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Koleksiyondaki öğeler
- MakaleAçık Erişim2011Scopus SJRQ2Stability properties of certain durum wheat genotypes for major quality characteristics; [Makarnalik buĝday genotiplerinin temel kalite kriterleri bakimindan stabilite özellikleri]
Sakin, Mehmet Ali; Düzdemir, Oral; Sayaslan, Abdulvahit; Yüksel, Ferhat
Many ecological regions of Turkey are suitable for the production of durum wheat, and therefore the yield and quality of this wheat should be improved. In this study, stability properties associated with the pasta quality of 25 durum wheat (Triticum durum Desf.) genotypes grown in 3 dif erent locations (Tokat-Kazova, Diyarbaki{dotless}r, and Sivas-Ulaş) for 2 years (2005-2006, 2006-2007) were investigated. Durum wheat genotypes were composed of 12 registered varieties and 13 advanced experimental lines. Field trials were conducted in a randomized complete block design with 3 replications. Protein content, gluten index, sedimentation and specif c sedimentation volumes, yellow pigment content, and lipoxygenase activity of the durum wheats were measured as major quality characteristics. T e regression coef cient (bi) and mean square of deviation from regression (S2 d) were employed as the stability parameters. Genotypes, growing environments, and their interactions were found to be statistically signif cant (P < 0.01) for all investigated quality characteristics. No cultivars were determined to be simultaneously stable for all of the quality characteristics, yet some of the genotypes prevailed for certain quality characteristics. T e genotypes with the same origin took part in the same group as judged by the cluster analysis. Of the advanced experimental durum wheat lines, Line - 1, Line - 7, Line - 20, and Gdem - 12, which displayed better quality characteristics than the overall means, can be used as breeding materials. Of the registered varieties, Aydin - 93, Çeşit - 1252, and Gidara were determined to be stable by both parameters in certain quality characteristics.
AtıfScopus9WoS8
İncele - MakaleYalnız künye2012Scopus SJRQ1Fast practical analytical model for analysis of backfill-rectangular tank-fluid interaction systems
Cakir, Tufan; Livaoglu, Ramazan
The paper describes a simple, efficient and reasonably accurate analytical model for analysis of backfill-rectangular tank-fluid interaction systems. The presented model uses Housner's two-mass approximation for fluid interaction and mass-spring-dashpot system for backfill interaction and accommodates a variety of features that may affect the behavior of rectangular tanks including fluid volume, backfill geometry, soil properties and flexible/rigid wall types. Unlike the conventional finite element and the finite difference models that require considerable effort and knowledge to prepare the input data, the proposed model requires only a few pieces of data to define the problem and control the analysis. A series of finite element simulations were also fulfilled on two real rectangular tanks subjected to backfill and fluid effects. A reasonably good accord was obtained comparing the analytical predictions to results from numerical simulations. Thus, it can be stated that the model may be used effectively to perform a broad suite of parametric studies at the design stage and also as a reliable tool for estimating the system behavior. The results obtained from parametric seismic analyses indicated that backfill interaction, wall flexibility and fluid interaction considerably affect the lateral displacements. The sloshing response, however, was not practically affected by the backfill interaction and the wall flexibility.
AtıfScopus24WoS23OpenAlex21İncele - MakaleYalnız künye2012Scopus SJRQ3Spatial variations of precursory seismic quiescence observed in recent years in the eastern part of Turkey
Öztürk, Serkan; Bayrak, Yusuf
A statistical analysis is made for the eastern part of Turkey in the beginning of 2009 by studying the phenomenon of seismic quiescence as a potential precursor of the main shocks. The results produced four areas having seismic quiescence in the beginning of 2009. These areas are observed to be centered at 39.96°N-40.69°E (around Aşkale, Erzurum), 39.36°N-39.74°E (around Ovaci{dotless}k, Tunceli), 39.02°N-40.52°E (including Elazi{dotless}ǧ and Bingöl), and 38.45°N-42.94°E (Van Lake). Based on the recent results showing 5 ± 1.5 years quiescence before the occurrence of an earthquake in this region, the future earthquake would be expected between 2009. 5 and 2010. 5. The future earthquake occurrence may reach 2012 if we consider the standard deviation of average seismic quiescence as ±1.5 years. We have found that the MW = 6.0 Elazi{dotless}ǧ earthquake on 8 March 2010, followed a seismic quiescence starting about 5 years before the main shock. Thus, special interest should be given to the other regions where the seismic quiescence is observed.
