in a post-collisional setting.
AtıfScopus15WoS14OpenAlex14TR Dizin5
İncele - MakaleYalnız künye2018Scopus SJRQ3Automatic Building Extraction from Image and LiDAR Data with Active Contour Segmentation
Akbulut, Zeynep; Özdemir, Samed; Acar, Hayrettin; Karsli, Fevzi
Automatic building extraction is an important topic for many applications such as urban planning, disaster management, 3D building modeling and updating GIS databases. Its approaches mainly depend on two data sources: light detection and ranging (LiDAR) point cloud and aerial imagery both of which have advantages and disadvantages of their own. In this study, in order to benefit from the advantages of each data sources, LiDAR and image data combined together. And then, the building boundaries were extracted with the automated active contour algorithm implemented in MATLAB. Active contour algorithm uses initial contour positions to segment an object in the image. Initial contour positions were detected without user interaction by a series of image enhancements, band ratio and morphological operations. Four test areas with varying building and background levels of detail were selected from ISPRS’s benchmark Vaihingen and Istanbul datasets. Vegetation and shadows were removed from all the datasets by band ratio to improve segmentation quality. Subsequently, LiDAR point cloud data was converted to raster format and added to the aerial imagery as an extra band. Resulting merged image and initial contour positions were given to the active contour algorithm to extract building boundaries. In order to compare the contribution of LiDAR to the proposed method, the boundaries of the buildings were extracted from the input image before and after adding LiDAR data to the image as a layer. Finally extracted building boundaries were smoothed by the Awrangjeb (Int J Remote Sen 37(3): 551–579. https://doi.org/10.1080/01431161.2015.1131868, 2016) boundary regularization algorithm. Correctness (Corr), completeness (Comp) and accuracy (Q) metrics were used to assess accuracy of segmented building boundaries by comparing extracted building boundaries with manually digitized building boundaries. Proposed approach shows the promising results with over 93% correctness, 92% completeness and 89% quality.
AtıfScopus16WoS15OpenAlex16İncele - MakaleAçık Erişim2018Scopus SJRQ3A nutritional evaluation of the berry of a new grape: 'Karaerik' (Vitis vinifera L.)
Kurt, Aynur; Colak, Nesrin; Bengu, Aydin Sükrü; Gundoğdu, Ali; Akpinar, Erdal; Hayirlioglu-Ayaz, Sema; Ayaz, Faik Ahmet
Grape berries are a good source of nutrients and nutraceuticals and have many benefits for human health. Growing interest in the export potential and consumption of a new grape (cv. Karaerik), cultivated as a table grape in Turkey, encouraged us to profile its major nutrient contents from six different locations. Due to its popularity, the nutritional value of this grape berry needs to be investigated to ascertain its potential economic and health benefits. The most abundant sugars in the grape berry were fructose and glucose (peel/whole fruit; averages 236.57 and 127.87, and 183.36 and 108.60 g kg -1 fresh weight, respectively), while the major organic acids were tartaric and malic acids (7.17 and 2.81, and 2.61 and 1.76 g kg -1 fresh weight, respectively). Linoleic acid (peel/whole fruit/seed; 37.14, 33.12 and 57.83%, respectively) was the predominant fatty acid, while potassium (peel/whole fruit/seed; 9331.5, 10226.33 and 5354 μg/g dry weight, respectively) was the predominant mineral, followed by phosphorus (1592.8, 2672 and 3072.67) in the berry. Our results demonstrate that the nutrient components and physicochemical parameters varied significantly among the sampling locations. The grape berry contains considerable quantities of potentially beneficial healthy nutrients worthy of further evaluation.
AtıfScopus7İncele - 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.
AtıfScopus12İncele - MakaleAçık Erişim2018Scopus SJRQ3The effects of 4-vinylcyclohexene diepoxide on the testes of dogs; [Učinci 4-vinilcikloheksen diepoksida na testise pasa.]
