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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Affärsmodellsinnovation för använda elbilsbatterier : En studie kring hinder, utmaningar och möjliga utfall av implementering av affärsmodellsinnovation för återanvändning av elbilsbatterier

Alizade, Ali, Khoshnaw, Diar January 2023 (has links)
Detta examensarbete är tillägnad att undersöka hur affärsmodellsinnovation kan skapa förutsättningar för att underlätta återanvändandet av elbilsbatterier samt analysering av möjliga värdeskapande utfall. Arbetet fokuserar på att samla data från större aktörer som hanterar begagnade elbilsbatterier. Kartläggning av deras affärsmodeller genom kvalitativa intervjuer ger läsaren och författarna en större inblick kring hur cirkulära affärsmodeller fungerar och vart de behöver innovation.  Elbilar har det senaste decenniet en större andel av nybilsförsäljningen och med direktiv från både EU och den svenska staten, kommer det ebdast vara möjligt att köpa eldrivna samt vissa gasdrivna fordon från 2035. Detta medför en större batteriproduktion vilket även leder till en större grad av exploatering av nuvarande litium- och molybden reserver. Dessa reserver kommer att räcka i ca 70 år om inte nya tillgångar upptäcks och större fokus på att kunna återanvända blir aktuellt.  Denna omfattande gröna omställning av bilindustrin sätter även press på batteri producenter till en mer hållbar tillverkning som tar hänsyn till behovet av att kunna återvinna/återanvända. Denna eftertraktade designförslag är däremot något nytt hos många producenter och resterande verkar inte kunna nå en optimal grad av återvinningsberhet. Kvar blir alternativet att kunna återanvända batterierna från den befintliga elbilsmarknaden. Denna studie inspireras av cirkulär ekonomi och cirkulära affärsmodeller som kan effektivt handskas med problemen dem begagnade elbilsbatterierna för med sig. Studiens forskningsfrågor grundar sig först och främst hur befintliga affärsmodeller ser ut, vad för innovation det krävs samt hur denna innovation kan skapa förutsättningar för återanvändning.  Kartlägning av affärsmodeller från större återanvändning/återvinnings aktörer såsom Northvolts dotterföretag Revolt samt Stena Recycling, BatteryLoop, visar på ett behov av en mer intergrerad spårning och distrubering av själva elbilsbatterierna. Studien visar att affärsmodellsinnovation behövs inom uppsamling av begagande elbilsbatterier där en digital plattform möjliggör interaktion mellan köpare och säljare. Dessutom kontrolleras varje begagnat batteri innan den når marknaden vilket skapar fler förutsättningar för cirkularitet och främjar återvinning. / This thesis is dedicated to investigating how business model innovation can create the conditions to facilitate the reuse of electric car batteries as well as analyzing possible value-creating outcomes. The work focuses on gathering data from major players who handle used electric car batteries. Mapping their business models through qualitative interviews gives the reader and the authors a greater insight into how circular business models work.  In the last decade, electric cars have taken larger share of the new car sale och with directives from both the EU and the Swedish state, it will only be possible to buy electric-powered abd sin gas-powered vehicles from 2035. This entails a greater battery production, which also leads to a greater degree of exploitation of current lithium and molybdenum reserves. These reserves will last for about 70 years unless new assets are discovered and a greater focus on being able to reuse and recycle becomes relevant.  This comprehensive green transformation of the car industry also puts pressure on battery producers to a more sustainable production that considers the need to be able to be recycled/reused.However, this sought-after design proposal is something new for many producers and the rest do not seem to be able to reach an optimal degree of recyclability. What remains is the option of being able to reuse the batteriers from the existing electric car market. This study is inspired by circular economy and circular business models that can effectively deal with the problems that used electric car batteries bring with them. The study's resarch questions are first and foremost based on what existing business models look like, what kind of innovation is required and how this innovation can create conditions for reuse. Mapping of business models from major reuse/recycling actors such as North Volts's subsidiary Revolt and Stena Recycling, Battery Loop, shows a need for more intergrated tracking and distribution of the electric car batteriers themselves.  This study shows that business model innovation is needed in the collection of used electric car batteries where a digital plattform enables interaction between buyers and sellers. In addition, every used battery is checked before it reaches the market, which creates more conditions for circularity and promotes recycling.
32

