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1
Blumenthal, M. D. "Gigahertz quantised charge pumping." Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.596732.
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The aim is to link the unit ampere to the elementary charge e, a true invariant of nature. The high level of control over single electrons needed to realise such a quantum current standard has led to much interest in devices employing Coulomb blockade of tunnelling[2]. The time taken for an electron to tunnel through the barriers defining the dot, limits the output current of such devices to several pA[3,4]. A substantial increase in the current would allow these devices to be of a real practical use as a standard. This thesis explores another pumping mechanism for single charges which does not rely on Coulomb blockade of tunnelling. Single electrons are transported through a periodically formed decoupled quantum dot (QD). The electrons transported can be regarded as particles “surfing” on the time dependent potential of the well generated by the three barriers, rather than tunnelling through the barriers as waves. Two phase-shifted sinusoidal signals applied directly to the metallic finger gates on an etched GaAs/AlGaAs quantum wire, pump the electrons at frequencies of up to f = 3.4 GHz, corresponding to a current level of 0.54 nA. This approach represents an alternative path not only in the realization of a high current high accuracy quantum standard for electrical current but also in single photon production and electron spin based quantum computing.
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Rasmusson, Kristina, and Maria Rasmusson. "NAPL spill modeling and simulation of pumping remediation : NAPL modellering och simulering av pumpning." Thesis, Uppsala University, LUVAL, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-111958.
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This Master Thesis presents TMVOC simulations of a NAPL-spill (non-aqueous phase liquid) and following pumping remediation. TMVOC is a simulation program for three-phase non-isothermal multicomponent flow in saturated-unsaturated heterogeneous media. The models presented are based on an actual remediation project. The aim of the thesis was to study if the historical development of the NAPL-spill could be simulated and how long time the pumping remediation would take. A 3D-model and a radially symmetric cylindrical model were created.
A large effort of the work done was in taking the complex TMVOC model in use and modifying it for the problem at hand. Therefore, the numerical results of the simulations should be considered as preliminary and as forming basis for future studies.
The results from the spill simulation and historical pumping simulation indicated that the spill volume could be less than the estimated 1400 m3, perhaps around 700 m3, assuming a leakage time of 30 years.
The historical pumping simulation of a 700 m3 diesel spill showed good agreement with measured values for some wells, but overestimated the recovery in other wells. The overestimation could be due to the fact that the 3D-model did not take seasonal changes in the groundwater level into consideration. Also, the model did not account for any heterogeneity or compartmentalization in soil material properties that could explain the differences between the wells.
Assuming the same spill of 700 m3, future pumping was simulated. The results from these simulations indicated the remediation time to be long due to fast decreasing mobility of the NAPL phase. The NAPL flow rate to the wells was halved in a couple of years. Much of the NAPL was distributed over a large area at near residual saturation with the highest NAPL saturation found at the opposite side of the pumping wells in the model.
Future simulation studies should address the effect of discretization as well as the effect of uncertainties in material properties e.g. conductivity, residual NAPL saturation and soil heterogeneity.
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Nikhar, Hemant G. "Flow assurance and multiphase pumping." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1180.
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Liu, Guang. "A photovoltaic-powered pumping system." Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/30592.
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This thesis studies the optimal design for a photovoltaic-powered medium-head (30 meters) water pumping system, with the emphasis on improving the efficiency and reducing the maintenance requirements of the electrical subsystem. The reduction of maintenance requirements is realized by replacing the conventional brush-type permanent magnet dc motor with a brushless dc (BLDC) motor. Different BLDC motor control techniques such as position-sensorless operation, sinusoidal and trapezoidal excitations are investigated. The improvement in efficiency is achieved by maximizing the output power from the photovoltaic array and by minimizing the losses in various parts of the electrical sub-system. A microprocessor-based double-loop maximum power tracking scheme is developed for maximization of the photovoltaic array output power. Over 99% utilization factor is achieved for a typical clear day regardless of the season of the year. The system losses are minimized mainly by performing loss analysis and selecting most suitable switching topologies and switching components. Experimental results show that the combined converter-motor efficiency is comparable to those of high-efficiency brush-type dc motor systems.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
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Secrieru, Egor. "Pumping behaviour of modern concretes –." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-234912.
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Pumping is the most efficient transportation and placing method for concrete. Despite the immense progress in the field of concrete technology in the last years, so far there are still neither official regulations nor verified theoretical foundations to be used for the assessment and accurate prediction pumping behaviour of ordinary and high performance concretes. This thesis aims at purposefully investigating pumping of modern concretes and bridging the existing knowledge gap. The main achievement of the present research is the development and verification of a sitecompliant and scientifically based methodology for characterisation and prediction of fresh concrete pumping behaviour. The research focus is set on the importance of the forming lubricating layer (LL) during pumping. Within an extended experimental program, the properties of the LL are captured and quantified. They determine the reduction of friction at the pipe wallconcrete interface and thereby govern the concrete flow. It is proven that the composition and the rheological properties of the forming LL exert an enormous impact on pumping since most of the induced shear stress by pumping pressure is concentrated in this layer. In a further step, the flow pattern of concrete is analytically and numerically determined. The concrete exhibits various principal flow types which are already defined at low flow rates: plug flow in case of strainhardening cementbased composite (SHCC), partial concrete bulk shear in ordinary concretes and pronounced bulk shear for selfcompacting concrete (SCC). The results from the fullscale pumping campaign are confronted with the existing pressure performance nomogram on the determination of pumping parameters. The nomogram’s prediction capacity is extended and verified for highly flowable concretes by replacing the slump and flow table results with the viscosity parameter of the LL. Furthermore, the challenges during pumping of concrete, inter alia, priming of the pipeline, blockage formation and final cleaning, are exemplified, and recommendations for the practitioners are provided. Finally, the transfer of the developed scientifically based and ready to use methodology on site is strongly advocated as a part of the future in situ rheology monitoring concept towards envisaged full automation of concrete production and casting processesDas Pumpen stellt die effektivste Methode für das Fördern und Einbringen von Frischbeton auf der Baustelle dar. Trotz der in den letzten Jahren erreichten deutlichen Fortschritte auf betontechnologischem Gebiet existieren für die Beurteilung der Pumpbarkeit von Beton bisher weder offiziell gültige Vorschriften noch abgesicherte theoretische Grundlagen, die eine zielsichere Vorhersage des Pumpverhaltens von Normal- als auch Hochleistungsbetonen ermöglichen. Die vorliegende Arbeit schließt