Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 34 for “"nucleation kinetics"”.
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Nucleation kinetics in alkali amalgam vapors.
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 1973
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Studies of Thin Film Nucleation Kinetics (Island Growth)
Thin film nucleation theory for the island growth model has long been a subject of intensive study because understanding of the nucleation mechanisms should improve the attainable film morphologies. In spite of the long history of nucleation theory, the current status of the theory is not able to …
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Crystal growth and nucleation kinetics of diethylenetriammonium hexachlororhodate (III) salt
… The objective of this work is to determine nucleation and growth kinetics of diethylenetriammonium hexachlororhodate (III) salt. Two reactor configurations, namely a transient continuous stirred tank reactor (CSTR) and a t-mixer plug flow reactor (PFR), were used to determine nucleation and …
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Analysis of nucleation kinetics in pH-shift crystallization using agitated and microfluidic systems
Crystal nucleation is a key event in the process of crystallization and is important in a number of processes in the pharmaceutical industry. Nucleation kinetics impact the crystal quality attributes of the product of a crystallization process. For example, increased crystal nucleationrate can lead …
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Initial surface reactions and nucleation kinetics of boron on atomically clean molybdenum substrates
… <p>The time-dependent adsorption, leading to nucleation of boron on molybdenum field emitter surfaces has been observed to occur at about 0.5 monolayer coverages of boron.</p> <p>LEED studies of a Mo(100) single crystal at substrate temperatures of 700°C to 900°C in BI<sub>3</sub> partial …
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Nucleation Kinetics During Homoepitaxial Growth of Titanium Nitride(001) by Reactive Magnetron Sputtering
I use scanning tunneling microscopy to study the nucleation of homoepitaxial stoichiometric TiN layers grown on TiN(001) by ultrahigh vacuum reactive magnetron sputtering in pure N2. Nucleation lengths are measured using in-situ scanning tunneling microscopy as a function of temperature and …
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An Investigation of Phase Behavior and Crystal Nucleation Kinetics in Solutions of Globular Proteins
Nucleation and growth of low defect density structures remains a significant technological challenge. Indeed, when dealing with nanoparticles with chemically heterogeneous surfaces, locating crystallizing conditions remains an art rather than a science. Particular examples of these problems can be …
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Insight into Nucleation Kinetics of Flufenamic Acid Cocrystal Formulation in Solution: Investigating the Role of Polymeric Excipients through Combined Experimental and Computational Approaches
This thesis investigates the nucleation kinetics and molecular interactions in flufenamic acid (FFA) cocrystal systems, with a particular focus on the role of polymeric excipients. The impact of selected polymers, polyvinyl pyrrolidone (PVP), polyvinylpyrrolidone-vinyl acetate copolymer (PVP-VA), …
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Molecular dynamics modeling of orientation-induced nucleation in short alkanes : toward molecular modeling of flow-induced crystallization in polymers
The enhancement of the primary flow-induced nucleation rate in short chain alkanes (C20 and C150) has been examined for different levels of orientation by atomistic molecular dynamics simulations. The nucleation rate has been found to change drastically by varying average molecular orientation and …
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Phase behaviour and crystal nucleation in complex multicomponent system
… for high control of product quality attributes. Nucleation is a key phenomenon in crystallisation that can control product purity, morphology and crystal size distribution. Despite the use of co-crystallisation in manner mentioned above, not a lot is known about nucleation kinetics in …
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Morphological Evolution During Molecular Beam Epitaxy of Germanium/germanium(001) and Silicon/germanium(111)
… a systematic investigation of the island nucleation kinetics, morphology and microstructure for various thicknesses and deposition temperatures. The islands formed are predominantly three-dimensional. A large density of islands (>1011 cm-2) is observed during growth at low temperatures …
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Transparent-to-dark electrochromic behavior in naphthalene-diimide-based mesoporous MOF-74 analogs
… Mg²+ and Ni²+ ions is likely controlled by the nucleation kinetics of Mg₂(NDISA) and Ni₂(NDISA), respectively. Both materials exhibit well-behaved quasi-reversible redox events associated with the [NDI]/[NDI]̇'- and [NDI]̇̇-/[NDI]²- redox couples, which are also responsible for the …
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Investigation into the kinetics, mechanisms and particle characteristics of selenium precipitation from copper sulphate solution.
… high supersaturation conditions which favour nucleation over any other particle formation processes. There is currently no fundamental information on the nucleation kinetics of this important process. Furthermore, the fundamental chemistry and mechanisms involved in this process are not fully …
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Particle assisted protein crystal nucleation as a protein purification platform for pharmaceutical manufacturing
Slow protein crystal nucleation is a major barrier to using crystallization as a separation and purification strategy in protein drug manufacturing. This work investigates the use of functionalized nanoparticles in solution to act as in situ templates for initiating crystal nucleation. We used …
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Grain boundary precipitation in aluminum alloy 7075
… spacing is attributed to lower grain boundary nucleation kinetics at the intermediate annealing temperature and subsequent coarsening of grain boundary precipitates at the high aging temperature.
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Influence of impurities on the crystallisation of pharmaceutical materials
… samples and their effect on induction time and nucleation kinetics. Crystallisation from solution plays a significant role in the pharmaceutical, chemical and food industry, because it is widely used as a separation and purification technique. Nucleation is the first step of crystallisation, …
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Computational electronic structure studies of novel condensed matter phases
… this time into its superionic properties. The nucleation, kinetics, and correlation of lattice strain to the order-disorder superionic phase transition were explored through a combination of transmission electron microscopy and DFT. The correlation between lattice strain and superionicity is …
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Molecular simulation of nucleation from flowing polymer melts
… processing, flow drastically accelerates the kinetics of polymer crystallization, altering the morphology and properties of the resulting material The earliest stage of flow-induced crystallization, known as flow-enhanced nucleation (FEN), is challenging to study experimentally due to the …
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Crystallization process development and spherical agglomerates for pharmaceutical processing applications
… obtain kinetic parameters for crystal growth and nucleation for both systems. The models were used to optimize crystal purity and yield of the products. In addition, this thesis describes two separate projects involving spherical agglomerates. In the first study, acetaminophen was shown to …
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Design of polymeric substrates for controlled molecular crystallization
… crystallization starts with heterogeneous nucleation at a foreign surface. Despite its widespread occurrence, mechanistic understanding of the role of a surface in heterogeneous nucleation is limited, especially in a solution environment. My thesis aims at elucidating the roles of surface …
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