Dissertations / Theses: 'Energy exchange'

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Khorashad, Arash Sorouri. "Investigation of the exchange energy density functional." Thesis, Imperial College London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504765.

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Density Functional Theory (DFT) is an important tool in the treatment of quantum many-body problems. In spite of being exact in principle, the application of DFT requires the use of approximations, because it involves an unknown universal functional called the exchange-correlation energy. In this thesis we describe an accurate and efficient extension of Chawla and Voth's planewave based algorithm for calculating exchange energies, exchange energy densities, and exchange energy gradients with respect to wave function parameters in systems of electrons subject to periodic boundary conditions. The theory and numerical results show that the computational effort scales almost linearly with the number of plane waves and quadratically with the number of k vectors. To obtain high accuracy with relatively few k vectors, we use an adaptation of Gygi and Baldereschi's method for reducing Brillouin zone integration errors. We then generate a large database of highly accurate exchange energy densities in 106 artificial but realistic solid-state systems. We use the database not only to examine the accuracy of some important existing exchange functionals, but also to show that there exists a smooth function of the local electron density, its gradient and Laplacian that fits our data well. We also study the effects of twist-averaging on the finite-size errors in the exchange energy of a uniform electron gas, using the Ewald, model periodic Coulomb (MPC) and screened Coulomb interactions. In the case of the Ewald interaction, this investigation is carried out in both the canonical (fixed particle number) and grand-canonical (fixed Fermi wave vector) ensembles. Finally, we study the new reciprocal-space approach to the . Coulomb finite-size errors introduced by Chiesa et al. and find that it is almost equivalent to the use of the MPC interaction.

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Kerr, Duncan James Mackay. "Exchange-correlation energy of inhomogeneous electron gases." Thesis, University of Cambridge, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627264.

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Ng, Hui-Siong. "Low energy (K§+, ¹²C) charge exchange cross section measurements." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ60159.pdf.

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Bexell, Jonas, and Erik Bjureus. "A study of energy exchange in earth air tubes." Thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-93600.

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As energy issues today are of great interest the writers of this report have done a research about an alternative to save energy by reducing the cost of preheating the outdoor air. By taking the outdoor air to the ventilation system via a pipe buried in the ground, you can preheat the outdoor air, which, in turn, could save energy. By doing this you do not have to bring as much energy to preheat the supply air, to get the desired supply air temperature. The report also explains if the earth air tubes are a good complement to the mechanical ventilation system with a heat exchanger. The report begins with describing briefly the history of ventilation systems in use today. It also describes the functions of the system and show to the reader how two of the installation layouts looks like. The writers using the project Daggkåpan in Linköping as a basis for the investigation and they also provide an alternative solution to the existing ventilation system. This report also demonstrate the factors that come into play to get as much energy exchange as possible, and what problems may arise with this type of complement to the ventilation system with a heat exchanger. Trough optimization of the earth air tubes and depending on which energy source is in use, you can actually save energy and by that also money. The factor that proved to bethe most significant for the energy exchange was the pipe length. Other factors such as trench depth, pipe diameter and the air flow has been shown to play a smaller role in how much energy you can save. Finally the report ends with the writers own reflections and a discussion based on the results.
Eftersom energifrågor idag är av stort intresse har rapportskrivarna undersökt ett alternativ till att tjäna energi genom att dra ner kostnaderna för uppvärmning av tilluften i ett ventilationssystem. Detta genom att ta tilluften för ett från- och tilluftssystem med värmeväxlare via rör nedgrävda i marken kan man förvärma tilluften, vilket man i sin tur skulle kunna tjäna energi på. Man slipper på så sätt tillföra lika mycket energi för att få den önskade tilluftstemperaturen. Rapporten tar även upp om marklagda ventilationsrör är ett bra komplement till från- och tilluftssystemet. Rapporten börjar med att beskriva kort om ventilationens historia samt olika ventilationssystem som används idag. Vidare beskrivs hur ett system med marklagda rör fungerar och även två layouter på hur systemet kan installeras. Rapportskrivarna använder projektet Daggkåpan i Linköping som grund för undersökningen och de ger även en alternativ lösning till det befintliga ventilationssystemet. I denna rapport påvisas även vilka faktorer som spelar in för att få ett så stort energiutbyte som möjligt samt vilka problem som kan uppstå med denna typ av komplement till ett från- och tilluftssystem. I rapporten ser man hur man genom optimering av marklagda rör samt beroende på vilken elenergikälla man använder sig av, faktiskt kan tjäna energi och i sin tur pengar på att installera markrör. Den faktor som visat sig spelat in mest på hur energiutbytet påverkas är främst längden. Övriga faktorer så som grundläggningsdjup, diameter samt luftflöde har visat sig spela mindre roll på hur mycket energi man kan spara med dessa rör. Slutligen avslutas rapporten med rapportskrivarnas egna reflektioner och en diskussion utifrån resultaten.

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Jalles, Diogo Oom de Sousa Tovar. "Weak-form efficiency of equity energy exchange traded funds." Master's thesis, Instituto Superior de Economia e Gestão, 2012. http://hdl.handle.net/10400.5/10865.

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Mestrado em Finanças
O principal objetivo desta dissertação de final de mestrado é aferir se os Exchange Traded Funds (ETF) Energéticos são eficientes na forma fraca. Para o período compreendido entre 2008 e 2012 selecionámos todos os ETFs energéticos que são negociados no mercado de capitais dos Estados Unidos, com uma data de emissão anterior a 2008. A amostra selecionada é composta por 26 ETFs e foram usados os dados históricos dos preços diários para aplicar vários testes: testes de autocorrelação, testes de runs, testes de raízes unitárias admitindo quebras estruturais, análise de raízes unitárias em painel e testes de rácio de variância. Estes testes permitiram-nos concluir que a variação dos preços dos ETFs Energéticos seguem um passeio aleatório e que a hipótese de eficiência fraca não é rejeitada.
The main purpose of this final master dissertation is to assess the weak-form efficiency of Equity Energy Exchange Traded Funds (ETF). For the period of 2008-2012 we selected all equity energy ETFs traded in the U.S. stock market with inception date before 2008. The sample selected, is composed by 26 ETFs and we make use of full daily historical data and apply various tests: autocorrelation tests, runs test, unit roots structural breaks tests, panel unit roots analysis and variance ratio tests. These tests allow us to conclude that equity energy ETFs price changes follow a random walk, and so the weak-form efficiency hypothesis is not rejected.

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Alam, Muddasser. "Enabling cooperative and negotiated energy exchange in remote communities." Thesis, University of Southampton, 2013. https://eprints.soton.ac.uk/366694/.

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Energy poverty at the household level is defined as the lack of access to electricity and reliance on the traditional use of biomass for cooking, and is a serious hindrance to economic and social development. It is estimated that 1.3 billion people live without access to electricity and almost 2.7 billion people rely on biomass for cooking, a majority of whom live in small communities scattered over vast areas of land (mostly in the Sub-Saharan Africa and the developing Asia). Access to electricity is a serious issue as a number of socio-economic factors, from health to education, rely heavily on electricity. Recent initiatives have sought to provide these remote communities with off-grid renewable microgeneration infrastructure such as solar panels, and electric batteries. At present, these resources (i.e., microgeneration and storage) are operated in isolation for individual home needs, which results in an inefficient and costly use of resources, especially in the case of electric batteries which are expensive and have a limited number of charging cycles. We envision that by connecting homes together in a remote community and enabling energy exchange between them, this microgeneration infrastructure can be used more efficiently. Against this background, in this thesis we investigate the methods and processes through which homes in a remote community can exchange energy. We note that remote communities lack general infrastructure such as power supply systems (e.g., the electricity grid) or communication networks (e.g., the internet), that is taken for granted in urban areas. Taking these challenges into account and using insights from knowledge domains such game theory and multi-agent systems, we present two solutions: (i) a cooperative energy exchange solution and (ii) a negotiated energy exchange solution, in order to enable energy exchange in remote communities. Our cooperative energy exchange solution enables connected homes in a remote community to form a coalition and exchange energy. We show that such coalition a results in two surpluses: (i) reduction in the overall battery usage and (ii) reduction in the energy storage losses. Each agents's contribution to the coalition is calculated by its Shapley value or, by its approximated Shapley value in case of large communities. Using real world data, we empirically evaluate our solution to show that energy exchange: (i) can reduce the need for battery charging (by close to 65%) in a community; compared with when they do not exchange energy, and (ii) can improve the efficient use of energy (by up to 10% under certain conditions) compared with no energy exchange. Our negotiated energy exchange solution enables agents to negotiate directly with each other and reach energy exchange agreements. Negotiation over energy exchange is an interdependent multi-issue type of negotiation that is regarded as very difficult and complex. We present a negotiation protocol, named Energy Exchange Protocol (EEP), which simplifies this negotiation by restricting the offers that agents can make to each other. These restrictions are engineered such that agents, negotiation under the EEP, have a strategy profile in subgame perfect Nash equilibrium. We show that our negotiation protocol is tractable, concurrent, scalable and leads to Pareto-optimal outcomes (within restricted the set of offers) in a decentralised manner. Using real world data, we empirically evaluate our protocol and show that, in this instance, a society of agents can: (i) improve the overall utilities by 14% and (ii) reduce their overall use of the batteries by 37%, compared to when they do not exchange energy.

