124 research outputs found

    The phase free, longitudinal, magnetic component of vacuum electromagnetism

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    A charge qq moving in a reference laboratory system with constant velocity {\bf V} in the XX-axis produces in the ZZ-axis a longitudinal, phase free, vacuum magnetic field which is identified as the radiated B(3){\bf B}^{(3)} field of Evans, Vigier and others.Comment: ReVTeX file, 7pp., no figure

    The influence of thermal cycles on the microstructure of grade 92 steel

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    The microstructure in the heat-affected zone (HAZ) of welds made from the 9 wt pct chromium martensitic Grade 92 steel is complex and has not yet been completely understood. There is a lack of systematic microstructural investigations to define the different regions of the microstructure across the HAZ of Grade 92 steel welds as a function of the welding process. In this study, the microstructure in the HAZ of an as-fabricated single-pass bead-on-plate weld on a parent metal of Grade 92 steel was systematically investigated by using an extensive range of electron and ion-microscopy-based techniques. A dilatometer was used to apply controlled thermal cycles to simulate the microstructures in the different regions of the HAZ. A wide range of microstructural properties in the simulated materials were then characterized and compared with the experimental observations from the weld HAZ. It was found that the microstructure in the HAZ of a single-pass Grade 92 steel weld can be categorized as a function of a decreasing peak temperature reached as (1) the completely transformed (CT) region, in which the original matrix is completely reaustenitized with complete dissolution of the pre-existing secondary precipitate particles; (2) the partially transformed (PT) region, where the original matrix is partially reaustenitized along with a partial dissolution of the secondary precipitate particles from the original matrix; and (3) the overtempered (OT) region, where the pre-xisting precipitate particles coarsen. The PT region is considered to be the susceptible area for damage in the commonly reported HAZ failures in weldments constructed from these types of steels

    On the Existence of Undistorted Progressive Waves (UPWs) of Arbitrary Speeds 0≀v<∞0 \leq v< \infty in Nature

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    We present the theory, the experimental evidence, and fundamental physical consequences concerning the existence of families of undistorted progressive waves (UPWs) of arbitrary speeds 0≀v<∞0\leq v < \infty, which are solutions of the homogeneous wave equation, Maxwell equations, and Dirac and Weyl equations.Comment: 77 pages, Latex article, with figures. Includes corrections to the published versio

    Detecting the Collapse of Cooperation in Evolving Networks

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    The sustainability of biological, social, economic and ecological communities is often determined by the outcome of social conflicts between cooperative and selfish individuals (cheaters). Cheaters avoid the cost of contributing to the community and can occasionally spread in the population leading to the complete collapse of cooperation. Although such collapse often unfolds unexpectedly, it is unclear whether one can detect the risk of cheater’s invasions and loss of cooperation in an evolving community. Here, we combine dynamical networks and evolutionary game theory to study the abrupt loss of cooperation with tools for studying critical transitions. We estimate the risk of cooperation collapse following the introduction of a single cheater under gradually changing conditions. We observe an increase in the average time it takes for cheaters to be eliminated from the community as the risk of collapse increases. We argue that such slow system response resembles slowing down in recovery rates prior to a critical transition. In addition, we show how changes in community structure reflect the risk of cooperation collapse. We find that these changes strongly depend on the mechanism that governs how cheaters evolve in the community. Our results highlight novel directions for detecting abrupt transitions in evolving networks
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