Hypothalamic dysfunction is an initial event following diet-induced obesity, primarily involving ... more Hypothalamic dysfunction is an initial event following diet-induced obesity, primarily involving areas regulating energy balance such as arcuate nucleus (Arc) and median eminence (ME). To gain insights into the early hypothalamic diet-induced alterations, adult CD1 mice fed a high-fat diet (HFD) for 6 weeks were studied and compared with normo-fed controls. Transmission and scanning electron microscopy and histological staining were employed for morphological studies of the ME, while Raman spectroscopy was applied for the biochemical analysis of the Arc-ME complex. In HFD mice, ME β2-tanycytes, glial cells dedicated to blood-liquor crosstalk, exhibited remarkable ultrastructural anomalies, including altered alignment, reduced junctions, degenerating organelles, and higher content of lipid droplets, lysosomes, and autophagosomes. Degenerating tanycytes also displayed an electron transparent cytoplasm filled with numerous vesicles, and they were surrounded by dilated extracellular spa...
The aim of the paper was to describe the advantages and disadvantages of the surgical adhesives m... more The aim of the paper was to describe the advantages and disadvantages of the surgical adhesives most useful in major cardiovascular surgery.
Stem cell-based therapeutics is a rapidly developing field associated with a number of clinical c... more Stem cell-based therapeutics is a rapidly developing field associated with a number of clinical challenges. One such challenge lies in the implementation of methods to track stem cells and stem cell-derived cells in experimental animal models and in the living patient. Here, we provide an overview of cell tracking in the context of cardiac and neurological disease, focusing on the use of iron oxide-based particles (IOPs) visualized in vivo using magnetic resonance imaging (MRI). We discuss the types of IOPs available for such tracking, their advantages and limitations, approaches for labeling cells with IOPs, biological interactions and effects of IOPs at the molecular and cellular levels, and MRI-based and associated approaches for in vivo and histological visualization. We conclude with reviews of the literature on IOP-based cell tracking in cardiac and neurological disease, covering both preclinical and clinical studies.
In the last decades, very significant advances have been made for what concerns bone and joint su... more In the last decades, very significant advances have been made for what concerns bone and joint substitution and in the repair and regeneration of bone defects. Though some strong requirements are still to be met, biomaterials for these purposes have known an impressive evolution, for what concerns their mechanical behaviour, their bioresorbability and finally their capability to generate new bone tissue in a stable way in long periods. The validation of such materials necessarily depends on a suitable characterization of their properties. In this article a brief review of some works in this field, carried out by the authors’ research group, is presented. It was shown in particular how advanced experimental methods, such as synchrotron radiation µCT and synchrotron radiation diffraction can offer very important information, can be not only complementary methods to more standard techniques (electron microscopy, X-ray diffraction), but can also offer the possibility to measure parameters that cannot be obtained otherwise.
Bioactivity investigations of titania nanotube (TNT) coatings enriched with silver nanograins (TN... more Bioactivity investigations of titania nanotube (TNT) coatings enriched with silver nanograins (TNT/Ag) have been carried out. TNT/Ag nanocomposite materials were produced by combining the electrochemical anodization and chemical vapor deposition methods. Fabricated coatings were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The release effect of silver ions from TNT/Ag composites immersed in bodily fluids, has been studied using inductively coupled plasma mass spectrometry (ICP-MS). The metabolic activity assay (MTT) was applied to determine the L929 murine fibroblasts adhesion and proliferation on the surface of TNT/Ag coatings. Moreover, the results of immunoassays (using peripheral blood mononuclear cells-PBMCs isolated from rats) allowed the estimation of the immunological activity of TNT/Ag surface materials. Antibacterial activity of TNT/Ag coatings with different morphological and structural features was estimated against two Staphylococcus aureus strains (ATCC 29213 and H9). The TNT/Ag nanocomposite layers produced revealed a good biocompatibility promoting the fibroblast adhesion and proliferation. A desirable anti-biofilm activity against the S. aureus reference strain was mainly noticed for these TiO 2 nanotube coatings, which contain dispersed Ag nanograins deposited on their surface.
