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]. Main material variables are chemical composition, particle shape, particle size distribution, agglomeration degree, porosity, crystal structure, impurity, and homogeneity of the powder. Process variables include sintering conditions such as compaction

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Abstract  

Nitrocellulose porosity was investigated by thermoporometry, based on melting point depression of liquid in limited space. Strange behaviour of water-saturated nitrocellulose was observed, which consisted of melting peak shifting of some of liquid. Thermal resistance, connected with limited contact area of nitrocellulose walls and water, is supposed as the source of phenomenon. Water is unable to completely penetrate into pores as nitrocellulose is a hydrophobic material, though prolonged stirring or boiling of mixture improves saturation. Thus total pore volume cannot be estimated correctly. In spite of this pore radius was calculated from obtained DSC curves. The results show good consistency for the same nitrocellulose materials, which proves that thermoporometry is a useful method of nitrocellulose characterisation.

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the development of porosity. Moreover, compared to the carbon materials before sulfonation, the carbon materials after sulfonation have lower specific surface area and total pore volume. These reductions can be due to partial destruction of the porous

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method The surface area and porosity of the supports (SiO 2 , Al 2 O 3 , TiO 2 ) and bimetallic 5%Pd–2%In/support catalysts were determined by the application of the BET equation and Dollim/Heal method, from the nitrogen adsorption data

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castings are normally (but not totally) limited to non-structural components that do not require such a heat treatment or welding. Porosity causes more rejected castings than any other factor. In cold-chamber die casting of aluminum alloys, air and

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) Gerke, H., 2006. Preferential-flow descriptions for structured soils. J. Plant Nutr. Soil Sci. 169. 1–19. Gerke, H. H. & van Genuchten, M. T., 1993. A dual-porosity model for simulating the preferential movement of water and

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The nuclear track technique (NTT) is used to enhance the porosity of silica micro-particles. The enhanced porosity is a result of the formation of surface and interior pores or tracks in the silica by the action of external and internal fission fragments. The fission tracks produced at the surface and within the interior of the micro-particles are a result of coating the particles with trace quantitities of uranium, instead of having trace quantities of uranium incorporated within the silica matrix.

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The capillary porosity of clinker phases, i.e. 3CaOSiO2, β2CaOSiO2, 3CaOAl2O3 and 4CaOAl2O3Fe2O3, at the early stages of hydration has been studied by the methods of Differential Scanning Calorimetry and nitrogen adsorption (BET). It was established that pores of 3–70 nm were formed during the hydration of 3CaOSiO2 and the maximum of their distribution was found at about 10 nm. The hydration of 2CaOSiO2 is much slower and the porosity is one order of magnitude lower. During the hydration of 3CaOAl2O3 the content of crystalline hexagonal hydrates prevailed and the porosity was in the range 5–90 nm with the average pore diameter of about 16 nm. This average pore diameter was much smaller for thermoporosimetry and lay at about 7 nm. The hydrated 4CaOAl2O3Fe2O3 sample had the porosity in the range 3–90 nm with the maximum of the pores distribution at about 4 nm. There are some differences between the porosities measured by BET and thermoporosimetry. Principally thermoporosimetry gives no information about larger capillary pores in the range 30–50 nm.

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Abstract

Porosity and water absorption of different binder/aggregate ratios of repair mortar and porous limestone were studied that were used in many Hungarian monuments. Different types of mortars were analyzed by using mercury intrusion porosimetry (MIP) and the water saturation method (WSM). Test results showed that there was a strong correlation between the absorption mechanism and the porosimetric characteristics. Mechanical properties of the tested mortars were observed earlier. Pore size distribution confirms that the total porosity increases with increasing aggregate content. Natural stones mainly have medium and large pore radii (1–100 μm) while repair mortars, even with increased aggregate ratio, have smaller pore radii (0.01–0.1 μm). The comparison of different data allows us to state that pore characteristics such as pore volume, pore geometry, pore size distribution and network connectivity are the key control factors of stone and mortar deterioration.

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This paper presents the measurements of bulk density, matrix density, total open porosity, water absorption coefficient, water vapor diffusion resistance factor and thermal conductivity of hydrophilic mineral wool Front — Rock Max E. Front — Rock Max E consisted of two layers fasten together, namely a low-density and high-density layer.

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