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L'objectif de cette thèse est de contribuer à la simulation numérique des transferts de chaleur par conduction dans les parois, par rayonnement et par convection thermosolutale dans des cavités fermées ou dans des conduites. Dans la plupart des cas pratiques, les trois modes de transfert de chaleur sont fortement couplés lorsque le fluide en mouvement est un mélange de gaz. Le transfert de chaleur par convection naturelle associé à la condensation surfacique dans une cavité à deux dimensions, remplie d'air humide a été étudié numériquement. Les parois verticales, d'épaisseur finie, sont en contact avec une ambiance extérieure froide. La modélisation faiblement compressible permet à la fois de tenir compte de la diminution de la masse du mélange et de la pression thermodynamique. Egalement, une étude de la convection mixte associée à l'évaporation d'un film liquide ruisselant sur les deux parois d'un canal vertical a été menée. Les effets des forces d'Archimède thermique et solutale sur le développement de l'écoulement ont été montrés. Les résultats ont été obtenus en considérant que les propriétés du mélange sont constantes ou basées sur la règle d'un tiers. Deux mélanges binaires de gaz parfaits air-vapeur et air-hexane ont été considérés en vertu de diverses conditions aux limites / The purpose of this thesis is the contribution to the numerical simulation of heat transfer by conduction, radiation and thermosolutal convection in a closed cavity or in a vertical channel. In most practical cases, the three modes of heat transfer are strongly coupled when the fluid in motion is a mixture of gases. Heat transfer by natural convection and surface condensation in two-dimensional enclosures in contact with a cold external ambient through a wall of finite thickness was studied numerically. Special attention was given on the modeling of the flow of a binary mixture consisting of humid air. Low-Mach number assumption was introduced in order to account for decreases in mixture mass and average pressure within the enclosure between the initial and steady states. Also, a numerical investigation was conducted to study mixed convection in a vertical channel with evaporation of thin liquid films on wetted walls. The effects of the thermal and solutal buoyancy forces on the flow field, heat and mass transfer are illustrated. Results were obtained both for variable and for constant properties using the one-third rule. Air-water vapor and air-hexane vapor mixtures, assumed as ideal gases, are considered under various boundary conditions

The indirect effect of atmospheric aerosol on climate remains a large source of uncertainty in anthropogenic climate change prediction. An important fraction of this uncertainty arises from the impacts of organic aerosol on cloud droplet formation. Conventional thinking says that organic aerosol hygroscopicity, typically represented by the hygroscopicity parameter κ, increases with oxidation, most commonly represented by the oxygen to carbon ratio of the aerosol, O:C. Furthermore, these quantities are expected to increase as aerosol volatility decreases. Results indicate that the link between organic aerosol hygroscopicity and oxidation is not always straightforward, and in some cases, the average carbon oxidation state OSc appears to be a better indicator of oxidation than the oxygen to carbon ratio, O:C. In chamber and ambient studies, the least volatile fraction of the aerosol also appeared to be the least hygroscopic, contradictory to current thinking; however, in both cases, thermally-denuded aerosol showed greater oxidation, in terms of OSc, than non-denuded aerosol. When these findings are placed in the context of numerous published studies from a variety of different environment, the overall trend of increasing organic hygroscopicity with O:C still holds. This is also true for volatilized aerosol, though the magnitude of organic hygroscopicity is generally lower than that of non-denuded aerosol.

Computational Fluid Dynamics (CFD) has become one of the main instruments for the prediction of many commercial and research oriented fluid flow and heat transfer problems. While single phase flow analysis through CFD has gained grounds within the commercial industry, multiphase flow analysis is still the subject of further research and development. Heat Pipes and thermosyphones are no exception to this. However, the involvement of more than one fluid phase within these devices has made their analysis through CFD more challenging and computationally more demanding to perform. In this thesis, computational fluid dynamics is used as a modelling tool in order to predict the thermal hydraulic behaviour of multiphase environment within thermosyphones and heat pipes. Eulerian two-fluid method is used to solve the conservation equations for mass, momentum and energy, for each phase along with the inclusion of interfacial heat and mass transfer terms. Numerical predictions are obtained for the steady-state and transient operation of stationary thermosyphon, while rotating heat pipes operation is also simulated using axially and radially rotating heat pipe models. Apart from using the commercially available CFD code for the analysis of thermosyphones related simulation, numerical work is performed regarding the coupling of momentum equations based on Eulerian two-fluid modelling scheme. OPENFOAM open source code is used and modified to include the Partial Elimination Algorithm (PEA) for the coupling of interfacial exchange terms, including interfacial mass transfer term, in the momentum equations of both phases. Results obtained from above discussed studies provide good agreement with corresponding experimental and analytical observations.

