Dissertations / Theses on the topic 'Organic matrix'
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Maccarone, Alan T. "Infrared spectroscopy of matrix isolated organic peroxyl radicals." Connect to online resource, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3284492.
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Meyer, Jens. "Transparent organic light emitting diodes for active matrix displays." Göttingen Cuvillier, 2008. http://d-nb.info/994852428/04.
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Lisuwandi, Eko T. 1977. "Feedback circuit for organic LED active-matrix display drivers." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/16849.
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Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.Includes bibliographical references (leaves 44-45).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
A feedback circuit for an Organic Light Emitting Diode (OLED) based display is proposed and demonstrated. An OLED-based flat panel display is brighter, much lower power, has no viewing angle limitation and potentially cheaper compared to available Liquid Crystal (LC) based displays. Despite these advantages, an OLED-based display is not widely commercialized mainly due to its short practical lifetime. The I-V characteristics of the individual OLED pixels vary over time, temperature and processing-dependent parameters. Moreover, the variation is not uniform across an array of OLED pixels, causing OLED based displays to lose brightness accuracy after a few thousand hours of operation. The proposed feedback circuit is used to compensate for the non-uniformities in the individual OLED characteristics. The resulting display leverages the beneficial aspects of OLED display technology, while maintaining pixel uniformity and grayscale reproducibility. A demonstration system is built proving the feasibility of a flat panel display using direct optical feedback. The feedback loop monitors the output light level using a sensor and adjusts the current fed to the pixels to set the output light power to a digitally set reference level. The system shares a single feedback loop among a number of pixels, saving power and real estate. The demonstration system consists of a 5x5 array of LEDs, a CMOS camera, analog pixel circuitry, driver and feedback loop, as well as a digital controller. The demonstration system also shows the feasibility of time-sharing a feedback loop among a number of output devices.
by Eko T. Lisuwandi.
M.Eng.
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Abraham, C. J. "Trace-element analysis of metallic and organic matrix materials exploiting RIMS." Thesis, Swansea University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.635842.
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Sputter initiated Resonance Ionisation Spectroscopy (SIRIS) was used to perform trace analysis for a number of elements in various matrices. The system consisted of a reflection time of flight (ToF) mass spectrometer combined with a duoplasmatron primary ion source which was coupled to a Nd:YAG pumped dye laser. External electronics were constructed to synchronise precisely the timing of the laser pulse, primary ion source and dual channel plate detector. The present set-up allowed the utilisation of the simplest of all ionisation routes, namely the one-colour, two-photon RIS schemes. The elements titanium, chromium, nickel, molybdenum, iron and tin were photo-ionised in the 290-300 nm and 280-290 nm range. Various resonances for these elements were obtained providing valuable information on efficient RIS routes, which could be used in trace analysis. The sensitivity of the RIMS technique was demonstrated by the detection of 15 ppm of iron in a nickel host, with an ultimate detection limit of less than 5ppb. Trace detection of potentially toxic elements such as iron and aluminium in brain homogenate tissue was demonstrated for samples, with concentrations of 100 ppm of aluminium and 400 ppm of iron: detection was possible without isobaric interferences. These elements have been linked to the neurological disorders of Alzheimer's disease and Parkinsonian dementia. In a separate application, the detection of 480 ppm of tin in an insulator of silicone gum is shown, demonstrating the diverse range of samples which can be analysed using RIMS. A brief review of the theoretical modelling for ion sputtering and the process of resonance ionisation is given, including the benefits and limitations of the various methods.
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Shahid, Salman. "Polymer-Metal Organic Frameworks (MOFs) Mixed Matrix Membranes For Gas Separation Applications." Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS141/document.
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Le comportement plastifiant de polymères purs a été bien étudié dans la littérature. Toutefois, il n'y a eu que peu d'études concernant les membranes à matrices mixtes (MMM). Dans le chapitre 2 de cette thèse, le comportement plastifiant de MMM préparés à partir de nanoparticules mésoporeuses Fe(BTC) et du polymère Matrimid® est étudié avec un gaz pur ou en mélange. Les réseaux métaux-organiques (MOF) sous forme particulaires ont présenté une relativement bonne compatibilité avec le polymère. L'incorporation de Fe(BTC) dans du Matrimid® a permis d'augmenter la perméabilité et la sélectivité des membranes. Pour de faibles pressions de 5 bars, les MMM ont une perméabilité au CO2 de 60% plus grande ainsi qu'une sélectivité de 29% plus grande à comparer à la sélectivité idéale de membranes Matrimid®. Il a été observé que la présence de particules Fe(BTC) retardait l'effet plastifiant vers de plus grandes pressions. De plus, cette pression augmente avec le taux de MOF au sein du matériau. Ce retard est attribué à la mobilité réduite des chaînes polymères dans l'entourage des particules Fe(BTC). Egalement, pour des concentrations en MOF plus élevées, les membranes présentent une sélectivité plus ou moins constante sur toute la gamme de pression étudiée. Le chapitre 3 présente ensuite la préparation et le caractère plastifiant des MMMs basées sur trois types de MOFs (MIL-53(Al) (MOF « repirant »), ZIF-8 (MOF « flexible ») and Cu3(BTC)2 (MOF « rigide »)) dispersés dans le Matrimid®. Les performances en gaz pur ou en mélange ont été étudiées en fonction de la quantité de MOF introduite. Parmi les trois systèmes MOF-MMM, les membranes avec le Cu3(BTC)2 ont présenté la plus haute sélectivité alors que les membranes avec du ZIF-8 ont montré une plus grande perméabilité. Ces améliorations sont essentiellement le fait de la structure cristalline du MOF et de son interaction avec les molécules de CO2. Le chapitre 4 décrit la préparation de membranes à base de mélange Matrimid® polyimide (PI)/polysulfone (PSF) contenant des particules de ZIF-8 pour la séparation gazeuse à haute pression. Un mélange optimisé avec un rapport PI/PSF de 3:1 a été utilisé pour une étude sur la stabilité et la performance de ces MMMs incorporant différentes concentration de ZIF-8. PI et PSF étant miscibles, une bonne compatibilité avec les particules de ZIF-8 est observée. Les MMMs PI/PSF-ZIF-8 ont démontré une amélioration significative de la perméabilité en CO2 lors de l'augmentation de la concentration en ZIF-8, ce qui a été attribué à une augmentation modérée de la capacité de sorption et à une diffusion plus rapide au travers des particules de ZIF-8. Lors des mesures en gaz purs, les membranes PI/PSF (3:1) ont présenté une plastification vers 18 bars alors que l'introduction de ZIF-8 repousse cette valeur à 25 bars. En mélange de gaz, les MMMs PI/PSF-ZIF-8 ont abouti à une suppression de la plastification comme l'a confirmé une mesure constante de la perméabilité et de la sélectivité du CH4, et cet effet est plus accentué avec l'augmentation de la concentration en ZIF-8. Les résultats en séparation des gaz avec les MMMs PI/PSF-ZIF-8 montrent une performance supérieure à celle du Matrimid® ce qui laisse augurer un élargissement du spectre d'application de ces membranes, particulièrement pour la séparation du CO2 à haute pression. Dans le chapitre 5, une nouvelle voie de préparation des MMMs via la fusion contrôlée de particules a été introduite. La modification du Matrimid® par du 1-(3-aminopropyl)-imidazole a permis d'améliorer considérablement la compatibilité avec les particules de ZIF-8. Il a ainsi été possible de préparer des MMMs contenant 30% de MOF sans perte de sélectivité. En augmentant la concentration en ZIF-8, les MMMs ont de meilleures performances dans la séparation de mélange CO2/CH4 à comparer au polymère initial. La perméabilité a augmenté de plus de 200% avec une augmentation de 65% de sélectivité pour le mélange CO2/CH4The plasticization behavior of pure polymers is well studied in literature. However, there are only few studies on the plasticization behavior of mixed matrix membranes. In Chapter 2 of this thesis, pure and mixed gas plasticization behavior of MMMs prepared from mesoporous Fe(BTC) nanoparticles and the polymer Matrimid® is investigated. All experiments were carried with solution casted dense membranes. Mesoporous Fe(BTC) MOF particles showed reasonably good compatibility with the polymer. Incorporation of Fe(BTC) in Matrimid® resulted in membranes with increased permeability and selectivity. At low pressures of 5 bar the MMMs showed an increase of 60 % in CO2 permeability and a corresponding increase of 29 % in ideal selectivity over pure Matrimid® membranes. It was observed that the presence of Fe(BTC) particles increases the plasticization pressure of Matrimid® based MMMs. Furthermore, this pressure increases more with increasing MOF loading. This delay in plasticization is attributed to the reduced mobility of the polymer chains in the vicinity of the Fe(BTC) particles. Also, at higher Fe(BTC) loadings, the membranes showed more or less constant selectivity over the whole pressure range investigated. Chapter 3 subsequently presented the preparation and plasticization behavior of MMMs based on three distinctively different MOFs (MIL-53(Al) (breathing MOF), ZIF-8 (flexible MOF) and Cu3(BTC)2 (rigid MOF)) dispersed in Matrimid®. The ideal and mixed gas performance of the prepared MMMs was determined and the effect of MOF structure on the plasticization behavior of MMMs was investigated. Among the three MOF-MMMs, membranes based on Cu3(BTC)2 showed highest selectivity while ZIF-8 based membranes showed highest permeability. The respective increase in performance of the MMMs is very much dependent on the MOF crystal structure and its interactions with CO2 molecules. Chapter 4 described the preparation of Matrimid® polyimide (PI)/polysulfone (PSF)-blend membranes containing ZIF-8 particles for high pressure gas separation. An optimized PI/PSF blend ratio (3:1) was used and performance and stability of PI/PSF mixed matrix membranes filled with different concentrations of ZIF-8 were investigated. PI and PSF were miscible and provided good compatibility with the ZIF-8 particles, even at high loadings. The PI/PSF-ZIF-8 MMMs showed significant enhancement in CO2 permeability with increased ZIF-8 loading, which was attributed to a moderate increase in sorption capacity and faster diffusion through the ZIF-8 particles. In pure gas measurements, pure PI/PSF blend (3:1) membranes showed a plasticization pressure of ~18 bar while the ZIF-8 MMMs showed a higher plasticization pressures of ~25 bar. Mixed gas measurements of PI/PSF-ZIF-8 MMMs showed suppression of plasticization as confirmed by a constant mixed gas CH4 permeability and a nearly constant selectivity with pressure but the effect was stronger at high ZIF-8 loadings. Gas separation results of the prepared PI/PSF-ZIF-8 MMMs show an increased commercial viability of Matrimid® based membranes and broadened their applicability, especially for high-pressure CO2 gas separations. In Chapter 5, a novel route for the preparation of mixed matrix membranes via a particle fusion approach was introduced. Surface modification of the polymer with 1-(3-aminopropyl)-imidazole led to an excellent ZIF-8-Matrimid® interfacial compatibility. It was possible to successfully prepare MMMs with MOF loadings as high as 30 wt.% without any non-selective defects. Upon increasing the ZIF-8 loading, MMMs showed significantly better performance in the separation of CO2/CH4 mixtures as compared to the native polymer. The CO2 permeability increased up to 200 % combined with a 65 % increase in CO2/CH4 selectivity, compared to the native Matrimid®. Chapter 6 finally discussed the conclusions and directions for future research based on the findings presented in this thesis
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Ameye, Laurent. "Control of biomineralization in echinoderms :ultrastructure and cytochemistry of the organic matrix." Doctoral thesis, Universite Libre de Bruxelles, 1999. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211943.
