Dissertations / Theses on the topic 'Self-assembly systems'
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Fox, Michael Jacob. "Stochastic self-assembly." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34741.
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We present methods for distributed self-assembly that utilize simple rule-of-thumb control and communication schemes providing probabilistic performance guarantees. These methods represents a staunch departure from existing approaches that require more sophisticated control and communication, but provide deterministic guarantees. In particular, we show that even under severe communication restrictions, any assembly described by an acyclic weighted graph can be assembled with a rule set that is linear in the number of nodes contained in the desired assembly graph. We introduce the concept of stochastic
stability to the self-assembly problem and show that stochastic stability of desirable configurations can be exploited to provide probabilistic performance guarantees for the process. Relaxation of the communication restrictions allows simple approaches giving deterministic guarantees. We establish a clear relationship between availability of communication and convergence properties. We consider Self-assembly tasks for the cases of many and few
agents as well as large and small assembly goals. We analyze sensitivity of the presented process to communication errors as well as ill-intentioned agents. We discuss convergence rates of the presented process and directions for improving them.
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Razali, Azaima. "Self assembly in gel systems." Thesis, University of Bristol, 2018. http://hdl.handle.net/1983/77bc44c6-4aed-4548-90f6-4c2f6975e522.
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In this work we have studied the structural evolution of colloid polymer system reaching equilibrium ordered states. Throughout the work in this thesis, confocal microscopy was primarily used to capture the local structural changes. We employed the depletion mechanism from the addition of nonadsorbing polymer to colloidal dispersion in order to obtain short ranged attractive systems. The changes of local structures towards crystallisation in the colloid polymer systems are analysed using topological cluster classification (TCC), common neighbour analysis (CNA) and bond order parameter ψ6. Initial work studies the ageing of gels with different interaction strengths in experiment and simulation. Structural analysis of the gels shows significant similarity between experiment and simulation. In both, we find crystallisation in gels with intermediate interaction strength and formation of five-fold symmetry clusters in gels with higher interaction strengths. Then we examine the effects of confinement to the sedimentation of colloids and gels. We find that gelation enhances sedimentation of colloids whereas there is no sedimentation in a same system without polymer. The structural analysis of the simulation results show that the local structural changes is not related to sedimentation. By manipulating the polymer response to temperature, we change the interaction strength in the colloid polymer system in order to obtain better crystallisation. This work is based on the idea from simulation work [1], where tuning the interaction strengths during self assembly leads to better and larger ordered structures. However, contrary to the simulation results, we find that tuning the interaction strengths result to disruption to the crystallisation pathway thus more disordered structures is formed.
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Fejer, Szilard. "Self-assembly in complex systems." Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611771.
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Kwiecinski, James Andrew. "Self-assembly in mechanical systems." Thesis, University of Oxford, 2018. http://ora.ox.ac.uk/objects/uuid:a3b521ad-be4a-4152-aaa6-f9a002060c48.
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Inspired by biological membrane shaping in the cell through means of curvature-inducing proteins, we investigate the interplay between membrane curvature and the distribution and movement of shape-inducing objects which are free to move as a consequence of the underlying shape. We initially study the self-assembly of a filament, taken as a proxy for the cross-section of a biomembrane, which is primarily driven by the chemical kinetics of attaching proteins and find that, under certain mechanical stiffness regimes of the attaching proteins, pattern formation occurs. Regions of high and low protein concentration form before spatially uniform filament shapes are obtained by means of protein adhesion and movement governed by diffusion and local curvature-seeking. However, noting that the curvature-mediated protein movement on membranes has been biologically observed to be long-range, we next study the self-assembly of embedded inclusions on a membrane as a result of the underlying geometry. We first derive an interaction law for the shape-mediated interaction of inclusions which break symmetry and find that there is a finite equilibrium distance to which the inclusions will aggregate. We derive corresponding equations of motion which describe this curvature-mediated aggregation mechanism and, using this framework, we investigate some of the properties of these self-assembled configurations, including their energy, stability, and their collective elastic behavior. Lastly, we consider the interaction energies of embedded inclusions on a periodic domain and determine that this mechanism may explain computational results of how proteins form rings to promote tubulation on cylindrical membranes.
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Antzoulatos, Nikolas. "Towards self-adaptable intelligent assembly systems." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/39583/.
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Currently, European small and medium-sized enterprises (SMEs) are experiencing increasing pressure to provide high quality goods with customised features while at the same time remain cost effective and competitive in the global market. In the future, manufacturing systems need to be able to cope with constantly changing market requirements. Consequently, there is a need to develop the research foundations for a new generation of manufacturing systems composed of intelligent autonomous entities which are able to reconfigure themselves and to adapt their performance as a result of product and environmental changes. The research described in this thesis addresses the issue by developing three distinctive elements of an adaptation framework for next-generation manufacturing systems. The first element is a capability-based data model for the representation of manufacturing resources to enable self-awareness. The model captures the resources’ life cycle and performance indicators to provide information about the resources’ condition. The second element is a multi-agent architecture for plug and produce and the reconfiguration of manufacturing systems. The resource data model is utilised by the agent society, which is able to instantiate a model to represent a physical resource in the virtual agent society. The shift to the virtual environment enables a communication infrastructure for heterogeneous resources and the application of the digital twin concept. The agent architecture applies negotiation techniques to establish a plan for system adaptation. The third element is a methodology for automated experience-based manufacturing system adaptation. The adaptation methodology is based on previous runtime experience instances to generate adaptation knowledge. The information generated is applied to the current context and part of the agent negotiation which is dynamically executed in case of a disturbance. Collectively, these three elements significantly increase the flexibility and reconfigurability of a manufacturing system reducing the time required for integration and maintenance of complex systems on demand, improving their effectiveness. The developed framework is implemented and evaluated experimentally on a physical, industrial standard demonstrator and using a virtual simulation model. The experimental results confirm a significant step towards new solutions for the deployment of self-adaptable intelligent manufacturing systems.
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Terrazas, Angulo German. "Automated evolutionary design of self-assembly and self-organising systems." Thesis, University of Nottingham, 2009. http://eprints.nottingham.ac.uk/10648/.
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Self-assembly and self-organisation are natural construction processes where the spontaneous formation of aggregates emerges throughout the progressive interplay of local interactions among its constituents. Made upon cooperative self-reliant components, self-assembly and self-organising systems are seen as distributed, not necessarily synchronous, autopoietic mechanisms for the bottom-up fabrication of supra-structures. The systematic understanding of how nature endows these autonomous components with sufficient ''intelligence'' to combine themselves to form useful aggregates brings challenging questions to science, answers to which have many potential applications in matters of life and technological advances. It is for this reason that the investigation to be presented along this thesis focuses on the automated design of self-assembly and self-organising systems by means of artificial evolution. Towards this goal, this dissertation embodies research on evolutionary algorithms applied to the parameters design of a computational model of self-organisation and the components design of a computational model of self-assembly. In addition, an analytical assessment combining correlation metrics and clustering, as well as the exploration of emergent patterns of cooperativity and the measurement of activity across evolution, is made. The results support the research hypothesis that an adaptive process such as artificial evolution is indeed a suitable strategy for the automated design of self-assembly and self-organising systems where local interactions, homogeneity and both stochastic and discrete models of execution play a crucial role in emergent complex structures.
