Synchrotron X-ray Microtomography Research Articles

Synchrotron X-ray Microtomography with Improved Image Quality by Ring Artifacts Correction for Structural Analysis of Insects.

Ring artifacts are undesirable and complicate the analysis and interpretation of microstructures in synchrotron X-ray microtomography. Here, we propose a new method to improve the image quality of an object by removing the ring artifacts and investigate the efficiency of this process with tomographic images of a dried Tenebrio molitor. In this method, before the tomographic reconstruction, ring artifacts were identified and located in the sinograms as line artifacts. Then, the identified line artifacts were corrected as single point noise via image processing of the original projections. Eventually, the corresponding line artifacts were removed, resulting in reduced ring artifacts in the reconstructed tomographic images. Simulations verified the efficiency of the proposed method. This method was successfully applied for the structural analysis of the insect T. molitor, showing superior performance in reducing ring artifacts in the tomographic image without noticeable loss of structural information.

A 4D view on the evolution of metamorphic dehydration reactions

Metamorphic reactions influence the evolution of the Earth’s crust in a range of tectonic settings. For example hydrous mineral dehydration in a subducting slab can produce fluid overpressures which may trigger seismicity. During reaction the mechanisms of chemical transport, including water expulsion, will dictate the rate of transformation and hence the evolution of physical properties such as fluid pressure. Despite the importance of such processes, direct observation of mineral changes due to chemical transport during metamorphism has been previously impossible both in nature and in experiment. Using time-resolved (4D) synchrotron X-ray microtomography we have imaged a complete metamorphic reaction and show how chemical transport evolves during reaction. We analyse the dehydration of gypsum to form bassanite and H2O which, like most dehydration reactions, produces a solid volume reduction leading to the formation of pore space. This porosity surrounds new bassanite grains producing fluid-filled moats, across which transport of dissolved ions to the growing grains occurs via diffusion. As moats grow in width, diffusion and hence reaction rate slow down. Our results demonstrate how, with new insights into the chemical transport mechanisms, we can move towards a more fundamental understanding of the hydraulic and chemical evolution of natural dehydrating systems.

Synchrotron Microtomography Reveals the Fine Three-Dimensional Porosity of Composite Polysaccharide Aerogels.

This study investigates the impact of ice-templating conditions on the morphological features of composite polysaccharide aerogels in relation to their mechanical behavior and aims to get a better insight into the parameters governing these properties. We have prepared polysaccharide aerogels of guar galactomannan (GM) and tamarind seed xyloglucan (XG) by enzymatic oxidation with galactose oxidase (GaO) to form hydrogels, followed by conventional and unidirectional ice-templating (freezing) methods and lyophilization to form aerogels. Composite polysaccharide aerogels were prepared by incorporating nanofibrillated cellulose (NFC) into polysaccharide solutions prior to enzymatic oxidation and gel formation; such a cross linking technique enabled the homogeneous distribution of the NFC reinforcement into the gel matrix. We conducted phase-enhanced synchrotron X-ray microtomography (XMT) scans and visualized the internal microstructure of the aerogels in three-dimensional (3D) space. Volume-weighted pore-size and pore-wall thickness distributions were quantitatively measured and correlated to the aerogels’ mechanical properties regarding ice-templating conditions. Pore-size distribution and orientation depended on the ice-templating methods and the NFC reinforcement that significantly determined the mechanical and shape-recovery behavior of the aerogels. The results obtained will guide the design of the microporous structure of polysaccharide aerogels with optimal morphology and mechanical behavior for life-sciences applications.

Alteration and Erosion of Rock Matrix Bordering a Carbonate-Rich Shale Fracture.

A novel reactive transport model has been developed to examine the processes that affect fracture evolution in a carbonate-rich shale. An in situ synchrotron X-ray microtomography experiment, flowing CO2 saturated water through a single fracture mini-core of Niobrara Shale provided the experimental observations for the development and testing of the model. The phenomena observed included the development of a porous altered layer, flow channeling, and increasingly limited calcite dissolution. The experimental observations cannot be explained by models that consider only mineral dissolution and development of an altered layer. The difference between the fracture volume change recorded by the microtomography images and what would be expected from mineral dissolution alone suggest that there is erosion of the altered layer as it develops. The numerical model includes this additional mechanism, with the erosion rate based on the thickness of the altered layer, and successfully captures the evolution of the geochemical reactions and morphology of the fracture. The findings imply that the abundance (with a threshold of approximately 35%) and reactivity of the rapidly reacting mineral control the development and erodibility of the altered layer on the fracture surfaces, and therefore fracture opening.

