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Jansson, Åsa. "En livscykelanalys av en del i livsmedelskedjan." Thesis, Linköping University, Department of Thematic Studies, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2488.
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Framtidens konsumtion och produktion av animalieprodukter måste vara ekologiskt hållbart ur ett globalt och regionalt perspektiv, vilket avser minimal miljöpåverkan och effektivt utnyttjande av naturresurser. Syftet med denna studie är dels att ta fram inventeringsdata för en premix, vilket är en fodertillsatsprodukt, med en omfattning ”från vaggan till färdig produkt”, dels att bedöma om premix utgör en betydande miljöaspekt i förhållande till en persons indirekta årliga konsumtion jämfört med medelsvenskens totala miljöpåverkan. Mot denna bakgrund har en livscykelanalys utförts på en specifik premix för nötkreatur. Bedömningen av miljöpåverkan görs med en metod som baseras på de svenska miljökvalitetsmålen.
Resultatet av den genomförda livscykelanalysen resulterar i inventeringsdata för 1 ton premix. Denna typ av uppgifter kan användas som indata i andra livscykelanalyser. Vidare visar den genomförda LCA att den nuvarande konsumtionen av premixen inte är en betydande miljöaspekt i förhållande till den miljöpåverkan som en individ ger upphov till. Den tillämpade normaliseringsmetoden som baseras på de nationella miljökvalitetsmålen i kombination med en individs årliga orsakade miljöpåverkan gör att denna typ av analyser kan användas för att bedöma om vi har en ekologisk hållbar livsstil. Den största delen av premixens miljöpåverkan utgörs av råvaruframställning och transporter som bidrar till klimatförändring, försurning och eutrofiering men även bildandet av marknära ozon. Det är framförallt användningen av fossila resurser som utgör denna miljöpåverkan. Slutsatsen av studien är att foderindustrin som är en del i livsmedelsektorn, kan minska sin miljöpåverkan genom att främst minska användningen av fossila resurser genom livscykelkedjan. Användningen av fossila bränslen kommer främst ifrån transporter och råvaruframställning.
Livscykelanalyser är ett verktyg som kan hjälpa företag och branscher att identifiera betydande miljöaspekter i livscykelkedjan. Genom att i livscykelanalysen använda en bedömningsmetod som baseras på de nationella miljökvalitetsmålen kan miljömålsarbetet utvärderas och nya mål upprättas. Livscykelanalyser är därmed ett verktyg som kan komma att utgöra ett viktigt verktyg i arbetet att uppnå en ekologiskt hållbar utveckling.
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Gu, Xin. "Numerical Simulation of Conventional Fuels and Biofuels Dispersion and Vaporization Process in Co-flow and Cross-flow Premixers." Doctoral diss., University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5232.
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In order to follow increasingly strict regulation of pollutant emissions, a new concept of Lean Premixed pre-vaporized (LPP) combustion has been proposed for turbines. In LPP combustion, controlled atomization, dispersion and vaporization of different types of liquid fuel in the pre-mixer are the key factors required to stabilize the combustion process and improve the efficiency. A numerical study is conducted for the fundamental understanding of the liquid fuel dispersion and vaporization process in pre-mixers using both cross-flow and co-flow injection methods. First, the vaporization model is validated by comparing the numerical data to existing experiments of single droplet vaporization under both low and high convective air temperatures. Next, the dispersion and vaporization process for biofuels and conventional fuels injected transversely into a typical simplified version of rectangular pre-mixer are simulated and results are analyzed with respect to vaporization performance, degree of mixedness and homogeneity. Finally, collision model has been incorporated to predict more realistic vaporization performance. Four fuels, Ethanol, Rapeseed Methyl Esters (RME), gasoline and jet-A have been investigated. For mono-disperse spray with no collision model, the droplet diameter reduction and surface temperature rise were found to be strongly dependent on the fuel properties. The diameter histogram near the pre-mixer exit showed a wide droplet diameter distribution for all the fuels. In general, pre-heating of the fuels before injection improved the vaporization performance. An improvement in the drag model with Stefan flow correction showed that a low speed injection and high cone angle improved performance. All fuels achieved complete vaporization under a spray cone angle of 140°. In general, it was found that cross-flow injection achieved better vaporization performance than co-flow injection. A correlation is derived for jet-A's total vaporization performance as a function of non-dimensional inlet air temperature and fuel/air momentum flux ratio. This is achieved by curve-fitting the simulated results for a broad range of inlet air temperatures and fuel/air momentum flux ratios. The collision model, based on no-time-counter method (NTC) proposed by Schmidt and Rutland, was implemented to replace O'Rourke's collision algorithm to improve the results such that the unphysical numerical artifact in a Cartesian grid was removed and the results were found to be grid-independent. The dispersion and vaporization processes for liquid fuel sprays were simulated in a cylindrical pre-mixer using co-flow injection method. Results for jet-A and Rapeseed Methyl Esters (RME) showed acceptable grid independence. At relatively low spray cone angle and injection velocity, it was found that the collision effect on the average droplet size and the vaporization performance were very high due to relatively high coalescence rate induced by droplet collisions. It was also found that the vaporization performance and the level of homogeneity of fuel-air mixture could be significantly improved when the dispersion level is high, which can be achieved by increasing the spray cone angle and injection velocity. In order to compare the performance between co-flow and cross-flow injection methods, the fuels were injected at an angle of 40° with respect to the stream wise direction to avoid impacting on the wall. The cross-flow injection achieved similar vaporization performance as co-flow because a higher coalescence rate induced by droplet collisions cancelled off its higher heat transfer efficiency between two phases for cross-flow injections.ID: 031001450; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Adviser: Ranganathan Kumar.; Title from PDF title page (viewed July 2, 2013).; Thesis (Ph.D.)--University of Central Florida, 2012.; Includes bibliographical references (p. 148-157).
Ph.D.
Doctorate
Mechanical and Aerospace Engineering
Engineering and Computer Science
Mechanical Engineering
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Svatý, Lukáš. "HDR video "plugin" pro Adobe Premier." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2015. http://www.nusl.cz/ntk/nusl-264960.
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Cílem práce je vytvoření podpory pro editovaní videa v HDR formátu. Pro editaci videa je zvolen program Adobe Premiere Pro a na dosažení požadovaného výsledku je vytvořen plugin do zmiňovaného softwaru, který poskytuje požadovanou funkcionalitu. V práci jsou vysvětleny principy vytváření, zobrazení a ukládáni obsahu z rozšíreným dynamickým rozsahem. Zároveň jsou vysvětleny principy vytváření pluginů pro Adobe Premiere Pro za pomoci SDK verze CS6. V praktické části této práce jsou vysvětleny detaily implementace, problémy, které byly řešené, a popis samotného pluginu. Návrh pluginů je vytvořen tak, aby byla možná další práce na tomto softwaru, přidaní další funkcionality a pro umožnění využití tohoto díla na rozvoji obsahu s rozšíreným dynamickým rozsahem.
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Igrényi, Réka. "Controlling." Master's thesis, Vysoká škola ekonomická v Praze, 2012. http://www.nusl.cz/ntk/nusl-165549.
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The aim of this Master's thesis was to characterize the current cost ratio, pricing system and profitability of an agricultural firm, called P.G.TRADE, spol s r.o.. This company is engaged in the production and sale of compound feeds and premixes, resp. in storing different kinds of agricultural commodities. My specific aim was to determine whether the current pricing system and prices cover all the costs which incurred because of the processes of production and sale of finished products and that in doing so provides a satisfactory level of profitability, too. In the first, methodological part, I summarized all the necessary theoretical knowledge that we need to know about controlling. I paid particularly big attention to calculations and budgeting. In the application part I focused on the characteristics of the company itself and on the analysis of the costs and of the pricing system. In the next part I described in details the manufacturing processes of compound feeds and premixes in the company's main factory in Dvory nad Žitavou. The last part is devoted to the calculation of production costs and identifying weaknesses. In addition to the description of the conclusions I tried to propose some measures that could help in improving the company's profitability.
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BREVET, BARBAUD ANNE LAURE. "Le sujet et ses reflets dans l'oeuvre romanesque de doris lessing." Paris 3, 1998. http://www.theses.fr/1998PA030074.
