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Sharp, Zachary B., and William J. Rahmeyer. "Energy Losses in Cross Junctions." DigitalCommons@USU, 2009. https://digitalcommons.usu.edu/etd/256.
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Solving for energy losses in pipe junctions has been a focus of study for many years. Although pipe junctions and fittings are at times considered "minor losses" in relation to other energy losses in a pipe network, there are cases where disregarding such losses in flow calculations will lead to errors. To facilitate these calculations, energy loss coefficients (K-factors) are commonly used to obtain energy losses for elbows, tees, crosses, valves, and other pipe fittings. When accurate K-factors are used, the flow rate and corresponding energy at any location in a pipe network can be calculated. K-factors are well defined for most pipe junctions and fittings; however, the literature documents no complete listings of K-factors for crosses. This study was commissioned to determine the K-factors for a wide range of flow combinations in a single pipe cross and the results provide information previously unavailable to compute energy losses associated with crosses. To obtain the loss coefficients, experimental data were collected in which the flow distribution in each of the four cross legs was varied to quantify the influence of velocity and flow distribution on head loss. For each data point the appropriate K-factors were calculated, resulting in over one thousand experimental K-factors that can be used in the design and analysis of piping systems containing crosses.
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Eves, Brian John. "Scanning probe energy loss spectroscopy." Thesis, University of Birmingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251871.
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Jeong, Yu Seon, Minh Vu Luu, Mary Hall Reno, and Ina Sarcevic. "Tau energy loss and ultrahigh energy skimming tau neutrinos." AMER PHYSICAL SOC, 2017. http://hdl.handle.net/10150/625525.
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We consider propagation of high-energy earth-skimming taus produced in interactions of astrophysical tau neutrinos. For astrophysical tau neutrinos, we take generic power-law flux, E-2 and the cosmogenic flux initiated by the protons. We calculate tau energy loss in several approaches, such as dipole models and the phenomenological approach in which parametrization of the F-2 is used. We evaluate the tau neutrino charged-current cross section using the same approaches for consistency. We find that uncertainty in the neutrino cross section and in the tau energy loss partially compensate giving very small theoretical uncertainty in the emerging tau flux for distances ranging from 2 to 100 km and for the energy range between 10(6) and 10(11) GeV, focusing on energies above 10(8) GeV. When we consider uncertainties in the neutrino cross section, inelasticity in neutrino interactions and the tau energy loss, which are not correlated, i.e. they are not all calculated in the same approach, theoretical uncertainty ranges from about 30% and 60% at 10(8) GeV to about factors of 3.3 and 3.8 at 10(11) GeV for the E-2 flux and the cosmogenic flux, respectively, for the distance of 10 km rock. The spread in predictions significantly increases for much larger distances, e.g., similar to 1, 000 km. Most of the uncertainty comes from the treatment of photonuclear interactions of the tau in transit through large distances. We also consider Monte Carlo calculation of the tau propagation and we find that the result for the emerging tau flux is in agreement with the result obtained using analytic approach. Our results are relevant to several experiments that are looking for skimming astrophysical taus, such as the Pierre Auger Observatory, HAWC and Ashra. We evaluate the aperture for the Auger and discuss briefly application to the other two experiments.
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Lundanes, Ingvild Olsen. "The propagation and energy losses of ultra high energy cosmic rays." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for fysikk, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-12654.
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This project investigates the propagation of ultra-high energy cosmic raynuclei and protons. A simulation of the propagation subjecting the particlesto energy losses due to cosmological redshift as well as interactions with theextra-galactic background radiation seeks to find the initial conditions at thesource which give the best results on Earth compared to the observations ofthe Pierre Auger Observatory (PAO).The results agree with previous works of the same kind that a chemicalcomposition of medium-weight fits the observed air shower data best. Thestarting conditions which gave the best results for the air shower characteristics
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Peña, Manchón Francisco Javier de la. "Advanced methods for Electron Energy Loss Spectroscopy core-loss analysis." Paris 11, 2010. http://www.theses.fr/2010PA112379.
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Les microscopes électroniques en transmission modernes sont capables de fournir une grande quantité d'informations sous la forme de jeux de données multi-dimensionnelles. Bien que les procédures développées pour l'analyse des spectres uniques soient utilisables pour le traitement de ces données, le développement de techniques plus avancées est indispensable pour une exploitation optimale de ces informations hautement redondantes. Dans ce contexte, nous avons exploré des alternatives aux méthodes standard de quantification, et cherché à optimiser les acquisitions expérimentales afin d'améliorer la précision des analyses. Cela constitue une réponse aux défis actuels de la spectroscopie de perte d'énergie d'électrons (EELS) dont les facteurs limitants sont souvent liés aux dégâts d'irradiation et à la contamination. La quantification élémentaire par la méthode standard d'intégration est limitée aux cas simples. Nous avons montré que l'utilisation d'une méthode basée sur l'ajustement des courbes expérimentales peut surmonter la plupart des limitations de la méthode standard. Cette nouvelle méthode nous a non seulement permis d'obtenir des cartographies élémentaires mais aussi les premières cartographies des liaisons chimiques à l'échelle nanométrique. Les méthodes quantitatives exigent de connaître à priori la composition de l'échantillon, ce qui constitue une difficulté majeur lors de l'analyse d'échantillons inconnus. Nous avons montré que les méthodes de séparation aveugle des sources permettent une analyse rapide et efficace des données multi-dimensionnelles, sans nécessiter la définition d'un modèle. En conditions optimales, il est ainsi possible d'extraire à partir des données expérimentales les signaux correspondants aux différents constituants chimiques ainsi que leur distribution dans l'échantillonModern analytical transmission electron microscopes are able to gather a large amount of information from the sample in the form of multi-dimensional datasets. Although the analytical procedures developed for single spectra can be extended to the analysis of multi-dimensional datasets, for an optimal use of this highly redundant information, more advanced techniques must be deployed. In this context, we investigate alternatives to the standard quantification methods and seek to optimise the experimental acquisition for accurate analysis. This addresses the current challenges facing the electron energy-loss spectroscopy (EELS) community, for whom beam damage and contamination are often the limiting factors. EELS elemental quantification by the standard integration method is limited to well-behaved cases. As an alternative we use curve fitting which, as we show, can overcome most of the limitations of the standard method. Furthermore, we extend the method to obtain, in addition to elemental maps, the first bonding maps at the nanoscale. A major difficulty when analysing multi-dimensional datasets of samples of unknown composition is that the quantitative methods require as an input the composition of the sample. We show that blind source separation methods enable fast and accurate analysis of multi-dimensional datasets without defining a model. In optimal conditions these methods are capable of extracting signals from the dataset corresponding to the different chemical compounds in the sample and their distribution
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Pickard, Christopher James. "Ab initio electron energy loss spectroscopy." Thesis, University of Cambridge, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627420.
