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Lundh, Magnus. "Optimization and tuning of heat control". Thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-97936.
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Heat pumps have become even more popular when it’s about getting hot water and heat in our departments and villas. Before the heat pumps can be put into operation they have to go through some tests. IVT Industries AB performs the tests in different test rigs depending on the size or effect of the pump. The rig is divided in villapumps and real estate facilitypumps. Testrig F2 is one of the rigs where tests are performed on heatpumps in real estate facility’s. Doing adjustments of hot and cold water today, the IVT company uses cascades PIDcontrollers where the parameters has to be adjust on each tests. Optimization on the controllers have to adjust for the process time to become as short as possible but still there is a time demanded course of event because of the poor stabilitets in the controll and difficult adjustments of the parameters. With help of PID-controllers feedforward we achived. •Greater stabilitets •Faster process •Little adjustments •Lower energy consumption •Disturbance free regulationVärmepumpar har blivit allt mer populära när det gäller att få ut varmvatten och värme i våra fastigheter och villor. Innan värmepumparna skickas ut för drift måste de genomgå en del tester. Hos IVT utförs testerna i olika testriggar beroende på storleken eller effekten på pumpen. Riggen delas upp i Villapumpar och Fastighetspumpar. På IVT finnes Testrigg F2, en av riggarna där man utför tester på Fastighetsvärmepumparna. Vid in justering av varm och kallvatten använder sig IVT koncernen idag utav kaskadkopplade PID regulatorer när man utför tester där parametrarna för regulatorerna måste finjusteras vid varje installation. Regulatorerna optimeras för att få så kort process tid som möjligt men fortfarande är detta ett tidskrävande förlopp pga. Ostabilitet i regleringen och svårtrimmade regulatorer. Med hjälp av PID-framkoppling har vi uppnått. • Stabilare reglering •Snabbare processtid •Små justeringar av regulatorn •Lägre energiförbrukning •Störningsfri reglering
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Nordlöf, Anon y John Lundqvist. "Turbo Heat Transfer Modeling for Control". Thesis, Linköpings universitet, Fordonssystem, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-150352.
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The demand for lower emission engines forces the car industry to build moreefficient engines. Turbocharged engines are on the rise, and better understandingof the heat transfer and efficiency of the turbocharger is needed to build better ones. A lot is known about the overall efficiency of the turbocharger, but not much is known about where the heat losses are located and how they interact with each other. This thesis presents a one dimensional model for heat exchange in the tur-bocharger and investigates how the heat flows from the hot exhaust gases to the cold intake air. Data is gathered by performing tests on a single scroll turbocharger in an engine test bench at Linköping University. The tests are focused on operating points where the air mass flow is low and neither the compressor nor the turbine works adiabatically. The results show that it is possible to estimate the heat flows together withthe efficiency of the turbine and compressor using only known parameters, elim-inating the need to add any new sensors to the engine.
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Storm, Josefin. "Heat Transfer Modeling for Turbocharger Control". Thesis, Linköpings universitet, Fordonssystem, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-141949.
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Turbocharging is a way to stay competitive on the market where there are increasing demands on fuel consumption and engine performance. Turbocharging lets the engine work closer to its maximum power and thereby reduces the relative losses due to pumping and friction. The turbocharger is exposed to big temperaturedifferences and heat flows will occur both internally between the turbine and the compressor as well as between the turbocharger and its surroundings. Away to get a better understanding of the behaviour of the turbocharger is to understand the heat flows better. This thesis is therefore aimed at investigating theeffect of heat transfer on the turbocharger. In the thesis, different ways of accountfor the heat transfer within the turbocharger is investigated and a heat transfermodel is presented and validated. The model can be used as a tool to estimate theimportance of different heat flows within the turbocharger. A set of heat transfer coefficients are estimated and the heat transfer is modelled with good accuracyfor high engine loads and speeds.
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Akkam, Mazen. "Microcomputer based heat controller". Thesis, Kansas State University, 1985. http://hdl.handle.net/2097/9816.
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Mulford, Rydge Blue. "Dynamic Radiation Heat Transfer Control Through Geometric Manipulation". BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/8134.
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The surface area and radiative properties of an object influence the rate of radiative emission from the object's surface and the rate of radiative absorption into the surface. Control of these variables would allow for the radiative heat transfer behavior of the surface to be manipulated in real time. Origami tessellations, being a repeated pattern of linked, dynamic surfaces, provide a framework by which dynamic control of apparent radiative properties and surface area is possible. The panels within a tessellation form cavities whose aspect ratio varies as the device actuates. The cavity effect suggests that the apparent radiative properties of the cavity openings will vary as a function of aspect ratio. The apparent absorptivity of an accordion tessellation formed from folded shim stock is shown experimentally to increase by 10x as the tessellation actuates from fully extended to within 10\% of a completely-folded state. Analytical models and Monte Carlo ray tracing are used to quantify the apparent radiative properties of an infinite V-groove for a variety of conditions, including specular or diffuse reflection and diffuse or collimated incident irradiation. For a diffuse V-groove, apparent radiative properties increase with increasing V-groove aspect ratio but do not approach unity. Highly reflective surfaces exhibit the largest relative increase in apparent radiative properties with actuation. Closed-form correlations achieve an average relative error of 2.0\% or less. For a specular V-groove, apparent radiative properties approach unity as the V-groove collapses towards an infinite aspect ratio. The apparent absorptivity for a V-groove exposed to collimated irradiation shows significant variations over small actuation distances, increasing by 5x over a small actuation range. For certain conditions the apparent absorptivity of a V-groove subject to collimated irradiation decreases as the aspect ratio increases.For an isothermal accordion tessellation the net radiative heat exchange continuously decreases as the surface is collapsed for most conditions, indicating that the reduction in apparent surface area generally dominates the increase in apparent radiative properties. Net radiative heat transfer values decrease by 7x for collimated irradiation and specular reflection over small actuation distances. Specular V-grooves subject to collimated irradiation occasionally show an increase in net radiative heat transfer as the device collapses. A non-isothermal dynamic radiative fin achieves a 3x reduction in heat transfer as the fin collapses; this value can be increased with the use of highly conductive materials and by increasing the length of the fin. The fin efficiency of a collapsible fin increases as the fin collapses. An experimental prototype of a collapsible fin is developed and tested in a vacuum environment, achieving a 1.32x reduction in heat transfer for a limited actuation range, where a numerical model suggests this prototype may achieve a 2.23x reduction in heat transfer over the full actuation range.
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Vizcaino-Garcia, Fidel. "Control strategies for flexible heat exchanger networks". Thesis, University of Manchester, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.503089.
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Sedaghat, Ahmadreza. "Cement Heat of Hydration and Thermal Control". Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6142.
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Heat of hydration is a property of Portland cement and a direct result of the chemical reaction between cement and water. The amount of heat released is dependent upon the cement mineralogical composition, curing temperature, water to cement ratio, and cement fineness. High temperature resulting from heat of hydration (thereon referred to as HOH) of cement can affect the hydration process, and consequently the kinetics of development of the mechanical properties of concrete. One of the main reasons triggering the interest in HOH of cement is its implication in thermal cracking of concrete. The high temperature gradient between the inner core and the outer surface of a concrete element is known to result in large tensile stresses that may exceed tensile strength, thus leading to early–age thermal cracking in mass concrete.
This dissertation initially addresses accurately predicting the heat of HOH of Portland cement at seven days based on the heat flow data collected from isothermal calorimetry for a time interval of 0-84 h. This approach drastically reduces the time required to identify the seven day HOH of Portland cement.
The second part of this study focuses on cement fineness and its critical role on the heat generated by Portland cement during hydration. Using a matrix of four commercially available Portland cements, representing a wide range of mineralogical composition, and subjecting each of the as-received cements to several grinding increments, a linear relationship was established between cement fineness and heat of hydration. The effect of cement fineness and mineralogical composition on HOH of Portland cement was then related through a mathematical expression to predict the HOH of Portland cement based on its mineralogical composition and fineness. Three expressions were proposed for the 1, 3 and 7 day HOH. The findings indicate that the equations developed, based on cement main phase composition and fineness, can be used to identify cements with high heat of HOH that may cause thermal cracking in mass concrete elements. Also, the equations can be used to correlate the HOH with the other properties of Portland cement for quality control and prediction of chemical and physical properties of manufactured Portland cement and concrete.