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Sanchez-Friera, Paula. "Total energy calculations from self-energy models." Thesis, University of York, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369299.

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Hastie, Michele. "Energy and Water Conservation in Biodiesel Purification Processes." Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/20384.

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Biodiesel purification processes generate wastewater streams that require a large amount of energy when distillation is used as a treatment technology. Process simulation software was used to show that an alternative water treatment process involving ion exchange would require only 31% of the energy used by distillation. Experiments showed that multiple washing stages were required to meet the standard specification for sodium, an impurity present in crude biodiesel, when washing biodiesel made from used frying oil. A comparison was made between washing biodiesel in a cross-current washing configuration and a counter-current configuration. Both configurations met the specification for sodium within three washing stages; however, the counter-current configuration required less water, making it the more efficient process. Lastly, the removal of sodium from wastewater samples using an ion exchange resin was experimentally investigated. The results validated the use of ion exchange to reduce energy consumption in biodiesel purification.

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Enberg, Rikard. "Quantum chromodynamics and colour singlet exchange in high energy interactions." Doctoral thesis, Uppsala University, Department of Nuclear and Particle Physics, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3385.

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Quantum chromodynamics (QCD) is the fundamental theory in elementary particle physics that describes the strong interaction in terms of exchanges of force-carrying, colour-charged particles known as gluons. Although well-established through experimental verifications, there are fundamental unsolved problems in the theory.

In this thesis, some novel aspects of strong interaction dynamics are studied in the context of colour singlet exchange processes — interactions where complex systems of gluons with no net colour charge are exchanged. Both perturbative and non-perturbative QCD methods are used, as well as Monte Carlo computer simulations.

Soft colour interactions in the final state of a high energy collision can lead to effective colour singlet exchange. Non-perturbative models for such interactions are shown to give a good description of diffractive production of W, Z, bb, J/ψ and jets in pp collisions at the Tevatron. Predictions are given for diffractive Higgs boson and prompt photon production at hadron colliders.

Rapidity gaps between jets is a new phenomenon which is studied with an improved perturbative calculation of hard colour singlet exchange using the BFKL equation, taking into account previously neglected contributions and non-leading logarithmic corrections. Including also underlying soft rescattering effects, the complete model reproduces well data from the Tevatron.

Diffractive vector meson production through hard colour singlet exchange in γp collisions is studied in the framework of the conformal invariant non-forward solution of the BFKL equation. Expressions for helicity-dependent amplitudes are derived, and the results show good agreement with data on J/ψ and ρ production from the ep collider HERA.

These studies lead to a deeper knowledge of complex gluon dynamics, and therefore advance our understanding of QCD.

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Keane, Michael K. "Hysteresis phenomena of ferromagnetic bodies using the nonlocal exchange energy model." Diss., This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-06062008-171642/.

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Edwards, Eric Alan. "Water, Energy and Carbon Dioxide Exchange of a Riparian Mesquite Woodland." Thesis, The University of Arizona, 2002. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_etd_hy0090_sip1_w.pdf&type=application/pdf.

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Rugmai, Supagorn. "Three-body models of breakup and charge-exchange reactions." Thesis, University of Surrey, 1998. http://epubs.surrey.ac.uk/843216/.

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We formulate and apply a three-body Glauber model and an adiabatic theory, as alternative approaches to the DWBA method, to study breakup and charge exchange reactions of loosely bound nuclei. The theories derive full finite-range transition amplitudes, which incorporate three-body effects. The formulated Glauber three-body breakup transition amplitude is applied to the (d, pn) deuteron breakup reaction. Three-body s-wave breakup calculations are performed to analyse 260 MeV 63Cu(d, pn) and 270 MeV 12C(d, pn) reaction differential cross-section data. The calculations describe the data fairly well, for low p-n relative energies. The adiabatic theory, in a special limit, is applied to enable computational checks of the Glauber three-body breakup calculations, and for estimation of non-s-wave breakup contributions to the (d, pn) reaction. An adiabatic theory of Coulomb breakup is presented which derives a closed-form adiabatic transition amplitude for Coulomb breakup. Calculations describe deuteron breakup at forward angles at 56, 140 and 270 MeV reasonably well. Previous DWBA analyses are also discussed, and assumptions made in those DWBA calculations are discussed critically. The three-body Glauber model is extended to study the (d, pp) charge-exchange reaction. Three-body effects in the 12C(d, pp)12B reaction are investigated by comparing Glauber calculations with their DWBA limits. The results indicate that these three-body effects are significant and might be responsible for ad hoc modifications needed in DWBA analyses of the same reaction.

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Kellner, Erik. "Surface Energy Exchange and Hydrology of a Poor Sphagnum Mire." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2001. http://publications.uu.se/theses/91-554-5121-7/.

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Terway, Timothy M. (Timothy Michael). "Industrial symbiosis and the successional city : adapting exchange networks to energy constraints." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40129.

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Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 2007.
Includes bibliographical references (p. 115-[119]).
Industrial ecology offers models for hybridizing technology and natural processes, human desires and the capacities of ecosystems in an effort to reconcile the expanding conflicts among them. Industrial symbiosis applies this thinking to the scale of the city and its supporting industrial operations. Case studies of industrial symbiosis, which is the changing of linear, open-loop production to closed-loop systems through the reuse and exchange of waste materials, energy, and knowledge, showcase advantages in waste and energy use reduction within the United States. What are the major limits holding back the widespread development of industrial symbiosis in this country and how can they be overcome? Secondly, what tools can foster its large-scale implementation once the constraints are overcome? Methodologically, the successful study of the future capacity of industrial symbiosis within the American context must address the future consequences of resources that are no longer cheap nor abundant, as well as the current state of their production, distribution, and consumption.
(cont.) The major constraints facing industrial symbiosis in America are: current extremely high subsidies in transport and resource costs, low symbiosis visibility, non-existent data collection standards, undeveloped communication networks, and no unified regulatory mechanisms. Future limits and cost changes in transport and resources will become the ultimate push to make exchange habits a widespread practice in the United States, enabling the above issues to be effectively addressed. The timing of these limits is uncertain. Yet, planners must be in the right place at the right time with the proper tools to facilitate a transition to the widespread implementation of industrial symbiosis. This thesis provides a framework for how planners can foster the successful large-scale implementation of industrial symbiosis in the U.S. through a variety of interventions. It suggests four distinct tools: increased visibility of industrial symbiosis through marketing outlets; a new web-based "social-networking" tool for industries to share information and expand communication; a multiple-tiered regulation structure to facilitate standards development; and lastly physical planning that intelligently responds to future trends in energy, resources, mobility, and spatial patterns of industrial development.
by Timothy M. Terway.
M.C.P.

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Loukova, G. V. "Harvesting and Electron-Exchange Energy Transfer by d0 Metallocene-based Organized Systems." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35397.

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The present contribution will provide an up-to-date overview of novel experimental and theoretical (de-rived quantum-chemically) knowledge on photonics of group IV metallocene-based systems, also with re-spect to their prominent use in catalysis and photoluminescent sensor activity. We have developed photo-physical approach to study measurable properties of the frontier MOs of the complexes, estimate orbital nature of rare long-lived ligand-to-metal charge transfer (LMCT) excited states and also supramolecular interactions between basic components of catalytic systems for polymerization: d0-metal complexes and un-saturated hydrocarbon substrates in fluid systems. In the similar way, the photophysical approach is high-lighted to enable studying fine intermolecular interactions in homogeneous systems with low (catalytic) concentrations of metal complexes that cannot be achieved by other conventional methods. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35397

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Tsutsui, Yuko. "EXPLORING FUNCTIONAL AND FOLDING ENERGY LANDSCAPES BY HYDROGEN-DEUTERIUM EXCHANGE MASS SPECTROMETRY." Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1196199391.

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Zayene, Mariem. "Cooperative data exchange for wireless networks : Delay-aware and energy-efficient approaches." Thesis, Limoges, 2019. http://www.theses.fr/2019LIMO0033/document.

