Дисертації з теми "Experimental validations"
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1
van, Deventer Jan. "An ultrasonic density measurement technique : performance, thermal effects, experimental validations, and modeling." Licentiate thesis, Luleå tekniska universitet, EISLAB, 1999. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-18220.
Повний текст джерелаАнотація:
This licentiate thesis addresses the idea of measurement of the density of liquids using sound. The thesis can be dived into three sections: 1. An introduction that presents the need for the research and its future application into an ultrasonic mass flow meter. 2. Experimental results of an ultrasonic density probe (paper 1 and 2) which evaluate the probe's concept with liquids ranging from 750 to 1300 kg/m over temperatures extending form 0 to 40°C. Thermodynamic measurements are also presented. 3. Comparisons of experimental versus theoretically based simulation of ultrasonic systems (paper 3). The theory allows the simulation tool to predict sound generation, propagation and reception as a function of frequency and temperature. Within the thesis are three papers: 1. An Ultrasonic Density Probe. (published in IEEE Ultrasonic symposium) 2. Thermostatic and dynamic performance of a Density Probe. (submitted to IEEE Transactions on UFFC) 3. PSpice simulation of Ultrasonic Systems. (submitted to IEEE Transactions on UFFC)Godkänd; 1999; 20070403 (ysko)
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Rimondi, Federica. "Filter cake washing – Experimental model validation." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
Знайти повний текст джерелаАнотація:
Filter cake washing is an important operation in many process industries, although is widely treated as a “black box” where optimization is performed through trial and error. Mathematical models could predict the performance of the washing process.
In this work three different models are taken into consideration: dispersion model, adsorption model and permeability distribution model.
Experiments were carried out on a Talcum suspension varying the pressure difference of the washing stage.
To validate the models, the results of a single stage wash experiments in a filtration test unit are compared to mathematical simulations.
The results indicate that the dispersion model is not able to mimic the experimental data. The adsorption model predicts in a good way the wash curve, while the loading curve no. The permeability distribution model is able to fit the experimental data and it gives also information about the percentage of the cake that does not participate to the washing stage.
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Peterson, Dale Lukas. "Bicycle dynamics| modelling and experimental validation." Thesis, University of California, Davis, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3602188.
Повний текст джерелаАнотація:
This dissertation explores bicycle dynamics through an extension of the Whipple bicycle model and validation of the model equations equations of motion through the implementation of a robotic bicycle. An extended Whipple bicycle model is presented which makes uses of a unique set of physical parameters based on cylindrical gyrostats. The nonlinear equations of motion for this model are derived, linearized, and validated against a set of benchmark model parameters. A general formulation for the linearization of a system with configuration and velocity constraints is presented, and is demonstrated on an idealized rolling disk. The method of linearization is directly applicable to the equations of motion which result from the application of Kane's method. The linearization procedure is used to formulate the linear state space equations of motion for the bicycle model, which are then used as the plant model to design the robotic bicycle control system. The mechanical, electrical, and software aspects of the robotic bicycle are presented, along with representative results from a set of experiments.
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Raja, Vidya. "Shale Shaker Model and Experimental Validation." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1343768902.
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Sever, Ibrahim Ata. "Experimental validation of turbomachinery blade vibration predictions." Thesis, Imperial College London, 2004. http://hdl.handle.net/10044/1/8393.
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Maranhão, César Miguel Ramos. "FEM analysis in machining and experimental validation." Master's thesis, Universidade de Aveiro, 2008. http://hdl.handle.net/10773/2460.
Повний текст джерелаАнотація:
Mestrado em Engenharia MecânicaA presente investigação contempla a simulação numérica e validação experimental de processos de maquinagem. O estudo consiste na simulação numérica da maquinagem de materiais de alto desempenho como a liga de alumínio 7075 e o aço inox AISI 316 com validação experimental. Diversas simulações e validações foram conduzidas de modo a cobrir uma gama de parâmetros de maquinagem. Forças de corte e de avanço, potência de maquinagem, máxima temperatura de corte e deformação plástica foram validadas com sucesso. Finalmente, foram modeladas outras grandezas nomeadamente tensões residuais no aço inoxidável. ABSTRACT: The present investigation contemplates numerical simulation and experimental validation of machining processes. The study consists in simulating the machining of high performance materials like aluminium alloy 7075 and stainless steel AISI 316 with experimental validation. Several simulations and validations were conducted in order to cover a wide range of machining parameters. Cutting and feed forces, cutting power, maximum cutting temperature and plastic strain were validated with success. Finally, residual stresses in stainless steel were also modelled.
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Atanasova, Nina A. "Animal Models and the Unity of Neuroscience." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406820028.
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Njoya, Motapon Souleman. "A generic fuel cell model and experimental validation." Mémoire, École de technologie supérieure, 2008. http://espace.etsmtl.ca/620/1/NJOYA_MOTAPON_Souleman.pdf.
Повний текст джерелаАнотація:
Les piles a combustibles font partie des sources d'energie renouvelables offrant une energie
electrique propre, silencicuse et avcc un rendement eleve. Elles prennent en entree
I'hydrogenc et fair et les convertissent en energie electrique a travers des reactions
electrochimiques. Cette conversion ne genere que de I'eau et la chaleur.
Les problemes environnementaux crees par la croissance en emissions des gaz a effet de
serre ont augmente I'utilisation de ces piles dans les domaines tels que: les transports, les
portables et la generation de I'energie electrique.
Ces piles produisent une tension electrique qui varie dc fafon non lineaire avec le courant et
elles sont le plus souvent connectees avec d'autres systemes electriques a travers des j
convertisseurs CC-CC. Dans la conception et la simulation des ces convertisseurs ou meme I
de tout le systeme electrique, un modele precis de ces piles est necessaire. Plusieurs articles i
concernant la modelisation des piles a combustibles ont ete publics dans les annees ;
anterieures, mais la majorite des modeles presentes sont obtenus de fa9on empirique ou a j
travers des experiences sur des vraies piles. Ces modeles sont seulement valides pour une ,'
pile en particulier et ne peuvent etre generalises. Cela rend difficile la conception et la
simulation des systemes electriques bases sur les piles a combustible, surtout lorsque
I'utilisateur ne dispose pas d'une vraie pile.
Dans ce projet, une nouvelle approche de modelisation est proposee, une approche ou le
modele de pile est obtenu a I'aide des donnees des fiches techniques des manufacturiers et
qui sont disponibles aux usagers. Le model est generique et capable de representer ie
comportement de n'importe quel type de pile alimentee par I'hydrogene et fair.
Le modele est valide par des comparaisons avec les donnees des fiches techniques et avec
les resultats des tests sur une vraie pile. Une fiche technique d'une pile de 6kW-45V a
membrane echangeuse de protons (PEMFC) de NedStack est consideree pour I'etude et les
experiences sont performees sur une pile de 500W-48V (EPAC-500). Les resultats de
simulation sont tres proches des resultats attendus avec juste une erreur (entre la tension
donnee par le modele et la tension reelle) qui varie entre ± 1 % , ceci tant en regime
permanent qu'en regime transitoire et a n'importe quelle condition d'operation. Ce resuhat est
valide si I'humidite a I'interieur de la pile est bien controlee. Cependant le modele produit une
erreur de 1% lorsque la pression d'air augmente de 9% et une erreur d'environs 3% lorsque la
temperature decroit de 15% sous I'effet de I'humidite.
Le modele propose est integre dans SimPowerSystems (SPS) et rendu disponible pour les
usagers du SPS. Un modele de demonstration d'un vehicule electrique base sur une pile a
combustible est presente pour faire ressortir les avantages du modele propose dans la
simulation des systemes electriques bases sur les piles a combustibles et pour aussi montrer
comment la pile interagit avec d'autres elements electriques. Ce vehicule est modelise avec
les memes caracteristiques que le nouveau vehicule developpe par Honda (la FCX-Clarity-
2008). Les performances du modele de pile et du vehicule sont similaires a la realite en
termes de consommation en hydrogene, vitesse maximale et acceleration. Ce qui confirme la
validite du modele du vehicule.