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Dans les romans de dons lessing, il existe une quete de l'unite subjective visant a la formation de l'individu, a travers une ecriture dont l'objet est de rassembler les fragment multiples et contradictoires de l'experience vecue et de l'histoire. Dans les roman autobiographiques, la narration dite + a la troisieme personne ; est toujours sous-tendue par un + je ;, ce qui a pour effet de transmuer la representation traditionnellement realiste en un discours bivocal, renvoyant de maniere indirecte a une image plausible du sujet de l'ecriture aussi le systeme de reflets dans le texte lessinien s'organise-t-il autour du sujet fictif intratextuel, refletant et reflecteur, dont l'identite individuelle s'avere a la fois transcendee e constituee par l'experience d'un espace speculaire inconscient. Tandis que le recit tend a figurer l'avenement d'une identite, qui, en derniere instance, ressortit a l'ipseite du texte, les dispositifs scripturaux, rythmes ou motifs, refletent les origines subjectives du processus de creation litteraire. L'ecriture speculaire offre une narration complexe, fragmentee en recits reflexifs, enchassants ou enchasses. Le roman lessinien, par sa visee memorialiste, aboutit a une combinatoire evenementielle fondee sur la reprise, la redondance, voire le ressassement, tout en convoquant une multiplicite dialogique de recits. L'evenement vecu ainsi repris, rememore. Interprete et ecrit passe necessairement par le filtre analytique de la litterature, ou il se voit reflechi au miroir de la conscience ecrivanteThroughout her novels, doris lessing is seeking to build the subjective oneness of individual self, using her art to reassemble the multiple, often contradictory facets of personal life in its relations with collective history. The narrative handling of this issue, particularly in lessing's autobiographical novels, presents itself as a 'third-person', omniscient 'voice', which nonetheless indirectly conveys the utterance of a tirst-person' self. As a result, traditional representation is reshaped into bivocal discourse, diffusely reflecting a plausible mirror-image of the writer at work. Hence the narrative patterns of reflection appear to be connected to the main character at the core of lessing's fiction, whose role as a fictitious, intradiegetic self is to diffract and focalize a personal image of reality. Besides, selfhood reveals itself as being transcended as well as built up when confronted to the inner mirror of the unconscious. Apart from attempting to state the birth of an individuality - which is eventually relevant to the singular qualities of lessing's novels themselves -, textual devices such as the arrangement of stylistic rhythms and patterns allude to the subjective origins of the writing process. In this respect, metafictional writing provides the reader with the complexities of discontinuous narration, for its 'reflexive' / 'self-conscious' pieces can be regarded, according to their textual location, either a'embedding' or 'embedded'. Since doris lessing's novels also aim at recording the spirit of the times, her fiction leads up to combine re-used material and to ground the action in repetition, indeed redundancy, while creating a variety of dialogic, self-contained stories. Thus reconsidered, remembered and necessarily interpreted, written events are filtered through the prism literature, where they come to be mirrored by the
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Vincent-Munnia, Nathalie. "Les premiers poèmes en prose : généalogie d'un genre dans la première moitié du dix-neuvième siècle français." Lyon 2, 1994. http://www.theses.fr/1994LYO20006.
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L'expression "poème en prose" ne naît pas au 19e siècle : tout au long du 18e siècle, elle sert à caractériser une prose qui peut acquérir un statut poètique, parallèlement au vers, lequel ne détermine plus dès lors systématiquement ni exclusivement l'existence de la poésie. Mais, dans les premières décennies du 19e, la reconnaissance de cette poésie en prose étant plus définitive, la prose peut s'élaborer plus spécifiquement en poème (au sens moderne du terme, non plus au sens classique et analogique d'"ouvrage de style poétique" ou d'"épopée en prose"). Elle suscite alors un nouveau type de poeticité, abandonnant les normes prédéfinies, qui rendent impossible toute définition systématique et modélisante du genre. Ce type de poétique inédit ne trouve son actualisation que dans l'activité de reconnaissance du lecteur. Le poème en prose est par conséquent dépendant de sa réception -problématique au début du 19e. Les auteurs de ces premiers poèmes en prose (L. De Cailleux, A. Rabbe, A. Bertrand, X. Forneret, M. De Guérin, J. Lefebre-Deumier) font en outre de ce nouvel instrument poétique le moyen en même temps que l'objet d'une quête poétique d'un nouvel ordre. Le poème en prose acquiert ainsi une valeur exploratoire et expérimentale. Initiateur de nouveaux types de poéticité, il élabore aussi des processus de réflexivité poétique (de réflexion du poétique par lui-même et sur lui-même), qui détermineront les évolutions ultérieures de la poésieThe expression "prose poem" does not appear in the nineteenth century : throughout the eighteenth century, it is used to distinguish a prose which can pretend to a poetical status, in the same way as verse (that from then on neither systemat ically nor exclusively determines the existence of poetry). But, during the first decades of the nineteenth century, after the more definitive recognition of this prose poetry, the prose can be elaborated more specifically as a poem (in the modern use of the term, and no longer in the classical and analogical sense of "work in poetic style" or "prose epic"). It creates then a new type of poeticity, abandoning the predefined norms and thus benefiting from non predetermined poetic effects which make any systematic and modelising definition of the genre impossible. This kind of original poetic owes its actualization uniquely to the recognition activity of its reader. The prose poem is consequently dependent on its receipt - problematical at the beginning of the nineteenth century. Furthermore, the authors of these first prose poems (ludovic de cailleux, alphonse rabbe, aloysius bertrand, xavier forneret, maurice de guerin and jules lefevre-deumier) not only make this new poetics instrument the object but also the means of a new order poetical quest. The prose poem thus acquires an exploratory and experimental value. Initiator of new types of poeticity, it also elaborates some processes of poetical reflection (by itself and upon itsel), which will determine the subsequent evolutions of poetry. Open and uncertain, the genre therefore also appears as eminently virtual and paradoxical : its generic identity being built upon its capacity to inaugurate new modes of poeticity and genericity, it is doomed to see this generic specificity dissolve at the very moment that it accedes to an entire recognition
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Arpin, Jonatan. "Utilisation d'une approche historico-culturelle dans le matériel didactique de la première année du premier cycle du secondaire en mathématiques." Thèse, Université du Québec à Trois-Rivières, 2009. http://depot-e.uqtr.ca/2009/1/030105450.pdf.
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Porumbel, Ionut. "Large Eddy Simulation of premixed and partially premixed combustion." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14050.
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Large Eddy Simulation (LES) of bluff body stabilized premixed and partially premixed combustion close to the flammability limit is carried out in this thesis. The LES algorithm has no ad-hoc adjustable model parameters and is able to respond automatically to variations in the inflow conditions.
Algorithm validation is achieved by comparison with reactive and non-reactive experimental data.
In the reactive flow, two scalar closure models, Eddy Break-Up (EBULES) and Linear Eddy Mixing (LEMLES), are used and compared. Over important regions, the flame lies in the Broken Reaction Zone regime. Here, the EBU model assumptions fail. The flame thickness predicted by LEMLES is smaller and the flame is faster to respond to turbulent fluctuations, resulting in a more significant wrinkling of the flame surface. As a result, LEMLES captures better the subtle effects of the flame-turbulence interaction.
Three premixed (equivalence ratio = 0.6, 0.65, and 0.75) cases are simulated. For the leaner case, the flame temperature is lower, the heat release is reduced and vorticity is stronger. As a result, the flame in this case is found to be unstable. In the rich case, the flame temperature is higher, and the spreading rate of the wake is increased due to the higher amount of heat release
Partially premixed combustion is simulated for cases where the transverse profile of the inflow equivalence ratio is variable. The simulations show that for mixtures leaner in the core the vortical pattern tends towards anti-symmetry and the heat release decreases, resulting also in instability of the flame. For mixtures richer in the core, the flame displays sinusoidal flapping resulting in larger wake spreading.
More accurate predictions of flame stability will require the use of detailed chemistry, raising the computational cost of the simulation. To address this issue, a novel algorithm for training Artificial Neural Networks (ANN) for prediction of the chemical source terms has been implemented and tested. Compared to earlier methods, the main advantages of the ANN method are in CPU time and disk space and memory reduction.
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Porumbel, Ionuţ. "Large Eddy Simulation of premixed and partially premixed combustion." Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-11042006-042840/.
