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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.
11

Synthèse de phase stationnaires monolithiques de silice hybrides pour les techniques séparatives miniaturisées / Synthesis of hybrid silica monolithic supports for applications to miniaturized chromatographic separations

Roux, Richard 27 November 2009 (has links)
Ce manuscrit est consacré à la synthèse par procédé sol-gel et à la caractérisation de matériaux monolithiques de silice hybrides pour les techniques séparatives miniaturisées : nano-chromatographie en phase liquide (nano-CPL), électrochromatographie capillaire (ECC) et microsystèmes séparatifs. La partie bibliographique situe les axes de développement récents des techniques séparatives : l’augmentation de l’efficacité par unité de temps, l’augmentation de la capacité de pics et la miniaturisation de ces techniques. Après un descriptif détaillé de l’évolution des techniques séparatives lors de ces dernières années, une attention particulière est portée sur les phases stationnaires monolithiques à base de silice. Enfin, une étude approfondie des différentes fonctionnalisations de ces monolithes de silice met en évidence l’intérêt porté aux monolithes de silice hybrides en termes de simplification du protocole de synthèse. La partie expérimentale est ainsi axée sur le développement et la caractérisation de ces monolithes de silice hybrides dédiés à la chromatographie à polarités de phases inversée. Dans un premier temps, la synthèse de monolithes de silice hybrides C3 illustre la possibilité de synthétiser par voie sol-gel (100% aqueux) un monolithe de silice fonctionnalisé et performant en une seule étape (« one pot »). Dans un second temps, ce type de procédé est employé et optimisé afin de synthétiser des capillaires monolithiques de silice hybrides C8 présentant des performances équivalentes à leurs homologues C8 préparés en deux étapes (synthèse puis greffage) et comparables à des colonnes particulaires (d particules 5 μm) / This manuscript is dedicated to the synthesis (via sol-gel process) and caracterization of hybrid monolithic silica for miniaturized separation techniques : nano-liquid chromatography (nano-LC), capillary electrochromatography (CEC) and microchips. The bibliography part deals with the recent axis of development of these separatives techniques : increase of efficiency per time unit, increase of peak capacity and miniaturisation of these techniques. After an overview of this evolution, the manuscript is focused on the silica monolithic stationnary phases. Finally, a detailed study on the different kinds of protocol fonctionnalization of these silica monoliths highlights the advantage of simplifying the synthesis using a single step protocol (« one pot »). The experimental part is also focused on this kind of single step protocol so as to synthesize hybrid silica monoliths dedicated to the reversed phase mode in chromatography. First, the synthesis of hybrid C3 silica monoliths shows the ability to synthesize a functionnalized silica monolith via a single step sol gel process (« one pot »). Then, this kind of process is used and optimized in order to synthesize a hybrid C8 silica monolithic into capillaries. These stationary phases allowed reaching performances similar to those synthesized in two steps (sol-gel process and grafting) and to the particulate columns (5 μm).
12

Développement d’un laboratoire sur puce pour la préconcentration sur support monolithique. Application à l'enrichissement et la séparation en ligne de phosphopeptides. / Development of a lab on-a-chip for monolith-based preconcentration and separation of phosphopeptides

