3,572 research outputs found
Manuale di diritto penale. Parte generale
No full textQuinta edizione del Manuale di diritto penale. Parte generale di G. Marinucci ed E. Dolcini, aggiornata, dopo la scomparsa di G. Marinucci, da E. Dolcini e G.L. Gatta
Crystal-fluid interactions in open-framework silicates
No full textThe structural evolution of microporous materials compressed hydrostatically in a fluid is drastically affected by the potential crystal-fluid interaction, with a penetration of new molecular species through the zeolitic voids in response to applied pressure.
On the basis of recent experimental findings and computational modelling studies, it was observed that when no crystal-fluid interaction occurs, the effects of pressure are mainly accommodated by tilting of (quasi-rigid) tetrahedra around the bridging O atoms. Tilting of tetrahedra is the dominant mechanisms at low-mid P-regime, whereas distortion and compression of tetrahedra dominate the mid-high P regime. The deformation mechanisms are governed by the topological configuration of the tetrahedral framework, but the compressibility of the cavities is controlled by the ionic and molecular host content, resulting in different unit-cell volume compressibility in isotypic structures. One of the most common deformation mechanisms in zeolitic framework is the increase of channels ellipticity.
Not all the zeolites experience a P-induced intrusion of new monoatomic species or molecules from the P-transmitting fluids. For example, natural zeolites, with well-stuffed channels at room conditions, tend to hinder the penetration of new species through the zeolitic voids. Several variables govern the sorption phenomena at high pressure: the “free diameters” of the framework cavities, the configuration of the extraframework population, the partial pressure of the penetrating molecule in the fluid (if mixed with other nonpenetrating molecules), the rate of P-increase, the surface/volume ratio of the crystallites under investigations, the temperature at which the experiment is conducted. The most recent findings allow us to provide an overview of the intrusion phenomena of monoatomic species (e.g., He, Ar, Kr), small (e.g., H2O, CO2) and complex molecules, along with the P-induced polymerization phenomena, (e.g., C2H2, C2H4, C2H6O, C2H6O2, BNH6, electrolytic MgCl2·21H2O solution), with potential technological and geological implications.
Gatta, G.D. (2008): Does porous mean soft? On the elastic behaviour and structural evolution of zeolites under pressure.
Z. Kristallogr., 223, 160-170.
Gatta, G.D. & Lee, Y. (2014): Zeolites at high pressure: A review. Mineral. Mag., 78, 267-291.
Gatta, G.D., Lotti, P. & Tabacchi, G. (2017): The effect of pressure on open-framework silicates: elastic behaviour and
crystal-fluid interaction. Phys. Chem. Minerals, 45, 115-138
A low temperature X-ray single-crystal diffraction and polarised infra-red study of epidote
No full textThe effects of low-temperature on the crystal structure of a natural epidote [Ca1.925Fe0.745Al2.265Ti0.004 Si3.037O12(OH), a = 8.8924(7), b = 5.6214(3), c = 10.1547(6) angstrom and beta = 115.396(8)degrees at room conditions, Sp. Gr. P2(1)/m] have been investigated with a series of structure refinements down to 100 K on the basis of X-ray single-crystal diffraction data. The reflection conditions confirm that the space group is maintained within the T-range investigated. Structural refinements at all temperatures show the presence of Fe3+ at the octahedral M(3) site only [%Fe(M3) = 70.6(4)% at 295 K]. Only one independent proton site was located and two possible H-bonds occur, with O(10) as donor and O(4) and O(2) as acceptors. The H-bonding scheme is maintained down to 100 K and is supported by single crystal room-T polarised FTIR data. FTIR Spectra over the region 4,000-2,500 cm(-1) are dominated by the presence of a strongly pleochroic absorption feature which can be assigned to protonation of O(10)-O(4). Previously unobserved splitting of this absorption features is consistent with a NNN influence due to the presence of Al and Fe3+ on the nearby M(3) site. An additional relatively minor absorption feature in FTIR spectra can be tentatively assigned to protonation of O(10)-O(2). Low-T does not affect significantly the tetrahedral and octahedral bond distances and angles, even when distances are corrected for "rigid body motions". A more significant effect is observed for the bond distances of the distorted Ca(1)- and Ca(2)-polyhedra, especially when corrected for "non-correlated motion". The main low-T effect is observed on the vibrational regime of the atomic sites, and in particular for the two Ca-sites. A significant reduction of the magnitude of the thermal displacement ellipsoids, with a variation of U-eq (defined as one-third of the trace of the orthogonalised U-ij tensor) by similar to 40% is observed for the Ca-sites between 295 and 100 K. Within the same T-range, the U-eq of the octahedral and oxygen sites decrease similarly by similar to 35%, whereas those of the tetrahedral cations by similar to 22%.</p
