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Hekimoglu O.Z.,Mugla University
International Journal of Rock Mechanics and Mining Sciences | Year: 2014

Slow cutting rate, tool wear and shallow depth of cuts are important practical issues observed with the commercially available chain saw machines. This paper is concerned with increasing the performance of current chain saw machines in terms of cutting rate and reduced tool wear, and investigates aspects of very shallow depth cutting, through changes in the original tool lacing of machines operating at various quarries. The cutting rate was observed to increase and wear on the leading tool was significantly reduced under similar cutting conditions when a partial modification was carried out to the manufacturers[U+05F3] original tool lacing. It was concluded that the tool lacing employed on current machines can be improved, with the power installed on current chain saw machines not being sufficient for the picks to benefit from deeper depth of cuts. It was further found that the basic principles of tool lacing fundamentals for conventional rock cutting machines are also valid for chain saws. © 2014 Elsevier Ltd. Source

Bal U.,Mugla University
Biomedical Optics Express | Year: 2012

Photon shot noise is the main noise source of optical microscopy images and can be modeled by a Poisson process. Several discrete wavelet transform based methods have been proposed in the literature for denoising images corrupted by Poisson noise. However, the discrete wavelet transform (DWT) has disadvantages such as shift variance, aliasing, and lack of directional selectivity. To overcome these problems, a dual tree complex wavelet transform is used in our proposed denoising algorithm. Our denoising algorithm is based on the assumption that for the Poisson noise case threshold values for wavelet coefficients can be estimated from the approximation coefficients. Our proposed method was compared with one of the state of the art denoising algorithms. Better results were obtained by using the proposed algorithm in terms of image quality metrics. Furthermore, the contrast enhancement effect of the proposed method on collagen fi{dotless}ber images is examined. Our method allows fast and efficient enhancement of images obtained under low light intensity conditions. © 2012 Optical Society of America. Source

Satureja thymbra was used as a spice in Anatolia and Greece. The essential oil and the methanol extract of Satureja thymbra were evaluated for cholinesterase inhibitory effects against acetylcholinesterase and butyrylcholinesterase which are the chief enzymes of Alzheimer's disease. The antioxidative effects of the essential oil and the extract were also determined by using β-carotene-linoleic acid, DPPH •-scavenging, ABTS •+-scavenging, and CUPRAC assays. The GC and GC-MS analyses of the essential oil afforded twenty-five compounds. The identified main compounds of the essential oil, carvacrol (34.6%), γ-terpinene (22.9%), p-cymene (13.0%) and thymol (12.8%) were also tested in the same manner. The experimental findings indicated that the compounds, except p-cymene, were active in both activity tests. Moreover, the extract (IC 50:13.1 ± 0.23 μg/ml), the oil (IC 50:26.7 ± 0.56 μg/ml) and γ-terpinene (IC 50:11.9 ± 0.21 μg/ml) exhibited a good lipid peroxidation inhibitory activity. In addition, the possible mechanism of lipid peroxidation inhibitory activity of γ-terpinene was also discussed. © 2012 Elsevier Ltd. All rights reserved. Source

Yuzbasi S.,Mugla University
Mathematical Methods in the Applied Sciences | Year: 2013

In this article, a numerical technique is presented for the approximate solution of the Bagley-Torvik equation, which is a class of fractional differential equations. The basic idea of this method is to obtain the approximate solution in a generalized form of the Bessel functions of the first kind. For this purpose, by using the collocation points, the matrix operations and a generalization of the Bessel functions of the first kind, this technique transforms the Bagley-Torvik equation into a system of the linear algebraic equations. Hence, by solving this system, the unknown Bessel coefficients are computed. The reliability and efficiency of the proposed scheme are demonstrated by some numerical examples. Copyright © 2012 John Wiley & Sons, Ltd. Source

Bal U.,Mugla University
Biomedical Optics Express | Year: 2015

We propose a robust method for automated computation of heart rate (HR) from digital color video recordings of the human face. In order to extract photoplethysmographic signals, two orthogonal vectors of RGB color space are used. We used a dual tree complex wavelet transform based denoising algorithm to reduce artifacts (e.g. artificial lighting, movement, etc.). Most of the previous work on skin color based HR estimation performed experiments with healthy volunteers and focused to solve motion artifacts. In addition to healthy volunteers we performed experiments with child patients in pediatric intensive care units. In order to investigate the possible factors that affect the non-contact HR monitoring in a clinical environment, we studied the relation between hemoglobin levels and HR estimation errors. Low hemoglobin causes underestimation of HR. Nevertheless, we conclude that our method can provide acceptable accuracy to estimate mean HR of patients in a clinical environment, where the measurements can be performed remotely. In addition to mean heart rate estimation, we performed experiments to estimate oxygen saturation. We observed strong correlations between our SpO2 estimations and the commercial oximeter readings. © 2014 Optical Society of America. Source

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