Use of solvents and environmental friendly materials for applications in Green Chemistry

The present Thesis studies three alternative solvent groups as sustainable replacement of traditional organic solvents. Some aspects of fluorinated solvents, supercritical fluids and ionic liquids, have been analysed with a critical approach and their effective “greenness” has been evaluated from the points of view of the synthesis, the properties and the applications. In particular, the attention has been put on the environmental and human health issues, evaluating the eco-toxicity, the toxicity and the persistence, to underline that applicability and sustainability are subjects with equal importance. The “green” features of fluorous solvents and supercritical fluids are almost well-established; in particular supercritical carbon dioxide (scCO2) is probably the “greenest” solvent among the alternative solvent systems developed in the last years, enabling to combine numerous advantages both from the point of view of industrial/technological applications and eco-compatibility. In the Thesis the analysis of these two classes of alternative solvents has been mainly focused on their applicability, rather than the evaluation of their environmental impact. Specifically they have been evaluated as alternative media for non-aqueous biocatalysis. For this purpose, the hydrophobic ion pairing (HIP), which allows solubilising enzymes in apolar solvents by an ion pairing between the protein and a surfactant, has been investigated as effective enzymatic derivatisation technique to improve the catalytic activity under homogeneous conditions in non conventional media. The results showed that the complex enzyme-surfactant was much more active both in fluorous solvents and in supercritical carbon dioxide than the native form of the enzyme. Ionic liquids, especially imidazolium salts, have been proposed some years ago as “fully green” alternative solvents; however this epithet does not take into account several “brown” aspects such as their synthesis from petro-chemical starting materials, their considerable eco-toxicity, toxicity and resistance to biodegradation, and the difficulty of clearly outline applications in which ionic liquids are really more advantageous than traditional solvents. For all of these reasons in this Thesis a critical analysis of ionic liquids has been focused on three main topics: i) alternative synthesis by introducing structural moieties which could reduce the toxicity of the most known liquid salts, and by using starting materials from renewable resources; ii) on the evaluation of their environmental impact through eco-toxicological tests (Daphnia magna and Vibrio fischeri acute toxicity tests, and algal growth inhibition), toxicity tests (MTT test, AChE inhibition and LDH release tests) and fate and rate of aerobic biodegradation in soil and water; iii) and on the demonstration of their effectiveness as reaction media in organo-catalysis and as extractive solvents in the recovery of vegetable oil from terrestrial and aquatic biomass. The results about eco-toxicity tests with Daphnia magna, Vibrio fischeri and algae, and toxicity assay using cultured cell lines, clearly indicate that the difference in toxicity between alkyl and oxygenated cations relies in differences of polarity, according to the general trend of decreasing toxicity by decreasing the lipophilicity. Independently by the biological approach in fact, all the results are in agreement, showing a lower toxicity for compounds with oxygenated lateral chains than for those having purely alkyl lateral chains. These findings indicate that an appropriate choice of cation and anion structures is important not only to design the IL with improved and suitable chemico-physical properties but also to obtain safer and eco-friendly ILs. Moreover there is a clear indication that the composition of the abiotic environment has to be taken into account when the toxicity of ILs in various biological test systems is analysed, because, for example, the data reported in the Thesis indicate a significant influence of salinity variations on algal toxicity. Aerobic biodegradation of four imidazolium ionic liquids, two alkylated and two oxygenated, in soil was evaluated for the first time. Alkyl ionic liquids were shown to be biodegradable over the 6 months test period, and in contrast no significant mineralisation was observed with oxygenated derivatives. A different result was observed in the aerobic biodegradation of alkylated and oxygenated pyridinium ionic liquids in water because all the ionic liquids were almost completely degraded after 10 days, independently by the number of oxygen in the lateral chain of the cation. The synthesis of new ionic liquids by using renewable feedstock as starting materials, has been developed through the synthesis of furan-based ion pairs from furfural. The new ammonium salts were synthesised in very good yields, good purity of the products and wide versatility, combining low melting points with high decomposition temperatures and reduced viscosities. Regarding the possible applications as surfactants and biocides, furan-based salts could be a valuable alternative to benzyltributylammonium salts and benzalkonium chloride that are produced from non-renewable resources. A new procedure for the allylation of ketones and aldehydes with tetraallyltin in ionic liquids was developed. The reaction afforded high yields both in sulfonate-containing ILs and in ILs without sulfonate upon addition of a small amount of sulfonic acid. The checked reaction resulted in peculiar chemoselectivity favouring aliphatic substrates towards aromatic ketones and good stereoselectivity in the allylation of levoglucosenone. Finally ILs-based systems could be easily and successfully recycled, making the described procedure environmentally benign. The potential role of switchable polarity solvents as a green technology for the extraction of vegetable oil from terrestrial and aquatic biomass has been investigated. The extraction efficiency of terrestrial biomass rich in triacylglycerols, as soy bean flakes and sunflower seeds, was comparable to those of traditional organic solvents, being the yield of vegetable oils recovery very similar. Switchable polarity solvents as been also exploited for the first time in the extraction of hydrocarbons from the microalga Botryococcus braunii, demonstrating the efficiency of the process for the extraction of both dried microalgal biomass and directly of the aqueous growth medium. The switchable polarity solvents exhibited better extraction efficiency than conventional solvents, both with dried and liquid samples. This is an important issue considering that the harvest and the dewatering of algal biomass have a large impact on overall costs and energy balance.

