Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Uzun, Sevda(66)
- Merdan, Mehmet(56)
- Duran, Celal(50)
- Ozdes, Duygu(47)
- Kaygusuz, Abdullah(42)
- Demir, Selim(37)
- Turan, Ibrahim(37)
- Ashyralyyev, Charyyar(34)
- Dokuz, Abdurrahman(33)
- Araz, Onur(31)
- Öztürk, Serkan(31)
- Sipahi, Ferkan(30)
- Kandemir, Raif(28)
- Arslan, Mehmet(27)
- Karsli, Orhan(27)
- Kulakaç, Nurşen(26)
- Baltacı, Cemalettin(25)
- Gücer, Mehmet Ali(25)
- Kurt, Kemal(25)
- Maden, Nafiz(25)
- Ozturk, Samet(25)
- Topal, Fevzi(25)
- Baltaci, Cemalettin(24)
- Yücel, Cem(24)
- Aliyazicioglu, Yuksel(23)
- Bayrakdaroglu, Serdar(23)
- Kankal, Murat(23)
- Peker, Iskender(23)
- Yolcu, Halil(23)
- Reis, Hatice Catal(21)
- Topal, Meryem(21)
- Vural, Alaaddin(21)
- Aydin, Aydanur(20)
- Aydin, Faruk(20)
- Bayraktar, Alemdar(20)
- Kurnaz, Muammer(20)
- Çelik, Necati(20)
- Ürkek, Bayram(20)
- Cakir, Tufan(18)
- Günen, Mehmet Akif(18)
Yayınlar
- Derleme MakaleAçık Erişim2018Scopus SJRQ1Late Cretaceous arc igneous activity: the Eğrikar Monzogranite example
Sipahi, F.; Kaygusuz, A.; Saydam Eker, Ç.; Vural, A.; Akpınar, İ.
The geochemical and Sr–Nd–Pb isotope properties, as well as the Laser Ablation Inductively Coupled Plasma and Mass Spectrometry (LA-ICP-MS) U–Pb zircon age, of Eğrikar Monzogranite in the eastern Pontides, are primarily investigated in this study with the aim of determining its magma source and geodynamic evolution. The U–Pb zircon age obtained from Eğrikar Monzogranite is 78 ± 1.5 Ma, thereby reflecting the age of monzogranite. The I-type Eğrikar Monzogranite comprises quartz, plagioclase (An35–45), orthoclase, muscovite, and biotite. The geochemical analyses of the Eğrikar Monzogranite indicate being medium K calc-alkaline, peraluminous, and resembling magmatic arc granite. The Eğrikar Monzogranite is enriched in large ion lithophile elements and light rare earth elements relative to high field strength elements. Chondrite-normalized rare earth element patterns have concave upward shapes (LaN/YbN 2.47–8.58) with pronounced negative Eu anomalies (EuN/Eu* = 0.29–0.65). Initial εNd(i) values vary between 1.85 and 2.18 and initial 87Sr/86Sr values between 0.7048 and 0.7067. Fractionation of plagioclase, hornblende, and apatite played an important role in the evolution of Eğrikar Monzogranite. The crystallization temperatures of the melts ranged from 770°C to 919°C based on zircon and apatite saturation temperatures. The geochemical and isotopic data suggest being generated by the partial melting of mafic lower crustal sources.
