Fluid flow process in fractured reservoirs is controlled primarily by the connectivity of fractures. The presence of fractures in these reservoirs significantly affects the mechanism of fluid flow. They have led to problems in the reservoir which results in early water breakthroughs, reduced tertiary recovery efficiency due to channeling of injected gas or fluids, dynamic calculations of recoverable hydrocarbons that are much less than static mass balance ones due to reservoir compartmentalization, and dramatic production changes due to changes in reservoir pressure as fractures close down as conduits. These often lead to reduced ultimate recoveries or higher production costs. Generally, modeling flow behavior and mass transport in fractured porous media is done using the dual-continuum concept in which fracture and matrix are modeled as two separate kinds of continua occupying the same control volume (element) in space. This type of numerical model cannot reproduce many commonly observed types of fractured reservoir behavior since they do not explicitly model the geometry of discrete fractures, solution features, and bedding that control flow pathway geometry. This inaccurate model of discrete feature connectivity results in inaccurate flow predictions in areas of the reservoir where there is not good well control. Discrete Fracture Networks (DFN) model has been developed to aid is solving some of these problems experienced by using the dual continuum models. The Discrete Fracture Networks (DFN) approach involves analysis and modeling which explicitly incorporates the geometry and properties of discrete features as a central component controlling flow and transport. DFN are stochastic models of fracture architecture that incorporate statistical scaling rules derived from analysis of fracture length, height, spacing, orientation, and aperture. This study is focused on developing a methodology for application of DFN to a shale gas reservoir and the practical application of DFN simulator (FracGen and NFflow) for fracture modeling of a shale gas reservoir and also studies the interaction of the different fracture properties on reservoir response. The most important results of the study are that a uniform fracture network distribution and fracture aperture produces the highest cumulative gas production for the different fracture networks and fracture/well properties considered.

This work is concerned with a better understanding of the influences that sparse long-chain branching has on the rheological and processing behavior of commercial metallocene polyethylene (mPE) resins. In order to clarify these influences, a series of six commercial polyethylenes was investigated. Four of these resins are mPE resins having varying degrees of long-chain branching and narrow molecular weight distribution. The remaining two resins are deemed controls and include a highly branched low-density polyethylene and a linear low-density polyethylene. Together, the effects of long-chain branching are considered with respect to the shear and extensional rheological properties, the melt fracture behavior, and the ability to accurately predict the flow through an abrupt 4:1 contraction geometry. The effects that sparse long-chain branching (M_branch > M_c) has on the shear and extensional rheological properties are analyzed in two separate treatments. The first focuses on the shear rheological properties of linear, sparsely branched, and highly branched PE systems. By employing a time-molecular weight superposition principle, the effects of molecular weight on the shear rheological properties are factored out. The results show that as little as 0.6 LCB/10⁴ carbons (<1 LCB/molecule) significantly increases the zero-shear viscosity, reduces the onset of shear-thinning behavior, and increases elasticity at low deformation rates when compared to linear materials of equivalent molecular weight. Conversely, a high degree of long-chain branching ultimately reduces the zero-shear viscosity. The second treatment focuses on the relationship between long-chain branching and extensional strain-hardening behavior. In this study, the McLeish-Larson molecular constitutive model is employed to relate long-chain branching to rheological behavior. The results show that extensional strain hardening arises from the presence of LCB in polyethylene resins, and that the frequency of branching in sparsely branched metallocene polyethylenes dictates the degree of strain hardening. This observation for the metallocene polyethylenes agrees well with the proposed mechanism for polymerization. The presence of long-chain branching profoundly alters the melt fracture behavior of commercial polyethylene resins. Results obtained from a sparsely branched metallocene polyethylene show that as few as one long-chain branch per two molecules was found to mitigate oscillatory slip-stick fracture often observed in linear polyethylenes. Furthermore, the presence and severity of gross melt fracture was found to increase with long-chain branching content. These indirect effects were correlated to an early onset of shear-thinning behavior and extensional strain hardening, respectively. Conversely, linear resins exhibiting a delayed onset of shear-thinning behavior and extensional strain softening were found to manifest pronounced slip-stick fracture and less severe gross melt fracture. The occurrence of surface melt fracture appeared to correlate best with the degree of shear thinning arising from both molecular weight distribution and long-chain branching. The ability to predict the flow behavior of long-chain branched and linear polyethylene resins was also investigated. Using the benchmark 4:1 planar contraction geometry, pressure profile measurements and predictions were obtained for a linear and branched polyethylene. Two sets of finite element method (FEM) predictions were obtained using a viscoelastic Phan-Thien/Tanner (PTT) model and an inelastic Generalized Newtonian Fluid (GNF) model. The results show that the predicted profiles for the linear PE resin were consistently more accurate than those of the branched PE resin, all of which were within 15% of the measured vales. Furthermore, the differences in the predictions provided by the two constitutive models was found to vary by less than 5% over the range of numerical simulations obtained. In the case of the branched PE resin, this range was very narrow due to loss of convergence. It was determined that the small differences between the PTT and GNF predictions were the result of the small contraction ratio utilized and the long relaxation behavior of the branched PE resin, which obscured the influence of extensional strain hardening on the pressure predictions. Hence, it was expected that numerical simulations of the 4:1 planar contraction flow for the mildly strain hardening metallocene polyethylenes would not be fruitful. / Ph. D.

