Made available in DSpace on 2015-05-14T13:21:37Z (GMT). No. of bitstreams: 1 parte1.pdf: 2426440 bytes, checksum: ed3c18b465357e2c561cffbd380b983f (MD5) Previous issue date: 2008-07-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The chemiluminescence (CL) of luminol-cobalt(II) reaction has been used in analytical systems for capillary electrophoresis, chromatography, -TAS (microTotal Analysis System), etc. Even with the diversity of applications, the steps of this reaction have not been completely elucidated and have been still a subject of research and controversy. Many works reported only to the isolated studies of the influence of each variable in the luminol-cobalt(II) reaction and, as such studies do not consider the interactions among variables, they do not exploit the total performance of this reaction in order to increase the chemiluminescent intensity (ICL). In this context, the use of an experimental design and a ChemiLumimetric Flow-Batch System (CLFBS) is proposed in this work in order to study and to optimize this reaction, aiming at to develop an automatic method to determine vitamin B12 (VB12) in drugs. For optimization purpose, a 24 factorial design was carried out fixing the cobalt concentration at 3.0 g L-1 and varying the concentration of luminol, hydrogen peroxide, sodium hydroxide and the order of mixture of these reagents. Sixteen assays were performed in five replicates, generating a total of eighty experiments. The analysis using normal plot of the experimental design revealed that the luminol concentration and the order of mixture of the reagents are variables more important than the NaOH or H2O2 concentrations to luminol-cobalt(II) reaction. These two parameters were responsible to enhance the chemiluminescent signal in about 80%. Another study was carried out in order to evaluate the CLFBS performance by using the optimized variables which were suggested by the factorial design study. Calibration curves were built by using standard solution of Co(II) and VB12 and the analytical parameters for Co(II) curve were: ΔICL = -21.39 +1771.37[Co2+] (r2 = 0.9996), LD and LQ = 12.0 ng L-1, RSD = 1.8% (n = 5), analytical sensitivity = 1947.29 W/g L-1; and VB12 curve were: ΔICL = -186.71 + 12.90 [VB12] (r2 = 0.9999), LD = 14.53 mg L-1 and LQ = 14.70 mg L-1, RSD = 2.1% (n = 4) and analytical sensitivity = 10.76 W/μg L-1. The results of the vitamin B12 analysis in drug samples employing the luminol-cobalt(II) reaction and CLFBS were enough satisfactory. Relative errors smaller than 4% were obtained by using curve calibration or standard addition method. The recovery studies yield very good values, which were of 97 to 103%. In addition, a good agreement was obtained when a drug sample was analyzed by the proposed and the reference (HPLC) method. Thus, the automatic chemilumimetric method, which was here developed and optimized, can be considered a promising alternative to quality control of vitamin B12 in drugs. / A quimiluminescência (QL) da reação luminol-cobalto(II) vem sendo empregada em sistemas analíticos de eletroforese capilar, cromatografia, -TAS (microTotal Analysis System), etc. Mesmo com a diversidade de aplicações, essa reação possui etapas pouco elucidadas que continuam sendo alvo de pesquisas e polêmicas. Muitos trabalhos relatam apenas estudos isolados da influência de cada variável na reação luminol-cobalto(II) e, por não considerar as interações entre as variáveis, estes estudos não exploram ao máximo a performance analítica desta reação. Neste contexto, foi proposto neste trabalho o uso de um planejamento experimental e de um Sistema Quimilumimétrico Fluxo-Batelada (SQLFB) para o estudo e a otimização desta reação com vista a desenvolver um método automático para a determinação de vitamina B12 (VB12) em medicamentos. Na otimização, foi utilizado um planejamento fatorial 24 em que foi mantido constante a concentração de cobalto(II) em 3,0 g L-1 enquanto variou-se as concentrações de luminol, peróxido de hidrogênio, hidróxido de sódio e a ordem de mistura destes constituintes. Foram efetuados dezesseis ensaios em quintuplicata, perfazendo um total de 80 experimentos realizados. A análise usando o gráfico normal do planejamento experimental revelou que a concentração de luminol ([Lu]) e a ordem da mistura (OM) dos reagentes são variáveis mais importante do que a concentração de NaOH e H2O2 para a reação luminol-cobalto(II). Ambas variáveis [Lu] e OM foram responsáveis por aumentar o sinal quimiluminescente em cerca de 80%. Um outro estudo foi realizado para avaliar a performance do SQLFB, empregando as variáveis otimizadas que foram sugeridas pelo estudo