AtıfScopus27WoS22OpenAlex30İncele - MakaleYalnız künye2014Scopus SJRQ1Assessment of strength properties of cemented paste backfill by ultrasonic pulse velocity test
Yilmaz, Tekin; Ercikdi, Bayram; Karaman, Kadir; Külekçi, Gökhan
Ultrasonic pulse velocity (UPV) test is one of the most popular non-destructive techniques used in the assessment of the mechanical properties of concrete or rock materials. In this study, the effects of binder type/dosage, water to cement ratio (w/c) and fines content (<20 μm) of the tailings on ultrasonic pulse velocity (UPV) of cemented paste backfill (CPB) samples were investigated and correlated with the corresponding unconfined compressive strength (UCS) data. A total of 96 CPB samples prepared at different mixture properties were subjected to the UPV and UCS tests at 7, 14, 28 and 56-days of curing periods. UPV and UCS of CPB samples of ordinary Portland cement (CEM I 42.5 R) and sulphate resistant cement (SRC 32.5) initially increased rapidly, but, slowed down after 14 days. However, UPV and UCS of CPB samples of the blast furnace slag cement (CEM III/A 42.5 N) steadily increased between 7 and 56 days. Increasing binder dosage or reducing w/c ratio and fines content (<20 μm) increased the UCS and UPV of CPB samples. UPV was found to be particularly sensitive to fines content. UCS data were correlated with the corresponding UPV data. A linear relation appeared to exist between the UCS and UPV of CPB samples. These findings have demonstrated that the UPV test can be reliably used for the estimation of the strength of CPB samples.
AtıfScopus145WoS133OpenAlex136
İncele - BildiriAçık Erişim2014Scopus SJRQ3Performance analysis of linear permanent magnets synchronous motor by scalar control method (v/f)
Otkun, ÖZcan; Doğan, R. ÖZgüR; Akpinar, A. Sefa
This study is conducted to improve the performance of Linear Permanent Magnet Synchronous Motor by using Scalar Control Method. To do this, open and closed loop control methods are used. The study is modeled with MATLAB/SIMULINK. Firstly, the Simulink model has been developed by using equations dq axis system of the motor. Then, a scalar control method is modeled. Thirdly, open and closed loop control forms are modeled. From these models, current, thrust force, and speed graphs were obtained. It is seen on the graphs, the motor’s closed loop PID control at scalar control method provide positive results.
- MakaleAçık Erişim2015Scopus SJRQ3Comparison of perioperative oxidative stress in endovascular and open repair of abdominal aortic aneurysm
Doğan, Orhan Veli; Menteşe, Ümit; Doğan, Süheyla; Usta, Sefer; Turan, İbrahim; Haliloğlu, Ergün; Karahan, Süleyman Caner
Background/aim: To investigate the differences in perioperative oxidative stress (OS) in abdominal aortic aneurysm (AAA) patients treated with either endovascular repair (EVAR) or open repair (OR).; Materials and methods: Twenty patients (11 OR, 9 EVAR) treated for AAA with no known malignant or inflammatory disease and an aneurysm diameter of over 5 cm and no rupture were included in the study. Blood samples were obtained preoperatively, during aortic occlusion, and 1 h and 24 h after reperfusion. Total antioxidant status (TAS), total oxidative stress (TOS), and malondialdehyde (MDA) levels were measured and oxidative stress index (OSI) was calculated.; Results: OSI at 1 h and 24 h after reperfusion was higher in the EVAR group (P = 0.004 and P = 0.002, respectively). TAS levels were higher (P = 0.001, P = 0,029). MDA levels showed no difference (P = 0.291, P = 0.076). TOS levels were lower 24 h after reperfusion in the EVAR group (P = 0.018). Conclusion: Markers of oxidative stress were lower in the EVAR group. This may be associated with advantages of EVAR. More studies are required for a clear-cut conclusion.
