Cathy Ridgway - Academia.edu (original) (raw)
Papers by Cathy Ridgway
Journal of Pulp and Paper Science Vol.35 Nr.3-4, 137-147 The aim of this work is to clarify the c... more Journal of Pulp and Paper Science Vol.35 Nr.3-4, 137-147 The aim of this work is to clarify the controlling role of polyvinyl alcohol (PVOH) as a binder in the formation of coating and pore structure and how it affects the high-speed inkjet image quality formation. The results show that the pigment type and the binder amount have a large interactive effect on pore structure formation. The optical properties of the whole paper, not just the coating, are the most important regarding print density, but the properties of the coating layer itself have a dominant effect when considering the ink bleeding. The aim of this work is to clarify the controlling role of polyvinyl alcohol (PVOH) as a binder in the formation of coating and pore structure and how it affects the high-speed inkjet image quality formation. The results show that the pigment type and the binder amount have a large interactive effect on pore structure formation. The optical properties of the whole paper, not just the coat...
TAPPI 11th Advanced Coating Fundamentals Symposium: The Latest Advances in Coating Research and D... more TAPPI 11th Advanced Coating Fundamentals Symposium: The Latest Advances in Coating Research and Development. Munich, Germany, 11-13 Oct. 2010, 195-214 Inkjet coatings usually contain specialty pigments with a high specific surface area and binders which provide high binding force. The final coating structure has a high pore volume and it contains a high frequency of fine diameter pores together with large pore volume capacity. During the inkjet ink absorption process, the capillary and permeation flow drives the liquid into the coating structure and controls volume flow, respectively. However, the role of diffusion within the timescale of the inkjet ink imbibition process has not been studied widely. The aim of this work is to clarify the interactive role of the porous structure and the coexistent swelling of binder during the liquid imbibition, with special attention to the fixation of dye and its distribution. The impact of polarity of the vehicle was studied using compressed pigm...
Powder Technology, 1995
A void space network is presented for the simulation of mercury intrusion and the calculation of ... more A void space network is presented for the simulation of mercury intrusion and the calculation of the absolute permeability of porous media. Mercury intrusion is simulated by the Laplace/Washburn equation within a percolation algorithm. A 'Dinic' operational research network analysis algorithm gives the maximal flow capacity of the unit ceil. A combination of the Darcy and Poiseuille equations of flow is then used to derive the absolute gas permeability of the simulated structure. Mercury intrusion curves and permeabilities are calculated for networks with banding, clustering of small pores and throats, or clustering of large pores and throats. The modelling method is then applied to banded sandstone samples with edge corrections, and it is shown that the constraint of fitting to experimental mercury intrusion data suppresses the permeability differences induced by structural changes alone. The same networks can model mercury hysteresis, porosity, connectivity, pore/throat size correlation, tortuosity and other properties, and can be applied to any consolidated porous medium.
Results of simulated supersource imbibition into model network structures are compared with exper... more Results of simulated supersource imbibition into model network structures are compared with experimental observations of real network structures determined by dynamical gravimetric fluid uptake. A computer model, Pore-Cor, has been used previously to simulate the imbibition of fluid into porous structures by applying an imbibition algorithm for fluids undergoing both inertial and viscous dynamical absorption (Schoelkopf et al., 2000). The
Five samples of fine particle size calcium carbonate, typically used as excipient or as active ph... more Five samples of fine particle size calcium carbonate, typically used as excipient or as active pharma ingredient (API): a powder, two granulated samples (compressible precursor) and two tablet samples, were analysed to establish the pore size distribution within their packed structures. Three different measurement techniques have been used to characterise the samples, mercury porosimetry, hexadecane imbibition and hexadecane permeability. The structures have also been modelled using the Pore-Cor network simulator. The effective pore size distribution and its origin are used to demonstrate the impact of particle size distribution of the starting material powder in order to create denser tablets and hence smaller, more easily swallowable tablet forms. The application of the network simulator illustrates the importance of taking account of pore shielding when describing potential solutions to liquid uptake and dissolution dynamics of the end product in drug delivery. The work shows that ground calcium carbonate, with its close to log-normal particle size distribution, provides an improved packing, in comparison to typical monosize precipitated calcium carbonate, under tablet-forming conditions with well-defined absorption and permeation properties.