do planejamento fatorial. Curvas de calibração foram construídas utilizando soluções padrão de Co(II) e de VB12 e os parâmetros analíticos para a curva Co(II) foram: ΔIQL=-21,39+1771,37[Co2+](r2 = 0,9996), LD=1,54 ng L-1 e LQ=5,13 ng L-1, DPR=1,8% (n=5) e sensibilidade analítica=1947,29 Watts/μg L-1; e para a curva VB12 foram: ΔIQL= -186,71 + 12,90[VB12] (r2 = 0,9999), LD=0,89 μg L-1 e LQ = 2,98 μg L-1, DPR=2,1% (n=4) e sensibilidade analítica=10,76 Watts/μg L-1. Os resultados obtidos nas análises de vitamina B12 em medicamentos empregando a reação luminol-cobalto(II) e o SQLFB foram bastante satisfatórios. Erros relativos menores do que 4% foram obtidos empregando as técnicas de curva de calibração e de adição de padrão. Em estudos de recuperação, os valores foram também muito bons, ficando entre 97 e 103%. Além disso, uma boa concordância entre os resultados foi obtida quando uma amostra foi analisada empregando o método aqui proposto e o método de referência (HPLC). Portanto, o método quimilumimétrico automático aqui desenvolvido e otimizado pode ser considerado uma alternativa promissora para o controle de qualidade de vitamina B12 em medicamentos.

Estudos envolvendo o oxigênio molecular singlete (1O2) tem uma relevância biológica, uma vez que esta espécie, devido ao caráter eletrofílico, reage com moléculas ricas em elétrons como proteínas, lipídeos e DNA provocando danos que resultam em perdas de função e integridade celular. Em sistemas biológicos, a presença de outras espécies reativas de oxigênio e nitrogênio, dificultam a identificação de lesões específicas causadas por 1O2 .Neste contexto, este trabalho foi desenvolvido objetivando a síntese de endoperóxidos isotopicamente marcados com 17O para serem utilizados como fonte geradora limpa de 17[1O2] em estudos mecanísticos. A capacidade de geração de 17[1O2] pelo endoperóxido N,N\'-di(2,3-dihidroxipropil)-3,3\'-(1,4 naftilideno) dipropanamida 17O (DHPN17O2) foi confirmada utilizando o captador químico sulfato mono-{2-[10-(2-sulfoxi-etil)-antracen-9-il]-etil}éster de sódio e o nucleosídeo 2\'- desoxiguanosina. Os produtos isotopicamente marcados com 17O formados foram analisados por espectrometria de ressonância magnética nuclear e cromatografia líquida de alta eficiência acoplado ao espectrômetro de massa. Os lipídeos, em especial o colesterol ao reagir com o 1O2 geram hidroperóxidos de colesterol como produtos de oxidação primária e na presença de metais resulta em compostos de maior reatividade e toxicidade, como os radicais peroxila, que contribuem para a propagação da peroxidação lipídica. Neste trabalho, demonstramos que os hidroperóxidos de colesterol são capazes de gerar 1O2 na presença de metal através de medidas de luminescência, utilização de supressores e captador químico de 1O2. Os mecanismos de reação envolvidos foram estudados e determinados por espectrometria de massa acoplada a cromatografia líquida de alta eficiência. Por fim, a caracterização detalhada dos produtos formados por espectrometria de ressonância magnética nuclear e massa na reação do colesterol com 1O2 mostrou que além dos hidroperóxidos a reação também produz um aldeído, o 3&#946; -hidroxi-5&#946;-hidroxi-B-norcolestano-6&#946;-carboxialdeído. Até o momento, este composto havia sido identificado como um produto específico da ozonização do colesterol. Neste estudo, baseado nos estudos por reações de quimiluminescência, é proposto o mecanismo de formação deste aldeído em reações de oxidação de colesterol por 1O2 envolvendo intermediário dioxetano. / Studies involving singlet molecular oxygen (1O2) has biological relevance, once this species, due to its eletrophylic character, reacts with rich electron molecules such as proteins, lipids and DNA causing damages that result in loss of function and cellular integrity. In biological system, the presence of other reactive species of oxygen and nitrogen impair the identification of lesions caused by 1O2. In this context, this work was developed with the aim of synthesizing <SUP17O-labeleded endoperoxides to be used as a clean source of (1O2) in mechanistic studies. The ability of 17[1O2]generation by N,N\'-di(2,4-dihydroxypropyl)-1,4-naphthalene-dipropanamide labeled with 17O(DHNP17O2) was observed using the disodium salt of anthracene-9,10-diyldiethyl disulfate as a chemical trap and the nucleoside 2\'-deoxyguanosine. The products isotopically labeled with 17O were analyzed by nuclear magnetic resonance spectroscopy and high performance liquid chromatography coupled to a mass spectrometer. Lipds, in special the cholesterol, when reacting with singlet molecular oxygen generate cholesterol hydroperoxides