Tesis sobre el tema "Energy and power density"
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Lyu, Xiaofeng. "High-Power-Density Converter for Renewable Energy Application". Diss., North Dakota State University, 2017. https://hdl.handle.net/10365/26345.
Texto completoBriggs, Maxwell H. "Improving Free-Piston Stirling Engine Power Density". Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1432660882.
Texto completoKang, Byoungwoo. "Designing materials for energy storage with high power and energy density : LiFePO₄ cathode material". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/59707.
Texto completo"February 2010." Cataloged from PDF version of thesis.
Includes bibliographical references.
LiFePO₄ has drawn a lot of attention as a cathode material in lithium rechargeable batteries because its structural and thermal stability, its inexpensive cost, and environmental friendliness meet the requirements of power sources for electric vehicles, except high power capability. Strategies to increase the rather sluggish rate performance of bulk LiFePO₄ have focused on improving electron transport in the bulk or at the surface of the material, or on reducing the path length over which the electron and Li* have to move by using nano-sized materials. However, recent evidence indicates LiFePO₄ is pure one dimensional lithium conductor. So, lithium transport is as important as electron transport. Strong anisotropic lithium diffusion results in limited transports of lithium ions in both the bulk and the surface. Reducing the particle size improves the transport of lithium ions in the bulk, and modification of the surface with a lithium-ion conducting material should enhance the transport of lithium ions on the surface. A poorly crystallized lithium phosphate phase on the surface of nanoscale LiFePO₄ is created by using proper off-stoichiometry (LiFeo.9Po.9504.3). The off-stoichiometric strategy leads to small particles less than 50 nm through grain growth restriction and a poorly crystallized lithium phosphate on the surface. The conducting surface phase can not only improve the transport of lithium ions on the surface but also facilitate the access of lithium ions to the surface by reducing anisotropic lithium diffusion on the surface induced by its amorphous nature. The off-stoichiometric material shows extremely high rate performance, achieving reasonable capacity even at 400C (9 s charge/discharge). In this thesis, the main finding is as follows: LiFePO₄ shows fast bulk kinetics and in itself does not limit the rate of charge and discharge. When bulk Li transport is very fast, the battery charging and discharging are limited by other factors such as the surface adsorption and surface transfer of lithium ions and the configuration of a cell. The off-stoichiometric strategy to improve surface transports addresses the right rate-limiting step and reveals the real capability of LiFePO₄.
by Byoungwoo Kang.
Ph.D.
Armutlulu, Andac. "Deterministically engineered, high power density energy storage devices enabled by MEMS technologies". Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/54270.
Texto completoNutter, David B. "Sound Absorption and Sound Power Measurements in Reverberation Chambers Using Energy Density Methods". Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1546.pdf.
Texto completoPatankar, Siddharth. "High-power laser systems for driving and probing high energy density physics experiments". Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/23893.
Texto completoDinca, Dragos. "Development of an Integrated High Energy Density Capture and Storage System for Ultrafast Supply/Extended Energy Consumption Applications". Cleveland State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=csu1495115874616384.
Texto completoAdamson, Jesse Timothy. "Pulse Density Modulated Soft Switching Cycloconverter". DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/315.
Texto completoAmin, Mahmoud. "Efficiency and Power Density Improvement of Grid-Connected Hybrid Renewable Energy Systems utilizing High Frequency-Based Power Converters". FIU Digital Commons, 2012. http://digitalcommons.fiu.edu/etd/600.
Texto completoSignorelli, Riccardo (Riccardo Laurea). "High energy and power density nanotube-enhanced ultracapacitor design, modeling, testing, and predicted performance". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/63027.
Texto completoCataloged from PDF version of thesis.
Includes bibliographical references (p. 161-164).
Today's batteries are penalized by their poor cycleability (limited to few thousand cycles), shelf life, and inability to quickly recharge (limited to tens of minutes). Commercial ultracapacitors are energy storage systems that solve these problems by offering more than one million recharges with little capacitance degradation, recharge times on the order of few seconds, and unlimited shelf life. However, today's ultracapacitors are limited by their low energy stored per unit of volume and weight (5% that of a lithium ion battery), and their high cost (ten times greater than that of lithium ion batteries) per unit of energy stored. This thesis presents vertical carbon nanotubes-based electrodes designed to achieve, when packaged into an ultracapacitor cell, a four to seven times higher power density (7.8 kW/1) and a five times higher energy density (31 Wh/1) than those of activated carbon-based ultracapacitors. Models to predict the energy density, power density, and efficiency of an ultracapacitor cell using vertical carbon nanotube electrodes of a given morphology are described. The synthesis of carbon nanotube electrodes fabricated on thin conducting substrates of tungsten and aluminum that have the target nanotube average diameters and lengths is described along with insights on the thermodynamics of the nanotube growth reaction. The low pressure chemical vapor deposition reactor used to fabricate nanotube electrodes on conducting substrates is described. Electrochemical measurements of electrodes are presented to corroborate electrochemical modeling leading to the performance prediction of carbon nanotube-based ultracapacitors. Finally, some key remaining questions to further advance the understanding of nanotubes as electrode materials for ultracapacitor are presented.
by Riccardo Signorelli.
