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There were three main driving forces behind this thesis: global concern over climate change mainly due to uncontrolled carbon dioxide (CO2) emissions, the excitement over the discovery of graphene and its versatile potential, and the potential to design three-dimensional (3D) or two-dimensional (2D) structures, in our case using unique triptycene molecule. We examined two polymeric materials for CO2 adsorption and suggested simple design of disordered carbons suitable for gas adsorption studies. The approach in each task was to examine structural and adsorption properties of materials using detailed atomistic modelling employing Monte Carlo and Molecular Dynamics techniques and where possible provide experimental measurements to validate the simulations. The thesis is presented as a collection of papers and the work can be divided into three independent projects. The aim of the first project is to utilize graphene as an additive in polymer composites in order to increase separation between the polymer chains increasing available surface area. The matrix used is a polymer of intrinsic microporosity (PIM-1), which possess large surface area and narrow nano-sized ( > 2nm) pore distribution attractive for gas separation membrane applications. Adding a filler can reduce aging of the polymer, and enhance permeability across the membrane, often to the expense of loosing selectivity. Therefore, we investigated the packing of PIM-1 chains in presence of discrete 2D graphene platelets and 3D graphene-derived structures and its effect on composite structure and adsorption properties. We found that additives do not alter structural polymer properties at the molecular level preserving the same adsorption capacity and affinity. Potential permeability increase would benefit from the retention of selectivity in the material. Building on design philosophy of materials with intrinsic microporosity we continued further investigation of 3D graphene-derived structures. The idea is that highly concave molecules or polymer chains pack inefficiently creating microporous materials with sufficient surface area for gas adsorption. 3D propeller-like structures were derived from graphene arms connected through the rigid triptycene and other types of cores. The resulting structures created a large amount of micropores and showed similar CO2/CH4 selectivity to activated carbons reported in the literature. It was shown that rigid triptycene core leads to more open structures. The model was also applied to model commercially available activated carbon to predict n- perfluorohexane adsorption. The fitting to experimental structural information proved to be challenging due to trial and error nature of the approach. Nevertheless, the simple packing procedure and diverse structure design have a great potential to serve as a virtual model for porous carbons that possess pore complexity and does not require any previous experimental data to be build on. The last project concerns CO2 adsorption and selectivity over CH4 and N2 in recently reported triptycene-based polymer. The triptycene shape polymer can form a porous 2D network that can be exfoliated into free-standing sheets and potentially used as a membrane. Sheets stack in the bulk material forming anisotropic channel pores. Additionally it contains fluoro- functional groups, which are known to have a high CO2 affinity. We explored pore structure and chemistry of stacked material for gas adsorption and predicted comparable capacity and CO2 selectivity to other microporous covalent materials such as activated carbons and PIMs. The CH4/N2 selectivity was similar to currently most selective material belonging to MOF family. We showed that fluoro-group have a positive effect on CO2 affinity, however predictions are sensitive to the charges of fluorine atoms assigned by different methods.

The understanding of multiphase flow properties is essential for the exploitation of hydrocarbon reserves in a reservoir; these properties in turn are dependent on the geometric properties and connectivity of the pore space. The determination of the pore size distribution in carbonate reservoirs remains challenging; carbonates exhibit complex pore structures comprising length scales from nanometers to several centimeters. A major challenge to the accurate evaluation of these reservoirs is accounting for pore scale heterogeneity on multiple scales. This is the topic of this thesis. Conventionally, this micron scale information is achieved either by building stochastic models using 2D images or by combining log and laboratory data to classify pore types and their behaviour. None of these capture the true 3D connectivity vital for flow characterisation. We present here an approach to build realistic 3D network models across a range of scales to improve property estimation through employment of X-ray micro-Computed Tomography (μCT) and Focussed Ion Beam Tomography (FIBT). The submicron, or microporous, regions are delineated through a differential imaging technique undertaken on x-ray CT providing a qualitative description of microporosity. Various 3-Phase segmentation methods are then applied for quantitative characterisation of those regions utilising the attenuation coefficient values from the 3D tomographic images. X-ray micro-CT is resolution limited and can not resolve the detailed geometrical features of the submicron pores. FIB tomography is used to image the 3D pore structure of submicron pores down to a scale of tens of nanometers. We describe the experimental development and subsequent image processing including issues and difficulties resolved at various stages. The developed methodology is implemented on cores from producing wackstone and grainstone reservoirs. Pore network models are generated to characterise the 3D interconnectivity of pores. We perform the simulations of petrophysical properties (permeability and formation resistivity) directly on the submicron scale image data. Simulated drainage capillary pressure curves are matched with the experimental data. We also present some preliminary results for the integration of multiscale pore information to build dual-scale network models. The integration of multiscale data allows one to select appropriate effective medium theories to incorporate sub-micron structure into property calculations at macro scale giving a more realistic estimation of properties.

