Letteratura scientifica selezionata sul tema "Combustion LIBS"
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Articoli di riviste sul tema "Combustion LIBS"
1
Sheta, Sahar, Muhammad Sher Afgan, Zongyu Hou, Shun-Chun Yao, Lei Zhang, Zheng Li e Zhe Wang. "Coal analysis by laser-induced breakdown spectroscopy: a tutorial review". Journal of Analytical Atomic Spectrometry 34, n. 6 (2019): 1047–82. http://dx.doi.org/10.1039/c9ja00016j.
Testo completoAbstract (sommario):
This review article forms a guideline for LIBS contribution in coal analysis, encompassing fundamental aspects, operation modes, data processing, and analytical results. LIBS applications related to coal utilization are also highlighted (fly ash analysis and combustion monitoring).
2
Zhang, Hansheng, Jagdish P. Singh, Fang-Yu Yueh e Robert L. Cook. "Laser-Induced Breakdown Spectra in a Coal-Fired MHD Facility". Applied Spectroscopy 49, n. 11 (novembre 1995): 1617–23. http://dx.doi.org/10.1366/0003702953965759.
Testo completoAbstract (sommario):
A study of laser-induced breakdown spectroscopy (LIBS) has been performed in a particle-loaded methane/air flame and in the Diagnostic Instrumentation and Analysis Laboratory/Mississippi State University (DIAL/MSU) test stand to evaluate its application for practical environments. The LIBS spectra collected from different observational directions and spectral regions are compared. The forward LIBS technique has been chosen to characterize the upstream region of a large magnetohydrodynamics (MHD) coal-fired flow facility (CFFF). The relative concentrations of several species are inferred by fitting the observed CFFF LIBS spectra with computer-simulated spectra. This paper reports the first LIBS experiments in a harsh, turbulent, and highly luminous coal-fired MHD combustion environment.
3
Liu, Changcheng, Que Huang, Kaihui Zheng, Jiawen Qin, Dechuang Zhou e Jian Wang. "Impact of Lithium Salts on the Combustion Characteristics of Electrolyte under Diverse Pressures". Energies 13, n. 20 (15 ottobre 2020): 5373. http://dx.doi.org/10.3390/en13205373.
Testo completoAbstract (sommario):
The electrolyte is one of the components that releases the most heat during the thermal runaway (TR) and combustion process of lithium-ion batteries (LIBs). Therefore, the thermal hazard of the electrolyte has a significant impact on the safety of LIBs. In this paper, the combustion characteristics of the electrolyte such as parameters of heat release rate (HRR), mass loss rate (MLR) and total heat release (THR) have been investigated and analyzed. In order to meet the current demand of plateau sections with low-pressure and low-oxygen areas on LIBs, an electrolyte with the most commonly used lithium salts, LiPF6, was chosen as the experimental sample. Due to the superior low-temperature performance, an electrolyte containing LiBF4 was also selected to be compared with the LiPF6 sample. Combustion experiments were conducted for electrolyte pool fire under various altitudes. According to the experimental results, both the average and peak values of MLR in the stable combustion stage of the electrolyte pool fire had positive exponential relations with the atmospheric pressure. At the relatively higher altitude, there was less THR, and the average and peak values of HRR decreased significantly, while the combustion duration increased remarkably when compared with that at the lower altitude. The average HRR of the electrolyte with LiBF4 was obviously lower than that of solution containing LiPF6 under low atmospheric pressure, which was slightly higher for LiBF4 electrolyte at standard atmospheric pressure. Because of the low molecular weight (MW) of LiBF4, the THR of the corresponding electrolyte was larger, so the addition of LiBF4 could not effectively improve the safety of the electrolyte. Moreover, the decrease of pressure tended to increase the production of harmful hydrogen fluoride (HF) gas.
4
Lee, Won-Ju, Dae-Young Kim, Jae-Hyuk Choi, Ji-Woong Lee, Jun-Soo Kim, Kwangho Son, Min-Jae Ha e Jun Kang. "Utilization of Petroleum Coke Soot as Energy Storage Material". Energies 12, n. 16 (20 agosto 2019): 3195. http://dx.doi.org/10.3390/en12163195.
Testo completoAbstract (sommario):
Anode active materials for lithium ion batteries (LIBs) were produced by using waste soot generated after combustion in a plant using petroleum coke as fuel. The soot collected from the boilers in the plant was graphitized through annealing, and this annealed soot was applied to anode active materials. After annealing at 2700 °C, the soot was converted into highly crystalline graphite with ring shapes approximately 100 nm in diameter. The lithium ion coin cells produced using graphitized soot showed high discharge capacity and excellent life cycle with a reversible capacity of 250 mAh/g even after 300 cycles at a rate of 1 C. This study describes a new possibility of using environmentally harmful combustion wastes of petroleum coke as a low-price anode material for LIBs by converting them into a graphite multilayer structure with a unique ring shape through annealing.
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Pražanová, A., M. Havlík Míka e V. Knap. "Lithium-ion battery module-to-cell: disassembly and material analysis". Journal of Physics: Conference Series 2382, n. 1 (1 novembre 2022): 012002. http://dx.doi.org/10.1088/1742-6596/2382/1/012002.
