Scopus İndekslenen Yayınlar

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12597/3197

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Crystal structure of methyl (6-(2-fluorobenzoyl)-5-chloro-2-benzoxazolinon-3-yl)-acetate, C17H11ClFNO5
(2006-04-01) Aydin A.; Diindar Y.; Akkurt M.; Büyükgüngör O.; Sahin M.F.
C17H11ClFNO5, monoclinic, P121/c1 (no. 14), a = 7.489(5) Å, b = 18.367(5) Å, c = 11.752(5) Å, β = 94.222(5)°, V = 1612.1 Å3, Z = 4, Rgt(F) = 0.032, wRref(F2) = 0.083, T = 293 K. © 2014 Oldenbourg Wissenschaftsverlag GmbH, Rosenheimer Str. 145, 81671 München. All rights reserved.
Photon mass energy absorption coefficients from 0.4 MeV to 10 MeV for silicon, carbon, copper and sodium iodide
(2006-07-01) Oz H.; Gurler O.; Gultekin A.; Yalcin S.; Gundogdu O.
The absorption coefficients have been widely used for problems and applications involving dose calculations. Direct measurements of the coefficients are difficult, and theoretical computations are usually employed. In this paper, analytical equations are presented for determining the mass energy absorption coefficients for gamma rays with an incident energy range between 0.4 MeV and 10 MeV in silicon, carbon, copper and sodium iodide. The mass energy absorption coefficients for gamma rays were calculated, and the results obtained were compared with the values reported in the literature.
An analytical expression for electron elastic scattering cross section from atoms and molecules in 1.0 keV to 1.0 MeV energy range
(2006-07-31) Yalcin S.; Gurler O.; Gultekin A.; Gundogdu O.
In this Letter, an expression is presented to calculate elastic scattering cross sections for incident electrons as a function of both energy and atomic number in the energy range between 1 keV and 1 MeV for materials with effective atomic number between 3 and 18. The expression we present has a rather simple analytical form which gives accurate results that are in very good agreement with the results calculated by a relativistic partial-wave expansion method. Hence, this equation can be employed accurately and efficiently in a continuous manner, without the need to go through rather large look-up tables, thus making the whole process quick, efficient and removing possible computational errors that may arise from the efforts of interpolation. © 2006 Elsevier B.V. All rights reserved.
Effect of Trachelobdella lubrica (Hirudinea: Piscicolidae) on biochemical and haematological characteristics of black scorpion fish (Scorpaena porcus, Linnaeus 1758)
(2006-10-01) Celik E.; Aydin S.
Black Scorpion fish (Scorpaena porcus Linnaeus 1758) caught during monthly sampling carried out in 2003 in the Dardanelles, Turkey, were examined for the parasite. Trachelobdella lubrica. Infested fish were caught only during December 2003, and the clinical conditions of the 12 fish naturally infested with T. lubrica included fin rot, swollen foci of skin and haemorrhages of the gill and abdominal skin. The prevalence, intensity and abundance of infestation in December 2003 were 40%, 1.75 and 0.70, respectively. The average hepatosomatic index of the infested fish was lower than that of noninfested fish, while the means of the kidney index, splenosomatic index, condition factor, body weight and length were not significantly different between the infested and noninfested fish groups. Blood analysis was conducted on 12 naturally infested and 12 healthy (noninfested) Black Scorpion fish to determine the possible characteristic changes in blood parameters of the fish in response to natural infestation with T. lubrica. Blood leucocyte counts, haematocrit levels, serum total protein, albumin phosphorus, urea, glucose, globulin, cholesterol and triglyceride concentrations in naturally infested Black Scorpion fish were significantly less than those of the noninfested fish (p < 0.05). No significant decreases were observed in the serum sodium, iron, calcium, potassium, chlorine, blood urea nitrogen and creatinine values of the naturally infested fish. Blood haemoglobin values, erythrocyte counts and serum glutamate aspartate aminotransferase (glutamate oxalacetate transaminase), alanine aminotransferase (glutamate pyruvate transaminase), uric acid and very low-density lipids levels of infested fish were insignificantly greater than those in healthy fish. © Springer Science+Business Media B.V. 2006.