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Xiong, Xiaorong. "Controlled multi-batch self-assembly of micro devices /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/5917.
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Puntambekar, Smita. "Molecular self assembly in fluorocarbon surfactant/water systems." Thesis, University of Central Lancashire, 2000. http://clok.uclan.ac.uk/20906/.
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The work presented is a continuation of the study of a homologous series of tetrabutylammonium perfluoroalkylcarboxylate surfactants in water. These systems showed phase behaviour uncharacteristic of ionic perfluorocarbon surfactant systems in that they exhibit a clouding phenomenon with increasing temperature. This behaviour was ascribed to the tight association of the large, hydrophobic counterions with the poiar head group region. In this study a series of perfluorocarbon surfactants have been synthesised in which the hycirophobicity of the counterion is varied. The counterion is W (CH2CH2CH2CH3)(CH3) 41 whilst the surfactant ion remains unchanged throughout the series as periluorodecanoate. The number of butyl chains. 'n' controls the hydrophobicity of the counterion and, in these experiments, n = 4, 2, 1 and 0. The phase diagrams and the detailed phase structures have been investigated using optical polarising microscopy, 2H NMR spectroscopy and small angle x-ray scattering. As n decreases, the phase diagrams change, recovering the "generic" phase behaviour more usual for a perfluorocarbon surfactant - water system. X-ray measurements show that in the n = 4 (tetrabutylammonium perfluorodecanoate) system, all the phases (both liquid crystalline and non-liquid crystalline) have uniform mean interfacial curvature. The phases observed are L 1 (vesicles), L. and L 2. With decreasing counterion hydrophobicity, the population of counterions associated with the interface decreases, introducing greater curvature into the system. The mean curvature of the phase structures also becomes nonuniform. For n = 0 (tetramethylammonium perfluorodecarioate) no classical mesophases are observed. Much of the liquid crystalline region is taken up with a random mesh intermediate phase, Mh 1 (0) and an extensive rhombohedral mesh intermediate phase, Mh1 (R3 m). Phase behaviour intermediate between the two extremes is observed at n = 1 (butyltrimethylammonium perfluorodecanoate). In this system, the clouding phenomenon is not observed but there is a two phase region of L 1 + L. at low concentration and high temperatures. The phase structures also possess uniform mean curvature. In keeping with the less hydrophobic systems, the L. phase is less temperature sensitive at high concentrations. This work has shown that the but'l groups of the counterion are, in part, responsible for the unusual phase behaviour observed in the TBA surfactants. The hydrophobic nature of the counterion has a major impact on the structures formed even at high dilution. This nature probably drives the counterion to the interface which affects the type of mesophase formed at higher concentrations and also determines its stability with respect to temperature and concentration.
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Brust, Mathias. "The self-assembly of nanostructured gold-dithiol systems." Thesis, University of Liverpool, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260334.
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Branda, Neil R. (Neil Robin). "Synthetic recognition systems : self-assembly and metal chelation." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/17367.
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Spiteri, Ludovic. "Self-assembly of dipolar particles." Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0261/document.
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Cette thèse couvre l'auto-assemblage de particules dipolaires (magnétiques/électriques). Ces systèmes sont abondants en physique de la matière condensée (molécules et nanoparticules magnétiques, particules colloïdales magnétiques, bactérie magnétotactique, etc.). Sur un plan fondamental, ils représentent un défi important en raison de l'anisotropie et de la longue portée de l'interaction de paire. Le principal objectif de ce travail de recherche est de prédire les microstructures de ces systèmes en tenant compte de façon adéquate de l'interaction complexe dipôle-dipôle ainsi que des effets stériques et ceux dus à un éventuel confinement. Comprendre et revisiter les interactions de filaments dipolaires tels que des aiguilles et des chaînes faites de billes dipolaires est une première étape importante de cette thèse. En effet, les chaînes sont les constituants élémentaires de nombreux systèmes dipolaires, notamment sous l'effet d'un champ magnétique extérieur appliqué. Ensuite, l'agrégation colonnaire des chaînes dipolaires est examinée, ce qui conduit aussi naturellement à l'étude des cristaux dipolaires massifs où une nouvelle phase est découverte. Le cas plus générique des chaînes hélicoïdales est discuté en considérant les situations limites que sont les chaînes linéaires droites et en zigzag. L'association des chaînes dipolaires, dans le cas bidimensionnel, forme des rubans, puis une monocouche avec un réseau hexagonal. La réponse non triviale d'un tel réseau à un champ magnétique perpendiculaire imposé est aussi étudiée. Il est démontré qu'un réseau rhombique peut être induit de cette façon. Finalement, la sédimentation de particules paramagnétiques dans une monocouche inclinée en présence d'un champ magnétique est explorée via une étude mêlant expériences, théorie et simulations. L'ordre induit par gravité s'avère être une voie prometteuse pour l'élaboration contrôlée de réseaux bidimensionnelsThis thesis covers the self-assembly of dipolar (magnetic/dielectric) particles. These systems are abundant in condensed matter physics (magnetic molecules and nanoparticles, magnetic colloidal particles, magnetotactic bacteria, etc). They also represent a fundamental challenge owing to the both long range and anisotropic nature of the pair interaction. The main objective of this research work is to predict the microstructures of these systems by properly handling the intricate dipole-dipole interaction combined with steric and possibly confinement effects. Understanding and revisiting the interaction of dipolar filaments such as needles or chains made up of dipolar beads is a first important achievement in this thesis. Indeed, the chains are the fundamental building blocks of many dipolar systems especially under applied external magnetic field. Then, the columnar aggregation of dipolar chains is investigated which naturally leads to the study of the bulk dipolar crystals. A new phase is discovered there. The more generic case of helical chains is discussed by considering limiting situations such as straight linear chains and zigzag chains. The association of dipolar chains in two-dimensions forms ribbons then a monolayer with triangular lattice symmetry. The interesting response of such a layer to an imposed perpendicular magnetic is addressed as well. It is demonstrated that rhombicity can be induced that way. Finally, sedimenting paramagnetic particles in a tilted monolayer in presence of a magnetic field are investigated by experiments, theory and simulations. The gravity-mediated ordering is found to be a promising route to elaborate tailored two-dimensional patterns
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Campbell, V. E. "Subcomponent self-assembly : from topological complexity to dynamic systems." Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.597267.
