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This toolkit was developed by the Electronic Media Branch, Division of News and Electronic Media, Office of the Associate Director of Communication at the Centers for Disease Control and Prevention (CDC). It was designed to provid...
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This toolkit was developed by the Electronic Media Branch, Division of News and Electronic Media, Office of the Associate Director of Communication at the Centers for Disease Control and Prevention (CDC). It was designed to provide guidance and to the share lessons learned in more than three years of integrating social media into CDC health communication campaigns, activities and emergency response efforts. In this guide, you will find information to help you get started using social media from developing governance to determining which channels best meet your communication objectives to creating a social media strategy.
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In this contribution we give an overview of some aspects of the derivation of Green dyadics for bianisotropic media. The Green dyadics are the basic solutions for the source problem. We will derive the Green dyadics for homogeneou...
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In this contribution we give an overview of some aspects of the derivation of Green dyadics for bianisotropic media. The Green dyadics are the basic solutions for the source problem. We will derive the Green dyadics for homogeneous media, for layered media and for waveguides. For each of these structures different techniques will be used. For homogeneous media we can sometimes resort to analytical techniques. For layered media a numerical spectral domain technique is proposed based on a recursive algorithm to handle a stack of layers. An eigenmode expansion is used to drive an expression for the Green dyadics in bianisotropic waveguides. We will also pay attention to the singular behavior of the Green dyadic.
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The basics of wave phenomena in waveguides with circulatory cylindrical cross section, which are filled with dispersive materials are studied in this report. The purpose is to apply the recently introduced method, which is suitabl...
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The basics of wave phenomena in waveguides with circulatory cylindrical cross section, which are filled with dispersive materials are studied in this report. The purpose is to apply the recently introduced method, which is suitable to use in different applications of the wave phenomena in dispersive and time varying media, for bounded cases in two dimensions. The perspective of the report includes the application of convenient transformations for waves in dispersive and bounded media. The solution is obtained for both of gradient and non-gradient media. The application of the method is given for a time dependent and frequency varying (TDFV/TVFD) circularly cylindrical waveguide.
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The basics of wave phenomena in waveguides with rectangular cross section which are filled with dispersive materials are studied in this report. The purpose is to apply the recently introduced method, which is suitable to use in d...
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The basics of wave phenomena in waveguides with rectangular cross section which are filled with dispersive materials are studied in this report. The purpose is to apply the recently introduced method, which is suitable to use in different applications of the wave phenomena in dispersive and time varying media, for bounded cases in two-dimension. The perspective of the report includes the application of convenient transformations for waves in dispersive and bounded media. The solution is obtained for both of gradient and non-gradient media. The application of the method is given for a time dependent and frequency varying (TDFV/TVDF) rectangular waveguide.
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Social media garnered much attention from the Arab Spring uprisings where activists took advantage of computer and mobile phone technologies to organize the collective actions of thousands of citizens. The influence and power of s...
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Social media garnered much attention from the Arab Spring uprisings where activists took advantage of computer and mobile phone technologies to organize the collective actions of thousands of citizens. The influence and power of social media are only likely to increase. According to eMarketer (2012), by 2014, over one-fourth of the world s population will be using social media technology. However, military planning has not fully harnessed this powerful tool. In trying to understand how this technology should be utilized by special operations forces (SOF), this thesis examines the role that social media plays in various forms of conflict across the globe. Specifically, this research assesses and identifies what types of social media should be used to support a range of special operations objectives, from strategic influence to disruption, coercions, and regime overthrow. Additionally, a social media assessment methodology is provided that can be used by strategists to evaluate the most appropriate use of social media technology to support special operations.
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The far field displacements in an infinite transversely isotropic elastic medium subjected to an oscillatory concentrated force are derived. The concepts of velocity surface, slowness surface and wave surface are used to describe ...
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The far field displacements in an infinite transversely isotropic elastic medium subjected to an oscillatory concentrated force are derived. The concepts of velocity surface, slowness surface and wave surface are used to describe the geometry of the wave propagation process. It is shown that the decay of the wave amplitudes depends not only on the distance from the source (as in isotropic media) but also depends on the direction of the point of interest from the source. As an example, the displacement field is computed for a laboratory fabricated unidirectional fiberglass epoxy composite. The solution for the displacements is expressed as an amplitude distribution and is presented in polar diagrams. This analysis has potential usefulness in the acoustic emission (AE) and ultrasonic nondestructive evaluation of composite materials. For example, the transient localized disturbances which are generally associated with AE sources can be modeled via this analysis. In which case, knowledge of the displacement field which arrives at a receiving transducer allows inferences regarding the strength and orientation of the source, and consequently perhaps the degree of damage within the composite.
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