Theoretical and numerical study of the laser-plasma ion acceleration

The laser driven ion acceleration is a burgeoning field of resarch and is attracting a growing number of scientists since the first results reported in 2000 obtained irradiating thin solid foils by high power laser pulses. The growing interest is driven by the peculiar characteristics of the produced bunches, the compactness of the whole accelerating system and the very short accelerating length of this all-optical accelerators. A fervent theoretical and experimental work has been done since then. An important part of the theoretical study is done by means of numerical simulations and the most widely used technique exploits PIC codes (“Particle In Cell'”). In this thesis the PIC code AlaDyn, developed by our research group considering innovative algorithms, is described. My work has been devoted to the developement of the code and the investigation of the laser driven ion acceleration for different target configurations. Two target configurations for the proton acceleration are presented together with the results of the 2D and 3D numerical investigation. One target configuration consists of a solid foil with a low density layer attached on the irradiated side. The nearly critical plasma of the foam layer allows a very high energy absorption by the target and an increase of the proton energy up to a factor 3, when compared to the ``pure'' TNSA configuration. The differences of the regime with respect to the standard TNSA are described The case of nearly critical density targets has been investigated with 3D simulations. In this case the laser travels throughout the plasma and exits on the rear side. During the propagation, the laser drills a channel and induce a magnetic vortex that expanding on the rear side of the targer is source of a very intense electric field. The protons of the plasma are strongly accelerated up to energies of 100 MeV using a 200PW laser.

Longitudinal evolution of cognitive functions in patients with multiple system atrophy: a prospective study

Introduction and Background: Multiple system atrophy (MSA) is a sporadic, adult-onset, progressive neurodegenerative disease characterized clinically by parkinsonism, cerebellar ataxia, and autonomic failure. We investigated cognitive functions longitudinally in a group of probable MSA patients, matching data with sleep parameters. Patients and Methods: 10 patients (7m/3f) underwent a detailed interview, a general and neurological examination, laboratory exams, MRI scans, a cardiovascular reflexes study, a battery of neuropsychological tests, and video-polysomnographic recording (VPSG). Patients were revaluated (T1) a mean of 16±5 (range: 12-28) months after the initial evaluation (T0). At T1, the neuropsychological assessment and VPSG were repeated. Results: The mean patient age was 57.8±6.4 years (range: 47-64) with a mean age at disease onset of 53.2±7.1 years (range: 43-61) and symptoms duration at T0 of 60±48 months (range: 12-144). At T0, 7 patients showed no cognitive deficits while 3 patients showed isolated cognitive deficits. At T1, 1 patient worsened developing multiple cognitive deficits from a normal condition. At T0 and T1, sleep efficiency was reduced, REM latency increased, NREM sleep stages 1-2 slightly increased. Comparisons between T1 and T0 showed a significant worsening in two tests of attention and no significant differences of VPSG parameters. No correlation was found between neuropsychological results and VPSG findings or RBD duration. Discussion and Conclusions: The majority of our patients do not show any cognitive deficits at T0 and T1, while isolated cognitive deficits are present in the remaining patients. Attention is the cognitive function which significantly worsened. Our data confirm the previous findings concerning the prevalence, type and the evolution of cognitive deficits in MSA. Regarding the developing of a condition of dementia, our data did not show a clear-cut diagnosis of dementia. We confirm a mild alteration of sleep structure. RBD duration does not correlate with neuropsychological findings.