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This thesis initially (Chapter 1) reviews some of the background literature for constitutional dynamic chemistry (supramolecular and dynamic covalent chemistry), templated self-assembly, subcomponent self-assembly, oligoamide foldamers, and systems chemistry. The motivation in bringing these areas together was the construction of both topologically complex architectures (such as helicates, macrocycles, catenanes, knots and large proteomorphous entities) and complex dynamic self-assembling systems. Chapter 2 describes the synthesis of homometallic and heterometallic structures (helicates and a pincer-like complex) via subcomponent self-assembly. These helicates readily participated in a dynamic system of transformations where the limited addition of a building block imposed the subcomponents to preferentially assemble into well-defined predicted structures. In Chapter 3, the construction of an atypical dicopper(I) helical macrocycle and catenane were shown. This macrocycle participated in a series of imine exchange reactions mediated by electronic effects, entropic effects and the coordinative preferences of copper(I) ions. The thermodynamic stability of this macrocycle was extrapolated through van’t Hoff analysis of an imine exchange reaction. Chapter 4 describes the synthesis of large proteomorphous objects. Amine-functionalized aromatic oligoamide foldamers were employed as building blocks in subcomponent self-assembly reactions. It was possible to assemble helices at angles of 90° and 180°, and to assemble up to four helices around copper(I) ions, synthesising large tertiary structures whose molecular weights approaches those of proteins. Chapter 5 outlines some of latest preliminary results towards more complex architectures and systems.
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Karpenko, Daria. "Active Tile Self-assembly and Simulations of Computational Systems." Scholar Commons, 2015. https://scholarcommons.usf.edu/etd/5519.
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Algorithmic self-assembly has been an active area of research at the intersection of computer science, chemistry, and mathematics for almost two decades now, motivated by the natural self-assembly mechanism found in DNA and driven by the desire for precise control of nanoscale material manufacture and for the development of nanocomputing and nanorobotics. At the theoretical core of this research is the Abstract Tile Assembly Model (aTAM), the original abstract model of DNA tile self-assembly. Recent advancements in DNA nanotechnology have been made in developing strand displacement mechanisms that could allow DNA tiles to modify themselves during the assembly process by opening or closing certain binding sites, introducing new dynamics into tile self-assembly.
We focus on one way of incorporating such signaling mechanisms for binding site activation and deactivation into the theoretical model of tile self-assembly by extending the aTAM to create the Active aTAM. We give appropriate definitions first for incorporating activation signals and then for incorporating deactivation signals and tile detachment into the aTAM. We then give a comparison of Active aTAM to related models, such as the STAM, and take a look at some theoretical results.
The goal of the work presented here is to define and demonstrate the power of the Active aTAM with and without deactivation. To this end, we provide four constructions of temperature 1 (also known as "non-cooperative") active tile assembly systems that can simulate other computational systems. The first construction concerns the simulation of an arbitrary temperature 2 (also known as "cooperative") standard aTAM system in the sense of producing equivalent structures with a scaling factor of 2 in each dimension; the second construction generates the time history of a given 1D cellular automaton. The third and fourth constructions make use of tile detachment in order to dynamically simulate arbitrary 1D and 2D cellular automata with assemblies that record only the current state updates and not the entire computational history of the specified automaton.
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Cooper, Christopher G. F. "Self-assembled systems for molecular device applications." Link to electronic thesis, 2004. http://www.wpi.edu/Pubs/ETD/Available/etd-0430104-152257/.
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Ferreira, Pedro. "An agent-based self-configuration methodology for modular assembly systems." Thesis, University of Nottingham, 2011. http://eprints.nottingham.ac.uk/12325/.
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Assembly systems today are exposed to market trends that have become increasingly more dynamic and unpredictable, requiring product changes and adjustments which emphasise de need for more flexible systems. The requirement for increased responsiveness has led to the development of new modular concepts which provide the bases for achieving higher system adaptability through increased component/module interchangeability and reusability. The modularization of physical and control infrastructure does, however, only address one aspect of the issue and there is still a lack of appropriate tools and methods to support the rapid configuration and reconfiguration of such systems for changing sets of requirements. This work proposes a new distributed methodology for the configuration and reconfiguration of Modular Assembly Systems (MAS) through the use of agent technology. The new methodology defines a comprehensive model for the structured description of the MAS requirements, equipment modules and the configuration results. This thesis proposes a new agent architecture for the self-configuration of equipment modules into systems based on a given set of requirements, as the core of the self-configuration methodology. This architecture introduces the overall behaviour of the methodology through the definition of agent types, roles and overall interactions. Furthermore this work describes the development of the specific models and methods for the local behaviour of each agent. These enable the actual decision making method for the agents to achieve configuration solutions. This work also reports on a new methodology for the early performance simulation of MAS characteristics that can be used in conjunction with the configuration methodology.
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Gazzaz, Hanna Asaad. "Kinetics of metal ion complex formation in self-assembly systems." Thesis, University of East Anglia, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365019.
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Greco, E. "Synthesis of self-assembly systems with multiple hydrogen bonding interactions." Thesis, University College London (University of London), 2009. http://discovery.ucl.ac.uk/17980/.
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Supramolecular chemistry and the development of “supramolecular polymers” are of direct relevance to materials science. Defined as “chemistry beyond the molecule, the chemistry of tailor-shaped intermolecular interactions”, supramolecular chemistry is concerned with preparing assemblies of molecules using a combination of secondary chemical interactions rather than covalent bonding. The comparatively simple molecules used in these assemblies are driven to spontaneously self-assemble, and then hold together, via such non-covalent interactions as hydrogen bonds, metal coordination sites and Van der Waals forces. In order to assess whether the functionalization of cytosine with longer alkyl chains affects its properties, 1-methyl cytosine was synthesised as a ureidopyrimidinone (UPy) mimic for incorporation into arrays. The synthesis of further compounds functionalized at N-1 of the cytosine motif has been achieved and is fully described. In order to investigate the strength of the AADD array formation, a 5-fluoromethyl cytosine motif has been studied. Following previous work, the use of quadruple hydrogen bonded units has been investigated and UPy and cytosine units incorporating OH and NH2 terminated polymers have been studied. Subsequently, the synthesis of energetic and non-energetic supramolecular polymers has been achieved. In order to investigate the potentially different physical properties of the telechelic diamine polymers other polymers were synthesized containing a double urea unit. With the purpose of synthesizing an energetic H-bonded polymer the functionalization at N-1 position on cytosine unit with a dioxolane moiety has been examined. Furthermore, a new strategy to difunctionalised cytosine molecules has been explored with the synthesis of and an amino acid derivative. In addition, further investigations into the functionalization at the N-1 position on cytosine via click chemistries have been studied for the adjustment of polymer properties and to synthesize a bifunctional system possessing units at each end. In order to establish functional applications of our materials, large scale syntheses of mono urea polymers have been obtained and properties of the materials fully examined.
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Rosa, Rogério Paulo Guerreiro. "Assessing self-organization and emergence in Evolvable Assembly Systems (EAS)." Master's thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/10990.
