Cette Thèse s'intéresse au thème de la Lamentation en Italie de la fin du 13e à la fin du 16e. L'approche vise à analyser et interpréter les contigüités qui unissent la Vierge, Madeleine et Jean - entre eux et au Christ mort. La première partie revient sur l'apparition du thème et sur sa diffusion. Nous posons ensuite la question de sa définition. La deuxième montre que, loin de se limiter à l'image, les condensations peuvent se jouer dans l'ensemble du « réseau figuratif ». Au lieu de ne montrer que la scène qu'elles donnent à voir, certaines Lamentations évoquent d'autres épisodes de l'histoire du Salut. C'est le premier niveau des contiguïtés plastiques. La troisième resserre la réflexion et se concentre sur les Lamentations. Cette partie propose un second niveau d'analyse aux contiguïtés. Grâce à différents procédés, des associations plastiques s'instaurent entre la Vierge, Madeleine, Jean et le Christ. La dernière s'intéresse à toutes les contiguïtés. Nous défendons l'hypothèse selon laquelle les personnages qui entourent le cadavre peuvent se comprendre comme l'Ecclesia. La constitution de corpus en forme d'hyperthèmes nous permet de vérifier l'hypothèse. / This Thesis deals with the iconographic theme of the Lamentation around the dead Christ in Italy from the end of the thirteenth century to the end of the sixteenth. It analyzes the « contiguïtés » between the Virgin Mary, Mary Magdalene and John. The first part shows the historic appearance and the circulation of the theme. Then, the question its definition is put. The second shows that, far from limiting itself to the very image, the iconographic condensations can also deceive in the whole of the « representational network ». Instead of showing only the scene which they give to see, certain Lamentations also evoke the order episodes of the Redemption. It is the first level of the « contiguïtés plastiques ». The third tightens the reflection and concentrates only on the Lamentations. This part so proposes a second level of analysis in the « contiguïtés plastiques ». The fourth is interested of all the « contiguïtés » uniting the Virgin, Magdalene and John between them and to the Christ in the Lamentations. We defend the hypothesis according to which the characters who surround the corpse can be understanding as Ecclesia. The constitution of corpus in the shape of hyperthemes allows us to verify the hypothesis.

Made available in DSpace on 2014-06-11T19:32:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-02-26Bitstream added on 2014-06-13T20:27:16Z : No. of bitstreams: 1 silva_ley_dr_ift.pdf: 4929051 bytes, checksum: ca9589a1164e8d2361903c516c6ac865 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Nesta tese estudamos conceitos básicos de um condensado de Bose-Einstein (BEC) e sua extensão para sistemas com propriedades mais exóticas, incluindo misturas de dois componentes, com algumas características interessantes encontradas devido à interação entre espécies, e condensados de átomos com forte momento (magnético) dipolar, nos quais a interação dipolo-dipolo (anisotrópica e de longo-alcance), abre novas possibilidades de pesquisa na procura por desconhecidas e fascinantes características para gases atômicos ultra-frios. Mostramos o modelo de campo-médio para misturas de dois BECs interagindo através do potencial de contato e da interação dipolar de longo-alcance empregando termos não lineares de inter e intra-espécies. Aplicamos este modelo em sistemas binários com diferentes armadilhas em que um deles ou ambos podem ser dipolares. Especificamente, estudamos as características físicas de uma mistura de dois BECs - com e sem interação dipolar -, a formação (e dinâmica) de bright solitons para um BEC dipolar, algumas propriedades interessantes para um BEC dipolar no limite de interação forte, e as características de um BEC dipolar quase-livre vinculado à um outro BEC não dipolar confinado numa armadilha magnética. Apresentamos nossos resultados numéricos usando gráficos de densidade, diagramas de fase, de formação de estruturas nas densidades ou a dinâmica dos sistemas, entre outros. Sempre que possível, nossos resultados serão associados com quantidades usadas em técnicas experimentais através de um tipo específico de átomo, o número de partículas, os valores dos parâmetros de interação, a anisotropia da armadilha ou outras quantidades relacionadas com observáveis experimentais / We described the basic ideas of Bose-Einstein condensation (BEC), and then we focused our study on extensions to more exotic condensates including mixtures of two components, where interesting characteristics are found due to the interspecies interaction, and magnetic dipolar gases, which with their ansiotropic long-range dipolar interaction have opened up new avenues of research into cold atoms, in a quest for novel and fascinating features. In this thesis, we present the mean-field model for the binary BEC interacting two-componente mixtures of dipolar and nondipolar BECs, the formation and dynamics of bright solitons, the strong coupling domain for dipolar BECS, and the features of an untrapped bound dipolar droplet in a trapped nondipolar condensate. Our numerical results are presented in density plots, stability, phase plots, structure formartion in densities, breathing oscillation, and more. However, these solutions, whenever possible, are associated with quantities widely handled in experimental techniques, theough a specific types of atoms, number of particles, values of parameters of interaction or the anisotropy of trap, and others quantities related to experimental observables