AtıfScopus38WoS32OpenAlex45
İncele - MakaleAçık Erişim2018Scopus SJRQ3A rapid and sensitive spectrofluorometric method for the determination of au(III) based on fluorescence quenching of a 1,3,5-triphenyl-2-pyrazoline
Başoğlu, Aysel; Ocak, Ümmühan; Fandakli, Seda; Yayli, Nurettin
A simple, rapid, sensitive, and low-cost spectrofluorometric method was developed for the determination of Au(III) using 5-(2,3-dimethoxyphenyl)-3-(4-methoxyphenyl)-1-phenyl-4,5-dihydro-1H-pyrazole (L) in ethanol/water. The method is based on the change in the fluorescence intensity at 464 nm after excitation at 355 nm as a result of the reaction between the ligand and Au(III). The fluorescent emission of ligand at 464 nm decreased with the increasing of Au(III) concentration. The ligand concentration, pH effect, response time, and effect of foreign ions were determined. From the results of fluorescence titration experiments, it was found that the ligand (1 × 10−7 M) was selective and sensitive to Au(III) in EtOH-H2 O (1:1, v/v, phthalate buffer, pH 4.0). The calibration curve showed good linearity in the concentration range of 17.4–237.6 µg L−1 Au(III). The limits of detection and quantification were 5.2 and 17.4 µg L−1 Au(III) with a response time of 1 min, respectively. Satisfactory accuracy was obtained for standard reference material (CRM-SA-C Sandy Soil C). The proposed method was successfully applied to the determination of Au(III) in tap water, sea water, and stream water samples, and high levels of recovery were obtained.
AtıfScopus4WoS4OpenAlex5TR Dizin1
İncele - MakaleAçık Erişim2018Scopus SJRQ3Antioxidant properties and protective effect of Turkish propolis on t-BHP-induced oxidative stress in foreskin fibroblast cells
Misir, Sema; Aliyazicioglu, Yuksel; Demir, Selim; Turan, Ibrahim; Yaman, Serap Ozer; Deger, Orhan
Objective: Propolis is an important bee product, rich in polyphenolic compounds. It has antitumoral, antioxidant, antimutagenic, and other useful activities. Biological activities of propolis are generally attributed to its substance of polyphenolic compounds. The aim of this study was to investigate the in vitro antioxidant properties and reduction amount of intracellular reactive oxygen species (ROS) in human normal foreskin fibroblast cells by Turkish propolis ethanolic extract (EEP). Method: Total phenolic and flavonoid contents, reducing power, radical scavenging capacity, and iron chelating activity of EEP were determined using spectrophotometric methods. Intracellular ROS levels were determined by spectrofluorometric analysis with CM-H2 DCFDA. Results: Our results indicated that antioxidant activity was correlated with the higher total phenolic and flavonoid contents of EEP. The generated ROS levels were significantly decreased by EEP compared to only t-BHP group. Conclusion: Ethanolic propolis extract may be evaluated as a potency antioxidant resource and/or a novel natural agent in food and drug industries.
AtıfScopus11WoS15OpenAlex16İncele - MakaleYalnız künye2018Scopus SJRQ2The relationships between performance traits and the bGH/Alu i and Pit-1/ Hinf I polymorphisms in Holstein cows
Ozdemir, Memis; Topal, Mehmet; Aksakal, Vecihi
Progress in genetic selection in livestock can be increased by marker asisted selection. The identification of favorable genetic markers is one of the most important stages in marker-asisted selection. In this study, it was aimed to determine the effects of the bGH/AluI and Pit-1/HinfI polymorphisms on the production traits of organic reared cows. Genotyping was performed on total 245 Holstein cows, n=181 for Pit-1 gene and n=186 for bGH gene. Milk yields and some reproduction traits analyzed by analysis of variance using the general linear model procedure, and 703 production records from cows were used to. The results showed that neither the Pit-1/Hinf I nor bGH/Alu I polymorphisms affect the tested milk traits (p>0.05).
