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MARIA CANNIO
COLLABORATORE DI RICERCA Dipartimento di Ingegneria "Enzo Ferrari"
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Pubblicazioni
2023
- Experimental assessment and predictive model of the performance of Ti-based nanofluids
[Articolo su rivista]
D'Adamo, Alessandro; Diana, Martino; Corda, Giuseppe; Cucurachi, Antonio; Cannio, Maria; Pellacani, Andrea; Romagnoli, Marcello; Stalio, Enrico; Santangelo, Paolo Emilio
abstract
The need for innovative propulsion technologies (e.g., fuel cells) in the mobility sector is posing a higher-than-ever burden on thermal management. When low operative temperature shall be ensured, dissipation of a significant amount of heat is requested, together with limited temperature variation of the coolant; mobile applications also yield limitations in terms of space available for cooling subsystems. Nanofluids have recently become one of the most promising solutions to replace conventional coolants. However, the prediction of their effectiveness in terms of heat-transfer enhancement and required pumping power still appears a challenge, being limited by the lack of a general methodology that assesses them simultaneously in various flow regimes. To this end, an experiment was developed to compare a conventional coolant (ethylene glycol/water) and a TiO2-based nanofluid (1% particle loading), focusing on heat transfer and pressure loss. The experimental dataset was used as an input for a physical model based on two independent figures of merit, aiming at an a priori evaluation of the potential simultaneous gain in heat transfer and parasitic power. The model showed conditions of combined gain specifically for the laminar flow regime, whereas turbulent flows proved inherently associated to higher pumping power; overall, criteria are presented to evaluate nanofluid performance as compared to that of conventional coolants. The model is generally applicable to the design of cooling systems and emphasizes laminar flow regime as promising in conjunction with the use of nanofluids, proposing indices for a quantitative a priori evaluation and leading to an advancement with respect to an a posteriori assessment of their performance.
2022
- Insight into t->m transition of MW treated 3Y-PSZ ceramics by grazing incidence X-ray diffraction
[Articolo su rivista]
Riva, V.; Boccaccini, D.; Cannio, M.; Maioli, M.; Valle, M.; Romagnoli, M.; Mortalo, C.; Leonelli, C.
abstract
The influence of a microwave hybrid heat treatment (MHH) on the surface and in-depth mineralogical transformation of pre-sintered 3Y-PSZ was investigated. 3Y-PSZ samples were prepared by slip casting and sintered by conventional firing (1270 °C). Then, different MHH treatments from 5 to 15 min. at 1200 °C were applied to obtain a fully stabilized 3Y-TZP. The monoclinic fraction depth profiles in the first micrometres (up to 5) of thickness were investigated by means of the grazing incident X-ray diffraction technique (GIXRD). A good sintering degree with practically nil closed porosity and grain growth was achieved after MHH of 15 min. MHH increases the tetragonal phase content both in the surface and in-depth, reducing completely the monoclinic phase shell typically found after conventional sintering. A new parabolic model is proposed for the convoluted monoclinic fraction depth profile, which through the value of its horizontal asymptote allows the determination of the monoclinic shell thickness.
2022
- Surface Optimization of Commercial Porous Ti Substrates by EPD of Titanium Nitride
[Articolo su rivista]
Mortalò, Cecilia; Cannio, Maria; Zin, Valentina; Miorin, Enrico; Montagner, Francesco; Pasquali, Luca; Montecchi, Monica; Boccaccini, Dino Norberto; Fabrizio, Monica; Deambrosis, Silvia Maria
abstract
In this work, the infiltration of TiN powders by electrophoretic deposition (EPD) in aqueous media was considered as alternative method to reduce the size craters and the roughness of commercial porous Ti substrates. Ti substrates can be used as suitable supports for the deposition of dense hydrogen separation TiNx-based membranes by physical vapor deposition (PVD) techniques. The influence of various EPD deposition parameters on surface morphology and roughness of TiN-infiltrated substrates were investigated in order to optimize their surface properties. The results suggest that a multi-step EPD procedure is an effective technique for reducing substrate surface defects of commercial porous Ti substrates which could then be successfully used as proper supports for the deposition of dense and defect-free TiNx layers, also aligning the thermal mismatch between the active layer and the porous substrate.
2021
- Bioactive glass applications: A literature review of human clinical trials
[Articolo su rivista]
Cannio, M.; Bellucci, D.; Roether, J. A.; Boccaccini, D. N.; Cannillo, V.
abstract
The use of bioactive glasses in dentistry, reconstructive surgery, and in the treatment of infections can be considered broadly beneficial based on the emerging literature about the potential bioactivity and biocompatibility of these materials, particularly with reference to Bioglass® 45S5, BonAlive® and 19-93B3 bioactive glasses. Several investigations have been performed (i) to obtain bioactive glasses in different forms, such as bulk materials, powders, composites, and porous scaffolds and (ii) to investigate their possible applications in the biomedical field. Although in vivo studies in animals provide us with an initial insight into the biological performance of these systems and represent an unavoidable phase to be performed before clinical trials, only clinical studies can demonstrate the behavior of these materials in the complex physiological human environment. This paper aims to carefully review the main published investigations dealing with clinical trials in order to better understand the performance of bioactive glasses, evaluate challenges, and provide an es-sential source of information for the tailoring of their design in future applications. Finally, the paper highlights the need for further research and for specific studies intended to assess the effect of some specific dissolution products from bioactive glasses, focusing on their osteogenic and angio-genic potential.
2021
- Electrophoretic deposition: An effective technique to obtain functionalized nanocoatings
[Capitolo/Saggio]
Cannio, M.; Boccaccini, D. N.; Ponzoni, C.; Leonelli, C.
abstract
Nowadays, perovskite-structured (e.g., ferrite, cobaltite, and manganite) and other oxide (e.g., titania, zirconia, and yttria) coatings are of great interest in industrial applications such microelectronics, metal corrosion protection, photocatalytic degradation of organic pollutants, and electrochemical energy conversion devices. Different techniques, like pulsed laser deposition, magnetron sputtering, combustion chemical vapor deposition, chemical vapor deposition, are currently used to prepare homogeneous, thin and dense nanofilms. This work aims at exploring the electrophoretic deposition as an effective technique able to obtain functionalized nanocoatings due to its advantages with respect to the aforementioned deposition techniques. Electrophoretic deposition main advantages include simplicity of the method, high versatility, the possibility to control the structure, film thickness size scalability (from few nm up to tens of microns) and the possibility to form multilayer films with low-cost equipment at high deposition rates. In addition, to deposition time, suspension concentration, electrode distance, and applied voltage are crucial to tailor the layer thickness and uniformity.
2021
- Smart catalyst deposition by 3D printing for Polymer Electrolyte Membrane Fuel Cell manufacturing
[Articolo su rivista]
Cannio, Maria; Righi, Stefania; Santangelo, Paolo Emilio; Romagnoli, Marcello; Pedicini, Rolando; Carbone, Alessandra; Gatto, Irene
abstract
Polymer Electrolyte Membrane Fuel Cells (PEMFC) are arguably the most employed fuel-cell types in various industry sectors, as they operate at low temperature and exhibit short start-up time and high durability. PEMFC manufacturing is currently transitioning from low-volume to mass production. Within this effort, efficient catalyst deposition to produce MEA (Membrane Electrode Assembly) electrodes has become instrumental, since very expensive raw materials are involved. This work focuses on an Additive Manufacturing (AM) technique e a modified 3D printing approach e used to release catalytic inks onto PEMFC electrodes. Some catalyst-free suspensions were designed to resemble a catalytic ink and characterized to assess their printability by microextrusion. Mixtures of distilled water, ethanol and graphite were prepared and tested. Granulometric and rheometric analyses were conducted to optimize the composition towards low viscosity values and short drying time. Repeatability of the released amount and its homogeneousness onto the target surface were evaluated. The most suitable ink formulation was loaded with platinum, a perfluorosulfonic ionomer, a pore former (NH4CO3) and deposited onto Gas Diffusion Layers (GDL). Scanning Electron Microscopy (SEM) measurements were performed on the 3D-printed electrodes to characterize it. Preliminary electrochemical fuel-cell tests were carried out towards a comparison with conventional electrodes: the proposed deposition technique appears able to produce electrodes that align with state-of-the-art performance level.
