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Nuovi approcci nei corsi di Matematica per l’Architettura: connettere forme e formule in geometria attraverso esperienze laboratoriali
No full textFirst-year mathematics courses in architecture aim to provide students with scientific language, increase spatial, creative, thinking together with the ability to recognize and create forms, and enable informed use of design software. However, future Italian architects often consider these courses marginal in their education (Pagano, & Tedeschini Lalli, 2005). In order to overcome this criticality, we developed an experimental 4-hour workshop following the DBR methodology (Brown ,1992; Barab & Squire, 2004). The didactic content is the parabola, familiar to first-year students, rediscovered with activities aimed at revealing the connection between geometric form and analytical description. Students fold (on paper) the envelope of a parabola, verify the reflection property, thus "discovering" the algebraic description of the curve and, finally, apply it to a problem of architectural luminosity. After the design phase, the lab was experimented with two groups of 75 first-year students from Politecnico di Torino and Università Roma Tre in a.y. 2021-22. Comparison of our field notes with comparative analysis of the responses of a final questionnaire provided us with encouraging results on conceptual learning and engagement, with an impact on mathematics beyond the specific example considered in the workshop.I corsi di matematica del primo anno in architettura mirano a fornire agli studenti il linguaggio scientifico, aumentare il pensiero spaziale, creativo, insieme alla capacità di riconoscere e creare forme e consentire un uso consapevole dei software di progettazione. Tuttavia, i futuri architetti italiani considerano spesso questi corsi marginali nella loro formazione (Pagano & Tedeschini Lalli, 2005). Per superare questa criticità, abbiamo sviluppato un’officina sperimentale di 4 ore seguendo la metodologia DBR (Brown ,1992; Barab & Squire, 2004). Il contenuto didattico è la parabola, familiare agli studenti del primo anno, riscoperta con attività volte a svelare il legame tra forma geometrica e descrizione analitica. Gli studenti piegano (su carta) l\u27inviluppo di una parabola, ne verificano la proprietà di riflessione, "scoprendo" così la descrizione algebrica della curva e, infine, la applicano ad un problema di luminosità in architettura. Dopo la fase di progettazione, il laboratorio è stato sperimentato con due gruppi di 75 studenti del primo anno del Politecnico di Torino e dell\u27Università Roma Tre nell\u27a.a. 2021-22. Il confronto delle nostre note sul campo con l\u27analisi comparativa delle risposte di un questionario finale ci ha fornito risultati incoraggianti sull\u27apprendimento concettuale e sul coinvolgimento, con un impatto sulla matematica al di là dell\u27esempio specifico considerato nell’officina
Correlation between microstructural and mechanical properties of aluminum alloy castings produced by different foundry processes
No full text
LA TRASLUCENZA NELL’INVOLUCRO ARCHITETTONICO: materiali, prestazioni e tecnologie innovative applicate alle frontiere edilizie contemporanee.
No full textSmall Scale CMB Anisotropies with Planck: Constraints on Primordial Magnetic Fields and the Impact of Foreground/Secondary Anisotropy Residuals
No full textThe main subject of the thesis is the study of small sale Cosmic Microwave Background (CMB) radiation anisotropies. In particular two topics are investigated. The first concerns the study of the impact of a stochastic background of primordial magnetic felds (PMF) on CMB anisotropies intemperature and polarization and the derivation of the constraints on PMF with CMB data; the second topic concerns the study of the impact of small scale foreground and secondary anisotropy residuals on cosmological parameters extracted with CMB data in the contest of the Planck mission. The first part of the thesis is devoted to the investigation of all the types of perturbations induced by PMF: scalar, vector and tensor. We present the cosmological perturbation evolution equations with PMF contributions and the original results we obtained for magnetized initial conditions and for the analytical Fourier spectra of the PMF energy momentum tensor relevant components. In order to investigate the impact of magnetized perturbations on CMB anisotropies, it has been developed an extension of the public Einstein-Boltzmann code CAMB, which computes the angular power spectrum for CMB anisotropies, where all the PMF contributions have been included. The results show that the dominant PMF contribution is given by vector perturbations on small angular scales where primary CMB is suppressed by the Silk damping. In order to derive the constraints on PMF with CMB data we have developed an extension of the Markov Chain Monte Carlo public code CosmoMC, this extension is connected with the modified version of CAMB and includes PMF parameters together with the standard ones. We show the constraints we obtained with current CMB data and the forecasts we made for Planck and the satellite COrE proposal. The results show that with current data of WMAP7, ACBAR, QUaD and BICEP the PMF amplitude is constrained to less than few nGauss, with