Restrained shrinkage experiments results on mortar specimens prepared with cements of variable phase composition and fineness indicate that interaction of C3A and sulfate source is the prime phenomenon followed by cement fineness as the second main factor influencing concrete cracking. In order to minimize this effect, the third part of this study focused on studying alternatives that can lower the heat generated by concrete on hydration through the incorporation of nanomaterials; namely, graphene nanoparticles. The results indicate that incorporation of graphene a as replacement for Portland cement improves thermal diffusivity and electrical conductivity of the cement paste. Consequently, the use of graphene can trigger improvement of the thermal conductivity of concrete elements thus reducing the cracking potential of concrete.
Measurements of HOH of graphene-cement paste, at w/c=0.5, using isothermal conduction calorimetry, indicate that incorporation of graphene up to 10% increases the length of the induction period while reduces the magnitude of the alite main hydration peak due to the filler effect. Furthermore, increasing the w/c ratio from 0.5 to 0.6 and graphene content from 1 % to 10% (as a partial replacement of cement) increases the 7 day HOH of Portland cement by 50 J/g. Isothermal conduction calorimetry heat flow curves show that incorporation of graphene particles up to 10% does not have significant effect on interaction of aluminates and sulfates sources since the time of occurrence of the C3A sulfate depletion peak is not affected by graphene substitution up to 10%.
Full factorial statistical design and analysis conducted on compressive strength data of mortar specimens prepared at two w/c ratios, using cements of different finenesses and graphene content indicates that the quantity of graphene and the physical interaction due to variable w/c, graphene and cement fineness, have the smallest P-value among all the samples, representing the most significant impact on compressive strength of mortar samples. It appears that in graphene cement paste composites, addition of 1% graphene results in 21% reduction of Young’s modulus. Increasing the graphene content from 1% to 5% and/or 10% does not show significant effect on Young’s modulus. Similar trends can be observed in the hardness of graphene cement paste samples.
In conclusion, partial replacement of Portland cement with graphene nanoparticles in concrete mixtures is a good alternative to lower the cracking potential in mass concrete elements.
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Lartz, Douglas John. "Feedforward temperature control using a heat flux microsensor". Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-06302009-040309/.
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Sundbrandt, Markus. "Control of a Ground Source Heat Pump using Hybrid Model Predictive Control". Thesis, Linköpings universitet, Reglerteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-71369.
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The thesis has been conducted at Bosch Thermoteknik AB and its aim is to develop a Model Predictive Control (MPC) controller for a ground source heat pump which minimizes the power consumption while being able to keep the inside air temperature and Domestic Hot Water (DHW) temperature within certain comfortintervals. First a model of the system is derived, since the system consists of both continuous and binary states a hybrid model is used. The MPC controller utilizes the model to predict the future states of the system, and by formulating an optimizationproblem an optimal control is achieved. The MPC controller is evaluated and compared to a conventional controller using simulations. After some tuning the MPC controller is capable of maintaining the inside air and DHW temperature at their reference levels without oscillating too much. The MPC controller’s general performance is quite similar to the conventional controller, but with a power consumption which is 1-3 % lower. A simulation using an inside air temperature reference which is lowered during the night is also conducted, it achieved a power consumption which was 7.5 % lower compared to a conventional controller.
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Salam, Md Abdul y Md Mafizul Islam. "Modelling and Control System Design to control Water temperature in Heat Pump". Thesis, Karlstads universitet, Avdelningen för fysik och elektroteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-30680.
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The thesis has been conducted at Hetvägg AB and the aim is to develop a combined PID and Model Predictive Controller (MPC) controller for an air to water heat pump system that supplies domestic hot water (DHW) to the users. The current control system is PLC based but because of its big size and expensive maintenance it must be replaced with a robust controller for the heat pump. The main goal of this project has been to find a suitable improvement strategy. By constructing a model of the system, the control system has been evaluated. First a model of the system is derived using system identification techniques in Matlab-Simulink; since the system is nonlinear and dynamic a model of the system is needed before the controller is implemented. The data has been estimated and validated for the final selection of the model in system identification toolbox and then the controller is designed for the selected model. The combined PID and MPC controller utilizes the obtained model to predict the future behavior of the system and by changing the constraints an optimal control of the system is achieved. In this thesis work, first the PID and MPC controller are evaluated and their results are compared using transient and frequency response plots. It is seen that the MPC obtained better control action than the PID controller, after some tuning the MPC controller is capable of maintaining the outlet water temperature to the reference or set point value. Both the controllers are combined to remove the minor instabilities from the system and also to obtain a better output. From the transient response behavior it is seen that the combined MPC and PID controller delivered good output response with minimal overshoot, rise time and settling time.
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Christodoulou, Stephen. "Control of a heat-shock gene in yeast". Thesis, University of Kent, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385183.
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Arding, Karin y de Betou Siri In. "Making grid capacity available through heat pump control". Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-384182.
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In this report the problem of constructing a bus depot with electrical buses despite the lack of grid capacity, was analyzed. A potential solution is investigated, namely smart control of heat pumps in industries. The possibility of allocating grid capacity to the bus depot by reducing power consumption in heat pumps during peak hours, is taken into consideration. The maximum amount of released capacity in an industrial area is calculated through the controlling of heat pumps. This investigation was made through simulations with a simplified building energy model (lumped capacity model) which was applied to a reference building. After mapping the area Boländerna and the geothermal wells located there, IKEA Uppsala was chosen as the reference building, since a third of the total number of wells were found in that area. To take the whole capacity of Boländerna into account, the model was scaled up to estimate the total, possible reduction of power. The bus depot requires 6 MW nighttime and 4 MW daytime, the total amount of electrical power that could be withdrawn, if all heat pumps were on maximum heat, in the chosen area were 0.75 MW and by controlling the heat pumps during an optimized level, the amount of 142 kW could be made available to the electric grid. 142 kW is not enough cover the need for the bus depot but it could supply the need for a slow charger to one of the buses and is therefore a possible sub-solution to the larger problem.
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Johansson, Max. "Optimal Control of Heat Transfer Rates in Turbochargers". Thesis, Linköpings universitet, Fordonssystem, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-148734.
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The turbocharger is an important component of competitive environmentally friendly vehicles. Mathematical models are needed for controlling turbochargers in modern vehicles. The models are parameterized using data, gathered from turbocharger testing ingas stands (a flow bench for turbocharger, where the engine is replaced with a combustion chamber, so that the exhaust gases going to the turbocharger can be controlled with high accuracy). Collecting the necessary time averaged data is a time-consuming process. It can take more than 24 hours per turbocharger. To achieve a sufficient level of accuracy in the measurements, it is required to let the turbocharger system reach steady state after a change of operating point. The turbocharger material temperatures are especially slow to reach steady state. A hypothesis is that modern methods in control theory, such as numeric optimal control, can drastically reduce the wait time when changing operating point. The purpose of this thesis is to provide a method of time optimal testing of turbo chargers. Models for the turbine, bearing house and compressor are parameterized. Well known models for heat transfer is used to describe the heat flows to and from exhaust gas and charge air, and turbocharger material, as well as internal energy flows between the turbocharger components. The models, mechanical and thermodynamic, are joined to form a complete turbocharger model, which is validated against measured step responses. Numeric optimal control is used to calculate optimal trajectories for the turbo charger input signals, so that steady state is reached as quickly as possible, fora given operating point. Direct collocation is a method where the optimal control problem is discretized, and a non-linear program solver is used. The results show that the wait time between operating points can be reduced by a factor of 23. When optimal trajectories between operating points can be found, the possibility of further gains, if finding an optimal sequence of trajectories, are investigated. The problem is equivalent to the open traveling salesman, a well studied problem, where no optimal solution can be guaranteed. A near optimal solution is found using a genetic algorithm. The developed method requires a turbocharger model to calculate input trajectories. The testing is done to acquire data, so that a model can be created, which is a catch-22 situation. It can be avoided by using system identification techniques. When the gas stand is warming up, the necessary model parameters are estimated, using no prior knowledge of the turbocharger.