Abstract The aim of the present study was to investigate the residual stress field in a steel gea... more Abstract The aim of the present study was to investigate the residual stress field in a steel gear cut and machined from extruded bars and then submitted to a case hardening surface treatment. Triaxial neutron diffraction measurements were carried out for residual stress ...
Using ultra-small angle neutron scattering method, we have analyzed sizes of pores of 100 nm-25 m... more Using ultra-small angle neutron scattering method, we have analyzed sizes of pores of 100 nm-25 mm in diameter in specimens from NiTi shape memory alloys produced by metal injection moulding before and after pulse electric current treatment. Such treatment invokes coalescence of pores with diameter smaller than 4 mm and size reduction of pores with diameter exceeding 4 mm.
A revolutionary discovery in the field of medical imaging occurred at the beginning of the 1970s ... more A revolutionary discovery in the field of medical imaging occurred at the beginning of the 1970s when the first equipment for X-rays Computed Tomography (CT) was developed. This method of imaging avoids several important limitations of conventional X-ray radiology. The impact of the CT technique has been revolutionary, enabling to view internal sample details with unprecedented precision and in a non-destructive way. Furthermore it achieves a contrast discrimination up to one thousand times better than conventional radiography . Tomography refers to the cross-sectional imaging of an object from either transmission or reflection data collected by illuminating the object from many different directions . Although the first application was in diagnostic medicine, there are indeed numerous nonmedical imaging applications. This methodology is applied to the mapping of underground resources via cross borehole imaging, to some specialized cases of crosssectional imaging for nondestructive testing, to the determination of the brightness distribution over a celestial sphere, to three-dimensional imaging with electron microscopy, etc. . Fundamentally, tomography employs X-rays to form images of objects based on their attenuation coefficient. Tomographic imaging deals with reconstructing an image from its projections. The solution to the problem of how to reconstruct a function from such projections dates back to the paper published by Radon in 1917 and it was exploited with Hounsfield's invention of the x-ray computed tomographic scanner for which the same Hounsfield received a Nobel prize in 1972. Given the enormous success of X-ray computed tomography, it is not surprising that in recent years much attention has been focused on extending this image formation technique to nuclear medicine and magnetic resonance, on one hand, and ultrasound and microwaves on the other . Computed X-ray microtomography (micro-CT) is similar to conventional CT systems usually employed in medical diagnoses and industrial applied research. Unlike these systems, which typically have a maximum spatial resolution of about 0.5 mm, advanced micro-CT is capable of achieving a spatial resolution up to 0.1 microns , i.e. about three orders of magnitude lower. Such a high spatial resolution can be obtained only for samples of reduced size i.e. for dimensions in the range of a few cubic millimeters. Synchrotron Radiation allows achieving high spatial resolution images to be generated with high signal-to-noise ratio . Use of Xrays delivered by Synchrotron Facilities has several advantages compared to X-rays produced by Laboratory or Industrial sources. These include: (i) a high photon flux which permits measurements at high spatial resolution; (ii) the X-ray source is tunable, thus allowing measurements at different energies; (iii) the X-ray radiation is monochromatic, which eliminates beam hardening effects; and (iv) parallel beam acquisition allows the use of exact tomographic reconstruction algorithms. In addition, Synchrotron Radiation allows acquisition of volumes at different energies and volume subtraction to enhance contrast. Because of this variability, it is possible to enables digital image processing of micro-CT data in order to maximize contrast between neighboring voxels in the image and to increase the range of attenuation values of the entire volume. This variability in materials and acquisition methods leads to a wide range of grayscale values (corresponding to different Xray absorption coefficients) within and among data sets .
