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Metropolitan Government of Nashville-Davidson (balance), TN, United States

Dittman E.,Purdue University | Adams D.E.,Vanderbuilt University
Nonlinear Dynamics | Year: 2015

Prior work on a disbonded aluminum honeycomb panel showed evidence of a quadratic stiffness nonlinearity, as well as the presence of an unknown cubic nonlinearity. Approximations to higher order nonlinear single degree of freedom (SDOF) models were solved using the method of multiple scales. These approximations were then used to fit displacement data from a sinusoidal excitation test and determine the coefficients of the model as a function of damage size. Confirmation of the quadratic stiffness nonlinearity was achieved through examination of force restoration curves excited at one-half the primary resonance in conjunction with coefficient fitting of the test data to the model. The data were fit against the higher order models to determine whether the cubic nonlinearity could be stiffness or damping related. The coefficient fitting shows that the cubic nonlinearity is a stiffness nonlinearity. This confirmed what was seen in the force restoration curves when the system was excited at one-third the primary resonance. The ability to match the vibratory behavior of the damage to a SDOF model shows that the use of single frequency excitation at lower frequencies can isolate the nonlinear behavior of the damaged area and identify what damage mechanisms may be involved. © 2015, Springer Science+Business Media Dordrecht.

Shi J.,Mississippi State University | Amgai R.,Mississippi State University | Abdelwahed S.,Mississippi State University | Dubey A.,Vanderbuilt University | And 3 more authors.
2013 IEEE Electric Ship Technologies Symposium, ESTS 2013 | Year: 2013

This paper proposes a novel modeling and simulation environment for ship design based on the principles of Model Integrated Computing (MIC). The proposed approach facilitates the design and analysis of shipboard power systems and similar systems that integrate components from different fields of expertise. The conventional simulation platforms such as Matlab®, Simulink®, PSCAD® and VTB® require the designers to have explicit knowledge of the syntactic and semantic information of the desired domain within the tools. This constraint, however, severely slows down the design and analysis process, and causes cross-domain or cross-platform operations remain error prone and expensive. Our approach focuses on the development of a modeling environment that provides generic support for a variety of application across different domains by capturing modeling concepts, composition principles and operation constraints. For the preliminary demonstration of the modeling concept, in this paper we limit the scope of design to cross-platform implementations of the proposed environment by developing an application model of a simplified shipboard power system and using Matlab engine and VTB solver separately to evaluate the performance with different respects. In the case studies a fault scenario is pre-specified and tested on the system model. The corresponding time domain bus voltage magnitude and angle profiles are generated via invoking external solver, displayed to users and then saved for future analysis. © 2013 IEEE.

Leaver-Fay A.,University of North Carolina at Chapel Hill | Tyka M.,University of Washington | Lewis S.M.,University of North Carolina at Chapel Hill | Lange O.F.,University of Washington | And 28 more authors.
Methods in Enzymology | Year: 2011

We have recently completed a full rearchitecturing of the Rosetta molecular modeling program, generalizing and expanding its existing functionality. The new architecture enables the rapid prototyping of novel protocols by providing easy-to-use interfaces to powerful tools for molecular modeling. The source code of this rearchitecturing has been released as Rosetta3 and is freely available for academic use. At the time of its release, it contained 470,000 lines of code. Counting currently unpublished protocols at the time of this writing, the source includes 1,285,000 lines. Its rapid growth is a testament to its ease of use. This chapter describes the requirements for our new architecture, justifies the design decisions, sketches out central classes, and highlights a few of the common tasks that the new software can perform. © 2011 Elsevier Inc.

Hofmann S.,Helmholtz Center for Heavy Ion Research | Hofmann S.,Goethe University Frankfurt | Heinz S.,Helmholtz Center for Heavy Ion Research | Mann R.,Helmholtz Center for Heavy Ion Research | And 37 more authors.
European Physical Journal A | Year: 2016

The reaction 54Cr + 248Cm was investigated at the velocity filter SHIP at GSI, Darmstadt, with the intention to study production and decay properties of isotopes of element 120. Three correlated signals were measured, which occurred within a period of 279ms. The heights of the signals correspond with the expectations for a decay sequence starting with an isotope of element 120. However, a complete decay chain cannot be established, since a signal from the implantation of the evaporation residue cannot be identified unambiguously. Measured properties of the event chain are discussed in detail. The result is compared with theoretical predictions. Previously measured decay properties of even element super-heavy nuclei were compiled in order to find arguments for an assignment from the systematics of experimental data. In the course of this review, a few tentatively assigned data could be corrected. New interpretations are given for results which could not be assigned definitely in previous studies. The discussion revealed that the cross-section for production of element 120 could be high enough so that a successful experiment seems possible with presently available techniques. However, a continuation of the experiment at SHIP for a necessary confirmation of the results obtained in a relatively short irradiation of five weeks is not possible at GSI presently. Therefore, we decided to publish the results of the measurement and of the review as they exist now. In the summary and outlook section we also present concepts for the continuation of research in the field of super-heavy nuclei. © 2016, SIF, Springer-Verlag Berlin Heidelberg.

Thompson-Spires N.D.,Vanderbuilt University
American Review of Canadian Studies | Year: 2011

Canadian televisual exports make up at least 30 percent of the original content on US cable television. And from many angles, Canadian youth-television series look more diverse, more positive, and more attentive to interracial and interethnic issues than do similar US series. This article explores Canadian representations of interracial relationships and situates them within readings of Canada's official multicultural policy. It argues that much of this surface-level positivism about race reveals unconscious anxieties that ultimately manifest in drastic ways of treating diversity or multicultural subjects. © 2011 ACSUS.

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