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Michaela, Hillerström y Ludvig Wingårdh. "Solar Radiation Prediction for Heat Pump System Control". Thesis, KTH, Energiteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-233171.
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Detta kandidatexamensarbete fokuserar på indirekt mätning av solstrålning där en förbättring av en värmepump i ett bostadshus var huvudfokus. Detta utan att använda redan existerande utrsutning för mätning av solstrålning - pyranometrar- då denna utrustning är relativt dyr. För att genomföra detta projekt har en litteraturstudie gjorts där artiklar om indirekt mätning eller förutsägelse av solstrålning har studerats. Både konventionella metoder och nyare metoder som använder sig utav maskininlärning har varit en del av litteraturstudien. En redan befintlig metod för att förutse strålningseffekten per kvadratmeter baserad på data över molnighet har modifierats för att uppnå högre energisparande vid användning för ökad kontroll av en värmepump. Tre olika modeller togs fram som förslag på utveckling av den befintliga modellen. En baserad på olika intervaller av procent av molnighet, en som kompenserade för den redan befintliga modellens systematiska underskattning av de högsta dygnsvärdena av solstrålning och en diskret funktion. Den tredje modellen uppnådde energibesparingar på 18% utan att försämra inomhusklimatet med avseende på temperatur. Från redan existerande litteratur och från resultaten av analysen av den modifierade modellen är det tydligt att det går att mäta solstrålning indirekt eller förutse solstrålning med tillräcklig noggranhet för att kunna uppnå 10-20% energibesparingar i ett värmepumpssystem för ett bostadshus.This bachelor of science thesis focuses on indirect measurement of solar radiation. The perspective of the thesis is improving the performance of a heat pump in a residential building without the use of existing dedicated equipment for measuring solar radiation – pyranometers – because of the relatively high cost. A literature review has been performed, where articles on the subject of indirectly measuring or predicting solar radiation have been included. Both conventional methods as well as newer methods using machine learning have been part of the review. An existing method for predicting irradiance based on cloud cover percentage has been modified in attempt to achieve higher energy savings when used for improving control of a heat pump. Three different models were suggested. One based on different ranges of cloud cover percentages, one that compensated for the existing models systematic underestimation of peak-hour solar values, and one discrete function model. The first two models resulted in slight improvements of condenser energy use. The third model provided energy savings of 18% without worsening thermal comfort, compared to not compensating for solar radiation. From existing literature, and from the results of the analyzed and modified model, it is evident that solar radiation can be measured indirectly or forecasted with sufficient accuracy to achieve energy savings of the magnitude of 10-20% when considering a heat pump system in a residential building.
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Chowdhury, Jahedul Islam. "Modelling and control of waste heat recovery system". Thesis, Queen's University Belfast, 2017. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.725593.
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This research focuses on the waste heat recovery (WHR) from low and medium grade heat sources, and its conversion into mechanical rotations and electrical energy using organic Rankine cycle (ORC), in automotive and industrial applications. The research outcomes include: (1) development of subcomponent models including a novel fuzzy based evaporator model of the supercritical ORC-WHR system using thermodynamic and numerical methods in MATLAB/Simulink, (2) overall ORC-WHR integration and complete system simulation to improve thermal and heat recovery efficiency in steady state and dynamic conditions, (3) investigation of the system performance with respect to stationary and mobile heat sources, (4) transient response analysis and dynamic simulation of the ORC-WHR system with respect to low and medium grade heat sources, (5) development of appropriate control strategies for the high thermal inertia and slow response ORC-WHR system, (6) development of a novel control algorithm to improve control performance of conventional controllers in WHR systems, (7) control system simulation to improve the operational performance, continuity, and safety of the system under steady and transient heat input conditions.
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End, Thomas [Verfasser]. "Optimal Control of Nonlocal Radiative Heat Transfer / Thomas End". München : Verlag Dr. Hut, 2012. http://d-nb.info/1021072893/34.
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Hepworth, Simon. "Hybrid neural control of heat exchangers in HVAC plant". Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260138.
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Johnson, Tim. "Heat treatments to control fungal skin diseases of potato". Thesis, University of Essex, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.435255.
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Yousefi, Darani Shahrokh. "Control and Automation of a Heat Shrink Tubing Process". Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc699928/.
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Heat shrink tubing is used to insulate wire conductors, protect wires, and to create cable entry seals in wire harnessing industries. Performing this sensitive process manually is time consuming, the results are strongly dependent on the operator’s expertise, and the process presents safety concerns. Alternatively, automating the process minimizes the operators’ direct interaction, decreases the production cost over the long term, and improves quantitative and qualitative production indicators dramatically. This thesis introduces the automation of a heat shrink tubing prototype machine that benefits the wire harnessing industry. The prototype consists of an instrumented heat chamber on a linear positioning system, and is fitted with two heat guns. The chamber design allows for the directing of hot air from the heat guns onto the wire harness uniformly through radially-distributed channels. The linear positioning system is designed to move the heat chamber along the wire harness as the proper shrinkage temperature level is reached. Heat exposure time as a major factor in the heat shrink tubing process can be governed by controlling the linear speed of the heat chamber. A control unit manages the actuator position continuously by measuring the chamber’s speed and temperature. A model-based design approach is followed to design and test the controller, and MATLAB/Simulink is used as the simulation environment. A programmable logic controller is selected as the controller implementation platform. The control unit performance is examined and its responses follow the simulation results with adequate accuracy.
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Meyer, Antoine. "Active control of heat transfer by an electric field". Thesis, Normandie, 2017. http://www.theses.fr/2017NORMLH13/document.
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La stabilité d’un fluide Newtonien diélectrique confiné dans un anneau cylindrique et soumis à un gradient radial de température et à un champ électrique est étudiée. Le gradient de température induit une stratification de la permittivité électrique du fluide et de sa masse volumique. Trois poussées thermiques rentrent alors en jeu : la gravité terrestre créée la poussée d’Archimède, la rotation des cylindres engendre la poussée centrifuge, et le champ électrique induit la poussée diélectrophorétique. L’effet de ces poussées est étudié dans différentes combinaisons, principalement à travers l’étude de la stabilité linéaire, mais également par la simulation numérique directeThe stability of a Newtonian dielectric fluid confined in a cylindrical annulus and submitted to a radial temperature gradient and an electric field is studied. The temperature gradient induces a stratification of the electric permittivity and of the density. Thus three thermal buoyancies intervene: the Earth gravity creates the Archimedean buoyancy, the rotation of the cylinders generates the centrifugal buoyancy, and the electric field induces the dielectrophoretic buoyancy. The effect of these buoyancies is studied in different combination, principally through the linear stability analysis, but also by direct numerical simulation
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Verrax, Paul. "Model Predictive Control Applied to Ground Source Heat Pumps". Thesis, KTH, Reglerteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-224330.
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Building heating is one of the most important sources of energy consumption. GroundSource Heat Pumps (GSHP) are efficient heating systems, particularly popular in the Nordiccountries. However, the GSHPs available for the consumer market today typically only utilizebasic control schemes that are relatively inflexible. More advanced strategies such as ModelPredictive Control (MPC) appear as a promising approach to improve comfort while reducingconsumption. The present thesis considers a typical user case of a single family house heatedby a ground source heat pump willing to reduce its environmental impact. We design a MPCcontroller to be used on top of the existing heat pump system and with almost no additionalhardware needed. Specific attention is dedicated to the system’s efficiency in order to reflectthe real working performances of a ground source heat pump. The controller is evaluated insimulation on different scenarios using an identified model of a single family house. The resultsshow the MPC strategy becomes most beneficial when including time varying prices or reducedcomfort during certain hours of the day. When both are conjugated the economic savings areup to 8% despite the loss of efficiency of the heat pump. The controller was implemented andtested on a real system with promising results.Uppvärmning av byggnader är en av samhällets största energiförbrukare. I Norden användsofta bergvärmepumpar som ett effektivt alternativ för uppvärmning. De flesta bergvärmepumparstyrs av väldigt enkla algoritmer. Model Predictive Control (MPC) är en lovande metodför att ta hänsyn till både inomhustemperatur och energiförbrukning, speciellt om man hartillgång till en väderprognos. Denna rapport studerar hur ett typiskt enfamiljshus kan minskasin energiåtgång och miljöpåverkan. Ansatsen är att lägga till ett yttre reglersystem till bergvärmepumpen.Speciell vikt läggs vid modellering av bergvärmepumpens effektivitet. Olikascenarion jämförs, bland annat att ta hänsyn till elprisets variation över dygnet med hjälpav ekonomisk MPC. Simuleringar visar att användning av MPC är mest fördelaktig i det fallbåde elpriset och krav på innetemperatur varierar över dygnet. I sådana fall kan energikostnadenminska med upp till 8%, trots att bergvärmepumpen stundtals arbetar i ett ogynnsamtdriftläge. Ett verkligt system har använts för systemidentifiering och experiment med en MPCregulator.