The centrifugal casting process is a common method for manufacturing the tubes, etc. Due to its high temperature and invisible mold, it is really difficult to know the mechanism of molten steel inside the mold. It is important to know the mechanism of the molten steel inside mold, since it will help the manufacturer to know more accuracy of the flow of the molten steel so that it can work for improving the productivity and quality of the products. Casting funnel design is the designed by Åkers for their funnel which will result in different flow behavior. In thesis work, casting funnel design will be investigated so that it can make sure that the casting funnel design can affect the flow behavior of molten steel or not. Another method of changing the diameter of nozzle was also carried out and investigated with both simulation and experiment to changing flow behavior of molten steel. It will give Åkers alternative method for changing the flow behavior to liquid steel. The mechanism of solidification in centrifugal casting is also really important since it can give manufacturer the general view of solidification process. So solidification of centrifugal casting is also investigated in the thesis work.

No description available.

The press hardening belongs to state-of-the-art technology at sheet metal forming to gain high strength and crash resistant parts in automotive industry. This process could establish due to its cost- and esourceefficiency. According to ongoing developments on direct press hardening processes it is necessary to describe and understand the thermo-mechanical treatment of 22MnB5. Therefore the flow behavior and phase transformation during cooling with simultaneous forming is investigated. The experimental process considers industrial parameters in order to get industry-oriented results. In deep drawing processes the sheet metal is roped into the draw die and bended around the die edge. Thereby sheets perform different stages of compressive and tensile strain at the die oriented side and the punch oriented side of the sheet. There are different stages and values of stress and strain according to several layers of the sheet over its cross-section. The values of stress, strain and forming rate were FEcalculated for industry-relevant bending radii and sheet thicknesses of manganese-boron steel 22MnB5. According to the calculations different cooling and forming strategies were performed by dilatometric tests. The forming behavior is described by the microstructural development with regard to the cooling rate and temperature. Beside the influence of austenite forming on the phase transformation and mechanical properties is considered. A prospective view is given to illustrate ongoing examinations under compressive and combined tensional and compressive forces.