Araya-Farias, Monica 22 March 2016 (has links)
Les laboratoires sur puce sont des dispositifs miniaturisés qui offrent la possibilité d'intégrer en ligne toutes les étapes de la chaîne analytique tout en réduisant les volumes d’échantillon et les temps d’analyse. Ainsi, ils constituent potentiellement un outil de diagnostic particulièrement adapté pour l’analyse de biomarqueurs phosphorylés, pour lesquels une préconcentration est nécessaire en raison de leur faible abondance dans les fluides biologiques. C’est pourquoi, de nouvelles méthodes, dédiées à l'enrichissement de phosphopeptides, ont été développées ces dernières années et en particulier celles utilisant des supports solides basées sur la chromatographie d’affinité sur des ions métalliques immobilisés (IMAC). Parmi les supports solides intégrables en microsystème, les monolithes organiques constituent une option privilégiée grâce à la possibilité d’être synthétisés in situ. Le but de ce travail de thèse était donc de développer un laboratoire sur puce intégrant une préconcentration des phosphopeptides sur support monolithique basé sur le principe de l’IMAC et leur séparation électrophorétique en ligne.Dans un premier temps, nous avons développé deux approches innovantes qui ont permis de synthétiser pour la première fois un monolithe à base d’éthylène glycol méthacrylate phosphate (EGMP) et de bisacrylamide (BAA) par voie photochimique dans des microsystèmes. La première stratégie développée dans des puces en verre repose sur la synthèse du monolithe à l’aide d’un microscope à épifluorescence. La deuxième approche est basée sur les propriétés photochimiques d’un nouvel amorceur qui a permis de synthétiser et d’ancrer le monolithe, en une seule étape, aux parois des puces en polydiméthylsiloxane (PDMS). Une caractérisation de ce monolithe en termes de morphologie, de perméabilité, de porosité et de surface spécifique a ensuite été réalisée. Ceci a permis de démontrer le potentiel de ce monolithe pour la préconcentration.Dans un deuxième temps, une méthode de séparation par électrophorèse couplée à une détection par fluorescence a été développée sur puce en verre. Celle-ci a permis de séparer un mélange de phosphopeptides modèles fluorescents possédant différents sites et degrés de phosphorylation. Les phosphopeptides ont été détectés en moins de 2 min avec une excellente résolution (R>3) et une bonne efficacité (plateaux théoriques compris entre 11000 et 25000). Enfin, le couplage en ligne du module de préconcentration monolithique et de séparation/détection a été réalisé. Sur ce dispositif miniaturisé, une préconcentration basée sur l’IMAC-Zr4+ a ainsi été développée. L’efficacité de la capture et de l’élution des phosphopeptides a été démontrée et des facteurs de préconcentration supérieurs à 340 ont été obtenus. En conclusion, ce laboratoire sur puce ouvre des perspectives très prometteuses dans le domaine du diagnostic de pathologies dont le processus physiopathologique implique des phosphopeptides.Mots clés : laboratoire sur puce, microsystème, phosphopeptide, IMAC, monolithe, photopolymérisation, préconcentration, électrophorèse sur puce / A lab on-a-chip is a miniaturized device that integrates onto a single chip different analytical steps (preconcentration, separation, detection...) with minimal sample consumption and short analysis time. They are potentially beneficial in phosphorylated biomarker analysis for which a preconcentration step is necessary because of their low abundance in biological fluids. That's why selective enrichment methods of phosphopeptides have been developed in recent years in particular those based on solid supports like Immobilized Metal Affinity Chromatography (IMAC). Among the solid supports, organic polymer monoliths present practical advantages when used in microchips due to their ease of preparation and in situ polymerization. The aim of this work was to develop a lab-on-a-chip integrating a monolithic support for online IMAC-based preconcentration and electrophoretic separation of phosphopeptides.In the first part, we developed two innovative approaches which allowed us to synthesize, for the first time, an ethylene glycol methacrylate phosphate-co-bisacrylamide (poly (EGMP-co-BAA)) monolith by a photo-driven process in microsystems. The first monolith synthesis approach was developed in glass microchannels using an inverted epifluorescence microscope as UV-irradiation source. The second approach was based on the photochemical properties of a new initiator which allowed the simultaneous synthesis and anchorage of the monolith in native polydimethylsiloxane (PDMS) microchips. A characterization (morphology, permeability, porosity and specific surface area) of (poly (EGMP-co-BAA)) monolith was then performed which demonstrated the potential of this monolith for preconcentration.Then a glass microchip electrophoresis method coupled to a detection by fluorescence was developed to separate a mixture of phosphopeptides fluorescent models differing with the position and number of phosphorylation sites. The phosphopeptides were detected in less than 2 min with excellent resolution (R> 3) and good efficiencies ranging from 11000 to 25000 plates. Finally, an integrated microdevice was developed by combining online preconcentration based on IMAC-Zr4+ and separation/detection of phosphopeptides. The performance of this integrated microdevice to capture and to elute the phosphopeptides was demonstrated and signal enhancement factors (SEF) higher than 340 were obtained. This lab-on-a-chip device opens news perspectives for phosphoproteomic applications and the diagnostic of diseases where the pathophysiological process involves phosphopeptides
13

Efeito do tamanho do abrasivo no desgaste de metais. / The effect of abrasive size on the wear resistance of metallic materials.

