Dissertations / Theses on the topic 'Energy transfer'
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Muñiz, García Claudia. "Rapid Energy Transfer to an Energy Buffer." Thesis, KTH, Kommunikationssystem, CoS, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-91941.
Full textDetta examensarbete introducerar en ny teknologi som är applicerbar till de flesta mobila och portabla elektriska apparater då dessa behöver energi för att fungera. Detta arbete försöker klippa den sista ledningen den som leder till den primära kraftkällan. Med andra ord, är denna teknik en snabb och effektiv trådlös energiöverföring genom ett starkt, fokuserat närbeläget magnetfält. Tack vare magnetfältets kraftiga dämpning undviks interferens med intilliggande kommunikationssystem eller personskador. Denna energi är överförd till, och lagras inuti en bärbar apparat där endast en liten och enkel sekundärkrets har placerats. Examensarbetsprojektet påbörjades med skapandet av en inledande SPICE datormodell. Modellen möjliggjorde ett enkelt och snabbt sätt att testa både konvergens och genomförbarhet av topologin samtidigt som designen utvecklades från den välkända och vitt använda Switch Power Supply-teknologin till den detaljerade designen och implementationen av prototypen. Modellen stöttade samtidigt den iterativa processen av test och optimering. Alla faser är utförligt beskrivna i rapporten och arbetet visar både teoretiskt och praktiskt att denna idé är genomförbar och möjliggör kraftöverföring.
Ortiz-Hernández, Wilfredo. "Energy transfer in dendrimers." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0009300.
Full textOrtego, Javier Moreno. "Light-controlled energy transfer." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2015. http://dx.doi.org/10.18452/17263.
Full textWith the purpose of designing stable and photomodulable fluorophores for their direct application in subdiffraction microscopy techniques, the synthesis and characterization of new far-red emitting photoswitchable fluorophores was accomplished. Fluorescence emission was efficiently modulated or switched On and Off by the interaction of the photochromic unit with the fluorescent-unit. Additionally, encapsulation experiments in micelles were performed to investigate the water solubility of the synthesized compounds. Finally, potential applications were examined with fluorescence microscopy, encapsulating the dyads in giant uni-lamellar vesicles under biological conditions to explore the feasibility to obtain highly resolved subdiffraction images. Exploiting the advantages of nonlinear processes, the synthesis and characterization of photochromes which are able to be switched indirectly through an initial sensitized event were studied. With this determination a two-photon absorbing triarylamine chromophore was covalently linked to an electron poor azobenzene. In-depth characterization of the excited state dynamics was performed and two photon induced isomerization of the dyad was confirmed. A detailed study of the electrochemical properties was set and guidelines towards the improvement of the system were succinctly mentioned.
Clarkson, Ian Michael. "Energy transfer in lanthanide complexes." Thesis, Durham University, 1999. http://etheses.dur.ac.uk/4498/.
Full textEley, C. D. "Energy transfer in unimolecular reactions." Thesis, University of Reading, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356079.
Full textZhao, Pihong. "Nonradiative energy transfer in solutions." Scholarly Commons, 1994. https://scholarlycommons.pacific.edu/uop_etds/2807.
Full textYu, Shilin. "Reversible electronic energy transfer in rotaxane architectures." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0127/document.
Full textThe focus of this thesis is the establishment and study of reversible electronic energy transfer (REET), following light excitation, between molecular subcomponents within ring-on-thread rotaxane nanometric architectures. When the lowest-lying chromophore excited states are quasi-isoenergetic and kinetics of interchromophore transfer are rapid, REET can be instilled - changing excited-state properties. Pyrene and ruthenium(II) tris(bipyridine) derivatives were chosen as matched chromophores. Rotaxane formation was based on active template copper catalysis (Huisgen and Cadiot-Chodkiewicz reactions) within a pyrene-decorated macrocycle, coupling half threads comprising bulky stopper groups - one of which being Ru(bpy)32+. Prolonged luminescence lifetimes (up to 14 μs), compared to parent Ru(bpy)32+, indicated that reversible electronic energy transfer processes were instilled in a series of rotaxanes of varying structure, which were studied by state-state and time-resolved spectroscopies
Westlund, Arvid, and Oskar Bernberg. "Efficient Energy Transfer for Wireless Devices." Thesis, Uppsala universitet, Fasta tillståndets elektronik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-177255.