Planck the constraints are improved by a factor two and with a mission like COrE it would be possible to constrain PMF amplitude to less than nGauss. In the thesis it is investigated also the non-Gaussian contribution of PMF to CMB anisotropies. In particular, a stochastic background of PMF has a fully non-Gaussian contribution to CMB anisotropies and induce a non-zero bispectrum. We have derived the CMB magnetized bispectrum generated by scalar magnetized perturbations on large angular scales and we have derived the constraints on PMF with current non-Gaussianity data, we show that these constraints are comparable to the ones derived with CMB angular power spectrum data. The second part of the thesis is devoted to the investigation of the im¬pact of foreground and secondary anisotropy residuals on small scales on the cosmological parameters with Planck data. In particular the contributions which are relevant for Planck frequencies and capabilities are: the residual point source contributions and the residual Sunyaev Zeldovcih effect. For what concerns the point source contribution we have considered both the Poissonian term for all unresolved sources and the clustering term for the infrared galaxies. In order to marginalize over the residual contributions in cosmological parameters extraction, we have developed hybrid theoretical/empirical parametrizations for each residual considered. Together with the spectral shape of the sig¬nals it is parametrized also their frequency dependence, this allowed the reductio n of the number of parameters necessary to describe the residuals to the minimum of three, one for each contribution. We have developed an extension of the CAMB+CosmoMC code which includes the marginalization over the considered residual contributions with the approach we have presented. The code is used to investigate the impact of the foreground and secondary anisotropy residuals on the cosmological parameters and in particular, the results show the importance of the marginalization in order to not introduce biases. In the thesis it is addressed also the topic of the frequency channel combination. In particular, we have developed an original empirical method to combine the frequency channels. We show the comparison between the results obtained with this technique and the ones obtained with the standard inverse noise variance weighting method.The main subject of the thesis is the study of small sale Cosmic Microwave Background (CMB) radiation anisotropies. In particular two topics are investigated. The first concerns the study of the impact of a stochastic background of primordial magnetic felds (PMF) on CMB anisotropies intemperature and polarization and the derivation of the constraints on PMF with CMB data; the second topic concerns the study of the impact of small scale foreground and secondary anisotropy residuals on cosmological parameters extracted with CMB data in the contest of the Planck mission. The first part of the thesis is devoted to the investigation of all the types of perturbations induced by PMF: scalar, vector and tensor. We present the cosmological perturbation evolution equations with PMF contributions and the original results we obtained for magnetized initial conditions and for the analytical Fourier spectra of the PMF energy momentum tensor relevant components. In order to investigate the impact of magnetized perturbations on CMB anisotropies, it has been developed an extension of the public Einstein-Boltzmann code CAMB, which computes the angular power spectrum for CMB anisotropies, where all the PMF contributions have been included. The results show that the dominant PMF contribution is given by vector perturbations on small angular scales where primary CMB is suppressed by the Silk damping. In order to derive the constraints on PMF with CMB data we have developed an extension of the Markov Chain Monte Carlo public code CosmoMC, this extension is connected with the modified version of CAMB and includes PMF parameters together with the standard ones. We show the constraints we obtained with current CMB data and the forecasts we made for Planck and the satellite COrE proposal. The results show that with current data of WMAP7, ACBAR, QUaD and BICEP the PMF amplitude is constrained to less than few nGauss, with Planck the constraints are improved by a factor two and with a mission like COrE it would be possible to constrain PMF amplitude to less than nGauss. In the thesis it is investigated also the non-Gaussian contribution of PMF to CMB anisotropies. In particular, a stochastic background of PMF has a fully non-Gaussian contribution to CMB anisotropies and induce a non-zero bispectrum. We have derived the CMB magnetized bispectrum generated by scalar magnetized perturbations on large angular scales and we have derived the constraints on PMF with current non-Gaussianity data, we show that these constraints are comparable to the ones derived with CMB angular power spectrum data. The second part of the thesis is devoted to the investigation of the im¬pact of foreground and secondary anisotropy residuals on small scales on the cosmological parameters with Planck data. In particular the contributions which are relevant for Planck frequencies and capabilities are: the residual point source contributions and the residual Sunyaev