3D X-ray Microtomography Research Articles

Effect of Particle Breakage of Sand Under High Oedometric Stress on its Microstructural Properties Using 3D X-ray Micro-tomography

Effect of Particle Breakage of Sand Under High Oedometric Stress on its Microstructural Properties Using 3D X-ray Micro-tomography

Bulk characterization of highly structured tissue paper based on 2D and 3D evaluation methods

The structure of the fibre network in tissue paper can be complex and difficult to analyze, due to the presence of superimposed structures such as creping and patterns that occur, for example, in through-air-dried (TAD) tissue. Properties like high absorbency, a pleasant handfeel, and strength-related characteristics are closely related to the fibre network structure. Therefore, in addition to standard tissue testing methods, techniques that provide insights into the intrinsic properties of the tissue fibre network are essential for a deeper understanding and potential for further optimization. In this study, we utilized 2D cross-sectional images and 3D X-ray microtomography (mu-CT) to evaluate and quantify the intrinsic properties of highly structured TAD tissue. We compared the results obtained from these two methods, focusing on intrinsic thickness, porosity, and the fibre volume to fibre surface area (Fv/Fs) ratio. The open structure of the fibre network, fabric patterns, creping, and protruding fibres make it challenging to define bulk boundaries. Therefore, we examined the effect of different bulk expansion diameters on intrinsic properties. This procedure allows to quantify the effects of under- and overestimation of bulk boundaries, and to determine which regions within the fibre network are affected by bulk expansion. In terms of intrinsic thickness, both 2D and 3D evaluations show similar trends, which facilitates direct comparison of 2D and 3D data. Porosity, on the other hand, does not show any correlation between 2D and 3D-based data. Together with the Fv/Fs parameter, this leads to the conclusion that the depiction of 2D data does not represent the whole fibrous material but predominantly fibres perpendicular or close to perpendicular to the cut plane, whereas 3D data represents all fibres, fibre bonds and network connectivity. This work aims at presenting modern approaches and novel procedures to quantify intrinsic properties of open fibre structures such as tissue, but could also be applied to fibrous networks in general. The introduced methods could provide the basis for future research on the interrelations between intrinsic properties and key tissue properties such as absorbency and handfeel.

Pore-scale characterization of residual gas remobilization in CO2 geological storage

A decrease in reservoir pressure can lead to remobilization of residually trapped CO2. In this study, the pore-scale processes related to trapped CO2 remobilization under pressure depletion were investigated with the use of high-resolution 3D X-ray microtomography. The distribution of CO2 in the pore space of Bentheimer sandstone was measured after waterflooding at a fluid pressure of 10 MPa, and then at pressures of 8, 6 and 5 MPa. At each stage CO2 was produced, implying that swelling of the gas phase and exsolution allowed the gas to reconnect and flow. After production, the gas reached a new position of equilibrium where it may be trapped again. At the end of the experiment, we imaged the sample again after 30 hours. Firstly, the results showed that an increase in saturation beyond the residual value was required to remobilize the gas, which is consistent with earlier field-scale results. Additionally, Ostwald ripening and continuing exsolution lead to a significant change in fluid saturation: transport of dissolved gas in the aqueous phase to equilibriate capillary pressure led to reconnection of the gas and its flow upwards under gravity. The implications for CO2 storage are discussed: an increase in saturation beyond the residual value is required to mobilize the gas, but Ostwald ripening can allow local reconnection of hitherto trapped gas, thus enhancing migration and may reduce the amount of CO2 that can be capillary trapped in storage operations.

High rate, high temperature, dendrite free plating/stripping of Li in 3-dimensional honeycomb boron carbon nitride to realize an ultrastable lithium metal anode