Transport in Porous Media, 2006
Porous media with rapid absorption properties are greatly sought after in the fields of super abs... more Porous media with rapid absorption properties are greatly sought after in the fields of super absorbers and catalysts. Natural materials, such as diatomite, or synthetic zeolite feature strongly in industrial reaction processes. Most, or all, of such materials, however, are surface acidic. A novel rapidly absorbing alkaline porous structure, with a high absorption capacity, is presented here. As in the case of diatomite or zeolite, the pigment design incorporates strong capillarity within a highly permeable packed medium. A model is proposed for general use with highly absorbing media that can be proven microscopically to have separate domains of micro- or nano-capillarity embedded within a permeable matrix. The new pigment morphology, based on natural ground calcium carbonate (gcc), exhibits this property using special surface structure modifications. It is contrasted with standard gcc by using consolidated tablet blocks made from a suspension of the pigment and chosen mixtures thereof. The blocks are characterised after drying by mercury porosimetry, and the absorption dynamic of a selected liquid is studied. It is shown that using a self-assembly method of discrete pore structures provides a much faster absorption rate and a liquid capacity for up to 10 times more fluid than a conventional homogeneously distributed pore concept. In such unique discrete network systems, the mercury intrusion curve provides a separable analysis of permeability and capillarity in respect to the inflection point of the cumulative intrusion curve. The discrete decoupled properties each follow the absorption behaviour predicted by previous modelling (Ridgway and Gane, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 206(1–3), 2002). The absorption driving force is shown to be determined by the proportion of fine pores present up to a size equal to a Bosanquet inertially-defined optimum within the timescale of absorption. Combining the wetting force, from the capillarity-controlled fine pore structure, with the experimental flow resistance of the sample, consisting of the assembly of particles, it is possible to predict the trends in absorption dynamic using the pore and throat model Pore-Cor.* Use of this model allows existing materials as well as new synthetic designs to be modelled prior to manufacture. The novel alkaline material is compared with independent absorption data for diatomite and shown to be comparable.
The purpose of this study was to investigate whether a previously developed computer model, named... more The purpose of this study was to investigate whether a previously developed computer model, named Pore-Cor, could simulate the subtle changes in void space dimensions which occur during the artificial deposition of small amounts of illite and kaolinite within Fontainebleau sandstone. Clay precipitation was carried out by placing a sandstone plug in a gold capsule, with an alu- minosilicate gel,
JAPAN TAPPI JOURNAL, 2009
Transport in Porous Media, 1997
In previous works, we have described a void space reconstruction method based on non-wetting flui... more In previous works, we have described a void space reconstruction method based on non-wetting fluid intrusion, wetting fluid drainage, and image analysis data. The method has been applied to a wide range of substances, including sandstone, compressed and sintered powders, paper substrates and coatings, soil and fibrous mats. We have also demonstrated in a previous work that the spatial correlation
Transport in Porous Media, 2014
ABSTRACT Considering the separable phenomena of imbibition in complex fine porous media as a func... more ABSTRACT Considering the separable phenomena of imbibition in complex fine porous media as a function of timescale, it is noted that there are two discrete imbibition rate regimes when expressed in the Lucas–Washburn (L–W) equation. Commonly, to account for this deviation from the single equivalent hydraulic capillary, experimentalists propose an effective contact angle change. In this work, we consider rather the general term of the Wilhelmy wetting force regarding the wetting line length, and apply a proposed increase in the liquid–solid contact line and wetting force provided by the introduction of surface meso/nanoscale structure to the pore wall roughness. An experimental surface pore wall feature size regarding the rugosity area is determined by means of capillary condensation during nitrogen gas sorption in a ground calcium carbonate tablet compact. On this nano size scale, a fractal structure of pore wall is proposed to characterize for the internal rugosity of the porous medium. Comparative models based on the Lucas–Washburn and Bosanquet inertial absorption equations, respectively, for the short timescale imbibition are constructed by applying the extended wetting line length and wetting force to the equivalent hydraulic capillary observed at the long timescale imbibition. The results comparing the models adopting the fractal structure with experimental imbibition rate suggest that the L–W equation at the short timescale cannot match experiment, but that the inertial plug flow in the Bosanquet equation matches the experimental results very well. If the fractal structure can be supported in nature, then this stresses the role of the inertial term in the initial stage of imbibition. Relaxation to a smooth-walled capillary then takes place over the longer timescale as the surface rugosity wetting is overwhelmed by the pore condensation and film flow of the liquid ahead of the bulk wetting front, and thus to a smooth walled capillary undergoing permeation viscosity-controlled flow.
