Thesis--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references (p.53-58).

Thesis (M.S.)--Montana State University--Bozeman, 2005. / Typescript. Chairperson, Graduate Committee: Jerry Stephens. Includes bibliographical references (leaves 104-106).

An assessment is made of the impact of a thermally bloomed atmosphere on target image quality. The steady-state phase perturbations due to blooming and the effects of the distortion on return wave-fronts are determined using a physical optics propagation code. The wavelength of the return radiation used to sense the distortions is shown to be an important consideration in the stability of the return image. The return targets images for several realistic scenarios are reconstructed based on the incoherent point spread function for each isoplanatic region of the object (target) plane. Special requirements of the back propagation algorithm are discussed with respect to "point source" geometry, tilt, tilt sensitivity, and isoplanatism criterion. The wave optics approach is shown to agree with the experimental results in regards to image blur and distortion. The stability of the reconstructed images is discussed using merit functions defining the amount of blur, distortion, and degradation in peak irradiance. The merit functions are shown to correlate well with the scenario distortion number used to define the degree of blooming induced in the forward propagation.

Thesis (M.S.)--Florida State University, 2004. / Advisor: Dr. Zhiyong Liang, Florida State University, FAMU-FSU College of Engineering, Dept. of Industrial Engineering and Manufacturing Engineering. Title and description from dissertation home page (viewed Sept. 27, 2004). Includes bibliographical references.

Thesis (M.S.)--Florida State University, 2005. / Advisor: Namas Chandra, Florida State University, College of Engineering, Dept. of Mechanical Engineering. Title and description from dissertation home page (viewed Jan. 25, 2006). Document formatted into pages; contains x, 54 pages. Includes bibliographical references.

Thesis (M.S.)--Montana State University--Bozeman, 2007. / Typescript. Chairperson, Graduate Committee: Christopher H. Jenkins. Includes bibliographical references (leaves 60-61).

Thesis (Ph. D.)--University of Oregon, 2006. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 208-221). Also available for download via the World Wide Web; free to University of Oregon users.

Neste trabalho, é apresentada uma rotina de simulação de redes aleatórias de carbono, com hibridização variável, orientada ao cálculo do coeficiente de expansão térmica. O método utiliza um algoritmo para geração de redes aleatórias de carbono além da técnica da aproximação quasi-harmônica que, associada ao potencial parametrizado AIREBO, foram empregados para a simulação. Utilizando esta abordagem, foi gerado um conjunto de 33 estruturas, compostas por 32 átomos, e com teores variáveis de carbono sp, sp2, sp3, para as quais determinou-se o coeficiente de expansão térmica volumétrico em um intervalo de temperatura de 0 a 500 K. Os resultados obtidos sugerem que, para este número de átomos por supercela de simulação, o coeficiente de expansão térmica não depende somente do percentual de hibridização do carbono e, em princípio, isto é atribuído ao limite termodinâmico do sistema não ter sido atingido. Por fim, foi possível identificar que, em casos específicos de estruturas onde foram mantidos os percentuais de carbono sp2, aspectos como a quantidade de carbono sp influenciam no coeficiente de expansão térmica. / Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2017-12-11T15:19:31Z No. of bitstreams: 1 Dissertacao Julio Ben.pdf: 4114324 bytes, checksum: 46d45c870dc5772be06001a414bc0d96 (MD5) / Made available in DSpace on 2017-12-11T15:19:31Z (GMT). No. of bitstreams: 1 Dissertacao Julio Ben.pdf: 4114324 bytes, checksum: 46d45c870dc5772be06001a414bc0d96 (MD5) Previous issue date: 2017-12-06 / In this work, a simulation routine of carbon random networks, with variable hybridization, oriented to calculate the coeÿcient of thermal expansion, is presented. The method uses an algorithm for the generation of carbon random networks in addition to the quasi-harmonic approximation that, associated with the interatomic potential AIREBO, were used for the simulation. Using this approach, a set of 33 structures, composed of 32 atoms, with variable sp, sp2, sp3 carbon contents were generated and the respective volumetric thermal expansion coeÿcients were determined in a temperature range from 0 to 500 K. The results obtained suggest that, for this number of atoms per supercell, the coeÿcient of thermal expansion does not depend only on the percentage of carbon hybridization and, in principle, this is attributed to the thermodynamic limit of the system not being reached. Finally, it was possible to identify, in specific cases of structures where the percentages of sp2 carbon were maintained, that aspects such as the amount of sp carbon have influence on the coeÿcient of thermal expansion.