An investigation of the influence of moisture on fatigue damage mechanisms in a woven glass-fibre-reinforced PA66 composite using acoustic emission and infrared thermography

Abstract A woven glass-fibre-reinforced composite with a polyamide 6,6 matrix is considered for the purpose of being integrated into an automotive part. Fatigue tests were conducted on both [(0/90) 3 ] and [(±45) 3 ] stacking sequences. In order to analyze the influence of moisture content on the fatigue behaviour, samples were conditioned at RH0, RH50 and RH100. Although moisture content affects the fatigue life for high stress levels, this effect tends to disappear for low stress levels. This phenomenon was confirmed by additional fatigue tests in a climatic chamber. This paper aims to investigate damage mechanisms developing within the material during fatigue test in order to understand the origin of this phenomenon. Two in-situ non-destructive techniques were used in order to detail the fatigue damage scenario: namely, acoustic emission and infrared thermography. These techniques allow locating and differentiating the main damage mechanisms: matrix cracking, fibre/matrix debonding and fibre breakages. In addition, microscopic observations and synchrotron X-ray microtomography were realized on fatigue coupons to visualize fibre breakages. Results have highlighted an increase in the amount of fibre breakage when the applied fatigue stress decreases, which explains the observed phenomenon.

Dynamics of snap-off and pore-filling events during two-phase fluid flow in permeable media

Understanding the pore-scale dynamics of two-phase fluid flow in permeable media is important in many processes such as water infiltration in soils, oil recovery, and geo-sequestration of CO2. The two most important processes that compete during the displacement of a non-wetting fluid by a wetting fluid are pore-filling or piston-like displacement and snap-off; this latter process can lead to trapping of the non-wetting phase. We present a three-dimensional dynamic visualization study using fast synchrotron X-ray micro-tomography to provide new insights into these processes by conducting a time-resolved pore-by-pore analysis of the local curvature and capillary pressure. We show that the time-scales of interface movement and brine layer swelling leading to snap-off are several minutes, orders of magnitude slower than observed for Haines jumps in drainage. The local capillary pressure increases rapidly after snap-off as the trapped phase finds a position that is a new local energy minimum. However, the pressure change is less dramatic than that observed during drainage. We also show that the brine-oil interface jumps from pore-to-pore during imbibition at an approximately constant local capillary pressure, with an event size of the order of an average pore size, again much smaller than the large bursts seen during drainage.

Quantitative characterization of soil micro-aggregates: New opportunities from sub-micron resolution synchrotron X-ray microtomography

Soil microaggregates are the fundamental building block, at the micron scale, of the highly hierarchical structure of soils, and can exert a significant control on the local biological metabolism and microbial community partitioning. In this study we propose an analysis protocol for the morphometric characterization of complete soil microaggregates based on sub-micron resolution synchrotron X-ray microtomography. A comprehensive characterization of the aggregate morphology is the first step towards a complete characterization of the soil microaggregates, when trying to correlate morphometric parameters with physical and/or biological properties, or when building models (e.g., effective diffusivity, microbial distribution, etc.). We demonstrate our characterization approach on two single microaggregate samples from dramatically different soil environments: one from Kansas, primarily composed by inorganic particles, and one from Barrow (Alaska) dominated by plant fragments. A series of state-of-the-art morphometric analysis techniques have been employed providing quantitative results highlighting specific differences of the two samples. The role of the microstructure in a scenario microbial population development has been discussed and it has been found that the Barrow microaggregate seems to be more favorable, from a purely geometrical point of view, as also confirmed by a simple model presented in this work. The potential of this approach, when coupled with chemical and biological analysis for a fully comprehensive characterization of soil aggregates in the larger picture of enhanced biological activity, is evident.