In this work, we have explored 2D semiconducting transition metal dichalcogenides (TMDs), black phosphorus (BP), and graphene for various applications using liquid and mechanical exfoliation routes. The topical areas of interest that motivate our work include considering factors such as device integration, stability, doping, and the effect of gasses to modulate the electronic transport characteristics of the underlying 2D materials. In the first area, we have integrated solution-processed transparent conducting oxides (TCOs), specifically indium-doped tin oxide (ITO) with BP, which is a commonly used TCO for solar cell devices. Here we have found surface treatment of glass substrates with a plasma before spin-coating the solution-processed ITO, to be effective in improving coverage and uniformity of the ITO film by promoting wettability and film adhesion. The maximum transmittance obtained was measured to be ~75% in the visible region, while electrical measurements made on BP/ITO heterostructures showed improved transport characteristics compared to the bare ITO film. Within the integration realm, inkjet-printing of BP and MoS2 p-n hetero-junctions on standard ITO glass substrates in a vertical architecture was also demonstrated. To address the issue of stability which some 2D materials such as BP face, we experimented with ionic liquids (ILs) to passivation the hydrophilic surface of BP to minimize its oxidative degradation. The enhanced stability of BP was inferred through Raman spectroscopy and scanning probe microscopy techniques, where no observable changes in the A1g and A2g Raman vibrational modes were observed for the BP films passivated with ILs over time under ambient conditions. On the other hand, a blue-shift in these Raman modes was evident for unpassivated samples. Atomic force microscopy measurements on the unpassivated samples clearly revealed the difference in surface characteristics through localized regions of degradation that intensified with time which was absent in IL passivated BP samples. The electronic device measurements for IL coated BP devices showed a more stabilized Ids−Vds characteristic in the 5.4 K to 335 K temperature range. Prototypical demonstrations of stabilized ILs/BP devices at ambient printed on flexible polyimide substrates were also successfully made. At the same time, doping is one of the essential steps required for the modulation of carrier density and electronic transport in electronic and optoelectronic devices, which is the third topical area we have addressed in this work with semiconducting TMDs. Of the conventional approaches used to dope 3D semiconductors, ion-implantation is commonly adopted but given the ultra-thin nature of 2D materials, this approach is not feasible as it causes severe damage to the delicate crystalline lattice of ultra-thin 2D membranes. Instead, we have used plasma-based doping routes with UV-ozone treatement and solution processing using 1,2 dichloroethane, to characterize the temperature-dependent two-terminal and three-terminal electronic and optoelectronic transport of mechanically exfoliated 2D MoS2 and WSe2. A significant difference was seen in the optoelectronic properties between the two dopants, owing to differences in their respective doping mechanisms and the intrinsic structural attributes of the exfoliated flakes. A significant reduction in barrier height was evident after doping using both techniques in MoS2, while an increase in barrier height after soaking in 1,2 dichloroethane was seen in WSe2. Lastly, in the fourth topical area for sensing devices, we have studied the effect of gas-flow in inkjet-printed and spin-coated graphene and MoS2 to modulate the electronic transport for the 2D materials since their increased surface area is an ideal platform to observe interactions with external stimuli, in this case, in-coming gas species. Here, the chamber pressure and change in current with flow of gas was measured in the steady-state, as well as time-dependent dynamic transport toward nitrogen and carbon dioxide. We observed significant differences in the electrical response of mono-elemental graphene and binary MoS2, owing to differences in microstructure and joule heating response to the ambient gas. In conclusion, the findings obtained from our work will provide an important framework to help guide strategies in further improving integration schemes, stability, doping and sensing behavior driven by the unique structural attributes inherent to 2D materials for high-performance devices in the future.

Chromonic liquid crystals are a relatively new class of lyotropic liquid crystals. In an effort to understand this lyotropic phase better, studies on the phase behavior, defects formed in these systems and characterization of the order were performed. We studied three chromonic liquid crystal materials in nematic and biphasic regions: Sunset Yellow FCF (SSY, a food dye), a cationic perylene diimide derivative (PDI, a conducting dye) and cromolyn sodium (DSCG, a drug). For SSY chromonics in the nematic region, order parameters ( and ) were obtained by polarized Raman measurements. Using the order parameters the flow behavior was predicted and was found to be non-flow aligning. A comprehensive viscoelastic property set of SSY chromonics was obtained by studying the statics and dynamics of defects during the formation of planar aligned monodomain. Applications of PDI thin films as vapor sensors were explored; anisotropic electronic properties of oriented PDI films show good conductivity along the columns presumably arising from the overlap between the ? systems. In the biphasic region, growth and fluctuation of SSY tactoids and interesting patterns of biphasic DSCG under capillary geometry were observed; elastic properties and surface tension were estimated based on the shape of DSCG tactoids. Polymer dispersed lyotropic chromonic liquid crystals with different drop shapes and director configurations were also fabricated using various water-soluble polymers.