Zeldovcih effect. For what concerns the point source contribution we have considered both the Poissonian term for all unresolved sources and the clustering term for the infrared galaxies. In order to marginalize over the residual contributions in cosmological parameters extraction, we have developed hybrid theoretical/empirical parametrizations for each residual considered. Together with the spectral shape of the sig¬nals it is parametrized also their frequency dependence, this allowed the reductio n of the number of parameters necessary to describe the residuals to the minimum of three, one for each contribution. We have developed an extension of the CAMB+CosmoMC code which includes the marginalization over the considered residual contributions with the approach we have presented. The code is used to investigate the impact of the foreground and secondary anisotropy residuals on the cosmological parameters and in particular, the results show the importance of the marginalization in order to not introduce biases. In the thesis it is addressed also the topic of the frequency channel combination. In particular, we have developed an original empirical method to combine the frequency channels. We show the comparison between the results obtained with this technique and the ones obtained with the standard inverse noise variance weighting method
Reactive transport of pollutants in porous media
No full textAccidental or deliberate crude oil spills have been, and still continue to be, a significant source of environmental pollution, and pose a serious environmental problem, due to the possibility of air, water and soil contamination. Chlorinated volatile organic compounds (VOCs), such as 1,1-dichloroethylene (DCE) and aromatic hydrocarbons, BTEX (benzene, toluene, ethyl benzene and xylene) constitute a significant fraction of hazardous air and water pollution. Human beings are exposed to elevated levels of a wide spectrum of VOCs, many of which have been found to be toxic and potentially carcinogenic. Removal of these organic contaminants from water and wastewater has been achieved using several treatment technologies, such as advanced oxidation processes, air stripping, reverse osmosis, ultrafiltration and adsorption. Adsorption processes can be successfully used when contaminants are not amenable to fast biological degradation. Permeable Reactive Barriers (PRB) are one of the most promising passive treatment technologies, due to their effectiveness regarding various contaminants, and their low cost compared to other in situ technologies. Typical PRB configuration consists in a permeable treatment zone placed vertically to the flow path of groundwater, which contains reactive material that immobilises or decomposes the contaminants by adsorption as the groundwater flows through it. PRBs are installed as permanent, semi-permanent, or replaceable units. A wide variety of pollutants are degraded, precipitated, sorbed or exchanged in the reactive zone, including chlorinated solvents, heavy metals, radionuclides and other organic and inorganic species. Conventional permeable reactive barriers for the decontamination of water are based on systems which most widely use Granular Activated Carbon (GAC). GAC has been shown to be only slightly effective in treating water containing very soluble compounds, such as oxygenated organics, or low molecular weight compounds, such as DCE and vinyl chloride (VC). However, their use for the removal of organic contaminants in water and wastewater applications can be complicated by the presence of dissolved natural organic matter in the water stream being treated, which can decrease the removal efficiency of GAC. When activated carbon is saturated, it has to be regenerated or renewed, which is rather an expensive operation. The adsorbed molecules are then released and still have to be destroyed by thermal treatments. Moreover, this additional treatment also degrades the activated carbon adsorption properties in the long term [1]. Zero-valent iron (ZVI), which directly degrades several contaminants, appears to be ineffective too, both on irreducible compounds such as DCE and chlorobenzenes as well as on hydrocarbons. Furthermore, when ZVI is used, it causes a reduction in the permeability of the barrier due to encrustations or precipitation of minerals which derive from the reactions between the ions of the oxidised metal and the substances contained in the groundwater [1-2]. Therefore, when operating with a barrier based on metallic iron alone, the chemical reduction reaction of the reducible compounds can require from 1 to 2 days. In this case, it is only the thickness of the iron which can ensure the time necessary for completing the reactions and large quantities are required to guarantee the complete decontamination of the groundwater. Recently, high-silica zeolites were shown to be more effective than activated carbon or ZVI in removing certain organics from water [3-4]. The selection of zeolites from among the large variety of adsorbent materials is based on their stability and efficiency properties. To date, the adsorption mechanisms of zeolites in gas phase systems have been widely investigated. On the contrary, studies and applications on organic pollutants adsorption in microporous zeolitic materials from aqueous media have been