Ph.D.
Marquez, Daniel Ryan. "Estimating the Acoustic Power of Sources in Nonideal Enclosures Using Generalized Acoustic Energy Density". BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/3977.
Texto completoPatil, Sandeep Kesharsingh. "Modeling and simulations of diphasic composites for development of high energy density dielectrics". Diss., Rolla, Mo. : Missouri University of Science and Technology, 2008. http://scholarsmine.mst.edu/thesis/pdf/Patil_09007dcc804e35ca.pdf.
Texto completoVita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed April 21, 2008) Includes bibliographical references.
Ihrfors, Charlotte. "Binder-free oxide nanotube electrodes for high energy and power density 3D Li-ion microbatteries". Thesis, Uppsala universitet, Strukturkemi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-227451.
Texto completoWang, Ruxi. "High Power Density and High Temperature Converter Design for Transportation Applications". Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/28264.
Texto completoPh. D.
Hoyt, Travis Nathan. "Improvements to Sound Power Measurements for Large, Extended Sources in Semi-Reverberant Rooms Using Generalized Energy Density". BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/7597.
Texto completoBreitenbach, Rene. "Development of Free-standing Nanostructured Iron Oxide Electrodes for High Energy and Power Density 3D Li-ion Microbatteries". Thesis, Uppsala universitet, Strukturkemi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-301338.
Texto completoZhu, Zhiguang. "Enzymatic fuel cells via synthetic pathway biotransformation". Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/51948.
Texto completoPh. D.
Machado, Rogerio Rossi. "Estudo do potencial eólico do pontal do abreu – município de Viamão - RS". reponame:Repositório Institucional da FURG, 2008. http://repositorio.furg.br/handle/1/3489.
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Este trabalho tem por objetivo calcular a energia anual, o FC (fator de capacidade) e o potencial eólico da regiãodo Pontal do Abreu, no município de Viamão no Rio Grande do Sul, para uma instalação contendo umúnico aerogerador do tipo FURLANDER com torre de 100m de altura do cubo, raio do rotor de 50m, potência nominal de 2500kW, velocidade de partida de 3m/s e velocidade de corte de 25m/s. As ferramentas utilizadas no tratamento dos dados levantados foram a planilha Excel e o software WindPro, fazendo um comparativo dos resultados obtidos. Foram usados dois métodos distintos para o cálculo: O método “Measure” baseado nos dados brutos baixados do computador de vento e o método “Weibull” baseado na distribuição de probabilidade de Weibull com parâmetros de escala c de forma k. A densidade de potência a altura do cubo considerada (100m) tem um valor em torno de 500 W/m². A direção predominante do vento é L (leste) seguida de SE (sudeste) e SO (sudoeste). A energia anual calculada fica em torno de 10.000 MWh. O FC para instalação considerada fica em torno de 45%. É apresentada também uma introdução aos principais tópicos que dizem respeito a potencial eólico, cálculos energéticos e parques eólicos.
This work has the finality to calculate the annual energy yield, the capacity factor and the site assessment related to wind potential of Pontal do Abreu, a site located in the town of Viamão, in the state of Rio Grande do Sul, Brazil based upon a study with a single Wind Generator Fuhrlaender Model FL2500 100. The chosen Wind Generator has a hub height on 100 m and a rotor diameter of 100 m too that is well fitted for wind characteristics found in this region, cut in wind speed of 3 m/s and a cut out wind speed of 25m/s. The used tools toperform the studies to do wind data site investigation were the Excel spreadsheet and the software Wind Pro. A comparison of results with both soft wares was documented. It was used two methods in the calculations: The method “Measure” based on row data read from a data logger installed on siteand the method “Weibull” that use a scale factor and a shape factor to define the distribution function that better represent the wind speed measure. The power density at the considered hub height(100m) was found to be 500 W/m². The predominant wind directions in the site are E (East), followed by SE (Southeast) and SO (Southwest) according data collect from wind vanes and register on data logger. The energy yield computed by both methods is about 10000 MWh. The Capacity Factor assessed by data is around 45%. There are presented an introduction of mean topics related to wind potential,energy yield findings and wind farms projects.
Rocco, Davide. "Design and impacts of high power density DC-DC converter in automotive powertrain: a methodological approach". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
Buscar texto completoMasti, Robert Leo. "The Effect of Anomalous Resistivity on the Electrothermal Instability". Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/103737.