Coronado Marin, John Jairo 08 June 2010 (has links)
Neste trabalho, foi investigado o efeito do tamanho do abrasivo na resistência ao desgaste de cinco ligas metálicas. Foi usado, para este estudo, o equipamento pino contra lixa e alumina como abrasivo, com tamanho médio entre 16 µm e 192 µm. A microestrutura das ligas metálicas foi caracterizada com microscopia ótica e os mecanismos de desgaste abrasivo e os microcavacos (partículas de desgaste) foram caracterizados usando microscopia eletrônica de varredura (MEV). Em uma primeira série de experimentos, foi usado ferro fundido mesclado com carbonetos M3C (temperado e revenido a temperaturas entre 300 e 600°C). Para abrasivos pequenos, a perda de massa elevou-se com o aumento do tamanho do abrasivo. Entretanto, para abrasivos grandes, a perda de massa aumenta com inclinação menor e o mecanismo prevalente de desgaste é o microcorte. Para abrasivos maiores, o mecanismo prevalente de desgaste é microsulcamento. Em uma segunda série de experimentos, foi usado ferro fundido branco (FFB), com matrizes austenítica e martensítica. O FFB com matriz austenítica apresentou um tamanho crítico de abrasivo (TCA) de 36 µm e, para o ferro fundido martensítico, foi aproximadamente de 116 µm. A perda de massa do ferro fundido com matriz austenítica aumentou linearmente com o aumento do tamanho dos abrasivos, após o TCA a perda de massa aumenta com inclinação menor. O FFB martensítico, com menores tamanhos do abrasivo, apresentou um comportamento linear. Existe, porém, uma região de transição não-linear e achatada, quando o tamanho de partícula crítico é atingido, tornando-se independente do tamanho do abrasivo. Antes do TCA, o micromecanismo prevalente de desgaste foi microcorte e a lixa apresentou cavacos contínuos e finos e, após o TCA, o mecanismo prevalente de desgaste foi microsulcamento e apresentou cavacos descontínuos e deformados. O efeito do tamanho de abrasivo observado na perda de massa foi apresentado na energia especifica de corte e no coeficiente de atrito. Em uma terceira série de experimentos, foi usado alumínio e aço AISI 1045. O alumínio (estrutura cristalina cúbica de fase centrada) apresentou um comportamento similar ao observado no FFB com matriz austenítica, e o aço AISI 1045 apresentou um comportamento similar ao FFB com matriz martensítica. Verificou-se que, no alumínio e no aço AISI 1045, também se apresenta mudança na morfologia dos cavacos e nos micromecanismos de desgaste, observados nos materiais com segunda fase dura. Em uma quarta série de experimentos, foi usado o ferro fundido cinzento para corroborar a mudança dos micromecanismos de desgaste abrasivo e dos microcavacos com o TCA. O ferro fundido cinzento não apresentou uma transição (TCA) na curva de tamanho de abrasivo contra perda de massa. A morfologia dos cavacos foi similar para os diferentes tamanhos de abrasivos (descontínua). Para abrasivos menores, porém, apresentaram-se alguns cavacos contínuos e finos. O micromecanismo prevalente de desgaste abrasivo foi de microcorte para os diferentes abrasivos usados. Portanto, nesta pesquisa, foi demonstrado que o tamanho crítico de abrasivo está relacionado com os micromecanismos de desgaste e com a morfologia dos microcavacos. / In this research, the effect of abrasive size on the wear resistance of five metallic materials was investigated. Abrasive wear tests using a pin test on alumina paper were carried out using abrasive sizes between 16 µm and 192 µm. The wear surface of the specimens was examined by scanning electron microscopy for identifying the wear micromechanism and the type of microchips formed on the abrasive paper (wear debris). In a first series of experiments mottled cast iron samples with M 3 C carbides were tested. The samples were quenched and tempered in temperatures ranging from 300°C to 600°C. For small abrasive particles, the wear mass loss increased linearly with the increase of particle size. However, for higher abrasive sizes the wear mass loss increased much more slowly. For lower abrasive sizes the main wear mechanism was microcutting. For higher abrasive sizes, the main wear mechanism was microploughing. In a second series of experiments white cast iron with M 3 C carbide with austenitic and martensitic matrix were tested. The results show that the mass loss for cast irons with austenitic and martensitic matrices increases linearly with the increase of particle size until the critical particle size is reached. The cast iron with austenitic matrix presented a critical abrasive size of 36 µm and for the martensitic cast iron, the critical particle size was about 116 µm. After the critical particle size is reached, the rate of mass loss of the cast iron with austenitic matrix diminishes to a lower linear rate, and for cast irons with martensitic matrix the curve of mass loss is non-linear and flattens when the critical particle size is reached. It becomes, then, constant, independent of additional size increases. The abrasive paper in contact with the iron of both austenitic and martensitic matrices presents fine continuous microchips and the main wear mechanism was microcutting before reaching critical particle size, and after that it presents deformed discontinuous microchips and the main wear mechanism was microploughing. This behavior of change in rates after reaching a critical size happened not only for mass loss versus abrasive size, but it was also observed both in curves of friction coefficient and specific cutting energy versus abrasive size. In a third series of experiments aluminum and AISI 1045 steel were tested. The first (FCC structure) showed similar behavior to that observed in the white cast iron with austenitic matrix and the latter showed similar behavior to that observed in white cast iron with martensitic matrix. Both aluminum and AISI 1045 steel show similar changes in the microchips morphology and in the wear micromechanisms, something that had been observed before in materials with hard second phase. In a fourth series of experiments gray cast iron was tested in order to demonstrate the relationship between the abrasive wear micromechanisms and the type of microchips, before and after achieving critical abrasive size. The grey cast iron did not show a transition in the curve of abrasive size against mass loss. The morphology of the chips was similar for the different sizes of abrasive (discontinuous). However, smaller abrasive sizes some thin continuous microchips were formed. The main abrasive wear micromechanism was microcutting for the different abrasives sizes tested. Therefore, it was shown that the critical abrasive size is related to the wear micromechanisms and the microchips morphology.
14

Efeito do tamanho do abrasivo no desgaste de metais. / The effect of abrasive size on the wear resistance of metallic materials.

