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Sample records for degainage des combustibles

  1. Combustion of Solid Propellants (La Combustion des Propergols Solides)

    Science.gov (United States)

    1991-07-01

    Programme Abrege Lhistoire des propergols solides a connu un bouleversement profond avec la d~eouve:te pal Paul Vieille et Nobel, t la fin du dix...material Here again, double base and composite is not homogeneous, the flame front is not propellant behaviour will be analysed and plane. The web thickness... web in the aft regions) the propellant will all) propellants, there is a minimum cross- burn out unevenly, leading to a long pres- flow velocity below

  2. Combustion chemistry and formation of pollutants; Chimie de la combustion et formation des polluants

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    This book of proceedings reports on 7 papers on combustion chemistry and formation of pollutants presented during the workshop organized by the `Combustion and Flames` section of the French society of thermal engineers. The chemistry of combustion is analyzed in various situations such as: turbojet engines, spark ignition engines, industrial burners, gas turbines etc... Numerical simulation is used to understand the physico-chemical processes involved in combustion, to describe the kinetics of oxidation, combustion and flame propagation, and to predict the formation of pollutants. (J.S.)

  3. L'évolution des combustibles pour moteurs thermiques Evolution of Fuels for Thermal Engines

    Directory of Open Access Journals (Sweden)

    Balaceanu J. C.

    2006-11-01

    Full Text Available Depuis la crise pétrolière, l'accroissement des prix et les craintes de pénurie ont conduit à adapter les moteurs aux combustibles disponibles. Si la situation apparaît comme moins tendue, l'industrie des machines thermiques, qui pendant longtemps a eu comme partenaire une industrie du pétrole très sûre, se trouve cependant confrontée à un marché des combustibles incertain dans son ravitaillement et surtout dans ses prix. Les progrès des moteurs diesel et des turbines à gaz, dûs à une meilleure adaptation à leur usage et aussi à l'évolution de la technologie, supposent que les combustibles n'apporteront aucune contrainte majeure en quantité ou en qualité. La modification des usages dévolus désormais au pétrole entraînera une réduction de la coupe lourde et un raffinage plus profond des bruts avec en particulier un développement du craquage catalytique et de la viscoréduction. Or, ces différentes opérations de conversion peuvent conduire à une détérioration de la qualité des combustibles moins grave pour le gazole que pour le fuel lourd. Dans les différents domaines impliqués, les parades technologiques sont en cours de développement. L'industrie des machines thermiques, qui poursuit l'amélioration des engins, et l'industrie du pétrole, qui recherche une réduction des prix des combustibles, sont donc conduites à un compromis optimal auquel elles ne peuvent accéder efficacement qu'en définissant les règles du jeu c'est-à-dire des spécifications internationales rigoureuses des combustibles. Since the oil crisis, the increase in prices and fears of a shortage have led to the adapting of engines to what fuels are available. Whereas the situation now seems somewhat less tense, the thermal machinery industry, which for a long time had a very reliable petroleum industry as its partner, nonetheless finds itself confronted with an uncertain fuel market with regard to supplies and especially to prices. Progress

  4. Large eddy simulation and combustion instabilities; Simulation des grandes echelles et instabilites de combustion

    Energy Technology Data Exchange (ETDEWEB)

    Lartigue, G.

    2004-11-15

    The new european laws on pollutants emission impose more and more constraints to motorists. This is particularly true for gas turbines manufacturers, that must design motors operating with very fuel-lean mixtures. Doing so, pollutants formation is significantly reduced but the problem of combustion stability arises. Actually, combustion regimes that have a large excess of air are naturally more sensitive to combustion instabilities. Numerical predictions of these instabilities is thus a key issue for many industrial involved in energy production. This thesis work tries to show that recent numerical tools are now able to predict these combustion instabilities. Particularly, the Large Eddy Simulation method, when implemented in a compressible CFD code, is able to take into account the main processes involved in combustion instabilities, such as acoustics and flame/vortex interaction. This work describes a new formulation of a Large Eddy Simulation numerical code that enables to take into account very precisely thermodynamics and chemistry, that are essential in combustion phenomena. A validation of this work will be presented in a complex geometry (the PRECCINSTA burner). Our numerical results will be successfully compared with experimental data gathered at DLR Stuttgart (Germany). Moreover, a detailed analysis of the acoustics in this configuration will be presented, as well as its interaction with the combustion. For this acoustics analysis, another CERFACS code has been extensively used, the Helmholtz solver AVSP. (author)

  5. Contrôle de combustion en transitoires des moteurs à combustion interne

    OpenAIRE

    Hillion, Mathieu

    2009-01-01

    This thesis addresses the problem of combustion control for automotive engines. A method is proposed to complement existing controllers, which uses look-up tables based on steady-state operation. During transients, the new control method adjusts fast control variables (ignition or injection time) to compensate for deviations in the cylinder initial conditions from their optimal values due to the inherent slow processes involved. The necessary adjustments are determined from a sensitivity anal...

  6. Les piles à combustible. Bilan des travaux de recherches. Perspectives Fuel Cells. Review of Research. Outlook

    Directory of Open Access Journals (Sweden)

    Breelle Y.

    2006-11-01

    Full Text Available Cet article fait le point, sous forme résumée, des travaux de recherches et de développement menés par l'Institut Français du Pétrole (IFP depuis vingt ans dans le domaine des piles à combustible : sélection des filières directes conduisant au choix de la pile hydrogène-air basse température à électrolyte basique, mise au point des générateurs à hydrogène alimentés en méthanol. On présente les résultats obtenus et les conclusions des enquêtes effectués dans le domaine des groupes électrogènes et des applications spéciales, dans celui de la traction automobile et dans celui de la production massive d'électricité. This article reviews and sums up the research and development done by Institut Français du Pétrole (IFP in the last 20 years in the field of fuel cells, including the selection of direct methods leading to the choice of low-temperature basic-electrolyte hydrogen/air cells and the development of methanol-powered hydrogen generators. The results obtained are desceibed along with the conclusions of surveys made in the field of electric generators and special applications in the fields of automotive traction and massive electricity production.

  7. Croissance des HAP et des suies et transition phase gaz-phase solide dans les processus de combustion

    Directory of Open Access Journals (Sweden)

    Mercier X.

    2012-01-01

    Full Text Available This article is addressed to a scientific community familiar to astrophysics, and most researchers are not familiar with combustion science. Thus the goal is to provide a basic understanding of “the flame” and the different steps that lead to soot particle formation in conditions that are generally close to atmospheric pressure and high temperature, i.e. in conditions far from those encountered in most astrophysical media. Some experimental techniques of sooty flame investigations will also be introduced. The main aim is to outline the concepts and the tools of combustion science to facilitate fruitful scientific exchanges between two communities that are motivated by the understanding of the formation and evolution of PAHs and soot-like particles, in completely different environments. It should be noted that the description does not pretend to be exhaustive at all and certain theoretical and experimental approaches are not described nor even mentioned. Résumé. Cet article s’adresse à une communauté « astrophysique » non familière avec la combustion. Il a pour but de donner quelques bases permettant de comprendre « la flamme » et les étapes chimiques principales conduisant à la formation de particules de suie dans un milieu généralement à pression atmosphérique et haute température, c’est-à-dire dans des conditions de pression et température très éloignées de celles rencontrées dans le milieu interstellaire. Certaines méthodes expérimentales d’investigation de flammes suitées sont également présentées. L’objectif étant de pouvoir jeter des ponts entre deux communautés éloignées mais rassemblées par un même intérêt pour les hydrocarbures aromatiques polycycliques et les particules de suie. Il est clair que la présentation qui est faite ici est très succincte et qu’elle fait l’impasse sur certaines théories, approches, méthodes expérimentales…

  8. Recent developments in the field of refractory fuels; Developpements recents dans le domaine des combustibles refractaires

    Energy Technology Data Exchange (ETDEWEB)

    Accary, A.; Delmas, R. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    .e. sintering or arc fusion). This latter method is based on fusion by electronic bombardment associated with the continuous casting. (authors) [French] L'effort des recentes annees au Commissariat a l'Energie Atomique dans le domaine des combustibles ceramiques a surtout porte sur le bi-oxyde d'uranium et les alliages uranium-carbone. Le bi-oxyde d'uranium est etudie dans l'optique de son utilisation comme combustible de la premiere charge d'EL 4, dans laquelle on impose au point le plus charge une conductibilite thermique integree de 29 W/cm pour une temperature de surface de 750 C environ. On s'est specialement preoccupe de mettre en place un procede de preparation d'une poudre de bi-oxyde de bonnes caracteristiques et le frittage industriel de cette poudre, et d'evaluer les principales proprietes des corps obtenus en relation avec les conditions des corps obtenus en relation avec les conditions prevues de leur utilisation: - aspect de micro-structure et distribution des pores, - comportement mecanique et thermique en geometrie cylindrique, - controle de l'oxygene excedentaire dans les produits industriels, - compatibilite aux hautes temperatures avec les oxydes utilisables comme isolants thermiques, - comportement des produits de fission gazeux a haute temperature apres irradiation ou au cours de l'irradiation. Dans le cas des carbures d'uranium, notre but a ete de determiner les conditions de fabrication industrielle d'un combustible satisfaisant de composition voisine de UC. Ceci nous a conduits a entreprendre un certain nombre d'etudes fondamentales Sur le domaine d'existence de UC non stoechiometrique, - l'influence, sur les proprietes de UC, des elements O et N dissous dans ce materiau, - la compatibilite des alliages uranium-carbone avec differents materiaux de gaine metalliques ou ceramiques, - la corrosion des alliages uranium-carbone par H{sub 2}O et CO{sub 2}, - les methodes de

  9. Les méthodes thermiques de production des hydrocarbures. Chapitre 5 : Combustion "in situ". Pricipes et études de laboratoire Thermal Methods of Hydrocarbon Production. Chapter 5 : "In Situ" Combustion. Principles and Laboratory Research

    Directory of Open Access Journals (Sweden)

    Burger J.

    2006-11-01

    Full Text Available II existe plusieurs variantes de la combustion in situ, suivant le sens de déplacement du front de combustion, à co-courant ou à contre-courant, et suivant la nature des fluides injectés, air seul ou injection combinée d'air et d'eau. Les réactions de pyrolyse, d'oxydation et de combustion mises en jeu par ces techniques sont discutées, en particulier la cinétique des principaux mécanismes réactionnels, l'importance du dépôt de coke et l'exothermicité des réactions d'oxydation et de combustion. Les résultats d'essais de déplacement unidirectionnel du front de combustion dans des cellules de laboratoire sont présentés et discutés. Enfin on indique les conditions pratiques d'application des méthodes de combustion in situ sur champ. Possible variations of in situ combustion technique ore as follows : forward or reverse combustion depending on the relative directions of the air flow and the combustion front, dry combustion if air is the only fluid injected into the oil-bearing formation, or fixe/woter flooding if water is injected along with air. The chemical reactions of pyrolysis, oxidation and combustion involved in these processes are described. The kinetics of these reactions is discussed as well as fuel availability in forward combustion and the exothermicity of the oxidation and combustion reactions. The results obtained in the laboratory when a combustion front propagates in unidirectional adiabatic tells are described and discussed. This type of experimentation provides extensive information on the characteristics of the processes. Screening criteria for the practical application of in situ combustion techniques are presented.

  10. Combustion

    CERN Document Server

    Glassman, Irvin

    1987-01-01

    Combustion, Second Edition focuses on the underlying principles of combustion and covers topics ranging from chemical thermodynamics and flame temperatures to chemical kinetics, detonation, ignition, and oxidation characteristics of fuels. Diffusion flames, flame phenomena in premixed combustible gases, and combustion of nonvolatile fuels are also discussed. This book consists of nine chapters and begins by introducing the reader to heats of reaction and formation, free energy and the equilibrium constants, and flame temperature calculations. The next chapter explores the rates of reactio

  11. Étude de la carbonatation et de l'hydratation des membranes alcalines solides dans les piles à combustibles

    Science.gov (United States)

    Tronel, F.; Gautier, L.; Brincourt, T.; Sandré, E.

    2002-04-01

    Les piles à combustible alcalines sont des systèmes performants qui fonctionnent à température ambiante et nécessitent moins de métaux précieux (platine) que les piles à combustible à membrane protonique (PEMFC). Des études approfondies concernant la synthèse de membranes alcalines à base d'oxyde de polyéthylène (PEO) ou d'Epichlorhydrine (EpCI) ont montré que ces matériaux présentent des conductivités ioniques du même ordre de grandeur que les membranes Nafion^{circledR}. Les problèmes inhérents à ces technologies sont l'hydratation des membranes (comme pour les PEMFC) et leur sensibilité au CO2 par précipitation d'ions carbonates en présence de KOH (carbonatation). La première partie de l'étude concerne la détermination des caractéristiques importantes d'une membrane copolymère PEO-EpCI (conductivité et gonflement). Dans un deuxième temps, le profil de concentration en eau dans une pile en régime stationnaire a été évalué après détermination expérimentale de quelques paramètres physiques (coefficient de diffusion de l'eau, concentration limite). Le problème de la carbonatation est abordé à partir des équations chimiques de formation des ions carbonates. Le profil permet de rendre compte du problème d'assèchement et de précipitation du carbonate de potassium à proximité des électrodes.

  12. Combustibles des ménages et modes d'utilisation à l'échelle du ...

    African Journals Online (AJOL)

    Pour ce faire, à l'échelle du terroir de Vipalogo, 30 exploitations ont été retenues au hasard, et enquêtées sur les combustibles énergétiques utilisés. Des mesures de consommation de combustibles ont aussi été menées régulièrement à trois périodes de l'année, période froide et sèche, saison sèche et chaude et en ...

  13. Ignition et oxydation des particules de combustible solide pulvérisé Ignition and Oxidation of Pulverized Solid Fuel

    Directory of Open Access Journals (Sweden)

    De Soete G. G.

    2006-11-01

    Full Text Available On présente dans cet article, en utilisant la méthode du ruban chauffé, une étude de la compétition entre (1 la dévolatilisation et l'oxydation consécutive des produits de pyrolyse et (2 l'ignition de la matrice solide et sa combustion rapide. La comparaison entre le moment de l'ignition et le début de la pyrolyse permet de déterminer en fonction de la température, de la taille des particules et de la concentration en oxygène, le domaine dans lequel l'ignition d'un combustible solide pyrolysable est du type whole coal ignition (c'est-à-dire lorsque l'ignition intervient avant que la pyrolyse devienne mesurable. Les résultats suggèrent que ce type d'ignition doit s'effectuer en règle générale dans les conditions de mise en oeuvre des combustibles solides pulvérisés dans les flammes industrielles. Dans le cas de l'ignition whole coal , la vitesse de combustion de la matrice solide est inhibée dans la période qui suit l'ignition. Cette inhibition est due d'une part à la difficulté pour l'oxygène de diffuser dans les pores pendant la sortie des produits de pyrolyse, et d'autre part à la consommation préférentielle de l'oxygène dans l'oxydation des produits de pyrolyse, principalement dans le cas où cette oxydation se développe sous forme de flamme. Ce n'est que lorsque la pyrolyse s'achève que la vitesse de combustion hétérogène peut atteindre sa valeur stationnaire normale, qui est alors pratiquement identique à celle du coke. Aux températures situées entre la température d'ignition du combustible solide et la température d'extinction du coke résiduel, la combustion est incomplète, une extinction intervenant à un degré de dévolatilisation d'autant plus grande que la température est élevée. Ce phénomène s'explique qualitativement par la théorie classique d'ignition thermique lorsqu'on l'applique au cas particulier des combustibles solides pyrolysables. Les températures d'ignition ainsi que les d

  14. Optical Engines as Representative Tools in the Development of New Combustion Engine Concepts Moteurs transparents comme outils représentatifs dans le développement de nouveaux concepts des moteurs à combustion interne

    Directory of Open Access Journals (Sweden)

    Kashdan J.

    2011-11-01

    (EGR. A comparison has been made between simulated EGR (using pure nitrogen with real EGR under Diesel LTC conditions. Finally, “pure”, single component fuels are often employed in optical Diesel engines due to laser diagnostic constraints. However, these fuels generally differ from standard Diesel fuel in terms of cetane number and fuel volatility which can significantly influence the combustion and emissions characteristics in optical engines. These aspects have also been investigated within the present study. An improved understanding of the differences between optical and all-metal engines has allowed us to develop appropriate strategies to compensate for these differences on the optical engine. It is shown here that combustion phasing (and engine-out emissions matching between optical and all-metal engines can be achieved even for advanced LTC Diesel combustion strategies. The ability to ensure fully representative combustion and emissions behaviour of optical engines ultimately increases the value of optical engine data, highlighting the importance of using such engines as research tools for the further development of innovative, low emission combustion concepts. Les moteurs monocylindres transparents sont employés comme outils de recherche et de développement des moteurs à combustion interne. Ils permettent l’utilisation de techniques de diagnostics non-intrusifs (qualitatifs et quantitatifs pour étudier des phénomènes comme l’aérodynamique interne, la préparation du mélange, la combustion et la formation de polluants. Ces données expérimentales sont importantes pour la validation des modèles numériques et permettent également d’obtenir une compréhension détaillée des phénomènes physiques se déroulant dans la chambre. Les données recueillies aident au développement des nouvelles stratégies de combustion telles que la combustion homogène (HCCI et la combustion Diesel à basse température (LTC. Dans ce contexte, il est important

  15. Environmental Impact of Munition and Propellant Disposal (Impact Environnemental de l’Elimination des Munitions et des Combustibles)

    Science.gov (United States)

    2010-02-01

    sur les sujets critiques. La présence de scientifiques du domaine de la recherche et de personnels militaires à généré des débats très satisfaisants à...questions critiques auxquelles les nations de l’OTAN sont confrontés, pour rechercher les meilleures pratiques actuelles et identifier les contraintes... sur l’environnement. La réunion a inclus des participants provenant de

  16. Ameliorer les performances environnementales des centrales a charbon pulverise via la co-combustion de combustible derive de dechets

    Science.gov (United States)

    Vekemans, Odile Geraldine

    Coal supplies around 28% of the world's energy needs and produces some 40% of the world's electricity. In the United States, close to 650 coal power plants currently produce electricity from coal, the majority of witch are equipped with pulverized coal boilers build in the 80's. Due to coal's intrinsic content in nitrogen and sulfur, its combustion is associated with high levels of NOx and SO2 emissions, that are responsible, among other thing, for acid rains. In order to help reduce SO2 emissions of coal power plant, this thesis focuses on the behaviour of a novel feedstock called ReEF(TM) or ReEngineered Feedstock(TM), developed by the company Accordant Energy LLCRTM, that combines non recyclable waste and alkaline sorbent. Since waste have a high calorific value and do not contain sulfur, and since alkaline sorbents (such as limestone) are able to react with SO2 and capture it in solid state, co-combustion of ReEF(TM) and coal could reduce SO2 emissions inside the furnace chamber itself. This technology easy to implement, as it requires a limited initial investment and limited additional space, could help avoid the construction of costly flue gas treatment unit downstream from the furnace. However, careless combustion of this engineered fuel could have disastrous consequences for the coal power plant owners. This thesis, then, deliver one among the first experimental study of co-combustion of coal and ReEF(TM) in conditions characteristic of pulverized coal boilers. As a first step, in order to get familiarize with the feedstock under study, the thermal degradation of a ReEF(TM) without sorbent and of its components is analyzed by thermogravimetry. With the analysis of more than 70 samples at heating rates ranging from 5°C/min to 400°C/min we are able to conclude that ReEF(TM) thermal degradation can be seen as the independent thermal degradation of its components, as long as heat transfer limitations are taken into account. Thus, no substantial chemical

  17. Cfd Based Shape Optimization of Ic Engine Optimisation de l'admission et des chambres de combustion des moteurs avec la modélisation 3D

    Directory of Open Access Journals (Sweden)

    Griaznov V.

    2006-12-01

    Full Text Available Intense competition and global regulations in the automotive industry has placed unprecedented demands on the performance, efficiency, and emissions of today's IC engines. The success or failure of a new engine design to meet these often-conflicting requirements is primarily dictated by its capability to provide minimal restriction for the inducted and exhausted flow and by its capability to generate strong large-scale in-cylinder motion. The first criterion is directly linked to power performance of the engine, while the latter has been shown to control the burn rate in IC engines. Enhanced burn rates are favorable to engine efficiency and partial load performance. CFD based numerical simulations have recently made it possible to study the development of such engine flows in great details. However, they offer little guidance for modifying the ports and chamber geometry controlling the flow to meet the desired performance. This paper presents a methodology which combines 3D, steady state CFD techniques with robust numerical optimization tools to design, rather than just evaluate the performance, of IC engine ports and chambers. La forte concurrence et les réglementations dans l'industrie automobile entraînent aujourd'hui une exigence sans précédent de performance, de rendement et d'émissions pour les moteurs à combustion interne. Le succès ou l'échec de la conception d'un nouveau moteur satisfaisant à ces propriétés, souvent contradictoires, est dicté, dans un premier temps, par l'obtention d'une restriction minimale des débits d'admission et d'échappement, ensuite, par la nécessité de générer des écoulements forts de grande amplitude. Le premier critère est directement lié à la performance du moteur, tandis que le second est reconnu comme contrôlant la combustion. Des dégagements de chaleur accélérés améliorent le rendement et les performances à faible charge. La simulation 3D rend possible depuis peu d

  18. Fission product determination in irradiated fuel processing waste (electrophoresis); Dosage des produits de fission dans les effluents de traitement des combustibles irradies (electrophorese)

    Energy Technology Data Exchange (ETDEWEB)

    Auchapt, J.M.; Tret, J. [Commissariat a l' Energie Atomique, Centre de Marcoule, 30 - Bagnols-sur-Ceze (France). Centre de Production de Plutonium de Marcoule. Services d' Extraction du Plutonium

    1966-07-01

    This dosage method concerns fission products present in the waste produced from the processing of cooled irradiated fuels. - Sr, Cs, Ce, Y, Ru by quantitative analysis; - Zr, Nb by qualitative analysis. It includes electrophoresis on paper strips one meter long which is then analysed between two window-less Geiger counters. For an activity of 10{sup -2} {mu}Ci of any cation in a 10 {mu}l spot, the standard error {sigma} if 3 to 4 per cent. complete analysis lasts about 5 hours. (authors) [French] Cette methode de dosage concerne les produits de fission presents dans les effluents de traitement des combustibles irradies refroidis: - Sr, Cs, Ce, Y, Ru en analyse quantitative; - Zr, Nb en analyse qualitative. Elle comporte une electrophorese sur bande de papier de un metre de longueur suivie d'un depouillement entre deux compteurs Geiger sans fenetre. Pour une activite de 10{sup -2} {mu}Ci d'un cation quelconque dans une tache de 10 {mu}l l'erreur standard {sigma} est de 3 a 4 pour cent. L'analyse complete demande environ 5 heures. (auteurs)

  19. Evolution des modèles mathématiques directs appliqués aux moteurs à combustion interne Evolution of Direct Mathematical Models Applied to Internal-Combustion Engines

    Directory of Open Access Journals (Sweden)

    Rumiano N.

    2006-11-01

    Full Text Available Cet article rend compte de l'évolution présente et future des modèles mathématiques directs de simulation dans les moteurs. Ceux-ci sont basés sur la résolution des équations de Navier-Stokes, et deviennent peu à peu une nécessité surtout en ce qui concerne la combustion hétérogène. Après un aperçu sur l'état actuel des algorithmes de calcul et des sous-modèles physiques utilisés, on présente une revue des principaux codes de calcul appliqués au moteur, avec quelques-uns de leurs résultats. Après avoir évoqué les obstacles rencontrés lors de leur mise en oeuvre, on aborde l'évolution prévisible lors des prochaines années, tant pour les techniques de calcul que pour les codes eux-mêmes. This article describes the present and future evolution of direct mathematical models used for engine simulation. These models are based on the solving of Navier-Stokes equations and are gradually becoming an absolute necessity, especially with regard to heterogeneous combustion. Alter briefly describing the present state of the computing algorithms and physical submodels used, the leading computing codes applied to engines are reviewed, with some of their results. Then the stumbling blocks encountered during the implementation of these codes are described, followed by the foresable evolution in the next few years, for both computing techniques and the codes themselves.

  20. Optimization of Gas Turbine Cogeneration Systemfor Various Heat Exchanger Configurations Optimisation des systèmes de turbine à combustion en cogénération pour différentes configurations des échangeurs de chaleur

    Directory of Open Access Journals (Sweden)

    Costea M.

    2011-11-01

    Full Text Available The present paper investigates and compares the performance of three configurations of Gas Turbine systems allowing cogeneration of heat and electricity, on the basis of an irreversible regenerative Brayton-Joule cycle. The proposed model is developed for two different cycle constraints, namely, an imposed heat transfer rate released by the fuel combustion, or an imposed maximum cycle temperature. The model also includes the irreversibility due to the friction in the compressor and turbine, and due to the heat losses in the combustion chamber and heat exchangers. Energy efficiency for the system without and with cogeneration, and the exergetic efficiency are used in order to emphasize the cogeneration advantages, but also to help the designer to choose the best configuration of the Gas Turbine system that suits to his needs. Experimental data from a real operating microturbine were used to validate the model. The power output and the energy and exergetic efficiencies are optimized with respect to a set of operating parameters. The optimum values of the Gas Turbine engine parameters corresponding to maximum power output and respectively to maximum thermodynamic efficiency are discussed. The results show same optimal values of the compression ratio corresponding to almost all maximum performances for an imposed heat transfer rate released by the fuel combustion, excepting the maximum exergetic efficiency that requires higher optimal values of the compression ratio than the maximum exergy rate one. A performance comparison of the three configurations is done and future perspectives of the work are proposed. Cet article explore et compare les performances des trois configurations de systèmes de turbine à combustion permettant la production combinée de chaleur et d’électricité, sur la base du cycle irréversible régénératif de Brayton-Joule. Le modèle proposé est développé pour deux contraintes différentes sur le cycle, notamment le

  1. Energetic study of combustion instabilities and genetic optimisation of chemical kinetics; Etude energetique des instabilites thermo-acoustiques et optimisation genetique des cinetiques reduites

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Ch.E.

    2005-12-15

    Gas turbine burners are now widely operated in lean premixed combustion mode. This technology has been introduced in order to limit pollutants emissions (especially the NO{sub x}), and thus comply with environment norms. Nevertheless, the use of lean premixed combustion decreases the stability margin of the flames. The flames are then more prone to be disturbed by flow disturbances. Combustion instabilities are then a major problem of concern for modern gas turbine conception. Some active control systems have been used to ensure stability of gas turbines retro-fitted to lean premixed combustion. The current generation of gas turbines aims to get rid of these control devices getting stability by a proper design. To do so, precise and adapted numerical tools are needed even it is impossible at the moment to guarantee the absolute stability of a combustion chamber at the design stage. Simulation tools for unsteady combustion are now able to compute the whole combustion chamber. Its intrinsic precision, allows the Large Eddy Simulation (LES) to take into account numerous phenomena involved in combustion instabilities. Chemical modelling is an important element for the precision of reactive LES. This study includes the description of an optimisation tools for the reduced chemical kinetics. The capacity of the LES to capture combustion instabilities in gas turbine chamber is also demonstrated. The acoustic energy analysis points out that the boundary impedances of the combustion systems are of prime importance for their stability. (author)

  2. Combustion and environment. The answers from the energy and equipment suppliers; Combustion et environnement. Les reponses des fournisseurs d`energie et d`equipements

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    This paper is a reprint of an article published in `Energie Plus` magazine which questions the capability of commercial fuels and combustion equipments (central heating plants, burners, turbines and engines) available today of respecting the limit values of pollutant emissions (SO{sub x}, NO{sub x}, CO, dusts) of forthcoming regulations. An analysis of the situation is given separately for the fuels (natural gas, coal, heavy fuels) with a stress on the competition aspects, and for the combustion systems (turbines, diesel and gas engines, central heating plants). (J.S.)

  3. Air pollution emission reduction techniques in combustion plants; Technique de reduction des emissions de polluants atmospheriques dans les installations de combustion

    Energy Technology Data Exchange (ETDEWEB)

    Bouscaren, R. [CITEPA, Centre Interprofessionnel Technique d`Etudes de la Pollution Atmospherique, 75 - Paris (France)

    1996-12-31

    Separating techniques offer a large choice between various procedures for air pollution reduction in combustion plants: mechanical, electrical, filtering, hydraulic, chemical, physical, catalytic, thermal and biological processes. Many environment-friendly equipment use such separating techniques, particularly for dust cleaning and fume desulfurizing and more recently for the abatement of volatile organic pollutants or dioxins and furans. These processes are briefly described

  4. Influence de la nature des fuels lourds sur la qualité de leur combustion Influence of Heavy Fuel Oil Composition on Particulate Emissions

    Directory of Open Access Journals (Sweden)

    Feugier A.

    2006-11-01

    Full Text Available A partir d'études de combustion de fuels lourds numéro 2 effectuées dans une chaudière de 1 MW et dans un foyer de 0,1 MW, on conclut que le résidu de Carbone Conradson (CCR des fuels est un bon indicateur de leur combustibilité, mais qu'il n'est pas suffisant dans tous les cas, c'est-à-dire que pour un même CCR, on peut mesurer des valeurs différentes en indice pondéral. Plusieurs interpréta. tions possibles ont été proposées et vérifiées : a Le résidu de Carbone Conradson, résultat d'une pyrolyse lente, est une procédure qui n'est pas suffisamment représentative des conditions réelles. Or, en soumettant un certain nombre de fuels à une pyrolyse flash (technique de la grille chauffée, on observe une bonne corrélation entre la quantité de résidu résultant et le CCR. Donc, ce dernier reste un bon indicateur de combustibilité. b Pour les fuels ex résidu atmosphérique, ex résidu sous-vide et ex désasphaltage, on détermine de satisfaisantes corrélations entre le CCR et certaines caractéristiques physico-chimiques de la fraction lourde des fuels (point de coupe choisi 450°C : polyaromaticité (mesurée par RMN du Carbone 13, C/H, masse moléculaire. Cependant, les fuels de visco-réduction satisfont à d'autres corrélations, de même que les résidus de vapocraquage. Donc, pour ces classes de fuels, on peut prévoir des anomalies entre indice pondéral et CCR, ce qui est observé dans certains équipements. c On observe que pour une même valeur de CCR, la proportion relative entre fractions légères et fractions lourdes des fuels peut parfois varier très sensiblement avec pour conséquence des modifications dans les cartes de richesse et de température des flammes résultantes, et donc des variations dans les émissions particulaires. L'importance de telles variations dépendra des types de brûleurs et de chambres de combustion dans lesquelles la flamme se développera. On the basis of combustion runs of

  5. Modélisation de la combustion de fuels lourds prenant en compte la dispersion des asphaltènes Modeling Heavy Fuel-Oil Combustion (While Considering Or Including Asphaltene Dispersion

    Directory of Open Access Journals (Sweden)

    Audibert F.

    2006-11-01

    Full Text Available Divers modèles, ayant pour but de prédire le taux d'imbrûlés solides lors de la combustion du fuel lourd, ont été mis au point dans le passé. Les paramètres entrant en ligne de compte sont le plus souvent les teneurs en résidus lourds hydrocarbonés (asphaltènes précipités au pentane ou à l'heptane et carbone Conradson et en métaux : c'est le cas des modèles Exxon et Shell développés respectivement en 1979 et 1981. D'autres modèles tiennent compte, en plus de la composition du fuel, de son mode d'atomisation, de son mode de diffusion dans le foyer et de la cinétique de combustion : on peut citer les travaux du Laboratoire Energie du MIT publiés en 1986. Néanmoins, ces facteurs ne sont pas les seuls à intervenir : l'expérience a montré que l'état de dispersion des asphaltènes peut jouer également un grand rôle, notamment dans le cas d'installations de combustion à injection mécanique, pour lesquelles la dispersion des gouttelettes n'est pas aussi fine que pour des installations munies d'une injection assistée par la vapeur. Cette influence de la dispersion des asphaltènes sur la combustion a été mise en évidence dans le passé par l'utilisation d'additifs dispersants et également par la combustion de fuels lourds constitués par dilution d'asphaltes précipités au pentane avec un gas-oil de cracking catalytique de raffinerie (LCO. Ce sont ces fuels que l'on a considérés dans la présente étude. L'effet de ce facteur dispersion n'a pas été quantifié jusqu'alors, la difficulté étant de définir une grandeur mesurable représentant la répartition des agglomérats d'asphaltènes. Dans cette étude, on a essayé en un premier temps de faire une approche fractale de la répartition des asphaltènes à partir de clichés (préparés par la société Total, cette méthode ayant déjà été utilisée avec succès pour décrire des structures d'aspects comparables. Malheureusement, on s'est heurté à des

  6. Properties of low content uranium-molybdenum alloys which may be used as nuclear fuels; Proprietes des alliages uranium-molybdene de faibles teneurs utilisables comme materiaux combustibles

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, J.; Decours, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    sont presentees les caracteristiques metallurgiques des alliages uranium-molybdene de teneurs comprises entre 0,5 et 3 pour cent en poids de molybdene. Certains de ces alliages etant utilises dans les piles de puissance EdF, nous indiquons brievement les conditions de fonctionnement demandees aux materiaux combustibles: temperature maximum, gradient de temperature et pression externe. Dans une premiere partie sont etudiees les proprietes structurales des alliages en correlation avec les cinetiques des transformations de phases, nous decrivons les incidences de differents facteurs physico-metallurgiques sur la morphologie et sur la structure cristalline des materiaux: - conditions de solidification et heredite de la structure {gamma}, - vitesse de refroidissement au passage des points de transformation - suppression ou non de la transformation intermediaire {gamma} {yields} {beta} Dans une seconde partie, nous indiquons comment la connaissance des processus des transformations de phase a permis de definir les conditions d'elaboration optimales de ces materiaux sous forme de tubes de combustibles destines aux reacteurs EdF: conditions de coulee traitement de refroidissement controle, soudabilite. Dans une troisieme partie, nous etudions la stabilite thermique au cours de paliers de longue duree a haute temperature et de cycles, dans les deux domaines du diagramme d'equilibre {alpha} + {gamma}, {beta} + {gamma}; les influences de la morphologie (en particulier des deux types de pseudo-grains {alpha} observes) et de la vitesse de refroidissement lors du passage des points de transformation sont discutees. Dans une quatrieme partie, les proprietes mecaniques sont discutees resistance a la traction, resistance au fluage, resilience. Ces proprietes peuvent etre egalement influencees par l'heredite de la structure {gamma} et par la vitesse de refroidissement subie par l'alliage. En conclusion, nous developpons les raisons qui ont motive le choix de certains

  7. Natural gas combustion and indoor air quality in domestic premises; Combustion du gaz naturel et qualite de l'air a l'interieur des habitations

    Energy Technology Data Exchange (ETDEWEB)

    Occhio, L.; Riva, A. [Snam, (Italy); Canci, F.; Scevarolli, V. [Italgas, Torino (Italy)

    2000-07-01

    Indoor air quality depends on many factors; combustion appliances are one of the sources of emissions inside dwellings. Their installation is regulated by UNI-CIG standards which also establish the ventilation and aeration requirements needed to guarantee the safety and healthiness of the environment. In order to critically evaluate the effect on indoor air quality of using gas appliances under different operational regimes and in different types of building, Snam and Italgas have developed a research project in co-operation with Enitecnologie and Turin Polytechnic, even to provide theoretical and experimental support for standardisation activities. The results of the presented research include experimental measurements made in real buildings, mathematical modelling and analysis of Italian and international literature. The results show that use of combustion appliances has little influence on indoor air quality and does not affect people's health. (authors)

  8. Experimental and numerical study of the active control of jets inside combustion chambers; Etude experimentale et numerique du controle actif de jets dans des chambres de combustion

    Energy Technology Data Exchange (ETDEWEB)

    Faivre, V.

    2003-12-15

    Combustion instabilities occur when the flame heat release couples with the acoustic waves propagating in the combustion chamber. This phenomenon can lead to strong vibrations and noise but also, sometimes, to the complete combustion device failure. That is the reason why so many studies focus on the control of those instabilities. The method chosen in this study consists in an active control device (or set of actuators) having a strong effect on the mixing of the burner exhaust flow with the ambient fluid. The model configuration studied consists in a non reactive jet of air controlled by four small tangential secondary jets. Experiments have been carried out to optimize the control device geometry. The configuration identified as the most efficient, in terms of mixing enhancement, has been simulated through Large Eddy Simulations (LES). The objective of the numerical part of the present work is double. First, the numerical simulations provide a better understanding of the phenomena occurring when the control is on. Then, it is shown that LES can be considered as a tool to predict the effects of a control device on a flow. (author)

  9. A Contribution to Turbulent Combustion: Premixed Flames and Material Surfaces Une contribution à la combustion turbulente : flammes prémélangées et surfaces des matériaux

    Directory of Open Access Journals (Sweden)

    Nicolleau F.

    2006-11-01

    from each other. The turbulent diffusion process is very active to create new burning zones. This diffusion process is closely related to both the intensity and the length scale of the turbulent field. That explains the dominant role of turbulence and the adaptation of the burning rate to the rotation speed in combustion engines. Additional information useful for the reader is reported in Appendices I and II. Le comportement des flammes de prémélange a été examiné par de nombreux auteurs. En fait, le problème de la combustion en milieu turbulent repose pour beaucoup sur des comparaisons d'échelles. Dans le présent article, une première étude porte sur l'évolution d'une surface matérielle (qui peut être assimilée sous certaines conditions à une surface de flamme. On utilise successivement une démarche analytique et une démarche numérique. On constate alors la rapidité d'extension de la surface et le rôle prépondérant des petites échelles ce que confirme l'étude analytique. Les risques d'extinction sont prédits en général par comparaison d'échelles. D'une simulation directe conduite sur un cas spécifique, Poinsot confirme l'idée que ce ne sont pas les structures ayant les échelles caractéristiques de la flamme qui sont les plus redoutables, mais des structures de taille quelque peu plus grande. Dans un précédent article, le rôle cumulé des gradients locaux avait été signalé. Nous donnons à ce concept une forme quantitative en utilisant le ß modèle lequel définit un taux d'occupation de l'espace en fonction du rang (et donc de la dimension de structures. Un calcul de gradient cumulé redonne la prédiction de Poinsot. Enfin, le même ß modèle est utilisé pour définir une nouvelle zone dans la région de combustion distribuée. Des balles fluides brûlent isolément tandis qu'un processus de diffusion lié très étroitement au champ turbulent et à son intensité crée d'autres points d'allumage. Le mécanisme explique l

  10. Combustion gas cleaning in the ceramic tile industry: technical guide; Nettoyage des fumees de combustion dans l'industrie ceramique: guide technique

    Energy Technology Data Exchange (ETDEWEB)

    Lezaun, F.J. [ENAGAS-Grupo Gas Natural (Spain); Mallol, G.; Monfort, E. [instituto de Tecnologia Ceramica, ITC (Spain); Busani, G. [Agenzia Regionale per la Prevenzione e l' Amiente, ARPA (Spain)

    2000-07-01

    This document presents a summary of a technical guide drawn up on combustion gas cleaning systems in ceramic frit and tile production. The guide describes the method to be followed for selecting the best possible solutions for reducing pollutant concentrations in different emission sources, in accordance with current regulatory requirements and the CET recommendation. There are three sources of combustion gas air emissions that need to be cleaned in ceramic tile and frit production and they are usually related to the following process stages: slip spray drying, tile firing and frit melting. The different nature of the emissions means that different substances will need to be cleaned in each emission. Thus, in spray drying and frit melting, the only species to be cleaned are suspended particles, while in tile firing, it is also necessary to reduce the fluorine concentration. The systems analysed in this guide are mainly wet cleaning systems, bag filters and electrostatic precipitators. In the study, the efficiency of these cleaning systems is compared at each emission source from a technical and economic point of view, and concrete solutions are put forward in each case, together with a list of suppliers of the technologies involved. (authors)

  11. Pollution active control: a strategy for a clean and efficient combustion; Le controle actif des polluants: une strategie pour une combustion propre et efficace

    Energy Technology Data Exchange (ETDEWEB)

    Lacas, F. [CNRS Ecole Centrale de Paris, 75 (France). Laboratoire E.M2.C

    1996-12-31

    The active control NOx reduction concept has been applied on two burners (20 kW and 840 kW), using a rotary valve enabling an excitation in the 100 to 1000 Hz band, that can be mounted on existing appliances such as domestic or industrial boilers. NOx level reduction may reach 15 pc for the 20 kW burner, 25 pc for the 840 kW burner with domestic fuel oil and 35 pc for the 840 kW burner using pyridine doped domestic fuel oil. Mechanisms are detailed through flow visualization, and consist mainly in an annular vortex inducing a fuel/air pre-mixing favourable to a large decrease in NOx generation level and establishing a staged process such as in re-burning processes. The pulsed combustion process may be also combined to other pollution control systems

  12. Construction and validation of detailed kinetic models for the combustion of gasoline surrogates; Construction et validation de modeles cinetiques detailles pour la combustion de melanges modeles des essences

    Energy Technology Data Exchange (ETDEWEB)

    Touchard, S.

    2005-10-15

    The irreversible reduction of oil resources, the CO{sub 2} emission control and the application of increasingly strict standards of pollutants emission lead the worldwide researchers to work to reduce the pollutants formation and to improve the engine yields, especially by using homogenous charge combustion of lean mixtures. The numerical simulation of fuel blends oxidation is an essential tool to study the influence of fuel formulation and motor conditions on auto-ignition and on pollutants emissions. The automatic generation helps to obtain detailed kinetic models, especially at low temperature, where the number of reactions quickly exceeds thousand. The main purpose of this study is the generation and the validation of detailed kinetic models for the oxidation of gasoline blends using the EXGAS software. This work has implied an improvement of computation rules for thermodynamic and kinetic data, those were validated by numerical simulation using CHEMKIN II softwares. A large part of this work has concerned the understanding of the low temperature oxidation chemistry of the C5 and larger alkenes. Low and high temperature mechanisms were proposed and validated for 1 pentene, 1-hexene, the binary mixtures containing 1 hexene/iso octane, 1 hexene/toluene, iso octane/toluene and the ternary mixture of 1 hexene/toluene/iso octane. Simulations were also done for propene, 1-butene and iso-octane with former models including the modifications proposed in this PhD work. If the generated models allowed us to simulate with a good agreement the auto-ignition delays of the studied molecules and blends, some uncertainties still remains for some reaction paths leading to the formation of cyclic products in the case of alkenes oxidation at low temperature. It would be also interesting to carry on this work for combustion models of gasoline blends at low temperature. (author)

  13. Une installation expérimentale pour l'étude du traitement par combustion des fumées industrielles An Experimental Plant for Processing Industrial Fumes by Combustion

    Directory of Open Access Journals (Sweden)

    Morillon R.

    2006-11-01

    Full Text Available Le rejet à l'atmosphère d'effluents gazeux d'origine industrielle entraîne un accroissement sensible de la pollution atmosphérique ; en outre, il s'accompagne souvent d'une perte d'énergie lorsque l'élément polluant est un hydrocarbure. Dans ce cas, l'utilisation du gaz naturel pour le traitement par combustion des fumées industrielles apporte une solution élégante et souvent peu coûteuse grâce à la récupération d'énergie qu'il est possible de faire. La première partie de l'article rappelle les aspects théoriques de ce traitement ; en particulier, l'influence des divers éléments sur son efficacité y est discutée (composition de l'atmosphère polluée, température, temps de séjour, etc.. II apparaît ainsi que diverses conditions doivent être remplies simultanément pour obtenir une efficacité satisfaisante. Afin de disposer d'éléments d'ingénierie permettant de construire les unités de traitement les plus efficaces et les plus sûres possible, au coût le plus bas possible, la Direction des études et techniques nouvelles du Gaz de France a réalisé une installation expérimentale qui est présentée dans la deuxième partie de l'article. Enfin, quelques examples d'utilisation de cette installation expérimentale, qui constitue un nouvel outil de travail mis à la disposition des utisitateurs et des constructeurs, sont décrits dans la troisième partie de l'article. The discharge into the atmosphere of industrial waste gases causes substantially increased air pollution. Moreover, it is often accompanied by loss of energy when the polluting element is a hydrocarbon. In such cases, the use of natural gas for processing industrial fumes by combustion provides an elegant solution, which moy often prove economical too becouse of the recovery of energy it makes possible. The first part of this article reviews the theoretical aspects of such processing. The way in which its effectiveness is affected by various parameters

  14. Effect of Ash on Oxygen Carriers for the Application of Chemical Looping Combustion to a High Carbon Char Effet des cendres sur l’activité des porteurs d’oxygène dans la combustion du charbon en boucle chimique

    Directory of Open Access Journals (Sweden)

    Rubel A.

    2011-02-01

    activity of the OCs and both OCs performed well. The results were promising for the application of CLC directly to solid fuels. L’application de la combustion en boucle chimique (CLC aux combustibles solides est actuellement étudiée à l’Université du Kentucky, au Centre de Recherche de l’Energie Appliquée (CAER dans le but de développer un procédé de gazéification/combustion en boucle chimique pressurisé (PCLC/G afin de générer de l’électricité à partir de charbon. Un des principaux aspects de la combustion en boucle chimique de combustibles solides est la compréhension de l’effet des cendres sur la réactivité des porteurs d’oxygène (OCs. L’effet des cendres sur la capacité de transfert d’oxygène et sur l’aptitude à oxyder le charbon est étudié avec deux porteurs d’oxygène à base d’oxydes de fer. Les cendres utilisées sont des cendres volantes provenant d’une centrale thermique au charbon. Les expériences sont réalisées dans un système composé d’une thermo-balance couplée à un spectrographe de masse (TGMS dans lequel on utilise d’abord 500 mg d’un mélange de cendres/porteurs d’oxygène à différentes concentrations de cendres allant jusqu’à 75 %. Le gaz réducteur est composé de 10 % de H2, 15 % de CO, 20 % de CO2 et de 55 % de Ar; et le gaz oxydant est composé de 20 % de O2 dans Ar. Les réactions d’oxydation/réduction sont quasi totales. D’après ces expériences, les cendres ont une activité propre de porteur d’oxygène, liée à la présence de fer dans les cendres, confirmée par les analyses DRX. Cela génère une augmentation du gain ou de la perte de masse du mélange pendant l’oxydation/réduction. Les vitesses d’oxydation/réduction augmentent avec la concentration des cendres à cause de l’augmentation de la porosité du mélange de porteurs d’oxygène avec les cendres, ce qui permet un meilleur accès des gaz réactifs sur les sites actifs des porteurs d’oxygène. Dans un

  15. Radiative transfer modelling in combusting systems using discrete ordinates method on three-dimensional unstructured grids; Modelisation des transferts radiatifs en combustion par methode aux ordonnees discretes sur des maillages non structures tridimensionnels

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, D.

    2004-04-01

    The prediction of pollutant species such as soots and NO{sub x} emissions and lifetime of the walls in a combustion chamber is strongly dependant on heat transfer by radiation at high temperatures. This work deals with the development of a code based on the Discrete Ordinates Method (DOM) aiming at providing radiative source terms and wall fluxes with a good compromise between cpu time and accuracy. Radiative heat transfers are calculated using the unstructured grids defined by the Computational Fluid Dynamics (CFD) codes. The spectral properties of the combustion gases are taken into account by a statistical narrow bands correlated-k model (SNB-ck). Various types of angular quadrature are tested and three different spatial differencing schemes were integrated and compared. The validation tests show the limit at strong optical thicknesses of the finite volume approximation used the Discrete Ordinates Method. The first calculations performed on LES solutions are presented, it provides instantaneous radiative source terms and wall heat fluxes. Those results represent a first step towards radiation/combustion coupling. (author)

  16. 3-D modeling of parietal liquid films in internal combustion engines; Modelisation tridimensionnelle des films liquides parietaux dans les moteurs a combustion interne

    Energy Technology Data Exchange (ETDEWEB)

    Foucart, H.

    1998-12-11

    To simulate the air-fuel mixing in the intake ports and cylinder of an internal combustion engines, a wall fuel liquid film model has been developed for integration in 3D CFD codes. Phenomena taken into account include wall film formation by an impinging spray without splashing effect, film transport such as governed by mass and momentum equations with hot wall effects, and evaporation considering energy equation with an analytical mass transfer formulation developed here. A continuous-fluid method is used to describe the wall film over a three dimensional complex surface. The basic approximation is that of a laminar incompressible boundary layer; the liquid film equations are written in an integral form and solved by a first-order ALE finite volume scheme; the equation system is closed without coefficient fitting requirements. The model has been implemented in a Multi-Block version of KIVA-II (KMB) and tested against problems having theoretical solutions. Then in a first step, it has been compared to the measurements obtained in a cylindrical pipe reproducing the main characteristics of SI engine intake pipe flow and in a second step, it has been compared to the Xiong experiment concerning the film evaporation on a hot wall. The film behaviour is satisfactory reproduced by the computations for a set of operating conditions. Finally, engine calculations were conducted showing the importance of including a liquid film model for the simulations. (author) 54 refs.

  17. Modélisation 0D de la combustion des carburants alternatifs dans les moteurs à allumage commandé

    OpenAIRE

    Bougrine , Sabre

    2012-01-01

    A promising way to reduce green house gases emissions of spark ignition (SI) engines is to burn alternative fuels like bio-mass-derived products, hydrogen or compressed natural gas. However, their use strongly impacts combustion processes in terms of burning velocity and emissions. Specific engine architectures as well as dedicated control strategies should then be optimized to take advantage of these fuels. Such developments are today increasingly performed using complete engine simulators r...

  18. Effect of Ash on Oxygen Carriers for the Application of Chemical Looping Combustion to a High Carbon Char; Effet des cendres sur l'activite des porteurs d'oxygene dans la combustion du charbon en boucle chimique

    Energy Technology Data Exchange (ETDEWEB)

    Rubel, A.; Zhang, Y.; Liu, K.; Neathery, J. [University of Kentucky, Center for Applied Energy Research, 2540 Research Park Drive, Lexington, KY (United States)

    2011-03-15

    The application of Chemical Looping Combustion (CLC) to solid fuels is being investigated at the University of Kentucky, Center for Applied Energy Research (CAER) with the aim of the development of a Pressurized Chemical Looping Combustion/Gasification (PCLC/G) process for the generation of electricity from coal. One important aspect of the CLC of solid fuel is the understanding of the effect of ash on the reactivity of Oxygen Carriers (OCs). The effect of ash on the redox capabilities of two different iron oxide OCs and on their ability to oxidize coal char was studied. To determine the effect of ash on the reactivity and recycle of the OCs through multiple redox cycles, fly ash from a coal-fired power plant was used. These experiments were performed in a TGMS system using 500 mg of ash/OC mixtures containing different ash concentrations up to 75%. The reducing gas was composed of 10% H{sub 2}, 15% CO, 20% CO{sub 2}, and a balance of Ar and the oxidizing gas was 20% O{sub 2} in Ar. Oxidation/reductions were carried to near completion. The ash was found to contain OC activity related to inherent iron present in the ash confirmed by XRD. This resulted in increased weight gain/loss on oxidation/reduction. The rate of oxidation/reduction increased with ash concentration due to increased porosity of the OC/ash mixture and better access of the reactive gases to the OC target sites. The two OCs were then used to combust a beneficiated coal char in the TGMS with the only oxygen supplied by an iron oxide OC. The starting mixture was 10% char and 90% of one of two OCs studied. The spent material containing reduced OC and ash was re-oxidized and 10% more char was added for a second reduction of the OC and oxidation of the added char. This procedure was repeated for 5 cycles increasing the ash concentrations from 5 to 25% in the char/ash/OC mixture. Carbon removal was 92 to 97.8 and 97.3 to 99.7% for the two different iron oxide OCs tested. Ash was not detrimental to the

  19. Xonon combustion system, 2,5 p.p.m NOx for gas turbines; Le processus de combustion Xonon limite les emissions des turbines a gaz a 2,5 p.p.m

    Energy Technology Data Exchange (ETDEWEB)

    Solt, Ch. [Catalytica Energy Systems Inc., California (United States)

    2001-07-01

    A gas turbine operates by compressing incoming air, combining it with fuel, and combusting the mixture. The combustion process releases the fuel's energy, forming hot gases that power the turbine. In conventional combustion systems, a flame is used to combust the fuel. The temperature required to sustain a stable flame is significantly higher than the temperature at which the gas turbine is designed to operate. This excessive temperature causes the nitrogen and oxygen in the air to react, forming nitrogen oxides (NOx), a major contributor to air pollution. We have developed Xonon{sup TM} Cool Combustion, a catalytic technology that combusts fuel flamelessly. This process releases the same amount of energy as flame-based combustion systems but at a lower temperature. Importantly, this lower temperature is below the threshold at which NOx is formed. The Xonon combustion system is the only operating catalytic combustion system demonstrated to achieve near-zero emissions. The Xonon combustion system is a pollution prevention technology that has been proven to limit emissions of NOx to less than 2.5 parts per million (ppm) without compromising the performance of the gas turbine engine. (author)

  20. Simplified prediction of soot emissions in the exhaust of gas turbines operated at atmospheric pressure; Prediction simplifiee des emissions de suie a la sortie des chambres de combustion des turbines a gaz operees a la pression atmospherique

    Energy Technology Data Exchange (ETDEWEB)

    Tsogo, J. [College de la garde cotiere du Canada, Departement de genie maritime, Sydney (Canada); Kretschmer, D. [Universite Laval, Departement de genie mecanique, Quebec (Canada)

    2010-04-15

    In previous works [1, 2], a correlation for the prediction of soot in gas turbine exhaust has been presented. The development of the correlation is based on 300 of experimental data for a total of 19 fuels burned both at atmospheric and high pressure (0.1 to 0.9 MPa) and two scales (1/2 and 1/3) of a Laval type combustion chamber. With the wide range of fuels burned in the experiment giving a smoke number variation from 0 to 100, the accuracy of the correlation (Standard Deviation of 40%) is acceptable for most purposes Later on the correlation has been improved using data from the full scaled combustion chamber as shown in [3]. A detailed analysis of the correlation is undertaken within the present work for the case of the experiments at atmospheric pressure. The result is a simplification of the correlation presented in [3] without a major deterioration of the standard deviation. This result leads to a simplification of the previous proposed soot formation and oxidation model within gas turbine combustors (operated at atmospheric pressure) and limits the analysis of the phenomenon on essential functional parameters as well. Gas turbines are generally used in aircraft, ships, and in stationary production of electricity, heat and vapor. (author)

  1. Study of physico-chemical release of uranium and plutonium oxides during the combustion of polycarbonate and of ruthenium during the combustion of solvents used in the reprocessing of nuclear fuel; Etude de la mise en suspension physico-chimique des oxydes de plutonium et d'uranium lors de la combustion de polycarbonate et de ruthenium lors de la combustion des solvants de retraitement du combustible irradie

    Energy Technology Data Exchange (ETDEWEB)

    Bouilloux, L

    1998-07-01

    The level of consequences concerning a fire in a nuclear facility is in part estimated by the quantities and the physico-chemical forms of radioactive compounds that may be emitted out of the facility. It is therefore necessary to study the contaminant release from the fire. Because of the multiplicity of the scenarios, two research subjects were retained. The first one concerns the study of the uranium or plutonium oxides chemical release during the combustion of the polycarbonate glove box sides. The second one is about the physico chemical characterisation of the ruthenium release during the combustion of an organic solvent mixture (tributyl phosphate-dodecane) used for the nuclear fuel reprocessing. Concerning the two research subjects, the chemical release, i.e. means the generation of contaminant compounds gaseous in the fire, was modelled using thermodynamical simulations. Experiments were done in order to determine the ruthenium release factor during solvent combustion. A cone calorimeter was used for small scale experiments. These results were then validated by large scale tests under conditions close to the industrial process. Thermodynamical simulations, for the two scenarios studied. Furthermore, the experiments on solvent combustion allowed the determination of a suitable ruthenium release factor. Finally, the mechanism responsible of the ruthenium release has been found. (author)

  2. A Physics and Tabulated Chemistry Based Compression Ignition Combustion Model: from Chemistry Limited to Mixing Limited Combustion Modes Un modèle de combustion à allumage par compression basé sur la physique et la chimie tabulée : des modes de combustion contrôlés par la chimie jusqu’aux modes contrôlés par le mélange

    Directory of Open Access Journals (Sweden)

    Bordet N.