AtıfScopus13WoS12OpenAlex11İncele - MakaleYalnız künye2018Scopus SJRQ2Ambient Vibration-Based System Identification of a Medieval Masonry Bastion for Health Assessment using Nonlinear Analyses
Altunişik, Ahmet Can; Genç, Ali Fuat; Günaydin, Murat; Adanur, Süleyman; Yesevi Okur, Fatih
Earthquakes have underlined the need for health monitoring and safety assessment of engineering structures in general and especially historical heritage. These structures can be exposed to many different loads such as earthquake and wind that may cause the deterioration and loss of structural integrity. In this study, ambient vibration-based system identification of Zaǧanos Bastion is carried out for health assessment using linear and nonlinear analyses. 3D finite element analyses of the bastion are performed using relievo drawings and analytical dynamic characteristics are obtained. Ambient vibration tests are conducted on the bastion and experimental dynamic characteristics such as natural frequencies, mode shapes and damping ratios are determined. Enhanced Frequency Domain Decomposition Method in the frequency domain and Stochastic Subspace Identification Method in the time domain are used to extract the experimental dynamic characteristics. Maximum differences are minimized using some uncertain parameters to obtain the updated finite element model. Linear and nonlinear time history analyses are carried out using 1999 Kocaeli earthquake ground motion record to display the maximum displacements, stresses and local damage regions with detail. This study suggests that minor damage at the connection points and exterior surface will sustain under destructive earthquakes.
AtıfScopus14WoS14OpenAlex12İncele - MakaleYalnız künye2018Scopus SJRQ3Prediction of the antimicrobial activity of walnut (Juglans regia L.) kernel aqueous extracts using artificial neural network and multiple linear regression
Kavuncuoglu, Hatice; Kavuncuoglu, Erhan; Karatas, Seyda Merve; Benli, Büsra; Sagdic, Osman; Yalcin, Hasan
The mathematical model was established to determine the diameter of inhibition zone of the walnut extract on the twelve bacterial species. Type of extraction, concentration, and pathogens were taken as input variables. Two models were used with the aim of designing this system. One of them was developed with artificial neural networks (ANN), and the other was formed with multiple linear regression (MLR). Four common training algorithms were used. Levenberg–Marquardt (LM), Bayesian regulation (BR), scaled conjugate gradient (SCG) and resilient back propagation (RP) were investigated, and the algorithms were compared. Root mean squared error and correlation coefficient were evaluated as performance criteria. When these criteria were analyzed, ANN showed high prediction performance, while MLR showed low prediction performance. As a result, it is seen that when the different input values are provided to the system developed with ANN, the most accurate inhibition zone (IZ) estimates were obtained. The results of this study could offer new perspectives, particularly in the field of microbiology, because these could be applied to other type of extraction, concentrations, and pathogens, without resorting to experiments.
AtıfScopus39WoS33OpenAlex46
İncele - MakaleYayıncıda açık erişim2018Scopus SJRQ1Choosing safe and suitable bicycle routes to integrate cycling and public transport systems
Saplıoğlu, M.; Aydın, M.M.
Bicycle utilization has become an important transportation mode in various cities during the past decade. It has brought a rapid growth as an important transport mode in many countries by providing several benefits for traffic, health and cost. However, the growing in bicycle utilization demand causes many problems such as safety, effectiveness etc. For this reason, other effective parameters on urban transport should be considered when planning new safe bicycle paths in the spatial platform. In this study, it was aimed to examine all these negative and positive effective parameters on safety and choice while integrating cycling with a public transport (bus link) system. To determine effective parameters on route choice, a Questionnaire Survey (QS) was carried out on 460 participants who are cycling for a long time in Isparta City/Turkey. It was obtained from the QS that Accident Prone Areas (APA) are the most important factor on cycling and public transport integration. The other parameters are determined as Bus Lane (BL), Road Side Car Park (RSCP), Bicycle Parks (BP), Road Grade (RG), Signalization (S), Traffic Capacity (TC), Connected Bike Lane (CBL) and Separated Bike Lane (SBL) according to their importance. In order to determine safer and serviceable bicycle routes selection problem, accident-prone locations (using Accident Reports and Geographic Information Systems-GIS), bus lines and survey data has been used in GIS. Also, a multi-criteria decision making approach Analytic Hierarchy Process (AHP) method is implemented to analyze survey data and decide effective parameters on safer and serviceable bicycle routes. It was found that safer and serviceable bicycle routes can be determined by the utilization of QS, GIS and AHP methods with together. Also, it was concluded that Accident Prone Areas, Bus Lanes and Road Side Car Parks are the most important factors while integrating cycling with a public transport system.