as primary products and in the presence of metals result in compounds of higher reactivity and toxicity, such as peroxyl radicals which contribute to the propagation of lipid peroxidation. In this work, we demonstrated that cholesterol hydroperoxides are able to generate singlet molecular oxygen in the presence of metal by chemiluminescence measurements by testing the effect of singlet molecular oxygen quencher and by chemical trap. The involved reaction mechanisms were studied and determined by mass spectrometry coupled to the high performance liquid chromatography. Finally, we detailed characterization of the products formed in the reaction of cholesterol with 1O2 by nuclear magnetic resonance and mass spectroscopy showed that besides cholesterol hydroperoxides, the reaction also produces an aldehyde, 3&#946;hydroxy-5&#946;-hydroxy-B-norcholestan-6&#946;-carboxyaldehyde which had been identified as a specific product of cholesterol ozonization. In this study, based on the studies of chemiluminescence reactions, the mechanism of formation of this aldehyde in reaction of oxidation of cholesterol by 1O2 involving a dioxetane intermediate has been proposed.

The cyclic peroxides: diphenoyl peroxide (1), spiro-adamantyl-1,2-dioxetanone (2) and 4-(3-tert-butyldimethylsilyloxyphenyl)-4-methoxyspiro[1.2-dioxetane-3.2\'-adamantane] (3) synthesized, purified and characterized, also their kinetic and chemiluminescence (CL) properties were determined. The influence of solvent polarity on the chemiexcitation parameters of the catalyzed decomposition of 1 and 2, as well as the induced decomposition of 3 were examined in several binary solvent mixtures with different polarity and polarizability parameters, but similar viscosities. For solvents with low polarity, singlet quantum yields for the intermolecular catalyzed decomposition of diphenoyl peroxide (1,) and 1,2-dioxetanone (2) increase in function of medium polarity, showing maximum values in mediums of intermediate polarity, and decreasing in highly polar mixtures. For the induced decomposition of 3, the quantum yield showed to increase with increasing solvent polarity, including high polar solvent systems. In the binary solvent systems studied, the polarizability parameter showed to be contrary to the polarity values, therefore, it might appear that an increase of polarizability leads to a decrease in the singlet quantum yields for catalyzed decomposition of diphenoyl peroxide (1) and the induced decomposition of 3, however an increase in the singlet quantum yields for 1,2-dioxetanone 2. The three CL systems were also studied in binary solvent mixtures with different viscosities but similar polarity and polarizability parameters and singlet quantum yields showed an increase with increasing medium viscosity. Data were analyzed by using the collisional and the free volume models. The highly efficient intramolecular system induced 1,2-dioxetane 3 decomposition showed to be much more sensible to viscosity effects than the inefficient intermolecular systems. This surprising fact indicates that, even showing a significant solvent-cage effect, the induced 1,2-dioxetane should occur by an intramolecular electron back transfer. Moreover, chemiluminescence parameters of these systems were studied in several pure solvents. The obtained singlet quantum yields were correlated with viscosity, polarizability and polarity parameters by using multiple linear regression analysis. / Os peróxidos cíclicos: peróxido de difenoila (1), spiro-adamantil-1,2-dioxetanona (2) e 4-(3-terc-butildimetilsililoxifenil)-4-metoxispiro[1,2-dioxetano-3.2\'-adamantano] (3) foram sintetizados, purificados e caracterizados e as suas propriedades cinéticas e de quimiluminescência (CL) determinadas. A influência da polaridade do solvente sobre os parâmetros de quimi-excitação da decomposição catalisada de 1 e 2, e a decomposição induzida de 3 foi examinada em diversas misturas binárias de solventes com parâmetros de polaridade e polarizabilidade diferente, mas viscosidades semelhantes. Para solventes com baixa polaridade, os rendimentos quânticos singlete para a decomposição catalisada intermolecular do peróxido de difenoila (1) e 1,2-dioxetanona (2) aumentam em função da polaridade do meio, mostrando valores máximos em meios com polaridade intermediária, e diminuim para misturas altamente polares. Para a decomposição induzida de 3, o rendimento quântico mostrou aumentar com o aumento da polaridade do solvente, inclusive para sistemas com alta polaridade. Nos sistemas binários de solventes estudados, os parâmetros de polarizabilidade mostraram-se contrários aos valores de