entsprechende Wissenslücken und befasst sich gezielt mit dem Pumpen moderner Betone. Grundlegenden Erkenntnisgewinn stellt die Entwicklung einer wissenschaftlich fundierten, baustellengerechten Prüfmethodik zur Charakterisierung und Vorhersage des Pumpverhaltens von Frischbeton dar. Der Untersuchungsfokus richtet sich auf die Wirkung der sich beim Pumpvorgang ausbildenden Gleitschicht. Ein umfangreiches Untersuchungsprogramm gestattet die Erfassung und Quantifizierung der Eigenschaften dieser Schicht. Sie bestimmen infolge deutlicher Reduzierung der Reibung an der Grenzfläche zwischen Rohrwandung und Beton die Betonströmung entscheidend. Bewiesen wird, dass Betonzusammensetzung und rheologische Eigenschaften der Gleitschicht maßgebende Auswirkungen auf den Pumpvorgang haben, da sich die pumpdruckinduzierte Scherspannung in dieser Schicht konzentriert. Weiterhin erfolgt sowohl eine analytische als auch numerische Charakterisierung der Betonströmung im Rohr. Nachgewiesen wird, dass sich beim Pumpvorgang betonspezifisch unterschiedliche Strömungsarten einstellen, die bereits bei niedrigen Durchflussmengen definiert sind: Pfropfenströmung in hochduktilen Betonen, partielle Scherung des Kernbetons in Normalbetonen und signifikante Scherung in selbstverdichtenden Betonen. Aus großtechnisch durchgeführten Pumpversuchen gewonnene Ergebnisse werden dem derzeit vorhandenen, verbesserungsbedürftigen Betondruck-Leistungs-Nomogramm zur Einstellung von Parametern an der Betonpumpe gegenübergestellt. Die Vorhersagekapazität des Nomogramms kann durch den Ersatz der Ausbreit- bzw. Setzfließmaßangaben mit Viskositätsangaben der Gleitschicht erweitert und verifiziert werden. Des Weiteren werden baustellenbezogene Herausforderungen im Gesamtprozess des Betonpumpvorgangs, u. a. Vorbereitung der Rohrleitung vor dem Pumpen, Auftreten von Stopfern und Endreinigung exemplarisch dargestellt sowie Empfehlungen für die Praktiker erarbeitet. Schließlich wird der Transfer der in dieser Arbeit entwickelten wissenschaftlich basierten und anwendungsbereiten Methodik als Teil des zukünftigen Konzeptes für die in-situ Rheologie-Überwachung hinsichtlich einer angestrebten vollständigen Automatisierung von Fertigungs- und Einbringprozessen von Beton mit Nachdruck empfohlen
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McPherson, Amy. "A Passive Pumping Microfluidic Coulter Counter." NCSU, 2009. http://www.lib.ncsu.edu/theses/available/etd-11032009-082653/.
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As a result of the growing costs of healthcare technology, there is an increasing need for medical diagnostic tools that provide accurate information in a portable, low-cost platform. A microfluidic device using on-chip passive pumping was characterized for use as a particle counter. A detection circuit interfaced with electrodes in the microfluidic chip to provide an excitation signal and to detect electrical activity. Flow occurred due to a Young-Laplace pressure gradient between a 1.2 mm diameter inlet and a 4 mm diameter reservoir when 0.5 μL fluid droplets were applied to the inlet using a micropipette. Polystyrene particles were enumerated using the resistive pulse technique, in which particles can be detected based on the difference in particle conductivity from that of the surrounding medium. Particles counted using the passive flow method demonstrated mean particle counts that were within 13% of those detected using a syringe pump, while all pumping methods displayed particle counts that were within 16% of the count obtained using a hemacytometer. Three different sample loading patterns were compared; the methods varied only in the order of sample and wash fluid administration. Zero, one, or two wash droplets were loaded after the first of two sample droplets. No statistical difference was detected in the mean particle counts for all loading patterns using the passive method (p > 0.05). This passive pumping method is easily implemented using only a micropipette, thus reducing the cost and complexity of particle enumeration, and the method can be implemented in a point-of-care (POC) device for a highly portable, cost-effective particle counter. These methods obtained particle counts that were also consistent with syringe pumping (p > 0.05).
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Liang, Man. "Na/K ATPase : signaling versus pumping." Toledo, Ohio : University of Toledo, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=mco1173803261.
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Thesis (Ph.D.)--University of Toledo, 2006."In partial fulfillment of the requirements for the degree of Doctor of Philosophy in Biomedical Sciences." Major advisor: Zi-Jian Xie. Includes abstract. Document formatted into pages: iii, 156 p. Title from title page of PDF document. Bibliography: pages 64-67, 97-100, 116-117, 125-155.
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Pinilla, A. E. "Wind-powered pumping systems for Columbia." Thesis, University of Reading, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.353477.
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Dvorak, Gary John. "Economic analysis of irrigation pumping plants." Thesis, Kansas State University, 1985. http://hdl.handle.net/2097/9834.
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Al-Nahwi, Ammar Adnan. "Modeling of industrial pumping system dynamics." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/38116.
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Gray, Dodd (Dodd J. ). "Thermal pumping of light-emitting diodes." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/76963.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 129-135).
The work presented here is a study of thermally enhanced injection in light-emitting diodes (LEDs). This effect, which we refer to as "thermal pumping", results from Peltier energy exchange from the lattice to charge carriers when current is injected into an LED. For an applied voltage V such that qV < (hw), where q is the electron charge and (hw) is the average emitted photon energy, thermal pumping can greatly enhance the wall plug efficiency of an LED. Thermal pumping can even give rise to LED wall plug efficiency greater than one, which corresponds to electroluminescent cooling of the diode lattice. Thermal pumping and electroluminescent cooling will be studied through numerical modeling and experiment. Our results include the first ever experimental demonstration of electroluminescent cooling in an LED. Finally we use the intuition gained from the study of thermal pumping to design an LED for maximized optical power output with 100% wall plug efficiency.
by Dodd Gray.
M.Eng.
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Favorskiy, Igor. "Optical pumping in Silicon thin films." Phd thesis, Ecole Polytechnique X, 2013. http://pastel.archives-ouvertes.fr/pastel-00950979.
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Grâce à un long temps de vie de spin, le silicium est un matériau prometteur pour l'électronique de spin. Mais les approches classiques d'étude de la dynamique de spin basées sur la luminescence polarisée ne peuvent pas être utilisées dans ce matériau à cause du faible couplage spin-orbite et du gap indirect. Dans ce travail, nous avons étudié la polarisation de spin des électrons de conduction créée en condition de pompage optique par spectroscopie de photoémission. La surface du silicium est activée en affinité négative par dépôt de césium et d'oxygène de sorte que les électrons photoexcités avec une énergie proche du gap peuvent émis dans le vide. Nous utilisons un laser accordable qui permet de mesurer systématiquement le spectre de polarisation pour des énergies d'excitation allant du seuil d'absorption jusqu'à la bande Gamma2- au-dessus du gap direct. Nous avons obtenus les spectres de polarisation à partir de couches minces SOI d'épaisseurs différentes. A partir de ces résultats, nous déterminons la valeur de paramètres importants de la structure de bande comme le gap direct ou l'énergie du couplage spin-orbite. Cependant, contrairement aux prédictions, lorsque l'épaisseur de la couche de silicium diminue jusqu'à des valeurs inférieures à la longueur de diffusion de spin, la polarisation en spin des électrons émis reste proche de zéro (-0.4%), remettant en cause l'interprétation directe des valeurs théoriques de la polarisation initiale égale à -20%. Une approche théorique a donc été développée sur la base d'un modèle ab initio de structure de bande pour déterminer les spectres de polarisation en spin. Ces calculs sont encore en cours, mais les résultats déjà obtenus sur la structure électronique du silicium sous contrainte indiquent une piste intéressante pour les études futures.
