Marco VoltoliniUniversity of Milan | UNIMI
Marco Voltolini
PhD
About
81
Publications
21,605
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
2,109
Citations
Introduction
Additional affiliations
June 2012 - present
January 2011 - June 2012
January 2011 - June 2012
Publications
Publications (81)
The gut is continuously invaded by diverse bacteria from the diet and the environment, yet microbiome composition is relatively stable over time for host species ranging from mammals to insects, suggesting host-specific factors may selectively maintain key species of bacteria. To investigate host specificity, we used gnotobiotic Drosophila, microbi...
The behavior of heated bentonite buffer is critical for the security and long-term performance of a geological
repository for high-level radioactive waste (HLW). While laboratory column experiments have been conducted to
investigate compacted bentonite and coupled THMC (thermal-hydro-mechanical and chemical) processes for a
moderate temperature ran...
Estimating porous media properties is a vital component of geosciences and the physics of porous media. Until now, imaging techniques have focused on methodologies to match image-derived flows or geomechanical parameters with experimentally identified values. Less emphasis has been placed on the compromise between image processing techniques and th...
The investigation of jellyfish gastrovascular systems mainly focused on stain injections and dissections, negatively affected by thickness and opacity of the mesoglea. Therefore, descriptions are incomplete and data about tridimensional structures are scarce. In this work, morphological and functional anatomy of the gastrovascular system of Rhizost...
In this work, we propose the software library PyPore3D, an open source solution for data processing of large 3D/4D tomographic data sets. PyPore3D is based on the Pore3D core library, developed thanks to the collaboration between Elettra Sincrotrone (Trieste) and the University of Trieste (Italy). The Pore3D core library is built with a distinction...
We present micromechanical modeling of an indentation experiment on Green River Shale with simultaneous X-ray micro-computed tomography of internal sample deformation that provides new insights into the ductile-brittle micromechanical behavior of shales relevant to proppant embedment. Brittle wing cracks appear from the indenter along the shale bed...
Beamline 11.3.1 at the Advanced Light Source is a tender/hard (6-17 keV) x-ray bend magnet beamline recently re-purposed with a new full-field, nanoscale transmission x-ray microscope. The microscope is designed to image composite and porous materials possessing a submicrometer structure and compositional heterogeneity that determine materials' per...
The intestines of animals are typically colonized by a complex, relatively stable microbiota that influences health and fitness, but the underlying mechanisms of colonization remain poorly understood. As a typical animal, the fruit fly, Drosophila melanogaster, is associated with a consistent set of commensal bacterial species, yet the reason for t...
Oil and gas shales are a system where understanding the mechanical properties at the microscale is of paramount importance, e.g. to better understand the behavior of proppant-shale contacts and their role in the evolution of propped fractures in unconventional reservoirs. This work shows for the first time an experiment coupling indentation testing...
This paper describes a new modeling framework for microscopic to reservoir-scale simulations of hydraulic fracturing and production. The approach builds upon a fusion of two existing high-performance simulators for reservoir-scale behavior: the GEOS code for hydromechanical evolution during stimulation and the TOUGH+ code for multi-phase flow durin...
The Cedars ultramafic block hosts alkaline springs (pH > 11) in which calcium carbonate forms upon uptake of atmospheric CO2 and at times via mixing with surface water. These processes lead to distinct carbonate morphologies with “floes” forming at the atmosphere-water interface, “snow” of fine particles accumulating at the bottom of pools and terr...
The proppant embedment due to creep in shales is a known issue affecting the usable lifetime of wells in unconventional oil and gas recovery. One of the factors influencing creep is the presence of organics, whose properties can be very sensitive to temperature. In this work we investigated for the first time the role of temperature-induced creep i...
Enhanced Geothermal Systems (EGS) offer the potential for a much larger energy source than conventional hydrothermal systems. Hot, low-permeability rocks are prevalent at depth around the world, but the challenge of extracting thermal energy depends on the ability to create and sustain open fracture networks. Laboratory experiments were conducted u...