polaridade, portanto, parece que um aumento da polarizability leva a uma diminuição nos rendimentos quânticos singlete para a decomposição catalisada do peróxido de difenoila (1) e a decomposição induzida de 3, no entanto, um aumento nos rendimentos quânticos singlete para a 1,2-dioxetanona 2. Os três sistemas de CL também foram estudados em misturas binárias de solventes com diferentes viscosidades, mas com parâmetros de polaridade e polarizabilidade semelhantes e os rendimentos quânticos singlete mostraram aumentar com o aumento da viscosidade do meio. Os dados foram analisados usando tanto o modelos colisional quando o modelo de volume livre. Surpreendentemente, o sistema altamente eficiente decomposição induzida intramolecular do 1,2-dioxetano 3 mostrou-se muito mais sensível aos efeitos da viscosidade do que os sistemas intermoleculares ineficientes, o que indica claramente que a decomposição induzida do 1,2-dioxetano deve ocorrer por um processo de retro-transferência de elétron intramolecular. Além disso, os parâmetros de quimiluminescência destes sistemas foram estudados em vários solventes puros. Os rendimentos quânticos singlete obtidos foram correlacionados com parâmetros de viscosidade, polarizabilidade e polaridade usando análise de regressão linear múltipla.

Organic nitrates, such as nitroglycerine (NTG), are widely used for their potent vasodilator capacity in the management of coronary artery disease and heart failure. Unfortunately, their beneficial effect is rapidly lost due to the development of nitrate tolerance, which is translated by an impaired vasorelaxation to NTG and an increased oxidative stress production. Although the mechanisms of the development of nitrate tolerance are still not fully elucidated, much interest has been focused in treating nitrate-receiving patients together with other drugs in order to overcome the development of nitrate tolerance. The Nitric Oxide generating enzyme, eNOS, and the superoxide anion generating enzyme, NAD(P)H oxidase, have been suggested to play a role in the development of nitrate tolerance. The aim of this study was to analyse the underlying mechanism by which ramipril, an ACE inhibitor and rosuvastatin, a new molecule of the statin class, are able to protect against the development of nitrate tolerance in the aortas isolated from rats, wild-type (wt) and eNOS-/- mice. <p>These results show that ramipril as well as rosuvastatin are able to protect against the development of nitrate tolerance in the wt and eNOS-/- mice aortas suggesting that eNOS is not necessary for their protective effect. The aortas from nitrate tolerant rats and mice showed a significant increase in the NAD(P)H oxidase activation compared to the aortas from the control and from the co-treated ramipril+NTG or rosuvastatin+NTG animals. In line with these findings were the results obtained by RT-PCR analysis: the mRNA expression of the different subunits of the NAD(P)H oxidase, such as gp91phox, p22phox, were significantly decreased after rosuvastatin or ramipril treatment in wt and eNOS-/- mice aortas. Apocynin, the NAD(P)H oxidase inhibitor was also able to inhibit the development of nitrate tolerance in the rat and mouse aortas. <p>In conclusion, these results suggest that rosuvastatin and ramipril are able to protect against the development of nitrate tolerance by counteracting the nitrate-induced oxidative stress. The mechanism of protection involves a direct interaction with the NAD(P)H oxidase pathway and seems to be completely independent of the eNOS pathway. <p> / Doctorat en sciences pharmaceutiques / info:eu-repo/semantics/nonPublished

<p>A small plasma generation system was first developed using a ring-pin electrode configuration with the goal of producing a plasma disk at the burner outlet. Two distinct plasma regimes were identified: diffused and filamentary. Diffuse discharges were generated at low frequencies while filamentary discharges were generated at moderate to high frequencies. The induced flow fields generated by both diffuse and filamentary plasma discharges were investigated using high-speed schlieren visualization and particle image velocimetry. The rise in gas temperature was measured using optical emission spectroscopy. Lastly, the electrical properties for both types of plasma discharges was measured. The measurements provided a set of pulse parameters for the investigation of the plasma-flame interaction on the atmospheric pressure burner. </p> An atmospheric pressure plasma-assisted burner with a ring-pin electrode geometry was designed and fabricated to investigate the effect of nanosecond repetitively pulsed discharges on