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Orefice, Marcelo de Castro. "Portfolio pumping no mercado acionário brasileiro." reponame:Repositório Institucional do FGV, 2017. http://hdl.handle.net/10438/17967.
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In this dissertation, we discuss the practice of portfolio pumping in Brazil. Although the topic is recurrent in other countries, few studies provide this analysis for the Brazilian case. The statistical study is elaborated in three stages: first, we considered Brazilian investment funds‟ shares for the period from September 2011 to June 2016, estimating daily abnormal returns of those funds based on the Ibovespa, considering and not considering the adjusted beta of the portfolios of those funds. Our results suggest that the practice of portfolio pumping is more frequent at the end of months ex-semester than at the end of semesters. When we consider the beta adjusted to calculate abnormal returns of the funds, we found a greater significance for the existence of this practice. In the second step, the funds were ordered based on their performance in the previous period (by month, semester, and year), which resulted in few relevant results for the analysis of the topic, despite what is proposed by the principal-agent problem literature. In the last step, we analyzed the practice of portfolio pumping in stocks traded on BM&F Bovespa, ordering them by their participation in the portfolios and by their Market Cap. The results indicated that the stocks with greater presence in the portfolios of the investment funds have higher abnormal returns at the end of the periods, reinforcing the thesis that this increase in stock prices in those moments may be a consequence of a deliberate action taken by the managers of those funds
Nesta dissertação, discutimos a prática de portfolio pumping para o caso brasileiro. Embora o tema seja frequente em outros países, são poucos os estudos que realizam essa análise para o Brasil. O estudo estatístico foi realizado em três etapas: na primeira, consideramos o valor das cotas de fundos brasileiros de investimento em ações para o período de setembro de 2011 a junho de 2016, calculando o retorno anormal diário desses fundos com base no Ibovespa, com e sem a consideração do beta ajustado das carteiras desses fundos. O resultado observado sugeriu que a prática de portfolio pumping é mais frequente ao final dos meses ex-semestre do que ao final dos semestres. Quando consideramos o beta ajustado para o cálculo do retorno anormal dos fundos, verificamos maior significância para a existência dessa prática. Na segunda etapa, os fundos foram ordenados com base em seu desempenho no período anterior (mês, semestre e ano), com resultados observados pouco esclarecedores para a análise do tema, diferentemente do que é sugerido pela literatura do problema do principal-agente. Na última etapa, analisamos a prática de portfolio pumping nas ações negociadas na BM&F Bovespa, ordenando-as pela sua participação nos portfólios e pelo seu Market Cap. Os resultados obtidos indicaram que as ações com maior presença nos portfólios dos fundos de investimento têm retornos anormais mais elevados ao final dos períodos, reforçando a tese de que esse aumento nos preços de ações naqueles instantes pode ser uma consequência de uma ação deliberada por parte dos gestores desses fundos.
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Opperman, Adriaan Jacobus. "Analysis of factors influencing the performance of a hydrokinetic coil pump." Thesis, Nelson Mandela Metropolitan University, 2013. http://hdl.handle.net/10948/d1021041.
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A hydrokinetic coil pump (HCP) is described by its name. It is a coil pump driven by the kinetic energy in flowing water. The hydrokinetic energy is converted into mechanical energy by means of a paddle-wheel. The coil pump makes up part of the paddle-wheel and together is called a HCP. The HCP floats in a stream of flowing water while tethered to the bank. The focus of the study was to identify and analyse the factors influencing the HCP. The HCP was then optimized for rural application. Data acquisition took place through experimentation on a full scale experimental platform according to a central composite experimental design. Variables used for the experimentation included; Stream Velocity, Delivery Head, Number of Coils, Discharge, Number of Paddles, Paddle-Wheel rotational speed Overall HCP efficiencies of up to 22 percent were obtained. The efficiency would drop as the stream velocity increased. Stream velocity has been identified as the most influential factor with regards to the variables analysed by this study. The HCP is ideal for rural application. The simplicity of the design ensures reliability as well as an effective water supply solution. The HCP is ideal for slow flowing rivers and can deliver up to 1190ℓ/h to a delivery head of 5m with a stream velocity of 1.2m/s. This is sufficient to supply a small rural community with running water.
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Cahill, Brian Patrick. "AC electro-osmotic pumping for microfluidic systems /." Zürich, 2005. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=15856.
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Emilsson, Kent. "Mitral annulus motion in left ventricular pumping." Doctoral thesis, Linköping : Univ, 2001. http://www.bibl.liu.se/liupubl/disp/disp2001/med661s.pdf.
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Brown, Daniel F. Jr. "Single crystal piezoelectric pumping using displacement amplification." Thesis, Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/19124.
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Campana, Pietro Elia. "PV water pumping systems for agricultural applications." Doctoral thesis, Mälardalens högskola, Framtidens energi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-27641.
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Grassland and farmland degradation is considered as one of the worst environmental and economic threats for China. The degradation process negatively affects food and water security, economy, society and climate changes. Photovoltaic water pumping (PVWP) technology for irrigation is an innovative and sustainable solution to curb the grassland degradation. At the same time it can promote the conservation of farmland, especially in remote areas of China. The combination of PVWP technology with water saving irrigation techniques and sustainable management of the groundwater resources can lead to several benefits. These include enhancing grassland productivity, halting wind and rainfall erosion, providing higher incomes and better living conditions for farmers. This doctoral thesis aims to bridge the current knowledge gaps, optimize system implementation and prevent system failures. This work represents thus a step forward to solve the current and future nexus between energy, water and food security in China, using PVWP technology for irrigation. Models for the dynamic simulations of PVWP systems, irrigation water requirements (IWR) and crop response to water have been presented and integrated. Field measurements at a pilot PVWP system in Inner Mongolia have been conducted to analyse the reliability of the models adopted. A revision of the traditional design approaches and a new optimization procedure based on a genetic algorithm (GA) have been proposed to guarantee the match between IWR and water supply, to minimize the system failures and to maximize crop productivity and thus the PVWP system profitability and effectiveness. Several economic analyses have been conducted to establish the most cost effective solution for irrigation and to evaluate the project profitability. The possible benefits generated by the PVWP system implementation have been highlighted, as well as the effects of the most sensitive parameters, such as forage price and incentives. The results show that PVWP system represents the best technical and economic solution to provide water for irrigation in the remote areas compared to other traditional water pumping technologies. The environmental benefits have been also addressed, evaluating the CO2 emissions saving achievable from the PVWP system operation. The assessment of the feasible and optimal areas for implementing PVWP systems in China has been conducted using spatial analysis and an optimization tool for the entire supply chain of forage production. The results show that the potentials of PVWP systems in China are large. Nevertheless, the feasible and optimal locations are extremely sensitive to several environmental and economic parameters such as forage IWR, groundwater depth, and CO2 credits that need to be carefully taken into account in the planning process. Although this doctoral thesis has used China as case study, PVWP technology can be applied for irrigation purposes all over the world both for off- and on-grid applications leading to several economic and environmental benefits.