3-[6-(2-Chlorobenzoyl)-2-oxo-2,3-dihydro-1,3-benzothiazol-3-yl] propanenitrile
(2006-12-01) Aydin A.; Akkurt M.; Önkol T.; Büyükgüngör O.
The title compound, C17H11ClN2O 2S, crystallizes with two crystallographically independent molecules in the asymmetric unit. In the molecular structure, there are intramolecular weak C-H⋯O hydrogen bonds, which consolidate the molecular conformation. © 2006 International Union of Crystallography All rights reserved.
Fire development from a point source in surface fuels of a mature anatolian black pine stand
(2007-01-01) Küçük O.; Bilgili E.; Baysal I.
A total of 28 line and 24 point-source fires were ignited under varying weather and fuel loading conditions in Anatolian black pine (Pinus nigra J.F.Arnold subsp. nigra var. caramanica (Loudon) Rehder) stands. Relationships between the rate of fire spread and fuel and weather conditions were determined with correlation and regression analyses. The rate of fire spread ranged from 0.12 to 1.20 m min-1 in line fires. In the ignition, transition, and steady state phases of point-source fires, the rate of fire spread ranged from 0.04 to 0.78 m min-1, from 0.11 to 0.59 m min-1, and from 0.08 to 0.99 m min-1, respectively. Surface fuel loading ranged from 1.27 to 2.45 kg m-2 for line fire and from 1.56 to 2.67 kg m-2 for point-source fire. The results showed that the rate of fire spread was closely related to wind speed and fuel moisture content for line and point-source fires. The linear prediction for wind conditions estimates that equilibrium spread rates may be achieved within 25 min after the ignition of point-source fires. © TÜBİTAK.
Three-dimensional neutronic calculations for the fusion breeder apex reactor
(2007-01-01) Şarer B.; Günay M.; Korkmaz M.E.; Hançerlioǧullari A.
Three-dimensional analysis has been made using the MCNP Monte Carlo code and ENDF/B-VI nuclear data. The nuclear characteristics of a fusion-fission hybrid reactor such as tritium breeding ratio, energy multiplication factor, fissile fuel breeding, first wall radiation damage, and heat deposition have been investigated in a liquid first wall, blanket, and shield for the various mixture compositions of molten salt and heavy metals for blanket layer thicknesses of 20, 30, 40, and 50 cm. The neutron flux load at the first wall is assumed to be 10 MW/ m2. The flowing molten salt wall is composed of flibe (Li2BeF4) as the main constituent with increased mole fractions of heavy metals, 2 to 10% ThF4 and UF4. In terms of all parameters, the mixtures with UF4 show better performance than the mixtures with ThF4. The atomic displacement and the helium, tritium production rates remain well below the presumable limits for all mixture compositions of molten salt and heavy metals and thicknesses of the blanket.
Influence of pulping conditions on the properties of anatolian black pine (pinus nigra arnold ssp. Pallassiana) kraft pulps
(2007-01-01) Ateş S.; Kirci H.
Anatolian Black Pine wood chips were pulped using kraft method in laboratory scale batch digester. A series of experimental kraft pulping was carried out according to Central Composite Design (CCD) to investigate the pulping process and to study the effect of its variables (active alkali rate, sulphidity rate and Vroom's H-factor combining temperature and time) on pulp quality and yield. Second order polynomial regression equations using three independent process variables, were found to be approprite for describing kraft pulping of Anatolian Black Pine wood fibers. The derived equations were able to predict the kappa number, viscosity, yield, holocellulose and α-cellulose content of the pulp with adjusted R2 values of 96.1%, 96.8%, 86.3%, 62.5%, 96.1% and 92.2% respectively. H-factor level and the active alkali charge are the most strongly influcing all the dependent variables. In order to obtain acceptable levels of the pulp properties, high sulphidity rate (45%), medium H-factor (1600) and medium alkali concentration (18%) can be used in kraft pulping of Anatolian Black Pine woods. © 2007 Taylor and Francis Group, LLC.
Canopy fuel characteristics and fuel load in young black pine trees
(2007-01-01) Kucuk O.; Saglam B.; Bilgili E.
