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Basic Elements (basic + element)
Selected AbstractsMetamaterials: How Far Are We from Making Metamaterials by Self-Organization?ADVANCED FUNCTIONAL MATERIALS, Issue 7 2010The Microstructure of Highly Anisotropic Particles with an SRR-Like Geometry (Adv. Funct. As part of ongoing efforts to create metamaterials by engineered self-organization using solidification of eutectics, D. A. Pawlak et al. report on page 1116 the fabrication of a fractal material with split-tubes mimicking (in cross section) the famous split-ring resonators (SRRs). The latter, when made of metal, are the basic element of a structure showing negative refractive index. This article shows that metallo-dielectric structures can be fabricated. The method employed has high potential for manufacturing materials with various functionalities. [source] Towards analog implementations of PWL two-dimensional non-linear functionsINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 2 2005Marco Storace Abstract This paper deals with the circuit implementation of non-linear algebraic bivariate functions. The synthesis procedure is based on a piecewise-linear approximation technique and on a corresponding circuit architecture, whose basic element is a circuit block with the input/output function y(x) = max(0; x). Some known CMOS circuit structures that can be used to obtain such a block are considered, and their main advantages and drawbacks are pointed out. The static and dynamic features of both the single circuit block and the overall architecture for two-dimensional PWL functions are illustrated by way of examples. Copyright © 2005 John Wiley & Sons, Ltd. [source] Sketching and Composing Widgets for 3D ManipulationCOMPUTER GRAPHICS FORUM, Issue 2 2008Ryan Schmidt Abstract We present an interface for 3D object manipulation in which standard transformation tools are replaced with transient 3D widgets invoked by sketching context-dependent strokes. The widgets are automatically aligned to axes and planes determined by the user's stroke. Sketched pivot-points further expand the interaction vocabulary. Using gestural commands, these basic elements can be assembled into dynamic, user-constructed 3D transformation systems. We supplement precise widget interaction with techniques for coarse object positioning and snapping. Our approach, which is implemented within a broader sketch-based modeling system, also integrates an underlying "widget history" to enable the fluid transfer of widgets between objects. An evaluation indicates that users familiar with 3D manipulation concepts can be taught how to efficiently use our system in under an hour. [source] Highly Porous Nano- and Microstructured Films Loaded with Bioactive Agents for Biomedical Applications: Structure,Release Profile EffectsADVANCED ENGINEERING MATERIALS, Issue 8 2009Adi Rachelson The current study focuses on the nanostructuring of our new drug-eluting porous films and its effect on the drug release profile of both hydrophilic and hydrophobic drugs. Nanostructuring was obtained using both the dispersion and the condensation methods of emulsion processing. These new highly porous nanostructured films can be used as basic elements of various drug-eluting medical devices. [source] Bond rolling resistance and its effect on yielding of bonded granulates by DEM analysesINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 8 2006M. J. Jiang Abstract A discrete element modelling of bonded granulates and investigation on the bond effect on their behaviour are very important to geomechanics. This paper presents a two-dimensional (2-D) discrete element theory for bonded granulates with bond rolling resistance and provides a numerical investigation into the effect of bond rolling resistance on the yielding of bonded granulates. The model consists of mechanical contact models and equations governing the motion of bonded particles. The key point of the theory is that the assumption in the original bond contact model previously proposed by the authors (55th CSCE-ASCE Conference, Hamilton, Ont., Canada, 2002; 313,320; J. Eng. Mech. (ASCE) 2005; 131(11):1209,1213) that bonded particles are in contact at discrete points, is here replaced by a more reliable assumption that bonded particles are in contact over a width. By making the idealization that the bond contact width is continuously distributed with the normal/tangential basic elements (BE) (each BE is composed of spring, dashpot, bond, slider or divider), we establish a bond rolling contact model together with bond normal/tangential contact models, and also relate the governing equations to local equilibrium. Only one physical parameter , needs to be introduced in the theory in comparison to the original bond discrete element model. The model has been implemented into a 2-D distinct element method code, NS2D. Using the NS2D, a total of 86 1-D, constant stress ratio, and biaxial compressions tests have been carried out on the bonded granular samples of different densities, bonding strengths and rolling