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Koleksiyondaki öğeler
- MakaleAçık Erişim2012Scopus SJRQ2Dehydrated hazelnut husk carbon: A novel sorbent for removal of Ni(II) ions from aqueous solution
Sivrikaya, Sezen; Albayrak, Sinem; Imamoglu, Mustafa; Gundogdu, Ali; Duran, Celal; Yildiz, Hulya
The present study has been performed to examine the adsorption ability of novel sorbent dehydrated hazelnut husk carbon (DHHC) towards Ni(II) ions from aqueous solution using the batch adsorption technique. The effective factors such as initial pH of the aqueous solution, contact time, initial Ni(II) concentration, adsorbent dosage, and temperature were investigated. The studies were also conducted to understand the effect of some co-existing ions which may be present in aqueous solutions. DHHC showed good adsorption potential for Ni(II) ions. The optimum initial pH value was selected as 5.0. The experimental data fitted well to the Langmuir adsorption isotherm model. Among the kinetic models tested for the adsorption of Ni(II), the pseudo-second-order model showed a good fit of the kinetic data. The thermodynamic parameters including the Gibbs free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) changes indicated that the adsorption of Ni(II) ions onto DHHC was feasible, spontaneous, and exothermic in the temperature range of 25-55°C. The results of this study showed the effectiveness and feasibility of DHHC for the removal of Ni(II) ions from aqueous solution.
AtıfScopus33WoS33OpenAlex33
İncele - BildiriYalnız künye2011The control of an automatic door using fuzzy logic
Sümbül, Harun; Coşkun, Akif; Taşdemir, Muharrem
In this paper; a fuzzy logic have designed to the control of an automatic door. Input status (WS: Walking Speed and DD: Distance Door) and the output status (DOS: Door Opening Speed) is determined. According to these statuses, rule bases (25 rules) have obtained. And the rules bases have been processed by a fuzzy logic and have tried to control of an automatic door. As a result; in this study, we have obtain very good results in control of an automatic door with fuzzy logic. The results of analyses have indicated that the controls performed with fuzzy logic provided both less time, less probability and reliable, consistent controls and that are feasible to in real.
AtıfScopus8OpenAlex6İncele - MakaleYalnız künye2010Scopus SJRQ3Assessment of medical home care needs in Turkish population
Sahinoz, Saime; Sahinoz, Turgut; Eker, Hasan Huseyin; Unlu, Suleyman Ersin
Objective: To determine the home healthcare needs of the elderly so as to develop proper home Healthcare Services. Methodology: This descriptive study was carried out in a county of Kocaeli province-Turkey. Data was collected through a specially designed questionnaire through face to face interview technique. The data were analyzed by the computer using the SPSS package program. Chi-square test was used for the statistical analysis. Results: This study showed that 14.6% of the population had at least one diagnosed disease. Among them, 1.8% was disabled, 4.1% was elderly and 1.1% of the households were in need of home care services. Conclusions: Home care needs were found to be low in this study. Its main cause was that elderly population was not aware of the availability of such a service in the country.
- MakaleYalnız künye2011Scopus SJRQ2A proficiency test scheme for the quality control of black tea and development of quality control material for internal quality control
Baltaci, Cemalettin; Ilyasoǧlu, Huri; Sarikaya, Sevim Beyza Öztürk; Cavrar, Sevda; Yayli, Nurettin
A proficiency test (PT) was organized for quality control analysis of black tea. Test materials for the analyses of total content of powder tea, moisture, total ash, acid-insoluble ash, water-soluble ash, alkalinity of water-soluble ash, water extract, crude fiber and caffeine were sent to the participant laboratories (n:43) in 2009. The assigned value, standard deviation of the parameters and z-scores of the participant laboratories were calculated using the data reported by the participants. The percentage of the reported results for analytes was found to be ranged from 67.5 to 100%. Acceptable z-scores were achieved by 80.5-97.5% of the participant laboratories. More than 15% of unacceptable results were obtained for acid-insoluble ash and caffeine analyses. The quality control material for quality control analysis of black tea was developed from the remaining material.
AtıfScopus4WoS3OpenAlex3İncele - MakaleYalnız künye2011Scopus SJRQ2Polyphenol contents and antioxidant properties of medlar (Mespilus germanica L.)