    2011-11-01

    experimental measurements carried out on a 2 liter Renault Diesel engine and good agreements are found. Ce papier présente une nouvelle approche 0D phénoménologique pour prédire le déroulement de la combustion dans les moteurs Diesel à injection directe pour toutes les conditions d’utilisation usuelles. Le but de ce travail est de développer une approche physique en vue d’améliorer la prédiction de la pression cylindre et du dégagement d’énergie, avec un nombre minimum d’essais nécessaires à la calibration. Les contributions principales de cette étude sont la modélisation de la phase de pré-mélange de la combustion et une extension du modèle pour les stratégies d’injections multiples. Dans ce modèle, le taux de dégagement d’énergie dû à la combustion pour la phase pré-mélangée est relié à un taux de réaction moyen du carburant. Ce taux de réaction moyen de carburant est évalué à l’aide d’une approche basée sur un taux de réaction local de carburant tabulé et la détermination d’une fonction de densité de probabilité (PDF de la fraction de mélange (Z. Cette PDF permet de prendre en compte la distribution de richesse existante dans la zone pré-mélangée. L’allure de cette PDF présumée est une β-fonction standardisée. Les fluctuations de la fraction de mélange sont décrites avec une équation de transport pour la variance de Z. La définition standard de la fraction de mélange, établie dans le cas de flammes de diffusion, est ici adaptée à une combustion pré-mélangée de type Diesel pour décrire l’inhomogénéité de la richesse dans le volume de contrôle. La chimie détaillée est décrite au travers de la tabulation du taux de réaction relatif à la flamme principale et du délai d’auto-inflammation relatif à la flamme froide, ces tabulations sont fonction de la variable d’avancement c, du taux de gaz brûlé ainsi que des grandeurs thermodynamiques telles que la température et la pression. Le

  3. Synthèse unifiée de commandes robustes pour la chaine d'air des moteurs à combustion interne

    OpenAIRE

    Deng, Chao

    2013-01-01

    Since the creation of internal combustion engines, research on gasoline and diesel engines were developed independently. To reduce the time and cost of developing an engine, a unified design approach would be interesting. In this context, control and development of internal combustion engines could also be unified. Obviously, this control must be stable, robust with respect to manufacturing disparities and operating points. This thesis then focuses on a unified approach for gasoline engines a...

  4. Multi-Dimensional Modeling of Combustion and Pollutants Formation of New Technology Light Duty Diesel Engines Modélisation multidimensionnelle de la combustion et de la formation des polluants dans les nouveaux moteurs diesel automobiles

    Directory of Open Access Journals (Sweden)

    Belardini P.

    2006-12-01

    Full Text Available In the present paper some results, obtained by the use of modern numerical CFD tools, are presented. In particular, starting from the experimental characterization of a common rail DI Diesel engine, the empirical constants of the different submodels were tuned to obtain satisfactory results in some key test conditions. The main constraints of numerical models, to obtain a right scaling of pollutants predictions in the different test cases are analyzed. The numerical analysis demonstrates that the numerical CFD tools, at their stage of development, can help the engine designers to define the more promising strategies to obtain tailpipe emission control of common rail Diesel DI engines. Dans cet article, nous présentons les résultats obtenus en utilisant des outils de simulation de la mécanique des fluides numérique (CFD. À partir de résultats expérimentaux issus de la caractérisation d'un moteur Diesel common rail, les constantes empiriques de divers modèles ont été ajustées afin d'obtenir des résultats satisfaisants pour des cas tests représentatifs. Les principales contraintes des modèles numériques pour obtenir une bonne précision dans les différents cas d'études sont ici analysées. Cette analyse numérique montre que la CFD permet déjà, au stade de développement atteint, d'aider les ingénieurs à définir les stratégies les plus prometteuses pour maîtriser les émissions à l'échappement des moteurs Diesel à injection common rail.

  5. 3d Simulation of Di Diesel Combustion and Pollutant Formation Using a Two-Component Reference Fuel Simulation 3D de la combustion et de la formation des polluants dans un moteur Diesel à injection directe en utilisant un carburant de référence à deux composants

    Directory of Open Access Journals (Sweden)

    Barths H.

    2006-12-01

    reference fuels. The contributions of the different reaction paths (thermal, prompt, nitrous, and reburn to the NO formation are shown. Finally, the importance of the mixing process for the prediction of soot emissions is discussed. En séparant calculs aérodynamiques et calculs chimiques, le modèle instationnaire de flamelet permet d'introduire des mécanismes chimiques complets qui comprennent plusieurs centaines de réactions. Ceci est indispensable pour décrire les différents processus qui ont lieu dans un moteur Diesel à injection directe (ID tels que l'auto-inflammation, la fin de la phase de prémélange partiel, la transition vers une combustion diffusive et la formation de polluants tels que les NOx et les suies. Il n'est pas nécessaire de simplifier les taux de réactions hautement non linéaires, d'autre part, la structure complète du processus de combustion est conservée. En utilisant le modèle de type Representative Interaction Flamelet (RIF, l'ensemble monodimensionnel instationnaire d'équations différentielles aux dérivées partielles est résolu en interaction avec le code CFD 3D. La solution ainsi obtenue est couplée avec les flux gazeux et le champ de mélange par l'intermédiaire de plusieurs paramètres dépendant du temps (l'enthalpie, la pression, le taux scalaire de dissipation. En retour, le modèle de flamelet fournit les concentrations moyennes des espèces chimiques, qui sont ensuite exploitées par le code CFD 3D pour calculer les champs de températures et les densités. La densité est nécessaire au code CFD 3D pour déterminer les flux turbulents et le champ de mélange. La formation des polluants est déterminée expérimentalement dans un moteur Diesel Volkswagen DI 1900. Le moteur est alimenté avec du gazole et deux carburants de référence. Un des carburants de référence est du n-décane pur. Le second est un carburant bicomposant formé de 70 % (du volume liquide de n-décane et de 30 % d'alpha-méthylnaphtalène (Idea

  6. Visualisation of Gasoline and Exhaust Gases Distribution in a 4-Valve Si Engine; Effects of Stratification on Combustion and Pollutants Visualisation de la répartition du carburant et des gaz brûlés dans un moteur à 4 soupapes à allumage commandé ; effet de la stratification sur la combustion et les polluants

    Directory of Open Access Journals (Sweden)

    Deschamps B.

    2006-12-01

    des dégagements d'énergie et des émissions de polluants très distincts. Le niveau de tumbleet l'emplacement de l'étincelle sont aussi modifiés. L'observation de la stratification telle qu'elle est réellement dans le moteur constitue un moyen pertinent pour expliquer ses performances. Les paramètres permettant d'optimiser les niveaux de NOx et d'HC peuvent en être déduits, de même que l'efficacité des stratégies de recirculation et d'injection du carburant. Les résultats des visualisations ont été confirmés par des mesures obtenues dans un moteur monocylindre muni d'une culasse conventionnelle avec la même géométrie de chambre de combustion.

  7. Proposal of a numerical modeling of reactive flows in combustion chambers of turbojet engines; Proposition d`une modelisation numerique des ecoulements reactifs dans les foyers de turboreacteurs

    Energy Technology Data Exchange (ETDEWEB)

    Ravet, F. [Rouen Univ., 76 - Mont-Saint-Aignan (France)]|[SNECMA, 77 - Moissy-Cramayel (France); Baudoin, Ch.; Schultz, J.L. [SNECMA, 77 - Moissy-Cramayel (France)

    1996-12-31

    Simplifying hypotheses are required when combustion and aerodynamic phenomena are considered simultaneously. In this paper, a turbulent combustion model is proposed, in which the combustion chemistry is reduced to a single reaction. In this way, only two variables are needed to describe the problem and combustion can be characterized by the consumption of one of the two reactive species. In a first step, the instantaneous consumption rate is obtained using the Lagrangian form of the mass fraction equation of the species under consideration, and by considering the equilibrium state only. This state is determined in order to preserve the consistency with results that should be obtained using a complete kinetics scheme. In a second step, the average rate is determined using the instantaneous consumption term and a probabilistic density function. This model was tested on various configurations and in particular on an experimental main chamber and on a reheating chamber. Results indicate that this model could be used to predict temperature levels inside these combustion chambers. Other applications, like the prediction of pollutant species emission can be considered. (J.S.) 12 refs.

  8. Experimental study of the aluminum droplet combustion under forced convection. Influence of the gaseous atmosphere; Etude experimentale de la combustion des gouttes d'aluminium en convection forcee. Influence de l'atmosphere gazeuse

    Energy Technology Data Exchange (ETDEWEB)

    Sarou-Kanian, V.

    2003-12-15

    Because of its high energetic power, the combustion of aluminum particles in solid propellant rocket motors improves the efficiency of heavy-lift launcher as Ariane 5. Aluminum particles burn in a gaseous atmosphere essentially composed of H{sub 2}O, CO{sub 2}, N{sub 2}, HCl, H{sub 2}, and CO, at high pressure (P=60-70 atm) and high temperature (T>3000 K). In the present work, we have been particularly interested in the influence of the gaseous atmosphere on the different burning processes both in the gas-phase and at the aluminum droplet surface. An experimental set-up was developed in order to describe precisely, thanks to several analysis techniques (high-speed camera, pyrometry, spectrometry, SEM, nuclear activation) the combustion of aerodynamically levitated millimetric aluminum droplets in gas mixtures with compositions close to the propellant ones (H{sub 2}O, CO{sub 2}, N{sub 2}). The main result is that each species plays a different role in the aluminum combustion. The water vapor has the biggest influence in the gas-phase process due to the production of hydrogen facilitating the heat and mass diffusion between the flame and the droplet. Nitrogen is essentially acting in surface reactions with the formation of aluminum nitride (AlN) and oxynitride (AlON) which may completely cover the droplet and stop the gas-phase combustion. Carbon dioxide has a double effect. On the one hand, CO{sub 2} burns in the flame, but it is less efficient than H{sub 2}O because the heat and mass transfer properties are poorer for CO than for H{sub 2}. On the other hand, a carbon dissolution phenomenon occurs in the aluminum droplet during burning which may reach saturation (20-25% molar) and involves a carbon rejection at the surface leading to the end of the gas-phase combustion. (author)

  9. Techniques de combustion Combustin Techniques

    Directory of Open Access Journals (Sweden)

    Perthuis E.

    2006-11-01

    Full Text Available L'efficacité d'un processus de chauffage par flamme est étroitement liée à la maîtrise des techniques de combustion. Le brûleur, organe essentiel de l'équipement de chauffe, doit d'une part assurer une combustion complète pour utiliser au mieux l'énergie potentielle du combustible et, d'autre part, provoquer dans le foyer les conditions aérodynamiques les plus propices oux transferts de chaleur. En s'appuyant sur les études expérimentales effectuées à la Fondation de Recherches Internationales sur les Flammes (FRIF, au Groupe d'Étude des Flammes de Gaz Naturel (GEFGN et à l'Institut Français du Pétrole (IFP et sur des réalisations industrielles, on présente les propriétés essentielles des flammes de diffusion aux combustibles liquides et gazeux obtenues avec ou sans mise en rotation des fluides, et leurs répercussions sur les transferts thermiques. La recherche des températures de combustion élevées conduit à envisager la marche à excès d'air réduit, le réchauffage de l'air ou son enrichissement à l'oxygène. Par quelques exemples, on évoque l'influence de ces paramètres d'exploitation sur l'économie possible en combustible. The efficiency of a flame heating process is closely linked ta the mastery of, combustion techniques. The burner, an essential element in any heating equipment, must provide complete combustion sa as to make optimum use of the potential energy in the fuel while, at the same time, creating the most suitable conditions for heat transfers in the combustion chamber. On the basis of experimental research performed by FRIF, GEFGN and IFP and of industrial achievements, this article describesthe essential properties of diffusion flames fed by liquid and gaseous fuels and produced with or without fluid swirling, and the effects of such flames on heat transfers. The search for high combustion temperatures means that consideration must be given to operating with reduced excess air, heating the air or

  10. Dynamique de combustion des végétaux et analyse des fumées émises, effets de l’échelle et du système

    OpenAIRE

    Romagnoli, Elodie

    2014-01-01

    Wildfires are characterized by a lot of scales of time and space. A multi-physics and multi-scale approach is required to consider the complexity of these phenomena. This thesis is an experimental contribution to the study of the scale effects and the effects of the system on the combustion dynamics of forest fuels and smoke emission. The aim of this work was to determine which experimental protocols and specifically which scales can be used to characterize the combustion of vegetal fuels in ...

  11. Burners. The decrease of nitrogen oxides in combustion process: the 2 nd generation GR LONOxFLAM burner; Les bruleurs, la reduction des oxydes d`azote dans la combustion: bruleur GR LONOxFLAM de 2. generation

    Energy Technology Data Exchange (ETDEWEB)

    Gauthier, J.C. [EGCI Pillard, 13 - Marseille (France)

    1997-12-31

    The Pillard company has developed, in cooperation with GDF (the French national gas utility), the GR-LONOxFLAM burner concept for reducing NOx emission levels and solid combustion products. The concept consists, for gaseous fuels, in the combination of an internal recirculation and a gas staging process; for liquid fuels, a separated flame process and air staging are combined. These concepts allow for an important reduction in NOx and non-burned residues, even with standard-size burners

  12. Formation and destruction mechanisms of nitrogen oxides during coal combustion in circulating fluidized beds; Mecanismes de formation et de destruction des oxydes d`azote lors de la combustion du charbon en lit fluidise circulant

    Energy Technology Data Exchange (ETDEWEB)

    Borrel, G.; Lecuyer, I. [Universite du Haut-Rhin, 68 - Mulhouse (France)

    1997-01-01

    Formation and reduction of nitrogen oxides (NO and N{sub 2}O) during coal combustion in a circulating fluidized bed (CFBC) are very complicated and yet badly known. The aim of the present study was to better characterize these phenomena on a small-sized experimental unit (reactor diameter: 5 cm), with the possibility to re-inject the solids in the bottom of the furnace, as in a real industrial unit. This should allow then to develop a numerical set of chemical reactions involving the nitrogen oxides. The experimental results showed that coal ash plays a great role in reducing nitrogen oxides, the determining parameter being the quantity of unburnt carbon remaining in the ash. The study then detailed the interaction between nitrogen oxides and de-volatilized (char) according to the temperature, NO{sub x} concentration and the mass of solid. In the absence of oxygen small quantities of char can very significantly reduce NO as well as N{sub 2}O. It was possible to establish destruction kinetics on these particles, and orders of reaction could be determined versus the NO{sub x} concentration and the char particle mass (heterogeneous phase chemical reactions). Then, the coal pyrolysis study enabled to identify the products released during coal devolatilization and thermogravimetric analyses displayed several successive weight losses due CO, CO{sub 2} and CH{sub 4} releases, during a linear temperature increase. Lastly coal combustion was studied in the small pilot with variable experimental conditions. Using the previous experimental was studied in the small pilot with variable experimental conditions. Using the previous experimental results, a model was developed to calculate NO{sub x} concentrations during the coal combustion and validated. The NO and N{sub 2}O contents calculated are thoroughly correlated with the experimental data whatever the injection carbon/oxygen ratio is. (author) 96 refs.

  13. The combustion system of the MAN 20V35/44G gas engine; Das Brennverfahren des Gasmotors 20V35/44G von MAN

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Markus; Auer, Matthias; Stiesch, Gunnar [MAN Diesel and Turbo SE, Augsburg (Germany)

    2013-04-15

    The new gas engine 20V35/44G by MAN Diesel and Turbo SE has a power output of 10.6 MW. The high effective efficiency level of 48.4 % as well as numerous technical innovations allow an environment-friendly, economical and reliable engine operation. Key to achieve this is the combustion system, which has been optimised during advanced engineering by means of modern simulation tools and extensive single-cylinder tests. (orig.)

  14. Evaluation of turbulent transport and flame surface dissipation using direct numerical simulation of turbulent combustion; Evaluation des termes de transport et de dissipation de surface de flamme par simulation numerique directe de la combustion turbulente

    Energy Technology Data Exchange (ETDEWEB)

    Boughanem, H.

    1998-03-24

    The assumption of gradient transport for the mean reaction progress variable has a limited domain of validity in premixed turbulent combustion. The existence of two turbulent transport regimes, gradient and counter-gradient, is demonstrated in the present work using Direct Numerical Simulations (DNS) of plane flame configurations. The DNS data base describes the influence of the heat release factor, of the turbulence-to-flame velocity ratio, and of an external pressure gradient. The simulations reveal a strong correlation between the regime of turbulent transport and the turbulent flame speed and turbulent flame thickness. These effects re not well described by current turbulent combustion models. A conditional approach `fresh gases / burnt gases` is proposed to overcome these difficulties. Furthermore, he development of flame instabilities in turbulent configurations is also observed in the simulations. A criterion is derived that determines the domain of occurrence of these instabilities (Darrieus- Landau instabilities, Rayleigh- Taylor instabilities, thermo-diffusive instabilities). This criterion suggests that the domain of occurrence of flame instabilities is not limited to small Reynolds numbers. (author) 98 refs.

  15. Combustion noise

    Science.gov (United States)

    Strahle, W. C.

    1977-01-01

    A review of the subject of combustion generated noise is presented. Combustion noise is an important noise source in industrial furnaces and process heaters, turbopropulsion and gas turbine systems, flaring operations, Diesel engines, and rocket engines. The state-of-the-art in combustion noise importance, understanding, prediction and scaling is presented for these systems. The fundamentals and available theories of combustion noise are given. Controversies in the field are discussed and recommendations for future research are made.

  16. Development of reduced kinetic schemes for the description of pollutants formation in combustion; Mise au point de schemas cinetiques reduits pour decrire la formation des polluants dans la combustion

    Energy Technology Data Exchange (ETDEWEB)

    Ferrendier, M.

    1998-12-17

    The typical dimensions of details chemical-kinetic mechanisms proposed to describe combustion systems are too large for multi-dimensional computations applications. The objective of reduction methods is to construct low-dimensional schemes that can be incorporated in industrial codes. We consider here a new class of methods based on a mathematical analysis of the detailed chemical-kinetic mechanisms, and the identification of a low-dimensional manifold that describes the slow dynamics of the chemical system. The mathematical reduction methods considered in this work are the Intrinsic Low Dimensional Manifold (ILDM) method proposed by Maas and Pope (1992), and the Singular Perturbation (PS) method proposed by Duchene and Rouchon (1996). The domain of validity of the ILDM or PS reduced schemes is limited to a high temperature domain T {>=} T{sub c}. This result suggests that ignition is out of the domain of application of reduced mechanisms. In the case of a CO/H{sub 2}/N{sub 2}-air combustion system, and using a two-dimensional slow manifold, we find T{sub c} {approx} 750 K. We also find that for that particular system, 2 progress variables are sufficient for an accurate description of the structure and the velocity of a laminar premixed flame. In the case of a CH{sub 4}-air combustion system, and using a two-dimensional slow manifold, we find T{sub c}{approx}1500 K. We also find that 2 progress variables are insufficient for an accurate description of the structure and the velocity of a laminar premixed flame. The study of the different NO formation mechanisms show that the thermal NO mechanism (the Zeldovich mechanism) is dominant for premixed configurations with lean or stoichiometric conditions ({phi}){>=}1.2), and for non-premixed configurations at high temperatures and high pressures (T{sub air}{>=}1000 K, P {>=} 10 bars). Under these conditions, the MPKIVA sub model used to describe NO formation in the IFP version of the KIVA code performs reasonably well. An

  17. Pollutant emission inventories: contribution of wood combustion in emissions of greenhouse gases and atmospheric pollutants; Inventaires des emissions de polluants: contribution de la combustion bois dans les emissions de gaz a effet de serre et les emissions de polluants classiques

    Energy Technology Data Exchange (ETDEWEB)

    Allemand, N. [CITEPA, 75 - Paris (France)

    2009-03-15

    The use of wood for energy applications has a significant contribution in emissions of some pollutants involved in acidification, eutrophication and ozone formation. The largest contribution is linked to the use of wood in domestic appliances. On contrary, the use of wood for steam and electricity production in industrial and collective heating boilers is reduced. Wood combustion in domestic appliances represents 31% of total emissions for CO, 20,6% for NMVOC, 24,8% for PM{sub 10}, 37,5% for PM{sub 2.5} and 74,1% for 4 HAP in 2006. France must be in compliance with national emission ceilings implemented by the European Directive 2001/81/EC for SO{sub 2}, NO{sub x} and NMVOC in 2010. New ceilings are being prepared by the European Commission for application in 2020. Moreover, a ceiling should be implemented for PM{sub 2.5}. The increase in energy performances of domestic appliances is necessary as well as a large penetration of new appliances with high efficiency and low emissions to remove the oldest ones. The decrease of the energy demand of building and houses is also crucial. Wood combustion in industrial and large collective boilers is carried out in good conditions and emissions are low. Wood is a renewable energy. Its combustion is neutral for CO{sub 2} emissions as it is considered that when emitted, CO{sub 2} is absorbed by vegetation in growth. Wood use is an essential component for contributing to the CO{sub 2} emission reduction by 20% in 2020 compared to 1990 according to objectives fixed by the law project no.1 of the Grenelle of Environment and the European Commission and a proportion of 23% of renewable energy in the final energy consumption. This use must be carried out in well controlled and optimized conditions for avoiding emissions of classical pollutants and a durable management of forests can only enable their sink role for CO{sub 2}. (author)

  18. Processing Th C{sub 2} - UC{sub 2} fuel extracted from high temperature reactors HTGCR; Etude du traitement des combustibles Th C{sub 2} - UC{sub 2} issus de reacteurs a haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Derrien, C.; Lessart, P.; Pianezza, E.; Verry, C.; Villain, G. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1969-07-01

    The object of this investigation is solubilisation head-end (from crushing and grinding phase to non included first purification phase) of pulverulent ({sup 233}U/{sup 232}Th)C{sub 2} (200 - 500 microns diameter) contained in a graphite matrix extracted from a 4.10{sup 13} n.cm{sup -2}.s{sup -1} thermalized neutrons average flux with an irradiation of 80000 MWjT{sup -1} HTGCR reactor. After having succinctly described different bibliographic processes we have chosen the burn - leach of reactor fuel and graphite matrix containing it. The technology of burner is original in nuclear field and still more by utilizing ultra-sounds to intensify burning reaction and to minimize the weight of unburnables. The mixture of ThO{sub 2}, U{sub 3}O{sub 8}, and fission products oxides is solubilized by boiling HNO{sub 3} 13 M + HF 0.05 M. This process is profit-learning in a thorium recuperation and reprocessing point of view. In the contrary-case it would be interesting to consider a dry-process which would permit to separate solid ThF{sub 4} from gaseous UF{sub 6}. (authors) [French] Cette etude a pour objet le traitement initial de mise en solution ou 'head-end' (allant de la phase broyag-concassage a la phase de premiere purification exclue) d'un combustible ({sup 233}U/{sup 232}Th)C{sub 2} pulverulent (de 200 a 500 {mu} de diametre) contenu dans une matrice de graphite issu d'un reacteur HTGCR surgenerateur a neutrons thermiques de flux moyen 4. l0{sup 13} n.cm{sup -2}.s{sup -1} et taux d'irradiation 80000 MWjT{sup -1}. Apres exposition succincte des differents procedes bibliographiques decrits, nous avons finalement choisi le traitement par combustion-attaque ('Burn-Leach') du combustible et de la matrice etanche graphite qui le contient. La technologie du bruleur est originale dans le domaine nucleaire d'autant qu'elle utilise les ultra-sons pour ameliorer le rendement de la reaction de combustion et reduire au minimum le poids

  19. Numerical and experimental study of the influence of the operational parameters on the formation mechanisms of oxides of nitrogen during the combustion of mixtures of cellulosic and plastic materials; Etude experimentale et numerique de l'influence des parametres operatoires sur les mecanismes de formation des oxydes d'azote lors de la combustion de melanges de materiaux cellulosiques et plastiques

    Energy Technology Data Exchange (ETDEWEB)

    Andzi Barhe, T.

    2004-10-15

    The current thesis was performed within a collaboration between the Laboratoire de Combustion et de Detonique (LCD of the University of Poitiers) and the Laboratoire de Physique et de Chimie d'Environnement (LPCE) of the University of Ouagadougou. It was financed by Agency for Environment and Energy Management (ADEME). The principle object of this study is the optimisation of the combustion process during the incineration of waste. This optimisation is aimed at the reduction of the polluting emissions, principally CO and NO, during the incineration of cellulosic and plastic materials. It involves the analysis of the influence of the operational parameters on the polluting emissions and the control of reaction mechanisms of formation and reduction of these pollutants during the combustion process. Consequently, the study was performed in two parts: an experimental part and a numerical part. The experimental part was realised using a fixed bed counterflow reactor. This setup simulates the combustion within an industrial waste incinerator. The reactor allows the combustion of a vertical layer of waste mixture (wood, cardboard, PET, polyamide) to be followed. Three model mixtures representative of the makeup of household waste were studied in order to determine the influence of the composition of the waste on the emission of pollutants (CO and NO). The obtained results show that this parameter has a practically negligible influence within the tested parameter range. Consequently the formation of pollutants depends on the operating parameters - the equivalence ratio and the temperature. A numerical study of the influence of these parameters in order to show their impact on the mechanisms of pollutant formation and to determine the chemical mechanisms involved in the formation of oxides of nitrogen. The numerical study was performed with software developed at the LCD. This programme based on a detailed chemical model coupled to a simple physical model. It uses the

  20. The Role of Attrition and Solids Recovery in a Chemical Looping Combustion Process; Effet de l'attrition et de la recuperation des particules dans le procede de combustion en boucle chimique

    Energy Technology Data Exchange (ETDEWEB)

    Kramp, M.; Thon, A.; Hartge, E.U.; Heinrich, S.; Werther, J. [Institute of Solids Process Engineering and Particle Technology, Hamburg University of Technology, 21071 Hamburg (Germany)

    2011-03-15

    In the present work, the steady-state behavior of a Chemical Looping Combustion process of interconnected fluidized bed reactors is simulated. The simulations have been carried out in two different scales, 50 kWth and 100 MWth. Attrition model derived from small scale laboratory experiments has been employed for the prediction of the process behavior in terms of attrition and Oxygen Carrier loss. Information on Oxygen Carrier characteristics and reaction kinetics were taken from literature. Realistic circulation mass flows of Oxygen Carrier particles are obtained and Oxygen Carrier losses are quantified. The large scale process looses significantly more Oxygen Carrier than the small scale process based on the same amount of thermal energy produced. Incomplete conversion in the air reactor could be identified as a critical point. Another issue is the fuel gas bypassing the Oxygen Carrier particles through bubbles in the large scale process which leads to lowered fuel conversions. The simulations indicate that a similar performance of a pilot scale and a large scale process is not guaranteed due to the scale-up effect on fluid dynamics. Furthermore, the simulations allow an assessment of the influence of the quality of the solids recovery system on the Oxygen Carrier loss. The distribution of the losses between possible origins is investigated and different changes in the solids recovery system are discussed regarding their potential to decrease the Oxygen Carrier loss. For example, the addition of a second-stage cyclone after the air reactor of the large scale process reduces the Oxygen Carrier loss significantly. (authors)

  1. Combustion engineering

    CERN Document Server

    Ragland, Kenneth W

    2011-01-01

    Introduction to Combustion Engineering The Nature of Combustion Combustion Emissions Global Climate Change Sustainability World Energy Production Structure of the Book   Section I: Basic Concepts Fuels Gaseous Fuels Liquid Fuels Solid Fuels Problems Thermodynamics of Combustion Review of First Law Concepts Properties of Mixtures Combustion StoichiometryChemical EnergyChemical EquilibriumAdiabatic Flame TemperatureChemical Kinetics of CombustionElementary ReactionsChain ReactionsGlobal ReactionsNitric Oxide KineticsReactions at a Solid SurfaceProblemsReferences  Section II: Combustion of Gaseous and Vaporized FuelsFlamesLaminar Premixed FlamesLaminar Flame TheoryTurbulent Premixed FlamesExplosion LimitsDiffusion FlamesGas-Fired Furnaces and BoilersEnergy Balance and EfficiencyFuel SubstitutionResidential Gas BurnersIndustrial Gas BurnersUtility Gas BurnersLow Swirl Gas BurnersPremixed-Charge Engine CombustionIntroduction to the Spark Ignition EngineEngine EfficiencyOne-Zone Model of Combustion in a Piston-...

  2. Presentation of the health impact evaluation study of atmospheric emissions of a major coal combustion installation; Mise a jour de l'etude d'evaluation de l'impact sur la sante des rejets atmospheriques des tranches charbon d'une grande installation de combustion

    Energy Technology Data Exchange (ETDEWEB)

    Bonnard, R

    2004-12-15

    In the framework of a working group on the major installations, a study has been realized on a today coal combustion installation. The direct risk by inhalation and the risks bond to indirect exposure of atmospheric releases were analyzed. The calculation method is explained and the uncertainties are discussed to present the results. (A.L.B.)

  3. La pulvérisation du fuel oïl lourd par des combustibles gazeux Using Gaseous Fuels to Spray Heavy Fuel Oil

    Directory of Open Access Journals (Sweden)

    Ladurelli A.

    2006-11-01

    Full Text Available Pour faciliter l'inflammation du fuel lourd on procède à sa pulvérisation au droit du brûleur. Deux méthodes sont généralement employées à cet effet : - La pulvérisation mécanique qui consiste à faire passer le liquide sous forte pression au travers d'orifices calibrés de petit diamètre. - La pulvérisation pneumatique qui consiste à utiliser la détente d'un fluide auxiliaire préalablement comprimé. Les fluides couramment utilisés pour cela sont l'air comprimé et la vapeur d'eau ; toutefois tous les combustibles gazeux, notamment le gaz naturel et les gaz de raffinerie, peuvent également servir de fluide de pulvérisation quand ils sont disponibles sous pression. The igniting of heavy fuel oil is facilitated by spraying it at the burner. Two methods are used as a rule: - Pressure atomization, consisting in causing the liquid to pass at high pressure through calibrated small-diameter orifices. - Twin-fluid atomization, which consists in using the expansion of a previously compressed auxiliary fluid. The fluids commonly used for the purpose are compressed air and steam. However, any gaseous fuel, particularly natural gas and the refinery gases, can be used as the spraying fluid provided it is available under pressure.

  4. Analytic studies on pollutant deposition through domestic coal combustion - influence of the current structural change on pollution in an urban region. Final report; Analytische Untersuchungen zum Schadstoffeintrag durch den Hausbrand - Auswirkungen des gegenwaertigen Strukturwandels auf die urbane Belastungssituation. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Engewald, W.; Knobloch, T.; Asperger, A.

    1996-12-31

    In the present paper the author reports on the continuation of an OEKOR part project in which he had undertaken a chemical characterisation of emissions from domestic brown coal combustion. On the basis of a partitioning by land use of the Greater Leipzig region he initiated long-term observations of local pollution levels for the various structural types of land. The aim of the work was to facilitate a comprehensive analysis of local air quality in terms of VOC levels. The current concern about VOCs results from the toxicological risk they have been proven to pose to the human organism and from their relevance to the chemistry of the atmosphere (e.g., as precursors of ground-level ozone and other oxidising agents). The task to be accomplished was broken down into the following main steps: Development and trial of a sampling and analysis method for determining an as wide a spectrum of environmental VOCs as possible; elaboration of a measuring strategy for obtaining results of high representativeness and power; installation and operation of pollution monitoring sites in selected structural types of area characteristic of Leipzig; execution of measuring campaigns of several weeks each at selected sites during both winter and summer periods. (orig./MSK) [Deutsch] In Fortsetzung eines vom Berichterstatter bearbeiteten OeKOR-Teilprojekts zur chemischen Charakterisierung von Emissionen aus dem Hausbrand von Braunkohle galt es, auf der Basis einer an der Flaechennutzung ausgerichteten Untergliederung der Stadtregion Leipzig in unterschiedliche Strukturtypen langfristige Immissionsbeobachtungen zu beginnen mit dem Ziel, eine Zustandsanalyse des Umweltmediums Luft bezueglich des Gehalts an fluechtigen organischen Verbindungen (VOC) in ihrer gesamten Breite zu ermoeglichen. Das verstaerkte Interesse an diesen Verbindungen resultiert aus dem fuer eine Reihe von VOC belegten toxikologischen Gefahrenpotential fuer den menschlichen Organismus sowie ihrer atmosphaerenchemischen

  5. Emission inventory for large combustion plants in France according to the 2001/80/CE European directive - LCP - February 2010; Inventaire des emissions des grandes installations de combustion en France en application de la directive europeenne 2001/80/CE - GIC - Fevrier 2010

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Jean-Pierre; Fontelle, Jean-Pierre; Gavel, Antoine; Vincent, Julien; Matthias, Etienne; Druart, Ariane; Jacquier, Guillaume; Nicco, Laetitia

    2010-02-15

    After a recall of the methodological aspects of this inventory (scope of application, concept of existing or new installation, thermal power, fuels, considered pollutants, equipment, data acquisition and processing), this report presents the national results: typology of large combustion plant (LCP) installations, energy consumption, atmospheric emissions (sulphur dioxide, nitrogen dioxide, particles), emission distribution per energy type, sector-based distribution of LCPs. It also presents regional results (for 2008 and evolutions in 2009)

  6. The Role of Attrition and Solids Recovery in a Chemical Looping Combustion Process Effet de l’attrition et de la récupération des particules dans le procédé de combustion en boucle chimique

    Directory of Open Access Journals (Sweden)

    Kramp M.

    2011-05-01

    Full Text Available In the present work, the steady-state behavior of a Chemical Looping Combustion process of interconnected fluidized bed reactors is simulated. The simulations have been carried out in two different scales, 50 kWth and 100 MWth. Attrition model derived from small scale laboratory experiments has been employed for the prediction of the process behavior in terms of attrition and Oxygen Carrier loss. Information on Oxygen Carrier characteristics and reaction kinetics were taken from literature. Realistic circulation mass flows of Oxygen Carrier particles are obtained and Oxygen Carrier losses are quantified. The large scale process looses significantly more Oxygen Carrier than the small scale process based on the same amount of thermal energy produced. Incomplete conversion in the air reactor could be identified as a critical point. Another issue is the fuel gas bypassing the Oxygen Carrier particles through bubbles in the large scale process which leads to lowered fuel conversions. The simulations indicate that a similar performance of a pilot scale and a large scale process is not guaranteed due to the scale-up effect on fluid dynamics. Furthermore, the simulations allow an assessment of the influence of the quality of the solids recovery system on the Oxygen Carrier loss. The distribution of the losses between possible origins is investigated and different changes in the solids recovery system are discussed regarding their potential to decrease the Oxygen Carrier loss. For example, the addition of a second-stage cyclone after the air reactor of the large scale process reduces the Oxygen Carrier loss significantly. Le présent travail propose un modèle de simulation en continu du procédé de combustion en boucle chimique constitué de deux lits fluidisés interconnectés. Les simulations ont été conduites à deux échelles 50 kWth correspondant à une installation pilote et 100 MWth correspondant à une installation industrielle. Un modèle d

  7. Application des modèles mécanistiques de cinétique chimique aux combustions industrielles. Illustration par la fabrication du gaz de synthèse Application of Mechanistic Models of Chemical Kinetics to Industrial Combustion. Illustration by Synthetic Gas Manufacturing

    Directory of Open Access Journals (Sweden)

    Gateau P.

    2006-11-01

    Full Text Available En combustion, la formation d'espèces mineures clés, comme les polluants, peut être interprétée par des modèles mécanistiques de cinétique chimique. Les informations que fournissent ces modèles, même s'il ne s'agit que de tendances, sont suffisamment fiables pour définir des choix technologiques. Toutefois, compte-tenu de la complexité des phénomènes traités, leur emploi fait appel à une méthode indirecte décrite dans cet article et illustrée par la conception d'un réacteur autotherme destiné à la préparation d'un syngaz (gaz de synthèse. Dans l'exemple proposé comme application, l'objectif est de faire fonctionner à l'air un réacteur opérant actuellement à l'oxygène pur. Le modèle mécanistique choisi établit très clairement les contraintes imposées par ce choix. During the development of a partial combustion reactor for natural gas [1], Institut Français du Pétrole (IFP has made use of a mechanistic model to determine the impact of operational parameters on the formation of soot. The model we chose deals with the oxidation and pyrolysis of light hydrocarbons by several hundred elementary reactions, some of which are shown in Table 1. All the species taken into consideration as well as their linking are shown in the flowchart in Fig. 3. Our data mainly came from References [2] and [8], from which we took all the reactions of species having three carbon atoms or less as well as the pyrolysis reactions of hydrocarbons with four carbon atoms. In this database, the kinetic coefficients of reactions between CH4 and the C2H5, C2H3 and C2H radicals were replaced by the values published in Reference [9]. This set of reactions is not sufficient to analyze the formation of soot, and so we added on the pyrolysis reactions of acetylene from Reference [10]. The model assimilated the total mass of carbon contained in C5 and C6 hydrocarbons with a soot number assumed to be proportional to the mass of soot formed by the

  8. Combustion physics

    Science.gov (United States)

    Jones, A. R.

    1985-11-01

    Over 90% of our energy comes from combustion. By the year 2000 the figure will still be 80%, even allowing for nuclear and alternative energy sources. There are many familiar examples of combustion use, both domestic and industrial. These range from the Bunsen burner to large flares, from small combustion chambers, such as those in car engines, to industrial furnaces for steel manufacture or the generation of megawatts of electricity. There are also fires and explosions. The bountiful energy release from combustion, however, brings its problems, prominent among which are diminishing fuel resources and pollution. Combustion science is directed towards finding ways of improving efficiency and reducing pollution. One may ask, since combustion is a chemical reaction, why physics is involved: the answer is in three parts. First, chemicals cannot react unless they come together. In most flames the fuel and air are initially separate. The chemical reaction in the gas phase is very fast compared with the rate of mixing. Thus, once the fuel and air are mixed the reaction can be considered to occur instantaneously and fluid mechanics limits the rate of burning. Secondly, thermodynamics and heat transfer determine the thermal properties of the combustion products. Heat transfer also plays a role by preheating the reactants and is essential to extracting useful work. Fluid mechanics is relevant if work is to be performed directly, as in a turbine. Finally, physical methods, including electric probes, acoustics, optics, spectroscopy and pyrometry, are used to examine flames. The article is concerned mainly with how physics is used to improve the efficiency of combustion.

  9. Biofuels Combustion

    Science.gov (United States)

    Westbrook, Charles K.

    2013-04-01

    This review describes major features of current research in renewable fuels derived from plants and from fatty acids. Recent and ongoing fundamental studies of biofuel molecular structure, oxidation reactions, and biofuel chemical properties are reviewed, in addition to combustion applications of biofuels in the major types of engines in which biofuels are used. Biofuels and their combustion are compared with combustion features of conventional petroleum-based fuels. Two main classes of biofuels are described, those consisting of small, primarily alcohol, fuels (particularly ethanol, n-butanol, and iso-pentanol) that are used primarily to replace or supplement gasoline and those derived from fatty acids and used primarily to replace or supplement conventional diesel fuels. Research efforts on so-called second- and third-generation biofuels are discussed briefly.

  10. Biofuels combustion.

    Science.gov (United States)

    Westbrook, Charles K

    2013-01-01

    This review describes major features of current research in renewable fuels derived from plants and from fatty acids. Recent and ongoing fundamental studies of biofuel molecular structure, oxidation reactions, and biofuel chemical properties are reviewed, in addition to combustion applications of biofuels in the major types of engines in which biofuels are used. Biofuels and their combustion are compared with combustion features of conventional petroleum-based fuels. Two main classes of biofuels are described, those consisting of small, primarily alcohol, fuels (particularly ethanol, n-butanol, and iso-pentanol) that are used primarily to replace or supplement gasoline and those derived from fatty acids and used primarily to replace or supplement conventional diesel fuels. Research efforts on so-called second- and third-generation biofuels are discussed briefly.

  11. Turbulent combustion

    Energy Technology Data Exchange (ETDEWEB)

    Talbot, L.; Cheng, R.K. [Lawrence Berkeley Laboratory, CA (United States)

    1993-12-01

    Turbulent combustion is the dominant process in heat and power generating systems. Its most significant aspect is to enhance the burning rate and volumetric power density. Turbulent mixing, however, also influences the chemical rates and has a direct effect on the formation of pollutants, flame ignition and extinction. Therefore, research and development of modern combustion systems for power generation, waste incineration and material synthesis must rely on a fundamental understanding of the physical effect of turbulence on combustion to develop theoretical models that can be used as design tools. The overall objective of this program is to investigate, primarily experimentally, the interaction and coupling between turbulence and combustion. These processes are complex and are characterized by scalar and velocity fluctuations with time and length scales spanning several orders of magnitude. They are also influenced by the so-called {open_quotes}field{close_quotes} effects associated with the characteristics of the flow and burner geometries. The authors` approach is to gain a fundamental understanding by investigating idealized laboratory flames. Laboratory flames are amenable to detailed interrogation by laser diagnostics and their flow geometries are chosen to simplify numerical modeling and simulations and to facilitate comparison between experiments and theory.

  12. Cojoncture énergétique et recherches en combustion The Energy Situation and Research on Combustion

    Directory of Open Access Journals (Sweden)

    Balaceanu J. -C.

    2006-11-01

    Full Text Available Les progrès de la combustion ont contribué de façon décisive à l'évolution de la technique humaine. Face à cette importance de la combustion, l'auteur présente un certain nombre d'éléments concernant l'avenir prévisible des combustibles fossiles et de leurs usages. Les différents composants de la conjoncture énergétique en matière de combustibles imposent deux impératifs : le respect de l'environnement et la conservation de l'énergie fossile. De cet ensemble de considérations, on tire des conclusions quant à l'évolution des techniques de combustion et, de là, quant aux thèmes de recherche appliquée et à l'élucidation nécessaire des mécanismes fondamentaux. Advances in combustion have decisively contributed to the evolution of human technology. Concerning the importance of combustion, this article describes various aspects of the foreseeable future of fossil fuels and their uses. The different composants of the energy situation with regard to fuels impose two requirements - respect for the environment and fossil energy conservation. From ail these considerations conclusions are drawn as to the evolution of fuel techniques and thence with regard to topics of applied research and the necessary elucidation of fundamental mechanisms.

  13. Tubular combustion

    CERN Document Server

    Ishizuka, Satoru

    2014-01-01

    Tubular combustors are cylindrical tubes where flame ignition and propagation occur in a spatially confined, highly controlled environment, in a nearly flat, elongated geometry. This allows for some unique advantages where extremely even heat dispersion is required over a large surface while still maintaining fuel efficiency. Tubular combustors also allow for easy flexibility in type of fuel source, allowing for quick changeover to meet various needs and changing fuel pricing. This new addition to the MP sustainable energy series will provide the most up-to-date research on tubular combustion--some of it only now coming out of private proprietary protection. Plentiful examples of current applications along with a good explanation of background theory will offer readers an invaluable guide on this promising energy technology. Highlights include: * An introduction to the theory of tubular flames * The "how to" of maintaining stability of tubular flames through continuous combustion * Examples of both small-scal...

  14. Advanced Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, Gordon R. [NETL

    2013-03-11

    The activity reported in this presentation is to provide the mechanical and physical property information needed to allow rational design, development and/or choice of alloys, manufacturing approaches, and environmental exposure and component life models to enable oxy-fuel combustion boilers to operate at Ultra-Supercritical (up to 650{degrees}C & between 22-30 MPa) and/or Advanced Ultra-Supercritical conditions (760{degrees}C & 35 MPa).

  15. Combustion en lit fluidisé Fluidized-Bed Combustion

    Directory of Open Access Journals (Sweden)

    Chrysostome G.

    2006-11-01

    Full Text Available Après quelques rappels généraux sur la fluidisation où seront présentés en par-ticulier les avantages qu'elle offre en combustion, on exposera l'état actuel du développement des générateurs à lit fluidisé opérant avec les combustibles suivants : charbon, combustibles pétroliers, résidus divers ; il sera fait mention de la contribution de l'Institut Français du Pétrole (IFP dans les deux derniers domaines.On présentera ensuite les installations les plus récentes en traitement de minerais (grillage des sulfures, calcination de calcaires. En raison de son importance on examinera encore les possibilités de désulfuration au sein de lits fluidisés, de même que seront commentés les travaux de régénération des absorbants.On terminera enfin en mentionnant les développements des lits circulants ou rapides, considérés comme les réacteurs de la seconde génération. After a general review of fluidization including in particular the advantages it offers for combustion, this article describes the present state of the development of fluidized-bed gcnerators operating with the following fuels : cool, petroleum fuels, different residues. Mention is made of Institut Français du Pétrole (IFP contribution in the last two fields. Then the most recent ore-treating installations are described (roasting of sulfides, calcination of limestones. Because of its importance, the possibilities of desulfurizoticn inside fluidized beds is examined, and research on the regeneration of absorbants is commented on. The article ends by mentioning the development of circulating or fast beds which are considered as second generation reactors.

  16. Physically founded modelling of transient heat transfer in diesel engine combustion chambers with application of 3D-CFD calculations. Final report; Physikalisch fundierte Modellierung des instationaeren Wandwaermeueberganges im Brennraum von Dieselmotoren mit Applikation an 3D-CFD-Rechnungen. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Merker, G.P.; Lettmann, H.

    2003-05-01

    A phenomenological wall heat transfer model was developed for diesel engines, enhanced for application of the 3D-CFC code KIVA-3V, and implemented in the code. Further, the heat flow was measurement near the cylinder head, bushel and piston of a DI one-cylinder experimental diesel engine. The influence of soot radiation and convective heat transfer on the wall are modelled separately. The insulating effect of soot deposits on the walls during engine operation is taken into acount as well. The multizone model and the 3D model are in good agreement with the models by Han and Reitz (1997) and with experimental findings. The spatial resolution of heat flow at the wall further shows that both the radiative and convective heat flow are strongly locally dependent. The model presents a physically correct description of the heat flow at the wall of a diesel engine combustion chamber. [German] Im Rahmen des gesamten Forschungsvorhabens wurden ein phaenomenologisches Wandwaermeuebergangsmodell fuer Dieselmotoren entwickelt, dieses wurde fuer die Anwendung in den 3D-CFD-Code KIVA-3V erweitert und in den Code implementiert. Zusaetzlich sind Waermestrommessungen im Brennraum an Zylinderkopf, Laufbuchse und Kolben durchgefuehrt worden. Dafuer stand ein direkteinspritzender Einzylinder-Versuchsdieselmotor zur Verfuegung. Das im Rahmen dieses Vorhabens entwickelte Waermeuebergangsmodell bildet den Einfluss der Russstrahlung und des konvektiven Wandwaermeueberganges separat ab. Die isolierende Wirkung von Russwandablagerungen waehrend des gefeuerten Motorbetriebes wird dabei ebenfalls beruecksichtigt. Das Mehrzonenmodell sowie das 3D-Modell zeigen sehr gute Uebereinstimmungen des raeumlich gemittelten Wandwaermestroms mit den Modellen von Han und Reitz (1997) und den experimentellen Ergebnissen. Die raeumliche Aufloesung der Wandwaermestroeme zeigt weiter, dass auf der Brennraumoberflaeche die Strahlungswaermestroeme und die konvektiven Waermestroeme stark ortsabhaengig sind. Damit

  17. The Future Contribution of Unconventional Sources of Natural Uranium to Nuclear Fuel Supply. Contribution future des sources conventionnelles d'uranium naturel à l'approvisionnement en combustible nucléaire

    Directory of Open Access Journals (Sweden)

    Boyd B. W.

    2006-11-01

    Full Text Available From what we know about the distribution of uranium in the earth's crust, we can get an indication of how much uranium is likely to occur at concentrations higher than 300 ppm. Although only part of this material is likely to be discovered and brought to production, the amounts are great enough to make it unlikely that much uranium from lower grade deposits will be mined in the next 40 or so years except in special cases. In some circumstances, low grade uranium can be recovered as a by-product or as a product of reworked tailings. Significant amounts are forecast to be recovered from tailings, phosphoric acid and copper leach liquors. It can also be speculated that some uranium may be recovered from coals, shales, granites or carbonatites grading less than 300 ppm. Production from sources in this latter group or from seawater, where uranium would be the prime product, appears unlikely considering the amount of uranium thought to occur in higher concentrotions. De nos connaissances sur la distribution de l'uranium dans la croûte terrestre nous pouvons tirer des indications sur la quantité d'uranium qu'on peut trouver à des concentrations supérieures à 300 ppm. Quoiqu'une partie seulement de celles-ci soit à même d'être découverte et mise en exploitation, les quantités en sont suffisamment grandes pour rendre peu probable l'exploitation des gisements à une teneur plus faible, dans les quarante années à venir ou presque, sauf dans des cas spéciaux. Sous certaines conditions l'uranium à basse teneur peut être récupéré comme sous-produit ou comme produit du retraitement des résidus (tailings et du traitement de l'acide phosphorique et des solutions de lixiviation des minerais de cuivre. On peut aussi prévoir qu'il sera possible d'extraire de l'uranium des charbons, schistes, granites ou carbonatites à une teneur inférieure à 300 ppm. La production à partir des sources de ce dernier groupe ou de l'eau de mer, où l

  18. High Combustion Research Facility

    Data.gov (United States)

    Federal Laboratory Consortium — At NETL's High-Pressure Combustion Research Facility in Morgantown, WV, researchers can investigate new high-pressure, high-temperature hydrogen turbine combustion...

  19. Combustion Research Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Combustion Research Laboratory facilitates the development of new combustion systems or improves the operation of existing systems to meet the Army's mission for...

  20. Avantages des biodigesteurs sur le bois de chauffe dans les ...

    African Journals Online (AJOL)

    Il est également constaté une réduction de la fréquence des pathologies respiratoires et oculaires mais aussi des dépenses pour l'achat de combustible et de compost. Mots clés: Biogaz ; bois ; élevages laitiers ; économie des ménages ; Kaolack ; Sénégal. Biodigester benefits on wood heating in dairy farming of Kaolack ...

  1. Combustion chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Brown, N.J. [Lawrence Berkeley Laboratory, CA (United States)

    1993-12-01

    This research is concerned with the development and use of sensitivity analysis tools to probe the response of dependent variables to model input variables. Sensitivity analysis is important at all levels of combustion modeling. This group`s research continues to be focused on elucidating the interrelationship between features in the underlying potential energy surface (obtained from ab initio quantum chemistry calculations) and their responses in the quantum dynamics, e.g., reactive transition probabilities, cross sections, and thermal rate coefficients. The goals of this research are: (i) to provide feedback information to quantum chemists in their potential surface refinement efforts, and (ii) to gain a better understanding of how various regions in the potential influence the dynamics. These investigations are carried out with the methodology of quantum functional sensitivity analysis (QFSA).

  2. The Use of Fuel Gas as Stripping Medium in Atmospheric Distillation of Crude Oil L’utilisation de gaz combustible comme moyen d’extraction des fractions légères en distillation atmosphérique du pétrole brut

    Directory of Open Access Journals (Sweden)

    Plellis-Tsaltakis C.

