In the Asian and other monsoon regions of the world most of the severe weather observed is local or mesoscale in nature. Forecasting convective storms or mesoscale systems in the monsoon regions, especially in the tropics, has always been a challenging task to operational meteorologists. Maldives Islands, being situated in the tropical Indian Ocean, are affected by monsoon depressions and tropical cyclones. Thunderstorms and the passage of squall lines are well known sources of heavy rainfall. However, due to the lack of professional people and necessary equipment the weather systems around these islands are seldom studied. Therefore the aim of this thesis is to investigate whether the small islands can create sufficient perturbations in the mesoscale environment to result in the development of convective systems. In this regard, two numerical models, Weather Research and Forecasting model (WRF version 2.2.1) and Regional Atmospheric Modelling System (RAMS version 6.0) were used in this study. Two experiments were performed using the WRF model. In the first experiment, a case study was investigated where the selected day experienced heavy rainfall and thunderstorms. In the second experiment, the same case study was used but with the topographical and surface properties removed in order to investigate the influence of the island in modifying the mesoscale environment. All the experiments were initialized using the re-analysis data from NECP. WRF was able to predict the large scale synoptic features with reasonable accuracy when compared to the observations. Development of the boundary layer and the downstream advection of the temperature anomaly generated by the island were well represented. However, the magnitude of the effects was shown to be weak, probably due to the influence of large scale synoptic features. Even though the model was able to predict the large scale features and some of the mesoscale features, it did not predict any storm development and underestimated the precipitation. Therefore, it was decided to idealize the storm development using the RAMS model. RAMS model was used in a two-dimensional framework. The model was initialized horizontally homogenous using a single sounding and six simulations were performed. The simulation results clearly depicted that the small island can generate its own circulation and influence the mesoscale environment. The daytime heating of the island and the downstream advection of the temperature anomaly in a moist unstable atmosphere could trigger a thunderstorm later in the day. The storm becomes mature approximately 40-80 km offshore. This also suggests that triggering of a storm on one side of an atoll could influence the islands on the downstream side. Sensitivity of storm development to the thermodynamics showed that even with an unstable atmosphere, enough moisture in the lower and mid-troposphere is needed to trigger the storm. Sensitivity to the change of SST showed that convective development was suppressed with a drop of 1 oC. However, this needs further investigation. Assessment of sensitivity to the size of the island showed that the time of triggering of the storm was later and the scale of influence was smaller with a smaller island.

Optical tweezers using highly focussed laser beams can be used to exert forces and torques and thus drive micromachines. This opens up a new field of microengineering, whose potential has yet to be fully realized. Until now, methods that have been used for modelling optical tweezers are limited to scatterers that are homogeneous or that have simple geometry. To aid in designing more general micromachines, I developed and implemented two main methods for modelling the micromachines that we use. These methods can be used for further proposed structures to be fabricated. The first is a FDFD/T-matrix hybrid method that incorporates the finite difference frequency domain (FDFD) method, which is used for inhomogeneous and anisotropic media, with vector spherical wave functions (VSWF) to formulate the T-matrix. The T-matrix is then used to calculate the torque of the trapped vaterite sphere, which is apparently composed of birefringent unit crystals but the bulk structure appears to be arranged in a sheaf-of-wheat fashion. The second method is formulating the T-matrix via discrete dipole approximation (DDA) of complex arbitrarily shaped mesoscale objects and implementing symmetry optimizations to allow calculations to be performed on high-end desktop PCs that are otherwise impractical due to memory requirements and calculation time. This method was applied to modelling microrotors. The T-matrix represents the scattering properties of an object for a given wavelength. Once it is calculated, subsequent calculations with different illumination conditions can be performed rapidly. This thesis also deals with studies of other light scattering phenomena including the modelling of scattered fields from protein molecules subsequently used to model FRET resonance, determining the limits of trappability, interferometric Brownian motion and the comparison between integral transforms by direct numerical integration and overdetermined point-matching.

