Luca Lutterotti
University of Trento, Industrial Engineering, Faculty Member
In this work a streamline characterization protocol for debris coming from wear tests on materials used for disc brake assemblies is presented. An important aspect of the methodology concerns powder collection involving aluminum foil,for... more
In this work a streamline characterization protocol for debris coming from wear tests on materials used
for disc brake assemblies is presented. An important aspect of the methodology concerns powder collection involving aluminum foil,for a gravitational collection,and poly carbonate filters of an impactor, on which particles are selectively trapped, according to their size. The protocol is based on
the application of scanning and transmission electron microscopy,X-ray spectroscopy,X-ray and
selected area electron diffraction.The aim of the study was to identify selection parameters,like
specimen availability and average particle size,for an effective and smart application of the techniques.
for disc brake assemblies is presented. An important aspect of the methodology concerns powder collection involving aluminum foil,for a gravitational collection,and poly carbonate filters of an impactor, on which particles are selectively trapped, according to their size. The protocol is based on
the application of scanning and transmission electron microscopy,X-ray spectroscopy,X-ray and
selected area electron diffraction.The aim of the study was to identify selection parameters,like
specimen availability and average particle size,for an effective and smart application of the techniques.
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There is a critical need for optoelectronic devices optimization to give quantitative chemical composition measurement of these materials with buried interfaces and with nanometer depth resolution. Grazing-incidence X-Ray Fluorescence... more
There is a critical need for optoelectronic devices optimization to give quantitative chemical composition measurement of these materials with buried interfaces and with nanometer depth resolution. Grazing-incidence X-Ray Fluorescence (GIXRF) is a new technique that offers the potential to substantially provide high sensitivity to investigate surface or buried interface contamination as well as elemental depth-profiling capabilities. In combination with X-Ray Reflectometry (XRR), this method will also allow for depth resolved material characterization with resolution in the nanometer range. Moreover, as sometimes the polycrystalline studied films exhibiting also preferential orientations, these two techniques can be also coupled with X-Ray quantitative texture measurements (XRD). For the first time, on transparent conducting oxides multilayered samples for photovoltaic applications, using the new developed combined GIXRF-XRR-XRD analysis approach (through the MAUD program) we have d...
The 11-years old methodology called Combined Analysis using rays (x-rays, neutrons, electrons) has proved its efficiency in particular in treating QTA from diffraction spectra using x-rays, neutrons and electrons. Its success concerning... more
The 11-years old methodology called Combined Analysis using rays (x-rays, neutrons, electrons) has proved its efficiency in particular in treating QTA from diffraction spectra using x-rays, neutrons and electrons. Its success concerning QTA summarises as three main points: - it avoids tricky data reductions and corrections, that depend on more or less uncontrolled parameters, these latter becoming fitted parameters that are then better estimated - it solves the difficult overlapping peaks problem (intra- and interphases), with the use of an extended Rietveld approach - it includes the determination of other important quantities, like residual stresses, crystal sizes and microstrains, structures ... Not only Combined Analysis avoids false minima in the refinements when e.g. texture or structure is the only targeted aspect, but it also allows to benefit from anisotropies in real samples rather than to suffer for them during characterizations. We will show that Combined Analysis can be...
The 10-years old methodology called Combined Analysis using rays (x-rays, neutrons, electrons) has proved its efficiency in particular in the field of thin architectures characterization and real materials. Not only it avoids false minima... more
The 10-years old methodology called Combined Analysis using rays (x-rays, neutrons, electrons) has proved its efficiency in particular in the field of thin architectures characterization and real materials. Not only it avoids false minima in the refinements when e.g. texture or structure is the only targeted aspect, but it also allows to benefit from anisotropies in real samples rather than to suffer for them during characterizations. We illustrate in this presentation: - the quantitative determinations of texture, microstructure (anisotropic nanocrystal sizes and microstrains), structure, residual stresses, phases on complex examples of thin structured layers using x-ray diffraction, - the actual developments of the methodology, noticeably concerning the use of TEM Debye- ring patterns - some milestones about the future developments
Crystallites with sizes down to one or several unit-cells give rise to strongly broadened diffraction lines, often discouraging any quantitative treatment of the patterns. Full-profile analysis of these patterns obtained from nanopowders... more
Crystallites with sizes down to one or several unit-cells give rise to strongly broadened diffraction lines, often discouraging any quantitative treatment of the patterns. Full-profile analysis of these patterns obtained from nanopowders however still offers quantitative characterization, provided a robust implementation of crystallite sizes and shapes is operated. Rietveld analysis combined to shape modelling by spherical harmonics as proposed by the Popa approach is used in this work. It proved to allow discrimination between two closely related zeolite phases, namely FAU and EMT, obtained as nanopowders using a specific technique. Mean crystallites not larger than 2 unit-cells of EMT could be quantified using laboratory XRD. In cases for which not enough powders could be obtained, i.e. for which XRD signal becomes too small, we used an equivalent approach on TEM ring patterns. In this latter case only small powder volumes are required and the large TEM signal becomes advantageous...
L. LUTTEROTTI Department of Geology and Geophysics, University of California, 94720 Berkeley, California, USA; Dipartimento di Ingegneria dei Materiali, Universit `a di Trento, 38050 Trento, Italy ... HR WENK∗, F. KOVACS Department of... more
L. LUTTEROTTI Department of Geology and Geophysics, University of California, 94720 Berkeley, California, USA; Dipartimento di Ingegneria dei Materiali, Universit `a di Trento, 38050 Trento, Italy ... HR WENK∗, F. KOVACS Department of Geology and Geophysics, ...