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Ude, Mba. "Supercritical fluid extraction of organic species through polymeric systems." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314376.
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Franks, Jeff. "Sample introduction into ICP-MS systems." Thesis, University of Hull, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262437.
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Xie, Wanqin Ph D. Massachusetts Institute of Technology. "Free approximation of transport properties in organic system using Stochastic Random Matrix Theory." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/93040.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Chemistry, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 44-48).
The proposed research is a study and application of Stochastic analysis- Random Matrix Theory(RMT) to fast calculate the transport properties of large static systems with relatively large disorder in mesoscopic size. As a major topic of Random Matrix Theory(RMT), free convolution managed to approximate the distribution of eigenvalues in an Anderson Model.So the next step is trying to expand RMT to approximate other quantities, such as transmission probability, conductivity and etc. Due to the eigenvectors' shifts, RMT works well only for small disorder. System with larger disorder requires to take in account of the changes in eigenvectors directly or through other approximations of the eigenvectors.
by Wanqin Xie.
S.M.
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Keller, Christopher. "Photolysis of 1-(4-azidomethyl-phenyl)-ethanone and matrix/LFP studies of 2-benzoyl-3-methyl-2H-azirine." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1121442210.
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Silva, Vitor Paulo Andrade da. "Application of solid-phase microextraction technique to the determination of pesticides and evaluation of matrix effect on water." Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=16812.
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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorThis paper investigates a strategy as a quality control parameter, using standard surrogate and determination of an relation factor (Rf) for determination of pesticides parathion-methyl, chlorpyrifos and cypermethrin in aqueous environmental matrices with different characteristics: river water, estuarine, seawater and weir, using technique SPME-GC-FID. Pesticides were susceptible to matrix effects promoted by environmental samples. A decrease in recovery was observed for the pesticide while the complexity of the aqueous matrix tends to increase. The salinity and organic matter appear to be major sources of interference in the method. To the methyl-parathion, the matrix effect was more pronounced for samples with higher salt concentrations. For chlorpyrifos, in medium and high levels, the Rf value for estuarine matrices, marine and weir were statistically similar. For cypermethrin, statistical equality occurred in estuarine headquarters in medium and high levels of concentration. This indicates proportional behavior between the pesticide and the standard surrogate, suggesting that a single value of Rf can be used as a correction factor for any of these matrices used.
Este trabalho investiga uma estratÃgia como parÃmetro de controle de qualidade, usando padrÃo surrogate e determinaÃÃo de um fator de relaÃÃo (Rf) para a determinaÃÃo dos pesticidas metil-paration, clorpirifÃs e cipermetrina em matrizes ambientais aquosas com distintas caracterÃsticas: Ãgua de rio, estuÃrio, marinha e de aÃude; usando a tÃcnica de SPME-GC-FID. Os pesticidas foram suscetÃveis ao efeito matriz promovido pelas amostras ambientais. Observou-se que esse efeito tendeu a aumentar com o aumento da complexidade da matriz. A salinidade e a matÃria orgÃnica parecem ter sido as principais fontes de interferÃncia no mÃtodo. Para o metil-paration, as amostras com maiores teores salinos exerceram efeito matriz mais pronunciado. Para o clorpirifÃs, em nÃveis mÃdio e alto, o valor de Rf para matrizes estuarina, marinha e de aÃude foram estatisticamente similares. Para a cipermetrina, a igualdade estatÃstica ocorreu em matrizes estuarinas em nÃveis mÃdios e altos de concentraÃÃo. Isso indica comportamento proporcional entre o pesticida e o padrÃo surrogate, sugerindo que um Ãnico valor de Rf pode ser usado como fator de correÃÃo para qualquer uma dessas matrizes utilizadas.
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Chafin, Raymond William II. "Torlon® and Silicalite Mixed Matrix Membranes for Xylene Isomer Purification." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14562.
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Organic/inorganic materials have a high potential to enable major advances in membrane performance. It has previously been impossible to develop polymeric systems with adequate transport properties for xylene purification. Zeolite membranes have been created with the appropriate selectivities; however low productivity, low mechanical durability, and high capital costs have kept these materials from being utilized. So-called mixed matrix hybrid organic/inorganic membranes combine the mechanical durability and cost effectiveness of polymeric membranes with the enhanced performance of zeolitic structures. This project will focus on investigating polymeric and molecular sieve materials for mixed matrix membrane use in xylene isomer separation as a model system. Torlon polyamide-imide has unique properties that should be potentially useful in a mixed matrix composite. Silicalite will be investigated as the dispersed phased given its proven applicability with xylene isomers.
The overarching goal is to establish an approach for creation of mixed matrix materials that can be broadly applied to challenging organic separations. This project has three specific goals: (1) characterization of Torlons inherent properties, processing ability, and important transport potential, (2) characterization of zeolite matching properties and the effect of interfacial engineering on these properties, and (3) development of appropriate approaches to combine the sieve and polymer to obtain a hybrid material with properties that match theoretically predicted separation property enhancements relative to the neat polymer. High temperature pervaporation will be used to evaluate material transport properties, as this experimental setup closely mimics the high activity vapor streams found in many industrial xylene processes. The results of this research will be used to develop a protocol for development of future mixed matrix membranes that may be applied to a variety of organic liquid systems.
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Nolan, Michelle Louise. "Proteins of the organic matrix of dentine and calcium transport in MDPC-23 cells." Thesis, University of Liverpool, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.510965.
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Chen, Li. "Speciation of uranium and organic compounds on solid matrix studied by supercritical fluid extraction." FIU Digital Commons, 1996. http://digitalcommons.fiu.edu/etd/2137.
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The liquid extraction and spectrophotometric quantitation of uranium from different solid matrices is compared to supercritical fluid extraction (SFE) using various combinations of 2,2-dimethyl-6,6,7,7,8,8,8-heptafluoro-3,5-octadione (FOD), tri-n-butylphosphate (TBP), ethanol, and carbon dioxide measuring the UV absorption of the uranium-FOD complex. The matrix is shown to have a tremendous effect on the extractability of uranium from different solid matrices. Compared to liquid extraction, the SFE method yields higher recoveries, is significantly faster, is of equal or greater precision, and greatly reduces the amount of organic solvents used. In the second part of this work, the speciation of hydrophobic organic compounds (HOCs) in ancient sediments is studied by stepwise high temperature SFE and comparisons made to thermodesorption and soxhlet extraction. High temperature SFE recovers significantly more HOCs compared to soxhlet extraction. For low molecular weigh compound thermodesorption is the dominant mechanism whereas for high molecular weight compounds the mechanism is a combined effect of thermodesorption and solubility in the supercritical fluid.
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Ayres, Neil. "The polymerisation of vinyl monomers via transition metal mediated living radical polymerisation from an insoluble cross-linked polymer matrix." Thesis, University of Warwick, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250975.