Optical tweezers using highly focussed laser beams can be used to exert forces and torques and thus drive micromachines. This opens up a new field of microengineering, whose potential has yet to be fully realized. Until now, methods that have been used for modelling optical tweezers are limited to scatterers that are homogeneous or that have simple geometry. To aid in designing more general micromachines, I developed and implemented two main methods for modelling the micromachines that we use. These methods can be used for further proposed structures to be fabricated. The first is a FDFD/T-matrix hybrid method that incorporates the finite difference frequency domain (FDFD) method, which is used for inhomogeneous and anisotropic media, with vector spherical wave functions (VSWF) to formulate the T-matrix. The T-matrix is then used to calculate the torque of the trapped vaterite sphere, which is apparently composed of birefringent unit crystals but the bulk structure appears to be arranged in a sheaf-of-wheat fashion. The second method is formulating the T-matrix via discrete dipole approximation (DDA) of complex arbitrarily shaped mesoscale objects and implementing symmetry optimizations to allow calculations to be performed on high-end desktop PCs that are otherwise impractical due to memory requirements and calculation time. This method was applied to modelling microrotors. The T-matrix represents the scattering properties of an object for a given wavelength. Once it is calculated, subsequent calculations with different illumination conditions can be performed rapidly. This thesis also deals with studies of other light scattering phenomena including the modelling of scattered fields from protein molecules subsequently used to model FRET resonance, determining the limits of trappability, interferometric Brownian motion and the comparison between integral transforms by direct numerical integration and overdetermined point-matching.

In the Asian and other monsoon regions of the world most of the severe weather observed is local or mesoscale in nature. Forecasting convective storms or mesoscale systems in the monsoon regions, especially in the tropics, has always been a challenging task to operational meteorologists. Maldives Islands, being situated in the tropical Indian Ocean, are affected by monsoon depressions and tropical cyclones. Thunderstorms and the passage of squall lines are well known sources of heavy rainfall. However, due to the lack of professional people and necessary equipment the weather systems around these islands are seldom studied. Therefore the aim of this thesis is to investigate whether the small islands can create sufficient perturbations in the mesoscale environment to result in the development of convective systems. In this regard, two numerical models, Weather Research and Forecasting model (WRF version 2.2.1) and Regional Atmospheric Modelling System (RAMS version 6.0) were used in this study. Two experiments were performed using the WRF model. In the first experiment, a case study was investigated where the selected day experienced heavy rainfall and thunderstorms. In the second experiment, the same case study was used but with the topographical and surface properties removed in order to investigate the influence of the island in modifying the mesoscale environment. All the experiments were initialized using the re-analysis data from NECP. WRF was able to predict the large scale synoptic features with reasonable accuracy when compared to the observations. Development of the boundary layer and the downstream advection of the temperature anomaly generated by the island were well represented. However, the magnitude of the effects was shown to be weak, probably due to the influence of large scale synoptic features. Even though the model was able to predict the large scale features and some of the mesoscale features, it did not predict any storm development and underestimated the precipitation. Therefore, it was decided to idealize the storm development using the RAMS model. RAMS model was used in a two-dimensional framework. The model was initialized horizontally homogenous using a single sounding and six simulations were performed. The simulation results clearly depicted that the small island can generate its own circulation and influence the mesoscale environment. The daytime heating of the island and the downstream advection of the temperature anomaly in a moist unstable atmosphere could trigger a thunderstorm later in the day. The storm becomes mature approximately 40-80 km offshore. This also suggests that triggering of a storm on one side of an atoll could influence the islands on the downstream side. Sensitivity of storm development to the thermodynamics showed that even with an unstable atmosphere, enough moisture in the lower and mid-troposphere is needed to trigger the storm. Sensitivity to the change of SST showed that convective development was suppressed with a drop of 1 oC. However, this needs further investigation. Assessment of sensitivity to the size of the island showed that the time of triggering of the storm was later and the scale of influence was smaller with a smaller island.