abstract: Durable, cost-effective, and environmentally friendly anti-icing methods are desired to reduce the icing hazard in many different industrial areas including transportation systems, power plants, power transmission, as well as offshore oil and gas production. In contrast to traditional passive anti-icing surfaces, this thesis work introduces an anti-icing coating that responds to different icing conditions by releasing an antifreeze liquid. It consists of an outer porous superhydrophobic epidermis and a wick-like underlying dermis that is infused with the antifreeze liquid. This bi-layer coating prevents accumulation of frost, freezing fog, and freezing rain, while conventional anti-icing surfaces typically work only in one of these conditions. The bi-layer coating also delays condensation on the exterior surface at least ten times longer than identical system without antifreeze. It is demonstrated that the significant delay in condensation onset is due to the integral humidity sink effect posed by the hygroscopic antifreeze liquid infused in the porous structure. This effect significantly alters the water vapor concentration field at the coating surface, which delays nucleation of drops and ice. It was demonstrated that with a proper design of the environmental chamber the size of the region of inhibited condensation and condensation frosting around an isolated pore, as well as periodically spaced pores, filled by propylene glycol can be quantitatively predicted from quasi-steady state water vapor concentration field. Theoretical analysis and experiments revealed that the inhibition of nucleation is governed by only two non-dimensional geometrical parameters: the pore size relative to the unit cell size and the ratio of the unit cell size to the thickness of the boundary layer. It is demonstrated that by switching the size of the pores from millimeters to nanometers, a dramatic depression of the nucleation onset temperature, as well as significantly greater delay in nucleation onset can be achieved. / Dissertation/Thesis / Doctoral Dissertation Mechanical Engineering 2017

Orientador: Bruto Max Pimentel Escobar / Coorientador: Rodolfo Alvan Casana Sifuentes / Banca: Silvio Roberto de Azevedo Salinas / Banca: Antônio Edson Gonçalves / Banca: Victo dos Santos Filho / Banca: Abraham Hirsz Zimerman / Resumo: Estudamos a Teoria de DKP massiva à Temperatura Finita. Primeiramente, analisamos a sua estrutura de vínculos e mostramos que ela é uma teoria de vínculos de segunda classe. Em seguida, após a introdução da Função de Partição via integração funcional, estudamos a Condensação de Bose-Einstein (CBE) e mostramos que a teoria em estudo apresenta o modo zero, fundamental para a existência da CBE, de maneira simples e clara. A análise mostra resultados idênticos aos proporcionados pelas teorias de KGF e Proca. O problema da equivalência é também estudada para o caso de termos temperatura diferente de zero. Provamos, de forma geral, que as funções de Green fotônicas das teorias de DKP e KGF coincidem. Também, calculamos a polarização do vácuo no nível de um loop, obtendo-se as contribuições dependentes e independentes da Temperatura tal como as obtidas via a teoria KGF / Abstract: We study the massive DKP theory at Finite Temperature. Firstly, we analize the constraint structure and show that it is a second class constraint theory. Afterwards, we introduce the partition function by means of path integrais and study the Bose Einstein Condensation (BEC), we show that the theory has the zero mode, crucial for the existence of BEC. This analysis show identical results that were obtained by means of the KGF and Proca theories. The problem of equivalence is also studied for the case of non-zero temper- ature. We show, in general form, that the photon Green functions in the case of DKP e KGF theories are identical. We also calculate the vacuum polariza- tion in the one loop approximation and obtain the temperature dependent and independent contributions as they were obtained via the KGF theory / Doutor

