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Made available in DSpace on 2014-12-17T15:01:27Z (GMT). No. of bitstreams: 1 SidrakJP_DISSERT.pdf: 3365381 bytes, checksum: 55b6f324d82bc4f385aa87921831ed44 (MD5) Previous issue date: 2011-12-20 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This dissertation aims to assess the representativeness of the manual chilled mirror analyzer (model II Chanscope 13-1200-CN-2) used for the determination of condensed hydrocarbons of natural gas compared to the indirect methods, based on thermodynamic models equation of state. Additionally, it has been implemented in this study a model for calculating the dew point of natural gas. The proposed model is a modification of the equation of state of Peng-Robinson admits that the groups contribution as a strategy to calculate the binary interaction parameters kij (T) temperature dependence. Experimental data of the work of Brown et al. (2007) were used to compare the responses of the dew point of natural gas with thermodynamic models contained in the UniSim process simulator and the methodology implemented in this study. Then two natural gas compositions were studied, the first being a standard gas mixture gravimetrically synthesized and, second, a mixture of processed natural gas. These experimental data were also compared with the results presented by UniSim process simulator and the thermodynamic model implemented. However, data from the manual analysis results indicated significant differences in temperature, these differences were attributed to the formation of dew point of water, as we observed the appearance of moisture on the mirror surface cooling equipment / O presente trabalho de disserta??o tem por objetivo avaliar a representatividade do analisador manual de espelho refrigerado (Chanscope II modelo 13-1200-C-N-2) usado para a determina??o do condensado de hidrocarbonetos de g?s natural frente aos m?todos indiretos, fundamentados em modelos termodin?micos de equa??o de estado. Adicionalmente, tem sido implementado neste estudo um modelo para c?lculo do ponto de orvalho de g?s natural. O modelo proposto constitui uma modifica??o na equa??o de estado de Peng-Robinson que admite a contribui??o de grupos como estrat?gia para calcular os par?metros de intera??o bin?ria kij(T) com depend?ncia da temperatura. Dados experimentais do trabalho de Brown et al. (2007) foram utilizados para comparar as respostas de ponto de orvalho do g?s natural com os modelos termodin?micos contidos no simulador de processo UniSim e com a metodologia implementada neste estudo. Em seguida, duas composi??es de g?s natural foram estudadas, sendo a primeira uma mistura padr?o de g?s sintetizada gravimetricamente e, a segunda, uma mistura de g?s natural processado. Tais dados experimentais foram tamb?m comparados com os resultados apresentados pelo simulador de processo UniSim e pelo modelo termodin?mico implementado. No entanto, os dados do analisador manual indicaram diferen?as significativas nos resultados de temperaturas, sendo estas diferen?as atribu?das ? forma??o de ponto de orvalho de ?gua, j? que foi observado o aparecimento de umidade sobre a superf?cie do espelho refrigerado do equipamento

Tato práce je zaměřena na systém vodního vstřikování a způsoby zajištění dostatečného množství potřebné kapaliny pro správný chod tohoto systému. Jedním zajímavým a nezávislým řešením je využití odpadních produktů motoru, a to vodní páry produkované spalováním paliva. Pro zajištění kondenzace je nutné zchlazení výfukových plynů pod rosný bod páry, což lze zajistit opatřením výfukového potrubí chladiči. Vzniklý kondenzát je pak potřeba efektivně oddělit od proudu plynů a zachytit. Návrh takovéhoto systému vychází z reálně naměřených dat a jeho následným ověřením pomocí CFD simulace.