    2011-09-01

    Full Text Available Stripping of petroleum fractions aims to remove the light ends that spoil some of their properties, such as the flash point. Stripping usually employs steam for that purpose. Except for steam, other substances can perform the same function, among them light hydrocarbons. In this article, we investigate the use of refinery fuel gas as stripping medium for a crude oil atmospheric distillation unit. L’extraction des fractions légères du pétrole vise à enlever les produits nuisibles à certaines propriétés comme le point d’éclair. Cette opération utilise habituellement de la vapeur d’eau. D’autres substances peuvent remplir la même fonction, comme les hydrocarbures légers. Dans cet article, on étudie l’utilisation du gaz combustible de la raffinerie comme moyen d’extraction des fractions légères dans une unité de distillation atmosphérique.

  3. Equation for Combustion Noise

    Science.gov (United States)

    Liu, T. M.

    1982-01-01

    Mathematical relationship derived for interactions between turbulent flame and combustion noise. Relationship is rigorous theoretical correlation of combustion noise and combustion process. Establishes foundation for acoustic measurements as tool for investigating structure of turbulent flames. Mathematical relationship is expected to aid researchers in field of noise generated by combustion.

  4. Direct numerical simulation of two-phases turbulent combustion: application to study of propagation and structure of flames; Simulation numerique directe de la combustion turbulente diphasique: application a l'etude de la propagation et de la structure des flammes

    Energy Technology Data Exchange (ETDEWEB)

    Canneviere, K.

    2003-12-15

    This work is devoted to the study of the propagation and the structure of two-phases turbulent flames. To this end, Direct Numerical Simulations (DNS) are used. First, numerical systems for two-phases flow simulations is presented along with a specific chemical model. Then, a study of laminar spray flames is carried out. An analytical study related to the dynamics of evaporation of droplets is first proposed where the influence on the equivalence ratio of the ratio between the heating delay of the droplet and the evaporation delay is detailed. The simulation of a propagating flame through a cloud of droplets is carried out and a pulsating behavior is highlighted. A study of these flames according to the topology of liquid fuel enabled us to characterize a double flame structure composed of a premixed flame and a diffusion flame. Our last study is devoted to spray turbulent flames. Two-phase combustion of turbulent jets has been simulated. By varying the spray injection parameters (density, equivalence ratio), a database has been generated. This database allowed us to describe local and global flame regimes appearing in the combustion of sprays. They have been categorized in four main structures: open and closed external regime, group combustion and mixed combustion. Eventually, a combustion diagram has been developed. It involves the spray vaporization time, the mean inter-space between droplets or group of droplets and eventually the injected equivalence ratio. (author)

  5. Oxygen-enhanced combustion

    CERN Document Server

    Baukal, Charles E

    2013-01-01

    Combustion technology has traditionally been dominated by air/fuel combustion. However, two developments have increased the significance of oxygen-enhanced combustion-new technologies that produce oxygen less expensively and the increased importance of environmental regulations. Advantages of oxygen-enhanced combustion include less pollutant emissions as well as increased energy efficiency and productivity. Oxygen-Enhanced Combustion, Second Edition compiles information about using oxygen to enhance industrial heating and melting processes. It integrates fundamental principles, applications, a

  6. Contribution to the study of influence of hydrodynamic conditions on the combustion of a preliminary mixture in a enclosed medium; Contribution a l`etude de l`influence des conditions hydrodynamiques sur la combustion d`un melange prealable dans un milieu confine

    Energy Technology Data Exchange (ETDEWEB)

    Henry, J.D.

    1996-02-01

    This thesis is a study on the internal combustion of a pistons engine. the first chapter is devoted to the description of the experimental device and measurement means. The combustion chamber is described with its adaptation to new experimental conditions. The second chapter concerns the diagnosis means to interpret the hydrodynamic conditions by the cross checking of displays with the measures of flow speed by laser velocimetry. The third chapter gives the result of analysis on the process of the birth of a turbulent flow in a whirl movement. The study of the electric spark and the initial phase of the combustion, in media with or without movement, is in the last chapter. (N.C.)

  7. Modélisation zéro-D des écoulements à l'admission d'un moteur à combustion interne. Application au boîtier papillon et au refroidisseur d’air suralimenté.

    OpenAIRE

    Haddad, Elie

    2017-01-01

    The modeling of an internal combustion engine is an essential step in the process of evaluation of the engine’s performance before using an engine test bench. The simulation allows saving time and costs, which would otherwise result from all the experimental procedures likethe use of sensors, the mounting and dismounting of parts and the operational cost of an engine test bench. Nonetheless, it is essential to have a reliable simulation model that can reproduce the engine’s behavior accuratel...

  8. Combustion 2000

    Energy Technology Data Exchange (ETDEWEB)

    A. Levasseur; S. Goodstine; J. Ruby; M. Nawaz; C. Senior; F. Robson; S. Lehman; W. Blecher; W. Fugard; A. Rao; A. Sarofim; P. Smith; D. Pershing; E. Eddings; M. Cremer; J. Hurley; G. Weber; M. Jones; M. Collings; D. Hajicek; A. Henderson; P. Klevan; D. Seery; B. Knight; R. Lessard; J. Sangiovanni; A. Dennis; C. Bird; W. Sutton; N. Bornstein; F. Cogswell; C. Randino; S. Gale; Mike Heap

    2001-06-30

    . To achieve these objectives requires a change from complete reliance of coal-fired systems on steam turbines (Rankine cycles) and moving forward to a combined cycle utilizing gas turbines (Brayton cycles) which offer the possibility of significantly greater efficiency. This is because gas turbine cycles operate at temperatures well beyond current steam cycles, allowing the working fluid (air) temperature to more closely approach that of the major energy source, the combustion of coal. In fact, a good figure of merit for a HIPPS design is just how much of the enthalpy from coal combustion is used by the gas turbine. The efficiency of a power cycle varies directly with the temperature of the working fluid and for contemporary gas turbines the optimal turbine inlet temperature is in the range of 2300-2500 F (1260-1371 C). These temperatures are beyond the working range of currently available alloys and are also in the range of the ash fusion temperature of most coals. These two sets of physical properties combine to produce the major engineering challenges for a HIPPS design. The UTRC team developed a design hierarchy to impose more rigor in our approach. Once the size of the plant had been determined by the choice of gas turbine and the matching steam turbine, the design process of the High Temperature Advanced Furnace (HITAF) moved ineluctably to a down-fired, slagging configuration. This design was based on two air heaters: one a high temperature slagging Radiative Air Heater (RAH) and a lower temperature, dry ash Convective Air Heater (CAH). The specific details of the air heaters are arrived at by an iterative sequence in the following order:-Starting from the overall Cycle requirements which set the limits for the combustion and heat transfer analysis-The available enthalpy determined the range of materials, ceramics or alloys, which could tolerate the temperatures-Structural Analysis of the designs proved to be the major limitation-Finally the commercialization

  9. Kinetic Deuterium Isotope Effects in the Combustion of Formulated Nitramine Propellants

    Science.gov (United States)

    1994-01-01

    beobachteten Isotopie -Effekte combustion, les effets d’isotopie observes montrent clairement que la - naheliegend, daBl das Aufbrechen der CH-Bindung im...con"rJer la vitesse lors de la combustion du propergol. i base IM) Nitramintreibstoffe ist. Die beobacbteten Werte des Isotopie -Effektes de nitramine

  10. Reduced NOX combustion method

    International Nuclear Information System (INIS)

    Delano, M.A.

    1991-01-01

    This patent describes a method for combusting fuel and oxidant to achieve reduced formation of nitrogen oxides. It comprises: It comprises: heating a combustion zone to a temperature at least equal to 1500 degrees F.; injecting into the heated combustion zone a stream of oxidant at a velocity within the range of from 200 to 1070 feet per second; injecting into the combustion zone, spaced from the oxidant stream, a fuel stream at a velocity such that the ratio of oxidant stream velocity to fuel stream velocity does not exceed 20; aspirating combustion gases into the oxidant stream and thereafter intermixing the aspirated oxidant stream and fuel stream to form a combustible mixture; combusting the combustible mixture to produce combustion gases for the aspiration; and maintaining the fuel stream substantially free from contact with oxidant prior to the intermixture with aspirated oxidant

  11. Gazéification de la biomasse en double lit fluidisé circulant : étude des réactions élémentaires de gazéification et de combustion du char et de reformage des goudrons

    OpenAIRE

    Morin, Mathieu Pierre

    2017-01-01

    La conversion thermochimique à haute température (>700°C) de la biomasse en double lit fluidisé circulant est une voie alternative aux énergies fossiles (pétrole, charbon) pour la production d’un gaz de synthèse à haute valeur énergétique, utilisable dans de nombreuses applications. L’objectif de cette thèse est de développer des méthodologies et des outils théoriques et expérimentaux permettant d’accéder aux cinétiques des transformations élémentaires (pyrolyse de la biomasse, gazéification ...

  12. Combustion Research Facility

    Data.gov (United States)

    Federal Laboratory Consortium — For more than 30 years The Combustion Research Facility (CRF) has served as a national and international leader in combustion science and technology. The need for a...

  13. Utilisation de produits organiques oxygénés comme carburants et combustibles dans les moteurs. Deuxième partie : Les différentes filières d'obtention des carburols. Analyse technico-économique Using Oxygenated Organic Products As Fuels in Engines. Part Two: Different Systems for Producing Alcohol Fuels. Technico-Economic Analysis

    Directory of Open Access Journals (Sweden)

    Chauvel A.

    2006-11-01

    Full Text Available Parmi les produits à même d'être substitués aux hydrocarbures pour la constitution des carburants, les composés organiques oxygénés occupent une place prépondérante à cause de leurs caractéristiques favorables à la combustion dans les moteurs, qu'ils soient employés purs ou mélangés (seuls ou à plusieurs aux hydrocarbures, constituants des carburants classiques. Dans cet article, ces composés oxygénés sont désignés sous le nom de carburols. Alors que l'objet de la première partie de l'étude a été d'examiner les conséquences techniques de l'emploi de ces produits sur les circuits de distribution et le fonctionnement des véhicules, il s'agit dans la présente partie d'analyser les caractéristiques technico-économiques de leur fabrication. En particulier, on y aborde successivement les points suivants : - disponibilités en matières premières : ressources fossiles et végétales ; - analyse technique des divers modes d'obtention - analyse économique ; - programmes nationaux. Among products that can be substituted for hydrocarbons for producing fuels, oxygenated organic compounds occupy a preponderant position because of their favorable characteristics for combustion in engines whether they are used in a pure form or in mixtures (alone or severally with hydrocarbons which are used to make up conventional fuels. In this article these oxygenated compounds are given the name carburols (alcohol fuels. Whereas the aim of Part 1 was to examine the technical consequences of using such products in distribution circuits and for vehicle operating, Part 2 is an analysis of the technico-economic aspects of manufacturing them. In particular, the following points are taken up successively: (a availabilities of raw materials. fossil and vegetebal resources; (b technical analysis of various production methods; (c economic analysis; (d national programs. Depending on the amounts involved, a distinction is made among alternative

  14. Evaluation des dommages des punaisese( Heteroptera ) et des ...

    African Journals Online (AJOL)

    L'analyse statistique des résultats dans les blocs témoins montre que les punaises occasionnent plus de dommages aux boutons floraux et aux capsules vertes immatures que les chenilles. Sur les jeunes capsules, la moyenne des dommages des punaises et des chenilles reste statistiquement identique. Les traitements ...

  15. Uncertainties in hydrogen combustion

    International Nuclear Information System (INIS)

    Stamps, D.W.; Wong, C.C.; Nelson, L.S.

    1988-01-01

    Three important areas of hydrogen combustion with uncertainties are identified: high-temperature combustion, flame acceleration and deflagration-to-detonation transition, and aerosol resuspension during hydrogen combustion. The uncertainties associated with high-temperature combustion may affect at least three different accident scenarios: the in-cavity oxidation of combustible gases produced by core-concrete interactions, the direct containment heating hydrogen problem, and the possibility of local detonations. How these uncertainties may affect the sequence of various accident scenarios is discussed and recommendations are made to reduce these uncertainties. 40 references

  16. Power Split Strategy for Fuel Cell Hybrid Electric System Stratégie de séparation des flux de puissance pour un système électrique hybride à pile à combustible

    Directory of Open Access Journals (Sweden)

    Di Domenico D.

    2009-11-01

    Full Text Available The power management of a hybrid system composed of a fuel cell, a battery and a DC/DC power converter is developed. A decoupled control strategy is proposed, aimed at balancing the power flow between the stack and the battery and avoiding electrochemical damage due to low oxygen concentration in the fuel cell cathode. The controller is composed of two components. The first controller regulates the compressor, and as a consequence the oxygen supplied to the cathode, via a classic Proportional-Integral controller. The second controller optimally manages the current demanded by the fuel cell and battery via a linear-quadratic control strategy acting on the converter. An Extended Kalman Filter is also designed in order to estimate the battery State of Charge. The closed-loop performance was tested in simulation using a 310th-order system model. Ce papier illustre une stratégie de gestion de puissance pour un système hybride composé d’une pile à combustible, d’une batterie et d’un convertisseur DC/DC. Dans le but d’équilibrer les flux de puissance entre la pile à combustible et la batterie et d’éviter les dégâts causés par une dépression d’oxygène dans le cathode de la pile, un contrôleur découplé est proposé. Ce contrôleur se compose de deux parties. La première, un régulateur proportionnel-intégral, commande le compresseur et, par conséquent, le flux d’oxygène fourni au cathode. La deuxième, un régulateur linéaire-quadratique, gère le courant demandé par la pile à combustible et la batterie. Pour estimer l’état de charge de la batterie, un filtre de Kalman étendu a aussi été conçu. Les performances de la stratégie ont été analysées en simulation avec un modèle de batterie du 310e ordre.

  17. Checking the sealing of fuel elements by helium sweating - case of the reactors G2 (1960); Controle de l'etancheite des elements combustibles par ressuage d'helium - cas du reacteur G2 (1960)

    Energy Technology Data Exchange (ETDEWEB)

    Blanc, B.; D' Orival, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Choumoff, S. [Compagnie Francaise Thomson-Houston, 75 - Paris (France)

    1960-07-01

    The G2 slug is a welded, hermetically sealed unit; the seal is checked by placing the fuel element in a helium atmosphere under pressure, then measuring the quantity of helium it releases in a vessel under vacuum. The theoretical aspect and the conditions of industrial application are reviewed, and the installations described. (author) [French] La cartouche G2 se presente comme un ensemble soude, hermetique; le controle d'etancheite s'effectue en immergeant l'element combustible dans une atmosphere d'helium sous pression puis en mesurant la quantite d'helium qu'il restitue dans une enceinte sous vide. L'aspect theorique et les conditions d'exploitation industrielle sont evoques et les installations decrites. (auteur)

  18. New class of combustion processes

    International Nuclear Information System (INIS)

    Merzhanov, A.G.; Borovinskaya, I.P.

    1975-01-01

    A short review is given of the results of work carried out since 1967 on studying the combustion processes caused by the interaction of chemical elements in the condensed phase and leading to the formation of refractory compounds. New phenomena and processes are described which are revealed when investigating the combustion of the systems of this class, viz solid-phase combustion, fast combustion in the condensed phase, filtering combustion, combustion in liquid nitrogen, spinning combustion, self-oscillating combustion, and repeated combustion. A new direction in employment of combustion processes is discussed, viz. a self-propagating high-temperature synthesis of refractory nitrides, carbides, borides, silicides and other compounds

  19. Opportunities in pulse combustion

    Science.gov (United States)

    Brenchley, D. L.; Bomelburg, H. J.

    1985-10-01

    In most pulse combustors, the combustion occurs near the closed end of a tube where inlet valves operate in phase with the pressure amplitude variations. Thus, within the combustion zone, both the temperature and the pressure oscillate around a mean value. However, the development of practical applications of pulse combustion has been hampered because effective design requires the right combination of the combustor's dimensions, valve characteristics, fuel/oxidizer combination, and flow pattern. Pulse combustion has several additional advantages for energy conversion efficiency, including high combustion and thermal efficiency, high combustion intensity, and high convective heat transfer rates. Also, pulse combustion can be self-aspirating, generating a pressure boost without using a blower. This allows the use of a compact heat exchanger that may include a condensing section and may obviate the need for a chimney. In the last decade, these features have revived interest in pulse combustion research and development, which has resulted in the development of a pulse combustion air heater by Lennox, and a pulse combustion hydronic unit by Hydrotherm, Inc. To appraise this potential for energy savings, a systematic study was conducted of the many past and present attempts to use pulse combustion for practical purposes. The authors recommended areas where pulse combustion technology could possibly be applied in the future and identified areas in which additional R and D would be necessary. Many of the results of the study project derived from a special workshop on pulse combustion. This document highlights the main points of the study report, with particular emphasis on pulse combustion application in chemical engineering.

  20. Matériaux pour la combustion catalytique

    Science.gov (United States)

    Lunot, C.

    2002-04-01

    La combustion catalytique est l'une des technologies les plus prometteuses pour réaliser une combustion ultra-propre des hydrocarbures et notamment du gaz naturel. Aujourd'hui, cependant, les produits commerciaux utilisant cette technologie sont peu nombreux et le plus souvent réservés à des applications basse température (500-700°C) à cause de la limitation liée à la durée de vie des catalyseurs utilisés (métaux précieux). Le développement de cette technologie est donc intimement lié à des défis “matériaux”, et notamment à l'obtention de catalyseurs actifs et durables au moins plusieurs milliers d'heures à des températures comprises entre 700 et 1 100°C. Or les catalyseurs de type métaux précieux, très actifs y compris à basse température, ont une durée de vie (maintien de leur activité catalytique dans le temps) d'autant plus limitée que la température de l'application est élevée. A l'inverse, les catalyseurs de type pérovskite ou hexaaluminate, dont la durée de vie à haute température est satisfaisante, présentent une activité plus faible qui rend notamment l'amorçage de la combustion catalytique délicate. C'est pourquoi les solutions potentielles sont à rechercher non seulement du côté matériaux de catalyseurs mais aussi du côté ingénierie et conception des matériels associés.

  1. Combustion modeling in internal combustion engines

    Science.gov (United States)

    Zeleznik, F. J.

    1976-01-01

    The fundamental assumptions of the Blizard and Keck combustion model for internal combustion engines are examined and a generalization of that model is derived. The most significant feature of the model is that it permits the occurrence of unburned hydrocarbons in the thermodynamic-kinetic modeling of exhaust gases. The general formulas are evaluated in two specific cases that are likely to be significant in the applications of the model.

  2. Lump wood combustion process

    Science.gov (United States)

    Kubesa, Petr; Horák, Jiří; Branc, Michal; Krpec, Kamil; Hopan, František; Koloničný, Jan; Ochodek, Tadeáš; Drastichová, Vendula; Martiník, Lubomír; Malcho, Milan

    2014-08-01

    The article deals with the combustion process for lump wood in low-power fireplaces (units to dozens of kW). Such a combustion process is cyclical in its nature, and what combustion facility users are most interested in is the frequency, at which fuel needs to be stoked to the fireplace. The paper defines the basic terms such as burnout curve and burning rate curve, which are closely related to the stocking frequency. The fuel burning rate is directly dependent on the immediate thermal power of the fireplace. This is also related to the temperature achieved in the fireplace, magnitude of flue gas losses and the ability to generate conditions favouring the full burnout of the fuel's combustible component, which, at once ensures the minimum production of combustible pollutants. Another part of the paper describes experiments conducted in traditional fireplaces with a grate, at which well-dried lump wood was combusted.

  3. Combustion Byproducts Recycling Consortium

    Energy Technology Data Exchange (ETDEWEB)

    Paul Ziemkiewicz; Tamara Vandivort; Debra Pflughoeft-Hassett; Y. Paul Chugh; James Hower

    2008-08-31

    Ashlines: To promote and support the commercially viable and environmentally sound recycling of coal combustion byproducts for productive uses through scientific research, development, and field testing.

  4. Flameless Combustion Workshop

    National Research Council Canada - National Science Library

    Gutmark, Ephraim

    2005-01-01

    .... "Flameless Combustion" is characterized by high stability levels with virtually no thermoacoustic instabilities, very low lean stability limits and therefore extremely low NOx production, efficient...

  5. Research Combustion Laboratory (RCL)

    Data.gov (United States)

    Federal Laboratory Consortium — The Research Combustion Laboratory (RCL) develops aerospace propulsion technology by performing tests on propulsion components and materials. Altitudes up to 137,000...

  6. Turbulent combustion modelization via a tabulation method of detailed kinetic chemistry coupled to Probability Density Function. Application to aeronautical engines; Modelisation de la combustion turbulente via une methode tabulation de la cinetique chimique detaillee couplee a des fonctions densites de probabilite. Application aux foyers aeronautiques

    Energy Technology Data Exchange (ETDEWEB)

    Rullaud, M.

    2004-06-01

    A new modelization of turbulent combustion is proposed with detailed chemistry and probability density functions (PDFs). The objective is to capture temperature and species concentrations, mainly the CO. The PCM-FTC model, Presumed Conditional Moment - Flame Tabulated Chemistry, is based on the tabulation of laminar premixed and diffusion flames to capture partial pre-mixing present in aeronautical engines. The presumed PDFs is introduced to predict averaged values. The tabulation method is based on the analysis of the chemical structure of laminar premixed and diffusion flames. Hypothesis are presented, tested and validated with Sandia experimental data jet flames. Then, the model is introduced in a turbulent flow simulation software. Three configurations are retained to quantify the level of prediction of this formulation: the D and F-Flames of Sandia and lifted jet flames of methane/air of Stanford. A good agreement is observed between experiments and simulations. The validity of this method is then demonstrated. (author)

  7. The taking into account of the MVO{sub 4} (M= La, Ce) - carbon black contact in the catalytic study of the diesel soots combustion; Prise en compte du contact MVO{sub 4} (M= La, Ce) - noir de carbone dans l'evaluation catalytique de la combustion des suies diesel

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen Huu Nhon, Y.; Petit, C. [Laboratoire des Materiaux, Surfaces et Procedes pour la Catalyse (LMSPC), UMR 7515 CNRS ECPM, 67 - Strasbourg (France)

    2004-07-01

    Diesel engines require the use of an exhaust post-treatment system: the particles filter. The success of a catalyzed filter requires the development of a catalyst with a high oxidation capacity in the temperature range 250 - 350 C and a sufficient lifetime in the real running conditions. In this framework, the rare earth vanadate oxides (AVO{sub 4}: A=La, Ce) present a great resistance to the different chemical species such as CO{sub 2}, H{sub 2}O, and SO{sub 2}. The change of different synthesis parameters (preparation method, kind of raw materials, calcination process) has allowed to obtain catalysts having different chemical and physical characters (morphology, specific surface area, apparent volume mass). At first, the performances of the catalysts are evaluated for a pure heterogeneous reaction: the oxidation of gaseous hydrocarbons (methane and propane) to establish their oxidizing power. Then, the contact load is estimated. This requires the perfecting of a study methodology, transposable from the carbon blacks combustion to the diesel soots. In taking again the mixture methods developed by Neeft et al which give either an intimate mixture or a weak mixture between the catalyst and the carbonaceous phase and in playing on the catalyst/carbonaceous phase stoichiometry, the two aspects are estimated. With an intimate mixture, an appropriate classification of the oxidizing property of the catalysts has been proposed. A weak mixture allows to be near the conditions of the catalyzed filter and the impact of the physical properties of the material in the soot combustion is then measured. (O.M.)

  8. Étude économique des foyers domestiques par la technique d ...

    African Journals Online (AJOL)

    Les foyers font partie de la vie courante. Chaque ménage en utilise pour la cuisson de ses repas. Dans les pays en développement, la plupart des populations utilisent surtout des foyers à combustibles ligneux. Les effets négatifs sur l'environnement sont aujourd'hui bien connus : poches de désertification, érosion des sols, ...

  9. Désulfuration : avant, pendant ou après la combustion ? Synthèse bibliographique Desulfurization: Before, During Or After Combustion? Bibliographic Synthesis

    Directory of Open Access Journals (Sweden)

    Benchecroun N.

    2006-11-01

    Full Text Available Les perspectives d'applications de nouvelles normes aux émissions des grandes installations de combustion, tant aux Etats-Unis qu'en Europe de l'Ouest ont suscité de nombreuses recherches. Les diverses publications qui leur sont consacrées traitent le plus souvent de la combustion de charbons et, beaucoup plus rarement, de l'adaptabilité de ces procédés à des combustibles liquides ou de techniques spécifiques. Les principaux points technico-économiques qui se dégagent sur la désulfuration des combustibles liquides sont donnés dans cet article. Enfin, au-delà des aspects techniques, on notera que la désulfuration des combustibles liquides, et plus particulièrement du fuel lourd, est liée à deux aspects plus politiques : - l'application de normes sur les émissions des installations de combustion (ou les dérogations possibles qui concernent non seulement les oxydes de soufre mais aussi les oxydes d'azote et les particules contenues dans les fumées; - l'avenir des fuels lourds tant sur le plan quantitatif (marché que qualitatif (constitution du pool fuel et spécifîcations. The prospects that new emission standards will be applied to large combustion installations, both in the United States and Western Europe, have given rise to extensive research. The different publications devoted to this research usually deal with coal combustion and more rarely with the suitability of such processes for liquid fuels or specific techniques. The leading technico-economic points involved in the desulfurization of liquid fuels are given in this article. Likewise, over and beyond the technical aspects, it can be seen that the desulfurization of liquid fuels, and more particularly of heavy fuel oil, is linked to two more politicalaspects:(a the application of standards on emissions from combustion installations (or possible derogations concerning not only sulfur oxides but also nitrogen oxides and particles contained in fumes;(b the future of

  10. Les impacts des énergies fossiles sur l'environnement

    OpenAIRE

    Landrieu , Guy

    1994-01-01

    La satisfaction de leurs besoins en énergie est l'un des principaux facteurs de la transformation de leur environnement par les sociétés industrielles. Les combustibles carbonés fossiles, qui représentent environ 90% de la production commerciale d'énergie dans le monde, ont un rôle important dans ce processus de transformation. Une première donnée qui explique l'ampleur des impacts sur l'environnement liés aux combustibles fossiles est l'importance des flux de matières en circulation. On extr...

  11. Strobes: An oscillatory combustion

    NARCIS (Netherlands)

    Corbel, J.M.L.; Lingen, J.N.J. van; Zevenbergen, J.F.; Gijzeman, O.L.J.; Meijerink, A.

    2012-01-01

    Strobe compositions belong to the class of solid combustions. They are mixtures of powdered ingredients. When ignited, the combustion front evolves in an oscillatory fashion, and flashes of light are produced by intermittence. They have fascinated many scientists since their discovery at the

  12. Catalytically enhanced combustion process

    International Nuclear Information System (INIS)

    Rodriguez, C.

    1992-01-01

    This patent describes a fuel having improved combustion efficiency. It comprises a petroleum based liquid hydrocarbon; and a combustion catalyst comprising from about 18 to about 21 weight percent naphthalene, from about 75 to about 80 weight percent toluene, and from about 2.8 to about 3.2 weight percent benzyl alcohol

  13. Strobes: An Oscillatory Combustion

    NARCIS (Netherlands)

    Corbel, J.M.L.; van Lingen, J.N.J.; Zevenbergen, J.F.; Gijzeman, O.L.J.; Meijerink, A.

    2012-01-01

    Strobe compositions belong to the class of solid combustions. They are mixtures of powdered ingredients. When ignited, the combustion front evolves in an oscillatory fashion, and flashes of light are produced by intermittence. They have fascinated many scientists since their discovery at the

  14. Fifteenth combustion research conference

    International Nuclear Information System (INIS)

    1993-01-01

    The BES research efforts cover chemical reaction theory, experimental dynamics and spectroscopy, thermodynamics of combustion intermediates, chemical kinetics, reaction mechanisms, combustion diagnostics, and fluid dynamics and chemically reacting flows. 98 papers and abstracts are included. Separate abstracts were prepared for the papers

  15. Fifteenth combustion research conference

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1993-06-01

    The BES research efforts cover chemical reaction theory, experimental dynamics and spectroscopy, thermodynamics of combustion intermediates, chemical kinetics, reaction mechanisms, combustion diagnostics, and fluid dynamics and chemically reacting flows. 98 papers and abstracts are included. Separate abstracts were prepared for the papers.

  16. Fuels and Combustion

    KAUST Repository

    Johansson, Bengt

    2016-08-17

    This chapter discusses the combustion processes and the link to the fuel properties that are suitable for them. It describes the basic three concepts, including spark ignition (SI) and compression ignition (CI), and homogeneous charge compression ignition (HCCI). The fuel used in a CI engine is vastly different from that in an SI engine. In an SI engine, the fuel should sustain high pressure and temperature without autoignition. Apart from the dominating SI and CI engines, it is also possible to operate with a type of combustion: autoignition. With HCCI, the fuel and air are fully premixed before combustion as in the SI engine, but combustion is started by the increased pressure and temperature during the compression stroke. Apart from the three combustion processes, there are also a few combined or intermediate concepts, such as Spark-Assisted Compression Ignition (SACI). Those concepts are discussed in terms of the requirements of fuel properties.

  17. PDF Modeling of Turbulent Combustion

    National Research Council Canada - National Science Library

    Pope, Stephen B

    2006-01-01

    .... The PDF approach to turbulent combustion has the advantages of fully representing the turbulent fluctuations of species and temperature, and of allowing realistic combustion chemistry to be implemented...

  18. Modélisation de la combustion dans un moteur diesel d'automobile

    Science.gov (United States)

    Pinchon, Philippe

    La plupart des moteurs diesels utilisés pour la traction des véhicules automobiles sont des moteurs à préchambre. Le combustible y est introduit sous forme liquide, à haute pression, se vaporise, auto-inflamme et brûle dans un espace confiné dans lequel règnent des vitesses d'écoulement très élevées. La vitesse de combustion, et donc le rendement du moteur, sont très sensibles à divers paramètres liés à l'injection ou à la géométrie de la chambre. Cette dernière joue un rôle prédominant sur l'aérodynamique interne et son interaction avec la propagation de la flamme.

  19. Development and validation of an Eulerian model towards the simulation of fuel injection in internal combustion engines; Developpement et validation d'un modele eulerien en vue de la simulation des jets de carburants dans les moteurs a combustion interne

    Energy Technology Data Exchange (ETDEWEB)

    Truchot, B.

    2005-12-15

    The objective of this work is to develop an Eulerian two phase model to improve the prediction of fuel injection in internal combustion engines, particularly the dense liquid zone close to the nozzle. Lagrangian models, usually used in engine simulations, are based on the assumption of dispersed two phase flows with low liquid volume fraction, which is not fulfilled in the case of direct injection engine technology. Different Eulerian approaches are available in the literature. Physical phenomena that occur near the nozzle and characteristics of each model lead to the choice of a two fluids two pressures model. Several open terms appear in the equations of the model: exchange between the two phases and turbulent correlations. Closures of exchange terms are based on the spherical droplets hypothesis while a RANS approach is adopted to close turbulent correlations. This model has been integrated in the IFP CFD code, IFP-C3D. Several numerical tests and analytical validations (for single and two phase flows) have been then carried out in order to check the correct implementation of equations and the predictivity of the model and closures. Modifications in the turbulent model of the gas have required validations in both the gas phase (flow behind a sudden enlargement) and the liquid phase (pure liquid injection). A two phase mixing layer has been then used to validate the whole model. Finally, injection tests have been achieved under realistic conditions (similar to those encountered in automotive engines) in order to check the feasibility of engine computations using the developed Eulerian approach. These tests have also allowed to check the compatibility of this approach with the specificities of engine simulations (especially mesh movement). (author)

  20. Dry low combustion system with means for eliminating combustion noise

    Science.gov (United States)

    Verdouw, Albert J.; Smith, Duane; McCormick, Keith; Razdan, Mohan K.

    2004-02-17

    A combustion system including a plurality of axially staged tubular premixers to control emissions and minimize combustion noise. The combustion system includes a radial inflow premixer that delivers the combustion mixture across a contoured dome into the combustion chamber. The axially staged premixers having a twist mixing apparatus to rotate the fluid flow and cause improved mixing without causing flow recirculation that could lead to pre-ignition or flashback.

  1. Sandia Combustion Research: Technical review

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-07-01

    This report contains reports from research programs conducted at the Sandia Combustion Research Facility. Research is presented under the following topics: laser based diagnostics; combustion chemistry; reacting flow; combustion in engines and commercial burners; coal combustion; and industrial processing. Individual projects were processed separately for entry onto the DOE databases.

  2. Multi-Dimensional Modeling of the Aerodynamic and Combustion in Diesel Engines Modélisation multidimensionnelle de l'aérodynamique et de la combustion dans les moteurs diesel

    Directory of Open Access Journals (Sweden)

    Delhaye B.

    2006-12-01

    Full Text Available The purpose of this paper is to present an overview of Computational Fluid Dynamics (CFD and combustion simulation applications to automotive power train development, and the methodologies we developed at PSA to integrate numerical simulation into the development process. We illustrate these methodologies with some applications concerning the development of PSA HDI engines. Dans cet article, on présente un panorama des applications de la mécanique des fluides numérique et de la simulation de la combustion pour le développement des groupes motopropulseurs, ainsi que les méthodologies que nous avons conçues au sein du groupe PSA pour intégrer la simulation numérique dans ce processus de développement. Nous illustrons cette démarche par des exemples d'applications issues du développement des moteurs HDI injection directe common rail de PSA.

  3. Indoor combustion and asthma.

    Science.gov (United States)

    Belanger, Kathleen; Triche, Elizabeth W

    2008-08-01

    Indoor combustion produces both gases (eg, nitrogen dioxide, carbon monoxide) and particulate matter that may affect the development or exacerbation of asthma. Sources in the home include both heating devices (eg, fireplaces, woodstoves, kerosene heaters, flued [ie, vented] or nonflued gas heaters) and gas stoves for cooking. This article highlights the recent literature examining associations between exposure to indoor combustion and asthma development and severity. Since asthma is a chronic condition affecting both children and adults, both age groups are included in this article. Overall, there is some evidence of an association between exposure to indoor combustion and asthma, particularly asthma symptoms in children. Some sources of combustion such as coal stoves have been more consistently associated with these outcomes than other sources such as woodstoves.

  4. Des Connaissances Aux Politiques

    International Development Research Centre (IDRC) Digital Library (Canada)

    Dans beaucoup de pays en développement, la faible capacité du gouvernement est pratiquement la définition des problèmes de développement du pays. ...... Promouvoir l'échange des connaissances émanant des recherches ainsi que des outils et des résultats, et le dialogue entre les pays, institutions et donateurs.

  5. Sandia Combustion Research Program

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, S.C.; Palmer, R.E.; Montana, C.A. (eds.)

    1988-01-01

    During the late 1970s, in response to a national energy crisis, Sandia proposed to the US Department of Energy (DOE) a new, ambitious program in combustion research. Shortly thereafter, the Combustion Research Facility (CRF) was established at Sandia's Livermore location. Designated a ''user facility,'' the charter of the CRF was to develop and maintain special-purpose resources to support a nationwide initiative-involving US inventories, industry, and national laboratories--to improve our understanding and control of combustion. This report includes descriptions several research projects which have been simulated by working groups and involve the on-site participation of industry scientists. DOE's Industry Technology Fellowship program, supported through the Office of Energy Research, has been instrumental in the success of some of these joint efforts. The remainder of this report presents results of calendar year 1988, separated thematically into eleven categories. Referred journal articles appearing in print during 1988 and selected other publications are included at the end of Section 11. Our traditional'' research activities--combustion chemistry, reacting flows, diagnostics, engine and coal combustion--have been supplemented by a new effort aimed at understanding combustion-related issues in the management of toxic and hazardous materials.

  6. Variabilite des productions et des revenus des exploitations ...

    African Journals Online (AJOL)

    ... sont à dominance céréale et coton avec environ 75 % des assolements. Les revenus nets des EAF montrent en moyenne une prédominance des productions végétales (1 394 976 Fcfa) et animales, (1 420 430 Fcfa) sur les activités de diversification (358 449 Fcfa). Mots clés : production, revenu, économie, performance, ...

  7. Modelisation des effets physico-techniques pour la conception des ...

    African Journals Online (AJOL)

    automatisation dans les installations industrielles a besoin d'une régulation automatique des commandes des processus technologiques pour lesquelles certaines contraintes sont à relever compte tenu des exigences des innovations scientifiques de ...

  8. Combustion behavior of spent solvent in a submerged combustion process

    International Nuclear Information System (INIS)

    Uchiyama, Gunzo; Maeda, Mitsuru; Fujine, Sachio; Amakawa, Masayuki; Uchida, Katsuhide.

    1993-10-01

    An experimental study has been conducted in order to evaluate the applicability of a submerged combustion technique to the treatment of spent solvents contaminated with TRU elements. A bench-scale equipment of submerged combustor having combustion capacity of 1.39 liter of tri-n-butyl phosphate (TBP) per hour was used to obtain process data such as the distribution behavior of radioactive nuclides in the submerged combustion process. This report describes the experimental results on the combustion characteristics of the simulated spent solvents of TBP and/or n-dodecane, and on the distribution behaviors of combustion products such as ruthenium and iodine in the submerged combustion process. (author)

  9. Study of atmospheric emissions from liquid and solid fuels burning facilities and from raw phosphate chemical treatment in Sfax City (Tunisia); Etude des residus de combustion des fuels liquide et solide et de traitement chimique du phosphate brut dans la ville de Sfax (Tunisie)

    Energy Technology Data Exchange (ETDEWEB)

    Azri, Ch; Tili, A.; Serbaji, M.M. [Faculte des Sciences de Sfax, Dept. des Sciences de la Terre, Sfax (Tunisia); Medhioub, K. [Institut Preparatoire aux Etudes d' Ingenieurs de Sfax (IPEIS), Sfax (Tunisia)

    2002-07-01

    Study of atmospheric emissions from solid and liquid fuels burning facilities and from chemical treatment processes of raw phosphate in Sfax City (Tunisia) shows different forms of pollution concerning mainly sulfur oxides (SO{sub x}), sulfuric and phosphoric acid mists, fluorinated compounds and dust. Limited performances of amortized and/or over used de-pollution systems can explain high atmospheric emissions above emission limits. Gaseous pollution has been shown as coming mainly from phosphate treatment processes inside the chemical complex 'SIAPE' while particulate pollution is coming from all specific industries (SIAPE, charcoal facilities and weaving and soap factories). Calculated emission factors of these industries for some heavy metals (Pb, Cd, Ni, Cu, Zn) are very different. They are ranging from 0.3 to 9.5 g/t for phosphate treatment residues. Excepted Ni with 15.5 g/t, they are rather small for heavy fuels combustion residues. It, nevertheless, exceeds the emission factor of Ni for the phosphate treatment process. Volumes of emissions and calculated annual fluxes of metals are showing that 'SIAPE' could be a potential source of atmospheric pollution in the city. Its contribution to metal emissions is really exceeding emissions from well identified heavy fuels burning facilities in the city. Just to compare, Ni emissions from its processes are equal to emissions from 38 heavy fuels burning facilities of 4.8 t/day capacity (Ni 1 046 kg/year instead of 27 kg/year). Such a fact is clearly pointing out the high level of anthropogenic pollution from chemical processes adopted for primary matter transformation. They hence should be fitted with suitable de-pollution systems. (authors)

  10. variabilite des productions et des revenus des exploitations

    African Journals Online (AJOL)

    3Centre de coopération internationale en recherche agronomique pour le développement (CIRAD), UMR Innovation,. Montpellier, France. Doubangolo COULIBALY, Email kone_b@yahoo.fr. RESUME. La durabilité des systèmes de production à base de coton dans un contexte de variabilité des prix aux producteurs et de ...

  11. La metamorphose des cypris femelles des Rhizocephales

    NARCIS (Netherlands)

    Veillet, A.

    1964-01-01

    Depuis la découverte de la métamorphose des cypris de Sacculina carcini Thompson par Delage, peu de biologistes se sont intéressés au développement des Rhizocéphales. On admet aujourd'hui que tous les Cirripèdes parasites ont, comme Sacculina carcini, une forme kentrogone qui inocule le parasite au

  12. Combustion and regulation; Combustion et reglementation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    This conference was organized after the publication of the French by-law no 2010 relative to combustion installations and to the abatement of atmospheric pollution. Five topics were discussed during the conference: the new regulations, their content, innovations and modalities of application; the means of energy suppliers to face the new provisions and their schedule; the manufacturers proposals for existing installations and the new equipments; the administration control; and the impact of the new measures on exploitation and engineering. Twenty papers and 2 journal articles are reported in these proceedings. (J.S.)

  13. Internal combustion engine

    Science.gov (United States)

    Baker, Quentin A.; Mecredy, Henry E.; O'Neal, Glenn B.

    1991-01-01

    An improved engine is provided that more efficiently consumes difficult fuels such as coal slurries or powdered coal. The engine includes a precombustion chamber having a portion thereof formed by an ignition plug. The precombustion chamber is arranged so that when the piston is proximate the head, the precombustion chamber is sealed from the main cylinder or the main combustion chamber and when the piston is remote from the head, the precombustion chamber and main combustion chamber are in communication. The time for burning of fuel in the precombustion chamber can be regulated by the distance required to move the piston from the top dead center position to the position wherein the precombustion chamber and main combustion chamber are in communication.

  14. Transition nozzle combustion system

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Won-Wook; McMahan, Kevin Weston; Maldonado, Jaime Javier

    2016-11-29

    The present application provides a combustion system for use with a cooling flow. The combustion system may include a head end, an aft end, a transition nozzle extending from the head end to the aft end, and an impingement sleeve surrounding the transition nozzle. The impingement sleeve may define a first cavity in communication with the head end for a first portion of the cooling flow and a second cavity in communication with the aft end for a second portion of the cooling flow. The transition nozzle may include a number of cooling holes thereon in communication with the second portion of the cooling flow.

  15. Studies in combustion dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Koszykowski, M.L. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    The goal of this program is to develop a fundamental understanding and a quantitative predictive capability in combustion modeling. A large part of the understanding of the chemistry of combustion processes comes from {open_quotes}chemical kinetic modeling.{close_quotes} However, successful modeling is not an isolated activity. It necessarily involves the integration of methods and results from several diverse disciplines and activities including theoretical chemistry, elementary reaction kinetics, fluid mechanics and computational science. Recently the authors have developed and utilized new tools for parallel processing to implement the first numerical model of a turbulent diffusion flame including a {open_quotes}full{close_quotes} chemical mechanism.

  16. Alcohol combustion chemistry

    KAUST Repository

    Sarathy, Mani

    2014-10-01

    Alternative transportation fuels, preferably from renewable sources, include alcohols with up to five or even more carbon atoms. They are considered promising because they can be derived from biological matter via established and new processes. In addition, many of their physical-chemical properties are compatible with the requirements of modern engines, which make them attractive either as replacements for fossil fuels or as fuel additives. Indeed, alcohol fuels have been used since the early years of automobile production, particularly in Brazil, where ethanol has a long history of use as an automobile fuel. Recently, increasing attention has been paid to the use of non-petroleum-based fuels made from biological sources, including alcohols (predominantly ethanol), as important liquid biofuels. Today, the ethanol fuel that is offered in the market is mainly made from sugar cane or corn. Its production as a first-generation biofuel, especially in North America, has been associated with publicly discussed drawbacks, such as reduction in the food supply, need for fertilization, extensive water usage, and other ecological concerns. More environmentally friendly processes are being considered to produce alcohols from inedible plants or plant parts on wasteland. While biofuel production and its use (especially ethanol and biodiesel) in internal combustion engines have been the focus of several recent reviews, a dedicated overview and summary of research on alcohol combustion chemistry is still lacking. Besides ethanol, many linear and branched members of the alcohol family, from methanol to hexanols, have been studied, with a particular emphasis on butanols. These fuels and their combustion properties, including their ignition, flame propagation, and extinction characteristics, their pyrolysis and oxidation reactions, and their potential to produce pollutant emissions have been intensively investigated in dedicated experiments on the laboratory and the engine scale

  17. Combuster. [low nitrogen oxide formation

    Science.gov (United States)

    Mckay, R. A. (Inventor)

    1978-01-01

    A combuster is provided for utilizing a combustible mixture containing fuel and air, to heat a load fluid such as water or air, in a manner that minimizes the formation of nitrogen oxide. The combustible mixture passes through a small diameter tube where the mixture is heated to its combustion temperature, while the load fluid flows past the outside of the tube to receive heat. The tube is of a diameter small enough that the combustible mixture cannot form a flame, and yet is not subject to wall quench, so that combustion occurs, but at a temperature less than under free flame conditions. Most of the heat required for heating the combustible mixture to its combustion temperature, is obtained from heat flow through the walls of the pipe to the mixture.

  18. Toxicology of Biodiesel Combustion products

    Science.gov (United States)

    1. Introduction The toxicology of combusted biodiesel is an emerging field. Much of the current knowledge about biological responses and health effects stems from studies of exposures to other fuel sources (typically petroleum diesel, gasoline, and wood) incompletely combusted. ...

  19. Direction des Publications

    African Journals Online (AJOL)

    Synthese

    37. Taux des lipides et des protéines et composition en acides gras du tissu comestible des crustacés et des mollusques pêchés en Algérie : Effet du halofénozide (RH-0345) sur la composition en acides gras de. Penaeus kerathurus (Crustacé, Décapode). Samira Gheid. 1. , Safia Nadji. 2 et Mohamed El Hadi Khebbeb. 3.

  20. Methoden Des Fremdsprachenunterrichts

    Directory of Open Access Journals (Sweden)

    Rasa Sklizmantaitė

    2011-04-01

    Full Text Available Beim Unterrichten einer Fremdsprache ist es wichtig, Methoden des Fremdsprachenunterrichts zu kennen, um eine Methode des Unterrichts nach dem Niveau und Bedürfnissen der entsprechenden Gruppe opti-mal zu wählen. Im Artikel wird der Überblick des Fremdsprachenunterrichts im Hinblick auf historische Entwicklung dargeboten sowie die Hauptmerkmale einiger Methoden des Fremdsprachenunterrichts aufgezählt.

  1. Combustion Engine Identification and Control

    OpenAIRE

    Blasco Serrano, Daniel

    2013-01-01

    The topic of this thesis is system identification and control of two different internal combustion engines, Partially Premixed Combustion (PPC) engine and a more conventional Combustion Ignited (CI) diesel engine. The control of both engines is aimed to emission reduction and to increase the eficiency. There is an introduction to the internal combustion engine, as well as theory used about system identification and Model Predictive Control (MPC). A physical model of a PPC en...

  2. Sanitary effects of fossil fuels; Effets sanitaires des combustibles fossiles

    Energy Technology Data Exchange (ETDEWEB)

    Nifenecker, H. [Centre National de la Recherche Scientifique (IN2P3/CNRS), 38 - Grenoble (France)

    2006-07-01

    In this compilation are studied the sanitary effects of fossil fuels, behavioral and environmental sanitary risks. The risks in connection with the production, the transport and the distribution(casting) are also approached for the oil(petroleum), the gas and the coal. Accidents in the home are evoked. The risks due to the atmospheric pollution are seen through the components of the atmospheric pollution as well as the sanitary effects of this pollution. (N.C.)

  3. Des racines et des ailes

    Directory of Open Access Journals (Sweden)

    Stéphanie Vincent-Geslin

    2012-05-01

    Full Text Available Les mobilités pendulaires semblent être en augmentation en Europe depuis une dizaine d’années. Cette croissance du temps passé à se déplacer amène à remettre en question la conjecture de Zahavi et apparaît relativement inexplicable en regard du paradigme classique de l’acteur rationnel traditionnellement utilisé dans le champ des transports. Si, dans la littérature, les temps de déplacements sont principalement expliqués par le contexte résidentiel, la forme urbaine et le travail, ce cadre explicatif ne dit rien des processus de décision eux-mêmes qui amènent aux pendularités intensives.À partir d’une enquête qualitative menée auprès de pendulaires français, suisses et belges, cette contribution propose d’analyser les arbitrages et les éléments déterminants des processus de la grande pendularité. Les mobilités quotidiennes pendulaires apparaissent comme le résultat de compromis entre activité professionnelle, attachement résidentiel et choix de vie et prennent ainsi la forme de stratégies de conciliation entre vie privée et vie professionnelle. Ces mobilités spatiales permettent alors paradoxalement la préservation des ancrages résidentiels, sociaux et familiaux.Roots and wings. Long-distance commuting patterns, or how to conciliate professional and personal lifeLong-distance commuting patterns appear to be increasing in Europe over the last ten years. These raising mobility patterns lead to reappraise the Zahavi conjecture and appear largely inexplicable by the classical rational actor paradigm traditionally used in transportation research. In literature, commuting is mainly explained by residential contexts, urban forms and job. Nevertheless this theoretical frame says little about the decision-making processes themselves. Based on a qualitative survey conducted in three European countries - France, Belgium and Switzerland – among a population of high commuters, this paper proposes an analysis of

  4. Civili, langue des Baloango

    DEFF Research Database (Denmark)

    Mavoungou, Paul Achille; Ndinga-Koumba-Binza, Hugues Steve

    , Congo, Angola, etc.) issus de la décolonisation. Il présente de façon succincte quelques phénomènes historiques, phonologiques, morphosyntaxiques, homonymiques et analogiques de la langue. Des faits sémantiques des emprunts linguistiques y sont également décrits dans le cadre des changements...

  5. ANALYSE DES PERCEPTIONS LOCALES ET DES FACTEURS ...

    African Journals Online (AJOL)

    AISA

    haies vives) et la valorisation des produits forestiers tels que l'utilisation des tourteaux comme engrais organiques (Francis et al.,. 2005). Plusieurs études ont montré que les perceptions paysannes d'une technologie ou d'une innovation sont déterminantes pour son adoption. (Adesina et Baidu-forson, 1996). Les travaux.

  6. 75 FR 32142 - Combustible Dust

    Science.gov (United States)

    2010-06-07

    ... Combustible Dust AGENCY: Occupational Safety and Health Administration (OSHA), Labor. ACTION: Notice of combustible dust Web Chat. SUMMARY: OSHA invites interested parties to participate in a Web Chat on the workplace hazards of combustible dust. OSHA plans to use the information gathered in response to this Web...

  7. Optical Tomography in Combustion

    DEFF Research Database (Denmark)

    Evseev, Vadim

    . JQSRT 113 (2012) 2222, 10.1016/j.jqsrt.2012.07.015] included in the PhD thesis as an attachment. The knowledge and experience gained in the PhD project is the first important step towards introducing the advanced optical tomography methods of combustion diagnostics developed in the project to future...

  8. Sulfur Chemistry in Combustion I

    DEFF Research Database (Denmark)

    Johnsson, Jan Erik; Glarborg, Peter

    2000-01-01

    Most fossil fuels contain sulphur and also biofuels and household waste have a sulphur content. As a consequence sulphur species will often be present in combustion processes. In this paper the fate and influence of fuel sulphur species in combustion will be treated. First a description...... of the sulphur compounds in fossil fuels and the possibilities to remove them will be given. Then the combustion of sulphur species and their influence on the combustion chemistry and especially on the CO oxidation and the NOx formation will be described. Finally the in-situ removal of sulphur in the combustion...

  9. Low emission internal combustion engine

    Science.gov (United States)

    Karaba, Albert M.

    1979-01-01

    A low emission, internal combustion compression ignition engine having a cylinder, a piston movable in the cylinder and a pre-combustion chamber communicating with the cylinder near the top thereof and in which low emissions of NO.sub.x are achieved by constructing the pre-combustion chamber to have a volume of between 70% and 85% of the combined pre-chamber and main combustion chamber volume when the piston is at top dead center and by variably controlling the initiation of fuel injection into the pre-combustion chamber.

  10. Combustible caramel pour reacteurs de recherche: Experience acquise en fabrication, controles et irradiation du coeur d'osiris

    Science.gov (United States)

    de Contenson, Ghislain; Foulquier, Henri; Trotabas, Maria; Vignesoult, Nicole; Cerles, Jean-Marie; Delafosse, Jacques

    1982-04-01

    L'un des aboutissements des différentes actions menées en France concernant la conception, la fabrication et le développement des combustibles nucléaires a été la mise au point par le CEA d'un combustible de type plaque (combustible CARAMEL) susceptible d'être adapté a différentes catégories de réacteurs à eau (réacteur de puissance, propulsion navale, chauffage urbain, pile de recherche). Ces travaux ont été couronnés par la réalisation de tout un coeur et des recharges du réacteur de recherche à hautes performances, Osiris, à Saclay. L'ancien combustible en alliage U Al fortement enrichi a eté remplacé par un combustible caramel de faible enrichissement (7%), non proliférant. Ce nouveau coeur fonctionne avec satisfaction, depuis janvier 1980. Après une brève description des caractéristiques du combustible caramel et de ses principaux avantages, on présente sa fabrication ainsi que l'ensemble des contrôles de qualité auxquels il est soumis. Le programme de qualification ainsi que les principaux résultáts qui en ont été tirés sont exposés. On décrit également le programme de suivi du combustible en pile dont le but est de s'assurer du bon comportement du combustible sous irradiation. Le bon fonctionnement d'Osiris, qui a terminé 11 cycles d'irradiation le 21 avril 1981, a permis de montrer le bien fondé des choix effectués et l'excellent comportement de l'élément combustible dans les conditions pourtant sévères d'un réacteur de recherche à hautes performances.

  11. Appropriation des Tic et performance des entreprises

    OpenAIRE

    Lethiais , Virginie; Smati , Wided

    2009-01-01

    Quatre pages Marsouin; L'utilisation des TIC (Technologies de l'information et de la Communication) se développe dans les entreprises pour assurer des tâches de plus en plus nombreuses : la communication, la recherche d'informations, la commercialisation des produits et services, le travail en groupe, la gestion de l'entreprise, la prospection, etc. Les équipements en TIC ainsi que l'usage qui en est fait diffèrent d'une entreprise à une autre selon de nombreux critères. L'objet de ce quatre ...