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Chandorkar, Saurabh Arun. "Energy loss mechanisms in micromechanical resonators /." May be available electronically:, 2009. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Eljarrat, Ascunce Alberto. "Quantitative methods for electron energy loss spectroscopy." Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/349214.
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This thesis explores the analytical capabilities of low-loss electron energy loss spectroscopy (EELS), applied to disentangle the intimate configuration of advanced semiconductor heterostructures. Modern aberration corrected scanning transmission electron microscopy (STEM) allows extracting spectroscopic information from extremely constrained areas, down to atomic resolution. Because of this, EELS is becoming increasingly popular for the examination of novel semiconductor devices, as the characteristic size of their constituent structures shrinks. Energy-loss spectra contain a high amount of information, and since the electron beam undergoes well-known inelastic scattering processes, we can trace the features in these spectra down to elementary excitations in the atomic electronic configuration.
In Chapter 1, the general theoretical framework for low-loss EELS is described. This formulation, the dielectric model of inelastic scattering, takes into account the electrodynamic properties of the fast electron beam and the quantum mechanical description of the materials. Low-loss EELS features are originated both from collective mode (plasmons) and single electron excitations (e.g. band gap), that contain relevant chemical and structural information. The nature of these excitations and the inelastic processes involved has to be taken into account in order to analyze experimental data or to perform simulations. The computational tools required to perform these tasks are presented in Chapter 2. Among them, calibration, deconvolution and Kramers-Kronig analysis (KKA) of the spectrum constitute the most relevant procedures, that ultimately help obtain the dielectric information in the form of a complex dielectric function (CDF). This information may be then compared to the one obtained by optical techniques or with the results from simulations. Additional techniques are explained, focusing first on multivariate analysis (MVA) algorithms that exploit the hyperspectral acquisition of EELS, i.e. spectrum imaging (SI) modes. Finally, an introduction to the density functional theory (DFT) simulations of the energy-loss spectrum is given.
In Chapter 3, DFT simulations concerning (Al, Ga, In)N binary and ternary compounds are introduced. The prediction of properties observed in low-loss EELS of these semiconductor materials, such as the band gap energy, is improved in these calculations. Moreover, a super-cell approach allows to obtain the composition dependence of both band gap and plasmon energies from the theoretical dielectric response coefficients of ternary alloys. These results are exploited in the two following chapters, in which we experimentally probe structures based on group-III nitride binary and ternary compounds. In Chapter 4, two distributed Bragg reflector structures are examined (based upon AlN/GaN and InAlN/GaN multilayers, respectively) through different strategies for the characterization of composition from plasmon energy shift. Moreover; HAADF image simulation is used to corroborate he obtained results; plasmon width, band gap energy and other features are measured; and, KKA is performed to obtain the CDF of GaN. In Chapter 5, a multiple InGaN quantum well (QW) structure is examined. In these QWs (indium rich layers of a few nanometers in width), we carry out an analysis of the energy-loss spectrum taking into account delocalization and quantum confinement effects. We propose useful alternatives complementary to the study of plasmon energy, using KKA of the spectrum.
Chapters 6 and 7 deal with the analysis of structures that present pure silicon-nanocrystals (Si-NCs) embedded in silicon-based dielectric matrices. Our aim is to study the properties of these nanoparticles individually, but the measured low-loss spectrum always contains mixed signatures from the embedding matrix as well. In this scenario, Chapter 6 proposes the most straightforward solution; using a model-based fit that contains two peaks. Using this strategy, the Si-NCs embedded in an Er-doped SiO2 layer are characterized. Another strategy, presented in Chapter 7, uses computer-vision tools and MVA algorithms in low-loss EELS-SIs to separate the signature spectra of the Si-NCs. The advantages and drawbacks of this technique are revealed through its application to three different matrices (SiO2, Si3N4 and SiC). Moreover, the application of KKA to the MVA results is demonstrated, which allows to extract CDFs for the Si-NCs and surrounding matrices.Este trabajo explora las posibilidades analíticas que ofrece la técnica de espectroscopia electrónica de bajas pérdidas (low-loss EELS), capaces de revelar la configuración estructural de los más avanzados dispositivos semiconductores. El uso de modernos microscopios electrónicos de transmisión-barrido (STEM) nos permite obtener información espectroscópica a partir de volúmenes reducidos, hasta llegar a resolución atómica. Por ello, EELS es cada vez mas popular para la observación de los dispositivos semiconductores, a medida que los tamaños característicos de sus estructuras constituyentes se miniaturiza. Los espectros de pérdida de energía contienen mucha información: dado que el haz de electrones sufre unos bien conocidos procesos de dispersión inelástica, podemos trazar relaciones entre estos espectros y excitaciones elementales en la configuración atómica de los elementos y compuestos constituyentes de cada material. Se describe un marco teórico para el estudio del low-loss EELS: el modelo dieléctrico de dispersión inelástica, que toma en consideración las propiedades electrodinámicas del haz de electrones y la descripción mecano-cuántica de los materiales. Adicionalmente, se describen en detalle las herramientas utilizadas en el análisis de datos experimentales o la simulación teórica de espectros. Monitorizando las energías de band gap y plasmon en los datos experimentales de low-loss EELS se obtiene información directa sobre propiedades electrónicas de los materiales. Además, usando análisis Kramers-Kronig en los espectros se obtiene información dieléctrica que puede ser comparada con las simulaciones o con otras técnicas (ópticas). Se demuestra el uso de estas herramientas con una serie de estudios sobre estructuras basadas en nitruros del grupo-III. Por otro lado, el uso de algoritmos para el análisis multivariante permite separar las contribuciones individuales que se miden mezcladas en espectros de estructuras complicadas. Hemos utilizado estas avanzadas herramientas para el análisis de estructuras basadas en silicio que contienen nano-cristales embebidos en matrices dieléctricas.