Lithium (Li) metal could be the anode of choice for energy dense Li-batteries owing to its high theoretical specific capacity. However, low coulombic efficiency and poor safety on account of the occurrence of the Li-dendrites during charging-discharging pose a bottleneck for practical applications. In this work, we report a high-rate plating and stripping of Li through host engineering to realize ultrastable Li metal anode (LMA). Benchmark plating/stripping efficiency could be achieved via uniquely structured, highly ordered honeycomb boron carbon nitride (HBCN) as a functional scaffold. Boron and nitrogen doping, large surface area and ordered mesoporous structure induce homogeneous solid electrolyte interface (SEI) layer formation and provide numerous nucleation sites with subsequent dendrite-free growth with 99.98 % coulombic efficiency at 8 mA cm−2 high current and 10 mAh cm−2 capacity over 3000 cycles. Via post-cycling advanced characterizations techniques of Ex-situ XPS, 3D X-ray micro-tomography analyses and FESEM, we demonstrate the formation of a stable SEI layer and morphological changes that occurred during Li plating cycles in the HBCN structure. Computational studies validate the high lithium plating-stripping efficacy of HBCN to its highly ordered porous nature, exothermic Li-binding and upshift in the Fermi levels. When tested at elevated temperature (50 °C), a stable Li plating-stripping in HBCN is realised at 4 mA cm−2 current and 10 mAh cm−2 capacity values with ∼100 % C.E.Furthermore, we report the results of testing a Li metal cell comprised of Li deposited HBCN anode and LiFePO4 (LFP) cathode.

Visual acuity of Empoasca onukii (Hemiptera, Cicadellidae)

Empoasca onukii is a common tea plant pest with a preference for the color yellow. Past work has shown that host leaf color is a key cue for habitat location for E. onukii. Before studying the effect of foliage shape, size, or texture on habitat localization, it is necessary to determine the visual acuity and effective viewing distance of E. onukii. In this study, a combination of 3D microscopy and X-ray microtomography showed that visual acuity did not significantly differ between females and males, but there were significant differences in the visual acuity and optical sensitivity among five regions of E. onukii's compound eyes. The dorsal ommatidia had the highest visual acuity at 0.28 cycles per degree (cpd) but the lowest optical sensitivity (0.02 μm2sr), which indicated a trade-off between visual resolution and optical sensitivity for E. onukii. The visual acuity determined from the behavioral experiment was 0.14 cpd; E. onukii exhibited low-resolution vision and could only distinguish the units in a yellow/red pattern within 30 cm. Therefore, visual acuity contributes to the limited ability of E. onukii to distinguish the visual details of a distant target, which might be perceived as a lump of blurred color of intermediate brightness.

Designing Solvated Double-Layer Polymer Electrolytes with Molecular Interactions Mediated Stable Interfaces for Sodium Ion Batteries.

Unstable cathode-electrolyte and/or anode-electrolyte interface in polymer-based sodium-ion batteries (SIBs) will deteriorate their cycle performance. Herein, a unique solvated double-layer quasi-solid polymer electrolyte (SDL-QSPE) with high Na+ ion conductivity is designed to simultaneously improve stability on both cathode and anode sides. Different functional fillers are solvated with plasticizers to improve Na+ conductivity and thermal stability. The SDL-QSPE is laminated by cathode- and anode-facing polymer electrolyte to meet the independent interfacial requirements of the two electrodes. The interfacial evolution is elucidated by theoretical calculations and 3D X-ray microtomography analysis. The Na0.67 Mn2/3 Ni1/3 O2 |SDL-QSPE|Na batteries exhibit 80.4 mAh g-1 after 400 cycles at 1 C with the Coulombic efficiency close to 100 %, which significantly outperforms those batteries using the monolayer-structured QSPE.

X-ray micro-tomographic imaging and modelling of saline ice properties in concrete frost salt scaling experiments

Frost salt scaling of concrete is related to cyclic freezing and melting of a few millimeter thick deicer solution on the surface of the concrete. It is almost absent when pure water is freezing and reaches a maximum at a so-called pessimum concentration that for NaCl is around 3%. Different mechanisms have been suggested to explain this pessimum and frost salt scaling in general, ranging from the transport of moisture and growth of ice within the pore space of concrete (“cryogenic suction”) to crack formation in the saline ice layer followed by spalling off the surface (“glue-spall”). Though in these theories the saline ice layer, that forms in concrete frost salt scaling experiments, plays a major role, so far little is known about its properties. We present a characterisation and an analysis of the microstructure of this saline ice layer by means of 3D X-ray microtomography. We found that the morphology of the saline ice is very similar to young, columnar sea ice, with lamellae of ice and brine oriented in the direction of freezing. On the basis of the microscopic 3D image data, we formulated percolation-based models of macroscopic properties (e.g., strength, thermal expansion coefficient, porosity metrics) relevant for different proposed frost salt scaling mechanisms. Model results and observations suggest that the ice growth velocity, direction and confinement, have a major impact on the pore structure of saline ice, thereby governing both mechanical and transport properties. These properties in turn are expected to affect proposed frost salt scaling mechanisms of concrete. The microstructure length scales in the ice-brine composite (lamellar spacing, pore width) are comparable to those for concrete (air void spacing and size), suggesting complex poro-mechanical interaction at the interface of concrete and saline ice. The results highlight the importance of studying saline ice properties to improve predictions of frost salt scaling processes.

