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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Using Network Models to Predict Steelhead Abundance, Middle Fork John Day, OR

Blanchard, Monica R. 01 May 2015 (has links)
In the management of threatened and endangered species, informed population estimates are essential to gage whether or not recovery goals are being met. In the case of Pacific salmonids, this evaluation often involves sampling a small subset of the population and scaling up to estimate larger distinct populations segments. This is made complicated by the fact that fish populations are not evenly distributed along riverscapes but respond to physical and biological stream properties at varying spatial extents. We used rapid assessment survey methods and the River Styles classification to explore fish-habitat relationships at a continuous network scale. Semi-continuous surveys were conducted across nine streams in the upper Middle Fork John Day River watershed and increased the number of sites surveyed eight-fold over other monitoring methods within the watershed. Using this increased sample size and continuous habitat metrics we improved watershed-wide steelhead (Oncorhynchus mykiss) abundance models. We first validated the distinctions among River Styles through a classification analysis using physical metrics measured at the rapid assessment sites. Overall classification accuracy, using a combination of reach and landscape scale metrics, was 88.3% and suggested that River Style classification was identifying variations in physical morphology within the watershed that was quantifiable at the reach scale. Leveraging the continuous River Styles classification of physical habitat and a continuous model of primary production improved the prediction of steelhead abundance across the network. Using random forest regressions, a model that included only habitat metrics resulted in R2 = 0.34, while using the continuous variables improved the model accuracy greatly to R2 = 0.65. Random forest allowed for further investigation into the predictor variables through the analysis of the partial dependence plots and identified a gross primary production threshold, below which production might be limiting steelhead populations. This method also identified the rarest River Style surveyed within the watershed, Confined-Valley Step Cascade, as the morphology that had the largest marginal effect on steelhead. The inherent physical properties and boundary conditions unique to each River Style has the potential to inform fish-habitat relationships across riverscapes and improve abundance estimates on a continuous spatial scale.
72

Managing the procurement process during scale-up: A case study of a European Battery Manufacturer / Hantering av inköpsprocessen under expansion: En fallstudie av en europeisk batteritillverkare

Bergqvist, Lisa, Holm Öste, Sofia January 2023 (has links)
The European battery market is in rapid growth and the industry actors are ramping up production as well as exploring international expansion opportunities. However, due to the relative novelty of the industry in Europe, there is a lack of benchmark companies and established frameworks for successful expansion. Existing studies in this field primarily focus on strategic solutions such as sourcing strategies and supplier relationship management, neglecting the utilization of supporting operative functions. Although some studies acknowledge the significance of these supporting functions, there is a lack of research providing models for their utilization. This research gap motivates the aim of this study to address this issue and contribute to the existing literature. The purpose of this study is to develop a comprehensive and adaptable expansion strategy that European battery manufacturers can employ when expanding their production facilities, while ensuring a high-quality procurement function. This was met by collecting qualitative data through interviews. The interviews were primarily with respondents from the case company, supplemented by inputs from relevant external participants. By conducting a case study focusedon the procurement department, valuable insights were gained, and the identified expansion strategy can serve as a valuable resource for industry practitioners. The main finding of this research is the battery manufacturers need for a structured expansion step model that outlines both the execution steps and their sequential order. The steps of the framework are: (1) Assure Management Support, (2) Create a Dedicated Expansion Team, (3) Adjust & Consolidate Systems, (4) Define Roles & Responsibilities, (5) Train & Incentives Employees, (6) Control Access Management, (7) Create & Maintain Master Data, and lastly, (8) Initial Supplier Contact. / Batterimarknaden i Europa växer snabbt. Företagen ökar sin produktion samtidigt som de undersöker möjligheter till att expandera internationellt. Vidare är marknaden i Europa relativt ny. Det innebär att det saknas större etablerade företag, riktlinjer och system att jämföra sig med om hur man expanderar på bästa sätt. Tidigare studier inom området har främst fokuserat på strategiska lösningar, såsom inköpsstrategier och hantering av leverantörer, men har förbisett utforskandet av hur man ska använda stödjande operativa funktioner. Även om vissa studier betonar vikten av dessa stödfunktioner är forskning som tillhandahåller modeller för användning av stödfunktioner bristfällig. Detta forskningsgap motiverar syftet med studien, vilken är att fokusera på modeller och bidra till den befintliga litteraturen. Målet med denna studie är att utveckla en omfattande och anpassningsbar expansionsstrategi som europeiska batteritillverkare kan använda vid expansion av sina produktionsanläggningar samtidigt som de säkerställer en högkvalitativ inköpsfunktion. För att uppnå detta har kvalitativa data samlats in genom intervjuer. Intervjuerna har främst genomförts med respondenter från det studerade företaget och har kompletterats med bidrag från relevanta externa deltagare. Genom att genomföra en fallstudie inom inköpsområdet har många värdefulla insikter erhållits, framför allt den identifierade expansionsstrategin som kan ses som en värdefull resurs för batteritillverkare. Det huvudsakliga resultatet av denna forskning är att batteritillverkarna har behov av en strukturerad stegmodell för expansion som tydligt anger både utförandestegen och deras sekventiella ordning. Stegen i ramverket är: (1) Säkra ledningens stöd, (2) Skapa en dedikerad expansionsgrupp, (3) Anpassa & konsolidera system, (4) Definiera roller & ansvar, (5) Utbilda & ge incitament till anställda, (6) Kontrollera åtkomst (7) Skapa & underhålla master data, och slutligen, (8) Initiera leverantörskontakt.
73