True Baroque organ music can only come back to life in the 21st century by developing Cu-based al... more True Baroque organ music can only come back to life in the 21st century by developing Cu-based alloys and implementing them in the organ reed pipes. Reed pipes contain a vibrating part, the brass tongue that crucially influences its sound. Energy dispersive synchrotron X-ray diffraction has been performed in order to investigate residual stresses in the tongues. The in depth analysis gives us an important indication on the processes the tongues were submitted to during their manufacturing: hammering, annealing, filing to the neat thickness, curving of the tongues. A biaxial stress state in the organ tongues was considered. The residual stress values and behaviour were correlated to the manufacturing processes.
Page 1. A new method based on hard x-ray diffraction for the investigation of archaeological arte... more Page 1. A new method based on hard x-ray diffraction for the investigation of archaeological artefacts This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2006 Meas. Sci. Technol. 17 L1 (http://iopscience.iop.org/0957-0233/17/4/L01) ...
Stem cell based tissue engineering therapies involve the administration of ex vivo manipulated st... more Stem cell based tissue engineering therapies involve the administration of ex vivo manipulated stem cell populations with the purpose of repairing and regenerating damaged or diseased tissue. Currently available methods of monitoring transplanted cells are quite limited. To monitor the outcomes of stem cell therapy longitudinally requires the development of non-destructive strategies that are capable of identifying the location, magnitude, and duration of cellular survival and fate. The recent development of imaging techniques offers great potential to address these critical issues by non-invasively tracking the fate of the transplanted cells. This review offers a focused presentation of some examples of the use of imaging techniques connected to the nanotechnological world in research areas related to stem cells. In particular investigations will be considered concerning tissue-engineered bone, treatment of intervertebral disc degeneration, treatment by human stem cells of muscular dystrophy of Duchenne in small animal models and the repair of spinal cord injuries.
In order to be able to reproduce historic organ reed pipes, a bulk non-destructive chemical compo... more In order to be able to reproduce historic organ reed pipes, a bulk non-destructive chemical composition analysis was performed on the tongues and shallots, focusing mainly on the ratio between copper and zinc and on the presence of lead. Prompt gamma activation analysis results allowed us to observe for the first time that the ratio between the two main components of the brass alloy changed from Cu:Zn = 3:1 for the old tongues and shallots to Cu:Zn = 2:1 around the middle of the 18th century, which is typical also for the modern alloys offered to the organ builders nowadays. We also discovered that the Pb content in the old historic brass alloy diminished until the middle of 18th century when the brass alloy became mainly Pb free. The non-uniform lead distribution inside one of the shallots obtained from a prompt gamma activation analysis (PGAA) experiment was studied by neutron tomography. It gave us a three-dimensonal (3D) distribution of the lead inclusions inside the shallots. The lead particles are concentrated towards the base of the shallot.
Results are presented of a small-angle neutron scattering (SANS) study on two 10-13% Cr martensit... more Results are presented of a small-angle neutron scattering (SANS) study on two 10-13% Cr martensitic stainless steels of interest for nuclear applications, viz. DIN 1.4914 (MANET specification, for fusion reactors) and AISI 410. The investigation has focussed principally on microstructural effects associated with the differences in chromium content between the two alloys. The size distribution functions determined from nuclear and magnetic SANS components for the two steels given identical heat treatments are in accord with an interpretation based on the presence of ~ 1 nm size C-Cr aggregates in the microstructure. Much larger ( ~ 10 nm) scattering inhomogeneities with different magnetic contrast are also present and tentatively identified as carbides.
The residual stresses in a component for automotive industry, a wheel hub made of composite mater... more The residual stresses in a component for automotive industry, a wheel hub made of composite material, are investigated. Forged AA6061 þ Al2O3 hubs of identical shape and dimensions submitted to different thermal treatments are considered. The effects of T6 and T6-special treatments are compared. A reference forged sample without thermal treatments is also studied. Results are checked and compared with those previously obtained in simple shape demonstrators submitted to the same thermal treatments. Particular attention is given to the stresses along the radial and hoop directions, as they are expected to be critical for what concerns the in-service life of that component.