Pre-Sowing Treatments, Seed Components and Water Imbibition Aids Seed Germination of Gloriosa superba

Gloriosa superba L. is a horticulturally and medicinally important plant. Its seeds have poor, erratic, and deferred germination. The detailed seed structure components and water imbibition mechanism facilitating the process of seed germination in G. superba remain unexplored. Therefore, it is essential to develop methods to ensure consistent and enhanced seed germination in G. superba. Various pre-sowing treatments along with the Brunauer-Emmett-Teller (BET) surface area analysis and 3D X-ray micro-tomography (micro-T) were employed to elucidate seed structure components, porosity network, and the water imbibition mechanism during germination in G. superba. The study revealed that consistent and significantly improved seed germination (>85%) was observed using the pre-sowing treatment mechanical scarification followed by 24 h water soaking in G. superba. BET and micro-T showed that the tegmen of the seed coat exhibited porosity (21%) with a well-connected porosity network (17.50%) that helped in water movement through hilum, which was confirmed by phosphotungstic acid staining. However, the sarcotesta and endosperm were water-impermeable due to their negligible porosity. Multidisciplinary techniques such as BET and micro-T along with conventional methodologies can be employed to address the seed coat structure, porosity, and water imbibition mechanism aiding seed germination. Mechanical scarification enabled the water to penetrate internal seed layers through the permeable tegmen via the reticulate pore network, which significantly improved seed germination. The developed seed germination method can produce a large number of plants in less time and conserve the natural populations of this high-value medicinally important species.

A numerical study of pore formation mechanisms in aluminium cold spray coatings

Porosity is critical regarding cold sprayed coatings properties: it can be an asset for certain applications as in tribology, it is generally at the cost of mechanical and anti-corrosion properties. It is thus important to understand the mechanisms at its origin, in order to have a better control over it. Since the build-up process of a cold spray coating cannot be directly observed at a microscopic scale, numerical simulation is the only way to address the mechanisms of pore formation. The main purpose of this study is to understand by dedicated simulations the mechanisms, acting during the build-up of a cold spray coating, giving rise to pore formation mechanisms. Besides, an user-independent method developed to assess porosity from these simulations is presented. The first part of the study, analysing the results of a 500 particles impact simulation, shows that porosity is mainly caused by two intricate mechanisms: interfacial porosity is created by a geometrical effect at particle/particle interfaces, whereas stack porosity is caused by particle density variations in the gas flow. Then, an original method, based on the commutation of successive convex hulls, to estimate porosity from multi-particle impact simulations is presented. Initial particles position has a strong influence on this estimation and the reference volume to compute porosity must therefore be thoroughly chosen. Finally, porosity computed by numerical simulation are compared to 3D X-ray microtomography measurements. • Pore formation mechanisms in cold spray are numerically assessed. • The main mechanisms involve interface defects and stack up faults. • These mechanisms rationalize the formation of porous network, highlighted by X-ray microtomography. • A original user-independent method was developed to assess porosity level in simulated microstructure. • Porosity assessment in simulated microstructures is still a big challenge in cold spray.

Hollow Spherical Hierarchical MoO3/SiO2–TiO2 Structures for Photocatalytic Decomposition of Organic Pollutant in Water

