This dissertation addresses the synthesis of oriented mesoporous ceramic films by evaporation induced self-assembly of surfactants and ceramic precursors in films dip coated from ethanol-rich sols. First, the kinetics of silica polycondensation in surfactant templated sol-gel films is studied both before and after deposition using infrared spectroscopy. These observations reveal an induction time (with minimal condensation rate) before curing begins in certain surfactant-templated silica films, which can be utilized to perform post-synthesis modification. This induction time is maximized at high humidity, and by long nonionic surfactant headgroups (rather than, for instance, a trimethylammonium headgroup). The second part of the dissertation addresses lattice Monte Carlo (MC) simulation of the effects of confinement on the 2D hexagonally close packed (HCP) phase formed by 60 vol% surfactant in a polar solvent. The effects of size and type of confining geometry (slit, cylindrical and spherical cavities) and of surface chemistry are simulated. The HCP mesophase orients orthogonal to chemically neutral surfaces which attract both head and tail of the surfactant equally. Novel mesophase geometries are simulated including radially oriented micelles, concentric helices, and concentric porous shells. Utilizing fundamental insights from the kinetics and MC studies, the third part of the dissertation describes the synthesis of silica films with orthogonally tilted HCP mesophase on chemically neutral surfaces. Crosslinking a random copolymer of polyethylene oxide (PEO)-polyproplyene oxide (PPO) on glass slides results in chemically neutral surfaces for the PEO-PPO-PEO triblock copolymer template (P123) used here. The orthogonal orientation of the HCP channels is confirmed using advanced x-ray scattering techniques and electron microscopy. The final part of the dissertation discusses applications of ceramic films with orthogonally tilted (ortho-) HCP mesophase. Silica membranes with ortho-HCP pores are prepared on porous alumina supports, and show permeability of ethanol orders of magnitude greater than films with parallel-oriented HCP channels. Size-selective filtration of gold nanoparticles confirms the absence of any nanoscale cracks in the membranes. For a second application, we prepare titania films with ortho-HCP mesopores. Careful crystallization of the films followed by spinning on an organic hole conducting polymer (P3HT) leads to active bulk heterojunction solar cells.

Indiana University-Purdue University Indianapolis (IUPUI) / Brain imaging genetics is an emerging research field aimed at studying the underlying genetic architecture of brain structure and function by utilizing different imaging modalities. However, not all the changes in the brain are a direct result of the genetic effect. Furthermore, the imaging phenotypes are promising for genetic analyses are usually unknown. In this thesis, we focus on identifying highly heritable measures of structural brain networks derived from Diffusion Weighted Magnetic Resonance imaging data. Using data for twins that is made available by the Human Connectome Project (HCP), the reliability of edge-level measures, namely fractional anisotropy, fiber length, and fiber number in the structural connectome, as well as seven network-level measures, specifically assortativity coefficient, local efficiency, modularity, transitivity, cluster coefficient, global efficiency, and characteristic path length, were evaluated using intraclass correlation coefficients. In addition, estimates of the heritability of the reliable measures were also obtained. It was observed that across all 64,620 network edges between 360 brain regions in the Glasser parcellation, approximately 5% were significantly high heritability based on fractional anisotropy, fiber length, or fiber number. Moreover, all tested network level measures, that capture network integrity, segregation, or resilience, were found to be highly heritable, having a variance ranging from 59% to 77% that is attributable to an additive genetic effect.

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Historically, the ability of crystal plasticity to incorporate the Schmid’s law at each integration point has been a powerful tool to simulate and predict the slip behavior at the grain level and the succeeding heterogeneous stress/strain localization and texture evolution at the macroscopic level. Unfortunately, this remarkable capability has not been replicated for materials where twinning becomes a noticeable deformation mechanism, namely in the case of low-stacking fault energy cubic, orthorhombic, and hexagonal close packed structures. This dissertation is an attempt to gain understanding on the heterogeneous deformation due to twinning through various techniques including micromechanics, discrete dislocation dipole loops, and digital image correlation (DIC) analyses, and then bring the collected small scale information up to the fullield crystal plasticity scale using fast Fourier Trans- forms. Results indicate that the twin spacing depends primarily upon the height of the twin, and the stress relaxation from the twinning depends upon the thickness of the twin. Furthermore, in a homogenous stress state, discrete dislocation dipole loop-based twinning model showed that the lenticular shape has the minimum stable energy rather than the lamellar or ellipsoidal twin morphology. Our study on the evolution of twinning under three-point bending condition in strongly basal textured magnesium alloy allowed us to build a strategy to incorporate characteristic twin spacing parameter in the crystal plasticity framework. Inspired by results from molecular dynamics (MD) simulations stressing the effect of shuffles on twin nucleation and disconnection core width, we developed an explicit twinning nucleation criterion based on hydrostatic stress gradient and volume fraction of twin inside a grain. Characteristic twin spacing parameter is used as a function of twin height to determine site specific nucleation points in case of multiple twinnings. This ap- proach offered a good reproduction of the microstructure evolution as affected by twinning in a tri-crystal system.