methane-air flames. The burner can produce both Bunsen-type and swirl-stabilized flames (helical vane swirlers, swirl number of 0.62) with a modular design to allow for a removable block swirler component. Flame chemiluminescence and direct imaging of flame structure and dynamics was done to understand the burner’s operating limits. The burner can operate 6 – 13 kW flames, with flames stabilizing at approximately 2 inches above the burner exit. The effect of air flow rate on plasma formation was investigated and it was found that the high velocity of the incoming gas changes the plasma regime and electrical properties. Finally, the plasma discharge was applied on lifted, swirled flames and used for plasma-assisted ignition. For lifted swirled flames, we found that a minimum of 100 pulses is required to generate a filamentary discharge in the air stream. Higher number of pulses at high frequencies appeared to extinguish the primary flame. A minimum of 6000 was used for ignition. The plasma-assisted burner will allow for future studies to investigate the plasma flame coupling for various conditions using a wide variety of diagnostics. <br>

The thesis discusses the methods of determination of tumor markers and their clinical importance in medical diagnostics. The theoretical part describes clinically important tumor markers and also the chemiluminescent immunoassay methods used for their determination. The practical part of the thesis describes the introduction of new chemiluminescent methods for the determination of tumor markers in routine operation, evaluates its basic analytical parameters and compares it with the existing immunoturbidimetric method. The practical part also presents results of monitoring of cancer patients with various tumors, which is performed by evaluation of the values of tumor markers. Comparison of our method with other methods within the context of System of external quality control is also documented.

L’imagerie moléculaire optique joue maintenant un rôle essentiel dans le diagnostic pré-clinique et le développement de médicaments. En effet, c’est un outil précieux dans la détection et le suivi de cellules vivantes que ce soit en utilisant de simples agents de marquage ou des sondes plus développées, dites « intelligentes » et activées uniquement par une interaction spécifique avec le bio-analyte ciblé. Ce travail de thèse a consisté à développer des outils synthétiques innovants afin d’optimiser les paramètres physico-chimiques et les propriétés optiques des sondes luminescentes. Ceci dans le but de répondre à la problématique complexe de l’imagerie dans le contexte in vivo. Nous avons notamment travaillé sur des aspects de pro-fluorescence et de chémiluminescence. De nouveaux pro-fluorophores à phénol basés sur une architecture originale de type bis-coumarinique ont été développés. De plus, nous avons mis en place une méthode d’hydrosolubilisation généralisable aux fluorophores à phénol de type coumarine et xanthène. Nos recherches en chémiluminescence ont permis la synthèse de nouveaux chémiluminophores couplés à des fluorophores organiques afin d‘augmenter l’efficacité d’émission de chémiluminescence dans le rouge. Enfin, nos travaux ont permis de mettre en place les premières « cassettes » chémiluminescentes basées sur une architecture de type 1,2-dioxétane. / Optical molecular imaging is now playing a pivotal role both in pre-clinical diagnosis and drug development. Indeed, this is a valuable tool for the real time detection and monitoring of living cells either through the use of structurally simple labels or more recently by means of sophisticated fluorescent probes, called “smart” probes and only activatable upon specific interaction with the targeted bio-analyte. The aim of this PhD work was the design of new synthetic tools aimed at optimizing physico-chemical and optical properties of fluorescent probes intended for challenging in vivo imaging applications. We have focused on the pro-fluorescence and chemiluminescence approaches. New phenol-based pro-fluorophores have been developed by using an original bis-coumarinic scaffold. In the context of the chemistry of fluorophores, we have also investigated a general method for the water-solubilisation of phenol-based fluorophore belonging to the coumarin and xanthene families. Our research in chemiluminescence has led the synthesis of new chemiluminophores covalently linked to fluorescent organic dyes aimed at increasing the emission efficiency in the red region of such chemiluminophores. Thus, the first chemiluminescent “energy transfer cassettes” based on a 1,2-dioxetane scaffold have been obtained.