Gülçin, Ilhami; Topal, Fevzi; Sarikaya, S. Beyza Öztürk; Bursal, Ercan; Bilsel, Gökhan; Gören, Ahmet C.
Medlar is the fruit of Mespilus germanica L. in the family of Rosaceae. The present study outlines that the native medlar (Mespilus germanica L.) fruits an extremely rich source of antioxidants. In this study, antioxidant and antiradical property of medlar fruits were evaluated. Total phenolics and flavonoids amounts in lyophilized extract of medlar (LEM) fruits were calculated as gallic acid and quercetin equivalents, respectively. Antioxidant and radical scavenging activity of LEM were investigated using different in vitro assays including 1,1-diphenyl-2-picryl-hydrazyl (DPPH·), N,N-dimethyl-p-phenylenediamine (DMPD•+), and superoxide anion radicals (O2•-) scavenging activity, hydrogen peroxide (H2O2), ferric ions (Fe 3+) and cupric ions (Cu 2+) reducing ability, Fe 3+ -TPTZ reducing ability, ferrous ions (Fe2+) chelating activity as trolox equivalent. In addition, quantitative amounts of caffeic acid, ferulic acid, syringic acid, ellagic acid, quercetin, α-tocopherol, pyrogallol, p-hydroxybenzoic acid, vanillin, p-coumaric acid, gallic acid and ascorbic acid in LEM were detected by high performance liquid chromatography and tandem mass spectrometry (LC-MS/MS). The presence of these antioxidant compounds can be considered as a quality parameter for edible medlar fruits.
AtıfScopus151WoS138İncele - MakaleAçık Erişim2014Scopus SJRQ2High order approximation of the inverse elliptic problem with dirichlet-neumann conditions
Ashyralyyev, Charyyar
Inverse problem for the multidimensional elliptic equation with Dirichlet-Neumann conditions is considered. High order of accuracy difference schemes for the solution of inverse problem are presented. Stability, almost coercive stability and coercive stability estimates of the third and fourth orders of accuracy difference schemes for this problem are obtained. Numerical results in a two dimensional case are given.
AtıfScopus35WoS31OpenAlex35İncele - MakaleAçık Erişim2012Scopus SJRQ1Assessment of permeability and injection depth at the Atasu dam site (Turkey) based on experimental and numerical analyses
Gurocak, Zulfu; Alemdag, Selcuk
This study was performed in order to evaluate the permeability of the basalts and pyroclastics and the maximum depth of grout injection at the Atasu dam site, Turkey, using the equations of Kiraly and Hoek and Bray based on values obtained from Lugeon tests. In order to evaluate maximum discharge values and depth of injection, seepage analyses were performed using the finite element technique for each 10 m up to 100 m. The results indicate that to establish an impermeable zone at the dam site, the depth of injection should be taken as 50 m for the left and right slopes and 40 m for the river bed.
AtıfScopus45WoS37OpenAlex49İncele - BildiriYalnız künye2012Using 3D models from multidetector computed tomography images for diagnostic of Hallux-valgus
Catal, Hatice; Corumluoglu, Ozsen
Medical image processing techniques is often used in medicine or some engineering fields. In this study, we used basic techniques of metric digital image processing. Axial MDCT (Multidetector Computed Tomography) Ballerina's feet images were used to form 3D models by 3D-Doctor software. The virtual 3D models are in high accuracy. Hallux-valgus angles were calculated and recorded by using these 3D virtual models. We hope that the results from the biometric and reconstructive techniques carried out in this work will contribute to the present knowledge in medicine especially on ballerina's foot health and digital image processing in this area.
AtıfScopus1İncele - MakaleAçık Erişim2012Scopus SJRQ2The difference problem of obtaining the parameter of a parabolic equation
Ashyralyyev, Charyyar; Demirdag, Oznur
The boundary value problem of determining the parameter p of a parabolic equation ′(t)+A(t)=f(t)+p(0≤t≤1),(0)=,(1)= in an arbitrary Banach space E with the strongly positive operator A is considered. The first order of accuracy stable difference scheme for the approximate solution of this problem is investigated. The well-posedness of this difference scheme is established. Applying the abstract result, the stability and almost coercive stability estimates for the solution of difference schemes for the approximate solution of differential equations with parameter are obtained.