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Thesis (Ph. D.)--Aerospace Engineering, Georgia Institute of Technology, 2007.Yeung, Pui-Kuen, Committee Member ; Lieuwen, Tim, Committee Member ; Menon, Suresh, Committee Chair ; Seitzman, Jerry, Committee Member ; Syed, Saadat, Committee Member.
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Staufer, Max. "Large eddy simulation of premixed and partially premixed flames." Düsseldorf VDI-Verl, 2009. http://d-nb.info/995738297/04.
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Sadasivuni, S. K. "LES modelling of non-premixed and partially premixed turbulent flames." Thesis, Loughborough University, 2009. https://dspace.lboro.ac.uk/2134/5804.
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A large eddy simulation (LES) model has been developed and validated for turbulent non-premixed and partially premixed combustion systems. LES based combustion modelling strategy has the ability to capture the detailed structure of turbulent flames and account for the effects of radiation heat loss. Effects of radiation heat loss is modelled by employing an enthalpy-defect based non-adiabatic flamelet model (NAFM) in conjunction with a steady non-adiabatic flamelet approach. The steady laminar flamelet model (SLFM) is used with multiple flamelet solutions through the development of pre-integrated look up tables. The performance of the non-adiabatic model is assessed against experimental measurements of turbulent CH4/H2 bluff-body stabilized and swirl stabilized jet flames carried out by the University of Sydney combustion group. Significant enhancements in the predictions of mean thermal structure have been observed with both bluff body and swirl stabilized flames by the consideration of radiation heat loss through the non-adiabatic flamelet model. In particular, mass fractions of product species like CO2 and H2O have been improved with the consideration of radiation heat loss. From the Sydney University data the HM3e flame was also investigated with SLFM using multiple flamelet strategy and reasonably fair amount of success has been achieved. In this work, unsteady flamelet/progress variable (UFPV) approach based combustion model which has the potential to describe both non-premixed and partially premixed combustion, has been developed and incorporated in an in-house LES code. The probability density function (PDF) for reaction progress variable and scalar dissipation rate is assumed to follow a delta distribution while mixture fraction takes the shape of a beta PDF. The performance of the developed model in predicting the thermal structure of a partially premixed lifted turbulent jet flame in vitiated co-flow has been evaluated. The UFPV model has been found to successfully predict the flame lift-off, in contrast SLFM results in a false attached flame. The mean lift-off height is however over-predicted by UFPV-δ function model by ~20% for methane based flame and under-predicted by ~50% for hydrogen based flame. The form of the PDF for the reaction progress variable and inclusion of a scalar dissipation rate thus seems to have a strong influence on the predictions of gross characteristics of the flame. Inclusion of scalar dissipation rate in the calculations appears to be successful in predicting the flame extinction and re-ignition phenomena. The beta PDF distribution for the reaction progress variable would be a true prospect for extending the current simulation to predict the flame characteristics to a higher degree.
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Boisson, Hugues. "La céramique non tournée du premier age du fer en Languedoc occidental : caractérisation d'un faciès culturel et impacts des premiers échanges méditerranéens." Montpellier 3, 2004. http://www.theses.fr/2004MON30003.
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Aux différents territoires géographiques composant la côte méditerranéenne correspondent des entités culturelles humaines s'affirmant dès la Protohistoire. Le Languedoc occidental, s'étendant entre les Corbières et le fleuve Hérault, est l'une de ces composantes. Une culture s'affirme dans ce territoire durant le premier Age du Fer, reconnue en premier lieu par ses vestiges les plus abondants, la céramique réalisée sans l'usage du tour de potier. Cependant, certaines séries majeures restaient à étudier. Ces études effectuées, un nouveau bilan prenait tout son sens, tant au niveau de l'affinement des typologies et à la caractérisation des céramiques, qu'à celui de la compréhension des mécanismes et des critères de production. L'évolution de la céramique non tournée du Languedoc occidental offre ainsi l'image d'une société ouverte aux influences méditerranéennes et continentales dès le début du VIIe s. , ouverture favorisant les transferts de techniques et les changements sociaux-culturelsSeveral cultural groups are linked to the many geographic territory on Mediterranean coast during Bronze and Iron Ages. In the western part of Languedoc, one of these human community has been distinguished through the vestiges of indigenous potteries made without potter's wheel. During the first Iron Age, the Mediterranean trade is beginning with the indigenous populations. Therefore, many social changes are perceivable through material culture. Indeed, most of these archaeological artefacts had to been studied. The purpose of this work is to complete the typological and chronological sequences of these potteries, as well as ascertaining the technological process of production. This analysis is linked to the problematic of social and technological acculturation process during Early Iron Age in the Western Mediterranean area
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Ravikanti, Veera Venkata Satyanarayana M. "Advanced flamelet modelling of turbulent non-premixed and partially premixed combustion." Thesis, Loughborough University, 2008. https://dspace.lboro.ac.uk/2134/34739.
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Current work focuses on the development and performance evaluation of advanced flamelet models for turbulent non-premixed and partially premixed combustion in RANS and large eddy simulation (LES) based modelling. A RANS-based combustion modelling strategy which has the ability to capture the detailed structure of turbulent non-premixed flames, including the pollutant NO, and account for the effects of radiation heat loss and transient evolution of NO, has been developed and incorporated into the in-house RANS code. The strategy employs an 'enthalpy defect'-based non-adiabatic flamelet model in conjunction with steady or unsteady nonadiabatic flamelets based NO submodels.
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Chateau-Baques, Marie-Christine. "Comment enseigner la culture contemporaine en classe de première ? : une expérience d'initiation à la cuture artistique du premier XXe siècle par le domaine plastique et visuel dans le cadre du programme d'histoire de première." Paris 7, 1993. http://www.theses.fr/1993PA070005.
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Une initiation a la culture artistique, a celle du premier vingtieme siecle en particulier, est-elle possible dans le cadre de l'enseignement de l'histore? a quelle demarche pedagogique et a quelle methodologie recourir pour concilier les contraintes institutionnelles, celles d'un objet d'enseignement relevant de champs disciplinaires pluriels mais inscrits dans le cadre de l'enseignement de l'histoire et celles qu'imposent les demarches d'apprentissage des eleves? quel apport une telle demarche fournit-elle a la didactique de l'histoire? a travers l'elaboration, la mise en oeuvre et la critique de cinq sequences d'enseignement portant sur la domaine plastique et visuel dans le cadre du cours d'histoire, cette these tente de presenter des elements pour une didactique a meme de creer chez les eleves les conditions d'une evolution de leur representations de la culture et de l'art et de renforcer leur apprentissage de l'histoire. L'approche choisie, une approche de type evaluatif tendant vers l'experimentation, permet, par l'analyse et la critique des demarches successives mises en oeuvre, d'amorcer une reflexion sur la structuration de l'enseignement de l'histoire et les representations des elevesThe question is to know wheter an initiation to artistic culture, especially that of the first part of the twentieth century, can be included in an history class, in order to make different obligations coincide obligations resulting from a subject matter tied to different fields, yet pertaining to the teaching of history, and those obligations made necessary by the students' learning processes. The question is to know wether the methods used to achieve this experience can improve the conception of the teaching of history, this thesis aims at finding elements for a teaching method through an experience with two eleventh grade classes in artistic and visual fields. The teaching method aims at making the students' perception of art change. As well as to help them improve their ways of learning history. Through the analysis and critician of the successive ways of the experience, such a way of doing makes it possible to think about the teaching of history as far as its structure and mental images of the students are concerned
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Al, Malki Faisal Abdullah. "Influence of flow on the propagation of premixed and partially premixed flames." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.496691.
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We study in this thesis the influence of prescribed flows on three distinct types of flame, namely flame balls, premixed flames and triple flames. The interaction between flame propagation and fluid flow is examined using asymptotic analyses and numerical simulations of thermo-diffusive models. We consider first the effect of a flow of hot inert gas, either a source or a sink, located at the origin of flame balls. It is shown that the flow gives rise to new kinds of flame balls characterised by having nonzero burning speeds, which we refer to as generalised flame ball. The structure and stability of these flames are found to strongly depend on the direction and rate of the flow. When the flow is a source, there exist two stationary solutions, small stable flames and large unstable flames including the classical Zeldovich flame balls. When the flow is a sink, on the other hand, only large unstable flames are predicted except for sufficiently large values of the Lewis number and large negative values of the flow rate, where three flame balls exist, the medium one being stable.
