Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Kaygusuz, Abdullah(35)
- Sipahi, Ferkan(35)
- Karsli, Orhan(34)
- Dokuz, Abdurrahman(30)
- Duran, Celal(30)
- Kandemir, Raif(29)
- Ozdes, Duygu(28)
- Maden, Nafiz(27)
- Uzun, Sevda(27)
- Merdan, Mehmet(26)
- Vural, Alaaddin(26)
- Öztürk, Serkan(25)
- Araz, Onur(24)
- Kulakaç, Nurşen(24)
- Ashyralyyev, Charyyar(23)
- Yildiz, Salih(23)
- Yilmaz, Ozgur(23)
- Doğan, Kadir Caner(21)
- Arslan, Mehmet(20)
- Aydin, Faruk(20)
- Doğru, Bülent(20)
- Bayraktar, Alemdar(19)
- Kankal, Murat(19)
- Ayaydin, Hasan(18)
- Baltaci, Cemalettin(18)
- Yolcu, Halil(18)
- Cakir, Tufan(17)
- Cengiz, Ekrem(17)
- Demir, Selim(17)
- Gücer, Mehmet Ali(17)
- Akaryali, Enver(16)
- Artan, Seyfettin(16)
- Hayaloğlu, Pınar(16)
- Kaya, Afşin Ahmet(16)
- Tosunoğlu, Büşra(16)
- Uysal, Ibrahim(16)
- Kurt, Kemal(15)
- Ozturk, Samet(15)
- Reis, Hatice Catal(15)
- Aksakal, Vecihi(14)
Yayınlar
- MakaleYalnız künye2011Scopus SJRQ2Effect of plant growth-promoting rhizobacteria and manure on yield and quality characteristics of Italian ryegrass under semi arid conditions
Yolcu, Halil; Turan, Metin; Lithourgidis, Anastasios; Çakmakçi, Ramazan; Koç, Ali
Plant growth-promoting rhizobacteria (PGPR) appeared as a promising alternative for organic fertilization. A field experiment was carried out to evaluate the effects of PGPR and solid cattle manure application on yield, quality, and mineral concentrations of Italian ryegrass (Lolium multiflorum Lam.) under semi arid conditions in Turkey. The treatments included: three manure application rates (i.e. M1, 10; M2, 20; and M3, 30 Mg ha -1), five PGPR strains (i.e. RC11, Bacillus subtilis; RC21, Variovorax paradoxus; RC105, Paenibacillus polymyxa; RP24/3, Paenibacillus polymyxa; and RF29/2, Pseudomonas putida), and a control (without bacteria or manure application). Manure application did not increase yield of Italian ryegrass, whereas the treatments with RC21 and RP24/3 rhizobacteria provided the highest dry matter yield. All PGPR and manure applications increased crude protein concentration of Italian ryegrass. The M3 manure rate and most treatments with PGPR (except RC11) produced greater crude protein yield than that of control. In addition, concentrations of P, S, Mg, Cu, Zn, and Fe in most PGPR and manure applications were greater than those of control.
AtıfScopus18WoS12
İncele - BildiriYalnız künye2011Ambient and forced vibration tests of a box girder concrete bridge model
Altunisik, A.C.; Bayraktar, A.; Sevim, B.
In this paper, ambient and forced vibration tests of a box girder laboratory con-crete bridge model are described to obtain experimental dynamic characteristics such as natural frequencies, mode shapes and damping ratios. The bridge deck consists of a main span of 3m and two side span of 1.5m each. The total bridge length is 6m and width of bridge is 0.60m. Heights of the bridge column and bridge deck are 0.80m and 0.30m, respectively. In the forced vibration tests, excitation of the bridge model is induced by an impact hammer. The ambient vibration tests are conducted under natural excitation such as wind and small impact effects. The Enhanced Frequency Domain Decomposition method in the frequency domain and the Sto-chastic Subspace Identification method in the time domain are used to extract the dynamic characteristics. At the end of the study, dynamic characteristics obtained from ambient and force vibration tests are compared with each other. It is seen that there is a good agreement be-tween both results and they are nearly closed to each other.
- MakaleYalnız künye2011Scopus SJRQ2Total electricity and hydroelectric energy generation in Turkey: Projection and comparison
Akpinar, A.; Kömürcu, M.I.; Özölçer, I.H.; Şenol, A.