AtıfScopus21WoS18OpenAlex16İncele - MakaleYalnız künye2013Scopus SJRQ1The effect of the spew fillet on an adhesively bonded single-lap joint subjected to bending moment
Akpinar, Salih; Doru, Muhammet Onur; Özel, Adnan; Aydin, Murat Demir; Jahanpasand, Hamed Ghaffarzadeh
The mechanical behaviors of an adhesively bonded single lap joint with a spew fillet under bending moment, where the widths of the upper-adherend and lower-adherend are not the same, were studied experimentally and numerically. Using AA2024-T3 aluminum alloy as adherend and DP460 as paste adhesive, four different types of single-lap joint samples (without spew fillet, with spew fillet at joint edges, with spew fillet at joint ends and with spew fillet at all edges) were produced for experimental studies. Stress analyses in the single-lap joint were performed with a three dimensional non-linear finite element method by considering the geometrical non-linearity and non-linear material behaviors of both adhesives (DP460) and adherend (AA2024-T3). The single lap joint with the spew fillet with different widths had a significant effect on the stress distribution. Additionally, the spew fillet increased the load carrying capacity of the joint and decreased the stress concentration of the joint.
AtıfScopus55WoS51OpenAlex57İncele - MakaleYalnız künye2012Scopus SJRQ3Elemental and radioactivity analyses of mosses collected in hatila valley national park - Eastern black sea region of Turkey
Koz, Bahadir; Cevik, Ugur; Celik, Necati
This study was performed in one of the most important parks of Turkey, the Hatila national park, where a gold mining activity is planned to be conducted. For this purpose, 40 moss samples were collected for heavy metal and radioactivity measurements. A radioisotope excited Xray fluorescence analysis using the method of multiple standard additions was applied for the elemental analysis of mosses collected in Hatila valley national park in the Eastern Black Sea region of Turkey. An annular 50 mCi 241Am radioactive source and annular 50 mCi 55Fe radioactive sources were used for excitation of characteristic K-X rays. An Si(Li) detector which had a 147eV full width at half maximum for 5.9 keV photons was used for intensity measurements. A qualitative analysis of spectral peaks showed that the samples contained potassium, calcium, titanium, iron, tin and barium with average concentrations of 230, 5340, 450, 70, 4 and 33 mg.kg -1, respectively. 137Cs and 40K using gamma-ray spectroscopy were determined in 40 moss species collected from the Hatila valley national park. Average activity concentrations of 40K and 137Cs were found to be 103 and 272 Bq.kg -1, respectively. As the region was shown to be heavily contaminated by the Chernobyl accident, the high concentration of 137Cs could be due to this accident. The results are compared with those obtained in different parts of the world where gold mining activities are being conducted. The possible consequences of these results are briefly discussed from the point of potential hazards to ecology and human health.