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Asgyer, Abulkasem A. "Turbulent premixed impinging flames." Thesis, University of Manchester, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.488202.
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Lundqvist, Louise, and Tove Svedjewik. "”Ser jag någonting i registren, då stoppar jag” : En kvalitativ intervjustudie om svenska polisens arbete med fordonsstopp." Thesis, Högskolan i Gävle, Kriminologi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-30362.
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Syftet med studien var att undersöka vilka erfarenheter svenska poliser har av arbetet med fordonsstopp och vilka premisser de utgår från vid beslut om att kontrollera fordon i trafiken. Genom semistrukturerade intervjuer med fem poliser, framkom att de överlag hade svårt att besvara frågan gällande vilka erfarenheter de har av arbetet med fordonsstopp. Resultatet tyder på att dessa erfarenheter gör arbetet lättare för poliserna, samtidigt upplevs erfarenheterna kunna resultera i oönskade beteenden. Deras erfarenheter är också att arbetet har utvecklats med åren. Utöver lagöverträdelser, verkade inte några klargjorda premisser gällande beslut om fordonsstopp finnas. Trots detta uppgav deltagarna liknande premisser, såsom trafikförseelser, underrättelseinformation och känslan av att något inte står rätt till. I samband med fordonsstopp sker selekteringen inför beslutsfattandet genom allmän profilering och något poliser benämner byggstenar. Det förekom dock delade uppfattningar om vad som format deras premisser.The purpose of this study was to examine what experience Swedish police officers have of traffic stops and on which premises they decide to control a vehicle in traffic. Through semi structured interviews with five police officers, it appeared that they generally had difficulties in answering questions regarding their experience of traffic stops. The results indicate that these experiences seem to facilitate the work for the policemen, simultaneously the experiences appear to result in unwanted behaviour. Their experiences are that the work have developed through the years. Beyond delinquency, there seems to be no clear premises regarding decision making in traffic stops. Despite that the participants stated similar premises, among others; traffic violence, intelligence information and the feeling that something doesn't feel right. Associated with traffic stops the selection for decision making is done by general profiling and something that police officers refers to as building blocks. However, there were different opinions regarding what have formed their premises.
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Tourret, Sophie. "Prime implicate generation in equational logic." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAM006/document.
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Ce mémoire présente le résultat de mon travail de thèse sur la génération d'impliqués premiers en logique équationnelle fermée, i.e., la génération des conséquences les plus générales de formules logiques contenants des équations et des disequations entre termes sans variables. Ce mémoire est divisé en trois parties. Tout d'abord, deux calculs de génération d'impliqués sont définis. Leur complétude pour la déduction est prouvée, ce qui signifie qu'ils sont tous deux capables de générer l'ensemble des impliqués modulo redondance d'une formule équationnelle fermée. Dans une deuxième partie, une structure de données arborescente est proposée pour stocker les impliqués générés, accompagnée d'algorithmes pour déceler les redondances et couper les branches de l'arbre lorsque c'est nécessaire. Cette structure de données est adaptée aux différents types de clauses (avec et sans symboles de fonctions, avec et sans contraintes) ainsi qu'aux différentes notions de redondance utilisées dans les calculs. En effet, chaque calcul utilise un critère de redondance légèrement différent des autres. Les preuves de correction et de terminaison des algorithmes sont fournies pour chaque algorithme. Enfin, une évaluation expérimentale des différentes méthodes de génération d'impliqués premiers est réalisée. Pour cela, un prototype de ces méthodes, écrit en Ocaml est comparé à des outils de génération d'impliqués premiers récents.Les résultats de ces expériences sont utilisés pour identifier les variantes les plus efficaces des algorithmes proposés. Les résultats sont prometteurs et dans la plupart des cas, meilleurs que ceux de l'état de l'artThe work presented in this memoir deals with the generation of prime implicates in ground equational logic, i.e., of the most general consequences of formulae containing equations and disequations between ground terms.It is divided in three parts. First, two calculi that generate implicates are defined. Their deductive-completeness is proved, meaning they can both generate all the implicates up to redundancy of equational formulae.Second, a tree data structure to store the generated implicates is proposed along with algorithms to detect redundancies and prune the branches of the tree accordingly. This data structure is adapted to the different kinds of clauses (with and without function symbols, with and without constraints) and to the various formal definitions of redundancy used in the calculi since each calculus uses different -- although similar -- redundancy criteria. Termination and correction proofs are provided with each algorithm. Finally, an experimental evaluation of the different prime implicate generation methods based on research prototypes written in Ocaml is conducted including a comparison with state-of-the-art prime implicate generation tools. This experimental study is used to identify the most efficient variants of the proposed algorithms. These show promising results overstepping the state of the art
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Scholtissek, Arne [Verfasser]. "Flamelet Modeling in Composition Space for Premixed and Non-Premixed Combustion / Arne Scholtissek." München : Verlag Dr. Hut, 2019. http://d-nb.info/1181515912/34.
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Davous, Dominique. "Analyse d'un système d'enseignement supérieur : le premier cycle d'études médicales (première année et concours), recherche et expérimentation sur l'enseignement de la chimie à finalité biomédicale." Poitiers, 1987. http://www.theses.fr/1987POIT2022.
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Åberg, Jonas. "Premixed Acidic Calcium Phosphate Cements." Doctoral thesis, Uppsala universitet, Tillämpad materialvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-168650.
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Calcium phosphate cements are used in medicine to fill bone defects or give support to screws and plates in fracture fixation. The cements are formed via mixing a powder with water and the mixture harden through a dissolution-precipitation reaction. Today the cement mixing is performed in the operating room and consists of several complicated steps that need to be performed under sterile conditions. This renders the mixing a risk factor, potentially leading to harm for the patient e.g. unsatisfactory healing or infection. To reduce this risk, premixed cements have been developed using glycerol as mixing liquid. The premixed cement sets when it is exposed to body liquids. Therefore, premixed cement can be delivered to the operating room in prefilled syringes ready for use, thus eliminating the mixing step. The aim of this thesis is to describe differences between premixed and water-mixed cements and their advantages and drawbacks. The differences will be discussed based on results obtained from bench testing of specific cement properties as function of cement formulations as well as in vitro and in vivo studies. Several cement formulations were evaluated e.g. the influence of powder to liquid ratio (P/L), powder particle size and addition of water on key properties. The results showed that premixed cements have excellent handling properties and have mechanical properties similar to water-based cements. Both P/L and particle size can be used to control these properties. It was shown that small amounts of water improve certain cement properties while dry raw materials were important for long shelf life. To better understand the setting of premixed cements new methods for evaluating working time and setting of premixed cements were developed. In vivo studies showed that the formulations developed in this thesis are biocompatible, resorbable and show good tissue response in bone. This thesis concludes, that the premixed cements are a promising biomaterial with excellent handling properties and good biological response. The most important challenge for the premixed cements, in order to become commercially successful, is to obtain clinically relevant setting time and shelf life simultaneously. An increasing use of premixed cements in the clinics should shorten operation times and reduce infection rates to the benefit of both patients and medical staff.
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Mann, Kenneth R. C. "Premixed ammonia-methane-air combustion." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ62250.pdf.
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Chew, Tuan Chiong. "Aspects of premixed tubulent combustion." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292973.
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Haq, Md Zahurul. "Fundamental studies of premixed combustion." Thesis, University of Leeds, 1998. http://etheses.whiterose.ac.uk/1545/.
