Franco Zanini

Three-dimensional investigation of volcanic textures by X-ray microtomography and implications for conduit processes

[1] Synchrotron X-ray computed microtomography (μCT) was applied for the first time to clasts of pumice and scoria generated by active, explosive volcanoes characterized by a range of eruptive styles (mild Strombolian to Plinian) and magmatic composition (basaltic to trachytic). The obtained two-dimensional (2D) tomographic images, corresponding to sample views at different rotation angles, were processed to reconstruct three-dimensional (3D) volumes and then used to make 3D measurements of vesicularity, vesicle number density, volume and connectivity for quantitative characterization of the investigated tephras. The results indicate a positive correlation between vesicle number density and eruption intensity that is used to investigate modes of magma degassing in explosive eruptions. In addition, the vesicle geometry affecting the connected gas flow pathways in pyroclasts from Strombolian eruptions is determined and related to the known permeabilities. Implications on the dynamics of explosive eruptions is discussed and, ultimately, used to quantitatively discriminate between different eruptive styles.

Imaging Techniques for the Study of Food Microstructure: A Review

Publisher Summary This chapter presents a review on imaging techniques for the study of food microstructure. The quality of a food product is related to its sensorial—shape, size, color, and mechanical (texture) characteristics. These features are strongly affected by the food structural organization that can be studied at molecular, microscopic, and macroscopic levels. In particular, the microstructure and interactions of components, such as protein, starch, and fat, determine the texture of a food that could be defined as the ‘‘external manifestation of this structure.’’ Because the microstructure affects food sensorial properties, foods having a similar microstructure also have a similar behavior. Studies on food microstructure can be performed by means of a large variety of techniques allowing the generation of data in the form of images. With the development of more powerful tools, such as the X-ray-computed tomographic scanners, both 2D and 3D digital images of the food internal structure can be readily acquired with high resolution and contrast and without any sample preparation. These images can be processed by means of the fractal and stereological analysis to quantify a number of structural elements. Fractal analysis allows the investigation of the fractal geometry in both 2D and 3D digital images.

Evaluation of Microstructural Properties of Coffee Beans by Synchrotron X-Ray Microtomography: A Methodological Approach

UNLABELLED 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 characterize the morphological and structural features of the coffee beans. Roasting causes meaningful changes in the microstructure of the coffee bean tissue with the development in the entire bean of a porous structure with pores of different shape and size depending on the zone of the bean and cracks occurring mainly in the more external regions and between parenchyma and mucilage. The highly contrasted X-ray images have been analyzed to determine the pore size and its distribution in different regions of the coffee beans by selecting Volume-of-Interest (VoI). The use of phase-contrast hard X-rays imaging techniques represents an interesting tool of investigation of the internal structure, morphology, as well as the quality of whole coffee beans. Moreover, the high potentiality of 3D X-ray imaging and the approach used in this study could be applied in understanding the effects of roasting process conditions on the evolution of microstructural properties of the bean that may affect the stability as well the grinding and brewing performances. PRACTICAL APPLICATION Synchrotron radiation microtomography is an elegant nondestructive imaging technique to investigate the microstructural properties of porous cellular matrices like the green and roasted coffee beans. The quantitative analysis of the resulting 2D and 3D images allows a more comprehensive and objective characterization of the sample under investigation as a whole or of extracted Volumes-of-Interest in the bean. This imaging technique could have a major role in understanding the effects of roasting process conditions on the microstructural properties of the bean.

Improving FTIR imaging speciation of organic compound residues or their degradation products in wall painting samples, by introducing a new thin section preparation strategy based on cyclododecane pre-treatment

AbstractFourier transform infrared (FTIR) imaging in transmission mode, employing a bidimensional focal plane array (FPA) detector, was applied for the detection and spatially resolved chemical characterisation of organic compounds or their degradation products within the stratigraphy of a critical group of fragments, originating from prehistoric and roman wall paintings, containing a very low concentration of subsisted organic matter or its alteration products. Past analyses using attenuated total reflection (ATR) or reflection FTIR on polished cross sections failed to provide any evidence of any organic material assignable as binding medium of the original painting. In order to improve the method’s performance, in the present study, a new method of sample preparation in thin section was developed. The procedure is based on the use of cyclododecane C12H24 as embedding material and a subsequent double-side polishing of the specimen. Such procedure provides samples to be studied in FTIR transmission mode without losing the information on the spatial distribution of the detected materials in the paint stratigraphy. For comparison purposes, the same samples were also studied after opening their stratigraphy with a diamond anvil cell. Both preparation techniques offered high-quality chemical imaging of the decay products of an organic substance, giving clues to the painting technique. In addition, the thin sections resulting from the cyclododecane pre-treatment offered more layer-specific data, as the layer thickness and order remained unaffected, whereas the samples resulting from compression within the diamond cell were slightly deformed; however, since thinner and more homogenous, they provided higher spectral quality in terms of S/N ratio. In summary, the present study illustrates the appropriateness of FTIR imaging in transmission mode associated with a new thin section preparation strategy to detect and localise very low-concentrated organic matter subjected to deterioration processes, when the application of FTIR in reflection mode or FTIR-ATR fails to give any relevant information. Graphical AbstractVisible image of a thin section, C12H24 pre-treated, originating from prehistoric wall paintings at Akrotiri, Thera (Greece). FTIR images representing the spatial distribution of the consolidant, the minerals: wollastonite, riebeckite, and a proteinaceous binder. The size of the FTIR images is 170 × 340 μm2

A synchrotron radiation microprobe for X-ray fluorescence and microtomography at ELETTRA. Focusing with bent crystals

Abstract An X-ray fluorescence microprobe utilizing the radiation from a bending magnet of ELETTRA, the high-brilliance synchrotron radiation source being built in Trieste, has been proposed. Various focusing monochromators have been considered in order to produce a micron-size beam. Here we use ray-tracing programs to estimate the X-ray fluxes obtainable at ELETTRA with a bent crystal. The performance of the microprobe for trace-element analysis and computed tomography of microscopic biological specimens is also presented.