Methods to generate, manipulate, and measure optical and atomic fields with global or local angular momentum have a wide range of applications in both fundamental physics research and technology development. In optics, the engineering of angular momentum states of light can aid studies of orbital angular momentum (OAM) exchange between light and matter. The engineering of optical angular momentum states can also be used to increase the bandwidth of optical communications or serve as a means to distribute quantum keys, for example. Similar capabilities in Bose-Einstein condensates are being investigated to improve our understanding of superfluid dynamics, superconductivity, and turbulence, the last of which is widely considered to be one of most ubiquitous yet poorly understood subjects in physics. The first part of this two-part dissertation presents an analysis of techniques for measuring and manipulating quantized vortices in BECs. The second part of this dissertation presents theoretical and numerical analyses of new methods to engineer the OAM spectra of optical beams. The superfluid dynamics of a BEC are often well described by a nonlinear Schrodinger equation. The nonlinearity arises from interatomic scattering and enables BECs to support quantized vortices, which have quantized circulation and are fundamental structural elements of quantum turbulence. With the experimental tools to dynamically manipulate and measure quantized vortices, BECs are proving to be a useful medium for testing the theoretical predictions of quantum turbulence. In this dissertation we analyze a method for making minimally destructive in situ observations of quantized vortices in a BEC. Secondly, we numerically study a mechanism to imprint vortex dipoles in a BEC. With these advancements, more robust experiments of vortex dynamics and quantum turbulence will be within reach. A more complete understanding of quantum turbulence will enable principles of microscopic fluid flow to be related to the statistical properties of turbulence in a superfluid. In the second part of this dissertation we explore frequency mixing, a subset of nonlinear optical processes in which one or more input optical beam(s) are converted into one or more output beams with different optical frequencies. The ability of parametric nonlinear processes such as second harmonic generation or parametric amplification to manipulate the OAM spectra of optical beams is an active area of research. In a theoretical and numerical investigation, two complimentary methods for sculpting the OAM spectra are developed. The first method employs second harmonic generation with two non-collinear input beams to develop a broad spectrum of OAM states in an optical field. The second method utilizes parametric amplification with collinear input beams to develop an OAM-dependent gain or attenuation, termed dichroism for OAM, to effectively narrow the OAM spectrum of an optical beam. The theoretical principles developed in this dissertation enhance our understanding of how nonlinear processes can be used to engineer the OAM spectra of optical beams and could serve as methods to increase the bandwidth of an optical signal by multiplexing over a range of OAM states.

The degree of DNA supercoiling in the cell is carefully controlled by DNA topoisomerases. These enzymes catalyze the passage of individual DNA strands (Type I DNA topoisomerases), or double helices (Type II DNA topoisomerases) through one another. The purpose of the present study is to conduct a detailed analysis of the topo llα and β mRNAs expressed in several vertebrate cell lines. The final aim of this project is to analyze the relative roles of topo llα in chromatin condensation and chromosome segregation during mitosis, by performing topo llα gene targeting experiments in the DT 40 chicken lymphoblastoid cell line. The knock-out strategy was based on the observation of a high rate of homologous recombination versus random integration in the DT40 cell line. The topo llα gene was shown to be located on the chicken chromosome 2 (APM unpublished), for which the DT40 cell line is trisomic. The targeting vector completely replaced the 32 kb topo IIα genomic locus, generating a topo llα (-/+/+)cell line, which showed an increased resistance to topo II inhibitors. Paradoxically, 150 uM etoposide or 100 uM mitoxanthrone induced apoptosis within 5 hours in the topo llα (-1+1+) cell line, more rapidly as compared to the normal DT 40 cells. A topo IIα (-I-I+) cell line has also been generated. This study revealed the presence of evolutionarily conserved alternatively spliced forms of both topo llα and β isoforms between birds and humans. Hybridization screening of two chicken cDNA libraries, MSB-1 and DU249, revealed the presence of two distinct forms of both topo llα and β cDNAs. One form of topo llα, designated topo llα-1, encodes the chicken topo llα amino acid sequence previously reported (dbjiAB007445) in the database (unpublished). The second form, designated topo llα-2, encodes a protein containing an additional 35 amino acids inserted after Lysine-322 of chicken topo IIα-1 protein sequence. In the case of topo 11(3 mANA, one form, designated topo IIβ-1, encodes the protein already described (dbjiAB007446). The second form, tapa IIβ-2, would encode a protein missing the next 86 amino acids after Valine-25 in tapa II β-1 protein sequence. The tapa 11β variant is positioned similarly to one previously described in human (Hela) cells. The 5 amino acid insertion in the human tapa 11β-2 variant follows v23. In chicken cells, a longer insertion of 86 amino acids sequence follows v25, the homologous position in the tapa 11β protein. In human cells, the situation with tapa llα is more complex, as revealed by RT-PCR experiments (APM, unpublished) which generated several bands. One of these amplified species was found to contain a 36 amino acids insertion, positioned after residue K321 in the human tapa IIα cDNA, similarly to chicken tapa IIα-2 variant. The second human tapa llα spliced form cDNA was shown to contain a 26 amino acids insertion after residue A401 in the canonical human tapa llα protein sequence. The third cDNA variant isolated from human cells was described to encode a 81 amino acids insertion after residue Q355 positioned within the known human tapa IIα protein. It appears possible that the posttranslational modifications of the a-2 and β-2 isoforms may differ substantially from those of the canonical a-1 and β-1 isoforms. Such variant proteins could fulfil specialized functions, which might be tissue or cell-type specific. In summary, two novel forms of tapa llα and β cDNAs have been identified in three chicken cell lines. These spliced versions of both tapa llα and 13 isoforms seem to be evolutionary conserved, with similar forms occurring in their human counterparts. Future functional analysis of vertebrate tapa IIα and β will have to account for the existence of these novel isoforms, which might encode proteins that may exhibit different regulation of their subcellular localization, interaction with other proteins, or catalytic activity.

