Yayınlar
Koleksiyondaki öğeler
- MakaleYalnız künye2016Scopus SJRQ2Influence of CrN Coating on Electrochemical Behavior of Plasma Nitrided Pure Titanium in Bio-simulated Environment
Çelik, Ilhan
Titanium and its alloys are widely used as materials for bio-medical applications, such as implants. However, ions of the alloy can release to the body region and spread into the blood circulation. In this study, plasma nitriding and CrN coating techniques are used in order to overcome the problem of ion release. The objective of this study was to investigate the effects of plasma nitrided pure titanium on the structural properties and corrosion behaviors before and after CrN coating in Ringer's solution at 37 °C. The structural properties were investigated using Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD). A diffusion layer and a compound layer composed of δ-TiN and ε-Ti2N phases were observed on the surface of nitrided pure titanium. Corrosion tests were made for the determination of electrochemical properties with the help of Potentiostat/Galvanostat device. The results show that corrosion behaviors of untreated and treated samples have similar characteristic.
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İncele - MakaleYalnız künye2018Scopus SJRQ1Group decision making with simplified neutrosophic ordered weighted distance operator
Şahin, Rıdvan; Küçük, Gökçe Dilek
Simplified neutrosophic set is a convenient tool proposed for dealing with complex problems; it is effective in providing more data for decision-making process. In this study, we develop a simplified neutrosophic ordered weighted distance operator which combines the neutrosophic distance measures and the ordered weighted average distance in the same formulation. It is a new handy aggregation operator that considers the situations where the input data are represented in simplified neutrosophic numbers, and it also contains diverse distance aggregation operators. Parameterized families of simplified neutrosophic ordered weighted distance operator are handled. Moreover, we establish a new neutrosophic group decision-making method based on the simplified neutrosophic ordered weighted distance operator, which has 2 extended approaches for determining the weights of decision makers and decision attributes in decision-making process, respectively. Finally, an illustrative example demonstrates the application of the proposed method. The effectiveness and advantages of the proposed method are shown by the comparative analysis with existing relative methods.
AtıfScopus12WoS10OpenAlex13İncele - MakaleAçık Erişim2019Scopus SJRQ3The effect of firm growth on brand value: Evidence from brand finance Turkey-100
Gerekan, Bilal; Pehlivan, Abdülkadir; Koçan, Mahmut
A variety of groups are increasingly using brand value for different purposes; thus, a range of consultancy firms calculate, by different methods, and publish brand values annually. The effect of many variables on brand value has been examined previously, but few studies have explored the relationship between brand value and firm growth. This study aims to bridge this gap in the literature, since this relationship is important to maximizing brand value. The research was based on the companies listed in Brand Finance Turkey-100 between 2012 and 2018. Sales, operating income, R&D, and marketing, selling, and distribution (MSD) expenditures were adopted as firm growth indicators, which revealed that: increasing operating income and MSD caused a significant increase in brand value, whereas increasing R&D reduced brand value; and there was no significant relationship between increased sales and brand value.
AtıfScopus3OpenAlex5İncele - MakaleAçık Erişim2016Scopus SJRQ3Investigation of structural and tribological properties of duplex surface treated pure titanium
Çelik, I.; Karakan, M.
Commercial pure titanium (CP-Ti) is used in many engineering fields because of its superior properties such as excellent corrosion resistance, high strength/weight ratio, and biocompatibility. However, it is not available at the desired rate, since the CP-Ti has poor wear resistance. For this reason, many surface treatments have been applied to improve the poor tribological properties of the CP-Ti. In this study, duplex surface treatments, which are the combination of treatments of electroless Ni-B coating and plasma nitriding, were applied on the surfaces of the CP-Ti. Structural properties of the different surfaces of the treated materials were investigated using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Microhardness measurements were made for the determination of mechanical properties and the pin-on-disk wear tests were made to determine the tribological properties. It was observed that poor wear resistance of the CP-Ti was improved with duplex surface treatments. The results showed that surface hardness, friction coefficient, and surface roughness of coated samples were better than of uncoated CP-Ti.
AtıfScopus7WoS5OpenAlex6İncele - 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.