AtıfScopus66WoS62OpenAlex79İncele - MakaleYalnız künye2018Scopus SJRQ3Quality properties of wheat breads incorporated with dried sourdoughs produced with different fermentation and drying methods
Hendek Ertop, M.; Ilter, S.M.; YilMaz, F.; BaltaCi, C.; Gündogdu, A.
The aim of this study was to evaluate the effect of the dried sourdoughs produced with two different fermentation methods [Spontaneous fermentation(SPF) and starter of lactic acid bacteria-added fermentation(STF)], and three different drying methods (Drying in oven;DO, Freeze drier;DFD, and Spray drier;DSD) on various quality properties of the wheat bread. The bread samples prepared by addition of the dried sourdoughs at the rates of 3 %, 6 % and 12 %, and control bread prepared without sourdough were compared in terms of bioactivity, shelf life, physicochemical and sensory properties. The addition of the dried sourdough affected the specifc volume, pH and acidity of the bread samples signifcantly (p < 0.05), and a slow down moisture loss occurred during shelf life.The a*value of crust, antioxidant activity, and sensory properties were improved compared to the control bread. The use of dried sourdough at the rate of 12 % gave the most effective results. When the fermentation and drying methods were evaluated together, the combinations of SPF/DO, SPF/DFD and STE/DSD gave the best results.
AtıfScopus17WoS13OpenAlex19İncele - MakaleYalnız künye2018Scopus SJRQ4Antioxidant potential of rosehip seed extract in stabilisation of flaxseed oil
Ilyasoglu, H.
The aim of this study was to evaluate the usage of rosehip seed powder (RSP) extract in flaxseed oil to retard lipid oxidation. The acetone extract of the RSP (500 mg kg-1; 1000 mg kg-1) was used. Synthetic antioxidant BHT (200 mg kg-1) was added into the flaxseed oil to evaluate the antioxidant potential of the RSP extract. The peroxide value (PV), TBARS value, and p-anisidine value (p-AV) of the flaxseed oil were analysed during 12 days of storage. The total oxidation (TOTOX) value was also calculated. The sample with the RSP (500 mg kg-1; 1000 mg kg-1) generally showed lower PV, p-AV, and TOTOX value than the control sample and sample with the BHT. These results indicated that the RSP may be used in edible oils to prevent lipid oxidation as a source of natural antioxidants.
- BildiriAçık Erişim2018Thermal modeling and verification of pv module temperature and energy yield using outdoor measurements for Ankara, Turkey
Tuncel, Bilge; Akinoglu, Bulent G.; Ozden, Talat; Balog, Robert S.
Ankara is in the Central Anatolia region of Turkey where the climate is dry-continental with an annual solar insolation of around 1750 kWh/m 2 . In the transition to renewable energy, detailed analyses are required to ensure effective and economic utilization of the available solar resource. An essential part of these analyses is to calculate expected energy yield. For photovoltaic (PV) systems, this includes the effect of temperature on the PV efficiency, which determines the power yield of the PV modules. In this study, a first-principles thermal modeling approach is improved by adding the speed and direction of wind across the PV module into a forced convection term as well as including the temperature dependency of the module conversion efficiency. The analytical model is based on the principle of conservation of energy and uses meteorological data that are readily available from most state meteorological services. The mathematical analysis is suitable to predict the performance of a proposed PV installation without the time and expense of installing and monitoring a pilot system. The mathematical model is compared against measured data from the METU-GUNAM Outdoor Test Facility in Ankara to validate the methodology. Preliminary analyses showed that the model performs well especially during sunrise and sunsets shoulders of the diurnal cycle with a deviation of only a few W/m 2 for the electrical power yield and about 2°C for the module temperature. However, these deviations could become as large as 12 W/m 2 and 8°C at solar noon which suggests that the model still requires further improvement. In general, this error was found to be less that obtained by using basic explicit correlation methods and offers the advantage that it can be used for other geographical environments for which insolation and meteorological data is available without needing to construct a test-site.