Utilisation of New Biomarkers for the Optimalization of Diagnostics and Therapy of Tumors of the Gastrointestinal Tract Introduction: Tumor markers are standard diagnostic tools. They are mainly used to monitor the course of the disease and to check the efficacy of the treatment. It is important to observe dynamics. Changing the level of the biomarker can prevent clinical manifestation and lead to early diagnosis of relapse, which in turn means improving the quality of life, including prolonging survival. Recently, we have encountered a number of diagnostic algorithms that suggest algorithms for estimating the risk of tumor presence or the risk of progression of cancer, using statistical methods. Objectives: The aim of this work is to verify new biomarkers for the diagnosis of gastric cancer and to develop an optimal algorithm for their use. Further, to evaluate the importance of cytokeratin markers - Tissue Polypeptide Antigen (TPA) and Tissue Polypeptide Specific Antigen (TPS) for the diagnosis of metastatic colorectal carcinoma in the liver. To carry out a pilot study of FGF23 levels in people with colorectal carcinoma and other gastrointestinal tumors. Methods and patients: Patient samples were analyzed using immunoradiometric, chemiluminescence and fluorescence assays. For each solved problem,...

One of the most relevant group of toxicologically significant compounds in beer are N-nitrosamines. In this thesis, the attention was paid especially on non-volatile nitroso compounds whose concentrations in beer, a chemical structure, and a biological effect has not been known yet. For the reason of the lack of knowledge regarding this compound group, the method for their sensitive detection by chemiluminescence detection after gas chromatographic separation was developed. This method permits a classification of detected nitroso compounds to different groups (N-nitroso, C-nitroso, and combination of C-nitroso and nitro) and distinguish them from interferences. The method is based on recording of a pyrolytic profile of each chromatographic peak, the profiles are then processed by discriminant analysis. The method has been developed for finding and structural identification purposes of these unknown compounds. Its application on an artificially nitrosated beer sample, together with gas chromatographic tandem mass spectrometric analysis, led to structural identification of several representatives of nitroso compounds. Sensory active compounds in this thesis are represented by carbonyl compounds and fatty acids. Carbonyl compounds - furfural and hydroxymethylfurfural - were used during the development...

[ES] El proceso de combustión en llamas de difusión de combustible atomizado es un fenómeno multifásico altamente complejo que a día de hoy no se comprende en su totalidad, ya que involucra varios eventos simultáneos, como atomización, vaporización y cinética química. A lo largo de los años, los investigadores han estudiado a fondo la combustión en llamas de combustibles líquidos, con el fin de comprender los procesos fundamentales como clave para reducir las emisiones contaminantes y mejorar la eficiencia de la propulsión de las aeronaves. En los últimos años, la evolución tanto en la tecnología de inyección como en la de combustión ha permitido mejorar el proceso de mezcla por aspersión y la eficiencia del motor y, por tanto, reducir las emisiones contaminantes. Por lo que, diferentes configuraciones de tipo de inyector y distribución de aire dentro de la cámara de combustión han demostrado ser capaces de reducir el consumo de combustible, así como las emisiones de óxidos de nitrógeno y hollín sin afectar el rendimiento del motor. Esta tesis proporciona una metodología experimental para estudiar los efectos de las condiciones de co-flujo, el caudal másico de combustible, el tipo de combustible y el diámetro de salida del quemador sobre la atomización y la combustión de la llama producida en un quemador anular bajo condiciones de operación pobres. La caracterización del chorro sin combustión se realizó mediante dos técnicas ópticas diferentes. Por un lado, se utilizó velocimetría de imagen de partículas para medir los campos de velocidad del espray. Por otro lado, retroiluminación microscópica difusa (MDBI) para medir el tamaño y la velocidad de las gotas. Los resultados mostraron que ambos están controladas principalmente por el tipo de combustible y el caudal másico del mismo. Sin embargo, la variación de la velocidad de co-flujo no mostró un efecto significativo en las características de las gotas (tamaño y velocidad), lo que probablemente se deba a que el campo de visión de la técnica MBDI estaba muy cerca de la punta del inyector. Adicionalmente, al incrementar la temperatura de co-flujo se observó que el diámetro promedio de gota disminuía, lo cual es causado por la evaporación