Dissertations / Theses on the topic 'Forced drainage'

Je reporte ici une étude expérimentale sur la réorganisation inertielle de liquide dans un microcanal, constitutif des mousses liquides, appelé le bord de Plateau qui est soutenu par trois films de savon. Deux perturbations sont appliquées sur un bord de Plateau. Premièrement, une goutte y est ajoutée. La viscosité du liquide et taille initiale du bord de Plateau et de la goutte sont variés. La redistribution du liquide ajouté est pilotée par les forces capillaires. On observe un régime inertiel où un ressaut hydraulique capillaire se déplace à vitesse et géométrie constantes dans le bord de Plateau. Ce régime est décrit théoriquement et révèle le rôle majeur joué par les films de savon. On observe aussi un régime dominé par les effets visqueux où le liquide ajouté est redistribué selon une dynamique de type diffusive. La transition entre les deux régimes dépend des paramètres de contrôle du système et est caractérisée. La seconde perturbation est acoustique. Une plaque vibrante perturbe le bord de Plateau et les films. La taille du bord de Plateau, la fréquence et l’amplitude de forçage sont variées. Une onde de flexion se propage dans les films qui ont le bord de Plateau pour condition limite fixe ou libre selon sa masse. A haute amplitude, un régime non linéaire apparaît et le liquide dans le bord de Plateau se réorganise en trois zones de taille et d’amplitude d’oscillation très contrastées. Dans chacune des zones, le déphasage entre l’onde dans le film et l’onde dans le bord de Plateau est différent. Le système couplé du film et du bord de Plateau est modélisé par un oscillateur forcé dont la fréquence propre dépend de la fréquence de forçage
I report an experimental study of inertial liquid reorganization into a liquid foam microchannel, also called a Plateau border supported by three soap films. Two perturbations are applied on the Plateau border. Firstly, a liquid drop is injected. Liquid viscosity, drop size and Plateau border size are changed. The liquid redistribution is drived by capillary forces. We observe an inertial regime where a capillary hydraulic jump move on the Plateau border with a constant shape and a constant velocity. This regime is modeled and shows the importance of soap films. We also observe a viscous-dominated regime where the added liquid is redistributed with a diffusive-like dynamic. The transition between the two regimes is investigated and qualitatively accounted for. Secondly, the Plateau border and the three films are vibrated by a plate. A bending wave is shown to propagate in the soap films with the Plateau border for free or fixed limit conditions according to its mass. For high amplitudes, a non linear regime appears and the liquid inside the Plateau border is redistributed along three zones of very contrasted size and oscillation amplitudes. In each zone, the phase difference between the wave in soap films and the wave in Plateau border is different. The system composed of films and the Plateau border is modelled by a forced oscillator with a resonance frequency which depends on the forced frequency

La récupération des métaux issus de déchets d'équipements électriques et électroniques (DEEEs) présente un intérêt environnemental et économique. Une des étapes de ce processus est l'hydrométallurgie : les métaux contenus dans les broyats de DEEEs sont lixiviés par des solutions d'acides inorganiques concentrées. Dans ce contexte, les travaux de cette thèse explore l'utilisation d'une mousse liquide pour lixivier le cuivre. Les mousses liquides présentent deux intérêts majeurs : diminuer le volume de déchets liquides et bénéficier du pouvoir oxydant du gaz contenu dans les bulles. Deux réactifs nécessitant la présence de dioxygène pour dissoudre le cuivre ont été étudiés : l'acide chlorhydrique et l'hydroxylamine. Comparé à une solution, nous montrons que les mousses accélèrent la cinétique des réactions de dissolution du cuivre impliquant une phase gazeuse. Cet effet provient d'un transport plus rapide du dioxygène vers le métal. Afin d'étudier plus précisément ces phénomènes de transport, nous avons conçu un montage de drainage forcé. Celui-ci consiste à injecter à débit constant la solution moussante au sommet d'une colonne de mousse. Il permet ainsi d'uniformiser la vitesse du front de drainage dans la mousse. Nous observons alors deux régimes. Dans le premier régime, la quantité de cuivre dissout est limitée par le flux de protons atteignant la surface métallique. Elle augmente ainsi avec le débit imposé. Dans le second régime, cette quantité est limitée par le flux de dioxygène et elle diminue alors avec le débit. La structure de la mousse a donc une influence directe sur la quantité de cuivre dissout
Retrieving metals contained in waste from electric and electronic equipements (WEEEs) is an environnemental and economic challenge. One step of this process is hydrometallurgy : metals contained in crushed WEEEs are lixiviated by concentrated inorganic acid solutions. In this framework, we explore the use of liquid foams for copper lixiviation. Liquid foams have two main advantages : decreasing the liquid waste volume and benefiting from oxidizing properties of the bubble gas. Two reactants that require dioxygene to dissolve copper have been studied : hydrochloric acid and hydroxylamine. Compared to a solution, liquid foams increase the kinetics of copper dissolution reactions that imply a gas phase. This effet is due to a faster dioxygen transport to the metal. To go further into the understanding of these transport phenomena, we designed a forced drainage experimental setup. It consists in injecting the foaming solution at a constant flowrate on the top of a foam column. We then observe two regimes. In the first one, the dissolved copper quantity is limited by the protons flux that reaches the copper surface. Thus, this quantity increases with the set flowrate. In the second regime, it is limited by the dioxygene flux and so it decreases with the flowrate. Thus, the foam structure directly influence the copper dissolved quantity