  12. Study of the influence of combustion parameters on the formation of SO{sub 2}, NO and CO during the thermal degradation of phytosanitary products currently used in West Africa; Etude de l'influence des parametres de combustion sur la formation de SO{sub 2}, de NO et de CO lors de la degradation thermique de produits phytosanitaires d'usage courant en Afrique de l'Ouest

    Energy Technology Data Exchange (ETDEWEB)

    Bouda, M.; Segda, B.G.; Koulidiati, J. [Ouagadougou Univ., Ouagadougou (Burkina Faso). Laboratoire de physique et de chimie de l' environnement; Rogaume, T. [Poitiers a Niort Univ., Chasseneuil-du-Poitou (France). Ecole national superieure de mecanique et d' aerotechnique, Laboratoire de combustion et detonique; Sawadogo, P.W. [Inst. de l' environnement et de recherches agricoles, Ouagadougou (Burkina Faso). Laboratoire sol-eau-plante

    2008-05-15

    The challenge of treating soils in West Africa that have been contaminated with pesticides was discussed. Incineration is considered to be a viable method for the disposal of toxic industrial wastes, including phytosanitary products. The 2 main phytosanitary products currently used in West Africa are Cyperthion D and Cyperthion O. These 2 products were incinerated in a small-scale study in order to determine the influence of combustion parameters on the production of nitrogen monoxide (NO), carbon monoxide (CO), and sulphur dioxide (SO{sub 2}). The incineration process was optimized in order to reduce these emissions and other toxic gases. The study showed that there is a good correlation between the generation of these pollutants during the incineration of phytosanitary wastes and combustion parameters such as oxygen concentration, temperature, and residence time in the reactor core. Emissions of NO and SO{sub 2} decreased with an increase in residence time, but increased with higher local oxygen concentrations and higher combustion temperatures in the reactor core. CO emissions were found to increase with an increase in residence time, but decrease with higher temperatures and higher local oxygen concentrations. The results were used to pursue large-scale assays, in a rotatory incinerator, for the thermal processing of expired phytosanitary products. 22 refs., 2 tabs., 5 figs.

  13. Aerosols from biomass combustion

    Energy Technology Data Exchange (ETDEWEB)

    Nussbaumer, T.

    2001-07-01

    This report is the proceedings of a seminar on biomass combustion and aerosol production organised jointly by the International Energy Agency's (IEA) Task 32 on bio energy and the Swiss Federal Office of Energy (SFOE). This collection of 16 papers discusses the production of aerosols and fine particles by the burning of biomass and their effects. Expert knowledge on the environmental impact of aerosols, formation mechanisms, measurement technologies, methods of analysis and measures to be taken to reduce such emissions is presented. The seminar, visited by 50 participants from 11 countries, shows, according to the authors, that the reduction of aerosol emissions resulting from biomass combustion will remain a challenge for the future.

  14. Combustion engine system

    Science.gov (United States)

    Houseman, John (Inventor); Voecks, Gerald E. (Inventor)

    1986-01-01

    A flow through catalytic reactor which selectively catalytically decomposes methanol into a soot free hydrogen rich product gas utilizing engine exhaust at temperatures of 200 to 650 C to provide the heat for vaporizing and decomposing the methanol is described. The reactor is combined with either a spark ignited or compression ignited internal combustion engine or a gas turbine to provide a combustion engine system. The system may be fueled entirely by the hydrogen rich gas produced in the methanol decomposition reactor or the system may be operated on mixed fuels for transient power gain and for cold start of the engine system. The reactor includes a decomposition zone formed by a plurality of elongated cylinders which contain a body of vapor permeable, methanol decomposition catalyst preferably a shift catalyst such as copper-zinc.

  15. Dynamic features of combustion

    Science.gov (United States)

    Oppenheim, A. K.

    1985-01-01

    The dynamic features of combustion are discussed for four important cases: ignition, inflammation, explosion, and detonation. Ignition, the initiation of a self-sustained exothermic process, is considered in the simplest case of a closed thermodynamic system and its stochastic distribution. Inflammation, the initiation and propagation of self-sustained flames, is presented for turbulent flow. Explosion, the dynamic effects caused by the deposition of exothermic energy in a compressible medium, is illustrated by self-similar blast waves with energy deposition at the front and the adiabatic non-self-similar wave. Detonation, the most comprehensive illustration of all the dynamic effects of combustion, is discussed with a phenomenological account of the development and structure of the wave.

  16. Combustion science and engineering

    CERN Document Server

    Annamalai, Kalyan

    2006-01-01

    Introduction and Review of Thermodynamics Introduction Combustion Terminology Matter and Its Properties Microscopic Overview of Thermodynamics Conservation of Mass and Energy and the First Law of Thermodynamics The Second Law of Thermodynamics Summary Stoichiometry and Thermochemistry of Reacting Systems Introduction Overall Reactions Gas Analyses Global Conservation Equations for Reacting Systems Thermochemistry Summary Appendix Reaction Direction and Equilibrium Introduction Reaction Direction and Chemical Equilibrium Chemical Equilibrium Relations Vant Hoff Equation Adi

  17. Fluid-bed combustion

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, G.; Schoebotham, N.

    1981-02-01

    In Energy Equipment Company's two-stage fluidized bed system, partial combustion in a fluidized bed is followed by burn-off of the generated gases above the bed. The system can be retrofitted to existing boilers, and can burn small, high ash coal efficiently. It has advantages when used as a hot gas generator for process drying. Tests on a boiler at a Cadbury Schweppes plant are reported.

  18. Issues in waste combustion

    Energy Technology Data Exchange (ETDEWEB)

    Gustavsson, Lennart; Robertson, Kerstin; Tullin, Claes [Swedish National Testing and Research Inst., Boraas (Sweden); Sundquist, Lena; Wrangensten, Lars [AaF-Energikonsult AB, Stockholm (Sweden); Blom, Elisabet [AaF-Processdesign AB, Stockholm (Sweden)

    2003-05-01

    The main purpose of this review is to provide an overview of the state-of-the-art on research and development issues related to waste combustion with relevance for Swedish conditions. The review focuses on co-combustion in grate and fluidised bed furnaces. It is primarily literature searches in relevant databases of scientific publications with to material published after 1995. As a complement, findings published in different report series, have also been included. Since the area covered by this report is very wide, we do not claim to cover the issues included completely and it has not been possitile to evaluate the referred studies in depth. Basic knowledge about combustion issues is not included since such information can be found elsewhere in the literature. Rather, this review should be viewed as an overview of research and development in the waste-to-energy area and as such we hope that it will inspire scientists and others to further work in relevant areas.

  19. The Diesel Combustion Collaboratory: Combustion Researchers Collaborating over the Internet

    Energy Technology Data Exchange (ETDEWEB)

    C. M. Pancerella; L. A. Rahn; C. Yang

    2000-02-01

    The Diesel Combustion Collaborator (DCC) is a pilot project to develop and deploy collaborative technologies to combustion researchers distributed throughout the DOE national laboratories, academia, and industry. The result is a problem-solving environment for combustion research. Researchers collaborate over the Internet using DCC tools, which include: a distributed execution management system for running combustion models on widely distributed computers, including supercomputers; web-accessible data archiving capabilities for sharing graphical experimental or modeling data; electronic notebooks and shared workspaces for facilitating collaboration; visualization of combustion data; and video-conferencing and data-conferencing among researchers at remote sites. Security is a key aspect of the collaborative tools. In many cases, the authors have integrated these tools to allow data, including large combustion data sets, to flow seamlessly, for example, from modeling tools to data archives. In this paper the authors describe the work of a larger collaborative effort to design, implement and deploy the DCC.

  20. Internal combustion engine using premixed combustion of stratified charges

    Science.gov (United States)

    Marriott, Craig D [Rochester Hills, MI; Reitz, Rolf D [Madison, WI

    2003-12-30

    During a combustion cycle, a first stoichiometrically lean fuel charge is injected well prior to top dead center, preferably during the intake stroke. This first fuel charge is substantially mixed with the combustion chamber air during subsequent motion of the piston towards top dead center. A subsequent fuel charge is then injected prior to top dead center to create a stratified, locally richer mixture (but still leaner than stoichiometric) within the combustion chamber. The locally rich region within the combustion chamber has sufficient fuel density to autoignite, and its self-ignition serves to activate ignition for the lean mixture existing within the remainder of the combustion chamber. Because the mixture within the combustion chamber is overall premixed and relatively lean, NO.sub.x and soot production are significantly diminished.

  1. Development of flameless combustion; Desarrollo de la combustion sin flama

    Energy Technology Data Exchange (ETDEWEB)

    Flores Sauceda, M. Leonardo; Cervantes de Gortari, Jaime Gonzalo [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)]. E-mail: 8344afc@prodigy.net.mx; jgonzalo@servidor.unam.mx

    2010-11-15

    The paper intends contribute to global warming mitigation joint effort that develops technologies to capture the CO{sub 2} produced by fossil fuels combustion and to reduce emission of other greenhouse gases like the NO{sub x}. After reviewing existing combustion bibliography is pointed out that (a) touches only partial aspects of the collective system composed by Combustion-Heat transfer process-Environment, whose interactions are our primary interest and (b) most specialists think there is not yet a clearly winning technology for CO{sub 2} capture and storage. In this paper the study of combustion is focused as integrated in the aforementioned collective system where application of flameless combustion, using oxidant preheated in heat regenerators and fluent gas recirculation into combustion chamber plus appropriated heat and mass balances, simultaneously results in energy saving and environmental impact reduction. [Spanish] El trabajo pretende contribuir al esfuerzo conjunto de mitigacion del calentamiento global que aporta tecnologias para capturar el CO{sub 2} producido por la combustion de combustibles fosiles y para disminuir la emision de otros gases invernadero como NOx. De revision bibliografica sobre combustion se concluye que (a) trata aspectos parciales del sistema compuesto por combustion-proceso de trasferencia de calor-ambiente, cuyas interacciones son nuestro principal interes (b) la mayoria de especialistas considera no hay todavia una tecnologia claramente superior a las demas para captura y almacenaje de CO{sub 2}. Se estudia la combustion como parte integrante del mencionado sistema conjunto, donde la aplicacion de combustion sin flama, empleando oxidante precalentado mediante regeneradores de calor y recirculacion de gases efluentes ademas de los balances de masa y energia adecuados, permite tener simultaneamente ahorros energeticos e impacto ambiental reducido.

  2. Cartographie des directions dominantes des vents au Benin : Outil ...

    African Journals Online (AJOL)

    Cartographie des directions dominantes des vents au Benin : Outil de conception et de dimensionnement des ouvrages. ... nous avons, après la collecte des informations météorologiques, procédé : - à l'analyse des données (directions) des six stations météorologiques principales conformément aux méthodes statistiques.

  3. Propellant combustion at low pressures

    Energy Technology Data Exchange (ETDEWEB)

    Schoyer, H.F.R.; Korting, P.A.O.G.

    1986-03-01

    The combustion characteristics of a family of composite propellants have been investigated at low (i.e., subatmospheric) pressures and three different temperatures. Although a de Vieille-type burning rate law appeared to be applicable, the burning rate exponent and coefficient vary strongly with the initial temperatures. Indications are that this is primarily due to the presence of nitroguanidine and oxalate. Combustion efficiency proved to be poor. At low pressures, all propellants are susceptible to irregular burning: above 50 kPa oscillatory combustion was hardly observed. All propellants exhibit distinct preferred frequencies for oscillatory combustion. These frequencies, being much lower than the acoustic frequency of the test system, are associated with the combustion characteristics of the propellants. They depend strongly on the combustion pressure and the initial propellant temperature.

  4. Example Problems in LES Combustion

    Science.gov (United States)

    2016-09-26

    memorandum is the evaporation and subsequent combustion of liquid fuel droplets. Kerosene, a complex hydrogen mixture, is explored from the standpoint of...AFRL-RW-EG-TP-2016-002 Example Problems in LES Combustion Douglas V. Nance Air Force Research Laboratory Munitions...4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Example Problem in LES Combustion 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER

  5. Applications biotechnologiques des mycorhizes

    OpenAIRE

    Redecker, Dirk

    2012-01-01

    La symbiose mycorhizienne est une association entre un champignon mycorhizogène et une racine de plante-hôte. La mycorrhize à arbuscules (MA) est extrêmement ancienne puisqu’elle est datée de la même époque que l’apparition des plantes terrestres, il y a 460 millions d’années. Elle s’effectue entre un champignon mycorhizogène à arbuscules (CMA, phylum Glomeromycota) et plus de 80% des plantes terrestres. Les CMA sont des microorganismes ubiquitaires du sol et sont des biotrophes obligatoires ...

  6. Pulsating combustion - Combustion characteristics and reduction of emissions

    Energy Technology Data Exchange (ETDEWEB)

    Lindholm, Annika

    1999-11-01

    In the search for high efficiency combustion systems pulsating combustion has been identified as one of the technologies that potentially can meet the objectives of clean combustion and good fuel economy. Pulsating combustion offers low emissions of pollutants, high heat transfer and efficient combustion. Although it is an old technology, the interest in pulsating combustion has been renewed in recent years, due to its unique features. Various applications of pulsating combustion can be found, mainly as drying and heating devices, of which the latter also have had commercial success. It is, however, in the design process of a pulse combustor, difficult to predict the operating frequency, the heat release etc., due to the lack of a well founded theory of the phenomenon. Research concerning control over the combustion process is essential for developing high efficiency pulse combustors with low emissions. Natural gas fired Helmholtz type pulse combustors have been the experimental objects of this study. In order to investigate the interaction between the fluid dynamics and the chemistry in pulse combustors, laser based measuring techniques as well as other conventional measuring techniques have been used. The experimental results shows the possibilities to control the combustion characteristics of pulsating combustion. It is shown that the time scales in the large vortices created at the inlet to the combustion chamber are very important for the operation of the pulse combustor. By increasing/decreasing the time scale for the large scale mixing the timing of the heat release is changed and the operating characteristics of the pulse combustor changes. Three different means for NO{sub x} reduction in Helmholtz type pulse combustors have been investigated. These include exhaust gas recirculation, alteration of air/fuel ratio and changed inlet geometry in the combustion chamber. All used methods achieved less than 10 ppm NO{sub x} emitted (referred to stoichiometric

  7. The modes of gaseous combustion

    CERN Document Server

    Rubtsov, Nickolai M

    2016-01-01

    This book provides an analysis of contemporary problems in combustion science, namely flame propagation, detonation and heterophaseous combustion based on the works of the author. The current problems in the area of gas combustion, as well as the methods allowing to calculate and estimate limiting conditions of ignition, and flame propagation on the basis of experimental results are considered. The book focuses on the virtually inaccessible works of Russian authors and will be useful for experienced students and qualified scientists in the area of experimental studies of combustion processes.

  8. Mathematical Modeling in Combustion Science

    CERN Document Server

    Takeno, Tadao

    1988-01-01

    An important new area of current research in combustion science is reviewed in the contributions to this volume. The complicated phenomena of combustion, such as chemical reactions, heat and mass transfer, and gaseous flows, have so far been studied predominantly by experiment and by phenomenological approaches. But asymptotic analysis and other recent developments are rapidly changing this situation. The contributions in this volume are devoted to mathematical modeling in three areas: high Mach number combustion, complex chemistry and physics, and flame modeling in small scale turbulent flow combustion.

  9. Active Combustion Control Valve Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Over the past decade, research into active combustion control has yielded impressive results in suppressing thermoacoustic instabilities and widening the operational...

  10. Combustion from basics to applications

    CERN Document Server

    Lackner, Maximilian; Winter, Franz

    2013-01-01

    Combustion, the process of burning, is defined as a chemical reaction between a combustible reactant (the fuel) and an oxidizing agent (such as air) in order to produce heat and in most cases light while new chemical species (e.g., flue gas components) are formed. This book covers a gap on the market by providing a concise introduction to combustion. Most of the other books currently available are targeted towards the experienced users and contain too many details and/or contain knowledge at a fairly high level. This book provides a brief and clear overview of the combustion basics, suitable f

  11. Caracterisation environnementale des emissions atmospheriques d'une source fixe et creation d'un outil de gestion dynamique =

    Science.gov (United States)

    Fournier, Marie-Claude

    Une caracterisation des emissions atmospheriques provenant des sources fixes en operation, alimentees au gaz et a l'huile legere, a ete conduite aux installations visees des sites no.1 et no.2. La caracterisation et les calculs theoriques des emissions atmospheriques aux installations des sites no.1 et no.2 presentent des resultats qui sont en dessous des valeurs reglementaires pour des conditions d'operation normales en periode hivernale et par consequent, a de plus fortes demandes energetiques. Ainsi, pour une demande energetique plus basse, le taux de contaminants dans les emissions atmospheriques pourrait egalement etre en dessous des reglementations municipales et provinciales en vigueur. Dans la perspective d'une nouvelle reglementation provinciale, dont les termes sont discutes depuis 2005, il serait souhaitable que le proprietaire des infrastructures visees participe aux echanges avec le Ministere du Developpement Durable, de l'Environnement et des Parcs (MDDEP) du Quebec. En effet, meme si le principe de droit acquis permettrait d'eviter d'etre assujetti a la nouvelle reglementation, l'application de ce type de principe ne s'inscrit pas dans ceux d'un developpement durable. L'âge avance des installations etudiees implique la planification d'un entretien rigoureux afin d'assurer les conditions optimales de combustion en fonction du type de combustible. Des tests de combustion sur une base reguliere sont donc recommandes. Afin de supporter le processus de suivi et d'evaluation de la performance environnementale des sources fixes, un outil d'aide a la gestion de l'information environnementale a ete developpe. Dans ce contexte, la poursuite du developpement d'un outil d'aide a la gestion de l'information environnementale faciliterait non seulement le travail des personnes affectees aux inventaires annuels mais egalement le processus de communication entre les differents acteurs concernes tant intra- qu'inter-etablissement. Cet outil serait egalement un bon

  12. Combustion Byproducts Recycling Consortium

    Energy Technology Data Exchange (ETDEWEB)

    Ziemkiewicz, Paul; Vandivort, Tamara; Pflughoeft-Hassett, Debra; Chugh, Y Paul; Hower, James

    2008-08-31

    Each year, over 100 million tons of solid byproducts are produced by coal-burning electric utilities in the United States. Annual production of flue gas desulfurization (FGD) byproducts continues to increase as the result of more stringent sulfur emission restrictions. In addition, stricter limits on NOx emissions mandated by the 1990 Clean Air Act have resulted in utility burner/boiler modifications that frequently yield higher carbon concentrations in fly ash, which restricts the use of the ash as a cement replacement. Controlling ammonia in ash is also of concern. If newer, “clean coal” combustion and gasification technologies are adopted, their byproducts may also present a management challenge. The objective of the Combustion Byproducts Recycling Consortium (CBRC) is to develop and demonstrate technologies to address issues related to the recycling of byproducts associated with coal combustion processes. A goal of CBRC is that these technologies, by the year 2010, will lead to an overall ash utilization rate from the current 34% to 50% by such measures as increasing the current rate of FGD byproduct use and increasing in the number of uses considered “allowable” under state regulations. Another issue of interest to the CBRC would be to examine the environmental impact of both byproduct utilization and disposal. No byproduct utilization technology is likely to be adopted by industry unless it is more cost-effective than landfilling. Therefore, it is extremely important that the utility industry provide guidance to the R&D program. Government agencies and privatesector organizations that may be able to utilize these materials in the conduct of their missions should also provide input. The CBRC will serve as an effective vehicle for acquiring and maintaining guidance from these diverse organizations so that the proper balance in the R&D program is achieved.

  13. Objetivo: Ahorro de combustible

    OpenAIRE

    Cabrero Sopena, Rosa María; Catalán Mogorrón, Heliodoro Fco.

    2011-01-01

    Con los precios de la energía en escalada imparable y particularmente, el gasóleo en precios históricos, se hace indispensable que el agricultor intente ahorrar en la partida energética de su explotación agrícola. El tractor se pondrá en el punto de mira del ahorro. Curioso paradigma, el gran amigo del agricultor, el tractor, se convierte en el máximo responsable de la partida energética. Una cifra, el consumo de combustible puede llegar incluso al 50% del coste horario total en la vida de...

  14. Alternate fuels; Combustibles alternos

    Energy Technology Data Exchange (ETDEWEB)

    Romero Paredes R, Hernando; Ambriz G, Juan Jose [Universidad Autonoma Metropolitana. Iztapalapa (Mexico)

    2003-07-01

    In the definition and description of alternate fuels we must center ourselves in those technological alternatives that allow to obtain compounds that differ from the traditional ones, in their forms to be obtained. In this article it is tried to give an overview of alternate fuels to the conventional derivatives of petroleum and that allow to have a clear idea on the tendencies of modern investigation and the technological developments that can be implemented in the short term. It is not pretended to include all the tendencies and developments of the present world, but those that can hit in a relatively short term, in accordance with agreed with the average life of conventional fuels. Nevertheless, most of the conversion principles are applicable to the spectrum of carbonaceous or cellulosic materials which are in nature, are cultivated or wastes of organic origin. Thus one will approach them in a successive way, the physical, chemical and biological conversions that can take place in a production process of an alternate fuel or the same direct use of the fuel such as burning the sweepings derived from the forests. [Spanish] En la definicion y descripcion de combustibles alternos nos debemos centrar en aquellas alternativas tecnologicas que permitan obtener compuestos que difieren de los tradicionales, al menos en sus formas de ser obtenidos. En este articulo se pretende dar un panorama de los combustibles alternos a los convencionales derivados del petroleo y que permita tener una idea clara sobre las tendencias de la investigacion moderna y los desarrollos tecnologicos que puedan ser implementados en el corto plazo. No se pretende abarcar todas las tendencias y desarrollos del mundo actual, sino aquellas que pueden impactar en un plazo relativamente corto, acordes con la vida media de los combustibles convencionales. Sin embargo, la mayor parte de los principios de conversion son aplicables al espectro de materiales carbonaceos o celulosicos los cuales se

  15. Combustion Stratification for Naphtha from CI Combustion to PPC

    KAUST Repository

    Vallinayagam, R.

    2017-03-28

    This study demonstrates the combustion stratification from conventional compression ignition (CI) combustion to partially premixed combustion (PPC). Experiments are performed in an optical CI engine at a speed of 1200 rpm for diesel and naphtha (RON = 46). The motored pressure at TDC is maintained at 35 bar and fuelMEP is kept constant at 5.1 bar to account for the difference in fuel properties between naphtha and diesel. Single injection strategy is employed and the fuel is injected at a pressure of 800 bar. Photron FASTCAM SA4 that captures in-cylinder combustion at the rate of 10000 frames per second is employed. The captured high speed video is processed to study the combustion homogeneity based on an algorithm reported in previous studies. Starting from late fuel injection timings, combustion stratification is investigated by advancing the fuel injection timings. For late start of injection (SOI), a direct link between SOI and combustion phasing is noticed. At early SOI, combustion phasing depends on both intake air temperature and SOI. In order to match the combustion phasing (CA50) of diesel, the intake air temperature is increased to 90°C for naphtha. The combustion stratification from CI to PPC is also investigated for various level of dilution by displacing oxygen with nitrogen in the intake. The start of combustion (SOC) was delayed with the increase in dilution and to compensate for this, the intake air temperature is increased. The mixture homogeneity is enhanced for higher dilution due to longer ignition delay. The results show that high speed image is initially blue and then turned yellow, indicating soot formation and oxidation. The luminosity of combustion images decreases with early SOI and increased dilution. The images are processed to generate the level of stratification based on the image intensity. The level of stratification is same for diesel and naphtha at various SOI. When O concentration in the intake is decreased to 17.7% and 14

  16. Some Factors Affecting Combustion in an Internal-Combustion Engine

    Science.gov (United States)

    Rothrock, A M; Cohn, Mildred

    1936-01-01

    An investigation of the combustion of gasoline, safety, and diesel fuels was made in the NACA combustion apparatus under conditions of temperature that permitted ignition by spark with direct fuel injection, in spite of the compression ratio of 12.7 employed. The influence of such variables as injection advance angle, jacket temperature, engine speed, and spark position was studied. The most pronounced effect was that an increase in the injection advance angle (beyond a certain minimum value) caused a decrease in the extent and rate of combustion. In almost all cases combustion improved with increased temperature. The results show that at low air temperatures the rates of combustion vary with the volatility of the fuel, but that at high temperatures this relationship does not exist and the rates depend to a greater extent on the chemical nature of the fuel.

  17. Preliminary assessment of combustion modes for internal combustion wave rotors

    Science.gov (United States)

    Nalim, M. Razi

    1995-01-01

    Combustion within the channels of a wave rotor is examined as a means of obtaining pressure gain during heat addition in a gas turbine engine. Several modes of combustion are considered and the factors that determine the applicability of three modes are evaluated in detail; premixed autoignition/detonation, premixed deflagration, and non-premixed compression ignition. The last two will require strong turbulence for completion of combustion in a reasonable time in the wave rotor. The compression/autoignition modes will require inlet temperatures in excess of 1500 R for reliable ignition with most hydrocarbon fuels; otherwise, a supplementary ignition method must be provided. Examples of combustion mode selection are presented for two core engine applications that had been previously designed with equivalent 4-port wave rotor topping cycles using external combustion.

  18. Rhéologie et combustion de mélanges charbon-eau Rheology and Combustion of Coal-Water Mixtures

    Directory of Open Access Journals (Sweden)

    Durand J. P.

    2006-11-01

    Full Text Available Différents mélanges charbon-eau ont été préparés avec le charbon Freyming. Ces mélanges diffèrent par leurs teneurs en charbon, la distribution de taille de particules de charbon , la nature des agents dispersants. L'influence de la viscosité et de la coupe granulométrique initiale du charbon vis-à-vis de leur aptitude à la combustion a été déterminée. On observe que le rendement de combustion diminue au-delà d'une certaine teneur en particules micronisées dans le mélange, et qu'il n'existe pas de relation entre la viscosité et la combustibilité. D'autre part, l'ensemble des mélanges analysés présente un caractère newtonien jusqu'à des valeurs de taux de cisaillement très élevées de 20 000 s-1. Effects of viscosity and particle size distribution on combustibility were measured for slurries made from French bituminous coal with different dispersing agents, coal particle size distributions, and grindings methods. Combustion efficiency decreased beyond a certain level of fines in the mixture, while no relationship was observed between viscosity and combustibility. On the other hand, all of the mixtures tested have a Newtonian character, even at high shear rates up to 20 000 s-1.

  19. 3d Modeling of Combustion for Di-Si Engines Modélisation 3D de la combustion dans les moteurs à injection directe d'essence

    Directory of Open Access Journals (Sweden)

    Duclos J. P.

    2006-12-01

    Full Text Available Direct injection of gasoline is a promising concept to reduce fuel consumption of SI engines. The development of GDI engines is difficult and 3D CFD is a way to support its design. It requires models able to describe the spray and its evaporation and combustion. This paper presents a model, the ECFM, that enables to compute combustion for stratified load in the GDI engines. This model is a development of the Coherent Flame Model which includes thermal expansion effects, and is coupled with a burnt/unburnt gases conditionnal thermodynamic properties description. The model is validated by comparing measurements and computations on the GDI Mitsubishi engine in production. L'injection directe d'essence (IDE est un concept prometteur pour les moteurs à allumage commandé. La mise au point de ce type de moteur est néanmoins délicate, et le calcul 3D des chambres de combustion est un moyen d'aider à leur conception. Ceci nécessite cependant de disposer de modèles adaptés, à même de décrire le jet d'essence, son évaporation et la combustion du mélange créé. Cet article présente un modèle ECFM de simulation de la combustion dans les moteurs IDE, y compris en fonctionnement stratifié. C'est un développement du modèle flamme cohérente qui comprend des effets d'expansion thermique et est couplé avec une description conditionnelle gaz frais/gaz brûlés des grandeurs thermodynamiques. Ce modèle a été validé par rapprochement de mesures et simulations sur le moteur GDI Mitsubishi.

  20. Path planning during combustion mode switch

    Science.gov (United States)

    Jiang, Li; Ravi, Nikhil

    2015-12-29

    Systems and methods are provided for transitioning between a first combustion mode and a second combustion mode in an internal combustion engine. A current operating point of the engine is identified and a target operating point for the internal combustion engine in the second combustion mode is also determined. A predefined optimized transition operating point is selected from memory. While operating in the first combustion mode, one or more engine actuator settings are adjusted to cause the operating point of the internal combustion engine to approach the selected optimized transition operating point. When the engine is operating at the selected optimized transition operating point, the combustion mode is switched from the first combustion mode to the second combustion mode. While operating in the second combustion mode, one or more engine actuator settings are adjusted to cause the operating point of the internal combustion to approach the target operating point.

  1. Plasma igniter for internal-combustion engines

    Science.gov (United States)

    Breshears, R. R.; Fitzgerald, D. J.

    1978-01-01

    Hot ionized gas (plasma) ignites air/fuel mixture in internal combustion engines more effectively than spark. Electromagnetic forces propel plasma into combustion zone. Combustion rate is not limited by flame-front speed.

  2. Gestion des risques

    CERN Document Server

    Louisot, Jean-Paul

    2009-01-01

    Depuis le début du lie siècle, la gestion des risques connaît une véritable révolution culturelle. Jusqu'alors fonction technique, centrée autour de l'achat de couverture d'assurances, elle est devenue une discipline managériale et transversale : une valise d'instruments que chaque manager doit connaître et appliquer quels que soient son domaine de compétence et ses missions au sein de l'organisation. En effet, la gestion des risques est une culture qui doit être assimilée par chacun des acteurs. C'est précisément l'ambition des 101 questions rassemblées dans cet ouvrage : apporter à chaque manager d'entreprise, de collectivité, d'établissement de santé..., des réponses claires au " pourquoi " et au " comment " : Comment identifier les risques ? Comment analyser les risques ? Quels sont les objectifs de la gestion des risques ? Une carte des risques pour quoi faire ? Pourquoi faut-il financer les risques ? Les entreprises ont-elles des responsabilités pénales ? En quoi consiste la gestion...

  3. 75 FR 3881 - Combustible Dust

    Science.gov (United States)

    2010-01-25

    ... Combustible Dust AGENCY: Occupational Safety and Health Administration (OSHA), Labor. ACTION: Notice of stakeholder meetings. SUMMARY: OSHA invites interested parties to participate in informal stakeholder meetings on the workplace hazards of combustible dust. OSHA plans to use the information gathered at these...

  4. 75 FR 10739 - Combustible Dust

    Science.gov (United States)

    2010-03-09

    ... Combustible Dust AGENCY: Occupational Safety and Health Administration (OSHA), Labor. ACTION: Notice of stakeholder meetings. SUMMARY: OSHA invites interested parties to participate in informal stakeholder meetings on the workplace hazards of combustible dust. OSHA plans to use the information gathered at these...

  5. La gouvernance des risques naturels et la problematique des ...

    African Journals Online (AJOL)

    Depuis quelques années, la gouvernance des risques naturels dus aux inondations remet en cause les processus de mise en oeuvre des politiques urbaines et la qualité de la structure des aménagements dans les grandes villes du Golfe de Guinée. La perception de la gouvernance et l'application des politiques de ...

  6. Combustion & Laser Diagnostics Research Complex (CLDRC)

    Data.gov (United States)

    Federal Laboratory Consortium — Description: The Combustion and Laser Diagnostics Research Complex (CLRDC) supports the experimental and computational study of fundamental combustion phenomena to...

  7. Combustion instability control in the model of combustion chamber

    International Nuclear Information System (INIS)

    Akhmadullin, A N; Ahmethanov, E N; Iovleva, O V; Mitrofanov, G A

    2013-01-01

    An experimental study of the influence of external periodic perturbations on the instability of the combustion chamber in a pulsating combustion. As an external periodic disturbances were used sound waves emitted by the electrodynamics. The purpose of the study was to determine the possibility of using the method of external periodic perturbation to control the combustion instability. The study was conducted on a specially created model of the combustion chamber with a swirl burner in the frequency range from 100 to 1400 Hz. The study found that the method of external periodic perturbations may be used to control combustion instability. Depending on the frequency of the external periodic perturbation is observed as an increase and decrease in the amplitude of the oscillations in the combustion chamber. These effects are due to the mechanisms of synchronous and asynchronous action. External periodic disturbance generated in the path feeding the gaseous fuel, showing the high efficiency of the method of management in terms of energy costs. Power required to initiate periodic disturbances (50 W) is significantly smaller than the thermal capacity of the combustion chamber (100 kW)

  8. Photonique des Morphos

    CERN Document Server

    Berthier, Serge

    2010-01-01

    La photonique est déjà présente dans notre vie quotidienne, et on attend maintenant que la manipulation des photons permette aussi le traitement logique des informations. Cependant, l’élément de base qui permet cette manipulation de la lumière, le cristal photonique, est d’une réalisation complexe et mal contrôlée. Dans la course à la maîtrise de la lumière, les structures photoniques naturelles ont beaucoup à nous apprendre. C’est ce que nous montre Serge Berthier qui étudie dans ce livre la structure des écailles des Morphos. Tenant compte de l’essor récent des approches biomimétiques, il présente de manière détaillée plus de dix-huit techniques expérimentales utilisées pour ses analyses, ainsi que les diverses approches théoriques développées pour la modélisation de structures multi-échelles complexes. Première étude quasi-exhaustive des structures fines d’un genre et des propriétés optiques ainsi que colorimétriques générées, ce livre fournit aux entomologiste...

  9. Droit des organisations internationales

    CERN Document Server

    Sorel, Jean-Marc; Ndior, Valère

    2013-01-01

    Cet ouvrage collectif offre aux enseignants et chercheurs en droit international, aux praticiens et aux étudiants, une analyse actualisée du droit des organisations internationales. Il dresse en cinq parties un tableau, illustré par des exemples variés, des problématiques que soulève le phénomène polymorphe d institutionnalisation de la société internationale. La première partie est consacrée au phénomène des « organisations internationales », sous l angle à la fois de l institutionnalisation progressive des relations internationales et de la difficulté à cerner une catégorie unifiée. La deuxième partie rend compte de la création, de la disparition et des mutations des organisations internationales, ici envisagées comme systèmes institutionnels et ordres juridiques dérivés. La troisième partie analyse l autonomie que l acquisition de la personnalité juridique et de privilèges et immunités, un organe administratif intégré, un personnel ou un budget propres confèrent aux organi...

  10. Catalytic Combustion of Gasified Waste

    Energy Technology Data Exchange (ETDEWEB)

    Kusar, Henrik

    2003-09-01

    This thesis concerns catalytic combustion for gas turbine application using a low heating-value (LHV) gas, derived from gasified waste. The main research in catalytic combustion focuses on methane as fuel, but an increasing interest is directed towards catalytic combustion of LHV fuels. This thesis shows that it is possible to catalytically combust a LHV gas and to oxidize fuel-bound nitrogen (NH{sub 3}) directly into N{sub 2} without forming NO{sub x} The first part of the thesis gives a background to the system. It defines waste, shortly describes gasification and more thoroughly catalytic combustion. The second part of the present thesis, paper I, concerns the development and testing of potential catalysts for catalytic combustion of LHV gases. The objective of this work was to investigate the possibility to use a stable metal oxide instead of noble metals as ignition catalyst and at the same time reduce the formation of NO{sub x} In paper II pilot-scale tests were carried out to prove the potential of catalytic combustion using real gasified waste and to compare with the results obtained in laboratory scale using a synthetic gas simulating gasified waste. In paper III, selective catalytic oxidation for decreasing the NO{sub x} formation from fuel-bound nitrogen was examined using two different approaches: fuel-lean and fuel-rich conditions. Finally, the last part of the thesis deals with deactivation of catalysts. The various deactivation processes which may affect high-temperature catalytic combustion are reviewed in paper IV. In paper V the poisoning effect of low amounts of sulfur was studied; various metal oxides as well as supported palladium and platinum catalysts were used as catalysts for combustion of a synthetic gas. In conclusion, with the results obtained in this thesis it would be possible to compose a working catalytic system for gas turbine application using a LHV gas.

  11. Terminologie des indices boursiers

    OpenAIRE

    Van der Yeught, Michel

    2013-01-01

    Les indices boursiers sont omniprésents en anglais financier. Les plus importants sont universellement familiers mais leur nature et leur fonctionnement restent largement méconnus. Des distinctions (average/index, narrow index/broad index, price-weighted/market value-weighted, all share/ composite/ subindex) permettront à l’angliciste de spécialité d’adapter à chaque indice la terminologie française ou anglaise qui lui correspond. Des remarques sur des erreurs courantes, un mini-glossaire, un...

  12. Reducing emissions from diesel combustion

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This paper contains information dealing with engine design to reduce emissions and improve or maintain fuel economy. Topics include: Observation of High Pressure Fuel Spray with Laser Light Sheet Method; Determination of Engine Cylinder Pressures from Crankshaft Speed Fluctuations; Combustion Similarity for Different Size Diesel Engines: Theoretical Prediction and Experimental Results; Prediction of Diesel Engine Particulate Emission During Transient Cycles; Characteristics and Combustibility of Particulate Matter; Dual-Fuel Diesel Engine Using Butane; Measurement of Flame Temperature Distribution in D.I. Diesel Engine with High Pressure Fuel Injection: and Combustion in a Small DI Diesel Engine at Starting

  13. On Lean Turbulent Combustion Modeling

    Directory of Open Access Journals (Sweden)

    Constantin LEVENTIU

    2014-06-01

    Full Text Available This paper investigates a lean methane-air flame with different chemical reaction mechanisms, for laminar and turbulent combustion, approached as one and bi-dimensional problem. The numerical results obtained with Cantera and Ansys Fluent software are compared with experimental data obtained at CORIA Institute, France. First, for laminar combustion, the burn temperature is very well approximated for all chemical mechanisms, however major differences appear in the evaluation of the flame front thickness. Next, the analysis of turbulence-combustion interaction shows that the numerical predictions are suficiently accurate for small and moderate turbulence intensity.

  14. Study of the thermal drop at the uranium-can interface for fuel elements in gas-graphite reactors; Etude de la chute thermique au contact uranium-gaine pour des elements combustibles de reacteur de la filiere graphite-gaz

    Energy Technology Data Exchange (ETDEWEB)

    Faussat, A. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Levenes, G.; Michel, M. [Societe Industrielle de Combustible Nucleaire (France)

    1964-07-01

    The report reviews the tests now under way at the CEA, for determining the thermal contact resistance at the uranium-can interface for fuel elements used in gas-graphite type reactors. These are laboratory tests carried out with equipment based on the principle of a heat flow across a stack of test pieces having planar contact surfaces. The following points emerge from this work: - for a metallic uranium element canned in magnesium, of the type G-2 or EDF-2, a value of 0.2 deg C/W/cm{sup 2} seems reasonable for can temperatures of 400 deg C and above. - this value is independent of the micro-geometric state of the uranium surface in a range of roughness which easily includes those observed on tubes and rods produced industrially. - for the internal cans of elements cooled internally and externally, the value of the contact resistance for temperatures of under 400 deg C as a function of the stresses in the can has not yet been measured exactly. (authors) [French] Le rapport fait le point des essais actuellement en cours au CEA pour determiner la resistance thermique de contact uranium-gaine pour des reacteurs de la filiere graphite-gaz. Ces essais sont effectues en laboratoire sur des appareils bases sur le principe d'une circulation de flux de chaleur a travers un empilement d'eprouvettes dont les faces en contact sont planes. De l'etude, il ressort essentiellement que: - pour un element a uranium metallique et gaine de magnesium type G-2 ou EdF-2, on peut admettre la valeur de 0,2 deg C/W/cm{sup 2} pour des temperatures de gaines de 400 deg C et plus. - cette valeur ne depend pas de l'etat de surface microgeometrique de l'uranium pour un domaine de rugosites couvrant largement celles que l'on observe sur des tubes et barreaux fabriques en serie. - pour les gaines internes d'elements a refroidissement interne et externe la valeur de la resistance de contact reste a preciser pour les temperatures inferieures a 400 deg C, en

  15. Measures for a quality combustion (combustion chamber exit and downstream); Mesures pour une combustion de qualite (sortie de chambre de combustion et en aval)

    Energy Technology Data Exchange (ETDEWEB)

    Epinat, G. [APAVE Lyonnaise, 69 (France)

    1996-12-31

    After a review of the different pollutants related to the various types of stationary and mobile combustion processes (stoichiometric, reducing and oxidizing combustion), measures and analyses than may be used to ensure the quality and efficiency of combustion processes are reviewed: opacimeters, UV analyzers, etc. The regulation and control equipment for combustion systems are then listed, according to the generator capacity level

  16. Computational Modeling of Turbulent Spray Combustion

    NARCIS (Netherlands)

    Ma, L.

    2016-01-01

    The objective of the research presented in this thesis is development and validation of predictive models or modeling approaches of liquid fuel combustion (spray combustion) in hot-diluted environments, known as flameless combustion or MILD combustion. The goal is to combine good physical insight,

  17. Dental Encounter System (DES)

    Data.gov (United States)

    Department of Veterans Affairs — Dental Encounter System (DES) is an automated health care application designed to capture critical data about the operations of VA Dental Services. Information on...

  18. Die Wahrheit des Holocaust

    Directory of Open Access Journals (Sweden)

    Michael Stolleis

    2003-01-01

    Full Text Available Rezensiertes Werk: Raul Hilberg, Die Quellen des Holocaust. Entschlüsseln und Interpretieren. Deutsch von Udo Rennert, Frankfurt am Main: S. Fischer 2002, 256 S., ISBN 3-10-033626-7

  19. Direction des Publications

    African Journals Online (AJOL)

    Synthese

    Key words: cathode sputtering magnetron; thin films; nanostructure; corrosion; alloys Fe-Si. 1. INTRODUCTION. Les alliages de fer–Silicium (FexSiy) sont des matériaux importants, largement répandus dans des circuits électroniques et magnétiques, et jouissent d‟un excellent rapport qualité/prix. Ce succès est lie aux.

  20. typologie des parcs agroforestiers

    African Journals Online (AJOL)

    AISA

    AU SENEGAL : TYPOLOGIE DES PARCS AGROFORESTIERS. I. COLY1, L. E. AKPO1, D. SARR1, R. MALOU2, H. DACOSTA3 et F. DIOME4. 1Faculté des Sciences et ... Mots clés : Agro-écologie, parcs agro forestiers, typologie, Bas fonds de la Néma, Sénégal. .... afin d'en distinguer les sous unités, et d'en établir.

  1. Direction des Publications

    African Journals Online (AJOL)

    Synthese

    1 mai 2011 ... microscopie électronique à balayage (MEB) et la diffraction des rayons X (DRX). Nous avons effectué des essais d‟oxydation à haute température sur trois alliages binaires FeAl à 1 000 oC, dans une atmosphère d'air de laboratoire et à pression atmosphérique. Les essais d‟oxydation menés à 1000 °C ...

  2. Direction des Publications

    African Journals Online (AJOL)

    Synthese

    déclin avec le développement de la chimie de synthèse, toutefois les effets indésirables des médicaments ont ravivé l‟intérêt des scientifiques pour les plantes médicinales. C‟est ainsi que de nouvelles recherches ont vu le jour, notamment de l‟espoir de traiter certaines maladies infectieuses par les huiles essentielles.

  3. Direction des Publications

    African Journals Online (AJOL)

    Synthese

    profondes aux fosses abyssales représentant ainsi un important réservoir de biodiversité. .... des animaux menacés de l‟IUCN (Union. Internationale pour la Conservation de la. Nature) comporte plus de 100 ..... lacunes de notre compréhension des capacités de réponses et d‟adaptation de la biodiversité. Jackson et al.

  4. Combustion modeling in waste tanks

    International Nuclear Information System (INIS)

    Mueller, C.; Unal, C.; Travis, J.R.; Forschungszentrum Karlsruhe

    1997-01-01

    This paper has two objectives. The first one is to repeat previous simulations of release and combustion of flammable gases in tank SY-101 at the Hanford reservation with the recently developed code GASFLOW-II. The GASFLOW-II results are compared with the results obtained with the HMS/TRAC code and show good agreement, especially for non-combustion cases. For combustion GASFLOW-II predicts a steeper pressure rise than HMS/TRAC. The second objective is to describe a so-called induction parameter model which was developed and implemented into GASFLOW-II and reassess previous calculations of Bureau of Mines experiments for hydrogen-air combustion. The pressure time history improves compared with the one-step model, and the time rate of pressure change is much closer to the experimental data

  5. Sodium nitrate combustion limit tests

    International Nuclear Information System (INIS)

    Beitel, G.A.

    1976-04-01

    Sodium nitrate is a powerful solid oxidant. Energetically, it is capable of exothermically oxidizing almost any organic material. Rate-controlling variables such as temperature, concentration of oxidant, concentration of fuel, thermal conductivity, moisture content, size, and pressure severely limit the possibility of a self-supported exothermic reaction (combustion). The tests reported in this document were conducted on one-gram samples at atmospheric pressure. Below 380 0 C, NaNO 3 was stable and did not support combustion. At moisture concentrations above 22 wt percent, exothermic reactions did not propagate in even the most energetic and reactive compositions. Fresh resin and paraffin were too volatile to enable a NaNO 2 -supported combustion process to propagate. Concentrations of NaNO 3 above 95 wt percent or below 35 wt percent did not react with enough energy release to support combustion. The influence of sample size and confining pressure, both important factors, was not investigated in this study

  6. Fifth International Microgravity Combustion Workshop

    Science.gov (United States)

    Sacksteder, Kurt (Compiler)

    1999-01-01

    This conference proceedings document is a compilation of 120 papers presented orally or as poster displays to the Fifth International Microgravity Combustion Workshop held in Cleveland, Ohio on May 18-20, 1999. The purpose of the workshop is to present and exchange research results from theoretical and experimental work in combustion science using the reduced-gravity environment as a research tool. The results are contributed by researchers funded by NASA throughout the United States at universities, industry and government research agencies, and by researchers from at least eight international partner countries that are also participating in the microgravity combustion science research discipline. These research results are intended for use by public and private sector organizations for academic purposes, for the development of technologies needed for the Human Exploration and Development of Space, and to improve Earth-bound combustion and fire-safety related technologies.

  7. La revolution des savants

    CERN Document Server

    Chavanne, A

    1989-01-01

    Premiere cassette : - 1666 : impact de la creation de l'Academie des Sciences par Colbert, trente ans apres le proces de Galile, et au moment des disparitions de Pascal, Descartes et Fermat. Elle dirigee par le hollandais Huyggens jusqu'a sa fuite de France au moment de la revocation de l'Edit de Nantes. - 1750 : l'Encyclopedie (ou "Dictionnaire raisonne des Sciences, des Arts et des Metiers") de Diderot et d'Alembert, soutenus par Malherbes, Buffon, Condorcet et Rousseau. - 1789 : Revolution francaise. - 8 aout 1793 : l'Assemblee, par une declaration de Marat, dissout l'Academie des Sciences. Celle-ci continue cependant ses travaux pour les poids et mesures jusqu'en 1795. - la Terreur : la condamnation a mort, pas au nom d'une "Revolution qui n'a pas besoin de savants" mais pour d'autres raisons, de trois grands hommes de science : Lavoisier, Bailly et Condorcet. - 1793-1794 : Au printemps 93, le Comite de Salut Publique s'inquiete du demi-million de soldats etrangers de toutes les pays frontaliers qui essai...

  8. Smoldering Combustion Experiments in Microgravity

    Science.gov (United States)

    Walther, David C.; Fernandez-Pello, A. Carlos; Urban, David L.

    1997-01-01

    The Microgravity Smoldering Combustion (MSC) experiment is part of a study of the smolder characteristics of porous combustible materials in a microgravity environment. Smoldering is a non-flaming form of combustion that takes place in the interior of porous materials and takes place in a number of processes ranging from smoldering of porous insulation materials to high temperature synthesis of metals. The objective of the study is to provide a better understanding of the controlling mechanisms of smolder, both in microgravity and normal-gravity. As with many forms of combustion, gravity affects the availability of oxidizer and transport of heat, and therefore the rate of combustion. Microgravity smolder experiments, in both a quiescent oxidizing environment, and in a forced oxidizing flow have been conducted aboard the NASA Space Shuttle (STS-69 and STS-77 missions) to determine the effect of the ambient oxygen concentration and oxidizer forced flow velocity on smolder combustion in microgravity. The experimental apparatus is contained within the NASA Get Away Special Canister (GAS-CAN) Payload. These two sets of experiments investigate the propagation of smolder along the polyurethane foam sample under both diffusion driven and forced flow driven smoldering. The results of the microgravity experiments are compared with identical ones carried out in normal gravity, and are used to verify present theories of smolder combustion. The results of this study will provide new insights into the smoldering combustion process. Thermocouple histories show that the microgravity smolder reaction temperatures (Ts) and propagation velocities (Us) lie between those of identical normal-gravity upward and downward tests. These observations indicate the effect of buoyancy on the transport of oxidizer to the reaction front.

  9. Combustion Noise in Modern Aero-Engines

    OpenAIRE

    Duran, I.; Moreau, S.; Nicoud, F.; T., Livebardon; Bouty, E.; Poinsot, T.

    2014-01-01

    International audience; Combustion noise has recently been the subject of attention of both the aeroacoustic and the combustion research communities. Over the last decades, engine manufacturershave made important efforts to significantly reduce fan and jet noise, which increased the relative importance of combustion noise. Two main mechanisms of combustion-noise generation have been identified: direct combustion noise, generated by acoustic waves propagating to the outlet, and indirect combus...

  10. Rotary internal combustion engine

    Energy Technology Data Exchange (ETDEWEB)

    Witkowski, J.

    1989-12-05

    This patent describes an internal combustion engine assembly. It includes: a central rotor means formed with at least one peripheral fuel cavity. The cavity having a first surface defining a thrust surface and a second surface defining a contoured surface; a housing means enclosing the rotor and having an internal wall encircling the rotor. The internal wall being intercepted by at least two recesses defining cylinder means. The housing means and the rotor means being relatively rotatable; piston means individual to each the cylinder means and reciprocable therein; each piton means having a working face complementary to aid contoured surface; and power means for urging the working face into intimate areal contact with the contoured surface to create a first seal means. The housing means having at lest one fuel inlet port, at least one fuel ignition means and at least one exhaust port whereby during the course of a revolution of the rotor means relative to the housing means, the first seal means, the power means, the respective ports, the ignition means and the fuel cavity cooperate to develop fuel compression, fuel ignition and exhaust functions.

  11. Hydrogen combustion in aqueous foams

    International Nuclear Information System (INIS)

    Baer, M.R.; Griffiths, S.K.; Shepherd, J.E.

    1982-01-01

    Water fogs are recognized as an effective means to mitigate the effects of large-scale hydrogen combustion that might accompany some reactor loss-of-coolant reactor accidents. Fogs of sufficiently high density to produce large beneficial effects may, however, be difficult to generate and maintain. An alternate method of suspending the desired mass of water is via high expansion-ratio aqueous foams. Because the foam would be generated using the combustible gaseous contents of the containment vessel, combustion occurs inside the foam cells. Although foams generated with inert gas have been well studied for use in fire fighting, little is known about combustion in foams generated with flammable mixtures. To help assess the usefulness of aqueous foams in a mitigation plan, the authors have conducted open tube tests and closed vessel tests of hydrogen/air combustion with and without foam. At low and intermediate hydrogen concentrations, the foam has little effect on the ultimate isochoric pressure rise. Above 15% hydrogen concentration, the foam causes a significant reduction in the pressure rise. The maximum effect occurs at about 28% hydrogen where the peak overpressure is reduced by two and one-half. Despite this overall pressure reduction, the flame speed is increased by up to an order of magnitude for combustion in the foam and strong pressure fluctuations are observed near a hydrogen concentration of 23%

  12. Hydrogen combustion in aqueous foams

    International Nuclear Information System (INIS)

    Baer, M.R.; Griffiths, S.K.; Shepherd, J.E.

    1984-01-01

    Water fogs are recognized as an effective means to mitigate the effects of large-scale hydrogen combustion that might accompany some loss of coolant nuclear reactor accidents. Fogs of sufficiently high density to produce large beneficial effects may, however, be difficult to generate and maintain. An alternate method of suspending the desired mass of water is via high expansion-ratio aqueous foams. Because, in practice, the foam would be generated using the combustible gaseous contents of the containment vessel, combustion occurs inside the foam cells. Although foams generated with inert gas have been well studied for use in fire fighting, little is known about combustion in foams generated with flammable mixtures. To help assess the usefulness of aqueous foams in a mitigation plan, several open-tube tests and more than 100 closed-vessel tests of hydrogen/air combustion, with and without foam were conducted. At low and intermediate hydrogen concentrations, the foam has little effect on the ultimate isochoric pressure rise. Above 15% hydrogen concentration, the foam causes a significant reduction in the pressure rise. The maximum effect occurs at about 28% hydrogen (the stoichiometric limit is 29.6% hydrogen) where the peak overpressure is reduced by 2 1/2. Despite this overall pressure reduction, the flame speed is increased by up to an order of magnitude for combustion in the foam, and strong pressure fluctuations are observed near a hydrogen concentration of 23%

  13. Hydrogen combustion in aqueous foams

    International Nuclear Information System (INIS)

    Baer, M.; Griffiths, S.; Shepherd, J.