Crown structure and fuel loading are important factors affecting crown fire occurrence and behavior. This paper reports on the canopy fuel characteristics and regression models to determine Canopy Fuel Loading (CFL) of young black pine (Pinus nigra Arnold) trees. Equations were based on the data from 11 destructively sampled black pine plantation trees. This data was used to develop best equations fit with ordinary least squares procedures that estimate available and total canopy fuel load for young black pine plantation trees. Model fits for available and total canopy fuel load were generally good. Results indicated that available and total canopy fuel load could be easily predicted using diameter at breast height (D), variable. The resulting equations were able to account for 94% of the observed variation in the total canopy fuel load. Average tree canopy fuel load was 8.9 kg. On average 41% of canopy fuel load was allocated to the needle, 13% to the fine branch, 20% to the medium branch, 18% to thick branch and 8% to the very thick branch. Vertical distribution of canopy fuels was variable. Most foliage was found on the main branches of the medium portion of the canopy. The lower and upper portions of the crown had relatively less foliage. The results of the study allowed also for the comparisons of linear and nonlinear equations of biomass estimation commonly used in literature. © 2007 Taylor and Francis Group, LLC.
The radioactivity measurements in soil, coal and water in south Marmara region of Turkey
(2007-02-01) Yalcin S.; Gurler O.
Radioactivity levels were determined in soil, coal and water samples collected from various locations in the south Marmara region of Turkey. The activities in samples were determined using TENNELEC LB 1000-PW detector. The absolute beta activities were observed to vary in the range 0.83 ± 0.06 - 0.50 ± 0.05 for soil in units of Bq g- 1, and 1.284 ± 0.02 - 0.079 ± 0.002 for coal samples in units of Bq g- 1 and 0.74 ± 0.05 - 0.06 ± 0.02 for water in units of Bq l- 1. In addition, gamma spectra of soil and coal samples which have highest level of beta activities were measured by using HpGe detector. 235U, 214Pb, 134Cs, 137Cs, 214Bi and 40K were detected in soil samples. 235U, 214Pb, 134Cs and 214Bi were detected in coal samples. The radioactivity levels in water samples were compared with WHO and ITS recommended levels and the literature values. © 2007 Elsevier Ltd. All rights reserved.
Methyl [6-(2-chlorobenzoyl)-2-oxo-2,3-dihydro-1,3-benzoxazol-3-yl]acetate
(2007-02-01) Aydin A.; Dündar Y.; Akkurt M.; Büyükgüngör O.; Şahin M.F.
In the molecular structure of the title compound, C17H 12ClNO5, the 1,3-benzoxazole ring system makes a dihedral angle of 72.96 (7)° with the benzene ring of the 2-chlorobenzoyl group. In the crystal structure, two intra-molecular C-H⋯O hydrogen bonds influence the molecular conformation. © 2007 International Union of Crystallography All rights reserved.
Thermal properties and crystallinity of thermotropic liquid crystalline copolyesters prepared from poly(ethylene terephtalate) (PET) and rigid aromatic units
(2007-04-01) Tan A.; Altinok H.; Yerlikaya Z.; Aksoy S.
A series of copolyesters were synthesized by melt-polycondensation reaction of poly(ethylene terephtalate) (PET) with various proportions of equimolar compositions of p-acetoxybenzoic acid (p-ABA), hydroquinone diacetate (HQDA) and terephtalic acid (TPA). Viscosity, liquid crystallinity, thermal properties, degree of crystallinity and thermal stabilitiy of these copolyesters were investigated by Ubbelohde viscometer, hot-stage polarized light microscopy (PLM), differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD) and thermogravimetric analysis (TGA), respectively. On the basis of viscosity measurement, it was observed that intrinsic viscosity values of the copolyesters are increased regularly with increasing amounts of aromatic units (p-ABA, HQDA and TPA) in the polymer chain. Thermotropic liquid crystalline behavior was observed in the copolyesters containing over 50mol% of rigid p-ABA/HQDA/TPA aromatic units. DSC analysis of the anisotropic copolyesters revealed broad and weak endotherms associated with the nematic phases, and the melting temperatures were found to be in the processable region. As the mol% of PET in the polymer chain increased, the specific enthalpies of fusion and the degree of crystallinity of the copolyesters were also increased regularly.
