Дисертації з теми "029902 Complex Physical Systems"
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Fenley, Andrew Townsend. "Simple Physical Approaches to Complex Biological Systems." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/38819.
Повний текст джерелаPh. D.
Greenhough, John. "Signatures of highly-correlated processes in complex physical systems." Thesis, University of Warwick, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397525.
Повний текст джерелаRobertson, Craig Collumbine. "Building complex systems based on simple molecular architectures." Thesis, University of St Andrews, 2011. http://hdl.handle.net/10023/2573.
Повний текст джерелаDai, Mehmet Naci Carleton University Dissertation Engineering Mechanical and Aerospace. "Automating the analysis of complex physical systems - the virtual foundry." Ottawa, 1994.
Знайти повний текст джерелаWang, Ying. "Simulating complex hydro-geomorphic changes in lake-catchment systems." Thesis, University of Southampton, 2013. https://eprints.soton.ac.uk/363745/.
Повний текст джерелаFrancis, John Charles. "Qualitative system theory : a systems approach to modelling complex physical processes." Thesis, Heriot-Watt University, 1986. http://hdl.handle.net/10399/1080.
Повний текст джерелаJeziorek, Peter Nicholas 1981. "Cost estimation of functional and physical changes made to complex systems." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/30313.
Повний текст джерелаIncludes bibliographical references (p. 63).
Current cost estimation practices rely on statistically relating physical parameters of a system to historical cost data. Unfortunately, this method is unable to effectively communicate the increasing complexity of system design to cost data. Additionally, current cost estimation techniques have had a historical inability to produce credible and explainable results. It is often considered to be a "black art" with the recurring question: "Where did that number come from?" This thesis systematically links design and cost information together, and demonstrates the utility of that link by estimating the impact of functional and physical design changes on the life-cycle cost and determining key cost drivers. The ability to quickly estimate the cost impact of design changes is important for decision makers and serves as a medium of communication between customers and developers. Credible estimation is gained by intimately linking the axiomatic design framework to the already existing costing unit (or component) domain and providing design traceability. Development cost is predicted by determining the functional requirements (FRs) affected by a change in customer needs or constraints, then by determining the propagation of that change from FRs to design parameters (DPs) to costing units. The list of affected components and the magnitude of the impact on each component is found and then used to determine through a parallel iteration process model how much development labor will be necessary to implement those changes. The labor is directly related to development costs. A formal method to designing operations using axiomatic design is presented in this thesis. Operations exist due to the time-variant combinatorial complexity of FRs.
(cont.) Operations implement reinitialization procedures in order to maximize the probability of success of FRs. This provides the way that axiomatic design can derive operations and the related cost parameters. This information could then be plugged into the cost impact model of a design change to determine the list-of affected operations. A new method of estimating the change in cost parameters due to a design change will be the focus of future research. Two main forms of key cost drivers are identified: the most expensive FRs and design iteration. A method of mapping estimates from the costing unit domain to the FR-DP map is suggested in order to cost out FRs. Design iteration as a key cost driver can be seen from two points of view. Axiomatic design identifies small design ranges, coupling and imaginary complexity as contributors to cost. Design structure matrices identify the most iterative set of tasks in the development process and offer procedures to reduce or speed up the iteration.
by Peter Nicholas Jeziorek.
S.M.
Moser, Michele R., and K. Keen. "Collaborative Systems for Children with Complex Physical and Mental Health Needs." Digital Commons @ East Tennessee State University, 2004. https://dc.etsu.edu/etsu-works/4995.
Повний текст джерелаCarra, Giulia. "Evolution of urban systems : a physical approach." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS254/document.