Li-ion titanate technology for SLI battery applications in commercial vehicles / Li-jon titanat teknologi för SLI-batteritillämpning i kommersiella fordon

Vasilevich, Liliya January 2021 (has links)
Litiumjon-batterier har blivit väldigt populära för tillämpning i fordon. Den här teknologin har fler olika kemier att erbjuda som kontinuerligt förbättras. Litium-titanat-oxid-batterier använder (LTO) LTO som anod och erbjuder långt cyklingsliv samt minskar risk för SEI-bildning och litiumplätering.  Det här examensarbetet siktade på att undersöka om LTO-batterier kan användas som startbatterier i kommersiella fordon. Metodologin inkluderade två motorstart försök med en kommersiell 12s1p LTO-modul, laddnings/urladdningtester med en kommersiell LTO-cell med nominell spänning 2.3V samt överurladdningstester med byggda pouchceller. Materialet för pouchceller extraherades från en kommersiell LTO-cell och sedan studerades med SEM-EDX före och efter överurladdningstesterna. Resultatet visade att LTO-batterier kan användas som startbatterier i en diesel V8 motor även vid 39%SoC. Dessutom visade simuleringar att LTO-batterier kan användas inom Kinetic Energy Recovery System (KERS) tillämpning och behålla 60% SoC efter 500 laddning/urladdnings cykler. Resultaten från både KERS och motorstarterna visade att LTO är en lovande kandidat för ersättning av blybatterier. Laddnings/urladdnings tester visade att en kommersiell 12s1p LTO modul kan maximalt uppnå 73%SoC när den laddas med fordon-liknande strömmar. Däremot var SoC oberoende av laddningsström. Överurladdningstester med pouchceller visade att det är relativt ofarligt att urladda LTO 0.4V under spänningsgränsen utan stora ökningar i impedans eller stor kapacitetsförlust. Största förluster kopplades till åldring av NMC-baserade positiva elektroden. / Lithium ion batteries have become quite popular in vehicle applications in the past few decades. This technology offers multiple chemistries to choose from, that are continuously studied and improved. Lithium-titanate-oxide (LTO) batteries use LTO material as an anode, providing long cycling life, as well as essentially eliminating risk for SEI formation and lithium plating.  This Master thesis project aimed to investigate how well LTO-based lithium-ion batteries can perform in Start Ignition Lighting (SLI) application in commercial vehicles. The methodology included two engine crank tests with a commercial 12s1p LTO module, charge/discharge tests on a commercial LTO cell with nominal voltage 2.3V, as well as overdischarge cycling tests on assembled pouch cells. The materials for the pouch cells were extracted from a commercial LTO cell and later analysed with SEM-EDX before and after overdischarge tests. The results demonstrated that LTO-based Li-ion batteries can be successfully start a diesel V8 engine even at 39% SoC. Furthermore, when simulating an urban vehicle with an implemented Kinetic Energy Recovery System (KERS) application, a commercial cell LTO cell achieved and retained around 60\%SoC throughout 500 charge/discharge cycles. Combined results from KERS and engine start tests imply that LTO is a strong candidate for replacing lead-acid in these applications. Charge/discharge tests showed that commercial 12s1p LTO cell can maximum reach around 73%SoC when charged in a vehicle-like way. However, this maximum SoC limit was more or less independent of applied charging current. Furthermore, electrochemical overdischarge tests on the pouch cells demonstrated that it is relatively safe to overdischarge the cell 0.4V below the specified safety limit without significant rise in impedance or capacity fade. Major performance losses were attributed to the aging of the NMC-based positive electrode.
33

Análise da função renal em idosos com comprometimento cognitivo leve usuários de lítio em baixa dosagem: um estudo randomizado, duplo cego, placebo-controlado / Analysis of the renal function in elderly with mild cognitive impairment using lithium in low dose: a randomized, double-blind, placebo- controlled study