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Boonsrang, Direcksataporn. "A study on the dynamic characteristics and control of heat exchangers in waste heat recovery systems /". Electronic version of summary, 1992. http://www.wul.waseda.ac.jp/gakui/gaiyo/1797.pdf.
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Govindaraj, Thavamani. "Optimal Control of a Stochastic Heat Equation with Control and Noise on the Boundary". Thesis, Linnéuniversitetet, Institutionen för matematik (MA), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-76037.
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In this thesis, we give a mathematical background of solving a linear quadratic control problem for the heat equation, which involves noise on the boundary, in a concise way. We use the semigroup approach for the solvability of the problem. To obtain optimal controls, we use optimization techniques for convex functionals. Finally we give a feedback form for the optimal control. In order to enhance understanding of linear quadratic problem, we first present the methods in deterministic cases and then extend to noisy systems.
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Bakhurji, Khalid A. "Cascade control for a steam-heated double-pipe heat exchanger". Thesis, California State University, Long Beach, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1596967.
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The goal of this thesis is to create the experimental setup and the necessary instrumentation for the temperature control of a double-pipe heat exchanger. The heat exchanger, located at the Chemical Engineering Control Laboratory at the California State University, Long Beach, has been used in the past for temperature control experiments, in which the manipulated variable was the incoming water flow. In the control experiments performed for the current work, the manipulated variable is the incoming steam pressure. For this purpose cascade control has been used, with an inner loop controlling the steam pressure setpoint, and an outer loop controlling the water outlet temperature. Despite major fluctuations in the steam pressure supply and inappropriate sizing of a control valve, the experimental results show that the designed cascade control can track the temperature setpoint and reject load-induced disturbances satisfactorily. System parameters are obtained via experimental modeling through open loop experiments. A LabView-based data acquisition and control program has been written and implemented for acquiring and processing sensor outputs, and for providing control commands to the final control elements. Several controller parameter tuning methods, such as IMC, ITAE, Cohen-Coon, and Ziegler-Nichols, were implemented and evaluated experimentally through a set of performance indices.
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Mengod, Bautista Fernando. "Propane Heat Pump Modelling and Monitoring for System Control Analysis". Thesis, KTH, Tillämpad termodynamik och kylteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-250669.
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The objective of this master thesis was the performance analysis of a non-conventional heating system layout based on a propane heat pump unit. The objective had been pursued by monitoring and modelling the system. First, the project focused on monitoring the system, since for a correct modelling it was necessary to have all the data of the system. For this, the first step was to identify the necessary variables for the complete analysis, being temperatures and pressures as necessary as data for the calculation of power, flows and energetic analyses. The system, located in Åkersberga (Sweden), was instrumented for monitoring purposes with a combination of ClimaCheck solution and prototypes of low-cost wireless temperature sensors designed and developed at KTH Energy Technology lab. The second phase of the project was the collection of this data as well as its storage, these measures that also include multiple weather sources of ambient temperatures, relative humidity, wind speed and solar radiation are collected in a database. In addition, a web interface had been developed at KTH for displaying and processing the measurements. Once the installation was correctly monitored, the project focused on the modelling of the installation. The Heat Pump unit was modelled by means of IMST-ART. IMST-ART is an advanced software developed by the Polytechnic University of Valencia for the analysis and optimization of refrigeration equipment and components. With IMST-ART, therefore, the construction of a model with which to obtain results that approximates as much as possible to the data measured in the installation was carried out. IV The model of the heating systems was modelled by means of TRNSYS. This model included the heat pump, previously modelled with IMST-ART, the two storage tanks and all the other components of the system. Finally, this model was used to perform a parametric study to investigate the possibility of adopting this system layout to a system with storage tanks of more conventional sizes. So, starting from a system layout that was the result of a partial heating system renovation, after analysing the performance through the monitoring and modelling activity, a parametric study was performed to analyse the system performance with focus on possible improvement of the system control and optimization of components.Syftet med detta examensarbete var att utföra en prestationsanalys av ett icke-konventionellt uppvärmningssystem utformat på en propanvärmepumpenhet. Projektet har bedrivits genom övervakning och modellering av systemet. Först, fokuserade projektet på att övervaka systemet. Detta var nödvändigt för att ha alla data i systemet för korrekt modellering. Övervakning var det första steget i att identifiera de nödvändiga variablerna för den fullständiga analysen. Temperatur och tryck är nödvändiga indata för beräkning av effekt, flöden och energiska analyser. Systemet, som ligger i Åkersberga (Sverige), hade instrument för övervakning som utgjordes av en kombination på en ClimaCheck-lösning och prototyper av billiga trådlösa temperatursensorer konstruerade och utvecklade på KTH Energy Technology. Den andra fasen av projektet var insamlingen av dessa data samt dess lagring. Insamlingen innehåller också flera källor för vädermätningar av omgivande temperaturer, relativ fuktighet, vindhastighet och solstrålning samlas i en databas. Därtill ett webbgränssnitt som har utvecklas av KTH för att visa och bearbeta mätningarna. När installationen var korrekt övervakad, fokuserade projektet på modellering av installationen. Värmepumpenheten modellerades med hjälp av IMST-ART. IMST-ART är en avancerad programvara utvecklad av Polytechnic University of Valencia för analys och optimering av kylutrustning och komponenter. Med IMST-ART utfördes därför konstruktionen av en modell för att erhålla resultat som approximerar så mycket som möjligt till de data som mättes i installationen. Modellen av värmesystemen modellerades med hjälp av TRNSYS. Denna modell inkluderade värmepumpen, tidigare modellerad med IMST-ART, de två lagringstankarna och alla andra komponenter i systemet. Slutligen användes denna modell för att utföra en parametrisk studie för att undersöka möjligheten att anta denna systemlayout till ett system med lagringstankar av mer konventionella storlekar. Så, från en systemlayout som var resultatet av delvis återställning av uppvärmningsystemet, efter att ha analyserat prestanda genom övervaknings- och modelleringsaktiviteten, genomfördes en parametrisk studie för att analysera systemets prestanda med fokus på möjliga förbättringar av systemstyrning och optimering av komponenter
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Calandranis, John Christos. "Operability studies in heat exchanger networks : analysis, control and synthesis". Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/14393.
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Melani, Barreiro Diego A. "A small satellite preliminary thermal control and heat shield analysis". Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/43020.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, February 2008.Includes bibliographical references (leaf 23).
As part of a student owned small satellite project, a preliminary thermal control and heat shield analysis was developed to verify acceptable performance requirements for the system. For the thermal control section, the analysis was focused on the Bus module of the satellite. It measured the effects of the Sun and Eclipse periods at low earth orbit (LEO), accounted key design and subsystems interaction considerations and indicated some of the structural parameters available for its success. As for the heat shield section, calculations were made to quantify the magnitude of the heat flux going into the payload capsule. The thermal control analysis was implemented to determine if the radiator area and insulation from the aluminum honeycomb structure were sufficient to maintain the electronic components at proper operating temperatures during the mission. Materials such as insulating coating paints and mechanisms such as heaters were researched and considered as additional thermal protection barriers. Thermal subsystems interfaces, i.e. Bus-Return Vehicle Interface, were also analyzed. Models for the incoming heat across the Ablator heat shield were used to determine values for transient and steady-state heating and cooling scenarios. These provided indications of the incoming and outgoing heat transfers into and out of the payload module. With the use of thermal resistance models, values for the heat transfers were obtained. This study interpreted the thermal effects of orbiting Earth at LEO for the Bus module of a small satellite. It also measured the effectiveness of the heat shield on preventing incoming heat transfers into the payload module. From proper approximations, realistic results were obtained for both cases. Though no in depth analysis was performed, actual values obtained for the heating effects provided a valid scope of the overall effects on the system.
by Diego A. Melani Barreiro.