AtıfScopus6WoS4OpenAlex6İncele - MakaleYalnız künye2018Scopus SJRQ1Galileo satellite data contribution to GNSS solutions for short and long baselines
Yalvac, S.; Berber, M.
GALILEO (Europe's Global Navigation Satellite System) is going full speed ahead to achieve full constellation by 2020. Since GALILEO is currently an emerging system, the contribution of these satellites to GNSS (Global Navigation Satellite System) solutions needs to be investigated. For this purpose, GNSS data collected at three IGS (International GNSS Service) MGEX (Multi GNSS Experiment) stations are analyzed. For the analyses, GPS (Global Positioning System) only, GLONASS (Russia's Global Navigation Satellite System) only, GALILEO-only and combined solutions are tested and also effect of baseline length is examined. The results indicate that compared to GPS, GLONASS and ALL (GPS + GLONASS + GALILEO) solutions, GALILEO results vary greatly. When GALILEO observations are combined with other observations, the precision goes down. That is to say, for short baseline solution, GALILEO results fluctuate around 1 cm in the horizontal plane and in the vertical plane variations are mostly within 3–5 cm. For long baseline solution, GALILEO results are going up and down in the horizontal between 2 and 3 cm and in the vertical roughly 10 cm. In terms of accuracy, for short baseline solution, GALILEO-only solution is close to GPS-only solution; yet, we cannot say the same thing for long baseline solution.
AtıfScopus13WoS11OpenAlex12İncele - BildiriAçık Erişim2018Well-posedness of Neumann-type elliptic overdetermined problem with integral condition
Ashyralyyev, Charyyar; Çay, Aysel; Ashyralyev, A.; Sadybekov, M.; Lukashov, A.
The current paper is devoted to overdetermined elliptic problem with integral condition for derivatives. This overde-termined problem is converted to auxiliary nonlocal boundary value problem (ANBVP) with integral boundary condition. Well-posedness of abstract problem is established. Then, obtained results are used to obtain stability inequalities for solution of three Neumann-type inverse elliptic problems with integral condition to multidimensional differential equation.
AtıfScopus14WoS9OpenAlex16İncele - MakaleYalnız künye2018Scopus SJRQ1The Fabrication and MOSFET-Only Circuit Implementation of Semiconductor Memristor
Babacan, Yunus; Yesil, Abdullah; Gul, Fatih
In this paper, a ZnO-based semiconductor thin film memristor (300 nm in thickness) device is fabricated using metallic top and bottom electrodes by direct-current reactive magnetron sputter. The memristive characteristics of the device were completed by time-dependent current-voltage (I-V-t) measurements, and the typical pinched hysteresis I-V loops of the memristor were observed. This paper is continued with the designing memristor emulator circuit, which has only four MOS transistors. The proposed circuit is suitable both for emulating the fabricated memristor and for using general memristor-based applications. Any circuit blocks such as a multiplier or active element are not used in the circuit to obtain memristive characteristics. All results of the proposed memristor emulator circuit are compatible with general characteristics of the fabricated semiconductor device. The MOSFET-based proposed memristor emulator circuit is laid out in the Analog Design Environment of Cadence Software using 180-nm TSMC CMOS process parameters and its layout area is 366 μm2. So as to show its performance, the dependences of the operating frequency and process corner as well as effects of radical temperature changes have been investigated in the simulation results section.