Texto completoDoctor of Philosophy
High-energy-density physics (HEDP) is the study of materials with pressures that exceed 1Mbar, and is difficult to reach here on Earth. Inertial confinement fusion concepts and experiments are the primary source for achieving these pressures in the laboratory. Inertial confinement fusion (ICF) is a nuclear fusion concept that relies on the inertia of imploding materials to compress a light fuel (often deuterium and tritium) to high densities and temperatures to achieve fusion reactions. The imploding materials in ICF are driven in many ways, but this dissertation focuses on ICF implosions driven by pulsed-power devices. Pulsed-power involves delivering large amounts of capacitive energy in the form of electrical current over very short time scales (nanosecond timescale). The largest pulsed-power driver is the Z-machine at Sandia National Laboratory (SNL) which is capable of delivering upwards of 30 MA in 130 ns approximately. During an ICF implosion there exists instabilities that disrupt the integrity of the implosion causing non-ideal lower density and temperature yields. One such instability is the Rayleigh-Taylor instability where a light fluid supports a heavy fluid under the influence of gravity. The Rayleigh-Taylor is one of the most detrimental instabilities toward achieving ignition and was one of the main research topics in the early stages of this Ph.D. The study of this instability provided a nice intro for modeling in the HEDP regime, specifically, in the uses of tabulated equations-of-state and tabulated transport coefficients (e.g., resistivity and thermal conductivity). The magneto Rayleigh-Taylor instability occurs in pulsed-power fusion platforms where the heavy fluid is now supported by a magnetic field instead of a light fluid. The magneto Rayleigh-Taylor instability is the most destructive instability in many pulsed-power fusion platforms, so understanding seeding mechanisms is critical in mitigating its impact. Magnetized liner inertial fusion (MagLIF) is a pulsed-power fusion concept that involves imploding a solid cylindrical metal annulus on laser-induced pre-magnetized fuel. The solid metal liners have imperfections and defects littered throughout the surface. The imperfections on the surface create a perturbation during the initial phases of the implosion when the solid metal liner is undergoing ohmic heating. Because a solid metal has a resistivity that increases with temperature, as the metal heats the resistivity increases causing more heating which creates a positive feedback loop. This positive feedback loop is similar to the heating process in a nichrome wire in a toaster, and is the fundamental bases of the main instability studied in this dissertation, the electrothermal instability (ETI). ETI is present in all pulsed-power fusion platforms where a current-carrying material has a resistivity that changes with temperature. In MagLIF, ETI is dominant in the early stages of a current pulse where the resistivity of the metal increases with temperature. An increasing resistivity with temperature is connected to the axially growing modes of ETI which is denoted as the striation form of ETI. Contrary to the striation form of ETI, the filamentation form of ETI occurs when resistivity decreases with temperature and is associated with the azimuthally growing modes of ETI. Chapter 2 in this dissertation details a study of how to simulate striaiton ETI for a MagLIF-like configuration across different resistive magnetohydrodynamics (MHD) codes. Resistivity that decreases with temperature typically occurs in low-density materials which are often in a gaseous or plasma state. Low density plasmas are nearly collision-less and have resistivity definitions that often overestimate the conductivity of a plasma in certain experiments. Anomalous resistivity (AR) addresses this overestimation by increasing a collisional resistivity through micro-turbulence driven plasma phenomenon that mimic collisional behavior. The creation of AR involves reduced-modeling of micro-turbulence driven plasma phenomenon, such as the lower hybrid drift instability, to construct an effective collision frequency based on drift speeds. Because AR directly modifies a collisional resistivity for certain conditions, it will directly alter the growth of ETI which is the topic of Chapter 3. The current on the Z-machine is driven by the capacitor bank through the post-hole convolute, the magnetically insulated transmission lines, and then into the chamber. Magnetically insulated transmission lines have been shown to create low-density plasma through desorption processes in the vacuum leading to a load surrounded by a low-density plasma referred to as a vacuum contaminant plasmas (VCP). VCP can divert current from the load by causing a short between the vacuum anode and cathode gap. In simulations, this plasma would be highly conducting when represented by a collisionally-based resistivity model resulting in non-physical vacuum heating that is not observed in experiments. VCP are current-carrying low-density and high-temperature plasmas which make them ideal candidates to study the role of AR as described in Chapter 4. Chapter 4 investigates the role AR in a VCP would have on striation ETI for a MagLIF-like load.
Ma, Xiaohua Ph D. Massachusetts Institute of Technology. "Understanding and designing high power and high energy density cathode materials for lithium ion batteries by experiments and first principles computations". Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/101862.
Texto completoCataloged from PDF version of thesis.
Includes bibliographical references.
