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1
Millo, Raffaele. "Topological Dynamics in Low-Energy QCD." Doctoral thesis, Università degli studi di Trento, 2011. https://hdl.handle.net/11572/368358.
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In this work we discuss the role of topological degrees of freedom in very low-energy hadronic processes (vacuum polarization and vacuum birefringence). We also present an approach which enables to investigate the microscopic dynamics of non-perturbative processes: this is achieved by constructing an effective statistical theory for topological vacuum gauge configurations, by means of Lattice QCD simulations.
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Millo, Raffaele. "Topological Dynamics in Low-Energy QCD." Doctoral thesis, University of Trento, 2011. http://eprints-phd.biblio.unitn.it/475/1/Tesi_di_Dottorato-_Raffaele_Millo.pdf.
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In this work we discuss the role of topological degrees of freedom in very low-energy hadronic processes (vacuum polarization and vacuum birefringence). We also present an approach which enables to investigate the microscopic dynamics of non-perturbative processes: this is achieved by constructing an effective statistical theory for topological vacuum gauge configurations, by means of Lattice QCD simulations.
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Onus, Cem O. "Continual Energy Management Dynamics| Energy Efficiency in U.S. Automotive Manufacturing Industry." Thesis, Walden University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3630443.
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Managers at automotive manufacturers are seeking ways to reduce energy consumption, costs, carbon emissions, and waste from production processes. Researchers and practitioners perceive energy efficiency as the least expensive and most effective way to deal with issues related to climate change, but adoption of energy efficiency measures has been slow among industrial facilities. The topic of this research study was the decision-making process for energy efficiency projects in the U.S. automotive manufacturing industry. Flaws in this decision-making processes are preventing changes that can dramatically reduce energy usage, cost, and pollution. The study was grounded in the theories of energy management, organizational learning, systems thinking, and strategic management. Data is from open-ended question interviews and questionnaires of 21 decision makers in automotive manufacturing companies in the United States about their perception and experiences regarding the decision-making process for energy efficiency projects. The data were coded to identify themes. The findings indicated that organizational leaders with responsibility over energy management should include energy management standards and frameworks such as ISO 50001, Six Sigma DMAIC, and Energy Star as guidelines for selecting energy efficiency projects. Decision makers may find these results useful in improving their decision-making processes for evaluating energy efficiency projects. This research has the potential to promote positive social change in the automotive industry by reducing energy consumption and business costs, and it could benefit communities by reducing pollution through increasing energy efficiency in the automotive manufacturing industries.
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Onus, Cem O. "Continual Energy Management Dynamics: Energy Efficiency in U.S. Automotive Manufacturing Industry." ScholarWorks, 2011. https://scholarworks.waldenu.edu/dissertations/1144.
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Managers at automotive manufacturers are seeking ways to reduce energy consumption, costs, carbon emissions, and waste from production processes. Researchers and practitioners perceive energy efficiency as the least expensive and most effective way to deal with issues related to climate change, but adoption of energy efficiency measures has been slow among industrial facilities. The topic of this research study was the decision-making process for energy efficiency projects in the U.S. automotive manufacturing industry. Flaws in this decision-making processes are preventing changes that can dramatically reduce energy usage, cost, and pollution. The study was grounded in the theories of energy management, organizational learning, systems thinking, and strategic management. Data is from open-ended question interviews and questionnaires of 21 decision makers in automotive manufacturing companies in the United States about their perception and experiences regarding the decision-making process for energy efficiency projects. The data were coded to identify themes. The findings indicated that organizational leaders with responsibility over energy management should include energy management standards and frameworks such as ISO 50001, Six Sigma DMAIC, and Energy Star as guidelines for selecting energy efficiency projects. Decision makers may find these results useful in improving their decision-making processes for evaluating energy efficiency projects. This research has the potential to promote positive social change in the automotive industry by reducing energy consumption and business costs, and it could benefit communities by reducing pollution through increasing energy efficiency in the automotive manufacturing industries.
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Lasser, Caroline. "Conical energy level crossings in molecular dynamics." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972045333.
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Altinordu, Zeynep. "Transnational Dynamics Of Global Governance In Energy." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612998/index.pdf.
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This thesis aims to provide an analytical outlook for the relevant dynamics of transnational relations in the field of energy with specific reference to key issues and tools for governance. Not only contemporary structure of interdependent and in some cases asymmetrical relations requires a multi-level approach in addressing main issues but also there exists considerable amount of attention in global agenda over alternative policies in response to the developments in this complex context of dynamic and transnational relations whereby an action of an actor results in spillover effects in other regions. It is necessary to have a multi dimensional approach in addressing issues of energy governance where interdependence plays a significant role.
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Van, Schalkwyk Daniel Jacobus. "Dynamics and Energy Management of Electric Vehicles." Thesis, Link to the online version, 2007. http://hdl.handle.net/10019/725.
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Murphy, Gavin Bruce. "Inverse Dynamics based Energy Assessment and Simulation." Thesis, University of Strathclyde, 2012. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=16928.
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The Standard Assessment Procedure (SAP) is the UK Government’s approved methodology for assessing the energy ratings of dwellings. SAP is a calculation method based upon empirical relations from measured data. A yearly calculation was used in SAP until the release of SAP 2009, which employs monthly calculations. SAP has moved from using a large time step with a coarse time resolution to a smaller time step with a medium time resolution. Rising CO2 emissions from dwellings advocate that properties designed in a sustainable method will become commonplace in the future. In tandem with enhanced sustainability, dwellings will increasingly be designed with implementations of renewable energy generation. The modelling of renewables in SAP has been highlighted as an area where SAP could benefit from additional research. Modelling future complex dwellings and systems will require an advanced calculation method which is capable of more detailed modelling and simulation; with a smaller time step which is measured in minutes and not months, producing results allowing more detailed analysis of energy performance. Dynamic Simulation Methods (DSMs) already exist which can operate at a very small time step. However with DSMs it is very difficult to make a comparison with SAP as the temperatures used in SAP are not well understood. To calculate energy consumption the SAP methodology guarantees that a standard occupancy temperature profile is met perfectly. A dynamic method which also guarantees the SAP standard occupancy temperature profile is required. This is difficult in complex DSMs as their control algorithms are often inadequate to optimise the heating system to guarantee that a temperature is met perfectly. The contribution to knowledge detailed in this thesis is the development of a novel SAP compliant advanced dynamic calculation method (IDEAS) v which guarantees that the SAP standard occupancy temperature profile is perfectly tracked and is also calibrated with SAP. The Inverse Dynamics based Energy Assessment and Simulation (IDEAS) method employs the perfect inverse control law RIDE to guarantee that the SAP standard occupancy temperature profile is met. IDEAS produces SAP compliant results and allows confident (i.e. calibrated in SAP) predictions to be made regarding the impact of novel heating and renewable energy systems. Researched in depth are the temperatures used in SAP, leading to analysis of the implications of tracking air temperature and various comfort temperatures. A focused evaluation of the treatment of renewables in SAP and DSMs is also presented, leading to suggestions which were implemented into the SAP framework. The role of real life monitoring in the energy assessment process is highlighted with monitored studies conducted. Also in this thesis case studies applying IDEAS to buildings with renewable heating systems are described. The IDEAS method employs SAP as an exemplar steady state calculation to highlight the successful use and calibration of a new advanced Inverse Dynamics based symbolic method. The philosophy, research and equations derived in IDEAS are presented in this thesis demonstrating their use in Microsoft Excel and Matlab / Simulink environments. The IDEAS methodology is transparent and portable. IDEAS can be applied to other methodologies, such as those employed by PHPP and SBEM (by carrying out a calibration process), and also to different simulation environments such as ESP-r and ESL (by adopting the IDEAS equations in those methods). The contribution to knowledge of IDEAS is demonstrated in this thesis by the development of the method and the use of SAP as a comparator. The IDEAS method has many uses outwith SAP which are highlighted in the cases studies and future work sections of this body of work.