Maplets for the area of the unit circle
(2007-05-01) Aktümen M.; Kaçar A.
In this paper, we use Maplets to illustrate several different methods of estimating the area of the unit circle. The first method uses regular inscribed and circumscribed polygons. The second method uses inner, outer, and middle rectangles each of which corresponds to a Riemann sum. The third method uses small, included squares. The Maplets illustrate the area problem from both graphical and numerical points of view, and can be valuable in teaching certain integral concepts and for historical background.
Mosses beta radioactivity in Katirh mountain-Bursa, TURKEY
(2007-08-03) Kahraman A.G.; Kaynak G.; Akkaya G.; Gultekin A.; Gurler O.; Yalcin S.
Mosses are one of the most widely used procedures to determine via plant of radioactive contamination. The high concentrating capacity of mosses may be used as bioindicator of environmental radioactive contamination. In this study, the mosses were collected in region of Katirh Mountain in northwestern Turkey, activities were determined using TENNELEC LB 1000-PW detector. Samples of mosses growing on soil, rock, and tree bark were collected. © 2007 American Institute of Physics.
Antimicrobial activity of some endemic plant species from Turkey
(2007-08-06) Benli M.; Güney K.; Bingöl U.; Geven F.; Yiǧit N.
Six plant extracts obtained from different parts such as the leaves, flowers and seeds of four species of the endemic plants in Turkey were tested on a total of 14 microorganisms, 10 of which were bacterial strains and 4 yeast strains. Verbascum eriocarpum (flower) extract was found to be effective against Staphylococcus aureus; Stachys cretica subsp. anatolica (leaf and flower) and Heracleum paphlagonicum (seed) extracts were found to be effective against Bacillus subtilis; and Alcea apterocarpa (seed and sepal) extract was found to be effective against Pseudomonas aeruginosa. No antimicrobial activity was observed in Heracleum paphlagonicum (leaf) and Alcea apterocarpa (leaf) plant extracts. The minimum inhibitory concentration (MIC) values of the plant extracts were calculated to be between ≥ 0.859 mg/ml and ≥ 110.5 mg/ml and the minimum bacteriocidal concentration (MBC) values were calculated to be between ≥ 3.44 mg/ml and ≥ 132 mg/ml. © 2007 Academic Journals.
Quasiclassical studies of Eley-Rideal and hot-atom reactions on a surface at 94 K: H(D) → D(H) + Cu(1 1 1)
(2007-09-15) Vurdu C.; Özçelik S.; Güvenç Z.
Reactions and reaction dynamics of gas-phase H(or D) atoms with D(or H) atoms adsorbed onto a Cu(1 1 1) surface have been investigated by the quasi-classical molecular dynamics method. To simulate the H(D) → D(H) + Cu(1 1 1) system at a 94 K surface temperature, D(or H) adsorbates were disseminated arbitrarily on the surface of Cu(1 1 1) to form 0.50, 0.28 and 0.18 ML of coverages. The interaction of hydrogen atoms and the surface system is worked out by an LEPS function. LEPS parameters have been determined by using the total energy values which were calculated by a density functional theory (DFT) method and the generalized gradient approximation (GGA) for the exchange-correlation energy for various configurations of one and two hydrogen atoms on the Cu(1 1 1) surface. The Cu(1 1 1) surface, imitated by an embedded-atom method which is a many-body potential parameterized by Voter-Chen, is formed as a multilayer slab. The slab atoms are permitted to move. Various processes, trapping onto the surface, inelastic reflection of the incident projectile and penetration of the adsorbate or projectile atom into the slab, are examined. The dependence of these mechanisms on isotopic replacement has also been analyzed. Considerable contributions of the hot-atom pathways for the product formations are consequently observed. The rate of subsurface penetrations is obtained to be larger than the sticking rate onto the surface. © 2007 Elsevier B.V. All rights reserved.