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O picoplâncton (0,2 - 2,0 m) e ultraplâncton (> 2,0 - 5,0 m) despertam interesse por utilizarem ativamente a matéria orgânica dissolvida, estabelecendo a alça microbiana. Responsáveis por 50-80% da produção primária em águas oligotróficas, essas frações apresentam elevadas eficiência luminosa e razão superfície/volume que as permitem alcançar alto desenvolvimento mesmo sob baixas luminosidade e disponibilidade de nutrientes. Buscando relacionar a distribuição espacial e composição da comunidade pico e ultraplanctônica aos controles bottom-up na plataforma continental e talude ao largo dos Estados do Rio de Janeiro e São Paulo (22S a 26S), foram coletadas amostras de água em 39 estações oceanográficas e utilizadas as imagens dos sensores MODIS Terra e Aqua, bem como dados de hidrografia, para a descrição dos fenômenos oceanográficos de mesoescala. A abundância total de ambas as frações de tamanho, assim como a dominância do picoplâncton, reduziu em função do distanciamento da costa. Os organismos autotróficos foram em média (102 cél.mL-1 a 104 cél.mL-1 ) majoritariamente uma ordem de grandeza inferiores aos heterotróficos (103 cél.mL-1 a 105 cél.mL-1). A Água Central do Atlântico Sul (ACAS) e as plumas das baías de Guanabara e Sepetiba (RJ) permaneceram na plataforma interna favorecendo o aumento na concentração dos macronutrientes e refletindo na mudança da estrutura da comunidade através do aumento da contribuição de autótrofos no centro da plataforma, principalmente do ultraplâncton à superfície (cerca de 21%) e na profundidade do máximo de clorofila (44%). O transporte de águas costeiras carreadas por uma corrente de origem sul gerou o vórtice de plataforma identificado nas imagens de satélite para a região da plataforma interna de Ubatuba (SP), onde concentrações mais elevadas de amônio (0,28 M) e fosfato (9,64 M) a partir dos 50 m sustentaram maior densidade do ultra autótrofo (2,89 x 103 cél.mL-1) que superou a densidade de heterótrofos (2,50 x 103 cél.mL-1) no máximo de clorofila. Os resultados destacaram um forte gradiente nerítico-oceânico na distribuição dos organismos. Sugerem ainda a predominância do metabolismo heterotrófico na maior parte das águas oligotróficas da plataforma e talude entre o Rio de Janeiro e São Paulo, bem como a presença de caráter autotrófico naquelas regiões influenciadas por feições de mesoescala, como plumas estuarinas e vórtices de plataforma. / The picoplankton (0.2 2.0 m) and ultraplankton (>2.0 5.0 m) arouse interest because they actively use the dissolved organic matter and establishe the microbial loop. Responsible for 50-80% of primary production in oligotrophic waters, these fractions have high luminous efficiency and high surface/volume ratio that enable them to achieve high development even under low light and low nutrient availability. Seeking to relate the spatial distribution and composition of pico and ultraplanktonic community to the bottom-up control and mesoscale oceanographic features in the Brazilian continental shelf and slope off Rio de Janeiro and São Paulo (22S to 26S), water samples were taken in 39 oceanographic stations and images of MODIS Terra and Aqua sensors, toghether with hidrography, were employed to decribe the mesoscale oceanographic features.The total abundance of both size fractions, as well as the dominance of picoplankton, decreased as a function of distance from the coast. Autotrophic organisms were, predominantly, on average (102 cell.mL-1 to 104 cell.mL-1) one order of magnitude lower than the heterotrophic (103 cell.mL-1 to 105 cell.mL-1). The South Atlantic Central Water (SACW) and the plumes of Guanabara and Sepetiba bays (RJ) remained in the inner shelf favoring an increase in macronutrients concentration and reflecting changes in community structure by the increase of autotrophs contribution, especially in the central portion of the shelf, mainly ultraplankton at surface (21%) and in maximum chlorophyll depth (44%). The transport of coastal waters carried by a current from south caused the shelf eddy identified by water colour/chlorophyll images for the region of Ubatuba inner shelf (SP), where high concentrations of ammonium (0,28 M) and phosphate (9,64 M) near the depth of 50 m supported higher density of autotrophic ultraplankton (2.89 x 103 cells.mL-1) which exceeded the density of heterotrophs at the chlorophyll maximum (2.19 x 103 cells.mL-1). Our results highlighted a strong neritic-oceanic gradient in the distribution of these organisms. They also suggest the predominance of the heterotrophic metabolism in the majority of the oligotrophic waters of the shelf and slope between Rio de Janeiro and São Paulo, as well as the presence of an autotrophic nature in those regions influenced by mesoscale features, such as estuarine plumes and shelf eddies.

