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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Using traditional modelling approaches for a MBR system to investigate alternate approaches based on system identification procedures for improved design and control of a wastewater treatment process

Paul, Parneet January 2011 (has links)
The specific research work described in this thesis forms part of a much larger research project that was funded by the Technology Programme of the UK Government. This larger project considered improving the design and efficiency of membrane bioreactor (MBR) plant by using modelling, simulation and laboratory methods. This research work uses phenomenological mechanistic models based on MBR filtration and biochemical processes to measure the effectiveness of alternative behavioural models based upon input-output system identification methods. Both model types are calibrated and validated using similar plant layouts and data sets derived for this purpose. Results prove that although both approaches have their advantages, they also have specific disadvantages as well. In conclusion, the MBR plant designer and/or operator who wishes to use good quality, calibrated models to gain a better understanding of their process, should carefully consider which model type is selected based upon on what their initial modelling objectives are (e.g. using either a physically mechanistic model or an input-output behaviourial model). Each situation usually proves unique. In this regard, this research work creates a "Model Conceptualisation Procedure" for a typical MBR which can be used by future researchers as a theoretical framework which underpins any newly created model type. There has been insufficient work completed to date on using a times series input-output approach in the model development of a wastewater treatment plant, so only general conclusions can be made from this research work. However, it can be stated that this novel approach seems to be applicable for a membrane filtration model if care it taken to select appropriate input-output model structures, such as those suggested in the "Model Conceptualisation Procedure". In the case of the development of a MBR biological model, it is thought that a conventional Activated Sludge model produced by the IWA could be coupled to a input-output model structure as suggested by this report to give a hybrid model structure that may have the advantages of both model types. Further research work is needed in this area. Future work that should follow on from this research study should focus on whether these input-output models could be used for predictive control purposes, whether an integrated model could be created, and whether a benchmark could be created for the three main MBR configurations.
2

Super-Helices for Hair Modeling and Dynamics

Bergbom, Mattias January 2007 (has links)
<p>We present core components of a hair modeling and dynamics solution for the feature film industry. Recent research results in hair simulation are exploited as a dynamics model based on solving the Euler-Lagrange equations of motion for a discretized Cosserat curve is implemented in its entirety. Solutions to the dynamics equations are derived and a framework for symbolic integration is outlined. The resulting system is not unconditionally positive definite but requires balanced physical parameters in order to be solvable using a regular linear solver. Several implementation examples are presented, as well as a novel modeling technique based on non-linear optimization.</p>
3

Super-Helices for Hair Modeling and Dynamics

Bergbom, Mattias January 2007 (has links)
We present core components of a hair modeling and dynamics solution for the feature film industry. Recent research results in hair simulation are exploited as a dynamics model based on solving the Euler-Lagrange equations of motion for a discretized Cosserat curve is implemented in its entirety. Solutions to the dynamics equations are derived and a framework for symbolic integration is outlined. The resulting system is not unconditionally positive definite but requires balanced physical parameters in order to be solvable using a regular linear solver. Several implementation examples are presented, as well as a novel modeling technique based on non-linear optimization.
4

Design, Modeling and Simulation of Planar Waveguide Optical Splitter

Huang, Min 07 1900 (has links)
<p> 1-by-N optical power splitters are primary components in the field of integrated optics and optical transmission systems. Planar waveguide optical power splitters are key devices to realize low-cost optical transmission systems through photonic integration. The goal of this thesis is to design, model and simulate a novel planar waveguide optical power splitter for optical transmission systems and Fiber to the Home (FTTH) networks.</p> <p> The first chapter is an introduction. This chapter gives the background of power splitter, reviews the existing devices and explains why our novel design is needed.</p> <p> The idea of this novel power splitter is presented in Chapter 2, including analytical formulations, theoretical calculations and designs. This serves as a theoretical foundation for the development and verification of different parts presented in Chapter 3. The novel power splitter design is composed of a series of waveguide lenses and waveguide phase shifts. The analytical formulations are derived and intensive numerical simulations are performed to verify and investigate this new power splitter. Also the conventional Beam Propagation Method (BPM) is studied in this chapter, which provides a numerical preparation for the device simulation and design in the subsequent chapter.</p> <p> The design results are shown in Chapter 4. The novel power splitter design predicts good performance with more compact device size, better output and smaller wavelength dependence. This chapter demonstrated the possibility of new power splitter working as a better approach to the existing MMI or other structures.</p> <p> Finally, Chapter 5 gives a conclusion to this thesis. The limitations of this work are presented and the future works are proposed.</p> / Thesis / Master of Applied Science (MASc)
5