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Nicholls, Rebecca Jane. "Electron energy loss spectroscopy of fullerene materials." Thesis, University of Oxford, 2006. http://ora.ox.ac.uk/objects/uuid:2fd55ddf-ca30-4b9a-a37f-61b024a3f22f.
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This thesis is comprised of two closely related studies of fullerenes. The first part is an investigation of C60 and C70 nanocrystals using both experimental and simulated electron energy loss (EEL) spectra. Through a detailed comparison of particular features in EEL spectra collected from these materials in a transmission electron microscope, with simulated spectra, it is established that differences in spectra from different materials can be linked to particular aspects of the structural models. For example, in the case of C60 differences in experimental spectra from different samples can be linked to differences in the bond lengths within the molecules of different samples. In the case of C70, it is found that features within the spectrum which have previously been attributed to the ten equatorial atoms do not have this origin in a crystal. The second part is an experimental investigation of endohedral fullerenes Nd@C82 and Sc3N@C80. The effect of temperature on the EEL spectrum is investigated and, in the case of Nd@C82, the effect of the presence of different isomers is also investigated. Spectra are successfully obtained from the encapsulated atoms, and the importance of careful experiments in terms of avoiding contamination is highlighted.
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Natusch, Michael Kurt Heinrich. "Detection limits in electron energy-loss spectroscopy." Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624128.
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Millar, Carol Evelyn. "Energy gains and losses in Be star envelopes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ58153.pdf.
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Claesson, Gabriel. "Evaluation of Energy Losses in a Wind Farm." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-293053.
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In recent years, the power production from wind power and other renewable energy sources has increased significantly. Arguably, this is due to the greenhouse effect and the economic benefit of generating power from the wind. Wind power has the potential to replace other non-renewable power sources. Thus, it is of interest to maximize the efficiency of the wind farms, to produce the most power to the grid. This implies that the power losses within the wind farms needs to be minimized. Evidently, there are expected and unavoidable power losses within the wind farm. However, when there are unexpected power losses or the power losses exceed what is expected, the question arises as to what the reason for this is and if it is possible to avoid or decrease these power losses. In this thesis, a case study is conducted in collaboration with Skellefteå Kraft. An existing wind farm is studied, as the case company noted inconsistencies in power losses. One section has a larger share of power losses than the other section in the wind farm. Thus, it is of interest to the case company to find out why this is, to find the source to these power losses, as unnecessary power losses mean a loss of profit as well as loss of useful power produced from renewable energy sources. This suggests that if the sources of the power losses are identified and the power losses are deemed unnecessary for the operation of the wind farm, the case company can take actions accordingly. Hence, this thesis aims to identify the sources of the power losses and to create basis to whether these power losses are justified and necessary for the operation of the existing wind farm or not. To study the power losses in the existing wind farm, a model is developed utilizing load flow analysis. The load flow analysis is based on real hour power production data of the year of 2019. Thus, several load flow calculations are carried out to modify the system parameters to optimize the accuracy, and to verify the model. The model is then used to estimate and evaluate the power losses within the wind farm, and for identification of the sources of the power losses. The results of the case study prove that a rather accurate model was successfully developed. The model indicates that, for the year of 2019, the difference in power losses between the two sections of the wind farm was primarily due to the de-icing systems. The de-icing system of one section constituted for a significantly larger share of the power losses in that section than what the de-icing system of the other section constituted for the power losses in the other section. This suggests that the de-icing system needs to be evaluated further. Due to the design of the wind farm, there is an additional transformer in one of the sections. Through utilizing the model, the power losses of the additional transformer were estimated. For the year of 2019, the model indicated that the power losses of the additional transformer contributed rather insignificantly to the difference in power losses between the two sections.Under de senaste åren har kraftproduktionen från vindkraft och andra förnybara energikällor ökat avsevärt. Det beror bland annat på växthus- effekten och de ekonomiska fördelarna med att generera el från vindkraft. Vindkraften har potential att ersätta andra icke förnybara energikällor. Därför är det av intresse att maximera vindkraftparkernas effektivitet och maximera den genererade effekten ut på elnätet. Detta innebär att effektförlusterna inom vindkraftsparkerna bör minimeras. Det finns förväntade och oundvikliga kraftförluster inom vindkraftsparken. När det uppstår oväntade effektförluster eller effektförlusterna överstiger det som förväntas, blir frågan om vad orsaken är och om det är möjligt att undvika alternativt minska på dessa effektförluster. I detta arbete genomförs en fallstudie i samarbete med Skellefteå Kraft. En befintlig vindkraftspark studeras, eftersom företaget har noterat oväntade effektförluster. En sektion har större andel effektförluster jämfört med den andra delen av vindkraftsparken. Därför är det av intresse för företaget att ta reda på anledningen till detta, eftersom onödiga effektförluster innebär ekonomiska och effektmässiga förluster. Det betyder att om källorna till effektförlusterna identifieras och är onödiga för driften av vindkraftsparken kan företaget vidta åtgärder därefter. Syftet med detta arbete är därför att identifiera källorna av effektförlusterna och identifiera om dessa effektförluster är nödvändiga för driften av vindkraftsparken eller inte. För att studera effektförlusterna i den befintliga vindkraftsparken utvecklas en modell med hjälp av lastflödesanalys. Lastflödesanalysen är baserad på realtidsdata för kraftproduktion under år 2019. Således utförs flera lastflödesberäkningar för att modifiera modellens systemparametrar, för att öka noggrannheten och för att verifiera modellen. Modellen används sedan för att uppskatta och utvärdera effektförlusterna inom vindkraftsparken och för identifiering av källorna till effektförlusterna. Resultaten från studien visar att en noggrann modell kunde utvecklas. Modellen indikerar att skillnaden i effektförluster mellan de två sektionerna i vindkraftparken för år 2019 främst berodde främst på avisningssystemen. Avisningssystemet i den ena sektionen utgjorde en betydligt större andel av effektförlusterna än i den andra sektionen. Detta tyder på att avisningssystemet bör utvärderas ytterligare. På grund av vindkraftsparkens utformning finns det en extra transformator i en av sektionerna. För år 2019 indikerade modellen att effektförlusterna för den extra transformatorn knappt bidrog till skillnaderna i effektförluster mellan de två sektionerna.
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Clarke, Ralph Henry. "Heat losses in internal combustion engines." Master's thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/8290.
