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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.
61

Development of a Dynamic Simulation Model for Equalization Tanks

Fotso, Simo Eugene 06 August 2021 (has links)
The influent to a water and resource recovery facility (WRRF) generally exhibits significant diurnal variations in flow rate and load concentration. This makes determining the operating parameters and subsequently the overall operation of plants difficult, especially in developing countries due to the lack of highly skilled operators. Hence, there is an incentive for the control and operation of WRRFs in developing countries to be improved. Flow equalization tanks were identified as a potential method to attenuate the diurnal variations in flow rate and load concentration into plants. The main aim of this research was to develop a viable dynamic simulation model for the operation of flow equalization tanks, within a plant-wide framework (to allow for the evaluation of design and control strategies). The next aim was to determine the benefits of equalization tanks towards design and optimised operation of future WRRFs via scenario analyses. Finally, the effects of the equalization tank on the performance of various unit processes in a WRRF were to be investigated. The model was developed in three steps; i) the development of the required equations to model equalization tanks, ii) mass balance throughout the model for internal consistency and iii) scenario analyses to determine if the model generated reasonable and scientifically sound outputs. The model was developed using Microsoft Excel Visual Basic (VBA) and WEST®. Two scenarios were considered to assess the equalization tank modelled. Scenario One involved the comparison of the capital cost, unit process sizes and total footprint of a balanced sludge age Modified Ludzack-Ettinger (MLE) system with and without an equalization tank. Scenario Two compared the plant performance of the MLE system designed in Scenario One with and without a flow equalization tank. A dynamic simulation model replicating equalization tanks was successfully developed. From scenario analyses, it was determined that using an MLE system and only considering equalization of flow, there was a reduction in the size of several unit processes by 8-9% (primary settling tank, biological reactors, secondary settling tank, flotation unit, anoxic-aerobic digester), due to the less conservative design values that could be used as the variations of the influent were decreased. Despite this, a 13% overall increase in the footprint of the WRRF was observed due to the addition of the equalization tank. The attenuation of diurnal flow variations also resulted in reduction of various plant parameters by up to 50% (flow, OUR, VSS flux). Finally, there was a 10% improvement in the performance of various unit processes due to the presence of the equalization tank. In conclusion, the inclusion of equalization tanks in WRRFs has significant positive effects. These results were obtained with equalization of flow only. Some other limitations were experienced during the project resulting in the following recommendations: further research will be needed to validate and calibrate the model, As the model was not successfully incorporated in a plant-wide framework, further developments in that direction are required, as well as including the equalization of load in the model.
62

Bezpečnostní parkovací brzdy pro servomotory / Safe brakes for servomotors

Štencl, Michal January 2017 (has links)
This Master thesis is focused on electromagnetic brakes for servomotors. In the first chapter is described principle of operation, later then design and main parameters are explained. The main part of thesis is focused on calculation of dynamic parameters of electromagnetic brakes. Calculations are solved first by analytic method in Matlab–Simulink, then by finite element analysis. Results are compared with measurements on prototype brake.
63

Signální dráha produkce butanolu bakterií rodu Clostridium / Signaling Pathway for Butanol Production in Solventogenic Clostridium Bacteria

Musilová, Jana January 2019 (has links)
Diplomová práce se zabývá studiem signální dráhy produkce butanolu bakterií rodu Clostridium. V první části pojednává o modelování signálních drah pomocí metod systémové biologie. Navazuje popisem zisku dat pro tvorbu a úpravu modelů signálních drah s hlavním zaměřením na techniky pro zjištění genové exprese, produkce a fenotypu. Třetí sekcí je získání základního modelu signální dráhy zapojené do produkce butanolu u solventogenních klostridií. Posledním bodem a zároveň hlavním cílem je vytvoření dynamického modelu signální dráhy produkce butanolu kmene Clostridium beijerinckii NRRL B-598, jeho vyhodnocení pomocí statické a dynamické analýzy a srovnání s biologickými daty.
64

Regulation of Task Partitioning by a "Common Stomach": A Model of Nest Construction in Social Wasps

Karsai, I., Schmickl, T. 01 July 2011 (has links)
Metapolybia wasps construct their nests on flat surfaces using plant materials, which they process into paper. For processing the pulp wasps need water, which is collected by water foragers, and it is transferred to pulp foragers indirectly via a "common stomach." The common stomach is formed by generalist wasps that can engage in water exchange and can store water in their crops. Our goal is to provide an alternative model for regulating task partitioning in construction behavior, focusing on worker connectivity instead of using threshold curves to model mechanisms of colony-level regulation. We propose that the existence of an information center and of a network of worker interactions, which establish sets of positive and negative feedbacks, allow collective regulation of colony-wide behaviors. Using a Stock and Flow modeling framework, we illustrate that the common stomach could serve both as a temporal storage for water and also as a source of information about the colony's current demands related to nest construction tasks. Our model predicts that assessing colony needs via individual interactions with the common stomach leads to a robust regulation of task partitioning in construction behavior. Using perturbation experiments in our simulations, we show that this emergent task allocation is able to dynamically adapt to perturbations of the environment and to changes in colony-level demands or population structure. Our model closely mimics and predicts the behavior of Metapolybia wasps, demonstrating that the regulation mechanism based on worker connectivity through a common stomach is a plausible hypothesis for the organization of collective behavior.
65

Strategické řízení elektronického obchodu / Strategic Management of E-business

Luhan, Jan January 2012 (has links)
The dissertation deals with designing of model for support of strategic management of e-business which is characteristic by integrating existing management processes in the company. The basic mathematical model uses the solution of differential equations and is adaptable for the needs of particular entity.
66