John Jairo Coronado Marin 08 June 2010 (has links)
Neste trabalho, foi investigado o efeito do tamanho do abrasivo na resistência ao desgaste de cinco ligas metálicas. Foi usado, para este estudo, o equipamento pino contra lixa e alumina como abrasivo, com tamanho médio entre 16 µm e 192 µm. A microestrutura das ligas metálicas foi caracterizada com microscopia ótica e os mecanismos de desgaste abrasivo e os microcavacos (partículas de desgaste) foram caracterizados usando microscopia eletrônica de varredura (MEV). Em uma primeira série de experimentos, foi usado ferro fundido mesclado com carbonetos M3C (temperado e revenido a temperaturas entre 300 e 600°C). Para abrasivos pequenos, a perda de massa elevou-se com o aumento do tamanho do abrasivo. Entretanto, para abrasivos grandes, a perda de massa aumenta com inclinação menor e o mecanismo prevalente de desgaste é o microcorte. Para abrasivos maiores, o mecanismo prevalente de desgaste é microsulcamento. Em uma segunda série de experimentos, foi usado ferro fundido branco (FFB), com matrizes austenítica e martensítica. O FFB com matriz austenítica apresentou um tamanho crítico de abrasivo (TCA) de 36 µm e, para o ferro fundido martensítico, foi aproximadamente de 116 µm. A perda de massa do ferro fundido com matriz austenítica aumentou linearmente com o aumento do tamanho dos abrasivos, após o TCA a perda de massa aumenta com inclinação menor. O FFB martensítico, com menores tamanhos do abrasivo, apresentou um comportamento linear. Existe, porém, uma região de transição não-linear e achatada, quando o tamanho de partícula crítico é atingido, tornando-se independente do tamanho do abrasivo. Antes do TCA, o micromecanismo prevalente de desgaste foi microcorte e a lixa apresentou cavacos contínuos e finos e, após o TCA, o mecanismo prevalente de desgaste foi microsulcamento e apresentou cavacos descontínuos e deformados. O efeito do tamanho de abrasivo observado na perda de massa foi apresentado na energia especifica de corte e no coeficiente de atrito. Em uma terceira série de experimentos, foi usado alumínio e aço AISI 1045. O alumínio (estrutura cristalina cúbica de fase centrada) apresentou um comportamento similar ao observado no FFB com matriz austenítica, e o aço AISI 1045 apresentou um comportamento similar ao FFB com matriz martensítica. Verificou-se que, no alumínio e no aço AISI 1045, também se apresenta mudança na morfologia dos cavacos e nos micromecanismos de desgaste, observados nos materiais com segunda fase dura. Em uma quarta série de experimentos, foi usado o ferro fundido cinzento para corroborar a mudança dos micromecanismos de desgaste abrasivo e dos microcavacos com o TCA. O ferro fundido cinzento não apresentou uma transição (TCA) na curva de tamanho de abrasivo contra perda de massa. A morfologia dos cavacos foi similar para os diferentes tamanhos de abrasivos (descontínua). Para abrasivos menores, porém, apresentaram-se alguns cavacos contínuos e finos. O micromecanismo prevalente de desgaste abrasivo foi de microcorte para os diferentes abrasivos usados. Portanto, nesta pesquisa, foi demonstrado que o tamanho crítico de abrasivo está relacionado com os micromecanismos de desgaste e com a morfologia dos microcavacos. / In this research, the effect of abrasive size on the wear resistance of five metallic materials was investigated. Abrasive wear tests using a pin test on alumina paper were carried out using abrasive sizes between 16 µm and 192 µm. The wear surface of the specimens was examined by scanning electron microscopy for identifying the wear micromechanism and the type of microchips formed on the abrasive paper (wear debris). In a first series of experiments mottled cast iron samples with M 3 C carbides were tested. The samples were quenched and tempered in temperatures ranging from 300°C to 600°C. For small abrasive particles, the wear mass loss increased linearly with the increase of particle size. However, for higher abrasive sizes the wear mass loss increased much more slowly. For lower abrasive sizes the main wear mechanism was microcutting. For higher abrasive sizes, the main wear mechanism was microploughing. In a second series of experiments white cast iron with M 3 C carbide with austenitic and martensitic matrix were tested. The results show that the mass loss for cast irons with austenitic and martensitic matrices increases linearly with the increase of particle size until the critical particle size is reached. The cast iron with austenitic matrix presented a critical abrasive size of 36 µm and for the martensitic cast iron, the critical particle size was about 116 µm. After the critical particle size is reached, the rate of mass loss of the cast iron with austenitic matrix diminishes to a lower linear rate, and for cast irons with martensitic matrix the curve of mass loss is non-linear and flattens when the critical particle size is reached. It becomes, then, constant, independent of additional size increases. The abrasive paper in contact with the iron of both austenitic and martensitic matrices presents fine continuous microchips and the main wear mechanism was microcutting before reaching critical particle size, and after that it presents deformed discontinuous microchips and the main wear mechanism was microploughing. This behavior of change in rates after reaching a critical size happened not only for mass loss versus abrasive size, but it was also observed both in curves of friction coefficient and specific cutting energy versus abrasive size. In a third series of experiments aluminum and AISI 1045 steel were tested. The first (FCC structure) showed similar behavior to that observed in the white cast iron with austenitic matrix and the latter showed similar behavior to that observed in white cast iron with martensitic matrix. Both aluminum and AISI 1045 steel show similar changes in the microchips morphology and in the wear micromechanisms, something that had been observed before in materials with hard second phase. In a fourth series of experiments gray cast iron was tested in order to demonstrate the relationship between the abrasive wear micromechanisms and the type of microchips, before and after achieving critical abrasive size. The grey cast iron did not show a transition in the curve of abrasive size against mass loss. The morphology of the chips was similar for the different sizes of abrasive (discontinuous). However, smaller abrasive sizes some thin continuous microchips were formed. The main abrasive wear micromechanism was microcutting for the different abrasives sizes tested. Therefore, it was shown that the critical abrasive size is related to the wear micromechanisms and the microchips morphology.
15