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The thesis comprises a fundamental study of spherical premixed flame propagation,originating at a point under both laminar and turbulent propagation. Schlieren cine photography has been employed to study laminar flame propagation, while planar mie scattering (PMS) has elucidated important aspects of turbulent flame propagation. Thrbulent flame curvature has also been studied using planar laser induced fluorescence (PLIF) images. Spherically expanding flames propagating at constant pressure have been employed to determine the unstretched laminar burning velocity and the effect of flame stretch, quantified by the associated Markstein lengths. Methane-air mixtures at initial temperatures between 300 and 400 K, and pressures between 0.1 and 1.0 MPa have been studied at equivalence ratios of 0.8, 1.0 and 1.2. Values of unstretched laminar burning velocity are correlated as functions of pressure, temperature and equivalence ratio. Two definitions of laminar burning velocity and their response to stretch due to curvature and flow strain are explored. Experimental results are compared with two sets of modeled predictions; one model considers the propagation of a spherically expanding flame using a reduced mechanism and the second considers a one dimensional flame using a full kinetic scheme. Data from the present experiments and computations are compared with those reported elsewhere. Comparisons are made with iso-octane-air mixtures and the contrast between fuels lighter and heavier than air is emphasized. Flame instability in laminar flame propagation become more pronounced at higher pressures, especially for lean and stoichiometric methane-air mixtures. Critical Peclet numbers for the onset of cellularity have been measured and related to the appropriate Markstein number. Analyses using flame photography clearly show the flame to accelerate as the instability develops, giving rise to a cellular flame structure. The underlying laws controlling the flame speed as cellularity develops have been explored. PMS images have been analysed to obtain the distributions of burned and unburned gas in turbulent flames. These have enabled turbulent burning velocities to be derived for stoichiometric methane-air at different turbulent r.m.s. velocities and initial pressures of 0.1 MPa and 0.5 MPa. A variety of ways of defining the turbulent burning velocity have been fruitfully explored. Relationships between these different burning velocities are deduced and their relationship with the turbulent flame speed derived. The deduced relationships have also been verified experimentally. Finally, distributions of flame curvature in turbulent flames have been measured experimentally using PMS and PLIF. The variance of the distribution increases with increase in the r.m.s. turbulent velocity and decrease in the Markstein number. Reasons for these effects are suggested.
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Couture, Karine. "Etude de la métallation en série diazinique 1) premier échange iode-lithium avec les alkylamidures de lithium 2) amination électrophile 3) première métallation sans groupe directeur." Rouen, 1995. http://www.theses.fr/1995ROUES020.
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Ce travail consiste en l'étude de la réaction de métallation en série diazinique. Dans une première partie, nous avons pu mettre en évidence pour la première fois en série diazinique, un mécanisme d'halogen-dance avec migration de l'iode. De plus, nous avons pu observer pour la première fois dans cette série, un exceptionnel échange iode-métal avec les alkylamidures de lithium. Cette réaction a été appliquée à la synthèse de leshmaniacides. Dans une seconde partie, nous avons mis au point l'amination électrophile par métallation en série diazinique. Cette réaction d'amination a été appliquée à la synthèse de molécules biologiquement actives et nous a permis d'accéder à un azaanalogue de la Névirapine ainsi qu'à des précurseurs de sulfamides connus. Dans une troisième partie, nous avons tenté d'élargir la gamme des groupes ortho-directeurs en série pyrimidinique (NHCOtBu, CONHtBu). Dans la dernière partie, une nouvelle fonctionnalisation directe des diazines sans groupe ortho-directeur a été réalisée avec succès
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Baita, Chakib. "Le Premier ministre au Maroc." Lille 3 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb37595665h.
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Baita, Chakib. "Le Premier ministre au Maroc." Paris 12, 1986. http://www.theses.fr/1986PA120202.
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L'etude de l'institution du premier ministre a ete envisagee a un double point de vue; d'abord sur le plan politique et ensuite sur le plan administratif. L'action du premier ministre en tant qu'autorite politique, se revele limitee et etroitement controlee par le roi qui constitue l'organe supreme du systeme constitutionnel marocain auquel sont subordonnees toutes les institutions et notamment celle du premier ministre. La subordination est la donnee essentielle du statut du premier ministre; elle est la consequence directe de la suprematie royale qui ne peut tolerer l'affirmation d'une autre autorite au risque de perdre sa preeminence. La subordination du premier ministre est par ailleurs multiple; en effet avant de devenir legale et de recevoir une consecration constitutionnelle, elle a ete coutumiere dans la mesure ou elle decoule de l'heritage et de la tradition; elle est a la fois organique et fonctionnelle. Toutefois, si le premier ministre est un subordonne, il est par ailleurs un intermediaire privilegie. Il est l'homme de confiance du roi et sa situation de dependance vis-a-vis de ce dernier est compensee par une preeminence sur les membres du gouvernement et d'une facon generale sur le plan administratif. Dans ce dernier domaine, le premier ministre detient des prerogatives importantes et dispose de nombreux services lui permettant de diriger, de controler et de coordonner l'appareil gouvernemental et administratif. A travers l'etude de l'action administrative du premier ministre, celuici apparait comme le delegataire du domaine administratif et comme une structure de coordinationThe study of the prime minister's institution has been considered on a double point of view; firstly, on a political view and secondly on a administrative one. The action of the prime minister as a political authority reveals limited and strongly controled by the king who constitutes the highest part of the maroccan constitutional system to which is subordonate all the institutions and especially that of the prime minister. The subordination is the main point of the prime minister status. It is the direct consequence of the royal supremacy which cannot tolerate the affirmation of another authority at the risk of losing its supremacy. The subordination of the prime minister is multiple. Indeed, before becoming legal and receiving a constitutional ratification, it has been as so far it proceeds from the legacy and the tradition, it is at the same time organical and fonctional. However, if the prime minister is a subordinate, he is also a privileged middleman. He is a trustworthy man of the king and his situation of dependance regarding him is compensated by a supremacy on governmental members and as a whole on the administrative view. In this field, the prime minister has get large numerous services allowing him to manage, to control and to coordinate the administrative and governmental system. Through the study of the administrative action of the prime minister, his is appearing as the delegater of the administrative field and as a coordination structure
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Bastit, Agnès. "Origene exegete du premier evangile." Paris 4, 1992. http://www.theses.fr/1992PA040028.
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Cette these, intitulee "origene, exegete du premier evangile", comprend deux parties. L'une, sous le titre de "dialectique et poetique du recit evangelique. Etude sur le genre du commentaire savant et ses rapports avec l'exegese evangelique d'apres les tomes sur matthieu d'origene ", est une etude consacree au commentaire grec d'origene sur l'evangile de matthieu, sous le double aspect d'une analyse formelle, litteraire, et d'une recherche sur la specificite de l'exegese origenienne par rapport a la tradition chretienne anterieure de lecture du premier evangile. L'autre, sous le titre de "le tome xii des commentaires d'origene sur l'evangile selon matthieu", apres une etude de la transmission de l'oeuvre en general, propose un projet d'etablissement du texte pour le tome xii, accompagne d'une traduction francaise, d'un commentaire et d'un indexTHIS THESIS, UNDER THE TITLE OF "ORIGEN AS EXEGET OF THE FIRST GOSPEL" IS DIVIDED IN TWO PARTS : THE FIRST ONE, "DIALECTIC AND POECTICS OF THE EVANGELICAL NARRATIVE. A STUDY ABOUT THE SCHOLARLY COMMENTARY AND ITS RELATIONS with THE EXEGESIS OF THE GOSPEL", IS A STUDY DEDICATED TO THE GREEK COMMENTARY OF ORIGEN ON THE GOSPEL OF MATTHEW, THROUGH A FORMAL AND LITERARY ANALYSIS AS WELL AS A RESEARCH ABOUT THE SPECIFICITY OF ORIGEN'S EXEGESIS COMPARED WITH THE EARLY CHRISTIAN TRADITION OF THE READING OF THE FIRST GOSPEL. THE OTHER ONE, "THE TWELFTH TOME OF ORIGEN'S COMMENTARY ON MATTHEW", AFTER A STUDY ABOUT THE TRANSMISSION OF THIS BOOKS, SUGGESTED A PROJECT OF TEXTUAL CRITICISM OF THE TWELTH TOME, TOGETHER WITH A FRENCH TRANSLATION, A COMMENTARY AND A INDEX
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Charoenthanavat, Kriengkrai. "Le Premier ministre en Thaïlande." Strasbourg 3, 1996. http://www.theses.fr/1996STR30023.