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The project: Combined analysis: state of the art (already assessed) Combined analysis: actual work (under testing) • Energy minimization / DFT (Density Functional Theory) • Debye/PDF (Pair Distribution Function) • X-ray fluorescence, EDXS... more
The project: Combined analysis: state of the art (already assessed) Combined analysis: actual work (under testing) • Energy minimization / DFT (Density Functional Theory) • Debye/PDF (Pair Distribution Function) • X-ray fluorescence, EDXS • Magnetic structure/texture • Dynamical scattering (electron) Deformation textures produced in diamond anvil experiments, analysed in radial diffraction geometry S937 Figure 4. Rietveld method applied to diffraction image of perovskite (figure 2(a)). (a) Two experimental and fitted spectra parallel (top) and perpendicular to compression direction (bottom). (b) Map plot of stacked normalized spectra, experimental at bottom and calculated at top. Compression direction indicated by arrow. diffraction lines and the deviations between experiment and fit. The two spectra correspond to different slices and represent different orientations relative to the compression direction. In the spectrum on top the lattice planes are perpendicular to the compression...
The air quality is one of the major concerns for health. There is a need for continuous monitoring of the particulate especially in the submicron range. XRD is one of the principal techniques for the analysis of powders and fundamental to... more
The air quality is one of the major concerns for health. There is a need for continuous monitoring of the particulate especially in the submicron range. XRD is one of the principal techniques for the analysis of powders and fundamental to identify dangerous products. An European project named Nanoair has been concluded successfully which aim was to develop a mobile instrument for qualitative and quantitative analysis of breathable particles. The instrument uses XRD and SAXS for the characterization of the automatically collected samples.
Crystallography Open Database (COD, http://www.crystallography.net) is the largest to date curated open-access collection of small to medium sized unit cell crystal structures [4, 3]. Over 11 years of development, COD has accumulated over... more
Crystallography Open Database (COD, http://www.crystallography.net) is the largest to date curated open-access collection of small to medium sized unit cell crystal structures [4, 3]. Over 11 years of development, COD has accumulated over 1/4 million structures. COD has an automated data submission Web site, performs routine automatic quality checks on all incoming structures and is now recommended as a database for crystallographic deposition by several scientific journals. To facilitate automatic use and discoverability of COD data, and to increase usefulness of our database for chemists, two steps were undertaken. COD was supplemented with software and data from the CrystalEye data aggregator [2]. The new software permits extracting chemical data and presenting them as structural formula, unique moieties and chemically significant fragments. We have also implemented search of crystal structures by the structural chemical formulae of the target compounds. To facilitate data curati...
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In this study, the results of different analyses carried out on thirteen samples of figulina pottery are presented. These samples are from four Italian Neolithic sites and are dated to the end of the 6th --beginning of the 5th millennium... more
In this study, the results of different analyses carried out on thirteen samples of figulina pottery are presented. These samples are from four Italian Neolithic sites and are dated to the end of the 6th --beginning of the 5th millennium BC cal. On the basis of the results obtained from scanning electron microscopy, energy dispersive X ray spectroscopy, porosimetry, density measurements and X ray diffractometry, specific features of this ceramics have been inferred. These features can be as preliminary, even in view of the limited number of the analysed specimens, indicators to tell locally produced from imported products. Moreover, interesting data on porosity and related microstructure and phase composition emerged from the experimental results. In particular, an elevated concentration of glassy phase has been found in all samples, although in the prehistoric sites no indications or remains of any advanced pyrotechnological facility were found. The estimated firing temperatures in...
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The synthesis of strontium ferrite SrFeO3-delta has been explored through wet-chemistry methods in order to optimize a quick, easy and reproducible method to obtain the perovskite in pure crystalline form with a high yield. Among the... more
The synthesis of strontium ferrite SrFeO3-delta has been explored through wet-chemistry methods in order to optimize a quick, easy and reproducible method to obtain the perovskite in pure crystalline form with a high yield. Among the three investigated synthetic paths, (i) coprecipitation of hydroxides, (ii) coprecipitation of oxalates and (iii) polyol-assisted coprecipitation, only the second one was effective in obtaining the desired perovskite modification as a single phase. The products were analyzed by means of powder X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), to determine the crystalline structure and the chemical composition of the sample surface, respectively, and to optimise the synthetic process. Pure samples were further characterised by means of inductively coupled plasma (ICP-AES) analysis, nitrogen adsorption, elemental analysis, temperature programmed reduction (TPR) and Mssbauer spectroscopy.
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The full quantitative characterization of nanopowders using transmission electron microscopy scattering patterns is shown. This study demonstrates the feasibility of the application of so-called combined analysis, a global approach for... more
The full quantitative characterization of nanopowders using transmission electron microscopy scattering patterns is shown. This study demonstrates the feasibility of the application of so-called combined analysis, a global approach for phase identification, structure refinement, characterization of anisotropic crystallite sizes and shapes, texture analysis and texture variations with the probed scale, using electron diffraction patterns of TiO2 and Mn3O4 nanocrystal aggregates and platinum films. Electron diffraction pattern misalignments, positioning, and slight changes from pattern to pattern are directly integrated and refined within this approach. The use of a newly developed full-pattern search-match methodology for phase identification of nanopowders and the incorporation of the two-wave dynamical correction for diffraction patterns are also reported and proved to be efficient.
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