A new layered compound LiNi2/3Sb1/30 2 was synthesized and tested electrochemically to understand the effect of the transition metals on the structural stability of the layered compound upon Li de-intercalation. The electrochemical results show that the structure of LiNi2/3Sb1 /302 degrades upon cycling. XRD pattern refinement and TEM diffraction on the cycled LiNi2/3 Sb1/3O2 indicate that the structure degradation is associated with the migration of Ni into the Li layer. First principles calculation also shows a very low barrier for the migration of a divalent Ni from the transition metal layer to the tetrahedral sites of the lithium layer in the partially delithiated Li2/3Ni2/3Sbl/3O2. The divalent Ni becomes highly mobile because of the strong electrostatic repulsion from the surrounding three Ni3+ and three Sb5+. The effect of the alkali ions on the structural stability in the layered AMO 2 (A = alkali ion; M = transition metals) compounds is discussed by comparing layered LiMnO2 and NaMnO2. The structure of layered LiMnO 2 transforms rapidly into a spinel-like structure upon delithation due to the formation of a Li/Mn dumbbell configuration. However, such kind of dumbbell does not form in NaxMnO2, indicating its better structural stability upon deintercalation. The electrochemical results of NaMnO 2 show a much better capacity retention than that of LiMnO2, confirming that NaMnO2 is more stable than LiMnO2 upon deintercalation. The XRD results of the cycled NaMnO2 also show no significant structural change. The pronounced voltage steps and plateaus of NaMnO2 upon cycling were also investigated. First principles calculations show that the Li diffusivity in LiNi0.5Mn5O4 is in the order of 10-9 cm 2/s, implying that LiNi0.5Mn1.5O4 can be a high rate material even with a large particle size. The electrochemical tests of the micron-sized LiNiO0.5Mn1.5O4 show higher rate capability than nano LiNi0.5Mn1.5O4 by Shaju, et al, indicating that the ionic and electronic transport may not be the rate limiting factors. It was also found that cell configurations, such as separators, mechanical pressure of the cell and the carbon content in the electrode, could dramatically affect the rate capability of the cell. When the cell is highly optimized in configuration, more than half of the theoretical capacity is obtained at a discharge rate of 167C (corresponding to 22 seconds) with a particle size in the range of 3-5 [mu]m, which agrees with the high Li diffusivity by my calculation.
by Xiaohua Ma.
Ph. D.
Pereira, Rosana Aparecida. "Avaliação da microdureza de resina composta polimerizada com fontes de luz halógena e LED, em função da densidade de energia luminosa irradiada". Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/25/25131/tde-22102009-103040/.
Texto completoAt this study it was evaluated the microhardness of the Z250 (3M ESPE) resin composite, when light cured for different periods of time (s), with different power densities (mW/cm²), related to the irradiated luminous energy density (8 J/cm², 12 J/cm² and 16 J/cm²), in order to establish a minimal energy density capable of adequately polymerize the composites. One halogen light curing unit Degulux- Degussa, with 600 mW/cm² of power density and two light-emitting diodes curing units Ultraled XP (Dabi-Atlante) with 150 mW/cm² and LED Ultrablue-IS (DMC) with 300 mW/cm² and 600 mW/cm² were used. Two bipartite PTFE matrices, with 1 and 2 mm of depth and a central orifice of 5 mm diameter, were used to make 60 specimens, 5 per group. The halves of the matrix were positioned inside a brass ring with both depths to prepare the specimens. The resin composite was inserted and light-activated according to the different periods and energy densities of each lightcuring unit. To evaluate Knoop microhardness, specimens were taken to a microdurometer Shimadzu HMV-2 with a static load of 300 g for 5 seconds, evaluating both exposed to light (surface) and opposite to light (base) exposition surfaces, totalizing 120 measurements. Results were submitted to ANOVA and Tukeys test with 5% significance level. Based on the obtained results, it was concluded that, starting from 16 J/cm² and 12 J/cm² of energy luminous density, 2 mm depth resin composite can be adequately polymerized utilizing halogen (600 mW/cm²) and LED ( starting from 300 mW/cm²) curing-units respectively. However, additional clinical studies are necessary to complement this investigation.
Shaheen, Mohammed Mahmoud Zaki Mohammed. "Design and Assessment of Vertical Axis Wind Turbine Farms". University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1439306478.
Texto completoNatarajan, Hariharan. "Post occupancy energy analysis of the Gwinnett Environmental and Heritage Center". Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41214.
Texto completoFogleman, Myles. "Cold X-ray Effects on Satellite Solar Panels in Orbit". VCU Scholars Compass, 2019. https://scholarscompass.vcu.edu/etd/6065.
Texto completoHlongwa, Ntuthuko Wonderboy. "Thermochemical Storage and Lithium Ion Capacitors Efficiency of Manganese-Graphene Framework". University of the Western Cape, 2018. http://hdl.handle.net/11394/6458.
