Dissertations / Theses on the topic 'Crop growth simulation modelling'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Crop growth simulation modelling.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
Florin, Madeleine Jill. "Towards Precision Agriculture for whole farms using a combination of simulation modelling and spatially dense soil and crop information." Thesis, The University of Sydney, 2008. http://hdl.handle.net/2123/3169.
Full textFlorin, Madeleine Jill. "Towards Precision Agriculture for whole farms using a combination of simulation modelling and spatially dense soil and crop information." University of Sydney, 2008. http://hdl.handle.net/2123/3169.
Full textPrecision Agriculture (PA) strives towards holistic production and environmental management. A fundamental research challenge is the continuous expansion of ideas about how PA can contribute to sustainable agriculture. Some associated pragmatic research challenges include quantification of spatio-temporal variation of crop yield; crop growth simulation modelling within a PA context and; evaluating long-term financial and environmental outcomes from site-specific crop management (SSCM). In Chapter 1 literature about managing whole farms with a mind towards sustainability was reviewed. Alternative agricultural systems and concepts including systems thinking, agro-ecology, mosaic farming and PA were investigated. With respect to environmental outcomes it was found that PA research is relatively immature. There is scope to thoroughly evaluate PA from a long-term, whole-farm environmental and financial perspective. Comparatively, the emphasis of PA research on managing spatial variability offers promising and innovative ways forward, particularly in terms of designing new farming systems. It was found that using crop growth simulation modelling in a PA context is potentially very useful. Modelling high-resolution spatial and temporal variability with current simulation models poses a number of immediate research issues. This research focused on three whole farms located in Australia that grow predominantly grains without irrigation. These study sites represent three important grain growing regions within Australia. These are northern NSW, north-east Victoria and South Australia. Note-worthy environmental and climatic differences between these regions such as rainfall timing, soil type and topographic features were outlined in Chapter 2. When considering adoption of SSCM, it is essential to understand the impact of temporal variation on the potential value of managing spatial variation. Quantifying spatiotemporal variation of crop yield serves this purpose; however, this is a conceptually and practically challenging undertaking. A small number of previous studies have found that the magnitude of temporal variation far exceeds that of spatial variation. Chapter 3 of this thesis dealt with existing and new approaches quantifying the relationship between spatial and temporal variability in crop yield. It was found that using pseudo cross variography to obtain spatial and temporal variation ‘equivalents’ is a promising approach to quantitatively comparing spatial and temporal variation. The results from this research indicate that more data in the temporal dimension is required to enable thorough analysis using this approach. This is particularly relevant when questioning the suitability of SSCM. Crop growth simulation modelling offers PA a number of benefits such as the ability to simulate a considerable volume of data in the temporal dimension. A dominant challenge recognised within the PA/modelling literature is the mismatch between the spatial resolution of point-based model output (and therefore input) and the spatial resolution of information demanded by PA. This culminates into questions about the conceptual model underpinning the simulation model and the practicality of using point-based models to simulate spatial variability. iii The ability of point-based models to simulate appropriate spatial and temporal variability of crop yield and the importance of soil available water capacity (AWC) for these simulations were investigated in Chapter 4. The results indicated that simulated spatial variation is low compared to some previously reported spatial variability of real yield data for some climate years. It was found that the structure of spatial yield variation was directly related to the structure of the AWC and interactions between AWC and climate. It is apparent that varying AWC spatially is a reasonable starting point for modelling spatial variation of crop yield. A trade-off between capturing adequate spatio-temporal variation of crop yield and the inclusion of realistically obtainable model inputs is identified. A number of practical solutions to model parameterisation for PA purposes are identified in the literature. A popular approach is to minimise the number of simulations required. Another approach that enables modelling at every desired point across a study area involves taking advantage of high-resolution yield information from a number of years to estimate site-specific soil properties with the inverse use of a crop growth simulation model. Inverse meta-modelling was undertaken in Chapter 5 to estimate AWC on 10- metre grids across each of the study farms. This proved to be an efficient approach to obtaining high-resolution AWC information at the spatial extent of whole farms. The AWC estimates proved useful for yield prediction using simple linear regression as opposed to application within a complex crop growth simulation model. The ability of point-based models to simulate spatial variation was re-visited in Chapter 6 with respect to the exclusion of lateral water movement. The addition of a topographic component into the simple point-based yield prediction models substantially improved yield predictions. The value of these additions was interpreted using coefficients of determination and comparing variograms for each of the yield prediction components. A result consistent with the preceding chapter is the importance of further validating the yield prediction models with further yield data when it becomes available. Finally, some whole-farm management scenarios using SSCM were synthesised in Chapter 7. A framework that enables evaluation of the long-term (50 years) farm outcomes soil carbon sequestration, nitrogen leaching and crop yield was established. The suitability of SSCM across whole-farms over the long term was investigated and it was found that the suitability of SSCM is confined to certain fields. This analysis also enabled identification of parts of the farms that are the least financially and environmentally viable. SSCM in conjunction with other PA management strategies is identified as a promising approach to long-term and whole-farm integrated management.
Artus, Sally. "VEGIGRO: a crop growth teaching model." Thesis, University of Nottingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.484201.
Full textSong, Yu. "Modelling and analysis of plant image data for crop growth monitoring in horticulture." Thesis, University of Warwick, 2008. http://wrap.warwick.ac.uk/2032/.
Full textGhaffari, Abdolali. "Application of geographical information systems (GIS) and crop simulation modelling in sustainable agriculture." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312108.
Full textBrowne, David John. "Modelling columnar and equiaxed growth." Thesis, University of Oxford, 2002. http://ora.ox.ac.uk/objects/uuid:3d8ae26b-e0b4-4d54-801d-4951705d53aa.
Full textGillett, A. G. "Modelling the response of winter wheat to different environments : a parsimonious approach." Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339658.
Full textMokoko-Mokeba, Michael Christian. "Computer simulation : modelling the dynamics of agrochemical sprays above and within a crop canopy." Thesis, University of Portsmouth, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310384.
Full textVianna, Murilo dos Santos. "Functional, structural and agrohydrological sugarcane crop modelling: towards a simulation platform for Brazilian farming systems." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/11/11152/tde-01082018-150704/.