To meet the continuously rising demand for natural resources and high-value compounds, the development of new and more efficient separation technologies is important from both an economic and environmental point of view. Moreover, the detailed knowledge of adsorption phenomena can be beneficial for the development of task-specific adsorbents for gas separation processes. However, new or supplementary measurement techniques are needed to broaden the understanding of the underlying molecular mechanisms and to characterize promising materials with a fast and reliable method. Raman spectroscopy holds the potential to advance the state-of-the-art in thermophysical property research for CCS technologies in multiple ways. It can not only be utilized for fundamental research on adsorption on quasi non-porous materials due to the possibility to monitor the composition of fluid mixtures but also for the characterization of newly developed porous adsorbents. In this context, Raman spectroscopy was explored in this work to characterize the sorption capacity of translucent porous materials and to investigate the underlying mechanisms that govern sorption processes.:1 Introduction 2 Motivation 3 Experimental Background 4 Adsorption on Quasi Non-Porous Materials 5 Adsorption on Translucent Porous Materials 6 Gas Solubility in Liquids 7 Conclusion and Outlook 8 References Appendix: A Determined Peak Intensities for Adsorption Measurements B Determined Peak Intensities for Solubility Measurements C Results for Absorption Measurements D Results for Solubility Measurements E Propagation of Error / Um den ständig steigenden Bedarf an natürlichen Ressourcen und hochwertigen Verbindungen zu decken, ist die Entwicklung neuer und effizienterer Trenntechnologien sowohl aus wirtschaftlicher als auch aus ökologischer Sicht wichtig. Darüber hinaus kann die detaillierte Kenntnis von Adsorptionsphänomenen für die Entwicklung aufgabenspezifischer Adsorbentien für Gastrennverfahren von Nutzen sein. Es werden jedoch neue oder ergänzende Messverfahren benötigt, um das Verständnis der zugrunde liegenden molekularen Mechanismen zu erweitern und vielversprechende Materialien mit einer schnellen und zuverlässigen Methode zu charakterisieren. Die Raman Spektroskopie hat das Potenzial, den aktuellen Stand der Technik bei der Erforschung thermophysikalischer Eigenschaften für CCS-Technologien in mehrfacher Hinsicht zu verbessern. Sie kann nicht nur für die Grundlagenforschung zur Adsorption an quasi nicht-porösen Materialien genutzt werden, da mit ihr Zusammensetzung von Fluidgemischen bestimmt werden kann, sondern auch für die Charakterisierung neu entwickelter poröser Adsorptionsmittel. In diesem Kontext wurde die Raman-Spektroskopie in dieser Arbeit eingesetzt, um die Sorptionskapazität von transluzenten porösen Materialien zu charakterisieren und die zugrundeliegenden Mechanismen zu untersuchen, welche die Sorptionsprozesse steuern.:1 Introduction 2 Motivation 3 Experimental Background 4 Adsorption on Quasi Non-Porous Materials 5 Adsorption on Translucent Porous Materials 6 Gas Solubility in Liquids 7 Conclusion and Outlook 8 References Appendix: A Determined Peak Intensities for Adsorption Measurements B Determined Peak Intensities for Solubility Measurements C Results for Absorption Measurements D Results for Solubility Measurements E Propagation of Error

Contexte : La dengue est une fièvre ayant pris davantage d’ampleur dans plusieurs régions du monde à climat tropical, dont le département Méta en Colombie, un lieu endémique dans la dernière décennie. Sachant que la propagation de cette maladie est entièrement dépendante des sites de reproduction du vecteur de transmission Aedes, l’investigation de prédicteurs environnementaux les affectant nous semblait pertinente d’un point de vue épidémiologique. Notre étude vise des retombées sur un plan de surveillance de santé publique et l’élaboration de programmes basés sur des observations temporelles et spatiales. Objectifs : Décrire la distribution spatio-temporelle de la dengue dans les 29 municipalités de Méta selon des prédicteurs environnementaux, soit les précipitations, la température ambiante, la température du point de rosée et la pression au niveau de la mer dans le cadre d’une étude écologique. Méthodes : Des données de surveillance SIVIGILA, de télédétection ainsi que de recensement DANE des 29 municipalités du département de Méta entre 2011 et 2019 ont été utilisées pour étudier l’association entre la dengue et les prédicteurs environnementaux. La modélisation de ces associations a été effectuée à l’aide d’un modèle de Markov cachés à changement de régime. Résultats : Des associations positives importantes ont été détectées entre les précipitations et l’incidence de la dengue atteignant des risques relatifs élevés (RR=1.97 à El Calvario à un décalage de 5 semaines ; RR=1.61 à San Juanito à un décalage de 20 semaines). La température ambiante et la température du point de rosée ont suivi en matière de pertinence n’excédant pas des RR de 1.11 pour la maladie. Or, la pression au niveau de la mer n’a pas présenté des résultats concluants. Selon les différents aspects étudiés dans les nombreuses cartes de ce mémoire, nous avons observé une dépendance géographique répétée à l’ouest du département. Conclusion : Nos conclusions recommandent qu’une attention particulière de la santé publique doit s’imposer quant à la prévention de la dengue en saison pluvieuse dans le Meta. Les hausses des valeurs de température ambiante et de la température du point de rosée peuvent expliquer certaines augmentations de l’incidence et incitent donc à la surveillance de ces paramètres également. À noter que nos résultats ont possiblement pu être influencés par un biais d’information et un biais de confusion. / Context: Dengue is a type of fever that has significantly spread in several regions of the world characterized by a tropical climate, including