7,997 research outputs found

    Synchrotron Studies of Quantum Emergence in Non-Low Dimensional Materials Final Report

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    This document is the final report of research performed under U.S. DOE Award Number DE-FG02-07ER46379, entitled Synchrotron Studies of Quantum Emergence in Non-Low Dimensional Materials. It covers the full period of the award, from June 1, 2007 through May 31, 2011

    Complexity, Collective Effects and Modelling of Ecosystems: formation, function and stability

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    We discuss the relevance of studying ecology within the framework of Complexity Science from a statistical mechanics approach. Ecology is concerned with understanding how systems level properties emerge out of the multitude of interactions amongst large numbers of components, leading to ecosystems that possess the prototypical characteristics of complex systems. We argue that statistical mechanics is at present the best methodology available to obtain a quantitative description of complex systems, and that ecology is in urgent need of ``integrative'' approaches that are quantitative and non-stationary. We describe examples where combining statistical mechanics and ecology has led to improved ecological modelling and, at the same time, broadened the scope of statistical mechanics.Comment: 11 pages and 1 figur

    Thyroid neoplasia

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    This issue of eMedRef provides information to clinicians on the pathophysiology, diagnosis, and therapeutics of thyroid neoplasia

    Cedar apple rust (1996)

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    In Missouri, cedar apple rust can be a destructive apple disease if you don't use adequate controls. It also attacks red cedars, as the name implies, causing unsightly galls, but damage is usually minimal. Understanding of the disease cycle of this rust fungus is necessary for proper identification and control.Revised 2/96/5M

    Water-propellant resistojets for man-tended platforms

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    The selection of a propulsion system for a man-tended platform has been influenced by the planned use of resistojets for drag make-up on the manned space station. For that application a resistojet has been designed that is capable of operation with a wide variety of propellants, including water. The reasons for the selection of water as the propellant and the performance of water as a propellant are discussed. The man-tended platform and its mission requirements are described

    An experimental comparison of several current viscoplastic constitutive models at elevated temperature

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    Four current viscoplastic models are compared experimentally for Inconel 718 at 593 C. This material system responds with apparent negative strain rate sensitivity, undergoes cyclic work softening, and is susceptible to low cycle fatigue. A series of tests were performed to create a data base from which to evaluate material constants. A method to evaluate the constants is developed which draws on common assumptions for this type of material, recent advances by other researchers, and iterative techniques. A complex history test, not used in calculating the constants, is then used to compare the predictive capabilities of the models. The combination of exponentially based inelastic strain rate equations and dynamic recovery is shown to model this material system with the greatest success. The method of constant calculation developed was successfully applied to the complex material response encountered. Backstress measuring tests were found to be invaluable and to warrant further development

    An automated procedure for material parameter evaluation for viscoplastic constitutive models

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    An automated procedure is presented for evaluating the material parameters in Walker's exponential viscoplastic constitutive model for metals at elevated temperature. Both physical and numerical approximations are utilized to compute the constants for Inconel 718 at 1100 F. When intermediate results are carefully scrutinized and engineering judgement applied, parameters may be computed which yield stress output histories that are in agreement with experimental results. A qualitative assessment of the theta-plot method for predicting the limiting value of stress is also presented. The procedure may also be used as a basis to develop evaluation schemes for other viscoplastic constitutive theories of this type

    A Cooperative Strategy for 21st Century Seapower

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    A Cooperative Strategy for 21st Century Seapower” represents an historical first. Never before have the maritime forces of the United States—the Navy, Marine Corps, and Coast Guard—come together to create a unified maritime strategy. This strategy stresses an approach that integrates seapower with other elements of national power, as well as those of our friends and allies. It describes how seapower will be applied around the world to protect our way of life, as we join with other like-minded nations to protect and sustain the global, inter-connected system through which we prosper
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