Full textDet här projektet är ämnat att hittalämpliga kretsarkitetkturer för braeffektöverföring där energikällorna ärmycket begränsade.Två kretsar ska byggas. Den första skata emot hög växelspänning motsvarandespänningen som uppkommer i ettpiezoelement vilket utsätts för växlandetryck. I det här fallet trycket från enmänniskas fotsteg. Kretsen ska leverera3.3V likspänning.Den andra kretsen ska ta emot en lågväxelspänning, vilken motsvarar spänningfrån en trådlös överföring, och leverera3.3V.Krets 1 blev aldrig testad på grund avett fallerande högspänningsaggregat.Genom att skicka en wav-fil genom en OPförstärkareskulle en simulerad spänningfrån piezoelementet användas. Därefterskulle spänningen likriktas ochkonverteras ner till 3.3V.Krets 2 testades med en signalgeneratorsom spänningskälla. Spänningentransformerades först upp innan denlikriktades och skickades in i enspänningsreglator för att därefter ge ut3.3V. Med en liten levererad effekt frånsignalgeneratorn var det nödvändigt attbegränsa effektåtgången i lasten genompulsbreddmodulering. Effektåtgången ispänningsreglatorn begränsades ocksågenom att stänga av och på IC:n(spänningsregulatorn). När IC:n varavstängd laddades en kondensator upp somsedan tömdes i IC:n då den aktiveradesigen.
Quacquarelli, Francesca Paola. "Energy transfer in directly reconfigurable nanomachines." Thesis, University of Sheffield, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.632820.
Full textGowrie, Sarah. "FTIR emission studies of energy transfer." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531817.
Full textSchmid, Stephan Alexander. "Energy Transfer Processes in Organic Semiconductors." Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.514986.
Full textCampbell, Maya. "Energy transfer processes in erbium elpasolites." Thesis, Birkbeck (University of London), 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265854.
Full textO'Neill, M. "Energy transfer in MGO : Cr'+'3." Thesis, University of Strathclyde, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382415.
Full textRawi, Zaid. "Rotational energy transfer in polyatomic molecules." Thesis, University of Sussex, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390073.
Full textPaton, Keith Richard. "Electromagnetic energy transfer into carbon nanotubes." Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608860.
Full textMoore, Evan Guy. "A macrocyclic scaffold for electronic energy transfer and photoinduced electron transfer /." St. Lucia, Qld, 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17983.pdf.
Full textArmitage, Bruce Alan. "Photoinduced electron transfer, energy transfer and polymerization reactions in phospholipid membranes." Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186212.
Full textSmith, Darrin Lee. "Energy-transfer, electron-transfer, and atom/group-transfer resulting from low-energy ion-surface collisions characterize hydrocarbon, fluorocarbon, and mixed self-assembled monolayers." Diss., The University of Arizona, 2002. http://hdl.handle.net/10150/280208.
Full textKang, Ji-Hwan. "Energy transfer enhancement of photon upconversion systems for solar energy harvesting." Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45846.
Full textSimonson, Carey James. "Heat and moisture transfer in energy wheels." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0014/NQ27431.pdf.
Full textKarhu, Robin. "Targeted Energy Transfer in Bose-Einstein Condensates." Thesis, Linköpings universitet, Teoretisk Fysik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-98279.
Full textRaszewski, Grzegorz [Verfasser]. "Energy transfer in Photosystem II / Grzegorz Raszewski." Berlin : Freie Universität Berlin, 2008. http://d-nb.info/1023260182/34.