Testo completoAbstract (sommario):
Lithium-ion batteries (LIBs) are one of the most popular energy storage systems. Due to their excellent performance, they are widely used in portable consumer electronics and electric vehicles (EVs). The ever-increasing requirements for global carbon dioxide CO2 emission reduction inhibit the production of new combustion vehicles. Thus, the demand for EVs increases, as well as the number of spent LIBs. Due to increases in raw materials saving and reduction in energy and environmental impacts, recycling is one of the most promising solutions for end-of-life (EOL) treatment for spent LIBs. This work describes the first step in recycling the LIBs nickel-manganese-cobalt (NMC) based module from a full battery electric vehicle (BEV) holding its high recycling efficiency and considering the process costs and environmental impact. This paper is devoted to module-to-cell disassembly, discharge state characterization measurements, and material analysis of its components based on x-ray fluorescence (XRF) and diffraction (XRD).
6
Ikezawa, S., e T. Ueda. "Basic Research on Elemental and Size Analytical System for Nano-Sized Suspended Particulate Matter Using Contactless Optical Measurement Techniques". International Journal of Measurement Technologies and Instrumentation Engineering 3, n. 1 (gennaio 2013): 16–27. http://dx.doi.org/10.4018/ijmtie.2013010102.
Testo completoAbstract (sommario):
A contactless sensing system for nano-sized carbonaceous particulate matter using laser-induced incandescence (LII) and laser-induced breakdown spectroscopy (LIBS) is presented. The LIBS technique allows detecting elemental composition and density of the SPMs, and LII technique allows to measure particulate size. LII technique is temporal resolved method that enables measurement of soot particulate sizes in a combustion process. In the case of the measured material consisting of a carbonaceous element, it is easy to determine the particulate diameter distribution derived from the time-profile of emission attenuation signals during cooling process, because the cooling behaviour is characteristic of the particulate diameter in LII technique. However, in actuality, the SPMs consist of several different types of elements. By using LIBS technique, the elemental analysis is able to conduct easily.
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Liu, Changcheng, Kaihui Zheng, Yong Zhou, Kai Zhu e Que Huang. "Experimental Thermal Hazard Investigation of Pressure and EC/PC/EMC Mass Ratio on Electrolyte". Energies 14, n. 9 (27 aprile 2021): 2511. http://dx.doi.org/10.3390/en14092511.
Testo completoAbstract (sommario):
Electrolytes are involved in the thermal runaway (TR) process of cells, which is a potential hazard in lithium-ion batteries (LIBs). Therefore, the effects of different mass ratio of carbonate solvents (ethylene carbonate (EC)/propylene carbonate (PC)/ethyl methyl carbonate (EMC)) with LiBF4 and different environmental pressure on the combustion characteristics of electrolyte such as flame centerline temperature, mass loss rate (MLR) and heat release rate (HRR) were analyzed. The combustion process could be divided into four stages: ignition, stable combustion stage, stable combustion with flame color change stage and extinguishing; with the decrease of pressure, the MLR of electrolyte declined and the combustion time prolonged, while the temperature of flame centerline increased.
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Niu, Xiaofeng, Yunfeng Li, Yanjie Hu, Hao Jiang, Xiaoyu Hou, Wenge Li, Shengjie Qiu e Chunzhong Li. "Aerosol construction of multi-shelled LiMn2O4 hollow microspheres as a cathode in lithium ion batteries". New Journal of Chemistry 40, n. 2 (2016): 1839–44. http://dx.doi.org/10.1039/c5nj02501j.
Testo completoAbstract (sommario):
Novel multi-shelled LiMn2O4 hollow microspheres have been successfully prepared by a facile aerosol spray pyrolysis route through the controlled combustion of carbon species. These microspheres show a superior specific capacity and a good rate capacity in LIBs.
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Cao, Zhiqin, e Chengyang Zuo. "Cr2O3/carbon nanosheet composite with enhanced performance for lithium ion batteries". RSC Advances 7, n. 64 (2017): 40243–48. http://dx.doi.org/10.1039/c7ra06188a.
Testo completoAbstract (sommario):
A Cr2O3/carbon nanosheet composite is directly synthesized by solution combustion synthesis using chromium nitrate as the chromium source and glucose as the carbon source. As anode materials for LIBs, the composite shows superior performance than pure Cr2O3.
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Ghiji, Mohammadmahdi, Vasily Novozhilov, Khalid Moinuddin, Paul Joseph, Ian Burch, Brigitta Suendermann e Grant Gamble. "A Review of Lithium-Ion Battery Fire Suppression". Energies 13, n. 19 (1 ottobre 2020): 5117. http://dx.doi.org/10.3390/en13195117.
Testo completoAbstract (sommario):
Lithium-ion batteries (LiBs) are a proven technology for energy storage systems, mobile electronics, power tools, aerospace, automotive and maritime applications. LiBs have attracted interest from academia and industry due to their high power and energy densities compared to other battery technologies. Despite the extensive usage of LiBs, there is a substantial fire risk associated with their use which is a concern, especially when utilised in electric vehicles, aeroplanes, and submarines. This review presents LiB hazards, techniques for mitigating risks, the suppression of LiB fires and identification of shortcomings for future improvement. Water is identified as an efficient cooling and suppressing agent and water mist is considered the most promising technique to extinguish LiB fires. In the initial stages, the present review covers some relevant information regarding the material constitution and configuration of the cell assemblies, and phenomenological evolution of the thermal runaway reactions, which in turn can potentially lead to flaming combustion of cells and battery assemblies. This is followed by short descriptions of various active fire control agents to suppress fires involving LiBs in general, and water as a superior extinguishing medium in particular. In the latter parts of the review, the phenomena associated with water mist suppression of LiB fires are comprehensively reviewed.