The main goal of this study is to forecast total electricity and hydroelectricity energy generation using historical electricity energy production data in order to determine the future level of electricity and hydroelectricity energy generation in Turkey. For this purpose, Turkey's electricity energy sector was reviewed during the period of 1940-2005. The total electricity and hydroelectricity energy generation were then modelled using historical energy generation data as years with regression analysis. Additionally, the portion that hydroelectric energy generation of Turkey has within total electricity energy production and probable meeting capacity of Turkey's hydroelectric potential of its future total demand was determined. According to the results, it is deduced that hydropower energy will have portion of 13.6% within the total electricity energy generation in 2030. In addition, it is concluded that the whole of Turkey's technical and economical hydroelectric energy potential that is equal 129.9 billion kWh will be used in the year of 2102 if the current trend continues.
AtıfScopus6WoS5OpenAlex7İncele - MakaleYalnız künye2011Scopus SJRQ1Investigation of water length effects on the modal behavior of a prototype arch dam using operational and analytical modal analyses
Sevim, Bariş; Bayraktar, Alemdar; Can Altunişik, Ahmet
This study determines the water length effects on the modal behavior of a prototype arch dam using Operational and Analytical Modal Analyses. Achievement of this purpose involves construction of a prototype arch dam-reservoir- foundation model under laboratory conditions. In the model, reservoir length was taken to be as much as three times the dam height. To determine the experimental dynamic characteristics of the arch dam using Operational Modal Analysis, ambient vibration tests were implemented for empty reservoir and three different reservoir water lengths. In the ambient vibration tests, the dam was vibrated by natural excitations provided from small impact effects and the response signals were measured using sensitive accelerometers. Operational Modal Analysis software process signals collected from the ambient vibration tests, and Enhanced Frequency Domain Decomposition and Stochastic Subspace Identification techniques estimated modal parameters of the dams. To validate the experimental results, 3D finite element model of the prototype arch dam was modeled by ANSYS software for empty reservoir and three different reservoir water lengths, and dynamic characteristics of each model were determined analytically. At the end of the study, experimentally and analytically identified dynamic characteristics compared to each other. Also, changes on the natural frequencies along to water length are plotted as graphs. Results suggest that reservoir water complicates the modal behavior of the arch dam significantly.
AtıfScopus26WoS22OpenAlex21İncele - BildiriYalnız künye2011Scopus SJRQ4A logic simplification based on expert system application for TBC diagnosis
Sümbül, Harun; Başçiftçi, Fatih; Lin, JC; Nikita, KS
Tuberculosis (TBC), caused by the bacterium My tuberculosis (Mtb), is a growing international health crisis [1]. TBC is one of the main causes of death produced by infectious illness and is responsible for almost 3 millions deaths every year [2]. In this study, a controlled Expert System (ES) have designed to diagnosis of TBC and truth table have created by considering the probabilities of TBC (12 symptom, 212=4096 different cases). According to the probabilities of TBC, 6 different cases have accepted as output values and reduced rule bases have obtained. These output values have been processed by an ES and have tried to diagnosis of TBC with help to ES. We obtained very good results and the results of analyses carried out indicated that controls performed with ES provide less time, less probability, reliable and consistent diagnosis and that are feasible in real life.
AtıfScopus1İncele - MakaleYalnız künye2011Scopus SJRQ3The effects of some organic and chemical fertilizer applications on yield, morphology, quality and mineral content of common vetch (Vicia sativa L.)
Yolcu, Halil
A field experiment was conducted to evaluate the effects of some organic and chemical fertilizers on morphological, yield and quality properties and mineral contents of common vetch (Vicia sativa L.) between 2007 and 2008 in Gümüşhane, Turkey. Treatments were control (no fertilizer), liquid manure (LM = 51-52 L ha -1N), chemical fertilizer (CF = 30 kg N ha -1+ 80-100 kg P 2O 5ha -1), three leonardite doses (L 1= 2.8; L 2= 5.6 and L 3= 8.4 kg N ha -1), three zeolite doses (Z 1= 0.4; Z 2= 0.8 and Z 3= 1.2 N kg ha -1) and three solid cattle manure doses (SM 1= 34-35 kg N ha -1, SM 2= 68-70 kg N ha -1, SM 3= 102-105 kg N ha -1). Dry hay yield (DHY), leaf weight, stem weight, plant height, leaf number, crude protein content (CP), crude protein yield (CPY), acid detergent fiber (ADF), neutral detergent fiber (NDF), Ca, Fe, K, Mg, B, Cu, Mn, Na, Ni, P, Pb, S and Zn contents were determined. Organic and chemical fertilizer applications had significant effect (P<0.01) on DHY, leaf weight, stem weight, CP, CPY and mineral contents except leaf number, ADF and NDF in the both years. The plant height were significantly (P<0.05) affected by the treatments in the first year. The SM 2application in the first year and control and LM applications in the second year resulted to obtain improved yield components and crude protein yield. Z 2and Z 3applications also loomed large in terms of mineral contents.