S.B.
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Horrell, Judith Ann. "Translational control of the heat shock response in Xenopus oocytes". Thesis, University of Warwick, 1988. http://wrap.warwick.ac.uk/99025/.
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It has been suggested that the heat shock response of Xenopus oocytes might provide a good model system to study the regulation of translation in early development: oocytes were thought to contain a store of hsp70 mRNA, which was unmasked reversibly on heat shock. However, more recently it has been reported that the hsp70 apparently synthesized in oocytes is in fact made entirely in the attached follicle cells. A method was developed to reliably remove follicle cells. Two-dimensional gel analysis of radioactively labelled oocytes revealed that, although hsp70 was the major protein synthesized during heat shock if follicle cells were present, it could not be detected if these cells were removed. Oocytes do contain up to 15pg of hsp70 mRNA; it is not clear if this is translated. In some experiments synthesis of a group of proteins was induced in oocytes during heat shock, but none was hsp70. To test whether oocytes can synthesize hsp70, plasmids encoding Xenopus hsp70 genes were injected. These were transcribed efficiently, yielding RNA that was indistinguishable in length and polyadenylation status from heat-induced transcripts in follicle cells. Synthesis of hsp70 was detected in defol1iculated, injected oocytes: it was translated well even during heat shock (when translation of other mRNAs was greatly reduced), suggesting that oocytes regulate translation of exogenous transcripts appropriately. Surprisingly, flu nucleoprotein RNA transcribed in oocytes was also preferentially translated during heat shock in some experiments. The 5' leaders of hsp70 and NP RNAs contain a region of homology. As injection of RNA provides a more direct way of controlling transcript levels in oocytes, polyadenylated RNA encoding hsp70 was transcribed in vitro (from a variety of templates) and injected into oocytes. Products of a hsp70/globin fusion and a truncated hsp70 gene were never detected. Native hsp70 was synthesized, but it was not made preferentially during heat shock. Similarly, when influenza NP mRNA was injected, preferential translation was never observed. It appears therefore that exogenous RNA is regulated appropriately during heat shock when it is introduced by the route of DNA injection, but not when RNA itself is injected.
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Byström-Troyan, Filipp. "Heat and fluid control solutions for deep space CubeSat CGPS". Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-303116.
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This thesis is on the subject of how propellant heating considerations affect the design of a CubeSat cold gas propulsion system. Computer simulation tools are used to analyse heat flow through the system, as well as the fluid flow and phase change of butane. The heating performance is presented for different operational states and different designs. Finally, an optimal system design is suggested. The propulsion system in question is the deep space heading Hera Juventas 6DOF CGPS. The Juventas spacecraft will as part of ESA’s Hera mission be the first to perform radar measurements of an asteroid. It will determine the result of the NASA DART mission and will give insights to the internal structure of the Dimorphos minor- planet moon.Detta examensarbete behandlar utformningen av ett CubeSat kallgasframdrivningssystem med avseende på drivmedelsuppvärmning. Datorsimuleringsverktyg används för att analysera värmeflöde genom systemet samt flödet och fasförändringen av butan. Värmningsprestanda presenteras för olika driftstillstånd och olika konstruktioner. Slutligen föreslås en optimal systemdesign. Framdrivningssystemet i fråga är Hera Juventas 6DOF CGPS. Rymdfarkosten Juventas kommer som en del av ESA:s Herauppdrag att vara den första som utför radarmätningar av en asteroid. Den kommer att avgöra resultatet av NASA:s DARTuppdrag och kommer att ge insikter om den interna strukturen i asteroidmånen Dimorphos.
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Ščepka, Ondrej. "Měřící a řídicí systém pro tepelné čerpadlo". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2019. http://www.nusl.cz/ntk/nusl-400600.
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This master thesis describes the issue of the measuring and control system for the heat pump. In the first part of the thesis is described the principle of heat pump activity, its basic components. The second part contains the distribution of heat pumps according to the method of obtaining and transferring the heat. The following chapter contains the description of system status before the modernization. In the practical part of this thesis is the proposal and realization of new control and monitoring system including the description of individual components. In the conclusion of the thesis is a verification of the use of proposed control and monitoring system of heat pump for the measuring of its operational characteristics.
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Vayena, Olga. "Distributed parameter control in rapid thermal processing (RTP) /". Thesis, Connect to Dissertations & Theses @ Tufts University, 2004.
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Thesis (Ph.D.)--Tufts University, 2004.Adviser: Haris Doumanidis. Submitted to the Dept. of Mechanical Engineering. Includes bibliographical references (leaves 123-129). Access restricted to members of the Tufts University community. Also available via the World Wide Web;
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Denker, Richard. "Dimensioning and control for heat pump systems using a combination of vertical and horizontal ground-coupled heat exchangers". Thesis, Karlstads universitet, Institutionen för ingenjörsvetenskap och fysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-36475.
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A model has been developed which simulates a system consisting of a horizontal and vertical ground-coupled heat exchanger connected in parallel to the same heat pump. The model was used in computer simulations to investigate how the annual minimum and mean fluid temperatures at the heat pump varied as several parameters of the combined system were changed. A comparison was also made between different control settings for fluid flow rate distribution between the two exchangers. For the case when the flow rate distribution was not controlled, the effect of viscosity differences between a colder and warmer exchanger was investigated. The short term effects of letting the vertical heat source rest during the warm summer months was then tested. Lastly, the results of the model was compared to a simple 'rule of thumb' that have been used in the industry for this kind of combined system. The results show that using a combined system might not always result in increased performance, if the previously existing exchanger is a vertical ground-coupled heat exchanger. The effects of viscosity differences on the flow distribution seems to be negligible, especially for high net flows. Controlling the fluid flow rates seems to only be worth the effort if the the pipe lengths of the two combined exchangers differ heavily. Letting the vertical ground-coupled heat exchanger rest during summer was shown to in some cases yield an increased short-term performance in addition to the already known positive long term effects. The rule of thumb was shown to recommend smaller dimensions for combination systems than the more realistic analytical model.
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El, Sachat Alexandros. "Characterization of nanostructured materials for thermal conduction and heat transfer control". Doctoral thesis, Universitat Autònoma de Barcelona, 2017. http://hdl.handle.net/10803/405520.