Tunable Microchips for Imaging Protein Structures formed in Breast Cancer Cells

Alden, Nicholas Andrew 16 April 2018 (has links)
The breast cancer susceptibility protein, BRCA1, is a tumor suppressor that helps maintain genomic integrity. Changes in BRCA1 that effect DNA repair processes can fuel cancer induction. The Kelly lab, at the Virginia Tech Carilion Research Institute, has recently developed a new methodology that employs silicon nitride (SiN) microchips to isolate BRCA1 assemblies from the nuclear material of breast cancer cells. These microchips are coated with adaptor proteins that include antibodies against target proteins of interest. The adaptor proteins are added in sequential steps to the coated microchips, followed by an aliquot of sample containing the protein of interest, such as BRCA1. The Kelly lab, partnered with Protochips Inc., developed these devices as a robust, tunable platform to monitor molecular processes, and refer to them as 'Cryo-SiN' in cryo-Electron Microscopy (EM) imaging. We are currently using Cryo-SiN to recruit BRCA1 protein assemblies to the microchip surface under mild conditions, while simultaneously preparing them for cryogenic preservation and EM imaging. This strategy presents a viable alternative to antibody affinity columns that require stringent elution steps to obtain protein complexes from the column. Another advantage of the microchip strategy is that it requires only a 30-minute nuclear extraction, a 60-minute enrichment procedure, and a 5-minute microchip capture step--a total of 95 minutes from initially lysing the cells to plunge-freezing the EM specimens. Therefore, these novel approaches represent a major departure from classical separation procedures that often require days to complete, during which time active protein assemblies can readily dissociate or become inactive. Overall, our use of BRCA1-specific microchips may reveal changes in the BRCA1 architecture during various stages of cancer progression--a major gap in knowledge that persists in cancer research. / M. S. / Modern advances in the imaging technology used for cryogenic electron microscopy (cryo-EM) have offered researchers an extraordinary view into the world of biology at the nanoscale. Supplemental to these technical innovations is the development of tunable substrates based on functional new materials that revolutionize the sequestering of biological components from human cells, such as protein complexes formed in breast cancer cells. New developments of novel viewing substrates, given traditional electron microscopy viewing grids have remained unchanged for decades, is the logical next step into the future of enhanced cryo-EM imaging. Tunable microchip substrates, made using recently enhanced micro-engineering techniques, are currently under development for use in cryo-EM imaging. In this work I have examined these microchip substrates for their capacity to streamline the isolation of biomolecules such as the protein most prominently cited in breast cancer, known as the breast cancer susceptibility protein (BRCA1). Utilizing these novel microchip substrates in the Kelly Lab, I have collected and analyzed data containing BRCA1 proteins, formed in human breast cancer cells, toward the development of 3-dimensional protein structures that allow us to peer into the structure-function relationships of these proteins. New and exciting Cryo-EM data, collected using these newly developed microchips, has the potential to reveal obscure disease mechanisms being propagated at the molecular level in modern clinical practice, such as breast cancer.
16

Mise au point d'un microsystème électrophorétique pour l'analyse des hydrocarbures aromatiques polycycliques dans les huiles alimentaires / Development of a capillary electrophoresis microchip for polycyclic aromatic hydrocarbons analysis in edible oils

Ferey, Ludivine 31 October 2013 (has links)
Les hydrocarbures aromatiques polycycliques (HAP) sont des contaminants de notre environnement et de notre alimentation. En raison de leur toxicité, la Commission européenne a réglementé leur teneur dans les denrées alimentaires et notamment dans les huiles. Les industriels des corps gras ont donc pour obligation de vérifier la conformité de leurs produits. Dans ce contexte, le groupe Lesieur souhaiterait développer un nouvel outil analytique rapide et portable. Ainsi, ce vaste projet de recherche vise à concevoir un microsystème électrophorétique capable d'analyser les HAP dans les huiles alimentaires. Première étude à s'inscrire dans ce projet, ce travail de thèse a donc consisté à développer de nouveaux protocoles analytiques. Dans une première partie, des méthodes de séparation des HAP ont été développées en électrophorèse capillaire (CE) modifiée par des cyclodextrines couplée à un détecteur de fluorescence induite par laser. En suivant des stratégies multivariées basées sur les plans d'expériences, deux méthodes de séparation ont été optimisées. Les huit HAP communs aux listes établies par l'agence de protection de l'environnement des Etats-Unis et l'agence européenne de sécurité sanitaire des aliments ont été séparés en moins de 7 min et dix-neuf HAP, également classés par ces deux organismes, ont été analysés en moins de 18 min. Ces méthodes de séparation ont été appliquées avec succès à des extraits d'huile dopés. Dans une deuxième partie, il a été question de transférer la méthode d'analyse des huit HAP au format microsystèmes. La principale difficulté rencontrée a été le manque de sensibilité du système de détection couplé aux puces. Le premier objectif a donc été d'optimiser les quantités d'échantillon injectées et les paramètres de la détection avec un composé modèle dans un tampon borate. Cependant, seulement quatre HAP sur les dix-neuf étudiés précédemment en CE ont pu être détectés. Toutefois, dans les conditions optimisées par le plan d'expériences, ils étaient séparés en moins de 4 min. Enfin, différents polymères à empreintes moléculaires (MIP) ont été synthétisés en vue d'extraire sélectivement les HAP des huiles. Après un criblage des conditions de synthèse, la sélectivité de chaque MIP a été évaluée en milieu pur en comparant sa capacité de rétention avec celle d'un polymère non-imprimé. Les huit HAP communs aux deux listes ont finalement pu être extraits sélectivement à partir d'huiles de tournesol, mais avec des rendements d'extraction encore insuffisants et qui nécessitent une amélioration de la procédure d'extraction. / Polycyclic aromatic hydrocarbons (PAHs) are widespread contaminants in the environment and food products. Given their toxicity, their concentrations are regulated by the European Commission in food products and especially in edible oils. Consequently, manufacturers of fat products have to verify the conformity of their products. In this context, Lesieur wants to develop a rapid and portable new analytical tool. Hence, this ambitious research project aims at developing a capillary electrophoresis microchip for PAH analysis in edible oils. This PhD study, first one involved in this project, consisted in developing new analytical protocols.In a first part, PAH separation methods were developed by cyclodextrin-modified capillary electrophoresis (CE) with laser-induced fluorescence detection. Using experimental design-based strategies, two separation methods were optimized. The 8 PAHs in common between the United States Environmental Protection Agency and the European Food Safety Authority lists of priority pollutants were separated in less than 7 min, while 19 PAHs, also targeted by these institutions, were separated in less than 18 min. These CE separation methods were successfully applied to the analysis of spiked edible oil extracts.The second part aimed at transferring the electrophoretic separation method of the 8 PAHs from the capillary to the microsystem format. The lack of sensitivity of the detection system hyphenated with chips was the main difficulty encountered. Thus, injected sample amounts and detection parameters were first optimized with a model compound in a borate buffer. However, only 4 out of the 19 PAHs, previously studied in CE, could be detected. Nevertheless, under conditions predicted by the design of experiments, they were baseline resolved in less than 4 min.Finally, several molecularly imprinted polymers (MIPs) were synthesized for the selective extraction of PAHs from oils. After a screening of synthesis conditions, the selectivity of each MIP was evaluated in pure media by comparing the extraction recoveries obtained on MIP with those obtained on a non-imprinted polymer. Finally, the 8 PAHs in common between the two lists were selectively extracted from sunflower oils, but with low recoveries. Improvements in extraction procedures are still required.
17