MODELING AND SIMULATION OF SINGLE SPOOL JET ENGINE

KAMARAJ, JAYACHANDRAN 31 March 2004 (has links)
No description available.
6

Finite Element Modelling And Simulation Of Drying Isotropic And Anisotropic Food Samples

Soydan Karabacak, Meltem 01 February 2013 (has links) (PDF)
The aim of this study was to investigate drying characteristics (temperature gradient, rate of drying and temperature change, drying time, diffusivity values, shrinkage) of isotropic and anisotropic foods by observing the changes in temperatures at four different locations and moisture contents and to build an appropriate model for simulation of temperature and moisture distribution using finite element method. The lean meat samples (anisotropic) with three fiber configurations (v / flow normal to fiber, drying along the fiber, h1 / flow normal to fiber, h2 / flow along to fiber) and minced meat (isotropic) were dried at two different temperatures (48
7

Analytic and agent-based approaches: mitigating grain handling risks

2013 March 1900 (has links)
Agriculture is undergoing extreme change. The introduction of new generation agricultural products has generated an increased need for efficient and accurate product segregation across a number of Canadian agricultural sectors. In particular, monitoring, controlling and preventing commingling of various wheat grades is critical to continued agri-food safety and quality assurance in the Canadian grain handling system. The Canadian grain handling industry is a vast regional supply chain with many participants. Grading of grain for blending had historically been accomplished by the method of Kernel Visual Distinguishability (KVD). KVD allowed a trained grain grader to distinguish the class of a registered variety of wheat solely by visual inspection. While KVD enabled rapid, dependable, and low-cost segregation of wheat into functionally different classes or quality types, it also put constraints on the development of novel traits in wheat. To facilitate the introduction of new classes of wheat to enable additional export sales in new markets, the federal government announced that KVD was to be eliminated from all primary classes of wheat as of August 1, 2008. As an alternative, the Canadian Grain Commission has implemented a system called Variety Eligibility Declaration (VED) to replace KVD. As a system based on self-declaration, the VED system may create moral hazard for misrepresentation. This system is problematic in that incentives exist for farmers to misrepresent their grain. Similarly, primary elevators have an incentive to commingle wheat classes in a profitable manner. Clearly, the VED system will only work as desired for the grain industry when supported by a credible monitoring system. That is, to ensure the security of the wheat supply chain, sampling and testing at some specific critical points along the supply chain is needed. While the current technology allows the identification of visually indistinguishable grain varieties with enough precision for most modern segregation requirements, this technology is relatively slow and expensive. With the potential costs of monitoring VED through the current wheat supply chain, there is a fundamental tradeoff confronting grain handlers, and effective handling strategies will be needed to maintain historical wheat uniformity and consistency while keeping monitoring costs down. There are important operational issues to efficiently testing grain within the supply chain, including the choice of the optimal location to test and how intensively to test. The testing protocols for grain deliveries as well as maintaining effective responsiveness to information feedback among farmers will certainly become a strategic emphasis for wheat handlers in the future. In light of this, my research attempts to identify the risks, incentives and costs associated with a functional declaration system. This research tests a series of incentives designed to generate truthful behavior within the new policy environment. In this manner, I examine potential and easy to implement testing strategies designed to maintain integrity and efficiency in this agricultural supply chain. This study is developed in the first instance by using an analytic model to explore the economic incentives for motivating farmer’s risk control efforts and handlers’ optimal handling strategies with respect to testing cost, penalty level, contamination risks and risk control efforts. We solve for optimal behavior in the supply chain assuming cost minimization among the participants, under several simplifying assumptions. In reality, the Canadian grain supply chain is composed of heterogeneous, boundedly rational and dynamically interacting individuals, and none of these characteristics fit the standard optimization framework used to solve these problems. Given this complex agent behavior, the grain supply chain is characterized by a set of non-linear relationships between individual participants, coupled with out of equilibrium dynamics, meaning that analytic solutions will not always identify or validate the set of optimized strategies that would evolve in the real world. To account for this inherent complexity, I develop an agent-based (farmers and elevators) model to simulate behaviour in a more realistic but virtual grain supply chain. After characterizing the basic analytics of the problem, the grain supply chain participants are represented as autonomous economic agents with a certain level of programmed behavioral heterogeneity. The agents interact via a set of heuristics governing their actions and decisions. The operation of a major portion of the Canadian grain handling system is simulated in this manner, moving from the individual farm up through to the country elevator level. My simulation results suggest testing strategies to alleviate misrepresentation (moral hazard) in this supply chain are more efficient for society when they are flexible and can be easily adjusted to react to situational change within the supply chain. While the idea of using software agents for modeling and understanding the dynamics of the supply chain under consideration is somewhat novel, I consider this exercise a first step to a broader modeling representation of modern agricultural supply chains. The agent-based simulation methodology developed in my dissertation can be extended to other economic systems or chains in order to examine risk management and control costs. These include food safety and quality assurance network systems as well as natural-resource management systems. Furthermore, to my knowledge there are no existing studies that develop and compare both analytic and agent-based simulation approaches for this type of complex economic situation. In the dissertation, I conduct explicit comparisons between the analytic and agent-based simulation solutions where applicable. While the two approaches generated somewhat different solutions, in many respects they led to similar overall conclusions regarding this particular agricultural policy issue.
8