AtıfScopus12WoS13TR Dizin11
İncele - MakaleYalnız künye2011Scopus SJRQ3Aromatisation in adducts of a-terpinene: Influence of hindered internal Rotations
Kaya, Afşin Ahmet; Şengül, Mehmet Emin; Menzek, Abdullah; Kayaardi, Ibrahim; Karakuş, Murat; Şahin, Ertan
Each adduct of α-terpinene with p-quinone and 1,4-naphthoquinone in Ac2O/Et3N at 180 °C gives two aromatic products, one of which had a distinctive smell formed by the loss of an ethylene group. Here, we report the crystal structure of (1RS, 4RS)-1-isopropyl-4-methyl-1,4-dihydro- 1,4-ethanoanthracene-9,10-diyl diacetate. It is crystallised in an orthorhombic space group, Pbca, with cell dimensions a = 10.2899(7), b = 19.7804(9), c = 19.7519(8) Å and Z = 8. According to its NMR and X-ray diffraction data, the isopropyl and acetate groups slowly rotate.
AtıfScopus4WoS4OpenAlex2İncele - MakaleYalnız künye2011Scopus SJRQ1Restructuring of Turkey's electricity market and the share of hydropower energy: The case of the Eastern Black Sea Basin
Uzlu, Ergun; Akpinar, Adem; Kömürcü, Murat Ihsan
This paper presents the historical development of Turkey's electricity power sector, the efforts for introducing competition in the power industry in Turkey, and the concerns regarding restructuring in Turkey. The contribution of the hydropower energy potential in Turkey to the reconstruction of the electricity structure in Turkey is also investigated. Then, among the 25 hydrological basins in Turkey, the Eastern Black Sea Basin located in the northeast of Turkey, which has great advantages from the view point of small hydropower potential or hydropower potential without storage, is chosen as the case study to carry out some investigations concerning its potential and to analyze the contribution of the private sector (the corporate body) in regard to the development of hydro potential in this basin within the scope of the 4628 Electricity Market Law. With this law, concerning the restructuring of the electricity market, private sector investments in this segment have increased. In total, 1524 hydroelectric power projects with 22 360 MW installed capacity has been implemented until January 22nd, 2009 and this figure is continuously rising.
AtıfScopus31WoS27OpenAlex36İncele - BildiriYalnız künye2011Operational modal testing of an arch type steel highway bridge using SSI technique
Altunişik, A.C.; Bayraktar, A.; Sevim, B.
The paper determines the dynamic characteristics of an arch type steel highway bridge applying ambient vibration testing. A modern steel highway bridge which has arch type structural system with 216m total length and located in the Ayvacik county of Samsun, Turkey is selected as an application. Because of the fact that the bridge connects the villages which are separated with Suat Ugurlu Dam Lake, it has a major logistical importance for this region. The construction of the bridge completed in 2009 and opened the traffic. The experimental meas-urements are carried out by ambient vibration tests under traffic loads. Vibration data are gath-ered from the bridge deck. Measurement time, frequency span and effective mode number are determined considering similar studies in the literature and initial finite element analysis re-sults. Stochastic Subspace Identification technique (SSI) in the time domain are used for the output only modal identification and dynamic characteristics such as natural frequencies, mode shapes and damping ratios are determined, experimentally.