Full textJoseph, Daphne Melissa Thow. "Energy and electron transfer in Photosystem Two." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362720.
Full textAndrew, Jeremy James. "Energy transfer in gases and cryogenic liquids." Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303566.
Full textWilson, Graham John. "Energy transfer in gases and cryogenic liquids." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239254.
Full textBorbas, K. Eszter. "Switchable luminescent probes using resonance energy transfer." Thesis, Open University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.412386.
Full textKlaassen, Jody J. (Jody Jon). "Energy transfer processes in methane and trideuteromethan." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/17368.
Full textBavetta, Ryan A. (Ryan Andrew). "An investigation of didactic energy transfer systems." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40399.
Full textIncludes bibliographical references (leaf 24).
New experiments were developed for the freshmen seminar Physics of Energy. The class covers electricity generation and dissipation, and provides experience in analysis and design of electrical and mechanical engineering systems. There was interest in developing a series of new laboratory experiments that would demonstrate methods of energy conversion to students. The experiments are focused on the topic of energy conversion and they introduce topics from electromagnetism to mechanical engineering. The new systems developed include a DC motor kit for learning about motor design and use, a linear synchronous motor for learning about electromagnetism, classical mechanics and ballistics, and an end to end power plant energy conversion laboratory to introduce the topics of heat transfer and process efficiencies.
by Ryan A. Bavetta.
S.B.
Boothby, Clare Elspeth. "Phosphorescence and energy transfer in organometallic systems." Thesis, University of Cambridge, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.614800.
Full textTorres, Garcia Juan de. "Nanophotonic control of Förster resonance energy transfer." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4354.
Full textThe technique of Förster resonance energy transfer (FRET) determines the separation between two molecules at the nanometer scale, where molecular interactions can take place. The phenomenon requires a donor fluorophore transferring its energy in a non-radiative way, through a near-field dipole-dipole interaction, to an acceptor. Nanophotonics achieves accurate control over these interactions by modifying the local density of optical states (LDOS) of a single quantum emitter. We have clearly demonstrated enhanced energy transfer within single FRET pairs confined in single nanoapertures made of gold and also aluminum or in more complex structures like the antenna-in-box design. In particular, we have revealed the strong influence of the mutual dipole orientation on the FRET enhancement using nanostructures. Also, by means of silver nanowires, we have demonstrated a long-range plasmon-mediated fluorescence energy transfer between two nanoparticles separated by micrometer distance. Our results are clearing a new path to improve the energy transfer process widely used in life sciences and biotechnology. Optical nanostructures open up many potential applications for biosensors, light sources or photovoltaics
Al-Ahmadi, Ameenah N. "EXCITATION ENERGY TRANSFER IN QUANTUM-DOT SOLIDS." Ohio University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1146849631.
Full textLeopold, Matthew. "Förster Resonance Energy Transfer in PbS Films." Bowling Green State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1408656943.
Full textBall, Christopher D. "Rotational energy transfer in low temperature molecules /." The Ohio State University, 1998. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487951214940079.
Full textDuarte, Rute Catarina Batista de Carvalho. "Materials for energy: opportunities for technology transfer." Master's thesis, Universidade de Aveiro, 2011. http://hdl.handle.net/10773/7567.
Full textEnergy is a current topic and although due to different motivations (rising fuel costs, environmental issues or supply security) the main goals are common, consume less energy and find alternatives to fossil fuel based technologies. Nowadays, significant efforts towards the implementation of sustainable energy technologies, by delineating strategies and priorities, as well as through developing supporting mechanisms and building scenarios. In Europe this efforts are being taken in order to meet the ambitious and binding energy and climate change objectives for 2020. In the form of electricity, heat, light, mechanical, biological or chemical, energy will become an always more expensive commodity, and therefore there is a great need to manage this resource effectively. New products made from new advanced materials can have a large impact on the energy field. It is intended with this dissertation to better understand the energy problem nowadays, to explore applicability of materials science towards sustainable energy technologies with potential to commercial deployment and to understand in each way the positioning of the University of Aveiro associate laboratory CICECO – Centre for Research in Ceramics and Composites Materials, the largest Portuguese institute in the field of materials science and engineering, is fulfilling these assumptions. Therefore, this analysis aims at gathering information in order to create a tool for strategic decision making.