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Dissertação para obtenção do Grau de Mestre em
Engenharia Electrotécnica e de ComputadoresThere is a growing interest from industry in the applications of distributed IT. Currently, most modern plants use distributed controllers either to control production processes, monitor them or both. Despite the efforts on the last years to improve the implementation of the new manufacturing paradigms, the industry is still mainly using traditional controllers. Now, more than ever, with an economic crisis the costumers are searching for cheap and customized products, which represents a great opportunity for the new paradigms to claim their space in the market. Most of the research on distributed manufacturing is regarding the control and communication infrastructure. They are key aspects for self-organization and there is a lack of study on the metrics that regulate the self-organization and autonomous response of modern production paradigms. This thesis presents a probabilistic framework that promotes self-organization on a multiagent system based on a new manufacturing concept, the Evolvable Assembly Systems/Evolvable Production Systems. A methodology is proposed to assess the impact of self-organization on the system behavior, by the application of the probabilistic framework that has the dual purpose of controlling and explaining the system dynamics. The probabilistic framework shows the likelihood of some resources being allocated to the production process. This information is constantly updated and exchanged by the agents that compose the system. The emergent effect of this self-organization dynamic is an even load balancing across the system without any centralized controller. The target systems of this work are therefore small systems with small production batches but with a high variability of production conditions and products. The agents that compose the system originated in the agent based architecture of the FP7-IDEAS proejct. This work has extended these agents and the outcome has been tested in the IDEAS demonstrators, as the changes have been incorporated in the latest version of the architecture, and in a simulation and more controlled environment were the proposed metric and its influence were assessed.
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Phoomboplab, Tirawat. "Self-resilient production systems : framework for design synthesis of multi-station assembly systems." Thesis, University of Warwick, 2012. http://wrap.warwick.ac.uk/59325/.
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Product design changes are inevitable in the current trend of time-based competition where product models such as automotive bodies and aircraft fuselages are frequently upgraded and cause assembly process design changes. In recent years, several studies in engineering change management and reconfigurable systems have been conducted to address the challenges of frequent product and process design changes. However, the results of these studies are limited in their applications due to shortcomings in three aspects which are: (i) They rely heavily on past records which might only be a few relevant cases and insufficient to perform a reliable analysis; (ii) They focus mainly on managing design changes in product architecture instead of both product and process architecture; and (iii) They consider design changes at a station-level instead of a multistation level. To address the aforementioned challenges, this thesis proposes three interrelated research areas to simulate the design adjustments of the existing process architecture. These research areas involve: (i) the methodologies to model the existing process architecture design in order to use the developed models as assembly response functions for assessing Key Performance Indices (KPIs); (ii) the KPIs to assess quality, cost, and design complexity of the existing process architecture design which are used when making decisions to change the existing process architecture design; and (iii) the methodology to change the process architecture design to new optimal design solutions at a multi-station level. In the first research area, the methodology in modeling the functional dependence of process variables within the process architecture design are presented as well as the relations from process variables and product architecture design. To understand the engineering change propagation chain among process variables within the process architecture design, a functional dependence model is introduced to represent the design dependency among process variables by cascading relationships from customer requirements, product architecture, process architecture, and design tasks to optimise process variable design. This model is used to estimate the level of process variable design change propagation in the existing process architecture design Next, process yield, cost, and complexity indices are introduced and used as KPIs in this thesis to measure product quality, cost in changing the current process design, and dependency of process variables (i.e, change propagation), respectively. The process yield and complexity indices are obtained by using the Stream-of-Variation (SOVA) model and functional dependence model, respectively. The costing KPI is obtained by determining the cost in optimizing tolerances of process variables. The implication of the costing KPI on the overall cost in changing process architecture design is also discussed. These three comprehensive indices are used to support decision-making when redesigning the existing process architecture. Finally, the framework driven by functional optimisation is proposed to adjust the existing process architecture to meet the engineering change requirements. The framework provides a platform to integrate and analyze several individual design synthesis tasks which are necessary to optimise the multi-stage assembly processes such as tolerance of process variables, fixture layouts, or part-to-part joints. The developed framework based on transversal of hypergraph and task connectivity matrix which lead to the optimal sequence of these design tasks. In order to enhance visibility on the dependencies and hierarchy of design tasks, Design Structure Matrix and Task Flow Chain are also adopted. Three scenarios of engineering changes in industrial automotive design are used to illustrate the application of the proposed redesign methodology. The thesis concludes that it is not necessary to optimise all functional designs of process variables to accommodate the engineering changes. The selection of only relevant functional designs is sufficient, but the design optimisation of the process variables has to be conducted at the system level with consideration of dependency between selected functional designs.
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Wood, Kris Cameron. "Nanostructured gene and drug delivery systems based on molecular self-assembly." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/39350.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2007.Includes bibliographical references.
Molecular self-assembly describes the assembly of molecular components into complex, supramolecular structures governed by weak, non-covalent interactions. In recent years, molecular self-assembly has been used extensively as a means of creating materials and devices with well-controlled, nanometer-scale architectural features. In this thesis, molecular self-assembly is used as a tool for the fabrication of both gene and drug delivery systems which, by virtue of their well-controlled architectural features, possess advantageous properties relative to traditional materials used in these applications. The first part of this thesis describes the solution-phase self-assembly of a new family of linear-dendritic "hybrid" polymers with plasmid DNA for applications in gene therapy. It begins with an overview of the design of next-generation, non-viral gene delivery systems and continues through the synthesis and validation of hybrid polymer systems, which possess modular functionalities for DNA binding, endosomal escape, steric stabilization, and tissue targeting. This part of the thesis concludes with applications of these systems to two areas of clinical interest: DNA vaccination and tumor targeted gene therapy.
(cont.) The second part of this thesis describes the directed self-assembly of polymeric thin films which are capable of degrading in response to either passive or active stimuli to release their contents. It begins with a description of passive release thin films which degrade by basic hydrolysis to release precise quantities of model drug compounds. These systems can be engineered to release their contents on time scales ranging from hours to weeks and can also be designed to release multiple drugs either in series or in parallel. Later, field-activated thin films which release their contents in response to an external, electrical stimulus are described and characterized in detail. Together, these approaches combine rapid and inexpensive processing, the ability to conformally coat any surface regardless of composition, size, or shape, and the ability to release multi-drug or multi-dose schedules, and as such they may find applications in a range of areas.
by Kris Cameron Wood.
Ph.D.
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Steinbach, Gabi, Dennis Nissen, Manfred Albrecht, Ekaterina V. Novak, Pedro A. Sánchez, Sofia S. Kantorovich, Sibylle Gemming, and Artur Erbe. "Bistable self-assembly in homogeneous colloidal systems for flexible modular architectures." Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-202517.
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This paper presents a homogeneous system of magnetic colloidal particles that self-assembles via two structural patterns of different symmetry. Based on a qualitative comparison between a real magnetic particles system, analytical calculations and molecular dynamics simulations, it is shown that bistability can be achieved by a proper tailoring of an anisotropic magnetization distribution inside the particles. The presented bistability opens new possibilities to form two-dimensionally extended and flexible structures where the connectivity between the particles can be changed in vivoDieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
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Wu, Yuchao. "Cucurbit[n]uril-based colloidal self-assembly in hybrid polymeric systems." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/270021.