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Fahy, Nina J. (Nina Jane). "Pumping up : Russian energy and national power." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/43193.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Political Science, 2007.Includes bibliographical references.
Russia has organized its energy industry similarly to a vertically integrated energy corporation. Not only does Russia possess vast oil and gas reserves, it also has capabilities at every step in the production chain. The execution of Russian energy strategy is incredibly intricate and flows from all points including the state, firms, suppliers, degrees of ownership and transit locales. This work reviews five important aspects of Russia's vertical integration strategy. Firstly, Russia is brining the domestic industry under state control. Secondly, it has pushed out particular types of foreign investment in order to gain control of domestic reserves, their monetization and the development of important projects. Thirdly, Russia seeks to keep resource rich states in its near abroad in its sphere of influence in order to keep their supply within its grasp. Fourthly, it manages relations with neighboring states in possession of transit infrastructure to keep supply routes open to markets. Lastly, it invests abroad in order to increase market presence, cut out middlemen, and further build production chains. Russia expects to strengthen its international position, both economically and geopolitically by undertaking this strategy of vertical integration.
by Nina J. Fahy.
S.M.
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Taylor, Jason Matthew 1977. "Shaped ultrafast optical pumping for NMR applications." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/88353.
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Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2002.Includes bibliographical references (leaves 104-108).
by Jason Matthew Taylor.
S.M.
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Farrell, Carl. "Pulse-pumping of cascaded Raman fibre amplifiers." Thesis, University of Southampton, 2010. https://eprints.soton.ac.uk/333166/.
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In this thesis, I investigate cascaded Raman fibre amplifiers (RFAs) pumped with shaped optical pulses delivered from a Yb doped fibre MOPA source. RFAs offer the potential to generate gain at any arbitrary wavelength with an appropriate pump source, limited only by the fibre’s transparency range. The use of a counter-propagating signal and pump creates a continuous gain, despite the instantaneous nature of stimulated Raman scattering (SRS). A high power Yb doped fibre source emitting around the 1050 to 1100 nm region offers a flexible pump source that can in principle be used to generate gain for any signal from ~1100 to 2000 nm in a silica-based fibre via cascaded SRS. This opens up opportunities for an ultrabroadband amplifier with unmatched spectral width. Furthermore, by using a pump source that is in a MOPA configuration there is a high degree of control over the output characteristics which offers the potential of near-instantaneous electronic control of ultra-broadband Raman gain spectra. In the simplest configuration, cascaded Raman wavelength shifting across a wide range of wavelengths using single-level pump pulses (i.e., approximate super-Gaussian pulses) is investigated. Using a silica-based highly nonlinear fibre (HNLF), cascaded Raman wavelength shifting up to seven Stokes orders is demonstrated and counter-propagating gain measurements are made across all seven Stokes orders. From a pump wavelength of 1064 nm, the peak gain of the 7th Stokes order was ~1575 nm which demonstrated the potential for gain covering more than 500 nm. I believe this is the first time such a measurement has been undertaken. Other fibre types were also studied for comparison. Furthermore, the noise performance and gain saturation properties of cascaded RFAs were investigated, as well. In a more advanced configuration, the Raman gain spectra produced from pumping the HNLF with step-shaped pump pulses are investigated. Such pulses consist of multiple levels with different, controllable, instantaneous powers. By adjusting the power of each step appropriately I show that different parts of the pulse transfer their energy to different Stokes orders, leading to a controllable gain spectrum covering multiple Stokes orders at the same time. I further study how the gain spectrum can be controlled by manipulating the individual duty cycle of each section of the step-shaped pump pulses as well as using multiple pump wavelengths in a time-division multiplexed pumping scheme. Single and dual wavelength pumping of various fibres with step-shaped pulses was experimentally demonstrated. Raman gain spectra spanning two and three Stokes orders and covering over 100 nm were realised. Computer simulations are also carried out for pumping with more than two pump wavelengths and for gain spectra targeting gain simultaneously up to seven Stokes orders and covering up to ~500 nm. This shows that the use of step-shaped pulses and multiple pump wavelengths allow for further increase and control of the useable bandwidth.
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Watanabe, Kota. "Non-adiabatic effects in quantum geometric pumping." Kyoto University, 2017. http://hdl.handle.net/2433/225998.
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Cogliati, Joshua Joseph. "Visualizing the pumping lemma for regular languages." Thesis, Montana State University, 2004. http://etd.lib.montana.edu/etd/2004/cogliati/CogliatiJ0805.pdf.
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Franz, Francesco <1994>. "ETF Portfolio and benefits from Volatility Pumping." Master's Degree Thesis, Università Ca' Foscari Venezia, 2022. http://hdl.handle.net/10579/20922.
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There are several strategies to manage our portfolio, and essentially we can divide them into two macro-categories: Active Management and Passive Management. Several studies have confirmed that in the long run, passive management pays more than active but using passive management par excellence (Buy & Hold), the composition of the portfolio can vary over time, no longer reflecting our needs as an investor and perhaps exposing us at more significant risks than we are willing to take. Volatility Pumping (or Rebalancing Premium) is the passive management that allows us to keep fixed quotas within our portfolio (for example, 60% stock and 40% bond) rebalancing periodically or for specific deviation intervals. With my thesis, I will perform simulations using R to verify the performance of a portfolio consisting of an equity ETF and a bond ETF in the presence of a Buy & Hold strategy and compare them with those obtained by rebalancing, verifying whether there is a benefit from the so-called Volatility Pumping.
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Mainland, Marlene Elise. "Analytical and experimental investigation of an efficient viscous pump." Thesis, Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/15832.
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Siyingwa, Bennet. "Reducing Pumping Related Electricity Costs - A Case Study of Three Water Utility Companies in Zambia : Energy Efficiency in Pumping." Thesis, KTH, Energiteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-137984.
