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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Skolbiblioteken i biblioteksplanerna : En innehållsanalys / The school libraries in the library plans : A content analysis

Axelsson, Martina, Pedersen, Sandra January 2020 (has links)
This thesis examines the way cooperation between the schools and   school libraries are described in the library plans in 21 of the municipalities in Sweden. Our selection has been based on geographical spreading. Our used method in this thesis is a content analysis, where both qualitative and quantitative methods have been used. In Sweden, primary school is mandatory and nine years ago it also became statutory for every school to have a school library. The law also says that the principal/head of the school has a responsibility to make sure a collaboration is even possible. Our research also shows that the principal's/head of the schools role is vital for how the collaboration will work. He or she can demand the staff to start working together or arrange for them to be able to get time to plan together. A number of research shows that it’s important with a collaboration between the schools and school libraries, the collaboration can improve the students' study results. It also highlights how the library plan can act as an important strategic document for the libraries. We have used Patricia Monitel-Overalls TLC-models (Teacher-Librarian-Collaboration) for our analysis. In our results we found that both the teachers and librarians often wanted to have a collaboration. Still, not many did and the most common reasons were that none of them really knew what to expect or demand of each other. Another reason was that the picture of what a library can offer and help with was very old fashioned. In other words, they did not know everything a librarian can do or how much the library could help. In conclusion, the library plans need to be more direct with how the schools and school libraries are supposed to work together. That includes both the collaboration, how everyone can communicate and who’s in charge.
52

Experiments In Pool Boiling Heat Transfer And Nucleationdynamics Of High Pressure Refrigerants

Joo, Daniel 01 January 2006 (has links)
A high pressure pool boiling experiment of pressurized R134a is designed and built, utilizing thermochromatic liquid crystal techniques. Liquid crystals thermo-chromatography uses encapsulated liquid crystals that are sensitive to temperature. When exposed to hot temperatures the crystal reflect a blue/violet color, and when exposed to cooler temperatures it reflects a red/orange color. The color value or hue is proportional to its temperature. Using this technique this experiment is capable of studying the physics and thermodynamics of refrigerants under nucleate pool boiling. The main objective of this experiment was the design of the experimental setup. Various designs were tested and validated, of which all incorporated a pressure resistant chamber constructed out of aluminum and glass viewing ports. Design parameters such as the heating element thickness were verified using a transient FEA thermal model. This model, which was developed in ANSYS, verified that this design would be able to capture the thermal response of the thermochromatic liquid crystals. This analysis concluded that a negligible error of 0.02°C is expected due to transient effects. Difficulties were encountered during early stages of development; most notable were imaging limitations such as low camera frame-rates and poor resolution. Since a TLC technique was used to measure the temperature of the boiling surface, a camera system fast enough to capture the thermal response was needed. At bubble frequencies of 30 nucleations per second, it was necessary for the camera to have much higher frame rates. Through the use of two synchronized cameras, the surface temperature, position, size and shape of the bubbles were recorded simultaneously. Two camera systems were designed and tested. The first system consisted of a high speed CMOS camera capable of capturing 1,000 frames per second, and an RBG CCD color camera capable of 30 Frames per second. However, this system was limited the slow frame rate and low resolution of the RBG camera. The second system used two high resolution and fast shutter speed cameras, which were able to capture fast bubble nucleations. This method required the assumption that under constant operating conditions, the path of one bubble was identical to the next. This method was tested utilizing the high speed camera, and was shown that there was less than a .04% deviation from the path any bubble to that of the next. Detailed analysis of nucleating surface temperatures using thermochromatic liquid crystal technique and temporal-temperature response under various heat flux and at 813.6kPa (118Psia) and 882.5kPa (128Psia) was performed. It is seen that temperature distribution is quite varied in each case. At high pressures the size of nucleation site decreases, giving rise to an increase in the surface temperature. Bubble growth is also analyzed through the use of high speed cameras and compared to temperature distributions. Simultaneous temperature and bubble size measurements provided a correlation between bubble growth and heat transfer. Boiling parameters such as bubble frequency, bubble size, and contact area are also analyzed. From the surface temperature plots, the local and average heat transfer coefficients were calculated as a function of time and bubble dynamics.
53