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Marzani, Simone. "High energy resummation in quantum chromo-dynamics." Thesis, University of Edinburgh, 2008. http://hdl.handle.net/1842/3156.
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In this thesis I discuss different aspects of high energy resummation in Quantum Chromo-Dynamics and its relevance for precision physics at hadron colliders. The high energy factorisation theorem is presented and discussed in detail, emphasizing its connections with standard factorisation of collinear singularities. The DGLAP and the BFKL equations are presented and leading twist duality relations between the evolution kernels are discussed. High energy factorisation is used to compute resummed coefficient functions for hadronic processes relevant for LHC phenomenology. The case of heavy flavour production is analysed in some detail and results already present in the literature are confirmed. High energy effects can play an important role for such cross sections which are to be used as standard candles at the LHC, such as W/Z production. To this purpose Drell-Yan processes are studied in high energy factorisation. The inclusive cross section for Higgs boson production via gluon-gluon fusion is analysed both in the heavy top limit and for finite values of the top mass. The different high energy behaviour of the two cases is studied, showing explicitly that the full theory exhibits single high energy logarithms in contrast to the infinite top mass limit. The correct high energy behaviour of the partonic cross section is then combined to the NNLO calculation performed in the heavy top limit, in order to obtain an improved coefficient function. Finite top mass effects at high energy on the hadronic cross section are moderate. As far as parton evolution is concerned, an approximate expression for the NNLO contribution to the kernel of the BFKL equation is computed exploiting running coupling duality relations between DGLAP and BFKL. This result includes all collinear and anticollinear singular contributions and it is computed in various factorisation schemes. The collinear approximation is tested against the known LO and NLO kernels with the discrepancy being at the percent level. Therefore the approximate NNLO contribution is likely to be close to the as yet unknown complete result in the region relevant at leading twist.
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de, Souza V. K. "Glassy dynamics and the potential energy landscape." Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.598458.
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The research within this thesis focuses on the behaviour of glass-forming systems as they are cooled towards the glass transition. In particular, the origins of fragile behaviour are examined. The study of glasses and supercooled liquids involves careful consideration of issues such as equilibrium, ergodicity and metastability. Simulations of the binary Lennard-Jones model glass former explore the diagnosis of broken ergodicity using an energy fluctuation metric and this approach is used to consider ergodic and short-time nonergodic behaviour of the diffusion constant. An underlying Arrhenius temperature dependence of the diffusion constant can be extracted from fragile, super-Arrhenius diffusion. This Arrhenius diffusion can be related to the true super-Arrhenius behaviour by a correction factor that depends on the average angle between atomic displacements in successive time intervals. This correction factor accounts for the fact that on average successive displacements are negatively correlated. This negative correlation can be linked directly with the higher apparent activation energy for diffusion in fragile glass formers at lower temperature. Using information from the potential energy surface, the process of an atom exiting its cage of nearest neighbours, a cage-break, can be explored. The assignment of such an event as a fundamental step for diffusive behaviour can be justified by accurate calculations of diffusion constants. Negative correlation is seen in the direct reversals of a large proportion of the cage-breaking events. Productive cage-breaks, i.e. cage-breaks that are not reversed, can provide a definition of superstructures (megabasins or metabasins) in the energy landscape.
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Carr, J. M. "Energy landscapes and dynamics of model proteins." Thesis, University of Cambridge, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.597302.
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The ‘protein folding problem’ is widely studied, from both an experimental and a computational standpoint. The scale of the resources devoted to this area of research reflects the importance of improving our currently incomplete understanding of how a protein can fold to a well-defined structure under physiological conditions. In the work presented in this thesis, we relate the properties of a protein to its underlying potential energy surface. Using computational methods, we focus on the most important features of the surface: the local minima and the transition states that connect them. Low-energy minima are located using global optimization approaches. Paths through configuration space are characterized in terms of connected sequences of minima and the intervening transition states. The ensemble of such paths between two groups of minima is explored using the discrete path sampling approach. Equilibrium properties are then calculated within the harmonic superposition approximation, and statistical rate theory is used to provide rate constants for transitions between directly connected minima. The folded structures of four small helical proteins are predicted using global optimization algorithms, on the basis of the hypothesis that the folded state is the most favoured thermodynamically. The performance of an approach that incorporates non-sequence-specific information from protein structural databases is compared to that of an existing, unbiased scheme. We then employ the discrete path sampling method to investigate the folding or the villin headpiece subdomain: a 36-residue protein fragment whose behaviour is thought to be characteristic of full proteins. This system offers a significant challenge to existing schemes for exploring and visualizing potential energy surfaces. An improved algorithm for constructing connected paths between local minima is presented and applied. The folding time is calculated using a number of approaches, and the order of folding events is determined using kinetic Monte Carlo simulations.
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Evans, D. A. "Energy landscapes and dynamics of model peptides." Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.598883.
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Understanding how and why a protein folds to a well defined structure would be a great scientific advance. The work in this thesis aims to sample relevant pathways through configuration space to understand how a polypeptide chain can order itself in a short time. The work presented characterises a molecule using its potential energy surface. We construct databases of local minima and the transition states that connect them, and show that these methods are useful in the investigation of larger and more varied peptides than previously studied. New methods for coarse-graining the databases and for plotting free energy disconnectivity graphs are presented. The recently developed discrete path sampling method is applied to biomolecular systems for the first time, and used to iteratively refine stationary point databases by linking groups of minima. The harmonic superposition approximation is used to calculate equilibrium properties, and master equation and kinetic Monte Carlo techniques are employed to calculate kinetic properties. We also implement an internal coordinate optimisation algorithm, and demonstrate it to be more efficient than using Cartesian coordinates by a factor that increases with system size. We apply a selection of these techniques to a range of systems of increasing size. We study the isomerisations of a small dipeptide NATMA with two different force fields, to model experimental ‘quantum yields’ after IR excitation in a jet expansion. We investigate the effects of varying the cooling rate and the excitation energy. Work on the alanine tetra-peptide examines the overall energy landscape and the relative population of a-helical and b structures. The BLN model protein is shown to have numerous low free energy funnels, and the folding transition into the lowest energy state is characterised. The free energy landscape of met-enkephalin is also characterised, and the folding behaviour is examined.
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Dyner, Isaac. "System dynamics platforms for integrated energy analysis." Thesis, London Business School (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275115.
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Miller, Mark Andrew. "Energy landscapes and dynamics of model clusters." Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624347.
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Li, Qian. "Myocyte calcium dynamics and intracellular energy depletion /." The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487588939089482.
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Lumentut, Mikail F. "Mathematical dynamics of electromechanical piezoelectric energy harvesters." Thesis, Curtin University, 2011. http://hdl.handle.net/20.500.11937/1352.