The mining of sulphidic ore to extract metals such as zinc and copper produces huge quantities of waste material. The weathering and oxidation of the waste produces what is commonly known as Acid Mine Drainage (AMD), a dilute sulphuric acid rich in Fe(II) and heavy metals. This thesis serves to summarise five papers reporting how the precipitation of Fe(III) phases can attenuate the contamination of heavy metals by adsorption processes.

Schwertmannite (Fe8O8(OH)6SO4) is a common Fe(III) mineral precipitating in AMD environments at pH 3-4. The stability and surface chemistry of this mineral was investigated. It was shown that the stability depended strongly on pH and temperature, an increase in either promoted transformation to goethite (α-FeOOH). Two pH dependent surface species of SO42- were detected with infrared (ATR-FTIR) spectroscopy.

The adsorption of Cu(II), Pb(II) and Zn(II) to schwertmannite occurred at lower pH than to goethite, whereas Cd(II) adsorption occurred in a similar pH range on both schwertmannite and goethite. Extended x-ray absorption fine structure (EXAFS) spectroscopy suggests two surface species for Cu(II) and Cd(II) at the schwertmannite surface. Cu(II) adsorbs monodentately and Cd(II) bridging bidentately to adsorbed SO42-. Both metal ions also adsorb in a bridging bidentate mode to the surface hydroxyl groups. At pH 7.5 up to 2.7 μmol Cd(II) m-2 could be adsorbed to schwertmannite, indicating a large adsorption capacity for this mineral.

The acid-base properties of two NOM samples were characterised and could be well described as diprotic acids below pH 6. The adsorption of NOM to schwertmannite and goethite was very similar and adsorption occured in a very wide pH range.

High concentrations of NOM increased the adsorption of Cu(II) to goethite at low pH whereas a slight decrease was noted at low concentrations of NOM. No effect was detected in the schwertmannite system.

The formation of Fe(III) phases from precipitation of AMD was shown to be very pH dependent. At pH 5.5 a mixture of minerals, including schwertmannite, formed whereas at pH 7 only lepidocrocite (γ-FeOOH) formed. The concentration of Zn(II) in AMD could by adsorption/coprecipitation be reduced to environmentally acceptable levels.

Instituées au XIIème siècle, les wateringues doivent être regardées, malgré la critique, comme de véritables établissements publics. Plus que la recherche d'une plus-value, ces associations syndicales forcées de propriétaires exécutent un véritable service public. Leur soumission à un régime juridique et à un mode de fonctionnement particulier révèle le caractère atypique de ces institutions. Si celles-ci sont fortement attachées au concept de propriétés rurales, les mutations de la plaine maritime imposent de réfléchir sur l'évolution des rapports entre ruraux et urbains afin de refonder le système participatif et financier. De même, si les wateringues ont leurs compétences strictement définies par leurs statuts, elles étudient la possibilité de travailler de façon concertée avec les divers acteurs de l'eau afin d'adapter leur mode de fonctionnement aux exigences écologiques
In spite of certain criticisms, wateringues, created in the 12th century must be considered as genuine public institution. Rather than looking to make a profit, these compulsory landlord's unions offer a valuable service for the community. Their obedience to certain laws and to a specific functioning reveals the uncommon characteristics of these institutions. As those are strongly associated with the concept of rural property, changes of this type of land call for a reflection on the shifts of relationships between rural and urban populations, in order to redefine the participative and financial system. Although the status of wateringues strictly defines the competences, the various water-related participants are thinking of working together in order to adapt their functioning to ecological requirements