AtıfScopus2WoS2OpenAlex1
İncele - MakaleYalnız künye2011Scopus SJRQ2Effects of random material and geometrical properties on structural safety of steel-concrete composite systems
Çavdar, Özlem; Bayraktar, Alemdar; Çavdar, Ahmet
A stochastic finite element-based algorithm for probabilistic analysis of structural systems made of composite sections with random material and geometrical properties under earthquake forces is proposed in this paper. Uncertainties in the structural parameters can be taken into account in this algorithm. For the perturbation-based stochastic finite element method, only the first two moments of random variables need to be known, and is numerically much more efficient and feasible than simulation techniques. The efficiency and accuracy of the proposed algorithm are validated by comparison with results of Monte Carlo simulation method. A summary of stiffness matrix formulation and perturbation-based stochastic finite element dynamic analysis formulation of structural systems made of composite sections is given. These are followed by suitable numerical examples, which indicate that employment of such a dynamic stochastic finite element method leads to significant economical, efficient and accurate solutions for the dynamic analysis of composite structures with stochastic parameters under earthquake forces.
AtıfScopus3WoS3OpenAlex3İncele - MakaleYalnız künye2015Scopus SJRQ1Geochemistry, Re-Os isotopes and highly siderophile element abundances in the Eastern Pontide peridotites (NE Turkey): Multiple episodes of melt extraction-depletion, melt-rock interaction and fertilization of the Rheic Ocean mantle
Dokuz, Abdurrahman; Uysal, Ibrahim; Dilek, Yildirim; Karsli, Orhan; Meisel, Thomas; Kandemir, Raif
We report on the structure, geochemistry, Re-Os isotopes and relative abundances of highly siderophile elements (HSEs) of the Paleozoic peridotite-basalt occurrences in the Eastern Pontide belt of northeastern Turkey. These peridotites and the associated basaltic rocks are the remnants of the Rheic oceanic lithosphere, incorporated into the Eurasian continental margin during the Variscan (Hercynian) orogeny. The peridotites display a complex record of multiple magmatic, metasomatic and metamorphic events in different tectonic settings during the evolution of the Rheic upper mantle. The Beyçam harzburgite (BH) contains low Al2O3 (0.51-1.88 anhydrous wt.%) and high MgO (41.35-42.34 wt.%) contents, and its bulk-rock trace element compositions are less than 10% of the primitive upper mantle (PUM) values. The platinum, Pd and Re contents of the Beyçam harzburgite are highly depleted, whereas its Os, Ir, and Ru contents are slightly enriched relative to the PUM values. Its Pd and Re contents that are higher than those of the fertile Pulur lherzolite (PL) to the south and the absence of an isochronous relationship between its 187Os/188Os and 187Re/188Os show that the trace element distribution and the isotope ratios of the Beyçam harzburgite were significantly modified after the first melt-extraction episode. The first melt extraction occurred beneath the Rheic mid-ocean ridge spreading center, whereas the second melt extraction occurred in a mantle wedge above a Rheic subduction zone. The primary magmatic phases of the Pulur lherzolite show the geochemical characteristics typical for fertile lherzolite, formed in the early stages of oceanic lithosphere generation subsequent to the continental break up. The Pulur lherzolite also contains a secondary magmatic phase in the form of networks of clinopyroxene veins and channels, which are interpreted as an evidence for solid state melt-rock reactions between the lherzolite and a percolating basaltic melt above a subduction zone. This clinopyroxene addition resulted in the formation of variable concentrations of Al2O3 (2.47-4.33wt.%) and MgO (29.76-40.10wt.%) in the lherzolite. The rhenium, Pd and Pt concentrations of the Pulur lherzolite are depleted relative to the PUM values, whereas the Os, Ir and Ru concentrations are in the range of the PUM values as commonly observed in peridotites with a melt depletion history. The high suprachondritic 187Os/188Os is, however, inconsistent with a simple melt depletion history, and can be explained by the addition of radiogenic Os-bearing sulfide phases into the lherzolite as a result of melt-rock reactions. Basaltic rocks with an island arc tholeiitic composition from the Beyçam area represent the partial melting product of the moderately depleted Beyçam harzburgite and the basaltic parental melt from which the clinopyroxene precipitated. The covariation between the 187Re/188Os and 187Os/188Os of these basaltic rocks defines an isochron age of 377±8Ma (late Devonian). The combined structural, geochemical and isotope data indicate a prolonged history of multiple episodes of melt extraction-depletion, and melt-rock interaction and fertilization of the mantle lithosphere of the Rheic Ocean.