La construction des biosystèmes d’oxydation passive du méthane (BOPM) est une option économique et durable pour réduire les émissions de méthane des sites d’enfouissement de déchets et des effets subséquents du réchauffement climatique. Les BOPM sont constitués de deux couches principales: la couche d'oxydation du méthane (MOL) et la couche de distribution du gaz (GDL). L'oxydation du méthane se produit dans la MOL par les réactions biochimiques des bactéries méthanotrophes, et la GDL est construite sous la MOL pour intercepter et distribuer les émissions fugitives de biogaz à la base de la MOL. Fondamentalement, l'efficacité d'un BOPM est définie en fonction de l'efficacité d'oxydation du méthane dans la MOL. Par conséquent, il est indispensable de fournir des conditions adéquates pour les activités bactériennes des méthanotrophes. En plus des paramètres environnementaux, l'intensité et la distribution du biogaz influencent l'efficacité des BOPM, et ils peuvent rendre le matériau de la MOL - avec une grande capacité d'accueillir les activités bactériennes - inutilisables en termes d'oxydation du méthane sur place. L'effet de barrière capillaire le long de l'interface entre la GDL et la MOL peut provoquer des émissions localisées de méthane, due à la restriction ou la distribution non uniforme de l’écoulement ascendant du biogaz à la base de la MOL. L'objectif principal de cette étude est d'incorporer le comportement hydraulique non saturé des BOPM dans la conception des BOPM, afin d’assurer la facilité et la distribution adéquates de l'écoulement du biogaz à la base de la MOL. Les fonctions de perméabilité à l'air des matériaux utilisés pour construire la MOL des BOPM expérimentaux au site d’enfouissement des déchets de St Nicéphore (Québec, Canada), ainsi que celles d'autres de la littérature technique, ont été étudiés pour évaluer le comportement d'écoulement non saturé du gaz dans les matériaux et pour identifier le seuil de migration sans restriction du gaz. Ce dernier seuil a été introduit en tant que un paramètre de conception avec lequel le critère de conception recommandé ici, c’est à dire la longueur de la migration sans restriction de gaz (LMSG), a été défini. La LMSG est considérée comme la longueur le long de l'interface entre la GDL et la MOL où le biogaz peut migrer à travers la MOL sans restriction. En réalisant des simulations numériques avec SEEP/W, les effets de la pente de l'interface, des paramètres définissant la courbe de rétention d'eau, de la fonction de la conductivité hydraulique du matériau de la MOL sur la valeur de la LMSG (représentant la facilité d'écoulement du biogaz à l'interface) et de la distribution de l'humidité (et par conséquent celle du biogaz) ont été évalués. Selon les résultats des simulations, la conductivité hydraulique saturée et la distribution des tailles de pores du matériau de la MOL sont les paramètres les plus importants sur la distribution de l'humidité le long de l'interface. Ce dernier paramètre influe également sur la valeur du degré de saturation et donc la facilité du biogaz à la base de la MOL. La densité sèche du matériau de MOL est un autre paramètre qui contrôle la facilité d'écoulement ascendant du biogaz. Les limitations principales de la présente étude sont associées au nombre de matériaux de MOL testés et à l'incapacité de SEEP/W de considérer l'évapotranspiration. Toutefois, compte tenu des hypothèses raisonnables dans les simulations et en utilisant les données de la littérature, on a essayé de réduire ces limitations. En utilisant les résultats des expériences et des simulations numériques, des étapes et des considérations de conception pour la sélection du matériau de MOL et de la pente d'interface ont été proposées. En effet,le comportement hydraulique non saturé des matériaux serait intégré dans les nécessités de conception pour un BOPM efficace, de sorte que la capacité maximale possible d'oxydation du méthane du matériau de la MOL soit exploitée. / Abstract : Implementation of passive methane oxidation biosystems (PMOB) is a cost effective and sustainable solution to eliminate the methane emissions of landfills to the atmosphere and ensuing global warming effects. PMOBs consist of two main