Le but de cette étude est de prédire la rupture de tôles en alliage de Zinc via des simulations par éléments finis. Pour ce faire, la caractérisation du comportement mécanique a été fait grâce à des essais de traction sur différentes nuances et orientation. Ces essais ont fait ressortir une grande anisotropie ainsi qu'un grande sensibilité à la vitesse de déformation et à la température. L'ensemble de ces données expérimentales est modélisé avec une loi de comportement de Norton Hoff et le critère de plasticité de Hill48. De plus la formabilité ainsi que son anisotropie ont été caractérisées avec des essais de traction, de traction plane et de gonflage hydraulique. Une grande anisotropie de formabilité, inédite dans la littérature, est observée. Celle-ci est modélisée via différents modèles de rupture issus de la littérature où que nous avons développés spécifiquement pour les alliages de Zinc. Enfin un modèle de rupture en contrainte, paraissant le plus adéquat pour la prédiction de la formabilité, a été choisi. Il a été ensuite implémenté dans le logiciel Forge2009®. Des essais académiques mais aussi industriels de mise en forme ont été simulé par le logiciel Forge2009® et ont donné de bonnes modélisations du comportement mécanique des tôles en alliage de Zinc ainsi que de bonnes prédictions de sa rupture. / The aim of this study is to predict the rupture of Zinc alloy sheets by the mean of Finite Element Method simulations. The mechanical behaviour of the material has been tested by tensile tests for several directions and for several Zinc grades. The materials show a high anisotropic mechanical response and high strain rate and temperature sensitivity. This set of experimental data has been modelled by the mean of the Norton Hoff law and the Hill 48 plastic criterion. Moreover, the formability has been tested by tensile and plane strain tests, and also hydraulic bulge tests. A high anisotropic formability, unseen in the literature, has been observed. This formability is modelled with different rupture criteria coming from the literature or specifically developed for the Zinc alloy study. A stress criterion model has been chosen to predict the formability. This criterion has been implemented into Forge2009® software. Academic and industrial forming processes have been simulated with Forge2009® and lead to an accurate description of the mechanical behaviour and the rupture localisation.

Pseudomonas syringae is a pathogen of numerous plant species, including several economically important crops. P. syringae pv. syringae B728a is a resident on leaves of common bean, where it utilizes several well-studied virulence factors, including secreted effectors and toxins, to develop a pathogenic interaction with its host. The B728a genome was recently sequenced, revealing the presence of 1,297 genes with unknown function. This dissertation demonstrates that a 29.9-kb cluster of genes in the B728a genome encodes a novel secretion pathway, the type VI secretion system (T6SS), that functions to deliver at least one protein outside of the bacterial cell. Western blot analyses show that this secretion is dependent on clpV, a gene that likely encodes an AAA+ ATPase, and is repressed by retS, which apparently encodes a hybrid sensor kinase. RetS and a similar protein called LadS are shown to collectively modulate several virulence-related activities in addition to the T6SS. Plate assays demonstrate that RetS negatively controls mucoidy, while LadS negatively regulates swarming motility. A mutation in retS affects B728a population levels on the surface of bean leaves. A model for the LadS and RetS control of B728a virulence activities is proposed, and possible roles for the B728a T6SS are addressed.