Synchrotron X-ray micro-tomography at the Advanced Light Source: Developments in high-temperature in-situ mechanical testing

At the Advanced Light Source (ALS), Beamline 8.3.2 performs hard X-ray micro-tomography under conditions of high temperature, pressure, mechanical loading, and other realistic conditions using environmental test cells. With scan times of 10s–100s of seconds, the microstructural evolution of materials can be directly observed over multiple time steps spanning prescribed changes in the sample environment. This capability enables in-situ quasi-static mechanical testing of materials. We present an overview of our in-situ mechanical testing capabilities and recent hardware developments that enable flexural testing at high temperature and in combination with acoustic emission analysis.

Airflow and particle transport simulations for predicting permeability and aerosol filtration efficiency in fibrous media

In this work, synchrotron X-ray microtomography was used to produce high spatial resolution images of two kinds of binderless and monodisperse fibrous filter media, made of fiberglass and sintered stainless steel respectively. Representative computational domains were created based on these images. Both flow and collection efficiency simulations were then carried out using the flow and particle transport modules of the GeoDict® code. An image analysis program based on Matlab® was used to determine the structural properties of the computational domain, namely the thickness, the solid volume fraction and the fiber size distribution. In parallel, permeability and collection efficiency measurements were performed on the same media, to provide an experimental comparison. Very good agreement was found between the experimental and the simulated permeability values. We showed that, in order to compare collection efficiency from experiments with those simulated with GeoDict®, it was necessary to take into account the difference between the thickness of the fibrous structures that were used to create the calculation domain, and the averaged experimental thickness characterized by SEM. Using this way of comparison, we obtained the first experimental validation of the GeoDict® code on both permeability and efficiency aspects for aerosols filtration.

The fossil species Merothrips dietrichi (Schliephake) comb.n. redescribed and transferred from the genus Heterothrips (Thysanoptera).

Identifying and describing fossil thrips (Thysanoptera) sometimes touches the limits of feasibility. Complications handling these tiny fossils are not only caused by their size, their position or fragmentary nature, but also by the state and condition of the matrices surrounding them. Due to poor preservation in some matrices (such as lime, potash and lignite) their identification often remains uncertain (Ulitzka 2015a). Amber, however, considered as a window on times past (Gröhn et al. 2015), presents a wide range of insect inclusions in excellent condition. Nevertheless, many problems can impede our visibility through this 'window'. Fissures, opacity or clouding in the fossil resin, as well as inclusions or bubbles of air, can cover specific characteristics of an included specimen. Curvature of the amber surface results in optical distortions that can impede a reliable assessment of certain features, and the deeper an inclusion is in the amber the greater are the problems. For these reasons cutting or grinding the amber as close as possible to a specimen is essential. In the future, synchrotron X-ray microtomography may be an alternative (Henderickx et al. 2012; van de Kamp et al. 2014), but at present is too complex and expensive.

Initiation and growth kinetics of solidification cracking during welding of steel

Solidification cracking is a key phenomenon associated with defect formation during welding. To elucidate the failure mechanisms, solidification cracking during arc welding of steel are investigated in situ with high-speed, high-energy synchrotron X-ray radiography. Damage initiates at relatively low true strain of about 3.1% in the form of micro-cavities at the weld subsurface where peak volumetric strain and triaxiality are localised. The initial micro-cavities, with sizes from 10 × 10−6 m to 27 × 10−6m, are mostly formed in isolation as revealed by synchrotron X-ray micro-tomography. The growth of micro-cavities is driven by increasing strain induced to the solidifying steel. Cavities grow through coalescence of micro-cavities to form micro-cracks first and then through the propagation of micro-cracks. Cracks propagate from the core of the weld towards the free surface along the solidifying grain boundaries at a speed of 2–3 × 10−3 m s−1.

Micro-tomography based analysis of thermal conductivity, diffusivity and oxidation behavior of rigid and flexible fibrous insulators

Material properties and oxidation behavior of low-density felts used as substrates for conformal carbon/phenolic ablators were compared with those of a rigid carbon fiber preform used to manufacture heritage lightweight ablators. Synchrotron X-ray micro-tomography measurements were performed to characterize the materials’ microstructure at the scale of the fibers. Using the tomography voxels as computational grids, tortuosity in the continuum regime, and room temperature conductivity were computed. Micro-scale simulations of the oxidation of carbon fibers were carried out using a random walk model for oxygen diffusion and a sticking probability law to model surface reactions. The study shows that, due to a higher porosity and lower connectivity, the felt materials have lower thermal conductivity but a faster recession rate than that of the rigid preform. Challenges associated with computations based on micro-tomography are also discussed.