AtıfScopus2WoS2İncele - MakaleAçık Erişim2011Scopus SJRQ1Early abyssal- and late SSZ-type vestiges of the Rheic oceanic mantle in the Variscan basement of the Sakarya Zone, NE Turkey: Implications for the sense of subduction and opening of the Paleotethys
Dokuz, Abdurrahman; Uysal, Ibrahim; Kaliwoda, Melanie; Karsli, Orhan; Ottley, Chris J.; Kandemir, Raif
The boundary between the Gondwana and Laurussia, or a terrane separated from it, is traced by a suture recording the closure of the Rheic ocean in the Pulur, Beyçam and Kurtoǧlu areas of the eastern Sakarya Zone of Turkey. Pulur lherzolite has a lower Cr# [100Cr/(Cr+Al)=5-37] of the spinel and slightly enriched flat medium-heavy rare earth element (M-HREE) whole-rock pattern typical for those of the fertile abyssal-type lherzolite. By contrast, the Beyçam harzburgite displays the mineralogical and geochemical features of a moderately depleted residue at a supra subduction zone (SSZ). Some of spinels from the Beyçam peridotites show TiO2 contents (0.15-0.48wt.%) identical to a later interaction with a melt of island-arc tholeiite (IAT) composition. Meta-basalt from the Beyçam area is the representative of such a melt and displays the whole-rock M-HREE pattern of a complementary product of the Beyçam harzburgite. Data presented in this study support the primarily northward directed closure of the Rheic ocean, but suggest that the Variscan basement in the eastern part of the Sakarya Zone consists of mantle peridotites formed in a south-vergent SSZ. This dual polarity of subduction in the Rheic ocean, at least in the second half of its closure, is also favored by the geological structure and lithological diversity of the Variscan rocks. These are: (1) spatial distribution of the peridotites, e.g., SSZ-type harzburgites to the north and abyssal-type lherzolites to the south, (2) lack of high-pressure metamorphic rocks, (3) decrease in the degree of Variscan metamorphism toward the north, and (4) emplacement of Variscan syn-collisional magmatism into the low grade metamorphic rocks to the north. Paleotethys was the other ocean of the region created in the Late Paleozoic. Northward subduction of the Rheic ocean from Early Devonian to Early Carboniferous appears to be the most plausible mechanism responsible for the opening of Paleotethys. In this scenario the Paleotethys is envisaged as a back-arc basin opened to the north in the wake of separated terranes from Laurussia. Onset of trench-Rheic mid-ocean ridge collision in the Early Devonian along the northern margin of Laurussia has been proposed to account for the initiation of SSZ-type subduction to the south. The short duration of this subduction appears insufficient to open a fully developed back-arc basin to the south because the elimination of Rheic mid-ocean ridge to the north accelerated the oceanic closure.
AtıfScopus56WoS52OpenAlex51İncele - MakaleYalnız künye2012Scopus SJRQ2Performance and emission studies of castor bean (Ricinus Communis) oil biodiesel and its blends with diesel fuel
Özcanli, M.; Serin, H.; Saribiyik, O.Y.; Aydin, K.; Serin, S.
An experimental study was conducted to evaluate the use of various blends of castor (Ricinus Communis) oil methyl ester with diesel fuel. Performance and exhaust emissions of castor oil biodiesel with diesel fuel in a commercial compression ignition engine were presented in this study. Biodiesel produced from castor oil was blended with diesel fuel at the volumetric ratios of 5% (B5), 10% (B10), 25% (B25), 50% (B50), and 100% (B100). Fuel properties of castor oil methyl ester and its blends with diesel fuel were stated. The performance results showed that blends of castor oil methyl ester with diesel provided an increase on brake specific fuel consumption and a small decrease on brake power output. Compared with diesel fuel, diesel-castor oil methyl ester blends showed that while the carbon monoxide and carbon dioxide emissions became reduced; the oxides of nitrogen emissions observed higher than diesel fuel emission characteristics. Test results showed that B25 was determined as a suitable alternative fuel for diesel engines.
AtıfScopus40WoS35OpenAlex39İncele - MakaleYalnız künye2013Scopus SJRQ2Organic geochemical characteristics and depositional environments of the eocene deposits in the eastern black sea region, NE Turkey
Eker, C.S.
Type of organic material, thermal maturity, depositional environment, and source rock potential of Eocene aged clastic rocks of the Eastern Black Sea Region were investigated. Based on total organic carbon values, clastic rocks range from weak-good source rock. Samples contain a mixture of Type I-Type III kerogen. Based on T max values, Eocene aged clastic rocks were thermally mature. Moretane/hopane ratio of samples <0.15, 22S/(22S + 22R) homohopane (C32), and 20S/(20S + 20R) sterane (C29) maturity parameters were equal or very close to equilibrium value of oil generation. The deposition environment was transitional marine environment and clastic rocks do not have the potential to form hydrocarbon.
