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  • Author or Editor: Y. Şahin x
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Abstract

The army and the people use many types of vehicles for industrial applications and military applications. This paper is proposed a construction of a prototype active vehicle suspension system for a one-wheel car model by using a modified Linear Quadric Regulator (LQR). The experimental system is approximately described by non-linear system with two degrees of freedom subject to excitation from profile different road disturbance profile. The active control at the suspension location is designed by using feedback constant gain controller structure. Furthermore, the experimental results show that the active suspension system with LQR more improves the control performance than standard PID controller. On the other hand, the results improved that the modified LQR has superior performance for controlling suspension systems in real time.

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Authors: A. Küçükönder, Y. Sąhín and E. Büyükkasap

Abstract  

The K/K X-ray intensity ratios were measured for pure Cr, Mn, Co and Cu belonging to the 3 d shell as well as in their compounds, to look for the influence of the chemical environment on the fluorescence yield ratios. The vacancies in the K shell created by 59.5 keV -rays from an241Am source and the X-rays were measured using a Ge(Li) detector. A steady increase of the K/K intensity ratio was observed with increasing oxidation. The present results agree with previously published experimental data.

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Abstract  

The K/K intensity ratios for Ti, V and Cr in halogen (F and Cl) compounds were investigated. Measurements were carried out at ten different energies in the 5.5-12.1 keV interval by using the secondary excitation method. K X-rays emitted by the samples were counted by a Si(Li) detector with a resolution of 160 eV at 5.9 keV. It was observed that the measured values are getting closer to the theoretical values with increasing excitation energy. Values obtained were compared with the theoretical ones for pure elements.

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Abstract  

Chemical shifts and full widths at half maximum intensity (FWHM) of Kα and Kβ1,3 X-ray emission lines and differences of full widths at half maximum intensity (ΔFHWM) using metallic element as reference for these emission lines were measured for oxygen compounds of elements in the range 22≤Z≤29 with a Wavelength-Dispersive X-Ray Fluorescence Spectrometer (WDXRF). It was also found larger chemical shifts and FWHM for Kβ1,3 lines than those of Kα ones. It should be noted that the magnitude of the chemical shifts increases with increasing number of ligand atom.

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Abstract  

The differential cross sections of the emission of M-shell fluorescence X-rays from Tl and Pb have been measured by 5.96 keV photons at seven angles ranging from 50° to 110°. The differential cross section is found to decrease with the increasing emission angle, showing an anisotropic spatial distribution of M-shell fluorescence X-rays. Furthermore, M-shell fluorescence cross sections and the average fluorescence yields were measured for Pt, Au, Hg, Tl, Pb, Bi, Th, and U at an excitation energy of 5.96 keV using a Si(Li) detector. The experimental results of the total M X-ray fluorescence cross sections and M-shell fluorescence yields were compared with the theoretical values.

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Abstract  

Two analytical shape functions representing the shapes of - and characteristic X-ray photopeak sides obtained with a Ge(Li) detector are described. The photopeak centroid is accurately determined by using these functions. Energy dependence of photopeak tailing at the lower energy side of the photopeaks are obtained by the least-squares fitting method. The present method can be used for the analysis of partly overlapped photopeaks, one side of which is well resolved, with a sufficient accuracy.

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Abstract  

Sea-bed sediments from Eastern Black Sea have been analyzed for their Fe, Ba and Sr contents using the methods of standard addition and energy dispersive X-ray fluorescence (EDXRF). Samples were prepared from powder sifted by a 200 mesh sieve. An annular 100 mCi241Am radioactive source emitting 59.543 keV photons was used for excitation and a Ge(Li) detector, which has a 190 eV FWHM for 5.9 keV photons was used for intensity measurements. 2048 channels of the MCA are employed for 20 or 30 min. Dried and ground sea-bed sediments are found to contain 2.95–7.50% Fe, 0.032–0.268% Ba and about 73–273 ppm Sr. These results agree with those obtained via atomic absorption methods.

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Abstract  

La and Lb X-ray fluorescence cross sections in Er, Ta, W and Au at excitation energies of 16.896, 22.581, 25.770, 32.890, 38.184, 43.949, 50.214 and 59.5 keV were investigated. Measurements were made using a low energy Si(Li) detector coupled to a model 4096 computerized multi-channel analyser. The experimental results were compared with the theoretically calculated values of L X-rays fluorescence cross sections and other experimental results. Good agreement was observed between experimental and theoretical values.

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Authors: Ö. Sögüt, E. Baydaş, E. Büyükkasap, Y. Şahin and A. Küçükönder

Abstract  

Chemical effects on the average L shell fluorescence yields (vL) for Ba, La and Ce compounds were investigated. Samples were excited by gamma-rays with 59.5 keV energy photons from a 241Am radioisotope source. L X-rays emitted by samples were counted by a Si(Li) detector with a resolution 155 eV at 5.9 keV. Chemical effects on the average L shell fluorescence yield (v L) for Ba, La and Ce compounds were observed. The values are compared with theoretical and experimental ones for the pure elements.

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Authors: E. Büyükkasap, A. Küçükönder, Y. Şahin and H. Erdoğan

Abstract  

K/K intensity ratios for Cr, Mn, Fe, Cs and Ba have been measured following radioactive decay and photon excitation. A Ge(Li) detector coupled to an ND66B analyzer was used in the measurements. The K/K intensity ratio is affected by the mode of excitation. This effect has a significant influence on K/K intensity ratios of 3d shell elements (Cr, Mn, Fe). However, the effect was found smaller for Cs and Ba.

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