Within the last decade neutron tomography and radiography significantly gained importance. Especi... more Within the last decade neutron tomography and radiography significantly gained importance. Especially its application in non-destructive testing for industrial components can be underlined. A good example is the automotive and aviation industry, where a high contrast for the used lubricants and adhesive materials is required. In contrast to X-rays, neutrons are able to penetrate thick layers of metals and provide on the other hand a high sensitivity to hydrogen containing materials. In recent years a large number of applications in other fields like biology, medicine, geology and especially archaeology have been reported. Here the potential of neutron tomography for investigations on archaeological samples shall be lined out and some recent examples will be presented.
Neutron and synchrotron radiation techniques are very powerful non-destructive methods for the ch... more Neutron and synchrotron radiation techniques are very powerful non-destructive methods for the characterisation of a wide variety of materials. In particular, neutron and synchrotron radiation diffraction is nowadays widely used for the evaluation of residual stresses induced by thermal and mechanical treatments in materials and components for industrial applications. By small angle neutron scattering (SANS), microstructural features induced by thermomechanical treatments, such as precipitation and cavitation, can be investigated from a quantitative point of view (determination of size distributions, volume fraction). A review is presented of the techniques mentioned above, and some applications to materials for technological applications will be presented.
The crystal fabric of a lava has been analyzed for the first time by neutron texture diffraction.... more The crystal fabric of a lava has been analyzed for the first time by neutron texture diffraction. In this study we quantitatively investigate the crystallographic preferred orientation of feldspars in the Castello d'Ischia (Ischia Island, Italy) trachytic exogenous dome. The crystallographic preferred orientation was measured with the monochromatic neutron texture diffractometer SV7 at the Forschungszentrum Jülich in Germany and a Rietveld refinement was applied to the sum diffraction pattern. The complementary thin section analysis showed that the three‐dimensional crystal shape and the corresponding shape preferred orientation are in agreement with the quantitative orientation distributions of the neutron texture data. The (0k0) crystallographic planes of the feldspars are roughly parallel to the local flow bands, whereas the other corresponding pole figures show that a pivotal rotation of the anorthoclase and sanidine crystals was active during the emplacement of this lava do...
Hypothalamic dysfunction is an initial event following diet-induced obesity, primarily involving ... more Hypothalamic dysfunction is an initial event following diet-induced obesity, primarily involving areas regulating energy balance such as arcuate nucleus (Arc) and median eminence (ME). To gain insights into the early hypothalamic diet-induced alterations, adult CD1 mice fed a high-fat diet (HFD) for 6 weeks were studied and compared with normo-fed controls. Transmission and scanning electron microscopy and histological staining were employed for morphological studies of the ME, while Raman spectroscopy was applied for the biochemical analysis of the Arc-ME complex. In HFD mice, ME β2-tanycytes, glial cells dedicated to blood-liquor crosstalk, exhibited remarkable ultrastructural anomalies, including altered alignment, reduced junctions, degenerating organelles, and higher content of lipid droplets, lysosomes, and autophagosomes. Degenerating tanycytes also displayed an electron transparent cytoplasm filled with numerous vesicles, and they were surrounded by dilated extracellular spa...
The aim of the paper was to describe the advantages and disadvantages of the surgical adhesives m... more The aim of the paper was to describe the advantages and disadvantages of the surgical adhesives most useful in major cardiovascular surgery.
Stem cell-based therapeutics is a rapidly developing field associated with a number of clinical c... more Stem cell-based therapeutics is a rapidly developing field associated with a number of clinical challenges. One such challenge lies in the implementation of methods to track stem cells and stem cell-derived cells in experimental animal models and in the living patient. Here, we provide an overview of cell tracking in the context of cardiac and neurological disease, focusing on the use of iron oxide-based particles (IOPs) visualized in vivo using magnetic resonance imaging (MRI). We discuss the types of IOPs available for such tracking, their advantages and limitations, approaches for labeling cells with IOPs, biological interactions and effects of IOPs at the molecular and cellular levels, and MRI-based and associated approaches for in vivo and histological visualization. We conclude with reviews of the literature on IOP-based cell tracking in cardiac and neurological disease, covering both preclinical and clinical studies.