A energia é uma temática atual e, apesar das diferentes motivações (o aumento do consumo de combustíveis, as questões ambientais ou de segurança de abastecimento), os principais objetivos são comuns, reduzir o consumo de energia e encontrar formas de energia alternativas aos combustíveis fósseis. Actualmente estão a ser desenvolvidos esforços significativos no sentido da implementação de tecnologias de energia sustentável, delineando para tal estratégias e prioridades, assim como desenvolvendo mecanismos de financiamento e projecção de cenários. Na Europa, estes esforços estão a ser desenvolvidos no sentido de cumprir com os objectivos ambiciosos estabelecidos para 2020, no que respeita a energia e às alterações climáticas. Sob a forma de electricidade, calor, luz, mecânica, biológica ou química, a energia vai se tornar uma comodidade cada vez mais cara e, neste sentido, há uma grande necessidade de gerir este recurso de forma eficaz. Novos produtos resultantes do desenvolvimento de novos materiais avançados poderão ter um impacto significativo na área da energia. Pretende-se com esta dissertação analisar a atual problemática energética, explorar a aplicabilidade da ciência dos materiais em tecnologias energéticas sustentáveis com potencial de comercialização e perceber de que forma o posicionamento do Laboratório Associado da Universidade de Aveiro, CICECO - Centro de Investigação em Materiais Cerâmicos e Compósitos, o maior instituto Português em matéria de engenharia e ciência dos materiais, vai ao encontro desses pressupostos. Deste modo, a presente análise pretende reunir informação de forma a criar uma ferramenta de apoio à decisão em termos de desenvolvimento estratégico.
Megow, Jörg. "Excitation energy transfer in pheophorbide a complexes." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2013. http://dx.doi.org/10.18452/16673.
Full textThis thesis investigates the excitation energy transfer in pheophorbide a complexes. The P4 and the P16 molecule consist of four and sixteen pheophorbide a molecules, respectively. The complexes in explicit ethanol solution are investigated utilizing a mixed quantum-classical methodology. Classical molecular dynamics simulations are carried out. The time-dependent Schrödinger equation is solved for a Hamiltonian that depends parametrically on the classical nuclear coordinates. In this thesis a method is introduced which allows the computation of the vibrational contribution in harmonic approximation. The high quality of the method is proven. Three different ansatzes were utilized to compute the time development of the excitation energy transfer within the chromophore complexes. The expansion coefficients that result from the solution of the time-dependent Schrödinger equation are utilized to compute averaged time-dependent populations. Also, the expansion coefficients are used to compute excitation energy transfer rates in second order of the excitonic coupling. Thirdly, the time scale of the excitation energy transfer is derived from the delay-time dependent transient anisotropy. In order to compute the anisotropy, the electromagnetic field is included directly in the Hamiltonian of the system. The excitation energy transfer dynamics is exactly the same for the three approaches. In addition, linear and transient spectra of the chromophor complexes Qy band are computed. For a single pheophorbide a in ethanol, the Qx band and the vibrational progression are calculated. Furthermore, the linear absorption of pheophorbide a and P16 next to a gold nanoparticle is studied. The amplification of the molecular absorption signal due to the presence of the nanoparticle is shown. Finally, a new method is introduced to treat distance and conformation dependent screening of the excitonic coupling parametrically within a mixed quantum-classical description.
Bianchi, Francesco. "Energy Transfer in Organic-Inorganic Semiconductor Structures." Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19286.