Повний текст джерелаMore than 50 % of the world population lives in urban areas and this proportion is expected to increase in the coming decades. Understanding what governs the evolution of urban systems has thus become of paramount importance.This renewed interest combined with the availability of large-scale data, allows a glimpse into the dawn of a new science of cities, interdisciplinary and based on data.Recent studies have shown the existence of statistical regularities and scaling laws for several socio-economic indicators such as fuel consumption, average commuting distance, cost of infrastructure, etc., and despite several recent attempts, the theoretical understanding of these results empirically observed remains very partial. The purpose of this thesis is to obtain a simplified, out of equilibrium model of urban growth, based on a small number of important mechanisms and which provides quantitative predictions in agreement with empirical data. For this, we will draw on studies in quantitative geography and spatial economy and we will revisit some of these old models with a new approach that integrates the tools and concepts of physics
Case, Denise Marie. "Engineering complex systems with multigroup agents." Diss., Kansas State University, 2015. http://hdl.handle.net/2097/19045.
Повний текст джерелаComputing and Information Sciences
Scott A. DeLoach
As sensor prices drop and computing devices continue to become more compact and powerful, computing capabilities are being embedded throughout our physical environment. Connecting these devices in cyber-physical systems (CPS) enables applications with significant societal impact and economic benefit. However, engineering CPS poses modeling, architecture, and engineering challenges and, to fully realize the desired benefits, many outstanding challenges must be addressed. For the cyber parts of CPS, two decades of work in the design of autonomous agents and multiagent systems (MAS) offers design principles for distributed intelligent systems and formalizations for agent-oriented software engineering (AOSE). MAS foundations offer a natural fit for enabling distributed interacting devices. In some cases, complex control structures such as holarchies can be advantageous. These can motivate complex organizational strategies when implementing such systems with a MAS, and some designs may require agents to act in multiple groups simultaneously. Such agents must be able to manage their multiple associations and assignments in a consistent and unambiguous way. This thesis shows how designing agents as systems of intelligent subagents offers a reusable and practical approach to designing complex systems. It presents a set of flexible, reusable components developed for OBAA++, an organization-based architecture for single-group MAS, and shows how these components were used to develop the Adaptive Architecture for Systems of Intelligent Systems (AASIS) to enable multigroup agents suitable for complex, multigroup MAS. This work illustrates the reusability and flexibility of the approach by using AASIS to simulate a CPS for an intelligent power distribution system (IPDS) operating two multigroup MAS concurrently: one providing continuous voltage control and a second conducting discrete power auctions near sources of distributed generation.
Seevinck, Jennifer. "Emergence in interactive art." Thesis, University of Technology, Sydney, 2011.
Знайти повний текст джерелаVazquez, Montelongo Erik Antonio. "Computational Study of Intermolecular Interactions in Complex Chemical Systems." Thesis, University of North Texas, 2020. https://digital.library.unt.edu/ark:/67531/metadc1703283/.
Повний текст джерелаOppelstrup, Tomas. "Simulation of relaxation processes in complex condensed matter systems algorithmic and physical aspets /." Doctoral thesis, Stockholm : Kungliga Tekniska högskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-11574.
Повний текст джерелаGaither, Scott P. "Biological Water: A Brief Review of Hydration Dynamics using Complex Systems." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1532015941319059.
Повний текст джерелаGoryan, Alexander S. "Nuclear magnetic resonance studies on bentonite in complex mixed systems." Licentiate thesis, Luleå tekniska universitet, Industriell miljö- och processteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-18463.
Повний текст джерелаGodkänd; 2012; 20121011 (alegor); LICENTIATSEMINARIUM Ämne: Gränsytors kemi/Chemistry of Interfaces Examinator: Professor Oleg N. Antzutkin, Institutionen för samhällsbyggnad och naturresurser, Luleå tekniska universitet Diskutant: Professor emeritus Willis Forsling, Institutionen för samhällsbyggnad och naturresurser, Luleå tekniska universitet Tid: Onsdag den 5 december 2012 kl 13.00 Plats: C305, Luleå tekniska universitet
Quek, Hiok Chai. "The application of artificial intelligence techniques to the integrated control of complex dynamic physical systems." Thesis, Heriot-Watt University, 1990. http://hdl.handle.net/10399/924.
Повний текст джерелаPassey, Jr David Joseph. "Growing Complex Networks for Better Learning of Chaotic Dynamical Systems." BYU ScholarsArchive, 2020. https://scholarsarchive.byu.edu/etd/8146.