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Bibliography: leaves 119-121.This thesis deals with the effects of cooling and heat losses in internal combustion engines. The object of this work was to examine and research various cooling concepts and methods to reduce heat loss to engine coolant, improve thermal efficiency and to predict heat transfer values for these alternatives. The optimum system to be considered for possible application to small rural stationary engines. A literature survey was undertaken, covering work performed in the field of internal combustion engine cooling. Besides the conventional cooling system, two concepts emerged for consideration. These were the precision cooling system and the new heat pipe concept, the latter being relatively unknown for internal combustion cooling application. The precision cooling system, consists of a series of small bore tubes conducting coolant only to the critical areas of an engine. The theory being that in the conventional systems many regions are overcooled, resulting in excessive heat loss. The heat pipe is a device of very high thermal conductance and normally consists of a sealed tube containing a small quantity of fluid. Under operating conditions the tubular container becomes an evaporator region in the heat input area and a condenser region in the heat-out area. It is therefore basically a thermal flux transformer,attached to the object to be cooled. The heat pipe performance is also capable of being modulated by varying its system pressure. This is a positive feature for internal combustion engine application in controlling detonation and NOx emissions. Various facts were obtained from the literature survey and considered in the theoretical review. These facts were extended into models, predicting the heat transfer performance of each concept in terms of coolant heat outflow and heat transfer coefficients. The experimental apparatus was based on an automotive cylinder head with heated oil passing through the combustion chamber and exhaust port to simulate combustion gases. Experiments were conducted on this apparatus to validate the predicted theoretical performance of the three concepts. Tests were also made to observe the effect of heat pipe modulation and nucleate boiling in the precision system. Concept theory was validated as shown by the experimental and test results. The performance for each system approximated the predicted heat transfer and heat loss values. By comparison of the heat input, coolant heat outflow values and heat transfer coefficients it was found that the precision system was the most efficient, followed by the heat pipe and the conventional system being the least efficient. It was concluded that the heat loss tests provided a valuable insight into the heat transfer phenomenon as applied to the three systems investigated. This work also illustrated the effects of the variation of coolant flow, velocity and influence of nucleate boiling. This thesis has shown the potential of the systems tested, for controlling heat losses in internal combustion engines. The research work has created a data base for further in-depth evaluation and development of the heat pipe and the precision cooling system. Based on the findings of the experimental work done on this project, several commercial applications exist for the heat pipe and precision cooling systems. Further in-depth research is recommended to extend their potential in the automotive industry.
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Balthazar, Edward John. "Residential building energy consumption and loss reduction methods." [Huntington, WV : Marshall University Libraries], 2008. http://www.marshall.edu/etd/descript.asp?ref=864.
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Thesis (M.S.)--Marshall University, 2008.Title from document title page. Includes abstract. Document formatted into pages: contains ix, 94 p. : ill. Includes bibliographical references (p. 90-91).
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Yuan, Jun. "Electron energy loss and cathodoluminescence of rare earths." Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.256453.
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Walls, Michael Gerard. "Electron energy-loss spectroscopy of surfaces and interfaces." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254503.
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Drummond-Brydson, Richard. "Electron energy loss spectroscopy in solid-state chemistry." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.237906.
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Wilkins, A. C. R. "Translational energy loss studies of electron capture reactions." Thesis, Swansea University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636601.
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Translational energy spectroscopy is an invaluable tool in the study of ion-neutral processes. By measuring the change in energy of the projectile ion information can be obtained about the initial and final states of the projectile and the final states of the target (presuming that the target possesses only thermal energy and is initially in its ground state) for a wide range of collisional processes. One such process is that of electron capture where the multiply-charged ion will capture one or more electrons from the target. The Wigner spin-conservation rule has previously been studied for binary collision processes, however the applicability to electron capture reactions has not been studied extensively. Over eighty reaction channels for the single-electron capture by N2+, O2+, C2+ and Ar4+ have been identified, all of which conform with the rule. Of equal significance the spin non-conserved channels which lie in the same energy range are conspicuously absent. With the O2+ and Ar4+ collision systems a rare quintet state is also identified in the primary ion beam. The spin rule appears less stringent for double-electron capture reactions where many spin forbidden reaction channels have been identified. These are explained as being allowed through two consecutive spin-conserved single electron capture channels. The importance of the design of the collision cell is often overlooked in a spectrometer. Two novel collision cells have been constructed; the first, a thin collision cell, was utilised to assess and reduce the collisional broadening aberration in a translational energy loss spectrum. A second larger cell was designed to attenuate the ion beam to a high degree so that the metastable content of an ion beam can be measured using the ion beam attenuation method. Metastable ions play a substantial part in many collisional phenomena and these measurements are used to quantify the previously obtained electron-capture spectra.
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Eustace, David Andrew. "Spin polarisation effects in electron energy loss spectroscopy." Thesis, University of Glasgow, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438978.
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Muellejans, Harald. "Secondary electron emission in coincidence with primary energy losses." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240071.
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Молошний, Олександр Миколайович, Александр Николаевич Молошный, and Oleksandr Mykolaiovych Moloshnyi. "Comparison of energy losses in designs of hermetic pumps." Thesis, Sumy State University, 2016. http://essuir.sumdu.edu.ua/handle/123456789/46937.
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Modern chemical and oil production is characterized by stringent
environmental regulations. Most of the equipment in the technological cycle
must be hermetic. Serious problem is the energy efficiency of equipment.
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Crespo, Raul Jose. "Evaluation of energy usage in the chemical industry and effective measures to reduce energy losses." Master's thesis, Mississippi State : Mississippi State University, 2009. http://library.msstate.edu/etd/show.asp?etd=etd-04022009-173317.
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Byrne, Ciaran Martin. "Energy loss and charge transfer effects of low energy protons in thin organic films." Thesis, Queen Mary, University of London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393732.
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Gass, Mhairi Hope. "Low-loss electron energy loss spectroscopy in a scanning transmission electron microscope of GaInNAs." Thesis, University of Liverpool, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.415656.
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Bartsch, Detlef. "Energy loss measurement with the ZEUS Central Tracking Detector." [S.l.] : [s.n.], 2007. http://deposit.ddb.de/cgi-bin/dokserv?idn=985183535.
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McNeil, Kirsten Elizabeth. "Energy loss characterization of the P3 MEMS heat engine." Online access for everyone, 2006. http://www.dissertations.wsu.edu/Thesis/Summer2006/k%5Fmcneil%5F062906.pdf.