In this study MoO3/TiO2–SiO2 layered spherical composites, having hierarchical structure, were synthesized on TOKEM-320Y anion exchanger template using by sol-gel methods. Properties of MoO3/TiO2–SiO2 composites were characterized by XRD, EDS, SEM, 3D X-ray microtomography, Raman, IR, DRS, BET, and PL techniques. The SEM, 3D X-ray microtomography and EDS analysis showed hollow spherical composites with diameters ranging from 200 to 400 μm with core/shell structure. The formation of TiO2–SiO2 shell on the MoO3 core results in lower oxygen vacancy concentrations in composite (0.0425) and a reduced bandgap width (2.56 eV in compare to 3.19 eV for MoO3 sample, which was analyzed through the UV–VIS DRS method). The performance of MoO3/TiO2–SiO2 composites was evaluated by photocatalytic degradation of methylene blue (MB) aqueous solution irradiated with an I2 excilamp (λmax = 312 nm). The photoabsorption energy properties of MoO3/TiO2–SiO2 composites are related to the interaction between TiO2–SiO2 and MoO3 which occurs through oxygen in Ti-O-Mo and Si-O-Mo. The MoO3/TiO2–SiO2 composites exhibited a much higher photocatalytic activity (rate constant is 0.0645 min‒1, degradation efficiency is 93% (20 min). This work demonstrates the relation between the formation of heterostructure in core/shell composite and its photocatalitic activity, providing fundamental guidance to improve photocatalytic performance of materials.

Influence of Porosity on Ultra-High Vacuum Gas-Tightness in Cold-Sprayed Aluminum Coatings

Vacuum chambers used in high-energy particle accelerator experiments are conventionally made of bulk beryllium, which shows significant drawbacks due to cost and toxicity. An alternative solution could be to develop chambers made of polymer-based composites. Since these materials exhibit high outgassing not compatible with an ultra-high vacuum environment, a suitable gas-tight coating is required. Cold spray deposition of aluminum can be a solution, provided that the coating behaves as a perfect vacuum barrier. Porosity, especially percolating porous networks, is key to coating gas tightness issues. This work addresses the relationship between porosity and gas-tightness in cold spray coatings. To do so, coatings with different porosity were achieved playing with powder morphology, composition, and process parameters. Their gas tightness was evaluated by helium leak tests. Classical microscopy, being essentially a 2D analysis, is strongly limited when dealing with 3D properties as porosity percolation. For this reason, 3D X-ray microtomography images of coatings were obtained and treated by image analysis methods: pores were compared in terms of size and shape. Overall porosity properties, including percolation and a homogeneity criterion, were also investigated. Percolating porosity was highlighted for several samples which showed poor gas-tightness properties. The permeability of percolating pore structures was then numerically computed by a fast Fourier transform-based method, to quantify the mass flow through the coating. Results of those computations were finally compared to experimental coating leak rate measurements, in an effort to elucidate the link between gas tightness and morphology of the pore space.

Hot cracking evolution and formation mechanism in 2195 Al-Li alloy printed by laser powder bed fusion

Al-Li alloys printed by laser powder bed fusion (LPBF) have huge potential for industrial application due to their remarkable advantages. However, the high hot cracking susceptibility (HCS) due to the addition of Li is still a key restraining factor for their rapid development towards such industrial application. Here in this report, hot cracking behaviour of 2195 Al-Li alloys fabricated by LPBF process was investigated by a three-dimensional (3D) X-ray micro-tomography technique. The relationship between the microstructural evolution and the high HCS was established to reveal the hot cracking mechanism for the first time. Observations by X-ray tomography showed large, interconnected cracks with a 3D reticular structure in the printed samples, extending layer by layer from the lamellar cracks in the previous single tracks along the building direction. Contributions to hot cracking were found to origin from the stable liquid film and the stress concentration. The segregation between the Al6CuLi3 and α-Al matrix contributed to the Al-Cu eutectics along the high-angle grain boundaries in form of intergranular liquid films. Furthermore, it was found that the interfacial layer (intradendritic liquid film) between the Al2Cu and the adjacent LiAlSi or AlCuMgAg exhibited the reduced micro-crack resistance in the interior of the grains. It was pointed out on the basis of the calculation that the higher stability of the intergranular liquid film led to a higher HCS at the grain boundaries as compared to that in the interior of the grains. Furthermore, high internal residual tensile stress provided the driving force for the crack initiation and propagation. In summary, this work contains a practical guide to optimize the powder composition and processing steps of high-quality Al-Li alloys produced by LPBF.