Va punito chi fa reati, non chi potrebbe farli : ecco tutte le incognite dell'agente provocatore
No full textLettera al Direttore del Corriere della Sera inviata dal Presidente dell'Autorità Nazionale Anticorruzione, Dott. Raffaele Cantone, e dal Prof. Gian Luigi Gatta (Ordinario di Diritto penale nell'Università degli Studi di Milano) , sul tema dell'utilizzo di agenti provocatori nel contrasto alla corruzione
La pena nell'era della 'crimmigration': tra Europa e Stati Uniti
No full textLa criminalizzazione dell’immigrazione irregolare rappresenta da anni, su scala internazionale, un inarrestabile trend politico-criminale, alimentato sempre più da istanze di sicurezza nazionale connesse all’esplosione di fenomeni correlati, a partire dal terrorismo di matrice islamica. Non si tratta tanto e solo di configurare come reato la ‘clandestinità’, bensì di inquadrare un complesso fenomeno che, nella recente letteratura internazionale, va sotto il nome di ‘crimmigration’. Con questo neologismo si allude alla sovrapposizione o intersezione tra il diritto penale e il diritto dell’immigrazione in
funzione di almeno tre convergenti strategie politico-criminali: a) la previsione di conseguenze penalistiche (pene
detentive e/o pecuniarie) per violazioni del diritto dell’immigrazione; b) la previsione di conseguenze amministrativistiche connesse a condanne penali (mancata ammissione nello Stato ed espulsione); c) il ricorso a misure privative o limitative della libertà personale di tipo penalistico (arresto e detenzione funzionale all’espulsione) nell’ambito del diritto
dell’immigrazione. Ne risulta un sistema ibrido, ai confini di quello penale, che prende in prestito dal diritto penale tecniche e strumenti di tutela degli interessi pubblici in gioco ma, al tempo stesso, dimentica intenzionalmente di importare le garanzie del sistema della giustizia penale, sacrificate sull’altare della maggiore efficacia e speditezza dell’azione di contrasto all’immigrazione irregolare e alla connessa criminalità. La lotta contro quei fenomeni, emergenziali, viene infatti oggi per lo più condotta, in Europa e negli Stati Uniti, attraverso misure e agenzie di enforcement del diritto dell’immigrazione, che della pena non hanno la forma e le correlate garanzie, ma hanno spesso la sostanza
Introduzione
No full textL'Introduzione di Elide casali traccia le coordinate cronologiche (età moderna, l"'età dei maghi" secondo la definizione di Paolo Rossi), spaziali (Romagna) e culturali (scienza e letteratura) cui si riferiscono i saggi elaborati da una serie di collaboratori ( F. Bacchelli, G. Cerasoli, L. Michelacci, F. Gatta, A. Natale, M. Carreras, G. Ernst, E. Zinato, G. Olmi, M. Prandi) su una serie di testi e fonti presenti nelle Raccolte Piancastelli conservate presso la Biblioteca Comunale"A. Saffi" di Forlì"
“Half Devil and Half Child”: An Ethnographic Perspective on the Treatment of Migrants on their Arrival in Lampedusa
No full textBased on a long-term fieldwork started in 2005, this essay will discuss the biopolitical management of migrants intercepted in the Mediterranean Sea by the Italian authorities. The direct ethnographic experience of the author on the harbour dock of Lampedusa will permit to focus on the “body” of migrants as well as on the “bodies” of the other actors involved in the dynamics at work during the “landing” phase. The disciplining, caring and observation practices by guards, humanitarian actors, media and locals will be examined, as well as the presentation of the self performed by migrants, the practices of negotiating pain, the management of space during the “landing” procedures, the active role of border guards in evoking or directly producing a specific image of the “arrivals”
Lampedusa, 3 ottobre 2013. Vita, morte, nazione e politica nella gestione delle migrazioni
No full textOn 3rd October 2013 hundreds of Europe-bound people lost their lives in the sea off Lampedusa. Although tragedies of this type have been occurring for at least a couple of decades, the significance of this event has triggered reactions from both Italian civil society and organizations of exiles. The Italian institutions have once again framed the phenomenon through a «securitarian» and «humanitarian» approach. Their behaviour towards the dead people, the survivors and the victims' parents has been characterized by «avoiding» and «suppression» (especially celebrating a funeral in the absence of the survivors and the parents). From their point of view the Eritrean exiles (the majority of those involved in the tragedy) - together with sectors of the Italian civil society - spoke out against the Eritrean regime and the Italian assistance to it. Their statement has made clear the political and postcolonial dimension of the event. Along these lines the border crossing appears as a challenge to the traditional idea of citizenship based on the inclusion/exclusion dichotomy