2020
- Manufacturing of BaCe0.65Zr0.20Y0.15O3-δ-Ce0.85Gd0.15O2-δ structures by micro-extrusion 3D-printing
[Articolo su rivista]
Cannio, M.; Mortalo, C.; Prestianni, M.; Andreola, F.; Deambrosis, S. M.; Miorin, E.; Zin, V.; Boccaccini, D. N.; Romagnoli, M.
abstract
BaCe0.65Zr0.20Y0.15O3-δ-Ce0.85Gd0.15O2-δ (BCZ20Y15-GDC15) is currently one of the most studied composites for applications as dense ceramic membranes for H2 purification and membrane reactors. However, the efficiency of the structure represents a crucial issue to be solved for its practical uses. In this work the optimization of suitable slurries for the manufacturing of green asymmetric BCZ20Y15-GDC15 structures by μ-extrusion 3D-printing was investigated. The effect of the composition and rheological behavior on the stability and printability of the slurries was evaluated. Then, optimized slurries with different solid content were printed by a home-made μ-extrusion 3D printer through a step by step process: smooth and defect-free as-printed asymmetric structures with planar architecture were obtained.
2019
- Redox-Active Ferrocene grafted on H-Terminated Si(111): Electrochemical Characterization of the Charge Transport Mechanism and Dynamics
[Articolo su rivista]
Fontanesi, C.; Como, E. D.; Vanossi, D.; Montecchi, M.; Cannio, M.; Mondal, P. C.; Giurlani, W.; Innocenti, M.; Pasquali, L.
abstract
Electroactive self-assembled monolayers (SAMs) bearing a ferrocene (Fc) redox couple were chemically assembled on H-terminated semiconducting degenerate-doped n-type Si(111) substrate. This allows to create a Si(111)|organic-spacer|Fc hybrid interface, where the ferrocene moiety is covalently immobilized on the silicon, via two alkyl molecular spacers of different length. Organic monolayer formation was probed by Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) and X-ray photoelectron spectroscopy (XPS) measurements, which were also used to estimate thickness and surface assembled monolayer (SAM) surface coverage. Atomic force microscopy (AFM) measurements allowed to ascertain surface morphology and roughness. The single electron transfer process, between the ferrocene redox probe and the Si electrode surface, was probed by cyclic voltammetry (CV) measurements. CVs recorded at different scan rates, in the 10 to 500 mV s−1 range, allowed to determine peak-to-peak separation, half-wave potential, and charge-transfer rate constant (KET). The experimental findings suggest that the electron transfer is a one electron quasi-reversible process. The present demonstration of surface engineering of functional redox-active organometallic molecule can be efficient in the field of molecular electronics, surface-base redox chemistry, opto-electronic applications.
2019
- Review of catalyst-deposition techniques for PEMFC electrodes
[Articolo su rivista]
Santangelo, Paolo Emilio; Cannio, Maria; Romagnoli, Marcello
abstract
Catalyst deposition has been a significant part of fuel-cell manufacturing since their entry into mass-production industry, especially to limit the inevitable use of critical raw materials. This review focuses on a variety of techniques that may be applied towards a controlled deposition onto PEMFC substrates. The current manufacturing process consists of depositing inks onto decal-transfer carrier films, then bound to the membrane by heat and pressure. Among the conventional methods for ink deposition, gravure printing and screen printing appear the most promising. The former consists of engraving the desired image areas into the surface of a cylinder; the ink lies ultimately within engraved cells and is transferred from those cells to the substrate. In screen printing, the ink is forced through a fine fabric screen and flows through the open meshes, according to the desired pattern. Additive layer manufacturing and inkjet printing are also considered as prominent alternatives, thanks to their higher ink-deposition control onto the substrate, mainly through the drop-on-demand approach. The need for achieving higher flexibility and quality in MEA production seems to favor inkjet printing and additive layer manufacturing, able to lead to a significantly higher catalyst-layer homogeneousness. However, they require assessment of ink rheological properties and formulation.
2019
- Smart catalyst deposition by 3D printing for low temperature fuel cells
[Abstract in Atti di Convegno]
Cannio, Maria; Santangelo, Paolo Emilio; Romagnoli, Marcello; Pedicini, Rolando; Gatto, Irene
abstract
Polymer Electrolyte Membrane Fuel Cells (PEMFC) are arguably the most robust and integrated into various industry sectors among fuel cells, as they operate at low temperature and exhibit short start-up time. Currently, PEMFC manufacturing is transitioning from low-volume to mass production. However, the major hindrance against their massive use consists of high materials costs, low power density and relatively short lifetime. Notably, the need for employing platinum as a catalyst promotes exploring more convenient and effective manufacturing routes. The present work focuses on applying a microextrusion-based 3D printing system to deposit catalyst layers onto the Membrane-Electrode Assembly (MEA). A commercial 3D printer was modified to support the MEA substrate; furthermore, a peristaltic pump was inserted to supply the microextrusion printhead with the catalyst-endowed ink, finally released by a syringe. The main objectives of this work were to provide optimized compositions of catalyst inks suitable for MEA and (Gas Diffusion Layer) GDL preparation, and to assess the effectiveness of the microextrusion-based 3D printing technique in yielding homogeneous coatings. The ink was a mixture of distilled water, ethanol and graphite. Granulometric and rheometric analyses were carried out to characterize inks in a quest for low viscosity and short drying time. Repeatability of released flow rate and ink homogeneity onto the GDL target surface were also evaluated by statistical analysis. The final assessment of the coated substrates was performed by measuring the characteristic polarization curve. The results suggest that microextrusion-based 3D printing can be considered as a promising technology for fuel-cell manufacturing.
2018
- Bioglass and bioceramic composites processed by Spark Plasma Sintering (SPS): biological evaluation Versus SBF test
[Articolo su rivista]
Bellucci, D.; Salvatori, R.; Cannio, M.; Luginina, M.; Orrù, R.; Montinaro, S.; Anesi, A.; Chiarini, L.; Cao, G.; Cannillo, V.
abstract
The biocompatibility of hydroxyapatite (HA), a lab-made bioglass (BGCaMIX) with high crystallization temperature and different HA/BGCaMIX composites, pro- duced by Spark Plasma Sintering (SPS), was tested with respect to murine osteocytes both by direct and indirect tests, in order to also investigate possible cytotoxic effects of the samples’ extracts. Previous investigations demon- strated that the samples’ bioactivity, evaluated in a simu- lated body fluid solution (SBF), increased with the increas- ing amount of BGCaMIX in the sample itself. Although none of the samples were cytotoxic, the findings of the bi- ological evaluation did not confirm those arising from the SBF assay. In particular, the results of direct tests did not show an enhanced “biological performance” of materials with higher glass content. This finding may be due to the high release of ions and particulate from the glass phase. On the contrary, the performance of the BGCaMIX alone is better for the indirect tests, based on filtered samples’ extracts. This work further demonstrates that, when con- sidering bioglasses and HA/bioglass composites, the re- sults of the SBF assays should be interpreted with great care, making sure that the results arising from direct con- tact tests are integrated with those arising from the indirect ones.
2018
- Microstructure and engineering properties of Fe2O3(FeO)-Al2O3-SiO2 based geopolymer composites
[Articolo su rivista]
Kaze, R. C.; Beleuk a Moungam, L. M.; Cannio, M.; Rosa, R.; Kamseu, E.; Melo, U. C.; Leonelli, C.
abstract
The objective of this study is to develop low cost, eco-friendly and sustainable building materials by applying the technology of mineral polymerization (geopolymerization) process on naturally abundant iron-rich aluminosilicate (laterite) materials. Iron-rich aluminosilicates based-geopolymer composites containing 10 to 40 wt% of rice husk ash (RHA) were cured at room temperature and at 90 °C. This paper examines the phase transformation, microstructural and mechanical changes that occur in the geopolymer composites when fine aggregates of quartz sand are added. Experimental results indicate good polycondensation and more cohesion resulting in high strength due to the better dissolution of RHA that provides soluble reactive silica to equilibrate the Si/Al and Si/Fe molar ratios. Ferro-sialates, Fe(Al)–S–H, were identified at the room temperature in addition to polysialates, S–A-N–H, phases. The flexural strength of resultant composites increases from 10 to 12 MPa for room temperature curing to ∼40 MPa when the composites were cured at about 90 °C as from the intensive formation of ferrisilicates. The formation of ferri-silicates that changed the flexural strength and microstructure seem to play significant role in the engineering properties of laterites based geopolymer composites making them promising candidates for applications as pavements, roads and building construction.
