Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 41 for “"Cloak"”.
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Investigation of defects on acoustic scattering in cloak by molding process
… was developed in order to replicate the acoustic cloak. The metal was cast into a stretchable PDMS mold, which was cast from micromachined aluminum cloak. For the PDMS mold, the mold release agent, trichlorosilane ([tridecafluoro-1,1,2,2-tetrahydrooctyl] trichlorosilane), was enhanced to imprint …
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Creation of a covert communications network for evasion of surveillance
… such are subject to some degree of interference. Cloak is a textual communication network created to hide the existence of the network itself from an outside observer, such as a repressive government or corrupt corporation. Cloak does not use the public internet, and as such would evade the …
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Study on transformation-based invisibility cloaks
… opportunity for realizing invisibility cloaking. Coordinate transformation theory predicts that by squeezing the space to form a "hole" in it, any object inside the "hole" becomes completely invisible from electromagnetic waves. A metamaterial shell can thus be designed to mimic this …
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Acoustic metamaterial design and applications
… examples these years is the invisible cloak. Such a device is proposed to render the hidden object undetectable under the flow of light or sound, by guiding and controlling the wave path through an engineered space surrounding the object. However, the cloak designed by transformation …
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Advances in Complex Electromagnetic Media
… structures such as the invisibility cloak.</p><p>In this dissertation the tools used in the field of transformation optics will be explored and expanded. Several new designs are discussed, each of which expands upon the ideas that have previously been employed in the field. To begin, …
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Hierarchical Semiconductor, Metal and Hybrid Nanostructures and the Study of their Light-matter Interactions
… metamaterial designed to function as an optical cloak in the visible range. A composite material consisting of an array of silver nanowires (NWs) in a dielectric host has been produced based on the theory of a non-magnetic optical cloak. The required radial array of silver NWs was achieved by …
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Rheumatic endocarditis in children
… To term a condition "rheumatic" is too often to cloak one's ignorance of what the true diagnosis is. In spite of the careful and tedious researches of such men as Church, Triboulet, Still, Poynton, Paine,Singer, etc. our knowledge of what we term "Rheumatism" is still imperfect. The pathology has …
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Design and Experimental Applications of Acoustic Metamaterials
… and we also realize a 2D acoustic ground cloak in air. In addition, we explore the performance of some novel applications (a 2D acoustic black hole and a three-dimensional acoustic cloak) using the currently available acoustic metamaterials. In order to overcome the limitations of our …
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Reduction Of Mutual Coupling In Antenna Technology Using Elliptically Shaped Metasurfaces
… is done first using a graphene monolayer as a cloak to decrease mutual coupling and restore radiation patterns for closely spaced antennas at THz frequencies. The introduction of the graphene monolayer was also extensively studied in regards to the effect on the radiation properties of the …
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God is the Best Guardian: Islamic Talismanic Shirts from the Gunpowder Empires
… khila' (robe of honor) and the khirqa (the Sufi cloak) provide important insights into how garments become the physical markers of bodily interactions. By reinforcing the relationship between textiles and the human body within these systems, it becomes clear that Islamic talismanic shirts amplify …
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A Band of Sisters: Female Detectives, Authority, and Fiction from 1864 to the 1930s
… Similarly, mystery and detective fiction wear a cloak of conservatism to gain closer access to their audience in order to effect change. While several stories and characters re-establish order and the status quo, several others allow for the possibility for the world to remain transgressive, …
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The chronic and acute effects of whole body vibration training
Whole body vibration training (WBVT) has gained a lot of interest for its proposed benefits across a range of populations both active and injured. The purpose of the present thesis was to test the efficacy of WBVT in terms of injury rehabilitation and performance enhancement amongst professional …
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Born she is the divine Christ child : female figurations of Christ in Black Atlantic literature, theatre, and cinema
… semi-god of capitalism under the protective cloak of the Christianizing mission. In my analysis of works, I offer a comparative analysis of the rewriting of the Christ narrative in three novels: Toni Morrison's Paradise (1998), Simone Schwarz-Bart's Pluie et vent sur Telumée miracle (1972), …
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The liability of directors for fraudulent and/or reckless trading: Section 424 of the Companies Act 61 of 1973
… have come under the_ spotlight as a 'cloak' and a 'sham', 1 the fact remains that a company as a separate legal personality comes into existence on the date of incorporation and that no recourse can be f6unded on the proposition that a company's misdemeanours cause it ipso facto to …
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Electromagnetic waves in nonlinear and linear magnetooptic metamaterials
… field has developed recently.The way in which cloaking devices are implemented is described, and the possibility ofadding a magnetooptic switching functionality to the standard electromagnetic cloak ispresented. Finally, conclusions are given and some comments about the future directionsare …
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Coherent effects in wave propagation through complex media
… used to uncover an object hidden by a diffusive cloak inside a strong scattering medium. It is shown that it is possible to detect the size and position, including the depth, of the object unknown apriori. In addition, a theoretical model is developed to predict the geometry dependence of the …
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Geometric manipulation of light : from nonlinear optics to invisibility cloaks
… Second, we consider proposals for invisibility cloaks to change the path of electromagnetic waves in a certain way so that the object appears invisible at a certain frequency or a range of frequencies. Transformation-based invisibility cloaks make use of the coordinate invariance of Maxwell's …
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