Aprahamian, Ivan 25 June 2013 (has links)
Introdução: segundo a literatura, sais de lítio podem produzir redução da função renal. A magnitude dessa informação é debatível, uma vez que não há estudo clínico randomizado e controlado entre usuários de lítio, em sua maioria pacientes com depressão ou transtorno bipolar. A possibilidade do uso do lítio para o tratamento da demência de Alzheimer prodrômica reforça a necessidade de maior investigação de efeitos adversos atribuídos ao lítio, especialmente com relação à função renal. Objetivos: avaliar a segurança da utilização do lítio em baixa dosagem com relação à função renal de pacientes idosos. Como objetivos secundários serão avaliadas: a segurança clínica através de exame e questionário específico, as funções tireoidiana, imunológica e o metabolismo glicêmico. Métodos: estudo randomizado e placebo controlado de 2 anos, seguido de fase aberta por mais 2 anos. Foram avaliados 59 idosos com comprometimento cognitivo leve com seguimento mínimo de dois anos (fase controlada). A função renal foi estimada através das fórmulas aMDRD e CKD- EPI, a partir de exames laboratoriais e dados clínicos coletados durante o estudo. As funções tireoidiana, imunológica e glicêmica foram avaliadas respectivamente através de TSH, T4 livre, leucócitos total, neutrófilos, linfócitos, glicemia e insulinemia de jejum, e HOMA-IR. A segurança clínica foi avaliada através de entrevista sistemática realizada a cada 3 meses, utilizando exame físico e a escala UKU para efeitos adversos. Resultados: não houve piora da função renal com o uso do lítio (litemia entre 0,25-0,5 mmol/l) tanto pela aMDRD (p=0,453) como pela CKD-EPI (p=0,181). Houve aumento significativo de neutrófilos (p=0,038) e do TSH (p=0,034). O grupo lítio apresentou incidência significativamente maior de diabetes mellitus (p=0,037) e arritmias (p=0,028), maior ganho de peso (p=0,015), mais sintomas na escala UKU (p=0,045), e maior interferência dos efeitos adversos do lítio em atividades diárias (p<0,001). Houve correlação entre a opinião de médico e do paciente nas interferências das atividades diárias atribuídas aos sintomas adversos (p<0,001). Conclusões: o uso de lítio em baixa dose não alterou a função renal, produziu alterações no sistema imunológico e tireoidiano sem impacto clínico, e foi seguro clinicamente. As razões do aumento de incidência de diabetes e arritmias merecem investigação posterior / Introduction: according to the literature, lithium salts may produce a reduction in kidney function. The magnitude of this information is debatable because there is no randomized and controlled clinical trial among lithium users, being mostly patients with depression or bipolar disorder. The possibility of using lithium for the treatment of prodromal Alzheimer\'s disease dementia increases the need for further investigation of adverse effects attributed to lithium, especially regarding to renal function. Objectives: To evaluate the safety of using low-dose lithium with respect to renal function in elderly patients. Secondary objectives were the evaluation of the clinical safety through specific questionnaire and clinical assessment, and to assess thyroid, immunological and glycemic function. Methods: a randomized and placebo controlled study for 2 years, followed by an open label follow-up of 2 years. We evaluated 59 elderly patients with mild cognitive impairment with accomplishment of at least two years of the controlled phase. Renal function was estimated by the aMDRD and CKD-EPI equation, and by laboratory and clinical data collected during the trial. The thyroid, immunological and glycemic functions were respectively evaluated by TSH, free T4, leukocyte count, neutrophil count, lymphocyte count, fasting plasma glucose and insulin, and the HOMA-IR. The clinical safety was evaluated through systematic examination performed every 3 months, with physical examination, clinical interview and UKU scale for adverse effects. Results: There was no decline of renal function with the use of lithium (litemia between 0.25-0.5 mmol/l) both in the aMDRD (p=0.453) and CKD-EPI (p=0.181) equations. A significant increase of neutrophils (p=0.038) and TSH (p=0.034) were observed. The lithium group showed significantly higher incidence of diabetes mellitus (p=0.037), arrhythmias (p=0.028), weight gain (p=0.015), more symptoms of UKU scale (p=0.045), and greater interference from the adverse effects of lithium during daily activities (p<0.001). There was an observed correlation between the opinion of the attending physician and the patient in respect to the interference in daily activities secondary to the adverse symptoms (p<0.001). Conclusions: The use of lithium in low doses did not result in renal function impairment, produced subtle changes in the immunological system and thyroid function, and was clinically safe for adverse effects. The reasons for the increased incidence of arrhythmias and diabetes mellitus deserve further investigation
34