HCP materials are exceedingly being used as alloys and composites in several high strength light weight applications such as aerospace and aeronautical structures, deep sea maritime applications, and as biocompatible materials. To understand the deformation of HCP materials, reliable tools and techniques are required. One such technique is the Elasto-Plastic Self Consistency (EPSC) model. ESPC models use Eshelby’s Inclusion Theory as their basic formulation to model the strain experienced by a grain within a strained material sample. One of the oldest approximations (or models) used to model the grain’s strain within a strained sample is the Taylor’s Assumption (TA). TA assumes that each grain is strained to the same average value. EPSC models are different from the TA model since each grain modelled by the EPSC model would be strained to a different value. This is possible and obtained by solving an infinite domain boundary value problem. This key advantage of the EPSC model can therefore predict localized weak spots within material samples.EPSC models use the concept of eigen strain where the inhomogeneous grain is replaced with an equivalent inclusion. The technique proposed in this research is used to simulate uniaxial tension of rolled textured Magnesium. The number of deformation modes used in this research is seven. Both slipping systems and twinning systems are included in the simulation. The hardening phenomenon is described as a function of self-hardening as well as latent-hardening. As stated in (S. Kweon, 2020), modelling the interactive hardening requires a more robust numerical iterative technique. An improved robust iterative numerical technique is explained in (Daniel Raja, 2021) and (Soondo Kweon D. S., 2021). This research implements the equivalent inclusion theory in combination with the numerical iterative technique developed in the aforementioned papers.The report begins with the need for this research and advocates for the same. Then, the conceptional theories and the imaginary thought experiment performed by John D. Eshelby is presented. The concept of “Eigen Strain” which serves as the base work needed to understand and formulate the Equivalent Inclusion Theory is described in detail. The Equivalent Inclusion is then presented and developed. The concept of Green’s Function is presented and explained. These concepts serve as the building block for the derivation and calculation of the Eshelby Tensor which relates the concepts of eigen strain and constrained strain. The report concludes the theory section with the amalgamation of the ideas of the Green’s Function and Eigen Strain to develop the Eshelby Tensor for an Isotropic material as well as Anisotropic materials. In the following section, the unit cell accompanied with the deformation modes within the unit cell of an HCP material that are used in these simulations are presented. Following unit cell model, the crystal plasticity model which includes plastic deformation, hardening laws, and elastic deformation is elaborated. The results obtained from the simulation are presented and salient features are highlighted that are observed in the results. Lastly, the report concludes by pointing out key “take aways” from this research and identifies possible avenues for future research.Additionally, ten appendices are included towards the end of this report to enhance understanding of complicated derivations and solutions. Lastly, the author’s vita is included at the end of the report.

The manufacturing and the development of biotherapeutic drugs involves the expression of biotherapeutic proteins in a host cell expression system followed by a purification process. Bioanalytical methods to measure impurities such as host cell proteins (HCPs) are needed to obtain a robust process and a safe drug according to regulatory requirements. The aim of this project was to develop three specific HCP assays for detection and quantification of specific HCPsusing the Gyrolab® platform. The HCPs (Annexin A5, Clusterin and Nidogen-1) chosen for this project are generated from Chinese hamster ovary (CHO) cells. Each assay was evaluated on four different Gyrolab® BioaffyTM CDs with a comparison of column profiles, accuracy, precision and sensitivity. For each assay the best suited CD type was suggested together with possible upper limit of quantification (ULOQ) and lower limit of quantification (LLOQ) within the estimated detection range. The results indicate that the CHO Annexin A5 assay has a detection range extending from 1500 ng/ml to 2.1 ng/ml, with possible ULOQ at 1000 ng/ml and LLOQ at 3.2ng/ml using the BioaffyTM 4000 HC CD. The CHO Clusterin assay has a detection range extending from 1500 ng/ml to 0.4 ng/ml, with possible ULOQ at 1000 ng/ml and LLOQ at 0.7 ng/ml using the BioaffyTM 4000 HC CD. The CHO Nidogen-1 assay has a detection range extending from 1500 ng/ml to 0.1 ng/ml, with ULOQ at 1000 ng/ml and LLOQ at 0.2 ng/ml using the BioaffyTM1000 CD.

L'application d'un temps de maintien, même de faible durée, lors d'un chargement cyclique, modifie de façon très sensible à la fois le comportement contrainte-déformation et le nombre de cycles à amorçage dans l'alliage base titane TI-6242. Ceci est lié à un régime de fluage cyclique, conduisant à de la déformation progressive d'une part, et à une forte interaction fatigue-temps de maintien pour ce qui concerne le nombre de cycles à amorçage. Les différents phénomènes sont pour le moment assez mal analysés, si bien qu'il n'est pas possible d'effectuer une conception optimale des pièces, de larges marges de sécurité étant nécessaires. Le but du travail est de mieux comprendre les mécanismes locaux qui régissent le comportement et l'amorçage des fissures, dans le but de suggérer des microstructures optimales, et de calibrer des modèles macroscopiques utilisables en bureau d'études. En s'appuyant sur une base expérimentale fournie par Snecma et l'ENSMA, une approche multiéchelles a été mise en place pour représenter les hétérogénéités locales qui ont un rôle significatif sur les comportements observés. Dans les calculs des microstructures, faisant intervenir une étape d'évaluation statistique, on se focalise sur la représentation explicite des ”plumes”, grains de taille exceptionnelle, qui sont à l'origine des premières microfissures en raison du contraste cristallin qu'ils introduisent avec l'environnement. Une revue des différentes configurations de plumes, afin de retenir celles qui sont le plus critique, a été établie. Cette analyse a permis de mettre en évidence la présence de plumes simples, doubles ou triples, les domaines se présentant sous formes de bandes. Les configurations à étudier comportent comme paramètres critiques l'orientation géométrique de la bande par rapport à la direction du chargement macroscopique, mais surtout l'orientation cristallographique au sein de cette (ces) bande(s). Des calculs systématiques ont été effectués afin de mener une étude statistique et de déterminer les configurations les plus sensibles. / The application of a dwell period, even of short length, during a cyclic loading, simultaneously changes the stress-strain behaviour and the number of cycles to failure in a very sensitive way. This phenomenon is connected to a cyclic creep regime, generating progressive deformation, and to a strong interaction between the fatigue process and dwell periods for the number of cycles to failure. All these phenomena are poorly analysed nowadays, so that engineers hardly perform optimal design of the components, since large security margins are necessary. The aim of the work is to better understand the local mechanisms which govern both behaviour and crack initiation, having in view optimal microstructures, and to calibrate manageable macroscopic models for the design department. Using an experimental data set given by Snecma and ENSMA, a multiscale approach has been developed to represent the local heterogeneities that play a significant role on observed behaviour. In the calculations of microstructures that are performed for a statistical evaluation, the focus is made on the explicit representation of the so called "plumes", that are grains of exceptional size, which are at the origin of the first microcracks due to crystal contrast they introduce with the environment. A review of various "plume" configurations is made, in order to investigate the most critical ones. This analysis allowed to shed the light on the presence of simple, double or triple "plumes", the domains being in band shapes. The critical parameters are the geometric arrangement of the band with respect to the direction of the macroscopic loading, but essentially the crystal orientation within this (these) band(s). Systematic calculations were carried out in order to do a statistical study and to determine the most critical configurations.