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Electric pumps are extensively used in many industrial and commercial applications worldwide and account for about twenty percent of the world’s electrical energy demand. The useful energy consumed by the pumps is less than what they demand due to inefficiency caused by a number of reasons including the mismatch between the rated operating conditions and their actual operating conditions. Some studies including those done by the US Department of Energy, show that as much as 30-50% of energy consumed by pumping systems could be saved through equipment and control changes in the pumping systems. Zambia, like many countries, faces an electricity shortage. Improving energy efficiency in pumping related operations can help save electricity costs and thus promote sustainable development and ultimately reduce global warming. This document discusses various methods of reducing pumping related electricity costs which can be categorised under either mechanical or electrical methods. Preliminary energy audits on some pumping infrastructure for three water utility companies in Zambia were carried out and results showed various opportunities for saving electricity costs. Detailed study on selected pumping infrastructure revealed that as much as fifty four (54%) electricity cost savings could result at one pump station by correcting the operating points of pumps such that the Best Efficiency Points (BEP) on the pump characteristic curves matched the pumping system head requirements.Interactive presentation was done via Skype
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Moraes-Duzat, Rejane. "Analytical and experimental investigation of photovoltaic pumping systems." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=960906029.
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Berber, Feyza. "CMOS temperature sensor utilizing interface-trap charge pumping." Texas A&M University, 2005. http://hdl.handle.net/1969.1/4157.
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The objective of this thesis is to introduce an alternative temperature sensor
in CMOS technology with small area, low power consumption, and high resolution
that can be easily interfaced. A novel temperature sensor utilizing the interfaceâÂÂtrap
charge pumping phenomenon and the temperature sensitivity of generation current
is proposed.
This thesis presents the design and characterization of the proposed temperature
sensor fabricated in 0.18õm CMOS technology. The prototype sensor is characterized
for the temperature range of 27oCâÂÂ120oC. It has frequency output and exhibits linear
transfer characteristics, high sensitivity, and high resolution. This temperature sensor
is proposed for microprocessor thermal management applications.
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Wright, Samuel James. "Quantised charge pumping in a perpendicular magnetic field." Thesis, University of Cambridge, 2010. https://www.repository.cam.ac.uk/handle/1810/265507.
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There are seven base units in the International System of Units; the metre, kilogram, second, kelvin, ampere, mole and candela. Quantum metrology aims to redefine these quantities in terms of fundamental constants of nature such as the Planck, A vogadro and Boltzmann constants. In the electrical domain, the quantum Hall effect and Josephson effect provide quantum standards for resistance and voltage, respectively. Combining them through Ampere's law yields an indirect quantum standard for current. However, a quantum metrological redefinition of the ampere requires a stand-alone source of current that is quantised for values directly related to fundamental constants. Quantised charge transport devices fabricated in semiconductor heterostructure materials are the most promising candidates for a redefinition of the ampere. Our observations of the quantised current produced by a tunable-barrier GaAs/ AlGaAs electron pump in the presence of a perpendicular magnetic field are documented in detail in this thesis. Perhaps the most important observation is an enhancement of the quantisation as a result of the applied field. To determine the accuracy of the quantisation we applied novel measurement techniques and compared the pumped current with an accurate current generated using primary electrical standards. The reader will find an account of our extensive study, demonstrating the most accurate quantised current source for a current greater than 50 pA. By operating multiple pumps in parallel the current is increased without any noticeable loss of accuracy. Our results have motivated the incorporation of tunable-barrier GaAs/ AlGaAs electron pumps into a system for performing the Quantum Metrological Triangle Experiment at the National Physical Laboratory.
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Swoger, James Harvey. "On non-uniform pumping effects in semiconductor lasers." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ30171.pdf.
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Bloch, Tobias A. "Storage and pumping system optimization using genetic algorithms." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0002/MQ40917.pdf.
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Stranna, Andrea. "Testing of RPT in pumping mode of operation." Thesis, Norges Teknisk-Naturvitenskaplige Universitet, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-20656.
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In this project two pump mode tests has been carried out on a model RPT in the Waterpower Laboratory at NTNU. The measurement set up and execution of the tests were the same, except for the method of dissipating energy in the system. In the first test one of the feed pumps in the basement was used as energy dissipator. In the second test a throttle valve was used as energy dissipator.The objective has been to see how the Waterpower Laboratory is suited for such a test. It was also important to test the two different dissipation methods and evaluate which should be preferred when performing a pump mode test.During the tests it was observed that the guide vane angle kept changing. When the results were processed it became evident that the variations in guide vane angle during the tests had a big influence on the measured pump curves. Variations in guide vane angle has not previously been observed during turbine mode testing. It is presumed that the variation in guide vane angles is due to play in the guide vane system and the design of the guide vanes. The guide vanes are Francis vanes, and not RPT vanes. It is assumed that it is the sharp trailing edge of the guide vanes that causes turbulence over the vanes in pump mode, thus making the guide vanes move about within the play of the guide vane system. It is suggested that the guide vane system is replaced with an RPT guide vane system for further testing in pump mode.The two dissipation methods tested were both effective. The throttle valve works best for achieving 0 flow, while the feed pump is easier to regulate. None of the methods showed signs of high noise or vibrations, and both may be used for future tests.
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Dalton, Tracy. "Fault diagnosis of an industrial coolant pumping system." Thesis, University of Hull, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363209.
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Elgendy, Mohammed Ali Mohammed. "Photovoltaic pumping systems with microcontroller-based MPPT control." Thesis, University of Newcastle Upon Tyne, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610979.
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Photovoltaic pumping systems have become a favourable solution for water supply particularly for sunny regions that have no access to an electric grid. The maximization of energy utilization of these systems via maximum power point tracking (MPPT) has not been sufficiently exploited in the literature. As a result, most commercial photovoltaic pumping systems either utilize inefficient MPPT control or do not utilize MPPT control at all thus wasting up to 50% of the available solar power depending on component matching and weather conditions. It is therefore important that the operating behaviour of these systems under MPPT control must be better understood and their reliability proven under practical operating conditions. This thesis details an investigation of the performance characteristics of directly connected photovoltaic pumping systems, systems operated at a constant array voltage, and those utilizing MPPT control. Two hill-climbing MPPT algorithms namely perturb and observe algorithm and incremental conductance algorithm were chosen because of their simplicity and ease of implementation with a low cost microcontroller/DSP. Particular focus is given to the evaluation of the practical implementation of these two MPPT algorithms and the choice of their parameters. A simple and accurate empirical model is derived for each individual component of the system and the system is simulated numerically using the MATLAB/Simulink environment. A comprehensive analysis of the stability and the performance characteristics of the system in different operation modes is presented. The various advantages and drawbacks of each MPPT control technique are identified and energy utilization efficiency is calculated for different weather conditions. Experimental operation of the system was tested using a 1080Wp photovoltaic array connected to a lkW permanent magnet de motor-centrifugal pump set. A power converter was constructed and used as a pump controller to match the motor-pump set with the PV array. A Texas Instruments TMS320F2812 DSP based eZdsp kit was used for real-time control and data acquisition. Data acquisition is accomplished utilizing the real-time data exchange feature of the DSP kit. Practical results show very good agreement with the numerical simulation of the systems.
