420 research outputs found
Projective Systems of Noncommutative Lattices as a Pregeometric Substratum
We present an approximation to topological spaces by {\it noncommutative}
lattices. This approximation has a deep physical flavour based on the
impossibility to fully localize particles in any position measurement. The
original space being approximated is recovered out of a projective limit.Comment: 30 pages, Latex. To appear in `Quantum Groups and Fundamental
Physical Applications', ISI Guccia, Palermo, December 1997, D. Kastler and M.
Rosso Eds., (Nova Science Publishers, USA
Matrix Quantum Mechanics and Soliton Regularization of Noncommutative Field Theory
We construct an approximation to field theories on the noncommutative torus
based on soliton projections and partial isometries which together form a
matrix algebra of functions on the sum of two circles. The matrix quantum
mechanics is applied to the perturbative dynamics of scalar field theory, to
tachyon dynamics in string field theory, and to the Hamiltonian dynamics of
noncommutative gauge theory in two dimensions. We also describe the adiabatic
dynamics of solitons on the noncommutative torus and compare various classes of
noncommutative solitons on the torus and the plane.Comment: 70 pages, 4 figures; v2: References added and update
Dealing with Multilingualism in EU Institutions: The Implications of Enlargement from a Managerial Perspective
The European Union is a particularly complex experiment in the management of multilingualism, as compared to other international and supranational organizations, since each Member State has the right to have its own Language recognized as an official language. The 2004 enlargement proved especially challenging, with eight new official languages joining the list. The study compares the ways in which this challenge was met in different EU institutions. Good planning and differentiated managerial solutions, coherent with the mandate and constraints of different institutions, allowed the EU to manage a complex transition in such a way to balance successfully the pressure to control costs and the need to ensure democratic participation to all EU citizens, irrespective of their Language skills
Il ruolo delle risorse immateriali nell'esercizio della funzione di public governance: da modello teorico a pratica gestionale
In ricordo del professor Roberto Gusmani (1935-2009), gi\ue0 Rettore e storico Decano dell'Universit\ue0 di Udine, prestigioso glottologo di fama internazionale e stimatissimo docente nelle Facolt\ue0 di Lingue e di Lettere, \ue8 riunita in quest'opera in due volumi una cospicua serie di rigorosi e importanti saggi, sia di docenti udinesi che di autorevoli studiosi di linguistica italiani e stranieri. Nel primo volume numerosi docenti delle Facolt\ue0 di Lingue e di Lettere dell'Ateneo udinese si sono impegnati, con passione e acribia, nelle rispettive discipline. I saggi cos\uec raccolti spaziano, con rigore e vivacit\ue0, dalla storia alla letteratura inglese, dalla geografia alla letteratura italiana, dalla pedagogia alla letteratura francese. Nel secondo volume (in due tomi) la comunit\ue0 scientifica dei linguisti ha testimoniato con la sua larga e qualificata partecipazione la continuit\ue0 della lezione di Gusmani
Thermal Conductivity Measurements for Trans-1,3,3,3-Tetrafluoropropene (R1234ze(E)) in Liquid Phase
Photoprocessing of formamide ice: route towards prebiotic chemistry in space
Aims. Formamide (HCONH2) is the simplest molecule containing the peptide bond
first detected in the gas phase in Orion-KL and SgrB2. In recent years, it has
been observed in high temperature regions such as hot corinos, where thermal
desorption is responsible for the sublimation of frozen mantles into the gas
phase. The interpretation of observations can benefit from information gathered
in the laboratory, where it is possible to simulate the thermal desorption
process and to study formamide under simulated space conditions such as UV
irradiation. Methods. Here, two laboratory analyses are reported: we studied
formamide photo-stability under UV irradiation when it is adsorbed by space
relevant minerals at 63 K and in the vacuum regime. We also investigated
temperature programmed desorption of pure formamide ice in the presence of TiO2
dust before and after UV irradiation. Results. Through these analyses, the
effects of UV degradation and the interaction between formamide and different
minerals are compared.We find that silicates, both hydrates and anhydrates,
offer molecules a higher level of protection from UV degradation than mineral
oxides. The desorption temperature found for pure formamide is 220 K. The
desorption temperature increases to 250 K when the formamide desorbs from the
surface of TiO2 grains. Conclusions. Through the experiments outlined here, it
is possible to follow the desorption of formamide and its fragments, simulate
the desorption process in star forming regions and hot corinos, and constrain