Full textA cultura da cana-de-açúcar é a principal fonte de açúcar e a segunda maior fonte de biocombustíveis do mundo. O Brasil é o maior produtor mundial desde a década de 80 e atualmente representa metade da produção mundial, enquanto que ao mesmo tempo o etanol e a biomassa correspondem a mais de 15% da fonte de energia do país. Contudo, a produtividade comercial da cana-de-açúcar brasileira atingiu um limiar de cerca de 75 t ha-1 e para atender à crescente demanda de açúcar e etanol, a cultura expandiu-se fortemente para a região centro-oeste, onde a irrigação é obrigatória para manter os níveis de produção e diminuir riscos de quebra de safra. Para dar suporte a tomada de decisão e avanço científico sobre onde e como a cultura deve se expandir e/ou aumentar a produtividade, é necessária uma visão heurística do sistema agrícola brasileiro que pode ser traduzida matematicamente para um modelo de cultura. Desta forma, os efeitos do manejo e tipo de solo, variabilidade climática e fatores econômicos na produtividade de culturas agrícolas podem ser avaliados quantitativamente por meio de modelos de culturas baseados em processos (MBP). No entanto, em contraste a outras culturas, a cana-de-açúcar possui apenas dois MBPs disponíveis para usuários finais (DSSAT-CANEGRO e APSIM-Sugar) que requerem calibração e parametrização para melhor representar o sistema agrícola de cana-de-açúcar do Brasil. Portanto, este estudo teve como objetivo desenvolver, calibrar e avaliar diferentes abordagens de modelagem de culturas voltadas a produção de cana-de-açúcar no Brasil, para servir como ferramenta de tomada de decisão para o setor público e privado, auxilio no manejo da água e avaliação dos impactos nas mudanças climáticas. Portanto, uma nova versão do modelo baseado em processo de cana-de-açúcar (SAMUCA) foi desenvolvida para operar a nível de fitômeros, incluindo os efeitos no crescimento e desenvolvimento da cana com base na cobertura da palha no solo, competição por luz no processo de perfilhamento e acúmulo de sacarose com base nas relações fonte-dreno. O modelo foi incorporado em uma plataforma modular dedicada a simular o sistema solo-planta-atmosfera e manejo do sistema agrícola. Além disso, a versão anterior do SAMUCA também foi reestruturada e acoplada à plataforma agro-hidrológica SWAP (\"Soil, Water, Atmosphere and Plant\") com objetivo de aprimorar as simulações de balanço hídrico no solo e efeito no crescimento da cana-de-açúcar. Por fim, um Modelo Funcional-Estrutural de Plantas (MFEP) para a cana-de-açúcar foi desenvolvido integrando os principais componentes da cultura a nível de órgãos (fitômeros) com base em uma abordagem de fonte-dreno e um modelo robusto de radiação que foram introduzidos em uma plataforma de modelagem tridimensional (GroIMP). As três abordagens foram avaliadas e seu desempenho foi determinado com base em condições experimentais para diferentes regiões brasileiras. O desempenho da nova versão do modelo SAMUCA em experimento de longo prazo e em diferentes condições brasileiras foi satisfatório e os índices de concordância foram próximos de outros modelos de cana-de-açúcar amplamente utilizados (CANEGRO e APSIM-Sugar). Além disso, a plataforma de simulação de culturas modulada pode ser usada para hospedar mais modelos de culturas e integrar novas características do sistema de cultivo brasileiro. O acoplamento do modelo SWAP-SAMUCA foi realizado e apesar não apresentar melhorias expressivas no desempenho do modelo em simular os componentes da cultura (com erro médio quadrático [RMSE] 6% menor), a habilidade do modelo SWAP-SAMUCA em simular o teor de água no solo mostrou-se consideravelmente superior em comparação ao modelo original (RMSE 32% menor). O MFEP para cana-de-açúcar foi capaz de simular o desenvolvimento do dossel, o processo de perfilhamento e o acúmulo de sacarose ao nível de órgãos e planta de forma satisfatória. Além de sua capacidade em simular com precisão a interceptação da radiação por cada estrutura do dossel, podendo auxiliar na compreensão do processo de competição intraespecífica entre perfilhos, a estrutura do MFEP da cana-de-açúcar também pode ser usada no apoio à pesquisa focando os mecanismos de acúmulo de sacarose e translocação de açúcares bem como em estudos de consórcio em cana-de-açúcar, como têm sido realizado com sucesso para outras culturas nos últimos anos.
Chew, Yin Hoon. "Multi-scale whole-plant model of Arabidopsis growth to flowering." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/8008.
Full textThorp, Kelly R., Douglas J. Hunsaker, Kevin F. Bronson, Pedro Andrade-Sanchez, and Edward M. Barnes. "Cotton Irrigation Scheduling Using a Crop Growth Model and FAO-56 Methods: Field and Simulation Studies." AMER SOC AGRICULTURAL & BIOLOGICAL ENGINEERS, 2017. http://hdl.handle.net/10150/626603.
Full textDu, Lac Melchior. "Modelling and simulation of heterogeneous growth dynamics in bacterial populations using a novel multiphasic growth method." Thesis, University of Warwick, 2017. http://wrap.warwick.ac.uk/100879/.
Full textMira, Francisco Infante Fialho Caeiro. "Análise descritiva e modelação do crescimento e desenvolvimento do Miscanthus x giganteus no ano de instalação." Master's thesis, ISA/UTL, 2011. http://hdl.handle.net/10400.5/3992.
Full textA key strategy in tackling the issue of greenhouse gas emissions is associated with the replacement of fossil energies by renewable ones. This is why, in this context, the recent interest in using biomass as an energy source is increasing, mainly as biofuels - fuels originating from energy crops. The essay here presented is therefore central in this subject area, contributing to the study of an energy crop with high potential in our country, the Miscanthus x giganteus. The main goals of this dissertation include a propagation study of the species, the analysis of the crops growth in Portugal in the year of installation through a field experiment, and the development of a growth and crop productivity model in the year of crop installation. With regard to vegetative propagation Miscanthus x giganteus showed the best results when rhizomes with four internodes were used (larger fragments). In the growth analysis for the year of installation Miscanthus x giganteus showed a fast and effective establishment, reaching a productivity of 13.8 t ha-1. By modeling the culture‟s growth behavior it was possible to obtain a successful development and total biomass productivity model, wich showed reasonable results in several areas of the country with different agro-ecological conditions
Georgis, Kidane. "The effect of fertiliser management practices on soil organic matter production in the semi-arid areas : a field and modelling approach." Title page, contents and abstract only, 1997. http://web4.library.adelaide.edu.au/theses/09AFP/09afpg352.pdf.
Full textPuvvala, Bhanu Sai Kishore. "3-D Simulation of Multi Cells and Growth Model - A Case Study InCompuCell3D." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1542724057475403.
Full textSayginer, Osman. "Modelling and simulation of novel optoacoustic sensors for monitoring crack growth in pressure vessel steels." Doctoral thesis, Università degli studi di Trento, 2021. http://hdl.handle.net/11572/304021.
Full textBrogi, Cosimo [Verfasser], and Johan Alexander [Akademischer Betreuer] Huisman. "Geophysics-based soil mapping for improved modelling of spatial variability in crop growth and yield / Cosimo Brogi ; Betreuer: Johan Alexander Huisman." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2019. http://d-nb.info/1205315969/34.
Full textKim, D. H. "Modelling urban growth : towards an agent based microeconomic approach to urban dynamics and spatial policy simulation." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1380772/.
Full textMavromatis, Theodoros. "Impact of different methods of climate change scenario construction on the yield distributions of winter wheat using crop growth simulation models." Thesis, University of East Anglia, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361486.
Full textPersson, Tomas. "Modelling effects of Barley yellow dwarf virus on growth and yield of oats /." Uppsala : Dept. of Crop Production Ecology, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/200616.pdf.