MOBILE PHONE TEXT MESSAGING FOR ADHERENCE TO ANTIRETROVIRAL THERAPY: APPROACHES TO EVIDENCE GENERATION AND SCALE UP

Mbuagbaw, Lawrence January 2014 (has links)
Background and Objectives: HIV in a major public health problem in many countries of the world. Recent advances in care for people living with HIV such as the use of antiretroviral medication have reduced the mortality and morbidity associated with HIV infection. However, many people receiving antiretroviral therapy do not take it as prescribed and still experience sub-optimal health outcomes. Mobile phone text messaging is emerging as an important tool in health care, and HIV in particular. Our objectives were to explore the determining factors for adherence to antiretroviral therapy, test text messaging as an adherence enhancement tool, develop a framework for community ownership of a text messaging program and describe strategies for transfer of evidence in HIV to other conditions. Methods: This research is primarily based in Yaoundé, Cameroon, and employs a variety of methodologies, including a systematic review, two cross- sectional surveys, a randomized controlled trial, an individual patient data meta-analysis, a mixed methods study and a systematic review of systematic reviews. Results and Conclusions: Two-way weekly text messaging is an effective strategy in improving adherence to antiretroviral therapy and enhancing provider-client communication. People living with HIV in Yaoundé, Cameroon like receiving text messages, and are willing to own and run a text messaging program. Text messaging interventions may be transferred to other conditions by integrating services or by copying what works in HIV. Further research on potential harms, cost effectiveness and text messaging for other chronic conditions is warranted. / Thesis / Doctor of Philosophy (PhD)
74

Scaling up early childhood development programs in low- and middle-income countries: understanding the determinants of scaling up early childhood development in Zambia

