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Different Aspect Ratios (different + aspect_ratio)
Selected AbstractsEarthquake behavior of structures with copper energy dissipatorsEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 3 2004Juan C. De la Llera Abstract The earthquake behavior of structures with supplemental copper dampers is evaluated in this study. The investigation is divided into two parts: (i) an experimental work with seven pairs of hourglass copper dampers of different aspect ratios and side profiles; and (ii) a parametric study of 6-, 12-, and 25-story planar structures with elastic as well as inelastic behavior in the primary structure and copper dampers. The copper used in this study is electrolytic tough pitch (ETP) copper C11000; probably the most commonly used of all coppers; ductile, with a low-yield, and highly resistant to corrosion. Experimental results demonstrate that all copper plates reached stable angular distortions of the order of ,=25%, which implies transverse distortions in the devices larger than 40mm. The behavior of the devices is highly dependent on the aspect ratio of the plate, h/t, and a recommendation is made to use plates in the range 11 h/t,18. Plates beyond this range exhibit either large stress and strain concentrations in the neck of the device or a strong influence of axial deformations in their cyclic behavior. The inelastic earthquake response of structures with such devices shows that drift reduction factors of the order of 30 to 40% can be achieved with reasonably economic designs. It is also shown that the efficiency of these devices depends on the soil conditions and flexibility of the primary structure. Finally, it is concluded that supplemental copper dampers are a good alternative for drift reduction in a wide range of structural layouts, ranging from coupled shear-wall systems to moment-resisting frames, and for impulsive as well as non-impulsive ground motions. Copyright © 2003 John Wiley & Sons, Ltd. [source] The effect of jet array arrangement on the flow characteristics of the outlet hole in short confined channelsHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 1 2008Liu Haiyong Abstract This experimental study is part of the research program related to the aerodynamic characteristics of impingement in a confined channel. Experimental research on better understanding flow structure in confined channel with impingement cooling is rarely found in open literature. The main purposes of this project are (1) gaining greater insight into the structure of the impingement jet flow and flow in the outlet hole; (2) understanding the effect of impingement hole arrangement build up on the flow structure and aerodynamic parameters within holes and channels with different aspect ratios. The test models are two confined channels with three staggered circular jet holes, and a single large size outlet hole placed downstream of the jet plate. The structure parameters of these orifices are different. In this paper, detailed flow field in the outlet hole was measured with a straight five-hole probe, and the discharge coefficient of outlet holes with different aspect ratios was also studied in each channel. Experimental data shows that the jet arrangement has little influence on the flow behavior of the outlet hole when the aspect ratio of the passage was 1, but it played an important role on the discharge coefficient. Distinctively different flow patterns were found in two models with the aspect ratios of 3 and 5, while the variation of the discharge coefficient showed a slight influence on impingement hole arrangement. © 2007 Wiley Periodicals, Inc. Heat Trans Asian Res, 37(1): 20,28, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20188 [source] The Patterning of Sub-500 nm Inorganic Oxide Structures,ADVANCED MATERIALS, Issue 14 2008Meredith J. Hampton Elastomeric perfluoropolyether molds are applied to pattern arrays of sub-500 nm inorganic oxide features. This versatile soft-lithography technique can be used to pattern a wide range of materials; in this work inorganic oxides including TiO2, SnO2, ZnO, ITO, and BaTiO3 are patterned on a variety of substrates with different aspect ratios. An example of TiO2 posts is shown in the figure. [source] Synthesis of ZnO whiskers with different aspect ratios by a facile solution routePHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2008Juan Xie Abstract Monodispersed zinc oxide (ZnO) whiskers with different aspect ratios were successfully prepared via a simple solution route at low temperature. It is found that the diameter and aspect ratio of ZnO whiskers depend critically on the structure and type of ionic surfactant added in the reaction solution. To further understand the effect of the surfactants on the formation process of ZnO whiskers, concentration measurements of Zn(II) remaining in the solution as well as scanning electron microscopy (SEM) and X-ray powder diffraction (XRD) analyses of the solid product have been made at regular intervals throughout the reaction with and without the surfactants. A possible formation process has been reasonably suggested based on these systematic experimental results. It is believed that anion surfactants are capable of slowing down the nucleation and growth rate of ZnO crystallite, which is favorable for the anisotropic growth habit of ZnO crystal to form needle-like whiskers. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||