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McComb, David William. "An electron energy-loss spectroscopy investigation of zeolite dealumination." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359404.
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Kulikowski, Anoushka. "Phonon studies of energy loss in vertical tunnelling structures." Thesis, Lancaster University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286990.
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Protheroe, A. R. "Electron energy loss spectroscopy of some alkaline earth oxides." Thesis, University of York, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377302.
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Bauer, Karl. "Scanning probe energy loss spectroscopy (SPELS) of structured surfaces." Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/6103/.
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In scanning probe energy loss spectroscopy (SPELS) an STM tip is used as a localised source of field emitted electrons by applying a high voltage. Energy loss measurements of the backscattered electrons provide spectroscopic information from the sample. The energy resolution is ≈0.3eV. In principle, a raster scan provides a spatially resolved image of these excitations. In this work, a new generation instrument is employed and developed in which the electrons are captured by an electrostatic lens system and focussed onto a multichannel detector using a 127° cylindrical-sector analyser. Additionally, a compact retarding field analyser has been built, which can be placed within 20mm of the tip position. Both detectors have been positioned at an angle of 7° to the surface plane, as most of the backscattered electrons are expected to emerge near the surface plane due to the high electric field between tip and sample. Ag and Au nanostructures on graphite designed for the SPELS instrument covering a large sample area have been prepared by electron beam lithography. The characteristics of the instrument have been measured, with high spatial resolution (down to 25nm) images showing various contrast mechanisms. Spatially resolved silver surface plasmon maps are presented.
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Pališaitis, Justinas. "Valence Electron Energy Loss Spectroscopy of III-Nitride Semiconductors." Doctoral thesis, Linköpings universitet, Tunnfilmsfysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-85907.
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This doctorate thesis covers both experimental and theoretical investigations of the optical responses of the group III-nitrides (AlN, GaN, InN) and their ternary alloys. The goal of this research has been to explore the usefulness of valence electron energy loss spectroscopy (VEELS) for materials characterization of group III-nitride semiconductors at the nanoscale. The experiments are based on the evaluation of the bulk plasmon characteristics in the low energy loss part of the EEL spectrum since it is highly dependent on the material’s composition and strain. This method offers advantages as being fast, reliable, and sensitive. VEELS characterization results were corroborated with other experimental methods like X-ray diffraction and Rutherford backscattering spectrometry as well as full-potential calculations (Wien2k). Investigated III-nitride structures were grown using magnetron sputtering epitaxy and metal organic chemical vapor deposition techniques. Initially, it was demonstrated that EELS in the valence region is a powerful method for a fast compositional analysis of the Al1-xInxN (0≤x≤1) system. The bulk plasmon energy follows a linear relation with respect to the lattice parameter and composition in Al1-xInxN layers. Furthermore, the effect of strain on valence EELS was investigated. It was experimentally determined that the AlN bulk plasmon peak experiences a shift of 0.156 eV per 1% volume change at constant composition. The experimental results were corroborated by full-potential calculations, which showed that the bulk plasmon peak position varies nearly linearly with the unit-cell volume, at least up to 3% volume change. Employing the bulk plasmon energy loss, compositional characterization was also applied to confined structures, such as nanorods and quantum wells (QWs). Compositional profiling of spontaneously formed AlInN nanorods with varying In concentration was realized in cross-sectional and plan-view geometries. It was established that the structures exhibit a core-shell structure, where the In concentration in the core is higher than in the shell. The growth of InGaN/GaN multiple QWs with respect to composition and interface homogeneities was investigated. It was found that at certain compositions and thicknesses of QWs, where phase separation does not occur due to spinodal decomposition. Instead, QWs develop quantum dot like features inside the well as a consequence of Stranski-Krastanov-type growth mode, and delayed In incorporation into the structure. The thermal stability and degradation mechanisms of Al1-xInxN (0≤x≤1) films with different In contents, stacked in a multilayer sample, and different periodicity Al1-xInxN/AlN multilayer films, was investigated by performing a thermal annealing in combination with VEELS mapping in-situ. It was concluded that the In content in the Al1-xInxN layer determines the thermal stability and decomposition path. Finally, the phase separation by spinodal decomposition of different periodicity AlInN/AlN layers, with a starting composition inside the miscibility gap, was explored.
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Lawson, Laté Ayao. "Essays on economic growth energy use and biodiversity loss." Electronic Thesis or Diss., Strasbourg, 2019. http://www.theses.fr/2019STRAB011.
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L'impact de l'activité économique et de l'augmentation de la population sur l'environnement soulève de profondes questions sur l'avenir des sociétés humaines et des ressources environnementales. En ceci, les "Limites de la Croissance" ("Limits to Growth", Meadows, Meadows, Behrens et Randers, 1974) mettent en garde les sociétés humaines contre la possibilité d'un effondrement social si les tendances actuelles d'exploitation de ressources naturelles et de dégradation de l'environnement suivent leur court. La richesse de la nature étant primordiale à la richesse des nations, cette thèse en sciences économiques au travers de quatre contributions théoriques et empiriques traite de la possibilité d'une cohabitation pacifique des sociétés humaines avec la nature et discute des politiques de conservation de la nature. Nos résultats théoriques et empiriques montrent d'une part que l'expansion de l'habitat humain se fait au détriment des autres espèces biologiques (animales et végétales). D'autre part, nous montrons que les efforts actuels de conservation des espèces biologiques sont fortement orientés vers des forets dont la richesse en biodiversité s'avère douteuse. Finalement, nous montrons qu'une utilisation de plus en plus croissante des énergies primaires, donc à forts impacts écologiques, est encore à attendre des pays en développement. En termes de politiques environnementales, nos travaux appellent davantage à la réduction de l'empreinte écologique des sociétés humaines. Ceci inclut : Une exploitation favorisant la régénération des forêts et non la réduction des aires déjà couvertes ; L'élargissement des aires protégées surtout dans les pays en développement ; Une incitation des individus à orienter les préférences vers la demande de biens à faibles empreintes écologiquesThe impact of economic activities and increasing population on the environment raise profound interrogations towards the future of human societies and environmental resources. In this, the "Limits to Growth" (Meadows, Meadows, Behrens and Randers, 1974) warn human societies about the possibility of social collapse if current trends of exploitation of natural resources and environmental degradation remain unchanged. The wealth of nature being essential to the wealth of nations, this thesis in economics through four theoretical and empirical contributions addresses the possibility of a peaceful cohabitation between human and nature and discusses conservation policies of nature. Our theoretical and empirical results show on the one hand that human habitat is being expanded to the detriment of other biological species (animal and plant). On the other hand, we show that current efforts to conserve biological species are strongly oriented towards forests whose richness in biodiversity is doubtful. Finally, we show that an increasingly growing consumption of primary energies, therefore with strong ecological impacts, is still to be expected from developing countries. In terms of environmental policies, our work advocates for a reduction of the ecological footprint of human societies. This includes policies promoting forest regeneration and not the reduction of covered areas, expansion of protected areas, especially in developing countries and incentives for individuals to orient preferences towards the demand for goods with low ecological impacts
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Dick, Andrew Reid. "Switching performance and energy losses in fast plasma closing switches." Thesis, University of Strathclyde, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405482.
