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Structural Control (structural + control)
Selected AbstractsStructural Control of Crystal Nuclei by an Eggshell Protein,ANGEWANDTE CHEMIE, Issue 30 2010Colin Nach Metadynamiksimulationen induziert das Eierschalenprotein Ovocleidin-17 die Umwandlung von amorphen Calciumcarbonat-Nanopartikeln in Calcitkristalle. Wiederholte spontane Kristallisationen und Amorphisierungen wurden simuliert; daraus ließ sich ein Katalysezyklus ableiten, der die Rolle von Ovocleidin-17 zu Beginn der Eierschalenbildung erklärt (im Bild ist eine Zwischenstufe dieses Zyklus gezeigt). [source] Java-powered virtual laboratories for earthquake engineering educationCOMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 3 2005Y. Gao Abstract This paper presents a series of Java-Powered Virtual Laboratories (VLs), which have been developed to provide a means for on-line interactive experiments for undergraduate and graduate education. These VLs intend to provide a conceptual understanding of a wide range of topics related to earthquake engineering, including structural control using the tuned mass damper (TMD) and the hybrid mass damper (HMD), linear and nonlinear base isolation system, and nonlinear structural dynamic analysis of multi-story buildings. A total of five VLs are currently available on-line at: http://cee.uiuc.edu/sstl/java and have been incorporated as a reference implementation of educational modules in the NEESgrid software (http://www.neesgrid.org/). © 2005 Wiley Periodicals, Inc. Comput Appl Eng Educ 13: 200,212, 2005; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20050 [source] Experimental verification of a wireless sensing and control system for structural control using MR dampersEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 10 2007Chin-Hsiung Loh Abstract The performance aspects of a wireless ,active' sensor, including the reliability of the wireless communication channel for real-time data delivery and its application to feedback structural control, are explored in this study. First, the control of magnetorheological (MR) dampers using wireless sensors is examined. Second, the application of the MR-damper to actively control a half-scale three-storey steel building excited at its base by shaking table is studied using a wireless control system assembled from wireless active sensors. With an MR damper installed on each floor (three dampers total), structural responses during seismic excitation are measured by the system's wireless active sensors and wirelessly communicated to each other; upon receipt of response data, the wireless sensor interfaced to each MR damper calculates a desired control action using an LQG controller implemented in the wireless sensor's computational core. In this system, the wireless active sensor is responsible for the reception of response data, determination of optimal control forces, and the issuing of command signals to the MR damper. Various control solutions are formulated in this study and embedded in the wireless control system including centralized and decentralized control algorithms. Copyright © 2007 John Wiley & Sons, Ltd. [source] Landscape metrics indicate differences in patterns and dominant controls of ribbon forests in the Rocky Mountains, USAAPPLIED VEGETATION SCIENCE, Issue 2 2009Matthew F. Bekker Abstract Question: Do landscape metrics reflect differences in dominant factors controlling ribbon forest patterns among sites? Location: West Flattop Mountain, Glacier National Park, Montana (Flattop); Medicine Bow Mountains, Wyoming (Medicine Bow); Park Range, Colorado (Park Range). Methods: High-resolution aerial photography was used to delineate ribbon forest patches, and to calculate landscape metrics to distinguish between long, narrow, regular patterns expected from strong microtopographic control, and smaller, more compact, and variable patterns expected from wind-snowdrift interactions. Results: All but two metrics were significantly different (P<0.05) among the three sites. The rank and magnitude of differences indicated that ribbons at Flattop and Park Range are more similar to each other than to those at Medicine Bow. Flattop ribbons were also more elongated, narrower and less variable than those at Park Range, suggesting differences in the type and strength of structural control. Previous research showed that Flattop ribbons occupy regular lithologic ridges, while our observations of ribbons and analysis of geologic maps suggests weaker and less consistent microtopographic control at Park Range, and dominant wind-snowdrift interactions with little to no microtopographic influence at Medicine Bow. Conclusions: Landscape metrics indicate differences in pattern among sites that reflect differences in dominant factors influencing ribbon forest development and maintenance. Explanations of ribbon forest dynamics are site-specific and are more complex than is currently recognized. The sites vary in the level of endogenous versus exogenous control of ribbon patterns, and consequently in the sensitivity of this phenomenon to climate. [source] Investigating the surface process response to fault interaction and linkage using a numerical modelling approachBASIN RESEARCH, Issue 3 2006P.A. Cowie ABSTRACT In order to better understand the evolution of rift-related topography and sedimentation, we present the results of a numerical modelling study in which elevation changes generated by extensional fault propagation, interaction and linkage are used to drive a landscape evolution model. Drainage network development, landsliding and sediment accumulation in response to faulting are calculated using CASCADE, a numerical model developed by Braun and Sambridge, and the results are compared with field examples. We first show theoretically how the ,fluvial length scale', Lf, in the fluvial incision algorithm can be related to the erodibility of the substrate and can be varied to mimic a range of river behaviour between detachment-limited (DL) and transport-limited (TL) end-member models for river incision. We also present new hydraulic geometry data from an extensional setting which show that channel width does not scale with drainage area where a channel incises through an area of active footwall uplift. We include this information in the coupled model, initially for a single value of Lf, and use it to demonstrate how fault interaction controls the location of the main drainage divide and thus the size of the footwall catchments that develop along an evolving basin-bounding normal fault. We show how erosion by landsliding and fluvial incision varies as the footwall area grows and quantify the volume, source area, and timing of sediment input to the hanging-wall basin through time. We also demonstrate how fault growth imposes a geometrical control on the scaling of river discharge with downstream distance within the footwall catchments, thus influencing the incision rate of rivers that drain into the hanging-wall basin. Whether these rivers continue to flow into the basin after the basin-bounding fault becomes fully linked strongly depends on the value of Lf. We show that such rivers are more likely to maintain their course if they are close to the TL end member (small Lf); as a river becomes progressively more under supplied, i.e. the DL end member (large Lf), it is more likely to be deflected or dammed by the growing fault. These model results are compared quantitatively with real drainage networks from mainland Greece, the Italian Apennines and eastern California. Finally, we infer the calibre of sediments entering the hanging-wall basin by integrating measurements of erosion rate across the growing footwall with the variation in surface processes in space and time. Combining this information with the observed structural control of sediment entry points into individual hanging-wall depocentres we develop a greater understanding of facies changes associated with the rift-initiation to rift-climax transition previously recognised in syn-rift stratigraphy. [source] |