Gymnasielärares syn på skolbibliotekariens roll och samarbetet professionerna emellan : En kvalitativ intervjustudie / Upper secondary school teachers' view of the school librarian's role and the collaboration between the professions : A qualitative interview study

Burman, Linn, Johansson, Hanna January 2023 (has links)
The aim of this study is to develop a deeper understanding of how upper secondary teachers view the role of the school librarian and how these professions collaborate. Although the subject is well researched within Library and information science, there are few studies that illustrate the teacher's perspective and experiences of the school librarian's role, and collaboration between the professions. Thus, the aim of this study is to fill this knowledge gap. The empirical material was collected through eight semi-structured interviews with professional teachers in the Swedish upper secondary school. To highlight how the teachers see the role of the school librarian, Abbott's (1988) theory of professions was applied. Montiel-Overall (2005) teacher and librarian collaboration model (TLC-model) was also chosen, since the aim is to analyze how the professions collaborate with each other. The result and conclusions show that teachers in this study generally have a positive view of the school librarian’s role, and that they mainly describe the librarian's role as a literacy promoter. This is reflected in how the professions collaborate. The majority of the interview participants engage in more superficial collaborative practices, though a few engage in deeper collaboration that include integrated instructions. Despite the positive image of the role, some ambiguities were found regarding what the school librarian's role entail, an aspect that is confirmed by research and literature within the field. The view of the school librarian's role in the school is vital for whether a collaboration takes place and develops.
54

Heat Transfer Augmentation In A Narrow Rectangular Duct With Dimples Applied To A Single Wall

Slabaugh, Carson 01 January 2010 (has links)
Establishing a clean and renewable energy supply is the preeminent engineering challenge of our time. Turbines, in some form, are responsible for more than 98 percent of all electricity generated in the United State and 100 percent of commercial and military air transport. The operation of these engines is clearly responsible for significant consumption of hydrocarbon fuels and, in turn, emission of green house gases into the atmosphere. With such wide-scale implementation, it is understood that even the smallest increase in the operating efficiency of these machines can lead to enormous improvements over the current energy situation. These effects can extend from a reduction in the emission of greenhouse gases to lessening the nation's dependence of foreign energy sources to lower energy prices for the consumer. The prominent means of increasing engine efficiency is by raising the 'Turbine Inlet Temperature' ' the temperature of the mainstream flow after combustion, entering the first stage of the turbine section. The challenge is presented when these temperatures are forced beyond the allowable limits of the materials inside the machine. In order to protect these components, active cooling and protection methods are employed. The focus of this work is the development of more efficient means of cooling 'hot' turbine components. In doing so, the goal is to maximize the amount of heat removed by the coolant while minimizing the coolant mass flow rate: by removing a greater amount of heat with a lower coolant mass flow rate, more compressed air is left in the mainstream gas flow for combustion and power generation. This study is an investigation of the heat transfer augmentation through the fully-developed portion of a narrow rectangular duct (AR=2) characterized by the application of dimples to the bottom wall of the channel. Experimental testing and numerical modeling is performed for full support and validation of presented findings. The geometries are studied at channel Reynolds numbers of 20000, 30000, and 40000. The purpose is to understand the contribution of dimple geometries in the formation of flow structures that improve the advection of heat away from the channel walls. Experimental data reported includes the local and Nusselt number augmentation of the channel walls and the overall friction augmentation throughout the length of the duct. Computational results validate local Nusselt number results from experiments, in addition to providing further insight to local flow physics causing the observed surface phenomena. By contributing to a clearer understanding of the effects produced by these geometries, the development of more effective channel-cooling designs can be achieved.
55