Le modele du vehicule est une application claire des piles a combustible et peut etre utilise
comme un point de depart dans la conception et la simulation des systemes electriques bases
sur les piles a combustibles.
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Gretton-Watson, Simon Paul. "Hyperbranched PMMA : synthesis, modelling, experimental validation and rheology." Thesis, Imperial College London, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.429144.
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Mohd, Ihsan A. K. A. "Powder compaction, finite element modelling and experimental validation." Thesis, Swansea University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638216.
Повний текст джерелаАнотація:
In the modelling of powder compaction, the behaviour of powders is assumed to be rate-independent elastoplastic, and the process may be described by a large displacement based finite element formulation. Three constitutive relationships to describe the mechanical behaviour of the powders were examined, namely a Mohr-Coulomb yield surface, an elliptical cap yield surface and a combined yield surface model. Of all the models tested, an elliptical cap was shown to be the most appropriate for the compaction phase. An incremental elastoplastic material model was used to simulate the relaxation phase and a plasticity theory for friction was employed in the treatment of the powder-tooling interface for the ejection phase. The model was extended to provide a decoupled thermal solution where the plastic and friction work during the compaction process was considered as sources of energy and the consequent temperature fields were calculated. In parallel, a series of experimental studies were carried out in the laboratory and factory for a plain bush and multi-level component. The parameters which were measured were force, displacement and density. The friction coefficient was derived from the plain bush compaction and shear yield tests were conducted to establish the shear behaviour of the powders. The powders tested are typical of those used in industrial applications. The results detailed information concerning the behaviour of the powders in terms of their material parameters for modelling and in validation of the numerical simulation work. Finally the numerical simulation results were validated against the experimental data to gain confidence in the model developed. The comparisons showed good agreement. The versatility of the simulation allows the complete representation of the green compact generation cycle.
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Sanfedino, Francesco. "Experimental validation of a high accuracy pointing system." Thesis, Toulouse, ISAE, 2019. http://www.theses.fr/2019ESAE0009/document.
Повний текст джерелаАнотація:
Dans la quasi-totalité des missions d'observation de la Terre requérant une grande précision de pointage, les micro-vibrations sont le principal élément dégradant les performances de pointage. Les principales sources de micro-perturbations sont les roues et, lorsqu'il y en a, les refroidisseurs cryogéniques. D’autres sources de perturbations sont les propulseurs chimiques, les moteurs pas à pas de l'antenne solaire, les mécanismes d'entraînement,… L'objectif de cette thèse (NPI) est de concevoir et de valider un système de pointage actif de haute précision à base d’actionneurs piézoélectriques capable de rejeter les micro-vibrations au niveau d’un miroir, avec des pénalités de masse et de puissance contrôlées. Les caractéristiques attendues de ce système sont : • une grande bande passante en boucle fermée : typiquement jusqu'à 100 Hz • une faible erreur résiduelle: typiquement inférieure à 50-100 rad (ordre de grandeur approximatif) • un encombrement et une masse faibles (à quantifier au cours de la thèse) • une puissance requise minimale (à optimiser au cours de la thèse) • la modularité • une possible évolution Ce sujet est fortement pluridisciplinaire (mécanique, automatique, optique et instrumentation). Les défis scientifiques de la thèse sont : • la conception d’un système de pointage actif à bande passante élevée avec impact de masse et de volume faible et une puissance requise à minimiser • la commande robuste du système de pointage actif permettant de rejeter des micro-perturbations dont le spectre varie en fonction des phases de la mission • la tenue des performances en précision • la définition d'une méthodologie générique de conception intégrée applicable à d'autres systèmes de pointage (plusieurs degrés de liberté, ...)On almost all high accuracy pointing Science and Earth observation missions, micro-vibrations are the major contributor to pointing performances degradations (RPE). The main sources of micro-disturbances being the wheels and, when present, the cry-coolers. Other disturbance sources may originate from chemical thrusters, antenna stepper motors, Solar Array Drive Mechanisms (SADM), antenna trimming mechanisms, or payload mechanisms set either inside the sensitive payload, or inside another payload of the same spacecraft. The objective of this NPI is to investigate and validate a high accuracy active pointing system able to reject micro-vibrations at instrument level: • large control bandwidth : typically up to 100Hz • low residual error : typically lower than 50-100nrad (rough order magnitude to be further defined in the frame of this NPI) • low mass and volume impacts • scalable • modular This subject is strongly multidisciplinary (mechanics, control theory, optics and instrumentation). The scientific challenges of the thesis are: • the design of an active pointing system with high bandwidth, low impact of mass and volume and minimized power • the robust control of the active pointing system allowing to reject micro-disturbances whose spectrum varies according to the phases of the mission • obtaining high accuracy performances • the definition of a generic methodology of integrated design applicable to other pointing systems (several degrees of freedom e.g.)
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Owen, Charles Blake. "Two Dimensional Friction Stir Welding Model with Experimental Validation." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1200.pdf.
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Camara, Enrique. "Validation of Time Domain Flutter PredictionTool with Experimental Results." Thesis, KTH, Kraft- och värmeteknologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-160541.
Повний текст джерелаАнотація:
In turbomachinery applications as propulsion and power generation, there is a continuous endeavour to design engines with higher efficiency, driving the compressor and turbine blades towards slimmer and more aerodynamically loaded configurations that frequently operate with fluids at higher temperatures and speeds. This combination of reduced design space and adverse operating environment makes the blades more susceptible to flutter and challenges the designer to predict its occurrence. Nowadays there are different CFD solvers that allow the prediction of flutter in turbomachinery; some of them are more efficient than others and provide considerable computational power savings when compared with traditional CFD methods that sometimes require the simulation of several or all the blades in a given row. The present thesis work is aimed at investigating the strengths and potential limitations of a novel time marching method for Flutter prediction in the Travelling Wave Mode (TWM) domain available in ANSYS CFX 14.5. The results are compared with experimental measurements obtained at the KTH test rig and CFD simulations in the Influence Coefficient Domain (INFC) performed in a previous MSc. Thesis in 2013. An approach in CFX to solve flutter is the Fourier Transformation method that uses only two passages with phase lagged periodic boundary conditions. In the previous thesis only one operating point was calculated using this method. This project focuses on the extension of the calculations to various operating points and expanding the solver validation.Thesis work done at Siemens Industrial Turbomachinery, Finspang, Sweden.
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Potgieter, Brendon Ryan. "Experimental modal analysis and model validation of antenna structures." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5423.
Повний текст джерелаАнотація:
Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: Numerical design optimisation is a powerful tool that can be used by engi- neers during any stage of the design process. Structural design optimisation is a specialised usage of numerical design optimisation that has been adapted to cater speci cally for structural design problems. A speci c application of structural design optimisation that will be discussed in the following report is experimental data matching. Data obtained from tests on a physical structure will be matched with data from a numerical model of that same structure. The data of interest will be the dynamic characteristics of an antenna structure, focusing on the mode shapes and modal frequencies. The structure used was a scaled, simpli ed model of the Karoo Array Telescope-7 (KAT-7) antenna structure. Experimental data matching is traditionally a di cult and time-consuming task. This report illustrates how optimisation can assist an engineer in the process of correlating a nite element model with vibration test data.
AFRIKAANSE OPSOMMING: Numeriese ontwerp-optimisering is 'n kragtige ingenieurshulpmiddel wat ty- dens enige stadium in die ontwerpsproses ingespan kan word. Strukturele ontwerp-optimisering is 'n gespesialiseerde gebruik van numeriese ontwerp- optimisering wat aangepas is om spesi ek van diens te wees by die oplos van strukturele ontwerpsprobleme. 'n Spesi eke toepassing van strukturele ontwerp-optimisering wat in hierdie verslag bespreek sal word, is eksperi- mentele datakorrelasie. Data afkomstig van toetse op 'n siese struktuur sal gekorreleer word met data afkomstig van 'n numeriese model van die selfde struktuur. Die data van belang is die dinamiese eienskappe van 'n anten- nastruktuur, spesi ek die modusvorme en modale frekwensies. Die betrokke struktuur wat gebruik is, is 'n vereenvoudigde skaalmodel van die Karoo Array Telescope-7 (KAT-7) antennastruktuur. Eksperimentele datakorrelasie is, tradisioneel gesproke, 'n moeilike en tydro- wende taak. Hierdie verslag sal illustreer op watter wyse optimisering 'n inge- nieur van hulp kan wees in die proses om 'n eindige elementmodel met vibrasietoetsdata te korreleer.