Full textIn HIOS structures based on a quantum well and an adjacent organic overlayer, efficient conversion of Wannier excitons into Frenkel excitons via Förster-type resonant energy transfer (FRET) has been demonstrated. The design here in use consists of a spiro-annulated ladder-type quarter-phenyl (L4P-SP3), deposited on ZnO-based single quantum wells (SQW) to obtain incoherent electronic coupling. The SQWs we use are grown with extremely thin (2 nm) capping layer. With photoluminescence excitation and time-resolved spectroscopy, we demonstrate that these hybrid structures exhibit energy transfer from the inorganic material to the organic molecules with an efficiency up to 77%. However, UPS measurements show a type-II energy level alignment between ZnO and the molecular layer, resulting in a very efficient charge separation process (ηCT=0.9) that suppresses the molecular emission. The first idea relies on a fast and highly efficient cascade FRET: following the primary transfer step from the QW, the excitation is conveyed away from the hybrid interface by a secondary transfer-step within the organic layer. As final acceptor we select ladder-type sexiphenyl (L6P). In such a structure, we demonstrate a recovery of the molecular emission by a factor eight, showing that the intermolecular FRET outpaced almost entirely the charge separation process. As alternative option, we tune the energy levels at the interface by introducing an organometallic donor monolayer [RuCp*mes]. The interlayer reduces substantially the ZnO work function, aligning the frontier levels of the inorganic and organic semiconductor. Optical experiments show the benefits of the interlayer: while the FRET efficiency is unaffected, the L4P-SP3 emission and its photoluminescence lifetime increase by a factor of seven, when compared to the same structure without interlayer.
Czuprynski, Kenneth Daniel. "Numerical analysis in energy dependent radiative transfer." Diss., University of Iowa, 2017. https://ir.uiowa.edu/etd/5925.
Full textBenco, John S. "Singlet-singlet and triplet-triplet energy transfer in polychromophoric peptides." Link to electronic thesis, 2000. http://www.wpi.edu/Pubs/ETD/Available/etd-0803100-103547.
Full textZhang, Yufang. "Coupled convective heat transfer and radiative energy transfer in turbulent boundary layers." Phd thesis, Ecole Centrale Paris, 2013. http://tel.archives-ouvertes.fr/tel-00969159.
Full textFerguson, David C. "Intramolecular energy transfer in polychromophores that utilize peptide bridging groups." Link to electronic version, 2000. http://www.wpi.edu/Pubs/ETD/Available/etd-0505100-132458/.
Full textHerman, Leslie. "Ru(II) under illumination: a study of charge and energy transfer elementary processes." Doctoral thesis, Universite Libre de Bruxelles, 2008. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210399.
Full textL’ensemble de notre travail s’est concentré sur ces deux domaines d’applications. Par l’étude de différents processus de transfert de charges/d’énergie au sein des complexes seuls (processus intramoléculaires) ou en interaction avec un environnement spécifique (processus intermoléculaires), nous avons souhaité mettre en évidence l’intérêt de l’utilisation d’un nouveau ligand plan étendu, le tpac, au sein de complexes du Ru(II). Un tel ligand permet en effet de conférer d’une part une affinité élevée des complexes résultants pour l’ADN, et d’autre part, de par sa nature pontante, de connecter des unités métalliques entre elles au sein d’entités supramoléculaires de taille importante.
Les propriétés photophysiques de quatre complexes basés sur le ligand plan étendu tpac, le [Ru(phen)2tpac]2+ (P) et son homologue dinucléaire le [(phen)2Ru tpac Ru(phen)2]4+ (PP) (à base de ligands ancillaires phen), ainsi que le [Ru(tap)2tpac]2+ (T) et son homologue dinucléaire le [(tap)2Ru tpac Ru(tap)2]4+ (TT) (à base de ligands ancillaires tap), ont été étudiées et comparées entre elles.