Análisis de los Decretos Legislativos relacionados con los recursos forestales y de fauna silvestre y su vinculación con los pueblos indígenas, principalmente con el derecho a la consulta previa, en el marco de la delegación de facultades legislativas al Poder Ejecutivo, aprobada por el Congreso de la República mediante la Ley N° 29157, para la implementación del Tratado de Libre Comercio con Estados Unidos

Corrales Trigoso, Paula Legna Alexandra 10 April 2017 (has links)
Los Decretos Legislativos relacionados con los recursos forestales y de fauna silvestre y su vinculación con los pueblos indígenas, principalmente con el derecho a la consulta previa, en el marco de la delegación de facultades legislativas al Poder Ejecutivo, aprobada por el Congreso de la República mediante la Ley N° 29157, para la implementación del Tratado de Libre Comercio con Estados Unidos presentan dos posturas; por un lado, las mejoras en la gestión ambiental y por otro lado, si dichas mejoras a través de los Decretos Legislativos vulneran los derechos de los pueblos indígenas, principalmente el derecho a la consulta previa. Cierto es que se ha cuestionado si las medidas legislativas vulneran los derechos de los pueblos indígenas, es que acaso los derechos legislativos, afectan directamente a los pueblos indígenas, entendida esta afectación como un cambio significativo o relevante en la situación jurídica de los pueblos indígenas. Pues la respuesta dependería del caso en concreto puesto que si la norma es de carácter general, y por ende pretende regular la conducta de todos los ciudadanos peruanos, no se afectaría el derecho a la consulta previa de los pueblos indígenas. Sin embargo, si los Decretos Legislativos implican una afectación directa a los pueblos indígenas, se vulneraria a todas luces el derecho a la consulta previa.
56

Conocimientos tradicionales: ley 27811 ¿a quién se está protegiendo?

León Cabezudo, Liz 10 April 2017 (has links)
¿Qué son los conocimientos tradicionales?, ¿a quiénes les pertenecen?, ¿por qué resulta necesaria su protección?, estas son preguntas que surgen usualmente cuándo se hace mención a los conocimientos tradicionales o simplemente se limita su concepto a “son los conocimientos de las comunidades indígenas”, pero sin comprender la verdadera importancia de los mismos.
57

Skolbibliotek - en integrerad del i undervisningen eller en egen ö? : En studie i hur samarbetet mellan skolbibliotekarier och lärare kan främja elevers lärande / School library - an integral part in teaching or an island of its own? : A studie in how the collaboration between school librarians and teachers can promote student learning

Nickel, Kristina January 2024 (has links)
This bachelor’s thesis is written in the scientific field of library- and information science. The purpose of the study is to investigate the collaboration between teachers and school librarians from the perspective of school librarians. Six school librarians have been interviewed regarding their views on the collaboration with teachers. The theoretical framework used in this study is Montiel-Overalls Teacher and librarians collaboration (TLC) with its four models of collaborations and the big five that is described in TLC. The methods used in this study are qualitative interviews and qualitative content analysis. The study shows that collaboration takes place mostly within the models A (coordination) and B (cooperation). Some collaborations have components from model C (integrated instruction) but only one of the school librarians comes near model D (integrated curriculum). There are not much deeper forms of collaboration in the results of this study mostly due to the lack of planning and evaluate together. Limitations for collaboration between school librarians and teachers are lack of time, lack of support from the principal and ignorance from booth teachers and principals of what a school librarian can contribute to the school’s education and student’s learning in collaboration with the schools other teaching staff. All of the school librarians in this study thinks that the principals commitment is very important for legitimizing the school librarians role in schoolwork.
58