2018
- Review of catalyst-deposition techniques for PEMFC electrodes
[Relazione in Atti di Convegno]
Santangelo, Paolo Emilio; Cannio, Maria; Romagnoli, Marcello
abstract
Catalyst deposition has been a significant part of fuel-cell manufacturing since their entry into mass-production industry, especially to limit the inevitable use of critical raw materials. This review focuses on a variety of techniques that may be applied towards a controlled deposition onto PEMFC substrates. The current manufacturing process consists of depositing inks onto decal-transfer carrier films, then bound to the membrane by heat and pressure. Among the conventional methods for ink deposition, gravure printing and screen printing appear the most promising. The former consists of engraving the desired image areas into the surface of a cylinder; the ink lies ultimately within engraved cells and is transferred from those cells to the substrate. In screen printing, the ink is forced through a fine fabric screen and flows through the open meshes, according to the desired pattern. Additive layer manufacturing and inkjet printing are also considered as prominent alternatives, thanks to their higher ink-deposition control onto the substrate, mainly through the drop-on-demand approach. The need for achieving higher flexibility and quality in MEA production seems to favor inkjet printing and additive layer manufacturing, able to lead to a significantly higher catalyst-layer homogeneousness. However, they require assessment of ink rheological properties and formulation.
2018
- Spin-dependent electrochemistry: Enantio-selectivity driven by chiral-induced spin selectivity effect
[Articolo su rivista]
Gazzotti, Mirko; Arnaboldi, Serena; Grecchi, Sara; Giovanardi, Roberto; Cannio, Maria; Pasquali, Luca; Giacomino, Agnese; Abollino, Ornella; Fontanesi, Claudio
abstract
Spin-Dependent Electrochemistry (SDE) is a new paradigm in electrochemistry where the electrochemical response of a chiral electrode|solution interface is studied as a function of spin-polarized current. In this work, the SDE concept is further developed exploring the use of the “chiral imprinting” concept, which is implemented in two different, complementary, ways i) a chiral compound in bulk solution to obtain chiral-induced spin selectivity effect at the ferromagnetic (FM) electrode surface ii) conversely, a chiral-ferromagnetic (CFM) hybrid working electrode is produced: nickel is electrochemically co-deposited with a chiral compound, L-ta or D-(−)-tartaric acid, which is added to the electrodeposition bath; this allows to obtain a chiral co-deposited nickel-tartaric acid (Ni-LTA or Ni-DTA) working electrode. As a further innovation, the ferromagnetic working electrode is prepared by direct Ni electrodeposition on the north, or south, pole of a permanent magnet. The electrochemical response of these two chiral imprinted systems is studied by comparing cyclic voltammetry (CV) curves. The latter are recorded in the potential range relevant to the Ni(III)/Ni(II) electrochemical equilibrium, and also in the presence of glucose in bulk solution. An impressive variation in peak potentials is found when comparing CVs recorded on the north, versus south, pole of the magnet (in particular, when the co-deposited CFM working electrode is used). These results are properly rationalized within the Chiral-Induced Spin Selectivity (CISS) effect.
2017
- Substitution of sodium silicate with rice husk ash-NaOH solution in metakaolin based geopolymer cement concerning reduction in global warming
[Articolo su rivista]
Kamseu, Elie; Beleuk à. Moungam, L. M.; Cannio, Maria; Billong, Ndigui; Chaysuwan, Duangrudee; Melo, U. Chinje; Leonelli, Cristina
abstract
Rice husk ash (RHA), a by-product from the rice industry, was used as principal source of amorphous silica for the production of sodium silicate solution (MR ∼ 3) used for the replacement of standard commercial sodium silicate in the mix-design of metakaolin based geopolymer composites. Three initial concentrations of NaOH were considered (8, 10 and 12 M) with the aim to investigate on the optimum dissolution and formation of silica oligomers capable to act as binder during the geopolymerization. Results (FT-IR and XRD) showed that RHA-NaOH sodium silicate solutions have characteristics similar to that of standard commercial sodium silicate and the residual carbonates present in the viscous pastes can be monitored during the preparation of geopolymers using the mix-design. Combined 25 vol% standard sodium silicate solution with ∼75 vol% of RHA-NaOH based sodium silicate solution conducted to good polycondensation, densification, high flexural strength (∼8 MPa) and low porosity similar to that of the standard matrix of metakaolin based composites. The new approach is found promising for the significant reduction of the Global Warming Potential of Geopolymers.
2016
- Preparation of an aqueous graphitic ink for thermal drop-on-demand inkjet printing
[Articolo su rivista]
Romagnoli, Marcello; Gualtieri, Eva Magdalena; Cannio, Maria; Barbieri, Francesco; Giovanardi, Roberto
abstract
A graphitic ink for thermal DOD inkjet printing was developed. Challenges to be met were related to the small size of the getting nozzle (20 μm), demanding high dispersion stability of submicron particles, as well as to the physical requirements of the printer. In addition, solvents potentially hazardous to human health were excluded a priori. These necessities led to the development of a ternary aqueous solvent system based on 2-propanol and monoethylene glycol, offering an environmental-friendly alternative to conventional graphene solvents. In addition, high flexibility in terms of physical properties (e.g. surface tension, viscosity, density) important for jetting is obtained. Size reduction and exfoliation, accomplished by wet-grinding of graphite in the presence of a surfactant, were followed by laser diffraction and XRD line broadening analyses, respectively. The separated graphitic colloids used for preparation of inks were composed of ca 30 layers of AB–stacked graphene flakes, as determined by line broadening analyses (XRD data). Jetting of an ink with a solid content of 0.3 mg/mL gave a thickness increase of ca. 25 nm/pass, as determined by FESEM. Electrical characterization evidenced the need to remove residual organic molecules to regain the electrical properties of the graphitic particles.
2016
- Stabilization and thermal conductivity of aqueous magnetite nanofluid from continuous flows hydrothermal microwave synthesis
[Articolo su rivista]
Cannio, Maria; Ponzoni, Chiara; Gualtieri, Magdalena Lassinantti; Lugli, Eleonora; Leonelli, Cristina; Romagnoli, Marcello
abstract
Magnetite, Fe3O4, nanoparticles, synthesized by hydrothermal microwave assisted technique in continuous flow, are characterized by X-ray diffraction, FTIR and TEM. The suspension stabilization of the nanoparticles dispersed in aqueous media is evaluated by the zeta potential trend and particle size distribution. The effect of the pH, the addition of a phosphate based dispersant and the sonication time on the suspension stabilization are investigated in detail. Moreover, once identified the most stable nanofluid, its thermal properties are measured to evaluate its possible application as heat transfer fluid. The preliminary results indicate a significant enhancement of magnetite water based nanofluid thermal conductivity with respect to water (up to 25%) and conventional water based fluid.
2015
- Geopolymers: An option for the valorization of incinerator bottom ash derived “end of waste”
[Articolo su rivista]
Lancellotti, Isabella; Cannio, Maria; Bollino, Flavia; Catauro, Michelina; Barbieri, Luisa; Leonelli, Cristina
abstract
In the present paper, bottom ashes from urban waste incineration wer used as sole source material to develop geopolymers activated with alkali solution. This study intends to gather basic structural data on the synthesized materials at fixed curing times (3 h;1, 4, 5, 7, 30 days; 20 months) by X-ray (XRD) and Fourier Transform Infrared (FTIR) analysis. Curing time affects both crystalline phase transformation and the geopolymeric gel structure. The XRD results showed the starting of geopolymerization, due to the alkali activation, already within the first 3 hof curing. New phases such as hydrated sodium carbonate and gismondine, confirming the progressive ash reactivity, appeared after 4 h and 1 day of curing respectively. Finally, after approximately 30 days curing at room temperature, the condensation process and, consequently, the formation of a stable 3D gel of aluminosilicate network occurred. FTIR showed a 40 cm_1 displacement of the band at 980cm_1 during the first hours of the geopolymer formation confirming the formation of the geopolymeric network also from a matrix without metakaolin. Furthermore Scanning Electron Microscopy (SEM–EDS) analyses were performed to assess morphological characteristics and to evaluate the presence of unreacted aluminosilicate particles in the obtained geopolymers.