the Meta department in Colombia, which seemed to be an endemic place in the last decade. Knowing that the spread of this disease is entirely dependent on the reproduction sites of the Aedes transmission vector, the study of environmental predictors affecting those sites seemed relevant from an epidemiological point of view. Our study aims to add to the knowledge that can be used for public health surveillance and program elaboration based on temporal and spatial observations of dengue patterns within the region. Objectives: To describe the spatiotemporal distribution of dengue fever in the 29 municipalities of Meta according to its environmental predictors (i.e. precipitation, ambient temperature, dew point temperature and pressure at sea level) within the framework of an ecological study. Methods: SIVIGILA surveillance, remote sensing and DANE census data from 29 municipalities in the Meta department between 2011 and 2019 were used to study the association between dengue fever and environmental predictors. These associations were modeled using a regime-switching hidden Markov model. Results: Significant positive associations were detected between rainfall and dengue incidence reaching high relative risks (RR=1.97 in El Calvario at a 5-week lag; RR=1.61 in San Juanito at a 20-week lag). Ambient temperature and dew point temperature followed in terms of relevance not exceeding RRs of 1.11 for disease. However, pressure at sea level did not show conclusive results. According to the different aspects studied in the many geographical maps of this thesis, we observed a repeated geographical dependence in the west of the department. Conclusion: We recommend that special public health attention should be given to the prevention of dengue fever in the rainy season in Meta. Increases in ambient temperature values and dew point temperature may explain some increases in incidence and therefore prompt monitoring of these parameters as well. It should be noted that our results may have been influenced by an information bias and confusion bias.

NOx sensors have become salient components in the development of efficient exhaust after treatment system for heavy duty vehicles in the past few years. When the accumulated water inside the silencer splashes on to the NOx sensor, it can cause permanent cracks in the sensor. To protect the sensor from this mode of failure, a dew point strategy is developed at Scania. This is important to predict when it is safe to switch on the NOx sensor without causing any harm to it. But the strategy currently includes only the phase transfer phenomena and neglects the effect of the water blow out phenomena inside the silencer. To investigate the effect of water blow out, an experimental test method is designed and the experiments are conducted at different locations in the silencer. The results from the experiments shows that the effect of water blow out is certainly an important factor to develop a better dew point strategy model. For a selected location, the quantity of water remaining after blow out and the time taken for the blow out phase are collected as data from the experiments. A mathematical model for the water blow out phenomena is developed in MATLAB. The model estimates the maximum amount of water which could be present in all the subvolumes of the silencer considering the effect of water blow out. The model is verified with the experimental data for a Scania CAS1 silencer. Calibration guidelines for the developed blow out model are also documented in this report. / NOx sensorer har blivit viktiga komponenter i utvecklingen av ett effektivt avgassystem för tunga fordon under de senaste åren. När det ackumulerade vattnet i ljuddämparen stänker på NOx-sensorn kan det orsaka permanenta sprickor i sensorn. För att skydda sensorn från detta misslyckande utvecklas en daggpunktsstrategi på Scania. Detta är viktigt att förutsäga när det är säkert att slå på NOx-sensorn utan att skada den. Men strategin innehåller för närvarande endast fasöverföringsfenomenen och försummar effekten av att vatten blåser ut fenomen inuti ljuddämparen. För att undersöka effekten av utblåsning av vatten utformas en experimentell testmetod och experimenten utförs på olika platser i ljuddämparen. Resultaten från experimenten visar att effekten av vattenblåsning verkligen är en viktig faktor för att utveckla en bättre daggpunktsstrategimodell. För en vald plats samlas mängden vatten kvar efter utblåsning och den tid det tar för utblåsningsfasen som data från experimenten. En matematisk modell för fenomen för vattenblåsning utvecklas i MATLAB. Modellen uppskattar den maximala mängden vatten som kan finnas i ljuddämparens undervolymer med tanke på effekten av vatten som blåser ut. Modellen verifieras med experimentdata för en Scania CAS1 ljuddämpare. Kalibreringsriktlinjer för den utvecklade utblåsningsmodellen dokumenteras också i denna rapport.

This diploma thesis solves the problems of hydrothermal processes in walls of wooden houses and associated issues. A chosen were two apartment buildings, where they underwent exmerimental measurement of indor air, in order to determine the boundary conditions commonly boundary building evelope. Was followed by hygrothermal analysis of four commonly used constructions of wooden buildings in the Czech Republic, using various numerical methods. The quantity of information obtained from various numerical methods were analyzed individually. The final part of the thesis is devoted to experimental measurements of diffusion properties of materials. Namely foil vapor barrier, in terms of its influence on the perforation vapor diffusion resistance factor. Information obtained from the experiments were applied to re numerical analysis for walls with a foil vapor barrier. Followed by comparing both cases, in terms of changes hygrothermal behavior of structures with influence of perforation of the vapor barrier.