layers: methane oxidation layer (MOL) and gas distribution layer (GDL). The oxidation of methane occurs in MOL through the biochemical reactions of methanotrophic bacteria, and GDL is constructed beneath the MOL to intercept and distribute the fugitive biogas emissions at the base of MOL. Basically, the efficiency of a PMOB is defined based on the methane oxidation efficiency in MOL. Therefore, it is indispensable to provide adequate conditions for the bacterial activities of methanotrophs. In addition to the environmental parameters, the intensity and the distribution of the biogas reaching the MOL material influence the efficiency of PMOBs, and they may cause the MOL material possessing great capacity to host the bacterial activities to be unserviceable in terms of in field methane oxidation. The capillary barrier effect along the GDL MOL interface may provoke localized surface methane emissions, resulted from the restricted and/or non uniform distribution of upward flow of biogas at the base of MOL. The main focus of present study is to incorporate the unsaturated hydraulic behavior of PMOBs into the design of PMOBs, providing adequate ease and distribution of upward flow of biogas at the base of MOL. The air permeability functions of the materials used to construct the MOL of experimental PMOBs at the St Nicephore landfill (Quebec, Canada), along with other materials from the technical literature, were studied to evaluate the unsaturated gas flow behavior of the materials and to identify the threshold of unrestricted gas migration. This latter threshold was introduced as a design parameter based on which the recommended design criterion herein, i.e. the length of unrestricted gas migration (LUGM), was defined. LUGM is considered as the length along the GDL MOL interface along which biogas can migrate upwards without restriction. Performing sets of numerical simulations in SEEP/W, the effect of slope of interface and the parameters defining the water retention curve and hydraulic conductivity function of MOL material on value of LUGM (representing the ease of upward flow of biogas at the interface) and distribution of moisture (and therefore biogas) along the GDL MOL interface were assessed. The saturated hydraulic conductivity and the pore size distribution of the MOL material were the most influencing parameters in distribution of moisture along the interface. The latter parameter influences also the value of degree of saturation and therefore, the ease of biogas at the base of MOL. Dry density of MOL material is another parameter that controls the ease of upward flow of biogas. The main limitations of the present study are associated with the number of tested MOL materials and the inability of SEEP/W in considering the evapotranspiration. However, considering reasonable assumptions in simulations and using the data from the literature, it was attempted to reduce the limitations. Based on the results of experiments and numerical simulations, some design steps and considerations for selection of the MOL material and the slope of interface were suggested that incorporate the unsaturated hydraulic behavior into the design necessities for an efficient PMOB so that the maximum possible methane oxidation capacity of MOL material is exploited.

The present dissertation investigates the flow behavior of concentrated Kaolin slurries and furthermore novel rheological measurement-, analysis-, and assessment procedures for characterizing static and dynamic flow behavior in industrial and research applica- tions. Ten different Kaolins with divergent property profiles were investigated in detail. At first, novel measurement and analysis procedures are presented and the raw material inherent properties are correlated with the resulting flow characteristics. The results describe the structural building and breakdown (in both static and dynamic states) of concentrated Kaolin slurry suspensions with and without deflocculant and also the determination of the point of optimal deflocculant concentration through the develop- ment of a novel analysis method and linking of the parameters to a condition matrix. The results lead to a better understanding of the flow behavior of concentrated