AtıfScopus38WoS32OpenAlex45İncele - MakaleAçık Erişim2016Scopus SJRQ3Determination of stand structure in even-aged oriental beech forests in Turkey; [Determinación de la estructura de rodales de Fagus orientalis coetáneos en Turquía]
Kahriman, Aydın; Altun, Lokman; Güvendi, Engin
This study aimed at developing a stand yield model for even-aged and pure Oriental beech (Fagus orientalis) stands in Sinop Province, located in the north of Turkey. The data used in this study were obtained from 238 sample plots. The sample plots are 24–131 years of stand age range, 19.0–35.9 m of site index range, and 2.2–10.8 of stand density range (relative density index). With the generated equation systems, stand age, site index and density of the three main factors in Oriental beech stands, including the effects of individual, dual and triple factor interactions on the stands were numerically determined. As for even-aged Oriental beech stands, the main stand volume values increase depending on age, site index and density. The number of stems per hectare decreases as the stand grows older, and site index rises; the number, however, increases in parallel with stand density. The current annual volume increment reaches a peak at 30-35 years at all site index groups and density levels, and begins to fall afterwards. Mean annual volume increment peaks up at 65-75 years at all site index classes and density levels, before beginning to decline. The results were in arrangement with the acknowledged growth rules. Stand yield models were assessed as Density-Variable Yield Table used for estimation of the remaining, removal and total stands.
AtıfScopus4WoS3OpenAlex1İncele - MakaleAçık Erişim2017Scopus SJRQ1Diversity and genetic analysis through DArTseq in common bean (Phaseolus vulgaris L.) germplasm from Turkey
Nemlı, Seda; Kaygisiz Aşçioğul, Tansel; Ateş, Duygu; Eşıyok, Dursun; Tanyolaç, Muhammed Bahattin
The common bean (Phaseolus vulgaris L.) is the most consumed food legume in the world and is a major source of dietary protein, carbohydrates, and valuable micronutrients, especially in developing countries. Diversity Arrays Technology (DArTseq), based on genome reduction with restriction enzymes, provides a rapid, high-throughput, and cost-effective tool capable of generating thousands of genotyped single nucleotide polymorphisms (SNPs) for a genome-wide analysis of genetic diversity. In this study, we aimed to characterize common bean accessions using SNPs detected by a DArTseq approach. A total of 43,018 SNPs were identified from 173 common bean accessions, including Andean and Mesoamerican genotypes. After filtering raw and redundant data, a total of 16,366 SNPs were considered for further analyses. According to population structure analysis, the genotypes were roughly divided into 2 gene pools of Andean and Mesoamerican types. Pairwise fixation index (Fst) values were calculated to resolve the differentiation between populations. This study demonstrated that discovering SNPs from the whole genome is a potential resource for identifying naturally diverse accessions and also the information could be used in breeding programs to develop new common bean varieties.
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İncele - MakaleYalnız künye2017Scopus SJRQ1Zircon Lu-Hf isotope systematics and U–Pb geochronology, whole-rock Sr-Nd isotopes and geochemistry of the early Jurassic Gokcedere pluton, Sakarya Zone-NE Turkey: a magmatic response to roll-back of the Paleo-Tethyan oceanic lithosphere
Karsli, Orhan; Dokuz, Abdurrahman; Kandemir, Raif
The early Mesozoic was a critical era for the geodynamic evolution of the Sakarya Zone as transition from accretion to collision events in the region. However, its complex evolutionary history is still debated. To address this issue, we present new in situ zircon U–Pb ages and Lu-Hf isotope data, whole-rock Sr-Nd isotopes, and mineral chemistry and geochemistry data of plutonic rocks to better understand the magmatic processes. The Gokcedere pluton is mainly composed of gabbro and gabbroic diorite. LA-ICP-MS zircon U–Pb dating reveals that the pluton was emplaced in the early Jurassic (177 Ma). These gabbros and gabbroic diorites are characterized by relatively low SiO2 content of 47.09 to 57.15 wt% and high Mg# values varying from 46 