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Sui, Chen. "ENERGY AUDIT of GEFLE VAPEN." Thesis, University of Gävle, Ämnesavdelningen för energi- och maskinteknik, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-6538.
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The energy audit is a very interesting and complex work. The building energy audit is defined as a process to evaluate where the energy used in the building structure and to identify the opportunities of reduce energy consumptions. In this paper, it is a first time detailed study of energy audit for me. In this research, the object is to find is it necessary to improve the ventilation systems. So the first step is to estimate how much energy consumed in the building and to find out the saving potential.The major mission in this thesis is that to make a basic energy audit which is include the heat losses from the building and the heat supply in the building. The major heat losses are transmission losses, ventilation losses, heat losses from hot tap water and infiltration losses. In this project the first three types of heat losses could be find out by some useful methods but the infiltration losses is hard to measure. On the other side, the heat supply are composed by district heating , free heating from people inside, free heating from electricity applications and sun irradiation.To make an accurate and complete energy audit is essential for finding out where the energy consumption could be reduced. And this is what I am going to do in this thesis work.
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Raut, Prasad S. "Towards Development Of Polymeric Compounds For Energy Storage Devices And For Low Energy Loss Tires." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1493947416353888.
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Signorello, Concetta. "Reduction of Switching Losses in IGBT Power Modules." Doctoral thesis, Università di Catania, 2015. http://hdl.handle.net/10761/4056.
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The purpose of this work is to study in deep the transition phenomena of IGBTs in order to evaluate different optimization strategies for losses reduction and propose a novel technique.
In power applications a particular attention must be taken to such phenomena as commutation losses, overcurrents during the turn-ON and overvoltage at the turn-OFF of the devices.
These phenomena are connected to non ideal behavior of real devices and stray circuit parameters. Steep profiles of current lead to large ElectroMagnetic Interference (EMI) and overvoltages, while rapid variations of the voltage can produce phenomena of "latch-up" in single IGBT or unwanted commutations. On the other hand, slow commutations are characterized by low values of dv/dt and di/dt, causing excessive losses in those power application during commutations. Therefore, it is essential to face the issue with opposite requirements at the design stage obtaining optimal tradeoff.
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Muto, Shunsuke, and Yusuke Sasano. "Energy-drift correction of electron energy-loss spectra from prolonged data accumulation of low SNR signals." Oxford University Press, 2008. http://hdl.handle.net/2237/20779.
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Ruddick-Collins, Leonie C. "Establishing the benefits of protein intake during energy balance and energy restriction to improve weight loss." Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/114003/1/Leonie_Ruddick-Collins_Thesis.pdf.
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This thesis examined the effects of dietary protein manipulation during energy balance and energy restriction on physiological and behavioural mechanisms influencing body weight. Changes in protein intake were imposed to assess the role of dietary protein in maintaining whole body protein turnover, resting and postprandial energy expenditure, appetite and food preferences. Methodological issues such as reliability and the definition of weight stability were also addressed. The results from this thesis support higher dietary protein intakes as a means for maintaining protein turnover and resting energy expenditure during energy restriction.
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Estradé, Albiol Sònia. "Electron Energy Loss Spectroscopy Solutions for Nanoscale Materials Science Problems." Doctoral thesis, Universitat de Barcelona, 2009. http://hdl.handle.net/10803/662847.
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In the Transmission Electron Microscope (TEM), an incident electron suffers both elastic and inelastic scattering by the solid state thin sample that is being characterised. In the event of inelastic scattering, the incident electron gives a part of its energy to the electrons in the sample. The amount of lost energy can then be measured by a magnetic filter at the end of the column, and a plot displaying how many electrons have lost what amount of energy will give us an Electron Energy Loss (EEL) Spectrum. Thus, in an EEL Spectrum the ordinate axis corresponds to the number of electrons, or counts, and the abscise corresponds to the Energy Loss.
Notice that most electrons shall not suffer any inelastic scattering whatsoever. As a consequence, the greatest contribution to the spectrum is due to these electrons having lost zero energy, giving rise to the so-called zero loss peak (ZLP). As for those electrons having lost a certain amount of energy, they may lose it to ionization of specimen electrons, transitions from occupied core states to unoccupied core states or to conduction band states, to interband transitions or excitations of collective vibrations of conduction band electrons.
Incident electrons carry a given momentum, and it is worth keeping in mind that in an inelastic scattering event not only energy, but also momentum, may be transferred. In fact, this is the reason why it is not straightforward to compare EELS results with those obtained by means of optic spectroscopies.
EELS detectors can provide an energy resolution down to the order of the 0.1 eV. In addition, incident electrons can be tuned by TEM optics, making it possible to get spectroscopic information from an extremely constrained area, and to combine EEL Spectroscopy with TEM imaging.En el microscopi electrònic de transmissió (TEM), un electró incident sofreix tant xocs elàstics com inelàstics en travessar la mostra prima d’estat sòlid que s’està caracteritzant. En cas de xoc inelàstic, l’electró incident cedeix part de la seva energia als electrons de la mostra. La quantitat d’energia perduda es pot mesurar amb un filtre magnètic situat al final de la columna, i un gràfic que indiqui quants electrons han perdut quina quantitat d’energia ens donarà un espectre de pèrdua d’energia dels electrons, o espectre EELS. Així, en un espectre EELS l’ordenada correspon al número d’electrons, o comptes, i l’abscissa, a la pèrdua d’energia. Avui en dia l’EELS s’ha convertit en un instrument crucial a la ciència de materials, per causa de la progressiva reducció de l’escala característica implicada en el desenvolupament d’aquesta disciplina, i també gràcies a la millora instrumental que ha tingut lloc en els darrers anys tant en la microscòpia electrònica en general com en l’EELS en particular. En aquesta tesi, s’han explorat les capacitats de l’EELS com a eina de caracterització de mostres d’estat sòlid a la nanoescala, i s’han aplicat a diversos problemes de ciència de materials.