Full textAynsley, M. "Modelling and simulation of mycelial growth in submerged culture with application to the fed-batch penicillin fermentation." Thesis, University of Newcastle Upon Tyne, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316130.
Full textPant, Sudeep Raj. "Mathematical and physical modelling of crack growth near free boundaries in compression." University of Western Australia. School of Civil and Resource Engineering, 2005. http://theses.library.uwa.edu.au/adt-WU2005.0139.
Full textWickens, Patricia Anne. "Growth and simulation modelling studies of rock-lobster (Jasus lalandii) and mussel (Aulacomya ater) populations and their interactions." Master's thesis, University of Cape Town, 1985. http://hdl.handle.net/11427/21934.
Full textThe availability of the ribbed mussel, Aulacomya ater is thought to be the most important factor influencing the growth rate of the commercial rocklobster, Jasus lalandii on the southern African west coast. A range of growth rates represented by von Bertalanffy growth curves is estimated for both A. ater and J. lalandii. Five models of differing complexity based on the age distributions of these populations are formulated with the main purpose of investigating optimal harvesting strategies for i, lalandii. Mussel and lobster single-species models are developed with constant recruitment, as is a lobster model incorporating a linear stock-recruitment relationship. Two models in which lobster growth is influenced by mussel availability are presented, one in which there is constant recruitment and the other having a linear stock-recruitment relationship for lobsters. Data are compiled for three areas of differing J. lalandii growth rates and A. ater biomass. Two are rock-lobster fishing grounds, the Cape Peninsula and Dassen Island at which there is a small and large benthic biomass and corresponding "slow" and "overall" estimates for rock-lobster growth, respectively. The third area is a rock-lobster sanctuary, Robben Island where there is a large benthic biomass and rock-lobsters grow at a "fast" rate. The mussel, lobster and lobster-mussel models assuming constant recruitment are used to examine the effects various parameters have on population si2e composition. Growth and predation have marked effects on the si2e structure of the prey population whereas the size composition of the predator population is greatly affected by growth and harvesting. The simplest of the four lobster models, the single-species constant recruitment model produced. the most practical management information. The lobster model incorporating a stock-recruitment relationship is unstable while the lobster-mussel model with constant recruitment requires finetuning. Only simulations of the Cape Peninsula fishing ground produced valid results using the lobster-mussel model with a stock-recruitment relationship. Based on the results of the most reliable models, three main conclusions about rock-lobster harvesting strategies are made. An increase in fishing pressure is unlikely to be commercially beneficial because of the resulting decrease in catch ·per unit effort. If opened to fishing, the Robben Island sanctuary is likely to produce a sustainable yield of at least 340 tons annually with a small reduction (7 %) in the size of this population. Although results differ from area to area according to growth and harvesting rates, reducing the minimum catchable size from the present 89 mm carapace length to 70 mm or 80 mm is predicted to give a better overall harvest. The more conservative estimate of 80 mm minimum catchable size may cause the least change to the ecosystem, possibly produce a catch of more marketable si2e and may guard against "recruitment overfishing".
Seidel, Sabine. "Optimal simulation based design of deficit irrigation experiments." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-100254.
Full textIn der heutigen Gesellschaft gibt es zunehmend Bedenken gegenüber übermäßigem Wasser- und Düngereinsatz in der Landwirtschaft. Eine hohe Wasserproduktivität kann jedoch durch geeignete Bewässerungspläne mit hohen landwirtschaftlichen Erträgen in Einklang gebracht werden. Die mit der weitverbreiteten Stickstoffdüngung einhergehende Gewässerbelastung aufgrund von Stickstoffauswaschung erfordert zudem ein effizientes Stickstoffmanagement. Eine entsprechende ressourceneffiziente Landbewirtschaftung bedarf präzise Kenntnisse der Bodenwasser- und Stickstoffdynamiken sowie des Pflanzenwasser- und Stickstoffbedarfs. Als leistungsfähige Werkzeuge zur Unterstützung bei der Optimierung von Bewässerungs-und Düngungsplänen werden Pflanzenwachstumsmodelle eingesetzt, welche die physischen und physiologischen Prozesse des Pflanzenwachstums sowie die physikalischen Prozesse des Wasser- und Stofftransports abbilden. Hierbei hängt die Zuverlässigkeit dieser simulationsbasierten Vorhersagen von der Qualität und Quantität der bei der Modellkalibrierung und -validierung verwendeten Daten ab, welche beispielsweise in Feldversuchen erfasst werden. Fehlende Daten oder Daten mangelhafter Qualität bei der Modellkalibrierung und -validierung führen zu unzuverlässigen Simulationsergebnissen und großen Unsicherheiten bei der Vorhersage. Die große Anzahl an zu kalibrierenden Parametern erfordert zudem geeignete Kalibrierungsmethoden sowie eine sequenzielle Kalibrierungsstrategie. Darüber hinaus kann eine simulationsbasierte Planung des Versuchsdesigns Kosten und Aufwand reduzieren und zu weiteren experimentellen Erkenntnissen führen. Die Abstimmung von Pflanzenwachstumsmodellen und Versuchen ist zudem für die Modellentwicklung und -verbesserung sowie für eine Verallgemeinerung von Simulationsergebnissen unabdingbar. Im Rahmen dieser Arbeit wurde ein neuer Ansatz für ein simulationsbasiertes optimales Versuchsdesign entwickelt. Ziel war es, Simulationsmodelle, Versuche und Optimierungsmethoden in einem Ansatz für optimales und nachhaltiges Bewässerungs- und Düngungsmanagement zu integrieren. Der Ansatz besteht aus drei Schritten: 1. Die Vorbereitungsphase beinhaltet die auf existierenden Versuchsdaten basierende Kalibrierung und Validierung des Pflanzenwachstumsmodells, die Generierung von Klimazeitreihen und die Bestimmung der optimalen Bewässerungssteuerung. 2. Die Durchführungsphase setzt sich aus der Erstellung und experimentellen Anwendung der simulationsbasierten optimierten Defizitbewässerungs- und Stickstoffdüngungspläne und der Erfassung der relevanten Versuchsdaten zusammen. 3. Die Auswertungsphase schließt eine Evaluierung der Versuchsergebnisse anhand ermittelter Erträge, Wasserproduktivitäten (WP), Stickstoffnutzungseffizienzen (NUE) und ökonomischer Aspekte, sowie eine Modellevaluierung ein. In dem neuen Ansatz kamen im Wesentlichen folgende fünf Werkzeuge zur Anwendung: Ein Algorithmus zur inversen Modellparametrisierung, ein Pflanzenwachstumsmodell, welches das Pflanzenwachstum sowie die Wasser- und Stickstoffbilanzen abbildet, ein evolutionärer Optimierungsalgorithmus für die Generierung von defizitären Bewässerungs- und Stickstoffplänen und ein stochastischer Wettergenerator. Zudem diente ein Bodenwasserströmungsmodell der Ermittlung der optimalen Bewässerungssteuerung und der simulationsbasierten Optimierung des Versuchsdesigns. Der in dieser Arbeit vorgestellte Ansatz wurde in drei Fallbeispielen angewandt. Der neue Ansatz kombiniert Pflanzenwachstumsmodellierung und Experimente mit stochastischer Optimierung. Er leistet einen Beitrag zu einer erfolgreichen Pflanzenwachstumsmodellierung basierend auf der Erfassung relevanter Versuchsdaten. Die vorgestellte Modellkalibrierung und -validierung unter Verwendung der erfassten Versuchsdaten trug wesentlich zu zuverlässigen Simulationsergebnissen bei. Darüber hinaus stellt die hier vorgestellte stochastische Optimierung von defizitären Bewässerungs- und Stickstoffplänen ein leistungsfähiges Werkzeug dar, um Erträge, WP, NUE und den Profit zu erhöhen
Sistla, Sree Koundinya [Verfasser]. "Numerical Modelling and Simulation of Temperature Fields, Densification and Grain Growth during Field Assisted Sintering Technology / Sree Koundinya Sistla." Düren : Shaker, 2021. http://d-nb.info/1240853653/34.