to 75. The samples belong to the calc-alkaline series and exhibit a metaluminous I-type character. Moreover, they are slightly enriched in large ion lithophile elements (Rb, Ba, Th and K) and light rare earth elements and depleted in high field strength elements (Nb and Ti). Gabbroic rocks of the pluton have a depleted Sr-Nd isotopic composition, including low initial 87Sr/86Sr ranging from 0.705124 to 0.705599, relatively high εNd (t) values varying from 0.1 to 3.5 and single-stage Nd model ages (TDM1 = 0.65–0.95 Ga). In situ zircon analyses show that the rocks have variable and positive εHf (t) values (4.6 to 13.5) and single-stage Hf model ages (TDM1 = 0.30 to 0.65 Ga). Both the geochemical signature and Sr-Nd-Hf isotopic composition of the gabbroic rocks reveal that the magma of the studied rocks was formed by the partial melting of a depleted mantle wedge metasomatized by slab-derived fluids. The influence of slab fluids is mirrored by their trace-element characteristics. Trace-element modeling suggests that the primary magma was generated by a low and variable degree of partial melting (~5–15%) of a depleted and young lithospheric mantle wedge consisting of phlogopite- and spinel-bearing lherzolite. Heat to melt the mantle material was supplied by the ascendance of a hot asthenosphere triggered by the roll-back of the Paleo-Tethyan oceanic lithosphere. The rising melts were accompanied by fractional crystallization and encountered no or minor crustal contamination en route to the surface. Taking into account these geochemical data and integrating them with regional geological evidence, we propose a slab roll-back model; this model suggests that the Gokcedere gabbroic pluton originated in a back-arc extensional environment associated with the southward subduction of the Paleo-Tethyan oceanic lithosphere during the early Jurassic period. Such an extensional event led to the opening of the northern branch of the Neotethys as a back-arc basin. Consequently, we conclude that the gabbroic pluton was related to intensive extensional tectonic events, which peaked during the early Jurassic in response to the roll-back of Paleo-Tethyan oceanic slab in the final stage of oceanic closure.
AtıfScopus68WoS64OpenAlex68İncele - 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 Dizin1İncele - MakaleAçık Erişim2019Scopus SJRQ1Experimental and numerical studies on axially loaded reinforced square hollow section T-joints
Ozyurt, E.; Das, S.
This paper presents outcomes of experimental and numerical studies completed on unreinforced, collar plate reinforced and doubler plate reinforced Square Hollow Section (SHS)T-joints subjected to axial compressive loading on the brace member. A total of nine full-scale SHS T-joint specimens were fabricated and tested, in which six specimens were reinforced with collar plate and doubler plate. Non-linear finite element (FE)models were developed using finite element code, ABAQUS. Test data was used to validate these FE models. Subsequently, validated FE models were used to conduct an extensive parametric study to investigate the effect of various geometrical parameters of main members and reinforcement plates on the ultimate capacity of reinforced SHS T-joints. The parametric study found that use of both collar and doubler plate reinforcements significantly increase the ultimate capacity of SHS T-joints. Thickness of the reinforcing plate has a positive effect if the thickness of the reinforcing plate is limited to twice the thickness of the chord member. This study, however, found that the capacity of a reinforced SHS T-joint is not dependent on the type of reinforcing plate. The study concludes that the maximum capacity that can be achieved from a reinforced joint is about double the capacity of a similar unreinforced joint. It was found that the Eurocode EN 1993-1-8 overestimates the capacity of reinforced SHS T-joints. Therefore, a new design method for predicting the ultimate capacity of the collar plate and doubler plate reinforced SHS T-joints was developed and this new design method is presented in this paper.
AtıfScopus30WoS27OpenAlex27İncele - MakaleYalnız künye2017Scopus SJRQ1System identification of arch dam model strengthened with CFRP composite materials
Altunisik, A.C.; Gunaydin, M.; Sevim, B.; Adanur, S.