Texto completoLithium ion capacitors are new and promising class of energy storage devices formed from a combination of lithium-ion battery electrode materials with those of supercapacitors. They exhibit better electrochemical properties in terms of energy and power densities than the above mentioned storage systems. In this work, lithium manganese oxide spinel (LiMn2O4; LMO) and lithium manganese phosphate (LiMnPO4; LMP) as well as their respective nickel-doped graphenised derivatives (G-LMNO and G-LMNP) were synthesized and each cathode material used to fabricate lithium ion capacitors in an electrochemical assembly that utilised activated carbon (AC) as the negative electrode and lithium sulphate electrolyte in a two-electrode system. The synthetic protocol for the preparation of the materials followed a simple solvothermal route with subsequent calcination at 500 - 800 ?C. The morphological, structural and electrochemical properties of the as prepared materials were thoroughly investigated through various characterisation techniques involving High resolution scanning electron microscopy (HRSEM), High resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), Small-angle X-ray scattering (SAXS), Electrochemical impedance spectroscopy (EIS), Cyclic voltammetry (CV) and Galvanostatic charge/discharge.
2021-12-31
Jensen, Zachary R. "Improvements to the Two-Point In Situ Method for Measurement of the Room Constant and Sound Power in Semi-Reverberant Rooms". BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/5724.
Texto completoPEREIRA, SERGIO A. "Conceito alternativo de um reator hibrido (conjunto sub-critico acoplado com acelerador)". reponame:Repositório Institucional do IPEN, 2002. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10991.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
Ji, Xiaoyan. "Thermodynamic properties of humid air and their application in advanced power generation cycles". Doctoral thesis, Stockholm : Department of Chemical and Engineering and Technology, Royal Institute of Technology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4129.
Texto completoYouard, Timothy John. "Feasibility of an Electric Jetpack". Thesis, University of Canterbury. Electrical and Computer Engineering, 2010. http://hdl.handle.net/10092/5293.
Texto completoRAFIQUE, AMJID. "Flexible Fiber-Shaped Supercapacitor for Wearable Electronics". Doctoral thesis, Politecnico di Torino, 2019. http://hdl.handle.net/11583/2729354.
Texto completoMetchueng, Kamdem Syntia. "Stockage de chaleur dans l'habitat par sorption zéolite/H2O". Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI059/document.
Texto completoHeat storage systems for residential house heating could contribute to smoothing the load curve and would help prevent the use of the most polluting power plants or electricity imports during consumption peaks. Thermochemical heat storage systems are suitable for the intended application since they have high energy densities and low thermal losses. This thesis focuses on the design of an adsorption heat storage system that would be used to shed the load curve of the heating device of a house or residential district during the winter peak consumption periods. The zeolite/H2O pair, which has interesting features such as a high energy density and meets the conditions of safety required for a heat storage system for housing, is implemented in a modular fixed bed reactor. A 1D pseudo-homogeneous model was developed in order to simulate the performance of a fixed bed of zeolite during the adsorption and desorption of water. The latter was designed so as to facilitate the integration of data on new generations of materials and model couplings. The need to obtain data on the sorption properties of the zeolite/H2O pair to have reliable simulation results has been demonstrated, particularly at low partial pressures of water vapor and under the operating conditions selected. The experimental validation phase shows that the pseudo-homogeneous model provides a satisfactory estimate of criteria such as the autonomy, the responsiveness and the average power delivered during the discharging phase and the charging time. The model is thus a good sizing and management tool of the reactor. A sensitivity analysis, with the method of Morris, showed that improved model estimates require a more accurate assessment of the additional heat of sorption and porosity of the bed. After assessing the heating needs of the LEB house with a thermal model of the latter in cold climate conditions, two heat storage reactors were sized in order to shed the heating system's load curve either between 6 and 8pm or during the coldest week of the year. While the first strategy results in a more compact storage system, the second makes it possible to reduce the number of on/off cycles. The need for predictive control for monitoring the storage system was highlighted. As for the residential district of 50 LEB houses, diversity is considered when estimating the heating needs of the latter during the coldest week in Nancy. The heat source during the charging phase of the container would be industrial waste heat. During the coldest week, two sizings are suggested. For similar load shedding strategies, the comparison of the equivalent storage volume per house in the district with the storage volume for a single house serves highlights the importance of taking into account diversity. In order to meet the heating needs in Nancy, an equivalent volume of 544 liters per house in the district is sufficient whereas 580 liters are needed for a LEB house
Chester, Ryan T. "Error Sensor Strategies for Active Noise Control and Active Acoustic Equalization in a Free Field". Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2298.pdf.
Texto completoAyme, Fabien. "Développement d'une méthode énergétique pour l'évaluation expérimentale des flux acoustiques entrants dans les cavités d'avion". Phd thesis, Ecole Centrale de Lyon, 2013. http://tel.archives-ouvertes.fr/tel-00995861.
Texto completoNovell, Sara T. "Design of Structural Stand for High-Precision Optics Microscopy". DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2132.
Texto completoToni, Kotchikpa Arnaud. "Conception et intégration d'un convertisseur buck en technologie 28 nm CMOS orientée plateformes mobiles". Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI049.