Full textPötschke, Markus. "Simulation of electric field-assisted nanowire growth from aqueous solutions." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-194735.
Full textZiel der vorliegenden Arbeit ist es, mittels physikalischer und chemischer Modelle die Mechanismen des Nanodrahtwachstums aus wässrigen Lösungen zu erforschen und daraus eine optimierte Prozesskontrolle abzuleiten. Dabei werden zwei Verfahren des Nanodrahtwachstums näher betrachtet: Dies sind die dielektrophoretische Assemblierung von neutralen Molekülen oder Metallclustern sowie die gerichtete elektrochemische Nanodrahtabscheidung (engl. directed electrochemical nanowire assembly), bei der metallhaltige Ionen im elektrischen Wechselfeld an der Nanodrahtspitze zunächst reduziert und anschließend als Metallatome abgeschieden werden. Zur Beschreibung der Transport- und Wachstumsprozesse werden Kontinuumsmodelle eingesetzt. Darüber hinaus hat es sich als notwendig erwiesen, elektrokinetische Fluidströmungen zu berücksichtigen, um die experimentellen Beobachtungen zu reproduzieren. Die auftretenden partiellen Differenzialgleichungen werden mittels der Finiten Elemente Methode (FEM) numerisch gelöst. Die Auswirkungen der Prozessparameter auf das Nanodrahtwachstum werden durch den Vergleich von experimentellen Ergebnissen mit Parameterstudien analysiert. Die Auswertung hat ergeben, dass für das dielektrophoretische Wachstum ein durch Wechselfeldelektroosmose (engl. AC electro-osmosis) angetriebener Fluidstrom die Drahtwachstumsgeschwindigkeit und -morphologie maßgeblich beeinflusst. Im Falle der gerichteten elektrochemischen Nanodrahtabscheidung lässt sich die Drahtmorphologie über das angelegte elektrische Wechselsignal steuern. Unter Verwendung des Wachstumsmodells ist ein optimiertes Signal generiert worden, dessen Parametrisierung eine gezielte Anpassung auf den chemischen Ausgangsstoff und den gewünschten Drahtdurchmesser erlaubt
Prats, Soler Clara. "Individual-based modelling of bacterial cultures in the study of the lag phase." Doctoral thesis, Universitat Politècnica de Catalunya, 2008. http://hdl.handle.net/10803/6590.
Full textL'objectiu d'aquest treball és millorar la comprensió de la fase de latència dels cultius bacterians i dels fenòmens intrínsecs a la mateixa. Aquest objectiu s'ha abordat amb la metodologia Individual-based Modelling (IbM) amb el simulador INDISIM (INDividual DIScrete SIMulation), que ha calgut optimitzar. La IbM introdueix una perspectiva mecanicista a través de la modelització de les cèl·lules com a unitats bàsiques. Les simulacions IbM permeten estudiar el creixement d'entre 1 i 106 bacteris, així com els fenòmens que emergeixen de la interacció entre ells. Aquests fenòmens pertanyen al que anomenem escala mesoscòpica. Aquesta perspectiva és imprescindible per entendre l'efecte en la població dels processos d'adaptació individuals. Per tant, la metodologia IbM és un pont entre els individus i la població o, el que és el mateix, entre els models a escala microscòpica i a escala macroscòpica.
En primer lloc hem estudiat dos dels diversos mecanismes que poden causar la fase de latència: inòculs amb massa mitjana petita, i canvis de medi.
S'ha verificat també la relació de la durada de la latència amb variables com la temperatura o la grandària de l'inòcul. En aquest treball s'ha identificat la distribució de biomassa del cultiu com una variable cabdal per analitzar l'evolució del cultiu durant el cicle de creixement. S'han definit les funcions matemàtiques que anomenem distàncies per avaluar quantitativament l'evolució d'aquesta distribució.
Hem abordat, també, la fase de latència des d'un punt de vista teòric. L'evolució de la velocitat de creixement al llarg del cicle ha permès distingir dues etapes en la fase de latència que anomenem inicial i de transició. L'etapa de transició s'ha descrit per mitjà d'un model matemàtic continu validat amb simulacions INDISIM. S'ha constatat que la fase de latència ha de ser vista com un procés dinàmic, i no com un simple període de temps descrit per un paràmetre. Les funcions distància també s'han utilitzat per avaluar les propietats del creixement balancejat.
Alguns dels resultats de les simulacions amb INDISIM s'han corroborat experimentalment per mitjà de citometria de flux. S'ha comprovat, al llarg de les diverses fases del creixement, el comportament de la distribució de biomassa previst per simulació, així com l'evolució de les funcions distància. La coincidència entre els resultats experimentals i els de simulació no és trivial, ja que el sistema estudiat és molt complex. Per tant, aquests resultats permeten comprovar la bondat de la metodologia INDISIM.
Finalment, hem avançat en l'optimització d'eines per parametritzar IbMs, un pas essencial per poder utilitzar les simulacions INDISIM de manera quantitativa. S'han adaptat i assajat els mètodes grid search, NMTA i NEWUOA. Aquest darrer mètode ha donat els millors resultats en termes de temps, mantenint una bona precisió en els valors òptims dels paràmetres.
Per concloure, podem afirmar que INDISIM ha estat validat com una bona eina per abordar l'estudi dels estats transitoris com la fase de latència.
Predictive food microbiology has become an important specific field in microbiology. Bacterial growth of a batch culture may show up to four phases: lag, exponential, stationary and death. The bacterial lag phase, which is of specific interest in the framework of predictive food microbiology, has generally been tackled with two generic approaches: at a cellular and intracellular level, which we call the microscopic scale, and at a population level, which we call the macroscopic scale. Studies at the microscopic level tackle the processes that take place inside the bacterium during its adaptation to the new conditions such as the changes in genetic expression and in metabolism.
Studies at the macroscopic scale deal with the description of a population growth cycle by means of mathematical continuous modelling and experimental measurements of the variables related to cell density evolution.