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Kadam, Pritam Eknath [Verfasser], Wolfram [Gutachter] Sander, and Gerald [Gutachter] Dyker. "Matrix isolation of highly reactive organic intermediates / Pritam Eknath Kadam ; Gutachter: Wolfram Sander, Gerald Dyker." Bochum : Ruhr-Universität Bochum, 2017. http://d-nb.info/1138835412/34.
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Khdhayyer, Muhanned. "Mixed matrix membranes comprising metal organic frameworks and high free volume polymers for gas separations." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/mixed-matrix-membranes-comprising-metal-organic-frameworks-and-high-free-volume-polymers-for-gas-separations(172f6a4f-a531-44ae-979c-bbbd170f33db).html.
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This research aimed to develop new composite membranes using a polymer of intrinsic microporosity (PIM-1) and metal organic frameworks (MOFs) for use in gas separations. PIM-1 was successfully synthesised using the high temperature method (40 min, 160 oC) and the resulting polymer was cast into membranes. PIM-1 membranes were chemically modified by reacting hexamethylenediamine (HMDA) with the nitrile group of PIM-1 to form HMDA-modified PIM-1 membranes. Surfaces of PIM-1 membranes were also modified by basic hydrolysis to form amide-modified PIM-1 membranes. These polymer materials were characterized by different techniques (GPC, NMR, ATR-IR, TGA, Elemental analysis and nitrogen sorption analysis). In addition, eight MOF materials [MIL-101(Cr), ED-g-MIL-101(Cr), TEPA-g-MIL-101(Cr), MIL-101(Cr)-NH2, MIL-101(Al)-NH2, UiO-66(Zr), UiO-66-NH2 and UiO-66(COOH)2] were successfully synthesized. They were chosen due to having high surface areas and large porosity. These MOF compounds were characterized using PXRD, SEM, TGA, and low pressure N2.Successful PIM-1/MOF MMMs were fabricated utilising PIM-1 and the MOFs outlined above with various loadings. The highest MOF loading achieved was 28.6 wt. %, apart from MIL-101(Cr)-NH2, for which it was 23.1 wt. %, and MIL-101(Al)-NH2, for which it was 19.8 wt. %. The morphology of MMMs was characterized by scanning electron microscopy (SEM), proving the dispersion of MOF fillers. Novel PIM-1 supported MOF membranes were successfully prepared by depositing ZIF-8 and HKUST-1 layers on the surfaces of unmodified and modified PIM-1 membranes. These materials were characterized using PXRD, SEM, ATR-IR and SEM-EDX. Gas permeation properties of the MOF/PIM-1 MMMs and PIM-1 supported MOF membranes were determined using a time lag method. Most MMMs tested showed an increase in the permeability and stable selectivity as the MOF amount was increased. However, this was not true for MIL-101(Al)-NH2, where the permeability and selectivity decreased. In contrast, PIM-1 supported ZIF-8 and HKUST-1 membranes caused a sharp decrease in the permeability and increase in the selectivity.
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Khan, Mohd Yahya. "Identification and Correlation of Disinfection Byproducts and Total Organic Halogen Precursors in a Biofilm Matrix." University of Toledo / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1404662994.
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Nayak, Nayan Nagesh. "Development of mixed matrix membranes with metal - organic framework and ionic liquids for biogas upgrading." Master's thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/10419.
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Dissertation presented to Faculdade de Ciências e Tecnologia, Universidade Nova
de Lisboa for obtaining the master degree in
Membrane EngineeringThe EM3E Master is an Education Programme supported by the European Commission, the European Membrane Society (EMS), the European Membrane House (EMH), and a large international network of industrial companies, research centers and universities
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Abood, Ahmed T. "Source Apportionment Analysis of Measured Volatile Organic Compounds in Corpus Christi, Texas." Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc500059/.
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Corpus Christi among of the largest industrialized coastal urban areas in Texas. The strategic location of the city along the Gulf of Mexico allows for many important industries and an international business to be located. The cluster of industries and businesses in the region contribute to the air pollution from emissions that are harmful to the environment and to the people living in and visiting the area. Volatile organic compounds (VOC) constitute an important class of pollutants measured in the area. The automated gas chromatography (Auto GC) data was collected from Texas Commission of Environmental Quality (TCEQ) and source apportionment analysis was conducted on this data to identify key sources of VOC affecting this study region. EPA PMF 3.0 was employed in this sources apportionment study of measured VOC concentration during 2005 - 2012 in Corpus Christi, Texas. The study identified nine optimal factors (Source) that could explain the concentration of VOC at two urbane monitoring sites in the study region. Natural gas was found to be the largest contributor of VOC in the area, followed by gasoline and vehicular exhaust. Diesel was the third highest contributor with emissions from manufacturing and combustion processes. Refineries gases and evaporative fugitive emissions were other major contributors in the area; Flaring operations, solvents, and petrochemicals also impacted the measured VOC in the urban area. It was noted that he measured VOC concentrations were significantly influenced by the economic downturn in the region and this was highlighted in the annual trends of the apportioned VOC.
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au, jeremy shaw@uwa edu, and Jeremy Shaw. "Biomineralisation processes in the radula teeth of the chiton Acanthopleura hirtosa (Mollusca: Polyplacophora)." Murdoch University, 2007. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20080703.163505.
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A detailed row by row investigation of major lateral tooth cusp mineralisation, together with the concomitant development of the superior epithelial tissue surrounding the teeth of the chiton Acanthopleura hirtosa has been undertaken using a combination of light microscopy, and scanning and transmission electron microscopy. A holistic approach has been adopted that encompasses observations over a range of spatial scales, from whole radula mineralisation processes to those occurring within individual tooth cusps at various stages of development. In addition, mineralisation in radulae from freshly collected animals has been compared to that of animals maintained for extensive periods within a newly developed iron limited system, which restricts radula mineralisation without impeding the formation of the organic matrix.
An evaluation of the iron limitation technique has revealed that maintaining specimens of A. hirtosa within an iron poor environment results in a significant departure from the normal pattern of mineralisation in these animals. As a consequence of iron limitation, there is an obvious increase in the number of unmineralised tooth rows in addition to associated alterations in structure and composition at all stages of tooth development.
In normal specimens of A. hirtosa, the onset of mineralisation in the tooth cusps occurs following the prior accumulation of iron at the junction zone and the sudden accumulation of iron containing granules in the cusp epithelium at tooth row 13. The superior epithelium surrounding the tooth cusps undergoes a series of developmental changes leading up to, and following, the onset of mineralisation. In particular, the abundance of mitochondria within the apical cusp epithelium increases, presumably in order to provide the ideal conditions of pH, and thus solubility, needed for the supersaturation of iron and its nucleation at row 13. Once mineralisation has commenced, the microvilli attached to the cusps develop rapidly, and are suggested to do so in order to facilitate the transport of iron, and thereby ensure that a high concentration gradient of this element into the cusps is maintained.
The delivery of iron into the cusps occurs from two fronts, the first from the superior epithelium via the posterior surface, and the second from the junction zone via an internal pathway situated along the lepidocrocite boundary between the magnetite and core regions of the tooth. The existence of a plume of elements between this internal mineralisation pathway and the junction zone, provides the first direct evidence that the junction zone is involved in the storage and release of elements for cusp mineralisation. Data from iron limited radulae also indicate that iron continues to be deposited at the junction zone in preference to the superior epithelium or cusps, despite the disruption of mineralisation, highlighting the importance of this region in the mineralisation process.
Iron reinstatement experiments have also shown that the internal pathways of iron delivery within the organic matrix remain viable, despite prolonged periods of iron limitation. In addition, the reinstatement of iron has revealed that the plumes, situated between the junction zone and internal mineralising pathway of the cusp, stem from the centre of the plate like junction zone, directly above the stylus canal, a tube like cavity situated within the styli of each major lateral tooth.
An in depth study of the stylus canal has revealed that cells within the canal are remarkably similar to those of the epithelium surrounding the cusps, suggesting that this structure may also be involved in the delivery of ions to the junction zone. The stylus canal is shown to be present in the major lateral tooth cusps of 38 chiton species distributed worldwide, and is therefore likely to be a feature common to all chitons. The presence of the canal, and indeed its absence from the bases of all remaining non iron mineralised teeth, irrespective of chiton species, also points strongly to a functional relationship between the stylus canal and tooth cusp mineralisation.
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Benzaqui, Marvin. "Synthesis of Metal-Organic Framework nanoparticles and mixed-matrix membrane preparation for gas separation and CO2 capture." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLV075/document.