Kaolin slurries. Due to the use of a strict measurement protocol with a focus on the elimination of external disturbances on the determination of flow behavior, the phases of dynamic structure construction and destruction (with exclusion of temporal structure effects and vice versa) can be analyzed. It was identified that the construction of particle networks requires less energy than their destruction. Furthermore it could be demonstrated that the occurrence of a transient shear stress peak in kaolin slurries is the cause for the breakdown of an existing particle network and not, as conventionally reported, due to an insufficient measurement time. Moreover, through the combination and modification of two measurement protocols described here, manufacturing companies have a potentially useful tool for composition development and quality control without the necessity of purchasing a highly precise research rheometer. / In der vorliegenden Arbeit wird das Fließverhalten von konzentrierten Kaolinsuspensio- nen untersucht und neuartige rheologische Mess-, Analyse- und Bewertungsverfahren zur Charakterisierung der Belastungs- und Zeitabhängigkeit für Industrie- und Forschungsanwendungen vorgestellt. Hierzu wurden zehn Kaoline mit divergierenden Eigenschaftsprofilen untersucht. Zunächst werden neuartige Mess- und Analyseverfahren vorgestellt und die Eigenschaften der Rohstoffe mit den ermittelten Fließcharakteristika korreliert. Die Ergebnisse beschreiben den strukturellen Auf- und Abbau (zeit- und belastungsabhängig) von konzentrierten Kaolinsuspensionen mit und ohne Dispergierhilfsmitteleinsatz und darüber hinaus die Ermittlung der optimalen Dispergierhilfsmittelkonzentration durch Entwicklung einer neuartigen Analyse und Verknüpfung von Parametern an eine Bedingungsmatrix. Die Erkenntnisse tragen zum besseren Verständnis des Fließverhaltens konzentrierter Kaolinsuspensionen bei. Aufgrund der entwickelten Messvorschriften und der darin elementar verankerten Elimination von Störgrößen auf die Ermittlung des Fließverhaltens konnten die Phasen des strukturellen Auf- und Abbaus unter Belastung (unter Ausschluss von temporalen Struktureffekten und umgekehrt) analysiert werden. Es wurde festgestellt, dass die Konstruktion von Partikelnetzwerken weniger Energie benötigt, als deren Destruktion und das Auftreten des Schubspannungshügels auf den Zusammenbruch des Partikelnetzwerkes und nicht, wie allgemein beschrieben auf zu geringe Messzeiten zurück zu führen ist. Darüber hinaus wird der produzierenden Industrie, durch Abwandlung und Kombination zweier Messvorschriften ein Werkzeug zur Versatzentwicklung und Qualitätskontrolle, auch ohne die Notwendigkeit des Erwerbs von hochpräzisen Forschungsrheometern bereitgestellt.

The present dissertation investigates the flow behavior of concentrated Kaolin slurries and furthermore novel rheological measurement-, analysis-, and assessment procedures for characterizing static and dynamic flow behavior in industrial and research applica- tions. Ten different Kaolins with divergent property profiles were investigated in detail. At first, novel measurement and analysis procedures are presented and the raw material inherent properties are correlated with the resulting flow characteristics. The results describe the structural building and breakdown (in both static and dynamic states) of concentrated Kaolin slurry suspensions with and without deflocculant and also the determination of the point of optimal deflocculant concentration through the develop- ment of a novel analysis method and linking of the parameters to a condition matrix. The results lead to a better understanding of the flow behavior of concentrated Kaolin slurries. Due to the use of a strict measurement protocol with a focus on the elimination of external disturbances on the determination of flow behavior, the phases of dynamic structure construction and destruction (with exclusion of temporal structure effects and vice versa) can be analyzed. It was identified that the construction of particle networks requires less energy than their destruction. Furthermore it could be demonstrated that the occurrence of a transient shear stress peak in kaolin slurries is the cause for the breakdown of an existing particle network and not, as conventionally reported, due to an insufficient measurement time. Moreover, through the combination and modification of two measurement protocols described here, manufacturing companies have a potentially useful tool for composition development and quality control without the necessity of purchasing a highly precise research rheometer.:1. Einleitung und Problembeschreibung 1 2. Stand des Wissen 3 2.1. ToneundKaoline.............................. 