The aim of this project was to enhance the current state of knowledge of the void structure of paper, and pigments used to coat paper. The porosities and pore size distributions of consolidated pigments were measured using mercury porosimetry. Prior to this work, mercury porosimetry was rarely used in this field due to problems associated with the conventional interpretation of mercury porosimetry data. These problems were examined and two limitations of mercury porosimetry were addressed. Firstly, the shrinkage of compressible samples causes an apparent increase in void volume and secondly, large void spaces shielded by smaller ones are not intruded until anomalously high applied pressures of mercury are reached. The first limitation was overcome by means of a new correction procedure which, uniquely, also allows the measurement of the bulk modulus of the continuous solid phase of a porous sample. Shielding effects have been taken into account by means of a software package known as Pore-Cor, which generates a three dimensional structure which has both a mercury intrusion curve and porosity in close agreement with experiment. It has also been possible to calculate the permeabilities and tortuosity of the simulated structure and this provides realistic and useful values, which may not be measured experimentally. Mercury porosimetry and a range of specialised absorption techniques, including liquid porosimetry, were used to characterise the porous structures of a highly filled paper which had been calendered using a range of different conditions. A unique feature of this work is that for the first time it has been shown that two porosimetric techniques which measure overlapping pore size distributions may be combined to give a better indication of the total pore size distribution.

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Standard catalyst characterisation techniques such as gas adsorption porosimetry and mercury porosimetry only account for some of the physical heterogeneity of the catalyst surface. They completely ignore the chemical heterogeneity present and in most cases consider pores present in the medium to be independent of each other. Thus, most results of characterisation (pore space descriptors such as BET surface area, BJH pore size distribution, mercury porosimetry surface area, etc.) are not accurate. This has been a major issue that remains to be resolved during the characterisation of fresh and coked catalysts. In this thesis, the use of a multi-component adsorption system is recommended as a step-change solution to this limitation. Two approaches are adopted. Firstly, integrated nitrogen-waternitrogen gas adsorption experiments are performed on fresh and coked catalysts. This established the significance of pore coupling by showing the presence of advanced adsorption. The method also helped to determine the location of coke deposits within catalysts and indicated that water vapour adsorption was a good probe to understand the sites responsible for coking. Secondly, coadsorption of immiscible liquids – cyclohexane and water – was performed on fresh and coked catalysts following which the displacement of cyclohexane by water was studied using NMR relaxometry and diffusometry. This novel approach takes the wettability of the surface into consideration, unlike the former methods. It is therefore a method that accounts for the chemical heterogeneity of the surface. It also helped determine the location of coke within catalysts. The different approaches are presented in the context of combustion of heavy oil in bitumen reservoirs, and the use of supercritical conditions that help to dissolve coke precursors in the isomerisation of 1-hexene. Thus, the solutions provided in this thesis are directions in which catalyst characterisation, especially distinguishing fresh and coked catalysts, and other porous materials, must be carried out.

The content of this diploma thesis was testing the applicability of available structural analysis techniques on a appropriate model hydrogel system. The main aim was to evaluate the advantages and disadvantages of selected structural analysis techniques and the influence of the composition change of the hydrogel system on its internal structure. Semi-interpenetrated hydrogels based on agarose of different concentration were chosen as model system, this type of material was chosen for simple and repeatable preparation and also for its application potential. Electron microscopy (SEM, cryoSEM), mercury porosimetry and turbidimetry were chosen as structural analysis techniques. Experimental results could be used to improve knowledge about the influence of hydrogel composition on its structure and the comparison of chosen techniques will be used for the choice of appropriate structural analysis in the future, which will be applicable to other hydrogel systems as well.