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La séparation CO2/N2 et H2/CO2 permet de limiter le rejet de CO2 dans l’atmosphère issu des gaz industriels et les membranes présentent de nombreux avantages tant sur le plan économique que pratique. Les membranes polymère sont faciles à mettre en forme mais un compromis entre perméabilité et sélectivité doit généralement être trouvé : pour améliorer les performances, des membranes à matrice mixte (MMM) incorporant des MOFs (matériaux hybrides poreux cristallisés) dispersés dans la phase polymère ont été proposées. A la différence des matériaux poreux inorganiques, les MOFs ont une meilleure compatibilité avec la matrice polymère du fait de leur caractère hybride organiqueinorganique. Dans le cadre de cette thèse, des polycarboxylates de Fe3+ et Al3+ poreux, stables à l’eau, et possédant de bonnes propriétés d’adsorption sélective du CO2 ont été synthétisés en milieu aqueux et mis à l’échelle de quelques grammes. Deux nouveaux polycarboxylates de Fe3+ poreux fonctionnalisés par des fonctions -COOH libres ont été obtenus à température ambiante. Pour l’un d’entre eux, la structure a été déterminée par diffraction des rayons X. Une deuxième partie de la thèse a été consacrée à la synthèse de nanoparticules de MOFs avec un bon rendement. Une partie importante de ce travail a porté sur le contrôle de la taille et la morphologie des nanoparticules de MIL-96(Al). Ce travail a conduit à la préparation de MMMs à base de MIL-96(Al) dont les performances sont supérieures à la membrane pure polymère pour la séparation CO2/N2. La dernière partie de ce travail de thèse a porté sur l’étude physico-chimique de la compatibilité entre le ZIF-8 et deux polymères (PVA et PIM-1). Ce travail a consisté à effectuer une caractérisation complète de solutions colloïdales MOFs/polymère en couplant plusieurs techniques (DLS, TEM, SAXS). Cette étude a montré que la compatibilité MOF/polymère est très dépendante de la chimie de surface des MOFs et des propriétés physico-chimiques du polymère (rigidité, caractère hydrophile/hydrophobe…)CO2 capture and storage (CCS) is of high economical and societal interest. CO2/N2 andH2/CO2 separations are able to limit atmospheric CO2 emissions produced by industrial exhausts andmembranes present numerous economical and practical advantages. Polymer membranes are easy toprocess and possess interesting mechanical properties. However, there is a trade-off to make betweenpermeability and selectivity. Mixed-matrix membranes (MMM) based on MOFs (porous crystallinehybrid materials) have been proposed to boost the performances of polymer membranes for CO2capture. In comparison to other inorganic porous materials, one may expect that the compatibilitybetween MOFs and polymers is enhanced due to the hybrid character of MOFs.In this work, porous water stable polycarboxylate MOFs based on Fe3+ and Al3+ with promisingproperties for CO2 adsorption were synthesized for large-scale production using water as the mainsolvent. Two new porous polycarboxylate Fe3+ MOF bearing free -COOH groups in the frameworkwere obtained at room temperature as nanoparticles. The crystallographic structure of one of thesematerials was determined by single crystal X-ray diffraction. A second part of the thesis was devotedto the synthesis of MOFs nanoparticles with good yield. We focused our attention on the control of thediameter and morphology of MIL-96(Al) nanoparticles. This study led to the preparation of MMMsbased on MIL-96(Al) with promising properties for CO2/N2 separation. Finally, the compatibilitybetween MOF particles and polymers was studied for two systems (ZIF-8/PIM-1 and ZIF-8/PVOH),showing the influence of the surface chemistry of MOFs and the physico-chemical properties ofpolymer on the matching between MOFs and polymers
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Ghanizadeh, Amin [Verfasser]. "Experimental study of fluid transport processes in the matrix system of organic-rich shales / Amin Ghanizadeh." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2014. http://d-nb.info/1048647072/34.
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Brown, Denise Marie Pfaender Frederic K. "Pyrene availability as determined by the interactions of natural organic matter with the soil mineral matrix." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2006. http://dc.lib.unc.edu/u?/etd,686.
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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2006.Title from electronic title page (viewed Oct. 10, 2007). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Environmental Sciences and Engineering, School of Public Health." Discipline: Environmental Sciences and Engineering; Department/School: Public Health.
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Streiter, Martin [Verfasser], Carsten [Akademischer Betreuer] Deibel, Carsten [Gutachter] Deibel, and Georgeta [Gutachter] Salvan. "Chromophore-Matrix Interaction in Organic Semiconductors / Martin Streiter ; Gutachter: Carsten Deibel, Georgeta Salvan ; Betreuer: Carsten Deibel." Chemnitz : Technische Universität Chemnitz, 2020. http://d-nb.info/121991018X/34.
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Castro, Gutierrez Natalia. "Incorporation and release of organic volatile compounds in a bio-based matrix by twin-screw extrusion." Phd thesis, Toulouse, INPT, 2016. http://oatao.univ-toulouse.fr/16006/1/Castro_Natalia.pdf.
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Nowadays, scientific and political communities are focused on ways to better preserve and manage the natural resources of our planet. In order to reduce consumption of fossil resources, and to develop more environmentally friendly industrial processes, the industry of flavors and fragrances became interested in developing new bio-based encapsulating materials. In the present work, maltodextrins have been chosen as main component of the matrix, and pea protein isolate and a modified starch were selected as compatibilizing additives. The incorporation of volatile odorant compounds and the elaboration of the new bio-based delivery systems were performed, all in one single step, by low temperature twin-screw extrusion. The physicochemical, thermal and morphological properties of these matrices were studied, as well as the encapsulation efficiency and the release profile of the active compounds. These investigations have led to a better understanding of the impact of the formulations and of the incorporation of the active compound on the process parameters. The interactions between the wall and the encapsulated materials were also analyzed. The characteristics of the new bio-based delivery systems and the established extrusion process conditions were found to be very promising to be employed in the field of perfumery.
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Zhang, Xiaoming. "Explore the Formation of Triplet Nitrene - A Potential Intermediate for Building Organic Magnets." University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1353156258.
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Gabrion, Xavier. "Contributions à la caractérisation d'un matériau composite thermoplastique thermostable : Application à des structures cylindriques sous sollicitations multiaxiales." Thesis, Besançon, 2014. http://www.theses.fr/2014BESA2012.
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Ce travail de thèse, en partenariat avec l’entreprise ALSTOM, s’inscrit dans une logique de remplacement de pièces industrielles en alliage métallique par des pièces composites pour l’allègement des structures. L’objectif est de contribuer à l’écriture de règles de dimensionnement permettant au partenaire industriel de certifier des pièces structurales annulaires réalisées en composite à matrice thermoplastique thermostable (TPTS) renforcée par des fibres de carbone pour des applications embarquées sur machine tournante. Il s’agit plus exactement de déterminer la durée de vieen fatigue de ces pièces, en particulier en présence d’endommagement, et lorsque celles -ci sont soumises aux chargements inertiels et thermiques de service.Au cours de ce travail de thèse, une méthodologie a été développée afin de répondre à cette demande. La stratégie a consisté à reproduire,à l’échelle d’éprouvettes de laboratoire, l’état de contrainte multi-axial et l’endommagement auxquels la structure industrielle est soumise, et ce en développant et optimisant un essai de traction sur des éprouvettes annulaires entaillées. Les essais multi axiaux plus classiques mettant en œuvre des sollicitations par pression interne présentent effectivement de nombreux problèmes techniques et sécuritaires lorsqu’ils doivent être mis en œuvre à chaud.Une fois la configuration d’essai sur anneau optimisé par simulation numérique, des essais ont été réalisés afin de confirmer l’apparition des endommagements escomptés à l’aide de techniques de contrôle non-destructif. Les essais cycliques réalisés dans cette configuration ont montré une excellente résistance du matériau en fatigue, en particulier pour un ratio de chargement R de 0.5, proche des conditions de service. Les résultats ont également soulignés le fort potentiel restant de ces structures, même après un grand nombre de cycles de chargementThe objective of this thesis work, in partnership with ALSTOM Company, is to contribute to the writing of design rules in order to qualify and certify annular structures made of thermostable thermoplastic matrix composite reinforced by carbon fibre. These structures are used in rotating machines for embedded applications.This work proposes an innovative methodology to achieve this goal. It consists in reproducing, at the scale of a laboratory specimen, the multiaxial stress and damage states to which the industrial structure is subjected in-service byoptimizing a tensile test on annular notched specimen. More conventional multiaxial tests, based on internal pressureand tensile loading are particularly unsafe and difficult to be performedwhen implemented at elevated temperature.After the optimisation of the ring configuration by numerical simulation, experimental tests were performed to validatethe appearance of the expected damage under loading. Damage was characterized using non-destructive techniques suchas acoustic emission and infrared thermography. The cyclic tests achieved using this configuration showed high fatiguestrength of this material, in particular for a ratio R of 0.5 (equivalent to thein-service ratio). The results also highlight thegreat remaining strength and rigidity of these structures, even after a large number of cycles
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Svora, Petr. "Studium chování kompozitních profilů s polymerní matricí a dlouhovláknovou anorganickou výztuží." Doctoral thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-233788.
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During a whole period of time which fibre-reinforced polymers have been used in the building industry, in dominating bonding agent has been the organic resins. There is no doubt about their advantages, but at the same time, they have two weaknesses: they are not fire resistant and they have no resistance to high temperature. Those are the reasons why the research on alternative materials which could replace organic matrix has been undertaken. The goal of the work is to maintain mechanical properties of fibre-reinforced polymer with organic matrix. Of course, an emphasis is placed to fulfilling ecological standards which are required from ecological material. An aluminosilicate inorganic matrix can meet them all. It is non-flammable, does not produce any toxic matter in contact with fire and the energy consumption during production process is lower than in case of the organic matrix. This work includes study and analysis of selected raw materials as well as their influence and impact on final reaction products which are created in inorganic matrix. A part of this work is also a design of the inorganic matrix recipe.
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Duca, Clara. "Effect of water matrix on Vacuum UV process for the removal of organic micropollutants in surface water." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/52252.