A variety of organometallic-fused heterocycles and acene quinones were prepared and characterized. This work was divided into three parts: first, the synthesis of 5,5-fused heterocyclic complexes of tricarbonylmanganese and (1’,2’,3’,4’,5’-pentamethylcyclopentadienyl)ruthenium; second, the synthesis of 1,2-diacylcyclopentadienyl p-cymene complexes of ruthenium(II); and third, synthesis of cyclopentadienyl-fused polyacenequinone complexes of ruthenium, iron and manganese. The first examples of the convenient, versatile and symmetric cyclopentadienyl-fused heterocycle complexes of (1’,2’,3’,4’,5’-pentamethylcyclopentadienyl)ruthenium(II) and tricarbonylmanganese(I) were synthesized starting from (1,2-dicarbophenoxycyclopentadienyl)sodium. The sodium salt was transmetalated using [MnBr(CO)5] and 1/4 [Ru(μ3-Cl)(Cp*)]4 to give [Mn(CO)3{η5-C5H3(CO2Ph)2-1,2}] and [Ru{η5-C5H3(CO2Ph)2-1,2}(Cp*)]. The diester complexes were saponified under basic conditions to obtain the corresponding dicarboxylic acids. The dicarboxylic acids were used to synthesize unique cyclopentadienylmetal complexes including diacyl chlorides, anhydrides, thioanhydrides and p-tolyl imides of ruthenium and manganese. Similarly, a series of 1,2-diacylcyclopentadienyl-p-cymene cationic complexes of ruthenium were synthesized using thallium salt of 2-acyl-6-hydroxyfulvene and [Ru(η6-p-cymene)(μ-Cl)Cl]2 in a 2:1 ratio with an intension of converting them into heterocycle-fused cationic sandwich complexes. However, our attempts of ring closing on 1,4-diketons with sulfur or selenium were unsuccessful. A methodology involving the synthesis of metallocene-fused quinone complexes was employed starting from pentamethylruthenocene-1,2-dicarboxylic acids. The diacyl chloride was prepared in situ from the dicarboxylic acids and used for Friedel-Crafts acylation. We observed single-step room-temperature diacylation of aromatics, including benzene, o-xylene, toluene, 1,4-dimethoxybenzene and ferrocene with pentamethylruthenocene-1,2-diacyl chloride to obtain the corresponding quinone complexes. Similarly, we synthesized mononuclear and binuclear γ-quinones by aldol condensation of 1,2-diformylcyclopentadienylmetal complexes with cyclohexane-1,4-dione or 1,4-dihydroxyarenes. The third methodology involves the Friedel-Crafts acylation of ferrocene with 2-carbomethoxyaroyl chlorides followed by saponification, carbonyl reduction, and ring closing by second Friedel-Crafts acylation to give Ferrocene-capped anthrone-like tricyclic and tetracyclic ketones. The oxidation of the ketones gave [3,4-c]-fused α-quinone complexes of iron. The oxidative and reductive coupling, enolization and C-alkylation of the anthrone complex were studied. Solvolysis of α-carbinol gave α-ferrocenylcarbenium salt, which underwent dimerization on treatment with non-nucleophilic base. We were successful to trap the in situ generated trimethylsilylenol ether of ferrocene-anthrone using dienophiles like N-phenylmaleimide or dimethylacetylenedicarboxylate under Diels-Alder conditions.

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Approved for public release; distribution is unlimited / Heat-transfer measurements were made for condensation of R-113 and steam on a smooth tube and on three finned tubes with rectangular shape fins. These tubes had a fin height and width of 1.0 mm and spacings of 0.25, 1.5, and 4.0 mm (tubes A, B, and C respectively) . Data were taken by increasing the vapor velocity from 0.4 to 1.9 m/s for R-113 and 4.8 to 31.3 m/s for steam. For both fluids, the improvement of the condensing heat-transfer coefficient with vapor velocity was smaller for the finned tubes than for the smooth tube. For R-113, the smooth tube experienced a 32 percent improvement with vapor velocity, where the finned tubes (tubes A, B and C respectively) experienced improvements of only 0, 5 and 10 percent. For steam, the smooth tube experienced a 62 percent improvement, whereas the finned tubes (tubes A, B, and C respectively) experienced improvements of only 31, 11, and 9 percent. These test results show that, although finned tubes can provide significant heat transfer enhancement over smooth tubes at low vapor velocities, the degree of enhancement becomes smaller as vapor velocity increases. / CBT-8603582 (NSF) / http://archive.org/details/effectofvaporvel00hopk / National Science Foundation / Lieutenant Commander, United States Navy