2015
- Stabilization of bismuth ferrite suspensions in aqueous medium with sodium polyacrylate characterized by different molecular weights
[Articolo su rivista]
Ponzoni, Chiara; Cannio, Maria; Rosa, Roberto; Leonelli, Cristina
abstract
Electrostatic stabilization of bismuth ferrite BiFeO3 (BFO) single phase micronized particles suspended for the first time in aqueous medium, using sodium polyacrylate (Na-PAA) as suspending agent, was investigated to form homogeneous films through electrophoretic deposition technique. The dispersion efficiency was evaluated in terms of the zeta potential trend as a function of pH and sediment percentage, employing a fast and easy spectrophotometric method. All the tests were performed using three suspending agents characterized by the same polyacrylate functional group (-COONa) but with different molecular weights (Na-PAA Mw = 2100, 5100, and 20 000). The effect of BFO particles concentration (wt%), suspending agent concentration (wt%), suspending agent molecular weight and sonication time have been evaluated. The results showed that for all the experiments carried out the electrostatic stabilization of the BFO micronized particles in aqueous medium is accomplished in high basic pH range (8.5-9 or 9-11) depending on the molecular weight of the polyacrylate additive.
2015
- Ultrafast microwave hydrothermal synthesis and characterization of Bi1-xLaxFeO3 micronized particles
[Articolo su rivista]
Ponzoni, Chiara; Cannio, Maria; Boccaccini, D. N.; Bahl, C. R. H.; Agersted, K.; Leonelli, Cristina
abstract
In this work a microwave assisted hydrothermal method is applied to successfully synthesize lanthanum doped bismuth ferrites (BLFO, Bi1-xLaxFeO3 where x = 0, 0.15, 0.30 and 0.45). The growth mechanism of the Bi1-xLaxFeO3 crystallites is discussed in detail. The existence of the single-phase perovskite structure for all the doped samples is confirmed by the X-ray powder diffraction patterns. A peak shift, observed at lower angle with increasing La doping concentration, indicates that the BiFeO3 lattice is doped. The results of TG/DTA show a shift in the transition temperature from 805 °C to 815 °C as function of the La-doping for all the doped powders. At higher levels of La doping, i.e. x = 0.30 and 0.45, significant weight losses occur above 860 °C suggesting a change in the physical and chemical properties. Finally, magnetic measurements are carried out at room temperature for pure BiFeO3 and Bi0.85La0.15FeO3. The results indicate that the materials are both weakly ferromagnetic, with no significant hysteresis in the curves.
2014
- An efficent and fast analytical procedure for the bromine determination in waste electrical and electronic equipment plastics
[Articolo su rivista]
Taurino, Rosa; Cannio, Maria; Manfredini, Tiziano; Pozzi, Paolo
abstract
n this study, X-ray fluorescence (XRF) spectroscopy was used, in combination with micro-Raman spectroscopy, for a fast determination of bromine concentration and then of brominated flame retardants (BFRs) compounds in waste electrical and electronic equipments. Different samples from different recycling industries were characterized to evaluate the sorting performances of treatment companies. This investigation must be considered of prime research interest since the impact of BFRs on the environment and their potential risk on human health is an actual concern. Indeed, the new European Restriction of Hazardous Substances Directive (RoHS 2011/65/EU) demands that plastics with BFRs concentration above 0.1%, being potential health hazards, are identified and eliminated from the recycling process. Our results show the capability and the potential of Raman spectroscopy, together with XRF analysis, as effective tools for the rapid detection of BFRs in plastic materials. In particular, the use of these two techniques in combination can be considered as a promising method suitable for quality control applications in the recycling industry.
2014
- Metakaolin-based inorganic polymer composite: Effects of fine aggregate composition and structure on porosity evolution, microstructure and mechanical properties
[Articolo su rivista]
Kamseu, E.; Cannio, M.; Obonyo, E. A.; Tobias, F.; Bignozzi, M. C.; Sglavo, V. M.; Leonelli, C.
abstract
This paper examines the phase transformation, pore evolution, microstructural and mechanical changes that occur in inorganic polymer cement (IPC) in the presence of three different grade of fine aggregates (φ < 100 μm) of ladle slag, nepheline syenite and quartz sand. Experimental results indicate that polycondensation was enhanced in nepheline syenite based specimens, compared to quartz sand, due to the increase in HMAS phases in relation to the dissolution and interaction of amorphous/disordered fraction of aggregates. HCS and HCAS with HMAS phases were identified in the ladle slag based specimens. The formation of these new phases reduced both the cumulative pore volume and pores size. The apparent increase in volume of capillary pores in ladle slag based specimens was explained by the residual bubbles from the carbonates included in raw slag. The flexural strength of the inorganic polymer cement increases from 4 MPa to 4.2, 4.8 and 6.8 MPa with the addition of 20 wt% of quartz sand, nepheline syenite and ladle slag respectively. These values increase significantly between 28 and 180 days of curing (9.1 MPa for ladle slag and 10.0 MPa for nepheline syenite). It was concluded that fines can be used to remove the HM and poorly bounded alumina oligomers in metakaolin based inorganic polymer matrices and improve the interfacial zone for the design of an optimum grade and high-performance composites. © 2014 Elsevier Ltd. All rights reserved.
2014
- New Methods for the Assessment of Thermal Shock Resistance in Refractory Materials
[Voce in Dizionario o Enciclopedia]
Cannio, Maria; Boccaccini, Dino Norberto; Romagnoli, Marcello
abstract
2013
- Effect of low-temperature high-pressure sintering on BiFeO3 density, electrical magnetic and structural properties
[Articolo su rivista]
Ponzoni, C.; Cannio, M.; Rosa, R.; Chudoba, T.; Pietrzykowka, E.; Buscaglia, V.; Finocchio, E.; Nanni, P.; Lojkowski, W.; Leonelli, C.
abstract
Single-phase multiferroic BiFeO3 (BFO) powders were prepared by hydrothermal microwave synthesis and dense BiFeO3 ceramics were fabricated for the first time by the low-temperature high-pressure (LTHP) sintering technique. Effect of sintering temperature ranging from 400 to 800 °C (3 min and 10 min) and pressure of 3-8 GPa on structural, microstructural, electric and magnetic properties were investigated through X-ray diffraction, scanning electron microscope (SEM), electrochemical impedance spectroscopy (EIS), density and magnetic measurements. The results highlighted that LTHP sintering method, thanks to the high pressure involved, requires lower temperature and shorter time than other techniques, avoiding BiFeO3 phase degradation. SEM images show that for short experimental time (t = 3 min) the average grain size of the sintered samples was approximately the same size of raw powder. Extending the sintering time up to 10 min the grain growth phenomena occurred. Moreover the results indicate that the best obtained density value was around 98% of theoretical density. The dielectric behavior of BiFeO3 ceramics was not significantly influenced by the LTHP sintering conditions. Magnetic measurements showed that ceramic BiFeO 3 is weakly ferromagnetic at room temperature. © 2013 Taylor & Francis.
2013
- Electrophoretic deposition of multiferroic BiFeO3 sub-micrometric particles from stabilized suspensions
[Articolo su rivista]
Ponzoni, Chiara; Rosa, Roberto; Cannio, Maria; Buscaglia, Vincenzo; Finocchio, Elisabetta; Nanni, Paolo; Leonelli, Cristina
abstract
The electrophoretic deposition (EPD) was applied to BiFeO3 (BFO) powders, one of the most interesting multiferroic compounds characterized by simultaneous magnetic and ferroelectric activity, to form homogeneous films. The preparation and characterization of stable BFO colloidal suspensions in aqueous, organic and mixed solvents were investigated by zeta potential measurements at room temperature in the presence of surfactants. BFO thin films were then deposited on steel substrates from stabilized BFO suspensions, by adjusting the preparative parameters to optimize the film quality. The compositional, morphological and electrical characteristics of the obtained BFO films, together with thickness measurements, were studied using SEM, XRD, AFM, EIS and optical surface profilometer. EPD method applied to BFO stable suspensions produced homogeneous thickness BFO films, free from pinholes and cracks, that were successively sintered and characterized also in terms of photocatalytic response.