Hochverzweigte Polymere als chromatographische Selektoren

Tripp, Sandra 06 January 2015 (has links) (PDF)
Moderne analytische Verfahren ermöglichen eine höchst effiziente Auftrennung und eine selektive Detektion von Zielanalyten. Dies ist vor allem in der Medizin von Bedeutung, da eine frühzeitige Diagnose von Krankheiten in den meisten Fällen zu einer wesentlich erfolgreicheren Behandlung beiträgt. In unserer heutigen Industriegesellschaft werden daher hochsensitive und effiziente Analysemethoden stärker benötigt als je zuvor. Diverse Umweltgifte oder gesundheitliche Schadstoffe gelangen vermehrt in Grundwasser und Umwelt. Eine Analyse ist aufgrund der oft nur geringen Konzentrationen und der Komplexität diverser Proben häufig mit großen Schwierigkeiten verbunden. Obwohl die Sensitivität und Effizienz zur Bestimmung von Krankheitsmarkern (Biomarker) und Schadstoffen immer weiter zunimmt, stoßen selbst höchstsensitive Analysemethoden an ihre Grenzen. Gerade bei kleinsten Konzentrationen an Zielanalyten oder bei komplexen Gemischen ist eine direkte Detektion ohne weitere Vorbehandlung, wie Aufkonzentrierungen oder Markierungen, äußerst schwierig oder nicht möglich. Eine Optimierung dieser Methoden, deren Automatisierung sowie sensitivere Detektorsysteme werden benötigt. Darüber hinaus ist die Entwicklung von neuartigen, selektiveren mobilen und stationären Phasen ein hochinteressantes und umfangreich untersuchtes Forschungsgebiet. Die Verwendung von hochselektiven Additiven, wie Cyclodextrinen, Kronenethern, Mizellen und andere chirale Selektoren in der Hochleistungsflüssigkeitschromatographie (HPLC), Kapillarelektrophorese (CE)[1,2] oder in der Dünnschicht-Chromatographie (TLC)[3] wurde bereits umfangreich untersucht und etabliert. Hochfunktionalisierte Polymere als äußerst spezifische Selektoren mit hoher Selektivität stellen vielversprechende Materialien dar, die ebenfalls eine Optimierung in der HPLC und CE erzielen.[4-9] Der Einsatz von Polymeren in molekular geprägten Matrizen (molecular imprinted polymers, MIP) oder in monolithischen Trennsäulen wird bereits äußerst erfolgreich in der TLC, HPLC und CE genutzt.[7-11] Eine solch hochselektive Säulenmodifizierung bietet eine sehr gute Performance und hervorragende Trennleistungen. Ein Nachteil dieser hochselektiven Modifizierung ist jedoch die Spezialisierung nur auf das jeweilige Problem. Eine universelle Verwendung für komplexe Gemische und eine Fülle von Analyten ist limitiert. Ein sehr vielversprechender Aspekt ist der Einsatz von Polymeren als chirale Selektoren in der stationären wie auch in der mobilen Phase. Die große Anzahl an kommerziell erhältlichen Trennsäulen mit einer Polymermodifizierung und das ständig umfangreichere Angebot solcher Säulen[12] verdeutlichen diesen Trend und zeigen, dass die Nutzung von polymeren Architekturen für eine weitere Optimierung diverse Möglichkeiten bietet. Hochverzweigte Polymere stellen unter den Polymeren vielversprechende Materialien dar, die aufgrund ihrer Vorteile zu einer effektiven Optimierung beitragen können.