The aim of this study was to determine the effect of quicklime (1 - 8% CaO) and maturation time (1 - 540 days) on the structure of clayey soil compacted at optimum moisture content by Proctor standard energy and whether expected change in structure affects the long - term permeability. The change of pore space of compacted loess with 1-8% lime (CaO) was studied by mercury porosimetry (MIP) for a long period of maturation (from 1 to 540 days). Development of pozzolanic reactions were monitored by measuring the pH. The development of new mineral phases (calcium silicate hydrates, calcium aluminate hydrates and calcium aluminate carbonate hydrate) in the treated soil was investigated by using X-Ray diffraction. The MIP indicated that 2% of CaO were sufficient for long term pozzolanic reaction. The threshold value is below the initial consumption of lime determined from the pH measurements (Eades and Grim, 1966). The alteration of the voids of the lime treated soil is noticeable, but the pH value can not drop below 11.7. At 4% of CaO, at 8% of CaO respectively, the macroporosity kept decreasing due to increasing mesoporosity for 360 curing days, for 540 curing days respectively, due to the new mineral phases. At 2% of CaO, the decrease of the macroporosity stops after 120 days. Below 2% of lime, the...

Alterations of fluid phase transitions in porous materials are conventionally employed for the characterization of mesoporous solids. In the first approximation, this may be based on the application of the Kelvin equation for gas–liquid and the Gibbs–Thomson equation for solid–liquid phase equilibria for obtaining pore size distributions. Herein, we provide a comparative analysis of different phase coexistences measured in mesoporous silica solids with different pore sizes and morphology. Instead of comparing the resulting pore size distributions, we rather compare the transitions directly by using a common coordinate for varying the experiment’s thermodynamic parameters based on the two equations mentioned. Both phase transitions in these coordinates produce comparable results for mesoporous solids of relatively large pore sizes. In contrast, marked differences are found for materials with smaller pore sizes. This illuminates the fact that, with reducing confinement sizes, thermodynamic fluctuations become increasingly important and different for different equilibria considered. In addition, we show that in the coordinate used for analysis, mercury intrusion matches perfectly with desorption and freezing transitions.

This thesis aims to find out the effective diffusivity (Deff) of a porous material – γ-alumina, using an unsteady state method with two inert gases at ambient condition with no reactions. For porous materials, Deff is important because it determines the amount of reactants that transfers to the surface of pores. When Deff is known, the apparent tortuosity factor of γ-alumina is calculated using the parallel pore model. The apparent tortuosity factor is important because: (a) it can be used to back-calculate Deff at reacting conditions; (b) once Deff with reactions is known, the Thiele modulus can be calculated and hence the global reaction rate can be found; (c) apparent tortuosity factor is also important for modelling purposes (e.g. modelling a packed-bed column or a catalytic combustion reactor packed with porous γ-alumina in various shapes and monoliths). Experimental measurements were performed to determine the effective diffusivity of a binary pair of non-reacting gases (He in N2, and N2 in He) in spherical γ-alumina pellets (1 mm diameter), and in γ-alumina washcoated monoliths (washcoat thickness 20 to 60 µm, on 400 cpsi (cells per square inch) cordierite support). The method used is based on the chromatographic technique, where a gas flows through a tube, which is packed with the sample to be tested. A pulse of tracer gas is injected (e.g. using sample loops: 0.1, 0.2, 0.5 ml) and by using an on-line mass spectrometer the response in the outlet of the packed bed is monitored over time. For the spherical pellets, the tube i.d. = 13.8 mm and the packed bed depths were 200 and 400 mm. For monoliths the tube i.d. = 7 mm and the packed lengths were 500 and 1000 mm. When the chromatographic technique was applied to the monoliths, it was observed that experimental errors can be significant, and it is very difficult to interpret the data. However, the technique worked well with the spherical pellets, and the effective diffusivity of He in N2 was 0.75 – 1.38 × 10-7 m2 s-1, and for N2 in He was 1.81 – 3.10 × 10-7 m2 s-1. Using the parallel pore model to back-calculate the apparent tortuosity factor, then a value between 5 to 9.5 was found for the pellets.

The diploma thesis deals with the observation and diagnostics of transformations that take place in stone slabs of different mineralogical composition during heating to high temperatures. The theoretical part of the thesis deals with a summary of available information about selected types of rocks. Furthermore, it presents findings from the experimental thermal loading of a granite sample. The principles and instruments of laboratory experimental methods that are used to judge the resistance of rocks are described in detail. In the experimental part, the testing methodology is proposed, the procedure of production of rock test specimens is described and the way in which the thermal loading of stone slabs took place is explained. The results of the experiments are shown in the tables and graphs. A comparison of individual tests and properties of selected samples and evaluation of the obtained results is performed.