Orientador: Sadhan Kumar Adhikari / Banca: Arnaldo Gammal / Banca: Dionisio Bazeia Filho / Banca: Roberto André Kraenkel / Banca: Valery Shchesnovich / Resumo: Nesta tese estudamos conceitos básicos de um condensado de Bose-Einstein (BEC) e sua extensão para sistemas com propriedades mais "exóticas", incluindo misturas de dois componentes, com algumas características interessantes encontradas devido à interação entre espécies, e condensados de átomos com forte momento (magnético) dipolar, nos quais a interação dipolo-dipolo (anisotrópica e de longo-alcance), abre novas possibilidades de pesquisa na procura por desconhecidas e fascinantes características para gases atômicos ultra-frios. Mostramos o modelo de campo-médio para misturas de dois BECs interagindo através do potencial de contato e da interação dipolar de longo-alcance empregando termos não lineares de inter e intra-espécies. Aplicamos este modelo em sistemas binários com diferentes armadilhas em que um deles ou ambos podem ser dipolares. Especificamente, estudamos as características físicas de uma mistura de dois BECs - com e sem interação dipolar -, a formação (e dinâmica) de bright solitons para um BEC dipolar, algumas propriedades interessantes para um BEC dipolar no limite de interação forte, e as características de um BEC dipolar quase-livre vinculado à um outro BEC não dipolar confinado numa armadilha magnética. Apresentamos nossos resultados numéricos usando gráficos de densidade, diagramas de fase, de formação de estruturas nas densidades ou a dinâmica dos sistemas, entre outros. Sempre que possível, nossos resultados serão associados com quantidades usadas em técnicas experimentais através de um tipo específico de átomo, o número de partículas, os valores dos parâmetros de interação, a anisotropia da armadilha ou outras quantidades relacionadas com observáveis experimentais / Abstract: We described the basic ideas of Bose-Einstein condensation (BEC), and then we focused our study on extensions to more exotic condensates including mixtures of two components, where interesting characteristics are found due to the interspecies interaction, and magnetic dipolar gases, which with their ansiotropic long-range dipolar interaction have opened up new avenues of research into cold atoms, in a quest for novel and fascinating features. In this thesis, we present the mean-field model for the binary BEC interacting two-componente mixtures of dipolar and nondipolar BECs, the formation and dynamics of bright solitons, the strong coupling domain for dipolar BECS, and the features of an untrapped bound dipolar droplet in a trapped nondipolar condensate. Our numerical results are presented in density plots, stability, phase plots, structure formartion in densities, breathing oscillation, and more. However, these solutions, whenever possible, are associated with quantities widely handled in experimental techniques, theough a specific types of atoms, number of particles, values of parameters of interaction or the anisotropy of trap, and others quantities related to experimental observables / Doutor