Overcoming logistical problems in organizations : The case of Elicom AB

Khaki Boukani, Farzad January 2007 (has links)
This paper presents an empirical case study of the company Elicom AB. Elicom AB is producing electrical devices that are mostly used in the telecom market where the main customers are. The data that was collected from this case was collected through observations, interviews and the study of company documents. This allowed the author to compare secondary and primary data, as well as quantitative and qualitative information. The problem, the company is facing in the logistical field, was discovered in the labeling production process. The production of the labels is unnecessarily complicated and inefficient due to incompatibility of the computer systems. Therefore some parts of the label design have to be made manually, even though the company has a scanning system. When analyzing the problem in detail it became clear to the author that it could be fixed easily and fast and that the key individuals involved in the process already knew the answer to the problem. Therefore the question of the underlying cause of the problem arose. Why has the company not yet fixed the problem if it is so obvious and also everybody in the organization is aware of it? When further reanalyzing the problem, the author discovered a second problem, which was not lying in the logistics of the production process, but had its roots in the organizational structure. The problem of interfering authorities and responsibilities made it impossible for the company to overcome the changes needed to solve the logistical problem in the labeling production process. Therefore this problem must be addressed first, together with overcoming the obstacles to change in the organization, to make a problem-solving-process in the logistical area possible. In general this paper shows the interrelation of logistics with organization and the highly complex environment manufacturing companies are facing when it comes to changes in the production process. / Denna uppsats är en empirisk fallstudie som gjordes på Elicom AB. Elicom AB är en tillverkare av elektrisk apparatur som till mestadels används inom Telecom-marknaden, vilket också är den marknad som de flesta av företagets kunder finns inom. Den data som författaren samlat in är igenom observationer, intervjuer samt analys av olika interna företagsdokument. Detta gjorde att författaren kunde jämföra sekundär-och primär-data samt kvalitativ-och kvantitativ-data. Problemet som företaget hade framför sig var av logistisk karaktär och upptäcktes i etikettproduktionsprocessen. Produktionen av etiketter är onödigt komplicerad och ineffektiv pga icke kompatibla datasystem. Därför sker visa delar av skapandet av etiketter manuellt, även om företaget har ett scanning system. Efter viss analys blev det dock klart för författaren att problemet var lätt att ordna upp och att huvudpersonerna som var involverade, i etikett hanteringen, visste om att problemet var lätt löst men gjorde inget åt situationen. Detta ledde till att författaren fråga sig vad den underliggande orsaken, till detta problem, kunde vara. Varför har inte företaget gjort något åt problemet om det har varit uppenbart för dem att problemet existerar? När all information sedan om analyserades, upptäckte författaren ett andra problem vilket inte var inom logistikområdet utan hade sina rötter i organisationens struktur. Problemet med överlappande auktoritet, samt ansvarsområden, gör det omöjligt för företaget att lösa deras logistiska problem inom etiketthanteringen. Därför måste detta problem ses över först, samtidigt som inställningen till förändring måste ändras för att göra det möjligt att skapa en ”problem-lösnings-process” i den logistiska delen. Generellt visar denna fallstudie på relationen mellan logistik- och organisation och på den mycket komplicerade miljön som tillverkande företag ställs inför vid en förändring av sina processer.
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Overcoming logistical problems in organizations : The case of Elicom AB