L’examen de ces propriétés, d’abord pour les complexes seuls en solution, en parallèle avec celles de complexes dinucléaires contenant un ligand pontant PHEHAT, a permis de mettre en évidence l’importance de la nature du ligand pontant utilisé. Ces résultats ont ainsi révélé qu’un choix judicieux du ligand pontant permet de construire des entités de grande taille capables de transférer l’énergie lumineuse vers un centre (cas du ligand PHEHAT), ou, au contraire, de relier entre elles des entités ne s’influençant pas l’une l’autre d’un point de vue photophysique (cas du ligand tpac).
Les propriétés des complexes du tpac, étudiés cette fois en présence de matériel génétique (mononucléotide GMP, ADN ou polynucléotides synthétiques), se sont révélées très différentes selon que le complexe portait des ligands ancillaires phen (P, PP) ou tap (T, TT). Seuls les complexes à base de tap sont en effet photoréactifs envers les résidus guanine. Nous avons dès lors focalisé cette partie de notre travail sur les deux complexes T et TT. Cette photoréaction, ainsi que le transfert d’électron photoinduit entre ces complexes excités et la guanine, ont pu être mis en évidence par différentes techniques de spectroscopie d’émission tant stationnaire que résolue dans le temps, ainsi que par des mesures d’absorption transitoire dans des échelles de temps de la nano à la femto/picoseconde. L’étude du comportement photophysique des complexes en fonction du pH a en outre révélé de manière très intéressante que, pour des études en présence d’ADN, la protonation des états excités des complexes devait être considérée. Les résultats de cette étude nous ont fourni des pistes quant à l’attribution des processus observés en absorption transitoire.
Le transfert d’électron a également fait l’objet d’une étude par des méthodes théoriques. Ces calculs ab initio ont permis de mettre en évidence une faible influence de l’énergie de réorganisation sur la vitesse de transfert d’électron, qui semble dépendre plus sensiblement de la non-adiabaticité du processus, mais surtout de l’énergie libre de la réaction et d’un éventuel couplage à un transfert de proton.
L’ensemble des résultats obtenus avec les complexes T et TT en présence de matériel génétique, qui, de manière assez inattendue, sont très semblables, indiquent que ces complexes présentent tous deux un grand intérêt pour le développement de nouvelles drogues antitumorales photoactivables.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
Tran, Thu-Trang. "Electron and multielectron reaction characterizations in molecular photosystems by laser flash photolysis, towards energy production by artificial photosynthesis." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS320.
Full textThe energy demand of humanity is increasing rapidly, and shows no signs of slowing. Alongside this issue, abuse using fossil fuels is one of the main reasons which leads to an increase in atmospheric CO₂ concentration. These problems have to be solved in terms of both limiting CO₂ emission and finding renewable energy sources to replace fossil fuels. Nowadays, solar energy appears as one of the most effective renewable energy sources. Conversion of solar light energy to electricity in photovoltaics or to chemical energy through photocatalytic processes invariably involves photoinduced energy transfer and electron transfer. In this context, the aim of the thesis focuses on studying photoinduced processes in molecular photosystems using laser flash photolysis. The first theme of this thesis focus on studying single electron transfer in Donor-Acceptor Dyad systems towards optimization efficiency of charge separation and application in the photovoltaic organic solar cell. In the second theme of this thesis, two model systems of artificial photosynthesis were investigated to assess the possibility of stepwise charge accumulation on model molecules. A fairly good global yield of approximately 9% for the two charge accumulation on MV²⁺ molecule was achieved. Then, different photocatalytic systems, which have developed for CO₂ reduction, were studied. Understanding of the photoinduced processes is an important step toward improving the efficiency of reduction of CO₂ in practical photocatalytic systems
Basu, Soumyadipta. "Near-field radiative energy transfer at nanometer distances." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31777.
Full textCommittee Chair: Zhang, Zhuomin; Committee Member: Citrin, David; Committee Member: Hesketh, Peter; Committee Member: Joshi, Yogendra; Committee Member: Peterson, Andrew. Part of the SMARTech Electronic Thesis and Dissertation Collection.