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Osmak, Fran. "Experimental Validation of Innovative High-Speed Craft Spray Deflectors." Thesis, KTH, Marina system, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-276477.
Повний текст джерелаАнотація:
Hydrodynamic analysis of high-speed craft is a complex problem. For years naval architects have tried improving the eÿciency of the hull, changing its form, the number of hulls, adding spray rails or steps. Spray deflectors, an innovative modification of commonly used spray rails by a Swedish company called Petestep, might be the next advancement in that process. Experimental validation of this concept is the topic of this study. Previous years of towing tank tests showed compelling results, but were unable to draw definite conclusions, mainly due to inability to compare the results of bare hull and deflector hull tests which was a result of unequal trim achieved for equal input parameters (such as weight and speed).With amended test speed range and deflector design modifications, this project aimed to yield unambigu-ous results. Three spray deflectors were designed for di˙erent design speeds, tested and compared with bare hull tests for drag and trim. The results showed that deflectors did not change the running position of the hull compared to bare hull, allowing for an unequivocal drag comparison. Deflectors reduced drag by up to 4.9%.A number of design improvements were proposed as next steps in this research. A further successful proof of concept (increased stability, lower resistance and fuel consumption) could provide a substantial improvement in high-speed craft design resulting in a cheaper and a more comfortable ride with a lower environmental impact.
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Stiebritz, Martin Tillmann. "Development and experimental validation of a protein design software." kostenfrei, 2008. http://www.opus.ub.uni-erlangen.de/opus/volltexte/2008/1060/.
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Fournet, Gabrielle. "IVIM : modeling, experimental validation and application to animal models." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS367/document.
Повний текст джерелаАнотація:
Cette thèse porte sur l’étude de la séquence d’imagerie IRM IVIM (« Intravoxel incoherent motion »). Cette séquence permet l’étude des microvaisseaux sanguins tels que les capillaires, artérioles et veinules. Pour être sensible seulement aux groupes de spins non statiques dans les tissus, des gradients de diffusion sont ajoutés avant et après l’impulsion 180° d’une séquence d’écho de spin. La composante du signal correspondant aux spins qui diffusent dans le tissu peut être séparée de celle des spins en mouvement dans les vaisseaux sanguins qui est appelée signal IVIM. Ces deux composantes sont pondérées par f IVIM qui représente la fraction volumique du sang à l’intérieur du tissu. Le signal IVIM est en général modélisé par une fonction mono-exponentielle (ME) caractérisée par un coefficient de pseudo-diffusion D*. Nous proposons un modèle IVIM bi-exponentiel formé d’une composante lente caractérisée F slow et D* slow qui correspondrait aux capillaires comme dans le modèle ME, et d’une composante rapide caractérisée par F fast et D* fast qui correspondrait à des vaisseaux plus gros comme des artérioles et veinules. Ce modèle a été validé expérimentalement et des informations supplémentaires ont été obtenues en comparant les signaux expérimentaux avec un dictionnaire de signaux IVIM simulés numériquement. L’influence de la séquence d’impulsions, du temps de répétition et du temps d’encodage de diffusion a également été étudiée. Enfin, la séquence IVIM a été appliquée à l’étude d’un modèle animal de la maladie d’AlzheimerThis PhD thesis is centered on the study of the IVIM (“Intravoxel Incoherent Motion”) MRI sequence. This sequence allows for the study of the blood microvasculature such as the capillaries, arterioles and venules. To be sensitive only to moving groups of spins, diffusion gradients are added before and after the 180° pulse of a spin echo (SE) sequence. The signal component corresponding to spins diffusing in the tissue can be separated from the one related to spins travelling in the blood vessels which is called the IVIM signal. These two components are weighted by f IVIM which represents the volume fraction of blood inside the tissue. The IVIM signal is usually modelled by a mono-exponential (ME) function and characterized by a pseudo-diffusion coefficient, D*. We propose instead a bi-exponential IVIM model consisting of a slow pool, characterized by F slow and D* slow corresponding to the capillaries as in the ME model, and a fast pool, characterized by F fast and D* fast, related to larger vessels such as medium-size arterioles and venules. This model was validated experimentally and more information was retrieved by comparing the experimental signals to a dictionary of simulated IVIM signals. The influence of the pulse sequence, the repetition time and the diffusion encoding time was also studied. Finally, the IVIM sequence was applied to the study of an animal model of Alzheimer’s disease
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Smith, Timothy Brian. "Validation of the mine impact burial model using experimental data." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2000. http://handle.dtic.mil/100.2/ADA384951.
Повний текст джерелаАнотація:
Thesis (M.S. in Meteorology and Physical Oceanography) Naval Postgraduate School, Sept. 2000.Thesis advisor(s): Chu, Peter C. Includes bibliographical references (p. 153-154). Also available online.
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Matta, Johnny. "Biomass Fast Pyrolysis Fluidized Bed Reactor: Modelling and Experimental Validation." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/35516.
Повний текст джерелаАнотація:
Of the many thermochemical conversion pathways for utilizing biomass as a renewable energy source, fast pyrolysis is a promising method for converting and upgrading carbonaceous feedstocks into a range of liquid fuels for use in heat, electricity and transportation applications. Experimental trials have been carried out to assess the impact of operational parameters on process yields. However, dealing with larger-scale experimental systems comes at the expense of lengthy and resource-intensive experiments. Luckily, the advances in computing technology and numerical algorithm solvers have allowed reactor modelling to be an attractive opportunity for reactor design, optimization and experimental data interpretation in a cost-effective fashion. In this work, a fluidized bed reactor model for biomass fast pyrolysis was developed and applied to the Bell’s Corners Complex (BCC) fluidized bed fast pyrolysis unit located at NRCan CanmetENERGY (Ottawa, Canada) for testing and validation. The model was programmed using the Microsoft Visual Basic for Applications software with the motivation of facilitating use and accessibility as well as minimizing runtime and input requirements. The application of different biomass devolatilization schemes within the model was conducted, not only for biomass fast pyrolysis product quantity but also liquid product composition (quality), to examine the effect of variable reaction kinetic sub-models on product yields. The model predictions were in good agreement with the results generated from the experimental work and mechanism modifications were proposed which further increased the accuracy of model predictions. Successively, the formulation of the modelled fluid dynamic scheme was adapted to study the effect of variable hydrodynamic sub-models on product yields for which no significant effect was observed. The work also looked into effect of the dominant process variables such as feedstock composition, bed temperature, fluidizing velocity and feedstock size on measurable product outputs (bio-oil, gas and biochar) and compared the results to those generated from the experimental fast pyrolysis unit. The ideal parameters for maximizing bio-oil yield have been determined to be those which: minimize the content of lignin and inorganic minerals in the feedstock, maintain the dense-bed temperature in a temperature range of 450-520 ºC, maximize the fluidization velocity without leading to bed entrainment, and limit the feedstock particle size to a maximum of 2000 μm.
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Leclair, Robert J. "X-ray scatter imaging in medicine, model and experimental validation." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0017/NQ57615.pdf.
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Fowler, William Mark. "Experimental validation of the inverse structural filter force estimation technique." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/17264.
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Sanga, Essau C. M. "Microwave assisted drying of composite materials : modelling and experimental validation." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=38271.