del combustible. Finalmente, las variaciones en los perfiles de tamaño y velocidad de las gotas al variar el diámetro de salida de aire se relacionaron con la variación de la velocidad del co-flow, lo que afectaba la evaporación y el arrastre de las gotas. Para el estudio de la llama en condiciones reactivas, se probó en condiciones de operación que permitan llama estabilizadas, utilizando tres técnicas ópticas diferentes, las cuales se activaron simultáneamente. La extinción de luz difusa se utilizó para determinar el espesor óptico del hollín. Además, se emplearon las técnicas de quimioluminiscencia OH* y MDBI para medir la altura de despegue de la llama y las características de las gotas, respectivamente. Los resultados mostraron que la velocidad y temperatura del co-flujo, y el tipo de combustible influyen fuertemente en la altura de despegue de la llama. Mientras que en la formación hollín los parámetros más influyentes fueron la velocidad del co-flujo y el tipo de combustible. Con respecto a los resultados de la evaporación de las gotas, se observó que el tamaño inicial y las propiedades del combustible controlan su evaporación. El combustible n-Dodecano es el menos volátil y tiene un tamaño de gota inicial más grande y, por lo tanto, las gotas tardaron más en evaporarse, lo que resultó en una mayor longitud de despegue de la llama y una mayor formación de hollín debido a su mayor tendencia a formar hollín. Por el contrario, las gotas de n-Heptano se evaporaron más rápido, lo que resultó en una altura de despegue de la llama más corta y también en una menor formación de hollín. Finalmente, el combustible n-Decano mostró resultados intermedios para la evaporación de gotas, la altura de despegue de la llama y la formación de hollín. / [CA] El procés de combustió en flames de difusió de combustible atomitzat és un fenomen multifásico altament complex que a hores d'ara no es comprén en la seua totalitat, ja que involucra diversos esdeveniments simultanis, com a atomització, vaporització i cinètica química. Al llarg dels anys, els investi- gadors han estudiat a fons la combustió en flames de combustibles líquids, a fi de comprendre els processos fonamentals com a clau per a reduir les emissions contaminants i millorar l'eficiència de la propulsió de les aeronaus. En els últims anys, l'evolució tant en la tecnologia d'injecció com en la de combustió ha permés millorar el procés de mescla per aspersió i l'eficiència del motor i, per tant, reduir les emissions contaminants. Pel que, diferents configuracions de tipus d'injector i distribució d'aire dins de la cambra de combustió, han demostrat ser capaços de reduir el consum de combustible, així com les emissions d'òxids de nitrogen i sutja sense afectar el rendiment del motor. Aquesta tesi proporciona una metodologia experimental per a estudiar els efectes de les condicions de co-flux, el cabal màssic de combustible, el tipus de combustible i el diàmetre d'eixida del cremador sobre l'atomització i la combustió de la flama produïda en un cremador anul·lar sota condicions d'operació pobres. La caracterització del doll sense combustió es va realitzar mitjançant dues tècniques òptiques diferents. D'una banda, es va utilitzar velocimetría d'imatge de partícules per a mesurar els camps de velocitat de l'esprai. D'altra banda, retroil·luminació microscòpica difusa (MDBI) per a mesurar la grandària i la velocitat de les gotes. Els resultats van mostrar que tots dos estan controlades principalment per la mena de combustible i el cabal màssic d'aquest. No obstant això, la variació de la velocitat de co-flux no va mostrar un efecte significatiu en les característiques de les gotes (grandària i velocitat), la qual cosa probablement es deu al fet que el camp de visió de la tècnica MBDI estava molt prop de la punta de l'injector. Addicionalment, en incrementar la temperatura de co-flux es va observar que el diàmetre mitjà de gota disminuïa, la qual cosa és causat per l'evaporació del combustible. Finalment, les variacions en els perfils de grandària i velocitat de les gotes en variar el diàmetre d'eixida d'aire es van relacionar amb la variació de la velocitat del co-flux, la qual cosa afectava l'evaporació i l'arrossegament de les gotes. Per a l'estudi de la flama en condicions reactives, es va provar en condicions d'operació que permeten flama estabilitzades, utilitzant tres tècniques òptiques diferents, les quals es van activar simultàniament. L'extinció de llum difusa es va utilitzar per a determinar la grossària òptica del sutge. A més, es van emprar les tècniques de quimioluminescència OH* i MDBI per a mesurar l'altura d'enlairament de la flama i les característiques de les gotes, respectivament. Els resultats van mostrar que la velocitat i temperatura del co-flux, i el tipus de combustible influeixen fortament en l'altura d'enlairament de