Tesi sul tema "Combustion LIBS"
1
Girardello, Carlo. "Optical Analysis of Plasma : Flame Emission in Cryogenic Rocket Engines". Thesis, Luleå tekniska universitet, Rymdteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-76097.
Testo completoAbstract (sommario):
This thesis contains the results of optical flame emission measurements of the Vulcain 2.1engine and the plasma emission spectroscopy of the Lumen Project engine. The plume spectroscopyis analyzed, ordered and studied in detail to offer the best possible molecular composition.The main focus relied on the hydroxide radical, blue radiation and other moleculesanalysis of the intensities encountered during the tests. The plasma emission spectroscopy isfocused on the determination of the plasma temperature value in LIBS measurements. Thehydrogen plasma temperature determination of the local thermodynamic equilibrium, followedby the carbon and sequentially oxygen plasma is obtained. The quality of the LTE isto be determined to judge the truthworthness of the determined temperatures. Both the testsare analyzed thanks to the use of spectrographs, cameras and dedicated software for opticalapplications. The results related to the Vulcain 2.1 LOX/LH2 engine showed the evolutionof the plume in different ROF or pressure variations. Furthermore, the results of the LumenProject LOX/methane engine led to the determination of the plasma temperatures and a firstestimation of the LTE quality.Die vorliegende Arbeit präsentiert die Ergebnisse der Abgasstrahlspektroskopie des H2/LOXVulcain 2.1 Triebwerks und der Zündplasma Spektroskopie des CH4/LOX Triebwerks desLUMEN Projektes. Die Abgasstrahlspektroskopie wurde analysiert und im Detail untersuchtum die am besten passende molekulare Zusammensetzung herauszuarbeiten. DasHauptaugenmerk liegt dabei auf dem Hydroxyl- Radikal, der Blauen Strahlung und molekularerIntensitätsanalyse. Bei der Zündplasmaanalyse liegt der Fokus auf der Bestimmungdes LTE Zustands (Lokales thermodynamisches Gleichgewicht) in LIBS. Die Temperaturdes Wasserstoff-, Kohlenstoff und Sauerstoffplasmas wird herangezogen, um die Qualitätdes LTE Zustands zu beurteilen. Für die Testdurchführung wurden Spektrographen, Kamerasund bestimmte Auswertungstools für optische Anwendungen benutzt. Das Verhaltendes Vulcain 2.1 Abgasstrahls abhängig von verschiedenen ROF und Druckstufen ist in denErgebnissen beschrieben. Für das LUMEN Triebwerk konnten erste Zündplasmatemperaturenbestimmt werden und geben einen Rückschluss auf die Qualität des LTE.
2
D'Angelo, Yves. "Analyse et simulation numérique de phénomènes liés à la combustion supersonique". Phd thesis, Ecole Nationale des Ponts et Chaussées, 1994. http://pastel.archives-ouvertes.fr/pastel-00568711.
Testo completoAbstract (sommario):
Analyse et simulation numérique d'écoulements supersoniques réactifs. Étude de la stabilisation d'une flamme par effet Mach au sein d'un écoulement air-hydrogène prémélangé bidimensionnel. Analyse phénoménologique des conditions d'allumage et de stabilisation d'une flamme à l'aval d'un système stationnaire d'ondes de choc ; cette analyse montre qu'il faut tenir compte de la réaction chimique dans la structure considérée. Exploration de méthodes de résolution des équations de la cinétique chimique complexe explosive air-hydrogène ; analyse de la stabilité de ces méthodes.
3
Angelo, Yves d'. "Analyse et simulation numérique de phénomènes liés à la combustion supersonique". Marne-la-vallée, ENPC, 1994. http://www.theses.fr/1994ENPC9425.
Testo completoAbstract (sommario):
L’objet de ce travail concerne l'analyse et la simulation numérique d'écoulements supersonique réactifs. Dans une première partie, on étudie la stabilisation d'une flamme par effet de mach au sein d'un écoulement air-hydrogène prémélange bidimensionnel. On présente d'abord une analyse phénoménologique des conditions d'allumage et de stabilisation d'une flamme à l'aval d'un système stationnaire d'ondes de chocs. Cette étude montre qu'il est nécessaire de tenir compte de la réaction chimique dans la structure considérée. On explore ensuite la stabilité de quelques méthodes implicites et linéairement implicites pour la résolution des équations de la cinétique chimique complexe explosive air-hydrogène, et on effectue également l'analyse de stabilité de tels schémas dans des cas simplifiés, montrant en particulier leur inadéquation pour des cinétiques rapides et trop fortement exothermiques. Pour des simulations stationnaires ou instationnaires, on adopte une méthode à pas fractionnaires fondée d'une part sur un solveur de Riemann multi-espèces explicite du deuxième ordre, en volumes finis non structurés, et d'autre part sur un solveur spécialisé pour la chimie, tel que Limex ou lsode. On termine cette partie par quelques résultats de simulations bidimensionnelles, pour une combustion air-hydrogène avec cinétique complexe et loi d'état réaliste. Le deuxième volet aborde l'étude des phénomènes de transports diffusif et turbulent. La méthode de résolution des équations de Navier-Stokes laminaires est fondée sur une formulation volumes finis structurés. Le deuxième ordre est atteint par le schéma T. V. D. De Harten, qui se rapporte identiquement au flux de Roe au premier ordre. Pour accélérer la convergence vers un état stationnaire, on utilise un schéma implicite linéarisé. L’inversion du système linéaire résultant s'effectue grâce à une méthode de Gauss-Seidel par lignes. Le terme source chimique fait l'objet d'un traitement particulier, visant à conserver des propriétés de positivité des valeurs propres des matrices jacobiennes intervenant dans l'implication. Les effets de la turbulence sont pris en compte par un modèle k-epsilon, et l'interaction cinétique chimique-turbulence par une approche en densité de probabilité présumée en température. Des essais numériques sont alors effectués d'abord dans quelques situations académiques, en particulier pour une couche de mélange compressible à masse volumique fortement variable. On termine par des comparaisons avec des résultats de la littérature de couche de mélange réactive air-hydrogène, ainsi qu'une expérience de combustion supersonique.