The understanding of multiphase flow properties is essential for the exploitation of hydrocarbon reserves in a reservoir; these properties in turn are dependent on the geometric properties and connectivity of the pore space. The determination of the pore size distribution in carbonate reservoirs remains challenging; carbonates exhibit complex pore structures comprising length scales from nanometers to several centimeters. A major challenge to the accurate evaluation of these reservoirs is accounting for pore scale heterogeneity on multiple scales. This is the topic of this thesis. Conventionally, this micron scale information is achieved either by building stochastic models using 2D images or by combining log and laboratory data to classify pore types and their behaviour. None of these capture the true 3D connectivity vital for flow characterisation. We present here an approach to build realistic 3D network models across a range of scales to improve property estimation through employment of X-ray micro-Computed Tomography (μCT) and Focussed Ion Beam Tomography (FIBT). The submicron, or microporous, regions are delineated through a differential imaging technique undertaken on x-ray CT providing a qualitative description of microporosity. Various 3-Phase segmentation methods are then applied for quantitative characterisation of those regions utilising the attenuation coefficient values from the 3D tomographic images. X-ray micro-CT is resolution limited and can not resolve the detailed geometrical features of the submicron pores. FIB tomography is used to image the 3D pore structure of submicron pores down to a scale of tens of nanometers. We describe the experimental development and subsequent image processing including issues and difficulties resolved at various stages. The developed methodology is implemented on cores from producing wackstone and grainstone reservoirs. Pore network models are generated to characterise the 3D interconnectivity of pores. We perform the simulations of petrophysical properties (permeability and formation resistivity) directly on the submicron scale image data. Simulated drainage capillary pressure curves are matched with the experimental data. We also present some preliminary results for the integration of multiscale pore information to build dual-scale network models. The integration of multiscale data allows one to select appropriate effective medium theories to incorporate sub-micron structure into property calculations at macro scale giving a more realistic estimation of properties.

The topic of this thesis is the formation of microporosity in cast test bars of nickel-base superalloy Inconel 713LC during solidification. The theoretical part consists of nickel alloys, their macrostructure, the method of casting and crystallization of nickel-based superalloys. The second part is devoted to the design of casting conditions, the production of shell molds, the size and shape of grains, evaluation of microporosity by various available methods, comparing the influence of grain size and the proportion of microporosity on the resulting values of the mechanical tests. Experiments were carried out in cooperation with PBS Velká Bíteš and ÚST foundry department.

We report a rapid additive-free synthesis of nanocrystals (NCs) of RHO-type ZIF-71 (1) of composition [Zn(dcim)₂] (dcim = 4,5-dichloroimidazolate) in 1-propanol as solvent at room temperature. NC-1 has a size of 30–60 nm and exhibits permanent microporosity with a surface area (SBET = 970 m² g−¹) comparable to that of microcrystalline material. When kept under the mother solution NC-1 undergoes transformation into a novel SOD-type polymorph (2), which in turn converts into known ZIF-72 (3) with lcs topology. It is shown that microcrystals (MCs) of 2 can be favourably synthesised using 1-methylimidazole as a coordination modulator. NC-2 with size <200 nm was prepared using NC-ZIF-8 as a template with SOD topology in a solvent assisted ligand exchange-related process. DFT-assisted Rietveld analysis of powder XRD data revealed that novel polymorph 2 possesses an unusual SOD framework conformation. 2 was further characterised with regard to microporosity (SBET = 597 m² g−¹) and thermal as well as chemical stability. DFT calculations were performed to search for further potentially existing but not-yet synthesised polymorphs in the [Zn(dcim)₂] system.