    1983-01-01

    Water fogs are recognized as an effective means to mitigate the effects of large-scale hydrogen combustion that might accompany some loss-of-coolant nuclear reactor accidents. Fogs of sufficiently high density to produce large beneficial effects may, however, be difficult to generate and maintain. An alternate method of suspending the desired mass of water is via high expansion-ratio aqueous foams. Because, in practice, the foam would be generated using the combustible gaseous contents of the containment vessel, combustion occurs inside the foam cells. Although foams generated with inert gas have been well studied for use in fire fighting, little is known about combustion in foams generated with flammable mixtures. To help assess the usefulness of aqueous foams in a mitigation plan, we have conducted several open tube tests and over one hundred closed vessel tests of hydrogen/air combustion with and without foam. At low and intermediate hydrogen concentrations, the foam has little effect on the ultimate isochoric pressure rise. Above 15% hydrogen concentration, the foam causes a significant reduction in the pressure rise. The maximum effect occurs at about 28% hydrogen (the stoichiometric limit is 29.6% hydrogen) where the peak overpressure is reduced by a factor of two and one-half. Despite this overall pressure reduction, the flame speed is increase by up to an order of magnitude for combustion in the foam and strong pressure fluctuations are observed near a hydrogen concentration of 23%

  14. Instabilités de l'écoulement interne des moteurs à propergol solide

    OpenAIRE

    Feraille, Thierry

    2004-01-01

    Les longs moteurs à propergol solide peuvent présenter des oscillations de poussée dues à des fluctuations de la pression dans la chambre de combustion. Une source de ces fluctuations peut être l'instabilité de l'écoulement interne (écoulement de Taylor), dont l’étude au sens classique a déjà été effectuée par J.Griffond (2001) sur l'écoulement monophasique. Elle est présentée au premier chapitre, ainsi que le problème des oscillations de poussée et une première analyse des mesures effectuées...

  15. Etude des comportements rheologiques des melanges de farine ble ...

    African Journals Online (AJOL)

    Etude des comportements rheologiques des melanges de farine ble/sorgho sans tanins issue de trois nouvelles varietes cultivees au Senegal et mise au point de pains a base de farines composees (ble/sorgho)

  16. Effets des biomasses vertes de Tithonia diversifolia et des engrais ...

    African Journals Online (AJOL)

    Effets des biomasses vertes de Tithonia diversifolia et des engrais minéraux sur la croissance, le développement et le rendement du manioc ( Manihot esculenta Crantz) en zone forestière du Cameroun.

  17. À propos des occasionnalismes

    Directory of Open Access Journals (Sweden)

    Dal Georgette

    2016-01-01

    Full Text Available Les occasionnalismes (nonce formations ou contextual formations dans la terminologie anglo-saxonne, qu’on définira provisoirement comme de “new complex word[s] created by a speaker/writer on the spur of the moment to cover some immediate need” (Bauer, 1983 : 45 ont, à notre connaissance, peu retenu l’attention des morphologues du domaine francophone. Pourtant, toutes les conditions sont désormais réunies pour que cet objet, invisible lorsqu’il s’agissait de décrire le système morphologique du français (ou d’autres langues à partir de ressources dictionnairiques, émerge en tant qu’observable dans une morphologie puisant ses données dans le réel langagier des locuteurs. Par définition en effet, on s’attend à ce qu’un occasionalisme soit absent des dictionnaires (nous verrons que, dans les faits, la situation est plus complexe que cela, et que ces contextual formations ne puissent pas être étudiées en dehors du contexte dans lequel elles ont été produites. À cet égard, la Toile et les produits qui en dérivent constituent des ressources de choix. C’est particulièrement vrai des forums, dans lesquels les internautes s’expriment librement, laissant libre cours à leur potentiel créatif (ou ce qu’ils pensent tel. Dans la présente communication, après avoir défini la notion d’occasionalisme, nous utiliserons un corpus constitué au fil d’autres recherches pour dégager des motifs récurrents propices à leur apparition, autrement dit pour établir une grammaire des occasionnalismes.

  18. Jet plume injection and combustion system for internal combustion engines

    Science.gov (United States)

    Oppenheim, Antoni K.; Maxson, James A.; Hensinger, David M.

    1993-01-01

    An improved combustion system for an internal combustion engine is disclosed wherein a rich air/fuel mixture is furnished at high pressure to one or more jet plume generator cavities adjacent to a cylinder and then injected through one or more orifices from the cavities into the head space of the cylinder to form one or more turbulent jet plumes in the head space of the cylinder prior to ignition of the rich air/fuel mixture in the cavity of the jet plume generator. The portion of the rich air/fuel mixture remaining in the cavity of the generator is then ignited to provide a secondary jet, comprising incomplete combustion products which are injected into the cylinder to initiate combustion in the already formed turbulent jet plume. Formation of the turbulent jet plume in the head space of the cylinder prior to ignition has been found to yield a higher maximum combustion pressure in the cylinder, as well as shortening the time period to attain such a maximum pressure.

  19. Combustion Byproducts Recycling Consortium

    Energy Technology Data Exchange (ETDEWEB)

    Paul Ziemkiewicz; Tamara Vandivort; Debra Pflughoeft-Hassett; Y. Paul Chugh; James Hower

    2008-08-31

    The Combustion Byproducts Recycling Consortium (CBRC) program was developed as a focused program to remove and/or minimize the barriers for effective management of over 123 million tons of coal combustion byproducts (CCBs) annually generated in the USA. At the time of launching the CBRC in 1998, about 25% of CCBs were beneficially utilized while the remaining was disposed in on-site or off-site landfills. During the ten (10) year tenure of CBRC (1998-2008), after a critical review, 52 projects were funded nationwide. By region, the East, Midwest, and West had 21, 18, and 13 projects funded, respectively. Almost all projects were cooperative projects involving industry, government, and academia. The CBRC projects, to a large extent, successfully addressed the problems of large-scale utilization of CCBs. A few projects, such as the two Eastern Region projects that addressed the use of fly ash in foundry applications, might be thought of as a somewhat smaller application in comparison to construction and agricultural uses, but as a novel niche use, they set the stage to draw interest that fly ash substitution for Portland cement might not attract. With consideration of the large increase in flue gas desulfurization (FGD) gypsum in response to EPA regulations, agricultural uses of FGD gypsum hold promise for large-scale uses of a product currently directed to the (currently stagnant) home construction market. Outstanding achievements of the program are: (1) The CBRC successfully enhanced professional expertise in the area of CCBs throughout the nation. The enhanced capacity continues to provide technology and information transfer expertise to industry and regulatory agencies. (2) Several technologies were developed that can be used immediately. These include: (a) Use of CCBs for road base and sub-base applications; (b) full-depth, in situ stabilization of gravel roads or highway/pavement construction recycled materials; and (c) fired bricks containing up to 30%-40% F

  20. Reseau des polygones de bord des indicateurs de performance d ...

    African Journals Online (AJOL)

    La fonction maintenance hospitalière a des composantes spécifiques qui la rendent de plus en plus complexe et fastidieuse. La politique d'une maintenance biomédicale repose sur des piliers et des leviers propres à une meilleure exploitation des dispositifs médicaux dans un système de santé. Trois niveaux de leviers ...

  1. Impact des microcredits sur les conditions sociosanitaires des ...

    African Journals Online (AJOL)

    Cependant, très peu d'étude se focalisent sur leurs impacts réels sur les conditions de vies des bénéficiaires de leurs services. C'est à ce propos que la présente recherche se donne comme objectif de contribuer à une meilleure connaissance des impacts des microcrédits - un des services offert par les IMF - sur les ...

  2. Promouvoir l'entrepreneuriat inclusif des jeunes et des femmes ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Le projet vise à analyser la contribution réelle et potentielle de l'entrepreneuriat inclusif au bien-être des jeunes et des femmes en Côte d'Ivoire, au Burkina Faso et au Kenya. Après un état des lieux de la pratique de l'entrepreneuriat inclusif dans chacun des pays ciblés, l'équipe de recherche étudiera son incidence sur ...

  3. Twenty-fifth symposium (international) on combustion

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    Approximately two-thirds of the papers presented at this conference are contained in this volume. The other one-third appear in special issues of ''Combustion and Flame'', Vol. 99, 1994 and Vol. 100, 1995. Papers are divided into the following sections: Supersonic combustion; Detonations and explosions; Internal combustion engines; Practical aspects of combustion; Incineration and wastes; Sprays and droplet combustion; Coal and organic solids combustion; Soot and polycyclic aromatic hydrocarbons; Reaction kinetics; NO x ; Turbulent flames; Turbulent combustion; Laminar flames; Flame spread, fire and halogenated fire suppressants; Global environmental effects; Ignition; Two-phase combustion; Solid propellant combustion; Materials synthesis; Microgravity; and Experimental diagnostics. Papers have been processed separately for inclusion on the data base

  4. La fabrique des sciences des institutions aux pratiques

    CERN Document Server

    Benninghoff, Martin; Crettaz von Roten, Fabienne; Merz, Martina

    2006-01-01

    Aujourd'hui, les façons de produire, d'organiser, d'évaluer et d'utiliser les savoirs sont en profond débat. De plus en plus, l'Etat, la société civile et l'économie tentent d'influencer les activités des universités et des laboratoires de recherche. Ces développements mettent à l'épreuve tout à la fois les fondements des systèmes d'enseignement supérieur et de recherche, l'autonomie des institutions scientifiques, la définition des frontières des savoirs et l'acceptation des sciences. Dans des contextes suisses et européens, cet ouvrage s'intéresse aux manières dont les sciences et les technologies sont fabriquées, en analysant leurs institutions et les pratiques. A partir d'une approche relationnelle, les sciences et les technologies sont conçues comme des phénomènes profondément sociaux, culturels et politiques. Une telle démarche déstabilise les visions parfois idéalisées et stéréotypées de la construction des savoirs. Des études de cas détaillées décrivent des phénomè...

  5. Effets des extraits vegetaux sur la dynamique de populations des ...

    African Journals Online (AJOL)

    La présente étude se propose de trouver une alternative de l'utilisation des pesticides chimiques en testant l'effet insecticide des extraits aqueux des feuilles de Hyptis suaveolens, graines de Ricinus communis et de Azadirachta indica contre les ravageurs du niébé en conditions de champ en utilisant le cyperméthrine ...

  6. Chemical Looping Combustion with Different Types of Liquid Fuels Combustion en boucle chimique avec différentes charges liquides

    Directory of Open Access Journals (Sweden)

    Hoteit A.

    2011-02-01

    Full Text Available CLC is a new promising combustion process for CO2 capture with less or even no energy penalty compared to other processes. Up to now, most of the work performed on CLC was conducted with gaseous or solid fuels, using methane and coal and/or pet coke. Liquid fuels such as heavy fuels resulting from oil distillation or conversion may also be interesting feedstocks to consider. However, liquid fuels are challenging feedstock to deal with in fluidized beds. The objective of the present work is therefore to investigate the feasibility of liquid feed injection and contact with oxygen carrier in CLC conditions in order to conduct partial or complete combustion of hydrocarbons. A batch experimental fluidized bed set-up was developed to contact alternatively oxygen carrier with liquid fuels or air. The 20 mm i.d. fluidized bed reactor was filled up with 45 g of NiAl0.44O1.67 and pulses of 1-2 g of liquid were injected in the bed at high temperatures up to 950˚C. Different feedstocks have been injected, from dodecane to heavy fuel oils No.2. Results show that, during the reduction period, it is possible to convert all the fuel injected and there is no coke remaining on particles at the end of the reduction step. Depending upon oxygen available in the bed, either full combustion or partial combustion can be achieved. Similar results were found with different liquid feeds, despite their different composition and properties. Le CLC est un nouveau concept prometteur appliqué à la combustion qui permet le captage de CO en minimisant la pénalité énergétique liée au captage. Jusqu’à présent, l’essentiel des travaux de recherche dans le domaine du CLC concerne les charges gazeuses (méthane et solides (charbon et coke. Les charges liquides, et particulièrement les résidus pétroliers, sont des charges également intéressantes à considérer a priori. La mise en oeuvre de ces charges en lit fluidisé est cependant délicate. L’objet de ce

  7. HCCI Combustion: Analysis and Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Salvador M. Aceves; Daniel L. Flowers; Joel Martinez-Frias; J. Ray Smith; Robert Dibble; Michael Au; James Girard

    2001-05-14

    Homogeneous charge compression ignition (HCCI) is a new combustion technology that may develop as an alternative to diesel engines with high efficiency and low NOx and particulate matter emissions. This paper describes the HCCI research activities being currently pursued at Lawrence Livermore National Laboratory and at the University of California Berkeley. Current activities include analysis as well as experimental work. On analysis, we have developed two powerful tools: a single zone model and a multi-zone model. The single zone model has proven very successful in predicting start of combustion and providing reasonable estimates for peak cylinder pressure, indicated efficiency and NOX emissions. This model is being applied to develop detailed engine performance maps and control strategies, and to analyze the problem of engine startability. The multi-zone model is capable of very accurate predictions of the combustion process, including HC and CO emissions. The multi-zone model h as applicability to the optimization of combustion chamber geometry and operating conditions to achieve controlled combustion at high efficiency and low emissions. On experimental work, we have done a thorough evaluation of operating conditions in a 4-cylinder Volkswagen TDI engine. The engine has been operated over a wide range of conditions by adjusting the intake temperature and the fuel flow rate. Satisfactory operation has been obtained over a wide range of operating conditions. Cylinder-to-cylinder variations play an important role in limiting maximum power, and should be controlled to achieve satisfactory performance.

  8. The Use of Fuel Gas as Stripping Medium in Atmospheric Distillation of Crude Oil L’utilisation de gaz combustible comme moyen d’extraction des fractions légères en distillation atmosphérique du pétrole brut

    OpenAIRE

    Plellis-Tsaltakis C.; Lygeros A.I.

    2011-01-01

    Stripping of petroleum fractions aims to remove the light ends that spoil some of their properties, such as the flash point. Stripping usually employs steam for that purpose. Except for steam, other substances can perform the same function, among them light hydrocarbons. In this article, we investigate the use of refinery fuel gas as stripping medium for a crude oil atmospheric distillation unit. L’extraction des fractions légères du pétrole vise à enlever les produits nuisibles à cer...

  9. Combustion Modeling with the G-Equation Modélisation de la combustion avec l'équation de G

    Directory of Open Access Journals (Sweden)

    Peters N.

    2006-12-01

    Full Text Available Numerical investigations concerning the turbulent flame front propagation in Gasoline Direct Injection (GDI engines were made by implementing a flamelet model in the CFD code Fire. The advantage of this combustion model is the decoupling of the chemistry from the turbulent flow. For this purpose the combustion chamber has to be divided into a burned and an unburned area, which is realized by transporting a scalar field (G-Equation. The reference value defines the present averaged flame position. The complete reaction kinetics is calculated interactively with the CFD code in a one dimensional Representative Interactive Flamelet (RIF code. This combustion model was verified by simulating a 2. 0 l-2 V gasoline engine with homogeneous combustion where a parameter study was conducted to check the flamelet model for plausibility. Finally, the potential of this combustion model was investigated by simulating a hypothetical 2. 0 1-4 V GDI engine. Une investigation numérique relative à la propagation des fronts de flammes turbulents dans les moteurs à essence à injection directe (GDI a été menée en implantant un modèle de flameletdans le code 3D Fire. L'avantage de ce modèle de combustion est de découpler la chimie de l'écoulement turbulent en divisant la chambre de combustion en deux zones : brûlée et imbrûlée, à l'aide d'une équation de transport d'un scalaire (équation de G. Une valeur de référence de ce scalaire définit la position moyenne de la flamme. Une chimie complète est calculée interactivement avec le calcul 3D à l'aide d'un code monodimensionnel RIF (Representative Interactive Flamelet. Le modèle de combustion a été validé sur la simulation d'un moteur 2 litres à 2 soupapes en combustion homogène pour vérifier la représentativité de l'approche flamelet . Puis, le potentiel du modèle de combustion a été étudié en simulant un moteur modèle 2 litres 4 soupapes GDI.

  10. Les lueurs des sables

    CERN Multimedia

    Les lueurs des sables

    2013-01-01

    Two CERN ladies are getting ready for the “Trophée Roses des Sables” rally adventure: Julie and Laetitia are finalizing the last details before setting off on Monday 7th October 2013. Julie from EN-MEF group and Laetitia from DGS-SEE group, met at the CERN Rugby club. This year, they are participating in the 100 % female rally which will take place in Morocco from 10 to 20 October. They will be carrying along 100 kg of humanitarian donation for children such as some clothes, books and medical material. Do not hesitate to show your support at their farewell party to be held on Monday 7 October, from 4 to 6 pm in front of the St Genis-Pouilly Mairie (city Hall). Follow their exciting adventure on the blog leslueursdessables.trophee-roses-des-sables.org and on their association’s Facebook page Les Lueurs des Sables.

  11. Characterisation of wood combustion ashes

    DEFF Research Database (Denmark)

    Maresca, Alberto

    The combustion of wood chips and wood pellets for the production of renewable energy in Denmark increased from 5.7 PJ to 16 PJ during the period 2000-2015, and further increases are expected to occur within the coming years. In 2012, about 22,300 tonnes of wood ashes were generated in Denmark....... Currently, these ashes are mainly landfilled, despite Danish legislation allowing their application onto forest and agricultural soils for fertilising and/or liming purposes. During this PhD work, 16 wood ash samples generated at ten different Danish combustion plants were collected and characterised...... for their composition and leaching properties. Despite the relatively large variations in the contents of nutrients and trace metals, the overall levels were comparable to typical ranges reported in the literature for other wood combustion ashes, as well as with regards to leaching. In general, the composition...

  12. Screening phytochimique et identification spectroscopique des ...

    African Journals Online (AJOL)

    Le screening phytochimique des feuilles et des fleurs de cette plante, effectuée pour la première fois, a révélé la présence des alcaloïdes, des flavonoïdes, des tanins catéchiques, des terpènes, des coumarines et des composés cyanogénétiques. Quant aux saponines et les quinones libres, ils sont présents chez les fleurs ...

  13. Direction des Publications

    African Journals Online (AJOL)

    Synthese

    Résumé. Dans ce travail, on s‟intéresse à l‟effet des concentrations du xanthane, du caséinate de sodium et du tween 20 sur les propriétés rhéologiques, ... macromolécules des deux biopolymères, par effet du volume exclu, auquel cas, les ..... 25 (4), 743-749. [8] Gast A.P., Hall C.K., Russel W.B.,. 1983. Polymer-induced ...

  14. Liste des tableaux

    OpenAIRE

    2014-01-01

    1 – Importations en charbon américain en Europe de l’Ouest de 1946 à 1958 .47 2 – Organisation des demandes d’allocations de charbon allemand auprès de l’eco. 75 3 – Consommations de charbon allemand dans les zones occidentales de l’Allemagne d’octobre à décembre 1945. 86 4 – Production, exportations et consommation nationale apparente du charbon allemand dans la zone britannique en 1945 et 1946. 90 5 – Total des importations de charbons allemand et américain de janvier à avril 1946. 99 6 – I...

  15. Table des tableaux

    OpenAIRE

    2018-01-01

    Tableau 1 : Production nationale d'alcool avant 1919 68 Tableau 2 : Production nationale d'alcool après 1939 (Source : Martraire, 1955, A.D. 77 : Az 7086) 71 Tableau 3 : Les surfaces agricoles disponibles en France en 2004 123 Tableau 4 : Le régime fiscal des carburants et des biocarburants en 2005 et 2006 (source : ADEME) 175 Tableau 5 : Exemple de coût de production de biocarburants (Source : Stéphane His (IFP), Les biocarburants en Europe, 2004) 176 Tableau 6 : L’application de la directiv...

  16. Combustion instability modeling and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Santoro, R.J.; Yang, V.; Santavicca, D.A. [Pennsylvania State Univ., University Park, PA (United States); Sheppard, E.J. [Tuskeggee Univ., Tuskegee, AL (United States). Dept. of Aerospace Engineering

    1995-12-31

    It is well known that the two key elements for achieving low emissions and high performance in a gas turbine combustor are to simultaneously establish (1) a lean combustion zone for maintaining low NO{sub x} emissions and (2) rapid mixing for good ignition and flame stability. However, these requirements, when coupled with the short combustor lengths used to limit the residence time for NO formation typical of advanced gas turbine combustors, can lead to problems regarding unburned hydrocarbons (UHC) and carbon monoxide (CO) emissions, as well as the occurrence of combustion instabilities. The concurrent development of suitable analytical and numerical models that are validated with experimental studies is important for achieving this objective. A major benefit of the present research will be to provide for the first time an experimentally verified model of emissions and performance of gas turbine combustors. The present study represents a coordinated effort between industry, government and academia to investigate gas turbine combustion dynamics. Specific study areas include development of advanced diagnostics, definition of controlling phenomena, advancement of analytical and numerical modeling capabilities, and assessment of the current status of our ability to apply these tools to practical gas turbine combustors. The present work involves four tasks which address, respectively, (1) the development of a fiber-optic probe for fuel-air ratio measurements, (2) the study of combustion instability using laser-based diagnostics in a high pressure, high temperature flow reactor, (3) the development of analytical and numerical modeling capabilities for describing combustion instability which will be validated against experimental data, and (4) the preparation of a literature survey and establishment of a data base on practical experience with combustion instability.

  17. Évaluation des pratiques agricoles des légumes feuilles : le cas des ...

    African Journals Online (AJOL)

    Face à ce constat, le défi de la recherche serait la détermination du niveau actuel de contamination des légumes feuilles et des eaux du barrage et celui de l'État serait l'initiation de programmes de sensibilisation des producteurs par rapport à une gestion plus rigoureuse des pesticides. Mots-clés : pratiques paysannes, ...

  18. Combustion heater for oil shale

    Science.gov (United States)

    Mallon, Richard G.; Walton, Otis R.; Lewis, Arthur E.; Braun, Robert L.

    1985-01-01

    A combustion heater for oil shale heats particles of spent oil shale containing unburned char by burning the char. A delayed fall is produced by flowing the shale particles down through a stack of downwardly sloped overlapping baffles alternately extending from opposite sides of a vertical column. The delayed fall and flow reversal occurring in passing from each baffle to the next increase the residence time and increase the contact of the oil shale particles with combustion supporting gas flowed across the column to heat the shale to about 650.degree.-700.degree. C. for use as a process heat source.

  19. Catalytic Combustion of Ethyl Acetate

    OpenAIRE

    ÖZÇELİK, Tuğba GÜRMEN; ATALAY, Süheyda; ALPAY, Erden

    2014-01-01

    The catalytic combustion of ethyl acetate over prepared metal oxide catalysts was investigated. CeO, Co2O3, Mn2O3, Cr2O3, and CeO-Co2O3 catalysts were prepared on monolith supports and they were tested. Before conducting the catalyst experiments, we searched for the homogeneous gas phase combustion reaction of ethyl acetate. According to the homogeneous phase experimental results, 45% of ethyl acetate was converted at the maximum reactor temperature tested (350 °C). All the prepare...

  20. Chemical kinetics and combustion modeling

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J.A. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    The goal of this program is to gain qualitative insight into how pollutants are formed in combustion systems and to develop quantitative mathematical models to predict their formation rates. The approach is an integrated one, combining low-pressure flame experiments, chemical kinetics modeling, theory, and kinetics experiments to gain as clear a picture as possible of the process in question. These efforts are focused on problems involved with the nitrogen chemistry of combustion systems and on the formation of soot and PAH in flames.

  1. Application of the FIRST Combustion model to Spray Combustion

    NARCIS (Netherlands)

    de Jager, B.; Kok, Jacobus B.W.

    2004-01-01

    Liquid fuel is of interest to apply to gas turbines. The large advantage is that liquids are easily storable as compared to gaseous fuels. Disadvantage is that liquid fuel has to be sprayed, vaporized and mixed with air. Combustion occurs at some stage of mixing and ignition. Depending on the

  2. Development of a Premixed Combustion Capability for Scramjet Combustion Experiments

    Science.gov (United States)

    Rockwell, Robert D.; Goyne, Christopher P.; Rice, Brian E.; Chelliah, Harsha; McDaniel, James C.; Edwards, Jack R.; Cantu, Luca M. L.; Gallo, Emanuela C. A.; Cutler, Andrew D.; Danehy, Paul M.

    2015-01-01

    Hypersonic air-breathing engines rely on scramjet combustion processes, which involve high speed, compressible, and highly turbulent flows. The combustion environment and the turbulent flames at the heart of these engines are difficult to simulate and study in the laboratory under well controlled conditions. Typically, wind-tunnel testing is performed that more closely approximates engine testing rather than a careful investigation of the underlying physics that drives the combustion process. The experiments described in this paper, along with companion data sets being developed separately, aim to isolate the chemical kinetic effects from the fuel-air mixing process in a dual-mode scramjet combustion environment. A unique fuel injection approach is taken that produces a nearly uniform fuel-air mixture at the entrance to the combustor. This approach relies on the precombustion shock train upstream of the dual-mode scramjet combustor. A stable ethylene flame anchored on a cavity flameholder with a uniformly mixed combustor inflow has been achieved in these experiments allowing numerous companion studies involving coherent anti-Stokes Raman scattering (CARS), particle image velocimetry (PIV), and planar laser induced fluorescence (PLIF) to be performed.

  3. Combustion noise and combustion instabilities in propulsion systems

    Science.gov (United States)

    Culick, F. E. C.; Paparizos, L.; Sterling, J.; Burnley, V.

    1992-01-01

    This paper is concerned with some aspects of non-linear behavior of unsteady motions in combustion chambers. The emphasis is on conditions under which organized oscillations having discrete frequencies may exist in the presence of random motions. In order to treat the two types of motions together, and particularly to investigate coupling between noise and combustion instabilities, the unsteady field is represented as a synthesis of acoustic modes having time-varying amplitudes. Each of the amplitudes are written as the sum of two parts, one associated with the random field and the remainder representing the organized oscillations. After spatial averaging, the general problem is reduced to solution of a set of second-order ordinary differential equations whose structure depends on the sorts of nonlinear processes accounted for. This formulation accommodates any physical process; in particular, terms are included to represent noise sources, although only limited modeling is discussed. Our results suggest that random sources of noise have only small effects on combustion instabilities and seem not to be a cause of unstable motions. However, the coupling between the two sorts of unsteady motions may be important as an essential process in a proposed scheme for noise control. It is now a familiar observation that many nonlinear deterministic systems are capable of exhibiting apparently random motions called 'chaos.' This is a particularly interesting possibility for systems which also executed non-deterministic random motions. In combustion chambers, a nonlinear deterministic system (acoustical motions) exists in the presence of noise produced by flow separation, turbulent motions, and energy released by combustion processes. The last part of the paper is directed to the matter of discovering whether or not chaotic motions exist in combustion systems. Analysis has not progressed sufficiently far to answer the question. We report here recent results of processing data

  4. Identification et surveillance des individus

    OpenAIRE

    Aghroum, Christian; Alberganti, Michel; Bonelli, Laurent; Ceyhan, Ayse; Denis, Vincent; Dufief, Vincent; Laurent, Sébastien; Piazza, Pierre; Preuss-Laussinotte, Sylvia; Rousselin, Thierry; Thorel, Jérôme; Tsoukala, Anastassia; Vitran, Jean-Claude; Alberganti, Michel; Alberganti, Michel

    2014-01-01

    « Big Brother is watching you ! » Cet avertissement placardé sur les murs de la cité imaginaire d'Océania dans le roman 1984 de Georges Orwell peut-il s'appliquer à nos sociétés contemporaines ? Passeport biométrique, fichage informatisé des individus, multiplication des caméras de surveillance, utilisation de puce dans des objets de la vie quotidienne, ou pour suivre les criminels en liberté surveillée, les mesures d'identification, de fichage et de surveillance des individus par des techniq...

  5. Scramjet Combustion Stability Behavior Modeling, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — A recent breakthrough in combustion stability analysis (UCDS) offers the potential to predict the combustion stability of a scramjet. This capability is very...

  6. Scramjet Combustion Stability Behavior Modeling, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — A recent breakthrough in combustion stability analysis (UCDS) offers the means to accurately predict the combustion stability of a scramjet. This capability is very...

  7. Liquid Fuel Combustion Using Porous Inert Media

    National Research Council Canada - National Science Library

    Agrawal, Ajay K; Gollahalli, Subramanayam R

    2006-01-01

    Combustion using porous inert media (PIM) offers benefits such as high power density, stable operation over a wider turndown ratio, homogeneous product gases, lower combustion noise and reduced emissions of NOx, CO, particulates, etc...

  8. Free Energy and Internal Combustion Engine Cycles

    OpenAIRE

    Harris, William D.

    2012-01-01

    The performance of one type (Carnot) of Internal Combustion Engine (ICE) cycle is analyzed within the framework of thermodynamic free energies. ICE performance is different from that of an External Combustion Engine (ECE) which is dictated by Carnot's rule.

  9. High Frequency Combustion Instabilities of LOx/CH4 Spray Flames in Rocket Engine Combustion Chambers

    NARCIS (Netherlands)

    Sliphorst, M.

    2011-01-01

    Ever since the early stages of space transportation in the 1940’s, and the related liquid propellant rocket engine development, combustion instability has been a major issue. High frequency combustion instability (HFCI) is the interaction between combustion and the acoustic field in the combustion

  10. La structure des solutions aqueuses

    Science.gov (United States)

    Powell, D. H.

    2003-09-01

    En commençant par l'étude par diffraction neutronique de la structure des liquides moléculaires puis de l'hydratation des ions en solution, ce cours montrera comment les principes présentés lors des cours précédents peuvent être appliqués à des systèmes aqueux. Des exemples tirés de la littérature seront utilisés pour illustrer les considérations expérimentales propre à ce domaine et le genre d'informations que nous pouvons obtenir. Ce cours montrera également l'applicaton de la diffraction neutronique à des systèmes d'intérêt biologique et environnemental et se terminera par un examen de la complémentarité fournie par la diffraction des rayons X, l'EXAFS et la RMN.

  11. peste des petits ruminants

    African Journals Online (AJOL)

    HP USER

    Diallo A, Minet C, Le Goff C, Berhe G, Albina E, Libeau. G, Barrett T (2007). The threat of peste des petits ruminants: progress in vaccine development for disease control. Vaccine. 25:5591–5597. Esuruoso GO (1995). The practice of preventive veterinary medicine in a devastated national economy. Being the text of an.

  12. Investir dan des solutions

    International Development Research Centre (IDRC) Digital Library (Canada)

    Gestion du risque. La gestion du risque est une responsabilité partagée entre les gestionnaires du Centre qui est intégrée à tous les processus administratifs importants. .... que préconisent les Normes internationales d'information financière (normes IFRS). TABLEAU 2. RÉPARTITION DES PRODUITS. Crédit parlementaire.

  13. Direction des Publications

    African Journals Online (AJOL)

    Synthese

    Plusieurs études cliniques et épidémiologiques ont montré que le diabète est associé à cette ... CMLs responsables de la modulation des fibroblastes en ..... Pagano P.J., 2004. Gene transfer of. NAD(P)H oxidase inhibitor to the vascular adventitia attenuates medial smooth muscle hypertrophy. Circ. Res., 95, 587-. 594.

  14. Praxis des Klebens

    CERN Document Server

    Theuerkauff, Petra

    1989-01-01

    Bei diesem Buch handelt es sich um einen Leitfaden fur Klebepraktiker. Es werden die verschiedenen Einzelschritte beim kleben beschrieben, als auch die vorbereitenden Massnahmen und anschliessenden Prufverfahren auf Festigkeit behandelt. Das Buch sollte an keinem Arbeitsplatz fehlen, wo man sich mit Problemen der Fugetechnik des Klebens beschaftigt.

  15. La physique des infinis

    CERN Document Server

    Bernardeau, Francis; Laplace, Sandrine; Spiro, Michel

    2013-01-01

    Écrire l'histoire de l'Univers, tel est l'objectif commun des physiciens des particules et des astrophysiciens. Pour y parvenir, deux approches s'épaulent : la voie de l'infiniment petit, que l'on emprunte via de gigantesques accélérateurs de particules, et celle de l'infiniment grand, dont le laboratoire est l'Univers. Un Univers qui est bien loin d'avoir livré tous ses secrets. On connaît à peine 4,8 % de la matière qui le constitue, le reste étant composé de matière noire (25,8 %) et d'énergie noire (69,4 %), toutes deux de nature inconnue. Et si la récente découverte du boson de Higgs valide le Modèle standard de la physique des particules, celui-ci est toujours incomplet et doit être étendu à ou dépassé. Est-on arrivé au bout du jeu de poupées russes de la matière ? Quelles sont les particules manquantes ? Faut-il revoir les lois fondamentales ? Quels instruments faut-il mettre en œuvre pour accéder à cette « nouvelle physique » ? Comment parler de Super Big Science aux citoye...

  16. REPRISE DES COURS - Yoga

    CERN Multimedia

    Club de Yoga

    2015-01-01

    REPRISE DES COURS – Venez nombreux ! Yoga, Sophrologie, Tai Chi La liste des cours pour le semestre allant du 1er septembre 2015 au 31 janvier 2016 est disponible sur notre site web : http://club-yoga.web.cern.ch Lieu Les cours ont lieu dans la salle des clubs, à l’entresol du restaurant No 2, Bât. 504 (dans la salle no 3 pour la Sophrologie). Prix des cours Le prix pour le semestre (environ 18 leçons) est fixé à 220 CHF plus 10 CHF d’adhésion annuelle au Club. Couple : 200 CHF par personne. 2 cours par semaine : 400 CHF. Inscriptions Les inscriptions aux cours seront prises directement auprès du professeur, lors de la 1ère séance. Avant de s’inscrire pour le semestre, il est possible d’essayer une séance gratuitement. Informations : http://club-yoga.web.cern.ch ----------------------------------------- cern.ch/club-yoga/

  17. Straw combustion on slow-moving grates

    DEFF Research Database (Denmark)

    Kær, Søren Knudsen

    2005-01-01

    Combustion of straw in grate-based boilers is often associated with high emission levels and relatively poor fuel burnout. A numerical grate combustion model was developed to assist in improving the combustion performance of these boilers. The model is based on a one-dimensional ‘‘walking...

  18. Furnaces with multiple ?ameless combustion burners

    NARCIS (Netherlands)

    Danon, B.

    2011-01-01

    In this thesis three different combustion systems, equipped with either a single or multiple ?ameless combustion burner(s), are discussed. All these setups were investigated both experimentally and numerically, i.e., using Computational Fluid Dynamics (CFD) simulations. Flameless combustion is a

  19. Method and device for diagnosing and controlling combustion instabilities in internal combustion engines operating in or transitioning to homogeneous charge combustion ignition mode

    Science.gov (United States)

    Wagner, Robert M [Knoxville, TN; Daw, Charles S [Knoxville, TN; Green, Johney B [Knoxville, TN; Edwards, Kevin D [Knoxville, TN

    2008-10-07

    This invention is a method of achieving stable, optimal mixtures of HCCI and SI in practical gasoline internal combustion engines comprising the steps of: characterizing the combustion process based on combustion process measurements, determining the ratio of conventional and HCCI combustion, determining the trajectory (sequence) of states for consecutive combustion processes, and determining subsequent combustion process modifications using said information to steer the engine combustion toward desired behavior.

  20. Recevabilité des communications par la Commission africaine des droits de l’homme et des peuples

    OpenAIRE

    Nguema, Nisrine Eba

    2014-01-01

    La Commission africaine des droits de l’homme et des peuples constitue le principal organe de protection des droits de l’homme en Afrique. Mise en place en 1987, elle a pour mission principale de recevoir les communications des victimes des violations des droits de l’homme. L’ouverture de la procédure de traitement des communications individuelles devant la Commission africaine est conditionnée par le respect des conditions posée par l’article 56 de la Charte africaine des droits de l’homme e...

  1. Leaching from biomass combustion ash

    DEFF Research Database (Denmark)

    Maresca, Alberto; Astrup, Thomas Fruergaard

    2014-01-01

    The use of biomass combustion ashes for fertilizing and liming purposes has been widely addressed in scientific literature. Nevertheless, the content of potentially toxic compounds raises concerns for a possible contamination of the soil. During this study five ash samples generated at four...

  2. Combustor nozzle for a fuel-flexible combustion system

    Science.gov (United States)

    Haynes, Joel Meier [Niskayuna, NY; Mosbacher, David Matthew [Cohoes, NY; Janssen, Jonathan Sebastian [Troy, NY; Iyer, Venkatraman Ananthakrishnan [Mason, OH

    2011-03-22

    A combustor nozzle is provided. The combustor nozzle includes a first fuel system configured to introduce a syngas fuel into a combustion chamber to enable lean premixed combustion within the combustion chamber and a second fuel system configured to introduce the syngas fuel, or a hydrocarbon fuel, or diluents, or combinations thereof into the combustion chamber to enable diffusion combustion within the combustion chamber.

  3. Injectabilite des coulis de ciment dans des milieux fissures

    Science.gov (United States)

    Mnif, Thameur

    Le travail presente ici est un bilan du travaux de recherche effectues sur l'injectabilite des coulis de ciment dans lu milieux fissures. Un certain nombre de coulis a base de ciment Portland et microfin ont ete selectionnes afin de caracteriser leur capacite a penetrer des milieux fissures. Une partie des essais a ete menee en laboratoire. L'etude rheologique des differents melanges a permis de tester l'influence de l'ajout de superplastifiant et/ou de fumee de silice sur la distribution granulometrique des coulis et par consequent sur leur capacite a injecter des colonnes de sable simulant un milieu fissure donne. La classe granulometrique d'un coulis, sa stabilite et sa fluidite sont apparus comme les trois facteurs principaux pour la reussite d'une injection. Un facteur de finesse a ete defini au cours de cette etude: base sur la classe granulometrique du ciment et sa stabilite, il peut entrer dans la formulation theorique du debit d'injection avant application sur chantier. La deuxieme et derniere partie de l'etude presente les resultats de deux projets de recherche sur l'injection realises sur chantier. L'injection de dalles de beton fissurees a permis le suivi de l'evolution des pressions avec la distance au point d'injection. L'injection de murs de maconnerie a caractere historique a montre l'importance de la definition de criteres de performance des coulis a utiliser pour traiter un milieu donne et pour un objectif donne. Plusieurs melanges peuvent ainsi etre predefinis et mis a disposition sur le chantier. La complementarite des ciments traditionnels et des ciments microfins devient alors un atout important. Le choix d'utilisation de ces melanges est fonction du terrain rencontre. En conclusion, cette recherche etablit une methodologie pour la selection des coulis a base de ciment et des pressions d'injection en fonction de l'ouverture des fissures ou joints de construction.

  4. Environmental optimisation of waste combustion

    Energy Technology Data Exchange (ETDEWEB)

    Schuster, Robert [AaF Energikonsult, Stockholm (Sweden); Berge, Niclas; Stroemberg, Birgitta [TPS Termiska Processer AB, Nykoeping (Sweden)

    2000-12-01

    The regulations concerning waste combustion evolve through R and D and a strive to get better and common regulations for the European countries. This study discusses if these rules of today concerning oxygen concentration, minimum temperature and residence time in the furnace and the use of stand-by burners are needed, are possible to monitor, are the optimum from an environmental point of view or could be improved. No evidence from well controlled laboratory experiments validate that 850 deg C in 6 % oxygen content in general is the best lower limit. A lower excess air level increase the temperature, which has a significant effect on the destruction of hydrocarbons, favourably increases the residence time, increases the thermal efficiency and the efficiency of the precipitators. Low oxygen content is also necessary to achieve low NO{sub x}-emissions. The conclusion is that the demands on the accuracy of the measurement devices and methods are too high, if they are to be used inside the furnace to control the combustion process. The big problem is however to find representative locations to measure temperature, oxygen content and residence time in the furnace. Another major problem is that the monitoring of the operation conditions today do not secure a good combustion. It can lead to a false security. The reason is that it is very hard to find boilers without stratifications. These stratifications (stream lines) has each a different history of residence time, mixing time, oxygen and combustible gas levels and temperature, when they reach the convection area. The combustion result is the sum of all these different histories. The hydrocarbons emission is in general not produced at a steady level. Small clouds of unburnt hydrocarbons travels along the stream lines showing up as peaks on a THC measurement device. High amplitude peaks has a tendency to contain higher ratio of heavy hydrocarbons than lower peaks. The good correlation between some easily detected

  5. Modélisation d'un générateur pile à combustible à électrolyte polymère

    OpenAIRE

    Chnani, Moussa

    2005-01-01

    National audience; La pile à combustible est une technologie alternative pour la propulsion des véhicules électriques. Elle est entourée par des auxiliaires (échangeurs, moto-compresseur, condenseur, humidificateur...) pour assurer l'alimentation et la gestion de l'hydrogène et de l'air. Un modèle du générateur à pile à combustible a été développé. La réponse électrique est modélisée avec une approche semi empirique. Le comportement fluidique des lignes de gaz (air + H2) est basé sur une anal...

  6. Combustion noise analysis of partially premixed combustion concept using gasoline fuel in a 2-stroke engine

    OpenAIRE

    Broatch Jacobi, Jaime Alberto; Margot , Xandra; Novella Rosa, Ricardo; Gómez-Soriano, Josep

    2016-01-01

    In the last decade, different advanced combustion concepts based on generating totally or partially premixed conditions have been investigated in CI (compression ignition) engines with the aim of achieving lower NOx (nitrous oxides) and soot emissions. Most of the drawbacks inherent to this type of combustions, such as the combustion phasing control or combustion stability, can be mitigated by combining the PPC (Partially Premixed Combustion) concept fueled by gasoline and a small...

  7. Hydrodynamique, transfert de chaleur et combustion de gaz naturel en lit fluidisé circulant Hydrodynamics, Heat Transfer and Combustion of Natural Gas in a Circulating Fluidized Bed

    Directory of Open Access Journals (Sweden)

    Feugier A.

    2006-11-01

    Full Text Available L'hydrodynamique, les transferts de chaleur et la combustion du gaz naturel ont été étudiés dans un réacteur à lit circulant de 15 cm de diamètre et de 7 m de haut. Ce réacteur peut opérer avec des vitesses de gaz allant jusqu'à 15 m/s, jusqu'à des températures de 880-900°C et avec des débits de solides compris entre 0 et 15t/h. Les charges utilisées sont des sables de granulométrie allant de 95 à 625 microns. Le profil de concentration en solides dans le réacteur est déterminé à partir du profil de pression. Une corrélation reliant la vitesse de glissement des particules aux principaux paramètres opératoires, rend compte de façon très satisfaisante de l'ensemble des résultats expérimentaux. La mise en place d'un échangeur en paroi dans la partie supérieure du réacteur a permis la détermination de coefficients d'échange thermique. Ces derniers sont essentiellement fonction de la, concentration en particules au droit de l'échangeur et de la granulométrie des particules. Des valeurs allant jusqu'à 200 W/m2 K peuvent, être obtenues. Enfin, la combustion du méthane s'avère très sensible à la présence de particules dans le réacteur. Ces particules ont un effet inhibiteur. Hydrodynamics, heat transfer and combustion of natural gas have been investigated in a circulating-bed reactor 15 cm in diameter and 7 m high. This reactor can operate with gas velocities up to 15 m/s, at temperature up to 880-900°C and with solids flow rates of between 0 and 15 t/h. The solids used are sands with a particle size ranging from 95 to 625 microns. The solids concentration profile in the reactor is determined from the pressure profile. A correlation linking the slippage velocity of particles to the principal operating parameters very satisfactorily takes into consideration the overall experimental results. The installation of a wall heat exchanger in the upper part of the reactor enabled the heat exchange coefficients to be

  8. Combustive management of oil spills

    International Nuclear Information System (INIS)

    1992-01-01

    Extensive experiments with in situ incineration were performed on a desert site at the University of Arizona with very striking results. The largest incinerator, 6 feet in diameter with a 30 foot chimney, developed combustion temperatures of 3000, F, and attendant soot production approximately 1000 times less than that produced by conventional in situ burning. This soot production, in fact, is approximately 30 times less than current allowable EPA standards for incinerators and internal combustion engines. Furthermore, as a consequence of the high temperature combustion, the bum rate was established at a very high 3400 gallons per hour for this particular 6 foot diameter structure. The rudimentary design studies we have carried out relative to a seagoing 8 foot diameter incinerator have predicted that a continuous burn rate of 7000 gallons per hour is realistic. This structure was taken as a basis for operational design because it is compatible with C130 flyability, and will be inexpensive enough ($120,000 per copy) to be stored at those seaside depots throughout the US coast line in which the requisite ancillary equipments (booms, service tugs, etc.) are already deployed. The LOX experiments verified our expectations with respect to combustion of debris and various highly weathered or emulsified oils. We have concluded, however, that the use of liquid oxygen in actual beach clean up is not promising because the very high temperatures associated with this combustion are almost certain to produce environmentally deleterious effects on the beach surface and its immediately sublying structures. However, the use of liquid oxygen augmentation for shore based and flyable incinerators may still play an important role in handing the problem of accumulated debris

  9. Utilisation des cahiers d'activites dans l'enseignement des sciences ...

    African Journals Online (AJOL)

    Les résultats des entretiens ont mis en exergue des sujets comme l'utilisation abusive des CA par certains enseignants, l'imposition des CA aux apprenants et leur coût, la qualité des contenus des CA et le maintien ou la suppression de la production des CA. D'autre part, le rendement scolaire des apprenants a été ...

  10. Modeling of Laser-Induced Metal Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Boley, C D; Rubenchik, A M

    2008-02-20

    Experiments involving the interaction of a high-power laser beam with metal targets demonstrate that combustion plays an important role. This process depends on reactions within an oxide layer, together with oxygenation and removal of this layer by the wind. We present an analytical model of laser-induced combustion. The model predicts the threshold for initiation of combustion, the growth of the combustion layer with time, and the threshold for self-supported combustion. Solutions are compared with detailed numerical modeling as benchmarked by laboratory experiments.

  11. Efficacité des néonicotinoïdes et des pyréthrinoïdes utilisés contre le ...

    African Journals Online (AJOL)

    Efficacité des néonicotinoïdes et des pyréthrinoïdes utilisés contre le foreur des tiges du cacaoyer ( Eulophonotus myrmeleon Felder : Lepidoptera, Cossidae). Implications dans la stratégie de protection de la cacaoculture en Côte d'Ivoire.

  12. Dopage et protection des jeunes sportifs : Loin des affaires

    OpenAIRE

    Guy, Daniel

    2002-01-01

    National audience; Loin des affaires et des révélations polémiques de la presse, les jeunes plébiscitent massivement les activités sportives. Sport compétition, sport participation, sport détente... Pourtant, quand la pratique devient intense, que les entraînements et les compétitions s'enchaînent à un rythme soutenu, l'ombre des conduites dopantes vient déchirer la quiétude des uns et des autres. Or, que savons-nous réellement de la pratique des jeunes sportifs ? Comment préparent-ils les co...

  13. Co-combustion of sewage sludge; Mitverbrennung von Klaerschlamm

    Energy Technology Data Exchange (ETDEWEB)

    Thome-Kozmiensky, K.J. [Technische Univ. Berlin (Germany). Fachgebiet Abfallwirtschaft

    1998-09-01

    Thermal sewage disposal pursues the following aims: destruction of organic pollutants contained in the sludge; concentration and removal or almost complete fixation of inorganic pollutants in the residue matrix; minimisation of the mass solid residue; production of useful products; utilisation of the caloric content. The thermal treatment chain should be as short as possible; intermediate stages in separate reactors such as digestion, drying, degasification or gasification should be avoided if the material is ultimately to be combusted. The present paper examines and assesses the co-combustion of sewage sludge. [Deutsch] Mit der thermischen Klaerschlammentsorgung werden folgende Ziele verfolgt: - Zerstoerung der im Schlamm enthaltenen organischen Schadstoffe, - Konzentration und Ausschleusung oder weitestgehende Fixierung der anorganischen Schadstoffe in die Reststoffmatrix, - Minimierung der Masse an festen Restabfaellen, - Herstellung verwertbarer Produkte, - Nutzung des Waermeeinhalts. Die thermische Behandlungskette sollte moeglichst kurz sein; Zwischenschritte wie Faulung, Trocknung, Ent- oder Vergasung in getrennten Reaktoren sollten vermieden werden, wenn letztendlich doch verbrannt wird. Das Verfahren der Mitverbrennung von Klaerschlamm wird hier untersucht und bewertet. (orig./SR)

  14. Aspects des Onychomycoses chez des patients camerounais de ...

    African Journals Online (AJOL)

    ... biologiques et évolutifs des onychomycoses chez des patients camerounais. Méthode : Il s'agit d'une étude rétrospective et descriptive menée de mars 2011 à mars 2014 dans l'unité de dermatologie de l'hôpital général de Douala (HGD), incluant des patients chez lesquels le diagnostic d'onychomycose avait été posé.

  15. Des dispositions responsables à prendre pour la protection des ...

    African Journals Online (AJOL)

    En considérant l'effet néfaste des maladies, des parasites, du changement climatique et d'autres facteurs environnementaux (les OGM par exemple) sur la survie des abeilles, la baisse de leurs populations dans certaines parties du monde ne saurait être attribuée aux seules pesticides. En plus, l'impact de ces derniers sur ...

  16. Collection d'entretiens avec des chercheurs participant à des ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2014-07-07

    Jul 7, 2014 ... Entretien avec…propose des entrevues vidéos avec des chercheurs participant à des projets portant sur l'adaptation aux changements climatiques réalisés en Afrique, en Asie ainsi qu'en Amérique latine et dans les Caraïbes que le CRDI subventionne par le truchement de son programme Changements ...

  17. Etat des controverses des approches cognitive et ecologique en ...

    African Journals Online (AJOL)

    Cette revue de question vise à présenter dans le champ de l'apprentissage moteur, le sens des postulats des approches cognitive et écologique de même que les critiques formulées à leur encontre. Des documents scientifiques et articles de revues indexées et publiés dans la banque de données MEDLINE, ont été ...

  18. Molten salt combustion of radioactive wastes

    International Nuclear Information System (INIS)

    Grantham, L.F.; McKenzie, D.E.; Richards, W.L.; Oldenkamp, R.D.

    1976-01-01

    The Atomics International Molten Salt Combustion Process reduces the weight and volume of combustible β-γ contaminated transuranic waste by utilizing air in a molten salt medium to combust organic materials, to trap particulates, and to react chemically with any acidic gases produced during combustion. Typically, incomplete combustion products such as hydrocarbons and carbon monoxide are below detection limits (i.e., 3 ) is directly related to the sodium chloride vapor pressure of the melt; >80% of the particulate is sodium chloride. Essentially all metal oxides (combustion ash) are retained in the melt, e.g., >99.9% of the plutonium, >99.6% of the europium, and >99.9% of the ruthenium are retained in the melt. Both bench-scale radioactive and pilot scale (50 kg/hr) nonradioactive combustion tests have been completed with essentially the same results. Design of three combustors for industrial applications are underway

  19. Distributed Low Temperature Combustion: Fundamental Understanding of Combustion Regime Transitions

    Science.gov (United States)

    2016-09-07

    turbulent premixed flows . Hence, Tau_c is here varied via the mixture stoichiometry (Phi) with variations in Tau_f pursued in a parallel study...transitions in turbulent premixed flows . Hence, τc is here varied via the mixture stoichiometry (Φ) with variations in τf pursued in a parallel study...combustion products that alter or govern the mixing fluid flow dynamics lead to a gradual alignment of Umix/Ub with the HCP fluid flow direction. This

  20. New Combustion Regimes and Kinetic Studies of Plasma Assisted Combustion

    Science.gov (United States)

    2012-11-01

    to JACS, 2012 7.1 μm Mid infra - red Faraday Rotation Spectroscopy (FRS), 1396 cm-1 Quantitative HO2 Measurement (very challenging!): 2L + 1... red absorption spectroscopy and MBMS system are developed and successfully measured H2O2 and other intermediate species. 6. A mid-infrared Faraday...flux 1000 times faster! Plasma assisted combustion dramatically changed the ”SPEED” of low temperature chemistry CH2O PLIF measurements at 355 nm

  1. Fourrages ligneux des savanes du Tchad : Etat actuel des ...

    African Journals Online (AJOL)

    Une meilleure méthode d'aménagement et de gestion des ligneux fourragers en vue de leur utilisation optimale a été proposée. Mots clés ...... Toutefois, la présence massive des rejets de souches observée au niveau des classes supérieures à [0-0,5 m[ est une forme d'adaptation et une stratégie de survie des espèces ...

  2. Direction des Publications

    African Journals Online (AJOL)

    Synthese

    Unité de Recherche des Matériaux et des Energies Renouvelables (U.R.M.E.R). Université Abou –Baker Belkaid B.p : 119 Tlemcen 13000 Algerie. 2. Unité de Développement de la Technologie Du Silicium. UDTS, BP 399, Alger, Algérie. Accepté le : 08/06/2011. صخلم. داوﻣﻟا نﻣ ﻲﺗﻟا ﺔﺻﺎﺧو ،ﺔﻋﺎﻧﺻ يأ رﯾوطﺗ ﻲﻓ ﺎﯾﺳﯾﺋر ﻼﻣﺎﻋ ةرﯾﺧﻷا تاوﻧﺳﻟا ...

  3. Table des tableaux

    OpenAIRE

    2017-01-01

    1. District de l’Inquisition de Tolède. Distances depuis le siège 19 2. District de l’Inquisition de Tolède. Répartition de la population par régions géographiques en 1591 24 3. District de l’Inquisition de Tolède. Évolution de la population au XVIe siècle par régions géographiques 25 4. Inquisition de Tolède. Origine des étrangers vieux-chrétiens jugés par le tribunal 27 5. Inquisition de Tolède. Répartition des clercs selon le type d’agglomération 55 6. District de l’Inquisition de Tolède, ...

  4. Liste des figures

    OpenAIRE

    2015-01-01

    Claudine Fabre-Vassas, Identification d'un rite 1. Ordonnance de 1779 interdisant «la méthode de guérir les hernies par la castration» 66 Christian Bromberger, Pour une ethnologie du spectacle sportif 1. La popularité relative de deux vedettes de l'Olympique de Marseille 228 2. Répartition des spectateurs marseillais dans le stade d'après leur origine résidentielle 232

  5. Direction des Publications

    African Journals Online (AJOL)

    Synthese

    7 sept. 2011 ... D‟autre part une approche statistique sera menée à partir de l‟analyse en composantes principales (ACP) afin de déterminer les processus géochimiques responsables de l‟évolution de la salinité des sols. 2. Matériel et méthodes. 2.1 Cadre physique. Le lac Fetzara est situé à 18 km au Sud-. Ouest de ...