In the last decades, very significant advances have been made for what concerns bone and joint su... more In the last decades, very significant advances have been made for what concerns bone and joint substitution and in the repair and regeneration of bone defects. Though some strong requirements are still to be met, biomaterials for these purposes have known an impressive evolution, for what concerns their mechanical behaviour, their bioresorbability and finally their capability to generate new bone tissue in a stable way in long periods. The validation of such materials necessarily depends on a suitable characterization of their properties. In this article a brief review of some works in this field, carried out by the authors’ research group, is presented. It was shown in particular how advanced experimental methods, such as synchrotron radiation µCT and synchrotron radiation diffraction can offer very important information, can be not only complementary methods to more standard techniques (electron microscopy, X-ray diffraction), but can also offer the possibility to measure parameters that cannot be obtained otherwise.
Bioactivity investigations of titania nanotube (TNT) coatings enriched with silver nanograins (TN... more Bioactivity investigations of titania nanotube (TNT) coatings enriched with silver nanograins (TNT/Ag) have been carried out. TNT/Ag nanocomposite materials were produced by combining the electrochemical anodization and chemical vapor deposition methods. Fabricated coatings were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The release effect of silver ions from TNT/Ag composites immersed in bodily fluids, has been studied using inductively coupled plasma mass spectrometry (ICP-MS). The metabolic activity assay (MTT) was applied to determine the L929 murine fibroblasts adhesion and proliferation on the surface of TNT/Ag coatings. Moreover, the results of immunoassays (using peripheral blood mononuclear cells-PBMCs isolated from rats) allowed the estimation of the immunological activity of TNT/Ag surface materials. Antibacterial activity of TNT/Ag coatings with different morphological and structural features was estimated against two Staphylococcus aureus strains (ATCC 29213 and H9). The TNT/Ag nanocomposite layers produced revealed a good biocompatibility promoting the fibroblast adhesion and proliferation. A desirable anti-biofilm activity against the S. aureus reference strain was mainly noticed for these TiO 2 nanotube coatings, which contain dispersed Ag nanograins deposited on their surface.
Abstract The aim of the present study was to investigate the residual stress field in a steel gea... more Abstract The aim of the present study was to investigate the residual stress field in a steel gear cut and machined from extruded bars and then submitted to a case hardening surface treatment. Triaxial neutron diffraction measurements were carried out for residual stress ...
Using ultra-small angle neutron scattering method, we have analyzed sizes of pores of 100 nm-25 m... more Using ultra-small angle neutron scattering method, we have analyzed sizes of pores of 100 nm-25 mm in diameter in specimens from NiTi shape memory alloys produced by metal injection moulding before and after pulse electric current treatment. Such treatment invokes coalescence of pores with diameter smaller than 4 mm and size reduction of pores with diameter exceeding 4 mm.
A revolutionary discovery in the field of medical imaging occurred at the beginning of the 1970s ... more A revolutionary discovery in the field of medical imaging occurred at the beginning of the 1970s when the first equipment for X-rays Computed Tomography (CT) was developed. This method of imaging avoids several important limitations of conventional X-ray radiology. The impact of the CT technique has been revolutionary, enabling to view internal sample details with unprecedented precision and in a non-destructive way. Furthermore it achieves a contrast discrimination up to one thousand times better than conventional radiography . Tomography refers to the cross-sectional imaging of an object from either transmission or reflection data collected by illuminating the object from many different directions . Although the first application was in diagnostic medicine, there are indeed numerous nonmedical imaging applications. This methodology is applied to the mapping of underground resources via cross borehole imaging, to some specialized cases of crosssectional imaging for nondestructive testing, to the determination of the brightness distribution over a celestial sphere, to three-dimensional imaging with electron microscopy, etc. . Fundamentally, tomography employs X-rays to form