Texto completoThis thesis work consists into the design of a 3 states buck converter targeting the improvement of dynamic regulation of microprocessors supplies. The topology of the converter is, at first, implemented in IBMCMOS 180 nm technology to validate the transient performances of the3 states regulator. The prototype in 180 nm, uses an input voltage of 3.6V and outputs a voltage in the range of 0.8V to 2V. Its response to load transients shows about 1% of undershoot and 2 % of overshoot, proving a good dynamic behavior for a simple structure compared to state of the art.The 3 states converter is then integrated in 28 nm CMOS HPM (technologymostly used for microprocessors desgn). The experimental results on the prototype confirm the performances in terms of energy and area savings, aswell as dynamic response. The chip delivers 0.5V to 1.2V from a 1.8V supply,and shows a 90% peak efficiency. The measurements of dynamic regulation show less than 5% of noise on the processor supply and 10 mV/ns outputvoltage switching for DVFS purpose
Kirichenko, E. y E. Belovol. "High-energy-density sugar biobattery". Thesis, Sumy State University, 2014. http://essuir.sumdu.edu.ua/handle/123456789/45213.
Texto completoBouchaala, Dhouha. "Investigation of Current Excitation for Personal Health and Biological Tissues Monitoring". Doctoral thesis, Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-204801.
Texto completoDie Bioimpedanzspektroskopie gewinnt aufgrund ihrer besonderen Eigenschaften als nicht-invasive, schonende Messmethode zunehmend an Bedeutung im biomedizinischen Bereich. Dabei ergeben sich besondere erausforderungen für den Entwurf der Stromquelle zur Realisierung eines stabilen und sicheren Anregungsstroms. Gefordert ist eine hohe Genauigkeit bis zu einem Maximalstrom von 0.5 mA in einem Frequenzbereich, der der β-Dispersion entspricht, von wenigen kHz bis hin zu 1 MHz. Die Stabilität muss bei variablen Lastimpedanzen im Bereich von 100 Ω bis 10 kΩ gewährleistet sein. Dafür muss die Stromquelle eine hohe Ausgangsimpedanz aufweisen. Diese Arbeit fokussiert auf den Entwurf von spannungsgesteuerten Stromquellen. Verschiedene Arten von Stromquellen wurden untersucht und verglichen. Der "Voltage-Modus-Ansatz" mit Masse-referenzierter Last hat sich als besser geeignet und stabiler für biomedizinische Messungen erwiesen. Die Tietze-Schaltung und diese Howland-Schaltung zeigen dabei die niedrigsten Fehler des Ausgangsstroms und die höchste Ausgangsimpedanz. Im direkten Vergleich besitzt die verbesserte Howland-Schaltung doch eine einfachere Struktur, höhere Genauigkeit und bessere Stabilität und wird daher gegenüber der Tietze-Schaltung bevorzugt. Um weitere Stabilitätsverbesserungen bei der Howland-Schaltung zu erreichen, werden zwei Maβnahmen vorgeschlagen. Zum einen werden kompensierte Operationsverstärker eingeführt und zum anderen wird der Einfluss von Streukapazitäten bei hohen Frequenzen minimiert indem die Verstärkung mit Kondensatoren kompensiert wird. Durch diese Maβnahmen wird eine Genauigkeit von 0.5% bei niedrigen Frequenzen und 0.9% bei 1 MHz ermöglicht. Mit dem neuen Entwurf der spannungsgesteuerten Stromquelle ist ein entscheidender Meilenstein für die Realisierung tragbarer Messsysteme der Bioimpedanz erreicht. Um eine kurze Messzeit zu realisieren wurde eine vergleichende Studie von Anregungssignalen und deren Signalparameter durchgeführt. Die Ergebnisse zeigen, dass binäre Chirp-Signale aufgrund der reduzierten Messzeit, des niedrigen Crest-Faktors unter 2.8 und hohe Energieeffizienz von mehr als 54% bei hohem Rauschlevel besonders geeignet sind. Simulationsergebnisse zeigen, dass die entwickelte Howland-Stromquelle zusammen mit einem binären Mehrfrequenzsignal den geringsten Amplitudenfehler im gesamten Frequenzbereich realisiert
Erices, Muñoz Eduardo Andrés y Rojas Cristian Patricio Torres. "Sun Power Energy". Tesis, Universidad de Chile, 2015. http://repositorio.uchile.cl/handle/2250/137206.