The detailed mechanisms of the sealing of a single fracture, from hydration to almost complete closure by increase of confining pressure, as monitored from in situ synchrotron X-ray microtomography during the flow of carbonated water, is here shown for the first time. Different mechanisms play the key role at different stages in the evolution of th...
The behavior of proppant at the microscale during fracture closure in oil and gas shales is not yet well understood. In this context, we used a combination of dynamic synchrotron X-ray micro computed tomography with morphometric analysis and flow modeling to provide new insight into the dominant physical processes acting at the microscale during fr...
Flow through fractures dominates the movement of fluids in a variety of natural as well as engineered subsurface systems. Microbial activities in fractured rock impact subsurface energy recovery, storage and waste disposal. It has been recognized that understanding how the contrasting permeability between fracture and matrix interacts with microbia...
The injection of CO2-rich fluids in carbonate rocks results in an evolution of the pore space, with consequent changes in the hydraulic properties of the reservoir; how these properties evolve, particularly for parameters relevant to multiphase flow e.g. Pc(s), remains a topic of active research despite several decades of study. We have carried out...
A new experimental triaxial cell for in situ synchrotron X-ray micro-computed tomography aimed at imaging small samples of (6 mm × 19 mm) at high temperatures (up to 400°C) and pressures (up to 24 MPa confining) is presented. The system has flow-through capabilities, independent axial and radial pressure control, and has been developed and tested a...
Predicting the temporal evolution of fractures in impermeable sealing units above geological carbon storage reservoirs is crucial to understanding leakage risk as well as optimal selection of storage sites. Process models are required which couple geochemical, hydrological, and mechanical effects to predict whether transmissive fractures increase o...
Clinopyroxene and plagioclase (andesine) microlites in an obsidian flow from Glass Mountain (NE California, USA) display strong alignment. Synchrotron X-ray diffraction, coupled with Rietveld analysis, was used to quantify crystallographic-preferred orientation (CPO). Clinopyroxene, with a rod-shaped morphology, shows a strong alignment of [001] in...
Significance
Reliable estimates of geologic carbon storage capacities (needed for policymaking) in both saline aquifers and unconventional gas/oil shales rely on understanding trapping mechanisms. We found that CO 2 uptake by muscovite (a common mineral and a conservative proxy for illite) far exceeds the maximum adsorption capacity of its external...
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...
Continuous improvements at X-ray imaging beamlines at synchrotron light sources have made dynamic synchrotron X-ray micro-computed tomography (SXR-µCT) experiments more routinely available to users, with a rapid increase in demand given its tremendous potential in very diverse areas. In this work a survey of five different four-dimensional SXR-µCT...
Pore-scale distribution of supercritical CO2 (scCO2) exerts significant control on a variety of key hydrologic as well as geochemical processes, including residual trapping and dissolution. Despite such importance, only a small number of experiments have directly characterized the three-dimensional distribution of scCO2 in geologic materials during...
The performance of geologic CO2 sequestration (GCS) can be affected by CO2 mineralization and changes in the permeability of geologic formations resulting from interactions between water-bearing supercritical CO2 (scCO2) and silicates in reservoir rocks. However, without understanding size effects, the findings in previous studies using nanometer o...
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 th...
A CO2-brine drainage and imbibition cycle was performed in a Boise sandstone sample at reservoir conditions (1300 PSI, 44°C) at the Advanced Light Source, LBNL. The sample was repeatedly imaged, at the pore-scale, using synchrotron-based X-ray microtomography. In particular the temporal evolution of residually trapped CO2 was monitored for about 30...
A multi-scale synchrotron-based X-ray microtomographic dataset of residually trapped air after gravity-driven brine imbibition was acquired for three samples with differing pore topologies and morphologies; image volumes were reconstructed with voxel sizes from 4.44 µm down to 0.64 µm. Capillary pressure distributions among the population of trappe...