A synchrotron radiation microprobe for X-ray fluorescence and microtomography at ELETTRA

Abstract A synchrotron radiation microscope based on X-ray fluorescence and computed microtomography for advanced applications in biomedicine, environmental sciences, geology and materials science is described. This microscope will utilize the radiation produced by a bending magnet of ELETTRA, the third-generation, high-brilliance synchrotron radiation facility being built in Trieste. Various wide-band-pass mirror systems operating in an energy range between 7 and 17 keV have been designed. For example, multilayer-coated mirrors in the Kirkpatrick-Baez configuration can produce a spatial resolution of 1 μm2 for a flux in excess of 108 photons per second on the sample (E = 12 keV, E ΔE = 10 ). This X-ray microprobe will allow micrometric mapping of trace and minor elements and computed tomographic imaging with high resolution, opening a new realm of experiments in different fields of science, such as in vivo elemental scanning and microtomography of cultured cells, analysis of single atmospheric particulates, analysis of cosmic debris collected from the stratosphere and antarctic ice, etc. The preliminary design of the beam line and the performance of the microprobe are discussed.

Non-invasive wood identification of historical musical bows

We identified the wood of the sticks of eight bows in the historical collection of musical instruments in the Galleria dell’ Accademia in Florence. Wood identification was carried out non-invasively (i.e., without sampling wood from the original objects), because the removal of samples from fine musical instruments will affect their aesthetic integrity and/or functional quality. Identification attempts using reflected light microscopy of wood surfaces, gave only partial results due to the poor quality of the surfaces and the particular geometry of the sticks that does not have any transverse surface. Application of Synchrotron light X-ray microtomography (µCT) in phase-contrast mode to the whole sticks allowed us to obtain stacks of transverse-sectional images that, processed as virtual volumes, revealed several anatomical features. With µCT it was possible to identify three bows as Brosimum guianense (Moraceae), one bow as Caesalpinia echinata (Caesalpiniaceae), and four bows as Manilkara sp. (Sapotaceae).

Imaging using synchrotron radiation for forensic science

Forensic science is already taking benefits from synchrotron radiation (SR) sources in trace evidence analysis. In this contribution we show a multi-technique approach to study fingerprints from the morphological and chemical point of view using SR based techniques such as Fourier transform infrared microspectroscopy (FTIRMS), X-ray fluorescence (XRF), X-ray absorption structure (XAS), and phase contrast microradiography. Both uncontaminated and gunshot residue contaminated human fingerprints were deposited on lightly doped silicon wafers and on poly-ethylene-terephthalate foils. For the uncontaminated fingerprints an univariate approach of functional groups mapping to model FT-IRMS data was used to get the morphology and the organic compounds map. For the gunshot residue contaminated fingerprints, after a preliminary elemental analysis using XRF, microradiography just below and above the absorption edge of the elements of interest has been used to map the contaminants within the fingerprint. Finally, XAS allowed us to determine the chemical state of the different elements. The next step will be fusing the above information in order to produce an exhaustive and easily understandable evidence.

Wavelength spread of doubly bent crystals for X-ray microfocusing applications

Abstract Synchrotron radiation from third generation, high-brilliance rings is an ideal source for X-ray microbeams. The aim of the present article is to discuss properties of bent crystals used as focusing optical elements designed to obtain micron-size photon spots with high intensity and wide bandpass monochromatization. In particular, simple mathematical expressions are derived for the energy bandpass of a strongly demagnifying doubly bent crystal, where the contribution from the sagittal curvature is particularly important.

Virtual histological assessment of the prenatal life history and age at death of the Upper Paleolithic fetus from Ostuni (Italy)

The fetal remains from the Ostuni 1 burial (Italy, ca 27 ka) represent a unique opportunity to explore the prenatal biological parameters, and to reconstruct the possible patho-biography, of a fetus (and its mother) in an Upper Paleolithic context. Phase-contrast synchrotron X-ray microtomography imaging of two deciduous tooth crowns and microfocus CT measurements of the right hemimandible of the Ostuni 1b fetus were performed at the SYRMEP beamline and at the TomoLab station of the Elettra - Sincrotrone laboratory (Trieste, Italy) in order to refine age at death and to report the enamel developmental history and dental tissue volumes for this fetal individual. The virtual histology allowed to estimate the age at death of the fetus at 31–33 gestational weeks. Three severe physiological stress episodes were also identified in the prenatal enamel. These stress episodes occurred during the last two months and half of pregnancy and may relate to the death of both individuals. Compared with modern prenatal standards, Os1b’s skeletal development was advanced. This cautions against the use of modern skeletal and dental references for archaeological finds and emphasizes the need for more studies on prenatal archaeological skeletal samples.