Dans le cadre de cette thèse, nous nous sommes intéressés à la caractérisation des mécanismes de déformation et de leurs interactions pour un zinc polycristallin pur, sous les conditions de chargement complexe et local qui caractérisent l'essai de nanoindentation. En effet, l'interaction des différents mécanismes mis en jeu a généralement été étudiée sur la base de sollicitations dites simples, telles que les essais de traction uniaxiale, biaxiale… Sous l'action d'un chargement uniforme, la prépondérance d'un système particulier sera conditionnée par l'orientation du cristal et par le sens du chargement par rapport à l'axe sénaire. La situation peut être rendue plus complexe dans le cas d'un chargement non simple, comme c'est le cas de l'essai d'indentation. Nous avons réalisé des essais de nanoindentation sur des grains de différentes orientations cristallographiques (mesurées par EBSD), et les résultats obtenus en termes de courbes "charge-profondeur de pénétration" et topographie des empreintes résiduelles ont été analysés. La complexité de l'état de contrainte qui se développe dans le matériau dépend des caractéristiques géométriques de l'indenteur et des orientations cristallographiques en présence, ce qui peut donner lieu à diverses interactions entre les modes de déformation. Ces interactions impacteront directement l'écoulement plastique local du matériau, et par voie de conséquence les propriétés mécaniques macroscopiques du matériau. En adoptant une loi de comportement en plasticité cristalline, nous avons ensuite procédé à la détermination des cissions résolues critiques et des paramètres d'écrouissage pour les différents mécanismes observés. Cette détermination s'est basée sur la résolution d'un problème inverse, au cours duquel nous avons couplé la simulation numérique 3D de l'essai de nanoindentation à l'identification des paramètres de la loi de comportement au moyen d'algorithmes génétiques. La confrontation des résultats expérimentaux et numériques en termes de courbes "charge-profondeur de pénétration" et profils de déformation montrent la bonne adéquation entre les données expérimentales et le modèle identifié. Les résultats obtenus ont ainsi permis de caractériser les mécanismes de déformation observés, et de proposer des perspectives à ce travail. / Within the scope of this thesis, we focused on the characterization of deformation mechanisms and their interactions for pure polycrystalline zinc under complex and local loading conditions such that those involved in a nanoindentation test. Indeed, the interaction between the different mechanisms involved has generally been studied on the basis of so-called simple tests, such as uniaxial or biaxial tensile tests ... Given uniform loading conditions, the predominance of a given deformation system depends on the crystal orientation and the loading direction relative to the crystal c-axis. The situation may be further complicated in case of a complex stress state, as it is the case of the indentation test. We performed nanoindentation tests on grains of different crystallographic orientations (measured by EBSD) and the results (curves "load-penetration depth" and topography of residual imprints) were analyzed. The complexity of the stress state that develops underneath the indenter depends on both the geometrical characteristics of the latter and the crystallographic orientations of the grains, which can give rise to different interactions between the deformation modes. Those interactions will directly affect the local plastic flow, and thus the mechanical properties of the macroscopic material.By using a crystal plasticity model, we have then determined the critical resolved shear stresses and hardening parameters for the observed deformation mechanisms. This determination is based on the solution of an inverse problem, in which we have coupled 3D numerical simulations of the nanoindentation test to genetic algorithms to solve an optimization problem. Comparison between experimental and numerical results in terms of "load-penetration depth" curves and penetration depth profiles show a good agreement between the experimental data and the identified model. The results enabled to characterize the observed deformation mechanisms, and to provide perspectives to this work.