Studio del comportamento meccanico di smalti porcellanati per substrati metallici

Composite porcelain enamels are inorganic coatings for metallic components based on a special ceramic-vitreous matrix in which specific additives are randomly dispersed. The ceramic-vitreous matrix is made by a mixture of various raw materials and elements and in particular it is based on boron-silicate glass added with metal oxides(1) of titanium, zinc, tin, zirconia, alumina, ecc. These additions are often used to improve and enhance some important performances such as corrosion(2) and wear resistance, mechanical strength, fracture toughness and also aesthetic functions. The coating process, called enamelling, depends on the nature of the surface, but also on the kind of the used porcelain enamel. For metal sheets coatings two industrial processes are actually used: one based on a wet porcelain enamel and another based on a dry-silicone porcelain enamel. During the firing process, that is performed at about 870°C in the case of a steel substrate, the enamel raw material melts and interacts with the metal substrate so enabling the formation of a continuous varying structure. The interface domain between the substrate and the external layer is made of a complex material system where the ceramic vitreous and the metal constituents are mixed. In particular four main regions can be identified, (i) the pure metal region, (ii) the region where the metal constituents are dominant compared with the ceramic vitreous components, (iii) the region where the ceramic vitreous constituents are dominant compared with the metal ones, and the fourth region (iv) composed by the pure ceramic vitreous material. It has also to be noticed the presence of metallic dendrites that hinder the substrate and the external layer passing through the interphase region. Each region of the final composite structure plays a specific role: the metal substrate has mainly the structural function, the interphase region and the embedded dendrites guarantee the adhesion of the external vitreous layer to the substrate and the external vitreous layer is characterized by an high tribological, corrosion and thermal shock resistance. Such material, due to its internal composition, functionalization and architecture can be considered as a functionally graded composite material. The knowledge of the mechanical, tribological and chemical behavior of such composites is not well established and the research is still in progress. In particular the mechanical performances data about the composite coating are not jet established. In the present work the Residual Stresses, the Young modulus and the First Crack Failure of the composite porcelain enamel coating are studied. Due to the differences of the porcelain composite enamel and steel thermal properties the enamelled steel sheets have residual stresses: compressive residual stress acts on the coating and tensile residual stress acts on the steel sheet. The residual stresses estimation has been performed by measuring the curvature of rectangular one-side coated specimens. The Young modulus and the First Crack Failure (FCF) of the coating have been estimated by four point bending tests (3-7) monitored by means of the Acoustic Emission (AE) technique(5,6). In particular the AE information has been used to identify, during the bending tests, the displacement domain over which no coating failure occurs (Free Failure Zone, FFZ). In the FFZ domain, the Young modulus has been estimated according to ASTM D6272-02. The FCF has been calculated as the ratio between the displacement at the first crack of the coating and the coating thickness on the cracked side. The mechanical performances of the tested coated specimens have also been related and discussed to respective microstructure and surface characteristics by double entry charts.

La lunga storia dell'idrovia Padova - Venezia

The present dissertation focuses on an unfinished project for the construction of an inland waterway between Padua and Venice, in northern Italy. The history of this channel is analysed in the context of the general debate for the development of a waterway network in the Padanian plain. The project of reconstructing and enlarging the existing ancient channels for the development of a modern river transport system was born at the beginning of the 20th century as an attempt to withstand the railway’s concurrency. The main project aimed at transforming the Po river and other small rivers and channels in a big waterway for the connection of the most important northern industrial cities with Venice’s harbour and the Adriatic sea. Even if the idea of restoring the historical channel between Padua and Venice arose at the end of the First World War, it was only during the years 50s that a new project was conceived and the waterway was included in a global project for the construction of a whole new channel from Venice to Milan. The new project, strongly supported by the local Christian Democratic Party, was managed for more than twenty years causing a huge expenditure of money. After a great investment by both the central State and the local bodies (more than 100 millions euro) the project was finally abandoned. This research reconstructs the historical process and the economical motivations that sustained that project until its failure. Moreover, with the aim of understanding the reasons and the differences of such a failure, the history of inland waterway transport in Italy is compared with contemporary developments in Germany.