Повний текст джерелаАнотація:
Model materials with discretely varying loss factors under microwave fields, were studied with respect to drying characteristics. In the first part numerical simulations were conducted to study the fluid flow and heat transfer in a rectangular microwave cavity where cylindrical samples were heated by microwave. The Reynolds numbers studied in this work were 2800, 5600 and 11200 based on the entrance diameter to the rectangular microwave cavity. Heat transfer results in terms of Nusselt numbers for the Reynolds number ranges studied are presented and discussed.In the second part of the study a mathematical model was developed to describe heat and mass transfer of a model material under microwave fields. The dynamic temperature and moisture profiles of cylindrical composite samples subjected to microwave and convective energy were determined and validated at microwave power density levels of 0.20 W/g, 0.3 W/g and 0.4 W/g based on initial weight of the sample. Model results were compared with experimental data and found to agree within 1.0--2.6%. Predicted temperature profiles at selected locations within the model material were also showed a good agreement with experimental data. However, a significant discrepancy between the numerical and experimental temperature results occurred after t > 30 minutes. This might have been due to localized overheating, or to mathematical model overestimation.
Lastly, a quality evaluation of the dried samples was also performed. Quality attributes evaluated were surface color, shrinkage and rehydration capacity. Samples dried as a special case of biological material were of better quality when compared to other samples.
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Vujičić, Mile R. "Finite element modelling and experimental validation in radiative heat transfer." Thesis, Swansea University, 2006. https://cronfa.swan.ac.uk/Record/cronfa42640.
Повний текст джерелаАнотація:
The work presented in this thesis can be divided into two parts: numerical modelling and experimental validation. The first part considers a finite element computer code called Pharo which has been developed to simulates heat transfer exchanged in an enclosure via thermal radiation and conduction. This finite element heat transfer code has been written for the Defence, Science and Technology Laboratory (DSTL). Face to face (zonal) thermal radiation which operates with diffuse surface properties of materials without a participating media is analyzed and included in Pharo. To analyze the net heat exchanged within an enclosure several methods for view factor calculation, such as the Monte Carlo and Hemi-cube methods were included in Pharo. During heat transfer simulations a better accuracy of results has been demonstrated using a new approach called the Multiple Reflection of View Factors 'MRV' method. Transient heat flow is solved using both finite difference and finite element time stepping. Also, an analysis of transient heat flow using different solvers (direct and iterative) to find the most appropriate one was carried out. The second part of the work considers experimental validation of numerical results obtained using Pharo. Special attention was given to the analysis of the relationship between view factors and measured heat transfer. To make the experimental data complete the measurements of surface properties including emissivity, reflectivity for different wavelengths as well as roughness of materials is presented. These experimental results can be used as experimental benchmark data for model users and developers.
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Hewitt, Patrick. "Numerical Modeling of a Ducted Rocket Combustor With Experimental Validation." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/28928.
Повний текст джерелаАнотація:
The present work was conducted with the intent of developing a high-fidelity numerical model of a unique combustion flow problem combining multi-phase fuel injection with substantial momentum and temperature into a highly complex turbulent flow. This important problem is very different from typical and more widely known liquid fuel combustion problems and is found in practice in pulverized coal combustors and ducted rocket ramjets. As the ducted rocket engine cycle is only now finding widespread use, it has received little research attention and was selected as a representative problem for this research. Prior to this work, a method was lacking domestically and internationally to effectively model the ducted rocket engine cycle with confidence.
In the ducted rocket a solid fuel gas generator is used to deliver a fuel-rich multi-phase mixture to the combustion chamber. When a valve is used to vary the fuel generator pressure, and thereby the delivered fuel flowrate, the engine is known as a Variable Flow Ducted Rocket (VFDR). The Aerojet MARC-R282 ramjet engine represents the worlds first VFDR flown, and the first in operational use. Although performance requirements were met, improvements are sought in the understanding of the ramjet combustion process with a future aim of reducing the visible exhaust and correcting uneven combustor heating patterns. For this reason the MARC-R282 combustor was selected as the baseline geometry for the present research, serving to provide a documented baseline case for numerical modeling and also being a good candidate to benefit from an improved understanding of the combustion process.
In order to proceed with the present research, experiments were first carried out to characterize the gas generator particulate exhaust in terms of composition and particle size. Equilibrium thermochemistry was used to supplement these data to develop a gas phase combustion model. The gas phase reactions and resulting particle definition were modeling using the FLUENT Computational Fluid Dynamics (CFD) code for the baseline GQM-163A Supersonic Sea Skimming Missile (SSST) operating conditions. These results were compared to direct-connect ramjet ground tests in order to validate the analysis tool.
Data were developed to understand the gas and solid phase fuel exhaust characteristics at the propellant surface, exiting the gas generator injector, and following secondary combustion with air. Particles were collected and analyzed from the fuel generator exhaust. While exhibiting some variation with time in the firing, they were roughly an average of 20 microns in diameter, in line with prior experience with pulverized coal combustion experiments. A computational model was developed based on coal combustion parameters using FLUENT. However, despite considerable effort, the CFD analysis was not able to predict effective burning of the carbon particles to the degree seen in testing. In addition, using equilibrium thermochemistry as a basis for determining the carbon particle content in the fuel exhaust, the CFD analysis resulted in trends in performance opposite to the test results. These facts led to a hypothesis that there was actually a significant fraction of small particles or much less carbon produced than equilibrium thermochemistry would predict. A parametric analysis was performed replacing the 20 micron soot particles with fine fraction particles, representing a fraction of the predicted equilibrium carbon soot being still in the gas phase as higher molecular weight hydrocarbons, or in the form of sub-micron particles. When almost all particles were replaced with fine fraction particles, the model was able to correctly predict absolute values of combustion efficiency as well as trends for different injector geometries. The presence of particles was apparent from the visible exhaust and collection data, however they were found not to play a significant role in the combustion process for this fuel and engine configuration.
The robustness of the computational model was also evaluated by examining the effects of turbulence model, order of discretization, and grid size. Comparable trends and results were seen for all cases examined.
With the successful development of this modeling tool and an improved understanding of the combustion process, future work is enabled to develop improved combustor flow management and fuel injection schemes to improve existing designs and develop new configurations. This research has served to advance the field of combustion modeling by providing: 1) a solid ducted rocket combustion modeling tool considering solid and gas phase combustion, 2) a correlation between primary combustion theory and particulate exhaust sampling, 3) low length/diameter ratio ducted rocket combustor modeling, and 4) combustor CFD coupled with solid particle tracking and combustion models.Ph. D.
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Smith, Christopher Stephen. "Experimental Validation of a Hot Gas Turbine Particle Deposition Facility." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1269547595.
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Gao, Jianqun. "Scuffing modeling and experimental validation in the mixed lubrication regime /." The Ohio State University, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488195154360396.
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Estejab, Ali. "Mathematical and Molecular Modeling of Ammonia Electrolysis with Experimental Validation." Ohio University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1514834805432007.
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Nattinger, Kevin T. "Experimental Validation of the Generalized Harvey-Shack Surface Scatter Theory." Wright State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=wright1536246922074747.
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Kunyansky, L., C. P. Ingram, and R. S. Witte. "Rotational magneto-acousto-electric tomography (MAET): theory and experimental validation." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/623625.
Повний текст джерелаАнотація:
We present a novel two-dimensional (2D) MAET scanner, with a rotating object of interest and two fixed pairs of electrodes. Such an acquisition scheme, with our novel reconstruction techniques, recovers the boundaries of the regions of constant conductivity uniformly well, regardless of their orientation. We also present a general image reconstruction algorithm for the 2D MAET in a circular chamber with point-like electrodes immersed into the saline surrounding the object. An alternative linearized reconstruction procedure is developed, suitable for recovering the material interfaces (boundaries) when a non-ideal piezoelectric transducer is used for acoustic excitation. The work of the scanner and the linearized reconstruction algorithm is demonstrated using several phantoms made of high-contrast materials and a biological sample.
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Leclair, Robert J. (Robert Joseph) Carleton University Dissertation Physics. "X-ray scatter imaging in medicine; model and experimental validation." Ottawa, 2000.
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Moss, Scott. "Modelling and experimental validation of the acoustic electric feedthrough technique." Fishermans Bend, Victoria : Defence Science and Technology Organisation, 2008. http://hdl.handle.net/1947/9738.
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Simmons, Amanda Lee 1970. "An experimental validation of resistance monitoring techniques for Arizona whitefly." Thesis, The University of Arizona, 1996. http://hdl.handle.net/10150/292013.