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Dotés d'un régime parlementaire, la plupart des pays démocratiques actuels ont connu un renforcement du pouvoir exécutif, et plus particulièrement du gouvernement responsable devant le parlement. La Thailande est un pays dit "démocratique" qui pratique le régime parlementaire. Pourtant la démocratie de ce pays est interrompue, de temps en temps, par l'armée. Cette situation apparaît toujours quand les partis politiques sont impuissants à gérer la politique du pays à cause de leur division. Par conséquent, la politique et la démocratie de ce pays sont instables. Comme disent les technocrates, elles sont dans un "cercle vicieux". Le gouvernement dépend du groupe politiquement puissant de chaque époque. Le premier ministre est considéré comme le plus important et plus puissant des ministres. C'est le premier des ministres. En effet, les outils constitutionnels et légaux lui ont permis d'acquérir de plus en plus de pouvoir et lui ont permis d'administrer le pays. Il détient des pouvoirs étendus. C'est pourquoi il est devenu "le chef puissant de l'exécutif" de l'état. Cependant, à cause du changement politique, de la pression issue de la division entre les ministres et de l'influence de l'armée, il est parfois le médiateur politique, plutôt que le chef de l'exécutif, pour maintenir sa stabilité. Cette recherche a porté sur l'évolution, le choix, la nomination et les pouvoirs du premier ministre de la Thaïlande. Ces différents points sont liés aux évènements politiques qui expliquent comment le premier ministre obtient ce poste, comment il gouverne le pays, et pourquoi il est parfois sous la direction de certains groupes puissantsEndowed with a parliamentary system, nowadays most of the democratic countries accepted a reinforcement of the executif power, especially the responsibility of the government to the parliament. Thailand, known as a "democratic" country, practices the parliamentary system. However the democracy of this country is always interrupted by the military. This situation appeared when the political parties are ineffectual to manage the politic because of theirs divisions. Consequently the politic and the democracy of this country are unsteady. They are always in the "vicious cercle", called by the technocrats. The government depends on the strong political group in each time. The prime minister is considered to be the most important and the most powerful person among the ministers. He is the first among the others. Indeed the mechanisms of the constitution and the laws allow him to have much more power and to carry out the administration of the state. He is in possession of the extensive power. Consequently he becomes "the strong chief executive" of the state. Nevertheless owing to the changing of the politic, the pressure of the division among the ministers and the influence of the military, he sometimes becomes politic mediator rather than the chief executive by the reason of keeping his stability. This research concerns the evolution, the choiceness, the nomination and the power of the prime minister of thailand. These different points are linked by the political events which explain how the prime minister obtains this post, how he carries out the administration of the state and for what reason he is sometimes in the control of some powerful groups
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Undapalli, Satish. "Large eddy simulation of premixed and non-premixed combustion in a stagnation point reverse flow combustor." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22625.
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Thesis (Ph. D.)--Aerospace Engineering, Georgia Institute of Technology, 2008.Committee Chair: Suresh, Menon; Committee Member: Ben T, Zinn; Committee Member: Jeff Jagoda; Committee Member: Jerry Seitzman; Committee Member: Thorsten Stoesser.
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JI, BYONGMOK. "Recherche sur les societes de l'asie du nord-est au premier age des metaux - premiers metallurgistes et culture metallique representee par la dague en forme de "pip'a" -." Paris 7, 1996. http://www.theses.fr/1996PA070031.
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Du point de vue metallurgique, les cultures de l'age du bronze de la chine centrale, du nord de la chine et de la siberie, jouerent un role important quant a l'apparition de la culture metallurgique dans la region du nord-est de l'asie. Durant le premier age des metaux, il exista deux cultures metalliques differentes dans la region de l'asie du nord-est, separees par la limite naturelle du fleuve liao(he). Dans la zone occidentale du fleuve, l'influence de la chine centrale, du nord de la chine et de la siberie est manifestee dans cette culture. Par contre, dans l'aire orientale du fleuve liao(he), le contexte metallique est plus simple. Il est caracterise par la presence d'une dague en forme de "pip'a" (luth) et de sepultures de pierres. D'apres les analyses morphologiques, ces dagues sont classees en quatre types. Durant la premiere periode, la ciste et la dague en forme typique de "pip'a" etaient les principales caracteristiques dans cette region. Depuis le debut de la deuxieme periode, la ciste a ete remplacee peu a peu par la tombe en fosse. Les caracteres morphologiques des dagues en forme de "pip'a" evoluerent egalement au cours des differentes periodes.
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Faure, Nelly. "Entre historicisme et modernité : les châteaux construits ou remaniés dans l'Allier, le Cantal et le Puy-de-Dôme, entre le Premier Empire et la Première Guerre mondiale." Thesis, Clermont-Ferrand 2, 2014. http://www.theses.fr/2014CLF20014/document.
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En mettant fin aux privilèges et à une société d’ordres, la Révolution aurait dû vouer le château à la ruine, ne le laissant subsister dans le paysage que comme les vestiges d’un temps révolu. Mais au contraire, le XIXe siècle devient un véritable âge d’or des châteaux, en France comme dans toute une partie de l’Europe. À travers la France, les constructions, les restaurations et les remaniements de châteaux se comptent par milliers, sous le double effet du repli de la noblesse sur ses terres et de l’essor et de l’enrichissement de la bourgeoisie. Dans l’Allier, le Cantal et le Puy-de-Dôme 464 chantiers et projets voient le jour sous l’impulsion de familles de la vieille noblesse désireuses de réparer sur leur demeure les outrages du temps et de la Révolution et de bourgeois fortunés soucieux d’avoir une résidence prestigieuse, témoin de leur ascension sociale. Au XIXe siècle, on pose un nouveau regard sur le Moyen Âge et le château des siècles passés fait rêver. L’architecture doit s’inspirer des styles historicistes, parfois d’origine lointaine, tout en offrant un intérieur adapté au mode de vie et aux aspirations au confort des châtelains. Certains architectes se spécialisent pour satisfaire ces commandes entre historicisme et modernitéAs the French Revolution put an end to privileges and the hierarchical division of society, castles seemed meant to disappear or survive only as remains of a bygone era. But the 19th century actually turned out to be a golden age for them – both in France and in many countries in Europe. In France, countless castles were built or overhauled, as the nobility returned to their lands and the bourgeoisie grew in power and wealth. In the three French départements of Allier, Cantal and Puy-de-Dôme, no less then 464 projects or actual construction works were launched. They originated either from ancient noble families wishing to erase the damages of time and History on their properties or from wealthy bourgeois willing to own high-profile mansions that would be of testimony of their social uplift. The 19th century was also a period where the Middle Ages was re-discovered and ancient castles became attractive again. Architectural trends were influenced by historicism, sometimes exotic styles, while interior design had to suit the lifestyle and need for comfort of the landlords. Some architects specialised in such projects, both historicist and modern
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Shelil, Nasser. "Flashback studies with premixed swirl combustion." Thesis, Cardiff University, 2009. http://orca.cf.ac.uk/55494/.
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The important conclusion was reached that when combusting H2/CH 4 fuel mixes flashback behaviour approaches that of pure methane for equivalence ratios less than about 0.65, all pressures investigated up to 7 bara and air inlet temperatures of 300 and 473K. Significant deleterious changes in flashback behaviour for H2/CH4 fuel mixes occurred for air inlet temperatures of 673K, although operation at weak equivalence ratios less than 0.65 was still beneficial.
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Patel, Samir N. D. H. "Modelling of premixed turbulent propagating flames." Thesis, Loughborough University, 2001. https://dspace.lboro.ac.uk/2134/6810.