Thesis (MScAgric)--University of Stellenbosch, 2003.
ENGLISH ABSTRACT: Coal mining in South Africa is estimated to produce 200 Ml of acid mine drainage (AMD) per day in the Pretoria-Witwatersrand-Vereeniging (PWV) area alone, while electricity production resulted in approximately 27 Mt of ash in 2001. A large number of collieries in South Africa are tied to power stations where these two waste streams, acid mine drainage and fly ash, have the capacity to neutralize each other and provide an opportunity for co-disposal. The aim of this study was to investigate the reactions that occur during the co-disposal of fly ash leachate (FAL) and AMD and to examine the precipitates that result from the neutralisation reactions. Potentiometric titration was employed to investigate the neutralisation of Al-Fe salt solutions, simulating acid mine drainage (AMD), with alkaline solutions of Ca or Na hydroxide as well as fresh alkaline leachate from fly ash (FAL). The effectiveness of fly ash in removing metals and other salts from acid mine water was examined by analysing the neutralised water and modelling the results thermodynamically. Precipitates, prepared from large scale synthetic AMD and FAL co-disposal at various pH levels and Fe:Al ratios, were characterised according to composition, mineralogy and surface properties. The experimental neutralisation of synthetic acid mine drainage was achieved through titrating the components of SAMD (Fe and Al salt solutions) and solutions of various Fe:Al mole ratios with different bases in air and N2, and comparing the SAMD-FAL system with these simple acids and bases. The FAL used in all experiments was produced from fresh fly ash collected at Arnot power station. The SAMD was prepared as a solution with a pH of 2.5 and containing 12.7 mmol/L Al, 10.9 mmol/L Fe and 40.8 mmol/L SO4. The characterisation of reaction solids was achieved by collecting the precipitates formed from the co-disposal of FAL and SAMD with Fe:Al ratios of 7.3, 0.8 and 2.5. From the titration experiments it was found that upscale potentiometric titrations of SAMD show buffer zones at pH values of 3.5, 4, 6 and 10 corresponding to Fe(III)precipitation, Al precipitation, Fe(II) hydrolysis and oxidation, and Al redissolution, respectively, while downscale potentiometric titrations with SAMD show buffer zones at pH values 12 – 11, 9 and 4.5, which correspond to Fe oxidation and precipitation, Al precipitation and Al re-dissolution, respectively. A high concentration of Al in the simulated AMD inhibited the crystallinity of the precipitates and resulted in a large quantity of SO4 being removed from solution, which suggests that an aluminium sulphate phase is precipitating, but it is not crystalline and cannot be identified by XRD. Titrations performed up-scale by adding FAL to AMD showed near-complete metal and substantial SO4 removal from solution. The characterisation of reaction solids by x-ray diffraction, infrared spectroscopy, thermal gravimetric and differential thermal analysis revealed that the precipitates consist of poorly crystalline, highly Al-substituted goethite and ferrihydrite with large amounts of SO4 included in the structure. Poorly crystalline bayerite appears at a high pH and high Al concentration, and calcite is present in precipitates made by adding SAMD to FAL. High surface charges of between 330 cmolc/kg positive and 550 cmolc/kg negative charge and potentially large specific surface areas between 7 and 236 m2/g suggest a strong potential for the precipitates to function as low-grade adsorbents in wastewater treatment. The similarity of these ochre precipitates to soil minerals implies that land disposal of the neutralised solids is also viable.