4 2.1.1. EntstehungvonKaolinen...................... 5 2.1.2. KaolinalsRohstoff ......................... 6 2.1.3. DasMineralKaolinit........................ 6 2.2. BeschreibungderRheologie ........................ 8 2.2.1. DasZwei-Platten-Modell...................... 8 2.2.2. FließverhaltenundModelle .................... 9 2.2.3. Messsgeräte und Systeme für die Messung rheologischer Eigen- schaften ............................... 16 2.2.4. RheometrischeMessmethoden................... 21 2.3. ElektrostatischstabilisierteDispersionen . . . . . . . . . . . . . . . . . 25 2.4. Tonmineral-Wasser-Interaktionen ..................... 28 2.5. FließverhaltenvonKaolindispersionen................... 30 3. Rohstoffuntersuchungen 31 3.1. Reindichtebestimmung ........................... 31 3.2. Partikelgrößenanalyse............................ 32 3.2.1. SedimentationimSchwerefeld ................... 33 3.2.2. Laserbeugungs-Partikelgrößenanalyse . . . . . . . . . . . . . . . 34 3.3. SpezifischeOberfläche ........................... 35 3.4. BestimmungderlöslichenSalze ...................... 36 3.5. Kationenaustauschkapazität ........................ 37 3.6. Röntgenfluoreszenzanalyse ......................... 37 3.7. Röntgenbeugungsanalyse.......................... 38 4. Experimentelle Methodik 40 4.1. NormativeMineralphasenanalyse ..................... 40 ii 4.2. BerechnungderPartikelgrößenverteilung . . . . . . . . . . . . . . . . . 4.2.1. AuswertungnachDingerundFunk ................ 4.2.2. DasRRSB-Modell ......................... 4.3. HerstellungderDispersionen........................ 4.4. RheologischeUntersuchungen ....................... 4.4.1. DasMalvernKinexuspro+ .................... 4.4.2. Messmethode zur Bestimmung der Zeitabhängigkeit . . . . . . . 4.4.3. Messmethode zur Bestimmung der Belastungsabhängigkeit . . . 4.5. AuswertungdesSprungversuches ..................... 4.6. AuswertungderScherratenrampe ..................... 5. Wiederholbarkeit der entwickelten Messregime 6. Anpassung der Messregime an industrielle Bedingungen 6.1. RohrströmungeinerPotenzflüssigkeit ................... 6.2. NachweisderMesssystemfähigkeit..................... 7. Versuchsreihenentwicklung 7.1. UntersuchungdesFeststoffanteileinflusses. . . . . . . . . . . . . . . . . 7.2. Untersuchung des Einflusses des Verflüssigeranteils . . . . . . . . . . . . 8. Ergebnisse und Diskussion 8.1. Einfluss der Rohstoffparameter auf das Fließverhalten . . . . . . . . . . 8.1.1. Einfluss der Partikelgrößenverteilung . . . . . . . . . . . . . . . 8.1.2. EinflussderPGV-Modellparameter ................ 8.1.3. Einfluss der spezifischen Oberfläche auf das Fließverhalten . . . 8.1.4. Einfluss der Rohstoffmineralogie auf das Fließverhalten . . . . . 8.2. Untersuchung des Dispergierhilfsmitteleinfusses . . . . . . . . . . . . . 8.3. UntersuchungdesFeststoffanteileinflusses. . . . . . . . . . . . . . . . . 9. Modellierung der belastungsabhängigen Fließeigenschaften 10.Zusammenfassung und Ausblick Literaturverzeichnis Anhang / In der vorliegenden Arbeit wird das Fließverhalten von konzentrierten Kaolinsuspensio- nen untersucht und neuartige rheologische Mess-, Analyse- und Bewertungsverfahren zur Charakterisierung der Belastungs- und Zeitabhängigkeit für Industrie- und Forschungsanwendungen vorgestellt. Hierzu wurden zehn Kaoline mit divergierenden Eigenschaftsprofilen untersucht. Zunächst werden neuartige Mess- und Analyseverfahren vorgestellt und die Eigenschaften der Rohstoffe mit den ermittelten Fließcharakteristika korreliert. Die Ergebnisse beschreiben den strukturellen Auf- und Abbau (zeit- und belastungsabhängig) von konzentrierten Kaolinsuspensionen mit und ohne Dispergierhilfsmitteleinsatz und darüber hinaus die Ermittlung