parameters such as the thermal desorption temperature of formamide and its
fragments and the binding energies involved. Our results offer support to
observational data and improve our understanding of the role of the grain
surface in enriching the chemistry in space.Comment: In press Astronomy and Astrophysics, 13 pages, 12 figure
Advanced European Re-Entry System Based on Inflatable Heat Shields: Detailed Design (EFESTO project)
The European Union H2020 EFESTO project is coordinated by DEIMOS Space with the end goals of improving the European TRL of Inflatable Heat Shields for re-entry vehicles (from 3 to 4/5) and paving the way towards further improvements (TRL 6 with a future In-Orbit Demonstrator, IOD). This paper presents the project objectives and the initial results of the detailed design of atmospheric entry missions based on the applications of advanced thermal protection systems implementing inflatable heat shields (flexible TPS and inflatable structures), according to aerothermodynamics constraints for future in-orbit demonstration. Placing the future IOD mission in the context of ongoing and future efforts in the European context is also one of the project goals. Two key applications, Mars Robotic Exploration and Reusable Small Launchers Upper Stages, have been identified. For the Mars Application, the robotic exploration mission class resulted in a 10 m diameter Hypersonic Inflatable Aerodynamic Decelerator (HIAD) class, combined with Supersonic Retro-Propulsion (SRP, activated about Mach 2.3) to deliver about 2800 kg of payload at MOLA +2 km. For the Earth Application, the VEGA upper stage (AVUM) has been selected as baseline case study. The current mission foresees a deorbiting from SSO orbit, a controlled entry phase (BC of about 30 kg/m2) and combines the use of a HIAD (4.5m diameter class) with parachutes and parafoil for Mid-Air-Capturing (MAR) with a helicopter. Beyond feasibility of the entry mission phase and system design with an inflated IAD, integration aspects have a key impact in the specific design solutions adopted, due to the nature of an inflatable heatshield. For both considered application cases feasible architectures are developed responding to the challenge of integrating the HIAD into the system in compliance with geometric and functional requirements. While the HIAD in folded state prior to inflation must fit in the available volume, it has limitations with respect to the density imposing a minimum cross section of the stowage volume. Simultaneously requirements with respect to the centre of gravity position during re-entry with an inflated HIAD must be respected for stability and controllability reasons. Other architectural considerations such as payload integration for the application on a launcher upper stage must be considered. Finally, heat loads constraints are considered for the trajectory and TPS deign choices due to important fluid-structure interactions. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 821801
Innovative Technologies and Materials for more Sustainable Transportation Infrastructures
nnovative technologies and materials can develop the goals stated in the UN resolution A/RES/70/1. To be more precise, low-noise road pavements (for example Porous asphalt concretes, asphalt rubberised mixture, and texture-optimised pavements) have volumetric, surface (such as drainability, texture, friction and acoustic performance), and mechanistic properties that decay over time. This depends on the particular technology used and on the many variables, processes, and phenomena with consequences in terms of safety, quietness, and budget. In light of these issues, the objectives of this study are confined into discussing several prospective developments related to the improvement of the road pavements currently used in the urban context. A new methodology aimed at improving the design of the main properties of a road pavement is presented.The abovementioned methodology was set up based on laboratory and on-site tests, which were carried out over recent decades in order to monitor the variation of surface and volumetric properties over time. Road surfaces with premium properties (such as low-noise emissions) can increase pavement and acoustic durability, and the proposed methodology can greatly improve the overall sustainability of current transportation infrastructures, fulfilling some of the goals stated in the UN Resolution A/RES/70/1. Tecnologie e materiali innovativi per infrastrutture di trasporto più sostenibiliLe tecnologie e i materiali innovativi possono favorire gli obiettivi contenuti nella risoluzione A/RES/70/1 delle Nazioni Unite. Le pavimentazioni stradali a bassa rumorosità (ad esempio le pavimentazioni porose, le miscele bituminose con gomma e le pavimentazioni con tessitura ottimizzata) hanno proprietà volumetriche, superficiali (quali drenabilità, tessitura, aderenza e prestazioni acustiche) e proprietà meccaniche che decadono nel tempo. Ciò dipende dalla particolare tecnologia utilizzata e da