abstract: This study considered the impact of grid resolution on wind velocity simulated by the Weather Research and Forecasting (WRF) model. The period simulated spanned November 2009 through January 2010, for which, multi-resolution nested domains were examined. Basic analysis was performed utilizing the data assimilation tools of NCEP/NCAR (National Center for Environmental Prediction/National Center for Atmospheric Research) to determine the ideal location to examine during the simulation was the Pacific Northwest portion of the United States, specifically the border between California and Oregon. The simulated mutli-resolution nested domains in this region indicated an increase in apparent wind speed as the resolution for the domain was increased. These findings were confirmed by statistical analysis which identified a positive bias for wind speed with respect to increased resolution as well as a correlation coefficient indicating the existence of a positive change in wind speed with increased resolution. An analysis of temperature change was performed in order to test the validity of the findings of the WRF simulation model. The statistical analysis performed on temperature change throughout the increased grid resolution did not indicate any change in temperature. In fact the correlation coefficient values between the domains were found in the 0.90 range, indicating the non-sensitivity of temperature across the increased resolutions. These results validate the findings of the WRF simulation: increased wind velocity can be observed at higher grid resolution. The study then considered the difference between wind velocity observed over the entire domains and the wind velocity observed solely over offshore locations. Wind velocity was observed to be significantly higher (an increase of 68.4%) in the offshore locations. The findings of this study suggest simulation tools should be utilized to examine domains at a higher resolution in order to identify potential locations for wind farms. The results go further to suggest the ideal location for these potential wind farms will be at offshore locations. / Dissertation/Thesis / M.S. Mechanical Engineering 2012

Cette thèse s’inscrit dans le cadre du projet européen 3D-LightTrans ayant pour objectifs la fabrication à grande à échelle et à bas coût de pièces composites. Pour parvenir à ces objectifs, des semi-produits sous forme de tissus 3D de mèches comélées ont été réalisés. Le but de ces travaux est de caractériser le comportement mécanique de ces tissus en vue d’analyser leur formabilité et d’être en mesure de prédire leur comportement pendant les processus de mise en forme utilisés lors de la fabrication des pièces composites. Le premier objectif de ces travaux était de caractériser expérimentalement le comportement mécanique des tissus 3D. Après avoir effectué un état de l’art ayant permis de définir les types et paramètres d’essais à utiliser pour la caractérisation du comportement des tissus, l’analyse des résultats de ces différents essais a permis de mettre en évidence les spécificités du comportement des tissus 3D. Le deuxième objectif des travaux était de modéliser le comportement des tissus par une approche numérique. Le choix s’étant porté sur une approche à l’échelle mésoscopique, le comportement mécanique des mèches comélées a été caractérisé expérimentalement. Les limitations du logiciel GeoFab quant à son utilisation pour la génération de modèles CAO de mailles élémentaires de tissus 3D ont été identifiées. Des améliorations permettant de répondre à ces limitations ont été proposées et leur faisabilité démontrée. Un modèle CAO d’une sous partie de la maille élémentaire d’un des tissus a alors été généré. Après avoir modélisé le comportement des mèches comélées en se basant sur les résultats de leur caractérisation expérimentale, des premières simulations éléments finis ayant permis d’obtenir des résultats encourageants ont été réalisés. / This thesis is part of the European project 3D-LightTrans whose objectives are the large scale and low-cost manufacturing of composite parts. To achieve these goals, semi-finished products in the form of 3D fabrics of commingled yarns were produced. The purpose of this work is to characterize the mechanical behavior of these fabrics in order to investigate their formability and be able to predict their behavior during the forming processes used for the manufacturing of composite parts. The first objective of the work was to characterize experimentally the 3D fabrics mechanical behavior. A state of the art was realized in order to define the types and test parameters to use. The analysis of these test results allowed to highlight the specific 3D fabrics mechanical behaviour. The second objective of the work was to model the fabrics behavior using a numerical method. A mesoscopic scale approach having been selected, experimental characterization of the commingled yarns mechanical behavior was necessary. Then, GeoFab software limitations on its use for the generation of CAD models of 3D fabrics unit cells were identified. Improvements to address these limitations have been proposed and their feasibility was demonstrated. A CAD model of a sub part of one of the fabrics unit cell was then generated. After having modeled the commingled yarns behaviour using experimental results, finite element simulations were performed on fabric CAD model and first encouraging results were obtained.