AFRIKAANSE OPSOMMING: Steenkool mynbou in SA produseer na benaming 200 ML suur mynwater per dag in die PWV area alleenlik, terwyl opwekking van elektrisiteit naastenby 27 Mt vliegas geproduseer het in 2001. ’n Groot aantal steenkoolmyne in SA word verbind met kragsentrales, waar hierdie twee strome afval, suur mynwater en vliegas, die kapasiteit het om mekaar te neutraliseer en die weg te baan vir gesamentlike wegdoening. Die doel van hierdie studie was om die reaksies wat plaasvind gedurende gesamentlike wegdoening van vliegas loog (VAL) en suur mynwater (SMW) te ondersoek, asook die neerslae wat mag vorm as gevolg van neutralisasie reaksies. Potensiometriese titrasies was gebruik om die neutralisering tussen Al:Fe-sout oplossings te ondersoek as nabootsing van SMW met gebruikmaking van alkaliese oplossings van Ca of Na hidroksied asook vars loog van VA. Die effektiwiteit van VA om metale en soute uit SMW te verwyder was getoets deur outleding van die geneutraliseerde water en modellering van die termodinamika. Neerslae berei uit groot-skaal sintetiese SMW en VAL en met gelyktydige storting by verskeie pH vlakke en Fe:Al verhoudings, was gekarakteriseer volgens samestelling, mineralogie en oppervlak eienskappe. Die eksperimentele neutralisering van sintetiese suur mynwater (SSMW) was gedoen deur titrering van die SSMW komponente en oplossings van verskeie Fe:Al molêre verhoudings met verskillende basisse in lug en N2, en vergelyking van SSMW-VAL sisteem met hierdie eenvoudige sure en basisse. Die VAL gebruik in alle eksperimente was geproduseer van vliegas verkry van die Arnot kragsentrale. Die SSMW was berei as ’n oplossing met ’n pH van 2.5 en bevat 12.7 mmol/L Al, 10.9 mmol/L Fe en 40.8 mmol/L SO4. Die karakterisering van vastestowwe uit die reaksie was gedoen deur die bemonstering van neerslae gevorm as gevolg van die gelyktydige wegdoening van VAL en SSMW met Al:Fe verhoudings van 7.3, 0.8 en 2.5.Die was waargeneem in die titrasie eksperimente dat hoër-skaal potensiometriese titrasie van SSMW buffersones, by pH waardes 3.5, 4, 6 en 10, ooreenstem met Fe(III) presipitasie, Al presipitasie, Fe(II) hidrolise en oksidasie, en Al her oplossing, terwyl laer skaal potensiometriese titrasie met SSMW buffer sones by pH waardes 12 - 11, 9 en 4.5 ooreenstem met Fe(III) presipitasie en oksidasie, Al presipitasie en heroplossing respektiewelik. ’n Hoë konsentrasie Al in die sintetiese SMW het kristalliniteit van die neerslae geïnhibeer en veroorsaak dat ’n hoeveelheid SO4 uit oplossing verwyder is, wat suggereer dat die AlSO4 fase neerslaan maar nie kristallyn is en gevolglik nie opgetel word met x-straal diffraksie nie. Titrasies gedoen by hoërskaal deur byvoeging van VAL tot SSMW, het feitlik volledige metaal en SO4 verwydering uit oplossing getoon. Die karakterisering deur x-straal diffraksie, infrarooispektroskopie, termies gravimetries en differentiële termiese analise, het getoon dat die presipitate bestaan uit swak kristallyne, hoë Al-gesubstitueerde goethiet en ferrihidriet met groot hoeveelhede SO4 vasgevang in die struktuur. Swak kristallyne bayeriet verskyn by hoë pH en hoë Al-konsentrasies en kalsiet is teenwoordig in neerslae gevorm deur byvoeging van SSMW tot VAL. Hoë oppervlakladings van tussen 330 cmolc/kg positief en 550 cmolc/kg negatiewe lading en ook potensieel groot spesifieke oppervlak van tussen 7 en 236 m2/g, dui op ’n sterk potensiaal vir neerslae om as laegraadse adsorbeermiddels in afvalwaterbehandeling gebruik te word. Die ooreenstemming in hierdie geelbruin neerslae met grond minerale, impliseer dat die land storting van geneutraliseerde vastestowwe ook lewensvatbaar is.