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L'objectiu principal d'aquesta tesi és l'estudi de les propietats tèrmiques de materials nanoestructurats com un mitjà per controlar el transport de calor. Per a aquest propòsit s’han portat a terme mesures tèrmiques amb diferents tècniques experimentals a escales que cobreixen desenes de micròmetres fins a per sota de 50 nanòmetres. En aquest tesi s’estudien i es presenten dues tècniques experimentals en particular: (a) la microscòpia tèrmica d’escombrat (SThM) i (b) la termometria Raman amb dos làsers (2LRT). Aquestes tècniques s'han aplicat àmpliament per mesurar amb èxit propietats tèrmiques en diversos nanomaterials. En particular, s'investiguen dues configuracions del silici emprant 2LRT: (a) membranes de silici amb gruixos que van de 8 a 1000 nm i (b) membranes poroses periòdiques amb diferents paràmetres de xarxa i membranes amb patró desordenat. Els resultats obtinguts han mostrat que la conductivitat tèrmica en el pla de les membranes i la seva evolució en temperatura, des de la temperatura ambient a aproximadament 1000 K, es poden reduir i ajustar de manera eficaç per mitjà de (i) el gruix i (ii) el patró periòdic(forats). Atribuïm la reducció de la conductivitat tèrmica a l'escurçament del camí lliure dels fonons a causa de la dispersió difusa (incoherent) fonó en els límit de les superfícies. Hem demostrat a més que la dependència de la conductivitat tèrmica amb la temperatura en l’interval d'alta temperatura (400 a 1000 K) es regeix per fonons amb el camí lliure mitjà menor que 200 nm. Per investigar el transport tèrmic en nanoestructures suportades i a escala més petita, s’ha estudiat la transferència de calor entre sensors de sonda d’escombrat escalfats i els nanomaterials, com ara, (i) nanofils epitaxials en el pla d’aliatge Si1-xGex i (ii) nanoestructures basades en copolímer de blocs autoassemblats. En aquestes últimes estructures s’han aconseguit imatges tèrmiques d'alta resolució en estructures de mida per sota de 50 nm i amb resolució espacial per sota de 20 nm. La combinació de les dues tècniques experimentals ha estat crucial per a la caracterització tèrmica dels diferents sistemes de materials i la millor comprensió dels aspectes fonamentals del transport tèrmic.The main objective of this thesis is the study of thermal properties of nanostructured materials as a mean to control heat transport. For this purpose thermal measurements with different experimental techniques on length scales covering tens of microns to sub-50 have been performed. Two experimental techniques in particular have been studied and presented in this thesis: (a) the scanning thermal microscopy technique (SThM) and (b) the two-laser Raman thermometry (2LRT). These techniques have been extensively applied to successfully measure thermal properties in various nanomaterials. In particular, two configurations of Si based materials are investigated using 2LRT: (a) Si membranes with thicknesses ranging from to and (b) periodic porous membranes with different lattice parameters and disordered pattern. The results obtained showed that the in-plane thermal conductivity of silicon and its temperature evolution from room temperature to about 1000 can be effectively reduced and tuned by (i) thickness and (ii) periodic patterning (holes). We attribute the reduction of the thermal conductivity to the shortening of the phonon mean free path Λ due to diffuse (incoherent) phonon-boundary scattering. Furthermore, we showed that the temperature dependence of the thermal conductivity of Si membranes in the high temperature range from to is governed by phonons with mean free path smaller than 200 . To investigate thermal transport in supported nanostructures and in smaller length scale, we studied heat transfer between different heated scanning probe sensors and nanomaterials, such as, (i) in-plane epitaxial Si1-xGex alloy nanowires and (ii) self-assembled block copolymer nanostructures, provided high resolution thermal images of sub-50 structures with sub- spatial resolution. The combination of the two experimental techniques was crucial for the thermal characterization of different material systems and the better understanding of fundamental aspects of thermal transport.
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DeRocher, Amy Elizabeth. "Developmental control of heat shock protein expression during pea seed maturation". Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186151.
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Heat shock proteins (HSPs) are strongly conserved families of proteins induced when an organism is exposed to elevated temperatures. I have studied the expression of two of these protein families, small (s) HSPs and HSP70s in pea (Pisum sativum). Both protein families are induced during seed maturation in addition to being expressed in response to elevated temperatures. Class I cytoplasmic sHSP mRNAs are strongly induced in response to heat stress, comprising over 1% of the mRNA population. HSPs are strongly induced by environmental conditions mimicking conditions plants would experience on hot days. Antiserum raised against a class I sHSP fusion protein detects eight polypeptides in protein from heat stressed leaves. These peptides are induced at leaf temperatures as low as 29°C, and comprise approximately 1% of the SDS soluble protein in 38°C heat stressed leaves, and have a half-life of 38 hours. The low induction temperature and extended half-life of these proteins suggests that they have an important role in the plant life cycle. HSPs are also developmentally regulated during seed maturation, even though the tissue temperature is 10°C below the heat stress induction temperature. Both class I and class II cytoplasmic sHSP mRNAs and proteins accumulate during mid-maturation in cotyledons and during desiccation in axes, and persist in the mature, dry seeds. The amount of protein that accumulates in the maturing seeds is comparable to that induced by a moderate, 34°C, heat stress. Additional sHSPs accumulate if seeds are heat stressed. sHSPs persist for two to three days in germinating seeds. Only five of eight class I sHSP polypeptides accumulate in maturing seeds, and only three of four class II sHSPs are developmentally regulated. HSP70-family proteins are also developmentally regulated during seed maturation. The heat induced mRNA, PsHSP71.2, is coordinately regulated with sHSPs, while a constitutively expressed mRNA, PsHSC71.0, is present throughout seed maturation. The amount of another constitutively synthesized HSP70 mRNA, PsHSP70b, declines in cotyledons as seed maturation progresses. These data suggest that HSPs have a specific role in seed maturation in addition to their role in response to heat stress.
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Kim, Minsoo. "Protein Quality Control, Redox Balance and Heat Stress Tolerance in Arabidopsis". Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/217060.
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The Arabidopsis HSP101 protein belongs to the Hsp100/ClpB family of AAA+ proteins (ATPases Associated with various cellular Activities). This family of proteins, in collaboration with the Hsp70 chaperone system, has the remarkable ability to solubilize protein aggregates and refold proteins back to their native forms. Thus, their chaperone activity is necessary for acquired thermotolerance in organisms as diverse as bacteria and plants. My dissertation project focused on understanding the mechanism of HSP101 action using Arabidopsis thaliana as a model system. The first approach used genetics to screen for suppressors of a specific missense mutant allele of HSP101, hot1-4, in order to find interacting cofactor proteins or key substrates of HSP101, or other processes involved in thermotolerance. Four extragenic suppressors that can overcome the heat-hypersensitive phenotype caused by the hot1-4 mutation were isolated and one of them (shot1) was identified as a mutation in a mitochondrion-targeted protein. Although shot1 mutations do not directly interfere with HSP101 function, they reveal independent mechanisms required for thermotolerance, which involve reduced oxidative stress. The second approach used to investigate HSP101 function was to affinity-purify HSP101 and identify associated proteins. For this purpose, transgenic Arabidopsis plants were generated expressing affinity-tagged wild-type and mutant variants of HSP101. As predicted, cytosolic Hsp70s were identified as an interacting partner of HSP101. Surprisingly, 26S proteasome regulatory subunits were also identified, suggesting a possible link between the protein degradation and reactivation pathways. Further experiments were also undertaken to define the importance of different domains of HSP101, as well as the localization of HSP101. Transgenic Arabidopsis plants expressing N- or C-terminally truncated HSP101 indicate that the N-terminal domain of HSP101 is required for full activity in protecting plants from heat stress. However, in contrast to the yeast ortholog, Hsp104, the C-terminal extension of HSP101 was found to be completely dispensable for thermotolerance of Arabidopsis. Additional transgenic plants expressing an HSP101-GFP were also characterized. Initial microscopic analysis confirms nuclear/cytoplasmic localization as has been reported previously for yeast Hsp104. However, the dynamics of subcellular redistribution upon heat stress need to be further investigated to fully understand the potential significance of the observed localization.
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Chant, Eileen Elizabeth. "Transient and steady state simulations of an advanced desiccant enhanced cooling cycle". Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/17846.
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Hanses, Jonathan y Morten Eriksson. "Modelling and Control of Heat Distribution in a Powder Bed Fusion 3D Printer". Thesis, Linköpings universitet, Reglerteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-159792.
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This thesis report describes how to improve the control of the temperature in a Powder Bed Fusion 3D printer. This is accomplished by first creating a model ofthe thermal system. To create a good model, both black-box and grey-box models of the system are estimated and compared. Based on the best model, different control designs are examined and the results are compared to find the control design yielding the best results. The system being modelled is a multiple input multiple output system with acomplex internal structure. The modelling can be divided into several steps. Firstly, data has to be acquired from the system. Secondly, the data is analysed and processed. Thirdly, models are estimated based on the collected data. Different model structures such as state-space, ARX, ARMAX, Output Error, Box Jenkins and grey-box models are examined and compared to each other. Finally, the different derived models are validated and it turns out the ARMAX model yields the best prediction capabilities. However, when the controllers were tested on the actual system the controllers that are based on the grey-box model yield the best results. The different control designs examined in this work are diagonal PI controllers, decoupled PI controllers, feed forward controllers, IMC controllers and statefeedback controllers. The controllers are all based on the derived models. The controllers are implemented into a code structure capable of communicating with the printers. Here, tests of the performance for the different controllers on the actual system are executed. The results show that a non-linear system can be controlled using linear controllers. However, introducing some fuzzy control elements such as limiting the controllers to only be used within small temperature intervals and using a fixed input outside this interval yield better results. From these results, the best linear controller is a diagonal PI controller tuned from a grey-box model with as many states as there are controllable areas of the powder bed. The improvement is only marginal compared to the original PI controller, reinforcing the conclusion that some non-linear strategies are needed in the controller in order to achieve significant improvements.