Effetto della temperatura di conservazione del latte, dalla raccolta all'affioramento, sulla microflora del latte, del sieroinnesto e del formaggio Trentingrana

This PhD research is part of a project addressed to improve the quality of Grana Trentino production. The objectives were to evaluated if milk storage and collection procedures may affect cheese-making technology and quality. Actually the milk is collected and delivered to the cheese factory just after milking in 50 L cans without refrigeration or in tanks cooled at 18 °C. This procedure is expensive (two deliveries each day) and the milk quality is difficult to preserve as temperatures are not controlled. The milk refrigeration at the farm could allow a single delivery to the dairy. Therefore it could be a good strategy to preserve raw milk quality and reduce cheese spoilage. This operation may, however, have the drawbacks of favouring the growth of psychrotrophic bacteria and changing the aptitude of milk to coagulation. With the aim of studying the effect on milk and cheese of traditional and new refrigerated technologies of milk storage, two different collection and creaming technologies were compared. The trials were replicated in three cheese factories manufacturing Grana Trentino. Every cheese-making day, about 1000 milk liters were collected from always the same two farms in the different collection procedures (single or double). Milk was processed to produce 2 wheels of Grana trentino every day. During the refrigerated trials, milk was collected and stored at the farm in a mixed tank at 12 or 8 °C and then was carried to the dairy in truck once a day. 112 cheese making day were followed: 56 for traditional technology and 56 for the refrigerated one. Each one of these two thechnologies lead to different ways of creaming: long time in the traditional one and shorter in the new one. For every cheese making day we recorded time, temperatures and pH during the milk processing to cheese. Whole milk before ceraming, cream and skim milk after creaming, vat milk and whey were sampled during every cheese-making day for analysis. After 18 months ripening we opened 46 cheese wheels for further chemical and microbiological analyses. The trials were performed with the aim of: 1 estimate the effect of storage temperatures on microbial communities, physico-chemical or/and rheological differences of milk and skim milk after creaming. 2 detect by culture dependent (plate counts) and indipendent (DGGE) methodolgies the microbial species present in whole, skimmed milk, cream and cheese sampled under the rind and in the core; 3 estimate the physico-chemical characteristics, the proteolytic activity, the content of free aminoacids and volatile compounds in 18 months ripened Grana Trentino cheeses from different storing and creaming of milk technologies. The results presented are remarkable since this is the first in-deep study presenting microbiological and chemical analysis of Grana Trentino that even if belonging to Grana Padano Consortium, it is clearly different in the milk and in the manufacturing technology.