This paper presents the structural identification of an arch dam model for the damaged, repaired and strengthened conditions under different water levels. For this aim, an arch dam-reservoir-foundation model has been constructed. Ambient vibration tests have been performed on the damaged, repaired and strengthened dam models for the empty reservoir (0 cm), 10 cm, 20 cm, 30 cm, 40 cm, 50 cm and full reservoir (60 cm) water levels to illustrate the effects of water levels on the dynamics characteristics. Enhanced Frequency Domain Decomposition Method in the frequency domain has been used to extract the dynamic characteristics. The dynamic characteristics obtained from the damaged, repaired and strengthened dam models show that the natural frequencies and damping ratios are considerably affected from the varying water level. The maximum differences between the frequencies for the empty and full reservoir are obtained as 16%, 33%, and 25% for damaged, repaired and strengthened model respectively. Mode shapes obtained from the all models are not affected by the increasing water level. Also, after the repairing and strengthening implementations, the natural frequencies of the arch dam model increase significantly. After strengthening, between 46-92% and 43-62% recovery in the frequencies are calculated for empty and full reservoir respectively. Apparently, after strengthening implementation, the mode shapes obtained are more acceptable and distinctive compared to those for the damaged model.
AtıfScopus11WoS10OpenAlex4İncele - MakaleYalnız künye2017Scopus SJRQ2Radioactivity measurements and risk assessments of spa waters in some areas in Turkey
Duran, Selcen Uzun; Kucukomeroglu, Belgin; Damla, Nevzat; Taskin, Halim; Celik, Necati; Cevik, Uğur; Ersoy, Hakan
The current study presents the results of the activity of radionuclides in spa waters, and evaluates their radiological influences on the population consuming these waters in the Central and Eastern Black Sea regions of Turkey. Since these waters are used for therapy and consumption purposes unconsciously, their radiological impact on the people was computed by taking into consideration the annual intake through ingestion of 226Ra, 232Th, 40K, 137Cs and 222Rn. The mean activities were estimated to be 11.35 for gross alpha, 6.23 for gross beta, 2.96 for 226Ra, 0.42 for 232Th, 0.069 for 137Cs, 0.19 for 40K, and 267 Bq L–1 for 222Rn, respectively. The estimated effective doses from spa water were found to be 49.77 µSv a–1 (226Ra), 5.95 µSv a–1 (232Th), 0.07 µSv a–1 (137Cs), 0.83 µSv a–1 (40K) and 56.03 µSv a–1 (222Rn). These values were evaluated and compared with related verified values from literature. Also, physico-chemical characterizations of spa water samples considered in the current study were investigated. This study would be useful for consumers and official authorities for the assessment of radiation exposure risk due to usage of the considered spa waters.
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İncele - MakaleAçık Erişim2016Scopus SJRQ2Diversity and ecology of benthic algae in Karagöl Lake, Karagöl-Sahara National Park (Şavşat, Artvin, Turkey)
Akar, Bülent; Şahın, Bülent
Benthic algal flora of Karagöl Lake, its seasonal variation, and the physical and chemical parameters of the water were studied between October 2008 and September 2010. The algal flora consisted of 112 taxa belonging to the divisions Charophyta (41), Chlorophyta (33), Cyanobacteria (18), Euglenozoa (17), Miozoa (2), and Ochrophyta (1). Six desmid taxa found in this research are new records for the freshwater algal flora of Turkey. The qualitative dominance of benthic taxa typical of slightly alkaline and mesotrophic ecosystems was observed. The qualitative and seasonal variations in epipelic taxa analyzed were dependent on the physicochemical characteristics of the water. Water quality was analyzed on the basis of benthic taxa, which are bioindicators. The physicochemical properties of the water are suitable for the development of a rich algal flora (especially desmids). According to the benthic algal composition and indicator species, it is estimated that Karagöl Lake has mesotrophic lake characteristics. This is the first study of benthic algal flora of Karagöl Lake and marks a significant contribution to the knowledge of Karagöl-Sahara National Park’s aquatic biodiversity.