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This research investigates vibration energy harvesting by modelling several piezoelectric-based structures. The usage of piezoelectric transduction under input vibration environments can be profitable for obtaining electrical energy for powering smart wireless sensor devices for health condition monitoring of rotating machines, structures and defence communication technology. The piezoelectric transduction shows strong prospect in the application of power harvesting because it can be applied at the microelectromechanical system design level in compact configuration with high sensitivity with respect to low input mechanical vibration. In this research work, the important aspects of the continuum thermopiezoelectric system associated with the laws of thermodynamics, Maxwell relations and Legendre transformations have been developed to explore the macroscopic thermopiezoelectric potential equations, the thermopiezoelectric equations of state and energy function forms. The application of the continuum thermopiezoelectric behaviour can be used to further formulate novel analytical methods of the electromechanical cantilevered piezoelectric bimorph beams with the tip mass using the weak and strong forms resulting from Hamiltonian’s principle.The constitutive electromechanical dynamic equations of the piezoelectric bimorph beam under one or two input base excitations can be used to derive the equations of the coupled electromechanical dynamic response of transverse-longitudinal form (CEDRTL), the coupled electromechanical dynamic response of longitudinal form (CEDRL) and the coupled electromechanical dynamic response of transverse form (CEDRT). The derivation of the constitutive electromechanical dynamic equations using the weak form of Hamiltonian’s principle can be further derived using the Ritz method associated with orthonomality whereas the closed form or distributed parameter reduced from strong form of Hamiltonian’s principle, can be further formulated using the convergent eigenfunction series with orthonormality. Laplace transformation can be used to give the solution in terms of the multi-mode transfer functions and multi-mode frequency response functions of dynamic displacement, velocity, electric voltage, current, power and optimal power. Moreover, the broadband multi-electromechanical bimorph beam with multi-resonance can also be explored showing the single- and multi-mode transfer functions and frequency response functions. A parametric case study of the piezoelectric bimorph beam with the tip mass and transverse input excitation is discussed to validate the weak and closed forms of the CEDRTL, under series and parallel connections, using the multi-mode frequency response functions with variable load resistance.A further case study of a broadband multi-electromechanical piezoelectric bimorph beam is also discussed using the weak form of the CEDRT to give the frequency response functions under variable load resistance. Finally, the piezoelectric bimorph beams with and without tip masses under transverse base input excitation are also comprehensively discussed using the weak forms of the CEDRTL and CEDRT models and compared with experimental results for variable load resistance. A piezoelectric bimorph beam with tip mass is investigated to show the close agreement between the CEDRTL model and experimental results using the polar amplitudes from the combined action of simultaneous longitudinal and transverse base input excitation.
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Nielsen, Anders. "Gas-phase redox dynamics in high-energy collisions." Thesis, University of Nottingham, 2009. http://eprints.nottingham.ac.uk/10973/.
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Mass analysed ion kinetic energy (MIKE) spectra following collisions have been recorded using a double focusing mass spectrometer with 5 kV acceleration voltage. Metal complexes studied were formed by pick-up of metal atoms in mixed argon/solvent clusters made by supersonic expansion. DFT calculations were used to rationalise experimental data. Complexes of the form MLn+ where M = Mg, Ca, Mn, Cu, and Zn while L = NH3, CO2, benzene, pyridine, acetonitrile, and acetone have been collided with O2 and MgLn+ also with CO2, N2O, acetonitrile, and benzene. Complexes with few ligands are the most prone to oxidation due to their high speed which facilitates electron transfer. Calculated electron affinities, Mulliken populations, and natural bond orbitals of collision gases were used to rationalise electron transfer trends. Collision gases trap electrons more efficiently if they have π-bonds or adjacent electronegative atoms. Metal complex and molecular dications were collided with H2 and O2 to determine the stability of their reduced products. No systematic differences were found between collisions with the two gases at the collision energies examined. The fate of monocations formed in collision depends on their relaxation energy and the dissociation energy of relaxed monocations. LZ theory was unable to explain MIKE spectra. Metal complexes MLn+ and MLn2+ were collided with O2 to determine the propensity to form MXLn-m+ where M = Mg, Ca, Mn, Cu, and Zn while L = CH3X with X = F and Cl. Reactivity is determined by the IE of MLn+ which decrease with increasing n. Dications due to their high dissociation energy are much more likely to react as they can have enough internal energy to overcome potential barriers.
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West, Matthew John. "Energy Budget and Dynamics of the Coronal Reconnection." Thesis, Imperial College London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.498912.
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Sauter, Raphael. "EU energy policy : agenda dynamics and policy change." Thesis, University of Sussex, 2010. http://sro.sussex.ac.uk/id/eprint/2529/.
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This thesis analyses EU energy policy from a comparative agenda-setting perspective providing new theoretical and empirical insights into EU energy policy-making. Although two of the founding treaties of the European Communities covered the coal and nuclear sectors, the European Union has struggled ever since to establish itself in the field of energy policy. In particular, it failed to include an explicit Community competence on energy in Community primary law in subsequent treaty revisions – with the exception of the new Title XX on Energy introduced with the Lisbon Treaty. Nonetheless the European Union has established itself as an important player in European energy policy, as reflected in EU directives on energy market liberalisation, energy efficiency standards and targets for renewable energy sources. At the same time, policymakers at various levels, business, NGOs and experts agree that more EU energy policy is needed to face current and future transnational policy challenges, notably, climate change and energy security. This has led to numerous studies with policy recommendations on EU level action in the field of energy policy. By contrast, very few studies have analysed the drivers and barriers of EU energy policy-making and factors that can explain policy change and stability. Yet a better understanding of EU energy policy-making is a necessary precondition for the development of appropriate policy recommendations. This thesis provides an analysis of EU energy policy-making by identifying factors that can explain change and stability from an agenda-setting perspective. Drawing upon EU studies and agenda-setting literature the analysis distinguishes between two different agenda-setting routes, high and low politics, along the key stages of an issue career: initiation, specification, expansion and entrance. It accounts for the following key variables in EU agenda-setting: contextual factors, policy entrepreneurs, issue definition, and institutional venues. These are applied to two contrasting case studies of EU energy policy: nuclear energy and renewable energy. The study shows how and why Community initiatives failed in an institutionally ‘strong' EU energy policy arena under Euratom, but succeeded in the field of renewable energy under the EC Treaty.
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Chiu, Ya-Tien. "Computational Fluid Dynamics Simulations of Hydraulic Energy Absorber." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/34775.
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Hydraulic energy absorbers may be described as high-loss centrifugal turbomachines arranged to operate as stalled torque converters. The device absorbs the kinetic energy of a vehicle in motion and dissipates the energy into water. A steady, single-phase, Computational Fluid Dynamics (CFD) simulation has been performed to investigate the flow field in a hydraulic energy absorber. It was determined that to better predict the performance of the energy absorber, more sophisticated modeling approaches may be needed.
In this research, a steady, two-phase calculation with basic turbulence modeling was used as a first assessment. The two-phase model was used to investigate cavitation effects. Unsteady and advanced turbulence modeling techniques were then incorporated into single-phase calculations. The Multiple Reference Frame (MRF) Technique was used to model the interaction between the rotor and the stator. The calculations provided clearer details of the flow field without dramatically increasing the computational cost.
It was found that unsteady modeling was necessary to correctly capture the close coupling between the rotor and the stator. The predicted torque in the unsteady calculations was 70% of the experimental value and twice of the result in the steady-state calculations. It was found that the inaccuracy of torque prediction was due to (1) high pressures in the regions with complicated geometrical boundaries and, (2) dynamic interactions between the rotor and the stator were not captured fully. It was also determined that the unrealistically low pressure values were not caused by the physical cavitation, but by the lack of proper boundary conditions for the model. Further integration of the modeling techniques studied would improve the CFD results for use in the design of the energy absorber.Master of Science
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Hlozek, Renée. "Challenges in the hunt for dark energy dynamics." Master's thesis, University of Cape Town, 2008. http://hdl.handle.net/11427/19021.