In this work we aimed to improve the understanding of the lag phase in bacterial cultures and the intrinsic phenomena behind it. This has been carried out from the perspective of Individual-based Modelling (IbM) with the simulator INDISIM (INDividual DIScrete SIMulation), which has been specifically improved for this purpose. IbM introduces a mechanistic approach by modelling the cell as an individual unit. IbM simulations deal with 1 to 106 cells, and allow specific study of the phenomena that emerge from the interaction among cells. These phenomena belong to the mesoscopic level.
Mesoscopic approaches are essential if we are to understand the effects of cellular adaptations at an individual level in the evolution of a population.
Thus, they are a bridge between individuals and population, or, to put it another way, between models at a microscopic scale and models at a macroscopic scale.
First, we studied separately two of the several mechanisms that may cause a lag phase: the lag caused by the initial low mean mass of the inoculum, and the lag caused by a change in the nutrient source. The relationship among lag duration and several variables such as temperature and inoculum size were also checked.
This analysis allowed identification of the biomass distribution as a very important variable to follow the evolution of the culture during the growth cycle. A mathematical tool was defined in order to assess its evolution during the different phases of growth: the distance functions.
A theoretical approach to the culture lag phase through the dynamics of the growth rate allowed us to split this phase into two stages: initial and transition. A continuous mathematical model was built in order to shape the transition stage, and it was checked with INDISIM simulations. It was seen that the lag phase must be defined as a dynamic process rather than as a simple period of time. The distance functions were also used to discuss the balanced growth conditions.
Some of the reported INDISIM simulation results were subjected to experimental corroboration by means of flow cytometry, which allow the assessment of size distributions of a culture through time. The dynamics of biomass distribution given by INDISIM simulations were checked, as well as the distance function evolution during the different phases of growth.
The coincidence between simulations and experiments is not trivial: the system under study is complex; therefore, the coincidence in the dynamics of the different modelled parameters is a validation of both the model and the simulation methodology.
Finally, we have made progress in IbM parameter estimation methods, which is essential to improve quantitative processing of INDISIM simulations.
Classic grid search, NMTA and NEWUOA methods were adapted and tested, the latter providing better results with regard to time spent, which maintains satisfactory precision in the parameter estimation results.
Above all, the validity of INDISIM as a useful tool to tackle transient processes such as the bacterial lag phase has been amply demonstrated.
Llopart, Prieto Llorenç. "Modelling And Analysis Of Crack Turning On Aeronautical Structures." Doctoral thesis, Universitat Politècnica de Catalunya, 2007. http://hdl.handle.net/10803/6055.
Full textDurant aquest treball s'ha demostrat la importància i necessitat de caracteritzar el camp de tensions a la punta de l'esquerda amb el factor d'intensitat de tensió (SIF) conjuntament amb un segon paràmetre. La tensió uniforme, no singular, normal a la línea de l'esquerda i dependent en la geometria i càrrega de la proveta, es a dir la tensió T, ha estat seleccionada com a segon paràmetre per dur a terme les prediccions del gir d'esquerda.
El criteri més desenvolupat per predir el gir d'esquerda en situacions pròximes a Mode I és el proposat per Buczek, Herakovich, Boone et al., anomenat WEFO en la tesis. Aquest combina el criteri de tensió principal màxima amb la tensió T i considera efectes d'anisotropia.
LEFM s'ha utilitzat també en la predicció del gir d'esquerda sota càrregues quasi estàtiques controlant en tot moment la plastificació del lligament.
En la investigació d'eines de modelització/simulació s'ha tingut en compte les capacitats d'aquestes en el camp de la mecànica de la fractura, de disseny, d'implementació, així com la complexitat d'ús. Tot i que hi ha un gran ventall de Softwares que compleixen els requeriments assenyalats, només aquells que es trobaven a l'abast de l'autor s'han analitzat. StressCheck ha estat escollit com a resultat de la investigació. L'avaluació de la propagació de l'esquerda en provetes compactes en tensió (CT) i en provetes amb dos elements reforçants (2SP) sota els règims de Paris i Forman ha estat satisfactòria.
Un pas important ha estat la implementació de la capacitat d'extracció de la tensió T. La demostració de la fiabilitat en el seu càlcul s'ha demostrat mitjançant resultats en la literatura i càlculs analítics en provetes de doble biga en volada (DCB). Un aspecte a tenir en compte és la importància en realitzar anàlisis no linears geomètrics pel càlcul del SIF i la tensió T.
Prediccions en la trajectòria de l'esquerda s'han realitzat en base amb els resultats obtinguts en l'estudi de modelització. La millor trajectòria s'ha predit per mitjà del criteri WEFO. No obstant, les diferents trajectòries obtingudes per una esquerda propagant-se en la direcció T-L o L-T no són comparables amb els resultats experimentals.
Aquestes deficiències estan relacionades en la definició del punt d'inestabilitat de l'esquerda. Algunes referències posen de manifest que hi ha experiències on l'esquerda es comporta de forma estable tot i mostrar T > 0. Per un altre banda, els criteris WEF i WEFO defineixen la inestabilitat dependent d'una distancia específica del material, rc. Però la seva definició no és única i no existeix cap acord sobre el seu càlcul.
L'autor proposa un criteri derivat dels criteris existents i basant-se en els assajos, simulacions i resultats obtinguts. Aquest deriva del treball de Pettit i la tensió T normalitzada, TR, proposada per Pook.
La fiabilitat d'aquest criteri es demostra amb la proveta DCB. Les prediccions de la trajectòria de l'esquerda en la proveta cruciforme no són tant satisfactòries. Tot i així, s'ha d'accentuar que el criteri desenvolupat proporciona la predicció més acurada.
The motivation of this thesis started from the interest of aeronautical industry to exploit the utilization of crack turning to protect stiffeners in front of an approaching skin-crack in integral structures by a tailored design. The main objective was to assess and predict crack turning under nearly Mode I situations on structures that reproduce aeronautical conditions by providing a modelling tool and a reliable criterion. The industrial environmental in which this work has been carried out requires a fast prediction of the structural behaviour to provide useful inputs to aircraft designers. It is for this reason that the crack turning prediction was investigated by means of LEFM and FEA.
During this work it has been shown the importance and necessity of a second parameter for the characterisation of the stress field at the crack tip besides the SIF. Among the different proposed second parameters, the uniform non-singular stress, normal to the crack line and dependent on the type of loading and specimen geometry, i.e. the T-stress, was selected for crack turning predictions due to both calculation simplicity and its independence of the crack tip distance.
The most developed criterion for crack turning predictions near Mode I loading is the criterion proposed by Buczek, Herakovich and Boone et al., called the WEFO-criterion. This is the Maximal Principal Stress criterion implemented with the T-stress and taking into account anisotropic effects. A challenge of this thesis was to overcome the lack of prediction on crack turning provided by this last criterion.
Although the validity of LEFM is restricted, it was applied for the prediction of crack turning for quasi-static loading while paying attention to possible plastification.