Transport in Porous Media, 2014
Nano and microfibrillated cellulose (NFC and MFC, respectively, collectively termed MNFC) is know... more Nano and microfibrillated cellulose (NFC and MFC, respectively, collectively termed MNFC) is known to interact strongly with water, related to its high polarity and surface area. The swelling behaviour acts to form a gel with high water retention properties. The observation that nanocellulose could possibly be used in paper or other coating formulations, as a co-binder, for example, raises a question about the possible effects it could have on coating pore structure. In this study, we analyse the pore structure of pigmented coatings, liquid absorption and permeability, in respect to the influence of partially substituting traditional co-binder carboxymethyl cellulose with MNFC. The contrast between polar water and nonpolar liquid, such as alkane, is used to probe the water interactive and extractable in-coating (internal) gel-formation properties of the nanocellulosic materials. These contrasting liquids are important in many processes, such as offset printing, but also in respect to exposure of coatings in general to environmental factors in application. Results show that permeability to liquid water is dramatically reduced when nanocellulosic material is present, though water can permeate by diffusion through the nanocellulose gel network. Long timescale exposure to water during absorption leads to extraction of any soluble salts remaining after the chemical treatment of the fibrillar material during production. Inert alkane, on the other hand, can absorb and permeate freely without interactive hindrance from the nanocellulose, with no extractive effect. Such a construct could in principle be considered for use as an oil-water differential membrane or for slow release concepts in aqueous systems by loading soluble deliverable materials within the nanocellulosic gel.
Transport in Porous Media, 2011
Fine calcium carbonate is frequently used as coating pigment, e.g. in paints, paper and board. Em... more Fine calcium carbonate is frequently used as coating pigment, e.g. in paints, paper and board. Emulsion polymer latex provides a typical binder incorporated in such coatings. Exposure of the resulting porous structure to liquid, depending on latex concentration level, results in ab-and adsorption as the liquid is drawn into the structure by capillarity and the nature of the relative surface chemistry of the pores. Previous work has shown that typical coating structures act to separate oil components according to their surface energy characteristics and solubility index in respect to pigment surface and intra-latex diffusion. This study considers water and alkane (hexadecane) as model liquids. Absorption rate into compressed tablets of ground calcium carbonate is observed with and without the presence of latex. Polyacrylate dispersant used in manufacture renders the pigment surface both hydrophilic and hygroscopic and, therefore, controls the differential dynamic wetting characteristics of the porous structure for either polar or non-polar liquid. In competition with hexadecane saturating the pore structure of a latex-free sample, polar water is seen to displace the non-polar liquid instantaneously, causing disintegration of the packed porous structure. In the presence of latex binder, however, the structurally destructive pressure this creates is contained, and retardation of the polar water is observed. The required pre-wetting action of water vapour diffusion on the polyacrylate pigment surface is considered to be an integral part of the successful competition between oil and water in the offset printing process, as non-polar oil absorbs steadily into a water pre-saturated structure.
Transport in Porous Media, 2007
An algorithm has been developed for the calculation of the size of the effective structural or sk... more An algorithm has been developed for the calculation of the size of the effective structural or skeletal elements which make up the solid phase of an unconsolidated or consolidated porous block. It is based on a previously presented algorithm, but it has now been validated on unconsolidated samples and tested on consolidated samples. It also includes a virtual reality representation of the structures. First, a network model named Pore-Cor is made to reproduce the percolation behaviour of the experimental sample, by matching its simulated percolation characteristics to an experimental mercury intrusion curve. The algorithm then grows skeletal elements between the cubic pores and cylindrical throats of the void network model until they touch up to four of the adjacent void features. The size distributions of the simulated solid elements are compared with each other and with experimentally determined particle size distributions, using a Mann-Whitney test. The algorithm was shown to simulate skeletal elements with the correct trends in size distribution for two different sand samples, provided the sand packed itself optimally under the applied mercury pressure. It was also applied to two samples of variously compressed calcium carbonate powder, having fine and coarse particle size distributions respectively. The simulation demonstrated that on compressing the powder at the minimum force, the skeletal elements differed from the constituent particle sizes, as expected. The average size of the skeletal elements increased as the compression force was increased on
Transport in Porous Media, 2006
Abstract Two different porous building materials have been previously measured and analysed (El-A... more Abstract Two different porous building materials have been previously measured and analysed (El-Abd and Milczarek, 2004, IEEE Trans. Nuclear Sci.; El-Abd et al., 2004, J. Phys. D) using neutron radiography to measure the water front position over time. The results ...