Momeneh, Arash. "Inductive contactless energy transfer systems for residential areas." Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/462809.
Full textEn los últimos años, los sistemas de transmisión de energía sin contacto han sido ampliamente investigados y desarrollados. Como es evidente, en estos la transmisión de energía se realiza sin conexión física. Esta tecnología se suele clasificar de acuerdo al nivel de potencia y el lugar de utilización. Sin embargo, los más usados son los sistemas inductivos de trasmisión de energía sin contacto (Inductive contactless energy transfer systems, ICET) debido a su alta eficiencia. Los sistemas ICET envían la energía eléctrica a las cargas a través de grandes bobinados y transformadores sliding. En estos sistemas, la salida del convertidor y las cargas están directamente conectadas al lado secundario del transformador. Este, tiene la capacidad de moverse a través del bobinado primario. Debido a esta capacidad y a la posibilidad de construir sistemas de gran tamaño, pueden ser usados como sistemas de suministro de energía para receptores móviles. Por otro lado, las tecnologías ICET mejoran la seguridad de los usuarios finales ya que eliminan el riesgo de electrocución, como resultado del uso de transformadores resonantes de alta frecuencia que proveen un aislamiento eléctrico. Esta característica es particularmente importante en ambientes húmedos como las piscinas, jardines y baños. Además, es una buena alternativa para la implementación residencial, en lugar de los sistemas convencionales. La implementación de sistemas ICET en áreas residenciales presenta ciertos retos. En esta tesis de doctorado, se presentan diversas soluciones a estos. En el primer capítulo, el concepto de sistemas de transmisión de energía sin contacto es explicado y se presenta una clasificación de acuerdo al nivel de potencia. En el segundo capítulo, se propone un algoritmo de control adaptativo para sistemas de transmisión de energía sin contacto totalmente controlados. Este algoritmo adaptativo opera dinámicamente con los cambios de carga, alcanzando la máxima eficiencia ante diferentes condiciones de carga. En el capítulo se describe el modelado matemático del algoritmo propuesto. En el tercer capítulo, se introduce un sistema sin contacto inductivo parcialmente controlado como alternativa a la topología totalmente controlada. Se analizan las características de esta nueva topología considerando diferentes técnicas de modulación, incluyendo la modulación de frecuencia, la modulación de fase y la modulación Quantum. Luego, se evalúa el desempeño de esta nueva topología y de identifica la técnica de modulación más adecuada. Finalmente, se presenta el diseño de la nueva topología con la técnica de modulación seleccionada. En el cuarto capítulo se presenta el análisis, diseño e implementación de una técnica simple y efectiva en términos de costo para el suministro energía inalámbrica residencial con múltiples cargas móviles. La topología se basa en una conexión en cascada de un convertidor buck de lazo cerrado y de un inversor resonante de alta frecuencia operando en lazo abierto, que es cargado con varios rectificadores pasivos. El sistema propuesto incluye un transformador sliding para abastecer las cargas móviles, lo que permite una ubicación flexible y segura de las mismas. El análisis teórico y el diseño del sistema propuesto se basan en modelos matemáticos derivados del uso de la aproximación del primer armónico. Se incluyen resultados experimentales para verificar las características del sistema. Finalmente, se presentan las conclusiones más importantes de los resultados obtenidos
Piovesan, Nicola. "Network resource allocation policies with energy transfer capabilities." Doctoral thesis, Universitat Politècnica de Catalunya, 2020. http://hdl.handle.net/10803/669313.