2013
- Optimization of BFO microwave-hydrothermal synthesis: Influence of process parameters
[Articolo su rivista]
Ponzoni, Chiara; Rosa, Roberto; Cannio, Maria; Buscaglia, Vincenzo; Finocchio, Elisabetta; Nanni, Paolo; Leonelli, Cristina
abstract
Multiferroic materials exhibiting ferromagnetic and ferroelectric properties in a certain temperature range are acquiring interest in information storage and sensors applications. Facile microwave hydrothermal synthesis route was optimized for the preparation of BiFeO3 (BFO) pure-phase. Influence of process parameters (i.e. precursor ratio, mineralizer concentration, temperature, time) on phase formation, particle size distribution and morphology was investigated in detail. The BFO powders were characterized by XRD, ESEM and TEM. Single phase BFO was formed using KOH, 8 M at 200 °C, 30 min and KOH, 10 M at 180 °C, 30 min; the presence of Na 2CO3, acting as electron donor, allowed the reaction to be performed at lower KOH concentrations and temperatures, 6 and 8 M at 180 °C in 30 min. Particles' morphology evolution with concentration and temperature without Na2CO3 followed the sequence: spherical, lamellar, lamellar semi-cubic, cubic; while with Na2CO3 addition the evolution was: lamellar semi-cubic, cubic and prismatic truncated octahedron shape. © 2012 Elsevier B.V. All rights reserved.
2012
- A lifetime prediction method based on Cumulative Flaw Length Theory
[Articolo su rivista]
Boccaccini, Dino Norberto; Maioli, Marco; Cannio, Maria; I., Dlouhy; Romagnoli, Marcello; Leonelli, Cristina; A. R., Boccaccini
abstract
Ultrasonic pulse velocity testing (UPVT) was carried out to perform non-destructive quality control of refractory plates. Used in conjunction with fracture mechanics, ultrasonic velocity measurements have proved a powerful technique for detecting, positioning and sizing internal voids and cracks in the samples, originated from the manufacturing process. Two cordierite-mullite refractory compositions exhibiting different microstructure and crack propagation behaviour were characterized through their lifetime during which they were subjected to thermal shock loading. In this paper, a new statistical method is proposed which allows to estimate the lifetime when the stress state that will be applied in service (loading) and the scattering of the ultrasonic velocity data in the as-received state are known. Since this lifetime prediction method is based on a non-destructive technique, it could be implemented into a code in an automatic quality control device for continuous lifetime estimation. The correlation between crack propagation behaviour and thermal shock resistance is discussed and semi-empirical models were developed to predict the service life of refractory plates from the measured values of ultrasonic velocities on as-received samples.
2012
- Full quantitative phase analysis of hydrated lime using the Rietveld method
[Articolo su rivista]
Gualtieri, Eva Magdalena; Romagnoli, Marcello; Miselli, Paola; Cannio, Maria; Gualtieri, Alessandro
abstract
Full quantitative phase analysis (FQPA) using X-ray powder diffraction and Rietveld refinements is a well-established method for the characterization of various hydraulic binders such as Portland cement and hydraulic limes. In this paper, the Rietveld method is applied to hydrated lime, a non-hydraulic traditional binder. The potential presence of an amorphous phase in this material is generally ignored. Both synchrotron radiation and a conventional X-ray source were used for data collection. The applicability of the developed control file for the Rietveld refinements was investigated using samples spiked with glass. The results were cross-checked by other independent methods such as thermal and chemical analyses. The sample microstructure was observed by transmission electron microscopy. It was found that the consistency between the different methods was satisfactory, supporting the validity of FQPA for this material. For the samples studied in this work, the amount of amorphous material was in the range 2–15 wt.%.
2012
- Mechanical activation of raw materials in the synthesis of Fe2O3-ZrSiO4 inclusion pigment
[Articolo su rivista]
Cannio, Maria; Bondioli, Federica
abstract
The traditional ceramic industry has recently witnessed increasing interest in the obtainment of inclusion pigments to stabilize at firing temperature and in the action of molten glass unstable chromospheres such as hematite or cadmium sulphoselenide.This work focuses in the introduction, before the calcination step, of a high energy milling step (mechanosynthesis) to improve the inclusionefficiency of hematite into the zircon matrix by solid state reaction. In particular the synthesis of hematite–zircon inclusion pigment was optimized through an accurate control of the raw material milling time and calcination temperature. The mechanical activation modifies the conditions in which chemical reactions usually take place changing the reactivity of as-milled solids by increase of reaction rates and lowering the reaction temperatures of ground powders.
2012
- WEEE: No waste anymore but secondary raw material
[Capitolo/Saggio]
Andreola, Nora Maria; Barbieri, Luisa; Cannio, Maria; Giovanardi, Roberto; Lancellotti, Isabella; Pozzi, Paolo; Soragni, Ercole
abstract
The management of Waste Electrical and Electronic Equipment (WEEE) is a topic of great interest, now being an integral part of the Italian D.Lgs. 151/2005. In order to protract life cycle of this waste, composed by glass, polymers and metals, a great effort is done to develop separation, reclamation, recycling and recovery techniques. This study reports the results achieved on the characterization of different materials constituting TV sets and computers, low environmental impact techniques of extraction and recovery of precious metals from electronic circuitry and the use of glassy components as secondary raw material in the ceramic field instead of virgin compounds.
2010
- Chromium (VI) Galvanic Bath: Chemical Treatments and Possible Recycling Ways of the Obtained Sludges
[Capitolo/Saggio]
Cannio, Maria; Barbieri, Luisa; Bondioli, Federica
abstract
Galvanic processes, that increase corrosion resistance properties and improve wear qualities of metal materials, are based on metal plating baths and rinsewaters. They generate effluents with a metal concentration varying with the installed process. Traditional systems reduce the toxicity of wastewater by aggregating disposed aqueous solutions of various concentrations, followed by treatment with chemicals to coagulate, flocculate, and settle out solid wastes for off-site disposal. In this paper the efficiency of different precipitating agents was evaluated in order to obtain a Cr (III) sludge.There are several treatment routes proposed in the literature to avoid dumping, or in other words, recycle the wastes. Recent increase in the cost of landfill disposal and decrease in number of disposal sites have led to consideration of alternative routes and treatments. For this reason, the screening results of scientific activity conducted on a laboratory scale on the possibility to both inertize and valorize the obtained galvanic sludge in the traditional ceramic filed (glasses, bricks, tiles, pigments and glazes) were reported with particular emphasis on the possible problems and the possible ways to solve them.
2010
- The pO-Index and R Ratio Gap Methods for the Assessment of Corrosion Risk in Refractory Materials in Contact with Glass Melts
[Articolo su rivista]
Boccaccini, D. N.; Cannio, Maria; Romagnoli, Marcello; Veronesi, Paolo; Leonelli, Cristina; Boccaccini, ALDO ROBERTO
abstract
Corrosion of refractories used in glass melting technology is a complex phenomenon involving chemical wear (corrosion) and physical/mechanical wear (such as erosion and abrasion) processes as well as thermal shock and spalling. Besides the complexity in the hydrodynamics of a molten silicate bath with which refractory materials are in contact, refractories are polycrystalline heterogeneous materials containing a relatively high porosity. Pores are centers for accelerated corrosion, spalling, and penetration by the hot liquid. In this work, a corrosion study of aluminosilicate refractory crucibles by chromium and calcium oxides during the melting of Cr-containing soda lime glasses as a function of temperature (1400°–1500°C) and glass basicity has been performed. The features and mechanism of the corrosion process were compared and analyzed as a function of glass acidobasicity (pO-index) and of the ratio of network-dwelling cations to A13+ cations (R). The advantage of the pO-index and ΔR gap methods to assess refractory corrosion risk as a function of the acidobasicity differential between the refractory glassy phase and the glass melt was demonstrated. The change of the concentrations of glass constituents was monitored by ICP analysis of glass samples and correlated to the observed extent of corrosion. The crystalline composition and microstructure of the refractory materials before and after being corroded were studied by XRD analyses and SEM. Cr-doped corundum was found to be the main crystalline phase in the refractory microstructure and other mixed phases with chromium and aluminum and/or silica, which formed at the boundary layer (interface) between the glasses and the aluminosilicate refractory, were identified. The results provide a useful guide to the selection of refractory materials for application in glass and glass–ceramic manufacture in terms of their corrosion risk.