Alade, Mayowa Oluwatosin 04 August 2023 (has links)
BACKGROUND: Evidence supports the importance of Early Childhood Development (ECD) interventions to improve children's health, lifelong productivity, and human capital. However, ECD programs are not scaled sufficiently to reach many of the 250 million young children globally who are not meeting their developmental potential. Practical guidance is limited on how to scale ECD programs effectively. This mixed-method study explored the contextual and implementation determinants of scaling up ECD programs in Zambia, using one large-scale, community-based parenting group program (Scaling Up Early Childhood Development in Zambia (SUpErCDZ) program) as a case study. The goal was to generate recommendations for policymakers and implementers in Zambia and other LMICs. METHODS: This study was guided by the WHO/ExpandNet scale-up framework and the Intervention Scalability Assessment Tool (ISAT). A total of 30 key informant interviews were conducted with program staff, government officials, academic partners, implementing partners of other ECD programs, and donors. Qualitative transcripts were analyzed using thematic analysis according to the framework method. A budget impact analysis (BIA) was conducted using prospectively collected program cost and implementation data supplemented by online sources and interviews with program staff. The total cost of scale-up over five years using three scenarios (low, medium, and high intensity) was modeled. RESULTS: According to government officials, donors, and partners, the most common contextual factors influencing scale-up ECD programs are political commitment, availability of an overarching or multisectoral ECD policy, availability of resources, and integration of ECD programs into existing government structures. In addition, multisectoral collaboration, stakeholders’ engagement, and sociocultural factors emerged as themes essential to scale-up. From the perspective of the program staff, the key facilitators of ECD implementation were stakeholders’ engagement, sociocultural factors (cultural norms and beliefs), adaptation of the intervention to the context, integration into existing government structures, and intervention characteristics. In addition, providing incentives to Community-Based Volunteers (CBVs) emerged as critical to sustainability. The main barriers to implementation identified by the program staff were the use of culturally inappropriate activities within the ECD curriculum, lack of incentives (financial or in-kind) to caregivers and CBVs, and unforeseen contextual circumstances (COVID-19 pandemic and insecurity). The budget impact analysis showed that the total cost and budget for scaling up SUpErCDZ or a similar ECD program depends on the magnitude of the scale-up in terms of geographic breadth and depth (coverage within specific geographic areas). Based on our scale-up scenarios, the estimated cost of scaling up this program over five years ranged between US$1.74M to US$4.3M depending on the breadth (how many provinces) and depth (how many health facilities, CBVs, and caregivers) of implementation. CONCLUSION: Multiple complex and interrelated contextual and implementation factors influence the scaling up of ECD programs in Zambia. To ensure equitable access to ECD programs for children under five in Zambia, policymakers and implementers will need to consider these when planning to scale up ECD interventions in Zambia. / 2025-08-04T00:00:00Z
75

Procédés de mise à l’échelle pour la fabrication et la caractérisation de biocapteurs de graphène à effet de champ