xvii, 189 p. ： ill. (some col.) / Low-dimensional electronic systems, systems that are restricted to single energy levels in at least one of the three spatial dimensions, have attracted considerable interest in the field of thermoelectric materials. At these scales, the ability to manipulate electronic energy levels offers a great deal of control over a device's thermopower, that is, its ability to generate a voltage due to a thermal gradient. In addition, low-dimensional devices offer increased control over phononic heat flow. Mesoscale geometry can also have a large impact on both electron and phonon dynamics. Effects such as ballistic transport in a two-dimensional electron gas structure can lead to the enhancement or attenuation of electron transmission probabilities in multi-terminal junctions. The first half of this dissertation investigates the transverse thermoelectric properties of a four-terminal ballistic junction containing a central symmetry-breaking scatterer. It is believed that the combined symmetry of the scatterer and junction is the key component to understanding non-linear and thermoelectric transport in these junctions. To this end, experimental investigations on this type of junction were carried out to demonstrate its ability to generate a transverse thermovoltage. To aid in interpreting the results, a multi-terminal scattering-matrix theory was developed that relates the junction's non-linear electronic properties to its thermoelectric properties. The possibility of a transverse thermoelectric device also motivated the first derivation of the transverse thermoelectric efficiency. This second half of this dissertation focuses on heat flow phenomena in InAs/InP heterostructure nanowires. In thermoelectric research, a phononic heat flow between thermal reservoirs is considered parasitic due to its minimal contribution to the electrical output. Recent experiments involving heterostructure nanowires have shown an unexpectedly large heat flow, which is attributed in this dissertation to an interplay between electron-phonon interaction and phononic heat flow. Using finite element modeling, the recent experimental findings have provided a means to probe the electron-phonon interaction in InAs nanowires. In the end, it is found that electron-phonon interaction is an important component in understanding heat flow at the nanoscale. This dissertation includes previously unpublished co-authored material. / Committee in charge: Dr. Richard Taylor， Chair； Dr. Heiner Linke， Advisor； Dr. David Cohen， Member； Dr. John Toner， Member； Dr. David Johnson， Outside Member

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O picoplâncton (0,2 - 2,0 m) e ultraplâncton (> 2,0 - 5,0 m) despertam interesse por utilizarem ativamente a matéria orgânica dissolvida, estabelecendo a alça microbiana. Responsáveis por 50-80% da produção primária em águas oligotróficas, essas frações apresentam elevadas eficiência luminosa e razão superfície/volume que as permitem alcançar alto desenvolvimento mesmo sob baixas luminosidade e disponibilidade de nutrientes. Buscando relacionar a distribuição espacial e composição da comunidade pico e ultraplanctônica aos controles bottom-up na plataforma continental e talude ao largo dos Estados do Rio de Janeiro e São Paulo (22S a 26S), foram coletadas amostras de água em 39 estações oceanográficas e utilizadas as imagens dos sensores MODIS Terra e Aqua, bem como dados de hidrografia, para a descrição dos fenômenos oceanográficos de mesoescala. A abundância total de ambas as frações de tamanho, assim como a dominância do picoplâncton, reduziu em função do distanciamento da costa. Os organismos autotróficos foram em média (102 cél.mL-1 a 104 cél.mL-1 ) majoritariamente uma ordem de grandeza inferiores aos heterotróficos (103 cél.mL-1 a 105 cél.mL-1). A Água Central do Atlântico Sul (ACAS) e as plumas das baías de Guanabara e Sepetiba (RJ) permaneceram na plataforma interna favorecendo o aumento na concentração dos macronutrientes e refletindo na mudança da estrutura da comunidade através do aumento da contribuição de autótrofos no centro da plataforma, principalmente do ultraplâncton à superfície (cerca de 21%) e na profundidade do máximo de clorofila (44%). O transporte de águas costeiras carreadas por uma corrente de origem sul gerou o vórtice de plataforma identificado nas imagens de satélite para a região da plataforma interna de Ubatuba (SP), onde concentrações mais elevadas de amônio (0,28 M) e fosfato (9,64 M) a partir dos 50 m sustentaram maior densidade do ultra autótrofo (2,89 x 103 cél.mL-1) que superou a densidade de heterótrofos (2,50 x 103 cél.mL-1) no máximo de clorofila. Os resultados destacaram um forte gradiente nerítico-oceânico na distribuição dos organismos. Sugerem ainda a predominância do metabolismo heterotrófico na maior parte das águas oligotróficas da plataforma e talude entre o Rio de Janeiro e São Paulo, bem como a presença de caráter autotrófico naquelas regiões influenciadas por feições de mesoescala, como plumas estuarinas e vórtices de plataforma. / The picoplankton (0.2 2.0 m) and ultraplankton (>2.0 5.0 m) arouse interest because they