AtıfScopus35WoS31OpenAlex31İncele - MakaleYalnız künye2014Scopus SJRQ3Backfill and subsoil interaction effects on seismic behavior of a cantilever wall
Cakir, Tufan
The main focus of the current study is to evaluate the dynamic behavior of a cantilever retaining wall considering backfill and soil/foundation interaction effects. For this purpose, a three-dimensional finite element model (FEM) with viscous boundary is developed to investigate the seismic response of the cantilever wall. To demonstrate the validity of the FEM, analytical examinations are carried out by using modal analysis technique. The model verification is accomplished by comparing its predictions to results from analytical method with satisfactory agreement. The method is then employed to further investigate parametrically the effects of not only backfill but also soil/foundation interactions. By means of changing the soil properties, some comparisons are made on lateral displacements and stress responses. It is concluded that the lateral displacements and stresses in the wall are remarkably affected by backfill and subsoil interactions, and the dynamic behavior of the cantilever retaining wall is highly sensitive to mechanical properties of the soil material.
AtıfScopus21WoS18OpenAlex19İncele - MakaleYalnız künye2015Scopus SJRQ3Mushroom management theory; Sample of health sector
Kiliç, Taşkin
Keeping in the dark by senior management from their subordinates is referred as "Mushroom Management". Within the scope of the present study, Mushroom Management application and exposure levels of administers and employers in the health industry were tried to be determined. The theoretical part of the study has been developed based on reviews of literature and in conjunction with conducted researches. Field research has been completed by using interview method, applied to 30 senior level health managers and 30 health workers from Gümüşhane city in Turkey. According to the obtained results, 84% of managers apply mushroom management style, and 87% of employees perceive mushroom management behaviors.
AtıfScopus6İncele - MakaleAçık Erişim2011Scopus SJRQ1Solving a fractional order model of HIV infection of CD4+ T cells
Gokdogan, Ahmet; Yildirim, Ahmet; Merdan, Mehmet
In this paper, a multi-step differential transform method (MsDTM) is performed to give approximate and analytical solutions of nonlinear fractional order ordinary differential equation systems such as a model for HIV infection of CD4+ T cells. The numerical solutions obtained from the proposed method indicate that the approach is easy to implement and accurate when applied to systems of fractional differential equations. Some figures are presented to show the reliability and simplicity of the methods.
AtıfScopus79WoS59OpenAlex71İncele - MakaleAçık Erişim2015Scopus SJRQ2A new species of Zachaeus C.L. Koch from Turkey (Opiliones, Phalangiidae)
Kurt, Kemal; Koç, Halil; Yağmur, Ersen Aydın
A new species of harvestmen, Zachaeus seyyari sp. n. (Opiliones, Phalangiidae), is described and illustrated on the basis of both sexes from Şırnak Province in Turkey. Differences between the new species and related species are indicated. Photographs of its characteristic structures are also provided.
AtıfScopus1OpenAlex2İncele - BildiriYalnız künye2014Spatial and temporal analysis of current seismic quiescence in the east anatolian fault zone, Eastern Part of Turkey
Öztürk, S.; Sariçiçek, I.
In the scope of this study, an evaluation of recent seismic quiescence in the East Anatolian Fault Zone, eastern part of Turkey, is made by using the standard deviate Z-value. For this purpose, a statistical assessment of the spatial and temporal variations of the seismicity rate changes in the beginning of 2013is performed by using ZMAP software package. Results show that four areas with an apparently seismic quiescence may be important in the East Anatolian Fault Zone in the beginning of 2013. These anomalies are observed centered at 39.48°N-39.712°E (between Ovacik and Pülümür, Tunceli), the second one is found centered at 39.06°N-40.297°E (including Karakoçan, Sancak-Uzunpinar and Göynük fault zones), the third one is found centered at 38.55°N-38.763°E (between Malatya fault and EAFZ, north of Pötürge, Malatya) and the last one is found centered as 39.95°N-35.647°E (between Ceyhan-Yumurtalik-Karatas, Adana). The beginnings of these seismic quiescence anomalies are recently observed and nearly started in the beginning of 2007.For this reason, special attention should be given to these regions where the seismic quiescence is observed.