3D x-ray microtomography investigations on the bimodal porosity and high sulfur impregnation in 3D carbon foam for Li–S battery application

Lithium–sulfur (Li–S) batteries, regarded as one of the most promising alternatives to current state-of-the-art rechargeable Li-ion battery technologies, have received tremendous attention as potential candidates for next-generation portable electronics and the rapidly advancing electric vehicle market. However, substantial capacity decay, miserable cycle life, and meagre stability remain critical challenges. More specifically, shuttling of polysulfide (Li2S x (3 < x ⩽ 8)) species severely hinders the cycle performance resulting in capacity fade and cycling instability. In the present work, a highly conducting three-dimensional (3D) carbon nanofiber (CNF) foam has been synthesized using the lyophilization method followed by thermal pyrolysis. The highly porous foam materials have a bimodal porosity distribution in the nano and micro regime and were successfully investigated to serve as a potential host for sulfur species intended for Li–S battery application. 3D x-ray microtomography was employed to estimate the nature of sulfur impregnation and distribution in the 3D porous networks. On utilizing the final product as cathode material, sulfur impregnated carbonized CNF foam and modified the separator with functionalized multiwalled carbon nanotubes delivered a specific capacity of ∼845 mAh g−1 at 100 mA g−1.

Impact of the 3D morphology on the hygro-thermal transfer of hygroscopic materials: application to spruce wood

Spruce wood is a bio-based material that is well known in the building construction field because of its good thermal and acoustic properties. It has a heterogeneous anatomical structure and also hygroscopic nature which offers the possibility to swell or shrink–in accordance to–relative humidity solicitations. In this context, the aim of this paper is to investigate the influence of the microstructure of spruce wood on the mechanisms of heat and mass transfers. The novelty of this article is that a real 3D spruce wood structure is taken into account to model hygrothermal transfer within the material. A 3D X-ray micro-tomography was investigated for the reconstruction of the material at a resolution of 3.35 μm/pixel. Hygrothermal model was developed in order to predict the influence of the anatomical structure of wood on the material behaviour. The resulting 3D temperature and relative humidity profiles show a significant dependence on the morphological structure of the material and the mechanisms that are at the microscopic scale have an influence on the macroscopic scale.

Effect of autogenous shrinkage on microcracking and mass transport properties of concrete containing supplementary cementitious materials

It is well-known that supplementary cementitious materials (SCMs) and low water-to-binder (w/b) ratio increase autogenous shrinkage, but the impact on microcracking and long-term transport properties is less understood. This paper examines the effect of microcracking induced by autogenous shrinkage on transport properties of concretes cured up to ~3.6 years. Variables include SCM type (9% SF, 70% GGBS), w/b ratio (0.20–0.45), maximum-aggregate-size (MSA: 5–20 mm) and shrinkage reducing admixture (SRA). Oxygen diffusivity, permeability and water sorptivity were correlated with microcracks characterised using laser scanning confocal microscopy and 3D X-ray microtomography. Results show greater microcracking in mixes containing SCMs, low w/b ratio and large MSA. At the same w/b ratio and binder type, strong positive correlations are observed between transport and microcracking with increasing MSA, confirming the negative impact of autogenous shrinkage. SRA was effective in reducing these effects. The significance is compared with drying shrinkage and implications for durability are discussed.

Permeability of flax fibre mats: Numerical and theoretical prediction from 3D X-ray microtomography images

Flax fibre mats are promising and versatile biosourced reinforcements that can be used in composite parts obtained using various processing routes. To optimise their impregnation and the end-use properties of composites, it is crucial to better understand the process-induced evolution of their microstructure and their permeability. In this study, flax fibre mats were subjected to in situ X-ray microtomography compression experiments. The resulting 3D images enabled the evolution of several key descriptors of their microstructure under compression to be determined, and the evolution of their permeability to be quantified by direct fibre scale CFD simulations. The microstructural data were also used as input parameters of a modified directional Kozeny-Carman model, accounting for the anisotropy and heterogeneity of mats. Only one unknown directional parameter was identified by inverse method from permeability calculations performed on numerically generated 3D realistic fibre networks. The predictions of the proposed model were consistent with numerical simulations.