The rates of mineral dissolution reactions in porous media are difficult to predict, in part because of a lack of understanding of mineral reactive surface area in natural porous media. Common estimates of mineral reactive surface area used in reactive transport models for porous media are typically ad hoc and often based on average grain size, inc...
Recent studies of carbonate surface reactivity have underscored the fundamental variability of dissolution rates and the heterogeneous distribution of the reaction over the mineral surface due to the inhomogeneous distribution of surface energy. Dolomite dissolution rates relative to different cleavage planes (r-planes) and surfaces cut approximate...
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 compar...
Understanding fracture alteration resulting from geochemical reactions is critical in predicting fluid migration in the subsurface, and is relevant to multiple environmental challenges. Here, we present a novel 2.5D continuum reactive transport model that captures and predicts the spatial pattern of fracture aperture change and the development of a...
Our limited understanding of mineral reactive surface area contributes to significant uncertainties in quantitative simulations of reactive chemical transport in subsurface processes. Continuum formulations for reactive transport typically use a number of different approximations for reactive surface area, including geometric, specific, and effecti...
Synchrotron radiation micro computed tomography (SR Micro CT) and micro X-ray diffraction (SR Micro XRD) were used to investigate the deleterious effects of alkali-silica reaction (ASR) in mortar bars. The samples were prepared by mixing ordinary Portland cement and chert, the latter consists of quartz crystals known to be potentially alkali-silica...
Volcanogenic sandstones are typically rich in volcanic rock fragments that can provide reactive minerals for CO2 mineralization in a scenario of CO2 sequestration. To quantitatively evaluate the extent and time scale of CO2 mineralization in potential reservoir formations, we characterized example high-porosity volcanic sand from the San Joaquin Va...
The properties of cementitious materials are related to the microstructure of their binder matrix, which develops, during cement hydration, by a sequence of dissolution–precipitation reactions. Here, microstructural development is monitored during hydration by synchrotron X-ray diffraction-enhanced computed microtomography (XRD-CT). This innovative...
The nucleation and growth processes of spherulitic alkali feldspar have been investigated in this study through X-ray microtomography and electron backscatter diffraction (EBSD) data. Here we present the first data on Shape Preferred Orientation (SPO) and Crystal Preferred Orientation (CPO) of alkali feldspar within spherulites. The analysis of syn...
The anisotropy of a rock is intimately related to the development of shape-preferred orientations (SPOs) and crystallographic-preferred orientations (CPOs). Quantifying the threedimensional (3D) CPOs and SPOs in natural rocks is therefore critical for understanding the processes underlying the development of anisotropy. In this work, we present a C...
The 3D phase distribution of cement pastes evolves during hydration and controls the rheology and mechanical properties of the paste. Synchrotron powder-diffraction micro-tomographic imaging is here employed to assess the cement phase spatial distribution in a totally non-invasive way. This technique can be used to produce distribution maps of the...
Two complementary 3D techniques, neutron diffraction and synchrotron X-ray microtomography (SXR-μCT), were used to compare the Shape and Lattice Preferred Orientations of a mylonitised metagranite from the Monte Rosa unit (Western Alps, Italy). The goal of using these techniques was to obtain two different orientation distribution functions. Althou...
This study shows the first textural data on synthetic alkali-feldspar
spherulites grown in trachytic melts during cooling and decompression
experiments with water-saturated conditions. Previous textural studies
have shown the shape evolution and the growth process of spherulites as
a function of undercooling (T) and water content, although just in...
The present work describes some new improvements concerning the analysis of cement hydration processes using ‘pencil-beam’ synchrotron X-ray diffraction tomography. (i) A new filtering procedure, applied to the diffraction images, has been developed to separate the powder-like contribution from that of the grains in the diffraction images. (ii) In...