Full textDurante las últimas décadas, los operadores de redes móviles han sido testigos de un aumento exponencial en la demanda de tráfico, principalmente debido a la gran solicitud de servicios de una gran cantidad de usuarios. La tendencia es un aumento adicional tanto en la demanda de tráfico como en la cantidad de dispositivos conectados en los próximos años. Se espera que la carga de tráfico tenga una tasa de crecimiento anual del 53% solo para la red móvil, y la próxima era industrial, que conectará diferentes tipos de dispositivos a la infraestructura móvil, definitivamente exacerbará tal aumento. Las instrucciones actuales anticipan que las redes móviles futuras estarán compuestas por despliegues ultra densos de estaciones base (BS) heterogéneas. En consecuencia, la capa tradicional de Macro BS se complementará o reemplazará con múltiples niveles superpuestos de pequeños BS (SBS), lo que permitirá ampliar la capacidad del sistema. Sin embargo, el uso masivo de la Tecnología de la Información y la Comunicación (TIC) y el despliegue denso de los elementos de la red aumentará el nivel de energía consumida por la infraestructura de telecomunicaciones y su huella de carbono en el medio ambiente. Las estimaciones actuales indican que el 10% de la generación mundial de electricidad se debe a la industria de las TIC y se prevé que este valor alcance el 51% para 2030, lo que implica que el 23% de la huella de carbono por actividad humana se deberá a las TIC. La sostenibilidad ambiental es, por lo tanto, un requisito clave para diseñar redes móviles de próxima generación. Recientemente, el uso de fuentes de energía renovables (RES) para suministrar elementos de red ha atraído la atención de la comunidad investigadora, donde el interés se ve impulsado por el aumento de la eficiencia y la reducción de los costos de los recolectores y dispositivos de almacenamiento de energía, especialmente cuando se instalan para suministrar SBS. Se ha demostrado que dicha solución es ambiental y económicamente sostenible tanto en áreas rurales como urbanas. Sin embargo, las RES conllevarán una mayor complejidad de gestión. De hecho, la energía ambiental es inherentemente errática e intermitente, lo que puede causar una entrada de energía fluctuante y producir una interrupción del servicio. Por lo tanto, es necesario un control adecuado de cómo se drena y equilibra la energía entre los elementos de la red para un diseño de red autosostenible. En esta disertación, nos enfocamos en la energía cosechada a través de paneles solares que se considera la más apropiada debido a la buena eficiencia de los paneles fotovoltaicos comerciales, así como a la amplia disponibilidad de la fuente solar para instalaciones típicas. Las características de esta fuente de energía se analizan en la primera parte técnica de la disertación, al considerar un enfoque basado en la extracción de características de los datos recopilados de radiación de energía solar. En la segunda parte técnica de la tesis presentamos nuestro escenario propuesto. Una federación de BS junto con los cosechadores distribuidos y los dispositivos de almacenamiento forman una microrred, cuyas operaciones son administradas por un sistema de administración de energía a cargo de controlar el presupuesto de energía intermitente y errático de las RES. Consideramos el control de carga como un método para administrar adecuadamente la entrada y el gasto de energía, en función de la demanda de tráfico. Además, en la tercera parte técnica, presentamos la posibilidad de mejorar la eficiencia energética de la red al compartir la energía excedente que puede estar disponible en algunos sitios dentro de la microrred. Finalmente, se propone un controlador centralizado basado en aprendizaje supervisado y de refuerzo en la última parte técnica de la disertación. El controlador está a cargo de operar la red para lograr una utilización eficiente de energía y previene el apagón de SBS
Ernst, Friederike [Verfasser]. "Energy transfer in nanotube-chromophore complexes / Friederike Ernst." Berlin : Freie Universität Berlin, 2013. http://d-nb.info/1043480730/34.
Full textWickham-Jones, C. T. "Studies of vibrational energy transfer of small molecules." Thesis, University of Oxford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371569.
Full textReid, Jonathan Philip. "Vibrational energy transfer in gases at low temperatures." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362081.
Full textStevens, Amy L. "Energy transfer processes in supramolecular light-harvesting systems." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:43833f3a-96b0-432a-9608-8f08a9096be7.
Full textSalter, Robert John. "Energy transfer in fundamental kinetic and photolysis processes." Thesis, University of Leeds, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.534839.
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