- MakaleYalnız künye2015Scopus SJRQ4Distortion bounds for a new subclass of analytic functions and their partial sums
Aktaş, Ibrahim; Orhan, Halit
In the present paper, we introduce a new subclass of functions which are analytic in the open unit disk. Also, we obtain coefficient inequalities for functions belonging to this class. Futhermore, we give some results associated with distortions bounds. In addition to that, we investigate lower bounds for partial sums of functions belonging to this class.
AtıfScopus4İncele - MakaleYalnız künye2015Scopus SJRQ3Numerical solution to inverse elliptic problem with neumann type overdetermination and mixed boundary conditions
Ashyralyyev, Charyyar; Akkan, Yasar
This article studies the numerical solution of inverse problems for the multidimensional elliptic equation with Dirichlet-Neumann boundary conditions and Neumann type overdetermination. We present first and second order accuracy difference schemes. The stability and almost coercive stability inequalities for the solution are obtained. Numerical examples with explanation on the implementation illustrate the theoretical results.
AtıfScopus22WoS19İncele - MakaleYalnız künye2012Scopus SJRQ1The total electricity energy production of the world, European Union, and Turkey: Projections and comparison
Akpinar, A.; Tavşan, F.; Kömürcü, Murat Ihsan; Filiz, M.H.; Kaygusuz, K.
This study aims to forecast the world's, European Union's (EU), and Turkey's electricity energy generation until 2030. For this purpose, the electricity energy sector of the world, EU, and Turkey was overviewed from past to present. The total electricity energy generation for the world, EU, and Turkey were then modelled by using historical energy generation data as years with regression analysis. Data from 1970 to 2004 for Turkey and data from 1980 to 2004 for the world and EU were used for the projections. Electricity energy productions have been forecasted up to year 2030. According to the results, it is determined that cubic (R2 = 0.997) and linear (R2 = 0.993) models for projection of the world's and EU's electricity energy generation, respectively, is fitness while the quadratic (R2 = 0.996) model fits for the projection of Turkey's total electricity energy generation and Turkey will have 0.995% of the world's electricity energy generation in 2030, while the EU will have 8.41% within the world's electricity energy generation in 2030 if the current trend continues.
AtıfScopus5WoS5OpenAlex8İncele - MakaleYalnız künye2013Scopus SJRQ1Effects of laminate carbon/epoxy composite patches on the strength of double-strap adhesive joints: Experimental and numerical analysis
Akpinar, Salih
In this study, mechanical properties of double-strap joints with aluminum or composite patches of different orientation angles at their overlap area were investigated under tensile loading. For this purpose, AA2024-T3 aluminum was used as adherend, while patches were either AA2024-T3 aluminum or 16-ply laminate of carbon/epoxy composite with five different orientation angles ([0]16, [90]16, [0/90]8, [45/-45]8, [0/45/-45/90]4). A two-part paste adhesive (DP 460) was used to bond adherend and patches. Six different types of joint samples were subjected to tensile loading. The effect of patch material on failure load and stress distribution was examined experimentally and numerically. As a result, it was concluded that the data obtained from 3-D finite element analysis were coherent with experimental results and additional to that fiber orientation angles of the patches markedly affected the failure load of joints, failure mode and stress distributions appeared in adhesive and composite.