AtıfScopus94WoS77OpenAlex98İncele - BildiriAçık Erişim2018Performance and degradation analyses of two different pv modules in central anatolia
Ozden, Talat; Akinoglu, Bulent G.; Kurtz, Sarah
Ankara (latitude: around 40°N) is in Central Anatolia and the climate is dry continental. Due to the rapid transition to renewable energy policies of Turkey it is now a must to complete truthful feasibility analyses for solar power systems countrywide. Long term performance and degradation analyses have been carried out by the authors for three different arrays and many research results appearing in the literature are summarized. Present research analyzes the outdoor testing results of two PV modules monthly data. One of the modules has multi crystalline silicon (Poly-Si) cells and the other is thin film silicon (amorphous Si / microcrystalline Si tandem structure - a-Si/μc-Si) cells. The results showed that in five years the average yearly efficiency decreases from 14% to 11% for Poly-Si (14.72% is the nameplate Standard Test Condition (STC) efficiency) and from 8% to 6% for thin film modules (9.15% is STC efficiency). Our calculations are based on measured solar global-horizontal irradiance from which we calculated plane-of-array irradiation using an anisotropic sky model. We present the details of these analyses and degradation rates for the two types of modules to be used in long term feasibility analyses.
AtıfScopus11OpenAlex10İncele - MakaleYayıncıda açık erişim2018Scopus SJRQ2Finite difference method for bitsadze-samarskii type overdetermined elliptic problem with dirichlet conditions
Ashyralyyev, Charyyar; Akyuz, Gulzipa
In this paper, we apply finite difference method to Bitsadze-Samarskii type overdetermined elliptic problem with Dirichlet conditions. Stability, coercive stability inequalities for solution of the first and second order of accuracy difference schemes (ADSs) are proved. Then, established abstract results are applied to get stable difference schemes for Bitsadze-Samarskii type overdetermined elliptic multidimensional differential problems with multipoint nonlocal boundary conditions. Finally, numerical results with explanation on the realization in two dimensional and three dimensional cases are presented.
AtıfScopus10WoS7OpenAlex11İncele - BildiriAçık Erişim2018Stress Analysis and Fatigue Behaviour of PTFE-Bronze Layered Journal Bearing under Real-Time Dynamic Loading
Duman, M.S.; Kaplan, E.; Cuvalci, O.; Hamamci, M.; Gocer, A.; Karamis, M.B.; Nair, F.; Savas, S.
The present paper is based on experimental studies and numerical simulations on the surface fatigue failure of the PTFE-bronze layered journal bearings under real-time loading. 'Permaglide Plain Bearings P10' type journal bearings were experimentally tested under different real time dynamic loadings by using real time journal bearing test system in our laboratory. The journal bearing consists of a PTFE-bronze layer approximately 0.32 mm thick on the steel support layer with 2.18 mm thick. Two different approaches have been considered with in experiments: (i) under real- time constant loading with varying bearing widths, (ii) under different real-time loadings at constant bearing widths. Fatigue regions, micro-crack dispersion and stress distributions occurred at the journal bearing were experimentally and theoretically investigated. The relation between fatigue region and pressure distributions were investigated by determining the circumferential pressure distribution under real-time dynamic loadings for the position of every 10° crank angles. In the theoretical part; stress and deformation distributions at the surface of the journal bearing analysed by using finite element methods to determine the relationship between stress and fatigue behaviour. As a result of this study, the maximum oil pressure and fatigue cracks were observed in the most heavily loaded regions of the bearing surface. Experimental results show that PTFE-Bronze layered journal bearings fatigue behaviour is better than the bearings include white metal alloy.
AtıfScopus4WoS5OpenAlex5İncele - MakaleYalnız künye2018Scopus SJRQ1Experimental study on cement-treated and untreated RAP blended bases: Cyclic plate loading test
Seferoğlu, Ayşegül Güneş; Seferoğlu, Mehmet Tevfik; Akpinar, Muhammet Vefa
The asphalt surrounding the reclaimed asphalt pavement (RAP) aggregates decrease the performance characteristics of road layers. RAP material increases the permanent deformation potential of road layers under the traffic load. In this study, the performances of RAP-VA (Virgin aggregate) mixtures was tested using cyclic plate loading test by adding pozzolanic cement into mixtures in order to use RAP material at the rate of 100% and to minimize the permanent deformation in plant-mix base courses (PBC). The permanent surface deformations of base course were measured at different points throughout 100 loading cycles and all of the measurements were compared to that of base course prepared from 100% VA. The effect of RAP/cement rate of mixtures on the permanent deformations was examined and it was determined that the increase in RAP rate increased the permanent deformations but cement significantly decreased it. Moreover, considering the material costs of mixtures, the cost analysis was performed and the profit margins that using RAP and cement offers to constructors were computed.