Повний текст джерелаАнотація:
Three resistance monitoring methods, leaf disk, sticky trap, and vial, were tested to evaluate their relative reliability, discriminating ability, convenience, and practicality for monitoring insecticide resistance in Arizona whiteflies. Each method was evaluated against two field populations divergent in susceptibility using a mixture of fenpropathrin + acephate and two single chemicals, endosulfan and fenpropathrin. Correlations of field efficacy and leaf disk bioassays resistance estimates were conducted with the Yuma population and a comparatively resistant Maricopa population. At each location egg, immature, and adult whitefly densities were monitored before and after fenpropathrin + acephate treatments. The three methods had advantages and disadvantages. The leaf disk method had the greatest discriminating ability, the vial method was the most practical, and the sticky trap method was good at discriminating populations that had large differences in susceptibility. The field efficacy trials indicated good concordance between the leaf disk assays results and field performance.
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Tesorero, Melendez Rafael Angel. "Experimental validation for computationally predicted small RNAs of Streptococcus pyogenes." OpenSIUC, 2011. https://opensiuc.lib.siu.edu/theses/769.
Повний текст джерелаАнотація:
The human pathogen Streptococcus pyogenes (Group A Streptococcus or GAS) are a versatile Gram-positive cocci that havw shown complex modes of regulation of its different virulence factors. Discoveries of a few small non-coding RNAs (sRNAs) in S. pyogenes and their influence on the expression of virulence factors revealed an important role of sRNAs on S. pyogenes virulence. The genome-wide analysis of bacterial genomes for the discovery of sRNAs through computational methods has become an effective way to discover new sRNAs. In this study we provided a computational scheme where three different algorithms (RNAz, eQRNA, and sRNAPredict) were combined to increase the probabilities of predicting putative sRNAs within S. pyogenes' intergenic regions (IGR). A total of 46 candidates were chosen based on our criteria, and through Northern blot we analyzed each candidate. We obtained hybridization signals from twelve newly discovered sRNAs in S. pyogenes. Subsequently, we analyzed their sequence and their location within the IGR to find a putative -10 promoter region and possible Rho-independent terminator site, and their possible targets through computational methods. We further expanded our analysis of the new sRNAs by using Real-Time RT-PCR to determine the expression of sRNAs during different phases of growth. Our results showed that our computational scheme and experimental method was effective in predicting sRNAs previously undiscovered in S. pyogenes, and that more sRNAs are yet to be discovered and characterized, helping to further understand the regulation of virulence factors in S. pyogenes
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Olsson, Niklas, and Christian Selberg. "Numerical simulation and experimental validation of a manufactured wing profile." Thesis, Högskolan Väst, Avdelningen för Industriell ekonomi, Elektro- och Maskinteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-14287.
Повний текст джерелаАнотація:
The background for this thesis originates from a study of the flow characteristics for an airfoil of the type NACA0018. The aim for this thesis was to evaluate how the characteristics of the flow over the NACA0018 profile depend on surface roughness. Airfoils were manufactured in Aluminum by Computer Numerical Control-milling and in polylactide polymer using a 3D-printer, where some of the profile surfaces were postprocessed with sandpaper in various grain sizes. The surface roughness of the profiles was evaluated in a 3D optical profilometer using white light interferometry from Filmetrics. By that technique 3D surface plots were created. The manufactured airfoils were tested in a wind tunnel where the achieved data was made dimensionless for comparative purposes. The computational fluid dynamics simulations were performed in Ansys Fluent and compared against the wind tunnel data as well as with the data from a previously made study at htw saar. The results from the wind tunnel tests show that the surface roughness has an effect on the flow characteristic of the airfoil, where different angles of stall were observed in the comparison. The difference for the dimensionless numbers coefficient of lift and drag show that the manufactured aluminum airfoil performs better compared to the 3D-Printed airfoil in this study. It has a higher performance mean value for both of these coefficients in a span of angles between 0 and 30 degrees. When compared, the results from the simulations and wind tunnel experiments do match in some cases, where the dimensionless coefficients and stall angle coheres. Further studies based on this report are recommended, where small geometric changes to the profile could be tested and validated.
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Ellaithy, Amr. "Metabotropic Glutamate Receptor 2 Activation: Computational Predictions and Experimental Validation." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5319.
Повний текст джерелаАнотація:
G protein-coupled receptors (GPCRs) are the largest family of signaling proteins in animals and represent the largest family of druggable targets in the human genome. Therefore, it is of no surprise that the molecular mechanisms of GPCR activation and signal transduction have attracted close attention for the past few decades. Several stabilizing interactions within the GPCR transmembrane (TM) domain helices regulate receptor activation. An example is a salt bridge between 2 highly conserved amino acids at the bottom of TM3 and TM6 that has been characterized for a large number of GPCRs. Through structural modeling and molecular dynamics (MD) simulations, we predicted several electrostatic interactions to be involved in metabotropic glutamate receptor 2 (mGlu2R) activation. To experimentally test these predictions, we employed a charge reversal mutagenesis approach to disrupt predicted receptor electrostatic intramolecular interactions as well as intermolecular interactions between the receptor and G proteins. Using two electrode voltage clamp in Xenopus laevis oocytes expressing mutant receptors and G-proteins, we revealed novel electrostatic interactions, mostly located around intracellular loops 2 and 3 of mGlu2R, that are critical for both receptor and G-protein activation. These studies contribute to elucidating the molecular determinants of mGluRs activation and conformational coupling to G-proteins, and can likely be extended to include other classes of GPCRs.
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Laurent, Sylvain. "Validation experimentale du concept d'etoile laser pour l'optique adaptative." Paris 6, 1996. http://www.theses.fr/1996PA066230.
Повний текст джерелаАнотація:
Dans le domaine de l'imagerie astronomique, l'optique adaptative permet, en theorie, d'acceder a une resolution angulaire uniquement limitee par la diffraction en depit des perturbations introduites par la turbulence atmospherique. L'efficacite de cette technique necessite de disposer d'un objet ou d'une source de reference suffisamment lumineux. L'experience atlas (analyse de la turbulence par laser) developpee a l'onera, a ete concue pour creer une source de reference artificielle par retrodiffusion rayleigh et mie d'un faisceau laser pulse, et analyser simultanement les fronts d'onde de l'etoile artificielle et d'une etoile naturelle proche. Le travail presente fournit les elements theoriques et experimentaux requis pour la validation de ce concept d'etoile artificielle. Il met plus particulierement l'accent sur les sources d'erreur, notamment au niveau de l'analyse de front d'onde, ainsi que sur les phenomenes qui rendent incertaine l'interpretation des mesures. Les premiers resultats experimentaux sont presentes. Ils portent sur la mesure des correlations spatiales entre les fronts d'onde d'une etoile naturelle et d'une etoile laser, en fonction de l'altitude de focalisation et de l'ecart angulaire entre les deux etoiles. Ces resultats sont discutes avec l'appui de simulations numeriques des effets du bruit et d'anisoplanetisme
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Poupinet, Ludovic. "Imagerie laser par synthese d'ouverture : theorie et validation experimentale." Paris 11, 1997. http://www.theses.fr/1997PA112158.
Повний текст джерелаАнотація:
Nous avons etudie theoriquement et experimentalement une technique d'imagerie active par synthese d'ouverture. Une source laser eclaire un objet. Le champ optique retrodiffuse par ce dernier est mesure par un detecteur mobile. La detection heterodyne permet au detecteur de mesurer la phase et l'amplitude du champ. Le deplacement du detecteur permet d'effectuer ces deux mesures en differents points de l'espace. Un algorithme de deconvolution reconstruit ensuite une image de l'objet eclaire. Cet algorithme, en connaissant le support de l'objet, complete les mesures effectuees et reconstitue ainsi le champ optique dans une pupille virtuelle. L'etude theorique de cette methode permet d'en definir les limites de validite (dimensions de l'objet, configuration de mesure), d'etablir les performances que l'on peut attendre (rapport signal a bruit, champ de vision, resolution) et enfin, de mettre l'accent sur les points delicats de la realisation experimentale (precision de deplacement, connaissances a priori de l'objet). Un montage experimentale de validation est defini puis realise. Le deplacement du detecteur est assure, virtuellement, par un periscope de position et d'ecartement variables permettant d'adresser differents points d'un plan. Les variations de chemin optique dans la voie signal doivent etre compensees avant la reconstruction. Le montage experimental est teste avec divers objets. Les resultats obtenus demontrent la validite de la methode et permettent de mettre en avant les points qui peuvent etre ameliores. En conclusion, cette technique d'imagerie permet une grande souplesse dans le traitement des donnees. En effet, les memes mesures peuvent etre utilisees pour reconstruire des images avec differentes focales, pour analyser le front d'onde retrodiffuse, ou determiner la distance separant l'objet du detecteur. Cette souplesse ouvre de larges perspectives d'applications.