actively use the dissolved organic matter and establishe the microbial loop. Responsible for 50-80% of primary production in oligotrophic waters, these fractions have high luminous efficiency and high surface/volume ratio that enable them to achieve high development even under low light and low nutrient availability. Seeking to relate the spatial distribution and composition of pico and ultraplanktonic community to the bottom-up control and mesoscale oceanographic features in the Brazilian continental shelf and slope off Rio de Janeiro and São Paulo (22S to 26S), water samples were taken in 39 oceanographic stations and images of MODIS Terra and Aqua sensors, toghether with hidrography, were employed to decribe the mesoscale oceanographic features.The total abundance of both size fractions, as well as the dominance of picoplankton, decreased as a function of distance from the coast. Autotrophic organisms were, predominantly, on average (102 cell.mL-1 to 104 cell.mL-1) one order of magnitude lower than the heterotrophic (103 cell.mL-1 to 105 cell.mL-1). The South Atlantic Central Water (SACW) and the plumes of Guanabara and Sepetiba bays (RJ) remained in the inner shelf favoring an increase in macronutrients concentration and reflecting changes in community structure by the increase of autotrophs contribution, especially in the central portion of the shelf, mainly ultraplankton at surface (21%) and in maximum chlorophyll depth (44%). The transport of coastal waters carried by a current from south caused the shelf eddy identified by water colour/chlorophyll images for the region of Ubatuba inner shelf (SP), where high concentrations of ammonium (0,28 M) and phosphate (9,64 M) near the depth of 50 m supported higher density of autotrophic ultraplankton (2.89 x 103 cells.mL-1) which exceeded the density of heterotrophs at the chlorophyll maximum (2.19 x 103 cells.mL-1). Our results highlighted a strong neritic-oceanic gradient in the distribution of these organisms. They also suggest the predominance of the heterotrophic metabolism in the majority of the oligotrophic waters of the shelf and slope between Rio de Janeiro and São Paulo, as well as the presence of an autotrophic nature in those regions influenced by mesoscale features, such as estuarine plumes and shelf eddies.

abstract: In material science, microstructure plays a key role in determining properties, which further determine utility of the material. However, effectively measuring microstructure evolution in real time remains an challenge. To date, a wide range of advanced experimental techniques have been developed and applied to characterize material microstructure and structural evolution on different length and time scales. Most of these methods can only resolve 2D structural features within a narrow range of length scale and for a single or a series of snapshots. The currently available 3D microstructure characterization techniques are usually destructive and require slicing and polishing the samples each time a picture is taken. Simulation methods, on the other hand, are cheap, sample-free and versatile without the special necessity of taking care of the physical limitations, such as extreme temperature or pressure, which are prominent issues for experimental methods. Yet the majority of simulation methods are limited to specific circumstances, for example, first principle computation can only handle several thousands of atoms, molecular dynamics can only efficiently simulate a few seconds of evolution of a system with several millions particles, and finite element method can only be used in continuous medium, etc. Such limitations make these individual methods far from satisfaction to simulate macroscopic processes that a material sample undergoes up to experimental level accuracy. Therefore, it is highly desirable to develop a framework that integrate different simulation schemes from various scales to model complicated microstructure evolution and corresponding properties. Guided by such an objective, we have made our efforts towards incorporating a collection of simulation methods, including finite element method (FEM), cellular automata (CA), kinetic Monte Carlo (kMC), stochastic reconstruction method, Discrete Element Method (DEM), etc, to generate an integrated computational material engineering platform (ICMEP), which could enable us to effectively model microstructure evolution and use the simulated microstructure to do subsequent performance analysis. In this thesis, we will introduce some cases of building coupled modeling schemes and present the preliminary results in solid-state sintering. For example, we use coupled DEM and kinetic Monte Carlo method to simulate solid state sintering, and use coupled FEM and cellular automata method to model microstrucutre evolution during selective laser sintering of titanium alloy. Current results indicate that joining models from different length and time scales is fruitful in terms of understanding and describing microstructure evolution of a macroscopic physical process from various perspectives. / Dissertation/Thesis / Doctoral Dissertation Materials Science and Engineering 2018