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Combustion has an active role in our modern lives as we continue to exploit its potential for many of our requirements. For example, its use to produce electricity and to power land, air and space transport vehicles. Increasing competition from the onset of the Industrial Revolution has led to a greater emphasis on improving technology. Furthermore, the ongoing issue of global warming has led to government legislation on emissions. These problems have led to increasing interest in gaining fundamental critical details on flow and combustion in simple and complex engineering geometries. Over the past twenty to thirty years numerical methods have demonstrated their success at obtaining information on flow and combustion. However, there is a continuing need to develop many of the components comprising a numerical method. The work reported here stems from the modelling of turbulent premixed flames. Turbulent premixed flames is a mode of combustion where the fuel and air mix before reacting. Such a combustion mode is present in spark ignition (SI) and gas turbine (GT) engines, and in explosions. Modelling of the combustion process within these practical applications can provide useful information. For example, in aiding the design of the piston bowl and the combustion chamber of SI and GT engines, respectively. Furthermore, the simulation of explosions can result in safer designs for fuel storage and supply facilities. A central parameter to be modelled in turbulent premixed flame propagation is the rate of chemical reaction. This is a crucial parameter since it controls the rate of flame propagation, flame structure, and resulting pressure history. However, to date the challenge of accurately modelling the rate of chemical reaction over a range of turbulence conditions remains. Therefore, in this thesis, mathematical models for the mean rate of reaction are examined, developed, and validated against time-resolved experimental data. The aim of the work is to improve the modelling of the mean rate of reaction in order to achieve closer agreement with available experimental results on rates of flame propagation, flame structure, and pressure history. Recent, practical and numerical experiments have provided support for algebraic and transport equation models for the flame surface area to volume ratio to model the mean rate of reaction. Here, these models are examined and developed with one-, two-, and three-dimensional computational fluid dynamics (CFD) calculations. The simulations were carried out using both an in-house code (Turbulent Reacting Flows, TRF) and a commercially available CFD code (FIRE). The TRF code was used to investigate the ability of existing and developed models to accurately predict turbulent burning velocity. The models were then validated further by simulating turbulent flame propagation in two combustion chamber configurations with built-in solid obstacles. Hence verifying the models for different turbulence and geometry conditions. A nonlinear eddy-viscosity model was implemented into the TRF code to assess the significance of turbulence modelling in turbulent premixed flames. Finally, the developed models were implemented in the FIRE code to carry out three-dimensional calculations to verify reproducibility of the TRF code results and to investigate secondary flow effects. Two reaction rate models were developed namely the algebraic (BML) and transport flame surface density (FSD) models. Both BML and FSD models yield plausible results for flame propagation in turbulent premixed combustion. However, modifications to the BML model were required for low turbulence conditions, and superior results were obtained with the FSD model. Both models struggled in capturing the interaction between flame and turbulent wakes behind obstacles when the standard linear eddy-viscosity turbulence was used. However, the application of a non-linear version of the eddy-viscosity model yields improved results for flame structure and speed around the obstacle, highlighting the importance of the turbulence model. The 3D calculations using the developed combustion model show good reproducibility of the 2D findings. Furthermore, the flame propagation, pressure history, and flame speed results are found to be in plausible agreement with the experimental data. It is shown that secondary flow mainly has the effect of increasing the rate of flame propagation in the single obstacle combustion chamber, and that the influence of secondary flow is dominant in the turbulent wake behind the obstacles.
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Kostiuk, Larry William. "Premixed turbulent combustion in counterflowing streams." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305530.
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Ma, Yi Pearlman Howard. "High-Lewis number premixed flame instabilities /." Philadelphia, Pa. : Drexel University, 2009. http://hdl.handle.net/1860/3127.
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Ebieto, Celestine. "Dynamics of premixed flames in tube." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/19521/.
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Experimental work is reported for premixed flames propagating in tubes. The flames were ignited with a pilot flame and the flame propagation captured with high-speed cameras. Initial measurements were performed characterising the rig. These included investigations of the end configuration (open, closed, orifice plate) and whether the tube was horizontal or vertical. For horizontal tube open at both ends, the pressure signal of the propagating flame was recorded and the flame temperature distribution along the tube length was found by observation of a thin silicon carbide filament. The flame propagated steadily immediately after ignition with a curved front, then was subjected to oscillations at the middle of the tube. At the end of the tube, it regained its stability. The pressure and temperature of the propagating flame were highest at the middle point where the flame oscillated. Methane-air flames enriched with hydrogen were studied. As the hydrogen concentration was increased the acoustic pressure initially increased and then decreased this was found to be associated with the presence of Rayleigh-Taylor instabilities. For downwardly propagating flames to a closed end, methane and propane were studied. The flames initially propagated steadily, then at approximately a third of the way down the tube, the primary acoustic oscillation sets in resulting to change in the flame shape. This was then followed by a plateau of variable length before a more violent secondary acoustic oscillation. In some circumstances, flames were observed to rotate due to the primary acoustic instability. Some of the flames were subjected to Rayleigh Taylor instabilities associated with large pressure oscillations. The flame front position growth rate for both methane and propane were similar despite the differences in the fuels. There was a strong correlation between the flame oscillations and changes in CH* and C2* as well as the flame surface area.
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Chen, Zhi. "Simulation of partially premixed turbulent flames." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/263015.
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This work numerically investigates the turbulent partially premixed flames, which are ubiquitous in combustion powered devices. This combustion mode involves many physical complexities such as flame propagation in unevenly premixed mixture of fuel and oxidiser, turbulence/flame interaction in presence of mixture fraction gradients, triple flame configuration, etc. The fundamental mechanisms of these physical processes are yet to be further understood, posing significant modelling challenges. These issues are addressed in this thesis using a presumed joint probability density function (PDF) approach with both Reynolds Averaged Navier Stokes (RANS) and Large Eddy Simulation (LES) methodologies. This joint PDF is described by a parameter, mixture fraction, describing mixing and a reaction parameter, progress variable. The laminar flamelet concept is adopted to decouple chemistry and turbulence calculations for high computational efficiency. This modelling framework is validated using two experimental test cases in this study including a canonical lifted jet flame and a practical swirling flame, both exhibiting strong partial premixing features. The simulation results obtained for these validation cases show a robust model performance for a broad range of flow and mixing conditions with an attractive computational cost for practical interests. For the lifted jet flame case, two-dimensional (2D) axisymmetric steady RANS approach is used to compute the flame lift-off height showing very good agreement with the experimental measurements for a range of jet velocities and air-dilution levels. However, a substantial difference is found between the 2D unsteady RANS (URANS) results and experimental data for the flame transient evolution from its initial ignition to final stabilisation. The comparison for this transient evolution is improved significantly in the 3D URANS simulations suggesting that the third physical dimension, the azimuthal direction, plays an important role during the flame transient evolution. The following LES study further shows that the flame most-leading point appears to be in different azimuthal positions exhibiting a spiral -like trajectory as the flame propagates upstream towards the final lift-off height. The temporal variation of this leading point during this process is captured very well by the LES model in comparison with the experimental data. The validity of this LES model is then further assessed for a confined swirling flame with practical flow conditions. The simulation results are compared against an extensive experimental dataset including velocity, mixture fraction, temperature and major species mass fraction measurements, showing an overall good agreement at various locations inside the combustion chamber. The intermediate species mass fractions are also predicted reasonably well by the LES model despite that a general over-estimation is observed. Moreover, it is found that in the transport equation for the SGS variance of progress variable, the reaction and dissipation terms are predominant, substantially greater than the terms representing turbulent diffusion and production processes. Furthermore, the statistical correlation between mixture fraction and progress variable is found to be important for the RANS closure. However, this correlation is observed to be negligible for the sub-grid scale (SGS) of LES showing reasonably good model predictions for both simulated experimental configurations.
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Keays, John F. "Large eddy simulation of premixed combustion." Thesis, Imperial College London, 2007. http://hdl.handle.net/10044/1/11284.
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Lim, Kian Min. "DNS of inhomogeneous reactants premixed combustion." Thesis, University of Cambridge, 2015. https://www.repository.cam.ac.uk/handle/1810/247342.
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The search for clean and efficient combustors is motivated by the increasingly stringent emissions regulations. New gas turbine engines are designed to operate under lean conditions with inhomogeneous reactants to ensure cleanliness and stability of the combustion. This ushers in a new mode of combustion, called the inhomogeneous reactants premixed combustion. The present study investigates the effects of inhomogeneous reactants on premixed combustion, specifically on the interactions of an initially planar flame with field of inhomogeneous reactants. Unsteady and unstrained laminar methane-air flames are studied in one- and two-dimensional simulations to investigate the effects of normally and tangentially (to the flame surface) stratified reactants. A three-dimensional DNS of turbulent inhomogeneous reactants premixed combustion is performed to extend the investigation into turbulent flames. The methaneair combustion is represented by a complex chemical reaction mechanism with 18 species and 68 steps. The flame surface density (FSD) and displacement speed S_d have been used as the framework to analyse the inhomogeneous reactants premixed flame. The flames are characterised by an isosurface of reaction progress variable. The unsteady flames are compared to the steady laminar unstrained reference case. An equivalence ratio dip is observed in all simulations and it can serve as a marker for the premixed flame. The dip is attributed to the preferential diffusion of carbon- and hydrogen- containing species. Hysteresis of S_d is observed in the unsteady and unstrained laminar flames that propagate into normally stratified reactants. Stoichiometric flames propagating into lean mixture have a larger S_d than lean flames propagating into stoichiometric mixtures. The cross-dissipation term contribution to S_d is small (~~10%) but its contribution to the hysteresis of S_d is not (~~50%). Differential propagation of the flame surface is observed in the laminar flame that propagates into tangentially stratified reactants. Stretch on the flame surface is induced by the differential propagation, which in turn increases the flame surface area.