La pollution atmosphérique en milieu urbain est un problème préoccupant car une fraction croissante de la population mondiale vit dans les villes. Les effets de la pollution se manifestent également sur la végétation urbaine et sur notre patrimoine architectural, de sorte que c'est la qualité de la vie de l'ensemble des habitants des métropoles de la planète qui est en jeu. Il est indispensable de connaître la composition des atmosphères urbaines et de comprendre les mécanismes qui régissent cette composition pour évaluer les conséquences de la pollution, définir les exigences de réduction des émissions et établir des scénarios des tendances futures.<p><p>L'objectif du présent travail est de déterminer la composition chimique, les propriétés et le comportement des particules et des dépôts humides en Région bruxelloise. On a distingué les aérosols atmosphériques, les brouillards, les rosées (ou givres) récoltés à la fois sur les végétaux et sur un collecteur inerte, les pluies et les dépôts totaux (formés des pluies et des dépôts secs accumulés dans l'entonnoir de collecte en l'absence de pluie). Ce vaste objectif a été réalisé grâce à la collecte de nombreux échantillons sur une échelle de temps suffisante en différents endroits de la capitale, et à l'analyse de ces échantillons par des techniques variées et complémentaires (techniques classiques d'analyse d'échantillons liquides telles que spectrométrie d'absorption et d'émission atomique, chromatographie liquide, colorimétrie, ainsi que microscopie électronique et fluorescence des rayons-X). Trois collecteurs (pour le brouillard, la pluie et la rosée) ont été entièrement conçus et réalisés au laboratoire dans le cadre de ce travail. Les éléments suivants sont analysés: NO3, SO4, NH4, Na, Mg, Al, Si, P, S, CI, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Cd, Pb.<p><p>Afin de comprendre les causes de la variabilité spatio-temporelle des concentrations, l'influence de paramètres tels que la saison, la direction du vent, et le lieu de prélèvement a été examinée. De plus, dans le cas des pluies et des brouillards, l'étude de l'évolution des concentrations au cours d'un même épisode a permis d'investiguer les processus physico-chimiques qui contrôlent le dépôt humide. Elle a permis d'acquérir une meilleure connaissance des mécanismes d'incorporation des aérosols dans la phase aqueuse et du phénomène de lessivage de l'atmosphère. Tout au long de ce travail, les interactions entre la phase particulaire (aérosols) et les phases liquides (brouillards, rosées, pluies) ont été examinées. Une relation entre les concentrations en éléments dissous et le volume d'eau de l'échantillon a été établie dans le cas des pluies, des rosées et des brouillards. Cette relation traduit un effet de dilution et démontre l'importance du mécanisme de condensation-évaporation des gouttes d'eau. L'importance du phénomène de nucléation des sulfates, nitrates et chlorures d'ammonium constitutifs de la fraction fine de l'aérosol soluble a été démontrée. Ces sels d'ammonium sont formés secondairement par des réactions de conversion gaz-particules. L'abondance des ions ammonium, et l'importance de leur action de neutralisation de l'acidité, constituent une particularité de l'atmosphère bruxelloise.<p>L'identification des sources de particules et d'éléments en relation avec leurs propriétés chimiques et granulométriques a été réalisée en utilisant divers outils statistiques (corrélations entre éléments, analyse factorielle) et géochimiques (rapports de concentration, facteurs d'enrichissement, granulométrie). Les apports d'origine marine, continentale, biologique et anthropique (trafic, incinération des déchets, processus de combustion) ont ainsi été clairement mis en évidence dans l'aérosol et le brouillard bruxellois.<p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

The wettability and phase change phenomena of water are ubiquitous on biological and artificial surfaces. Properties like water repellency, self-cleaning, coalescence induced condensation jumping, anti-frosting, and dew harvesting arise on surfaces with particular structures and chemistry and are of particular interest for energy and water saving. This thesis collects different studies of wettability and phase change on natural and artificial surfaces: growth and self-ejection of condensation droplets on micro and nanostructured surfaces we fabricated, their applications, the Sliding on Frost of condensation droplets observed on the Cotinus Coggygria leaf, the dew harvesting property of the Old Man of the Andes Cactus enhanced by distance coalescence through microgrooves and finally, a theoretical study of viruses viability in sessile droplets. The first chapter introduces the theoretical framework of wettability and phase changes on surfaces. In the second chapter, we present the self-ejection of condensation droplets from hydrophobic nanostructured microstructures. We modelled analytically the droplets jumping and fabricated surfaces to verify the predictions. The fabricated geometry was inspired by the modelling and the available fabrication techniques. We tested the surfaces in condensation conditions. Using a high frame rate camera coupled