AtıfScopus24WoS22OpenAlex25İncele - MakaleAçık Erişim2018Scopus SJRQ4Single production of the excited muons at the SPPC-based ultimate μp collider
Cąliskan, Abdullatif
Single production potential of the excited muons at the SPPC-based ultimate muon-proton collider with center-of-mass energy of 116.6 TeV was analyzed. We calculated the production cross-sections and the decay widths of the excited muons with the process of μp → μX → γμX. We obtained the normalized transverse momentum and pseudorapidity distributions of the final-state particles to attain the kinematical cuts for the discovery of the excited muons. With these cuts, we determined the mass limits. It was shown that the discovery limits on the mass of the excited muons are 19.6 and 10.1 TeV for λ = mμ and λ=50 TeV, respectively.
AtıfScopus3WoS3OpenAlex4TR Dizin2İncele - MakaleYalnız künye2018Scopus SJRQ3Modeling of Co(II) adsorption by artificial bee colony and genetic algorithm
Öztürk, Nurcan; Sentürk, Hasan Basri; Gündogdu, Ali; Duran, Celal
In this work, it was investigated the usability of artificial bee colony (ABC) and genetic algorithm (GA) in modeling adsorption of Co(II) onto drinking water treatment sludge (DWTS). DWTS, obtained as inevitable byproduct at the end of drinking water treatment stages, was used as an adsorbent without any physical or chemical pre-treatment in the adsorption experiments. Firstly, DWTS was characterized employing various analytical procedures such as elemental, FT-IR, SEM-EDS, XRD, XRF and TGA/DTA analysis. Then, adsorption experiments were carried out in a batch system and DWTS's Co(II) removal potential was modelled via ABC and GA methods considering the effects of certain experimental parameters (initial pH, contact time, initial Co(II) concentration, DWTS dosage) called as the input parameters. The accuracy of ABC and GA method was determined and these methods were applied to four different functions: quadratic, exponential, linear and power. Some statistical indices (sum square error, root mean square error, mean absolute error, average relative error, and determination coefficient) were used to evaluate the performance of these models. The ABC and GA method with quadratic forms obtained better prediction. As a result, it was shown ABC and GA can be used optimization of the regression function coefficients in modeling adsorption experiments.
AtıfScopus5WoS4OpenAlex4İncele - MakaleAçık Erişim2018Scopus SJRQ1Resistance of Axially Loaded T- and X-Joints of Elliptical Hollow Sections at Elevated Temperatures – A Finite Element Study
Ozyurt, E.; Wang, Y.C.
This study presents the results of a numerical study to develop a method to calculate the static strength of welded Elliptical Hollow Section (EHS) joints at elevated temperatures. Extensive numerical simulations using the non-linear finite element package, ABAQUS v6.14–1 on EHS T- and X-joints under brace axial compression or tension and pre-stress in chord member with different type of joint orientations at elevated temperatures over a wide range of diameter ratio have been conducted. The adjustments required to be made to the equations of joint resistance under ambient temperature conditions for estimating joint resistance at elevated temperature conditions are investigated in this study. The FE simulation results have been compared with the calculation results of a number of existing methods at ambient temperature. It has been found that the method proposed by Packer et al. gives the best agreement with the authors' simulation results at ambient temperature. At elevated temperatures, for T- and X- joints with braces in compression welded to the wide sides of chords, replacing the ambient temperature yield strength of steel by the elevated temperature value in the current design method overestimates the ultimate load carrying capacity of axially loaded EHS T- and X-joints due to inability of the ambient temperature calculation equations to take into consideration EHS flattening at high temperatures. For these cases, it is recommended to calculate the joint strength reduction factor at elevated temperatures according to the Young's modulus of steel.
AtıfScopus21WoS18OpenAlex22İncele