A screening of existent commercial and non commercial tools was carried out in respect to their fracture mechanics capabilities, their design abilities, implementation as well as their complexity. Although, there are many software possibilities, only those within the reach of the author were evaluated. This resulted in the selection of the commercial tool StressCheck®. The assessment of crack propagation on compact tension and two stringer specimens governed by the Paris and Forman regimes was satisfactory compared with experimental results using the material data from simple standard specimens.
An important step was the implementation of the T-stress extraction facility in the tool and the evidence of its reliability. The latter was proved by literature and analytical calculations on DCB specimens. An important finding was the importance to perform geometric non-linear analyses for computing SIF and T-stress to find values comparable with literature data and analytical calculations.
Taking into account the results obtained on the modelling study, crack path predictions were performed. The best prediction by means of existing criteria was reached by the WEFO-criterion. Different crack paths were predicted for a crack propagating in T-L or L-T directions. However, these predictions were not satisfactorily reliable: the point in the crack path where crack turning should take place was not predicted adequately.
Additionally, the crack paths were similar for T L and L-T directions.
These deficiencies are related with the definition of the crack path instability.
Some literature results have shown that in some experiences the crack behaved in a stable manner even if T > 0. Moreover, WEF and WEFO criteria define crack instability to be related with a material specific distance, rc, but, there is no agreement about its definition.
Based on tests, simulation results and observations noted during this work, a compilation criterion was proposed. This is based on the work of Pettit and the normalised T-stress, TR, proposed by Pook.
Its reliability was successfully proved on the DCB. The crack path predictions on the CFS were not as satisfactory. But even at its worst the developed criterion was the most accurate.
Kloß, Sebastian. "Simulation-Optimization of the Management of Sensor-Based Deficit Irrigation Systems." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-188762.
Full textQi, Rui. "Optimization and optimal control of plant growth : application of GreenLab model for decision aid in agriculture." Phd thesis, Châtenay-Malabry, Ecole centrale de Paris, 2010. http://tel.archives-ouvertes.fr/tel-00494918.
Full textScarpare, Fábio Vale. "Simulação do crescimento da cana-de-açucar pelo modelo agrohidrológico SWAP/WOFOST." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/11/11131/tde-12092011-172246/.
Full textSimulation models have been used in agricultural and ecological studies as a research tool allowing to organize and comprehend crop response under different environmental conditions, and to predict crop yield. The successful application of models depends on its calibration and assessment performed through morphophysiological index estimation and technological parameters of crop yield. The aims of this study were: to use the combination of a hydrological model (SWAP, Soil Water Atmosphere and Plant) with a generic crop growth model (WOFOST, WOrld FOod STudies) adapted to the sugarcane crop; to use PEST software (Parameter ESTimation) to calibrate and perform the sensitivity analysis of the model parameters; to appraise the model efficiency in estimating fresh weight of cane stems per hectare (TCH) and also to evaluate the effectiveness of the model when estimating soil hydraulic properties generated by pedotransfer functions (PTFs). Experimental data from SP 81-3250 cultivar were used for calibration (4 production cycles: first year cane and 3 ratoons at Santa Adélia sugarcane mill planting area), sensitivity analysis (first year cane at Santa Adélia sugarcane mill planting area) and validation (8 production cycles: 2 first year cane and 6 ratoons at two other sugarcane mill planting areas). Average yield from 25 cultivars grown among 10 different sites in Brazilian South-Central region were used to evaluate the model efficiency on yield prediction. The root mean square error (RMSE), coefficient of determination (R2), index of agreement (d) and coefficient of efficiency (E) were used to evaluate these procedures comparing above ground dry weight simulated by the model versus dry weight measured on the field. Good results were obtained during calibration and validation procedure; hence we may conclude that the SWAP/WOFOST model was able to predict sugarcane above ground dry weight. Model sensitivity analysis showed the group of CO2 assimilation parameters to be the most relevant determining final biomass. PEST software was effective in optimizing the hydraulic parameters by comparing the soil water content simulated by the model against water content measured on the field by the gravimetric method. TCH forecasts made by SWAP/WOFOST showed a similar RMSE as those obtained with the APSIMSugarcane model. However, evaluated by other statistical indexes, the SWAP/WOFOST model performance was intermediate. The model efficiency to simulate the above ground dry weight in crop cycles, first year cane and ratoon, was not affected when the hydraulic input parameters were generated by PTFs.
Abi, Saab David. "Propriétés optiques, mécanismes de formation et applications du silicium noir." Thesis, Paris Est, 2015. http://www.theses.fr/2015PESC1001/document.
Full textIn this thesis, we present a general overview of silicon micro and nanostructured surfaces, known as black silicon (BSi), fabricated with cryogenic deep reactive ion etching (cryo-DRIE). These self-generated surfaces can be fabricated in a single step procedure and provide large surfaces with reduced reflectance over a broad range of wavelengths and angles of incidence. We review several aspects of BSi surfaces, such as its fabrication methods, applications, topography characterization methods, modelling techniques for optical simulations, and growth mechanisms. We then develop three main contributions that this thesis brings to the state of the art: a better understanding of BSi topography, modelling of its optical behaviour and insights into its formation mechanism. We develop a novel BSi topographical characterisation technique which is based on in-plane focused ion beam nanotomography and can reproduce sample details with submicron accuracy. We then present different methods of modelling BSi unit cells, based either on real surface topography obtained using the aforementioned technique, or on equivalent geometric shapes that are statistically representative for BSi topography. We are capable to obtain excellent matching between simulations and experimental data. Finally, we present an experimentally-backed phenomenological model that is capable of simulating the entire evolution of a surface from a planar substrate to fully developed BSi topography. We produce a phase diagram which captures the parameter combinations responsible for BSi formation. We also observe experimentally, and are able to reproduce within our model, a number of subtle effects that lead to the observed pattern densification that is responsible for BSi formation during cryo-DRIE
Detomini, Euro Roberto. "Atributos ecofisiológicos do híbrido DKB-390 e modelo estocástico para previsão da produtividade de grãos." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/11/11143/tde-15072008-140048/.