- MakaleYayıncıda açık erişim2011Scopus SJRQ3Analysis of support requirements for a tunnel portal in weak rock: A case study from Turkey
Kaya, Ayberk; Bulut, Fikri; Alemdaǧ, Selçuk; Sayin, Aytuna
In this paper, engineering geological properties of the entrance portal section of Konakönü Tunnel, located on Black Sea Coastal Highway, Turkey, is studied. Moderately weathered basaltic and andesitic tuffs orderly to be driven by the entrance portal section. Tunnel portal design in weak rock presents some special challenges to the designers, since misjudgements in the design of tunnel can lead to very costly failures. The entrance portal was analyzed by empirical and numerical methods. Both field and laboratory studies were carried out during this study. Field studies involved geological mapping, detailed discontinuity surveying and sampling. Laboratory tests were carried out to determine the physico-mechanical and elastical properties of rock units. For this purpose, tunnel stability analyses were performed at the entrance portal section. The RMR (rock mass rating), Q (rock mass quality), RMi (rock mass index), NATM (new Austrian tunnelling method) and GSI (geological strength index) systems were employed for empirical rock mass quality determination and preliminary tunnel portal support design. The parameters calculated by the empirical methods were used as input parameters for the FEM (finite element method) analysis. The results from the two methods were compared and preliminary support designs were carried out. This comparison suggests that for more reliable support design, empirical and finite element methods should be combined.
AtıfScopus32OpenAlex33İncele - MakaleYalnız künye2011Scopus SJRQ2The effect of fin pitch on heat transfer and fluid flow characteristics in the entrance region of a finned concentric passage
Kuvvet, Kemal; Yavuz, Tahir
In this study, the heat transfer and fluid flow characteristics in the unfinned and internally finned concentric passage (smooth and finned annulus) are investigated experimentally. The turbulence characteristics, mean flow, pressure drop and heat-transfer parameters in the entrance region of a concentric passage of diameter ratio 0.2 are measured. The hot-wire anemometer and the liquid-crystal technique are used for the turbulence and mean flow and the heat transfer measurements, respectively. The finned passage is designed as the fin width (W) of 2 mm, the fin height (H) of 2, 4, 6 and 8 mm and the fin pitch (P) of 20, 30 and 40 mm. Reynolds number ranges from 1.8 .104 to 1.24.105 and from 1.65.104 to 7.65.104 for flow and pressure drop and heat transfer measurements, respectively. Experiments are performed for the smooth and finned concentric passages by varying flow and fin parameters and the effects of the fin pitch are investigated. The developing of fluid flow is analyzed and the variation of turbulence intensity, friction factors, local and mean convective heat transfer coefficients in the smooth and finned concentric passages are obtained. Results obtained in the finned concentric passages are compared with the results of the smooth passage. For the average Nusselt numbers and friction factor, empirical equations are developed. As a result, it is seen that the friction factor in the finned passage increases between 3.61 and 18.05 times while the average Nusselt number augments between 1.36 and 5.23 times on the inner surface and between 1.03 and 1.80 times on the outer surface.
AtıfScopus4WoS4TR Dizin1İncele - MakaleYalnız künye2011Scopus SJRQ1Determination of seasonal changes in olive oil by using differential scanning calorimetry heating thermograms
Ilyasoglu, Huri; Ozcelik, Beraat
Thermal properties (upon heating) of extra virgin olive oils (EVOOs) from Aegean cultivars were determined to evaluate the possibility of using differential scanning calorimetry (DSC) as a tool for monitoring seasonal changes in chemical composition. Chemical properties of the samples were analyzed to assess the relationship between the thermal properties and chemical properties as well. The thermal properties of Aegean cultivars were found to be influenced by major components (palmitic acid, oleic acid, linoleic acid, triolein and palmitodiolein). The melting offset temperature, the temperature range of melting and the melting enthalpy of Aegean cultivars presented significant differences with respect to crop season (p < 0.05). DSC may be utilized to evaluate compositional changes with respect to crop season.
