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SDU
Isparta, Turkey

Slechta J.,Czech Technical University | Juhl P.M.,SDU
Akustika | Year: 2014

The purpose of this paper is to present an algorithm for the calculation of the sound attenuation caused by a thin straight noise barrier in homogeneous conditions of sound propagation. The development of the algorithm was done with the boundary element method (the BEM) and the least squares method. The BEM was used to obtain the data, i.e. to calculate the sound attenuation by a noise barrier in different situations. The curve fitting was processed in Matlab with the tool for non-linear curve fitting tasks in the least square sense. The curve fitting was done for 1/1 octave band centre frequencies usually considered in the road traffic noise. The new algorithm was compared with commonly used engineering methods (NMPB-Routes-1996, formula of Kurze & Anderson and Deygout's method). The values of the sound attenuation estimated by the presented algorithm are except low frequencies lower than the values calculated by Deygout and higher than the values calculated by NMPB-Routes-1996 and Kurze & Anderson. Source


Pacaci S.,SDU
International Journal of Engineering Education | Year: 2012

DC-DC converters have a wide usage as the driver circuit of direct current (DC) motors. This has necessitated sensitive speed controls to be made on DC motors. Classical controllers have lower performance due to the non-linear features of DCmotors, such as saturation and friction. The Neural Network Controllers (NNC) are widely used in controlling poorlydefined nonlinear and uncertain systems. NNCcourses are now being offered by several universities at the bachelor0s and master's degree levels as a result of NNC's successful applications in these fields. However, the training of an NNC driver circuit in a laboratory environment is a time-consuming and expensive task. In this study, an NNC training set of the DC converter-fed Permanent Magnet Direct Current (PMDC) motor, which is part of the electrical machinery courses, was prepared. The set has a flexible structure and a graphical interface. Thanks to this set, it has become possible to change the PMDC motor and controller parameters, and monitor the system's reaction under various operational conditions in graphics. This training set can also guarantee effective learning and comprehension of Artificial Neural Networks (ANN). © 2012 TEMPUS Publications. Source


In this study, boronizing and/or shot peening surface treatments were applied individually or in combination to the P/M steel specimens. The composition of specimens was 3% Cu. +. 0.2% C. +. balance Fe%. Tensile strength, hardness values and surface properties of treated specimens were determined. Boronizing. +. shot peening surface treatment was found to be the most convenient surface treatment for P/M steel materials based on test results. However, it is important to avoid high peening intensities for shot peening of boronized surfaces because shot peening deteriorates the boronized surface of P/M steel specimens. As a result, surface hardness values such as 1800-2500 HV were achieved after boronizing, the difference between the matrix materials with a hardness of 200 HV was quite high. © 2010 Elsevier B.V. Source


Ilcik J.,Czech Technical University | Arora V.,SDU | Dolejs J.,Czech Technical University
IOP Conference Series: Materials Science and Engineering | Year: 2015

The paper focuses on the updating of the finite element models of the newly developed façade scaffold anchor in the light of the experimental results. The experiments (force-displacement curves) have been carried out on the anchor. The façade scaffold anchor overcomes the problems arising in the process of joining them to the façades through the thermal insulation layers. Using the current methods, the wind load cannot be effectively transferred into the façade and scaffolding stability is decreased. Experimental results are presented and the finite element models of the anchor are developed using non-linear beam and solid elements. It has been observed that the predictions of finite element models that is force-displacement curve do not match with the experiment results. Subsequently, the finite element models of the developed anchor have been updated in the light of experimental results by using the parameter-based finite element model updating method. In case of an anchor, modelling of stiffness of the joints and values of the materials are expected to be dominant sources of inaccuracy in the FE model, assuming that the correct geometric parameters are known. After updating joint stiffness of the anchor joints and material properties, the finite element predictions match with experimental results. The outcomes show that there is a good correlation between the updated finite element models and the experimental data. The accuracy of the updated finite element models is demonstrated by overlaying force-displacement curves with the curve from the experiment, it can be concluded that the updated finite element models of the anchor accurately represent reality. © Published under licence by IOP Publishing Ltd. Source


Kilincarslan S.,SDU
Acta Physica Polonica A | Year: 2015

For the adequate shielding of the radiological equipment using X and gamma rays, special materials with high attenuation properties are needed. This objective may be achieved by the use of concrete. Concrete engineers and technologists must take the role of aggregates more seriously, since there are increasing demands of modern concrete mixtures in terms of technological properties and greater economy. Heavyweight concrete contains aggregates that are natural or synthetic. In this study, metal industry waste products such as iron filings and rebar pieces were used to produce heavy concrete. Physical, mechanical and radiation shielding properties of the obtained concrete with barite, aggregates and artificial aggregates were studied. According to test results, the concrete produced with artificial aggregates can provide the desired physical properties. Radiation shielding coefficient was found to be proportional to the density of concrete. Source

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