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Avec le nombre croissant d’appareils intelligents à faible puissance, au cours ces dernières années, la question de l’efficacité énergétique a joué un rôle de plus en plus indispensable dans la conception des systèmes de communication. Cette thèse vise à concevoir des schémas de transmission distribués à faible consommation d’énergie pour les réseaux sans fil, utilisant la théorie des jeux et le codage réseau instantanément décodable (IDNC), qui est une sous-classe prometteuse du codage réseau. En outre, nous étudions le modèle de l'échange coopératif de donnée (CDE) dans lequel tous les périphériques coopèrent en échangeant des paquets codés dans le réseau, jusqu’à ce qu’ils récupèrent tous l’ensemble des informations requises. En effet, la mise en œuvre du CDE basé sur l’IDNC soulève plusieurs défis intéressants, notamment la prolongation de la durée de vie du réseau et la réduction du nombre de transmissions afin de répondre aux besoins des applications temps réel. Par conséquent, contrairement à la plupart des travaux existants concernant l’IDNC, nous nous concentrons non seulement sur le délai, mais également sur l’énergie consommée. En premier lieu, nous étudions le problème de minimisation de l’énergie consommée et du délai au sein d’un petit réseau IDNC coopératif, entièrement connecté et à faible puissance. Nous modélisons le problème en utilisant la théorie des jeux coopératifs de formation de coalitions. Nous proposons un algorithme distribué (appelé “merge and split“) permettant aux nœuds sans fil de s’auto-organiser, de manière distribuée, en coalitions disjointes et indépendantes. L’algorithme proposé garantit une consommation d’énergie réduite et minimise le délai de complétion dans le réseau clustérisé résultant. Par ailleurs, nous ne considérons pas seulement l'énergie de transmission, mais aussi la consommation de l'énergie de calcul des nœuds. De plus, nous nous concentrons sur la question de la mobilité et nous analysons comment, à travers la solution proposée, les nœuds peuvent s’adapter à la topologie dynamique du réseau. Par la suite, nous étudions le même problème au sein d’un réseau large et partiellement connecté. En effet, nous examinons le modèle de CDE multi-sauts. Dans un tel modèle, nous considérons que les nœuds peuvent choisir la puissance d’émission et change ainsi de rayon de transmission et le nombre de voisin avec lesquels il peut entrer en coalition. Pour ce faire, nous modélisons le problème avec un jeu à deux étages; un jeu non-coopératif de contrôle de puissance et un jeu coopératif de formation de coalitions. La solution optimale du premier jeu permet aux joueurs de coopérer à travers des rayons de transmission limités en utilisant la théorie des jeux coopérative. En outre, nous proposons un algorithme distribué “merge and split“ afin de former des coalitions dans lesquelles les joueurs maximisent leurs utilités en termes de délai et de consommation d’énergie. La solution proposée permet la création d’une partition stable avec une interférence réduite et une complexité raisonnable. Nous démontrons que la coopération entre les nœuds au sein du réseau résultant, permet de réduire considérablement la consommation d’énergie par rapport au modèle coopératif optimal qui maintient le rayon de transmission maximal
With significantly growing number of smart low-power devices during recent years, the issue of energy efficiency has taken an increasingly essential role in the communication systems’ design. This thesis aims at designing distributed and energy efficient transmission schemes for wireless networks using game theory and instantly decodable network coding (IDNC) which is a promising network coding subclass. We study the cooperative data exchange (CDE) scenario in which all devices cooperate with each other by exchanging network coded packets until all of them receive all the required information. In fact, enabling the IDNC-based CDE setting brings several challenges such us how to extend the network lifetime and how to reduce the number of transmissions in order to satisfy urgent delay requirements. Therefore, unlike most of existing works concerning IDNC, we focus not only on the decoding delay, but also the consumed energy. First, we investigate the IDNC-based CDE problem within small fully connected networks across energy-constrained devices and model the problem using the cooperative game theory in partition form. We propose a distributed merge-and-split algorithm to allow the wireless nodes to self-organize into independent disjoint coalitions in a distributed manner. The proposed algorithm guarantees reduced energy consumption and minimizes the delay in the resulting clustered network structure. We do not only consider the transmission energy, but also the computational energy consumption. Furthermore, we focus on the mobility issue and we analyse how, in the proposed framework, nodes can adapt to the dynamic topology of the network. Thereafter, we study the IDNC-based CDE problem within large-scale partially connected networks. We considerate that each player uses no longer his maximum transmission power, rather, he controls his transmission range dynamically. In fact, we investigate multi-hop CDE using the IDNC at decentralized wireless nodes. In such model, we focus on how these wireless nodes can cooperate in limited transmission ranges without increasing the IDNC delay nor their energy consumption. For that purpose, we model the problem using a two-stage game theoretical framework. We first model the power control problem using non-cooperative game theory where users jointly choose their desired transmission power selfishly in order to reduce their energy consumption and their IDNC delay. The optimal solution of this game allows the players at the next stage to cooperate with each other through limited transmission ranges using cooperative game theory in partition form. Thereafter, a distributed multihop merge-and-split algorithm is defined to form coalitions where players maximize their utilities in terms of decoding delays and energy consumption. The solution of the proposed framework determines a stable feasible partition for the wireless nodes with reduced interference and reasonable complexity. We demonstrate that the co-operation between nodes in the multihop cooperative scheme achieves a significant minimization of the energy consumption with respect to the most stable cooperative scheme in maximum transmission range without hurting the IDNC delay

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Naghibi, Bahman. "Optimal Home Energy Management System for Committed Power Exchange Considering Renewable Generations." Thesis, Curtin University, 2020. http://hdl.handle.net/20.500.11937/83166.

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This thesis addresses the complexity of SH operation and local renewable resources optimum sizing. The effect of different criteria and components of SH on the size of renewable resources and cost of electricity is investigated. Operation of SH with the optimum size of renewable resources is evaluated to study SH annual cost. The effectiveness of SH with committed exchange power functionality is studied for minimizing cost while responding to DR programs.

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McCutcheon, Michael Warren. "Analysis of a 2-3 exchange symmetric neutrino mass matrix." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=79048.

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We present an analysis of the requirements of a 2--3 exchange symmetry in the neutrino mass matrix in comparison to the experimentally allowed ranges of neutrino oscillation parameters. The symmetric matrix, being defined at an energy scale appropriate to a right-handed neutrino in a See-saw scheme of mass suppression, is subject to evolution under Supersymmetric Renormalisation Group Equations, in order to interpret the matrix at experimental energies. By way of motivation we discuss the status of neutrino mass in the Standard Model and justify the context of the analysis by examining the mechanisms and evidence for oscillations. We then review the See-saw mechanism and also the process of renormalisation and its implications for bridging disparate energy scales. We present the relevant Renormalization Group Equations and demonstrate the parameterisation of pertinent Renormalization Group effects. Finally, we review previous work analysing this symmetry before updating some of these results and extending the analysis to its global behaviour in the space of both solar and atmospheric neutrino oscillation parameters.

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Koller, Jan. "Analyse des Bietverhaltens eines Kraftwerkbetreibers an der EEX." St. Gallen, 2008. http://www.biblio.unisg.ch/org/biblio/edoc.nsf/wwwDisplayIdentifier/04603916001/$FILE/04603916001.pdf.

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Sumawong, Anannit. "Risk management of energy derivatives : hedging and margin requirements." Thesis, University of Sussex, 2014. http://sro.sussex.ac.uk/id/eprint/53818/.

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The recent growth of exchanges has generated large trading platforms for investors. The largest of these institutions, the Intercontinental Exchange and the Chicago Mercantile Exchange group are now responsible for clearing trades for the majority of investors worldwide and are perhaps, as large commercial banks are, too big to fail. This has attracted attention from international regulating bodies to impose strict risk management standards on the exchanges to ensure financial stability. In this thesis, we identify first, that an investor in the market is strongly affected by margins set by the exchanges in determining the transaction costs of a trade. We discuss the possibility that a volatile margin movement would introduce further risks for such an investor causing them to raise more capital to cover possible margin calls which can perhaps lead to procyclicality. We follow this work by addressing how margins can be determined in adherence to the new laws. Exchanges are now required to set margins based on the Value-at-Risk, hence we search for the best Value-at-Risk method for margining use. Here, we find that the simple Orthogonal Exponentially Weighted Moving Average method is sufficient in forecasting the Value-at-Risk, which contradicts a fair body of the literature who suggests that complex developments of GARCH are superior. We then offer methods for setting and evaluating margin requirements upon the Value-at-Risk estimates, concentrating on producing stable margin requirements. The automated methods produced in our work outperform all other methods available in the literature. Furthermore, we are the first to provide methods for assessing margin stability. Our work is timely in addressing the current affairs of the world economy and is among the first to tackle the margin stability issue in detail.

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Titov, A. I., V. Shklyar, B. L. Reznik, and Burkhard Kämpfer. "Bremsstrahlung in intermediate-energy nucleon reactions within an effective one-beson exchange model." Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-31042.

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Within a covariant effective one-boson exchange model for the T matrix of NN interactions we present detailed calculations of bremsstrahlung cross sections for proton - proton and proton - neutron reactions at beam energies in the 1 GeV region. Besides pure bremsstrahlung processes we consider photons from ∆ decays and contributions from the η → γγ process. At beam energies above 700 MeV the ∆ decay channel dominates the spectra at large photon energies, where the interference between non-resonance processes and the ∆ decay channel becomes also important. Low energy photons stem from pure bremsstrahlung processes. The available experimental data at 730 MeV beam energy is well described. We extrapolate the model down to 280 MeV, where more detailed experimental data exist, and find agreement with angular distributions.