AtıfScopus8WoS7OpenAlex7İncele - MakaleYalnız künye2011Scopus SJRQ1Petrochemistry and U-Pb zircon ages of adakitic intrusions from the pulur massif (eastern pontides, ne Turkey): Implications for slab rollback and ridge subduction associated with Cenozoic convergent tectonics in the eastern Mediterranean
Eyuboglu, Yener; Santosh, M.; Chung, Sun-Lin
The well-preserved magmatic arc in the eastern Pontides orogenic belt of northeastern Turkey offers critical clues on convergent margin tectonics associated with the late Mesozoic-early Cenozoic geodynamic evolution of the eastern Mediterranean region. Here we investigate the petrology, geochemistry, and U-Pb zircon chronology of adakitic intrusions from the Pulur region in the southern zone of the eastern Pontides belt. The intermediate to felsic intrusives in the Pulur region are characterized by the presence of abundant plagioclase, amphibole, and biotite phenocrysts. The rocks display extreme light rare earth element enrichment (LaN YbN p13.69-51.08); high Al2O3 (15.46-17.47 N Nwt%), Na2O (3.57-8.43 wt%), Sr (324.8-1468 ppm), and La (13.9-55.8 ppm) concentrations; a high Sr/Y ratio (35-473); and low Y (3-12.6 ppm) and heavy rare earth element concentrations, closely comparing with the typical features of adakites. Zircons extracted from the Pulur adakites show euhedral crystal shapes, oscillatory zoning patterns, andhigh Th/U ratios (up to 3.33) consistent with their magmatic origin. Their 206Pb/238U ages show a range of 55.21-53.07 Ma, correlating the magmatism to the early Eocene. We propose a tectonic model involving the initiation of a slab rollback and simultaneous opening of a slab window during ridge subduction in a south-dipping sub duction zone for the origin of the Tertiary adakitic and nonadakitic magmatism in the eastern Pontides orogenic belt. We also identify a close relation between slab rollback processes and back arc extension, which led to the opening of the Tertiary basins in the southern part of the eastern Pontide orogenic belt. The eastern Pontide orogenic belt is one of the world's largest metallogenic provinces, and it hosts various economic mine ralizations such as volcanogenic massive sulfide, epithermal gold-silver, porphyry copper-molybdenum, skarn-type, and chromite. However, the adakitic intrusions exposed in the southern part of the eastern Pontide orogenic belt are devoid of ore deposits, which leads us to propose that the Lutetian or later nonadakitic granitic intrusions exposed at the north of the Gumushane-Bayburt-Ispir line were probably responsible for the epithermal gold mineralization in this belt.
AtıfScopus51WoS49OpenAlex51İncele - MakaleYalnız künye2011Scopus SJRQ2Mild and severe anal incontinence after lateral internal sphincterotomy: Risk factors, postoperative anatomical findings and quality of life
Kement, M.; Karabulut, M.; Gezen, F.C.; Demirbas, S.; Vural, S.; Oncel, M.
Aim: This study aims to evaluate the risk factors for incontinence after lateral internal sphincterotomy (LIS) and assess quality of life in different levels of incontinence. Methods: All consecutive patients (n = 253) with chronic anal fissure who underwent LIS between 2003 and 2006 were retrospectively reviewed. All patients were questioned for possible anal incontinence according to the Wexner Incontinence Score (WIS). Demographics, vaginal delivery history, additional procedures and surgeon's experience were evaluated as risk factors. Endoanal ultrasound (EUS) was performed in incontinent patients to assess the thickness of the remaining internal sphincter and to evaluate any injury in the external sphincter. Quality of life was questioned with SF-36. Results: Twenty-eight (11.7%) patients suffered from incontinence (mean WIS = 3.6 ± 2.5). The search for a risk factor was unsuccessful when continent and incontinent groups were compared. In subgroup analyses, patients were found to be suffering from mild (WIS <5, n = 19) or severe (WIS >5, n = 9) incontinence. Vaginal delivery history was found more often in the severely incontinent subgroup than in the continent group (p < 0.05). Also, vaginal delivery history and the additional procedures were more frequently observed in the severely incontinent subgroup than in the mildly incontinent subgroup. EUS did not find any external sphincter injury in these cases. WIS had negative correlations with the physical and mental component scores of SF-36. Conclusion: In our opinion, the threat for incontinence is unpredictable; however, vaginal delivery history may increase the risk of severe incontinence.
AtıfScopus14WoS13OpenAlex17
İncele - MakaleYalnız künye2011Scopus SJRQ2Finite element model calibration of berke arch dam using operational modal testing
Sevim, Bariş; Bayraktar, Alemdar; Altunişik, Ahmet Can
This paper presents the finite element calibration of Berke Arch Dam by using Operational Modal Testing. Achievement of this purpose involves structural vibration characteristics of Berke Arch Dam using analytical and Operational Modal Analyses. Therefore, the study has two parts-analytical and experimental. In the analytical part of the study, the authors developed a 3D finite element model of Berke Arch Dam-reservoir-foundation system using ANSYS software, and analytically determined vibration characteristics such as natural frequencies and mode shapes. In the experimental part of the study, sensitive accelerometers were placed to several points of Berke Arch Dam, and ambient vibration tests were conducted over four days to obtain dynamic characteristics. The Enhanced Frequency Domain Decomposition technique is used to estimate natural frequencies, mode shapes and damping ratios of the Berke Arch Dam experimentally. Results showed that there were some differences between analytical and experimental natural frequencies of the dam. Therefore, an analytical model of Berke Arch Dam was calibrated to minimize these differences by changing material properties. Analytical results obtained from the calibrated model mainly conform to those of the experimental model.