AtıfScopus5WoS3OpenAlex3TR Dizin1İncele - BildiriYalnız künye20163D shoreline extraction using orthophoto and LiDAR data
Bayram, Bulent; Demir, Nusret; Ogurlu, Mustafa; Reis, Hatice Catal; Seker, Dursun Zafer
Shorelines are complex ecosystems and vital socio-economic environments. They may change rapidly due to both natural and human-induced effects. Determination of movements along the shoreline and monitoring of the changes are indispensable for many purposes such as coastline management, agriculture, decision support systems etc. Thus, rapid, up-to-date and accurate information are required to monitor the shorelines. In this study, the Kestel Dam Lake has been selected for evaluation and testing of the methods which will be used for the research project, about shoreline extraction with use of UAV-Based LIDAR data in the region of Terkos-Istanbul, which supported by TUBITAK (The Scientific and Technological Research Council of Turkey) with project nr. 115-718. Kestel Dam is located on the river of Kestel that is constructed for the irrigation purposes, built between 1983 and 1988. Irrigation capacity of dam is about 4077 ha of agricultural areas. The used dataset is LIDAR data which is provided by HGK (Turkish General Command of Mapping). In this study, two different methods are applied with use of LIDAR data, acquired in 2013. One method is mean-shift segmentation and the other is Particle Swarm Optimization Analysis (PSO). The results are both compared with manually created reference vector dataset which is created using orthoimage dataset. The results shows that the developed methods have potential to give success in the research project which will be performed in the region of Terkos which is the study area of the project.
AtıfScopus4İncele - 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 künye2019Scopus SJRQ1Geochronology, geochemistry, and petrology of adakitic Pliocene–Quaternary volcanism in the Şebinkarahisar (Giresun) area, NE Turkey
Yücel, Cem
The Pliocene–Quaternary volcanics in NE Turkey are mainly hornblende–phyric trachyandesites having a narrow range of SiO 2 from 61.88 to 63.00 wt.% and exhibiting adakitic signatures with their Na 2 O (3.67–4.27 wt.%), Al 2 O 3 (16.19–16.80 wt.%), Y (14.1–16.5 ppm) contents and K 2 O/Na 2 O (0.87–1.12), Sr/Y (44.24–54.90), and La/Yb (36.80–43.88) ratios. Plagioclases as the main mineral phases show a wide range of compositions, and weak normal and reverse zoning. Hornblendes are generally edenite and pargasite (Mg#: 0.39–0.74). Clinopyroxenes are augite (Mg#: 0.58–0.76). Biotites have Mg# ranging from 0.45 to 0.66. The textural and compositional variations indicate disequilibrium crystallization possibly arising from magma mixing. The U–Pb zircon dating of the adakitic volcanics yielded 3.4–1.9 Ma. The studied rocks display moderate light rare earth element /heavy rare earth element ratios and enrichment in the lithophile element and depletion in high field strength element, implying that the parental magmas were derived from mantle sources previously enriched by slab-derived fluids and/or subducted sediments. The crystallization temperature and pressure estimations based on the clinopyroxene thermobarometry range from 1144 to 1186°C and from 3.92 to 7.97 kbar, respectively. Hornblende thermobarometry, oxygen fugacity, and hygrometer calculations yielded results as 908–993°C at a pressure of 2.87–5.22 kbar, water content of 4.4–8.4 wt.%, and relative oxygen fugacity (ΔNNO log units) of −0.6 to 0.9, respectively. Biotite thermobarometry suggests relatively higher oxygen fugacity conditions (10 –13.33 to 10 –17.60 ) at temperatures of 676–819°C and at pressures from 1.15 to 1.76 kbar. In the light of the obtained data and modelling, it can be concluded that the magmas of the adakitic volcanics were derived from enriched mantle source through relatively higher partial melting and experienced magma mixing with melts at the crustal level. Additionally, the fractional crystallization and assimilation-fractional crystallization processes may have played an important role during the evolution of the studied volcanics.
AtıfScopus28WoS27OpenAlex27İncele - MakaleAçık Erişim2016Scopus SJRQ3Existence and uniqueness theorems for sequential linear conformable fractional differential equations
Gökdoğan, Ahmet; Ünal, Emrah; Çelik, Ercan
Recently, a new definition of fractional derivative called as the conformable fractional derivative which based on limits introduced by Khalil et al (2014). Later, Abdeljawad (2015) improved these definitions and gave the basic concepts in this new fractional calculus. In this paper, we generalize Abel's formula and Wronskian determinant definition and establish existence and uniqueness theorems for sequential linear conformable fractional differential equations.