Calcolo della posizione di reti di stazioni permanenti

Con il trascorrere del tempo, le reti di stazioni permanenti GNSS (Global Navigation Satellite System) divengono sempre più un valido supporto alle tecniche di rilevamento satellitare. Esse sono al tempo stesso un’efficace materializzazione del sistema di riferimento e un utile ausilio ad applicazioni di rilevamento topografico e di monitoraggio per il controllo di deformazioni. Alle ormai classiche applicazioni statiche in post-processamento, si affiancano le misure in tempo reale sempre più utilizzate e richieste dall’utenza professionale. In tutti i casi risulta molto importante la determinazione di coordinate precise per le stazioni permanenti, al punto che si è deciso di effettuarla tramite differenti ambienti di calcolo. Sono stati confrontati il Bernese, il Gamit (che condividono l’approccio differenziato) e il Gipsy (che utilizza l’approccio indifferenziato). L’uso di tre software ha reso indispensabile l’individuazione di una strategia di calcolo comune in grado di garantire che, i dati ancillari e i parametri fisici adottati, non costituiscano fonte di diversificazione tra le soluzioni ottenute. L’analisi di reti di dimensioni nazionali oppure di reti locali per lunghi intervalli di tempo, comporta il processamento di migliaia se non decine di migliaia di file; a ciò si aggiunge che, talora a causa di banali errori, oppure al fine di elaborare test scientifici, spesso risulta necessario reiterare le elaborazioni. Molte risorse sono quindi state investite nella messa a punto di procedure automatiche finalizzate, da un lato alla preparazione degli archivi e dall’altro all’analisi dei risultati e al loro confronto qualora si sia in possesso di più soluzioni. Dette procedure sono state sviluppate elaborando i dataset più significativi messi a disposizione del DISTART (Dipartimento di Ingegneria delle Strutture, dei Trasporti, delle Acque, del Rilevamento del Territorio - Università di Bologna). E’ stato così possibile, al tempo stesso, calcolare la posizione delle stazioni permanenti di alcune importanti reti locali e nazionali e confrontare taluni fra i più importanti codici scientifici che assolvono a tale funzione. Per quanto attiene il confronto fra i diversi software si è verificato che: • le soluzioni ottenute dal Bernese e da Gamit (i due software differenziati) sono sempre in perfetto accordo; • le soluzioni Gipsy (che utilizza il metodo indifferenziato) risultano, quasi sempre, leggermente più disperse rispetto a quelle degli altri software e mostrano talvolta delle apprezzabili differenze numeriche rispetto alle altre soluzioni, soprattutto per quanto attiene la coordinata Est; le differenze sono però contenute in pochi millimetri e le rette che descrivono i trend sono comunque praticamente parallele a quelle degli altri due codici; • il citato bias in Est tra Gipsy e le soluzioni differenziate, è più evidente in presenza di determinate combinazioni Antenna/Radome e sembra essere legato all’uso delle calibrazioni assolute da parte dei diversi software. E’ necessario altresì considerare che Gipsy è sensibilmente più veloce dei codici differenziati e soprattutto che, con la procedura indifferenziata, il file di ciascuna stazione di ciascun giorno, viene elaborato indipendentemente dagli altri, con evidente maggior elasticità di gestione: se si individua un errore strumentale su di una singola stazione o se si decide di aggiungere o togliere una stazione dalla rete, non risulta necessario il ricalcolo dell’intera rete. Insieme alle altre reti è stato possibile analizzare la Rete Dinamica Nazionale (RDN), non solo i 28 giorni che hanno dato luogo alla sua prima definizione, bensì anche ulteriori quattro intervalli temporali di 28 giorni, intercalati di sei mesi e che coprono quindi un intervallo temporale complessivo pari a due anni. Si è così potuto verificare che la RDN può essere utilizzata per l’inserimento in ITRF05 (International Terrestrial Reference Frame) di una qualsiasi rete regionale italiana nonostante l’intervallo temporale ancora limitato. Da un lato sono state stimate le velocità ITRF (puramente indicative e non ufficiali) delle stazioni RDN e, dall’altro, è stata effettuata una prova di inquadramento di una rete regionale in ITRF, tramite RDN, e si è verificato che non si hanno differenze apprezzabili rispetto all’inquadramento in ITRF, tramite un congruo numero di stazioni IGS/EUREF (International GNSS Service / European REference Frame, SubCommission for Europe dello International Association of Geodesy).

La canzone sociale in Italia e in Francia tra protesta, nazione e rivoluzione (1830-1870)

La tesi di ricerca si propone di esaminare due tipologie della canzone sociale nel XIX secolo, ed in particolare attorno al 1848. Lo studio del canto nei contesti presi in esame (l’Italia e la Francia) viene analizzato attraverso due piste di ricerca parallele tra loro. Da una parte si è utilizzato il concetto di sociabilité per conoscere i luoghi di produzione e di diffusione del canto (l’importanza della strada, dell’osteria, delle goguette parigine, degli chansonniers des rues e dei cantastorie) e le circostanze di utilizzazione della canzone (la canzone in quanto forma d’espressione orale ma anche come scrittura murale, foglio volante e volantino). Dall’altra l’analisi si è focalizzata sui contenuti dei testi musicali per mette in luce le differenti tematiche, le immagini linguistiche e le figure retoriche cantate dall’artigiano-operaio per far emergere le differenze dell’idea di nazione tra i due contesti presi in esame. L’attenzione posta alla comparazione condurrà all’evidenziazione di punti di contatto tra le due nazioni. Il canto, infatti, costituisce un terreno privilegiato per comprendere l’immagine dell’“altro”: quale immagine possedevano i lavoratori francesi dell’Italia risorgimentale? E gli artigiani italiani come percepivano la nazione francese? Il canto viene analizzato non solamente come un “testo” ma anche come una “pratica sociale”. Queste operazioni permetteranno di sondare più in profondità la funzione sociale svolta dalla canzone all’interno della cultura popolare e la sua importanza in quanto forma d’espressione e vettore di politicizzazione. La duplice utilizzazione del canto, in quanto “testo” e “pratica”, consente di inserire la ricerca all’interno di un filone storiografico che dalla storia sociale si muove a quella culturale. La canzone sociale rappresenta un fertile terreno di ricerca, non solamente all’interno di un singolo territorio nazionale, ma possiede un prezioso valore euristico in funzione comparativa.