Khaki Boukani, Farzad January 2007 (has links)
<p>This paper presents an empirical case study of the company Elicom AB. Elicom AB is producing electrical devices that are mostly used in the telecom market where the main customers are. The data that was collected from this case was collected through observations, interviews and the study of company documents. This allowed the author to compare secondary and primary data, as well as quantitative and qualitative information. The problem, the company is facing in the logistical field, was discovered in the labeling production process.</p><p>The production of the labels is unnecessarily complicated and inefficient due to incompatibility of the computer systems. Therefore some parts of the label design have to be made manually, even though the company has a scanning system. When analyzing the problem in detail it became clear to the author that it could be fixed easily and fast and that the key individuals involved in the process already knew the answer to the problem. Therefore the question of the underlying cause of the problem arose. Why has the company not yet fixed the problem if it is so obvious and also everybody in the organization is aware of it?</p><p>When further reanalyzing the problem, the author discovered a second problem, which was not lying in the logistics of the production process, but had its roots in the organizational structure. The problem of interfering authorities and responsibilities made it impossible for the company to overcome the changes needed to solve the logistical problem in the labeling production process. Therefore this problem must be addressed first, together with overcoming the obstacles to change in the organization, to make a problem-solving-process in the logistical area possible.</p><p>In general this paper shows the interrelation of logistics with organization and the highly complex environment manufacturing companies are facing when it comes to changes in the production process.</p> / <p>Denna uppsats är en empirisk fallstudie som gjordes på Elicom AB. Elicom AB är en tillverkare av elektrisk apparatur som till mestadels används inom Telecom-marknaden, vilket också är den marknad som de flesta av företagets kunder finns inom. Den data som författaren samlat in är igenom observationer, intervjuer samt analys av olika interna företagsdokument. Detta gjorde att författaren kunde jämföra sekundär-och primär-data samt kvalitativ-och kvantitativ-data. Problemet som företaget hade framför sig var av logistisk karaktär och upptäcktes i etikettproduktionsprocessen.</p><p>Produktionen av etiketter är onödigt komplicerad och ineffektiv pga icke kompatibla datasystem. Därför sker visa delar av skapandet av etiketter manuellt, även om företaget har ett scanning system. Efter viss analys blev det dock klart för författaren att problemet var lätt att ordna upp och att huvudpersonerna som var involverade, i etikett hanteringen, visste om att problemet var lätt löst men gjorde inget åt situationen. Detta ledde till att författaren fråga sig vad den underliggande orsaken, till detta problem, kunde vara. Varför har inte företaget gjort något åt problemet om det har varit uppenbart för dem att problemet existerar?</p><p>När all information sedan om analyserades, upptäckte författaren ett andra problem vilket inte var inom logistikområdet utan hade sina rötter i organisationens struktur. Problemet med överlappande auktoritet, samt ansvarsområden, gör det omöjligt för företaget att lösa deras logistiska problem inom etiketthanteringen. Därför måste detta problem ses över först, samtidigt som inställningen till förändring måste ändras för att göra det möjligt att skapa en ”problem-lösnings-process” i den logistiska delen.</p><p>Generellt visar denna fallstudie på relationen mellan logistik- och organisation och på den mycket komplicerade miljön som tillverkande företag ställs inför vid en förändring av sina processer.</p>
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Aspectos de crescimento e mortalidade do guanhumi (CARDISOMA GUANHUMI) em um manguezal de acesso restrito na Ilha de Itamaracá – PE