Flotation is a process of separating particulate materials of different surface properties in a hydrodynamic environment, and is used extensively for separating different minerals from each other in the mining industry. In this process, air bubbles are introduced at the bottom of a particulate suspension (pulp), so that bubbles coated with hydrophobic particles rise to the top and form a froth phase while hydrophobic particles stay in suspension. The selectivity of the flotation process is determined by the hydrophobicity of the particulate materials involved, while the kinetics of the process is controlled by the hydrodynamic conditions and the disjoining pressures in the thin aqueous films between air bubbles and particles. In the present work, a mathematical model for the flotation process has been developed by considering both the hydrodynamic and surface chemical parameters. The model can describe the events occurring in both the pulp and froth phases of a mechanically-agitated flotation cell. The pulp-phase model is based on predicting the kinetics of bubble-particle attachment using the DLVO extended to include contributions from hydrophobic force and the theory of turbulent collision. The froth-phase model is based on predicting the rate of bubble-particle detachment by considering bubble coarsening and water recovery. The predictions from the overall flotation model are in general agreement with the results obtained in single-bubble flotation experiments and the flotation test results reported in literature. Since the model has been developed largely from first principles, it has predictive and diagnostic capabilities.
Ph. D.

Current problems on the interaction of complex liquids (i.e. droplets or foams) with complex surfaces (i.e. soft deformable or porous surfaces) are addressed in the following areas: (1) wetting of deformable substrates and surface forces, (2) kinetics of wetting and spreading of non-Newtonian liquids over porous substrates, (3) kinetics of spreading of non-Newtonian solutions over hair, (4) free drainage of foams produced from non-Newtonian solutions, and (5) foam drainage placed on porous substrates. Equilibrium of liquid droplets on deformable substrates was investigated and the effect of disjoining pressure action in the vicinity of the apparent three phase contact line was taken into account. It was proven that the deformation of soft solids is determined by the action of surface forces inside the transition zone. Spreading/imbibition of blood, which is a power law shear thinning non-Newtonian liquid, over a dry porous layer was investigated from both theoretical and experimental points of view. It was found that blood droplet spreading/imbibition over porous substrates shows two different behaviours: (i) partial wetting case with three subsequent stages: initial fast spreading, constant maximum droplet base and the shrinkage of the droplet base; (ii) complete wetting case with only two stages: initial fast spreading and the shrinkage of the droplet base. The wetting of hair tresses by aqueous solutions of two commercially available polymers, AculynTM 22 (A22) and AculynTM 33 (A33) was investigated experimentally. Both A22 and A33 solutions demonstrate well pronounced shear thinning behaviour. Initial contact angle of the A22 and A33 solutions on hair tresses was about 100o. The A22 droplets remained on the hair tress after spreading for at least half an hour. However, a fast penetration of the A33 droplets inside the hair tresses was observed when advancing contact angle in the course of spreading reached a critical value of about 60o. This could be explained by Cassie-Wenzel wetting transition which is caused by filling the pores inside the porous media by liquid. The influence of non-Newtonian rheology of A22 and A33 solutions on foam drainage was also investigated experimentally and a new theory of foam drainage was presented for the case of free drainage. For lowly viscous polymeric solutions and under the assumption of rigid surface of the Plateau border, the predicted values of the time evolution of the foam height and liquid content were in good agreement with the experimental data. However, in the case of highly viscous solutions an interfacial mobility at the surface of the Plateau border has to be taken into account. A completely new theory of foam drainage placed on porous substrate was developed. It was found that there are three different regimes of the process: (i) a rapid imbibition, the imbibition into the porous substrate dominates as compared with the foam drainage; (ii) an intermediate imbibition, that is, the imbibition into the porous substrate and the rate of drainage are comparable; (iii) a slow imbibition, the rate of drainage inside the foam is higher than the imbibition into the porous substrate for a period of time and a free liquid layer is formed over the porous substrate.