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UV-based advanced oxidation processes (UV-AOPs) have been demonstrated as effective technologies
for the removal of micropollutants in water. One promising UV-AOP is Vacuum UV (VUV), which relies on the formation of hydroxyl radicals (HO•) by the photolysis of water induced by VUV photons. TiO₂/UV photocatalysis is another promising AOP. Both VUV and UV photocatalysis are greatly affected by the water matrix, inorganic ions and natural organic matter (NOM). Water constituents can absorb the UV and VUV radiations, they can act as HO• radicals scavengers, and can produce radicals when photolyzed.
The main objective of this research was to study the effects of water matrix on the efficiency
of VUV for the degradation of micropollutants (with atrazine as a model contaminant). First, the
absorbance of radiation at 254 nm and 185 nm was measured in the presence of different ions
and NOM. All the inorganic ions showed a molar absorption coefficient equal to zero at 254 nm
except nitrate with a ɛ= 3.51 M−¹ cm−¹. On the other hand, at 185 nm all the ions absorbed
185 nm radiation, with chloride showing the highest absorption coefficient ɛ=2791 M−¹ cm−¹.
NOM showed a high absorption coefficient at both 254 and 185 nm ranging from 116 to 638 M−¹
cm−¹ at 254 and from 1137 to 1537 M−¹ cm−¹ at 185 nm). Second, the HO• scavenging effects
of different components were evaluated; nitrate showed a detrimental effect both with UV/H₂O₂
and with VUV. The presence of 50 ppm of bicarbonate reduced the degradation rate of atrazine
considerably. Sulfate seemed to photolyze at 185 nm to form HO•. NOM was found to be a strong
HO• scavenger : in the presence of 9 ppm (DOC) NOM, less than 1% of the HO radicals were available to react with atrazine. The next component of this work involved developing a method for the measurement of quantum yield of atrazine at 185 nm. This allowed to measure the degradation of atrazine due to photolysis only. Finally, this research investigated the combination of VUV with TiO₂/UV. The results showed that incorporating photocatalysis cannot improve significantly the
efficacy of VUV.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
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Foti, Federico. "Effect of the Environment on the Fatigue Behaviour of Textile Organic Matrix Composite Materials for Aircraft Applications." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2017. http://www.theses.fr/2017ESMA0031/document.
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Les composites à matrice organiques (CMO) et fibre de carbone sont de plus en plus employés dans la réalisation de structures « tièdes » (aubes de fan, nacelles …) ; ces pièces peuvent être soumises, en service, à la fatigue mécanique, au cyclage thermique et à la fatigue thermo-mécanique. Bien qu’il existe une littérature consistante sur le comportement en fatigue des composites tissés, l'interaction entre fatigue et la dégradation liée à l'environnement à haute température n’a pas été encore bien exploitée. Le couplage entre les effets de la thermo-oxydation, le comportement mécanique (viscoélastique, viscoplastique) de la matrice organique à températures élevées et la dégradation par fatigue peut être néfaste pour le composite.Le but de ce travail est de caractériser et de modéliser - pour les composites tissés C/matrice organique - le comportement thermomécanique, l'apparition et le développement de l’endommagement liés aux mécanismes mécaniques cycliques (fatigue) sous environnement contrôlé (température et gaz).Une étude préliminaire sur un composite stratifiée [02/902]s a été menée pour pouvoir analyser les effets de l’environnement sur une architecture simple. La corrélation d’image numérique (CIN) et des scans μ-tomographiques (μCT) ont été employés pour le suivi et la caractérisation de l’endommagement de fatigue de composites tissés 2D à architecture complexe pour applications aéronautiques. Les effets de l’environnement sur la dégradation par fatigue ont été également explorés.L'objectif à long terme de cette étude est de fournir des outils expérimentaux et numériques pour renforcer la compréhension et la modélisation du couplage mécanique/endommagement/environnement pour la prédiction de la durée de vie et pour la proposition de protocoles d’essais accélérés réalistes de pièces « tièdes » en CMOIn the next future, the employment of organic matrix/carbon fibre composites (OMC) is foreseen for the realization of “hot” structures: these parts may be subjected, in service, to mechanical fatigue (e.g. fan blades turbo-engines), thermal cycling and thermo-mechanical fatigue (e.g. aircraft structural parts). Though there is a consistent literature concerning the fatigue behaviour of woven composites, the interaction between fatigue and environmental degradation at high temperature has been poorly explored. Coupling between thermo-oxidation effects, mechanical (viscoelastic, viscoplastic) behaviour of the polymer matrix at high temperatures and degradation due to fatigue may be highly detrimental for the material. This work aims at characterizing and modelling - for carbon fibre/organic matrix (polyimide) textile composites – the thermomechanical behaviour, the onset and the development of damage related to cyclic mechanical mechanisms (fatigue) under controlled (temperature and gas) environment.A preliminary study on a cross-ply laminate [02/902]s has been carried out in order to analyse the environmental effect on a model sample. Digital Image Correlation (DIC) and μ-Computed Tomography (μCT) have been used to monitor and characterize the fatigue damage of 2D woven composites for aeronautical applications. The environmental effect on fatigue degradation have been also explored.The long-term aim of the study is to provide experimental and numerical tools to strengthen the understanding and the modelling of mechanics/damage/environment coupling for durability prediction
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Adams, Ryan Thomas. "High molecular sieve loading mixed matrix membranes for gas separations." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/39470.
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Traditional gas separation technologies are thermally-driven and can have adverse environmental and economic impacts. Gas separation membrane processes are not thermally-driven and have low capital and operational costs which make them attractive alternatives to traditional technologies. Polymers are easily processed into large, defect-free membrane modules which have made polymeric membranes the industrial standard; however, polymers show separation efficiency-productivity trade-offs and are often not thermally or chemically robust. Molecular sieves, such as zeolites, have gas separation properties that exceed polymeric materials and are more thermally and chemically robust. Unfortunately, formation of large, defect-free molecular sieve membranes is not economically feasible. Mixed matrix membranes (MMMs) combine the ease of processing polymeric materials with the superior transport properties of molecular sieves by dispersing molecular sieve particles in polymer matrices to enhance the performance of the polymers.
MMMs with high molecular sieve loadings were made using polyvinyl acetate (PVAc) and various molecular sieves. Successful formation of these MMMs required substantial modifications to low loading MMM formation techniques. The gas separation properties of these MMMs show significant improvements over PVAc properties, especially for high pressure mixed carbon dioxide-methane feeds that are of great industrial relevance.
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West, Kaydee Jo. "Optimizing Methods for Extraction of Organic Compounds from Molluscan Shells." Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6430.
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Mollusk shells contain proteins within and between the crystals of calcium carbonate. These organic molecules play an important role in biomineralization and shell function, and their stable isotope ratios of carbon and nitrogen are also thought to record important ecological information about the animal's diet and nutrient sources. These proteins can be preserved for millions of years, offering potential insight into pre-anthropogenic ecological conditions. However, shell organics in older shells are typically recovered in reduced abundances due to leaching and remaining organics are often converted from insoluble proteins to soluble, free amino acids, making them difficult to detect and recover. Therefore, demineralization and organics-capture methods must be optimized for yield to extract much-needed ecological information from older shells. This project compared insoluble and soluble organic yields of modern gastropod Strombus alatus shells demineralized with acids of varying concentrations and temperatures. Results suggested that demineralizing shell fragments with 0.1 M HCl at a ratio of 0.9 L HCl/g of shell was optimal. Average percent organic yields ~0.2% for modern and ~0.06% for fossil Strombus spp. Future applications of this work include using this refined method to reconstruct food webs across broad temporal scales.
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Bushell, Alexandra. "Mixed matrix membranes of a polymer of intrinsic microporosity with crystalline porous solids." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/mixed-matrix-membranes-of-a-polymer-of-intrinsic-microporosity-with-crystalline-porous-solids(6166d350-d969-49bc-8108-1c9afcaaa2f9).html.
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This work explores the fabrication and permeability testing of mixed matrix membranes (MMM) utilising a polymer of intrinsic microporosity (PIM-1) and various fillers. PIM-1 has been chosen for this work due to its high apparent surface area and high sorption of gases. PIM-1 also is a good candidate for gas sorption applications due to the film forming properties of the polymer. The fillers utilised in this work are Metal Organic Frameworks (MOFs) and organic cages, which have been chosen due to the gas sorption properties they exhibit. The MOFs used are micro and nanoparticles of Zeolitic Imidazole Framework-8 (ZIF-8), copper based MOF HKUST-1 and chromium based MOF MIL-101. Micro particles of magnesium based MOF Mg-MOF-74 were also looked at as well as cage 3, nano cage 3 and reduced cage 3. Comparable surface areas of the MOFs compared to those quoted in the literature have been obtained. Successful PIM-1/Filler MMMs were synthesised utilising PIM-1 and the fillers outlined above with various loadings of filler. The highest loading achieved was with a 10:6.4 PIM-1/nanoZIF-8 ratio. All MMMs apart from PIM-1/Mg-MOF-74 MMM were homogenous on a macroscale with scanning electron microscopy proving the dispersion of fillers. Gas transport properties of the MMMs were determined using predominantly a time lag method. PIM-1/ZIF-8 MMMs were also tested using a chromatographic method and using a gas sorption experiment. A range of gases were tested including CO2, N2, CH4, O2, He and H2. Ideal selectivities were also calculated with focus on the gas pairs O2/N2, CO2/CH4 and CO2/N2.When comparing the two permeability methods using the PIM-1/nanoZIF-8 MMM, lower permeability results were found from the time lag method. This was concluded to be due to the aging effect brought about by the vacuum used in the time lag method. The chromatographic method produced positive results with high selectivities, breaking Robeson’s upper bound, for the gas pair O2/N2. All other fillers tested showed an increase in permeability and stable selectivity with an increase in the amount of filler. MIL-101 and Cage 3 were the most successful fillers with high permeabilities of 35600 and 37400 Barrer respectively, encroaching on that of PTMSP. Mg-MOF-74 and reduced cage 3 MMM however, had a detrimental effect on the permeability. Aging data was also investigated which showed that for the majority of MMM the permeability followed the trend of PIM-1. microHKUST-1 and cage 3 of 10:3 loading were shown to give promising results with 10000 and 14300 Barrer respectively compared to 7200 Barrer for PIM-1. Although a loss in permeability is seen, it is still above that of PIM-1 at the same point of aging. These results give a positive indication that MMMs have the potential to provide resistance against aging, a major problem in using high free volume polymers in industrial applications.