4
Schreiber, Didier. "Quelques problèmes de combustion lies à l'allumage dans les moteurs fusée cryotechniques". Châtenay-Malabry, Ecole centrale de Paris, 1991. http://www.theses.fr/1991ECAP0204.
Testo completoAbstract (sommario):
Ce travail porte sur certains problèmes de combustion lies à l'allumage dans les moteurs fusée cryotechniques. Dans les conditions nominales de fonctionnement de ces moteurs, la combustion peut être de type prémélangée (les réactifs se mélangent avant de réagir) ou non-prémélangée. L'allumage se produit par la rencontre entre des gaz chauds et un prémélange partiel, sous la forme d'éléments de flamme. Après la propagation de la flamme vers les injecteurs, les flammes de prémélange disparaissent et des flammes non prémélangées s'établissent dans la cavité. Les chapitres II et III ont été consacrés a l'étude théorique et expérimentale de flammes laminaires prémélangées. Les résultats des calculs concernent des flammes de prémélange et de diffusion et permettent de cerner les domaines de richesse, pression et taux d'étirement ou l'allumage est envisageable. Des mesures spectroscopiques permettent de déterminer le comportement de flammes de méthane et d'hydrogène soumises à différentes conditions. Les trois derniers chapitres de cette thèse sont consacrés à la combustion turbulente, et plus particulièrement à la propagation de la flamme turbulente après l'allumage. On trouve au chapitre IV des rappels concernant plusieurs modélisations de la combustion turbulente dans les cas prémélangé et non-prémélangé. Le chapitre V donne les bases théoriques d'un nouveau modèle mixte destine à la description de la transition entre les deux types de combustion, et le chapitre VI donne une première validation de ce modèle en comparant des résultats expérimentaux avec ceux issus des calculs.
5
Aguillon, Martinez Javier. "Étude du comportement hydrodynamique des lits fluidisés circulants avec injection d'air secondaire". Compiègne, 1995. http://www.theses.fr/1995COMPD826.
Testo completoAbstract (sommario):
L'hydrodynamique du procédé de combustion de charbon dans un lit fluidisé circulant est étudiée. Cette étude vise, en particulier, l'effet de l'injection d'air secondaire sur le comportement de la suspension. Nous avons utilisé une installation pilote en similitude avec la centrale thermique de Carling (Lorraine, France). L'étude a mis en évidence l'existence de deux régimes hydrodynamiques séparés par une concentration critique de solide. La comparaison des diagrammes de régime, avec et sans air secondaire, a montré que cette concentration est unique dans les deux cas. La structure de l'écoulement diphasique a été étudiée au moyen d'une sonde de prélèvement non-isocinétique et d'une sonde à fibres optiques placées à trois niveaux de la colonne. La combinaison des techniques de prélèvement de solide et de mesure des vitesses de particules a permis de développer une méthode pour estimer la concentration locale de solide. L'étude des profils de flux massiques de solide a montré que la distribution des iso-flux dépend sensiblement de la vitesse superficielle du gaz. De plus, nous avons constaté que ces iso-flux sont indépendants de l'injection d'air secondaire. Par ailleurs, nous avons constaté que la configuration d'arrivée d'air secondaire dans la colonne, est très importante. Pour réduire l'influence de cette injection sur la structure de l'écoulement, il faut éviter la formation de jets au niveau de l'injection d'air secondaire. L'ensemble des informations obtenues dans cette étude, nous a permis de proposer des modèles de profils de flux massique et de concentration de solide sous forme de corrélations adaptées à une extrapolation industrielle.
6
Willman, Christopher. "Laser diagnostics for spatially resolved thermometry in combustion and flows". Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:fc0cbf95-302f-4de7-9212-6afa2632c93a.
Testo completoAbstract (sommario):
The development of Laser-Induced Thermal Grating Spectroscopy (LITGS) for diagnostics of combusting and non-combusting flows is described. The first use of LITGS to provide in situ calibration of 2-Dimensional temperature distributions generated using Two-Colour Planar Laser-Induced Fluorescence (TC-PLIF) is reported. Time-resolved measurements of temperature distributions in a firing GDI optical engine obtained by TC-PLIF were made during the compression stroke and calibrated to the absolute temperature scale by simultaneous LITGS measurements. The accuracy and precision of the temperatures derived from LITGS data are evaluated using alternative methods of data analysis - Fast Fourier Transform and Fitting to theoretical models of the experimental data. The relative merits of the two methods are examined for analysis of weak LITGS signals obtained under engine conditions of low pressure and high temperature. The combined TC-PLIF and LITGS system was demonstrated by performing repeated single-shot measurements for 1 in every 10 four-stroke cycles showing excellent correlation of the temperatures derived from both techniques. Direct measurement of the effect of 'charge cooling', of order 5 K, for operation with direct injection is reported. Inhomogeneous temperature distributions were observed during the compression stroke for fired operation with Port Fuel Injection (PFI) and also with Gasoline Direct Injection (GDI). The effects of varying the relative concentrations of toluene and iso-octane in the two-component fuel were investigated. Extension of the LITGS technique to multi-point measurements along a 1-D line is described. By recording signals from 4 points on separate detectors using a fibre-coupled photodiode array the limitations of Streak Cameras used previously for 1-D LITGS measurements were overcome. Demonstration of principle experiments are reported in which simultaneous 4-point measurements were made with 1 mm spatial resolution and a precision of 0.7 % in temperature gradients in gas flows and in boundary layers at surfaces.