Повний текст джерелаGHATTAS, HELEN. "Managing complex product development projects : An analytical framework for complex product development." Thesis, KTH, Industriell Management, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-191093.
Повний текст джерелаIn recent years, products have become more complex in terms of connectivity, performance and functionality. Therefore, this study aims at studying how complex products are developed and managed through conducting multiple case studies at different Swedish companies that develop mechatronic or cyberphysical systems. The results of this study is the identification of many challenges that the investigated companies have, which have led to a presentation of an analytical framework that discusses how complex product development projects can and should be managed in order to be efficient, in order to reduce unnecessary complexity in the way companies develop these complex products.
Williamson, Daniel. "Policy making using computer simulators for complex physical systems : Bayesian decision support for the development of adaptive strategies." Thesis, Durham University, 2010. http://etheses.dur.ac.uk/348/.
Повний текст джерелаCarlsson, Gunilla. "Latex Colloid Dynamics in Complex Dispersions : Fluorescence Microscopy Applied to Coating Color Model Systems." Doctoral thesis, Karlstads universitet, Institutionen för kemi, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-2621.
Повний текст джерелаSinha, Rajib. "Systems Modeling Approaches to Physical Resource Management : An Industrial Ecology Perspective." Doctoral thesis, KTH, Industriell ekologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-191327.
Повний текст джерелаMånga nuvarande miljö- och utvecklingsproblem har uppstått som oförutsedda biverkningar av människans egna handlingar. De lösningar som prövats har i sin tur ofta skapat nya problem. Det därför viktigt att förstå hur komplexa system fungerar och att utforma styrmedel och ledningssystem som minimerar risken för oönskade bieffekter. Den här avhandling har använt olika modelleringsmetoder för att öka förståelsen för komplexa system och bidra med kunskaper om hur miljöprestanda och förvaltningsåtgärder kan följas upp på ett mer effektivt sätt. Det övergripande syftet med arbetet var att undersöka användbarheten av olika modelleringsmetoder för att effektivisera den fysiska resurshanteringen i samhället. I arbetet har ett flödesbaserat och aktörsinriktat arbetssätt (pressure based and driver oriented approach) använts i modelleringen. Material- och substansflödesanalys, miljöfotavtryck, input-output analys, processbaserad dynamisk modellering och systemdynamiska modelleringsmetoder studerades för att undersöka styrkor och svagheter hos de olika metoderna/verktygen. Tre olika modellerings- och redovisningsmetoder för att stödja miljöövervakning testades också i olika systemskalor. Statiska modelleringsmetoder (räkenskaper) identifierades som grundläggande för att kartlägga, kontoföra och övervaka den fysiska resursmetabolismen i produktions- och konsumtionssystem, medan dynamisk modellering visade sin styrka i att skapa förståelse för komplexa system. Resultaten pekar på att dynamiska modelleringsmetoder bör användas som ett komplement till statiska analyser för att förstå komplexiteten i systemen när man utformar och testar styrmedel. För att uppnå proaktiv övervakning bör flödesbaserade räkenskaper utnyttjas i större utsträckning i stället för den vanliga tillstånds- och påverkansövervakningen (state/impact monitoring). En viktig slutsats är därför att LCA-samfundet bör flytta fokus i sina bedömningar från påverkan till flöden.
QC 20160830
Asplund, Fredrik. "Risks Related to the Use of Software Tools when Developing Cyber-Physical Systems : A Critical Perspective on the Future of Developing Complex, Safety-Critical Systems." Doctoral thesis, KTH, Mekatronik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-152672.