Texto completoEduardo Andres Erices Muñoz [Parte I Análisis estratégico y de mercado], Cristian Patricio Torres Rojas [Parte II Análisis organizativo-financiero]
Autores no autorizan el acceso a texto completo de su documento
La necesidad de aumentar la capacidad instalada de la matriz energética del país es un tema que en la última década se ha instalado en la agenda nacional, dado que el crecimiento económico de Chile implica un mayor consumo eléctrico. A su vez, la estrechez energética se ve representada con mayor profundidad en la industria de la minería, especialmente en el norte grande de Chile. El sector minero, además de ser el principal consumidor de energía eléctrica del país, ha experimentado desde el año 2000 una caída sostenida en su productividad, entre otros factores, por los mayores consumos y costos de la energía eléctrica, enfrentando actualmente uno de los precios más altos de América Latina1. Dado lo anterior, el Gobierno está asumiendo un rol más activo, definiendo una Agenda de Energía que incluye como uno de sus ejes el compromiso que un 45% de la capacidad eléctrica que se instalará en el país hasta el año 2025 sean energías renovables no convencionales (ERNC) y, de esta forma, cumplir con la meta de la Ley 20/25 de ingresar a la matriz energética un 20% de ERNC para dicho año. En este sentido, la energía fotovoltaica es una alternativa técnicamente viable para cubrir el consumo eléctrico, principalmente en el norte grande del país, dado que posee un importantísimo potencial solar. El propósito del presente plan de negocios es evaluar la factibilidad económica y financiera de ingresar al negocio de las energías renovables no convencionales, de una manera no convencional. Más allá de este juego de palabras, dado que la mayoría de los proyectos de generación de energía limpia se basan en el modelo de negocios tradicional, o sea generando e inyectando energía al sistema y transando los precios en el mercado spot, la oportunidad de negocio se visualiza en vender directamente la energía a la industria minera, sin intermediarios ni costos de transmisión relevantes. La industria eléctrica nacional está dividida en tres segmentos: generación, transmisión y distribución de energía eléctrica. Las actividades de transmisión y distribución tienen el carácter de monopolio natural. El sector de generación opera en condiciones de competencia, no obstante se caracteriza por ser un mercado altamente concentrado. Asimismo, existen cuatro sistemas eléctricos siendo los dos más importantes el SING (Sistema Interconectado del Norte Grande) y el SIC (Sistema Interconectado Central). La matriz energética del SING se alimenta en un 95% de fuentes térmicas (carbón, diésel, gas natural). En cuanto al desarrollo de proyectos ERNC, a pesar que el país posee condiciones naturales favorables para las energías solar y eólica, recién en el año 2014 se observó un “despegue” de las ERNC en Chile, materializándose proyectos con una capacidad instalada de casi 1.000 MW. Además, a nivel mundial la curva de aprendizaje en el costo de fabricación y operación de la tecnología solar fotovoltaica, ha permitido alcanzar precios competitivos respecto a las fuentes convencionales de energía. El mercado objetivo se concentra en el segmento de generación, a través del suministro eléctrico en base a energías renovables no convencionales, específicamente solar tipo fotovoltaica, para las empresas mineras (cobre) ubicadas en las regiones de Tarapacá y Antofagasta, ya que reúnen las condiciones de vida útil de la faena minera y disponibilidad de terrenos, de acuerdo a la propuesta de valor del proyecto. El modelo de negocios consiste en satisfacer parte de la demanda de energía eléctrica de las empresas mineras señaladas en el párrafo anterior, por medio de una planta solar fotovoltaica de 3 MW de potencia instalada y a través de un contrato de suministro tipo PPA (Power Purchase Agreement) a 20 años. La ventaja competitiva consiste en ofrecer una tarifa estable durante el período del contrato más baja que su tarifa actual en base a generación convencional, lo cual permitirá al cliente capturar y proyectar el ahorro en sus costos operativos. Además, la propuesta tiene la característica que la planta se construirá in-situ, aprovechando la superficie disponible en la faena minera, generando valor compartido en la economía de escala por el costo del terreno y línea de transmisión y conexión eléctrica. La operación y mantenimiento de la planta fotovoltaica estará a cargo de nuestra empresa. Para el desarrollo del negocio, dado que implica montos de inversión relevantes (USD 5,6 millones para cada planta) y se requiere de un respaldo tecnológico y logístico para realizar ese tipo de proyectos, se creará una Unidad Estratégica de Negocio (UEN) denominada “SUN POWER ENERGY” (SPE), bajo la estructura organizacional de E.CL S.A., una de las empresas principales que operan en el SING. Finalmente, en la evaluación financiera se contempla la ejecución de tres plantas solares dentro de los primeros seis años, con un total de aporte de capital requerido de USD 10 millones. Se ha considerado el apalancamiento financiero del proyecto, mediante la obtención de préstamos bancarios por USD 7,8 millones. Como resultado, través del valor actual de los flujos de caja libres descontados a una tasa del 7,5%, se obtiene un valor de la empresa sin deuda de USD 52.382, con una TIR del 7,5% y un periodo de recuperación de la inversión (payback) de 12 años. La TIR del inversionista alcanza al 7,9% con un VAN ajustado de USD 576.161.
Kim, Hyea. "High energy density direct methanol fuel cells". Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37106.
Texto completoKhorashad, Arash Sorouri. "Investigation of the exchange energy density functional". Thesis, Imperial College London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504765.
Texto completoOlsson, Robbie Stefan Ian. "High energy density physics in cluster media". Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/18394.
Texto completoXu, Buye. "Generalized Acoustic Energy Density and Its Applications". BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2339.