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Supramolecular interactions are of great importance in the fabrication of new functional materials. In particular, colloidal assembly via supramolecular pathway has contributed to numerous innovations in material chemistry, on account of its specific, directional and dynamic non-covalent interactions. By taking advantage of the non-covalent supramolecular interactions, tailored complementary colloidal building blocks which are normally incompatible with each other could be integrated interdependently, forming novel hybrid materials with emerging properties. This thesis mainly focuses on the design, preparation and characterization of novel colloidal assemblies based on cucurbit[n]urils host-guest interactions, including hybrid ‘raspberry-like’ colloids, catalytic polymeric nanocomposites, advanced structured colloids, and supramolecular polymer colloidal hydrogel.
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Ge, Chen. "Nanopatterning on metallic and ceramic systems via self-assembly and polymer system via replica molding." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1461180232.
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Bhise, Anil Dnyanoba. "A biomimetic approach for synthesizing artificial light-harvesting systems using self-assembly." Karlsruhe : FZKA, 2004. http://bibliothek.fzk.de/zb/berichte/FZKA7174.pdf.
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Bhise, Anil Dnyanoba. "A biomimetic approach for synthesizing artificial light-harvesting systems using self-assembly /." Karlsruhe : Forschungszentrum, 2005. http://www.gbv.de/dms/bs/toc/503994367.pdf.
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Univ., Diss.--Karlsruhe, 2005.Auch als elektronische Ressource vorh. Literaturverz. S. 126 - 133. Unterschiede zwischen dem gedruckten Dokument und der elektronischen Ressource können nicht ausgeschlossen werden. Zsfassung in dt. Sprache.
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Hong, Young Ki. "Surface tension self-assembly for three dimensional micro-opto-electro-mechanical systems." Thesis, Imperial College London, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.429321.
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Chen, Chao. "Self-assembly studies of hybrid nanoparticle-protein cage systems and icosahedral viruses." [Bloomington, Ind.] : Indiana University, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3331353.
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Thesis (Ph.D.)--Indiana University, Dept. of Chemistry, 2008.Title from PDF t.p. (viewed on Jul 27, 2009). Source: Dissertation Abstracts International, Volume: 69-11, Section: B, page: 6818. Adviser: Bogdan Dragnea.
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Serpe, Michael Joseph. "Self-Assembly of Poly(N-isopropylacrylamide) Microgel Thin Films." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4806.
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The assembly of poly(N-isopropylacrylamide-co-acrylic acid) (pNIPAm-co-AAc) microgel thin films into disordered and ordered arrays was investigated. Disordered pNIPAm-co-AAc microgel arrays were assembled based on electrostatic attractions between polyanionic pNIPAm-co-AAc microgels and polycationic poly(allylamine hydrochloride) (PAH). These interactions were studied in solution and subsequently used to assemble thin films following a Layer-by-Layer assembly protocol. Thin films were assembled as a function of pNIPAm-co-AAc microgel solution temperature and the resultant film thermoresponsivity characterized as a function of microgel layer number and pH. The response of assembled thin films to pH 3.0 and 6.5 exposure was then characterized by quartz crystal impedance and surface plasmon resonance spectroscopy, which showed that the thin film solvation was highly dependent on the pH of the solution it was in. Assembled thin films were also shown to be useful as controlled drug delivery platforms, where it was found that small molecules could be released from the films in a temperature regulated fashion. Microgel thin films also exhibited unique optical properties and were used as microlens arrays, which were able to focus pattern in air as well as in solution and had focal lengths that could be tuned in response to pH and temperature changes. Ordered microgel arrays were assembled following a thermal annealing process, in order to make light diffracting materials. These ordered arrays were photopolymerized and exhibited temperature dependent Bragg diffraction properties.
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McKnight, Patrick T. "Finite Element Analysis of Thermoelectric Systems with Applications in Self Assembly and Haptics." Scholar Commons, 2010. http://scholarcommons.usf.edu/etd/3630.
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Micro-scale self assembly is an attractive method for manufacturing sub-millimeter sized thermoelectric device parts. Challenges controlling assembly yield rates, however, have caused research to find novel ways to implement the process while still resulting in a working device. While a typical system uses single n-type and p-type material elements in series, one method used to increase the probability of a working device involves adding redundant parallel elements in clusters. The drawback to this technique is that thermal performance is affected in clusters which have missing elements. While one-dimensional modeling sufficiently describes overall performance in terms of average junction temperatures and net heat flux, it fails when a detailed thermal profile is needed for a non-homogeneous system. For this reason, a three-dimensional model was created to describe thermal performance using Ansys v12.1. From the results, local and net performance can be described to help in designing an acceptable self-assembled device.
In addition, a haptic thermal display was designed using thermoelectric elements with the intention of testing the thermal grill illusion. The display consists of 5 electrically independent rows of thermoelectric elements which are controlled using pulse width modulating direct current motor controllers.
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White, Claire Michelle. "Ruthenium polypyridyl complexes designed for the non-covalent self-assembly of supramolecular systems." Thesis, University of Bristol, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265497.
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Gray, Sarah Jane. "Dissipative particle dynamics simulations of surfactant systems : phase diagrams, phases and self-assembly." Thesis, Durham University, 2018. http://etheses.dur.ac.uk/12641/.
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Surfactants, as lyotropic liquid crystals, exhibit a whole host of ordered liquid phases, as a function of surfactant concentration, solvent identity, and any additives present. These ordered phases confer properties to the solution on a macroscopic level, and so understanding ordered phase formation is critical in predicting the physical behaviours of surfactant--containing mixtures. Typically, household cleaning products contain sufficiently low surfactant concentrations that micellar solutions form, resulting in isotropic, low viscosity liquids. However, in recent years ``single unit dose'' (SUD) products have became increasing popular. The formulation of SUDs results in high concentrations of surfactant, which can result in undesirable properties such as excessively high viscosity, turbidity, and poor product dispersal. This work aims to elucidate the nature of the ordered structures that form in these products, and understand the molecular driving factors that result in their formation. To gain an understanding of the molecular--level interactions involved in these liquid mixtures, we applied the Dissipative Particle Dynamics (DPD) simulation method. DPD is the ideal technique to study mesophase formation of these mixtures as it is exceptionally fast, allowing one to simulate on the mesoscale (the pertinent length scale for mesophase studies) while retaining detail on the order of molecular fragments. The main body of this work has been dedicated to investigating the parameterisation of DPD models in a tractable manner. We have developed a highly transferable DPD model of the most common anionic surfactants: sodium dodecylsulphate, linear alkylbenzene sulphonate, and alkylether sulphate. Our model reproduces the phase behaviour of both individual isomers and isomeric mixtures, across entire phase diagrams (with respect to concentration). Although there are some difficulties in producing chemically tractable models with DPD, once developed these models are an incredibly powerful tool in studying phase behaviour from a molecular perspective.
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Hristova, Yana Roumenova. "Subcomponent self-assembly of diverse metallo-supramolecular systems from 3,3'-bipyridine-6,6'-dicarboxaldehyde." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610122.
