1,327 research outputs found
Intermediate Institutions for Interactive Learning Processes in a Governance Perspective: the Case of Aeronautic Industry in Campania Region.
The present paper presents the results of the empirical analysis on fifteen enterprises and twenty no-industrial organizations involved at different level in the Aeronautical Cluster in the Campania Region. Information and data on the selected sample are colleted both by a study of the industrial sector, and also by suitable questionnaires and interviews, that the authors have submitted to the entrepreneurs and to the top managers of either the enterprises or the no-industrial organizations. The authors have focalized their study by applying the SWOT analysis on the following issues: ĂąâŹÂą the clusterâs structure by analysing the relational skill developed by single actors of the cluster and by their impact on the innovation capacity of the enterprises; ĂąâŹÂą the effectiveness of clusterâs governance strategies and how different actors actually participate to the local development processes of the aeronautical industrial sector. On these bases the authors wanted to deduce possible policy options for different kind of actors to optimize the clusterâs governance. Particularly they will describe in the present paper some indications to: 1) the SMEâs that present strong relations with customers but low integration with large part of the others actors, i.e. with no-customers enterprises; 2) the large enterprises related to the industrial policies and to the suppliers' governance; 3) the policy makers at local level and the intermediate institutions for a better support of the local enterprises. In fact, the research results are based on the conscientious awareness that the analyzed sector is at a critical point, for which it is necessary that all the actors involved put together their efforts in order to steer and to direct the development process, both by identifying participative mechanisms at local level and also by strengthening those exogenous elements which are able to promote local development. Obviously only part of the criticisms can be solved at local and national level and some of them can be solved only partially. This observation opens the question of policy at the international level which can be determinate only with a more exhaustive integration into transnational networks. The research described in the present paper has been undertaken within the framework of the project: ĂąâŹĆIKINET â International Knowledge and Innovation Networkù⏠(EU FP6, NĂ° CIT2-CT-2004-506242).
Development of a coherent ultrafast transmission electron microscope based on a laser-driven cold field emission source
L'Ă©tude de la physique des systĂšmes Ă l'Ă©chelle nanomĂ©trique nĂ©cessite idĂ©alement une rĂ©solution spatiale atomique et une rĂ©solution temporelle de l'ordre de la femtoseconde. La microscopie Ă©lectronique en transmission ultra-rapide (UTEM), qui combine une rĂ©solution temporelle infĂ©rieure Ă la picoseconde et une rĂ©solution spatiale nanomĂ©trique, est rĂ©cemment apparue comme un outil unique dotĂ© de rĂ©solutions spatio-temporelles sans prĂ©cĂ©dent. Cependant, les performances des premiers UTEMs Ă©taient limitĂ©es par la brillance des photocathodes utilisĂ©es comme source d'Ă©lectrons ultra-rapide. Dans ce contexte, il a Ă©tĂ© vite rĂ©alisĂ© que les UTEMs utilisant des sources d'Ă©lectrons dĂ©clenchĂ©es par laser et basĂ©es sur des pointes mĂ©talliques comme Ă©metteur, permettraient de dĂ©passer cette limitation. L'objectif de cette thĂšse est de dĂ©crire le dĂ©veloppement d'un microscope Ă©lectronique en transmission ultra-rapide basĂ© sur ce type de source dites " source Ă Ă©mission de champ froide ", pouvant fonctionner en mode continu ou ultra-rapide. L'Ă©mission d'Ă©lectrons d'une nanopointe de tungstĂšne est dĂ©clenchĂ©e par des impulsions laser femtosecondes, qui sont fortement focalisĂ©es par des composants optiques insĂ©rĂ©s proche de la cathode. La brillance mesurĂ©e est la plus grande mesurĂ©e Ă ce jour dans un UTEM. En associant cette nouvelle source de brillance Ă©levĂ©e Ă un systĂšme d'injection/cathodoluminescence composĂ© d'un miroir parabolique installĂ© au-dessus du porte-Ă©chantillon, l'UTEM peut ĂȘtre utilisĂ© pour rĂ©aliser des expĂ©riences TEM-pompe-sonde ultra-rapides rĂ©solues dans le temps. Les possibilitĂ©s d'un tel instrument pour l'imagerie ultra-rapide, la diffraction, l'holographie Ă©lectronique et la spectroscopie sont prĂ©sentĂ©es. Une attention particuliĂšre a Ă©tĂ© accordĂ©e aux applications en nano-optique. La spectroscopie Ă©lectronique de gain d'Ă©nergie (EEGS) permet notamment d'Ă©tudier les excitations optiques de nano-systĂšmes Ă travers les modifications du spectre d'Ă©nergie des Ă©lectrons. La possibilitĂ© de