Development of synchrotron X-ray micro-tomography under extreme conditions of pressure andtemperature.

X-ray tomography is a non-destructive three-dimensional imaging/microanalysis technique selective to a wide range of properties such as density, chemical composition, chemical states and crystallographic structure with extremely high sensitivity and spatial resolution. Here the development of in situ high-pressure high-temperature micro-tomography using a rotating module for the Paris-Edinburgh cell combined with synchrotron radiation is described. By rotating the sample chamber by 360°, the limited angular aperture of ordinary high-pressure cells is surmounted. Such a non-destructive high-resolution probe provides three-dimensional insight on the morphological and structural evolution of crystalline as well as amorphous phases during high pressure and temperature treatment. To demonstrate the potentials of this new experimental technique the compression behavior of a basalt glass is investigated by X-ray absorption tomography, and diffraction/scattering tomography imaging of the structural changes during the polymerization of C60 molecules under pressure is performed. Small size and weight of the loading frame and rotating module means that this apparatus is portable, and can be readily installed on most synchrotron facilities to take advantage of the diversity of three-dimensional imaging techniques available at beamlines. This experimental breakthrough should open new ways for in situ imaging of materials under extreme pressure-temperature-stress conditions, impacting diverse areas in physics, chemistry, geology or materials sciences.

Highly CO2-supersaturated melts in the Pannonian lithospheric mantle – A transient carbon reservoir?

Subduction of carbonated crust is widely believed to generate a flux of carbon into the base of the continental lithospheric mantle, which in turn is the likely source of widespread volcanic and non-volcanic CO2 degassing in active tectonic intracontinental settings such as rifts, continental margin arcs and back-arc domains. However, the magnitude of the carbon flux through the lithosphere and the budget of stored carbon held within the lithospheric reservoir are both poorly known. We provide new constraints on the CO2 budget of the lithospheric mantle below the Pannonian Basin (Central Europe) through the study of a suite of xenoliths from the Bakony-Balaton Highland Volcanic Field. Trails of secondary fluid inclusions, silicate melt inclusions, networks of melt veins, and melt pockets with large and abundant vesicles provide numerous lines of evidence that mantle metasomatism affected the lithosphere beneath this region. We obtain a quantitative estimate of the CO2 budget of the mantle below the Pannonian Basin using a combination of innovative analytical and modeling approaches: (1) synchrotron X-ray microtomography, (2) NanoSIMS, Raman spectroscopy and microthermometry, and (3) thermodynamic models (Rhyolite-MELTS). The three-dimensional volumes reconstructed from synchrotron X-ray microtomography allow us to quantify the proportions of all petrographic phases in the samples and to visualize their textural relationships. The concentration of CO2 in glass veins and pockets ranges from 0.27 to 0.96wt.%, higher than in typical arc magmas (0–0.25wt.% CO2), whereas the H2O concentration ranges from 0.54 to 4.25wt.%, on the low end for estimated primitive arc magmas (1.9–6.3wt.% H2O). Trapping pressures for vesicles were determined by comparing CO2 concentrations in glass to CO2 saturation as a function of pressure in silicate melts, suggesting pressures between 0.69 to 1.78GPa. These values are generally higher than trapping pressures for fluid inclusions determined by Raman spectroscopy and microthermometry (0.1–1.1GPa). The CO2/silicate melt mass ratios in the metasomatic agent that percolated through the lithospheric mantle below the Pannonian Basin are estimated to be between 9.0 and 25.4wt.%, values consistent with metasomatism either by (1) silicate melts already supersaturated in CO2 before reaching lithospheric depths or (2) carbonatite melts that interacted with mantle peridotite to generate carbonated silicic melts. Taking the geodynamical context of the Pannonian Basin and our calculations of the CO2/silicate melt mass ratios in the metasomatic agent into account, we suggest that slab-derived melts initially containing up to 25wt.% of CO2 migrated into the lithospheric mantle and exsolved CO2–rich fluid that became trapped in secondary fluid inclusions upon fracturing of the peridotite mineral matrix. We propose a first-order estimate of 2000ppm as the minimal bulk CO2 concentration in the lithospheric mantle below the Pannonian Basin. This transient carbon reservoir is believed to be degassed through the Pannonian Basin due to volcanism and tectonic events, mostly focused along the lithospheric-scale regional Mid-Hungarian shear Zone.