La lucha del Derecho contra el negacionismo: una peligrosa frontera. Particular estudio de los ordenamientos italiano y español

En la sociedad europea crece la preocupación por el retorno de tendencias fascistas y neonazis y por la extensión de ideologías xenófobas y antisemitas, algunas de ellas alimentadas a partir de tesis de negacionistas de aquellos trágicos eventos de nuestra historia reciente. La lucha frente a los discursos negacionistas se ha llevado más allá del ámbito social y académico, y se ha propuesto la incorporación en los ordenamientos jurídicos europeos de tipos penales específicos que incriminan este tipo de discurso: negar, banalizar, o justificar el Holocausto u otros genocidios o graves crímenes contra la humanidad. Esta legislación, que encuentra su mayor expresión en la Decisión marco 2008/913/JAI, aunque castiga un discurso socialmente repugnante, sin embargo presenta dudas en cuanto a su legitimidad con un sistema de libertades erigido sobre el pilar del pluralismo propio de los Estados democráticos. Surge así la cuestión de si pueden estar surgiendo «nuevos» delitos de opinión y a ello se dedica entonces la presente tesis. El objetivo concreto de este trabajo será analizar esta política-criminal para proponer una configuración del delito de negacionismo compatible con la libertad de expresión, aunque se cuestionará la conveniencia de castigar penalmente a través de un específico delito este tipo de conductas. En particular se pretende responder a tres preguntas: en primer lugar, ¿el discurso negacionista debe ampararse prima facie por la libertad de expresión en un ordenamiento abierto y personalista y cuáles podrían ser las «reglas» que podrían servir como criterio para limitar este género de manifestaciones? La segunda pregunta sería entonces: ¿Cómo podría construirse un tipo penal respetuoso con los principios constitucionales y penales que específicamente incriminara este género de conductas? Y, como última pregunta: ¿Es conveniente o adecuada una política criminal que lleve a crear un específico delito de negacionismo?

La cooperazione dell'UE nella creazione di uno spazio sicuro nella globalizzazione come possibile modello per la regione dell'Asia Centrale

Gli ultimi anni hanno visto importanti cambiamenti positivi nella cooperazione interstatale in Asia centrale. Crescenti minacce come il terrorismo internazionale, l'estremismo religioso e politico, il traffico di droga, ecc, causati dagli interessi geopolitici e geo-economici delle potenze mondiali, hanno contribuito alla formazione di una politica estera più coordinata e coerente degli Stati della regione. Questo processo si manifesta nella partecipazione attiva dell’istituzionalizzazione della Shanghai Organizzazione del Commonwealth (SOC), Conferenza sulle misure di costruzione d’interazione e fiducia in Asia (CICA) e Organizzazione del Trattato di Sicurezza Collettiva (CSTO). Problemi moderni di sicurezza in Asia centrale dovrebbero essere risolti in dei nuovi modi, non convenzionali. Le nuove minacce alla sicurezza richiedono modi non standard per risolvere il problema. Considerate le differenze fondamentali dell'Unione europea e degli Stati dell'Asia centrale nei valori e dal punto di vista in materia di sicurezza. I paesi dell'Asia centrale non sono pronti per l'integrazione politica. Nonostante questo, nell’Asia centrale sono state adottate misure per contrastare le minacce non convenzionali. L’esperienza europea di unire gli sforzi della regione per garantire la sicurezza interna, può essere utilizzata dai paesi dell'Asia centrale, soprattutto, in primo luogo sulla formazione del quadro istituzionale e giuridico per la cooperazione operativa delle forze dell'ordine per le seguenti aree: • prevenzione del traffico di droga attraverso gli Stati dell'Asia centrale; • lotta contro nuove forme di terrorismo ed estremismo; • limitare la dimensione della migrazione clandestina; • migliorare la protezione giuridica dei cittadini. Fino a poco tempo fa, questi temi hanno ricevuto poca attenzione, sia nella teoria sia nella pratica, poiché i problemi di sicurezza della società erano principalmente ridotti per evitare il pericolo di guerra.