Full textMaize is on of the world most important crops, given that the products generated from this cereal are largely used by sectors like starch industry, animal and human nutrition, as well as biomass energy production and refineries. For these reasons, there is frequently a huge interest in knowing the potential adoption of the main available genotypes in relation to the environment in which they will be supposedly subjected. Considering the hybrid DKB-390 under full irrigated conditions, this work has as the central objective to characterize the most important ecophysiological attributes such as leaf area, radiation use efficiency, extinction coefficient, crop coefficients, water use and ear yield components. Additionaly, specif goals were to conceptualize models applicable for both management and planning of maize crops in order to predict the grain productivity contemplated by daily climate incertainties of the driven climate variables (i.e. radiation and temperature) and their correlation, then to achieve the water and nitrogen requirement corresponding to the predicted productivity. A field experiment was carried out, useful information from literature were obtained and reviewed, and models were created towards to support the prediction tools. The following outcomes might be highligthed: (i) under suitable conditions of both nitrogen and water supply, hybrid DKB-390 requires about 573 litters of water per each kilogram of produced grain; (ii) the genotype is significantly responsive to the second nitrogen covering when growing under high plant population and suitable water supply; (iii) the second nitrogen covering has enhanced better leaf area maintainance during grain filling stage; (iv) the second nitrogen covering has led to a better water use efficiency, as well as slightly increased modal values of the number of kernels per row (of ear) and the mass of a thousand kernels; (v) under suitable water supply, averaged extinction coefficient might be generalized as 0.4267 throughout the whole cycle, whereas tending to be higher as the nitrogen supply is restricted; (vi) the radiation use efficiency as calculated as 3.52 g (above-ground dry matter) MJ-1 (intercepted photossyntheticaly active radiation), being smaller as the nitrogen supply is restricted; (vii) some crop coefficients were found for the main phenological stages and may be adopted for irrigation management of hybrid DKB-390, when one aims to not deplet the productivity; (viii) the harvest index (above-ground based) was found about 40% (varying from 37% to 43%) if water and nitrogen are added sufficiently, and is likely to be higher provided that the second covering is not done; (ix) the proposed determinist model has performed well when simulating above-ground dry matter time course and its corresponding grain productivity under full and moderated water deficit conditions; (x) by using Penman-Montheit method, the deterministic model apparently simulates well both daily evapotranspiration and water uses; (xi) through bivariate normal distribution of averaged daily solar radiation and air temperature, the suggested stochastic model has simulated grain productivity in a satisfactory way; and (xii) the suggested stochastic model need to be improved in terms of its water and nitrogen requirement predictability, given that it clearly tends to underestimate the former and overestimate the latter.
Perez, Raphaël. "Analyzing and modelling the genetic variability of aerial architecture and light interception of oil palm (Elaeis guineensis Jacq)." Thesis, Montpellier, SupAgro, 2017. http://www.theses.fr/2017NSAM0001/document.
Full textIn this study we proposed to investigate the influence of oil palm architecture on the capacity of the plant to intercept light, by using 3D reconstructions and model-assisted evaluation of radiation-use efficiency. The first objective of this study was to analyse and model oil palm architecture and light interception taking into account genetic variability. A second objective was to explore the potential improvements in light capture and carbon assimilation by manipulating oil palm leaf traits and propose architectural ideotypes.Allometric relationships were applied to model these traits according to ontogenetic gradients and leaf position within the crown. The methodology allowed reconstructing virtual oil palms at different stages over plant development. Additionally, the allometric-based approach was coupled to mixed-effect models in order to integrate inter and intra progeny variability through progeny-specific parameters. The model thus allowed simulating the specificity of plant architecture for a given progeny while including observed inter-individual variability. The architectural model, parameterized for the different progenies, was then implemented in AMAPstudio to generate 3D mock-ups and estimate light interception efficiency, from individual to stand scales.Significant differences in leaf geometry (petiole length, density of leaflets and rachis curvature) and leaflets morphology (gradients of leaflets length and width) were detected between and within progenies, and were accurately simulated by the modelling approach. Besides, light interception estimated from the validated 3D mock-ups showed significant variations among the five progenies.Sensitivity analyses were then performed on a subset of architectural parameters to identify the architectural traits impacting on light interception efficiency and potential carbon assimilation over plant development. The most sensitive parameters over plant development were those related to leaf area (rachis length, number of leaflets, leaflets morphology), but fine attribute related to leaf geometry showed increasing influence when canopy got closed. In adult stand, optimized carbon assimilation was estimated on plants presenting a leaf area index (LAI) between 3.2 and 5.5 m2.m−2, with erected leaves, short rachis and petiole and high number of leaflet on rachis. Four architectural ideotypes for carbon assimilation were proposed based on specific combinations of organs geometry, limiting mutual shading and optimizing light distribution within plant crown.In conclusion, this study highlighted how a functional-structural plant model (FSPM) can be used to virtually explore plant biology. In our case of study, the 3D model of oil palm, in its conception and its application, permitted to detect the architectural traits genetically determined and influencing light interception. The limited number of traits revealed in the sensitivity analysis and the combination of traits proposed through ideotypes could guide further breeding programs. Forthcoming work will be dedicated to integrate in the modeling approach other physiological processes such as stomatal conductance and carbon partitioning. The improved FSPM could then be used to test different scenarios, for instance in climate change context with low radiations or frequent drought events. Similarly, the model could be used to investigate different planting patterns and intercropping systems, and proposed new multi-criteria ideotypes of oil palm
Harena, Tchamse. "Essai de validation et perspectives d'application en agrometeorologie d'un modele de simulation de la croissance et du developpement du mais : ceres-maize." Clermont-Ferrand 2, 1988. http://www.theses.fr/1988CLF2D214.
Full textBates, Andrew John. "Effects of grazing management and pasture composition on the nitrogen dynamics of a dairy farm : a simulation analysis : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Lincoln University /." Diss., Lincoln University, 2009. http://hdl.handle.net/10182/1360.
Full textCorreia, António. "Influence of Tissue Mechanics in Blood Vessel Growth." Master's thesis, 2012. http://hdl.handle.net/10316/21062.
Full textThis work is financed by FEDER Funds through the Programa Operacional Fatores de Competitividade – COMPETE and by National Funds through FCT – Fundação Para a Ciência e a Tecnologia in the scope of project FCOMP-01-0124-FEDER-015708.
"Mathematical Modelling and Computational Simulation of in vitro Tissue Culture Processes." Thesis, 2015. http://hdl.handle.net/10388/ETD-2015-07-2131.
Full textPalmer, Ian J., Chen Wang, and Tao Ruan Wan. "A Real-time Dynamic Simulation Scheme for Large-Scale Flood Hazard Using 3D Real World Data." 2007. http://hdl.handle.net/10454/2891.
Full textWe propose a new dynamic simulation scheme for large-scale flood hazard modelling and prevention. The approach consists of a number of core parts: Digital terrain modelling with GIS data, Nona-tree space partitions (NTSP), Automatic River object recognition and registration, and a flood spreading model. The digital terrain modelling method allows the creation of a geometric real terrain model for augmented 3D environments with very large GIS data, and it can also use information gathered from aviation and satellite images with a ROAM algorithm. A spatial image segmentation scheme is described for river and flood identification and for a 3D terrain map of flooding region growth and visualisation. The region merging is then implemented by adopting Flood Region Spreading Algorithm (FRSA). Compared with the conventional methods, our approach has the advantages of being capable of realistically visualising the flooding in geometrically-real 3D environments, of handling dynamic flood behaviour in real-time and of dealing with very large-scale data modelling and visualisation.
Pötschke, Markus. "Simulation of electric field-assisted nanowire growth from aqueous solutions." Doctoral thesis, 2014. https://tud.qucosa.de/id/qucosa%3A29190.