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23

Sagerfors, Jörgen. "Land-atmosphere exchange of CO₂, water and energy at a boreal minerotrophic mire /." Umeå : Dept. of Forest Ecology and Management, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/200704.pdf.

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24

Gittins, Christopher M. (Christopher Michael). "Electronic structure and electronic-vibrational energy exchange in Rydberg states of calcium monofluoride." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/32639.

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25

Clement, Robert J. "Mass and energy exchange of a plantation forest in Scotland using micrometeorological methods." Thesis, University of Edinburgh, 2004. http://hdl.handle.net/1842/14588.

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This thesis presents the energy, water, and carbon budgets of Sitka spruce plantation forest in Scotland over the period 1997 to 2001. The site microclimate is observed to be strongly influenced by the site’s oceanic climate, and canopy development. Atmospheric structure is observed to affect temporal patterns of microclimatological variables while topography is observed to affect microclimatological and flux measurements. Eddy covariance flux measurement theory and methods are examined and specific inadequacies are addressed. Theoretical aspects of eddy covariance that were examined include signal despiking, coordinate rotation, low frequency contributions, as well as correlations for density fluctuations, angle of attack errors, and sonic temperature determination. An analysis of frequency response correction methods was used to determined if superior methods could be identified. Fluxes of momentum were used to verify existing measures of atmospheric turbulence and analysed to identify canopy structure and growth. Sensible heat fluxes were found to have an unexpected negative bias, only a portion of which can be attributed to instrument error. This bias is found to depend upon topography and wind speed but is apparently unrelated to katabatic flow. Large errors in latent heat flux were caused by enhanced tube attenuation and were corrected using improved frequency response corrections. Interannual variability of momentum and sensible heat flux were closely associated with wind speed variability, while interannual variability of NEE was attributable primarily to radiation. The source of variability of latent heat flux was not clearly identifiable. Missing values of latent heat flux were modelled using a canopy conductance model, which incorporated effects of canopy evaporation.

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26

Titov, A. I., V. Shklyar, B. L. Reznik, and Burkhard Kämpfer. "Bremsstrahlung in intermediate-energy nucleon reactions within an effective one-beson exchange model." Forschungszentrum Rossendorf, 1997. https://hzdr.qucosa.de/id/qucosa%3A21931.

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Within a covariant effective one-boson exchange model for the T matrix of NN interactions we present detailed calculations of bremsstrahlung cross sections for proton - proton and proton - neutron reactions at beam energies in the 1 GeV region. Besides pure bremsstrahlung processes we consider photons from ∆ decays and contributions from the η → γγ process. At beam energies above 700 MeV the ∆ decay channel dominates the spectra at large photon energies, where the interference between non-resonance processes and the ∆ decay channel becomes also important. Low energy photons stem from pure bremsstrahlung processes. The available experimental data at 730 MeV beam energy is well described. We extrapolate the model down to 280 MeV, where more detailed experimental data exist, and find agreement with angular distributions.

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27

Mann, Jennifer Erin. "Probing the potential energy surfaces of elementary neutral reactions using dissociative charge exchange." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2008. http://wwwlib.umi.com/cr/ucsd/fullcit?p3335027.

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Thesis (Ph. D.)--University of California, San Diego, 2008.
Title from first page of PDF file (viewed December 5, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.

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28

Brorsson, Ann-Christin. "The Folding Energy Landscape of MerP." Doctoral thesis, Umeå : Department of Biochemistry, Umeå University, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-309.

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29

Rukas, Christopher J. "Prognostic Health Assessment of an Automotive Proton Exchange Membrane Fuel Cell System." Thesis, Rochester Institute of Technology, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1586450.

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Proton exchange membrane fuel cells are a promising technology for the automotive industry. However, it is necessary to develop effective diagnostic tools to improve system reliability and operational life to be competitive in the automotive market. Early detection and diagnosis of fuel cell faults may lead to increased system reliability and performance. An efficient on-line diagnosis system may prevent irreparable damage due to poor control and system fatigue. Current attempts to monitor fuel cell stack health are limited to specialized tests that require numerous parameters. An increased effort exists to minimize parameter input and maximize diagnostic robustness. Most methods use complex models or black-box methods to determine a singular fault mode. Limited research exists with pre-processing or statistical methods. This research examines the effectiveness of a Naïve Bayes classifier on determining multiple states of health; such as healthy, dry, degraded catalyst, and inert gas build-up. Independent component analysis and principal component analysis are investigated for preprocessing. An automotive style fuel cell model is developed to generate data for these purposes. Since automotive applications have limited computational power, a system that minimizes the number of inputs and computational complexity is preferred.

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30

Shi, Jinjun. "Composite Membranes for Proton Exchange Membrane Fuel Cells." Wright State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=wright1214964058.

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31

Melzian, Rocco. "Handelsstrategien im deutschen Elektrizitätsmarkt : Untersuchung der Gebotsstrukturen und agentenbasierte Simulation des EEX-Spothandels /." Düsseldorf : VDI-Verl, 2008. http://d-nb.info/992001315/04.

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32

Ament, Felix. "Energy and moisture exchange processes over heterogeneous land surfaces in a weather prediction model." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=980850878.

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33

Schade, Falk [Verfasser]. "Energy exchange between athlete and vaulting pole: effects on pole vault performance / Falk Schade." Köln : Deutsche Sporthochschule Köln, 2013. http://d-nb.info/107086353X/34.

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34

Rossi, Gianmarco. "modeling of proton exchange membrane water electrolyzer for green hydrogen production from solar energy." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.

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Hydrogen is considered one of the means by which to store energy coming from renewable and intermittent power sources. With the growing capacity of renewable energy sources, a storage system is required to not waste energy. PEM electrolysis provides a sustainable solution for the production of hydrogen and is well suited to couple with energy sources such as solar and wind. This work reports the development of simulation software to estimate the performance of a proton exchange membrane electrolyzer working at atmospheric or low pressure conditions connected to a solar energy source. The electrolyzer is defined from a validated reference semi-empirical model, which allows for simulating the electrochemical, thermal and H2 output flow behaviours with enough precision for engineering applications. An algorithm for a fitting procedure to characterize commercial products, and functions for power modulation have been implemented. A series of simulations have been carried on, starting from real photovoltaic data of input power, and the output values have been discussed, with particular attention to output flow rate, thermal behaviour and the cooling demand in order to preserve the operation of the electrolyzer.

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35

Lim, Gary Lloyd Nogra. "Elucidation of Photoinduced Energy and Electron Transfer Mechanisms in Multimodular Artificial Photosynthetic Systems." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc984185/.

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Multimodular designs of electron donor-acceptor systems are the ultimate strategy in fabricating antenna-reaction center mimics for artificial photosynthetic applications. The studied photosystems clearly demonstrated efficient energy transfer from the antenna system to the primary electron donor, and charge stabilization of the radical ion pair achieved with the utilization of secondary electron donors that permits either electron migration or hole transfer. Moreover, the molecular arrangement of the photoactive components also influences the route of energy and electron transfer as observed from the aluminum(III) porphyrin-based photosystems. Furthermore, modulation of the photophysical and electronic properties of these photoactive units were illustrated from the thio-aryl substitution of subphthalocyanines yielding red-shifted Q bands of the said chromophore; hence, regulating the rate of charge separation and recombination in the subphthalocyanine-fullerene conjugates. These multicomponent photosystems has the potential to absorb the entire UV-visible-NIR spectrum of the light energy allowing maximum light-harvesting capability. Furthermore, it permits charge stabilization of the radical ion pair enabling the utilization of the transferred electron/s to be used by water oxidizing and proton reducing catalysts in full-scale artificial photosynthetic apparatuses.

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36

Yazaydin, Ahmet Ozgur. "Investigations Of New Horizons On H2/o2 Proton Exchange Membrane Fuel Cells." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1054402/index.pdf.

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Proton exchange membrane fuel cells are electrochemical devices which convert the chemical energy of hydrogen into electrical energy with a high efficiency. They are compact and produce a powerful electric current relative to their size. Different from the batteries they do not need to be recharged. They operate as long as the fuel is supplied. Fuel cells, therefore, are considered as one of the most promising options to replace the conventional power generating systems in the future. In this study five PEMFCs
namely EAE1, AOY001, AOY002, AOY003 and AOY004 were manufactured with different methods and in different structures. A test station was built to make the performance tests. Performances of the PEMFCs were compared by comparing the voltage-current (V-i) diagrams obtained during the initial tests at 25 º
C of fuel cell and gas humidification temperatures. AOY001 showed the best performance among all PEMFCs with a current density of 77.5 mA/cm2 at 0.5 V and it was chosen for further parametric studies where the effect of different flow rates of H2 and O2 gases, gas humidification and fuel cell temperatures on the performance were investigated. It was found that increasing fuel cell and gas humidification temperatures increased the performance. Excess flow rate of reactant gases had an adverse effect on the performance. On the other hand increasing the ratio of flow rate of oxygen to hydrogen had a positive but limited effect. AOY001 delivered a maximum current density of 183 mA/cm2 at 0.5 V. The highest power obtained was 4.75 W

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37

Van, der Meulen N. P. (Nicolas Philip). "The cyclotron production of selected radionuclides using medium energy protons." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/21914.