Bencherif, Amira 08 1900 (has links)
Alors que la découverte de matériaux conducteurs de faible dimension fait progresser la mi- niaturisation des composants électroniques, les transistors à effet de champ (FET) peuvent désormais incorporer des éléments à molécule unique comme canal ou grille. Ces petites architectures permettent, entre autres, l’étude de molécules uniques, notamment par l’ob- servation de leur dynamique de repliement-dépliement ou de liaison. Ces études ont été principalement réalisées avec des transistors à effet de champ à base de matériaux unidimen- sionnels (1D) tels que les nanotubes de carbone (CNT) ou les nanofils de silicium. Du fait de leur dimensionnalité réduite, ces matériaux offrent un bon contrôle de leur interaction avec les molécules 0D, et donc de leur intégration au circuit. Cependant, ces matériaux 1D présentent des problèmes de reproductibilité et de mise à l’échelle, du fait qu’ils sont difficiles à croître et/ou à assembler dans les dispositifs FET. Cette thèse s’intéresse à l’utilisation d’un matériau carboné à deux dimensions, le gra- phène, comme alternative pour la fabrication de dispositifs pour l’étude de dynamiques de molécules uniques. En effet, le graphène est un matériau à deux dimensions composé d’un ré- seau hexagonal d’atomes de carbone, avec une excellente conductivité électrique ainsi qu’une chimie à base de carbone permettant l’ancrage de molécules biologiques à sa surface, ce qui en fait un candidat de choix pour la détection électrique de molécules individuelles. Sa di- mensionnalité est aussi compatible avec des procédés de microfabrication à grande échelle, ce qui offre la possibilité d’études statistiques sur de grands nombres de dispositifs. Ainsi, la détection de molécules biologiques utilisant des transistors à effet de champs à base de graphène (GFET) a connu un développement et un engouement important au cours de la dernière décennie, mais plusieurs aspects restent à résoudre, notamment la mise à l’échelle de la fabrication, le contrôle de la chimie de fonctionnalisation, et la miniaturisation du canal à l’échelle de la molécule unique. Dans cette thèse, des contributions sur ces trois aspects sont présentées. Premièrement, je décris une méthode de mise à l’échelle du transfert de graphène dans une optique d’indus- trialisation, par la conception et l’implémentation d’un montage de transfert de graphène permettant l’automatisation et l’augmentation du rendement de la fabrication de GFET. Je m’intéresse ensuite à la fonctionnalisation des dispositifs de graphène avec une molécule d’ancrage communément utilisée dans le cas des biodétecteurs basés sur des GFET, afin de révéler les cinétiques associées à l’adsorption et à l’accumulation de la molécule à la surface du graphène. Enfin le dernier chapitre décrit la conception d’une architecture de GFET pour l’accueil d’une molécule unique d’ADN, basée sur des nanoconstrictions mises en place dans le canal de graphène. Ces constrictions ont été obtenues à l’aide de la lithographie par faisceau d’électrons (EBL) et gravure ionique réactive profonde (DRIE), qui nous permet de modeler des structures à haute résolution de quelques dizaines de nanomètres dans le canal de graphène. Des nanopuits perpendiculaires à la constriction sont par la suite ouverts dans de la résine, favorisant le confinement de la chimie d’immobilisation de la molécule unique en un seul point. J’explore ensuite la liaison d’un brin unique d’ADN sur la nanoconstriction, et l’étude dynamique de son repliement. Cette thèse présente donc des résultats innovants en termes d’architectures et de procédés de mise à l’échelle de GFET à des fins de biodétection. / With the discovery of low-dimensional conductive materials advancing the miniaturization of electronic components, field-effect transistors (FET) can now incorporate single-molecule elements as a channel or gate. Among their applications, these small architectures allow single-molecule studies, for instance by observing their folding-unfolding or binding dy- namics. These studies were mainly carried out with field-effect transistors based on one- dimensional (1D) materials such as carbon nanotubes (CNT) or silicon nanowires (SiNW). Due to their reduced dimensionality, these materials offer good control on their interaction with 0D molecules, and therefore of their integration into the circuit. However, these 1D materials present reproducibility and scaling issues, due to the fact that they are difficult to grow and/or assemble in FET devices. This thesis focuses on the use of a two-dimensional carbon-based material, graphene, as an alternative for the fabrication of devices for studying the dynamics of single molecules. Graphene is a hexagonal network of carbon atoms that offers an excellent electrical conduc- tivity as well as a carbon-based chemistry for anchoring biological molecules on its surface, this makes it a prime candidate for the electrical detection of individual molecules. Above all, its dimensionality is compatible with large-scale microfabrication processes, which offer the possibility of statistical studies on a large number of devices. Thus, the detection of biological molecules using graphene-based field-effect transistors (GFET) has experienced significant development over the past decade, but several aspects remain to be resolved, including scale- up of the manufacturing, control of the functionalization chemistry, and miniaturization of the channel at the single molecule scale. In this thesis, I present contributions on these three aspects. First, I describe a method for scaling up graphene transfer in an industrialization perspective, by designing and implementing a graphene transfer setup allowing automation for increasing the yield of GFET fabrication. I then focus on the functionalization dynamics of graphene devices with an anchor molecule named PBASE (1-Pyrenebutyric acid N-hydroxysuccinimide ester) commonly used in the case of GFET-based biosensors, which reveals the adsorption and accumulation kinetics of the molecule on the graphene surface. Finally, I describe the design of a GFET architecture based on nanoconstrictions implemented in the graphene channel, designed to host a single molecule. These constrictions were obtained using electron beam lithography (EBL) and deep reactive ion etching (DRIE), which allows the modeling of high-resolution features of a few nanometers in the graphene channel. Nanowells were opened in the resin perpendicular to the constriction, promoting single-point, single-molecule chemistry. I then explore the immobilization of a single strand of DNA on nanoconstriction, and the dynamic study of its folding. This thesis therefore presents innovative results in terms of architectures and scaled implementation processes of GFET for biodetection purposes.
76