molteplici variabili. Molti processi e fenomeni sono coinvolti, con conseguenze in termini di sicurezza, rumorosità e budget. Alla luce di questi problemi, gli obiettivi di questo studio riguardano la messa a punto di una metodologia volta a migliorare la progettazione delle principali proprietà di una pavimentazione stradale e in particolare di quelle relative alla superficie. Le proprietà superficiali e volumetriche sono state monitorate, analizzate, in laboratorio e in situ. I risultati mostrano che l'uso di superfici stradali “speciali” (aventi, ad esempio, bassa emissione di rumore) può aumentare la durata complessiva della pavimentazione e che il metodo messo a punto può migliorare notevolmente la sostenibilità complessiva delle infrastrutture di trasporto, raggiungendo alcuni degli obiettivi indicati nella risoluzione A/RES/70/1.Innovative technologies and materials can develop the goals stated in the UN resolution A/RES/70/1. To be more precise, low-noise road pavements (for example Porous asphalt concretes, asphalt rubberised mixture, and texture-optimised pavements) have volumetric, surface (such as drainability, texture, friction and acoustic performance), and mechanistic properties that decay over time. This depends on the particular technology used and on the many variables, processes, and phenomena with consequences in terms of safety, quietness, and budget. In light of these issues, the objectives of this study are confined into discussing several prospective developments related to the improvement of the road pavements currently used in the urban context. A new methodology aimed at improving the design of the main properties of a road pavement is presented.The abovementioned methodology was set up based on laboratory and on-site tests, which were carried out over recent decades in order to monitor the variation of surface and volumetric properties over time. Road surfaces with premium properties (such as low-noise emissions) can increase pavement and acoustic durability, and the proposed methodology can greatly improve the overall sustainability of current transportation infrastructures, fulfilling some of the goals stated in the UN Resolution A/RES/70/1. Tecnologie e materiali innovativi per infrastrutture di trasporto più sostenibiliLe tecnologie e i materiali innovativi possono favorire gli obiettivi contenuti nella risoluzione A/RES/70/1 delle Nazioni Unite. Le pavimentazioni stradali a bassa rumorosità (ad esempio le pavimentazioni porose, le miscele bituminose con gomma e le pavimentazioni con tessitura ottimizzata) hanno proprietà volumetriche, superficiali (quali drenabilità, tessitura, aderenza e prestazioni acustiche) e proprietà meccaniche che decadono nel tempo. Ciò dipende dalla particolare tecnologia utilizzata e da molteplici variabili. Molti processi e fenomeni sono coinvolti, con conseguenze in termini di sicurezza, rumorosità e budget. Alla luce di questi problemi, gli obiettivi di questo studio riguardano la messa a punto di una metodologia volta a migliorare la progettazione delle principali proprietà di una pavimentazione stradale e in particolare di quelle relative alla superficie. Le proprietà superficiali e volumetriche sono state monitorate, analizzate, in laboratorio e in situ. I risultati mostrano che l'uso di superfici stradali “speciali” (aventi, ad esempio, bassa emissione di rumore) può aumentare la durata complessiva della pavimentazione e che il metodo messo a punto può migliorare notevolmente la sostenibilità complessiva delle infrastrutture di trasporto, raggiungendo alcuni degli obiettivi indicati nella risoluzione A/RES/70/1
An Analysis of Word2Vec for the Italian Language
Word representation is fundamental in NLP tasks, because it is precisely from
the coding of semantic closeness between words that it is possible to think of
teaching a machine to understand text. Despite the spread of word embedding
concepts, still few are the achievements in linguistic contexts other than
English. In this work, analysing the semantic capacity of the Word2Vec
algorithm, an embedding for the Italian language is produced. Parameter setting
such as the number of epochs, the size of the context window and the number of
negatively backpropagated samples is explored.Comment: Presented at the 2019 Italian Workshop on Neural Networks (WIRN'19) -
June 201
A New Matrix Model for Noncommutative Field Theory
We describe a new regularization of quantum field theory on the
noncommutative torus by means of one-dimensional matrix models. The
construction is based on the Elliott-Evans inductive limit decomposition of the
noncommutative torus algebra. The matrix trajectories are obtained via the
expansion of fields in a basis of new noncommutative solitons described by
projections and partial isometries. The matrix quantum mechanics are compared
with the usual zero-dimensional matrix model regularizations and some
applications are sketched.Comment: 14 pages, 2 figure
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