Studying model suspensions using high resolution synchrotron X-ray microtomography

The addition of minor quantities of secondary liquids to suspensions may lead to a transition from a fluid-like structure to paste-like structure for the system. Previous studies have shown how rheological properties such as viscosity and yield stress are affected, however, qualitative visual observation on the micro-scale during both short and long term storage has yet to be achieved or reported.This research focuses on the movement of a secondary immiscible liquid (water or saturated sucrose solution) when added to a model food system. The model food system used in this study is a suspension of sucrose particles in a continuous oil phase to better understand the interactions between the particles and the liquid phases present. This was accomplished using dynamic X-ray computer tomography to study the behaviour of the sample. This non-destructive approach allowed the movement of the secondary liquid as well as the solid particles from the bulk suspension to be monitored through a time lapse of scans. This was achieved by observing the changes in the grey scale range of the droplet with time, which was then correlated to the uptake and movement of sucrose into the secondary liquid using an innovative method. This movement was due to the hydrophilicity and solubility of sucrose with gravity/sedimentation playing a minimal role.

100-million-year-old conifer tissues from the mid-Cretaceous amber of Charente (western France) revealed by synchrotron microtomography.

Terrestrial plant remains in fossilized tree resin are relatively common. However, histology and preservation of plants entombed in Cretaceous ambers remain poorly known. We report an exquisitely preserved conifer leafy axis from 100-million-year-old opaque amber of western France that is assignable to Glenrosa carentonensis Moreau, Néraudeau, Tafforeau & Dépré. The purpose of this paper is to discuss the taphonomy and the use of microtomography for studies of palaeobotanical remains in amber. A leafy axis was examined using propagation phase-contrast X-ray synchrotron microtomography with voxel sizes of 14·9, 1·4, and 0·7 μm. The conifer leafy axis described is preserved in three dimensions. Despite desiccation of the specimen within the surrounding amber, the cuticle, as well as most of inner tissues, is preserved in three dimensions down to the cellular level. Epidermis, palisade parenchyma, spongy parenchyma, transfusion tracheids and vascular bundles are clearly distinguished. Gross morphology and histology of the specimen were revealed using synchrotron microtomography, allowing an unprecedented resolution for the study of soft-bodied plants entombed in amber. The study reveals a peculiar combination of authigenic and duripartic preservation as well as permineralization, and highlights the complexity of taphonomic processes that can occur in amber inclusions. This fossil demonstrates the difficulty of studying amber-preserved plant remains under certain conditions.

Three-dimensional paleohistology of the scale and median fin spine of Lophosteus superbus (Pander 1856).

Lophosteus superbus is one of only a handful of probable stem-group osteichthyans known from the fossil record. First collected and described in the late 19th century from the upper Silurian Saaremaa Cliff locality in Estonia, it is known from a wealth of disarticulated scales, fin spines, and bone fragments. In this study we provide the first description of the morphology and paleohistology of a fin spine and scale from Lophosteus using virtual thin sections and 3D reconstructions that were segmented using phase-contrast synchrotron X-ray microtomography. These data reveal that both structures have fully or partially buried odontodes, which retain fine morphological details in older generations, including sharp nodes and serrated ridgelets. The vascular architecture of the fin spine tip, which is composed of several layers of longitudinally directed bone vascular canals, is much more complex compared to the bulbous horizontal canals within the scale, but they both have distinctive networks of ascending canals within each individual odontode. Other histological characteristics that can be observed from the data are cell spaces and Sharpey’s fibers that, when combined with the vascularization, could help to provide insights into the growth of the structure. The 3D data of the scales from Lophosteus superbus is similar to comparable data from other fossil osteichthyans, and the morphology of the reconstructed buried odontodes from this species is identical to scale material of Lophosteus ohesaarensis, casting doubt on the validity of that species. The 3D data presented in this paper is the first for fossil fin spines and so comparable data is not yet available. However, the overall morphology and histology seems to be similar to the structure of placoderm dermal plates. The 3D datasets presented here provide show that microtomography is a powerful tool for investigating the three-dimensional microstructure of fossils, which is difficult to study using traditional histological methods. These results also increase the utility of fin spines and scales suggest that these data are a potentially rich source of morphological data that could be used for studying questions relating to early vertebrate growth and evolution.