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Valkov, Eugene. "Design and analysis of self-assembling protein systems." Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670100.
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Al-Milaji, Karam Nashwan. "Material Interactions and Self-Assembly in Inkjet Printing." VCU Scholars Compass, 2019. https://scholarscompass.vcu.edu/etd/6053.
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Inkjet printing has attracted much attention in recent years as a versatile manufacturing tool, suitable for printing functional materials. This facile, low-cost printing technique with high throughput and accuracy is considered promising for a wide range of applications including but not limited to optical and electronic devices, sensors, solar cells, biochips, and displays. The performance of such functional devices is significantly influenced by the deposit morphology and printing resolution. Therefore, fabrication functional devices with precise footprints by inkjet printing requires deep understanding of ink properties, material interactions, and material self-assembly.
In conventional inkjet printing process, where sessile droplets are directly printed on substrates, particle depositions are usually associated with the well-known, undesirable coffee-ring effect due to the high solvent evaporation rate at the edges of the printed droplets. Such particle accumulation phenomenon in vicinity of the three-phase contact lines of sessile droplets is considered detrimental to inkjet printing applications. This study investigates the material interactions and self-assembly of colloidal inks in inkjet printing applications at different length scales. The potential of inkjet printing has been exploited through employing the dual-droplet inkjet printing of colloidal particles to investigate the self-assembly of colloidal nanoparticles at the air-liquid interface and at the three-phase contact line of sessile droplets, which provide better understanding of the particle deposition morphologies after solvent evaporation. Different from conventional inkjet printing, the dual-droplet printing involves jetting wetting droplets, containing colloidal nanoparticles dispersed in solvents with high vapor pressure, over supporting droplets composed of water only. By tuning the surface tensions and controlling the jetting parameters of the jetted droplets, monolayers with closely-packed deposition of colloidal nanoparticles are demonstrated. Various solutions are proposed to totally suppress or mitigate the coffee-ring effect in inkjet printing applications through tuning the pH value of the supporting droplets in the dual-droplet inkjet printing to control the multibody interactions (i.e., particle-particle, particle-interface, and particle-substrate interactions) or by applying magnetic field to direct the self-assembly of colloidal particles in conventional inkjet printing. In addition, the influence of various forces such as drag force, van der Waals force, electrotactic force, and capillary force on the particle deposition and assembly in vicinity of the three-phase contact line area were investigated for both the conventional and dual-droplet inkjet printing techniques.
Finally, fabrication of functional devices such as stretchable conductors have also been demonstrated by inkjet printing of silver nanowires into elastomer substrate, where the viscous liquid elastomer layer shaped the printed silver wire lines into tens of micrometers in dimeter. The silver nanowires align along the printing direction during solvent evaporation, resulting in wires with good mechanical stability and electrical performance. The printing techniques and the outcomes presented in this study can be harnessed in engineering and manufacturing a wide range of technological applications ranging from high-performance optical and electronic devices to stretchable conductors and sensors.
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Lim, Yun Fong. "Some Generalizations of Bucket Brigade Assembly Lines." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6910.
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A fascinating feature of bucket brigade assembly lines is that work load on workers is balanced spontaneously as workers follow some simple rules in the assembly process. This self-organizing
property significantly reduces the management effort on an assembly line. We generalize this idea in several directions. These include an adapted bucket brigade protocol for complex assembly networks, a generalized model that permits chaotic behavior, and a more detailed model for a flow line in which jobs arrive arbitrarily in time and are introduced into the system at several points on the line.
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Zaucha, Michael Thomas. "Biomechanics and biaxial mechanical stimulation of self-assembly tissue engineered blood vessels." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39532.
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Despite efforts by clinicians and scientists world-wide, coronary artery disease remains to be the leading cause of morbidity and mortality in industrialized nations. Development of a tissue engineered coronary by-pass graft with low thrombogenicity and immune responses, suitable mechanical properties, and a capacity to remodel to their environment could have a significant impact on the treatment of coronary artery disease. While many methods for the tissue engineering of blood vessels have been developed, one promising approach is the self-assembly method. Using autologous cells that produce an endogenous extracellular matrix (ECM), the potential for therapeutic success is high due to biocompatibility. However, despite these advantages, improvements can be made which will give the grafts an even higher rate of patency. This dissertation presents a study of the characterization of the biaxial mechanical properties of self-assembly tissue engineered blood vessels (SA-TEBV), as well as developing a framework for fabrication strategies of SA-TEBV.
Native arteries are exposed to multiaxial mechanical loads, including (a pulsatile) blood pressure that causes the vessel to cyclically distend circumferentially, blood flow that induces a shearing load along the luminal surface, and an axial extending load; the latter is relieved upon excision, causing the vessel to retract. These mechanical loads introduce intramural wall stresses and flow induced wall shear stresses that play a key role in mechano-biological signaling and tissue homeostasis. Until now, the mechanical properties of SA-TEBV have only been characterized in the circumferential direction (i.e. burst pressure and circumferential elastic modulus). The objective of this work is to characterize the biaxial mechanical properties of SA-TEBV to quantify their mechanical behavior and local intramural stresses under physiological loading. The work will show that while the global mechanical response of the SA-TEBV is similar to that of native arteries (and potentially sufficient), the local intramural stresses (using the current fabrication techniques) differ greatly from native coronary arteries. Therefore, a novel approach to fabricate the self-assembly derived tissue sheets is developed and tested which utilizes biaxial mechanical stimulation to alter the microstructure, thereby controlling their mechanical response.
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Mathews, Nithin. "Beyond self-assembly: Mergeable nervous systems, spatially targeted communication, and supervised morphogenesis for autonomous robots." Doctoral thesis, Universite Libre de Bruxelles, 2018. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/267717.
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The study of self-assembling robots represents a promising strand within the emerging field of modular robots research. Self-assembling robots have the potential to autonomously adapt their bodies to new tasks and changing environments long after their initial deployment by forming new or reorganizing existing physical connections to peer robots. In previous research, many approaches have been presented to enable self-assembling robots to form composite morphologies. Recent technological advances have also increased the number of robots able to form such morphologies by at least two orders of magnitude. However, to date, composite robot morphologies have not been able to solve real-world tasks nor have they been able to adapt to changing conditions entirely without human assistance or prior knowledge.In this thesis, we identify three reasons why self-assembling robots may not have been able to fully unleash their potential and propose appropriate solutions. First, composite morphologies are not able to show sensorimotor coordination similar to those seen in their monolithic counterparts. We propose "mergeable nervous systems" -- a novel methodology that unifies independent robotic units into a single holistic entity at the control level. Our experiments show that mergeable nervous systems can enable self-assembling robots to demonstrate feats that go beyond those seen in any engineered or biological system. Second, no proposal has been tabled to enable a robot in a decentralized multirobot system select its communication partners based on their location. We propose a new form of highly scalable mechanism to enable "spatially targeted communication" in such systems. Third, the question of when and how to trigger a self-assembly process has been ignored by researchers to a large extent. We propose "supervised morphogenesis" -- a control methodology that is based on spatially targeted communication and enables cooperation between aerial and ground-based self-assembling robots. We show that allocating self-assembly related decision-making to a robot with an aerial perspective of the environment can allow robots on the ground to operate in entirely unknown environments and to solve tasks that arise during mission time. For each of the three propositions put forward in this thesis, we present results of extensive experiments carried out on real robotic hardware. Our results confirm that we were able to substantially advance the state of the art in self-assembling robots by unleashing their potential for morphological adaptation through enhanced sensorimotor coordination and by improving their overall autonomy through cooperation with aerial robots.Doctorat en Sciences de l'ingénieur et technologie
info:eu-repo/semantics/nonPublished
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Hannon, Adam Floyd. "Modeling and theoretical design methods for directed self-assembly of thin film block copolymer systems." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/89842.