Повний текст джерелаDen ökande komplexiteten och storleken på Cyber-Fysiska System (CPS) har lett till att produktiviteten i utvecklingen av CPS har minskat kraftigt. Krav på att CPS ska vara säkra att använda förvärrar problemet ytterligare, då dessa ofta är svåra att säkerställa och samtidigt av stor vikt för samhället. Mjukvaruverktyg, eller egentligen alla insatser för att automatisera utvecklingen av CPS, är en central komponent i många innovationer menade att lösa detta problem. Även om forskningen endast delvis studerat säkerhetsrelaterade konsekvenser av att automatisera produktutveckling, så är det känt att automation har haft en kraftig (och subtil) inverkan på operationella system. Om verktyg ska lösa problemet med en ökande komplexitet hos säkerhetskritiska CPS, så måste verktygens påverkan på produktutveckling, och i förlängningen på det säkra användandet av slutprodukterna, vara känd. Den här boken ger en översikt av forskningsfronten gällande säkerhetsrelaterade konsekvenser av verktygsanvändning. Denna kommer från en litteraturstudie i områdena systemsäkerhet, mjukvaruutveckling och verktygsintegration. Industriella säkerhetsstandarder identifieras som en viktig informationskälla. Då riskerna med användandet av enskilda verktyg har undersökts i stor utsträckning hos producenter av produkter relaterade till transport, studeras flera välkända säkerhetsstandarder från denna domän. Enligt de utvalda standarderna bör automation primärt utvärderas utifrån dess förmåga att självständigt utföra enskilda processteg på ett robust sätt. Automation som stödjer operatörers egna handlingar ses som tämligen oviktig. En konceptuell modell och en referensmodell har utvecklats baserat på litteraturstudien. Den förstnämnda definierar vilka entiteter och relationer som är av vikt för säkerhetsrelaterade konsekvenser av verktygsanvändning. Den sistnämnda beskriver olika aspekter av verktygsintegration och hur dessa relaterar till varandra. Genom att kombinera modellerna och utföra en riskanalys har egenskaper hos verktygskedjor som måste säkerställas för att undvika risk identifierats. Tio sådana säkerhetsrelaterade egenskaper beskrivs. Dessa säkerhetsrelaterade egenskaper möjliggör ett systematiskt sätt att begränsa vad som måste beaktas under studier av risker relaterade till verktygsanvändning. Hypotesen att ett stort antal faktorer relaterade till verktygsanvändning innebär risk kunde därför testas i en empirisk studie. Denna studie identifierade säkerhetsrelaterade svagheter i utvecklingsmiljöer knutna både till höga och låga nivåer av automation. Slutsatsen är att ett brett perspektiv, som inkluderar fler faktorer än de som beaktas av de utvalda standarderna, kommer att behövas i framtiden. Tre möjliga orsaker till att ett bredare perspektiv ändå skulle vara irrelevant analyseras, nämligen egenskaper specifika för CPS-domänen, egenskaper hos säkerhetskritiska CPS och möjligheten att lita på en beprövad, manuell process. Slutsatsen blir att ett bredare perspektiv är motiverat, och att den framtida utvecklingen av utvecklingsmiljöer för CPS sannolikt kommer att öka denna betydelse. Baserat på detta breda perspektiv läggs förslag fram för hur de mentala modellerna som bärs fram av de utvalda säkerhetstandarderna (och andra standarder som dem) kan utvecklas.
QC 20141001
Reta, Mañeru Daniel. "Understanding and predicting magnetic coupling in complex systems: from inorganic complexes to organic polyradicals." Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/380161.