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Zhang, Jingmin. "Application of electron energy-loss spectroscopy to ferroelectric thin films." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=974145971.
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Wachsmuth, Philipp [Verfasser]. "Momentum-resolved electron energy-loss spectroscopy of graphene / Philipp Wachsmuth." Ulm : Universität Ulm. Fakultät für Naturwissenschaften, 2014. http://d-nb.info/1054045453/34.
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Bergenius, Gavler Sara. "Counting Calories : Studies of Energy Loss in a Segmented Calorimeter." Doctoral thesis, Stockholm, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3920.
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Walsh, Caroline Annabelle. "Modelling and interpretation of electron energy-loss spectra from interfaces." Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316804.
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Ahn, C. C. "Methods of deconvolution and quantification for electron energy loss spectroscopy." Thesis, University of Bristol, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375376.
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Kolbe, Isobel. "pQCD energy loss and thermal field theory in small systems." Doctoral thesis, Faculty of Science, 2019. http://hdl.handle.net/11427/30385.
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In recent years, experiments at the Large Hadron Collider and the Relativistic Heavy Ion Collider have discovered that many of the signatures that are traditionally ascribed to the presence of a quark-gluon plasma (QGP) in central heavy-ion collisions also manifest in certain classes of peripheral heavy-ion collisions as well as in smaller colliding systems. The glaring exception to this list of observations of QGP signatures in small systems is the partonic energy loss. However, current theoretical descriptions of partonic energy loss are ill-adapted to small systems. This thesis first presents a numerical analysis of an analytical small system extension of a standard energy loss formula, and finds that major inconsistencies in the description of small system energy loss persist, motivating a need for a first principles calculation of the properties of a small droplet of QGP. Thereafter, a first step toward such a calculation is presented by considering a single, massless, scalar field that has been geometrically confined by means of Dirichlet boundary conditions. This toy model reveals, via thermal field theoretic techniques, that quantum fields are very sensitive to the presence of a boundary, presenting significant deviations from the Stefan-Boltzmann limit and revealing a geometrically driven phase transition at the scale of the medium.
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Wang, Ya-Xin. "Electron energy loss analysis for diamond and diamondlike carbon materials." Case Western Reserve University School of Graduate Studies / OhioLINK, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=case1054837163.
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Seabourne, Che Royce. "Electron energy-loss spectroscopy : DFT modelling and application to experiment." Thesis, University of Leeds, 2010. http://etheses.whiterose.ac.uk/1447/.
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The all-electron density functional theory (DFT) code Wien2k has an established track record of modelling energy-loss near-edge structure (ELNES). The pseudopotential DFT code CASTEP can reproduce results found using Wien2k. A methodology was developed for DFT code parameter selection, based on converging parameters to the ELNES prediction. Various aluminium systems were studied; aluminium, aluminium nitride and aluminium oxide. Uniquely for aluminium metal, a ground state calculation provided strong agreement with experiment, as the core-hole is well screened. It was quantitatively demonstrated that the core-hole causes ionisation edge peaks to shift towards the Fermi level, and increases the intensity of those peaks - effects found to be larger for the cationic species. Group 4 and 5 transition metal carbides were modelled using CASTEP. Systems with vacancies were considered; TiC0.79, TiC0.58N0.30, TiC0.45N0.43, TiC0.19N0.65 and TiN0.82. By comparison with experimental data, structures for these systems were proposed. CASTEP was used to model oxygen K edges in various systems. For bulk MgO, acceptable experimental agreement was found using a ground state calculation. This was rationalised by observing that the introduction of a corehole had relatively little effect on the p orbital DOS prediction for oxygen. For the interface of Fe (001) / MgO (001), it was demonstrated by careful comparison of theory and experiment that some degree of oxidation was present. Nanoscale analysis of multilayered CrAlYN/CrN coatings was performed. Experimentally observed ELNES was reproduced using ground state Wien2k calculations. Combined experimental and theoretical analysis indicated that the nominal CrN layers were close to stoichiometric CrN, the Cr/N ratio being 1.05 ± 0.1. For the CrAlYN layers, the theoretical system showing the best agreement was Cr0.5Al0.5N. This thesis has established methodologies for utilising DFT codes, illustrating how links between experimental and theoretical ELNES can be used in the nanoscale characterisation of technologically important materials.
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Sjödin, Emma. "The Price of Synchrony:Evaluating Transient Power Losses inRenewable Energy IntegratedPower Networks." Thesis, KTH, Reglerteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-133579.
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This thesis investigates the resistive losses incurred in returning a power network to a synchronous state following a transient stability event, or in maintaining this state in the presence of persistent stochastic disturbances. We quantify these transient power losses, the so-called “Price of Synchrony”, using the squared H2 norm of a linear system of generator and load dynamics subject to distributed disturbances. We first consider a large network of synchronous generators and use the classical machine model to form a system with coupled second order swing equations. We then extend this model to explicitly include dynamics of loads and asynchronous generators, which represent solar and wind power plants. These elements are modeled as frequency-dependent power injections (extractions), and the resulting system is one of coupled firstand second order dynamics. In both cases, the disturbance inputs represent power fluctuations due to transient stability events or the inherent variability of loads and intermittent energy sources. The network structure is captured through a weighted graph Laplacian of the network admittance. In order to simplify the analysis for both models, we use the concept of grounded graph Laplacians to obtain an asymptotically stable reduced system. We then evaluate the transient losses in the reduced system and show that this system’s H2 norm is in fact equivalent to the H2 norm of the original system. Furthermore we show that although the transient behaviours of the first order, second order or mixed dynamical systems are in general fundamentally different, for same-sized networks they may all have the same H2 norm if the damping coefficients are uniform. The H2 norms for both system models are shown to be a function of transmission line and generator properties and to scale with the network size. These transient losses do not, however, depend on the network connectivity. This is in contrast to related power system stability notions that predict better synchronous stability properties for highly connected networks. The equivalence of the norms for different order systems indicate that renewable energy sources will not increase transient power losses if their controllers can be adjusted to match the dampings of existing synchronous generators. However, since the losses scale linearly with the number of generators, our results also demonstrate that increased amounts of distributed generation in low-voltage grids will lead to larger transient losses, and that this effect cannot be alleviated by increasing the network connectivity.