2009
- A statistical approach for the assessment of reliability in ceramic materials from ultrasonic velocity measurement: Cumulative Flaw Length Theory
[Articolo su rivista]
Boccaccini, Dino Norberto; Maioli, Marco; Cannio, Maria; Romagnoli, Marcello; Veronesi, Paolo; Leonelli, Cristina; A. R., Boccaccini
abstract
A primary objective of statistical fracture approach is to predict the probability of failure of a component for an arbitrary stress state when the failure statistics are known. This study introduces the fundamentals and application of a new approach to characterize the mechanical behaviour of high temperature ceramic materials, including refractory materials, by coupling non-destructive methods, in particular ultrasonic velocity measurement, and the Batdorf statistical fracture theory. A new approach, termed Cumulative Flaw Length Theory (CFLT), has been developed for the case of macroscopically homogeneous isotropic materials containing randomly oriented microcracks uniformly distributed in a location subjected to non-uniform multiaxial stresses. A function representing the number of cracks per unit volume is estimated based on the histograms of ultrasonic velocity measurements. This function is used without additional assumptions to determine the probability of fracture under an arbitrary stress condition. Two different cordierite-mullite high temperature ceramic materials were characterized under the assumptions of this theory to provide experimental evidence to support the model.
2009
- Application of a neural network approach to the electrophoretic deposition of PEEK–alumina composite coatings
[Articolo su rivista]
I., Corni; Cannio, Maria; Romagnoli, Marcello; A. R., Boccaccini
abstract
Nano-size Al2O3–polyetheretherketone(PEEK) composite thick films have been prepared on stainless steel substrates from non-aqueous colloidal suspensions by electrophoretic deposition (EPD). The effects on the deposition efficiency of process parameters, such as the deposition time, the difference of potential applied and their interactions were studied using a neural network approach to develop a quantitative understanding of the system. Furthermore the use of the neural network was optimized in the number of epochs, hidden layers and artificial neurons in each hidden layer by a design of experiment (DOE) analysis, demonstrating that these two methods can work together improving the final results of the neural network approach. Afterwards, a MonteCarlo analysis based on a simulation of 100,000 virtual depositions has permitted to deeply investigate the effect of independent variables (e.g. deposition time and difference of potential applied) on the deposition yield (dependent variable).
2009
- Microwave-assisted consolidation of coatings obtained by electrophoretic deposition (EPD)
[Abstract in Atti di Convegno]
Veronesi, P.; Leonelli, C.; Corradi, A. B.; Poli, G.; Romagnoli, M.; Giovanardi, R.; Rosa, R.; Cannio, M.; Michelazzi, M.; Rizzuti, A.; Boccaccini, A. R.
abstract
Electrophoretic deposition (EPD) is an electrochemical method attracting increasing interest as a material processing technique. In the first step of EPD an electric field is applied between two electrodes and charged particles suspended in a suitable liquid move toward the oppositely charged electrode; in the second step the particles accumulate at the deposition electrode and create a relatively compact and homogeneous film, which, however, requires a further consolidation step in order to fully develop satisfactory mechanical properties. In the present work, EPD conditions have been varied in order to control the initial porosity of the deposits of nano- and sub-micrometric zirconia powders, applying an innovative "zerointegral" approach. Microwave heating was then applied to rapidly sinter the deposited powders, trying to minimize grain growth. EPD and microwave heating allow to influence the final product properties and thus its end use like thermal barrier coating or for tribological applications.
2009
- Misure di conducibilità termica di materiali refrattari mediante un apparato a piastra calda con anello di guardia
[Articolo su rivista]
Boccaccini, Dino Norberto; Cannio, Maria; Veronesi, Paolo; Leonelli, Cristina; Muscio, Alberto
abstract
La conoscenza della conducibilità termica di prodotti ceramici sta assumendo importanza fondamentale per l’ottimizzazione dell’isolamento termico degli edifici in relazione alle problematiche connesse al risparmio energetico. Oggi esistono tecniche veloci, precise ed efficaci per la stima della conducibilità di materiali edilizi. Tuttavia per ottenere misure accurate di tale proprietà è opportuno scegliere il metodo di misura corretto in funzione dell’intervallo di conducibilità termica del materiale e della sua geometria. Nella realizzazione di un apparato a piastra calda con anello di guardia, nato dalla collaborazione tra DIMeC e DIMA, è stata seguita la norma ASTM C177-97. In particolare in questo lavoro viene mostrata la relazione tra conducibilità termica, densità e temperature di utilizzo di materiali refrattari
cordierite-mullite.
2008
- Assessment of viscoelastic crack bridging toughening in refractory materials
[Articolo su rivista]
Boccaccini, Dino Norberto; Cannio, Maria; T. D., Volkov Husoviæ; I., Dlouhy; Romagnoli, Marcello; Veronesi, Paolo; Leonelli, Cristina
abstract
Viscoelastic bridges can be formed in refractory ceramics while cooling from high temperatures. Such bridges can shield crack tips, thus reducingthe effective crack tip stress intensity factors leading to higher resistance to creep and thermal shock. The extent to which the crack tip stress intensityis reduced can be estimated from fracture mechanics models that include experimental measurement of crack bridging and microstructuralparameters. In this paper a novel approach is proposed for the assessment of the effective crack bridging toughening from combining destructiveand non-destructive test methods. Fracture toughness values were determined applying chevron notched specimen technique and surface damage ofthe specimen was monitored by image analysis. Different cordierite–mullite compositions characterized by different microstructure morphologiesand crack propagation behaviour were investigated. A brief discussion about the correlation between thermo-mechanical properties, microstructure,crack propagation behaviour and thermal shock resistance is presented. Moreover, an empirical model able to determine the presence andeffectiveness of the viscoelastic crack bridging ligaments acting in the microstructure under thermal shock conditions and their degradation withincreasing thermal shock cycles from parameters measured at room temperature is presented.
2008
- CHROMIUM ELECTRODEPOSITION FROM Cr(VI) LOW CONCENTRATION SOLUTIONS.
[Articolo su rivista]
Fontanesi, Claudio; Giovanardi, Roberto; Cannio, Maria; E., Soragni
abstract
This work presents a study of a hard chromiumplating process using low concentration H2CrO4 baths. Inparticular, the effect of different values of CrO3/H2SO4 ratioon coating properties such as adhesion, hardness, surfaceroughness, apparent density and microstructure were considered.To increase the solution conductivity, avoiding longdeposition times and low throwing power typical of dilutesolutions, the behaviour of various inorganic compoundswas investigated. Specifically, the compounds suitable forobtaining brighter coatings with lower surface roughnessvalues than those obtained using Fink’s solutions wereNa2SO4 and Al2(SO4)3 9 18H2O. A bath composition wasidentified, with a limited use of Cr(VI) in a solution able toproduce coatings with a better surface roughness than thoseof conventional industrial baths.
2008
- Prediction of service life of cordierite-mullite refractory materials by non-destructive methods
[Relazione in Atti di Convegno]
Boccaccini, Dino Norberto; Kamseu, Elie; Volkov Husoviæ, T. D.; Cannio, Maria; Romagnoli, Marcello; Veronesi, Paolo; Dlouhy, I.; Boccaccini, A. R.; Leonelli, Cristina
abstract
Ultrasonic pulse velocity testing was used to perform non-destructive quality control of refractory plates used as substrates in fast firing of porcelain whitewares. The measurement of the ultrasonic velocity was used to asses the presence of internal voids or cracks originated from the manufacturing procedure. Image analysis was used to predict thermal stability of the refractory materials. Two cordierite-mullite compositions were investigated that are characterized by different microstructure morphologies and crack propagation behaviour. A brief discussion about the correlation between microstructure, crack propagation behaviour and thermal shock resistance is presented. Moreover, empirical models were developed to predict the service life of refractory plates from measured values of ultrasonic velocities in plates in the as-received state.