la flama. Mentre que en la formació sutge els paràmetres més influents van ser la velocitat del co-flux i el tipus de combustible. Respecte als resultats de l'evaporació de les gotes, es va observar que la grandària inicial i les propietats del combustible controlen la seua evaporació. El combustible n-Dodecano és el menys volàtil i té una grandària de gota inicial més gran i, per tant, les gotes van tardar més a evaporar-se, la qual cosa va resultar en una major longitud d'enlairament de la flama i una major formació de sutge degut a la seua major tendència a formar sutge. Al contrari, les gotes de n-Heptano es van evaporar més ràpid, la qual cosa va resultar en una altura d'envol de la flama més curta i també en una menor formació de sutja. Finalment, el combustible n-Decano va mostrar resultats intermedis per a l’evaporació de gotes, l’altura d’envol de la flama i la formació de sutja / [EN] The combustion process in spray flames is a highly complex multi-phase phenomenon that is still not completely understood since it involves several simultaneous events, such as atomization, vaporization, and chemical kinetics. Over the years, researchers have studied the combustion in spray flames thoroughly, in order to understand the fundamental processes as key to re- duce pollutant emissions and improve the efficiency of aircraft propulsion. In recent years, the evolution in both injection and combustion technology has allowed to improve the spray mixing process and engine efficiency and hence, reducing pollutant emissions. Therefore, different configurations of injector type and air distribution inside the combustion chamber have proved capable of reducing fuel consumption, as well as emissions of nitrogen oxides and soot without affecting the engine performance. This thesis provides an experimental methodology to study the effects of co-flow conditions, fuel mass flow rate, fuel type and air outlet diameter at the burner exit on the atomization and combustion behavior of the spray flame produced on an annular spray burner under lean conditions. The characterization of the liquid spray without combustion was carried out using two different optical techniques. On the one hand, particle image velocimetry was used to characterize the global velocity fields of the spray. On the other hand, Microscopic diffused back-illumination (MDBI) to measure the size and droplet velocity at a field of view close to the injector tip. The results exhibited that both droplet size and droplet velocity are mainly controlled by the fuel type and fuel mass flow rate. Nevertheless, the variation of the co-flow velocity did not show a significant effect on droplet characteristics (size and velocity), which is likely due to the fact that the field of view of the MDBI technique was located very close to the injector tip. Additionally, by increasing the co-flow temperature, it was observed that the mean droplet size decreased, which is caused by the fuel evaporation process. Finally, the variations in the droplet size and velocity profiles when varying the air outlet diameter were related to the velocity variation when modifying the cross-sectional area at the burner outlet, which affects the evaporation and drag of the drops. On the spray development in reactive conditions, it was investigated in the operating conditions that promote stabilized flames, using three different optical techniques, all of which were triggered simultaneously. The light extinction was used to determine the optical thickness through the soot cloud. In addition, OH* chemiluminescence and the MDBI techniques were employed to measure the flame lift-off height and droplet characteristics, respectively. The results exhibited that the co-flow velocity, co-flow temperature and fuel type strongly influence the flame lift-off height. While in the soot formation the most influential parameters were the co-flow velocity and the type of fuel. Regarding the results of the droplet evaporation, it was observed that the initial droplet sizes and the fuel properties control the droplet evaporation process. n-Dodecane fuel is the least volatile and also exhibited a larger initial droplet size and thus, the droplets took more time to evaporate than the other two fuels, resulting in a longer flame lift-off height and likewise higher soot formation by its greater tendency to form soot. Contrary, n-Heptane droplets evaporated faster, resulting in a shorter flame lift-off height and also less soot formation. Finally, n-Decane showed intermediate results for droplet evaporation, flame lift-off height, and soot formation. / Cardona Vargas, S. (2021). Development of a test rig for the study of the atomization and combustion of a spray flame in an atmospheric annular spray burner at lean conditions [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/179994 / TESIS