images of objects based on their attenuation coefficient. Tomographic imaging deals with reconstructing an image from its projections. The solution to the problem of how to reconstruct a function from such projections dates back to the paper published by Radon in 1917 and it was exploited with Hounsfield's invention of the x-ray computed tomographic scanner for which the same Hounsfield received a Nobel prize in 1972. Given the enormous success of X-ray computed tomography, it is not surprising that in recent years much attention has been focused on extending this image formation technique to nuclear medicine and magnetic resonance, on one hand, and ultrasound and microwaves on the other . Computed X-ray microtomography (micro-CT) is similar to conventional CT systems usually employed in medical diagnoses and industrial applied research. Unlike these systems, which typically have a maximum spatial resolution of about 0.5 mm, advanced micro-CT is capable of achieving a spatial resolution up to 0.1 microns , i.e. about three orders of magnitude lower. Such a high spatial resolution can be obtained only for samples of reduced size i.e. for dimensions in the range of a few cubic millimeters. Synchrotron Radiation allows achieving high spatial resolution images to be generated with high signal-to-noise ratio . Use of Xrays delivered by Synchrotron Facilities has several advantages compared to X-rays produced by Laboratory or Industrial sources. These include: (i) a high photon flux which permits measurements at high spatial resolution; (ii) the X-ray source is tunable, thus allowing measurements at different energies; (iii) the X-ray radiation is monochromatic, which eliminates beam hardening effects; and (iv) parallel beam acquisition allows the use of exact tomographic reconstruction algorithms. In addition, Synchrotron Radiation allows acquisition of volumes at different energies and volume subtraction to enhance contrast. Because of this variability, it is possible to enables digital image processing of micro-CT data in order to maximize contrast between neighboring voxels in the image and to increase the range of attenuation values of the entire volume. This variability in materials and acquisition methods leads to a wide range of grayscale values (corresponding to different Xray absorption coefficients) within and among data sets .
True Baroque organ music can only come back to life in the 21st century by developing Cu-based al... more True Baroque organ music can only come back to life in the 21st century by developing Cu-based alloys and implementing them in the organ reed pipes. Reed pipes contain a vibrating part, the brass tongue that crucially influences its sound. Energy dispersive synchrotron X-ray diffraction has been performed in order to investigate residual stresses in the tongues. The in depth analysis gives us an important indication on the processes the tongues were submitted to during their manufacturing: hammering, annealing, filing to the neat thickness, curving of the tongues. A biaxial stress state in the organ tongues was considered. The residual stress values and behaviour were correlated to the manufacturing processes.
Page 1. A new method based on hard x-ray diffraction for the investigation of archaeological arte... more Page 1. A new method based on hard x-ray diffraction for the investigation of archaeological artefacts This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2006 Meas. Sci. Technol. 17 L1 (http://iopscience.iop.org/0957-0233/17/4/L01) ...
Stem cell based tissue engineering therapies involve the administration of ex vivo manipulated st... more Stem cell based tissue engineering therapies involve the administration of ex vivo manipulated stem cell populations with the purpose of repairing and regenerating damaged or diseased tissue. Currently available methods of monitoring transplanted cells are quite limited. To monitor the outcomes of stem cell therapy longitudinally requires the development of non-destructive strategies that are capable of identifying the location, magnitude, and duration of cellular survival and fate. The recent development of imaging techniques offers great potential to address these critical issues by non-invasively tracking the fate of the transplanted cells. This review offers a focused presentation of some examples of the use of imaging techniques connected to the nanotechnological world in research areas related to stem cells. In particular investigations will be considered concerning tissue-engineered bone, treatment of intervertebral disc degeneration, treatment by human stem cells of muscular dystrophy of Duchenne in small animal models and the repair of spinal cord injuries.