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Valle, Brent. "Design of Multilayer Optical Media: Organic Photovoltaics and Optical Data Storage." Case Western Reserve University School of Graduate Studies / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1364917393.
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Galvis, Leonardo [Verfasser], and Claudia [Akademischer Betreuer] Fleck. "Raman spectroscopy investigation of organic matrix orientation and chemistry changes during fracture healing / Leonardo Galvis. Betreuer: Claudia Fleck." Berlin : Universitätsbibliothek der Technischen Universität Berlin, 2012. http://d-nb.info/1023762293/34.
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Linck, Nicholas W. "MIXED MATRIX FLAT SHEET AND HOLLOW FIBER MEMBRANES FOR GAS SEPARATION APPLICATIONS." UKnowledge, 2018. https://uknowledge.uky.edu/cme_etds/89.
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Mixed matrix membranes (MMM) offer one potential path toward exceeding the Robeson upper bound of selectivity versus permeability for gas separation performance while maintaining the benefits of solution processing. Many inorganic materials, such as zeolites, metal-organic frameworks, or carbon nanotubes, can function as molecular sieves, but as stand-alone membranes are brittle and difficult to manufacture. Incorporating them into a more robust polymeric membrane matrix has the potential to mitigate this issue.
In this work, phase inversion polymer solution processing for the fabrication and testing of asymmetric flat sheet mixed matrix membranes was employed with CVD-derived multiwall carbon nanotubes (MWCNTs) dispersed in a polyethersulfone (PES) matrix. The effect of MWCNT loading on membrane separation performance was examined. Notably, a distinct enhancement in selectivity was measured for several gas pairs (including O2/N2) at relatively low MWCNT loading, with a peak in selectivity observed at 0.1 wt% loading relative to PES. In addition, no post-treatment (e.g. PDMS caulking) was required to achieve selectivity in these membranes. In contrast, neat PES membranes and those containing greater than 0.5 wt.% MWCNT showed gas selectivity characteristic of Knudsen diffusion through pinhole defects. These results suggested that at low loading, the presence of MWCNTs suppressed the formation of surface defects in the selective layer in flat sheet mixed matrix membranes.
Additionally, a bench-scale, single-filament hollow fiber membrane spinning line was designed and purpose-built at the University of Kentucky Center for Applied Energy Research (CAER). Hollow fiber membrane spinning capability was developed using polyethersulfone (PES) solution dopes, and the process was expanded to include polysulfone (PSf) as well as mixed matrix membranes. The effects of key processing parameters, including the ratio of bore to dope velocities, the spinning air gap length, and the draw-down ratio, were systematically investigated. Finally, direct hollow fiber analogues to flat sheet mixed matrix membranes were characterized. Consistent with the flat sheet experiments, the mixed matrix hollow fiber membranes showed a local maximum in selectivity at a nominal loading of 0.1 wt.% MWCNT relative to the polymer, suggesting that the pinhole suppression effect introduced by MWCNTs was not limited to flat sheet membrane casting.
The development of asymmetric hollow fiber mixed matrix membrane processing and testing capability at the UK Center for Applied Energy Research provides a platform for the further development of gas separation membranes. Using the tools developed through this work, it is possible to further push the frontiers of mixed matrix gas separation by expanding the capability to include more polymers, inorganic fillers, and post treatment processes which previously have been focused primarily on the flat sheet membrane geometry.
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Hoops, Michael Dean. "Matrix Isolation Studies of Photochemical and Thermal Reactions of Cyclic Organic Substrates with Chromyl Chloride and Ozone/O Atoms." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1211558149.
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Levichkova, Marieta. "Influence of the Matrix Environment on the Optical Properties of Incorporated Dye Molecules." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2008. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1205766500301-30732.
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The present thesis is concerned with solid solutions of organic dyes. The organic molecules are incorporated in both optically inert or active and in rigid or flexible matrices, respectively. Exclusively thin films prepared by physical vapor deposition are studied. The optical response of the systems, in dependence on their structure and on the matrix nature, is investigated by means of absorption and luminescence spectroscopy. In the first part, perylene and 2,2-difluoro-1,3,2-dioxaborine derivatives, and Alq3 (tris(8-hydroxyquinoline) aluminium) embedded in the optically inactive SiO2 and polyimide hosts are studied. For the system dye molecules/SiO2 matrix, two sample preparation approaches, co-deposition and layer-by-layer, are compared. It is demonstrated that the luminescence properties of the mixed layers are affected by dye distribution and thin film composition. The photoluminescence quantum efficiency is strongly influenced by dye aggregation and Föster transfer. Therefore, effective separation and isolation of dye molecules in the matrix results in increased PL efficiency. Furthermore, it is established that layer-by-layer growth mode assures more homogeneous dye distribution. The spectroscopic studies also show that, since dye and matrix condense successively in time, luminescence losses due to thermal degradation of molecules are reduced. Hence, the film structure can be optimized with regard to high absorption and luminescence quantum efficiency. The experimental findings suggest that the luminescent properties of the embedded dyes are influenced by the nature of the host environment as well. In the rigid SiO2 matrix, it is possible to observe isolated facial Alq3 molecules with distinctive blue luminescence. In contrast, in the "soft" organic polyimide matrix Alq3 exhibits ordinary green luminescence. Thus, the structural properties of the host, rigidity and density, are found to be crucial for preservation of the facial Alq3 molecules. It is further demonstrated that the immobilization of molecules in the rigid SiO2 matrix in combination with layer-by-layer growth results in improved photostability. In polyimide matrix, the behavior of incorporated molecules is governed by the morphological changes of the host. These changes are defined by the curing procedure, needed for imidization, and give rise to a certain film structure. In the second part, special attention is paid on the luminescence response of dispersed DCM (4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyril)-4H-pyran) and rubrene (5,6,11,12-tetraphenyl-naphthacene) molecules in the optically active Alq3 matrix. The observed enhancement of luminescence intensity and alteration of emitted color are favorable for application of the doped Alq3 films as converter layers in combination with commercial blue light emitting diodes in luminescence conversion devices. It is demonstrated that by optimization of the conversion layer parameters white light generation can be achieved. The devices are characterized by high conversion efficiency and Lambertian distribution of the emitted light. However, they lack sufficient stability with regard to practical applications.
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Gawlitza, Kornelia [Verfasser], and Regine von [Akademischer Betreuer] Klitzing. "P-NIPAM microgels as stimuli responsive matrix for embedding functional inorganic and organic particles / Kornelia Gawlitza. Betreuer: Regine von Klitzing." Berlin : Universitätsbibliothek der Technischen Universität Berlin, 2012. http://d-nb.info/1029355584/34.
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Tessema, Tsemre. "PREPARATION AND EVALUATION TECHNIQUES OF POROUS MATERIALS AND MIXED MATRIX MEMBRANES FOR TARGETED CO2 SEPARATION APPLICATIONS." VCU Scholars Compass, 2017. http://scholarscompass.vcu.edu/etd/5044.
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The use of porous sorbents for physisorptive capture of CO2 from gas mixtures has been deemed attractive due to the low energy penalty associated with recycling of such materials. Porous organic polymers (POPs) have emerged as promising candidates with potential in the treatment of pre- and post- fuel combustion processes to separate CO2 from gas mixtures. Concurrently, significant advances have been made in establishing calculation methods that evaluate the practicality of porous sorbents for targeted gas separation applications. However, these methods rely on single gas adsorption isotherms without accounting for the dynamic gas mixtures encountered in real-life applications. To this end, the design and application of a dynamic gas mixture breakthrough apparatus to assess the CO2 separation performance of a new class of heteroatom (N and O) doped porous carbons derived from a Pyrazole precursor from flue gas mixtures is presented.
Here in, two new benzimidazole linked polymers (BILPs) have been designed and synthesized. These polymers display high surface while their imidazole functionality and microporous nature resulted in high CO2 uptakes and isosteric heat of adsorption (Qst). BILP-30 displayed very good selectivity for CO2 in flue gas while BILP-31 was superior in CO2 separation from landfill gas mixtures at 298 K and 1 bar. Additionally, a new POP incorporating a highly conjugated pyrene core into a polymer framework linked by azo-bonds is presented. Azo-Py displays a nanofibrous morphology induced by the π-π stacking of the electron rich pyrene core. Due to its high surface area and microporous nature, Azo-Py displays impressive CO2 uptakes at 298 K and 1 bar. Evaluation of the S value for CO2 separation of Azo-Py revealed competitive values for flue gas and landfill gas at 298 K and 1 bar.