resistances. The numerical results show that: (i) the new theory predicts a larger internal friction angle, a larger yielding stress, more brittle behaviour and larger final broken contact ratio than the original bond model; (ii) the yielding stress increases nonlinearly with the increasing value of ,, and (iii) the first-yield curve (initiation of bond breakage), which define a zone of none bond breakage and which shape and size are affected by the material density, is amplified by the bond rolling resistance in analogous to that predicted by the original bond model. Copyright © 2006 John Wiley & Sons, Ltd. [source] Mixture-based adaptive probabilistic controlINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 2 2003Miroslav Kárný Abstract Quasi-Bayes algorithm, combined with stabilized forgetting, provides a tool for efficient recursive estimation of dynamic probabilistic mixture models. They can be interpreted either as models of closed-loop with switching modes and controllers or as a universal approximation of a wide class of non-linear control loops. Fully probabilistic control design extended to mixture models makes basis of a powerful class of adaptive controllers based on the receding-horizon certainty equivalence strategy. Paper summarizes the basic elements mentioned above, classifies possible types of control problems and provides solution of the key one referred to as ,simultaneous' design. Results are illustrated on mixtures with components formed by normal auto-regression models with external variable (ARX). Copyright © 2003 John Wiley & Sons, Ltd. [source] Ecologically Functional Floodplains: Connectivity, Flow Regime, and Scale,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 2 2010Jeffrey J. Opperman Opperman, Jeffrey J., Ryan Luster, Bruce A. McKenney, Michael Roberts, and Amanda Wrona Meadows, 2010. Ecologically Functional Floodplains: Connectivity, Flow Regime, and Scale. Journal of the American Water Resources Association (JAWRA) 46(2):211-226. DOI: 10.1111/j.1752-1688.2010.00426.x Abstract:, This paper proposes a conceptual model that captures key attributes of ecologically functional floodplains, encompassing three basic elements: (1) hydrologic connectivity between the river and the floodplain, (2) a variable hydrograph that reflects seasonal precipitation patterns and retains a range of both high and low flow events, and (3) sufficient spatial scale to encompass dynamic processes and for floodplain benefits to accrue to a meaningful level. Although floodplains support high levels of biodiversity and some of the most productive ecosystems on Earth, they are also among the most converted and threatened ecosystems and therefore have recently become the focus of conservation and restoration programs across the United States and globally. These efforts seek to conserve or restore complex, highly variable ecosystems and often must simultaneously address both land and water management. Thus, such efforts must overcome considerable scientific, technical, and socioeconomic challenges. In addition to proposing a scientific conceptual model, this paper also includes three case studies that illustrate methods for addressing these technical and socioeconomic challenges within projects that seek to promote ecologically functional floodplains through river-floodplain reconnection and/or restoration of key components of hydrological variability. [source] Advances in laser technology for isolated attosecond pulse generationLASER PHYSICS LETTERS, Issue 4 2009C. Vozzi Abstract In this review we report on recent advances in laser technology, which have contributed to the fast development of attosecond science. In particular we will concentrate on two experimental methods for the generation of high-peak-power, fewoptical-cycle laser pulses with controlled electric field, which are crucial for the generation of isolated attosecond pulses. The first method is the hollow-fiber compression technique, introduced in 1996 and now routinely used in several laboratories. So far, isolated attosecond pulses have been generated by using few-cycle pulses produced by such compression technique, in combination with active stabilization of the carrier-envelope phase. More recently, few-cycle pulses tunable in the infrared region have been generated by optical parametric amplification with passive stabilization of the carrier-envelope phase. Such parametric sources represent excellent drivers for the generation of harmonic radiation with an extended cutoff, and offer the possibility to extend attosecond science towards the soft-X rays region. Finally, we will briefly discuss the basic elements of attosecond metrology. (© 2009 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source] Mega thinking and planning: An introduction to defining and delivering individual and organizational successPERFORMANCE IMPROVEMENT QUARTERLY, Issue 2 2009Roger Kaufman All organizations are means to societal ends, and thus Mega thinking and planning starts with a primary focus on adding value for all stakeholders, including our shared society. It