Palaeobiology of tanaidaceans (Crustacea: Peracarida) from Cretaceous ambers: extending the scarce fossil record of a diverse peracarid group

Diverse assemblages of tanaidacean peracarid crustaceans from western Tethyan continental deposits suggest that the group was relatively common in or around ancient resin-producing forests. Here we report the results of an examination of 13 tanaidacean specimens from three Cretaceous (Albian to Turonian) French amber deposits. Two new species of the fossil family Alavatanaidae are placed in the previously described Early Cretaceous genus Eurotanais: Eurotanais pyrenaensis sp. nov. from Cenomanian Pyrenean amber (Fourtou, Aude) and Eurotanais seilacheri sp. nov. from Turonian Vendean amber (La Garnache, Vendee). The remaining specimens are placed in three newly erected genera and species (but family incertae sedis): Arcantitanais turpis gen. et sp. nov. from Albian–Cenomanian Charentese amber (Archingeay, Charente-Maritime), and Tytthotanais tenvis gen. et sp. nov. and Armadillopsis rara gen. et sp. nov. from Pyrenean amber. These are the first formally described fossils that might be related to the paratanaoidean families Nototanaidae and Paratanaidae, sharing with these some putatively derived features and providing possible evidence for the antiquity and morphological stability of these families and the suborder Tanaidomorpha. The distinctive features and character combinations of these fossil taxa are discussed in connection with possible relationships to the living lineages of tanaidaceans. Propagation phase-contrast X-ray synchrotron microtomography was used to obtain high-quality 3D images for some fossils. A discussion is provided on the putative palaeobiology of tanaidaceans and the French resiniferous forest ecosystem. The discovery of these new tanaidaceans extends the palaeogeographical distribution and stratigraphical range of the family Alavatanaidae and sheds new light on the palaeoecology and diversity of tanaidaceans in pre-angiospermous woodlands.

Pore-scale multiphase flow modeling and imaging of CO2 exsolution in Sandstone

This study utilizes synchrotron X-ray micro-tomography and pore scale modeling to investigate the process of gas exsolution and how it affects non-wetting phase relative permeability. Exsolved gas distributions are measured on Domengine and Boise sandstone samples using synchrotron X-ray micro-tomography. Observed gas phase distributions are compared to a new model that simulates the growth and distribution of exsolved gas phase at the pore-scale. Water relative permeability curves are calculated using a Stokes flow simulator with modeled and observed gas distributions, under various conditions, such as rock geometry, and pressure depletion rates. By comparing the actual bubble distributions with modeled distributions, we conclude that exsolved gas is more likely to form and accumulate at locations with higher water velocities. This suggests that convective delivery of CO2 to the gas bubble is a primary mechanism for bubble growth, as compared to diffusive transport through the aqueous phase. For carbonated brine flowing up a fault at half a meter per day, with 5% exsolved gas, the water relative permeability is estimated to be 0.6∼0.8 for various sandstones. The reduction of water mobility reduces upward brine migration when even a small amount of exsolution occurs.

A novel protocol for resolving feldspar crystals in synchrotron X-ray microtomographic images of crystallized natural magmas and synthetic analogs

X-ray computed microtomography is a non-destructive imaging technique recognized in the geosciences as a powerful tool to investigate rock textures directly in three dimensions (3D) at the micrometer and sub-micrometer scale. The quantitative morphological and textural analysis of images requires segmentation and characterization of phases in the reconstructed volume based upon their gray levels (related to their relative X-ray attenuation) and/or morphological aspects. Often the differences in X-ray attenuation of some phases are so small that no contrast is observed in the reconstructed slices or, although the human eye can discern the differences between these phases, it is difficult, or sometimes impossible, to reliably segment and separately analyze these phases. Facing this challenge, we propose an experimental and computational procedure that allows the segmentation of phases with small density variations in geomaterials. By using an experimental protocol based on phase-contrast synchrotron X-ray microtomography combined with a customized 3D image processing procedure, we successfully segmented feldspar from the glassy matrix in both a natural volcanic sample and a synthetic analog. Our results demonstrate that crystallized natural volcanic rocks and synthetic analogs can be characterized by synchrotron X-ray phase-contrast microtomography and that phase-retrieval processing is an invaluable tool for the reconstruction of 3D multiphase textures.