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Includes bibliographical references. .One of the greatest challenges in modern cosmology is determining the origin of the observed acceleration of the Universe. The 'dark energy' believed to supply the negative pressure responsible for this cosmic acceleration remains elusive despite over a decade of investigation. Hunting for deviation from the 'vanilla' cosmological model, ACDM, and detecting dynamics with redshift in the equation of state remains a key research area, with many challenges. We introduce some of the challenges in the search for such dark energy dynamics. We illustrate that under the assumption of well-motivated scaling models for dark energy dynamics early universe constraints on the dark energy density imply that these models will be essentially indistinguishable from ACDM for the next decade. After introducing the Fisher Matrix formalism, we derive the Fisher Flex test as a measure of whether the assumption of Gaussianity in the likelihood is incorrect for parameter estimation. This formalism is general for any cosmological survey. Lastly, we study the degeneracies between dark energy and curvature and matter in a non-parametric approach, and show that incorrectly assuming values of cosmological components can exactly mimic dark energy dynamics. We connect to the parametric approach by showing how these uncertainties also degrade constraints on the dark energy parameters in an assumed functional form for w. Improving the accuracy of surveys and experiments to search for possible signatures of dark energy dynamics is the focus of much attention in contemporary cosmology; we highlight challenges in the hunt for dark energy dynamics.
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Mikosch, Jochen. "Dynamics of anion-molecule reactions at low energy." [S.l. : s.n.], 2007. http://nbn-resolving.de/urn:nbn:de:bsz:25-opus-42129.
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Voth, Gregory A. Marcus R. A. "Theoretical studies of intramolecular dynamics and energy redistribution /." Diss., Pasadena, Calif. : California Institute of Technology, 1987. http://resolver.caltech.edu/CaltechETD:etd-11292006-135710.
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Setiadi, Jeffry. "Free Energy Molecular Dynamics Simulations of Glutamate Transporters." Thesis, The University of Sydney, 2019. http://hdl.handle.net/2123/20932.
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Molecular dynamics (MD) is a powerful computational tool that paves the way to understand the dynamics and function of life at the molecular level. MD coupled with advanced free energy calculations, and in-silico methods can reveal the underlying mechanism of a physical process that cannot be probed with experimental techniques. The primary investigation in this thesis is to use MD with free energy calculations to explain and elucidate the protein-ligand interactions in glutamate transporters. Glutamate is the major excitatory neurotransmitter in the nervous system and understanding such mechanism may reveal the causes of many pathological conditions linked to glutamate transporters. Here, this thesis presents the results three anomalies observed previously from both experimental and computational studies. First, the instability of a sodium ion bound to the Na2 site observed in simulations is caused by the undercharging of the sulphur atom of the methionine residue in the NMDGT motif. Second, the binding of aspartate to GltPh requires two sodium ions bound in an intermediate state rather than the observed sites revealed from crystallography. Third, the escape of the last sodium ion in the inward-facing conformation shows structural changes in the protein in agreement with experimental observations. An estimate of the escape time from the Na3 site to the bulk indicates this as a slow process in GltPh but is not the rate-limiting step in the transport cycle. As secondary projects, the K+ permeation in gramicidin A (gA) embedded in different lipid membranes and ion solvation in a water droplet is investigated. The potential of mean force (PMF) profile reveals a larger barrier for gA embedded in POPC than in NODS lipid membranes due to the stronger dipole moment of the phosphorus atom. Finally, using spherical boundary condition (SBC) without a buffer zone in the liquid-vacuum interface can give the correct ion-solvation free energy provided a larger system is used.
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Celi, Luciano. "Modeling and communicating the dynamics of energy market." Doctoral thesis, University of Trento, 2019. http://eprints-phd.biblio.unitn.it/3704/1/copertina_tesi.pdf.
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The focus of my Ph.D. project is the investigation of the analogies between the dynamics of oil production, the economy and the physical laws that are related to every natural process. The difficulty to retrieve data on the oil market has suggested me that there is a correspondence in Science Communication: indeed, while in the magazines we find many articles that talk about climate change, for instance, we seldom met articles on related topics with keywords such as "energy resources" or "energy depletion".
I started to investigate the relationship between the phase-plot of worldwide oil production (1965-2014) and its price. My idea was that the laws regulating the convective intensity and the oil production on one side, and the energy flow in human society on the other, were similar. In particular, this analogy could be true for the change from a slow diffusion process to a faster convective movement.
In a first approximation, I tried to describe the phase-plot system in a theoretical way: I imagined the system without perturbations with a worldwide average EROI that varies from 60 (1965) to 15 (2014). Similarly, I picked up the value of world production in 1965 (1,567 Million ton/years) and the same value in 2014 (4,220 Million ton/years) and I assumed a constant increment of the production. Obviously, the phase-plot de-scribes the evolution of the real system and appropriately shows two evident "loops" in correspondence of the two major oil crises in recent times (in the '70s of the last century and in the '10s of the current century), although it is also apparent a "background" (or floor) price the system has never overcome.
Following the idea of a possible description of the global oil market trend as a dynamical system, I investi-gated the eventual analogies between oil market and a classical dynamical system which is well known to exhibit an almost doubly cyclic behavior, i.e., the Lorentz attractor.
However, this suggestion remained nothing better than that, because the major criticism is that it is rather difficult to conceive that only two loops in a phase-plot could be assimilated tout court to a Lorenz attractor: the investigated period 1965-2014 is in fact too short to validate such an analogy. Therefore, the output of the research was an article deposited it in the arXiv online repository .
The relationship between natural phenomena and price-production dynamics of oil extraction, however, could be seen from another point of view. Indeed, the phase-plot, behind the "random walk" initially de-scribed as a Lorenz attractor, suggested us two peaks in correspondence with the upper part of those loops. This "swinging" (macro)behavior is rather similar to that of the theoretical model where we only have two stocks of oil and two prices for them: the first delimited by a price of 100 $/barrel, for a production that re-mains between 0 and 1,000 barrels/day; the second with a cost of 200 $ for a production in the range 1,000-1,500 barrels/day. In this ideal case, following the consumption, we expect the same swinging behavior: if the consumption is in the range between 0 and 1,000 barrels/day, the oil at the lower price will be only used, with a price (ideally) of 100 $/barrel. Since consumption generally grows, the economic system reach-es a point in which it needs to use the second stock of oil at the higher price. As the oil is a global commodi-ty, the price of all oil is determined by the marginal oil barrel, that is to say by the most expensive one (200$). In this ideal dynamics, the price suddenly jumps to the higher level instead of slowly shifting up. If the oil price increases, however, the consumption decreases and, sooner or later, the society comes back to the previous range of extraction intensity. The main characteristic of the simple oil-price dynamics here de-scribed is that there are two rapid movements on the cycle (rise and descent of the price) and two slow movements (consumption that goes up and down, to adapt to the oil price). At this level could be useful in terms of EROI instead of oil stocks (with high and low prices). Therefore, natural variables seem to be more similar to medium price and medium EROI (fast the former, slow the latter).
The Lotka-Volterra equations describe the prey-predator ecological mechanisms and many cases are well known and well-studied. One of them seems to have the same features of the simple oil market behavior just described. More specifically, the analogy is between a prey, the American spruce, and a predator, the caterpillars of the species Choristoneura fumiferana that feed on the spruce. The caterpillar population is regarded as the fast variable, since there are periodically observed demographic outbreaks of this species, considered a real scourge , whereas the spruce leaf whole surface is assumed to be the slow variable be-cause the regeneration of the leaves - and not only - is a process that lasts several decades.
