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 36 for “"Supercells"”.
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Tornadogenesis And Tornadogenesis Failure In Numerically Simulated Supercells
… produced the strongest, longest-lived supercells.</p> <p> Twenty-one tornadic simulations were examined. It was found that 0-3 km storm relative environmental helicity was the best predictor of the intensity (i.e. maximum pressure drop) and duration of the simulated tornadoes. A …
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Investigating the longevity of significant-tornado producing supercells
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2022-11-11 without embargo terms
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Understanding tornado intensity in supercells and quasi-linear convective systems
Identifying storms capable of producing strong to violent tornadoes remains a focus of severe weather research due to their potentially significant impacts on life and property. The three parts of this dissertation contribute to new understanding of the controls on, and operational anticipation of, …
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Effects of Microphysical Parameterizations and Drop Breakup on Supercells and Supercell Cold Pools.
Ensemble Kalman filter data assimilation experiments are conducted using velocity data from the National Weather Service Radar 88-D and a Shared Mobile Atmospheric Research and Teaching Radar to determine how two different two-moment (Morrison and Milbrandt-Yau) microphysical parameterizations …
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Mesoscale and stormscale ingredients of tornadic supercells producing long-track tornadoes in the 2011 Alabama super outbreak
… on the environmental and stormscale dynamics of supercells that produce long-track tornadoes, with modeling emphasis on the central Alabama storms from April 27, 2011 - part of the 2011 Super Outbreak. While most of the 204 tornadoes produced on this day were weaker and short-lived, this outbreak …
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An investigation of the development of supercells in the Indiana and Ohio tornado outbreak of 24 August 2016 using a WRF model simulation
… convection transitioned to surface-based supercells between 1700 and 1830 UTC, after which time tornadoes began to occur. Such a transition is of particular interest owing to its relatively rare occurrence and because most convection-allowing models failed to predict it in this case, …
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Effects of environmental shear and buoyancy on simulated supercell interactions
… mode, higher buoyancy produced less classic supercells while higher shear produced more classic supercells. High precipitation supercells were favored with two-cell simulations where the second cell was directly to the southwest of the control cell. Secondary cells that were close to the con- …
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The impact of midlevel shear vector orientation on the longevity of and streamwise vorticity current formation within simulated supercells with freeslip and semi-slip lower boundaries
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2023-12-04 without embargo terms
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Assessing the impacts of microphysical and environmental controls on simulated supercell storms
… Although these hazards are not unique to supercells, some of them are often at their strongest when supercell-produced. Because of the destructive power of supercell hazards, supercells have been the subject of scientific research for decades. In this thesis, two of these hazards will be …
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Understanding the properties of the interface between graphene and transition metal oxide thin films using first principle approaches
… based on density functional theory. Various supercells of graphene were modelled and, optimized and their properties were calculated. The results show that different graphene supercells have di erent electronic and optical properties. When graphene is incorporated into a brookite TiO2, the …
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Impact Of Choices When Creating Average Proximity Soundings As Applied To Lp/cl/hp Supercell Environments
… cases were simulated--10 CL, 10 LP, and 9 HP supercells-- and only three storms in each class lasted at least 7200 seconds with an updraft helicity greater than 480 m2 s-2. Only two of these nine individual cases produced long lived supercells, one each from the LP and HP sounding classes, …
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Investigating the Existence of Coherent Phonon Scattering in Silicon Using Phononic Crystals
… of coherent phonon scattering. Each of the supercells had nearly identical critical lengths in order to keep the amount of incoherent scattering equal among all of the PnCs. Porosity differences among the supercells were also minimized. All of the PnCs were fabricated with a focused ion beam …
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Charge Density Waves and Superconductivity in Rare Earth Compounds from First Principles
… Tc estimation methods and use them for larger supercells which indicate Tc's up to 220 K may be possible in the doped RH3 system.
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How does terrain influence the upscale convective growth of orographic deep moist convection?
… raised, convection initiation occurred earlier, supercells were wider and more intense, and upscale convective growth generally occurred faster. A direct influence of terrain was blocking of cold pools leading to a deepening of the cold pools that drove surging outflow and more rapid upscale …
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“If it happened in…” a pseudo-global warming assessment of tropical cyclone tornadoes
… were found to have hook appendages resembling supercells found in non-tropical environments. The cells produced storm tops of 13 km, with rotating cores with depths of 4 to 6 km. Doppler-radar-derived rotation tracks, which have been found to be useful to identify and track mesocyclones in …
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Assessing electronic transport in solid materials via the fluctuation-dissipation theorem
… degrees of freedom and large real-space supercells for the vibrational ones. This is especially challenging for the charge transport coefficient of intrinsic semiconductors with dispersive electronic structures, because the free carriers are very localised in 𝐤-space, which demands an …
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Terrain and Landcover Effects of the Southern Appalachian Mountains on the Low-Level Rotational Wind Fields of Supercell Thunderstorms
… for smaller-scale severe weather phenomena like supercells and tornadoes. This study examines how complex terrain may have influenced the rotational low-level wind fields of fourteen supercell thunderstorms in the Appalachians. The terrain variables include elevation, land cover, slope, and …
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A study of the elastic and electronic properties of III-nitride semiconductors
… binding calculations on large ( 80,000 atoms) supercells. The theoretical framework used accounts for local strain and polarisation fluctuations arising from random alloy effects and possesses the computational efficiency needed for the calculation of many electronic states for realistic QW …
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First-principles Studies of Lattice Vibration and Electron Topology
… phonon sampling scheme based on non-diagonal supercells is proposed for the first time, which minimises the computational cost of phonon calculations and provides higher momentum resolution. Through this approach, we demonstrate that an accurate description of phonons in heavy metal compounds …
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First principle study of Nax[TiyZnzMnw]O2 as a cathode material for sodium-ion batteries
… NaxMn0.5Ti0.5O2 and 2 X 1 X 1 NaxMn 0.5Zn 0.5O2 supercells. The effects of dopants Ti and Zn on the NaXMnO2 stretch the lattice v parameters, resulting in volume expansion, this is because the atomic radii of the dopants are not the same as those of the host Mn. The electronic properties of the …
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