der optimalen Dispergierhilfsmittelkonzentration durch Entwicklung einer neuartigen Analyse und Verknüpfung von Parametern an eine Bedingungsmatrix. Die Erkenntnisse tragen zum besseren Verständnis des Fließverhaltens konzentrierter Kaolinsuspensionen bei. Aufgrund der entwickelten Messvorschriften und der darin elementar verankerten Elimination von Störgrößen auf die Ermittlung des Fließverhaltens konnten die Phasen des strukturellen Auf- und Abbaus unter Belastung (unter Ausschluss von temporalen Struktureffekten und umgekehrt) analysiert werden. Es wurde festgestellt, dass die Konstruktion von Partikelnetzwerken weniger Energie benötigt, als deren Destruktion und das Auftreten des Schubspannungshügels auf den Zusammenbruch des Partikelnetzwerkes und nicht, wie allgemein beschrieben auf zu geringe Messzeiten zurück zu führen ist. Darüber hinaus wird der produzierenden Industrie, durch Abwandlung und Kombination zweier Messvorschriften ein Werkzeug zur Versatzentwicklung und Qualitätskontrolle, auch ohne die Notwendigkeit des Erwerbs von hochpräzisen Forschungsrheometern bereitgestellt.:1. Einleitung und Problembeschreibung 1 2. Stand des Wissen 3 2.1. ToneundKaoline.............................. 4 2.1.1. EntstehungvonKaolinen...................... 5 2.1.2. KaolinalsRohstoff ......................... 6 2.1.3. DasMineralKaolinit........................ 6 2.2. BeschreibungderRheologie ........................ 8 2.2.1. DasZwei-Platten-Modell...................... 8 2.2.2. FließverhaltenundModelle .................... 9 2.2.3. Messsgeräte und Systeme für die Messung rheologischer Eigen- schaften ............................... 16 2.2.4. RheometrischeMessmethoden................... 21 2.3. ElektrostatischstabilisierteDispersionen . . . . . . . . . . . . . . . . . 25 2.4. Tonmineral-Wasser-Interaktionen ..................... 28 2.5. FließverhaltenvonKaolindispersionen................... 30 3. Rohstoffuntersuchungen 31 3.1. Reindichtebestimmung ........................... 31 3.2. Partikelgrößenanalyse............................ 32 3.2.1. SedimentationimSchwerefeld ................... 33 3.2.2. Laserbeugungs-Partikelgrößenanalyse . . . . . . . . . . . . . . . 34 3.3. SpezifischeOberfläche ........................... 35 3.4. BestimmungderlöslichenSalze ...................... 36 3.5. Kationenaustauschkapazität ........................ 37 3.6. Röntgenfluoreszenzanalyse ......................... 37 3.7. Röntgenbeugungsanalyse.......................... 38 4. Experimentelle Methodik 40 4.1. NormativeMineralphasenanalyse ..................... 40 ii 4.2. BerechnungderPartikelgrößenverteilung . . . . . . . . . . . . . . . . . 4.2.1. AuswertungnachDingerundFunk ................ 4.2.2. DasRRSB-Modell ......................... 4.3. HerstellungderDispersionen........................ 4.4. RheologischeUntersuchungen ....................... 4.4.1. DasMalvernKinexuspro+ .................... 4.4.2. Messmethode zur Bestimmung der Zeitabhängigkeit . . . . . . . 4.4.3. Messmethode zur Bestimmung der Belastungsabhängigkeit . . . 4.5. AuswertungdesSprungversuches ..................... 4.6. AuswertungderScherratenrampe ..................... 5. Wiederholbarkeit der entwickelten Messregime 6. Anpassung der Messregime an industrielle Bedingungen 6.1. RohrströmungeinerPotenzflüssigkeit ................... 6.2. NachweisderMesssystemfähigkeit..................... 7. Versuchsreihenentwicklung 7.1. UntersuchungdesFeststoffanteileinflusses. . . . . . . . . . . . . . . . . 7.2. Untersuchung des Einflusses des Verflüssigeranteils . . . . . . . . . . . . 8. Ergebnisse und Diskussion 8.1. Einfluss der Rohstoffparameter auf das Fließverhalten . . . . . . . . . . 8.1.1. Einfluss der Partikelgrößenverteilung . . . . . . . . . . . . . . . 8.1.2. EinflussderPGV-Modellparameter ................ 8.1.3. Einfluss der spezifischen Oberfläche auf das Fließverhalten . . . 8.1.4. Einfluss der Rohstoffmineralogie auf das Fließverhalten . . . . . 8.2. Untersuchung des Dispergierhilfsmitteleinfusses . . . . . . . . . . . . . 8.3. UntersuchungdesFeststoffanteileinflusses. . . . . . . . . . . . . . . . . 9. Modellierung der belastungsabhängigen Fließeigenschaften 10.Zusammenfassung und Ausblick Literaturverzeichnis Anhang