Journal of Pulp and Paper Science Vol.35 Nr.3-4, 137-147 The aim of this work is to clarify the c... more Journal of Pulp and Paper Science Vol.35 Nr.3-4, 137-147 The aim of this work is to clarify the controlling role of polyvinyl alcohol (PVOH) as a binder in the formation of coating and pore structure and how it affects the high-speed inkjet image quality formation. The results show that the pigment type and the binder amount have a large interactive effect on pore structure formation. The optical properties of the whole paper, not just the coating, are the most important regarding print density, but the properties of the coating layer itself have a dominant effect when considering the ink bleeding. The aim of this work is to clarify the controlling role of polyvinyl alcohol (PVOH) as a binder in the formation of coating and pore structure and how it affects the high-speed inkjet image quality formation. The results show that the pigment type and the binder amount have a large interactive effect on pore structure formation. The optical properties of the whole paper, not just the coat...
TAPPI 11th Advanced Coating Fundamentals Symposium: The Latest Advances in Coating Research and D... more TAPPI 11th Advanced Coating Fundamentals Symposium: The Latest Advances in Coating Research and Development. Munich, Germany, 11-13 Oct. 2010, 195-214 Inkjet coatings usually contain specialty pigments with a high specific surface area and binders which provide high binding force. The final coating structure has a high pore volume and it contains a high frequency of fine diameter pores together with large pore volume capacity. During the inkjet ink absorption process, the capillary and permeation flow drives the liquid into the coating structure and controls volume flow, respectively. However, the role of diffusion within the timescale of the inkjet ink imbibition process has not been studied widely. The aim of this work is to clarify the interactive role of the porous structure and the coexistent swelling of binder during the liquid imbibition, with special attention to the fixation of dye and its distribution. The impact of polarity of the vehicle was studied using compressed pigm...
Powder Technology, 1995
A void space network is presented for the simulation of mercury intrusion and the calculation of ... more A void space network is presented for the simulation of mercury intrusion and the calculation of the absolute permeability of porous media. Mercury intrusion is simulated by the Laplace/Washburn equation within a percolation algorithm. A 'Dinic' operational research network analysis algorithm gives the maximal flow capacity of the unit ceil. A combination of the Darcy and Poiseuille equations of flow is then used to derive the absolute gas permeability of the simulated structure. Mercury intrusion curves and permeabilities are calculated for networks with banding, clustering of small pores and throats, or clustering of large pores and throats. The modelling method is then applied to banded sandstone samples with edge corrections, and it is shown that the constraint of fitting to experimental mercury intrusion data suppresses the permeability differences induced by structural changes alone. The same networks can model mercury hysteresis, porosity, connectivity, pore/throat size correlation, tortuosity and other properties, and can be applied to any consolidated porous medium.
Results of simulated supersource imbibition into model network structures are compared with exper... more Results of simulated supersource imbibition into model network structures are compared with experimental observations of real network structures determined by dynamical gravimetric fluid uptake. A computer model, Pore-Cor, has been used previously to simulate the imbibition of fluid into porous structures by applying an imbibition algorithm for fluids undergoing both inertial and viscous dynamical absorption (Schoelkopf et al., 2000). The
Five samples of fine particle size calcium carbonate, typically used as excipient or as active ph... more Five samples of fine particle size calcium carbonate, typically used as excipient or as active pharma ingredient (API): a powder, two granulated samples (compressible precursor) and two tablet samples, were analysed to establish the pore size distribution within their packed structures. Three different measurement techniques have been used to characterise the samples, mercury porosimetry, hexadecane imbibition and hexadecane permeability. The structures have also been modelled using the Pore-Cor network simulator. The effective pore size distribution and its origin are used to demonstrate the impact of particle size distribution of the starting material powder in order to create denser tablets and hence smaller, more easily swallowable tablet forms. The application of the network simulator illustrates the importance of taking account of pore shielding when describing potential solutions to liquid uptake and dissolution dynamics of the end product in drug delivery. The work shows that ground calcium carbonate, with its close to log-normal particle size distribution, provides an improved packing, in comparison to typical monosize precipitated calcium carbonate, under tablet-forming conditions with well-defined absorption and permeation properties.