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Thesis (PhD)--Stellenbosch University, 2008.
ENGLISH ABSTRACT: Radiochemical research involving ion exchange chromatography is of paramount importance to the future of radionuclide production at the Radionuclide Production Group (RPG) of iThemba LABS. It is required for the production of high-activity yields of radionuclides to effectively remove impurities and for the safety of the operators performing such productions. The radiochemical separations of some new products from their target material, as well as experiments to determine whether production is viable, are described. 67Ga is currently being produced at the RPG and makes use of zinc targets. With the production of ultra-pure 67Ga, it was necessary to remove any Fe(III) impurities from the final product, such that it may be possible to label peptides with this product. The use of Amberchrom CG161M for this purpose was found to be satisfactory. Interest was shown in 88Y by an overseas company for the manufacture of sources. While a method involving extraction of the radionuclide and the ion exchange thereof using Chelex 100 chelating resin had been published, problems with the production persisted. Three methods, using ion exchange chromatography, were devised to produce the radionuclide, with two of them being adopted for production purposes. Thick-target nuclear data have also recently been accumulated in collaboration with colleagues from ATOMKI, Debrecen, Hungary. There is a large demand for 82Sr for the manufacture of 82Sr/82Rb generators for medical use. A method was developed to manufacture this radionuclide with thicker (32 g) target material, bombarded in the Vertical Beam Target Station (VBTS), and to separate 82Sr from its target material with the use of Purolite S950 chelating resin. 68Ge/68Ga generators are becoming increasingly important in the world of radiopharmaceuticals. A project to develop a local generator was funded by the Innovation Fund and research was performed to produce 68Ge, such that the generator could be manufactured. This involved bombarding thicker Ga targets in the VBTS and performing the chemical separation using AG MP-1 anion exchange resin. The final product was loaded onto generators, although tests performed on different materials to the ones being marketed are also reported in this work. A project was initiated to study the cluster radioactive decay of 223Ac via 14C and 15N emission. To produce 223Ac for these observations, a Th target was bombarded. The 227Pa was separated from the target material using AG MP-1 macroporous anion exchange resin and used as a source, which decayed to 223Ac. The chemical separation and the drying of the final product onto a source plate were completed within approximately 70 minutes from the end of bombardment. The work was performed in collaboration with JINR, Russia, and University of Milan and INFN, Italy. 133Ba has a half-life of over 10 years and is an expensive radionuclide to produce. It has been used in medical and biological studies and there still appears to be a demand for it. A method was devised, utilizing AG50W-X4 cation exchange resin, to separate 133Ba from its CsCl target material. Agricultural specialists in the past have shown an interest in 28Mg, to determine the uptake of the element in fruit. It has long been regarded by some of the local researchers as an interesting project to investigate. It has been determined that the product can be produced in reasonable quantities using LiCl target material, with ten targets being bombarded in series using a 200 MeV proton beam delivered by the Separated Sector Cyclotron. A method, involving the use of Purolite S950 chelating resin, was devised to separate 28Mg from its target material.
AFRIKAANSE OPSOMMING: Radiochemiese navorsing, wat ioonuitruiling chromatografie behels, is van uiterste belang vir die toekoms van die produksie van radionukliede by die Radionukliedproduksiegroep (RPG) van iThemba LABS. Dit is nodig vir die hoë aktiwiteit opbrengs van radionuklied produkte om onsuiwerhede te verwyder en vir die veiligheid van die operateurs wat die produksies moet uitvoer. Die skeiding van nuwe produkte van hulle skyfmateriaal, sowel as eksperimente om vas te stel of ‘n produksie uitvoerbaar is, word in die werk beskryf. 67Ga word tans by RPG vervaardig en maak gebruik van sink as skyfmateriaal. Vir die produksie van “ultra-suiwer” 67Ga was dit belangrik om enige Fe(III) onsuiwerhede uit die finale produk te verwyder om sodoende peptiede merking te kan uitvoer. Die gebruik van Amberchrom CG161M hars was voldoende vir dié eksperiment. ‘n Oorsese maatskappy het belangstelling getoon in 88Y vir die vervaardiging van bronne. Alhoewel ‘n metode wat die ekstraksie van die radionuklied en die ioonuitruiling daarvan met die gebruik van Chelex 100 chelerende hars reeds gepubliseer was, het probleme met die produksie voortgeduur. Drie metodes is opgestel om 88Y te produseer, waarvan twee van die metodes tans gebruik word vir produksie doeleindes. Dik-skyf kerndata is ook versamel in samewerking met kollegas van ATOMKI, Debrecen, Hongarye. Daar is ‘n groot aanvraag vir 82Sr vir die vervaardiging van 82Sr/82Rb generators vir mediese doeleindes. ‘n Metode is ontwikkel om die radionuklied te vervaardig van dikker skyfmateriaal (32 g), in die Vertikale Bundelstasie gebombardeer, en om 82Sr van sy skyfmateriaal te skei met die gebruik van Purolite S950 chelerende hars. 68Ge/68Ga generators is besig om toenemend belangrik te word in die wêreld van radiofarmasie. iThemba LABS kry baie navrae om die produk te vervaardig. Die projek was ook deel van die voorlegging aan die “Innovation Fund” en ‘n manier is ondersoek om 68Ge te vervaardig, wat benodig word om so ‘n generator te laai. Dik Ga skyfmateriaal word in die Vertikale Bundelstasie gebombardeer en ‘n chemiese skeiding is uitgevoer deur gebruik te maak van AG MP-1 anioonuitruiling hars. Die finale produk is op die generators gelaai vir toetsdoeleindes. Toetse is ook op ‘n ander tipe generator uitgevoer en word in die werk beskryf. ‘n Projek is begin om “cluster” radioaktiewe verval van 223Ac, via 14C en 15N emissie, te bestudeer. ‘n Th-skyf is met protone gebombardeer om die 223Ac te produseer vir die eksperiment. 227Pa is vervaardig en geskei van die skyfmateriaal. Dit is gedoen met die gebruik van AG MP-1 makroporeuse anioonuitruiling hars en drooggemaak op ‘n bronplaat, waar dit verval het na 223Ac. Die chemiese skeiding en die droogmaak van die finale produk op ‘n bronplaat is uitgevoer binne 70 minute na Einde van Bombardering (EVB). Die werk is deel van ‘n samewerking met kollegas van JINR, Rusland, en die Universiteit van Milaan, sowel as INFN, Italië. 133Ba het ‘n halveertyd van oor die tien jaar en is ‘n duur produk om te vervaardig. Dit is al gebruik in mediese en biologiese studies en daar is deesdae ‘n redelike aanvraag daarvoor. ‘n Metode is uitgewerk om 133Ba te skei van die CsCl skyfmateriaal met die gebruik van AG50W-X4 katioonuitruiling hars. Spesialiste in landboustudies het in die verlede belangstelling getoon in 28Mg. Dit word gebruik om die absorpsie van dié element in vrugte te ondersoek. Die produk kan vervaardig word met die gebruik van LiCl skyfmateriaal: tot soveel as tien skywe (agter mekaar) word gebombardeer met ‘n 200 MeV protonbundel te iThemba LABS. ‘n Metode, wat Purolite S950 behels, is daargestel om 28Mg van die skyfmateriaal te skei.

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38

Hong, Jin Gi. "Development of process-based model and novel nanocomposite cation exchange membranes for salinity gradient power production." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53530.