Mechanical and microstructural studies in a polysaccharide-acrylate double network hydrogel

Polymeric hydrogels continue to find a wide range of applications. However, a major drawback of hydrogels is the lack of mechanical strength. In this regard, “Double Network Hydrogels” (DN) have shown great promise recently. The toughness in DN hydrogels originates from the synergistic effect of two polymeric networks. In this work, we have synthesized a DN hydrogel consisting of a tightly cross linked carboxymethylcellulose (CMC) as the first network and loosely cross linked poly(hydroxyethylacrylate) (PHEA) as a second network (CMC-PHEA-DN). The required flexibility in the second network (PHEA) was induced by the presence of a small amount of stearyl methacrylate (SM) as a co-monomer in hydroxyl ethyl acrylate (HEA). The compressive strength of the CMC-PEHA-DN hydrogel was found to be 280 times more than that of CMC-SN hydrogel, and the presence of SM in DN hydrogels showed better recovery after deformation. Cell viability studies showed the biocompatibility of DN hydrogels. The micro-structural analysis of DN xerogels by 3D X-ray Microtomography indicated the presence of oriented pores in size range of 30–40 μm. To the best of our knowledge, Microtomography was used for the first time to study the DN gels. These hydrogels can be used to develop implants that can withstand prolonged stress and expand the life span of implants.

Preferential solute transport under variably saturated conditions in a silty loam soil: Is the shallow water table a driving factor?

A shallow water table might enhance preferential solute movement by modifying both the water flow and solute dynamics. In this study, we estimated soil hydraulic and solute transport parameters through a tracer experiment in lysimeters comparing different water table levels. In a set-up of 12 lysimeters, the bottom boundary condition was set as a water table depth of 120 cm, or 60 cm, or as free drainage. A tracer solution of bromide (250 mg l−1, 40 mm) was added to each lysimeter and soil water was sampled with suction cups at different depths for the following 174 days. Soil water content and matric potential were monitored using TDR probes and electronic tensiometers at the same depths. Soil hydraulic and solute transport parameters in different soil layers were estimated by inverse modeling using HYDRUS 1D. Soil hydraulic parameters were estimated from the Mualem-van Genuchten equations, while both the advection–dispersion (ADE) and physical non-equilibrium mobile-immobile water (MIM) models were used to describe the solute transport. Moreover, the soil pore network was analyzed by means of 3D X-ray microtomography. Results showed different solute dynamics between contrasting water table managements. With free drainage, solute in the immobile domain was negligible, and its transport was fully associated with the mobile water flow. In contrast, a shallow water table affected the tracer transport, by modifying a) the soil pore network, with an increase of the macropores and a reduction of the pore connectivity; b) the flow field, with an increase of immobile water and a reduction of αMIM, indicating slow exchange between mobile and immobile regions, in turn promoting preferential pathways. Hence, groundwater pollution might be worsened by preferential solute transport of agrochemicals occurring with shallow water table conditions.

On the production of novel zirconia-reinforced bioactive glass porous structures for bone repair

The objective of this study was to develop a replica method for producing zirconia-reinforced bioactive glass (ZRBG) porous structures for bone repair. Four different types of porous structures were produced: zirconia (G1), 58S BG-coated zirconia (G2), zirconia-reinforced BG (G3) and 58S BG-coated zirconia-reinforced BG (G4). A complete characterization of the specimens was performed via SEM-EDS, Archimedes method, 3D X-ray micro-tomography, micro-indentation, compressive strength tests and SBF immersion tests. G3 and G4 specimens presented a BG matrix (~ 33% glassy phase) with dispersed zirconia particles. The porosity of the specimens ranged from 86% up to 93%. BG58S-zirconia groups G3 and G4) exhibited lower YM (38.76 ± 11.20 GPa and 43.49 ± 2.16 GPa) than that of G1 monolithic zirconia specimens (94.39 ± 12.62 GPa), which were more compatible to that of the bone. No significant difference in compressive strength between BG58S-zirconia (G3: 0.41 ± 0.20 MPa; G4: 0.45 ± 0.11 MPa) and zirconia (G1: 0.32 ± 0.11 MPa) was detected observed (p > 0.05). In vitro SBF tests showed a potential bioactivity for ZRBG porous structures.

The influence of secondary processes on the porosity of volcanic rocks: A multiscale analysis using 3D X-ray microtomography

The porosity of volcanic rocks can be strongly affected by secondary processes such as the percolation of water and hydrothermal fluids, thus promoting crystallization of secondary minerals in the pores. With an aim to evaluate the impact of secondary mineral fillings, this paper shows the segmentation of secondary and filled pores based on the micro-CT technique. The mineralogy of the sample was analyzed with optical microscopy. Multiscale analysis was performed to determine the total porosity before and after the processes. The results show the influence on the permeability parameter caused by crystallization.