São investigadas, utilizando-se a distribuição grande canônica, as modificações introduzidas nas propriedades termodinâmicas e magnéticas de um sistema de bosons confinado por um potencial harmônico cilindricamente e esfericamente simétrico. O sistema apresenta condensação de B.E. somente no limite de confinamento fraco e a causa desta transição é devido a não homogeneidade do sistema, além da dependência da função densidade de estados próximos da energia mínima. Para este limite de confinamento fraco, são analisados ainda os limites de campo magnético forte ou fraco, apresentando comportamentos distintos, podendo ser comparados com o sistema de May ou com o sistema de gás ideal não confinado e com campo magnético nulo (sistema livre). A ordem da transição analisada constatando-se não ser de primeira ordem. O calor específico mostra uma descontinuidade finita na temperatura de transição. Abaixo desta temperatura de transição, o sistema apresenta uma magnetização espontânea, valendo então a lei B-H. / The modifications introduced in the thermodynamic and magnetic properties of a bosons system which is limited by a spherical and cylindrically harmonic potencial are investigated, using the grand canonical distribution. The system presents B.E. condensation only in the weak confinement limit and the cause of this transition is due to the non-homogeneity of the system in addition to the dependence of the density function of states near the minimum energy level. About this weak confinement limit, the limits o£ the strong or weak magnetic field are analysed too. The limit of the strong or weak magnetic field show distinctive behavior and they may be compared with the May\'s system or with the non-confined system of the ideal gas and with the null-magnetic field (free system). The order of this transition is analysed and it is verified as not being of the first order. The specific heat present a finite discontinuity in the transition temperature. Below this transition temperature, the system presents a spontaneous magnetization thus satisfying the B-H law.

M.Ing. / Heat transfer and pressure drop characteristics during in-tube condensation of nonazeotropic mixtures of R22/R142b in a smooth helically coiled copper tube with an inside diameter of 8.11 mm are investigated. The experimental results are compared with prediction from correlation. The coefficient of performance of.the heat pump built and used for experiments has been studied. The mass flux of the refrigerant was varied during the course of the experiments. At similar mass flow rate of fluids, the average heat transfer coefficients for mixtures were lower than those for pure refrigerant R22 used as reference for comparison. Also, the heat transfer coefficients of all the refrigerants increased with increasing mass flux.

Numerous factors play a role in the development and maintenance of North Atlantic tropical cyclones as they originate and cross the Main Development Region. These factors include sea-surface temperatures (SSTs), relative humidity, vertical wind shear, etc. One key player in many of these factors is the Saharan Air Layer (SAL) which has been a source for study for nearly five decades. The interplay between dust loading within the SAL and the development of African Easterly Waves (AEWs) has been repeatedly noted in many of the studies in this field. The cumulative indirect effect of the dust on AEWs however remains unknown (Evan et al., 2006a). On a case by case basis, the SAL has been shown to negatively influence the development of AEWs, i.e. entrainment of dry air into the low to mid-levels, enhanced vertical wind shear and suppression of convection within the storm (Dunion & Velden, 2004). Positive influences on AEW development have also been attributed to the SAL, namely its enhancement of the African Easterly Jet (AEJ) which in turn helps produce positive vorticity along its southern edge that AEWs tap into for energy (Karyampudi & Pierce, 2002). Further study is indeed warranted to try to fully understand whether or not the SAL has a positive or negative influence on the development of AEWs. A polarized view may be inadequate, as the SAL’s role could very well be positive, negative or somewhere in between depending on the storm characteristics and environmental conditions present at that unique time. This study looked into the role dust loading has on the mixing between the SAL and the moist marine boundary layer directly beneath the base of the SAL, which can range from 500 – 1500m and revealed a dynamic and varying relationship. It also demonstrated, through a decrease in cloud top temperatures, that dust levels are associated with the convective strength of AEWs by acting as cloud condensation nuclei (CCNs). However this association can be nullified through other parameters unique to each individual storm; SSTs, vertical wind shear, dry-air entrainment, etc.

The conceptual design and basic layout of a modular refrigerant test system capable of flow condensation and evaporation were performed. The purpose of this study was the investigation of flow patterns during refrigerant condensation in intermittent flow in order to improve the prediction models. An objective flow pattern descriptor was developed to identify and describe transitions in flow regimes. The methods developed and utilised in this study were used to develop a time-fractional map of the intermittent flow regime. The time-fractions are statistical averages of gravity dominated and shear dominated flows occurring in intermittent flow. / Dissertation (MEng (Mechanical Engineering))--University of Pretoria, 2008. / Mechanical and Aeronautical Engineering / MEng / Unrestricted