Beim Bergbau werden bestehende Ökosysteme in großem Maße beeinflusst. Im ehemaligen Uranbergwerk Königstein (Sachsen) wurde die Umwelt durch den Einsatz von chemischen Säuren zur Lösung des Urans aus dem Erz (Laugung) in Folge der Verschiebung des pH-Wertes zusätzlich belastet. Durch diesen Prozess entstand eine Umgebung, die einen niedrigen pH-Wert und hohe Konzentrationen an gelösten Schwermetall-Ionen aufweist. Die komplexe mikrobielle Lebensgemeinschaft verschob sich daraufhin, indem sich bevorzugt säuretolerante und Schwermetall-tolerante Mikroorganismen durchsetzten. Diese Mikroorganismen wurden durch die Flutung der unter Tage Schächte im Jahr 2010 in ihrer Zusammensetzung erneut beeinflusst. In dieser Arbeit wurde die mikrobielle Biozönose nach Flutung der unter Tage Schächte des ehemaligen Uranbergwerkes Königstein charakterisiert und mit den Ergebnissen der mikrobiellen Diversität vor dem Flutungsprozess verglichen. Hierfür kam ein breites Spektrum an Methoden zum Einsatz, das klassische mikrobiologische Methoden und molekularbiologische Techniken umfasste. Die Analysen erfolgten dabei über mehrere Jahre hinweg, um die Variabilität der mikrobiellen Population im Grubenwasser planktonisch und im Biofilm zu erfassen.

La radiologie interventionnelle (RI) présente des avantages indéniables. Grâce aux techniques d’embolisation, les patients présentant des hémorragies pouvant engager le pronostic vital, peuvent être traités. Les agents liquides collants peuvent être utilisés or, leur technique d’utilisation reste très empirique. Les complications des embolisations à la colle peuvent être gravissimes. Leur maniabilité peut être appréhendée. Dans la 1ère partie de ce travail nous avons étudié in vitro les caractéristiques de plusieurs colles et notamment les dernières mises sur le marché (Glubran 2 et Purefill, par rapport à l’Histoacryl), en fonction de leur préparation (température, ratio du mélange avec le lipiodol). Nous avons également étudié les temps caractéristiques de ces 3 colles. La 2ème partie de ce travail a porté sur la RI appliquée à l’oncologie. Elle est scindée en plusieurs travaux ayant comme objectif commun l’optimisation des techniques de RI en hépato-biliaire. Une étude clinique a porté sur l’intérêt et la sécurité des biopsies endobiliaires. Une étude a consisté en la réalisation d’une enquête de pratiques en chimio-embolisation artérielle (TACE) du carcinome hépato-cellulaire en France. Deux études ont porté sur la recherche in vitro du ou des meilleurs agents cytotoxiques sur des lignées cellulaires (mélanomes de l’uvée murines µ2 et µ2F et humaines mel 270 et OMM 1.3 et de cancer colo-rectal HT29, SW 48, SW 480, SW 620, HCT116, CaCo2) en condition de temps d’exposition court (30 minutes) pour imiter les conditions de TACE. L’objectif final était de pouvoir trouver le ou les agents cytotoxiques les plus efficaces pour optimiser les traitements par TACE des métastases hépatiques de ces 2 origines. Pour les mélanomes de l’uvée, il est apparu que le paclitaxel était significativement le meilleur agent parmi ceux testés. Pour les cellules de CRC, l’idarubicine était le meilleur agent cytotoxique, suivi par la gemcitabine Un dernier travail a été réalisé pour appréhender in vitro la partie embolisation de la TACE. L’embolisation a été assimilée à une hypoxie. Nous avons ainsi pu évaluer l’effet de l’hypoxie à 2 niveaux (1 % et 0.2 %) sur la viabilité cellulaire, après que celles-ci aient été mises en contact (30 minutes) avec de la chimiothérapie. Une hypoxie sévère entraine une chimiorésistance dans ces conditions d’évaluation. Ces travaux doivent amener à des études sur modèle animal ainsi qu’à la mise en place d’essais cliniques
Interventional radiology (IR) has undeniable advantages. With embolization techniques, patients with potentially life-threatening haemorrhage can be treated. Glue can be used but, their technique of use remains very empirical. The complications of glue embolization can be very serious. Their maneuverability can be apprehended. In the first part of this work we studied in vitro the characteristics of several glues and in particular the latest releases on the market (Glubran 2 and Purefill, compared to Histoacryl), according to their preparation (temperature, mixing ratio with lipiodol). We also studied the characteristic times of these 3 glues. The second part of this work focused on the RI applied to oncology. It is divided into several works with the common objective of optimizing the RI techniques in hepatobiliary. A clinical study focused on the interest and safety of endobiliary biopsies. A study consisted in the realization of a survey of practices in arterial chemo-embolization (TACE) of hepatocellular carcinoma in France. Two studies focused on in vitro research of the best cytotoxic agent (s) on cell lines (uveal melanoma murine u2 and μ2F and human mel 270 and OMM 1.3 and colorectal cancer HT29, SW 48, SW 480, SW 620, HCT116, CaCo2) under short exposure time (30 min) to mimic TACE conditions. For uveal melanomas, it was found that paclitaxel was significantly the best agent among those tested. For CRC cells, idarubicin was the best cytotoxic agent, followed by gemcitabine. The ultimate goal was to find the most effective cytotoxic agent (s) to optimize the TACE treatment of liver metastases from these 2 origins. A final work was done to apprehend in vitro the embolization part of the TACE. Embolization has been equated with hypoxia. We were able to evaluate the effect of 2-level hypoxia (1% and 0.2%) on cell viability after they were exposed (30 minutes) with chemotherapy. Severe hypoxia leads to chemoresistance under these conditions of evaluation. This work should lead to studies on animal models as well as the establishment of clinical trials