Gestion de l'énergie dans un système multi-sources photovoltaïque et éolien avec stockage hybride batteries/supercondensateurs

Croci, Lila 18 December 2013 (has links) (PDF)
Ce mémoire présente le travail de recherche effectué pour la conception d'une stratégie de commande originale, destinée aux systèmes de puissance hybrides en sites isolés. Le système considéré, voué à l'alimentation électrique d'une habitation, comprend deux sources, un groupe de panneaux photovoltaïques et une petite éolienne, et deux types de stockage, un banc de batteries lithium-ion et un de supercondensateurs. Face au problème de gestion de l'énergie dans un système hybride, et aux enjeux de maximisation de sa puissance produite, nous proposons de développer une stratégie de commande basée sur les flux d'énergie. pour cela, nous présentons dans un premier temps les modélisations d'Euler-Lagrange et hamiltonienne du système. Ces modèles permettent d'utiliser la propriété de passivité de celui-ci, et ainsi de synthétiser des commandes par injection d'amortissement pour chaque source, afin de maximiser sa production, et pour les supercondensateurs, dans le but d'assurer une répartition cohérente des flux d'énergie entre eux et les batteries. Les commandes sont finalement mises en œuvre dans un simulateur, puis dans un banc d'essai expérimental, afin d'une part de comparer leurs performances à celles de solutions préexistantes, et d'autre part de valider le bon fonctionnement du système hybride complet les utilisant.
35

Gestion de l'énergie dans un système multi-sources photovoltaïque et éolien avec stockage hybride batteries/supercondensateurs / Energy management in a photovoltaic/wind hybrid power system with batteries/supercapacitors storage

Croci, Lila 18 December 2013 (has links)
Ce mémoire présente le travail de recherche effectué pour la conception d'une stratégie de commande originale, destinée aux systèmes de puissance hybrides en sites isolés. Le système considéré, voué à l'alimentation électrique d'une habitation, comprend deux sources, un groupe de panneaux photovoltaïques et une petite éolienne, et deux types de stockage, un banc de batteries lithium-ion et un de supercondensateurs. Face au problème de gestion de l'énergie dans un système hybride, et aux enjeux de maximisation de sa puissance produite, nous proposons de développer une stratégie de commande basée sur les flux d'énergie. pour cela, nous présentons dans un premier temps les modélisations d'Euler-Lagrange et hamiltonienne du système. Ces modèles permettent d'utiliser la propriété de passivité de celui-ci, et ainsi de synthétiser des commandes par injection d'amortissement pour chaque source, afin de maximiser sa production, et pour les supercondensateurs, dans le but d'assurer une répartition cohérente des flux d'énergie entre eux et les batteries. Les commandes sont finalement mises en œuvre dans un simulateur, puis dans un banc d'essai expérimental, afin d'une part de comparer leurs performances à celles de solutions préexistantes, et d'autre part de valider le bon fonctionnement du système hybride complet les utilisant. / This thesis presents the research about design of a new control strategy for stand-alone hybrid power systems. The considered system is composed of two sources, a group of photovoltaic panels and a low-power wind generator, and of two kinds of storage, a bank of lithium-ion batteries and one of supercapacitors. Faced with the problem of energy management in a hybrid power system, and with necessity of maximizing the produced power, we intend to develop an energy-based control strategy.For this purpose, we present the system's Euler-Lagrange modeling and Hamiltonian modeling. These models allow the use of the passivity property, and then the design of Passivity-Based Controllers for each source, in order to maximize its production, and for the supercapacitors, to ensure a fitted power sharing between batteries and them. The controllers are finally implemented in a simulator, and then in a experimental test bench, in order to compare their performances to pre-existent solutions, and tovalidate the control law for the global hybrid system.
36