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Ocean salinity is a renewable energy source that has not been recognized and could provide an opportunity to capture significant amount of clean energy when it mixes with river water. One of the processes emerging as a sustainable method for capturing energy from seawater is reverse electrodialysis (RED), which generates power via the transport of the positive and negative ions in the water through selective ion exchange membranes (IEMs). RED power generation is relatively close to commercialization, but its application is often limited by system power efficiency in natural water conditions. Although various types of salt ions exist in environmental saline water, most efforts have been focused on sodium chloride as a single ionic source in the water and the effects of other common multivalent ions (e.g., magnesium and sulfate) on power generation remain unexplored. Moreover, the commercial feasibility of RED is highly challenged by the absence of specialized RED membranes. Currently available IEMs are not optimized for RED power conversion systems, but successful operation is highly dependent on the membranes used. Major advances in manufacturing of proper IEMs will be a critical pathway to accelerate large-scale energy conversion by RED. Therefore, this study aimed at advancing our understanding of the RED power system for efficient and stable salinity gradient energy generation. Specifically, it is comprised of three parts. First, a mathematical model is developed for three different monovalent and multivalent ion combinations to determine the effect of different ionic compositions of the feed solution on the power density. Efforts are further made to optimize the RED system with respect to improving power density by investigating the sensitivity of key response parameters such as flow rate ratios and intermembrane distance ratios. Second, novel organic-inorganic nanocomposite cation exchange membranes (CEMs) are synthesized for RED application by introducing functionalized inorganic materials into an organic polymer matrix. The effect of inorganic particle filler loading within the organic polymer matrix on physico- and electrochemical performance is investigated. The results revealed that the increase of functionalized nanoparticle loading controls the effective ion transport in the membrane structure and there exists an optimum amount of nanoparticles (i.e., charged groups), which performs the best in selectively exchanging counter-ions, while excluding co-ionic species. Third, the membrane structure modification is demonstrated to enhance ion transport while maintaining large surface-charged functional groups in the polymer matrix. We have synthesized custom nanocomposite CEMs to tailor porous membrane structures of various thicknesses, aging (evaporation) time, and inorganic nanoparticle loadings. We have further tailored the membrane structure by incorporating different inorganic particle filler sizes. These engineered design approaches are found to be highly effective in obtaining desired physico- and electrochemical properties, which allowed higher ionic current flow throughout the system. Furthermore, for the first time we showed the successful application of tailor-made nanocomposite CEMs in a RED stack and achieved superb power density, which exceeds the power output obtained with the commercially available membranes. In summary, this dissertation has advanced our understanding of salinity gradient energy generation using RED technique. Specifically, computational modeling and simulation study investigates the development and optimization approaches of the RED process for practical application of RED using natural water conditions. Furthermore, the RED membranes developed in this dissertation focuses on fabrication, characterization, and optimization of cation exchange membranes. Overall, the results of this study are anticipated to benefit the future optimization of energy-capturing mechanisms in RED and provide the better pathway for the sustainable salinity gradient power generation.

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39

Menendez-Alonso, Elena. "Trace metal and speciation analysis using ion-exchange and energy dispersive X-ray fluorescence spectrometry." Thesis, University of Plymouth, 2000. http://hdl.handle.net/10026.1/896.

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Studies have been carried out on specific ion-exchange (Dowex 50W-X8 and Dowex 1-X8) and chelation (Chelex-100) resins, in order to determine their physical and chemical characteristics, to understand and explain their limits of function and to optimise their use as substrates in trace metal and speciation measurement by EDXRF. Structural information was obtained by scanning electron microscopy and x-ray microanalysis showing a homogeneous distribution of functional groups and retained ions on both sectioned and whole resins. Particle size experiments performed on Dowex 50W-X8 (38 - 840 µm) showed that this parameter has no effect on the relationship between intensity of fluorescence and concentration or mass of resin. Inter-element effects were not observed in the analysis of multielemental specimens prepared on ion-exchange / chelation media by EDXRF. This indicates that the proposed method has a significant advantage when compared with other methodologies. A theoretical ‘model’, based on the formation of thin films on the surface of the resin beads, has been proposed in order to link and explain the effects observed in these experiments. The use of a batch retention system has shown distinct advantages over using columns in terms of linearity, accuracy, precision, rapidity and simplicity. Parameters such as pH and ionic strength of the solution, concentration of competing ions and volume of the sample have been proven to be critical. The maximum retention capacity has been determined as 3.2, 1.1 and 0.67 mEq/g for Dowex 50W-X8, Dowex 1-X8 and Chelex-100 respectively. The optimum mass of resin for XRF analysis was found to be 0.5 g, for all resins tested. The linear range covered 4 to 5 orders of magnitude. These findings show the potential of the investigated media to overcome instrumental and sample limitations. Based on the physico-chemical information found, methodologies for three different applications of the resins to EDXRF determinations have been developed and their analytical possibilities explored. The multi-elemental determination of metals in sewage sludge digests was achieved by retaining the metals on Dowex 50W-X8 at pH 2 and Chelex-100 at pH 4. Chelex-100 allows quantitative recoveries for Cu and Zn. A wider range of elements was determined on Dowex 50W-X8, although with poorer recoveries (60 - 90%). The limits of detection were 10 - 21 µg when Dowex 50W-X8 was used and 8 - 49 µg for Chelex-100. The method was validated by the analysis of a certified material. The determination of Kβ/Kα intensity ratios for Cr and Mn species and its potential as a tool for direct elemental speciation has also been studied. A difference in Kβ/Kα between the oxidation states of the analytes was only observed during the analysis of solutions of the metal species by EDXRF at the 98% level of confidence. Finally, the speciation and preconcentration of Cr(III) and Cr(VI) in waters has been performed by retention on Dowex 50W-X8 and Dowex 1-X8 followed by EDXRF determination. Efficient recoveries and preconcentration factors of up to 500 were achieved, leading to limits of detection of 30 µg/L for Cr(VI) and 40 µg/L for Cr(III). This method is simple, fast and inexpensive, allowing quantitative recoveries in the speciation of chromium in waste waters.

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40

Wang, Cheng. "Application of the thermoelectric heat exchange module combined with renewable energy for UK domestic heating." Thesis, University of Newcastle upon Tyne, 2017. http://hdl.handle.net/10443/3788.

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This thesis proposes a theoretical study which mainly utilizes experimental test, quantitative data statistics, case study and scenario simulation to ascertain the feasibility of developing a thermoelectric (TE) heating system powered by renewable energy to service for the UK domestic heating demands, and further compete with current domestic heating system to reduce the greenhouse gas emissions. Experimental study results of the space heating application of TE modules in a laboratory environment (19 ◦C-21 ◦C) and outside courtyard low-temperature environment (1 ◦C-5 ◦C) demonstrate that sufficient temperature difference can be achieved with TE modules so as to satisfy UK thermal comfort levels. The heating COP test results of TE modules also suggest an acceptable heat pump efficiency for the domestic heating application. In order to ascertain the potential feasibility of applying renewable energy to power TE modules for supporting the domestic heating, the detailed case study presents a simulated domestic heating application of TE modules to a Pre-1900s mid-terrace UK dwelling using hybrid renewable energy of solar energy and wind energy. Relevant calculation results reveal that a TE heating system, powered by local hybrid renewable energy and energy storage, can partly meet the domestic heating demand and could achieve a theoretical energy saving efficiency of 64.93% and reduce the CO2 emission of 3927.72 kg/year compared with using generic electric heater for the domestic space heating whilst the average heating COP remains at 1.8. These suggest that TE modules can potentially be a solution for domestic indoor space heating whilst using renewable electricity. Consequently and for further evaluating the feasibility of universally applying TE heating system in the UK domestic context, more scenario simulations regarding the domestic heating application of TE modules with hybrid energy supply in different properties across England and Wales are proposed. The simulation results show that with the heating support of TE modules powered by renewable energy, the domestic heating demands can be independently meet for 2-6 months per year (exclude June, July and August) in most common property types and 4-9 months per year in bungalows. Especially in some domestic scenarios of the UK southern regions, both of the domestic heating demands and hot water demands can be potentially meet without extra grid-supply throughout the year. More relevant estimation results suggest that the domestic heating application of TE modules with hybrid energy supply in various scenarios can save minimum 56.11% annual grid electricity consumption in comparison with employing generic electric heaters powered by the grid electricity, and can save 2.89%-84.82% CO2 emission in comparison with condensing boiler heating by burning natural gas, respectively. Meanwhile during some warm months, the excess renewable energy outputs which are not requested by the domestic heating demands can potentially be used to supply the domestic hot water and electric demands which will contribute with more grid energy saving and CO2 emission reduction.

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41

Walikar, Vinayak P. "Multi-year Operation Effect of Geothermal Heat Exchanger on Soil Temperature for Unt Zero Energy Lab." Thesis, University of North Texas, 2013. https://digital.library.unt.edu/ark:/67531/metadc407847/.

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Ground source heat pump (GSHP) uses earth’s heat to heat or cool space. Absorbing heat from earth or rejecting heat to the earth, changes soil’s constant temperature over the multiple years. In this report we have studied about Soil temperature change over multiple years due to Ground loop heat exchanger (GLHE) for Zero Energy Research Laboratory (ZØE) which is located in Discovery Park, University of North Texas, Denton, TX. We did 2D thermal analysis GLHP at particular Depth. For simulation we have used ANSYS workbench for pre-processing and FLUENT ANYS as solver. TAC Vista is software that monitors and controls various systems in ZØE. It also monitors temperature of water inlet/outlet of GLHE. For Monitoring Ground temperatures at various depths we have thermocouples installed till 8ft from earth surface, these temperatures are measured using LabVIEW. From TAC Vista and LabVIEW Reading’s we have studied five parameters in this report using FLUENT ANSYS, they are; (1) Effect of Time on soil Temperature change over Multi-years, (2) Effect of Load on soil temperature change over Multi-years, (3) Effect of Depth on soil temperature change over Multi-years, (4) Effect of Doubling ΔT of inlet and outlet of GLHE on soil temperature change over multi-years and (5) Effect on soil temperature change for same ZØE Laboratory, if it’s in Miami, Florida. For studying effect of time on soil temperature change for multi-years, we have varied heating and cooling seasons. We have four cases they are Case A: GSHP always “ON” (1) 7 months cooling and 5 month cooling and (2) 257 days are cooling and 108 days heating. Case B: GSHP “OFF” for 2 months (1) 7 months cooling and 3 months heating and (2) 6 months cooling and 4 month heating. For Studying Effect of Load on soil temperature change over multi-years, we have considered maximum temperature difference between inlet and outlet for heating and cooling season for simulation. For studying effect of doubling ΔT of inlet and outlet of GLHE, we have doubled the temperature difference between inlet and outlet of GLHP. There will be soil temperature change over year at various depths. For studying Effect of Depth on soil temperature change for multi-years, we have consider 5 depths, they are 4ft, 6ft, 8ft, 110ft and 220ft. The Densities of soil are known from site survey report of ZØE GSHP manufacturers till depth of 13ft. For studying effect of soil temperature over multi-years for same ZØE in Miami, Florida, we have considered equivalent cooling and heating season from weather data for past one year and assuming same number of days of cooling and heating for next 20 years we have simulated for soil temperature change.