[12] Die hohe Anzahl an terminalen Gruppen ermöglichen es, gut zugängliche anwendungsorientierte Modifizierungen durchzuführen, um gewünschte Eigenschaften zu generieren. Durch die hohe Variabilität der Polymere selbst und der diversen Modifizierungsmöglichkeiten zeigen maßgeschneiderte Polymere ein enormes Potential und die Möglichkeit hochselektive Wechselwirkungen mit Zielanalyten zu etablieren. Die Modifizierung mit einer Schale um den polymeren Kern ermöglicht weitere Optimierungen für den Einsatz von Kern-Schale-Architekturen. Beispiele hierfür sind unter anderem die Vermittlung höherer Löslichkeit durch eine Modifizierung des hydrophilen/hydrophoben polymeren Kerns zur Etablierung einer äußeren Schale. Ebenso können durch die Modifizierung gezielte Eigenschaften generiert werden, die eine spezifische Interaktion mit Oberflächen oder Wirkstoffen ermöglichen. Die Zielsetzung dieser Arbeit ist die Synthese und die Untersuchung von Kern-Schale-Architekturen als chromatographische Selektoren. Als polymerer Kern wird hochverzweigtes Poly(ethylenimin) (PEI) verwendet, das mit einer Oligosaccharidschale modifiziert wird. Das PEI wird mit den Kerngrößen 5 und 25 kDa verwendet, wodurch eine Untersuchung des Kerneinflusses möglich ist. Weiterhin wird die Dichte der Oligosaccharidschale eingestellt. Dafür wird eine dichte, moderate bis offene und eine sehr offene Oligosaccharidschale um den polymeren Kern generiert. Infolge dessen kann der Einfluss der Schalendichte auf die Interaktion mit Beispielanalyten evaluiert werden. Für die Oligosaccharidschale (OS) werden darüber hinaus drei verschiedene Oligosaccharide (Maltose, Lactose und Maltotriose) verwendet, um den Einfluss der Art der Schale zu prüfen. Durch diese Variationen können 15 unterschiedliche PEI-OS Kern-Schale-Architekturen synthetisiert und untersucht werden. Weiterhin soll der hydrophobe Anteil der Kern-Schale-Architekturen durch die Anbindung von unpolaren Seitenketten an einen PEI-Kern erhöht werden. Auf diese Art und Weise können nicht-kovalente Wechselwirkungen mit lipophilen Systemen untersucht werden. Um polymere Kern-Schale-Architekturen möglichst effizient in der TLC, HPLC und CE einsetzen zu können, ist es essentiell, ihre Eigenschaften und die Art und Weise der Wechselwirkungen zu kennen, die sie mit möglichen Gastmolekülen eingehen. Durch die Untersuchung dieser Wechselwirkungen können Informationen über deren Interaktionen und eine mögliche Manipulation bzw. Optimierung dieser erhalten werden. Ein zielgerichteter und effektiver Einsatz mit diesen Kern-Schale Architekturen kann so vorbereitet werden. [1] T. J. Ward, K. D. Ward, Anal. Chem. 2012, 84, 626-35. [2] W. J. Cheong, S. H. Yang, F. Ali, J. Sep. Sci. 2013, 36, 609-28. [3] M. D. Bubba, L. Checchini, L. Lepri, Anal. Bioanal. Chem. 2013, 405, 533-554. [4] M. Hanson, K. K. Unger, Trends Anal. Chem. 1992, 11, 368-373. [5] J. Kirkland, J. Chromatogr. A 2004, 1060, 9-21. [6] F. Gasparrini, D. Misiti, R. Rompietti, C. Villani, J. Chromatogr. A 2005, 1064, 25-38. [7] A. Martin-Esteban, Trends Anal. Chem. 2013, 45, 169-181. [8] I. Nischang, J. Chromatogr. A 2013, 1287, 39-58. [9] R. D. Arrua, M. Talebi, T. J. Causon, E. F. Hilder, Anal. Chim. Acta 2012, 738, 1-12. [10] P. Jandera, J. Chromatogr. A 2013, 1313, 37-53. [11] F. Svec, J. Sep. Sci. 2004, 27, 1419-1430. [12] M. Tang, J. Zhang, S. Zhuang, W. Liu, Trends Anal. Chem. 2012, 39, 180-194.
59