Análise da função renal em idosos com comprometimento cognitivo leve usuários de lítio em baixa dosagem: um estudo randomizado, duplo cego, placebo-controlado / Analysis of the renal function in elderly with mild cognitive impairment using lithium in low dose: a randomized, double-blind, placebo- controlled study

Ivan Aprahamian 25 June 2013 (has links)
Introdução: segundo a literatura, sais de lítio podem produzir redução da função renal. A magnitude dessa informação é debatível, uma vez que não há estudo clínico randomizado e controlado entre usuários de lítio, em sua maioria pacientes com depressão ou transtorno bipolar. A possibilidade do uso do lítio para o tratamento da demência de Alzheimer prodrômica reforça a necessidade de maior investigação de efeitos adversos atribuídos ao lítio, especialmente com relação à função renal. Objetivos: avaliar a segurança da utilização do lítio em baixa dosagem com relação à função renal de pacientes idosos. Como objetivos secundários serão avaliadas: a segurança clínica através de exame e questionário específico, as funções tireoidiana, imunológica e o metabolismo glicêmico. Métodos: estudo randomizado e placebo controlado de 2 anos, seguido de fase aberta por mais 2 anos. Foram avaliados 59 idosos com comprometimento cognitivo leve com seguimento mínimo de dois anos (fase controlada). A função renal foi estimada através das fórmulas aMDRD e CKD- EPI, a partir de exames laboratoriais e dados clínicos coletados durante o estudo. As funções tireoidiana, imunológica e glicêmica foram avaliadas respectivamente através de TSH, T4 livre, leucócitos total, neutrófilos, linfócitos, glicemia e insulinemia de jejum, e HOMA-IR. A segurança clínica foi avaliada através de entrevista sistemática realizada a cada 3 meses, utilizando exame físico e a escala UKU para efeitos adversos. Resultados: não houve piora da função renal com o uso do lítio (litemia entre 0,25-0,5 mmol/l) tanto pela aMDRD (p=0,453) como pela CKD-EPI (p=0,181). Houve aumento significativo de neutrófilos (p=0,038) e do TSH (p=0,034). O grupo lítio apresentou incidência significativamente maior de diabetes mellitus (p=0,037) e arritmias (p=0,028), maior ganho de peso (p=0,015), mais sintomas na escala UKU (p=0,045), e maior interferência dos efeitos adversos do lítio em atividades diárias (p<0,001). Houve correlação entre a opinião de médico e do paciente nas interferências das atividades diárias atribuídas aos sintomas adversos (p<0,001). Conclusões: o uso de lítio em baixa dose não alterou a função renal, produziu alterações no sistema imunológico e tireoidiano sem impacto clínico, e foi seguro clinicamente. As razões do aumento de incidência de diabetes e arritmias merecem investigação posterior / Introduction: according to the literature, lithium salts may produce a reduction in kidney function. The magnitude of this information is debatable because there is no randomized and controlled clinical trial among lithium users, being mostly patients with depression or bipolar disorder. The possibility of using lithium for the treatment of prodromal Alzheimer\'s disease dementia increases the need for further investigation of adverse effects attributed to lithium, especially regarding to renal function. Objectives: To evaluate the safety of using low-dose lithium with respect to renal function in elderly patients. Secondary objectives were the evaluation of the clinical safety through specific questionnaire and clinical assessment, and to assess thyroid, immunological and glycemic function. Methods: a randomized and placebo controlled study for 2 years, followed by an open label follow-up of 2 years. We evaluated 59 elderly patients with mild cognitive impairment with accomplishment of at least two years of the controlled phase. Renal function was estimated by the aMDRD and CKD-EPI equation, and by laboratory and clinical data collected during the trial. The thyroid, immunological and glycemic functions were respectively evaluated by TSH, free T4, leukocyte count, neutrophil count, lymphocyte count, fasting plasma glucose and insulin, and the HOMA-IR. The clinical safety was evaluated through systematic examination performed every 3 months, with physical examination, clinical interview and UKU scale for adverse effects. Results: There was no decline of renal function with the use of lithium (litemia between 0.25-0.5 mmol/l) both in the aMDRD (p=0.453) and CKD-EPI (p=0.181) equations. A significant increase of neutrophils (p=0.038) and TSH (p=0.034) were observed. The lithium group showed significantly higher incidence of diabetes mellitus (p=0.037), arrhythmias (p=0.028), weight gain (p=0.015), more symptoms of UKU scale (p=0.045), and greater interference from the adverse effects of lithium during daily activities (p<0.001). There was an observed correlation between the opinion of the attending physician and the patient in respect to the interference in daily activities secondary to the adverse symptoms (p<0.001). Conclusions: The use of lithium in low doses did not result in renal function impairment, produced subtle changes in the immunological system and thyroid function, and was clinically safe for adverse effects. The reasons for the increased incidence of arrhythmias and diabetes mellitus deserve further investigation
37