Um polieletrólito catiônico (poliamina), com baixo peso molecular e elevada densidade de carga, normalmente aplicado como agente coagulante do lixo aniônico, foi usado para estudos de retenção e drenagem na fabricação de papel. O uso do carboximentil celulose de sódio para simulação do teor de lixo aniônico e seu efeito na retenção de cargas minerais foi uma característica importante para este trabalho. Pode ser observado que o aumento da dosagem do polímero catiônico tanto melhora a retenção de cargas minerais, avaliada pela turbidez do filtrado, quanto melhora a drenagem do sistema, avaliada pela velocidade de escoamento. Entretanto, elevadas dosagens deste polímero comprometeram os resultados destes parâmetros devido à inversão de carga do sistema. Pode também ser confirmado que forças de cisalhamento excessivas prejudicam a retenção de cargas minerais. Ademais, um polianfótero, com peso molecular e densidade de carga elevados, contendo grupos positivo (N-[3-(N,N-dimetilamino)propil]acrilamida), negativo (ácido metileno butanodióico) e nulo (acrilamida) na mesma cadeia, foi testado como agente de resistência a seco do papel. Todos os estudos em nível molecular sobre o comportamento do polianfótero em solução e o seu comportamento de adsorção sobre superfícies modelos carregadas, em diferentes condições de pH e de força iônica, foram importantes para explicar tanto dos fenômenos de adsorção, envolvendo fibras celulósicas e polianfótero, quanto o seu efeito na resistência mecânica do papel. Foi observado que a solubilidade do polímero aumenta à medida que o pH se distancia do seu ponto isoelétrico, pHPIE 7,3, e reduz para valores de pH próximos ao pHPIE. O tamanho das estruturas do polianfótero depende do pH do meio de dispersão. As características de tamanho do polianfótero tanto sob a forma de cadeias individuais ou quanto sob a forma de agregados, foram medidas através da técnica de espalhamento dinâmico de luz. As propriedades viscoelásticas das camadas adsorvidas e a quantidade de polímero adsorvida foram medidas através da técnica da balança microgravimétrica com dissipação de energia. Estas duas determinações, associadas às imagens no microscópio de força atômica, foram importantes para o entendimento dos resultados práticos do uso do polianfótero como agente de resistência a seco do papel. Maiores resultados de resistência do papel, avaliada através da resistência à tração, foram alcançados para valores de pH próximos ao ponto isoelétrico onde foram encontrados o seguinte: (1) maiores tamanhos para as estruturas do polímero em solução, (2) maior quantidade de massa nas camadas adsorvidas e (3) a formação de camadas mais viscoelásticas. O fenômeno de separação de fases, associado à mudança da solubilidade do polímero em solução devido ao balanço dos grupos positivos e negativos ionizados ao longo da faixa de pH estudada, foi considerado o principal aspecto para a variação em tamanho dos agregados. Embora este polímero tenha apresentado comportamento antipolieletrólito devido à expansão da sua cadeia e ao aumento da densidade de carga com o aumento da força iônica, considerando o efeito da força iônica para pH 4,3, o comportamento de adsorção do polianfótero foi avaliado como o comportamento de um polieletrólito monocarregado de alta densidade de carga. Maiores e menores quantidades de massas adsorvidas foram encontradas para valores intermediários e extremos de força iônica, respectivamente. As interações eletrostáticas foram consideradas as principais responsáveis pela adsorção do polímero sobre superfícies carregadas. Entretanto, a blindagem de cargas foi considerada a explicação para os baixos valores de massa adsorvida para valores mais elevados de força iônica.