Process Study, Simulation, and Optimization of the Direct Conversion of Biomass to Ethyl Levulinate

Woloszyn, Joanne 31 August 2023 (has links)
Lignocellulosic biomass is a promising alternative to non-renewable fossil fuel resources for the sustainable production of fuels and chemicals. Levulinic acid (LA) is considered to be a versatile platform chemical which can be derived from biomass and further upgraded to high-value products like levulinate esters. In this work, the direct chemical conversion of lignocellulosic biomass to ethyl levulinate (EL) through LA was studied in collaboration with Gascon Biomass Research Inc. in an effort to valorize their surplus of lignocellulosic feedstock obtained from biomass recycling activities. A novel one-pot, biphasic, acid-catalyzed hydrolysis-esterification process developed by Prof. Tom Baker's lab (uOttawa Chemistry) was used. Kinetic analyses of the overall reaction pathway and major reaction steps were performed to investigate the effect of reaction conditions such as time, temperature, alcohol concentration, and catalyst concentration and evaluate the kinetic and thermodynamic parameters. Reactions were well modeled by power law rate equations with applicability of the Arrhenius expression and exhibited nearly first-order dependence with respect to each of the corresponding reactants and catalyst, as expected. Kinetic studies of LA esterification to various levulinate esters showed that the reaction is endothermic, endergonic, non-spontaneous, and non-rate-limiting. Increased alcohol alkyl chain length and branching reduced the thermodynamic favourability of LA esterification, likely due to steric effects. Process considerations such as reactor pressure, LA and EL partitioning, solvent:feedstock ratio, solvent recycling, and alternative feedstocks were investigated through various lab-scale studies and simulation case studies with UniSim® Design. The results of experimental studies informed the development of a preliminary potential process flow diagram consisting of eleven batch slurry reactors under agitation in parallel. The product streams feed into a continuous separation process composed of flash vessels and distillation columns to separate and purify the various products, intermediates, unconsumed reactants, and recoverable catalyst and solvent. This work ultimately informs decisions regarding future pilot-scale experiments, process design, and optimization for the envisioned large-scale biorefinery to produce EL.
77

An investigation on process of seeded granulation in a continuous drum granulator using DEM

Behjani, M.A., Rahmanian, Nejat, Ghani N.F.b.A., Hassanpour, A. 22 February 2017 (has links)
Yes / Numerical simulation of wet granulation in a continuous granulator is carried out using Discrete Element Method (DEM) to discover the possibility of formation of seeded granules in a continuous process with the aim of reducing number of experimental trials and means of process control. Simple and scooped drum granulators are utilized to attain homogenous seeded granules in which the effects of drum rotational speed, particles surface energy, and particles size ratio are investigated. To reduce the simulation time a scale-up scheme is designed in which a dimensionless number (Cohesion number) is defined based on the work of cohesion and gravitational potential energy of the particles. Also a mathematical/numerical method along with a MATLAB code is developed by which the percentage of surface coverage of each granule is predicted precisely. The results show that use of continuous granulator is promising provided that a high level of shear is considered in the granulator design, e.g. it is observed that using baffles inside the drum granulators is essential for producing seeded granules. It is observed, moreover, that the optimum surface energy for scooped granulator with rotational speed of 50 rpm is 3 J/m2 which is close to the number predicted by Cohesion number. It is also shown that increasing the seed/fine size ratio enhances the seeded granulation both quantitatively (60% increase in seeds surface coverage) and qualitatively (more homogeneous granules).
78