COSTA, Denise Fabiana de Moraes 19 August 2016 (has links)
Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-02-20T13:51:05Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação CD Biblioetca Denise Moraes 2016 FINAL.pdf: 2561125 bytes, checksum: 30370d4b25d98afe00850c78927ba185 (MD5) / Made available in DSpace on 2017-02-20T13:51:05Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação CD Biblioetca Denise Moraes 2016 FINAL.pdf: 2561125 bytes, checksum: 30370d4b25d98afe00850c78927ba185 (MD5) Previous issue date: 2016-08-19 / FACEPE / O conhecimento dos parâmetros de crescimento e mortalidade em braquiúros é fundamental para a compreensão da sua dinâmica e para o manejo de suas populações. Neste sentido, foram estimados os parâmetros de crescimento e mortalidade para Cardisoma guanhumi Latreille, 1825 (guaiamum), uma espécie com elevada importância socioeconômica no nordeste brasileiro e atualmente considerada pelo Ministério do Meio Ambiente como Criticamente em Perigo de extinção. As amostragens foram efetuadas durante um ano, entre abril de 2015 a março de 2016, na margem superior do mangue do CMA/ICMBio/CEPENE na ilha de Itamaracá, Pernambuco, Brasil. Foram capturados, medidos e pesados 1078 indivíduos (572 machos e 506 fêmeas). Destes, 291 indivíduos foram marcados com microchips PIT ("Passive Integrated Transponder"), para determinação dos parâmetros de crescimento através dos incrementos de peso e tamanho e do crescimento individual. Para a análise dos dados, foram utilizados o método ELEFAN I (baseado na distribuição de frequência de largura de carapaça de 1078 indivíduos), inserido no pacote computacional Fisat II e através da função GrowthTraject (baseada em incrementos individuais de 291 indivíduos marcados com PITs, utilizando o pacote fishmethods (Ambiente de programação “R”). Os indivíduos de C.guanhumi apresentaram largura da carapaça entre 20,9 e 70,0 mm (média: 43,45 mm, desvio padrão: 8,53 mm, mediana: 44,05 mm) o peso total entre 4 e 162 g (média: 45,85 g, desvio padrão: 25,34 g, mediana: 44,0 g). Não houve diferenças significativas, em tamanho médio e peso médio, entre machos e fêmeas. Os parâmetros de crescimento estimados com a função GrowthTraject para 130 incrementos (machos e fêmeas) foram: Linf (tamanho assintótico) = 108,03 mm (largura da carapaça); K (coeficiente de crescimento) = 0,145 ano-1. A Mortalidade total (Z) da população, estimada pelo método Length – converted Catch Curve (pacote FISAT II) usando os parâmetros de crescimento do GrowthTraject foi de = 2,39 ano-1. Não ocorrem capturas comerciais nesta área fechada, portanto, este valor equivale à mortalidade total e natural (Z=M). A idade dos indivíduos capturados variou de 1,49 anos (20,9mm) a 7,02 anos (70,0mm). O recrutamento, calculado no pacote FISAT II e estimado através da presença de juvenis, mostrou-se contínuo durante todo o ano. Os métodos de análises de frequência e comprimento inseridos no pacote FISAT (Bhattacharya, ELEFAN I e Shepherd’s) não foram capazes de determinar os parâmetros de crescimento, provavelmente devido ao crescimento lento e recrutamento contínuo durante todo ano. O tamanho total da população no manguezal do CMA foi estimado em 1262 indivíduos (+- 401ind.), baseado nos dados de marcação e recaptura. / Knowledge on the growth parameters and mortality in brachyuran is fundamental to the understanding of the dynamics and management of their populations. Growth and mortality parameters were estimated for Cardisoma guanhumi Latreille, 1825 (locally known as”guaiamum”), a species with high socio-economic importance in northeastern Brazil and currently considered by the Ministry of the Environment as Critically Endangered of Extinction. The samples were taken over one year, from April 2015 to March 2016, at the upper margin of a small, isolated mangrove patch at CMA-ICMBio-CEPENE on Itamaracá Island, Pernambuco, Brazil. A total of 1078 individuals (572 males and 506 females) were captured, measured and weighed. Of these, 291 individuals were marked with PIT tags (Passive Integrated Transponder tags), as to determine the growth parameters through the analysis of the increments in weight and size and individual growth. For the data analysis, we used the ELEFAN I method (based on the frequency distribution of carapace width 1078 individuals), inserted into the computer package FISAT II and through the GrowthTraject function (based on individual increments of 291 individuals marked with PIT tags, using the fishmethods package ("R” Environment). C. guanhumi showed carapace widths between 20.9 and 70.0 mm (mean: 43,45 mm, standard deviation: 8,53 mm, median: 44,05 mm) and total weight between 4 and 162 g (mean: 45,85 g, standard deviation: 25,34 g, median: 44,0 g). There were no significant differences in average size and average weight between males and females. Growth parameters estimated with the fishmethods package, based on 130 increments (males and females), were: L∞ (asymptotic carapace width) = 108.03 mm; K (coefficient growth) = 0.145 y-1. Total mortality (Z) of the population, estimated through the Length-converted catch Curve method (FISAT II package), using the fishmethods growth parameters, was 2.39 y-1. Since this is a restricted area without regular commercial catches, so this value is roughly equivalent to the total and natural mortality (Z = M). The age of the individuals captured ranged from 1.49 years (20,9 mm) to 7.02 years (70,0 mm). Recruitment, calculated in FISAT II package and estimated by the presence of juveniles, showed to be continuous throughout the year. The methods of length-frequency analysis inserted in the FISAT package (Bhattachary of protective measures for this species.
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Receptor super-regenetativo (900 MHz) implementado em tecnologia CMOS 0,35 'mu'm / Super regenerative receiver (900 MHz) in 0,35 'mu'm

Thiebaut, Matthieu Jacques Andre 12 August 2018 (has links)
Orientador: Carlos Alberto dos Reis Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-12T22:43:50Z (GMT). No. of bitstreams: 1 Thiebaut_MatthieuJacquesAndre_M.pdf: 11116037 bytes, checksum: 353c725fb0cc60a33445209f0ec29a81 (MD5) Previous issue date: 2006 / Resumo: O objetivo deste trabalho é propor uma topologia de receptor adequada para atender as exigências de uma rede de sensores sem fio, onde baixo consumo e baixo custo de fabricação são fundamentais.A topologia escolhida foi a do receptor super-regenerativo realizado em tecnologia CMOS 0,35Km e operando em 900 MHz. O chip foi montado e testado numa placa de alumina junto com alguns componentes passivos externos (circuito tanque e adaptação de impedância) necessários para seu funcionamento. Uma sensibilidade de -82 dBm para uma taxa de erro binário (BER) inferior a 0,1% foi obtida com um sinal modulado tudo-ou-nada (On-Off keying, OOK) de 64 kbits/s. O consumo deste receptor foi de 2,5 mW para uma tensão de alimentação de 2V. / Abstract: The purpose of this work is to develop a radio receiver, which is suitable for application in wireless sensor networks. Among the essential requirements for one such radio are included low power, low cost and high sensitivity. The topology of a super-regenerative receiver to operate in 900MHz was chosen, since it complies with all these requirements in addition to being appropriate for integration. Samples of the developed radio receiver were fabricated in 0,35Km CMOS technology. Prototypes were assembled on alumina plate using a few additional external components as an alternative to evaluate the performance of the radio without being affected by the low quality of the passives L and C used in the tuning block (tank and matching circuit). Test results have shown that the developed receiver features sensitivity of -82 dBm for a bit error rate (BER) lower than 0,1% with an On-Off Keying modulated signal of 64 kbit/s. Measure power consumption has been 2,5 mW for a supply voltage of 2 V. / Mestrado / Eletrônica, Microeletrônica e Optoeletrônica / Mestre em Engenharia Elétrica

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