Läsförståelse: ett kollegialt samarbetsuppdrag? : En kvalitativ intervjustudie med lärare i årskurs tre med fokus på samarbete med bibliotekarier kring läsförståelse / Reading comprehension: a collaborative task? : A qualitative study on collaboration between 3rd grade teachers and school librarians in order to advance students’ achievements in reading comprehension

Krslak, Elvir January 2019 (has links)
In this study, a total of five teachers were interviewed in grade three from four different schools in Stockholm. Three of these schools are located in different suburbs and one school is located in the central part of Stockholm. The starting point of the study is statistics that show a negative development with, in particular, the students who have Swedish as a second language. This study provides an insight into how teachers in grade three of elementary school in Stockholm work with their students to develop reading comprehension. In the study of reading comprehension, this study focuses on the Reciprocal Teaching (RT) method. RT is a well-established reading comprehension strategy designed to bridge the difference between poor readers and good readers. The study shows that not all teachers are familiar with the RT method and also that teachers do not work consistently with all parts of this method. Furthermore, the study also gives an insight into the question of whether the teachers see the librarian as a possible partner in the process. To measure the level at which the teachers collaborate with school librarians, Montiel-Overall's (2005) Teacher Librarian Collaboration (TLC) theory was chosen. TLC theory is an attempt to make practical use of Loertscher’s taxonomy by grouping the low, medium and high levels of collaboration into four models (Model A: coordination, Model B: cooperation, Model C: integrated instruction and Model D: integrated curriculum.) that help define and measure the effect of each model on students’ achievements. This study concludes that the teachers so far haven’t thought about their school librarian as a potential partner with the stated purpose of increasing the students' reading comprehension. The levels of collaboration are predominantly on the low end of the TLC models (Model A: coordination, Model B: cooperation), meaning that teachers and librarians help each other for mutual benefit but no conscious effort is made to plan, teach and evaluate together.
60

Identifications moléculaires des espèces hétéroatomiques et métalliques en lien avec les procédés d’hydrodemetallation et d’hydroconversion. / Molecular identification of heteroatomic and metal species related to hydrometallation and hydroconversion.