Modeling And Motion Simulation Of An Underwater Vehicle

Kucuk, Koray 01 September 2007 (has links) (PDF)
This thesis involves modeling, controller design, and test case simulations for an underwater vehicle. Firstly, a complete dynamic model of the vehicle is developed with six degrees of freedom. The model includes the nonlinearities associated with the hydrodynamic forces and moments. The thrusters of the vehicle are also modeled. Then, using appropriate linearizations of the model, position and rate controllers are designed for the forward, downward, and turning motions of the vehicle. Finally, the designed controllers are tested for various maneuvers by means of simulations using the nonlinear dynamic model of the vehicle. The simulation results show that the designed controllers are quite satisfactory for the intended maneuvers.
9

Numerical Modeling And Performance Analysis Of Solar-powered Ideal Adsorption Cooling Systems

Taylan, Onur 01 May 2010 (has links) (PDF)
Energy consumption is continuously increasing around the world and this situation yields research to find sustainable energy solutions. Demand for cooling is one of the reasons of increasing energy demand. This research is focused on one of the sustainable ways to decrease energy demand for cooling which is the solar-powered adsorption cooling system. In this study, general theoretical performance trends of a solar-powered adsorption cooling system are investigated using TRNSYS and MATLAB. Effects of different cycle enhancements, working pairs, operating and design conditions on the performance are analyzed through a series of steady and seasonal-transient simulations. Additionally, a normalized model is presented to investigate the effects of size of the system, need for backup power, collector area and mass of adsorbent. Results are presented in terms of values and ratios of cooling capacity weighted COP. For the conditions explored, the thermal wave cycle, wet cooling towers, high evaporation temperatures and evacuated tube collectors produced the highest COP values. Moreover, the heat capacity of the adsorbent bed and its shell should be low for the simple and heat recovery cycles and the adsorbent bed should be cooled down to the condensation temperature for all cases to achieve the highest possible COP. The selection of working pair should depend on the temperature of the available heat source (solar energy in this study) since each working pair has a distinct operating temperature range. Furthermore, there is always a need for backup power for the analyzed location and the system.
10

Ambiente de simulação de manipuladores paralelos : modelagem, simulação e controle de uma plataforma Stewart / Simulation environmental for parallel manipulator : modeling simulation and control of Stewart platform

Lara Molina, Fabian Andres 09 February 2008 (has links)
Orientador: João Mauricio Rosario / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-12T18:15:19Z (GMT). No. of bitstreams: 1 LaraMolina_FabianAndres_M.pdf: 3777126 bytes, checksum: 5d2bb864ea5a4dc9fb76ddeeeb83c38f (MD5) Previous issue date: 2008 / Resumo: O presente trabalho recopila e aplica conceitos concernentes à modelagem dos manipuladores paralelos, desta maneira é proposta um ambiente de simulação para manipuladores paralelos aplicada à Plataforma Stewart. O manipulador paralelo de seis graus de liberdade - Plataforma Stewart é utilizado em aplicações que requerem alto desempenho de posicionamento: alta rigidez, alta razão capacidade de carga - peso do manipular, alta exatidão no movimento. Entre as aplicações nas quais se tem utilizado a Plataforma Stewart estão: simuladores de vôo, manipuladores cirúrgicos, máquinas ferramentas CNC, sistemas de locomoção bípedes, etc. São enfatizados aspectos concernentes à modelagem cinemática e dinâmica deste manipulador. A partir do modelo é proposta a simulação e controle de posição no espaço das juntas em MATLAB - SimulinkTM. A validação da simulação é feita mediante um estudo de casos / Abstract: The present work involves and applies parallel manipulator design concepts; therefore it is proposed a parallel manipulator design methodology applied to Stewart Platform. In this research project, it is modeled, simulated and analyzed the six degrees of freedom parallel manipulator - Stewart Platform. This system is used on applications with high position performance: high stiffness, high useful load - manipulator weigh and high accuracy. The Stewart Platform has been applied in: flight simulators, surgery manipulators, CNC machines, biped locomotion systems, etc. In this work are emphasized on Stewart Platform cinematic and dynamic modeling concepts. Based on manipulator model is proposed the simulation and joint space position control in MATLAB - SimulinkTM. The simulation is validated thought a case study / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

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