Повний текст джерелаEsta tesis presenta un estudio teórico y computacional sobre la predicción precisa de constantes de acoplamiento magnético en una serie de sistemas complejos. Estos incluyen dos familias de compuestos principales. La primera familia está formada por complejos de coordinación inorgánicos, los cuales presentan centros magnéticos localizados sobre los átomos metálicos y estructuras cristalinas bien definidas. El segundo grupo se trata de radicales puramente orgánicos, con conjugación del sistema π, los cuales presentan una flexibilidad estructural mucho mayor y una deslocalización de los electrones desapareados más extensa. La tesis tiene dos partes principales. La primera se dedica a establecer una estrategia para la extracción de constantes de acoplamiento magnético, lo cual se lleva a cabo en una serie de complejos de coordinación heterodinucleares y homotrinucleares. La estrategia se basa la propuesta de una formulación alternativa del mapping approach, que evita el uso de un proyector de espín y con ello las deficiencias derivadas de ello, en comparación con la formulación inicial propuesta por Noodleman. Esta propuesta es aplicada al problema de tres-electrones tres-centros, y validada por comparación con el experimento y a través de le teoría del Hamiltoniano efectivo. La segunda parte de la tesis se centra en compuestos radicalarios puramente orgánicos π—conjugados, que presentan interacción entre los electrones desapareados a través de enlace. Con el objetivo de promover la estabilidad química de los centros radicalarios, diferentes unidades básicas son consideradas. En base a diferentes esquemas de acoplamiento de estas unidades, y del papel de la flexibilidad estructural, el principal objetivo es establecer los principales factores electrónicos y estructurales para aumentar la estabilidad del radical y promover una interacción ferromagnética robusta entre ellos. Las principales conclusiones de la tesis son dos: primero, la propuesta para extraer constantes de acoplamiento en sistemas complejos resulta en valores consistentes; segundo, esta tesis propone utilizar poliradicales lineales π-conjugados, basados en unidades moleculares derivados de poliarylmethyl radicales, para lograr propiedades ferromagnéticas robustas en sistemas puramente orgánicos estables.
Alestra, Tommaso. "Impacts of altered physical and biotic conditions in rocky intertidal systems: implications for the structure and functioning of complex macroalgal assemblages." Thesis, University of Canterbury. School of Biological Sciences, 2014. http://hdl.handle.net/10092/10025.
Повний текст джерелаNichol, Robert M. "THE INTERPRETATION OF ELECTRON ENERGY-LOSS SPECTROSCOPY IN COMPLEX SYSTEMS: A DFT BASED STUDY." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1431145968.
Повний текст джерелаGarcia, Leandro Martin Totaro. "Desenvolvimento de um modelo baseado em agentes para investigar a conformação e evolução de padrões populacionais de atividade física no lazer em adultos." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/6/6138/tde-29022016-141818/.
Повний текст джерелаIntroduction: Most of the actions to promote leisure-time physical activity at the population level has shown small or null effect sizes, or inconsistent results. Approaching the problem from a systemic perspective can be one way to overcome this gap. Objective: To develop an agent-based model to explore how the interaction between psychological traits and built and social environments leads to the formation and evolution of leisure-time physical activity population patterns in adults. Methods: The modeling process consisted of three stages: development of a conceptual map, based on literature review and expert-based consultation; creation and verification of the models algorithm; and parametrization and consistency and sensitivity analyses. The results of the literature review were consolidated and reported by search domain (psychological, social and built environment aspects). The quantitative results of the expert-based consultation were described using frequency and the content of the open ended questions were analyzed and compiled by the author. The models algorithm has been created using NetLogo, version 5.2.1., following a verification protocol to ensure that the algorithm has been implemented accurately. The Vargha-Delaney test, partial rank correlation coefficients, boxplots, and line and scatterplot graphs were used during the consistency and sensitivity analysis. Results: The elements of the conceptual map are the persons intention, the behavior of the persons social network and the community at large, and the perception of quality, access and available activities of places where leisure-time physical activity is practiced. The model is a hypothetical community with containing two types of agents: people and places where leisure-time physical activity is practiced. People interact with each other and with the built environment, generating population temporal trends of leisure-time physical activity and intention. Sensitivity analysis indicated that the temporal trends of leisure-time physical activity and intention are highly sensitive to the influence of the persons current behavior on her future intention, the persons perception radius size, and the proportion of places where leisure-time physical activity leisure is practiced. Final considerations: The conceptual map and the agent-based model are suitable to investigate the formation and evolution of leisure-time physical activity population patterns in adults. The influence of the persons behavior on her intention, the persons perception radius size, and the proportion of places where leisure-time physical activity leisure is practiced seem to be important determinants of the formation and evolution of population patterns of leisure-time physical activity in this model.