2008
- Synthesis of chromium containing pigments from chromium galvanic sludges
[Articolo su rivista]
Andreola, Nora Maria; Barbieri, Luisa; F., Bondioli; Cannio, Maria; Ferrari, Anna Maria; Lancellotti, Isabella
abstract
In this work the screening results of the scientific activity conducted on laboratory scale to valorise chromium (III) contained in the galvanic sludge as chromium precursor for ceramic pigments are reported. The valorisation of this waste as a secondary raw material (SRM) is obtained by achievement of thermal and chemical stable crystal structures able to colour ceramic material. Two different pigments pink CaCr0.04Sn0.97SiO5 and green Ca3Cr2(SiO4)3 were synthesized by solid-state reactions using dried Cr sludge as chromium oxide precursor. The obtained pigments were characterized by X-ray diffraction and SEM analysis. Furhermore the color developed in a suitable ceramic glaze was investigated in comparison with the color developed by the pigments prepared from pure Cr2O3. The characterization carried out corroborates the thermal and chemical stability of the synthesized pigments and, especially for the Cr-Sn pink pigment, the powders develop an intense color that is very similar to the color developed by the pigments obtained starting from pure Cr2O3.
2007
- LEGISLATIVE, TECHNOLOGICAL, ADMINISTRATIVE, ECONOMICAL AND ORGANIZATIONAL ASPECTS OF THE EXECUTIVE RAEE AND ROHS
[Relazione in Atti di Convegno]
Barbieri, Luisa; Cannio, Maria; Cassanelli, Giulia; Colombo, Paolo; Pozzi, Paolo; Rabitti, Daniela; Rimini, Bianca; Rovati, Luigi
abstract
-The Italian Decree D. Lgs. n. 151/2005 and subsequent changes and supplements in agreement with Directives WEEE 2002/96/CE and 2003/108/CE “for the recovery and recycling of waste from electric and electronic equipments” and Directive RoHS 2002/95/CE “on the restriction of the use of certain hazardous substances in electrical and electronic equipment” has been analysed here. In particular, the aim of this work is to introduce legal, technological, administrative outcomes about interpretation and application of the D. Lgs. 151/2005. The main legislative novelty is represented by the Extended Producer Responsibility (EPR) that it is transferred in the burden of producers and distributors which have to support economically national systems for the WEEE recovery and treatment at the end of life. The correct management of the WEEE nevertheless, parallel of new requirements, offers to the producers stimulating opportunity both in the field of Integrated Product Policy and in the optimization of the distribution/collection nets.
2007
- Quality control and thermal shock damage characterization of high-temperature ceramics by ultrasonic pulse velocity testing
[Articolo su rivista]
Boccaccini, Dino Norberto; Romagnoli, Marcello; Veronesi, Paolo; Cannio, Maria; Leonelli, Cristina; Pellacani, Gian Carlo; T. V., Husovic; A. R., Boccaccini
abstract
Ultrasonic pulse velocity testing was carried out to perform nondestructive quality control of refractory plates used as substrates in fast firing of porcelain whiteware. Two cordierite-mullite refractory compositions characterized by different microstructure morphologies and crack propagation behavior were investigated after a number of industrial thermal cycles. Ultrasonic velocity measurements were used to determine the presence of internal voids/cracks in the samples, originating from the manufacturing procedure. A brief discussion about the correlation between microstructure, crack propagation behavior, and thermal shock resistance is presented. Empirical models were developed to predict the service life of refractory plates from measured values of ultrasonic velocities on as-received samples.
2007
- UNATEORIA STATISTICA PER VALUTARE L’AFFIDABILITÀ DI MATERIALI CERAMICI BASATA SU MISURE DI VELOCITÀ ULTRASONICA: CUMULATIVE FLAW LENGTH THEORY
[Relazione in Atti di Convegno]
Boccaccini, Dino Norberto; Maioli, Marco; Cannio, Maria; Veronesi, Paolo; Romagnoli, Marcello; Leonelli, Cristina
abstract
Uno dei principali obiettivi della teoria statistica della frattura è prevedere la probabilità di rottura per uno stress arbitrario, quando è nota la statistica di rottura. E’ stata sviluppata una nuova teoria “Cumulative Flaw Lenght Theory(CFLT)” per il caso di materiali omogenei isotropici a livello macroscopico contenenti microcricche con orientazioni random distribuite uniformemente sotto stress poliassiali. La funzione rappresentante il numero di cricche per unità di volume è basata su istogrammi relativi a misure di velocità ultrasoniche. Questa funzione è usata senza ulteriori assunzioni per determinare la probabilità di rottura in condizioni arbitrarie di stress. Questa teoria può essere facilmente incorporata in un modello a elementi finiti per prevedere la probabilità di rottura di una struttura sottoposta a stress. Inoltre il confronto della teoria con programmi esistenti usati per prevedere la probabilità di rottura di materiali ceramici e che sono basati su parametri determinati mediante prove distruttive, ad es. three point bending strenght, sottolinea il vantaggio di previsionibasate su tecniche non distruttive. Questo fatto ne permette l’impiego non solo in fase di design, ma anche per il monitoraggio dell’aumento di probabilità di rottura durante la vita in servizio. Una certa varietà di fratture introdotte durante le fasi iniziali dei metodi tradizionali di processo può portare a una affidabilità non accettabile dei materiali ceramici impiegati ad alta temperatura. Le impurezze presenti nelle materie prime (polveri, leganti..) e agglomerati formati durante il processo di formatura delle polveri sono esempi di difetti che influenzano la resistenza. Tali fratture non solo limitano la resistenza dei materiali ma incrementano lo scattering dei dati portando a affidabilità bassa (basso modulo di Weibull). La Cumulative Flaw Lenght Theory permette di valutare la funzione densità delle cricche e la probabilità di rottura a partire da dati di misura di velocità a ultrasuoni in materiali ceramici. Un nuovo metodo statistico è proposto che, basato su risultati ottenuti dalla CFLT per i campioni come ricevuti permette di valutare il vita in servizio quando il materiale è sottoposto a stress. Due diversi ceramici refrattari a base di cordierite mullite sono stati caratterizzati nell’assunzione che la teoria fosse validata in campo sperimentale. I modelli empirici di vita in servizio sono stati ottenuti considerando il numero di cicli termici sostenuti/sopportati da un numero di campioni. La buona correlazione ottenuta tra le curve teoriche e le curve ottenute con dati sperimentali mette in risalto la validità del metodo proposto.
2006
- Physical-chemical characterization of a galvanic sludge and its inertization by vitrification using container glass
[Relazione in Atti di Convegno]
Andreola, F.; Barbieri, L.; Cannio, M.; Lancellotti, I.; Siligardi, C.; Soragni, E.
abstract
Several industrial processes produce large amounts of heavy metals-rich wastes, which could be considered as "trash-can raw materials". The incorporation in ceramic systems can be regarded as a key process to permanently incorporate hazardous heavy metals in stable matrixes. In particular the aim of this work is to prepare and evaluate environmental risk assessment of coloured glass and glass-ceramic with the addition of chromium(III) galvanic sludge having a high content of Cr2O3 (15.91 wt%). Trivalent chromium compounds generally have low toxicity while hexavalent chromium is recognized by the International Agency for Research on Cancer and by the US Toxicology Program as a pulmonary carcinogen. The sludge has been characterized by ICP -AES chemical analysis, powder XRD diffraction, DTA, SEM, leaching test after different thermal treatments ranging from 400°C to 1200°C. Batch compositions were prepared by mixing this sludge with glass containers. The glass container composition is rich in SiO2 (69.89 wt%), Na 2O (12.32 wt%) and CaO (11.03 wt%), while the sludge has a high amount of CaO (42.90 wt%) and Cr2O3 (15.91 wt%). The vitrification was carried out at 1450°C in an electrical melting furnace for 2 h followed by quenching in water or on graphite mould. Chromium incorporation mechanisms, vitrification processability, effect of initial Cr oxidation state, and product performance were investigated. In particular toxic characterization by leaching procedure and chemical durability studies of the glasses and glass-ceramics were used to evaluate the leaching of heavy metals (in particular of Cr). The results indicate that all the glasses obtained were inert and the heavy metals were immobilized.