This article describes a single-shot methodology to derive an average coating thickness in multi-particle coreshell systems exhibiting high X-ray absorption. Powder composed of UMo alloy particles surrounded by a micrometre-thick UO2 protective layer has been used as a test sample. Combining high-energy X-ray diffraction and laser granulometry, the...
An investigation of Calcium Silicate Hydrate (C–S–H) topological distribution and modes of precipitation is performed by combining X-ray powder diffraction tomography, performed on an ordinary Portland cement sample, with a numerical scheme
that simulates C–S–H precipitation. C–S–H distribution maps obtained both experimentally and numerically are...
Reliable assessment of the potential alkali reactivity of aggregate to develop deleterious alkali–silica reaction is essential for construction of durable concrete structures. The potential alkali reactivity of silicified limestone and two limestones has been investigated. Preliminary characterisation of aggregate was performed by optical and envir...
The behavior of the zeolite laumontite during dissolution in acidic aqueous solutions has been studied by fluid-cell atomic
force microscopy, with a focus on the role of the framework Al atoms in controlling the dissolution mechanisms. Isothermal
single etch pits dissolution rates have been measured in situ at three different temperatures (11, 23,...
X-ray Micro-CT is a technique of choice for the investigation of the internal features of materials. One typical necessary compromise is the choice of the resolution vs the size of the field of view. Cellular morphology analysis of foams can benefit from Micro-CT because both physical (low and high strain rate mechanical properties) and functional...
Absorption-based X-ray micro-tomography (X-μCT) provides fundamental in-situ information on the 3D microstructure of complex multiphase materials such as cements. However, since the phases present in a hydrating cement paste may be characterized by similar values of the attenuation coefficient, leading to low absorption contrast between different c...
Alkali–silica reaction (ASR) is one of the most important weathering processes in cement-based materials. The damages caused
by ASR have been qualitatively investigated with a number of different techniques. In this study, we present a procedure to
obtain quantitative morphological parameters of the ASR reaction effects using synchrotron X-ray micr...
Hydroxylpatite crystallites in lamellar bone show preferred orientation. In this study, the texture (lattice preferred orientation) of the crystallites in cortical bone samples has been studied by means of synchrotron hard X‐ray diffraction, performing a combined analysis with the Rietveld method to quantify fully the preferred orientation features...
The textures of an Al thin film and of -MnS nanocrystals deposited on a carbon film grid have been analysed using powder electron diffraction. For each sample a series of powder electron diffraction patterns tilted with respect to two orthogonal axes were collected, to adapt to this type of data the texture analysis procedures commonly used in sync...
Synchrotron radiation microtomography was used as a nondestructive imaging technique to investigate the microstructural properties of green and roasted coffee beans. After image acquisition, 2D images have been reconstructed and 3D images of the beans have been then obtained. Qualitative and quantitative analysis of the images allow to fully charac...
Samples of fault gouge from the San Andreas Fault drill hole (SAFOD), a shale from the North Sea sedimentary basin and schists from metamorphic rocks in the Alps have been analyzed with high energy synchrotron X-rays to determine preferred orientation of mica and clay minerals. The method relies on obtaining 2D diffraction images which are then pro...
We report a structural phase transition in AuIn2 above 25 GPa. The inferred structure of this phase is post cotunnite (P1121/a). Combining the new results with previously observed behavior of AuIn2, we propose a sequence of structural transitions from CaF2 (Fm3m) to amorphous phase at 24 GPa to monoclinic (P1121/a) structure at 25.6 GPa. During dec...
Preferred orientation in rocks is strongly related to the their physical properties; as an example, rock mechanical properties are strongly influenced by crystal alignment, and anisotropy in rock permeability can be influenced by pore shape and alignment. To obtain quantitative information about the preferred orientation of crystals the most widesp...
Many research fields in Geosciences require the knowledge of the three-dimensional (3D) texture of rocks. X-ray computed microtomography (muCT) supplies an effective method to directly acquire 3D information. Transmission X-ray muCT is a non-destructive technique based on the mapping of the linear attenuation coefficient of X-rays crossing the inve...