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Gerbaux, Luc. "Modélisation d'une pile à combustible de type hydrogène/air et validation expérimentale." Grenoble INPG, 1996. http://www.theses.fr/1996INPG0163.
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Cadafalch, Rabasa Jordi. "Numerical Simulation of Turbulent Flows. Multiblock Techniques. Verification and Experimental Validation." Doctoral thesis, Universitat Politècnica de Catalunya, 2002. http://hdl.handle.net/10803/6681.
Повний текст джерелаАнотація:
Work here presented is the result of basic research in key aspects of the currently available engineering tools and methodologies for the design, optimisation and development of thermal systems and equipment: turbulence modelling, high performance computing and quality tests and procedures so as to assess credibility to the numerical solutions (verification and validation). The thesis comprises six main chapters written in a paper format. Two of them have already been published in international journals, one in the proceedings of a Spanish conference and two in proceedings of international conferences on Computational Fluid Dynamics and heat transfer. The last chapter has recently been submitted for publication to an international journal. Therefore, all the chapters are written so as to be self-contained, complete and concise. As a consequence, some contents of the chapters such those describing the governing equations, or the verification procedure used to assess the credibility of the numerical solutions, are repeated in several of them. Furthermore, as only minor changes have been introduced in the chapters respect to the original papers, each of them reflects the know-how of the CTTC (Heat and Mass Transfer Technological Centre were the research has been carried out) when they were published.
Papers presented in chapters 1 and 2 deal with turbulence modelling. A general overview is given on the formulation and numerical techniques of the different levels of turbulence modelling: Direct Numerical Simulation (DNS), Large Eddy Simulation (LES) and Reynolds Averaged Navier-Stokes Simulation (RANS). Main attention is focussed on the eddy viscosity two-equation RANS models. Their formulation is presented in more detail, and numerical solutions of the most extended. Benchmark problems on turbulence modelling are given compared to the available experimental data.
Chapters 3 and 4 focus on the use of the multiblock method (domain decomposition method), as a numerical technique that combined with the parallel computing may allow reducing the demanding computational time and memory (high performance computing). The multiblock approach used is based on the conservation of all the physical quantities (fully conservative method) and on an explicit information exchange between the different blocks of the domain. The goal of the work presented in these two chapters is to verify that such a multiblock approach does not introduce additional uncertainty in the numerical solutions.
Chapter 5 presents a tool that has been developed at the CTTC for the verification of finite volume computations. In fact, this tool is also partially used and described in the results presented in the previous chapters. Here, it is described and discussed in detail and it is applied to a set of different CFD and heat transfer problems in two and three dimensions, with free and forced convection, with reactive and non-reactive flows and with laminar and turbulent flows.
The last chapter shows a complete study for the development of a credible heat transfer relation for the heat evacuated from a ventilation channel. Such study comprises all the different steps that have to be accomplished so as to develop credible and applicable results in mechanical engineering. It comprises a description of the mathematical model to represent the physical phenomena in the channel, the numerical model to solve the set of coupled differential equations of the mathematical model, the construction and testing of an ad-hoc experimental set-up, and a verification and validation (V&V) test that guarantees that the numerical solution is an accurate enough approximation of the mathematical model (verification), and that it properly predicts the reality (validation).
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Méndez, Diez Joel. "Thermoviscoplasticity of glassy polymers experimental characterization, parameter identification and model validation." Stuttgart Inst. für Mechanik (Bauwesen), 2010. http://d-nb.info/1000784371/34.
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Marzband, Mousa. "Experimental validation of optimal real-time energy management system for microgrids." Doctoral thesis, Universitat Politècnica de Catalunya, 2014. http://hdl.handle.net/10803/145069.
Повний текст джерелаАнотація:
Nowadays, power production, reliability, quality, efficiency and penetration of renewable energy sources are amongst the most important topics in the power systems analysis. The need to obtain optimal power management and economical dispatch are expressed at the same time. The interest in extracting an optimum performance minimizing market clearing price (MCP) for the consumers and provide better utilization of renewable energy sources has been increasing in recent years. Due to necessity of providing energy balance while having the fluctuations in the load demand and non-dispatchable nature of renewable sources, implementing an energy management system (EMS) is of great importance in Microgrids (MG). The appearance of new technologies such as energy storage (ES) has caused increase in the effort to present new and modified optimization methods for power management. Precise prediction of renewable energy sources power generation can only be provided with small anticipation. Hence, for increasing the efficiency of the presented optimization algorithm in large-dimension problems, new methods should be proposed, especially for short-term scheduling. Powerful optimization methods are needed to be applied in such a way to achieve maximum efficiency, enhance the economic dispatch as well as provide the best performance for these systems. Thus, real-time energy management within MG is an important factor for the operators to guarantee optimal and safe operation of the system. The proposed EMS should be able to schedule the MG generation with minimum information shares sent by generation units. To achieve this ability, the present thesis proposes an operational architecture for real time operation (RTO) of a MG operating in both islanding and grid-connected modes. The presented architecture is flexible and could be used for different configurations of MGs in different scenarios. A general formula is also presented to estimate optimum operation strategy, cost optimization plan and the reduction of the consumed electricity combined with applying demand response (DR). The proposed problem is formulated as an optimization problem with nonlinear constraints to minimize the cost related to generation sources and responsive load as well as reducing MCP. Several optimization methods including mixed linear programming, pivot source, imperialist competition, artificial bee colony, particle swarm, ant colony, and gravitational search algorithms are utilized to achieve the specified objectives. The main goal of the thesis is to validate experimentally the design of the real-time energy management system for MGs in both operating modes which is suitable for different size and types of generation resources and storage devices with plug-and-play structure. As a result, this system is capable of adapting itself to changes in the generation and storage assets in real-time, and delivering optimal operation commands to the assets quickly, using a local energy market (LEM) structure based on single side or double side auction. The study is aimed to figure the optimum operation of micro-sources out as well as to decrease the electricity production cost by hourly day-ahead and real time scheduling. Experimental results show the effectiveness of the proposed methods for optimal operation with minimum cost and plug-and-play capability in a MG. Moreover, these algorithms are feasible from computational viewpoints while having many advantages such as reducing the peak consumption, optimal operation and scheduling the generation unit as well as minimizing the electricity generation cost. Furthermore, capabilities such as the system development, reliability and flexibility are also considered in the proposed algorithms. The plug and play capability in real time applications is investigated by using different scenarios.
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Juspi, Sumyaty. "Experimental validation of the shakedown concept for pavement analysis and design." Thesis, University of Nottingham, 2007. http://eprints.nottingham.ac.uk/12864/.