Finally, a highly cross-linked benzimidazole linked polymer, BILP-4, was successfully incorporated into Matrimid® polymer to form a series of new mixed matrix membranes. The surface functionality of BILP-4 was exploited to enhance the interaction with Matrimid® polymer matrix to produce robust MMMs which displayed significantly improved CO2 gas permeabilities and ideal selectivities for CO2/N2.
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Thenna, Hewa Kosala R. S. "Applications Focused Synthetic Modification on Photoremovable Protecting Groups (PRPG) & Photochemical Analysis on Organic Azides and Isoxazoles." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1511858669354976.
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Levichkova, Marieta. "Influence of the Matrix Environment on the Optical Properties of Incorporated Dye Molecules." Doctoral thesis, Technische Universität Dresden, 2007. https://tud.qucosa.de/id/qucosa%3A24056.
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The present thesis is concerned with solid solutions of organic dyes. The organic molecules are incorporated in both optically inert or active and in rigid or flexible matrices, respectively. Exclusively thin films prepared by physical vapor deposition are studied. The optical response of the systems, in dependence on their structure and on the matrix nature, is investigated by means of absorption and luminescence spectroscopy. In the first part, perylene and 2,2-difluoro-1,3,2-dioxaborine derivatives, and Alq3 (tris(8-hydroxyquinoline) aluminium) embedded in the optically inactive SiO2 and polyimide hosts are studied. For the system dye molecules/SiO2 matrix, two sample preparation approaches, co-deposition and layer-by-layer, are compared. It is demonstrated that the luminescence properties of the mixed layers are affected by dye distribution and thin film composition. The photoluminescence quantum efficiency is strongly influenced by dye aggregation and Föster transfer. Therefore, effective separation and isolation of dye molecules in the matrix results in increased PL efficiency. Furthermore, it is established that layer-by-layer growth mode assures more homogeneous dye distribution. The spectroscopic studies also show that, since dye and matrix condense successively in time, luminescence losses due to thermal degradation of molecules are reduced. Hence, the film structure can be optimized with regard to high absorption and luminescence quantum efficiency. The experimental findings suggest that the luminescent properties of the embedded dyes are influenced by the nature of the host environment as well. In the rigid SiO2 matrix, it is possible to observe isolated facial Alq3 molecules with distinctive blue luminescence. In contrast, in the "soft" organic polyimide matrix Alq3 exhibits ordinary green luminescence. Thus, the structural properties of the host, rigidity and density, are found to be crucial for preservation of the facial Alq3 molecules. It is further demonstrated that the immobilization of molecules in the rigid SiO2 matrix in combination with layer-by-layer growth results in improved photostability. In polyimide matrix, the behavior of incorporated molecules is governed by the morphological changes of the host. These changes are defined by the curing procedure, needed for imidization, and give rise to a certain film structure. In the second part, special attention is paid on the luminescence response of dispersed DCM (4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyril)-4H-pyran) and rubrene (5,6,11,12-tetraphenyl-naphthacene) molecules in the optically active Alq3 matrix. The observed enhancement of luminescence intensity and alteration of emitted color are favorable for application of the doped Alq3 films as converter layers in combination with commercial blue light emitting diodes in luminescence conversion devices. It is demonstrated that by optimization of the conversion layer parameters white light generation can be achieved. The devices are characterized by high conversion efficiency and Lambertian distribution of the emitted light. However, they lack sufficient stability with regard to practical applications.
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Gonçalves, Flavia. "Fatores relacionados ao desenvolvimento de tensões de polimerização em compósitos experimentais contendo BisGMA, TEGDMA e BisEMA." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/23/23140/tde-13082007-154602/.
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Objetivo: avaliar a influência do conteúdo de BisGMA, TEGDMA e BisEMA sobre tensão de polimerização (spol), grau de conversão (GC), contração volumétrica (CV), módulo de elasticidade (E), escoamento (ES), taxa máxima de reação (RPmax) e incremento máximo de tensão (RSmax) e verificar as possíveis relações de dependência entre a tensão de polimerização e as demais variáveis. Material e métodos: Foram estudadas nove misturas, todas contendo 40% em peso de sílica coloidal, variando a concentração molar de BisGMA (33, 50 ou 66%) e o tipo de comonômero (TEGDMA, BisEMA ou ambos em partes iguais). spol foi determinada pela inserção do compósito (h=1mm) entre bastões de acrílico (r=3mm) fixados às garras de uma máquina universal de ensaios e dividindo-se a máxima força de contração registrada pela secção transversal dos bastões. CV foi mensurada em dilatômetro de mercúrio. E foi obtido através do teste de flexão em três pontos. Fragmentos de espécimes de flexão de cada grupo foram utilizados para análise do GC por FTRaman. O ES foi obtido pela aplicação de uma carga de 20N por 60s sobre o compósito não-polimerizado. RPmax foi determinada por calorimetria exploratória diferencial (DSC). RSmax foi calculado pela diferença entre dois valores de spol consecutivos. Os dados foram submetidos a ANOVA de dois fatores, teste de Tukey (a=0,05%) e análises de regressão. Resultados: A interação entre os fatores foi estatisticamente significante para todas as variáveis avaliadas (p<0,01), com exceção de GC onde apenas os fatores principais foram significantes (p<0,001). Em geral, composições com maior concentração de BisGMA e com o co-monômero BisEMA apresentaram menor GC e ES, o que se refletiu em menores valores para spol, CV e E. RPmax foi semelhante em todos os grupos, com exceção do compósito com 66%TEGDMA, que apresentou valor estatisticamente menor. Entretanto,. esse grupo apresentou o maior valor de RSmax. As análises de regressão evidenciaram forte relação direta de dependência da spol com GC (R2=0,830), ES (R2=0,896), CV (R2=0,690) e RSmax (R2=0,900). A correlação com o E foi fraca (R2=0,404) e com RPmax foi negativa (R2=0,667). Conclusões: Dentre as formulações avaliadas, compósitos contendo BisEMA e aqueles com maiores concentrações de BisGMA apresentaram, em geral, menor spol, GC, CV, ES e E. RPmax foi pouco afetada pela composição da matriz orgânica. spol mostrou maior relação de dependência com os fatores GC, CV e ES.Objective: To evaluate the influence of BisGMA, TEGDMA and TEGDMA content on polymerization stress (spol), degree of conversion (DC), volumetric shrinkage (VS), elastic modulus (E), flow, maximum polymerization rate (RPmax) and maximum stress rate (RSmax) and to establish the correlation between polymerization stress and the other variables. Materials and Methods: Nine resin mixtures were studied, varying the BisGMA molar concentration (33, 50 or 66%) and the co-monomer content (TEGDMA, BisEMA or both in equal parts). All blends received 40 wt % of colloidal silica. spol was determined by inserting the composite (h=1mm) between acrylic rods (r=3mm) fixed on the opposite ends of a universal testing machine, and dividing the maximum contraction force by the rods? cross section. VS was measured by mercury dilatometry. E was obtained by three-point bending test. Fragments of flexural specimens were used to analyze DC by FT-Raman. Flow was obtained applying load of 20N for 60s on the uncured composite. RPmax was determined by differential scanning calorimetry (DSC). RSmax was calculated by the difference between two consecutives spol values. Data were submitted to two-way ANOVA, Tukey´s test (a=0.05%) and regression analyses. Results: The interactions between factors were significant for all variables (p<0.01), except for DC, where only the main factors were significant (p<0.001). In general, composites with higher BisGMA concentration and those containing BisEMA showed lower DC and flow, which resulted in lower values of spol, VS and E. RPmax was similar for all groups, except for the 66%TEGDMA composite, which showed a statistically lower value. However, this group showed the highest value of RSmax. The regression analyses evidenced a strong direct dependence of spol to DC (R2=0.830), flow (R2=0.896), VS (R2=0.690) and RSmax (R2=0.900). The correlation with E was weak (R2=0.404) and with RPmax was negative (R2=0.667). Conclusion: For the monomer mixtures studied, composites with BisEMA and those with higher BisGMA concentration showed, in general, lower spol, DC, VS, flow and E. RPmax was almost insensitive to the organic matrix composition. spol showed stronger dependence with DC, VS and flow.
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Andersson, Peter. "Charge Transport Modulation and Optical Absorption Switching in Organic Electronic Devices." Doctoral thesis, Norrköping : Department of Science and Technology, Linköping University, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-10271.
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Srivastava, Deepchandra. "Improving the discrimination of primary and secondary sources of organic aerosol : use of molecular markers and different approaches." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0055/document.