is pragmatic, realistic, practical, and ethical. Defining and achieving continual organizational success is possible. It relies on three basic elements: (1) a societal value-added "frame of mind" (your perspective and commitment about your organization, people, and our shared world), (2) shared determination and agreement on where to head and why (everyone who can or might be affected by the shared objectives must agree on purposes and results criteria), and (3) pragmatic and basic tools. The article presents the basic concepts for thinking and planning Mega to define and deliver value to internal and external partners, defining and delivering individual and organizational success. [source] Institutions and Development: A Conceptual ReanalysisPOPULATION AND DEVELOPMENT REVIEW, Issue 2 2006Alejandro Portes This essay reviews the concept of "institutions" as used in the recent economic literatures on firms and national development and notes its limitations. An alternative framework is proposed that draws on classic and contemporary sociological theory to position the concept of institutions in relation to other basic elements of culture and social structure. The framework is used to analyze (1) the failure of attempts to transplant institutions of developed countries into the global South and (2) the dynamics of massive privatization in Mexico. The bearing of this framework on current institutional theories of social change is examined, leading to the identification of sources of change at different levels of causal significance and scope. This modified theory of change is applied to the longstanding demographic debates on historical and institutional determinants of fertility transitions. The bearing of the proposed "thick institutionalist" framework on social theory and future development policies is discussed. [source] Source Material: "Does This Constitute a Press Conference?"PRESIDENTIAL STUDIES QUARTERLY, Issue 1 2003Defining, Tabulating Modern Presidential Press Conferences The presidential press conference has demonstrated the way in which both sides have adapted to their own environments. By studying the frequency, format, location, and participants, we can see the ways in which a president responds to reporters'needs for information and the president's own need to present himself and his programs but to do so in an environment where the risk level is manageable. In this article, the author is looking at the variations in the basic elements of the press conference as seen in the modern era conferences of Presidents Lyndon Johnson, Richard Nixon, Gerald Ford, Jimmy Carter, Ronald Reagan, George H. W. Bush, Bill Clinton, and George W. Bush. This piece is restricted to looking at the at the classification of press conferences and exploring their variety as expressed in the number of the locations where they are held and the assortment of participants in addition to the president. [source] More than Writing on a Wall: Evaluating the Role that Codes of Ethics Play in Securing Accountability of Public Sector Decision-MakersAUSTRALIAN JOURNAL OF PUBLIC ADMINISTRATION, Issue 1 2007Niamh Kinchin This article argues that the essential factors of a public service code of ethics can be divided into five categories. These categories or principles are fairness, transparency, responsibility, efficiency and conflict of interest. These principles are identified in this article as being the basic elements of democratic accountability in relation to public sector decision-making. The issues explored are not only the obstacles that the public service decision-maker faces in internalising these principles but, also, the challenges for a pro-active management in fostering such internalisation. [source] Grundlagen des Lebensdauermanagements im KraftwerksbauBETON- UND STAHLBETONBAU, Issue 7 2010Tobias Pfister Dr.-Ing. Allgemeines; Bauwerkserhaltung/Sanierung; Bauwerksüberwachung Abstract Der Begriff des "Lebensdauermanagements" rückt im Kraftwerksbau auch bei der Planung von Neubauten verstärkt in das Blickfeld der Betreiber. Darüber hinaus werden für Bestandsbauwerke unter dem Einfluss von Laufzeitverlängerungen Maßnahmen erforderlich, die die Restlebensdauer zuverlässig bewerten und sicherstellen können. Der vorliegende Beitrag zeichnet die rechtlichen Rahmenbedingungen nach, aus denen sich das Erfordernis eines aktiven Lebensdauermanagements ergibt und stellt die Vorgehensweise und grundlegenden Elemente einer derartigen begleitenden Überwachungsstrategie dar. Fundamentals of Lifetime Management in Power Plants The concept of "lifetime management" moves more and more into the focus of power plant owners, also in the context of new constructions. Additionally, for existing buildings there is a demand for methods, which are able to estimate the remaining lifetime in a reliable way. The present contribution collocates the legal general conditions, which lead to a requirement of an active lifetime management, and presents the procedure and basic elements of such an accompanying inspection strategy. [source] | |||||||||||||||||||