relatively scarce. Adsorption from gas phase systems can significantly differ from that observed from the corresponding aqueous solutions, due to the highly polar nature of water molecules. In literature, it has been reported that water plays a very important role in the diffusion of hydrocarbons in the zeolite pore system. In particular, large amounts of co-adsorbed water molecules block the migration of host molecules such as alkanes and olefins, thus reducing the adsorption capacity of zeolites, especially at low adsorbate concentrations. As a consequence, water acts as a screen between the cationic sites of the zeolite and the hydrocarbon molecules (screening effect) and reduces both the sorption volume (steric effect) and the aperture of the zeolite windows (blocking effect). On the contrary, small amounts of co-adsorbed water lower the extent of specific adsorption without significant blocking effects. However, as mentioned above, this research on hydrocarbon adsorption has also mainly been focused on single components from air matrices, whereas there are few studies involving aqueous dilute solutions. Nonetheless, in most environmental applications, these pollutants are present as very dilute aqueous solution mixtures. The work developed in the present thesis is part of a wider project whose purpose is to study the interaction and mobility of groundwater pollutants adsorbed in zeolite pores, in order to improve the efficiency of permeable reactive barriers. This project involves Ferrara and Bologna Universities with the financial support of the ENI and the scientific support of Dr. Roberto Bagatin of the research centre of Novara. Several techniques were employed such as X ray diffraction, gas chromatography, IR spectroscopy, thermal analyses, as well as computational studies. In this thesis, combined diffractometric, thermogravimetric and gas chromatographic techniques were employed to study the adsorption process in order to: 1) investigate the adsorptive properties of these hydrophobic synthetic zeolites; 2) characterise their structure after the adsorption of selected contaminants (1-2 dichloroethane, tert-butyl methyl ether and toluene); 3) localise the organic species in the zeolite channel system; 4) probe the interactions between organic molecules and framework oxygen atoms; 5) compare the adsorption data for a mixture of these contaminants with concentrations in the ppb and ppm range; 6) characterise the kinetic of the adsorption processes. In particular, the thermodynamic and kinetic of the adsorption processes of contaminants on hydrophobic zeolites were obtained by using complementary, batch, linear and non-linear chromatography and thermogravimetry techniques. Batch and non-linear chromatography were mainly used to measure the adsorption isotherms for the compounds of interest. The adsorption isotherm is useful in representing the capacity of a zeolite to adsorb organics from waste, and in providing description of the functional dependence of capacity on the concentration of pollutants. Experimental determination of the isotherm allows to evaluate the feasibility of adsorption for treatment, to select a zeolite, and to estimate adsorbent dosage requirements. Moreover, it is possible to evaluate the adsorption energy distribution of the process from isotherm parameters. Batch and linear chromatography, instead, were employed to investigate the kinetic of the adsorption. Kinetics deals with changes in chemical properties in time and is especially concerned with the rate of changes and plays a fundamental role in determining the proper time contact for the removal of pollutant components from wastewater. In addition, an original theoretical model able to give information regarding the kinetic and the thermodynamic constants of systems in which both reactions and adsorption processes occur simultaneously was developed. To investigate the adsorption mechanism, diffraction techniques were employed to localize the organics adsorbed into the zeolite structure. The information gathered by this latter investigation – in cooperation with the Earth Science Department UNIFE - allows to define the interactions between organic molecules and zeolite framework. Finally, adsorption on mesoporous materials was investigated. It is well known that water is contaminated by different classes of substances, and zeolites are mainly suitable for molecules with dimensions comparable to that of their pores. However, many compounds belonging to the class of emergent contaminants have large molecular dimensions, and in such cases mesoporous materials can be more efficient than zeolites. To accomplish this task MCM-41 and HMS were synthesized and characterised – this work was carried out at the ‘Institut Charles Gerhardt (ICG), Matériaux Avancés pour la Catalyse et la Santé (MACS)’ at Montpellier (France) with the supervision of Prof. Francesco di Renzo and Dr. Anne Galarneau – and then the adsorption of acid perfluorooctanoic onto these mesoporous materials was performed.Accidental or deliberate crude oil spills have been, and still continue to be, a significant source of environmental pollution, and pose a serious environmental problem, due to the possibility of air, water and soil contamination. Chlorinated volatile organic compounds (VOCs), such as 1,1-dichloroethylene (DCE) and aromatic hydrocarbons, BTEX (benzene, toluene, ethyl benzene and xylene) constitute a significant fraction of hazardous air and water pollution. Human beings are exposed to elevated levels of a wide spectrum of VOCs, many of which have been found to be toxic and potentially carcinogenic. Removal of these organic contaminants from water and wastewater has been achieved using several treatment technologies, such as advanced oxidation processes, air stripping, reverse osmosis, ultrafiltration and adsorption. Adsorption processes can be successfully used when contaminants are not amenable to fast biological degradation. Permeable Reactive Barriers (PRB) are one of the most promising passive treatment technologies, due to their effectiveness regarding various contaminants, and their low cost compared to other in situ technologies. Typical PRB configuration consists in a permeable treatment zone placed vertically to the flow path of groundwater, which contains reactive material that immobilises or decomposes the contaminants by adsorption as the groundwater flows through it. PRBs are installed as permanent, semi-permanent, or replaceable units. A wide variety of pollutants are degraded, precipitated, sorbed or exchanged in the reactive zone, including chlorinated solvents, heavy metals, radionuclides and other organic and inorganic species. Conventional permeable reactive barriers for the decontamination of water are based on systems which most widely use Granular Activated Carbon (GAC). GAC has been shown to be only slightly effective in treating water containing very soluble compounds, such as oxygenated organics, or low molecular weight compounds, such as DCE and vinyl chloride (VC). However, their use for the removal of organic contaminants in water and wastewater applications can be complicated by the presence of dissolved natural organic matter in the water stream being treated, which can decrease the removal efficiency of GAC. When activated carbon is saturated, it has to be regenerated or renewed, which is rather an expensive operation. The adsorbed molecules are then released and still have to be destroyed by thermal treatments. Moreover, this additional treatment also degrades the activated carbon adsorption properties in the long term [1]. Zero-valent iron (ZVI), which directly degrades several contaminants, appears to be ineffective too, both on irreducible compounds such as DCE and chlorobenzenes as well as on hydrocarbons. Furthermore, when ZVI is used, it causes a reduction in the permeability of the barrier due to encrustations or precipitation of minerals which derive from the reactions between the ions of the oxidised metal and the substances contained in the groundwater [1-2]. Therefore, when operating with a barrier based on metallic iron alone, the chemical reduction reaction of the reducible compounds can require from 1 to 2 days. In this case, it is only the thickness of the iron which can ensure the time necessary for completing the reactions and large quantities are required to guarantee the complete decontamination of the groundwater. Recently, high-silica zeolites were shown to be more effective than activated carbon or ZVI in removing certain organics from water [3-4]. The selection of zeolites from among the large variety of adsorbent materials is based on their stability and efficiency properties. To date, the adsorption mechanisms of zeolites in gas phase systems have been widely investigated. On the contrary, studies and applications on organic pollutants adsorption in microporous zeolitic materials from aqueous media have been relatively scarce. Adsorption from gas phase systems can significantly differ from that observed from the corresponding aqueous solutions, due to the highly polar nature of water molecules. In literature, it has been reported that water plays a very important role in the diffusion of hydrocarbons in the zeolite pore system. In particular, large amounts of co-adsorbed water molecules block the migration of host molecules such as alkanes and olefins, thus reducing the adsorption capacity of zeolites, especially at low adsorbate concentrations. As a consequence, water acts as a screen between the cationic sites of the zeolite and the hydrocarbon molecules (screening effect) and reduces both the sorption volume (steric effect) and the aperture of the zeolite windows (blocking effect). On the contrary, small amounts of co-adsorbed water lower the extent of specific adsorption without significant blocking effects. However, as mentioned above, this research on hydrocarbon adsorption has also mainly been focused on single components from air matrices, whereas there are few studies involving aqueous dilute solutions. Nonetheless, in most environmental applications, these pollutants are present as very dilute aqueous solution mixtures. The work developed in the present thesis is part of a wider project whose purpose is to study the interaction and mobility of groundwater pollutants adsorbed in zeolite pores, in order to improve the efficiency of permeable reactive barriers. This project involves Ferrara and Bologna Universities with the financial support of the ENI and the scientific support of Dr. Roberto Bagatin of the research centre of Novara. Several techniques were employed such as X ray