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Les aérosols organiques (AO), issus de nombreuses sources et de différents processus atmosphériques, ont un impact significatif sur la qualité de l’air et le changement climatique. L’objectif de ce travail de thèse était d’acquérir une meilleure connaissance de l’origine des AO par l’utilisation de marqueurs organiques moléculaires au sein de modèles source-récepteur de type positive matrix factorization (PMF). Ce travail expérimental était basé sur deux campagnes de prélèvements réalisées à Grenoble (site urbain) au cours de l’année 2013 et dans la région parisienne (site péri-urbain du SIRTA, 25 km au sud-ouest de Paris) lors d’un intense épisode de pollution aux particules (PM) en Mars 2015. Une caractérisation chimique étendue (de 139 à 216 espèces quantifiées) a été réalisée et l’utilisation de marqueurs moléculaires primaires et secondaires clés dans la PMF a permis de déconvoluer de 9 à 11 sources différentes de PM10 (Grenoble et SIRTA, de façon respective) incluant aussi bien des sources classiques (combustion de biomasse, trafic, poussières, sels de mer, nitrate et espèces inorganiques secondaires) que des sources non communément résolues telles que AO biogéniques primaires (spores fongiques et débris de plantes), AO secondaires (AOS) biogéniques (marin, oxydation de l’isoprène) et AOS anthropiques (oxydation des hydrocarbures aromatiques polycycliques (HAP) et/ou des composés phénoliques). En outre, le jeu de données obtenu pour la région parisienne à partir de prélèvements sur des pas de temps courts (4h) a permis d’obtenir une meilleure compréhension des profils diurnes et des processus chimiques impliquées. Ces résultats ont été comparés à ceux issus d’autres techniques de mesures (en temps réel, ACSM (aerosol chemical speciation monitor) et analyse AMS (aerosol mass spectrometer) en différée) et/ou d’autres méthodes de traitement de données (méthodes traceur EC (elemental carbon) et traceur AOS). Un bon accord a été obtenu entre toutes les méthodes en termes de séparation des fractions primaires et secondaires. Cependant, et quelle que soit l’approche utilisée, la moitié de la masse d’AOS n’était toujours pas complètement décrite. Ainsi, une nouvelle approche d’étude des sources de l’AO a été développée en combinant les mesures en temps réel (ACSM) et celles sur filtres (marqueurs moléculaires organiques) et en utilisant un script de synchronisation des données. L’analyse PMF combinée a été réalisée sur la matrice de données unifiée. 10 facteurs AO, incluant 4 profils chimiques différents en lien avec la combustion de biomasse, ont été mis en évidence. Par rapport aux approches conventionnelles, cette nouvelle méthodologie a permis d’obtenir une meilleure compréhension des processus atmosphériques liés aux différentes sources d’AOOrganic aerosols (OAs), originating from a wide variety of sources and atmospheric processes, have strong impacts on air quality and climate change. The present PhD thesis aimed to get a better understanding of OA origins using specific organic molecular markers together with their input into source-receptor model such as positive matrix factorization (PMF). This experimental work was based on two field campaigns, conducted in Grenoble (urban site) over the 2013 year and in the Paris region (suburban site of SIRTA, 25 km southwest of Paris) during an intense PM pollution event in March 2015. Following an extended chemical characterization (from 139 to 216 species quantified), the use of key primary and secondary organic molecular markers within the standard filter-based PMF model allowed to deconvolve 9 and 11 PM10 sources (Grenoble and SIRTA, respectively). These included common ones (biomass burning, traffic, dust, sea salt, secondary inorganics and nitrate), as well as uncommon resolved sources such as primary biogenic OA (fungal spores and plant debris), biogenic secondary AO (SOA) (marine, isoprene oxidation) and anthropogenic SOA (polycyclic aromatic hydrocarbons (PAHs) and/or phenolic compounds oxidation). In addition, high time-resolution filter dataset (4h-timebase) available for the Paris region also illustrated a better understanding of the diurnal profiles and the involved chemical processes. These results could be compared to outputs from other measurement techniques (online ACSM (aerosol chemical speciation monitor), offline AMS (aerosol mass spectrometer) analyses), and/or to other data treatment methodologies (EC (elemental carbon) tracer method and SOA tracer method). A good agreement was obtained between all the methods in terms of separation between primary and secondary OA fractions. Nevertheless, and whatever the method used, still about half of the SOA mass was not fully described. Therefore, a novel OA source apportionment approach has finally been developed by combining online (ACSM) and offline (organic molecular markers) measurements and using a time synchronization script. This combined PMF analysis was performed on the unified matrix. It revealed 10 OA factors, including 4 different biomass burning-related chemical profiles. Compared to conventional approaches, this new methodology provided a more comprehensive description of the atmospheric processes related to the different OA sources
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Streiter, Martin. "Chromophore-Matrix Interaction in Organic Semiconductors." 2020. https://monarch.qucosa.de/id/qucosa%3A71581.
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Organische Halbleiter sind Moleküle und Polymere, welche durch die Konjugation ihres Elektronensystems Eigenschaften erhalten, die klassischen anorganischen Halbleitern ähnlich sind. Dadurch eignen sie sich zur Anwendung in Solarzellen, Leuchtdioden, Farbstoffen und Photokatalysatoren. Im Gegensatz zu anorganischen Halbleitern bilden organische Halbleiter in dünnen Filmen meist ungeordnete Strukturen. Diese räumliche und energetische Unordnung ist auf molekulare Eigenschaften zurückzuführen und erschwert das Verständnis der Wirkungsweise von Bauteilen, wie beispielsweise organischen Solarzellen. Ursache ist, dass sich die photophysikalischen Eigenschaften einzelner organischer Halbleitermoleküle deutlich von ungeordneten Filmen unterscheiden. Der für die Wechselwirkung mit Licht entscheidende Bestandteil eines solchen Moleküls bzw. Monomers wird als Chromophor (griechisch Farbträger) bezeichnet. Die Interaktion von Chromophoren mit der umgebenden Matrix aus gleichen oder anderen Molekülen ist von zentraler Bedeutung für das Verständnis organischer Halbleiter und damit der Verbesserung von Bauteilen aus diesen Materialien. In der vorliegenden Arbeit werden neue experimentelle und mathematische Verfahren zur Analyse und Interpretation der photophysikalischen Eigenschaften von Chromophoren in Filmen organischer Halbleiter entwickelt und auf verschiedene Materialsysteme angewandt.
Die wesentlichen Erkenntnisse und Leistungen dieser Arbeit sind der erstmalige Nachweis der Zeitabhängigkeit der Stokes-Verschiebung (Differenz von Emission und Absorption eines Farbstoffs), die empirische Herleitung eines Chromophormodells zur Beschreibung von Exzitonendiffusion in Polymeren, die molekülbezogene Modellierung verzögerter Fluoreszenz sowie die ortsaufgelöste Emissions- und Absorptionsmessung eines Ladungstransferzustandes.
Die experimentellen Ergebnisse, entwickelten Methoden und hergeleiteten Modelle sind im Forschungsgebiet der organischen Halbleiter für verschiedene Teildisziplinen (Einzelmolekülspektroskopie, Solarzellen, Leuchtdioden, Photokatalyse) bedeutsam. Die Arbeit beschreibt damit themenübergreifend den Zusammenhang zwischen photophysikalischen Eigenschaften organischer Halbleiter und ihrer Ursache in den molekularen und energetischen Gegebenheiten einzelner Chromophore.
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Vieira, André Alves. "Erbium laser efects on the dentin organic matrix." Dissertação, 2020. https://hdl.handle.net/10216/127967.
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Vieira, André Alves. "Erbium laser efects on the dentin organic matrix." Master's thesis, 2020. https://hdl.handle.net/10216/127967.
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Wang, Mei-sheue, and 王美雪. "Modeling the Transport of Organic Compounds in Heterogeneous Soil Matrix." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/78772989560978276920.
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博士臺灣大學
環境工程學研究所
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ABSTRACT Heterogeneous unsaturated soil layers comprise both mobile and immobile regions as characterized by different flow velocities of fluid. The movement of pollutants is governed by advection and dispersion in mobile regions, and by diffusive mass transfer between mobile and immobile regions. In this study, the aim is to estimate the distribution of the first-order exchange rate coefficients that reveals the presence of soil-matrix heterogeneity, and to develop an advection-diffusion mass transport model that includes the distributed first-order exchange coefficients in unsaturated soils. The study also simulate the experimental results from laboratory soil columns and a soil-vapor-extraction (SVE) field site by using different organic compounds as tracers and under different test conditions. Modeling analyses and experimental results indicate that the including a log-normal distributed or a gamma distributed first-order exchange rate coefficient could explain the organic compounds transport in the vadose zone. Experimental results and model simulation could explain that the tailing phenomenon in chemical breakthrough curves, which signifies a non-equilibrium transport, resulting mainly from a rate-limiting exchange into and out of immobile (stagnant) regions. Model simulation could also explain the rebounding phenomenon and fit the data well by only adjusting the volume fraction of the immobile regions, the averaged radius of the aggregates and the standard deviation of the logarithmic first-order exchange rate coefficient. The problem of the lack of local geological information while modeling chemical transfer in immobile regions can be solved by using a set of first-order exchange rate coefficients in log-normal or gamma distribution, in which the related parameters are functions of the system length scale, the soil moisture content, and the chemical partition coefficient. Among these properties the system length scale is found the most important site-specific property. The findings from this study enable one to better predict the transport of trace pollutants in a heterogeneous vadose zone based on the properties of chemicals and the soil system. The model will be able to predict the organic compounds moving and distribution situation in soil and groundwater. Also the model will be able to assist the designing of the SVE system and operational strategy, and the prediction of the performance of the clean-up actions.