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CALILI, RODRIGO FLORA. "SYSTEM DEVELOPMENT TO DETECT COMMERCIAL LOSSES IN ELECTRICAL ENERGY DISTRIBUTION NETWORK." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2005. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=7629@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOROs modelos matemáticos comumente usados na identificação de irregularidades na medição se baseiam na análise da redução percentual do consumo do mês (normalmente de 20% a 30%) em relação aos meses anteriores. Este método tem gerado resultados imprecisos uma vez que considera o valor do consumo como um valor rígido e, portanto, não incorpora o efeito da sazonalidade na tipologia das cargas das unidades consumidoras. Este trabalho tem o intuito de melhorar a identificação de clientes fraudulentos utilizando métodos de inteligência artificial, tais como Redes Neurais e Lógica Fuzzy, implementados a um banco de dados de cadastro da Distribuidora de Energia ELEKTRO e a uma Pesquisa de Posses e Hábitos de Consumo (PPH) feita nesta mesma empresa. Nesta dissertação, o objetivo foi classificar um grupo de consumidores como normal (adimplente), inadimplente e fraudulento. Para tanto, foi feita inicialmente uma clusterização utilizando uma Rede Neural, mais especificamente uma Rede de Kohonen, para o banco de dados de cadastro disponibilizado pela distribuidora. Tomando os grupos desta classificação prévia feita pela Rede identificaram-se quais e quantos destes tiveram PPH´s realizadas. Para se ter a classificação de um grupo quanto a incidência de consumidores normais, inadimplentes e fraudulentos utilizou-se um processo de Análise Fuzzy, o qual identifica os clusters com os consumidores de cada um dos segmentos. É feita uma análise de desempenho do modelo proposto com dados reais fornecidos pela empresa, na qual os resultados apontaram para uma robustez do método.
Mathematical models commonly used to identify irregularities in measurement are based on percentile reduction analysis of the monthly consumption (normally from 20% to 30%) in relation to the previous months. This method tends to generate imprecise results, since it considers the value of the consumption as a rigid value and, therefore, it does not incorporate the seasonal effect in the loads topology of the consumer units. This work has intention to improve the identification of fraudulent customers using artificial intelligence methods, such as Neural Networks and Fuzzy Logic, implemented to a database of consumers of ELEKTRO a distributing utility of São Paulo State, Brazil. It also uses information on appliances ownership obtained via market research in ELEKTRO area, named PPH (Portuguese for this particular type of market research). In this dissertation, the main objective was to classify a group of consumers as solvent, insolvent and fraudulent. In order to achieve this task, a clustering was initially made using a Neural Network framework, more specifically a Kohonen Network, for the database available. It was then checked which of the groups had a minimum number of clients interviewed in the PPH. In order to have the classification of the clients in the three categories it was used Fuzzy Analysis. Selected data is also presented, considering the available database of the Company as well as the research environment, which had been taken from the PPH. Finally, it was checked the performance of the method against real data obtained from the utility and the results were very satisfactory.
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ASEVEDO, FRANCIS ROCHA DE. "GENERALIZED LINEAR APPROACH TO ESTIMATE NON-TECHNICAL LOSSES OF ELECTRICAL ENERGY." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2011. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=18163@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROA necessidade de simular um ambiente de mercado competitivo para incentivar ganhos de eficiência fez a Agência Nacional de Energia Elétrica (ANEEL) estipular metas para indicadores gerenciáveis, dentre eles o nível de perdas não técnicas (PNT’s) das distribuidoras de energia elétrica. Os prejuízos causados pelas perdas não técnicas de energia chegam à ordem de oito bilhões de reais anuais e impactam diretamente nos valores tarifários em exercício. É nesse contexto que a ANEEL, inspirada nas práticas de regulação por incentivo, estabeleceu um modelo econométrico que relaciona o nível aceitável de perdas não técnicas com a complexidade social das áreas de concessão das distribuidoras brasileiras. Entretanto, entidades do setor enxergam no modelo espaços para melhoria nos resultados e na robustez teórica do modelo, com isso, surge a idéia de propor uma abordagem de estimação diferenciada. É importante ressaltar que além da previsão, tem-se por objetivo testar novas variáveis potencialmente relevantes nesta análise, baseadas na recente literatura acerca do tema. O presente estudo demonstra que a variável de interesse, perdas não técnicas, não segue a distribuição normal, sendo assim, buscou-se a verdadeira distribuição dos dados e a modelagem se deu seguindo os arcabouços da abordagem linear generalizada. Os resultados corroboraram a aderência de uma distribuição que pertence a família exponencial (condição para a aplicação da abordagem linear generalizada). Além disso, o modelo proposto obteve boas estimativas, trazendo inclusive novas variáveis importantes para explicar as perdas não técnicas não utilizadas antes em outros estudos sobre estas perdas. O modelo proposto pode ser visto como uma alternativa viável ao modelo praticado pela ANEEL, sendo assim, sua discussão fundamental para o próximo ciclo de revisão tarifária.
The need of simulating a competitive market environment in order to encourage efficiency gains made the National Electrical Energy Agency (ANEEL) fixes targets for manageable indicators, including the level of non-technical losses (NTL s) of electricity distributors. The financial damage caused by losses not techniques reach the order of eight billion reais per year and directly impacts on the electricity tariffs. In this context, ANEEL inspired by the practice of regulation by incentives, established an econometric model that relates the acceptable level non-technical losses to the social complexity in concession areas of each Brazilian distributor. However, entities in the sector find gaps in the model and improvement in the results and robustness of the model should be done, this brings idea of proposing a different approach to the estimation. It is important to emphasize that in addition to forecasting, there is the willing of testing new variables potentially relevant in this analysis, based on recent literature on the subject. This study proves that the variable of interest, nontechnical losses, does not follow the Gaussian distribution, thus, we sought the true distribution of data and modeling took place in the frameworks of general linear approach. The results confirm adherence to a distribution that belongs to the exponential family (condition for applying the generalized linear approach model), in addition, the proposed model obtained good estimates, including the use of new important variables to explain the non-technical losses not used in other studies. The proposed model can be seen as possible alternative to the model used by ANEEL, so, its discussion is really important to the next review cycle of electricity rates.