This dynamic model requires a good evaluation of the worldwide EROI for the oil. This is, in any case, fun-damental as an index of the energy quality used by the society. This is the reason why the EROI is crucial to determine the goodness of an energy resource in general and particularly for oil and gas, that nowadays sat-isfy about 57% of primary energy demand .
This dimensionless index is generally defined as the ratio between the energy extracted from a given re-source and the energy costs sustained to get that energy. In a following step of my research, I tried to set up an alternative method for the calculation of the EROI of oil companies. The difficulties to retrieve the data by the oil companies is notorious, thus the strategy consisted in using as a proxy of the energy costs, i.e. the available data about the CO2 emissions of the same oil companies, as reported in their own sustainability reports (SRs). International organizations such as IPCC and WBCSD recommend to the involved companies to compile these reports, but they are not mandatory. The second step was to use, as a proxy of the energy ex-tracted, the CO2 emissions estimate obtained by a stoichiometric conversion of the oil production declared by the oil companies.
The resulting estimates of EROI are rather homogeneous and not too different from the values reported in the literature. The method could be suitable for year-by-year comparison of the time evolution of this im-portant energy quality parameter for the individual energy-producing and energy-delivering companies . I defined this parameter as the "corporate's EROI".
In particular, this last work had its main difficulty in finding data to make comparisons between the different oil companies. As mentioned above, this is also reflected in the communication sector. If we look at the fol-lowing diagram, we can discover, for example, the differences between related argument ("climate change") and keywords like "energy resource" or "energy depletion". The graph includes all the terms worldwide for the last year (October 1st, 2017 - October 1st, 2018) . I am personally committed to filling the gap (thanks to my previous background in Science Communication), to sensitize the citizenship to the energy transition problem and last year, at the Bright event (European Researchers’ Night) I have developed a game about the Hubbert oil peak to play with people and explain to them the dynamics of peak and resource depletion.
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MICHELE, SIMONE. "Flap gates in waves: dynamics andwave energy production." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2015. http://hdl.handle.net/2108/202469.
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Zatta, Alessandro <1976>. "Soil organic carbon dynamics under perennial energy crops." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5921/1/Zatta_Alessandro_SOC_dynamics_perennial_energy_crops.pdf.
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The European renewable energy directive 2009/28/EC (E.C. 2009) provides a legislative framework for reducing GHG emissions by 20%, while achieving a 20% share of energy from renewable sources by 2020. Perennial energy crops could significantly contribute to limit GHG emissions through replacing equivalent fossil fuels and by sequestering a considerable amount of carbon into the soil through the large amounts of belowground biomass produced. The objective of this study is to evaluate the effects of land use change that perennial energy crops have on croplands (switchgrass) and marginal grasslands (miscanthus). For that purpose above and belowground biomass, SOC variation and Net Ecosystem Exchange were evaluated after five years of growth. At aboveground level both crops produced high biomass under cropland conditions as well as under marginal soils. At belowground level they also produced large amounts of biomass, but no significant influences on SOC in the upper layer (0-30 cm) were found. This is probably because of the "priming effect" that caused fast carbon substitution. In switchgrass only it was found a significant SOC increase in deeper layers (30-60 cm), while in the whole soil profile (0-60 cm) SOC increased from 42 to 51 ha-1. However, the short experimental periods (for both switchgrass and miscanthus), in which land use change was evaluated, do not permit to determine the real capacity of perennial energy crops to accumulate SOC. In conclusion the large amounts of belowground biomass enhanced the SOC dynamic through the priming effect resulting in increased SOC in cropland but not in marginal grassland.
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Zatta, Alessandro <1976>. "Soil organic carbon dynamics under perennial energy crops." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5921/.
Full textAbstract:
The European renewable energy directive 2009/28/EC (E.C. 2009) provides a legislative framework for reducing GHG emissions by 20%, while achieving a 20% share of energy from renewable sources by 2020. Perennial energy crops could significantly contribute to limit GHG emissions through replacing equivalent fossil fuels and by sequestering a considerable amount of carbon into the soil through the large amounts of belowground biomass produced. The objective of this study is to evaluate the effects of land use change that perennial energy crops have on croplands (switchgrass) and marginal grasslands (miscanthus). For that purpose above and belowground biomass, SOC variation and Net Ecosystem Exchange were evaluated after five years of growth. At aboveground level both crops produced high biomass under cropland conditions as well as under marginal soils. At belowground level they also produced large amounts of biomass, but no significant influences on SOC in the upper layer (0-30 cm) were found. This is probably because of the "priming effect" that caused fast carbon substitution. In switchgrass only it was found a significant SOC increase in deeper layers (30-60 cm), while in the whole soil profile (0-60 cm) SOC increased from 42 to 51 ha-1. However, the short experimental periods (for both switchgrass and miscanthus), in which land use change was evaluated, do not permit to determine the real capacity of perennial energy crops to accumulate SOC. In conclusion the large amounts of belowground biomass enhanced the SOC dynamic through the priming effect resulting in increased SOC in cropland but not in marginal grassland.
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Negrão, Cezar O. R. "Conflation of computational fluid dynamics and building thermal simulation." Thesis, University of Strathclyde, 1995. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21238.
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The present work is a contribution towards the integration of building simulation tools in order to better represent the complexity of the real world. It attempts to overcome certain shortfalls of contemporary simulation applications with respect to indoor air flows. As a result, the evaluation of building energy consumption and indoor air quality is expected to be improved. Advanced fluid flow models (as employed within Building Thermal Simulation - BTS - and Computational Fluid Dynamics - CFD) with different degrees of detail were investigated and their modelling deficiencies identified. The CFD technique which defines the fluid flow on a micro scale was integrated into BTS in which fluid flow is described in a larger scale. The resulting combined approach strengthens the modelling potential of each methodology by overcoming their specific deficiencies. BTS's inability to predict air flow property gradients within a single space was surmounted and the difficult of estimating CFD boundary conditions are now supplied by BTS. The conflation approach is expected to be employed where gradients of indoor air flow properties can be considered crucial to the evaluation of thermal comfort and energy consumption. The BTS environment, ESP-r, was elected to perform the current work and a new CFD program, dfs, was specifically developed for the analysis of three-dimensional, turbulent, transient air flow. Finally, the two approaches were integrated. The integration work focuses on the CFD boundary conditions where the interactions of BTS and CFD take place; these occur at the inside zone surfaces and at the zone openings. Three conflation approaches were devised addressing different degrees of complexity and sophistication. The first one, involving the two types of zone boundaries, corresponds to a simple approach where the BTS and CFD systems exchange information without any direct interaction. The second approach consists of three other schemes to handle the thermal coupling at the internal zone surfaces. The third approach comprises coupling between the nodal network approach as employed by the BTS environment, and the continuity and momentum equations in the CFD technique. A validation methodology consisting of analytical validation, intermodel comparison and empirical validation is described and applied. The technique is shown to be adequate for modelling indoor air flows when compared to existing models. Three situations, covering the different types of air flows encountered within buildings are discussed to demonstrate the combined method's applicability when compared with the nodal network approach. Finally, general conclusions are presented and some possible future work is identified showing that the developed methodology is very promising.
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Siavosh-Haghighi, Ali. "Topics in molecular dynamics." free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p3164542.
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Fell, C. P. "Relative collision velocity dependance of rotational energy transfer." Thesis, University of Sussex, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384720.
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Christie, H. J. "Molecular dynamics simulations in graphite and carbon materials." Thesis, University of Salford, 2014. http://usir.salford.ac.uk/33006/.