Возний, Андрій Петрович, Андрей Петрович Возный, Andrii Petrovych Voznyi, Ігор Володимирович Чернецький, Игорь Владимирович Чернецкий та Ihor Volodymyrovych Chernetskyi. "Логіко-методологічні проблеми тілесності людини в фізкультурно-спортивному концепті". Thesis, Сумський державний університет, 2020. https://essuir.sumdu.edu.ua/handle/123456789/79338.
Повний текст джерелаNemitz, Markus P. "HoverBot : a manufacturable swarm robot that has multi-functional sensing capabilities and uses collisions for two-dimensional mapping." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/33160.
Повний текст джерелаOliveira, Gonçalo Nuno de Pinho. "Local Probing Spinel and Perovskite Complex Magnetic Systems." Doctoral thesis, 2017. https://repositorio-aberto.up.pt/handle/10216/103096.
Повний текст джерелаOliveira, Gonçalo Nuno de Pinho. "Local Probing Spinel and Perovskite Complex Magnetic Systems." Tese, 2017. https://repositorio-aberto.up.pt/handle/10216/103096.
Повний текст джерела"VBOT: Motivating computational and complex systems fluencies with constructionist virtual/physical robotics." NORTHWESTERN UNIVERSITY, 2008. http://pqdtopen.proquest.com/#viewpdf?dispub=3307005.
Повний текст джерела(7456850), Babak Ravandi. "Analysis of Controllability for Temporal Networks." Thesis, 2019.
Знайти повний текст джерелаBhattacharya, Pallavi. "Theoretical Studies of Energy Transport in Complex Systems." Thesis, 2014. http://etd.iisc.ernet.in/2005/3509.
Повний текст джерела(8422929), Ivan Chio. "Some Connections Between Complex Dynamics and Statistical Mechanics." Thesis, 2020.
Знайти повний текст джерела(11113473), Cole R. Davis. "Relating the Formation Mechanisms and Kinetic Stability of Complex Shipboard Emulsions to the Physical and Chemical Properties of Model Surfactant-Oil-Water-Salt Systems." Thesis, 2021.
Знайти повний текст джерелаEmulsions are advantageous in many applications including healthcare, food science, and detergency due to their ability to disperse one fluid in another, otherwise immiscible fluid. For the same reason, emulsions are also problematic when mixtures of oil and water are undesirable like in industrial wastewater pollution and fuel systems. Whether an emulsion is desirable or not, both benefit from understanding the fundamental relationship of emulsion formation and stability to the physical and chemical properties of the oil-water-surfactant mixture. This work identifies the formation and stability mechanisms of model emulsion systems through the perspective of emulsion prevention for applications in shipboard wastewater (bilge water) treatment. Although experiments in this study were designed to model bilge water systems, their fundamental approach makes them practical for many different applications like food science, pharmaceuticals, and detergency.
The impact of salts on emulsion formation and stability to coalescence were studied to understand how emulsions stabilized by ionic surfactant behave in saltwater environments. Droplet size analysis revealed that emulsion stability to coalescence improved with salt concentration. Through interfacial tension and zeta potential measurements, it was found that the addition of salt promoted close surfactant packing and faster surfactant adsorption kinetics at the oil-water interface. This aided in preventing coalescence and created conditions favorable for the formation of a stable Newton black film. Extended DLVO calculations were used to model the interaction energy between droplets and suggested that hydration forces play an important role in stabilizing these systems. These emulsions were then studied under dynamic ageing conditions to observe the impact of motion on emulsion stability. While statically aged emulsions were stable to coalescence, dynamic ageing induced coalescence (increased droplet size) or emulsified the oil droplets (decreased droplet size) depending on the surfactant concentration and energy input during ageing.