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Silva, Caroline Santos da. "Produção e avaliação de materiais de referência para nutrientes e contaminantes inorgânicos em amostras agronômicas". Universidade Federal de São Carlos, 2016. https://repositorio.ufscar.br/handle/ufscar/7860.
Testo completoAbstract (sommario):
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
The intensive search for the reliability of results increases the role of reference materials, mainly in analytical chemistry, because they provide metrological references to ensure traceability of measurements and are still central to the validation of analytical methods. The increasing demand for new reference materials is gradual in all areas of knowledge, but the agricultural and food sectors are among the neediest. In Brazil, this requirement is met only by the import of the material at high costs, being frequently the lack of adequate material to the needs of the country. In this context, this work aimed at the production of reference material for inorganic nutrients and contaminants present in a phosphate rock, the raw material used to manufacture fertilizers. The material was produced by following the next steps, internationally established by ISO GUIDES 30 to 35: preparation and ackaging material, assessment of uniformity, stability test in short and long periods and in prior characterization that was the assembly of the collaborative trial, with the distribution of the prepared material to laboratories that were willing to collaborate with the project.Sample preparation studies also have been conducted, aimed at speed and reduced use of reagents. The evaluation of the estimated minimum mass, homogeneity, and stability of the material was performed using inductively coupled plasma optical emission spectrometry (ICP OES) as determination technique. Phosphorus determination was evaluated by laser-induced breakdown spectroscopy (LIBS).Analysis of single-factor variance (ANOVA) was applied to results and the homogeneity and stability of the material presented averages within the 95% confidence interval. The obtained resultsalong the prepare and with collaborative trialallowed the chemical characterization and the determinationof the uncertainties related to each stage of the preparation of the material, and final preparation of the chart control with results of the reference materialwith the expanded uncertainty for each of the analytes under study.Part of the work was developed by the National Research Council Canada (NRCC) in Ottawa in Canada.The applicability of the microwave-induced combustion for sample preparation of previously prepared national reference materials, bovine liver (RM-Agro E3001a) and forage (RM E1001a-Agro) was evaluated for the determination of As, Cd, Cu, and Pb by inductively coupled plasma mass spectrometry (ICP-MS), and the recults coulb be applied in other organic and inorganic materials.
A intensa busca por confiabilidade de resultados torna cada vez mais importante o papel dos materiais de referência, principalmente em química analítica, pois fornecem referências metrológicas visando assegurar a rastreabilidade de medições e ainda são fundamentais para a validação de métodos analíticos. O aumento da demanda por novos materiais de referência é gradativo em todas as áreas do conhecimento, porém os setores agropecuários e de alimentos estão entre os mais carentes. No Brasil, essa demanda é atendida somente pela importação do material a custos elevados, sendo freqüente a inexistência de materiais adequados às necessidades do país. Nesse contexto, o presente trabalho visou à produção de material de referência para nutrientes e contaminantes inorgânicos em fosfato de rocha, matéria-prima utilizada para a fabricação de fertilizantes. O material foi produzido seguindo as seguintes etapas, estabelecidas internacionalmente pelas ISO GUIAS 30 a 35: preparo e envase do material, avaliação da homogeneidade, teste de estabilidade a curto e a longos períodos e na caracterização prévia, que consistiu na montagem do ensaio colaborativo, com a distribuição do material preparado a laboratórios que se dispuseram a colaborar com o projeto. Ainda foram realizados estudos voltados ao preparo da amostra visando a rapidez e redução de uso de reagentes. A avaliação da estimativa da massa mínima, da homogeneidade e da estabilidade do material foi realizada utilizando-se como técnica de determinação a espectrometria de emissão óptica com plasma indutivamente acoplado (ICP OES). Para a determinação de fósforo foi avaliado o emprego de espectrometria de emissão com plasma induzida por laser (LIBS). Os resultadosforam submetidos à análise de variância e fator único (ANOVA) e a homogeneidade e a estabilidade do material apresentaram médias dentro do intervalo de confiança de 95%. Os resultados obtidos durante o preparo e através do ensaio colaborativo possibilitaram a caracterização química e o calculo das incertezas relativas a cada etapa do preparo do material, sendo elaborada a carta controle com os resultados do material de referência e as incertezas expandidas para cada um dos analitos em estudo. Parte do trabalho foi desenvolvido junto ao National Research Council Canada (NRCC) em Ottawa no Canadá, onde foi avaliada a aplicabilidade do sistema de combustão iniciada por radiação microondas no preparo de amostras de materiais de referência nacionais anteriormente preparados, fígado bovino (RM-Agro E3001a) e forrageira (RM-Agro E1001a), para a determinação de As, Cd, Cu e Pb por espectrometria de massas com plasma indutivamente acoplado (ICP-MS), sendo obtidos resultados que poderão ser aplicados em outros materiais orgânicos e inorgânicos.
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Kürthy, Marián. "Kogenerační jednotka s absorpčním TČ". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230314.