A cationic polyelectrolyte (polyamine), with low molecular weight and high charge density, usually applied as anionic trash coagulant, was used for the retention and drainage studies in the papermaking. The use of sodium carboxymethyl cellulose to simulate the anionic trash content and its effect on the filler retention was an important feature of the work. It could be noted that the increasing of the cationic polymer dosage improves both the filler retention, evaluated by the turbidity of the filtrate, and the system drainage, evaluated by the flow speed. However, high dosages of this polymer compromised the results of these parameters due to the reversal of the system charge. It can also be confirmed that excessive shear forces affect the filler retention. Furthermore, a polyampholyte, with high molecular weight and charge density, containing positive (N-[3-(N,N- dimethylamino)propyl]acrylamide), negative (methylene butanedioic acid), and neutral (acrylamide) groups in the same chain, was tested as a dry strength agent. All of the studies at molecular level concerning to the polyampholyte behavior in the solution and its adsorption behavior on charged model surfaces at different conditions of pH and ionic strength, were important to explain both the adsorption phenomena, involving cellulosic fibers and polyampholyte, and its impact on the paper strength. It was observed that the polymer solubility increases as the pH moves away from its isoelectric point, pHIEP 7.3, and decreases when the pH approaches close to pHIEP. The sizes of the structures of the polyampholytes depend on the pH of the dispersion medium. Also the size characteristics of polyampholyte, both in individual and aggregated forms, were measured by dynamic light scattering technique. The viscoelastic properties of adsorbed layers, as well as the amount of the adsorbed polymer, were measured by quartz crystal microbalance technique with energy dissipation. These two measurements, associated with the atomic force microscopy images, were important to understand the practical results of polyampholyte usage as a dry strength agent. Best results of paper strength, evaluated by paper strength index, were achieved at pH close to the isoelectric point on which one were found the following features: (1) larger sizes of the polymer structures in solution, (2) higher amount of mass in the adsorbed layers, and (3) the formation of more viscoelastic layers. The phase separation phenomenon, associated with the change in the solubility of the polymer due to the balance of the positive and negative groups throughout the studied pH range, was considered the main aspect for the variation in size of the aggregates. Although this polymer shows antipolyelectrolyte behavior due to the expansion of the its chain and the increasing in charge density with the ionic strength, considering the effect of ionic strength at pH 4.3, the adsorption behavior of polyampholyte was evaluated as a monocharged polyelectrolyte behavior with high charge density. Major and minor amounts of adsorbed masses were found for intermediates and extremes values of ionic strength, respectively. The electrostatic interactions were considered the main cause of the adsorption on charged surfaces. However, the electrostatic screening was considered the explanation for the low values of adsorbed mass at higher values of ionic strength.

碩士
高苑科技大學
土木工程研究所
105
Kaohsiung City, "Okayama Air Force Airport," the southeast region of the drainage into the lake and the bottom of the lake and other snail Lake neighborhood, because the region is a low-lying area of Okayama location for many years for showers, rain or Dianbaoxi tidal water flooding that caused the Regional water. To explore whether to use the "South-North Water Diversion" as a drainage strategy in the airport to cut the lowland runoff on the south side of the airport to the north side of Yu Kung River to improve the water problem in the airport and alleviate the drainage load in the south- , Explore the feasibility of the program as follows: First, the south side of the airport and the west side of the drainage area Liu Lo drainage drainage area of Liu Causeway to the north side of the closure of a public store outlet drainage area. Second, the airport east side of the tail discharge area of part of the runoff to the northwest side of the Yancheng drainage area exports to discharge to the public store Creek.