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Jörg, Christoph [Verfasser]. "Experimental Investigation and Spectral Modeling of Turbulent Combustion Noise from Premixed and Non-Premixed Flames / Christoph Jörg." München : Verlag Dr. Hut, 2015. http://d-nb.info/1079768122/34.
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Franklin, Michael C. "Transfer Spending in the English Premier League Transfer Market: Are Elite Premier League Teams Spending Excessively?" Scholarship @ Claremont, 2013. http://scholarship.claremont.edu/cmc_theses/757.
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Transfer spending among Premier League teams has increased drastically since the inception of the league. Over the past decade, extremely wealthy owners have begun purchasing majority stakes in clubs and spending recklessly to accumulate as much talent as possible. This paper aims to examine whether such exorbitant spending is effective financially and whether it improves the clubs competitively. Data is gathered from Deloitte’s Annual Reviews of Football Finance. I conclude that spending at such high levels does not improve on-field performance, which is consistent among clubs in the past decade and the elite clubs across all seasons.
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Perron, Danielle. "Le messianisme juif au premier siècle /." Trois-Rivières : Université du Québec à Trois-Rivières, 2004. http://www.uqtr.ca/biblio/notice/resume/18446574R.pdf.
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Holmberg, Erik. "Antal hörnor i Premier League-matcher." Thesis, Uppsala universitet, Statistiska institutionen, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-219232.
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Dulaey, Martine. "Victorin de poetovio, premier exegete latin." Paris 4, 1987. http://www.theses.fr/1987PA040285.
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Victorin, eveque de poetovio (ptuj, en yougoslavie) dans la seconde moitie du 3eme siecle est le premier latin a consacrer des traites entiers a l'exegese de la bible : jerome, en une liste dont il precise qu'elle n'est pas exhaustive, enumere sept opuscules. La presente these passe en revue tous les temoignages anciens sur l'oeuvre et procede a une analyse detaillee des deux ouvrages parvenus jusqu'a nous (un commentaire sur l'apocalypse et le petit traite sur la construction du monde), ainsi que de quelques fragments imputables a l'auteur. On met ainsi en lumiere d'une part la vaste culture chretienne de l'exegete, nourri surtout des grecs (notamment irenee, hippolyte et origene), mais aussi des latins (tertullien, cyprien. . . ), et d'autre part, la large audience dont a beneficie son oeuvre aux quatrieme et cinquieme siecles avant d'etre eclipsee par celle des peres de l'age d'or qui s'en sont approprie la substance. Victorinus, the bishof of poetovio (ptuj, yugoslavia) in the iind half of the third century, was the first latin who wrote biblical commentaries. St jerome gives the titles of seven treatises, the list not being exhaustive. The present thesis examines all the ancient testimonies concerning the works of victorinus, and gives a detailed analysis of the two surviving ones (a commentary on revelation and a short treatise on the creation), as well as a few fragments we can attribute to the author. From this study, we can emphasise the exeget's vast christian culture, for he drew principally on greek writers (such as irenaeus, hippolyt and origene), but also on the latin writers (tertullian, cyprian. . . ) and on the other hand the large influence of his work during the fourth and fifth centuries, before being eclipsed by that of the fathers of the golden age, who assimilated most of his matter.
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ATALAY, HAN. "Premier spectrometre portable polyvalent nouvelle generation." Nantes, 1995. http://www.theses.fr/1995NANT2126.
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Jusqu'a une epoque recente, les systemes de spectroscopie complexes n'etaient jamais utilises a l'exterieur des laboratoires de recherche. Grace a des avancees technologiques importantes notamment en volume d'elements optiques holographiques, de detecteurs ccd, des lasers ou sources de lumiere qht (quartz, tyngsten halogene), la spectroscopie css ( ) a emerge comme etant un outil analytique important et pratique. Le h. A. N. (hyperfine analytical network) est le premier d'une generation nouvelle de spectrometre compacte, portable, tout integre, utilise comme analyseur multi-fonctions. Le dispositif h. A. N. Permet a l'utilisateur de tirer d'avantage de benefices dans plusieurs domaines incluant les suivants : diffusion raman, transmittance et reflectance, absorbance, fluorescence et colorimetrie.
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Courjou, Évelyne. "Le toucher, premier et ultime dialogue." Marne-la-Vallée, 2004. http://www.theses.fr/2004MARN0216.
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Traiter du toucher, en première approche, peut sembler banal. Mais il n’en est rien ! C’est un vaste sujet qui dépasse notre dimension humaine pour nous faire «saisir » l’immatérialité des concepts métaphysiques et en particulier la mort. Le toucher, un sens vital, joue un rôle fondamental dans la préservation de l’espèce humaine, dans l’apprentissage de la personnalité, et dans bien d’autres domaines encore. Qu'il soit baiser, massage ou simple contact, le toucher véhicule un ensemble de messages infra-verbaux qui tisse un lien relationnel indispensable tout au long de la vie et qui prend une intensité particulière à l’approche de l’indicible. Sens éminemment humain, il s’oppose à une technologie sans cesse plus galopante. Il entre aussi en dualité avec un monde d’images impalpables qui tend à déréaliser l’environnement humain. Le mort et la mort passent fréquemment dans le domaine de l’imaginaire. Aussi le soignant fait-il partie de ce rare pourcentage de la population à être souvent confronté à l’indicible. Quels sont les ressentis de ceux qui touchent le mort et comment appréhendent-ils la mort ? Une sorte de relation magique s’établit entre le vivant et la mort par le toucher, symbole de vie par excellence. Comment, au fil des siècles et de nos jours, se positionne la perception tactile face à l’ensemble des représentations mortelles que s’en fait l’homme ? Nombre d’individus souhaitent connaître l’immortalité. Mais cette espérance varie selon les êtres humains : immortalité matérielle sensorielle palpable, immortalité virtuelle, immortalité immatérielle et spirituelle, réincarnation, etc. Selon ces différentes aspirations il y aura dévalorisation ou non de la qualité tactile et par voie de conséquence du corps humain
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Bernier, Claudine. "L'architectonique du "Premier jardin" d'Anne Hébert." Thèse, Université du Québec à Trois-Rivières, 1992. http://depot-e.uqtr.ca/5387/1/000598068.pdf.
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Perron, Danielle. "Le messianisme juif au premier siècle." Thèse, Université du Québec à Trois-Rivières, 2004. http://depot-e.uqtr.ca/1640/1/000120979.pdf.
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Vasilišin, Maroš. "Inteligentní manažer hry Fantasy Premier League." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2020. http://www.nusl.cz/ntk/nusl-417274.
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Hra Fantasy Premier League poskytuje miliónom hráčov po celom svete možnosť stať sa na chvíľu manažérom svojho vlastného klubu. Výsledky a bodové ohodnotenie v hre závisia na správnom predvídaní, ako sa budú hráči chovať v skutočných futbalových zápasoch. Ak by pri tomto rozhodovaní pomáhal software na predikciu a analýzu budúcich výkonov hráčov, výsledky v hre sa môžu rapídne zlepšiť. Táto diplomová práca sa zaoberá návrhom a implementáciou predikčného modelu, ktorý využíva neurónové siete na predikcie časových radov počas celej sezóny v hre. Boli použité metódy na spracovanie dát o hráčoch a kluboch za posledné 4 sezóny. Výkonnosť a presnosť predikčných metód boli testované na dátach z poslednej sezóny Premier League a predikcie algoritmu sa vo väčšine prípadov blížili realite. Ak by sa užívateľ držal predikčného modelu v hre stopercentne, získal by väčší počet bodov ako bežný hráč, ktorý žiadny predikčný model nepoužíva.