Lab experiments using different flotation cell geometries

de Souza, Carolina Vivian January 2020 (has links)
Due to the increasing demand for processing low-grade ores, larger volumes of material are being processed. Therefore, the size of flotation equipment has significantly increased for the past decades. The studies related to scale-up are and will remain to be crucial in terms of designing larger flotation equipment. One of the most important factors for flotation scaling-up is the “flotation rate constant”. Hence, the main aim of this investigation was to understand the scale-up criteria when the size of different laboratory-scale cells increases, using the Outotec GTK LabCell®. This was done by assessing the influence of impeller speed, as a hydrodynamic variable, on the flotation performance. Recovery was found to increase with an increase in the cell area to rotor diameter ratio. Flotation rate and recovery increased with an increase in the impeller speed until a certain point that it eventually decreased for the 2 l and 7.5 l cells. For the 4 l cell, the flotation rate and recovery decreased with increasing the impeller speed. The impeller speed of 1200 rpm allowed a successful scale-up based on the flotation rate constants and recovery when increasing the size of the cells. Maintaining the impeller speeds constant at 1300 rpm increased the flotation rate constants and recovery when increasing the cell size from both the 2 and 4 l cells to the 7.5 l cell. A further increase in the impeller speed to 1400 rpm also produced the flotation rate constants and recovery to increase as the cell size increased from both the 2 and 4 l cells to the 7.5 l cell. However, when increasing the cell size from 2 l to 4 l, good results were also observed for all impeller speeds. The products concentrate seem to become finer when decreasing the cell size, with only a few exceptions. The recovery of particles larger than 38 μm was found to differ considerably less among the different scales.
79

Fundamental Investigations of Supercritical Fluid Chromatography

Enmark, Martin January 2015 (has links)
This thesis aims at a deeper understanding of Supercritical Fluid Chromatography (SFC). Although preparative SFC has started to replace Liquid Chromatography (LC) in the pharmaceutical industry - because of its advantages in speed and its less environmental impact - fundamental understanding is still lacking. Therefore there is no rigid framework to characterize adsorption or to understand the impact of changes in operational conditions.   In Paper I we demonstrated, after careful system verification, that most methods applied to determine adsorption isotherms in LC could not be applied directly in SFC. This was mainly due to operational differences and to the fact that the fluid is compressible which means that everything considered constant in LC varies in SFC.   In Paper II we showed that the most accurate methods for adsorption isotherm determination in LC, the so called plateau methods, do not work properly for SFC. Instead, methods based on overloaded profiles should be preferred.   In Paper III a Design of Experiments approach was successfully used to quantitatively describe the retention behavior of several solutes and the productivity of a two component separation system. This approach can be used to optimize SFC separations or to provide information about the separation system.   In Paper IV severe peak distortion effects, suspected to arise from injection solvent and mobile phase fluid mismatches, were carefully investigated using experiments and simulations. By this approach it was possible to examine the underlying reasons for the distortions, which is vital for method development.   Finally, in Paper V, the acquired knowledge from Paper I-IV was used to perform reliable scale-up in an industrial setting for the first time. This was done by carefully matching the conditions inside the analytical and preparative column with each other. The results could therefore provide the industry with key knowledge for further implementation of SFC. / This thesis aims at a deeper understanding of Supercritical Fluid Chromatography (SFC). Although preparative SFC has started to replace Liquid Chromatography (LC) in the pharmaceutical industry - because of its advantages in speed and its less environmental impact - fundamental understanding is still lacking. Therefore there is no rigid framework to characterize adsorption or to understand the impact of changes in operational conditions.   In Paper I-II it was demonstrated why most methods applied to determine adsorption isotherms in LC could not be applied directly for SFC. Methods based on extracting data from overloaded profiles should be preferred.   In Paper III a Design of Experiments approach was successfully used to quantitatively describe the behavior of several solutes in a separation system. This approach can be used to optimize SFC separations or to provide information about the separation system.   In Paper IV severe peak distortion effects often observed in SFC were carefully investigated and explained using experiments and simulations.   Finally, in Paper V, the prerequisites for performing reliable and predictable scale-up of SFC were investigated by small and large scale experiments. / <p>Paper 4 ("Evaluation of scale-up from analytical to preparative...") ingick som manuskript med samma titel i avhandlingen. Nu publicerad. </p>
80