Clandestinità e luoghi terzi. Legittimazione, sicurezza, soggettività
No full textBased on a specific sense of the concept of «clandestinity» - as a potential deportability which hangs over the whole migrant population - the article aims at exploring the effects that the peculiar condition of clandestinity produces on the relationship between migrants and «third places» - i.e. multipurpose spaces intermediate between domestic space and workplace: cafes, bars, taverns, squares, etc. It is proposed an analysis that starting from places of disciplination such as the dock in the port of Lampedusa (Sicily) - a place symbolizing the negation of subjectivity, where a specific image of migrant bodies has been shaped over time - comes up with a reflection on possible places where migrants' condition and experience could find a listening context. Such a context is supposed to guarantee to migrants' narrations the dignity of political and poetic expression, as a precondition for the emergence of a public sphere. During the intermediate stages of this path we will focus on the mode of attendance of cafes and bars from a transnational perspective, focussing in particular on the mechanisms of legitimation migrants are subject to, and on the specific form of attendance of third places during the so called «clandestine trip», where peculiar security problems arise
P-induced crystal fluid interaction: the case of ERI and OFF topology
No full textThe P-induced intrusion of molecules or solvated ions within the nanocavities of open-framework minerals, such as zeolites, has been extensively investigated during last decades (e.g., Gatta et al., 2018, and references within). This peculiar property might be exploited to tailor new multifunctional materials or to enhance industrial catalytic processes involving zeolites (Comboni et al., 2020). In addition, from a geological point
of view, a constraint of this phenomena might shed light on the role played by zeolites as fluid carriers in the upper Earth crust, e.g., during the early subduction of altered basalts or oceanic sediments. The aim of the present study is to characterize the high-pressure behavior, promoting the crystal-fluid interaction, on two different natural zeolites species belonging to the ABC-6 family: erionite (AABAAC) and offretite (AAB)
(ERI and OFF topology, respectively). Similarities of the framework between these two species resulted in quite common intergrowth, at least in natural samples (Passaglia et al., 1998). Samples were compressed in non-penetrating and penetrating P-transmitting fluids (PTFs). Investigations were conducted via in-situ high pressure single-crystal synchrotron X-ray diffraction, using a diamond anvil cell (DAC), at the ID15b beamline of ESRF (Grenoble, France) and P02.2 of PETRA-III (Hamburg, Germany). Different PTFs have been employed during the experiments: non-penetrating i) silicone oil and daphne oil (7575) and potentially penetrating, ii) alcohols: water mixtures, iii) pure H2O, iv) Ne. The obtained unit-cell P-V patterns revealed the adsorption of H2O molecules within the structural cavities; in addition, the structure refinements allowed to describe the deformation mechanisms as well as the location of the adsorbed molecules. Interestingly, the magnitude of the absorption phenomena in natural erionite appeared to be comparable with what observed in synthetic zeolites (i.e., AlPO4-5, Lotti et al., 2016), highlighting the great potential of erionite as a mineralogical carrier of fluids in the upper Earth crust.
Comboni D., Pagliaro F., Lotti P., Gatta G.D., Merlini M., Milani S., Migliori M., Giordano G., Catizzone E., Collings I.E. & Hanfland M. (2020) - The elastic behavior of zeolitic frameworks: The case of MFI type zeolite under high-pressure methanol intrusion. Catal. Today, 345, 88-96.
Gatta G.D., Lotti P. & Tabacchi G. (2018) - The effect of pressure on open-framework silicates: elastic behaviour and crystal-fluid interaction. Phys. Chem. Miner., 45, 115-138.
Lotti P., Gatta G.D., Comboni., Merlini M., Pastero L. & Hanfland M. (2016) - AlPO4-5 zeolite at high pressure: Crystalfluid interaction and elastic behavior. Microp. Mesop. Mater., 228, 158-167.
Passaglia E., Artioli G. & Gualtieri A. (1998) - Crystal chemistry of the zeolites erionite and offretite. Am. Mineral., 83, 577-589
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