Testo completoAbstract (sommario):
This diploma work aims to evaluate the functional connection of the cogeneration unit with an internal combustion engine and an absorption heat pump to increase the heating effect of the cogeneration. The aim of this work is to design a functional system and evaluate it from the technical - economic terms. In the introduction of the theoretical work the applied cogeneration technologies used in combined heat and power production are presented. Then there is described the principle of heat pumps, their basic components and theoretical comparison of compression and absorption heat pumps. In the practical part of this work is for a specific application in the area Technická 2 proposed merger of the cogeneration unit with an internal combustion engine and an absorption heat pump, while detailed design parameters used in absorption heat circulation are set. At the end of this paper there are designed various heat exchangers of applied absorption heat pump. The final part of the work is devoted to technical - economic assessment of applied design. In this assestment three different types of heat pumps are compared: Absorption heat pump with working solution H2O-LiBR, absorption heat pump with working fluids NH3-H2O and compressor heat pump.
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Nouyrigat, Nicolas. "Hydrodynamic modeling of poly-solid reactive circulating fluidized beds : Application to Chemical Looping Combustion". Phd thesis, Toulouse, INPT, 2012. http://oatao.univ-toulouse.fr/9189/1/nouyrigat.pdf.
Testo completoAbstract (sommario):
This work deals with the development, validation and application of a model of Chemical Looping Combustion (CLC) in a circulating fluidized bed system. Chapter 1 is an introduction on Chemical Looping Combustion. It rst presents the most important utilizations of coal in the energy industry. Then, it shows that because of the CO2 capture policy, new technologies have been developed in the frame of post-combustion, pre-combustion and oxy-combustion. Then, the Chemical Looping Combustion technology is presented. It introduces multiple challenges: the choice of the Metal Oxide or the denition of the operating point for the fuel reactor. Finally, it shows that there are two specicities for CFD modeling: the influence of the collisions between particles of different species and the local production of gas in the reactor due to the gasication of coal particles. Chapter 2 outlines the CFD modeling approach: the Eulerian-Eulerian approach extended to flows involving different types of particles and coupled with the chemical reactions. Chapter 3 consists in the validation of the CFD model on mono-solid (monodisperse and poly-disperse) and poly-solid flows with the experimental results coming from an ALSTOM pilot plant based at the Universite Tchnologique de Compiegne (France). The relevance of modeling the polydispersity of a solid phase is shown and the influence of small particles in a CFB of large particles is characterized. This chapter shows that the pilot plant hydrodynamics can be predicted by an Eulerian-Eulerian approach. Chapter 4 consists in the validation of the CFD model on an extreme bi-solid CFB of particles of same density but whith a large particle diameter ratio. Moreover, the terminal settling velocity of the largest particles are twice bigger than the fluidization velocity: the hydrodynamics of the large particles are given by the hydrodynamics of the smallest. An experiment performed by Fabre (1995) showed that large particles can circulate through the bed in those operating conditions. Our simulations predicted a circulation of large particles, but underestimated it. It is shown that it can be due to mesh size eect. Finally, a simulation in a periodic box of this case was dened and allowed us to show the major influence of collisions between species. Chapter 5 presents the simulation of a hot reactive CLC pilot plant under construction in Darmstadt (Germany). The simulations account for the chemical reactions and describe its eect on the hydrodynamics. Different geometries and operating conditions are tested.
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Macé, Olivier. "Etude des champs de températures dans des écoulements hétérogènes : applications aux flammes de charbon pulverisé et aux lits fluidisés circulants". Rouen, 1989. http://www.theses.fr/1989ROUES032.
Testo completoAbstract (sommario):
Développement d'une méthode de mesure, basée sur l'émission-absorption du rayonnement thermique dans le proche infrarouge entre 1 et 5 microns, permettant de déterminer des valeurs ponctuelles sur toute l'épaisseur visée pour pouvoir établir les champs radiaux aussi bien qu'axiaux des températures et tester les modèles à deux dimensions
Libri sul tema "Combustion LIBS"
1
Succi, Sauro. Lattice Boltzmann for reactive flows. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780199592357.003.0026.
Testo completoAbstract (sommario):
The dynamics of reactive flows lies at the heart of several important applications, such as combustion, heterogeneous catalysis, pollutant conversion, pattern formation in biology and many others. In general, LB is well suited to describe reaction-diffusion applications with flowing species. This chapter provides the basic guidelines to include reactive phenomena within the LBE formalism. Reactive flows obey the usual fluid equations, augmented with a reactive source term, accounting for species transformations due to chemical reactions. Such term comes typically in the form of a polynomial product of the mass densities of the reacting species.
Capitoli di libri sul tema "Combustion LIBS"
1
Viskup, Richard, Christoph Wolf e Werner Baumgartner. "Qualitative Characterisation of Trace Elements in Diesel Particulate Matter from In-Use Diesel Engine Passenger Vehicles by Means of Laser-Induced Breakdown Spectroscopy". In Environmental Emissions. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.93067.
Testo completoAbstract (sommario):
In this research, we applied laser-plasma spectroscopy technique for the measurement of trace chemical elements in the exhaust emissions generated from in-use diesel engine passenger vehicles. We use high resolution laser-induced breakdown spectroscopy (LIBS) technique for diagnostics of soot and particulate matter (PM). Here we analysed soot and PM, extracted from exhaust manifold part, from different passenger vehicles that are used in daily life environment. The main aim of this study is to reveal the trace chemical elements in different PM matrices. The presence of trace elements in exhaust emissions can originate from different sources: from injected fuel type and fuel additives, engine lubricants, engine combustion process, incomplete catalytic reaction, inefficiency or wear out of PM filtering devices, dysfunctions or failures of engine or vehicle or even information related to polluted intake air.