AtıfScopus53WoS43OpenAlex44İncele - MakaleYalnız künye2011Scopus SJRQ2Solid waste management practices in Turkey
Berkun, Mehmet; Aras, Egemen; Anılan, Tugce
As an economically developing country, Turkey has very well operated integrated solid waste management applications structured on modern facilities, besides over 2,000 scattered open dump areas in the country. Integrated waste management applications seem eligible for the metropolitan cities like Istanbul and Izmit (Kocaeli). Attempts have not been encouraging for the scattered regional settlements using central storage sites due to financial shortages and received rejections from nearby settlements. Small-scale compact solid waste management systems with materials recycling and composting can be more suitable alternatives in the small-scale regional settlements. The major constituents of municipal solid waste are organic in nature and approximately a quarter of municipal solid waste is recyclable. Although paper, including cardboard, is the main constituent, the composition of recyclable waste varies strongly by the source or the type of collection point. Solid wastes need primary treatment in order to be suitable for incineration and composting. Turkey needs to give more emphasis on the usage of modern solid waste removal technologies to overcome the overgrowing solid waste disposal problems.
AtıfScopus25WoS18OpenAlex33İncele - BildiriYalnız künye2011Scopus SJRQ1Hydroxyapatite production on ultrafine-grained pure titanium by micro-arc oxidation and hydrothermal treatment
Alsaran, A.; Purcek, G.; Hacisalihoglu, I.; Vangolu, Y.; Bayrak, O.; Karaman, I.; Celik, A.
In this study, pure-Ti (Grade-2) was severely plastically deformed by equal-channel angular extrusion (ECAE) to improve its strength, and then subjected to micro arc oxidation (MAO) and hydrothermal treatment (HT) to achieve improved surface behavior with hydroxyapatite (HA)-containing titania (TiO(2)) coating. Microstructure, tensile properties and wear behavior of UFG Ti were investigated systematically before and after surface modification. ECAE considerably enhanced the strength of coarse-grained (CG) Ti by forming an ultra-fine grained (UFG) microstructure with high dislocation density. The application of MAO with or without HT did not cause remarkable decrease in strength and ductility of CG and UFG Ti, but resulted in a considerable increase in its wear resistance and osseointegration due to the formation of hard and adhered HA-containing TiO2 coating on the surface. It can be concluded that the use of ECAE plus MAO/HA coating provides a simple and effective procedure to obtain pure Ti with high strength and high wear resistance. The improved bulk and surface properties can make this biocompatible material a good potential candidate for biomedical applications instead of alloys including toxic elements. (C) 2011 Elsevier B.V. All rights reserved.
AtıfScopus61WoS61OpenAlex65İncele - MakaleYalnız künye2011Scopus SJRQ1Adakite-like granitoid porphyries in the Eastern Pontides, NE Turkey: Potential parental melts and geodynamic implications
Karsli, Orhan; Ketenci, Murat; Uysal, Ibrahim; Dokuz, Abdurrahman; Aydin, Faruk; Chen, Bin; Kandemir, Raif; Wijbrans, Jan
The tectonic setting of the Eastern Pontides during the late Mesozoic to early Cenozoic remains a subject of debate. Petrogenesis of adakite-like granitoid porphyries plays a critical role in determining the nature of the lower continental crust and mantle dynamics during orogenic processes in the region. Here we describe, for the first time, the late Paleocene to early Eocene adakite-like granitoid porphyries from the northern part of the Eastern Pontides although their counterparts in the southern part have recently been found. The adakitic porphyries, which emplaced into the subduction-related Turonian-Santonian volcanics from northern part of the region, consist of I-type calc-alkaline quartz monzonite-tonalite (SiO2 = 62.89-65.07 wt.%) and high-k calc-alkaline granodiorite-granite associations (SiO2 = 69.06-70.43 wt.%). The former displays peraluminous to metaluminous signatures, whereas the latter shows peraluminous geochemical character. The granite-granodiorite porphyries have high K2O (3.32-3.84 wt.%), and low Na2O (3.48-4.61 wt.%) and MgO (0.91-1.04 wt.%) relative to the quartz monzonite-tonalite association (K2O = 1.50-1.92 wt.%; Na2O = 4.08-6.45 wt.%; MgO = 1.44-2.07 wt.