Estudo de compostos LiMePO4 (Me=Mg, Co, Ni) através de Ressonância Magnética Nuclear / Studies of LiMePO4 (Me = Mg, Co, Ni) compounds through Nuclear Magnetic Resonance

Silva, Marcos Antonio da 06 October 2000 (has links)
Nesta dissertação é apresentado um estudo dos compostos Li1-3xMgFexPO4 através de Ressonância Magnética Nuclear (7Li e 31P), no intervalo de temperatura de 150 a 410 K. Estudos desses compostos através de técnicas de difração de elétrons e efeito Mossbauer confirmam que os íons Fe entram na rede cristalina na forma Fe3+, substituindo os íons Li+. O comportamento dos espectros de RMN, dos tempos de relaxação spin-rede e da susceptibilidade magnética dos núcleos 7Li e 31P em função da temperatura, em conjunto com medidas de condutividade iônica, indicam que, mesmo com a adição de impurezas Fe3+ na rede, os íons Li+ pouca mobilidade dentro do intervalo de temperatura utilizado. / This work reports a 7Li and 31P nuclear magnetic resonance study in the Li1-3xMgFexPO4 phases between 150 and 410 K. This study, complementary to those made using Mössbauer and magnetic neutron diffraction experiments, confirms that the Fe3+ ions enter as in the lattice, and that they enter substituting Li ions. The behavior of the 7Li e 31P nuclear magnetic resonance spectra, together with ionic conductivity measurements, show that no Li mobility occurs in temperature range studied even with the addition of the Fe impurity.
38

Estudo de compostos LiMePO4 (Me=Mg, Co, Ni) através de Ressonância Magnética Nuclear / Studies of LiMePO4 (Me = Mg, Co, Ni) compounds through Nuclear Magnetic Resonance

Marcos Antonio da Silva 06 October 2000 (has links)
Nesta dissertação é apresentado um estudo dos compostos Li1-3xMgFexPO4 através de Ressonância Magnética Nuclear (7Li e 31P), no intervalo de temperatura de 150 a 410 K. Estudos desses compostos através de técnicas de difração de elétrons e efeito Mossbauer confirmam que os íons Fe entram na rede cristalina na forma Fe3+, substituindo os íons Li+. O comportamento dos espectros de RMN, dos tempos de relaxação spin-rede e da susceptibilidade magnética dos núcleos 7Li e 31P em função da temperatura, em conjunto com medidas de condutividade iônica, indicam que, mesmo com a adição de impurezas Fe3+ na rede, os íons Li+ pouca mobilidade dentro do intervalo de temperatura utilizado. / This work reports a 7Li and 31P nuclear magnetic resonance study in the Li1-3xMgFexPO4 phases between 150 and 410 K. This study, complementary to those made using Mössbauer and magnetic neutron diffraction experiments, confirms that the Fe3+ ions enter as in the lattice, and that they enter substituting Li ions. The behavior of the 7Li e 31P nuclear magnetic resonance spectra, together with ionic conductivity measurements, show that no Li mobility occurs in temperature range studied even with the addition of the Fe impurity.

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