AtıfScopus5WoS5OpenAlex8İncele - MakaleYalnız künye2014Scopus SJRQ2K-Ar dating, whole-rock and Sr-Nd isotope geochemistry of calc-alkaline volcanic rocks around the Gümüşhane area: Implications for post-collisional volcanism in the Eastern Pontides, Northeast Turkey
Aslan, Zafer; Arslan, Mehmet; Temizel, Irfan; Kaygusuz, Abdullah
Volcanic rocks from the Gümüşhane area in the southern part of the Eastern Pontides (NE Turkey) consist mainly of andesitic lava flows associated with tuffs, and rare basaltic dykes. The K-Ar whole-rock dating of these rocks range from 37.62 ± 3.33 Ma (Middle Eocene) to 30.02 ± 2.84 Ma (Early Oligocene) for the andesitic lava flows, but are 15.80 ± 1.71 Ma (Middle Miocene) for the basaltic dykes. Petrochemically, the volcanic rocks are dominantly medium-K calc-alkaline in composition and show enrichment of large ion lithophile elements, as well as depletion of high field strength elements, thus revealing that volcanic rocks evolved from a parental magmas derived from an enriched mantle source. Chondrite-normalized rare-earth element patterns of the volcanic rocks are concave upwards with low- to-medium enrichment (LaCN/LuCN = 3.39 to 12.56), thereby revealing clinopyroxene- and hornblende-dominated fractionations for andesitic-basaltic rocks and tuffs, respectively. The volcanic rocks have low initial 87Sr/86Sr ratios (0.70464 to 0.70494) and εNd(i) values (+1.11 to +3.08), with Nd-model ages (TDM) of 0.68 to 1.02 Ga, suggesting an enriched lithospheric mantle source of Proterozoic age. Trace element and isotopic data, as well as the modelling results, show that fractional crystallization and minor assimilation played an important role in the evolution of the volcanic rocks studied. The Eocene to Miocene volcanism in the region has resulted from lithospheric delamination and the associated convective thinning of the mantle, which led to the partial melting of the subduction-metasomatized lithospheric mantle.
AtıfScopus66WoS51OpenAlex64İncele - MakaleYalnız künye2014Scopus SJRQ1The effects of macro synthetic fiber reinforcement use on physical and mechanical properties of concrete
Bolat, Hakan; Şimşek, Osman; Çullu, Mustafa; Durmuş, Gökhan; Can, Ömer
Attempts to find a construction material having increased strength, ductility, toughness, and durability have led to interest in high performance fiber reinforced concrete. The use of such materials increases day by day. When the fibers are distributed in a homogeneous way and used in appropriate quantity inside the concrete, they reduce cracks, contribute to tensile strength, toughness, ductility and durability, and improve other mechanical properties. In this study, four types of concrete were produced: steel fiber (SFRC), polyester fiber (PYFRC), polypropylene fiber (PPFRC) reinforced concrete and a reference sample made of plain concrete (R1); these were then compared to one another. The ratio of fibers was used 4.25% of volume of concrete. The effects of the different types of fiber on hardened concrete were determined by conducting physical and mechanical experiments. Compressive strength, surface hardness, ultrasonic pulse velocity, carbonation, abrasion, capillarity and freeze-thaw resistance experiments were conducted on hardened concretes. SFRC had higher 12.4%, PYFRC 3.4% higher and PPFRC 4.3% lower compressive strength with respect to R1. PPFRC showed 8.04% higher compressive strength than R1 when it was determined by the surface hardness method. SFRC showed 5.4% higher compressive strength than R1 when we applied the ultrasonic pulse velocity method. In the abrasion experiment, the highest abrasion was found in SFRC with ∼0.5%, while the lowest was found in PPFRC at ∼0.18%. The highest and lowest amount of capillary water absorption was seen in R1 and PYFRC, respectively. In a carbonation experiment, SFRC was determined ∼130.8% higher than R1. It was concluded that the types of fiber used for reinforcement influenced the physical and mechanical properties of the concrete.
AtıfScopus137WoS123OpenAlex147İncele - MakaleAçık Erişim2011Scopus SJRQ4Frequency optimization of laminated skewed open cylindrical shells
Topal, Umut; Uzman, Ümit
This paper deals with frequency optimization of symmetrically laminated skewed open cylindrical shells. The design objective is the maximization of the fundamental frequency and the design variable is the fiber orientations. The firstorder shear deformation theory (FSDT) is used for the finite element solution of the shells. The modified feasible direction (MFD) method is used for the optimization routine. For this purpose, a program based on FORTRAN is used. Finally, the numerical analysis is carried out to investigate the effect of skew angles, length to radius ratios, subtended angle and boundary conditions on, the optimal designs and the results are compared.