Повний текст джерелаАнотація:
The shakedown concept has been widely applied in structural and mechanical engineering numerical models. The concept is related to the response of a structure to load repetitions in a resilient manner without further permanent deformation. More than 40 wheel tracking tests were conducted with various wheel load levels for each test to check the validity of the shakedown concept in the pavement foundation. Six different types of soils with different characteristics were used in the wheel tracking tests. These were a silt (from gravel pit washings), a silty-clay (Mercia Mudstone, referred to here by its earlier name of Keuper Marl), two sands (Portaway and Langford Fill), and two crushed rocks (Carboniferous Limestone and Granite). Three different sized wheel-tracking facilities were used; a small wheel tracker (SW), a larger Slab Testing Facility (STF) and the half-scale Nottingham Pavement Testing Facility (PTF). These allowed various wheel specifications and test specimen sizes to be investigated. The test programme embraced one, two and three layered systems. The permanent vertical deformation of each system was measured after a certain number of passes. The soil is said to be under shakedown if after a certain number of passes, there is no further permanent deformation. The experimental result was compared with the theoretical shakedown prediction. A series of static triaxial tests for each soil, with the test conditions close to the wheel tracking tests, was carried out to identify the shear strength to be used as input parameters for the theoretical shakedown prediction. The theoretical shakedown limits of the various soil combinations show a good agreement with the wheel tracking test results.
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SalvadoÌ-Estivill, Ignasi. "Photocatalytic oxidation of indoor air pollutants : kinetics, modelling and experimental validation." Thesis, University of Nottingham, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445693.
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Sairi, Maryam. "Prediction and experimental validation of the char yield of crosslinked polybenzoxazines." Thesis, University of Surrey, 2018. http://epubs.surrey.ac.uk/849422/.
Повний текст джерелаАнотація:
This study uses Molecular Operating Environment (MOE) to generate models to calculate the char yield of polybenzoxazines. A series of benzoxazine monomers were constructed to which a variety of parameters relating to the structure (e.g. water accessible surface, negative van der Waals surface area and hydrophobic volume, etc.) were obtained and a quantitative structure property relationships (QSPR) model was generated. The model was used to generate data for a new benzoxazine monomer and a comparison was made of predictions based on the QSPR models with the experimental data. This study shows the quality of predictive models and confirms how useful computational screening is prior to synthesis. In order to do that, the QSPR models were tested over a series of internal and external validation tests to explore their internal and external predictivity, prior to experimental validations which were performed later and reported in Chapter 7. The internal and external validations found out that the discrepancy in the general model (GM) which was initially thought to be a drawback to the model’s performance was actually not, as it does not compromise the model’s prediction accuracy, both internally and externally. The validation process also found that one of the structure-specific models, Ph-M (aniline-based benzoxazines) is externally predictive whilst another structure-specific model, the Ace-M (acetylenic-based polybenzoxazines) is not internally and externally predictive due to the too small training set that affects its predictivity performance. An acetylenic-based polybenzoxazine, poly(BA-apa) and a benzylamine-based polybenzoxazine, poly(BO-ba) have been successfully synthesised in this work. Both materials have been characterised using Fourier Transform – Infra Red Spectroscopy (FT-IR), Nuclear Magnetic Resonance (NMR) spectroscopy (both 1H and 13C) and Liquid Chromatography-Mass Spectrometry (LC-MS) to confirm their structures. These materials were analysed using Differential Scanning Calorimetry (DSC) to study their polymerisation behaviour and were later cured and taken further to Thermogravimetric Analysis (TGA) in order to investigate their thermal properties and the amount of char yield formed upon heating at 800 oC under an inert (nitrogen) atmosphere – which then will be used for experimental validation of the QSPR models. The study of DSC thermograms showed that both polymers exhibit a distinct polymerisation behaviour e.g. BA-apa went through two polymerisation reactions simultaneously (the oxazine ring opening polymerisation and the acetylene addition reaction) whilst BO-ba only polymerised via the ring opening reaction from the oxazine rings. It was also found that BA-apa has a lower polymerisation activation energy, consistent to its lower polymerisation temperature in comparison to the BO-ba. TGA analysis revealed that poly(BO-ba) formed an average of 44.35 % char yield and poly(BA-apa) on the other hand formed approximately 10 % higher char which is 56.28 %. The analysis also discovered that poly(BA-apa) synthesised in this work formed 15 % less char yield than previously reported in the literature (56.28 % vs. 71 %1) due to the shorter curing schedule. The final QSPR validation which is the experimental validation found that the char yield of poly(BO-ba) was predicted very well within 5-7 % error by both GM model and Ph-M. Ace-M which was reported earlier as not internally and externally predictive, has made a nearly accurate prediction towards the char yield of poly(BA-apa), close to the literature value of 71 %. The GM model has also made a close prediction to the Ace-M model, but these predictions deviated 15-17 % from the experimental poly(BA-apa) char yield measured in this work.
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Mallory, Gregory J. W. (Gregory John Wilmshurst) 1971. "Development and experimental validation of direct controller tuning for spaceborne telescopes." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/9173.
Повний текст джерелаАнотація:
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2000.Includes bibliographical references (p. 285-294).
Strict requirements in the performance of future space-based observatories such as the Space Interferometry Mission (SIM) and the Next Generation Space Telescope (NGST), will extend the state-of-the-art of critical mission spaceflight-proven active control design. A control design strategy, which combines the high performance and stability robustness guarantees of modem, robust-control design with the spaceflight heritage of conventional control design, is proposed which will meet the strict requirements and maintain traceability to the successful controllers from predecessor spacecraft. Two principal tools are developed: an analysis algorithm that quantifies each sensor/actuator combination's effectiveness for control, and a design engine which tunes a baseline controller to improve performance and/or stability robustness. The sensor/actuator effectiveness indexing tool requires a reduced-order state-space model of the plant. A modification of the balanced reduction method is introduced which improves numerical conditioning so that the order of large models of flexible spacecraft may be decreased. For each sensor and actuator an index is computed using the modal controllability from an actuator weighted by the modal cost in the performance, and the model observability of a sensor weighted by the modal cost of the disturbance. The special case of actuators that are used for active output isolation is handled separately. The designer makes use of the sensor/actuator indexing tool to select which control channels to emphasize in the tuning. The tuning tool is based on forming an augmented cost from weighting performance, stability robustness, deviation from the baseline controller, and controller gain. The tuning algorithm can operate with the plant's state-space design model or directly with the plant's measured frequency-response data. Two differentiable multivariable stability robustness metrics are formed, one based on the maximum singular value of the Sensitivity transfer matrix and one based on the multivariable Nyquist locus. The controller is parameterized with a general tridiagonal parameterization based on the real-modal state-space form. The augmented cost is chosen to be differentiable and a closed-loop stability-preserving unconstrained nonlinear descent program is used to directly compute controller parameters that decrease the augmented cost. To automate the closed-loop stability determination in the measured-data-based designs, a rule-based algorithm is created to invoke the multivariable Nyquist stability criteria. The use of the tuning technique is placed in context with a high-level control design methodology. The tuning technique is evaluated on a sample problem and then experimentally demonstrated on a laboratory test article with dynamics, sensor suite, and actuator suite all similar to future spaceborne observatories. The developed test article is the first spacetelescope- like experimental facility to combine large-angle slewing with nanometer optical phasing and sub-arcsecond pointing in the presence of spacecraft-like disturbances. The technique is applied to generate an improved controller for a model of the SIM spacecraft.
by Gregory J.W. Mallory.
Ph.D.
46
Chilenski, Mark Alan. "Experimental data analysis techniques for validation of Tokamak impurity transport simulations." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/112393.
Повний текст джерелаАнотація:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2017.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages [234]-309).
This thesis presents two new techniques for analyzing data from impurity transport experiments in magnetically confined plasmas, with specific applications to the Alcator C-Mod tokamak. The objective in developing these new techniques is to improve the quality of the experimental results used to test simulations of turbulent transport: better characterization of the uncertainty in the experimental results will yield a better test of the simulations. Transport codes are highly sensitive to the gradients of the background temperature and density profiles, so the first half of this thesis presents a new approach to fitting tokamak profiles using nonstationary Gaussian process regression. This powerful technique overcomes many of the shortcomings of previous spline-based data smoothing techniques, and can even handle more complicated cases such as line-integrated measurements, computation of second derivatives, and 2d fitting of spatially- and temporally-resolved measurements. The second half of this thesis focuses on experimental measurements of impurity transport coefficients. It is shown that there are considerable shortcomings in existing point estimates of these quantities. Next, a linearized model of impurity transport data is constructed and used to estimate diagnostic requirements for impurity transport measurements. It is found that spatial resolution is more important than temporal resolution. Finally, a fully Bayesian approach to inferring experimental impurity transport coefficient profiles which overcomes the shortcomings of the previous approaches through use of multimodal nested sampling is developed and benchmarked using synthetic data. These tests reveal that uncertainties in the transport coefficient profiles previously attributed to uncertainties in the temperature and density profiles are in fact entirely explained by changes in the spline knot positions. Appendices are provided describing the extensive work done to determine the derivatives of stationary and nonstationary covariance kernels and the open source software developed as part of this thesis work. The techniques developed here will enable more rigorous benchmarking of turbulent transport simulations, with the ultimate goal of developing a predictive capability.
by Mark Alan Chilenski.