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Despite having significant applications in the nuclear industry, there have been virtually no molecular dynamics (MD) simulations of radiation damage in graphite. The difficulties in developing an accurate yet computationally inexpensive description of carbon have limited the number of detailed investigations. Although previous work has reported point defect energies and estimates of threshold displacement energies, very little is known about the cascade behaviour and the evolution of damage at the atomic level. Gaining an understanding of the processes caused by irradiation in graphite is central to extending the life span of the current advanced gas-cooled nuclear reactors in the UK. In addition, this will provide crucial information to aid next-generation nuclear technology such as the high-temperature graphitemoderated reactors, which were recently selected for development in the USA. The Environment Dependent Interaction Potential (EDIP) has been employed along with the Zeigler-Biersack-Littmark potential to model radiation damage in graphite. Statistical sampling of 20 initial directions and over a range of energies has revealed that nuclear graphite behaves in a manner distinct from metals and oxides, with damage primarily in the form of isolated point defects as apposed to connected regions of transient damage. Simulations have given evidence of channelling occurring along the <10¯12> channel which has previously not been observed in graphite simulations. Graphite cascades have exhibited a fractal-like branching structure and binary-collision-type behaviour. Results produced agree with historical defect prediction models. Important quantities such as the range of the primary knock-on atom and the average energy loss per collision have been calculated. Results indicate that graphite cascades are not dependent on the initial cell temperature. EDIP has been further employed to simulate the effects of radiation damage in carbon allotropes. Results reveal how a material’s structure affects the collision cascade and have highlighted the unique radiation response of graphite.
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Hirai, Kazuo. "Time-energy analysis of molecular vibrational spectra /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/8518.
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MacLeod, Allan M. "Measurements of FEL dynamics." Thesis, Abertay University, 1999. https://rke.abertay.ac.uk/en/studentTheses/6a8f24a4-0ee4-4701-80a9-ce92492f69fa.
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The design, implementation and commissioning of a time-resolved electron energy spectrometer system are discussed. Since its installation at the FELIX free-electron laser user facility in Nieuwegein, The Netherlands, the spectrometer system has been in regular use as a diagnostic and investigative tool. The system provides 0.2% energy resolution with 32 channels, and time resolution of 50 ns. The spectrometer is positioned immediately following the undulator so that the gain medium—the relativistic electron beam—can be probed immediately following its interaction with the optical field in the laser cavity. The system permits real-time calculation and graphical display of key beam parameters as well as the archiving of raw data, and has been used to provide insight into the operation of an FEL in the high slippage, short pulse regime. In particular, direct measurement of the extraction efficiency is possible from macropulse to macropulse. A systematic study of efficiency as a function of wavelength and cavity desynchronisation has been undertaken. At low values of cavity desynchronisation the efficiencies measured exceed the conventional 1/2/V estimate by between 50% and 100% and these results are shown to be consistent with the formation of ultrashort optical pulses—approximately of 6 optical cycles in length. An investigation into the way in which the electron beam energy can be swept on a microsecond time scale has made it possible to produce given sweeps in wavelength—of up to 2 %, limited only by the constraints of the electron beam transport system—which have been used by molecular spectroscopists to excite target molecules through an anharmonic ladder of states. Further evidence for the recent observation of superradiance in an FEL oscillator has been provided by an investigation which shows that the efficiency and intracavity power of the radiation scale respectively as the inverse square root and the inverse square of the cavity losses, verifying the superradiant scaling laws predicted by the supermode theory. An important consequence of this observation is that it indicates that shorter and more intense optical pulses may be produced by increasing the bunch charge and reducing optical cavity losses.
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Park, Haesun. "Essays on price dynamics, discovery, and dynamic threshold effects among energy spot markets in North America." Texas A&M University, 2005. http://hdl.handle.net/1969.1/2668.
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Given the role electricity and natural gas sectors play in the North American economy,
an understanding of how markets for these commodities interact is important. This
dissertation independently characterizes the price dynamics of major electricity and
natural gas spot markets in North America by combining directed acyclic graphs with
time series analyses. Furthermore, the dissertation explores a generalization of price
difference bands associated with the law of one price.
Interdependencies among 11 major electricity spot markets are examined in
Chapter II using a vector autoregression model. Results suggest that the relationships
between the markets vary by time. Western markets are separated from the eastern
markets and the Electricity Reliability Council of Texas. At longer time horizons these
separations disappear. Palo Verde is the important spot market in the west for price
discovery. Southwest Power Pool is the dominant market in Eastern Interconnected
System for price discovery.
Interdependencies among eight major natural gas spot markets are investigated
using a vector error correction model and the Greedy Equivalence Search Algorithm in
Chapter III. Findings suggest that the eight price series are tied together through sixlong-run cointegration relationships, supporting the argument that the natural gas market
has developed into a single integrated market in North America since deregulation.
Results indicate that price discovery tends to occur in the excess consuming regions and
move to the excess producing regions. Across North America, the U.S. Midwest region,
represented by the Chicago spot market, is the most important for price discovery. The
Ellisburg-Leidy Hub in Pennsylvania and Malin Hub in Oregon are important for eastern
and western markets.
In Chapter IV, a threshold vector error correction model is applied to the natural
gas markets to examine nonlinearities in adjustments to the law of one price. Results
show that there are nonlinear adjustments to the law of one price in seven pair-wise
markets. Four alternative cases for the law of one price are presented as a theoretical
background. A methodology is developed for finding a threshold cointegration model
that accounts for seasonality in the threshold levels. Results indicate that dynamic
threshold effects vary depending on geographical location and whether the markets are
excess producing or excess consuming markets.
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Boyle, Mark L. "Energy absorption and redistribution dynamics in isolated C60 molecules." [S.l. : s.n.], 2005. http://www.diss.fu-berlin.de/2005/187/index.html.
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Frederiksen, Joorgen Segerlund. "Theoretical studies in high energy physics and atmospheric dynamics /." Title page, introduction and contents only, 1987. http://web4.library.adelaide.edu.au/theses/09SD/09sdf852.pdf.
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Wang, Chao. "A model study of the dynamics of dark energy." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=106572.
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Observational facts indicate that the expansion of the universe is accelerating, rather than decelerating, because 73% of the total energy density of the universe is a "dark energy" with strong negative pressure, ω < −1/3. In this thesis, we introduce a dynamical dark energy model with dilatational symmetry, which contains two scalar fields coupled to gravity. Because of the dilatational symmetry, there is no cosmological constant Λ in the Lagrangian, and, instead, two scalar fields generate the dark energy, evolving slowly in time. At early times, the system is in the slow roll regime, corresponding to Higgs inflation due to the Higgs field. At late times, the dynamical dark energy dominates the universe and eventually behaves just like the cosmological constant, and the universe becomes exponentially expanding with the scale factor a(t) ∝ exp{Ht}. The numerical results from solving the dynamic equations of the system agree well with the observational facts, which indicates that our model gives a good description of the universe. At the end of the thesis, we consider the one-loop corrections to our model, and show that they do not alter the classical results in any significant way.Les observations actuelles de l'expansion de l'univers indiquent une accéleration decette expansion due à 'l'énergie sombre', qui compte pour 73% de la densité d'énergie totalle de l'univers et qui se comporte comme un fluide avec une pression négative, ω < −1/3. Cette thèse présente un modèle dynamique d'énergie sombre invariant sous une symétrie de dilatation comprenant deux champs scalaires couplés à la gravitation. La constante cosmologique n'est pas présente dans ce modèle, de par la symétrie de dilatation; les champs scalaires génèrent une énergie sombre évoluant dans le temps. Dans l'univers primordial, le système se situe dans le régime d'évolution lente correspondant à l'inflation cosmolgique due au champ de Higgs. L'énergie sombre dynamique agit ultérieurement sur l'évolution de l'univers comme une constante cosmologique; le facteur d'échelle de l'univers accroit de manière exponentielle a(t) ∝ eHt. Les simulations numériques concordent très bien avec les observations actuelles. Les perturbations quantiques de premier ordre sont ensuite calculées, et justifient la validité des résultats obtenus de manière classique.