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42

Feazell, Monica N. Chambliss C. Kevin. "Synthesis, characterization, and applications of redox-mediated ion exchangers." Waco, Tex. : Baylor University, 2007. http://hdl.handle.net/2104/5097.

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43

Simon, Eric. "Modeling surface-atmosphere exchange of trace gases and energy within and above the Amazon rain forest." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972311262.

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Yip, Ngai Yin. "Sustainable Production of Water and Energy with Osmotically-Driven Membrane Processes and Ion-Exchange Membrane Processes." Thesis, Yale University, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3582181.

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The world population of the 21st century is facing an increasingly challenging energy landscape and declining water quality and availability, further compounded by a rapidly expanding global population against the backdrop of climate change. To meet the challenges of the water-energy nexus in a sustainable manner, existing methods need to be advanced and new technologies developed. Osmotically-driven and ion-exchange membrane processes are two classes of emerging technologies that can offer cost-effective and environmentally sensible solutions to alleviate the pressure on our water and energy demands. The objective of this thesis is to advance forward osmosis (FO), pressure retarded osmosis (PRO), and reverse electrodialysis (RED) for the sustainable production of water and energy.

A main hindrance restricting the progress of osmotically-driven membrane processes, FO and PRO, is the absence of adequate membranes. This work demonstrates the fabrication of thin-film composite polyamide FO membranes that can attain high water flux and PRO membranes capable of achieving power density of 10 W/m², twice the benchmark of 5 W/m² for PRO with natural salinity gradients to be cost-effective. A membrane fabrication platform based on mechanistic understanding of the influence of membrane transport and structural parameters on process performance was developed. The morphology and microstructure of the porous support layer, and hydraulic permeability and salt selectivity of the polyamide active layer were specifically tailored by thoughtful control of the fabrication and modification conditions.

The Gibbs free energy from the mixing of river water with seawater can potentially be harnessed for clean and renewable energy production. This work analyzed the thermodynamics of PRO power generation and determined that energy efficiencies of up to ∼91% can theoretically be attained. The intrinsic limitations and practical constraints in PRO were identified and discussed. Using a tenth of the annual global river water discharge of 37,000 km³ for PRO could potentially produce electricity for over half a billion people, ascertaining natural salinity gradients to be a sizeable renewable source that can contribute to diversifying our energy portfolio.

However, fouling of the membrane support layer can diminish the PRO productivity by detrimentally increasing the hydraulic resistance. Analysis of the water flux behavior and methodical characterization of the membrane properties shed light on the fouling mechanism and revealed the active-support layer interface to play a crucial role during fouling. A brief osmotic backwash was shown to be effective in cleaning the membrane and achieving substantial performance recovery.

Reverse electrodialysis (RED) is an ion-exchange membrane process that can also extract useful work from salinity gradients. This dissertation research examined the energy efficiency and power density of RED and identified a tradeoff relation between the two performance parameters. Energy efficiency of ∼33-44% can be obtained with technologically-available membranes, but the low power densities of < 1 W/m² is likely to be impede the realization of the process. To further advance RED as a salinity energy conversion method, ion-exchange membrane technology and stack design need to be advanced beyond their current limitations.

When analyzed with simulated existing state-of-the-art membranes, PRO exhibited greater energy efficiencies (54-56%) and significantly higher power densities (2.4-38 W/m²) than RED (18-38% and 0.77-1.2 W/m²). The drawback of RED is especially pronounced at large salinity gradients, where the high solution concentrations overwhelm the Donnan exclusion effect and detrimentally diminish the ion exchange membrane permselectivity. Additionally, the inherent different in driving force utilization (osmotic pressure difference for PRO and Nernst potential for RED) restricts RED from exploiting larger salinity gradients to enhance performance. Overall, PRO is found to be the more favorable membrane-based technology for accessing salinity energy.

This work presents pioneering advances for forward osmosis and pressure retarded osmosis membrane development. The fundamental studies of the osmotically-driven membrane processes and ion-exchange membrane processes yielded significant findings that enhanced our mechanistic and thermodynamic understanding of the technologies. The important insights can serve to inform the realization of the emerging membrane-based technologies for the sustainable production of water and energy. The implications of the thesis are potentially far-reaching and are anticipated to shape the discussion on FO, PRO, and RED.

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Pustlauk, Maria. "The preventive effect and its behavioral impact on market manipulations at the European Energy Exchange (EEX)." Doctoral thesis, Humboldt-Universität zu Berlin, 2019. http://dx.doi.org/10.18452/19771.

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Die Arbeit untersucht das Problem der Marktmanipulation in komplexen Märkten aus kartell- und kapitalmarktrechtlicher Perspektive am Beispiel des deutschen Großhandelsmarktes für Strom (European Energy Exchange, EEX) mittels einer ökonomischen und rechtlichen Analyse. Es wird aufgezeigt, dass die Behörden bei der Anwendung des Manipulationstatbestandes auf mögliche Verstöße häufig vor Nachweisproblemen stehen, die im Ergebnis zu einer fehlenden Durchsetzung von Sanktionen trotz Tatbestandsmäßigkeit führen können. Dadurch kommt es zu Lücken in der Rechtsdurchsetzung, die den Abschreckungseffekt der Verbotstatbestände erheblich mindern. Zentrale These der Arbeit ist daher, dass das bestehende Sanktionensystem derart weiterentwickelt werden muss, dass es Rückwirkungen bereits auf die Tatbestandsebene entfaltet, die einen Verstoß gegen das Manipulationsverbot schon aus der ex-ante Perspektive unattraktiv machen. Im ersten Teil werden das Marktumfeld sowie der bestehende Rechtsrahmen untersucht und Manipulationsanreize für die Marktteilnehmer sowie das Fehlen effektiver Instrumente zur Rechtsdurchsetzung festgestellt. Die Sektoruntersuchungen der Europäischen Kommission sowie des Bundeskartellamtes bestätigen diesen Befund. Der zweite Teil setzt auf die positive Analyse auf und schlägt Regulierungsinstrumente zur Änderung des Anreizsystems vor. Dabei ist der Fokus anstelle stetig steigender Bußgelder auf Maßnahmen zur Steigerung der Entdeckungswahrscheinlichkeit zu legen. Es wird vorgeschlagen, das bestehende Kronzeugenprogramm auf Manipulationsfälle auszudehnen und mit einem Belohnungssystem für Whistleblower zu kombinieren, um vermehrt Verstöße aufzudecken und den Abschreckungseffekt der Manipulationstatbestände zu erhöhen. Begleitend ist eine effektive Koordinierung der Maßnahmen staatlicher und privater Durchsetzung des Kartellrechts geboten, um Durchsetzungsdefizite zu beseitigen.
The work examines the problem of market manipulation in complex markets from an antitrust and capital market law perspective, using the example of the German wholesale market for electricity (European Energy Exchange, EEX) and applying the methodology of the economic analysis of law. It is shown that authorities applying the ban of market manipulations on potential infringements regularly face problems of proving a breach of the law which may result in a lack of enforcement of sanctions. Considerable gaps in enforcement result that may reduce the deterrent effect of the prohibition significantly. The central thesis of this work is therefore, that an evolution of the existing system of sanctions is required such that it exerts repercussions on market participants´ reasoning that make an offence unattractive already from the ex-ante perspective. In the first section, the market conditions as well as the existing legal framework are examined. As a result of this analysis, incentives for manipulation of the market by market participants and the lack of effective instruments for law enforcement are found. The sector inquiries of both, the European Commission and the German Federal Cartel Office confirm this finding. The second section of the work builds upon the positive analysis and proposes regulatory instruments to change the incentive scheme in the market. The focus is placed on measures that increase the probability of detection and punishment instead of the dogma of consistently increasing fines. The central proposal extends the existing leniency program for cartels on manipulation cases and combines it with a reward system for whistleblowers. This approach proposes an increased probability of detection of market manipulations and thereby boosts the deterrent effect of antitrust law. Also, the effective coordination of public and private antitrust enforcement efforts is a necessary accompanying measure to remedy deficiencies of law enforcement.