AtıfScopus6WoS5OpenAlex7İncele - MakaleAçık Erişim2015Scopus SJRQ3Some aspects of Lqυ (Rd)∩Wp,wk (Rd)
Güngör, Nihan; Sağir, Birsen
Let 1≤q, p < ∞ and υ,w be Beurling's weight functions on Rd. In this article we deal with harmonic properties of intersection space Aq,pk,υ,w (Rd) = Lqυ (Rd) ∩ Wp,wk (Rd) defined by aid of weighted Lebesgue space Lqυ (Rd) and weighted Sobolev space Wp,wk (Rd). We research the inclusions and inequalities between the spaces Aq,pk,υ,w (Ω) where Ω ⊂ Rd be an open set. Finally, we proved that the spaces M (A1,pk,w (Rd), L1w (Rd)) can be identified with the weighted spaces of bounded measures Mw (Rd).
- MakaleYalnız künye2014Scopus SJRQ1LA-ICP MS zircon dating, whole-rock and Sr-Nd-Pb-O isotope geochemistry of the Camiboǧazi pluton, Eastern Pontides, NE Turkey: Implications for lithospheric mantle and lower crustal sources in arc-related I-type magmatism
Kaygusuz, Abdullah; Arslan, Mehmet; Siebel, Wolfgang; Sipahi, Ferkan; Ilbeyli, Nurdane; Temizel, Irfan
Late Cretaceous I-type plutons are widespread in the Eastern Pontides, NE Turkey. The studied Camiboǧazi pluton is a composite pluton consisting of diorite, tonalite, monzodiorite, monzonite, quartz monzonite, granite, and mafic microgranular enclaves (MMEs). Laser ablation ICP-MS U-Pb dating of zircon yielded crystallization ages of 76.21±0.79Ma, 75.65±0.50Ma, 75.04±0.83Ma, and 74.73±0.86Ma for diorite, monzodiorite, monzonite, and granite, respectively. The rocks of the pluton have I-type, high-K to shoshonitic and metaluminous character, displaying whole-rock geochemical features of arc-related granites. They are enriched in large-ion lithophile and light rare-earth elements, and depleted in high-field-strength elements. Major element variations can be attributed to fractionation of plagioclase, clinopyroxene, hornblende, and Fe-Ti oxides. The rocks show considerable variation in 87Sr/86Sr(i) (0.70498 to 0.70622), εNd(i) (-2.79 to -0.36), δ18O values (+6.3 to +11.4) and Nd model ages (TDM) (0.81Ga to 1.26Ga). Besides, they have (206Pb/204Pb)=18.44-19.09, (207Pb/204Pb)=15.64-15.69, and (208Pb/204Pb)=38.37-38.89. Although isotope signatures of the mafic microgranular enclaves (MMEs) (87Sr/86Sr(i)=0.70551 to 0.70622; εNd(i)=-2.9 to -1.23; δ18O=+8.3 to +9.7) are largely similar to the host rocks, MMEs are characterized by relatively high Mg-numbers (32-36), low contents of SiO2 (52-56wt.%) and low ASI (0.7-0.9). Estimated crystallization temperatures for the rocks of the pluton range from 735±58°C to 844±24°C and a shallow intrusion depth (<10km) is estimated from Al-in-hornblende thermobarometry. Whole-rock geochemical and isotopic data suggest magma generation by dehydration melting of an amphibolite-type lower crustal component with additional input of a subcontinental lithospheric mantle component. Furthermore, Sr-Nd isotope mixing model reveals ~30% to 40% lower crustal magma contribution to the mantle component.
AtıfScopus87WoS76OpenAlex83İncele - BildiriYalnız künye2012Finite difference method for the reverse parabolic problem with Neumann condition
Ashyralyyev, Charyyar; Dural, Ayfer; Sozen, Yasar
A finite difference method for the approximate solution of the reverse multidimensional parabolic differential equation with a multipoint boundary condition and Neumann condition is applied. Stability, almost coercive stability, and coercive stability estimates for the solution of the first and second orders of accuracy difference schemes are obtained. The theoretical statements are supported by the numerical example.
AtıfScopus16WoS15OpenAlex11İncele