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Youssef, Walid Mohamed Khalil Abdalla. "Experimental and computational study of indirect expansion solar assisted heat pump system with latent heat storage for domestic hot water production". Thesis, Brunel University, 2017. http://bura.brunel.ac.uk/handle/2438/15263.
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Solar assisted heat pump (SAHP) systems have been widely applied in domestic hot water (DHW) production due to their sustainability and stability in operations. However, their performance efficiency requires further improvement using advanced technologies such as energy storage with phase change materials (PCM) and optimal system controls. Undoubtedly, employing PCMs for latent heat storage (LHS) application has a great potential to improve a solar thermal application performance. Despite this fact, the use of PCM in this area is quite limited due to the poor thermal conductivity of available PCMs. Therefore, heat transfer enhancement is one of the essential strategies that can overcome this obstacle. Accordingly, a test rig of a new indirect expansion solar assisted heat pump (IDX-SAHP) system has been designed, built and instrumented. The system can handle heating capacity up to 9 kW. The IDX-SAHP system consists of three operational loops: solar thermal, solar-air assisted heat pump and load profile. A 2 kW PCM heat exchanger (HX) was purposely designed and installed in the system solar thermal loop to store solar energy, when applicable, and release heat when required by the heat pump. The PCM HX is employed with a novel heat transfer enhancement method. The maximum coefficient of performance (COP) of the IDX-SHAP system reached 4.99 during the sunny day with the PCM (HX) integration. However, the maximum energy saving was achieved during the cloudy day with the PCM HX integration. Moreover, the proposed heat transfer enhancement method has been modelled through CFD package and validated with the experimental results. This allows a clear understanding of the reasons for the longer discharging process compared with the charging process. Furthermore, the inlet flow rate and temperature variation of the PCM HX was simulated during charging and discharging processes. The optimum inlet flow rate for this application was found at 0.1 kg/s while the optimum inlet temperature was found at 40°C. Meanwhile, the whole system was modelled by the coupling of TRNSYS, EES and CFD to investigate the potential and advantages of using the system in locations with rich solar intensity such as Cairo and Madrid. The simulation shows that the solar thermal operation loop was called more frequently in these locations. This had a significant impact on the system energy consumption, especially during winter. The maximum COP and solar performance factor (SPF) of the modelled system were 5.3 and 0.83 respectively.
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Farson, Dave F. "Control of arc weld thermal cycles". The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu1387446228.
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Delatore, Fabio. "Controle multivariável em redes de trocadores de calor com bypasses". Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/3/3139/tde-13072011-145446/.
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Atualmente, existe uma grande variedade de metodologias de controle que poderiam ser utilizadas e aplicadas a processos industriais. Algumas destas metodologias têm um projeto complexo, exigindo um estudo extra de engenharia para projetar um controlador com um desempenho excelente. Outros controladores não apresentam um desempenho tão bom, embora apresentem um projeto extremamente simples. Entre a mais simples e a mais complexa metodologia, existem soluções de controle intermediárias, baseadas nas teorias de controle ótimo, que apresentam uma relativa simplicidade de projeto combinada com um desempenho superior. A presente tese apresenta a aplicação de duas técnicas de controle aplicadas a uma Rede de Trocadores de Calor (RTC) com bypasses: o controle LQR (Regulador Linear Quadrático) e o controle H-Infinito, apresentando os resultados obtidos em simulação no Matlab/Simulink e também resultados experimentais. Além disso, foi desenvolvido um procedimento para a validação experimental de um modelo matemático do trocador de calor casco e tubo 1-1 proposto por NOVAZZI (2006). A obtenção dos resultados experimentais foi realizada através de uma RTC em escala piloto, projetada e construída no Laboratório de Engenharia Química do Centro Universitário da FEI, com a instrumentação necessária e devidamente interconectada a um computador PC através de uma placa de aquisição de dados. A simulação e os ensaios experimentais realizados com os controladores LQR e H-Infinito aplicados na RTC apresentaram resultados adequados quando comparados à dinâmica da RTC em malha aberta (600s.), pois exigiram em torno de 200s. para impor uma mudança de setpoint ou rejeitar os distúrbios aplicados na vazão fria e na temperatura quente de entrada. Além disso, os controladores foram capazes de eliminar as interações entre as variáveis de processo.Nowadays, there are a lot of different control methodologies that could be used on industrial processes. Some of these methodologies have a complex design and also demands an extra engineering effort to design the controller with a superior performance. Some other controllers may not lead to a desirable performance although they are too easy to design. Midway between the simplest and the most complex controller designs, there are an intermediate solutions based on optimal control theory, that present a relative simplicity in design combined with a superior performance. The contribution of this work is to apply the LQR control (Linear Quadratic Regulator) and the H-Infinity control on a Heat Exchanger Network (HEN) with bypasses, presenting the simulations and the experimental results. An experimental validation of the shell and tube heat exchanger mathematical model was successfully developed based on a procedure proposed. The experimental results were obtained with an HEN assembled on the Chemical Engineering Laboratory located at Centro Universitario da FEI. The instrumentation was adequately performed and the signals were interconnected on PC computer by using a data acquisition card. The simulation and the experimental results with the LQR and the H-Infinity control demanded 200s. to achieve a new steady state hen disturbances or set point variation were applied on the HEN. Compared with the HEN setting time (600s.), the controllers demonstrated reasonable results to perform a disturbance rejection and a set point variation.
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Almajali, Mohammad Rajab. "ENGINEERED CARBON FOAM FOR TEMPERATURE CONTROL APPLICATIONS". University of Dayton / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1271365522.
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Fillius, James B. "An experimental study of steady state high heat flux removal using spray cooling". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Dec%5FFillius.pdf.
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Eriksson, Mikael y Oskar Graffman. "Modelling and Simulation of Heat Pump Systems for Hybrid and Electrical Vehicles". Thesis, Linköpings universitet, Fordonssystem, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-149993.
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Hybridization and electrification of modern vehicles is today a reality. This effects the construction of the heating and cooling systems in vehicles where earlier the waste heat from the combustion engine was a great heat source. Heat pump systems are commonly used in heating systems in buildings and can therefore also be used for heating the cabin and different components in a vehicle. Modelling a heat pump system and performing simulations gives the advantage of investigating the heating performance of the heat pump during certain conditions. In this master thesis, which is performed in a pre-study project that is performed under the Swedish Electromobility Centre, a heat pump is modelled and the heating performance when changing the vapour quality is investigated during cold environments. Also how the heating capacity for different refrigerants and changing size and speed of compressor is simulated. With the methods and assumptions used, especially isentropic compression, the results shows that decreasing the vapour quality increase the mass flow in the heat pump circuit but the decrease in specific heating is larger which results in an overall decrease in heating capacity. The goal of 10 kW heating capacity can be achieved by increasing the compressor size or make use of waste heat from other vehicle components.
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Oliver, Danielle Simonette. "Power Requirements of Control Surface Actuators Towards Active Aeroelastic Control Using the Method of Receptances". Miami University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=miami159601703575348.
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Ummethala, Upendra V. "Control of heat conduction in manufacturing processes : a distributed parameter systems approach". Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/44894.
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Park, Sunho 1976. "Control of oligonucleotide conformation on nanoparticle surfaces for nanoscale heat transfer study". Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/27120.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Includes bibliographical references (leaves 77-82).