Transport in Porous Media, 2006
Porous media with rapid absorption properties are greatly sought after in the fields of super abs... more Porous media with rapid absorption properties are greatly sought after in the fields of super absorbers and catalysts. Natural materials, such as diatomite, or synthetic zeolite feature strongly in industrial reaction processes. Most, or all, of such materials, however, are surface acidic. A novel rapidly absorbing alkaline porous structure, with a high absorption capacity, is presented here. As in the case of diatomite or zeolite, the pigment design incorporates strong capillarity within a highly permeable packed medium. A model is proposed for general use with highly absorbing media that can be proven microscopically to have separate domains of micro- or nano-capillarity embedded within a permeable matrix. The new pigment morphology, based on natural ground calcium carbonate (gcc), exhibits this property using special surface structure modifications. It is contrasted with standard gcc by using consolidated tablet blocks made from a suspension of the pigment and chosen mixtures thereof. The blocks are characterised after drying by mercury porosimetry, and the absorption dynamic of a selected liquid is studied. It is shown that using a self-assembly method of discrete pore structures provides a much faster absorption rate and a liquid capacity for up to 10 times more fluid than a conventional homogeneously distributed pore concept. In such unique discrete network systems, the mercury intrusion curve provides a separable analysis of permeability and capillarity in respect to the inflection point of the cumulative intrusion curve. The discrete decoupled properties each follow the absorption behaviour predicted by previous modelling (Ridgway and Gane, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 206(1–3), 2002). The absorption driving force is shown to be determined by the proportion of fine pores present up to a size equal to a Bosanquet inertially-defined optimum within the timescale of absorption. Combining the wetting force, from the capillarity-controlled fine pore structure, with the experimental flow resistance of the sample, consisting of the assembly of particles, it is possible to predict the trends in absorption dynamic using the pore and throat model Pore-Cor.* Use of this model allows existing materials as well as new synthetic designs to be modelled prior to manufacture. The novel alkaline material is compared with independent absorption data for diatomite and shown to be comparable.
The purpose of this study was to investigate whether a previously developed computer model, named... more The purpose of this study was to investigate whether a previously developed computer model, named Pore-Cor, could simulate the subtle changes in void space dimensions which occur during the artificial deposition of small amounts of illite and kaolinite within Fontainebleau sandstone. Clay precipitation was carried out by placing a sandstone plug in a gold capsule, with an alu- minosilicate gel,
JAPAN TAPPI JOURNAL, 2009
Transport in Porous Media, 1997
In previous works, we have described a void space reconstruction method based on non-wetting flui... more In previous works, we have described a void space reconstruction method based on non-wetting fluid intrusion, wetting fluid drainage, and image analysis data. The method has been applied to a wide range of substances, including sandstone, compressed and sintered powders, paper substrates and coatings, soil and fibrous mats. We have also demonstrated in a previous work that the spatial correlation
Transport in Porous Media, 2014
ABSTRACT Considering the separable phenomena of imbibition in complex fine porous media as a func... more ABSTRACT Considering the separable phenomena of imbibition in complex fine porous media as a function of timescale, it is noted that there are two discrete imbibition rate regimes when expressed in the Lucas–Washburn (L–W) equation. Commonly, to account for this deviation from the single equivalent hydraulic capillary, experimentalists propose an effective contact angle change. In this work, we consider rather the general term of the Wilhelmy wetting force regarding the wetting line length, and apply a proposed increase in the liquid–solid contact line and wetting force provided by the introduction of surface meso/nanoscale structure to the pore wall roughness. An experimental surface pore wall feature size regarding the rugosity area is determined by means of capillary condensation during nitrogen gas sorption in a ground calcium carbonate tablet compact. On this nano size scale, a fractal structure of pore wall is proposed to characterize for the internal rugosity of the porous medium. Comparative models based on the Lucas–Washburn and Bosanquet inertial absorption equations, respectively, for the short timescale imbibition are constructed by applying the extended wetting line length and wetting force to the equivalent hydraulic capillary observed at the long timescale imbibition. The results comparing the models adopting the fractal structure with experimental imbibition rate suggest that the L–W equation at the short timescale cannot match experiment, but that the inertial plug flow in the Bosanquet equation matches the experimental results very well. If the fractal structure can be supported in nature, then this stresses the role of the inertial term in the initial stage of imbibition. Relaxation to a smooth-walled capillary then takes place over the longer timescale as the surface rugosity wetting is overwhelmed by the pore condensation and film flow of the liquid ahead of the bulk wetting front, and thus to a smooth walled capillary undergoing permeation viscosity-controlled flow.