diffraction, gas chromatography, IR spectroscopy, thermal analyses, as well as computational studies. In this thesis, combined diffractometric, thermogravimetric and gas chromatographic techniques were employed to study the adsorption process in order to: 1) investigate the adsorptive properties of these hydrophobic synthetic zeolites; 2) characterise their structure after the adsorption of selected contaminants (1-2 dichloroethane, tert-butyl methyl ether and toluene); 3) localise the organic species in the zeolite channel system; 4) probe the interactions between organic molecules and framework oxygen atoms; 5) compare the adsorption data for a mixture of these contaminants with concentrations in the ppb and ppm range; 6) characterise the kinetic of the adsorption processes. In particular, the thermodynamic and kinetic of the adsorption processes of contaminants on hydrophobic zeolites were obtained by using complementary, batch, linear and non-linear chromatography and thermogravimetry techniques. Batch and non-linear chromatography were mainly used to measure the adsorption isotherms for the compounds of interest. The adsorption isotherm is useful in representing the capacity of a zeolite to adsorb organics from waste, and in providing description of the functional dependence of capacity on the concentration of pollutants. Experimental determination of the isotherm allows to evaluate the feasibility of adsorption for treatment, to select a zeolite, and to estimate adsorbent dosage requirements. Moreover, it is possible to evaluate the adsorption energy distribution of the process from isotherm parameters. Batch and linear chromatography, instead, were employed to investigate the kinetic of the adsorption. Kinetics deals with changes in chemical properties in time and is especially concerned with the rate of changes and plays a fundamental role in determining the proper time contact for the removal of pollutant components from wastewater. In addition, an original theoretical model able to give information regarding the kinetic and the thermodynamic constants of systems in which both reactions and adsorption processes occur simultaneously was developed. To investigate the adsorption mechanism, diffraction techniques were employed to localize the organics adsorbed into the zeolite structure. The information gathered by this latter investigation – in cooperation with the Earth Science Department UNIFE - allows to define the interactions between organic molecules and zeolite framework. Finally, adsorption on mesoporous materials was investigated. It is well known that water is contaminated by different classes of substances, and zeolites are mainly suitable for molecules with dimensions comparable to that of their pores. However, many compounds belonging to the class of emergent contaminants have large molecular dimensions, and in such cases mesoporous materials can be more efficient than zeolites. To accomplish this task MCM-41 and HMS were synthesized and characterised – this work was carried out at the ‘Institut Charles Gerhardt (ICG), Matériaux Avancés pour la Catalyse et la Santé (MACS)’ at Montpellier (France) with the supervision of Prof. Francesco di Renzo and Dr. Anne Galarneau – and then the adsorption of acid perfluorooctanoic onto these mesoporous materials was performed
Lattice relaxation in solid solutions: long-range vs. short-range structure around Cr3+ and Co2+ in oxides and silicates
No full textThis dissertation reports the results derived from the 3-year doctoral thesis project aimed at exploring some oxide and silicate structures as promising ceramic pigments with enhanced colorimetric properties with respect to the traditional colorants. Solid solutions of perovskite, alumoniobite, and melilite compounds were obtained by doping octahedral and tetrahedral coordination sites with transition metal ions (e.g. Cr3+, Co2+, and Zn2) through a solid-state synthesis performed by means of an industrial-like process. The analytical techniques adopted to investigate the synthesized compounds allowed the determination of the "averaged" crystal structure, or the so termed long-range properties, and the short-range properties (i.e. the local structure around the substituting ions) through X-ray powder diffraction and electron absorption spectroscopy (EAS), respectively. As stated by Geiger (2001) "an understanding of the microscopic, mesoscopic and macroscopic properties and of the behaviour of solid solutions under different conditions is a challenge for all disciplines concerned with the solid state". As a matter of fact, the precise determination of a structure around impurities results fundamental to provide detailed information on their incorporation and on physical properties. For instance, in the case of the solid solutions here reported, the lattice incorporation of transition metal ions as impurities is the cause of their gradual coloration. Most of the times, such a coloration is more intense as greater is the impurity amount. The final goal of this work, was attained by calculating the structural relaxation coefficient for each studied solid solution by combining the mean with the local bond distances achieved by XRPD and EAS, respectively.This dissertation reports the results derived from the 3-year doctoral thesis project aimed at exploring