synchroniser facilement les impulsions d'Ă©lectrons libres ultra-courts avec l'excitation optique de l'Ă©chantillon dans les UTEM est essentielle pour l'observation d'interactions Ă©lectron/photon fortement non linĂ©aires. Ces expĂ©riences nous ont permis de caractĂ©riser les propriĂ©tĂ©s spectro-temporelles du faisceau d'Ă©lectrons ultra-courts. La derniĂšre partie propose une discussion des premiĂšres expĂ©riences d'holographie Ă©lectronique hors-axe rĂ©alisĂ©es avec des impulsions Ă©lectroniques ultra-rapides. En effet, la dose d'Ă©lectrons dans le plan de l'Ă©chantillon Ă©tant considĂ©rablement rĂ©duite en raison du faible taux de rĂ©pĂ©tition du train d'impulsions Ă©lectronique, les hologrammes ultra-rapides sont obtenus dans des conditions dites " low dose " complexes. En consĂ©quence, les paramĂštres expĂ©rimentaux couramment utilisĂ©s pour l'acquisition d'hologrammes avec des TEM conventionnels ne peuvent pas ĂȘtre directement utilisĂ©s en mode ultra-rapide. Des Ă©tudes expĂ©rimentales ont Ă©tĂ© rĂ©alisĂ©es pour dĂ©terminer les conditions optimales pour l'holographie Ă©lectronique hors-axe ultra-rapide. L'influence de la dose, la longueur de cohĂ©rence de la source, les conditions d'illumination et les instabilitĂ©s de l'instrument ont Ă©tĂ© systĂ©matiquement prises en compte.The investigation of the physics of nanoscale systems ideally requires atomic spatial resolution and femtosecond time-resolution. Ultrafast Transmission Electron Microscopy (UTEM) combining subpicosecond temporal resolution and nanometer spatial resolution has recently emerged as a unique tool with unprecedented spatio-temporal resolutions. However, the performances of the first UTEMs were limited by the brightness of the photocathodes used as ultrafast electron source. In this context, it was soon realized that UTEMs relying on laser-driven electron sources based on nanoscale emitters would overcome this limitation. The aim of this thesis is to report the development of an ultrafast Transmission Electron Microscope based on a cold field emission source, which can operate either in DC or ultrafast mode. Electron emission from a tungsten nanotip is triggered by femtosecond laser pulses, which are tightly focused by optical components integrated inside a cold-field emission source close to the cathode. The measured brightness is the largest reported so far for UTEMs. Combining this new high brightness source with an injection/Cathodoluminescence system, composed of a parabolic mirror placed above the sample holder, the UTEM can be used to perform time-resolved ultrafast pump-probe TEM experiments. The possibilities of such an instrument for ultrafast imaging, diffraction, electron holography and spectroscopy are presented. Particular attention has been paid on applications in nano-optics. In particular, Electron Energy Gain Spectroscopy (EEGS) allows to investigate the optical excitations of nanosystems in the energy domain. The ability to easily synchronize ultrashort free electron pulses with the optical excitation of the sample in UTEMs is essential for the observation of strongly nonlinear electron/photon interactions. These experiments will enable us to characterize the spectro-temporal properties of the ultrashort electron beam. Off-axis electron holography performed with ultrafast electron pulses are finally discussed. The electron dose in the specimen plane is considerably reduced due to the low repetition rate of the electron pulse train. This peculiar property of ultrafast FE-TEMs implies that ultrafast holograms are acquired in low-dose-like conditions. As a consequence, the experimental parameters commonly used for the acquisition of off-axis electron holograms with conventional TEMs cannot be directly implemented in the ultrafast mode. Experimental studies were performed to find the optimum conditions for ultrafast off-axis electron holography. Influence of the dose, the coherence length of the source, the illumination condition and the instrument instabilities have been addressed
Freeing Software and Opening Space: Social Forums and the Cultural Politics of Technology
The authors highlight how the World Social Forum (WSF), the annual meeting held by members of the anti-globalization or alter-globalization movement, has unexpected consequences for communications. They particularly explore what they refer to as the cultural politics of technology within the social forums through a comparative analysis of the political goals and struggles associated with Information and Communication Technologies (ICT) use within the global, European and the U.S. social forum processes
Freeing Software and Opening Space: Social Forums and the Cultural Politics of Technology