Made available in DSpace on 2017-07-25T19:30:02Z (GMT). No. of bitstreams: 1 Andre Carlos Auler.pdf: 1218277 bytes, checksum: aedcd75095720ba4b41e7ad48e647731 (MD5) Previous issue date: 2014-07-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Liming is the practice used to correct soil acidity and its reaction is dependent on the mode of application of the lime. The addition of lime to the soil with the tilling is an alternative for increasing his reaction. However, tillage alters its structure and processes occurring in it. The aim of this study was to evaluate the influence of liming of liming in three modes of application of limestone (on the surface, incorporated with plowing and harrowing and subsoiling and disking) on the physico-hydrical attributes of a Dystrudept. For this, an experiment was installed in the field with banded design, with treatments in a factorial arrangement (3 × 2). Treatments formed from the combination of two rates of lime (0 and 15 Mg ha-1) and three modes of application of limestone (on the surface, incorporate with plowing and harrowing and subsoiling and harrowing). Undisturbed and disturbed soil samples were collected at 0-0.10 and 0.10-0.20 m layers between plant rows of corn 18 months after installation of the experiment. The water-dispersed clay (WDC), flocculation degree (FD), bulk density (BD), total porosity (TP), water retention curves, pore size distribution curve, particle size and soil chemical properties were determined order to diagnose the effects of liming the soil studied. Liming effects on the physico-hydrical attributes of the soil were restricted to 0-0.10 m layer. The WDC and the FD were influenced by tillage, but not by liming. When liming was performed on the surface, there was a reduction of the DB and increased TP. In all modes of application of limestone, liming increased water retention and altered the distribution of pores. To conclude, the changes in physico-hydrical attributes of the soil were mostly due to the increase of pH and replacement of aluminum by calcium and magnesium in the exchange complex. / A calagem é a prática empregada na correção da acidez do solo e sua reação depende do modo de aplicação do corretivo. A incorporação de calcário com o revolvimento do solo é uma alternativa para o aumento da reação. Porém, a mobilização do solo altera a sua estrutura e os processos que nela ocorrem. O objetivo deste trabalho foi avaliar a influência da calagem em três modos de aplicação do calcário (na superfície, incorporada com aração e gradagem e com subsolagem e gradagem) nos atributos físico-hídricos de um CAMBISSOLO HÁPLICO Alumínico. Para isso, instalou-se um experimento em campo com delineamento em faixas, com tratamentos em arranjo fatorial (3 × 2). Os tratamentos constituíam-se da combinação de duas doses de calcário (0 e 15 Mg ha-1) e três modos de aplicação do calcário (na superfície, incorporado com aração e gradagem e subsolagem e gradagem). Amostras indeformadas e deformadas de solo nas camadas 0-0,10 e 0,10-0,20 m foram coletadas nas entrelinhas da cultura do milho 18 meses após a instalação do experimento. Foram avaliados os teores de argila dispersa em água (ADA), grau de floculação (GF), densidade do solo (Ds), porosidade total (Pt), curvas de retenção de água, curva de distribuição de poros, granulometria e atributos químicos do solo. Os efeitos da calagem sobre os atributos físico-hídricos do solo foram restritos à camada 0-0,10 m. A ADA e o GF foram influenciados pelo modo de aplicação do calcário, mas não pela calagem. Quando a calagem foi realizada na superfície, ocorreu redução da DS e aumento da Pt. Em todos os modos de aplicação do calcário, a calagem aumentou a retenção de água e alterou a distribuição de poros. Concluiu-se que as alterações nos atributos físico-hídricos do solo foram em sua maioria decorrentes do aumento do pH e da substituição do alumínio por cálcio e magnésio no complexo de troca.

The primary objective was to predict the relative storage capacity of carbonate rocks relevant for carbon dioxide sequestration. To achieve this, a detailed pore scale characterization of model carbonate rocks, Indiana Limestone and Pink Dolomite, was conducted utilizing micro-computed tomography (microCT) data using pore network modeling and invasion percolation simulations. For the first time in literature, Pink Dolomite’s pore space characteristics were analyzed. A secondary objective was to compare thresholding techniques as applied to carbonates which exhibit dual porosity (porosity at multiple length scales). The analysis showed the sensitivity of existing methods to the thresholding technique, imaging method and material. Overall, the contributions of this work provide an assessment of two carbonates relevant for carbon capture and storage at the pore scale; and a preliminary assessment into thresholding dual porosity carbonates.

The primary objective was to predict the relative storage capacity of carbonate rocks relevant for carbon dioxide sequestration. To achieve this, a detailed pore scale characterization of model carbonate rocks, Indiana Limestone and Pink Dolomite, was conducted utilizing micro-computed tomography (microCT) data using pore network modeling and invasion percolation simulations. For the first time in literature, Pink Dolomite’s pore space characteristics were analyzed. A secondary objective was to compare thresholding techniques as applied to carbonates which exhibit dual porosity (porosity at multiple length scales). The analysis showed the sensitivity of existing methods to the thresholding technique, imaging method and material. Overall, the contributions of this work provide an assessment of two carbonates relevant for carbon capture and storage at the pore scale; and a preliminary assessment into thresholding dual porosity carbonates.

The following monoethynylated N-benzylidene-2-hydroxyanilines were prepared: N-(4- ethynylbenzylidene)-2-hydroxyaniline, N-(3-ethynylbenzylidene)-2-hydroxyaniline, N-(4- ethynylbenzylidene)-2-hydroxy-5-nitroaniline and N-(3-ethynylbenzylidene)-2-hydroxy-5- nitroaniline, which differed in the position of the ethynyl group on the benzylidene ring and the substitution of the hydroxyaniline ring. Monoethynylated N-benzylidene-2- hydroxyanilines were used as the monomers for the chain-growth coordination homo- and copolymerization. The homopolymerization resulted in linear polyacetylene homopolymers with N-benzylidene-2-hydroxyaniline substituents. The copolymerization with multiethynylarene-type cross-linkers provided densely cross-linked copolymeric polyacetylene networks. The linear units of the networks carried N-benzylidene-2- hydroxyaniline substituents, the interconnection between the chains of the networks being realized by arene links. The texture parameters of the prepared networks significantly depended on the type of comonomers used. The highest specific surface area values (~530 m2 /g) were achieved with networks prepared by copolymerization of N-(4- ethynylbenzylidene)-2-hydroxyaniline or N-(3-ethynylbenzylidene)-2-hydroxyaniline,with 4,4'-diethynylbiphenyl used as a cross-linker. Selected...