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Xu, Xu. "Nonlinear dynamics of parametric pendulum for wave energy extraction." Thesis, University of Aberdeen, 2005. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=189414.
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A new concept, extracting energy from sea waves by parametric pendulor, has been explored in this project. It is based on the conversion of vertical oscillations to rotational motion by means of a parametrically-excited pendulor, i.e. a pendulum operating in rotational mode. The main advantage of this concept lies in a direct conversion from vertical oscillations to rotations of the pendulum pivot. This thesis, firstly, reviewed a number of well established linear and nonlinear theories of sea waves and Airy’s sea wave model has been used in the modelling of the sea waves and a parametric pendulum excited by sea waves. The third or fifth order Stokes’s models can be potentially implemented in the future studies. The equation of motion obtained for a parametric pendulum excited by sea waves has the same form as for a simple parametrically-excited pendulum. Then, to deepen the fundamental understanding, an extensive theoretical analysis has been conducted on a parametrically-excited pendulum by using both numerical and analytical methods. The numerical investigations focused on the bifurcation scenarios and resonance structures, particularly, for the rotational motions. Analytical analysis of the system has been performed by applying the perturbation techniques. The approximate solutions, resonance boundary and existing boundary of rotations have been obtained with a good correspondence to numerical results. The experimental study has been carried out by exploring oscillations, rotations and chaotic motions of the pendulum.
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Smith, Adam David. "High energy and high intensity probes of chemical dynamics." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/422224/.
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Gas phase dynamics measurements have been performed using a series of techniques aimed at extending the observation window available to conventional probes. The probes used through the thesis are based on high harmonic spectroscopy, multiphoton ionisation probe photoelectron spectroscopy, and extreme ultraviolet photoelectron spectroscopy. For the high harmonic spectroscopy experiments we have developed a new experimental set-up in Southampton so that high harmonic spectroscopy experiments can be performed. The development of the system has included the design, building and commissioning of a flat field spectrometer to provide improved signal detection and a more suitable energy range for detection of high harmonics generated from molecules. The development of the experiment is presented in chapter 3. A pump probe study of the Raman excitation of CCl4 has been performed demonstrating that high harmonic spectroscopy is sensitive to molecular vibrations, this work is presented in chapter 4. Photoelectron spectroscopy experiments have been performed on both ammonia and carbon disulphide, the results are presented in chapters 5 and 6. The ammonia study employs a multi photon ionisation probe. By probing the dynamics via the intermediate E0 Rydberg state we access a different set of vibrational levels in the ion and maintain overlap with the ion state for an extended period of time. Higher lying ion vibrational states have an average excited state lifetime of approximately 200 fs which closely matches the lifetime associated with the non-adiabatic dissociation process while the lower vibrational states have a much longer lifetime of over 300 fs which more closely matches the adiabatic dissociation process. The different trajectories taken by the two competing dissociation pathways at the region of the conical intersection show up different excitation and ionisation propensity allowing us to isolate features related to each process. By probing carbon disulphide with an extreme ultra violet probe all reaction intermediates have been observed through to the multiple dissociation products. This demonstrates the experimental capabilities whilst using a probe beam generated from high harmonics, whilst this adds a level of complexity to the experiment it has provided a complete observation of the dissociation dynamics. Whilst carbon disulphide is a simple molecular system we have demonstrated that there are complex motions in the electronic and nuclear dynamics of this system that have not been previously observed.
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Lindstens, Robin. "Computational fluid dynamics calculations of a spillway’s energy dissipation." Thesis, Uppsala universitet, Institutionen för fysik och astronomi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-417950.
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To make sure that a dam is safe it is important to have good knowledge about the energy dissipation in the spillway. Physical hydraulic model tests are reliable when investigating how the water flow behaves on its way through the spillway. The problem with physical model testing is that it is both expensive and time consuming, therefore computational fluid dynamics, CFD, is a more feasible option. This projects focuses on a spillway located in Sweden that Vattenfall R&D built a physical model of to simulate the water discharge and evaluate the energy dissipation in order to rebuild the actual spillway. The main purpose of this project is to evaluate if the physical hydraulic test results can be reproduced by using CFD, and obtain detailed results about the flow that could not be obtained by physical testing. There are several steps that need to be completed to create a CFD-model. The first step is to create a geometry, then the geometry needs to be meshed. After the meshing the boundary conditions need to be set and the different models, multiphase model and the viscous model, need to be defined. Next step is to set the operating conditions and decide which solution method that will be used. Then the simulation can be run and the results can get extracted. In this project two CFD simulations were performed. The first simulation was to be compared with the physical hydraulic model test results and the second CFD simulation was of the rebuilt spillway. The results proved that the physical model test results could be recreated by using CFD. It also gave a better understanding of how the energy dissipation was in the spillway and indicates that the reconstruction of the actual spillway was successful since the new spillway both had a higher water discharge capacity and better energy dissipation.
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Dinçerler, Cantekin. "Futures risk premia and price dynamics in energy industry." Access restricted to users with UT Austin EID Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3036593.
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Mc, Isaac Florent. "Energy and money in new frameworks for macro-dynamics." Thesis, Paris 1, 2016. http://www.theses.fr/2016PA01E049/document.