Chapter 1: An assessment of the mechanism of the benzoin condensation. The reaction under non-hydroxylic conditions. The generally accepted mechanism for the well known benzion condensation is unviable for the following reasons: 1) No experimental evidence for formation of carbanion from oxyanion. 2) No experimental reports on pKa of ‘C-H” in intermediate oxyanion. 3) From previous reports, these types of carbanion are stable only at -78° C. 4) Carbanions possessing nucleofuges generally form carbenes. It was observed that the O- protected benzaldehyde cyanohydrin (1) and O-MOM protected ethyl mandelate (2) are possibly less acidic than benzyl cyanide (3). Attempts to affect hydrogen-deuterium exchange in the O-methyl ether of benzaldehyde cyanohydrin (1) did not yield clear-cut results; neither could the analogous carbanion from O-MOM protected ethyl mandelate be formed, under analogous conditions. O-Protected benzaldehyde cyanohydrin and O-MOM protected ethyl mandelate (2) did not condense with electrophiles like benzaldehyde (4); however benzyl cyanide (3) was condensed with benzaldehyde to form the stilbene cyanide (5) under similar conditions to the benzoin condensation. Scheme 1: Reactions under benzoin conditions. All these evidences indicate that carbanions derived from 1 and 2 are not formed under the conditions of the benzoin reaction. An alternative mechanism via intramolecular participation in the cyanohydrin oxyanion leads initially to an imino-oxirane intermediate; electrophilic capture of this in the key step finally leads to benzoin (Scheme 2). This is an attractive possibility that avoids many of the problems of the earlier mechanism, and is also not incompatible with most of the available experimental evidence. Further experimental and theoretical work is indicated before an acceptable mechanism for the benzoin condensation finally emerges. Scheme 2: A possible alternative mechanism of benzoin condensation Scheme 2: A possible alternative mechanism of benzoin condensation From the studies on mechanism of benzoin condensation, it seems possible to form imino-oxirane from oxyanion of benzaldehyde cyanohydrin instead of carbanion by participation of cyanide ion. To prove the cyanide ion participation in mechanism of benzoin condensation and to avoid ambiguities from O-H peak, the reaction was performed in 1,4 dioxane solvent with benzaldehyde (4) and cyanide with the phase transfer catalyst 18-crown-6, instead of EtOH and H2O as solvent. After mixing the IR spectra for the crude product, indicated the formation of benzoin (8), which was confirmed upon work up. This led to the developing of a novel method for the benzion under anhydrous conditions. Scheme 3: Formation of benzoin under anhydrous conditions Chapter 2: Stereochemical stability of benzion. Generally α-hydroxy ketones undergo tautomerism to the enediol form, which are stabilized by intramolecular hydrogen bonding. Because of this, they undergo racemisation. Benzoin is also a α-hydroxy ketone, but it can be resolved into its enantiomeric forms. It indicates enediol form of benzion is unstable possibly due to steric interference. It was observed from the crystal structure of the carbonate analog of ene-diol form of benzoin that there is steric interference between the two phenyl rings. These were twisted out of the plane of the carbonate moiety by 19.92° and -47.32°. (The crystal structure of 4,5-diphenyl-1,3-dioxol-2-one (9) was reported first time.) This structure also indicated the existence of atropisomerism in the crystalline lattice. Chapter 3: Polymerisation of benzaldehyde. α-Hydroxy esters can be viewed as surrogates of cyanohydrins. To prove the cyanohydrin anion intermediate in classical benzoin condensation mechanism is very difficult. An interesting alternative is to employ α-hydroxy esters instead. It was observed that methyl 2-phenylglyoxylate and methyl 2-(methoxymethyl)-2-phenylglyoxylate (2) failed to react with benzaldehyde in aqueous methanol with sodium carbonate as base. IR spectra indicated that the carbonyl peak of benzaldehyde has disappeared, but NMR spectra showed a mixture of methyl 2-(methoxymethyl)-2-phenylglyoxylate (2) and benzaldehyde (4). This seems to indicate the polymerization of benzaldehyde (10) (Scheme 4). However, the product was not stable enough to be isolated and purified. Scheme 4: Reaction between benzaldehyde and MOM-protected methyl mandalate (For structural formula pl see the abstract file.)