Full textZiel der vorliegenden Arbeit ist es, mittels physikalischer und chemischer Modelle die Mechanismen des Nanodrahtwachstums aus wässrigen Lösungen zu erforschen und daraus eine optimierte Prozesskontrolle abzuleiten. Dabei werden zwei Verfahren des Nanodrahtwachstums näher betrachtet: Dies sind die dielektrophoretische Assemblierung von neutralen Molekülen oder Metallclustern sowie die gerichtete elektrochemische Nanodrahtabscheidung (engl. directed electrochemical nanowire assembly), bei der metallhaltige Ionen im elektrischen Wechselfeld an der Nanodrahtspitze zunächst reduziert und anschließend als Metallatome abgeschieden werden. Zur Beschreibung der Transport- und Wachstumsprozesse werden Kontinuumsmodelle eingesetzt. Darüber hinaus hat es sich als notwendig erwiesen, elektrokinetische Fluidströmungen zu berücksichtigen, um die experimentellen Beobachtungen zu reproduzieren. Die auftretenden partiellen Differenzialgleichungen werden mittels der Finiten Elemente Methode (FEM) numerisch gelöst. Die Auswirkungen der Prozessparameter auf das Nanodrahtwachstum werden durch den Vergleich von experimentellen Ergebnissen mit Parameterstudien analysiert. Die Auswertung hat ergeben, dass für das dielektrophoretische Wachstum ein durch Wechselfeldelektroosmose (engl. AC electro-osmosis) angetriebener Fluidstrom die Drahtwachstumsgeschwindigkeit und -morphologie maßgeblich beeinflusst. Im Falle der gerichteten elektrochemischen Nanodrahtabscheidung lässt sich die Drahtmorphologie über das angelegte elektrische Wechselsignal steuern. Unter Verwendung des Wachstumsmodells ist ein optimiertes Signal generiert worden, dessen Parametrisierung eine gezielte Anpassung auf den chemischen Ausgangsstoff und den gewünschten Drahtdurchmesser erlaubt.
Hesselbarth, Maximilian H. K. "Analysing and modelling spatial patterns to infer the influence of environmental heterogeneity using point pattern analysis, individual-based simulation modelling and landscape metrics." Doctoral thesis, 2020. http://hdl.handle.net/21.11130/00-1735-0000-0005-1391-1.
Full textKloß, Sebastian. "Simulation-Optimization of the Management of Sensor-Based Deficit Irrigation Systems." Doctoral thesis, 2014. https://tud.qucosa.de/id/qucosa%3A29047.
Full textTomlinson, Kyle Warwick. "Consequences of architecture and resource allocation for growth dynamics of bunchgrass clones." Thesis, 2005. http://hdl.handle.net/10413/1749.
Full textThesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.
Hill, Alexandra Verfasser], and Christian [Verfasser] [Lindner. "Modelling informal urban growth under rapid urbanisation : a CA-based land-use simulation model for the city of Dar es Salaam, Tanzania / by Alexandra Hill and Christian Lindner." 2010. http://d-nb.info/1006981721/34.
Full textvan, Embden Joel Leonard. "Synthesis and optical properties of CdSe core and core/shell nanocrystals." 2008. http://repository.unimelb.edu.au/10187/3225.
Full textMahmud, H. M. Iqbal. "Simulation of the suppression of fires using water mists." Thesis, 2016. https://vuir.vu.edu.au/31116/.
Full textSchwichtenberg, Guido. "Managementmodell für die Analyse von Waldbauszenarien in Nothofagus-Beständen." Doctoral thesis, 2007. http://hdl.handle.net/11858/00-1735-0000-0006-B109-E.
Full textThorpe, Hilary Claire. "Clearcut Solutions? An Evaluation of Partial Harvesting in the Black Spruce Boreal Forest." Thesis, 2008. http://hdl.handle.net/1807/17267.
Full textJardim, José Manuel Norberto. "The underground economy and the fiscal stance." Doctoral thesis, 2012. http://hdl.handle.net/10400.5/13548.
Full textThe inevitability of taxes and regulations, that cause agents to go underground, forces the authorities to tolerate some underground economic activity and grants the underground economy natural features. The natural level of the underground economy is defined as the level of underground economic activity in the decentralized equilibrium, provided that the actual structural characteristics of the economy and social preferences are accounted for by imbedding them in the Walrasian system of general equilibrium equations. Its existence is proven using two variants of neoclassical general equilibrium models. The underground economy is found to influence the successfulness of fiscal consolidation programmes, depending on the position of the economy relative to critical fiscal thresholds associated with the natural level of the underground economy. Tax increases yield higher tax proceeds up to the threshold, and lower tax proceeds, passed the threshold, due to a stronger expansion of the natural level of the underground economy. Tax proceeds reach their maximum at the threshold. Tax based programmes are found ineffective in high tax developed economies, operating passed the threshold. In contrast, its successfulness in the developing world, where most economies operate below the threshold with low taxes, is not influenced by the underground economy.
Perante a inevitabilidade de impostos e regulamentação, que estão na origem da economia subterranea, as autoridades vêem-se forçadas a tolerar actividades económicas subterraneas. Isto confere urn carácter natural à economia subterrânea. A existência de uma taxa natural de economia subterranea e provado utilizando dois modelos neoclassicos de equilibrio gereal. A taxa natural de economia subterranea define-se como o nivel de actividade económica subterranea no equilibrio descentralizado, dadas as propriedades estruturais da economia e das preferências sociais, que se incluem no sistema Walrasiano de equações de equilibrio geral. Prova-se que a economia subterranea influencia o resultado de programas de consolidação orçamental. Isto depende da localização da economia face a valores fiscais criticos associados a taxa natural de economia subterranea. A seguir a urn aumento de impostos, as receitas começam por crescer, atingindo o máximo no ponto critico, para a segmr GUt, devido a uma expansão da taxa natural de economia subterrânea. Programas assentes no aumento de impostos não são bern sucedidos em paises desenvolvidos com cargas fiscais elevadas, que operam alem do ponto critico. Já os paises em desenvolvimento, cuja maioria opera abaixo do ponto critico com cargas fiscais baixas, a economia subterranea não parece influenciar a eficácia dos programas.
N/A
(5930906), Jacob J. Torres. "The Biowall Field Test Analysis and Optimization." Thesis, 2019.
Find full textA residential botanical
air filtration system (Biowall) to investigate the potential for using
phytoremediation to remove contaminants from indoor air was developed. A full scale and functioning prototype was
installed in a residence located in West Lafayette, Indiana. The prototype was integrated into the central
Heating, Ventilating, and Air Conditioning (HVAC) system of the home. This
research evaluated the Biowall operation to further its potential as an energy
efficient and sustainable residential air filtration system.
The main research effort began after the Biowall was installed in the residence. A field evaluation, which involved a series of measurements and data analysis, was conducted to identify treatments to improve Biowall performance. The study was conducted for approximately one year (Spring 2017-Spring 2018). Based on the initial data set, prioritization of systems in need of improvement was identified and changes were imposed. Following a post-treatment testing period, a comparison between the initial and final performances was completed with conclusions based on this comparison.
The engineering and analysis reported in this document focus on the air flow path through the Biowall, plant growth, and the irrigation system. The conclusions provide an extensive evaluation of the design, operation, and function of the Biowall subsystems under review.