Atti di convegni sul tema "Combustion LIBS"
1
Lee, T. W., N. Hegde e I. Han. "In-Situ Diagnostics of Combustion Parameters Using Laser-Induced Breakdown Spectroscopy". In ASME 2005 Summer Heat Transfer Conference collocated with the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems. ASMEDC, 2005. http://dx.doi.org/10.1115/ht2005-72517.
Testo completoAbstract (sommario):
Laser-Induced breakdown spectroscopy is a powerful diagnostic method that can be applied to combustion systems for measurements of fuel-air ratios, fuel composition, and temperature. In this study, we specifically show the application of LIBS for in-situ flame temperature measurements at conditions up to moderately sooting conditions (equivalence ratio of 15 for methane-air flames). Comparisons with existing data obtained from thermocouple exhibit excellent agreement in weakly sooting flames and good agreement at higher equivalence ratios. The deviation at higher equivalence ratios is attributed to signal trapping due to soot and precursor species and also due to increase in hydrogen spectral signal at these conditions. These are factors that can be circumvented and do not preclude application of LIBS to highly sooting flames.
2
Gupta, Sreenath B., Bipin Bihari, Munidhar Biruduganti e Raj Sekar. "In-Cylinder Equivalence Ratio Measurements in a EGR Equipped Engine". In ASME 2010 Internal Combustion Engine Division Fall Technical Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/icef2010-35072.
Testo completoAbstract (sommario):
A single-cylinder natural gas fueled engine equipped with a Exhaust Gas Recirculation (EGR) system was ignited using a laser. The broadband emission from the spark kernel was spectrally resolved and the peaks corresponding to Hα, N and O atoms were measured for a range of conditions with global equivalence ratios ranging between 0.6 and 1.0, and for Exhaust Gas Recirculation fractions up to 29%. The (Hα/O) and (Hα/N) peak intensity ratios from the spectral scans correlated extremely well (R2 > 0.97) with local oxygen based equivalence ratios. Appropriate relations were developed to relate such values to global equivalence ratios and the EGR rate. For homogenous intake charge, the present LIBS diagnostic enables estimation of one of the two values, global equivalence ratio or EGR rate, with the knowledge of the other.
3
Fischer, Stefan, David Kluß e Franz Joos. "Experimental Investigation of a Fuel Flexible Generic Gas Turbine Combustor With External Flue Gas Recirculation". In ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-25388.
Testo completoAbstract (sommario):
Flue gas recirculation in combined cycle power plants using hydrocarbon fuels is a promising technology for increasing the efficiency of the post combustion carbon capture and storage process. However, the operation with flue gas recirculation significantly changes the combustion behavior within the gas turbine. In this paper the effects of external flue gas recirculation on the combustion behavior of a generic gas turbine combustor was experimentally investigated. While prior studies have been performed with natural gas, the focus of this paper lies on the investigation of the combustion behavior of alternative fuel gases at atmospheric conditions, namely typical biogas mixtures and syngas. The flue gas recirculation ratio and the fuel mass flow were varied to establish the operating region of stable flammability. In addition to the experimental investigations, a numerical study of the combustive reactivity under flue gas recirculation conditions was performed. Finally, a prediction of blowout limits was performed using a perfectly stirred reactor approach and the experimental natural gas lean extinction data as a reference. The extinction limits under normal (non-vitiated) and flue gas recirculation conditions can be predicted well for all the fuels investigated.
4
Birkby, P., R. S. Cant, W. N. Dawes, A. A. J. Demargne, P. C. Dhanasekaran, W. P. Kellar, N. C. Rycroft, A. M. Savill, R. L. G. M. Eggels e I. K. Jennions. "CFD Analysis of a Complete Industrial Lean Premixed Gas Turbine Combustor". In ASME Turbo Expo 2000: Power for Land, Sea, and Air. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/2000-gt-0131.
Testo completoAbstract (sommario):
The introduction of lean premixed combustion technology in industrial gas turbines has led to a number of interesting technical issues. Lean premixed combustors are especially prone to acoustically-coupled combustion oscillations as well as to other problems of flame stability such as flashback. Clearly it is very important to understand the physics that lies behind such behaviour in order to produce robust and comprehensive remedies, and also to underpin the future development of new combustor designs. Simulation of the flow and combustion using Computational Fluid Dynamics (CFD) offers an attractive way forward, provided that the modelling of turbulence and combustion is adequate and that the technique is applicable to real industrial combustor geometries. The paper presents a series of CFD simulations of the Rolls-Royce Trent industrial combustor carried out using the McNEWT unstructured code. The entire combustion chamber geometry is represented including the premixing ducts, the fuel injectors and the discharge nozzle. A modified k-ε model has been used together with an advanced laminar flamelet combustion model that is sensitive to variations in fuel-air mixture stoichiometry. Detailed results have been obtained for the non-reacting flow field, for the mixing of fuel and air and for the combustion process itself at a number of different operating conditions. The study has provided a great deal of useful information on the operation of the combustor and has demonstrated the value of CFD-based combustion analysis in an industrial context.
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LYU, H. Y., e L. D. CHEN. "On the estimates of Li2S thermodynamic properties for prediction of Li-SF6 wick combustion". In 29th Joint Propulsion Conference and Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1993. http://dx.doi.org/10.2514/6.1993-2207.