AtıfScopus27WoS26OpenAlex40İncele - MakaleYalnız künye2016Scopus SJRQ1U–Pb zircon chronology and petrogenesis of Carboniferous plutons in the northern part of the Eastern Pontides, NE Turkey: Constraints for Paleozoic magmatism and geodynamic evolution
Kaygusuz, Abdullah; Arslan, Mehmet; Sipahi, Ferkan; Temizel, İrfan
Numerous intrusive rocks of varying ages and compositions exist in the Paleozoic to Tertiary periods in the Eastern Pontides. Carboniferous intrusive rocks are commonly observed in the southern part of the Eastern Pontides. The nature of the rocks in the northern part of the region has not been determined because of Upper Cretaceous and Tertiary volcano-sedimentary units. Whole-rock geochemical, isotopic and geochronological data obtained from five different mapped granitoid bodies located in the northern part of the Eastern Pontides allow for the proper reconstruction of Carboniferous magmatism and the geodynamic evolution of the region. According to laser ablation ICP-MS U–Pb zircon dating, the Özdil, Soğuksu, Seslikaya, Kızılağaç and Şahmetlik plutons have similar 206Pb/238U vs. 207Pb/235U concordia ages of 340.7 ± 1.8 Ma and 323.1 ± 1.5 Ma, 348.4 ± 1.6 Ma, 335.4 ± 1.4 Ma, 337.2 ± 0.6 Ma and 334.5 ± 1.4 Ma, respectively. The aluminium saturation index (ASI) values of all of the samples from the plutons are between 1.0 and 1.32, which indicate peraluminous melt compositions. The plutons have SiO2 contents between 59 and 79 wt.% and show low- to high-K calc-alkaline characteristics. The plutons are enriched in large-ion lithophile and light rare earth elements and are depleted in high-field strength elements. Chondrite-normalized rare earth element patterns are characterized by concave-upward shapes and pronounced negative Eu anomalies, with LaCN/YbCN = 1.9–46.8 and EuCN/Eu* = 0.19–1.76. The studied plutons show considerable variations in 87Sr/86Sr(i) (0.70255 to 0.71006) and εNd(i) values (− 4.8 to − 7.1), as well as Nd model ages (1.15 to 2.47 Ga). The Pb-isotopic ratios are 206Pb/204Pb = 17.11–18.60, 207Pb/204Pb = 15.58–15.64 and 208Pb/204Pb = 36.95–38.62. The crystallization temperatures of the melts range from 676 to 993 °C, as determined by zircon and apatite saturation thermometry. These data suggest that the Carboniferous granitic magmas were produced by the partial melting of meta-mafic to meta-felsic lower crustal source rocks, with minor contributions from the mantle. Collectively, these rocks represent a late stage of Hercynian magmatism in the northern part of the Eastern Pontides.
AtıfScopus90WoS84OpenAlex97İncele - MakaleYayıncıda açık erişim2016Scopus SJRQ1Modeling deformation modulus of a stratified sedimentary rock mass using neural network, fuzzy inference and genetic programming
Alemdag, S.; Gurocak, Z.; Cevik, A.; Cabalar, A.F.; Gokceoglu, C.
This paper investigates a series of experimental results and numerical simulations employed to estimate the deformation modulus of a stratified rock mass. The deformation modulus of rock mass has a significant importance for some applications in engineering geology and geotechnical projects including foundation, slope, and tunnel designs. Deformation modulus of a rock mass can be determined using large scale in-situ tests. This large scale sophisticated in-situ testing equipments are sometimes difficult to install, plus time consuming to be employed in the field. Therefore, this study aims to estimate indirectly the deformation modulus values via empirical methods such as the neural network, neuro fuzzy and genetic programming approaches. A series of analyses have been developed for correlating various relationships between the deformation modulus of rock mass, rock mass rating, rock quality designation, uniaxial compressive strength, and elasticity modulus of intact rock parameters. The performance capacities of proposed models are assessed and found as quite satisfactory. At the completion of a comparative study on the accuracy of models, in the results, it is seen that overall genetic programming models yielded more precise results than neural network and neuro fuzzy models.
AtıfScopus113WoS110OpenAlex108İncele - 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