  6. Direction des Publications

    African Journals Online (AJOL)

    Synthese

    Notre objectif est d‟élaborer des couches minces en Fe-Si par copulvérisation cathodique magnétron à différent pourcentage de silicium dans une atmosphère inerte d‟Argon et de les caractériser du point de vue physique. (composition chimique, microstructure…). Ces couches peuvent servir comme capteur magnétique.

  7. Des Ogle's old stump

    International Nuclear Information System (INIS)

    Jones, M.; Sutton, D.; Wallace, R.

    1998-01-01

    On 17 October 1997 Sylvia Bryan of RD4 Kaitaia wrote to 'Dear Somebody-Everybody' at the Anthropology Department, University of Auckland, urging further examination of an adzed stump found by Des Ogle during planting out of the Te Aupouri forest. The authors have since sought out relevant information and present it here for the interests of our readers. (author). 7 refs., 1 fig

  8. Low Temperature Combustion Demonstrator for High Efficiency Clean Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Ojeda, William de

    2010-07-31

    The project which extended from November 2005 to May of 2010 demonstrated the application of Low Temperature Combustion (LTC) with engine out NOx levels of 0.2 g/bhp-hr throughout the program target load of 12.6bar BMEP. The project showed that the range of loads could be extended to 16.5bar BMEP, therefore matching the reference lug line of the base 2007 MY Navistar 6.4L V8 engine. Results showed that the application of LTC provided a dramatic improvement over engine out emissions when compared to the base engine. Furthermore LTC improved thermal efficiency by over 5% from the base production engine when using the steady state 13 mode composite test as a benchmark. The key enablers included improvements in the air, fuel injection, and cooling systems made in Phases I and II. The outcome was the product of a careful integration of each component under an intelligent control system. The engine hardware provided the conditions to support LTC and the controller provided the necessary robustness for a stable combustion. Phase III provided a detailed account on the injection strategy used to meet the high load requirements. During this phase, the control strategy was implemented in a production automotive grade ECU to perform cycle-by-cycle combustion feedback on each of the engine cylinders. The control interacted on a cycle base with the injection system and with the Turbo-EGR systems according to their respective time constants. The result was a unique system that could, first, help optimize the combustion system and maintain high efficiency, and secondly, extend the steady state results to the transient mode of operation. The engine was upgraded in Phase IV with a Variable Valve Actuation system and a hybrid EGR loop. The impact of the more versatile EGR loop did not provide significant advantages, however the application of VVA proved to be an enabler to further extend the operation of LTC and gain considerable benefits in fuel economy and soot reduction. Finally

  9. Dictionnaire des risques psychosociaux

    CERN Document Server

    Zawieja, Philippe

    2014-01-01

    Stress, suicide, harcèlement, épuisement professionnel, workaholism... Au-delà de la souffrance qu'elles désignent, ces notions souvent récentes constituent une approche inédite, et demandent à mieux être comprises, dans leur ensemble et isolément. C'est tout l'enjeu de ce dictionnaire, pionnier en son genre. Le lecteur y trouvera représentés, avec les 314 entrées (rédigées par 251 contributeurs) qui le composent, tous les champs disciplinaires s'intéressant à la souffrance au travail : psychologie du travail et des organisations, psychologie sociale et psychosociologie, psychanalyse, psychopathologie et psychiatrie, ergonomie, sociologie du travail et des organisations, médecine du travail, droit du travail et de la sécurité sociale, sciences de gestion, philosophie... Y sont détaillés les principaux concepts, notions, approches, méthodes, théories, outils, études, etc., ayant cours dans l'étude des risques psychosociaux, mais aussi certaines professions emblématiques (infirmières,...

  10. Combustion synthesis continuous flow reactor

    Energy Technology Data Exchange (ETDEWEB)

    Maupin, G.D.; Chick, L.A.; Kurosky, R.P.

    1998-01-06

    The present invention is a reactor for combustion synthesis of inorganic powders. The reactor includes a reaction vessel having a length and a first end and a second end. The reaction vessel further has a solution inlet and a carrier gas inlet. The reactor further has a heater for heating both the solution and the carrier gas. In a preferred embodiment, the reaction vessel is heated and the solution is in contact with the heated reaction vessel. It is further preferred that the reaction vessel be cylindrical and that the carrier gas is introduced tangentially into the reaction vessel so that the solution flows helically along the interior wall of the reaction vessel. As the solution evaporates and combustion produces inorganic material powder, the carrier gas entrains the powder and carries it out of the reactor. 10 figs.

  11. Combustion synthesis continuous flow reactor

    Energy Technology Data Exchange (ETDEWEB)

    Maupin, Gary D. (Richland, WA); Chick, Lawrence A. (West Richland, WA); Kurosky, Randal P. (Maple Valley, WA)

    1998-01-01

    The present invention is a reactor for combustion synthesis of inorganic powders. The reactor includes a reaction vessel having a length and a first end and a second end. The reaction vessel further has a solution inlet and a carrier gas inlet. The reactor further has a heater for heating both the solution and the carrier gas. In a preferred embodiment, the reaction vessel is heated and the solution is in contact with the heated reaction vessel. It is further preferred that the reaction vessel be cylindrical and that the carrier gas is introduced tangentially into the reaction vessel so that the solution flows helically along the interior wall of the reaction vessel. As the solution evaporates and combustion produces inorganic material powder, the carrier gas entrains the powder and carries it out of the reactor.

  12. Steady state HNG combustion modeling

    Energy Technology Data Exchange (ETDEWEB)

    Louwers, J.; Gadiot, G.M.H.J.L. [TNO Prins Maurits Lab., Rijswijk (Netherlands); Brewster, M.Q. [Univ. of Illinois, Urbana, IL (United States); Son, S.F. [Los Alamos National Lab., NM (United States); Parr, T.; Hanson-Parr, D. [Naval Air Warfare Center, China Lake, CA (United States)

    1998-04-01

    Two simplified modeling approaches are used to model the combustion of Hydrazinium Nitroformate (HNF, N{sub 2}H{sub 5}-C(NO{sub 2}){sub 3}). The condensed phase is treated by high activation energy asymptotics. The gas phase is treated by two limit cases: the classical high activation energy, and the recently introduced low activation energy approach. This results in simplification of the gas phase energy equation, making an (approximate) analytical solution possible. The results of both models are compared with experimental results of HNF combustion. It is shown that the low activation energy approach yields better agreement with experimental observations (e.g. regression rate and temperature sensitivity), than the high activation energy approach.

  13. Oxy-coal Combustion Studies

    Energy Technology Data Exchange (ETDEWEB)

    Wendt, J. [Univ. of Utah, Salt Lake City, UT (United States); Eddings, E. [Univ. of Utah, Salt Lake City, UT (United States); Lighty, J. [Univ. of Utah, Salt Lake City, UT (United States); Ring, T. [Univ. of Utah, Salt Lake City, UT (United States); Smith, P. [Univ. of Utah, Salt Lake City, UT (United States); Thornock, J. [Univ. of Utah, Salt Lake City, UT (United States); Y Jia, W. Morris [Univ. of Utah, Salt Lake City, UT (United States); Pedel, J. [Univ. of Utah, Salt Lake City, UT (United States); Rezeai, D. [Univ. of Utah, Salt Lake City, UT (United States); Wang, L. [Univ. of Utah, Salt Lake City, UT (United States); Zhang, J. [Univ. of Utah, Salt Lake City, UT (United States); Kelly, K. [Univ. of Utah, Salt Lake City, UT (United States)

    2012-01-06

    The objective of this project is to move toward the development of a predictive capability with quantified uncertainty bounds for pilot-scale, single-burner, oxy-coal operation. This validation research brings together multi-scale experimental measurements and computer simulations. The combination of simulation development and validation experiments is designed to lead to predictive tools for the performance of existing air fired pulverized coal boilers that have been retrofitted to various oxy-firing configurations. In addition, this report also describes novel research results related to oxy-combustion in circulating fluidized beds. For pulverized coal combustion configurations, particular attention is focused on the effect of oxy-firing on ignition and coal-flame stability, and on the subsequent partitioning mechanisms of the ash aerosol.

  14. Microscale combustion and power generation

    CERN Document Server

    Cadou, Christopher; Ju, Yiguang

    2014-01-01

    Recent advances in microfabrication technologies have enabled the development of entirely new classes of small-scale devices with applications in fields ranging from biomedicine, to wireless communication and computing, to reconnaissance, and to augmentation of human function. In many cases, however, what these devices can actually accomplish is limited by the low energy density of their energy storage and conversion systems. This breakthrough book brings together in one place the information necessary to develop the high energy density combustion-based power sources that will enable many of these devices to realize their full potential. Engineers and scientists working in energy-related fields will find: An overview of the fundamental physics and phenomena of microscale combustion; Presentations of the latest modeling and simulation techniques for gasphase and catalytic micro-reactors; The latest results from experiments in small-scale liquid film, microtube, and porous combustors, micro-thrusters, a...

  15. Administrateur de programme, Application des connaissances ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Supervision. Supervision directe : Consultants et personnel temporaire, au besoin. Supervision indirecte : Consultants chargés de préparer des sommaires des résultats de recherche et des communications internes, et personnel temporaire au besoin.

  16. Noise induced phenomena in combustion

    Science.gov (United States)

    Liu, Hongliang

    Quantitative models of combustion usually consist of systems of deterministic differential equations. However, there are reasons to suspect that noise may have a significant influence. In this thesis, our primary objective is to study the effect of noise on measurable quantities in the combustion process. Our first study involves combustion in a homogeneous gas. With a one step reaction model, we analytically estimate the requirements under which noise is important to create significant differences. Our simulation shows that a bi-modality phenomenon appears when appropriate parameters are applied, which agrees with our analytical result. Our second study involves steady planar flames. We use a relatively complete chemical model of the H2/air reaction system, which contains all eight reactive species (H2, O2, H, O, OH, H2O, HO2, H2O2) and N2. Our mathematical model for this system is a reacting flow model. We derive noise terms related to transport processes by a method advocated by Landau & Lifshitz, and we also derive noise terms related to chemical reactions. We develop a code to simulate this system. The numerical implementation relies on a good Riemann solver, suitable initial and boundary conditions, and so on. We also implement a code on a continuation method, which not only can be used to study approximate properties of laminar flames under deterministic governing equations, but also eliminates the difficulty of providing a suitable initial condition for governing equations with noise. With numerical experiments, we find the difference of flame speed exist when the noise is turned on or off although it is small when compared with the influence of other parameters, for example, the equivalence ratio. It will be a starting point for further studies to include noise in combustion.

  17. Coal combustion technology in China

    International Nuclear Information System (INIS)

    Huang, Z.X.

    1994-01-01

    Coal is the most important energy source in China, the environmental pollution problem derived from coal burning is rather serious in China. The present author discusses coal burning technologies both in boilers and industrial furnaces and their relations with environmental protection problems in China. The technological situations of Circulating Fluidized Bed Coal Combustor, Pulverized Coal Combustor with Aerodynamic Flame Holder and Coal Water Slurry Combustion have been discussed here as some of the interesting problems in China only. (author). 3 refs

  18. Projektmanagement in Zeiten des Wandels

    OpenAIRE

    Papesch, Gerti

    2003-01-01

    Projektmanagement in Zeiten des Wandels : 2. Fachtagung Projektmanagement, 1. Oktober 2003 / ZWW, Zentrum für Weiterbildung und Wissenstransfer. Gerhard Wilhems ... - Augsburg : ZWW, 2003. - VI, 190 S.

  19. Hydrogen combustion in aqueous foams

    International Nuclear Information System (INIS)

    Baer, M.R.; Griffiths, S.K.; Shepherd, J.E.

    1982-09-01

    Water fogs are recognized as an effective means to mitigate the effects of large-scale hydrogen combustion that might accompany some loss-of-coolant nuclear reactor accidents. Fogs of sufficiently high density to produce large beneficial effects may, however, be difficult to generate and maintain. An alternate method of suspending the desired mass of water is via high expansion-ratio aqueous foams. To help assess the usefulness of aqueous foams in a mitigation plan, several open tube tests and over one hundred closed vessel tests of hydrogen/air combustion with and without foam have been conducted. Above 15% hydrogen concentration, the foam causes a significant reduction in the pressure rise. The maximum effect occurs at about 28% hydrogen (the stoichiometric limit is 29.6% hydrogen) where the peak overpressure is reduced by two and one-half. Despite this overall pressure reduction, the flame speed is increased by up to an order of magnitude for combustion in the foam and strong pressure fluctuations are observed near a hydrogen concentration of 23%

  20. Electrorheology Leads to Efficient Combustion

    Science.gov (United States)

    Tao, R.; Huang, K.; Tang, H.; Bell, D.

    2009-03-01

    Improving engine efficiency and reducing pollutant emissions are important. Since combustion starts at the interface between fuel and air and most harmful emissions come from incomplete burning, reducing the size of fuel droplets for the fuel injection would increase the total surface area to start burning, leading to a cleaner and more efficient engine. While most efforts are focused on ultra-dilute mixtures at extremely high pressure to produce much finer mist of fuel for combustion, the new technology is still under development and only for next generation vehicles. Here we report our fuel injection technology based on new physics principle that proper application of electrorheology can reduce the viscosity of petroleum fuels. A small device is thus introduced just before the fuel injection for the engine, producing a strong electric field to reduce the fuel viscosity, resulting in much smaller fuel droplets in atomization. Both lab tests and road tests confirm our theory and indicate that such a device improves fuel mileage significantly and reduces emission. The technology is expected to have broad applications, applicable to current internal combustion engines and future engines as well. Supported by STWA and RAND.

  1. Modeling the internal combustion engine

    Science.gov (United States)

    Zeleznik, F. J.; Mcbride, B. J.

    1985-01-01

    A flexible and computationally economical model of the internal combustion engine was developed for use on large digital computer systems. It is based on a system of ordinary differential equations for cylinder-averaged properties. The computer program is capable of multicycle calculations, with some parameters varying from cycle to cycle, and has restart capabilities. It can accommodate a broad spectrum of reactants, permits changes in physical properties, and offers a wide selection of alternative modeling functions without any reprogramming. It readily adapts to the amount of information available in a particular case because the model is in fact a hierarchy of five models. The models range from a simple model requiring only thermodynamic properties to a complex model demanding full combustion kinetics, transport properties, and poppet valve flow characteristics. Among its many features the model includes heat transfer, valve timing, supercharging, motoring, finite burning rates, cycle-to-cycle variations in air-fuel ratio, humid air, residual and recirculated exhaust gas, and full combustion kinetics.

  2. Meconnaissance des traumatismes des voies urinaires dans un ...

    African Journals Online (AJOL)

    Meconnaissance des traumatismes des voies urinaires dans un contexte de poly traumatisme: a propos de deux observations. ... They insist on good clinical assessment of abdominal trauma doubled the achievement of imaging tests to not overlook lesions of the urinary tract that can put patient's life threatening. Keywords: ...

  3. Composition chimique et effet Acaricide des huiles essentielles des ...

    African Journals Online (AJOL)

    La composition chimique et l\\'effet acaricide des huiles essentielles des feuilles de Chenopodium ambrosioides et Eucalyptus saligna vis-à-vis de Rhipicephalus lunulatus ont été évalués au Laboratoire de Chimie Appliquée et Environnementale de l\\'Université de Dschang dans l\\'Ouest du Cameroun. Cinq doses de ...

  4. Culture du bambou : diversification des moyens de subsistance des ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Culture du bambou : diversification des moyens de subsistance des petits producteurs de tabac du sud de la province de Nyanza, au Kenya - phase II. Au cours de la première phase du projet (projet no 103765), les chercheurs ont effectué une analyse de marché pour le bambou et les produits du bambou, comparé les ...

  5. Diversification des moyens de subsistance des petits producteurs de ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    L'économie du Malawi repose essentiellement sur la culture du tabac, qui représente plus de 70 % des revenus d'exportation. Pour 60 % des 100 000 membres de la National Smallholder Farmers' Association of Malawi (NASFAM), le tabac est la seule et unique source de revenus. Les cultivateurs de tabac, au Malawi ...

  6. Etude des interactions entre les differents acteurs des interventions ...

    African Journals Online (AJOL)

    Etude des interactions entre les differents acteurs des interventions sous directives communautaires et changements obtenus au Benin et au Togo. P.V. Malou Adom, Ch. P. Makoutode, T Gnaro, A.R. Ouro-Koura, E.M. Ouendo, G Napo-Koura, M Makoutode ...

  7. Effets des biomasses vertes de Tithonia diversifolia et des engrais ...

    African Journals Online (AJOL)

    Innovation (MINRESI) pour avoir financé l'intégralité des activités relatives à cette étude. RESUME. L'amélioration de la productivité des sols ferralitiques en zone forestière peut être possible grâce aux intrants locaux en complément à la fertilisation ...

  8. Gestion des ressources naturelles : des solutions avantageuses à ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    environnement et l'accès aux ressources naturelles est un enjeu crucial. Ces 40 dernières années, des chercheurs appuyés par le CRDI ont trouvé des moyens novateurs de réduire la pauvreté tout en protégeant les ressources naturelles dont ...

  9. La recherche en action : des solutions locales, des effets durables ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    15 déc. 2010 ... Le Centre de recherches pour le développement international (CRDI) appuie la production et l'application de connaissances qui améliorent de façon notable la situation des habitants des pays en développement.

  10. Roles et taches des accompagnateurs des patients hospitalises ...

    African Journals Online (AJOL)

    Roles et taches des accompagnateurs des patients hospitalises dans le service de pneumo-phtysiologie au Centre Hospitalier Universitaire Yalgado Ouedraogo de ... Logistical support represented by material support, drug supply, cleaning of premises, and littering occupied respectively 100%, 91%, 42% and 73%.

  11. Particle Emissions from Biomass Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Szpila, Aneta; Bohgard, Mats [Lund Inst. of Technology (Sweden). Div. of Ergonomics and Aerosol Technology; Strand, Michael; Lillieblad, Lena; Sanati, Mehri [Vaexjoe Univ. (Sweden). Div. of Bioenergy Technology; Pagels, Joakim; Rissler, Jenny; Swietlicki, Erik; Gharibi, Arash [Lund Univ. (Sweden). Div. of Nuclear Physics

    2003-05-01

    We have shown that high concentrations of fine particles of the order of 2-7x10{sup -7} particles per cm{sup 3} are being formed in all the combustion units studied. There was a higher difference between the units in terms of particle mass concentrations. While the largest differences was found for gas-phase constituents (CO and THC) and polyaromatic hydrocarbons. In 5 out of 7 studied units, multi-cyclones were the only measure for flue-gas separation. The multicyclones had negligible effect on the particle number concentration and a small effect on the mass of particles smaller than 5 {mu}m. The separation efficiency was much higher for the electrostatic precipitators. The boiler load had a dramatic influence on the coarse mode concentration during combustion of forest residue. PM0.8-6 increased from below 5 mg/m{sup 3} to above 50 mg/m{sup 3} even at a moderate change in boiler load from medium to high. A similar but less pronounced trend was found during combustion of dry wood. PM0.8-PM6 increased from 12 to 23 mg/m{sup 3} when the load was changed from low to high. When increasing the load, the primary airflow taken through the grate is increased; this itself may lead to a higher potential of the air stream to carry coarse particles away from the combustion zone. Measurements with APS-instrument with higher time-resolution showed a corresponding increase in coarse mode number concentration with load. Additional factor influencing observed higher concentration of coarse mode during combustion of forest residues, could be relatively high ash content in this type of fuel (2.2 %) in comparison to dry wood (0.3 %) and pellets (0.5 %). With increasing load we also found a decrease in PM1 during combustion of forest residue. Whether this is caused by scavenging of volatilized material by the high coarse mode concentration or a result of a different amount of volatilized material available for formation of fine particles needs to be shown in future studies. The

  12. IEA combustion agreement : a collaborative task on alternative fuels in combustion

    International Nuclear Information System (INIS)

    Larmi, M.

    2009-01-01

    The focus of the alternative fuels in combustion task of the International Energy Agency is on high efficiency engine combustion, furnace combustion, and combustion chemistry. The objectives of the task are to develop optimum combustion for dedicated fuels by fully utilizing the physical and chemical properties of synthetic and renewable fuels; a significant reduction in carbon dioxide, NOx and particulate matter emissions; determine the minimum emission levels for dedicated fuels; and meet future emission standards of engines without or with minimum after-treatment. This presentation discussed the alternative fuels task and addressed issues such as synthetic fuel properties and benefits. The anticipated future roadmap was presented along with a list of the synthetic and renewable engine fuels to be studied, such as neat oxygenates like alcohols and ethers, biogas/methane and gas combustion, fuel blends, dual fuel combustion, high cetane number diesel fuels like synthetic Fischer-Tropsch diesel fuel and hydrogenated vegetable oil, and low CN number fuels. Implementation examples were also discussed, such as fuel spray studies in optical spray bombs; combustion research in optical engines and combustion chambers; studies on reaction kinetics of combustion and emission formation; studies on fuel properties and ignition behaviour; combustion studies on research engines; combustion optimization; implementing the optimum combustion in research engines; and emission measurements. Overall milestone examples and the overall schedule of participating countries were also presented. figs.

  13. La diffraction des neutrons et des rayons X pour l'étude structurale des liquides et des verres

    Science.gov (United States)

    Fischer, H. E.; Salmon, P. S.; Barnes, A. C.

    2003-02-01

    La compréhension de mainte propriété physique d'un verre ou d'un liquide nécessite la connaissance des facteurs de structure partiels (PSFs) qui décrivent chacun la distribution d'une espèce atomique autour d'une autre. La technique de diffraction des neutrons avec substitution isotopique (NDIS) [1,2,3], ayant bien réussi a déterminer les PSFs de certains composés [4,5], est pourtant restreinte aux isotopes présentant un contraste suffisant en longueur de diffusion. D'un autre cote, la technique de diffusion anomale des rayons X (AXS ou AXD) [6] permet de faire varier la longueur de diffusion d'une espèce atomique pourvu que son énergie d'absorption soit à la fois accessible et suffisamment élevée pour donner un assez grand transfert du moment. La combinaison des techniques de diffraction des neutrons (avec ou sans substitution isotopique) et de diffraction des rayons X (avec ou sans diffusion anomale) peut donc permettre d'obtenir un meilleur contraste en longueurs de diffusion pour un système donné, mais exige une analyse de données plus soignée pour pouvoir bien tenir compte des erreurs systématiques qui sont différentes pour les 2 techniques [7]. Pour les atomes ayant des distributions électroniques quasi-sphériques, e.g. dans le cas d'un alliage liquide, la combinaison des techniques de NDIS et de diffraction des rayons X s'est déjà montrée très avantageuse pour la détermination des PSFs [8,9]. Dans le cas des verres ayant d'importantes liaisons covalentes, l'effective combinaison des 2 techniques peut être moins directe mais facilitée lorsqu'il s'agit des atomes de grand Z [10,11]. Nous présentons ici un sommaire du méthode et quelques exemples des résultats.

  14. The Siemens pyrolysis-combustion process; Das Siemens Schwel-Brenn-Verfahren

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, D. [Siemens - KWU, Offenbach (Germany)

    1996-12-31

    The market introduction fo the SIEMENS pyrolysis-combustion process is a technical and ecological milestone in thermal waste processing. It bridges the gap between conventional incineration and recycling and is ideally suited for the modern waste management philosophy. The innovative combination of pyrolysis followed by high-temperature combustion produces energy and reusable materials nearly without emissions. (orig/sr) [Deutsch] Die Markteinfuehrung des Schwel-Brenn-Verfahrens hat im Bereich der thermischen Muellentsorgung eine technologische und oekologische Zeitenwende eingeleitet. Es fuegt sich als Bruecke zwischen herkoemmlicher Muellverbrennung und stofflichem Muell-Recyling ideal in das Konzept einer oekologischen Kreislaufwirtschaft. Die innovative Kombination von Muellverschwelung (Pyrolyse) und anschliessender Hochtemperaturverbrennung wandelt den unvermeidbaren Restmuell nahezu rueckstandsfrei in Wertstoffe und Energie um. (orig/SR)

  15. Sandia Combustion Research Program: Annual report, 1986

    Energy Technology Data Exchange (ETDEWEB)

    1986-01-01

    This report presents research results of the past year, divided thematically into some ten categories. Publications and presentations arising from this work are included in the appendix. Our highlighted accomplishment of the year is the announcement of the discovery and demonstration of the RAPRENOx process. This new mechanism for the elimination of nitrogen oxides from essentially all kinds of combustion exhausts shows promise for commercialization, and may eventually make a significant contribution to our nation's ability to control smog and acid rain. The sections of this volume describe the facility's laser and computer system, laser diagnostics of flames, combustion chemistry, reacting flows, liquid and solid propellant combustion, mathematical models of combustion, high-temperature material interfaces, studies of engine/furnace combustion, coal combustion, and the means of encouraging technology transfer. 182 refs., 170 figs., 12 tabs.

  16. Celda combustible polimérica

    OpenAIRE

    Esquivel Bojórquez, Juan Pablo; Sabaté Vizcarra, María Neus; Santander Vallejo, Joaquín; Torres Herrero, Nuria; Gràcia Tortadès, Isabel; Cané Ballart, Carles

    2010-01-01

    La presente invención se refiere a una celda combustible polimérica fabricada con la fotoresina SU-8, todos los componentes de la celda de combustible, colectores de corriente y MEA, están fabricados en base a este mismo material. Además la presente invención también se refiere a su procedimiento de obtención y a los usos de dicha celda combustible.

  17. Numerical investigation of biogas flameless combustion

    International Nuclear Information System (INIS)

    Hosseini, Seyed Ehsan; Bagheri, Ghobad; Wahid, Mazlan Abdul

    2014-01-01

    Highlights: • Fuel consumption decreases from 3.24 g/s in biogas conventional combustion to 1.07 g/s in flameless mode. • The differences between reactants and products temperature intensifies irreversibility in traditional combustion. • The temperature inside the chamber is uniform in biogas flameless mode and exergy loss decreases in this technique. • Low O 2 concentration in the flameless mode confirms a complete and quick combustion process in flameless regime. - Abstract: The purpose of this investigation is to analyze combustion characteristics of biogas flameless mode based on clean technology development strategies. A three dimensional (3D) computational fluid dynamic (CFD) study has been performed to illustrate various priorities of biogas flameless combustion compared to the conventional mode. The effects of preheated temperature and wall temperature, reaction zone and pollutant formation are observed and the impacts of combustion and turbulence models on numerical results are discussed. Although preheated conventional combustion could be effective in terms of fuel consumption reduction, NO x formation increases. It has been found that biogas is not eligible to be applied in furnace heat up due to its low calorific value (LCV) and it is necessary to utilize a high calorific value fuel to preheat the furnace. The required enthalpy for biogas auto-ignition temperature is supplied by enthalpy of preheated oxidizer. In biogas flameless combustion, the mean temperature of the furnace is lower than traditional combustion throughout the chamber. Compared to the biogas flameless combustion with uniform temperature, very high and fluctuated temperatures are recorded in conventional combustion. Since high entropy generation intensifies irreversibility, exergy loss is higher in biogas conventional combustion compared to the biogas flameless regime. Entropy generation minimization in flameless mode is attributed to the uniform temperature inside the chamber

  18. Materials for High-Temperature Catalytic Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Ersson, Anders

    2003-04-01

    Catalytic combustion is an environmentally friendly technique to combust fuels in e.g. gas turbines. Introducing a catalyst into the combustion chamber of a gas turbine allows combustion outside the normal flammability limits. Hence, the adiabatic flame temperature may be lowered below the threshold temperature for thermal NO{sub X} formation while maintaining a stable combustion. However, several challenges are connected to the application of catalytic combustion in gas turbines. The first part of this thesis reviews the use of catalytic combustion in gas turbines. The influence of the fuel has been studied and compared over different catalyst materials. The material section is divided into two parts. The first concerns bimetallic palladium catalysts. These catalysts showed a more stable activity compared to their pure palladium counterparts for methane combustion. This was verified both by using an annular reactor at ambient pressure and a pilot-scale reactor at elevated pressures and flows closely resembling the ones found in a gas turbine combustor. The second part concerns high-temperature materials, which may be used either as active or washcoat materials. A novel group of materials for catalysis, i.e. garnets, has been synthesised and tested in combustion of methane, a low-heating value gas and diesel fuel. The garnets showed some interesting abilities especially for combustion of low-heating value, LHV, gas. Two other materials were also studied, i.e. spinels and hexa aluminates, both showed very promising thermal stability and the substituted hexa aluminates also showed a good catalytic activity. Finally, deactivation of the catalyst materials was studied. In this part the sulphur poisoning of palladium, platinum and the above-mentioned complex metal oxides has been studied for combustion of a LHV gas. Platinum and surprisingly the garnet were least deactivated. Palladium was severely affected for methane combustion while the other washcoat materials were

  19. The combustion of solid fuels and wastes

    CERN Document Server

    Tillman, David

    1991-01-01

    Careful organization and empirical correlations help clarify the prodigious technical information presented in this useful reference.Key Features* Written for practicing engineers, this comprehensive book supplies an overall framework of the combustion process; It connects information on specific reactions and reaction sequences with current applications and hardware; Each major group of combustion solids is evaluated; Among the many topics covered are:* Various biomass forms* The coalification process* Grate, kiln, and suspension firing* Fluidized bed combustion

  20. Combustion gas from biomass - innovative plant concepts on the basis of circulating fluidized bed gasification; Brenngas aus Biomasse - innovative Anlagenkonzepte auf Basis der Zirkulierenden Wirbelschichtvergasung

    Energy Technology Data Exchange (ETDEWEB)

    Greil, C.; Hirschfelder, H. [Lurgi Umwelt GmbH, Frankfurt am Main (Germany)

    1998-09-01

    The contribution describes the applications of the Lurgi-ZWS gas generator. There are three main fields of application: Direct feeding of combustion gas, e.g. into a rotary kiln, as a substitute for coal or oil, without either dust filtering or gas purification. - Feeding of the combustion gas into the steam generator of a coal power plant after dust filtering and, if necessar, filtering of NH{sub 3} or H{sub 2}S. - Combustion in a gas turbine or gas engine after gas purification according to specifications. The applications are described for several exemplary projects. (orig./SR) [Deutsch] Im folgenden wird ueber die Anwendung des Lurgi-ZWS-Gaserzeugers berichtet. Nach heutiger Sicht stehen drei Anwendungsgebiete im Vordergrund: - direkte Einspeisung des Brenngases in z.B. einen Zementdrehrohrofen zur Substitution von Kohle oder Oel, ohne Entstaubung und Gasreinigung. - Einspeisung des Brenngases nach Entstaubung und gegebenenfalls Entfernung weiterer Komponenten wie NH{sub 3} oder H{sub 2}S in den Dampferzeuger eines Kohlekraftwerkes - Einsatz des Brenngases in einer Gasturbine oder Gasmotor nach spezifikationsgerechter Gasreinigung. Die aufgefuehrten Einsatzmoeglichkeiten werden am Beispiel von Projekten beschrieben. (orig./SR)

  1. La cogestion des Ressources naturelles

    International Development Research Centre (IDRC) Digital Library (Canada)

    Comprend des réf. bibliogr. ISBN 1-55250-329-1. 1. Cogestion des ressources naturelles—Pays en voie de développement—Cas, Études de. 2. Conservation ...... De fait, les villageois en imputaient la faute aux fonctionnaires nationaux et locaux qui n'avaient pas su mettre efficacement en oeuvre les politiques forestières.

  2. 14 CFR 25.859 - Combustion heater fire protection.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Combustion heater fire protection. 25.859....859 Combustion heater fire protection. (a) Combustion heater fire zones. The following combustion... surrounds the combustion chamber. However, no fire extinguishment is required in cabin ventilating air...

  3. 14 CFR 29.859 - Combustion heater fire protection.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Combustion heater fire protection. 29.859... § 29.859 Combustion heater fire protection. (a) Combustion heater fire zones. The following combustion... any ventilating air passage that— (i) Surrounds the combustion chamber; and (ii) Would not contain...

  4. High Impact Technology Compact Combustion (HITCC) Compact Core Technologies

    Science.gov (United States)

    2016-01-01

    were combusted in a vitiated stream. The molecular weight and hydrogen -to-carbon ratios of these fuels were measured by Princeton University [17...AFRL-RQ-WP-TR-2016-0010 HIGH IMPACT TECHNOLOGY COMPACT COMBUSTION (HITCC) COMPACT CORE TECHNOLOGIES Andrew W. Caswell Combustion ...ANDREW W. CASWELL CHARLES J. CROSS, Branch Chief Program Engineer Combustion Branch Combustion Branch Turbine Engine Division Turbine

  5. 46 CFR 105.10-10 - Combustible liquid.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Combustible liquid. 105.10-10 Section 105.10-10 Shipping... Combustible liquid. (a) The term combustible liquid means any liquid having a flashpoint above 80 °F. (as..., combustible liquids are referred to by grades, as follows: (1) Grade D. Any combustible liquid having a...

  6. Développement de matériaux pour les piles à combustibles SOFC

    Science.gov (United States)

    Dubourdieu, G.; Gauthier, G.; Henry, J. Y.; Sanchette, F.; Delépine, J.; Lefebvre-Joud, F.

    2002-04-01

    Dans le cadre des nouveaux programmes du CEA dédiés aux Nouvelles Technologies pour l'Energie, l'un des axes concerne les piles à combustible haute température et tout solide (SOFC). Deux voies de recherche sont présentées ici ; l'une traite de l'élaboration d'électrolytes connus - de type zircone yttriée - en couche mince, par des techniques de dépôt PVD ou CVD à injection, ceci dans le but d'un fonctionnement à plus basse température. L'autre a trait au développement de matériaux d'anode compatibles avec l'utilisation directe du méthane à la place de l'hydrogène. Les chromates de lanthane substitué par le strontium, dont une méthode de synthèse sous forme de poudres très divisées est présentée ici, semblent être des matériaux prometteurs pour cette application, à condition qu'ils ne subissent pas de dégradation en fonctionnement.

  7. Engine Valve Actuation For Combustion Enhancement

    Science.gov (United States)

    Reitz, Rolf Deneys; Rutland, Christopher J.; Jhavar, Rahul

    2004-05-18

    A combustion chamber valve, such as an intake valve or an exhaust valve, is briefly opened during the compression and/or power strokes of a 4-stroke combustion cycle in an internal combustion engine (in particular, a diesel or CI engine). The brief opening may (1) enhance mixing withing the combustion chamber, allowing more complete oxidation of particulates to decrease engine emissions; and/or may (2) delay ignition until a more desirable time, potentially allowing a means of timing ignition in otherwise difficult-to-control conditions, e.g., in HCCI (Homogeneous Charge Compression Ignition) conditions.

  8. Pressurized Fluidized Bed Combustion of Sewage Sludge

    Science.gov (United States)

    Suzuki, Yoshizo; Nojima, Tomoyuki; Kakuta, Akihiko; Moritomi, Hiroshi

    A conceptual design of an energy recovering system from sewage sludge was proposed. This system consists of a pressurized fluidized bed combustor, a gas turbine, and a heat exchanger for preheating of combustion air. Thermal efficiency was estimated roughly as 10-25%. In order to know the combustion characteristics of the sewage sludge under the elevated pressure condition, combustion tests of the dry and wet sewage sludge were carried out by using laboratory scale pressurized fluidized bed combustors. Combustibility of the sewage sludge was good enough and almost complete combustion was achieved in the combustion of the actual wet sludge. CO emission and NOx emission were marvelously low especially during the combustion of wet sewage sludge regardless of high volatile and nitrogen content of the sewage sludge. However, nitrous oxide (N2O) emission was very high. Hence, almost all nitrogen oxides were emitted as the form of N2O. From these combustion tests, we judged combustion of the sewage sludge with the pressurized fluidized bed combustor is suitable, and the conceptual design of the power generation system is available.

  9. Pyrolysis reactor and fluidized bed combustion chamber

    Science.gov (United States)

    Green, Norman W.

    1981-01-06

    A solid carbonaceous material is pyrolyzed in a descending flow pyrolysis reactor in the presence of a particulate source of heat to yield a particulate carbon containing solid residue. The particulate source of heat is obtained by educting with a gaseous source of oxygen the particulate carbon containing solid residue from a fluidized bed into a first combustion zone coupled to a second combustion zone. A source of oxygen is introduced into the second combustion zone to oxidize carbon monoxide formed in the first combustion zone to heat the solid residue to the temperature of the particulate source of heat.

  10. Direction des Publications

    African Journals Online (AJOL)

    Synthese

    diabète et le tabagisme sont des facteurs de risque reconnus [2-4]. Les données épidémiologiques recueillies au cours de ces trente dernières années laissent ... réduction d‟expression du gène LOX-1 et de la libération de TNFα stimulée par les. LDL-oxydées [22]. Chez l‟homme, in vivo, Voutilainen et al. [23] ont mis en ...

  11. COMPLICATIONS CHIRURGICALES DES AVORTEMENTS ...

    African Journals Online (AJOL)

    1 janv. 2004 ... liquide purulent, sérosanguinolent, ou fécaloïde. Les lésions retrouvées étaient classées en lésions utérines et annexielles (Tableau I), lésions ... femmes par an dans le Monde d'après l'Organisation. Mondiale de la Santé [15]. Leur fréquence élevée dans notre série impose une prise systématique des ...

  12. Direction des Publications

    African Journals Online (AJOL)

    Synthese

    Revue Synthèse N° 22, Décembre 2010. N. Benrachou et al. 19. Tableau 3. Composition en triglycérides des trois huiles d'olive). Blanquette. Limli. Bouricha. Variétés. Triglycérides. N° pic. NCE. 3,24 ± 0,01. 2,86± 0,02. 1,06 ± 0,03. LLL. 1. 42. 2,97 ± 0,01. 2,15 ± 0,07. 1,71 ± 0,06. OLLn +PoLL. 2. 0,21 ± 0,01. 0,66 ± 0,02.

  13. Liste des auteurs

    OpenAIRE

    2016-01-01

    Garry Apgar The Voltair Society of America, New York Jean Balcou Université de Bretagne occidentale, Brest Annie Becq Université de Caen Paul Benhamou. Purdue University, West Lafayette, Indiana Reed Benhamou Indiana University, Bloomington, Indiana Jacqueline Biard-Millerioux Université de Poitiers Françoise Bléchet Bibliothèque nationale de France, département des manuscrits, Paris Nicolas Brucker Université de Metz Else-Marie Bukdahl The Royal Danish Academy of Fine Art, Copenhague Christo...

  14. Gestion des ressources naturelles

    International Development Research Centre (IDRC) Digital Library (Canada)

    Mais la situation évolue grâce aux travaux du Réseau international sur le bam- bou et le rotin (INBAR), créé par le CRDI dans les années 1990. À Allahabad, en Inde, la culture du bam- bou a permis de rétablir la fertilité des sols dégradés par l'extraction de l'argile nécessaire à la fabrication de briques, et les agriculteurs.

  15. Aspects chimiques de la combustion du charbon pulvérisé. Première partie Chemical Aspects of the Combustion of Pulverized Coal. Part One

    Directory of Open Access Journals (Sweden)

    De Soete G. G.

    2006-11-01

    Full Text Available II n'est pas facile de parvenir à une vue complète des multiples phénomènes chimiques dont la flamme de charbon pulvérisé est le siège. La présente étude bibliographique s'efforce de donner plus qu'une juxtaposition des données de la littérature récente, en risquant une tentative de présentation cohérente des mécanismes chimiques clés qui s'affrontent dans cette combustion. Ces mécanismes font intervenir des réactions en phase gazeuse relativement rapides (combustion des produits gazeux de pyrolyse, formation d'oxydes d'azote à partir de l'azote organique ainsi qu'un certain nombre de réactions hétérogènes très importantes (dévolatilisation pyrolysante rapide, oxydation du coke, réduction hétérogène d'oxydes d'azote qui peuvent se dérouler de façon beaucoup plus lente. En ce qui concerne ces dernières, le régime non isotherme, auquel les soumet l'existence de gradients de température dans la flamme industrielle, entraîne souvent des conséquences non négligeables pour le déroulement de ces mécanismes cinétiques complexes : ainsi la quantité et la composition des produits de pyrolyse est fortement tributaire de ces conditions non isothermes. Carrefour de plusieurs mécanismes chimiques complexes, la flamme de charbon est caractérisée chimiquement par un grand nombre de cas de compétition : a compétition entre différentes voies réactionnelles à l'intérieur d'un mécanisme donné ; à titre d'exemple typique : la pyrolyse du charbon ; b compétition entre phénomènes chimiques et physiques, également à l'intérieur d'un même mécanisme, entraînant la transition éventuellement réversible d'un régime cinétique vers un régime diffusionnel, comme c'est le cas dans l'oxydation du coke, avec des conséquences sensibles pour la vitesse réactionnelle globale et sa dépendance par rapport à la température, pouvant même aller jusqu'à l'extinction de la combustion du coke ; c compétition entre

  16. Ageing Mechanisms and Control. Specialists’ Meeting on Life Management Techniques for Ageing Air Vehicles (Les mecanismes vieillissants et le controle) (Reunions des specialistes des techniques de gestion du cycle de vie pour vehicules aeriens vieillissants)

    Science.gov (United States)

    2003-02-01

    technologies d’inspection non- destructive, de la réparation, des modifications, de la prévention, de l’analyse et du contrôle de l’état des moteurs . Elle...Principles for Improved Airworthiness of Rotorcraft MP-24, January 2000 Gas Turbine Engine Combustion , Emissions and Alternative Fuels MP-14, June...Cracking Experiences in the USAF,” Published in the Proceedings of the 22nd International Congress of Aeronautical Sciences, August 2000. 2. Negaard, G. R

  17. Pulsed atmospheric fluidized bed combustion

    Energy Technology Data Exchange (ETDEWEB)

    1989-11-01

    In order to verify the technical feasibility of the MTCI Pulsed Atmospheric Fluidized Bed Combustor technology, a laboratory-scale system was designed, built and tested. Important aspects of the operational and performance parameters of the system were established experimentally. A considerable amount of the effort was invested in the initial task of constructing an AFBC that would represent a reasonable baseline against which the performance of the PAFBC could be compared. A summary comparison of the performance and emissions data from the MTCI 2 ft {times} 2 ft facility (AFBC and PAFBC modes) with those from conventional BFBC (taller freeboard and recycle operation) and circulating fluidized bed combustion (CFBC) units is given in Table ES-1. The comparison is for typical high-volatile bituminous coals and sorbents of average reactivity. The values indicated for BFBC and CFBC were based on published information. The AFBC unit that was designed to act as a baseline for the comparison was indeed representative of the larger units even at the smaller scale for which it was designed. The PAFBC mode exhibited superior performance in relation to the AFBC mode. The higher combustion efficiency translates into reduced coal consumption and lower system operating cost; the improvement in sulfur capture implies less sorbent requirement and waste generation and in turn lower operating cost; lower NO{sub x} and CO emissions mean ease of site permitting; and greater steam-generation rate translates into less heat exchange surface area and reduced capital cost. Also, the PAFBC performance generally surpasses those of conventional BFBC, is comparable to CFBC in combustion and NO{sub x} emissions, and is better than CFBC in sulfur capture and CO emissions even at the scaled-down size used for the experimental feasibility tests.

  18. Utilisation sans risque des eaux usées, des excréta et des eaux ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Les responsables de ce projet piloteront l'application et l'adaptation des principes directeurs relatifs à l'utilisation sans risque des eaux usées, des excreta et des eaux grises en agriculture et en aquaculture (Guidelines for the Safe Use of Wastewater, Excreta and Greywater in Agriculture and Aquaculture), que ...

  19. Sulfur Chemistry in Combustion II

    DEFF Research Database (Denmark)

    Johnsson, Jan Erik; Kiil, Søren

    2000-01-01

    Several options are available to control the emission of SO2 from combustion processes. One possibility is to use a cleaner technology, i.e. fuel switching from oil and coal to natural gas or biomass, or to desulphurize coal and oil. Another possibility is to change to a different technology...... for power production, such as sun, wind or nuclear power. However, presently and in the near future the most important technology to reduce SO2 emissions from power production is flue gas desulphurization (FGD). There are several methods of FGD, but the majority of the plants are wet scrubbers...

  20. COMBUSTION PROPERTIES OF EUCALYPTUS WOOD

    Directory of Open Access Journals (Sweden)

    Yalçın ÖRS

    1999-03-01

    Full Text Available In this study, the combustion properties of some impregnation materials (abiotic and biotic factors used for eucalyptus wood in interior or exterior environments were investigated. The experimental samples were prepared from Eucalyptus wood based on ASTM-D-1413-76 Tanalith-CBC, boric acid, borax, vacsol-WR, immersol-WR, polyethylen glycole-400 and ammonium sulphate were used as an impregnation material. The results indicated that, vacuum treatment on Eucalyptus gave the lowest retention value of salts. Compounds containing boron+salt increased fire resistance however water repellents decreased the wood flammability.

  1. Theoretical studies of combustion dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, J.M. [Emory Univ., Atlanta, GA (United States)

    1993-12-01

    The basic objectives of this research program are to develop and apply theoretical techniques to fundamental dynamical processes of importance in gas-phase combustion. There are two major areas currently supported by this grant. One is reactive scattering of diatom-diatom systems, and the other is the dynamics of complex formation and decay based on L{sup 2} methods. In all of these studies, the authors focus on systems that are of interest experimentally, and for which potential energy surfaces based, at least in part, on ab initio calculations are available.

  2. Modeling nitrogen chemistry in combustion

    DEFF Research Database (Denmark)

    Glarborg, Peter; Miller, James A.; Ruscic, Branko

    2018-01-01

    Understanding of the chemical processes that govern formation and destruction of nitrogen oxides (NOx) in combustion processes continues to be a challenge. Even though this area has been the subject of extensive research over the last four decades, there are still unresolved issues that may limit...... via NNH or N2O are discussed, along with the chemistry of NO removal processes such as reburning and Selective Non-Catalytic Reduction of NO. Each subset of the mechanism is evaluated against experimental data and the accuracy of modeling predictions is discussed....

  3. Rôle des feux de savane sur les caractéristiques biogéochimiques ...

    African Journals Online (AJOL)

    Les feux de brousse dont les effets dépendent aussi bien de leurs intensités ainsi que de leur saison d'occurrence, sont considérés comme une perturbation écologique majeure des écosystèmes savanicoles. L'objectif général de cette étude est de générer des connaissances sur l'effet de la quantité du combustible et de ...

  4. Chirurgie des grassmanniennes

    CERN Document Server

    Lafforgue, Laurent

    2003-01-01

    Les compactifications diverses de variétés de modules sont un thème important et récurrent des mathématiques modernes, et elles connaissent un grand nombre d'applications. Ce livre traite le cas de cellules de Schubert minces, qui sont de sous-variétés naturelles de grassmanniennes. L'auteur a été amené à traiter ces questions par un cas particulier lié à ses travaux sur le programme de Langlands. Dans cette monographie, il en développe une théorie plus systématique, présentant le fortes similarités avec celle des modules du courbes stables. The various compactifications of moduli spaces are an important recurrent theme of modern mathematics, and they have a large number of applications. This book treats the case of thin Schubert varieties, which are natural subvarieties of Grassmannians. The author was led to these questions by a particular case linked to his work on the Langlands program. In this monograph, he develops the theory in a more systematic way, which exhibits strong similarities...

  5. Mécanique des sols et des roches

    CERN Document Server

    Vullier, Laurent; Zhao, Jian

    2016-01-01

    La mécanique des sols et la mécanique des roches sont des disciplines généralement traitées séparément dans la littérature. Pour la première fois, un traité réunit ces deux spécialités, en intégrant également les connaissances en lien avec les écoulements souterrains et les transferts thermiques. A la fois théorique et pratique, cet ouvrage propose tout d'abord une description détaillée de la nature et de la composition des sols et des roches, puis s'attache à la modélisation de problèmes aux conditions limites et présente les essais permettant de caractériser les sols et les roches, tant d'un point de vue mécanique qu'hydraulique et thermique. La problématique des sols non saturés et des écoulements multiphasiques est également abordée. Une attention particulière est portée aux lois de comportement mécanique et à la détermination de leurs paramètres par des essais in situ et en laboratoire, et l'ouvrage offre également une présentation détaillée des systèmes de classi...

  6. Perception des producteurs sur l'utilisation des déjections de ...

    African Journals Online (AJOL)

    Objectif: L'étude vise à analyser la perception des producteurs sur la contribution des chenilles dans la gestion de la fertilité des sols et dans la production des ... Les producteurs enquêtés ont par ailleurs, identifié les facteurs anthropiques, climatiques et édaphiques comme les facteurs pouvant influencer la dynamique des ...

  7. Combustion

    National Research Council Canada - National Science Library

    Glassman, Irvin

    1996-01-01

    ... permission in writing from the publisher. Permissions may be sought directly from Elsevier's Science and Technology Rights Department in Oxford, UK. Phone (44) 1865 843830, Fax: (44) 1865 853333, e-mail: permissions@elsevier.co.uk. You may also complete your request on-line via the Elsevier homepage: http://www.elsevier.com by selecting "...

  8. La Flore Des Adventices Des Cultures Cotonnieres De La Region ...

    African Journals Online (AJOL)

    A partir de relevés itinérants réalisés dans des cultures cotonnières de la région du Worodougou, en Côte d\\'Ivoire, précisement à Mankono, Dianra et Séguéla, 230 espèces d\\'adventices ont été recensées. Dans chacune des trois localités inventoriées, il apparaît que les familles des Poaceae, Fabaceae et Asteraceae ...

  9. Evaluation de la gestion des dechets issus des activites de ...

    African Journals Online (AJOL)

    Le moyen d'élimination des déchets utilisé est l'incinération. Tous les agents impliqués dans la vaccination ont une connaissance des risques de contamination liés aux déchets vaccinaux. La gestion des déchets reste un système global dont tous les aspects méritent d'être considérés. Chaque étape de l'élimination est ...

  10. Low NOx combustion technologies for high-temperature natural gas combustion

    International Nuclear Information System (INIS)

    Flamme, Michael

    1999-01-01

    Because of the high process temperature which is required for some processes like glass melting and the high temperature to which the combustion air is preheated, NOx emission are extremely high. Even at these high temperatures, NOx emissions could be reduced drastically by using advanced combustion techniques such as staged combustion or flame-less oxidation, as experimental work has shown. In the case of oxy-fuel combustion, the NOx emission are also very high if conventional burners are used. The new combustion techniques achieve similar NOx reductions. (author)

  11. Ultra-low pollutant emission combustion method and apparatus

    International Nuclear Information System (INIS)

    Khinkis, M.J.

    1992-01-01

    This patent describes a method for ultra-low pollutant emission combustion of fossil fuel. It comprises: introducing into a primary combustion chamber a first fuel portion of about 1 percent to about 20 percent of a total fuel to be combusted; introducing primary combustion air into the primary combustion chamber; introducing a first portion of water into the primary combustion chamber, having a first water heat capacity equivalent to a primary combustion air heat capacity of one of a primary combustion air amount of about 10 percent to about 60 percent of the first stoichiometirc requirement for complete combustion of the first fuel portion and an excess primary combustion air amount of about 20 percent to about 150 percent of the first stoichiometric requirement for complete combustion of the first fuel portion; burning the first fuel portion with the primary combustion air in the primary combustion chamber at a temperature abut 2000 degrees F to about 2700 degrees F producing initial combustion products; passing the initial combustion products into a secondary combustion chamber; introducing into the secondary combustion chamber a second fuel portion of about 80 percent to about 99 percent of the total fuel to be combusted; introducing secondary combustion air into the secondary combustion chamber in an amount of about 105 percent to about 130 percent of a second stoichiometric requirement for complete combustion of the second fuel portion; introducing a second portion of water into the secondary combustion chamber; burning the second fuel portion and any remaining fuel in the initial combustion products; passing the final combustion products into a dilution chamber; introducing dilution air into the dilution chamber; discharging the ultra-low pollutant emission vitiated air form the dilution chamber

  12. Evaluation des activites antihyperglycemiantes d'extraits aqueux de ...

    African Journals Online (AJOL)

    écorce de Casuarina equisetifolia révèle la présence des alcaloïdes, des tanins, des flavonoïdes, des leucoanthocyanes, des dérivés anthracéniques, des coumarines et des composés réducteurs, composés aux propriétés médicales multiples, ...

  13. Cars diagnostics for combustion and plasma processes

    International Nuclear Information System (INIS)

    Eckbreth, A.C.; Stufflebeam, J.H.

    1988-01-01

    Coherent anti-Stokes Raman spectroscopy (CARS) is an analysis approach for nonintrusive temperature and species measurements in hostile environments. Widely utilized in combustion, it may be able to significantly impact materials processing research. CARS is described. Its applications to combustion and plasma process environments are reviewed and contrasted

  14. Coal combustion ashes: A radioactive Waste?

    International Nuclear Information System (INIS)

    Michetti, F.P.; Tocci, M.

    1992-01-01

    The radioactive substances naturally hold in fossil fuels, such as Uranium and Thorium, after the combustion, are subjected to an increase of concentration in the residual combustion products as flying ashes or as firebox ashes. A significant percentage of the waste should be classified as radioactive waste, while the political strategies seems to be setted to declassify it as non-radioactive waste. (Author)

  15. Combustion synthesis and photoluminescence study of silicate ...

    Indian Academy of Sciences (India)

    Silicate based bioceramics are promising candidates as biomaterials for tissue engineering. The combustion synthesis method provides control on the morphology and particle size of the synthesized material. This paper discusses the combustion synthesis of akermanite (Ca2MgSi2O7 and Sr2MgSi2O7), which has been ...

  16. Combustion and extinction of magnesium fires

    International Nuclear Information System (INIS)

    Malet, J.C.; Duverger de Cuy, G.