Ph. D.
47
Ebrahimi, Mohammadreza. "CFD-DEM modelling of two-phase pneumatic conveying with experimental validation." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/9693.
Повний текст джерелаАнотація:
A wide range of industrial processes involve multiphase granular flows. These include catalytic reactions in fluidized beds, the pneumatic conveying of raw materials and gas-particle separators. Due to the complex nature of multiphase flows and the lack of fundamental understanding of the phenomena in a multiphase system, appropriate design and optimized operation of such systems has remained a challenging field of research. Design of these processes is hampered by difficulties in upscaling pilot scale results, the difficulties involved in experimental measurements and in finding reliable numerical modelling methods. Significant work has been carried out on numerical modelling of multiphase systems but challenges remain, notably computational time, appropriate definition of boundary conditions, relative significance of effects such as lift and turbulence and the availability of reliable model validation. The work presented in this thesis encompasses experimental and numerical investigations of horizontal pneumatic conveying. In the experimental work, carefully controlled experiments were carried out in a 6.5 m long, 0.075 m diameter horizontal conveying line with the aid of the laser Doppler anemometry (LDA). Initially, LDA measurements were performed to measure the gas velocity in clear flow. Good agreement was observed between the theory and experimental measurements. For two-phase experiments, spherical and non-spherical particles with different sizes and densities were used to study the effect of particle size and solid loading ratio on the mean axial particle velocity. Three different sizes of spherical glass beads, ranging from 0.9 mm to 2 mm and cylindrical shaped particle of size 1x1.5 mm were employed. It was found that by increasing the particle size and solid loading ratios, the mean axial particle velocity decreased. Turbulence modulation of the carrier phase due to the presence of spherical particles was also investigated by measuring fluctuating gas velocity for clear gas flow and particle laden flow with different particle sizes and solid loading ratios. Results suggested that for the size ranges of particles tested, the level of gas turbulence intensity increased significantly by adding particles, and the higher the solid loading ratio, the higher the turbulence intensity. With the rapid advancement of computer resources and hardware, it is now possible to perform simulations for multiphase flows. For a fundamental understanding of the underlying phenomena in pneumatic conveying, the coupled Reynolds averaged Navier-Stokes and discrete element method (RANS-DEM) was selected. The aim of the modelling section of this study was to evaluate the abilities of coupled RANSDEM to predict the phenomena occurring in a research-sized pneumatic conveying line. Simulations for both one-way and two-way RANS-DEM coupling were performed using the commercial coupled software FLUENT-EDEM in an Eulerian- Lagrangian framework, where the gas is simulated as a continuum medium, while solid phase is treated as a discrete phase. In one-way coupling simulations, a considerable discrepancy in mean axial particle velocity was observed compared to the experimental results, meaning two-way coupling was required. It was further found that the inclusion of Magnus lift force due to particle rotation was essential to reproduce the general behaviour observed in the experiments. Turbulence modulation also was investigated numerically. Experimental and simulation results of gas and particle velocities were compared showing that the RANS-DEM method is a promising method to simulate pneumatic conveying. However, some discrepancy between simulation and experimental results was observed. Most studies in two-phase flow fields have focused on spherical particles. However the majority of particles encountered in industry involve non-spherical granules which show considerably different transportation behaviour compared with spherical particles. Further modelling of cylindrical particles was conducted using a multisphere model to represent cylindrical particles in the DEM code. Drag and lift forces and torque equations were modified in the code to take the effect of particle orientation into account. The framework developed was evaluated for two test cases, indicating a good agreement with the analytical and experimental results. The transportation of isometric (low-aspect-ratio) non-spherical particles in pneumatic conveying was also modelled. The simulation results of mean axial particle velocity agreed well with the experimental measurements with the LDA technique.
48
Halasz, Christopher. "Advanced Trailing Edge Blowing Concepts for Fan Noise Control: Experimental Validation." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/34040.
Повний текст джерелаАнотація:
This thesis documents trailing edge blowing research performed to reduce rotor / stator interaction noise in turbofan engines. The existing technique of filling every velocity deficit requires a large amount of air and is therefore impractical. The purpose of this research is to investigate new blowing configurations in order to achieve noise reduction with lesser amounts of air. Using the new configurations air is not injected into every fan blade, but is instead varied circumferentially. For example, blowing air may be applied to alternating fan blades. This type of blowing configuration both reduces the amount of air used and changes the spectral shape of the tonal interaction noise. The original tones at the blade passing frequency and its harmonics are reduced and new tones are introduced between them. This change in the tonal spectral shape increases the performance of acoustic liners used in conjunction with trailing edge blowing. This thesis presents numerical predictions performed to estimate the sound power reductions due to these concepts, as well as experimental results taken on the ANCF rig at NASA Glenn for validation purposes. The results show that the new concepts are successful in increasing the efficiency of trailing edge blowing.Master of Science
49
Jorgenson, Dawn Blilie. "Optimizing current delivery in defibrillation : finite element models and experimental validation /." Thesis, Connect to this title online; UW restricted, 1994. http://hdl.handle.net/1773/8054.
Повний текст джерела
50
Retailleau, Alain. "Validation expérimentale d'une méthode de prédiction de l'érosion par cavitation." Université Joseph Fourier (Grenoble), 1995. http://www.theses.fr/1995GRE10050.
Повний текст джерелаАнотація:
Le present travail est consacre au developpement et a la validation experimentale d'une methode de prediction quantitative de l'erosion par cavitation. La demarche de prediction retenue consiste a mesurer le potentiel erosif, ou agressivite, d'un ecoulement cavitant afin de le reproduire de facon acceleree puis d'obtenir une mesure previsionnelle de l'erosion. La definition de l'agressivite repose sur l'analyse statistique des microdeformations plastiques isolees formees a la surface des parois solides elastoplastiques au debut de l'endommagement. Les distributions aleatoires, spatiale et dimensionnelle, de ces indentations sont reduites aux trois grandeurs scalaires: vst le volume total des indentations par unite de surface et par unite de temps, rm et hm la moyenne des distributions, ponderees par le volume, du rayon et de la profondeur des indentations. Quant a l'erosion, elle est mesuree par l'evolution de la profondeur de l'endommagement macroscopique des parois au cours du temps. Des mesures d'agressivite et d'erosion ont ete realisees pour des ecoulements venturis experimentaux de deux echelles geometriques differentes. Pour les conditions de similitude caracterisant ces ecoulements cavitants, les transpositions des mesures d'agressivite et d'erosion, associees a un changement d'echelle geometrique et/ou a un changement de vitesse de l'ecoulement, ont ete verifiees. Par ailleurs, il est montre qu'un parametre adimensionnel, ii, caracteristique de l'interaction liquide/solide permet de transposer les mesures de l'agressivite lors d'un changement de materiau, elastoplastique, de la paroi solide de l'ecoulement. L'observation d'une tres forte correlation entre le taux de deformation volumique vst et la vitesse d'erosion permet d'envisager une nouvelle demarche de prediction de l'erosion. Des mesures d'agressivite et d'erosion ont egalement ete realisees pour les ecoulements du caversim, moyen d'essais defini pour la reproduction acceleree de l'endommagement par cavitation. L'observation de la meme correlation entre la mesure de l'agressivite, vst, et la vitesse d'erosion, pour ces ecoulements cavitants tout a fait differents des ecoulements venturis, permet de valider experimentalement la methode proposee de prediction de l'erosion par cavitation