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Mustafa, M. Y. F. A. "Design and manufacturing of a (PEMFC) proton exchange membrane fuel cell." Thesis, Coventry University, 2009. http://curve.coventry.ac.uk/open/items/272310c1-2614-c525-0f72-77c2c68cc626/1.

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This research addresses the manufacturing problems of the fuel cell in an applied industrial approach with the aim of investigating the technology of manufacturing of Proton Exchange Membrane (PEM) fuel cells, and using this technology in reducing the cost of manufacturing through simplifying the design and using less exotic materials. The first chapter of this thesis briefly discusses possible energy alternatives to fossil fuels, arriving at the importance of hydrogen energy and fuel cells. The chapter is concluded with the main aims of this study. A review of the relevant literature is presented in chapter 2 aiming to learn from the experience of previous researchers, and to avoid the duplication in the current work. Understanding the proper working principles and the mechanisms causing performance losses in fuel cells is very important in order to devise techniques for reducing these losses and their cost. This is covered in the third chapter of this thesis which discusses the theoretical background of the fuel cell science. The design of the fuel cell module is detailed in chapter 4, supported with detailed engineering drawings and a full description of the design methodology. So as to operate the fuel cell; the reactant gases had to be prepared and the performance and operating conditions of the fuel cell tested, this required a test facility and gas conditioning unit which has been designed and built for this research. The details of this unit are presented in chapter 5. In addition to the experimental testing of the fuel cell under various geometric arrangements, a three dimensional 3D fully coupled numerical model was used to model the performances of the fuel cell. A full analysis of the experimental and computational results is presented in chapter 6. Finally, the conclusions of this work and recommendations for further investigations are presented in chapter 7 of this thesis. In this work, an understanding of voltage loss mechanism in the fuel cell based on thermodynamic irreversibility is introduced for the first time and a comprehensive formula for efficiency based on the actual operating temperature is presented. Furthermore, a novel design of a 100W (PEMFC) module which is apt to reduce the cost of manufacturing and improve water and thermal management of the fuel cell is presented. The work also included the design and manufacturing of a test facility and gas conditioning unit for PEM fuel cells which will be useful in performing further experiments on fuel cells in future research work. Taking into consideration that fuel cell technology is not properly revealed in the open literature, where most of the work on fuel cells does not offer sufficient information on the design details and calculations, this thesis is expected to be useful in the manifestation of fuel cell technology. It is also hoped that the work achieved in this study is useful for the advancement of fuel cell science and technology.

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Smith, Richard. "RuO2 Nanorods as an Electrocatalyst for Proton Exchange Membrane Water Electrolysis." ScholarWorks @ UVM, 2015. http://scholarworks.uvm.edu/graddis/527.

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The desire for pure diatomic hydrogen gas, H2(g), has been on the rise since the concept of the hydrogen economy system was proposed back in 1970. The production of hydrogen has been extensively examined over 40 + years as the need to replace current fuel sources, hydrocarbons, has become more prevalent. Currently there are only two practical and renewable production methods of hydrogen; landfill gas and power to gas. This study focuses on the later method; using various renewable energy sources, such as photovoltaics, to provide off-peak energy to perform water electrolysis. Efficient electrolysis takes place in electrochemical cells which maximize performance efficiency with the use of noble metal electrocatalyst. Optimizing these electrocatalyst to be less material dependent, highly durable, and more efficient will support the implementation of power to gas electrolysis into the energy infrastructure. The main focus of this study is to explore RuO2 nanorods as a possible electrocatalyst for Proton Exchange Membrane (PEM) water electrolysis. A PEM electrolyzer cell has been constructed and fitted with a RuO2 nanorod decorated, mixed metal oxide (MMO) ribbon mesh anode catalyst structure. The current density-voltage characteristics were measured for the RuO2 nanorod electrocatalyst while under water feed operation. The electrocatalytic behavior was compared to that of ribbon mesh anode catalyst structures not decorated with RuO2 nanorods; one coated with a Ir/Ta MMO catalyst, the other was stripped of the MMO coating resulting in a Ti ribbon mesh anode. The results of these experiments show increased activity with the RuO2 nanorod electrocatalyst corresponding to a decrease in electrochemical overpotential. Through the collection of experimental data from various electrolyzer cell configurations, these overpotenials were able to be identified, resulting in categorical attributions of the enhanced catalytic behavior examined.

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Amini, Adib. "Sustainable Energy and Nutrient Recovery from Swine Waste." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/4977.

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Swine production represents approximately 40% of the world's meat production, and swine wastes contain high concentrations of organic matter, nitrogen (N) and phosphorus (P). Swine production is intensifying as meat demand increases and concentrated animal feeding operations (CAFOs) are becoming increasingly common, making it difficult to treat the waste generated. A system for holistic treatment of swine waste produced in CAFOs was investigated in this study that sustainably generates energy and recovers N and P as saleable fertilizers. The system uses anaerobic digestion (AD) for methane production and solids stabilization, followed by precipitation of struvite (MgNH4PO4*6H2O) and recovery of N by ion exchange onto natural zeolites. This process is expected to mitigate both eutrophication of receiving waters and greenhouse-gas emissions while generating products that meet agronomic nutrient demands; however, the economic and environmental sustainability remains unknown. The objectives of this study were to: (1) evaluate water quality and the fate of nutrients and ions in each step in the proposed system through pilot and bench scale experiments, (2) evaluate content/quality of struvite precipitates formed in wastewater treatment processes, (3) assess basic composition of zeolite materials that are being considered for use as IX materials, (4) quantify the environmental impact of the proposed system, and (5) estimate the economic benefits and costs of the proposed system. The results of a bench scale evaluation of the system show that although water quality greatly improves throughout the treatment process, the effluent water quality has high concentrations of COD (2,803 mg O2/L) and E. coli (106.3 CFU/100ml). This limits reuse options for the reclaimed water, however a variety of on-farm applications may be suitable. During struvite precipitation, the recovery efficiency of SRP was 87% (60 mg/L recovered); however, although measurements that take into account P in suspended solids show a lower recovery efficiency, they also show higher mass recovery (77% efficiency, 66 mg/L recovered). N recovery during struvite precipitation showed a similar trend, with 49% of TN and 7% of NH4-N being recovered. Struvite recovery can only occur from NH4-N and soluble reactive P. The additional recovery observed is likely due to adsorption of the nutrients onto the precipitate. Therefore, to accurately measure and report recovery, measurements of N and P that take into account suspended solids should be used. In most wastes, magnesium is the limiting constituent for struvite formation, but for swine AD effluents, P is the limiting constituent. Therefore, a higher soluble P concentration would increase recovery potential. The majority of the remaining N and P as well as a significant amount of potassium (K) were recovered during IX. Six struvites from commercial processes as well as our bench-scale experiments were assessed and compared by X-ray diffraction, SEM imaging, and SEM-EDX scans. All samples were confirmed as struvite by XRD, however they varied widely in crystal size and shape. The elemental composition of the samples was similar; however, struvite formed from phosphate mining waste had higher amounts Mg and P, indicating more pure struvite formation. The presence of impurities in some samples was likely due to the reactor design and solids separation methods. XRD was also used to confirm the identity of zeolites. Three clinoptilolites had similar crystal size and elemental composition except for Zeosand [reg] which showed a surface roughness, which likely contributes to higher cation exchange capacity. Chabazite has smaller crystal size and larger pores than clinoptilolite, which also likely contributes to its higher capacity. Life cycle assessment (LCA) was used to evaluate the environmental sustainability of the system and the results suggested that environmental benefits were provided across almost all impact categories. Two alternatives for raising the pH in struvite precipitation (NaOH addition vs. aeration) and two alternatives for zeolite IX materials (chabazite vs. clinoptilolite) were assessed, but there were negligible differences between alternatives. The system was also assessed at a medium and large scale, and the large scale was more environmentally friendly across all categories. Operational impacts were significantly greater than construction impacts; therefore, the environmental impact of the system can be accurately assessed by only including operation. A life cycle cost assessment (LCCA) was also performed on the system and showed a payback period of 39 years for a medium sized system and 15 years for a large size. This, however, is when compared to a "business-as-usual" scenario and does not consider renewable energy credits or government grants. Furthermore, although a larger system is more economically beneficial, this must be balanced with quality of animal care. From a cost standpoint, IX recovery using chabazite is not recommended and struvite precipitation using aeration is more economically beneficial than NaOH addition.

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Howe, Daniel Trusler. "Nuclear Magnetic Resonance Microscopy of NafionÂ®-117 Proton Exchange Polymer Membranes." Thesis, Montana State University, 2004. http://etd.lib.montana.edu/etd/2004/howe/HoweD1204.pdf.

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Deng, Daniel. "Three essays on electricity spot and financial derivative prices at the Nordic power exchange /." Göteborg : Department of Economics, School of Economics and Commercial Law [Nationalekonomiska institutionen, Handelshögskolan], Göteborg University, 2006. http://www.handels.gu.se/epc/archive/00004820/01/Deng%5Ffull.pdf.

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Dissertations / Theses on the topic 'Energy exchange'

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