Transport in Porous Media, 2014
Nano and microfibrillated cellulose (NFC and MFC, respectively, collectively termed MNFC) is know... more Nano and microfibrillated cellulose (NFC and MFC, respectively, collectively termed MNFC) is known to interact strongly with water, related to its high polarity and surface area. The swelling behaviour acts to form a gel with high water retention properties. The observation that nanocellulose could possibly be used in paper or other coating formulations, as a co-binder, for example, raises a question about the possible effects it could have on coating pore structure. In this study, we analyse the pore structure of pigmented coatings, liquid absorption and permeability, in respect to the influence of partially substituting traditional co-binder carboxymethyl cellulose with MNFC. The contrast between polar water and nonpolar liquid, such as alkane, is used to probe the water interactive and extractable in-coating (internal) gel-formation properties of the nanocellulosic materials. These contrasting liquids are important in many processes, such as offset printing, but also in respect to exposure of coatings in general to environmental factors in application. Results show that permeability to liquid water is dramatically reduced when nanocellulosic material is present, though water can permeate by diffusion through the nanocellulose gel network. Long timescale exposure to water during absorption leads to extraction of any soluble salts remaining after the chemical treatment of the fibrillar material during production. Inert alkane, on the other hand, can absorb and permeate freely without interactive hindrance from the nanocellulose, with no extractive effect. Such a construct could in principle be considered for use as an oil-water differential membrane or for slow release concepts in aqueous systems by loading soluble deliverable materials within the nanocellulosic gel.
Transport in Porous Media, 2011
Fine calcium carbonate is frequently used as coating pigment, e.g. in paints, paper and board. Em... more Fine calcium carbonate is frequently used as coating pigment, e.g. in paints, paper and board. Emulsion polymer latex provides a typical binder incorporated in such coatings. Exposure of the resulting porous structure to liquid, depending on latex concentration level, results in ab-and adsorption as the liquid is drawn into the structure by capillarity and the nature of the relative surface chemistry of the pores. Previous work has shown that typical coating structures act to separate oil components according to their surface energy characteristics and solubility index in respect to pigment surface and intra-latex diffusion. This study considers water and alkane (hexadecane) as model liquids. Absorption rate into compressed tablets of ground calcium carbonate is observed with and without the presence of latex. Polyacrylate dispersant used in manufacture renders the pigment surface both hydrophilic and hygroscopic and, therefore, controls the differential dynamic wetting characteristics of the porous structure for either polar or non-polar liquid. In competition with hexadecane saturating the pore structure of a latex-free sample, polar water is seen to displace the non-polar liquid instantaneously, causing disintegration of the packed porous structure. In the presence of latex binder, however, the structurally destructive pressure this creates is contained, and retardation of the polar water is observed. The required pre-wetting action of water vapour diffusion on the polyacrylate pigment surface is considered to be an integral part of the successful competition between oil and water in the offset printing process, as non-polar oil absorbs steadily into a water pre-saturated structure.
Transport in Porous Media, 2007
An algorithm has been developed for the calculation of the size of the effective structural or sk... more An algorithm has been developed for the calculation of the size of the effective structural or skeletal elements which make up the solid phase of an unconsolidated or consolidated porous block. It is based on a previously presented algorithm, but it has now been validated on unconsolidated samples and tested on consolidated samples. It also includes a virtual reality representation of the structures. First, a network model named Pore-Cor is made to reproduce the percolation behaviour of the experimental sample, by matching its simulated percolation characteristics to an experimental mercury intrusion curve. The algorithm then grows skeletal elements between the cubic pores and cylindrical throats of the void network model until they touch up to four of the adjacent void features. The size distributions of the simulated solid elements are compared with each other and with experimentally determined particle size distributions, using a Mann-Whitney test. The algorithm was shown to simulate skeletal elements with the correct trends in size distribution for two different sand samples, provided the sand packed itself optimally under the applied mercury pressure. It was also applied to two samples of variously compressed calcium carbonate powder, having fine and coarse particle size distributions respectively. The simulation demonstrated that on compressing the powder at the minimum force, the skeletal elements differed from the constituent particle sizes, as expected. The average size of the skeletal elements increased as the compression force was increased on
Transport in Porous Media, 2006
Abstract Two different porous building materials have been previously measured and analysed (El-A... more Abstract Two different porous building materials have been previously measured and analysed (El-Abd and Milczarek, 2004, IEEE Trans. Nuclear Sci.; El-Abd et al., 2004, J. Phys. D) using neutron radiography to measure the water front position over time. The results ...