System Identification and Model-Based Control of Quadcopter UAVs

Szabo, Andrew P. 10 May 2019 (has links)
No description available.
67

Development of a Dynamic Simulation Model for Equalization Tanks

Simo, Eugene Fotso 14 February 2022 (has links)
The influent to a water and resource recovery facility (WRRF) generally exhibits significant diurnal variations in flow rate and load concentration. This makes determining the operating parameters and subsequently the overall operation of plants difficult, especially in developing countries due to the lack of highly skilled operators. Hence, there is an incentive for the control and operation of WRRFs in developing countries to be improved. Flow equalization tanks were identified as a potential method to attenuate the diurnal variations in flow rate and load concentration into plants. The main aim of this research was to develop a viable dynamic simulation model for the operation of flow equalization tanks, within a plant-wide framework (to allow for the evaluation of design and control strategies). The next aim was to determine the benefits of equalization tanks towards design and optimised operation of future WRRFs via scenario analyses. Finally, the effects of the equalization tank on the performance of various unit processes in a WRRF were to be investigated. The model was developed in three steps; i) the development of the required equations to model equalization tanks, ii) mass balance throughout the model for internal consistency and iii) scenario analyses to determine if the model generated reasonable and scientifically sound outputs. The model was developed using Microsoft Excel Visual Basic (VBA) and WEST®. Two scenarios were considered to assess the equalization tank modelled. Scenario One involved the comparison of the capital cost, unit process sizes and total footprint of a balanced sludge age Modified Ludzack-Ettinger (MLE) system with and without an equalization tank. Scenario Two compared the plant performance of the MLE system designed in Scenario One with and without a flow equalization tank. A dynamic simulation model replicating equalization tanks was successfully developed. From scenario analyses, it was determined that using an MLE system and only considering equalization of flow, there was a reduction in the size of several unit processes by 8-9% (primary settling tank, biological reactors, secondary settling tank, flotation unit, anoxic-aerobic digester), due to the less conservative design values that could be used as the variations of the influent were decreased. Despite this, a 13% overall increase in the footprint of the WRRF was observed due to the addition of the equalization tank. The attenuation of diurnal flow variations also resulted in reduction of various plant parameters by up to 50% (flow, OUR, VSS flux). Finally, there was a 10% improvement in the performance of various unit processes due to the presence of the equalization tank. In conclusion, the inclusion of equalization tanks in WRRFs has significant positive effects. These results were obtained with equalization of flow only. Some other limitations were experienced during the project resulting in the following recommendations: further research will be needed to validate and calibrate the model, As the model was not successfully incorporated in a plant-wide framework, further developments in that direction are required, as well as including the equalization of load in the model.
68

Modeling and Simulation of a Multi-Unit Tracked Vehicle

Kanarat, Amnart 13 November 1999 (has links)
A multi-unit tracked vehicle such as a continuous haulage system is widely used in underground mining applications due to its high mobility and payload capacity on rugged and soft terrain. To automate such a system, a high fidelity model of a tracked vehicle is essential in designing a controller for each tracked vehicle in the system, and a system model is required to simulate its response to input commands. This thesis presents the 2-D mathematical models of a tracked vehicle and a multi-unit tracked vehicle. All existing track-terrain interaction models are investigated and modified. By employing the modified track-terrain interaction model and applying Newton's second law of motion, the equations of motion of both single and multi-unit tracked vehicles can be derived. Computer programs for simulating the motions of these tracked vehicles on level ground have been implemented on a digital computer based on the derived system of differential equations. The fourth-order Runge-Kutta and Keun's methods are adopted to numerically integrate these differential equations. The simulation results clearly show that the programs can accurately predict the motion of a tracked vehicle maneuvered on horizontal plane, and closely predict the response of a multi-unit tracked vehicle operated on level ground its command inputs. / Master of Science
69

Modeling frameworks to evaluate energy autarky of wastewater treatment systems

Sarpong, Gideon 01 May 2020 (has links)
This research demonstrates the use of two novel methodologies to evaluate energy autarky status of wastewater treatment plants (WWTPs) in two steps. Step I (analysis 1 and 2) focuses on overall energy performance evaluation of a conventional activated sludge process (CAS) using a quantitative mass balance model. Step II involves development of a dynamic model that simulates a future wastewater resource recovery facility (WRRF). The step I (analysis 1) focused on small WWTPs with treatment capacities less than 5 MGD. The results revealed that a CAS process can achieve energy autarky or energy-positive status when old technology equipment is replaced with new, high efficiency equipment to save 10-12% energy; aeration energy is reduced by installing nitritation/anammox nitrogen removal process; and energy production is enhanced with the addition of FOG for co-digestion. Analysis 2 of step I focusing on large plant capacities (i.e., > 20 MGD) evaluated the effect of influent wastewater strength (IWWS), primary treatment COD removal efficiency (PT-COD), and proper design of combined heat and power (CHP) systems on the overall energy performance. The results showed that energy autarky is feasible when PT-COD is 60% for low IWWS, 40% or greater for medium IWWS, and 30% or greater for high IWWS. In step II analysis, a new and dynamic model was developed by integrating high rate algal pond (HRAP) and anaerobic digester (AD) systems. The model was calibrated using the experimental data from recent studies. The results showed that this system can achieve energy autarky when advanced solids separation and co-digestion systems are included. Solids separation efficiency was increased from 75 to 90% to reduce the winter effluent COD concentrations from HRAP (by 20%). Similarly, nitrogen effluent concentrations were reduced by increasing the solids retention time. Future studies should focus on techno-economic and environmental life cycle impact analysis of these novel process configurations.
70

Control of Quadcopter UAV by Nonlinear Feedback

Ye, Haoquan 04 June 2018 (has links)
No description available.

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