Testo completo
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Lee, Wah-Keat, Kamel Fezzaa e Jin Wang. "X-Ray Propagation-Based Phase-Enhanced Imaging of Fuel Injectors". In ASME 2001 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/2001-ice-391.
Testo completoAbstract (sommario):
Abstract X-ray propagation-based phase-enhanced imaging is a powerful new technique that uses the x-ray beam coherence to greatly improve the image contrast. With the high x-ray beam brilliance (or alternately, good beam coherence) available at third-generation synchrotron sources, such as the Advanced Photon Source (APS), propagation-based phase-enhanced imaging can be easily accomplished. The power of this technique lies in its simplicity — it is an in-line geometry and requires little or no beam manipulation, and it works over the entire range of accessible energies (10–100 keV). Unlike conventional radiography, its contrast mechanism is mostly due to Fresnel diffraction and not absorption. The technique works for soft biological samples, as well as thick (several millimeters) stainless-steel samples. In this paper, we demonstrate the utility of this technique to study several fuel injectors and compare the results with conventional absorption radiography. The possibility of extending this technique to time-resolved imaging studies on the fuel injector will be discussed.
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LOUKHOVITSKI, B. I. "ON THE POSSIBILITY OF THE POST-TRANSITION STATE CLASSICAL TRAJECTORY PREDICTIONS OF ENERGY DEPOSITION IN THE REACTION PRODUCTS£ DEGREESOF FREEDOM". In 9th International Symposium on Nonequilibrium Processes, Plasma, Combustion, and Atmospheric Phenomena. TORUS PRESS, 2020. http://dx.doi.org/10.30826/nepcap9b-01.
Testo completoAbstract (sommario):
The possibility of applying the method of post-transition state classical trajectory dynamic simulations to study the nascent energy distribution among the molecular degrees of freedom of the reaction products is considered on the example of a number of bimolecular reactions. The results obtained for the energy deposition in the vibrational degrees of freedom of the reaction products are compared both with the reliable experimental and theoretical data. We show that the methodology under consideration gives, in principle, adequate estimates of the energy released into vibrations; however, slight discrepancies are observed, the nature of which lies in the methodological grounds of this approach.
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Manovic, Vasilije, e Borislav Grubor. "An Improved Model of Sulfur Self-Retention by Coal Ash During Coal Combustion in FBC". In 18th International Conference on Fluidized Bed Combustion. ASMEDC, 2005. http://dx.doi.org/10.1115/fbc2005-78020.
Testo completoAbstract (sommario):
During combustion of coal a significant amount of sulfur may be retained in ash due to the reactions between mineral matter in coal and sulfur oxides. This process is known as sulfur self-retention and its significance lies in the fact that a part of sulfur oxides, one of the main pollutants during combustion of coal, is not released in the atmosphere. Sulfur self-retention is influenced by parameters that depend on coal characteristics and combustion conditions. The interest for this process was enhanced with the introduction of fluidized bed combustion (FBC) technology since the temperatures and other conditions are favorable for sulfur self-retention. Investigation of this process, primarily modeling, is the subject of this work. The presented model is based on the previously developed model for the combustion of porous char particles under FBC conditions, along with a changing grain size model of sulfation of the CaO grains dispersed throughout the char particle volume. Incorporating the phenomena of sintering, reduction of the produced CaSO4 with CO, thermal decomposition of the produced CaSO4, as well as allowing for the different reactivity of various forms of calcium make major improvements of the model. A temperature dependent relation for the CaO grain radius takes sintering into account. Reductive and thermal decomposition were taken into account by the corresponding reaction rate constants of the Arrhenius type. The reactivity of the calcium forms in coal was considered by different initial radius of the CaO grains. The model was verified by the experimental results of sulfur self-retention of three Serbian coals during combustion in a fluidized bed combustion reactor. The comparison with the experimentally obtained results showed that the model can adequately predict the levels of the obtained values of sulfur self-retention efficiencies, as well as the influence of temperature, coal type and coal particle size.
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Luers, A., A.-L. Sahlberg, F. Förster, C. Willman, J. Camm, R. Stone, B. Williams e P. Ewart. "High precision measurement of combustion parameters in flames and engines using Laser Induced Grating Scattering, LIGS". In Optics and Photonics for Energy and the Environment. Washington, D.C.: OSA, 2017. http://dx.doi.org/10.1364/ee.2017.eth2a.2.
Testo completo
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Despierre, Arnaud, Peter J. Stuttaford e Philip A. Rubini. "Preliminary Gas Turbine Combustor Design Using a Genetic Algorithm". In ASME 1997 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/97-gt-072.
Testo completoAbstract (sommario):
A genetic algorithm, coupled with a versatile preliminary design tool, is employed to demonstrate the concept of an autonomous design procedure for gas turbine combustors with user specified performance criteria. The chosen preliminary design program utilises a network based approach which provides considerable geometric flexibility allowing for a wide variety of combustor types to be represented. The physical combustor is represented by a number of independent, though interconnected, semi-empirical sub-flows or elements. A full conjugate heat transfer model allows for convection, conduction and radiative heat transfer to be modelled and a constrained equilibrium calculation simulates the combustion process. The genetic algorithm, whose main advantage lies in its robustness, uses the network solver in order to progress towards the optimum design parameters defined by the user. The capabilities of the genetic program are demonstrated for some simple design requirements, for example zone fuel/air ratio, pressure drop and wall temperatures.