some oxide and silicate structures as promising ceramic pigments with enhanced colorimetric properties with respect to the traditional colorants. Solid solutions of perovskite, alumoniobite, and melilite compounds were obtained by doping octahedral and tetrahedral coordination sites with transition metal ions (e.g. Cr3+, Co2+, and Zn2) through a solid-state synthesis performed by means of an industrial-like process. The analytical techniques adopted to investigate the synthesized compounds allowed the determination of the "averaged" crystal structure, or the so termed long-range properties, and the short-range properties (i.e. the local structure around the substituting ions) through X-ray powder diffraction and electron absorption spectroscopy (EAS), respectively. As stated by Geiger (2001) "an understanding of the microscopic, mesoscopic and macroscopic properties and of the behaviour of solid solutions under different conditions is a challenge for all disciplines concerned with the solid state". As a matter of fact, the precise determination of a structure around impurities results fundamental to provide detailed information on their incorporation and on physical properties. For instance, in the case of the solid solutions here reported, the lattice incorporation of transition metal ions as impurities is the cause of their gradual coloration. Most of the times, such a coloration is more intense as greater is the impurity amount. The final goal of this work, was attained by calculating the structural relaxation coefficient for each studied solid solution by combining the mean with the local bond distances achieved by XRPD and EAS, respectively
Le sfide competitive dei sistemi maturi nel mercato globale. Innovazione e cambiamento istituzionale nel modello emiliano
No full textThe competition challenge of the mature systems in the global market. Innovation and institutional change in the Emilian model. Competitiveness is defined as capability to satisfy a potential demand, or ability to produce by a technology. For this reason, issues related to the territorial organization of production and to the industry life cycle are overlapped. In fact, the possibilities to use a technology strictly depend on the ways of production organization and, when production is a local matter, also the technology becomes local. Localized systems of production are just defined by this overlapping and, once a dominant technological paradigm is arisen, they turn in mature ones, i.e. they have to cope with a competition paradox. The only solution is an increase in the division of labour getting the territory to take a new technological path and start a new development process. This process goes through a system shake-out expanding the set of productive relations in the direction of an institutional division of labour, because maturity represents the depletion of a «work to be done» that is also the reaching of the full divisibility of labour. Hence, production processes have to be opened to new players that must be able to use the same local technology. These ones are the institutions that by «functional spin-offs» are entitled to participate to the production. Thus, the territory becomes a «territorial platform of production»The competition challenge of the mature systems in the global market. Innovation and institutional change in the Emilian model. Competitiveness is defined as capability to satisfy a potential demand, or ability to produce by a technology. For this reason, issues related to the territorial organization of production and to the industry life cycle are overlapped. In fact, the possibilities to use a technology strictly depend on the ways of production organization and, when production is a local matter, also the technology becomes local. Localized systems of production are just defined by this overlapping and, once a dominant technological paradigm is arisen, they turn in mature ones, i.e. they have to cope with a competition paradox. The only solution is an increase in the division of labour getting the territory to take a new technological path and start a new development process. This process goes through a system shake-out expanding the set of productive relations in the direction of an institutional division of labour, because maturity represents the depletion of a «work to be done» that is also the reaching of the full divisibility of labour. Hence, production processes have to be opened to new players that must be able to use the same local technology. These ones are the institutions that by «functional spin-offs» are entitled to participate to the production. Thus, the territory becomes a «territorial platform of production
The Latin Language in Roman Juridical Inscriptions ‘Iustitia’ in the ‘Res gestae’
No full textThe text analyzes iustitia in the Monumentum Ancyranum in the ideology of imperial power, according to a perspective that values meaning and signifier, that is content and epigraphic support in the legal history of ‘royal’ writing between Ancient Near East and West.Il testo analizza la iustitia nel Monumentum Ancyranum nell\u27ideologia del potere imperiale, secondo una prospettiva che valorizza significato e significante, cioè contenuto e supporto epigrafico nella storia giuridica della scrittura “regale” tra Vicino Oriente antico e Occidente