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 40 for “"Cloaking"”.
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Practical electron cloaking in solids
… processing etc. The invisibility effect, or "cloaking effect", is one of the most striking demonstrations of the unprecedented ability of manipulating light provided by optical metamaterials. As a natural extension, the cloaking effect of acoustic waves and quantum matter waves has also been …
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Cloaking fabric, a confidentiality layer for hyperledger fabric
… a confidentiality layer on top of it. We present Cloaking Fabric, an extension to the popular permissioned blockchain Hyperledger Fabric that utilizes HoneybadgerMPC and HoneybadgerAVSS to provide a confidentiality layer that would allow smart-contracts on the blockchain to interact with private …
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Graphene Based Metamaterials For Terahertz Cloaking And Subwavelength Imaging
… cylindrical graphene metasurface is utilized for cloaking of several concentric finite conducting wedges. In addition, a wedge shaped metasurface is proposed as an alternative approach for cloaking of finite wedges. The resolution of the conventional imaging lenses is restricted by the natural …
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Artificial Impedance Surfaces and Wire Media for Absorption and Cloaking
… surfaces and wire media for absorption and cloaking applications. The dissertation includes two parts which focus on the electromagnetic wave propagation in absorbers formed by stacked metasurfaces and structured wire media, and electromagnetic wave interaction with the cylindrical cloaking …
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The function of passive debris cloaking in tiny beetles (Coleoptera: Zopheridae)
… debris, termed here as ‘passive debris cloaking’. Passive debris cloaking is widespread amongst many different and unrelated taxa globally. It is suspected to be a form of crypsis, but there is very little evidence supporting this. Here, I used beetles of the family Zopheridae as a model …
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Using Maximally-Flat and Genetic Algorithm Solutions to Achieve Wideband Radar Cloaking
… for designing wave absorbing and radar cloaking systems, and measurements of ambient RF energy in four Duke buildings to gauge the feasibility of harvesting energy from RF band.</p><p>The first part of introduction provides a short recap of radar, electromagnetic wave absorbers, and its …
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Benjamin Britten’s compositions for children and amateurs: cloaking simplicity behind the veil of sophistication.
The principal aim of this thesis is to examine a portion of Britten’s oeuvre which was intended for performance by children and amateurs and thereby to assess the extent of the composer’s success in achieving music which betrayed all the hallmarks of a sophisticated composition, yet providing a …
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Novel Cladding Designs for Engineering Electromagnetic Scattering
… antenna designs and electromagnetic cloaking. In this thesis, we propose antenna systems that address the inherent challenges associated with impedance matching and radiation/reception efficiency. By enclosing the antenna with suitably designed spherical metamaterials or ultrathin …
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Geometric manipulation of light : from nonlinear optics to invisibility cloaks
… the cloak. We study the practical limitations of cloaking as a function of the size of the object being cloaked. Specifically, we study the bandwidth, loss, and scattering limitations of cloaking as the object gets larger and show that cloaking of objects many times larger than the wavelength in …
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Design optimization of acoustic metamaterials and phononic crystals with a time domain method
… conducted on the design of a broadband acoustic cloaking device.
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Advances in Complex Electromagnetic Media
… and both magnetic and electric response. Thus, a cloaking cross-section measurement provides a useful way to quantify advancements in the effective medium theories which form the basis for metamaterials. I report on the first such measurements, performed on the original microwave cloaking design. …
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Investigation of defects on acoustic scattering in cloak by molding process
… that the broken cloak could accomplish the cloaking function depending on the direction of defects. Moreover, this study of microcasting process for the mass production and investigation of the defects in the acoustic cloak may apply to the understanding of the broken symmetric effects of an …
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“Life Out of Death": Poisons, Antidotes, and the Medical Marketplace in Christina Rossetti's “Goblin Market"
… of toxicology, poisons, and antidotes and cloaking her critique of the medical marketplace of Victorian England and Victorian male medical professionals in allegorical and fantastical elements. This unique combination of literal and allegorical is seen through Rossetti’s framing of the …
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Engineering physico-chemical interactions across drug delivery, agriculture and carbon capture
… lubrication by a less viscous fluid. Second, by cloaking spray droplets in minute quantities of plant oils (≤ 1wt%), we enhance energy dissipation during droplet impact on hydrophobic surfaces and demonstrate a 5x reduction in pesticide waste on a variety of plant leaves. Finally, mist-scale …
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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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Design and transformation of three dimensional pupils : diffractive and subwavelength
… by elliptical rod lattices; and with anisotropy, cloaking and accommodation of different components of an optical device become possible. Inhomogeneity is discussed in the context of gradient--index media. The additional thin--film wave guidance effect along the third dimension due to fabrication …
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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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Wave propagation and imaging in structured optical media
… photonic crystal fibers, to invisibility cloaking, to super-resolution imaging with metamaterials etc.</p> <p>In particular, structured optical media allow to manipulate the wave propagation and dispersion. In this thesis, we focus on engineering the propagation phase dispersion by …
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