Development of a PP-MOCVD System and its Design and Operational Parameters for Uniform Industrial Coatings on 3D Objects

Lee, Darryl Liang Wee January 2014 (has links)
Increase in demand for uniform ceramic coatings on larger industrial components have led to a need for a PP-MOCVD coating system scale up. The objective of this thesis is to develop a fully functional coating system operating in the PP-MOCVD regime that is able to deposit thin film ceramic coatings on commercial or industrial components with complex 3D geometries. This can be achieved by applying engineering and vacuum science theories, coupled with the established fundamentals of PP-MOCVD. A larger system was designed and assembled around the boundaries set by the dimensions and geometry of a stainless steel water pump impellor acting as the base substrate. Most of the components were sourced off the shelf from vacuum and fluid specialists. Components which were unavailable for various reasons were designed, and machined in-house by the departmental workshop. Initial test depositions were conducted using small stainless steel disk substrates, heated using a resistive heater similar to the one utilised on the research scale system. The test depositions were performed with the heater and substrate combination placed in strategic locations. This is to test the overall uniformity of precursor flux in the chamber volume. The resulting coating uniformity on the disk surfaces were fair but problems such as the large collection of unreacted precursor on the chamber viewport and valve timing issues had to be addressed. Before making any improvements to the system, each of the process areas leading to a successful deposition needed to be understood. Five process areas were developed: ‘Liquid Delivery’, ‘Atomization’, ‘Evaporation’, ‘Transport and Reactor Geometry’, and ‘Droplet Management’. Each of the process areas were analysed individually and changes were made to push for a maximum evaporation efficiency. xviii The improved system provided opportunities to perform depositions that were once not possible for PP-MOCVD. Two sets of deposition tests were designed and conducted. Firstly, the improvements were justified with a series of depositions using flat stainless steel plates with dimensions 65x65x5mm. The other set of 3D case study depositions involve observing the effects of the operational parameters of PP-MOCVD on the uniformity and penetration depths of the coatings into different sized macro blind trenches. Five geometric setup conditions were used to justify the improvements made to the system. These are: ‘Substrate positioned in the direct line of spray’, ‘Use of an unheated receptor’, ‘Use of a heated receptor’, ‘Use of an unheated receptor with a non-axial substrate setup’, and “Choked Flow’. As expected, the uniformity of the coatings on both sides of the plate varied significantly when the substrate is placed over the line of sight of the precursor spray. Similarly, the coating produced under the induced choked flow condition resulted in low conformality. The introduction of an unheated receptor plate resulted in an increase in uniformity on both sides of the plate. Further prove that PP-MOCVD is geometry independent is provided by the deposition made with the non-axial substrate placement resulting in a coating of similar result to the unheated receptor. The use of a heated receptor provided a source for a secondary evaporation of the larger precursor droplets collected resulting in an increase in coating thickness while maintaining good conformality. The effects of temperature, pressure, injection volume, and concentration were explored in the final case study. With maximum depths of 50mm, the macro blind trenches has an aspect ratio of 1:1 and cross-sectional areas of 3x3mm, 9x9mm, and 15x15mm. The final results show that as the temperature rises, the depth penetrated into the trench decreases. This could be due to the change in rate limiting steps as homogeneous reactions begin to increase at higher temperatures. Similar trends were observed with increasing pressure. As the pressure difference between the volume of the trenches and the rest of the chamber decreases, the push needed to xix force the precursor down the trench also decreases, resulting in less depth penetration. The effects of injection volume and concentration observed, can be explained by how much precursor molecules are present during one pulse cycle. The more that is available at any given time, the more likely a reaction will occur and deeper the penetration will get. Of course a ceiling or a limit exists where the molecules in the chamber will get evacuated without being reacted. The future work made possible as a result of the scaled up system are proposed. These include a scale up of the operational parameters to suit any given substrate geometry, improvements to the heating source to achieve greater thermal uniformity, further improvements to the overall system accessibility, and performing other depositions using different substrate materials and precursor types.

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