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Depuis la stagflation observée consécutivement à la forte hausse du prix du pétrole en 1973 et 1979, les chocs pétroliers sont considérés comme l’une des sources de fluctuations potentiellement les plus importantes aux États-Unis comme dans de nombreux pays industrialisés. De nombreux articles ont étudié le rôle des chocs pétroliers dans la fluctuation des principales variables macroéconomiques à savoir, la croissance, le chômage, l’inflation et les salaires. Cependant, ces travaux n’ont pas encore permis d’aboutir à un consensus. Le débat s’est même intensifié au cours de cette dernière décennie, en raison d’une absence de réaction forte de l’économie réelle pendant la période d’augmentation du prix du pétrole entre 2002 et 2007. En effet, la récession qu’aurait dû engendrer une telle hausse des prix ne fut observée qu’au moment de la crise des subprimes en 2008. Plusieurs hypothèses furent avancées pour expliquer la différence entre les crises des années 1970 et 2000. Blanchard & Gali (2009) et Blanchard & Riggi (2013) évoquent, par exemple, la réduction de la quantité de pétrole utilisée dans la production, la plus grande flexibilité des salaires réels et une meilleure crédibilité de la politique monétaire. Hamilton (2009) et Kilian (2008) suggèrent quant à eux de l’expliquer par l’origine différente des deux chocs pétroliers : un choc d’offre pendant les années 70 et un choc de demande pendant les années 2000. L’objectif original de la thèse était de réexaminer l’impact des chocs pétroliers sur l’économie réelle par le canal de la dette. [...]Le développement de ces travaux entamés dans la thèse pourra aboutir à un cadre alternatif de modélisation décisif pour l’intelligence de la macroéconomie. Il devrait permettre une meilleure compréhension de l’évaluation des relations réciproques entre la sphère financière, la réalité des cycles macroéconomiques réels, l’énergie et le climat dans ce qui est sans aucun doute l’enjeu de notre génération : la transition écologiqueEver since the stagflation that followed the oil price run-ups of 1973 and 1979, oil price shocks have been considered one of the most influential sources of economic fluctuation in the United States and other developed countries. A large body of literature has analyzed oil price shocks as sources of variation for leading macroeconomic variables such as GDP growth, unemployment rate, inflation, and wages. However, scholars have yet to reach a consensus as to the true impact of oil shocks on the macroeconomic environment. Furthermore, the last decade has seen the debate intensify as the results of the relatively (in comparison with the 1970s) muted reaction of the real economy during the 2002-6 oil price run-up. Indeed, the recessionary effect was only observed during the subprime mortgage crisis of 2008-9. Numerous hypotheses have been put forward to explain the difference in impact during the 1970s versus the 2000s. For instance, Blanchard & Gali (2009) and Blanchard & Riggi (2013) evoked the reduction of the quantity of oil used of a unit of production, more flexible real wages, and a better credibility of the monetary policy. Hamilton (2009) and Kilian (2008) pinpointed a difference in the nature of the shock: whereas the oil shocks of the 1970s were driven by supply, that of the 2000s was led by demand. The original aim of this thesis was to reevaluate the impact of the oil shock in the 2000s through the debt channel. First, based on the work of Banchard & Gali, we proposed a new dynamic stochastic general equilibrium model (DSGE), which includes oil as an input of production as well as a consumption good. By relaxing some of the hypotheses of Blanchard & Gali, especially the decoupling of the output elasticity of oil with the cost-share in the production, our work demonstrated that oil is still a fundamental variable of the GDP in the United States. Furthermore, we found that energy efficiency is a key factor that explains the muted macroeconomic impact of an increase in oil prices. A third line of inquiry that may explain the difference between the shocks of the 1970s and the 2000s considers the extra costs implied by a higher price of oil that were absorbed by private debt (which was itself exacerbated by low interest rates set by the Federal Reserve in the 2000s). However, we found that DSGE modeling is unable to replicate the macroeconomic environment that led to the subprime mortgage crisis. In light of these considerations, I reoriented my thesis along the lines of a new angle of research that seeks to represent economic mechanisms differently. Under this new frame-work, private debt is at the core of macroeconomic analysis. It provides an alternative view of the financial crisis that occurred in the 2000s.[...]The conclusions of this thesis demonstrate great potential for providing foundations for new perspectives in macroeconomic modeling. The papers included in the thesis allow, in particular, for a better understanding of situations that most macroeconomic models are not able to cope with, including the over indebtedness crisis. As a result, the framework introduced here may provide an alternative and improved perspective for public policy. Further development of the research presented in this thesis may lead to the improvement of other frameworks in the field of macroeconomics. This would allow for a better understanding of complex interactions between the financial sphere, real business cycles, energy, and climate in what is certainly the biggest challenge of our generation : the ecological shift
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Ramadugu, Sai Kumar. "Carbohydrate-protein interactions: structure, dynamics and free energy calculations." Diss., University of Iowa, 2013. https://ir.uiowa.edu/etd/1731.
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The current thesis presents work on the structure and dynamics of oligosaccharides and polysaccharides as well as the free energetics of carbohydrate-protein interactions. By applying various computational tools such as molecular dynamics simulation, our in-house fast sugar structure prediction software, replica exchange molecular dynamics, homology modeling, umbrella sampling, steered molecular dynamics as well as the thermodynamic integration formalism, we have been able to study the role of water on the surface of homopolysaccharides as well as complex oligosachharides, we have been able to produce a prediction of the bound structure of triantennary oligosaccride on the asialoglycoprotein receptor, we have been able to estimate the free energy of binding of ManΑ1→2Man to the HIV-1 inactivating protein, Cyanovirin-N as well as the relative binding free energies of mutants of Cyanovirin-N to the same ligand.
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Jendrej, Jacek. "On the dynamics of energy-critical focusing wave equations." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLX029/document.
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Cette thèse est consacrée à l’étude du comportement global des solutions de l’équation des ondes énergie-critique. On s’intéresse tout spécialement à la description de la dynamique du système dans l’espace de l’énergie. Nous développons une variante de la méthode d’énergie qui permet de construire des solutions explosives de type II, instables. Ensuite, par une démarche similaire, nous donnons le premier exemple d’une solution radiale de l’équation des ondes énergie-critique qui converge dans l’espace de l’énergie vers une superposition de deux états stationnaires (bulles). En appliquant notre méthode au cas de l’équation des ondes des applications harmoniques (wave map), nous obtenons des solutions de type bulle-antibulle, en toute classe d’équivariance k > 2. Pour l’équation des ondes énergie-critique radiale, nous étudions également le lien entre la vitesse de l’explosion de type II et la limite faible de la solution au moment de l’explosion. Finalement, nous montrons qu’il est impossible qu’une solution radiale converge vers une superposition de deux bulles ayant les signes opposésIn this thesis we study the global behavior of solutions of the energy-criticalfocusing nonlinear wave equation, with a special emphasis on the description of the dynamics in the energy space. We develop a new approach, based on the energy method, to constructing unstable type II blow-up solutions. Next, we give the first example of a radial two-bubble solution of the energy-critical wave equation. By implementing this construction in the case of the equivariant wave map equation, we obtain bubble-antibubble solutions in equivariance classes k > 2. We also study the relationship between the speed of a type II blow-up and the weak limit of the solution at the blow-up time. Finally, we prove that there are no pure radial two-bubbles with opposite signs for the energy-critical wave equation
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Abedini, Amin. "Piezoelectric Energy Harvesting via Frequency Up-conversion Technology." OpenSIUC, 2019. https://opensiuc.lib.siu.edu/dissertations/1716.
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Ambient energy harvesting has attracted significant attention over the last years for applications such as wireless sensors, implantable devices, health monitoring systems, and wearable devices. The methods of vibration-to-electric energy conversion can be included in the following categories: electromagnetic, electrostatic, and piezoelectric. Among various techniques of vibration-based energy harvesting, piezoelectric transduction method has received the most attention due to the large power density of the piezoelectric material and its simple architectures. In contrast to electromagnetic energy harvesting, the output voltage of a piezoelectric energy harvester is high, which can charge a storage component such as a battery. Compared to electrostatic energy harvester, the piezoelectric energy harvester does not require an external voltage supply. Also, piezoelectric harvesters can be manufactured in micro-scale, where they show better performance compared to other energy harvesters, owing to the well-established thick-film and thin-film fabrication techniques. The main drawback of the linear piezoelectric harvesters is that they only retrieve energy efficiently when they are excited at their resonance frequencies, which are usually high, while they are less efficient when the excitation frequency is distributed over a broad spectrum or is dominant at low frequencies. High-frequency vibrations can be found in machinery and vehicles could be used as the energy source but, most of the vibration energy harvesters are targeting at low-frequency vibration sources which are more achievable in the natural environment. One way to overcome this limitation is by using the frequency-up-conversion technology via impacts, where the source of the impacts can be one or two stoppers or more massive beams. The impact makes the piezoelectric beam oscillate in its resonance frequency and brings nonlinear behavior into the system.
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Fitzgerald, Shaun David. "Fluid dynamics and phase change in geothermal reservoirs." Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309335.
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Ray, Matthew Preston. "The dynamics of energy and charge transfer in low and hyperthermal energy ion-solid interactions." Connect to this title online, 2009. http://etd.lib.clemson.edu/documents/1252424536/.
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Saxena, Chaitanya. "Ultrafast dynamics of energy and electron transfer in DNA-photolyase." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1171317950.
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Menzel, Andreas. "Step dynamics measurements with time-resolved low energy electron diffraction." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/27870.
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