Paksoy, Zahid; Kandemi̇r, Fatih M.; Gokhan, Nezihe; Ozkaraca, Mustafa
This study was aimed at investigating the effects of 4-vinylcyclohexene diepoxide (VCD) on testicular tissue in dogs. For this purpose, 30 mongrel male dogs were used and allocated to 5 groups randomly. The first group (n = 6), used as the control, was administered sesame oil by the intraperitoneal route (i/p). The VCD was administered i/p at doses of 80, 160, 240, 320 mg/kg to the second, third, fourth and the fifth groups (n = 6), respectively, once a day for 8 days. The dogs were surgically castrated on the day after the last VCD injection. The testes were removed immediately and fixed in 10% bouine solution. The testes were subjected to routine tissue processing and examined to determine the testicular damage in each testis. When compared to the control group, it was seen that the seminiferous tubule damage increased significantly in the treatment groups. Malondialdehyde levels reached the highest level in the fifth group, while superoxide dismutase, catalase, glutathione peroxidase activity and glutathione levels were higher in the control group (P<0.0001). Nosignificant difference was detected when all the groups were compared with respect to AST, ALT and GGT activities before and after the treatment (P>0.05). Our results showed that VCD may contribute to the sterilization of male dogs.
AtıfScopus4WoS3OpenAlex5İncele - 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.
AtıfScopus22WoS19OpenAlex22İncele - BildiriAçık Erişim2018OBJECT BASED BUILDING EXTRACTION and BUILDING PERIOD ESTIMATION from UNMANNED AERIAL VEHICLE DATA
Comert, Resul; Kaplan, Onur; Honkavaara, E.; Komp, K.; Stilla, U.; Jiang, J.; Zhang, H.; Peled, A.; Soergel, U.; Scaioni, M.
The aim of this study is to examine whether it is possible to estimate the building periods with respect to the building heights in the urban scale seismic performance assessment studies by using the building height retrieved from the unmanned aerial vehicle (UAV) data. For this purpose, a small area, which includes eight residential reinforced concrete buildings, was selected in Eskisehir (Turkey) city center. In this paper, the possibilities of obtaining the building heights that are used in the estimation of building periods from UAV based data, have been investigated. The investigations were carried out in 3 stages; (i) Building boundary extraction with Object Based Image Analysis (OBIA), (ii) height calculation for buildings of interest from nDSM and accuracy assessment with the terrestrial survey. (iii) Estimation of building period using height information. The average difference between the periods estimated according to the heights obtained from field measurements and from the UAV data is 2.86 % and the maximum difference is 13.2 %. Results of this study have shown that the building heights retrieved from the UAV data can be used in the building period estimation in the urban scale vulnerability assessments.
AtıfScopus9OpenAlex10İncele - 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 - MakaleAçık Erişim2018Scopus SJRQ1Indoor and outdoor radon measurements at lung cancer patients’ homes in the dwellings of Rize Province in Turkey
Özen, Songül Akbulut; Celik, Necati; Dursun, Emrehan; Taskın, Halim
In this study, indoor and outdoor radon (222Rn) surveys were carried out in the summer and winter seasons in homes of one hundred lung cancer patients in the year 2013–2014. The aim was to investigate the relationship between radon and cancer patients. Lung cancer patients completed a questionnaire concerning their living environment, various physical parameters and living habits. Pearson correlation and t tests revealed no meaningful results between radon concentrations, on one hand, and environmental and personal living habits, on the other hand. Consequently, the BEIR VI model was adapted and 222Rn exposure was estimated to be responsible for about 12% of the lung cancer incidences in the winter season and around 5% in the summer season in the Rize Province. However, due to the limited number of data and numerous parameters that could lead to lung cancer, the estimations done with the model should be taken very lightly. The annual effective doses due to inhalation of indoor and outdoor 222Rn were estimated to be, respectively, 1.43 and 0.94 mSv y−1. The indoor and outdoor annual effective doses were, respectively, close and below the world annual effective dose (1.3 mSv y−1). At the district level, the indoor annual effective dose equivalent in the İyidere district was 4.52 mSv y−1, which was 3.5 times greater than the world average. The number of patients in the majority of the houses in this district was more than one.
AtıfScopus31WoS27OpenAlex33İncele