    1988-01-01

    The studies made in France on magnesium combustion and extinguishing means are associated at the nuclear fuel of the graphite-gas reactor. Safety studies are made for ameliorate our knowledge on: - magnesium combustion - magnesium fire propagation - magnesium fire extinguishing [fr

  17. Flue Gas Emissions from Fluidized Bed Combustion

    NARCIS (Netherlands)

    Bramer, E.A.; Valk, M.

    1995-01-01

    During the past decades fluidized bed coal combustion was developed as a technology for burning coal in an effective way meeting the standards for pollution control. During the earlier years of research on fluidized bed combustion, the potential for limiting the S02 emission by adding limestone to

  18. Coal slurry combustion and technology. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    1983-01-01

    Volume II contains papers presented at the following sessions of the Coal Slurry Combustion and Technology Symposium: (1) bench-scale testing; (2) pilot testing; (3) combustion; and (4) rheology and characterization. Thirty-three papers have been processed for inclusion in the Energy Data Base. (ATT)

  19. Internal combustion engines in hybrid vehicles

    NARCIS (Netherlands)

    Mourad, S.; Weijer, C.J.T. van de; Beckman, D.E.

    1998-01-01

    In this paper the use of internal combustion engines in hybrid powertrains is investigated. The substantial difference between the use of internal combustion engines in conventional and in hybrid vehicles mean that engines for hybrid vehicles should be designed specifically for the purpose. At the

  20. Sandia combustion research program: Annual report, 1987

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, R.E.; Sanders, B.R.; Ivanetich, C.A. (eds.)

    1988-01-01

    More than a decade ago, in response to a national energy crisis, Sandia proposed to the US Department of Energy a new, ambitious program in combustion research. Our strategy was to apply the rapidly increasing capabilities in lasers and computers to combustion science and technology. Shortly thereafter, the Combustion Research Facility (CRF) was established at Sandia's Livermore location. Designated a ''User Facility,'' the charter of the CRF was to develop and maintain special-purpose resources to support a nationwide initiative--involving US universities, industry, and national laboratories--to improve our understanding and control of combustion. This report includes descriptions of several research projects which have been stimulated by Working Groups and involve the on-site participation of industry scientists. DOE's Industry Technology Fellowship Program has been instrumental in the success of some of the joint efforts. The remainder of this report presents research results of calendar year 1987, separated thematically into nine categories. Refereed journal articles appearing in print during 1987, along with selected other publications, are included at the end of Section 10. In addition to our ''traditional'' research--chemistry, reacting flow, diagnostics, engine combustion, and coal combustion--you will note continued progress in somewhat recent themes: pulse combustion, high temperature materials, and energetic materials, for example. Moreover, we have just started a small, new effort to understand combustion-related issues in the management of toxic and hazardous materials.

  1. Injector tip for an internal combustion engine

    Science.gov (United States)

    Shyu, Tsu Pin; Ye, Wen

    2003-05-20

    This invention relates to a the tip structure of a fuel injector as used in a internal combustion engine. Internal combustion engines using Homogeneous Charge Compression Ignition (HCCI) technology require a tip structure that directs fuel spray in a downward direction. This requirement necessitates a tip design that is capable of withstanding mechanical stresses associated with the design.

  2. A model for premixed combustion oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Janus, M.C.; Richards, G.A.

    1996-09-01

    This paper describes a simulation based on a time dependent, nonlinear control volume analysis. The combustion is modeled as a well-stirred reactor having finite kinetics. Flow properties and species in the nozzle, combustion, and tailpipe regions are determined using a control volume formulation of the conservation equation.

  3. A predictive model of natural gas mixture combustion in internal combustion engines

    Directory of Open Access Journals (Sweden)

    Henry Espinoza

    2007-05-01

    Full Text Available This study shows the development of a predictive natural gas mixture combustion model for conventional com-bustion (ignition engines. The model was based on resolving two areas; one having unburned combustion mixture and another having combustion products. Energy and matter conservation equations were solved for each crankshaft turn angle for each area. Nonlinear differential equations for each phase’s energy (considering compression, combustion and expansion were solved by applying the fourth-order Runge-Kutta method. The model also enabled studying different natural gas components’ composition and evaluating combustion in the presence of dry and humid air. Validation results are shown with experimental data, demonstrating the software’s precision and accuracy in the results so produced. The results showed cylinder pressure, unburned and burned mixture temperature, burned mass fraction and combustion reaction heat for the engine being modelled using a natural gas mixture.

  4. Internal and surface phenomena in metal combustion

    Science.gov (United States)

    Dreizin, Edward L.; Molodetsky, Irina E.; Law, Chung K.

    1995-01-01

    Combustion of metals has been widely studied in the past, primarily because of their high oxidation enthalpies. A general understanding of metal combustion has been developed based on the recognition of the existence of both vapor-phase and surface reactions and involvement of the reaction products in the ensuing heterogeneous combustion. However, distinct features often observed in metal particle combustion, such as brightness oscillations and jumps (spearpoints), disruptive burning, and non-symmetric flames are not currently understood. Recent metal combustion experiments using uniform high-temperature metal droplets produced by a novel micro-arc technique have indicated that oxygen dissolves in the interior of burning particles of certain metals and that the subsequent transformations of the metal-oxygen solutions into stoichiometric oxides are accompanied with sufficient heat release to cause observed brightness and temperature jumps. Similar oxygen dissolution has been observed in recent experiments on bulk iron combustion but has not been associated with such dramatic effects. This research addresses heterogeneous metal droplet combustion, specifically focusing on oxygen penetration into the burning metal droplets, and its influence on the metal combustion rate, temperature history, and disruptive burning. A unique feature of the experimental approach is the combination of the microgravity environment with a novel micro-arc Generator of Monodispersed Metal Droplets (GEMMED), ensuring repeatable formation and ignition of uniform metal droplets with controllable initial temperature and velocity. The droplet initial temperatures can be adjusted within a wide range from just above the metal melting point, which provides means to ignite droplets instantly upon entering an oxygen containing environment. Initial droplet velocity will be set equal to zero allowing one to organize metal combustion microgravity experiments in a fashion similar to usual microgravity

  5. Engagements contractuels et performances des organisations de ...

    African Journals Online (AJOL)

    amélioration des performances des organisations des producteurs (OP) à l'Ouest Cameroun. Il est basé sur des enquêtes par questionnaires auprès des délégués de 33 OP de maïs bénéficiaires de l'encadrement du Programme d'Amélioration de la ...

  6. Médecine des voyages

    Science.gov (United States)

    Aw, Brian; Boraston, Suni; Botten, David; Cherniwchan, Darin; Fazal, Hyder; Kelton, Timothy; Libman, Michael; Saldanha, Colin; Scappatura, Philip; Stowe, Brian

    2014-01-01

    Résumé Objectif Définir la pratique de la médecine des voyages, présenter les éléments fondamentaux d’une consultation complète préalable aux voyages à des voyageurs internationaux et aider à identifier les patients qu’il vaudrait mieux envoyer en consultation auprès de professionnels de la médecine des voyages. Sources des données Les lignes directrices et les recommandations sur la médecine des voyages et les maladies liées aux voyages publiées par les autorités sanitaires nationales et internationales ont fait l’objet d’un examen. Une recension des ouvrages connexes dans MEDLINE et EMBASE a aussi été effectuée. Message principal La médecine des voyages est une spécialité très dynamique qui se concentre sur les soins préventifs avant un voyage. Une évaluation exhaustive du risque pour chaque voyageur est essentielle pour mesurer avec exactitude les risques particuliers au voyageur, à son itinéraire et à sa destination et pour offrir des conseils sur les interventions les plus appropriées en gestion du risque afin de promouvoir la santé et prévenir les problèmes médicaux indésirables durant le voyage. Des vaccins peuvent aussi être nécessaires et doivent être personnalisés en fonction des antécédents d’immunisation du voyageur, de son itinéraire et du temps qu’il reste avant son départ. Conclusion La santé et la sécurité d’un voyageur dépendent du degré d’expertise du médecin qui offre le counseling préalable à son voyage et les vaccins, au besoin. On recommande à ceux qui donnent des conseils aux voyageurs d’être conscients de l’ampleur de cette responsabilité et de demander si possible une consultation auprès de professionnels de la médecine des voyages pour tous les voyageurs à risque élevé.

  7. Solid waste combustion for alpha waste incineration

    International Nuclear Information System (INIS)

    Orloff, D.I.

    1981-02-01

    Radioactive waste incinerator development at the Savannah River Laboratory has been augmented by fundamental combustion studies at the University of South Carolina. The objective was to measure and model pyrolysis and combustion rates of typical Savannah River Plant waste materials as a function of incinerator operating conditions. The analytical models developed in this work have been incorporated into a waste burning transient code. The code predicts maximum air requirement and heat energy release as a function of waste type, package size, combustion chamber size, and temperature. Historically, relationships have been determined by direct experiments that did not allow an engineering basis for predicting combustion rates in untested incinerators. The computed combustion rates and burning times agree with measured values in the Savannah River Laboratory pilot (1 lb/hr) and full-scale (12 lb/hr) alpha incinerators for a wide variety of typical waste materials

  8. 2003 Laser Diagnostic in Combustion Conference

    Energy Technology Data Exchange (ETDEWEB)

    Mark G. Allen

    2004-09-10

    The GRC Laser Diagnostics in Combustion aims at bringing together scientists and engineers working in the front edge of research and development to discuss and find new ways to solve problems connected to combustion diagnostics. Laser-based techniques have proven to be very efficient tools for studying combustion processes thanks to features as non-intrusiveness in combination with high spatial and temporal resolution. Major tasks for the community are to develop and apply techniques for quantitative measurements with high precision e.g of species concentrations, temperatures, velocities and particles characteristics (size and concentration). These issues are of global interest, considering that the major part of the World's energy conversion comes from combustion sources and the influence combustion processes have on the environment and society.

  9. Interactive wood combustion for botanical tree models

    KAUST Repository

    Pirk, Sören

    2017-11-22

    We present a novel method for the combustion of botanical tree models. Tree models are represented as connected particles for the branching structure and a polygonal surface mesh for the combustion. Each particle stores biological and physical attributes that drive the kinetic behavior of a plant and the exothermic reaction of the combustion. Coupled with realistic physics for rods, the particles enable dynamic branch motions. We model material properties, such as moisture and charring behavior, and associate them with individual particles. The combustion is efficiently processed in the surface domain of the tree model on a polygonal mesh. A user can dynamically interact with the model by initiating fires and by inducing stress on branches. The flames realistically propagate through the tree model by consuming the available resources. Our method runs at interactive rates and supports multiple tree instances in parallel. We demonstrate the effectiveness of our approach through numerous examples and evaluate its plausibility against the combustion of real wood samples.

  10. Influence des facteurs agro-écologiques et des herbicides sur le ...

    African Journals Online (AJOL)

    Influence des facteurs agro-écologiques et des herbicides sur le rendement et les caractéristiques technologiques des grains et farines de blés tendres ( Triticum aestivum L.) et durs ( Triticum durum Desf.)

  11. Distributed combustion in a cyclonic burner

    Science.gov (United States)

    Sorrentino, Giancarlo; Sabia, Pino; de Joannon, Mara; Cavaliere, Antonio; Ragucci, Raffaele

    2017-11-01

    Distributed combustion regime occurs in several combustion technologies were efficient and environmentally cleaner energy conversion are primary tasks. For such technologies (MILD, LTC, etc…), working temperatures are enough low to boost the formation of several classes of pollutants, such as NOx and soot. To access this temperature range, a significant dilution as well as preheating of reactants is required. Such conditions are usually achieved by a strong recirculation of exhaust gases that simultaneously dilute and pre-heat the fresh reactants. However, the intersection of low combustion temperatures and highly diluted mixtures with intense pre-heating alters the evolution of the combustion process with respect to traditional flames, leading to significant features such as uniformity and distributed ignition. The present study numerically characterized the turbulence-chemistry and combustion regimes of propane/oxygen mixtures, highly diluted in nitrogen, at atmospheric pressure, in a cyclonic combustor under MILD Combustion operating conditions. The velocity and mixing fields were obtained using CFD with focus on mean and fluctuating quantities. The flow-field information helped differentiate between the impact of turbulence levels and dilution ones. The integral length scale along with the fluctuating velocity is critical to determine Damköhler and Karlovitz numbers. Together these numbers identify the combustion regime at which the combustor is operating. This information clearly distinguishes between conventional flames and distributed combustion. The results revealed that major controllers of the reaction regime are dilution and mixing levels; both are significantly impacted by lowering oxygen concentration through entrainment of hot reactive species from within the combustor, which is important in distributed combustion. Understanding the controlling factors of distributed regime is critical for the development and deployment of these novel combustion

  12. Evaluation des pratiques de gestion des adventices en riziculture ...

    African Journals Online (AJOL)

    Le riz est l'aliment principal pour la quasi-totalité des populations vivant en Côte d'Ivoire. Cependant, les adventices sont considérées comme la contrainte biologique la plus importante faisant obstacle à la production rizicole. L'objectif de cette étude menée en 2015 était d'évaluer différentes techniques de gestion des ...

  13. Des agriculteurs trouvent des moyens d'exploiter les avantages ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    19 sept. 2013 ... Le tout dernier prototype sera adapté en vue de son utilisation dans les collectivités et les villages. On continuera d'y apporter des améliorations pour lui permettre de moudre d'autres mils (le pied de coq et l'herbe à épée ou kodo). Des chercheurs de la Tamil Nadu Agricultural University s'emploient aussi ...

  14. Modernisation des marchés agroalimentaires - inclusion des petits ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Les marchés agroalimentaires connaissent de rapides changements dans les pays en développement et les pays en transition. Sous l'influence de la libéralisation du commerce et des nouvelles technologies de transformation des aliments et de commerce de détail, les marchés agroalimentaires évoluent vers une plus ...

  15. Therapie des Harnwegsinfekts

    Directory of Open Access Journals (Sweden)

    Stoiser B

    2010-01-01

    Full Text Available Harnwegsinfektionen gehören zu den häufigsten entzündlichen Erkrankungen im niedergelassenen Bereich. Eine intelligente Therapiestrategie stellt damit nicht nur eine klinische Herausforderung dar, sondern ermöglicht rasche Heilung, Vermeidung von Resistenzbildungen sowie oft unnötiger, teurer diagnostischer Schritte. Der erste entscheidende Schritt ist die genaue Klassifizierung des Harnweginfektes – asymptomatische Bakteriurie bis zur komplizierten Pyelonephritis. Hier entscheiden sich bereits Aggressivität der Behandlung sowie diagnostischer Aufwand. Für die Entwicklung einer empirischen antimikrobiellen Therapie ist die Kenntnis der häufigsten Erreger sowie lokaler Resistenzmuster wichtig. Bei gezieltem Vorgehen können die meisten Harnwegsinfekte ohne erhöhten diagnostischen Aufwand therapiert werden.

  16. Code des baux 2018

    CERN Document Server

    Vial-Pedroletti, Béatrice; Kendérian, Fabien; Chavance, Emmanuelle; Coutan-Lapalus, Christelle

    2017-01-01

    Le code des baux 2018 vous offre un contenu extrêmement pratique, fiable et à jour au 1er août 2017. Cette 16e édition intègre notamment : le décret du 27 juillet 2017 relatif à l’évolution de certains loyers dans le cadre d’une nouvelle location ou d’un renouvellement de bail, pris en application de l’article 18 de la loi n° 89-462 du 6 juillet 1989 ; la loi du 27 janvier 2017 relative à l’égalité et à la citoyenneté ; la loi du 9 décembre 2016 relative à la transparence, à la lutte contre la corruption et à la modernisation de la vie économique ; la loi du 18 novembre 2016 de modernisation de la justice du xxie siècle

  17. Dry low NOx combustion system with pre-mixed direct-injection secondary fuel nozzle

    Science.gov (United States)

    Zuo, Baifang; Johnson, Thomas; Ziminsky, Willy; Khan, Abdul

    2013-12-17

    A combustion system includes a first combustion chamber and a second combustion chamber. The second combustion chamber is positioned downstream of the first combustion chamber. The combustion system also includes a pre-mixed, direct-injection secondary fuel nozzle. The pre-mixed, direct-injection secondary fuel nozzle extends through the first combustion chamber into the second combustion chamber.

  18. Nitrous Oxide from Combustion and Industry: Chemistry, Emissions and Control Protoxyde d'azote provenant de la combustion et de l'industrie : chimie, émissions et techniques de réduction

    Directory of Open Access Journals (Sweden)

    De Soete G.

    2006-11-01

    Full Text Available After an Introductory Part, presenting a survey of the present knowledge of nitrous oxide chemistry related to fossil fuel combustion and flue gas treatment, as a background for the understanding of emission factors, the paper deals successively with the average N2O emission factors from combustion and other industrial sources, and gives guidelines for appropriate N2O control technology ; with respect to the former item, some comments and criticisms on the 1991 OEDC/IPCC Report are formulated. As far as updated emission sources are concerned, emphasis is put on those which presently constitute issues : emissions from fluidized bed combustors, emissions caused by non catalytic selective NO reduction by ammonia and urea injection, N2O emissions caused by the use of automotive three-way catalysts as well as emissions from nitric acid and adipic acid manufacturing and from municipal wastes and sewage sludges incineration. Comments on the 1991 OEDC/IPCC Report mainly emphasize : (1 the surprising absence of emission factors from stationary combustion facilities and the inadequacy of some of the scarcely presented data, (2 the strange ignorance of the important effect of aging of three-way catalysts on the emission of N2O from gasoline vehicles. These omissions are the more surprising since reliable information in these two fields were already available at the period the OEDC Report was issued and or revised. For the assessment of adequate N2O control technologies, there is an urgent need for further R&D work. Presently existing understanding of homogeneous and heterogeneous N2O chemistry may provide interesting hints for N2O control, either by gas phase treatment or by catalytic reduction, depending on the concentration levels present in the off-gases to be treated. Le but de cet article est double : d'une part il fait le point sur les facteurs d'émission de N2O provenant de la combustion des combustibles fossiles et de certains autres secteurs de l

  19. Ajustement du rechargement et des mecanismes de reactivite des reacteurs CANDU pour les cycles de combustible avances

    Science.gov (United States)

    St-Aubin, Emmanuel

    This research project main objectives are to set up and apply a methodology that can determine the potential of advanced thorium-based fuel cycles in CANDU reactors and that is able to adjust reactivity devices, in such a way as to maintain their reference efficiency for these new fuels. In order to select these fuel cycles, a large alternative fuel envelope is submitted to several discriminating criteria. A coarse parametric core modeling, that takes into account standard reactivity devices, is first used to highlight candidates presenting the best economical performances and to eliminate non viable options. Then, for the best candidates, the neutronic modeling is optimized before considering reactivity devices adjustment. For every reactivity device managed by the reactor regulating system, innovative generic optimization methods are used to achieve specific objectives for every fuel cycle, all of them being based on the reference natural uranium cycle behavior. Specific optimization objectives are assessed by simulating advanced fuel cycle for specific operating conditions, including : normal on-power refueling period, spurious reactor trip and fueling machine unavailibility. Unlike the generalized perturbative approach proposed in the OPTEX code, we have successfully implemented a multi-step method able to maximize both the energy extracted from the fuel using an equilibrium refueling optimization, and the reactivity devices adequacy. We also propose new reactivity device supercell models that provides accurate reactor databases for a fraction of the computing cost usually needed using a full model with a similar spatial discretization. Our approach is verified by comparing our simulation results with results published in the literature for the reference fuel cycle. The methodology developed identified advanced fuel cycles, containing up to 60%v. thorium, thereby increasing resources utilization by more than 50% and multiplying the fuel average exit burn-up by a factor of 4.4 when compared with the reference cycle. The reactivity devices were also retained after our optimization processes, requiring only minor modifications to the original design. We determined that a 10%v. heavy water doping of the light water within liquid zone controllers could increase the average exit burnup of the reference cycle by almost 1%, without any adverse consequence to the reactor control. This method is validated through its systematic application to numerous different cases. It demonstrates its capability to achieve very different objectives related to reactivity devices requirements, thus it can be now used for other similar studies.

  20. Analysis and modelling of the fuels european market; Analyse et modelisation des prix des produits petroliers combustibles en europe

    Energy Technology Data Exchange (ETDEWEB)

    Simon, V

    1999-04-01

    The research focus on the European fuel market prices referring to the Rotterdam and Genoa spot markets as well the German, Italian and French domestic markets. The thesis try to explain the impact of the London IPE future market on spot prices too. The mainstream research has demonstrated that co-integration seems to be the best theoretical approach to investigate the long run equilibrium relations. A particular attention will be devoted to the structural change in the econometric modelling on these equilibriums. A deep analysis of the main European petroleum products markets permit a better model specification concerning each of these markets. Further, we will test if any evidence of relations between spot and domestic prices could be confirmed. Finally, alternative scenarios will be depicted to forecast prices in the petroleum products markets. The objective is to observe the model reaction to changes crude oil prices. (author)

  1. Prise en compte du gonflement des terrains dans le dimensionnement des revêtements des tunnels

    OpenAIRE

    Bultel, Frédéric

    2001-01-01

    Travail préparé au Laboratoire Central des Ponts et Chaussées (LCPC-Paris) dans le cadre d'une convention CIFRE avec la société Scetauroute,Composition du jury : MM. R. KASTNER professeur à l'Institut National des Sciences Appliquées de Lyon (rapporteur),I. SHAHROUR professeur à l'Ecole Universitaire Des Ingénieurs de Lille (rapporteur), P. EGGER professeur à l'Ecole Polytechnique Fédérale de Lausanne (Examinateur), B. GAUDIN expert géotechnique à Scetauroute-DTTS (Examinateur), J.P. MAGNAN D...

  2. Nanoparticle emissions from combustion engines

    CERN Document Server

    Merkisz, Jerzy

    2015-01-01

     This book focuses on particulate matter emissions produced by vehicles with combustion engines. It describes the physicochemical properties of the particulate matter, the mechanisms of its formation and its environmental impacts (including those on human beings). It discusses methods for measuring particulate mass and number, including the state-of-the-art in Portable Emission Measurement System (PEMS) equipment for measuring the exhaust emissions of both light and heavy-duty vehicles and buses under actual operating conditions. The book presents the authors’ latest investigations into the relations between particulate emission (mass and number) and engine operating parameters, as well as their new findings obtained through road tests performed on various types of vehicles, including those using diesel particulate filter regeneration. The book, which addresses the needs of academics and professionals alike, also discusses relevant European regulations on particulate emissions and highlights selected metho...

  3. Digitalisierung des Kulturellen Erbes (Europas)

    NARCIS (Netherlands)

    Gruber, Marion

    2011-01-01

    Gruber, M. R. (2011, 13 December). Digitalisierung des Kulturellen Erbes (Europas). Guest lecture at the IPMZ - Institute of Mass Communication and Media Research, Devision Media Change & Innovation, University of Zurich, Switzerland.

  4. Methodolgy for the Diagnostic of the Combustion Process of an Idi Diesel Engine Méthodologie pour le diagnostic du processus de combustion dans un moteur Diesel à injection indirecte

    Directory of Open Access Journals (Sweden)

    Payri F.

    2006-11-01

    Full Text Available Measurement of pressure in the pre-chamber and in the main chamber of an indirect injection Diesel engine provide useful information for the interpretation of the combustion process. However, this is not easy because pressure signals are affected by a number of simultaneous processes such as compression, heat transfer and heat release, and mass exchange between chambers. Diagnostic models try to separate these effects by providing heat release laws which describe with detail the combustion process timing. The whole diagnostic procedure, which is simple and accurate in the case of DI Diesel engines, becomes more complex in IDI ones, and requires much care in calibration, filtering and adjustment because most of the information depends on differences between pressure in the two chambers, whose absolute values are only slightly higher than the accuracy of the pressure measurements. In this work a methodology for the experimental diagnostic is described. The methodology covers the engine testing in both motored and firing conditions, the pressure signal acquisition and processing, the determination of the engine dynamic characteristics, the adjustment of a diagnostic mathematical model, and the final interpretation of the pressure signals through the diagnostic model. Finally, some examples of application are presented. La mesure de la pression dans la préchambre et la chambre principale d'un moteur Diesel à injection indirecte permet d'obtenir une information très utile pour l'interprétation du processus de combustion. Cependant, cette analyse est rendue difficile par le fait que les signaux de pression contiennent l'effet simultané de divers processus, comme la compression, la transmission de chaleur aux parois, le dégagement de chaleur et l'échange de masse entre les deux chambres. L'objectif des modèles de diagnostic est d'isoler ces effets afin d'obtenir des lois de dégagement de chaleur qui décrivent en détail l

  5. La cogestion des Ressources naturelles

    International Development Research Centre (IDRC) Digital Library (Canada)

    Le Liban — les conflits sur les ressources et la modification des moyens de subsistance à Arsaal . 71. Chapitre ..... Ainsi, un seul arbre d'une forêt peut fournir des fruits, du bois de chauffage, du fourrage et de l'ombrage; constituer un stabilisateur du sol et un habitat faunique et représenter un lien avec l'identité ancestrale.

  6. CONTRAINTES INSTITUTIONNELLES ET LABELLISATION DES ...

    African Journals Online (AJOL)

    de labellisation des produits algériens (particulièrement le vin et les dattes) par le biais des indications géographiques et les contraintes institutionnels et territoriales qui contrarient ce processus. Le contexte algérien, très marqué par une économie mono-ex- portatrice et très dépendante à l'égard d'un seul type de produit, ...

  7. Effect of Variant End of Injection Period on Combustion Process of Biodiesel Combustion

    Directory of Open Access Journals (Sweden)

    Khalid Amir

    2016-01-01

    Full Text Available Biodiesel is an alternative fuel as a replacement to the standard diesel fuel in combustion diesel engine. The biodiesel fuel has a significantly influences throughout the combustion process and exhaust emission. The purpose of this research is to investigate the combustion process behavior during the End of Injection (EOI period and operates under variant conditions using Rapid Compression Machine (RCM. Experimental of RCM is used to simulate a combustion process and combustion characteristics of diesel engine combustion. Three types of biodiesel blend which are B5, B10 and B15 were tested at several injection pressures of 80 MPa, 90 MPa and 130 MPa under different ambient temperatures, 750 K to 1100 K. The results of this study showed that the ignition delay slightly reduced with increasing the content of biodiesel blends from B5, B10 and B15 and became more shorten as the injection pressure been enhanced. As the injection pressure increased, the behavior of combustion pressure at end of injection is reduced, radically increased the NOX emission. It is noted that the process of combustion at the end of injection increased as the ambient temperature is rising. In fact, higher initial ambient temperature improved the fuel atomization and mixing process. Under the biodiesel combustion with higher ambient temperature condition, the exhaust emission of CO, O2, and HC became less but increased in NOX emission. Besides, increased in blends of biodiesel ratio are found to enhance the combustion process, resulted a decreased in HC emissions.

  8. Extended lattice Boltzmann scheme for droplet combustion.

    Science.gov (United States)

    Ashna, Mostafa; Rahimian, Mohammad Hassan; Fakhari, Abbas

    2017-05-01

    The available lattice Boltzmann (LB) models for combustion or phase change are focused on either single-phase flow combustion or two-phase flow with evaporation assuming a constant density for both liquid and gas phases. To pave the way towards simulation of spray combustion, we propose a two-phase LB method for modeling combustion of liquid fuel droplets. We develop an LB scheme to model phase change and combustion by taking into account the density variation in the gas phase and accounting for the chemical reaction based on the Cahn-Hilliard free-energy approach. Evaporation of liquid fuel is modeled by adding a source term, which is due to the divergence of the velocity field being nontrivial, in the continuity equation. The low-Mach-number approximation in the governing Navier-Stokes and energy equations is used to incorporate source terms due to heat release from chemical reactions, density variation, and nonluminous radiative heat loss. Additionally, the conservation equation for chemical species is formulated by including a source term due to chemical reaction. To validate the model, we consider the combustion of n-heptane and n-butanol droplets in stagnant air using overall single-step reactions. The diameter history and flame standoff ratio obtained from the proposed LB method are found to be in good agreement with available numerical and experimental data. The present LB scheme is believed to be a promising approach for modeling spray combustion.

  9. Bifurcation, pattern formation and chaos in combustion

    International Nuclear Information System (INIS)

    Bayliss, A.; Matkowsky, B.J.

    1991-01-01

    In this paper problems in gaseous combustion and in gasless condensed phase combustion are studied both analytically and numerically. In gaseous combustion we consider the problem of a flame stabilized on a line source of fuel. The authors find both stationary and pulsating axisymmetric solutions as well as stationary and pulsating cellular solutions. The pulsating cellular solutions take the form of either traveling waves or standing waves. Transitions between these patterns occur as parameters related to the curvature of the flame front and the Lewis number are varied. In gasless condensed phase combustion both planar and nonplanar problems are studied. For planar condensed phase combustion we consider two models: accounts for melting and does not. Both models are shown to exhibit a transition from uniformly to pulsating propagating combustion when a parameter related to the activation energy is increased. Upon further increasing this parameter both models undergo a transition to chaos: by intermittency and by a period doubling sequence. In nonplanar condensed phase combustion the nonlinear development of a branch of standing wave solutions is studied and is shown to lead to relaxation oscillations and subsequently to a transition to quasi-periodicity

  10. Catalytic combustion in small wood burning appliances

    Energy Technology Data Exchange (ETDEWEB)

    Oravainen, H. [VTT Energy, Jyvaeskylae (Finland)

    1996-12-31

    There is over a million hand fired small heating appliances in Finland where about 5,4 million cubic meters of wood fuel is used. Combustion in such heating appliances is a batch-type process. In early stages of combustion when volatiles are burned, the formation of carbon monoxide (CO) and other combustible gases are difficult to avoid when using fuels that have high volatile matter content. Harmful emissions are formed mostly after each fuel adding but also during char burnout period. When the CO-content in flue gases is, say over 0.5 %, also other harmful emissions will be formed. Methane (CH{sub 4}) and other hydrocarbons are released and the amount of polycyclic aromatic hydrocarbons (PAH)-compounds can be remarkable. Some PAH-compounds are very carcinogenic. It has been estimated that in Finland even more than 90 % of hydrocarbon and PAH emissions are due to small scale wood combustion. Emissions from transportation is excluded from these figures. That is why wood combustion has a net effect on greenhouse gas phenomena. For example carbon monoxide emissions from small scale wood combustion are two fold compared to that of energy production in power plants. Methane emission is of the same order as emission from transportation and seven fold compared with those of energy production. Emissions from small heating appliances can be reduced by developing the combustion techniques, but also by using other means, for example catalytic converters. In certain stages of the batch combustion, temperature is not high enough, gas mixing is not good enough and residence time is too short for complete combustion. When placed to a suitable place inside a heating appliance, a catalytic converter can oxidize unburned gases in the flue gas into compounds that are not harmful to the environment. (3 refs.)

  11. Advanced technology application for combustion chamber concepts

    Science.gov (United States)

    Tygielski, Kathy S.

    1992-01-01

    NASA-Marshall is engaged in the development of an Advanced Main Combustion Chamber under the aegis of the Earth-to-Orbit Propulsion Technology Program. AMCC is to be a robust and highly reliable combustion-chamber prototype costing one-third as much as current designs of comparable performance; it will be associated with a reduction of fabrication time by one-half. Attention is presently given to the three component-manufacturing processes used: single-piece investment casting for the structural jacket and manifolds; vacuum plasma spraying, for the combustion liner, and an alternative, platelet-compounded liner.

  12. The John Zink Hamworthy combustion handbook

    CERN Document Server

    Baukal, Charles E

    2013-01-01

    Despite the length of time it has been around, its importance, and vast amounts of research, combustion is still far from being completely understood. Issues regarding the environment, cost, and fuel consumption add further complexity, particularly in the process and power generation industries. Dedicated to advancing the art and science of industrial combustion, The John Zink Hamworthy Combustion Handbook, Second Edition: Volume 3 - Applications offers comprehensive, up-to-date coverage of equipment used in the process and power generation industries. Under the leadership of Charles E. Baukal

  13. Annual Report: Advanced Combustion (30 September 2012)

    Energy Technology Data Exchange (ETDEWEB)

    Hawk, Jeffrey [NETL; Richards, George

    2012-09-30

    The Advanced Combustion Project addresses fundamental issues of fire-side and steam-side corrosion and materials performance in oxy-fuel combustion environments and provides an integrated approach into understanding the environmental and mechanical behavior such that environmental degradation can be ameliorated and long-term microstructural stability, and thus, mechanical performance can lead to longer lasting components and extended power plant life. The technical tasks of this effort are Oxy-combustion Environment Characterization, Alloy Modeling and Life Prediction, and Alloy Manufacturing and Process Development.

  14. Modeling of combustion noise in helicopter engines

    OpenAIRE

    Livebardon, Thomas

    2015-01-01

    The growth of air traffic at the vicinity of areas at high population density imposes to make quieter aircrafts on aeronautical manufacturers.The engine noise is one of the major contributors to the overall sound levels. Furthermore, the combustion is known to be responsible for a broadband noise generation at low-frequency. The combustion noise can be put into two main mechanisms. The first one is the emission of sound pulses by the unsteady heat release of the combustion process and is call...

  15. Characteristic of combustion of Colombian gases

    International Nuclear Information System (INIS)

    Gil B, Edison; Maya, Ruben; Andres, Amel A.

    1996-01-01

    The variety of gas locations in the country, makes that the gas that will be distributed by the net of present gas pipeline a very different composition, what bears to that these they behave in a different way during its use. In this work the main characteristics of the combustion are calculated for the Colombian gases, basically the properties of the combustion and the characteristics of the smoke, as basic information for the design and operation of the gas teams and their certification. These properties were calculated with the special help software for combustion developed by the authors

  16. 3rd International Conference on Numerical Combustion

    CERN Document Server

    Larrouturou, Bernard; Numerical Combustion

    1989-01-01

    Interest in numerical combustion is growing among applied mathematicians, physicists, chemists, engine manufacturers and many industrialists. This proceedings volume contains nine invited lectures and twenty seven contributions carefully selected by the editors. The major themes are numerical simulation of transsonic and supersonic combustion phenomena, the study of supersonic reacting mixing layers, and turbulent combustion. Emphasis is laid on hyperbolic models and on numerical simulations of hydrocarbon planes with a complete set of chemical reactions carried out in two-dimensional geometries as well as on complex reactive flow simulations.

  17. Oxy-fuel combustion of solid fuels

    DEFF Research Database (Denmark)

    Toftegaard, Maja Bøg; Brix, Jacob; Jensen, Peter Arendt

    2010-01-01

    temperature. The flue gas produced thus consists primarily of carbon dioxide and water. Much research on the different aspects of an oxy-fuel power plant has been performed during the last decade. Focus has mainly been on retrofits of existing pulverized-coal-fired power plant units. Green-field plants which......Oxy-fuel combustion is suggested as one of the possible, promising technologies for capturing CO2 from power plants. The concept of oxy-fuel combustion is removal of nitrogen from the oxidizer to carry out the combustion process in oxygen and, in most concepts, recycled flue gas to lower the flame...

  18. Flammability characteristics of combustible gases and vapors

    Energy Technology Data Exchange (ETDEWEB)

    Zabetakis, M. G. [Bureau of Mines, Pittsburgh, PA (United States)

    1964-05-01

    This is a summary of the available limit of flammability, autoignition and burning-rate data for more than 200 combustible gases and vapors in air and other oxidants, as well as of empirical rules and graphs that can be used to predict similar data for thousands of other combustibles under a variety of environmental conditions. Spec$c data are presented on the paraffinic, unsaturated, aromatic, and alicyclic hydrocarbons, alcohols, ethers, aldehydes, ketones, and sulfur compounds, and an assortment of fuels, fuel blends, hydraulic fluids, engine oils, and miscellaneous combustible gases and vapors.

  19. Plasma assisted combustion of parafin mixture

    International Nuclear Information System (INIS)

    Nedybaliuk, O.A.; Chernyak, V.Ya.; Martysh, E.V.; Lisitchenko, T.E.; Vergun, O.Yu.; Orlovska, S.G.

    2013-01-01

    In this work the results of solid paraffin combustion with the aid of the plasma of transverse and rotational gliding arc studies are represented. The question of the additional activation of paraffin based solid fuels is examined. The mixture of n-paraffin and stearin in the solid state as the model of the solid paraffin based fuel is used. The plasma assisted combustion of this model is experimentally investigated. The voltage-current characteristics of discharge at the different regimes are measured. The population temperatures of excited rotational levels are determined. The flame temperature during the combustion of solid paraffin containing mixture is calculated

  20. Stereoscopic pyrometer for char combustion characterization.

    Science.gov (United States)

    Schiemann, M; Vorobiev, N; Scherer, V

    2015-02-10

    For many pulverized fuels, especially coal and biomass, char combustion is the time determining step. Based on intensified ICCD cameras, a novel setup has been developed to study pulverized fuel combustion, mainly in a laminar flow reactor. For char burning characterization, the typical measurement parameters are particle temperature, size, and velocity. The working principle of the camera setup is introduced and its capabilities are discussed by examination of coal particle combustion under CO(2)-enriched, so-called oxy-fuel atmospheres with varying O(2) content.

  1. Novel combustion concepts for sustainable energy development

    CERN Document Server

    Agarwal, Avinash K; Gupta, Ashwani K; Aggarwal, Suresh K; Kushari, Abhijit

    2014-01-01

    This book comprises research studies of novel work on combustion for sustainable energy development. It offers an insight into a few viable novel technologies for improved, efficient and sustainable utilization of combustion-based energy production using both fossil and bio fuels. Special emphasis is placed on micro-scale combustion systems that offer new challenges and opportunities. The book is divided into five sections, with chapters from 3-4 leading experts forming the core of each section. The book should prove useful to a variety of readers, including students, researchers, and professionals.

  2. Chaotic combustion in spark ignition engines

    International Nuclear Information System (INIS)

    Wendeker, Miroslaw; Czarnigowski, Jacek; Litak, Grzegorz; Szabelski, Kazimierz

    2003-01-01

    We analyse the combustion process in a spark ignition engine using the experimental data of an internal pressure during the combustion process and show that the system can be driven to chaotic behaviour. Our conclusion is based on the observation of unperiodicity in the time series, suitable stroboscopic maps and a complex structure of a reconstructed strange attractor. This analysis can explain that in some circumstances the level of noise in spark ignition engines increases considerably due to nonlinear dynamics of a combustion process

  3. Évaluation des pratiques agricoles des légumes feuilles : le cas des ...

    African Journals Online (AJOL)

    SARAH

    30 sept. 2017 ... sont le barrage, les puits à faible profondeur (1 à 2 m) et les tranchées creusées dans la cuvette par les maraîchers. 22 % des producteurs utilisent l'eau du barrage directement, 60 % l'eau des puits (figure 2) uniquement et 18 % utilisent les deux types de ressources (figure 3). Toutes les cultures en saison ...

  4. Étude des caractéristiques des peuplements et des noix de Cocos ...

    African Journals Online (AJOL)

    Cocos nucifera est l'un des arbres cultivés le plus répandu. Il se propage par graine avec un long cycle biologique. Cette étude qui avait pour objectif de caractériser les populations naturelles de cocotiers des Niayes (Sénégal), notamment leur structure et leur fruit, a montré que les arbres sont âgés et leur régénération ...

  5. L'accumulation des métaux lourds au niveau des cultures : Cas des ...

    African Journals Online (AJOL)

    Le Bassin de Sebou présente une importance socio-économique pour le Maroc. En effet, il est sujet de diverses utilisations ; eau potable, eau d'irrigation et eau industrielle. Toutefois, ce bassin subit des pressions multiples, notamment par la pollution métallique. Considérant le risque de bioaccumulation des métaux par ...

  6. Development and testing of the EDF-2 reactor fuel element; Essais et mise au point de l'element combustible pour le reacteur EDF-2

    Energy Technology Data Exchange (ETDEWEB)

    Delpeyroux, P. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Furhmann, R. [Societe Industrielle de Combustible Nucleaire (France)

    1964-07-01

    rassemble les etudes qui ont ete necessaires pour mener a bien la definition de l'element combustible EdF 2. Apres un bref rappel des caracteristiques du reacteur EdF 2 et des options preliminaires ayant permis de fixer un avant-projet d'element combustible, on aborde les etudes proprement dites: - Etudes uranium: essais de passage d'une couronne interne du tube en phase {beta}, flechage du tube sous l'action d'une force concentree, soudage des pastilles d'extremites et verification de leur etancheite. La tenue du tube a l'ecrasement et la resistance des pastilles a l'enfoncement sous l'action de la pression externe sont etudiees en detail dans un autre rapport CEA - Etudes gaine: rappel des conditions de fabrication et verification de l'etancheite de la gaine, tenue des ailettes au fluage sous l'action du courant gazeux - Etudes d'extremites: fluage en compression et soudage des bouchons a la gaine. - Etudes cartouche: determination des caracteristiques des gorges d'ancrage gaine-combustible et des conditions de gainage, verification de la tenue au cyclage thermique de l'element combustible, determination de la chute de temperature au contact gaine-combustible traitee en detail dans un autre rapport CEA, - Etudes de l'ensemble: les etudes se rapportant a la chemise de graphite, au support et aux vibrations de la cartouche ont ete traitees par le service des Etudes Mecaniques et Thermiques (Section de Mecanique), Dans ce domaine, la Section d'Etude d'Elements Combustibles a etudie la tenue des centreurs sous l'action du courant gazeux. L'aboutissement des etudes est constitue par le dessin de l'element combustible, le schema de fabrication et les normes de fabrication. La validite de l'ensemble de ces essais hors pile sera confirmee par des assais en pile qui sont en cours et par l'irradiation des elements dans le reacteur EdF 2 lui-meme. En conclusion, on donne l

  7. 14 CFR 23.859 - Combustion heater fire protection.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Combustion heater fire protection. 23.859... Construction Fire Protection § 23.859 Combustion heater fire protection. (a) Combustion heater fire regions. The following combustion heater fire regions must be protected from fire in accordance with the...

  8. Key factors of combustion from kinetics to gas dynamics

    CERN Document Server

    Rubtsov, Nikolai M

    2017-01-01

    This book summarizes the main advances in the mechanisms of combustion processes. It focuses on the analysis of kinetic mechanisms of gas combustion processes and experimental investigation into the interrelation of kinetics and gas dynamics in gas combustion. The book is complimentary to the one previously published, The Modes of Gaseous Combustion.

  9. Pulse combustion: an assessment of opportunities for increased efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Brenchley, D.L.; Bomelburg, H.J.

    1984-12-01

    The results of a literature review on pulse combustion are discussed. Current, near-future, and potential opportunities for pulse combustion applications are summarized, and the barriers to developing and using pulse combustion technology are discussed, along with research and development needs. Also provided are the proceedings of a pulse combustion workshop held in May, 1984 in Seattle, Washington. (LEW)

  10. Combustion Noise Analysis for Combustion and Fuels Diagnosis of a CI Diesel Engine Operating with Biodiesels

    OpenAIRE

    Zhen, Dong; Shi, Zhanqun; Song, Zhongyue; Gu, Fengshou; Ball, Andrew

    2015-01-01

    In this paper, the combustion noise of a compression ignition (CI) diesel engine operating with biodiesels has been investigated experimentally. It aims to explore an effective method for combustion process monitoring and fuel quality evaluation through analysing the characteristics of the engine combustion noise. The experiments were conducted on a four-cylinder, four-stroke, direct injection and turbocharged diesel engine fuelled with biodiesels (B50 and B100) and normal pure diesel, and op...

  11. Coal Combustion Products Extension Program

    Energy Technology Data Exchange (ETDEWEB)

    Tarunjit S. Butalia; William E. Wolfe

    2006-01-11

    This final project report presents the activities and accomplishments of the ''Coal Combustion Products Extension Program'' conducted at The Ohio State University from August 1, 2000 to June 30, 2005 to advance the beneficial uses of coal combustion products (CCPs) in highway and construction, mine reclamation, agricultural, and manufacturing sectors. The objective of this technology transfer/research program at The Ohio State University was to promote the increased use of Ohio CCPs (fly ash, FGD material, bottom ash, and boiler slag) in applications that are technically sound, environmentally benign, and commercially competitive. The project objective was accomplished by housing the CCP Extension Program within The Ohio State University College of Engineering with support from the university Extension Service and The Ohio State University Research Foundation. Dr. Tarunjit S. Butalia, an internationally reputed CCP expert and registered professional engineer, was the program coordinator. The program coordinator acted as liaison among CCP stakeholders in the state, produced information sheets, provided expertise in the field to those who desired it, sponsored and co-sponsored seminars, meetings, and speaking at these events, and generally worked to promote knowledge about the productive and proper application of CCPs as useful raw materials. The major accomplishments of the program were: (1) Increase in FGD material utilization rate from 8% in 1997 to more than 20% in 2005, and an increase in overall CCP utilization rate of 21% in 1997 to just under 30% in 2005 for the State of Ohio. (2) Recognition as a ''voice of trust'' among Ohio and national CCP stakeholders (particularly regulatory agencies). (3) Establishment of a national and international reputation, especially for the use of FGD materials and fly ash in construction applications. It is recommended that to increase Ohio's CCP utilization rate from 30% in 2005 to

  12. Poissons Characoïdes des Guyanes. I. Généralités. II. Famille des Serrasalmidae

    NARCIS (Netherlands)

    Géry, J.

    1972-01-01

    TABLE DES MATIÈ RES ENGLISH PREFACE AND SUMMARY......... 5 AVANT-PROPOS................. 8 RESUME ................... 9 PREMIERE PARTIE : GENERALITES SUR LES GUYANES ET LES POISSONS CHARACOÏDES................. 12 Chapitre 1. Introduction 1-1. Historique.................. 12 1- 2. Sources et

  13. Onlinespieler abseits des Mainstreams

    Directory of Open Access Journals (Sweden)

    Harald Baumgartlinger

    2012-12-01

    Full Text Available MMO(RPGs „Massively Multiplayer Online (Role-Playing Games“ nehmen einen Sonderstatus unter den Onlinespielen ein, welcher durch den wachsenden wirtschaftlichen Erfolg, insbesondere durch den „breakthrough hit“ (Duchenaut et al. 2006: 407 World of Warcraft (WoW, auch an Bedeutung für die Medien- und Kommunikationswissenschaft gewinnt (vgl. Inderst 2009: 15; vgl. Seifert/Jöckel 2008: 297. Der Primus des Genres, WoW, repräsentiert gemeinsam mit einigen nahezu identen Titeln insgesamt 85 Prozent der gespielten MMOGs (vgl. Williams et al. 2008: 999. Daher befasst sich auch die Mehrheit der vorliegenden Studien mit eben diesen Spielen. Neue Formen von MMO(Gs können jedoch zu ebenso neuartigen Spielerfahrungen führen und damit unterschiedliche Nutzungsmotive befriedigen (vgl. Seifert/Jöckel 2008: 309 und folglich zu einem gänzlich anderen Spielerleben führen. Während im Mainstream die kooperativen Spielerbeziehungen überwiegen, dominiert in Darkfall Online der soziale Wettbewerb. Der von Williams et al. 2008 verwendete Fragebogen diente als Rohling für die Kreation eines für die speziellen Anforderungen adaptierten Erhebungstools zur Erforschung der Spielertypologie und der Motive der Darkfall-Online-SpielerInnen. Die in der Onlinebefragung (N = 506 gesammelten Daten belegen, dass sich sowohl die Spielerdemographie, als auch die Motive der Spieler von den Mainstream MMOs unterscheiden. Zudem konnten realweltliche Eigenschaften der Spieler als signifikante Einflussfaktoren für die Spielzuwendung identifiziert werden.

  14. Terre des hommes

    CERN Multimedia

    Staff Association

    2012-01-01

    Transformez votre téléphone portable en geste de solidarité ! Collecte du 12 au 23 novembre 2012   Faites un geste simple et utile en déposant vos téléphones portables inutilisés dans les urnes installées dans les trois restaurants du CERN. En Suisse, une personne change tous les 12 à 18 mois de téléphone portable. La plupart de nos vieux appareils sont simplement laissés à l’abandon avec comme seule fonction de parer une éventuelle panne à venir. On  estime ainsi que 8 millions de portables sont inutilisés, alors qu'entre 30 et 50% peuvent être réutilisés. L'action Solidarcomm leur offre une deuxième vie ! Terre des Hommes Suisse, dans le cadre de la campagne Solidarcomm, collecte et valorise vos téléphones inutilis&...

  15. DIAGNOSIS OF FAILURE OF COMBUSTION IN THE COMBUSTION CHAMBER WITH A THERMOVISION EQUIPMENT

    Directory of Open Access Journals (Sweden)

    S. V. Vorobiev

    2014-01-01

    Full Text Available The use of thermovision technology to diagnose failure of the combustion flame test tube of the main combustion chamber gas turbine engine is deal with in the article. Join the thermal radiation of the jet of combustion products and the internal elements was carried out using short-wave thermovision system AGA-782 with spectral spectral filters in several ranges from 3.2 to 5.6 microns. Thermovision is mounted on the axis of the flame tube. The output signal was recorded and processed on a computer in real time, allowing monitor the combustion process and the thermal state of the object during the experiment.

  16. Engine combustion control via fuel reactivity stratification

    Science.gov (United States)

    Reitz, Rolf Deneys; Hanson, Reed M; Splitter, Derek A; Kokjohn, Sage L

    2013-12-31

    A compression ignition engine uses two or more fuel charges having two or more reactivities to control the timing and duration of combustion. In a preferred implementation, a lower-reactivity fuel charge is injected or otherwise introduced into the combustion chamber, preferably sufficiently early that it becomes at least substantially homogeneously dispersed within the chamber before a subsequent injection is made. One or more subsequent injections of higher-reactivity fuel charges are then made, and these preferably distribute the higher-reactivity matter within the lower-reactivity chamber space such that combustion begins in the higher-reactivity regions, and with the lower-reactivity regions following thereafter. By appropriately choose the reactivities of the charges, their relative amounts, and their timing, combustion can be tailored to achieve optimal power output (and thus fuel efficiency), at controlled temperatures (and thus controlled NOx), and with controlled equivalence ratios (and thus controlled soot).

  17. Flex-flame burner and combustion method

    Science.gov (United States)

    Soupos, Vasilios; Zelepouga, Serguei; Rue, David M.; Abbasi, Hamid A.

    2010-08-24

    A combustion method and apparatus which produce a hybrid flame for heating metals and metal alloys, which hybrid flame has the characteristic of having an oxidant-lean portion proximate the metal or metal alloy and having an oxidant-rich portion disposed above the oxidant lean portion. This hybrid flame is produced by introducing fuel and primary combustion oxidant into the furnace chamber containing the metal or metal alloy in a substoichiometric ratio to produce a fuel-rich flame and by introducing a secondary combustion oxidant into the furnace chamber above the fuel-rich flame in a manner whereby mixing of the secondary combustion oxidant with the fuel-rich flame is delayed for a portion of the length of the flame.

  18. Two phase exhaust for internal combustion engine

    Science.gov (United States)

    Vuk, Carl T [Denver, IA

    2011-11-29

    An internal combustion engine having a reciprocating multi cylinder internal combustion engine with multiple valves. At least a pair of exhaust valves are provided and each supply a separate power extraction device. The first exhaust valves connect to a power turbine used to provide additional power to the engine either mechanically or electrically. The flow path from these exhaust valves is smaller in area and volume than a second flow path which is used to deliver products of combustion to a turbocharger turbine. The timing of the exhaust valve events is controlled to produce a higher grade of energy to the power turbine and enhance the ability to extract power from the combustion process.

  19. Mechanism of Combustion of Heterogeneous Solid Propellants

    National Research Council Canada - National Science Library

    Price, E

    1998-01-01

    ... (and compare results with those of AP oxidizer and Ap/hydrocarbon binder propellants). 4. Develop a realistic qualitative model of the combustion process that would identify the requirements for formulation of realistic analytical models.

  20. Plume Diagnostics for Combustion Stability Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Sierra Engineering Inc. and Purdue University propose to develop a non-intrusive plume instrument capable of detecting and diagnosing combustion instability. This...

  1. System and method for engine combustion

    Energy Technology Data Exchange (ETDEWEB)

    Sczomak, David P.; Gallon, Robert J.; Solomon, Arun S.

    2018-03-13

    A combustion system for use with one or more cylinder bores of an internal combustion engine includes at least one cylinder head defining first and second intake ports in fluid communication with the one or more cylinder bores. A flap is adjustably connected to the at least one cylinder head. The flap includes a first flap portion cooperating with the first intake port extending from an arm and a second flap portion cooperating with the second intake port extending from the arm and disposed adjacent the first flap portion. A controller in electrical communication with an actuator monitors the condition of the engine and actuates the flap to position the first and second flap portions between first and second positions to create a first combustion condition and a second combustion condition.

  2. Fuels Combustion Research: Supercritical Fuel Pyrolysis

    National Research Council Canada - National Science Library

    Glassman, Irvin

    2001-01-01

    .... The focus during the subject period was directed to understanding the pyrolysis and combustion of endothermic fuels under subcritical conditions and the pyrolysis of these fuels under supercritical conditions...

  3. Fuels Combustion Research: Supercritical Fuel Pyrolysis

    National Research Council Canada - National Science Library

    Glassman, Irvin

    2000-01-01

    .... The focus during the subject period was directed to understanding the pyrolysis and combustion of endothermic fuels under subcritical conditions and the pyrolysis of these fuels under supercritical conditions...