%). Ar-Ar geochronology studies on the amphibole separates reveal that the adakite-like porphyries have a crystallization ages of 51.34 +/- 0.27 to 53.55 +/- 0.34 Ma. Here, we contend that these rocks were formed by partial fusion of a mafic lower continental crust in a collisional phase but not in a subduction setting. All the samples exhibit the typical geochemical characteristics of adakite, that is, high Sr (250-1141 ppm), high Sr/Y ratios (16-147), low Y (6.8-14.8 ppm) and low HREE concentrations; they are similar to adakites formed by slab melting associated with the subduction zone. However, the rocks exhibit heterogeneity in isotopic composition, with I-Sr ranging from 0.70554 to 0.70986, epsilon(Nd) (51 Ma) from -8.5 to -0.9 and Nd model ages from 0.72 to 1.26 Ga. The samples are characterized by relatively high Th, Th/U and no significant Eu anomalies, implying that garnet was stable in their source during partial melting. The compositional diversity between rock groups is probably related to partial melting of heterogeneous lower crustal source. All of the features are inconsistent with a slab-melting origin and slab-related petrogenetic model, but instead, they favor an origin by melting of heterogeneous lower continental crust due to a thermal anomaly that was induced by the upwelling of the asthenosphere through a slab break-off in a collisional setting. These interpretations argue against the evidence for the presence of an early Cenozoic arc setting in the Eastern Pontides. Instead, the early Cenozoic time in the region may be attributed to a geodynamic response to a post-collisional uplift phase that occurred along the continent-continent collision between the Pontide and the Anatolide-Tauride blocks. (C) 2011 Elsevier B.V. All rights reserved.
AtıfWoS123OpenAlex120İncele - MakaleYalnız künye2011Scopus SJRQ1Migrating magmatism in a continental arc: Geodynamics of the Eastern Mediterranean revisited
Eyuboglu, Yener; Santosh, M.; Dudas, Francis O.; Chung, Sun-Lin; Akaryali, Enver
The eastern Pontide orogenic belt in Turkey offers a critical region to evaluate the geodynamic evolution of the eastern Mediterranean region during the late Mesozoic-Cenozoic. Here we synthesize results from our exhaustive database on the geochemical characteristics of adakitic magmatism from 137 bodies covering 7 domains in the southern zone of eastern Pontides. Together with new Pb-Sr-Nd results, we show that the adakitic magmatism in the eastern Pontide belt is clearly linked to slab window processes during ridge subduction, as against the earlier models that assumed partial melting of a delaminated or thickened lower continental crust following collision. The isotopic compositions display a complex pattern and suggest mixing of multiple source materials such as depleted mantle, enriched lithospheric mantle, and upper crust. We also confirm a southward polarity of subduction as against the previous models that assumed a northward subduction. We supplement our model with evidence for a northward propagation of the adakitic magmatism, spatial and temporal variations in arc magmatism, presence of south-dipping reverse faults and a synthesis of the available paleomagnetic data. Our studies also suggest that the Black-Sea is a remnant of the Tethyan ocean that was situated to the north of the arc during the late Mesozoic-Cenozoic as against the correlation to a late Mesozoic-Cenozoic back-arc basin related to a northward subduction of the Paleo- or Neo-tethyan oceanic lithosphere in alternate models. (C) 2010 Elsevier Ltd. All rights reserved.
AtıfScopus58WoS52OpenAlex56İncele - MakaleYalnız künye2010Scopus SJRQ3Gündüz şartlarında üçgen kesitli çatıda doğal taşınım
Küçük, Haydar; Gedikli, Hasan
The natural convection is numerically investigated in a roof of triangular cross section under constant heat flux with seven different values depending on daylight on the inclined wall, constant wall temperature on the bottom wall and adiabatic on the vertical wall boundary conditions. Continuity, momentum and energy equations are solved by using finite volume method for laminar, two-dimensional and steady-state regime. Streamlines, isotherms, local and mean Nusselt numbers are presented for AR=0.25, 0.5, 0.75 and 1.0 and Ra=10³, 10⁴, 10⁵, 10⁶. The amount of heat flux ranges from 163 W/m² to 808 W/m² depending on daylight and the Prandtl number is chosen as 0.7. It is found out that the aspect ratio and Rayleigh number highly affect the heat transfer on the bottom and inclined walls while heat flux slightly affects.