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Ostojin, Sonja. "Artificial intelligence control of pumping in sewer networks." Thesis, University of Sheffield, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.577679.
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The control strategy for sewer pumping stations currently used by Anglian Water, and most other UK water service providers, is classical on/off switching. This is based simply on the fluid level in the inlet wet well. Such local control can lead to poor performance across a variety of indicators, including energy costs, hydraulic performance and efficiency. Despite the listed issues, the Anglian Water sewerage system is operating at a satisfactory level in terms of conveying flow to treatment. In clean water systems, artificial intelligence and other techniques have been used to optimise pump scheduling and research is now needed to provide similar efficiency gains for sewerage systems. Artificial intelligence is widely used for different control and automation applications in many areas. There is a limited use of optimal control in clean water systems but little or no research has been done to apply these techniques to waste water. To the best of author's knowledge, this research is the first time that within the water sector that Fuzzy logic (FL) has been applied specifically to the control of pumping in sewer networks. This thesis presents details of a FL system developed in dry weather flow (DWF) for control of sewer pumping stations for energy and costs savings. This research was a collaborative project between Anglian Water and the University of Sheffield. The FL controller outperformed the Base case representing current practice in terms of increased energy and costs savings and a lower number of pump s'Aitches. The functionalities of the FL controller were achieved by: • A Genetic Algorithm was used to tune the FL controller by determining the base lengths of the Membership Functions and the locations of the peaks (vertices of the membership functions' two non-base edges). • The Rule Base impact on level control was investigated and representative Rule base designs were chosen for each of the electrical tariffs. • The FIS controller was extended to include pump efficiency. Pump efficiency was then taken into consideration by running close to the optimal pump operating point, not taking into account long term pump degradation. • An ANN prediction model was developed for DWF inflow prediction which was trained, tested and validated on flow data obtained from survey. The ANN model has just two inputs (population and trade flow) and thus a flow survey is no longer required in order to tune the FL controller. • The FL controller represents a general solution which can be successfully transferred to another pumping station with different characteristics: wet well dimensions, min/max levels and different pumps. Customarisation is needed in terms of physical characteristics of pump station. Simulation results were confinned by the live trial. • The FL system was tested for its robustness using a wet weather event flow profiles. It continued to demonstrate an ability to supply energy cost savings under wet weather conditions albeit not as optimally as for DWF. Wet weather flow (WWF) was out of a scope of this research. FL control system would switch to fail-safe operating mode during WWF event (on/off control timer controlled mode with the pump switch on point sets to 90% of maximal level in the wet well). In summary, Anglian Water currently spends £13 million annually on energy for wastewater pumping. Around 10% of pumping stations within Anglian Water could eventually benefit from intelligent control. Energy savings from intelligent control are expected to deliver 5% or better, based on the results of this PhD research project. This would reduce the annual energy bill of the company by a third of a million pounds.
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賴志強 and Chi-keung Lai. "Dynamic response of a variable speed pumping system." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1994. http://hub.hku.hk/bib/B31212360.
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Pelton, Sabine S. "Spin Pumping in Lateral Double Quantum Dot Systems." Master's thesis, University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5369.
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Electron transport in single lateral quantum dot (QD) and parallel lateral double quantum dot (DQD) systems is modeled using semiclassical rate equations. The Zeeman effect, in conjunction with resonant tunneling, is used to select the spin of electrons involved in transport. We show adiabatic spin pumping by periodic variation of the systems' confining parameters, namely the quantum point contacts (QPCs) dictating the boundaries of the dots, and the gate voltage applied to each dot. The limitations of adiabatic spin pumping are subsequently examined by counting the average spin pumped per cycle when frequency and interdot capacitance are adjusted.ID: 031001288; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Adviser: Eduardo Mucciolo.; Title from PDF title page (viewed February 26, 2013).; Thesis (M.S.)--University of Central Florida, 2012.; Includes bibliographical references (p. 109-118).
M.S.
Masters
Physics
Sciences
Physics
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Mays, Cristin Jean. "Ground-coupled heat pump systems: a pumping analysis." Kansas State University, 2012. http://hdl.handle.net/2097/15099.
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Master of ScienceDepartment of Architectural Engineering
Fred Hasler
Ground-coupled heat pump (GCHP) systems use the ground as a heat source or sink that absorbs heat from or rejects heat to the soil, respectively; this is referred to as the geothermal heat exchanger. Apart from the geothermal heat exchanger, there are two other main system components that make up a GCHP system: heat pumps and circulation pumps. This report studies four GCHP pumping systems and makes comparisons between the four using life-cycle cost analyses for six building models. The goal for this analysis was to discover commonalities between the models in order to provide designers insight into which pumping system is the most cost effective. The analysis was performed by first creating energy models to obtain system and zone load information, as well as system part-load data and geothermal heat exchanger performance. From the zone load information, heat pump selections were then performed to indicate the worst case piping path that is required for pump head calculations. Piping layouts were created to establish pipe lengths for the pump head calculations as well. Other piping components such as valves and fittings and the air separator pressure drops were also calculated. Once the pump head calculations were complete for each system, pump schedules were created. From there initial unit and installation costs were determined for each pump, as well as their replacement costs. The part-load data from the energy models were then used to obtain annual pump energy consumption and pump utility cost. Finally, assumptions were made to establish regular and preventative maintenance requirements for each pumping system. Initial and replacement unit costs, annual utility cost and regular and preventative maintenance costs were the components used in the life-cycle cost analysis. Each of these components was converted to 30-year projected costs and added to create a total life-cycle cost for each pumping system. Comparisons were then made and the results showed that a primary pumping system with VFD control and 100% redundancy was the most cost effective system. However, there are other considerations such as controllability, flexibility and availability that might persuade designers to choose one of the other alternate solutions.
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Aboelkassem, Yasser. "Novel Bioinspired Pumping Models for Microscale Flow Transport." Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/28674.
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Bioinspiration and biomimetics are two increasingly important fields in applied science and mechanics that seek to imitate systems or processes in nature to design improved engineering devices. Here, we are inspired and motivated by microscale internal flow transport phenomena in insect tracheal networks, which are observed to be induced by the rhythmic tracheal wall contractions. These networks have been shown to mange fluid very efficiently compared to current state-of-the-art microfluidic devises.
