Papers by Keyword: Se

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Authors: Pankaj N. Shrirao, Parvezalam I. Shaikh, Farazuddin Zafaruddin, A.N. Pawar
Abstract: Tests were performed on a single cylinder, four stroke, direct injection, diesel engine whose piston crown, cylinder head and valves were coated with a 0.5 mm thickness of 3Al2O3 .2SiO2 (mullite) (Al2O3= 60%, SiO2= 40%) over a 150 µm thickness of NiCrAlY bond coat. The working conditions for the conventional engine (without coating) and LHR (mullite coated) engine were kept exactly same to ensure a comparison between the two configurations of the engine. This paper is intended to emphasis on emission characteristics of diesel engine with and without mullite coating under identical conditions. Tests were carried out at same operational constraints i.e. air-fuel ratio and engine speed conditions for both conventional engine (without coating) and LHR (mullite coated) engines. The results showed that, there was as much as29.41% and 24.35% decreasing on CO and HC emissions respectively for LHR (mullite coated) engine compared to conventional engine (without coating) at full load. The average decrease in smoke density in the LHR engine compared with the conventional engine was 13.82 % for full engine load. However, there was as much as 20% increasing on NOx emission for LHR engine compared to conventional engine at full load. Also the results revealed that, there was as much as 22% increasing on exhaust gas temperature for LHR engine compared to conventional engine at full engine load.
344
Authors: Monika Jenko, M. Godec, H. Viefhaus, Hans Jürgen Grabke
747
Authors: Z.J. Ding, H.M. Li, X. Sun
Abstract: Topographic imaging of materials by a scanning electron microscope (SEM), using the secondary electrons and backscattered electrons escaped from the surface under a primary electron beam bombardment as image signals, has been a very important technique in application to material sciences and the related fields. In this work we have developed a new parallel Monte Carlo simulation program to calculate SEM images especially for an inhomogeneous sample with a complex structure, which may be constructed with some basic geometrical shapes containing different materials. The ray-tracing arithmetic is employed to obtain the corrected electron flight step length for electrons across the interface of different zones containing distinct elements. We have done simulations for several specimens with artificial structures at the nm level. The results illustrate some new characters of image contrast, demonstrating the applicability of this image simulation technique to the characterization of nano-scale structure.
4161
Authors: Hiroshi Miyazawa, Masafumi Ogata, Keisuke Shinohara, Akira Sugawara, Ikuo Shohji
Abstract: Electrodeposited silver layers obtained from high-cyanide silver plating solution are widely applied for connectors and switches of automobiles. However, few groups have discussed the relationship between the crystal structure of silver layers and their properties. In this study, the effect of the concentration of Se, added as a brightener to high-cyanide silver plating solution, was investigated by XRD and EBSD analysis for electrodeposited silver layers with {200} orientation. By optimizing the concentration of Se in the silver plating solution, the {200} orientation ratio of the silver layer was increased to as high as 94%. Since the diffusion of Cu from the Cu substrate used in this study into the silver layer was inhibited, the silver layer with the high {200} orientation ratio exhibited good electrical contact resistance of the surface of 1.3mΩ after a heating test performed at 200°C for 74h. In addition, the silver layer had good bend formability. The results of XRD analysis confirmed that the recrystallization of the electrodeposited silver layer occurred at room temperature within several hours, thus increasing the {200} orientation ratio of the silver layer.
1458
Authors: R. Hanada, T. Shinozuka, Masato Fujioka
1369
Authors: Gui Shu Xia, Chao Zhou
Abstract: In this paper, electric field shielding effectiveness (SE) of metallic experiment boxwith aperturesilluminated by vertical polarization plane wave has been studied by using modal method of moment technique. Electric field SE has been calculated at three different points on the same plane inside enclosure. The numerical results of the proposed technique are in very good agreement with data available in the literature and experimental results. It is shown that apertures position, aperture number and calculation points have noticeable effect on the electric field SE,four apertures is a better select to improve the shielding ability of an enclosure than one aperture while they have the same area.
4376
Authors: Yuan Li, Ai Hui Liang, Wen Qing Yin, Zhi Liang Jiang
Abstract: In the HCl medium of 0.90 mol/L, Se (IV) was reduced by NaH2PO2 and generated selenium nanoparticles, and there is a resonance Rayleigh scattering (RRS) peak at 588 nm. Under the selected conditions, with the increased of Se (IV) concentration, generated selenium nanoparticles increased, the resonance Rayleigh scattering peak intensity (ΔI588nm) at 588 nm was increased, and the ΔI588nm had good linear relationship to Se (IV) concentration in the range of 0.1-1.5 mg/L, with a linear regression equation of ΔI588nm= 489.9C + 9.0, the detection limit of 12.0 μg/L.
396
Authors: M.R. Hassan, M. Mehrpouya, Sattar Emamian, M.N. Sheikholeslam
Abstract: Self-healing has usually an emphasis on special materials that is metallic materials. When there is a minor damage, almost all biological organisms, even complex ones, have the ability to repair themselves. Recently, a novel field of materials science is constituted by self-healing in organic materials or material systems and it is rapidly expanding. These materials have a particular ability to heal themselves. The initial crack is healed to the point that upon reloading, a new crack is formed next to the original, rather than the original crack reopening. Only simple heating can reverse transformation and cause reinforcement for these cracks. The shape memory alloy wires are activated by heating the system and therefore the healing begins. Due to the heat, the wires relapse to their original shape at the shape change in martensite to austenite transition temperature. The concentration of most of the studies so far has been on polymers and ceramics and the reason is that it includes self-healing in non-metallic materials. Also, they are more convenient than including it in metallic materials. In this review paper the design principles of self-healing materials and their improvement methods are investigated.
87
Authors: Rong Bo Zheng, Xue Lian Guo, Kang Zheng
Abstract: The Se/Te alloys nanorods have been synthesized through spontaneous oxidation of NaHE (E = Se and Te) by dissolved oxygen at room temperature. Phase structures and morphologies of the Se/Te products are investigated by XRD, EDS, SEM, and TEM. The composition of Se/Te alloys could be tuned via simply changing the value of n (n denoted as molar ratio of the starting reagent Se to Te). In order to obtain pure Se/Te alloys nanorods, the value of n should be higher than 3. Otherwise, by-product t-Te would be formed. A possible nucleation and growth mechanism of the Se/Te nanorods was discussed.
680
Authors: Chao Zhou, Ling Tong
Abstract: In this paper, electric field shielding effectiveness (SE) of rectangular enclosure with four apertures illuminated by vertical polarization plane wave has been studied by using modal method of moment technique. Electric field SE of enclosure with four square apertures has been calculated at three different points on the same plane inside enclosure. The numerical results of the proposed technique are in very good agreement with data available in the literature and experimental results. It is shown that apertures’ position and aperture’ number have noticeable effect on the electric field SE.
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