  4. Explosion-combustion in exoplanetary atmospheres

    Science.gov (United States)

    Grenfell, John Lee; Godolt, Mareike; Stracke, Barbara; Gebauer, Stefanie; Rauer, Heike

    2017-04-01

    Conditions leading to explosion or/and combustion in exoplanetary atmospheres are investigated for different atmospheric composition, temperature and pressure. Cases considered are Super-Earths orbiting in the habitable zone of M-dwarf stars with atmospheres consisting of abiotically-produced molecular oxygen together with molecular hydrogen accreted from the protoplanetary disk. Should these atmospheres undergo hydrogen-oxygen combustion triggered by e.g. lightning or cosmic rays, this would limit the build-up of abiotic oxygen, lower the hydrogen gas envelope and could lead to liquid oceans with masses tens to hundreds of times larger than on the Earth. We also consider other explosive-combustive gas mixtures which could lead to carbon monoxide or methane combustion in the atmospheres of some Mini Gas Planets or in (Early) Earth-like atmospheres.

  5. Recoupement des politiques: renforcer les initiatives de reddition de ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Au cours des dernières années, les acquisitions massives (achats, locations ou autres arrangements) de terres agricoles dans les pays en développement par des particuliers, des entreprises et des gouvernements étrangers ont eu des effets économiques positifs tout comme des effets négatifs sur les moyens de ...

  6. 107 Etude des facteurs de variation des prix d'intérêt des matières ...

    African Journals Online (AJOL)

    DELL

    Imen BELHADJ SLIMEN et Taha NAJAR. Etude des facteurs de variation des prix d'intérêt des matières premières de substitution utilisées dans les aliments concentrés des animaux d'élevage. Imen BELHADJ SLIMEN1,2* et Taha NAJAR1,2. 1Institut National Agronomique de Tunisie, Département Ressources Animales, ...

  7. Secondary combustion system for woodburning stove

    Energy Technology Data Exchange (ETDEWEB)

    von Conta, P. E. W.

    1985-11-19

    A secondary combustion system for a woodburning stove employs a concave shaped screen for dispersing exhaust gases. A mixing chamber is formed in an insulated conduit between the concave screen and a second planar screen. The planar screen is perforated to form a random array of flaps which increase the turbulence of the exhaust stream so that a secondary combustion of the exhaust gases is produced.

  8. COMBUSTION OPTIMIZATION IN SPARK IGNITION ENGINES

    OpenAIRE

    Barhm Mohamad; Gabor Szebesi; Betti Bollo

    2017-01-01

    The blending technique used in internal combustion engines can reduce emission of toxic exhaust components and noises, enhance overall energy efficiency and reduce fuel costs. The aim of the study was to compare the effects of dual alcohols (methanol and ethanol) blended in gasoline fuel (GF) against performance, combustion and emission characteristics. Problems arise in the fuel delivery system when using the highly volatile methanol - gasoline blends. This problem is reduced by using specia...

  9. Building America Expert Meeting. Combustion Safety

    Energy Technology Data Exchange (ETDEWEB)

    Brand, Larry [Partnership for Advanced Residential Retrofit (PARR), Des Plaines, IL (United States)

    2013-03-01

    This is an overview of "The Best Approach to Combustion Safety in a Direct Vent World," held June 28, 2012, in San Antonio, TX. The objective of this Expert Meeting was to identify gaps and barriers that need to be addressed by future research, and to develop data-driven technical recommendations for code updates so that a common approach for combustion safety can be adopted by all members of the building energy efficiency and code communities.

  10. Building America Expert Meeting: Combustion Safety

    Energy Technology Data Exchange (ETDEWEB)

    Brand, L.

    2013-03-01

    This is a meeting overview of 'The Best Approach to Combustion Safety in a Direct Vent World', held June 28, 2012, in San Antonio, Texas. The objective of this Expert Meeting was to identify gaps and barriers that need to be addressed by future research, and to develop data-driven technical recommendations for code updates so that a common approach for combustion safety can be adopted by all members of the building energy efficiency and code communities.

  11. Simulation of lean premixed turbulent combustion

    OpenAIRE

    Bell, John B.; Day, Marcus S.; Almgren, Ann S.; Lijewski, Michael J.; Rendleman, Charles A.; Cheng, Robert K.; Shepherd, Ian G.

    2008-01-01

    There is considerable technological interest in developing new fuel-flexible combustion systems that can burn fuels such as hydrogenor syngas. Lean premixed systems have the potential to burn these types of fuels with high efficiency and low NOx emissions due to reduced burnt gas temperatures. Although traditional scientific approaches based on theory and laboratory experiment have played essential roles in developing our current understanding of premixed combustion, they are unable to m...

  12. Internal combustion engine and method for control

    Science.gov (United States)

    Brennan, Daniel G

    2013-05-21

    In one exemplary embodiment of the invention an internal combustion engine includes a piston disposed in a cylinder, a valve configured to control flow of air into the cylinder and an actuator coupled to the valve to control a position of the valve. The internal combustion engine also includes a controller coupled to the actuator, wherein the controller is configured to close the valve when an uncontrolled condition for the internal engine is determined.

  13. LES and RANS modeling of pulverized coal combustion in swirl burner for air and oxy-combustion technologies

    International Nuclear Information System (INIS)

    Warzecha, Piotr; Boguslawski, Andrzej

    2014-01-01

    Combustion of pulverized coal in oxy-combustion technology is one of the effective ways to reduce the emission of greenhouse gases into the atmosphere. The process of transition from conventional combustion in air to the oxy-combustion technology, however, requires a thorough investigations of the phenomena occurring during the combustion process, that can be greatly supported by numerical modeling. The paper presents the results of numerical simulations of pulverized coal combustion process in swirl burner using RANS (Reynolds-averaged Navier–Stokes equations) and LES (large Eddy simulation) methods for turbulent flow. Numerical simulations have been performed for the oxyfuel test facility located at the Institute of Heat and Mass Transfer at RWTH Aachen University. Detailed analysis of the flow field inside the combustion chamber for cold flow and for the flow with combustion using different numerical methods for turbulent flows have been done. Comparison of the air and oxy-coal combustion process for pulverized coal shows significant differences in temperature, especially close to the burner exit. Additionally the influence of the combustion model on the results has been shown for oxy-combustion test case. - Highlights: • Oxy-coal combustion has been modeled for test facility operating at low oxygen ratio. • Coal combustion process has been modeled with simplified combustion models. • Comparison of oxy and air combustion process of pulverized coal has been done. • RANS (Reynolds-averaged Navier–Stokes equations) and LES (large Eddy simulation) results for pulverized coal combustion process have been compared

  14. Gyrodactylidae et Gyrodactylose des Salmonidae

    Directory of Open Access Journals (Sweden)

    MALMBERG G.

    1993-01-01

    Full Text Available Vingt et une espèces de Gyrodactylus de Salmonidae arrangées en six groupes sont présentées. Les observations concernant ces espèces dans les milieux naturels et en pisciculture sont résumées. Sur la base de données générales relatives aux espèces de Gyrodactylus en milieu naturel en Scandinavie et Baltique, les observations biologiques, écologiques et comportementales de G. salaris Malmberg, 1957 et G. derjavini MALMBERG et MALMBERG (1987 des salmonidae sauvages des rivières norvégiennes et suédoises sont présentées. La viviparité unique, la reproduction asexuée et sexuée et le pouvoir de reproduction chez les Gyrodactylus sont développés. La Gyrodactylose à G. salaris est abordée en milieu naturel, dans les rivières norvégiennes et en pisciculture, en Suède et au Danemark. L'étude ultrastructurale des blessures causées par G. salaris ainsi que les résultats expérimentaux sur les espèces norvégiennes et canadiennes sont présentés. La distribution géographique naturelle des Salmonidae, les modifications liées à l'homme et à l'activité économique ainsi que les Salmonidae élevés sont revus. La présence de six groupes d'espèces de Gyrodactylus en Amérique du Nord et Eurasie est discutée en fonction de la distribution géographique des espèces hôtes. Il est souligné qu'une propagation intercontinentale des espèces de Gyrodactylus de Salmonidae a dû être impossible à cause de leur origine limnique d'une part et de la salinité élevée des océans atlantique et pacifique d'autre part. Les exigences micro et macro environnementales des espèces sont discutées dans les conditions naturelles et les variations saisonnières, préférendums et tolérances du parasitisme sont signalés. L'effet des conditions de pisciculture sur les espèces de Gyrocactylus sont discutées : la capacité reproductrice et de propagation ainsi que la spécificité — stricte dans la nature — peuvent être influenc

  15. Simulations of a Circulating Fluidized Bed Chemical Looping Combustion System Utilizing Gaseous Fuel Simulation de la combustion en boucle chimique d’une charge gazeuse dans un lit fluidisé circulant

    Directory of Open Access Journals (Sweden)

    Mahalatkar K.

    2011-05-01

    Full Text Available Numerical studies using Computational Fluid Dynamics (CFD have been carried out for a complete circulating fluidized bed chemical looping combustor described in the literature (Abad et al., 2006 Fuel 85, 1174-1185. There have been extensive experimental studies in Chemical Looping Combustion (CLC, however CFD simulations of this concept are quite limited. The CLC experiments that were simulated used methane as fuel. A 2-D continuum model was used to describe both the gas and solid phases. Detailed sub-models to account for fluid-particle and particleparticle interaction forces were included. Global models of fuel and carrier chemistry were utilized. The results obtained from CFD were compared with experimental outlet species concentrations, solid circulation rates, solid mass distribution in the reactors, and leakage and dilution rates. The transient CFD simulations provided a reasonable match with the reported experimental data. Des études numériques de simulation des écoulements (CFD ont été réalisées sur un lit fluidisé circulant opérant en combustion par boucle chimique (CLC décrit dans la littérature (Abad et al., 2006 Fuel 85, 1174-1185. Si de nombreuses études expérimentales ont été conduites pour étudier le procédé CLC, les études concernant la simulation des écoulements par CFD de ce concept sont très limitées. Le système de combustion en boucle chimique simulé dans cette étude concerne la combustion d’une charge gazeuse (méthane. Un modèle 2-D à deux phases continues a été utilisé pour décrire les phases gaz et solide avec des sous-modèles détaillés pour décrire les forces d’interactions entre fluideparticule et particule-particule. Des modèles cinétiques globaux ont été intégrés pour décrire les réactions de combustion et de transformation du matériau transporteur d’oxygène. Les résultats obtenus par CFD ont été comparés aux concentrations expérimentales mesurées des diff

  16. Réduction de l'oxyde d'azote par la suie dans les produits de combustion Reduction of Nitric Oxyde by Soot in Combustion Products

    Directory of Open Access Journals (Sweden)

    De Soete G.

    2006-11-01

    Full Text Available On a étudié dans un réacteur à lit fixe la réduction du NO par de la suie formée dans des flammes riches de mélanges éthane/oxygène/argon. Le mélange gazeux traversant le réacteur est de l'argon dopé avec du NO; dans certains cas ce mélange est enrichi d'hydrogène ou d'oxyde de carbone. En présence d'hydrogène ou d'oxyde de carbone, ces vitesses sont nettement plus grandes qu'avec la suie seule. La comparaison avec des vitesses réactionnelles obtenues sur des lits fixes composés d'autres matériaux solides, tels que l'alumine, montre que la réduction de l'oxyde d'azote se fait principalement par une réaction hétérogène avec l'hydrogène et l'oxyde de carbone catalysée par la suie. D'autres matériaux solides,tels que des oxydes réfractaires présentent une activité catalylique aussi importante que la suie. Cette observation fournit une nouvelle explication de l'effet connu de certains additifs sur la réduction de NO dans les flammes. Dans la seconde partie de l'étude, on mesure la réduction des oxydes d'azote dans les flammes fuligineuses de prémélange. De l'argon dopé par de l'oxyde d'azote est injecté dans les produits de combustion de ces flammes chargés de suie; l'introduction du NO est faite à différentes distances derrière le brûleur, correspondant à différents niveaux de température des produits de combustion. La réduction fractionnelle des oxydes d'azote est mesurée en fonction de la concentration en suie, en hydrogène et en oxyde de carbone, en faisant varier la composition du mélange inflammable. Les résultats expérimentaux sont en bon accord avec la réduction calculée en se basant sur les informations cinétiques obtenues en lit fixe. The kinetics of nitric oxide réduction by soot collected from hydrocarbon flames is studied in a fixed-bed reactor. The gas flow traversing thé reactor is either argon with NO, or argon with hydrogen and NO, or argon with carbon monoxide and NO. In th

  17. Combustion kinetics and reaction pathways

    Energy Technology Data Exchange (ETDEWEB)

    Klemm, R.B.; Sutherland, J.W. [Brookhaven National Laboratory, Upton, NY (United States)

    1993-12-01

    This project is focused on the fundamental chemistry of combustion. The overall objectives are to determine rate constants for elementary reactions and to elucidate the pathways of multichannel reactions. A multitechnique approach that features three independent experiments provides unique capabilities in performing reliable kinetic measurements over an exceptionally wide range in temperature, 300 to 2500 K. Recent kinetic work has focused on experimental studies and theoretical calculations of the methane dissociation system (CH{sub 4} + Ar {yields} CH{sub 3} + H + Ar and H + CH{sub 4} {yields} CH{sub 3} + H{sub 2}). Additionally, a discharge flow-photoionization mass spectrometer (DF-PIMS) experiment is used to determine branching fractions for multichannel reactions and to measure ionization thresholds of free radicals. Thus, these photoionization experiments generate data that are relevant to both reaction pathways studies (reaction dynamics) and fundamental thermochemical research. Two distinct advantages of performing PIMS with high intensity, tunable vacuum ultraviolet light at the National Synchrotron Light Source are high detection sensitivity and exceptional selectivity in monitoring radical species.

  18. Carburetor for internal combustion engines

    Science.gov (United States)

    Csonka, John J.; Csonka, Albert B.

    1978-01-01

    A carburetor for internal combustion engines having a housing including a generally discoidal wall and a hub extending axially from the central portion thereof, an air valve having a relatively flat radially extending surface directed toward and concentric with said discoidal wall and with a central conoidal portion having its apex directed toward the interior of said hub portion. The housing wall and the radially extending surface of the valve define an air passage converging radially inwardly to form an annular valving construction and thence diverge into the interior of said hub. The hub includes an annular fuel passage terminating at its upper end in a circumferential series of micro-passages for directing liquid fuel uniformly distributed into said air passage substantially at said valving constriction at right angles to the direction of air flow. The air valve is adjustable axially toward and away from the discoidal wall of the carburetor housing to regulate the volume of air drawn into the engine with which said carburetor is associated. Fuel is delivered under pressure to the fuel metering valve and from there through said micro-passages and controlled cams simultaneously regulate the axial adjustment of said air valve and the rate of delivery of fuel through said micro-passages according to a predetermined ratio pattern. A third jointly controlled cam simultaneously regulates the ignition timing in accordance with various air and fuel supply settings. The air valve, fuel supply and ignition timing settings are all independent of the existing degree of engine vacuum.

  19. Fuel and Combustion Characteristics of Organic Wastes

    Science.gov (United States)

    Namba, Kunihiko; Ida, Tamio

    From a viewpoint of environmental preservation and resource protection, the recycling of wastes has been promoting. Expectations to new energy resource are growing by decrease of fossil fuel. Biomass is one of new energies for prevent global warning. This study is an attempt to burn biomass lamps made from residues in order to thermally recycle waste products of drink industries. The pyrolytic properties of shochu dregs and used tea leaves were observed by thermo-gravimertic analysis (TG) to obtained fundamental data of drink waste pyrolysis. It observed that shochu dregs pyrolyze under lower temperature than used tea leaves. These wastes were compressed by hot press apparatus in the temperature range from 140 to 180 °C for use as Bio-fuel (BF). The combustion behavior of BF was observed in fall-type electric furnace, where video-recording was carried out at sequential steps, such as ignition, visible envelope flame combustion and char combustion to obtain combustion characteristics such as ignition delay, visible flame combustion time and char combustion time.

  20. Fluidized bed combustion: mixing and pollutant limitation

    Energy Technology Data Exchange (ETDEWEB)

    Leckner, B. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Energy Conversion

    1997-10-01

    Fluidized bed combustion (FBC) has been applied commercially during a few decades, and sufficient knowledge is gained to design boilers with sizes of up to several hundreds of megawatt thermal power (MW{sub th}). The knowledge of what goes on inside a large combustion chamber is still limited, however, and this impedes further optimization and efficient solution of problems that might occur. Despite this lack of knowledge the present survey deals with combustion chamber processes and discusses mixing and distribution of fuel and air in the combustion chamber and its importance for sulphur capture and reduction of emissions of nitrogen oxides. It is desirable to present the material in a general way and to cover the entire field of FBC. However, the scarce openly published information deals mostly with coal combustion in atmospheric circulating fluidized bed (CFB) combustors, and therefore this application will receive most attention, but reference is also made to pressurized combustion and to other fuels than coal. In this context the important work made in the LIEKKI project on the analysis of different fuels and on the influence of pressure should be especially pointed out. (orig.)

  1. Promouvoir l'inclusion économique des jeunes et des femmes par l ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    entrepreneuriat à Madagascar. Le projet vise à promouvoir l'entrepreneuriat des femmes et des jeunes à Madagascar à travers le renforcement des capacités locales de recherche et des analyses pertinentes et utiles. En particulier les objectifs sont de ...

  2. Contamination des moules ( Mytilus galloprovincialis ) des côtes de ...

    African Journals Online (AJOL)

    Dans ce travail, nous avons etudie la contamination par les Hydrocarbures Aromatiques Polycycliques des moules recoltees au niveau des cotes de la region de Dakar. Les sites ont ete choisis en fonction des activites qui y sont developpees. Lfextraction des HAPs a ete faite au moyen dfun extracteur Soxhlet avec un ...

  3. Taux des lipides et des protéines et composition en acides gras du ...

    African Journals Online (AJOL)

    Taux des lipides et des protéines et composition en acides gras du tissu comestible des crustacés et des mollusques pêchés en Algérie : Effet du halofénozide (RH-0345) sur la composition en acides gras de Penaeus kerathurus (Crustacé, Décapode).

  4. Étude des impacts écologiques du dynamisme spatio-temporel des ...

    African Journals Online (AJOL)

    changement, (iv) élaborer une prospective des changements en 2050 et (v) évaluer les impacts du changement. Le change- ment des habitats naturels s'est déroulé au cours des temps mais il n'a ... assesses the impacts of habitat change on the resident glob- ... La gestion des changements, qui se manifestent presque.

  5. Ostéosynthèse des fractures des métacarpiens et des phalanges de ...

    African Journals Online (AJOL)

    Ostéosynthèse des fractures des métacarpiens et des phalanges de la main par mini plaque: à propos de 12 cas. Erraji Moncef, Derfoufi Abdelhafid, Kharraji Abdessamad, Agoumi Omar, Abdeljaouad Najib, Daoudi Abdelkrim, Yacoubi Hicham ...

  6. Combustion, detonation, shock waves. Proceedings of the Zel'dovich memorial - International conference on combustion. Volume 1

    International Nuclear Information System (INIS)

    Merzhanov, A.G.; Frolov, S.M.

    1995-01-01

    This book contains lectures by the experts in various fields of modern research in combustion, detonation and shock waves, presented at the Zel'dovich memorial - International conference on combustion dedicated to the 80-th birthday of academician Ya.B. Zel'dovich. There are eight chapters discussing the state-of-the-art in combustion kinetics, ignition and steady-state flame propagation, diffusion and heterogeneous combustion, turbulent combustion, unsteady combustion, detonation, combustion and detonation analogies, intense shock waves and extreme states of matter [ru

  7. Thermométrie DRASC appliquée aux milieux en combustion Cars Temperature Measurements in Combustion

    Directory of Open Access Journals (Sweden)

    Bouchardy P.

    2006-11-01

    Full Text Available La diffusion Raman anti-Stokes cohérente (DRASC est devenue une technique de thermométrie aujourd'hui opérationnelle. Après un rappel du principe de la mesure, un montage de DRASC est décrit. Les diverses contraintes auxquelles l'expérimentateur doit faire face sont présentées. Les avantages et les inconvénients des spectroscopies DRASC par balayage et multiplex sont comparés. Deux expériences, l'une dans un écoulement à haute enthalpie, l'autre dans un foyer de simulation de turbomachine, illustrent, par leurs résultats, les performances obtenues ainsi que les difficultés le plus souvent rencontrées. Coherent anti-Stokes Raman diffusion (CARS has now become an operational thermometric technique. After reviewing the principle of the measurement, this article describes a CARS set-up. The different constraints that an experimenter must cope with are described. The advantages and disadvantages of CARS spectroscopy by scanning and multiplexing are compared. The results of two experiments, one in a high-enthalpy flow and the other in a turbojet engine simulation combustion chamber illustrate the performances obtained as well as the difficulties most often encountered.

  8. La convergence des rôles respectifs des relationnistes et des journalistes influence-t-elle la perception qu'ils ont les uns des autres?

    DEFF Research Database (Denmark)

    Valentini, Chiara

    2017-01-01

    la convergence des rôles respectifs des praticiens des relations publiques et des journalistes a un effet favorable sur la perception qu’ils ont les uns des autres. L’effet est plus marqué chez les praticiens des relations publiques, car leur vision de la profession en journalisme correspond à celle...... profession et de celle de leurs contreparties? Comment perçoivent-ils leurs rôles, leurs méthodes de travail et leurs interactions? Nous avons employé une méthode mixte, comprenant des entretiens en personne et des enquêtes en ligne, afin de recueillir et d’analyser les données. Les résultats indiquent que...

  9. Effets des extraits des feuilles de Alchornea cordifolia ...

    African Journals Online (AJOL)

    Faisant suite à deux études préliminaires, le but de cette étude est de rechercher, un effet antioxydant des feuilles de Alchornea cordifolia vis-à-vis du H2O2 relargué par le polynucléaire neutrophile stimulé. Deux extraits ont été préparés à partir des feuilles séchées : un macérât aqueux et un extrait à l'acétate d'éthyle.

  10. Promouvoir l'entrepreneuriat inclusif des jeunes et des femmes ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Un débat d'experts organisé par le CRDI s'attaque au mariage précoce lors du forum sur la condition des femmes à l'ONU. Des chercheurs appuyés par le CRDI parlent de leurs expériences au Comité sur les ONG lors du forum de la Commission de la condition de la femme. Voir davantageUn débat d'experts organisé par ...

  11. Impact des proprietes physicochimiques des sols de culture du ...

    African Journals Online (AJOL)

    La proportion moyenne de spores non-viables (55 %) est élevée. Il a été noté des corrélations positives entre les communautés de CMA et le magnésium (R = 0,65), la CEC (R = 0,69), l'argile (R = 0,74) et le limon grossier (R = 0,79). Par contre des corrélations négatives ont été obtenues avec le sable fin (R = -0,60) et le ...

  12. Evaluation economique des performances des services d'eau ...

    African Journals Online (AJOL)

    Abstract. En Algérie, le recours à des entreprises spécialisées dans la production et la distribution d'eau potable implique la nécessité de disposer d'évaluations du coût de ces activités. Cet article propose une étude micro-économétrique de la fonction de coût de l'alimentation en eau potable sur des données de panel, ...

  13. Evolution des intensites maximales annuelles des pluies horaires ...

    African Journals Online (AJOL)

    Ces résultats ne sont pas suffisants pour établir une relation entre les variations graduelles observées et le phénomène de changement climatique. La complexité du système climatique de l'Afrique de l'Ouest, la variabilité naturelle des données extrêmes et la longueur des séries utilisées suggèrent une prudence en la ...

  14. Evaluation des connaissances des enseignants du secondaire de l ...

    African Journals Online (AJOL)

    Evaluation des connaissances des enseignants du secondaire de l'atlantique au Benin sur les facteurs de risques du cancer du col de l'uterus en 2014. ... Les données ont été collectées à l'aide d'un questionnaire auto-administré. Une régression logistique pas à pas descendante a été faite. L'adéquation du modèle a été ...

  15. Comportement des polluants des eaux pluviales urbaines en ...

    African Journals Online (AJOL)

    C'est dans ce contexte que s'inscrit le présent travail qui porte sur la dégradation des paramètres organiques (DBO5, DCO, MES, O2, NO-3, pH, T, Fer, turbidité) dans différents milieux : naturel (rivière), canal artificiel, rivière (aux rives revêtues). Le traitement des données, effectué sur les trois sites d'observation sur deux ...

  16. Labellisation des miels et valorisation des spécifications régionales ...

    African Journals Online (AJOL)

    régionaux qui pilote les activités dénommé « Plate Forme Miel de Boeny ». Des outils ont été également conçus : des guides, des manuels, des supports de communication permettant de mieux gérer et de contrôles la qualité des miels. Des dispositifs de suivis et de contrôle sont en vue, mais aussi la création des ...

  17. Comparative study of two co-combustion concepts for sewage sludge in coal dust furnaces; Vergleich zweier Mitverbrennungskonzepte fuer Klaerschlamm in Kohlestaubfeuerungen

    Energy Technology Data Exchange (ETDEWEB)

    Spliethoff, H.; Gerhardt, T.; Ruediger, H.; Hein, K.R.G. [Stuttgart Univ. (Germany). Inst. fuer Verfahrenstechnik und Dampfkesselwesen

    1996-12-31

    Processes for thermal use of sewage sludge in coal dust furnaces were investigated at the Institute of Chemical Engineering and Boiler Technology (IVD) of Stuttgart university. Direct co-combustion of sewage sludge in coal dust furnaces is a simple concept, but it is useful provided that co-combustion has no negative effects in terms of performance, emissions and residue disposal. Externally dried sewage sludge has a residual water content in the same range as coal dust. The effects of co-combustion are discussed, and the experimentally determined effect in terms of emissions and residues is presented. Pyrolysis of the sewage sludge and use of the resulting gas as a reduction agent for denitrification may reduce negative effects of co-combustion on performance, emissions and residues.(orig) [Deutsch] Am Institut fuer Verfahrenstechnik und Dampfkesselwesen (IVD) der Universitaet Stuttgart werden an Versuchsanlagen verschiedene Verfahren zur thermischen Nutzung von Klaerschlaemmen in Verbindung mit Kohlenstaufeuerungen untersucht. Die direkte Mitverbrennung von Klaerschlamm in Kohlestaubfeuerungen ist ein einfaches Konzept, das dann sinnvoll ist, wenn die Mitverbrennung keine negativen Auswirkungen auf Betrieb, Emissionen und Verwertung der Rueckstaende mit sich bringt. Bei einer externen Trockung weist der Klaerschlamm einen aehnlichen Wassergehalt wie der Auslegungsbrennstoff von Steinkohlenstaubfeuerungen auf. Die moeglichen Auswirkungen der Mitverbrennung von Klaerschlamm werden diskutiert und der im Versuch ermittelte Einfluss auf Emissionen und Reststoffe vogestellt. Durch Vorschaltung einer Pyrolyse des Klaerschlamms und Nutzung des erzeugten Gases als Reduktionsmittel zur Entsticklung kann die Auswirkung der Mitverbrennung auf Betrieb, Emissionen und Reststoffe der Feuerungsanlage vermindert werden. (orig)

  18. Real time identification of the internal combustion engine combustion parameters based on the vibration velocity signal

    Science.gov (United States)

    Zhao, Xiuliang; Cheng, Yong; Wang, Limei; Ji, Shaobo

    2017-03-01

    Accurate combustion parameters are the foundations of effective closed-loop control of engine combustion process. Some combustion parameters, including the start of combustion, the location of peak pressure, the maximum pressure rise rate and its location, can be identified from the engine block vibration signals. These signals often include non-combustion related contributions, which limit the prompt acquisition of the combustion parameters computationally. The main component in these non-combustion related contributions is considered to be caused by the reciprocating inertia force excitation (RIFE) of engine crank train. A mathematical model is established to describe the response of the RIFE. The parameters of the model are recognized with a pattern recognition algorithm, and the response of the RIFE is predicted and then the related contributions are removed from the measured vibration velocity signals. The combustion parameters are extracted from the feature points of the renovated vibration velocity signals. There are angle deviations between the feature points in the vibration velocity signals and those in the cylinder pressure signals. For the start of combustion, a system bias is adopted to correct the deviation and the error bound of the predicted parameters is within 1.1°. To predict the location of the maximum pressure rise rate and the location of the peak pressure, algorithms based on the proportion of high frequency components in the vibration velocity signals are introduced. Tests results show that the two parameters are able to be predicted within 0.7° and 0.8° error bound respectively. The increase from the knee point preceding the peak value point to the peak value in the vibration velocity signals is used to predict the value of the maximum pressure rise rate. Finally, a monitoring frame work is inferred to realize the combustion parameters prediction. Satisfactory prediction for combustion parameters in successive cycles is achieved, which

  19. Facteurs climatiques et environnementaux des risques palustres ...

    African Journals Online (AJOL)

    La santé des populations est tributaire des conditions climatiques et environnementales dans lesquelles elles vivent. La présente étude analyse les liens entre le climat, l'environnement et la prévalence du paludisme dans le Département des Collines. L'analyse des données pluviométriques, thermométriques et ...

  20. Etude des potentialites germinatives pour une regeneration ...

    African Journals Online (AJOL)

    Les différents aspects germinatifs du fruit de Neocarya macrophylla, ressource génétique fruitière spontanée du Niger, ont fait l'objet d'analyses. L'étude des performances germinatives de cette espèce a donc porté sur des graines récentes et des graines conservées à la température ambiante dans des flacons en verre ...

  1. Integration et exclusion des communautes : La curieuse ...

    African Journals Online (AJOL)

    Le sport s'est imposé aujourd'hui comme un puissant vecteur d'intégration. C'est par la médiation du sport que des individus et des cultures différentes se rencontrent, communient ensemble au cours des compétitions et finissent par se socialiser ou se « resocialiser ». C'est donc dire que le sport contribue à construire des ...

  2. ETUDE DE LA DISTRIBUTION DES CATIONS ECHANGEABLES

    African Journals Online (AJOL)

    SEI Joseph

    déterminé les pourcentages en silice et carbonates. Nous avons aussi mis au point la présence des ions chlorures en pourcentage assez important pouvant être responsable de la corrosion des aciers de frettage des tuyaux en béton précontraint et par conséquent des dégradations affectant ces tuyaux. La présence d'un.

  3. ETUDE DE LA DISTRIBUTION DES CATIONS ECHANGEABLES

    African Journals Online (AJOL)

    SEI Joseph

    pollution. L'objectif du présent travail est l'étude de la qualité des eaux superficielles et souterraines pour évaluer le degré de pollution provenant des lixiviats de la décharge et des cours d'eaux dans lesquels les ..... Les métaux lourds dosés ont montré une pollution métallique des eaux souterraine par rapport à la norme.

  4. Zur odonatenfauna des Fintlandsmoores (Landkreis ammerland)

    OpenAIRE

    Gueffroy, Daniel; Liekweg, Tammo

    2000-01-01

    Zur Untersuchung der Libellenfauna des Fintlandsmoores im Landkreis Ammerland wurden 1999 zehn Exkursionen durchgeführt. Der Untersuchungsschwerpunkt lag im bereich der dystrophen Torfstiche im süden sowie des unabgetorften Hochmoorrestes im Zentrum des Naturschutzgebietes. Insgesamt wurden 15 Libellenarten als bodenständig nachgewiesen. Aufgrund früherer Untersuchungen aus den Jahren 1973-78 und 1986 läßt sich die zunehmende Eutrophierung anhand der Veränderung des Artenspektr...

  5. ETUDE DE LA DISTRIBUTION DES CATIONS ECHANGEABLES

    African Journals Online (AJOL)

    SEI Joseph

    D'autre part, à cause de la corrélation directe entre l'étendue des inondations et les quantités de poissons et de pâturages fournies par la plaine, il y a eu dégradation des ... aux changements climatiques en zone sahélienne du Cameroun. Un des objectifs de notre étude était de préciser le comportement des agriculteurs ...

  6. INSTITUT DE RECHERCHE DES ENERGIES RENOUVELABLES A TLEMCEN « énergie solaire »

    OpenAIRE

    BOUMEDIENE, Hayat; TEKIA, Sarah

    2015-01-01

    L’indépendance énergétique, couplée à la diminution des émissions de gaz à effet de serre et la volonté de diversifier des ressources énergétiques permet de valoriser et d’exploiter les énergies alternatives. De ce fait, les énergies renouvelables représentent une alternative écologique aux combustibles fossiles, elles ont toutes l’immense avantage d’être d’origines naturelles, inépuisables, non polluantes et très adaptées à la production décentralisée. Les divers types d’énergies renouvelabl...

  7. LES APPROCHES PSYCHOSOCIOLOGIQUES DES ORGANISATIONS

    Directory of Open Access Journals (Sweden)

    Deaconu Alecxandrina

    2008-05-01

    Full Text Available Les préoccupations pour bien comprendre la complexité des organisations sont bien connues dans la théorie et la pratique du management. La motivation la plus fréquente pour toutes les recherches et les investigationes faites a été fondée sur le besoin de savoir gérer les situations diverses en vue de maximiser la performance organisationnelle. En ce qui nous concerne, pour enrichir les informations disponibles, nous voulons élargir, dans notre communication, les approches traditionelles, focaliser l’attention sur la dimension psychologiques des organisations et présenter les mécanismes qui favorisent l’implication des salariés.

  8. Parasites et parasitoses des poissons

    OpenAIRE

    De Kinkelin, Pierre; Morand, Marc; Hedrick, Ronald; Michel, Christian

    2014-01-01

    Cet ouvrage, richement illustré, offre un panorama représentatif des agents parasitaires rencontrés chez les poissons. S'appuyant sur les nouvelles conceptions de la classification phylogénétique, il met l'accent sur les propriétés biologiques, l'épidémiologie et les conséquences cliniques des groupes d'organismes en cause, à la lumière des avancées cognitives permises par les nouveaux outils de la biologie. Il est destiné à un large public, allant du monde de l'aquaculture à ceux de la santé...

  9. L’Internet des objets

    OpenAIRE

    Benghozi, Pierre-Jean; Bureau, Sylvain; Massit-Folléa, Françoise

    2012-01-01

    L’ « internet des objets » est une dimension majeure de l’internet du futur. Mais tout le monde ne s’accorde pas encore sur sa définition, ni sur la mesure de son importance économique ou des risques qu’il induit. L’étude de nombreux rapports prospectifs et l’observation des innovations d’ores et déjà engagées a permis de mettre en relief les incertitudes techniques, économiques et socio-politiques qui pèsent sur cette véritable mutation programmée de l’internet et de proposer une approche eu...

  10. Aux origines des Jeux olympiques.

    Directory of Open Access Journals (Sweden)

    Isabelle Debilly

    2005-11-01

    Full Text Available Si les Jo modernes sont régulièrement sous les feux de l’actualité, soit par la répétition temporelle des Olympiades elle-même, soit par les enjeux économiques féroces qui découlent du choix des lieux, ceux de l’Antiquité sont en général cantonnés au domaine scolaire ou universitaire. Néanmoins, ils bénéficient tous les quatre ans d`un éclairage médiatique. L’ouvrage Olympie. La victoire pour les dieux est au croisement des deux domaines. En effet, écrit par un ...

  11. Agent des projets et des partenariats (h/f) | CRDI - Centre de ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    appuie la coordination des activités de mobilisation de ressources et des bailleurs de fonds (politiques et planification, etc.) et l'appui au Comité de gestion de la haute direction et au Conseil des gouverneurs;; facilite des relations clés entre la DPDA et des clients (programmes et bureaux régionaux), le conseiller juridique ...

  12. Quantification des apports et des exores d'un lac : cas du lac Fetzara ...

    African Journals Online (AJOL)

    ... permet de déterminer l'impact des facteurs environnementaux sur les variations de la composition chimique des eaux aux entrées et à la sortie du lac. Les résultats des analyses chimiques couplés aux débits mesurés dans différents points des Oueds Zied, Mellah, Hout et Meboudja ont permis le calcul des flux transitant ...

  13. Potentiel en biogaz des résidus agropastoraux et des excréments ...

    African Journals Online (AJOL)

    La potentialité en biogaz des excréments humains et des résidus agropastoraux du bassin versant du fleuve Sassandra (BVS) a été évaluée à partir des statistiques agricoles et de la population, ainsi que des indices de productivité de biogaz. Egalement, la mise en oeuvre des technologies de production de biogaz dans ...

  14. Prise en charge des urgences au service d'accueil des urgences ...

    African Journals Online (AJOL)

    Introduction: La prise en charge des patients dans les services d'accueil des urgences est une des meilleures vitrines d'un système de santé. En Afrique subsaharienne, la gestion des urgences se heurte à des difficultés humaines et matérielles. Le but de ce travail était d'évaluer les difficultés de prise en charge au Service ...

  15. Synthèse des faits empiriques et des leçons : Comment l ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    IDRC CRDI

    5 déc. 2013 ... and Flora Hewlett Foundation, le programme Croissance de l'Économie et Débouchés Économiques des Femmes ... des enseignements tirés au sujet des liens qui existent entre l'autonomisation économique des femmes ..... examens systématiques à l'aide des principes Cochrane/Campbell/3iE. Toutefois ...

  16. Récupération des eaux grises et des eaux pluviales pour l ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Récupération des eaux grises et des eaux pluviales pour l'agriculture urbaine et périurbaine à La Soukra, dans le gouvernorat d'Ariana (Tunisie). Jusqu'à la fin des années 1960, la plaine de la Soukra était une zone de verdure adjacente à Tunis. Au début des années 1970, les agriculteurs utilisaient des eaux usées ...

  17. Kodifikation des Privatrechts in Ungarn und die Tradition des römischen Rechts

    OpenAIRE

    Hamza, Gabor

    2015-01-01

    Das erste ungarische Zivilgesetzbuch wurde im Jahre 1959 verabschiedet. Das ungarische Zivilgesetzbuch ist am 1. Mai 1960 in Kraft getreten. Das ZGB spiegelt den Einfluss des schweizerischen Zivilgesetzbuches, des schweizerischen Obligationenrechts, des deutschen BGB und des Entwurfes des ungarischen Bürgerlichen Gesetzbuches aus dem Jahre 1928 wider. Das ungarische ZGB hat keinen Allgemeinen Teil, sondern nur in sieben Paragraphen gegliederte einleitende Bestimmungen. Der Kodex gliedert sic...

  18. Étude des politiques relatives à l'établissement des prix et à la ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Étude des politiques relatives à l'établissement des prix et à la taxation de l'alcool en Inde. L'Inde est le troisième marché mondial pour les ... Les données proviendront de sources multiples, dont le National Sample Survey Office et les départements des taxes d'accise des dix États. En fonction des résultats obtenus, les ...

  19. Architecture, des normes et des systèmes d'information libres, phase ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Architecture, des normes et des systèmes d'information libres, phase II (OASIS II) - Renforcement des capacités dans l'ensemble de l'Afrique. Sur presque tout le continent africain, la prestation des services de santé est limitée en raison des maigres ressources disponibles et de la charge de morbidité de plus en plus ...

  20. Intensifier l'inclusion financière des femmes et des jeunes en Afrique ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Intensifier l'inclusion financière des femmes et des jeunes en Afrique subsaharienne. Bien que d'énormes progrès aient été accomplis en vue d'offrir des services financiers à un plus large éventail de clients dans de nombreux pays de l'Afrique subsaharienne, des femmes et des jeunes marginalisés sont toujours laissés ...

  1. Perceptions locales de la manifestation des changements ...

    African Journals Online (AJOL)

    SARAH

    . PRPR. ERMA. DC. UD cluster 1 cluster 2. Pauvres. Riches et moyens. Figure 4. Positionnement des classes d'impacts socio-économiques des changements climatiques dans un système d'axes de l'analyse factorielle des ...

  2. Die Problematik des Begriffes hebraica veritas

    African Journals Online (AJOL)

    p1243322

    Nach ihm waren sowohl der Text des Tanak als auch sein Umfang Ausdruck der wahren Offenbarung Gottes an Israel, daher konnte nur diese Form des Alten Testaments die Wahrheit erhalten. Folgerichtig betrachtete er sie als Bibel der Verfasser des Neuen. Testaments und Norm für Lehre und Leben. Untersucht man die.

  3. Pecheries maritimes artisanales Togolaises : analyse des ...

    African Journals Online (AJOL)

    Pecheries maritimes artisanales Togolaises : analyse des debarquements et de la valeur commerciale des captures. K.M. Sedzro, E.D. Fiogbe, E.B. Guerra. Abstract. Description du sujet : La connaissance scientifique de la pression des pêcheries artisanales sur les ressources marines togolaises s'avère nécessaire pour ...

  4. Migration transnationale des Vietnamiennes en Asie | IDRC ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Souvent, cependant, les pays d'origine ne disposent pas des politiques ni des lois ayant force exécutoire qui permettraient d'assurer des pratiques d'embauche ... Women's movements in India are struggling to address problems arising from rapidly changing social relations and vulnerabilities associated with, among other ...

  5. Caractérisation des plantes médicinales à flavonoïdes des marchés ...

    African Journals Online (AJOL)

    Les plantes à flavonoïdes constituent un atout majeur pour le maintien de la santé. Le présent travail a été conduit dans deux marchés de la ville de Douala afin de valoriser l'utilisation des plantes à flavonoïdes dans la médecine traditionnelle. Des enquêtes ethnobotaniques réalisées auprès de 40 vendeurs des plantes ...

  6. Improved Economic Performance of Municipal Solid Waste Combustion Plants by Model Based Combustion Control

    NARCIS (Netherlands)

    Leskens, M.

    2013-01-01

    The combustion of municipal solid waste (MSW) is used for its inertisation, reduction of its volume and the conversion of its energy content into heat and/or electricity. Operation and control of modern large scale MSW combustion (MSWC) plants is determined by economic and environmental objectives

  7. Combustion stratification study of partially premixed combustion using Fourier transform analysis of OH* chemiluminescence images

    KAUST Repository

    Izadi Najafabadi, Mohammad

    2017-11-06

    A relatively high level of stratification (qualitatively: lack of homogeneity) is one of the main advantages of partially premixed combustion over the homogeneous charge compression ignition concept. Stratification can smooth the heat release rate and improve the controllability of combustion. In order to compare stratification levels of different partially premixed combustion strategies or other combustion concepts, an objective and meaningful definition of “stratification level” is required. Such a definition is currently lacking; qualitative/quantitative definitions in the literature cannot properly distinguish various levels of stratification. The main purpose of this study is to objectively define combustion stratification (not to be confused with fuel stratification) based on high-speed OH* chemiluminescence imaging, which is assumed to provide spatial information regarding heat release. Stratification essentially being equivalent to spatial structure, we base our definition on two-dimensional Fourier transforms of photographs of OH* chemiluminescence. A light-duty optical diesel engine has been used to perform the OH* bandpass imaging on. Four experimental points are evaluated, with injection timings in the homogeneous regime as well as in the stratified partially premixed combustion regime. Two-dimensional Fourier transforms translate these chemiluminescence images into a range of spatial frequencies. The frequency information is used to define combustion stratification, using a novel normalization procedure. The results indicate that this new definition, based on Fourier analysis of OH* bandpass images, overcomes the drawbacks of previous definitions used in the literature and is a promising method to compare the level of combustion stratification between different experiments.

  8. Potential of Porous-Media Combustion Technology as Applied to Internal Combustion Engines

    Directory of Open Access Journals (Sweden)

    Miroslaw Weclas

    2010-01-01

    Full Text Available The paper summarizes the knowledge concerning porous media combustion techniques as applied in engines. One of most important reasons of this review is to introduce this still not well known technology to researchers doing with internal combustion engine processes, thermal engines, reactor thermodynamics, combustion, and material science. The paper gives an overview of possible applications of a highly porous open cell structures to in-cylinder processes. This application means utilization of unique features of porous media for supporting engine processes, especially fuel distribution in space, vaporization, mixing with air, heat recuperation, ignition and combustion. There are three ways for applying porous medium technology to engines: support of individual processes, support of homogeneous combustion process (catalytic and non-catalytic with temperature control, and utilization of the porous structure as a heat capacitor only. In the first type of application, the porous structure may be utilized for fuel vaporization and improved fuel distribution in space making the mixture more homogeneous in the combustion chamber. Extension of these processes to mixture formation and ignition inside a combustion reactor allows the realization of a homogeneous and a nearly zero emissions level combustion characterized by a homogeneous temperature field at reduced temperature level.

  9. Cardiotoxicité des psychotropes

    OpenAIRE

    TAHIRI, Abdallah

    2013-01-01

    Même à dose thérapeutique, les médicaments psychotropes sont susceptibles d'engendrer des troubles du rythme cardiaque graves avec risque létal concourant à expliquer la pré valence de la mort subite dans la population psychiatrique. Les situations cliniques à risque telles que poly médication (des psychotropes entre eux ou d'un psychotrope avec un non psychotrope allongeur de QTc), interactions médicamenteuses aussi bien pharmacodynamiques que pharmacocinétiques, traitement pa...

  10. (AJST) BIOSTRATIGRAPHIE DES FORAMINIFERES ET ...

    African Journals Online (AJOL)

    2Département de Géologie, Faculté des Sciences, Université d'Ibadan, Ibadan, Nigeria. 3Département de Géologie et Sciences de l'Environnement, Université de Buea, Cameroun. ARESUME:- 115 déblais de sondage et des ..... Cette méthode a été appliquée au lieu de la première apparition et de la denière apparition ...

  11. Liquid rocket combustion chamber acoustic characterization

    Directory of Open Access Journals (Sweden)

    Cândido Magno de Souza

    2010-09-01

    Full Text Available Over the last 40 years, many solid and liquid rocket motors have experienced combustion instabilities. Among other causes, there is the interaction of acoustic modes with the combustion and/or fluid dynamic processes inside the combustion chamber. Studies have been showing that, even if less than 1% of the available energy is diverted to an acoustic mode, combustion instability can be generated. On one hand, this instability can lead to ballistic pressure changes, couple with other propulsion systems such as guidance or thrust vector control, and in the worst case, cause motor structural failure. In this case, measures, applying acoustic techniques, must be taken to correct/minimize these influences on the combustion. The combustion chamber acoustic behavior in operating conditions can be estimated by considering its behavior in room conditions. In this way, acoustic tests can be easily performed, thus identifying the cavity modes. This paper describes the procedures to characterize the acoustic behavior in the inner cavity of four different configurations of a combustion chamber. Simple analytical models are used to calculate the acoustic resonance frequencies and these results are compared with acoustic natural frequencies measured at room conditions. Some comments about the measurement procedures are done, as well as the next steps for the continuity of this research. The analytical and experimental procedures results showed good agreement. However, limitations on high frequency band as well as in the identification of specific kinds of modes indicate that numerical methods able to model the real cavity geometry and an acoustic experimental modal analysis may be necessary for a more complete analysis. Future works shall also consider the presence of passive acoustic devices such as baffles and resonators capable of introducing damping and avoiding or limiting acoustic instabilities.

  12. Internal Heterogeneous Processes in Aluminum Combustion

    Science.gov (United States)

    Dreizin, E. L.

    1999-01-01

    This paper discusses the aluminum particle combustion mechanism which has been expanded by inclusion of gas dissolution processes and ensuing internal phase transformations. This mechanism is proposed based on recent normal and microgravity experiments with particles formed and ignited in a pulsed micro-arc. Recent experimental findings on the three stages observed in Al particle combustion in air and shows the burning particle radiation, trajectory (streak), smoke cloud shapes, and quenched particle interiors are summarized. During stage I, the radiation trace is smooth and the particle flame is spherically symmetric. The temperature measured using a three-color pyrometer is close to 3000 K. Because it exceeds the aluminum boiling point (2730 K), this temperature most likely characterizes the vapor phase flame zone rather than the aluminum surface. The dissolved oxygen content within particles quenched during stage I was below the detection sensitivity (about 1 atomic %) for Wavelength Dispersive Spectroscopy (WDS). After an increase in the radiation intensity (and simultaneous decrease in the measured color temperature from about 3000 to 2800 K) indicative of the transition to stage II combustion, the internal compositions of the quenched particles change. Both oxygen-rich (approx. 10 atomic %) and oxygen-lean (combustion behavior and the evolution of its internal composition, the change from the spherically symmetric to asymmetric flame shape occurring upon the transition from stage I to stage II combustion could not be understood based only on the fact that dissolved oxygen is detected in the particles. The connection between the two phenomena appeared even less significant because in earlier aluminum combustion studies carried in O2/Ar mixtures, flame asymmetry was not observed as opposed to experiments in air or O2/CO mixtures. It has been proposed that the presence of other gases, i.e., hydrogen, or nitrogen causes the change in the combustion regime.

  13. Generalities on the dynamic behaviour of rapid reactors. Preliminary studies on Rapsodie; Generalites sur le comportement dynamique des piles rapides. Etudes preliminaires de rapsodie

    Energy Technology Data Exchange (ETDEWEB)

    Campan, J.L.; Chaumont, J.P.; Clauzon, P.P.; Ghesquiere, G.; Leduc, J.; Schmitt, A.P.; Zaleski, C.P. [Commissariat a l' Energie Atomique, Cadarache (France). Centre d' Etudes Nucleaires

    1963-07-01

    The study of the dynamic behaviour of fast reactors may be divided into three section: 1. Stability studies around equilibrium power only the linear case was examining. S. Transient studies in the case of usual reactor operation (shut down, scram, etc.) with thermal shocks evaluation, for instance. 3. Explosion studies, for the maximum credible accidents. This report presents the status of the studies performed at the 'Physics Research Department' at Cadarache. Methods used are detailed and illustrated with the results obtained on a preliminary metallic core of the Rapsodie Reactor. (authors) [French] Le comportement dynamique des piles rapides, se presente tout naturellement sous trois aspects: 1. Etude de stabilite autour d'un regime d'equilibre (nous nous sommes bornes ici au cas lineaire). 2. Etude de regimes transitoires lors des operations normales de pile (arret, arret d'urgence, etc.) avec evaluation des chocs thermiques par exemple. 3. Etude des regimes transitoires de caractere explosif lors des accidents les plus graves possibles. Ce rapport presente l'etat des etudes a la date du 20 decembre 1961 a la Section d'Etudes de Piles Rapides a CADARACHE. Les methodes employees ont ete detaillees et illustrees a partir des resultats obtenus sur une premiere version 'combustible metallique' de Rapsodie. (auteurs)

  14. Contribution des radios communautaires a l'education des ...

    African Journals Online (AJOL)

    TIC » ont sur l'éducation des adolescents. Par une démarche d'étude essentiellement transversale, quantitative et qualitative, nous avons interrogé 160 sujets et les données collectées ont fait découvrir autant d'influences positives que ...

  15. Cartographie des zones d'intervention des partenaires techniques et ...

    African Journals Online (AJOL)

    Il s'agit des Communes ayant 7 à 10 partenaires (niveau 1), les. Communes ayant 11 à 14 (niveau 2) et les Communes ayant plus de 15 partenaires (niveau 3). Mots clés : Cartographie, Bénin, zones d'intervention, partenaires techniques et financiers (PTF), taux spatial d'intervention (TSI), taux de population couverte ...

  16. Traits morphologiques des graines et vigueur des jeunes plants de ...

    African Journals Online (AJOL)

    écologique du Sénégal afin de pouvoir sélectionner une meilleure semence qui sera destinée aux programmes de développement des énergies renouvelables. Morphological traits of seeds and seedling vigor of two sources of Jatropha curcas L. in ...

  17. Traits morphologiques des graines et vigueur des jeunes plants de ...

    African Journals Online (AJOL)

    SARAH

    écologique du Sénégal afin de pouvoir sélectionner une meilleure semence qui sera destinée aux programmes de développement des énergies renouvelables. Journal of Applied Biosciences 88:8249– 8255. ISSN 1997–5902 ...

  18. Evaluation des conditions de germination des noyaux de Grewia ...

    African Journals Online (AJOL)

    personnel

    31 janv. 2014 ... 1Laboratoire de Physiologie et Production Végétales, Université Marien NGOUABI,. Faculté des Sciences et Techniques, BP.69. Brazzaville, Republique du Congo. 2Ecole Nationale Supérieure d'Agronomie et Forestérie, Université Marien NGOUABI,. BP. 69. Brazzaville, Republique du Congo.

  19. Assessment of Literature Related to Combustion Appliance Venting Systems

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, V. H.; Less, B. D.; Singer, B. C.; Stratton, J. C.; Wray, C. P.

    2015-02-01

    In many residential building retrofit programs, air tightening to increase energy efficiency is often constrained by safety concerns with naturally vented combustion appliances. Tighter residential buildings more readily depressurize when exhaust equipment is operated, making combustion appliances more prone to backdraft or spill combustion exhaust into the living space. Several measures, such as installation guidelines, vent sizing codes, and combustion safety diagnostics, are in place with the intent to prevent backdrafting and combustion spillage, but the diagnostics conflict and the risk mitigation objective is inconsistent. This literature review summarizes the metrics and diagnostics used to assess combustion safety, documents their technical basis, and investigates their risk mitigations. It compiles information from the following: codes for combustion appliance venting and installation; standards and guidelines for combustion safety diagnostics; research evaluating combustion safety diagnostics; research investigating wind effects on building depressurization and venting; and software for simulating vent system performance.

  20. Investigating co-combustion characteristics of bamboo and wood.

    Science.gov (United States)

    Liang, Fang; Wang, Ruijuan; Jiang, Changle; Yang, Xiaomeng; Zhang, Tao; Hu, Wanhe; Mi, Bingbing; Liu, Zhijia

    2017-11-01

    To investigate co-combustion characteristics of bamboo and wood, moso bamboo and masson pine were torrefied and mixed with different blend ratios. The combustion process was examined by thermogravimetric analyzer (TGA). The results showed the combustion process of samples included volatile emission and oxidation combustion as well as char combustion. The main mass loss of biomass blends occurred at volatile emission and oxidation combustion stage, while that of torrefied biomass occurred at char combustion stage. With the increase of bamboo content, characteristic temperatures decreased. Compared with untreated biomass, torrefied biomass had a higher initial and burnout temperature. With the increase of heating rates, combustion process of samples shifted to higher temperatures. Compared with non-isothermal models, activation energy obtained from isothermal model was lower. The result is helpful to promote development of co-combustion of bamboo and masson pine wastes. Copyright © 2017 Elsevier Ltd. All rights reserved.