This dissertation presents two versions of a novel bioinspired pumping mechanism that is neither peristaltic nor belongs to impedance mismatch class of pumping mechanisms. The insect-inspired pumping models presented here are expected to function efficiently in the microscale flow regime in a simple channel/tube geometries or a complex network of channels. The first pumping approach shows the ability of inducing a unidirectional net flow by using an inelastic tube or channel with at least two moving contractions. The second pumping approach presents a new concept for directional pumping, namely ``selective pumping in a network.". The results presented here might help in mimicking features of physiological systems in insects and guide efforts to fabricate novel microfluidic devices with improved efficiency.
In this study, both theoretical analysis and Stokeslets-meshfree computational methods are used to solve for the 2D and 3D viscous flow transport in several micro-geometries (tubes, channels and networks) with prescribed moving wall contractions. The derived theoretical analysis is based on both lubrication theory and quasi-steady approximations at low Reynolds numbers. The meshfree numerical method is based on the method of fundamental solutions (MFS) that uses a set of singularized force elements ``Stokeslets'' to induce the flow motions. Moreover, the passive particle tracking simulation approach in the Lagrangian frame of reference is also used to strengthen and support our pumping paradigm developed in this dissertation.Ph. D.
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Rahardjo, Budi. "Analysis of damage to food particles during pumping /." The Ohio State University, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487776801322849.
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Amy, Caleb(Caleb A. ). "Thermal energy grid storage : liquid containment and pumping." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/128992.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2020Cataloged from student-submitted PDF of thesis.
Includes bibliographical references (pages 149-158).
As the cost of renewable energy falls below fossil fuels, the key barrier to widespread sustainable electricity has become availability on demand. Energy storage can enable dispatchable renewables, but only with drastic cost reductions compared to current batteries. In this thesis, I investigate an electricity storage concept that stores electricity as sensible heat in an extremely hot liquid (>2000°C) and uses multi-junction photovoltaics (MPV) as a heat engine to convert it back to electricity on demand hours, or days, later. In addition to a technoeconomic analysis, this thesis focuses experimentally on heating, liquid containment, and pumping. The transfer of the storage liquid is key because it enables conversion to and from electricity and compact, efficient heat transfer. However, operating at these extreme temperatures introduces many practical challenges, so several novel solutions related to containment and pumping are investigated including high-performance heaters, sealing a large multi-part tank with affordable materials, and pumping above 2000°C. The key result is that although affordable silicon can be contained in affordable graphite and pumped at these temperatures, temperature variation in the system causes it the graphite infrastructure to rapidly dissolve and ultimately fail in a matter of hours. Alternative embodiments are proposed with recommendations on areas of future work. The key takeaway from the technoeconomic modeling is that integrating low-cost thermal storage with an inexpensive heat engine can enable an economical approach to electricity storage, even without high round trip efficiencies. Thus, despite the challenges, future work is warranted.
by Caleb Amy.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Mechanical Engineering
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Lai, Chi-keung. "Dynamic response of a variable speed pumping system /." Hong Kong : University of Hong Kong, 1994. http://sunzi.lib.hku.hk/hkuto/record.jsp?B20666305.
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Duthil, Eric Patxi. "Thermoacoustic heat pumping study : experimental and numerical approaches /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?MECH%202003%20DUTHIL.
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Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2003.Includes bibliographical references (leaves 122-129). Also available in electronic version. Access restricted to campus users.
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Mishra, Phoolendra Kumar. "Pumping test inference of saturated/unsaturated aquifer properties." Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/194085.
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Analytical solutions for aquifer response to pumping are commonly used to infer the hydraulic properties of aquifers. This dissertation develops new analytical solutions for the analysis of pumping test data from confined and unconfined aquifer.An analytical solution for flow to a partially penetrating well of infinitesimally small radius in a compressible unconfined aquifer is developed that allows inferring its saturated and unsaturated hydraulic properties from drawdowns recorded in the saturated and/or the unsaturated zone. The effects of unsaturated zoneconstitutive parameters and thickness on drawdowns in the saturated and unsaturated zones as functions of position and time is investigated; the solution is validated against numerical simulations of drawdown in a synthetic aquifer having unsaturated properties described by the van Genuchten (1980) - Mualem (1976)constitutive model; used to analyze drawdown data from a pumping test conducted by the US Geological Survey at Cape Cod,Massachusetts; and corresponding estimates of van Genuchten - Mualem parameters are compared with laboratoryvalues obtained for similar materials in the area.Drawdowns generated by extracting water from a large diameter (e.g. water supply) well are affected by wellbore storage. An analytical solution in Laplace transformed space for drawdown in a uniformanisotropic confined aquifer caused by withdrawing water at a constant rate from a partially penetrating well with storage is developed. When the pumping well is fully penetrating the solution reduces to that of Papadopulos and Cooper (1967); to that of Hantush (1964) when the pumping well has no wellbore storage; to the solution of Theis (1935) when both conditions are fulfilled; and to that of Yang et al. (2006) when the pumping well is partially penetrating, having finite radius but lacking storage. The solutionis validated against synthetic pumping test data and used to explore graphically the effects of partial penetration, wellbore storage and anisotropy on time evolutions of drawdown in the pumping well and in observation wells.The analytical solution for unconfined aquifers is extended to the case of a finite diameter pumping well with storage. The extended analytical solution is used to investigate the effects of storage in the pumping well and delayed piezometer response on drawdowns in the saturated and unsaturated zones as functions of position and time. The solution is validated against numerical simulations of drawdown in a synthetic aquifer having unsaturated properties described by the van Genuchten (1980) - Mualem (1976) model. It is then used to analyze a seven-day pumping test conducted by University of Waterloo researchers at the Canadian Forces Base Borden in Ontario, Canada; and to compare our results with those ofMoench (2008).
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Mao, Deqiang. "Stochastic Analysis of Pumping Tests in Unconfined Aquifers." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/222873.
