Celik N.,Cukurova University |
Koc E.,OndokuzMayis University
Fibres and Textiles in Eastern Europe | Year: 2010
In the two earlier papers, evaluations were presented on the characteristic parameters determining the behaviour of three industrially produced Wilton-type carpets with different pile materials (wool, acrylic and PP) after a prolonged heavy static loading, and an extended analysis was carried out covering the energy absorption, damping characteristics and hysteresis effect of pile materials on carpet behaviour during recovery. In this study, the same carpets were tested under dynamic loading in order to evaluate and observe the thickness loss and carpet behaviour under dynamic loads. The results are given and discussed in this paper.
Keles G.C.,OndokuzMayis University
The West Indian medical journal | Year: 2013
Elevated levels of platelet activating factor (PAF), a potent inflammatory mediator in periodontal disease and decreased PAF levels following periodontal surgical therapy have been previously detected in gingival tissues and gingival crevicular fluid (GCF). Platelet activating factor acetylhydrolase (PAF-AH) is a calcium-independent phospholipase A2 that catalyses the hydrolysis of PAF, thereby inactivating this mediator The hypothesis, a relationship between activity of PAF-AH and healing following periodontal therapy, was tested by detecting activity of PAF-AH in GCF samples collected from sites that had undergone phase I periodontal therapy with generalized chronic periodontitis. Twenty patients with generalized chronic periodontitis were divided into two groups (n = 10): group 1 with probing pocket depth (PPD) 4-5 mm and group 2 with PPD > or = 6-8 mm. Clinical parameters were recorded and GCF was sampled before phase I periodontal therapy and at the 2nd, 7th, 14th, 21st and 28th day follow-up evaluation visits. Activity of PAF-AH in GCF was analysed by enzyme-linked immunosorbent assay (ELISA). Probing pocket depth at the 21st and 28th day in group 1, and PPD at the 14th, 21st and 28th day in group 2 were significantly decreased when compared to the baseline values (p < 0.001). Activity of PAF-AH (micromol/ml) was significantly decreased at the 7th, 14th, 21st and 28th day following phase I periodontal therapy in both groups 1 and 2 compared to the baseline values (p < 0.05). Platelet activating factor acetylhydrolase is detectable in GCF by ELISA and showed a continuous decrease following phase I periodontal therapy. Changes in the PAF-AH activity would be a progressive marker of periodontal healing to evaluate the success of periodontal therapies.
Bektas S.,OndokuzMayis University
Boletim de Ciencias Geodesicas | Year: 2015
In this paper, we present techniques for ellipsoid fitting which are based on minimizing the sum of the squares of the geometric distances between the data and the ellipsoid. The literature often uses “orthogonal fitting” in place of “geometric fitting” or “best-fit”. For many different purposes, the best-fit ellipsoid fitting to a set of points is required. The problem of fitting ellipsoid is encountered frequently in theimage processing, face recognition, computer games, geodesy etc. Today, increasing GPS and satellite measurements precision will allow usto determine amore realistic Earth ellipsoid. Several studies have shown that the Earth, other planets, natural satellites, asteroids and comets can be modeled as triaxial ellipsoids Burša and Šima (1980), Iz et al (2011). Determining the reference ellipsoid for the Earth is an important ellipsoid fitting application, because all geodetic calculations are performed on the reference ellipsoid. Algebraic fitting methods solve the linear least squares (LS) problem, and are relatively straightforward and fast. Fitting orthogonal ellipsoid is a difficult issue. Usually, it is impossible to reach a solution with classic LS algorithms. Because they are often faced with the problem of convergence. Therefore, it is necessary to use special algorithms e.g. nonlinear least square algorithms. We propose to use geometric fitting as opposed to algebraic fitting. This is computationally more intensive, but it provides scope for placing visually apparent constraints on ellipsoid parameter estimation and is free from curvature bias Ray and Srivastava (2008). © 2015, Universidade Federal do Parana. All rights reserved.
Guler A.,OndokuzMayis University
Apidologie | Year: 2010
The objectives of this study were to (1) determine the effects of imported commercial queen bees from different geographical origin subspecies on the morphological variation of native honeybee population of the Turkeli area; and (2) apply a model to identify and predict the use of commercial queens subspecies. Standard classification function, discriminant function, and constant coefficients for 41 morphological characteristics were determined for two geographic Turkish honeybee subspecies (Apis mellifera anatoliaca and A. m. caucasica) used intensively for commercial queen rearing. Then, the morphological characteristics of unknown worker bee samples from the Turkeli area - where commercial queen bee usage is common - were investigated. The model showed that the area was subject to genetic mixing because of commercial queen usage. The subspecies of 15 unknown test samples were predicted with 100% confidence, and the native bees from 25 of 30 samples from the Turkeli area were successfully predicted using the model developed. Using the model proved that there was a commercial queen bee introduction into the Turkeli area, mainly from the A. m. caucasica subspecies. © 2010 INRA/DIB-AGIB/EDP Sciences.
Orkun M.O.,OndokuzMayis University |
Kuleyin A.,OndokuzMayis University
Environmental Progress and Sustainable Energy | Year: 2012
The removal of chemical oxygen demand (COD) from landfill leachate by electro-coagulation (EC) using iron sacrificial anode has been investigated. The process performance is analyzed in terms of COD removal efficiency and the important cost-related parameters such as electrode and energy consumptions, as a function of initial pH, conductivity, current density, and operation time. The optimum COD removal (65.85%) was obtained with typical operating conditions: current density, 30 mA/cm 2; operation time, 180 min; conductivity, 16.4 ms/cm; and initial pH, 6.54. At these conditions, the electrode and energy consumptions during the electrolysis were determined as 0.418 kg COD/kg Al and 11.092 kWh/kg COD, respectively. In addition, the EC and Fenton processes are applied together referred to as the electro-Fenton process in the literature for the removal of COD from landfill leachate and effect of operation time and hydrogen peroxide concentration is examined. The process was very fast in the first 15 min, and then it slowed down till it was complete in 60 min. An optimum COD removal efficiency of 74.21% was obtained at 5000 ppm hydrogen peroxide dosage and 60 min. © 2010 American Institute of Chemical Engineers.