2005
- Role of the solvent in the oxidative process of a Hg electrode in presence of thiopyrimidine derivatives
[Articolo su rivista]
Bakari, Souad; Borsari, Marco; Cannio, Maria; Gavioli, Giovanna; Ranieri, Antonio; S., Peressini; C., Tavagnacco
abstract
The electrochemical oxidation of a Hg electrode in the presence of thiopyrimidine derivatives has been investigated in a collection of organic solvents using voltammetric and polarographic techniques. Remarkable adsorption phenomena control the electrochemical process, which in all cases gives rise to a Hg(I) complex. The Laviron adsorption model is found to describe well the polarographic adsorption wave. Some correlations between adsorption parameters and solvent properties have also been observed and discussed.
2004
- Redox thermodynamics of cytochrome c adsorbed on mercaptoundecanol monolayer electrodes
[Articolo su rivista]
Gavioli, Giovanna; Borsari, Marco; Cannio, Maria; Ranieri, Antonio; Volponi, G.
abstract
The redox potentials E-0´ of bovine cytochrome c adsorbed on an 11-mercapto-1-undecanol/Au self-assembled monolayer electrode were studied through direct electrochemistry as a function of the temperature in non-isothermal experiments carried out in the presence of different anions and changes of the ionic strength. The thermodynamic parameters for protein reduction (DeltaH(rc)(0´) and DeltaS(rc)(0´)) re were determined for adsorbed and solution cytochrome and the differences in E-0´ discussed in terms of the enthalpic and entropic contributions. The adsorption process seems to remove the ability of perchlorate anion to bind to the protein surface, while a certain direct interaction is still retained in the case of chloride and phosphate. A moderate increase in E-0´ of adsorbed cytochrome was measured at increasing ionic strength and discussed in the light of the opposite effect observed for solution protein.
2003
- Electrochemical behavior of diphenyl disulfide and thiophenol on glassy carbon and gold electrodes in aprotic media
[Articolo su rivista]
Borsari, Marco; Cannio, Maria; Gavioli, Giovanna
abstract
The investigation of the electrochemical reduction processes of C6H5SSC6H5 and C6H5SH in CH3CN using cyclic voltammetry indicates a different behavior on GC and Au electrodes. On GC surface adsorption phenomena are absent, the electrochemical reduction process is irreversible and diffusion controlled. For both the starting molecules the same species, C6H5S-, is formed upon reduction. The Edegrees values of the reduction processes were determined by convolution method and the standard free energy of the S-S bond of C6H5SSC6H5 estimated. On Au surface instead, a self-assembled monolayer of C6H5SAuads originated after the S-S or S-H bond breaking can be observed by simply dipping the electrode in solution of C6H5SSC6H5 and C6H5SH, respectively. The properties of the SAM were investigated by electrochemical reduction of the adsorbed thiolates. On Au electrode the reduction processes involve C6H5SAuads, and give rise to desorbed C6H5S-. A neutral radical is obtained by. electrochemical oxidation of thiolate anion. It reacts rapidly with the electrode surface to give the S-Au bond again.
2003
- Electrochemistry of Protein Coated Surfaces
[Capitolo/Saggio]
Borsari, Marco; Cannio, Maria; Ranieri, Antonio; Bellei, Marzia; S., Bakari
abstract
The redox properties of ET proteins adsorbed on electrodes have been extensively investigated over the last decade. Protein can interact with the metal surface directly or through a self assembled monolayer directly linked to the electrode. Muche effort has been devoted to the comprehension of the molecular and structural factors that control E°' and the kinetics of the electron transfer process. This article provides an overview of the most significant advanced made in this field recently.
2003
- Substituent effects in the reduction behaviour of thio- and oxopyrimidines in non-aqueous solvents
[Articolo su rivista]
Borsari, Marco; Cannio, Maria; Dallari, D; Fontanesi, Claudio; Gavioli, Giovanna; Peressini, S; Tavagnacco, C.
abstract
The electrochemical reduction of a series of thio- and oxopyrimidine derivatives has been investigated in organic solvents on mercury electrodes. In all cases the electrochemical process gave a dimeric species as the major product. The overall reduction mechanism is the same for oxo and thio derivatives, and is found to be dependent only on the nature of the ring nitrogen substituent. A 'father-son reaction' is observed when hydrogen is bound to the ring nitrogen atom: the radical anion obtained from the first electron transfer draws out the nitrogen proton of a nonreduced molecule and this then dimerizes. In the presence of a protonating agent as well as for the N-substituted derivatives, the 'father-son reaction' is not observed. Theoretical calculations have been performed to gain insight into the proposed mechanisms: the LUMO energy and the vertical electron affinity show a linear correlation with the reduction potentials. Analysis of the theoretical parameters has allowed step-by-step determination of the electrochemical reduction process. The manner in which solvent properties influence electrochemical behaviour has been examined, and the role of the acceptor number (AN) has been discussed.
2001
- Chemical-Physical characterization of the Au-C6H5SSCH3 SAM through the electrochemical study of the surface
[Poster]
Borsari, Marco; Cannio, Maria; Gavioli, Giovanna; Ranieri, Antonio
abstract
The Au-C6H5SSCH3 SAM bahaviour has been studied through linear voltammetry.
2001
- Coordination Chemistry of Thio- and Oxo-Pyrimidine Derivatives
[Articolo su rivista]
Battistuzzi, Raffaele; Battistuzzi, Gianantonio; Borsari, Marco; Cannio, Maria
abstract
Coordinative behaviour of thio- and oxo-pyrimidine towards several metal ions are reviewed emphasizing the role of the tautomeric equilibrium. Typical bonding modes, including simple donation, chelation or bridging are discussed on the basis of spectroscopic and structural results.
2001
- S-containing molecules films: characterization and use in direct electrochemistry of redox proteins
[Articolo su rivista]
Borsari, Marco; Cannio, Maria; Gavioli, Giovanna; Ranieri, Antonio
abstract
The S-containing molecules show a great affinity towards metal surfaces, particularly Au, Pt, Ag and Cu. The interaction of the metal with the solution of these molecules gives rise to the formation of an adsorbed self assembled monolayer (SAM). The preparation and structural characterization of monolayers assemblies supported on gold electrode are of great interest in the studi of the interfacial phenomena and in particular the direct electrochemistry of redox proteins.
2001
- Synthesis, crystal and molecular structure, spectroscopic and electrochemical studies of trichloro-oxo(4,6-dimethypyrimidine-2(1H)-thione)(triphenylphosphine oxide) rhenium(V) complex.
[Articolo su rivista]
Battistuzzi, Gianantonio; Cannio, Maria; Saladini, Monica; Battistuzzi, Raffaele
abstract
Reaction of 4,6-dimethylpyrimidine-2(1H)-thione (Me2pymSH) with mer-[ReOCl3(Me2S)(OPPh3)] synthon in 1:1 molar ratio inrefluxing acetone, results in the replacement of the Me2S ligand to form the mer-[ReOCl3(Me2pymSH)(OPPh3)] species. X-raydiffraction shows that the structure of the title compound consists of monomeric units with a distorted octahedral coordinationaround the rhenium(V) centre which includes the axial ReO and ReOPPh3 bonds, and in which three Cl− ions and aS-monodentate neutral Me2pymSH ligand act as equatorial ligands. The compound was also characterised using electrochemicalmeasurements and UV–Vis–NIR and IR spectroscopy.
2000
- Synthesis, magnetic, spectroscopic and electrochemical studies of mixed pyrimidine-2-thiolate/triphenylphosphine rhenium(V) and rhenium(III) complexes
[Articolo su rivista]
Battistuzzi, Gianantonio; Cannio, Maria; Battistuzzi, Raffaele
abstract
Equimolar amounts of trans-[ReOX2(OEt)(PPh3)2] (XCl, Br, I) precursors and potentially bidentate N,S-donor pyrimidine-2(1H)-thione (pymSH) react in refluxing acetone to give mononuclear octahedral paramagnetic trans-[ReIIIX2(pymS)(PPh3)2](XCl, Br, I) species. Starting from a metal–ligand molar ratio of 1:3, in the presence of N(C2H5)3 as deprotonating agent inrefluxing ethanol, the same reaction proceeds stepwise, affording octahedral [ReO(pymS)3] or [ReO(pymS)3] and pentagonalbipyramidal[Re(pymS)3PPh3] complexes as a function of the reaction time. The compounds were characterized by elementalanalysis, magnetic susceptibility, UV–Vis–NIR, IR and 1H NMR spectroscopy and by cyclovoltammetric measurements.Reaction pathways and physico-chemical properties of the complexes are discussed.