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The S shaped log log drawdown time curve typical of pumping tests in unconfined aquifers is reinvestigated via numerical experiments. We examine the temporal and spatial evolution of the rate of change in storage in an unconfined aquifer during pumping. This evolution is related to the transition of water release mechanisms from the expansion of water and compaction of the porous medium to the drainage of water from the unsaturated zone above the initial water table and initially saturated pores as the water table falls during the pumping of the aquifer. We conclude that the transition of the water release mechanisms and vertical flow are the cause of the S shaped drawdown time. Cross-correlation analysis is then employed to examine the relationship between hydraulic properties of an unconfined aquifer and pressure observations. The analysis reveals that head observed in the saturated zone at late times along a streamline is positively correlated with the conductivity (K(s)) of the region upstream of the observation location, and negatively correlated with the K(s) of the region downstream of the observation location along the same streamline. Besides, head observations in the saturated zone at the early time are positively correlated with specific storage (S(s)) in a narrow region between the observation and pumping locations. At intermediate and late times, the head positively correlates with the heterogeneity of α (pore-size distribution parameter) in a thin disk-shaped unsaturated region above the pumping and observation locations. Saturated water content θ(s) in the vadose zone directly above the pumping and monitoring locations is found positively correlated with the head observations during the intermediate times and late times.In the end, a stochastic inverse estimation is conducted to jointly interpret a sequential pumping test in a three dimensional unconfined aquifer. K(s), S(s), θ(s) and α are estimated at the same time. The estimated results capture the pattern of the heterogeneous parameters as well as the details with a smooth distribution. The estimated heterogeneous parameter fields produce better head predictions than the traditional homogeneous method.
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Johnston, Colin I. "Optical and electrical pumping of colour-centre media." Thesis, University of St Andrews, 1991. http://hdl.handle.net/10023/13756.
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Within this thesis the exploitation of the large homogeneously broadened bandwidth of the LiF:F+2 colour-centre laser by production of frequency tunable ultrashort optical pulses over the 0.8-1.0mum spectral region has been presented. A synchronously pumped LiF:F+2 colour-centre laser produced pulses of 700fs duration with average powers of 30mW when a colliding-pulse-modelocked travelling-wave cavity was implemented. Passive modelocking of the LiF:F+2 colour-centre laser was achieved over two spectral operating regions centred around 860nm and 930nm when the saturable absorber dyes IR140 and DaQTeC were employed. Pulse durations as short as 180fs and 130fs were obtained at 860nm and 930nm respectively using colliding-pulse-modelocked group-velocity-dispersion compensated resonators. The laser was pumped at a 10% duty cycle throughout. The use of coupled-cavity- modelocking techniques combined with passive modelocking was found to extend both the tuning range of the laser and useful operating lifetime of the saturable dye. A home built NaCl:OH- colour-centre laser which encorporates the stabilised F+2 colour- centre is presented. Output powers of up to 450mW were obtained for input pump powers of 4W and the laser tuned from 1.4-1.8?m. Electroluminescence studies of NaCl, CsI, CsI:Na, CsI:Tl, and KI crystals are also presented in a study to assess the feasibility of obtaining laser action from such materials by electrical excitation. KI is shown to be the favoured laser candidate by this excitation method and evidence of temporal narrowing and signal enhancement of the electroluminescence output is presented.
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Geng, Jianzhao. "Flux pumping for high-Tc superconducting (HTS) magnets." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/268221.
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High Tc superconductors are enabling in the generation of extremely high magnetic fields. Flux pumping is a promising technology which can be used to operate HTS magnets without significant loss. In this decade, several HTS flux pumps based on travelling magnetic waves have been developed, yet their physics is still unclear. This thesis established a framework in the area of flux pumping for HTS coils. It revealed the underlying physics of existing travelling wave flux pumps, which is an important theoretical contribution. Based on the thorough understanding of flux pumping mechanism, the author proposed two novel types of flux pumps. The new inventions make flux pumping much easier, more controllable, and much less energy consuming. These flux pumps may promote the future applications of HTS magnets. This thesis can be a guidebook for researchers and engineers in developing flux pumps.
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Hansen, Brigham Wheeler. "Smart Technologies for Oil Production with Rod Pumping." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/6936.
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This work enables accelerated fluid recovery in oil and gas reservoirs by automatically controlling fluid height and bottomhole pressure in wells. Several literature studies show significant increase in recovered oil by determining a target bottomhole pressure but rarely consider how to control to that value. This work enables those benefits by maintaining bottomhole pressure or fluid height. Moving Horizon Estimation (MHE) determines uncertain well parameters using only common surface measurements. A Model Predictive Controller (MPC) adjusts the stroking speed of a sucker rod pump to maintain fluid height. Pump boundary conditions are simulated with Mathematical Programs with Complementarity Constraints (MPCCs) and a nonlinear programming solver finds a solution in near real-time. A combined rod string, well, and reservoir model simulate dynamic well conditions, and are formulated for simultaneous optimization by large-scale solvers. MPC increases cumulative oil production vs. conventional pump off control by maintaining an optimal fluid level height.
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Wang, Ren-Fu, and 王仁甫. "Local Pumping Source Identification and Pumping Estimation of Groundwater System." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/70527106211116323533.
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碩士國立臺灣大學
土木工程學研究所
99
The purpose of this study is to establish a method for Combining with signal analysis techniques and numerical groundwater model for the identification of local pumping source s and estimate the amount of its pumping .The method of this study is applied to pumping estimation at Hsichou of Jhuoshuei river alluvial fan.This study use ICA to identify the pumping source from observed groundwater level and estimate the amount of pumping source. By model simulations, set pumping wells in the effective diameter of local observation wells and estimate the local pumping to fit the level of pumping amplitude. The method of this study is applied to pumping estimation at Hsichou of Jhuoshuei river alluvial fan .The amount of local pumping at Hsichou(1) shows 4457 ton/day of agricultural pumping and with 7.96cm drawdown, 1730 ton/day of charge-saving pumping A and with 3.09cm drawdown, 2861 ton/day of charge-saving pumping B and with 5.11cm drawdown；The amount of local pumping at Hsichou(2) shows 3698 ton/day of agricultural pumping and with 4.02cm drawdown, 1730 ton/day of charge-saving pumping A and with 3.09cm drawdown, 2971 ton/day of charge-saving pumping B and with 3.23cm drawdown；The amount of local pumping at Hsichou(3) shows 9006 ton/day of agricultural pumping and with 9.79cm drawdown, 1766 ton/day of charge-saving pumping A and with 1.92cm drawdown, 2888 ton/day of charge-saving pumping B and with 3.14cm drawdown.
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Shieh, Jun-Long, and 謝俊隆. "The Operational Strategy of Pumping Station--Case at Chung-Ho Pumping." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/32sa4e.
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碩士國立臺北科技大學
土木與防災研究所
96
Of the flood control pumping stations are the last line of defense. In recent years climate change caused abnormal rainfall intensity larger and became a major test to the pump stations with protection level of five years in return period. To ensure the function of pump stations, in addition to regular maintenance and continuous personnel training, establishment of management systems and appropriate operation mechanisms are essential factors. The study used Storm Water Management Model to simulate the runoff from catchments, the number of activated pumps and the stage of sewage, etc.. Firstly, the study identified the bottleneck of catchments and proposed countermeasures, and further set operational stages of Chung-Ho Pump Station. Finally, the quantity of necessarily activated pump was simulated under circumstances of different stages and rainfall, enable the pumping station staff to have sufficient time in advance to emptying sewage runoff and reduce flooding risk.