Neste trabalho, é apresentada uma rotina de simulação de redes aleatórias de carbono, com hibridização variável, orientada ao cálculo do coeficiente de expansão térmica. O método utiliza um algoritmo para geração de redes aleatórias de carbono além da técnica da aproximação quasi-harmônica que, associada ao potencial parametrizado AIREBO, foram empregados para a simulação. Utilizando esta abordagem, foi gerado um conjunto de 33 estruturas, compostas por 32 átomos, e com teores variáveis de carbono sp, sp2, sp3, para as quais determinou-se o coeficiente de expansão térmica volumétrico em um intervalo de temperatura de 0 a 500 K. Os resultados obtidos sugerem que, para este número de átomos por supercela de simulação, o coeficiente de expansão térmica não depende somente do percentual de hibridização do carbono e, em princípio, isto é atribuído ao limite termodinâmico do sistema não ter sido atingido. Por fim, foi possível identificar que, em casos específicos de estruturas onde foram mantidos os percentuais de carbono sp2, aspectos como a quantidade de carbono sp influenciam no coeficiente de expansão térmica. / In this work, a simulation routine of carbon random networks, with variable hybridization, oriented to calculate the coeÿcient of thermal expansion, is presented. The method uses an algorithm for the generation of carbon random networks in addition to the quasi-harmonic approximation that, associated with the interatomic potential AIREBO, were used for the simulation. Using this approach, a set of 33 structures, composed of 32 atoms, with variable sp, sp2, sp3 carbon contents were generated and the respective volumetric thermal expansion coeÿcients were determined in a temperature range from 0 to 500 K. The results obtained suggest that, for this number of atoms per supercell, the coeÿcient of thermal expansion does not depend only on the percentage of carbon hybridization and, in principle, this is attributed to the thermodynamic limit of the system not being reached. Finally, it was possible to identify, in specific cases of structures where the percentages of sp2 carbon were maintained, that aspects such as the amount of sp carbon have influence on the coeÿcient of thermal expansion.

New ultra-low thermal expansion materials, based on the NZP structure, have been developed and evaluated for future application in ceramic diesel engines which require exceptional thermal shock resistance. Twenty-four cation substitutions, with electron valence ranging from +1 to +5, were used to replace Na⁺ in the NZP skeletal framework. The linear thermal expansion measurements were conducted for ternary systems up to 1000°C. Quarternary & quinternary compounds were processed using combinations of alkali-alkali, alkali-alkaline earth, and alkaline earth alkaline earth instead of Na⁺. These were evaluated for solid solubility. Linear thermal expansion values were obtained for those compositions having single phase composition. Axial thermal expansion measurements were conducted using high temperature XRD for compounds having low linear thermal expansion value from room temperature to 1400°C. Several ultra-low expansion materials (less than 10x10⁻⁷/°C in absolute value) were found, which also had axial thermal expansion anisotropy. ‘ The effects of ionic size and valence of the substitution elements are discussed to explain the linear thermal expansion behavior and thermal expansion anisotropy investigated in these compounds. The effect of crystallinity is discussed, and the unit-cell equilibrium is suggested to interpret the general thermal expansion behavior occurring in crystalline solids. Secondary material properties for the compounds Rb_0.5Cs_0.5Zr₂(PO₄)₃ & Ca_0.5Mg_0.5Zr₄(PO₄)₆ with linear thermal expansion values of -0.3x10⁻⁷/°C & -5x10⁻⁷/°C, respectively, have also been characterized. / Ph. D.