AtıfScopus53WoS47OpenAlex52İncele - MakaleYalnız künye2012Scopus SJRQ1A-type granitoids from the Eastern Pontides, NE Turkey: Records for generation of hybrid A-type rocks in a subduction-related environment
Karsli, Orhan; Caran, Şemsettin; Dokuz, Abdurrahman; Çoban, Hakan; Chen, Bin; Kandemir, Raif
The Eastern Pontides is characterized by the many of intrusive bodies formed throughout the late Mesozoic-early Cenozoic. Most of these are I-type granitoids, but here, we present for the first time an A-type pluton from the region to assess source characteristics and geodynamic implications. The A-type Pirnalli pluton has a SHRIMP zircon U-Pb age of 81.2±1Ma. It is composed of granite, syenite and quartz monzonite, and its enclaves are monzonitic in composition with elevated Ga/Al ratios and low Mg# (<42). The pluton is dominantly metaluminous (A/CNK=0.88 to 1.00) and belong to shoshonitic and ultra-potassic series. The samples are highly enriched in LREE and show significant negative Eu (Eu/Eu *=0.33 to 0.92), Ba, Nb, Sr and Ti anomalies in the spidergrams. The host rocks and their enclaves posses quite similar Sr-Nd isotopic compositions (I Sr=0.70693 to 0.70736, ε Nd (81Ma)=-2.6 to -2.0, T DM=0.94 to 1.12Ga), pointing to a lower crustal parental magma with a minor contribution of lithospheric mantle. We hypothesize that upwelling of asthenosphere triggered melting of chemically enriched upper mantle and basic magma formed. Melting of lower crust was provided by the underplating of this basic magma. Mixing between lower crust- and mantle-derived melts at depths of lower crust appears to be most reasonable petrogenetic process responsible for generation of the pluton. Sr-Nd isotope modeling suggests mixing of 82-90% of the lower crustal-derived melt with ~10-18% of the mantle-derived melt. Then the hybrid melt ascended to shallower crustal level and underwent a limited fractionation process to generate a variety of rock types. Our data also suggest that the A-type Pirnalli pluton likely formed at an extensional environment of active continental margin throughout the late Cretaceous. Ongoing extension then led to opening of Black Sea as a back-arc basin further north of the Eastern Pontides.
AtıfScopus95WoS91OpenAlex97İncele - MakaleYalnız künye2015Scopus SJRQ3Evaluation of energy absorption of macro synthetic and steel fiber reinforced concretes; [Evaluarea capacitătii de absorbţie a energiei de către betonul armat cu fibre macro sintetice şi fibre de oţel]
Bolat, Hakan; Şìmşek, Osman
This study aims to determine the energy absorption of concrete slabs (60×60×10cm) using polyester, polypropylene and steel fiber reinforced (SFRC, PYFRC, PPFRC) according to EN 14488-5. Significant differences in the energy absorption were observed between the concrete slabs strengthened with different fibers. The highest gain in energy absorption was observed in SFRC. Furthermore, concrete slabs strengthened with PPFRC and PYFRC showed 23.4% and 14.8% less energy to SFRC. Although the SFRC showed the highest energy absorption under directly negative conditions, it is important to evaluate the durability issues associated with SFRC, such negative conditions.
AtıfScopus7İncele - MakaleYalnız künye2013Scopus SJRQ1Single-Laboratory Validation for the Determination of Aflatoxin B1, B2, G1, and G2 in Foods Based on Immunoaffinity Column and Liquid Chromatography with Postcolumn Derivatization and Fluorescence Detection
Baltacı, Cemalettin; İlyasoğlu, Huri; Yüksel, Ferhat
This study presents a method validation procedure for the determination of aflatoxin B1, B2, G1, and G2 in hazelnut, hazelnut paste, walnut, peanut, pistachio, corn, and wheat. The method consisting of clean-up with immunoaffinity column, high performance liquid chromatography with postcolumn derivatization and fluorescence detection was validated in accordance with Commission Regulation 2004/882/EC. The selectivity, linearity, decision limit, detection capability, detection and quantification limits, precision, recovery, ruggedness, and measurement uncertainty of the method were determined. The limit of detection and limit of quantification values (μg/kg) were: aflatoxin B1, 0. 02, 0. 07; aflatoxin B2, 0. 01, 0. 02; aflatoxin G1, 0. 02, 0. 07; and aflatoxin G2, 0. 01, 0. 03. The relative standard deviation values for the repeatability and within-laboratory reproducibility were below 4 and 5 %, respectively. The recovery values of the spiked samples ranged from 80 to 105 %. These results complied with minimum performance criteria established by regulation 2006/401/EC. Therefore, the procedure can be implemented for the routine analysis of aflatoxins in the studied matrices.
AtıfScopus12WoS11OpenAlex15İncele