Calculation of total counting efficiency of a NaI(Tl) detector by hybrid Monte-Carlo method for point and disk sources
(2007-10-01) Yalcin S.; Gurler O.; Kaynak G.; Gundogdu O.
This paper presents results on the total gamma counting efficiency of a NaI(Tl) detector from point and disk sources. The directions of photons emitted from the source were determined by Monte-Carlo techniques and the photon path lengths in the detector were determined by analytic equations depending on photon directions. This is called the hybrid Monte-Carlo method where analytical expressions are incorporated into the Monte-Carlo simulations. A major advantage of this technique is the short computation time compared to other techniques on similar computational platforms. Another advantage is the flexibility for inputting detector-related parameters (such as source-detector distance, detector radius, source radius, detector linear attenuation coefficient) into the algorithm developed, thus making it an easy and flexible method to apply to other detector systems and configurations. The results of the total counting efficiency model put forward for point and disc sources were compared with the previous work reported in the literature. © 2007 Elsevier Ltd. All rights reserved.
2-(6-Oxo-3,4-diphenyl-1,6-dihydro-pyridazin-1-yl)acetic acid
(2007-11-09) Aydin A.; Doǧruer D.; Akkurt M.; Büyükgüngör O.
In the title compound, C18H14N2O3, the pyridazine ring makes dihedral angles of 72.73 (11) and 49.97 (10)° with the two phenyl rings. The dihedral angle between the two phenyl rings is 52.42 (12)°. The crystal structure is stabilized by inter-molecular O - H⋯O and C - H⋯O hydrogen-bonding inter-actions. © International Union of Crystallography 2007.
Comparison of different chemical pulps from wheat straw and bleaching with xylanase pre-treated ECF method
(2008-01-01) Ateş S.; Atik C.; Ni Y.; Gümüşkaya E.
Different pulping processes, kraft-anthraquinone (AQ), bio-kraft, soda-AQ, ALCELL, and FORMACELL were studied for wheat straw. Fungal pre-treatment with Ceriporiopsis subvermispora, white rot fungi, was applied to wheat straw before kraft-AQ pulping, the so-called bio-kraft process. Fiber properties, carbohydrate contents, FT-IR analyses, strength properties of resultant paper, and bleachability characteristics were included to determine the properties of these pulp samples. In addition, the effects of the xylanase pre-treatment on the subsequent Elemental Chlorine Free (ECF) bleaching process were investigated. The results indicated that kraft-AQ pulps from wheat straw exhibited better characteristics than the other pulp samples with lower kappa number, higher carbohydrate content, higher paper strength properties, and better bleachability. The highest kappa number, viscosity, and fiber coarseness were found for organosolv pulp samples; however, these pulps had the lowest carbohydrate contents and strength values and poor bleaching properties. It was concluded that the fungal pre-treatment of wheat straw with C. subvermispora had a positive effect on the bleachability and gave stronger pulp. There was no clear alteration in the crystallinity index of pulp samples based on the FT-IR results. © TÜBİTAK.
Some parameters affecting fire behavior in anatolian black pine slash
(2008-01-01) Küçük O.; Bilgili E.; Saǧlam B.; Başkaya S.; Dinç Durmaz B.
This study presents and discusses the results of a fire behavior study conducted in Anatolian black pine (Pinus nigra J.F. Arnold subsp. nigra var. caramanica (Loudon) Rehder) slash. A total of 30 experimental fires were conducted over 3 years under varying weather and fuel loading conditions in aging slash. Relationships between fire behavior and fuel properties and weather conditions were determined with correlation and regression analyses. Spread rate, fuel consumption, and fire intensity were all related to fuel properties and weather, and ranged from 0.2 to 3.1 m min-1, from 0.71 to 6.65 kg m-2, and from 14.05 to 3961.46 kW m-1, respectively. Fuel loading ranged from 1.56 kg m-2 to 6.96 kg m-2. Differences in fire behavior were clearly shown to be a function of wind speed, fuel moisture, slash age, and fuel loading. Results obtained in this study should be invaluable in overall fire management practices. However, its use should be restricted to the range of conditions within which the data were gathered. © TÜBİTAK.

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