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Thesis: Sc. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2014.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 321-324).
Block copolymers (BCPs) have become a highly studied material for lithographic applications due to their ability to self-assemble into complex periodic patterns with feature resolutions ranging from a few to 100s nm. BCPs form a wide variety of patterns due the combination of their enthalpic interactions promoting immiscibility between the blocks and the bonding constraint through their chain topology. The morphologies formed can be tailored through a directed self-assembly (DSA) process using chemical or topographical templates to achieve a desired thin film pattern. This method combines the traditional top-down lithographic methods with the bottom-up self-assembly process to obtain greater control over long range order, the local morphology, and overall throughput of the patterns produced. This work looks at key modeling challenges in optimizing BCP DSA to achieve precision morphology control, reproducibility, and defect control. Modeling techniques based on field theoretic simulations are used to both characterize and predict the morphological behavior of a variety of BCPs under a variety of processing conditions including solvent annealing and DSA under topographical boundary conditions. These methods aid experimental studies by saving time in performing experiments over wide parameter spaces as well as elucidating information that may not be available by current experimental techniques. Both forward simulation approaches are studied where parameters are varied over a wide range with phase diagrams of potential morphologies characterized and inverse design approaches where given target patterns are taken as simulation input and required conditions to produce those patterns are outputted from the simulation for experimental testing. The studies ultimately help identify the key control parameters in BCP DSA and enable a vast array of possible utility in the field.
by Adam Floyd Hannon.
Sc. D.
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Ma, Shucong. "Subcomponent self-assembly of metal-organic supramolecular systems utilising synthesised organic ligands and metal templates." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608203.
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Khan, Siddique J. "Brownian dynamics study of the self-assembly of ligated gold nanoparticles and other colloidal systems." Diss., Kansas State University, 2012. http://hdl.handle.net/2097/13508.
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Doctor of PhilosophyDepartment of Physics
Amit Chakrabarti
We carry out Brownian Dynamics Simulations to study the self-assembly of ligated gold nanoparticles for various ligand chain lengths. First, we develop a phenomenological model for an effective nanoparticle-nanoparticle pair potential by treating the ligands as flexible polymer chains. Besides van der Waals interactions, we incorporate both the free energy of mixing and elastic contributions from compression of the ligands in our effective pair potentials. The separation of the nanoparticles at the potential minimum compares well with experimental results of gold nanoparticle superlattice constants for various ligand lengths. Next, we use the calculated pair potentials as input to Brownian dynamics simulations for studying the formation of nanoparticle assembly in three dimensions. For dodecanethiol ligated nanoparticles in toluene, our model gives a relatively shallower well depth and the clusters formed after a temperature quench are compact in morphology. Simulation results for the kinetics of cluster growth in this case are compared with phase separations in binary mixtures. For decanethiol ligated nanoparticles, the model well depth is found to be deeper, and simulations show hybrid, fractal-like morphology for the clusters. Cluster morphology in this case shows a compact structure at short length scales and a fractal structure at large length scales. Growth kinetics for this deeper potential depth is compared with the diffusion-limited cluster-cluster aggregation (DLCA) model. We also did simulation studies of nanoparticle supercluster (NPSC) nucleation from a temperature quenched system. Induction periods are observed with times that yield a reasonable supercluster interfacial tension via classical nucleation theory (CNT). However, only the largest pre-nucleating clusters are dense and the cluster size can occasionally range greater than the critical size in the pre-nucleation regime until a cluster with low enough energy occurs, then nucleation ensues. Late in the nucleation process the clusters display a crystalline structure that is a random mix of fcc and hcp lattices and indistinguishable from a randomized icosahedra structure. Next, we present results from detailed three-dimensional Brownian dynamics simulations of the self-assembly process in quenched short-range attractive colloids. Clusters obtained in the simulations range from dense faceted crystals to fractal aggregates which show ramified morphology on large length scales but close-packed crystalline morphology on short length scales. For low volume fractions of the colloids, the morphology and crystal structure of a nucleating cluster are studied at various times after the quench. As the volume fraction of the colloids is increased, growth of clusters is controlled by cluster diffusion and cluster-cluster interactions. For shallower quenches and low volume fractions, clusters are compact and the growth-law exponent agrees well with Binder–Stauffer predictions and with recent experimental results. As the volume fraction is increased, clusters do not completely coalesce when they meet each other and the kinetics crosses over to diffusion-limited cluster-cluster aggregation (DLCA) limit. For deeper quenches, clusters are fractals even at low volume fractions and the growth kinetics asymptotically reaches the irreversible DLCA case.
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Wang, Han. "Developing Novel Drug Delivery Systems For Platinum-based Anticancer Drugs Using Coordination-driven Self-assembly." Kent State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=kent1595260147978142.
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Shokri, Roozbeh [Verfasser], and Günter [Akademischer Betreuer] Reiter. "Self-Assembly of supra-molecular systems on graphene or graphite = Selbstorganisation von Supramolekularen Systemen auf Graphen oder Graphit." Freiburg : Universität, 2013. http://d-nb.info/1123475415/34.
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Haedler, Andreas T. [Verfasser], and Hans-Werner [Akademischer Betreuer] Schmidt. "Synthesis, Self-Assembly and Photophysical Properties of Multichromophoric Systems / Andreas T. Haedler. Betreuer: Hans-Werner Schmidt." Bayreuth : Universität Bayreuth, 2015. http://d-nb.info/1074461843/34.
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Nicoll, Sarah Louise. "Covalently-linked self-assembling peptide-amphiphile hydrogels for cell scaffolding applications." Thesis, University of Aberdeen, 2012. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=186975.