Gutiérrez Sama, Sara 26 September 2017 (has links)
La présence d'hétéroatomes et métaux dans des fractions lourdes de pétrole brut peuvent entraîner la désactivation des catalyseurs d’hydrotraitement et d’hydrocraquage. Les composés contenant ces éléments sont connus pour être inclus dans des agrégats macromoléculaires d’asphaltènes, qui sont considérées comme les composants les plus problématiques des produits pétroliers. Ces travaux ont pour objectif d’apporter une meilleure compréhension de l’environnement chimique de ces espèces et des phénomènes d’agrégation pour optimiser les processus de raffinage. Des techniques de séparation comme la chromatographie de perméation de gel ou Gel Permeation Chromatography (GPC), Advanced Polymer chromatographie (APC) et la chromatographie sur couche mince d’haute performance ou High Performance Thin Layer Chromatography (HPTLC) ont été combinées avec des techniques d’analyse élémentaire comme la spectrométrie de masse à plasma à couplage inductif ou Inductively Coupled Plasma Mass Spectrometry (ICP-MS) et la spectrométrie de masse moléculaire d’haute résolution pour la caractérisation des fractions pétrolières lourdes. Les profils de distribution en taille d’espèces qui contiennent du vanadium, du nickel et du soufre, les hétéroatomes et métaux les plus abondants dans les produits pétroliers, ont été déterminés par GPC couplé à une détection élémentaire par ICP MS. Les paramètres ayant le plus d’impact sur la distribution en taille et l’évolution des agrégats dans les solutions de différentes coupes pétrolières ont été optimisés. Cela nous a permis de faire différentes comparaisons, entre de nombreuses charges et effluents de procédés, ainsi que d’autres séries d’échantillons ou de mélanges provenant d’unités-pilotes d’hydrotraitement. Les résultats obtenus ont pu être mis en regard de caractéristiques macroscopiques comme la viscosité. Le couplage du nouveau système APC avec l’ICP MS a été mis au point avec succès. Cette technique a permis de réaliser des cartographies d’échantillons pétroliers plus rapides qu’en GPC tout en consommant moins de solvant. Cependant, les différences des chromatogrammes APC obtenus par rapport aux profils GPC suggèrent des interactions indésirables avec la phase stationnaire, qui ont été l’objet d’une évaluation approfondie.Enfin, un dernier type de séparation a été évaluée. L’HPTLC, qui utilise des plaques à usage unique, peut être appliquée à la séparation de produits lourds par polarité, et ce sans étapes de déasphaltage préalable, contrairement aux colonnes de chromatographie liquide qui peuvent être détériorées à cause de l'adsorption irréversible et de la précipitation des asphaltènes. Différents types de plaques et éluants ont été testés afin de développer une méthode simple pour la séparation des fractions SAR (Saturés, Aromatiques et Résines) des échantillons de distillat sous vide ou Vacuum Gas Oil (VGO). Ce travail avait pour but des migrations en une seule étape et analyse UV qui pourrait être mis en œuvre pour l’analyse de routine dans les laboratoires de contrôle avec une adsorption irréversible réduite. Des résultats très prometteurs ont été obtenus avec l’utilisation de plaques de cellulose pour la séparation des familles de polarité différentes au sein des agrégats d’asphaltènes. Des tests sur l'analyse directe des plaques par Désorption-Ionisation par Électronébulisation (DESI) MS, l'analyse directe en temps réel ou Direct Analysis in Real Time (DART) MS et Ablation Laser (LA) ICP MS ont été effectués. / The presence of heteroatoms and metals in heavy fractions of crude oil can cause the deactivation of hydrotreatment and hydrocracking catalysts. Compounds containing these elements are known to be included in macromolecular asphaltene aggregates, which are considered the most problematic components of heavy oil. This thesis aimed for a better understanding of the chemical environment of these species and on the aggregation phenomenon to optimize refining processes. Separation techniques such as Gel Permeation Chromatography (GPC), Advanced Polymer Chromatography (APC) and High Performance Thin Layer Chromatography (HPTLC) were combined with elementary analysis techniques such as Inductively Coupled Plasma Mass Spectrometry (ICP MS) or high-resolution molecular mass spectrometry for the characterization of heavy fractions of crude oil. Here, the size profiles of species that contain vanadium, nickel and sulfur, the most abundant heteroatoms and metals present in petroleum products, were determined by GPC online with elemental detection by ICP MS. The parameters having the most significant impact on size distribution and the evolution over time of aggregates from solutions of different petroleum cuts were optimized. This allowed the comparison between various feeds and effluents and other series of samples and mixtures from pilot units of refining processes by GPC ICP MS. Results obtained could be related to macroscopic characteristics such as viscosity. Hyphenation of the new APC System to ICP MS has been successfully completed. It allowed the mapping of petroleum samples faster than GPC, therefore with less solvent consumption. However, the differences of the APC chromatograms obtained with respect to the GPC profiles suggested significant unwanted interactions of the highly polar compounds of the petroleum samples with the stationary phase, which have been thoroughly studied. Finally, another type of separation was evaluated. HPTLC, of single-use plates, can be applied to the analysis of heavy petroleum products by polarity without prior deasphalting steps while chromatography columns can be deteriorated because of the irreversible adsorption and asphaltene precipitation. To this end, various types of plates and eluents were tested to develop straightforward SAR (Saturates, Aromatics and Resins) separations of Vacuum Gas Oil (VGO) samples. This method, based on single-step migrations with reduced irreversible adsorption and UV monitoring, could be implemented for routine analysis in control laboratories. Very promising results were obtained by the use of cellulose plates for the separation of different families within asphaltene aggregates. Tests on Desorption ElectroSpray Ionization (DESI) MS, Direct Analysis in Real Time (DART) MS and Laser Ablation (LA) ICP MS analyses of the plates have been performed.

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