Texto completoShin, Il-Won. "POWER SPECTRAL DENSITY ANALYSIS OF PRINTER DEFECT". UKnowledge, 2005. http://uknowledge.uky.edu/gradschool_theses/266.
Texto completoChen, Zheng. "Electrical Integration of SiC Power Devices for High-Power-Density Applications". Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/23923.
Texto completoPh. D.
Nikonov, M. "Energy resources: wave power". Thesis, Sumy State University, 2017. http://essuir.sumdu.edu.ua/handle/123456789/62834.
Texto completo馮錦生 y Kam-sang Fung. "Fatigue crack propagation with strain energy density approach". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1989. http://hub.hku.hk/bib/B31209713.
Texto completoChung, Kang Ko. "Heteroatom-containing carbons for high energy density supercapacitor". Phd thesis, Universität Potsdam, 2013. http://opus.kobv.de/ubp/volltexte/2014/6982/.
Texto completoDer Superkondensator ist einer der wichtigsten Energiespeicher da seine Konstruktion die Lösung vieler Nachteile von Batterien erlaubt. Allerdings weisen derzeitige Systeme noch zu geringe Energiedichten auf. Um Superkondensatoren mit Energiedichten vergleichbar zu Batterien zu ermöglichen, wurden in der vorliegenden Dissertation neue, heteroatomhaltige Kohlenstoffe in Form von Partikeln und Filmen untersucht. Aufgrund geringer Kosten, hohen Ausbeuten, Polymerisierbarkeit usw. wurde die stickstoffhaltige Substanz Acrodam als Kohlenstoffvorstufe verwendet. Die Kohlenstoffpartikel wurden ausgehend von Acrodam zusammen mit Cäsiumacetat als schmelzbares Flussmittel hergestellt und wiesen ausgezeichnete Eigenschaften in Hydrochinon geladenen Schwefelsäure-Elektrolyten mit hohen Energiedichten (bis zu 133,0 Wh kg–1) und guten Zyklusstabilitäten auf. Diese Eigenschaften sind bereits jetzt vergleichbar mit denen von Batterien. Weiterhin wurden unter Verwendung von Acrodamoligomeren als Vorstufe und mit Hilfe der kostengünstigen Rotationsbeschichtung leitfähige, dreidimensionale Kohlenstofffilme hergestellt. Bei einer Karbonisierungstemperatur von 1000 °C konnten die Materialien als homogene, flache, Hohlraum-und Riss-freie Filme erhalten werden, die eine hohe Leitfähigkeit (bis zu 334 S cm–1) aufwiesen. Darüber hinaus konnte mit einem organischen Templat ein dreidimensionaler, poröser Kohlenstoff geformt werden. Dies zeigt das Potential der Filme für verschiedene Anwendungen wie Superkondensatorelektroden; die Abwesenheit von Übergangswiderständen im Netzwerk sollte zu einem effizienten Transport von Elektronen in der Elektrode beitragen. Die Ergebnisse dieser Dissertation werden neue Wege zur Verbesserung der Energiedichte von Superkondensatoren sowie weiteren Anwendungen eröffnen.
Guillaud, Mathilde. "Neutrino oscillations at very high energy/matter density". Thesis, KTH, Fysik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-292510.
Texto completoNeutrinooscillationer i materia kan studeras i olika regimer beroende på inkommande neutrinernas energi och densiteten hos det bakomliggande mediet. I detta examensarbete undersöker vi neutrinooscillationer i gränsen av tät materia och mycket hög energi (TeV-PeV-intervall), och tar hänsyn till den absorption av neutriner som då kan inträffa i sådant materia. Detta absorptionsfenomen är relevant för neutrino-teleskopmätningar av astrofysiska neutriner. Vi börjar med att kort påminna oss om neutrinooscillationer i vakuum och konstruktionen av PMNS-matrisen. Vi försätter sedan med beräkningar av neutrinooscillationer i tät materia. Vi undersöker noggrannheten i resulterande effektiva 2-neutrino-blandningsformlerna. De uppvisar en god noggrannhet i jordlika materieprofiler i vårt intervall av energier. Vi utvecklar beräkningarna av oscillationssannolikheterna i tät materia inklusive absorption genom laddad ström oelastisk spridning i båda två- och tresmaksfallen. Vi finner att astrofysiska neutriner i tät materia absorberas, vilket minskar betydligt flödena för varje smak, med en resonansabsorption av elektron-antineutrino omkring E_res\simeq 6.3PeV. Vi diskuterar sedan effekterna av neutrinoabsorption på jorden för neutrino-teleskopmätningar. Vi finner att sol- och månskuggning är inte problematisk för nuvarande teleskop och kunde vara en bra vinkelupplösningsindikator för kommande teeskop.
Fung, Kam-sang. "Fatigue crack propagation with strain energy density approach /". [Hong Kong] : University of Hong Kong, 1989. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12827204.
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