The authors highlight how the World Social Forum (WSF), the annual meeting held by members of the anti-globalization or alter-globalization movement, has unexpected consequences for communications. They particularly explore what they refer to as the cultural politics of technology within the social forums through a comparative analysis of the political goals and struggles associated with Information and Communication Technologies (ICT) use within the global, European and the U.S. social forum processes
Development of a high brightness ultrafast Transmission Electron Microscope based on a laser-driven cold field emission source
We report on the development of an ultrafast Transmission Electron Microscope
based on a cold field emission source which can operate in either DC or
ultrafast mode. Electron emission from a tungsten nanotip is triggered by
femtosecond laser pulses which are tightly focused by optical components
integrated inside a cold field emission source close to the cathode. The
properties of the electron probe (brightness, angular current density,
stability) are quantitatively determined. The measured brightness is the
largest reported so far for UTEMs. Examples of imaging, diffraction and
spectroscopy using ultrashort electron pulses are given. Finally, the potential
of this instrument is illustrated by performing electron holography in the
off-axis configuration using ultrashort electron pulses.Comment: 23 pages, 9 figure
Gap acceptance analysis in an urban intersection through a video acquired by an UAV
Purpose of this paper is to apply a methodology previously developed to achieve an accurate measurements of the real traffic condition thought the use of a video acquired by an UAV (Unmanned Aerial Vehicle) and a probe vehicle equipped with a differential GPS. The used methodology is not invasive and thus, it doesn't influence the driver behavior. The used equipment must not be compared to the traditional techniques of traffic flow but it can be used for particular situations in which the installation of fixed detectors is not economic.
In particular, we have analyzed the gap acceptance for an urban intersection between a main road with dual carriageway and two lanes in one direction, that connects the older town of Palermo with a main access roads (via E. Basile) and a secondary road used for local traffic and composed by a single carriageway with one lane for each direction (via U. Solarino)
Relation Between TDEC, Extinction Ratio and Chromatic Dispersion in 50G PON
We evaluate TDEC in a 50G-PON downstream through experiments and show the relation with receiver sensitivity at different fiber lengths and ER. The results show that TDEC effectively follows the penalty induced by transmission impairments
Urban traffic analysis through an UAV
In order to realize a precise and accurate traffic study, a method to evaluate the real traffic flow conditions in urban areas
based on videos acquired by an UAV, Unmanned Aerial Vehicle, is proposed. In this way it does not require additional
equipment to earth and, not being invasive, does not influence the driver behavior.
This paper presents the results obtained in terms of vehicular traffic flow along a way in the city of Palermo. The results have
been compared to experiments using macroscopic simulation models and the eventually differences have been discussed
New mobility strategies for the development of tourism in Sicily
Tourism and Transport is a well established and inseparable pair. An areas can increase the tourism in potentially own economy. This requires suitable accommodation and adequate transportation system. A positive synergy effects are induced to increase of the site. Transport is an important growth area for tourism and as a result. A better functioning of transport facilitates access to sites, decreases the cost of transport and increases tourist flows.
In Sicily there are a wealth of artistic, archaeological and natural sites, generating a tourist flows during the year. Despite this, the network of connections and services is precarious. Residents and visitors are inaccessible to certain geographical areas. Often airport nodes are isolated for tourist as residents and connections to main destinations are by road transport, because rail is not competitive. Congestion of the main arteries increase negative externalities related to road transport and for tourists increases the negative perception of the journey. In this paper we propose guidelines for sustainable tourism, by analyzing the supply of mobility. The case study examines the reality of the stretch of waterfront in Western Sicily (Palermo to Trapani), introducing a faster shipping service to facilitate accessibility to tourist sites along the coast, with a network of connections that includes airports nodes
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