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A variety of “clickable” self-assembling peptide-amphiphile hydrogel systems are reported. Covalently linked hydrogels were prepared using alkyne-azide “click” chemistry and thiolene photochemistry, which were used in combination with short self-assembling peptideamphiphile compounds. For alkyne-azide “click” hydrogels, samples were formed from a mixture of two peptideamphiphiles which were separately disubstituted with alkyne or azide functionalised amino acids. This allowed for production of an extensively triazole-linked hydrogel product when gelation was performed in combination with the appropriate “click” pre-catalyst and reductant. For thiol-ene photochemical hydrogels samples were formed from a mixture of two peptideamphiphiles which were separately disubstituted with cysteine or Alloc-protected lysine. UV exposure was used to catalyse the covalent linking of the asembled hydrogel. Michael addition thiol-ene reactions were also investigated as a potential covalent linking method. A number of model reactions were attempted on specially synthesised amino acids. Results were promising, but a number of difficulties were encountered which made them unsuitable for incorporation in a hydrogel system. The hydrogel samples produced were all found to be viscoelastic hydrogels through analysis by rheological methods. A variation in the stiffness of the samples was observed, with samples having Young’s modulus values in the soft to intermediate range when compared to that of various tissues. SEM analysis indicated the hydrogels exhibited a fibrous nanostructure. The biological activity of the hydrogel samples was investigated by 2D seeding of cells on hydrogel samples. A LIVE/DEAD assay was performed which indicated hydrogel samples were able to support cell attachment and growth in vitro.
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Perera, Uduwanage Gayani E. "STM Investigation of Charge-Transfer and Spintronic Molecular Systems." Ohio University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1300141817.
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Pranger, Lawrence A. "Reactive molding and self-assembly techniques for controlling the interface and dispersion of the particulate phase in nanocomposites." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26551.
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Thesis (Ph.D)--Materials Science and Engineering, Georgia Institute of Technology, 2009.Committee Chair: Tannenbaum, Rina; Committee Member: Garmestani, Hamid; Committee Member: Jacob, Karl; Committee Member: Patterson, Tim; Committee Member: Singh, Preet. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Tison, Christopher Kirby. "Programmable, isothermal disassembly of DNA-linked colloidal particles." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28189.
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Thesis (M. S.)--Materials Science and Engineering, Georgia Institute of Technology, 2009.Committee Chair: Milam, Valeria; Committee Member: Boyan, Barbara; Committee Member: Li, Mo; Committee Member: McDevitt, Todd; Committee Member: Sandhage, Ken.
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Nguyen, Duong Thuy. "Self-assembly Polymeric Nanoparticles Composed of Polymers Crosslinked with Transition Metals for Use in Drug Delivery." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc822738/.
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A major drawback of chemotherapy is the lack of selectively leading to damage in healthy tissue, which results in severe acute side effects to cancer patients. The use of nanoparticles as a drug delivery system has emerged as novel strategy to overcome the barriers of immunogenic response, controlled release of therapeutic, and targeting the toxicity only to cancerous cells. In this study, polymeric nanoparticles composed of transition metals and particles derived from natural biopolymers have been generated via self-assembly. For example, nanoparticles composed of cobalt crosslinked with albumin (Co-alb NPs) via Co-amine coordination chemistry of lysine residue were syntheisized in various sizes. The method to generate Co-alb NPs involves no thermal heat, organic solvent or any surfactants, which is ideal for the production of large amounts in a timely manner. The Co-alb NPs displayed exceptional stability under physiological conditions (pH 7.4) for several days with minor changes in size; however degradation could be triggered by reductant (reduced glutathione (GSH), 10 mM) with complete disappearance of particles in less than 2 hour. Numerous therapeutics that are highly effective toward cancer cells have been developed; however, many cannot be administered to patients due to poor solubility in water and pH dependent properties. We have successfully encapsulated 7-ethyl-10-hydroxycampothecin (SN-38) into Co-alb NPs with encapsulation efficiency as high as 94% and loading capacities greater than 30%. We employed an emulsion-solvent evaporation method to incorporate SN-38 into Co-alb (SN38 Co-Alb NPs). Release of the drug from SN38 Co-Alb NPs was determined for particles incubated in PBS or PBS-GSH. SN38 Co-Alb NPs were exceptionally stable under physiological condition (PBS pH 7.4), but exhibited sustained release of SN-38 over time in the presence of GSH. Uptake and toxicity of the particles were also investigated in a gastric carcinoma cell line (SNU-5) where high degrees of macropinocytic uptake were observed. The particles displayed significant toxicity making them a prime candidate for further testing in animal models.
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Hurley, Margaret M. "Analysis of the dipolar lattice gas as a model for self-assembly in 1 and 2-dimensional systems /." The Ohio State University, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487780393265179.
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Sommer, Samantha. "Hybrid Metal-Ligand Hydrogen-Bonded (MLHB) Architectures Based on the Quinolone Subunit: Understanding and Expanding the Accessible Space of Supramolecular Systems." Thesis, University of Oregon, 2015. http://hdl.handle.net/1794/19298.
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Despite the prevalence of supramolecular architectures derived from metal-ligand or hydrogen-bonding interactions, few studies have focused on the simultaneous use of these two strategies to form discrete metal-ligand hydrogen-bonded (MLHB) assemblies.
The design, synthesis, and characterization of 2-quinolone based hybrid subunits, 7-DPQ and 5-PYQ, that contain phosphine and pyridyl metal binding sites, respectively, is reported. Both subunits give two-fold symmetric hydrogen-bonded tectons that assemble with metal precursors to give hybrid MLHB structures. Treatment of [Cp*RhCl2]2 with the 7-DPQ subunit yields hybrid MLHB assemblies with closed topology. 1H diffusion ordered spectroscopy experiments established the stability of the structures in solution, and the measured hydrodynamic radii match those determined crystallographically, suggesting that the closed topology is maintained in solution and the solid state.
In order to further explore possible MLHB architectures and test the selectivity boundaries of our quinolone-based subunits we report the selective assembly of 5-PYQ with mono- and bis-platinated anthracene precursors. Addition of 5-PYQ to [1-trans-Pt(PEt3)2NO3]-8-chloroanthracene yielded a hybrid MLHB structure with preorganization for a hybrid MLHB polymer. Despite the systems preorganization for the hybrid polymeric structure the assembly of 5-PYQ with 1,8-bis(trans-Pt(PEt3)2NO3)anthracene selects only for one discrete closed self-assembled macrocycle. The strong π-π stacking interactions of the 5-PYQ subunits erode the hydrogen-bonding fidelity to favor ambidentate coordination modes of 5-PYQ and give the non-hybrid macrocycle.
In the course of investigating the intricacies of hybrid MLHB supramolecular structures we observed that, in addition to metal-ligand and hydrogen-bond interactions, the π-π stacking interactions of the 7-DPQ and 5-PYQ subunits played a critical role in determining the final assemblies. In fact, the prominent π-π interactions were typically found to be more favorable than the quinolone interligand hydrogen-bonding interactions.
These results contribute to the overall knowledge of the design principles, synthesis, characterization, and fundamental assembly trends when exploiting both hydrogen-bonding and metal-ligand interactions to form stable supramolecular architectures. These studies have provided the foundation for expanding the accessible space of supramolecular chemistry to include rationally designed hybrid MLHB systems to give structures that more closely mimic the complex supramolecular systems observed in Nature.
This dissertation includes both previously published/unpublished and co-authored material.10000-01-01