with a long working distance microscopy objective, we investigated the growth and ejection transient. We then compared the experimental self-ejection velocity for various structures geometry with our analytical models. In Chapter 3, we investigated the applications of the fabricated surfaces reported in Chapter 2. In Chapter 4, we explore the condensation frosting on the leaf of Cotinus Coggygria, native of our woods and with interesting hydrophobic properties. Covered by wax nanotubules, it exhibits coalescence-induced condensation jumpings that may be a useful cleaning tool. Furthermore, the frost is delayed but not only for the jumping. Surprisingly, at temperatures some degrees below zero, we observed what we called ‘droplet Sliding on Frost bridges’, that further delays frosting. We described the feasibility of this sliding in terms of dynamic contact angles of the surface and contact angles of supercooled water on ice. By capturing high temporal and spatial resolution videos we investigated the sliding on frost and droplet recalescence (fast dendrite growth that partially solidify the liquid). The responsible for the failure of sliding for temperatures from about -8 ° C down appears to be the advancing angle of water on ice that increases with the subcooling rather than the recalescence that blocks the drop in place. These results add a piece to the fundamental research on the supercooled water-ice-vapour interfaces. As it often happens, biological surfaces offer a starting point for the study of fundamental mechanisms and the development of artificial surfaces with optimized properties. In the Chapter 5, the multifunctional roles of hairs and spines in Old Man of the Andes Cactus (Oreocereus trolli) are studied. We study the morphology of the appendages, the hairs wettability, mechanical properties of both, and the dew formation on spines. The longitudinal microgrooves on the spines cause a particular phenomenon of distant coalescence (DC), in which smaller droplets flow totally or partially into larger ones through the microgrooves, with consequent accumulation of water in a few large drops. An earlier study has shown artificial micro-grooved surfaces that exhibit DC are more efficient than flat ones at collecting and sliding dew, and thus these cactus spines could act as soil dew conveyors. The agreement between our analytical model and experimental data verifies that the flow is driven by the Laplace pressure difference between the drops. This allowed us to obtain a general criterion for predicting the total or partial emptying of the smaller drops as a function of the dynamic contact angles of a surface. Based on this criterion, an hydrophilic material with small contact angle hysteresis would allow a greater number of complete drops emptying. The COVID-19 pandemic has raised the problem of contagion from airborne and deposited droplets. In the last chapter, we report the state of the art of experiments on the viability of viruses in deposited droplets. Up to date, it has been experimentally highlighted that the relative viability of some viruses (RV) depends on the material chemistry, temperature, and interestingly, on relative humidity (RH) with a U-shaped trend. One of the current hypotheses is that the cumulative dose of salt concentration (CD) affects RV. We model the RV of viruses in sessile droplets by inserting a RV-CD relation in a model of droplet evaporation. By considering a saline water droplet (one salt) as the simplest approximation of real solutions, we analytically simulate the time evolution of salt concentration, vapor pressure, and droplet volume varying contact angles, droplet sizes, and RH in the range 0–100%. The results elucidate some previously not yet well-understood dynamics, demonstrating how three main regimes—directly implicated in nontrivial experimental trends of virus RV—can be recognized as the function of RH. The proposed approach could suggest a chart of a virus fate by predicting its survival time at a given temperature as a function of RH and contact angle. We found a good agreement with experimental data for various enveloped viruses and predicted in particular for the Phi6 virus, a surrogate of coronavirus, the characteristic U-shaped dependence of RV on RH. Given the generality of the model, once experimental data are available that link the vulnerability of a certain virus (such as SARS-CoV-2) to the concentrations of salts or other substances in terms of CD, it is envisioned that this approach could be employed for antivirus strategies and protocols for the prediction/reduction of human health risks associated with SARS-CoV-2 and other viruses.

Diploma thesis focuses on effect of the bypass factor on design and geometry of the evaporator for the cooling unit of data centre. Effect of the bypass factor on individual design parameters is solved in detail. All dependendecies are captured by using graphs in which s placed a cement on that parameter. In part C, mathematical and physical solutions are demonstrated calculations and processes leading to the design of the exchanger. In the end, evaluation of the calculations is done and there is also showed possible improvements for the practise.