In order to be able to reproduce historic organ reed pipes, a bulk non-destructive chemical compo... more In order to be able to reproduce historic organ reed pipes, a bulk non-destructive chemical composition analysis was performed on the tongues and shallots, focusing mainly on the ratio between copper and zinc and on the presence of lead. Prompt gamma activation analysis results allowed us to observe for the first time that the ratio between the two main components of the brass alloy changed from Cu:Zn = 3:1 for the old tongues and shallots to Cu:Zn = 2:1 around the middle of the 18th century, which is typical also for the modern alloys offered to the organ builders nowadays. We also discovered that the Pb content in the old historic brass alloy diminished until the middle of 18th century when the brass alloy became mainly Pb free. The non-uniform lead distribution inside one of the shallots obtained from a prompt gamma activation analysis (PGAA) experiment was studied by neutron tomography. It gave us a three-dimensonal (3D) distribution of the lead inclusions inside the shallots. The lead particles are concentrated towards the base of the shallot.
Results are presented of a small-angle neutron scattering (SANS) study on two 10-13% Cr martensit... more Results are presented of a small-angle neutron scattering (SANS) study on two 10-13% Cr martensitic stainless steels of interest for nuclear applications, viz. DIN 1.4914 (MANET specification, for fusion reactors) and AISI 410. The investigation has focussed principally on microstructural effects associated with the differences in chromium content between the two alloys. The size distribution functions determined from nuclear and magnetic SANS components for the two steels given identical heat treatments are in accord with an interpretation based on the presence of ~ 1 nm size C-Cr aggregates in the microstructure. Much larger ( ~ 10 nm) scattering inhomogeneities with different magnetic contrast are also present and tentatively identified as carbides.
The residual stresses in a component for automotive industry, a wheel hub made of composite mater... more The residual stresses in a component for automotive industry, a wheel hub made of composite material, are investigated. Forged AA6061 þ Al2O3 hubs of identical shape and dimensions submitted to different thermal treatments are considered. The effects of T6 and T6-special treatments are compared. A reference forged sample without thermal treatments is also studied. Results are checked and compared with those previously obtained in simple shape demonstrators submitted to the same thermal treatments. Particular attention is given to the stresses along the radial and hoop directions, as they are expected to be critical for what concerns the in-service life of that component.
Within the last decade neutron tomography and radiography significantly gained importance. Especi... more Within the last decade neutron tomography and radiography significantly gained importance. Especially its application in non-destructive testing for industrial components can be underlined. A good example is the automotive and aviation industry, where a high contrast for the used lubricants and adhesive materials is required. In contrast to X-rays, neutrons are able to penetrate thick layers of metals and provide on the other hand a high sensitivity to hydrogen containing materials. In recent years a large number of applications in other fields like biology, medicine, geology and especially archaeology have been reported. Here the potential of neutron tomography for investigations on archaeological samples shall be lined out and some recent examples will be presented.
Neutron and synchrotron radiation techniques are very powerful non-destructive methods for the ch... more Neutron and synchrotron radiation techniques are very powerful non-destructive methods for the characterisation of a wide variety of materials. In particular, neutron and synchrotron radiation diffraction is nowadays widely used for the evaluation of residual stresses induced by thermal and mechanical treatments in materials and components for industrial applications. By small angle neutron scattering (SANS), microstructural features induced by thermomechanical treatments, such as precipitation and cavitation, can be investigated from a quantitative point of view (determination of size distributions, volume fraction). A review is presented of the techniques mentioned above, and some applications to materials for technological applications will be presented.
The crystal fabric of a lava has been analyzed for the first time by neutron texture diffraction.... more The crystal fabric of a lava has been analyzed for the first time by neutron texture diffraction. In this study we quantitatively investigate the crystallographic preferred orientation of feldspars in the Castello d'Ischia (Ischia Island, Italy) trachytic exogenous dome. The crystallographic preferred orientation was measured with the monochromatic neutron texture diffractometer SV7 at the Forschungszentrum Jülich in Germany and a Rietveld refinement was applied to the sum diffraction pattern. The complementary thin section analysis showed that the three‐dimensional crystal shape and the corresponding shape preferred orientation are in agreement with the quantitative orientation distributions of the neutron texture data. The (0k0) crystallographic planes of the feldspars are roughly parallel to the local flow bands, whereas the other corresponding pole figures show that a pivotal rotation of the anorthoclase and sanidine crystals was active during the emplacement of this lava do...
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Papers by Fabrizio Fiori