Formation mechanisms and stability of spontaneous emulsion systems were also investigated. Low molecular weight oils (e.g., toluene, xylenes, and cyclohexane) were found to spontaneously emulsify with nonylphenol polyethoxylated (NPE) and sodium dodecylbenzene sulfonate (SDBS). NPE emulsions spontaneously emulsified via diffusion and micelle swelling and displayed limited stability due to Ostwald ripening. SDBS emulsions also spontaneously emulsified with toluene but only in saltwater environments. As the concentration of salt in the aqueous phase increased, the spontaneity of these emulsions also increased. These systems were analyzed using the hydrophilic lipophilic difference (HLD) theory to evaluate its efficacy for predicting the conditions favorable for spontaneous emulsification. Limitations and practicality of using the HLD model for these systems were also explored."Effect of Chaos and ComplexWave Pattern Formation in Multiple Physical Systems: Relativistic Quantum Tunneling, Optical Meta-materials, and Co-evolutionary Game Theory." Doctoral diss., 2012. http://hdl.handle.net/2286/R.I.15796.
Повний текст джерелаDissertation/Thesis
Ph.D. Electrical Engineering 2012
Larose-Filotas, Élise. "Structure et dynamique des communautés multi-espèces : le rôle de l’espace." Thèse, 2009. http://hdl.handle.net/1866/3161.
Повний текст джерелаThis thesis is a study of the role of space in the organization and dynamics of multi-species ecological communities. Two weaknesses can be identified from previous theoretical studies concerned with the spatial dimension of ecological communities: the scarcity of multi-species models based on a spatially explicit representation of space, and the lack of attention toward positive interspecific interactions, such as mutualism, despite the recognition of their ubiquity in ecological systems. This thesis explores this problematic by adopting a theoretical framework based on complex system theory and statistical mechanics. Following this approach, ecological communities can be viewed as complex systems whose global properties emerge from the local interactions between the organisms that composed them, and between the organisms and their environment. The first objective of this thesis is to develop a multi-species metacommunity model which is spatially explicit, individual-based, and centered on a general interspecific interaction web containing exploitation, competition as well as mutualism. In this model, local communities are created by an assembly process whereby species are drawn from a regional pool. Population growth is restricted by a carrying capacity and its dynamics is driven by simple reproduction and dispersal mechanisms acting at the level of single individual. These mechanisms depend on the biotic and abiotic conditions of the local communities and their effect varies with species, time and space. The second objective of this thesis is to determine the impact of an increasing spatial connectivity on the dynamics, and structural and functional properties of this metacommunity. More precisely, we set out to evaluate different community properties under changes in the level of species dispersal: i) the similarity in local community composition and its patterns of spatial correlations, ii) the local and regional diversity and the local species abundance, iii) the local and regional biomass, productivity and dynamical stability, and iv) the structure of the local interaction webs. These properties are examined under two spatial schemes. First, we employ a homogeneous environment, and second we employ a heterogeneous environment whereby the carrying capacity of local communities evolves along a gradient. In general, our results reveal that spatially distributed ecological communities are extremely sensitive to the modes and levels of species dispersal. Their spatiotemporal dynamics as well as their structural and functional properties can undergo profound changes in the form of significant transitions under slight changes of the level of dispersal. These changes are also highlighted by the emergence of spatiotemporal patterns in the spatial distribution of the populations, which are characteristics of phase transition generally observed in physical systems. The metacommunity presents two dynamical regimes. In the first regime, corresponding to weak levels of species dispersal, the assembly dynamics promotes the emergence of species-poor but stable communities made of abundant and strongly mutualistic species. The metacommunity has a high regional diversity since weakly connected communities conserve a distinct assemblage of species. On the other hand, in the second regime, corresponding to strong dispersal rates, regional diversity decreases at the benefit of an increase in local diversity. Local communities are more productive but their stability is reduced due to the important migration of individuals. This regime is also characterized by assemblages containing a richer diversity of interspecific interactions. These results suggest that an augmentation in the level of species dispersal permits organisms to couple local communities together which increases local coexistence and promotes the organization of richer and more complex ecological communities. Finally, our results suggest that mutualism is fundamental to the organization and persistence of ecological communities. Mutualistic species dominate in habitats characterized by a restricted carrying capacity and serve as ecological engineer by facilitating the establishment of competitors, predators and opportunists which benefit from their presence.