Turbostratic disorder, consisting in a disorder in which different layers have different rotations with respect to an axis, is commonly found in montmorillonite. The effect of this kind of disorder on diffraction profiles is significant and must be taken into account, especially in quantitative phase analysis. The effect of the turbostratic disorde...
Recent high-pressure studies have shown that an electronic spin transition of iron in ferropericlase, an expected major phase
of Earth’s lower mantle, results in changes in its properties, including density, incompressibility, radiative thermal conductivity,
electrical conductivity, and sound velocities. To understand the rheology of ferropericlase...
Samples of quartz-bearing rocks were heated above the α (trigonal)–β (hexagonal) phase transformation of quartz (625–950°C)
to explore changes in preferred orientation patterns. Textures were measured both in situ and ex situ with neutron, synchrotron
X-ray and electron backscatter diffraction. The trigonal–hexagonal phase transformation does not c...
A first attempt to investigate samples affected by alkali-silica reaction (ASR) by synchrotron X-ray microtomography has been
made. The setup available at the SYRMEP beamline, at the third generation synchrotron Elettra (Trieste, Italy), allowed collecting
phase-contrast enhanced images, with a detectability approaching that of optical microscopy (...
The anisotropy of physical properties is a well-known charac-teristic of many clay-bearing rocks. This anisotropy has impor-tant implications for elastic properties of rocks and must be con-sidered in seismic prospecting. Preferred orientation of clay min-erals is an important factor causing anisotropy in clay-bearing rocks such as shales and mudst...
Anisotropy in clay-rich sedimentary rocks is receiving increasing attention. Seismic anisotropy is essential in the prospecting for petroleum deposits. Anisotropy of diffusion has become relevant for environmental contaminants, including nuclear waste. In both cases, the orientation of component minerals is a critical ingredient and, largely becaus...
With a membrane based mechanism to allow for pressure change in a sample in a radial diffraction diamond anvil cell and simultaneous infrared laser heating, it is now possible to investigate texture changes during deformation and phase transformations over a wide range of temperature-pressure conditions. The device is used to study bcc (α) , fcc (γ...
Samples of fault gouge from the San Andreas Fault drill hole (SAFOD), shales from several sedimentary basins and schists from greenschist facies metamorphic rocks in the Alps have been analyzed with high energy synchrotron X-rays to determine preferred orientation of mica and clay minerals. The method relies on obtaining 2D diffraction images which...
Magnesium silicate perovskite is thought to be the major constituent of the lower mantle. Consequently, knowledge of the deformation behavior of MgSiO3 perovskite is important for understanding the geodynamic behavior in the deep Earth as well as interpreting observed seismic anisotropy. One mechanism that can generate anisotropy is dislocation gli...
Long-term leaching tests on concretes have been performed to investigate portlandite dissolution by means of X-ray powder diffraction and the Rietveld method, which reveals a promising approach to detect CH content in leached concrete. Several concrete samples have been prepared and immersed in deionised water for 0, 35, 99 and 150 days. The result...
Anisotropy of shales is the subject of this report, and we use an example of the Jurassic Opalinus Clay from Mont Terri (Switzerland) that is being investigated in the context of radioactive waste disposal. The study is targeted at the geomechanical characterization of shale by laboratory testing. The overall aim is to improve the constitutive mate...
Elastic anisotropy of shale is mainly controlled by the intrinsic anisotropy of individual clay minerals as well as by the textural alignment of grains, pores, and fractures. One of the major challenges in predicting the elastic anisotropy of shales, while using rock physics models, is that the elastic properties of rock-forming clay minerals are p...
: Many deep Earth mineral phases have stability fields that are accessible only with diamond anvil cell (DAC), and currently this remains the only method for studying these mineral phases at pressures relevant to the deep Earth. So far radial diffraction DAC experiments have had two serious limitations, pressure and stress could only be applied inc...