Metal nanoparticles can be used as antennae covalently linked to biomolecules. External alternating magnetic field can turn on and off the biological activity of the molecules due to induction heating from the particles that changes the temperature around the molecules. Here an experimental scheme towards direct temperature probing is proposed to predict the behavior of the antenna. Oligonucleotides modified with photosensitive molecules are conjugated with gold nanoparticles and report the temperature at their positions within some nanometers' distance from the particles. However, oligos have a known tendency to stick to gold surfaces. To locate the probes at desired position, 6-mercapto-1-hexanol (MCH) is used to reduce oligonucleotides' adsorption to the surface of gold. The experimental result shows that oligos on particle's surface can be stretched radially without any reduction of coverage ratio. Optimal MCH concentration and reaction time highly depend on the concentration of MCH and the conjugates as well as reaction time and the size of the molecules.
by Sunho Park.
S.M.
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Yebiyo, Metkel. "Optimisation of inter-seasonal ground source heat pumps with predictive behavioural control". Thesis, London South Bank University, 2016. http://researchopen.lsbu.ac.uk/1818/.
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In practice, heat pumps (HP) often do not perform as expected. This is due to many factors such as how well the system and the ground loop are designed, installed and subsequently maintained and how well they are operated and controlled in the field. Improving overall system design and demonstrating increased HP performance and higher reliability are core objectives for this research. Performance instability and variations in ground source heat pump (GSHP) system output has been observed previously and this indicates that detailed research is required for example (i) to identify the relationship between dynamic performance and seasonal ground temperature patterns, (ii) to address the operation, installation and control opportunities that arise from (i). This project investigates all of these issues. This thesis focuses on the monitoring of the long-term operation of a 500 kW installed GSHP system with the aim of understanding and establishing the current trend performance characteristics of the installation. The research involved combination of experimental measurements and analysis, mathematical simulation and the development of an empirical transient model that could be generally applied. Despite the importance of the effect of ground temperatures on performance, relatively little data has been published on the effect of disturbed underground temperature distributions. The author has therefore developed a novel mathematical model for the analysis of disturbed ground temperatures over time. The novel mathematical model developed has been used to predict the disturbed seasonal underground temperatures based on daily fluid and air temperature data and has been validated against real historical data. It was concluded from the critical literature review that the dynamic long term performance investigation of GSHP systems using transient models is not well understood. Therefore the work described in this thesis has focused on the development of a generic empirical transient system model of a GSHP system. This model has been developed using TRNSYS 17 software. This has permitted investigation of the effects of different control strategies using a dry air cooler (DAC) for heat rejection, energy consumption of the HP, the overall performance of the system and ground temperature variations. The main novelty and contributions to science from this work is: The better understanding of the effect of ground temperature variation over time and its effect on the system’s performance. The development of new measurement methods for assessing system performance. The use of ground temperature in the prediction and control of system performance, together with an analysis of the effects of specific interventions or control methodologies. The development of a novel mathematical model for predicting disturbed ground temperature. The development of a novel GSHP model using TRNSYS. The development and investigation of novel control strategies using DAC.
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Surendran, Aswathy. "Passive control of thermoacoustic instabilities in idealised combustion systems using heat exchangers". Thesis, Keele University, 2017. http://eprints.keele.ac.uk/4184/.
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Thermoacoustic instabilities pose a great threat to combustion systems, as they could cause severe structural damage, if they are unchecked and uncontrolled. These instabilities are caused due to the existence of a positive feedback loop between the pressure oscillations and heat release rate oscillations. To prevent these instabilities, one can adopt active or passive control strategies. The aim of the present work is to passively control thermoacoustic instabilities in a domestic boiler system. To this end, the boiler is modelled as a 1D quarter-wave resonator (open at one end and closed at the other) containing a heat source and a heat exchanger (hex). The heat source follows a simple time-lag law for its heat release rate. The hex is modelled as an array of circular tubes in cross flow, and it is placed near the closed end of the resonator, causing it to behave like a cavity-backed tube row. The hex acts as both heat sink and acoustic scatterer. The heat transfer response is obtained from numerical simulations (transfer function approach) and the acoustic scattering or the aeroacoustic response is modelled through a quasi-steady approach. The combination of these two responses at the hex along with the cavity backing gives the effective reflection coefficient of the downstream end of the combustor. Stability maps are constructed for various system parameters. A classical eigenvalue method is used to obtain the complex eigenfrequencies of the first mode of the combustor. From the growth rate (imaginary part of the eigenfrequencies) obtained for different parameter combinations, it is observed that for the eigenfrequency range of interest, an increase in the mean cross flow velocity, in cavity length, or in hex tube diameter, and a decrease in the gap between the hex tubes, all favoured stability.
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Gagnon, Daniel. "Postexercise hemodynamics and control of heat loss responses following exercise-induced hyperthermia". Thesis, University of Ottawa (Canada), 2007. http://hdl.handle.net/10393/27845.
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Purpose. The purpose of this thesis was to investigate the nonthermoregulatory control of cutaneous vascular conductance (CVC) and sweating during recovery from exercise-induced hyperthermia as well as to determine possible sex-related differences during the recovery period. It was hypothesized that an active and passive recovery would maintain mean arterial pressure (MAP), CVC and sweat rate at higher levels than an inactive recovery and result in a faster rate of esophageal temperature (Tes) decay. It was also hypothesized that changes in MAP, CVC and sweat rate would be sex dependent. Methods. Eighteen participants (9 males, 9 females) were rendered hyperthermic by exercise (i.e. Tes = 39.5°C) and recovered in one of three recovery modalities for 60-min: (1) active, (2) inactive or (3) passive. Tes, CVC, sweat rate, cardiac output, stroke volume, heart rate, total peripheral resistance, and MAP were recorded at baseline and 2, 5, 12, 20 and every 10-min until the end of recovery. Results. Both active and passive recoveries were equally effective in maintaining MAP, CVC and sweat rate at greater levels compared with an inactive recovery (p ≤ 0.05). A significantly lower Tes was subsequently observed during passive recovery at 20-min and for the rest of recovery compared to the active mode (p ≤ 0.05). Sex did not affect any of the measured variables at any time point during any recovery mode, with the exception of sweat rate which was significantly higher in males throughout the recovery period (p ≤ 0.05). Conclusion. We conclude that despite an important thermal drive, nonthermal input remains an important influence in the modulation of postexercise heat loss responses. Further, action of the muscle pump/mechanoreceptors is the main nonthermal determinant in the postexercise modulation of MAP, CVC and sweat rate irrespective of sex.
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Park, Sammy Ace. "Combustion instability and active control| Alternative fuels, augmentors, and modeling heat release". Thesis, University of Maryland, College Park, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10129882.
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Experimental and analytical studies were conducted to explore thermo-acoustic coupling during the onset of combustion instability in various air-breathing combustor configurations. These include a laboratory-scale 200-kW dump combustor and a 100-kW augmentor featuring a v-gutter flame holder. They were used to simulate main combustion chambers and afterburners in aero engines, respectively. The three primary themes of this work includes: 1) modeling heat release fluctuations for stability analysis, 2) conducting active combustion control with alternative fuels, and 3) demonstrating practical active control for augmentor instability suppression.
The phenomenon of combustion instabilities remains an unsolved problem in propulsion engines, mainly because of the difficulty in predicting the fluctuating component of heat release without extensive testing. A hybrid model was developed to describe both the temporal and spatial variations in dynamic heat release, using a separation of variables approach that requires only a limited amount of experimental data. The use of sinusoidal basis functions further reduced the amount of data required. When the mean heat release behavior is known, the only experimental data needed for detailed stability analysis is one instantaneous picture of heat release at the peak pressure phase. This model was successfully tested in the dump combustor experiments, reproducing the correct sign of the overall Rayleigh index as well as the remarkably accurate spatial distribution pattern of fluctuating heat release.
Active combustion control was explored for fuel-flexible combustor operation using twelve different jet fuels including bio-synthetic and Fischer-Tropsch types. Analysis done using an actuated spray combustion model revealed that the combustion response times of these fuels were similar. Combined with experimental spray characterizations, this suggested that controller performance should remain effective with various alternative fuels. Active control experiments validated this analysis while demonstrating 50-70\% reduction in the peak spectral amplitude. A new model augmentor was built and tested for combustion dynamics using schlieren and chemiluminescence techniques. Novel active control techniques including pulsed air injection were implemented and the results were compared with the pulsed fuel injection approach. The pulsed injection of secondary air worked just as effectively for suppressing the augmentor instability, setting up the possibility of more efficient actuation strategy.